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gems-kernel/source/THIRDPARTY/xnu/bsd/netinet/ip_input.c

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add darwin/xnu functionality
2024-06-03 16:29:39 +00:00
/*
* Copyright (c) 2000-2021 Apple Inc. All rights reserved.
*
* @APPLE_OSREFERENCE_LICENSE_HEADER_START@
*
* This file contains Original Code and/or Modifications of Original Code
* as defined in and that are subject to the Apple Public Source License
* Version 2.0 (the 'License'). You may not use this file except in
* compliance with the License. The rights granted to you under the License
* may not be used to create, or enable the creation or redistribution of,
* unlawful or unlicensed copies of an Apple operating system, or to
* circumvent, violate, or enable the circumvention or violation of, any
* terms of an Apple operating system software license agreement.
*
* Please obtain a copy of the License at
* http://www.opensource.apple.com/apsl/ and read it before using this file.
*
* The Original Code and all software distributed under the License are
* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
* Please see the License for the specific language governing rights and
* limitations under the License.
*
* @APPLE_OSREFERENCE_LICENSE_HEADER_END@
*/
/*
* Copyright (c) 1982, 1986, 1988, 1993
* The Regents of the University of California. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)ip_input.c 8.2 (Berkeley) 1/4/94
*/
/*
* NOTICE: This file was modified by SPARTA, Inc. in 2007 to introduce
* support for mandatory and extensible security protections. This notice
* is included in support of clause 2.2 (b) of the Apple Public License,
* Version 2.0.
*/
#define _IP_VHL
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/mbuf.h>
#include <sys/malloc.h>
#include <sys/domain.h>
#include <sys/protosw.h>
#include <sys/socket.h>
#include <sys/time.h>
#include <sys/kernel.h>
#include <sys/syslog.h>
#include <sys/sysctl.h>
#include <sys/mcache.h>
#include <sys/socketvar.h>
#include <sys/kdebug.h>
#include <mach/mach_time.h>
#include <mach/sdt.h>
#include <machine/endian.h>
#include <dev/random/randomdev.h>
#include <kern/queue.h>
#include <kern/locks.h>
#include <libkern/OSAtomic.h>
#include <pexpert/pexpert.h>
#include <net/if.h>
#include <net/if_var.h>
#include <net/if_dl.h>
#include <net/route.h>
#include <net/kpi_protocol.h>
#include <net/ntstat.h>
#include <net/dlil.h>
#include <net/classq/classq.h>
#include <net/net_perf.h>
#include <net/init.h>
#if PF
#include <net/pfvar.h>
#endif /* PF */
#include <net/if_ports_used.h>
#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/in_var.h>
#include <netinet/in_arp.h>
#include <netinet/ip.h>
#include <netinet/in_pcb.h>
#include <netinet/ip_var.h>
#include <netinet/ip_icmp.h>
#include <netinet/kpi_ipfilter_var.h>
#include <netinet/udp.h>
#include <netinet/udp_var.h>
#include <netinet/bootp.h>
#if DUMMYNET
#include <netinet/ip_dummynet.h>
#endif /* DUMMYNET */
#if IPSEC
#include <netinet6/ipsec.h>
#include <netkey/key.h>
#endif /* IPSEC */
#include <net/sockaddr_utils.h>
#include <os/log.h>
#define DBG_LAYER_BEG NETDBG_CODE(DBG_NETIP, 0)
#define DBG_LAYER_END NETDBG_CODE(DBG_NETIP, 2)
#define DBG_FNC_IP_INPUT NETDBG_CODE(DBG_NETIP, (2 << 8))
#if IPSEC
extern int ipsec_bypass;
#endif /* IPSEC */
MBUFQ_HEAD(fq_head);
static int frag_timeout_run; /* frag timer is scheduled to run */
static void frag_timeout(void *);
static void frag_sched_timeout(void);
static struct ipq *ipq_alloc(void);
static void ipq_free(struct ipq *);
static void ipq_updateparams(void);
static void ip_input_second_pass(struct mbuf *, struct ifnet *,
int, int, struct ip_fw_in_args *);
static LCK_GRP_DECLARE(ipqlock_grp, "ipqlock");
static LCK_MTX_DECLARE(ipqlock, &ipqlock_grp);
/* Packet reassembly stuff */
#define IPREASS_NHASH_LOG2 6
#define IPREASS_NHASH (1 << IPREASS_NHASH_LOG2)
#define IPREASS_HMASK (IPREASS_NHASH - 1)
#define IPREASS_HASH(x, y) \
(((((x) & 0xF) | ((((x) >> 8) & 0xF) << 4)) ^ (y)) & IPREASS_HMASK)
/* IP fragment reassembly queues (protected by ipqlock) */
static TAILQ_HEAD(ipqhead, ipq) ipq[IPREASS_NHASH]; /* ip reassembly queues */
static int maxnipq; /* max packets in reass queues */
static u_int32_t maxfragsperpacket; /* max frags/packet in reass queues */
static u_int32_t nipq; /* # of packets in reass queues */
static u_int32_t ipq_limit; /* ipq allocation limit */
static u_int32_t ipq_count; /* current # of allocated ipq's */
static int sysctl_ipforwarding SYSCTL_HANDLER_ARGS;
static int sysctl_maxnipq SYSCTL_HANDLER_ARGS;
static int sysctl_maxfragsperpacket SYSCTL_HANDLER_ARGS;
#if (DEBUG || DEVELOPMENT)
static int sysctl_reset_ip_input_stats SYSCTL_HANDLER_ARGS;
static int sysctl_ip_input_measure_bins SYSCTL_HANDLER_ARGS;
static int sysctl_ip_input_getperf SYSCTL_HANDLER_ARGS;
#endif /* (DEBUG || DEVELOPMENT) */
int ipforwarding = 0;
SYSCTL_PROC(_net_inet_ip, IPCTL_FORWARDING, forwarding,
CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_LOCKED, &ipforwarding, 0,
sysctl_ipforwarding, "I", "Enable IP forwarding between interfaces");
static int ipsendredirects = 1; /* XXX */
SYSCTL_INT(_net_inet_ip, IPCTL_SENDREDIRECTS, redirect,
CTLFLAG_RW | CTLFLAG_LOCKED, &ipsendredirects, 0,
"Enable sending IP redirects");
int ip_defttl = IPDEFTTL;
SYSCTL_INT(_net_inet_ip, IPCTL_DEFTTL, ttl, CTLFLAG_RW | CTLFLAG_LOCKED,
&ip_defttl, 0, "Maximum TTL on IP packets");
static int ip_dosourceroute = 0;
SYSCTL_INT(_net_inet_ip, IPCTL_SOURCEROUTE, sourceroute,
CTLFLAG_RW | CTLFLAG_LOCKED, &ip_dosourceroute, 0,
"Enable forwarding source routed IP packets");
static int ip_acceptsourceroute = 0;
SYSCTL_INT(_net_inet_ip, IPCTL_ACCEPTSOURCEROUTE, accept_sourceroute,
CTLFLAG_RW | CTLFLAG_LOCKED, &ip_acceptsourceroute, 0,
"Enable accepting source routed IP packets");
static int ip_sendsourcequench = 0;
SYSCTL_INT(_net_inet_ip, OID_AUTO, sendsourcequench,
CTLFLAG_RW | CTLFLAG_LOCKED, &ip_sendsourcequench, 0,
"Enable the transmission of source quench packets");
SYSCTL_PROC(_net_inet_ip, OID_AUTO, maxfragpackets,
CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_LOCKED, &maxnipq, 0, sysctl_maxnipq,
"I", "Maximum number of IPv4 fragment reassembly queue entries");
SYSCTL_UINT(_net_inet_ip, OID_AUTO, fragpackets, CTLFLAG_RD | CTLFLAG_LOCKED,
&nipq, 0, "Current number of IPv4 fragment reassembly queue entries");
SYSCTL_PROC(_net_inet_ip, OID_AUTO, maxfragsperpacket,
CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_LOCKED, &maxfragsperpacket, 0,
sysctl_maxfragsperpacket, "I",
"Maximum number of IPv4 fragments allowed per packet");
static uint32_t ip_adj_clear_hwcksum = 0;
SYSCTL_UINT(_net_inet_ip, OID_AUTO, adj_clear_hwcksum,
CTLFLAG_RW | CTLFLAG_LOCKED, &ip_adj_clear_hwcksum, 0,
"Invalidate hwcksum info when adjusting length");
static uint32_t ip_adj_partial_sum = 1;
SYSCTL_UINT(_net_inet_ip, OID_AUTO, adj_partial_sum,
CTLFLAG_RW | CTLFLAG_LOCKED, &ip_adj_partial_sum, 0,
"Perform partial sum adjustment of trailing bytes at IP layer");
/*
* ip_checkinterface controls the receive side of the models for multihoming
* that are discussed in RFC 1122.
*
* ip_checkinterface values are:
* IP_CHECKINTERFACE_WEAK_ES:
* This corresponds to the Weak End-System model where incoming packets from
* any interface are accepted provided the destination address of the incoming packet
* is assigned to some interface.
*
* IP_CHECKINTERFACE_HYBRID_ES:
* The Hybrid End-System model use the Strong End-System for tunnel interfaces
* (ipsec and utun) and the weak End-System model for other interfaces families.
* This prevents a rogue middle box to probe for signs of TCP connections
* that use the tunnel interface.
*
* IP_CHECKINTERFACE_STRONG_ES:
* The Strong model model requires the packet arrived on an interface that
* is assigned the destination address of the packet.
*
* Since the routing table and transmit implementation do not implement the Strong ES model,
* setting this to a value different from IP_CHECKINTERFACE_WEAK_ES may lead to unexpected results.
*
* When forwarding is enabled, the system reverts to the Weak ES model as a router
* is expected by design to receive packets from several interfaces to the same address.
*
* XXX - ip_checkinterface currently must be set to IP_CHECKINTERFACE_WEAK_ES if you use ipnat
* to translate the destination address to another local interface.
*
* XXX - ip_checkinterface must be set to IP_CHECKINTERFACE_WEAK_ES if you add IP aliases
* to the loopback interface instead of the interface where the
* packets for those addresses are received.
*/
#define IP_CHECKINTERFACE_WEAK_ES 0
#define IP_CHECKINTERFACE_HYBRID_ES 1
#define IP_CHECKINTERFACE_STRONG_ES 2
static int ip_checkinterface = IP_CHECKINTERFACE_HYBRID_ES;
static int sysctl_ip_checkinterface SYSCTL_HANDLER_ARGS;
SYSCTL_PROC(_net_inet_ip, OID_AUTO, check_interface,
CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_LOCKED,
0, 0, sysctl_ip_checkinterface, "I", "Verify packet arrives on correct interface");
#if (DEBUG || DEVELOPMENT)
#define IP_CHECK_IF_DEBUG 1
#else
#define IP_CHECK_IF_DEBUG 0
#endif /* (DEBUG || DEVELOPMENT) */
static int ip_checkinterface_debug = IP_CHECK_IF_DEBUG;
SYSCTL_INT(_net_inet_ip, OID_AUTO, checkinterface_debug, CTLFLAG_RW | CTLFLAG_LOCKED,
&ip_checkinterface_debug, IP_CHECK_IF_DEBUG, "");
static int ip_chaining = 1;
SYSCTL_INT(_net_inet_ip, OID_AUTO, rx_chaining, CTLFLAG_RW | CTLFLAG_LOCKED,
&ip_chaining, 1, "Do receive side ip address based chaining");
static int ip_chainsz = 6;
SYSCTL_INT(_net_inet_ip, OID_AUTO, rx_chainsz, CTLFLAG_RW | CTLFLAG_LOCKED,
&ip_chainsz, 1, "IP receive side max chaining");
#if (DEBUG || DEVELOPMENT)
static int ip_input_measure = 0;
SYSCTL_PROC(_net_inet_ip, OID_AUTO, input_perf,
CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_LOCKED,
&ip_input_measure, 0, sysctl_reset_ip_input_stats, "I", "Do time measurement");
static uint64_t ip_input_measure_bins = 0;
SYSCTL_PROC(_net_inet_ip, OID_AUTO, input_perf_bins,
CTLTYPE_QUAD | CTLFLAG_RW | CTLFLAG_LOCKED, &ip_input_measure_bins, 0,
sysctl_ip_input_measure_bins, "I",
"bins for chaining performance data histogram");
static net_perf_t net_perf;
SYSCTL_PROC(_net_inet_ip, OID_AUTO, input_perf_data,
CTLTYPE_STRUCT | CTLFLAG_RD | CTLFLAG_LOCKED,
0, 0, sysctl_ip_input_getperf, "S,net_perf",
"IP input performance data (struct net_perf, net/net_perf.h)");
#endif /* (DEBUG || DEVELOPMENT) */
#if DIAGNOSTIC
static int ipprintfs = 0;
#endif
struct protosw *ip_protox[IPPROTO_MAX];
static LCK_GRP_DECLARE(in_ifaddr_rwlock_grp, "in_ifaddr_rwlock");
LCK_RW_DECLARE(in_ifaddr_rwlock, &in_ifaddr_rwlock_grp);
/* Protected by in_ifaddr_rwlock */
struct in_ifaddrhead in_ifaddrhead; /* first inet address */
struct in_ifaddrhashhead *in_ifaddrhashtbl; /* inet addr hash table */
#define INADDR_NHASH 61
static uint32_t inaddr_nhash; /* hash table size */
static uint32_t inaddr_hashp; /* next largest prime */
static int ip_getstat SYSCTL_HANDLER_ARGS;
struct ipstat ipstat;
SYSCTL_PROC(_net_inet_ip, IPCTL_STATS, stats,
CTLTYPE_STRUCT | CTLFLAG_RD | CTLFLAG_LOCKED,
0, 0, ip_getstat, "S,ipstat",
"IP statistics (struct ipstat, netinet/ip_var.h)");
#if IPCTL_DEFMTU
SYSCTL_INT(_net_inet_ip, IPCTL_DEFMTU, mtu, CTLFLAG_RW | CTLFLAG_LOCKED,
&ip_mtu, 0, "Default MTU");
#endif /* IPCTL_DEFMTU */
#if IPSTEALTH
static int ipstealth = 0;
SYSCTL_INT(_net_inet_ip, OID_AUTO, stealth, CTLFLAG_RW | CTLFLAG_LOCKED,
&ipstealth, 0, "");
#endif /* IPSTEALTH */
#if DUMMYNET
ip_dn_io_t *ip_dn_io_ptr;
#endif /* DUMMYNET */
SYSCTL_NODE(_net_inet_ip, OID_AUTO, linklocal,
CTLFLAG_RW | CTLFLAG_LOCKED, 0, "link local");
struct ip_linklocal_stat ip_linklocal_stat;
SYSCTL_STRUCT(_net_inet_ip_linklocal, OID_AUTO, stat,
CTLFLAG_RD | CTLFLAG_LOCKED, &ip_linklocal_stat, ip_linklocal_stat,
"Number of link local packets with TTL less than 255");
SYSCTL_NODE(_net_inet_ip_linklocal, OID_AUTO, in,
CTLFLAG_RW | CTLFLAG_LOCKED, 0, "link local input");
int ip_linklocal_in_allowbadttl = 1;
SYSCTL_INT(_net_inet_ip_linklocal_in, OID_AUTO, allowbadttl,
CTLFLAG_RW | CTLFLAG_LOCKED, &ip_linklocal_in_allowbadttl, 0,
"Allow incoming link local packets with TTL less than 255");
/*
* We need to save the IP options in case a protocol wants to respond
* to an incoming packet over the same route if the packet got here
* using IP source routing. This allows connection establishment and
* maintenance when the remote end is on a network that is not known
* to us.
*/
static int ip_nhops = 0;
static struct ip_srcrt {
struct in_addr dst; /* final destination */
char nop; /* one NOP to align */
char srcopt[IPOPT_OFFSET + 1]; /* OPTVAL, OLEN and OFFSET */
struct in_addr route[MAX_IPOPTLEN / sizeof(struct in_addr)];
} ip_srcrt;
static void in_ifaddrhashtbl_init(void);
static void save_rte(u_char *, struct in_addr);
static int ip_dooptions(struct mbuf *, int, struct sockaddr_in *);
static void ip_forward(struct mbuf *, int, struct sockaddr_in *);
static void frag_freef(struct ipqhead *, struct ipq *);
static struct mbuf *ip_reass(struct mbuf *);
static void ip_fwd_route_copyout(struct ifnet *, struct route *);
static void ip_fwd_route_copyin(struct ifnet *, struct route *);
static inline u_short ip_cksum(struct mbuf *, int);
/*
* On platforms which require strict alignment (currently for anything but
* i386 or x86_64 or arm64), check if the IP header pointer is 32-bit aligned; if not,
* copy the contents of the mbuf chain into a new chain, and free the original
* one. Create some head room in the first mbuf of the new chain, in case
* it's needed later on.
