/* * Copyright (c) 2000-2008 Apple Inc. All rights reserved. * * @APPLE_OSREFERENCE_LICENSE_HEADER_START@ * * This file contains Original Code and/or Modifications of Original Code * as defined in and that are subject to the Apple Public Source License * Version 2.0 (the 'License'). You may not use this file except in * compliance with the License. The rights granted to you under the License * may not be used to create, or enable the creation or redistribution of, * unlawful or unlicensed copies of an Apple operating system, or to * circumvent, violate, or enable the circumvention or violation of, any * terms of an Apple operating system software license agreement. * * Please obtain a copy of the License at * http://www.opensource.apple.com/apsl/ and read it before using this file. * * The Original Code and all software distributed under the License are * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. * Please see the License for the specific language governing rights and * limitations under the License. * * @APPLE_OSREFERENCE_LICENSE_HEADER_END@ */ /* * Copyright (c) 1982, 1986, 1988, 1990, 1993, 1995 * The Regents of the University of California. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This product includes software developed by the University of * California, Berkeley and its contributors. * 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 * $FreeBSD: src/sys/netinet/tcp_subr.c,v 1.73.2.22 2001/08/22 00:59:12 silby Exp $ */ /* * NOTICE: This file was modified by SPARTA, Inc. in 2005 to introduce * support for mandatory and extensible security protections. This notice * is included in support of clause 2.2 (b) of the Apple Public License, * Version 2.0. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #define tcp_minmssoverload fring #define _IP_VHL #include #include #include #include #if INET6 #include #endif #include #if INET6 #include #endif #include #include #include #if INET6 #include #endif #include #include #include #include #include #if INET6 #include #endif #include #if TCPDEBUG #include #endif #include #if IPSEC #include #if INET6 #include #endif #endif /*IPSEC*/ #undef tcp_minmssoverload #if CONFIG_MACF_NET #include #endif /* MAC_NET */ #include #include #define DBG_FNC_TCP_CLOSE NETDBG_CODE(DBG_NETTCP, ((5 << 8) | 2)) extern int tcp_lq_overflow; /* temporary: for testing */ #if IPSEC extern int ipsec_bypass; #endif int tcp_mssdflt = TCP_MSS; SYSCTL_INT(_net_inet_tcp, TCPCTL_MSSDFLT, mssdflt, CTLFLAG_RW, &tcp_mssdflt , 0, "Default TCP Maximum Segment Size"); #if INET6 int tcp_v6mssdflt = TCP6_MSS; SYSCTL_INT(_net_inet_tcp, TCPCTL_V6MSSDFLT, v6mssdflt, CTLFLAG_RW, &tcp_v6mssdflt , 0, "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. */ int tcp_minmss = TCP_MINMSS; SYSCTL_INT(_net_inet_tcp, OID_AUTO, minmss, CTLFLAG_RW, &tcp_minmss , 0, "Minmum TCP Maximum Segment Size"); /* * Number of TCP segments per second we accept from remote host * before we start to calculate average segment size. If average * segment size drops below the minimum TCP MSS we assume a DoS * attack and reset+drop the connection. Care has to be taken not to * set this value too small to not kill interactive type connections * (telnet, SSH) which send many small packets. */ #ifdef FIX_WORKAROUND_FOR_3894301 __private_extern__ int tcp_minmssoverload = TCP_MINMSSOVERLOAD; #else __private_extern__ int tcp_minmssoverload = 0; #endif SYSCTL_INT(_net_inet_tcp, OID_AUTO, minmssoverload, CTLFLAG_RW, &tcp_minmssoverload , 0, "Number of TCP Segments per Second allowed to" "be under the MINMSS Size"); static int tcp_do_rfc1323 = 1; SYSCTL_INT(_net_inet_tcp, TCPCTL_DO_RFC1323, rfc1323, CTLFLAG_RW, &tcp_do_rfc1323 , 0, "Enable rfc1323 (high performance TCP) extensions"); static int tcp_do_rfc1644 = 0; SYSCTL_INT(_net_inet_tcp, TCPCTL_DO_RFC1644, rfc1644, CTLFLAG_RW, &tcp_do_rfc1644 , 0, "Enable rfc1644 (TTCP) extensions"); static int do_tcpdrain = 0; 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_INT(_net_inet_tcp, OID_AUTO, pcbcount, CTLFLAG_RD, &tcbinfo.ipi_count, 0, "Number of active PCBs"); static int icmp_may_rst = 1; SYSCTL_INT(_net_inet_tcp, OID_AUTO, icmp_may_rst, CTLFLAG_RW, &icmp_may_rst, 0, "Certain ICMP unreachable messages may abort connections in SYN_SENT"); static int tcp_strict_rfc1948 = 0; SYSCTL_INT(_net_inet_tcp, OID_AUTO, strict_rfc1948, CTLFLAG_RW, &tcp_strict_rfc1948, 0, "Determines if RFC1948 is followed exactly"); static int tcp_isn_reseed_interval = 0; SYSCTL_INT(_net_inet_tcp, OID_AUTO, isn_reseed_interval, CTLFLAG_RW, &tcp_isn_reseed_interval, 0, "Seconds between reseeding of ISN secret"); static int tcp_background_io_enabled = 1; SYSCTL_INT(_net_inet_tcp, OID_AUTO, background_io_enabled, CTLFLAG_RW, &tcp_background_io_enabled, 0, "Background IO Enabled"); int tcp_TCPTV_MIN = 1; SYSCTL_INT(_net_inet_tcp, OID_AUTO, rtt_min, CTLFLAG_RW, &tcp_TCPTV_MIN, 0, "min rtt value allowed"); __private_extern__ int tcp_use_randomport = 0; SYSCTL_INT(_net_inet_tcp, OID_AUTO, randomize_ports, CTLFLAG_RW, &tcp_use_randomport, 0, "Randomize TCP port numbers"); static void tcp_cleartaocache(void); static void tcp_notify(struct inpcb *, int); struct zone *sack_hole_zone; extern unsigned int total_mb_cnt; extern unsigned int total_cl_cnt; extern int sbspace_factor; extern int tcp_sockthreshold; extern int slowlink_wsize; /* window correction for slow links */ extern int path_mtu_discovery; /* * 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 CONFIG_TCBHASHSIZE #endif __private_extern__ int tcp_tcbhashsize = TCBHASHSIZE; SYSCTL_INT(_net_inet_tcp, OID_AUTO, tcbhashsize, CTLFLAG_RD, &tcp_tcbhashsize, 0, "Size of TCP control-block hashtable"); /* * This is the actual shape of what we allocate using the zone * allocator. Doing it this way allows us to protect both structures * using the same generation count, and also eliminates the overhead * of allocating tcpcbs separately. By hiding the structure here, * we