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1.1 cgd 1: /*
2: * Copyright (c) 1982, 1986, 1988 Regents of the University of California.
3: * All rights reserved.
4: *
5: * Redistribution and use in source and binary forms, with or without
6: * modification, are permitted provided that the following conditions
7: * are met:
8: * 1. Redistributions of source code must retain the above copyright
9: * notice, this list of conditions and the following disclaimer.
10: * 2. Redistributions in binary form must reproduce the above copyright
11: * notice, this list of conditions and the following disclaimer in the
12: * documentation and/or other materials provided with the distribution.
13: * 3. All advertising materials mentioning features or use of this software
14: * must display the following acknowledgement:
15: * This product includes software developed by the University of
16: * California, Berkeley and its contributors.
17: * 4. Neither the name of the University nor the names of its contributors
18: * may be used to endorse or promote products derived from this software
19: * without specific prior written permission.
20: *
21: * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22: * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23: * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24: * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25: * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26: * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27: * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28: * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29: * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30: * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31: * SUCH DAMAGE.
32: *
1.3 cgd 33: * from: @(#)ip_input.c 7.19 (Berkeley) 5/25/91
1.10 ! brezak 34: * $Id: ip_input.c,v 1.9 1994/01/10 20:14:19 mycroft Exp $
1.1 cgd 35: */
36:
1.5 mycroft 37: #include <sys/param.h>
38: #include <sys/systm.h>
39: #include <sys/malloc.h>
40: #include <sys/mbuf.h>
41: #include <sys/domain.h>
42: #include <sys/protosw.h>
43: #include <sys/socket.h>
44: #include <sys/errno.h>
45: #include <sys/time.h>
46: #include <sys/kernel.h>
1.1 cgd 47:
1.5 mycroft 48: #include <net/if.h>
49: #include <net/route.h>
1.1 cgd 50:
1.5 mycroft 51: #include <netinet/in.h>
52: #include <netinet/in_systm.h>
53: #include <netinet/ip.h>
54: #include <netinet/in_pcb.h>
55: #include <netinet/in_var.h>
56: #include <netinet/ip_var.h>
57: #include <netinet/ip_icmp.h>
1.8 mycroft 58: #include <netinet/ip_mroute.h>
1.1 cgd 59:
60: #ifndef IPFORWARDING
61: #ifdef GATEWAY
62: #define IPFORWARDING 1 /* forward IP packets not for us */
63: #else /* GATEWAY */
64: #define IPFORWARDING 0 /* don't forward IP packets not for us */
65: #endif /* GATEWAY */
66: #endif /* IPFORWARDING */
67: #ifndef IPSENDREDIRECTS
68: #define IPSENDREDIRECTS 1
69: #endif
70: int ipforwarding = IPFORWARDING;
71: int ipsendredirects = IPSENDREDIRECTS;
72: #ifdef DIAGNOSTIC
73: int ipprintfs = 0;
74: #endif
75:
76: extern struct domain inetdomain;
77: extern struct protosw inetsw[];
78: u_char ip_protox[IPPROTO_MAX];
79: int ipqmaxlen = IFQ_MAXLEN;
80: struct in_ifaddr *in_ifaddr; /* first inet address */
81:
82: /*
83: * We need to save the IP options in case a protocol wants to respond
84: * to an incoming packet over the same route if the packet got here
85: * using IP source routing. This allows connection establishment and
86: * maintenance when the remote end is on a network that is not known
87: * to us.
88: */
89: int ip_nhops = 0;
90: static struct ip_srcrt {
91: struct in_addr dst; /* final destination */
92: char nop; /* one NOP to align */
93: char srcopt[IPOPT_OFFSET + 1]; /* OPTVAL, OLEN and OFFSET */
94: struct in_addr route[MAX_IPOPTLEN/sizeof(struct in_addr)];
95: } ip_srcrt;
96:
97: #ifdef GATEWAY
98: extern int if_index;
99: u_long *ip_ifmatrix;
100: #endif
101:
1.8 mycroft 102: static void ip_forward __P((struct mbuf *, int));
103: static void save_rte __P((u_char *, struct in_addr));
104:
1.1 cgd 105: /*
106: * IP initialization: fill in IP protocol switch table.
107: * All protocols not implemented in kernel go to raw IP protocol handler.
108: */
1.8 mycroft 109: void
1.1 cgd 110: ip_init()
111: {
112: register struct protosw *pr;
113: register int i;
114:
115: pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW);
116: if (pr == 0)
117: panic("ip_init");
118: for (i = 0; i < IPPROTO_MAX; i++)
119: ip_protox[i] = pr - inetsw;
120: for (pr = inetdomain.dom_protosw;
121: pr < inetdomain.dom_protoswNPROTOSW; pr++)
122: if (pr->pr_domain->dom_family == PF_INET &&
123: pr->pr_protocol && pr->pr_protocol != IPPROTO_RAW)
124: ip_protox[pr->pr_protocol] = pr - inetsw;
125: ipq.next = ipq.prev = &ipq;
126: ip_id = time.tv_sec & 0xffff;
127: ipintrq.ifq_maxlen = ipqmaxlen;
128: #ifdef GATEWAY
129: i = (if_index + 1) * (if_index + 1) * sizeof (u_long);
130: if ((ip_ifmatrix = (u_long *) malloc(i, M_RTABLE, M_WAITOK)) == 0)
131: panic("no memory for ip_ifmatrix");
132: #endif
133: }
134:
135: struct ip *ip_reass();
136: struct sockaddr_in ipaddr = { sizeof(ipaddr), AF_INET };
137: struct route ipforward_rt;
138:
139: /*
140: * Ip input routine. Checksum and byte swap header. If fragmented
141: * try to reassemble. Process options. Pass to next level.
