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freebsd-skq/sys/netinet/tcp_subr.c
Richard Scheffenegger 5432120028 Extend netstat to display TCP stack and detailed congestion state (2) 
Extend netstat to display TCP stack and detailed congestion state

Adding the "-c" option used to show detailed per-connection
congestion control state for TCP sessions.

This is one summary patch, which adds the relevant variables into
xtcpcb. As previous "spare" space is used, these changes are ABI
compatible.

Reviewed by:	tuexen
MFC after:	2 weeks
Sponsored by:	NetApp, Inc.
Differential Revision:	https://reviews.freebsd.org/D26518
2020-10-09 10:55:19 +00:00

3507 lines
92 KiB
C
Raw Blame History

/*-
* 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
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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