Commit | Line | Data |
---|---|---|
0d115dcc | 1 | /* tcp_input.c 6.7 84/11/01 */ |
87e78f19 | 2 | |
20666ad3 JB |
3 | #include "param.h" |
4 | #include "systm.h" | |
5 | #include "mbuf.h" | |
6 | #include "protosw.h" | |
7 | #include "socket.h" | |
8 | #include "socketvar.h" | |
9 | #include "errno.h" | |
f4d55810 SL |
10 | |
11 | #include "../net/if.h" | |
c124e997 | 12 | #include "../net/route.h" |
f4d55810 | 13 | |
20666ad3 JB |
14 | #include "in.h" |
15 | #include "in_pcb.h" | |
16 | #include "in_systm.h" | |
17 | #include "ip.h" | |
18 | #include "ip_var.h" | |
19 | #include "tcp.h" | |
20 | #include "tcp_fsm.h" | |
21 | #include "tcp_seq.h" | |
22 | #include "tcp_timer.h" | |
23 | #include "tcp_var.h" | |
24 | #include "tcpip.h" | |
25 | #include "tcp_debug.h" | |
87e78f19 | 26 | |
22856bb8 | 27 | int tcpprintfs = 0; |
60b16fa9 | 28 | int tcpcksum = 1; |
4b935108 | 29 | struct tcpiphdr tcp_saveti; |
8b5a83bb | 30 | extern tcpnodelack; |
87e78f19 | 31 | |
4b935108 | 32 | struct tcpcb *tcp_newtcpcb(); |
2ff61f9d BJ |
33 | /* |
34 | * TCP input routine, follows pages 65-76 of the | |
35 | * protocol specification dated September, 1981 very closely. | |
36 | */ | |
2b4b57cd BJ |
37 | tcp_input(m0) |
38 | struct mbuf *m0; | |
87e78f19 | 39 | { |
2b4b57cd | 40 | register struct tcpiphdr *ti; |
53a5409e | 41 | struct inpcb *inp; |
2b4b57cd | 42 | register struct mbuf *m; |
8b5a83bb | 43 | struct mbuf *om = 0; |
2b4b57cd | 44 | int len, tlen, off; |
8e65fd66 | 45 | register struct tcpcb *tp = 0; |
2b4b57cd | 46 | register int tiflags; |
d52566dd | 47 | struct socket *so; |
f1b2fa5b | 48 | int todrop, acked; |
4b935108 | 49 | short ostate; |
ebcadd38 | 50 | struct in_addr laddr; |
7aa16f99 | 51 | int dropsocket = 0; |
87e78f19 BJ |
52 | |
53 | /* | |
4aed14e3 BJ |
54 | * Get IP and TCP header together in first mbuf. |
55 | * Note: IP leaves IP header in first mbuf. | |
87e78f19 | 56 | */ |
2b4b57cd | 57 | m = m0; |
20790db4 | 58 | ti = mtod(m, struct tcpiphdr *); |
4aed14e3 | 59 | if (((struct ip *)ti)->ip_hl > (sizeof (struct ip) >> 2)) |
d63599ac | 60 | ip_stripoptions((struct ip *)ti, (struct mbuf *)0); |
6703c41f BJ |
61 | if (m->m_off > MMAXOFF || m->m_len < sizeof (struct tcpiphdr)) { |
62 | if ((m = m_pullup(m, sizeof (struct tcpiphdr))) == 0) { | |
8a13b737 | 63 | tcpstat.tcps_hdrops++; |
6703c41f | 64 | return; |
8a13b737 BJ |
65 | } |
66 | ti = mtod(m, struct tcpiphdr *); | |
67 | } | |
87e78f19 | 68 | |
2b4b57cd | 69 | /* |
4aed14e3 | 70 | * Checksum extended TCP header and data. |
2b4b57cd BJ |
71 | */ |
72 | tlen = ((struct ip *)ti)->ip_len; | |
73 | len = sizeof (struct ip) + tlen; | |
60b16fa9 | 74 | if (tcpcksum) { |
2b4b57cd BJ |
75 | ti->ti_next = ti->ti_prev = 0; |
76 | ti->ti_x1 = 0; | |
ac83b17a | 77 | ti->ti_len = (u_short)tlen; |
668cc26d | 78 | ti->ti_len = htons((u_short)ti->ti_len); |
4b6b94ca | 79 | if (ti->ti_sum = in_cksum(m, len)) { |
ee954ff1 SL |
80 | if (tcpprintfs) |
81 | printf("tcp sum: src %x\n", ti->ti_src); | |
2b4b57cd | 82 | tcpstat.tcps_badsum++; |
8a13b737 | 83 | goto drop; |
87e78f19 BJ |
84 | } |
85 | } | |
86 | ||
87 | /* | |
4aed14e3 | 88 | * Check that TCP offset makes sense, |
8b5a83bb | 89 | * pull out TCP options and adjust length. |
87e78f19 | 90 | */ |
2b4b57cd | 91 | off = ti->ti_off << 2; |
4b6b94ca | 92 | if (off < sizeof (struct tcphdr) || off > tlen) { |
ee954ff1 SL |
93 | if (tcpprintfs) |
94 | printf("tcp off: src %x off %d\n", ti->ti_src, off); | |
2b4b57cd | 95 | tcpstat.tcps_badoff++; |
8a13b737 | 96 | goto drop; |
2b4b57cd | 97 | } |
1e977657 BJ |
98 | tlen -= off; |
99 | ti->ti_len = tlen; | |
8b5a83bb BJ |
100 | if (off > sizeof (struct tcphdr)) { |
101 | if ((m = m_pullup(m, sizeof (struct ip) + off)) == 0) { | |
102 | tcpstat.tcps_hdrops++; | |
01b1394e | 103 | return; |
8b5a83bb BJ |
104 | } |
105 | ti = mtod(m, struct tcpiphdr *); | |
cce93e4b | 106 | om = m_get(M_DONTWAIT, MT_DATA); |
8b5a83bb BJ |
107 | if (om == 0) |
108 | goto drop; | |
8b5a83bb BJ |
109 | om->m_len = off - sizeof (struct tcphdr); |
110 | { caddr_t op = mtod(m, caddr_t) + sizeof (struct tcpiphdr); | |
668cc26d | 111 | bcopy(op, mtod(om, caddr_t), (unsigned)om->m_len); |
8b5a83bb | 112 | m->m_len -= om->m_len; |
668cc26d SL |
113 | bcopy(op+om->m_len, op, |
114 | (unsigned)(m->m_len-sizeof (struct tcpiphdr))); | |
8b5a83bb BJ |
115 | } |
116 | } | |
2ff61f9d | 117 | tiflags = ti->ti_flags; |
2b4b57cd | 118 | |
795e0416 | 119 | /* |
1e977657 | 120 | * Drop TCP and IP headers. |
795e0416 BJ |
121 | */ |
122 | off += sizeof (struct ip); | |
123 | m->m_off += off; | |
124 | m->m_len -= off; | |
125 | ||
8a13b737 | 126 | /* |
4aed14e3 | 127 | * Convert TCP protocol specific fields to host format. |
