File:  [DragonFly] / src / sys / netinet / tcp_subr.c
Revision 1.21: download - view: text, annotated - select for diffs
Fri Apr 9 22:34:10 2004 UTC (10 years, 5 months ago) by hsu
Branches: MAIN
CVS tags: HEAD
Push the lwkt_replymsg() up one level from netisr_service_loop() to
the message handler so we can explicitly reply or not reply as appropriate.

    1: /*
    2:  * Copyright (c) 1982, 1986, 1988, 1990, 1993, 1995
    3:  *	The Regents of the University of California.  All rights reserved.
    4:  *
    5:  * Redistribution and use in source and binary forms, with or without
    6:  * modification, are permitted provided that the following conditions
    7:  * are met:
    8:  * 1. Redistributions of source code must retain the above copyright
    9:  *    notice, this list of conditions and the following disclaimer.
   10:  * 2. Redistributions in binary form must reproduce the above copyright
   11:  *    notice, this list of conditions and the following disclaimer in the
   12:  *    documentation and/or other materials provided with the distribution.
   13:  * 3. All advertising materials mentioning features or use of this software
   14:  *    must display the following acknowledgement:
   15:  *	This product includes software developed by the University of
   16:  *	California, Berkeley and its contributors.
   17:  * 4. Neither the name of the University nor the names of its contributors
   18:  *    may be used to endorse or promote products derived from this software
   19:  *    without specific prior written permission.
   20:  *
   21:  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   22:  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   23:  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   24:  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   25:  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   26:  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   27:  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   28:  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   29:  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   30:  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   31:  * SUCH DAMAGE.
   32:  *
   33:  *	@(#)tcp_subr.c	8.2 (Berkeley) 5/24/95
   34:  * $FreeBSD: src/sys/netinet/tcp_subr.c,v 1.73.2.31 2003/01/24 05:11:34 sam Exp $
   35:  * $DragonFly: src/sys/netinet/tcp_subr.c,v 1.21 2004/04/09 22:34:10 hsu Exp $
   36:  */
   37: 
   38: #include "opt_compat.h"
   39: #include "opt_inet6.h"
   40: #include "opt_ipsec.h"
   41: #include "opt_tcpdebug.h"
   42: 
   43: #include <sys/param.h>
   44: #include <sys/systm.h>
   45: #include <sys/callout.h>
   46: #include <sys/kernel.h>
   47: #include <sys/sysctl.h>
   48: #include <sys/malloc.h>
   49: #include <sys/mbuf.h>
   50: #ifdef INET6
   51: #include <sys/domain.h>
   52: #endif
   53: #include <sys/proc.h>
   54: #include <sys/socket.h>
   55: #include <sys/socketvar.h>
   56: #include <sys/protosw.h>
   57: #include <sys/random.h>
   58: #include <sys/in_cksum.h>
   59: 
   60: #include <vm/vm_zone.h>
   61: 
   62: #include <net/route.h>
   63: #include <net/if.h>
   64: #include <net/netisr.h>
   65: 
   66: #define _IP_VHL
   67: #include <netinet/in.h>
   68: #include <netinet/in_systm.h>
   69: #include <netinet/ip.h>
   70: #ifdef INET6
   71: #include <netinet/ip6.h>
   72: #endif
   73: #include <netinet/in_pcb.h>
   74: #ifdef INET6
   75: #include <netinet6/in6_pcb.h>
   76: #endif
   77: #include <netinet/in_var.h>
   78: #include <netinet/ip_var.h>
   79: #ifdef INET6
   80: #include <netinet6/ip6_var.h>
   81: #endif
   82: #include <netinet/tcp.h>
   83: #include <netinet/tcp_fsm.h>
   84: #include <netinet/tcp_seq.h>
   85: #include <netinet/tcp_timer.h>
   86: #include <netinet/tcp_var.h>
   87: #ifdef INET6
   88: #include <netinet6/tcp6_var.h>
   89: #endif
   90: #include <netinet/tcpip.h>
   91: #ifdef TCPDEBUG
   92: #include <netinet/tcp_debug.h>
   93: #endif
   94: #include <netinet6/ip6protosw.h>
   95: 
   96: #ifdef IPSEC
   97: #include <netinet6/ipsec.h>
   98: #ifdef INET6
   99: #include <netinet6/ipsec6.h>
  100: #endif
  101: #endif /*IPSEC*/
  102: 
  103: #ifdef FAST_IPSEC
  104: #include <netipsec/ipsec.h>
  105: #ifdef INET6
  106: #include <netipsec/ipsec6.h>
  107: #endif
  108: #define	IPSEC
  109: #endif /*FAST_IPSEC*/
  110: 
  111: #include <sys/md5.h>
  112: 
  113: #include <sys/msgport2.h>
  114: 
  115: int 	tcp_mssdflt = TCP_MSS;
  116: SYSCTL_INT(_net_inet_tcp, TCPCTL_MSSDFLT, mssdflt, CTLFLAG_RW, 
  117:     &tcp_mssdflt , 0, "Default TCP Maximum Segment Size");
  118: 
  119: #ifdef INET6
  120: int	tcp_v6mssdflt = TCP6_MSS;
  121: SYSCTL_INT(_net_inet_tcp, TCPCTL_V6MSSDFLT, v6mssdflt,
  122: 	CTLFLAG_RW, &tcp_v6mssdflt , 0,
  123: 	"Default TCP Maximum Segment Size for IPv6");
  124: #endif
  125: 
  126: #if 0
  127: static int 	tcp_rttdflt = TCPTV_SRTTDFLT / PR_SLOWHZ;
  128: SYSCTL_INT(_net_inet_tcp, TCPCTL_RTTDFLT, rttdflt, CTLFLAG_RW, 
  129:     &tcp_rttdflt , 0, "Default maximum TCP Round Trip Time");
  130: #endif
  131: 
  132: int	tcp_do_rfc1323 = 1;
  133: SYSCTL_INT(_net_inet_tcp, TCPCTL_DO_RFC1323, rfc1323, CTLFLAG_RW, 
  134:     &tcp_do_rfc1323 , 0, "Enable rfc1323 (high performance TCP) extensions");
  135: 
  136: int	tcp_do_rfc1644 = 0;
  137: SYSCTL_INT(_net_inet_tcp, TCPCTL_DO_RFC1644, rfc1644, CTLFLAG_RW, 
  138:     &tcp_do_rfc1644 , 0, "Enable rfc1644 (TTCP) extensions");
  139: 
  140: static int	tcp_tcbhashsize = 0;
  141: SYSCTL_INT(_net_inet_tcp, OID_AUTO, tcbhashsize, CTLFLAG_RD,
  142:      &tcp_tcbhashsize, 0, "Size of TCP control-block hashtable");
  143: 
  144: static int	do_tcpdrain = 1;
  145: SYSCTL_INT(_net_inet_tcp, OID_AUTO, do_tcpdrain, CTLFLAG_RW, &do_tcpdrain, 0,
  146:      "Enable tcp_drain routine for extra help when low on mbufs");
  147: 
  148: /* XXX JH */
  149: SYSCTL_INT(_net_inet_tcp, OID_AUTO, pcbcount, CTLFLAG_RD, 
  150:     &tcbinfo[0].ipi_count, 0, "Number of active PCBs");
  151: 
  152: static int	icmp_may_rst = 1;
  153: SYSCTL_INT(_net_inet_tcp, OID_AUTO, icmp_may_rst, CTLFLAG_RW, &icmp_may_rst, 0, 
  154:     "Certain ICMP unreachable messages may abort connections in SYN_SENT");
  155: 
  156: static int	tcp_isn_reseed_interval = 0;
  157: SYSCTL_INT(_net_inet_tcp, OID_AUTO, isn_reseed_interval, CTLFLAG_RW,
  158:     &tcp_isn_reseed_interval, 0, "Seconds between reseeding of ISN secret");
  159: 
  160: /*
  161:  * TCP bandwidth limiting sysctls.  Note that the default lower bound of 
  162:  * 1024 exists only for debugging.  A good production default would be 
  163:  * something like 6100.
  164:  */
  165: static int     tcp_inflight_enable = 0;
  166: SYSCTL_INT(_net_inet_tcp, OID_AUTO, inflight_enable, CTLFLAG_RW,
  167:     &tcp_inflight_enable, 0, "Enable automatic TCP inflight data limiting");
  168: 
  169: static int     tcp_inflight_debug = 0;
  170: SYSCTL_INT(_net_inet_tcp, OID_AUTO, inflight_debug, CTLFLAG_RW,
  171:     &tcp_inflight_debug, 0, "Debug TCP inflight calculations");
  172: 
  173: static int     tcp_inflight_min = 6144;
  174: SYSCTL_INT(_net_inet_tcp, OID_AUTO, inflight_min, CTLFLAG_RW,
  175:     &tcp_inflight_min, 0, "Lower-bound for TCP inflight window");
  176: 
  177: static int     tcp_inflight_max = TCP_MAXWIN << TCP_MAX_WINSHIFT;
  178: SYSCTL_INT(_net_inet_tcp, OID_AUTO, inflight_max, CTLFLAG_RW,
  179:     &tcp_inflight_max, 0, "Upper-bound for TCP inflight window");
  180: 
  181: static int     tcp_inflight_stab = 20;
  182: SYSCTL_INT(_net_inet_tcp, OID_AUTO, inflight_stab, CTLFLAG_RW,
  183:     &tcp_inflight_stab, 0, "Slop in maximal packets / 10 (20 = 2 packets)");
  184: 
  185: static void	tcp_cleartaocache (void);
  186: static void	tcp_notify (struct inpcb *, int);
  187: 
  188: struct tcp_stats tcpstats_ary[MAXCPU];
  189: #ifdef SMP
  190: static int
  191: sysctl_tcpstats(SYSCTL_HANDLER_ARGS)
  192: {
  193: 	int cpu, error;
  194: 
  195: 	for (cpu = error = 0; cpu < ncpus; ++cpu) {
  196: 		if ((error = SYSCTL_OUT(req, (void *)&tcpstats_ary[cpu],
  197: 			sizeof(struct tcp_stats))))
  198: 			break;
  199: 		if ((error = SYSCTL_IN(req, (void *)&tcpstats_ary[cpu],
  200: 			sizeof(struct tcp_stats))))
  201: 			break;
  202: 	}
  203: 
  204: 	return (error);
  205: }
  206: SYSCTL_PROC(_net_inet_tcp, TCPCTL_STATS, stats, CTLTYPE_OPAQUE|CTLFLAG_RW,
  207:     0, 0, sysctl_tcpstats, "S,tcp_stats",
  208: 	"TCP statistics (struct tcp_stats, netinet/tcp_stats.h)");
  209: #else /* !SMP */
  210: SYSCTL_STRUCT(_net_inet_tcp, TCPCTL_STATS, stats, CTLFLAG_RW,
  211:     &tcpstat , tcp_stats,
  212: 	"TCP statistics (struct tcp_stats, netinet/tcp_stats.h)");
  213: #endif
  214: 
  215: /*
  216:  * Target size of TCP PCB hash tables. Must be a power of two.
