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freebsd-skq/sys/netinet/tcp_subr.c
Lawrence Stewart 24cb0f2232 Add TCP Appropriate Byte Counting (RFC 3465) support to kernel. 
The new behaviour is on by default, and can be disabled by setting the
net.inet.tcp.rfc3465 sysctl to 0 to obtain previous behaviour.

The patch changes struct tcpcb in sys/netinet/tcp_var.h which breaks
the ABI. Bump __FreeBSD_version to 800061 accordingly. User space tools
that rely on the size of struct tcpcb (e.g. sockstat) need to be recompiled.

Reviewed by:	rpaulo, gnn
Approved by:	gnn, kmacy (mentors)
Sponsored by:	FreeBSD Foundation
2009-01-15 06:44:22 +00:00

2311 lines
64 KiB
C
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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_mac.h"
#include "opt_tcpdebug.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/callout.h>
#include <sys/kernel.h>
#include <sys/sysctl.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 <sys/vimage.h>
#include <vm/uma.h>
#include <net/route.h>
#include <net/if.h>
#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#ifdef INET6
#include <netinet/ip6.h>
#endif
#include <netinet/in_pcb.h>
#ifdef INET6
#include <netinet6/in6_pcb.h>
#endif
#include <netinet/in_var.h>
#include <netinet/ip_var.h>
#ifdef INET6
#include <netinet6/ip6_var.h>
#include <netinet6/scope6_var.h>
#include <netinet6/nd6.h>
#endif
#include <netinet/ip_icmp.h>
#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_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
#include <netinet/vinet.h>
#include <netinet6/ip6protosw.h>
#include <netinet6/vinet6.h>
#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>
#ifdef VIMAGE_GLOBALS
int tcp_mssdflt;
#ifdef INET6
int tcp_v6mssdflt;
#endif
int tcp_minmss;
int tcp_do_rfc1323;
static int icmp_may_rst;
static int tcp_isn_reseed_interval;
static int tcp_inflight_enable;
static int tcp_inflight_rttthresh;
static int tcp_inflight_min;
static int tcp_inflight_max;
static int tcp_inflight_stab;
#endif
static int
sysctl_net_inet_tcp_mss_check(SYSCTL_HANDLER_ARGS)
{
INIT_VNET_INET(curvnet);
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_V_PROC(V_NET, vnet_inet, _net_inet_tcp, TCPCTL_MSSDFLT, mssdflt,
CTLTYPE_INT|CTLFLAG_RW, 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)
{
INIT_VNET_INET(curvnet);
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_V_PROC(V_NET, vnet_inet, _net_inet_tcp, TCPCTL_V6MSSDFLT, v6mssdflt,
CTLTYPE_INT|CTLFLAG_RW, tcp_v6mssdflt, 0,
&sysctl_net_inet_tcp_mss_v6_check, "I",
"Default TCP Maximum Segment Size for IPv6");
#endif
/*
* 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.
*/
SYSCTL_V_INT(V_NET, vnet_inet, _net_inet_tcp, OID_AUTO, minmss,
CTLFLAG_RW, tcp_minmss , 0, "Minmum TCP Maximum Segment Size");
SYSCTL_V_INT(V_NET, vnet_inet, _net_inet_tcp, TCPCTL_DO_RFC1323, rfc1323,
CTLFLAG_RW, 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_V_INT(V_NET, vnet_inet, _net_inet_tcp, OID_AUTO, pcbcount,
CTLFLAG_RD, tcbinfo.ipi_count, 0, "Number of active PCBs");
SYSCTL_V_INT(V_NET, vnet_inet, _net_inet_tcp, OID_AUTO, icmp_may_rst,
CTLFLAG_RW, icmp_may_rst, 0,
"Certain ICMP unreachable messages may abort connections in SYN_SENT");
SYSCTL_V_INT(V_NET, vnet_inet, _net_inet_tcp, OID_AUTO, isn_reseed_interval,
CTLFLAG_RW, tcp_isn_reseed_interval, 0,
"Seconds between reseeding of ISN secret");
/*
* TCP bandwidth limiting sysctls. Note that the default lower bound of
* 1024 exists only for debugging. A good production default would be
* something like 6100.