8a13b737 BJ |
128 | */ |
129 | ti->ti_seq = ntohl(ti->ti_seq); | |
130 | ti->ti_ack = ntohl(ti->ti_ack); | |
131 | ti->ti_win = ntohs(ti->ti_win); | |
132 | ti->ti_urp = ntohs(ti->ti_urp); | |
133 | ||
2b4b57cd | 134 | /* |
8075bb0e | 135 | * Locate pcb for segment. |
2b4b57cd | 136 | */ |
2ff61f9d | 137 | inp = in_pcblookup |
ebcadd38 BJ |
138 | (&tcb, ti->ti_src, ti->ti_sport, ti->ti_dst, ti->ti_dport, |
139 | INPLOOKUP_WILDCARD); | |
2ff61f9d BJ |
140 | |
141 | /* | |
142 | * If the state is CLOSED (i.e., TCB does not exist) then | |
4aed14e3 | 143 | * all data in the incoming segment is discarded. |
2ff61f9d | 144 | */ |
22856bb8 | 145 | if (inp == 0) |
8a13b737 | 146 | goto dropwithreset; |
2ff61f9d | 147 | tp = intotcpcb(inp); |
22856bb8 | 148 | if (tp == 0) |
8a13b737 | 149 | goto dropwithreset; |
f1b2fa5b | 150 | so = inp->inp_socket; |
4b935108 BJ |
151 | if (so->so_options & SO_DEBUG) { |
152 | ostate = tp->t_state; | |
153 | tcp_saveti = *ti; | |
154 | } | |
ebf42a75 BJ |
155 | if (so->so_options & SO_ACCEPTCONN) { |
156 | so = sonewconn(so); | |
157 | if (so == 0) | |
158 | goto drop; | |
7aa16f99 SL |
159 | /* |
160 | * This is ugly, but .... | |
161 | * | |
162 | * Mark socket as temporary until we're | |
163 | * committed to keeping it. The code at | |
164 | * ``drop'' and ``dropwithreset'' check the | |
165 | * flag dropsocket to see if the temporary | |
166 | * socket created here should be discarded. | |
167 | * We mark the socket as discardable until | |
168 | * we're committed to it below in TCPS_LISTEN. | |
169 | */ | |
170 | dropsocket++; | |
ebf42a75 BJ |
171 | inp = (struct inpcb *)so->so_pcb; |
172 | inp->inp_laddr = ti->ti_dst; | |
173 | inp->inp_lport = ti->ti_dport; | |
174 | tp = intotcpcb(inp); | |
175 | tp->t_state = TCPS_LISTEN; | |
176 | } | |
87e78f19 | 177 | |
405c9168 BJ |
178 | /* |
179 | * Segment received on connection. | |
180 | * Reset idle time and keep-alive timer. | |
181 | */ | |
182 | tp->t_idle = 0; | |
183 | tp->t_timer[TCPT_KEEP] = TCPTV_KEEP; | |
184 | ||
8b5a83bb | 185 | /* |
99578149 MK |
186 | * Process options if not in LISTEN state, |
187 | * else do it below (after getting remote address). | |
8b5a83bb | 188 | */ |
99578149 MK |
189 | if (om && tp->t_state != TCPS_LISTEN) { |
190 | tcp_dooptions(tp, om, ti); | |
8b5a83bb BJ |
191 | om = 0; |
192 | } | |
193 | ||
87e78f19 | 194 | /* |
8a13b737 BJ |
195 | * Calculate amount of space in receive window, |
196 | * and then do TCP input processing. | |
87e78f19 | 197 | */ |
8a13b737 | 198 | tp->rcv_wnd = sbspace(&so->so_rcv); |
4b6b94ca BJ |
199 | if (tp->rcv_wnd < 0) |
200 | tp->rcv_wnd = 0; | |
2ff61f9d | 201 | |
87e78f19 BJ |
202 | switch (tp->t_state) { |
203 | ||
2ff61f9d BJ |
204 | /* |
205 | * If the state is LISTEN then ignore segment if it contains an RST. | |
206 | * If the segment contains an ACK then it is bad and send a RST. | |
207 | * If it does not contain a SYN then it is not interesting; drop it. | |
8a13b737 | 208 | * Otherwise initialize tp->rcv_nxt, and tp->irs, select an initial |
2ff61f9d | 209 | * tp->iss, and send a segment: |
8a13b737 | 210 | * <SEQ=ISS><ACK=RCV_NXT><CTL=SYN,ACK> |
2ff61f9d BJ |
211 | * Also initialize tp->snd_nxt to tp->iss+1 and tp->snd_una to tp->iss. |
212 | * Fill in remote peer address fields if not previously specified. | |
213 | * Enter SYN_RECEIVED state, and process any other fields of this | |
4aed14e3 | 214 | * segment in this state. |
2ff61f9d | 215 | */ |
8075bb0e | 216 | case TCPS_LISTEN: { |
789d2a39 | 217 | struct mbuf *am; |
8075bb0e BJ |
218 | register struct sockaddr_in *sin; |
219 | ||
2ff61f9d BJ |
220 | if (tiflags & TH_RST) |
221 | goto drop; | |
22856bb8 | 222 | if (tiflags & TH_ACK) |
8a13b737 | 223 | goto dropwithreset; |
22856bb8 | 224 | if ((tiflags & TH_SYN) == 0) |
2ff61f9d | 225 | goto drop; |
789d2a39 SL |
226 | am = m_get(M_DONTWAIT, MT_SONAME); |
227 | if (am == NULL) | |
228 | goto drop; | |
229 | am->m_len = sizeof (struct sockaddr_in); | |
a8d3bf7f | 230 | sin = mtod(am, struct sockaddr_in *); |
8075bb0e BJ |
231 | sin->sin_family = AF_INET; |
232 | sin->sin_addr = ti->ti_src; | |
233 | sin->sin_port = ti->ti_sport; | |
ebcadd38 | 234 | laddr = inp->inp_laddr; |
789d2a39 | 235 | if (inp->inp_laddr.s_addr == INADDR_ANY) |
ebcadd38 | 236 | inp->inp_laddr = ti->ti_dst; |
a8d3bf7f | 237 | if (in_pcbconnect(inp, am)) { |
ebcadd38 | 238 | inp->inp_laddr = laddr; |
5a1f132a | 239 | (void) m_free(am); |
4aed14e3 | 240 | goto drop; |
ebcadd38 | 241 | } |
5a1f132a | 242 | (void) m_free(am); |
4aed14e3 BJ |
243 | tp->t_template = tcp_template(tp); |
244 | if (tp->t_template == 0) { | |
245 | in_pcbdisconnect(inp); | |