142: */
1.8 mycroft 143: void
1.1 cgd 144: ipintr()
145: {
146: register struct ip *ip;
147: register struct mbuf *m;
148: register struct ipq *fp;
149: register struct in_ifaddr *ia;
150: int hlen, s;
1.2 cgd 151: #ifdef PARANOID
152: static int busy = 0;
1.1 cgd 153:
1.2 cgd 154: if (busy)
155: panic("ipintr: called recursively\n");
156: ++busy;
157: #endif
1.1 cgd 158: next:
159: /*
160: * Get next datagram off input queue and get IP header
161: * in first mbuf.
162: */
163: s = splimp();
164: IF_DEQUEUE(&ipintrq, m);
165: splx(s);
1.2 cgd 166: if (m == 0) {
167: #ifdef PARANOID
168: --busy;
169: #endif
1.1 cgd 170: return;
1.2 cgd 171: }
1.1 cgd 172: #ifdef DIAGNOSTIC
173: if ((m->m_flags & M_PKTHDR) == 0)
174: panic("ipintr no HDR");
175: #endif
176: /*
177: * If no IP addresses have been set yet but the interfaces
178: * are receiving, can't do anything with incoming packets yet.
179: */
180: if (in_ifaddr == NULL)
181: goto bad;
182: ipstat.ips_total++;
183: if (m->m_len < sizeof (struct ip) &&
184: (m = m_pullup(m, sizeof (struct ip))) == 0) {
185: ipstat.ips_toosmall++;
186: goto next;
187: }
188: ip = mtod(m, struct ip *);
189: hlen = ip->ip_hl << 2;
190: if (hlen < sizeof(struct ip)) { /* minimum header length */
191: ipstat.ips_badhlen++;
192: goto bad;
193: }
194: if (hlen > m->m_len) {
195: if ((m = m_pullup(m, hlen)) == 0) {
196: ipstat.ips_badhlen++;
197: goto next;
198: }
199: ip = mtod(m, struct ip *);
200: }
201: if (ip->ip_sum = in_cksum(m, hlen)) {
202: ipstat.ips_badsum++;
203: goto bad;
204: }
205:
206: /*
207: * Convert fields to host representation.
208: */
209: NTOHS(ip->ip_len);
210: if (ip->ip_len < hlen) {
211: ipstat.ips_badlen++;
212: goto bad;
213: }
214: NTOHS(ip->ip_id);
215: NTOHS(ip->ip_off);
216:
217: /*
218: * Check that the amount of data in the buffers
219: * is as at least much as the IP header would have us expect.
220: * Trim mbufs if longer than we expect.
221: * Drop packet if shorter than we expect.
222: */
223: if (m->m_pkthdr.len < ip->ip_len) {
224: ipstat.ips_tooshort++;
225: goto bad;
226: }
227: if (m->m_pkthdr.len > ip->ip_len) {
228: if (m->m_len == m->m_pkthdr.len) {
229: m->m_len = ip->ip_len;
230: m->m_pkthdr.len = ip->ip_len;
231: } else
232: m_adj(m, ip->ip_len - m->m_pkthdr.len);
233: }
234:
235: /*
236: * Process options and, if not destined for us,
237: * ship it on. ip_dooptions returns 1 when an
238: * error was detected (causing an icmp message
239: * to be sent and the original packet to be freed).
240: */
241: ip_nhops = 0; /* for source routed packets */
242: if (hlen > sizeof (struct ip) && ip_dooptions(m))
243: goto next;
244:
245: /*
246: * Check our list of addresses, to see if the packet is for us.
247: */
248: for (ia = in_ifaddr; ia; ia = ia->ia_next) {
249: #define satosin(sa) ((struct sockaddr_in *)(sa))
250:
251: if (IA_SIN(ia)->sin_addr.s_addr == ip->ip_dst.s_addr)
252: goto ours;
253: if (
254: #ifdef DIRECTED_BROADCAST
255: ia->ia_ifp == m->m_pkthdr.rcvif &&
256: #endif
257: (ia->ia_ifp->if_flags & IFF_BROADCAST)) {
258: u_long t;
259:
260: if (satosin(&ia->ia_broadaddr)->sin_addr.s_addr ==
261: ip->ip_dst.s_addr)
262: goto ours;
263: if (ip->ip_dst.s_addr == ia->ia_netbroadcast.s_addr)
264: goto ours;
265: /*
266: * Look for all-0's host part (old broadcast addr),
267: * either for subnet or net.
