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freebsd-nq/sys/netinet/tcp_subr.c
John Baldwin ce39811544 Save the current TCP pacing rate in t_pacing_rate. 
Reviewed by:	gallatin, gnn
Sponsored by:	Netflix
Differential Revision:	https://reviews.freebsd.org/D26875
2020-10-29 00:03:19 +00:00

3508 lines
92 KiB
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/*-
* SPDX-License-Identifier: BSD-3-Clause
*
* Copyright (c) 1982, 1986, 1988, 1990, 1993, 1995
* 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. 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.
*
* @(#)tcp_subr.c 8.2 (Berkeley) 5/24/95
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_inet.h"
#include "opt_inet6.h"
#include "opt_ipsec.h"
#include "opt_kern_tls.h"
#include "opt_tcpdebug.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/arb.h>
#include <sys/callout.h>
#include <sys/eventhandler.h>
#ifdef TCP_HHOOK
#include <sys/hhook.h>
#endif
#include <sys/kernel.h>
#ifdef TCP_HHOOK
#include <sys/khelp.h>
#endif
#ifdef KERN_TLS
#include <sys/ktls.h>
#endif
#include <sys/qmath.h>
#include <sys/stats.h>
#include <sys/sysctl.h>
#include <sys/jail.h>
#include <sys/malloc.h>
#include <sys/refcount.h>
#include <sys/mbuf.h>
#ifdef INET6
#include <sys/domain.h>
#endif
#include <sys/priv.h>
#include <sys/proc.h>
#include <sys/sdt.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/protosw.h>
#include <sys/random.h>
#include <vm/uma.h>
#include <net/route.h>
#include <net/route/nhop.h>
#include <net/if.h>
#include <net/if_var.h>
#include <net/vnet.h>
#include <netinet/in.h>
#include <netinet/in_fib.h>
#include <netinet/in_kdtrace.h>
#include <netinet/in_pcb.h>
#include <netinet/in_systm.h>
#include <netinet/in_var.h>
#include <netinet/ip.h>
#include <netinet/ip_icmp.h>
#include <netinet/ip_var.h>
#ifdef INET6
#include <netinet/icmp6.h>
#include <netinet/ip6.h>
#include <netinet6/in6_fib.h>
#include <netinet6/in6_pcb.h>
#include <netinet6/ip6_var.h>
#include <netinet6/scope6_var.h>
#include <netinet6/nd6.h>
#endif
#include <netinet/tcp.h>
#include <netinet/tcp_fsm.h>
#include <netinet/tcp_seq.h>
#include <netinet/tcp_timer.h>
#include <netinet/tcp_var.h>
#include <netinet/tcp_log_buf.h>
#include <netinet/tcp_syncache.h>
#include <netinet/tcp_hpts.h>
#include <netinet/cc/cc.h>
#ifdef INET6
#include <netinet6/tcp6_var.h>
#endif
#include <netinet/tcpip.h>
#include <netinet/tcp_fastopen.h>
#ifdef TCPPCAP
#include <netinet/tcp_pcap.h>
#endif
#ifdef TCPDEBUG
#include <netinet/tcp_debug.h>
#endif
#ifdef INET6
#include <netinet6/ip6protosw.h>
#endif
#ifdef TCP_OFFLOAD
#include <netinet/tcp_offload.h>
#endif
#include <netipsec/ipsec_support.h>
#include <machine/in_cksum.h>
#include <crypto/siphash/siphash.h>
#include <security/mac/mac_framework.h>
VNET_DEFINE(int, tcp_mssdflt) = TCP_MSS;
#ifdef INET6
VNET_DEFINE(int, tcp_v6mssdflt) = TCP6_MSS;
#endif
#ifdef NETFLIX_EXP_DETECTION
/* Sack attack detection thresholds and such */
SYSCTL_NODE(_net_inet_tcp, OID_AUTO, sack_attack,
CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
"Sack Attack detection thresholds");
int32_t tcp_force_detection = 0;
SYSCTL_INT(_net_inet_tcp_sack_attack, OID_AUTO, force_detection,
CTLFLAG_RW,
&tcp_force_detection, 0,
"Do we force detection even if the INP has it off?");
int32_t tcp_sack_to_ack_thresh = 700; /* 70 % */
SYSCTL_INT(_net_inet_tcp_sack_attack, OID_AUTO, sack_to_ack_thresh,
CTLFLAG_RW,
&tcp_sack_to_ack_thresh, 700,
"Percentage of sacks to acks we must see above (10.1 percent is 101)?");
int32_t tcp_sack_to_move_thresh = 600; /* 60 % */
SYSCTL_INT(_net_inet_tcp_sack_attack, OID_AUTO, move_thresh,
CTLFLAG_RW,
&tcp_sack_to_move_thresh, 600,
"Percentage of sack moves we must see above (10.1 percent is 101)");
int32_t tcp_restoral_thresh = 650; /* 65 % (sack:2:ack -5%) */
SYSCTL_INT(_net_inet_tcp_sack_attack, OID_AUTO, restore_thresh,
CTLFLAG_RW,
&tcp_restoral_thresh, 550,
"Percentage of sack to ack percentage we must see below to restore(10.1 percent is 101)");
int32_t tcp_sad_decay_val = 800;
SYSCTL_INT(_net_inet_tcp_sack_attack, OID_AUTO, decay_per,
CTLFLAG_RW,
&tcp_sad_decay_val, 800,
"The decay percentage (10.1 percent equals 101 )");
int32_t tcp_map_minimum = 500;
SYSCTL_INT(_net_inet_tcp_sack_attack, OID_AUTO, nummaps,
CTLFLAG_RW,
&tcp_map_minimum, 500,
"Number of Map enteries before we start detection");
int32_t tcp_attack_on_turns_on_logging = 0;
SYSCTL_INT(_net_inet_tcp_sack_attack, OID_AUTO, attacks_logged,
CTLFLAG_RW,
&tcp_attack_on_turns_on_logging, 0,
"When we have a positive hit on attack, do we turn on logging?");
int32_t tcp_sad_pacing_interval = 2000;
SYSCTL_INT(_net_inet_tcp_sack_attack, OID_AUTO, sad_pacing_int,
CTLFLAG_RW,
&tcp_sad_pacing_interval, 2000,
"What is the minimum pacing interval for a classified attacker?");
int32_t tcp_sad_low_pps = 100;
SYSCTL_INT(_net_inet_tcp_sack_attack, OID_AUTO, sad_low_pps,
CTLFLAG_RW,
&tcp_sad_low_pps, 100,
"What is the input pps that below which we do not decay?");
#endif
struct rwlock tcp_function_lock;
static int
sysctl_net_inet_tcp_mss_check(SYSCTL_HANDLER_ARGS)
{
int error, new;
new = V_tcp_mssdflt;
error = sysctl_handle_int(oidp, &new, 0, req);
if (error == 0 && req->newptr) {
if (new < TCP_MINMSS)
error = EINVAL;
else
V_tcp_mssdflt = new;
}
return (error);
}
SYSCTL_PROC(_net_inet_tcp, TCPCTL_MSSDFLT, mssdflt,
CTLFLAG_VNET | CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_NEEDGIANT,
&VNET_NAME(tcp_mssdflt), 0, &sysctl_net_inet_tcp_mss_check, "I",
"Default TCP Maximum Segment Size");
#ifdef INET6
static int
sysctl_net_inet_tcp_mss_v6_check(SYSCTL_HANDLER_ARGS)
{
int error, new;
new = V_tcp_v6mssdflt;
error = sysctl_handle_int(oidp, &new, 0, req);
if (error == 0 && req->newptr) {
if (new < TCP_MINMSS)
error = EINVAL;
else
V_tcp_v6mssdflt = new;
}
return (error);
}
SYSCTL_PROC(_net_inet_tcp, TCPCTL_V6MSSDFLT, v6mssdflt,
CTLFLAG_VNET | CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_NEEDGIANT,
&VNET_NAME(tcp_v6mssdflt), 0, &sysctl_net_inet_tcp_mss_v6_check, "I",
"Default TCP Maximum Segment Size for IPv6");
#endif /* INET6 */
/*
* Minimum MSS we accept and use. This prevents DoS attacks where
* we are forced to a ridiculous low MSS like 20 and send hundreds
* of packets instead of one. The effect scales with the available
* bandwidth and quickly saturates the CPU and network interface
* with packet generation and sending. Set to zero to disable MINMSS
* checking. This setting prevents us from sending too small packets.
*/
VNET_DEFINE(int, tcp_minmss) = TCP_MINMSS;
SYSCTL_INT(_net_inet_tcp, OID_AUTO, minmss, CTLFLAG_VNET | CTLFLAG_RW,
&VNET_NAME(tcp_minmss), 0,
"Minimum TCP Maximum Segment Size");
VNET_DEFINE(int, tcp_do_rfc1323) = 1;
SYSCTL_INT(_net_inet_tcp, TCPCTL_DO_RFC1323, rfc1323, CTLFLAG_VNET | CTLFLAG_RW,
&VNET_NAME(tcp_do_rfc1323), 0,
"Enable rfc1323 (high performance TCP) extensions");
VNET_DEFINE(int, tcp_ts_offset_per_conn) = 1;
SYSCTL_INT(_net_inet_tcp, OID_AUTO, ts_offset_per_conn, CTLFLAG_VNET | CTLFLAG_RW,
&VNET_NAME(tcp_ts_offset_per_conn), 0,
"Initialize TCP timestamps per connection instead of per host pair");
static int tcp_log_debug = 0;
SYSCTL_INT(_net_inet_tcp, OID_AUTO, log_debug, CTLFLAG_RW,
&tcp_log_debug, 0, "Log errors caused by incoming TCP segments");
static int tcp_tcbhashsize;
SYSCTL_INT(_net_inet_tcp, OID_AUTO, tcbhashsize, CTLFLAG_RDTUN | CTLFLAG_NOFETCH,
&tcp_tcbhashsize, 0, "Size of TCP control-block hashtable");
static int do_tcpdrain = 1;
SYSCTL_INT(_net_inet_tcp, OID_AUTO, do_tcpdrain, CTLFLAG_RW, &do_tcpdrain, 0,
"Enable tcp_drain routine for extra help when low on mbufs");
SYSCTL_UINT(_net_inet_tcp, OID_AUTO, pcbcount, CTLFLAG_VNET | CTLFLAG_RD,
&VNET_NAME(tcbinfo.ipi_count), 0, "Number of active PCBs");
VNET_DEFINE_STATIC(int, icmp_may_rst) = 1;
#define V_icmp_may_rst VNET(icmp_may_rst)
SYSCTL_INT(_net_inet_tcp, OID_AUTO, icmp_may_rst, CTLFLAG_VNET | CTLFLAG_RW,
&VNET_NAME(icmp_may_rst), 0,
"Certain ICMP unreachable messages may abort connections in SYN_SENT");
VNET_DEFINE_STATIC(int, tcp_isn_reseed_interval) = 0;
#define V_tcp_isn_reseed_interval VNET(tcp_isn_reseed_interval)
SYSCTL_INT(_net_inet_tcp, OID_AUTO, isn_reseed_interval, CTLFLAG_VNET | CTLFLAG_RW,
&VNET_NAME(tcp_isn_reseed_interval), 0,
"Seconds between reseeding of ISN secret");
static int tcp_soreceive_stream;
SYSCTL_INT(_net_inet_tcp, OID_AUTO, soreceive_stream, CTLFLAG_RDTUN,
&tcp_soreceive_stream, 0, "Using soreceive_stream for TCP sockets");
VNET_DEFINE(uma_zone_t, sack_hole_zone);
#define V_sack_hole_zone VNET(sack_hole_zone)
VNET_DEFINE(uint32_t, tcp_map_entries_limit) = 0; /* unlimited */
static int
sysctl_net_inet_tcp_map_limit_check(SYSCTL_HANDLER_ARGS)
{
int error;
uint32_t new;
new = V_tcp_map_entries_limit;
error = sysctl_handle_int(oidp, &new, 0, req);
if (error == 0 && req->newptr) {
/* only allow "0" and value > minimum */
if (new > 0 && new < TCP_MIN_MAP_ENTRIES_LIMIT)
error = EINVAL;
else
V_tcp_map_entries_limit = new;
}
return (error);
}
SYSCTL_PROC(_net_inet_tcp, OID_AUTO, map_limit,
CTLFLAG_VNET | CTLTYPE_UINT | CTLFLAG_RW | CTLFLAG_NEEDGIANT,
&VNET_NAME(tcp_map_entries_limit), 0,
&sysctl_net_inet_tcp_map_limit_check, "IU",
"Total sendmap entries limit");
VNET_DEFINE(uint32_t, tcp_map_split_limit) = 0; /* unlimited */
SYSCTL_UINT(_net_inet_tcp, OID_AUTO, split_limit, CTLFLAG_VNET | CTLFLAG_RW,
&VNET_NAME(tcp_map_split_limit), 0,
"Total sendmap split entries limit");
#ifdef TCP_HHOOK
VNET_DEFINE(struct hhook_head *, tcp_hhh[HHOOK_TCP_LAST+1]);
#endif
#define TS_OFFSET_SECRET_LENGTH SIPHASH_KEY_LENGTH
VNET_DEFINE_STATIC(u_char, ts_offset_secret[TS_OFFSET_SECRET_LENGTH]);
#define V_ts_offset_secret VNET(ts_offset_secret)
static int tcp_default_fb_init(struct tcpcb *tp);
static void tcp_default_fb_fini(struct tcpcb *tp, int tcb_is_purged);
static int tcp_default_handoff_ok(struct tcpcb *tp);
static struct inpcb *tcp_notify(struct inpcb *, int);
static struct inpcb *tcp_mtudisc_notify(struct inpcb *, int);
static void tcp_mtudisc(struct inpcb *, int);
static char * tcp_log_addr(struct in_conninfo *inc, struct tcphdr *th,
void *ip4hdr, const void *ip6hdr);
static struct tcp_function_block tcp_def_funcblk = {
.tfb_tcp_block_name = "freebsd",
.tfb_tcp_output = tcp_output,
.tfb_tcp_do_segment = tcp_do_segment,
.tfb_tcp_ctloutput = tcp_default_ctloutput,
.tfb_tcp_handoff_ok = tcp_default_handoff_ok,
.tfb_tcp_fb_init = tcp_default_fb_init,
.tfb_tcp_fb_fini = tcp_default_fb_fini,
};
static int tcp_fb_cnt = 0;
struct tcp_funchead t_functions;
static struct tcp_function_block *tcp_func_set_ptr = &tcp_def_funcblk;
static struct tcp_function_block *
find_tcp_functions_locked(struct tcp_function_set *fs)
{
struct tcp_function *f;
struct tcp_function_block *blk=NULL;
TAILQ_FOREACH(f, &t_functions, tf_next) {
if (strcmp(f->tf_name, fs->function_set_name) == 0) {
blk = f->tf_fb;
break;
}
}
return(blk);
}
static struct tcp_function_block *
find_tcp_fb_locked(struct tcp_function_block *blk, struct tcp_function **s)
{
struct tcp_function_block *rblk=NULL;
struct tcp_function *f;
TAILQ_FOREACH(f, &t_functions, tf_next) {
if (f->tf_fb == blk) {
rblk = blk;
if (s) {
*s = f;
}
break;
}
}
return (rblk);
}
struct tcp_function_block *
find_and_ref_tcp_functions(struct tcp_function_set *fs)
{
struct tcp_function_block *blk;
rw_rlock(&tcp_function_lock);
blk = find_tcp_functions_locked(fs);
if (blk)
refcount_acquire(&blk->tfb_refcnt);
rw_runlock(&tcp_function_lock);
return(blk);
}
struct tcp_function_block *
find_and_ref_tcp_fb(struct tcp_function_block *blk)
{
struct tcp_function_block *rblk;
rw_rlock(&tcp_function_lock);
rblk = find_tcp_fb_locked(blk, NULL);
if (rblk)
refcount_acquire(&rblk->tfb_refcnt);
rw_runlock(&tcp_function_lock);
return(rblk);
}
static struct tcp_function_block *
find_and_ref_tcp_default_fb(void)
{
struct tcp_function_block *rblk;
rw_rlock(&tcp_function_lock);
rblk = tcp_func_set_ptr;
refcount_acquire(&rblk->tfb_refcnt);
rw_runlock(&tcp_function_lock);
return (rblk);
}
void
tcp_switch_back_to_default(struct tcpcb *tp)
{
struct tcp_function_block *tfb;
KASSERT(tp->t_fb != &tcp_def_funcblk,
("%s: called by the built-in default stack", __func__));
/*
* Release the old stack. This function will either find a new one
* or panic.
