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freebsd-nq/sys/netinet/tcp_subr.c
Gleb Smirnoff ef341ee1e3 When we receive an ICMP unreach need fragmentation datagram, we take 
proposed MTU value from it and update the TCP host cache. Then
tcp_mss_update() is called on the corresponding tcpcb. It finds the
just allocated entry in the TCP host cache and updates MSS on the
tcpcb. And then we do a fast retransmit of what we have in the tcp
send buffer.

This sequence gets broken if the TCP host cache is exausted. In this
case allocation fails, and later called tcp_mss_update() finds nothing
in cache. The fast retransmit is done with not reduced MSS and is
immidiately replied by remote host with new ICMP datagrams and the
cycle repeats. This ping-pong can go up to wirespeed.

To fix this:
- tcp_mss_update() gets new parameter - mtuoffer, that is like
  offer, but needs to have min_protoh subtracted.
- tcp_mtudisc() as notification method renamed to tcp_mtudisc_notify().
- tcp_mtudisc() now accepts not a useless error argument, but proposed
  MTU value, that is passed to tcp_mss_update() as mtuoffer.

Reported by:	az
Reported by:	Andrey Zonov <andrey zonov.org>
Reviewed by:	andre (previous version of patch)
2012-04-16 13:49:03 +00:00

2315 lines
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/*-
* 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.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)tcp_subr.c 8.2 (Berkeley) 5/24/95
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_compat.h"
#include "opt_inet.h"
#include "opt_inet6.h"
#include "opt_ipsec.h"
#include "opt_tcpdebug.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/callout.h>
#include <sys/hhook.h>
#include <sys/kernel.h>
#include <sys/khelp.h>
#include <sys/sysctl.h>
#include <sys/jail.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#ifdef INET6
#include <sys/domain.h>
#endif
#include <sys/priv.h>
#include <sys/proc.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/if.h>
#include <net/vnet.h>
#include <netinet/cc.h>
#include <netinet/in.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/ip6.h>
#include <netinet6/in6_pcb.h>
#include <netinet6/ip6_var.h>
#include <netinet6/scope6_var.h>
#include <netinet6/nd6.h>
#endif
#include <netinet/tcp_fsm.h>
#include <netinet/tcp_seq.h>
#include <netinet/tcp_timer.h>
#include <netinet/tcp_var.h>
#include <netinet/tcp_syncache.h>
#include <netinet/tcp_offload.h>
#ifdef INET6
#include <netinet6/tcp6_var.h>
#endif
#include <netinet/tcpip.h>
#ifdef TCPDEBUG
#include <netinet/tcp_debug.h>
#endif
#ifdef INET6
#include <netinet6/ip6protosw.h>
#endif
#ifdef IPSEC
#include <netipsec/ipsec.h>
#include <netipsec/xform.h>
#ifdef INET6
#include <netipsec/ipsec6.h>
#endif
#include <netipsec/key.h>
#include <sys/syslog.h>
#endif /*IPSEC*/
#include <machine/in_cksum.h>
#include <sys/md5.h>
#include <security/mac/mac_framework.h>
VNET_DEFINE(int, tcp_mssdflt) = TCP_MSS;
#ifdef INET6
VNET_DEFINE(int, tcp_v6mssdflt) = TCP6_MSS;
#endif
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_VNET_PROC(_net_inet_tcp, TCPCTL_MSSDFLT, mssdflt,
CTLTYPE_INT|CTLFLAG_RW, &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_VNET_PROC(_net_inet_tcp, TCPCTL_V6MSSDFLT, v6mssdflt,
CTLTYPE_INT|CTLFLAG_RW, &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_VNET_INT(_net_inet_tcp, OID_AUTO, minmss, CTLFLAG_RW,
&VNET_NAME(tcp_minmss), 0,
"Minmum TCP Maximum Segment Size");
VNET_DEFINE(int, tcp_do_rfc1323) = 1;
SYSCTL_VNET_INT(_net_inet_tcp, TCPCTL_DO_RFC1323, rfc1323, CTLFLAG_RW,
&VNET_NAME(tcp_do_rfc1323), 0,
"Enable rfc1323 (high performance TCP) extensions");
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 = 0;
SYSCTL_INT(_net_inet_tcp, OID_AUTO, tcbhashsize, CTLFLAG_RDTUN,
&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_VNET_UINT(_net_inet_tcp, OID_AUTO, pcbcount, CTLFLAG_RD,