*/
#if defined(__i386__) || defined(__x86_64__) || defined(__arm64__)
#define IP_HDR_ALIGNMENT_FIXUP(_m, _ifp, _action) do { } while (0)
#else /* !__i386__ && !__x86_64__ && !__arm64__ */
#define IP_HDR_ALIGNMENT_FIXUP(_m, _ifp, _action) do { \
if (!IP_HDR_ALIGNED_P(mtod(_m, caddr_t))) { \
struct mbuf *_n; \
struct ifnet *__ifp = (_ifp); \
os_atomic_inc(&(__ifp)->if_alignerrs, relaxed); \
if (((_m)->m_flags & M_PKTHDR) && \
(_m)->m_pkthdr.pkt_hdr != NULL) \
(_m)->m_pkthdr.pkt_hdr = NULL; \
_n = m_defrag_offset(_m, max_linkhdr, M_NOWAIT); \
if (_n == NULL) { \
os_atomic_inc(&ipstat.ips_toosmall, relaxed); \
m_freem(_m); \
(_m) = NULL; \
_action; \
} else { \
VERIFY(_n != (_m)); \
(_m) = _n; \
} \
} \
} while (0)
#endif /* !__i386__ && !__x86_64__ && !__arm64__ */
typedef enum ip_check_if_result {
IP_CHECK_IF_NONE = 0,
IP_CHECK_IF_OURS = 1,
IP_CHECK_IF_DROP = 2,
IP_CHECK_IF_FORWARD = 3
} ip_check_if_result_t;
static ip_check_if_result_t ip_input_check_interface(struct mbuf **, struct ip *, struct ifnet *);
/*
* GRE input handler function, settable via ip_gre_register_input() for PPTP.
*/
static gre_input_func_t gre_input_func;
static void
ip_init_delayed(void)
{
struct ifreq ifr;
int error;
struct sockaddr_in *sin;
bzero(&ifr, sizeof(ifr));
strlcpy(ifr.ifr_name, "lo0", sizeof(ifr.ifr_name));
sin = SIN(&ifr.ifr_addr);
sin->sin_len = sizeof(struct sockaddr_in);
sin->sin_family = AF_INET;
sin->sin_addr.s_addr = htonl(INADDR_LOOPBACK);
error = in_control(NULL, SIOCSIFADDR, (caddr_t)&ifr, lo_ifp, kernproc);
if (error) {
printf("%s: failed to initialise lo0's address, error=%d\n",
__func__, error);
}
}
/*
* IP initialization: fill in IP protocol switch table.
* All protocols not implemented in kernel go to raw IP protocol handler.
*/
void
ip_init(struct protosw *pp, struct domain *dp)
{
static int ip_initialized = 0;
struct protosw *pr;
struct timeval tv;
int i;
domain_proto_mtx_lock_assert_held();
VERIFY((pp->pr_flags & (PR_INITIALIZED | PR_ATTACHED)) == PR_ATTACHED);
/*
* Some ioctls (e.g. SIOCAIFADDR) use ifaliasreq struct, which is
* interchangeable with in_aliasreq; they must have the same size.
*/
_CASSERT(sizeof(struct ifaliasreq) == sizeof(struct in_aliasreq));
if (ip_initialized) {
return;
}
ip_initialized = 1;
TAILQ_INIT(&in_ifaddrhead);
in_ifaddrhashtbl_init();
ip_moptions_init();
pr = pffindproto_locked(PF_INET, IPPROTO_RAW, SOCK_RAW);
if (pr == NULL) {
panic("%s: Unable to find [PF_INET,IPPROTO_RAW,SOCK_RAW]",
__func__);
/* NOTREACHED */
}
/* Initialize the entire ip_protox[] array to IPPROTO_RAW. */
for (i = 0; i < IPPROTO_MAX; i++) {
ip_protox[i] = pr;
}
/*
* Cycle through IP protocols and put them into the appropriate place
* in ip_protox[], skipping protocols IPPROTO_{IP,RAW}.
*/
VERIFY(dp == inetdomain && dp->dom_family == PF_INET);
TAILQ_FOREACH(pr, &dp->dom_protosw, pr_entry) {
VERIFY(pr->pr_domain == dp);
if (pr->pr_protocol != 0 && pr->pr_protocol != IPPROTO_RAW) {
/* Be careful to only index valid IP protocols. */
if (pr->pr_protocol < IPPROTO_MAX) {
ip_protox[pr->pr_protocol] = pr;
}
}
}
lck_mtx_lock(&ipqlock);
/* Initialize IP reassembly queue. */
for (i = 0; i < IPREASS_NHASH; i++) {
TAILQ_INIT(&ipq[i]);
}
maxnipq = nmbclusters / 32;
maxfragsperpacket = 128; /* enough for 64k in 512 byte fragments */
ipq_updateparams();
lck_mtx_unlock(&ipqlock);
getmicrotime(&tv);
ip_id = (u_short)(RandomULong() ^ tv.tv_usec);
PE_parse_boot_argn("ip_checkinterface", &i, sizeof(i));
switch (i) {
case IP_CHECKINTERFACE_WEAK_ES:
case IP_CHECKINTERFACE_HYBRID_ES:
case IP_CHECKINTERFACE_STRONG_ES:
ip_checkinterface = i;
break;
default:
break;
}
arp_init();
net_init_add(ip_init_delayed);
}
/*
* Initialize IPv4 source address hash table.
*/
static void
in_ifaddrhashtbl_init(void)
{
int i, k, p;
if (in_ifaddrhashtbl != NULL) {
return;
}
PE_parse_boot_argn("inaddr_nhash", &inaddr_nhash,
sizeof(inaddr_nhash));
if (inaddr_nhash == 0) {
inaddr_nhash = INADDR_NHASH;
}
in_ifaddrhashtbl = zalloc_permanent(
inaddr_nhash * sizeof(*in_ifaddrhashtbl),
ZALIGN_PTR);
/*
* Generate the next largest prime greater than inaddr_nhash.
*/
k = (inaddr_nhash % 2 == 0) ? inaddr_nhash + 1 : inaddr_nhash + 2;
for (;;) {
p = 1;
for (i = 3; i * i <= k; i += 2) {
if (k % i == 0) {
p = 0;
}
}
if (p == 1) {
break;
}
k += 2;
}
inaddr_hashp = k;
}
uint32_t
inaddr_hashval(uint32_t key)
{
/*
* The hash index is the computed prime times the key modulo
* the hash size, as documented in "Introduction to Algorithms"
* (Cormen, Leiserson, Rivest).
*/
if (inaddr_nhash > 1) {
return (key * inaddr_hashp) % inaddr_nhash;
} else {
return 0;
}
}
struct in_ifaddrhashhead *
inaddr_hashlookup(uint32_t key)
{
return &in_ifaddrhashtbl[inaddr_hashval(key)];
}
__private_extern__ void
ip_proto_dispatch_in(struct mbuf *m, int hlen, u_int8_t proto,
ipfilter_t inject_ipfref)
{
struct ipfilter *filter;
int seen = (inject_ipfref == NULL);
int changed_header = 0;
struct ip *ip;
void (*pr_input)(struct mbuf *, int len);
if (!TAILQ_EMPTY(&ipv4_filters)) {
ipf_ref();
TAILQ_FOREACH(filter, &ipv4_filters, ipf_link) {
if (seen == 0) {
if ((struct ipfilter *)inject_ipfref == filter) {
seen = 1;
}
} else if (filter->ipf_filter.ipf_input) {
errno_t result;
if (changed_header == 0) {
/*
* Perform IP header alignment fixup,
* if needed, before passing packet
* into filter(s).
*/
IP_HDR_ALIGNMENT_FIXUP(m,
m->m_pkthdr.rcvif, ipf_unref());
/* ipf_unref() already called */
if (m == NULL) {
return;
}
changed_header = 1;
ip = mtod(m, struct ip *);
ip->ip_len = htons(ip->ip_len + (uint16_t)hlen);
ip->ip_off = htons(ip->ip_off);
ip->ip_sum = 0;
ip->ip_sum = ip_cksum_hdr_in(m, hlen);
}
result = filter->ipf_filter.ipf_input(
filter->ipf_filter.cookie, (mbuf_t *)&m,
hlen, proto);
if (result == EJUSTRETURN) {
ipf_unref();
return;
}
if (result != 0) {
ipf_unref();
m_freem(m);
return;
}
}
}
ipf_unref();
}
/* Perform IP header alignment fixup (post-filters), if needed */
IP_HDR_ALIGNMENT_FIXUP(m, m->m_pkthdr.rcvif, return );
ip = mtod(m, struct ip *);
if (changed_header) {
ip->ip_len = ntohs(ip->ip_len) - (u_short)hlen;
ip->ip_off = ntohs(ip->ip_off);
}
/*
* If there isn't a specific lock for the protocol
* we're about to call, use the generic lock for AF_INET.
* otherwise let the protocol deal with its own locking
*/
if ((pr_input = ip_protox[ip->ip_p]->pr_input) == NULL) {
m_freem(m);
} else if (!(ip_protox[ip->ip_p]->pr_flags & PR_PROTOLOCK)) {
lck_mtx_lock(inet_domain_mutex);
pr_input(m, hlen);
lck_mtx_unlock(inet_domain_mutex);
} else {
pr_input(m, hlen);
}
}
struct pktchain_elm {
struct mbuf *pkte_head;
struct mbuf *pkte_tail;
struct in_addr pkte_saddr;
struct in_addr pkte_daddr;
uint16_t pkte_npkts;
uint16_t pkte_proto;
uint32_t pkte_nbytes;
};
typedef struct pktchain_elm pktchain_elm_t;
/* Store upto PKTTBL_SZ unique flows on the stack */
#define PKTTBL_SZ 7
static struct mbuf *
ip_chain_insert(struct mbuf *packet, pktchain_elm_t *tbl)
{
struct ip* ip;
int pkttbl_idx = 0;
ip = mtod(packet, struct ip*);
/* reusing the hash function from inaddr_hashval */
pkttbl_idx = inaddr_hashval(ntohl(ip->ip_src.s_addr)) % PKTTBL_SZ;
if (tbl[pkttbl_idx].pkte_head == NULL) {
tbl[pkttbl_idx].pkte_head = packet;
tbl[pkttbl_idx].pkte_saddr.s_addr = ip->ip_src.s_addr;
tbl[pkttbl_idx].pkte_daddr.s_addr = ip->ip_dst.s_addr;
tbl[pkttbl_idx].pkte_proto = ip->ip_p;
} else {
if ((ip->ip_dst.s_addr == tbl[pkttbl_idx].pkte_daddr.s_addr) &&
(ip->ip_src.s_addr == tbl[pkttbl_idx].pkte_saddr.s_addr) &&
(ip->ip_p == tbl[pkttbl_idx].pkte_proto)) {
} else {
return packet;
}
}
if (tbl[pkttbl_idx].pkte_tail != NULL) {
mbuf_setnextpkt(tbl[pkttbl_idx].pkte_tail, packet);
}
tbl[pkttbl_idx].pkte_tail = packet;
tbl[pkttbl_idx].pkte_npkts += 1;
tbl[pkttbl_idx].pkte_nbytes += packet->m_pkthdr.len;
return NULL;
}
/* args is a dummy variable here for backward compatibility */
static void
ip_input_second_pass_loop_tbl(pktchain_elm_t *tbl, struct ip_fw_in_args *args)
{
int i = 0;
for (i = 0; i < PKTTBL_SZ; i++) {
if (tbl[i].pkte_head != NULL) {
struct mbuf *m = tbl[i].pkte_head;
ip_input_second_pass(m, m->m_pkthdr.rcvif,
tbl[i].pkte_npkts, tbl[i].pkte_nbytes, args);
if (tbl[i].pkte_npkts > 2) {
ipstat.ips_rxc_chainsz_gt2++;
}
if (tbl[i].pkte_npkts > 4) {
ipstat.ips_rxc_chainsz_gt4++;
}
#if (DEBUG || DEVELOPMENT)
if (ip_input_measure) {
net_perf_histogram(&net_perf, tbl[i].pkte_npkts);
}
#endif /* (DEBUG || DEVELOPMENT) */
tbl[i].pkte_head = tbl[i].pkte_tail = NULL;
tbl[i].pkte_npkts = 0;
tbl[i].pkte_nbytes = 0;
/* no need to initialize address and protocol in tbl */
}
}
}
static void
ip_input_cpout_args(struct ip_fw_in_args *args, struct ip_fw_args *args1,
boolean_t *done_init)
{
if (*done_init == FALSE) {
bzero(args1, sizeof(struct ip_fw_args));
*done_init = TRUE;
}
args1->fwa_pf_rule = args->fwai_pf_rule;
}
static void
ip_input_cpin_args(struct ip_fw_args *args1, struct ip_fw_in_args *args)
{
args->fwai_pf_rule = args1->fwa_pf_rule;
}
typedef enum {
IPINPUT_DOCHAIN = 0,
IPINPUT_DONTCHAIN,
IPINPUT_FREED,
IPINPUT_DONE
} ipinput_chain_ret_t;
static void
ip_input_update_nstat(struct ifnet *ifp, struct in_addr src_ip,
u_int32_t packets, u_int32_t bytes)
{
if (nstat_collect) {
struct rtentry *rt = ifnet_cached_rtlookup_inet(ifp,
src_ip);
if (rt != NULL) {
nstat_route_rx(rt, packets, bytes, 0);
rtfree(rt);
}
}
}
static void
ip_input_dispatch_chain(struct mbuf *m)
{
struct mbuf *tmp_mbuf = m;
struct mbuf *nxt_mbuf = NULL;
struct ip *ip = NULL;
unsigned int hlen;
ip = mtod(tmp_mbuf, struct ip *);
hlen = IP_VHL_HL(ip->ip_vhl) << 2;
while (tmp_mbuf != NULL) {
nxt_mbuf = mbuf_nextpkt(tmp_mbuf);
mbuf_setnextpkt(tmp_mbuf, NULL);
ip_proto_dispatch_in(tmp_mbuf, hlen, ip->ip_p, 0);
tmp_mbuf = nxt_mbuf;
if (tmp_mbuf) {
ip = mtod(tmp_mbuf, struct ip *);
/* first mbuf of chain already has adjusted ip_len */
hlen = IP_VHL_HL(ip->ip_vhl) << 2;
ip->ip_len -= hlen;
}
}
}
static void
ip_input_setdst_chain(struct mbuf *m, uint16_t ifindex, struct in_ifaddr *ia)
{
struct mbuf *tmp_mbuf = m;
while (tmp_mbuf != NULL) {
ip_setdstifaddr_info(tmp_mbuf, ifindex, ia);
tmp_mbuf = mbuf_nextpkt(tmp_mbuf);
}
}
static void
ip_input_adjust(struct mbuf *m, struct ip *ip, struct ifnet *inifp)
{
boolean_t adjust = TRUE;
ASSERT(m_pktlen(m) > ip->ip_len);
/*
* Invalidate hardware checksum info if ip_adj_clear_hwcksum
* is set; useful to handle buggy drivers. Note that this
* should not be enabled by default, as we may get here due
* to link-layer padding.
*/
if (ip_adj_clear_hwcksum &&
(m->m_pkthdr.csum_flags & CSUM_DATA_VALID) &&
!(inifp->if_flags & IFF_LOOPBACK) &&
!(m->m_pkthdr.pkt_flags & PKTF_LOOP)) {
m->m_pkthdr.csum_flags &= ~CSUM_DATA_VALID;
m->m_pkthdr.csum_data = 0;
ipstat.ips_adj_hwcsum_clr++;
}
/*
* If partial checksum information is available, subtract
* out the partial sum of postpended extraneous bytes, and
* update the checksum metadata accordingly. By doing it
* here, the upper layer transport only needs to adjust any
* prepended extraneous bytes (else it will do both.)
*/
if (ip_adj_partial_sum &&
(m->m_pkthdr.csum_flags & (CSUM_DATA_VALID | CSUM_PARTIAL)) ==
(CSUM_DATA_VALID | CSUM_PARTIAL)) {
m->m_pkthdr.csum_rx_val = m_adj_sum16(m,
m->m_pkthdr.csum_rx_start, m->m_pkthdr.csum_rx_start,
(ip->ip_len - m->m_pkthdr.csum_rx_start),
m->m_pkthdr.csum_rx_val);
} else if ((m->m_pkthdr.csum_flags &
(CSUM_DATA_VALID | CSUM_PARTIAL)) ==
(CSUM_DATA_VALID | CSUM_PARTIAL)) {
/*
* If packet has partial checksum info and we decided not
* to subtract the partial sum of postpended extraneous
* bytes here (not the default case), leave that work to
* be handled by the other layers. For now, only TCP, UDP
* layers are capable of dealing with this. For all other
* protocols (including fragments), trim and ditch the
* partial sum as those layers might not implement partial
* checksumming (or adjustment) at all.
*/
if ((ip->ip_off & (IP_MF | IP_OFFMASK)) == 0 &&
(ip->ip_p == IPPROTO_TCP || ip->ip_p == IPPROTO_UDP)) {
adjust = FALSE;
} else {
m->m_pkthdr.csum_flags &= ~CSUM_DATA_VALID;
m->m_pkthdr.csum_data = 0;
ipstat.ips_adj_hwcsum_clr++;
}
}
if (adjust) {
ipstat.ips_adj++;
if (m->m_len == m->m_pkthdr.len) {
m->m_len = ip->ip_len;
m->m_pkthdr.len = ip->ip_len;
} else {
m_adj(m, ip->ip_len - m->m_pkthdr.len);
}
}
}
/*
* First pass does all essential packet validation and places on a per flow
* queue for doing operations that have same outcome for all packets of a flow.
