Context Navigation

source: rtems/cpukit/libnetworking/netinet/ip_icmp.c @ 5d5f23b

4.104.114.84.95

Last change on this file since 5d5f23b was 39e6e65a, checked in by Joel Sherrill <joel.sherrill@…>, on 08/19/98 at 21:32:28
Base files
Property mode set to `100644`
File size: 18.1 KB

Line
1	/*
2	* Copyright (c) 1982, 1986, 1988, 1993
3	* The Regents of the University of California. 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	*
33	* @(#)ip_icmp.c 8.2 (Berkeley) 1/4/94
34	* $Id$
35	*/
36
37	#include <sys/param.h>
38	#include <sys/systm.h>
39	#include <sys/malloc.h>
40	#include <sys/mbuf.h>
41	#include <sys/protosw.h>
42	#include <sys/socket.h>
43	#include <sys/time.h>
44	#include <sys/kernel.h>
45	#include <sys/socket.h>
46	#include <sys/sysctl.h>
47
48	#include <net/if.h>
49	#include <net/route.h>
50
51	#define _IP_VHL
52	#include <netinet/in.h>
53	#include <netinet/in_systm.h>
54	#include <netinet/in_var.h>
55	#include <netinet/ip.h>
56	#include <netinet/ip_icmp.h>
57	#include <netinet/ip_var.h>
58	#include <netinet/icmp_var.h>
59
60	/*
61	* ICMP routines: error generation, receive packet processing, and
62	* routines to turnaround packets back to the originator, and
63	* host table maintenance routines.
64	*/
65
66	struct icmpstat icmpstat;
67	SYSCTL_STRUCT(_net_inet_icmp, ICMPCTL_STATS, stats, CTLFLAG_RD,
68	&icmpstat, icmpstat, "");
69
70	static int icmpmaskrepl = 0;
71	SYSCTL_INT(_net_inet_icmp, ICMPCTL_MASKREPL, maskrepl, CTLFLAG_RW,
72	&icmpmaskrepl, 0, "");
73
74	static int icmpbmcastecho = 1;
75	SYSCTL_INT(_net_inet_icmp, OID_AUTO, bmcastecho, CTLFLAG_RW, &icmpbmcastecho,
76	0, "");
77
78	#ifdef ICMPPRINTFS
79	int icmpprintfs = 0;
80	#endif
81
82	static void icmp_reflect __P((struct mbuf *));
83	static void icmp_send __P((struct mbuf , struct mbuf ));
84	static int ip_next_mtu __P((int, int));
85
86	extern struct protosw inetsw[];
87
88	/*
89	* Generate an error packet of type error
90	* in response to bad packet ip.
91	*/
92	void
93	icmp_error(n, type, code, dest, destifp)
94	struct mbuf *n;
95	int type, code;
96	n_long dest;
97	struct ifnet *destifp;
98	{
99	register struct ip oip = mtod(n, struct ip ), *nip;
100	register unsigned oiplen = IP_VHL_HL(oip->ip_vhl) << 2;
101	register struct icmp *icp;
102	register struct mbuf *m;
103	unsigned icmplen;
104
105	#ifdef ICMPPRINTFS
106	if (icmpprintfs)
107	printf("icmp_error(%p, %x, %d)\n", oip, type, code);
108	#endif
109	if (type != ICMP_REDIRECT)
110	icmpstat.icps_error++;
111	/*
112	* Don't send error if not the first fragment of message.
113	* Don't error if the old packet protocol was ICMP
114	* error message, only known informational types.
115	*/
116	if (oip->ip_off &~ (IP_MF\|IP_DF))
117	goto freeit;
118	if (oip->ip_p == IPPROTO_ICMP && type != ICMP_REDIRECT &&
119	n->m_len >= oiplen + ICMP_MINLEN &&
120	!ICMP_INFOTYPE(((struct icmp *)((caddr_t)oip + oiplen))->icmp_type)) {
121	icmpstat.icps_oldicmp++;
122	goto freeit;
123	}
124	/* Don't send error in response to a multicast or broadcast packet */
125	if (n->m_flags & (M_BCAST\|M_MCAST))
126	goto freeit;
127	/*
128	* First, formulate icmp message
129	*/
130	m = m_gethdr(M_DONTWAIT, MT_HEADER);
131	if (m == NULL)
132	goto freeit;
133	icmplen = oiplen + min(8, oip->ip_len);
134	m->m_len = icmplen + ICMP_MINLEN;
135	MH_ALIGN(m, m->m_len);
136	icp = mtod(m, struct icmp *);
137	if ((u_int)type > ICMP_MAXTYPE)
138	panic("icmp_error");
139	icmpstat.icps_outhist[type]++;
140	icp->icmp_type = type;
141	if (type == ICMP_REDIRECT)
142	icp->icmp_gwaddr.s_addr = dest;
143	else {
144	icp->icmp_void = 0;
145	/*
146	* The following assignments assume an overlay with the
147	* zeroed icmp_void field.
