X-Git-Url: https://git.saurik.com/apple/xnu.git/blobdiff_plain/0b4e3aa066abc0728aacb4bbeb86f53f9737156e..d9a64523371fa019c4575bb400cbbc3a50ac9903:/bsd/netinet/tcp_output.c diff --git a/bsd/netinet/tcp_output.c b/bsd/netinet/tcp_output.c index c648029c6..75e8634c0 100644 --- a/bsd/netinet/tcp_output.c +++ b/bsd/netinet/tcp_output.c @@ -1,23 +1,29 @@ /* - * Copyright (c) 2000 Apple Computer, Inc. All rights reserved. + * Copyright (c) 2000-2018 Apple Inc. All rights reserved. * - * @APPLE_LICENSE_HEADER_START@ - * - * The contents of this file constitute Original Code as defined in and - * are subject to the Apple Public Source License Version 1.1 (the - * "License"). You may not use this file except in compliance with the - * License. Please obtain a copy of the License at - * http://www.apple.com/publicsource and read it before using this file. - * - * This Original Code and all software distributed under the License are - * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER + * @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 OR NON-INFRINGEMENT. Please see the - * License for the specific language governing rights and limitations - * under the License. - * - * @APPLE_LICENSE_HEADER_END@ + * 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 @@ -52,17 +58,22 @@ * SUCH DAMAGE. * * @(#)tcp_output.c 8.4 (Berkeley) 5/24/95 + * $FreeBSD: src/sys/netinet/tcp_output.c,v 1.39.2.10 2001/07/07 04:30:38 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. */ -#if ISFB31 -#include "opt_tcpdebug.h" -#endif #define _IP_VHL -#include #include #include +#include +#include #include #include #include @@ -70,50 +81,481 @@ #include #include +#include +#include +#include +#include +#include #include #include +#include +#include #include +#include #include +#include #if INET6 +#include #include -#include #include #endif -#include #include #define TCPOUTFLAGS +#include #include #include #include #include #include +#include #if TCPDEBUG #include #endif #include +#include + +#if IPSEC +#include +#endif /*IPSEC*/ + +#if CONFIG_MACF_NET +#include +#endif /* MAC_SOCKET */ + +#include +#if MPTCP +#include +#include +#include +#endif + +#include #define DBG_LAYER_BEG NETDBG_CODE(DBG_NETTCP, 1) #define DBG_LAYER_END NETDBG_CODE(DBG_NETTCP, 3) #define DBG_FNC_TCP_OUTPUT NETDBG_CODE(DBG_NETTCP, (4 << 8) | 1) +SYSCTL_SKMEM_TCP_INT(OID_AUTO, path_mtu_discovery, + CTLFLAG_RW | CTLFLAG_LOCKED, int, path_mtu_discovery, 1, + "Enable Path MTU Discovery"); + +SYSCTL_SKMEM_TCP_INT(OID_AUTO, slowstart_flightsize, + CTLFLAG_RW | CTLFLAG_LOCKED, int, ss_fltsz, 1, + "Slow start flight size"); + +SYSCTL_SKMEM_TCP_INT(OID_AUTO, local_slowstart_flightsize, + CTLFLAG_RW | CTLFLAG_LOCKED, int, ss_fltsz_local, 8, + "Slow start flight size for local networks"); + +int tcp_do_tso = 1; +SYSCTL_INT(_net_inet_tcp, OID_AUTO, tso, CTLFLAG_RW | CTLFLAG_LOCKED, + &tcp_do_tso, 0, "Enable TCP Segmentation Offload"); + +SYSCTL_SKMEM_TCP_INT(OID_AUTO, ecn_setup_percentage, + CTLFLAG_RW | CTLFLAG_LOCKED, int, tcp_ecn_setup_percentage, 100, + "Max ECN setup percentage"); + +static int +sysctl_change_ecn_setting SYSCTL_HANDLER_ARGS +{ +#pragma unused(oidp, arg1, arg2) + int i, err = 0, changed = 0; + struct ifnet *ifp; + + err = sysctl_io_number(req, tcp_ecn_outbound, sizeof(int32_t), + &i, &changed); + if (err != 0 || req->newptr == USER_ADDR_NULL) + return(err); + + if (changed) { + if ((tcp_ecn_outbound == 0 || tcp_ecn_outbound == 1) && + (i == 0 || i == 1)) { + tcp_ecn_outbound = i; + SYSCTL_SKMEM_UPDATE_FIELD(tcp.ecn_initiate_out, tcp_ecn_outbound); + return(err); + } + if (tcp_ecn_outbound == 2 && (i == 0 || i == 1)) { + /* + * Reset ECN enable flags on non-cellular + * interfaces so that the system default will take + * over + */ + ifnet_head_lock_shared(); + TAILQ_FOREACH(ifp, &ifnet_head, if_link) { + if (!IFNET_IS_CELLULAR(ifp)) { + ifnet_lock_exclusive(ifp); + ifp->if_eflags &= ~IFEF_ECN_DISABLE; + ifp->if_eflags &= ~IFEF_ECN_ENABLE; + ifnet_lock_done(ifp); + } + } + ifnet_head_done(); + } else { + /* + * Set ECN enable flags on non-cellular + * interfaces + */ + ifnet_head_lock_shared(); + TAILQ_FOREACH(ifp, &ifnet_head, if_link) { + if (!IFNET_IS_CELLULAR(ifp)) { + ifnet_lock_exclusive(ifp); + ifp->if_eflags |= IFEF_ECN_ENABLE; + ifp->if_eflags &= ~IFEF_ECN_DISABLE; + ifnet_lock_done(ifp); + } + } + ifnet_head_done(); + } + tcp_ecn_outbound = i; + SYSCTL_SKMEM_UPDATE_FIELD(tcp.ecn_initiate_out, tcp_ecn_outbound); + } + /* Change the other one too as the work is done */ + if (i == 2 || tcp_ecn_inbound == 2) { + tcp_ecn_inbound = i; + SYSCTL_SKMEM_UPDATE_FIELD(tcp.ecn_negotiate_in, tcp_ecn_inbound); + } + return (err); +} + +int tcp_ecn_outbound = 2; +SYSCTL_PROC(_net_inet_tcp, OID_AUTO, ecn_initiate_out, + CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_LOCKED, &tcp_ecn_outbound, 0, + sysctl_change_ecn_setting, "IU", + "Initiate ECN for outbound connections"); + +int tcp_ecn_inbound = 2; +SYSCTL_PROC(_net_inet_tcp, OID_AUTO, ecn_negotiate_in, + CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_LOCKED, &tcp_ecn_inbound, 0, + sysctl_change_ecn_setting, "IU", + "Initiate ECN for inbound connections"); + +SYSCTL_SKMEM_TCP_INT(OID_AUTO, packetchain, + CTLFLAG_RW | CTLFLAG_LOCKED, int, tcp_packet_chaining, 50, + "Enable TCP output packet chaining"); + +SYSCTL_SKMEM_TCP_INT(OID_AUTO, socket_unlocked_on_output, + CTLFLAG_RW | CTLFLAG_LOCKED, int, tcp_output_unlocked, 1, + "Unlock TCP when sending packets down to IP"); + +SYSCTL_SKMEM_TCP_INT(OID_AUTO, rfc3390, + CTLFLAG_RW | CTLFLAG_LOCKED, int, tcp_do_rfc3390, 1, + "Calculate intial slowstart cwnd depending on MSS"); + +SYSCTL_SKMEM_TCP_INT(OID_AUTO, min_iaj_win, + CTLFLAG_RW | CTLFLAG_LOCKED, int, tcp_min_iaj_win, MIN_IAJ_WIN, + "Minimum recv win based on inter-packet arrival jitter"); + +SYSCTL_SKMEM_TCP_INT(OID_AUTO, acc_iaj_react_limit, + CTLFLAG_RW | CTLFLAG_LOCKED, int, tcp_acc_iaj_react_limit, + ACC_IAJ_REACT_LIMIT, "Accumulated IAJ when receiver starts to react"); + +SYSCTL_SKMEM_TCP_INT(OID_AUTO, doautosndbuf, + CTLFLAG_RW | CTLFLAG_LOCKED, uint32_t, tcp_do_autosendbuf, 1, + "Enable send socket buffer auto-tuning"); + +SYSCTL_SKMEM_TCP_INT(OID_AUTO, autosndbufinc, + CTLFLAG_RW | CTLFLAG_LOCKED, uint32_t, tcp_autosndbuf_inc, + 8 * 1024, "Increment in send socket bufffer size"); + +SYSCTL_SKMEM_TCP_INT(OID_AUTO, autosndbufmax, + CTLFLAG_RW | CTLFLAG_LOCKED, uint32_t, tcp_autosndbuf_max, 512 * 1024, + "Maximum send socket buffer size"); + +SYSCTL_SKMEM_TCP_INT(OID_AUTO, ack_prioritize, + CTLFLAG_RW | CTLFLAG_LOCKED, uint32_t, tcp_prioritize_acks, 1, + "Prioritize pure acks"); -#ifdef notyet -extern struct mbuf *m_copypack(); +SYSCTL_SKMEM_TCP_INT(OID_AUTO, rtt_recvbg, + CTLFLAG_RW | CTLFLAG_LOCKED, uint32_t, tcp_use_rtt_recvbg, 1, + "Use RTT for bg recv algorithm"); + +SYSCTL_SKMEM_TCP_INT(OID_AUTO, recv_throttle_minwin, + CTLFLAG_RW | CTLFLAG_LOCKED, uint32_t, tcp_recv_throttle_minwin, 16 * 1024, + "Minimum recv win for throttling"); + +SYSCTL_SKMEM_TCP_INT(OID_AUTO, enable_tlp, + CTLFLAG_RW | CTLFLAG_LOCKED, + int32_t, tcp_enable_tlp, 1, "Enable Tail loss probe"); + +static int32_t packchain_newlist = 0; +static int32_t packchain_looped = 0; +static int32_t packchain_sent = 0; + +/* temporary: for testing */ +#if IPSEC +extern int ipsec_bypass; #endif +extern int slowlink_wsize; /* window correction for slow links */ +#if IPFIREWALL +extern int fw_enable; /* firewall check for packet chaining */ +extern int fw_bypass; /* firewall check: disable packet chaining if there is rules */ +#endif /* IPFIREWALL */ + +extern u_int32_t dlil_filter_disable_tso_count; +extern u_int32_t kipf_count; + +static int tcp_ip_output(struct socket *, struct tcpcb *, struct mbuf *, + int, struct mbuf *, int, int, boolean_t); +static struct mbuf* tcp_send_lroacks(struct tcpcb *tp, struct mbuf *m, struct tcphdr *th); +static int tcp_recv_throttle(struct tcpcb *tp); + +static int32_t tcp_tfo_check(struct tcpcb *tp, int32_t len) +{ + struct socket *so = tp->t_inpcb->inp_socket; + unsigned int optlen = 0; + unsigned int cookie_len; + + if (tp->t_flags & TF_NOOPT) + goto fallback; + + if ((so->so_flags1 & SOF1_DATA_AUTHENTICATED) && + !(tp->t_flagsext & TF_FASTOPEN_HEUR)) + return (len); + + if (!tcp_heuristic_do_tfo(tp)) { + tp->t_tfo_stats |= TFO_S_HEURISTICS_DISABLE; + tcpstat.tcps_tfo_heuristics_disable++; + goto fallback; + } + + if (so->so_flags1 & SOF1_DATA_AUTHENTICATED) + return (len); + + optlen += TCPOLEN_MAXSEG; + + if (tp->t_flags & TF_REQ_SCALE) + optlen += 4; + +#if MPTCP + if ((so->so_flags & SOF_MP_SUBFLOW) && mptcp_enable && + tp->t_rxtshift <= mptcp_mpcap_retries) + optlen += sizeof(struct mptcp_mpcapable_opt_common) + sizeof(mptcp_key_t); +#endif /* MPTCP */ + + if (tp->t_flags & TF_REQ_TSTMP) + optlen += TCPOLEN_TSTAMP_APPA; + + if (SACK_ENABLED(tp)) + optlen += TCPOLEN_SACK_PERMITTED; + + /* Now, decide whether to use TFO or not */ + + /* Don't even bother trying if there is no space at all... */ + if (MAX_TCPOPTLEN - optlen < TCPOLEN_FASTOPEN_REQ) + goto fallback; + + cookie_len = tcp_cache_get_cookie_len(tp); + if (cookie_len == 0) + /* No cookie, so we request one */ + return (0); + + /* There is not enough space for the cookie, so we cannot do TFO */ + if (MAX_TCPOPTLEN - optlen < cookie_len) + goto fallback; + + /* Do not send SYN+data if there is more in the queue than MSS */ + if (so->so_snd.sb_cc > (tp->t_maxopd - MAX_TCPOPTLEN)) + goto fallback; + + /* Ok, everything looks good. We can go on and do TFO */ + return (len); + +fallback: + tp->t_flagsext &= ~TF_FASTOPEN; + return (0); +} + +/* Returns the number of bytes written to the TCP option-space */ +static unsigned +tcp_tfo_write_cookie_rep(struct tcpcb *tp, unsigned optlen, u_char *opt) +{ + u_char out[CCAES_BLOCK_SIZE]; + unsigned ret = 0; + u_char *bp; + + if ((MAX_TCPOPTLEN - optlen) < + (TCPOLEN_FASTOPEN_REQ + TFO_COOKIE_LEN_DEFAULT)) + return (ret); + + tcp_tfo_gen_cookie(tp->t_inpcb, out, sizeof(out)); + + bp = opt + optlen; + + *bp++ = TCPOPT_FASTOPEN; + *bp++ = 2 + TFO_COOKIE_LEN_DEFAULT; + memcpy(bp, out, TFO_COOKIE_LEN_DEFAULT); + ret += 2 + TFO_COOKIE_LEN_DEFAULT; + + tp->t_tfo_stats |= TFO_S_COOKIE_SENT; + tcpstat.tcps_tfo_cookie_sent++; + + return (ret); +} + +static unsigned +tcp_tfo_write_cookie(struct tcpcb *tp, unsigned optlen, int32_t len, + u_char *opt) +{ + u_int8_t tfo_len = MAX_TCPOPTLEN - optlen - TCPOLEN_FASTOPEN_REQ; + struct socket *so = tp->t_inpcb->inp_socket; + unsigned ret = 0; + int res; + u_char *bp; + + if (so->so_flags1 & SOF1_DATA_AUTHENTICATED) { + /* If there is some data, let's track it */ + if (len > 0) { + tp->t_tfo_stats |= TFO_S_SYN_DATA_SENT; + tcpstat.tcps_tfo_syn_data_sent++; + } + + return (0); + } + + bp = opt + optlen; + + /* + * The cookie will be copied in the appropriate place within the + * TCP-option space. That way we avoid the need for an intermediate + * variable. + */ + res = tcp_cache_get_cookie(tp, bp + TCPOLEN_FASTOPEN_REQ, &tfo_len); + if (res == 0) { + *bp++ = TCPOPT_FASTOPEN; + *bp++ = TCPOLEN_FASTOPEN_REQ; + ret += TCPOLEN_FASTOPEN_REQ; + + tp->t_tfo_flags |= TFO_F_COOKIE_REQ; + + tp->t_tfo_stats |= TFO_S_COOKIE_REQ; + tcpstat.tcps_tfo_cookie_req++; + } else { + *bp++ = TCPOPT_FASTOPEN; + *bp++ = TCPOLEN_FASTOPEN_REQ + tfo_len; + + ret += TCPOLEN_FASTOPEN_REQ + tfo_len; + + tp->t_tfo_flags |= TFO_F_COOKIE_SENT; + + /* If there is some data, let's track it */ + if (len > 0) { + tp->t_tfo_stats |= TFO_S_SYN_DATA_SENT; + tcpstat.tcps_tfo_syn_data_sent++; + } + } + + return (ret); +} + +static inline bool +tcp_send_ecn_flags_on_syn(struct tcpcb *tp, struct socket *so) +{ + return(!