1 /* 2 * Copyright (c) 1982, 1986 Regents of the University of California. 3 * 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 7.10 (Berkeley) 6/28/90 34 */ 35 36 #ifndef _NETINET_TCP_VAR_H_ 37 #define _NETINET_TCP_VAR_H_ 38 39 /* 40 * Kernel variables for tcp. 41 */ 42 43 /* 44 * Tcp control block, one per tcp; fields: 45 */ 46 struct tcpcb { 47 struct tcpiphdr *seg_next; /* sequencing queue */ 48 struct tcpiphdr *seg_prev; 49 short t_state; /* state of this connection */ 50 short t_timer[TCPT_NTIMERS]; /* tcp timers */ 51 short t_rxtshift; /* log(2) of rexmt exp. backoff */ 52 short t_rxtcur; /* current retransmit value */ 53 short t_dupacks; /* consecutive dup acks recd */ 54 u_short t_maxseg; /* maximum segment size */ 55 char t_force; /* 1 if forcing out a byte */ 56 u_char t_flags; 57 #define TF_ACKNOW 0x01 /* ack peer immediately */ 58 #define TF_DELACK 0x02 /* ack, but try to delay it */ 59 #define TF_NODELAY 0x04 /* don't delay packets to coalesce */ 60 #define TF_NOOPT 0x08 /* don't use tcp options */ 61 #define TF_SENTFIN 0x10 /* have sent FIN */ 62 struct tcpiphdr *t_template; /* skeletal packet for transmit */ 63 struct inpcb *t_inpcb; /* back pointer to internet pcb */ 64 /* 65 * The following fields are used as in the protocol specification. 66 * See RFC783, Dec. 1981, page 21. 67 */ 68 /* send sequence variables */ 69 tcp_seq snd_una; /* send unacknowledged */ 70 tcp_seq snd_nxt; /* send next */ 71 tcp_seq snd_up; /* send urgent pointer */ 72 tcp_seq snd_wl1; /* window update seg seq number */ 73 tcp_seq snd_wl2; /* window update seg ack number */ 74 tcp_seq iss; /* initial send sequence number */ 75 u_short snd_wnd; /* send window */ 76 /* receive sequence variables */ 77 u_short rcv_wnd; /* receive window */ 78 tcp_seq rcv_nxt; /* receive next */ 79 tcp_seq rcv_up; /* receive urgent pointer */ 80 tcp_seq irs; /* initial receive sequence number */ 81 /* 82 * Additional variables for this implementation. 83 */ 84 /* receive variables */ 85 tcp_seq rcv_adv; /* advertised window */ 86 /* retransmit variables */ 87 tcp_seq snd_max; /* highest sequence number sent; 88 * used to recognize retransmits 89 */ 90 /* congestion control (for slow start, source quench, retransmit after loss) */ 91 u_short snd_cwnd; /* congestion-controlled window */ 92 u_short snd_ssthresh; /* snd_cwnd size threshhold for 93 * for slow start exponential to 94 * linear switch 95 */ 96 /* 97 * transmit timing stuff. See below for scale of srtt and rttvar. 98 * "Variance" is actually smoothed difference. 99 */ 100 short t_idle; /* inactivity time */ 101 short t_rtt; /* round trip time */ 102 tcp_seq t_rtseq; /* sequence number being timed */ 103 short t_srtt; /* smoothed round-trip time */ 104 short t_rttvar; /* variance in round-trip time */ 105 u_short t_rttmin; /* minimum rtt allowed */ 106 u_short max_sndwnd; /* largest window peer has offered */ 107 108 /* out-of-band data */ 109 char t_oobflags; /* have some */ 110 char t_iobc; /* input character */ 111 #define TCPOOB_HAVEDATA 0x01 112 #define TCPOOB_HADDATA 0x02 113 short t_softerror; /* possible error not yet reported */ 114 }; 115 116 #define intotcpcb(ip) ((struct tcpcb *)(ip)->inp_ppcb) 117 #define sototcpcb(so) (intotcpcb(sotoinpcb(so))) 118 119 /* 120 * The smoothed round-trip time and estimated variance 121 * are stored as fixed point numbers scaled by the values below. 122 * For convenience, these scales are also used in smoothing the average 123 * (smoothed = (1/scale)sample + ((scale-1)/scale)smoothed). 124 * With these scales, srtt has 3 bits to the right of the binary point, 125 * and thus an "ALPHA" of 0.875. rttvar has 2 bits to the right of the 126 * binary point, and is smoothed with an ALPHA of 0.75. 127 */ 128 #define TCP_RTT_SCALE 8 /* multiplier for srtt; 3 bits frac. */ 129 #define TCP_RTT_SHIFT 3 /* shift for srtt; 3 bits frac. */ 130 #define TCP_RTTVAR_SCALE 4 /* multiplier for rttvar; 2 bits */ 131 #define TCP_RTTVAR_SHIFT 2 /* multiplier for rttvar; 2 bits */ 132 133 /* 134 * The initial retransmission should happen at rtt + 4 * rttvar. 