148	*/
149	if (type == ICMP_PARAMPROB) {
150	icp->icmp_pptr = code;
151	code = 0;
152	} else if (type == ICMP_UNREACH &&
153	code == ICMP_UNREACH_NEEDFRAG && destifp) {
154	icp->icmp_nextmtu = htons(destifp->if_mtu);
155	}
156	}
157
158	icp->icmp_code = code;
159	bcopy((caddr_t)oip, (caddr_t)&icp->icmp_ip, icmplen);
160	nip = &icp->icmp_ip;
161	nip->ip_len = htons((u_short)(nip->ip_len + oiplen));
162
163	/*
164	* Now, copy old ip header (without options)
165	* in front of icmp message.
166	*/
167	if (m->m_data - sizeof(struct ip) < m->m_pktdat)
168	panic("icmp len");
169	m->m_data -= sizeof(struct ip);
170	m->m_len += sizeof(struct ip);
171	m->m_pkthdr.len = m->m_len;
172	m->m_pkthdr.rcvif = n->m_pkthdr.rcvif;
173	nip = mtod(m, struct ip *);
174	bcopy((caddr_t)oip, (caddr_t)nip, sizeof(struct ip));
175	nip->ip_len = m->m_len;
176	nip->ip_vhl = IP_VHL_BORING;
177	nip->ip_p = IPPROTO_ICMP;
178	nip->ip_tos = 0;
179	icmp_reflect(m);
180
181	freeit:
182	m_freem(n);
183	}
184
185	static struct sockaddr_in icmpsrc = { sizeof (struct sockaddr_in), AF_INET };
186	static struct sockaddr_in icmpdst = { sizeof (struct sockaddr_in), AF_INET };
187	static struct sockaddr_in icmpgw = { sizeof (struct sockaddr_in), AF_INET };
188
189	/*
190	* Process a received ICMP message.
191	*/
192	void
193	icmp_input(m, hlen)
194	register struct mbuf *m;
195	int hlen;
196	{
197	register struct icmp *icp;
198	register struct ip ip = mtod(m, struct ip );
199	int icmplen = ip->ip_len;
200	register int i;
201	struct in_ifaddr *ia;
202	void (ctlfunc) __P((int, struct sockaddr , void *));
203	int code;
204
205	/*
206	* Locate icmp structure in mbuf, and check
207	* that not corrupted and of at least minimum length.
208	*/
209	#ifdef ICMPPRINTFS
210	if (icmpprintfs) {
211	char buf[4 * sizeof "123"];
212	strcpy(buf, inet_ntoa(ip->ip_src));
213	printf("icmp_input from %s to %s, len %d\n",
214	buf, inet_ntoa(ip->ip_dst), icmplen);
215	}
216	#endif
217	if (icmplen < ICMP_MINLEN) {
218	icmpstat.icps_tooshort++;
219	goto freeit;
220	}
221	i = hlen + min(icmplen, ICMP_ADVLENMIN);
222	if (m->m_len < i && (m = m_pullup(m, i)) == 0) {
223	icmpstat.icps_tooshort++;
224	return;
225	}
226	ip = mtod(m, struct ip *);
227	m->m_len -= hlen;
228	m->m_data += hlen;
229	icp = mtod(m, struct icmp *);
230	if (in_cksum(m, icmplen)) {
231	icmpstat.icps_checksum++;
232	goto freeit;
233	}
234	m->m_len += hlen;
235	m->m_data -= hlen;
236
237	#ifdef ICMPPRINTFS
238	if (icmpprintfs)
239	printf("icmp_input, type %d code %d\n", icp->icmp_type,
240	icp->icmp_code);
241	#endif
242
243	/*
244	* Message type specific processing.