*/
if (tp->t_fb->tfb_tcp_fb_fini != NULL)
(*tp->t_fb->tfb_tcp_fb_fini)(tp, 0);
refcount_release(&tp->t_fb->tfb_refcnt);
/*
* Now, we'll find a new function block to use.
* Start by trying the current user-selected
* default, unless this stack is the user-selected
* default.
*/
tfb = find_and_ref_tcp_default_fb();
if (tfb == tp->t_fb) {
refcount_release(&tfb->tfb_refcnt);
tfb = NULL;
}
/* Does the stack accept this connection? */
if (tfb != NULL && tfb->tfb_tcp_handoff_ok != NULL &&
(*tfb->tfb_tcp_handoff_ok)(tp)) {
refcount_release(&tfb->tfb_refcnt);
tfb = NULL;
}
/* Try to use that stack. */
if (tfb != NULL) {
/* Initialize the new stack. If it succeeds, we are done. */
tp->t_fb = tfb;
if (tp->t_fb->tfb_tcp_fb_init == NULL ||
(*tp->t_fb->tfb_tcp_fb_init)(tp) == 0)
return;
/*
* Initialization failed. Release the reference count on
* the stack.
*/
refcount_release(&tfb->tfb_refcnt);
}
/*
* If that wasn't feasible, use the built-in default
* stack which is not allowed to reject anyone.
*/
tfb = find_and_ref_tcp_fb(&tcp_def_funcblk);
if (tfb == NULL) {
/* there always should be a default */
panic("Can't refer to tcp_def_funcblk");
}
if (tfb->tfb_tcp_handoff_ok != NULL) {
if ((*tfb->tfb_tcp_handoff_ok) (tp)) {
/* The default stack cannot say no */
panic("Default stack rejects a new session?");
}
}
tp->t_fb = tfb;
if (tp->t_fb->tfb_tcp_fb_init != NULL &&
(*tp->t_fb->tfb_tcp_fb_init)(tp)) {
/* The default stack cannot fail */
panic("Default stack initialization failed");
}
}
static int
sysctl_net_inet_default_tcp_functions(SYSCTL_HANDLER_ARGS)
{
int error=ENOENT;
struct tcp_function_set fs;
struct tcp_function_block *blk;
memset(&fs, 0, sizeof(fs));
rw_rlock(&tcp_function_lock);
blk = find_tcp_fb_locked(tcp_func_set_ptr, NULL);
if (blk) {
/* Found him */
strcpy(fs.function_set_name, blk->tfb_tcp_block_name);
fs.pcbcnt = blk->tfb_refcnt;
}
rw_runlock(&tcp_function_lock);
error = sysctl_handle_string(oidp, fs.function_set_name,
sizeof(fs.function_set_name), req);
/* Check for error or no change */
if (error != 0 || req->newptr == NULL)
return(error);
rw_wlock(&tcp_function_lock);
blk = find_tcp_functions_locked(&fs);
if ((blk == NULL) ||
(blk->tfb_flags & TCP_FUNC_BEING_REMOVED)) {
error = ENOENT;
goto done;
}
tcp_func_set_ptr = blk;
done:
rw_wunlock(&tcp_function_lock);
return (error);
}
SYSCTL_PROC(_net_inet_tcp, OID_AUTO, functions_default,
CTLTYPE_STRING | CTLFLAG_RW | CTLFLAG_NEEDGIANT,
NULL, 0, sysctl_net_inet_default_tcp_functions, "A",
"Set/get the default TCP functions");
static int
sysctl_net_inet_list_available(SYSCTL_HANDLER_ARGS)
{
int error, cnt, linesz;
struct tcp_function *f;
char *buffer, *cp;
size_t bufsz, outsz;
bool alias;
cnt = 0;
rw_rlock(&tcp_function_lock);
TAILQ_FOREACH(f, &t_functions, tf_next) {
cnt++;
}
rw_runlock(&tcp_function_lock);
bufsz = (cnt+2) * ((TCP_FUNCTION_NAME_LEN_MAX * 2) + 13) + 1;
buffer = malloc(bufsz, M_TEMP, M_WAITOK);
error = 0;
cp = buffer;
linesz = snprintf(cp, bufsz, "\n%-32s%c %-32s %s\n", "Stack", 'D',
"Alias", "PCB count");
cp += linesz;
bufsz -= linesz;
outsz = linesz;
rw_rlock(&tcp_function_lock);
TAILQ_FOREACH(f, &t_functions, tf_next) {
alias = (f->tf_name != f->tf_fb->tfb_tcp_block_name);
linesz = snprintf(cp, bufsz, "%-32s%c %-32s %u\n",
f->tf_fb->tfb_tcp_block_name,
(f->tf_fb == tcp_func_set_ptr) ? '*' : ' ',
alias ? f->tf_name : "-",
f->tf_fb->tfb_refcnt);
if (linesz >= bufsz) {
error = EOVERFLOW;
break;
}
cp += linesz;
bufsz -= linesz;
outsz += linesz;
}
rw_runlock(&tcp_function_lock);
if (error == 0)
error = sysctl_handle_string(oidp, buffer, outsz + 1, req);
free(buffer, M_TEMP);
return (error);
}
SYSCTL_PROC(_net_inet_tcp, OID_AUTO, functions_available,
CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_NEEDGIANT,
NULL, 0, sysctl_net_inet_list_available, "A",
"list available TCP Function sets");
/*
* Exports one (struct tcp_function_info) for each alias/name.
*/
static int
sysctl_net_inet_list_func_info(SYSCTL_HANDLER_ARGS)
{
int cnt, error;
struct tcp_function *f;
struct tcp_function_info tfi;
/*
* We don't allow writes.
*/
if (req->newptr != NULL)
return (EINVAL);
/*
* Wire the old buffer so we can directly copy the functions to
* user space without dropping the lock.
*/
if (req->oldptr != NULL) {
error = sysctl_wire_old_buffer(req, 0);
if (error)
return (error);
}
/*
* Walk the list and copy out matching entries. If INVARIANTS
* is compiled in, also walk the list to verify the length of
* the list matches what we have recorded.
*/
rw_rlock(&tcp_function_lock);
cnt = 0;
#ifndef INVARIANTS
if (req->oldptr == NULL) {
cnt = tcp_fb_cnt;
goto skip_loop;
}
#endif
TAILQ_FOREACH(f, &t_functions, tf_next) {
#ifdef INVARIANTS
cnt++;
#endif
if (req->oldptr != NULL) {
bzero(&tfi, sizeof(tfi));
tfi.tfi_refcnt = f->tf_fb->tfb_refcnt;
tfi.tfi_id = f->tf_fb->tfb_id;
(void)strlcpy(tfi.tfi_alias, f->tf_name,
sizeof(tfi.tfi_alias));
(void)strlcpy(tfi.tfi_name,
f->tf_fb->tfb_tcp_block_name, sizeof(tfi.tfi_name));
error = SYSCTL_OUT(req, &tfi, sizeof(tfi));
/*
* Don't stop on error, as that is the
* mechanism we use to accumulate length
* information if the buffer was too short.
*/
}
}
KASSERT(cnt == tcp_fb_cnt,
("%s: cnt (%d) != tcp_fb_cnt (%d)", __func__, cnt, tcp_fb_cnt));
#ifndef INVARIANTS
skip_loop:
#endif
rw_runlock(&tcp_function_lock);
if (req->oldptr == NULL)
error = SYSCTL_OUT(req, NULL,
(cnt + 1) * sizeof(struct tcp_function_info));
return (error);
}
SYSCTL_PROC(_net_inet_tcp, OID_AUTO, function_info,
CTLTYPE_OPAQUE | CTLFLAG_SKIP | CTLFLAG_RD | CTLFLAG_MPSAFE,
NULL, 0, sysctl_net_inet_list_func_info, "S,tcp_function_info",
"List TCP function block name-to-ID mappings");
/*
* tfb_tcp_handoff_ok() function for the default stack.
* Note that we'll basically try to take all comers.
*/
static int
tcp_default_handoff_ok(struct tcpcb *tp)
{
return (0);
}
/*
* tfb_tcp_fb_init() function for the default stack.
*
* This handles making sure we have appropriate timers set if you are
* transitioning a socket that has some amount of setup done.
*
* The init() fuction from the default can *never* return non-zero i.e.
* it is required to always succeed since it is the stack of last resort!
*/
static int
tcp_default_fb_init(struct tcpcb *tp)
{
struct socket *so;
INP_WLOCK_ASSERT(tp->t_inpcb);
KASSERT(tp->t_state >= 0 && tp->t_state < TCPS_TIME_WAIT,
("%s: connection %p in unexpected state %d", __func__, tp,
tp->t_state));
/*
* Nothing to do for ESTABLISHED or LISTEN states. And, we don't
* know what to do for unexpected states (which includes TIME_WAIT).
*/
if (tp->t_state <= TCPS_LISTEN || tp->t_state >= TCPS_TIME_WAIT)
return (0);
/*
* Make sure some kind of transmission timer is set if there is
* outstanding data.
*/
so = tp->t_inpcb->inp_socket;
if ((!TCPS_HAVEESTABLISHED(tp->t_state) || sbavail(&so->so_snd) ||
tp->snd_una != tp->snd_max) && !(tcp_timer_active(tp, TT_REXMT) ||
tcp_timer_active(tp, TT_PERSIST))) {
/*
* If the session has established and it looks like it should
* be in the persist state, set the persist timer. Otherwise,
* set the retransmit timer.
*/
if (TCPS_HAVEESTABLISHED(tp->t_state) && tp->snd_wnd == 0 &&
(int32_t)(tp->snd_nxt - tp->snd_una) <
(int32_t)sbavail(&so->so_snd))
tcp_setpersist(tp);
else
tcp_timer_activate(tp, TT_REXMT, tp->t_rxtcur);
}
/* All non-embryonic sessions get a keepalive timer. */
if (!tcp_timer_active(tp, TT_KEEP))
tcp_timer_activate(tp, TT_KEEP,
TCPS_HAVEESTABLISHED(tp->t_state) ? TP_KEEPIDLE(tp) :
TP_KEEPINIT(tp));
return (0);
}
/*
* tfb_tcp_fb_fini() function for the default stack.
*
* This changes state as necessary (or prudent) to prepare for another stack
* to assume responsibility for the connection.
*/
static void
tcp_default_fb_fini(struct tcpcb *tp, int tcb_is_purged)
{
INP_WLOCK_ASSERT(tp->t_inpcb);
return;
}
/*
* Target size of TCP PCB hash tables. Must be a power of two.
*
* Note that this can be overridden by the kernel environment
* variable net.inet.tcp.tcbhashsize
*/
#ifndef TCBHASHSIZE
#define TCBHASHSIZE 0
#endif
/*
* XXX
* Callouts should be moved into struct tcp directly. They are currently
* separate because the tcpcb structure is exported to userland for sysctl
* parsing purposes, which do not know about callouts.
*/
struct tcpcb_mem {
struct tcpcb tcb;
struct tcp_timer tt;
struct cc_var ccv;
#ifdef TCP_HHOOK
struct osd osd;
#endif
};
VNET_DEFINE_STATIC(uma_zone_t, tcpcb_zone);
#define V_tcpcb_zone VNET(tcpcb_zone)
MALLOC_DEFINE(M_TCPLOG, "tcplog", "TCP address and flags print buffers");
MALLOC_DEFINE(M_TCPFUNCTIONS, "tcpfunc", "TCP function set memory");
static struct mtx isn_mtx;
#define ISN_LOCK_INIT() mtx_init(&isn_mtx, "isn_mtx", NULL, MTX_DEF)
#define ISN_LOCK() mtx_lock(&isn_mtx)
#define ISN_UNLOCK() mtx_unlock(&isn_mtx)
/*
* TCP initialization.
*/
static void
tcp_zone_change(void *tag)
{
uma_zone_set_max(V_tcbinfo.ipi_zone, maxsockets);
uma_zone_set_max(V_tcpcb_zone, maxsockets);
tcp_tw_zone_change();
}
static int
tcp_inpcb_init(void *mem, int size, int flags)
{
struct inpcb *inp = mem;
INP_LOCK_INIT(inp, "inp", "tcpinp");
return (0);
}
/*
* Take a value and get the next power of 2 that doesn't overflow.
* Used to size the tcp_inpcb hash buckets.
*/
static int
maketcp_hashsize(int size)
{
int hashsize;
/*
* auto tune.
* get the next power of 2 higher than maxsockets.
*/
hashsize = 1 << fls(size);
/* catch overflow, and just go one power of 2 smaller */
if (hashsize < size) {
hashsize = 1 << (fls(size) - 1);
}
return (hashsize);
}
static volatile int next_tcp_stack_id = 1;
/*
* Register a TCP function block with the name provided in the names
* array. (Note that this function does NOT automatically register
* blk->tfb_tcp_block_name as a stack name. Therefore, you should
* explicitly include blk->tfb_tcp_block_name in the list of names if
* you wish to register the stack with that name.)
*
* Either all name registrations will succeed or all will fail. If
* a name registration fails, the function will update the num_names
* argument to point to the array index of the name that encountered
* the failure.
*
* Returns 0 on success, or an error code on failure.
*/
int
register_tcp_functions_as_names(struct tcp_function_block *blk, int wait,
const char *names[], int *num_names)
{
struct tcp_function *n;
struct tcp_function_set fs;
int error, i;
KASSERT(names != NULL && *num_names > 0,
("%s: Called with 0-length name list", __func__));
KASSERT(names != NULL, ("%s: Called with NULL name list", __func__));
KASSERT(rw_initialized(&tcp_function_lock),
("%s: called too early", __func__));
if ((blk->tfb_tcp_output == NULL) ||
(blk->tfb_tcp_do_segment == NULL) ||
(blk->tfb_tcp_ctloutput == NULL) ||
(strlen(blk->tfb_tcp_block_name) == 0)) {
/*
* These functions are required and you
* need a name.
*/
*num_names = 0;
return (EINVAL);
}
if (blk->tfb_tcp_timer_stop_all ||
blk->tfb_tcp_timer_activate ||
blk->tfb_tcp_timer_active ||
blk->tfb_tcp_timer_stop) {
/*
* If you define one timer function you
* must have them all.