  217:  *
  218:  * Note that this can be overridden by the kernel environment
  219:  * variable net.inet.tcp.tcbhashsize
  220:  */
  221: #ifndef TCBHASHSIZE
  222: #define TCBHASHSIZE	512
  223: #endif
  224: 
  225: /*
  226:  * This is the actual shape of what we allocate using the zone
  227:  * allocator.  Doing it this way allows us to protect both structures
  228:  * using the same generation count, and also eliminates the overhead
  229:  * of allocating tcpcbs separately.  By hiding the structure here,
  230:  * we avoid changing most of the rest of the code (although it needs
  231:  * to be changed, eventually, for greater efficiency).
  232:  */
  233: #define	ALIGNMENT	32
  234: #define	ALIGNM1		(ALIGNMENT - 1)
  235: struct	inp_tp {
  236: 	union {
  237: 		struct	inpcb inp;
  238: 		char	align[(sizeof(struct inpcb) + ALIGNM1) & ~ALIGNM1];
  239: 	} inp_tp_u;
  240: 	struct	tcpcb tcb;
  241: 	struct	callout inp_tp_rexmt, inp_tp_persist, inp_tp_keep, inp_tp_2msl;
  242: 	struct	callout inp_tp_delack;
  243: };
  244: #undef ALIGNMENT
  245: #undef ALIGNM1
  246: 
  247: /*
  248:  * Tcp initialization
  249:  */
  250: void
  251: tcp_init()
  252: {
  253: 	struct inpcbporthead *porthashbase;
  254: 	u_long porthashmask;
  255: 	struct inpcbhead *wildcardhashbase;
  256: 	u_long wildcardhashmask;
  257: 	struct vm_zone *ipi_zone;
  258: 	int hashsize = TCBHASHSIZE;
  259: 	int cpu;
  260: 
  261: 	tcp_ccgen = 1;
  262: 	tcp_cleartaocache();
  263: 
  264: 	tcp_delacktime = TCPTV_DELACK;
  265: 	tcp_keepinit = TCPTV_KEEP_INIT;
  266: 	tcp_keepidle = TCPTV_KEEP_IDLE;
  267: 	tcp_keepintvl = TCPTV_KEEPINTVL;
  268: 	tcp_maxpersistidle = TCPTV_KEEP_IDLE;
  269: 	tcp_msl = TCPTV_MSL;
  270: 	tcp_rexmit_min = TCPTV_MIN;
  271: 	tcp_rexmit_slop = TCPTV_CPU_VAR;
  272: 
  273: 	TUNABLE_INT_FETCH("net.inet.tcp.tcbhashsize", &hashsize);
  274: 	if (!powerof2(hashsize)) {
  275: 		printf("WARNING: TCB hash size not a power of 2\n");
  276: 		hashsize = 512; /* safe default */
  277: 	}
  278: 	tcp_tcbhashsize = hashsize;
  279: 	porthashbase = hashinit(hashsize, M_PCB, &porthashmask);
  280: 	wildcardhashbase = hashinit(hashsize, M_PCB, &wildcardhashmask);
  281: 	ipi_zone = zinit("tcpcb", sizeof(struct inp_tp), maxsockets,
  282: 			 ZONE_INTERRUPT, 0);
  283: 
  284: 	for (cpu = 0; cpu < ncpus2; cpu++) {
  285: 		LIST_INIT(&tcbinfo[cpu].listhead);
  286: 		tcbinfo[cpu].hashbase = hashinit(hashsize, M_PCB,
  287: 		    &tcbinfo[cpu].hashmask);
  288: 		tcbinfo[cpu].porthashbase = porthashbase;
  289: 		tcbinfo[cpu].porthashmask = porthashmask;
  290: 		tcbinfo[cpu].wildcardhashbase = wildcardhashbase;
  291: 		tcbinfo[cpu].wildcardhashmask = wildcardhashmask;
  292: 		tcbinfo[cpu].ipi_zone = ipi_zone;
  293: 	}
  294: 
  295: 	tcp_reass_maxseg = nmbclusters / 16;
  296: 	TUNABLE_INT_FETCH("net.inet.tcp.reass.maxsegments",
  297: 	    &tcp_reass_maxseg);
  298: 
  299: #ifdef INET6
  300: #define TCP_MINPROTOHDR (sizeof(struct ip6_hdr) + sizeof(struct tcphdr))
  301: #else /* INET6 */
  302: #define TCP_MINPROTOHDR (sizeof(struct tcpiphdr))
  303: #endif /* INET6 */
  304: 	if (max_protohdr < TCP_MINPROTOHDR)
  305: 		max_protohdr = TCP_MINPROTOHDR;
  306: 	if (max_linkhdr + TCP_MINPROTOHDR > MHLEN)
  307: 		panic("tcp_init");
  308: #undef TCP_MINPROTOHDR
  309: 
  310: 	/*
  311: 	 * Initialize TCP statistics.
  312: 	 *
  313: 	 * It is layed out as an array which is has one element for UP,
  314: 	 * and SMP_MAXCPU elements for SMP.  This allows us to retain
  315: 	 * the access mechanism from userland for both UP and SMP.
  316: 	 */
  317: #ifdef SMP
  318: 	for (cpu = 0; cpu < ncpus; ++cpu) {
  319: 		bzero(&tcpstats_ary[cpu], sizeof(struct tcp_stats));
  320: 	}
  321: #else
  322: 	bzero(&tcpstat, sizeof(struct tcp_stats));
  323: #endif
  324: 
  325: 	syncache_init();
  326: 	tcp_thread_init();
  327: }
  328: 
  329: /*
  330:  * Fill in the IP and TCP headers for an outgoing packet, given the tcpcb.
  331:  * tcp_template used to store this data in mbufs, but we now recopy it out
  332:  * of the tcpcb each time to conserve mbufs.
  333:  */
  334: void
  335: tcp_fillheaders(tp, ip_ptr, tcp_ptr)
  336: 	struct tcpcb *tp;
  337: 	void *ip_ptr;
  338: 	void *tcp_ptr;
  339: {
  340: 	struct inpcb *inp = tp->t_inpcb;
  341: 	struct tcphdr *tcp_hdr = (struct tcphdr *)tcp_ptr;
  342: 
  343: #ifdef INET6
  344: 	if ((inp->inp_vflag & INP_IPV6) != 0) {
  345: 		struct ip6_hdr *ip6;
  346: 
  347: 		ip6 = (struct ip6_hdr *)ip_ptr;
  348: 		ip6->ip6_flow = (ip6->ip6_flow & ~IPV6_FLOWINFO_MASK) |
  349: 			(inp->in6p_flowinfo & IPV6_FLOWINFO_MASK);
  350: 		ip6->ip6_vfc = (ip6->ip6_vfc & ~IPV6_VERSION_MASK) |
  351: 			(IPV6_VERSION & IPV6_VERSION_MASK);
  352: 		ip6->ip6_nxt = IPPROTO_TCP;
  353: 		ip6->ip6_plen = sizeof(struct tcphdr);
  354: 		ip6->ip6_src = inp->in6p_laddr;
  355: 		ip6->ip6_dst = inp->in6p_faddr;
  356: 		tcp_hdr->th_sum = 0;
  357: 	} else
  358: #endif
  359: 	{
  360: 	struct ip *ip = (struct ip *) ip_ptr;
  361: 
  362: 	ip->ip_vhl = IP_VHL_BORING;
  363: 	ip->ip_tos = 0;
  364: 	ip->ip_len = 0;
  365: 	ip->ip_id = 0;
  366: 	ip->ip_off = 0;
  367: 	ip->ip_ttl = 0;
  368: 	ip->ip_sum = 0;
  369: 	ip->ip_p = IPPROTO_TCP;
  370: 	ip->ip_src = inp->inp_laddr;
  371: 	ip->ip_dst = inp->inp_faddr;
  372: 	tcp_hdr->th_sum = in_pseudo(ip->ip_src.s_addr, ip->ip_dst.s_addr,
  373: 		htons(sizeof(struct tcphdr) + IPPROTO_TCP));
  374: 	}
  375: 
  376: 	tcp_hdr->th_sport = inp->inp_lport;
  377: 	tcp_hdr->th_dport = inp->inp_fport;
  378: 	tcp_hdr->th_seq = 0;
  379: 	tcp_hdr->th_ack = 0;
  380: 	tcp_hdr->th_x2 = 0;
  381: 	tcp_hdr->th_off = 5;
  382: 	tcp_hdr->th_flags = 0;
  383: 	tcp_hdr->th_win = 0;
  384: 	tcp_hdr->th_urp = 0;
  385: }
  386: 
  387: /*
  388:  * Create template to be used to send tcp packets on a connection.
  389:  * Allocates an mbuf and fills in a skeletal tcp/ip header.  The only
  390:  * use for this function is in keepalives, which use tcp_respond.
  391:  */
  392: struct tcptemp *
  393: tcp_maketemplate(tp)
  394: 	struct tcpcb *tp;
  395: {
  396: 	struct mbuf *m;
  397: 	struct tcptemp *n;
  398: 
  399: 	m = m_get(M_DONTWAIT, MT_HEADER);
  400: 	if (m == NULL)
  401: 		return (0);
  402: 	m->m_len = sizeof(struct tcptemp);
  403: 	n = mtod(m, struct tcptemp *);
  404: 
  405: 	tcp_fillheaders(tp, (void *)&n->tt_ipgen, (void *)&n->tt_t);
  406: 	return (n);
  407: }
  408: 
  409: /*
  410:  * Send a single message to the TCP at address specified by
  411:  * the given TCP/IP header.  If m == 0, then we make a copy
  412:  * of the tcpiphdr at ti and send directly to the addressed host.
  413:  * This is used to force keep alive messages out using the TCP
  414:  * template for a connection.  If flags are given then we send
  415:  * a message back to the TCP which originated the * segment ti,
  416:  * and discard the mbuf containing it and any other attached mbufs.
  417:  *
  418:  * In any case the ack and sequence number of the transmitted
  419:  * segment are as specified by the parameters.