268: */
269: t = ntohl(ip->ip_dst.s_addr);
270: if (t == ia->ia_subnet)
271: goto ours;
272: if (t == ia->ia_net)
273: goto ours;
274: }
275: }
1.4 hpeyerl 276: #ifdef MULTICAST
277: if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) {
278: struct in_multi *inm;
279: #ifdef MROUTING
280: extern struct socket *ip_mrouter;
1.10 ! brezak 281:
! 282: if (m->m_flags & M_EXT) {
! 283: if ((m = m_pullup(m, hlen)) == 0) {
! 284: ipstat.ips_toosmall++;
! 285: goto next;
! 286: }
! 287: ip = mtod(m, struct ip *);
! 288: }
1.4 hpeyerl 289:
290: if (ip_mrouter) {
291: /*
292: * If we are acting as a multicast router, all
293: * incoming multicast packets are passed to the
294: * kernel-level multicast forwarding function.
295: * The packet is returned (relatively) intact; if
296: * ip_mforward() returns a non-zero value, the packet
297: * must be discarded, else it may be accepted below.
298: *
299: * (The IP ident field is put in the same byte order
300: * as expected when ip_mforward() is called from
301: * ip_output().)
302: */
303: ip->ip_id = htons(ip->ip_id);
304: if (ip_mforward(ip, m->m_pkthdr.rcvif, m) != 0) {
305: m_freem(m);
306: goto next;
307: }
308: ip->ip_id = ntohs(ip->ip_id);
309:
310: /*
311: * The process-level routing demon needs to receive
312: * all multicast IGMP packets, whether or not this
313: * host belongs to their destination groups.
314: */
315: if (ip->ip_p == IPPROTO_IGMP)
316: goto ours;
317: }
318: #endif
319: /*
320: * See if we belong to the destination multicast group on the
321: * arrival interface.
322: */
323: IN_LOOKUP_MULTI(ip->ip_dst, m->m_pkthdr.rcvif, inm);
324: if (inm == NULL) {
325: m_freem(m);
326: goto next;
327: }
328: goto ours;
329: }
330: #endif
1.1 cgd 331: if (ip->ip_dst.s_addr == (u_long)INADDR_BROADCAST)
332: goto ours;
333: if (ip->ip_dst.s_addr == INADDR_ANY)
334: goto ours;
335:
336: /*
337: * Not for us; forward if possible and desirable.
338: */
339: if (ipforwarding == 0) {
340: ipstat.ips_cantforward++;
341: m_freem(m);
342: } else
343: ip_forward(m, 0);
344: goto next;
345:
346: ours:
347: /*
348: * If offset or IP_MF are set, must reassemble.
349: * Otherwise, nothing need be done.
350: * (We could look in the reassembly queue to see
351: * if the packet was previously fragmented,
352: * but it's not worth the time; just let them time out.)
353: */
354: if (ip->ip_off &~ IP_DF) {
355: if (m->m_flags & M_EXT) { /* XXX */
356: if ((m = m_pullup(m, sizeof (struct ip))) == 0) {
357: ipstat.ips_toosmall++;
358: goto next;
359: }
360: ip = mtod(m, struct ip *);
361: }
362: /*
363: * Look for queue of fragments
364: * of this datagram.
365: */
366: for (fp = ipq.next; fp != &ipq; fp = fp->next)
367: if (ip->ip_id == fp->ipq_id &&
368: ip->ip_src.s_addr == fp->ipq_src.s_addr &&
369: ip->ip_dst.s_addr == fp->ipq_dst.s_addr &&
370: ip->ip_p == fp->ipq_p)
371: goto found;
372: fp = 0;
373: found:
374:
375: /*
376: * Adjust ip_len to not reflect header,
377: * set ip_mff if more fragments are expected,
378: * convert offset of this to bytes.
379: */
380: ip->ip_len -= hlen;
381: ((struct ipasfrag *)ip)->ipf_mff = 0;
382: if (ip->ip_off & IP_MF)
383: ((struct ipasfrag *)ip)->ipf_mff = 1;
384: ip->ip_off <<= 3;
385:
386: /*
387: * If datagram marked as having more fragments
388: * or if this is not the first fragment,
389: * attempt reassembly; if it succeeds, proceed.
390: */
391: if (((struct ipasfrag *)ip)->ipf_mff || ip->ip_off) {
392: ipstat.ips_fragments++;
393: ip = ip_reass((struct ipasfrag *)ip, fp);
394: if (ip == 0)
395: goto next;
396: else
397: ipstat.ips_reassembled++;
398: m = dtom(ip);
399: } else
400: if (fp)
401: ip_freef(fp);
402: } else
403: ip->ip_len -= hlen;
404:
405: /*
406: * Switch out to protocol's input routine.
407: */
408: ipstat.ips_delivered++;
409: (*inetsw[ip_protox[ip->ip_p]].pr_input)(m, hlen);
410: goto next;
411: bad:
412: m_freem(m);
413: goto next;
414: }
415:
416: /*
417: * Take incoming datagram fragment and try to
418: * reassemble it into whole datagram. If a chain for
419: * reassembly of this datagram already exists, then it
420: * is given as fp; otherwise have to make a chain.
421: */
422: struct ip *
423: ip_reass(ip, fp)
424: register struct ipasfrag *ip;
425: register struct ipq *fp;
426: {
427: register struct mbuf *m = dtom(ip);
428: register struct ipasfrag *q;
429: struct mbuf *t;
430: int hlen = ip->ip_hl << 2;
431: int i, next;
432:
433: /*
434: * Presence of header sizes in mbufs
435: * would confuse code below.
436: */
437: m->m_data += hlen;
438: m->m_len -= hlen;
439:
440: /*
441: * If first fragment to arrive, create a reassembly queue.