&VNET_NAME(tcbinfo.ipi_count), 0, "Number of active PCBs");
static VNET_DEFINE(int, icmp_may_rst) = 1;
#define V_icmp_may_rst VNET(icmp_may_rst)
SYSCTL_VNET_INT(_net_inet_tcp, OID_AUTO, icmp_may_rst, CTLFLAG_RW,
&VNET_NAME(icmp_may_rst), 0,
"Certain ICMP unreachable messages may abort connections in SYN_SENT");
static VNET_DEFINE(int, tcp_isn_reseed_interval) = 0;
#define V_tcp_isn_reseed_interval VNET(tcp_isn_reseed_interval)
SYSCTL_VNET_INT(_net_inet_tcp, OID_AUTO, isn_reseed_interval, CTLFLAG_RW,
&VNET_NAME(tcp_isn_reseed_interval), 0,
"Seconds between reseeding of ISN secret");
static int tcp_soreceive_stream = 0;
SYSCTL_INT(_net_inet_tcp, OID_AUTO, soreceive_stream, CTLFLAG_RDTUN,
&tcp_soreceive_stream, 0, "Using soreceive_stream for TCP sockets");
#ifdef TCP_SIGNATURE
static int tcp_sig_checksigs = 1;
SYSCTL_INT(_net_inet_tcp, OID_AUTO, signature_verify_input, CTLFLAG_RW,
&tcp_sig_checksigs, 0, "Verify RFC2385 digests on inbound traffic");
#endif
VNET_DEFINE(uma_zone_t, sack_hole_zone);
#define V_sack_hole_zone VNET(sack_hole_zone)
VNET_DEFINE(struct hhook_head *, tcp_hhh[HHOOK_TCP_LAST+1]);
static struct inpcb *tcp_notify(struct inpcb *, int);
static struct inpcb *tcp_mtudisc_notify(struct inpcb *, int);
static char * tcp_log_addr(struct in_conninfo *inc, struct tcphdr *th,
void *ip4hdr, const void *ip6hdr);
/*
* 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 512
#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;
struct osd osd;
};
static VNET_DEFINE(uma_zone_t, tcpcb_zone);
#define V_tcpcb_zone VNET(tcpcb_zone)
MALLOC_DEFINE(M_TCPLOG, "tcplog", "TCP address and flags print buffers");
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);
}
void
tcp_init(void)
{
int hashsize;
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__);
hashsize = TCBHASHSIZE;
TUNABLE_INT_FETCH("net.inet.tcp.tcbhashsize", &hashsize);
if (!powerof2(hashsize)) {
printf("WARNING: TCB hash size not a power of 2\n");
hashsize = 512; /* safe default */
}
in_pcbinfo_init(&V_tcbinfo, "tcp", &V_tcb, hashsize, hashsize,
"tcp_inpcb", tcp_inpcb_init, NULL, UMA_ZONE_NOFREE,
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, UMA_ZONE_NOFREE);
uma_zone_set_max(V_tcpcb_zone, maxsockets);
tcp_tw_init();
syncache_init();
tcp_hc_init();
tcp_reass_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, UMA_ZONE_NOFREE);
/* Skip initialization of globals for non-default instances. */
if (!IS_DEFAULT_VNET(curvnet))
return;
/* 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_min = TCPTV_MIN;
if (tcp_rexmit_min < 1)
tcp_rexmit_min = 1;
tcp_rexmit_slop = TCPTV_CPU_VAR;
tcp_finwait2_timeout = TCPTV_FINWAIT2_TIMEOUT;
tcp_tcbhashsize = hashsize;
TUNABLE_INT_FETCH("net.inet.tcp.soreceive_stream", &tcp_soreceive_stream);
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);
}
#ifdef VIMAGE
void
tcp_destroy(void)
{
tcp_reass_destroy();
tcp_hc_destroy();
syncache_destroy();
tcp_tw_destroy();
in_pcbinfo_destroy(&V_tcbinfo);
uma_zdestroy(V_sack_hole_zone);
uma_zdestroy(V_tcpcb_zone);
}
#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 ti 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 ti,
* 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 ti 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)
{
int tlen;
int win = 0;
struct ip *ip;
struct tcphdr *nth;
#ifdef INET6
struct ip6_hdr *ip6;
int isipv6;
#endif /* INET6 */
int ipflags = 0;
struct inpcb *inp;
KASSERT(tp != NULL || m != NULL, ("tcp_respond: tp and m both NULL"));
#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;
if (tp != NULL) {
if (!(flags & TH_RST)) {
win = sbspace(&inp->inp_socket->so_rcv);
if (win > (long)TCP_MAXWIN << tp->rcv_scale)
win = (long)TCP_MAXWIN << tp->rcv_scale;
}
}
if (m == NULL) {
m = m_gethdr(M_DONTWAIT, MT_DATA);
if (m == NULL)
return;
tlen = 0;
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 {
/*
* reuse the mbuf.
* XXX MRT We inherrit the FIB, which is lucky.