  420:  *
  421:  * NOTE: If m != NULL, then ti must point to *inside* the mbuf.
  422:  */
  423: void
  424: tcp_respond(tp, ipgen, th, m, ack, seq, flags)
  425: 	struct tcpcb *tp;
  426: 	void *ipgen;
  427: 	struct tcphdr *th;
  428: 	struct mbuf *m;
  429: 	tcp_seq ack, seq;
  430: 	int flags;
  431: {
  432: 	int tlen;
  433: 	int win = 0;
  434: 	struct route *ro = 0;
  435: 	struct route sro;
  436: 	struct ip *ip;
  437: 	struct tcphdr *nth;
  438: #ifdef INET6
  439: 	struct route_in6 *ro6 = 0;
  440: 	struct route_in6 sro6;
  441: 	struct ip6_hdr *ip6;
  442: 	int isipv6;
  443: #endif /* INET6 */
  444: 	int ipflags = 0;
  445: 
  446: #ifdef INET6
  447: 	isipv6 = IP_VHL_V(((struct ip *)ipgen)->ip_vhl) == 6;
  448: 	ip6 = ipgen;
  449: #endif /* INET6 */
  450: 	ip = ipgen;
  451: 
  452: 	if (tp) {
  453: 		if (!(flags & TH_RST)) {
  454: 			win = sbspace(&tp->t_inpcb->inp_socket->so_rcv);
  455: 			if (win > (long)TCP_MAXWIN << tp->rcv_scale)
  456: 				win = (long)TCP_MAXWIN << tp->rcv_scale;
  457: 		}
  458: #ifdef INET6
  459: 		if (isipv6)
  460: 			ro6 = &tp->t_inpcb->in6p_route;
  461: 		else
  462: #endif /* INET6 */
  463: 		ro = &tp->t_inpcb->inp_route;
  464: 	} else {
  465: #ifdef INET6
  466: 		if (isipv6) {
  467: 			ro6 = &sro6;
  468: 			bzero(ro6, sizeof *ro6);
  469: 		} else
  470: #endif /* INET6 */
  471: 	      {
  472: 		ro = &sro;
  473: 		bzero(ro, sizeof *ro);
  474: 	      }
  475: 	}
  476: 	if (m == 0) {
  477: 		m = m_gethdr(M_DONTWAIT, MT_HEADER);
  478: 		if (m == NULL)
  479: 			return;
  480: 		tlen = 0;
  481: 		m->m_data += max_linkhdr;
  482: #ifdef INET6
  483: 		if (isipv6) {
  484: 			bcopy((caddr_t)ip6, mtod(m, caddr_t), 
  485: 			      sizeof(struct ip6_hdr));
  486: 			ip6 = mtod(m, struct ip6_hdr *);
  487: 			nth = (struct tcphdr *)(ip6 + 1);
  488: 		} else
  489: #endif /* INET6 */
  490: 	      {
  491: 		bcopy((caddr_t)ip, mtod(m, caddr_t), sizeof(struct ip));
  492: 		ip = mtod(m, struct ip *);
  493: 		nth = (struct tcphdr *)(ip + 1);
  494: 	      }
  495: 		bcopy((caddr_t)th, (caddr_t)nth, sizeof(struct tcphdr));
  496: 		flags = TH_ACK;
  497: 	} else {
  498: 		m_freem(m->m_next);
  499: 		m->m_next = 0;
  500: 		m->m_data = (caddr_t)ipgen;
  501: 		/* m_len is set later */
  502: 		tlen = 0;
  503: #define xchg(a,b,type) { type t; t=a; a=b; b=t; }
  504: #ifdef INET6
  505: 		if (isipv6) {
  506: 			xchg(ip6->ip6_dst, ip6->ip6_src, struct in6_addr);
  507: 			nth = (struct tcphdr *)(ip6 + 1);
  508: 		} else
  509: #endif /* INET6 */
  510: 	      {
  511: 		xchg(ip->ip_dst.s_addr, ip->ip_src.s_addr, n_long);
  512: 		nth = (struct tcphdr *)(ip + 1);
  513: 	      }
  514: 		if (th != nth) {
  515: 			/*
  516: 			 * this is usually a case when an extension header
  517: 			 * exists between the IPv6 header and the
  518: 			 * TCP header.
  519: 			 */
  520: 			nth->th_sport = th->th_sport;
  521: 			nth->th_dport = th->th_dport;
  522: 		}
  523: 		xchg(nth->th_dport, nth->th_sport, n_short);
  524: #undef xchg
  525: 	}
  526: #ifdef INET6
  527: 	if (isipv6) {
  528: 		ip6->ip6_flow = 0;
  529: 		ip6->ip6_vfc = IPV6_VERSION;
  530: 		ip6->ip6_nxt = IPPROTO_TCP;
  531: 		ip6->ip6_plen = htons((u_short)(sizeof (struct tcphdr) +
  532: 						tlen));
  533: 		tlen += sizeof (struct ip6_hdr) + sizeof (struct tcphdr);
  534: 	} else
  535: #endif
  536:       {
  537: 	tlen += sizeof (struct tcpiphdr);
  538: 	ip->ip_len = tlen;
  539: 	ip->ip_ttl = ip_defttl;
  540:       }
  541: 	m->m_len = tlen;
  542: 	m->m_pkthdr.len = tlen;
  543: 	m->m_pkthdr.rcvif = (struct ifnet *) 0;
  544: 	nth->th_seq = htonl(seq);
  545: 	nth->th_ack = htonl(ack);
  546: 	nth->th_x2 = 0;
  547: 	nth->th_off = sizeof (struct tcphdr) >> 2;
  548: 	nth->th_flags = flags;
  549: 	if (tp)
  550: 		nth->th_win = htons((u_short) (win >> tp->rcv_scale));
  551: 	else
  552: 		nth->th_win = htons((u_short)win);
  553: 	nth->th_urp = 0;
  554: #ifdef INET6
  555: 	if (isipv6) {
  556: 		nth->th_sum = 0;
  557: 		nth->th_sum = in6_cksum(m, IPPROTO_TCP,
  558: 					sizeof(struct ip6_hdr),
  559: 					tlen - sizeof(struct ip6_hdr));
  560: 		ip6->ip6_hlim = in6_selecthlim(tp ? tp->t_inpcb : NULL,
  561: 					       ro6 && ro6->ro_rt ?
  562: 					       ro6->ro_rt->rt_ifp :
  563: 					       NULL);
  564: 	} else
  565: #endif /* INET6 */
  566:       {
  567:         nth->th_sum = in_pseudo(ip->ip_src.s_addr, ip->ip_dst.s_addr,
  568: 	    htons((u_short)(tlen - sizeof(struct ip) + ip->ip_p)));
  569:         m->m_pkthdr.csum_flags = CSUM_TCP;
  570:         m->m_pkthdr.csum_data = offsetof(struct tcphdr, th_sum);
  571:       }
  572: #ifdef TCPDEBUG
  573: 	if (tp == NULL || (tp->t_inpcb->inp_socket->so_options & SO_DEBUG))
  574: 		tcp_trace(TA_OUTPUT, 0, tp, mtod(m, void *), th, 0);
  575: #endif
  576: #ifdef INET6
  577: 	if (isipv6) {
  578: 		(void)ip6_output(m, NULL, ro6, ipflags, NULL, NULL,
  579: 			tp ? tp->t_inpcb : NULL);
  580: 		if (ro6 == &sro6 && ro6->ro_rt) {
  581: 			RTFREE(ro6->ro_rt);
  582: 			ro6->ro_rt = NULL;
  583: 		}
  584: 	} else
  585: #endif /* INET6 */
  586:       {
  587: 	(void) ip_output(m, NULL, ro, ipflags, NULL, tp ? tp->t_inpcb : NULL);
  588: 	if (ro == &sro && ro->ro_rt) {
  589: 		RTFREE(ro->ro_rt);
  590: 		ro->ro_rt = NULL;
  591: 	}
  592:       }
  593: }
  594: 
  595: /*
  596:  * Create a new TCP control block, making an
  597:  * empty reassembly queue and hooking it to the argument
  598:  * protocol control block.  The `inp' parameter must have
  599:  * come from the zone allocator set up in tcp_init().
  600:  */
  601: struct tcpcb *
  602: tcp_newtcpcb(inp)
  603: 	struct inpcb *inp;
  604: {
  605: 	struct inp_tp *it;
  606: 	struct tcpcb *tp;
  607: #ifdef INET6
  608: 	int isipv6 = (inp->inp_vflag & INP_IPV6) != 0;
  609: #endif /* INET6 */
  610: 
  611: 	it = (struct inp_tp *)inp;
  612: 	tp = &it->tcb;
  613: 	bzero((char *) tp, sizeof(struct tcpcb));
  614: 	LIST_INIT(&tp->t_segq);
  615: 	tp->t_maxseg = tp->t_maxopd =
  616: #ifdef INET6
  617: 		isipv6 ? tcp_v6mssdflt :
  618: #endif /* INET6 */
  619: 		tcp_mssdflt;
  620: 
  621: 	/* Set up our timeouts. */
  622: 	callout_init(tp->tt_rexmt = &it->inp_tp_rexmt);
  623: 	callout_init(tp->tt_persist = &it->inp_tp_persist);
  624: 	callout_init(tp->tt_keep = &it->inp_tp_keep);
  625: 	callout_init(tp->tt_2msl = &it->inp_tp_2msl);
  626: 	callout_init(tp->tt_delack = &it->inp_tp_delack);
  627: 
  628: 	if (tcp_do_rfc1323)
  629: 		tp->t_flags = (TF_REQ_SCALE|TF_REQ_TSTMP);
  630: 	if (tcp_do_rfc1644)
  631: 		tp->t_flags |= TF_REQ_CC;
  632: 	tp->t_inpcb = inp;	/* XXX */
  633: 	/*
  634: 	 * Init srtt to TCPTV_SRTTBASE (0), so we can tell that we have no
  635: 	 * rtt estimate.  Set rttvar so that srtt + 4 * rttvar gives
  636: 	 * reasonable initial retransmit time.