245	*/
246	if (icp->icmp_type > ICMP_MAXTYPE)
247	goto raw;
248	icmpstat.icps_inhist[icp->icmp_type]++;
249	code = icp->icmp_code;
250	switch (icp->icmp_type) {
251
252	case ICMP_UNREACH:
253	switch (code) {
254	case ICMP_UNREACH_NET:
255	case ICMP_UNREACH_HOST:
256	case ICMP_UNREACH_PROTOCOL:
257	case ICMP_UNREACH_PORT:
258	case ICMP_UNREACH_SRCFAIL:
259	code += PRC_UNREACH_NET;
260	break;
261
262	case ICMP_UNREACH_NEEDFRAG:
263	code = PRC_MSGSIZE;
264	break;
265
266	case ICMP_UNREACH_NET_UNKNOWN:
267	case ICMP_UNREACH_NET_PROHIB:
268	case ICMP_UNREACH_TOSNET:
269	code = PRC_UNREACH_NET;
270	break;
271
272	case ICMP_UNREACH_HOST_UNKNOWN:
273	case ICMP_UNREACH_ISOLATED:
274	case ICMP_UNREACH_HOST_PROHIB:
275	case ICMP_UNREACH_TOSHOST:
276	code = PRC_UNREACH_HOST;
277	break;
278
279	case ICMP_UNREACH_FILTER_PROHIB:
280	case ICMP_UNREACH_HOST_PRECEDENCE:
281	case ICMP_UNREACH_PRECEDENCE_CUTOFF:
282	code = PRC_UNREACH_PORT;
283	break;
284
285	default:
286	goto badcode;
287	}
288	goto deliver;
289
290	case ICMP_TIMXCEED:
291	if (code > 1)
292	goto badcode;
293	code += PRC_TIMXCEED_INTRANS;
294	goto deliver;
295
296	case ICMP_PARAMPROB:
297	if (code > 1)
298	goto badcode;
299	code = PRC_PARAMPROB;
300	goto deliver;
301
302	case ICMP_SOURCEQUENCH:
303	if (code)
304	goto badcode;
305	code = PRC_QUENCH;
306	deliver:
307	/*
308	* Problem with datagram; advise higher level routines.
309	*/
310	if (icmplen < ICMP_ADVLENMIN \|\| icmplen < ICMP_ADVLEN(icp) \|\|
311	IP_VHL_HL(icp->icmp_ip.ip_vhl) < (sizeof(struct ip) >> 2)) {
312	icmpstat.icps_badlen++;
313	goto freeit;
314	}
315	NTOHS(icp->icmp_ip.ip_len);
316	/* Discard ICMP's in response to multicast packets */
317	if (IN_MULTICAST(ntohl(icp->icmp_ip.ip_dst.s_addr)))
318	goto badcode;
319	#ifdef ICMPPRINTFS
320	if (icmpprintfs)
321	printf("deliver to protocol %d\n", icp->icmp_ip.ip_p);
322	#endif
323	icmpsrc.sin_addr = icp->icmp_ip.ip_dst;
324	#if 1
325	/*
326	* MTU discovery:
327	* If we got a needfrag and there is a host route to the
328	* original destination, and the MTU is not locked, then
329	* set the MTU in the route to the suggested new value
330	* (if given) and then notify as usual. The ULPs will
331	* notice that the MTU has changed and adapt accordingly.
332	* If no new MTU was suggested, then we guess a new one
333	* less than the current value. If the new MTU is
334	* unreasonably small (arbitrarily set at 296), then
335	* we reset the MTU to the interface value and enable the
336	* lock bit, indicating that we are no longer doing MTU
337	* discovery.
