gems-kernel/source/THIRDPARTY/xnu/bsd/net/flowadv.c
2024-06-03 11:29:39 -05:00

274 lines
8.5 KiB
C

/*
* Copyright (c) 2012-2021 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@
*/
/*
* Flow Control and Feedback Advisory
*
* Each mbuf that is being sent out through an interface is tagged with a
* unique 32-bit ID which will help to identify all the packets that belong
* to a particular flow at the interface layer. Packets carrying such ID
* would need to be marked with PKTF_FLOW_ID. Normally, this ID is computed
* by the module that generates the flow. There are 3 kinds of flow sources
* that are currently recognized:
*
* a. INPCB (INET/INET6 Protocol Control Block). When a socket is
* connected, the flow hash for the socket is computed and stored in
* the PCB. Further transmissions on the socket will cause the hash
* value to be carried within the mbuf as the flow ID.
*
* b. Interface. When an interface is attached, the flow hash for the
* interface is computed and stored in the ifnet. This value is
* normally ignored for most network drivers, except for those that
* reside atop another driver, e.g. a virtual interface performing
* encapsulation/encryption on the original packet and sending the
* newly-generated packet to another interface. Such interface needs
* to associate all generated packets with the interface flow hash
* value as the flow ID.
*
* c. PF (Packet Filter). When a packet goes through PF and it is not
* already associated with a flow ID, PF will compute a flow hash and
* store it in the packet as flow ID. When the packet is associated
* with a PF state, the state record will have the flow ID stored
* within, in order to avoid recalculating the flow hash. Although PF
* is capable of generating flow IDs, it does not participate in flow
* advisory, and therefore packets whose IDs are computed by PF will
* not have their PKTF_FLOW_ADV packet flag set.
*
* Activation of flow advisory mechanism is done by setting the PKTF_FLOW_ADV
* packet flag; because a flow ID is required, the mechanism will not take
* place unless PKTF_FLOW_ID is set as well. The packet must also carry one
* of the flow source types FLOWSRC_{INPCB,IFNET} in order to identify where
* the flow advisory notification should be delivered to. As noted above,
* FLOWSRC_PF does not participate in this mechanism.
*
* The classq module configured on the interface is responsible for exerting
* flow control to the upper layers. This occurs when the number of packets
* queued for a flow reaches a limit. The module generating the flow will
* cease transmission until further flow advisory notice, and the flow will
* be inserted into the classq's flow control list.
*
* When packets are dequeued from the classq and the number of packets for
* a flow goes below a limit, the classq will transfer its flow control list
* to the global fadv_list. This will then trigger the flow advisory thread
* to run, which will cause the flow source modules to be notified that data
* can now be generated for those previously flow-controlled flows.
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/mcache.h> /* for VERIFY() */
#include <sys/mbuf.h>
#include <sys/proc_internal.h>
#include <sys/socketvar.h>
#include <kern/assert.h>
#include <kern/thread.h>
#include <kern/locks.h>
#include <kern/zalloc.h>
#include <netinet/in_pcb.h>
#include <net/flowadv.h>
#if SKYWALK
#include <skywalk/os_channel.h>
#endif /* SKYWALK */
/* Lock group and attribute for fadv_lock */
static LCK_GRP_DECLARE(fadv_lock_grp, "fadv_lock");
