tcp_var.h revision 63431
1/* 2 * Copyright (c) 1982, 1986, 1993, 1994, 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_var.h 8.4 (Berkeley) 5/24/95 34 * $FreeBSD: head/sys/netinet/tcp_var.h 63431 2000-07-18 16:43:29Z sheldonh $ 35 */ 36 37#ifndef _NETINET_TCP_VAR_H_ 38#define _NETINET_TCP_VAR_H_ 39/* 40 * Kernel variables for tcp. 41 */ 42 43/* TCP segment queue entry */ 44struct tseg_qent { 45 LIST_ENTRY(tseg_qent) tqe_q; 46 int tqe_len; /* TCP segment data length */ 47 struct tcphdr *tqe_th; /* a pointer to tcp header */ 48 struct mbuf *tqe_m; /* mbuf contains packet */ 49}; 50LIST_HEAD(tsegqe_head, tseg_qent); 51#ifdef MALLOC_DECLARE 52MALLOC_DECLARE(M_TSEGQ); 53#endif 54 55struct tcptemp { 56 u_char tt_ipgen[40]; /* the size must be of max ip header, now IPv6 */ 57 struct tcphdr tt_t; 58}; 59 60#define tcp6cb tcpcb /* for KAME src sync over BSD*'s */ 61 62/* 63 * Tcp control block, one per tcp; fields: 64 * Organized for 16 byte cacheline efficiency. 65 */ 66struct tcpcb { 67 struct tsegqe_head t_segq; 68 int t_dupacks; /* consecutive dup acks recd */ 69 struct tcptemp *t_template; /* skeletal packet for transmit */ 70 71 struct callout *tt_rexmt; /* retransmit timer */ 72 struct callout *tt_persist; /* retransmit persistence */ 73 struct callout *tt_keep; /* keepalive */ 74 struct callout *tt_2msl; /* 2*msl TIME_WAIT timer */ 75 struct callout *tt_delack; /* delayed ACK timer */ 76 77 struct inpcb *t_inpcb; /* back pointer to internet pcb */ 78 int t_state; /* state of this connection */ 79 u_int t_flags; 80#define TF_ACKNOW 0x00001 /* ack peer immediately */ 81#define TF_DELACK 0x00002 /* ack, but try to delay it */ 82#define TF_NODELAY 0x00004 /* don't delay packets to coalesce */ 83#define TF_NOOPT 0x00008 /* don't use tcp options */ 84#define TF_SENTFIN 0x00010 /* have sent FIN */ 85#define TF_REQ_SCALE 0x00020 /* have/will request window scaling */ 86#define TF_RCVD_SCALE 0x00040 /* other side has requested scaling */ 87#define TF_REQ_TSTMP 0x00080 /* have/will request timestamps */ 88#define TF_RCVD_TSTMP 0x00100 /* a timestamp was received in SYN */ 89#define TF_SACK_PERMIT 0x00200 /* other side said I could SACK */ 90#define TF_NEEDSYN 0x00400 /* send SYN (implicit state) */ 91#define TF_NEEDFIN 0x00800 /* send FIN (implicit state) */ 92#define TF_NOPUSH 0x01000 /* don't push */ 93#define TF_REQ_CC 0x02000 /* have/will request CC */ 94#define TF_RCVD_CC 0x04000 /* a CC was received in SYN */ 95#define TF_SENDCCNEW 0x08000 /* send CCnew instead of CC in SYN */ 96#define TF_MORETOCOME 0x10000 /* More data to be appended to sock */ 97 int t_force; /* 1 if forcing out a byte */ 98 99 tcp_seq snd_una; /* send unacknowledged */ 100 tcp_seq snd_max; /* highest sequence number sent; 101 * used to recognize retransmits 102 */ 103 tcp_seq snd_nxt; /* send next */ 104 tcp_seq snd_up; /* send urgent pointer */ 105 106 tcp_seq snd_wl1; /* window update seg seq number */ 107 tcp_seq snd_wl2; /* window update seg ack number */ 108 tcp_seq iss; /* initial send sequence number */ 109 tcp_seq irs; /* initial receive sequence number */ 110 111 tcp_seq rcv_nxt; /* receive next */ 112 tcp_seq rcv_adv; /* advertised window */ 113 u_long rcv_wnd; /* receive window */ 114 tcp_seq rcv_up; /* receive urgent pointer */ 115 116 u_long snd_wnd; /* send window */ 117 u_long snd_cwnd; /* congestion-controlled window */ 118 u_long snd_ssthresh; /* snd_cwnd size threshold for 119 * for slow start exponential to 120 * linear switch 121 */ 122 tcp_seq snd_recover; /* for use in fast recovery */ 123 124 u_int t_maxopd; /* mss plus options */ 125 126 u_long t_rcvtime; /* inactivity time */ 127 u_long t_starttime; /* time connection was established */ 128 int t_rtttime; /* round trip time */ 129 tcp_seq t_rtseq; /* sequence number being timed */ 130 131 int t_rxtcur; /* current retransmit value (ticks) */ 132 u_int t_maxseg; /* maximum segment size */ 133 int t_srtt; /* smoothed round-trip time */ 134 int t_rttvar; /* variance in round-trip time */ 135 136 int t_rxtshift; /* log(2) of rexmt exp. backoff */ 137 u_int t_rttmin; /* minimum rtt allowed */ 138 u_long t_rttupdated; /* number of times rtt sampled */ 139 u_long max_sndwnd; /* largest window peer has offered */ 140 141 int t_softerror; /* possible error not yet reported */ 142/* out-of-band data */ 143 char t_oobflags; /* have some */ 144 char t_iobc; /* input character */ 145#define TCPOOB_HAVEDATA 0x01 146#define TCPOOB_HADDATA 0x02 147/* RFC 1323 variables */ 148 u_char snd_scale; /* window scaling for send window */ 149 u_char rcv_scale; /* window scaling for recv window */ 150 u_char request_r_scale; /* pending window scaling */ 151 u_char requested_s_scale; 152 u_long ts_recent; /* timestamp echo data */ 153 154 u_long ts_recent_age; /* when last updated */ 155 tcp_seq last_ack_sent; 156/* RFC 1644 variables */ 157 tcp_cc cc_send; /* send connection count */ 158 tcp_cc cc_recv; /* receive connection count */ 159/* experimental */ 160 u_long snd_cwnd_prev; /* cwnd prior to retransmit */ 161 u_long snd_ssthresh_prev; /* ssthresh prior to retransmit */ 162 u_long t_badrxtwin; /* window for retransmit recovery */ 163}; 164 165/* 166 * Structure to hold TCP options that are only used during segment 167 * processing (in tcp_input), but not held in the tcpcb. 168 * It's basically used to reduce the number of parameters 169 * to tcp_dooptions. 170 */ 171struct tcpopt { 172 u_long to_flag; /* which options are present */ 173#define TOF_TS 0x0001 /* timestamp */ 174#define TOF_CC 0x0002 /* CC and CCnew are exclusive */ 175#define TOF_CCNEW 0x0004 176#define TOF_CCECHO 0x0008 177 u_long to_tsval; 178 u_long to_tsecr; 179 tcp_cc to_cc; /* holds CC or CCnew */ 180 tcp_cc to_ccecho; 181}; 182 183/* 184 * The TAO cache entry which is stored in the protocol family specific 185 * portion of the route metrics. 186 */ 187struct rmxp_tao { 188 tcp_cc tao_cc; /* latest CC in valid SYN */ 189 tcp_cc tao_ccsent; /* latest CC sent to peer */ 190 u_short tao_mssopt; /* peer's cached MSS */ 191#ifdef notyet 192 u_short tao_flags; /* cache status flags */ 193#define TAOF_DONT 0x0001 /* peer doesn't understand rfc1644 */ 194#define TAOF_OK 0x0002 /* peer does understand rfc1644 */ 195#define TAOF_UNDEF 0 /* we don't know yet */ 196#endif /* notyet */ 197}; 198#define rmx_taop(r) ((struct rmxp_tao *)(r).rmx_filler) 199 200#define intotcpcb(ip) ((struct tcpcb *)(ip)->inp_ppcb) 201#define sototcpcb(so) (intotcpcb(sotoinpcb(so))) 202 203/* 204 * The smoothed round-trip time and estimated variance 205 * are stored as fixed point numbers scaled by the values below. 