*/
m_freem(m->m_next);
m->m_next = NULL;
m->m_data = (caddr_t)ipgen;
m_addr_changed(m);
/* m_len is set later */
tlen = 0;
#define xchg(a,b,type) { type t; t=a; a=b; b=t; }
#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
}
#ifdef INET6
if (isipv6) {
ip6->ip6_flow = 0;
ip6->ip6_vfc = IPV6_VERSION;
ip6->ip6_nxt = IPPROTO_TCP;
ip6->ip6_plen = htons((u_short)(sizeof (struct tcphdr) +
tlen));
tlen += sizeof (struct ip6_hdr) + sizeof (struct tcphdr);
}
#endif
#if defined(INET) && defined(INET6)
else
#endif
#ifdef INET
{
tlen += sizeof (struct tcpiphdr);
ip->ip_len = tlen;
ip->ip_ttl = V_ip_defttl;
if (V_path_mtu_discovery)
ip->ip_off |= IP_DF;
}
#endif
m->m_len = tlen;
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) >> 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;
#ifdef INET6
if (isipv6) {
nth->th_sum = 0;
nth->th_sum = in6_cksum(m, IPPROTO_TCP,
sizeof(struct ip6_hdr),
tlen - sizeof(struct ip6_hdr));
ip6->ip6_hlim = in6_selecthlim(tp != NULL ? tp->t_inpcb :
NULL, NULL);
}
#endif /* INET6 */
#if defined(INET6) && defined(INET)
else
#endif
#ifdef INET
{
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)));
m->m_pkthdr.csum_flags = CSUM_TCP;
m->m_pkthdr.csum_data = offsetof(struct tcphdr, th_sum);
}
#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
#ifdef INET6
if (isipv6)
(void) ip6_output(m, NULL, NULL, ipflags, NULL, NULL, inp);
#endif /* INET6 */
#if defined(INET) && defined(INET6)
else
#endif
#ifdef INET
(void) ip_output(m, NULL, NULL, ipflags, 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;
/*
* 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();
if (CC_ALGO(tp)->cb_init != NULL)
if (CC_ALGO(tp)->cb_init(tp->ccv) > 0) {
uma_zfree(V_tcpcb_zone, tm);
return (NULL);
}
tp->osd = &tm->osd;
if (khelp_init_osd(HELPER_CLASS_TCP, tp->osd)) {
uma_zfree(V_tcpcb_zone, tm);
return (NULL);
}
#ifdef VIMAGE
tp->t_vnet = inp->inp_vnet;
#endif
tp->t_timers = &tm->tt;
/* LIST_INIT(&tp->t_segq); */ /* XXX covered by M_ZERO */
tp->t_maxseg = tp->t_maxopd =
#ifdef INET6
isipv6 ? V_tcp_v6mssdflt :
#endif /* INET6 */
V_tcp_mssdflt;
/* Set up our timeouts. */
callout_init(&tp->t_timers->tt_rexmt, CALLOUT_MPSAFE);
callout_init(&tp->t_timers->tt_persist, CALLOUT_MPSAFE);
callout_init(&tp->t_timers->tt_keep, CALLOUT_MPSAFE);
callout_init(&tp->t_timers->tt_2msl, CALLOUT_MPSAFE);
callout_init(&tp->t_timers->tt_delack, CALLOUT_MPSAFE);
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);
tp->t_inpcb = inp; /* XXX */
/*
* 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 = ((TCPTV_RTOBASE - TCPTV_SRTTBASE) << TCP_RTTVAR_SHIFT) / 4;
tp->t_rttmin = tcp_rexmit_min;
tp->t_rxtcur = TCPTV_RTOBASE;
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;
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_RLOCK(&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.
*/
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);
/* NewReno does not require any init. */
CC_ALGO(tp) = &newreno_cc_algo;
if (tmpalgo->cb_destroy != NULL)
tmpalgo->cb_destroy(tp->ccv);
}
}
INP_WUNLOCK(inp);
}
INP_INFO_RUNLOCK(&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;
INP_INFO_WLOCK_ASSERT(&V_tcbinfo);
INP_WLOCK_ASSERT(tp->t_inpcb);
if (TCPS_HAVERCVDSYN(tp->t_state)) {
tp->t_state = TCPS_CLOSED;
(void) tcp_output_reset(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 */
INP_WLOCK_ASSERT(inp);
/*
* Make sure that all of our timers are stopped before we delete the
* PCB.
*
* XXXRW: Really, we would like to use callout_drain() here in order
* to avoid races experienced in tcp_timer.c where a timer is already
* executing at this point. However, we can't, both because we're
* running in a context where we can't sleep, and also because we
* hold locks required by the timers. What we instead need to do is
* test to see if callout_drain() is required, and if so, defer some
* portion of the remainder of tcp_discardcb() to an asynchronous
* context that can callout_drain() and then continue. Some care
* will be required to ensure that no further processing takes place
* on the tcpcb, even though it hasn't been freed (a flag?).
*/
callout_stop(&tp->t_timers->tt_rexmt);
callout_stop(&tp->t_timers->tt_persist);
callout_stop(&tp->t_timers->tt_keep);
callout_stop(&tp->t_timers->tt_2msl);
callout_stop(&tp->t_timers->tt_delack);
/*
* 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;
u_long 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 occured 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 *= (u_long)(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);
/* Disconnect offload device, if any. */
tcp_offload_detach(tp);
tcp_free_sackholes(tp);
/* Allow the CC algorithm to clean up after itself. */
if (CC_ALGO(tp)->cb_destroy != NULL)
CC_ALGO(tp)->cb_destroy(tp->ccv);
khelp_destroy_osd(tp->osd);
CC_ALGO(tp) = NULL;
inp->inp_ppcb = NULL;
tp->t_inpcb = NULL;
uma_zfree(V_tcpcb_zone, tp);
}
/*
* 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_WLOCK_ASSERT(&V_tcbinfo);
INP_WLOCK_ASSERT(inp);
/* Notify any offload devices of listener close */
if (tp->t_state == TCPS_LISTEN)
tcp_offload_listen_close(tp);
in_pcbdrop(inp);
TCPSTAT_INC(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);
ACCEPT_LOCK();
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
* usefull.