a4f7ea71 | 246 | dropsocket = 0; /* socket is already gone */ |
ebcadd38 | 247 | inp->inp_laddr = laddr; |
93f92b1d | 248 | tp = 0; |
4aed14e3 BJ |
249 | goto drop; |
250 | } | |
99578149 MK |
251 | if (om) { |
252 | tcp_dooptions(tp, om, ti); | |
253 | om = 0; | |
254 | } | |
8a13b737 | 255 | tp->iss = tcp_iss; tcp_iss += TCP_ISSINCR/2; |
2ff61f9d | 256 | tp->irs = ti->ti_seq; |
8a13b737 BJ |
257 | tcp_sendseqinit(tp); |
258 | tcp_rcvseqinit(tp); | |
2ff61f9d | 259 | tp->t_state = TCPS_SYN_RECEIVED; |
4aed14e3 | 260 | tp->t_timer[TCPT_KEEP] = TCPTV_KEEP; |
7aa16f99 | 261 | dropsocket = 0; /* committed to socket */ |
8a13b737 | 262 | goto trimthenstep6; |
8075bb0e | 263 | } |
87e78f19 | 264 | |
2ff61f9d BJ |
265 | /* |
266 | * If the state is SYN_SENT: | |
267 | * if seg contains an ACK, but not for our SYN, drop the input. | |
268 | * if seg contains a RST, then drop the connection. | |
269 | * if seg does not contain SYN, then drop it. | |
270 | * Otherwise this is an acceptable SYN segment | |
271 | * initialize tp->rcv_nxt and tp->irs | |
272 | * if seg contains ack then advance tp->snd_una | |
273 | * if SYN has been acked change to ESTABLISHED else SYN_RCVD state | |
274 | * arrange for segment to be acked (eventually) | |
275 | * continue processing rest of data/controls, beginning with URG | |
276 | */ | |
277 | case TCPS_SYN_SENT: | |
278 | if ((tiflags & TH_ACK) && | |
22856bb8 BJ |
279 | /* this should be SEQ_LT; is SEQ_LEQ for BBN vax TCP only */ |
280 | (SEQ_LT(ti->ti_ack, tp->iss) || | |
4b6b94ca | 281 | SEQ_GT(ti->ti_ack, tp->snd_max))) |
8a13b737 | 282 | goto dropwithreset; |
2ff61f9d | 283 | if (tiflags & TH_RST) { |
0e3936fa SL |
284 | if (tiflags & TH_ACK) |
285 | tp = tcp_drop(tp, ECONNREFUSED); | |
2ff61f9d | 286 | goto drop; |
87e78f19 | 287 | } |
2ff61f9d BJ |
288 | if ((tiflags & TH_SYN) == 0) |
289 | goto drop; | |
4b6b94ca | 290 | tp->snd_una = ti->ti_ack; |
b8977237 BJ |
291 | if (SEQ_LT(tp->snd_nxt, tp->snd_una)) |
292 | tp->snd_nxt = tp->snd_una; | |
4aed14e3 | 293 | tp->t_timer[TCPT_REXMT] = 0; |
2ff61f9d | 294 | tp->irs = ti->ti_seq; |
8a13b737 BJ |
295 | tcp_rcvseqinit(tp); |
296 | tp->t_flags |= TF_ACKNOW; | |
405c9168 | 297 | if (SEQ_GT(tp->snd_una, tp->iss)) { |
4aed14e3 | 298 | soisconnected(so); |
2ff61f9d | 299 | tp->t_state = TCPS_ESTABLISHED; |
99578149 | 300 | tp->t_maxseg = MIN(tp->t_maxseg, tcp_mss(tp)); |
405c9168 BJ |
301 | (void) tcp_reass(tp, (struct tcpiphdr *)0); |
302 | } else | |
8a13b737 BJ |
303 | tp->t_state = TCPS_SYN_RECEIVED; |
304 | goto trimthenstep6; | |
305 | ||
306 | trimthenstep6: | |
307 | /* | |
4b6b94ca | 308 | * Advance ti->ti_seq to correspond to first data byte. |
8a13b737 BJ |
309 | * If data, trim to stay within window, |
310 | * dropping FIN if necessary. | |
311 | */ | |
4b6b94ca | 312 | ti->ti_seq++; |
8a13b737 BJ |
313 | if (ti->ti_len > tp->rcv_wnd) { |
314 | todrop = ti->ti_len - tp->rcv_wnd; | |
315 | m_adj(m, -todrop); | |
316 | ti->ti_len = tp->rcv_wnd; | |
317 | ti->ti_flags &= ~TH_FIN; | |
87e78f19 | 318 | } |
e832edbc | 319 | tp->snd_wl1 = ti->ti_seq - 1; |
8a13b737 | 320 | goto step6; |
2ff61f9d | 321 | } |
87e78f19 | 322 | |
ed6315dd MK |
323 | /* |
324 | * If data is received on a connection after the | |
325 | * user processes are gone, then RST the other end. | |
326 | */ | |
327 | if ((so->so_state & SS_NOFDREF) && tp->t_state > TCPS_CLOSE_WAIT && | |
328 | ti->ti_len) { | |
329 | tp = tcp_close(tp); | |
330 | goto dropwithreset; | |
331 | } | |
332 | ||
2ff61f9d BJ |
333 | /* |
334 | * States other than LISTEN or SYN_SENT. | |
335 | * First check that at least some bytes of segment are within | |
336 | * receive window. | |
337 | */ | |
338 | if (tp->rcv_wnd == 0) { | |
339 | /* | |
340 | * If window is closed can only take segments at | |
4b6b94ca | 341 | * window edge, and have to drop data and PUSH from |
2ff61f9d BJ |
342 | * incoming segments. |
343 | */ | |
22856bb8 | 344 | if (tp->rcv_nxt != ti->ti_seq) |
2ff61f9d | 345 | goto dropafterack; |
8a13b737 | 346 | if (ti->ti_len > 0) { |
fd5dc5f0 | 347 | m_adj(m, ti->ti_len); |
8a13b737 BJ |
348 | ti->ti_len = 0; |
349 | ti->ti_flags &= ~(TH_PUSH|TH_FIN); | |
87e78f19 | 350 | } |
2ff61f9d BJ |
351 | } else { |
352 | /* | |
4b6b94ca | 353 | * If segment begins before rcv_nxt, drop leading |
2ff61f9d BJ |
354 | * data (and SYN); if nothing left, just ack. |
355 | */ | |
fd5dc5f0 BJ |
356 | todrop = tp->rcv_nxt - ti->ti_seq; |
357 | if (todrop > 0) { | |
8a13b737 | 358 | if (tiflags & TH_SYN) { |
22856bb8 | 359 | tiflags &= ~TH_SYN; |
fd5dc5f0 | 360 | ti->ti_flags &= ~TH_SYN; |
8a13b737 BJ |
361 | ti->ti_seq++; |
362 | if (ti->ti_urp > 1) | |
363 | ti->ti_urp--; | |
364 | else | |
365 | tiflags &= ~TH_URG; | |