avoid changing most of the rest of the code (although it needs * to be changed, eventually, for greater efficiency). */ #define ALIGNMENT 32 #define ALIGNM1 (ALIGNMENT - 1) struct inp_tp { union { struct inpcb inp; char align[(sizeof(struct inpcb) + ALIGNM1) & ~ALIGNM1]; } inp_tp_u; struct tcpcb tcb; }; #undef ALIGNMENT #undef ALIGNM1 extern struct inpcbhead time_wait_slots[]; extern u_int32_t *delack_bitmask; int get_inpcb_str_size(void); int get_tcp_str_size(void); static void tcpcb_to_otcpcb(struct tcpcb *, struct otcpcb *); int get_inpcb_str_size(void) { return sizeof(struct inpcb); } int get_tcp_str_size(void) { return sizeof(struct tcpcb); } int tcp_freeq(struct tcpcb *tp); /* * Tcp initialization */ void tcp_init() { vm_size_t str_size; int i; struct inpcbinfo *pcbinfo; tcp_ccgen = 1; tcp_cleartaocache(); tcp_keepinit = TCPTV_KEEP_INIT; tcp_keepidle = TCPTV_KEEP_IDLE; tcp_keepintvl = TCPTV_KEEPINTVL; tcp_maxpersistidle = TCPTV_KEEP_IDLE; tcp_msl = TCPTV_MSL; read_random(&tcp_now, sizeof(tcp_now)); tcp_now = tcp_now & 0x3fffffff; /* Starts tcp internal 100ms clock at a random value */ LIST_INIT(&tcb); tcbinfo.listhead = &tcb; pcbinfo = &tcbinfo; if (!powerof2(tcp_tcbhashsize)) { printf("WARNING: TCB hash size not a power of 2\n"); tcp_tcbhashsize = 512; /* safe default */ } tcbinfo.hashsize = tcp_tcbhashsize; tcbinfo.hashbase = hashinit(tcp_tcbhashsize, M_PCB, &tcbinfo.hashmask); tcbinfo.porthashbase = hashinit(tcp_tcbhashsize, M_PCB, &tcbinfo.porthashmask); str_size = (vm_size_t) sizeof(struct inp_tp); tcbinfo.ipi_zone = (void *) zinit(str_size, 120000*str_size, 8192, "tcpcb"); sack_hole_zone = zinit(str_size, 120000*str_size, 8192, "sack_hole zone"); tcp_reass_maxseg = nmbclusters / 16; #if 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 /* * allocate lock group attribute and group for tcp pcb mutexes */ pcbinfo->mtx_grp_attr = lck_grp_attr_alloc_init(); pcbinfo->mtx_grp = lck_grp_alloc_init("tcppcb", pcbinfo->mtx_grp_attr); /* * allocate the lock attribute for tcp pcb mutexes */ pcbinfo->mtx_attr = lck_attr_alloc_init(); if ((pcbinfo->mtx = lck_rw_alloc_init(pcbinfo->mtx_grp, pcbinfo->mtx_attr)) == NULL) { printf("tcp_init: mutex not alloced!\n"); return; /* pretty much dead if this fails... */ } delack_bitmask = _MALLOC((4 * tcp_tcbhashsize)/32, M_PCB, M_WAITOK); if (delack_bitmask == 0) panic("Delack Memory"); for (i=0; i < (tcbinfo.hashsize / 32); i++) delack_bitmask[i] = 0; for (i=0; i < N_TIME_WAIT_SLOTS; i++) { LIST_INIT(&time_wait_slots[i]); } timeout(tcp_fasttimo, NULL, hz/TCP_RETRANSHZ); } /* * 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 tcp_fillheaders(tp, ip_ptr, tcp_ptr) struct tcpcb *tp; void *ip_ptr; void *tcp_ptr; { struct inpcb *inp = tp->t_inpcb; struct tcphdr *tcp_hdr = (struct tcphdr *)tcp_ptr; #if 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->in6p_flowinfo & 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 = sizeof(struct tcphdr); ip6->ip6_src = inp->in6p_laddr; ip6->ip6_dst = inp->in6p_faddr; tcp_hdr->th_sum = 0; } else #endif { struct ip *ip = (struct ip *) ip_ptr; ip->ip_vhl = IP_VHL_BORING; ip->ip_tos = 0; ip->ip_len = 0; ip->ip_id = 0; ip->ip_off = 0; ip->ip_ttl = 0; ip->ip_sum = 0; ip->ip_p = IPPROTO_TCP; ip->ip_src = inp->inp_laddr; ip->ip_dst = inp->inp_faddr; tcp_hdr->th_sum = in_pseudo(ip->ip_src.s_addr, ip->ip_dst.s_addr, htons(sizeof(struct tcphdr) + IPPROTO_TCP)); } tcp_hdr->th_sport = inp->inp_lport; tcp_hdr->th_dport = inp->inp_fport; tcp_hdr->th_seq = 0; tcp_hdr->th_ack = 0; tcp_hdr->th_x2 = 0; tcp_hdr->th_off = 5; tcp_hdr->th_flags = 0; tcp_hdr->th_win = 0; tcp_hdr->th_urp = 0; } /* * 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 * tcp_maketemplate(tp) struct tcpcb *tp; { struct mbuf *m; struct tcptemp *n; m = m_get(M_DONTWAIT, MT_HEADER); if (m == NULL) return (0); m->m_len = sizeof(struct tcptemp); n = mtod(m, struct tcptemp *); tcp_fillheaders(tp, (void *)&n->tt_ipgen, (void *)&n->tt_t); return (n); } /* * Send a single message to the TCP at address specified by * the given TCP/IP header. If m == 0, 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, register struct tcphdr *th, register struct mbuf *m, tcp_seq ack, tcp_seq seq, int flags, unsigned int ifscope ) { register int tlen; int win = 0; struct route *ro = 0; struct route sro; struct ip *ip; struct tcphdr *nth; #if INET6 struct route_in6 *ro6 = 0; struct route_in6 sro6; struct ip6_hdr *ip6; int isipv6; #endif /* INET6 */ #if INET6 isipv6 = IP_VHL_V(((struct ip *)ipgen)->ip_vhl) == 6; ip6 = ipgen; #endif /* INET6 */ ip = ipgen; if (tp) { if (!(flags & TH_RST)) { win = tcp_sbspace(tp); if (win > (int32_t)TCP_MAXWIN << tp->rcv_scale) win = (int32_t)TCP_MAXWIN << tp->rcv_scale; } #if INET6 if (isipv6) ro6 = &tp->t_inpcb->in6p_route; else #endif /* INET6 */ ro = &tp->t_inpcb->inp_route; } else { #if INET6 if (isipv6) { ro6 = &sro6; bzero(ro6, sizeof *ro6); } else #endif /* INET6 */ { ro = &sro; bzero(ro, sizeof *ro); } } if (m == 0) { m = m_gethdr(M_DONTWAIT, MT_HEADER); /* MAC-OK */ if (m == NULL) return; tlen = 0; m->m_data += max_linkhdr; #if 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 { m_freem(m->m_next); m->m_next = 0; 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; } #if 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 } #if INET6 if (isipv6) { 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 = ip_defttl; } m->m_len = tlen; m->m_pkthdr.len = tlen; m->m_pkthdr.rcvif = 0; #if CONFIG_MACF_NET if (tp != NULL && tp->t_inpcb != NULL) { /* * Packet is associated with a socket, so allow the * label of the response to reflect the socket label. */ mac_mbuf_label_associate_inpcb(tp->t_inpcb, 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) nth->th_win = htons((u_short) (win >> tp->rcv_scale)); else nth->th_win = htons((u_short)win); nth->th_urp = 0; #if 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 ? tp->t_inpcb : NULL, ro6 && ro6->ro_rt ? ro6->ro_rt->rt_ifp : 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); } #if TCPDEBUG if (tp == NULL || (tp->t_inpcb->inp_socket->so_options & SO_DEBUG)) tcp_trace(TA_OUTPUT, 0, tp, mtod(m, void *), th, 0); #endif #if IPSEC if (ipsec_bypass == 0 && ipsec_setsocket(m, tp ? tp->t_inpcb->inp_socket : NULL) != 0) { m_freem(m); return; } #endif #if INET6 if (isipv6) { (void)ip6_output(m, NULL, ro6, 0, NULL, NULL, 0); if (ro6 == &sro6 && ro6->ro_rt) { rtfree(ro6->ro_rt); ro6->ro_rt = NULL; } } else #endif /* INET6 */ { struct ip_out_args ipoa = { ifscope }; if (ro != &sro) { /* Copy the cached route and take an extra reference */ inp_route_copyout(tp->t_inpcb, &sro); } /* * For consistency, pass a local route copy. */ (void) ip_output(m, NULL, &sro, IP_OUTARGS, NULL, &ipoa); if (ro != &sro) { /* Synchronize cached PCB route */ inp_route_copyin(tp->t_inpcb, &sro); } else if (sro.ro_rt != NULL) { rtfree(sro.ro_rt); } } } /* * 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(inp) struct inpcb *inp; { struct inp_tp *it; register struct tcpcb *tp; register struct socket *so = inp->inp_socket; #if INET6 int isipv6 = (inp->inp_vflag & INP_IPV6) != 0; #endif /* INET6 */ if (so->cached_in_sock_layer == 0) { it = (struct inp_tp *)inp; tp = &it->tcb; } else tp = (struct tcpcb *) inp->inp_saved_ppcb; bzero((char *) tp, sizeof(struct tcpcb)); LIST_INIT(&tp->t_segq); tp->t_maxseg = tp->t_maxopd = #if INET6 isipv6 ? tcp_v6mssdflt : #endif /* INET6 */ tcp_mssdflt; if (tcp_do_rfc1323) tp->t_flags = (TF_REQ_SCALE|TF_REQ_TSTMP); tp->sack_enable = tcp_do_sack; 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_TCPTV_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->snd_ssthresh_prev = TCP_MAXWIN << TCP_MAX_WINSHIFT; tp->t_rcvtime = 0; tp->t_bw_rtttime = 0; /* * 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 = ip_defttl; inp->inp_ppcb = (caddr_t)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(tp, errno) register struct tcpcb *tp; int errno; { struct socket *so = tp->t_inpcb->inp_socket; if (TCPS_HAVERCVDSYN(tp->t_state)) { tp->t_state = TCPS_CLOSED; (void) tcp_output(tp); tcpstat.tcps_drops++; } else tcpstat.tcps_conndrops++; if (errno == ETIMEDOUT && tp->t_softerror) errno = tp->t_softerror; so->so_error = errno; return (tcp_close(tp)); } /* * Close a TCP control block: * discard all space held by the tcp * discard internet protocol block * wake up any sleepers */ struct tcpcb * tcp_close(tp) register struct tcpcb *tp; { struct inpcb *inp = tp->t_inpcb; struct socket *so = inp->inp_socket; #if INET6 int isipv6 = (inp->inp_vflag & INP_IPV6) != 0; #endif /* INET6 */ struct rtentry *rt; int dosavessthresh; if ( inp->inp_ppcb == NULL) /* tcp_close was called previously, bail */ return NULL; /* Clear the timers before we delete the PCB. */ { int i; for (i = 0; i < TCPT_NTIMERS; i++) { tp->t_timer[i] = 0; } } KERNEL_DEBUG(DBG_FNC_TCP_CLOSE | DBG_FUNC_START, tp,0,0,0,0); switch (tp->t_state) { case TCPS_ESTABLISHED: case TCPS_FIN_WAIT_1: case TCPS_CLOSING: case TCPS_CLOSE_WAIT: case TCPS_LAST_ACK: break; } /* * If another thread for this tcp is currently in ip (indicated by * the TF_SENDINPROG flag), defer the cleanup until after it returns * back to tcp. This is done to serialize the close until after all * pending output is finished, in order to avoid having the PCB be * detached and the cached route cleaned, only for ip to cache the * route back into the PCB again. Note that we've cleared all the * timers at this point. Set TF_CLOSING to indicate to tcp_output() * that is should call us again once it returns from ip; at that * point both flags should be cleared and we can proceed further * with the cleanup. */ if (tp->t_flags & (TF_CLOSING|TF_SENDINPROG)) { tp->t_flags |= TF_CLOSING; return (NULL); } #if INET6 rt = isipv6 ? inp->in6p_route.ro_rt : inp->inp_route.ro_rt; #else rt = inp->inp_route.ro_rt; #endif if (rt != NULL) RT_LOCK_SPIN(rt); /* * If we got enough samples through the srtt filter, * save the rtt and rttvar in the routing entry. * 'Enough' is arbitrarily defined as the 16 samples. * 16 samples is enough for the srtt filter to converge * to within 5% of the correct value; fewer samples and * we could save a very bogus rtt. * * Don't update the default route's characteristics and don't * update anything that the user "locked". */ if (tp->t_rttupdated >= 16) { register u_int32_t i = 0; #if INET6 if (isipv6) { struct sockaddr_in6 *sin6; if (rt == NULL) goto no_valid_rt; sin6 = (struct sockaddr_in6 *)rt_key(rt); if (IN6_IS_ADDR_UNSPECIFIED(&sin6->sin6_addr)) goto no_valid_rt; } else #endif /* INET6 */ if (rt == NULL || !(rt->rt_flags & RTF_UP) || ((struct sockaddr_in *)rt_key(rt))->sin_addr.s_addr == INADDR_ANY || rt->generation_id != route_generation) { if (tp->t_state >= TCPS_CLOSE_WAIT) tp->t_state = TCPS_CLOSING; goto no_valid_rt; } RT_LOCK_ASSERT_HELD(rt); if ((rt->rt_rmx.rmx_locks & RTV_RTT) == 0) { i = tp->t_srtt * (RTM_RTTUNIT / (TCP_RETRANSHZ * TCP_RTT_SCALE)); if (rt->rt_rmx.rmx_rtt && i) /* * filter this update to half the old & half * the new values, converting scale. * See route.h and tcp_var.h for a * description of the scaling constants. */ rt->rt_rmx.rmx_rtt = (rt->rt_rmx.rmx_rtt + i) / 2; else rt->rt_rmx.rmx_rtt = i; tcpstat.tcps_cachedrtt++; } if ((rt->rt_rmx.rmx_locks & RTV_RTTVAR) == 0) { i = tp->t_rttvar * (RTM_RTTUNIT / (TCP_RETRANSHZ * TCP_RTTVAR_SCALE)); if (rt->rt_rmx.rmx_rttvar && i) rt->rt_rmx.rmx_rttvar = (rt->rt_rmx.rmx_rttvar + i) / 2; else rt->rt_rmx.rmx_rttvar = i; tcpstat.tcps_cachedrttvar++; } /* * The old comment here said: * update the pipelimit (ssthresh) if it has been updated * already or if a pipesize was specified & the threshhold * got below half the pipesize. I.e., wait for bad news * before we start updating, then update on both good * and bad news. * * But we want to save the ssthresh even if no pipesize is * specified explicitly in the route, because such * connections still have an