3673 lines
105 KiB
C
3673 lines
105 KiB
C
/*
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* Copyright (c) 2000-2022 Apple Inc. All rights reserved.
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*
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* @APPLE_OSREFERENCE_LICENSE_HEADER_START@
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*
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* This file contains Original Code and/or Modifications of Original Code
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* as defined in and that are subject to the Apple Public Source License
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* Version 2.0 (the 'License'). You may not use this file except in
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* compliance with the License. The rights granted to you under the License
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* may not be used to create, or enable the creation or redistribution of,
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* unlawful or unlicensed copies of an Apple operating system, or to
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* circumvent, violate, or enable the circumvention or violation of, any
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* terms of an Apple operating system software license agreement.
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*
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* Please obtain a copy of the License at
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* http://www.opensource.apple.com/apsl/ and read it before using this file.
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*
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* The Original Code and all software distributed under the License are
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* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
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* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
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* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
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* Please see the License for the specific language governing rights and
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* limitations under the License.
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*
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* @APPLE_OSREFERENCE_LICENSE_HEADER_END@
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*/
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/*
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* Copyright (c) 1982, 1986, 1988, 1990, 1993, 1995
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* The Regents of the University of California. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* @(#)tcp_output.c 8.4 (Berkeley) 5/24/95
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* $FreeBSD: src/sys/netinet/tcp_output.c,v 1.39.2.10 2001/07/07 04:30:38 silby Exp $
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*/
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/*
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* NOTICE: This file was modified by SPARTA, Inc. in 2005 to introduce
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* support for mandatory and extensible security protections. This notice
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* is included in support of clause 2.2 (b) of the Apple Public License,
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* Version 2.0.
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*/
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#define _IP_VHL
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#include "tcp_includes.h"
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/kernel.h>
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#include <sys/sysctl.h>
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#include <sys/mbuf.h>
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#include <sys/domain.h>
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#include <sys/protosw.h>
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#include <sys/socket.h>
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#include <sys/socketvar.h>
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#include <net/route.h>
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#include <net/ntstat.h>
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#include <net/if_var.h>
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#include <net/if.h>
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#include <net/if_types.h>
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#include <net/dlil.h>
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#include <netinet/in.h>
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#include <netinet/in_systm.h>
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#include <netinet/in_var.h>
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#include <netinet/in_tclass.h>
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#include <netinet/ip.h>
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#include <netinet/in_pcb.h>
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#include <netinet/ip_var.h>
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#include <mach/sdt.h>
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#include <netinet6/in6_pcb.h>
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#include <netinet/ip6.h>
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#include <netinet6/ip6_var.h>
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#include <netinet/tcp.h>
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#include <netinet/tcp_cache.h>
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#include <netinet/tcp_fsm.h>
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#include <netinet/tcp_seq.h>
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#include <netinet/tcp_timer.h>
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#include <netinet/tcp_var.h>
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#include <netinet/tcpip.h>
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#include <netinet/tcp_cc.h>
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#if TCPDEBUG
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#include <netinet/tcp_debug.h>
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#endif
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#include <netinet/tcp_log.h>
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#include <sys/kdebug.h>
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#include <mach/sdt.h>
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#if IPSEC
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#include <netinet6/ipsec.h>
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#endif /*IPSEC*/
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#if MPTCP
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#include <netinet/mptcp_var.h>
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#include <netinet/mptcp.h>
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#include <netinet/mptcp_opt.h>
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#include <netinet/mptcp_seq.h>
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#endif
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#include <corecrypto/ccaes.h>
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#define DBG_LAYER_BEG NETDBG_CODE(DBG_NETTCP, 1)
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#define DBG_LAYER_END NETDBG_CODE(DBG_NETTCP, 3)
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#define DBG_FNC_TCP_OUTPUT NETDBG_CODE(DBG_NETTCP, (4 << 8) | 1)
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SYSCTL_SKMEM_TCP_INT(OID_AUTO, path_mtu_discovery,
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CTLFLAG_RW | CTLFLAG_LOCKED, int, path_mtu_discovery, 1,
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"Enable Path MTU Discovery");
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SYSCTL_SKMEM_TCP_INT(OID_AUTO, local_slowstart_flightsize,
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CTLFLAG_RW | CTLFLAG_LOCKED, int, ss_fltsz_local, 8,
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"Slow start flight size for local networks");
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SYSCTL_SKMEM_TCP_INT(OID_AUTO, tso, CTLFLAG_RW | CTLFLAG_LOCKED,
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int, tcp_do_tso, 1, "Enable TCP Segmentation Offload");
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SYSCTL_SKMEM_TCP_INT(OID_AUTO, ecn_setup_percentage,
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CTLFLAG_RW | CTLFLAG_LOCKED, int, tcp_ecn_setup_percentage, 100,
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"Max ECN setup percentage");
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SYSCTL_SKMEM_TCP_INT(OID_AUTO, accurate_ecn,
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CTLFLAG_RW | CTLFLAG_LOCKED, int, tcp_acc_ecn, 0,
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"Accurate ECN mode (0: disable, 1: enable ACE feedback");
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// TO BE REMOVED
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SYSCTL_SKMEM_TCP_INT(OID_AUTO, do_ack_compression,
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CTLFLAG_RW | CTLFLAG_LOCKED, int, tcp_do_ack_compression, 1,
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"Enable TCP ACK compression (on (cell only): 1, off: 0, on (all interfaces): 2)");
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SYSCTL_SKMEM_TCP_INT(OID_AUTO, ack_compression_rate,
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CTLFLAG_RW | CTLFLAG_LOCKED, int, tcp_ack_compression_rate, TCP_COMP_CHANGE_RATE,
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"Rate at which we force sending new ACKs (in ms)");
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SYSCTL_SKMEM_TCP_INT(OID_AUTO, randomize_timestamps,
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CTLFLAG_RW | CTLFLAG_LOCKED, int, tcp_randomize_timestamps, 1,
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"Randomize TCP timestamps to prevent tracking (on: 1, off: 0)");
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static int
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sysctl_change_ecn_setting SYSCTL_HANDLER_ARGS
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{
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#pragma unused(oidp, arg1, arg2)
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int i, err = 0, changed = 0;
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struct ifnet *ifp;
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err = sysctl_io_number(req, tcp_ecn_outbound, sizeof(int32_t),
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&i, &changed);
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if (err != 0 || req->newptr == USER_ADDR_NULL) {
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return err;
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}
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if (changed) {
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if ((tcp_ecn_outbound == 0 || tcp_ecn_outbound == 1) &&
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(i == 0 || i == 1)) {
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tcp_ecn_outbound = i;
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SYSCTL_SKMEM_UPDATE_FIELD(tcp.ecn_initiate_out, tcp_ecn_outbound);
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return err;
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}
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if (tcp_ecn_outbound == 2 && (i == 0 || i == 1)) {
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/*
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* Reset ECN enable flags on non-cellular
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* interfaces so that the system default will take
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* over
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*/
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ifnet_head_lock_shared();
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TAILQ_FOREACH(ifp, &ifnet_head, if_link) {
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if (!IFNET_IS_CELLULAR(ifp)) {
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if_clear_eflags(ifp,
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IFEF_ECN_ENABLE |
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IFEF_ECN_DISABLE);
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}
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}
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ifnet_head_done();
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} else {
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/*
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* Set ECN enable flags on non-cellular
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* interfaces
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*/
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ifnet_head_lock_shared();
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TAILQ_FOREACH(ifp, &ifnet_head, if_link) {
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if (!IFNET_IS_CELLULAR(ifp)) {
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if_set_eflags(ifp, IFEF_ECN_ENABLE);
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if_clear_eflags(ifp, IFEF_ECN_DISABLE);
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}
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}
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ifnet_head_done();
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}
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tcp_ecn_outbound = i;
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SYSCTL_SKMEM_UPDATE_FIELD(tcp.ecn_initiate_out, tcp_ecn_outbound);
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}
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/* Change the other one too as the work is done */
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if (i == 2 || tcp_ecn_inbound == 2) {
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tcp_ecn_inbound = i;
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SYSCTL_SKMEM_UPDATE_FIELD(tcp.ecn_negotiate_in, tcp_ecn_inbound);
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}
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return err;
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}
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int tcp_ecn_outbound = 2;
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SYSCTL_PROC(_net_inet_tcp, OID_AUTO, ecn_initiate_out,
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CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_LOCKED, &tcp_ecn_outbound, 0,
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sysctl_change_ecn_setting, "IU",
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"Initiate ECN for outbound connections");
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int tcp_ecn_inbound = 2;
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SYSCTL_PROC(_net_inet_tcp, OID_AUTO, ecn_negotiate_in,
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CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_LOCKED, &tcp_ecn_inbound, 0,
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sysctl_change_ecn_setting, "IU",
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"Initiate ECN for inbound connections");
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SYSCTL_SKMEM_TCP_INT(OID_AUTO, packetchain,
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CTLFLAG_RW | CTLFLAG_LOCKED, int, tcp_packet_chaining, 50,
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"Enable TCP output packet chaining");
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SYSCTL_SKMEM_TCP_INT(OID_AUTO, socket_unlocked_on_output,
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CTLFLAG_RW | CTLFLAG_LOCKED, int, tcp_output_unlocked, 1,
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"Unlock TCP when sending packets down to IP");
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SYSCTL_SKMEM_TCP_INT(OID_AUTO, min_iaj_win,
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CTLFLAG_RW | CTLFLAG_LOCKED, int, tcp_min_iaj_win, MIN_IAJ_WIN,
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"Minimum recv win based on inter-packet arrival jitter");
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SYSCTL_SKMEM_TCP_INT(OID_AUTO, acc_iaj_react_limit,
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CTLFLAG_RW | CTLFLAG_LOCKED, int, tcp_acc_iaj_react_limit,
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ACC_IAJ_REACT_LIMIT, "Accumulated IAJ when receiver starts to react");
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SYSCTL_SKMEM_TCP_INT(OID_AUTO, autosndbufinc,
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CTLFLAG_RW | CTLFLAG_LOCKED, uint32_t, tcp_autosndbuf_inc,
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8 * 1024, "Increment in send socket bufffer size");
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SYSCTL_SKMEM_TCP_INT(OID_AUTO, autosndbufmax,
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CTLFLAG_RW | CTLFLAG_LOCKED | CTLFLAG_KERN, uint32_t, tcp_autosndbuf_max, 2 * 1024 * 1024,
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"Maximum send socket buffer size");
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SYSCTL_SKMEM_TCP_INT(OID_AUTO, rtt_recvbg,
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CTLFLAG_RW | CTLFLAG_LOCKED, uint32_t, tcp_use_rtt_recvbg, 1,
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"Use RTT for bg recv algorithm");
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SYSCTL_SKMEM_TCP_INT(OID_AUTO, recv_throttle_minwin,
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CTLFLAG_RW | CTLFLAG_LOCKED, uint32_t, tcp_recv_throttle_minwin, 16 * 1024,
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"Minimum recv win for throttling");
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SYSCTL_SKMEM_TCP_INT(OID_AUTO, enable_tlp,
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CTLFLAG_RW | CTLFLAG_LOCKED,
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int32_t, tcp_enable_tlp, 1, "Enable Tail loss probe");
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static int32_t packchain_newlist = 0;
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static int32_t packchain_looped = 0;
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static int32_t packchain_sent = 0;
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/* temporary: for testing */
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#if IPSEC
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extern int ipsec_bypass;
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#endif
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extern int slowlink_wsize; /* window correction for slow links */
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extern u_int32_t kipf_count;
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static int tcp_ip_output(struct socket *, struct tcpcb *, struct mbuf *,
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int, struct mbuf *, int, int, boolean_t);
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static int tcp_recv_throttle(struct tcpcb *tp);
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__attribute__((noinline))
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static int32_t
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tcp_tfo_check(struct tcpcb *tp, int32_t len)
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{
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struct socket *so = tp->t_inpcb->inp_socket;
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unsigned int optlen = 0;
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unsigned int cookie_len;
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if (tp->t_flags & TF_NOOPT) {
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goto fallback;
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}
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if (!(tp->t_flagsext & TF_FASTOPEN_FORCE_ENABLE) &&
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!tcp_heuristic_do_tfo(tp)) {
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tp->t_tfo_stats |= TFO_S_HEURISTICS_DISABLE;
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tcpstat.tcps_tfo_heuristics_disable++;
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goto fallback;
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}
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if (so->so_flags1 & SOF1_DATA_AUTHENTICATED) {
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return len;
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}
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optlen += TCPOLEN_MAXSEG;
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if (tp->t_flags & TF_REQ_SCALE) {
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optlen += 4;
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}
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#if MPTCP
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if ((so->so_flags & SOF_MP_SUBFLOW) && mptcp_enable &&
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(tp->t_rxtshift <= mptcp_mpcap_retries ||
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(tptomptp(tp)->mpt_mpte->mpte_flags & MPTE_FORCE_ENABLE))) {
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optlen += sizeof(struct mptcp_mpcapable_opt_common) + sizeof(mptcp_key_t);
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}
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#endif /* MPTCP */
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if (tp->t_flags & TF_REQ_TSTMP) {
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optlen += TCPOLEN_TSTAMP_APPA;
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}
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if (SACK_ENABLED(tp)) {
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optlen += TCPOLEN_SACK_PERMITTED;
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}
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/* Now, decide whether to use TFO or not */
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/* Don't even bother trying if there is no space at all... */
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if (MAX_TCPOPTLEN - optlen < TCPOLEN_FASTOPEN_REQ) {
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goto fallback;
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}
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cookie_len = tcp_cache_get_cookie_len(tp);
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if (cookie_len == 0) {
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/* No cookie, so we request one */
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return 0;
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}
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/* There is not enough space for the cookie, so we cannot do TFO */
|
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if (MAX_TCPOPTLEN - optlen < cookie_len) {
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goto fallback;
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}
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|
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/* Do not send SYN+data if there is more in the queue than MSS */
|
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if (so->so_snd.sb_cc > (tp->t_maxopd - MAX_TCPOPTLEN)) {
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goto fallback;
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}
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|
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/* Ok, everything looks good. We can go on and do TFO */
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return len;
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fallback:
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tcp_disable_tfo(tp);
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return 0;
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}
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|
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/* Returns the number of bytes written to the TCP option-space */
|
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__attribute__((noinline))
|
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static unsigned int
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tcp_tfo_write_cookie_rep(struct tcpcb *tp, unsigned int optlen, u_char *opt)
|
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{
|
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u_char out[CCAES_BLOCK_SIZE];
|
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unsigned ret = 0;
|
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u_char *bp;
|
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|
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if (MAX_TCPOPTLEN - optlen <
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TCPOLEN_FASTOPEN_REQ + TFO_COOKIE_LEN_DEFAULT) {
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return ret;
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}
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|
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tcp_tfo_gen_cookie(tp->t_inpcb, out, sizeof(out));
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|
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bp = opt + optlen;
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|
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*bp++ = TCPOPT_FASTOPEN;
|
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*bp++ = 2 + TFO_COOKIE_LEN_DEFAULT;
|
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memcpy(bp, out, TFO_COOKIE_LEN_DEFAULT);
|
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ret += 2 + TFO_COOKIE_LEN_DEFAULT;
|
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|
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tp->t_tfo_stats |= TFO_S_COOKIE_SENT;
|
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tcpstat.tcps_tfo_cookie_sent++;
|
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|
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return ret;
|
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}
|
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|
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__attribute__((noinline))
|
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static unsigned int
|
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tcp_tfo_write_cookie(struct tcpcb *tp, unsigned int optlen, int32_t len,
|
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u_char *opt)
|
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{
|
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uint8_t tfo_len;
|
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struct socket *so = tp->t_inpcb->inp_socket;
|
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unsigned ret = 0;
|
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int res;
|
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u_char *bp;
|
|
|
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if (TCPOLEN_FASTOPEN_REQ > MAX_TCPOPTLEN - optlen) {
|
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return 0;
|
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}
|
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tfo_len = (uint8_t)(MAX_TCPOPTLEN - optlen - TCPOLEN_FASTOPEN_REQ);
|
|
|
|
if (so->so_flags1 & SOF1_DATA_AUTHENTICATED) {
|
|
/* If there is some data, let's track it */
|
|
if (len > 0) {
|
|
tp->t_tfo_stats |= TFO_S_SYN_DATA_SENT;
|
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tcpstat.tcps_tfo_syn_data_sent++;
|
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}
|
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|
|
return 0;
|
|
}
|
|
|
|
bp = opt + optlen;
|
|
|
|
/*
|
|
* The cookie will be copied in the appropriate place within the
|
|
* TCP-option space. That way we avoid the need for an intermediate
|
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* variable.
|
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*/
|
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res = tcp_cache_get_cookie(tp, bp + TCPOLEN_FASTOPEN_REQ, &tfo_len);
|
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if (res == 0) {
|
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*bp++ = TCPOPT_FASTOPEN;
|
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*bp++ = TCPOLEN_FASTOPEN_REQ;
|
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ret += TCPOLEN_FASTOPEN_REQ;
|
|
|
|
tp->t_tfo_flags |= TFO_F_COOKIE_REQ;
|
|
|
|
tp->t_tfo_stats |= TFO_S_COOKIE_REQ;
|
|
tcpstat.tcps_tfo_cookie_req++;
|
|
} else {
|
|
*bp++ = TCPOPT_FASTOPEN;
|
|
*bp++ = TCPOLEN_FASTOPEN_REQ + tfo_len;
|
|
|
|
ret += TCPOLEN_FASTOPEN_REQ + tfo_len;
|
|
|
|
tp->t_tfo_flags |= TFO_F_COOKIE_SENT;
|
|
|
|
/* If there is some data, let's track it */
|
|
if (len > 0) {
|
|
tp->t_tfo_stats |= TFO_S_SYN_DATA_SENT;
|
|
tcpstat.tcps_tfo_syn_data_sent++;
|
|
}
|
|
}
|
|
|
|
return ret;
|
|
}
|
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|
|
static inline bool
|
|
tcp_send_ecn_flags_on_syn(struct tcpcb *tp)
|
|
{
|
|
/* We allow Accurate ECN negotiation on first retransmission as well */
|
|
bool send_on_first_retrans = (tp->ecn_flags & TE_ACE_SETUPSENT) &&
|
|
(tp->t_rxtshift <= 1);
|
|
|
|
return !(tp->ecn_flags & (TE_SETUPSENT | TE_ACE_SETUPSENT)) || send_on_first_retrans;
|
|
}
|
|
|
|
void
|
|
tcp_set_ecn(struct tcpcb *tp, struct ifnet *ifp)
|
|
{
|
|
boolean_t inbound;
|
|
|
|
/*
|
|
* Socket option has precedence
|
|
*/
|
|
if (tp->ecn_flags & TE_ECN_MODE_ENABLE) {
|
|
tp->ecn_flags |= TE_ENABLE_ECN;
|
|
goto check_heuristic;
|
|
}
|
|
|
|
if (tp->ecn_flags & TE_ECN_MODE_DISABLE) {
|
|
tp->ecn_flags &= ~TE_ENABLE_ECN;
|
|
return;
|
|
}
|
|
/*
|
|
* Per interface setting comes next
|
|
*/
|
|
if (ifp != NULL) {
|
|
if (ifp->if_eflags & IFEF_ECN_ENABLE) {
|
|
tp->ecn_flags |= TE_ENABLE_ECN;
|
|
goto check_heuristic;
|
|
}
|
|
|
|
if (ifp->if_eflags & IFEF_ECN_DISABLE) {
|
|
tp->ecn_flags &= ~TE_ENABLE_ECN;
|
|
return;
|
|
}
|
|
}
|
|
/*
|
|
* System wide settings come last
|
|
*/
|
|
inbound = (tp->t_inpcb->inp_socket->so_head != NULL);
|
|
if ((inbound && tcp_ecn_inbound == 1) ||
|
|
(!inbound && tcp_ecn_outbound == 1)) {
|
|
tp->ecn_flags |= TE_ENABLE_ECN;
|
|
goto check_heuristic;
|
|
} else {
|
|
tp->ecn_flags &= ~TE_ENABLE_ECN;
|
|
}
|
|
|
|
return;
|
|
|
|
check_heuristic:
|
|
if (TCP_ACC_ECN_ENABLED(tp)) {
|
|
/* Allow ECN when Accurate ECN is enabled until heuristics are fixed */
|
|
tp->ecn_flags |= TE_ENABLE_ECN;
|
|
/* Set the accurate ECN state */
|
|
if (tp->t_client_accecn_state == tcp_connection_client_accurate_ecn_feature_disabled) {
|
|
tp->t_client_accecn_state = tcp_connection_client_accurate_ecn_feature_enabled;
|
|
}
|
|
if (tp->t_server_accecn_state == tcp_connection_server_accurate_ecn_feature_disabled) {
|
|
tp->t_server_accecn_state = tcp_connection_server_accurate_ecn_feature_enabled;
|
|
}
|
|
}
|
|
if (!tcp_heuristic_do_ecn(tp) && !TCP_ACC_ECN_ENABLED(tp)) {
|
|
/* Allow ECN when Accurate ECN is enabled until heuristics are fixed */
|
|
tp->ecn_flags &= ~TE_ENABLE_ECN;
|
|
}
|
|
/*
|
|
* If the interface setting, system-level setting and heuristics
|
|
* allow to enable ECN, randomly select 5% of connections to
|
|
* enable it
|
|
*/
|
|
if ((tp->ecn_flags & (TE_ECN_MODE_ENABLE | TE_ECN_MODE_DISABLE
|
|
| TE_ENABLE_ECN)) == TE_ENABLE_ECN) {
|
|
/*
|
|
* Use the random value in iss for randomizing
|
|
* this selection
|
|
*/
|
|
if ((tp->iss % 100) >= tcp_ecn_setup_percentage && !TCP_ACC_ECN_ENABLED(tp)) {
|
|
/* Don't disable Accurate ECN randomly */
|
|
tp->ecn_flags &= ~TE_ENABLE_ECN;
|
|
}
|
|
}
|
|
}
|
|
|
|
int
|
|
tcp_flight_size(struct tcpcb *tp)
|
|
{
|
|
int ret;
|
|
|
|
VERIFY(tp->sackhint.sack_bytes_acked >= 0);
|
|
VERIFY(tp->sackhint.sack_bytes_rexmit >= 0);
|
|
|
|
/*
|
|
* RFC6675, SetPipe (), SACK'd bytes are discounted. All the rest is still in-flight.