366 | todrop--; | |
367 | } | |
1e977657 BJ |
368 | if (todrop > ti->ti_len || |
369 | todrop == ti->ti_len && (tiflags&TH_FIN) == 0) | |
2ff61f9d BJ |
370 | goto dropafterack; |
371 | m_adj(m, todrop); | |
372 | ti->ti_seq += todrop; | |
373 | ti->ti_len -= todrop; | |
8a13b737 BJ |
374 | if (ti->ti_urp > todrop) |
375 | ti->ti_urp -= todrop; | |
376 | else { | |
377 | tiflags &= ~TH_URG; | |
fd5dc5f0 BJ |
378 | ti->ti_flags &= ~TH_URG; |
379 | ti->ti_urp = 0; | |
8a13b737 | 380 | } |
2ff61f9d BJ |
381 | } |
382 | /* | |
383 | * If segment ends after window, drop trailing data | |
8a13b737 | 384 | * (and PUSH and FIN); if nothing left, just ACK. |
2ff61f9d | 385 | */ |
fd5dc5f0 BJ |
386 | todrop = (ti->ti_seq+ti->ti_len) - (tp->rcv_nxt+tp->rcv_wnd); |
387 | if (todrop > 0) { | |
1e977657 | 388 | if (todrop >= ti->ti_len) |
2ff61f9d BJ |
389 | goto dropafterack; |
390 | m_adj(m, -todrop); | |
391 | ti->ti_len -= todrop; | |
8a13b737 | 392 | ti->ti_flags &= ~(TH_PUSH|TH_FIN); |
87e78f19 | 393 | } |
87e78f19 | 394 | } |
87e78f19 | 395 | |
87e78f19 | 396 | /* |
2ff61f9d BJ |
397 | * If the RST bit is set examine the state: |
398 | * SYN_RECEIVED STATE: | |
399 | * If passive open, return to LISTEN state. | |
400 | * If active open, inform user that connection was refused. | |
401 | * ESTABLISHED, FIN_WAIT_1, FIN_WAIT2, CLOSE_WAIT STATES: | |
402 | * Inform user that connection was reset, and close tcb. | |
403 | * CLOSING, LAST_ACK, TIME_WAIT STATES | |
404 | * Close the tcb. | |
87e78f19 | 405 | */ |
2ff61f9d | 406 | if (tiflags&TH_RST) switch (tp->t_state) { |
4b935108 | 407 | |
2ff61f9d | 408 | case TCPS_SYN_RECEIVED: |
0e3936fa | 409 | tp = tcp_drop(tp, ECONNREFUSED); |
2ff61f9d BJ |
410 | goto drop; |
411 | ||
412 | case TCPS_ESTABLISHED: | |
413 | case TCPS_FIN_WAIT_1: | |
414 | case TCPS_FIN_WAIT_2: | |
415 | case TCPS_CLOSE_WAIT: | |
0e3936fa | 416 | tp = tcp_drop(tp, ECONNRESET); |
2ff61f9d BJ |
417 | goto drop; |
418 | ||
419 | case TCPS_CLOSING: | |
420 | case TCPS_LAST_ACK: | |
421 | case TCPS_TIME_WAIT: | |
0e3936fa | 422 | tp = tcp_close(tp); |
2ff61f9d | 423 | goto drop; |
87e78f19 | 424 | } |
87e78f19 BJ |
425 | |
426 | /* | |
2ff61f9d BJ |
427 | * If a SYN is in the window, then this is an |
428 | * error and we send an RST and drop the connection. | |
429 | */ | |
430 | if (tiflags & TH_SYN) { | |
0e3936fa | 431 | tp = tcp_drop(tp, ECONNRESET); |
8a13b737 | 432 | goto dropwithreset; |
2ff61f9d BJ |
433 | } |
434 | ||
435 | /* | |
436 | * If the ACK bit is off we drop the segment and return. | |
437 | */ | |
8a13b737 | 438 | if ((tiflags & TH_ACK) == 0) |
2ff61f9d BJ |
439 | goto drop; |
440 | ||
441 | /* | |
442 | * Ack processing. | |
87e78f19 | 443 | */ |
87e78f19 BJ |
444 | switch (tp->t_state) { |
445 | ||
2ff61f9d BJ |
446 | /* |
447 | * In SYN_RECEIVED state if the ack ACKs our SYN then enter | |
448 | * ESTABLISHED state and continue processing, othewise | |
449 | * send an RST. | |
450 | */ | |
451 | case TCPS_SYN_RECEIVED: | |
8a13b737 | 452 | if (SEQ_GT(tp->snd_una, ti->ti_ack) || |
4b6b94ca | 453 | SEQ_GT(ti->ti_ack, tp->snd_max)) |
8a13b737 | 454 | goto dropwithreset; |
4aed14e3 | 455 | tp->snd_una++; /* SYN acked */ |
b8977237 BJ |
456 | if (SEQ_LT(tp->snd_nxt, tp->snd_una)) |
457 | tp->snd_nxt = tp->snd_una; | |
4aed14e3 | 458 | tp->t_timer[TCPT_REXMT] = 0; |
8a13b737 BJ |
459 | soisconnected(so); |
460 | tp->t_state = TCPS_ESTABLISHED; | |
99578149 | 461 | tp->t_maxseg = MIN(tp->t_maxseg, tcp_mss(tp)); |
405c9168 | 462 | (void) tcp_reass(tp, (struct tcpiphdr *)0); |
4aed14e3 | 463 | tp->snd_wl1 = ti->ti_seq - 1; |
8a13b737 | 464 | /* fall into ... */ |
87e78f19 | 465 | |
2ff61f9d BJ |
466 | /* |
467 | * In ESTABLISHED state: drop duplicate ACKs; ACK out of range | |
468 | * ACKs. If the ack is in the range | |
4b6b94ca | 469 | * tp->snd_una < ti->ti_ack <= tp->snd_max |
2ff61f9d BJ |
470 | * then advance tp->snd_una to ti->ti_ack and drop |
471 | * data from the retransmission queue. If this ACK reflects | |
472 | * more up to date window information we update our window information. | |
473 | */ | |
474 | case TCPS_ESTABLISHED: | |
475 | case TCPS_FIN_WAIT_1: | |
476 | case TCPS_FIN_WAIT_2: | |
477 | case TCPS_CLOSE_WAIT: | |
478 | case TCPS_CLOSING: | |
4aed14e3 BJ |
479 | case TCPS_LAST_ACK: |
480 | case TCPS_TIME_WAIT: | |
8a13b737 BJ |
481 | #define ourfinisacked (acked > 0) |
482 | ||
4aed14e3 | 483 | if (SEQ_LEQ(ti->ti_ack, tp->snd_una)) |
2ff61f9d | 484 | break; |
22856bb8 | 485 | if (SEQ_GT(ti->ti_ack, tp->snd_max)) |
2ff61f9d | 486 | goto dropafterack; |
8a13b737 | 487 | acked = ti->ti_ack - tp->snd_una; |
dd020fc8 BJ |
488 | |
489 | /* | |
490 | * If transmit timer is running and timed sequence | |
