Annotation of src/sys/netinet/ip_input.c, Revision 1.25
1.25 ! cgd 1: /* $NetBSD: ip_input.c,v 1.24 1995/08/12 23:59:36 mycroft 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>
1.1 cgd 48:
1.5 mycroft 49: #include <net/if.h>
50: #include <net/route.h>
1.1 cgd 51:
1.5 mycroft 52: #include <netinet/in.h>
53: #include <netinet/in_systm.h>
54: #include <netinet/ip.h>
55: #include <netinet/in_pcb.h>
56: #include <netinet/in_var.h>
57: #include <netinet/ip_var.h>
58: #include <netinet/ip_icmp.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;
1.13 mycroft 72: int ip_defttl = IPDEFTTL;
1.1 cgd 73: #ifdef DIAGNOSTIC
74: int ipprintfs = 0;
75: #endif
76:
77: extern struct domain inetdomain;
78: extern struct protosw inetsw[];
79: u_char ip_protox[IPPROTO_MAX];
80: int ipqmaxlen = IFQ_MAXLEN;
1.22 mycroft 81: struct in_ifaddrhead in_ifaddr;
1.13 mycroft 82: struct ifqueue ipintrq;
1.1 cgd 83:
84: /*
85: * We need to save the IP options in case a protocol wants to respond
86: * to an incoming packet over the same route if the packet got here
87: * using IP source routing. This allows connection establishment and
88: * maintenance when the remote end is on a network that is not known
89: * to us.
90: */
91: int ip_nhops = 0;
92: static struct ip_srcrt {
93: struct in_addr dst; /* final destination */
94: char nop; /* one NOP to align */
95: char srcopt[IPOPT_OFFSET + 1]; /* OPTVAL, OLEN and OFFSET */
96: struct in_addr route[MAX_IPOPTLEN/sizeof(struct in_addr)];
97: } ip_srcrt;
98:
1.13 mycroft 99: static void save_rte __P((u_char *, struct in_addr));
1.1 cgd 100: /*
101: * IP initialization: fill in IP protocol switch table.
102: * All protocols not implemented in kernel go to raw IP protocol handler.
103: */
1.8 mycroft 104: void
1.1 cgd 105: ip_init()
106: {
107: register struct protosw *pr;
108: register int i;
109:
110: pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW);
111: if (pr == 0)
112: panic("ip_init");
113: for (i = 0; i < IPPROTO_MAX; i++)
114: ip_protox[i] = pr - inetsw;
115: for (pr = inetdomain.dom_protosw;
116: pr < inetdomain.dom_protoswNPROTOSW; pr++)
117: if (pr->pr_domain->dom_family == PF_INET &&
118: pr->pr_protocol && pr->pr_protocol != IPPROTO_RAW)
119: ip_protox[pr->pr_protocol] = pr - inetsw;
1.25 ! cgd 120: LIST_INIT(&ipq);
1.1 cgd 121: ip_id = time.tv_sec & 0xffff;
122: ipintrq.ifq_maxlen = ipqmaxlen;
1.22 mycroft 123: TAILQ_INIT(&in_ifaddr);
1.1 cgd 124: }
125:
126: struct sockaddr_in ipaddr = { sizeof(ipaddr), AF_INET };
127: struct route ipforward_rt;
128:
129: /*
130: * Ip input routine. Checksum and byte swap header. If fragmented
131: * try to reassemble. Process options. Pass to next level.
132: */
1.8 mycroft 133: void
1.1 cgd 134: ipintr()
135: {
136: register struct ip *ip;
137: register struct mbuf *m;
138: register struct ipq *fp;
139: register struct in_ifaddr *ia;
1.25 ! cgd 140: struct ipqent *ipqe;
! 141: int hlen, mff, s;
1.1 cgd 142:
143: next:
144: /*
145: * Get next datagram off input queue and get IP header
146: * in first mbuf.
147: */
148: s = splimp();
149: IF_DEQUEUE(&ipintrq, m);
150: splx(s);
1.13 mycroft 151: if (m == 0)
1.1 cgd 152: return;
153: #ifdef DIAGNOSTIC
154: if ((m->m_flags & M_PKTHDR) == 0)
155: panic("ipintr no HDR");
156: #endif
157: /*
158: * If no IP addresses have been set yet but the interfaces
159: * are receiving, can't do anything with incoming packets yet.
160: */
1.22 mycroft 161: if (in_ifaddr.tqh_first == 0)
1.1 cgd 162: goto bad;
163: ipstat.ips_total++;
164: if (m->m_len < sizeof (struct ip) &&
165: (m = m_pullup(m, sizeof (struct ip))) == 0) {
166: ipstat.ips_toosmall++;
167: goto next;
168: }
169: ip = mtod(m, struct ip *);
1.13 mycroft 170: if (ip->ip_v != IPVERSION) {
171: ipstat.ips_badvers++;
172: goto bad;
173: }
1.1 cgd 174: hlen = ip->ip_hl << 2;
175: if (hlen < sizeof(struct ip)) { /* minimum header length */
176: ipstat.ips_badhlen++;
177: goto bad;
178: }
179: if (hlen > m->m_len) {
180: if ((m = m_pullup(m, hlen)) == 0) {
181: ipstat.ips_badhlen++;
182: goto next;
183: }
184: ip = mtod(m, struct ip *);
185: }
186: if (ip->ip_sum = in_cksum(m, hlen)) {
187: ipstat.ips_badsum++;
188: goto bad;
189: }
190:
191: /*
192: * Convert fields to host representation.