338	*/
339	if (code == PRC_MSGSIZE) {
340	struct rtentry *rt;
341	int mtu;
342
343	rt = rtalloc1((struct sockaddr *)&icmpsrc, 0,
344	RTF_CLONING \| RTF_PRCLONING);
345	if (rt && (rt->rt_flags & RTF_HOST)
346	&& !(rt->rt_rmx.rmx_locks & RTV_MTU)) {
347	mtu = ntohs(icp->icmp_nextmtu);
348	if (!mtu)
349	mtu = ip_next_mtu(rt->rt_rmx.rmx_mtu,
350	1);
351	#ifdef DEBUG_MTUDISC
352	printf("MTU for %s reduced to %d\n",
353	inet_ntoa(icmpsrc.sin_addr), mtu);
354	#endif
355	if (mtu < 296) {
356	/* rt->rt_rmx.rmx_mtu =
357	rt->rt_ifp->if_mtu; */
358	rt->rt_rmx.rmx_locks \|= RTV_MTU;
359	} else if (rt->rt_rmx.rmx_mtu > mtu) {
360	rt->rt_rmx.rmx_mtu = mtu;
361	}
362	}
363	if (rt)
364	RTFREE(rt);
365	}
366
367	#endif
368	ctlfunc = inetsw[ip_protox[icp->icmp_ip.ip_p]].pr_ctlinput;
369	if (ctlfunc)
370	(ctlfunc)(code, (struct sockaddr )&icmpsrc,
371	(void *)&icp->icmp_ip);
372	break;
373
374	badcode:
375	icmpstat.icps_badcode++;
376	break;
377
378	case ICMP_ECHO:
379	if (!icmpbmcastecho
380	&& (m->m_flags & (M_MCAST \| M_BCAST)) != 0
381	&& IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) {
382	icmpstat.icps_bmcastecho++;
383	break;
384	}
385	icp->icmp_type = ICMP_ECHOREPLY;
386	goto reflect;
387
388	case ICMP_TSTAMP:
389	if (!icmpbmcastecho
390	&& (m->m_flags & (M_MCAST \| M_BCAST)) != 0
391	&& IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) {
392	icmpstat.icps_bmcasttstamp++;
393	break;
394	}
395	if (icmplen < ICMP_TSLEN) {
396	icmpstat.icps_badlen++;
397	break;
398	}
399	icp->icmp_type = ICMP_TSTAMPREPLY;
400	icp->icmp_rtime = iptime();
401	icp->icmp_ttime = icp->icmp_rtime; /* bogus, do later! */
402	goto reflect;
403
404	case ICMP_MASKREQ:
405	#define satosin(sa) ((struct sockaddr_in *)(sa))
406	if (icmpmaskrepl == 0)
407	break;
408	/*
409	* We are not able to respond with all ones broadcast
410	* unless we receive it over a point-to-point interface.
411	*/
412	if (icmplen < ICMP_MASKLEN)
413	break;
414	switch (ip->ip_dst.s_addr) {
415
416	case INADDR_BROADCAST:
417	case INADDR_ANY:
418	icmpdst.sin_addr = ip->ip_src;
419	break;
420
421	default:
422	icmpdst.sin_addr = ip->ip_dst;
423	}
424	ia = (struct in_ifaddr *)ifaof_ifpforaddr(
425	(struct sockaddr *)&icmpdst, m->m_pkthdr.rcvif);
426	if (ia == 0)
427	break;
428	if (ia->ia_ifp == 0)
429	break;
430	icp->icmp_type = ICMP_MASKREPLY;
431	icp->icmp_mask = ia->ia_sockmask.sin_addr.s_addr;
432	if (ip->ip_src.s_addr == 0) {
433	if (ia->ia_ifp->if_flags & IFF_BROADCAST)
434	ip->ip_src = satosin(&ia->ia_broadaddr)->sin_addr;
435	else if (ia->ia_ifp->if_flags & IFF_POINTOPOINT)
436	ip->ip_src = satosin(&ia->ia_dstaddr)->sin_addr;
437	}
438	reflect:
439	ip->ip_len += hlen; /* since ip_input deducts this */
440	icmpstat.icps_reflect++;
441	icmpstat.icps_outhist[icp->icmp_type]++;
442	icmp_reflect(m);
443	return;
444
445	case ICMP_REDIRECT:
446	if (code > 3)
447	goto badcode;
448	if (icmplen < ICMP_ADVLENMIN \|\| icmplen < ICMP_ADVLEN(icp) \|\|
449	IP_VHL_HL(icp->icmp_ip.ip_vhl) < (sizeof(struct ip) >> 2)) {
450	icmpstat.icps_badlen++;
451	break;
452	}
453	/*
454	* Short circuit routing redirects to force
455	* immediate change in the kernel's routing
456	* tables. The message is also handed to anyone
457	* listening on a raw socket (e.g. the routing
458	* daemon for use in updating its tables).