  637: 	 */
  638: 	tp->t_srtt = TCPTV_SRTTBASE;
  639: 	tp->t_rttvar = ((TCPTV_RTOBASE - TCPTV_SRTTBASE) << TCP_RTTVAR_SHIFT) / 4;
  640: 	tp->t_rttmin = tcp_rexmit_min;
  641: 	tp->t_rxtcur = TCPTV_RTOBASE;
  642: 	tp->snd_cwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT;
  643: 	tp->snd_bwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT;
  644: 	tp->snd_ssthresh = TCP_MAXWIN << TCP_MAX_WINSHIFT;
  645: 	tp->t_rcvtime = ticks;
  646: 	tp->t_bw_rtttime = ticks;
  647:         /*
  648: 	 * IPv4 TTL initialization is necessary for an IPv6 socket as well,
  649: 	 * because the socket may be bound to an IPv6 wildcard address,
  650: 	 * which may match an IPv4-mapped IPv6 address.
  651: 	 */
  652: 	inp->inp_ip_ttl = ip_defttl;
  653: 	inp->inp_ppcb = (caddr_t)tp;
  654: 	return (tp);		/* XXX */
  655: }
  656: 
  657: /*
  658:  * Drop a TCP connection, reporting
  659:  * the specified error.  If connection is synchronized,
  660:  * then send a RST to peer.
  661:  */
  662: struct tcpcb *
  663: tcp_drop(tp, errno)
  664: 	struct tcpcb *tp;
  665: 	int errno;
  666: {
  667: 	struct socket *so = tp->t_inpcb->inp_socket;
  668: 
  669: 	if (TCPS_HAVERCVDSYN(tp->t_state)) {
  670: 		tp->t_state = TCPS_CLOSED;
  671: 		(void) tcp_output(tp);
  672: 		tcpstat.tcps_drops++;
  673: 	} else
  674: 		tcpstat.tcps_conndrops++;
  675: 	if (errno == ETIMEDOUT && tp->t_softerror)
  676: 		errno = tp->t_softerror;
  677: 	so->so_error = errno;
  678: 	return (tcp_close(tp));
  679: }
  680: 
  681: /*
  682:  * Close a TCP control block:
  683:  *	discard all space held by the tcp
  684:  *	discard internet protocol block
  685:  *	wake up any sleepers
  686:  */
  687: struct tcpcb *
  688: tcp_close(tp)
  689: 	struct tcpcb *tp;
  690: {
  691: 	struct tseg_qent *q;
  692: 	struct inpcb *inp = tp->t_inpcb;
  693: 	struct socket *so = inp->inp_socket;
  694: #ifdef INET6
  695: 	int isipv6 = (inp->inp_vflag & INP_IPV6) != 0;
  696: #endif /* INET6 */
  697: 	struct rtentry *rt;
  698: 	int dosavessthresh;
  699: 
  700: 	/*
  701: 	 * Make sure that all of our timers are stopped before we
  702: 	 * delete the PCB.
  703: 	 */
  704: 	callout_stop(tp->tt_rexmt);
  705: 	callout_stop(tp->tt_persist);
  706: 	callout_stop(tp->tt_keep);
  707: 	callout_stop(tp->tt_2msl);
  708: 	callout_stop(tp->tt_delack);
  709: 
  710: 	/*
  711: 	 * If we got enough samples through the srtt filter,
  712: 	 * save the rtt and rttvar in the routing entry.
  713: 	 * 'Enough' is arbitrarily defined as the 16 samples.
  714: 	 * 16 samples is enough for the srtt filter to converge
  715: 	 * to within 5% of the correct value; fewer samples and
  716: 	 * we could save a very bogus rtt.
  717: 	 *
  718: 	 * Don't update the default route's characteristics and don't
  719: 	 * update anything that the user "locked".
  720: 	 */
  721: 	if (tp->t_rttupdated >= 16) {
  722: 		u_long i = 0;
  723: #ifdef INET6
  724: 		if (isipv6) {
  725: 			struct sockaddr_in6 *sin6;
  726: 
  727: 			if ((rt = inp->in6p_route.ro_rt) == NULL)
  728: 				goto no_valid_rt;
  729: 			sin6 = (struct sockaddr_in6 *)rt_key(rt);
  730: 			if (IN6_IS_ADDR_UNSPECIFIED(&sin6->sin6_addr))
  731: 				goto no_valid_rt;
  732: 		}
  733: 		else
  734: #endif /* INET6 */		
  735: 		if ((rt = inp->inp_route.ro_rt) == NULL ||
  736: 		    ((struct sockaddr_in *)rt_key(rt))->sin_addr.s_addr
  737: 		    == INADDR_ANY)
  738: 			goto no_valid_rt;
  739: 
  740: 		if ((rt->rt_rmx.rmx_locks & RTV_RTT) == 0) {
  741: 			i = tp->t_srtt *
  742: 			    (RTM_RTTUNIT / (hz * TCP_RTT_SCALE));
  743: 			if (rt->rt_rmx.rmx_rtt && i)
  744: 				/*
  745: 				 * filter this update to half the old & half
  746: 				 * the new values, converting scale.
  747: 				 * See route.h and tcp_var.h for a
  748: 				 * description of the scaling constants.
  749: 				 */
  750: 				rt->rt_rmx.rmx_rtt =
  751: 				    (rt->rt_rmx.rmx_rtt + i) / 2;
  752: 			else
  753: 				rt->rt_rmx.rmx_rtt = i;
  754: 			tcpstat.tcps_cachedrtt++;
  755: 		}
  756: 		if ((rt->rt_rmx.rmx_locks & RTV_RTTVAR) == 0) {
  757: 			i = tp->t_rttvar *
  758: 			    (RTM_RTTUNIT / (hz * TCP_RTTVAR_SCALE));
  759: 			if (rt->rt_rmx.rmx_rttvar && i)
  760: 				rt->rt_rmx.rmx_rttvar =
  761: 				    (rt->rt_rmx.rmx_rttvar + i) / 2;
  762: 			else
  763: 				rt->rt_rmx.rmx_rttvar = i;
  764: 			tcpstat.tcps_cachedrttvar++;
  765: 		}
  766: 		/*
  767: 		 * The old comment here said:
  768: 		 * update the pipelimit (ssthresh) if it has been updated
  769: 		 * already or if a pipesize was specified & the threshhold
  770: 		 * got below half the pipesize.  I.e., wait for bad news
  771: 		 * before we start updating, then update on both good
  772: 		 * and bad news.
  773: 		 *
  774: 		 * But we want to save the ssthresh even if no pipesize is
  775: 		 * specified explicitly in the route, because such
  776: 		 * connections still have an implicit pipesize specified
  777: 		 * by the global tcp_sendspace.  In the absence of a reliable
  778: 		 * way to calculate the pipesize, it will have to do.
  779: 		 */
  780: 		i = tp->snd_ssthresh;
  781: 		if (rt->rt_rmx.rmx_sendpipe != 0)
  782: 			dosavessthresh = (i < rt->rt_rmx.rmx_sendpipe / 2);
  783: 		else
  784: 			dosavessthresh = (i < so->so_snd.sb_hiwat / 2);
  785: 		if (((rt->rt_rmx.rmx_locks & RTV_SSTHRESH) == 0 &&
  786: 		     i != 0 && rt->rt_rmx.rmx_ssthresh != 0)
  787: 		    || dosavessthresh) {
  788: 			/*
  789: 			 * convert the limit from user data bytes to
  790: 			 * packets then to packet data bytes.
  791: 			 */
  792: 			i = (i + tp->t_maxseg / 2) / tp->t_maxseg;
  793: 			if (i < 2)
  794: 				i = 2;
  795: 			i *= (u_long)(tp->t_maxseg +
  796: #ifdef INET6
  797: 				      (isipv6 ? sizeof (struct ip6_hdr) +
  798: 					       sizeof (struct tcphdr) :
  799: #endif
  800: 				       sizeof (struct tcpiphdr)
  801: #ifdef INET6
  802: 				       )
  803: #endif
  804: 				      );
  805: 			if (rt->rt_rmx.rmx_ssthresh)
  806: 				rt->rt_rmx.rmx_ssthresh =
  807: 				    (rt->rt_rmx.rmx_ssthresh + i) / 2;
  808: 			else
  809: 				rt->rt_rmx.rmx_ssthresh = i;
  810: 			tcpstat.tcps_cachedssthresh++;
  811: 		}
  812: 	}
  813:     no_valid_rt:
  814: 	/* free the reassembly queue, if any */
  815: 	while((q = LIST_FIRST(&tp->t_segq)) != NULL) {
  816: 		LIST_REMOVE(q, tqe_q);
  817: 		m_freem(q->tqe_m);
  818: 		FREE(q, M_TSEGQ);
  819: 		tcp_reass_qsize--;
  820: 	}
  821: 	inp->inp_ppcb = NULL;
  822: 	soisdisconnected(so);
  823: #ifdef INET6
  824: 	if (INP_CHECK_SOCKAF(so, AF_INET6))
  825: 		in6_pcbdetach(inp);
  826: 	else
  827: #endif /* INET6 */
  828: 	in_pcbdetach(inp);
  829: 	tcpstat.tcps_closed++;
  830: 	return ((struct tcpcb *)0);
  831: }
  832: 
  833: static __inline void
  834: tcp_drain_oncpu(struct inpcbhead *head)
  835: {
  836: 	struct inpcb *inpb;
  837: 	struct tcpcb *tcpb;
  838: 	struct tseg_qent *te;
  839: 
  840: 	LIST_FOREACH(inpb, head, inp_list) {
  841: 		if ((tcpb = intotcpcb(inpb))) {
  842: 			while ((te = LIST_FIRST(&tcpb->t_segq)) != NULL) {
  843: 				LIST_REMOVE(te, tqe_q);
  844: 				m_freem(te->tqe_m);
  845: 				FREE(te, M_TSEGQ);
  846: 				tcp_reass_qsize--;
  847: 			}
  848: 		}
  849: 	}
  850: }
  851: 
  852: #ifdef SMP
  853: struct netmsg_tcp_drain {
  854: 	struct lwkt_msg		nm_lmsg;
  855: 	netisr_fn_t		nm_handler;
  856: 	struct inpcbhead	*nm_head;
  857: };
  858: 
  859: static void
  860: tcp_drain_handler(struct netmsg *msg0)
  861: {
  862: 	struct netmsg_tcp_drain *nm = (struct netmsg_tcp_drain *)msg0;
  863: 
  864: 	tcp_drain_oncpu(nm->nm_head);
  865: 	lwkt_replymsg(&msg0->nm_lmsg, 0);
  866: }
  867: #endif
  868: 
  869: void
  870: tcp_drain()
  871: {
  872: #ifdef SMP
  873: 	int cpu;
  874: #endif
  875: 
  876: 	if (!do_tcpdrain)
  877: 		return;
  878: 
  879: 	/*
  880: 	 * Walk the tcpbs, if existing, and flush the reassembly queue,
  881: 	 * if there is one...