193: */
194: NTOHS(ip->ip_len);
195: if (ip->ip_len < hlen) {
196: ipstat.ips_badlen++;
197: goto bad;
198: }
199: NTOHS(ip->ip_id);
200: NTOHS(ip->ip_off);
201:
202: /*
203: * Check that the amount of data in the buffers
204: * is as at least much as the IP header would have us expect.
205: * Trim mbufs if longer than we expect.
206: * Drop packet if shorter than we expect.
207: */
208: if (m->m_pkthdr.len < ip->ip_len) {
209: ipstat.ips_tooshort++;
210: goto bad;
211: }
212: if (m->m_pkthdr.len > ip->ip_len) {
213: if (m->m_len == m->m_pkthdr.len) {
214: m->m_len = ip->ip_len;
215: m->m_pkthdr.len = ip->ip_len;
216: } else
217: m_adj(m, ip->ip_len - m->m_pkthdr.len);
218: }
219:
220: /*
221: * Process options and, if not destined for us,
222: * ship it on. ip_dooptions returns 1 when an
223: * error was detected (causing an icmp message
224: * to be sent and the original packet to be freed).
225: */
226: ip_nhops = 0; /* for source routed packets */
227: if (hlen > sizeof (struct ip) && ip_dooptions(m))
228: goto next;
229:
230: /*
231: * Check our list of addresses, to see if the packet is for us.
232: */
1.22 mycroft 233: for (ia = in_ifaddr.tqh_first; ia; ia = ia->ia_list.tqe_next) {
1.20 mycroft 234: if (ip->ip_dst.s_addr == ia->ia_addr.sin_addr.s_addr)
1.1 cgd 235: goto ours;
236: if (
237: #ifdef DIRECTED_BROADCAST
238: ia->ia_ifp == m->m_pkthdr.rcvif &&
239: #endif
240: (ia->ia_ifp->if_flags & IFF_BROADCAST)) {
1.20 mycroft 241: if (ip->ip_dst.s_addr == ia->ia_broadaddr.sin_addr.s_addr ||
242: ip->ip_dst.s_addr == ia->ia_netbroadcast.s_addr ||
243: /*
244: * Look for all-0's host part (old broadcast addr),
245: * either for subnet or net.
246: */
247: ip->ip_dst.s_addr == ia->ia_subnet ||
1.18 mycroft 248: ip->ip_dst.s_addr == ia->ia_net)
1.1 cgd 249: goto ours;
250: }
251: }
1.18 mycroft 252: if (IN_MULTICAST(ip->ip_dst.s_addr)) {
1.4 hpeyerl 253: struct in_multi *inm;
254: #ifdef MROUTING
255: extern struct socket *ip_mrouter;
1.10 brezak 256:
257: if (m->m_flags & M_EXT) {
258: if ((m = m_pullup(m, hlen)) == 0) {
259: ipstat.ips_toosmall++;
260: goto next;
261: }
262: ip = mtod(m, struct ip *);
263: }
1.4 hpeyerl 264:
265: if (ip_mrouter) {
266: /*
267: * If we are acting as a multicast router, all
268: * incoming multicast packets are passed to the
269: * kernel-level multicast forwarding function.
270: * The packet is returned (relatively) intact; if
271: * ip_mforward() returns a non-zero value, the packet
272: * must be discarded, else it may be accepted below.
273: *
274: * (The IP ident field is put in the same byte order
275: * as expected when ip_mforward() is called from
276: * ip_output().)
277: */
278: ip->ip_id = htons(ip->ip_id);
1.13 mycroft 279: if (ip_mforward(m, m->m_pkthdr.rcvif) != 0) {
280: ipstat.ips_cantforward++;
1.4 hpeyerl 281: m_freem(m);
282: goto next;
283: }
284: ip->ip_id = ntohs(ip->ip_id);
285:
286: /*
287: * The process-level routing demon needs to receive
288: * all multicast IGMP packets, whether or not this
289: * host belongs to their destination groups.
290: */
291: if (ip->ip_p == IPPROTO_IGMP)
292: goto ours;
1.13 mycroft 293: ipstat.ips_forward++;
1.4 hpeyerl 294: }
295: #endif
296: /*
297: * See if we belong to the destination multicast group on the
298: * arrival interface.
299: */
300: IN_LOOKUP_MULTI(ip->ip_dst, m->m_pkthdr.rcvif, inm);
301: if (inm == NULL) {
1.13 mycroft 302: ipstat.ips_cantforward++;
1.4 hpeyerl 303: m_freem(m);
304: goto next;
305: }
306: goto ours;
307: }
1.19 mycroft 308: if (ip->ip_dst.s_addr == INADDR_BROADCAST ||
309: ip->ip_dst.s_addr == INADDR_ANY)
1.1 cgd 310: goto ours;
311:
312: /*
313: * Not for us; forward if possible and desirable.
314: */
315: if (ipforwarding == 0) {
316: ipstat.ips_cantforward++;
317: m_freem(m);
318: } else
319: ip_forward(m, 0);
320: goto next;
321:
322: ours:
323: /*
324: * If offset or IP_MF are set, must reassemble.
325: * Otherwise, nothing need be done.
326: * (We could look in the reassembly queue to see
327: * if the packet was previously fragmented,
328: * but it's not worth the time; just let them time out.)
329: */
330: if (ip->ip_off &~ IP_DF) {
331: if (m->m_flags & M_EXT) { /* XXX */
332: if ((m = m_pullup(m, sizeof (struct ip))) == 0) {
333: ipstat.ips_toosmall++;
334: goto next;
335: }
336: ip = mtod(m, struct ip *);
337: }
338: /*
339: * Look for queue of fragments
340: * of this datagram.