*/
SYSCTL_NODE(_net_inet_tcp, OID_AUTO, inflight, CTLFLAG_RW, 0,
"TCP inflight data limiting");
SYSCTL_V_INT(V_NET, vnet_inet, _net_inet_tcp_inflight, OID_AUTO, enable,
CTLFLAG_RW, tcp_inflight_enable, 0,
"Enable automatic TCP inflight data limiting");
static int tcp_inflight_debug = 0;
SYSCTL_INT(_net_inet_tcp_inflight, OID_AUTO, debug, CTLFLAG_RW,
&tcp_inflight_debug, 0, "Debug TCP inflight calculations");
SYSCTL_V_PROC(V_NET, vnet_inet, _net_inet_tcp_inflight, OID_AUTO, rttthresh,
CTLTYPE_INT|CTLFLAG_RW, tcp_inflight_rttthresh, 0, sysctl_msec_to_ticks,
"I", "RTT threshold below which inflight will deactivate itself");
SYSCTL_V_INT(V_NET, vnet_inet, _net_inet_tcp_inflight, OID_AUTO, min,
CTLFLAG_RW, tcp_inflight_min, 0, "Lower-bound for TCP inflight window");
SYSCTL_V_INT(V_NET, vnet_inet, _net_inet_tcp_inflight, OID_AUTO, max,
CTLFLAG_RW, tcp_inflight_max, 0, "Upper-bound for TCP inflight window");
SYSCTL_V_INT(V_NET, vnet_inet, _net_inet_tcp_inflight, OID_AUTO, stab,
CTLFLAG_RW, tcp_inflight_stab, 0,
"Inflight Algorithm Stabilization 20 = 2 packets");
uma_zone_t sack_hole_zone;
static struct inpcb *tcp_notify(struct inpcb *, int);
static void tcp_isn_tick(void *);
/*
* 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;
};
static uma_zone_t tcpcb_zone;
MALLOC_DEFINE(M_TCPLOG, "tcplog", "TCP address and flags print buffers");
struct callout isn_callout;
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(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)
{
INIT_VNET_INET(curvnet);
int hashsize;
V_blackhole = 0;
V_tcp_delack_enabled = 1;
V_drop_synfin = 0;
V_tcp_do_rfc3042 = 1;
V_tcp_do_rfc3390 = 1;
V_tcp_do_ecn = 0;
V_tcp_ecn_maxretries = 1;
V_tcp_insecure_rst = 0;
V_tcp_do_autorcvbuf = 1;
V_tcp_autorcvbuf_inc = 16*1024;
V_tcp_autorcvbuf_max = 256*1024;
V_tcp_do_rfc3465 = 1;
V_tcp_abc_l_var = 2;
V_tcp_mssdflt = TCP_MSS;
#ifdef INET6
V_tcp_v6mssdflt = TCP6_MSS;
#endif
V_tcp_minmss = TCP_MINMSS;
V_tcp_do_rfc1323 = 1;
V_icmp_may_rst = 1;
V_tcp_isn_reseed_interval = 0;
V_tcp_inflight_enable = 1;
V_tcp_inflight_min = 6144;
V_tcp_inflight_max = TCP_MAXWIN << TCP_MAX_WINSHIFT;
V_tcp_inflight_stab = 20;
V_path_mtu_discovery = 1;
V_ss_fltsz = 1;
V_ss_fltsz_local = 4;
V_tcp_do_newreno = 1;
V_tcp_do_tso = 1;
V_tcp_do_autosndbuf = 1;
V_tcp_autosndbuf_inc = 8*1024;
V_tcp_autosndbuf_max = 256*1024;
V_nolocaltimewait = 0;
V_tcp_do_sack = 1;
V_tcp_sack_maxholes = 128;
V_tcp_sack_globalmaxholes = 65536;
V_tcp_sack_globalholes = 0;
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;
V_tcp_inflight_rttthresh = TCPTV_INFLIGHT_RTTTHRESH;
tcp_finwait2_timeout = TCPTV_FINWAIT2_TIMEOUT;
TUNABLE_INT_FETCH("net.inet.tcp.sack.enable", &V_tcp_do_sack);
INP_INFO_LOCK_INIT(&V_tcbinfo, "tcp");
LIST_INIT(&V_tcb);
V_tcbinfo.ipi_listhead = &V_tcb;
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 */
}
tcp_tcbhashsize = hashsize;
V_tcbinfo.ipi_hashbase = hashinit(hashsize, M_PCB,
&V_tcbinfo.ipi_hashmask);
