Commit | Line | Data |
---|---|---|
4ab1a5c3 | 1 | /* tcp_input.c 1.71 82/06/30 */ |
87e78f19 BJ |
2 | |
3 | #include "../h/param.h" | |
4 | #include "../h/systm.h" | |
dad64fdf | 5 | #include "../h/mbuf.h" |
8a13b737 | 6 | #include "../h/protosw.h" |
dad64fdf | 7 | #include "../h/socket.h" |
d52566dd | 8 | #include "../h/socketvar.h" |
8a13b737 | 9 | #include "../net/in.h" |
c124e997 | 10 | #include "../net/route.h" |
8a13b737 BJ |
11 | #include "../net/in_pcb.h" |
12 | #include "../net/in_systm.h" | |
13 | #include "../net/if.h" | |
d52566dd | 14 | #include "../net/ip.h" |
eb44bfb2 | 15 | #include "../net/ip_var.h" |
d52566dd BJ |
16 | #include "../net/tcp.h" |
17 | #include "../net/tcp_fsm.h" | |
8a13b737 BJ |
18 | #include "../net/tcp_seq.h" |
19 | #include "../net/tcp_timer.h" | |
d52566dd | 20 | #include "../net/tcp_var.h" |
8a13b737 | 21 | #include "../net/tcpip.h" |
4b935108 | 22 | #include "../net/tcp_debug.h" |
c47a5909 | 23 | #include <errno.h> |
87e78f19 | 24 | |
22856bb8 | 25 | int tcpprintfs = 0; |
60b16fa9 | 26 | int tcpcksum = 1; |
4aed14e3 | 27 | struct sockaddr_in tcp_in = { AF_INET }; |
4b935108 | 28 | struct tcpiphdr tcp_saveti; |
8b5a83bb | 29 | extern tcpnodelack; |
87e78f19 | 30 | |
4b935108 | 31 | struct tcpcb *tcp_newtcpcb(); |
2ff61f9d BJ |
32 | /* |
33 | * TCP input routine, follows pages 65-76 of the | |
34 | * protocol specification dated September, 1981 very closely. | |
35 | */ | |
2b4b57cd BJ |
36 | tcp_input(m0) |
37 | struct mbuf *m0; | |
87e78f19 | 38 | { |
2b4b57cd | 39 | register struct tcpiphdr *ti; |
53a5409e | 40 | struct inpcb *inp; |
2b4b57cd | 41 | register struct mbuf *m; |
8b5a83bb | 42 | struct mbuf *om = 0; |
2b4b57cd | 43 | int len, tlen, off; |
8e65fd66 | 44 | register struct tcpcb *tp = 0; |
2b4b57cd | 45 | register int tiflags; |
d52566dd | 46 | struct socket *so; |
f1b2fa5b | 47 | int todrop, acked; |
4b935108 | 48 | short ostate; |
ebcadd38 | 49 | struct in_addr laddr; |
87e78f19 BJ |
50 | |
51 | /* | |
4aed14e3 BJ |
52 | * Get IP and TCP header together in first mbuf. |
53 | * Note: IP leaves IP header in first mbuf. | |
87e78f19 | 54 | */ |
2b4b57cd | 55 | m = m0; |
20790db4 | 56 | ti = mtod(m, struct tcpiphdr *); |
4aed14e3 | 57 | if (((struct ip *)ti)->ip_hl > (sizeof (struct ip) >> 2)) |
d63599ac | 58 | ip_stripoptions((struct ip *)ti, (struct mbuf *)0); |
6703c41f BJ |
59 | if (m->m_off > MMAXOFF || m->m_len < sizeof (struct tcpiphdr)) { |
60 | if ((m = m_pullup(m, sizeof (struct tcpiphdr))) == 0) { | |
8a13b737 | 61 | tcpstat.tcps_hdrops++; |
6703c41f | 62 | return; |
8a13b737 BJ |
63 | } |
64 | ti = mtod(m, struct tcpiphdr *); | |
65 | } | |
87e78f19 | 66 | |
2b4b57cd | 67 | /* |
4aed14e3 | 68 | * Checksum extended TCP header and data. |
2b4b57cd BJ |
69 | */ |
70 | tlen = ((struct ip *)ti)->ip_len; | |
71 | len = sizeof (struct ip) + tlen; | |
60b16fa9 | 72 | if (tcpcksum) { |
2b4b57cd BJ |
73 | ti->ti_next = ti->ti_prev = 0; |
74 | ti->ti_x1 = 0; | |
ac83b17a | 75 | ti->ti_len = (u_short)tlen; |
93f92b1d | 76 | #if vax || pdp11 |
668cc26d | 77 | ti->ti_len = htons((u_short)ti->ti_len); |
ac83b17a | 78 | #endif |
4b6b94ca | 79 | if (ti->ti_sum = in_cksum(m, len)) { |
2b4b57cd | 80 | tcpstat.tcps_badsum++; |
1e977657 BJ |
81 | if (tcpprintfs) |
82 | printf("tcp cksum %x\n", ti->ti_sum); | |
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) { |
2b4b57cd | 93 | tcpstat.tcps_badoff++; |
8a13b737 | 94 | goto drop; |
2b4b57cd | 95 | } |
1e977657 BJ |
96 | tlen -= off; |
97 | ti->ti_len = tlen; | |
8b5a83bb BJ |
98 | if (off > sizeof (struct tcphdr)) { |
99 | if ((m = m_pullup(m, sizeof (struct ip) + off)) == 0) { | |
100 | tcpstat.tcps_hdrops++; | |
101 | goto drop; | |
102 | } | |
103 | ti = mtod(m, struct tcpiphdr *); | |
104 | om = m_get(M_DONTWAIT); | |
105 | if (om == 0) | |
106 | goto drop; | |
107 | om->m_off = MMINOFF; | |
108 | om->m_len = off - sizeof (struct tcphdr); | |
109 | { caddr_t op = mtod(m, caddr_t) + sizeof (struct tcpiphdr); | |
668cc26d | 110 | bcopy(op, mtod(om, caddr_t), (unsigned)om->m_len); |
8b5a83bb | 111 | m->m_len -= om->m_len; |
668cc26d SL |
112 | bcopy(op+om->m_len, op, |
113 | (unsigned)(m->m_len-sizeof (struct tcpiphdr))); | |
8b5a83bb BJ |
114 | } |
115 | } | |
2ff61f9d | 116 | tiflags = ti->ti_flags; |
2b4b57cd | 117 | |
795e0416 | 118 | /* |
1e977657 | 119 | * Drop TCP and IP headers. |
795e0416 BJ |
120 | */ |