|
|
*/
|
|
ret = tp->snd_nxt - tp->snd_una - tp->sackhint.sack_bytes_acked;
|
|
|
|
if (ret < 0) {
|
|
/*
|
|
* This happens when the RTO-timer fires because snd_nxt gets artificially
|
|
* decreased. If we then receive some SACK-blogs, sack_bytes_acked is
|
|
* going to be high.
|
|
*/
|
|
ret = 0;
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* Either of ECT0 or ECT1 flag should be set
|
|
* when this function is called
|
|
*/
|
|
static void
|
|
tcp_add_accecn_option(struct tcpcb *tp, uint16_t flags, uint32_t *lp, uint8_t *optlen)
|
|
{
|
|
uint8_t max_len = TCP_MAXOLEN - *optlen;
|
|
uint8_t len = TCPOLEN_ACCECN_EMPTY;
|
|
|
|
uint32_t e1b = (uint32_t)(tp->t_rcv_ect1_bytes & TCP_ACO_MASK);
|
|
uint32_t e0b = (uint32_t)(tp->t_rcv_ect0_bytes & TCP_ACO_MASK);
|
|
uint32_t ceb = (uint32_t)(tp->t_rcv_ce_bytes & TCP_ACO_MASK);
|
|
|
|
if (max_len < TCPOLEN_ACCECN_EMPTY) {
|
|
TCP_LOG(tp, "not enough space to add any AccECN option");
|
|
return;
|
|
}
|
|
|
|
if (!(flags & TH_SYN || (tp->ecn_flags & TE_ACE_FINAL_ACK_3WHS) ||
|
|
tp->snd_una == tp->iss + 1 ||
|
|
tp->ecn_flags & (TE_ACO_ECT1 | TE_ACO_ECT0))) {
|
|
/*
|
|
* Since this is neither a SYN-ACK packet, nor the final ACK of
|
|
* the 3WHS (nor the first acked data segment) nor any of the ECT byte
|
|
* counter flags are set, no need to send the option.
|
|
*/
|
|
return;
|
|
}
|
|
|
|
if ((flags & (TH_SYN | TH_ACK)) == (TH_SYN | TH_ACK) &&
|
|
tp->t_rxtshift >= 1) {
|
|
/*
|
|
* If this is a SYN-ACK retransmission (first),
|
|
* retry without AccECN option and just with ACE fields.
|
|
* From second retransmission onwards, we don't send any
|
|
* Accurate ECN state.
|
|
*/
|
|
return;
|
|
}
|
|
|
|
if (max_len < (TCPOLEN_ACCECN_EMPTY + 1 * TCPOLEN_ACCECN_COUNTER)) {
|
|
/* Can carry EMPTY option which can be used to test path in SYN-ACK packet */
|
|
if (flags & TH_SYN) {
|
|
*lp++ = htonl((TCPOPT_ACCECN1 << 24) | (len << 16) |
|
|
(TCPOPT_NOP << 8) | TCPOPT_NOP);
|
|
*optlen += len + 2; /* 2 NOPs */
|
|
TCP_LOG(tp, "add empty AccECN option, optlen=%u", *optlen);
|
|
}
|
|
} else if (max_len < (TCPOLEN_ACCECN_EMPTY + 2 * TCPOLEN_ACCECN_COUNTER)) {
|
|
/* Can carry one option */
|
|
len += 1 * TCPOLEN_ACCECN_COUNTER;
|
|
if (tp->ecn_flags & TE_ACO_ECT1) {
|
|
*lp++ = htonl((TCPOPT_ACCECN1 << 24) | (len << 16) | ((e1b >> 8) & 0xffff));
|
|
*lp++ = htonl(((e1b & 0xff) << 24) | (TCPOPT_NOP << 16) | (TCPOPT_NOP << 8) | TCPOPT_NOP);
|
|
} else {
|
|
*lp++ = htonl((TCPOPT_ACCECN0 << 24) | (len << 16) | ((e0b >> 8) & 0xffff));
|
|
*lp++ = htonl(((e0b & 0xff) << 24) | (TCPOPT_NOP << 16) | (TCPOPT_NOP << 8) | TCPOPT_NOP);
|
|
}
|
|
*optlen += len + 3; /* 3 NOPs */
|
|
TCP_LOG(tp, "add single counter for AccECN option, optlen=%u", *optlen);
|
|
} else if (max_len < (TCPOLEN_ACCECN_EMPTY + 3 * TCPOLEN_ACCECN_COUNTER)) {
|
|
/* Can carry two options */
|
|
len += 2 * TCPOLEN_ACCECN_COUNTER;
|
|
if (tp->ecn_flags & TE_ACO_ECT1) {
|
|
*lp++ = htonl((TCPOPT_ACCECN1 << 24) | (len << 16) | ((e1b >> 8) & 0xffff));
|
|
*lp++ = htonl(((e1b & 0xff) << 24) | (ceb & 0xffffff));
|
|
} else {
|
|
*lp++ = htonl((TCPOPT_ACCECN0 << 24) | (len << 16) | ((e0b >> 8) & 0xffff));
|
|
*lp++ = htonl(((e0b & 0xff) << 24) | (ceb & 0xffffff));
|
|
}
|
|
*optlen += len; /* 0 NOPs */
|
|
TCP_LOG(tp, "add 2 counters for AccECN option, optlen=%u", *optlen);
|
|
} else {
|
|
/*
|
|
* TCP option sufficient to hold full AccECN option
|
|
* but send counter that changed during the entire connection.
|
|
*/
|
|
len += 3 * TCPOLEN_ACCECN_COUNTER;
|
|
/* Can carry all three options */
|
|
if (tp->ecn_flags & TE_ACO_ECT1) {
|
|
*lp++ = htonl((TCPOPT_ACCECN1 << 24) | (len << 16) | ((e1b >> 8) & 0xffff));
|
|
*lp++ = htonl(((e1b & 0xff) << 24) | (ceb & 0xffffff));
|
|
*lp++ = htonl(((e0b & 0xffffff) << 8) | TCPOPT_NOP);
|
|
} else {
|
|
*lp++ = htonl((TCPOPT_ACCECN0 << 24) | (len << 16) | ((e0b >> 8) & 0xffff));
|
|
*lp++ = htonl(((e0b & 0xff) << 24) | (ceb & 0xffffff));
|
|
*lp++ = htonl(((e1b & 0xffffff) << 8) | TCPOPT_NOP);
|
|
}
|
|
*optlen += len + 1; /* 1 NOP */
|
|
TCP_LOG(tp, "add all 3 counters for AccECN option, optlen=%u", *optlen);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Tcp output routine: figure out what should be sent and send it.
|
|
*
|
|
* Returns: 0 Success
|
|
* EADDRNOTAVAIL
|
|
* ENOBUFS
|
|
* EMSGSIZE
|
|
* EHOSTUNREACH
|
|
* ENETDOWN
|
|
* ip_output_list:ENOMEM
|
|
* ip_output_list:EADDRNOTAVAIL
|
|
* ip_output_list:ENETUNREACH
|
|
* ip_output_list:EHOSTUNREACH
|
|
* ip_output_list:EACCES
|
|
* ip_output_list:EMSGSIZE
|
|
* ip_output_list:ENOBUFS
|
|
* ip_output_list:??? [ignorable: mostly IPSEC/firewall/DLIL]
|
|
* ip6_output_list:EINVAL
|
|
* ip6_output_list:EOPNOTSUPP
|
|
* ip6_output_list:EHOSTUNREACH
|
|
* ip6_output_list:EADDRNOTAVAIL
|
|
* ip6_output_list:ENETUNREACH
|
|
* ip6_output_list:EMSGSIZE
|
|
* ip6_output_list:ENOBUFS
|
|
* ip6_output_list:??? [ignorable: mostly IPSEC/firewall/DLIL]
|
|
*/
|
|
int
|
|
tcp_output(struct tcpcb *tp)
|
|
{
|
|
struct inpcb *inp = tp->t_inpcb;
|
|
struct socket *so = inp->inp_socket;
|
|
int32_t len, recwin, sendwin, off;
|
|
uint32_t max_len = 0;
|
|
uint16_t flags;
|
|
int error;
|
|
struct mbuf *m;
|
|
struct ip *ip = NULL;
|
|
struct ip6_hdr *ip6 = NULL;
|
|
struct tcphdr *th;
|
|
u_char opt[TCP_MAXOLEN];
|
|
unsigned int ipoptlen, optlen, hdrlen;
|
|
int idle, sendalot, lost = 0;
|
|
int sendalot_cnt = 0;
|
|
int i, sack_rxmit;
|
|
int tso = 0;
|
|
int sack_bytes_rxmt;
|
|
tcp_seq old_snd_nxt = 0;
|
|
struct sackhole *p;
|
|
#if IPSEC
|
|
size_t ipsec_optlen = 0;
|
|
#endif /* IPSEC */
|
|
int idle_time = 0;
|
|
struct mbuf *packetlist = NULL;
|
|
struct mbuf *tp_inp_options = inp->inp_depend4.inp4_options;
|
|
int isipv6 = inp->inp_vflag & INP_IPV6;
|
|
int packchain_listadd = 0;
|
|
int so_options = so->so_options;
|
|
struct rtentry *rt;
|
|
u_int32_t svc_flags = 0, allocated_len;
|
|
#if MPTCP
|
|
boolean_t mptcp_acknow;
|
|
#endif /* MPTCP */
|
|
boolean_t cell = FALSE;
|
|
boolean_t wifi = FALSE;
|
|
boolean_t wired = FALSE;
|
|
boolean_t sack_rescue_rxt = FALSE;
|
|
int sotc = so->so_traffic_class;
|
|
boolean_t do_not_compress = FALSE;
|
|
boolean_t sack_rxmted = FALSE;
|
|
|
|
/*
|
|
* Determine length of data that should be transmitted,
|
|
* and flags that will be used.
|
|
* If there is some data or critical controls (SYN, RST)
|
|
* to send, then transmit; otherwise, investigate further.
|
|
*/
|
|
idle = (tp->t_flags & TF_LASTIDLE) || (tp->snd_max == tp->snd_una);
|
|
|
|
/* Since idle_time is signed integer, the following integer subtraction
|
|
* will take care of wrap around of tcp_now
|
|
*/
|
|
idle_time = tcp_now - tp->t_rcvtime;
|
|
if (idle && idle_time >= TCP_IDLETIMEOUT(tp)) {
|
|
if (CC_ALGO(tp)->after_idle != NULL &&
|
|
(tp->tcp_cc_index != TCP_CC_ALGO_CUBIC_INDEX ||
|
|
idle_time >= TCP_CC_CWND_NONVALIDATED_PERIOD)) {
|
|
CC_ALGO(tp)->after_idle(tp);
|
|
tcp_ccdbg_trace(tp, NULL, TCP_CC_IDLE_TIMEOUT);
|
|
}
|
|
|
|
/*
|
|
* Do some other tasks that need to be done after
|
|
* idle time
|
|
*/
|
|
if (!SLIST_EMPTY(&tp->t_rxt_segments)) {
|
|
tcp_rxtseg_clean(tp);
|
|
}
|
|
|
|
/* If stretch ack was auto-disabled, re-evaluate it */
|
|
tcp_cc_after_idle_stretchack(tp);
|
|
tp->t_forced_acks = TCP_FORCED_ACKS_COUNT;
|
|
}
|
|
tp->t_flags &= ~TF_LASTIDLE;
|
|
if (idle) {
|
|
if (tp->t_flags & TF_MORETOCOME) {
|
|
tp->t_flags |= TF_LASTIDLE;
|
|
idle = 0;
|
|
}
|
|
}
|
|
#if MPTCP
|
|
if (tp->t_mpflags & TMPF_RESET) {
|
|
tcp_check_timer_state(tp);
|
|
/*
|
|
* Once a RST has been sent for an MPTCP subflow,
|
|
* the subflow socket stays around until deleted.
|
|
* No packets such as FINs must be sent after RST.
|
|
*/
|
|
return 0;
|
|
}
|
|
#endif /* MPTCP */
|
|
|
|
again:
|
|
#if MPTCP
|
|
mptcp_acknow = FALSE;
|
|
|
|
if (so->so_flags & SOF_MP_SUBFLOW && SEQ_LT(tp->snd_nxt, tp->snd_una)) {
|
|
os_log_error(mptcp_log_handle, "%s - %lx: snd_nxt is %u and snd_una is %u, cnt %d\n",
|
|
__func__, (unsigned long)VM_KERNEL_ADDRPERM(tp->t_mpsub->mpts_mpte),
|
|
tp->snd_nxt, tp->snd_una, sendalot_cnt);
|
|
}
|
|
#endif
|
|
do_not_compress = FALSE;
|
|
sendalot_cnt++;
|
|
|
|
KERNEL_DEBUG(DBG_FNC_TCP_OUTPUT | DBG_FUNC_START, 0, 0, 0, 0, 0);
|
|
|
|
if (isipv6) {
|
|
KERNEL_DEBUG(DBG_LAYER_BEG,
|
|
((inp->inp_fport << 16) | inp->inp_lport),
|
|
(((inp->in6p_laddr.s6_addr16[0] & 0xffff) << 16) |
|
|
(inp->in6p_faddr.s6_addr16[0] & 0xffff)),
|
|
sendalot, 0, 0);
|
|
} else {
|
|
KERNEL_DEBUG(DBG_LAYER_BEG,
|
|
((inp->inp_fport << 16) | inp->inp_lport),
|
|
(((inp->inp_laddr.s_addr & 0xffff) << 16) |
|
|
(inp->inp_faddr.s_addr & 0xffff)),
|
|
sendalot, 0, 0);
|
|
}
|
|
/*
|
|
* If the route generation id changed, we need to check that our
|
|
* local (source) IP address is still valid. If it isn't either
|
|
* return error or silently do nothing (assuming the address will
|
|
* come back before the TCP connection times out).
|
|
*/
|
|
rt = inp->inp_route.ro_rt;
|
|
if (rt != NULL && ROUTE_UNUSABLE(&tp->t_inpcb->inp_route)) {
|
|
struct ifnet *ifp;
|
|
struct in_ifaddr *ia = NULL;
|
|
struct in6_ifaddr *ia6 = NULL;
|
|
int found_srcaddr = 0;
|
|
|
|
/* disable multipages at the socket */
|
|
somultipages(so, FALSE);
|
|
|
|
/* Disable TSO for the socket until we know more */
|
|
tp->t_flags &= ~TF_TSO;
|
|
|
|
soif2kcl(so, FALSE);
|
|
|
|
if (isipv6) {
|
|
ia6 = ifa_foraddr6(&inp->in6p_laddr);
|
|
if (ia6 != NULL) {
|
|
found_srcaddr = 1;
|
|
}
|
|
} else {
|
|
ia = ifa_foraddr(inp->inp_laddr.s_addr);
|
|
if (ia != NULL) {
|
|
found_srcaddr = 1;
|
|
}
|
|
}
|
|
|
|
/* check that the source address is still valid */
|
|
if (found_srcaddr == 0) {
|
|
soevent(so,
|
|
(SO_FILT_HINT_LOCKED | SO_FILT_HINT_NOSRCADDR));
|
|
|
|
if (tp->t_state >= TCPS_CLOSE_WAIT) {
|
|
tcp_drop(tp, EADDRNOTAVAIL);
|
|
return EADDRNOTAVAIL;
|
|
}
|
|
|
|
/*
|
|
* Set retransmit timer if it wasn't set,
|
|
* reset Persist timer and shift register as the
|
|
* advertised peer window may not be valid anymore
|
|
*/
|
|
if (tp->t_timer[TCPT_REXMT] == 0) {
|
|
tp->t_timer[TCPT_REXMT] =
|
|
OFFSET_FROM_START(tp, tp->t_rxtcur);
|
|
if (tp->t_timer[TCPT_PERSIST] != 0) {
|
|
tp->t_timer[TCPT_PERSIST] = 0;
|
|
tp->t_persist_stop = 0;
|
|
TCP_RESET_REXMT_STATE(tp);
|
|
}
|
|
}
|
|
|
|
if (tp->t_pktlist_head != NULL) {
|
|
m_freem_list(tp->t_pktlist_head);
|
|
}
|
|
TCP_PKTLIST_CLEAR(tp);
|
|
|
|
/* drop connection if source address isn't available */
|
|
if (so->so_flags & SOF_NOADDRAVAIL) {
|
|
tcp_drop(tp, EADDRNOTAVAIL);
|
|
return EADDRNOTAVAIL;
|
|
} else {
|
|
TCP_LOG_OUTPUT(tp, "no source address silently ignored");
|
|
tcp_check_timer_state(tp);
|
|
return 0; /* silently ignore, keep data in socket: address may be back */
|
|
}
|
|
}
|
|
if (ia != NULL) {
|
|
ifa_remref(&ia->ia_ifa);
|
|
}
|
|
|
|
if (ia6 != NULL) {
|
|
ifa_remref(&ia6->ia_ifa);
|
|
}
|
|
|
|
/*
|
|
* Address is still valid; check for multipages capability
|
|
* again in case the outgoing interface has changed.
|
|
*/
|
|
RT_LOCK(rt);
|
|
if ((ifp = rt->rt_ifp) != NULL) {
|
|
somultipages(so, (ifp->if_hwassist & IFNET_MULTIPAGES));
|
|
tcp_set_tso(tp, ifp);
|
|
soif2kcl(so, (ifp->if_eflags & IFEF_2KCL));
|
|
tcp_set_ecn(tp, ifp);
|
|
}
|
|
if (rt->rt_flags & RTF_UP) {
|
|
RT_GENID_SYNC(rt);
|
|
}
|
|
/*
|
|
* See if we should do MTU discovery. Don't do it if:
|
|
* 1) it is disabled via the sysctl
|
|
* 2) the route isn't up
|
|
* 3) the MTU is locked (if it is, then discovery
|
|
* has been disabled)
|
|
*/
|
|
|
|
if (!path_mtu_discovery || ((rt != NULL) &&
|
|
(!(rt->rt_flags & RTF_UP) ||
|
|
(rt->rt_rmx.rmx_locks & RTV_MTU)))) {
|
|
tp->t_flags &= ~TF_PMTUD;
|
|
} else {
|
|
tp->t_flags |= TF_PMTUD;
|
|
}
|
|
|
|
RT_UNLOCK(rt);
|
|
}
|
|
|
|
if (rt != NULL) {
|
|
cell = IFNET_IS_CELLULAR(rt->rt_ifp);
|
|
wifi = (!cell && IFNET_IS_WIFI(rt->rt_ifp));
|
|
wired = (!wifi && IFNET_IS_WIRED(rt->rt_ifp));
|
|
}
|
|
|
|
/*
|
|
* If we've recently taken a timeout, snd_max will be greater than
|
|
* snd_nxt. There may be SACK information that allows us to avoid
|
|
* resending already delivered data. Adjust snd_nxt accordingly.
