Commit | Line | Data |
---|---|---|
905758fb | 1 | /* ip_input.c 1.8 81/10/28 */ |
6e8b2eca | 2 | |
e1d82856 | 3 | #include "../h/param.h" |
d10bd5b7 | 4 | #include "../h/systm.h" |
e6dd2097 BJ |
5 | #include "../h/clock.h" |
6 | #include "../h/mbuf.h" | |
7 | #include "../inet/inet.h" | |
8 | #include "../inet/inet_systm.h" | |
9 | #include "../inet/imp.h" | |
10 | #include "../inet/ip.h" /* belongs before inet.h */ | |
11 | #include "../inet/ip_icmp.h" | |
12 | #include "../inet/tcp.h" | |
13 | ||
14 | int nosum = 0; | |
15 | ||
16 | struct ip *ip_reass(); | |
17 | ||
18 | /* | |
19 | * Ip input routines. | |
20 | */ | |
21 | ||
22 | /* | |
23 | * Ip input routine. Checksum and byte swap header. If fragmented | |
24 | * try to reassamble. If complete and fragment queue exists, discard. | |
25 | * Process options. Pass to next level. | |
26 | */ | |
27 | ip_input(m0) | |
28 | struct mbuf *m0; | |
e1d82856 | 29 | { |
e6dd2097 | 30 | register int i; |
e1d82856 BJ |
31 | register struct ip *ip, *q; |
32 | register struct ipq *fp; | |
e6dd2097 | 33 | register struct mbuf *m = m0; |
e1d82856 | 34 | int hlen; |
e1d82856 BJ |
35 | |
36 | COUNT(IP_INPUT); | |
e6dd2097 BJ |
37 | /* |
38 | * Check header and byteswap. | |
39 | */ | |
40 | ip = mtod(m, struct ip *); | |
41 | if ((hlen = ip->ip_hl << 2) > m->m_len) { | |
42 | printf("ip hdr ovflo\n"); | |
43 | m_freem(m); | |
e1d82856 BJ |
44 | return; |
45 | } | |
e6dd2097 | 46 | i = ip->ip_sum; |
e1d82856 | 47 | ip->ip_sum = 0; |
e6dd2097 BJ |
48 | #ifdef vax |
49 | if (hlen == sizeof (struct ip)) { | |
50 | asm("movl r10,r0; movl (r0)+,r1; addl2 (r0)+,r1"); | |
51 | asm("adwc (r0)+,r1; adwc (r0)+,r1; adwc (r0)+,r1"); | |
52 | asm("adwc $0,r1; ashl $-16,r1,r0; addw2 r0,r1"); | |
53 | asm("adwc $0,r1"); /* ### */ | |
54 | asm("mcoml r1,r1; movzwl r1,r1; subl2 r1,r11"); | |
55 | } else | |
56 | #endif | |
57 | i -= cksum(m, hlen); | |
58 | if (i) { | |
e1d82856 BJ |
59 | netstat.ip_badsum++; |
60 | if (!nosum) { | |
e6dd2097 BJ |
61 | m_freem(m); |
62 | return; | |
e1d82856 BJ |
63 | } |
64 | } | |
e6dd2097 BJ |
65 | ip->ip_len = ntohs(ip->ip_len); |
66 | ip->ip_id = ntohs(ip->ip_id); | |
67 | ip->ip_off = ntohs(ip->ip_off); | |
e1d82856 | 68 | |
d10bd5b7 | 69 | /* |
e6dd2097 BJ |
70 | * Check that the amount of data in the buffers |
71 | * is as at least much as the IP header would have us expect. | |
72 | * Trim mbufs if longer than we expect. | |
73 | * Drop packet if shorter than we expect. | |
d10bd5b7 | 74 | */ |
e6dd2097 BJ |
75 | i = 0; |
76 | for (; m != NULL; m = m->m_next) | |
e1d82856 | 77 | i += m->m_len; |
e6dd2097 BJ |
78 | m = m0; |
79 | if (i != ip->ip_len) { | |
80 | if (i < ip->ip_len) { | |
81 | printf("ip_input: short packet\n"); | |
82 | m_freem(m); | |
83 | return; | |
d10bd5b7 | 84 | } |
e6dd2097 | 85 | m_adj(m, ip->ip_len - i); |
d10bd5b7 | 86 | } |
e1d82856 | 87 | |
e6dd2097 BJ |
88 | /* |
89 | * Process options and, if not destined for us, | |
90 | * ship it on. | |
91 | */ | |
92 | if (hlen > sizeof (struct ip)) | |