491 | * number was acked, update smoothed round trip time. | |
492 | */ | |
493 | if (tp->t_rtt && SEQ_GT(ti->ti_ack, tp->t_rtseq)) { | |
494 | if (tp->t_srtt == 0) | |
495 | tp->t_srtt = tp->t_rtt; | |
496 | else | |
497 | tp->t_srtt = | |
498 | tcp_alpha * tp->t_srtt + | |
499 | (1 - tcp_alpha) * tp->t_rtt; | |
dd020fc8 BJ |
500 | tp->t_rtt = 0; |
501 | } | |
502 | ||
6703c41f | 503 | if (ti->ti_ack == tp->snd_max) |
4aed14e3 | 504 | tp->t_timer[TCPT_REXMT] = 0; |
6703c41f | 505 | else { |
4aed14e3 BJ |
506 | TCPT_RANGESET(tp->t_timer[TCPT_REXMT], |
507 | tcp_beta * tp->t_srtt, TCPTV_MIN, TCPTV_MAX); | |
22856bb8 | 508 | tp->t_rxtshift = 0; |
8a13b737 | 509 | } |
6703c41f | 510 | if (acked > so->so_snd.sb_cc) { |
6703c41f | 511 | tp->snd_wnd -= so->so_snd.sb_cc; |
26e96dd8 | 512 | sbdrop(&so->so_snd, so->so_snd.sb_cc); |
6703c41f | 513 | } else { |
668cc26d | 514 | sbdrop(&so->so_snd, acked); |
6703c41f BJ |
515 | tp->snd_wnd -= acked; |
516 | acked = 0; | |
517 | } | |
5744ed2b | 518 | if ((so->so_snd.sb_flags & SB_WAIT) || so->so_snd.sb_sel) |
22856bb8 | 519 | sowwakeup(so); |
4b6b94ca | 520 | tp->snd_una = ti->ti_ack; |
b8977237 BJ |
521 | if (SEQ_LT(tp->snd_nxt, tp->snd_una)) |
522 | tp->snd_nxt = tp->snd_una; | |
405c9168 | 523 | |
87e78f19 BJ |
524 | switch (tp->t_state) { |
525 | ||
2ff61f9d BJ |
526 | /* |
527 | * In FIN_WAIT_1 STATE in addition to the processing | |
528 | * for the ESTABLISHED state if our FIN is now acknowledged | |
8a13b737 | 529 | * then enter FIN_WAIT_2. |
2ff61f9d BJ |
530 | */ |
531 | case TCPS_FIN_WAIT_1: | |
fdae4427 BJ |
532 | if (ourfinisacked) { |
533 | /* | |
534 | * If we can't receive any more | |
535 | * data, then closing user can proceed. | |
536 | */ | |
537 | if (so->so_state & SS_CANTRCVMORE) | |
538 | soisdisconnected(so); | |
8a13b737 | 539 | tp->t_state = TCPS_FIN_WAIT_2; |
a4f7ea71 MK |
540 | /* |
541 | * This is contrary to the specification, | |
542 | * but if we haven't gotten our FIN in | |
543 | * 5 minutes, it's not forthcoming. | |
544 | */ | |
0d115dcc | 545 | tp->t_timer[TCPT_2MSL] = 5 * 60 * PR_SLOWHZ; |
fdae4427 | 546 | } |
87e78f19 BJ |
547 | break; |
548 | ||
2ff61f9d BJ |
549 | /* |
550 | * In CLOSING STATE in addition to the processing for | |
551 | * the ESTABLISHED state if the ACK acknowledges our FIN | |
552 | * then enter the TIME-WAIT state, otherwise ignore | |
553 | * the segment. | |
554 | */ | |
555 | case TCPS_CLOSING: | |
4aed14e3 | 556 | if (ourfinisacked) { |
2ff61f9d | 557 | tp->t_state = TCPS_TIME_WAIT; |
4aed14e3 BJ |
558 | tcp_canceltimers(tp); |
559 | tp->t_timer[TCPT_2MSL] = 2 * TCPTV_MSL; | |
560 | soisdisconnected(so); | |
561 | } | |
562 | break; | |
87e78f19 | 563 | |
2ff61f9d | 564 | /* |
8a13b737 BJ |
565 | * The only thing that can arrive in LAST_ACK state |
566 | * is an acknowledgment of our FIN. If our FIN is now | |
567 | * acknowledged, delete the TCB, enter the closed state | |
568 | * and return. | |
2ff61f9d BJ |
569 | */ |
570 | case TCPS_LAST_ACK: | |
0e3936fa SL |
571 | if (ourfinisacked) |
572 | tp = tcp_close(tp); | |
2ff61f9d | 573 | goto drop; |
87e78f19 | 574 | |
2ff61f9d BJ |
575 | /* |
576 | * In TIME_WAIT state the only thing that should arrive | |
577 | * is a retransmission of the remote FIN. Acknowledge | |
578 | * it and restart the finack timer. | |
579 | */ | |
580 | case TCPS_TIME_WAIT: | |
405c9168 | 581 | tp->t_timer[TCPT_2MSL] = 2 * TCPTV_MSL; |
2ff61f9d | 582 | goto dropafterack; |
87e78f19 | 583 | } |
8a13b737 BJ |
584 | #undef ourfinisacked |
585 | } | |
87e78f19 | 586 | |
2ff61f9d | 587 | step6: |
4aed14e3 BJ |
588 | /* |
589 | * Update window information. | |
590 | */ | |
22856bb8 | 591 | if (SEQ_LT(tp->snd_wl1, ti->ti_seq) || tp->snd_wl1 == ti->ti_seq && |
8e65fd66 | 592 | (SEQ_LT(tp->snd_wl2, ti->ti_ack) || |
22856bb8 | 593 | tp->snd_wl2 == ti->ti_ack && ti->ti_win > tp->snd_wnd)) { |
4aed14e3 BJ |
594 | tp->snd_wnd = ti->ti_win; |
595 | tp->snd_wl1 = ti->ti_seq; | |
596 | tp->snd_wl2 = ti->ti_ack; | |
a8d3bf7f | 597 | if (tp->snd_wnd != 0) |
4aed14e3 BJ |
598 | tp->t_timer[TCPT_PERSIST] = 0; |
599 | } | |
4aed14e3 | 600 | |
2ff61f9d | 601 | /* |
b2db9217 | 602 | * Process segments with URG. |
2ff61f9d | 603 | */ |
9c811062 BJ |
604 | if ((tiflags & TH_URG) && ti->ti_urp && |
605 | TCPS_HAVERCVDFIN(tp->t_state) == 0) { | |
f4be5024 | 606 | /* |
a5d9c993 SL |
607 | * This is a kludge, but if we receive accept |
608 | * random urgent pointers, we'll crash in | |
609 | * soreceive. It's hard to imagine someone | |
610 | * actually wanting to send this much urgent data. | |
f4be5024 | 611 | */ |
a4f7ea71 | 612 | if (ti->ti_urp > tp->rcv_wnd + 1) { /* XXX */ |
f4be5024 SL |