*/
INP_INFO_RLOCK(&V_tcbinfo);
LIST_FOREACH(inpb, V_tcbinfo.ipi_listhead, inp_list) {
if (inpb->inp_flags & INP_TIMEWAIT)
continue;
INP_WLOCK(inpb);
if ((tcpb = intotcpcb(inpb)) != NULL) {
tcp_reass_flush(tcpb);
tcp_clean_sackreport(tcpb);
}
INP_WUNLOCK(inpb);
}
INP_INFO_RUNLOCK(&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_WLOCK_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)) {
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)
{
int error, i, m, n, pcb_count;
struct inpcb *inp, **inp_list;
inp_gen_t gencnt;
struct xinpgen xig;
/*
* The process of preparing the TCB list is too time-consuming and
* resource-intensive to repeat twice on every request.
*/
if (req->oldptr == NULL) {
n = V_tcbinfo.ipi_count + syncache_pcbcount();
n += imax(n / 8, 10);
req->oldidx = 2 * (sizeof xig) + n * sizeof(struct xtcpcb);
return (0);
}
if (req->newptr != NULL)
return (EPERM);
/*
* OK, now we're committed to doing something.
*/
INP_INFO_RLOCK(&V_tcbinfo);
gencnt = V_tcbinfo.ipi_gencnt;
n = V_tcbinfo.ipi_count;
INP_INFO_RUNLOCK(&V_tcbinfo);
m = syncache_pcbcount();
error = sysctl_wire_old_buffer(req, 2 * (sizeof xig)
+ (n + m) * sizeof(struct xtcpcb));
if (error != 0)
return (error);
xig.xig_len = sizeof xig;
xig.xig_count = n + m;
xig.xig_gen = gencnt;
xig.xig_sogen = so_gencnt;
error = SYSCTL_OUT(req, &xig, sizeof xig);
if (error)
return (error);
error = syncache_pcblist(req, m, &pcb_count);
if (error)
return (error);
inp_list = malloc(n * sizeof *inp_list, M_TEMP, M_WAITOK);
if (inp_list == NULL)
return (ENOMEM);
INP_INFO_RLOCK(&V_tcbinfo);
for (inp = LIST_FIRST(V_tcbinfo.ipi_listhead), i = 0;
inp != NULL && i < n; inp = LIST_NEXT(inp, inp_list)) {
INP_WLOCK(inp);
if (inp->inp_gencnt <= gencnt) {
/*
* 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)
error = cr_cansee(req->td->td_ucred,
intotw(inp)->tw_cred);
else
error = EINVAL; /* Skip this inp. */
} else
error = cr_canseeinpcb(req->td->td_ucred, inp);
if (error == 0) {
in_pcbref(inp);
inp_list[i++] = inp;
}
}
INP_WUNLOCK(inp);
}
INP_INFO_RUNLOCK(&V_tcbinfo);
n = i;
error = 0;
for (i = 0; i < n; i++) {
inp = inp_list[i];
INP_RLOCK(inp);
if (inp->inp_gencnt <= gencnt) {
struct xtcpcb xt;
void *inp_ppcb;
bzero(&xt, sizeof(xt));
xt.xt_len = sizeof xt;
/* XXX should avoid extra copy */
bcopy(inp, &xt.xt_inp, sizeof *inp);
inp_ppcb = inp->inp_ppcb;
if (inp_ppcb == NULL)
bzero((char *) &xt.xt_tp, sizeof xt.xt_tp);
else if (inp->inp_flags & INP_TIMEWAIT) {
bzero((char *) &xt.xt_tp, sizeof xt.xt_tp);
xt.xt_tp.t_state = TCPS_TIME_WAIT;
} else {
bcopy(inp_ppcb, &xt.xt_tp, sizeof xt.xt_tp);
if (xt.xt_tp.t_timers)
tcp_timer_to_xtimer(&xt.xt_tp, xt.xt_tp.t_timers, &xt.xt_timer);
}
if (inp->inp_socket != NULL)
sotoxsocket(inp->inp_socket, &xt.xt_socket);
else {
bzero(&xt.xt_socket, sizeof xt.xt_socket);
xt.xt_socket.xso_protocol = IPPROTO_TCP;
}
xt.xt_inp.inp_gencnt = inp->inp_gencnt;
INP_RUNLOCK(inp);
error = SYSCTL_OUT(req, &xt, sizeof xt);
} else
INP_RUNLOCK(inp);
}
INP_INFO_WLOCK(&V_tcbinfo);
for (i = 0; i < n; i++) {
inp = inp_list[i];
INP_RLOCK(inp);
if (!in_pcbrele_rlocked(inp))
INP_RUNLOCK(inp);
}
INP_INFO_WUNLOCK(&V_tcbinfo);
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.
*/
INP_INFO_RLOCK(&V_tcbinfo);
xig.xig_gen = V_tcbinfo.ipi_gencnt;
xig.xig_sogen = so_gencnt;
xig.xig_count = V_tcbinfo.ipi_count + pcb_count;
INP_INFO_RUNLOCK(&V_tcbinfo);
error = SYSCTL_OUT(req, &xig, sizeof xig);
}
free(inp_list, M_TEMP);
return (error);
}
SYSCTL_PROC(_net_inet_tcp, TCPCTL_PCBLIST, pcblist,
CTLTYPE_OPAQUE | CTLFLAG_RD, 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 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);
inp = in_pcblookup(&V_tcbinfo, addrs[1].sin_addr, addrs[1].sin_port,
addrs[0].sin_addr, addrs[0].sin_port, INPLOOKUP_RLOCKPCB, NULL);
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, 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 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);
}
#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);
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, 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_TIMXCEED_INTRANS) && ip)
notify = tcp_drop_syn_sent;
/*
* Redirects don't need to be handled up here.