static LCK_MTX_DECLARE(fadv_lock, &fadv_lock_grp);
/* protected by fadv_lock */
static STAILQ_HEAD(fadv_head, flowadv_fcentry) fadv_list =
STAILQ_HEAD_INITIALIZER(fadv_list);
static thread_t fadv_thread = THREAD_NULL;
static uint32_t fadv_active;
#define FADV_CACHE_NAME "flowadv" /* cache name */
static int flowadv_thread_cont(int);
static void flowadv_thread_func(void *, wait_result_t);
void
flowadv_init(void)
{
if (kernel_thread_start(flowadv_thread_func, NULL, &fadv_thread) !=
KERN_SUCCESS) {
panic("%s: couldn't create flow event advisory thread",
__func__);
/* NOTREACHED */
}
thread_deallocate(fadv_thread);
}
struct flowadv_fcentry *
flowadv_alloc_entry(int how)
{
return kalloc_type(struct flowadv_fcentry, how | Z_ZERO);
}
void
flowadv_free_entry(struct flowadv_fcentry *fce)
{
kfree_type(struct flowadv_fcentry, fce);
}
void
flowadv_add(struct flowadv_fclist *fcl)
{
if (STAILQ_EMPTY(fcl)) {
return;
}
lck_mtx_lock_spin(&fadv_lock);
STAILQ_CONCAT(&fadv_list, fcl);
VERIFY(!STAILQ_EMPTY(&fadv_list));
if (!fadv_active && fadv_thread != THREAD_NULL) {
wakeup_one((caddr_t)&fadv_list);
}
lck_mtx_unlock(&fadv_lock);
}
void
flowadv_add_entry(struct flowadv_fcentry *fce)
{
lck_mtx_lock_spin(&fadv_lock);
STAILQ_INSERT_HEAD(&fadv_list, fce, fce_link);
VERIFY(!STAILQ_EMPTY(&fadv_list));
if (!fadv_active && fadv_thread != THREAD_NULL) {
wakeup_one((caddr_t)&fadv_list);
}
lck_mtx_unlock(&fadv_lock);
}
static int
flowadv_thread_cont(int err)
{
#pragma unused(err)
for (;;) {
LCK_MTX_ASSERT(&fadv_lock, LCK_MTX_ASSERT_OWNED);
while (STAILQ_EMPTY(&fadv_list)) {
VERIFY(!fadv_active);
(void) msleep0(&fadv_list, &fadv_lock, (PSOCK | PSPIN),
"flowadv_cont", 0, flowadv_thread_cont);
/* NOTREACHED */
}
fadv_active = 1;
for (;;) {
struct flowadv_fcentry *fce;
VERIFY(!STAILQ_EMPTY(&fadv_list));
fce = STAILQ_FIRST(&fadv_list);
STAILQ_REMOVE(&fadv_list, fce,
flowadv_fcentry, fce_link);
STAILQ_NEXT(fce, fce_link) = NULL;
lck_mtx_unlock(&fadv_lock);
if (fce->fce_event_type == FCE_EVENT_TYPE_CONGESTION_EXPERIENCED) {
switch (fce->fce_flowsrc_type) {
case FLOWSRC_CHANNEL:
kern_channel_flowadv_report_ce_event(fce, fce->fce_ce_cnt,
fce->fce_pkts_since_last_report);
break;
case FLOWSRC_INPCB:
case FLOWSRC_IFNET:
case FLOWSRC_PF:
default:
break;
}
goto next;
}
switch (fce->fce_flowsrc_type) {
case FLOWSRC_INPCB:
inp_flowadv(fce->fce_flowid);
break;
case FLOWSRC_IFNET:
#if SKYWALK
/*
* when using the flowID allocator, IPSec
* driver uses the "pkt_flowid" field in mbuf
* packet header for the globally unique flowID
* and the "pkt_mpriv_srcid" field carries the
* interface flow control id (if_flowhash).
* For IPSec flows, it is the IPSec driver
* network interface which is flow controlled,
* instead of the IPSec SA flow.
*/
ifnet_flowadv(fce->fce_flowsrc_token);
#else /* !SKYWALK */
ifnet_flowadv(fce->fce_flowid);
#endif /* !SKYWALK */
break;
#if SKYWALK
case FLOWSRC_CHANNEL:
kern_channel_flowadv_clear(fce);
break;
#endif /* SKYWALK */
case FLOWSRC_PF:
default:
break;
}
next:
flowadv_free_entry(fce);
lck_mtx_lock_spin(&fadv_lock);
/* if there's no pending request, we're done */
if (STAILQ_EMPTY(&fadv_list)) {
break;
}
}
fadv_active = 0;
}
}
__dead2
static void
flowadv_thread_func(void *v, wait_result_t w)
{
#pragma unused(v, w)
lck_mtx_lock(&fadv_lock);
(void) msleep0(&fadv_list, &fadv_lock, (PSOCK | PSPIN),
"flowadv", 0, flowadv_thread_cont);
/*
* msleep0() shouldn't have returned as PCATCH was not set;
* therefore assert in this case.
*/
lck_mtx_unlock(&fadv_lock);
VERIFY(0);
}