implicit pipesize specified * by the global tcp_sendspace. In the absence of a reliable * way to calculate the pipesize, it will have to do. */ i = tp->snd_ssthresh; if (rt->rt_rmx.rmx_sendpipe != 0) dosavessthresh = (i < rt->rt_rmx.rmx_sendpipe / 2); else dosavessthresh = (i < so->so_snd.sb_hiwat / 2); if (((rt->rt_rmx.rmx_locks & RTV_SSTHRESH) == 0 && i != 0 && rt->rt_rmx.rmx_ssthresh != 0) || dosavessthresh) { /* * convert the limit from user data bytes to * packets then to packet data bytes. */ i = (i + tp->t_maxseg / 2) / tp->t_maxseg; if (i < 2) i = 2; i *= (u_int32_t)(tp->t_maxseg + #if INET6 (isipv6 ? sizeof (struct ip6_hdr) + sizeof (struct tcphdr) : #endif sizeof (struct tcpiphdr) #if INET6 ) #endif ); if (rt->rt_rmx.rmx_ssthresh) rt->rt_rmx.rmx_ssthresh = (rt->rt_rmx.rmx_ssthresh + i) / 2; else rt->rt_rmx.rmx_ssthresh = i; tcpstat.tcps_cachedssthresh++; } } /* * Mark route for deletion if no information is cached. */ if (rt != NULL && (so->so_flags & SOF_OVERFLOW) && tcp_lq_overflow) { if (!(rt->rt_rmx.rmx_locks & RTV_RTT) && rt->rt_rmx.rmx_rtt == 0) { rt->rt_flags |= RTF_DELCLONE; } } no_valid_rt: if (rt != NULL) RT_UNLOCK(rt); /* free the reassembly queue, if any */ (void) tcp_freeq(tp); tcp_free_sackholes(tp); /* Free the packet list */ if (tp->t_pktlist_head != NULL) m_freem_list(tp->t_pktlist_head); TCP_PKTLIST_CLEAR(tp); #ifdef __APPLE__ if (so->cached_in_sock_layer) inp->inp_saved_ppcb = (caddr_t) tp; #endif soisdisconnected(so); #if INET6 if (INP_CHECK_SOCKAF(so, AF_INET6)) in6_pcbdetach(inp); else #endif /* INET6 */ in_pcbdetach(inp); tcpstat.tcps_closed++; KERNEL_DEBUG(DBG_FNC_TCP_CLOSE | DBG_FUNC_END, tcpstat.tcps_closed,0,0,0,0); return ((struct tcpcb *)0); } int tcp_freeq(tp) struct tcpcb *tp; { register struct tseg_qent *q; int rv = 0; while((q = LIST_FIRST(&tp->t_segq)) != NULL) { LIST_REMOVE(q, tqe_q); m_freem(q->tqe_m); FREE(q, M_TSEGQ); tcp_reass_qsize--; rv = 1; } return (rv); } void tcp_drain() { if (do_tcpdrain) { 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. */ if (!lck_rw_try_lock_exclusive(tcbinfo.mtx)) /* do it next time if the lock is in use */ return; for (inpb = LIST_FIRST(tcbinfo.listhead); inpb; inpb = LIST_NEXT(inpb, inp_list)) { if ((tcpb = intotcpcb(inpb))) { while ((te = LIST_FIRST(&tcpb->t_segq)) != NULL) { LIST_REMOVE(te, tqe_q); m_freem(te->tqe_m); FREE(te, M_TSEGQ); tcp_reass_qsize--; } } } lck_rw_done(tcbinfo.mtx); } } /* * 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 void tcp_notify(inp, error) struct inpcb *inp; int error; { struct tcpcb *tp; if (inp == NULL || (inp->inp_state == INPCB_STATE_DEAD)) return; /* pcb is gone already */ tp = (struct tcpcb *)inp->inp_ppcb; /* * 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; } else if (tp->t_state < TCPS_ESTABLISHED && tp->t_rxtshift > 3 && tp->t_softerror) tcp_drop(tp, error); else tp->t_softerror = error; #if 0 wakeup((caddr_t) &so->so_timeo); sorwakeup(so); sowwakeup(so); #endif } /* * tcpcb_to_otcpcb copies specific bits of a tcpcb to a otcpcb format. * The otcpcb data structure is passed to user space and must not change. */ static void tcpcb_to_otcpcb(struct tcpcb *tp, struct otcpcb *otp) { int i; otp->t_segq = (u_int32_t)(uintptr_t)tp->t_segq.lh_first; otp->t_dupacks = tp->t_dupacks; for (i = 0; i < TCPT_NTIMERS; i++) otp->t_timer[i] = tp->t_timer[i]; otp->t_inpcb = (_TCPCB_PTR(struct inpcb *))(uintptr_t)tp->t_inpcb; otp->t_state = tp->t_state; otp->t_flags = tp->t_flags; otp->t_force = tp->t_force; otp->snd_una = tp->snd_una; otp->snd_max = tp->snd_max; otp->snd_nxt = tp->snd_nxt; otp->snd_up = tp->snd_up; otp->snd_wl1 = tp->snd_wl1; otp->snd_wl2 = tp->snd_wl2; otp->iss = tp->iss; otp->irs = tp->irs; otp->rcv_nxt = tp->rcv_nxt; otp->rcv_adv = tp->rcv_adv; otp->rcv_wnd = tp->rcv_wnd; otp->rcv_up = tp->rcv_up; otp->snd_wnd = tp->snd_wnd; otp->snd_cwnd = tp->snd_cwnd; otp->snd_ssthresh = tp->snd_ssthresh; otp->t_maxopd = tp->t_maxopd; otp->t_rcvtime = tp->t_rcvtime; otp->t_starttime = tp->t_starttime; otp->t_rtttime = tp->t_rtttime; otp->t_rtseq = tp->t_rtseq; otp->t_rxtcur = tp->t_rxtcur; otp->t_maxseg = tp->t_maxseg; otp->t_srtt = tp->t_srtt; otp->t_rttvar = tp->t_rttvar; otp->t_rxtshift = tp->t_rxtshift; otp->t_rttmin = tp->t_rttmin; otp->t_rttupdated = tp->t_rttupdated; otp->max_sndwnd = tp->max_sndwnd; otp->t_softerror = tp->t_softerror; otp->t_oobflags = tp->t_oobflags; otp->t_iobc = tp->t_iobc; otp->snd_scale = tp->snd_scale; otp->rcv_scale = tp->rcv_scale; otp->request_r_scale = tp->request_r_scale; otp->requested_s_scale = tp->requested_s_scale; otp->ts_recent = tp->ts_recent; otp->ts_recent_age = tp->ts_recent_age; otp->last_ack_sent = tp->last_ack_sent; otp->cc_send = tp->cc_send; otp->cc_recv = tp->cc_recv; otp->snd_recover = tp->snd_recover; otp->snd_cwnd_prev = tp->snd_cwnd_prev; otp->snd_ssthresh_prev = tp->snd_ssthresh_prev; otp->t_badrxtwin = tp->t_badrxtwin; } static int tcp_pcblist SYSCTL_HANDLER_ARGS { #pragma unused(oidp, arg1, arg2) int error, i, n; struct inpcb *inp, **inp_list; inp_gen_t gencnt; struct xinpgen xig; int slot; /* * The process of preparing the TCB list is too time-consuming and * resource-intensive to repeat twice on every request. */ lck_rw_lock_shared(tcbinfo.mtx); if (req->oldptr == USER_ADDR_NULL) { n = tcbinfo.ipi_count; req->oldidx = 2 * (sizeof xig) + (n + n/8) * sizeof(struct xtcpcb); lck_rw_done(tcbinfo.mtx); return 0; } if (req->newptr != USER_ADDR_NULL) { lck_rw_done(tcbinfo.mtx); return EPERM; } /* * OK, now we're committed to doing something. */ gencnt = tcbinfo.ipi_gencnt; n = tcbinfo.ipi_count; bzero(&xig, sizeof(xig)); xig.xig_len = sizeof xig; xig.xig_count = n; xig.xig_gen = gencnt; xig.xig_sogen = so_gencnt; error = SYSCTL_OUT(req, &xig, sizeof xig); if (error) { lck_rw_done(tcbinfo.mtx); return error; } /* * We are done if there is no pcb */ if (n == 0) { lck_rw_done(tcbinfo.mtx); return 0; } inp_list = _MALLOC(n * sizeof *inp_list, M_TEMP, M_WAITOK); if (inp_list == 0) { lck_rw_done(tcbinfo.mtx); return ENOMEM; } for (inp = LIST_FIRST(tcbinfo.listhead), i = 0; inp && i < n; inp = LIST_NEXT(inp, inp_list)) { #ifdef __APPLE__ if (inp->inp_gencnt <= gencnt && inp->inp_state != INPCB_STATE_DEAD) #else if (inp->inp_gencnt <= gencnt && !prison_xinpcb(req->p, inp)) #endif inp_list[i++] = inp; } for (slot = 0; slot < N_TIME_WAIT_SLOTS; slot++) { struct inpcb *inpnxt; for (inp = time_wait_slots[slot].lh_first; inp && i < n; inp = inpnxt) { inpnxt = inp->inp_list.le_next; if (inp->inp_gencnt <= gencnt && inp->inp_state != INPCB_STATE_DEAD) inp_list[i++] = inp; } } n = i; error = 0; for (i = 0; i < n; i++) { inp = inp_list[i]; if (inp->inp_gencnt <= gencnt && inp->inp_state != INPCB_STATE_DEAD) { struct xtcpcb xt; caddr_t inp_ppcb; bzero(&xt, sizeof(xt)); xt.xt_len = sizeof xt; /* XXX should avoid extra copy */ inpcb_to_compat(inp, &xt.xt_inp); inp_ppcb = inp->inp_ppcb; if (inp_ppcb != NULL) { tcpcb_to_otcpcb((struct tcpcb *)inp_ppcb, &xt.xt_tp); } else { bzero((char *) &xt.xt_tp, sizeof xt.xt_tp); } if (inp->inp_socket) sotoxsocket(inp->inp_socket, &xt.xt_socket); error = SYSCTL_OUT(req, &xt, sizeof xt); } } 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. */ bzero(&xig, sizeof(xig)); xig.xig_len = sizeof xig; xig.xig_gen = tcbinfo.ipi_gencnt; xig.xig_sogen = so_gencnt; xig.xig_count = tcbinfo.ipi_count; error = SYSCTL_OUT(req, &xig, sizeof xig); } FREE(inp_list, M_TEMP); lck_rw_done(tcbinfo.mtx); return error; } SYSCTL_PROC(_net_inet_tcp, TCPCTL_PCBLIST, pcblist, CTLFLAG_RD, 0, 0, tcp_pcblist, "S,xtcpcb", "List of active TCP connections"); #if !CONFIG_EMBEDDED static void tcpcb_to_xtcpcb64(struct tcpcb *tp, struct xtcpcb64 *otp) { int i; otp->t_segq = (u_int32_t)(uintptr_t)tp->t_segq.lh_first; otp->t_dupacks = tp->t_dupacks; for (i = 0; i < TCPT_NTIMERS; i++) otp->t_timer[i] = tp->t_timer[i]; otp->t_state = tp->t_state; otp->t_flags = tp->t_flags; otp->t_force = tp->t_force; otp->snd_una = tp->snd_una; otp->snd_max = tp->snd_max; otp->snd_nxt = tp->snd_nxt; otp->snd_up = tp->snd_up; otp->snd_wl1 = tp->snd_wl1; otp->snd_wl2 = tp->snd_wl2; otp->iss = tp->iss; otp->irs = tp->irs; otp->rcv_nxt = tp->rcv_nxt; otp->rcv_adv = tp->rcv_adv; otp->rcv_wnd = tp->rcv_wnd; otp->rcv_up = tp->rcv_up; otp->snd_wnd = tp->snd_wnd; otp->snd_cwnd = tp->snd_cwnd; otp->snd_ssthresh = tp->snd_ssthresh; otp->t_maxopd = tp->t_maxopd; otp->t_rcvtime = tp->t_rcvtime; otp->t_starttime = tp->t_starttime; otp->t_rtttime = tp->t_rtttime; otp->t_rtseq = tp->t_rtseq; otp->t_rxtcur = tp->t_rxtcur; otp->t_maxseg = tp->t_maxseg; otp->t_srtt = tp->t_srtt; otp->t_rttvar = tp->t_rttvar; otp->t_rxtshift = tp->t_rxtshift; otp->t_rttmin = tp->t_rttmin; otp->t_rttupdated = tp->t_rttupdated; otp->max_sndwnd = tp->max_sndwnd; otp->t_softerror = tp->t_softerror; otp->t_oobflags = tp->t_oobflags; otp->t_iobc = tp->t_iobc; otp->snd_scale = tp->snd_scale; otp->rcv_scale = tp->rcv_scale; otp->request_r_scale = tp->request_r_scale; otp->requested_s_scale = tp->requested_s_scale; otp->ts_recent = tp->ts_recent; otp->ts_recent_age = tp->ts_recent_age; otp->last_ack_sent = tp->last_ack_sent; otp->cc_send = tp->cc_send; otp->cc_recv = tp->cc_recv; otp->snd_recover = tp->snd_recover; otp->snd_cwnd_prev = tp->snd_cwnd_prev; otp->snd_ssthresh_prev = tp->snd_ssthresh_prev; otp->t_badrxtwin = tp->t_badrxtwin; } static int tcp_pcblist64 SYSCTL_HANDLER_ARGS { #pragma unused(oidp, arg1, arg2) int error, i, n; struct inpcb *inp, **inp_list; inp_gen_t gencnt; struct xinpgen xig; int slot; /* * The process of preparing the TCB list is too time-consuming and * resource-intensive to repeat twice on every request. */ lck_rw_lock_shared(tcbinfo.mtx); if (req->oldptr == USER_ADDR_NULL) { n = tcbinfo.ipi_count; req->oldidx = 2 * (sizeof xig) + (n + n/8) * sizeof(struct xtcpcb64); lck_rw_done(tcbinfo.mtx); return 0; } if (req->newptr != USER_ADDR_NULL) { lck_rw_done(tcbinfo.mtx); return EPERM; } /* * OK, now we're committed to doing something. */ gencnt = tcbinfo.ipi_gencnt; n = tcbinfo.ipi_count; bzero(&xig, sizeof(xig)); xig.xig_len = sizeof xig; xig.xig_count = n; xig.xig_gen = gencnt; xig.xig_sogen = so_gencnt; error = SYSCTL_OUT(req, &xig, sizeof xig); if (error) { lck_rw_done(tcbinfo.mtx); return error; } /* * We are done if there is no pcb */ if (n == 0) { lck_rw_done(tcbinfo.mtx); return 0; } inp_list = _MALLOC(n * sizeof *inp_list, M_TEMP, M_WAITOK); if (inp_list == 0) { lck_rw_done(tcbinfo.mtx); return ENOMEM; } for (inp = LIST_FIRST(tcbinfo.listhead), i = 0; inp && i < n; inp = LIST_NEXT(inp, inp_list)) { #ifdef __APPLE__ if (inp->inp_gencnt <= gencnt && inp->inp_state != INPCB_STATE_DEAD) #else if (inp->inp_gencnt <= gencnt && !prison_xinpcb(req->p, inp)) #endif inp_list[i++] = inp; } for (slot = 0; slot < N_TIME_WAIT_SLOTS; slot++) { struct inpcb *inpnxt; for (inp = time_wait_slots[slot].lh_first; inp && i < n; inp = inpnxt) { inpnxt = inp->inp_list.le_next; if (inp->inp_gencnt <= gencnt && inp->inp_state != INPCB_STATE_DEAD) inp_list[i++] = inp; } } n = i; error = 0; for (i = 0; i < n; i++) { inp = inp_list[i]; if (inp->inp_gencnt <= gencnt && inp->inp_state != INPCB_STATE_DEAD) { struct xtcpcb64 xt; bzero(&xt, sizeof(xt)); xt.xt_len = sizeof xt; inpcb_to_xinpcb64(inp, &xt.xt_inpcb); xt.xt_inpcb.inp_ppcb = (u_int64_t)(uintptr_t)inp->inp_ppcb; if (inp->inp_ppcb != NULL) tcpcb_to_xtcpcb64((struct tcpcb *)inp->inp_ppcb, &xt); if (inp->inp_socket) sotoxsocket64(inp->inp_socket, &xt.xt_inpcb.xi_socket); error = SYSCTL_OUT(req, &xt, sizeof xt); } } 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. */ bzero(&xig, sizeof(xig)); xig.xig_len = sizeof xig; xig.xig_gen = tcbinfo.ipi_gencnt; xig.xig_sogen = so_gencnt; xig.xig_count = tcbinfo.ipi_count; error = SYSCTL_OUT(req, &xig, sizeof xig); } FREE(inp_list, M_TEMP); lck_rw_done(tcbinfo.mtx); return error; } SYSCTL_PROC(_net_inet_tcp, OID_AUTO, pcblist64, CTLFLAG_RD, 0, 