121 | off += sizeof (struct ip); | |
122 | m->m_off += off; | |
123 | m->m_len -= off; | |
124 | ||
93f92b1d | 125 | #if vax || pdp11 |
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); | |
4b6b94ca | 133 | #endif |
8a13b737 | 134 | |
2b4b57cd | 135 | /* |
1aa87517 BJ |
136 | * Locate pcb for segment. On match, update the local |
137 | * address stored in the block to reflect anchoring. | |
2b4b57cd | 138 | */ |
2ff61f9d | 139 | inp = in_pcblookup |
ebcadd38 BJ |
140 | (&tcb, ti->ti_src, ti->ti_sport, ti->ti_dst, ti->ti_dport, |
141 | INPLOOKUP_WILDCARD); | |
2ff61f9d BJ |
142 | |
143 | /* | |
144 | * If the state is CLOSED (i.e., TCB does not exist) then | |
4aed14e3 | 145 | * all data in the incoming segment is discarded. |
2ff61f9d | 146 | */ |
22856bb8 | 147 | if (inp == 0) |
8a13b737 | 148 | goto dropwithreset; |
2ff61f9d | 149 | tp = intotcpcb(inp); |
22856bb8 | 150 | if (tp == 0) |
8a13b737 | 151 | goto dropwithreset; |
f1b2fa5b | 152 | so = inp->inp_socket; |
4b935108 BJ |
153 | if (so->so_options & SO_DEBUG) { |
154 | ostate = tp->t_state; | |
155 | tcp_saveti = *ti; | |
156 | } | |
87e78f19 | 157 | |
405c9168 BJ |
158 | /* |
159 | * Segment received on connection. | |
160 | * Reset idle time and keep-alive timer. | |
161 | */ | |
162 | tp->t_idle = 0; | |
163 | tp->t_timer[TCPT_KEEP] = TCPTV_KEEP; | |
164 | ||
8b5a83bb BJ |
165 | /* |
166 | * Process options. | |
167 | */ | |
168 | if (om) { | |
169 | tcp_dooptions(tp, om); | |
170 | om = 0; | |
171 | } | |
172 | ||
87e78f19 | 173 | /* |
8a13b737 BJ |
174 | * Calculate amount of space in receive window, |
175 | * and then do TCP input processing. | |
87e78f19 | 176 | */ |
8a13b737 | 177 | tp->rcv_wnd = sbspace(&so->so_rcv); |
4b6b94ca BJ |
178 | if (tp->rcv_wnd < 0) |
179 | tp->rcv_wnd = 0; | |
2ff61f9d | 180 | |
87e78f19 BJ |
181 | switch (tp->t_state) { |
182 | ||
2ff61f9d BJ |
183 | /* |
184 | * If the state is LISTEN then ignore segment if it contains an RST. | |
185 | * If the segment contains an ACK then it is bad and send a RST. | |
186 | * If it does not contain a SYN then it is not interesting; drop it. | |
8a13b737 | 187 | * Otherwise initialize tp->rcv_nxt, and tp->irs, select an initial |
2ff61f9d | 188 | * tp->iss, and send a segment: |
8a13b737 | 189 | * <SEQ=ISS><ACK=RCV_NXT><CTL=SYN,ACK> |
2ff61f9d BJ |
190 | * Also initialize tp->snd_nxt to tp->iss+1 and tp->snd_una to tp->iss. |
191 | * Fill in remote peer address fields if not previously specified. | |
192 | * Enter SYN_RECEIVED state, and process any other fields of this | |
4aed14e3 | 193 | * segment in this state. |
2ff61f9d BJ |
194 | */ |
195 | case TCPS_LISTEN: | |
196 | if (tiflags & TH_RST) | |
197 | goto drop; | |
22856bb8 | 198 | if (tiflags & TH_ACK) |
8a13b737 | 199 | goto dropwithreset; |
22856bb8 | 200 | if ((tiflags & TH_SYN) == 0) |
2ff61f9d | 201 | goto drop; |
4aed14e3 BJ |
202 | tcp_in.sin_addr = ti->ti_src; |
203 | tcp_in.sin_port = ti->ti_sport; | |
ebcadd38 BJ |
204 | laddr = inp->inp_laddr; |
205 | if (inp->inp_laddr.s_addr == 0) | |
206 | inp->inp_laddr = ti->ti_dst; | |
668cc26d | 207 | if (in_pcbconnect(inp, (struct sockaddr_in *)&tcp_in)) { |
ebcadd38 | 208 | inp->inp_laddr = laddr; |
4aed14e3 | 209 | goto drop; |
ebcadd38 | 210 | } |
4aed14e3 BJ |
211 | tp->t_template = tcp_template(tp); |
212 | if (tp->t_template == 0) { | |
213 | in_pcbdisconnect(inp); | |
ebcadd38 | 214 | inp->inp_laddr = laddr; |
93f92b1d | 215 | tp = 0; |
4aed14e3 BJ |
216 | goto drop; |
217 | } | |
8a13b737 | 218 | tp->iss = tcp_iss; tcp_iss += TCP_ISSINCR/2; |
2ff61f9d | 219 | tp->irs = ti->ti_seq; |
8a13b737 BJ |
220 | tcp_sendseqinit(tp); |
221 | tcp_rcvseqinit(tp); | |
2ff61f9d | 222 | tp->t_state = TCPS_SYN_RECEIVED; |
4aed14e3 | 223 | tp->t_timer[TCPT_KEEP] = TCPTV_KEEP; |
8a13b737 | 224 | goto trimthenstep6; |
87e78f19 | 225 | |
2ff61f9d BJ |
226 | /* |
227 | * If the state is SYN_SENT: | |
228 | * if seg contains an ACK, but not for our SYN, drop the input. | |
229 | * if seg contains a RST, then drop the connection. | |
230 | * if seg does not contain SYN, then drop it. | |
231 | * Otherwise this is an acceptable SYN segment | |
232 | * initialize tp->rcv_nxt and tp->irs | |
233 | * if seg contains ack then advance tp->snd_una | |
234 | * if SYN has been acked change to ESTABLISHED else SYN_RCVD state | |
235 | * arrange for segment to be acked (eventually) | |
236 | * continue processing rest of data/controls, beginning with URG | |
237 | */ | |
238 | case TCPS_SYN_SENT: | |
239 | if ((tiflags & TH_ACK) && | |
22856bb8 BJ |
240 | /* this should be SEQ_LT; is SEQ_LEQ for BBN vax TCP only */ |
241 | (SEQ_LT(ti->ti_ack, tp->iss) || | |
4b6b94ca | 242 | SEQ_GT(ti->ti_ack, tp->snd_max))) |
8a13b737 | 243 | goto dropwithreset; |
2ff61f9d | 244 | if (tiflags & TH_RST) { |
93f92b1d | 245 | if (tiflags & TH_ACK) { |
4b935108 | 246 | tcp_drop(tp, ECONNREFUSED); |
93f92b1d BJ |
247 | tp = 0; |
248 | } | |
2ff61f9d | 249 | goto drop; |
87e78f19 | 250 | } |
2ff61f9d BJ |
251 | if ((tiflags & TH_SYN) == 0) |
252 | goto drop; | |
4b6b94ca | 253 | tp->snd_una = ti->ti_ack; |
b8977237 BJ |
254 | if (SEQ_LT(tp->snd_nxt, tp->snd_una)) |
255 | tp->snd_nxt = tp->snd_una; | |
4aed14e3 | 256 | tp->t_timer[TCPT_REXMT] = 0; |
2ff61f9d | 257 | tp->irs = ti->ti_seq; |
8a13b737 BJ |
258 | tcp_rcvseqinit(tp); |
259 | tp->t_flags |= TF_ACKNOW; | |
405c9168 | 260 | if (SEQ_GT(tp->snd_una, tp->iss)) { |
8e65fd66 BJ |
261 | if (so->so_options & SO_ACCEPTCONN) |
262 | so->so_state |= SS_CONNAWAITING; | |
4aed14e3 | 263 | soisconnected(so); |
2ff61f9d | 264 | tp->t_state = TCPS_ESTABLISHED; |
405c9168 BJ |
265 | (void) tcp_reass(tp, (struct tcpiphdr *)0); |
266 | } else | |
8a13b737 BJ |
267 | tp->t_state = TCPS_SYN_RECEIVED; |
268 | goto trimthenstep6; | |
269 | ||
270 | trimthenstep6: | |
271 | /* | |
4b6b94ca | 272 | * Advance ti->ti_seq to correspond to first data byte. |
8a13b737 BJ |
273 | * If data, trim to stay within window, |
274 | * dropping FIN if necessary. | |
275 | */ | |
4b6b94ca | 276 | ti->ti_seq++; |
8a13b737 BJ |
277 | if (ti->ti_len > tp->rcv_wnd) { |
278 | todrop = ti->ti_len - tp->rcv_wnd; | |
279 | m_adj(m, -todrop); | |
280 | ti->ti_len = tp->rcv_wnd; | |
281 | ti->ti_flags &= ~TH_FIN; | |
87e78f19 | 282 | } |
e832edbc | 283 | tp->snd_wl1 = ti->ti_seq - 1; |
8a13b737 | 284 | goto step6; |
2ff61f9d | 285 | } |
87e78f19 | 286 | |
2ff61f9d BJ |
287 | /* |
288 | * States other than LISTEN or SYN_SENT. | |
289 | * First check that at least some bytes of segment are within | |
290 | * receive window. | |
291 | */ | |
292 | if (tp->rcv_wnd == 0) { | |
293 | /* | |
294 | * If window is closed can only take segments at | |
4b6b94ca | 295 | * window edge, and have to drop data and PUSH from |
2ff61f9d BJ |
296 | * incoming segments. |
297 | */ | |
22856bb8 | 298 | if (tp->rcv_nxt != ti->ti_seq) |
2ff61f9d | 299 | goto dropafterack; |
8a13b737 | 300 | if (ti->ti_len > 0) { |
fd5dc5f0 | 301 | m_adj(m, ti->ti_len); |
8a13b737 BJ |
302 | ti->ti_len = 0; |
303 | ti->ti_flags &= ~(TH_PUSH|TH_FIN); | |
87e78f19 | 304 | } |
2ff61f9d BJ |
305 | } else { |
306 | /* | |
4b6b94ca | 307 | * If segment begins before rcv_nxt, drop leading |
2ff61f9d BJ |
308 | * data (and SYN); if nothing left, just ack. |
309 | */ | |
fd5dc5f0 BJ |
310 | todrop = tp->rcv_nxt - ti->ti_seq; |
311 | if (todrop > 0) { | |
8a13b737 | 312 | if (tiflags & TH_SYN) { |
22856bb8 | 313 | tiflags &= ~TH_SYN; |
fd5dc5f0 | 314 | ti->ti_flags &= ~TH_SYN; |
8a13b737 BJ |
315 | ti->ti_seq++; |
316 | if (ti->ti_urp > 1) | |
317 | ti->ti_urp--; | |
318 | else | |
319 | tiflags &= ~TH_URG; | |
320 | todrop--; | |
321 | } | |
1e977657 BJ |
322 | if (todrop > ti->ti_len || |
323 | todrop == ti->ti_len && (tiflags&TH_FIN) == 0) | |
2ff61f9d BJ |
324 | goto dropafterack; |
325 | m_adj(m, todrop); | |
326 | ti->ti_seq += todrop; | |
327 | ti->ti_len -= todrop; | |
8a13b737 BJ |
328 | if (ti->ti_urp > todrop) |
329 | ti->ti_urp -= todrop; | |
330 | else { | |
331 | tiflags &= ~TH_URG; | |
fd5dc5f0 BJ |
332 | ti->ti_flags &= ~TH_URG; |
333 | ti->ti_urp = 0; | |
8a13b737 | 334 | } |
2ff61f9d BJ |
335 | } |
336 | /* | |
337 | * If segment ends after window, drop trailing data | |
8a13b737 | 338 | * (and PUSH and FIN); if nothing left, just ACK. |
2ff61f9d | 339 | */ |
fd5dc5f0 BJ |
340 | todrop = (ti->ti_seq+ti->ti_len) - (tp->rcv_nxt+tp->rcv_wnd); |
341 | if (todrop > 0) { | |
1e977657 | 342 | if (todrop >= ti->ti_len) |
2ff61f9d BJ |
343 | goto dropafterack; |
344 | m_adj(m, -todrop); | |
345 | ti->ti_len -= todrop; | |
8a13b737 | 346 | ti->ti_flags &= ~(TH_PUSH|TH_FIN); |
87e78f19 | 347 | } |
87e78f19 | 348 | } |
87e78f19 | 349 | |
dd020fc8 BJ |
350 | /* |
351 | * If a segment is received on a connection after the | |
352 | * user processes are gone, then RST the other end. | |