|
|
*/
|
|
if (SACK_ENABLED(tp) && SEQ_LT(tp->snd_nxt, tp->snd_max)) {
|
|
max_len = tcp_sack_adjust(tp);
|
|
}
|
|
sendalot = 0;
|
|
off = tp->snd_nxt - tp->snd_una;
|
|
sendwin = min(tp->snd_wnd, tp->snd_cwnd);
|
|
|
|
if (tp->t_flags & TF_SLOWLINK && slowlink_wsize > 0) {
|
|
sendwin = min(sendwin, slowlink_wsize);
|
|
}
|
|
|
|
flags = tcp_outflags[tp->t_state];
|
|
/*
|
|
* Send any SACK-generated retransmissions. If we're explicitly
|
|
* trying to send out new data (when sendalot is 1), bypass this
|
|
* function. If we retransmit in fast recovery mode, decrement
|
|
* snd_cwnd, since we're replacing a (future) new transmission
|
|
* with a retransmission now, and we previously incremented
|
|
* snd_cwnd in tcp_input().
|
|
*/
|
|
/*
|
|
* Still in sack recovery , reset rxmit flag to zero.
|
|
*/
|
|
sack_rxmit = 0;
|
|
sack_bytes_rxmt = 0;
|
|
len = 0;
|
|
p = NULL;
|
|
if (SACK_ENABLED(tp) && IN_FASTRECOVERY(tp) &&
|
|
(p = tcp_sack_output(tp, &sack_bytes_rxmt))) {
|
|
int32_t cwin;
|
|
|
|
if (tcp_do_better_lr) {
|
|
cwin = min(tp->snd_wnd, tp->snd_cwnd) - tcp_flight_size(tp);
|
|
if (cwin <= 0 && sack_rxmted == FALSE) {
|
|
/* Allow to clock out at least on per period */
|
|
cwin = tp->t_maxseg;
|
|
}
|
|
|
|
sack_rxmted = TRUE;
|
|
} else {
|
|
cwin = min(tp->snd_wnd, tp->snd_cwnd) - sack_bytes_rxmt;
|
|
}
|
|
if (cwin < 0) {
|
|
cwin = 0;
|
|
}
|
|
/* Do not retransmit SACK segments beyond snd_recover */
|
|
if (SEQ_GT(p->end, tp->snd_recover)) {
|
|
/*
|
|
* (At least) part of sack hole extends beyond
|
|
* snd_recover. Check to see if we can rexmit data
|
|
* for this hole.
|
|
*/
|
|
if (SEQ_GEQ(p->rxmit, tp->snd_recover)) {
|
|
/*
|
|
* Can't rexmit any more data for this hole.
|
|
* That data will be rexmitted in the next
|
|
* sack recovery episode, when snd_recover
|
|
* moves past p->rxmit.
|
|
*/
|
|
p = NULL;
|
|
goto after_sack_rexmit;
|
|
} else {
|
|
/* Can rexmit part of the current hole */
|
|
len = ((int32_t)min(cwin,
|
|
tp->snd_recover - p->rxmit));
|
|
}
|
|
} else {
|
|
len = ((int32_t)min(cwin, p->end - p->rxmit));
|
|
}
|
|
if (len > 0) {
|
|
off = p->rxmit - tp->snd_una;
|
|
sack_rxmit = 1;
|
|
sendalot = 1;
|
|
/* Everything sent after snd_nxt will allow us to account for fast-retransmit of the retransmitted segment */
|
|
tp->send_highest_sack = tp->snd_nxt;
|
|
tp->t_new_dupacks = 0;
|
|
tcpstat.tcps_sack_rexmits++;
|
|
tcpstat.tcps_sack_rexmit_bytes +=
|
|
min(len, tp->t_maxseg);
|
|
} else {
|
|
len = 0;
|
|
}
|
|
}
|
|
after_sack_rexmit:
|
|
/*
|
|
* Get standard flags, and add SYN or FIN if requested by 'hidden'
|
|
* state flags.
|
|
*/
|
|
if (tp->t_flags & TF_NEEDFIN) {
|
|
flags |= TH_FIN;
|
|
}
|
|
|
|
/*
|
|
* If in persist timeout with window of 0, send 1 byte.
|
|
* Otherwise, if window is small but nonzero
|
|
* and timer expired, we will send what we can
|
|
* and go to transmit state.
|
|
*/
|
|
if (tp->t_flagsext & TF_FORCE) {
|
|
if (sendwin == 0) {
|
|
/*
|
|
* If we still have some data to send, then
|
|
* clear the FIN bit. Usually this would
|
|
* happen below when it realizes that we
|
|
* aren't sending all the data. However,
|
|
* if we have exactly 1 byte of unsent data,
|
|
* then it won't clear the FIN bit below,
|
|
* and if we are in persist state, we wind
|
|
* up sending the packet without recording
|
|
* that we sent the FIN bit.
|
|
*
|
|
* We can't just blindly clear the FIN bit,
|
|
* because if we don't have any more data
|
|
* to send then the probe will be the FIN
|
|
* itself.
|
|
*/
|
|
if (off < so->so_snd.sb_cc) {
|
|
flags &= ~TH_FIN;
|
|
}
|
|
sendwin = 1;
|
|
} else {
|
|
tp->t_timer[TCPT_PERSIST] = 0;
|
|
tp->t_persist_stop = 0;
|
|
TCP_RESET_REXMT_STATE(tp);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* If snd_nxt == snd_max and we have transmitted a FIN, the
|
|
* offset will be > 0 even if so_snd.sb_cc is 0, resulting in
|
|
* a negative length. This can also occur when TCP opens up
|
|
* its congestion window while receiving additional duplicate
|
|
* acks after fast-retransmit because TCP will reset snd_nxt
|
|
* to snd_max after the fast-retransmit.
|
|
*
|
|
* In the normal retransmit-FIN-only case, however, snd_nxt will
|
|
* be set to snd_una, the offset will be 0, and the length may
|
|
* wind up 0.
|
|
*
|
|
* If sack_rxmit is true we are retransmitting from the scoreboard
|
|
* in which case len is already set.
|
|
*/
|
|
if (sack_rxmit == 0) {
|
|
if (sack_bytes_rxmt == 0) {
|
|
len = min(so->so_snd.sb_cc, sendwin) - off;
|
|
} else {
|
|
int32_t cwin;
|
|
|
|
if (tcp_do_better_lr) {
|
|
cwin = tp->snd_cwnd - tcp_flight_size(tp);
|
|
} else {
|
|
cwin = tp->snd_cwnd -
|
|
(tp->snd_nxt - tp->sack_newdata) -
|
|
sack_bytes_rxmt;
|
|
}
|
|
if (cwin < 0) {
|
|
cwin = 0;
|
|
}
|
|
/*
|
|
* We are inside of a SACK recovery episode and are
|
|
* sending new data, having retransmitted all the
|
|
* data possible in the scoreboard.
|
|
*/
|
|
len = min(so->so_snd.sb_cc, tp->snd_wnd) - off;
|
|
/*
|
|
* Don't remove this (len > 0) check !
|
|
* We explicitly check for len > 0 here (although it
|
|
* isn't really necessary), to work around a gcc
|
|
* optimization issue - to force gcc to compute
|
|
* len above. Without this check, the computation
|
|
* of len is bungled by the optimizer.
|
|
*/
|
|
if (len > 0) {
|
|
len = imin(len, cwin);
|
|
} else {
|
|
len = 0;
|
|
}
|
|
/*
|
|
* At this point SACK recovery can not send any
|
|
* data from scoreboard or any new data. Check
|
|
* if we can do a rescue retransmit towards the
|
|
* tail end of recovery window.
|
|
*/
|
|
if (len == 0 && cwin > 0 &&
|
|
SEQ_LT(tp->snd_fack, tp->snd_recover) &&
|
|
!(tp->t_flagsext & TF_RESCUE_RXT)) {
|
|
len = min((tp->snd_recover - tp->snd_fack),
|
|
tp->t_maxseg);
|
|
len = imin(len, cwin);
|
|
old_snd_nxt = tp->snd_nxt;
|
|
sack_rescue_rxt = TRUE;
|
|
tp->snd_nxt = tp->snd_recover - len;
|
|
/*
|
|
* If FIN has been sent, snd_max
|
|
* must have been advanced to cover it.
|
|
*/
|
|
if ((tp->t_flags & TF_SENTFIN) &&
|
|
tp->snd_max == tp->snd_recover) {
|
|
tp->snd_nxt--;
|
|
}
|
|
|
|
off = tp->snd_nxt - tp->snd_una;
|
|
sendalot = 0;
|
|
tp->t_flagsext |= TF_RESCUE_RXT;
|
|
}
|
|
}
|
|
}
|
|
|
|
if (max_len != 0 && len > 0) {
|
|
len = min(len, max_len);
|
|
}
|
|
|
|
/*
|
|
* Lop off SYN bit if it has already been sent. However, if this
|
|
* is SYN-SENT state and if segment contains data and if we don't
|
|
* know that foreign host supports TAO, suppress sending segment.
|
|
*/
|
|
if ((flags & TH_SYN) && SEQ_GT(tp->snd_nxt, tp->snd_una)) {
|
|
if (tp->t_state == TCPS_SYN_RECEIVED && tfo_enabled(tp) && tp->snd_nxt == tp->snd_una + 1) {
|
|
/* We are sending the SYN again! */
|
|
off--;
|
|
len++;
|
|
} else {
|
|
if (tp->t_state != TCPS_SYN_RECEIVED || tfo_enabled(tp)) {
|
|
flags &= ~TH_SYN;
|
|
}
|
|
|
|
off--;
|
|
len++;
|
|
if (len > 0 && tp->t_state == TCPS_SYN_SENT) {
|
|
while (inp->inp_sndinprog_cnt == 0 &&
|
|
tp->t_pktlist_head != NULL) {
|
|
packetlist = tp->t_pktlist_head;
|
|
packchain_listadd = tp->t_lastchain;
|
|
packchain_sent++;
|
|
TCP_PKTLIST_CLEAR(tp);
|
|
|
|
error = tcp_ip_output(so, tp, packetlist,
|
|
packchain_listadd, tp_inp_options,
|
|
(so_options & SO_DONTROUTE),
|
|
(sack_rxmit || (sack_bytes_rxmt != 0)),
|
|
isipv6);
|
|
}
|
|
|
|
/*
|
|
* tcp was closed while we were in ip,
|
|
* resume close
|
|
*/
|
|
if (inp->inp_sndinprog_cnt == 0 &&
|
|
(tp->t_flags & TF_CLOSING)) {
|
|
tp->t_flags &= ~TF_CLOSING;
|
|
(void) tcp_close(tp);
|
|
} else {
|
|
tcp_check_timer_state(tp);
|
|
}
|
|
KERNEL_DEBUG(DBG_FNC_TCP_OUTPUT | DBG_FUNC_END,
|
|
0, 0, 0, 0, 0);
|
|
return 0;
|
|
}
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Be careful not to send data and/or FIN on SYN segments.
|
|
* This measure is needed to prevent interoperability problems
|
|
* with not fully conformant TCP implementations.
|
|
*
|
|
* In case of TFO, we handle the setting of the len in
|
|
* tcp_tfo_check. In case TFO is not enabled, never ever send
|
|
* SYN+data.
|
|
*/
|
|
if ((flags & TH_SYN) && !tfo_enabled(tp)) {
|
|
len = 0;
|
|
flags &= ~TH_FIN;
|
|
}
|
|
|
|
/*
|
|
* Don't send a RST with data.
|
|
*/
|
|
if (flags & TH_RST) {
|
|
len = 0;
|
|
}
|
|
|
|
if ((flags & TH_SYN) && tp->t_state <= TCPS_SYN_SENT && tfo_enabled(tp)) {
|
|
len = tcp_tfo_check(tp, len);
|
|
}
|
|
|
|
/*
|
|
* The check here used to be (len < 0). Some times len is zero
|
|
* when the congestion window is closed and we need to check
|
|
* if persist timer has to be set in that case. But don't set
|
|
* persist until connection is established.
|
|
*/
|
|
if (len <= 0 && !(flags & TH_SYN)) {
|
|
/*
|
|
* If FIN has been sent but not acked,
|
|
* but we haven't been called to retransmit,
|
|
* len will be < 0. Otherwise, window shrank
|
|
* after we sent into it. If window shrank to 0,
|
|
* cancel pending retransmit, pull snd_nxt back
|
|
* to (closed) window, and set the persist timer
|
|
* if it isn't already going. If the window didn't
|
|
* close completely, just wait for an ACK.
|
|
*/
|
|
len = 0;
|
|
if (sendwin == 0) {
|
|
tp->t_timer[TCPT_REXMT] = 0;
|
|
tp->t_timer[TCPT_PTO] = 0;
|
|
TCP_RESET_REXMT_STATE(tp);
|
|
tp->snd_nxt = tp->snd_una;
|
|
off = 0;
|
|
if (tp->t_timer[TCPT_PERSIST] == 0) {
|
|
tcp_setpersist(tp);
|
|
}
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Automatic sizing of send socket buffer. Increase the send
|
|
* socket buffer size if all of the following criteria are met
|
|
* 1. the receiver has enough buffer space for this data
|
|
* 2. send buffer is filled to 7/8th with data (so we actually
|
|
* have data to make use of it);
|
|
* 3. our send window (slow start and congestion controlled) is
|
|
* larger than sent but unacknowledged data in send buffer.
|
|
*/
|
|
if (!INP_WAIT_FOR_IF_FEEDBACK(inp) && !IN_FASTRECOVERY(tp) &&
|
|
(so->so_snd.sb_flags & (SB_AUTOSIZE | SB_TRIM)) == SB_AUTOSIZE) {
|
|
if ((tp->snd_wnd / 4 * 5) >= so->so_snd.sb_hiwat &&
|
|
so->so_snd.sb_cc >= (so->so_snd.sb_hiwat / 8 * 7) &&
|
|
sendwin >= (so->so_snd.sb_cc - (tp->snd_nxt - tp->snd_una))) {
|
|
if (sbreserve(&so->so_snd,
|
|
min(so->so_snd.sb_hiwat + tcp_autosndbuf_inc,
|
|
tcp_autosndbuf_max)) == 1) {
|
|
so->so_snd.sb_idealsize = so->so_snd.sb_hiwat;
|
|
}
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Truncate to the maximum segment length or enable TCP Segmentation
|
|
* Offloading (if supported by hardware) and ensure that FIN is removed
|
|
* if the length no longer contains the last data byte.
|
|
*
|
|
* TSO may only be used if we are in a pure bulk sending state.
|
|
* The presence of TCP-MD5, SACK retransmits, SACK advertizements,
|
|
* filters and IP options, as well as disabling hardware checksum
|
|
* offload prevent using TSO. With TSO the TCP header is the same
|
|
* (except for the sequence number) for all generated packets. This
|
|
* makes it impossible to transmit any options which vary per generated
|
|
* segment or packet.
|
|
*
|
|
* The length of TSO bursts is limited to TCP_MAXWIN. That limit and
|
|
* removal of FIN (if not already catched here) are handled later after
|
|
* the exact length of the TCP options are known.
|
|
*/
|
|
#if IPSEC
|
|
/*
|
|
* Pre-calculate here as we save another lookup into the darknesses
|
|
* of IPsec that way and can actually decide if TSO is ok.
|
|
*/
|
|
if (ipsec_bypass == 0) {
|
|
ipsec_optlen = ipsec_hdrsiz_tcp(tp);
|
|
}
|
|
#endif
|
|
if (len > tp->t_maxseg) {
|
|
if ((tp->t_flags & TF_TSO) && tcp_do_tso && hwcksum_tx &&
|
|
kipf_count == 0 &&
|
|
tp->rcv_numsacks == 0 && sack_rxmit == 0 &&
|
|
sack_bytes_rxmt == 0 &&
|
|
inp->inp_options == NULL &&
|
|
inp->in6p_options == NULL
|
|
#if IPSEC
|
|
&& ipsec_optlen == 0
|
|
#endif
|
|
) {
|
|
tso = 1;
|
|
sendalot = 0;
|
|
} else {
|
|
len = tp->t_maxseg;
|
|
sendalot = 1;
|
|
tso = 0;
|
|
}
|
|
} else {
|
|
tso = 0;
|
|
}
|
|
|
|
/* Send one segment or less as a tail loss probe */
|
|
if (tp->t_flagsext & TF_SENT_TLPROBE) {
|
|
len = min(len, tp->t_maxseg);
|
|
sendalot = 0;
|
|
tso = 0;
|
|
}
|
|
|
|
#if MPTCP
|
|
if (so->so_flags & SOF_MP_SUBFLOW && off < 0) {
|
|
os_log_error(mptcp_log_handle, "%s - %lx: offset is negative! len %d off %d\n",
|
|
__func__, (unsigned long)VM_KERNEL_ADDRPERM(tp->t_mpsub->mpts_mpte),
|
|
len, off);
|
|
}
|
|
|
|
if ((so->so_flags & SOF_MP_SUBFLOW) &&
|
|
!(tp->t_mpflags & TMPF_TCP_FALLBACK)) {
|
|
int newlen = len;
|
|
struct mptcb *mp_tp = tptomptp(tp);
|
|
if (tp->t_state >= TCPS_ESTABLISHED &&
|
|
(tp->t_mpflags & TMPF_SND_MPPRIO ||
|
|
tp->t_mpflags & TMPF_SND_REM_ADDR ||
|
|
tp->t_mpflags & TMPF_SND_MPFAIL ||
|
|
(tp->t_mpflags & TMPF_SND_KEYS &&
|
|
mp_tp->mpt_version == MPTCP_VERSION_0) ||
|
|
tp->t_mpflags & TMPF_SND_JACK ||
|
|
tp->t_mpflags & TMPF_MPTCP_ECHO_ADDR)) {
|
|
if (len > 0) {
|
|
len = 0;
|
|
tso = 0;
|
|
}
|
|
/*
|
|
* On a new subflow, don't try to send again, because
|
|
* we are still waiting for the fourth ack.
|
|
*/
|
|
if (!(tp->t_mpflags & TMPF_PREESTABLISHED)) {
|
|
sendalot = 1;
|
|
}
|
|
mptcp_acknow = TRUE;
|
|
} else {
|
|
mptcp_acknow = FALSE;
|
|
}
|
|
/*
|
|
* The contiguous bytes in the subflow socket buffer can be
|
|
* discontiguous at the MPTCP level. Since only one DSS
|
|
* option can be sent in one packet, reduce length to match
|
|
* the contiguous MPTCP level. Set sendalot to send remainder.
|
|
*/
|
|
if (len > 0 && off >= 0) {
|
|
newlen = mptcp_adj_sendlen(so, off);
|
|
}
|
|
|
|
if (newlen < len) {
|
|
len = newlen;
|
|
if (len <= tp->t_maxseg) {
|
|
tso = 0;
|
|
}
|
|
}
|
|
}
|
|
#endif /* MPTCP */
|
|
|
|
if (sack_rxmit) {
|
|
if (SEQ_LT(p->rxmit + len, tp->snd_una + so->so_snd.sb_cc)) {
|
|
flags &= ~TH_FIN;
|
|
}
|
|
} else {
|
|
if (SEQ_LT(tp->snd_nxt + len, tp->snd_una + so->so_snd.sb_cc)) {
|
|
flags &= ~TH_FIN;
|
|
}
|
|
}
|
|
/*
|
|
* Compare available window to amount of window
|
|
* known to peer (as advertised window less
|
|
* next expected input). If the difference is at least two
|
|
* max size segments, or at least 25% of the maximum possible
|
|
* window, then want to send a window update to peer.
|
|
*/
|
|
recwin = tcp_sbspace(tp);
|
|
|
|
if (!(so->so_flags & SOF_MP_SUBFLOW)) {
|
|
if (recwin < (int32_t)(so->so_rcv.sb_hiwat / 4) &&
|
|
recwin < (int)tp->t_maxseg) {
|
|
recwin = 0;
|
|
}
|
|
} else {
|
|
struct mptcb *mp_tp = tptomptp(tp);
|
|
struct socket *mp_so = mptetoso(mp_tp->mpt_mpte);
|
|
|
|
if (recwin < (int32_t)(mp_so->so_rcv.sb_hiwat / 4) &&
|
|
recwin < (int)tp->t_maxseg) {
|
|
recwin = 0;
|
|
}
|
|
}
|
|
|
|
#if TRAFFIC_MGT
|
|
if (tcp_recv_bg == 1 || IS_TCP_RECV_BG(so)) {
|
|
/*
|
|
* Timestamp MUST be supported to use rledbat unless we haven't
|
|
* yet negotiated it.