((tp->ecn_flags & TE_SETUPSENT) || + (so->so_flags & SOF_MP_SUBFLOW) || + (tp->t_flagsext & TF_FASTOPEN))); +} + +void +tcp_set_ecn(struct tcpcb *tp, struct ifnet *ifp) +{ + boolean_t inbound; + + /* + * Socket option has precedence + */ + if (tp->ecn_flags & TE_ECN_MODE_ENABLE) { + tp->ecn_flags |= TE_ENABLE_ECN; + goto check_heuristic; + } + + if (tp->ecn_flags & TE_ECN_MODE_DISABLE) { + tp->ecn_flags &= ~TE_ENABLE_ECN; + return; + } + /* + * Per interface setting comes next + */ + if (ifp != NULL) { + if (ifp->if_eflags & IFEF_ECN_ENABLE) { + tp->ecn_flags |= TE_ENABLE_ECN; + goto check_heuristic; + } + + if (ifp->if_eflags & IFEF_ECN_DISABLE) { + tp->ecn_flags &= ~TE_ENABLE_ECN; + return; + } + } + /* + * System wide settings come last + */ + inbound = (tp->t_inpcb->inp_socket->so_head != NULL); + if ((inbound && tcp_ecn_inbound == 1) || + (!inbound && tcp_ecn_outbound == 1)) { + tp->ecn_flags |= TE_ENABLE_ECN; + goto check_heuristic; + } else { + tp->ecn_flags &= ~TE_ENABLE_ECN; + } + + return; + +check_heuristic: + if (!tcp_heuristic_do_ecn(tp)) + tp->ecn_flags &= ~TE_ENABLE_ECN; + + /* + * If the interface setting, system-level setting and heuristics + * allow to enable ECN, randomly select 5% of connections to + * enable it + */ + if ((tp->ecn_flags & (TE_ECN_MODE_ENABLE | TE_ECN_MODE_DISABLE + | TE_ENABLE_ECN)) == TE_ENABLE_ECN) { + /* + * Use the random value in iss for randomizing + * this selection + */ + if ((tp->iss % 100) >= tcp_ecn_setup_percentage) + tp->ecn_flags &= ~TE_ENABLE_ECN; + } +} /* * Tcp output routine: figure out what should be sent and send it. + * + * Returns: 0 Success + * EADDRNOTAVAIL + * ENOBUFS + * EMSGSIZE + * EHOSTUNREACH + * ENETDOWN + * ip_output_list:ENOMEM + * ip_output_list:EADDRNOTAVAIL + * ip_output_list:ENETUNREACH + * ip_output_list:EHOSTUNREACH + * ip_output_list:EACCES + * ip_output_list:EMSGSIZE + * ip_output_list:ENOBUFS + * ip_output_list:??? [ignorable: mostly IPSEC/firewall/DLIL] + * ip6_output_list:EINVAL + * ip6_output_list:EOPNOTSUPP + * ip6_output_list:EHOSTUNREACH + * ip6_output_list:EADDRNOTAVAIL + * ip6_output_list:ENETUNREACH + * ip6_output_list:EMSGSIZE + * ip6_output_list:ENOBUFS + * ip6_output_list:??? [ignorable: mostly IPSEC/firewall/DLIL] */ int -tcp_output(tp) - register struct tcpcb *tp; +tcp_output(struct tcpcb *tp) { - register struct socket *so = tp->t_inpcb->inp_socket; - register long len, win; - int off, flags, error; - register struct mbuf *m; + struct inpcb *inp = tp->t_inpcb; + struct socket *so = inp->inp_socket; + int32_t len, recwin, sendwin, off; + int flags, error; + struct mbuf *m; struct ip *ip = NULL; struct ipovly *ipov = NULL; #if INET6 @@ -122,19 +564,38 @@ tcp_output(tp) struct tcphdr *th; u_char opt[TCP_MAXOLEN]; unsigned ipoptlen, optlen, hdrlen; - int idle, sendalot; - struct rmxp_tao *taop; - struct rmxp_tao tao_noncached; + int idle, sendalot, lost = 0; + int i, sack_rxmit; + int tso = 0; + int sack_bytes_rxmt; + tcp_seq old_snd_nxt = 0; + struct sackhole *p; +#if IPSEC + unsigned ipsec_optlen = 0; +#endif /* IPSEC */ + int idle_time = 0; + struct mbuf *packetlist = NULL; + struct mbuf *tp_inp_options = inp->inp_depend4.inp4_options; #if INET6 - int isipv6 = (tp->t_inpcb->inp_vflag & INP_IPV4) == 0; + int isipv6 = inp->inp_vflag & INP_IPV6 ; +#else + int isipv6 = 0; #endif - - KERNEL_DEBUG(DBG_FNC_TCP_OUTPUT | DBG_FUNC_START, 0,0,0,0,0); - KERNEL_DEBUG(DBG_LAYER_BEG, - ((tp->t_template->tt_dport << 16) | tp->t_template->tt_sport), - (((tp->t_template->tt_src.s_addr & 0xffff) << 16) | - (tp->t_template->tt_dst.s_addr & 0xffff)), - 0,0,0); + short packchain_listadd = 0; + int so_options = so->so_options; + struct rtentry *rt; + u_int32_t svc_flags = 0, allocated_len; + u_int32_t lro_ackmore = (tp->t_lropktlen != 0) ? 1 : 0; + struct mbuf *mnext = NULL; + int sackoptlen = 0; +#if MPTCP + boolean_t mptcp_acknow; +#endif /* MPTCP */ + boolean_t cell = FALSE; + boolean_t wifi = FALSE; + boolean_t wired = FALSE; + boolean_t sack_rescue_rxt = FALSE; + int sotc = so->so_traffic_class; /* * Determine length of data that should be transmitted, @@ -142,24 +603,257 @@ tcp_output(tp) * If there is some data or critical controls (SYN, RST) * to send, then transmit; otherwise, investigate further. */ - idle = (tp->snd_max == tp->snd_una); - if (idle && tp->t_idle >= tp->t_rxtcur) + idle = (tp->t_flags & TF_LASTIDLE) || (tp->snd_max == tp->snd_una); + + /* Since idle_time is signed integer, the following integer subtraction + * will take care of wrap around of tcp_now + */ + idle_time = tcp_now - tp->t_rcvtime; + if (idle && idle_time >= TCP_IDLETIMEOUT(tp)) { + if (CC_ALGO(tp)->after_idle != NULL && + (tp->tcp_cc_index != TCP_CC_ALGO_CUBIC_INDEX || + idle_time >= TCP_CC_CWND_NONVALIDATED_PERIOD)) { + CC_ALGO(tp)->after_idle(tp); + tcp_ccdbg_trace(tp, NULL, TCP_CC_IDLE_TIMEOUT); + } + + /* + * Do some other tasks that need to be done after + * idle time + */ + if (!SLIST_EMPTY(&tp->t_rxt_segments)) + tcp_rxtseg_clean(tp); + + /* If stretch ack was auto-disabled, re-evaluate it */ + tcp_cc_after_idle_stretchack(tp); + } + tp->t_flags &= ~TF_LASTIDLE; + if (idle) { + if (tp->t_flags & TF_MORETOCOME) { + tp->t_flags |= TF_LASTIDLE; + idle = 0; + } + } +#if MPTCP + if (tp->t_mpflags & TMPF_RESET) { + tcp_check_timer_state(tp); /* - * We have been idle for "a while" and no acks are - * expected to clock out any data we send -- - * slow start to get ack "clock" running again. + * Once a RST has been sent for an MPTCP subflow, + * the subflow socket stays around until deleted. + * No packets such as FINs must be sent after RST. */ - tp->snd_cwnd = tp->t_maxseg; - - /* Never send data that's already been acked */ - if (SEQ_GT(tp->snd_una, tp->snd_nxt)) - tp->snd_nxt = tp->snd_una; + return (0); + } +#endif /* MPTCP */ + again: +#if MPTCP + mptcp_acknow = FALSE; +#endif + + KERNEL_DEBUG(DBG_FNC_TCP_OUTPUT | DBG_FUNC_START, 0,0,0,0,0); + +#if INET6 + if (isipv6) { + KERNEL_DEBUG(DBG_LAYER_BEG, + ((inp->inp_fport << 16) | inp->inp_lport), + (((inp->in6p_laddr.s6_addr16[0] & 0xffff) << 16) | + (inp->in6p_faddr.s6_addr16[0] & 0xffff)), + sendalot,0,0); + } else +#endif + + { + KERNEL_DEBUG(DBG_LAYER_BEG, + ((inp->inp_fport << 16) | inp->inp_lport), + (((inp->inp_laddr.s_addr & 0xffff) << 16) | + (inp->inp_faddr.s_addr & 0xffff)), + sendalot,0,0); + } + /* + * If the route generation id changed, we need to check that our + * local (source) IP address is still valid. If it isn't either + * return error or silently do nothing (assuming the address will + * come back before the TCP connection times out). + */ + rt = inp->inp_route.ro_rt; + if (rt != NULL && ROUTE_UNUSABLE(&tp->t_inpcb->inp_route)) { + struct ifnet *ifp; + struct in_ifaddr *ia = NULL; + struct in6_ifaddr *ia6 = NULL; + int found_srcaddr = 0; + + /* disable multipages at the socket */ + somultipages(so, FALSE); + + /* Disable TSO for the socket until we know more */ + tp->t_flags &= ~TF_TSO; + + soif2kcl(so, FALSE); + + if (isipv6) { + ia6 = ifa_foraddr6(&inp->in6p_laddr); + if (ia6 != NULL) + found_srcaddr = 1; + } else { + ia = ifa_foraddr(inp->inp_laddr.s_addr); + if (ia != NULL) + found_srcaddr = 1; + } + + /* check that the source address is still valid */ + if (found_srcaddr == 0) { + soevent(so, + (SO_FILT_HINT_LOCKED | SO_FILT_HINT_NOSRCADDR)); + + if (tp->t_state >= TCPS_CLOSE_WAIT) { + tcp_drop(tp, EADDRNOTAVAIL); + return(EADDRNOTAVAIL); + } + + /* Set retransmit timer if it wasn't set, + * reset Persist timer and shift register as the + * advertised peer window may not be valid anymore + */ + + if (!tp->t_timer[TCPT_REXMT]) { + tp->t_timer[TCPT_REXMT] = + OFFSET_FROM_START(tp, tp->t_rxtcur); + if (tp->t_timer[TCPT_PERSIST]) { + tp->t_timer[TCPT_PERSIST] = 0; + tp->t_persist_stop = 0; + TCP_RESET_REXMT_STATE(tp); + } + } + + if (tp->t_pktlist_head != NULL) + m_freem_list(tp->t_pktlist_head); + TCP_PKTLIST_CLEAR(tp); + + /* drop connection if source address isn't available */ + if (so->so_flags & SOF_NOADDRAVAIL) { + tcp_drop(tp, EADDRNOTAVAIL); + return(EADDRNOTAVAIL); + } else { + tcp_check_timer_state(tp); + return(0); /* silently ignore, keep data in socket: address may be back */ + } + } + if (ia != NULL) + IFA_REMREF(&ia->ia_ifa); + + if (ia6 != NULL) + IFA_REMREF(&ia6->ia_ifa); + + /* + * Address is still valid; check for multipages capability + * again in case the outgoing interface has changed. + */ + RT_LOCK(rt); + if ((ifp = rt->rt_ifp) != NULL) { + somultipages(so, (ifp->if_hwassist & IFNET_MULTIPAGES)); + tcp_set_tso(tp, ifp); + soif2kcl(so, (ifp->if_eflags & IFEF_2KCL)); + tcp_set_ecn(tp, ifp); + } + if (rt->rt_flags & RTF_UP) + RT_GENID_SYNC(rt); + /* + * See if we should do MTU discovery. 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; + + RT_UNLOCK(rt); + } + + if (rt != NULL) { + cell = IFNET_IS_CELLULAR(rt->rt_ifp); + wifi = (!cell && IFNET_IS_WIFI(rt->rt_ifp)); + wired = (!wifi && IFNET_IS_WIRED(rt->rt_ifp)); + } + + /* + * If we've recently taken a timeout, snd_max will be greater than + * snd_nxt. There may be SACK information that allows us to avoid + * resending already delivered data. Adjust snd_nxt accordingly. + */ + if (SACK_ENABLED(tp) && SEQ_LT(tp->snd_nxt, tp->snd_max)) + tcp_sack_adjust(tp); sendalot = 0; off = tp->snd_nxt - tp->snd_una; - win = min(tp->snd_wnd, tp->snd_cwnd); + sendwin = min(tp->snd_wnd, tp->snd_cwnd); + + if (tp->t_flags & TF_SLOWLINK && slowlink_wsize > 0) + sendwin = min(sendwin, slowlink_wsize); flags = tcp_outflags[tp->t_state]; + /* + * Send any SACK-generated retransmissions. If we're explicitly + * trying to send out new data (when sendalot is 1), bypass this + * function. If we retransmit in fast recovery mode, decrement + * snd_cwnd, since we're replacing a (future) new transmission + * with a retransmission now, and we previously incremented + * snd_cwnd in tcp_input(). + */ + /* + * Still in sack recovery , reset rxmit flag to zero. + */ + sack_rxmit = 0; + sack_bytes_rxmt = 0; + len = 0; + p = NULL; + if (SACK_ENABLED(tp) && IN_FASTRECOVERY(tp) && + (p = tcp_sack_output(tp, &sack_bytes_rxmt))) { + int32_t cwin; + + cwin = min(tp->snd_wnd, tp->snd_cwnd) - sack_bytes_rxmt; + if (cwin < 0) + cwin = 0; + /* Do not retransmit SACK segments beyond snd_recover */ + if (SEQ_GT(p->end, tp->snd_recover)) { + /* + * (At least) part of sack hole extends beyond + * snd_recover. Check to see if we can rexmit data + * for this hole. + */ + if (SEQ_GEQ(p->rxmit, tp->snd_recover)) { + /* + * Can't rexmit any more data for this hole. + * That data will be rexmitted in the next + * sack recovery episode, when snd_recover + * moves past p->rxmit. + */ + p = NULL; + goto after_sack_rexmit; + } else + /* Can rexmit part of the current hole */ + len = ((int32_t)min(cwin, + tp->snd_recover - p->rxmit)); + } else { + len = ((int32_t)min(cwin, p->end - p->rxmit)); + } + if (len > 0) { + off = p->rxmit - tp->snd_una; + sack_rxmit = 1; + sendalot = 1; + tcpstat.tcps_sack_rexmits++; + tcpstat.tcps_sack_rexmit_bytes += + min(len, tp->t_maxseg); + } else { + len = 0; + } + } +after_sack_rexmit: /* * Get standard flags, and add SYN or FIN if requested by 'hidden' * state flags. @@ -175,8 +869,8 @@ again: * and timer expired, we will send what we can * and go to transmit state. */ - if (tp->t_force) { - if (win == 0) { + if (tp->t_flagsext & TF_FORCE) { + if (sendwin == 0) { /* * If we still have some data to send, then * clear the FIN bit. Usually this would @@ -195,18 +889,88 @@ again: */ if (off < so->so_snd.sb_cc) flags &= ~TH_FIN; - win = 1; + sendwin = 1; } else { tp->t_timer[TCPT_PERSIST] = 0; - tp->t_rxtshift = 0; + tp->t_persist_stop = 0; + TCP_RESET_REXMT_STATE(tp); } } - len = (long)ulmin(so->so_snd.sb_cc, win) - off; + /* + * If snd_nxt == snd_max and we have transmitted a FIN, the + * offset will be > 0 even if so_snd.sb_cc is 0, resulting in + * a negative length. This can also occur when TCP opens up + * its congestion window while receiving additional duplicate + * acks after fast-retransmit because TCP will reset snd_nxt + * to snd_max after the fast-retransmit. + * + * In the normal retransmit-FIN-only case, however, snd_nxt will + * be set to snd_una, the offset will be 0, and the length may + * wind up 0. + * + * If sack_rxmit is true we are retransmitting from the scoreboard + * in which case len is already set. + */ + if (sack_rxmit == 0) { + if (sack_bytes_rxmt == 0) { + len = min(so->so_snd.sb_cc, sendwin) - off; + } else { + int32_t cwin; + + cwin = tp->snd_cwnd - + (tp->snd_nxt - tp->sack_newdata) - + sack_bytes_rxmt; + if (cwin < 0) + cwin = 0; + /* + * We are inside of a SACK recovery episode and are + * sending new data, having retransmitted all the + * data possible in the scoreboard. + */ + len = min(so->so_snd.sb_cc, tp->snd_wnd) + - off; + /* + * Don't remove this (len > 0) check ! + * We explicitly check for len > 0 here (although it + * isn't really necessary), to work around a gcc + * optimization issue - to force gcc to compute + * len above. Without this check, the computation + * of len is bungled by the optimizer. + */ + if (len > 0) { + len = imin(len, cwin); + } else { + len = 0; + } + /* + * At this point SACK recovery can not send any + * data from scoreboard or any new data. Check + * if we can do a rescue retransmit towards the + * tail end of recovery window. + */ + if (len == 0 && cwin > 0 && + SEQ_LT(tp->snd_fack, tp->snd_recover) && + !