341: */
1.25 ! cgd 342: for (fp = ipq.lh_first; fp != NULL; fp = fp->ipq_q.le_next)
1.1 cgd 343: if (ip->ip_id == fp->ipq_id &&
344: ip->ip_src.s_addr == fp->ipq_src.s_addr &&
345: ip->ip_dst.s_addr == fp->ipq_dst.s_addr &&
346: ip->ip_p == fp->ipq_p)
347: goto found;
348: fp = 0;
349: found:
350:
351: /*
352: * Adjust ip_len to not reflect header,
1.25 ! cgd 353: * set ipqe_mff if more fragments are expected,
1.1 cgd 354: * convert offset of this to bytes.
355: */
356: ip->ip_len -= hlen;
1.25 ! cgd 357: mff = (ip->ip_off & IP_MF) != 0;
! 358: if (mff) {
1.16 cgd 359: /*
360: * Make sure that fragments have a data length
361: * that's a non-zero multiple of 8 bytes.
362: */
1.17 cgd 363: if (ip->ip_len == 0 || (ip->ip_len & 0x7) != 0) {
1.16 cgd 364: ipstat.ips_badfrags++;
365: goto bad;
366: }
367: }
1.1 cgd 368: ip->ip_off <<= 3;
369:
370: /*
371: * If datagram marked as having more fragments
372: * or if this is not the first fragment,
373: * attempt reassembly; if it succeeds, proceed.
374: */
1.25 ! cgd 375: if (mff || ip->ip_off) {
1.1 cgd 376: ipstat.ips_fragments++;
1.25 ! cgd 377: MALLOC(ipqe, struct ipqent *, sizeof (struct ipqent),
! 378: M_IPQ, M_NOWAIT);
! 379: if (ipqe == NULL) {
! 380: ipstat.ips_rcvmemdrop++;
! 381: goto bad;
! 382: }
! 383: ipqe->ipqe_mff = mff;
! 384: ipqe->ipqe_ip = ip;
! 385: ip = ip_reass(ipqe, fp);
1.1 cgd 386: if (ip == 0)
387: goto next;
1.13 mycroft 388: ipstat.ips_reassembled++;
1.1 cgd 389: m = dtom(ip);
390: } else
391: if (fp)
392: ip_freef(fp);
393: } else
394: ip->ip_len -= hlen;
395:
396: /*
397: * Switch out to protocol's input routine.
398: */
399: ipstat.ips_delivered++;
400: (*inetsw[ip_protox[ip->ip_p]].pr_input)(m, hlen);
401: goto next;
402: bad:
403: m_freem(m);
404: goto next;
405: }
406:
407: /*
408: * Take incoming datagram fragment and try to
409: * reassemble it into whole datagram. If a chain for
410: * reassembly of this datagram already exists, then it
411: * is given as fp; otherwise have to make a chain.
412: */
413: struct ip *
1.25 ! cgd 414: ip_reass(ipqe, fp)
! 415: register struct ipqent *ipqe;
1.1 cgd 416: register struct ipq *fp;
417: {
1.25 ! cgd 418: register struct mbuf *m = dtom(ipqe->ipqe_ip);
! 419: register struct ipqent *nq, *p, *q;
! 420: struct ip *ip;
1.1 cgd 421: struct mbuf *t;
1.25 ! cgd 422: int hlen = ipqe->ipqe_ip->ip_hl << 2;
1.1 cgd 423: int i, next;
424:
425: /*
426: * Presence of header sizes in mbufs
427: * would confuse code below.
428: */
429: m->m_data += hlen;
430: m->m_len -= hlen;
431:
432: /*
433: * If first fragment to arrive, create a reassembly queue.
434: */
435: if (fp == 0) {
436: if ((t = m_get(M_DONTWAIT, MT_FTABLE)) == NULL)
437: goto dropfrag;
438: fp = mtod(t, struct ipq *);
1.25 ! cgd 439: LIST_INSERT_HEAD(&ipq, fp, ipq_q);
1.1 cgd 440: fp->ipq_ttl = IPFRAGTTL;
1.25 ! cgd 441: fp->ipq_p = ipqe->ipqe_ip->ip_p;
! 442: fp->ipq_id = ipqe->ipqe_ip->ip_id;
! 443: LIST_INIT(&fp->ipq_fragq);
! 444: fp->ipq_src = ipqe->ipqe_ip->ip_src;
! 445: fp->ipq_dst = ipqe->ipqe_ip->ip_dst;
! 446: p = NULL;
1.1 cgd 447: goto insert;
448: }
449:
450: /*
451: * Find a segment which begins after this one does.
452: */
1.25 ! cgd 453: for (p = NULL, q = fp->ipq_fragq.lh_first; q != NULL;
! 454: p = q, q = q->ipqe_q.le_next)
! 455: if (q->ipqe_ip->ip_off > ipqe->ipqe_ip->ip_off)
1.1 cgd 456: break;
457:
458: /*
459: * If there is a preceding segment, it may provide some of
460: * our data already. If so, drop the data from the incoming
461: * segment. If it provides all of our data, drop us.
462: */
1.25 ! cgd 463: if (p != NULL) {
! 464: i = p->ipqe_ip->ip_off + p->ipqe_ip->ip_len -
! 465: ipqe->ipqe_ip->ip_off;
1.1 cgd 466: if (i > 0) {
1.25 ! cgd 467: if (i >= ipqe->ipqe_ip->ip_len)
1.1 cgd 468: goto dropfrag;
1.25 ! cgd 469: m_adj(dtom(ipqe->ipqe_ip), i);
! 470: ipqe->ipqe_ip->ip_off += i;
! 471: ipqe->ipqe_ip->ip_len -= i;
1.1 cgd 472: }
473: }
474:
475: /*
476: * While we overlap succeeding segments trim them or,
477: * if they are completely covered, dequeue them.