*/
static ipinput_chain_ret_t
ip_input_first_pass(struct mbuf *m, struct ip_fw_in_args *args, struct mbuf **modm)
{
struct ip *ip;
struct ifnet *inifp;
unsigned int hlen;
int retval = IPINPUT_DOCHAIN;
int len = 0;
struct in_addr src_ip;
#if DUMMYNET
struct m_tag *copy;
struct m_tag *p;
boolean_t delete = FALSE;
struct ip_fw_args args1;
boolean_t init = FALSE;
#endif /* DUMMYNET */
ipfilter_t inject_filter_ref = NULL;
/* Check if the mbuf is still valid after interface filter processing */
MBUF_INPUT_CHECK(m, m->m_pkthdr.rcvif);
inifp = mbuf_pkthdr_rcvif(m);
VERIFY(inifp != NULL);
/* Perform IP header alignment fixup, if needed */
IP_HDR_ALIGNMENT_FIXUP(m, inifp, goto bad);
m->m_pkthdr.pkt_flags &= ~PKTF_FORWARDED;
#if DUMMYNET
/*
* Don't bother searching for tag(s) if there's none.
*/
if (SLIST_EMPTY(&m->m_pkthdr.tags)) {
goto ipfw_tags_done;
}
/* Grab info from mtags prepended to the chain */
p = m_tag_first(m);
while (p) {
if (p->m_tag_id == KERNEL_MODULE_TAG_ID) {
if (p->m_tag_type == KERNEL_TAG_TYPE_DUMMYNET) {
struct dn_pkt_tag *dn_tag;
dn_tag = (struct dn_pkt_tag *)(p->m_tag_data);
args->fwai_pf_rule = dn_tag->dn_pf_rule;
delete = TRUE;
}
if (delete) {
copy = p;
p = m_tag_next(m, p);
m_tag_delete(m, copy);
} else {
p = m_tag_next(m, p);
}
} else {
p = m_tag_next(m, p);
}
}
#if DIAGNOSTIC
if (m == NULL || !(m->m_flags & M_PKTHDR)) {
panic("ip_input no HDR");
}
#endif
if (args->fwai_pf_rule) {
/* dummynet already filtered us */
ip = mtod(m, struct ip *);
hlen = IP_VHL_HL(ip->ip_vhl) << 2;
inject_filter_ref = ipf_get_inject_filter(m);
if (args->fwai_pf_rule) {
goto check_with_pf;
}
}
ipfw_tags_done:
#endif /* DUMMYNET */
/*
* No need to process packet twice if we've already seen it.
*/
if (!SLIST_EMPTY(&m->m_pkthdr.tags)) {
inject_filter_ref = ipf_get_inject_filter(m);
}
if (inject_filter_ref != NULL) {
ip = mtod(m, struct ip *);
hlen = IP_VHL_HL(ip->ip_vhl) << 2;
DTRACE_IP6(receive, struct mbuf *, m, struct inpcb *, NULL,
struct ip *, ip, struct ifnet *, inifp,
struct ip *, ip, struct ip6_hdr *, NULL);
ip->ip_len = ntohs(ip->ip_len) - (u_short)hlen;
ip->ip_off = ntohs(ip->ip_off);
ip_proto_dispatch_in(m, hlen, ip->ip_p, inject_filter_ref);
return IPINPUT_DONE;
}
if (__improbable(m->m_pkthdr.pkt_flags & PKTF_WAKE_PKT)) {
if_ports_used_match_mbuf(inifp, PF_INET, m);
}
if (m->m_pkthdr.len < sizeof(struct ip)) {
OSAddAtomic(1, &ipstat.ips_total);
OSAddAtomic(1, &ipstat.ips_tooshort);
m_freem(m);
return IPINPUT_FREED;
}
if (m->m_len < sizeof(struct ip) &&
(m = m_pullup(m, sizeof(struct ip))) == NULL) {
OSAddAtomic(1, &ipstat.ips_total);
OSAddAtomic(1, &ipstat.ips_toosmall);
return IPINPUT_FREED;
}
ip = mtod(m, struct ip *);
*modm = m;
KERNEL_DEBUG(DBG_LAYER_BEG, ip->ip_dst.s_addr, ip->ip_src.s_addr,
ip->ip_p, ip->ip_off, ip->ip_len);
if (IP_VHL_V(ip->ip_vhl) != IPVERSION) {
OSAddAtomic(1, &ipstat.ips_total);
OSAddAtomic(1, &ipstat.ips_badvers);
KERNEL_DEBUG(DBG_LAYER_END, 0, 0, 0, 0, 0);
m_freem(m);
return IPINPUT_FREED;
}
hlen = IP_VHL_HL(ip->ip_vhl) << 2;
if (hlen < sizeof(struct ip)) {
OSAddAtomic(1, &ipstat.ips_total);
OSAddAtomic(1, &ipstat.ips_badhlen);
KERNEL_DEBUG(DBG_LAYER_END, 0, 0, 0, 0, 0);
m_freem(m);
return IPINPUT_FREED;
}
if (hlen > m->m_len) {
if ((m = m_pullup(m, hlen)) == NULL) {
OSAddAtomic(1, &ipstat.ips_total);
OSAddAtomic(1, &ipstat.ips_badhlen);
KERNEL_DEBUG(DBG_LAYER_END, 0, 0, 0, 0, 0);
return IPINPUT_FREED;
}
ip = mtod(m, struct ip *);
*modm = m;
}
if ((ip->ip_tos & IPTOS_ECN_MASK) == IPTOS_ECN_ECT1) {
m->m_pkthdr.pkt_ext_flags |= PKTF_EXT_L4S;
}
/* 127/8 must not appear on wire - RFC1122 */
if ((ntohl(ip->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET ||
(ntohl(ip->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET) {
/*
* Allow for the following exceptions:
*
* 1. If the packet was sent to loopback (i.e. rcvif
* would have been set earlier at output time.)
*
* 2. If the packet was sent out on loopback from a local
* source address which belongs to a non-loopback
* interface (i.e. rcvif may not necessarily be a
* loopback interface, hence the test for PKTF_LOOP.)
* Unlike IPv6, there is no interface scope ID, and
* therefore we don't care so much about PKTF_IFINFO.
*/
if (!(inifp->if_flags & IFF_LOOPBACK) &&
!(m->m_pkthdr.pkt_flags & PKTF_LOOP)) {
OSAddAtomic(1, &ipstat.ips_total);
OSAddAtomic(1, &ipstat.ips_badaddr);
KERNEL_DEBUG(DBG_LAYER_END, 0, 0, 0, 0, 0);
m_freem(m);
return IPINPUT_FREED;
}
}
/* IPv4 Link-Local Addresses as defined in RFC3927 */
if ((IN_LINKLOCAL(ntohl(ip->ip_dst.s_addr)) ||
IN_LINKLOCAL(ntohl(ip->ip_src.s_addr)))) {
ip_linklocal_stat.iplls_in_total++;
if (ip->ip_ttl != MAXTTL) {
OSAddAtomic(1, &ip_linklocal_stat.iplls_in_badttl);
/* Silently drop link local traffic with bad TTL */
if (!ip_linklocal_in_allowbadttl) {
OSAddAtomic(1, &ipstat.ips_total);
KERNEL_DEBUG(DBG_LAYER_END, 0, 0, 0, 0, 0);
m_freem(m);
return IPINPUT_FREED;
}
}
}
if (ip_cksum(m, hlen)) {
OSAddAtomic(1, &ipstat.ips_total);
KERNEL_DEBUG(DBG_LAYER_END, 0, 0, 0, 0, 0);
m_freem(m);
return IPINPUT_FREED;
}
DTRACE_IP6(receive, struct mbuf *, m, struct inpcb *, NULL,
struct ip *, ip, struct ifnet *, inifp,
struct ip *, ip, struct ip6_hdr *, NULL);
/*
* Convert fields to host representation.
*/
#if BYTE_ORDER != BIG_ENDIAN
NTOHS(ip->ip_len);
#endif
if (ip->ip_len < hlen) {
OSAddAtomic(1, &ipstat.ips_total);
OSAddAtomic(1, &ipstat.ips_badlen);
KERNEL_DEBUG(DBG_LAYER_END, 0, 0, 0, 0, 0);
m_freem(m);
return IPINPUT_FREED;
}
#if BYTE_ORDER != BIG_ENDIAN
NTOHS(ip->ip_off);
#endif
/*
* Check that the amount of data in the buffers
* is as at least much as the IP header would have us expect.
* Trim mbufs if longer than we expect.
* Drop packet if shorter than we expect.
*/
if (m->m_pkthdr.len < ip->ip_len) {
OSAddAtomic(1, &ipstat.ips_total);
OSAddAtomic(1, &ipstat.ips_tooshort);
KERNEL_DEBUG(DBG_LAYER_END, 0, 0, 0, 0, 0);
m_freem(m);
return IPINPUT_FREED;
}
if (m->m_pkthdr.len > ip->ip_len) {
ip_input_adjust(m, ip, inifp);
}
/* for netstat route statistics */
src_ip = ip->ip_src;
len = m->m_pkthdr.len;
#if DUMMYNET
check_with_pf:
#endif /* DUMMYNET */
#if PF
/* Invoke inbound packet filter */
if (PF_IS_ENABLED) {
int error;
ip_input_cpout_args(args, &args1, &init);
ip = mtod(m, struct ip *);
src_ip = ip->ip_src;
#if DUMMYNET
error = pf_af_hook(inifp, NULL, &m, AF_INET, TRUE, &args1);
#else
error = pf_af_hook(inifp, NULL, &m, AF_INET, TRUE, NULL);
#endif /* DUMMYNET */
if (error != 0 || m == NULL) {
if (m != NULL) {
panic("%s: unexpected packet %p",
__func__, m);
/* NOTREACHED */
}
/* Already freed by callee */
ip_input_update_nstat(inifp, src_ip, 1, len);
KERNEL_DEBUG(DBG_LAYER_END, 0, 0, 0, 0, 0);
OSAddAtomic(1, &ipstat.ips_total);
return IPINPUT_FREED;
}
ip = mtod(m, struct ip *);
hlen = IP_VHL_HL(ip->ip_vhl) << 2;
*modm = m;
ip_input_cpin_args(&args1, args);
}
#endif /* PF */
#if IPSEC
if (ipsec_bypass == 0 && ipsec_get_history_count(m)) {
retval = IPINPUT_DONTCHAIN; /* XXX scope for chaining here? */
goto pass;
}
#endif
#if IPSEC
pass:
#endif
/*
* Process options and, if not destined for us,
* ship it on. ip_dooptions returns 1 when an
* error was detected (causing an icmp message
* to be sent and the original packet to be freed).
*/
ip_nhops = 0; /* for source routed packets */
if (hlen > sizeof(struct ip) && ip_dooptions(m, 0, NULL)) {
src_ip = ip->ip_src;
ip_input_update_nstat(inifp, src_ip, 1, len);
KERNEL_DEBUG(DBG_LAYER_END, 0, 0, 0, 0, 0);
OSAddAtomic(1, &ipstat.ips_total);
return IPINPUT_FREED;
}
/*
* Don't chain fragmented packets
*/
if (ip->ip_off & ~(IP_DF | IP_RF)) {
return IPINPUT_DONTCHAIN;
}
/* Allow DHCP/BootP responses through */
if ((inifp->if_eflags & IFEF_AUTOCONFIGURING) &&
hlen == sizeof(struct ip) && ip->ip_p == IPPROTO_UDP) {
struct udpiphdr *ui;
if (m->m_len < sizeof(struct udpiphdr) &&
(m = m_pullup(m, sizeof(struct udpiphdr))) == NULL) {
OSAddAtomic(1, &udpstat.udps_hdrops);
KERNEL_DEBUG(DBG_LAYER_END, 0, 0, 0, 0, 0);
OSAddAtomic(1, &ipstat.ips_total);
return IPINPUT_FREED;
}
*modm = m;
ui = mtod(m, struct udpiphdr *);
if (ntohs(ui->ui_dport) == IPPORT_BOOTPC) {
ip_setdstifaddr_info(m, inifp->if_index, NULL);
return IPINPUT_DONTCHAIN;
}
}
/* Avoid chaining raw sockets as ipsec checks occur later for them */
if (ip_protox[ip->ip_p]->pr_flags & PR_LASTHDR) {
return IPINPUT_DONTCHAIN;
}
return retval;
#if !defined(__i386__) && !defined(__x86_64__) && !defined(__arm64__)
bad:
m_freem(m);
return IPINPUT_FREED;
#endif
}
/*
* Because the call to m_pullup() may freem the mbuf, the function frees the mbuf packet
* chain before it return IP_CHECK_IF_DROP
*/
static ip_check_if_result_t
ip_input_check_interface(struct mbuf **mp, struct ip *ip, struct ifnet *inifp)
{
struct mbuf *m = *mp;
struct in_ifaddr *ia = NULL;
struct in_ifaddr *best_ia = NULL;
struct ifnet *match_ifp = NULL;
ip_check_if_result_t result = IP_CHECK_IF_NONE;
/*
* Host broadcast and all network broadcast addresses are always a match
*/
if (ip->ip_dst.s_addr == (u_int32_t)INADDR_BROADCAST ||
ip->ip_dst.s_addr == INADDR_ANY) {
ip_input_setdst_chain(m, inifp->if_index, NULL);
return IP_CHECK_IF_OURS;
}
/*
* Check for a match in the hash bucket.
*/
lck_rw_lock_shared(&in_ifaddr_rwlock);
TAILQ_FOREACH(ia, INADDR_HASH(ip->ip_dst.s_addr), ia_hash) {
if (IA_SIN(ia)->sin_addr.s_addr == ip->ip_dst.s_addr) {
best_ia = ia;
match_ifp = best_ia->ia_ifp;
if (ia->ia_ifp == inifp || (inifp->if_flags & IFF_LOOPBACK) ||
(m->m_pkthdr.pkt_flags & PKTF_LOOP)) {
/*
* A locally originated packet or packet from the loopback
* interface is always an exact interface address match
*/
match_ifp = inifp;
break;
}
/*
* Continue the loop in case there's a exact match with another
* interface
*/
}
}
if (best_ia != NULL) {
if (match_ifp != inifp && ipforwarding == 0 &&
((ip_checkinterface == IP_CHECKINTERFACE_HYBRID_ES &&
(match_ifp->if_family == IFNET_FAMILY_IPSEC ||
match_ifp->if_family == IFNET_FAMILY_UTUN)) ||
ip_checkinterface == IP_CHECKINTERFACE_STRONG_ES)) {
/*
* Drop when interface address check is strict and forwarding
* is disabled
*/
result = IP_CHECK_IF_DROP;
} else {
result = IP_CHECK_IF_OURS;
ip_input_setdst_chain(m, 0, best_ia);
}
}
lck_rw_done(&in_ifaddr_rwlock);
if (result == IP_CHECK_IF_NONE && (inifp->if_flags & IFF_BROADCAST)) {
/*
* Check for broadcast addresses.
*
* Only accept broadcast packets that arrive via the matching
* interface. Reception of forwarded directed broadcasts would be
* handled via ip_forward() and ether_frameout() with the loopback
* into the stack for SIMPLEX interfaces handled by ether_frameout().
*/
struct ifaddr *ifa;
ifnet_lock_shared(inifp);
TAILQ_FOREACH(ifa, &inifp->if_addrhead, ifa_link) {
if (ifa->ifa_addr->sa_family != AF_INET) {
continue;
}
ia = ifatoia(ifa);
if (satosin(&ia->ia_broadaddr)->sin_addr.s_addr == ip->ip_dst.s_addr ||
ia->ia_netbroadcast.s_addr == ip->ip_dst.s_addr) {
ip_input_setdst_chain(m, 0, ia);
result = IP_CHECK_IF_OURS;
match_ifp = inifp;
break;
}
}
ifnet_lock_done(inifp);
}
/* Allow DHCP/BootP responses through */
if (result == IP_CHECK_IF_NONE && (inifp->if_eflags & IFEF_AUTOCONFIGURING) &&
ip->ip_p == IPPROTO_UDP && (IP_VHL_HL(ip->ip_vhl) << 2) == sizeof(struct ip)) {
struct udpiphdr *ui;
if (m->m_len < sizeof(struct udpiphdr)) {
if ((m = m_pullup(m, sizeof(struct udpiphdr))) == NULL) {
OSAddAtomic(1, &udpstat.udps_hdrops);
*mp = NULL;
return IP_CHECK_IF_DROP;
}
/*
* m_pullup can return a different mbuf
*/
*mp = m;
ip = mtod(m, struct ip *);
}
ui = mtod(m, struct udpiphdr *);
if (ntohs(ui->ui_dport) == IPPORT_BOOTPC) {
ip_input_setdst_chain(m, inifp->if_index, NULL);
result = IP_CHECK_IF_OURS;
match_ifp = inifp;
}
}
if (result == IP_CHECK_IF_NONE) {
if (ipforwarding == 0) {
result = IP_CHECK_IF_DROP;
} else {
result = IP_CHECK_IF_FORWARD;
ip_input_setdst_chain(m, inifp->if_index, NULL);
}
}
if (result == IP_CHECK_IF_OURS && match_ifp != inifp) {
ipstat.ips_rcv_if_weak_match++;
/* Logging is too noisy when forwarding is enabled */
if (ip_checkinterface_debug != 0 && ipforwarding == 0) {
char src_str[MAX_IPv4_STR_LEN];
char dst_str[MAX_IPv4_STR_LEN];
inet_ntop(AF_INET, &ip->ip_src, src_str, sizeof(src_str));
inet_ntop(AF_INET, &ip->ip_dst, dst_str, sizeof(dst_str));
os_log_info(OS_LOG_DEFAULT,
"%s: weak ES interface match to %s for packet from %s to %s proto %u received via %s",
__func__, best_ia->ia_ifp->if_xname, src_str, dst_str, ip->ip_p, inifp->if_xname);
}
} else if (result == IP_CHECK_IF_DROP) {
if (ip_checkinterface_debug > 0) {
char src_str[MAX_IPv4_STR_LEN];
char dst_str[MAX_IPv4_STR_LEN];
inet_ntop(AF_INET, &ip->ip_src, src_str, sizeof(src_str));
inet_ntop(AF_INET, &ip->ip_dst, dst_str, sizeof(dst_str));
os_log(OS_LOG_DEFAULT,
"%s: no interface match for packet from %s to %s proto %u received via %s",
__func__, src_str, dst_str, ip->ip_p, inifp->if_xname);
}
struct mbuf *tmp_mbuf = m;
while (tmp_mbuf != NULL) {
ipstat.ips_rcv_if_no_match++;
tmp_mbuf = tmp_mbuf->m_nextpkt;
}
m_freem_list(m);
*mp = NULL;
}
return result;
}
static void
ip_input_second_pass(struct mbuf *m, struct ifnet *inifp,
int npkts_in_chain, int bytes_in_chain, struct ip_fw_in_args *args)
{
struct mbuf *tmp_mbuf = NULL;
unsigned int hlen;
#pragma unused (args)
struct ip *ip = mtod(m, struct ip *);
hlen = IP_VHL_HL(ip->ip_vhl) << 2;
OSAddAtomic(npkts_in_chain, &ipstat.ips_total);
/*
* Naively assume we can attribute inbound data to the route we would
* use to send to this destination. Asymmetric routing breaks this
* assumption, but it still allows us to account for traffic from
* a remote node in the routing table.