0, tcp_pcblist64, "S,xtcpcb64", "List of active TCP connections"); #endif /* !CONFIG_EMBEDDED */ void tcp_ctlinput(cmd, sa, vip) int cmd; struct sockaddr *sa; void *vip; { tcp_seq icmp_tcp_seq; struct ip *ip = vip; struct tcphdr *th; struct in_addr faddr; struct inpcb *inp; struct tcpcb *tp; void (*notify)(struct inpcb *, int) = tcp_notify; struct icmp *icp; 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 (icmp_may_rst && (cmd == PRC_UNREACH_ADMIN_PROHIB || cmd == PRC_UNREACH_PORT) && ip) notify = tcp_drop_syn_sent; else if (PRC_IS_REDIRECT(cmd)) { ip = 0; notify = in_rtchange; } else if (cmd == PRC_HOSTDEAD) ip = 0; /* Source quench is deprecated */ else if (cmd == PRC_QUENCH) return; else if ((unsigned)cmd > PRC_NCMDS || inetctlerrmap[cmd] == 0) return; if (ip) { icp = (struct icmp *)((caddr_t)ip - offsetof(struct icmp, icmp_ip)); th = (struct tcphdr *)((caddr_t)ip + (IP_VHL_HL(ip->ip_vhl) << 2)); inp = in_pcblookup_hash(&tcbinfo, faddr, th->th_dport, ip->ip_src, th->th_sport, 0, NULL); if (inp != NULL && inp->inp_socket != NULL) { tcp_lock(inp->inp_socket, 1, 0); if (in_pcb_checkstate(inp, WNT_RELEASE, 1) == WNT_STOPUSING) { tcp_unlock(inp->inp_socket, 1, 0); return; } 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 and there is a host route to the * original destination, and the MTU is not locked, then * set the MTU in the route to the suggested new value * (if given) and then notify as usual. The ULPs will * notice that the MTU has changed and adapt accordingly. * If no new MTU was suggested, then we guess a new one * less than the current value. If the new MTU is * unreasonably small (defined by sysctl tcp_minmss), then * we reset the MTU to the interface value and enable the * lock bit, indicating that we are no longer doing MTU * discovery. */ struct rtentry *rt; int mtu; struct sockaddr_in icmpsrc = { sizeof (struct sockaddr_in), AF_INET, 0 , { 0 }, { 0,0,0,0,0,0,0,0 } }; icmpsrc.sin_addr = icp->icmp_ip.ip_dst; rt = rtalloc1((struct sockaddr *)&icmpsrc, 0, RTF_CLONING | RTF_PRCLONING); if (rt != NULL) { RT_LOCK(rt); if ((rt->rt_flags & RTF_HOST) && !(rt->rt_rmx.rmx_locks & RTV_MTU)) { mtu = ntohs(icp->icmp_nextmtu); if (!mtu) mtu = ip_next_mtu(rt->rt_rmx. rmx_mtu, 1); #if DEBUG_MTUDISC printf("MTU for %s reduced to %d\n", inet_ntop(AF_INET, &icmpsrc.sin_addr, ipv4str, sizeof (ipv4str)), mtu); #endif if (mtu < max(296, (tcp_minmss + sizeof (struct tcpiphdr)))) { /* rt->rt_rmx.rmx_mtu = rt->rt_ifp->if_mtu; */ rt->rt_rmx.rmx_locks |= RTV_MTU; } else if (rt->rt_rmx.rmx_mtu > mtu) { rt->rt_rmx.rmx_mtu = mtu; } } RT_UNLOCK(rt); rtfree(rt); } } (*notify)(inp, inetctlerrmap[cmd]); } tcp_unlock(inp->inp_socket, 1, 0); } } else in_pcbnotifyall(&tcbinfo, faddr, inetctlerrmap[cmd], notify); } #if INET6 void tcp6_ctlinput(cmd, sa, d) int cmd; struct sockaddr *sa; void *d; { struct tcphdr th; void (*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 deprecated */ 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) { /* * 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(&tcbinfo, sa, th.th_dport, (struct sockaddr *)ip6cp->ip6c_src, th.th_sport, cmd, notify); } else { in6_pcbnotify(&tcbinfo, sa, 0, (struct sockaddr *)(size_t)sa6_src, 0, cmd, 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. * * The ISNs in SYN-ACK packets have no monotonicity requirement, * and should be as unpredictable as possible to avoid the possibility * of spoofing and/or connection hijacking. To satisfy this * requirement, SYN-ACK ISNs are generated via the arc4random() * function. If exact RFC 1948 compliance is requested via sysctl, * these ISNs will be generated just like those in SYN packets. * * 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 to generate sequence numbers. * * For more information on the theory of operation, please see * RFC 1948. * * 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. * * Two sysctls control the generation of ISNs: * * 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. * * net.inet.tcp.strict_rfc1948 controls whether RFC 1948 is followed * strictly. When strict compliance is requested, reseeding is * disabled and SYN-ACKs will be generated in the same manner as * SYNs. Strict mode is disabled by default. * */ #define ISN_BYTES_PER_SECOND 1048576 tcp_seq tcp_new_isn(tp) struct tcpcb *tp; { u_int32_t md5_buffer[4]; tcp_seq new_isn; struct timeval timenow; u_char isn_secret[32]; int isn_last_reseed = 0; MD5_CTX isn_ctx; /* Use arc4random for SYN-ACKs when not in exact RFC1948 mode. */ if (((tp->t_state == TCPS_LISTEN) || (tp->t_state == TCPS_TIME_WAIT)) && tcp_strict_rfc1948 == 0) #ifdef __APPLE__ return random(); #else return arc4random(); #endif getmicrotime(&timenow); /* Seed if this is the first use, reseed if requested. */ if ((isn_last_reseed == 0) || ((tcp_strict_rfc1948 == 0) && (tcp_isn_reseed_interval > 0) && (((u_int)isn_last_reseed + (u_int)tcp_isn_reseed_interval*hz) < (u_int)timenow.tv_sec))) { #ifdef __APPLE__ read_random(&isn_secret, sizeof(isn_secret)); #else read_random_unlimited(&isn_secret, sizeof(isn_secret)); #endif isn_last_reseed = timenow.tv_sec; } /* 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)); #if 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 *) &isn_secret, sizeof(isn_secret)); MD5Final((u_char *) &md5_buffer, &isn_ctx); new_isn = (tcp_seq) md5_buffer[0]; new_isn += timenow.tv_sec * (ISN_BYTES_PER_SECOND / hz); 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. */ void tcp_drop_syn_sent(inp, errno) struct inpcb *inp; int errno; { struct tcpcb *tp = intotcpcb(inp); if (tp && tp->t_state == TCPS_SYN_SENT) tcp_drop(tp, errno); } /* * 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. */ void tcp_mtudisc( struct inpcb *inp, __unused int errno ) { struct tcpcb *tp = intotcpcb(inp); struct rtentry *rt; struct rmxp_tao *taop; struct socket *so = inp->inp_socket; int offered; int mss; #if INET6 int isipv6 = (tp->t_inpcb->inp_vflag & INP_IPV6) != 