478: */
1.25 ! cgd 479: for (; q != NULL && ipqe->ipqe_ip->ip_off + ipqe->ipqe_ip->ip_len >
! 480: q->ipqe_ip->ip_off; q = nq) {
! 481: i = (ipqe->ipqe_ip->ip_off + ipqe->ipqe_ip->ip_len) -
! 482: q->ipqe_ip->ip_off;
! 483: if (i < q->ipqe_ip->ip_len) {
! 484: q->ipqe_ip->ip_len -= i;
! 485: q->ipqe_ip->ip_off += i;
! 486: m_adj(dtom(q->ipqe_ip), i);
1.1 cgd 487: break;
488: }
1.25 ! cgd 489: nq = q->ipqe_q.le_next;
! 490: m_freem(dtom(q->ipqe_ip));
! 491: LIST_REMOVE(q, ipqe_q);
! 492: FREE(q, M_IPQ);
1.1 cgd 493: }
494:
495: insert:
496: /*
497: * Stick new segment in its place;
498: * check for complete reassembly.
499: */
1.25 ! cgd 500: if (p == NULL) {
! 501: LIST_INSERT_HEAD(&fp->ipq_fragq, ipqe, ipqe_q);
! 502: } else {
! 503: LIST_INSERT_AFTER(p, ipqe, ipqe_q);
! 504: }
1.1 cgd 505: next = 0;
1.25 ! cgd 506: for (p = NULL, q = fp->ipq_fragq.lh_first; q != NULL;
! 507: p = q, q = q->ipqe_q.le_next) {
! 508: if (q->ipqe_ip->ip_off != next)
1.1 cgd 509: return (0);
1.25 ! cgd 510: next += q->ipqe_ip->ip_len;
1.1 cgd 511: }
1.25 ! cgd 512: if (p->ipqe_mff)
1.1 cgd 513: return (0);
514:
515: /*
516: * Reassembly is complete; concatenate fragments.
517: */
1.25 ! cgd 518: q = fp->ipq_fragq.lh_first;
! 519: ip = q->ipqe_ip;
! 520: m = dtom(q->ipqe_ip);
1.1 cgd 521: t = m->m_next;
522: m->m_next = 0;
523: m_cat(m, t);
1.25 ! cgd 524: nq = q->ipqe_q.le_next;
! 525: FREE(q, M_IPQ);
! 526: for (q = nq; q != NULL; q = nq) {
! 527: t = dtom(q->ipqe_ip);
! 528: nq = q->ipqe_q.le_next;
! 529: FREE(q, M_IPQ);
1.1 cgd 530: m_cat(m, t);
531: }
532:
533: /*
534: * Create header for new ip packet by
535: * modifying header of first packet;
536: * dequeue and discard fragment reassembly header.
537: * Make header visible.
538: */
539: ip->ip_len = next;
1.25 ! cgd 540: ip->ip_src = fp->ipq_src;
! 541: ip->ip_dst = fp->ipq_dst;
! 542: LIST_REMOVE(fp, ipq_q);
1.1 cgd 543: (void) m_free(dtom(fp));
544: m->m_len += (ip->ip_hl << 2);
545: m->m_data -= (ip->ip_hl << 2);
546: /* some debugging cruft by sklower, below, will go away soon */
547: if (m->m_flags & M_PKTHDR) { /* XXX this should be done elsewhere */
548: register int plen = 0;
549: for (t = m; m; m = m->m_next)
550: plen += m->m_len;
551: t->m_pkthdr.len = plen;
552: }
1.25 ! cgd 553: return (ip);
1.1 cgd 554:
555: dropfrag:
556: ipstat.ips_fragdropped++;
557: m_freem(m);
1.25 ! cgd 558: FREE(ipqe, M_IPQ);
1.1 cgd 559: return (0);
560: }
561:
562: /*
563: * Free a fragment reassembly header and all
564: * associated datagrams.
565: */
1.8 mycroft 566: void
1.1 cgd 567: ip_freef(fp)
568: struct ipq *fp;
569: {
1.25 ! cgd 570: register struct ipqent *q, *p;
1.1 cgd 571:
1.25 ! cgd 572: for (q = fp->ipq_fragq.lh_first; q != NULL; q = p) {
! 573: p = q->ipqe_q.le_next;
! 574: m_freem(dtom(q->ipqe_ip));
! 575: LIST_REMOVE(q, ipqe_q);
! 576: FREE(q, M_IPQ);
1.1 cgd 577: }
1.25 ! cgd 578: LIST_REMOVE(fp, ipq_q);
1.1 cgd 579: (void) m_free(dtom(fp));
580: }
581:
582: /*
583: * IP timer processing;
584: * if a timer expires on a reassembly
585: * queue, discard it.
586: */
1.8 mycroft 587: void
1.1 cgd 588: ip_slowtimo()
589: {
1.25 ! cgd 590: register struct ipq *fp, *nfp;
1.24 mycroft 591: int s = splsoftnet();
1.1 cgd 592:
1.25 ! cgd 593: for (fp = ipq.lh_first; fp != NULL; fp = nfp) {
! 594: nfp = fp->ipq_q.le_next;
! 595: if (--fp->ipq_ttl == 0) {
1.1 cgd 596: ipstat.ips_fragtimeout++;
1.25 ! cgd 597: ip_freef(fp);
1.1 cgd 598: }
599: }
600: splx(s);
601: }
602:
603: /*
604: * Drain off all datagram fragments.