*/
if ((blk->tfb_tcp_timer_stop_all == NULL) ||
(blk->tfb_tcp_timer_activate == NULL) ||
(blk->tfb_tcp_timer_active == NULL) ||
(blk->tfb_tcp_timer_stop == NULL)) {
*num_names = 0;
return (EINVAL);
}
}
if (blk->tfb_flags & TCP_FUNC_BEING_REMOVED) {
*num_names = 0;
return (EINVAL);
}
refcount_init(&blk->tfb_refcnt, 0);
blk->tfb_id = atomic_fetchadd_int(&next_tcp_stack_id, 1);
for (i = 0; i < *num_names; i++) {
n = malloc(sizeof(struct tcp_function), M_TCPFUNCTIONS, wait);
if (n == NULL) {
error = ENOMEM;
goto cleanup;
}
n->tf_fb = blk;
(void)strlcpy(fs.function_set_name, names[i],
sizeof(fs.function_set_name));
rw_wlock(&tcp_function_lock);
if (find_tcp_functions_locked(&fs) != NULL) {
/* Duplicate name space not allowed */
rw_wunlock(&tcp_function_lock);
free(n, M_TCPFUNCTIONS);
error = EALREADY;
goto cleanup;
}
(void)strlcpy(n->tf_name, names[i], sizeof(n->tf_name));
TAILQ_INSERT_TAIL(&t_functions, n, tf_next);
tcp_fb_cnt++;
rw_wunlock(&tcp_function_lock);
}
return(0);
cleanup:
/*
* Deregister the names we just added. Because registration failed
* for names[i], we don't need to deregister that name.
*/
*num_names = i;
rw_wlock(&tcp_function_lock);
while (--i >= 0) {
TAILQ_FOREACH(n, &t_functions, tf_next) {
if (!strncmp(n->tf_name, names[i],
TCP_FUNCTION_NAME_LEN_MAX)) {
TAILQ_REMOVE(&t_functions, n, tf_next);
tcp_fb_cnt--;
n->tf_fb = NULL;
free(n, M_TCPFUNCTIONS);
break;
}
}
}
rw_wunlock(&tcp_function_lock);
return (error);
}
/*
* Register a TCP function block using the name provided in the name
* argument.
*
* Returns 0 on success, or an error code on failure.
*/
int
register_tcp_functions_as_name(struct tcp_function_block *blk, const char *name,
int wait)
{
const char *name_list[1];
int num_names, rv;
num_names = 1;
if (name != NULL)
name_list[0] = name;
else
name_list[0] = blk->tfb_tcp_block_name;
rv = register_tcp_functions_as_names(blk, wait, name_list, &num_names);
return (rv);
}
/*
* Register a TCP function block using the name defined in
* blk->tfb_tcp_block_name.
*
* Returns 0 on success, or an error code on failure.
*/
int
register_tcp_functions(struct tcp_function_block *blk, int wait)
{
return (register_tcp_functions_as_name(blk, NULL, wait));
}
/*
* Deregister all names associated with a function block. This
* functionally removes the function block from use within the system.
*
* When called with a true quiesce argument, mark the function block
* as being removed so no more stacks will use it and determine
* whether the removal would succeed.
*
* When called with a false quiesce argument, actually attempt the
* removal.
*
* When called with a force argument, attempt to switch all TCBs to
* use the default stack instead of returning EBUSY.
*
* Returns 0 on success (or if the removal would succeed, or an error
* code on failure.
*/
int
deregister_tcp_functions(struct tcp_function_block *blk, bool quiesce,
bool force)
{
struct tcp_function *f;
if (blk == &tcp_def_funcblk) {
/* You can't un-register the default */
return (EPERM);
}
rw_wlock(&tcp_function_lock);
if (blk == tcp_func_set_ptr) {
/* You can't free the current default */
rw_wunlock(&tcp_function_lock);
return (EBUSY);
}
/* Mark the block so no more stacks can use it. */
blk->tfb_flags |= TCP_FUNC_BEING_REMOVED;
/*
* If TCBs are still attached to the stack, attempt to switch them
* to the default stack.
*/
if (force && blk->tfb_refcnt) {
struct inpcb *inp;
struct tcpcb *tp;
VNET_ITERATOR_DECL(vnet_iter);
rw_wunlock(&tcp_function_lock);
VNET_LIST_RLOCK();
VNET_FOREACH(vnet_iter) {
CURVNET_SET(vnet_iter);
INP_INFO_WLOCK(&V_tcbinfo);
CK_LIST_FOREACH(inp, V_tcbinfo.ipi_listhead, inp_list) {
INP_WLOCK(inp);
if (inp->inp_flags & INP_TIMEWAIT) {
INP_WUNLOCK(inp);
continue;
}
tp = intotcpcb(inp);
if (tp == NULL || tp->t_fb != blk) {
INP_WUNLOCK(inp);
continue;
}
tcp_switch_back_to_default(tp);
INP_WUNLOCK(inp);
}
INP_INFO_WUNLOCK(&V_tcbinfo);
CURVNET_RESTORE();
}
VNET_LIST_RUNLOCK();
rw_wlock(&tcp_function_lock);
}
if (blk->tfb_refcnt) {
/* TCBs still attached. */
rw_wunlock(&tcp_function_lock);
return (EBUSY);
}
if (quiesce) {
/* Skip removal. */
rw_wunlock(&tcp_function_lock);
return (0);
}
/* Remove any function names that map to this function block. */
while (find_tcp_fb_locked(blk, &f) != NULL) {
TAILQ_REMOVE(&t_functions, f, tf_next);
tcp_fb_cnt--;
f->tf_fb = NULL;
free(f, M_TCPFUNCTIONS);
}
rw_wunlock(&tcp_function_lock);
return (0);
}
void
tcp_init(void)
{
const char *tcbhash_tuneable;
int hashsize;
tcbhash_tuneable = "net.inet.tcp.tcbhashsize";
#ifdef TCP_HHOOK
if (hhook_head_register(HHOOK_TYPE_TCP, HHOOK_TCP_EST_IN,
&V_tcp_hhh[HHOOK_TCP_EST_IN], HHOOK_NOWAIT|HHOOK_HEADISINVNET) != 0)
printf("%s: WARNING: unable to register helper hook\n", __func__);
if (hhook_head_register(HHOOK_TYPE_TCP, HHOOK_TCP_EST_OUT,
&V_tcp_hhh[HHOOK_TCP_EST_OUT], HHOOK_NOWAIT|HHOOK_HEADISINVNET) != 0)
printf("%s: WARNING: unable to register helper hook\n", __func__);
#endif
#ifdef STATS
if (tcp_stats_init())
printf("%s: WARNING: unable to initialise TCP stats\n",
__func__);
#endif
hashsize = TCBHASHSIZE;
TUNABLE_INT_FETCH(tcbhash_tuneable, &hashsize);
if (hashsize == 0) {
/*
* Auto tune the hash size based on maxsockets.
* A perfect hash would have a 1:1 mapping
* (hashsize = maxsockets) however it's been
* suggested that O(2) average is better.
*/
hashsize = maketcp_hashsize(maxsockets / 4);
/*
* Our historical default is 512,
* do not autotune lower than this.
*/
if (hashsize < 512)
hashsize = 512;
if (bootverbose && IS_DEFAULT_VNET(curvnet))
printf("%s: %s auto tuned to %d\n", __func__,
tcbhash_tuneable, hashsize);
}
/*
* We require a hashsize to be a power of two.
* Previously if it was not a power of two we would just reset it
* back to 512, which could be a nasty surprise if you did not notice
* the error message.
* Instead what we do is clip it to the closest power of two lower
* than the specified hash value.
*/
if (!powerof2(hashsize)) {
int oldhashsize = hashsize;
hashsize = maketcp_hashsize(hashsize);
/* prevent absurdly low value */
if (hashsize < 16)
hashsize = 16;
printf("%s: WARNING: TCB hash size not a power of 2, "
"clipped from %d to %d.\n", __func__, oldhashsize,
hashsize);
}
in_pcbinfo_init(&V_tcbinfo, "tcp", &V_tcb, hashsize, hashsize,
"tcp_inpcb", tcp_inpcb_init, IPI_HASHFIELDS_4TUPLE);
/*
* These have to be type stable for the benefit of the timers.
*/
V_tcpcb_zone = uma_zcreate("tcpcb", sizeof(struct tcpcb_mem),
NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, 0);
uma_zone_set_max(V_tcpcb_zone, maxsockets);
uma_zone_set_warning(V_tcpcb_zone, "kern.ipc.maxsockets limit reached");
tcp_tw_init();
syncache_init();
tcp_hc_init();
TUNABLE_INT_FETCH("net.inet.tcp.sack.enable", &V_tcp_do_sack);
V_sack_hole_zone = uma_zcreate("sackhole", sizeof(struct sackhole),
NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, 0);
tcp_fastopen_init();
/* Skip initialization of globals for non-default instances. */
if (!IS_DEFAULT_VNET(curvnet))
return;
tcp_reass_global_init();
/* XXX virtualize those bellow? */
tcp_delacktime = TCPTV_DELACK;
tcp_keepinit = TCPTV_KEEP_INIT;
tcp_keepidle = TCPTV_KEEP_IDLE;
tcp_keepintvl = TCPTV_KEEPINTVL;
tcp_maxpersistidle = TCPTV_KEEP_IDLE;
tcp_msl = TCPTV_MSL;
tcp_rexmit_initial = TCPTV_RTOBASE;
if (tcp_rexmit_initial < 1)
tcp_rexmit_initial = 1;
tcp_rexmit_min = TCPTV_MIN;
if (tcp_rexmit_min < 1)
tcp_rexmit_min = 1;
tcp_persmin = TCPTV_PERSMIN;
tcp_persmax = TCPTV_PERSMAX;
tcp_rexmit_slop = TCPTV_CPU_VAR;
tcp_finwait2_timeout = TCPTV_FINWAIT2_TIMEOUT;
tcp_tcbhashsize = hashsize;
/* Setup the tcp function block list */
TAILQ_INIT(&t_functions);
rw_init(&tcp_function_lock, "tcp_func_lock");
register_tcp_functions(&tcp_def_funcblk, M_WAITOK);
#ifdef TCP_BLACKBOX
/* Initialize the TCP logging data. */
tcp_log_init();
#endif
arc4rand(&V_ts_offset_secret, sizeof(V_ts_offset_secret), 0);
if (tcp_soreceive_stream) {
#ifdef INET
tcp_usrreqs.pru_soreceive = soreceive_stream;
#endif
#ifdef INET6
tcp6_usrreqs.pru_soreceive = soreceive_stream;
#endif /* INET6 */
}
#ifdef INET6
#define TCP_MINPROTOHDR (sizeof(struct ip6_hdr) + sizeof(struct tcphdr))
#else /* INET6 */
#define TCP_MINPROTOHDR (sizeof(struct tcpiphdr))
#endif /* INET6 */
if (max_protohdr < TCP_MINPROTOHDR)
max_protohdr = TCP_MINPROTOHDR;
if (max_linkhdr + TCP_MINPROTOHDR > MHLEN)
panic("tcp_init");
#undef TCP_MINPROTOHDR
ISN_LOCK_INIT();
EVENTHANDLER_REGISTER(shutdown_pre_sync, tcp_fini, NULL,
SHUTDOWN_PRI_DEFAULT);
EVENTHANDLER_REGISTER(maxsockets_change, tcp_zone_change, NULL,
EVENTHANDLER_PRI_ANY);
tcp_inp_lro_direct_queue = counter_u64_alloc(M_WAITOK);
tcp_inp_lro_wokeup_queue = counter_u64_alloc(M_WAITOK);
tcp_inp_lro_compressed = counter_u64_alloc(M_WAITOK);
tcp_inp_lro_single_push = counter_u64_alloc(M_WAITOK);
tcp_inp_lro_locks_taken = counter_u64_alloc(M_WAITOK);
tcp_inp_lro_sack_wake = counter_u64_alloc(M_WAITOK);
#ifdef TCPPCAP
tcp_pcap_init();
#endif
}
#ifdef VIMAGE
static void
tcp_destroy(void *unused __unused)
{
int n;
#ifdef TCP_HHOOK
int error;
#endif
/*
* All our processes are gone, all our sockets should be cleaned
* up, which means, we should be past the tcp_discardcb() calls.
* Sleep to let all tcpcb timers really disappear and cleanup.
*/
for (;;) {
INP_LIST_RLOCK(&V_tcbinfo);
n = V_tcbinfo.ipi_count;
INP_LIST_RUNLOCK(&V_tcbinfo);
if (n == 0)
break;
pause("tcpdes", hz / 10);
}
tcp_hc_destroy();
syncache_destroy();
tcp_tw_destroy();
in_pcbinfo_destroy(&V_tcbinfo);
/* tcp_discardcb() clears the sack_holes up. */
uma_zdestroy(V_sack_hole_zone);
uma_zdestroy(V_tcpcb_zone);
/*
* Cannot free the zone until all tcpcbs are released as we attach
* the allocations to them.
*/
tcp_fastopen_destroy();
#ifdef TCP_HHOOK
error = hhook_head_deregister(V_tcp_hhh[HHOOK_TCP_EST_IN]);
if (error != 0) {
printf("%s: WARNING: unable to deregister helper hook "
"type=%d, id=%d: error %d returned\n", __func__,
HHOOK_TYPE_TCP, HHOOK_TCP_EST_IN, error);
}
error = hhook_head_deregister(V_tcp_hhh[HHOOK_TCP_EST_OUT]);
if (error != 0) {
printf("%s: WARNING: unable to deregister helper hook "
"type=%d, id=%d: error %d returned\n", __func__,
HHOOK_TYPE_TCP, HHOOK_TCP_EST_OUT, error);
}
#endif
}
VNET_SYSUNINIT(tcp, SI_SUB_PROTO_DOMAIN, SI_ORDER_FOURTH, tcp_destroy, NULL);
#endif
void
tcp_fini(void *xtp)
{
}
/*
* Fill in the IP and TCP headers for an outgoing packet, given the tcpcb.
* tcp_template used to store this data in mbufs, but we now recopy it out
* of the tcpcb each time to conserve mbufs.
*/
void
tcpip_fillheaders(struct inpcb *inp, void *ip_ptr, void *tcp_ptr)
{
struct tcphdr *th = (struct tcphdr *)tcp_ptr;
INP_WLOCK_ASSERT(inp);
#ifdef INET6
if ((inp->inp_vflag & INP_IPV6) != 0) {
struct ip6_hdr *ip6;
ip6 = (struct ip6_hdr *)ip_ptr;
ip6->ip6_flow = (ip6->ip6_flow & ~IPV6_FLOWINFO_MASK) |
(inp->inp_flow & IPV6_FLOWINFO_MASK);
ip6->ip6_vfc = (ip6->ip6_vfc & ~IPV6_VERSION_MASK) |
(IPV6_VERSION & IPV6_VERSION_MASK);
ip6->ip6_nxt = IPPROTO_TCP;
ip6->ip6_plen = htons(sizeof(struct tcphdr));
ip6->ip6_src = inp->in6p_laddr;
ip6->ip6_dst = inp->in6p_faddr;
}
#endif /* INET6 */
#if defined(INET6) && defined(INET)
else
#endif
#ifdef INET
{
struct ip *ip;
ip = (struct ip *)ip_ptr;
ip->ip_v = IPVERSION;
ip->ip_hl = 5;
ip->ip_tos = inp->inp_ip_tos;
ip->ip_len = 0;
ip->ip_id = 0;
ip->ip_off = 0;
ip->ip_ttl = inp->inp_ip_ttl;
ip->ip_sum = 0;
ip->ip_p = IPPROTO_TCP;
ip->ip_src = inp->inp_laddr;
ip->ip_dst = inp->inp_faddr;
}
#endif /* INET */
th->th_sport = inp->inp_lport;
th->th_dport = inp->inp_fport;
th->th_seq = 0;
th->th_ack = 0;
th->th_x2 = 0;
th->th_off = 5;
th->th_flags = 0;
th->th_win = 0;
th->th_urp = 0;
th->th_sum = 0; /* in_pseudo() is called later for ipv4 */
}
/*
* Create template to be used to send tcp packets on a connection.