(tp->t_flagsext & TF_RESCUE_RXT)) { + len = min((tp->snd_recover - tp->snd_fack), + tp->t_maxseg); + len = imin(len, cwin); + old_snd_nxt = tp->snd_nxt; + sack_rescue_rxt = TRUE; + tp->snd_nxt = tp->snd_recover - len; + /* + * If FIN has been sent, snd_max + * must have been advanced to cover it. + */ + if ((tp->t_flags & TF_SENTFIN) && + tp->snd_max == tp->snd_recover) + tp->snd_nxt--; - if ((taop = tcp_gettaocache(tp->t_inpcb)) == NULL) { - taop = &tao_noncached; - bzero(taop, sizeof(*taop)); + off = tp->snd_nxt - tp->snd_una; + sendalot = 0; + tp->t_flagsext |= TF_RESCUE_RXT; + } + } } /* @@ -215,33 +979,70 @@ again: * know that foreign host supports TAO, suppress sending segment. */ if ((flags & TH_SYN) && SEQ_GT(tp->snd_nxt, tp->snd_una)) { - flags &= ~TH_SYN; - off--, len++; - if (len > 0 && tp->t_state == TCPS_SYN_SENT && - taop->tao_ccsent == 0) { - KERNEL_DEBUG(DBG_FNC_TCP_OUTPUT | DBG_FUNC_END, 0,0,0,0,0); - return 0; + if (tp->t_state != TCPS_SYN_RECEIVED || tfo_enabled(tp)) + flags &= ~TH_SYN; + off--; + len++; + if (len > 0 && tp->t_state == TCPS_SYN_SENT) { + while (inp->inp_sndinprog_cnt == 0 && + tp->t_pktlist_head != NULL) { + packetlist = tp->t_pktlist_head; + packchain_listadd = tp->t_lastchain; + packchain_sent++; + TCP_PKTLIST_CLEAR(tp); + + error = tcp_ip_output(so, tp, packetlist, + packchain_listadd, tp_inp_options, + (so_options & SO_DONTROUTE), + (sack_rxmit || (sack_bytes_rxmt != 0)), + isipv6); + } + + /* + * tcp was closed while we were in ip, + * resume close + */ + if (inp->inp_sndinprog_cnt == 0 && + (tp->t_flags & TF_CLOSING)) { + tp->t_flags &= ~TF_CLOSING; + (void) tcp_close(tp); + } else { + tcp_check_timer_state(tp); + } + KERNEL_DEBUG(DBG_FNC_TCP_OUTPUT | DBG_FUNC_END, + 0,0,0,0,0); + return(0); } } /* - * Be careful not to send data and/or FIN on SYN segments - * in cases when no CC option will be sent. + * Be careful not to send data and/or FIN on SYN segments. * This measure is needed to prevent interoperability problems * with not fully conformant TCP implementations. + * + * In case of TFO, we handle the setting of the len in + * tcp_tfo_check. In case TFO is not enabled, never ever send + * SYN+data. */ - if ((flags & TH_SYN) && - ((tp->t_flags & TF_NOOPT) || !(tp->t_flags & TF_REQ_CC) || - ((flags & TH_ACK) && !(tp->t_flags & TF_RCVD_CC)))) { + if ((flags & TH_SYN) && !tfo_enabled(tp)) { len = 0; flags &= ~TH_FIN; } - if (len < 0) { + if ((flags & TH_SYN) && tp->t_state <= TCPS_SYN_SENT && tfo_enabled(tp)) + len = tcp_tfo_check(tp, len); + + /* + * The check here used to be (len < 0). Some times len is zero + * when the congestion window is closed and we need to check + * if persist timer has to be set in that case. But don't set + * persist until connection is established. + */ + if (len <= 0 && !(flags & TH_SYN)) { /* * If FIN has been sent but not acked, * but we haven't been called to retransmit, - * len will be -1. Otherwise, window shrank + * len will be < 0. Otherwise, window shrank * after we sent into it. If window shrank to 0, * cancel pending retransmit, pull snd_nxt back * to (closed) window, and set the persist timer @@ -249,73 +1050,320 @@ again: * close completely, just wait for an ACK. */ len = 0; - if (win == 0) { + if (sendwin == 0) { tp->t_timer[TCPT_REXMT] = 0; - tp->t_rxtshift = 0; + tp->t_timer[TCPT_PTO] = 0; + TCP_RESET_REXMT_STATE(tp); tp->snd_nxt = tp->snd_una; + off = 0; if (tp->t_timer[TCPT_PERSIST] == 0) tcp_setpersist(tp); } } - if (len > tp->t_maxseg) { - len = tp->t_maxseg; - sendalot = 1; - } - if (SEQ_LT(tp->snd_nxt + len, tp->snd_una + so->so_snd.sb_cc)) - flags &= ~TH_FIN; - - win = sbspace(&so->so_rcv); /* - * Sender silly window avoidance. If connection is idle - * and can send all data, a maximum segment, - * at least a maximum default-size segment do it, - * or are forced, do it; otherwise don't bother. - * If peer's buffer is tiny, then send - * when window is at least half open. - * If retransmitting (possibly after persist timer forced us - * to send into a small window), then must resend. + * Automatic sizing of send socket buffer. Increase the send + * socket buffer size if all of the following criteria are met + * 1. the receiver has enough buffer space for this data + * 2. send buffer is filled to 7/8th with data (so we actually + * have data to make use of it); + * 3. our send window (slow start and congestion controlled) is + * larger than sent but unacknowledged data in send buffer. */ - if (len) { - if (len == tp->t_maxseg) - goto send; - if (!(tp->t_flags & TF_MORETOCOME) && - (idle || tp->t_flags & TF_NODELAY) && - (tp->t_flags & TF_NOPUSH) == 0 && - len + off >= so->so_snd.sb_cc) - goto send; - if (tp->t_force) - goto send; - if (len >= tp->max_sndwnd / 2 && tp->max_sndwnd > 0) - goto send; - if (SEQ_LT(tp->snd_nxt, tp->snd_max)) - goto send; + if (tcp_do_autosendbuf == 1 && + !INP_WAIT_FOR_IF_FEEDBACK(inp) && !IN_FASTRECOVERY(tp) && + (so->so_snd.sb_flags & (SB_AUTOSIZE | SB_TRIM)) == SB_AUTOSIZE && + tcp_cansbgrow(&so->so_snd)) { + if ((tp->snd_wnd / 4 * 5) >= so->so_snd.sb_hiwat && + so->so_snd.sb_cc >= (so->so_snd.sb_hiwat / 8 * 7) && + sendwin >= (so->so_snd.sb_cc - (tp->snd_nxt - tp->snd_una))) { + if (sbreserve(&so->so_snd, + min(so->so_snd.sb_hiwat + tcp_autosndbuf_inc, + tcp_autosndbuf_max)) == 1) { + so->so_snd.sb_idealsize = so->so_snd.sb_hiwat; + } + } } /* - * Compare available window to amount of window - * known to peer (as advertised window less - * next expected input). If the difference is at least two - * max size segments, or at least 50% of the maximum possible - * window, then want to send a window update to peer. - */ - if (win > 0) { + * Truncate to the maximum segment length or enable TCP Segmentation + * Offloading (if supported by hardware) and ensure that FIN is removed + * if the length no longer contains the last data byte. + * + * TSO may only be used if we are in a pure bulk sending state. + * The presence of TCP-MD5, SACK retransmits, SACK advertizements, + * ipfw rules and IP options, as well as disabling hardware checksum + * offload prevent using TSO. With TSO the TCP header is the same + * (except for the sequence number) for all generated packets. This + * makes it impossible to transmit any options which vary per generated + * segment or packet. + * + * The length of TSO bursts is limited to TCP_MAXWIN. That limit and + * removal of FIN (if not already catched here) are handled later after + * the exact length of the TCP options are known. + */ +#if IPSEC + /* + * Pre-calculate here as we save another lookup into the darknesses + * of IPsec that way and can actually decide if TSO is ok. + */ + if (ipsec_bypass == 0) + ipsec_optlen = ipsec_hdrsiz_tcp(tp); +#endif + if (len > tp->t_maxseg) { + if ((tp->t_flags & TF_TSO) && tcp_do_tso && hwcksum_tx && + ip_use_randomid && kipf_count == 0 && + dlil_filter_disable_tso_count == 0 && + tp->rcv_numsacks == 0 && sack_rxmit == 0 && + sack_bytes_rxmt == 0 && + inp->inp_options == NULL && + inp->in6p_options == NULL +#if IPSEC + && ipsec_optlen == 0 +#endif +#if IPFIREWALL + && (fw_enable == 0 || fw_bypass) +#endif + ) { + tso = 1; + sendalot = 0; + } else { + len = tp->t_maxseg; + sendalot = 1; + tso = 0; + } + } + + /* Send one segment or less as a tail loss probe */ + if (tp->t_flagsext & TF_SENT_TLPROBE) { + len = min(len, tp->t_maxseg); + sendalot = 0; + tso = 0; + } + +#if MPTCP + if ((so->so_flags & SOF_MP_SUBFLOW) && + !(tp->t_mpflags & TMPF_TCP_FALLBACK)) { + int newlen = len; + if (tp->t_state >= TCPS_ESTABLISHED && + (tp->t_mpflags & TMPF_SND_MPPRIO || + tp->t_mpflags & TMPF_SND_REM_ADDR || + tp->t_mpflags & TMPF_SND_MPFAIL || + tp->t_mpflags & TMPF_SND_KEYS || + tp->t_mpflags & TMPF_SND_JACK)) { + if (len > 0) { + len = 0; + } + /* + * On a new subflow, don't try to send again, because + * we are still waiting for the fourth ack. + */ + if (!(tp->t_mpflags & TMPF_PREESTABLISHED)) + sendalot = 1; + mptcp_acknow = TRUE; + } else { + mptcp_acknow = FALSE; + } + /* + * The contiguous bytes in the subflow socket buffer can be + * discontiguous at the MPTCP level. Since only one DSS + * option can be sent in one packet, reduce length to match + * the contiguous MPTCP level. Set sendalot to send remainder. + */ + if (len > 0) + newlen = mptcp_adj_sendlen(so, off); + if (newlen < len) { + len = newlen; + sendalot = 1; + } + } +#endif /* MPTCP */ + + /* + * If the socket is capable of doing unordered send, + * pull the amount of data that can be sent from the + * unordered priority queues to the serial queue in + * the socket buffer. If bytes are not yet available + * in the highest priority message, we may not be able + * to send any new data. + */ + if (so->so_flags & SOF_ENABLE_MSGS) { + if ((off + len) > + so->so_msg_state->msg_serial_bytes) { + sbpull_unordered_data(so, off, len); + + /* check if len needs to be modified */ + if ((off + len) > + so->so_msg_state->msg_serial_bytes) { + len = so->so_msg_state->msg_serial_bytes - off; + if (len <= 0) { + len = 0; + tcpstat.tcps_msg_sndwaithipri++; + } + } + } + } + + if (sack_rxmit) { + if (SEQ_LT(p->rxmit + len, tp->snd_una + so->so_snd.sb_cc)) + flags &= ~TH_FIN; + } else { + if (SEQ_LT(tp->snd_nxt + len, tp->snd_una + so->so_snd.sb_cc)) + flags &= ~TH_FIN; + } + /* + * Compare available window to amount of window + * known to peer (as advertised window less + * next expected input). If the difference is at least two + * max size segments, or at least 25% of the maximum possible + * window, then want to send a window update to peer. + * Skip this if the connection is in T/TCP half-open state. + */ + recwin = tcp_sbspace(tp); +#if MPTCP + if (so->so_flags & SOF_MP_SUBFLOW) { + struct mptcb *mp_tp = tptomptp(tp); + + if (mp_tp != NULL) { + mpte_lock_assert_held(mp_tp->mpt_mpte); + recwin = imin(recwin, mptcp_sbspace(mp_tp)); + } + } +#endif + + if (recwin < (int32_t)(so->so_rcv.sb_hiwat / 4) && + recwin < (int)tp->t_maxseg) + recwin = 0; + +#if TRAFFIC_MGT + if (tcp_recv_bg == 1 || IS_TCP_RECV_BG(so)) { + if (recwin > 0 && tcp_recv_throttle(tp)) { + uint32_t min_iaj_win = tcp_min_iaj_win * tp->t_maxseg; + uint32_t bg_rwintop = tp->rcv_adv; + if (SEQ_LT(bg_rwintop, tp->rcv_nxt + min_iaj_win)) + bg_rwintop = tp->rcv_nxt + min_iaj_win; + recwin = imin((int32_t)(bg_rwintop - tp->rcv_nxt), + recwin); + if (recwin < 0) + recwin = 0; + } + } +#endif /* TRAFFIC_MGT */ + + if (recwin > (int32_t)(TCP_MAXWIN << tp->rcv_scale)) + recwin = (int32_t)(TCP_MAXWIN << tp->rcv_scale); + + /* + * MPTCP needs to be able to announce a smaller window than previously, + * because the other subflow may have filled up the available window- + * space. So we have to be able to go backwards and announce a smaller + * window. + */ + if (!