|
|
*/
|
|
if (TCP_RLEDBAT_ENABLED(tp) || (tcp_rledbat && tp->t_state <
|
|
TCPS_ESTABLISHED)) {
|
|
if (recwin > 0 && tcp_cc_rledbat.get_rlwin != NULL) {
|
|
/* Min of flow control window and rledbat window */
|
|
recwin = imin(recwin, tcp_cc_rledbat.get_rlwin(tp));
|
|
}
|
|
} else if (recwin > 0 && tcp_recv_throttle(tp)) {
|
|
uint32_t min_iaj_win = tcp_min_iaj_win * tp->t_maxseg;
|
|
uint32_t bg_rwintop = tp->rcv_adv;
|
|
if (SEQ_LT(bg_rwintop, tp->rcv_nxt + min_iaj_win)) {
|
|
bg_rwintop = tp->rcv_nxt + min_iaj_win;
|
|
}
|
|
recwin = imin((int32_t)(bg_rwintop - tp->rcv_nxt),
|
|
recwin);
|
|
if (recwin < 0) {
|
|
recwin = 0;
|
|
}
|
|
}
|
|
}
|
|
#endif /* TRAFFIC_MGT */
|
|
|
|
if (recwin > (int32_t)(TCP_MAXWIN << tp->rcv_scale)) {
|
|
recwin = (int32_t)(TCP_MAXWIN << tp->rcv_scale);
|
|
}
|
|
|
|
if (!(so->so_flags & SOF_MP_SUBFLOW)) {
|
|
if (recwin < (int32_t)(tp->rcv_adv - tp->rcv_nxt)) {
|
|
recwin = (int32_t)(tp->rcv_adv - tp->rcv_nxt);
|
|
}
|
|
} else {
|
|
struct mptcb *mp_tp = tptomptp(tp);
|
|
int64_t recwin_announced = (int64_t)(mp_tp->mpt_rcvadv - mp_tp->mpt_rcvnxt);
|
|
|
|
/* Don't remove what we announced at the MPTCP-layer */
|
|
VERIFY(recwin_announced < INT32_MAX && recwin_announced > INT32_MIN);
|
|
if (recwin < (int32_t)recwin_announced) {
|
|
recwin = (int32_t)recwin_announced;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Sender silly window avoidance. We transmit under the following
|
|
* conditions when len is non-zero:
|
|
*
|
|
* - we've timed out (e.g. persist timer)
|
|
* - we need to retransmit
|
|
* - We have a full segment (or more with TSO)
|
|
* - This is the last buffer in a write()/send() and we are
|
|
* either idle or running NODELAY
|
|
* - we have more then 1/2 the maximum send window's worth of
|
|
* data (receiver may be limited the window size)
|
|
*/
|
|
if (len) {
|
|
if (tp->t_flagsext & TF_FORCE) {
|
|
goto send;
|
|
}
|
|
if (SEQ_LT(tp->snd_nxt, tp->snd_max)) {
|
|
goto send;
|
|
}
|
|
if (sack_rxmit) {
|
|
goto send;
|
|
}
|
|
|
|
/*
|
|
* If this here is the first segment after SYN/ACK and TFO
|
|
* is being used, then we always send it, regardless of Nagle,...
|
|
*/
|
|
if (tp->t_state == TCPS_SYN_RECEIVED &&
|
|
tfo_enabled(tp) &&
|
|
(tp->t_tfo_flags & TFO_F_COOKIE_VALID) &&
|
|
tp->snd_nxt == tp->iss + 1) {
|
|
goto send;
|
|
}
|
|
|
|
/*
|
|
* Send new data on the connection only if it is
|
|
* not flow controlled
|
|
*/
|
|
if (!INP_WAIT_FOR_IF_FEEDBACK(inp) ||
|
|
tp->t_state != TCPS_ESTABLISHED) {
|
|
if (off + len == tp->snd_wnd) {
|
|
/* We are limited by the receiver's window... */
|
|
if (tp->t_rcvwnd_limited_start_time == 0) {
|
|
tp->t_rcvwnd_limited_start_time = net_uptime_us();
|
|
}
|
|
} else {
|
|
/* We are no more limited by the receiver's window... */
|
|
if (tp->t_rcvwnd_limited_start_time != 0) {
|
|
uint64_t now = net_uptime_us();
|
|
|
|
ASSERT(now >= tp->t_rcvwnd_limited_start_time);
|
|
|
|
tp->t_rcvwnd_limited_total_time += (now - tp->t_rcvwnd_limited_start_time);
|
|
|
|
tp->t_rcvwnd_limited_start_time = 0;
|
|
}
|
|
}
|
|
|
|
if (len >= tp->t_maxseg) {
|
|
goto send;
|
|
}
|
|
|
|
if (!(tp->t_flags & TF_MORETOCOME) &&
|
|
(idle || tp->t_flags & TF_NODELAY ||
|
|
(tp->t_flags & TF_MAXSEGSNT) ||
|
|
ALLOW_LIMITED_TRANSMIT(tp)) &&
|
|
(tp->t_flags & TF_NOPUSH) == 0 &&
|
|
(len + off >= so->so_snd.sb_cc ||
|
|
/*
|
|
* MPTCP needs to respect the DSS-mappings. So, it
|
|
* may be sending data that *could* have been
|
|
* coalesced, but cannot because of
|
|
* mptcp_adj_sendlen().
|
|
*/
|
|
so->so_flags & SOF_MP_SUBFLOW)) {
|
|
goto send;
|
|
}
|
|
if (len >= tp->max_sndwnd / 2 && tp->max_sndwnd > 0) {
|
|
goto send;
|
|
}
|
|
} else {
|
|
tcpstat.tcps_fcholdpacket++;
|
|
}
|
|
}
|
|
|
|
if (recwin > 0) {
|
|
/*
|
|
* "adv" is the amount we can increase the window,
|
|
* taking into account that we are limited by
|
|
* TCP_MAXWIN << tp->rcv_scale.
|
|
*/
|
|
int32_t adv, oldwin = 0;
|
|
adv = imin(recwin, (int)TCP_MAXWIN << tp->rcv_scale) -
|
|
(tp->rcv_adv - tp->rcv_nxt);
|
|
|
|
if (SEQ_GT(tp->rcv_adv, tp->rcv_nxt)) {
|
|
oldwin = tp->rcv_adv - tp->rcv_nxt;
|
|
}
|
|
|
|
if (tcp_ack_strategy == TCP_ACK_STRATEGY_LEGACY) {
|
|
if (adv >= (int32_t) (2 * tp->t_maxseg)) {
|
|
/*
|
|
* Update only if the resulting scaled value of
|
|
* the window changed, or if there is a change in
|
|
* the sequence since the last ack. This avoids
|
|
* what appears as dupe ACKS (see rdar://5640997)
|
|
*
|
|
* If streaming is detected avoid sending too many
|
|
* window updates. We will depend on the delack
|
|
* timer to send a window update when needed.
|
|
*
|
|
* If there is more data to read, don't send an ACK.
|
|
* Otherwise we will end up sending many ACKs if the
|
|
* application is doing micro-reads.
|
|
*/
|
|
if (!(tp->t_flags & TF_STRETCHACK) &&
|
|
(tp->last_ack_sent != tp->rcv_nxt ||
|
|
((oldwin + adv) >> tp->rcv_scale) >
|
|
(oldwin >> tp->rcv_scale))) {
|
|
goto send;
|
|
}
|
|
}
|
|
} else {
|
|
if (adv >= (int32_t) (2 * tp->t_maxseg)) {
|
|
/*
|
|
* ACK every second full-sized segment, if the
|
|
* ACK is advancing or the window becomes bigger
|
|
*/
|
|
if (so->so_rcv.sb_cc < so->so_rcv.sb_lowat &&
|
|
(tp->last_ack_sent != tp->rcv_nxt ||
|
|
((oldwin + adv) >> tp->rcv_scale) >
|
|
(oldwin >> tp->rcv_scale))) {
|
|
goto send;
|
|
}
|
|
} else if (tp->t_flags & TF_DELACK) {
|
|
/*
|
|
* If we delayed the ACK and the window
|
|
* is not advancing by a lot (< 2MSS), ACK
|
|
* immediately if the last incoming packet had
|
|
* the push flag set and we emptied the buffer.
|
|
*
|
|
* This takes care of a sender doing small
|
|
* repeated writes with Nagle enabled.
|
|
*/
|
|
if (so->so_rcv.sb_cc == 0 &&
|
|
tp->last_ack_sent != tp->rcv_nxt &&
|
|
(tp->t_flagsext & TF_LAST_IS_PSH)) {
|
|
goto send;
|
|
}
|
|
}
|
|
}
|
|
if (4 * adv >= (int32_t) so->so_rcv.sb_hiwat) {
|
|
goto send;
|
|
}
|
|
|
|
/*
|
|
* Make sure that the delayed ack timer is set if
|
|
* we delayed sending a window update because of
|
|
* streaming detection.
|
|
*/
|
|
if (tcp_ack_strategy == TCP_ACK_STRATEGY_LEGACY &&
|
|
(tp->t_flags & TF_STRETCHACK) &&
|
|
!(tp->t_flags & TF_DELACK)) {
|
|
tp->t_flags |= TF_DELACK;
|
|
tp->t_timer[TCPT_DELACK] =
|
|
OFFSET_FROM_START(tp, tcp_delack);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Send if we owe the peer an ACK, RST, SYN, or urgent data. ACKNOW
|
|
* is also a catch-all for the retransmit timer timeout case.
|
|
*/
|
|
if (tp->t_flags & TF_ACKNOW) {
|
|
if (tp->t_forced_acks > 0) {
|
|
tp->t_forced_acks--;
|
|
}
|
|
goto send;
|
|
}
|
|
if ((flags & TH_RST) || (flags & TH_SYN)) {
|
|
goto send;
|
|
}
|
|
if (SEQ_GT(tp->snd_up, tp->snd_una)) {
|
|
goto send;
|
|
}
|
|
#if MPTCP
|
|
if (mptcp_acknow) {
|
|
goto send;
|
|
}
|
|
#endif /* MPTCP */
|
|
/*
|
|
* If our state indicates that FIN should be sent
|
|
* and we have not yet done so, then we need to send.
|
|
*/
|
|
if ((flags & TH_FIN) &&
|
|
(!(tp->t_flags & TF_SENTFIN) || tp->snd_nxt == tp->snd_una)) {
|
|
goto send;
|
|
}
|
|
/*
|
|
* In SACK, it is possible for tcp_output to fail to send a segment
|
|
* after the retransmission timer has been turned off. Make sure
|
|
* that the retransmission timer is set.
|
|
*/
|
|
if (SACK_ENABLED(tp) && (tp->t_state >= TCPS_ESTABLISHED) &&
|
|
SEQ_GT(tp->snd_max, tp->snd_una) &&
|
|
tp->t_timer[TCPT_REXMT] == 0 &&
|
|
tp->t_timer[TCPT_PERSIST] == 0) {
|
|
tp->t_timer[TCPT_REXMT] = OFFSET_FROM_START(tp,
|
|
tp->t_rxtcur);
|
|
goto just_return;
|
|
}
|
|
/*
|
|
* TCP window updates are not reliable, rather a polling protocol
|
|
* using ``persist'' packets is used to insure receipt of window
|
|
* updates. The three ``states'' for the output side are:
|
|
* idle not doing retransmits or persists
|
|
* persisting to move a small or zero window
|
|
* (re)transmitting and thereby not persisting
|
|
*
|
|
* tp->t_timer[TCPT_PERSIST]
|
|
* is set when we are in persist state.
|
|
* tp->t_force
|
|
* is set when we are called to send a persist packet.
|
|
* tp->t_timer[TCPT_REXMT]
|
|
* is set when we are retransmitting
|
|
* The output side is idle when both timers are zero.
|
|
*
|
|
* If send window is too small, there is data to transmit, and no
|
|
* retransmit or persist is pending, then go to persist state.
|
|
* If nothing happens soon, send when timer expires:
|
|
* if window is nonzero, transmit what we can,
|
|
* otherwise force out a byte.
|
|
*/
|
|
if (so->so_snd.sb_cc && tp->t_timer[TCPT_REXMT] == 0 &&
|
|
tp->t_timer[TCPT_PERSIST] == 0) {
|
|
TCP_RESET_REXMT_STATE(tp);
|
|
tcp_setpersist(tp);
|
|
}
|
|
just_return:
|
|
/*
|
|
* If there is no reason to send a segment, just return.
|
|
* but if there is some packets left in the packet list, send them now.
|
|
*/
|
|
while (inp->inp_sndinprog_cnt == 0 &&
|
|
tp->t_pktlist_head != NULL) {
|
|
packetlist = tp->t_pktlist_head;
|
|
packchain_listadd = tp->t_lastchain;
|
|
packchain_sent++;
|
|
TCP_PKTLIST_CLEAR(tp);
|
|
|
|
error = tcp_ip_output(so, tp, packetlist,
|
|
packchain_listadd,
|
|
tp_inp_options, (so_options & SO_DONTROUTE),
|
|
(sack_rxmit || (sack_bytes_rxmt != 0)), isipv6);
|
|
}
|
|
/* tcp was closed while we were in ip; resume close */
|
|
if (inp->inp_sndinprog_cnt == 0 &&
|
|
(tp->t_flags & TF_CLOSING)) {
|
|
tp->t_flags &= ~TF_CLOSING;
|
|
(void) tcp_close(tp);
|
|
} else {
|
|
tcp_check_timer_state(tp);
|
|
}
|
|
KERNEL_DEBUG(DBG_FNC_TCP_OUTPUT | DBG_FUNC_END, 0, 0, 0, 0, 0);
|
|
return 0;
|
|
|
|
send:
|
|
/*
|
|
* Set TF_MAXSEGSNT flag if the segment size is greater than
|
|
* the max segment size.
|
|
*/
|
|
if (len > 0) {
|
|
do_not_compress = TRUE;
|
|
|
|
if (len >= tp->t_maxseg) {
|
|
tp->t_flags |= TF_MAXSEGSNT;
|
|
} else {
|
|
tp->t_flags &= ~TF_MAXSEGSNT;
|
|
}
|
|
}
|
|
/*
|
|
* If we are connected and no segment has been ACKed or SACKed yet and we
|
|
* hit a retransmission timeout, then we should disable AccECN option
|
|
* for the rest of the connection.
|
|
*/
|
|
if (TCP_ACC_ECN_ON(tp) && tp->t_state == TCPS_ESTABLISHED &&
|
|
tp->snd_una == tp->iss + 1 && (tp->snd_fack == 0)
|
|
&& tp->t_rxtshift > 0) {
|
|
if ((tp->ecn_flags & TE_RETRY_WITHOUT_ACO) == 0) {
|
|
tp->ecn_flags |= TE_RETRY_WITHOUT_ACO;
|
|
}
|
|
}
|
|
/*
|
|
* Before ESTABLISHED, force sending of initial options
|
|
* unless TCP set not to do any options.
|
|
* NOTE: we assume that the IP/TCP header plus TCP options
|
|
* always fit in a single mbuf, leaving room for a maximum
|
|
* link header, i.e.
|
|
* max_linkhdr + sizeof (struct tcpiphdr) + optlen <= MCLBYTES
|
|
*/
|
|
optlen = 0;
|
|
if (isipv6) {
|
|
hdrlen = sizeof(struct ip6_hdr) + sizeof(struct tcphdr);
|
|
} else {
|
|
hdrlen = sizeof(struct tcpiphdr);
|
|
}
|
|
if (flags & TH_SYN) {
|
|
tp->snd_nxt = tp->iss;
|
|
if ((tp->t_flags & TF_NOOPT) == 0) {
|
|
u_short mss;
|
|
|
|
opt[0] = TCPOPT_MAXSEG;
|
|
opt[1] = TCPOLEN_MAXSEG;
|
|
mss = htons((u_short) tcp_mssopt(tp));
|
|
(void)memcpy(opt + 2, &mss, sizeof(mss));
|
|
optlen = TCPOLEN_MAXSEG;
|
|
|
|
if ((tp->t_flags & TF_REQ_SCALE) &&
|
|
((flags & TH_ACK) == 0 ||
|
|
(tp->t_flags & TF_RCVD_SCALE))) {
|
|
*((u_int32_t *)(void *)(opt + optlen)) = htonl(
|
|
TCPOPT_NOP << 24 |
|
|
TCPOPT_WINDOW << 16 |
|
|
TCPOLEN_WINDOW << 8 |
|
|
tp->request_r_scale);
|
|
optlen += 4;
|
|
}
|
|
#if MPTCP
|
|
if (mptcp_enable && (so->so_flags & SOF_MP_SUBFLOW)) {
|
|
optlen = mptcp_setup_syn_opts(so, opt, optlen);
|
|
}
|
|
#endif /* MPTCP */
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Send a timestamp and echo-reply if this is a SYN and our side
|
|
* wants to use timestamps (TF_REQ_TSTMP is set) or both our side
|
|
* and our peer have sent timestamps in our SYN's.
|
|
*/
|
|
if ((tp->t_flags & (TF_REQ_TSTMP | TF_NOOPT)) == TF_REQ_TSTMP &&
|
|
(flags & TH_RST) == 0 &&
|
|
((flags & TH_ACK) == 0 ||
|
|
(tp->t_flags & TF_RCVD_TSTMP))) {
|
|
u_int32_t *lp = (u_int32_t *)(void *)(opt + optlen);
|
|
|
|
/* Form timestamp option as shown in appendix A of RFC 1323. */
|
|
*lp++ = htonl(TCPOPT_TSTAMP_HDR);
|
|
*lp++ = htonl(tcp_now + tp->t_ts_offset);
|
|
*lp = htonl(tp->ts_recent);
|
|
optlen += TCPOLEN_TSTAMP_APPA;
|
|
}
|
|
|
|
if (SACK_ENABLED(tp) && ((tp->t_flags & TF_NOOPT) == 0)) {
|
|
/*
|
|
* Tack on the SACK permitted option *last*.
|
|
* And do padding of options after tacking this on.
|
|
* This is because of MSS, TS, WinScale and Signatures are
|
|
* all present, we have just 2 bytes left for the SACK
|
|
* permitted option, which is just enough.
|
|
*/
|
|
/*
|
|
* If this is the first SYN of connection (not a SYN
|
|
* ACK), include SACK permitted option. If this is a
|
|
* SYN ACK, include SACK permitted option if peer has
|
|
* already done so. This is only for active connect,
|
|
* since the syncache takes care of the passive connect.
|
|
*/
|
|
if ((flags & TH_SYN) &&
|
|
(!(flags & TH_ACK) || (tp->t_flags & TF_SACK_PERMIT))) {
|
|
u_char *bp;
|
|
bp = (u_char *)opt + optlen;
|
|
|
|
*bp++ = TCPOPT_SACK_PERMITTED;
|
|
*bp++ = TCPOLEN_SACK_PERMITTED;
|
|
optlen += TCPOLEN_SACK_PERMITTED;
|
|
}
|
|
}
|
|
#if MPTCP
|
|
if (so->so_flags & SOF_MP_SUBFLOW) {
|
|
/*
|
|
* Its important to piggyback acks with data as ack only packets
|
|
* may get lost and data packets that don't send Data ACKs
|
|
* still advance the subflow level ACK and therefore make it
|
|
* hard for the remote end to recover in low cwnd situations.
|
|
*/
|
|
if (len != 0) {
|
|
tp->t_mpflags |= (TMPF_SEND_DSN |
|
|
TMPF_MPTCP_ACKNOW);
|
|
} else {
|
|
tp->t_mpflags |= TMPF_MPTCP_ACKNOW;
|
|
}
|
|
optlen = mptcp_setup_opts(tp, off, &opt[0], optlen, flags,
|
|
len, &mptcp_acknow, &do_not_compress);
|
|
tp->t_mpflags &= ~TMPF_SEND_DSN;
|
|
}
|
|
#endif /* MPTCP */
|
|
|
|
if (tfo_enabled(tp) && !(tp->t_flags & TF_NOOPT) &&
|
|
(flags & (TH_SYN | TH_ACK)) == TH_SYN) {
|
|
optlen += tcp_tfo_write_cookie(tp, optlen, len, opt);
|
|
}
|
|
|
|
if (tfo_enabled(tp) &&
|
|
(flags & (TH_SYN | TH_ACK)) == (TH_SYN | TH_ACK) &&
|
|
(tp->t_tfo_flags & TFO_F_OFFER_COOKIE)) {
|
|
optlen += tcp_tfo_write_cookie_rep(tp, optlen, opt);
|
|
}
|
|
|
|
if (SACK_ENABLED(tp) && ((tp->t_flags & TF_NOOPT) == 0)) {
|
|
/*
|
|
* Send SACKs if necessary. This should be the last
|
|
* option processed. Only as many SACKs are sent as
|
|
* are permitted by the maximum options size.
|
|
*
|
|
* In general, SACK blocks consume 8*n+2 bytes.