* Allocates an mbuf and fills in a skeletal tcp/ip header. The only
* use for this function is in keepalives, which use tcp_respond.
*/
struct tcptemp *
tcpip_maketemplate(struct inpcb *inp)
{
struct tcptemp *t;
t = malloc(sizeof(*t), M_TEMP, M_NOWAIT);
if (t == NULL)
return (NULL);
tcpip_fillheaders(inp, (void *)&t->tt_ipgen, (void *)&t->tt_t);
return (t);
}
/*
* Send a single message to the TCP at address specified by
* the given TCP/IP header. If m == NULL, then we make a copy
* of the tcpiphdr at th and send directly to the addressed host.
* This is used to force keep alive messages out using the TCP
* template for a connection. If flags are given then we send
* a message back to the TCP which originated the segment th,
* and discard the mbuf containing it and any other attached mbufs.
*
* In any case the ack and sequence number of the transmitted
* segment are as specified by the parameters.
*
* NOTE: If m != NULL, then th must point to *inside* the mbuf.
*/
void
tcp_respond(struct tcpcb *tp, void *ipgen, struct tcphdr *th, struct mbuf *m,
tcp_seq ack, tcp_seq seq, int flags)
{
struct tcpopt to;
struct inpcb *inp;
struct ip *ip;
struct mbuf *optm;
struct tcphdr *nth;
u_char *optp;
#ifdef INET6
struct ip6_hdr *ip6;
int isipv6;
#endif /* INET6 */
int optlen, tlen, win;
bool incl_opts;
KASSERT(tp != NULL || m != NULL, ("tcp_respond: tp and m both NULL"));
NET_EPOCH_ASSERT();
#ifdef INET6
isipv6 = ((struct ip *)ipgen)->ip_v == (IPV6_VERSION >> 4);
ip6 = ipgen;
#endif /* INET6 */
ip = ipgen;
if (tp != NULL) {
inp = tp->t_inpcb;
KASSERT(inp != NULL, ("tcp control block w/o inpcb"));
INP_WLOCK_ASSERT(inp);
} else
inp = NULL;
incl_opts = false;
win = 0;
if (tp != NULL) {
if (!(flags & TH_RST)) {
win = sbspace(&inp->inp_socket->so_rcv);
if (win > TCP_MAXWIN << tp->rcv_scale)
win = TCP_MAXWIN << tp->rcv_scale;
}
if ((tp->t_flags & TF_NOOPT) == 0)
incl_opts = true;
}
if (m == NULL) {
m = m_gethdr(M_NOWAIT, MT_DATA);
if (m == NULL)
return;
m->m_data += max_linkhdr;
#ifdef INET6
if (isipv6) {
bcopy((caddr_t)ip6, mtod(m, caddr_t),
sizeof(struct ip6_hdr));
ip6 = mtod(m, struct ip6_hdr *);
nth = (struct tcphdr *)(ip6 + 1);
} else
#endif /* INET6 */
{
bcopy((caddr_t)ip, mtod(m, caddr_t), sizeof(struct ip));
ip = mtod(m, struct ip *);
nth = (struct tcphdr *)(ip + 1);
}
bcopy((caddr_t)th, (caddr_t)nth, sizeof(struct tcphdr));
flags = TH_ACK;
} else if (!M_WRITABLE(m)) {
struct mbuf *n;
/* Can't reuse 'm', allocate a new mbuf. */
n = m_gethdr(M_NOWAIT, MT_DATA);
if (n == NULL) {
m_freem(m);
return;
}
if (!m_dup_pkthdr(n, m, M_NOWAIT)) {
m_freem(m);
m_freem(n);
return;
}
n->m_data += max_linkhdr;
/* m_len is set later */
#define xchg(a,b,type) { type t; t=a; a=b; b=t; }
#ifdef INET6
if (isipv6) {
bcopy((caddr_t)ip6, mtod(n, caddr_t),
sizeof(struct ip6_hdr));
ip6 = mtod(n, struct ip6_hdr *);
xchg(ip6->ip6_dst, ip6->ip6_src, struct in6_addr);
nth = (struct tcphdr *)(ip6 + 1);
} else
#endif /* INET6 */
{
bcopy((caddr_t)ip, mtod(n, caddr_t), sizeof(struct ip));
ip = mtod(n, struct ip *);
xchg(ip->ip_dst.s_addr, ip->ip_src.s_addr, uint32_t);
nth = (struct tcphdr *)(ip + 1);
}
bcopy((caddr_t)th, (caddr_t)nth, sizeof(struct tcphdr));
xchg(nth->th_dport, nth->th_sport, uint16_t);
th = nth;
m_freem(m);
m = n;
} else {
/*
* reuse the mbuf.
* XXX MRT We inherit the FIB, which is lucky.
*/
m_freem(m->m_next);
m->m_next = NULL;
m->m_data = (caddr_t)ipgen;
/* m_len is set later */
#ifdef INET6
if (isipv6) {
xchg(ip6->ip6_dst, ip6->ip6_src, struct in6_addr);
nth = (struct tcphdr *)(ip6 + 1);
} else
#endif /* INET6 */
{
xchg(ip->ip_dst.s_addr, ip->ip_src.s_addr, uint32_t);
nth = (struct tcphdr *)(ip + 1);
}
if (th != nth) {
/*
* this is usually a case when an extension header
* exists between the IPv6 header and the
* TCP header.
*/
nth->th_sport = th->th_sport;
nth->th_dport = th->th_dport;
}
xchg(nth->th_dport, nth->th_sport, uint16_t);
#undef xchg
}
tlen = 0;
#ifdef INET6
if (isipv6)
tlen = sizeof (struct ip6_hdr) + sizeof (struct tcphdr);
#endif
#if defined(INET) && defined(INET6)
else
#endif
#ifdef INET
tlen = sizeof (struct tcpiphdr);
#endif
#ifdef INVARIANTS
m->m_len = 0;
KASSERT(M_TRAILINGSPACE(m) >= tlen,
("Not enough trailing space for message (m=%p, need=%d, have=%ld)",
m, tlen, (long)M_TRAILINGSPACE(m)));
#endif
m->m_len = tlen;
to.to_flags = 0;
if (incl_opts) {
/* Make sure we have room. */
if (M_TRAILINGSPACE(m) < TCP_MAXOLEN) {
m->m_next = m_get(M_NOWAIT, MT_DATA);
if (m->m_next) {
optp = mtod(m->m_next, u_char *);
optm = m->m_next;
} else
incl_opts = false;
} else {
optp = (u_char *) (nth + 1);
optm = m;
}
}
if (incl_opts) {
/* Timestamps. */
if (tp->t_flags & TF_RCVD_TSTMP) {
to.to_tsval = tcp_ts_getticks() + tp->ts_offset;
to.to_tsecr = tp->ts_recent;
to.to_flags |= TOF_TS;
}
#if defined(IPSEC_SUPPORT) || defined(TCP_SIGNATURE)
/* TCP-MD5 (RFC2385). */
if (tp->t_flags & TF_SIGNATURE)
to.to_flags |= TOF_SIGNATURE;
#endif
/* Add the options. */
tlen += optlen = tcp_addoptions(&to, optp);
/* Update m_len in the correct mbuf. */
optm->m_len += optlen;
} else
optlen = 0;
#ifdef INET6
if (isipv6) {
ip6->ip6_flow = 0;
ip6->ip6_vfc = IPV6_VERSION;
ip6->ip6_nxt = IPPROTO_TCP;
ip6->ip6_plen = htons(tlen - sizeof(*ip6));
}
#endif
#if defined(INET) && defined(INET6)
else
#endif
#ifdef INET
{
ip->ip_len = htons(tlen);
ip->ip_ttl = V_ip_defttl;
if (V_path_mtu_discovery)
ip->ip_off |= htons(IP_DF);
}
#endif
m->m_pkthdr.len = tlen;
m->m_pkthdr.rcvif = NULL;
#ifdef MAC
if (inp != NULL) {
/*
* Packet is associated with a socket, so allow the
* label of the response to reflect the socket label.
*/
INP_WLOCK_ASSERT(inp);
mac_inpcb_create_mbuf(inp, m);
} else {
/*
* Packet is not associated with a socket, so possibly
* update the label in place.
*/
mac_netinet_tcp_reply(m);
}
#endif
nth->th_seq = htonl(seq);
nth->th_ack = htonl(ack);
nth->th_x2 = 0;
nth->th_off = (sizeof (struct tcphdr) + optlen) >> 2;
nth->th_flags = flags;
if (tp != NULL)
nth->th_win = htons((u_short) (win >> tp->rcv_scale));
else
nth->th_win = htons((u_short)win);
nth->th_urp = 0;
#if defined(IPSEC_SUPPORT) || defined(TCP_SIGNATURE)
if (to.to_flags & TOF_SIGNATURE) {
if (!TCPMD5_ENABLED() ||
TCPMD5_OUTPUT(m, nth, to.to_signature) != 0) {
m_freem(m);
return;
}
}
#endif
m->m_pkthdr.csum_data = offsetof(struct tcphdr, th_sum);
#ifdef INET6
if (isipv6) {
m->m_pkthdr.csum_flags = CSUM_TCP_IPV6;
nth->th_sum = in6_cksum_pseudo(ip6,
tlen - sizeof(struct ip6_hdr), IPPROTO_TCP, 0);
ip6->ip6_hlim = in6_selecthlim(tp != NULL ? tp->t_inpcb :
NULL, NULL);
}
#endif /* INET6 */
#if defined(INET6) && defined(INET)
else
#endif
#ifdef INET
{
m->m_pkthdr.csum_flags = CSUM_TCP;
nth->th_sum = in_pseudo(ip->ip_src.s_addr, ip->ip_dst.s_addr,
htons((u_short)(tlen - sizeof(struct ip) + ip->ip_p)));
}
#endif /* INET */
#ifdef TCPDEBUG
if (tp == NULL || (inp->inp_socket->so_options & SO_DEBUG))
tcp_trace(TA_OUTPUT, 0, tp, mtod(m, void *), th, 0);
#endif
TCP_PROBE3(debug__output, tp, th, m);
if (flags & TH_RST)
TCP_PROBE5(accept__refused, NULL, NULL, m, tp, nth);
#ifdef INET6
if (isipv6) {
TCP_PROBE5(send, NULL, tp, ip6, tp, nth);
(void)ip6_output(m, NULL, NULL, 0, NULL, NULL, inp);
}
#endif /* INET6 */
#if defined(INET) && defined(INET6)
else
#endif
#ifdef INET
{
TCP_PROBE5(send, NULL, tp, ip, tp, nth);
(void)ip_output(m, NULL, NULL, 0, NULL, inp);
}
#endif
}
/*
* Create a new TCP control block, making an
* empty reassembly queue and hooking it to the argument
* protocol control block. The `inp' parameter must have
* come from the zone allocator set up in tcp_init().
*/
struct tcpcb *
tcp_newtcpcb(struct inpcb *inp)
{
struct tcpcb_mem *tm;
struct tcpcb *tp;
#ifdef INET6
int isipv6 = (inp->inp_vflag & INP_IPV6) != 0;
#endif /* INET6 */
tm = uma_zalloc(V_tcpcb_zone, M_NOWAIT | M_ZERO);
if (tm == NULL)
return (NULL);
tp = &tm->tcb;
/* Initialise cc_var struct for this tcpcb. */
tp->ccv = &tm->ccv;
tp->ccv->type = IPPROTO_TCP;
tp->ccv->ccvc.tcp = tp;
rw_rlock(&tcp_function_lock);
tp->t_fb = tcp_func_set_ptr;
refcount_acquire(&tp->t_fb->tfb_refcnt);
rw_runlock(&tcp_function_lock);
/*
* Use the current system default CC algorithm.
*/
CC_LIST_RLOCK();
KASSERT(!STAILQ_EMPTY(&cc_list), ("cc_list is empty!"));
CC_ALGO(tp) = CC_DEFAULT();
CC_LIST_RUNLOCK();
/*
* The tcpcb will hold a reference on its inpcb until tcp_discardcb()
* is called.
*/
in_pcbref(inp); /* Reference for tcpcb */
tp->t_inpcb = inp;
if (CC_ALGO(tp)->cb_init != NULL)
if (CC_ALGO(tp)->cb_init(tp->ccv) > 0) {
if (tp->t_fb->tfb_tcp_fb_fini)
(*tp->t_fb->tfb_tcp_fb_fini)(tp, 1);
in_pcbrele_wlocked(inp);
refcount_release(&tp->t_fb->tfb_refcnt);
uma_zfree(V_tcpcb_zone, tm);
return (NULL);
}
#ifdef TCP_HHOOK
tp->osd = &tm->osd;
if (khelp_init_osd(HELPER_CLASS_TCP, tp->osd)) {
if (tp->t_fb->tfb_tcp_fb_fini)
(*tp->t_fb->tfb_tcp_fb_fini)(tp, 1);
in_pcbrele_wlocked(inp);
refcount_release(&tp->t_fb->tfb_refcnt);
uma_zfree(V_tcpcb_zone, tm);
return (NULL);
}
#endif
#ifdef VIMAGE
tp->t_vnet = inp->inp_vnet;
#endif
tp->t_timers = &tm->tt;
TAILQ_INIT(&tp->t_segq);
tp->t_maxseg =
#ifdef INET6
isipv6 ? V_tcp_v6mssdflt :
#endif /* INET6 */
V_tcp_mssdflt;
/* Set up our timeouts. */
callout_init(&tp->t_timers->tt_rexmt, 1);
callout_init(&tp->t_timers->tt_persist, 1);
callout_init(&tp->t_timers->tt_keep, 1);
callout_init(&tp->t_timers->tt_2msl, 1);
callout_init(&tp->t_timers->tt_delack, 1);
if (V_tcp_do_rfc1323)
tp->t_flags = (TF_REQ_SCALE|TF_REQ_TSTMP);
if (V_tcp_do_sack)
tp->t_flags |= TF_SACK_PERMIT;
TAILQ_INIT(&tp->snd_holes);
/*
* Init srtt to TCPTV_SRTTBASE (0), so we can tell that we have no
* rtt estimate. Set rttvar so that srtt + 4 * rttvar gives
* reasonable initial retransmit time.