(so->so_flags & SOF_MP_SUBFLOW) && + recwin < (int32_t)(tp->rcv_adv - tp->rcv_nxt)) + recwin = (int32_t)(tp->rcv_adv - tp->rcv_nxt); + + /* + * Sender silly window avoidance. We transmit under the following + * conditions when len is non-zero: + * + * - we've timed out (e.g. persist timer) + * - we need to retransmit + * - We have a full segment (or more with TSO) + * - This is the last buffer in a write()/send() and we are + * either idle or running NODELAY + * - we have more then 1/2 the maximum send window's worth of + * data (receiver may be limited the window size) + */ + if (len) { + if (tp->t_flagsext & TF_FORCE) + goto send; + if (SEQ_LT(tp->snd_nxt, tp->snd_max)) + goto send; + if (sack_rxmit) + goto send; + + /* + * Send new data on the connection only if it is + * not flow controlled + */ + if (!INP_WAIT_FOR_IF_FEEDBACK(inp) || + tp->t_state != TCPS_ESTABLISHED) { + if (len >= tp->t_maxseg) + goto send; + + if (!(tp->t_flags & TF_MORETOCOME) && + (idle || tp->t_flags & TF_NODELAY || + (tp->t_flags & TF_MAXSEGSNT) || + ALLOW_LIMITED_TRANSMIT(tp)) && + (tp->t_flags & TF_NOPUSH) == 0 && + (len + off >= so->so_snd.sb_cc || + /* + * MPTCP needs to respect the DSS-mappings. So, it + * may be sending data that *could* have been + * coalesced, but cannot because of + * mptcp_adj_sendlen(). + */ + so->so_flags & SOF_MP_SUBFLOW)) + goto send; + if (len >= tp->max_sndwnd / 2 && tp->max_sndwnd > 0) + goto send; + } else { + tcpstat.tcps_fcholdpacket++; + } + } + + if (recwin > 0 && !(tp->t_flags & TF_NEEDSYN)) { /* * "adv" is the amount we can increase the window, * taking into account that we are limited by * TCP_MAXWIN << tp->rcv_scale. */ - long adv = min(win, (long)TCP_MAXWIN << tp->rcv_scale) - + int32_t adv, oldwin = 0; + adv = imin(recwin, (int)TCP_MAXWIN << tp->rcv_scale) - (tp->rcv_adv - tp->rcv_nxt); - if (adv >= (long) (2 * tp->t_maxseg)) - goto send; - if (2 * adv >= (long) so->so_rcv.sb_hiwat) + if (SEQ_GT(tp->rcv_adv, tp->rcv_nxt)) + oldwin = tp->rcv_adv - tp->rcv_nxt; + + if (adv >= (int32_t) (2 * tp->t_maxseg)) { + /* + * Update only if the resulting scaled value of + * the window changed, or if there is a change in + * the sequence since the last ack. This avoids + * what appears as dupe ACKS (see rdar://5640997) + * + * If streaming is detected avoid sending too many + * window updates. We will depend on the delack + * timer to send a window update when needed. + */ + if (!(tp->t_flags & TF_STRETCHACK) && + (tp->last_ack_sent != tp->rcv_nxt || + ((oldwin + adv) >> tp->rcv_scale) > + (oldwin >> tp->rcv_scale))) { + goto send; + } + + } + if (4 * adv >= (int32_t) so->so_rcv.sb_hiwat) goto send; + + /* + * Make sure that the delayed ack timer is set if + * we delayed sending a window update because of + * streaming detection. + */ + if ((tp->t_flags & TF_STRETCHACK) && + !(tp->t_flags & TF_DELACK)) { + tp->t_flags |= TF_DELACK; + tp->t_timer[TCPT_DELACK] = + OFFSET_FROM_START(tp, tcp_delack); + } } /* - * Send if we owe peer an ACK. + * Send if we owe the peer an ACK, RST, SYN, or urgent data. ACKNOW + * is also a catch-all for the retransmit timer timeout case. */ if (tp->t_flags & TF_ACKNOW) goto send; @@ -324,15 +1372,30 @@ again: goto send; if (SEQ_GT(tp->snd_up, tp->snd_una)) goto send; +#if MPTCP + if (mptcp_acknow) + goto send; +#endif /* MPTCP */ /* * If our state indicates that FIN should be sent - * and we have not yet done so, or we're retransmitting the FIN, - * then we need to send. + * and we have not yet done so, then we need to send. */ - if (flags & TH_FIN && - ((tp->t_flags & TF_SENTFIN) == 0 || tp->snd_nxt == tp->snd_una)) + if ((flags & TH_FIN) && + (!(tp->t_flags & TF_SENTFIN) || tp->snd_nxt == tp->snd_una)) goto send; - + /* + * In SACK, it is possible for tcp_output to fail to send a segment + * after the retransmission timer has been turned off. Make sure + * that the retransmission timer is set. + */ + if (SACK_ENABLED(tp) && (tp->t_state >= TCPS_ESTABLISHED) && + SEQ_GT(tp->snd_max, tp->snd_una) && + tp->t_timer[TCPT_REXMT] == 0 && + tp->t_timer[TCPT_PERSIST] == 0) { + tp->t_timer[TCPT_REXMT] = OFFSET_FROM_START(tp, + tp->t_rxtcur); + goto just_return; + } /* * TCP window updates are not reliable, rather a polling protocol * using ``persist'' packets is used to insure receipt of window @@ -357,32 +1420,63 @@ again: */ if (so->so_snd.sb_cc && tp->t_timer[TCPT_REXMT] == 0 && tp->t_timer[TCPT_PERSIST] == 0) { - tp->t_rxtshift = 0; + TCP_RESET_REXMT_STATE(tp); tcp_setpersist(tp); } - +just_return: /* - * No reason to send a segment, just return. + * If there is no reason to send a segment, just return. + * but if there is some packets left in the packet list, send them now. */ + while (inp->inp_sndinprog_cnt == 0 && + tp->t_pktlist_head != NULL) { + packetlist = tp->t_pktlist_head; + packchain_listadd = tp->t_lastchain; + packchain_sent++; + TCP_PKTLIST_CLEAR(tp); + + error = tcp_ip_output(so, tp, packetlist, + packchain_listadd, + tp_inp_options, (so_options & SO_DONTROUTE), + (sack_rxmit || (sack_bytes_rxmt != 0)), isipv6); + } + /* tcp was closed while we were in ip; resume close */ + if (inp->inp_sndinprog_cnt == 0 && + (tp->t_flags & TF_CLOSING)) { + tp->t_flags &= ~TF_CLOSING; + (void) tcp_close(tp); + } else { + tcp_check_timer_state(tp); + } KERNEL_DEBUG(DBG_FNC_TCP_OUTPUT | DBG_FUNC_END, 0,0,0,0,0); return (0); send: + /* + * Set TF_MAXSEGSNT flag if the segment size is greater than + * the max segment size. + */ + if (len > 0) { + if (len >= tp->t_maxseg) + tp->t_flags |= TF_MAXSEGSNT; + else + tp->t_flags &= ~TF_MAXSEGSNT; + } /* * Before ESTABLISHED, force sending of initial options * unless TCP set not to do any options. * NOTE: we assume that the IP/TCP header plus TCP options * always fit in a single mbuf, leaving room for a maximum * link header, i.e. - * max_linkhdr + sizeof (struct tcpiphdr) + optlen <= MHLEN + * max_linkhdr + sizeof (struct tcpiphdr) + optlen <= MCLBYTES */ optlen = 0; #if INET6 if (isipv6) - hdrlen = sizeof (struct tcpip6hdr); + hdrlen = sizeof (struct ip6_hdr) + sizeof (struct tcphdr); else #endif - hdrlen = sizeof (struct tcpiphdr); + hdrlen = sizeof (struct tcpiphdr); if (flags & TH_SYN) { tp->snd_nxt = tp->iss; if ((tp->t_flags & TF_NOOPT) == 0) { @@ -390,24 +1484,29 @@ send: opt[0] = TCPOPT_MAXSEG; opt[1] = TCPOLEN_MAXSEG; - mss = htons((u_short) tcp_mssopt(tp, isipv6)); + mss = htons((u_short) tcp_mssopt(tp)); (void)memcpy(opt + 2, &mss, sizeof(mss)); optlen = TCPOLEN_MAXSEG; if ((tp->t_flags & TF_REQ_SCALE) && ((flags & TH_ACK) == 0 || (tp->t_flags & TF_RCVD_SCALE))) { - *((u_int32_t *)(opt + optlen)) = htonl( + *((u_int32_t *)(void *)(opt + optlen)) = htonl( TCPOPT_NOP << 24 | TCPOPT_WINDOW << 16 | TCPOLEN_WINDOW << 8 | tp->request_r_scale); optlen += 4; } +#if MPTCP + if (mptcp_enable && (so->so_flags & SOF_MP_SUBFLOW)) { + optlen = mptcp_setup_syn_opts(so, opt, optlen); + } +#endif /* MPTCP */ } - } + } - /* + /* * Send a timestamp and echo-reply if this is a SYN and our side * wants to use timestamps (TF_REQ_TSTMP is set) or both our side * and our peer have sent timestamps in our SYN's. @@ -416,7 +1515,7 @@ send: (flags & TH_RST) == 0 && ((flags & TH_ACK) == 0 || (tp->t_flags & TF_RCVD_TSTMP))) { - u_int32_t *lp = (u_int32_t *)(opt + optlen); + u_int32_t *lp = (u_int32_t *)(void *)(opt + optlen); /* Form timestamp option as shown in appendix A of RFC 1323. */ *lp++ = htonl(TCPOPT_TSTAMP_HDR); @@ -425,95 +1524,274 @@ send: optlen += TCPOLEN_TSTAMP_APPA; } - /* - * Send `CC-family' options if our side wants to use them (TF_REQ_CC), - * options are allowed (!TF_NOOPT) and it's not a RST. - */ - if ((tp->t_flags & (TF_REQ_CC|TF_NOOPT)) == TF_REQ_CC && - (flags & TH_RST) == 0) { - switch (flags & (TH_SYN|TH_ACK)) { + /* Note the timestamp for receive buffer autosizing */ + if (tp->rfbuf_ts == 0 && (so->so_rcv.sb_flags & SB_AUTOSIZE)) + tp->rfbuf_ts = tcp_now; + + if (SACK_ENABLED(tp) && ((tp->t_flags & TF_NOOPT) == 0)) { /* - * This is a normal ACK, send CC if we received CC before - * from our peer. + * Tack on the SACK permitted option *last*. + * And do padding of options after tacking this on. + * This is because of MSS, TS, WinScale and Signatures are + * all present, we have just 2 bytes left for the SACK + * permitted option, which is just enough. */ - case TH_ACK: - if (!(tp->t_flags & TF_RCVD_CC)) - break; - /*FALLTHROUGH*/ - /* - * We can only get here in T/TCP's SYN_SENT* state, when - * we're a sending a non-SYN segment without waiting for - * the ACK of our SYN. A check above assures that we only - * do this if our peer understands T/TCP. + * If this is the first SYN of connection (not a SYN + * ACK), include SACK permitted option. If this is a + * SYN ACK, include SACK permitted option if peer has + * already done so. This is only for active connect, + * since the syncache takes care of the passive connect. */ - case 0: - opt[optlen++] = TCPOPT_NOP; - opt[optlen++] = TCPOPT_NOP; - opt[optlen++] = TCPOPT_CC; - opt[optlen++] = TCPOLEN_CC; - *(u_int32_t *)&opt[optlen] = htonl(tp->cc_send); - - optlen += 4; - break; + if ((flags & TH_SYN) && + (!(flags & TH_ACK) || (tp->t_flags & TF_SACK_PERMIT))) { + u_char *bp; + bp = (u_char *)opt + optlen; + *bp++ = TCPOPT_SACK_PERMITTED; + *bp++ = TCPOLEN_SACK_PERMITTED; + optlen += TCPOLEN_SACK_PERMITTED; + } + } +#if MPTCP + if (so->so_flags & SOF_MP_SUBFLOW) { /* - * This is our initial SYN, check whether we have to use - * CC or CC.new. + * Its important to piggyback acks with data as ack only packets + * may get lost and data packets that don't send Data ACKs + * still advance the subflow level ACK and therefore make it + * hard for the remote end to recover in low cwnd situations. */ - case TH_SYN: - opt[optlen++] = TCPOPT_NOP; - opt[optlen++] = TCPOPT_NOP; - opt[optlen++] = tp->t_flags & TF_SENDCCNEW ? - TCPOPT_CCNEW : TCPOPT_CC; - opt[optlen++] = TCPOLEN_CC; - *(u_int32_t *)&opt[optlen] = htonl(tp->cc_send); - optlen += 4; - break; + if (len != 0) { + tp->t_mpflags |= (TMPF_SEND_DSN | + TMPF_MPTCP_ACKNOW); + } else { + tp->t_mpflags |= TMPF_MPTCP_ACKNOW; + } + optlen = mptcp_setup_opts(tp, off, &opt[0], optlen, flags, + len, &mptcp_acknow); + tp->t_mpflags &= ~TMPF_SEND_DSN; + } +#endif /* MPTCP */ + + if (tfo_enabled(tp) && !(tp->t_flags & TF_NOOPT) && + (flags & (TH_SYN | TH_ACK)) == TH_SYN) + optlen += tcp_tfo_write_cookie(tp, optlen, len, opt); + if (tfo_enabled(tp) && + (flags & (TH_SYN | TH_ACK)) == (TH_SYN | TH_ACK) && + (tp->t_tfo_flags & TFO_F_OFFER_COOKIE)) + optlen += tcp_tfo_write_cookie_rep(tp, optlen, opt); + + if (SACK_ENABLED(tp) && ((tp->t_flags & TF_NOOPT) == 0)) { /* - * This is a SYN,ACK; send CC and CC.echo if we received - * CC from our peer. + * Send SACKs if necessary. This should be the last + * option processed. Only as many SACKs are sent as + * are permitted by the maximum options size. + * + * In general, SACK blocks consume 8*n+2 bytes. + * So a full size SACK blocks option is 34 bytes + * (to generate 4 SACK blocks). At a minimum, + * we need 10 bytes (to generate 1 SACK block). + * If TCP Timestamps (12 bytes) and TCP Signatures + * (18 bytes) are both present, we'll just have + * 10 bytes for SACK options 40 - (12 + 18). */ - case (TH_SYN|TH_ACK): - if (tp->t_flags & TF_RCVD_CC) { - opt[optlen++] = TCPOPT_NOP; - opt[optlen++] = TCPOPT_NOP; - opt[optlen++] = TCPOPT_CC; - opt[optlen++] = TCPOLEN_CC; - *(u_int32_t *)&opt[optlen] = - htonl(tp->cc_send); - optlen += 4; - opt[optlen++] = TCPOPT_NOP; - opt[optlen++] = TCPOPT_NOP; - opt[optlen++] = TCPOPT_CCECHO; - opt[optlen++] = TCPOLEN_CC; - *(u_int32_t *)&opt[optlen] = - htonl(tp->cc_recv); - optlen += 4; + if (TCPS_HAVEESTABLISHED(tp->t_state) && + (tp->t_flags & TF_SACK_PERMIT) && + (tp->rcv_numsacks > 0 || TCP_SEND_DSACK_OPT(tp)) && + MAX_TCPOPTLEN - optlen - 2 >= TCPOLEN_SACK) { + int nsack, padlen; + u_char *bp = (u_char *)opt + optlen; + u_int32_t *lp; + + nsack = (MAX_TCPOPTLEN - optlen - 2) / TCPOLEN_SACK; + nsack = min(nsack, (tp->rcv_numsacks + + (TCP_SEND_DSACK_OPT(tp) ? 