442: */
443: if (fp == 0) {
444: if ((t = m_get(M_DONTWAIT, MT_FTABLE)) == NULL)
445: goto dropfrag;
446: fp = mtod(t, struct ipq *);
447: insque(fp, &ipq);
448: fp->ipq_ttl = IPFRAGTTL;
449: fp->ipq_p = ip->ip_p;
450: fp->ipq_id = ip->ip_id;
451: fp->ipq_next = fp->ipq_prev = (struct ipasfrag *)fp;
452: fp->ipq_src = ((struct ip *)ip)->ip_src;
453: fp->ipq_dst = ((struct ip *)ip)->ip_dst;
454: q = (struct ipasfrag *)fp;
455: goto insert;
456: }
457:
458: /*
459: * Find a segment which begins after this one does.
460: */
461: for (q = fp->ipq_next; q != (struct ipasfrag *)fp; q = q->ipf_next)
462: if (q->ip_off > ip->ip_off)
463: break;
464:
465: /*
466: * If there is a preceding segment, it may provide some of
467: * our data already. If so, drop the data from the incoming
468: * segment. If it provides all of our data, drop us.
469: */
470: if (q->ipf_prev != (struct ipasfrag *)fp) {
471: i = q->ipf_prev->ip_off + q->ipf_prev->ip_len - ip->ip_off;
472: if (i > 0) {
473: if (i >= ip->ip_len)
474: goto dropfrag;
475: m_adj(dtom(ip), i);
476: ip->ip_off += i;
477: ip->ip_len -= i;
478: }
479: }
480:
481: /*
482: * While we overlap succeeding segments trim them or,
483: * if they are completely covered, dequeue them.
484: */
485: while (q != (struct ipasfrag *)fp && ip->ip_off + ip->ip_len > q->ip_off) {
486: i = (ip->ip_off + ip->ip_len) - q->ip_off;
487: if (i < q->ip_len) {
488: q->ip_len -= i;
489: q->ip_off += i;
490: m_adj(dtom(q), i);
491: break;
492: }
493: q = q->ipf_next;
494: m_freem(dtom(q->ipf_prev));
495: ip_deq(q->ipf_prev);
496: }
497:
498: insert:
499: /*
500: * Stick new segment in its place;
501: * check for complete reassembly.
502: */
503: ip_enq(ip, q->ipf_prev);
504: next = 0;
505: for (q = fp->ipq_next; q != (struct ipasfrag *)fp; q = q->ipf_next) {
506: if (q->ip_off != next)
507: return (0);
508: next += q->ip_len;
509: }
510: if (q->ipf_prev->ipf_mff)
511: return (0);
512:
513: /*
514: * Reassembly is complete; concatenate fragments.
515: */
516: q = fp->ipq_next;
517: m = dtom(q);
518: t = m->m_next;
519: m->m_next = 0;
520: m_cat(m, t);
521: q = q->ipf_next;
522: while (q != (struct ipasfrag *)fp) {
523: t = dtom(q);
524: q = q->ipf_next;
525: m_cat(m, t);
526: }
527:
528: /*
529: * Create header for new ip packet by
530: * modifying header of first packet;
531: * dequeue and discard fragment reassembly header.
532: * Make header visible.
533: */
534: ip = fp->ipq_next;
535: ip->ip_len = next;
536: ((struct ip *)ip)->ip_src = fp->ipq_src;
537: ((struct ip *)ip)->ip_dst = fp->ipq_dst;
538: remque(fp);
539: (void) m_free(dtom(fp));
540: m = dtom(ip);
541: m->m_len += (ip->ip_hl << 2);
542: m->m_data -= (ip->ip_hl << 2);
543: /* some debugging cruft by sklower, below, will go away soon */
544: if (m->m_flags & M_PKTHDR) { /* XXX this should be done elsewhere */
545: register int plen = 0;
546: for (t = m; m; m = m->m_next)
547: plen += m->m_len;
548: t->m_pkthdr.len = plen;
549: }
550: return ((struct ip *)ip);
551:
552: dropfrag:
553: ipstat.ips_fragdropped++;
554: m_freem(m);
555: return (0);
556: }
557:
558: /*
559: * Free a fragment reassembly header and all
560: * associated datagrams.
561: */
1.8 mycroft 562: void
1.1 cgd 563: ip_freef(fp)
564: struct ipq *fp;
565: {
566: register struct ipasfrag *q, *p;
567:
568: for (q = fp->ipq_next; q != (struct ipasfrag *)fp; q = p) {
569: p = q->ipf_next;
570: ip_deq(q);
571: m_freem(dtom(q));
572: }
573: remque(fp);
574: (void) m_free(dtom(fp));
575: }
576:
577: /*
578: * Put an ip fragment on a reassembly chain.
579: * Like insque, but pointers in middle of structure.
580: */
1.8 mycroft 581: void
1.1 cgd 582: ip_enq(p, prev)
583: register struct ipasfrag *p, *prev;
584: {
585:
586: p->ipf_prev = prev;
587: p->ipf_next = prev->ipf_next;
588: prev->ipf_next->ipf_prev = p;
589: prev->ipf_next = p;
590: }
591:
592: /*
593: * To ip_enq as remque is to insque.