*/
tp->t_srtt = TCPTV_SRTTBASE;
tp->t_rttvar = ((tcp_rexmit_initial - TCPTV_SRTTBASE) << TCP_RTTVAR_SHIFT) / 4;
tp->t_rttmin = tcp_rexmit_min;
tp->t_rxtcur = tcp_rexmit_initial;
tp->snd_cwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT;
tp->snd_ssthresh = TCP_MAXWIN << TCP_MAX_WINSHIFT;
tp->t_rcvtime = ticks;
/*
* IPv4 TTL initialization is necessary for an IPv6 socket as well,
* because the socket may be bound to an IPv6 wildcard address,
* which may match an IPv4-mapped IPv6 address.
*/
inp->inp_ip_ttl = V_ip_defttl;
inp->inp_ppcb = tp;
#ifdef TCPPCAP
/*
* Init the TCP PCAP queues.
*/
tcp_pcap_tcpcb_init(tp);
#endif
#ifdef TCP_BLACKBOX
/* Initialize the per-TCPCB log data. */
tcp_log_tcpcbinit(tp);
#endif
tp->t_pacing_rate = -1;
if (tp->t_fb->tfb_tcp_fb_init) {
if ((*tp->t_fb->tfb_tcp_fb_init)(tp)) {
refcount_release(&tp->t_fb->tfb_refcnt);
in_pcbrele_wlocked(inp);
uma_zfree(V_tcpcb_zone, tm);
return (NULL);
}
}
#ifdef STATS
if (V_tcp_perconn_stats_enable == 1)
tp->t_stats = stats_blob_alloc(V_tcp_perconn_stats_dflt_tpl, 0);
#endif
return (tp); /* XXX */
}
/*
* Switch the congestion control algorithm back to NewReno for any active
* control blocks using an algorithm which is about to go away.
* This ensures the CC framework can allow the unload to proceed without leaving
* any dangling pointers which would trigger a panic.
* Returning non-zero would inform the CC framework that something went wrong
* and it would be unsafe to allow the unload to proceed. However, there is no
* way for this to occur with this implementation so we always return zero.
*/
int
tcp_ccalgounload(struct cc_algo *unload_algo)
{
struct cc_algo *tmpalgo;
struct inpcb *inp;
struct tcpcb *tp;
VNET_ITERATOR_DECL(vnet_iter);
/*
* Check all active control blocks across all network stacks and change
* any that are using "unload_algo" back to NewReno. If "unload_algo"
* requires cleanup code to be run, call it.
*/
VNET_LIST_RLOCK();
VNET_FOREACH(vnet_iter) {
CURVNET_SET(vnet_iter);
INP_INFO_WLOCK(&V_tcbinfo);
/*
* New connections already part way through being initialised
* with the CC algo we're removing will not race with this code
* because the INP_INFO_WLOCK is held during initialisation. We
* therefore don't enter the loop below until the connection
* list has stabilised.
*/
CK_LIST_FOREACH(inp, &V_tcb, inp_list) {
INP_WLOCK(inp);
/* Important to skip tcptw structs. */
if (!(inp->inp_flags & INP_TIMEWAIT) &&
(tp = intotcpcb(inp)) != NULL) {
/*
* By holding INP_WLOCK here, we are assured
* that the connection is not currently
* executing inside the CC module's functions
* i.e. it is safe to make the switch back to
* NewReno.
*/
if (CC_ALGO(tp) == unload_algo) {
tmpalgo = CC_ALGO(tp);
if (tmpalgo->cb_destroy != NULL)
tmpalgo->cb_destroy(tp->ccv);
CC_DATA(tp) = NULL;
/*
* NewReno may allocate memory on
* demand for certain stateful
* configuration as needed, but is
* coded to never fail on memory
* allocation failure so it is a safe
* fallback.
*/
CC_ALGO(tp) = &newreno_cc_algo;
}
}
INP_WUNLOCK(inp);
}
INP_INFO_WUNLOCK(&V_tcbinfo);
CURVNET_RESTORE();
}
VNET_LIST_RUNLOCK();
return (0);
}
/*
* Drop a TCP connection, reporting
* the specified error. If connection is synchronized,
* then send a RST to peer.
*/
struct tcpcb *
tcp_drop(struct tcpcb *tp, int errno)
{
struct socket *so = tp->t_inpcb->inp_socket;
NET_EPOCH_ASSERT();
INP_INFO_LOCK_ASSERT(&V_tcbinfo);
INP_WLOCK_ASSERT(tp->t_inpcb);
if (TCPS_HAVERCVDSYN(tp->t_state)) {
tcp_state_change(tp, TCPS_CLOSED);
(void) tp->t_fb->tfb_tcp_output(tp);
TCPSTAT_INC(tcps_drops);
} else
TCPSTAT_INC(tcps_conndrops);
if (errno == ETIMEDOUT && tp->t_softerror)
errno = tp->t_softerror;
so->so_error = errno;
return (tcp_close(tp));
}
void
tcp_discardcb(struct tcpcb *tp)
{
struct inpcb *inp = tp->t_inpcb;
struct socket *so = inp->inp_socket;
#ifdef INET6
int isipv6 = (inp->inp_vflag & INP_IPV6) != 0;
#endif /* INET6 */
int released __unused;
INP_WLOCK_ASSERT(inp);
/*
* Make sure that all of our timers are stopped before we delete the
* PCB.
*
* If stopping a timer fails, we schedule a discard function in same
* callout, and the last discard function called will take care of
* deleting the tcpcb.
*/
tp->t_timers->tt_draincnt = 0;
tcp_timer_stop(tp, TT_REXMT);
tcp_timer_stop(tp, TT_PERSIST);
tcp_timer_stop(tp, TT_KEEP);
tcp_timer_stop(tp, TT_2MSL);
tcp_timer_stop(tp, TT_DELACK);
if (tp->t_fb->tfb_tcp_timer_stop_all) {
/*
* Call the stop-all function of the methods,
* this function should call the tcp_timer_stop()
* method with each of the function specific timeouts.
* That stop will be called via the tfb_tcp_timer_stop()
* which should use the async drain function of the
* callout system (see tcp_var.h).
*/
tp->t_fb->tfb_tcp_timer_stop_all(tp);
}
/*
* If we got enough samples through the srtt filter,
* save the rtt and rttvar in the routing entry.
* 'Enough' is arbitrarily defined as 4 rtt samples.
* 4 samples is enough for the srtt filter to converge
* to within enough % of the correct value; fewer samples
* and we could save a bogus rtt. The danger is not high
* as tcp quickly recovers from everything.
* XXX: Works very well but needs some more statistics!
*/
if (tp->t_rttupdated >= 4) {
struct hc_metrics_lite metrics;
uint32_t ssthresh;
bzero(&metrics, sizeof(metrics));
/*
* Update the ssthresh always when the conditions below
* are satisfied. This gives us better new start value
* for the congestion avoidance for new connections.
* ssthresh is only set if packet loss occurred on a session.
*
* XXXRW: 'so' may be NULL here, and/or socket buffer may be
* being torn down. Ideally this code would not use 'so'.
*/
ssthresh = tp->snd_ssthresh;
if (ssthresh != 0 && ssthresh < so->so_snd.sb_hiwat / 2) {
/*
* convert the limit from user data bytes to
* packets then to packet data bytes.
*/
ssthresh = (ssthresh + tp->t_maxseg / 2) / tp->t_maxseg;
if (ssthresh < 2)
ssthresh = 2;
ssthresh *= (tp->t_maxseg +
#ifdef INET6
(isipv6 ? sizeof (struct ip6_hdr) +
sizeof (struct tcphdr) :
#endif
sizeof (struct tcpiphdr)
#ifdef INET6
)
#endif
);
} else
ssthresh = 0;
metrics.rmx_ssthresh = ssthresh;
metrics.rmx_rtt = tp->t_srtt;
metrics.rmx_rttvar = tp->t_rttvar;
metrics.rmx_cwnd = tp->snd_cwnd;
metrics.rmx_sendpipe = 0;
metrics.rmx_recvpipe = 0;
tcp_hc_update(&inp->inp_inc, &metrics);
}
/* free the reassembly queue, if any */
tcp_reass_flush(tp);
#ifdef TCP_OFFLOAD
/* Disconnect offload device, if any. */
if (tp->t_flags & TF_TOE)
tcp_offload_detach(tp);
#endif
tcp_free_sackholes(tp);
#ifdef TCPPCAP
/* Free the TCP PCAP queues. */
tcp_pcap_drain(&(tp->t_inpkts));
tcp_pcap_drain(&(tp->t_outpkts));
#endif
/* Allow the CC algorithm to clean up after itself. */
if (CC_ALGO(tp)->cb_destroy != NULL)
CC_ALGO(tp)->cb_destroy(tp->ccv);
CC_DATA(tp) = NULL;
#ifdef TCP_HHOOK
khelp_destroy_osd(tp->osd);
#endif
#ifdef STATS
stats_blob_destroy(tp->t_stats);
#endif
CC_ALGO(tp) = NULL;
inp->inp_ppcb = NULL;
if (tp->t_timers->tt_draincnt == 0) {
/* We own the last reference on tcpcb, let's free it. */
#ifdef TCP_BLACKBOX
tcp_log_tcpcbfini(tp);
#endif
TCPSTATES_DEC(tp->t_state);
if (tp->t_fb->tfb_tcp_fb_fini)
(*tp->t_fb->tfb_tcp_fb_fini)(tp, 1);
refcount_release(&tp->t_fb->tfb_refcnt);
tp->t_inpcb = NULL;
uma_zfree(V_tcpcb_zone, tp);
released = in_pcbrele_wlocked(inp);
KASSERT(!released, ("%s: inp %p should not have been released "
"here", __func__, inp));
}
}
void
tcp_timer_discard(void *ptp)
{
struct inpcb *inp;
struct tcpcb *tp;
struct epoch_tracker et;
tp = (struct tcpcb *)ptp;
CURVNET_SET(tp->t_vnet);
NET_EPOCH_ENTER(et);
inp = tp->t_inpcb;
KASSERT(inp != NULL, ("%s: tp %p tp->t_inpcb == NULL",
__func__, tp));
INP_WLOCK(inp);
KASSERT((tp->t_timers->tt_flags & TT_STOPPED) != 0,
("%s: tcpcb has to be stopped here", __func__));
tp->t_timers->tt_draincnt--;
if (tp->t_timers->tt_draincnt == 0) {
/* We own the last reference on this tcpcb, let's free it. */
#ifdef TCP_BLACKBOX
tcp_log_tcpcbfini(tp);
#endif
TCPSTATES_DEC(tp->t_state);
if (tp->t_fb->tfb_tcp_fb_fini)
(*tp->t_fb->tfb_tcp_fb_fini)(tp, 1);
refcount_release(&tp->t_fb->tfb_refcnt);
tp->t_inpcb = NULL;
uma_zfree(V_tcpcb_zone, tp);
if (in_pcbrele_wlocked(inp)) {
NET_EPOCH_EXIT(et);
CURVNET_RESTORE();
return;
}
}
INP_WUNLOCK(inp);
NET_EPOCH_EXIT(et);
CURVNET_RESTORE();
}
/*
* Attempt to close a TCP control block, marking it as dropped, and freeing
* the socket if we hold the only reference.
*/
struct tcpcb *
tcp_close(struct tcpcb *tp)
{
struct inpcb *inp = tp->t_inpcb;
struct socket *so;
INP_INFO_LOCK_ASSERT(&V_tcbinfo);
INP_WLOCK_ASSERT(inp);
#ifdef TCP_OFFLOAD
if (tp->t_state == TCPS_LISTEN)
tcp_offload_listen_stop(tp);
#endif
/*
* This releases the TFO pending counter resource for TFO listen
* sockets as well as passively-created TFO sockets that transition
* from SYN_RECEIVED to CLOSED.
*/
if (tp->t_tfo_pending) {
tcp_fastopen_decrement_counter(tp->t_tfo_pending);
tp->t_tfo_pending = NULL;
}
in_pcbdrop(inp);
TCPSTAT_INC(tcps_closed);
if (tp->t_state != TCPS_CLOSED)
tcp_state_change(tp, TCPS_CLOSED);
KASSERT(inp->inp_socket != NULL, ("tcp_close: inp_socket NULL"));
so = inp->inp_socket;
soisdisconnected(so);
if (inp->inp_flags & INP_SOCKREF) {
KASSERT(so->so_state & SS_PROTOREF,
("tcp_close: !SS_PROTOREF"));
inp->inp_flags &= ~INP_SOCKREF;
INP_WUNLOCK(inp);
SOCK_LOCK(so);
so->so_state &= ~SS_PROTOREF;
sofree(so);
return (NULL);
}
return (tp);
}
void
tcp_drain(void)
{
VNET_ITERATOR_DECL(vnet_iter);
if (!do_tcpdrain)
return;
VNET_LIST_RLOCK_NOSLEEP();
VNET_FOREACH(vnet_iter) {
CURVNET_SET(vnet_iter);
struct inpcb *inpb;
struct tcpcb *tcpb;
/*
* Walk the tcpbs, if existing, and flush the reassembly queue,
* if there is one...
* XXX: The "Net/3" implementation doesn't imply that the TCP
* reassembly queue should be flushed, but in a situation
* where we're really low on mbufs, this is potentially
* useful.
*/
INP_INFO_WLOCK(&V_tcbinfo);
CK_LIST_FOREACH(inpb, V_tcbinfo.ipi_listhead, inp_list) {
INP_WLOCK(inpb);
if (inpb->inp_flags & INP_TIMEWAIT) {
INP_WUNLOCK(inpb);
continue;
}
if ((tcpb = intotcpcb(inpb)) != NULL) {
tcp_reass_flush(tcpb);
tcp_clean_sackreport(tcpb);
#ifdef TCP_BLACKBOX
tcp_log_drain(tcpb);
#endif
#ifdef TCPPCAP
if (tcp_pcap_aggressive_free) {
/* Free the TCP PCAP queues. */
tcp_pcap_drain(&(tcpb->t_inpkts));
tcp_pcap_drain(&(tcpb->t_outpkts));
}
#endif
}
INP_WUNLOCK(inpb);
}
INP_INFO_WUNLOCK(&V_tcbinfo);
CURVNET_RESTORE();
}
VNET_LIST_RUNLOCK_NOSLEEP();
}
/*
* Notify a tcp user of an asynchronous error;
* store error as soft error, but wake up user
* (for now, won't do anything until can select for soft error).
*
* Do not wake up user since there currently is no mechanism for
* reporting soft errors (yet - a kqueue filter may be added).
*/
static struct inpcb *
tcp_notify(struct inpcb *inp, int error)
{
struct tcpcb *tp;
INP_INFO_LOCK_ASSERT(&V_tcbinfo);
INP_WLOCK_ASSERT(inp);
if ((inp->inp_flags & INP_TIMEWAIT) ||
(inp->inp_flags & INP_DROPPED))
return (inp);
tp = intotcpcb(inp);
KASSERT(tp != NULL, ("tcp_notify: tp == NULL"));
/*
* Ignore some errors if we are hooked up.
* If connection hasn't completed, has retransmitted several times,
* and receives a second error, give up now. This is better
* than waiting a long time to establish a connection that
* can never complete.