93 | ip_dooptions(ip, hlen); | |
94 | if (ip->ip_dst.s_addr != n_lhost.s_addr) { | |
95 | if (--ip->ip_ttl == 0) { | |
96 | icmp_error(ip, ICMP_TIMXCEED); | |
97 | return; | |
98 | } | |
99 | ip_output(dtom(ip)); | |
100 | return; | |
d10bd5b7 | 101 | } |
e1d82856 | 102 | |
e6dd2097 BJ |
103 | /* |
104 | * Look for queue of fragments | |
105 | * of this datagram. | |
106 | */ | |
107 | for (fp = ipq.next; fp != &ipq; fp = fp->next) | |
108 | if (ip->ip_id == fp->ipq_id && | |
109 | ip->ip_src.s_addr == fp->ipq_src.s_addr && | |
110 | ip->ip_dst.s_addr == fp->ipq_dst.s_addr && | |
111 | ip->ip_p == fp->ipq_p) | |
112 | goto found; | |
113 | fp = 0; | |
114 | found: | |
e1d82856 | 115 | |
e6dd2097 BJ |
116 | /* |
117 | * Adjust ip_len to not reflect header, | |
118 | * set ip_mff if more fragments are expected, | |
119 | * convert offset of this to bytes. | |
120 | */ | |
121 | ip->ip_len -= hlen; | |
122 | ip->ip_mff = 0; | |
123 | if (ip->ip_off & IP_MF) | |
124 | ip->ip_mff = 1; | |
125 | ip->ip_off <<= 3; | |
e1d82856 | 126 | |
e6dd2097 BJ |
127 | /* |
128 | * If datagram marked as having more fragments | |
129 | * or if this is not the first fragment, | |
130 | * attempt reassembly; if it succeeds, proceed. | |
131 | */ | |
132 | if (ip->ip_mff || ip->ip_off) { | |
133 | ip = ip_reass(ip, fp); | |
134 | if (ip == 0) | |
d10bd5b7 | 135 | return; |
e6dd2097 BJ |
136 | hlen = ip->ip_hl << 2; |
137 | m = dtom(ip); | |
138 | } else | |
139 | if (fp) | |
140 | (void) ip_freef(fp); | |
e1d82856 | 141 | |
e6dd2097 BJ |
142 | /* |
143 | * Switch out to protocol specific routine. | |
144 | * SHOULD GO THROUGH PROTOCOL SWITCH TABLE | |
145 | */ | |
146 | switch (ip->ip_p) { | |
e1d82856 | 147 | |
e6dd2097 BJ |
148 | case IPPROTO_ICMP: |
149 | icmp_input(m); | |
150 | break; | |
d10bd5b7 | 151 | |
e6dd2097 BJ |
152 | case IPPROTO_TCP: |
153 | if (hlen > sizeof (struct ip)) | |
154 | ip_stripoptions(ip, hlen); | |
155 | tcp_input(m); | |
156 | break; | |
e1d82856 | 157 | |
e6dd2097 BJ |
158 | case IPPROTO_UDP: |
159 | if (hlen > sizeof (struct ip)) | |
160 | ip_stripoptions(ip, hlen); | |
161 | udp_input(m); | |
162 | break; | |
e1d82856 | 163 | |
e6dd2097 BJ |
164 | default: |
165 | raw_input(m); | |
166 | break; | |
167 | } | |
168 | } | |
e1d82856 | 169 | |
e6dd2097 BJ |
170 | /* |
171 | * Take incoming datagram fragment and try to | |
172 | * reassamble it into whole datagram. If a chain for | |
173 | * reassembly of this datagram already exists, then it | |
174 | * is given as fp; otherwise have to make a chain. | |
175 | */ | |
176 | struct ip * | |
177 | ip_reass(ip, fp) | |
178 | register struct ip *ip; | |
179 | register struct ipq *fp; | |
180 | { | |
181 | register struct mbuf *m = dtom(ip); | |
182 | register struct ip *q; | |
183 | struct mbuf *t; | |
184 | int hlen = ip->ip_hl << 2; | |
185 | int i, next; | |
d10bd5b7 | 186 | |
e6dd2097 BJ |
187 | /* |
188 | * Presence of header sizes in mbufs | |
189 | * would confuse code below. | |
190 | */ | |
