1 /* 2 * Copyright (c) 1982, 1986, 1993, 1994 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. Neither the name of the University nor the names of its contributors 14 * may be used to endorse or promote products derived from this software 15 * without specific prior written permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 * 29 * @(#)tcp_var.h 8.3 (Berkeley) 4/10/94 30 * tcp_var.h,v 1.3 1994/08/21 05:27:39 paul Exp 31 */ 32 33 #ifndef _TCP_VAR_H_ 34 #define _TCP_VAR_H_ 35 36 #include "tcpip.h" 37 #include "tcp_timer.h" 38 39 /* 40 * Tcp control block, one per tcp; fields: 41 */ 42 struct tcpcb { 43 struct tcpiphdr *seg_next; /* sequencing queue */ 44 struct tcpiphdr *seg_prev; 45 short t_state; /* state of this connection */ 46 short t_timer[TCPT_NTIMERS]; /* tcp timers */ 47 short t_rxtshift; /* log(2) of rexmt exp. backoff */ 48 short t_rxtcur; /* current retransmit value */ 49 short t_dupacks; /* consecutive dup acks recd */ 50 u_short t_maxseg; /* maximum segment size */ 51 char t_force; /* 1 if forcing out a byte */ 52 u_short t_flags; 53 #define TF_ACKNOW 0x0001 /* ack peer immediately */ 54 #define TF_DELACK 0x0002 /* ack, but try to delay it */ 55 #define TF_NODELAY 0x0004 /* don't delay packets to coalesce */ 56 #define TF_NOOPT 0x0008 /* don't use tcp options */ 57 #define TF_SENTFIN 0x0010 /* have sent FIN */ 58 #define TF_REQ_SCALE 0x0020 /* have/will request window scaling */ 59 #define TF_RCVD_SCALE 0x0040 /* other side has requested scaling */ 60 #define TF_REQ_TSTMP 0x0080 /* have/will request timestamps */ 61 #define TF_RCVD_TSTMP 0x0100 /* a timestamp was received in SYN */ 62 #define TF_SACK_PERMIT 0x0200 /* other side said I could SACK */ 63 64 /* Make it static for now */ 65 /* struct tcpiphdr *t_template; / * skeletal packet for transmit */ 66 struct tcpiphdr t_template; 67 68 struct socket *t_socket; /* back pointer to socket */ 69 /* 70 * The following fields are used as in the protocol specification. 71 * See RFC783, Dec. 1981, page 21. 72 */ 73 /* send sequence variables */ 74 tcp_seq snd_una; /* send unacknowledged */ 75 tcp_seq snd_nxt; /* send next */ 76 tcp_seq snd_up; /* send urgent pointer */ 77 tcp_seq snd_wl1; /* window update seg seq number */ 78 tcp_seq snd_wl2; /* window update seg ack number */ 79 tcp_seq iss; /* initial send sequence number */ 80 u_int32_t snd_wnd; /* send window */ 81 /* receive sequence variables */ 82 u_int32_t rcv_wnd; /* receive window */ 83 tcp_seq rcv_nxt; /* receive next */ 84 tcp_seq rcv_up; /* receive urgent pointer */ 85 tcp_seq irs; /* initial receive sequence number */ 86 /* 87 * Additional variables for this implementation. 88 */ 89 /* receive variables */ 90 tcp_seq rcv_adv; /* advertised window */ 91 /* retransmit variables */ 92 tcp_seq snd_max; /* highest sequence number sent; 93 * used to recognize retransmits 94 */ 95 /* congestion control (for slow start, source quench, retransmit after loss) */ 96 u_int32_t snd_cwnd; /* congestion-controlled window */ 97 u_int32_t snd_ssthresh; /* snd_cwnd size threshold for 98 * for slow start exponential to 99 * linear switch 100 */ 101 /* 102 * transmit timing stuff. See below for scale of srtt and rttvar. 103 * "Variance" is actually smoothed difference. 104 */ 105 short t_idle; /* inactivity time */ 106 short t_rtt; /* round trip time */ 107 tcp_seq t_rtseq; /* sequence number being timed */ 108 short t_srtt; /* smoothed round-trip time */ 109 short t_rttvar; /* variance in round-trip time */ 110 u_short t_rttmin; /* minimum rtt allowed */ 111 u_int32_t max_sndwnd; /* largest window peer has offered */ 112 113 /* out-of-band data */ 114 char t_oobflags; /* have some */ 115 char t_iobc; /* input character */ 116 #define TCPOOB_HAVEDATA 0x01 117 #define TCPOOB_HADDATA 0x02 118 short t_softerror; /* possible error not yet reported */ 119 120 /* RFC 1323 variables */ 121 u_char snd_scale; /* window scaling for send window */ 122 u_char rcv_scale; /* window scaling for recv window */ 123 u_char request_r_scale; /* pending window scaling */ 124 u_char requested_s_scale; 125 u_int32_t ts_recent; /* timestamp echo data */ 126 u_int32_t ts_recent_age; /* when last updated */ 127 tcp_seq last_ack_sent; 128 129 }; 130 131 #define sototcpcb(so) ((so)->so_tcpcb) 132 133 /* 134 * The smoothed round-trip time and estimated variance 135 * are stored as fixed point numbers scaled by the values below. 136 * For convenience, these scales are also used in smoothing the average 137 * (smoothed = (1/scale)sample + ((scale-1)/scale)smoothed). 