Annotation of src/sys/netinet/ip_input.c, Revision 1.30.4.1
1.30.4.1! thorpej 1: /* $NetBSD: ip_input.c,v 1.30 1996/03/16 23:53:58 christos Exp $ */
1.14 cgd 2:
1.1 cgd 3: /*
1.13 mycroft 4: * Copyright (c) 1982, 1986, 1988, 1993
5: * The Regents of the University of California. All rights reserved.
1.1 cgd 6: *
7: * Redistribution and use in source and binary forms, with or without
8: * modification, are permitted provided that the following conditions
9: * are met:
10: * 1. Redistributions of source code must retain the above copyright
11: * notice, this list of conditions and the following disclaimer.
12: * 2. Redistributions in binary form must reproduce the above copyright
13: * notice, this list of conditions and the following disclaimer in the
14: * documentation and/or other materials provided with the distribution.
15: * 3. All advertising materials mentioning features or use of this software
16: * must display the following acknowledgement:
17: * This product includes software developed by the University of
18: * California, Berkeley and its contributors.
19: * 4. Neither the name of the University nor the names of its contributors
20: * may be used to endorse or promote products derived from this software
21: * without specific prior written permission.
22: *
23: * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24: * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25: * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26: * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27: * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28: * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29: * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30: * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31: * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32: * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33: * SUCH DAMAGE.
34: *
1.14 cgd 35: * @(#)ip_input.c 8.2 (Berkeley) 1/4/94
1.1 cgd 36: */
37:
1.5 mycroft 38: #include <sys/param.h>
39: #include <sys/systm.h>
40: #include <sys/malloc.h>
41: #include <sys/mbuf.h>
42: #include <sys/domain.h>
43: #include <sys/protosw.h>
44: #include <sys/socket.h>
45: #include <sys/errno.h>
46: #include <sys/time.h>
47: #include <sys/kernel.h>
1.28 christos 48: #include <sys/proc.h>
49:
50: #include <vm/vm.h>
51: #include <sys/sysctl.h>
1.1 cgd 52:
1.5 mycroft 53: #include <net/if.h>
54: #include <net/route.h>
1.1 cgd 55:
1.5 mycroft 56: #include <netinet/in.h>
57: #include <netinet/in_systm.h>
58: #include <netinet/ip.h>
59: #include <netinet/in_pcb.h>
60: #include <netinet/in_var.h>
61: #include <netinet/ip_var.h>
62: #include <netinet/ip_icmp.h>
1.1 cgd 63:
64: #ifndef IPFORWARDING
65: #ifdef GATEWAY
66: #define IPFORWARDING 1 /* forward IP packets not for us */
67: #else /* GATEWAY */
68: #define IPFORWARDING 0 /* don't forward IP packets not for us */
69: #endif /* GATEWAY */
70: #endif /* IPFORWARDING */
71: #ifndef IPSENDREDIRECTS
72: #define IPSENDREDIRECTS 1
73: #endif
1.26 thorpej 74: #ifndef IPFORWSRCRT
75: #define IPFORWSRCRT 1 /* allow source-routed packets */
76: #endif
1.27 thorpej 77: /*
78: * Note: DIRECTED_BROADCAST is handled this way so that previous
79: * configuration using this option will Just Work.
80: */
81: #ifndef IPDIRECTEDBCAST
82: #ifdef DIRECTED_BROADCAST
83: #define IPDIRECTEDBCAST 1
84: #else
85: #define IPDIRECTEDBCAST 0
86: #endif /* DIRECTED_BROADCAST */
87: #endif /* IPDIRECTEDBCAST */
1.1 cgd 88: int ipforwarding = IPFORWARDING;
89: int ipsendredirects = IPSENDREDIRECTS;
1.13 mycroft 90: int ip_defttl = IPDEFTTL;
1.26 thorpej 91: int ip_forwsrcrt = IPFORWSRCRT;
1.27 thorpej 92: int ip_directedbcast = IPDIRECTEDBCAST;
1.1 cgd 93: #ifdef DIAGNOSTIC
94: int ipprintfs = 0;
95: #endif
96:
97: extern struct domain inetdomain;
98: extern struct protosw inetsw[];
99: u_char ip_protox[IPPROTO_MAX];
100: int ipqmaxlen = IFQ_MAXLEN;
1.22 mycroft 101: struct in_ifaddrhead in_ifaddr;
1.13 mycroft 102: struct ifqueue ipintrq;
1.1 cgd 103:
104: /*
105: * We need to save the IP options in case a protocol wants to respond
106: * to an incoming packet over the same route if the packet got here
107: * using IP source routing. This allows connection establishment and
108: * maintenance when the remote end is on a network that is not known
109: * to us.
110: */
111: int ip_nhops = 0;
112: static struct ip_srcrt {
113: struct in_addr dst; /* final destination */
114: char nop; /* one NOP to align */
115: char srcopt[IPOPT_OFFSET + 1]; /* OPTVAL, OLEN and OFFSET */
116: struct in_addr route[MAX_IPOPTLEN/sizeof(struct in_addr)];
117: } ip_srcrt;
118:
1.13 mycroft 119: static void save_rte __P((u_char *, struct in_addr));
1.1 cgd 120: /*
121: * IP initialization: fill in IP protocol switch table.
122: * All protocols not implemented in kernel go to raw IP protocol handler.
123: */
1.8 mycroft 124: void
1.1 cgd 125: ip_init()
126: {
127: register struct protosw *pr;
128: register int i;
129:
130: pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW);
131: if (pr == 0)
132: panic("ip_init");
133: for (i = 0; i < IPPROTO_MAX; i++)
134: ip_protox[i] = pr - inetsw;
135: for (pr = inetdomain.dom_protosw;
136: pr < inetdomain.dom_protoswNPROTOSW; pr++)
137: if (pr->pr_domain->dom_family == PF_INET &&
138: pr->pr_protocol && pr->pr_protocol != IPPROTO_RAW)
139: ip_protox[pr->pr_protocol] = pr - inetsw;
1.25 cgd 140: LIST_INIT(&ipq);
1.1 cgd 141: ip_id = time.tv_sec & 0xffff;
142: ipintrq.ifq_maxlen = ipqmaxlen;
1.22 mycroft 143: TAILQ_INIT(&in_ifaddr);
1.1 cgd 144: }
145:
146: struct sockaddr_in ipaddr = { sizeof(ipaddr), AF_INET };
147: struct route ipforward_rt;
148:
149: /*
150: * Ip input routine. Checksum and byte swap header. If fragmented
151: * try to reassemble. Process options. Pass to next level.