1 : 0))); + sackoptlen = (2 + nsack * TCPOLEN_SACK); + + /* + * First we need to pad options so that the + * SACK blocks can start at a 4-byte boundary + * (sack option and length are at a 2 byte offset). + */ + padlen = (MAX_TCPOPTLEN - optlen - sackoptlen) % 4; + optlen += padlen; + while (padlen-- > 0) + *bp++ = TCPOPT_NOP; + + tcpstat.tcps_sack_send_blocks++; + *bp++ = TCPOPT_SACK; + *bp++ = sackoptlen; + lp = (u_int32_t *)(void *)bp; + + /* + * First block of SACK option should represent + * DSACK. Prefer to send SACK information if there + * is space for only one SACK block. This will + * allow for faster recovery. + */ + if (TCP_SEND_DSACK_OPT(tp) && nsack > 0 && + (tp->rcv_numsacks == 0 || nsack > 1)) { + *lp++ = htonl(tp->t_dsack_lseq); + *lp++ = htonl(tp->t_dsack_rseq); + tcpstat.tcps_dsack_sent++; + tp->t_dsack_sent++; + nsack--; } - break; + VERIFY(nsack == 0 || tp->rcv_numsacks >= nsack); + for (i = 0; i < nsack; i++) { + struct sackblk sack = tp->sackblks[i]; + *lp++ = htonl(sack.start); + *lp++ = htonl(sack.end); + } + optlen += sackoptlen; } - } + } + + /* Pad TCP options to a 4 byte boundary */ + if (optlen < MAX_TCPOPTLEN && (optlen % sizeof(u_int32_t))) { + int pad = sizeof(u_int32_t) - (optlen % sizeof(u_int32_t)); + u_char *bp = (u_char *)opt + optlen; + + optlen += pad; + while (pad) { + *bp++ = TCPOPT_EOL; + pad--; + } + } + + /* + * RFC 3168 states that: + * - If you ever sent an ECN-setup SYN/SYN-ACK you must be prepared + * to handle the TCP ECE flag, even if you also later send a + * non-ECN-setup SYN/SYN-ACK. + * - If you ever send a non-ECN-setup SYN/SYN-ACK, you must not set + * the ip ECT flag. + * + * It is not clear how the ECE flag would ever be set if you never + * set the IP ECT flag on outbound packets. All the same, we use + * the TE_SETUPSENT to indicate that we have committed to handling + * the TCP ECE flag correctly. We use the TE_SENDIPECT to indicate + * whether or not we should set the IP ECT flag on outbound packet + * + * For a SYN-ACK, send an ECN setup SYN-ACK + */ + if ((flags & (TH_SYN | TH_ACK)) == (TH_SYN | TH_ACK) && + (tp->ecn_flags & TE_ENABLE_ECN)) { + if (tp->ecn_flags & TE_SETUPRECEIVED) { + if (tcp_send_ecn_flags_on_syn(tp, so)) { + /* + * Setting TH_ECE makes this an ECN-setup + * SYN-ACK + */ + flags |= TH_ECE; + + /* + * Record that we sent the ECN-setup and + * default to setting IP ECT. + */ + tp->ecn_flags |= (TE_SETUPSENT|TE_SENDIPECT); + tcpstat.tcps_ecn_server_setup++; + tcpstat.tcps_ecn_server_success++; + } else { + /* + * We sent an ECN-setup SYN-ACK but it was + * dropped. Fallback to non-ECN-setup + * SYN-ACK and clear flag to indicate that + * we should not send data with IP ECT set + * + * Pretend we didn't receive an + * ECN-setup SYN. + * + * We already incremented the counter + * assuming that the ECN setup will + * succeed. Decrementing here + * tcps_ecn_server_success to correct it. + */ + if (tp->ecn_flags & TE_SETUPSENT) { + tcpstat.tcps_ecn_lost_synack++; + tcpstat.tcps_ecn_server_success--; + tp->ecn_flags |= TE_LOST_SYNACK; + } + + tp->ecn_flags &= + ~(TE_SETUPRECEIVED | TE_SENDIPECT | + TE_SENDCWR); + } + } + } else if ((flags & (TH_SYN | TH_ACK)) == TH_SYN && + (tp->ecn_flags & TE_ENABLE_ECN)) { + if (tcp_send_ecn_flags_on_syn(tp, so)) { + /* + * Setting TH_ECE and TH_CWR makes this an + * ECN-setup SYN + */ + flags |= (TH_ECE | TH_CWR); + tcpstat.tcps_ecn_client_setup++; + tp->ecn_flags |= TE_CLIENT_SETUP; + + /* + * Record that we sent the ECN-setup and default to + * setting IP ECT. + */ + tp->ecn_flags |= (TE_SETUPSENT | TE_SENDIPECT); + } else { + /* + * We sent an ECN-setup SYN but it was dropped. + * Fall back to non-ECN and clear flag indicating + * we should send data with IP ECT set. + */ + if (tp->ecn_flags & TE_SETUPSENT) { + tcpstat.tcps_ecn_lost_syn++; + tp->ecn_flags |= TE_LOST_SYN; + } + tp->ecn_flags &= ~TE_SENDIPECT; + } + } + + /* + * Check if we should set the TCP CWR flag. + * CWR flag is sent when we reduced the congestion window because + * we received a TCP ECE or we performed a fast retransmit. We + * never set the CWR flag on retransmitted packets. We only set + * the CWR flag on data packets. Pure acks don't have this set. + */ + if ((tp->ecn_flags & TE_SENDCWR) != 0 && len != 0 && + !SEQ_LT(tp->snd_nxt, tp->snd_max) && !sack_rxmit) { + flags |= TH_CWR; + tp->ecn_flags &= ~TE_SENDCWR; + } + + /* + * Check if we should set the TCP ECE flag. + */ + if ((tp->ecn_flags & TE_SENDECE) != 0 && len == 0) { + flags |= TH_ECE; + tcpstat.tcps_ecn_sent_ece++; + } + + + hdrlen += optlen; + + /* Reset DSACK sequence numbers */ + tp->t_dsack_lseq = 0; + tp->t_dsack_rseq = 0; - hdrlen += optlen; #if INET6 if (isipv6) - ipoptlen = ip6_optlen(tp->t_inpcb); + ipoptlen = ip6_optlen(inp); else #endif - if (tp->t_inpcb->inp_options) { - ipoptlen = tp->t_inpcb->inp_options->m_len - + { + if (tp_inp_options) { + ipoptlen = tp_inp_options->m_len - offsetof(struct ipoption, ipopt_list); - } else { - ipoptlen = 0; + } else { + ipoptlen = 0; + } } #if IPSEC -#if INET6 - ipoptlen += ipsec_hdrsiz_tcp(tp, isipv6); -#else - ipoptlen += ipsec_hdrsiz_tcp(tp, 0); -#endif + ipoptlen += ipsec_optlen; #endif /* @@ -521,85 +1799,214 @@ send: * bump the packet length beyond the t_maxopd length. * Clear the FIN bit because we cut off the tail of * the segment. + * + * When doing TSO limit a burst to TCP_MAXWIN minus the + * IP, TCP and Options length to keep ip->ip_len from + * overflowing. Prevent the last segment from being + * fractional thus making them all equal sized and set + * the flag to continue sending. TSO is disabled when + * IP options or IPSEC are present. */ if (len + optlen + ipoptlen > tp->t_maxopd) { /* - * If there is still more to send, don't close the connection. + * If there is still more to send, + * don't close the connection. */ flags &= ~TH_FIN; - len = tp->t_maxopd - optlen - ipoptlen; - sendalot = 1; + if (tso) { + int32_t tso_maxlen; + + tso_maxlen = tp->tso_max_segment_size ? + tp->tso_max_segment_size : TCP_MAXWIN; + + if (len > tso_maxlen - hdrlen - optlen) { + len = tso_maxlen - hdrlen - optlen; + len = len - (len % (tp->t_maxopd - optlen)); + sendalot = 1; + } else if (tp->t_flags & TF_NEEDFIN) { + sendalot = 1; + } + } else { + len = tp->t_maxopd - optlen - ipoptlen; + sendalot = 1; + } } -/*#ifdef DIAGNOSTIC*/ - if (max_linkhdr + hdrlen > MHLEN) + if (max_linkhdr + hdrlen > MCLBYTES) panic("tcphdr too big"); -/*#endif*/ + /* Check if there is enough data in the send socket + * buffer to start measuring bandwidth + */ + if ((tp->t_flagsext & TF_MEASURESNDBW) != 0 && + (tp->t_bwmeas != NULL) && + (tp->t_flagsext & TF_BWMEAS_INPROGRESS) == 0) { + tp->t_bwmeas->bw_size = min(min( + (so->so_snd.sb_cc - (tp->snd_max - tp->snd_una)), + tp->snd_cwnd), tp->snd_wnd); + if (tp->t_bwmeas->bw_minsize > 0 && + tp->t_bwmeas->bw_size < tp->t_bwmeas->bw_minsize) + tp->t_bwmeas->bw_size = 0; + if (tp->t_bwmeas->bw_maxsize > 0) + tp->t_bwmeas->bw_size = min(tp->t_bwmeas->bw_size, + tp->t_bwmeas->bw_maxsize); + if (tp->t_bwmeas->bw_size > 0) { + tp->t_flagsext |= TF_BWMEAS_INPROGRESS; + tp->t_bwmeas->bw_start = tp->snd_max; + tp->t_bwmeas->bw_ts = tcp_now; + } + } + + VERIFY(inp->inp_flowhash != 0); /* * Grab a header mbuf, attaching a copy of data to * be transmitted, and initialize the header from * the template for sends on this connection. */ if (len) { - if (tp->t_force && len == 1) + tp->t_pmtud_lastseg_size = len + optlen + ipoptlen; + if ((tp->t_flagsext & TF_FORCE) && len == 1) tcpstat.tcps_sndprobe++; - else if (SEQ_LT(tp->snd_nxt, tp->snd_max)) { + else if (SEQ_LT(tp->snd_nxt, tp->snd_max) || sack_rxmit) { tcpstat.tcps_sndrexmitpack++; tcpstat.tcps_sndrexmitbyte += len; + if (nstat_collect) { + nstat_route_tx(inp->inp_route.ro_rt, 1, + len, NSTAT_TX_FLAG_RETRANSMIT); + INP_ADD_STAT(inp, cell, wifi, wired, + txpackets, 1); + INP_ADD_STAT(inp, cell, wifi, wired, + txbytes, len); + tp->t_stat.txretransmitbytes += len; + tp->t_stat.rxmitpkts++; + } } else { tcpstat.tcps_sndpack++; tcpstat.tcps_sndbyte += len; + + if (nstat_collect) { + INP_ADD_STAT(inp, cell, wifi, wired, + txpackets, 1); + INP_ADD_STAT(inp, cell, wifi, wired, + txbytes, len); + } + inp_decr_sndbytes_unsent(so, len); } -#ifdef notyet - if ((m = m_copypack(so->so_snd.sb_mb, off, - (int)len, max_linkhdr + hdrlen)) == 0) { - error = ENOBUFS; - goto out; + inp_set_activity_bitmap(inp); +#if MPTCP + if (tp->t_mpflags & TMPF_MPTCP_TRUE) { + tcpstat.tcps_mp_sndpacks++; + tcpstat.tcps_mp_sndbytes += len; } +#endif /* MPTCP */ /* - * m_copypack left space for our hdr; use it. + * try to use the new interface that allocates all + * the necessary mbuf hdrs under 1 mbuf lock and + * avoids rescanning the socket mbuf list if + * certain conditions are met. This routine can't + * be used in the following cases... + * 1) the protocol headers exceed the capacity of + * of a single mbuf header's data area (no cluster attached) + * 2) the length of the data being transmitted plus + * the protocol headers fits into a single mbuf header's + * data area (no cluster attached) */ - m->m_len += hdrlen; - m->m_data -= hdrlen; -#else - MGETHDR(m, M_DONTWAIT, MT_HEADER); - if (m == NULL) { - error = ENOBUFS; - goto out; - } -#if INET6 + m = NULL; + + /* minimum length we are going to allocate */ + allocated_len = MHLEN; if (MHLEN < hdrlen + max_linkhdr) { + MGETHDR(m, M_DONTWAIT, MT_HEADER); + if (m == NULL) { + error = ENOBUFS; + goto out; + } MCLGET(m, M_DONTWAIT); if ((m->m_flags & M_EXT) == 0) { m_freem(m); error = ENOBUFS; goto out; } + m->m_data += max_linkhdr; + m->m_len = hdrlen; + allocated_len = MCLBYTES; } -#endif - m->m_data += max_linkhdr; - m->m_len = hdrlen; - if (len <= MHLEN - hdrlen - max_linkhdr) { + if (len <= allocated_len - hdrlen - max_linkhdr) { + if (m == NULL) { + VERIFY(allocated_len <= MHLEN); + MGETHDR(m, M_DONTWAIT, MT_HEADER); + if (m == NULL) { + error = ENOBUFS; + goto out; + } + m->m_data += max_linkhdr; + m->m_len = hdrlen; + } + /* makes sure we still have data left to be sent at this point */ + if (so->so_snd.sb_mb == NULL || off < 0) { + if (m != NULL) m_freem(m); + error = 0; /* should we return an error? */ + goto out; + } m_copydata(so->so_snd.sb_mb, off, (int) len, mtod(m, caddr_t) + hdrlen); m->m_len += len; } else { - m->m_next = m_copy(so->so_snd.sb_mb, off, (int) len); - if (m->m_next == 0) { - (void) m_free(m); - error = ENOBUFS; - goto out; + uint32_t copymode; + /* + * Retain packet header metadata at the socket + * buffer if this is is an MPTCP subflow, + * otherwise move it. + */ + copymode = M_COPYM_MOVE_HDR; +#if MPTCP + if (so->so_flags & SOF_MP_SUBFLOW) { + copymode = M_COPYM_NOOP_HDR; + } +#endif /* MPTCP */ + if (m != NULL) { + m->m_next = m_copym_mode(so->so_snd.sb_mb, + off, (int)len, M_DONTWAIT, copymode); + if (m->m_next == NULL) { + (void) m_free(m); + error = ENOBUFS; + goto out; + } + } else { + /* + * make sure we still have data left + * to be sent at this point + */ + if (so->so_snd.sb_mb == NULL) { + error = 0; /* should we return an error? */ + goto out; + } + + /* + * m_copym_with_hdrs will always return the + * last mbuf pointer and the offset into it that + * it acted on to fullfill the current request, + * whether a valid 'hint' was passed in or not. + */ + if ((m = m_copym_with_hdrs(so->so_snd.sb_mb, + off, len, M_DONTWAIT, NULL, NULL, + copymode)) == NULL) { + error = ENOBUFS; + goto out; + } + m->m_data += max_linkhdr; + m->m_len = hdrlen; } } -#endif /* * If we're sending everything we've got, set PUSH. * (This will keep happy those implementations which only * give data to the user when a buffer fills or * a PUSH comes in.) + * + * On SYN-segments we should not add the PUSH-flag. */ - if (off + len == so->so_snd.sb_cc) + if (off + len == so->so_snd.sb_cc && !