605: */
1.8 mycroft 606: void
1.1 cgd 607: ip_drain()
608: {
609:
1.25 ! cgd 610: while (ipq.lh_first != NULL) {
1.1 cgd 611: ipstat.ips_fragdropped++;
1.25 ! cgd 612: ip_freef(ipq.lh_first);
1.1 cgd 613: }
614: }
615:
616: /*
617: * Do option processing on a datagram,
618: * possibly discarding it if bad options are encountered,
619: * or forwarding it if source-routed.
620: * Returns 1 if packet has been forwarded/freed,
621: * 0 if the packet should be processed further.
622: */
1.8 mycroft 623: int
1.1 cgd 624: ip_dooptions(m)
625: struct mbuf *m;
626: {
627: register struct ip *ip = mtod(m, struct ip *);
628: register u_char *cp;
629: register struct ip_timestamp *ipt;
630: register struct in_ifaddr *ia;
631: int opt, optlen, cnt, off, code, type = ICMP_PARAMPROB, forward = 0;
1.13 mycroft 632: struct in_addr *sin, dst;
1.1 cgd 633: n_time ntime;
634:
1.13 mycroft 635: dst = ip->ip_dst;
1.1 cgd 636: cp = (u_char *)(ip + 1);
637: cnt = (ip->ip_hl << 2) - sizeof (struct ip);
638: for (; cnt > 0; cnt -= optlen, cp += optlen) {
639: opt = cp[IPOPT_OPTVAL];
640: if (opt == IPOPT_EOL)
641: break;
642: if (opt == IPOPT_NOP)
643: optlen = 1;
644: else {
645: optlen = cp[IPOPT_OLEN];
646: if (optlen <= 0 || optlen > cnt) {
647: code = &cp[IPOPT_OLEN] - (u_char *)ip;
648: goto bad;
649: }
650: }
651: switch (opt) {
652:
653: default:
654: break;
655:
656: /*
657: * Source routing with record.
658: * Find interface with current destination address.
659: * If none on this machine then drop if strictly routed,
660: * or do nothing if loosely routed.
661: * Record interface address and bring up next address
662: * component. If strictly routed make sure next
663: * address is on directly accessible net.
664: */
665: case IPOPT_LSRR:
666: case IPOPT_SSRR:
667: if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) {
668: code = &cp[IPOPT_OFFSET] - (u_char *)ip;
669: goto bad;
670: }
671: ipaddr.sin_addr = ip->ip_dst;
1.19 mycroft 672: ia = ifatoia(ifa_ifwithaddr(sintosa(&ipaddr)));
1.1 cgd 673: if (ia == 0) {
674: if (opt == IPOPT_SSRR) {
675: type = ICMP_UNREACH;
676: code = ICMP_UNREACH_SRCFAIL;
677: goto bad;
678: }
679: /*
680: * Loose routing, and not at next destination
681: * yet; nothing to do except forward.
682: */
683: break;
684: }
685: off--; /* 0 origin */
686: if (off > optlen - sizeof(struct in_addr)) {
687: /*
688: * End of source route. Should be for us.
689: */
690: save_rte(cp, ip->ip_src);
691: break;
692: }
693: /*
694: * locate outgoing interface
695: */
696: bcopy((caddr_t)(cp + off), (caddr_t)&ipaddr.sin_addr,
697: sizeof(ipaddr.sin_addr));
698: if (opt == IPOPT_SSRR) {
699: #define INA struct in_ifaddr *
700: #define SA struct sockaddr *
701: if ((ia = (INA)ifa_ifwithdstaddr((SA)&ipaddr)) == 0)
1.13 mycroft 702: ia = (INA)ifa_ifwithnet((SA)&ipaddr);
1.1 cgd 703: } else
704: ia = ip_rtaddr(ipaddr.sin_addr);
705: if (ia == 0) {
706: type = ICMP_UNREACH;
707: code = ICMP_UNREACH_SRCFAIL;
708: goto bad;
709: }
710: ip->ip_dst = ipaddr.sin_addr;
1.20 mycroft 711: bcopy((caddr_t)&ia->ia_addr.sin_addr,
1.1 cgd 712: (caddr_t)(cp + off), sizeof(struct in_addr));
713: cp[IPOPT_OFFSET] += sizeof(struct in_addr);
1.13 mycroft 714: /*
715: * Let ip_intr's mcast routing check handle mcast pkts
716: */
1.18 mycroft 717: forward = !IN_MULTICAST(ip->ip_dst.s_addr);
1.1 cgd 718: break;
719:
720: case IPOPT_RR:
721: if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) {
722: code = &cp[IPOPT_OFFSET] - (u_char *)ip;
723: goto bad;
724: }
725: /*
726: * If no space remains, ignore.
727: */
728: off--; /* 0 origin */
729: if (off > optlen - sizeof(struct in_addr))
730: break;
731: bcopy((caddr_t)(&ip->ip_dst), (caddr_t)&ipaddr.sin_addr,
732: sizeof(ipaddr.sin_addr));
733: /*
734: * locate outgoing interface; if we're the destination,
735: * use the incoming interface (should be same).