*/
if (tp->t_state == TCPS_ESTABLISHED &&
(error == EHOSTUNREACH || error == ENETUNREACH ||
error == EHOSTDOWN)) {
if (inp->inp_route.ro_nh) {
NH_FREE(inp->inp_route.ro_nh);
inp->inp_route.ro_nh = (struct nhop_object *)NULL;
}
return (inp);
} else if (tp->t_state < TCPS_ESTABLISHED && tp->t_rxtshift > 3 &&
tp->t_softerror) {
tp = tcp_drop(tp, error);
if (tp != NULL)
return (inp);
else
return (NULL);
} else {
tp->t_softerror = error;
return (inp);
}
#if 0
wakeup( &so->so_timeo);
sorwakeup(so);
sowwakeup(so);
#endif
}
static int
tcp_pcblist(SYSCTL_HANDLER_ARGS)
{
struct epoch_tracker et;
struct inpcb *inp;
struct xinpgen xig;
int error;
if (req->newptr != NULL)
return (EPERM);
if (req->oldptr == NULL) {
int n;
n = V_tcbinfo.ipi_count +
counter_u64_fetch(V_tcps_states[TCPS_SYN_RECEIVED]);
n += imax(n / 8, 10);
req->oldidx = 2 * (sizeof xig) + n * sizeof(struct xtcpcb);
return (0);
}
if ((error = sysctl_wire_old_buffer(req, 0)) != 0)
return (error);
bzero(&xig, sizeof(xig));
xig.xig_len = sizeof xig;
xig.xig_count = V_tcbinfo.ipi_count +
counter_u64_fetch(V_tcps_states[TCPS_SYN_RECEIVED]);
xig.xig_gen = V_tcbinfo.ipi_gencnt;
xig.xig_sogen = so_gencnt;
error = SYSCTL_OUT(req, &xig, sizeof xig);
if (error)
return (error);
error = syncache_pcblist(req);
if (error)
return (error);
NET_EPOCH_ENTER(et);
for (inp = CK_LIST_FIRST(V_tcbinfo.ipi_listhead);
inp != NULL;
inp = CK_LIST_NEXT(inp, inp_list)) {
INP_RLOCK(inp);
if (inp->inp_gencnt <= xig.xig_gen) {
int crerr;
/*
* XXX: This use of cr_cansee(), introduced with
* TCP state changes, is not quite right, but for
* now, better than nothing.
*/
if (inp->inp_flags & INP_TIMEWAIT) {
if (intotw(inp) != NULL)
crerr = cr_cansee(req->td->td_ucred,
intotw(inp)->tw_cred);
else
crerr = EINVAL; /* Skip this inp. */
} else
crerr = cr_canseeinpcb(req->td->td_ucred, inp);
if (crerr == 0) {
struct xtcpcb xt;
tcp_inptoxtp(inp, &xt);
INP_RUNLOCK(inp);
error = SYSCTL_OUT(req, &xt, sizeof xt);
if (error)
break;
else
continue;
}
}
INP_RUNLOCK(inp);
}
NET_EPOCH_EXIT(et);
if (!error) {
/*
* Give the user an updated idea of our state.
* If the generation differs from what we told
* her before, she knows that something happened
* while we were processing this request, and it
* might be necessary to retry.
*/
xig.xig_gen = V_tcbinfo.ipi_gencnt;
xig.xig_sogen = so_gencnt;
xig.xig_count = V_tcbinfo.ipi_count +
counter_u64_fetch(V_tcps_states[TCPS_SYN_RECEIVED]);
error = SYSCTL_OUT(req, &xig, sizeof xig);
}
return (error);
}
SYSCTL_PROC(_net_inet_tcp, TCPCTL_PCBLIST, pcblist,
CTLTYPE_OPAQUE | CTLFLAG_RD | CTLFLAG_NEEDGIANT,
NULL, 0, tcp_pcblist, "S,xtcpcb",
"List of active TCP connections");
#ifdef INET
static int
tcp_getcred(SYSCTL_HANDLER_ARGS)
{
struct xucred xuc;
struct sockaddr_in addrs[2];
struct epoch_tracker et;
struct inpcb *inp;
int error;
error = priv_check(req->td, PRIV_NETINET_GETCRED);
if (error)
return (error);
error = SYSCTL_IN(req, addrs, sizeof(addrs));
if (error)
return (error);
NET_EPOCH_ENTER(et);
inp = in_pcblookup(&V_tcbinfo, addrs[1].sin_addr, addrs[1].sin_port,
addrs[0].sin_addr, addrs[0].sin_port, INPLOOKUP_RLOCKPCB, NULL);
NET_EPOCH_EXIT(et);
if (inp != NULL) {
if (inp->inp_socket == NULL)
error = ENOENT;
if (error == 0)
error = cr_canseeinpcb(req->td->td_ucred, inp);
if (error == 0)
cru2x(inp->inp_cred, &xuc);
INP_RUNLOCK(inp);
} else
error = ENOENT;
if (error == 0)
error = SYSCTL_OUT(req, &xuc, sizeof(struct xucred));
return (error);
}
SYSCTL_PROC(_net_inet_tcp, OID_AUTO, getcred,
CTLTYPE_OPAQUE | CTLFLAG_RW | CTLFLAG_PRISON | CTLFLAG_NEEDGIANT,
0, 0, tcp_getcred, "S,xucred",
"Get the xucred of a TCP connection");
#endif /* INET */
#ifdef INET6
static int
tcp6_getcred(SYSCTL_HANDLER_ARGS)
{
struct epoch_tracker et;
struct xucred xuc;
struct sockaddr_in6 addrs[2];
struct inpcb *inp;
int error;
#ifdef INET
int mapped = 0;
#endif
error = priv_check(req->td, PRIV_NETINET_GETCRED);
if (error)
return (error);
error = SYSCTL_IN(req, addrs, sizeof(addrs));
if (error)
return (error);
if ((error = sa6_embedscope(&addrs[0], V_ip6_use_defzone)) != 0 ||
(error = sa6_embedscope(&addrs[1], V_ip6_use_defzone)) != 0) {
return (error);
}
if (IN6_IS_ADDR_V4MAPPED(&addrs[0].sin6_addr)) {
#ifdef INET
if (IN6_IS_ADDR_V4MAPPED(&addrs[1].sin6_addr))
mapped = 1;
else
#endif
return (EINVAL);
}
NET_EPOCH_ENTER(et);
#ifdef INET
if (mapped == 1)
inp = in_pcblookup(&V_tcbinfo,
*(struct in_addr *)&addrs[1].sin6_addr.s6_addr[12],
addrs[1].sin6_port,
*(struct in_addr *)&addrs[0].sin6_addr.s6_addr[12],
addrs[0].sin6_port, INPLOOKUP_RLOCKPCB, NULL);
else
#endif
inp = in6_pcblookup(&V_tcbinfo,
&addrs[1].sin6_addr, addrs[1].sin6_port,
&addrs[0].sin6_addr, addrs[0].sin6_port,
INPLOOKUP_RLOCKPCB, NULL);
NET_EPOCH_EXIT(et);
if (inp != NULL) {
if (inp->inp_socket == NULL)
error = ENOENT;
if (error == 0)
error = cr_canseeinpcb(req->td->td_ucred, inp);
if (error == 0)
cru2x(inp->inp_cred, &xuc);
INP_RUNLOCK(inp);
} else
error = ENOENT;
if (error == 0)
error = SYSCTL_OUT(req, &xuc, sizeof(struct xucred));
return (error);
}
SYSCTL_PROC(_net_inet6_tcp6, OID_AUTO, getcred,
CTLTYPE_OPAQUE | CTLFLAG_RW | CTLFLAG_PRISON | CTLFLAG_NEEDGIANT,
0, 0, tcp6_getcred, "S,xucred",
"Get the xucred of a TCP6 connection");
#endif /* INET6 */
#ifdef INET
void
tcp_ctlinput(int cmd, struct sockaddr *sa, void *vip)
{
struct ip *ip = vip;
struct tcphdr *th;
struct in_addr faddr;
struct inpcb *inp;
struct tcpcb *tp;
struct inpcb *(*notify)(struct inpcb *, int) = tcp_notify;
struct icmp *icp;
struct in_conninfo inc;
tcp_seq icmp_tcp_seq;
int mtu;
faddr = ((struct sockaddr_in *)sa)->sin_addr;
if (sa->sa_family != AF_INET || faddr.s_addr == INADDR_ANY)
return;
if (cmd == PRC_MSGSIZE)
notify = tcp_mtudisc_notify;
else if (V_icmp_may_rst && (cmd == PRC_UNREACH_ADMIN_PROHIB ||
cmd == PRC_UNREACH_PORT || cmd == PRC_UNREACH_PROTOCOL ||
cmd == PRC_TIMXCEED_INTRANS) && ip)
notify = tcp_drop_syn_sent;
/*
* Hostdead is ugly because it goes linearly through all PCBs.
* XXX: We never get this from ICMP, otherwise it makes an
* excellent DoS attack on machines with many connections.
*/
else if (cmd == PRC_HOSTDEAD)
ip = NULL;
else if ((unsigned)cmd >= PRC_NCMDS || inetctlerrmap[cmd] == 0)
return;
if (ip == NULL) {
in_pcbnotifyall(&V_tcbinfo, faddr, inetctlerrmap[cmd], notify);
return;
}
icp = (struct icmp *)((caddr_t)ip - offsetof(struct icmp, icmp_ip));
th = (struct tcphdr *)((caddr_t)ip + (ip->ip_hl << 2));
inp = in_pcblookup(&V_tcbinfo, faddr, th->th_dport, ip->ip_src,
th->th_sport, INPLOOKUP_WLOCKPCB, NULL);
if (inp != NULL && PRC_IS_REDIRECT(cmd)) {
/* signal EHOSTDOWN, as it flushes the cached route */
inp = (*notify)(inp, EHOSTDOWN);
goto out;
}
icmp_tcp_seq = th->th_seq;
if (inp != NULL) {
if (!(inp->inp_flags & INP_TIMEWAIT) &&
!(inp->inp_flags & INP_DROPPED) &&
!(inp->inp_socket == NULL)) {
tp = intotcpcb(inp);
if (SEQ_GEQ(ntohl(icmp_tcp_seq), tp->snd_una) &&
SEQ_LT(ntohl(icmp_tcp_seq), tp->snd_max)) {
if (cmd == PRC_MSGSIZE) {
/*
* MTU discovery:
* If we got a needfrag set the MTU
* in the route to the suggested new
* value (if given) and then notify.
*/
mtu = ntohs(icp->icmp_nextmtu);
/*
* If no alternative MTU was
* proposed, try the next smaller
* one.
*/
if (!mtu)
mtu = ip_next_mtu(
ntohs(ip->ip_len), 1);
if (mtu < V_tcp_minmss +
sizeof(struct tcpiphdr))
mtu = V_tcp_minmss +
sizeof(struct tcpiphdr);
/*
* Only process the offered MTU if it
* is smaller than the current one.
*/
if (mtu < tp->t_maxseg +
sizeof(struct tcpiphdr)) {
bzero(&inc, sizeof(inc));
inc.inc_faddr = faddr;
inc.inc_fibnum =
inp->inp_inc.inc_fibnum;
tcp_hc_updatemtu(&inc, mtu);
tcp_mtudisc(inp, mtu);
}
} else
inp = (*notify)(inp,
inetctlerrmap[cmd]);
}
}
} else {
bzero(&inc, sizeof(inc));
inc.inc_fport = th->th_dport;
inc.inc_lport = th->th_sport;
inc.inc_faddr = faddr;
inc.inc_laddr = ip->ip_src;
syncache_unreach(&inc, icmp_tcp_seq);
}
out:
if (inp != NULL)
INP_WUNLOCK(inp);
}
#endif /* INET */
#ifdef INET6
void
tcp6_ctlinput(int cmd, struct sockaddr *sa, void *d)
{
struct in6_addr *dst;
struct inpcb *(*notify)(struct inpcb *, int) = tcp_notify;
struct ip6_hdr *ip6;
struct mbuf *m;
struct inpcb *inp;
struct tcpcb *tp;
struct icmp6_hdr *icmp6;
struct ip6ctlparam *ip6cp = NULL;
const struct sockaddr_in6 *sa6_src = NULL;
struct in_conninfo inc;
struct tcp_ports {
uint16_t th_sport;
uint16_t th_dport;
} t_ports;
tcp_seq icmp_tcp_seq;
unsigned int mtu;
unsigned int off;
if (sa->sa_family != AF_INET6 ||
sa->sa_len != sizeof(struct sockaddr_in6))
return;
/* if the parameter is from icmp6, decode it. */
if (d != NULL) {
ip6cp = (struct ip6ctlparam *)d;
icmp6 = ip6cp->ip6c_icmp6;
m = ip6cp->ip6c_m;
ip6 = ip6cp->ip6c_ip6;
off = ip6cp->ip6c_off;
sa6_src = ip6cp->ip6c_src;
dst = ip6cp->ip6c_finaldst;
} else {
m = NULL;
ip6 = NULL;
off = 0; /* fool gcc */
sa6_src = &sa6_any;
dst = NULL;
}
if (cmd == PRC_MSGSIZE)
notify = tcp_mtudisc_notify;
else if (V_icmp_may_rst && (cmd == PRC_UNREACH_ADMIN_PROHIB ||
cmd == PRC_UNREACH_PORT || cmd == PRC_UNREACH_PROTOCOL ||
cmd == PRC_TIMXCEED_INTRANS) && ip6 != NULL)
notify = tcp_drop_syn_sent;
/*
* Hostdead is ugly because it goes linearly through all PCBs.
* XXX: We never get this from ICMP, otherwise it makes an
* excellent DoS attack on machines with many connections.
*/
else if (cmd == PRC_HOSTDEAD)
ip6 = NULL;
else if ((unsigned)cmd >= PRC_NCMDS || inet6ctlerrmap[cmd] == 0)
return;
if (ip6 == NULL) {
in6_pcbnotify(&V_tcbinfo, sa, 0,
(const struct sockaddr *)sa6_src,
0, cmd, NULL, notify);
return;
}
/* Check if we can safely get the ports from the tcp hdr */
if (m == NULL ||
(m->m_pkthdr.len <
(int32_t) (off + sizeof(struct tcp_ports)))) {
return;
}
bzero(&t_ports, sizeof(struct tcp_ports));
m_copydata(m, off, sizeof(struct tcp_ports), (caddr_t)&t_ports);
inp = in6_pcblookup(&V_tcbinfo, &ip6->ip6_dst, t_ports.th_dport,
&ip6->ip6_src, t_ports.th_sport, INPLOOKUP_WLOCKPCB, NULL);
if (inp != NULL && PRC_IS_REDIRECT(cmd)) {
/* signal EHOSTDOWN, as it flushes the cached route */
inp = (*notify)(inp, EHOSTDOWN);
goto out;
}
off += sizeof(struct tcp_ports);
if (m->m_pkthdr.len < (int32_t) (off + sizeof(tcp_seq))) {
goto out;
}
m_copydata(m, off, sizeof(tcp_seq), (caddr_t)&icmp_tcp_seq);
if (inp != NULL) {
if (!(inp->inp_flags & INP_TIMEWAIT) &&
!(inp->inp_flags & INP_DROPPED) &&
!(inp->inp_socket == NULL)) {
tp = intotcpcb(inp);
if (SEQ_GEQ(ntohl(icmp_tcp_seq), tp->snd_una) &&
SEQ_LT(ntohl(icmp_tcp_seq), tp->snd_max)) {
if (cmd == PRC_MSGSIZE) {
/*
* MTU discovery:
* If we got a needfrag set the MTU
* in the route to the suggested new
* value (if given) and then notify.