191 | m->m_off += hlen; | |
192 | m->m_len -= hlen; | |
d10bd5b7 | 193 | |
e6dd2097 BJ |
194 | /* |
195 | * If first fragment to arrive, create a reassembly queue. | |
196 | */ | |
197 | if (fp == 0) { | |
198 | if ((t = m_get(1)) == NULL) | |
199 | goto dropfrag; | |
200 | t->m_off = MMINOFF; | |
201 | fp = mtod(t, struct ipq *); | |
202 | insque(fp, &ipq); | |
203 | fp->ipq_ttl = IPFRAGTTL; | |
204 | fp->ipq_p = ip->ip_p; | |
205 | fp->ipq_id = ip->ip_id; | |
206 | fp->ipq_next = fp->ipq_prev = (struct ip *)fp; | |
207 | fp->ipq_src = ip->ip_src; | |
208 | fp->ipq_dst = ip->ip_dst; | |
209 | } | |
e1d82856 | 210 | |
e6dd2097 BJ |
211 | /* |
212 | * Find a segment which begins after this one does. | |
213 | */ | |
214 | for (q = fp->ipq_next; q != (struct ip *)fp; q = q->ip_next) | |
215 | if (q->ip_off > ip->ip_off) | |
216 | break; | |
e1d82856 | 217 | |
e6dd2097 BJ |
218 | /* |
219 | * If there is a preceding segment, it may provide some of | |
220 | * our data already. If so, drop the data from the incoming | |
221 | * segment. If it provides all of our data, drop us. | |
222 | */ | |
223 | if (q->ip_prev != (struct ip *)fp) { | |
224 | i = q->ip_prev->ip_off + q->ip_prev->ip_len - ip->ip_off; | |
225 | if (i > 0) { | |
226 | if (i >= ip->ip_len) | |
227 | goto dropfrag; | |
228 | m_adj(dtom(ip), i); | |
229 | ip->ip_off += i; | |
230 | ip->ip_len -= i; | |
e1d82856 | 231 | } |
d10bd5b7 | 232 | } |
e1d82856 | 233 | |
e6dd2097 BJ |
234 | /* |
235 | * While we overlap succeeding segments trim them or, | |
236 | * if they are completely covered, dequeue them. | |
237 | */ | |
238 | while (q != (struct ip *)fp && ip->ip_off + ip->ip_len > q->ip_off) { | |
239 | i = (ip->ip_off + ip->ip_len) - q->ip_off; | |
240 | if (i < q->ip_len) { | |
241 | q->ip_len -= i; | |
242 | m_adj(dtom(q), i); | |
243 | break; | |
244 | } | |
245 | q = q->ip_next; | |
246 | m_freem(dtom(q->ip_prev)); | |
247 | ip_deq(q->ip_prev); | |
248 | } | |
e1d82856 | 249 | |
e6dd2097 BJ |
250 | /* |
251 | * Stick new segment in its place; | |
252 | * check for complete reassembly. | |
253 | */ | |
254 | ip_enq(ip, q->ip_prev); | |
255 | next = 0; | |
256 | for (q = fp->ipq_next; q != (struct ip *)fp; q = q->ip_next) { | |
257 | if (q->ip_off != next) | |
258 | return (0); | |
259 | next += q->ip_len; | |
260 | } | |
261 | if (q->ip_prev->ip_mff) | |
262 | return (0); | |
e1d82856 | 263 | |
e6dd2097 BJ |
264 | /* |
265 | * Reassembly is complete; concatenate fragments. | |
266 | */ | |
267 | q = fp->ipq_next; | |
268 | m = dtom(q); | |
269 | t = m->m_next; | |
270 | m->m_next = 0; | |
271 | m_cat(m, t); | |
272 | while ((q = q->ip_next) != (struct ip *)fp) | |
273 | m_cat(m, dtom(q)); | |
e1d82856 | 274 | |
e6dd2097 BJ |
275 | /* |
276 | * Create header for new ip packet by | |
277 | * modifying header of first packet; | |
278 | * dequeue and discard fragment reassembly header. | |
279 | * Make header visible. | |
280 | */ | |
281 | ip = fp->ipq_next; | |
282 | ip->ip_len = next; | |