*/
else if (PRC_IS_REDIRECT(cmd))
return;
/*
* Source quench is depreciated.
*/
else if (cmd == PRC_QUENCH)
return;
/*
* 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) {
icp = (struct icmp *)((caddr_t)ip
- offsetof(struct icmp, icmp_ip));
th = (struct tcphdr *)((caddr_t)ip
+ (ip->ip_hl << 2));
INP_INFO_WLOCK(&V_tcbinfo);
inp = in_pcblookup(&V_tcbinfo, faddr, th->th_dport,
ip->ip_src, th->th_sport, INPLOOKUP_WLOCKPCB, NULL);
if (inp != NULL) {
if (!(inp->inp_flags & INP_TIMEWAIT) &&
!(inp->inp_flags & INP_DROPPED) &&
!(inp->inp_socket == NULL)) {
icmp_tcp_seq = htonl(th->th_seq);
tp = intotcpcb(inp);
if (SEQ_GEQ(icmp_tcp_seq, tp->snd_una) &&
SEQ_LT(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.
*/
bzero(&inc, sizeof(inc));
inc.inc_faddr = faddr;
inc.inc_fibnum =
inp->inp_inc.inc_fibnum;
mtu = ntohs(icp->icmp_nextmtu);
/*
* If no alternative MTU was
* proposed, try the next smaller
* one. ip->ip_len has already
* been swapped in icmp_input().
*/
if (!mtu)
mtu = ip_next_mtu(ip->ip_len,
1);
if (mtu < V_tcp_minmss
+ sizeof(struct tcpiphdr))
mtu = V_tcp_minmss
+ sizeof(struct tcpiphdr);
/*
* Only cache the MTU if it
* is smaller than the interface
* or route MTU. tcp_mtudisc()
* will do right thing by itself.
*/
if (mtu <= tcp_maxmtu(&inc, NULL))
tcp_hc_updatemtu(&inc, mtu);
tcp_mtudisc(inp, mtu);
} else
inp = (*notify)(inp,
inetctlerrmap[cmd]);
}
}
if (inp != NULL)
INP_WUNLOCK(inp);
} 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, th);
}
INP_INFO_WUNLOCK(&V_tcbinfo);
} else
in_pcbnotifyall(&V_tcbinfo, faddr, inetctlerrmap[cmd], notify);
}
#endif /* INET */
#ifdef INET6
void
tcp6_ctlinput(int cmd, struct sockaddr *sa, void *d)
{
struct tcphdr th;
struct inpcb *(*notify)(struct inpcb *, int) = tcp_notify;
struct ip6_hdr *ip6;
struct mbuf *m;
struct ip6ctlparam *ip6cp = NULL;
const struct sockaddr_in6 *sa6_src = NULL;
int off;
struct tcp_portonly {
u_int16_t th_sport;
u_int16_t th_dport;
} *thp;
if (sa->sa_family != AF_INET6 ||
sa->sa_len != sizeof(struct sockaddr_in6))
return;
if (cmd == PRC_MSGSIZE)
notify = tcp_mtudisc_notify;
else if (!PRC_IS_REDIRECT(cmd) &&
((unsigned)cmd >= PRC_NCMDS || inet6ctlerrmap[cmd] == 0))
return;
/* Source quench is depreciated. */
else if (cmd == PRC_QUENCH)
return;
/* if the parameter is from icmp6, decode it. */
if (d != NULL) {
ip6cp = (struct ip6ctlparam *)d;
m = ip6cp->ip6c_m;
ip6 = ip6cp->ip6c_ip6;
off = ip6cp->ip6c_off;
sa6_src = ip6cp->ip6c_src;
} else {
m = NULL;
ip6 = NULL;
off = 0; /* fool gcc */
sa6_src = &sa6_any;
}
if (ip6 != NULL) {
struct in_conninfo inc;
/*
* XXX: We assume that when IPV6 is non NULL,
* M and OFF are valid.