459	*/
460	icmpgw.sin_addr = ip->ip_src;
461	icmpdst.sin_addr = icp->icmp_gwaddr;
462	#ifdef ICMPPRINTFS
463	if (icmpprintfs) {
464	char buf[4 * sizeof "123"];
465	strcpy(buf, inet_ntoa(icp->icmp_ip.ip_dst));
466
467	printf("redirect dst %s to %s\n",
468	buf, inet_ntoa(icp->icmp_gwaddr));
469	}
470	#endif
471	icmpsrc.sin_addr = icp->icmp_ip.ip_dst;
472	rtredirect((struct sockaddr *)&icmpsrc,
473	(struct sockaddr *)&icmpdst,
474	(struct sockaddr *)0, RTF_GATEWAY \| RTF_HOST,
475	(struct sockaddr )&icmpgw, (struct rtentry *)0);
476	pfctlinput(PRC_REDIRECT_HOST, (struct sockaddr *)&icmpsrc);
477	break;
478
479	/*
480	* No kernel processing for the following;
481	* just fall through to send to raw listener.
482	*/
483	case ICMP_ECHOREPLY:
484	case ICMP_ROUTERADVERT:
485	case ICMP_ROUTERSOLICIT:
486	case ICMP_TSTAMPREPLY:
487	case ICMP_IREQREPLY:
488	case ICMP_MASKREPLY:
489	default:
490	break;
491	}
492
493	raw:
494	rip_input(m, hlen);
495	return;
496
497	freeit:
498	m_freem(m);
499	}
500
501	/*
502	* Reflect the ip packet back to the source
503	*/
504	static void
505	icmp_reflect(m)
506	struct mbuf *m;
507	{
508	register struct ip ip = mtod(m, struct ip );
509	register struct in_ifaddr *ia;
510	struct in_addr t;
511	struct mbuf *opts = 0;
512	int optlen = (IP_VHL_HL(ip->ip_vhl) << 2) - sizeof(struct ip);
513
514	if (!in_canforward(ip->ip_src) &&
515	((ntohl(ip->ip_src.s_addr) & IN_CLASSA_NET) !=
516	(IN_LOOPBACKNET << IN_CLASSA_NSHIFT))) {
517	m_freem(m); /* Bad return address */
518	goto done; /* Ip_output() will check for broadcast */
519	}
520	t = ip->ip_dst;
521	ip->ip_dst = ip->ip_src;
522	/*
523	* If the incoming packet was addressed directly to us,
524	* use dst as the src for the reply. Otherwise (broadcast
525	* or anonymous), use the address which corresponds
526	* to the incoming interface.
527	*/
528	for (ia = in_ifaddr; ia; ia = ia->ia_next) {
529	if (t.s_addr == IA_SIN(ia)->sin_addr.s_addr)
530	break;
531	if (ia->ia_ifp && (ia->ia_ifp->if_flags & IFF_BROADCAST) &&
532	t.s_addr == satosin(&ia->ia_broadaddr)->sin_addr.s_addr)
533	break;
534	}
535	icmpdst.sin_addr = t;
536	if ((ia == (struct in_ifaddr *)0) && m->m_pkthdr.rcvif)
537	ia = (struct in_ifaddr *)ifaof_ifpforaddr(
538	(struct sockaddr *)&icmpdst, m->m_pkthdr.rcvif);
539	/*
540	* The following happens if the packet was not addressed to us,
541	* and was received on an interface with no IP address.
542	*/
543	if (ia == (struct in_ifaddr *)0)
544	ia = in_ifaddr;
545	t = IA_SIN(ia)->sin_addr;
546	ip->ip_src = t;
547	ip->ip_ttl = MAXTTL;
548
549	if (optlen > 0) {
550	register u_char *cp;
551	int opt, cnt;
552	u_int len;
553
554	/*
555	* Retrieve any source routing from the incoming packet;
556	* add on any record-route or timestamp options.