152: */
1.8 mycroft 153: void
1.1 cgd 154: ipintr()
155: {
156: register struct ip *ip;
157: register struct mbuf *m;
158: register struct ipq *fp;
159: register struct in_ifaddr *ia;
1.25 cgd 160: struct ipqent *ipqe;
161: int hlen, mff, s;
1.1 cgd 162:
163: next:
164: /*
165: * Get next datagram off input queue and get IP header
166: * in first mbuf.
167: */
168: s = splimp();
169: IF_DEQUEUE(&ipintrq, m);
170: splx(s);
1.13 mycroft 171: if (m == 0)
1.1 cgd 172: return;
173: #ifdef DIAGNOSTIC
174: if ((m->m_flags & M_PKTHDR) == 0)
175: panic("ipintr no HDR");
176: #endif
177: /*
178: * If no IP addresses have been set yet but the interfaces
179: * are receiving, can't do anything with incoming packets yet.
180: */
1.22 mycroft 181: if (in_ifaddr.tqh_first == 0)
1.1 cgd 182: goto bad;
183: ipstat.ips_total++;
184: if (m->m_len < sizeof (struct ip) &&
185: (m = m_pullup(m, sizeof (struct ip))) == 0) {
186: ipstat.ips_toosmall++;
187: goto next;
188: }
189: ip = mtod(m, struct ip *);
1.13 mycroft 190: if (ip->ip_v != IPVERSION) {
191: ipstat.ips_badvers++;
192: goto bad;
193: }
1.1 cgd 194: hlen = ip->ip_hl << 2;
195: if (hlen < sizeof(struct ip)) { /* minimum header length */
196: ipstat.ips_badhlen++;
197: goto bad;
198: }
199: if (hlen > m->m_len) {
200: if ((m = m_pullup(m, hlen)) == 0) {
201: ipstat.ips_badhlen++;
202: goto next;
203: }
204: ip = mtod(m, struct ip *);
205: }
1.28 christos 206: if ((ip->ip_sum = in_cksum(m, hlen)) != 0) {
1.1 cgd 207: ipstat.ips_badsum++;
208: goto bad;
209: }
210:
211: /*
212: * Convert fields to host representation.
213: */
214: NTOHS(ip->ip_len);
215: if (ip->ip_len < hlen) {
216: ipstat.ips_badlen++;
217: goto bad;
218: }
219: NTOHS(ip->ip_id);
220: NTOHS(ip->ip_off);
221:
222: /*
223: * Check that the amount of data in the buffers
224: * is as at least much as the IP header would have us expect.
225: * Trim mbufs if longer than we expect.
226: * Drop packet if shorter than we expect.
227: */
228: if (m->m_pkthdr.len < ip->ip_len) {
229: ipstat.ips_tooshort++;
230: goto bad;
231: }
232: if (m->m_pkthdr.len > ip->ip_len) {
233: if (m->m_len == m->m_pkthdr.len) {
234: m->m_len = ip->ip_len;
235: m->m_pkthdr.len = ip->ip_len;
236: } else
237: m_adj(m, ip->ip_len - m->m_pkthdr.len);
238: }
239:
240: /*
241: * Process options and, if not destined for us,
242: * ship it on. ip_dooptions returns 1 when an
243: * error was detected (causing an icmp message
244: * to be sent and the original packet to be freed).
245: */
246: ip_nhops = 0; /* for source routed packets */
247: if (hlen > sizeof (struct ip) && ip_dooptions(m))
248: goto next;
249:
250: /*
251: * Check our list of addresses, to see if the packet is for us.
252: */
1.22 mycroft 253: for (ia = in_ifaddr.tqh_first; ia; ia = ia->ia_list.tqe_next) {
1.20 mycroft 254: if (ip->ip_dst.s_addr == ia->ia_addr.sin_addr.s_addr)
1.1 cgd 255: goto ours;
1.27 thorpej 256: if (((ip_directedbcast == 0) || (ip_directedbcast &&
257: ia->ia_ifp == m->m_pkthdr.rcvif)) &&
1.1 cgd 258: (ia->ia_ifp->if_flags & IFF_BROADCAST)) {
1.20 mycroft 259: if (ip->ip_dst.s_addr == ia->ia_broadaddr.sin_addr.s_addr ||
260: ip->ip_dst.s_addr == ia->ia_netbroadcast.s_addr ||
261: /*
262: * Look for all-0's host part (old broadcast addr),
263: * either for subnet or net.
264: */
265: ip->ip_dst.s_addr == ia->ia_subnet ||
1.18 mycroft 266: ip->ip_dst.s_addr == ia->ia_net)
1.1 cgd 267: goto ours;
268: }
269: }
1.18 mycroft 270: if (IN_MULTICAST(ip->ip_dst.s_addr)) {
1.4 hpeyerl 271: struct in_multi *inm;
272: #ifdef MROUTING
273: extern struct socket *ip_mrouter;
1.10 brezak 274:
275: if (m->m_flags & M_EXT) {
276: if ((m = m_pullup(m, hlen)) == 0) {
277: ipstat.ips_toosmall++;
278: goto next;
279: }
280: ip = mtod(m, struct ip *);
281: }
1.4 hpeyerl 282:
283: if (ip_mrouter) {
284: /*
285: * If we are acting as a multicast router, all
286: * incoming multicast packets are passed to the
287: * kernel-level multicast forwarding function.
288: * The packet is returned (relatively) intact; if
289: * ip_mforward() returns a non-zero value, the packet
290: * must be discarded, else it may be accepted below.