*/
/* check if we can safely examine src and dst ports */
if (m->m_pkthdr.len < off + sizeof(*thp))
return;
bzero(&th, sizeof(th));
m_copydata(m, off, sizeof(*thp), (caddr_t)&th);
in6_pcbnotify(&V_tcbinfo, sa, th.th_dport,
(struct sockaddr *)ip6cp->ip6c_src,
th.th_sport, cmd, NULL, notify);
bzero(&inc, sizeof(inc));
inc.inc_fport = th.th_dport;
inc.inc_lport = th.th_sport;
inc.inc6_faddr = ((struct sockaddr_in6 *)sa)->sin6_addr;
inc.inc6_laddr = ip6cp->ip6c_src->sin6_addr;
inc.inc_flags |= INC_ISIPV6;
INP_INFO_WLOCK(&V_tcbinfo);
syncache_unreach(&inc, &th);
INP_INFO_WUNLOCK(&V_tcbinfo);
} else
in6_pcbnotify(&V_tcbinfo, sa, 0, (const struct sockaddr *)sa6_src,
0, cmd, NULL, notify);
}
#endif /* INET6 */
/*
* 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 TCP pcbinfo 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)
static VNET_DEFINE(u_char, isn_secret[32]);
static VNET_DEFINE(int, isn_last);
static VNET_DEFINE(int, isn_last_reseed);
static VNET_DEFINE(u_int32_t, isn_offset);
static VNET_DEFINE(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 tcpcb *tp)
{
MD5_CTX isn_ctx;
u_int32_t md5_buffer[4];
tcp_seq new_isn;
u_int32_t projected_offset;
INP_WLOCK_ASSERT(tp->t_inpcb);
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))) {
read_random(&V_isn_secret, sizeof(V_isn_secret));
V_isn_last_reseed = ticks;
}
/* Compute the md5 hash and return the ISN. */
MD5Init(&isn_ctx);
MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_fport, sizeof(u_short));
MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_lport, sizeof(u_short));
#ifdef INET6
if ((tp->t_inpcb->inp_vflag & INP_IPV6) != 0) {
MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->in6p_faddr,
sizeof(struct in6_addr));
MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->in6p_laddr,
sizeof(struct in6_addr));
} else
#endif
{
MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_faddr,
sizeof(struct in_addr));
MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_laddr,
sizeof(struct in_addr));
}
MD5Update(&isn_ctx, (u_char *) &V_isn_secret, sizeof(V_isn_secret));
MD5Final((u_char *) &md5_buffer, &isn_ctx);
new_isn = (tcp_seq) md5_buffer[0];
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;
INP_INFO_WLOCK_ASSERT(&V_tcbinfo);
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);
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)
{
return (tcp_mtudisc(inp, -1));
}
struct inpcb *
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 (inp);
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);
tcp_output_send(tp);
return (inp);
}
#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.
*/
u_long
tcp_maxmtu(struct in_conninfo *inc, int *flags)
{
struct route sro;
struct sockaddr_in *dst;
struct ifnet *ifp;
u_long maxmtu = 0;
KASSERT(inc != NULL, ("tcp_maxmtu with NULL in_conninfo pointer"));
bzero(&sro, sizeof(sro));
if (inc->inc_faddr.s_addr != INADDR_ANY) {
dst = (struct sockaddr_in *)&sro.ro_dst;
dst->sin_family = AF_INET;
dst->sin_len = sizeof(*dst);
dst->sin_addr = inc->inc_faddr;
in_rtalloc_ign(&sro, 0, inc->inc_fibnum);
}
if (sro.ro_rt != NULL) {
ifp = sro.ro_rt->rt_ifp;
if (sro.ro_rt->rt_rmx.rmx_mtu == 0)
maxmtu = ifp->if_mtu;
else
maxmtu = min(sro.ro_rt->rt_rmx.rmx_mtu, ifp->if_mtu);
/* Report additional interface capabilities. */
if (flags != NULL) {
if (ifp->if_capenable & IFCAP_TSO4 &&
ifp->if_hwassist & CSUM_TSO)
*flags |= CSUM_TSO;
}
RTFREE(sro.ro_rt);
}
return (maxmtu);
}
#endif /* INET */
#ifdef INET6
u_long
tcp_maxmtu6(struct in_conninfo *inc, int *flags)
{
struct route_in6 sro6;
struct ifnet *ifp;
u_long maxmtu = 0;
KASSERT(inc != NULL, ("tcp_maxmtu6 with NULL in_conninfo pointer"));
bzero(&sro6, sizeof(sro6));
if (!IN6_IS_ADDR_UNSPECIFIED(&inc->inc6_faddr)) {
sro6.ro_dst.sin6_family = AF_INET6;
sro6.ro_dst.sin6_len = sizeof(struct sockaddr_in6);
sro6.ro_dst.sin6_addr = inc->inc6_faddr;
in6_rtalloc_ign(&sro6, 0, inc->inc_fibnum);
}
if (sro6.ro_rt != NULL) {
ifp = sro6.ro_rt->rt_ifp;
if (sro6.ro_rt->rt_rmx.rmx_mtu == 0)
maxmtu = IN6_LINKMTU(sro6.ro_rt->rt_ifp);
else
maxmtu = min(sro6.ro_rt->rt_rmx.rmx_mtu,
IN6_LINKMTU(sro6.ro_rt->rt_ifp));
/* Report additional interface capabilities. */
if (flags != NULL) {
if (ifp->if_capenable & IFCAP_TSO6 &&
ifp->if_hwassist & CSUM_TSO)
*flags |= CSUM_TSO;
}
RTFREE(sro6.ro_rt);
}
return (maxmtu);
}
#endif /* INET6 */
#ifdef IPSEC
/* compute ESP/AH header size for TCP, including outer IP header. */
size_t
ipsec_hdrsiz_tcp(struct tcpcb *tp)
{
struct inpcb *inp;
struct mbuf *m;
size_t hdrsiz;
struct ip *ip;
#ifdef INET6
struct ip6_hdr *ip6;
#endif
struct tcphdr *th;
if ((tp == NULL) || ((inp = tp->t_inpcb) == NULL))
return (0);
MGETHDR(m, M_DONTWAIT, MT_DATA);
if (!m)
return (0);
#ifdef INET6
if ((inp->inp_vflag & INP_IPV6) != 0) {
ip6 = mtod(m, struct ip6_hdr *);
th = (struct tcphdr *)(ip6 + 1);
m->m_pkthdr.len = m->m_len =
sizeof(struct ip6_hdr) + sizeof(struct tcphdr);
tcpip_fillheaders(inp, ip6, th);
hdrsiz = ipsec_hdrsiz(m, IPSEC_DIR_OUTBOUND, inp);
} else
#endif /* INET6 */
{
ip = mtod(m, struct ip *);
th = (struct tcphdr *)(ip + 1);
m->m_pkthdr.len = m->m_len = sizeof(struct tcpiphdr);
tcpip_fillheaders(inp, ip, th);
hdrsiz = ipsec_hdrsiz(m, IPSEC_DIR_OUTBOUND, inp);
}
m_free(m);
return (hdrsiz);
}
#endif /* IPSEC */
#ifdef TCP_SIGNATURE
/*
* Callback function invoked by m_apply() to digest TCP segment data
* contained within an mbuf chain.