135 * Because of the way we do the smoothing, srtt and rttvar 136 * will each average +1/2 tick of bias. When we compute 137 * the retransmit timer, we want 1/2 tick of rounding and 138 * 1 extra tick because of +-1/2 tick uncertainty in the 139 * firing of the timer. The bias will give us exactly the 140 * 1.5 tick we need. But, because the bias is 141 * statistical, we have to test that we don't drop below 142 * the minimum feasible timer (which is 2 ticks). 143 * This macro assumes that the value of TCP_RTTVAR_SCALE 144 * is the same as the multiplier for rttvar. 145 */ 146 #define TCP_REXMTVAL(tp) \ 147 (((tp)->t_srtt >> TCP_RTT_SHIFT) + (tp)->t_rttvar) 148 149 /* XXX 150 * We want to avoid doing m_pullup on incoming packets but that 151 * means avoiding dtom on the tcp reassembly code. That in turn means 152 * keeping an mbuf pointer in the reassembly queue (since we might 153 * have a cluster). As a quick hack, the source & destination 154 * port numbers (which are no longer needed once we've located the 155 * tcpcb) are overlayed with an mbuf pointer. 156 */ 157 #define REASS_MBUF(ti) (*(struct mbuf **)&((ti)->ti_t)) 158 159 /* 160 * TCP statistics. 161 * Many of these should be kept per connection, 162 * but that's inconvenient at the moment. 163 */ 164 struct tcpstat { 165 u_long tcps_connattempt; /* connections initiated */ 166 u_long tcps_accepts; /* connections accepted */ 167 u_long tcps_connects; /* connections established */ 168 u_long tcps_drops; /* connections dropped */ 169 u_long tcps_conndrops; /* embryonic connections dropped */ 170 u_long tcps_closed; /* conn. closed (includes drops) */ 171 u_long tcps_segstimed; /* segs where we tried to get rtt */ 172 u_long tcps_rttupdated; /* times we succeeded */ 173 u_long tcps_delack; /* delayed acks sent */ 174 u_long tcps_timeoutdrop; /* conn. dropped in rxmt timeout */ 175 u_long tcps_rexmttimeo; /* retransmit timeouts */ 176 u_long tcps_persisttimeo; /* persist timeouts */ 177 u_long tcps_keeptimeo; /* keepalive timeouts */ 178 u_long tcps_keepprobe; /* keepalive probes sent */ 179 u_long tcps_keepdrops; /* connections dropped in keepalive */ 180 181 u_long tcps_sndtotal; /* total packets sent */ 182 u_long tcps_sndpack; /* data packets sent */ 183 u_long tcps_sndbyte; /* data bytes sent */ 184 u_long tcps_sndrexmitpack; /* data packets retransmitted */ 185 u_long tcps_sndrexmitbyte; /* data bytes retransmitted */ 186 u_long tcps_sndacks; /* ack-only packets sent */ 187 u_long tcps_sndprobe; /* window probes sent */ 188 u_long tcps_sndurg; /* packets sent with URG only */ 189 u_long tcps_sndwinup; /* window update-only packets sent */ 190 u_long tcps_sndctrl; /* control (SYN|FIN|RST) packets sent */ 191 192 u_long tcps_rcvtotal; /* total packets received */ 193 u_long tcps_rcvpack; /* packets received in sequence */ 194 u_long tcps_rcvbyte; /* bytes received in sequence */ 195 u_long tcps_rcvbadsum; /* packets received with ccksum errs */ 196 u_long tcps_rcvbadoff; /* packets received with bad offset */ 197 u_long tcps_rcvshort; /* packets received too short */ 198 u_long tcps_rcvduppack; /* duplicate-only packets received */ 199 u_long tcps_rcvdupbyte; /* duplicate-only bytes received */ 200 u_long tcps_rcvpartduppack; /* packets with some duplicate data */ 201 u_long tcps_rcvpartdupbyte; /* dup. bytes in part-dup. packets */ 202 u_long tcps_rcvoopack; /* out-of-order packets received */ 203 u_long tcps_rcvoobyte; /* out-of-order bytes received */ 204 u_long tcps_rcvpackafterwin; /* packets with data after window */ 205 u_long tcps_rcvbyteafterwin; /* bytes rcvd after window */ 206 u_long tcps_rcvafterclose; /* packets rcvd after "close" */ 207 u_long tcps_rcvwinprobe; /* rcvd window probe packets */ 208 u_long tcps_rcvdupack; /* rcvd duplicate acks */ 209 u_long tcps_rcvacktoomuch; /* rcvd acks for unsent data */ 210 u_long tcps_rcvackpack; /* rcvd ack packets */ 211 u_long tcps_rcvackbyte; /* bytes acked by rcvd acks */ 212 u_long tcps_rcvwinupd; /* rcvd window update packets */ 213 }; 214 215 #ifdef KERNEL 216 struct inpcb tcb; /* head of queue of active tcpcb's */ 217 struct tcpstat tcpstat; /* tcp statistics */ 218 struct tcpiphdr *tcp_template(); 219 struct tcpcb *tcp_close(), *tcp_drop(); 220 struct tcpcb *tcp_timers(), *tcp_disconnect(), *tcp_usrclosed(); 221 #endif 222 223 #endif /* !_NETINET_TCP_VAR_H_ */ 224