594: */
1.8 mycroft 595: void
1.1 cgd 596: ip_deq(p)
597: register struct ipasfrag *p;
598: {
599:
600: p->ipf_prev->ipf_next = p->ipf_next;
601: p->ipf_next->ipf_prev = p->ipf_prev;
602: }
603:
604: /*
605: * IP timer processing;
606: * if a timer expires on a reassembly
607: * queue, discard it.
608: */
1.8 mycroft 609: void
1.1 cgd 610: ip_slowtimo()
611: {
612: register struct ipq *fp;
613: int s = splnet();
614:
615: fp = ipq.next;
616: if (fp == 0) {
617: splx(s);
618: return;
619: }
620: while (fp != &ipq) {
621: --fp->ipq_ttl;
622: fp = fp->next;
623: if (fp->prev->ipq_ttl == 0) {
624: ipstat.ips_fragtimeout++;
625: ip_freef(fp->prev);
626: }
627: }
628: splx(s);
629: }
630:
631: /*
632: * Drain off all datagram fragments.
633: */
1.8 mycroft 634: void
1.1 cgd 635: ip_drain()
636: {
637:
638: while (ipq.next != &ipq) {
639: ipstat.ips_fragdropped++;
640: ip_freef(ipq.next);
641: }
642: }
643:
644: extern struct in_ifaddr *ifptoia();
645: struct in_ifaddr *ip_rtaddr();
646:
647: /*
648: * Do option processing on a datagram,
649: * possibly discarding it if bad options are encountered,
650: * or forwarding it if source-routed.
651: * Returns 1 if packet has been forwarded/freed,
652: * 0 if the packet should be processed further.
653: */
1.8 mycroft 654: int
1.1 cgd 655: ip_dooptions(m)
656: struct mbuf *m;
657: {
658: register struct ip *ip = mtod(m, struct ip *);
659: register u_char *cp;
660: register struct ip_timestamp *ipt;
661: register struct in_ifaddr *ia;
662: int opt, optlen, cnt, off, code, type = ICMP_PARAMPROB, forward = 0;
663: struct in_addr *sin;
664: n_time ntime;
665:
666: cp = (u_char *)(ip + 1);
667: cnt = (ip->ip_hl << 2) - sizeof (struct ip);
668: for (; cnt > 0; cnt -= optlen, cp += optlen) {
669: opt = cp[IPOPT_OPTVAL];
670: if (opt == IPOPT_EOL)
671: break;
672: if (opt == IPOPT_NOP)
673: optlen = 1;
674: else {
675: optlen = cp[IPOPT_OLEN];
676: if (optlen <= 0 || optlen > cnt) {
677: code = &cp[IPOPT_OLEN] - (u_char *)ip;
678: goto bad;
679: }
680: }
681: switch (opt) {
682:
683: default:
684: break;
685:
686: /*
687: * Source routing with record.
688: * Find interface with current destination address.
689: * If none on this machine then drop if strictly routed,
690: * or do nothing if loosely routed.
691: * Record interface address and bring up next address
692: * component. If strictly routed make sure next
693: * address is on directly accessible net.
694: */
695: case IPOPT_LSRR:
696: case IPOPT_SSRR:
697: if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) {
698: code = &cp[IPOPT_OFFSET] - (u_char *)ip;
699: goto bad;
700: }
701: ipaddr.sin_addr = ip->ip_dst;
702: ia = (struct in_ifaddr *)
703: ifa_ifwithaddr((struct sockaddr *)&ipaddr);
704: if (ia == 0) {
705: if (opt == IPOPT_SSRR) {
706: type = ICMP_UNREACH;
707: code = ICMP_UNREACH_SRCFAIL;
708: goto bad;
709: }
710: /*
711: * Loose routing, and not at next destination
712: * yet; nothing to do except forward.
713: */
714: break;
715: }
716: off--; /* 0 origin */
717: if (off > optlen - sizeof(struct in_addr)) {
718: /*
719: * End of source route. Should be for us.
720: */
721: save_rte(cp, ip->ip_src);
722: break;
723: }
724: /*
725: * locate outgoing interface
726: */
727: bcopy((caddr_t)(cp + off), (caddr_t)&ipaddr.sin_addr,
728: sizeof(ipaddr.sin_addr));
729: if (opt == IPOPT_SSRR) {
730: #define INA struct in_ifaddr *
731: #define SA struct sockaddr *
732: if ((ia = (INA)ifa_ifwithdstaddr((SA)&ipaddr)) == 0)
733: ia = in_iaonnetof(in_netof(ipaddr.sin_addr));
734: } else
735: ia = ip_rtaddr(ipaddr.sin_addr);
736: if (ia == 0) {
737: type = ICMP_UNREACH;
738: code = ICMP_UNREACH_SRCFAIL;
739: goto bad;
740: }
741: ip->ip_dst = ipaddr.sin_addr;
742: bcopy((caddr_t)&(IA_SIN(ia)->sin_addr),
743: (caddr_t)(cp + off), sizeof(struct in_addr));
744: cp[IPOPT_OFFSET] += sizeof(struct in_addr);
745: forward = 1;
746: break;
747:
748: case IPOPT_RR:
749: if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) {
750: code = &cp[IPOPT_OFFSET] - (u_char *)ip;
751: goto bad;
752: }
753: /*
754: * If no space remains, ignore.