V_tcbinfo.ipi_porthashbase = hashinit(hashsize, M_PCB,
&V_tcbinfo.ipi_porthashmask);
V_tcbinfo.ipi_zone = uma_zcreate("inpcb", sizeof(struct inpcb),
NULL, NULL, tcp_inpcb_init, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE);
uma_zone_set_max(V_tcbinfo.ipi_zone, maxsockets);
#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
/*
* These have to be type stable for the benefit of the timers.
*/
tcpcb_zone = uma_zcreate("tcpcb", sizeof(struct tcpcb_mem),
NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE);
uma_zone_set_max(tcpcb_zone, maxsockets);
tcp_tw_init();
syncache_init();
tcp_hc_init();
tcp_reass_init();
ISN_LOCK_INIT();
callout_init(&isn_callout, CALLOUT_MPSAFE);
tcp_isn_tick(NULL);
EVENTHANDLER_REGISTER(shutdown_pre_sync, tcp_fini, NULL,
SHUTDOWN_PRI_DEFAULT);
sack_hole_zone = uma_zcreate("sackhole", sizeof(struct sackhole),
NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE);
EVENTHANDLER_REGISTER(maxsockets_change, tcp_zone_change, NULL,
EVENTHANDLER_PRI_ANY);
}
void
tcp_fini(void *xtp)
{
callout_stop(&isn_callout);
}
/*
* 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;
} else
#endif
{
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;
}
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)
{
INIT_VNET_INET(curvnet);
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 == 6;
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_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, n_long);
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, n_short);
#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);
} else
#endif
{
tlen += sizeof (struct tcpiphdr);
ip->ip_len = tlen;
ip->ip_ttl = V_ip_defttl;
if (V_path_mtu_discovery)
ip->ip_off |= IP_DF;
}
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);
} else
#endif /* INET6 */
{
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);
}
#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);
else
#endif /* INET6 */
(void) ip_output(m, NULL, NULL, ipflags, NULL, inp);
}
/*
* 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)
{
INIT_VNET_INET(inp->inp_vnet);
struct tcpcb_mem *tm;
struct tcpcb *tp;
#ifdef INET6
int isipv6 = (inp->inp_vflag & INP_IPV6) != 0;
#endif /* INET6 */
tm = uma_zalloc(tcpcb_zone, M_NOWAIT | M_ZERO);
if (tm == NULL)
return (NULL);
tp = &tm->tcb;
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_bwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT;
tp->snd_ssthresh = TCP_MAXWIN << TCP_MAX_WINSHIFT;
tp->t_rcvtime = ticks;
tp->t_bw_rtttime = 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 */
}
/*
* 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)
{
INIT_VNET_INET(tp->t_inpcb->inp_vnet);
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);
V_tcpstat.tcps_drops++;
} else
V_tcpstat.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)
{
INIT_VNET_INET(tp->t_vnet);
struct tseg_qent *q;
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.