|
|
* So a full size SACK blocks option is 34 bytes
|
|
* (to generate 4 SACK blocks). At a minimum,
|
|
* we need 10 bytes (to generate 1 SACK block).
|
|
* If TCP Timestamps (12 bytes) and TCP Signatures
|
|
* (18 bytes) are both present, we'll just have
|
|
* 10 bytes for SACK options 40 - (12 + 18).
|
|
*/
|
|
if (TCPS_HAVEESTABLISHED(tp->t_state) &&
|
|
(tp->t_flags & TF_SACK_PERMIT) &&
|
|
(tp->rcv_numsacks > 0 || TCP_SEND_DSACK_OPT(tp)) &&
|
|
MAX_TCPOPTLEN - optlen >= TCPOLEN_SACK + 2) {
|
|
unsigned int sackoptlen = 0;
|
|
int nsack, padlen;
|
|
u_char *bp = (u_char *)opt + optlen;
|
|
u_int32_t *lp;
|
|
|
|
nsack = (MAX_TCPOPTLEN - optlen - 2) / TCPOLEN_SACK;
|
|
nsack = min(nsack, (tp->rcv_numsacks +
|
|
(TCP_SEND_DSACK_OPT(tp) ? 1 : 0)));
|
|
sackoptlen = (2 + nsack * TCPOLEN_SACK);
|
|
VERIFY(sackoptlen < UINT8_MAX);
|
|
|
|
/*
|
|
* First we need to pad options so that the
|
|
* SACK blocks can start at a 4-byte boundary
|
|
* (sack option and length are at a 2 byte offset).
|
|
*/
|
|
padlen = (MAX_TCPOPTLEN - optlen - sackoptlen) % 4;
|
|
optlen += padlen;
|
|
while (padlen-- > 0) {
|
|
*bp++ = TCPOPT_NOP;
|
|
}
|
|
|
|
tcpstat.tcps_sack_send_blocks++;
|
|
*bp++ = TCPOPT_SACK;
|
|
*bp++ = (uint8_t)sackoptlen;
|
|
lp = (u_int32_t *)(void *)bp;
|
|
|
|
/*
|
|
* First block of SACK option should represent
|
|
* DSACK. Prefer to send SACK information if there
|
|
* is space for only one SACK block. This will
|
|
* allow for faster recovery.
|
|
*/
|
|
if (TCP_SEND_DSACK_OPT(tp) && nsack > 0 &&
|
|
(tp->rcv_numsacks == 0 || nsack > 1)) {
|
|
*lp++ = htonl(tp->t_dsack_lseq);
|
|
*lp++ = htonl(tp->t_dsack_rseq);
|
|
tcpstat.tcps_dsack_sent++;
|
|
tp->t_dsack_sent++;
|
|
nsack--;
|
|
}
|
|
VERIFY(nsack == 0 || tp->rcv_numsacks >= nsack);
|
|
for (i = 0; i < nsack; i++) {
|
|
struct sackblk sack = tp->sackblks[i];
|
|
*lp++ = htonl(sack.start);
|
|
*lp++ = htonl(sack.end);
|
|
}
|
|
optlen += sackoptlen;
|
|
|
|
/* Make sure we didn't write too much */
|
|
VERIFY((u_char *)lp - opt <= MAX_TCPOPTLEN);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* AccECN option - after SACK
|
|
* Don't send on <SYN>,
|
|
* send only on <SYN,ACK> before ACCECN is negotiated or
|
|
* when doing an AccECN session. Don't send AccECN option
|
|
* if retransmitting a SYN-ACK or a data segment
|
|
*/
|
|
if ((TCP_ACC_ECN_ON(tp) ||
|
|
(TCP_ACC_ECN_ENABLED(tp) && (flags & (TH_SYN | TH_ACK)) == (TH_SYN | TH_ACK)))
|
|
&& ((tp->ecn_flags & TE_RETRY_WITHOUT_ACO) == 0)) {
|
|
uint32_t *lp = (uint32_t *)(void *)(opt + optlen);
|
|
/* lp will become outdated after options are added */
|
|
tcp_add_accecn_option(tp, flags, lp, (uint8_t *)&optlen);
|
|
}
|
|
/* Pad TCP options to a 4 byte boundary */
|
|
if (optlen < MAX_TCPOPTLEN && (optlen % sizeof(u_int32_t))) {
|
|
int pad = sizeof(u_int32_t) - (optlen % sizeof(u_int32_t));
|
|
u_char *bp = (u_char *)opt + optlen;
|
|
|
|
optlen += pad;
|
|
while (pad) {
|
|
*bp++ = TCPOPT_EOL;
|
|
pad--;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* For Accurate ECN, send ACE flag based on r.cep, if
|
|
* We have completed handshake and are in ESTABLISHED state, and
|
|
* This is not the final ACK of 3WHS.
|
|
*/
|
|
if (TCP_ACC_ECN_ON(tp) && TCPS_HAVEESTABLISHED(tp->t_state) &&
|
|
(tp->ecn_flags & TE_ACE_FINAL_ACK_3WHS) == 0) {
|
|
uint8_t ace = tp->t_rcv_ce_packets & TCP_ACE_MASK;
|
|
if (ace & 0x01) {
|
|
flags |= TH_ECE;
|
|
} else {
|
|
flags &= ~TH_ECE;
|
|
}
|
|
if (ace & 0x02) {
|
|
flags |= TH_CWR;
|
|
} else {
|
|
flags &= ~TH_CWR;
|
|
}
|
|
if (ace & 0x04) {
|
|
flags |= TH_AE;
|
|
} else {
|
|
flags &= ~TH_AE;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* RFC 3168 states that:
|
|
* - If you ever sent an ECN-setup SYN/SYN-ACK you must be prepared
|
|
* to handle the TCP ECE flag, even if you also later send a
|
|
* non-ECN-setup SYN/SYN-ACK.
|
|
* - If you ever send a non-ECN-setup SYN/SYN-ACK, you must not set
|
|
* the ip ECT flag.
|
|
*
|
|
* It is not clear how the ECE flag would ever be set if you never
|
|
* set the IP ECT flag on outbound packets. All the same, we use
|
|
* the TE_SETUPSENT to indicate that we have committed to handling
|
|
* the TCP ECE flag correctly. We use the TE_SENDIPECT to indicate
|
|
* whether or not we should set the IP ECT flag on outbound packet
|
|
*
|
|
* For a SYN-ACK, send an ECN setup SYN-ACK
|
|
*
|
|
* Below we send ECN for three different handhshake states:
|
|
* 1. Server received SYN and is sending a SYN-ACK (state->TCPS_SYN_RECEIVED)
|
|
* - both classic and Accurate ECN have special encoding
|
|
* 2. Client is sending SYN packet (state->SYN_SENT)
|
|
* - both classic and Accurate ECN have special encoding
|
|
* 3. Client is sending final ACK of 3WHS (state->ESTABLISHED)
|
|
* - Only Accurate ECN has special encoding
|
|
*/
|
|
if ((flags & (TH_SYN | TH_ACK)) == (TH_SYN | TH_ACK) &&
|
|
(tp->ecn_flags & TE_ENABLE_ECN)) {
|
|
/* Server received either legacy or Accurate ECN setup SYN */
|
|
if (tp->ecn_flags & (TE_SETUPRECEIVED | TE_ACE_SETUPRECEIVED)) {
|
|
if (tcp_send_ecn_flags_on_syn(tp)) {
|
|
if (TCP_ACC_ECN_ENABLED(tp) && (tp->ecn_flags & TE_ACE_SETUPRECEIVED)) {
|
|
/*
|
|
* Accurate ECN mode is on. Initialize packet and byte counters
|
|
* for the server sending SYN-ACK. Although s_cep will be initialized
|
|
* during input processing of ACK of SYN-ACK, initialize here as well
|
|
* in case ACK gets lost.
|
|
*
|
|
* Non-zero initial values are used to
|
|
* support a stateless handshake (see
|
|
* Section 5.1 of AccECN draft) and to be
|
|
* distinct from cases where the fields
|
|
* are incorrectly zeroed.
|
|
*/
|
|
tp->t_rcv_ce_packets = 5;
|
|
tp->t_snd_ce_packets = 5;
|
|
|
|
/* Initialize CE byte counter to 0 */
|
|
tp->t_rcv_ce_bytes = tp->t_snd_ce_bytes = 0;
|
|
|
|
if (tp->ecn_flags & TE_ACE_SETUP_NON_ECT) {
|
|
tp->t_prev_ace_flags = TH_CWR;
|
|
flags |= tp->t_prev_ace_flags;
|
|
/* Remove the setup flag as it is also used for final ACK */
|
|
tp->ecn_flags &= ~TE_ACE_SETUP_NON_ECT;
|
|
tcpstat.tcps_ecn_ace_syn_not_ect++;
|
|
} else if (tp->ecn_flags & TE_ACE_SETUP_ECT1) {
|
|
tp->t_prev_ace_flags = (TH_CWR | TH_ECE);
|
|
flags |= tp->t_prev_ace_flags;
|
|
tp->ecn_flags &= ~TE_ACE_SETUP_ECT1;
|
|
tcpstat.tcps_ecn_ace_syn_ect1++;
|
|
} else if (tp->ecn_flags & TE_ACE_SETUP_ECT0) {
|
|
tp->t_prev_ace_flags = TH_AE;
|
|
flags |= tp->t_prev_ace_flags;
|
|
tp->ecn_flags &= ~TE_ACE_SETUP_ECT0;
|
|
tcpstat.tcps_ecn_ace_syn_ect0++;
|
|
} else if (tp->ecn_flags & TE_ACE_SETUP_CE) {
|
|
tp->t_prev_ace_flags = (TH_AE | TH_CWR);
|
|
flags |= tp->t_prev_ace_flags;
|
|
tp->ecn_flags &= ~TE_ACE_SETUP_CE;
|
|
/*
|
|
* Receive counter is updated on
|
|
* all acceptable packets except
|
|
* CE on SYN packets (SYN=1, ACK=0)
|
|
*/
|
|
tcpstat.tcps_ecn_ace_syn_ce++;
|
|
} else {
|
|
if (tp->t_prev_ace_flags != 0) {
|
|
/* Set the flags for retransmitted SYN-ACK same as the previous one */
|
|
flags |= tp->t_prev_ace_flags;
|
|
} else {
|
|
/* We shouldn't come here */
|
|
panic("ECN flags (0x%x) not set correctly", tp->ecn_flags);
|
|
}
|
|
}
|
|
/*
|
|
* We are not yet committing to send IP ECT packets when
|
|
* Accurate ECN mode is on
|
|
*/
|
|
tp->ecn_flags |= (TE_ACE_SETUPSENT);
|
|
} else if (tp->ecn_flags & TE_SETUPRECEIVED) {
|
|
/*
|
|
* Setting TH_ECE makes this an ECN-setup
|
|
* SYN-ACK
|
|
*/
|
|
flags |= TH_ECE;
|
|
/*
|
|
* Record that we sent the ECN-setup and
|
|
* default to setting IP ECT.
|
|
*/
|
|
tp->ecn_flags |= (TE_SETUPSENT | TE_SENDIPECT);
|
|
}
|
|
tcpstat.tcps_ecn_server_setup++;
|
|
tcpstat.tcps_ecn_server_success++;
|
|
} else {
|
|
/*
|
|
* For classic ECN, we sent an ECN-setup SYN-ACK but it was
|
|
* dropped. Fallback to non-ECN-setup
|
|
* SYN-ACK and clear flag to indicate that
|
|
* we should not send data with IP ECT set
|
|
*
|
|
* Pretend we didn't receive an
|
|
* ECN-setup SYN.
|
|
*
|
|
* We already incremented the counter
|
|
* assuming that the ECN setup will
|
|
* succeed. Decrementing here
|
|
* tcps_ecn_server_success to correct it.
|
|
*
|
|
* For Accurate ECN, we don't yet remove TE_ACE_SETUPRECEIVED
|
|
* as the client might have received Accurate ECN SYN-ACK.
|
|
* We decide Accurate ECN's state on processing last ACK from the client.
|
|
*/
|
|
if (tp->ecn_flags & (TE_SETUPSENT | TE_ACE_SETUPSENT)) {
|
|
tcpstat.tcps_ecn_lost_synack++;
|
|
tcpstat.tcps_ecn_server_success--;
|
|
tp->ecn_flags |= TE_LOST_SYNACK;
|
|
}
|
|
|
|
tp->ecn_flags &=
|
|
~(TE_SETUPRECEIVED | TE_SENDIPECT |
|
|
TE_SENDCWR);
|
|
}
|
|
}
|
|
} else if ((flags & (TH_SYN | TH_ACK)) == TH_SYN &&
|
|
(tp->ecn_flags & TE_ENABLE_ECN)) {
|
|
if (tcp_send_ecn_flags_on_syn(tp)) {
|
|
if (TCP_ACC_ECN_ENABLED(tp)) {
|
|
/* We are negotiating AccECN in SYN */
|
|
flags |= TH_ACE;
|
|
/*
|
|
* For AccECN, we only set the ECN-setup sent
|
|
* flag as we are not committing to set ECT yet.
|
|
*/
|
|
tp->ecn_flags |= (TE_ACE_SETUPSENT);
|
|
} else {
|
|
/*
|
|
* Setting TH_ECE and TH_CWR makes this an
|
|
* ECN-setup SYN
|
|
*/
|
|
flags |= (TH_ECE | TH_CWR);
|
|
/*
|
|
* Record that we sent the ECN-setup and default to
|
|
* setting IP ECT.
|
|
*/
|
|
tp->ecn_flags |= (TE_SETUPSENT | TE_SENDIPECT);
|
|
}
|
|
tcpstat.tcps_ecn_client_setup++;
|
|
tp->ecn_flags |= TE_CLIENT_SETUP;
|
|
} else {
|
|
/*
|
|
* We sent an ECN-setup SYN but it was dropped.
|
|
* Fall back to non-ECN and clear flag indicating
|
|
* we should send data with IP ECT set.
|
|
*/
|
|
if (tp->ecn_flags & (TE_SETUPSENT | TE_ACE_SETUPSENT)) {
|
|
tcpstat.tcps_ecn_lost_syn++;
|
|
tp->ecn_flags |= TE_LOST_SYN;
|
|
}
|
|
tp->ecn_flags &= ~TE_SENDIPECT;
|
|
}
|
|
} else if (TCP_ACC_ECN_ON(tp) && (tp->ecn_flags & TE_ACE_FINAL_ACK_3WHS) &&
|
|
len == 0 && (flags & (TH_FLAGS_ALL)) == TH_ACK) {
|
|
/*
|
|
* Client has processed SYN-ACK and moved to ESTABLISHED.
|
|
* This is the final ACK of 3WHS. If ACC_ECN has been negotiated,
|
|
* then send the handshake encoding as per Table 3 of Accurate ECN draft.
|
|
* We are clearing the ACE flags just in case if they were set before.
|
|
* TODO: if client has to carry data in the 3WHS ACK, then we need to send a pure ACK first
|
|
*/
|
|
flags &= ~(TH_AE | TH_CWR | TH_ECE);
|
|
if (tp->ecn_flags & TE_ACE_SETUP_NON_ECT) {
|
|
flags |= TH_CWR;
|
|
tp->ecn_flags &= ~TE_ACE_SETUP_NON_ECT;
|
|
} else if (tp->ecn_flags & TE_ACE_SETUP_ECT1) {
|
|
flags |= (TH_CWR | TH_ECE);
|
|
tp->ecn_flags &= ~TE_ACE_SETUP_ECT1;
|
|
} else if (tp->ecn_flags & TE_ACE_SETUP_ECT0) {
|
|
flags |= TH_AE;
|
|
tp->ecn_flags &= ~TE_ACE_SETUP_ECT0;
|
|
} else if (tp->ecn_flags & TE_ACE_SETUP_CE) {
|
|
flags |= (TH_AE | TH_CWR);
|
|
tp->ecn_flags &= ~TE_ACE_SETUP_CE;
|
|
}
|
|
tp->ecn_flags &= ~(TE_ACE_FINAL_ACK_3WHS);
|
|
}
|
|
|
|
/*
|
|
* Check if we should set the TCP CWR flag.
|
|
* CWR flag is sent when we reduced the congestion window because
|
|
* we received a TCP ECE or we performed a fast retransmit. We
|
|
* never set the CWR flag on retransmitted packets. We only set
|
|
* the CWR flag on data packets. Pure acks don't have this set.
|
|
*/
|
|
if ((tp->ecn_flags & TE_SENDCWR) != 0 && len != 0 &&
|
|
!SEQ_LT(tp->snd_nxt, tp->snd_max) && !sack_rxmit) {
|
|
flags |= TH_CWR;
|
|
tp->ecn_flags &= ~TE_SENDCWR;
|
|
}
|
|
|
|
/*
|
|
* Check if we should set the TCP ECE flag.
|
|
*/
|
|
if ((tp->ecn_flags & TE_SENDECE) != 0 && len == 0) {
|
|
flags |= TH_ECE;
|
|
tcpstat.tcps_ecn_sent_ece++;
|
|
}
|
|
|
|
hdrlen += optlen;
|
|
|
|
/* Reset DSACK sequence numbers */
|
|
tp->t_dsack_lseq = 0;
|
|
tp->t_dsack_rseq = 0;
|
|
|
|
if (isipv6) {
|
|
ipoptlen = ip6_optlen(inp);
|
|
} else {
|
|
if (tp_inp_options) {
|
|
ipoptlen = tp_inp_options->m_len -
|
|
offsetof(struct ipoption, ipopt_list);
|
|
} else {
|
|
ipoptlen = 0;
|
|
}
|
|
}
|
|
#if IPSEC
|
|
ipoptlen += ipsec_optlen;
|
|
#endif
|
|
|
|
/*
|
|
* Adjust data length if insertion of options will
|
|
* bump the packet length beyond the t_maxopd length.
|
|
* Clear the FIN bit because we cut off the tail of
|
|
* the segment.
|
|
*
|
|
* When doing TSO limit a burst to TCP_MAXWIN minus the
|
|
* IP, TCP and Options length to keep ip->ip_len from
|
|
* overflowing. Prevent the last segment from being
|
|
* fractional thus making them all equal sized and set
|
|
* the flag to continue sending. TSO is disabled when
|
|
* IP options or IPSEC are present.
|
|
*/
|
|
if (len + optlen + ipoptlen > tp->t_maxopd) {
|
|
/*
|
|
* If there is still more to send,
|
|
* don't close the connection.
|
|
*/
|
|
flags &= ~TH_FIN;
|
|
if (tso) {
|
|
int32_t tso_maxlen;
|
|
|
|
tso_maxlen = tp->tso_max_segment_size ?
|
|
tp->tso_max_segment_size : TCP_MAXWIN;
|
|
|
|
/* hdrlen includes optlen */
|
|
if (len > tso_maxlen - hdrlen) {
|
|
len = tso_maxlen - hdrlen;
|
|
sendalot = 1;
|
|
} else if (tp->t_flags & TF_NEEDFIN) {
|
|
sendalot = 1;
|
|
}
|
|
|
|
if (len % (tp->t_maxopd - optlen) != 0) {
|
|
len = len - (len % (tp->t_maxopd - optlen));
|
|
sendalot = 1;
|
|
}
|
|
} else {
|
|
len = tp->t_maxopd - optlen - ipoptlen;
|
|
sendalot = 1;
|
|
}
|
|
}
|
|
|
|
if (max_linkhdr + hdrlen > MCLBYTES) {
|
|
panic("tcphdr too big");
|
|
}
|
|
|
|
/* Check if there is enough data in the send socket
|
|
* buffer to start measuring bandwidth
|
|
*/
|
|
if ((tp->t_flagsext & TF_MEASURESNDBW) != 0 &&
|
|
(tp->t_bwmeas != NULL) &&
|
|
(tp->t_flagsext & TF_BWMEAS_INPROGRESS) == 0) {
|
|
tp->t_bwmeas->bw_size = min(min(
|
|
(so->so_snd.sb_cc - (tp->snd_max - tp->snd_una)),
|
|
tp->snd_cwnd), tp->snd_wnd);
|
|
if (tp->t_bwmeas->bw_minsize > 0 &&
|
|
tp->t_bwmeas->bw_size < tp->t_bwmeas->bw_minsize) {
|
|
tp->t_bwmeas->bw_size = 0;
|
|
}
|
|
if (tp->t_bwmeas->bw_maxsize > 0) {
|
|
tp->t_bwmeas->bw_size = min(tp->t_bwmeas->bw_size,
|
|
tp->t_bwmeas->bw_maxsize);
|
|
}
|
|
if (tp->t_bwmeas->bw_size > 0) {
|
|
tp->t_flagsext |= TF_BWMEAS_INPROGRESS;
|
|
tp->t_bwmeas->bw_start = tp->snd_max;
|
|
tp->t_bwmeas->bw_ts = tcp_now;
|
|
}
|
|
}
|
|
|
|
VERIFY(inp->inp_flowhash != 0);
|
|
/*
|
|
* Grab a header mbuf, attaching a copy of data to
|
|
* be transmitted, and initialize the header from
|
|
* the template for sends on this connection.