* this has a very significant performance impact so we bypass
* if nstat_collect is disabled. We may also bypass if the
* protocol is tcp in the future because tcp will have a route that
* we can use to attribute the data to. That does mean we would not
* account for forwarded tcp traffic.
*/
ip_input_update_nstat(inifp, ip->ip_src, npkts_in_chain,
bytes_in_chain);
/*
* Check our list of addresses, to see if the packet is for us.
* If we don't have any addresses, assume any unicast packet
* we receive might be for us (and let the upper layers deal
* with it).
*/
tmp_mbuf = m;
if (TAILQ_EMPTY(&in_ifaddrhead)) {
while (tmp_mbuf != NULL) {
if (!(tmp_mbuf->m_flags & (M_MCAST | M_BCAST))) {
ip_setdstifaddr_info(tmp_mbuf, inifp->if_index,
NULL);
}
tmp_mbuf = mbuf_nextpkt(tmp_mbuf);
}
goto ours;
}
/*
* Enable a consistency check between the destination address
* and the arrival interface for a unicast packet (the RFC 1122
* strong ES model) if IP forwarding is disabled and the packet
* is not locally generated
*
* XXX - Checking also should be disabled if the destination
* address is ipnat'ed to a different interface.
*
* XXX - Checking is incompatible with IP aliases added
* to the loopback interface instead of the interface where
* the packets are received.
*/
if (!IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) {
ip_check_if_result_t ip_check_if_result = IP_CHECK_IF_NONE;
ip_check_if_result = ip_input_check_interface(&m, ip, inifp);
ASSERT(ip_check_if_result != IP_CHECK_IF_NONE);
if (ip_check_if_result == IP_CHECK_IF_OURS) {
goto ours;
} else if (ip_check_if_result == IP_CHECK_IF_DROP) {
return;
}
} else {
struct in_multi *inm;
/*
* See if we belong to the destination multicast group on the
* arrival interface.
*/
in_multihead_lock_shared();
IN_LOOKUP_MULTI(&ip->ip_dst, inifp, inm);
in_multihead_lock_done();
if (inm == NULL) {
OSAddAtomic(npkts_in_chain, &ipstat.ips_notmember);
m_freem_list(m);
KERNEL_DEBUG(DBG_LAYER_END, 0, 0, 0, 0, 0);
return;
}
ip_input_setdst_chain(m, inifp->if_index, NULL);
INM_REMREF(inm);
goto ours;
}
tmp_mbuf = m;
struct mbuf *nxt_mbuf = NULL;
while (tmp_mbuf != NULL) {
nxt_mbuf = mbuf_nextpkt(tmp_mbuf);
/*
* Not for us; forward if possible and desirable.
*/
mbuf_setnextpkt(tmp_mbuf, NULL);
if (ipforwarding == 0) {
OSAddAtomic(1, &ipstat.ips_cantforward);
m_freem(tmp_mbuf);
} else {
ip_forward(tmp_mbuf, 0, NULL);
}
tmp_mbuf = nxt_mbuf;
}
KERNEL_DEBUG(DBG_LAYER_END, 0, 0, 0, 0, 0);
return;
ours:
ip = mtod(m, struct ip *); /* in case it changed */
/*
* If offset is set, must reassemble.
*/
if (ip->ip_off & ~(IP_DF | IP_RF)) {
VERIFY(npkts_in_chain == 1);
m = ip_reass(m);
if (m == NULL) {
return;
}
ip = mtod(m, struct ip *);
/* Get the header length of the reassembled packet */
hlen = IP_VHL_HL(ip->ip_vhl) << 2;
}
/*
* Further protocols expect the packet length to be w/o the
* IP header.
*/
ip->ip_len -= hlen;
#if IPSEC
/*
* enforce IPsec policy checking if we are seeing last header.
* note that we do not visit this with protocols with pcb layer
* code - like udp/tcp/raw ip.
*/
if (ipsec_bypass == 0 && (ip_protox[ip->ip_p]->pr_flags & PR_LASTHDR)) {
VERIFY(npkts_in_chain == 1);
if (ipsec4_in_reject(m, NULL)) {
IPSEC_STAT_INCREMENT(ipsecstat.in_polvio);
goto bad;
}
}
#endif /* IPSEC */
/*
* Switch out to protocol's input routine.
*/
OSAddAtomic(npkts_in_chain, &ipstat.ips_delivered);
ip_input_dispatch_chain(m);
KERNEL_DEBUG(DBG_LAYER_END, 0, 0, 0, 0, 0);
return;
bad:
KERNEL_DEBUG(DBG_LAYER_END, 0, 0, 0, 0, 0);
m_freem(m);
}
void
ip_input_process_list(struct mbuf *packet_list)
{
pktchain_elm_t pktchain_tbl[PKTTBL_SZ];
struct mbuf *packet = NULL;
struct mbuf *modm = NULL; /* modified mbuf */
int retval = 0;
#if (DEBUG || DEVELOPMENT)
struct timeval start_tv;
#endif /* (DEBUG || DEVELOPMENT) */
int num_pkts = 0;
int chain = 0;
struct ip_fw_in_args args;
if (ip_chaining == 0) {
struct mbuf *m = packet_list;
#if (DEBUG || DEVELOPMENT)
if (ip_input_measure) {
net_perf_start_time(&net_perf, &start_tv);
}
#endif /* (DEBUG || DEVELOPMENT) */
while (m) {
packet_list = mbuf_nextpkt(m);
mbuf_setnextpkt(m, NULL);
ip_input(m);
m = packet_list;
num_pkts++;
}
#if (DEBUG || DEVELOPMENT)
if (ip_input_measure) {
net_perf_measure_time(&net_perf, &start_tv, num_pkts);
}
#endif /* (DEBUG || DEVELOPMENT) */
return;
}
#if (DEBUG || DEVELOPMENT)
if (ip_input_measure) {
net_perf_start_time(&net_perf, &start_tv);
}
#endif /* (DEBUG || DEVELOPMENT) */
bzero(&pktchain_tbl, sizeof(pktchain_tbl));
restart_list_process:
chain = 0;
for (packet = packet_list; packet; packet = packet_list) {
m_add_crumb(packet, PKT_CRUMB_IP_INPUT);
packet_list = mbuf_nextpkt(packet);
mbuf_setnextpkt(packet, NULL);
num_pkts++;
modm = NULL;
bzero(&args, sizeof(args));
retval = ip_input_first_pass(packet, &args, &modm);
if (retval == IPINPUT_DOCHAIN) {
if (modm) {
packet = modm;
}
packet = ip_chain_insert(packet, &pktchain_tbl[0]);
if (packet == NULL) {
ipstat.ips_rxc_chained++;
chain++;
if (chain > ip_chainsz) {
break;
}
} else {
ipstat.ips_rxc_collisions++;
break;
}
} else if (retval == IPINPUT_DONTCHAIN) {
/* in order to preserve order, exit from chaining */
if (modm) {
packet = modm;
}
ipstat.ips_rxc_notchain++;
break;
} else {
/* packet was freed or delivered, do nothing. */
}
}
/* do second pass here for pktchain_tbl */
if (chain) {
ip_input_second_pass_loop_tbl(&pktchain_tbl[0], &args);
}
if (packet) {
/*
* equivalent update in chaining case if performed in
* ip_input_second_pass_loop_tbl().
*/
#if (DEBUG || DEVELOPMENT)
if (ip_input_measure) {
net_perf_histogram(&net_perf, 1);
}
#endif /* (DEBUG || DEVELOPMENT) */
ip_input_second_pass(packet, packet->m_pkthdr.rcvif,
1, packet->m_pkthdr.len, &args);
}
if (packet_list) {
goto restart_list_process;
}
#if (DEBUG || DEVELOPMENT)
if (ip_input_measure) {
net_perf_measure_time(&net_perf, &start_tv, num_pkts);
}
#endif /* (DEBUG || DEVELOPMENT) */
}
/*
* Ip input routine. Checksum and byte swap header. If fragmented
* try to reassemble. Process options. Pass to next level.
*/
void
ip_input(struct mbuf *m)
{
struct ip *ip;
unsigned int hlen;
u_short sum = 0;
#if DUMMYNET
struct ip_fw_args args;
struct m_tag *tag;
#endif
ipfilter_t inject_filter_ref = NULL;
struct ifnet *inifp;
/* Check if the mbuf is still valid after interface filter processing */
MBUF_INPUT_CHECK(m, m->m_pkthdr.rcvif);
inifp = m->m_pkthdr.rcvif;
VERIFY(inifp != NULL);
m_add_crumb(m, PKT_CRUMB_IP_INPUT);
ipstat.ips_rxc_notlist++;
/* Perform IP header alignment fixup, if needed */
IP_HDR_ALIGNMENT_FIXUP(m, inifp, goto bad);
m->m_pkthdr.pkt_flags &= ~PKTF_FORWARDED;
#if DUMMYNET
bzero(&args, sizeof(struct ip_fw_args));
/*
* Don't bother searching for tag(s) if there's none.
*/
if (SLIST_EMPTY(&m->m_pkthdr.tags)) {
goto ipfw_tags_done;
}
/* Grab info from mtags prepended to the chain */
if ((tag = m_tag_locate(m, KERNEL_MODULE_TAG_ID,
KERNEL_TAG_TYPE_DUMMYNET)) != NULL) {
struct dn_pkt_tag *dn_tag;
dn_tag = (struct dn_pkt_tag *)(tag->m_tag_data);
args.fwa_pf_rule = dn_tag->dn_pf_rule;
m_tag_delete(m, tag);
}
#if DIAGNOSTIC
if (m == NULL || !(m->m_flags & M_PKTHDR)) {
panic("ip_input no HDR");
}
#endif
if (args.fwa_pf_rule) {
/* dummynet already filtered us */
ip = mtod(m, struct ip *);
hlen = IP_VHL_HL(ip->ip_vhl) << 2;
inject_filter_ref = ipf_get_inject_filter(m);
if (args.fwa_pf_rule) {
goto check_with_pf;
}
}
ipfw_tags_done:
#endif /* DUMMYNET */
/*
* No need to process packet twice if we've already seen it.
*/
if (!SLIST_EMPTY(&m->m_pkthdr.tags)) {
inject_filter_ref = ipf_get_inject_filter(m);
}
if (inject_filter_ref != NULL) {
ip = mtod(m, struct ip *);
hlen = IP_VHL_HL(ip->ip_vhl) << 2;
DTRACE_IP6(receive, struct mbuf *, m, struct inpcb *, NULL,
struct ip *, ip, struct ifnet *, inifp,
struct ip *, ip, struct ip6_hdr *, NULL);
ip->ip_len = ntohs(ip->ip_len) - (u_short)hlen;
ip->ip_off = ntohs(ip->ip_off);
ip_proto_dispatch_in(m, hlen, ip->ip_p, inject_filter_ref);
return;
}
if (__improbable(m->m_pkthdr.pkt_flags & PKTF_WAKE_PKT)) {
if_ports_used_match_mbuf(inifp, PF_INET, m);
}
OSAddAtomic(1, &ipstat.ips_total);
if (m->m_pkthdr.len < sizeof(struct ip)) {
goto tooshort;
}
if (m->m_len < sizeof(struct ip) &&
(m = m_pullup(m, sizeof(struct ip))) == NULL) {
OSAddAtomic(1, &ipstat.ips_toosmall);
return;
}
ip = mtod(m, struct ip *);
KERNEL_DEBUG(DBG_LAYER_BEG, ip->ip_dst.s_addr, ip->ip_src.s_addr,
ip->ip_p, ip->ip_off, ip->ip_len);
if (IP_VHL_V(ip->ip_vhl) != IPVERSION) {
OSAddAtomic(1, &ipstat.ips_badvers);
goto bad;
}
hlen = IP_VHL_HL(ip->ip_vhl) << 2;
if (hlen < sizeof(struct ip)) { /* minimum header length */
OSAddAtomic(1, &ipstat.ips_badhlen);
goto bad;
}
if (hlen > m->m_len) {
if ((m = m_pullup(m, hlen)) == NULL) {
OSAddAtomic(1, &ipstat.ips_badhlen);
return;
}
ip = mtod(m, struct ip *);
}
/* 127/8 must not appear on wire - RFC1122 */
if ((ntohl(ip->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET ||
(ntohl(ip->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET) {
/*
* Allow for the following exceptions:
*
* 1. If the packet was sent to loopback (i.e. rcvif
* would have been set earlier at output time.)
*
* 2. If the packet was sent out on loopback from a local
* source address which belongs to a non-loopback
* interface (i.e. rcvif may not necessarily be a
* loopback interface, hence the test for PKTF_LOOP.)
* Unlike IPv6, there is no interface scope ID, and
* therefore we don't care so much about PKTF_IFINFO.
*/
if (!(inifp->if_flags & IFF_LOOPBACK) &&
!(m->m_pkthdr.pkt_flags & PKTF_LOOP)) {
OSAddAtomic(1, &ipstat.ips_badaddr);
goto bad;
}
}
/* IPv4 Link-Local Addresses as defined in RFC3927 */
if ((IN_LINKLOCAL(ntohl(ip->ip_dst.s_addr)) ||
IN_LINKLOCAL(ntohl(ip->ip_src.s_addr)))) {
ip_linklocal_stat.iplls_in_total++;
if (ip->ip_ttl != MAXTTL) {
OSAddAtomic(1, &ip_linklocal_stat.iplls_in_badttl);
/* Silently drop link local traffic with bad TTL */
if (!ip_linklocal_in_allowbadttl) {
goto bad;
}
}
}
sum = ip_cksum(m, hlen);
if (sum) {
goto bad;
}
DTRACE_IP6(receive, struct mbuf *, m, struct inpcb *, NULL,
struct ip *, ip, struct ifnet *, inifp,
struct ip *, ip, struct ip6_hdr *, NULL);
/*
* Naively assume we can attribute inbound data to the route we would
* use to send to this destination. Asymmetric routing breaks this
* assumption, but it still allows us to account for traffic from
* a remote node in the routing table.
* this has a very significant performance impact so we bypass
* if nstat_collect is disabled. We may also bypass if the
* protocol is tcp in the future because tcp will have a route that
* we can use to attribute the data to. That does mean we would not
* account for forwarded tcp traffic.
*/
if (nstat_collect) {
struct rtentry *rt =
ifnet_cached_rtlookup_inet(inifp, ip->ip_src);
if (rt != NULL) {
nstat_route_rx(rt, 1, m->m_pkthdr.len, 0);
rtfree(rt);
}
}
/*
* Convert fields to host representation.
*/
#if BYTE_ORDER != BIG_ENDIAN
NTOHS(ip->ip_len);
#endif
if (ip->ip_len < hlen) {
OSAddAtomic(1, &ipstat.ips_badlen);
goto bad;
}
#if BYTE_ORDER != BIG_ENDIAN
NTOHS(ip->ip_off);
#endif
/*
* Check that the amount of data in the buffers
* is as at least much as the IP header would have us expect.
* Trim mbufs if longer than we expect.
* Drop packet if shorter than we expect.