*/
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;
/* XXX: This wraps if the pipe is more than 4 Gbit per second */
metrics.rmx_bandwidth = tp->snd_bandwidth;
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 */
while ((q = LIST_FIRST(&tp->t_segq)) != NULL) {
LIST_REMOVE(q, tqe_q);
m_freem(q->tqe_m);
uma_zfree(tcp_reass_zone, q);
tp->t_segqlen--;
V_tcp_reass_qsize--;
}
/* Disconnect offload device, if any. */
tcp_offload_detach(tp);
tcp_free_sackholes(tp);
inp->inp_ppcb = NULL;
tp->t_inpcb = NULL;
uma_zfree(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)
{
INIT_VNET_INET(tp->t_inpcb->inp_vnet);
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);
V_tcpstat.tcps_closed++;
KASSERT(inp->inp_socket != NULL, ("tcp_close: inp_socket NULL"));
so = inp->inp_socket;
soisdisconnected(so);
if (inp->inp_vflag & INP_SOCKREF) {
KASSERT(so->so_state & SS_PROTOREF,
("tcp_close: !SS_PROTOREF"));
inp->inp_vflag &= ~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();
VNET_FOREACH(vnet_iter) {
CURVNET_SET(vnet_iter);
INIT_VNET_INET(vnet_iter);
struct inpcb *inpb;
struct tcpcb *tcpb;
struct tseg_qent *te;
/*
* 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_vflag & INP_TIMEWAIT)
continue;
INP_WLOCK(inpb);
if ((tcpb = intotcpcb(inpb)) != NULL) {
while ((te = LIST_FIRST(&tcpb->t_segq))
!= NULL) {
LIST_REMOVE(te, tqe_q);
m_freem(te->tqe_m);
uma_zfree(tcp_reass_zone, te);
tcpb->t_segqlen--;
V_tcp_reass_qsize--;
}
tcp_clean_sackreport(tcpb);
}
INP_WUNLOCK(inpb);
}
INP_INFO_RUNLOCK(&V_tcbinfo);
CURVNET_RESTORE();
}
VNET_LIST_RUNLOCK();
}
/*
* 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;
#ifdef INVARIANTS
INIT_VNET_INET(inp->inp_vnet); /* V_tcbinfo WLOCK ASSERT */
#endif
INP_INFO_WLOCK_ASSERT(&V_tcbinfo);
INP_WLOCK_ASSERT(inp);
if ((inp->inp_vflag & INP_TIMEWAIT) ||
(inp->inp_vflag & 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)
{
INIT_VNET_INET(curvnet);
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) {
m = syncache_pcbcount();
n = V_tcbinfo.ipi_count;
req->oldidx = 2 * (sizeof xig)
+ ((m + n) + n/8) * 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_RLOCK(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_vflag & 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)
inp_list[i++] = inp;
}
INP_RUNLOCK(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_vflag & 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 (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);
}
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, CTLFLAG_RD, 0, 0,
tcp_pcblist, "S,xtcpcb", "List of active TCP connections");
static int
tcp_getcred(SYSCTL_HANDLER_ARGS)
{
INIT_VNET_INET(curvnet);
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_INFO_RLOCK(&V_tcbinfo);
inp = in_pcblookup_hash(&V_tcbinfo, addrs[1].sin_addr,
addrs[1].sin_port, addrs[0].sin_addr, addrs[0].sin_port, 0, NULL);
if (inp != NULL) {
INP_RLOCK(inp);
INP_INFO_RUNLOCK(&V_tcbinfo);
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 {
INP_INFO_RUNLOCK(&V_tcbinfo);
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");
#ifdef INET6
static int
tcp6_getcred(SYSCTL_HANDLER_ARGS)
{