|
|
*/
|
|
if (len) {
|
|
/* Remember what the last head-of-line packet-size was */
|
|
if (tp->t_pmtud_lastseg_size == 0 && tp->snd_nxt == tp->snd_una) {
|
|
ASSERT(len + optlen + ipoptlen <= IP_MAXPACKET);
|
|
tp->t_pmtud_lastseg_size = (uint16_t)(len + optlen + ipoptlen);
|
|
}
|
|
if ((tp->t_flagsext & TF_FORCE) && len == 1) {
|
|
tcpstat.tcps_sndprobe++;
|
|
} else if (SEQ_LT(tp->snd_nxt, tp->snd_max) || sack_rxmit) {
|
|
tcpstat.tcps_sndrexmitpack++;
|
|
tcpstat.tcps_sndrexmitbyte += len;
|
|
if (nstat_collect) {
|
|
nstat_route_tx(inp->inp_route.ro_rt, 1,
|
|
len, NSTAT_TX_FLAG_RETRANSMIT);
|
|
INP_ADD_STAT(inp, cell, wifi, wired,
|
|
txpackets, 1);
|
|
INP_ADD_STAT(inp, cell, wifi, wired,
|
|
txbytes, len);
|
|
tp->t_stat.txretransmitbytes += len;
|
|
tp->t_stat.rxmitpkts++;
|
|
}
|
|
if (tp->ecn_flags & TE_SENDIPECT) {
|
|
tp->t_ecn_capable_packets_lost++;
|
|
}
|
|
} else {
|
|
tcpstat.tcps_sndpack++;
|
|
tcpstat.tcps_sndbyte += len;
|
|
|
|
if (nstat_collect) {
|
|
INP_ADD_STAT(inp, cell, wifi, wired,
|
|
txpackets, 1);
|
|
INP_ADD_STAT(inp, cell, wifi, wired,
|
|
txbytes, len);
|
|
}
|
|
if (tp->ecn_flags & TE_SENDIPECT) {
|
|
tp->t_ecn_capable_packets_sent++;
|
|
}
|
|
inp_decr_sndbytes_unsent(so, len);
|
|
}
|
|
inp_set_activity_bitmap(inp);
|
|
#if MPTCP
|
|
if (tp->t_mpflags & TMPF_MPTCP_TRUE) {
|
|
tcpstat.tcps_mp_sndpacks++;
|
|
tcpstat.tcps_mp_sndbytes += len;
|
|
}
|
|
#endif /* MPTCP */
|
|
/*
|
|
* try to use the new interface that allocates all
|
|
* the necessary mbuf hdrs under 1 mbuf lock and
|
|
* avoids rescanning the socket mbuf list if
|
|
* certain conditions are met. This routine can't
|
|
* be used in the following cases...
|
|
* 1) the protocol headers exceed the capacity of
|
|
* of a single mbuf header's data area (no cluster attached)
|
|
* 2) the length of the data being transmitted plus
|
|
* the protocol headers fits into a single mbuf header's
|
|
* data area (no cluster attached)
|
|
*/
|
|
m = NULL;
|
|
|
|
/* minimum length we are going to allocate */
|
|
allocated_len = MHLEN;
|
|
if (MHLEN < hdrlen + max_linkhdr) {
|
|
MGETHDR(m, M_DONTWAIT, MT_HEADER);
|
|
if (m == NULL) {
|
|
error = ENOBUFS;
|
|
goto out;
|
|
}
|
|
MCLGET(m, M_DONTWAIT);
|
|
if ((m->m_flags & M_EXT) == 0) {
|
|
m_freem(m);
|
|
error = ENOBUFS;
|
|
goto out;
|
|
}
|
|
m->m_data += max_linkhdr;
|
|
m->m_len = hdrlen;
|
|
allocated_len = MCLBYTES;
|
|
}
|
|
if (len <= allocated_len - hdrlen - max_linkhdr) {
|
|
if (m == NULL) {
|
|
VERIFY(allocated_len <= MHLEN);
|
|
MGETHDR(m, M_DONTWAIT, MT_HEADER);
|
|
if (m == NULL) {
|
|
error = ENOBUFS;
|
|
goto out;
|
|
}
|
|
m->m_data += max_linkhdr;
|
|
m->m_len = hdrlen;
|
|
}
|
|
/* makes sure we still have data left to be sent at this point */
|
|
if (so->so_snd.sb_mb == NULL || off < 0) {
|
|
if (m != NULL) {
|
|
m_freem(m);
|
|
}
|
|
error = 0; /* should we return an error? */
|
|
goto out;
|
|
}
|
|
m_copydata(so->so_snd.sb_mb, off, (int) len,
|
|
mtod(m, caddr_t) + hdrlen);
|
|
m->m_len += len;
|
|
} else {
|
|
uint32_t copymode;
|
|
/*
|
|
* Retain packet header metadata at the socket
|
|
* buffer if this is is an MPTCP subflow,
|
|
* otherwise move it.
|
|
*/
|
|
copymode = M_COPYM_MOVE_HDR;
|
|
#if MPTCP
|
|
if (so->so_flags & SOF_MP_SUBFLOW) {
|
|
copymode = M_COPYM_NOOP_HDR;
|
|
}
|
|
#endif /* MPTCP */
|
|
if (m != NULL) {
|
|
if (so->so_snd.sb_flags & SB_SENDHEAD) {
|
|
VERIFY(so->so_snd.sb_flags & SB_SENDHEAD);
|
|
VERIFY(so->so_snd.sb_sendoff <= so->so_snd.sb_cc);
|
|
|
|
m->m_next = m_copym_mode(so->so_snd.sb_mb,
|
|
off, (int)len, M_DONTWAIT,
|
|
&so->so_snd.sb_sendhead,
|
|
&so->so_snd.sb_sendoff, copymode);
|
|
|
|
VERIFY(so->so_snd.sb_sendoff <= so->so_snd.sb_cc);
|
|
} else {
|
|
m->m_next = m_copym_mode(so->so_snd.sb_mb,
|
|
off, (int)len, M_DONTWAIT,
|
|
NULL, NULL, copymode);
|
|
}
|
|
if (m->m_next == NULL) {
|
|
(void) m_free(m);
|
|
error = ENOBUFS;
|
|
goto out;
|
|
}
|
|
} else {
|
|
/*
|
|
* make sure we still have data left
|
|
* to be sent at this point
|
|
*/
|
|
if (so->so_snd.sb_mb == NULL) {
|
|
error = 0; /* should we return an error? */
|
|
goto out;
|
|
}
|
|
|
|
/*
|
|
* m_copym_with_hdrs will always return the
|
|
* last mbuf pointer and the offset into it that
|
|
* it acted on to fullfill the current request,
|
|
* whether a valid 'hint' was passed in or not.
|
|
*/
|
|
if (so->so_snd.sb_flags & SB_SENDHEAD) {
|
|
VERIFY(so->so_snd.sb_flags & SB_SENDHEAD);
|
|
VERIFY(so->so_snd.sb_sendoff <= so->so_snd.sb_cc);
|
|
|
|
m = m_copym_with_hdrs(so->so_snd.sb_mb,
|
|
off, len, M_DONTWAIT, &so->so_snd.sb_sendhead,
|
|
&so->so_snd.sb_sendoff, copymode);
|
|
|
|
VERIFY(so->so_snd.sb_sendoff <= so->so_snd.sb_cc);
|
|
} else {
|
|
m = m_copym_with_hdrs(so->so_snd.sb_mb,
|
|
off, len, M_DONTWAIT, NULL,
|
|
NULL, copymode);
|
|
}
|
|
if (m == NULL) {
|
|
error = ENOBUFS;
|
|
goto out;
|
|
}
|
|
m->m_data += max_linkhdr;
|
|
m->m_len = hdrlen;
|
|
}
|
|
}
|
|
/*
|
|
* If we're sending everything we've got, set PUSH.
|
|
* (This will keep happy those implementations which only
|
|
* give data to the user when a buffer fills or
|
|
* a PUSH comes in.)
|
|
*
|
|
* On SYN-segments we should not add the PUSH-flag.
|
|
*/
|
|
if (off + len == so->so_snd.sb_cc && !(flags & TH_SYN)) {
|
|
flags |= TH_PUSH;
|
|
}
|
|
} else {
|
|
if (tp->t_flags & TF_ACKNOW) {
|
|
tcpstat.tcps_sndacks++;
|
|
} else if (flags & (TH_SYN | TH_FIN | TH_RST)) {
|
|
tcpstat.tcps_sndctrl++;
|
|
} else if (SEQ_GT(tp->snd_up, tp->snd_una)) {
|
|
tcpstat.tcps_sndurg++;
|
|
} else {
|
|
tcpstat.tcps_sndwinup++;
|
|
}
|
|
|
|
MGETHDR(m, M_DONTWAIT, MT_HEADER); /* MAC-OK */
|
|
if (m == NULL) {
|
|
error = ENOBUFS;
|
|
goto out;
|
|
}
|
|
if (MHLEN < (hdrlen + max_linkhdr)) {
|
|
MCLGET(m, M_DONTWAIT);
|
|
if ((m->m_flags & M_EXT) == 0) {
|
|
m_freem(m);
|
|
error = ENOBUFS;
|
|
goto out;
|
|
}
|
|
}
|
|
m->m_data += max_linkhdr;
|
|
m->m_len = hdrlen;
|
|
}
|
|
m->m_pkthdr.rcvif = 0;
|
|
m_add_crumb(m, PKT_CRUMB_TCP_OUTPUT);
|
|
|
|
/* Any flag other than pure-ACK: Do not compress! */
|
|
if (flags & ~(TH_ACK)) {
|
|
do_not_compress = TRUE;
|
|
}
|
|
|
|
if (tp->rcv_scale == 0) {
|
|
do_not_compress = TRUE;
|
|
}
|
|
|
|
if (do_not_compress) {
|
|
m->m_pkthdr.comp_gencnt = 0;
|
|
} else {
|
|
if (TSTMP_LT(tp->t_comp_lastinc + tcp_ack_compression_rate, tcp_now)) {
|
|
tp->t_comp_gencnt++;
|
|
/* 0 means no compression, thus jump this */
|
|
if (tp->t_comp_gencnt <= TCP_ACK_COMPRESSION_DUMMY) {
|
|
tp->t_comp_gencnt = TCP_ACK_COMPRESSION_DUMMY + 1;
|
|
}
|
|
tp->t_comp_lastinc = tcp_now;
|
|
}
|
|
m->m_pkthdr.comp_gencnt = tp->t_comp_gencnt;
|
|
}
|
|
|
|
if (isipv6) {
|
|
ip6 = mtod(m, struct ip6_hdr *);
|
|
th = (struct tcphdr *)(void *)(ip6 + 1);
|
|
tcp_fillheaders(m, tp, ip6, th);
|
|
if ((tp->ecn_flags & TE_SENDIPECT) != 0 && len &&
|
|
!SEQ_LT(tp->snd_nxt, tp->snd_max) && !sack_rxmit) {
|
|
ip6->ip6_flow |= htonl(IPTOS_ECN_ECT0 << 20);
|
|
}
|
|
svc_flags |= PKT_SCF_IPV6;
|
|
#if PF_ECN
|
|
m_pftag(m)->pftag_hdr = (void *)ip6;
|
|
m_pftag(m)->pftag_flags |= PF_TAG_HDR_INET6;
|
|
#endif /* PF_ECN */
|
|
} else {
|
|
ip = mtod(m, struct ip *);
|
|
th = (struct tcphdr *)(void *)(ip + 1);
|
|
/* this picks up the pseudo header (w/o the length) */
|
|
tcp_fillheaders(m, tp, ip, th);
|
|
if ((tp->ecn_flags & TE_SENDIPECT) != 0 && len &&
|
|
!SEQ_LT(tp->snd_nxt, tp->snd_max) &&
|
|
!sack_rxmit && !(flags & TH_SYN)) {
|
|
ip->ip_tos |= IPTOS_ECN_ECT0;
|
|
}
|
|
#if PF_ECN
|
|
m_pftag(m)->pftag_hdr = (void *)ip;
|
|
m_pftag(m)->pftag_flags |= PF_TAG_HDR_INET;
|
|
#endif /* PF_ECN */
|
|
}
|
|
|
|
/*
|
|
* Fill in fields, remembering maximum advertised
|
|
* window for use in delaying messages about window sizes.
|
|
* If resending a FIN, be sure not to use a new sequence number.
|
|
*/
|
|
if ((flags & TH_FIN) && (tp->t_flags & TF_SENTFIN) &&
|
|
tp->snd_nxt == tp->snd_max) {
|
|
tp->snd_nxt--;
|
|
}
|
|
/*
|
|
* If we are doing retransmissions, then snd_nxt will
|
|
* not reflect the first unsent octet. For ACK only
|
|
* packets, we do not want the sequence number of the
|
|
* retransmitted packet, we want the sequence number
|
|
* of the next unsent octet. So, if there is no data
|
|
* (and no SYN or FIN), use snd_max instead of snd_nxt
|
|
* when filling in ti_seq. But if we are in persist
|
|
* state, snd_max might reflect one byte beyond the
|
|
* right edge of the window, so use snd_nxt in that
|
|
* case, since we know we aren't doing a retransmission.
|
|
* (retransmit and persist are mutually exclusive...)
|
|
*
|
|
* Note the state of this retransmit segment to detect spurious
|
|
* retransmissions.
|
|
*/
|
|
if (sack_rxmit == 0) {
|
|
if (len || (flags & (TH_SYN | TH_FIN)) ||
|
|
tp->t_timer[TCPT_PERSIST]) {
|
|
th->th_seq = htonl(tp->snd_nxt);
|
|
if (len > 0) {
|
|
m->m_pkthdr.tx_start_seq = tp->snd_nxt;
|
|
m->m_pkthdr.pkt_flags |= PKTF_START_SEQ;
|
|
}
|
|
if (SEQ_LT(tp->snd_nxt, tp->snd_max)) {
|
|
if (SACK_ENABLED(tp) && len > 1 &&
|
|
!(tp->t_flagsext & TF_SENT_TLPROBE)) {
|
|
tcp_rxtseg_insert(tp, tp->snd_nxt,
|
|
(tp->snd_nxt + len - 1));
|
|
}
|
|
if (len > 0) {
|
|
m->m_pkthdr.pkt_flags |=
|
|
PKTF_TCP_REXMT;
|
|
}
|
|
}
|
|
} else {
|
|
th->th_seq = htonl(tp->snd_max);
|
|
}
|
|
} else {
|
|
th->th_seq = htonl(p->rxmit);
|
|
if (len > 0) {
|
|
m->m_pkthdr.pkt_flags |=
|
|
(PKTF_TCP_REXMT | PKTF_START_SEQ);
|
|
m->m_pkthdr.tx_start_seq = p->rxmit;
|
|
}
|
|
tcp_rxtseg_insert(tp, p->rxmit, (p->rxmit + len - 1));
|
|
p->rxmit += len;
|
|
tp->sackhint.sack_bytes_rexmit += len;
|
|
}
|
|
th->th_ack = htonl(tp->rcv_nxt);
|
|
tp->last_ack_sent = tp->rcv_nxt;
|
|
if (optlen) {
|
|
bcopy(opt, th + 1, optlen);
|
|
th->th_off = (sizeof(struct tcphdr) + optlen) >> 2;
|
|
}
|
|
/* Separate AE from flags */
|
|
th->th_flags = (flags & (TH_FLAGS_ALL));
|
|
th->th_x2 = (flags & (TH_AE)) >> 8;
|
|
th->th_win = htons((u_short) (recwin >> tp->rcv_scale));
|
|
tp->t_last_recwin = recwin;
|
|
if (!(so->so_flags & SOF_MP_SUBFLOW)) {
|
|
if (recwin > 0 && SEQ_LT(tp->rcv_adv, tp->rcv_nxt + recwin)) {
|
|
tp->rcv_adv = tp->rcv_nxt + recwin;
|
|
}
|
|
} else {
|
|
struct mptcb *mp_tp = tptomptp(tp);
|
|
if (recwin > 0) {
|
|
tp->rcv_adv = tp->rcv_nxt + recwin;
|
|
}
|
|
|
|
if (recwin > 0 && MPTCP_SEQ_LT(mp_tp->mpt_rcvadv, mp_tp->mpt_rcvnxt + recwin)) {
|
|
mp_tp->mpt_rcvadv = mp_tp->mpt_rcvnxt + recwin;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Adjust the RXWIN0SENT flag - indicate that we have advertised
|
|
* a 0 window. This may cause the remote transmitter to stall. This
|
|
* flag tells soreceive() to disable delayed acknowledgements when
|
|
* draining the buffer. This can occur if the receiver is attempting
|
|
* to read more data then can be buffered prior to transmitting on
|
|
* the connection.
|
|
*/
|
|
if (th->th_win == 0) {
|
|
tp->t_flags |= TF_RXWIN0SENT;
|
|
} else {
|
|
tp->t_flags &= ~TF_RXWIN0SENT;
|
|
}
|
|
|
|
if (SEQ_GT(tp->snd_up, tp->snd_nxt)) {
|
|
th->th_urp = htons((u_short)(tp->snd_up - tp->snd_nxt));
|
|
th->th_flags |= TH_URG;
|
|
} else {
|
|
/*
|
|
* If no urgent pointer to send, then we pull
|
|
* the urgent pointer to the left edge of the send window
|
|
* so that it doesn't drift into the send window on sequence
|
|
* number wraparound.
|
|
*/
|
|
tp->snd_up = tp->snd_una; /* drag it along */
|
|
}
|
|
|
|
/*
|
|
* Put TCP length in extended header, and then
|
|
* checksum extended header and data.
|
|
*/
|
|
m->m_pkthdr.len = hdrlen + len; /* in6_cksum() need this */
|
|
|
|
/*
|
|
* If this is potentially the last packet on the stream, then mark
|
|
* it in order to enable some optimizations in the underlying
|
|
* layers
|
|
*/
|
|
if (tp->t_state != TCPS_ESTABLISHED &&
|
|
(tp->t_state == TCPS_CLOSING || tp->t_state == TCPS_TIME_WAIT
|
|
|| tp->t_state == TCPS_LAST_ACK || (th->th_flags & TH_RST))) {
|
|
m->m_pkthdr.pkt_flags |= PKTF_LAST_PKT;
|
|
}
|
|
|
|
if (isipv6) {
|
|
/*
|
|
* ip6_plen is not need to be filled now, and will be filled
|
|
* in ip6_output.
|
|
*/
|
|
m->m_pkthdr.csum_flags = CSUM_TCPIPV6;
|
|
m->m_pkthdr.csum_data = offsetof(struct tcphdr, th_sum);
|
|
if (len + optlen) {
|
|
th->th_sum = in_addword(th->th_sum,
|
|
htons((u_short)(optlen + len)));
|
|
}
|
|
} else {
|
|
m->m_pkthdr.csum_flags = CSUM_TCP;
|
|
m->m_pkthdr.csum_data = offsetof(struct tcphdr, th_sum);
|
|
if (len + optlen) {
|
|
th->th_sum = in_addword(th->th_sum,
|
|
htons((u_short)(optlen + len)));
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Enable TSO and specify the size of the segments.
|
|
* The TCP pseudo header checksum is always provided.
|
|
*/
|
|
if (tso) {
|
|
if (isipv6) {
|
|
m->m_pkthdr.csum_flags |= CSUM_TSO_IPV6;
|
|
} else {
|
|
m->m_pkthdr.csum_flags |= CSUM_TSO_IPV4;
|
|
}
|
|
|
|
m->m_pkthdr.tso_segsz = tp->t_maxopd - optlen;
|
|
} else {
|
|
m->m_pkthdr.tso_segsz = 0;
|
|
}
|
|
|
|
/*
|
|
* In transmit state, time the transmission and arrange for
|
|
* the retransmit. In persist state, just set snd_max.
|
|
*/
|
|
if (!(tp->t_flagsext & TF_FORCE)
|
|
|| tp->t_timer[TCPT_PERSIST] == 0) {
|
|
tcp_seq startseq = tp->snd_nxt;
|
|
|
|
/*
|
|
* Advance snd_nxt over sequence space of this segment.