*/
mtu = ntohl(icmp6->icmp6_mtu);
/*
* If no alternative MTU was
* proposed, or the proposed
* MTU was too small, set to
* the min.
*/
if (mtu < IPV6_MMTU)
mtu = IPV6_MMTU - 8;
bzero(&inc, sizeof(inc));
inc.inc_fibnum = M_GETFIB(m);
inc.inc_flags |= INC_ISIPV6;
inc.inc6_faddr = *dst;
if (in6_setscope(&inc.inc6_faddr,
m->m_pkthdr.rcvif, NULL))
goto out;
/*
* Only process the offered MTU if it
* is smaller than the current one.
*/
if (mtu < tp->t_maxseg +
sizeof (struct tcphdr) +
sizeof (struct ip6_hdr)) {
tcp_hc_updatemtu(&inc, mtu);
tcp_mtudisc(inp, mtu);
ICMP6STAT_INC(icp6s_pmtuchg);
}
} else
inp = (*notify)(inp,
inet6ctlerrmap[cmd]);
}
}
} else {
bzero(&inc, sizeof(inc));
inc.inc_fibnum = M_GETFIB(m);
inc.inc_flags |= INC_ISIPV6;
inc.inc_fport = t_ports.th_dport;
inc.inc_lport = t_ports.th_sport;
inc.inc6_faddr = *dst;
inc.inc6_laddr = ip6->ip6_src;
syncache_unreach(&inc, icmp_tcp_seq);
}
out:
if (inp != NULL)
INP_WUNLOCK(inp);
}
#endif /* INET6 */
static uint32_t
tcp_keyed_hash(struct in_conninfo *inc, u_char *key, u_int len)
{
SIPHASH_CTX ctx;
uint32_t hash[2];
KASSERT(len >= SIPHASH_KEY_LENGTH,
("%s: keylen %u too short ", __func__, len));
SipHash24_Init(&ctx);
SipHash_SetKey(&ctx, (uint8_t *)key);
SipHash_Update(&ctx, &inc->inc_fport, sizeof(uint16_t));
SipHash_Update(&ctx, &inc->inc_lport, sizeof(uint16_t));
switch (inc->inc_flags & INC_ISIPV6) {
#ifdef INET
case 0:
SipHash_Update(&ctx, &inc->inc_faddr, sizeof(struct in_addr));
SipHash_Update(&ctx, &inc->inc_laddr, sizeof(struct in_addr));
break;
#endif
#ifdef INET6
case INC_ISIPV6:
SipHash_Update(&ctx, &inc->inc6_faddr, sizeof(struct in6_addr));
SipHash_Update(&ctx, &inc->inc6_laddr, sizeof(struct in6_addr));
break;
#endif
}
SipHash_Final((uint8_t *)hash, &ctx);
return (hash[0] ^ hash[1]);
}
uint32_t
tcp_new_ts_offset(struct in_conninfo *inc)
{
struct in_conninfo inc_store, *local_inc;
if (!V_tcp_ts_offset_per_conn) {
memcpy(&inc_store, inc, sizeof(struct in_conninfo));
inc_store.inc_lport = 0;
inc_store.inc_fport = 0;
local_inc = &inc_store;
} else {
local_inc = inc;
}
return (tcp_keyed_hash(local_inc, V_ts_offset_secret,
sizeof(V_ts_offset_secret)));
}
/*
* Following is where TCP initial sequence number generation occurs.
*
* There are two places where we must use initial sequence numbers:
* 1. In SYN-ACK packets.
* 2. In SYN packets.
*
* All ISNs for SYN-ACK packets are generated by the syncache. See
* tcp_syncache.c for details.
*
* The ISNs in SYN packets must be monotonic; TIME_WAIT recycling
* depends on this property. In addition, these ISNs should be
* unguessable so as to prevent connection hijacking. To satisfy
* the requirements of this situation, the algorithm outlined in
* RFC 1948 is used, with only small modifications.
*
* Implementation details:
*
* Time is based off the system timer, and is corrected so that it
* increases by one megabyte per second. This allows for proper
* recycling on high speed LANs while still leaving over an hour
* before rollover.
*
* As reading the *exact* system time is too expensive to be done
* whenever setting up a TCP connection, we increment the time
* offset in two ways. First, a small random positive increment
* is added to isn_offset for each connection that is set up.
* Second, the function tcp_isn_tick fires once per clock tick
* and increments isn_offset as necessary so that sequence numbers
* are incremented at approximately ISN_BYTES_PER_SECOND. The
* random positive increments serve only to ensure that the same
* exact sequence number is never sent out twice (as could otherwise
* happen when a port is recycled in less than the system tick
* interval.)
*
* net.inet.tcp.isn_reseed_interval controls the number of seconds
* between seeding of isn_secret. This is normally set to zero,
* as reseeding should not be necessary.
*
* Locking of the global variables isn_secret, isn_last_reseed, isn_offset,
* isn_offset_old, and isn_ctx is performed using the ISN lock. In
* general, this means holding an exclusive (write) lock.
*/
#define ISN_BYTES_PER_SECOND 1048576
#define ISN_STATIC_INCREMENT 4096
#define ISN_RANDOM_INCREMENT (4096 - 1)
#define ISN_SECRET_LENGTH SIPHASH_KEY_LENGTH
VNET_DEFINE_STATIC(u_char, isn_secret[ISN_SECRET_LENGTH]);
VNET_DEFINE_STATIC(int, isn_last);
VNET_DEFINE_STATIC(int, isn_last_reseed);
VNET_DEFINE_STATIC(u_int32_t, isn_offset);
VNET_DEFINE_STATIC(u_int32_t, isn_offset_old);
#define V_isn_secret VNET(isn_secret)
#define V_isn_last VNET(isn_last)
#define V_isn_last_reseed VNET(isn_last_reseed)
#define V_isn_offset VNET(isn_offset)
#define V_isn_offset_old VNET(isn_offset_old)
tcp_seq
tcp_new_isn(struct in_conninfo *inc)
{
tcp_seq new_isn;
u_int32_t projected_offset;
ISN_LOCK();
/* Seed if this is the first use, reseed if requested. */
if ((V_isn_last_reseed == 0) || ((V_tcp_isn_reseed_interval > 0) &&
(((u_int)V_isn_last_reseed + (u_int)V_tcp_isn_reseed_interval*hz)
< (u_int)ticks))) {
arc4rand(&V_isn_secret, sizeof(V_isn_secret), 0);
V_isn_last_reseed = ticks;
}
/* Compute the hash and return the ISN. */
new_isn = (tcp_seq)tcp_keyed_hash(inc, V_isn_secret,
sizeof(V_isn_secret));
V_isn_offset += ISN_STATIC_INCREMENT +
(arc4random() & ISN_RANDOM_INCREMENT);
if (ticks != V_isn_last) {
projected_offset = V_isn_offset_old +
ISN_BYTES_PER_SECOND / hz * (ticks - V_isn_last);
if (SEQ_GT(projected_offset, V_isn_offset))
V_isn_offset = projected_offset;
V_isn_offset_old = V_isn_offset;
V_isn_last = ticks;
}
new_isn += V_isn_offset;
ISN_UNLOCK();
return (new_isn);
}
/*
* When a specific ICMP unreachable message is received and the
* connection state is SYN-SENT, drop the connection. This behavior
* is controlled by the icmp_may_rst sysctl.
*/
struct inpcb *
tcp_drop_syn_sent(struct inpcb *inp, int errno)
{
struct tcpcb *tp;
NET_EPOCH_ASSERT();
INP_WLOCK_ASSERT(inp);
if ((inp->inp_flags & INP_TIMEWAIT) ||
(inp->inp_flags & INP_DROPPED))
return (inp);
tp = intotcpcb(inp);
if (tp->t_state != TCPS_SYN_SENT)
return (inp);
if (IS_FASTOPEN(tp->t_flags))
tcp_fastopen_disable_path(tp);
tp = tcp_drop(tp, errno);
if (tp != NULL)
return (inp);
else
return (NULL);
}
/*
* When `need fragmentation' ICMP is received, update our idea of the MSS
* based on the new value. Also nudge TCP to send something, since we
* know the packet we just sent was dropped.
* This duplicates some code in the tcp_mss() function in tcp_input.c.
*/
static struct inpcb *
tcp_mtudisc_notify(struct inpcb *inp, int error)
{
tcp_mtudisc(inp, -1);
return (inp);
}
static void
tcp_mtudisc(struct inpcb *inp, int mtuoffer)
{
struct tcpcb *tp;
struct socket *so;
INP_WLOCK_ASSERT(inp);
if ((inp->inp_flags & INP_TIMEWAIT) ||
(inp->inp_flags & INP_DROPPED))
return;
tp = intotcpcb(inp);
KASSERT(tp != NULL, ("tcp_mtudisc: tp == NULL"));
tcp_mss_update(tp, -1, mtuoffer, NULL, NULL);
so = inp->inp_socket;
SOCKBUF_LOCK(&so->so_snd);
/* If the mss is larger than the socket buffer, decrease the mss. */
if (so->so_snd.sb_hiwat < tp->t_maxseg)
tp->t_maxseg = so->so_snd.sb_hiwat;
SOCKBUF_UNLOCK(&so->so_snd);
TCPSTAT_INC(tcps_mturesent);
tp->t_rtttime = 0;
tp->snd_nxt = tp->snd_una;
tcp_free_sackholes(tp);
tp->snd_recover = tp->snd_max;
if (tp->t_flags & TF_SACK_PERMIT)
EXIT_FASTRECOVERY(tp->t_flags);
tp->t_fb->tfb_tcp_output(tp);
}
#ifdef INET
/*
* Look-up the routing entry to the peer of this inpcb. If no route
* is found and it cannot be allocated, then return 0. This routine
* is called by TCP routines that access the rmx structure and by
* tcp_mss_update to get the peer/interface MTU.
*/
uint32_t
tcp_maxmtu(struct in_conninfo *inc, struct tcp_ifcap *cap)
{
struct nhop_object *nh;
struct ifnet *ifp;
uint32_t maxmtu = 0;
KASSERT(inc != NULL, ("tcp_maxmtu with NULL in_conninfo pointer"));
if (inc->inc_faddr.s_addr != INADDR_ANY) {
nh = fib4_lookup(inc->inc_fibnum, inc->inc_faddr, 0, NHR_NONE, 0);
if (nh == NULL)
return (0);
ifp = nh->nh_ifp;
maxmtu = nh->nh_mtu;
/* Report additional interface capabilities. */
if (cap != NULL) {
if (ifp->if_capenable & IFCAP_TSO4 &&
ifp->if_hwassist & CSUM_TSO) {
cap->ifcap |= CSUM_TSO;
cap->tsomax = ifp->if_hw_tsomax;
cap->tsomaxsegcount = ifp->if_hw_tsomaxsegcount;
cap->tsomaxsegsize = ifp->if_hw_tsomaxsegsize;
}
}
}
return (maxmtu);
}
#endif /* INET */
#ifdef INET6
uint32_t
tcp_maxmtu6(struct in_conninfo *inc, struct tcp_ifcap *cap)
{
struct nhop_object *nh;
struct in6_addr dst6;
uint32_t scopeid;
struct ifnet *ifp;
uint32_t maxmtu = 0;
KASSERT(inc != NULL, ("tcp_maxmtu6 with NULL in_conninfo pointer"));
if (inc->inc_flags & INC_IPV6MINMTU)
return (IPV6_MMTU);
if (!IN6_IS_ADDR_UNSPECIFIED(&inc->inc6_faddr)) {
in6_splitscope(&inc->inc6_faddr, &dst6, &scopeid);
nh = fib6_lookup(inc->inc_fibnum, &dst6, scopeid, NHR_NONE, 0);
if (nh == NULL)
return (0);
ifp = nh->nh_ifp;
maxmtu = nh->nh_mtu;
/* Report additional interface capabilities. */
if (cap != NULL) {
if (ifp->if_capenable & IFCAP_TSO6 &&
ifp->if_hwassist & CSUM_TSO) {
cap->ifcap |= CSUM_TSO;
cap->tsomax = ifp->if_hw_tsomax;
cap->tsomaxsegcount = ifp->if_hw_tsomaxsegcount;
cap->tsomaxsegsize = ifp->if_hw_tsomaxsegsize;
}
}
}
return (maxmtu);
}
#endif /* INET6 */
/*
* Calculate effective SMSS per RFC5681 definition for a given TCP
* connection at its current state, taking into account SACK and etc.
*/
u_int
tcp_maxseg(const struct tcpcb *tp)
{
u_int optlen;
if (tp->t_flags & TF_NOOPT)
return (tp->t_maxseg);
/*
* Here we have a simplified code from tcp_addoptions(),
* without a proper loop, and having most of paddings hardcoded.
* We might make mistakes with padding here in some edge cases,
* but this is harmless, since result of tcp_maxseg() is used
* only in cwnd and ssthresh estimations.
*/
if (TCPS_HAVEESTABLISHED(tp->t_state)) {
if (tp->t_flags & TF_RCVD_TSTMP)
optlen = TCPOLEN_TSTAMP_APPA;
else
optlen = 0;
#if defined(IPSEC_SUPPORT) || defined(TCP_SIGNATURE)
if (tp->t_flags & TF_SIGNATURE)
optlen += PADTCPOLEN(TCPOLEN_SIGNATURE);
#endif
if ((tp->t_flags & TF_SACK_PERMIT) && tp->rcv_numsacks > 0) {
optlen += TCPOLEN_SACKHDR;
optlen += tp->rcv_numsacks * TCPOLEN_SACK;
optlen = PADTCPOLEN(optlen);
}
} else {
if (tp->t_flags & TF_REQ_TSTMP)
optlen = TCPOLEN_TSTAMP_APPA;
else
optlen = PADTCPOLEN(TCPOLEN_MAXSEG);
if (tp->t_flags & TF_REQ_SCALE)
optlen += PADTCPOLEN(TCPOLEN_WINDOW);
#if defined(IPSEC_SUPPORT) || defined(TCP_SIGNATURE)
if (tp->t_flags & TF_SIGNATURE)
optlen += PADTCPOLEN(TCPOLEN_SIGNATURE);
#endif
if (tp->t_flags & TF_SACK_PERMIT)
optlen += PADTCPOLEN(TCPOLEN_SACK_PERMITTED);
}
#undef PAD
optlen = min(optlen, TCP_MAXOLEN);
return (tp->t_maxseg - optlen);
}
static int
sysctl_drop(SYSCTL_HANDLER_ARGS)
{
/* addrs[0] is a foreign socket, addrs[1] is a local one. */
struct sockaddr_storage addrs[2];
struct inpcb *inp;
struct tcpcb *tp;
struct tcptw *tw;
struct sockaddr_in *fin, *lin;
struct epoch_tracker et;
#ifdef INET6
struct sockaddr_in6 *fin6, *lin6;
#endif
int error;
inp = NULL;
fin = lin = NULL;
#ifdef INET6
fin6 = lin6 = NULL;
#endif
error = 0;
if (req->oldptr != NULL || req->oldlen != 0)
return (EINVAL);
if (req->newptr == NULL)
return (EPERM);
if (req->newlen < sizeof(addrs))
return (ENOMEM);
error = SYSCTL_IN(req, &addrs, sizeof(addrs));
if (error)
return (error);
switch (addrs[0].ss_family) {
#ifdef INET6
case AF_INET6:
fin6 = (struct sockaddr_in6 *)&addrs[0];
lin6 = (struct sockaddr_in6 *)&addrs[1];
if (fin6->sin6_len != sizeof(struct sockaddr_in6) ||
lin6->sin6_len != sizeof(struct sockaddr_in6))
return (EINVAL);
if (IN6_IS_ADDR_V4MAPPED(&fin6->sin6_addr)) {
if (!IN6_IS_ADDR_V4MAPPED(&lin6->sin6_addr))
return (EINVAL);
in6_sin6_2_sin_in_sock((struct sockaddr *)&addrs[0]);
in6_sin6_2_sin_in_sock((struct sockaddr *)&addrs[1]);
fin = (struct sockaddr_in *)&addrs[0];
lin = (struct sockaddr_in *)&addrs[1];
break;
}
error = sa6_embedscope(fin6, V_ip6_use_defzone);
if (error)
return (error);
error = sa6_embedscope(lin6, V_ip6_use_defzone);
if (error)
return (error);
break;
#endif
#ifdef INET
case AF_INET:
fin = (struct sockaddr_in *)&addrs[0];
lin = (struct sockaddr_in *)&addrs[1];
if (fin->sin_len != sizeof(struct sockaddr_in) ||
lin->sin_len != sizeof(struct sockaddr_in))
return (EINVAL);
break;
#endif
default:
return (EINVAL);
}
NET_EPOCH_ENTER(et);
switch (addrs[0].ss_family) {
#ifdef INET6
case AF_INET6:
inp = in6_pcblookup(&V_tcbinfo, &fin6->sin6_addr,
fin6->sin6_port, &lin6->sin6_addr, lin6->sin6_port,
INPLOOKUP_WLOCKPCB, NULL);
break;
#endif
#ifdef INET
case AF_INET:
inp = in_pcblookup(&V_tcbinfo, fin->sin_addr, fin->sin_port,
lin->sin_addr, lin->sin_port, INPLOOKUP_WLOCKPCB, NULL);
break;
#endif
}
if (inp != NULL) {
if (inp->inp_flags & INP_TIMEWAIT) {
/*
* XXXRW: There currently exists a state where an
* inpcb is present, but its timewait state has been
* discarded. For now, don't allow dropping of this
* type of inpcb.