283 | ip->ip_src = fp->ipq_src; | |
284 | ip->ip_dst = fp->ipq_dst; | |
285 | remque(fp); | |
286 | m_free(dtom(fp)); | |
287 | m = dtom(ip); | |
288 | m->m_len += sizeof (struct ip); | |
289 | m->m_off -= sizeof (struct ip); | |
290 | return (ip); | |
291 | ||
292 | dropfrag: | |
293 | m_freem(m); | |
294 | return (0); | |
e1d82856 BJ |
295 | } |
296 | ||
e6dd2097 BJ |
297 | /* |
298 | * Free a fragment reassembly header and all | |
299 | * associated datagrams. | |
300 | */ | |
301 | struct ipq * | |
302 | ip_freef(fp) | |
303 | struct ipq *fp; | |
e1d82856 BJ |
304 | { |
305 | register struct ip *q; | |
e6dd2097 BJ |
306 | struct mbuf *m; |
307 | ||
308 | for (q = fp->ipq_next; q != (struct ip *)fp; q = q->ip_next) | |
309 | m_freem(dtom(q)); | |
310 | m = dtom(fp); | |
311 | fp = fp->next; | |
312 | remque(fp->prev); | |
313 | m_free(m); | |
314 | return (fp); | |
e1d82856 BJ |
315 | } |
316 | ||
e6dd2097 BJ |
317 | /* |
318 | * Put an ip fragment on a reassembly chain. | |
319 | * Like insque, but pointers in middle of structure. | |
320 | */ | |
321 | ip_enq(p, prev) | |
322 | register struct ip *p; | |
323 | register struct ip *prev; | |
e1d82856 | 324 | { |
e6dd2097 | 325 | COUNT(IP_ENQ); |
e1d82856 | 326 | |
e6dd2097 BJ |
327 | p->ip_prev = prev; |
328 | p->ip_next = prev->ip_next; | |
329 | prev->ip_next->ip_prev = p; | |
330 | prev->ip_next = p; | |
e1d82856 BJ |
331 | } |
332 | ||
e6dd2097 BJ |
333 | /* |
334 | * To ip_enq as remque is to insque. | |
335 | */ | |
336 | ip_deq(p) | |
337 | register struct ip *p; | |
e1d82856 | 338 | { |
e6dd2097 BJ |
339 | COUNT(IP_DEQ); |
340 | ||
341 | p->ip_prev->ip_next = p->ip_next; | |
342 | p->ip_next->ip_prev = p->ip_prev; | |
e1d82856 BJ |
343 | } |
344 | ||
e6dd2097 BJ |
345 | /* |
346 | * IP timer processing; | |
347 | * if a timer expires on a reassembly | |
348 | * queue, discard it. | |
349 | */ | |
350 | ip_timeo() | |
e1d82856 | 351 | { |
e6dd2097 | 352 | register struct ip *q; |
e1d82856 | 353 | register struct ipq *fp; |
e6dd2097 BJ |
354 | int s = splnet(); |
355 | COUNT(IP_TIMEO); | |
e1d82856 | 356 | |
905758fb | 357 | for (fp = ipq.next; fp != &ipq; ) |
e6dd2097 BJ |
358 | if (--fp->ipq_ttl == 0) |
359 | fp = ip_freef(fp); | |
360 | else | |
361 | fp = fp->next; | |
362 | timeout(ip_timeo, 0, hz); | |
363 | splx(s); | |
e1d82856 BJ |
364 | } |
365 | ||
e6dd2097 BJ |
366 | /* |
367 | * Do option processing on a datagram, | |
368 | * possibly discarding it if bad options | |
369 | * are encountered. | |
370 | */ | |
371 | ip_dooptions(ip) | |
372 | struct ip *ip; | |
e1d82856 | 373 | { |
e6dd2097 BJ |
374 | register u_char *cp; |
375 | int opt, optlen, cnt, s; | |
376 | struct inet_addr *sp; | |
377 | ||
378 | cp = (u_char *)(ip + 1); | |
379 | cnt = (ip->ip_hl << 2) - sizeof (struct ip); | |
380 | for (; cnt > 0; cnt -= optlen, cp += optlen) { | |
381 | opt = cp[0]; | |
382 | if (opt == IPOPT_EOL) | |
383 | break; | |
384 | if (opt == IPOPT_NOP) | |
385 | optlen = 1; | |
386 | else | |
387 | optlen = cp[1]; | |