*/
if (m->m_pkthdr.len < ip->ip_len) {
tooshort:
OSAddAtomic(1, &ipstat.ips_tooshort);
goto bad;
}
if (m->m_pkthdr.len > ip->ip_len) {
ip_input_adjust(m, ip, inifp);
}
#if DUMMYNET
check_with_pf:
#endif
#if PF
/* Invoke inbound packet filter */
if (PF_IS_ENABLED) {
int error;
#if DUMMYNET
error = pf_af_hook(inifp, NULL, &m, AF_INET, TRUE, &args);
#else
error = pf_af_hook(inifp, NULL, &m, AF_INET, TRUE, NULL);
#endif /* DUMMYNET */
if (error != 0 || m == NULL) {
if (m != NULL) {
panic("%s: unexpected packet %p",
__func__, m);
/* NOTREACHED */
}
/* Already freed by callee */
return;
}
ip = mtod(m, struct ip *);
hlen = IP_VHL_HL(ip->ip_vhl) << 2;
}
#endif /* PF */
#if IPSEC
if (ipsec_bypass == 0 && ipsec_get_history_count(m)) {
goto pass;
}
#endif
pass:
/*
* Process options and, if not destined for us,
* ship it on. ip_dooptions returns 1 when an
* error was detected (causing an icmp message
* to be sent and the original packet to be freed).
*/
ip_nhops = 0; /* for source routed packets */
if (hlen > sizeof(struct ip) && ip_dooptions(m, 0, NULL)) {
return;
}
/*
* Check our list of addresses, to see if the packet is for us.
* If we don't have any addresses, assume any unicast packet
* we receive might be for us (and let the upper layers deal
* with it).
*/
if (TAILQ_EMPTY(&in_ifaddrhead) && !(m->m_flags & (M_MCAST | M_BCAST))) {
ip_setdstifaddr_info(m, inifp->if_index, NULL);
goto ours;
}
/*
* Enable a consistency check between the destination address
* and the arrival interface for a unicast packet (the RFC 1122
* strong ES model) if IP forwarding is disabled and the packet
* is not locally generated and the packet is not subject to
* 'ipfw fwd'.
*
* XXX - Checking also should be disabled if the destination
* address is ipnat'ed to a different interface.
*
* XXX - Checking is incompatible with IP aliases added
* to the loopback interface instead of the interface where
* the packets are received.
*/
if (!IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) {
ip_check_if_result_t check_if_result = IP_CHECK_IF_NONE;
check_if_result = ip_input_check_interface(&m, ip, inifp);
ASSERT(check_if_result != IP_CHECK_IF_NONE);
if (check_if_result == IP_CHECK_IF_OURS) {
goto ours;
} else if (check_if_result == IP_CHECK_IF_DROP) {
return;
}
} else {
struct in_multi *inm;
/*
* See if we belong to the destination multicast group on the
* arrival interface.
*/
in_multihead_lock_shared();
IN_LOOKUP_MULTI(&ip->ip_dst, inifp, inm);
in_multihead_lock_done();
if (inm == NULL) {
OSAddAtomic(1, &ipstat.ips_notmember);
m_freem(m);
return;
}
ip_setdstifaddr_info(m, inifp->if_index, NULL);
INM_REMREF(inm);
goto ours;
}
/*
* Not for us; forward if possible and desirable.
*/
if (ipforwarding == 0) {
OSAddAtomic(1, &ipstat.ips_cantforward);
m_freem(m);
} else {
ip_forward(m, 0, NULL);
}
return;
ours:
/*
* If offset or IP_MF are set, must reassemble.
*/
if (ip->ip_off & ~(IP_DF | IP_RF)) {
m = ip_reass(m);
if (m == NULL) {
return;
}
ip = mtod(m, struct ip *);
/* Get the header length of the reassembled packet */
hlen = IP_VHL_HL(ip->ip_vhl) << 2;
}
/*
* Further protocols expect the packet length to be w/o the
* IP header.
*/
ip->ip_len -= hlen;
#if IPSEC
/*
* enforce IPsec policy checking if we are seeing last header.
* note that we do not visit this with protocols with pcb layer
* code - like udp/tcp/raw ip.
*/
if (ipsec_bypass == 0 && (ip_protox[ip->ip_p]->pr_flags & PR_LASTHDR)) {
if (ipsec4_in_reject(m, NULL)) {
IPSEC_STAT_INCREMENT(ipsecstat.in_polvio);
goto bad;
}
}
#endif /* IPSEC */
/*
* Switch out to protocol's input routine.
*/
OSAddAtomic(1, &ipstat.ips_delivered);
ip_proto_dispatch_in(m, hlen, ip->ip_p, 0);
return;
bad:
KERNEL_DEBUG(DBG_LAYER_END, 0, 0, 0, 0, 0);
m_freem(m);
}
static void
ipq_updateparams(void)
{
LCK_MTX_ASSERT(&ipqlock, LCK_MTX_ASSERT_OWNED);
/*
* -1 for unlimited allocation.
*/
if (maxnipq < 0) {
ipq_limit = 0;
}
/*
* Positive number for specific bound.
*/
if (maxnipq > 0) {
ipq_limit = maxnipq;
}
/*
* Zero specifies no further fragment queue allocation -- set the
* bound very low, but rely on implementation elsewhere to actually
* prevent allocation and reclaim current queues.
*/
if (maxnipq == 0) {
ipq_limit = 1;
}
/*
* Arm the purge timer if not already and if there's work to do
*/
frag_sched_timeout();
}
static int
sysctl_maxnipq SYSCTL_HANDLER_ARGS
{
#pragma unused(arg1, arg2)
int error, i;
lck_mtx_lock(&ipqlock);
i = maxnipq;
error = sysctl_handle_int(oidp, &i, 0, req);
if (error || req->newptr == USER_ADDR_NULL) {
goto done;
}
/* impose bounds */
if (i < -1 || i > (nmbclusters / 4)) {
error = EINVAL;
goto done;
}
maxnipq = i;
ipq_updateparams();
done:
lck_mtx_unlock(&ipqlock);
return error;
}
static int
sysctl_maxfragsperpacket SYSCTL_HANDLER_ARGS
{
#pragma unused(arg1, arg2)
int error, i;
lck_mtx_lock(&ipqlock);
i = maxfragsperpacket;
error = sysctl_handle_int(oidp, &i, 0, req);
if (error || req->newptr == USER_ADDR_NULL) {
goto done;
}
maxfragsperpacket = i;
ipq_updateparams(); /* see if we need to arm timer */
done:
lck_mtx_unlock(&ipqlock);
return error;
}
/*
* Take incoming datagram fragment and try to reassemble it into
* whole datagram. If a chain for reassembly of this datagram already
* exists, then it is given as fp; otherwise have to make a chain.
*
* The IP header is *NOT* adjusted out of iplen (but in host byte order).
*/
static struct mbuf *
ip_reass(struct mbuf *m)
{
struct ip *ip;
struct mbuf *p, *q, *nq, *t;
struct ipq *fp = NULL;
struct ipqhead *head;
int i, hlen, next;
u_int8_t ecn, ecn0;
uint32_t csum, csum_flags;
uint16_t hash;
struct fq_head dfq;
MBUFQ_INIT(&dfq); /* for deferred frees */
/* If maxnipq or maxfragsperpacket is 0, never accept fragments. */
if (maxnipq == 0 || maxfragsperpacket == 0) {
ipstat.ips_fragments++;
ipstat.ips_fragdropped++;
m_freem(m);
if (nipq > 0) {
lck_mtx_lock(&ipqlock);
frag_sched_timeout(); /* purge stale fragments */
lck_mtx_unlock(&ipqlock);
}
return NULL;
}
ip = mtod(m, struct ip *);
hlen = IP_VHL_HL(ip->ip_vhl) << 2;
lck_mtx_lock(&ipqlock);
hash = IPREASS_HASH(ip->ip_src.s_addr, ip->ip_id);
head = &ipq[hash];
/*
* Look for queue of fragments
* of this datagram.
*/
TAILQ_FOREACH(fp, head, ipq_list) {
if (ip->ip_id == fp->ipq_id &&
ip->ip_src.s_addr == fp->ipq_src.s_addr &&
ip->ip_dst.s_addr == fp->ipq_dst.s_addr &&
ip->ip_p == fp->ipq_p) {
goto found;
}
}
fp = NULL;
/*
* Attempt to trim the number of allocated fragment queues if it
* exceeds the administrative limit.
*/
if ((nipq > (unsigned)maxnipq) && (maxnipq > 0)) {
/*
* drop something from the tail of the current queue
* before proceeding further
*/
struct ipq *fq = TAILQ_LAST(head, ipqhead);
if (fq == NULL) { /* gak */
for (i = 0; i < IPREASS_NHASH; i++) {
struct ipq *r = TAILQ_LAST(&ipq[i], ipqhead);
if (r) {
ipstat.ips_fragtimeout += r->ipq_nfrags;
frag_freef(&ipq[i], r);
break;
}
}
} else {
ipstat.ips_fragtimeout += fq->ipq_nfrags;
frag_freef(head, fq);
}
}
found:
/*
* Leverage partial checksum offload for IP fragments. Narrow down
* the scope to cover only UDP without IP options, as that is the
* most common case.
*
* Perform 1's complement adjustment of octets that got included/
* excluded in the hardware-calculated checksum value. Ignore cases
* where the value includes the entire IPv4 header span, as the sum
* for those octets would already be 0 by the time we get here; IP
* has already performed its header checksum validation. Also take
* care of any trailing bytes and subtract out their partial sum.
*/
if (ip->ip_p == IPPROTO_UDP && hlen == sizeof(struct ip) &&
(m->m_pkthdr.csum_flags &
(CSUM_DATA_VALID | CSUM_PARTIAL | CSUM_PSEUDO_HDR)) ==
(CSUM_DATA_VALID | CSUM_PARTIAL)) {
uint32_t start = m->m_pkthdr.csum_rx_start;
int32_t trailer = (m_pktlen(m) - ip->ip_len);
uint32_t swbytes = (uint32_t)trailer;
csum = m->m_pkthdr.csum_rx_val;
ASSERT(trailer >= 0);
if ((start != 0 && start != hlen) || trailer != 0) {
uint32_t datalen = ip->ip_len - hlen;
#if BYTE_ORDER != BIG_ENDIAN
if (start < hlen) {
HTONS(ip->ip_len);
HTONS(ip->ip_off);
}
#endif /* BYTE_ORDER != BIG_ENDIAN */
/* callee folds in sum */
csum = m_adj_sum16(m, start, hlen, datalen, csum);
if (hlen > start) {
swbytes += (hlen - start);
} else {
swbytes += (start - hlen);
}
#if BYTE_ORDER != BIG_ENDIAN
if (start < hlen) {
NTOHS(ip->ip_off);
NTOHS(ip->ip_len);
}
#endif /* BYTE_ORDER != BIG_ENDIAN */
}
csum_flags = m->m_pkthdr.csum_flags;
if (swbytes != 0) {
udp_in_cksum_stats(swbytes);
}
if (trailer != 0) {
m_adj(m, -trailer);
}
} else {
csum = 0;
csum_flags = 0;
}
/* Invalidate checksum */
m->m_pkthdr.csum_flags &= ~CSUM_DATA_VALID;
ipstat.ips_fragments++;
/*
* Adjust ip_len to not reflect header,
* convert offset of this to bytes.
*/
ip->ip_len -= hlen;
if (ip->ip_off & IP_MF) {
/*
* Make sure that fragments have a data length
* that's a non-zero multiple of 8 bytes.
*/
if (ip->ip_len == 0 || (ip->ip_len & 0x7) != 0) {
OSAddAtomic(1, &ipstat.ips_toosmall);
/*
* Reassembly queue may have been found if previous
* fragments were valid; given that this one is bad,
* we need to drop it. Make sure to set fp to NULL
* if not already, since we don't want to decrement
* ipq_nfrags as it doesn't include this packet.
*/
fp = NULL;
goto dropfrag;
}
m->m_flags |= M_FRAG;
} else {
/* Clear the flag in case packet comes from loopback */
m->m_flags &= ~M_FRAG;
}
ip->ip_off = (u_short)(ip->ip_off << 3);
m->m_pkthdr.pkt_hdr = ip;
/* Previous ip_reass() started here. */
/*
* Presence of header sizes in mbufs
* would confuse code below.
*/
m->m_data += hlen;
m->m_len -= hlen;
/*
* If first fragment to arrive, create a reassembly queue.
*/
if (fp == NULL) {
fp = ipq_alloc();
if (fp == NULL) {
goto dropfrag;
}
TAILQ_INSERT_HEAD(head, fp, ipq_list);
nipq++;
fp->ipq_nfrags = 1;
fp->ipq_ttl = IPFRAGTTL;
fp->ipq_p = ip->ip_p;
fp->ipq_id = ip->ip_id;
fp->ipq_src = ip->ip_src;
fp->ipq_dst = ip->ip_dst;
fp->ipq_frags = m;
m->m_nextpkt = NULL;
/*
* If the first fragment has valid checksum offload
* info, the rest of fragments are eligible as well.
*/
if (csum_flags != 0) {
fp->ipq_csum = csum;
fp->ipq_csum_flags = csum_flags;
}
m = NULL; /* nothing to return */
goto done;
} else {
fp->ipq_nfrags++;
}
#define GETIP(m) ((struct ip *)((m)->m_pkthdr.pkt_hdr))
/*
* Handle ECN by comparing this segment with the first one;
* if CE is set, do not lose CE.
* drop if CE and not-ECT are mixed for the same packet.
*/
ecn = ip->ip_tos & IPTOS_ECN_MASK;
ecn0 = GETIP(fp->ipq_frags)->ip_tos & IPTOS_ECN_MASK;
if (ecn == IPTOS_ECN_CE) {
if (ecn0 == IPTOS_ECN_NOTECT) {
goto dropfrag;
}
if (ecn0 != IPTOS_ECN_CE) {
GETIP(fp->ipq_frags)->ip_tos |= IPTOS_ECN_CE;
}
}
if (ecn == IPTOS_ECN_NOTECT && ecn0 != IPTOS_ECN_NOTECT) {
goto dropfrag;
}
/*
* Find a segment which begins after this one does.
*/
for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) {
if (GETIP(q)->ip_off > ip->ip_off) {
break;
}
}
/*
* If there is a preceding segment, it may provide some of
* our data already. If so, drop the data from the incoming
* segment. If it provides all of our data, drop us, otherwise
* stick new segment in the proper place.
*
* If some of the data is dropped from the preceding
* segment, then it's checksum is invalidated.
*/
if (p) {
i = GETIP(p)->ip_off + GETIP(p)->ip_len - ip->ip_off;
if (i > 0) {
if (i >= ip->ip_len) {
goto dropfrag;
}
m_adj(m, i);
fp->ipq_csum_flags = 0;
ip->ip_off += i;
ip->ip_len -= i;
}
m->m_nextpkt = p->m_nextpkt;
p->m_nextpkt = m;
} else {
m->m_nextpkt = fp->ipq_frags;
fp->ipq_frags = m;
}
/*
* While we overlap succeeding segments trim them or,
* if they are completely covered, dequeue them.
*/
for (; q != NULL && ip->ip_off + ip->ip_len > GETIP(q)->ip_off;
q = nq) {
i = (ip->ip_off + ip->ip_len) - GETIP(q)->ip_off;
if (i < GETIP(q)->ip_len) {
GETIP(q)->ip_len -= i;
GETIP(q)->ip_off += i;
m_adj(q, i);
fp->ipq_csum_flags = 0;
break;
}
nq = q->m_nextpkt;
m->m_nextpkt = nq;
ipstat.ips_fragdropped++;
fp->ipq_nfrags--;
/* defer freeing until after lock is dropped */
MBUFQ_ENQUEUE(&dfq, q);
}
/*
* If this fragment contains similar checksum offload info
* as that of the existing ones, accumulate checksum. Otherwise,
* invalidate checksum offload info for the entire datagram.
*/
if (csum_flags != 0 && csum_flags == fp->ipq_csum_flags) {
fp->ipq_csum += csum;
} else if (fp->ipq_csum_flags != 0) {
fp->ipq_csum_flags = 0;
}
/*
* Check for complete reassembly and perform frag per packet
* limiting.
*
* Frag limiting is performed here so that the nth frag has
* a chance to complete the packet before we drop the packet.
* As a result, n+1 frags are actually allowed per packet, but
* only n will ever be stored. (n = maxfragsperpacket.)
*
*/
next = 0;
for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) {
if (GETIP(q)->ip_off != next) {
if (fp->ipq_nfrags > maxfragsperpacket) {
ipstat.ips_fragdropped += fp->ipq_nfrags;
frag_freef(head, fp);
}
m = NULL; /* nothing to return */
goto done;
}
next += GETIP(q)->ip_len;
}
/* Make sure the last packet didn't have the IP_MF flag */
if (p->m_flags & M_FRAG) {
if (fp->ipq_nfrags > maxfragsperpacket) {
ipstat.ips_fragdropped += fp->ipq_nfrags;
frag_freef(head, fp);
}
m = NULL; /* nothing to return */
goto done;
}
/*
* Reassembly is complete. Make sure the packet is a sane size.
*/
q = fp->ipq_frags;
ip = GETIP(q);
if (next + (IP_VHL_HL(ip->ip_vhl) << 2) > IP_MAXPACKET) {
ipstat.ips_toolong++;
ipstat.ips_fragdropped += fp->ipq_nfrags;
frag_freef(head, fp);
m = NULL; /* nothing to return */
goto done;
}
/*
* Concatenate fragments.
*/
m = q;
t = m->m_next;
m->m_next = NULL;
m_cat(m, t);
nq = q->m_nextpkt;
q->m_nextpkt = NULL;
for (q = nq; q != NULL; q = nq) {
nq = q->m_nextpkt;
q->m_nextpkt = NULL;
m_cat(m, q);
}
/*
* Store partial hardware checksum info from the fragment queue;
* the receive start offset is set to 20 bytes (see code at the
* top of this routine.)
*/
if (fp->ipq_csum_flags != 0) {
csum = fp->ipq_csum;
ADDCARRY(csum);
m->m_pkthdr.csum_rx_val = (uint16_t)csum;
m->m_pkthdr.csum_rx_start = sizeof(struct ip);
m->m_pkthdr.csum_flags = fp->ipq_csum_flags;
} else if ((m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) ||
(m->m_pkthdr.pkt_flags & PKTF_LOOP)) {
/* loopback checksums are always OK */
m->m_pkthdr.csum_data = 0xffff;
m->m_pkthdr.csum_flags =
CSUM_DATA_VALID | CSUM_PSEUDO_HDR |
CSUM_IP_CHECKED | CSUM_IP_VALID;
}
/*
* Create header for new ip packet by modifying header of first
* packet; dequeue and discard fragment reassembly header.
* Make header visible.
*/
ip->ip_len = (u_short)((IP_VHL_HL(ip->ip_vhl) << 2) + next);
ip->ip_src = fp->ipq_src;
ip->ip_dst = fp->ipq_dst;
fp->ipq_frags = NULL; /* return to caller as 'm' */
frag_freef(head, fp);
fp = NULL;
m->m_len += (IP_VHL_HL(ip->ip_vhl) << 2);
m->m_data -= (IP_VHL_HL(ip->ip_vhl) << 2);
/* some debugging cruft by sklower, below, will go away soon */
if (m->m_flags & M_PKTHDR) { /* XXX this should be done elsewhere */
m_fixhdr(m);
}
ipstat.ips_reassembled++;
/* arm the purge timer if not already and if there's work to do */
frag_sched_timeout();
lck_mtx_unlock(&ipqlock);
/* perform deferred free (if needed) now that lock is dropped */
if (!MBUFQ_EMPTY(&dfq)) {
MBUFQ_DRAIN(&dfq);
}
VERIFY(MBUFQ_EMPTY(&dfq));
return m;
done:
VERIFY(m == NULL);
/* arm the purge timer if not already and if there's work to do */
frag_sched_timeout();
lck_mtx_unlock(&ipqlock);
/* perform deferred free (if needed) */
if (!MBUFQ_EMPTY(&dfq)) {
MBUFQ_DRAIN(&dfq);
}
VERIFY(MBUFQ_EMPTY(&dfq));
return NULL;
dropfrag:
ipstat.ips_fragdropped++;
if (fp != NULL) {
fp->ipq_nfrags--;
}
/* arm the purge timer if not already and if there's work to do */
frag_sched_timeout();
lck_mtx_unlock(&ipqlock);
m_freem(m);
/* perform deferred free (if needed) */
if (!MBUFQ_EMPTY(&dfq)) {
MBUFQ_DRAIN(&dfq);
}
VERIFY(MBUFQ_EMPTY(&dfq));
return NULL;
#undef GETIP
}
/*
* Free a fragment reassembly header and all
* associated datagrams.
*/
static void
frag_freef(struct ipqhead *fhp, struct ipq *fp)
{
LCK_MTX_ASSERT(&ipqlock, LCK_MTX_ASSERT_OWNED);
fp->ipq_nfrags = 0;
if (fp->ipq_frags != NULL) {
m_freem_list(fp->ipq_frags);
fp->ipq_frags = NULL;
}
TAILQ_REMOVE(fhp, fp, ipq_list);
nipq--;
ipq_free(fp);
}
/*
* IP reassembly timer processing
*/
static void
frag_timeout(void *arg)
{
#pragma unused(arg)
struct ipq *fp;
int i;
/*
* Update coarse-grained networking timestamp (in sec.); the idea
* is to piggy-back on the timeout callout to update the counter
* returnable via net_uptime().
*/
net_update_uptime();
lck_mtx_lock(&ipqlock);
for (i = 0; i < IPREASS_NHASH; i++) {
for (fp = TAILQ_FIRST(&ipq[i]); fp;) {
struct ipq *fpp;
fpp = fp;
fp = TAILQ_NEXT(fp, ipq_list);
if (--fpp->ipq_ttl == 0) {
ipstat.ips_fragtimeout += fpp->ipq_nfrags;
frag_freef(&ipq[i], fpp);
}
}
}
/*
* If we are over the maximum number of fragments
* (due to the limit being lowered), drain off
* enough to get down to the new limit.
*/
if (maxnipq >= 0 && nipq > (unsigned)maxnipq) {
for (i = 0; i < IPREASS_NHASH; i++) {
while (nipq > (unsigned)maxnipq &&
!TAILQ_EMPTY(&ipq[i])) {
ipstat.ips_fragdropped +=
TAILQ_FIRST(&ipq[i])->ipq_nfrags;
frag_freef(&ipq[i], TAILQ_FIRST(&ipq[i]));
}
}
}
/* re-arm the purge timer if there's work to do */
frag_timeout_run = 0;
frag_sched_timeout();
lck_mtx_unlock(&ipqlock);
}
static void
frag_sched_timeout(void)
{
LCK_MTX_ASSERT(&ipqlock, LCK_MTX_ASSERT_OWNED);
if (!frag_timeout_run && nipq > 0) {
frag_timeout_run = 1;
timeout(frag_timeout, NULL, hz);
}
}
/*
* Drain off all datagram fragments.
*/
static void
frag_drain(void)
{
int i;
lck_mtx_lock(&ipqlock);
for (i = 0; i < IPREASS_NHASH; i++) {
while (!TAILQ_EMPTY(&ipq[i])) {
ipstat.ips_fragdropped +=
TAILQ_FIRST(&ipq[i])->ipq_nfrags;
frag_freef(&ipq[i], TAILQ_FIRST(&ipq[i]));
}
}
lck_mtx_unlock(&ipqlock);
}
static struct ipq *
ipq_alloc(void)
{
struct ipq *fp;
/*
* See comments in ipq_updateparams(). Keep the count separate
* from nipq since the latter represents the elements already
* in the reassembly queues.
*/
if (ipq_limit > 0 && ipq_count > ipq_limit) {
return NULL;
}
fp = kalloc_type(struct ipq, Z_NOWAIT | Z_ZERO);
if (fp != NULL) {
os_atomic_inc(&ipq_count, relaxed);
}
return fp;
}
static void
ipq_free(struct ipq *fp)
{
kfree_type(struct ipq, fp);
os_atomic_dec(&ipq_count, relaxed);
}
/*
* Drain callback
*/
void
ip_drain(void)
{
frag_drain(); /* fragments */
in_rtqdrain(); /* protocol cloned routes */
in_arpdrain(NULL); /* cloned routes: ARP */
}
/*
* Do option processing on a datagram,
* possibly discarding it if bad options are encountered,
* or forwarding it if source-routed.
* The pass argument is used when operating in the IPSTEALTH
* mode to tell what options to process:
* [LS]SRR (pass 0) or the others (pass 1).
* The reason for as many as two passes is that when doing IPSTEALTH,
* non-routing options should be processed only if the packet is for us.
* Returns 1 if packet has been forwarded/freed,
* 0 if the packet should be processed further.
*/
static int
ip_dooptions(struct mbuf *m, int pass, struct sockaddr_in *next_hop)
{
#pragma unused(pass)
struct ip *ip = mtod(m, struct ip *);
u_char *cp;
struct ip_timestamp *ipt;
struct in_ifaddr *ia;
int opt, optlen, cnt, off, type = ICMP_PARAMPROB, forward = 0;
uint8_t code = 0;
struct in_addr *sin, dst;
u_int32_t ntime;
struct sockaddr_in ipaddr = {
.sin_len = sizeof(ipaddr),
.sin_family = AF_INET,
.sin_port = 0,
.sin_addr = { .s_addr = 0 },
.sin_zero = { 0, }
};
/* Expect 32-bit aligned data pointer on strict-align platforms */
MBUF_STRICT_DATA_ALIGNMENT_CHECK_32(m);
dst = ip->ip_dst;
cp = (u_char *)(ip + 1);
cnt = (IP_VHL_HL(ip->ip_vhl) << 2) - sizeof(struct ip);
for (; cnt > 0; cnt -= optlen, cp += optlen) {
opt = cp[IPOPT_OPTVAL];
if (opt == IPOPT_EOL) {
break;
}
if (opt == IPOPT_NOP) {
optlen = 1;
} else {
if (cnt < IPOPT_OLEN + sizeof(*cp)) {
code = (uint8_t)(&cp[IPOPT_OLEN] - (u_char *)ip);
goto bad;
}
optlen = cp[IPOPT_OLEN];
if (optlen < IPOPT_OLEN + sizeof(*cp) ||
optlen > cnt) {
code = (uint8_t)(&cp[IPOPT_OLEN] - (u_char *)ip);
goto bad;
}
}
switch (opt) {
default:
break;
/*
* Source routing with record.
* Find interface with current destination address.
* If none on this machine then drop if strictly routed,
* or do nothing if loosely routed.
* Record interface address and bring up next address
* component. If strictly routed make sure next
* address is on directly accessible net.
*/
case IPOPT_LSRR:
case IPOPT_SSRR:
if (optlen < IPOPT_OFFSET + sizeof(*cp)) {
code = (uint8_t)(&cp[IPOPT_OLEN] - (u_char *)ip);
goto bad;
}
if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) {
code = (uint8_t)(&cp[IPOPT_OFFSET] - (u_char *)ip);
goto bad;
}
ipaddr.sin_addr = ip->ip_dst;
ia = (struct in_ifaddr *)ifa_ifwithaddr(SA(&ipaddr));
if (ia == NULL) {
if (opt == IPOPT_SSRR) {
type = ICMP_UNREACH;
code = ICMP_UNREACH_SRCFAIL;
goto bad;
}
if (!ip_dosourceroute) {
goto nosourcerouting;
}
/*
* Loose routing, and not at next destination
* yet; nothing to do except forward.
*/
break;
} else {
ifa_remref(&ia->ia_ifa);
ia = NULL;
}
off--; /* 0 origin */
if (off > optlen - (int)sizeof(struct in_addr)) {
/*
* End of source route. Should be for us.
*/
if (!ip_acceptsourceroute) {
goto nosourcerouting;
}
save_rte(cp, ip->ip_src);
break;
}
if (!ip_dosourceroute) {
if (ipforwarding) {
char buf[MAX_IPv4_STR_LEN];
char buf2[MAX_IPv4_STR_LEN];
/*
* Acting as a router, so generate ICMP
*/
nosourcerouting:
log(LOG_WARNING,
"attempted source route from %s "
"to %s\n",
inet_ntop(AF_INET, &ip->ip_src,
buf, sizeof(buf)),
inet_ntop(AF_INET, &ip->ip_dst,
buf2, sizeof(buf2)));
type = ICMP_UNREACH;
code = ICMP_UNREACH_SRCFAIL;
goto bad;
} else {
/*
* Not acting as a router,
* so silently drop.
*/
OSAddAtomic(1, &ipstat.ips_cantforward);
m_freem(m);
return 1;
}
}
/*
* locate outgoing interface
*/
(void) memcpy(&ipaddr.sin_addr, cp + off,
sizeof(ipaddr.sin_addr));
if (opt == IPOPT_SSRR) {
#define INA struct in_ifaddr *
if ((ia = (INA)ifa_ifwithdstaddr(
SA(&ipaddr))) == NULL) {
ia = (INA)ifa_ifwithnet(SA(&ipaddr));
}
} else {
ia = ip_rtaddr(ipaddr.sin_addr);
}
if (ia == NULL) {
type = ICMP_UNREACH;
code = ICMP_UNREACH_SRCFAIL;
goto bad;
}
ip->ip_dst = ipaddr.sin_addr;
IFA_LOCK(&ia->ia_ifa);
(void) memcpy(cp + off, &(IA_SIN(ia)->sin_addr),
sizeof(struct in_addr));
IFA_UNLOCK(&ia->ia_ifa);
ifa_remref(&ia->ia_ifa);
ia = NULL;
cp[IPOPT_OFFSET] += sizeof(struct in_addr);
/*
* Let ip_intr's mcast routing check handle mcast pkts
*/
forward = !IN_MULTICAST(ntohl(ip->ip_dst.s_addr));
break;
case IPOPT_RR:
if (optlen < IPOPT_OFFSET + sizeof(*cp)) {
code = (uint8_t)(&cp[IPOPT_OFFSET] - (u_char *)ip);
goto bad;
}
if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) {
code = (uint8_t)(&cp[IPOPT_OFFSET] - (u_char *)ip);
goto bad;
}
/*
* If no space remains, ignore.
*/
off--; /* 0 origin */
if (off > optlen - (int)sizeof(struct in_addr)) {
break;
}
(void) memcpy(&ipaddr.sin_addr, &ip->ip_dst,
sizeof(ipaddr.sin_addr));
/*
* locate outgoing interface; if we're the destination,
* use the incoming interface (should be same).
*/
if ((ia = (INA)ifa_ifwithaddr(SA(&ipaddr))) == NULL) {
if ((ia = ip_rtaddr(ipaddr.sin_addr)) == NULL) {
type = ICMP_UNREACH;
code = ICMP_UNREACH_HOST;
goto bad;
}
}
IFA_LOCK(&ia->ia_ifa);
(void) memcpy(cp + off, &(IA_SIN(ia)->sin_addr),
sizeof(struct in_addr));
IFA_UNLOCK(&ia->ia_ifa);
ifa_remref(&ia->ia_ifa);
ia = NULL;
cp[IPOPT_OFFSET] += sizeof(struct in_addr);
break;
case IPOPT_TS:
code = (uint8_t)(cp - (u_char *)ip);
ipt = (struct ip_timestamp *)(void *)cp;
if (ipt->ipt_len < 4 || ipt->ipt_len > 40) {
code = (uint8_t)((u_char *)&ipt->ipt_len -
(u_char *)ip);
goto bad;
}
if (ipt->ipt_ptr < 5) {
code = (uint8_t)((u_char *)&ipt->ipt_ptr -
(u_char *)ip);
goto bad;
}
if (ipt->ipt_ptr >
ipt->ipt_len - (int)sizeof(int32_t)) {
if (++ipt->ipt_oflw == 0) {
code = (uint8_t)((u_char *)&ipt->ipt_ptr -
(u_char *)ip);
goto bad;
}
break;
}
sin = (struct in_addr *)(void *)(cp + ipt->ipt_ptr - 1);
switch (ipt->ipt_flg) {
case IPOPT_TS_TSONLY:
break;
case IPOPT_TS_TSANDADDR:
if (ipt->ipt_ptr - 1 + sizeof(n_time) +
sizeof(struct in_addr) > ipt->ipt_len) {
code = (uint8_t)((u_char *)&ipt->ipt_ptr -
(u_char *)ip);
goto bad;
}
ipaddr.sin_addr = dst;
ia = (INA)ifaof_ifpforaddr(SA(&ipaddr),
m->m_pkthdr.rcvif);
if (ia == NULL) {
continue;
}
IFA_LOCK(&ia->ia_ifa);
(void) memcpy(sin, &IA_SIN(ia)->sin_addr,
sizeof(struct in_addr));
IFA_UNLOCK(&ia->ia_ifa);
ipt->ipt_ptr += sizeof(struct in_addr);
ifa_remref(&ia->ia_ifa);
ia = NULL;
break;
case IPOPT_TS_PRESPEC:
if (ipt->ipt_ptr - 1 + sizeof(n_time) +
sizeof(struct in_addr) > ipt->ipt_len) {
code = (uint8_t)((u_char *)&ipt->ipt_ptr -
(u_char *)ip);
goto bad;
}
(void) memcpy(&ipaddr.sin_addr, sin,
sizeof(struct in_addr));
if ((ia = (struct in_ifaddr *)ifa_ifwithaddr(
SA(&ipaddr))) == NULL) {
continue;
}
ifa_remref(&ia->ia_ifa);
ia = NULL;
ipt->ipt_ptr += sizeof(struct in_addr);
break;
default:
/* XXX can't take &ipt->ipt_flg */
code = (uint8_t)((u_char *)&ipt->ipt_ptr -
(u_char *)ip + 1);
goto bad;
}
ntime = iptime();
(void) memcpy(cp + ipt->ipt_ptr - 1, &ntime,
sizeof(n_time));
ipt->ipt_ptr += sizeof(n_time);
}
}
if (forward && ipforwarding) {
ip_forward(m, 1, next_hop);
return 1;
}
return 0;
bad:
icmp_error(m, type, code, 0, 0);
OSAddAtomic(1, &ipstat.ips_badoptions);
return 1;
}
/*
* Check for the presence of the IP Router Alert option [RFC2113]
* in the header of an IPv4 datagram.
*
* This call is not intended for use from the forwarding path; it is here
* so that protocol domains may check for the presence of the option.
* Given how FreeBSD's IPv4 stack is currently structured, the Router Alert
* option does not have much relevance to the implementation, though this
* may change in future.
* Router alert options SHOULD be passed if running in IPSTEALTH mode and
* we are not the endpoint.
* Length checks on individual options should already have been peformed
* by ip_dooptions() therefore they are folded under DIAGNOSTIC here.