138 * With these scales, srtt has 3 bits to the right of the binary point, 139 * and thus an "ALPHA" of 0.875. rttvar has 2 bits to the right of the 140 * binary point, and is smoothed with an ALPHA of 0.75. 141 */ 142 #define TCP_RTT_SCALE 8 /* multiplier for srtt; 3 bits frac. */ 143 #define TCP_RTT_SHIFT 3 /* shift for srtt; 3 bits frac. */ 144 #define TCP_RTTVAR_SCALE 4 /* multiplier for rttvar; 2 bits */ 145 #define TCP_RTTVAR_SHIFT 2 /* multiplier for rttvar; 2 bits */ 146 147 /* 148 * The initial retransmission should happen at rtt + 4 * rttvar. 149 * Because of the way we do the smoothing, srtt and rttvar 150 * will each average +1/2 tick of bias. When we compute 151 * the retransmit timer, we want 1/2 tick of rounding and 152 * 1 extra tick because of +-1/2 tick uncertainty in the 153 * firing of the timer. The bias will give us exactly the 154 * 1.5 tick we need. But, because the bias is 155 * statistical, we have to test that we don't drop below 156 * the minimum feasible timer (which is 2 ticks). 157 * This macro assumes that the value of TCP_RTTVAR_SCALE 158 * is the same as the multiplier for rttvar. 159 */ 160 #define TCP_REXMTVAL(tp) \ 161 (((tp)->t_srtt >> TCP_RTT_SHIFT) + (tp)->t_rttvar) 162 163 #ifdef LOG_ENABLED 164 /* 165 * TCP statistics. 166 * Many of these should be kept per connection, 167 * but that's inconvenient at the moment. 168 */ 169 struct tcpstat { 170 u_long tcps_connattempt; /* connections initiated */ 171 u_long tcps_accepts; /* connections accepted */ 172 u_long tcps_connects; /* connections established */ 173 u_long tcps_drops; /* connections dropped */ 174 u_long tcps_conndrops; /* embryonic connections dropped */ 175 u_long tcps_closed; /* conn. closed (includes drops) */ 176 u_long tcps_segstimed; /* segs where we tried to get rtt */ 177 u_long tcps_rttupdated; /* times we succeeded */ 178 u_long tcps_delack; /* delayed acks sent */ 179 u_long tcps_timeoutdrop; /* conn. dropped in rxmt timeout */ 180 u_long tcps_rexmttimeo; /* retransmit timeouts */ 181 u_long tcps_persisttimeo; /* persist timeouts */ 182 u_long tcps_keeptimeo; /* keepalive timeouts */ 183 u_long tcps_keepprobe; /* keepalive probes sent */ 184 u_long tcps_keepdrops; /* connections dropped in keepalive */ 185 186 u_long tcps_sndtotal; /* total packets sent */ 187 u_long tcps_sndpack; /* data packets sent */ 188 u_long tcps_sndbyte; /* data bytes sent */ 189 u_long tcps_sndrexmitpack; /* data packets retransmitted */ 190 u_long tcps_sndrexmitbyte; /* data bytes retransmitted */ 191 u_long tcps_sndacks; /* ack-only packets sent */ 192 u_long tcps_sndprobe; /* window probes sent */ 193 u_long tcps_sndurg; /* packets sent with URG only */ 194 u_long tcps_sndwinup; /* window update-only packets sent */ 195 u_long tcps_sndctrl; /* control (SYN|FIN|RST) packets sent */ 196 197 u_long tcps_rcvtotal; /* total packets received */ 198 u_long tcps_rcvpack; /* packets received in sequence */ 199 u_long tcps_rcvbyte; /* bytes received in sequence */ 200 u_long tcps_rcvbadsum; /* packets received with ccksum errs */ 201 u_long tcps_rcvbadoff; /* packets received with bad offset */ 202 /* u_long tcps_rcvshort; */ /* packets received too short */ 203 u_long tcps_rcvduppack; /* duplicate-only packets received */ 204 u_long tcps_rcvdupbyte; /* duplicate-only bytes received */ 205 u_long tcps_rcvpartduppack; /* packets with some duplicate data */ 206 u_long tcps_rcvpartdupbyte; /* dup. bytes in part-dup. packets */ 207 u_long tcps_rcvoopack; /* out-of-order packets received */ 208 u_long tcps_rcvoobyte; /* out-of-order bytes received */ 209 u_long tcps_rcvpackafterwin; /* packets with data after window */ 210 u_long tcps_rcvbyteafterwin; /* bytes rcvd after window */ 211 u_long tcps_rcvafterclose; /* packets rcvd after "close" */ 212 u_long tcps_rcvwinprobe; /* rcvd window probe packets */ 213 u_long tcps_rcvdupack; /* rcvd duplicate acks */ 214 u_long tcps_rcvacktoomuch; /* rcvd acks for unsent data */ 215 u_long tcps_rcvackpack; /* rcvd ack packets */ 216 u_long tcps_rcvackbyte; /* bytes acked by rcvd acks */ 217 u_long tcps_rcvwinupd; /* rcvd window update packets */ 218 /* u_long tcps_pawsdrop; */ /* segments dropped due to PAWS */ 219 u_long tcps_predack; /* times hdr predict ok for acks */ 220 u_long tcps_preddat; /* times hdr predict ok for data pkts */ 221 u_long tcps_socachemiss; /* tcp_last_so misses */ 222 u_long tcps_didnuttin; /* Times tcp_output didn't do anything XXX */ 223 }; 224 225 extern struct tcpstat tcpstat; /* tcp statistics */ 226 #endif 227 228 extern u_int32_t tcp_now; /* for RFC 1323 timestamps */ 229 230 #endif 231