613 | ti->ti_urp = 0; /* XXX */ |
614 | tiflags &= ~TH_URG; /* XXX */ | |
615 | ti->ti_flags &= ~TH_URG; /* XXX */ | |
a5d9c993 | 616 | goto badurp; /* XXX */ |
f4be5024 | 617 | } |
b2db9217 BJ |
618 | /* |
619 | * If this segment advances the known urgent pointer, | |
620 | * then mark the data stream. This should not happen | |
621 | * in CLOSE_WAIT, CLOSING, LAST_ACK or TIME_WAIT STATES since | |
622 | * a FIN has been received from the remote side. | |
623 | * In these states we ignore the URG. | |
624 | */ | |
625 | if (SEQ_GT(ti->ti_seq+ti->ti_urp, tp->rcv_up)) { | |
626 | tp->rcv_up = ti->ti_seq + ti->ti_urp; | |
627 | so->so_oobmark = so->so_rcv.sb_cc + | |
628 | (tp->rcv_up - tp->rcv_nxt) - 1; | |
629 | if (so->so_oobmark == 0) | |
630 | so->so_state |= SS_RCVATMARK; | |
77a4e3ca | 631 | sohasoutofband(so); |
b2db9217 BJ |
632 | tp->t_oobflags &= ~TCPOOB_HAVEDATA; |
633 | } | |
634 | /* | |
635 | * Remove out of band data so doesn't get presented to user. | |
636 | * This can happen independent of advancing the URG pointer, | |
637 | * but if two URG's are pending at once, some out-of-band | |
638 | * data may creep in... ick. | |
639 | */ | |
ebf42a75 | 640 | if (ti->ti_urp <= ti->ti_len) |
b2db9217 | 641 | tcp_pulloutofband(so, ti); |
5e74df82 | 642 | } |
a5d9c993 | 643 | badurp: /* XXX */ |
87e78f19 BJ |
644 | |
645 | /* | |
2ff61f9d BJ |
646 | * Process the segment text, merging it into the TCP sequencing queue, |
647 | * and arranging for acknowledgment of receipt if necessary. | |
648 | * This process logically involves adjusting tp->rcv_wnd as data | |
649 | * is presented to the user (this happens in tcp_usrreq.c, | |
650 | * case PRU_RCVD). If a FIN has already been received on this | |
651 | * connection then we just ignore the text. | |
87e78f19 | 652 | */ |
e832edbc BJ |
653 | if ((ti->ti_len || (tiflags&TH_FIN)) && |
654 | TCPS_HAVERCVDFIN(tp->t_state) == 0) { | |
2ff61f9d | 655 | tiflags = tcp_reass(tp, ti); |
8b5a83bb BJ |
656 | if (tcpnodelack == 0) |
657 | tp->t_flags |= TF_DELACK; | |
658 | else | |
659 | tp->t_flags |= TF_ACKNOW; | |
4aed14e3 | 660 | } else { |
2b4b57cd | 661 | m_freem(m); |
e832edbc | 662 | tiflags &= ~TH_FIN; |
4aed14e3 | 663 | } |
87e78f19 BJ |
664 | |
665 | /* | |
e832edbc BJ |
666 | * If FIN is received ACK the FIN and let the user know |
667 | * that the connection is closing. | |
87e78f19 | 668 | */ |
e832edbc | 669 | if (tiflags & TH_FIN) { |
4aed14e3 BJ |
670 | if (TCPS_HAVERCVDFIN(tp->t_state) == 0) { |
671 | socantrcvmore(so); | |
672 | tp->t_flags |= TF_ACKNOW; | |
673 | tp->rcv_nxt++; | |
674 | } | |
2ff61f9d | 675 | switch (tp->t_state) { |
87e78f19 | 676 | |
2ff61f9d BJ |
677 | /* |
678 | * In SYN_RECEIVED and ESTABLISHED STATES | |
679 | * enter the CLOSE_WAIT state. | |
53a5409e | 680 | */ |
2ff61f9d BJ |
681 | case TCPS_SYN_RECEIVED: |
682 | case TCPS_ESTABLISHED: | |
683 | tp->t_state = TCPS_CLOSE_WAIT; | |
684 | break; | |
53a5409e | 685 | |
2ff61f9d | 686 | /* |
8a13b737 BJ |
687 | * If still in FIN_WAIT_1 STATE FIN has not been acked so |
688 | * enter the CLOSING state. | |
53a5409e | 689 | */ |
2ff61f9d | 690 | case TCPS_FIN_WAIT_1: |
8a13b737 | 691 | tp->t_state = TCPS_CLOSING; |
2ff61f9d | 692 | break; |
87e78f19 | 693 | |
2ff61f9d BJ |
694 | /* |
695 | * In FIN_WAIT_2 state enter the TIME_WAIT state, | |
696 | * starting the time-wait timer, turning off the other | |
697 | * standard timers. | |
698 | */ | |
699 | case TCPS_FIN_WAIT_2: | |
4aed14e3 | 700 | tp->t_state = TCPS_TIME_WAIT; |
a6503abf | 701 | tcp_canceltimers(tp); |
405c9168 | 702 | tp->t_timer[TCPT_2MSL] = 2 * TCPTV_MSL; |
4aed14e3 | 703 | soisdisconnected(so); |
2ff61f9d BJ |
704 | break; |
705 | ||
53a5409e | 706 | /* |
2ff61f9d | 707 | * In TIME_WAIT state restart the 2 MSL time_wait timer. |
53a5409e | 708 | */ |
2ff61f9d | 709 | case TCPS_TIME_WAIT: |
405c9168 | 710 | tp->t_timer[TCPT_2MSL] = 2 * TCPTV_MSL; |
2ff61f9d | 711 | break; |
8a13b737 | 712 | } |
87e78f19 | 713 | } |
4b935108 BJ |
714 | if (so->so_options & SO_DEBUG) |
715 | tcp_trace(TA_INPUT, ostate, tp, &tcp_saveti, 0); | |
8a13b737 BJ |
716 | |
717 | /* | |
718 | * Return any desired output. | |
719 | */ | |
668cc26d | 720 | (void) tcp_output(tp); |
2ff61f9d | 721 | return; |
8a13b737 | 722 | |
2ff61f9d | 723 | dropafterack: |
8a13b737 | 724 | /* |
1e977657 BJ |
725 | * Generate an ACK dropping incoming segment if it occupies |
726 | * sequence space, where the ACK reflects our state. | |
8a13b737 | 727 | */ |
1e977657 BJ |
728 | if ((tiflags&TH_RST) || |
729 | tlen == 0 && (tiflags&(TH_SYN|TH_FIN)) == 0) | |
8a13b737 | 730 | goto drop; |
f3cdd721 BJ |
731 | if (tp->t_inpcb->inp_socket->so_options & SO_DEBUG) |