557	*/
558	cp = (u_char *) (ip + 1);
559	if ((opts = ip_srcroute()) == 0 &&
560	(opts = m_gethdr(M_DONTWAIT, MT_HEADER))) {
561	opts->m_len = sizeof(struct in_addr);
562	mtod(opts, struct in_addr *)->s_addr = 0;
563	}
564	if (opts) {
565	#ifdef ICMPPRINTFS
566	if (icmpprintfs)
567	printf("icmp_reflect optlen %d rt %d => ",
568	optlen, opts->m_len);
569	#endif
570	for (cnt = optlen; cnt > 0; cnt -= len, cp += len) {
571	opt = cp[IPOPT_OPTVAL];
572	if (opt == IPOPT_EOL)
573	break;
574	if (opt == IPOPT_NOP)
575	len = 1;
576	else {
577	len = cp[IPOPT_OLEN];
578	if (len <= 0 \|\| len > cnt)
579	break;
580	}
581	/*
582	* Should check for overflow, but it "can't happen"
583	*/
584	if (opt == IPOPT_RR \|\| opt == IPOPT_TS \|\|
585	opt == IPOPT_SECURITY) {
586	bcopy((caddr_t)cp,
587	mtod(opts, caddr_t) + opts->m_len, len);
588	opts->m_len += len;
589	}
590	}
591	/* Terminate & pad, if necessary */
592	cnt = opts->m_len % 4;
593	if (cnt) {
594	for (; cnt < 4; cnt++) {
595	*(mtod(opts, caddr_t) + opts->m_len) =
596	IPOPT_EOL;
597	opts->m_len++;
598	}
599	}
600	#ifdef ICMPPRINTFS
601	if (icmpprintfs)
602	printf("%d\n", opts->m_len);
603	#endif
604	}
605	/*
606	* Now strip out original options by copying rest of first
607	* mbuf's data back, and adjust the IP length.
608	*/
609	ip->ip_len -= optlen;
610	ip->ip_vhl = IP_VHL_BORING;
611	m->m_len -= optlen;
612	if (m->m_flags & M_PKTHDR)
613	m->m_pkthdr.len -= optlen;
614	optlen += sizeof(struct ip);
615	bcopy((caddr_t)ip + optlen, (caddr_t)(ip + 1),
616	(unsigned)(m->m_len - sizeof(struct ip)));
617	}
618	m->m_flags &= ~(M_BCAST\|M_MCAST);
619	icmp_send(m, opts);
620	done:
621	if (opts)
622	(void)m_free(opts);
623	}
624
625	/*
626	* Send an icmp packet back to the ip level,
627	* after supplying a checksum.
628	*/
629	static void
630	icmp_send(m, opts)
631	register struct mbuf *m;
632	struct mbuf *opts;
633	{
634	register struct ip ip = mtod(m, struct ip );
635	register int hlen;
636	register struct icmp *icp;
637	struct route ro;
638
639	hlen = IP_VHL_HL(ip->ip_vhl) << 2;
640	m->m_data += hlen;
641	m->m_len -= hlen;
642	icp = mtod(m, struct icmp *);
643	icp->icmp_cksum = 0;
644	icp->icmp_cksum = in_cksum(m, ip->ip_len - hlen);
645	m->m_data -= hlen;
646	m->m_len += hlen;
647	#ifdef ICMPPRINTFS
648	if (icmpprintfs) {
649	char buf[4 * sizeof "123"];
650	strcpy(buf, inet_ntoa(ip->ip_dst));
651	printf("icmp_send dst %s src %s\n",
652	buf, inet_ntoa(ip->ip_src));
653	}
654	#endif
655	bzero(&ro, sizeof ro);
656	(void) ip_output(m, opts, &ro, 0, NULL);
657	if (ro.ro_rt)
658	RTFREE(ro.ro_rt);
659	}
660
661	n_time
662	iptime()
663	{
664	struct timeval atv;
665	u_long t;
666
667	microtime(&atv);
668	t = (atv.tv_sec % (246060)) * 1000 + atv.tv_usec / 1000;
669	return (htonl(t));
670	}
671
672	#if 1
673	/*
674	* Return the next larger or smaller MTU plateau (table from RFC 1191)
675	* given current value MTU. If DIR is less than zero, a larger plateau
676	* is returned; otherwise, a smaller value is returned.
677	*/
678	static int
679	ip_next_mtu(mtu, dir)
680	int mtu;
681	int dir;
682	{
683	static int mtutab[] = {
684	65535, 32000, 17914, 8166, 4352, 2002, 1492, 1006, 508, 296,
685	68, 0
686	};
687	int i;
688
689	for (i = 0; i < (sizeof mtutab) / (sizeof mtutab[0]); i++) {
690	if (mtu >= mtutab[i])
691	break;
692	}
693
694	if (dir < 0) {
695	if (i == 0) {
696	return 0;
697	} else {
698	return mtutab[i - 1];
699	}
700	} else {
701	if (mtutab[i] == 0) {
702	return 0;
703	} else if(mtu > mtutab[i]) {
704	return mtutab[i];
705	} else {
706	return mtutab[i + 1];
707	}
708	}
709	}
710	#endif

Note: See TracBrowser for help on using the repository browser.

Download in other formats: