Commit | Line | Data |
---|---|---|
8ae0e4b4 | 1 | /* |
0880b18e | 2 | * Copyright (c) 1982, 1986 Regents of the University of California. |
8ae0e4b4 KM |
3 | * All rights reserved. The Berkeley software License Agreement |
4 | * specifies the terms and conditions for redistribution. | |
5 | * | |
10604dba | 6 | * @(#)tcp_subr.c 7.5 (Berkeley) %G% |
8ae0e4b4 | 7 | */ |
ecaa4e6f | 8 | |
20666ad3 JB |
9 | #include "param.h" |
10 | #include "systm.h" | |
11 | #include "mbuf.h" | |
12 | #include "socket.h" | |
13 | #include "socketvar.h" | |
14 | #include "protosw.h" | |
15 | #include "errno.h" | |
f4d55810 | 16 | |
c124e997 | 17 | #include "../net/route.h" |
f4d55810 SL |
18 | #include "../net/if.h" |
19 | ||
20666ad3 JB |
20 | #include "in.h" |
21 | #include "in_pcb.h" | |
22 | #include "in_systm.h" | |
23 | #include "ip.h" | |
24 | #include "ip_var.h" | |
25 | #include "ip_icmp.h" | |
26 | #include "tcp.h" | |
27 | #include "tcp_fsm.h" | |
28 | #include "tcp_seq.h" | |
29 | #include "tcp_timer.h" | |
30 | #include "tcp_var.h" | |
31 | #include "tcpip.h" | |
ecaa4e6f | 32 | |
10604dba MK |
33 | int tcp_ttl = TCP_TTL; |
34 | float tcp_alpha = TCP_ALPHA; | |
35 | float tcp_beta = TCP_BETA; | |
36 | ||
ecaa4e6f BJ |
37 | /* |
38 | * Tcp initialization | |
39 | */ | |
40 | tcp_init() | |
41 | { | |
42 | ||
43 | tcp_iss = 1; /* wrong */ | |
44 | tcb.inp_next = tcb.inp_prev = &tcb; | |
45 | } | |
46 | ||
47 | /* | |
48 | * Create template to be used to send tcp packets on a connection. | |
49 | * Call after host entry created, allocates an mbuf and fills | |
50 | * in a skeletal tcp/ip header, minimizing the amount of work | |
51 | * necessary when the connection is used. | |
52 | */ | |
53 | struct tcpiphdr * | |
54 | tcp_template(tp) | |
55 | struct tcpcb *tp; | |
56 | { | |
57 | register struct inpcb *inp = tp->t_inpcb; | |
58 | register struct mbuf *m; | |
59 | register struct tcpiphdr *n; | |
60 | ||
ece01391 MK |
61 | if ((n = tp->t_template) == 0) { |
62 | m = m_get(M_WAIT, MT_HEADER); | |
63 | if (m == NULL) | |
64 | return (0); | |
65 | m->m_off = MMAXOFF - sizeof (struct tcpiphdr); | |
66 | m->m_len = sizeof (struct tcpiphdr); | |
67 | n = mtod(m, struct tcpiphdr *); | |
68 | } | |
ecaa4e6f BJ |
69 | n->ti_next = n->ti_prev = 0; |
70 | n->ti_x1 = 0; | |
71 | n->ti_pr = IPPROTO_TCP; | |
72 | n->ti_len = htons(sizeof (struct tcpiphdr) - sizeof (struct ip)); | |
73 | n->ti_src = inp->inp_laddr; | |
74 | n->ti_dst = inp->inp_faddr; | |
75 | n->ti_sport = inp->inp_lport; | |
76 | n->ti_dport = inp->inp_fport; | |
77 | n->ti_seq = 0; | |
0974b45c | 78 | n->ti_ack = 0; |
ecaa4e6f BJ |
79 | n->ti_x2 = 0; |
80 | n->ti_off = 5; | |
81 | n->ti_flags = 0; | |
82 | n->ti_win = 0; | |
83 | n->ti_sum = 0; | |
84 | n->ti_urp = 0; | |
85 | return (n); | |
86 | } | |
87 | ||
88 | /* | |
405c9168 BJ |
89 | * Send a single message to the TCP at address specified by |
90 | * the given TCP/IP header. If flags==0, then we make a copy | |
91 | * of the tcpiphdr at ti and send directly to the addressed host. | |
92 | * This is used to force keep alive messages out using the TCP | |
93 | * template for a connection tp->t_template. If flags are given | |
94 | * then we send a message back to the TCP which originated the | |
95 | * segment ti, and discard the mbuf containing it and any other | |
96 | * attached mbufs. | |
97 | * | |
98 | * In any case the ack and sequence number of the transmitted | |
99 | * segment are as specified by the parameters. | |
ecaa4e6f | 100 | */ |
8e65fd66 BJ |
101 | tcp_respond(tp, ti, ack, seq, flags) |
102 | struct tcpcb *tp; | |
ecaa4e6f | 103 | register struct tcpiphdr *ti; |
0974b45c | 104 | tcp_seq ack, seq; |
ecaa4e6f BJ |
105 | int flags; |
106 | { | |
8b6ad229 | 107 | register struct mbuf *m; |
1e977657 | 108 | int win = 0, tlen; |
c124e997 | 109 | struct route *ro = 0; |
8b6ad229 | 110 | extern int tcp_keeplen; |
ecaa4e6f | 111 | |
c124e997 | 112 | if (tp) { |
8e65fd66 | 113 | win = sbspace(&tp->t_inpcb->inp_socket->so_rcv); |
c124e997 SL |
114 | ro = &tp->t_inpcb->inp_route; |
115 | } | |
405c9168 | 116 | if (flags == 0) { |
cce93e4b | 117 | m = m_get(M_DONTWAIT, MT_HEADER); |
5cdc4d65 | 118 | if (m == NULL) |
405c9168 | 119 | return; |
8b6ad229 MK |
120 | tlen = tcp_keeplen; |
121 | m->m_len = sizeof (struct tcpiphdr) + tlen; | |
405c9168 BJ |
122 | *mtod(m, struct tcpiphdr *) = *ti; |
123 | ti = mtod(m, struct tcpiphdr *); | |
124 | flags = TH_ACK; | |
125 | } else { | |
4aed14e3 | 126 | m = dtom(ti); |
405c9168 BJ |
127 | m_freem(m->m_next); |
128 | m->m_next = 0; | |
1acff8ec | 129 | m->m_off = (int)ti - (int)m; |
8b6ad229 | 130 | tlen = 0; |
405c9168 | 131 | m->m_len = sizeof (struct tcpiphdr); |
0974b45c | 132 | #define xchg(a,b,type) { type t; t=a; a=b; b=t; } |
405c9168 BJ |
133 | xchg(ti->ti_dst.s_addr, ti->ti_src.s_addr, u_long); |
134 | xchg(ti->ti_dport, ti->ti_sport, u_short); | |
ecaa4e6f | 135 | #undef xchg |
405c9168 | 136 | } |
0974b45c BJ |
137 | ti->ti_next = ti->ti_prev = 0; |
138 | ti->ti_x1 = 0; | |
af8f6a21 | 139 | ti->ti_len = htons((u_short)(sizeof (struct tcphdr) + tlen)); |
2c48b3f8 BJ |
140 | ti->ti_seq = htonl(seq); |
141 | ti->ti_ack = htonl(ack); | |
0974b45c BJ |
142 | ti->ti_x2 = 0; |
143 | ti->ti_off = sizeof (struct tcphdr) >> 2; | |
ecaa4e6f | 144 | ti->ti_flags = flags; |
af8f6a21 | 145 | ti->ti_win = htons((u_short)win); |
8e65fd66 | 146 | ti->ti_urp = 0; |
f3cdd721 | 147 | ti->ti_sum = in_cksum(m, sizeof (struct tcpiphdr) + tlen); |