732 | tcp_trace(TA_RESPOND, ostate, tp, &tcp_saveti, 0); | |
8e65fd66 | 733 | tcp_respond(tp, ti, tp->rcv_nxt, tp->snd_nxt, TH_ACK); |
4b6b94ca | 734 | return; |
8a13b737 BJ |
735 | |
736 | dropwithreset: | |
f37c1c84 | 737 | if (om) { |
668cc26d | 738 | (void) m_free(om); |
f37c1c84 SL |
739 | om = 0; |
740 | } | |
8a13b737 | 741 | /* |
4aed14e3 | 742 | * Generate a RST, dropping incoming segment. |
8a13b737 BJ |
743 | * Make ACK acceptable to originator of segment. |
744 | */ | |
745 | if (tiflags & TH_RST) | |
746 | goto drop; | |
747 | if (tiflags & TH_ACK) | |
8e65fd66 | 748 | tcp_respond(tp, ti, (tcp_seq)0, ti->ti_ack, TH_RST); |
8a13b737 BJ |
749 | else { |
750 | if (tiflags & TH_SYN) | |
751 | ti->ti_len++; | |
1e977657 BJ |
752 | tcp_respond(tp, ti, ti->ti_seq+ti->ti_len, (tcp_seq)0, |
753 | TH_RST|TH_ACK); | |
8a13b737 | 754 | } |
7aa16f99 SL |
755 | /* destroy temporarily created socket */ |
756 | if (dropsocket) | |
757 | (void) soabort(so); | |
4b6b94ca | 758 | return; |
8a13b737 | 759 | |
2ff61f9d | 760 | drop: |
01b1394e SL |
761 | if (om) |
762 | (void) m_free(om); | |
8a13b737 BJ |
763 | /* |
764 | * Drop space held by incoming segment and return. | |
765 | */ | |
f3cdd721 BJ |
766 | if (tp && (tp->t_inpcb->inp_socket->so_options & SO_DEBUG)) |
767 | tcp_trace(TA_DROP, ostate, tp, &tcp_saveti, 0); | |
2ff61f9d | 768 | m_freem(m); |
7aa16f99 SL |
769 | /* destroy temporarily created socket */ |
770 | if (dropsocket) | |
771 | (void) soabort(so); | |
4b935108 | 772 | return; |
2ff61f9d BJ |
773 | } |
774 | ||
99578149 | 775 | tcp_dooptions(tp, om, ti) |
8b5a83bb BJ |
776 | struct tcpcb *tp; |
777 | struct mbuf *om; | |
99578149 | 778 | struct tcpiphdr *ti; |
5e74df82 | 779 | { |
8b5a83bb BJ |
780 | register u_char *cp; |
781 | int opt, optlen, cnt; | |
782 | ||
783 | cp = mtod(om, u_char *); | |
784 | cnt = om->m_len; | |
785 | for (; cnt > 0; cnt -= optlen, cp += optlen) { | |
786 | opt = cp[0]; | |
787 | if (opt == TCPOPT_EOL) | |
788 | break; | |
789 | if (opt == TCPOPT_NOP) | |
790 | optlen = 1; | |
357b20fc | 791 | else { |
8b5a83bb | 792 | optlen = cp[1]; |
357b20fc SL |
793 | if (optlen <= 0) |
794 | break; | |
795 | } | |
8b5a83bb BJ |
796 | switch (opt) { |
797 | ||
798 | default: | |
799 | break; | |
800 | ||
801 | case TCPOPT_MAXSEG: | |
802 | if (optlen != 4) | |
803 | continue; | |
99578149 MK |
804 | if (!(ti->ti_flags & TH_SYN)) |
805 | continue; | |
8b5a83bb | 806 | tp->t_maxseg = *(u_short *)(cp + 2); |
668cc26d | 807 | tp->t_maxseg = ntohs((u_short)tp->t_maxseg); |
99578149 | 808 | tp->t_maxseg = MIN(tp->t_maxseg, tcp_mss(tp)); |
8b5a83bb | 809 | break; |
8b5a83bb | 810 | } |
5e74df82 | 811 | } |
668cc26d | 812 | (void) m_free(om); |
5e74df82 BJ |
813 | } |
814 | ||
b2db9217 BJ |
815 | /* |
816 | * Pull out of band byte out of a segment so | |
817 | * it doesn't appear in the user's data queue. | |
818 | * It is still reflected in the segment length for | |
819 | * sequencing purposes. | |
820 | */ | |
821 | tcp_pulloutofband(so, ti) | |
822 | struct socket *so; | |
823 | struct tcpiphdr *ti; | |
824 | { | |
825 | register struct mbuf *m; | |
1acff8ec | 826 | int cnt = ti->ti_urp - 1; |
b2db9217 BJ |
827 | |
828 | m = dtom(ti); | |
829 | while (cnt >= 0) { | |
830 | if (m->m_len > cnt) { | |
831 | char *cp = mtod(m, caddr_t) + cnt; | |
832 | struct tcpcb *tp = sototcpcb(so); | |
833 | ||
834 | tp->t_iobc = *cp; | |
835 | tp->t_oobflags |= TCPOOB_HAVEDATA; | |
668cc26d | 836 | bcopy(cp+1, cp, (unsigned)(m->m_len - cnt - 1)); |
b2db9217 BJ |
837 | m->m_len--; |
838 | return; | |
839 | } | |
840 | cnt -= m->m_len; | |
841 | m = m->m_next; | |
842 | if (m == 0) | |
843 | break; | |
844 | } | |
845 | panic("tcp_pulloutofband"); | |
846 | } | |
847 | ||
2ff61f9d BJ |
848 | /* |
849 | * Insert segment ti into reassembly queue of tcp with | |
850 | * control block tp. Return TH_FIN if reassembly now includes | |
851 | * a segment with FIN. | |
852 | */ | |
f1b2fa5b | 853 | tcp_reass(tp, ti) |
2ff61f9d BJ |
854 | register struct tcpcb *tp; |
855 | register struct tcpiphdr *ti; | |
2ff61f9d BJ |
856 | { |
857 | register struct tcpiphdr *q; | |
8a13b737 | 858 | struct socket *so = tp->t_inpcb->inp_socket; |
e832edbc BJ |
859 | struct mbuf *m; |
860 | int flags; | |
2ff61f9d BJ |
861 | |
862 | /* | |
405c9168 BJ |
863 | * Call with ti==0 after become established to |
864 | * force pre-ESTABLISHED data up to user socket. | |
2ff61f9d | 865 | */ |
405c9168 | 866 | if (ti == 0) |
2ff61f9d | 867 | goto present; |
87e78f19 | 868 | |
2ff61f9d BJ |
869 | /* |
870 | * Find a segment which begins after this one does. | |
871 | */ | |
872 | for (q = tp->seg_next; q != (struct tcpiphdr *)tp; | |
873 | q = (struct tcpiphdr *)q->ti_next) | |