0; #endif /* INET6 */ if (tp) { #if INET6 if (isipv6) rt = tcp_rtlookup6(inp); else #endif /* INET6 */ rt = tcp_rtlookup(inp, IFSCOPE_NONE); if (!rt || !rt->rt_rmx.rmx_mtu) { tp->t_maxopd = tp->t_maxseg = #if INET6 isipv6 ? tcp_v6mssdflt : #endif /* INET6 */ tcp_mssdflt; /* Route locked during lookup above */ if (rt != NULL) RT_UNLOCK(rt); return; } taop = rmx_taop(rt->rt_rmx); offered = taop->tao_mssopt; mss = rt->rt_rmx.rmx_mtu - #if INET6 (isipv6 ? sizeof(struct ip6_hdr) + sizeof(struct tcphdr) : #endif /* INET6 */ sizeof(struct tcpiphdr) #if INET6 ) #endif /* INET6 */ ; /* Route locked during lookup above */ RT_UNLOCK(rt); if (offered) mss = min(mss, offered); /* * XXX - The above conditional probably violates the TCP * spec. The problem is that, since we don't know the * other end's MSS, we are supposed to use a conservative * default. But, if we do that, then MTU discovery will * never actually take place, because the conservative * default is much less than the MTUs typically seen * on the Internet today. For the moment, we'll sweep * this under the carpet. * * The conservative default might not actually be a problem * if the only case this occurs is when sending an initial * SYN with options and data to a host we've never talked * to before. Then, they will reply with an MSS value which * will get recorded and the new parameters should get * recomputed. For Further Study. */ if (tp->t_maxopd <= mss) return; tp->t_maxopd = mss; if ((tp->t_flags & (TF_REQ_TSTMP|TF_NOOPT)) == TF_REQ_TSTMP && (tp->t_flags & TF_RCVD_TSTMP) == TF_RCVD_TSTMP) mss -= TCPOLEN_TSTAMP_APPA; if (so->so_snd.sb_hiwat < mss) mss = so->so_snd.sb_hiwat; tp->t_maxseg = mss; tcpstat.tcps_mturesent++; tp->t_rtttime = 0; tp->snd_nxt = tp->snd_una; tcp_output(tp); } } /* * Look-up the routing entry to the peer of this inpcb. If no route * is found and it cannot be allocated the return NULL. This routine * is called by TCP routines that access the rmx structure and by tcp_mss * to get the interface MTU. If a route is found, this routine will * hold the rtentry lock; the caller is responsible for unlocking. */ struct rtentry * tcp_rtlookup(inp, input_ifscope) struct inpcb *inp; unsigned int input_ifscope; { struct route *ro; struct rtentry *rt; struct tcpcb *tp; lck_mtx_assert(rnh_lock, LCK_MTX_ASSERT_NOTOWNED); ro = &inp->inp_route; if ((rt = ro->ro_rt) != NULL) RT_LOCK(rt); if (rt == NULL || !(rt->rt_flags & RTF_UP) || rt->generation_id != route_generation) { /* No route yet, so try to acquire one */ if (inp->inp_faddr.s_addr != INADDR_ANY) { unsigned int ifscope; ro->ro_dst.sa_family = AF_INET; ro->ro_dst.sa_len = sizeof(struct sockaddr_in); ((struct sockaddr_in *) &ro->ro_dst)->sin_addr = inp->inp_faddr; /* * If the socket was bound to an interface, then * the bound-to-interface takes precedence over * the inbound interface passed in by the caller * (if we get here as part of the output path then * input_ifscope is IFSCOPE_NONE). */ ifscope = (inp->inp_flags & INP_BOUND_IF) ? inp->inp_boundif : input_ifscope; if (rt != NULL) RT_UNLOCK(rt); rtalloc_scoped_ign(ro, 0, ifscope); if ((rt = ro->ro_rt) != NULL) RT_LOCK(rt); } } /* * Update MTU discovery determination. Don't do it if: * 1) it is disabled via the sysctl * 2) the route isn't up * 3) the MTU is locked (if it is, then discovery has been * disabled) */ tp = intotcpcb(inp); if (!path_mtu_discovery || ((rt != NULL) && (!(rt->rt_flags & RTF_UP) || (rt->rt_rmx.rmx_locks & RTV_MTU)))) tp->t_flags &= ~TF_PMTUD; else tp->t_flags |= TF_PMTUD; #if CONFIG_IFEF_NOWINDOWSCALE if (tcp_obey_ifef_nowindowscale && tp->t_state == TCPS_SYN_SENT && rt != NULL && rt->rt_ifp != NULL && (rt->rt_ifp->if_eflags & IFEF_NOWINDOWSCALE)) { /* Window scaling is enabled on this interface */ tp->t_flags &= ~TF_REQ_SCALE; } #endif if (rt != NULL && rt->rt_ifp != NULL) { somultipages(inp->inp_socket, (rt->rt_ifp->if_hwassist & IFNET_MULTIPAGES)); tcp_set_tso(tp, rt->rt_ifp); } /* * Caller needs to call RT_UNLOCK(rt). */ return rt; } #if INET6 struct rtentry * tcp_rtlookup6(inp) struct inpcb *inp; { struct route_in6 *ro6; struct rtentry *rt; struct tcpcb *tp; lck_mtx_assert(rnh_lock, LCK_MTX_ASSERT_NOTOWNED); ro6 = &inp->in6p_route; if ((rt = ro6->ro_rt) != NULL) RT_LOCK(rt); if (rt == NULL || !(rt->rt_flags & RTF_UP) || rt->generation_id != route_generation) { /* No route yet, so try to acquire one */ if (!IN6_IS_ADDR_UNSPECIFIED(&inp->in6p_faddr)) { struct sockaddr_in6 *dst6; dst6 = (struct sockaddr_in6 *)&ro6->ro_dst; dst6->sin6_family = AF_INET6; dst6->sin6_len = sizeof(*dst6); dst6->sin6_addr = inp->in6p_faddr; if (rt != NULL) RT_UNLOCK(rt); rtalloc_ign((struct route *)ro6, 0); if ((rt = ro6->ro_rt) != NULL) RT_LOCK(rt); } } /* * Update path MTU Discovery determination * while looking up the route: * 1) we have a valid route to the destination * 2) the MTU is not locked (if it is, then discovery has been * disabled) */ tp = intotcpcb(inp); /* * Update MTU discovery determination. Don't do it if: * 1) it is disabled via the sysctl * 2) the route isn't up * 3) the MTU is locked (if it is, then discovery has been * disabled) */ if (!path_mtu_discovery || ((rt != NULL) && (!