353 | */ | |
354 | if (so->so_state & SS_USERGONE) { | |
355 | tcp_close(tp); | |
9d0b428a | 356 | tp = 0; |
dd020fc8 BJ |
357 | goto dropwithreset; |
358 | } | |
359 | ||
87e78f19 | 360 | /* |
2ff61f9d BJ |
361 | * If the RST bit is set examine the state: |
362 | * SYN_RECEIVED STATE: | |
363 | * If passive open, return to LISTEN state. | |
364 | * If active open, inform user that connection was refused. | |
365 | * ESTABLISHED, FIN_WAIT_1, FIN_WAIT2, CLOSE_WAIT STATES: | |
366 | * Inform user that connection was reset, and close tcb. | |
367 | * CLOSING, LAST_ACK, TIME_WAIT STATES | |
368 | * Close the tcb. | |
87e78f19 | 369 | */ |
2ff61f9d | 370 | if (tiflags&TH_RST) switch (tp->t_state) { |
4b935108 | 371 | |
2ff61f9d BJ |
372 | case TCPS_SYN_RECEIVED: |
373 | if (inp->inp_socket->so_options & SO_ACCEPTCONN) { | |
4b935108 | 374 | /* a miniature tcp_close, but invisible to user */ |
4aed14e3 | 375 | (void) m_free(dtom(tp->t_template)); |
4b935108 BJ |
376 | (void) m_free(dtom(tp)); |
377 | inp->inp_ppcb = 0; | |
378 | tp = tcp_newtcpcb(inp); | |
379 | tp->t_state = TCPS_LISTEN; | |
ebcadd38 BJ |
380 | inp->inp_faddr.s_addr = 0; |
381 | inp->inp_fport = 0; | |
382 | inp->inp_laddr.s_addr = 0; /* not quite right */ | |
93f92b1d | 383 | tp = 0; |
2ff61f9d BJ |
384 | goto drop; |
385 | } | |
8a13b737 | 386 | tcp_drop(tp, ECONNREFUSED); |
93f92b1d | 387 | tp = 0; |
2ff61f9d BJ |
388 | goto drop; |
389 | ||
390 | case TCPS_ESTABLISHED: | |
391 | case TCPS_FIN_WAIT_1: | |
392 | case TCPS_FIN_WAIT_2: | |
393 | case TCPS_CLOSE_WAIT: | |
394 | tcp_drop(tp, ECONNRESET); | |
93f92b1d | 395 | tp = 0; |
2ff61f9d BJ |
396 | goto drop; |
397 | ||
398 | case TCPS_CLOSING: | |
399 | case TCPS_LAST_ACK: | |
400 | case TCPS_TIME_WAIT: | |
401 | tcp_close(tp); | |
93f92b1d | 402 | tp = 0; |
2ff61f9d | 403 | goto drop; |
87e78f19 | 404 | } |
87e78f19 BJ |
405 | |
406 | /* | |
2ff61f9d BJ |
407 | * If a SYN is in the window, then this is an |
408 | * error and we send an RST and drop the connection. | |
409 | */ | |
410 | if (tiflags & TH_SYN) { | |
4b6b94ca | 411 | tcp_drop(tp, ECONNRESET); |
9d0b428a | 412 | tp = 0; |
8a13b737 | 413 | goto dropwithreset; |
2ff61f9d BJ |
414 | } |
415 | ||
416 | /* | |
417 | * If the ACK bit is off we drop the segment and return. | |
418 | */ | |
8a13b737 | 419 | if ((tiflags & TH_ACK) == 0) |
2ff61f9d BJ |
420 | goto drop; |
421 | ||
422 | /* | |
423 | * Ack processing. | |
87e78f19 | 424 | */ |
87e78f19 BJ |
425 | switch (tp->t_state) { |
426 | ||
2ff61f9d BJ |
427 | /* |
428 | * In SYN_RECEIVED state if the ack ACKs our SYN then enter | |
429 | * ESTABLISHED state and continue processing, othewise | |
430 | * send an RST. | |
431 | */ | |
432 | case TCPS_SYN_RECEIVED: | |
8a13b737 | 433 | if (SEQ_GT(tp->snd_una, ti->ti_ack) || |
4b6b94ca | 434 | SEQ_GT(ti->ti_ack, tp->snd_max)) |
8a13b737 | 435 | goto dropwithreset; |
4aed14e3 | 436 | tp->snd_una++; /* SYN acked */ |
b8977237 BJ |
437 | if (SEQ_LT(tp->snd_nxt, tp->snd_una)) |
438 | tp->snd_nxt = tp->snd_una; | |
4aed14e3 | 439 | tp->t_timer[TCPT_REXMT] = 0; |
8e65fd66 BJ |
440 | if (so->so_options & SO_ACCEPTCONN) |
441 | so->so_state |= SS_CONNAWAITING; | |
8a13b737 BJ |
442 | soisconnected(so); |
443 | tp->t_state = TCPS_ESTABLISHED; | |
405c9168 | 444 | (void) tcp_reass(tp, (struct tcpiphdr *)0); |
4aed14e3 | 445 | tp->snd_wl1 = ti->ti_seq - 1; |
8a13b737 | 446 | /* fall into ... */ |
87e78f19 | 447 | |
2ff61f9d BJ |
448 | /* |
449 | * In ESTABLISHED state: drop duplicate ACKs; ACK out of range | |
450 | * ACKs. If the ack is in the range | |
4b6b94ca | 451 | * tp->snd_una < ti->ti_ack <= tp->snd_max |
2ff61f9d BJ |
452 | * then advance tp->snd_una to ti->ti_ack and drop |
453 | * data from the retransmission queue. If this ACK reflects | |
454 | * more up to date window information we update our window information. | |
455 | */ | |
456 | case TCPS_ESTABLISHED: | |
457 | case TCPS_FIN_WAIT_1: | |
458 | case TCPS_FIN_WAIT_2: | |
459 | case TCPS_CLOSE_WAIT: | |
460 | case TCPS_CLOSING: | |
4aed14e3 BJ |
461 | case TCPS_LAST_ACK: |
462 | case TCPS_TIME_WAIT: | |
8a13b737 BJ |
463 | #define ourfinisacked (acked > 0) |
464 | ||
4aed14e3 | 465 | if (SEQ_LEQ(ti->ti_ack, tp->snd_una)) |
2ff61f9d | 466 | break; |
22856bb8 | 467 | if (SEQ_GT(ti->ti_ack, tp->snd_max)) |
2ff61f9d | 468 | goto dropafterack; |
8a13b737 | 469 | acked = ti->ti_ack - tp->snd_una; |