INIT_VNET_INET(curvnet);
INIT_VNET_INET6(curvnet);
struct xucred xuc;
struct sockaddr_in6 addrs[2];
struct inpcb *inp;
int error, mapped = 0;
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)) {
if (IN6_IS_ADDR_V4MAPPED(&addrs[1].sin6_addr))
mapped = 1;
else
return (EINVAL);
}
INP_INFO_RLOCK(&V_tcbinfo);
if (mapped == 1)
inp = in_pcblookup_hash(&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,
0, NULL);
else
inp = in6_pcblookup_hash(&V_tcbinfo,
&addrs[1].sin6_addr, addrs[1].sin6_port,
&addrs[0].sin6_addr, addrs[0].sin6_port, 0, NULL);
if (inp != NULL) {
INP_RLOCK(inp);
INP_INFO_RUNLOCK(&V_tcbinfo);
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 {
INP_INFO_RUNLOCK(&V_tcbinfo);
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
void
tcp_ctlinput(int cmd, struct sockaddr *sa, void *vip)
{
INIT_VNET_INET(curvnet);
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;
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_hash(&V_tcbinfo, faddr, th->th_dport,
ip->ip_src, th->th_sport, 0, NULL);
if (inp != NULL) {
INP_WLOCK(inp);
if (!(inp->inp_vflag & INP_TIMEWAIT) &&
!(inp->inp_vflag & 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 < max(296, V_tcp_minmss
+ sizeof(struct tcpiphdr)))
mtu = 0;
if (!mtu)
mtu = V_tcp_mssdflt
+ sizeof(struct tcpiphdr);
/*
* Only cache the 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);
}
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);
}
#ifdef INET6
void
tcp6_ctlinput(int cmd, struct sockaddr *sa, void *d)
{
INIT_VNET_INET(curvnet);
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;
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)
#ifdef VIMAGE_GLOBALS
static u_char isn_secret[32];
static int isn_last_reseed;
static u_int32_t isn_offset, isn_offset_old;
#endif
tcp_seq
tcp_new_isn(struct tcpcb *tp)
{
INIT_VNET_INET(tp->t_vnet);
MD5_CTX isn_ctx;
u_int32_t md5_buffer[4];
tcp_seq new_isn;
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);
new_isn += V_isn_offset;
ISN_UNLOCK();
return (new_isn);
}
/*
* Increment the offset to the next ISN_BYTES_PER_SECOND / 100 boundary
* to keep time flowing at a relatively constant rate. If the random
* increments have already pushed us past the projected offset, do nothing.
*/
static void
tcp_isn_tick(void *xtp)
{
VNET_ITERATOR_DECL(vnet_iter);
u_int32_t projected_offset;
ISN_LOCK();
VNET_LIST_RLOCK();
VNET_FOREACH(vnet_iter) {
CURVNET_SET(vnet_iter); /* XXX appease INVARIANTS */
INIT_VNET_INET(curvnet);
projected_offset =
V_isn_offset_old + ISN_BYTES_PER_SECOND / 100;
if (SEQ_GT(projected_offset, V_isn_offset))
V_isn_offset = projected_offset;
V_isn_offset_old = V_isn_offset;
CURVNET_RESTORE();
}
VNET_LIST_RUNLOCK();
callout_reset(&isn_callout, hz/100, tcp_isn_tick, NULL);
ISN_UNLOCK();
}
/*
* 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)
{
#ifdef INVARIANTS
INIT_VNET_INET(inp->inp_vnet);
#endif
struct tcpcb *tp;
INP_INFO_WLOCK_ASSERT(&V_tcbinfo);
INP_WLOCK_ASSERT(inp);
if ((inp->inp_vflag & INP_TIMEWAIT) ||
(inp->inp_vflag & 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 in the route. 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.