*/
static int
tcp_signature_apply(void *fstate, void *data, u_int len)
{
MD5Update(fstate, (u_char *)data, len);
return (0);
}
/*
* Compute TCP-MD5 hash of a TCP segment. (RFC2385)
*
* Parameters:
* m pointer to head of mbuf chain
* _unused
* len length of TCP segment data, excluding options
* optlen length of TCP segment options
* buf pointer to storage for computed MD5 digest
* direction direction of flow (IPSEC_DIR_INBOUND or OUTBOUND)
*
* We do this over ip, tcphdr, segment data, and the key in the SADB.
* When called from tcp_input(), we can be sure that th_sum has been
* zeroed out and verified already.
*
* Return 0 if successful, otherwise return -1.
*
* XXX The key is retrieved from the system's PF_KEY SADB, by keying a
* search with the destination IP address, and a 'magic SPI' to be
* determined by the application. This is hardcoded elsewhere to 1179
* right now. Another branch of this code exists which uses the SPD to
* specify per-application flows but it is unstable.
*/
int
tcp_signature_compute(struct mbuf *m, int _unused, int len, int optlen,
u_char *buf, u_int direction)
{
union sockaddr_union dst;
#ifdef INET
struct ippseudo ippseudo;
#endif
MD5_CTX ctx;
int doff;
struct ip *ip;
#ifdef INET
struct ipovly *ipovly;
#endif
struct secasvar *sav;
struct tcphdr *th;
#ifdef INET6
struct ip6_hdr *ip6;
struct in6_addr in6;
char ip6buf[INET6_ADDRSTRLEN];
uint32_t plen;
uint16_t nhdr;
#endif
u_short savecsum;
KASSERT(m != NULL, ("NULL mbuf chain"));
KASSERT(buf != NULL, ("NULL signature pointer"));
/* Extract the destination from the IP header in the mbuf. */
bzero(&dst, sizeof(union sockaddr_union));
ip = mtod(m, struct ip *);
#ifdef INET6
ip6 = NULL; /* Make the compiler happy. */
#endif
switch (ip->ip_v) {
#ifdef INET
case IPVERSION:
dst.sa.sa_len = sizeof(struct sockaddr_in);
dst.sa.sa_family = AF_INET;
dst.sin.sin_addr = (direction == IPSEC_DIR_INBOUND) ?
ip->ip_src : ip->ip_dst;
break;
#endif
#ifdef INET6
case (IPV6_VERSION >> 4):
ip6 = mtod(m, struct ip6_hdr *);
dst.sa.sa_len = sizeof(struct sockaddr_in6);
dst.sa.sa_family = AF_INET6;
dst.sin6.sin6_addr = (direction == IPSEC_DIR_INBOUND) ?
ip6->ip6_src : ip6->ip6_dst;
break;
#endif
default:
return (EINVAL);
/* NOTREACHED */
break;
}
/* Look up an SADB entry which matches the address of the peer. */
sav = KEY_ALLOCSA(&dst, IPPROTO_TCP, htonl(TCP_SIG_SPI));
if (sav == NULL) {
ipseclog((LOG_ERR, "%s: SADB lookup failed for %s\n", __func__,
(ip->ip_v == IPVERSION) ? inet_ntoa(dst.sin.sin_addr) :
#ifdef INET6
(ip->ip_v == (IPV6_VERSION >> 4)) ?
ip6_sprintf(ip6buf, &dst.sin6.sin6_addr) :
#endif
"(unsupported)"));
return (EINVAL);
}
MD5Init(&ctx);
/*
* Step 1: Update MD5 hash with IP(v6) pseudo-header.
*
* XXX The ippseudo header MUST be digested in network byte order,
* or else we'll fail the regression test. Assume all fields we've
* been doing arithmetic on have been in host byte order.
* XXX One cannot depend on ipovly->ih_len here. When called from
* tcp_output(), the underlying ip_len member has not yet been set.