dd020fc8 BJ |
470 | |
471 | /* | |
472 | * If transmit timer is running and timed sequence | |
473 | * number was acked, update smoothed round trip time. | |
474 | */ | |
475 | if (tp->t_rtt && SEQ_GT(ti->ti_ack, tp->t_rtseq)) { | |
476 | if (tp->t_srtt == 0) | |
477 | tp->t_srtt = tp->t_rtt; | |
478 | else | |
479 | tp->t_srtt = | |
480 | tcp_alpha * tp->t_srtt + | |
481 | (1 - tcp_alpha) * tp->t_rtt; | |
482 | /* printf("rtt %d srtt*100 now %d\n", tp->t_rtt, (int)(tp->t_srtt*100)); */ | |
483 | tp->t_rtt = 0; | |
484 | } | |
485 | ||
6703c41f | 486 | if (ti->ti_ack == tp->snd_max) |
4aed14e3 | 487 | tp->t_timer[TCPT_REXMT] = 0; |
6703c41f | 488 | else { |
4aed14e3 BJ |
489 | TCPT_RANGESET(tp->t_timer[TCPT_REXMT], |
490 | tcp_beta * tp->t_srtt, TCPTV_MIN, TCPTV_MAX); | |
dd020fc8 | 491 | tp->t_rtt = 1; |
22856bb8 | 492 | tp->t_rxtshift = 0; |
8a13b737 | 493 | } |
6703c41f BJ |
494 | if (acked > so->so_snd.sb_cc) { |
495 | sbdrop(&so->so_snd, so->so_snd.sb_cc); | |
496 | tp->snd_wnd -= so->so_snd.sb_cc; | |
497 | } else { | |
668cc26d | 498 | sbdrop(&so->so_snd, acked); |
6703c41f BJ |
499 | tp->snd_wnd -= acked; |
500 | acked = 0; | |
501 | } | |
5744ed2b | 502 | if ((so->so_snd.sb_flags & SB_WAIT) || so->so_snd.sb_sel) |
22856bb8 | 503 | sowwakeup(so); |
4b6b94ca | 504 | tp->snd_una = ti->ti_ack; |
b8977237 BJ |
505 | if (SEQ_LT(tp->snd_nxt, tp->snd_una)) |
506 | tp->snd_nxt = tp->snd_una; | |
405c9168 | 507 | |
87e78f19 BJ |
508 | switch (tp->t_state) { |
509 | ||
2ff61f9d BJ |
510 | /* |
511 | * In FIN_WAIT_1 STATE in addition to the processing | |
512 | * for the ESTABLISHED state if our FIN is now acknowledged | |
8a13b737 | 513 | * then enter FIN_WAIT_2. |
2ff61f9d BJ |
514 | */ |
515 | case TCPS_FIN_WAIT_1: | |
fdae4427 BJ |
516 | if (ourfinisacked) { |
517 | /* | |
518 | * If we can't receive any more | |
519 | * data, then closing user can proceed. | |
520 | */ | |
521 | if (so->so_state & SS_CANTRCVMORE) | |
522 | soisdisconnected(so); | |
8a13b737 | 523 | tp->t_state = TCPS_FIN_WAIT_2; |
fdae4427 | 524 | } |
87e78f19 BJ |
525 | break; |
526 | ||
2ff61f9d BJ |
527 | /* |
528 | * In CLOSING STATE in addition to the processing for | |
529 | * the ESTABLISHED state if the ACK acknowledges our FIN | |
530 | * then enter the TIME-WAIT state, otherwise ignore | |
531 | * the segment. | |
532 | */ | |
533 | case TCPS_CLOSING: | |
4aed14e3 | 534 | if (ourfinisacked) { |
2ff61f9d | 535 | tp->t_state = TCPS_TIME_WAIT; |
4aed14e3 BJ |
536 | tcp_canceltimers(tp); |
537 | tp->t_timer[TCPT_2MSL] = 2 * TCPTV_MSL; | |
538 | soisdisconnected(so); | |
539 | } | |
540 | break; | |
87e78f19 | 541 | |
2ff61f9d | 542 | /* |
8a13b737 BJ |
543 | * The only thing that can arrive in LAST_ACK state |
544 | * is an acknowledgment of our FIN. If our FIN is now | |
545 | * acknowledged, delete the TCB, enter the closed state | |
546 | * and return. | |
2ff61f9d BJ |
547 | */ |
548 | case TCPS_LAST_ACK: | |
93f92b1d | 549 | if (ourfinisacked) { |
2ff61f9d | 550 | tcp_close(tp); |
93f92b1d BJ |
551 | tp = 0; |
552 | } | |
2ff61f9d | 553 | goto drop; |
87e78f19 | 554 | |
2ff61f9d BJ |
555 | /* |
556 | * In TIME_WAIT state the only thing that should arrive | |
557 | * is a retransmission of the remote FIN. Acknowledge | |
558 | * it and restart the finack timer. | |
559 | */ | |
560 | case TCPS_TIME_WAIT: | |
405c9168 | 561 | tp->t_timer[TCPT_2MSL] = 2 * TCPTV_MSL; |
2ff61f9d | 562 | goto dropafterack; |
87e78f19 | 563 | } |
8a13b737 BJ |
564 | #undef ourfinisacked |
565 | } | |
87e78f19 | 566 | |
2ff61f9d | 567 | step6: |
4aed14e3 BJ |
568 | /* |
569 | * Update window information. | |
570 | */ | |
22856bb8 | 571 | if (SEQ_LT(tp->snd_wl1, ti->ti_seq) || tp->snd_wl1 == ti->ti_seq && |
8e65fd66 | 572 | (SEQ_LT(tp->snd_wl2, ti->ti_ack) || |
22856bb8 | 573 | tp->snd_wl2 == ti->ti_ack && ti->ti_win > tp->snd_wnd)) { |
4aed14e3 BJ |
574 | tp->snd_wnd = ti->ti_win; |
575 | tp->snd_wl1 = ti->ti_seq; | |
576 | tp->snd_wl2 = ti->ti_ack; | |
577 | if (tp->snd_wnd > 0) | |
578 | tp->t_timer[TCPT_PERSIST] = 0; | |
579 | } | |
4aed14e3 | 580 | |
2ff61f9d | 581 | /* |
b2db9217 | 582 | * Process segments with URG. |
2ff61f9d | 583 | */ |
9c811062 BJ |
584 | if ((tiflags & TH_URG) && ti->ti_urp && |
585 | TCPS_HAVERCVDFIN(tp->t_state) == 0) { | |
b2db9217 BJ |
586 | /* |
587 | * If this segment advances the known urgent pointer, | |