874 | if (SEQ_GT(q->ti_seq, ti->ti_seq)) | |
875 | break; | |
876 | ||
877 | /* | |
878 | * If there is a preceding segment, it may provide some of | |
879 | * our data already. If so, drop the data from the incoming | |
880 | * segment. If it provides all of our data, drop us. | |
881 | */ | |
882 | if ((struct tcpiphdr *)q->ti_prev != (struct tcpiphdr *)tp) { | |
883 | register int i; | |
fd5dc5f0 | 884 | q = (struct tcpiphdr *)q->ti_prev; |
2ff61f9d BJ |
885 | /* conversion to int (in i) handles seq wraparound */ |
886 | i = q->ti_seq + q->ti_len - ti->ti_seq; | |
887 | if (i > 0) { | |
2b4b57cd | 888 | if (i >= ti->ti_len) |
2ff61f9d | 889 | goto drop; |
4ab1a5c3 | 890 | m_adj(dtom(ti), i); |
2b4b57cd | 891 | ti->ti_len -= i; |
2ff61f9d | 892 | ti->ti_seq += i; |
53a5409e | 893 | } |
2ff61f9d BJ |
894 | q = (struct tcpiphdr *)(q->ti_next); |
895 | } | |
87e78f19 | 896 | |
2ff61f9d BJ |
897 | /* |
898 | * While we overlap succeeding segments trim them or, | |
899 | * if they are completely covered, dequeue them. | |
900 | */ | |
fd5dc5f0 | 901 | while (q != (struct tcpiphdr *)tp) { |
2ff61f9d | 902 | register int i = (ti->ti_seq + ti->ti_len) - q->ti_seq; |
fd5dc5f0 BJ |
903 | if (i <= 0) |
904 | break; | |
2ff61f9d | 905 | if (i < q->ti_len) { |
fd5dc5f0 | 906 | q->ti_seq += i; |
2ff61f9d BJ |
907 | q->ti_len -= i; |
908 | m_adj(dtom(q), i); | |
909 | break; | |
ac5e71a1 | 910 | } |
2ff61f9d | 911 | q = (struct tcpiphdr *)q->ti_next; |
473a17a5 | 912 | m = dtom(q->ti_prev); |
2ff61f9d | 913 | remque(q->ti_prev); |
473a17a5 | 914 | m_freem(m); |
2ff61f9d | 915 | } |
87e78f19 | 916 | |
2ff61f9d BJ |
917 | /* |
918 | * Stick new segment in its place. | |
919 | */ | |
920 | insque(ti, q->ti_prev); | |
2ff61f9d | 921 | |
2ff61f9d BJ |
922 | present: |
923 | /* | |
4aed14e3 BJ |
924 | * Present data to user, advancing rcv_nxt through |
925 | * completed sequence space. | |
2ff61f9d | 926 | */ |
e832edbc | 927 | if (TCPS_HAVERCVDSYN(tp->t_state) == 0) |
4aed14e3 | 928 | return (0); |
2b4b57cd | 929 | ti = tp->seg_next; |
e832edbc BJ |
930 | if (ti == (struct tcpiphdr *)tp || ti->ti_seq != tp->rcv_nxt) |
931 | return (0); | |
932 | if (tp->t_state == TCPS_SYN_RECEIVED && ti->ti_len) | |
933 | return (0); | |
934 | do { | |
4aed14e3 BJ |
935 | tp->rcv_nxt += ti->ti_len; |
936 | flags = ti->ti_flags & TH_FIN; | |
2b4b57cd | 937 | remque(ti); |
e832edbc | 938 | m = dtom(ti); |
2b4b57cd | 939 | ti = (struct tcpiphdr *)ti->ti_next; |
e832edbc | 940 | if (so->so_state & SS_CANTRCVMORE) |
668cc26d | 941 | m_freem(m); |
789d2a39 | 942 | else |
e832edbc BJ |
943 | sbappend(&so->so_rcv, m); |
944 | } while (ti != (struct tcpiphdr *)tp && ti->ti_seq == tp->rcv_nxt); | |
945 | sorwakeup(so); | |
2ff61f9d BJ |
946 | return (flags); |
947 | drop: | |
948 | m_freem(dtom(ti)); | |
e832edbc | 949 | return (0); |
d52566dd | 950 | } |
99578149 MK |
951 | |
952 | /* | |
953 | * Determine a reasonable value for maxseg size. | |
954 | * If the route is known, use one that can be handled | |
955 | * on the given interface without forcing IP to fragment. | |
956 | * If bigger than a page (CLSIZE), round down to nearest pagesize | |
957 | * to utilize pagesize mbufs. | |
958 | * If interface pointer is unavailable, or the destination isn't local, | |
959 | * use a conservative size (512 or the default IP max size), | |
960 | * as we can't discover anything about intervening gateways or networks. | |
961 | * | |
962 | * This is ugly, and doesn't belong at this level, but has to happen somehow. | |
963 | */ | |
964 | tcp_mss(tp) | |
965 | register struct tcpcb *tp; | |
966 | { | |
967 | struct route *ro; | |
968 | struct ifnet *ifp; | |
969 | int mss; | |
970 | struct inpcb *inp; | |
971 | ||
972 | inp = tp->t_inpcb; | |
973 | ro = &inp->inp_route; | |
974 | if ((ro->ro_rt == (struct rtentry *)0) || | |
975 | (ifp = ro->ro_rt->rt_ifp) == (struct ifnet *)0) { | |
976 | /* No route yet, so try to acquire one */ | |
977 | if (inp->inp_faddr.s_addr != INADDR_ANY) { | |
978 | ro->ro_dst.sa_family = AF_INET; | |
979 | ((struct sockaddr_in *) &ro->ro_dst)->sin_addr = | |
980 | inp->inp_faddr; | |
981 | rtalloc(ro); | |
982 | } | |
983 | if ((ro->ro_rt == 0) || (ifp = ro->ro_rt->rt_ifp) == 0) | |
0d115dcc | 984 | return (TCP_MSS); |
99578149 MK |
985 | } |
986 | ||
987 | mss = ifp->if_mtu - sizeof(struct tcpiphdr); | |
988 | #if (CLBYTES & (CLBYTES - 1)) == 0 | |
989 | if (mss > CLBYTES) | |
990 | mss &= ~(CLBYTES-1); | |
991 | #else | |
992 | if (mss > CLBYTES) | |
993 | mss = mss / CLBYTES * CLBYTES; | |
994 | #endif | |
995 | if (in_localaddr(tp->t_inpcb->inp_faddr)) | |
996 | return(mss); | |
0d115dcc | 997 | return (MIN(mss, TCP_MSS)); |
99578149 | 998 | } |