|
|
*/
|
|
if (flags & (TH_SYN | TH_FIN)) {
|
|
if (flags & TH_SYN) {
|
|
tp->snd_nxt++;
|
|
}
|
|
if ((flags & TH_FIN) &&
|
|
!(tp->t_flags & TF_SENTFIN)) {
|
|
tp->snd_nxt++;
|
|
tp->t_flags |= TF_SENTFIN;
|
|
}
|
|
}
|
|
if (sack_rxmit) {
|
|
goto timer;
|
|
}
|
|
if (sack_rescue_rxt == TRUE) {
|
|
tp->snd_nxt = old_snd_nxt;
|
|
sack_rescue_rxt = FALSE;
|
|
tcpstat.tcps_pto_in_recovery++;
|
|
} else {
|
|
tp->snd_nxt += len;
|
|
}
|
|
if (SEQ_GT(tp->snd_nxt, tp->snd_max)) {
|
|
tp->snd_max = tp->snd_nxt;
|
|
tp->t_sndtime = tcp_now;
|
|
/*
|
|
* Time this transmission if not a retransmission and
|
|
* not currently timing anything.
|
|
*/
|
|
if (tp->t_rtttime == 0) {
|
|
tp->t_rtttime = tcp_now;
|
|
tp->t_rtseq = startseq;
|
|
tcpstat.tcps_segstimed++;
|
|
|
|
/* update variables related to pipe ack */
|
|
tp->t_pipeack_lastuna = tp->snd_una;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Set retransmit timer if not currently set,
|
|
* and not doing an ack or a keep-alive probe.
|
|
*/
|
|
timer:
|
|
if (tp->t_timer[TCPT_REXMT] == 0 &&
|
|
((sack_rxmit && tp->snd_nxt != tp->snd_max) ||
|
|
tp->snd_nxt != tp->snd_una || (flags & TH_FIN))) {
|
|
if (tp->t_timer[TCPT_PERSIST]) {
|
|
tp->t_timer[TCPT_PERSIST] = 0;
|
|
tp->t_persist_stop = 0;
|
|
TCP_RESET_REXMT_STATE(tp);
|
|
}
|
|
tp->t_timer[TCPT_REXMT] =
|
|
OFFSET_FROM_START(tp, tp->t_rxtcur);
|
|
}
|
|
|
|
/*
|
|
* Set tail loss probe timeout if new data is being
|
|
* transmitted. This will be supported only when
|
|
* SACK option is enabled on a connection.
|
|
*
|
|
* Every time new data is sent PTO will get reset.
|
|
*/
|
|
if (tcp_enable_tlp && len != 0 && tp->t_state == TCPS_ESTABLISHED &&
|
|
SACK_ENABLED(tp) && !IN_FASTRECOVERY(tp) &&
|
|
tp->snd_nxt == tp->snd_max &&
|
|
SEQ_GT(tp->snd_nxt, tp->snd_una) &&
|
|
tp->t_rxtshift == 0 &&
|
|
(tp->t_flagsext & (TF_SENT_TLPROBE | TF_PKTS_REORDERED)) == 0) {
|
|
uint32_t pto, srtt;
|
|
|
|
if (tcp_do_better_lr) {
|
|
srtt = tp->t_srtt >> TCP_RTT_SHIFT;
|
|
pto = 2 * srtt;
|
|
if ((tp->snd_max - tp->snd_una) <= tp->t_maxseg) {
|
|
pto += tcp_delack;
|
|
} else {
|
|
pto += 2;
|
|
}
|
|
} else {
|
|
/*
|
|
* Using SRTT alone to set PTO can cause spurious
|
|
* retransmissions on wireless networks where there
|
|
* is a lot of variance in RTT. Taking variance
|
|
* into account will avoid this.
|
|
*/
|
|
srtt = tp->t_srtt >> TCP_RTT_SHIFT;
|
|
pto = ((TCP_REXMTVAL(tp)) * 3) >> 1;
|
|
pto = max(2 * srtt, pto);
|
|
if ((tp->snd_max - tp->snd_una) == tp->t_maxseg) {
|
|
pto = max(pto,
|
|
(((3 * pto) >> 2) + tcp_delack * 2));
|
|
} else {
|
|
pto = max(10, pto);
|
|
}
|
|
}
|
|
|
|
/* if RTO is less than PTO, choose RTO instead */
|
|
if (tp->t_rxtcur < pto) {
|
|
pto = tp->t_rxtcur;
|
|
}
|
|
|
|
tp->t_timer[TCPT_PTO] = OFFSET_FROM_START(tp, pto);
|
|
}
|
|
} else {
|
|
/*
|
|
* Persist case, update snd_max but since we are in
|
|
* persist mode (no window) we do not update snd_nxt.
|
|
*/
|
|
int xlen = len;
|
|
if (flags & TH_SYN) {
|
|
++xlen;
|
|
}
|
|
if ((flags & TH_FIN) &&
|
|
!(tp->t_flags & TF_SENTFIN)) {
|
|
++xlen;
|
|
tp->t_flags |= TF_SENTFIN;
|
|
}
|
|
if (SEQ_GT(tp->snd_nxt + xlen, tp->snd_max)) {
|
|
tp->snd_max = tp->snd_nxt + len;
|
|
tp->t_sndtime = tcp_now;
|
|
}
|
|
}
|
|
|
|
#if TCPDEBUG
|
|
/*
|
|
* Trace.
|
|
*/
|
|
if (so_options & SO_DEBUG) {
|
|
tcp_trace(TA_OUTPUT, tp->t_state, tp, mtod(m, void *), th, 0);
|
|
}
|
|
#endif
|
|
|
|
/*
|
|
* Fill in IP length and desired time to live and
|
|
* send to IP level. There should be a better way
|
|
* to handle ttl and tos; we could keep them in
|
|
* the template, but need a way to checksum without them.
|
|
*/
|
|
/*
|
|
* m->m_pkthdr.len should have been set before cksum calcuration,
|
|
* because in6_cksum() need it.
|
|
*/
|
|
if (isipv6) {
|
|
/*
|
|
* we separately set hoplimit for every segment, since the
|
|
* user might want to change the value via setsockopt.
|
|
* Also, desired default hop limit might be changed via
|
|
* Neighbor Discovery.
|
|
*/
|
|
ip6->ip6_hlim = in6_selecthlim(inp, inp->in6p_route.ro_rt ?
|
|
inp->in6p_route.ro_rt->rt_ifp : NULL);
|
|
|
|
/* Don't set ECT bit if requested by an app */
|
|
|
|
/* Set ECN bits for testing purposes */
|
|
if (tp->ecn_flags & TE_FORCE_ECT1) {
|
|
ip6->ip6_flow |= htonl(IPTOS_ECN_ECT1 << 20);
|
|
} else if (tp->ecn_flags & TE_FORCE_ECT0) {
|
|
ip6->ip6_flow |= htonl(IPTOS_ECN_ECT0 << 20);
|
|
}
|
|
|
|
KERNEL_DEBUG(DBG_LAYER_BEG,
|
|
((inp->inp_fport << 16) | inp->inp_lport),
|
|
(((inp->in6p_laddr.s6_addr16[0] & 0xffff) << 16) |
|
|
(inp->in6p_faddr.s6_addr16[0] & 0xffff)),
|
|
sendalot, 0, 0);
|
|
} else {
|
|
ASSERT(m->m_pkthdr.len <= IP_MAXPACKET);
|
|
ip->ip_len = (u_short)m->m_pkthdr.len;
|
|
ip->ip_ttl = inp->inp_ip_ttl; /* XXX */
|
|
|
|
/* Don't set ECN bit if requested by an app */
|
|
ip->ip_tos |= (inp->inp_ip_tos & ~IPTOS_ECN_MASK);
|
|
|
|
/* Set ECN bits for testing purposes */
|
|
if (tp->ecn_flags & TE_FORCE_ECT1) {
|
|
ip->ip_tos |= IPTOS_ECN_ECT1;
|
|
} else if (tp->ecn_flags & TE_FORCE_ECT0) {
|
|
ip->ip_tos |= IPTOS_ECN_ECT0;
|
|
}
|
|
|
|
KERNEL_DEBUG(DBG_LAYER_BEG,
|
|
((inp->inp_fport << 16) | inp->inp_lport),
|
|
(((inp->inp_laddr.s_addr & 0xffff) << 16) |
|
|
(inp->inp_faddr.s_addr & 0xffff)), 0, 0, 0);
|
|
}
|
|
|
|
/*
|
|
* See if we should do MTU discovery.
|
|
* Look at the flag updated on the following criterias:
|
|
* 1) Path MTU discovery is authorized by the sysctl
|
|
* 2) The route isn't set yet (unlikely but could happen)
|
|
* 3) The route is up
|
|
* 4) the MTU is not locked (if it is, then discovery has been
|
|
* disabled for that route)
|
|
*/
|
|
if (!isipv6) {
|
|
if (path_mtu_discovery && (tp->t_flags & TF_PMTUD)) {
|
|
ip->ip_off |= IP_DF;
|
|
}
|
|
}
|
|
|
|
#if NECP
|
|
{
|
|
necp_kernel_policy_id policy_id;
|
|
necp_kernel_policy_id skip_policy_id;
|
|
u_int32_t route_rule_id;
|
|
u_int32_t pass_flags;
|
|
if (!necp_socket_is_allowed_to_send_recv(inp, NULL, 0, &policy_id, &route_rule_id, &skip_policy_id, &pass_flags)) {
|
|
TCP_LOG_DROP_NECP(isipv6 ? (void *)ip6 : (void *)ip, th, tp, true);
|
|
m_freem(m);
|
|
error = EHOSTUNREACH;
|
|
goto out;
|
|
}
|
|
necp_mark_packet_from_socket(m, inp, policy_id, route_rule_id, skip_policy_id, pass_flags);
|
|
|
|
if (net_qos_policy_restricted != 0) {
|
|
necp_socket_update_qos_marking(inp, inp->inp_route.ro_rt, route_rule_id);
|
|
}
|
|
}
|
|
#endif /* NECP */
|
|
|
|
#if IPSEC
|
|
if (inp->inp_sp != NULL) {
|
|
ipsec_setsocket(m, so);
|
|
}
|
|
#endif /*IPSEC*/
|
|
|
|
/*
|
|
* The socket is kept locked while sending out packets in ip_output, even if packet chaining is not active.
|
|
*/
|
|
lost = 0;
|
|
|
|
/*
|
|
* Embed the flow hash in pkt hdr and mark the packet as
|
|
* capable of flow controlling
|
|
*/
|
|
m->m_pkthdr.pkt_flowsrc = FLOWSRC_INPCB;
|
|
m->m_pkthdr.pkt_flowid = inp->inp_flowhash;
|
|
m->m_pkthdr.pkt_flags |= (PKTF_FLOW_ID | PKTF_FLOW_LOCALSRC | PKTF_FLOW_ADV);
|
|
m->m_pkthdr.pkt_proto = IPPROTO_TCP;
|
|
m->m_pkthdr.tx_tcp_pid = so->last_pid;
|
|
if (so->so_flags & SOF_DELEGATED) {
|
|
m->m_pkthdr.tx_tcp_e_pid = so->e_pid;
|
|
} else {
|
|
m->m_pkthdr.tx_tcp_e_pid = 0;
|
|
}
|
|
|
|
m->m_nextpkt = NULL;
|
|
|
|
if (inp->inp_last_outifp != NULL &&
|
|
!(inp->inp_last_outifp->if_flags & IFF_LOOPBACK)) {
|
|
/* Hint to prioritize this packet if
|
|
* 1. if the packet has no data
|
|
* 2. the interface supports transmit-start model and did
|
|
* not disable ACK prioritization.
|
|
* 3. Only ACK flag is set.
|
|
* 4. there is no outstanding data on this connection.
|
|
*/
|
|
if (len == 0 && (inp->inp_last_outifp->if_eflags & (IFEF_TXSTART | IFEF_NOACKPRI)) == IFEF_TXSTART) {
|
|
if (th->th_flags == TH_ACK &&
|
|
tp->snd_una == tp->snd_max &&
|
|
tp->t_timer[TCPT_REXMT] == 0) {
|
|
svc_flags |= PKT_SCF_TCP_ACK;
|
|
}
|
|
if (th->th_flags & TH_SYN) {
|
|
svc_flags |= PKT_SCF_TCP_SYN;
|
|
}
|
|
}
|
|
set_packet_service_class(m, so, sotc, svc_flags);
|
|
} else {
|
|
/*
|
|
* Optimization for loopback just set the mbuf
|
|
* service class
|
|
*/
|
|
(void) m_set_service_class(m, so_tc2msc(sotc));
|
|
}
|
|
|
|
if ((th->th_flags & TH_SYN) && tp->t_syn_sent < UINT8_MAX) {
|
|
tp->t_syn_sent++;
|
|
}
|
|
if ((th->th_flags & TH_FIN) && tp->t_fin_sent < UINT8_MAX) {
|
|
tp->t_fin_sent++;
|
|
}
|
|
if ((th->th_flags & TH_RST) && tp->t_rst_sent < UINT8_MAX) {
|
|
tp->t_rst_sent++;
|
|
}
|
|
TCP_LOG_TH_FLAGS(isipv6 ? (void *)ip6 : (void *)ip, th, tp, true,
|
|
inp->inp_last_outifp != NULL ? inp->inp_last_outifp :
|
|
inp->inp_boundifp);
|
|
|
|
tp->t_pktlist_sentlen += len;
|
|
tp->t_lastchain++;
|
|
|
|
if (isipv6) {
|
|
DTRACE_TCP5(send, struct mbuf *, m, struct inpcb *, inp,
|
|
struct ip6 *, ip6, struct tcpcb *, tp, struct tcphdr *,
|
|
th);
|
|
} else {
|
|
DTRACE_TCP5(send, struct mbuf *, m, struct inpcb *, inp,
|
|
struct ip *, ip, struct tcpcb *, tp, struct tcphdr *, th);
|
|
}
|
|
|
|
if (tp->t_pktlist_head != NULL) {
|
|
tp->t_pktlist_tail->m_nextpkt = m;
|
|
tp->t_pktlist_tail = m;
|
|
} else {
|
|
packchain_newlist++;
|
|
tp->t_pktlist_head = tp->t_pktlist_tail = m;
|
|
}
|
|
|
|
if (sendalot == 0 || (tp->t_state != TCPS_ESTABLISHED) ||
|
|
(tp->t_flags & TF_ACKNOW) ||
|
|
(tp->t_flagsext & TF_FORCE) ||
|
|
tp->t_lastchain >= tcp_packet_chaining) {
|
|
error = 0;
|
|
while (inp->inp_sndinprog_cnt == 0 &&
|
|
tp->t_pktlist_head != NULL) {
|
|
packetlist = tp->t_pktlist_head;
|
|
packchain_listadd = tp->t_lastchain;
|
|
packchain_sent++;
|
|
lost = tp->t_pktlist_sentlen;
|
|
TCP_PKTLIST_CLEAR(tp);
|
|
|
|
error = tcp_ip_output(so, tp, packetlist,
|
|
packchain_listadd, tp_inp_options,
|
|
(so_options & SO_DONTROUTE),
|
|
(sack_rxmit || (sack_bytes_rxmt != 0)), isipv6);
|
|
if (error) {
|
|
/*
|
|
* Take into account the rest of unsent
|
|
* packets in the packet list for this tcp
|
|
* into "lost", since we're about to free
|
|
* the whole list below.
|
|
*/
|
|
lost += tp->t_pktlist_sentlen;
|
|
break;
|
|
} else {
|
|
lost = 0;
|
|
}
|
|
}
|
|
/* tcp was closed while we were in ip; resume close */
|
|
if (inp->inp_sndinprog_cnt == 0 &&
|
|
(tp->t_flags & TF_CLOSING)) {
|
|
tp->t_flags &= ~TF_CLOSING;
|
|
(void) tcp_close(tp);
|
|
return 0;
|
|
}
|
|
} else {
|
|
error = 0;
|
|
packchain_looped++;
|
|
tcpstat.tcps_sndtotal++;
|
|
|
|
goto again;
|
|
}
|
|
if (error) {
|
|
/*
|
|
* Assume that the packets were lost, so back out the
|
|
* sequence number advance, if any. Note that the "lost"
|
|
* variable represents the amount of user data sent during
|
|
* the recent call to ip_output_list() plus the amount of
|
|
* user data in the packet list for this tcp at the moment.
|
|
*/
|
|
if (!(tp->t_flagsext & TF_FORCE)
|
|
|| tp->t_timer[TCPT_PERSIST] == 0) {
|
|
/*
|
|
* No need to check for TH_FIN here because
|
|
* the TF_SENTFIN flag handles that case.
|
|
*/
|
|
if ((flags & TH_SYN) == 0) {
|
|
if (sack_rxmit) {
|
|
if (SEQ_GT((p->rxmit - lost),
|
|
tp->snd_una)) {
|
|
p->rxmit -= lost;
|
|
|
|
if (SEQ_LT(p->rxmit, p->start)) {
|
|
p->rxmit = p->start;
|
|
}
|
|
} else {
|
|
lost = p->rxmit - tp->snd_una;
|
|
p->rxmit = tp->snd_una;
|
|
|
|
if (SEQ_LT(p->rxmit, p->start)) {
|
|
p->rxmit = p->start;
|
|
}
|
|
}
|
|
tp->sackhint.sack_bytes_rexmit -= lost;
|
|
if (tp->sackhint.sack_bytes_rexmit < 0) {
|
|
tp->sackhint.sack_bytes_rexmit = 0;
|
|
}
|
|
} else {
|
|
if (SEQ_GT((tp->snd_nxt - lost),
|
|
tp->snd_una)) {
|
|
tp->snd_nxt -= lost;
|
|
} else {
|
|
tp->snd_nxt = tp->snd_una;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
out:
|
|
if (tp->t_pktlist_head != NULL) {
|
|
m_freem_list(tp->t_pktlist_head);
|
|
}
|
|
TCP_PKTLIST_CLEAR(tp);
|
|
|
|
if (error == ENOBUFS) {
|
|
/*
|
|
* Set retransmit timer if not currently set
|
|
* when we failed to send a segment that can be
|
|
* retransmitted (i.e. not pure ack or rst)
|
|
*/
|
|
if (tp->t_timer[TCPT_REXMT] == 0 &&
|
|
tp->t_timer[TCPT_PERSIST] == 0 &&
|
|
(len != 0 || (flags & (TH_SYN | TH_FIN)) != 0 ||
|
|
so->so_snd.sb_cc > 0)) {
|
|
tp->t_timer[TCPT_REXMT] =
|
|
OFFSET_FROM_START(tp, tp->t_rxtcur);
|
|
}
|
|
tp->snd_cwnd = tp->t_maxseg;
|
|
tp->t_bytes_acked = 0;
|
|
tcp_check_timer_state(tp);
|
|
KERNEL_DEBUG(DBG_FNC_TCP_OUTPUT | DBG_FUNC_END, 0, 0, 0, 0, 0);
|
|
|
|
TCP_LOG_OUTPUT(tp, "error ENOBUFS silently handled");
|
|
|
|
tcp_ccdbg_trace(tp, NULL, TCP_CC_OUTPUT_ERROR);
|
|
return 0;
|
|
}
|
|
if (error == EMSGSIZE) {
|
|
/*
|
|
* ip_output() will have already fixed the route
|
|
* for us. tcp_mtudisc() will, as its last action,
|
|
* initiate retransmission, so it is important to
|
|
* not do so here.
|
|
*
|
|
* If TSO was active we either got an interface
|
|
* without TSO capabilits or TSO was turned off.
|
|
* Disable it for this connection as too and
|
|
* immediatly retry with MSS sized segments generated
|
|
* by this function.
|
|
*/
|
|
if (tso) {
|
|
tp->t_flags &= ~TF_TSO;
|
|
}
|
|
|
|
tcp_mtudisc(inp, 0);
|
|
tcp_check_timer_state(tp);
|
|
|
|
TCP_LOG_OUTPUT(tp, "error EMSGSIZE silently handled");
|
|
|
|
KERNEL_DEBUG(DBG_FNC_TCP_OUTPUT | DBG_FUNC_END, 0, 0, 0, 0, 0);
|
|
return 0;
|
|
}
|
|
/*
|
|
* Unless this is due to interface restriction policy,
|
|
* treat EHOSTUNREACH/ENETDOWN/EADDRNOTAVAIL as a soft error.