755: */
756: off--; /* 0 origin */
757: if (off > optlen - sizeof(struct in_addr))
758: break;
759: bcopy((caddr_t)(&ip->ip_dst), (caddr_t)&ipaddr.sin_addr,
760: sizeof(ipaddr.sin_addr));
761: /*
762: * locate outgoing interface; if we're the destination,
763: * use the incoming interface (should be same).
764: */
765: if ((ia = (INA)ifa_ifwithaddr((SA)&ipaddr)) == 0 &&
766: (ia = ip_rtaddr(ipaddr.sin_addr)) == 0) {
767: type = ICMP_UNREACH;
768: code = ICMP_UNREACH_HOST;
769: goto bad;
770: }
771: bcopy((caddr_t)&(IA_SIN(ia)->sin_addr),
772: (caddr_t)(cp + off), sizeof(struct in_addr));
773: cp[IPOPT_OFFSET] += sizeof(struct in_addr);
774: break;
775:
776: case IPOPT_TS:
777: code = cp - (u_char *)ip;
778: ipt = (struct ip_timestamp *)cp;
779: if (ipt->ipt_len < 5)
780: goto bad;
781: if (ipt->ipt_ptr > ipt->ipt_len - sizeof (long)) {
782: if (++ipt->ipt_oflw == 0)
783: goto bad;
784: break;
785: }
786: sin = (struct in_addr *)(cp + ipt->ipt_ptr - 1);
787: switch (ipt->ipt_flg) {
788:
789: case IPOPT_TS_TSONLY:
790: break;
791:
792: case IPOPT_TS_TSANDADDR:
793: if (ipt->ipt_ptr + sizeof(n_time) +
794: sizeof(struct in_addr) > ipt->ipt_len)
795: goto bad;
796: ia = ifptoia(m->m_pkthdr.rcvif);
797: bcopy((caddr_t)&IA_SIN(ia)->sin_addr,
798: (caddr_t)sin, sizeof(struct in_addr));
799: ipt->ipt_ptr += sizeof(struct in_addr);
800: break;
801:
802: case IPOPT_TS_PRESPEC:
803: if (ipt->ipt_ptr + sizeof(n_time) +
804: sizeof(struct in_addr) > ipt->ipt_len)
805: goto bad;
806: bcopy((caddr_t)sin, (caddr_t)&ipaddr.sin_addr,
807: sizeof(struct in_addr));
808: if (ifa_ifwithaddr((SA)&ipaddr) == 0)
809: continue;
810: ipt->ipt_ptr += sizeof(struct in_addr);
811: break;
812:
813: default:
814: goto bad;
815: }
816: ntime = iptime();
817: bcopy((caddr_t)&ntime, (caddr_t)cp + ipt->ipt_ptr - 1,
818: sizeof(n_time));
819: ipt->ipt_ptr += sizeof(n_time);
820: }
821: }
822: if (forward) {
823: ip_forward(m, 1);
824: return (1);
825: } else
826: return (0);
827: bad:
1.7 mycroft 828: {
829: register struct in_addr foo = {};
830: icmp_error(m, type, code, foo);
831: }
1.1 cgd 832: return (1);
833: }
834:
835: /*
836: * Given address of next destination (final or next hop),
837: * return internet address info of interface to be used to get there.
838: */
839: struct in_ifaddr *
840: ip_rtaddr(dst)
841: struct in_addr dst;
842: {
843: register struct sockaddr_in *sin;
844:
845: sin = (struct sockaddr_in *) &ipforward_rt.ro_dst;
846:
847: if (ipforward_rt.ro_rt == 0 || dst.s_addr != sin->sin_addr.s_addr) {
848: if (ipforward_rt.ro_rt) {
849: RTFREE(ipforward_rt.ro_rt);
850: ipforward_rt.ro_rt = 0;
851: }
852: sin->sin_family = AF_INET;
853: sin->sin_len = sizeof(*sin);
854: sin->sin_addr = dst;
855:
856: rtalloc(&ipforward_rt);
857: }
858: if (ipforward_rt.ro_rt == 0)
859: return ((struct in_ifaddr *)0);
860: return ((struct in_ifaddr *) ipforward_rt.ro_rt->rt_ifa);
861: }
862:
863: /*
864: * Save incoming source route for use in replies,
865: * to be picked up later by ip_srcroute if the receiver is interested.
866: */
1.8 mycroft 867: static void
1.1 cgd 868: save_rte(option, dst)
869: u_char *option;
870: struct in_addr dst;
871: {
872: unsigned olen;
873:
874: olen = option[IPOPT_OLEN];
875: #ifdef DIAGNOSTIC
876: if (ipprintfs)
877: printf("save_rte: olen %d\n", olen);
878: #endif
879: if (olen > sizeof(ip_srcrt) - (1 + sizeof(dst)))
880: return;
881: bcopy((caddr_t)option, (caddr_t)ip_srcrt.srcopt, olen);
882: ip_nhops = (olen - IPOPT_OFFSET - 1) / sizeof(struct in_addr);
883: ip_srcrt.dst = dst;
884: }
885:
886: /*
887: * Retrieve incoming source route for use in replies,
888: * in the same form used by setsockopt.
889: * The first hop is placed before the options, will be removed later.