*/
struct inpcb *
tcp_mtudisc(struct inpcb *inp, int errno)
{
INIT_VNET_INET(inp->inp_vnet);
struct tcpcb *tp;
struct socket *so;
INP_WLOCK_ASSERT(inp);
if ((inp->inp_vflag & INP_TIMEWAIT) ||
(inp->inp_vflag & INP_DROPPED))
return (inp);
tp = intotcpcb(inp);
KASSERT(tp != NULL, ("tcp_mtudisc: tp == NULL"));
tcp_mss_update(tp, -1, 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);
V_tcpstat.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);
tcp_output_send(tp);
return (inp);
}
/*
* 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);
}
#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;
rtalloc_ign((struct route *)&sro6, 0);
}
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 = ipsec6_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 = ipsec4_hdrsiz(m, IPSEC_DIR_OUTBOUND, inp);
}
m_free(m);
return (hdrsiz);
}
#endif /* IPSEC */
/*
* TCP BANDWIDTH DELAY PRODUCT WINDOW LIMITING
*
* This code attempts to calculate the bandwidth-delay product as a
* means of determining the optimal window size to maximize bandwidth,
* minimize RTT, and avoid the over-allocation of buffers on interfaces and
* routers. This code also does a fairly good job keeping RTTs in check
* across slow links like modems. We implement an algorithm which is very
* similar (but not meant to be) TCP/Vegas. The code operates on the
* transmitter side of a TCP connection and so only effects the transmit
* side of the connection.
*
* BACKGROUND: TCP makes no provision for the management of buffer space
* at the end points or at the intermediate routers and switches. A TCP
* stream, whether using NewReno or not, will eventually buffer as
* many packets as it is able and the only reason this typically works is
* due to the fairly small default buffers made available for a connection
* (typicaly 16K or 32K). As machines use larger windows and/or window
* scaling it is now fairly easy for even a single TCP connection to blow-out
* all available buffer space not only on the local interface, but on
* intermediate routers and switches as well. NewReno makes a misguided
* attempt to 'solve' this problem by waiting for an actual failure to occur,
* then backing off, then steadily increasing the window again until another
* failure occurs, ad-infinitum. This results in terrible oscillation that
* is only made worse as network loads increase and the idea of intentionally
* blowing out network buffers is, frankly, a terrible way to manage network
* resources.
*
* It is far better to limit the transmit window prior to the failure
* condition being achieved. There are two general ways to do this: First
* you can 'scan' through different transmit window sizes and locate the
* point where the RTT stops increasing, indicating that you have filled the
* pipe, then scan backwards until you note that RTT stops decreasing, then
* repeat ad-infinitum. This method works in principle but has severe
* implementation issues due to RTT variances, timer granularity, and
* instability in the algorithm which can lead to many false positives and
* create oscillations as well as interact badly with other TCP streams
* implementing the same algorithm.
*
* The second method is to limit the window to the bandwidth delay product
* of the link. This is the method we implement. RTT variances and our
* own manipulation of the congestion window, bwnd, can potentially
* destabilize the algorithm. For this reason we have to stabilize the
* elements used to calculate the window. We do this by using the minimum
* observed RTT, the long term average of the observed bandwidth, and
* by adding two segments worth of slop. It isn't perfect but it is able
* to react to changing conditions and gives us a very stable basis on
* which to extend the algorithm.
*/
void
tcp_xmit_bandwidth_limit(struct tcpcb *tp, tcp_seq ack_seq)
{
INIT_VNET_INET(tp->t_vnet);
u_long bw;
u_long bwnd;
int save_ticks;
INP_WLOCK_ASSERT(tp->t_inpcb);
/*
* If inflight_enable is disabled in the middle of a tcp connection,
* make sure snd_bwnd is effectively disabled.
*/
if (V_tcp_inflight_enable == 0 ||
tp->t_rttlow < V_tcp_inflight_rttthresh) {
tp->snd_bwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT;
tp->snd_bandwidth = 0;
return;
}
/*
* Figure out the bandwidth. Due to the tick granularity this
* is a very rough number and it MUST be averaged over a fairly
* long period of time. XXX we need to take into account a link
* that is not using all available bandwidth, but for now our
* slop will ramp us up if this case occurs and the bandwidth later
* increases.
*
* Note: if ticks rollover 'bw' may wind up negative. We must
* effectively reset t_bw_rtttime for this case.