736: */
737: if ((ia = (INA)ifa_ifwithaddr((SA)&ipaddr)) == 0 &&
738: (ia = ip_rtaddr(ipaddr.sin_addr)) == 0) {
739: type = ICMP_UNREACH;
740: code = ICMP_UNREACH_HOST;
741: goto bad;
742: }
1.20 mycroft 743: bcopy((caddr_t)&ia->ia_addr.sin_addr,
1.1 cgd 744: (caddr_t)(cp + off), sizeof(struct in_addr));
745: cp[IPOPT_OFFSET] += sizeof(struct in_addr);
746: break;
747:
748: case IPOPT_TS:
749: code = cp - (u_char *)ip;
750: ipt = (struct ip_timestamp *)cp;
751: if (ipt->ipt_len < 5)
752: goto bad;
1.15 cgd 753: if (ipt->ipt_ptr > ipt->ipt_len - sizeof (int32_t)) {
1.1 cgd 754: if (++ipt->ipt_oflw == 0)
755: goto bad;
756: break;
757: }
758: sin = (struct in_addr *)(cp + ipt->ipt_ptr - 1);
759: switch (ipt->ipt_flg) {
760:
761: case IPOPT_TS_TSONLY:
762: break;
763:
764: case IPOPT_TS_TSANDADDR:
765: if (ipt->ipt_ptr + sizeof(n_time) +
766: sizeof(struct in_addr) > ipt->ipt_len)
767: goto bad;
1.13 mycroft 768: ipaddr.sin_addr = dst;
769: ia = (INA)ifaof_ifpforaddr((SA)&ipaddr,
770: m->m_pkthdr.rcvif);
771: if (ia == 0)
772: continue;
1.20 mycroft 773: bcopy((caddr_t)&ia->ia_addr.sin_addr,
1.1 cgd 774: (caddr_t)sin, sizeof(struct in_addr));
775: ipt->ipt_ptr += sizeof(struct in_addr);
776: break;
777:
778: case IPOPT_TS_PRESPEC:
779: if (ipt->ipt_ptr + sizeof(n_time) +
780: sizeof(struct in_addr) > ipt->ipt_len)
781: goto bad;
782: bcopy((caddr_t)sin, (caddr_t)&ipaddr.sin_addr,
783: sizeof(struct in_addr));
784: if (ifa_ifwithaddr((SA)&ipaddr) == 0)
785: continue;
786: ipt->ipt_ptr += sizeof(struct in_addr);
787: break;
788:
789: default:
790: goto bad;
791: }
792: ntime = iptime();
793: bcopy((caddr_t)&ntime, (caddr_t)cp + ipt->ipt_ptr - 1,
794: sizeof(n_time));
795: ipt->ipt_ptr += sizeof(n_time);
796: }
797: }
798: if (forward) {
799: ip_forward(m, 1);
800: return (1);
1.13 mycroft 801: }
802: return (0);
1.1 cgd 803: bad:
1.13 mycroft 804: ip->ip_len -= ip->ip_hl << 2; /* XXX icmp_error adds in hdr length */
805: icmp_error(m, type, code, 0, 0);
806: ipstat.ips_badoptions++;
1.1 cgd 807: return (1);
808: }
809:
810: /*
811: * Given address of next destination (final or next hop),
812: * return internet address info of interface to be used to get there.
813: */
814: struct in_ifaddr *
815: ip_rtaddr(dst)
816: struct in_addr dst;
817: {
818: register struct sockaddr_in *sin;
819:
1.19 mycroft 820: sin = satosin(&ipforward_rt.ro_dst);
1.1 cgd 821:
822: if (ipforward_rt.ro_rt == 0 || dst.s_addr != sin->sin_addr.s_addr) {
823: if (ipforward_rt.ro_rt) {
824: RTFREE(ipforward_rt.ro_rt);
825: ipforward_rt.ro_rt = 0;
826: }
827: sin->sin_family = AF_INET;
828: sin->sin_len = sizeof(*sin);
829: sin->sin_addr = dst;
830:
831: rtalloc(&ipforward_rt);
832: }
833: if (ipforward_rt.ro_rt == 0)
834: return ((struct in_ifaddr *)0);
1.19 mycroft 835: return (ifatoia(ipforward_rt.ro_rt->rt_ifa));
1.1 cgd 836: }
837:
838: /*
839: * Save incoming source route for use in replies,
840: * to be picked up later by ip_srcroute if the receiver is interested.
841: */
1.13 mycroft 842: void
1.1 cgd 843: save_rte(option, dst)
844: u_char *option;
845: struct in_addr dst;
846: {
847: unsigned olen;
848:
849: olen = option[IPOPT_OLEN];
850: #ifdef DIAGNOSTIC
851: if (ipprintfs)
852: printf("save_rte: olen %d\n", olen);
853: #endif
854: if (olen > sizeof(ip_srcrt) - (1 + sizeof(dst)))
855: return;
856: bcopy((caddr_t)option, (caddr_t)ip_srcrt.srcopt, olen);
857: ip_nhops = (olen - IPOPT_OFFSET - 1) / sizeof(struct in_addr);
858: ip_srcrt.dst = dst;
859: }
860:
861: /*
862: * Retrieve incoming source route for use in replies,
863: * in the same form used by setsockopt.
864: * The first hop is placed before the options, will be removed later.