  882: 	 * XXX: The "Net/3" implementation doesn't imply that the TCP
  883: 	 *      reassembly queue should be flushed, but in a situation
  884: 	 * 	where we're really low on mbufs, this is potentially
  885: 	 *  	usefull.	
  886: 	 */
  887: #ifdef SMP
  888: 	for (cpu = 0; cpu < ncpus2; cpu++) {
  889: 		struct netmsg_tcp_drain *msg;
  890: 
  891: 		if (cpu == mycpu->gd_cpuid) {
  892: 			tcp_drain_oncpu(&tcbinfo[cpu].listhead);
  893: 		} else {
  894: 			msg = malloc(sizeof(struct netmsg_tcp_drain),
  895: 			    M_LWKTMSG, M_NOWAIT);
  896: 			if (!msg)
  897: 				continue;
  898: 			lwkt_initmsg_rp(&msg->nm_lmsg, &netisr_afree_rport,
  899: 			    CMD_NETMSG_ONCPU);
  900: 			msg->nm_handler = tcp_drain_handler;
  901: 			msg->nm_head = &tcbinfo[cpu].listhead;
  902: 			lwkt_sendmsg(tcp_cport(cpu), &msg->nm_lmsg);
  903: 		}
  904: 	}
  905: #else
  906: 	tcp_drain_oncpu(&tcbinfo[0].listhead);
  907: #endif
  908: }
  909: 
  910: /*
  911:  * Notify a tcp user of an asynchronous error;
  912:  * store error as soft error, but wake up user
  913:  * (for now, won't do anything until can select for soft error).
  914:  *
  915:  * Do not wake up user since there currently is no mechanism for
  916:  * reporting soft errors (yet - a kqueue filter may be added).
  917:  */
  918: static void
  919: tcp_notify(inp, error)
  920: 	struct inpcb *inp;
  921: 	int error;
  922: {
  923: 	struct tcpcb *tp = (struct tcpcb *)inp->inp_ppcb;
  924: 
  925: 	/*
  926: 	 * Ignore some errors if we are hooked up.
  927: 	 * If connection hasn't completed, has retransmitted several times,
  928: 	 * and receives a second error, give up now.  This is better
  929: 	 * than waiting a long time to establish a connection that
  930: 	 * can never complete.
  931: 	 */
  932: 	if (tp->t_state == TCPS_ESTABLISHED &&
  933: 	     (error == EHOSTUNREACH || error == ENETUNREACH ||
  934: 	      error == EHOSTDOWN)) {
  935: 		return;
  936: 	} else if (tp->t_state < TCPS_ESTABLISHED && tp->t_rxtshift > 3 &&
  937: 	    tp->t_softerror)
  938: 		tcp_drop(tp, error);
  939: 	else
  940: 		tp->t_softerror = error;
  941: #if 0
  942: 	wakeup((caddr_t) &so->so_timeo);
  943: 	sorwakeup(so);
  944: 	sowwakeup(so);
  945: #endif
  946: }
  947: 
  948: static int
  949: tcp_pcblist(SYSCTL_HANDLER_ARGS)
  950: {
  951: 	int error, i, n, s;
  952: 	struct inpcb *inp, **inp_list;
  953: 	inp_gen_t gencnt;
  954: 	struct xinpgen xig;
  955: 
  956: 	/*
  957: 	 * The process of preparing the TCB list is too time-consuming and
  958: 	 * resource-intensive to repeat twice on every request.
  959: 	 */
  960: 	if (req->oldptr == 0) {
  961: 		n = tcbinfo[mycpu->gd_cpuid].ipi_count;
  962: 		req->oldidx = 2 * (sizeof xig)
  963: 			+ (n + n/8) * sizeof(struct xtcpcb);
  964: 		return 0;
  965: 	}
  966: 
  967: 	if (req->newptr != 0)
  968: 		return EPERM;
  969: 
  970: 	/*
  971: 	 * OK, now we're committed to doing something.
  972: 	 */
  973: 	s = splnet();
  974: 	gencnt = tcbinfo[mycpu->gd_cpuid].ipi_gencnt;
  975: 	n = tcbinfo[mycpu->gd_cpuid].ipi_count;
  976: 	splx(s);
  977: 
  978: 	xig.xig_len = sizeof xig;
  979: 	xig.xig_count = n;
  980: 	xig.xig_gen = gencnt;
  981: 	xig.xig_sogen = so_gencnt;
  982: 	error = SYSCTL_OUT(req, &xig, sizeof xig);
  983: 	if (error)
  984: 		return error;
  985: 
  986: 	inp_list = malloc(n * sizeof *inp_list, M_TEMP, M_WAITOK);
  987: 	if (inp_list == 0)
  988: 		return ENOMEM;
  989: 	
  990: 	s = splnet();
  991: 	for (inp = LIST_FIRST(&tcbinfo[mycpu->gd_cpuid].listhead), i = 0;
  992: 	    inp && i < n; inp = LIST_NEXT(inp, inp_list)) {
  993: 		if (inp->inp_gencnt <= gencnt && !prison_xinpcb(req->td, inp))
  994: 			inp_list[i++] = inp;
  995: 	}
  996: 	splx(s);
  997: 	n = i;
  998: 
  999: 	error = 0;
 1000: 	for (i = 0; i < n; i++) {
 1001: 		inp = inp_list[i];
 1002: 		if (inp->inp_gencnt <= gencnt) {
 1003: 			struct xtcpcb xt;
 1004: 			caddr_t inp_ppcb;
 1005: 			xt.xt_len = sizeof xt;
 1006: 			/* XXX should avoid extra copy */
 1007: 			bcopy(inp, &xt.xt_inp, sizeof *inp);
 1008: 			inp_ppcb = inp->inp_ppcb;
 1009: 			if (inp_ppcb != NULL)
 1010: 				bcopy(inp_ppcb, &xt.xt_tp, sizeof xt.xt_tp);
 1011: 			else
 1012: 				bzero((char *) &xt.xt_tp, sizeof xt.xt_tp);
 1013: 			if (inp->inp_socket)
 1014: 				sotoxsocket(inp->inp_socket, &xt.xt_socket);
 1015: 			error = SYSCTL_OUT(req, &xt, sizeof xt);
 1016: 		}
 1017: 	}
 1018: 	if (!error) {
 1019: 		/*
 1020: 		 * Give the user an updated idea of our state.
 1021: 		 * If the generation differs from what we told
 1022: 		 * her before, she knows that something happened
 1023: 		 * while we were processing this request, and it
 1024: 		 * might be necessary to retry.
 1025: 		 */
 1026: 		s = splnet();
 1027: 		xig.xig_gen = tcbinfo[mycpu->gd_cpuid].ipi_gencnt;
 1028: 		xig.xig_sogen = so_gencnt;
 1029: 		xig.xig_count = tcbinfo[mycpu->gd_cpuid].ipi_count;
 1030: 		splx(s);
 1031: 		error = SYSCTL_OUT(req, &xig, sizeof xig);
 1032: 	}
 1033: 	free(inp_list, M_TEMP);
 1034: 	return error;
 1035: }
 1036: 
 1037: SYSCTL_PROC(_net_inet_tcp, TCPCTL_PCBLIST, pcblist, CTLFLAG_RD, 0, 0,
 1038: 	    tcp_pcblist, "S,xtcpcb", "List of active TCP connections");
 1039: 
 1040: static int
 1041: tcp_getcred(SYSCTL_HANDLER_ARGS)
 1042: {
 1043: 	struct sockaddr_in addrs[2];
 1044: 	struct inpcb *inp;
 1045: 	int cpu;
 1046: 	int error, s;
 1047: 
 1048: 	error = suser(req->td);
 1049: 	if (error)
 1050: 		return (error);
 1051: 	error = SYSCTL_IN(req, addrs, sizeof(addrs));
 1052: 	if (error)
 1053: 		return (error);
 1054: 	s = splnet();
 1055: 
 1056: #ifdef TCP_DISTRIBUTED_TCBINFO
 1057: 	cpu = tcp_addrcpu(addrs[1].sin_addr.s_addr, addrs[1].sin_port,
 1058: 	    addrs[0].sin_addr.s_addr, addrs[0].sin_port);
 1059: #else
 1060: 	cpu = 0;
 1061: #endif
 1062: 	inp = in_pcblookup_hash(&tcbinfo[cpu], addrs[1].sin_addr,
 1063: 	    addrs[1].sin_port, addrs[0].sin_addr, addrs[0].sin_port, 0, NULL);
 1064: 	if (inp == NULL || inp->inp_socket == NULL) {
 1065: 		error = ENOENT;
 1066: 		goto out;
 1067: 	}
 1068: 	error = SYSCTL_OUT(req, inp->inp_socket->so_cred, sizeof(struct ucred));
 1069: out:
 1070: 	splx(s);
 1071: 	return (error);
 1072: }
 1073: 
 1074: SYSCTL_PROC(_net_inet_tcp, OID_AUTO, getcred, CTLTYPE_OPAQUE|CTLFLAG_RW,
 1075:     0, 0, tcp_getcred, "S,ucred", "Get the ucred of a TCP connection");
 1076: 
 1077: #ifdef INET6
 1078: static int
 1079: tcp6_getcred(SYSCTL_HANDLER_ARGS)
 1080: {
 1081: 	struct sockaddr_in6 addrs[2];
 1082: 	struct inpcb *inp;
 1083: 	int error, s, mapped = 0;
 1084: 
 1085: 	error = suser(req->td);
 1086: 	if (error)
 1087: 		return (error);
 1088: 	error = SYSCTL_IN(req, addrs, sizeof(addrs));
 1089: 	if (error)
 1090: 		return (error);
 1091: 	if (IN6_IS_ADDR_V4MAPPED(&addrs[0].sin6_addr)) {
 1092: 		if (IN6_IS_ADDR_V4MAPPED(&addrs[1].sin6_addr))