291: *
292: * (The IP ident field is put in the same byte order
293: * as expected when ip_mforward() is called from
294: * ip_output().)
295: */
296: ip->ip_id = htons(ip->ip_id);
1.13 mycroft 297: if (ip_mforward(m, m->m_pkthdr.rcvif) != 0) {
298: ipstat.ips_cantforward++;
1.4 hpeyerl 299: m_freem(m);
300: goto next;
301: }
302: ip->ip_id = ntohs(ip->ip_id);
303:
304: /*
305: * The process-level routing demon needs to receive
306: * all multicast IGMP packets, whether or not this
307: * host belongs to their destination groups.
308: */
309: if (ip->ip_p == IPPROTO_IGMP)
310: goto ours;
1.13 mycroft 311: ipstat.ips_forward++;
1.4 hpeyerl 312: }
313: #endif
314: /*
315: * See if we belong to the destination multicast group on the
316: * arrival interface.
317: */
318: IN_LOOKUP_MULTI(ip->ip_dst, m->m_pkthdr.rcvif, inm);
319: if (inm == NULL) {
1.13 mycroft 320: ipstat.ips_cantforward++;
1.4 hpeyerl 321: m_freem(m);
322: goto next;
323: }
324: goto ours;
325: }
1.19 mycroft 326: if (ip->ip_dst.s_addr == INADDR_BROADCAST ||
327: ip->ip_dst.s_addr == INADDR_ANY)
1.1 cgd 328: goto ours;
329:
330: /*
331: * Not for us; forward if possible and desirable.
332: */
333: if (ipforwarding == 0) {
334: ipstat.ips_cantforward++;
335: m_freem(m);
336: } else
337: ip_forward(m, 0);
338: goto next;
339:
340: ours:
341: /*
342: * If offset or IP_MF are set, must reassemble.
343: * Otherwise, nothing need be done.
344: * (We could look in the reassembly queue to see
345: * if the packet was previously fragmented,
346: * but it's not worth the time; just let them time out.)
347: */
348: if (ip->ip_off &~ IP_DF) {
349: if (m->m_flags & M_EXT) { /* XXX */
350: if ((m = m_pullup(m, sizeof (struct ip))) == 0) {
351: ipstat.ips_toosmall++;
352: goto next;
353: }
354: ip = mtod(m, struct ip *);
355: }
356: /*
357: * Look for queue of fragments
358: * of this datagram.
359: */
1.25 cgd 360: for (fp = ipq.lh_first; fp != NULL; fp = fp->ipq_q.le_next)
1.1 cgd 361: if (ip->ip_id == fp->ipq_id &&
362: ip->ip_src.s_addr == fp->ipq_src.s_addr &&
363: ip->ip_dst.s_addr == fp->ipq_dst.s_addr &&
364: ip->ip_p == fp->ipq_p)
365: goto found;
366: fp = 0;
367: found:
368:
369: /*
370: * Adjust ip_len to not reflect header,
1.25 cgd 371: * set ipqe_mff if more fragments are expected,
1.1 cgd 372: * convert offset of this to bytes.
373: */
374: ip->ip_len -= hlen;
1.25 cgd 375: mff = (ip->ip_off & IP_MF) != 0;
376: if (mff) {
1.16 cgd 377: /*
378: * Make sure that fragments have a data length
379: * that's a non-zero multiple of 8 bytes.
380: */
1.17 cgd 381: if (ip->ip_len == 0 || (ip->ip_len & 0x7) != 0) {
1.16 cgd 382: ipstat.ips_badfrags++;
383: goto bad;
384: }
385: }
1.1 cgd 386: ip->ip_off <<= 3;
387:
388: /*
389: * If datagram marked as having more fragments
390: * or if this is not the first fragment,
391: * attempt reassembly; if it succeeds, proceed.
392: */
1.25 cgd 393: if (mff || ip->ip_off) {
1.1 cgd 394: ipstat.ips_fragments++;
1.25 cgd 395: MALLOC(ipqe, struct ipqent *, sizeof (struct ipqent),
396: M_IPQ, M_NOWAIT);
397: if (ipqe == NULL) {
398: ipstat.ips_rcvmemdrop++;
399: goto bad;
400: }
401: ipqe->ipqe_mff = mff;
402: ipqe->ipqe_ip = ip;
403: ip = ip_reass(ipqe, fp);
1.1 cgd 404: if (ip == 0)
405: goto next;
1.13 mycroft 406: ipstat.ips_reassembled++;
1.1 cgd 407: m = dtom(ip);
408: } else
409: if (fp)
410: ip_freef(fp);
411: } else
412: ip->ip_len -= hlen;
413:
414: /*
415: * Switch out to protocol's input routine.
416: */
417: ipstat.ips_delivered++;
418: (*inetsw[ip_protox[ip->ip_p]].pr_input)(m, hlen);
419: goto next;
420: bad:
421: m_freem(m);
422: goto next;
423: }
424:
425: /*
426: * Take incoming datagram fragment and try to
427: * reassemble it into whole datagram. If a chain for
428: * reassembly of this datagram already exists, then it
429: * is given as fp; otherwise have to make a chain.
430: */
431: struct ip *
1.25 cgd 432: ip_reass(ipqe, fp)
433: register struct ipqent *ipqe;
1.1 cgd 434: register struct ipq *fp;
435: {
1.25 cgd 436: register struct mbuf *m = dtom(ipqe->ipqe_ip);
437: register struct ipqent *nq, *p, *q;
438: struct ip *ip;
1.1 cgd 439: struct mbuf *t;
1.25 cgd 440: int hlen = ipqe->ipqe_ip->ip_hl << 2;
1.1 cgd 441: int i, next;
442:
443: /*
444: * Presence of header sizes in mbufs
445: * would confuse code below.
446: */
447: m->m_data += hlen;
448: m->m_len -= hlen;
449:
450: /*
451: * If first fragment to arrive, create a reassembly queue.
452: */
453: if (fp == 0) {
454: if ((t = m_get(M_DONTWAIT, MT_FTABLE)) == NULL)
455: goto dropfrag;
456: fp = mtod(t, struct ipq *);
1.25 cgd 457: LIST_INSERT_HEAD(&ipq, fp, ipq_q);
1.1 cgd 458: fp->ipq_ttl = IPFRAGTTL;
1.25 cgd 459: fp->ipq_p = ipqe->ipqe_ip->ip_p;
460: fp->ipq_id = ipqe->ipqe_ip->ip_id;
461: LIST_INIT(&fp->ipq_fragq);
462: fp->ipq_src = ipqe->ipqe_ip->ip_src;
463: fp->ipq_dst = ipqe->ipqe_ip->ip_dst;
464: p = NULL;
1.1 cgd 465: goto insert;
466: }
467:
468: /*
469: * Find a segment which begins after this one does.
470: */
1.25 cgd 471: for (p = NULL, q = fp->ipq_fragq.lh_first; q != NULL;
472: p = q, q = q->ipqe_q.le_next)
473: if (q->ipqe_ip->ip_off > ipqe->ipqe_ip->ip_off)
1.1 cgd 474: break;
475:
476: /*
477: * If there is a preceding segment, it may provide some of
478: * our data already. If so, drop the data from the incoming
479: * segment. If it provides all of our data, drop us.
480: */
1.25 cgd 481: if (p != NULL) {
482: i = p->ipqe_ip->ip_off + p->ipqe_ip->ip_len -
483: ipqe->ipqe_ip->ip_off;
1.1 cgd 484: if (i > 0) {
1.25 cgd 485: if (i >= ipqe->ipqe_ip->ip_len)
1.1 cgd 486: goto dropfrag;
1.25 cgd 487: m_adj(dtom(ipqe->ipqe_ip), i);
488: ipqe->ipqe_ip->ip_off += i;
489: ipqe->ipqe_ip->ip_len -= i;
1.1 cgd 490: }
491: }
492:
493: /*
494: * While we overlap succeeding segments trim them or,
495: * if they are completely covered, dequeue them.
496: */
1.25 cgd 497: for (; q != NULL && ipqe->ipqe_ip->ip_off + ipqe->ipqe_ip->ip_len >
498: q->ipqe_ip->ip_off; q = nq) {
499: i = (ipqe->ipqe_ip->ip_off + ipqe->ipqe_ip->ip_len) -
500: q->ipqe_ip->ip_off;
501: if (i < q->ipqe_ip->ip_len) {
502: q->ipqe_ip->ip_len -= i;
503: q->ipqe_ip->ip_off += i;
504: m_adj(dtom(q->ipqe_ip), i);
1.1 cgd 505: break;
506: }
1.25 cgd 507: nq = q->ipqe_q.le_next;
508: m_freem(dtom(q->ipqe_ip));
509: LIST_REMOVE(q, ipqe_q);
510: FREE(q, M_IPQ);
1.1 cgd 511: }
512:
513: insert:
514: /*
515: * Stick new segment in its place;
516: * check for complete reassembly.
517: */
1.25 cgd 518: if (p == NULL) {
519: LIST_INSERT_HEAD(&fp->ipq_fragq, ipqe, ipqe_q);
520: } else {
521: LIST_INSERT_AFTER(p, ipqe, ipqe_q);
522: }
1.1 cgd 523: next = 0;
1.25 cgd 524: for (p = NULL, q = fp->ipq_fragq.lh_first; q != NULL;
525: p = q, q = q->ipqe_q.le_next) {
526: if (q->ipqe_ip->ip_off != next)
1.1 cgd 527: return (0);
1.25 cgd 528: next += q->ipqe_ip->ip_len;
1.1 cgd 529: }
1.25 cgd 530: if (p->ipqe_mff)
1.1 cgd 531: return (0);
532:
533: /*
1.30.4.1! thorpej 534: * Reassembly is complete. Check for a bogus message size and
! 535: * concatenate fragments.
1.1 cgd 536: */
1.25 cgd 537: q = fp->ipq_fragq.lh_first;
538: ip = q->ipqe_ip;
1.30.4.1! thorpej 539: if ((next + (ip->ip_hl << 2)) > IP_MAXPACKET) {
! 540: ipstat.ips_toolong++;
! 541: ip_freef(fp);
! 542: return (0);
! 543: }
1.25 cgd 544: m = dtom(q->ipqe_ip);
1.1 cgd 545: t = m->m_next;
546: m->m_next = 0;
547: m_cat(m, t);
1.25 cgd 548: nq = q->ipqe_q.le_next;
549: FREE(q, M_IPQ);
550: for (q = nq; q != NULL; q = nq) {
551: t = dtom(q->ipqe_ip);
552: nq = q->ipqe_q.le_next;
553: FREE(q, M_IPQ);
1.1 cgd 554: m_cat(m, t);
555: }
556:
557: /*
558: * Create header for new ip packet by
559: * modifying header of first packet;
560: * dequeue and discard fragment reassembly header.
561: * Make header visible.
562: */
563: ip->ip_len = next;
1.25 cgd 564: ip->ip_src = fp->ipq_src;
565: ip->ip_dst = fp->ipq_dst;
566: LIST_REMOVE(fp, ipq_q);
1.1 cgd 567: (void) m_free(dtom(fp));
568: m->m_len += (ip->ip_hl << 2);
569: m->m_data -= (ip->ip_hl << 2);
570: /* some debugging cruft by sklower, below, will go away soon */
571: if (m->m_flags & M_PKTHDR) { /* XXX this should be done elsewhere */
572: register int plen = 0;
573: for (t = m; m; m = m->m_next)
574: plen += m->m_len;
575: t->m_pkthdr.len = plen;
576: }
1.25 cgd 577: return (ip);
1.1 cgd 578:
579: dropfrag:
580: ipstat.ips_fragdropped++;
581: m_freem(m);
1.25 cgd 582: FREE(ipqe, M_IPQ);
1.1 cgd 583: return (0);
584: }
585:
586: /*
587: * Free a fragment reassembly header and all
588: * associated datagrams.