588 | * then mark the data stream. This should not happen | |
589 | * in CLOSE_WAIT, CLOSING, LAST_ACK or TIME_WAIT STATES since | |
590 | * a FIN has been received from the remote side. | |
591 | * In these states we ignore the URG. | |
592 | */ | |
593 | if (SEQ_GT(ti->ti_seq+ti->ti_urp, tp->rcv_up)) { | |
594 | tp->rcv_up = ti->ti_seq + ti->ti_urp; | |
595 | so->so_oobmark = so->so_rcv.sb_cc + | |
596 | (tp->rcv_up - tp->rcv_nxt) - 1; | |
597 | if (so->so_oobmark == 0) | |
598 | so->so_state |= SS_RCVATMARK; | |
8b5a83bb | 599 | #ifdef TCPTRUEOOB |
b2db9217 | 600 | if ((tp->t_flags & TF_DOOOB) == 0) |
8b5a83bb | 601 | #endif |
b2db9217 BJ |
602 | sohasoutofband(so); |
603 | tp->t_oobflags &= ~TCPOOB_HAVEDATA; | |
604 | } | |
605 | /* | |
606 | * Remove out of band data so doesn't get presented to user. | |
607 | * This can happen independent of advancing the URG pointer, | |
608 | * but if two URG's are pending at once, some out-of-band | |
609 | * data may creep in... ick. | |
610 | */ | |
611 | if (ti->ti_urp <= ti->ti_len) { | |
612 | tcp_pulloutofband(so, ti); | |
8b5a83bb | 613 | } |
5e74df82 | 614 | } |
87e78f19 BJ |
615 | |
616 | /* | |
2ff61f9d BJ |
617 | * Process the segment text, merging it into the TCP sequencing queue, |
618 | * and arranging for acknowledgment of receipt if necessary. | |
619 | * This process logically involves adjusting tp->rcv_wnd as data | |
620 | * is presented to the user (this happens in tcp_usrreq.c, | |
621 | * case PRU_RCVD). If a FIN has already been received on this | |
622 | * connection then we just ignore the text. | |
87e78f19 | 623 | */ |
e832edbc BJ |
624 | if ((ti->ti_len || (tiflags&TH_FIN)) && |
625 | TCPS_HAVERCVDFIN(tp->t_state) == 0) { | |
2ff61f9d | 626 | tiflags = tcp_reass(tp, ti); |
8b5a83bb BJ |
627 | if (tcpnodelack == 0) |
628 | tp->t_flags |= TF_DELACK; | |
629 | else | |
630 | tp->t_flags |= TF_ACKNOW; | |
4aed14e3 | 631 | } else { |
2b4b57cd | 632 | m_freem(m); |
e832edbc | 633 | tiflags &= ~TH_FIN; |
4aed14e3 | 634 | } |
87e78f19 BJ |
635 | |
636 | /* | |
e832edbc BJ |
637 | * If FIN is received ACK the FIN and let the user know |
638 | * that the connection is closing. | |
87e78f19 | 639 | */ |
e832edbc | 640 | if (tiflags & TH_FIN) { |
4aed14e3 BJ |
641 | if (TCPS_HAVERCVDFIN(tp->t_state) == 0) { |
642 | socantrcvmore(so); | |
643 | tp->t_flags |= TF_ACKNOW; | |
644 | tp->rcv_nxt++; | |
645 | } | |
2ff61f9d | 646 | switch (tp->t_state) { |
87e78f19 | 647 | |
2ff61f9d BJ |
648 | /* |
649 | * In SYN_RECEIVED and ESTABLISHED STATES | |
650 | * enter the CLOSE_WAIT state. | |
53a5409e | 651 | */ |
2ff61f9d BJ |
652 | case TCPS_SYN_RECEIVED: |
653 | case TCPS_ESTABLISHED: | |
654 | tp->t_state = TCPS_CLOSE_WAIT; | |
655 | break; | |
53a5409e | 656 | |
2ff61f9d | 657 | /* |
8a13b737 BJ |
658 | * If still in FIN_WAIT_1 STATE FIN has not been acked so |
659 | * enter the CLOSING state. | |
53a5409e | 660 | */ |
2ff61f9d | 661 | case TCPS_FIN_WAIT_1: |
8a13b737 | 662 | tp->t_state = TCPS_CLOSING; |
2ff61f9d | 663 | break; |
87e78f19 | 664 | |
2ff61f9d BJ |
665 | /* |
666 | * In FIN_WAIT_2 state enter the TIME_WAIT state, | |
667 | * starting the time-wait timer, turning off the other | |
668 | * standard timers. | |
669 | */ | |
670 | case TCPS_FIN_WAIT_2: | |
4aed14e3 | 671 | tp->t_state = TCPS_TIME_WAIT; |
a6503abf | 672 | tcp_canceltimers(tp); |
405c9168 | 673 | tp->t_timer[TCPT_2MSL] = 2 * TCPTV_MSL; |
4aed14e3 | 674 | soisdisconnected(so); |
2ff61f9d BJ |
675 | break; |
676 | ||
53a5409e | 677 | /* |
2ff61f9d | 678 | * In TIME_WAIT state restart the 2 MSL time_wait timer. |
53a5409e | 679 | */ |
2ff61f9d | 680 | case TCPS_TIME_WAIT: |
405c9168 | 681 | tp->t_timer[TCPT_2MSL] = 2 * TCPTV_MSL; |
2ff61f9d | 682 | break; |
8a13b737 | 683 | } |
87e78f19 | 684 | } |
4b935108 BJ |
685 | if (so->so_options & SO_DEBUG) |
686 | tcp_trace(TA_INPUT, ostate, tp, &tcp_saveti, 0); | |
8a13b737 BJ |
687 | |
688 | /* | |
689 | * Return any desired output. | |
690 | */ | |
668cc26d | 691 | (void) tcp_output(tp); |
2ff61f9d | 692 | return; |
8a13b737 | 693 | |
2ff61f9d | 694 | dropafterack: |
8a13b737 | 695 | /* |
1e977657 BJ |
696 | * Generate an ACK dropping incoming segment if it occupies |
697 | * sequence space, where the ACK reflects our state. | |
8a13b737 | 698 | */ |
1e977657 BJ |
699 | if ((tiflags&TH_RST) || |
700 | tlen == 0 && (tiflags&(TH_SYN|TH_FIN)) == 0) | |