1e977657 | 148 | ((struct ip *)ti)->ip_len = sizeof (struct tcpiphdr) + tlen; |
10604dba | 149 | ((struct ip *)ti)->ip_ttl = tcp_ttl; |
c124e997 | 150 | (void) ip_output(m, (struct mbuf *)0, ro, 0); |
ecaa4e6f | 151 | } |
a6503abf | 152 | |
0974b45c BJ |
153 | /* |
154 | * Create a new TCP control block, making an | |
155 | * empty reassembly queue and hooking it to the argument | |
156 | * protocol control block. | |
157 | */ | |
a6503abf BJ |
158 | struct tcpcb * |
159 | tcp_newtcpcb(inp) | |
160 | struct inpcb *inp; | |
161 | { | |
cce93e4b | 162 | struct mbuf *m = m_getclr(M_DONTWAIT, MT_PCB); |
a6503abf | 163 | register struct tcpcb *tp; |
a6503abf | 164 | |
5cdc4d65 SL |
165 | if (m == NULL) |
166 | return ((struct tcpcb *)0); | |
a6503abf | 167 | tp = mtod(m, struct tcpcb *); |
a6503abf | 168 | tp->seg_next = tp->seg_prev = (struct tcpiphdr *)tp; |
247c6a81 | 169 | tp->t_maxseg = TCP_MSS; |
3e60e1e6 | 170 | tp->t_flags = 0; /* sends options! */ |
a6503abf | 171 | tp->t_inpcb = inp; |
247c6a81 | 172 | tp->t_srtt = TCPTV_SRTTBASE; |
05586739 | 173 | tp->snd_cwnd = sbspace(&inp->inp_socket->so_snd); |
a6503abf BJ |
174 | inp->inp_ppcb = (caddr_t)tp; |
175 | return (tp); | |
176 | } | |
177 | ||
0974b45c BJ |
178 | /* |
179 | * Drop a TCP connection, reporting | |
180 | * the specified error. If connection is synchronized, | |
181 | * then send a RST to peer. | |
182 | */ | |
0e3936fa | 183 | struct tcpcb * |
a6503abf | 184 | tcp_drop(tp, errno) |
0e3936fa | 185 | register struct tcpcb *tp; |
a6503abf BJ |
186 | int errno; |
187 | { | |
188 | struct socket *so = tp->t_inpcb->inp_socket; | |
189 | ||
d3504cc0 | 190 | if (TCPS_HAVERCVDSYN(tp->t_state)) { |
a6503abf | 191 | tp->t_state = TCPS_CLOSED; |
39d536e6 | 192 | (void) tcp_output(tp); |
35f3fc10 MK |
193 | tcpstat.tcps_drops++; |
194 | } else | |
195 | tcpstat.tcps_conndrops++; | |
a6503abf | 196 | so->so_error = errno; |
0e3936fa | 197 | return (tcp_close(tp)); |
a6503abf BJ |
198 | } |
199 | ||
0974b45c BJ |
200 | /* |
201 | * Close a TCP control block: | |
202 | * discard all space held by the tcp | |
203 | * discard internet protocol block | |
204 | * wake up any sleepers | |
205 | */ | |
0e3936fa | 206 | struct tcpcb * |
a6503abf BJ |
207 | tcp_close(tp) |
208 | register struct tcpcb *tp; | |
209 | { | |
210 | register struct tcpiphdr *t; | |
364801f5 BJ |
211 | struct inpcb *inp = tp->t_inpcb; |
212 | struct socket *so = inp->inp_socket; | |
13e2480b | 213 | register struct mbuf *m; |
a6503abf | 214 | |
a6503abf | 215 | t = tp->seg_next; |
13e2480b SL |
216 | while (t != (struct tcpiphdr *)tp) { |
217 | t = (struct tcpiphdr *)t->ti_next; | |
218 | m = dtom(t->ti_prev); | |
219 | remque(t->ti_prev); | |
220 | m_freem(m); | |
221 | } | |