 1093: 			mapped = 1;
 1094: 		else
 1095: 			return (EINVAL);
 1096: 	}
 1097: 	s = splnet();
 1098: 	if (mapped == 1) {
 1099: 		inp = in_pcblookup_hash(&tcbinfo[0],
 1100: 		    *(struct in_addr *)&addrs[1].sin6_addr.s6_addr[12],
 1101: 		    addrs[1].sin6_port,
 1102: 		    *(struct in_addr *)&addrs[0].sin6_addr.s6_addr[12],
 1103: 		    addrs[0].sin6_port,
 1104: 		    0, NULL);
 1105: 	} else {
 1106: 		inp = in6_pcblookup_hash(&tcbinfo[0],
 1107: 		    &addrs[1].sin6_addr, addrs[1].sin6_port,
 1108: 		    &addrs[0].sin6_addr, addrs[0].sin6_port,
 1109: 		    0, NULL);
 1110: 	}
 1111: 	if (inp == NULL || inp->inp_socket == NULL) {
 1112: 		error = ENOENT;
 1113: 		goto out;
 1114: 	}
 1115: 	error = SYSCTL_OUT(req, inp->inp_socket->so_cred, 
 1116: 			   sizeof(struct ucred));
 1117: out:
 1118: 	splx(s);
 1119: 	return (error);
 1120: }
 1121: 
 1122: SYSCTL_PROC(_net_inet6_tcp6, OID_AUTO, getcred, CTLTYPE_OPAQUE|CTLFLAG_RW,
 1123: 	    0, 0,
 1124: 	    tcp6_getcred, "S,ucred", "Get the ucred of a TCP6 connection");
 1125: #endif
 1126: 
 1127: 
 1128: void
 1129: tcp_ctlinput(cmd, sa, vip)
 1130: 	int cmd;
 1131: 	struct sockaddr *sa;
 1132: 	void *vip;
 1133: {
 1134: 	struct ip *ip = vip;
 1135: 	struct tcphdr *th;
 1136: 	struct in_addr faddr;
 1137: 	struct inpcb *inp;
 1138: 	struct tcpcb *tp;
 1139: 	void (*notify) (struct inpcb *, int) = tcp_notify;
 1140: 	tcp_seq icmp_seq;
 1141: 	int cpu;
 1142: 	int s;
 1143: 
 1144: 	faddr = ((struct sockaddr_in *)sa)->sin_addr;
 1145: 	if (sa->sa_family != AF_INET || faddr.s_addr == INADDR_ANY)
 1146: 		return;
 1147: 
 1148: 	if (cmd == PRC_QUENCH)
 1149: 		notify = tcp_quench;
 1150: 	else if (icmp_may_rst && (cmd == PRC_UNREACH_ADMIN_PROHIB ||
 1151: 		cmd == PRC_UNREACH_PORT || cmd == PRC_TIMXCEED_INTRANS) && ip)
 1152: 		notify = tcp_drop_syn_sent;
 1153: 	else if (cmd == PRC_MSGSIZE)
 1154: 		notify = tcp_mtudisc;
 1155: 	else if (PRC_IS_REDIRECT(cmd)) {
 1156: 		ip = 0;
 1157: 		notify = in_rtchange;
 1158: 	} else if (cmd == PRC_HOSTDEAD)
 1159: 		ip = 0;
 1160: 	else if ((unsigned)cmd > PRC_NCMDS || inetctlerrmap[cmd] == 0)
 1161: 		return;
 1162: 	if (ip) {
 1163: 		s = splnet();
 1164: 		th = (struct tcphdr *)((caddr_t)ip 
 1165: 				       + (IP_VHL_HL(ip->ip_vhl) << 2));
 1166: #ifdef TCP_DISTRIBUTED_TCBINFO
 1167: 		cpu = tcp_addrcpu(faddr.s_addr, th->th_dport,
 1168: 		    ip->ip_src.s_addr, th->th_sport);
 1169: #else
 1170: 		cpu = 0;
 1171: #endif
 1172: 		inp = in_pcblookup_hash(&tcbinfo[cpu], faddr, th->th_dport,
 1173: 		    ip->ip_src, th->th_sport, 0, NULL);
 1174: 		if (inp != NULL && inp->inp_socket != NULL) {
 1175: 			icmp_seq = htonl(th->th_seq);
 1176: 			tp = intotcpcb(inp);
 1177: 			if (SEQ_GEQ(icmp_seq, tp->snd_una) &&
 1178: 			    SEQ_LT(icmp_seq, tp->snd_max))
 1179: 				(*notify)(inp, inetctlerrmap[cmd]);
 1180: 		} else {
 1181: 			struct in_conninfo inc;
 1182: 
 1183: 			inc.inc_fport = th->th_dport;
 1184: 			inc.inc_lport = th->th_sport;
 1185: 			inc.inc_faddr = faddr;
 1186: 			inc.inc_laddr = ip->ip_src;
 1187: #ifdef INET6
 1188: 			inc.inc_isipv6 = 0;
 1189: #endif
 1190: 			syncache_unreach(&inc, th);
 1191: 		}
 1192: 		splx(s);
 1193: 	} else {
 1194: 		for (cpu = 0; cpu < ncpus2; cpu++) {
 1195: 			in_pcbnotifyall(&tcbinfo[cpu].listhead, faddr,
 1196: 					inetctlerrmap[cmd], notify);
 1197: 		}
 1198: 	}
 1199: }
 1200: 
 1201: #ifdef INET6
 1202: void
 1203: tcp6_ctlinput(cmd, sa, d)
 1204: 	int cmd;
 1205: 	struct sockaddr *sa;
 1206: 	void *d;
 1207: {
 1208: 	struct tcphdr th;
 1209: 	void (*notify) (struct inpcb *, int) = tcp_notify;
 1210: 	struct ip6_hdr *ip6;
 1211: 	struct mbuf *m;
 1212: 	struct ip6ctlparam *ip6cp = NULL;
 1213: 	const struct sockaddr_in6 *sa6_src = NULL;
 1214: 	int off;
 1215: 	struct tcp_portonly {
 1216: 		u_int16_t th_sport;
 1217: 		u_int16_t th_dport;
 1218: 	} *thp;
 1219: 
 1220: 	if (sa->sa_family != AF_INET6 ||
 1221: 	    sa->sa_len != sizeof(struct sockaddr_in6))
 1222: 		return;
 1223: 
 1224: 	if (cmd == PRC_QUENCH)
 1225: 		notify = tcp_quench;
 1226: 	else if (cmd == PRC_MSGSIZE)
 1227: 		notify = tcp_mtudisc;
 1228: 	else if (!PRC_IS_REDIRECT(cmd) &&
 1229: 		 ((unsigned)cmd > PRC_NCMDS || inet6ctlerrmap[cmd] == 0))
 1230: 		return;
 1231: 
 1232: 	/* if the parameter is from icmp6, decode it. */
 1233: 	if (d != NULL) {
 1234: 		ip6cp = (struct ip6ctlparam *)d;
 1235: 		m = ip6cp->ip6c_m;
 1236: 		ip6 = ip6cp->ip6c_ip6;
 1237: 		off = ip6cp->ip6c_off;
 1238: 		sa6_src = ip6cp->ip6c_src;
 1239: 	} else {
 1240: 		m = NULL;
 1241: 		ip6 = NULL;
 1242: 		off = 0;	/* fool gcc */
 1243: 		sa6_src = &sa6_any;
 1244: 	}
 1245: 
 1246: 	if (ip6) {
 1247: 		struct in_conninfo inc;
 1248: 		/*
 1249: 		 * XXX: We assume that when IPV6 is non NULL,
 1250: 		 * M and OFF are valid.
 1251: 		 */
 1252: 
 1253: 		/* check if we can safely examine src and dst ports */
 1254: 		if (m->m_pkthdr.len < off + sizeof(*thp))
 1255: 			return;
 1256: 
 1257: 		bzero(&th, sizeof(th));
 1258: 		m_copydata(m, off, sizeof(*thp), (caddr_t)&th);
 1259: 
 1260: 		in6_pcbnotify(&tcbinfo[0].listhead, sa, th.th_dport,
 1261: 		    (struct sockaddr *)ip6cp->ip6c_src,
 1262: 		    th.th_sport, cmd, notify);
 1263: 
 1264: 		inc.inc_fport = th.th_dport;
 1265: 		inc.inc_lport = th.th_sport;
 1266: 		inc.inc6_faddr = ((struct sockaddr_in6 *)sa)->sin6_addr;
 1267: 		inc.inc6_laddr = ip6cp->ip6c_src->sin6_addr;
 1268: 		inc.inc_isipv6 = 1;
 1269: 		syncache_unreach(&inc, &th);
 1270: 	} else
 1271: 		in6_pcbnotify(&tcbinfo[0].listhead, sa, 0,
 1272: 		    (const struct sockaddr *)sa6_src, 0, cmd, notify);
 1273: }
 1274: #endif /* INET6 */
 1275: 
 1276: 
 1277: /*
 1278:  * Following is where TCP initial sequence number generation occurs.
 1279:  *
 1280:  * There are two places where we must use initial sequence numbers:
 1281:  * 1.  In SYN-ACK packets.
 1282:  * 2.  In SYN packets.
 1283:  *
 1284:  * All ISNs for SYN-ACK packets are generated by the syncache.  See
 1285:  * tcp_syncache.c for details.
 1286:  *
 1287:  * The ISNs in SYN packets must be monotonic; TIME_WAIT recycling
 1288:  * depends on this property.  In addition, these ISNs should be
 1289:  * unguessable so as to prevent connection hijacking.  To satisfy
 1290:  * the requirements of this situation, the algorithm outlined in
 1291:  * RFC 1948 is used to generate sequence numbers.
 1292:  *
 1293:  * Implementation details:
 1294:  *
 1295:  * Time is based off the system timer, and is corrected so that it
 1296:  * increases by one megabyte per second.  This allows for proper
 1297:  * recycling on high speed LANs while still leaving over an hour
 1298:  * before rollover.
 1299:  *
 1300:  * net.inet.tcp.isn_reseed_interval controls the number of seconds
 1301:  * between seeding of isn_secret.  This is normally set to zero,
 1302:  * as reseeding should not be necessary.