890: */
891: struct mbuf *
892: ip_srcroute()
893: {
894: register struct in_addr *p, *q;
895: register struct mbuf *m;
896:
897: if (ip_nhops == 0)
898: return ((struct mbuf *)0);
899: m = m_get(M_DONTWAIT, MT_SOOPTS);
900: if (m == 0)
901: return ((struct mbuf *)0);
902:
1.6 mycroft 903: #define OPTSIZ (sizeof(ip_srcrt.nop) + sizeof(ip_srcrt.srcopt))
1.1 cgd 904:
905: /* length is (nhops+1)*sizeof(addr) + sizeof(nop + srcrt header) */
906: m->m_len = ip_nhops * sizeof(struct in_addr) + sizeof(struct in_addr) +
907: OPTSIZ;
908: #ifdef DIAGNOSTIC
909: if (ipprintfs)
910: printf("ip_srcroute: nhops %d mlen %d", ip_nhops, m->m_len);
911: #endif
912:
913: /*
914: * First save first hop for return route
915: */
916: p = &ip_srcrt.route[ip_nhops - 1];
917: *(mtod(m, struct in_addr *)) = *p--;
918: #ifdef DIAGNOSTIC
919: if (ipprintfs)
920: printf(" hops %lx", ntohl(mtod(m, struct in_addr *)->s_addr));
921: #endif
922:
923: /*
924: * Copy option fields and padding (nop) to mbuf.
925: */
926: ip_srcrt.nop = IPOPT_NOP;
927: ip_srcrt.srcopt[IPOPT_OFFSET] = IPOPT_MINOFF;
928: bcopy((caddr_t)&ip_srcrt.nop,
929: mtod(m, caddr_t) + sizeof(struct in_addr), OPTSIZ);
930: q = (struct in_addr *)(mtod(m, caddr_t) +
931: sizeof(struct in_addr) + OPTSIZ);
932: #undef OPTSIZ
933: /*
934: * Record return path as an IP source route,
935: * reversing the path (pointers are now aligned).
936: */
937: while (p >= ip_srcrt.route) {
938: #ifdef DIAGNOSTIC
939: if (ipprintfs)
940: printf(" %lx", ntohl(q->s_addr));
941: #endif
942: *q++ = *p--;
943: }
944: /*
945: * Last hop goes to final destination.
946: */
947: *q = ip_srcrt.dst;
948: #ifdef DIAGNOSTIC
949: if (ipprintfs)
950: printf(" %lx\n", ntohl(q->s_addr));
951: #endif
952: return (m);
953: }
954:
955: /*
956: * Strip out IP options, at higher
957: * level protocol in the kernel.
958: * Second argument is buffer to which options
959: * will be moved, and return value is their length.
960: * XXX should be deleted; last arg currently ignored.
961: */
1.8 mycroft 962: void
1.1 cgd 963: ip_stripoptions(m, mopt)
964: register struct mbuf *m;
965: struct mbuf *mopt;
966: {
967: register int i;
968: struct ip *ip = mtod(m, struct ip *);
969: register caddr_t opts;
970: int olen;
971:
972: olen = (ip->ip_hl<<2) - sizeof (struct ip);
973: opts = (caddr_t)(ip + 1);
974: i = m->m_len - (sizeof (struct ip) + olen);
975: bcopy(opts + olen, opts, (unsigned)i);
976: m->m_len -= olen;
977: if (m->m_flags & M_PKTHDR)
978: m->m_pkthdr.len -= olen;
979: ip->ip_hl = sizeof(struct ip) >> 2;
980: }
981:
982: u_char inetctlerrmap[PRC_NCMDS] = {
983: 0, 0, 0, 0,
984: 0, EMSGSIZE, EHOSTDOWN, EHOSTUNREACH,
985: EHOSTUNREACH, EHOSTUNREACH, ECONNREFUSED, ECONNREFUSED,
986: EMSGSIZE, EHOSTUNREACH, 0, 0,
987: 0, 0, 0, 0,
988: ENOPROTOOPT
989: };
990:
991: /*
992: * Forward a packet. If some error occurs return the sender
993: * an icmp packet. Note we can't always generate a meaningful
994: * icmp message because icmp doesn't have a large enough repertoire
995: * of codes and types.
996: *
997: * If not forwarding, just drop the packet. This could be confusing
998: * if ipforwarding was zero but some routing protocol was advancing
999: * us as a gateway to somewhere. However, we must let the routing
1000: * protocol deal with that.
1001: *
1002: * The srcrt parameter indicates whether the packet is being forwarded
1003: * via a source route.