0974b45c | 222 | if (tp->t_template) |
a6503abf | 223 | (void) m_free(dtom(tp->t_template)); |
0974b45c BJ |
224 | if (tp->t_tcpopt) |
225 | (void) m_free(dtom(tp->t_tcpopt)); | |
a6503abf | 226 | (void) m_free(dtom(tp)); |
364801f5 | 227 | inp->inp_ppcb = 0; |
4aed14e3 | 228 | soisdisconnected(so); |
86676257 | 229 | in_pcbdetach(inp); |
35f3fc10 | 230 | tcpstat.tcps_closed++; |
0e3936fa | 231 | return ((struct tcpcb *)0); |
a6503abf BJ |
232 | } |
233 | ||
a6503abf BJ |
234 | tcp_drain() |
235 | { | |
a6503abf | 236 | |
a6503abf BJ |
237 | } |
238 | ||
be841dc3 MK |
239 | /* |
240 | * Notify a tcp user of an asynchronous error; | |
241 | * just wake up so that he can collect error status. | |
242 | */ | |
243 | tcp_notify(inp) | |
244 | register struct inpcb *inp; | |
245 | { | |
246 | ||
247 | wakeup((caddr_t) &inp->inp_socket->so_timeo); | |
248 | sorwakeup(inp->inp_socket); | |
249 | sowwakeup(inp->inp_socket); | |
250 | } | |
7c626d4d | 251 | tcp_ctlinput(cmd, sa) |
72e4f44e | 252 | int cmd; |
7c626d4d | 253 | struct sockaddr *sa; |
a6503abf | 254 | { |
39674d5f | 255 | extern u_char inetctlerrmap[]; |
7c626d4d | 256 | struct sockaddr_in *sin; |
62a291b2 | 257 | int tcp_quench(), in_rtchange(); |
39674d5f | 258 | |
7c626d4d MK |
259 | if ((unsigned)cmd > PRC_NCMDS) |
260 | return; | |
261 | if (sa->sa_family != AF_INET && sa->sa_family != AF_IMPLINK) | |
262 | return; | |
263 | sin = (struct sockaddr_in *)sa; | |
264 | if (sin->sin_addr.s_addr == INADDR_ANY) | |
39674d5f | 265 | return; |
39674d5f | 266 | |
7c626d4d | 267 | switch (cmd) { |
39674d5f SL |
268 | |
269 | case PRC_QUENCH: | |
7c626d4d | 270 | in_pcbnotify(&tcb, &sin->sin_addr, 0, tcp_quench); |
62a291b2 MK |
271 | break; |
272 | ||
7c626d4d | 273 | case PRC_ROUTEDEAD: |
62a291b2 MK |
274 | case PRC_REDIRECT_NET: |
275 | case PRC_REDIRECT_HOST: | |
7c626d4d MK |
276 | case PRC_REDIRECT_TOSNET: |
277 | case PRC_REDIRECT_TOSHOST: | |
278 | in_pcbnotify(&tcb, &sin->sin_addr, 0, in_rtchange); | |
39674d5f SL |
279 | break; |
280 | ||
39674d5f | 281 | default: |
62a291b2 MK |
282 | if (inetctlerrmap[cmd] == 0) |
283 | return; /* XXX */ | |
7c626d4d | 284 | in_pcbnotify(&tcb, &sin->sin_addr, (int)inetctlerrmap[cmd], |
be841dc3 | 285 | tcp_notify); |
39674d5f | 286 | } |
a6503abf | 287 | } |
05586739 MK |
288 | |
289 | /* | |
290 | * When a source quench is received, close congestion window | |
291 | * to 80% of the outstanding data (but not less than one segment). | |
292 | */ | |
293 | tcp_quench(inp) | |
294 | struct inpcb *inp; | |
295 | { | |
296 | struct tcpcb *tp = intotcpcb(inp); | |
297 | ||
7c626d4d MK |
298 | if (tp) |
299 | tp->snd_cwnd = MAX(8 * (tp->snd_nxt - tp->snd_una) / 10, | |
300 | tp->t_maxseg); | |
05586739 | 301 | } |