*
* Return zero if not present or options are invalid, non-zero if present.
*/
int
ip_checkrouteralert(struct mbuf *m)
{
struct ip *ip = mtod(m, struct ip *);
u_char *cp;
int opt, optlen, cnt, found_ra;
found_ra = 0;
cp = (u_char *)(ip + 1);
cnt = (IP_VHL_HL(ip->ip_vhl) << 2) - sizeof(struct ip);
for (; cnt > 0; cnt -= optlen, cp += optlen) {
opt = cp[IPOPT_OPTVAL];
if (opt == IPOPT_EOL) {
break;
}
if (opt == IPOPT_NOP) {
optlen = 1;
} else {
#ifdef DIAGNOSTIC
if (cnt < IPOPT_OLEN + sizeof(*cp)) {
break;
}
#endif
optlen = cp[IPOPT_OLEN];
#ifdef DIAGNOSTIC
if (optlen < IPOPT_OLEN + sizeof(*cp) || optlen > cnt) {
break;
}
#endif
}
switch (opt) {
case IPOPT_RA:
#ifdef DIAGNOSTIC
if (optlen != IPOPT_OFFSET + sizeof(uint16_t) ||
(*((uint16_t *)(void *)&cp[IPOPT_OFFSET]) != 0)) {
break;
} else
#endif
found_ra = 1;
break;
default:
break;
}
}
return found_ra;
}
/*
* Given address of next destination (final or next hop),
* return internet address info of interface to be used to get there.
*/
struct in_ifaddr *
ip_rtaddr(struct in_addr dst)
{
struct sockaddr_in *sin;
struct ifaddr *rt_ifa;
struct route ro;
bzero(&ro, sizeof(ro));
sin = SIN(&ro.ro_dst);
sin->sin_family = AF_INET;
sin->sin_len = sizeof(*sin);
sin->sin_addr = dst;
rtalloc_ign(&ro, RTF_PRCLONING);
if (ro.ro_rt == NULL) {
ROUTE_RELEASE(&ro);
return NULL;
}
RT_LOCK(ro.ro_rt);
if ((rt_ifa = ro.ro_rt->rt_ifa) != NULL) {
ifa_addref(rt_ifa);
}
RT_UNLOCK(ro.ro_rt);
ROUTE_RELEASE(&ro);
return (struct in_ifaddr *)rt_ifa;
}
/*
* Save incoming source route for use in replies,
* to be picked up later by ip_srcroute if the receiver is interested.
*/
void
save_rte(u_char *option, struct in_addr dst)
{
unsigned olen;
olen = option[IPOPT_OLEN];
#if DIAGNOSTIC
if (ipprintfs) {
printf("save_rte: olen %d\n", olen);
}
#endif
if (olen > sizeof(ip_srcrt) - (1 + sizeof(dst))) {
return;
}
bcopy(option, ip_srcrt.srcopt, olen);
ip_nhops = (olen - IPOPT_OFFSET - 1) / sizeof(struct in_addr);
ip_srcrt.dst = dst;
}
/*
* Retrieve incoming source route for use in replies,
* in the same form used by setsockopt.
* The first hop is placed before the options, will be removed later.
*/
struct mbuf *
ip_srcroute(void)
{
struct in_addr *p, *q;
struct mbuf *m;
if (ip_nhops == 0) {
return NULL;
}
m = m_get(M_DONTWAIT, MT_HEADER);
if (m == NULL) {
return NULL;
}
#define OPTSIZ (sizeof (ip_srcrt.nop) + sizeof (ip_srcrt.srcopt))
/* length is (nhops+1)*sizeof(addr) + sizeof(nop + srcrt header) */
m->m_len = ip_nhops * sizeof(struct in_addr) +
sizeof(struct in_addr) + OPTSIZ;
#if DIAGNOSTIC
if (ipprintfs) {
printf("ip_srcroute: nhops %d mlen %d", ip_nhops, m->m_len);
}
#endif
/*
* First save first hop for return route
*/
p = &ip_srcrt.route[ip_nhops - 1];
*(mtod(m, struct in_addr *)) = *p--;
#if DIAGNOSTIC
if (ipprintfs) {
printf(" hops %lx",
(u_int32_t)ntohl(mtod(m, struct in_addr *)->s_addr));
}
#endif
/*
* Copy option fields and padding (nop) to mbuf.
*/
ip_srcrt.nop = IPOPT_NOP;
ip_srcrt.srcopt[IPOPT_OFFSET] = IPOPT_MINOFF;
(void) __nochk_memcpy(mtod(m, caddr_t) + sizeof(struct in_addr),
&ip_srcrt.nop, OPTSIZ);
q = (struct in_addr *)(void *)(mtod(m, caddr_t) +
sizeof(struct in_addr) + OPTSIZ);
#undef OPTSIZ
/*
* Record return path as an IP source route,
* reversing the path (pointers are now aligned).
*/
while (p >= ip_srcrt.route) {
#if DIAGNOSTIC
if (ipprintfs) {
printf(" %lx", (u_int32_t)ntohl(q->s_addr));
}
#endif
*q++ = *p--;
}
/*
* Last hop goes to final destination.
*/
*q = ip_srcrt.dst;
#if DIAGNOSTIC
if (ipprintfs) {
printf(" %lx\n", (u_int32_t)ntohl(q->s_addr));
}
#endif
return m;
}
/*
* Strip out IP options, at higher level protocol in the kernel.
*/
void
ip_stripoptions(struct mbuf *m)
{
int i;
struct ip *ip = mtod(m, struct ip *);
caddr_t opts;
int olen;
/* Expect 32-bit aligned data pointer on strict-align platforms */
MBUF_STRICT_DATA_ALIGNMENT_CHECK_32(m);
/* use bcopy() since it supports overlapping range */
olen = (IP_VHL_HL(ip->ip_vhl) << 2) - sizeof(struct ip);
opts = (caddr_t)(ip + 1);
i = m->m_len - (sizeof(struct ip) + olen);
bcopy(opts + olen, opts, (unsigned)i);
m->m_len -= olen;
if (m->m_flags & M_PKTHDR) {
m->m_pkthdr.len -= olen;
}
ip->ip_vhl = IP_MAKE_VHL(IPVERSION, sizeof(struct ip) >> 2);
/*
* We expect ip_{off,len} to be in host order by now, and
* that the original IP header length has been subtracted
* out from ip_len. Temporarily adjust ip_len for checksum
* recalculation, and restore it afterwards.
*/
ip->ip_len += sizeof(struct ip);
/* recompute checksum now that IP header is smaller */
#if BYTE_ORDER != BIG_ENDIAN
HTONS(ip->ip_len);
HTONS(ip->ip_off);
#endif /* BYTE_ORDER != BIG_ENDIAN */
ip->ip_sum = in_cksum_hdr(ip);
#if BYTE_ORDER != BIG_ENDIAN
NTOHS(ip->ip_off);
NTOHS(ip->ip_len);
#endif /* BYTE_ORDER != BIG_ENDIAN */
ip->ip_len -= sizeof(struct ip);
/*
* Given that we've just stripped IP options from the header,
* we need to adjust the start offset accordingly if this
* packet had gone thru partial checksum offload.
*/
if ((m->m_pkthdr.csum_flags & (CSUM_DATA_VALID | CSUM_PARTIAL)) ==
(CSUM_DATA_VALID | CSUM_PARTIAL)) {
if (m->m_pkthdr.csum_rx_start >= (sizeof(struct ip) + olen)) {
/* most common case */
m->m_pkthdr.csum_rx_start -= olen;
} else {
/* compute checksum in software instead */
m->m_pkthdr.csum_flags &= ~CSUM_DATA_VALID;
m->m_pkthdr.csum_data = 0;
ipstat.ips_adj_hwcsum_clr++;
}
}
}
u_char inetctlerrmap[PRC_NCMDS] = {
0, 0, 0, 0,
0, EMSGSIZE, EHOSTDOWN, EHOSTUNREACH,
ENETUNREACH, EHOSTUNREACH, ECONNREFUSED, ECONNREFUSED,
EMSGSIZE, EHOSTUNREACH, 0, 0,
0, 0, EHOSTUNREACH, 0,
ENOPROTOOPT, ECONNREFUSED
};
static int
sysctl_ipforwarding SYSCTL_HANDLER_ARGS
{
#pragma unused(arg1, arg2)
int i, was_ipforwarding = ipforwarding;
i = sysctl_handle_int(oidp, oidp->oid_arg1, oidp->oid_arg2, req);
if (i != 0 || req->newptr == USER_ADDR_NULL) {
return i;
}
if (was_ipforwarding && !ipforwarding) {
/* clean up IPv4 forwarding cached routes */
ifnet_head_lock_shared();
for (i = 0; i <= if_index; i++) {
struct ifnet *ifp = ifindex2ifnet[i];
if (ifp != NULL) {
lck_mtx_lock(&ifp->if_cached_route_lock);
ROUTE_RELEASE(&ifp->if_fwd_route);
bzero(&ifp->if_fwd_route,
sizeof(ifp->if_fwd_route));
lck_mtx_unlock(&ifp->if_cached_route_lock);
}
}
ifnet_head_done();
}
return 0;
}
/*
* Similar to inp_route_{copyout,copyin} routines except that these copy
* out the cached IPv4 forwarding route from struct ifnet instead of the
* inpcb. See comments for those routines for explanations.
*/
static void
ip_fwd_route_copyout(struct ifnet *ifp, struct route *dst)
{
struct route *src = &ifp->if_fwd_route;
lck_mtx_lock_spin(&ifp->if_cached_route_lock);
lck_mtx_convert_spin(&ifp->if_cached_route_lock);
/* Minor sanity check */
if (src->ro_rt != NULL && rt_key(src->ro_rt)->sa_family != AF_INET) {
panic("%s: wrong or corrupted route: %p", __func__, src);
}
route_copyout(dst, src, sizeof(*dst));
lck_mtx_unlock(&ifp->if_cached_route_lock);
}
static void
ip_fwd_route_copyin(struct ifnet *ifp, struct route *src)
{
struct route *dst = &ifp->if_fwd_route;
lck_mtx_lock_spin(&ifp->if_cached_route_lock);
lck_mtx_convert_spin(&ifp->if_cached_route_lock);
/* Minor sanity check */
if (src->ro_rt != NULL && rt_key(src->ro_rt)->sa_family != AF_INET) {
panic("%s: wrong or corrupted route: %p", __func__, src);
}
if (ifp->if_fwd_cacheok) {
route_copyin(src, dst, sizeof(*src));
}
lck_mtx_unlock(&ifp->if_cached_route_lock);
}
/*
* Forward a packet. If some error occurs return the sender
* an icmp packet. Note we can't always generate a meaningful
* icmp message because icmp doesn't have a large enough repertoire
* of codes and types.
*
* If not forwarding, just drop the packet. This could be confusing
* if ipforwarding was zero but some routing protocol was advancing
* us as a gateway to somewhere. However, we must let the routing
* protocol deal with that.
*
* The srcrt parameter indicates whether the packet is being forwarded
* via a source route.
*/
static void
ip_forward(struct mbuf *m, int srcrt, struct sockaddr_in *next_hop)
{
#pragma unused(next_hop)
struct ip *ip = mtod(m, struct ip *);
struct sockaddr_in *sin;
struct rtentry *rt;
struct route fwd_rt;
int error, type = 0, code = 0;
struct mbuf *mcopy;
n_long dest;
struct in_addr pkt_dst;
u_int32_t nextmtu = 0, len;
struct ip_out_args ipoa;
struct ifnet *rcvifp = m->m_pkthdr.rcvif;
bzero(&ipoa, sizeof(ipoa));
ipoa.ipoa_boundif = IFSCOPE_NONE;
ipoa.ipoa_sotc = SO_TC_UNSPEC;
ipoa.ipoa_netsvctype = _NET_SERVICE_TYPE_UNSPEC;
#if IPSEC
struct secpolicy *sp = NULL;
int ipsecerror;
#endif /* IPSEC */
#if PF
struct pf_mtag *pf_mtag;
#endif /* PF */
dest = 0;
pkt_dst = ip->ip_dst;
#if DIAGNOSTIC
if (ipprintfs) {
printf("forward: src %lx dst %lx ttl %x\n",
(u_int32_t)ip->ip_src.s_addr, (u_int32_t)pkt_dst.s_addr,
ip->ip_ttl);
}
#endif
if (m->m_flags & (M_BCAST | M_MCAST) || !in_canforward(pkt_dst)) {
OSAddAtomic(1, &ipstat.ips_cantforward);
m_freem(m);
return;
}
#if IPSTEALTH
if (!ipstealth) {
#endif /* IPSTEALTH */
if (ip->ip_ttl <= IPTTLDEC) {
icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS,
dest, 0);
return;
}
#if IPSTEALTH
}
#endif /* IPSTEALTH */
#if PF
pf_mtag = pf_find_mtag(m);
if (pf_mtag != NULL && pf_mtag->pftag_rtableid != IFSCOPE_NONE) {
ipoa.ipoa_boundif = pf_mtag->pftag_rtableid;
ipoa.ipoa_flags |= IPOAF_BOUND_IF;
}
#endif /* PF */
ip_fwd_route_copyout(rcvifp, &fwd_rt);
sin = SIN(&fwd_rt.ro_dst);
if (ROUTE_UNUSABLE(&fwd_rt) || pkt_dst.s_addr != sin->sin_addr.s_addr) {
ROUTE_RELEASE(&fwd_rt);
sin->sin_family = AF_INET;
sin->sin_len = sizeof(*sin);
sin->sin_addr = pkt_dst;
rtalloc_scoped_ign(&fwd_rt, RTF_PRCLONING, ipoa.ipoa_boundif);
if (fwd_rt.ro_rt == NULL) {
icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, dest, 0);
goto done;
}
}
rt = fwd_rt.ro_rt;
/*
* Save the IP header and at most 8 bytes of the payload,
* in case we need to generate an ICMP message to the src.
*
* We don't use m_copy() because it might return a reference
* to a shared cluster. Both this function and ip_output()
* assume exclusive access to the IP header in `m', so any
* data in a cluster may change before we reach icmp_error().
*/
MGET(mcopy, M_DONTWAIT, m->m_type);
if (mcopy != NULL && m_dup_pkthdr(mcopy, m, M_DONTWAIT) == 0) {
mcopy->m_len = imin((IP_VHL_HL(ip->ip_vhl) << 2) + 8,
(int)ip->ip_len);
m_copydata(m, 0, mcopy->m_len, mtod(mcopy, caddr_t));
}
#if IPSTEALTH
if (!ipstealth) {
#endif /* IPSTEALTH */
ip->ip_ttl -= IPTTLDEC;
#if IPSTEALTH
}
#endif /* IPSTEALTH */
/*
* If forwarding packet using same interface that it came in on,
* perhaps should send a redirect to sender to shortcut a hop.
* Only send redirect if source is sending directly to us,
* and if packet was not source routed (or has any options).
* Also, don't send redirect if forwarding using a default route
* or a route modified by a redirect.
*/
RT_LOCK_SPIN(rt);
if (rt->rt_ifp == m->m_pkthdr.rcvif &&
!(rt->rt_flags & (RTF_DYNAMIC | RTF_MODIFIED)) &&
satosin(rt_key(rt))->sin_addr.s_addr != INADDR_ANY &&
ipsendredirects && !srcrt && rt->rt_ifa != NULL) {
struct in_ifaddr *ia = (struct in_ifaddr *)rt->rt_ifa;
u_int32_t src = ntohl(ip->ip_src.s_addr);
/* Become a regular mutex */
RT_CONVERT_LOCK(rt);
IFA_LOCK_SPIN(&ia->ia_ifa);
if ((src & ia->ia_subnetmask) == ia->ia_subnet) {
if (rt->rt_flags & RTF_GATEWAY) {
dest = satosin(rt->rt_gateway)->sin_addr.s_addr;
} else {
dest = pkt_dst.s_addr;
}
/*
* Router requirements says to only send
* host redirects.
*/
type = ICMP_REDIRECT;
code = ICMP_REDIRECT_HOST;
#if DIAGNOSTIC
if (ipprintfs) {
printf("redirect (%d) to %lx\n", code,
(u_int32_t)dest);
}
#endif
}
IFA_UNLOCK(&ia->ia_ifa);
}
RT_UNLOCK(rt);
/* Mark this packet as being forwarded from another interface */
m->m_pkthdr.pkt_flags |= PKTF_FORWARDED;
len = m_pktlen(m);
error = ip_output(m, NULL, &fwd_rt, IP_FORWARDING | IP_OUTARGS,
NULL, &ipoa);
/* Refresh rt since the route could have changed while in IP */
rt = fwd_rt.ro_rt;
if (error != 0) {
OSAddAtomic(1, &ipstat.ips_cantforward);
} else {
/*
* Increment stats on the source interface; the ones
* for destination interface has been taken care of
* during output above by virtue of PKTF_FORWARDED.
*/
rcvifp->if_fpackets++;
rcvifp->if_fbytes += len;
OSAddAtomic(1, &ipstat.ips_forward);
if (type != 0) {
OSAddAtomic(1, &ipstat.ips_redirectsent);
} else {
if (mcopy != NULL) {
/*
* If we didn't have to go thru ipflow and
* the packet was successfully consumed by
* ip_output, the mcopy is rather a waste;
* this could be further optimized.