*/
save_ticks = ticks;
if ((u_int)(save_ticks - tp->t_bw_rtttime) < 1)
return;
bw = (int64_t)(ack_seq - tp->t_bw_rtseq) * hz /
(save_ticks - tp->t_bw_rtttime);
tp->t_bw_rtttime = save_ticks;
tp->t_bw_rtseq = ack_seq;
if (tp->t_bw_rtttime == 0 || (int)bw < 0)
return;
bw = ((int64_t)tp->snd_bandwidth * 15 + bw) >> 4;
tp->snd_bandwidth = bw;
/*
* Calculate the semi-static bandwidth delay product, plus two maximal
* segments. The additional slop puts us squarely in the sweet
* spot and also handles the bandwidth run-up case and stabilization.
* Without the slop we could be locking ourselves into a lower
* bandwidth.
*
* Situations Handled:
* (1) Prevents over-queueing of packets on LANs, especially on
* high speed LANs, allowing larger TCP buffers to be
* specified, and also does a good job preventing
* over-queueing of packets over choke points like modems
* (at least for the transmit side).
*
* (2) Is able to handle changing network loads (bandwidth
* drops so bwnd drops, bandwidth increases so bwnd
* increases).
*
* (3) Theoretically should stabilize in the face of multiple
* connections implementing the same algorithm (this may need
* a little work).
*
* (4) Stability value (defaults to 20 = 2 maximal packets) can
* be adjusted with a sysctl but typically only needs to be
* on very slow connections. A value no smaller then 5
* should be used, but only reduce this default if you have
* no other choice.
*/
#define USERTT ((tp->t_srtt + tp->t_rttbest) / 2)
bwnd = (int64_t)bw * USERTT / (hz << TCP_RTT_SHIFT) + V_tcp_inflight_stab * tp->t_maxseg / 10;
#undef USERTT
if (tcp_inflight_debug > 0) {
static int ltime;
if ((u_int)(ticks - ltime) >= hz / tcp_inflight_debug) {
ltime = ticks;
printf("%p bw %ld rttbest %d srtt %d bwnd %ld\n",
tp,
bw,
tp->t_rttbest,
tp->t_srtt,
bwnd
);
}
}
if ((long)bwnd < V_tcp_inflight_min)
bwnd = V_tcp_inflight_min;
if (bwnd > V_tcp_inflight_max)
bwnd = V_tcp_inflight_max;
if ((long)bwnd < tp->t_maxseg * 2)
bwnd = tp->t_maxseg * 2;
tp->snd_bwnd = bwnd;
}
#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)
{
INIT_VNET_IPSEC(curvnet);
union sockaddr_union dst;
struct ippseudo ippseudo;
MD5_CTX ctx;
int doff;
struct ip *ip;
struct ipovly *ipovly;
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) {
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;
#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) {
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;
#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);
}
#endif /* TCP_SIGNATURE */
static int
sysctl_drop(SYSCTL_HANDLER_ARGS)
{
INIT_VNET_INET(curvnet);
#ifdef INET6
INIT_VNET_INET6(curvnet);
#endif
/* 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;
struct in6_addr f6, l6;
#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
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;
default:
return (EINVAL);
}
INP_INFO_WLOCK(&V_tcbinfo);
switch (addrs[0].ss_family) {
#ifdef INET6
case AF_INET6:
inp = in6_pcblookup_hash(&V_tcbinfo, &f6, fin6->sin6_port,
&l6, lin6->sin6_port, 0, NULL);
break;
#endif
case AF_INET:
inp = in_pcblookup_hash(&V_tcbinfo, fin->sin_addr,
fin->sin_port, lin->sin_addr, lin->sin_port, 0, NULL);
break;
}
if (inp != NULL) {
INP_WLOCK(inp);
if (inp->inp_vflag & 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_vflag & 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_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_addrs(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 */
/* Is logging enabled? */
if (tcp_log_debug == 0 && tcp_log_in_vain == 0)
return (NULL);
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 */
} 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));
} 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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