865: */
866: struct mbuf *
867: ip_srcroute()
868: {
869: register struct in_addr *p, *q;
870: register struct mbuf *m;
871:
872: if (ip_nhops == 0)
873: return ((struct mbuf *)0);
874: m = m_get(M_DONTWAIT, MT_SOOPTS);
875: if (m == 0)
876: return ((struct mbuf *)0);
877:
1.13 mycroft 878: #define OPTSIZ (sizeof(ip_srcrt.nop) + sizeof(ip_srcrt.srcopt))
1.1 cgd 879:
880: /* length is (nhops+1)*sizeof(addr) + sizeof(nop + srcrt header) */
881: m->m_len = ip_nhops * sizeof(struct in_addr) + sizeof(struct in_addr) +
882: OPTSIZ;
883: #ifdef DIAGNOSTIC
884: if (ipprintfs)
885: printf("ip_srcroute: nhops %d mlen %d", ip_nhops, m->m_len);
886: #endif
887:
888: /*
889: * First save first hop for return route
890: */
891: p = &ip_srcrt.route[ip_nhops - 1];
892: *(mtod(m, struct in_addr *)) = *p--;
893: #ifdef DIAGNOSTIC
894: if (ipprintfs)
895: printf(" hops %lx", ntohl(mtod(m, struct in_addr *)->s_addr));
896: #endif
897:
898: /*
899: * Copy option fields and padding (nop) to mbuf.
900: */
901: ip_srcrt.nop = IPOPT_NOP;
902: ip_srcrt.srcopt[IPOPT_OFFSET] = IPOPT_MINOFF;
903: bcopy((caddr_t)&ip_srcrt.nop,
904: mtod(m, caddr_t) + sizeof(struct in_addr), OPTSIZ);
905: q = (struct in_addr *)(mtod(m, caddr_t) +
906: sizeof(struct in_addr) + OPTSIZ);
907: #undef OPTSIZ
908: /*
909: * Record return path as an IP source route,
910: * reversing the path (pointers are now aligned).
911: */
912: while (p >= ip_srcrt.route) {
913: #ifdef DIAGNOSTIC
914: if (ipprintfs)
915: printf(" %lx", ntohl(q->s_addr));
916: #endif
917: *q++ = *p--;
918: }
919: /*
920: * Last hop goes to final destination.
921: */
922: *q = ip_srcrt.dst;
923: #ifdef DIAGNOSTIC
924: if (ipprintfs)
925: printf(" %lx\n", ntohl(q->s_addr));
926: #endif
927: return (m);
928: }
929:
930: /*
931: * Strip out IP options, at higher
932: * level protocol in the kernel.
933: * Second argument is buffer to which options
934: * will be moved, and return value is their length.
935: * XXX should be deleted; last arg currently ignored.
936: */
1.8 mycroft 937: void
1.1 cgd 938: ip_stripoptions(m, mopt)
939: register struct mbuf *m;
940: struct mbuf *mopt;
941: {
942: register int i;
943: struct ip *ip = mtod(m, struct ip *);
944: register caddr_t opts;
945: int olen;
946:
947: olen = (ip->ip_hl<<2) - sizeof (struct ip);
948: opts = (caddr_t)(ip + 1);
949: i = m->m_len - (sizeof (struct ip) + olen);
950: bcopy(opts + olen, opts, (unsigned)i);
951: m->m_len -= olen;
952: if (m->m_flags & M_PKTHDR)
953: m->m_pkthdr.len -= olen;
954: ip->ip_hl = sizeof(struct ip) >> 2;
955: }
956:
1.23 mycroft 957: int inetctlerrmap[PRC_NCMDS] = {
1.1 cgd 958: 0, 0, 0, 0,
959: 0, EMSGSIZE, EHOSTDOWN, EHOSTUNREACH,
960: EHOSTUNREACH, EHOSTUNREACH, ECONNREFUSED, ECONNREFUSED,
961: EMSGSIZE, EHOSTUNREACH, 0, 0,
962: 0, 0, 0, 0,
963: ENOPROTOOPT
964: };
965:
966: /*
967: * Forward a packet. If some error occurs return the sender
968: * an icmp packet. Note we can't always generate a meaningful
969: * icmp message because icmp doesn't have a large enough repertoire
970: * of codes and types.
971: *
972: * If not forwarding, just drop the packet. This could be confusing
973: * if ipforwarding was zero but some routing protocol was advancing
974: * us as a gateway to somewhere. However, we must let the routing
975: * protocol deal with that.
976: *
977: * The srcrt parameter indicates whether the packet is being forwarded
978: * via a source route.
979: */
1.13 mycroft 980: void
1.1 cgd 981: ip_forward(m, srcrt)
982: struct mbuf *m;
983: int srcrt;
984: {
985: register struct ip *ip = mtod(m, struct ip *);
986: register struct sockaddr_in *sin;
987: register struct rtentry *rt;
988: int error, type = 0, code;
989: struct mbuf *mcopy;
1.13 mycroft 990: n_long dest;
991: struct ifnet *destifp;
1.1 cgd 992:
1.13 mycroft 993: dest = 0;
1.1 cgd 994: #ifdef DIAGNOSTIC
995: if (ipprintfs)
996: printf("forward: src %x dst %x ttl %x\n", ip->ip_src,
997: ip->ip_dst, ip->ip_ttl);
998: #endif
999: if (m->m_flags & M_BCAST || in_canforward(ip->ip_dst) == 0) {
1000: ipstat.ips_cantforward++;
1001: m_freem(m);
1002: return;
1003: }
1004: HTONS(ip->ip_id);
1005: if (ip->ip_ttl <= IPTTLDEC) {
1.13 mycroft 1006: icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, dest, 0);
1.1 cgd 1007: return;
1008: }
1009: ip->ip_ttl -= IPTTLDEC;
1010:
1.19 mycroft 1011: sin = satosin(&ipforward_rt.ro_dst);
1.1 cgd 1012: if ((rt = ipforward_rt.ro_rt) == 0 ||
1013: ip->ip_dst.s_addr != sin->sin_addr.s_addr) {
1014: if (ipforward_rt.ro_rt) {
1015: RTFREE(ipforward_rt.ro_rt);
1016: ipforward_rt.ro_rt = 0;
1017: }
1018: sin->sin_family = AF_INET;
1019: sin->sin_len = sizeof(*sin);
1020: sin->sin_addr = ip->ip_dst;
1021:
1022: rtalloc(&ipforward_rt);
1023: if (ipforward_rt.ro_rt == 0) {
1.13 mycroft 1024: icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, dest, 0);
1.1 cgd 1025: return;
1026: }
1027: rt = ipforward_rt.ro_rt;
1028: }
1029:
1030: /*
1031: * Save at most 64 bytes of the packet in case
1032: * we need to generate an ICMP message to the src.