206 * For convenience, these scales are also used in smoothing the average 207 * (smoothed = (1/scale)sample + ((scale-1)/scale)smoothed). 208 * With these scales, srtt has 3 bits to the right of the binary point, 209 * and thus an "ALPHA" of 0.875. rttvar has 2 bits to the right of the 210 * binary point, and is smoothed with an ALPHA of 0.75. 211 */ 212#define TCP_RTT_SCALE 32 /* multiplier for srtt; 3 bits frac. */ 213#define TCP_RTT_SHIFT 5 /* shift for srtt; 3 bits frac. */ 214#define TCP_RTTVAR_SCALE 16 /* multiplier for rttvar; 2 bits */ 215#define TCP_RTTVAR_SHIFT 4 /* shift for rttvar; 2 bits */ 216#define TCP_DELTA_SHIFT 2 /* see tcp_input.c */ 217 218/* 219 * The initial retransmission should happen at rtt + 4 * rttvar. 220 * Because of the way we do the smoothing, srtt and rttvar 221 * will each average +1/2 tick of bias. When we compute 222 * the retransmit timer, we want 1/2 tick of rounding and 223 * 1 extra tick because of +-1/2 tick uncertainty in the 224 * firing of the timer. The bias will give us exactly the 225 * 1.5 tick we need. But, because the bias is 226 * statistical, we have to test that we don't drop below 227 * the minimum feasible timer (which is 2 ticks). 228 * This version of the macro adapted from a paper by Lawrence 229 * Brakmo and Larry Peterson which outlines a problem caused 230 * by insufficient precision in the original implementation, 231 * which results in inappropriately large RTO values for very 232 * fast networks. 233 */ 234#define TCP_REXMTVAL(tp) \ 235 max((tp)->t_rttmin, (((tp)->t_srtt >> (TCP_RTT_SHIFT - TCP_DELTA_SHIFT)) \ 236 + (tp)->t_rttvar) >> TCP_DELTA_SHIFT) 237 238/* 239 * TCP statistics. 240 * Many of these should be kept per connection, 241 * but that's inconvenient at the moment. 242 */ 243struct tcpstat { 244 u_long tcps_connattempt; /* connections initiated */ 245 u_long tcps_accepts; /* connections accepted */ 246 u_long tcps_connects; /* connections established */ 247 u_long tcps_drops; /* connections dropped */ 248 u_long tcps_conndrops; /* embryonic connections dropped */ 249 u_long tcps_closed; /* conn. closed (includes drops) */ 250 u_long tcps_segstimed; /* segs where we tried to get rtt */ 251 u_long tcps_rttupdated; /* times we succeeded */ 252 u_long tcps_delack; /* delayed acks sent */ 253 u_long tcps_timeoutdrop; /* conn. dropped in rxmt timeout */ 254 u_long tcps_rexmttimeo; /* retransmit timeouts */ 255 u_long tcps_persisttimeo; /* persist timeouts */ 256 u_long tcps_keeptimeo; /* keepalive timeouts */ 257 u_long tcps_keepprobe; /* keepalive probes sent */ 258 u_long tcps_keepdrops; /* connections dropped in keepalive */ 259 260 u_long tcps_sndtotal; /* total packets sent */ 261 u_long tcps_sndpack; /* data packets sent */ 262 u_long tcps_sndbyte; /* data bytes