|
|
*/
|
|
if ((error == EHOSTUNREACH || error == ENETDOWN || error == EADDRNOTAVAIL) &&
|
|
TCPS_HAVERCVDSYN(tp->t_state) &&
|
|
!inp_restricted_send(inp, inp->inp_last_outifp)) {
|
|
tp->t_softerror = error;
|
|
TCP_LOG_OUTPUT(tp, "soft error %d silently handled", error);
|
|
error = 0;
|
|
} else {
|
|
TCP_LOG_OUTPUT(tp, "error %d", error);
|
|
}
|
|
tcp_check_timer_state(tp);
|
|
KERNEL_DEBUG(DBG_FNC_TCP_OUTPUT | DBG_FUNC_END, 0, 0, 0, 0, 0);
|
|
return error;
|
|
}
|
|
|
|
tcpstat.tcps_sndtotal++;
|
|
|
|
KERNEL_DEBUG(DBG_FNC_TCP_OUTPUT | DBG_FUNC_END, 0, 0, 0, 0, 0);
|
|
if (sendalot) {
|
|
goto again;
|
|
}
|
|
|
|
tcp_check_timer_state(tp);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int
|
|
tcp_ip_output(struct socket *so, struct tcpcb *tp, struct mbuf *pkt,
|
|
int cnt, struct mbuf *opt, int flags, int sack_in_progress, boolean_t isipv6)
|
|
{
|
|
int error = 0;
|
|
boolean_t chain;
|
|
boolean_t unlocked = FALSE;
|
|
boolean_t ifdenied = FALSE;
|
|
struct inpcb *inp = tp->t_inpcb;
|
|
struct ifnet *outif = NULL;
|
|
bool check_qos_marking_again = (so->so_flags1 & SOF1_QOSMARKING_POLICY_OVERRIDE) ? FALSE : TRUE;
|
|
|
|
union {
|
|
struct route _ro;
|
|
struct route_in6 _ro6;
|
|
} route_u_ = {};
|
|
#define ro route_u_._ro
|
|
#define ro6 route_u_._ro6
|
|
|
|
union {
|
|
struct ip_out_args _ipoa;
|
|
struct ip6_out_args _ip6oa;
|
|
} out_args_u_ = {};
|
|
#define ipoa out_args_u_._ipoa
|
|
#define ip6oa out_args_u_._ip6oa
|
|
|
|
if (isipv6) {
|
|
ip6oa.ip6oa_boundif = IFSCOPE_NONE;
|
|
ip6oa.ip6oa_flags = IP6OAF_SELECT_SRCIF | IP6OAF_BOUND_SRCADDR;
|
|
ip6oa.ip6oa_sotc = SO_TC_UNSPEC;
|
|
ip6oa.ip6oa_netsvctype = _NET_SERVICE_TYPE_UNSPEC;
|
|
} else {
|
|
ipoa.ipoa_boundif = IFSCOPE_NONE;
|
|
ipoa.ipoa_flags = IPOAF_SELECT_SRCIF | IPOAF_BOUND_SRCADDR;
|
|
ipoa.ipoa_sotc = SO_TC_UNSPEC;
|
|
ipoa.ipoa_netsvctype = _NET_SERVICE_TYPE_UNSPEC;
|
|
}
|
|
|
|
struct flowadv *adv =
|
|
(isipv6 ? &ip6oa.ip6oa_flowadv : &ipoa.ipoa_flowadv);
|
|
|
|
/* If socket was bound to an ifindex, tell ip_output about it */
|
|
if (inp->inp_flags & INP_BOUND_IF) {
|
|
if (isipv6) {
|
|
ip6oa.ip6oa_boundif = inp->inp_boundifp->if_index;
|
|
ip6oa.ip6oa_flags |= IP6OAF_BOUND_IF;
|
|
} else {
|
|
ipoa.ipoa_boundif = inp->inp_boundifp->if_index;
|
|
ipoa.ipoa_flags |= IPOAF_BOUND_IF;
|
|
}
|
|
} else if (!in6_embedded_scope && isipv6 && (IN6_IS_SCOPE_EMBED(&inp->in6p_faddr))) {
|
|
ip6oa.ip6oa_boundif = inp->inp_fifscope;
|
|
ip6oa.ip6oa_flags |= IP6OAF_BOUND_IF;
|
|
}
|
|
|
|
if (INP_NO_CELLULAR(inp)) {
|
|
if (isipv6) {
|
|
ip6oa.ip6oa_flags |= IP6OAF_NO_CELLULAR;
|
|
} else {
|
|
ipoa.ipoa_flags |= IPOAF_NO_CELLULAR;
|
|
}
|
|
}
|
|
if (INP_NO_EXPENSIVE(inp)) {
|
|
if (isipv6) {
|
|
ip6oa.ip6oa_flags |= IP6OAF_NO_EXPENSIVE;
|
|
} else {
|
|
ipoa.ipoa_flags |= IPOAF_NO_EXPENSIVE;
|
|
}
|
|
}
|
|
if (INP_NO_CONSTRAINED(inp)) {
|
|
if (isipv6) {
|
|
ip6oa.ip6oa_flags |= IP6OAF_NO_CONSTRAINED;
|
|
} else {
|
|
ipoa.ipoa_flags |= IPOAF_NO_CONSTRAINED;
|
|
}
|
|
}
|
|
if (INP_AWDL_UNRESTRICTED(inp)) {
|
|
if (isipv6) {
|
|
ip6oa.ip6oa_flags |= IP6OAF_AWDL_UNRESTRICTED;
|
|
} else {
|
|
ipoa.ipoa_flags |= IPOAF_AWDL_UNRESTRICTED;
|
|
}
|
|
}
|
|
if (INP_INTCOPROC_ALLOWED(inp) && isipv6) {
|
|
ip6oa.ip6oa_flags |= IP6OAF_INTCOPROC_ALLOWED;
|
|
}
|
|
if (INP_MANAGEMENT_ALLOWED(inp)) {
|
|
if (isipv6) {
|
|
ip6oa.ip6oa_flags |= IP6OAF_MANAGEMENT_ALLOWED;
|
|
} else {
|
|
ipoa.ipoa_flags |= IPOAF_MANAGEMENT_ALLOWED;
|
|
}
|
|
}
|
|
if (isipv6) {
|
|
ip6oa.ip6oa_sotc = so->so_traffic_class;
|
|
ip6oa.ip6oa_netsvctype = so->so_netsvctype;
|
|
ip6oa.qos_marking_gencount = inp->inp_policyresult.results.qos_marking_gencount;
|
|
} else {
|
|
ipoa.ipoa_sotc = so->so_traffic_class;
|
|
ipoa.ipoa_netsvctype = so->so_netsvctype;
|
|
ipoa.qos_marking_gencount = inp->inp_policyresult.results.qos_marking_gencount;
|
|
}
|
|
if ((so->so_flags1 & SOF1_QOSMARKING_ALLOWED)) {
|
|
if (isipv6) {
|
|
ip6oa.ip6oa_flags |= IP6OAF_QOSMARKING_ALLOWED;
|
|
} else {
|
|
ipoa.ipoa_flags |= IPOAF_QOSMARKING_ALLOWED;
|
|
}
|
|
}
|
|
if (check_qos_marking_again) {
|
|
if (isipv6) {
|
|
ip6oa.ip6oa_flags |= IP6OAF_REDO_QOSMARKING_POLICY;
|
|
} else {
|
|
ipoa.ipoa_flags |= IPOAF_REDO_QOSMARKING_POLICY;
|
|
}
|
|
}
|
|
if (isipv6) {
|
|
flags |= IPV6_OUTARGS;
|
|
} else {
|
|
flags |= IP_OUTARGS;
|
|
}
|
|
|
|
/* Copy the cached route and take an extra reference */
|
|
if (isipv6) {
|
|
in6p_route_copyout(inp, &ro6);
|
|
} else {
|
|
inp_route_copyout(inp, &ro);
|
|
}
|
|
#if (DEBUG || DEVELOPMENT)
|
|
if ((so->so_flags & SOF_MARK_WAKE_PKT) && pkt != NULL) {
|
|
so->so_flags &= ~SOF_MARK_WAKE_PKT;
|
|
pkt->m_pkthdr.pkt_flags |= PKTF_WAKE_PKT;
|
|
}
|
|
#endif /* (DEBUG || DEVELOPMENT) */
|
|
|
|
/*
|
|
* Make sure ACK/DELACK conditions are cleared before
|
|
* we unlock the socket.
|
|
*/
|
|
tp->last_ack_sent = tp->rcv_nxt;
|
|
tp->t_flags &= ~(TF_ACKNOW | TF_DELACK);
|
|
tp->t_timer[TCPT_DELACK] = 0;
|
|
tp->t_unacksegs = 0;
|
|
tp->t_unacksegs_ce = 0;
|
|
|
|
/* Increment the count of outstanding send operations */
|
|
inp->inp_sndinprog_cnt++;
|
|
|
|
/*
|
|
* If allowed, unlock TCP socket while in IP
|
|
* but only if the connection is established and
|
|
* in a normal mode where reentrancy on the tcpcb won't be
|
|
* an issue:
|
|
* - there is no SACK episode
|
|
* - we're not in Fast Recovery mode
|
|
* - if we're not sending from an upcall.
|
|
*/
|
|
if (tcp_output_unlocked && !so->so_upcallusecount &&
|
|
(tp->t_state == TCPS_ESTABLISHED) && (sack_in_progress == 0) &&
|
|
!IN_FASTRECOVERY(tp) && !(so->so_flags & SOF_MP_SUBFLOW)) {
|
|
unlocked = TRUE;
|
|
socket_unlock(so, 0);
|
|
}
|
|
|
|
/*
|
|
* Don't send down a chain of packets when:
|
|
* - TCP chaining is disabled
|
|
* - there is an IPsec rule set
|
|
* - there is a non default rule set for the firewall
|
|
*/
|
|
|
|
chain = tcp_packet_chaining > 1
|
|
#if IPSEC
|
|
&& ipsec_bypass
|
|
#endif
|
|
; // I'm important, not extraneous
|
|
|
|
while (pkt != NULL) {
|
|
struct mbuf *npkt = pkt->m_nextpkt;
|
|
|
|
if (!chain) {
|
|
pkt->m_nextpkt = NULL;
|
|
/*
|
|
* If we are not chaining, make sure to set the packet
|
|
* list count to 0 so that IP takes the right path;
|
|
* this is important for cases such as IPsec where a
|
|
* single mbuf might result in multiple mbufs as part
|
|
* of the encapsulation. If a non-zero count is passed
|
|
* down to IP, the head of the chain might change and
|
|
* we could end up skipping it (thus generating bogus
|
|
* packets). Fixing it in IP would be desirable, but
|
|
* for now this would do it.
|
|
*/
|
|
cnt = 0;
|
|
}
|
|
if (isipv6) {
|
|
error = ip6_output_list(pkt, cnt,
|
|
inp->in6p_outputopts, &ro6, flags, NULL, NULL,
|
|
&ip6oa);
|
|
ifdenied = (ip6oa.ip6oa_flags & IP6OAF_R_IFDENIED);
|
|
} else {
|
|
error = ip_output_list(pkt, cnt, opt, &ro, flags, NULL,
|
|
&ipoa);
|
|
ifdenied = (ipoa.ipoa_flags & IPOAF_R_IFDENIED);
|
|
}
|
|
|
|
if (chain || error) {
|
|
/*
|
|
* If we sent down a chain then we are done since
|
|
* the callee had taken care of everything; else
|
|
* we need to free the rest of the chain ourselves.
|
|
*/
|
|
if (!chain) {
|
|
m_freem_list(npkt);
|
|
}
|
|
break;
|
|
}
|
|
pkt = npkt;
|
|
}
|
|
|
|
if (unlocked) {
|
|
socket_lock(so, 0);
|
|
}
|
|
|
|
/*
|
|
* Enter flow controlled state if the connection is established
|
|
* and is not in recovery. Flow control is allowed only if there
|
|
* is outstanding data.
|
|
*
|
|
* A connection will enter suspended state even if it is in
|
|
* recovery.
|
|
*/
|
|
if (((adv->code == FADV_FLOW_CONTROLLED && !IN_FASTRECOVERY(tp)) ||
|
|
adv->code == FADV_SUSPENDED) &&
|
|
!(tp->t_flags & TF_CLOSING) &&
|
|
tp->t_state == TCPS_ESTABLISHED &&
|
|
SEQ_GT(tp->snd_max, tp->snd_una)) {
|
|
int rc;
|
|
rc = inp_set_fc_state(inp, adv->code);
|
|
|
|
if (rc == 1) {
|
|
tcp_ccdbg_trace(tp, NULL,
|
|
((adv->code == FADV_FLOW_CONTROLLED) ?
|
|
TCP_CC_FLOW_CONTROL : TCP_CC_SUSPEND));
|
|
if (adv->code == FADV_FLOW_CONTROLLED) {
|
|
TCP_LOG_OUTPUT(tp, "flow controlled");
|
|
} else {
|
|
TCP_LOG_OUTPUT(tp, "flow suspended");
|
|
}
|
|
}
|
|
}
|
|
|
|
/*
|
|
* When an interface queue gets suspended, some of the
|
|
* packets are dropped. Return ENOBUFS, to update the
|
|
* pcb state.
|
|
*/
|
|
if (adv->code == FADV_SUSPENDED) {
|
|
error = ENOBUFS;
|
|
}
|
|
|
|
VERIFY(inp->inp_sndinprog_cnt > 0);
|
|
if (--inp->inp_sndinprog_cnt == 0) {
|
|
inp->inp_flags &= ~(INP_FC_FEEDBACK);
|
|
if (inp->inp_sndingprog_waiters > 0) {
|
|
wakeup(&inp->inp_sndinprog_cnt);
|
|
}
|
|
}
|
|
|
|
if (isipv6) {
|
|
/*
|
|
* When an NECP IP tunnel policy forces the outbound interface,
|
|
* ip6_output_list() informs the transport layer what is the actual
|
|
* outgoing interface
|
|
*/
|
|
if (ip6oa.ip6oa_flags & IP6OAF_BOUND_IF) {
|
|
outif = ifindex2ifnet[ip6oa.ip6oa_boundif];
|
|
} else if (ro6.ro_rt != NULL) {
|
|
outif = ro6.ro_rt->rt_ifp;
|
|
}
|
|
} else {
|
|
if (ro.ro_rt != NULL) {
|
|
outif = ro.ro_rt->rt_ifp;
|
|
}
|
|
}
|
|
if (check_qos_marking_again) {
|
|
uint32_t qos_marking_gencount;
|
|
bool allow_qos_marking;
|
|
if (isipv6) {
|
|
qos_marking_gencount = ip6oa.qos_marking_gencount;
|
|
allow_qos_marking = ip6oa.ip6oa_flags & IP6OAF_QOSMARKING_ALLOWED ? TRUE : FALSE;
|
|
} else {
|
|
qos_marking_gencount = ipoa.qos_marking_gencount;
|
|
allow_qos_marking = ipoa.ipoa_flags & IPOAF_QOSMARKING_ALLOWED ? TRUE : FALSE;
|
|
}
|
|
inp->inp_policyresult.results.qos_marking_gencount = qos_marking_gencount;
|
|
if (allow_qos_marking == TRUE) {
|
|
inp->inp_socket->so_flags1 |= SOF1_QOSMARKING_ALLOWED;
|
|
} else {
|
|
inp->inp_socket->so_flags1 &= ~SOF1_QOSMARKING_ALLOWED;
|
|
}
|
|
}
|
|
|
|
if (outif != NULL && outif != inp->inp_last_outifp) {
|
|
/* Update the send byte count */
|
|
if (so->so_snd.sb_cc > 0 && so->so_snd.sb_flags & SB_SNDBYTE_CNT) {
|
|
inp_decr_sndbytes_total(so, so->so_snd.sb_cc);
|
|
inp_decr_sndbytes_allunsent(so, tp->snd_una);
|
|
so->so_snd.sb_flags &= ~SB_SNDBYTE_CNT;
|
|
}
|
|
inp->inp_last_outifp = outif;
|
|
#if SKYWALK
|
|
if (NETNS_TOKEN_VALID(&inp->inp_netns_token)) {
|
|
netns_set_ifnet(&inp->inp_netns_token, inp->inp_last_outifp);
|
|
}
|
|
#endif /* SKYWALK */
|
|
}
|
|
|
|
if (error != 0 && ifdenied &&
|
|
(INP_NO_CELLULAR(inp) || INP_NO_EXPENSIVE(inp) || INP_NO_CONSTRAINED(inp))) {
|
|
soevent(so,
|
|
(SO_FILT_HINT_LOCKED | SO_FILT_HINT_IFDENIED));
|
|
}
|
|
|
|
/* Synchronize cached PCB route & options */
|
|
if (isipv6) {
|
|
in6p_route_copyin(inp, &ro6);
|
|
} else {
|
|
inp_route_copyin(inp, &ro);
|
|
}
|
|
|
|
if (tp->t_state < TCPS_ESTABLISHED && tp->t_rxtshift == 0 &&
|
|
tp->t_inpcb->inp_route.ro_rt != NULL) {
|
|
/* If we found the route and there is an rtt on it
|
|
* reset the retransmit timer
|
|
*/
|
|
tcp_getrt_rtt(tp, tp->t_inpcb->in6p_route.ro_rt);
|
|
tp->t_timer[TCPT_REXMT] = OFFSET_FROM_START(tp, tp->t_rxtcur);
|
|
}
|
|
return error;
|
|
#undef ro
|
|
#undef ro6
|
|
#undef ipoa
|
|
#undef ip6oa
|
|
}
|
|
|
|
int tcptv_persmin_val = TCPTV_PERSMIN;
|
|
|
|
void
|
|
tcp_setpersist(struct tcpcb *tp)
|
|
{
|
|
int t = ((tp->t_srtt >> 2) + tp->t_rttvar) >> 1;
|
|
|
|
/* If a PERSIST_TIMER option was set we will limit the
|
|
* time the persist timer will be active for that connection
|
|
* in order to avoid DOS by using zero window probes.
|
|
* see rdar://5805356
|
|
*/
|
|
|
|
if (tp->t_persist_timeout != 0 &&
|
|
tp->t_timer[TCPT_PERSIST] == 0 &&
|
|
tp->t_persist_stop == 0) {
|
|
tp->t_persist_stop = tcp_now + tp->t_persist_timeout;
|
|
}
|
|
|
|
/*
|
|
* Start/restart persistance timer.
|
|
*/
|
|
TCPT_RANGESET(tp->t_timer[TCPT_PERSIST],
|
|
t * tcp_backoff[tp->t_rxtshift],
|
|
tcptv_persmin_val, TCPTV_PERSMAX, 0);
|
|
tp->t_timer[TCPT_PERSIST] = OFFSET_FROM_START(tp, tp->t_timer[TCPT_PERSIST]);
|
|
|
|
if (tp->t_rxtshift < TCP_MAXRXTSHIFT) {
|
|
tp->t_rxtshift++;
|
|
}
|
|
}
|
|
|
|
static int
|
|
tcp_recv_throttle(struct tcpcb *tp)
|
|
{
|
|
uint32_t base_rtt, newsize;
|
|
struct sockbuf *sbrcv = &tp->t_inpcb->inp_socket->so_rcv;
|
|
|
|
if (tcp_use_rtt_recvbg == 1 &&
|
|
TSTMP_SUPPORTED(tp)) {
|
|
/*
|
|
* Timestamps are supported on this connection. Use
|
|
* RTT to look for an increase in latency.
|
|
*/
|
|
|
|
/*
|
|
* If the connection is already being throttled, leave it
|
|
* in that state until rtt comes closer to base rtt
|
|
*/
|
|
if (tp->t_flagsext & TF_RECV_THROTTLE) {
|
|
return 1;
|
|
}
|
|
|
|
base_rtt = get_base_rtt(tp);
|
|
|
|
if (base_rtt != 0 && tp->t_rttcur != 0) {
|
|
/*
|
|
* if latency increased on a background flow,
|
|
* return 1 to start throttling.
|
|
*/
|
|
if (tp->t_rttcur > (base_rtt + target_qdelay)) {
|
|
tp->t_flagsext |= TF_RECV_THROTTLE;
|
|
if (tp->t_recv_throttle_ts == 0) {
|
|
tp->t_recv_throttle_ts = tcp_now;
|
|
}
|
|
/*
|
|
* Reduce the recv socket buffer size to
|
|
* minimize latecy.
|
|
*/
|
|
if (sbrcv->sb_idealsize >
|
|
tcp_recv_throttle_minwin) {
|
|
newsize = sbrcv->sb_idealsize >> 1;
|
|
/* Set a minimum of 16 K */
|
|
newsize =
|
|
max(newsize,
|
|
tcp_recv_throttle_minwin);
|
|
sbrcv->sb_idealsize = newsize;
|
|
}
|
|
return 1;
|
|
} else {
|
|
return 0;
|
|
}
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Timestamps are not supported or there is no good RTT
|
|
* measurement. Use IPDV in this case.
|
|
*/
|
|
if (tp->acc_iaj > tcp_acc_iaj_react_limit) {
|
|
return 1;
|
|
}
|
|
|
|
return 0;
|
|
}
|