(flags & TH_SYN)) flags |= TH_PUSH; } else { if (tp->t_flags & TF_ACKNOW) @@ -611,48 +2018,65 @@ send: else tcpstat.tcps_sndwinup++; - MGETHDR(m, M_DONTWAIT, MT_HEADER); + MGETHDR(m, M_DONTWAIT, MT_HEADER); /* MAC-OK */ if (m == NULL) { error = ENOBUFS; goto out; } -#if INET6 - if (isipv6) { - MH_ALIGN(m, hdrlen); - } else -#endif + if (MHLEN < (hdrlen + max_linkhdr)) { + MCLGET(m, M_DONTWAIT); + if ((m->m_flags & M_EXT) == 0) { + m_freem(m); + error = ENOBUFS; + goto out; + } + } m->m_data += max_linkhdr; m->m_len = hdrlen; } - m->m_pkthdr.rcvif = (struct ifnet *)0; - if (tp->t_template == 0) - panic("tcp_output"); + m->m_pkthdr.rcvif = 0; +#if CONFIG_MACF_NET + mac_mbuf_label_associate_inpcb(inp, m); +#endif #if INET6 if (isipv6) { ip6 = mtod(m, struct ip6_hdr *); - th = (struct tcphdr *)(ip6 + 1); - bcopy((caddr_t)&tp->t_template->tt_i6, (caddr_t)ip6, - sizeof(struct ip6_hdr)); - bcopy((caddr_t)&tp->t_template->tt_t, (caddr_t)th, - sizeof(struct tcphdr)); - } else { + th = (struct tcphdr *)(void *)(ip6 + 1); + tcp_fillheaders(tp, ip6, th); + if ((tp->ecn_flags & TE_SENDIPECT) != 0 && len && + !SEQ_LT(tp->snd_nxt, tp->snd_max) && !sack_rxmit) { + ip6->ip6_flow |= htonl(IPTOS_ECN_ECT0 << 20); + } + svc_flags |= PKT_SCF_IPV6; +#if PF_ECN + m_pftag(m)->pftag_hdr = (void *)ip6; + m_pftag(m)->pftag_flags |= PF_TAG_HDR_INET6; +#endif /* PF_ECN */ + } else #endif /* INET6 */ - ip = mtod(m, struct ip *); - ipov = (struct ipovly *)ip; - th = (struct tcphdr *)(ip + 1); - bcopy((caddr_t)&tp->t_template->tt_i, (caddr_t)ip, sizeof(struct ip)); - bcopy((caddr_t)&tp->t_template->tt_t, (caddr_t)th, - sizeof(struct tcphdr)); -#if INET6 + { + ip = mtod(m, struct ip *); + ipov = (struct ipovly *)ip; + th = (struct tcphdr *)(void *)(ip + 1); + /* this picks up the pseudo header (w/o the length) */ + tcp_fillheaders(tp, ip, th); + if ((tp->ecn_flags & TE_SENDIPECT) != 0 && len && + !SEQ_LT(tp->snd_nxt, tp->snd_max) && + !sack_rxmit && !(flags & TH_SYN)) { + ip->ip_tos |= IPTOS_ECN_ECT0; + } +#if PF_ECN + m_pftag(m)->pftag_hdr = (void *)ip; + m_pftag(m)->pftag_flags |= PF_TAG_HDR_INET; +#endif /* PF_ECN */ } -#endif /* INET6 */ /* * Fill in fields, remembering maximum advertised * window for use in delaying messages about window sizes. * If resending a FIN, be sure not to use a new sequence number. */ - if (flags & TH_FIN && tp->t_flags & TF_SENTFIN && + if ((flags & TH_FIN) && (tp->t_flags & TF_SENTFIN) && tp->snd_nxt == tp->snd_max) tp->snd_nxt--; /* @@ -667,32 +2091,68 @@ send: * right edge of the window, so use snd_nxt in that * case, since we know we aren't doing a retransmission. * (retransmit and persist are mutually exclusive...) + * + * Note the state of this retransmit segment to detect spurious + * retransmissions. */ - if (len || (flags & (TH_SYN|TH_FIN)) || tp->t_timer[TCPT_PERSIST]) - th->th_seq = htonl(tp->snd_nxt); - else - th->th_seq = htonl(tp->snd_max); + if (sack_rxmit == 0) { + if (len || (flags & (TH_SYN|TH_FIN)) || + tp->t_timer[TCPT_PERSIST]) { + th->th_seq = htonl(tp->snd_nxt); + if (len > 0) { + m->m_pkthdr.tx_start_seq = tp->snd_nxt; + m->m_pkthdr.pkt_flags |= PKTF_START_SEQ; + } + if (SEQ_LT(tp->snd_nxt, tp->snd_max)) { + if (SACK_ENABLED(tp) && len > 1) { + tcp_rxtseg_insert(tp, tp->snd_nxt, + (tp->snd_nxt + len - 1)); + } + if (len > 0) + m->m_pkthdr.pkt_flags |= + PKTF_TCP_REXMT; + } + } else { + th->th_seq = htonl(tp->snd_max); + } + } else { + th->th_seq = htonl(p->rxmit); + if (len > 0) { + m->m_pkthdr.pkt_flags |= + (PKTF_TCP_REXMT | PKTF_START_SEQ); + m->m_pkthdr.tx_start_seq = p->rxmit; + } + tcp_rxtseg_insert(tp, p->rxmit, (p->rxmit + len - 1)); + p->rxmit += len; + tp->sackhint.sack_bytes_rexmit += len; + } th->th_ack = htonl(tp->rcv_nxt); + tp->last_ack_sent = tp->rcv_nxt; if (optlen) { bcopy(opt, th + 1, optlen); th->th_off = (sizeof (struct tcphdr) + optlen) >> 2; } th->th_flags = flags; + th->th_win = htons((u_short) (recwin>>tp->rcv_scale)); + if (recwin > 0 && SEQ_LT(tp->rcv_adv, tp->rcv_nxt + recwin)) + tp->rcv_adv = tp->rcv_nxt + recwin; + /* - * Calculate receive window. Don't shrink window, - * but avoid silly window syndrome. + * Adjust the RXWIN0SENT flag - indicate that we have advertised + * a 0 window. This may cause the remote transmitter to stall. This + * flag tells soreceive() to disable delayed acknowledgements when + * draining the buffer. This can occur if the receiver is attempting + * to read more data then can be buffered prior to transmitting on + * the connection. */ - if (win < (long)(so->so_rcv.sb_hiwat / 4) && win < (long)tp->t_maxseg) - win = 0; - if (win < (long)(tp->rcv_adv - tp->rcv_nxt)) - win = (long)(tp->rcv_adv - tp->rcv_nxt); - if (win > (long)TCP_MAXWIN << tp->rcv_scale) - win = (long)TCP_MAXWIN << tp->rcv_scale; - th->th_win = htons((u_short) (win>>tp->rcv_scale)); + if (th->th_win == 0) + tp->t_flags |= TF_RXWIN0SENT; + else + tp->t_flags &= ~TF_RXWIN0SENT; if (SEQ_GT(tp->snd_up, tp->snd_nxt)) { th->th_urp = htons((u_short)(tp->snd_up - tp->snd_nxt)); th->th_flags |= TH_URG; - } else + } else { /* * If no urgent pointer to send, then we pull * the urgent pointer to the left edge of the send window @@ -700,42 +2160,69 @@ send: * number wraparound. */ tp->snd_up = tp->snd_una; /* drag it along */ + } /* * Put TCP length in extended header, and then * checksum extended header and data. */ - m->m_pkthdr.len = hdrlen + len; + m->m_pkthdr.len = hdrlen + len; /* in6_cksum() need this */ + + /* + * If this is potentially the last packet on the stream, then mark + * it in order to enable some optimizations in the underlying + * layers + */ + if (tp->t_state != TCPS_ESTABLISHED && + (tp->t_state == TCPS_CLOSING || tp->t_state == TCPS_TIME_WAIT + || tp->t_state == TCPS_LAST_ACK || (th->th_flags & TH_RST))) + m->m_pkthdr.pkt_flags |= PKTF_LAST_PKT; + #if INET6 if (isipv6) { -#if 0 /* ip6_plen will be filled in ip6_output. */ - ip6->ip6_plen = htons((u_short)(sizeof(struct tcphdr) + - optlen + len)); -#endif - - th->th_sum = in6_cksum(m, IPPROTO_TCP, sizeof(struct ip6_hdr), - sizeof(struct tcphdr) + optlen + len); - } else + /* + * ip6_plen is not need to be filled now, and will be filled + * in ip6_output. + */ + m->m_pkthdr.csum_flags = CSUM_TCPIPV6; + m->m_pkthdr.csum_data = offsetof(struct tcphdr, th_sum); + if (len + optlen) + th->th_sum = in_addword(th->th_sum, + htons((u_short)(optlen + len))); + } + else #endif /* INET6 */ { - - if (len + optlen) - ipov->ih_len = htons((u_short)(sizeof (struct tcphdr) + - optlen + len)); - m->m_pkthdr.csum_flags = CSUM_TCP; - m->m_pkthdr.csum_data = offsetof(struct tcphdr, th_sum); - if (len + optlen) { - th->th_sum = in_addword(th->th_sum, - htons((u_short)(optlen + len))); - } - + m->m_pkthdr.csum_flags = CSUM_TCP; + m->m_pkthdr.csum_data = offsetof(struct tcphdr, th_sum); + if (len + optlen) + th->th_sum = in_addword(th->th_sum, + htons((u_short)(optlen + len))); + } + + /* + * Enable TSO and specify the size of the segments. + * The TCP pseudo header checksum is always provided. + */ + if (tso) { +#if INET6 + if (isipv6) + m->m_pkthdr.csum_flags |= CSUM_TSO_IPV6; + else +#endif /* INET6 */ + m->m_pkthdr.csum_flags |= CSUM_TSO_IPV4; + + m->m_pkthdr.tso_segsz = tp->t_maxopd - optlen; + } else { + m->m_pkthdr.tso_segsz = 0; } /* * In transmit state, time the transmission and arrange for * the retransmit. In persist state, just set snd_max. */ - if (tp->t_force == 0 || tp->t_timer[TCPT_PERSIST] == 0) { + if (!(tp->t_flagsext & TF_FORCE) + || tp->t_timer[TCPT_PERSIST] == 0) { tcp_seq startseq = tp->snd_nxt; /* @@ -744,66 +2231,117 @@ send: if (flags & (TH_SYN|TH_FIN)) { if (flags & TH_SYN) tp->snd_nxt++; - if (flags & TH_FIN) { + if ((flags & TH_FIN) && + !(tp->t_flags & TF_SENTFIN)) { tp->snd_nxt++; tp->t_flags |= TF_SENTFIN; } } - tp->snd_nxt += len; + if (sack_rxmit) + goto timer; + if (sack_rescue_rxt == TRUE) { + tp->snd_nxt = old_snd_nxt; + sack_rescue_rxt = FALSE; + tcpstat.tcps_pto_in_recovery++; + } else { + tp->snd_nxt += len; + } if (SEQ_GT(tp->snd_nxt, tp->snd_max)) { tp->snd_max = tp->snd_nxt; + tp->t_sndtime = tcp_now; /* * Time this transmission if not a retransmission and * not currently timing anything. */ - if (tp->t_rtt == 0) { - tp->t_rtt = 1; + if (tp->t_rtttime == 0) { + tp->t_rtttime = tcp_now; tp->t_rtseq = startseq; tcpstat.tcps_segstimed++; + + /* update variables related to pipe ack */ + tp->t_pipeack_lastuna = tp->snd_una; } } /* * Set retransmit timer if not currently set, * and not doing an ack or a keep-alive probe. - * Initial value for retransmit timer is smoothed - * round-trip time + 2 * round-trip time variance. - * Initialize shift counter which is used for backoff - * of retransmit time. */ +timer: if (tp->t_timer[TCPT_REXMT] == 0 && - tp->snd_nxt != tp->snd_una) { - tp->t_timer[TCPT_REXMT] = tp->t_rxtcur; + ((sack_rxmit && tp->snd_nxt != tp->snd_max) || + tp->snd_nxt != tp->snd_una || (flags & TH_FIN))) { if (tp->t_timer[TCPT_PERSIST]) { tp->t_timer[TCPT_PERSIST] = 0; - tp->t_rxtshift = 0; + tp->t_persist_stop = 0; + TCP_RESET_REXMT_STATE(tp); } + tp->t_timer[TCPT_REXMT] = + OFFSET_FROM_START(tp, tp->t_rxtcur); } - } else - if (SEQ_GT(tp->snd_nxt + len, tp->snd_max)) + + /* + * Set tail loss probe timeout if new data is being + * transmitted. This will be supported only when + * SACK option is enabled on a connection. + * + * Every time new data is sent PTO will get reset. + */ + if (tcp_enable_tlp && len != 0 && tp->t_state == TCPS_ESTABLISHED && + SACK_ENABLED(tp) && !IN_FASTRECOVERY(tp) && + tp->snd_nxt == tp->snd_max && + SEQ_GT(tp->snd_nxt, tp->snd_una) && + tp->t_rxtshift == 0 && + (tp->t_flagsext & (TF_SENT_TLPROBE|TF_PKTS_REORDERED)) == 0) { + u_int32_t pto, srtt; + + /* + * Using SRTT alone to set PTO can cause spurious + * retransmissions on wireless networks where there + * is a lot of variance in RTT. Taking variance + * into account will avoid this. + */ + srtt = tp->t_srtt >> TCP_RTT_SHIFT; + pto = ((TCP_REXMTVAL(tp)) * 3) >> 1; + pto = max (2 * srtt, pto); + if ((tp->snd_max - tp->snd_una) == tp->t_maxseg) + pto = max(pto, + (((3 * pto) >> 2) + tcp_delack * 2)); + else + pto = max(10, pto); + + /* if RTO is less than PTO, choose RTO instead */ + if (tp->t_rxtcur < pto) + pto = tp->t_rxtcur; + + tp->t_timer[TCPT_PTO] = OFFSET_FROM_START(tp, pto); + } + } else { + /* + * Persist case, update snd_max but since we are in + * persist mode (no window) we do not update snd_nxt. + */ + int xlen = len; + if (flags & TH_SYN) + ++xlen; + if ((flags & TH_FIN) && + !