sent */ 263 u_long tcps_sndrexmitpack; /* data packets retransmitted */ 264 u_long tcps_sndrexmitbyte; /* data bytes retransmitted */ 265 u_long tcps_sndacks; /* ack-only packets sent */ 266 u_long tcps_sndprobe; /* window probes sent */ 267 u_long tcps_sndurg; /* packets sent with URG only */ 268 u_long tcps_sndwinup; /* window update-only packets sent */ 269 u_long tcps_sndctrl; /* control (SYN|FIN|RST) packets sent */ 270 271 u_long tcps_rcvtotal; /* total packets received */ 272 u_long tcps_rcvpack; /* packets received in sequence */ 273 u_long tcps_rcvbyte; /* bytes received in sequence */ 274 u_long tcps_rcvbadsum; /* packets received with ccksum errs */ 275 u_long tcps_rcvbadoff; /* packets received with bad offset */ 276 u_long tcps_rcvmemdrop; /* packets dropped for lack of memory */ 277 u_long tcps_rcvshort; /* packets received too short */ 278 u_long tcps_rcvduppack; /* duplicate-only packets received */ 279 u_long tcps_rcvdupbyte; /* duplicate-only bytes received */ 280 u_long tcps_rcvpartduppack; /* packets with some duplicate data */ 281 u_long tcps_rcvpartdupbyte; /* dup. bytes in part-dup. packets */ 282 u_long tcps_rcvoopack; /* out-of-order packets received */ 283 u_long tcps_rcvoobyte; /* out-of-order bytes received */ 284 u_long tcps_rcvpackafterwin; /* packets with data after window */ 285 u_long tcps_rcvbyteafterwin; /* bytes rcvd after window */ 286 u_long tcps_rcvafterclose; /* packets rcvd after "close" */ 287 u_long tcps_rcvwinprobe; /* rcvd window probe packets */ 288 u_long tcps_rcvdupack; /* rcvd duplicate acks */ 289 u_long tcps_rcvacktoomuch; /* rcvd acks for unsent data */ 290 u_long tcps_rcvackpack; /* rcvd ack packets */ 291 u_long tcps_rcvackbyte; /* bytes acked by rcvd acks */ 292 u_long tcps_rcvwinupd; /* rcvd window update packets */ 293 u_long tcps_pawsdrop; /* segments dropped due to PAWS */ 294 u_long tcps_predack; /* times hdr predict ok for acks */ 295 u_long tcps_preddat; /* times hdr predict ok for data pkts */ 296 u_long tcps_pcbcachemiss; 297 u_long tcps_cachedrtt; /* times cached RTT in route updated */ 298 u_long tcps_cachedrttvar; /* times cached rttvar updated */ 299 u_long tcps_cachedssthresh; /* times cached ssthresh updated */ 300 u_long tcps_usedrtt; /* times RTT initialized from route */ 301 u_long tcps_usedrttvar; /* times RTTVAR initialized from rt */ 302 u_long tcps_usedssthresh; /* times ssthresh initialized from rt*/ 303 u_long tcps_persistdrop; /* timeout in persist state */ 304 u_long tcps_badsyn; /* bogus SYN, e.g. premature ACK */ 305 u_long tcps_mturesent; /* resends due to MTU discovery */ 306 u_long tcps_listendrop; /* listen queue overflows */ 307}; 308 309/* 310 * TCB structure exported to user-land via sysctl(3). 