1004: */
1.8 mycroft 1005: static void
1.1 cgd 1006: ip_forward(m, srcrt)
1007: struct mbuf *m;
1008: int srcrt;
1009: {
1010: register struct ip *ip = mtod(m, struct ip *);
1011: register struct sockaddr_in *sin;
1012: register struct rtentry *rt;
1013: int error, type = 0, code;
1014: struct mbuf *mcopy;
1015: struct in_addr dest;
1016:
1017: dest.s_addr = 0;
1018: #ifdef DIAGNOSTIC
1019: if (ipprintfs)
1020: printf("forward: src %x dst %x ttl %x\n", ip->ip_src,
1021: ip->ip_dst, ip->ip_ttl);
1022: #endif
1023: if (m->m_flags & M_BCAST || in_canforward(ip->ip_dst) == 0) {
1024: ipstat.ips_cantforward++;
1025: m_freem(m);
1026: return;
1027: }
1028: HTONS(ip->ip_id);
1029: if (ip->ip_ttl <= IPTTLDEC) {
1030: icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, dest);
1031: return;
1032: }
1033: ip->ip_ttl -= IPTTLDEC;
1034:
1035: sin = (struct sockaddr_in *)&ipforward_rt.ro_dst;
1036: if ((rt = ipforward_rt.ro_rt) == 0 ||
1037: ip->ip_dst.s_addr != sin->sin_addr.s_addr) {
1038: if (ipforward_rt.ro_rt) {
1039: RTFREE(ipforward_rt.ro_rt);
1040: ipforward_rt.ro_rt = 0;
1041: }
1042: sin->sin_family = AF_INET;
1043: sin->sin_len = sizeof(*sin);
1044: sin->sin_addr = ip->ip_dst;
1045:
1046: rtalloc(&ipforward_rt);
1047: if (ipforward_rt.ro_rt == 0) {
1048: icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, dest);
1049: return;
1050: }
1051: rt = ipforward_rt.ro_rt;
1052: }
1053:
1054: /*
1055: * Save at most 64 bytes of the packet in case
1056: * we need to generate an ICMP message to the src.
1057: */
1058: mcopy = m_copy(m, 0, imin((int)ip->ip_len, 64));
1059:
1060: #ifdef GATEWAY
1061: ip_ifmatrix[rt->rt_ifp->if_index +
1062: if_index * m->m_pkthdr.rcvif->if_index]++;
1063: #endif
1064: /*
1065: * If forwarding packet using same interface that it came in on,
1066: * perhaps should send a redirect to sender to shortcut a hop.
1067: * Only send redirect if source is sending directly to us,
1068: * and if packet was not source routed (or has any options).
1069: * Also, don't send redirect if forwarding using a default route
1070: * or a route modified by a redirect.
1071: */
1072: #define satosin(sa) ((struct sockaddr_in *)(sa))
1073: if (rt->rt_ifp == m->m_pkthdr.rcvif &&
1074: (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0 &&
1075: satosin(rt_key(rt))->sin_addr.s_addr != 0 &&
1076: ipsendredirects && !srcrt) {
1077: struct in_ifaddr *ia;
1078: u_long src = ntohl(ip->ip_src.s_addr);
1079: u_long dst = ntohl(ip->ip_dst.s_addr);
1080:
1081: if ((ia = ifptoia(m->m_pkthdr.rcvif)) &&
1082: (src & ia->ia_subnetmask) == ia->ia_subnet) {
1083: if (rt->rt_flags & RTF_GATEWAY)
1084: dest = satosin(rt->rt_gateway)->sin_addr;
1085: else
1086: dest = ip->ip_dst;
1087: /*
1088: * If the destination is reached by a route to host,
1089: * is on a subnet of a local net, or is directly
1090: * on the attached net (!), use host redirect.
1091: * (We may be the correct first hop for other subnets.)
1092: */
1093: #define RTA(rt) ((struct in_ifaddr *)(rt->rt_ifa))
1094: type = ICMP_REDIRECT;
1095: if ((rt->rt_flags & RTF_HOST) ||
1096: (rt->rt_flags & RTF_GATEWAY) == 0)
1097: code = ICMP_REDIRECT_HOST;
1098: else if (RTA(rt)->ia_subnetmask != RTA(rt)->ia_netmask &&
1099: (dst & RTA(rt)->ia_netmask) == RTA(rt)->ia_net)
1100: code = ICMP_REDIRECT_HOST;
1101: else
1102: code = ICMP_REDIRECT_NET;
1103: #ifdef DIAGNOSTIC
1104: if (ipprintfs)
1105: printf("redirect (%d) to %x\n", code, dest.s_addr);
1106: #endif
1107: }
1108: }
1109:
1.9 mycroft 1110: error = ip_output(m, NULL, &ipforward_rt, IP_FORWARDING
1111: #ifdef DIRECTED_BROADCAST
1112: | IP_ALLOWBROADCAST
1113: #endif
1114: , NULL);
1.1 cgd 1115: if (error)
1116: ipstat.ips_cantforward++;
1117: else {
1118: ipstat.ips_forward++;
1119: if (type)
1120: ipstat.ips_redirectsent++;
1121: else {
1122: if (mcopy)
1123: m_freem(mcopy);
1124: return;
1125: }
1126: }
1127: if (mcopy == NULL)
1128: return;
1129: switch (error) {
1130:
1131: case 0: /* forwarded, but need redirect */
1132: /* type, code set above */
1133: break;
1134:
1135: case ENETUNREACH: /* shouldn't happen, checked above */
1136: case EHOSTUNREACH:
1137: case ENETDOWN:
1138: case EHOSTDOWN:
1139: default:
1140: type = ICMP_UNREACH;
1141: code = ICMP_UNREACH_HOST;
1142: break;
1143:
1144: case EMSGSIZE:
1145: type = ICMP_UNREACH;
1146: code = ICMP_UNREACH_NEEDFRAG;
1147: ipstat.ips_cantfrag++;
1148: break;
1149:
1150: case ENOBUFS:
1151: type = ICMP_SOURCEQUENCH;
1152: code = 0;
1153: break;
1154: }
1155: icmp_error(mcopy, type, code, dest);
1156: }