589: */
1.8 mycroft 590: void
1.1 cgd 591: ip_freef(fp)
592: struct ipq *fp;
593: {
1.25 cgd 594: register struct ipqent *q, *p;
1.1 cgd 595:
1.25 cgd 596: for (q = fp->ipq_fragq.lh_first; q != NULL; q = p) {
597: p = q->ipqe_q.le_next;
598: m_freem(dtom(q->ipqe_ip));
599: LIST_REMOVE(q, ipqe_q);
600: FREE(q, M_IPQ);
1.1 cgd 601: }
1.25 cgd 602: LIST_REMOVE(fp, ipq_q);
1.1 cgd 603: (void) m_free(dtom(fp));
604: }
605:
606: /*
607: * IP timer processing;
608: * if a timer expires on a reassembly
609: * queue, discard it.
610: */
1.8 mycroft 611: void
1.1 cgd 612: ip_slowtimo()
613: {
1.25 cgd 614: register struct ipq *fp, *nfp;
1.24 mycroft 615: int s = splsoftnet();
1.1 cgd 616:
1.25 cgd 617: for (fp = ipq.lh_first; fp != NULL; fp = nfp) {
618: nfp = fp->ipq_q.le_next;
619: if (--fp->ipq_ttl == 0) {
1.1 cgd 620: ipstat.ips_fragtimeout++;
1.25 cgd 621: ip_freef(fp);
1.1 cgd 622: }
623: }
624: splx(s);
625: }
626:
627: /*
628: * Drain off all datagram fragments.
629: */
1.8 mycroft 630: void
1.1 cgd 631: ip_drain()
632: {
633:
1.25 cgd 634: while (ipq.lh_first != NULL) {
1.1 cgd 635: ipstat.ips_fragdropped++;
1.25 cgd 636: ip_freef(ipq.lh_first);
1.1 cgd 637: }
638: }
639:
640: /*
641: * Do option processing on a datagram,
642: * possibly discarding it if bad options are encountered,
643: * or forwarding it if source-routed.
644: * Returns 1 if packet has been forwarded/freed,
645: * 0 if the packet should be processed further.
646: */
1.8 mycroft 647: int
1.1 cgd 648: ip_dooptions(m)
649: struct mbuf *m;
650: {
651: register struct ip *ip = mtod(m, struct ip *);
652: register u_char *cp;
653: register struct ip_timestamp *ipt;
654: register struct in_ifaddr *ia;
655: int opt, optlen, cnt, off, code, type = ICMP_PARAMPROB, forward = 0;
1.13 mycroft 656: struct in_addr *sin, dst;
1.1 cgd 657: n_time ntime;
658:
1.13 mycroft 659: dst = ip->ip_dst;
1.1 cgd 660: cp = (u_char *)(ip + 1);
661: cnt = (ip->ip_hl << 2) - sizeof (struct ip);
662: for (; cnt > 0; cnt -= optlen, cp += optlen) {
663: opt = cp[IPOPT_OPTVAL];
664: if (opt == IPOPT_EOL)
665: break;
666: if (opt == IPOPT_NOP)
667: optlen = 1;
668: else {
669: optlen = cp[IPOPT_OLEN];
670: if (optlen <= 0 || optlen > cnt) {
671: code = &cp[IPOPT_OLEN] - (u_char *)ip;
672: goto bad;
673: }
674: }
675: switch (opt) {
676:
677: default:
678: break;
679:
680: /*
681: * Source routing with record.
682: * Find interface with current destination address.
683: * If none on this machine then drop if strictly routed,
684: * or do nothing if loosely routed.
685: * Record interface address and bring up next address
686: * component. If strictly routed make sure next
687: * address is on directly accessible net.
688: */
689: case IPOPT_LSRR:
690: case IPOPT_SSRR:
691: if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) {
692: code = &cp[IPOPT_OFFSET] - (u_char *)ip;
693: goto bad;
694: }
695: ipaddr.sin_addr = ip->ip_dst;
1.19 mycroft 696: ia = ifatoia(ifa_ifwithaddr(sintosa(&ipaddr)));
1.1 cgd 697: if (ia == 0) {
698: if (opt == IPOPT_SSRR) {
699: type = ICMP_UNREACH;
700: code = ICMP_UNREACH_SRCFAIL;
701: goto bad;
702: }
703: /*
704: * Loose routing, and not at next destination
705: * yet; nothing to do except forward.
706: */
707: break;
708: }
709: off--; /* 0 origin */
710: if (off > optlen - sizeof(struct in_addr)) {
711: /*
712: * End of source route. Should be for us.
713: */
714: save_rte(cp, ip->ip_src);
715: break;
716: }
717: /*
718: * locate outgoing interface
719: */
720: bcopy((caddr_t)(cp + off), (caddr_t)&ipaddr.sin_addr,
721: sizeof(ipaddr.sin_addr));
722: if (opt == IPOPT_SSRR) {
723: #define INA struct in_ifaddr *
724: #define SA struct sockaddr *
1.29 mrg 725: ia = (INA)ifa_ifwithladdr((SA)&ipaddr);
1.1 cgd 726: } else
727: ia = ip_rtaddr(ipaddr.sin_addr);
728: if (ia == 0) {
729: type = ICMP_UNREACH;
730: code = ICMP_UNREACH_SRCFAIL;
731: goto bad;
732: }
733: ip->ip_dst = ipaddr.sin_addr;
1.20 mycroft 734: bcopy((caddr_t)&ia->ia_addr.sin_addr,
1.1 cgd 735: (caddr_t)(cp + off), sizeof(struct in_addr));
736: cp[IPOPT_OFFSET] += sizeof(struct in_addr);
1.13 mycroft 737: /*
738: * Let ip_intr's mcast routing check handle mcast pkts
739: */
1.18 mycroft 740: forward = !IN_MULTICAST(ip->ip_dst.s_addr);
1.1 cgd 741: break;
742:
743: case IPOPT_RR:
744: if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) {
745: code = &cp[IPOPT_OFFSET] - (u_char *)ip;
746: goto bad;
747: }
748: /*
749: * If no space remains, ignore.
750: */
751: off--; /* 0 origin */
752: if (off > optlen - sizeof(struct in_addr))
753: break;
754: bcopy((caddr_t)(&ip->ip_dst), (caddr_t)&ipaddr.sin_addr,
755: sizeof(ipaddr.sin_addr));
756: /*
757: * locate outgoing interface; if we're the destination,
758: * use the incoming interface (should be same).
759: */
760: if ((ia = (INA)ifa_ifwithaddr((SA)&ipaddr)) == 0 &&
761: (ia = ip_rtaddr(ipaddr.sin_addr)) == 0) {
762: type = ICMP_UNREACH;
763: code = ICMP_UNREACH_HOST;
764: goto bad;
765: }
1.20 mycroft 766: bcopy((caddr_t)&ia->ia_addr.sin_addr,
1.1 cgd 767: (caddr_t)(cp + off), sizeof(struct in_addr));
768: cp[IPOPT_OFFSET] += sizeof(struct in_addr);
769: break;
770:
771: case IPOPT_TS:
772: code = cp - (u_char *)ip;
773: ipt = (struct ip_timestamp *)cp;
774: if (ipt->ipt_len < 5)
775: goto bad;
1.15 cgd 776: if (ipt->ipt_ptr > ipt->ipt_len - sizeof (int32_t)) {
1.1 cgd 777: if (++ipt->ipt_oflw == 0)
778: goto bad;
779: break;
780: }
781: sin = (struct in_addr *)(cp + ipt->ipt_ptr - 1);
782: switch (ipt->ipt_flg) {
783:
784: case IPOPT_TS_TSONLY:
785: break;
786:
787: case IPOPT_TS_TSANDADDR:
788: if (ipt->ipt_ptr + sizeof(n_time) +
789: sizeof(struct in_addr) > ipt->ipt_len)
790: goto bad;
1.13 mycroft 791: ipaddr.sin_addr = dst;
792: ia = (INA)ifaof_ifpforaddr((SA)&ipaddr,
793: m->m_pkthdr.rcvif);
794: if (ia == 0)
795: continue;
1.20 mycroft 796: bcopy((caddr_t)&ia->ia_addr.sin_addr,
1.1 cgd 797: (caddr_t)sin, sizeof(struct in_addr));
798: ipt->ipt_ptr += sizeof(struct in_addr);
799: break;
800:
801: case IPOPT_TS_PRESPEC:
802: if (ipt->ipt_ptr + sizeof(n_time) +
803: sizeof(struct in_addr) > ipt->ipt_len)
804: goto bad;
805: bcopy((caddr_t)sin, (caddr_t)&ipaddr.sin_addr,
806: sizeof(struct in_addr));
807: if (ifa_ifwithaddr((SA)&ipaddr) == 0)
808: continue;
809: ipt->ipt_ptr += sizeof(struct in_addr);
810: break;
811:
812: default:
813: goto bad;
814: }
815: ntime = iptime();
816: bcopy((caddr_t)&ntime, (caddr_t)cp + ipt->ipt_ptr - 1,
817: sizeof(n_time));
818: ipt->ipt_ptr += sizeof(n_time);
819: }
820: }
821: if (forward) {
1.26 thorpej 822: if (ip_forwsrcrt == 0) {
823: type = ICMP_UNREACH;
824: code = ICMP_UNREACH_SRCFAIL;
825: goto bad;
826: }
1.1 cgd 827: ip_forward(m, 1);
828: return (1);
1.13 mycroft 829: }
830: return (0);
1.1 cgd 831: bad:
1.13 mycroft 832: ip->ip_len -= ip->ip_hl << 2; /* XXX icmp_error adds in hdr length */
833: icmp_error(m, type, code, 0, 0);
834: ipstat.ips_badoptions++;
1.1 cgd 835: return (1);
836: }
837:
838: /*
839: * Given address of next destination (final or next hop),
840: * return internet address info of interface to be used to get there.
841: */
842: struct in_ifaddr *
843: ip_rtaddr(dst)
844: struct in_addr dst;
845: {
846: register struct sockaddr_in *sin;
847:
1.19 mycroft 848: sin = satosin(&ipforward_rt.ro_dst);
1.1 cgd 849:
850: if (ipforward_rt.ro_rt == 0 || dst.s_addr != sin->sin_addr.s_addr) {
851: if (ipforward_rt.ro_rt) {
852: RTFREE(ipforward_rt.ro_rt);
853: ipforward_rt.ro_rt = 0;
854: }
855: sin->sin_family = AF_INET;
856: sin->sin_len = sizeof(*sin);
857: sin->sin_addr = dst;
858:
859: rtalloc(&ipforward_rt);
860: }
861: if (ipforward_rt.ro_rt == 0)
862: return ((struct in_ifaddr *)0);
1.19 mycroft 863: return (ifatoia(ipforward_rt.ro_rt->rt_ifa));
1.1 cgd 864: }
865:
866: /*
867: * Save incoming source route for use in replies,
868: * to be picked up later by ip_srcroute if the receiver is interested.
869: */
1.13 mycroft 870: void
1.1 cgd 871: save_rte(option, dst)
872: u_char *option;
873: struct in_addr dst;
874: {
875: unsigned olen;
876:
877: olen = option[IPOPT_OLEN];
878: #ifdef DIAGNOSTIC
879: if (ipprintfs)
880: printf("save_rte: olen %d\n", olen);
881: #endif
882: if (olen > sizeof(ip_srcrt) - (1 + sizeof(dst)))
883: return;
884: bcopy((caddr_t)option, (caddr_t)ip_srcrt.srcopt, olen);
885: ip_nhops = (olen - IPOPT_OFFSET - 1) / sizeof(struct in_addr);
886: ip_srcrt.dst = dst;
887: }
888:
889: /*
890: * Retrieve incoming source route for use in replies,
891: * in the same form used by setsockopt.
892: * The first hop is placed before the options, will be removed later.
893: */
894: struct mbuf *
895: ip_srcroute()
896: {
897: register struct in_addr *p, *q;
898: register struct mbuf *m;
899:
900: if (ip_nhops == 0)
901: return ((struct mbuf *)0);
902: m = m_get(M_DONTWAIT, MT_SOOPTS);
903: if (m == 0)
904: return ((struct mbuf *)0);
905:
1.13 mycroft 906: #define OPTSIZ (sizeof(ip_srcrt.nop) + sizeof(ip_srcrt.srcopt))
1.1 cgd 907:
908: /* length is (nhops+1)*sizeof(addr) + sizeof(nop + srcrt header) */
909: m->m_len = ip_nhops * sizeof(struct in_addr) + sizeof(struct in_addr) +
910: OPTSIZ;
911: #ifdef DIAGNOSTIC
912: if (ipprintfs)
913: printf("ip_srcroute: nhops %d mlen %d", ip_nhops, m->m_len);
914: #endif
915:
916: /*
917: * First save first hop for return route
918: */
919: p = &ip_srcrt.route[ip_nhops - 1];
920: *(mtod(m, struct in_addr *)) = *p--;
921: #ifdef DIAGNOSTIC
922: if (ipprintfs)
1.30 christos 923: printf(" hops %x", ntohl(mtod(m, struct in_addr *)->s_addr));
1.1 cgd 924: #endif
925:
926: /*
927: * Copy option fields and padding (nop) to mbuf.
928: */
929: ip_srcrt.nop = IPOPT_NOP;
930: ip_srcrt.srcopt[IPOPT_OFFSET] = IPOPT_MINOFF;
931: bcopy((caddr_t)&ip_srcrt.nop,
932: mtod(m, caddr_t) + sizeof(struct in_addr), OPTSIZ);
933: q = (struct in_addr *)(mtod(m, caddr_t) +
934: sizeof(struct in_addr) + OPTSIZ);
935: #undef OPTSIZ
936: /*
937: * Record return path as an IP source route,
938: * reversing the path (pointers are now aligned).
939: */
940: while (p >= ip_srcrt.route) {
941: #ifdef DIAGNOSTIC
942: if (ipprintfs)
1.30 christos 943: printf(" %x", ntohl(q->s_addr));
1.1 cgd 944: #endif
945: *q++ = *p--;
946: }
947: /*
948: * Last hop goes to final destination.
949: */
950: *q = ip_srcrt.dst;
951: #ifdef DIAGNOSTIC
952: if (ipprintfs)
1.30 christos 953: printf(" %x\n", ntohl(q->s_addr));
1.1 cgd 954: #endif
955: return (m);
956: }
957:
958: /*
959: * Strip out IP options, at higher
960: * level protocol in the kernel.
961: * Second argument is buffer to which options
962: * will be moved, and return value is their length.
963: * XXX should be deleted; last arg currently ignored.
964: */
1.8 mycroft 965: void
1.1 cgd 966: ip_stripoptions(m, mopt)
967: register struct mbuf *m;
968: struct mbuf *mopt;
969: {
970: register int i;
971: struct ip *ip = mtod(m, struct ip *);
972: register caddr_t opts;
973: int olen;
974:
975: olen = (ip->ip_hl<<2) - sizeof (struct ip);
976: opts = (caddr_t)(ip + 1);
977: i = m->m_len - (sizeof (struct ip) + olen);
978: bcopy(opts + olen, opts, (unsigned)i);
979: m->m_len -= olen;
980: if (m->m_flags & M_PKTHDR)
981: m->m_pkthdr.len -= olen;
982: ip->ip_hl = sizeof(struct ip) >> 2;
983: }
984:
1.23 mycroft 985: int inetctlerrmap[PRC_NCMDS] = {
1.1 cgd 986: 0, 0, 0, 0,
987: 0, EMSGSIZE, EHOSTDOWN, EHOSTUNREACH,
988: EHOSTUNREACH, EHOSTUNREACH, ECONNREFUSED, ECONNREFUSED,
989: EMSGSIZE, EHOSTUNREACH, 0, 0,
990: 0, 0, 0, 0,
991: ENOPROTOOPT
992: };
993:
994: /*
995: * Forward a packet. If some error occurs return the sender
996: * an icmp packet. Note we can't always generate a meaningful
997: * icmp message because icmp doesn't have a large enough repertoire
998: * of codes and types.
999: *
1000: * If not forwarding, just drop the packet. This could be confusing
1001: * if ipforwarding was zero but some routing protocol was advancing
1002: * us as a gateway to somewhere. However, we must let the routing
1003: * protocol deal with that.
1004: *
1005: * The srcrt parameter indicates whether the packet is being forwarded
1006: * via a source route.
1007: */
1.13 mycroft 1008: void
1.1 cgd 1009: ip_forward(m, srcrt)
1010: struct mbuf *m;
1011: int srcrt;
1012: {
1013: register struct ip *ip = mtod(m, struct ip *);
1014: register struct sockaddr_in *sin;
1015: register struct rtentry *rt;
1.28 christos 1016: int error, type = 0, code = 0;
1.1 cgd 1017: struct mbuf *mcopy;
1.13 mycroft 1018: n_long dest;
1019: struct ifnet *destifp;
1.1 cgd 1020:
1.13 mycroft 1021: dest = 0;
1.1 cgd 1022: #ifdef DIAGNOSTIC
1023: if (ipprintfs)
1.28 christos 1024: printf("forward: src %x dst %x ttl %x\n",
1025: ip->ip_src.s_addr, ip->ip_dst.s_addr, ip->ip_ttl);
1.1 cgd 1026: #endif
1027: if (m->m_flags & M_BCAST || in_canforward(ip->ip_dst) == 0) {
1028: ipstat.ips_cantforward++;
1029: m_freem(m);
1030: return;
1031: }
1032: HTONS(ip->ip_id);
1033: if (ip->ip_ttl <= IPTTLDEC) {
1.13 mycroft 1034: icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, dest, 0);
1.1 cgd 1035: return;
1036: }
1037: ip->ip_ttl -= IPTTLDEC;
1038:
1.19 mycroft 1039: sin = satosin(&ipforward_rt.ro_dst);
1.1 cgd 1040: if ((rt = ipforward_rt.ro_rt) == 0 ||
1041: ip->ip_dst.s_addr != sin->sin_addr.s_addr) {
1042: if (ipforward_rt.ro_rt) {
1043: RTFREE(ipforward_rt.ro_rt);
1044: ipforward_rt.ro_rt = 0;
1045: }
1046: sin->sin_family = AF_INET;
1047: sin->sin_len = sizeof(*sin);
1048: sin->sin_addr = ip->ip_dst;
1049:
1050: rtalloc(&ipforward_rt);
1051: if (ipforward_rt.ro_rt == 0) {
1.13 mycroft 1052: icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, dest, 0);
1.1 cgd 1053: return;
1054: }
1055: rt = ipforward_rt.ro_rt;
1056: }
1057:
1058: /*
1059: * Save at most 64 bytes of the packet in case
1060: * we need to generate an ICMP message to the src.