 1303:  *
 1304:  */
 1305: 
 1306: #define ISN_BYTES_PER_SECOND 1048576
 1307: 
 1308: u_char isn_secret[32];
 1309: int isn_last_reseed;
 1310: MD5_CTX isn_ctx;
 1311: 
 1312: tcp_seq
 1313: tcp_new_isn(tp)
 1314: 	struct tcpcb *tp;
 1315: {
 1316: 	u_int32_t md5_buffer[4];
 1317: 	tcp_seq new_isn;
 1318: 
 1319: 	/* Seed if this is the first use, reseed if requested. */
 1320: 	if ((isn_last_reseed == 0) || ((tcp_isn_reseed_interval > 0) &&
 1321: 	     (((u_int)isn_last_reseed + (u_int)tcp_isn_reseed_interval*hz)
 1322: 		< (u_int)ticks))) {
 1323: 		read_random_unlimited(&isn_secret, sizeof(isn_secret));
 1324: 		isn_last_reseed = ticks;
 1325: 	}
 1326: 		
 1327: 	/* Compute the md5 hash and return the ISN. */
 1328: 	MD5Init(&isn_ctx);
 1329: 	MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_fport, sizeof(u_short));
 1330: 	MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_lport, sizeof(u_short));
 1331: #ifdef INET6
 1332: 	if ((tp->t_inpcb->inp_vflag & INP_IPV6) != 0) {
 1333: 		MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->in6p_faddr,
 1334: 			  sizeof(struct in6_addr));
 1335: 		MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->in6p_laddr,
 1336: 			  sizeof(struct in6_addr));
 1337: 	} else
 1338: #endif
 1339: 	{
 1340: 		MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_faddr,
 1341: 			  sizeof(struct in_addr));
 1342: 		MD5Update(&isn_ctx, (u_char *) &tp->t_inpcb->inp_laddr,
 1343: 			  sizeof(struct in_addr));
 1344: 	}
 1345: 	MD5Update(&isn_ctx, (u_char *) &isn_secret, sizeof(isn_secret));
 1346: 	MD5Final((u_char *) &md5_buffer, &isn_ctx);
 1347: 	new_isn = (tcp_seq) md5_buffer[0];
 1348: 	new_isn += ticks * (ISN_BYTES_PER_SECOND / hz);
 1349: 	return new_isn;
 1350: }
 1351: 
 1352: /*
 1353:  * When a source quench is received, close congestion window
 1354:  * to one segment.  We will gradually open it again as we proceed.
 1355:  */
 1356: void
 1357: tcp_quench(inp, errno)
 1358: 	struct inpcb *inp;
 1359: 	int errno;
 1360: {
 1361: 	struct tcpcb *tp = intotcpcb(inp);
 1362: 
 1363: 	if (tp)
 1364: 		tp->snd_cwnd = tp->t_maxseg;
 1365: }
 1366: 
 1367: /*
 1368:  * When a specific ICMP unreachable message is received and the
 1369:  * connection state is SYN-SENT, drop the connection.  This behavior
 1370:  * is controlled by the icmp_may_rst sysctl.
 1371:  */
 1372: void
 1373: tcp_drop_syn_sent(inp, errno)
 1374: 	struct inpcb *inp;
 1375: 	int errno;
 1376: {
 1377: 	struct tcpcb *tp = intotcpcb(inp);
 1378: 
 1379: 	if (tp && tp->t_state == TCPS_SYN_SENT)
 1380: 		tcp_drop(tp, errno);
 1381: }
 1382: 
 1383: /*
 1384:  * When `need fragmentation' ICMP is received, update our idea of the MSS
 1385:  * based on the new value in the route.  Also nudge TCP to send something,
 1386:  * since we know the packet we just sent was dropped.
 1387:  * This duplicates some code in the tcp_mss() function in tcp_input.c.
 1388:  */
 1389: void
 1390: tcp_mtudisc(inp, errno)
 1391: 	struct inpcb *inp;
 1392: 	int errno;
 1393: {
 1394: 	struct tcpcb *tp = intotcpcb(inp);
 1395: 	struct rtentry *rt;
 1396: 	struct rmxp_tao *taop;
 1397: 	struct socket *so = inp->inp_socket;
 1398: 	int offered;
 1399: 	int mss;
 1400: #ifdef INET6
 1401: 	int isipv6 = (tp->t_inpcb->inp_vflag & INP_IPV6) != 0;
 1402: #endif /* INET6 */
 1403: 
 1404: 	if (tp) {
 1405: #ifdef INET6
 1406: 		if (isipv6)
 1407: 			rt = tcp_rtlookup6(&inp->inp_inc);
 1408: 		else
 1409: #endif /* INET6 */
 1410: 		rt = tcp_rtlookup(&inp->inp_inc);
 1411: 		if (!rt || !rt->rt_rmx.rmx_mtu) {
 1412: 			tp->t_maxopd = tp->t_maxseg =
 1413: #ifdef INET6
 1414: 				isipv6 ? tcp_v6mssdflt :
 1415: #endif /* INET6 */
 1416: 				tcp_mssdflt;
 1417: 			return;
 1418: 		}
 1419: 		taop = rmx_taop(rt->rt_rmx);
 1420: 		offered = taop->tao_mssopt;
 1421: 		mss = rt->rt_rmx.rmx_mtu -
 1422: #ifdef INET6
 1423: 			(isipv6 ?
 1424: 			 sizeof(struct ip6_hdr) + sizeof(struct tcphdr) :
 1425: #endif /* INET6 */
 1426: 			 sizeof(struct tcpiphdr)
 1427: #ifdef INET6
 1428: 			 )
 1429: #endif /* INET6 */
 1430: 			;
 1431: 
 1432: 		if (offered)
 1433: 			mss = min(mss, offered);
 1434: 		/*
 1435: 		 * XXX - The above conditional probably violates the TCP
 1436: 		 * spec.  The problem is that, since we don't know the
 1437: 		 * other end's MSS, we are supposed to use a conservative
 1438: 		 * default.  But, if we do that, then MTU discovery will
 1439: 		 * never actually take place, because the conservative
 1440: 		 * default is much less than the MTUs typically seen
 1441: 		 * on the Internet today.  For the moment, we'll sweep
 1442: 		 * this under the carpet.
 1443: 		 *
 1444: 		 * The conservative default might not actually be a problem
 1445: 		 * if the only case this occurs is when sending an initial
 1446: 		 * SYN with options and data to a host we've never talked
 1447: 		 * to before.  Then, they will reply with an MSS value which
 1448: 		 * will get recorded and the new parameters should get
 1449: 		 * recomputed.  For Further Study.
 1450: 		 */
 1451: 		if (tp->t_maxopd <= mss)
 1452: 			return;
 1453: 		tp->t_maxopd = mss;
 1454: 
 1455: 		if ((tp->t_flags & (TF_REQ_TSTMP|TF_NOOPT)) == TF_REQ_TSTMP &&
 1456: 		    (tp->t_flags & TF_RCVD_TSTMP) == TF_RCVD_TSTMP)
 1457: 			mss -= TCPOLEN_TSTAMP_APPA;
 1458: 		if ((tp->t_flags & (TF_REQ_CC|TF_NOOPT)) == TF_REQ_CC &&
 1459: 		    (tp->t_flags & TF_RCVD_CC) == TF_RCVD_CC)
 1460: 			mss -= TCPOLEN_CC_APPA;
 1461: #if	(MCLBYTES & (MCLBYTES - 1)) == 0
 1462: 		if (mss > MCLBYTES)
 1463: 			mss &= ~(MCLBYTES-1);
 1464: #else
 1465: 		if (mss > MCLBYTES)
 1466: 			mss = mss / MCLBYTES * MCLBYTES;
 1467: #endif
 1468: 		if (so->so_snd.sb_hiwat < mss)
 1469: 			mss = so->so_snd.sb_hiwat;
 1470: 
 1471: 		tp->t_maxseg = mss;
 1472: 
 1473: 		tcpstat.tcps_mturesent++;
 1474: 		tp->t_rtttime = 0;
 1475: 		tp->snd_nxt = tp->snd_una;
 1476: 		tcp_output(tp);
 1477: 	}
 1478: }
 1479: 
 1480: /*
 1481:  * Look-up the routing entry to the peer of this inpcb.  If no route
 1482:  * is found and it cannot be allocated the return NULL.  This routine
 1483:  * is called by TCP routines that access the rmx structure and by tcp_mss
 1484:  * to get the interface MTU.
 1485:  */
 1486: struct rtentry *
 1487: tcp_rtlookup(inc)
 1488: 	struct in_conninfo *inc;
 1489: {
 1490: 	struct route *ro;
 1491: 	struct rtentry *rt;
 1492: 
 1493: 	ro = &inc->inc_route;
 1494: 	rt = ro->ro_rt;
 1495: 	if (rt == NULL || !(rt->rt_flags & RTF_UP)) {
 1496: 		/* No route yet, so try to acquire one */
 1497: 		if (inc->inc_faddr.s_addr != INADDR_ANY) {
 1498: 			ro->ro_dst.sa_family = AF_INET;
 1499: 			ro->ro_dst.sa_len = sizeof(struct sockaddr_in);
 1500: 			((struct sockaddr_in *) &ro->ro_dst)->sin_addr =
 1501: 			    inc->inc_faddr;
 1502: 			rtalloc(ro);
 1503: 			rt = ro->ro_rt;
 1504: 		}
 1505: 	}
 1506: 	return rt;
 1507: }
 1508: 
 1509: #ifdef INET6
 1510: struct rtentry *
 1511: tcp_rtlookup6(inc)
 1512: 	struct in_conninfo *inc;
 1513: {
 1514: 	struct route_in6 *ro6;
 1515: 	struct rtentry *rt;
 1516: 
 1517: 	ro6 = &inc->inc6_route;
 1518: 	rt = ro6->ro_rt;
 1519: 	if (rt == NULL || !(rt->rt_flags & RTF_UP)) {
 1520: 		/* No route yet, so try to acquire one */
 1521: 		if (!IN6_IS_ADDR_UNSPECIFIED(&inc->inc6_faddr)) {
 1522: 			ro6->ro_dst.sin6_family = AF_INET6;
 1523: 			ro6->ro_dst.sin6_len = sizeof(struct sockaddr_in6);
 1524: 			ro6->ro_dst.sin6_addr = inc->inc6_faddr;
 1525: 			rtalloc((struct route *)ro6);
 1526: 			rt = ro6->ro_rt;
 1527: 		}
 1528: 	}
 1529: 	return rt;
 1530: }
 1531: #endif /* INET6 */
 1532: 
 1533: #ifdef IPSEC
 1534: /* compute ESP/AH header size for TCP, including outer IP header. */
 1535: size_t
 1536: ipsec_hdrsiz_tcp(tp)
 1537: 	struct tcpcb *tp;
 1538: {
 1539: 	struct inpcb *inp;
 1540: 	struct mbuf *m;
 1541: 	size_t hdrsiz;
 1542: 	struct ip *ip;
 1543: #ifdef INET6
 1544: 	struct ip6_hdr *ip6;
 1545: #endif /* INET6 */
 1546: 	struct tcphdr *th;
 1547: 
 1548: 	if ((tp == NULL) || ((inp = tp->t_inpcb) == NULL))
 1549: 		return 0;
 1550: 	MGETHDR(m, M_DONTWAIT, MT_DATA);
 1551: 	if (!m)
 1552: 		return 0;
 1553: 
 1554: #ifdef INET6
 1555: 	if ((inp->inp_vflag & INP_IPV6) != 0) {
 1556: 		ip6 = mtod(m, struct ip6_hdr *);
 1557: 		th = (struct tcphdr *)(ip6 + 1);
 1558: 		m->m_pkthdr.len = m->m_len =
 1559: 			sizeof(struct ip6_hdr) + sizeof(struct tcphdr);
 1560: 		tcp_fillheaders(tp, ip6, th);
 1561: 		hdrsiz = ipsec6_hdrsiz(m, IPSEC_DIR_OUTBOUND, inp);
 1562: 	} else
 1563: #endif /* INET6 */
 1564:       {
 1565: 	ip = mtod(m, struct ip *);
 1566: 	th = (struct tcphdr *)(ip + 1);
 1567: 	m->m_pkthdr.len = m->m_len = sizeof(struct tcpiphdr);
 1568: 	tcp_fillheaders(tp, ip, th);
 1569: 	hdrsiz = ipsec4_hdrsiz(m, IPSEC_DIR_OUTBOUND, inp);
 1570:       }
 1571: 
 1572: 	m_free(m);
 1573: 	return hdrsiz;
 1574: }
 1575: #endif /*IPSEC*/
 1576: 
 1577: /*
 1578:  * Return a pointer to the cached information about the remote host.