1033: */
1034: mcopy = m_copy(m, 0, imin((int)ip->ip_len, 64));
1035:
1036: /*
1037: * If forwarding packet using same interface that it came in on,
1038: * perhaps should send a redirect to sender to shortcut a hop.
1039: * Only send redirect if source is sending directly to us,
1040: * and if packet was not source routed (or has any options).
1041: * Also, don't send redirect if forwarding using a default route
1042: * or a route modified by a redirect.
1043: */
1044: if (rt->rt_ifp == m->m_pkthdr.rcvif &&
1045: (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0 &&
1046: satosin(rt_key(rt))->sin_addr.s_addr != 0 &&
1047: ipsendredirects && !srcrt) {
1.19 mycroft 1048: if (rt->rt_ifa &&
1049: (ip->ip_src.s_addr & ifatoia(rt->rt_ifa)->ia_subnetmask) ==
1050: ifatoia(rt->rt_ifa)->ia_subnet) {
1.1 cgd 1051: if (rt->rt_flags & RTF_GATEWAY)
1.13 mycroft 1052: dest = satosin(rt->rt_gateway)->sin_addr.s_addr;
1.1 cgd 1053: else
1.13 mycroft 1054: dest = ip->ip_dst.s_addr;
1055: /* Router requirements says to only send host redirects */
1.1 cgd 1056: type = ICMP_REDIRECT;
1.13 mycroft 1057: code = ICMP_REDIRECT_HOST;
1.1 cgd 1058: #ifdef DIAGNOSTIC
1059: if (ipprintfs)
1.15 cgd 1060: printf("redirect (%d) to %lx\n", code, (u_int32_t)dest);
1.1 cgd 1061: #endif
1062: }
1063: }
1064:
1.13 mycroft 1065: error = ip_output(m, (struct mbuf *)0, &ipforward_rt, IP_FORWARDING
1.9 mycroft 1066: #ifdef DIRECTED_BROADCAST
1.13 mycroft 1067: | IP_ALLOWBROADCAST
1.9 mycroft 1068: #endif
1.13 mycroft 1069: , 0);
1.1 cgd 1070: if (error)
1071: ipstat.ips_cantforward++;
1072: else {
1073: ipstat.ips_forward++;
1074: if (type)
1075: ipstat.ips_redirectsent++;
1076: else {
1077: if (mcopy)
1078: m_freem(mcopy);
1079: return;
1080: }
1081: }
1082: if (mcopy == NULL)
1083: return;
1.13 mycroft 1084: destifp = NULL;
1085:
1.1 cgd 1086: switch (error) {
1087:
1088: case 0: /* forwarded, but need redirect */
1089: /* type, code set above */
1090: break;
1091:
1092: case ENETUNREACH: /* shouldn't happen, checked above */
1093: case EHOSTUNREACH:
1094: case ENETDOWN:
1095: case EHOSTDOWN:
1096: default:
1097: type = ICMP_UNREACH;
1098: code = ICMP_UNREACH_HOST;
1099: break;
1100:
1101: case EMSGSIZE:
1102: type = ICMP_UNREACH;
1103: code = ICMP_UNREACH_NEEDFRAG;
1.13 mycroft 1104: if (ipforward_rt.ro_rt)
1105: destifp = ipforward_rt.ro_rt->rt_ifp;
1.1 cgd 1106: ipstat.ips_cantfrag++;
1107: break;
1108:
1109: case ENOBUFS:
1110: type = ICMP_SOURCEQUENCH;
1111: code = 0;
1112: break;
1113: }
1.13 mycroft 1114: icmp_error(mcopy, type, code, dest, destifp);
1115: }
1116:
1117: int
1118: ip_sysctl(name, namelen, oldp, oldlenp, newp, newlen)
1119: int *name;
1120: u_int namelen;
1121: void *oldp;
1122: size_t *oldlenp;
1123: void *newp;
1124: size_t newlen;
1125: {
1126: /* All sysctl names at this level are terminal. */
1127: if (namelen != 1)
1128: return (ENOTDIR);
1129:
1130: switch (name[0]) {
1131: case IPCTL_FORWARDING:
1132: return (sysctl_int(oldp, oldlenp, newp, newlen, &ipforwarding));
1133: case IPCTL_SENDREDIRECTS:
1134: return (sysctl_int(oldp, oldlenp, newp, newlen,
1135: &ipsendredirects));
1136: case IPCTL_DEFTTL:
1137: return (sysctl_int(oldp, oldlenp, newp, newlen, &ip_defttl));
1138: #ifdef notyet
1139: case IPCTL_DEFMTU:
1140: return (sysctl_int(oldp, oldlenp, newp, newlen, &ip_mtu));
1141: #endif
1142: default:
1143: return (EOPNOTSUPP);
1144: }
1145: /* NOTREACHED */
1.1 cgd 1146: }
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