*/
tw = intotw(inp);
if (tw != NULL)
tcp_twclose(tw, 0);
else
INP_WUNLOCK(inp);
} else if (!(inp->inp_flags & INP_DROPPED) &&
!(inp->inp_socket->so_options & SO_ACCEPTCONN)) {
tp = intotcpcb(inp);
tp = tcp_drop(tp, ECONNABORTED);
if (tp != NULL)
INP_WUNLOCK(inp);
} else
INP_WUNLOCK(inp);
} else
error = ESRCH;
NET_EPOCH_EXIT(et);
return (error);
}
SYSCTL_PROC(_net_inet_tcp, TCPCTL_DROP, drop,
CTLFLAG_VNET | CTLTYPE_STRUCT | CTLFLAG_WR | CTLFLAG_SKIP |
CTLFLAG_NEEDGIANT, NULL, 0, sysctl_drop, "",
"Drop TCP connection");
#ifdef KERN_TLS
static int
sysctl_switch_tls(SYSCTL_HANDLER_ARGS)
{
/* addrs[0] is a foreign socket, addrs[1] is a local one. */
struct sockaddr_storage addrs[2];
struct inpcb *inp;
struct sockaddr_in *fin, *lin;
struct epoch_tracker et;
#ifdef INET6
struct sockaddr_in6 *fin6, *lin6;
#endif
int error;
inp = NULL;
fin = lin = NULL;
#ifdef INET6
fin6 = lin6 = NULL;
#endif
error = 0;
if (req->oldptr != NULL || req->oldlen != 0)
return (EINVAL);
if (req->newptr == NULL)
return (EPERM);
if (req->newlen < sizeof(addrs))
return (ENOMEM);
error = SYSCTL_IN(req, &addrs, sizeof(addrs));
if (error)
return (error);
switch (addrs[0].ss_family) {
#ifdef INET6
case AF_INET6:
fin6 = (struct sockaddr_in6 *)&addrs[0];
lin6 = (struct sockaddr_in6 *)&addrs[1];
if (fin6->sin6_len != sizeof(struct sockaddr_in6) ||
lin6->sin6_len != sizeof(struct sockaddr_in6))
return (EINVAL);
if (IN6_IS_ADDR_V4MAPPED(&fin6->sin6_addr)) {
if (!IN6_IS_ADDR_V4MAPPED(&lin6->sin6_addr))
return (EINVAL);
in6_sin6_2_sin_in_sock((struct sockaddr *)&addrs[0]);
in6_sin6_2_sin_in_sock((struct sockaddr *)&addrs[1]);
fin = (struct sockaddr_in *)&addrs[0];
lin = (struct sockaddr_in *)&addrs[1];
break;
}
error = sa6_embedscope(fin6, V_ip6_use_defzone);
if (error)
return (error);
error = sa6_embedscope(lin6, V_ip6_use_defzone);
if (error)
return (error);
break;
#endif
#ifdef INET
case AF_INET:
fin = (struct sockaddr_in *)&addrs[0];
lin = (struct sockaddr_in *)&addrs[1];
if (fin->sin_len != sizeof(struct sockaddr_in) ||
lin->sin_len != sizeof(struct sockaddr_in))
return (EINVAL);
break;
#endif
default:
return (EINVAL);
}
NET_EPOCH_ENTER(et);
switch (addrs[0].ss_family) {
#ifdef INET6
case AF_INET6:
inp = in6_pcblookup(&V_tcbinfo, &fin6->sin6_addr,
fin6->sin6_port, &lin6->sin6_addr, lin6->sin6_port,
INPLOOKUP_WLOCKPCB, NULL);
break;
#endif
#ifdef INET
case AF_INET:
inp = in_pcblookup(&V_tcbinfo, fin->sin_addr, fin->sin_port,
lin->sin_addr, lin->sin_port, INPLOOKUP_WLOCKPCB, NULL);
break;
#endif
}
NET_EPOCH_EXIT(et);
if (inp != NULL) {
if ((inp->inp_flags & (INP_TIMEWAIT | INP_DROPPED)) != 0 ||
inp->inp_socket == NULL) {
error = ECONNRESET;
INP_WUNLOCK(inp);
} else {
struct socket *so;
so = inp->inp_socket;
soref(so);
error = ktls_set_tx_mode(so,
arg2 == 0 ? TCP_TLS_MODE_SW : TCP_TLS_MODE_IFNET);
INP_WUNLOCK(inp);
SOCK_LOCK(so);
sorele(so);
}
} else
error = ESRCH;
return (error);
}
SYSCTL_PROC(_net_inet_tcp, OID_AUTO, switch_to_sw_tls,
CTLFLAG_VNET | CTLTYPE_STRUCT | CTLFLAG_WR | CTLFLAG_SKIP |
CTLFLAG_NEEDGIANT, NULL, 0, sysctl_switch_tls, "",
"Switch TCP connection to SW TLS");
SYSCTL_PROC(_net_inet_tcp, OID_AUTO, switch_to_ifnet_tls,
CTLFLAG_VNET | CTLTYPE_STRUCT | CTLFLAG_WR | CTLFLAG_SKIP |
CTLFLAG_NEEDGIANT, NULL, 1, sysctl_switch_tls, "",
"Switch TCP connection to ifnet TLS");
#endif
/*
* Generate a standardized TCP log line for use throughout the
* tcp subsystem. Memory allocation is done with M_NOWAIT to
* allow use in the interrupt context.
*
* NB: The caller MUST free(s, M_TCPLOG) the returned string.
* NB: The function may return NULL if memory allocation failed.
*
* Due to header inclusion and ordering limitations the struct ip
* and ip6_hdr pointers have to be passed as void pointers.
*/
char *
tcp_log_vain(struct in_conninfo *inc, struct tcphdr *th, void *ip4hdr,
const void *ip6hdr)
{
/* Is logging enabled? */
if (V_tcp_log_in_vain == 0)
return (NULL);
return (tcp_log_addr(inc, th, ip4hdr, ip6hdr));
}
char *
tcp_log_addrs(struct in_conninfo *inc, struct tcphdr *th, void *ip4hdr,
const void *ip6hdr)
{
/* Is logging enabled? */
if (tcp_log_debug == 0)
return (NULL);
return (tcp_log_addr(inc, th, ip4hdr, ip6hdr));
}
static char *
tcp_log_addr(struct in_conninfo *inc, struct tcphdr *th, void *ip4hdr,
const void *ip6hdr)
{
char *s, *sp;
size_t size;
struct ip *ip;
#ifdef INET6
const struct ip6_hdr *ip6;
ip6 = (const struct ip6_hdr *)ip6hdr;
#endif /* INET6 */
ip = (struct ip *)ip4hdr;
/*
* The log line looks like this:
* "TCP: [1.2.3.4]:50332 to [1.2.3.4]:80 tcpflags 0x2<SYN>"
*/
size = sizeof("TCP: []:12345 to []:12345 tcpflags 0x2<>") +
sizeof(PRINT_TH_FLAGS) + 1 +
#ifdef INET6
2 * INET6_ADDRSTRLEN;
#else
2 * INET_ADDRSTRLEN;
#endif /* INET6 */
s = malloc(size, M_TCPLOG, M_ZERO|M_NOWAIT);
if (s == NULL)
return (NULL);
strcat(s, "TCP: [");
sp = s + strlen(s);
if (inc && ((inc->inc_flags & INC_ISIPV6) == 0)) {
inet_ntoa_r(inc->inc_faddr, sp);
sp = s + strlen(s);
sprintf(sp, "]:%i to [", ntohs(inc->inc_fport));
sp = s + strlen(s);
inet_ntoa_r(inc->inc_laddr, sp);
sp = s + strlen(s);
sprintf(sp, "]:%i", ntohs(inc->inc_lport));
#ifdef INET6
} else if (inc) {
ip6_sprintf(sp, &inc->inc6_faddr);
sp = s + strlen(s);
sprintf(sp, "]:%i to [", ntohs(inc->inc_fport));
sp = s + strlen(s);
ip6_sprintf(sp, &inc->inc6_laddr);
sp = s + strlen(s);
sprintf(sp, "]:%i", ntohs(inc->inc_lport));
} else if (ip6 && th) {
ip6_sprintf(sp, &ip6->ip6_src);
sp = s + strlen(s);
sprintf(sp, "]:%i to [", ntohs(th->th_sport));
sp = s + strlen(s);
ip6_sprintf(sp, &ip6->ip6_dst);
sp = s + strlen(s);
sprintf(sp, "]:%i", ntohs(th->th_dport));
#endif /* INET6 */
#ifdef INET
} else if (ip && th) {
inet_ntoa_r(ip->ip_src, sp);
sp = s + strlen(s);
sprintf(sp, "]:%i to [", ntohs(th->th_sport));
sp = s + strlen(s);
inet_ntoa_r(ip->ip_dst, sp);
sp = s + strlen(s);
sprintf(sp, "]:%i", ntohs(th->th_dport));
#endif /* INET */
} else {
free(s, M_TCPLOG);
return (NULL);
}
sp = s + strlen(s);
if (th)
sprintf(sp, " tcpflags 0x%b", th->th_flags, PRINT_TH_FLAGS);
if (*(s + size - 1) != '\0')
panic("%s: string too long", __func__);
return (s);
}
/*
* A subroutine which makes it easy to track TCP state changes with DTrace.
* This function shouldn't be called for t_state initializations that don't
* correspond to actual TCP state transitions.
*/
void
tcp_state_change(struct tcpcb *tp, int newstate)
{
#if defined(KDTRACE_HOOKS)
int pstate = tp->t_state;
#endif
TCPSTATES_DEC(tp->t_state);
TCPSTATES_INC(newstate);
tp->t_state = newstate;
TCP_PROBE6(state__change, NULL, tp, NULL, tp, NULL, pstate);
}
/*
* Create an external-format (``xtcpcb'') structure using the information in
* the kernel-format tcpcb structure pointed to by tp. This is done to
* reduce the spew of irrelevant information over this interface, to isolate
* user code from changes in the kernel structure, and potentially to provide
* information-hiding if we decide that some of this information should be
* hidden from users.
*/
void
tcp_inptoxtp(const struct inpcb *inp, struct xtcpcb *xt)
{
struct tcpcb *tp = intotcpcb(inp);
sbintime_t now;
bzero(xt, sizeof(*xt));
if (inp->inp_flags & INP_TIMEWAIT) {
xt->t_state = TCPS_TIME_WAIT;
} else {
xt->t_state = tp->t_state;
xt->t_logstate = tp->t_logstate;
xt->t_flags = tp->t_flags;
xt->t_sndzerowin = tp->t_sndzerowin;
xt->t_sndrexmitpack = tp->t_sndrexmitpack;
xt->t_rcvoopack = tp->t_rcvoopack;
xt->t_rcv_wnd = tp->rcv_wnd;
xt->t_snd_wnd = tp->snd_wnd;
xt->t_snd_cwnd = tp->snd_cwnd;
xt->t_snd_ssthresh = tp->snd_ssthresh;
xt->t_maxseg = tp->t_maxseg;
xt->xt_ecn = (tp->t_flags2 & TF2_ECN_PERMIT) ? 1 : 0 +
(tp->t_flags2 & TF2_ACE_PERMIT) ? 2 : 0;
now = getsbinuptime();
#define COPYTIMER(ttt) do { \
if (callout_active(&tp->t_timers->ttt)) \
xt->ttt = (tp->t_timers->ttt.c_time - now) / \
SBT_1MS; \
else \
xt->ttt = 0; \
} while (0)
COPYTIMER(tt_delack);
COPYTIMER(tt_rexmt);
COPYTIMER(tt_persist);
COPYTIMER(tt_keep);
COPYTIMER(tt_2msl);
#undef COPYTIMER
xt->t_rcvtime = 1000 * (ticks - tp->t_rcvtime) / hz;
bcopy(tp->t_fb->tfb_tcp_block_name, xt->xt_stack,
TCP_FUNCTION_NAME_LEN_MAX);
bcopy(CC_ALGO(tp)->name, xt->xt_cc,
TCP_CA_NAME_MAX);
#ifdef TCP_BLACKBOX
(void)tcp_log_get_id(tp, xt->xt_logid);
#endif
}
xt->xt_len = sizeof(struct xtcpcb);
in_pcbtoxinpcb(inp, &xt->xt_inp);
if (inp->inp_socket == NULL)
xt->xt_inp.xi_socket.xso_protocol = IPPROTO_TCP;
}
void
tcp_log_end_status(struct tcpcb *tp, uint8_t status)
{
uint32_t bit, i;
if ((tp == NULL) ||
(status > TCP_EI_STATUS_MAX_VALUE) ||
(status == 0)) {
/* Invalid */
return;
}
if (status > (sizeof(uint32_t) * 8)) {
/* Should this be a KASSERT? */
return;
}
bit = 1U << (status - 1);
if (bit & tp->t_end_info_status) {
/* already logged */
return;
}
for (i = 0; i < TCP_END_BYTE_INFO; i++) {
if (tp->t_end_info_bytes[i] == TCP_EI_EMPTY_SLOT) {
tp->t_end_info_bytes[i] = status;
tp->t_end_info_status |= bit;
break;
}
}
}
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