*/
m_freem(mcopy);
}
goto done;
}
}
if (mcopy == NULL) {
goto done;
}
switch (error) {
case 0: /* forwarded, but need redirect */
/* type, code set above */
break;
case ENETUNREACH: /* shouldn't happen, checked above */
case EHOSTUNREACH:
case ENETDOWN:
case EHOSTDOWN:
default:
type = ICMP_UNREACH;
code = ICMP_UNREACH_HOST;
break;
case EMSGSIZE:
type = ICMP_UNREACH;
code = ICMP_UNREACH_NEEDFRAG;
if (rt == NULL) {
break;
} else {
RT_LOCK_SPIN(rt);
if (rt->rt_ifp != NULL) {
nextmtu = rt->rt_ifp->if_mtu;
}
RT_UNLOCK(rt);
}
#ifdef IPSEC
if (ipsec_bypass) {
break;
}
/*
* If the packet is routed over IPsec tunnel, tell the
* originator the tunnel MTU.
* tunnel MTU = if MTU - sizeof(IP) - ESP/AH hdrsiz
* XXX quickhack!!!
*/
sp = ipsec4_getpolicybyaddr(mcopy, IPSEC_DIR_OUTBOUND,
IP_FORWARDING, &ipsecerror);
if (sp == NULL) {
break;
}
/*
* find the correct route for outer IPv4
* header, compute tunnel MTU.
*/
nextmtu = 0;
if (sp->req != NULL &&
sp->req->saidx.mode == IPSEC_MODE_TUNNEL) {
struct secasindex saidx;
struct secasvar *sav;
struct route *ro;
struct ip *ipm;
size_t ipsechdr;
/* count IPsec header size */
ipsechdr = ipsec_hdrsiz(sp);
ipm = mtod(mcopy, struct ip *);
bcopy(&sp->req->saidx, &saidx, sizeof(saidx));
saidx.mode = sp->req->saidx.mode;
saidx.reqid = sp->req->saidx.reqid;
sin = SIN(&saidx.src);
if (sin->sin_len == 0) {
sin->sin_len = sizeof(*sin);
sin->sin_family = AF_INET;
sin->sin_port = IPSEC_PORT_ANY;
bcopy(&ipm->ip_src, &sin->sin_addr,
sizeof(sin->sin_addr));
}
sin = SIN(&saidx.dst);
if (sin->sin_len == 0) {
sin->sin_len = sizeof(*sin);
sin->sin_family = AF_INET;
sin->sin_port = IPSEC_PORT_ANY;
bcopy(&ipm->ip_dst, &sin->sin_addr,
sizeof(sin->sin_addr));
}
sav = key_allocsa_policy(&saidx);
if (sav != NULL) {
lck_mtx_lock(sadb_mutex);
if (sav->sah != NULL) {
ro = (struct route *)&sav->sah->sa_route;
if (ro->ro_rt != NULL) {
RT_LOCK(ro->ro_rt);
if (ro->ro_rt->rt_ifp != NULL) {
nextmtu = ro->ro_rt->
rt_ifp->if_mtu;
nextmtu -= ipsechdr;
}
RT_UNLOCK(ro->ro_rt);
}
}
key_freesav(sav, KEY_SADB_LOCKED);
lck_mtx_unlock(sadb_mutex);
}
}
key_freesp(sp, KEY_SADB_UNLOCKED);
#endif /* IPSEC */
break;
case ENOBUFS:
/*
* A router should not generate ICMP_SOURCEQUENCH as
* required in RFC1812 Requirements for IP Version 4 Routers.
* Source quench could be a big problem under DoS attacks,
* or if the underlying interface is rate-limited.
* Those who need source quench packets may re-enable them
* via the net.inet.ip.sendsourcequench sysctl.
*/
if (ip_sendsourcequench == 0) {
m_freem(mcopy);
goto done;
} else {
type = ICMP_SOURCEQUENCH;
code = 0;
}
break;
case EACCES:
m_freem(mcopy);
goto done;
}
if (type == ICMP_UNREACH && code == ICMP_UNREACH_NEEDFRAG) {
OSAddAtomic(1, &ipstat.ips_cantfrag);
}
icmp_error(mcopy, type, code, dest, nextmtu);
done:
ip_fwd_route_copyin(rcvifp, &fwd_rt);
}
int
ip_savecontrol(struct inpcb *inp, struct mbuf **mp, struct ip *ip,
struct mbuf *m)
{
*mp = NULL;
if (inp->inp_socket->so_options & SO_TIMESTAMP) {
struct timeval tv;
getmicrotime(&tv);
mp = sbcreatecontrol_mbuf((caddr_t)&tv, sizeof(tv),
SCM_TIMESTAMP, SOL_SOCKET, mp);
if (*mp == NULL) {
goto no_mbufs;
}
}
if (inp->inp_socket->so_options & SO_TIMESTAMP_MONOTONIC) {
uint64_t time;
time = mach_absolute_time();
mp = sbcreatecontrol_mbuf((caddr_t)&time, sizeof(time),
SCM_TIMESTAMP_MONOTONIC, SOL_SOCKET, mp);
if (*mp == NULL) {
goto no_mbufs;
}
}
if (inp->inp_socket->so_options & SO_TIMESTAMP_CONTINUOUS) {
uint64_t time;
time = mach_continuous_time();
mp = sbcreatecontrol_mbuf((caddr_t)&time, sizeof(time),
SCM_TIMESTAMP_CONTINUOUS, SOL_SOCKET, mp);
if (*mp == NULL) {
goto no_mbufs;
}
}
if (inp->inp_socket->so_flags & SOF_RECV_TRAFFIC_CLASS) {
int tc = m_get_traffic_class(m);
mp = sbcreatecontrol_mbuf((caddr_t)&tc, sizeof(tc),
SO_TRAFFIC_CLASS, SOL_SOCKET, mp);
if (*mp == NULL) {
goto no_mbufs;
}
}
if ((inp->inp_socket->so_flags & SOF_RECV_WAKE_PKT) &&
(m->m_pkthdr.pkt_flags & PKTF_WAKE_PKT)) {
int flag = 1;
mp = sbcreatecontrol_mbuf((caddr_t)&flag, sizeof(flag),
SO_RECV_WAKE_PKT, SOL_SOCKET, mp);
if (*mp == NULL) {
goto no_mbufs;
}
}
if (inp->inp_flags & INP_RECVDSTADDR || SOFLOW_ENABLED(inp->inp_socket)) {
mp = sbcreatecontrol_mbuf((caddr_t)&ip->ip_dst,
sizeof(struct in_addr), IP_RECVDSTADDR, IPPROTO_IP, mp);
if (*mp == NULL) {
goto no_mbufs;
}
}
#ifdef notyet
/*
* XXX
* Moving these out of udp_input() made them even more broken
* than they already were.
*/
/* options were tossed already */
if (inp->inp_flags & INP_RECVOPTS) {
mp = sbcreatecontrol_mbuf((caddr_t)opts_deleted_above,
sizeof(struct in_addr), IP_RECVOPTS, IPPROTO_IP, mp);
if (*mp == NULL) {
goto no_mbufs;
}
}
/* ip_srcroute doesn't do what we want here, need to fix */
if (inp->inp_flags & INP_RECVRETOPTS) {
mp = sbcreatecontrol_mbuf((caddr_t)ip_srcroute(),
sizeof(struct in_addr), IP_RECVRETOPTS, IPPROTO_IP, mp);
if (*mp == NULL) {
goto no_mbufs;
}
}
#endif /* notyet */
if (inp->inp_flags & INP_RECVIF) {
struct ifnet *ifp;
uint8_t sdlbuf[SOCK_MAXADDRLEN + 1];
struct sockaddr_dl *sdl2 = SDL(sdlbuf);
/*
* Make sure to accomodate the largest possible
* size of SA(if_lladdr)->sa_len.
*/
_CASSERT(sizeof(sdlbuf) == (SOCK_MAXADDRLEN + 1));
ifnet_head_lock_shared();
if ((ifp = m->m_pkthdr.rcvif) != NULL &&
ifp->if_index && IF_INDEX_IN_RANGE(ifp->if_index)) {
struct ifaddr *ifa = ifnet_addrs[ifp->if_index - 1];
struct sockaddr_dl *sdp;
if (!ifa || !ifa->ifa_addr) {
goto makedummy;
}
IFA_LOCK_SPIN(ifa);
sdp = SDL(ifa->ifa_addr);
/*
* Change our mind and don't try copy.
*/
if (sdp->sdl_family != AF_LINK) {
IFA_UNLOCK(ifa);
goto makedummy;
}
/* the above _CASSERT ensures sdl_len fits in sdlbuf */
SOCKADDR_COPY(sdp, sdl2, sdp->sdl_len);
IFA_UNLOCK(ifa);
} else {
makedummy:
sdl2->sdl_len =
offsetof(struct sockaddr_dl, sdl_data[0]);
sdl2->sdl_family = AF_LINK;
sdl2->sdl_index = 0;
sdl2->sdl_nlen = sdl2->sdl_alen = sdl2->sdl_slen = 0;
}
ifnet_head_done();
mp = sbcreatecontrol_mbuf((caddr_t)sdl2, sdl2->sdl_len,
IP_RECVIF, IPPROTO_IP, mp);
if (*mp == NULL) {
goto no_mbufs;
}
}
if (inp->inp_flags & INP_RECVTTL) {
mp = sbcreatecontrol_mbuf((caddr_t)&ip->ip_ttl,
sizeof(ip->ip_ttl), IP_RECVTTL, IPPROTO_IP, mp);
if (*mp == NULL) {
goto no_mbufs;
}
}
if (inp->inp_flags & INP_PKTINFO) {
struct in_pktinfo pi;
bzero(&pi, sizeof(struct in_pktinfo));
bcopy(&ip->ip_dst, &pi.ipi_addr, sizeof(struct in_addr));
pi.ipi_ifindex = (m != NULL && m->m_pkthdr.rcvif != NULL) ?
m->m_pkthdr.rcvif->if_index : 0;
mp = sbcreatecontrol_mbuf((caddr_t)&pi,
sizeof(struct in_pktinfo), IP_RECVPKTINFO, IPPROTO_IP, mp);
if (*mp == NULL) {
goto no_mbufs;
}
}
if (inp->inp_flags & INP_RECVTOS) {
mp = sbcreatecontrol_mbuf((caddr_t)&ip->ip_tos,
sizeof(u_char), IP_RECVTOS, IPPROTO_IP, mp);
if (*mp == NULL) {
goto no_mbufs;
}
}
return 0;
no_mbufs:
ipstat.ips_pktdropcntrl++;
return ENOBUFS;
}
static inline u_short
ip_cksum(struct mbuf *m, int hlen)
{
u_short sum;
if (m->m_pkthdr.csum_flags & CSUM_IP_CHECKED) {
sum = !(m->m_pkthdr.csum_flags & CSUM_IP_VALID);
} else if (!(m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) &&
!(m->m_pkthdr.pkt_flags & PKTF_LOOP)) {
/*
* The packet arrived on an interface which isn't capable
* of performing IP header checksum; compute it now.
*/
sum = ip_cksum_hdr_in(m, hlen);
} else {
sum = 0;
m->m_pkthdr.csum_flags |= (CSUM_DATA_VALID | CSUM_PSEUDO_HDR |
CSUM_IP_CHECKED | CSUM_IP_VALID);
m->m_pkthdr.csum_data = 0xffff;
}
if (sum != 0) {
OSAddAtomic(1, &ipstat.ips_badsum);
}
return sum;
}
static int
ip_getstat SYSCTL_HANDLER_ARGS
{
#pragma unused(oidp, arg1, arg2)
if (req->oldptr == USER_ADDR_NULL) {
req->oldlen = (size_t)sizeof(struct ipstat);
}
return SYSCTL_OUT(req, &ipstat, MIN(sizeof(ipstat), req->oldlen));
}
void
ip_setsrcifaddr_info(struct mbuf *m, uint16_t src_idx, struct in_ifaddr *ia)
{
VERIFY(m->m_flags & M_PKTHDR);
/*
* If the source ifaddr is specified, pick up the information
* from there; otherwise just grab the passed-in ifindex as the
* caller may not have the ifaddr available.
*/
if (ia != NULL) {
m->m_pkthdr.pkt_flags |= PKTF_IFAINFO;
m->m_pkthdr.src_ifindex = ia->ia_ifp->if_index;
} else {
m->m_pkthdr.src_ifindex = src_idx;
if (src_idx != 0) {
m->m_pkthdr.pkt_flags |= PKTF_IFAINFO;
}
}
}
void
ip_setdstifaddr_info(struct mbuf *m, uint16_t dst_idx, struct in_ifaddr *ia)
{
VERIFY(m->m_flags & M_PKTHDR);
/*
* If the destination ifaddr is specified, pick up the information
* from there; otherwise just grab the passed-in ifindex as the
* caller may not have the ifaddr available.
*/
if (ia != NULL) {
m->m_pkthdr.pkt_flags |= PKTF_IFAINFO;
m->m_pkthdr.dst_ifindex = ia->ia_ifp->if_index;
} else {
m->m_pkthdr.dst_ifindex = dst_idx;
if (dst_idx != 0) {
m->m_pkthdr.pkt_flags |= PKTF_IFAINFO;
}
}
}
int
ip_getsrcifaddr_info(struct mbuf *m, uint32_t *src_idx, uint32_t *iaf)
{
VERIFY(m->m_flags & M_PKTHDR);
if (!(m->m_pkthdr.pkt_flags & PKTF_IFAINFO)) {
return -1;
}
if (src_idx != NULL) {
*src_idx = m->m_pkthdr.src_ifindex;
}
if (iaf != NULL) {
*iaf = 0;
}
return 0;
}
int
ip_getdstifaddr_info(struct mbuf *m, uint32_t *dst_idx, uint32_t *iaf)
{
VERIFY(m->m_flags & M_PKTHDR);
if (!(m->m_pkthdr.pkt_flags & PKTF_IFAINFO)) {
return -1;
}
if (dst_idx != NULL) {
*dst_idx = m->m_pkthdr.dst_ifindex;
}
if (iaf != NULL) {
*iaf = 0;
}
return 0;
}
/*
* Protocol input handler for IPPROTO_GRE.
*/
void
gre_input(struct mbuf *m, int off)
{
gre_input_func_t fn = gre_input_func;
/*
* If there is a registered GRE input handler, pass mbuf to it.
*/
if (fn != NULL) {
lck_mtx_unlock(inet_domain_mutex);
m = fn(m, off, (mtod(m, struct ip *))->ip_p);
lck_mtx_lock(inet_domain_mutex);
}
/*
* If no matching tunnel that is up is found, we inject
* the mbuf to raw ip socket to see if anyone picks it up.
*/
if (m != NULL) {
rip_input(m, off);
}
}
/*
* Private KPI for PPP/PPTP.
*/
int
ip_gre_register_input(gre_input_func_t fn)
{
lck_mtx_lock(inet_domain_mutex);
gre_input_func = fn;
lck_mtx_unlock(inet_domain_mutex);
return 0;
}
#if (DEBUG || DEVELOPMENT)
static int
sysctl_reset_ip_input_stats SYSCTL_HANDLER_ARGS
{
#pragma unused(arg1, arg2)
int error, i;
i = ip_input_measure;
error = sysctl_handle_int(oidp, &i, 0, req);
if (error || req->newptr == USER_ADDR_NULL) {
goto done;
}
/* impose bounds */
if (i < 0 || i > 1) {
error = EINVAL;
goto done;
}
if (ip_input_measure != i && i == 1) {
net_perf_initialize(&net_perf, ip_input_measure_bins);
}
ip_input_measure = i;
done:
return error;
}
static int
sysctl_ip_input_measure_bins SYSCTL_HANDLER_ARGS
{
#pragma unused(arg1, arg2)
int error;
uint64_t i;
i = ip_input_measure_bins;
error = sysctl_handle_quad(oidp, &i, 0, req);
if (error || req->newptr == USER_ADDR_NULL) {
goto done;
}
/* validate data */
if (!net_perf_validate_bins(i)) {
error = EINVAL;
goto done;
}
ip_input_measure_bins = i;
done:
return error;
}
static int
sysctl_ip_input_getperf SYSCTL_HANDLER_ARGS
{
#pragma unused(oidp, arg1, arg2)
if (req->oldptr == USER_ADDR_NULL) {
req->oldlen = (size_t)sizeof(struct ipstat);
}
return SYSCTL_OUT(req, &net_perf, MIN(sizeof(net_perf), req->oldlen));
}
#endif /* (DEBUG || DEVELOPMENT) */
static int
sysctl_ip_checkinterface SYSCTL_HANDLER_ARGS
{
#pragma unused(arg1, arg2)
int error, i;
i = ip_checkinterface;
error = sysctl_handle_int(oidp, &i, 0, req);
if (error != 0 || req->newptr == USER_ADDR_NULL) {
return error;
}
switch (i) {
case IP_CHECKINTERFACE_WEAK_ES:
case IP_CHECKINTERFACE_HYBRID_ES:
case IP_CHECKINTERFACE_STRONG_ES:
if (ip_checkinterface != i) {
ip_checkinterface = i;
os_log(OS_LOG_DEFAULT, "%s: ip_checkinterface is now %d\n",
__func__, ip_checkinterface);
}
break;
default:
error = EINVAL;
break;
}
return error;
}
Reference in a new issue Copy permalink