8a13b737 | 701 | goto drop; |
f3cdd721 BJ |
702 | if (tp->t_inpcb->inp_socket->so_options & SO_DEBUG) |
703 | tcp_trace(TA_RESPOND, ostate, tp, &tcp_saveti, 0); | |
8e65fd66 | 704 | tcp_respond(tp, ti, tp->rcv_nxt, tp->snd_nxt, TH_ACK); |
4b6b94ca | 705 | return; |
8a13b737 BJ |
706 | |
707 | dropwithreset: | |
8b5a83bb | 708 | if (om) |
668cc26d | 709 | (void) m_free(om); |
8a13b737 | 710 | /* |
4aed14e3 | 711 | * Generate a RST, dropping incoming segment. |
8a13b737 BJ |
712 | * Make ACK acceptable to originator of segment. |
713 | */ | |
714 | if (tiflags & TH_RST) | |
715 | goto drop; | |
716 | if (tiflags & TH_ACK) | |
8e65fd66 | 717 | tcp_respond(tp, ti, (tcp_seq)0, ti->ti_ack, TH_RST); |
8a13b737 BJ |
718 | else { |
719 | if (tiflags & TH_SYN) | |
720 | ti->ti_len++; | |
1e977657 BJ |
721 | tcp_respond(tp, ti, ti->ti_seq+ti->ti_len, (tcp_seq)0, |
722 | TH_RST|TH_ACK); | |
8a13b737 | 723 | } |
4b6b94ca | 724 | return; |
8a13b737 | 725 | |
2ff61f9d | 726 | drop: |
8a13b737 BJ |
727 | /* |
728 | * Drop space held by incoming segment and return. | |
729 | */ | |
f3cdd721 BJ |
730 | if (tp && (tp->t_inpcb->inp_socket->so_options & SO_DEBUG)) |
731 | tcp_trace(TA_DROP, ostate, tp, &tcp_saveti, 0); | |
2ff61f9d | 732 | m_freem(m); |
4b935108 | 733 | return; |
2ff61f9d BJ |
734 | } |
735 | ||
8b5a83bb BJ |
736 | tcp_dooptions(tp, om) |
737 | struct tcpcb *tp; | |
738 | struct mbuf *om; | |
5e74df82 | 739 | { |
8b5a83bb BJ |
740 | register u_char *cp; |
741 | int opt, optlen, cnt; | |
742 | ||
743 | cp = mtod(om, u_char *); | |
744 | cnt = om->m_len; | |
745 | for (; cnt > 0; cnt -= optlen, cp += optlen) { | |
746 | opt = cp[0]; | |
747 | if (opt == TCPOPT_EOL) | |
748 | break; | |
749 | if (opt == TCPOPT_NOP) | |
750 | optlen = 1; | |
751 | else | |
752 | optlen = cp[1]; | |
753 | switch (opt) { | |
754 | ||
755 | default: | |
756 | break; | |
757 | ||
758 | case TCPOPT_MAXSEG: | |
759 | if (optlen != 4) | |
760 | continue; | |
761 | tp->t_maxseg = *(u_short *)(cp + 2); | |
93f92b1d | 762 | #if vax || pdp11 |
668cc26d | 763 | tp->t_maxseg = ntohs((u_short)tp->t_maxseg); |
8b5a83bb BJ |
764 | #endif |
765 | break; | |
766 | ||
767 | #ifdef TCPTRUEOOB | |
768 | case TCPOPT_WILLOOB: | |
769 | tp->t_flags |= TF_DOOOB; | |
770 | printf("tp %x dooob\n", tp); | |
771 | break; | |
772 | ||
773 | case TCPOPT_OOBDATA: { | |
774 | int seq; | |
b2db9217 BJ |
775 | register struct socket *so = tp->t_inpcb->inp_socket; |
776 | tcp_seq mark; | |
8b5a83bb | 777 | |
b2db9217 | 778 | if (optlen != 8) |
8b5a83bb BJ |
779 | continue; |
780 | seq = cp[2]; | |
781 | if (seq < tp->t_iobseq) | |
782 | seq += 256; | |
783 | printf("oobdata cp[2] %d iobseq %d seq %d\n", cp[2], tp->t_iobseq, seq); | |
784 | if (seq - tp->t_iobseq > 128) { | |
785 | printf("bad seq\n"); | |
786 | tp->t_oobflags |= TCPOOB_OWEACK; | |
787 | break; | |
788 | } | |
789 | tp->t_iobseq = cp[2]; | |
790 | tp->t_iobc = cp[3]; | |
b2db9217 | 791 | mark = *(tcp_seq *)(cp + 4); |
93f92b1d | 792 | #if vax || pdp11 |
b2db9217 BJ |
793 | mark = ntohl(mark); |
794 | #endif | |
795 | so->so_oobmark = so->so_rcv.sb_cc + (mark-tp->rcv_nxt); | |
796 | if (so->so_oobmark == 0) | |
797 | so->so_state |= SS_RCVATMARK; | |
8b5a83bb | 798 | printf("take oob data %x input iobseq now %x\n", tp->t_iobc, tp->t_iobseq); |
b2db9217 | 799 | sohasoutofband(so); |
8b5a83bb | 800 | break; |
5e74df82 | 801 | } |
8b5a83bb BJ |
802 | |
803 | case TCPOPT_OOBACK: { | |
804 | int seq; | |
805 | ||
806 | if (optlen != 4) | |
807 | continue; | |
808 | if (tp->t_oobseq != cp[2]) { | |
809 | printf("wrong ack\n"); | |
810 | break; | |
811 | } | |
812 | printf("take oob ack %x and cancel rexmt\n", cp[2]); | |
813 | tp->t_oobflags &= ~TCPOOB_NEEDACK; | |
814 | tp->t_timer[TCPT_OOBREXMT] = 0; | |
5e74df82 | 815 | break; |
8b5a83bb BJ |
816 | } |
817 | #endif TCPTRUEOOB | |
818 | } | |
5e74df82 | 819 | } |
668cc26d | 820 | (void) m_free(om); |
5e74df82 BJ |
821 | } |
822 | ||
b2db9217 BJ |
823 | /* |
824 | * Pull out of band byte out of a segment so | |
825 | * it doesn't appear in the user's data queue. | |
826 | * It is still reflected in the segment length for | |
827 | * sequencing purposes. | |
828 | */ | |
829 | tcp_pulloutofband(so, ti) | |
830 | struct socket *so; | |
831 | struct tcpiphdr *ti; | |
832 | { | |
833 | register struct mbuf *m; | |
1acff8ec | 834 | int cnt = ti->ti_urp - 1; |
b2db9217 BJ |
835 | |
836 | m = dtom(ti); | |
837 | while (cnt >= 0) { | |
838 | if (m->m_len > cnt) { | |
839 | char *cp = mtod(m, caddr_t) + cnt; | |
840 | struct tcpcb *tp = sototcpcb(so); | |
841 | ||
842 | tp->t_iobc = *cp; | |
843 | tp->t_oobflags |= TCPOOB_HAVEDATA; | |
668cc26d | 844 | bcopy(cp+1, cp, (unsigned)(m->m_len - cnt - 1)); |
b2db9217 BJ |
845 | m->m_len--; |
846 | return; | |
847 | } | |
848 | cnt -= m->m_len; | |
849 | m = m->m_next; | |
850 | if (m == 0) | |
851 | break; | |
852 | } | |
853 | panic("tcp_pulloutofband"); | |
854 | } | |
855 | ||
2ff61f9d BJ |
856 | /* |
857 | * Insert segment ti into reassembly queue of tcp with | |
858 | * control block tp. Return TH_FIN if reassembly now includes | |
859 | * a segment with FIN. | |
860 | */ | |
f1b2fa5b | 861 | tcp_reass(tp, ti) |
2ff61f9d BJ |
862 | register struct tcpcb *tp; |
863 | register struct tcpiphdr *ti; | |
2ff61f9d BJ |
864 | { |
865 | register struct tcpiphdr *q; | |
8a13b737 | 866 | struct socket *so = tp->t_inpcb->inp_socket; |
e832edbc BJ |
867 | struct mbuf *m; |
868 | int flags; | |
2ff61f9d BJ |
869 | |
870 | /* | |
405c9168 BJ |
871 | * Call with ti==0 after become established to |
872 | * force pre-ESTABLISHED data up to user socket. | |
2ff61f9d | 873 | */ |
405c9168 | 874 | if (ti == 0) |
2ff61f9d | 875 | goto present; |
87e78f19 | 876 | |
2ff61f9d BJ |
877 | /* |
878 | * Find a segment which begins after this one does. | |
879 | */ | |
880 | for (q = tp->seg_next; q != (struct tcpiphdr *)tp; | |
881 | q = (struct tcpiphdr *)q->ti_next) | |
882 | if (SEQ_GT(q->ti_seq, ti->ti_seq)) | |
883 | break; | |
884 | ||
885 | /* | |
886 | * If there is a preceding segment, it may provide some of | |
887 | * our data already. If so, drop the data from the incoming | |
888 | * segment. If it provides all of our data, drop us. | |
889 | */ | |
890 | if ((struct tcpiphdr *)q->ti_prev != (struct tcpiphdr *)tp) { | |
891 | register int i; | |
fd5dc5f0 | 892 | q = (struct tcpiphdr *)q->ti_prev; |
2ff61f9d BJ |
893 | /* conversion to int (in i) handles seq wraparound */ |
894 | i = q->ti_seq + q->ti_len - ti->ti_seq; | |
895 | if (i > 0) { | |
2b4b57cd | 896 | if (i >= ti->ti_len) |
2ff61f9d | 897 | goto drop; |
4ab1a5c3 | 898 | m_adj(dtom(ti), i); |
2b4b57cd | 899 | ti->ti_len -= i; |
2ff61f9d | 900 | ti->ti_seq += i; |
53a5409e | 901 | } |
2ff61f9d BJ |
902 | q = (struct tcpiphdr *)(q->ti_next); |
903 | } | |
87e78f19 | 904 | |
2ff61f9d BJ |
905 | /* |
906 | * While we overlap succeeding segments trim them or, | |
907 | * if they are completely covered, dequeue them. | |
908 | */ | |
fd5dc5f0 | 909 | while (q != (struct tcpiphdr *)tp) { |
2ff61f9d | 910 | register int i = (ti->ti_seq + ti->ti_len) - q->ti_seq; |
fd5dc5f0 BJ |
911 | if (i <= 0) |
912 | break; | |
2ff61f9d | 913 | if (i < q->ti_len) { |
fd5dc5f0 | 914 | q->ti_seq += i; |
2ff61f9d BJ |
915 | q->ti_len -= i; |
916 | m_adj(dtom(q), i); | |
917 | break; | |
ac5e71a1 | 918 | } |
2ff61f9d | 919 | q = (struct tcpiphdr *)q->ti_next; |
473a17a5 | 920 | m = dtom(q->ti_prev); |
2ff61f9d | 921 | remque(q->ti_prev); |
473a17a5 | 922 | m_freem(m); |
2ff61f9d | 923 | } |
87e78f19 | 924 | |
2ff61f9d BJ |
925 | /* |
926 | * Stick new segment in its place. | |
927 | */ | |
928 | insque(ti, q->ti_prev); | |
2ff61f9d | 929 | |
2ff61f9d BJ |
930 | present: |
931 | /* | |
4aed14e3 BJ |
932 | * Present data to user, advancing rcv_nxt through |
933 | * completed sequence space. | |
2ff61f9d | 934 | */ |
e832edbc | 935 | if (TCPS_HAVERCVDSYN(tp->t_state) == 0) |
4aed14e3 | 936 | return (0); |
2b4b57cd | 937 | ti = tp->seg_next; |
e832edbc BJ |
938 | if (ti == (struct tcpiphdr *)tp || ti->ti_seq != tp->rcv_nxt) |
939 | return (0); | |
940 | if (tp->t_state == TCPS_SYN_RECEIVED && ti->ti_len) | |
941 | return (0); | |
942 | do { | |
4aed14e3 BJ |
943 | tp->rcv_nxt += ti->ti_len; |
944 | flags = ti->ti_flags & TH_FIN; | |
2b4b57cd | 945 | remque(ti); |
e832edbc | 946 | m = dtom(ti); |
2b4b57cd | 947 | ti = (struct tcpiphdr *)ti->ti_next; |
e832edbc | 948 | if (so->so_state & SS_CANTRCVMORE) |
668cc26d | 949 | m_freem(m); |
e832edbc BJ |
950 | else |
951 | sbappend(&so->so_rcv, m); | |
952 | } while (ti != (struct tcpiphdr *)tp && ti->ti_seq == tp->rcv_nxt); | |
953 | sorwakeup(so); | |
2ff61f9d BJ |
954 | return (flags); |
955 | drop: | |
956 | m_freem(dtom(ti)); | |
e832edbc | 957 | return (0); |
d52566dd | 958 | } |