311 * Evil hack: declare only if in_pcb.h and sys/socketvar.h have been 312 * included. Not all of our clients do. 313 */ 314#if defined(_NETINET_IN_PCB_H_) && defined(_SYS_SOCKETVAR_H_) 315struct xtcpcb { 316 size_t xt_len; 317 struct inpcb xt_inp; 318 struct tcpcb xt_tp; 319 struct xsocket xt_socket; 320 u_quad_t xt_alignment_hack; 321}; 322#endif 323 324/* 325 * Names for TCP sysctl objects 326 */ 327#define TCPCTL_DO_RFC1323 1 /* use RFC-1323 extensions */ 328#define TCPCTL_DO_RFC1644 2 /* use RFC-1644 extensions */ 329#define TCPCTL_MSSDFLT 3 /* MSS default */ 330#define TCPCTL_STATS 4 /* statistics (read-only) */ 331#define TCPCTL_RTTDFLT 5 /* default RTT estimate */ 332#define TCPCTL_KEEPIDLE 6 /* keepalive idle timer */ 333#define TCPCTL_KEEPINTVL 7 /* interval to send keepalives */ 334#define TCPCTL_SENDSPACE 8 /* send buffer space */ 335#define TCPCTL_RECVSPACE 9 /* receive buffer space */ 336#define TCPCTL_KEEPINIT 10 /* timeout for establishing syn */ 337#define TCPCTL_PCBLIST 11 /* list of all outstanding PCBs */ 338#define TCPCTL_DELACKTIME 12 /* time before sending delayed ACK */ 339#define TCPCTL_V6MSSDFLT 13 /* MSS default for IPv6 */ 340#define TCPCTL_MAXID 14 341 342#define TCPCTL_NAMES { \ 343 { 0, 0 }, \ 344 { "rfc1323", CTLTYPE_INT }, \ 345 { "rfc1644", CTLTYPE_INT }, \ 346 { "mssdflt", CTLTYPE_INT }, \ 347 { "stats", CTLTYPE_STRUCT }, \ 348 { "rttdflt", CTLTYPE_INT }, \ 349 { "keepidle", CTLTYPE_INT }, \ 350 { "keepintvl", CTLTYPE_INT }, \ 351 { "sendspace", CTLTYPE_INT }, \ 352 { "recvspace", CTLTYPE_INT }, \ 353 { "keepinit", CTLTYPE_INT }, \ 354 { "pcblist", CTLTYPE_STRUCT }, \ 355 { "delacktime", CTLTYPE_INT }, \ 356 { "v6mssdflt", CTLTYPE_INT }, \ 357} 358 359 360#ifdef _KERNEL 361#ifdef SYSCTL_DECL 362SYSCTL_DECL(_net_inet_tcp); 363#endif 364 365extern struct inpcbhead tcb; /* head of queue of active tcpcb's */ 366extern struct inpcbinfo tcbinfo; 367extern struct tcpstat tcpstat; /* tcp statistics */ 368extern int tcp_mssdflt; /* XXX */ 369extern int tcp_delack_enabled; 370extern int tcp_do_newreno; 371extern int ss_fltsz; 372extern int ss_fltsz_local; 373 374void tcp_canceltimers __P((struct tcpcb *)); 375struct tcpcb * 376 tcp_close __P((struct tcpcb *)); 377void tcp_ctlinput __P((int, struct sockaddr *, void *)); 378int tcp_ctloutput __P((struct socket *, struct sockopt *)); 379struct tcpcb * 380 tcp_drop __P((struct tcpcb *, int)); 381void tcp_drain __P((void)); 382void tcp_fasttimo __P((void)); 383struct rmxp_tao * 384 tcp_gettaocache __P((struct inpcb *)); 385void tcp_init __P((void)); 386void tcp_input __P((struct mbuf *, int, int)); 387void tcp_mss __P((struct tcpcb *, int)); 388int tcp_mssopt __P((struct tcpcb *)); 389void tcp_mtudisc __P((struct inpcb *, int)); 390struct tcpcb * 391 tcp_newtcpcb __P((struct inpcb *)); 392int tcp_output __P((struct tcpcb *)); 393void tcp_quench __P((struct inpcb *, int)); 394void tcp_respond __P((struct tcpcb *, void *, 395 struct tcphdr *, struct mbuf *, tcp_seq, tcp_seq, int)); 396struct rtentry * 397 tcp_rtlookup __P((struct inpcb *)); 398void tcp_setpersist __P((struct tcpcb *)); 399void tcp_slowtimo __P((void)); 400struct tcptemp * 401 tcp_template __P((struct tcpcb *)); 402struct tcpcb * 403 tcp_timers __P((struct tcpcb *, int)); 404void tcp_trace __P((int, int, struct tcpcb *, void *, struct tcphdr *, 405 int)); 406 407extern struct pr_usrreqs tcp_usrreqs; 408extern u_long tcp_sendspace; 409extern u_long tcp_recvspace; 410 411#endif /* _KERNEL */ 412 413#endif /* _NETINET_TCP_VAR_H_ */ 414