(tp->t_flags & TF_SENTFIN)) { + ++xlen; + tp->t_flags |= TF_SENTFIN; + } + if (SEQ_GT(tp->snd_nxt + xlen, tp->snd_max)) { tp->snd_max = tp->snd_nxt + len; + tp->t_sndtime = tcp_now; + } + } #if TCPDEBUG /* * Trace. */ - if (so->so_options & SO_DEBUG) { -#if INET6 - if (isipv6) - ip6->ip6_vfc = IPV6_VERSION; - else - ip->ip_vhl = IP_MAKE_VHL(IPVERSION, - IP_VHL_HL(ip->ip_vhl)); -#endif /* INET6 */ - tcp_trace(TA_OUTPUT, tp->t_state, tp, -#if INET6 - isipv6 ? (void *)ip6 : -#endif /* INET6 */ - ip, - th, 0); - - } -#endif /* TCPDEBUG */ + if (so_options & SO_DEBUG) + tcp_trace(TA_OUTPUT, tp->t_state, tp, mtod(m, void *), th, 0); +#endif /* * Fill in IP length and desired time to live and @@ -812,139 +2350,792 @@ send: * the template, but need a way to checksum without them. */ #if INET6 + /* + * m->m_pkthdr.len should have been set before cksum calcuration, + * because in6_cksum() need it. + */ if (isipv6) { - /* + /* * we separately set hoplimit for every segment, since the * user might want to change the value via setsockopt. * Also, desired default hop limit might be changed via * Neighbor Discovery. */ - ip6->ip6_hlim = in6_selecthlim(tp->t_inpcb, - tp->t_inpcb->in6p_route.ro_rt ? - tp->t_inpcb->in6p_route.ro_rt->rt_ifp - : NULL); + ip6->ip6_hlim = in6_selecthlim(inp, inp->in6p_route.ro_rt ? + inp->in6p_route.ro_rt->rt_ifp : NULL); /* TODO: IPv6 IP6TOS_ECT bit on */ -#if IPSEC - ipsec_setsocket(m, so); -#endif /*IPSEC*/ - error = ip6_output(m, - tp->t_inpcb->in6p_outputopts, - &tp->t_inpcb->in6p_route, - (so->so_options & SO_DONTROUTE) /* | IP6_DONTFRAG */, - NULL, NULL); + KERNEL_DEBUG(DBG_LAYER_BEG, + ((inp->inp_fport << 16) | inp->inp_lport), + (((inp->in6p_laddr.s6_addr16[0] & 0xffff) << 16) | + (inp->in6p_faddr.s6_addr16[0] & 0xffff)), + sendalot,0,0); } else #endif /* INET6 */ { -#if 1 - struct rtentry *rt; -#endif - ip->ip_len = m->m_pkthdr.len; + ip->ip_len = m->m_pkthdr.len; + ip->ip_ttl = inp->inp_ip_ttl; /* XXX */ + ip->ip_tos |= (inp->inp_ip_tos & ~IPTOS_ECN_MASK);/* XXX */ + KERNEL_DEBUG(DBG_LAYER_BEG, + ((inp->inp_fport << 16) | inp->inp_lport), + (((inp->inp_laddr.s_addr & 0xffff) << 16) | + (inp->inp_faddr.s_addr & 0xffff)), 0,0,0); + } + + /* + * See if we should do MTU discovery. + * Look at the flag updated on the following criterias: + * 1) Path MTU discovery is authorized by the sysctl + * 2) The route isn't set yet (unlikely but could happen) + * 3) The route is up + * 4) the MTU is not locked (if it is, then discovery has been + * disabled for that route) + */ #if INET6 - if (INP_CHECK_SOCKAF(so, AF_INET6)) - ip->ip_ttl = in6_selecthlim(tp->t_inpcb, - tp->t_inpcb->in6p_route.ro_rt ? - tp->t_inpcb->in6p_route.ro_rt->rt_ifp - : NULL); - else + if (!isipv6) #endif /* INET6 */ - ip->ip_ttl = tp->t_inpcb->inp_ip_ttl; /* XXX */ - ip->ip_tos = tp->t_inpcb->inp_ip_tos; /* XXX */ + if (path_mtu_discovery && (tp->t_flags & TF_PMTUD)) + ip->ip_off |= IP_DF; + +#if NECP + { + necp_kernel_policy_id policy_id; + necp_kernel_policy_id skip_policy_id; + u_int32_t route_rule_id; + if (!necp_socket_is_allowed_to_send_recv(inp, &policy_id, &route_rule_id, &skip_policy_id)) { + m_freem(m); + error = EHOSTUNREACH; + goto out; + } + necp_mark_packet_from_socket(m, inp, policy_id, route_rule_id, skip_policy_id); -#define thtoti(x) \ - ((struct tcpiphdr *)(((char *)(x)) - (sizeof (struct ip)))) + if (net_qos_policy_restricted != 0) { + necp_socket_update_qos_marking(inp, inp->inp_route.ro_rt, + NULL, route_rule_id); + } + } +#endif /* NECP */ - KERNEL_DEBUG(DBG_LAYER_END, ((th->th_dport << 16) | th->th_sport), - (((thtoti(th)->ti_src.s_addr & 0xffff) << 16) | (thtoti(th)->ti_dst.s_addr & 0xffff)), - th->th_seq, th->th_ack, th->th_win); +#if IPSEC + if (inp->inp_sp != NULL) + ipsec_setsocket(m, so); +#endif /*IPSEC*/ + /* + * The socket is kept locked while sending out packets in ip_output, even if packet chaining is not active. + */ + lost = 0; -#if 1 /* - * See if we should do MTU discovery. We do it only if the following - * are true: - * 1) we have a valid route to the destination - * 2) the MTU is not locked (if it is, then discovery has been - * disabled) + * Embed the flow hash in pkt hdr and mark the packet as + * capable of flow controlling */ - if ((rt = tp->t_inpcb->inp_route.ro_rt) - && rt->rt_flags & RTF_UP - && !(rt->rt_rmx.rmx_locks & RTV_MTU)) { - ip->ip_off |= IP_DF; + m->m_pkthdr.pkt_flowsrc = FLOWSRC_INPCB; + m->m_pkthdr.pkt_flowid = inp->inp_flowhash; + m->m_pkthdr.pkt_flags |= (PKTF_FLOW_ID | PKTF_FLOW_LOCALSRC | PKTF_FLOW_ADV); + m->m_pkthdr.pkt_proto = IPPROTO_TCP; + m->m_pkthdr.tx_tcp_pid = so->last_pid; + if (so->so_flags & SOF_DELEGATED) + m->m_pkthdr.tx_tcp_e_pid = so->e_pid; + else + m->m_pkthdr.tx_tcp_e_pid = 0; + + m->m_nextpkt = NULL; + + if (inp->inp_last_outifp != NULL && + !(inp->inp_last_outifp->if_flags & IFF_LOOPBACK)) { + /* Hint to prioritize this packet if + * 1. if the packet has no data + * 2. the interface supports transmit-start model and did + * not disable ACK prioritization. + * 3. Only ACK flag is set. + * 4. there is no outstanding data on this connection. + */ + if (tcp_prioritize_acks != 0 && len == 0 && + (inp->inp_last_outifp->if_eflags & + (IFEF_TXSTART | IFEF_NOACKPRI)) == IFEF_TXSTART) { + if (th->th_flags == TH_ACK && + tp->snd_una == tp->snd_max && + tp->t_timer[TCPT_REXMT] == 0) + svc_flags |= PKT_SCF_TCP_ACK; + if (th->th_flags & TH_SYN) + svc_flags |= PKT_SCF_TCP_SYN; + } + set_packet_service_class(m, so, sotc, svc_flags); + } else { + /* + * Optimization for loopback just set the mbuf + * service class + */ + (void) m_set_service_class(m, so_tc2msc(sotc)); } -#endif -#if IPSEC - ipsec_setsocket(m, so); -#endif /*IPSEC*/ + tp->t_pktlist_sentlen += len; + tp->t_lastchain++; - error = ip_output(m, tp->t_inpcb->inp_options, &tp->t_inpcb->inp_route, - so->so_options & SO_DONTROUTE, 0); - } +#if INET6 + if (isipv6) { + DTRACE_TCP5(send, struct mbuf *, m, struct inpcb *, inp, + struct ip6 *, ip6, struct tcpcb *, tp, struct tcphdr *, + th); + } else +#endif /* INET6 */ + { + DTRACE_TCP5(send, struct mbuf *, m, struct inpcb *, inp, + struct ip *, ip, struct tcpcb *, tp, struct tcphdr *, th); + } + + if (tp->t_pktlist_head != NULL) { + tp->t_pktlist_tail->m_nextpkt = m; + tp->t_pktlist_tail = m; + } else { + packchain_newlist++; + tp->t_pktlist_head = tp->t_pktlist_tail = m; + } + + if ((lro_ackmore) && (!sackoptlen) && (!tp->t_timer[TCPT_PERSIST]) && + ((th->th_flags & TH_ACK) == TH_ACK) && (!len) && + (tp->t_state == TCPS_ESTABLISHED)) { + /* For a pure ACK, see if you need to send more of them */ + mnext = tcp_send_lroacks(tp, m, th); + if (mnext) { + tp->t_pktlist_tail->m_nextpkt = mnext; + if (mnext->m_nextpkt == NULL) { + tp->t_pktlist_tail = mnext; + tp->t_lastchain++; + } else { + struct mbuf *tail, *next; + next = mnext->m_nextpkt; + tail = next->m_nextpkt; + while (tail) { + next = tail; + tail = tail->m_nextpkt; + tp->t_lastchain++; + } + tp->t_pktlist_tail = next; + } + } + } + + if (sendalot == 0 || (tp->t_state != TCPS_ESTABLISHED) || + (tp->snd_cwnd <= (tp->snd_wnd / 8)) || + (tp->t_flags & TF_ACKNOW) || + (tp->t_flagsext & TF_FORCE) || + tp->t_lastchain >= tcp_packet_chaining) { + error = 0; + while (inp->inp_sndinprog_cnt == 0 && + tp->t_pktlist_head != NULL) { + packetlist = tp->t_pktlist_head; + packchain_listadd = tp->t_lastchain; + packchain_sent++; + lost = tp->t_pktlist_sentlen; + TCP_PKTLIST_CLEAR(tp); + + error = tcp_ip_output(so, tp, packetlist, + packchain_listadd, tp_inp_options, + (so_options & SO_DONTROUTE), + (sack_rxmit || (sack_bytes_rxmt != 0)), isipv6); + if (error) { + /* + * Take into account the rest of unsent + * packets in the packet list for this tcp + * into "lost", since we're about to free + * the whole list below. + */ + lost += tp->t_pktlist_sentlen; + break; + } else { + lost = 0; + } + } + /* tcp was closed while we were in ip; resume close */ + if (inp->inp_sndinprog_cnt == 0 && + (tp->t_flags & TF_CLOSING)) { + tp->t_flags &= ~TF_CLOSING; + (void) tcp_close(tp); + return (0); + } + } else { + error = 0; + packchain_looped++; + tcpstat.tcps_sndtotal++; + + goto again; + } if (error) { + /* + * Assume that the packets were lost, so back out the + * sequence number advance, if any. Note that the "lost" + * variable represents the amount of user data sent during + * the recent call to ip_output_list() plus the amount of + * user data in the packet list for this tcp at the moment. + */ + if (!(tp->t_flagsext & TF_FORCE) + || tp->t_timer[TCPT_PERSIST] == 0) { + /* + * No need to check for TH_FIN here because + * the TF_SENTFIN flag handles that case. + */ + if ((flags & TH_SYN) == 0) { + if (sack_rxmit) { + if (SEQ_GT((p->rxmit - lost), + tp->snd_una)) { + p->rxmit -= lost; + } else { + lost = p->rxmit - tp->snd_una; + p->rxmit = tp->snd_una; + } + tp->sackhint.sack_bytes_rexmit -= lost; + } else { + if (SEQ_GT((tp->snd_nxt - lost), + tp->snd_una)) + tp->snd_nxt -= lost; + else + tp->snd_nxt = tp->snd_una; + } + } + } out: + if (tp->t_pktlist_head != NULL) + m_freem_list(tp->t_pktlist_head); + TCP_PKTLIST_CLEAR(tp); + if (error == ENOBUFS) { - if (!tp->t_timer[TCPT_REXMT] && - !tp->t_timer[TCPT_PERSIST]) - tp->t_timer[TCPT_REXMT] = tp->t_rxtcur; - tcp_quench(tp->t_inpcb, 0); + /* + * Set retransmit timer if not currently set + * when we failed to send a segment that can be + * retransmitted (i.e. not pure ack or rst) + */ + if (!tp->t_timer[TCPT_REXMT] && + !tp->t_timer[TCPT_PERSIST] && + (len != 0 || (flags & (TH_SYN | TH_FIN)) != 0 || + so->so_snd.sb_cc > 0)) + tp->t_timer[TCPT_REXMT] = + OFFSET_FROM_START(tp, tp->t_rxtcur); + tp->snd_cwnd = tp->t_maxseg; + tp->t_bytes_acked = 0; + tcp_check_timer_state(tp); KERNEL_DEBUG(DBG_FNC_TCP_OUTPUT | DBG_FUNC_END, 0,0,0,0,0); + + tcp_ccdbg_trace(tp, NULL, TCP_CC_OUTPUT_ERROR); return (0); } -#if 1 if (error == EMSGSIZE) { /* * ip_output() will have already fixed the route * for us. tcp_mtudisc() will, as its last action, * initiate retransmission, so it is important to * not do so here. + * + * If TSO was active we either got an interface + * without TSO capabilits or TSO was turned off. + * Disable it for this connection as too and + * immediatly retry with MSS sized segments generated + * by this function. */ - tcp_mtudisc(tp->t_inpcb, 0); + if (tso) + tp->t_flags &= ~TF_TSO; + + tcp_mtudisc(inp, 0); + tcp_check_timer_state(tp); + KERNEL_DEBUG(DBG_FNC_TCP_OUTPUT | DBG_FUNC_END, 0,0,0,0,0); return 0; } -#endif - if ((error == EHOSTUNREACH || error == ENETDOWN) - && TCPS_HAVERCVDSYN(tp->t_state)) { - tp->t_softerror = error; - KERNEL_DEBUG(DBG_FNC_TCP_OUTPUT | DBG_FUNC_END, 0,0,0,0,0); - return (0); + /* + * Unless this is due to interface restriction policy, + * treat EHOSTUNREACH/ENETDOWN as a soft error. + */ + if ((error == EHOSTUNREACH || error == ENETDOWN) && + TCPS_HAVERCVDSYN(tp->t_state) && + !inp_restricted_send(inp, inp->inp_last_outifp)) { + tp->t_softerror = error; + error = 0; } + tcp_check_timer_state(tp); KERNEL_DEBUG(DBG_FNC_TCP_OUTPUT | DBG_FUNC_END, 0,0,0,0,0); return (error); } + tcpstat.tcps_sndtotal++; - /* - * Data sent (as far as we can tell). - * If this advertises a larger window than any other segment, - * then remember the size of the advertised window. - * Any pending ACK has now been sent. - */ - if (win > 0 && SEQ_GT(tp->rcv_nxt+win, tp->rcv_adv)) - tp->rcv_adv = tp->rcv_nxt + win; - tp->last_ack_sent = tp->rcv_nxt; - tp->t_flags &= ~(TF_ACKNOW|TF_DELACK); + KERNEL_DEBUG(DBG_FNC_TCP_OUTPUT | DBG_FUNC_END,0,0,0,0,0); if (sendalot) goto again; - KERNEL_DEBUG(DBG_FNC_TCP_OUTPUT | DBG_FUNC_END, 0,0,0,0,0); + + tcp_check_timer_state(tp); return (0); } +static int +tcp_ip_output(struct socket *so, struct tcpcb *tp, struct mbuf *pkt, + int cnt, struct mbuf *opt, int flags, int sack_in_progress, boolean_t isipv6) +{ + int error = 0; + boolean_t chain; + boolean_t unlocked = FALSE; + boolean_t ifdenied = FALSE; + struct inpcb *inp = tp->t_inpcb; + struct ip_out_args ipoa; + struct route ro; + struct ifnet *outif = NULL; + + bzero(&ipoa, sizeof(ipoa)); + ipoa.ipoa_boundif = IFSCOPE_NONE; + ipoa.ipoa_flags = IPOAF_SELECT_SRCIF | IPOAF_BOUND_SRCADDR; + ipoa.ipoa_sotc = SO_TC_UNSPEC; + ipoa.ipoa_netsvctype = _NET_SERVICE_TYPE_UNSPEC; +#if INET6 + struct ip6_out_args ip6oa; + struct route_in6 ro6; + + bzero(&ip6oa, sizeof(ip6oa)); + ip6oa.ip6oa_boundif = IFSCOPE_NONE; + ip6oa.ip6oa_flags = IP6OAF_SELECT_SRCIF | IP6OAF_BOUND_SRCADDR; + ip6oa.ip6oa_sotc = SO_TC_UNSPEC; + ip6oa.ip6oa_netsvctype = _NET_SERVICE_TYPE_UNSPEC; + + struct flowadv *adv = + (isipv6 ? &ip6oa.ip6oa_flowadv : &ipoa.ipoa_flowadv); +#else /* INET6 */ + struct flowadv *adv = &ipoa.ipoa_flowadv; +#endif /* !INET6 */ + + /* If socket was bound to an ifindex, tell ip_output about it */ + if (inp->inp_flags & INP_BOUND_IF) { +#if INET6 + if (isipv6) { + ip6oa.ip6oa_boundif = inp->inp_boundifp->if_index; + ip6oa.ip6oa_flags |= IP6OAF_BOUND_IF; + } else +#endif /* INET6 */ + { + ipoa.ipoa_boundif = inp->inp_boundifp->if_index; + ipoa.ipoa_flags |= IPOAF_BOUND_IF; + } + } + + if (INP_NO_CELLULAR(inp)) { +#if INET6 + if (isipv6) + ip6oa.ip6oa_flags |= IP6OAF_NO_CELLULAR; + else +#endif /* INET6 */ + ipoa.ipoa_flags |= IPOAF_NO_CELLULAR; + } + if (INP_NO_EXPENSIVE(inp)) { +#if INET6 + if (isipv6) + ip6oa.ip6oa_flags |= IP6OAF_NO_EXPENSIVE; + else +#endif /* INET6 */ + ipoa.ipoa_flags |= IPOAF_NO_EXPENSIVE; + + } + if (INP_AWDL_UNRESTRICTED(inp)) { +#if INET6 + if (isipv6) + ip6oa.ip6oa_flags |= IP6OAF_AWDL_UNRESTRICTED; + else +#endif /* INET6 */ + ipoa.ipoa_flags |= IPOAF_AWDL_UNRESTRICTED; + + } +#if INET6 + if (INP_INTCOPROC_ALLOWED(inp) && isipv6) { + ip6oa.ip6oa_flags |= IP6OAF_INTCOPROC_ALLOWED; + } + if (isipv6) { + ip6oa.ip6oa_sotc = so->so_traffic_class; + ip6oa.ip6oa_netsvctype = so->so_netsvctype; + } else +#endif /* INET6 */ + { + ipoa.ipoa_sotc = so->so_traffic_class; + ipoa.ipoa_netsvctype = so->so_netsvctype; + } + if ((so->so_flags1 & SOF1_QOSMARKING_ALLOWED)) { +#if INET6 + if (isipv6) + ip6oa.ip6oa_flags |= IP6OAF_QOSMARKING_ALLOWED; + else +#endif /* INET6 */ + ipoa.ipoa_flags |= IPOAF_QOSMARKING_ALLOWED; + } +#if INET6 + if (isipv6) + flags |= IPV6_OUTARGS; + else +#endif /* INET6 */ + flags |= IP_OUTARGS; + + /* Copy the cached route and take an extra reference */ +#if INET6 + if (isipv6) + in6p_route_copyout(inp, &ro6); + else +#endif /* INET6 */ + inp_route_copyout(inp, &ro); + + /* + * Make sure ACK/DELACK conditions are cleared before + * we unlock the socket. + */ + tp->last_ack_sent = tp->rcv_nxt; + tp->t_flags &= ~(TF_ACKNOW | TF_DELACK); + tp->t_timer[TCPT_DELACK] = 0; + tp->t_unacksegs = 0; + + /* Increment the count of outstanding send operations */ + inp->inp_sndinprog_cnt++; + + /* + * If allowed, unlock TCP socket while in IP + * but only if the connection is established and + * in a normal mode where reentrancy on the tcpcb won't be + * an issue: + * - there is no SACK episode + * - we're not in Fast Recovery mode + * - if we're not sending from an upcall. + */ + if (tcp_output_unlocked && !so->so_upcallusecount && + (tp->t_state == TCPS_ESTABLISHED) && (sack_in_progress == 0) && + !IN_FASTRECOVERY(tp) && !(so->so_flags & SOF_MP_SUBFLOW)) { + + unlocked = TRUE; + socket_unlock(so, 0); + } + + /* + * Don't send down a chain of packets when: + * - TCP chaining is disabled + * - there is an IPsec rule set + * - there is a non default rule set for the firewall + */ + + chain = tcp_packet_chaining > 1 +#if IPSEC + && ipsec_bypass +#endif +#if IPFIREWALL + && (fw_enable == 0 || fw_bypass) +#endif + ; // I'm important, not extraneous + + + while (pkt != NULL) { + struct mbuf *npkt = pkt->m_nextpkt; + + if (!chain) { + pkt->m_nextpkt = NULL; + /* + * If we are not chaining, make sure to set the packet + * list count to 0 so that IP takes the right path; + * this is important for cases such as IPSec where a + * single mbuf might result in multiple mbufs as part + * of the encapsulation. If a non-zero count is passed + * down to IP, the head of the chain might change and + * we could end up skipping it (thus generating bogus + * packets). Fixing it in IP would be desirable, but + * for now this would do it. + */ + cnt = 0; + } +#if INET6 + if (isipv6) { + error = ip6_output_list(pkt, cnt, + inp->in6p_outputopts, &ro6, flags, NULL, NULL, + &ip6oa); + ifdenied = (ip6oa.ip6oa_retflags & IP6OARF_IFDENIED); + } else { +#endif /* INET6 */ + error = ip_output_list(pkt, cnt, opt, &ro, flags, NULL, + &ipoa); + ifdenied = (ipoa.ipoa_retflags & IPOARF_IFDENIED); + } + + if (chain || error) { + /* + * If we sent down a chain then we are done since + * the callee had taken care of everything; else + * we need to free the rest of the chain ourselves. + */ + if (!chain) + m_freem_list(npkt); + break; + } + pkt = npkt; + } + + if (unlocked) + socket_lock(so, 0); + + /* + * Enter flow controlled state if the connection is established + * and is not in recovery. Flow control is allowed only if there + * is outstanding data. + * + * A connection will enter suspended state even if it is in + * recovery. + */ + if (((adv->code == FADV_FLOW_CONTROLLED && !IN_FASTRECOVERY(tp)) || + adv->code == FADV_SUSPENDED) && + !(tp->t_flags & TF_CLOSING) && + tp->t_state == TCPS_ESTABLISHED && + SEQ_GT(tp->snd_max, tp->snd_una)) { + int rc; + rc = inp_set_fc_state(inp, adv->code); + + if (rc == 1) + tcp_ccdbg_trace(tp, NULL, + ((adv->code == FADV_FLOW_CONTROLLED) ? + TCP_CC_FLOW_CONTROL : TCP_CC_SUSPEND)); + } + + /* + * When an interface queue gets suspended, some of the + * packets are dropped. Return ENOBUFS, to update the + * pcb state. + */ + if (adv->code == FADV_SUSPENDED) + error = ENOBUFS; + + VERIFY(inp->inp_sndinprog_cnt > 0); + if ( --inp->inp_sndinprog_cnt == 0) + inp->inp_flags &= ~(INP_FC_FEEDBACK); + +#if INET6 + if (isipv6) { + if (ro6.ro_rt != NULL) + outif = ro6.ro_rt->rt_ifp; + } else +#endif /* INET6 */ + if (ro.ro_rt != NULL) + outif = ro.ro_rt->rt_ifp; + + if (outif != NULL && outif != inp->inp_last_outifp && + so->so_snd.sb_cc > 0) { + /* Update the send byte count */ + if (so->so_snd.sb_flags & SB_SNDBYTE_CNT) { + inp_decr_sndbytes_total(so, so->so_snd.sb_cc); + inp_decr_sndbytes_allunsent(so, tp->snd_una); + so->so_snd.sb_flags &= ~SB_SNDBYTE_CNT; + } + inp->inp_last_outifp = outif; + + } + + if (error != 0 && ifdenied && + (INP_NO_CELLULAR(inp) || INP_NO_EXPENSIVE(inp))) + soevent(so, + (SO_FILT_HINT_LOCKED|SO_FILT_HINT_IFDENIED)); + + /* Synchronize cached PCB route & options */ +#if INET6 + if (isipv6) + in6p_route_copyin(inp, &ro6); + else +#endif /* INET6 */ + inp_route_copyin(inp, &ro); + + if (tp->t_state < TCPS_ESTABLISHED && tp->t_rxtshift == 0 && + tp->t_inpcb->inp_route.ro_rt != NULL) { + /* If we found the route and there is an rtt on it + * reset the retransmit timer + */ + tcp_getrt_rtt(tp, tp->t_inpcb->in6p_route.ro_rt); + tp->t_timer[TCPT_REXMT] = OFFSET_FROM_START(tp, tp->t_rxtcur); + } + return (error); +} + +int tcptv_persmin_val = TCPTV_PERSMIN; + void -tcp_setpersist(tp) - register struct tcpcb *tp; +tcp_setpersist(struct tcpcb *tp) { - register int t = ((tp->t_srtt >> 2) + tp->t_rttvar) >> 1; + int t = ((tp->t_srtt >> 2) + tp->t_rttvar) >> 1; + + /* If a PERSIST_TIMER option was set we will limit the + * time the persist timer will be active for that connection + * in order to avoid DOS by using zero window probes. + * see rdar://5805356 + */ + + if ((tp->t_persist_timeout != 0) && + (tp->t_timer[TCPT_PERSIST] == 0) && + (tp->t_persist_stop == 0)) { + tp->t_persist_stop = tcp_now + tp->t_persist_timeout; + } - if (tp->t_timer[TCPT_REXMT]) - panic("tcp_output REXMT"); /* * Start/restart persistance timer. */ TCPT_RANGESET(tp->t_timer[TCPT_PERSIST], t * tcp_backoff[tp->t_rxtshift], - TCPTV_PERSMIN, TCPTV_PERSMAX); + tcptv_persmin_val, TCPTV_PERSMAX, 0); + tp->t_timer[TCPT_PERSIST] = OFFSET_FROM_START(tp, tp->t_timer[TCPT_PERSIST]); + if (tp->t_rxtshift < TCP_MAXRXTSHIFT) tp->t_rxtshift++; } + +/* + * Send as many acks as data coalesced. Every other packet when stretch + * ACK is not enabled. Every 8 packets, if stretch ACK is enabled. + */ +static struct mbuf* +tcp_send_lroacks(struct tcpcb *tp, struct mbuf *m, struct tcphdr *th) +{ + struct mbuf *mnext = NULL, *ack_chain = NULL, *tail = NULL; + int count = 0; + tcp_seq org_ack = ntohl(th->th_ack); + tcp_seq prev_ack = 0; + int tack_offset = 28; /* IPv6 and IP options not supported */ + int twin_offset = 34; /* IPv6 and IP options not supported */ + int ack_size = (tp->t_flags & TF_STRETCHACK) ? + (maxseg_unacked * tp->t_maxseg) : (tp->t_maxseg << 1); + int segs_acked = (tp->t_flags & TF_STRETCHACK) ? maxseg_unacked : 2; + struct mbuf *prev_ack_pkt = NULL; + struct socket *so = tp->t_inpcb->inp_socket; + unsigned short winsz = ntohs(th->th_win); + unsigned int scaled_win = winsz<rcv_scale; + tcp_seq win_rtedge = org_ack + scaled_win; + + count = tp->t_lropktlen/tp->t_maxseg; + + prev_ack = (org_ack - tp->t_lropktlen) + ack_size; + if (prev_ack < org_ack) { + ack_chain = m_dup(m, M_DONTWAIT); + if (ack_chain) { + th->th_ack = htonl(prev_ack); + /* Keep adv window constant for duplicated ACK packets */ + scaled_win = win_rtedge - prev_ack; + if (scaled_win > (int32_t)(TCP_MAXWIN << tp->rcv_scale)) + scaled_win = (int32_t)(TCP_MAXWIN << tp->rcv_scale); + th->th_win = htons(scaled_win>>tp->rcv_scale); + if (lrodebug == 5) { + printf("%s: win = %d winsz = %d sc = %d" + " lro_len %d %d\n", + __func__, scaled_win>>tp->rcv_scale, winsz, + tp->rcv_scale, tp->t_lropktlen, count); + } + tail = ack_chain; + count -= segs_acked; /* accounts for prev_ack packet */ + count = (count <= segs_acked) ? 0 : count - segs_acked; + tcpstat.tcps_sndacks++; + so_tc_update_stats(m, so, m_get_service_class(m)); + } else { + return NULL; + } + } + else { + tp->t_lropktlen = 0; + return NULL; + } + + prev_ack_pkt = ack_chain; + + while (count > 0) { + if ((prev_ack + ack_size) < org_ack) { + prev_ack += ack_size; + } else { + /* + * The last ACK sent must have the ACK number that TCP + * thinks is the last sent ACK number. + */ + prev_ack = org_ack; + } + mnext = m_dup(prev_ack_pkt, M_DONTWAIT); + if (mnext) { + /* Keep adv window constant for duplicated ACK packets */ + scaled_win = win_rtedge - prev_ack; + if (scaled_win > (int32_t)(TCP_MAXWIN << tp->rcv_scale)) + scaled_win = (int32_t)(TCP_MAXWIN << tp->rcv_scale); + winsz = htons(scaled_win>>tp->rcv_scale); + if (lrodebug == 5) { + printf("%s: winsz = %d ack %x count %d\n", + __func__, scaled_win>>tp->rcv_scale, + prev_ack, count); + } + bcopy(&winsz, mtod(prev_ack_pkt, caddr_t) + twin_offset, 2); + HTONL(prev_ack); + bcopy(&prev_ack, mtod(prev_ack_pkt, caddr_t) + tack_offset, 4); + NTOHL(prev_ack); + tail->m_nextpkt = mnext; + tail = mnext; + count -= segs_acked; + tcpstat.tcps_sndacks++; + so_tc_update_stats(m, so, m_get_service_class(m)); + } else { + if (lrodebug == 5) { + printf("%s: failed to alloc mbuf.\n", __func__); + } + break; + } + prev_ack_pkt = mnext; + } + tp->t_lropktlen = 0; + return ack_chain; +} + +static int +tcp_recv_throttle (struct tcpcb *tp) +{ + uint32_t base_rtt, newsize; + struct sockbuf *sbrcv = &tp->t_inpcb->inp_socket->so_rcv; + + if (tcp_use_rtt_recvbg == 1 && + TSTMP_SUPPORTED(tp)) { + /* + * Timestamps are supported on this connection. Use + * RTT to look for an increase in latency. + */ + + /* + * If the connection is already being throttled, leave it + * in that state until rtt comes closer to base rtt + */ + if (tp->t_flagsext & TF_RECV_THROTTLE) + return (1); + + base_rtt = get_base_rtt(tp); + + if (base_rtt != 0 && tp->t_rttcur != 0) { + /* + * if latency increased on a background flow, + * return 1 to start throttling. + */ + if (tp->t_rttcur > (base_rtt + target_qdelay)) { + tp->t_flagsext |= TF_RECV_THROTTLE; + if (tp->t_recv_throttle_ts == 0) + tp->t_recv_throttle_ts = tcp_now; + /* + * Reduce the recv socket buffer size to + * minimize latecy. + */ + if (sbrcv->sb_idealsize > + tcp_recv_throttle_minwin) { + newsize = sbrcv->sb_idealsize >> 1; + /* Set a minimum of 16 K */ + newsize = + max(newsize, + tcp_recv_throttle_minwin); + sbrcv->sb_idealsize = newsize; + } + return (1); + } else { + return (0); + } + } + } + + /* + * Timestamps are not supported or there is no good RTT + * measurement. Use IPDV in this case. + */ + if (tp->acc_iaj > tcp_acc_iaj_react_limit) + return (1); + + return (0); +}