(rt->rt_flags & RTF_UP) || (rt->rt_rmx.rmx_locks & RTV_MTU)))) tp->t_flags &= ~TF_PMTUD; else tp->t_flags |= TF_PMTUD; #if CONFIG_IFEF_NOWINDOWSCALE if (tcp_obey_ifef_nowindowscale && tp->t_state == TCPS_SYN_SENT && rt != NULL && rt->rt_ifp != NULL && (rt->rt_ifp->if_eflags & IFEF_NOWINDOWSCALE)) { /* Window scaling is not enabled on this interface */ tp->t_flags &= ~TF_REQ_SCALE; } #endif if (rt != NULL && rt->rt_ifp != NULL) { somultipages(inp->inp_socket, (rt->rt_ifp->if_hwassist & IFNET_MULTIPAGES)); tcp_set_tso(tp, rt->rt_ifp); } /* * Caller needs to call RT_UNLOCK(rt). */ return rt; } #endif /* INET6 */ #if IPSEC /* compute ESP/AH header size for TCP, including outer IP header. */ size_t ipsec_hdrsiz_tcp(tp) struct tcpcb *tp; { struct inpcb *inp; struct mbuf *m; size_t hdrsiz; struct ip *ip; #if INET6 struct ip6_hdr *ip6 = NULL; #endif /* INET6 */ struct tcphdr *th; if ((tp == NULL) || ((inp = tp->t_inpcb) == NULL)) return 0; MGETHDR(m, M_DONTWAIT, MT_DATA); /* MAC-OK */ if (!m) return 0; #if 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); tcp_fillheaders(tp, 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); tcp_fillheaders(tp, ip, th); hdrsiz = ipsec4_hdrsiz(m, IPSEC_DIR_OUTBOUND, inp); } m_free(m); return hdrsiz; } #endif /*IPSEC*/ /* * Return a pointer to the cached information about the remote host. * The cached information is stored in the protocol specific part of * the route metrics. */ struct rmxp_tao * tcp_gettaocache(inp) struct inpcb *inp; { struct rtentry *rt; struct rmxp_tao *taop; #if INET6 if ((inp->inp_vflag & INP_IPV6) != 0) rt = tcp_rtlookup6(inp); else #endif /* INET6 */ rt = tcp_rtlookup(inp, IFSCOPE_NONE); /* Make sure this is a host route and is up. */ if (rt == NULL || (rt->rt_flags & (RTF_UP|RTF_HOST)) != (RTF_UP|RTF_HOST)) { /* Route locked during lookup above */ if (rt != NULL) RT_UNLOCK(rt); return NULL; } taop = rmx_taop(rt->rt_rmx); /* Route locked during lookup above */ RT_UNLOCK(rt); return (taop); } /* * Clear all the TAO cache entries, called from tcp_init. * * XXX * This routine is just an empty one, because we assume that the routing * routing tables are initialized at the same time when TCP, so there is * nothing in the cache left over. */ static void tcp_cleartaocache() { } int tcp_lock(struct socket *so, int refcount, void *lr) { void *lr_saved; if (lr == NULL) lr_saved = __builtin_return_address(0); else lr_saved = lr; if (so->so_pcb != NULL) { lck_mtx_lock(((struct inpcb *)so->so_pcb)->inpcb_mtx); } else { panic("tcp_lock: so=%p NO PCB! lr=%p lrh= %s\n", so, lr_saved, solockhistory_nr(so)); /* NOTREACHED */ } if (so->so_usecount < 0) { panic("tcp_lock: so=%p so_pcb=%p lr=%p ref=%x lrh= %s\n", so, so->so_pcb, lr_saved, so->so_usecount, solockhistory_nr(so)); /* NOTREACHED */ } if (refcount) so->so_usecount++; so->lock_lr[so->next_lock_lr] = lr_saved; so->next_lock_lr = (so->next_lock_lr+1) % SO_LCKDBG_MAX; return (0); } int tcp_unlock(struct socket *so, int refcount, void *lr) { void *lr_saved; if (lr == NULL) lr_saved = __builtin_return_address(0); else lr_saved = lr; #ifdef MORE_TCPLOCK_DEBUG printf("tcp_unlock: so=%p sopcb=%p lock=%p ref=%x lr=%p\n", so, so->so_pcb, ((struct inpcb *)so->so_pcb)->inpcb_mtx, so->so_usecount, lr_saved); #endif if (refcount) so->so_usecount--; if (so->so_usecount < 0) { panic("tcp_unlock: so=%p usecount=%x lrh= %s\n", so, so->so_usecount, solockhistory_nr(so)); /* NOTREACHED */ } if (so->so_pcb == NULL) { panic("tcp_unlock: so=%p NO PCB usecount=%x lr=%p lrh= %s\n", so, so->so_usecount, lr_saved, solockhistory_nr(so)); /* NOTREACHED */ } else { lck_mtx_assert(((struct inpcb *)so->so_pcb)->inpcb_mtx, LCK_MTX_ASSERT_OWNED); so->unlock_lr[so->next_unlock_lr] = lr_saved; so->next_unlock_lr = (so->next_unlock_lr+1) % SO_LCKDBG_MAX; lck_mtx_unlock(((struct inpcb *)so->so_pcb)->inpcb_mtx); } return (0); } lck_mtx_t * tcp_getlock( struct socket *so, __unused int locktype) { struct inpcb *inp = sotoinpcb(so); if (so->so_pcb) { if (so->so_usecount < 0) panic("tcp_getlock: so=%p usecount=%x lrh= %s\n", so, so->so_usecount, solockhistory_nr(so)); return(inp->inpcb_mtx); } else { panic("tcp_getlock: so=%p NULL so_pcb %s\n", so, solockhistory_nr(so)); return (so->so_proto->pr_domain->dom_mtx); } } int32_t tcp_sbspace(struct tcpcb *tp) { struct sockbuf *sb = &tp->t_inpcb->inp_socket->so_rcv; int32_t space, newspace; space = ((int32_t) imin((sb->sb_hiwat - sb->sb_cc), (sb->sb_mbmax - sb->sb_mbcnt))); if (space < 0) space = 0; #if TRAFFIC_MGT if (tp->t_inpcb->inp_socket->so_traffic_mgt_flags & TRAFFIC_MGT_SO_BACKGROUND) { if (tcp_background_io_enabled && tp->t_inpcb->inp_socket->so_traffic_mgt_flags & TRAFFIC_MGT_SO_BG_SUPPRESSED) { tp->t_flags |= TF_RXWIN0SENT; return 0; /* Triggers TCP window closing by responding there is no space */ } } #endif /* TRAFFIC_MGT */ /* Avoid inscreasing window size if the current window * is already very low, we could be in "persist" mode and * we could break some apps (see rdar://5409343) */ if (space < tp->t_maxseg) return space; /* Clip window size for slower link */ if (((tp->t_flags & TF_SLOWLINK) != 0) && slowlink_wsize > 0 ) return imin(space, slowlink_wsize); /* * Check for ressources constraints before over-ajusting the amount of space we can * advertise in the TCP window size updates. */ if (sbspace_factor && (tp->t_inpcb->inp_pcbinfo->ipi_count < tcp_sockthreshold) && (total_mb_cnt / 8) < (mbstat.m_clusters / sbspace_factor)) { if (space < (int32_t)(sb->sb_maxused - sb->sb_cc)) {/* make sure we don't constrain the window if we have enough ressources */ space = (int32_t) imax((sb->sb_maxused - sb->sb_cc), tp->rcv_maxbyps); } newspace = (int32_t) imax(((int32_t)sb->sb_maxused - sb->sb_cc), (int32_t)tp->rcv_maxbyps); if (newspace > space) space = newspace; } return space; } /* * Checks TCP Segment Offloading capability for a given connection and interface pair. */ void tcp_set_tso(tp, ifp) struct tcpcb *tp; struct ifnet *ifp; { #if INET6 struct inpcb *inp = tp->t_inpcb; int isipv6 = (inp->inp_vflag & INP_IPV6) != 0; if (isipv6) { /* * Radar 6921834: Disable TSO IPv6 because there is no support * for TSO & HW checksum in ip6_output yet */ #if 0 if (ifp && ifp->if_hwassist & IFNET_TSO_IPV6) { tp->t_flags |= TF_TSO; if (ifp->if_tso_v6_mtu != 0) tp->tso_max_segment_size = ifp->if_tso_v6_mtu; else tp->tso_max_segment_size = TCP_MAXWIN; } else tp->t_flags &= ~TF_TSO; #endif } else #endif /* INET6 */ { if (ifp && ifp->if_hwassist & IFNET_TSO_IPV4) { tp->t_flags |= TF_TSO; if (ifp->if_tso_v4_mtu != 0) tp->tso_max_segment_size = ifp->if_tso_v4_mtu; else tp->tso_max_segment_size = TCP_MAXWIN; } else tp->t_flags &= ~TF_TSO; } } /* DSEP Review Done pl-20051213-v02 @3253,@3391,@3400 */