1061: */
1062: mcopy = m_copy(m, 0, imin((int)ip->ip_len, 64));
1063:
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: if (rt->rt_ifp == m->m_pkthdr.rcvif &&
1073: (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0 &&
1074: satosin(rt_key(rt))->sin_addr.s_addr != 0 &&
1075: ipsendredirects && !srcrt) {
1.19 mycroft 1076: if (rt->rt_ifa &&
1077: (ip->ip_src.s_addr & ifatoia(rt->rt_ifa)->ia_subnetmask) ==
1078: ifatoia(rt->rt_ifa)->ia_subnet) {
1.1 cgd 1079: if (rt->rt_flags & RTF_GATEWAY)
1.13 mycroft 1080: dest = satosin(rt->rt_gateway)->sin_addr.s_addr;
1.1 cgd 1081: else
1.13 mycroft 1082: dest = ip->ip_dst.s_addr;
1083: /* Router requirements says to only send host redirects */
1.1 cgd 1084: type = ICMP_REDIRECT;
1.13 mycroft 1085: code = ICMP_REDIRECT_HOST;
1.1 cgd 1086: #ifdef DIAGNOSTIC
1087: if (ipprintfs)
1.30 christos 1088: printf("redirect (%d) to %x\n", code, (u_int32_t)dest);
1.1 cgd 1089: #endif
1090: }
1091: }
1092:
1.27 thorpej 1093: error = ip_output(m, (struct mbuf *)0, &ipforward_rt,
1094: (IP_FORWARDING | (ip_directedbcast ? IP_ALLOWBROADCAST : 0)), 0);
1.1 cgd 1095: if (error)
1096: ipstat.ips_cantforward++;
1097: else {
1098: ipstat.ips_forward++;
1099: if (type)
1100: ipstat.ips_redirectsent++;
1101: else {
1102: if (mcopy)
1103: m_freem(mcopy);
1104: return;
1105: }
1106: }
1107: if (mcopy == NULL)
1108: return;
1.13 mycroft 1109: destifp = NULL;
1110:
1.1 cgd 1111: switch (error) {
1112:
1113: case 0: /* forwarded, but need redirect */
1114: /* type, code set above */
1115: break;
1116:
1117: case ENETUNREACH: /* shouldn't happen, checked above */
1118: case EHOSTUNREACH:
1119: case ENETDOWN:
1120: case EHOSTDOWN:
1121: default:
1122: type = ICMP_UNREACH;
1123: code = ICMP_UNREACH_HOST;
1124: break;
1125:
1126: case EMSGSIZE:
1127: type = ICMP_UNREACH;
1128: code = ICMP_UNREACH_NEEDFRAG;
1.13 mycroft 1129: if (ipforward_rt.ro_rt)
1130: destifp = ipforward_rt.ro_rt->rt_ifp;
1.1 cgd 1131: ipstat.ips_cantfrag++;
1132: break;
1133:
1134: case ENOBUFS:
1135: type = ICMP_SOURCEQUENCH;
1136: code = 0;
1137: break;
1138: }
1.13 mycroft 1139: icmp_error(mcopy, type, code, dest, destifp);
1140: }
1141:
1142: int
1143: ip_sysctl(name, namelen, oldp, oldlenp, newp, newlen)
1144: int *name;
1145: u_int namelen;
1146: void *oldp;
1147: size_t *oldlenp;
1148: void *newp;
1149: size_t newlen;
1150: {
1151: /* All sysctl names at this level are terminal. */
1152: if (namelen != 1)
1153: return (ENOTDIR);
1154:
1155: switch (name[0]) {
1156: case IPCTL_FORWARDING:
1157: return (sysctl_int(oldp, oldlenp, newp, newlen, &ipforwarding));
1158: case IPCTL_SENDREDIRECTS:
1159: return (sysctl_int(oldp, oldlenp, newp, newlen,
1160: &ipsendredirects));
1161: case IPCTL_DEFTTL:
1162: return (sysctl_int(oldp, oldlenp, newp, newlen, &ip_defttl));
1163: #ifdef notyet
1164: case IPCTL_DEFMTU:
1165: return (sysctl_int(oldp, oldlenp, newp, newlen, &ip_mtu));
1166: #endif
1.26 thorpej 1167: case IPCTL_FORWSRCRT:
1168: /*
1169: * Don't allow this to change in a secure environment.
1170: */
1171: if (securelevel > 0)
1172: return (EPERM);
1173: return (sysctl_int(oldp, oldlenp, newp, newlen,
1174: &ip_forwsrcrt));
1.27 thorpej 1175: case IPCTL_DIRECTEDBCAST:
1176: return (sysctl_int(oldp, oldlenp, newp, newlen,
1177: &ip_directedbcast));
1.13 mycroft 1178: default:
1179: return (EOPNOTSUPP);
1180: }
1181: /* NOTREACHED */
1.1 cgd 1182: }
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