 1579:  * The cached information is stored in the protocol specific part of
 1580:  * the route metrics.
 1581:  */
 1582: struct rmxp_tao *
 1583: tcp_gettaocache(inc)
 1584: 	struct in_conninfo *inc;
 1585: {
 1586: 	struct rtentry *rt;
 1587: 
 1588: #ifdef INET6
 1589: 	if (inc->inc_isipv6)
 1590: 		rt = tcp_rtlookup6(inc);
 1591: 	else
 1592: #endif /* INET6 */
 1593: 	rt = tcp_rtlookup(inc);
 1594: 
 1595: 	/* Make sure this is a host route and is up. */
 1596: 	if (rt == NULL ||
 1597: 	    (rt->rt_flags & (RTF_UP|RTF_HOST)) != (RTF_UP|RTF_HOST))
 1598: 		return NULL;
 1599: 
 1600: 	return rmx_taop(rt->rt_rmx);
 1601: }
 1602: 
 1603: /*
 1604:  * Clear all the TAO cache entries, called from tcp_init.
 1605:  *
 1606:  * XXX
 1607:  * This routine is just an empty one, because we assume that the routing
 1608:  * routing tables are initialized at the same time when TCP, so there is
 1609:  * nothing in the cache left over.
 1610:  */
 1611: static void
 1612: tcp_cleartaocache()
 1613: {
 1614: }
 1615: 
 1616: /*
 1617:  * TCP BANDWIDTH DELAY PRODUCT WINDOW LIMITING
 1618:  *
 1619:  * This code attempts to calculate the bandwidth-delay product as a
 1620:  * means of determining the optimal window size to maximize bandwidth,
 1621:  * minimize RTT, and avoid the over-allocation of buffers on interfaces and
 1622:  * routers.  This code also does a fairly good job keeping RTTs in check
 1623:  * across slow links like modems.  We implement an algorithm which is very
 1624:  * similar (but not meant to be) TCP/Vegas.  The code operates on the
 1625:  * transmitter side of a TCP connection and so only effects the transmit
 1626:  * side of the connection.
 1627:  *
 1628:  * BACKGROUND:  TCP makes no provision for the management of buffer space
 1629:  * at the end points or at the intermediate routers and switches.  A TCP 
 1630:  * stream, whether using NewReno or not, will eventually buffer as
 1631:  * many packets as it is able and the only reason this typically works is
 1632:  * due to the fairly small default buffers made available for a connection
 1633:  * (typicaly 16K or 32K).  As machines use larger windows and/or window
 1634:  * scaling it is now fairly easy for even a single TCP connection to blow-out
 1635:  * all available buffer space not only on the local interface, but on 
 1636:  * intermediate routers and switches as well.  NewReno makes a misguided
 1637:  * attempt to 'solve' this problem by waiting for an actual failure to occur,
 1638:  * then backing off, then steadily increasing the window again until another
 1639:  * failure occurs, ad-infinitum.  This results in terrible oscillation that
 1640:  * is only made worse as network loads increase and the idea of intentionally
 1641:  * blowing out network buffers is, frankly, a terrible way to manage network
 1642:  * resources.
 1643:  *
 1644:  * It is far better to limit the transmit window prior to the failure
 1645:  * condition being achieved.  There are two general ways to do this:  First
 1646:  * you can 'scan' through different transmit window sizes and locate the
 1647:  * point where the RTT stops increasing, indicating that you have filled the
 1648:  * pipe, then scan backwards until you note that RTT stops decreasing, then
 1649:  * repeat ad-infinitum.  This method works in principle but has severe
 1650:  * implementation issues due to RTT variances, timer granularity, and
 1651:  * instability in the algorithm which can lead to many false positives and
 1652:  * create oscillations as well as interact badly with other TCP streams
 1653:  * implementing the same algorithm.
 1654:  *
 1655:  * The second method is to limit the window to the bandwidth delay product
 1656:  * of the link.  This is the method we implement.  RTT variances and our
 1657:  * own manipulation of the congestion window, bwnd, can potentially 
 1658:  * destabilize the algorithm.  For this reason we have to stabilize the
 1659:  * elements used to calculate the window.  We do this by using the minimum
 1660:  * observed RTT, the long term average of the observed bandwidth, and
 1661:  * by adding two segments worth of slop.  It isn't perfect but it is able
 1662:  * to react to changing conditions and gives us a very stable basis on
 1663:  * which to extend the algorithm.
 1664:  */
 1665: void
 1666: tcp_xmit_bandwidth_limit(struct tcpcb *tp, tcp_seq ack_seq)
 1667: {
 1668: 	u_long bw;
 1669: 	u_long bwnd;
 1670: 	int save_ticks;
 1671: 
 1672: 	/*
 1673: 	 * If inflight_enable is disabled in the middle of a tcp connection,
 1674: 	 * make sure snd_bwnd is effectively disabled.
 1675: 	 */
 1676: 	if (tcp_inflight_enable == 0) {
 1677: 		tp->snd_bwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT;
 1678: 		tp->snd_bandwidth = 0;
 1679: 		return;
 1680: 	}
 1681: 
 1682: 	/*
 1683: 	 * Figure out the bandwidth.  Due to the tick granularity this
 1684: 	 * is a very rough number and it MUST be averaged over a fairly
 1685: 	 * long period of time.  XXX we need to take into account a link
 1686: 	 * that is not using all available bandwidth, but for now our
 1687: 	 * slop will ramp us up if this case occurs and the bandwidth later
 1688: 	 * increases.
 1689: 	 *
 1690: 	 * Note: if ticks rollover 'bw' may wind up negative.  We must
 1691: 	 * effectively reset t_bw_rtttime for this case.
 1692: 	 */
 1693: 	save_ticks = ticks;
 1694: 	if ((u_int)(save_ticks - tp->t_bw_rtttime) < 1)
 1695: 		return;
 1696: 
 1697: 	bw = (int64_t)(ack_seq - tp->t_bw_rtseq) * hz / 
 1698: 	    (save_ticks - tp->t_bw_rtttime);
 1699: 	tp->t_bw_rtttime = save_ticks;
 1700: 	tp->t_bw_rtseq = ack_seq;
 1701: 	if (tp->t_bw_rtttime == 0 || (int)bw < 0)
 1702: 		return;
 1703: 	bw = ((int64_t)tp->snd_bandwidth * 15 + bw) >> 4;
 1704: 
 1705: 	tp->snd_bandwidth = bw;
 1706: 
 1707: 	/*
 1708: 	 * Calculate the semi-static bandwidth delay product, plus two maximal
 1709: 	 * segments.  The additional slop puts us squarely in the sweet
 1710: 	 * spot and also handles the bandwidth run-up case.  Without the
 1711: 	 * slop we could be locking ourselves into a lower bandwidth.
 1712: 	 *
 1713: 	 * Situations Handled:
 1714: 	 *	(1) Prevents over-queueing of packets on LANs, especially on
 1715: 	 *	    high speed LANs, allowing larger TCP buffers to be
 1716: 	 *	    specified, and also does a good job preventing 
 1717: 	 *	    over-queueing of packets over choke points like modems
 1718: 	 *	    (at least for the transmit side).
 1719: 	 *
 1720: 	 *	(2) Is able to handle changing network loads (bandwidth
 1721: 	 *	    drops so bwnd drops, bandwidth increases so bwnd
 1722: 	 *	    increases).
 1723: 	 *
 1724: 	 *	(3) Theoretically should stabilize in the face of multiple
 1725: 	 *	    connections implementing the same algorithm (this may need
 1726: 	 *	    a little work).
 1727: 	 *
 1728: 	 *	(4) Stability value (defaults to 20 = 2 maximal packets) can 
 1729: 	 *	    be adjusted with a sysctl but typically only needs to be on
 1730: 	 *	    very slow connections.  A value no smaller then 5 should
 1731: 	 *	    be used, but only reduce this default if you have no other
 1732: 	 *	    choice.
 1733: 	 */
 1734: #define USERTT	((tp->t_srtt + tp->t_rttbest) / 2)
 1735: 	bwnd = (int64_t)bw * USERTT / (hz << TCP_RTT_SHIFT) + tcp_inflight_stab * (int)tp->t_maxseg / 10;
 1736: #undef USERTT
 1737: 
 1738: 	if (tcp_inflight_debug > 0) {
 1739: 		static int ltime;
 1740: 		if ((u_int)(ticks - ltime) >= hz / tcp_inflight_debug) {
 1741: 			ltime = ticks;
 1742: 			printf("%p bw %ld rttbest %d srtt %d bwnd %ld\n",
 1743: 			    tp,
 1744: 			    bw,
 1745: 			    tp->t_rttbest,
 1746: 			    tp->t_srtt,
 1747: 			    bwnd
 1748: 			);
 1749: 		}
 1750: 	}
 1751: 	if ((long)bwnd < tcp_inflight_min)
 1752: 		bwnd = tcp_inflight_min;
 1753: 	if (bwnd > tcp_inflight_max)
 1754: 		bwnd = tcp_inflight_max;
 1755: 	if ((long)bwnd < tp->t_maxseg * 2)
 1756: 		bwnd = tp->t_maxseg * 2;
 1757: 	tp->snd_bwnd = bwnd;
 1758: }