388 | switch (opt) { | |
e1d82856 | 389 | |
e6dd2097 BJ |
390 | default: |
391 | break; | |
e1d82856 | 392 | |
e6dd2097 BJ |
393 | case IPOPT_LSRR: |
394 | case IPOPT_SSRR: | |
395 | if (cp[2] < 4 || cp[2] > optlen - 3) | |
396 | break; | |
397 | sp = (struct inet_addr *)(cp+cp[2]); | |
398 | if (n_lhost.s_addr == *(u_long *)sp) { | |
399 | if (opt == IPOPT_SSRR) { | |
400 | /* make sure *sp directly accessible*/ | |
401 | } | |
402 | ip->ip_dst = *sp; | |
403 | *sp = n_lhost; | |
404 | cp[2] += 4; | |
405 | } | |
406 | break; | |
407 | ||
408 | case IPOPT_TS: | |
409 | if (cp[2] < 5) | |
410 | goto bad; | |
411 | if (cp[2] > cp[1] - 3) { | |
412 | if ((cp[3] & 0xf0) == 0xf0) | |
413 | goto bad; | |
414 | cp[3] += 0x10; | |
415 | break; | |
416 | } | |
417 | sp = (struct inet_addr *)(cp+cp[2]); | |
418 | switch (cp[3] & 0xf) { | |
e1d82856 | 419 | |
e6dd2097 BJ |
420 | case IPOPT_TS_TSONLY: |
421 | break; | |
e1d82856 | 422 | |
e6dd2097 BJ |
423 | case IPOPT_TS_TSANDADDR: |
424 | if (cp[2] > cp[1] - 7) | |
425 | goto bad; | |
426 | break; | |
427 | ||
428 | case IPOPT_TS_PRESPEC: | |
429 | if (*(u_long *)sp != n_lhost.s_addr) | |
430 | break; | |
431 | if (cp[2] > cp[1] - 7) | |
432 | goto bad; | |
433 | cp[1] += 4; | |
e1d82856 BJ |
434 | break; |
435 | ||
436 | default: | |
e6dd2097 | 437 | goto bad; |
e1d82856 | 438 | } |
e6dd2097 BJ |
439 | s = spl6(); |
440 | *(int *)sp = (time % SECDAY) * 1000 + (lbolt*1000/hz); | |
441 | splx(s); | |
442 | cp[1] += 4; | |
443 | } | |
e1d82856 | 444 | } |
e6dd2097 BJ |
445 | return (0); |
446 | bad: | |
447 | /* SHOULD FORCE ICMP MESSAGE */ | |
448 | return (-1); | |
e1d82856 BJ |
449 | } |
450 | ||
e6dd2097 BJ |
451 | /* |
452 | * Strip out IP options, e.g. before passing | |
453 | * to higher level protocol in the kernel. | |
454 | */ | |
455 | ip_stripoptions(ip) | |
456 | struct ip *ip; | |
e1d82856 | 457 | { |
e6dd2097 BJ |
458 | register int i; |
459 | register struct mbuf *m; | |
460 | char *op; | |
461 | int olen; | |
462 | COUNT(IP_OPT); | |
463 | ||
464 | olen = (ip->ip_hl<<2) - sizeof (struct ip); | |
465 | op = (caddr_t)ip + olen; | |
466 | m = dtom(++ip); | |
467 | i = m->m_len - (sizeof (struct ip) + olen); | |
468 | bcopy((caddr_t)ip+olen, (caddr_t)ip, i); | |
469 | m->m_len -= i; | |
e1d82856 | 470 | } |
d10bd5b7 | 471 | |
e6dd2097 BJ |
472 | /* stubs */ |
473 | ||
474 | icmp_error(ip, error) | |
e1d82856 | 475 | { |
e6dd2097 BJ |
476 | |
477 | m_freem(dtom(ip)); | |
e1d82856 BJ |
478 | } |
479 | ||
e6dd2097 BJ |
480 | icmp_input(m) |
481 | struct mbuf *m; | |
e1d82856 | 482 | { |
e1d82856 | 483 | |
e6dd2097 BJ |
484 | printf("icmp_input %x\n", m); |
485 | } | |
e1d82856 | 486 | |
e6dd2097 BJ |
487 | udp_input(m) |
488 | struct mbuf *m; | |
489 | { | |
e1d82856 | 490 | |
e6dd2097 BJ |
491 | printf("udp_input %x\n", m); |
492 | } | |
e1d82856 | 493 | |
e6dd2097 BJ |
494 | raw_input(m) |
495 | struct mbuf *m; | |
496 | { | |
e1d82856 | 497 | |
e6dd2097 | 498 | printf("raw_input %x\n", m); |
e1d82856 | 499 | } |