*/
switch (ip->ip_v) {
#ifdef INET
case IPVERSION:
ipovly = (struct ipovly *)ip;
ippseudo.ippseudo_src = ipovly->ih_src;
ippseudo.ippseudo_dst = ipovly->ih_dst;
ippseudo.ippseudo_pad = 0;
ippseudo.ippseudo_p = IPPROTO_TCP;
ippseudo.ippseudo_len = htons(len + sizeof(struct tcphdr) +
optlen);
MD5Update(&ctx, (char *)&ippseudo, sizeof(struct ippseudo));
th = (struct tcphdr *)((u_char *)ip + sizeof(struct ip));
doff = sizeof(struct ip) + sizeof(struct tcphdr) + optlen;
break;
#endif
#ifdef INET6
/*
* RFC 2385, 2.0 Proposal
* For IPv6, the pseudo-header is as described in RFC 2460, namely the
* 128-bit source IPv6 address, 128-bit destination IPv6 address, zero-
* extended next header value (to form 32 bits), and 32-bit segment
* length.
* Note: Upper-Layer Packet Length comes before Next Header.
*/
case (IPV6_VERSION >> 4):
in6 = ip6->ip6_src;
in6_clearscope(&in6);
MD5Update(&ctx, (char *)&in6, sizeof(struct in6_addr));
in6 = ip6->ip6_dst;
in6_clearscope(&in6);
MD5Update(&ctx, (char *)&in6, sizeof(struct in6_addr));
plen = htonl(len + sizeof(struct tcphdr) + optlen);
MD5Update(&ctx, (char *)&plen, sizeof(uint32_t));
nhdr = 0;
MD5Update(&ctx, (char *)&nhdr, sizeof(uint8_t));
MD5Update(&ctx, (char *)&nhdr, sizeof(uint8_t));
MD5Update(&ctx, (char *)&nhdr, sizeof(uint8_t));
nhdr = IPPROTO_TCP;
MD5Update(&ctx, (char *)&nhdr, sizeof(uint8_t));
th = (struct tcphdr *)((u_char *)ip6 + sizeof(struct ip6_hdr));
doff = sizeof(struct ip6_hdr) + sizeof(struct tcphdr) + optlen;
break;
#endif
default:
return (EINVAL);
/* NOTREACHED */
break;
}
/*
* Step 2: Update MD5 hash with TCP header, excluding options.
* The TCP checksum must be set to zero.
*/
savecsum = th->th_sum;
th->th_sum = 0;
MD5Update(&ctx, (char *)th, sizeof(struct tcphdr));
th->th_sum = savecsum;
/*
* Step 3: Update MD5 hash with TCP segment data.
* Use m_apply() to avoid an early m_pullup().
*/
if (len > 0)
m_apply(m, doff, len, tcp_signature_apply, &ctx);
/*
* Step 4: Update MD5 hash with shared secret.
*/
MD5Update(&ctx, sav->key_auth->key_data, _KEYLEN(sav->key_auth));
MD5Final(buf, &ctx);
key_sa_recordxfer(sav, m);
KEY_FREESAV(&sav);
return (0);
}
/*
* Verify the TCP-MD5 hash of a TCP segment. (RFC2385)
*
* Parameters:
* m pointer to head of mbuf chain
* len length of TCP segment data, excluding options
* optlen length of TCP segment options
* buf pointer to storage for computed MD5 digest
* direction direction of flow (IPSEC_DIR_INBOUND or OUTBOUND)
*
* Return 1 if successful, otherwise return 0.
*/
int
tcp_signature_verify(struct mbuf *m, int off0, int tlen, int optlen,
struct tcpopt *to, struct tcphdr *th, u_int tcpbflag)
{
char tmpdigest[TCP_SIGLEN];
if (tcp_sig_checksigs == 0)
return (1);
if ((tcpbflag & TF_SIGNATURE) == 0) {
if ((to->to_flags & TOF_SIGNATURE) != 0) {
/*
* If this socket is not expecting signature but
* the segment contains signature just fail.
*/
TCPSTAT_INC(tcps_sig_err_sigopt);
TCPSTAT_INC(tcps_sig_rcvbadsig);
return (0);
}
/* Signature is not expected, and not present in segment. */
return (1);
}
/*
* If this socket is expecting signature but the segment does not
* contain any just fail.
*/
if ((to->to_flags & TOF_SIGNATURE) == 0) {
TCPSTAT_INC(tcps_sig_err_nosigopt);
TCPSTAT_INC(tcps_sig_rcvbadsig);
return (0);
}
if (tcp_signature_compute(m, off0, tlen, optlen, &tmpdigest[0],
IPSEC_DIR_INBOUND) == -1) {
TCPSTAT_INC(tcps_sig_err_buildsig);
TCPSTAT_INC(tcps_sig_rcvbadsig);
return (0);
}
if (bcmp(to->to_signature, &tmpdigest[0], TCP_SIGLEN) != 0) {
TCPSTAT_INC(tcps_sig_rcvbadsig);
return (0);
}
TCPSTAT_INC(tcps_sig_rcvgoodsig);
return (1);
}
#endif /* TCP_SIGNATURE */
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;
#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);
}
INP_INFO_WLOCK(&V_tcbinfo);
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;
INP_INFO_WUNLOCK(&V_tcbinfo);
return (error);
}
SYSCTL_VNET_PROC(_net_inet_tcp, TCPCTL_DROP, drop,
CTLTYPE_STRUCT|CTLFLAG_WR|CTLFLAG_SKIP, NULL,
0, sysctl_drop, "", "Drop TCP connection");
/*
* 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 (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);
}
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