1/*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License, Version 1.0 only
6 * (the "License").  You may not use this file except in compliance
7 * with the License.
8 *
9 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10 * or http://www.opensolaris.org/os/licensing.
11 * See the License for the specific language governing permissions
12 * and limitations under the License.
13 *
14 * When distributing Covered Code, include this CDDL HEADER in each
15 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16 * If applicable, add the following below this CDDL HEADER, with the
17 * fields enclosed by brackets "[]" replaced with your own identifying
18 * information: Portions Copyright [yyyy] [name of copyright owner]
19 *
20 * CDDL HEADER END
21 */
22/*
23 * Copyright 1991-2003 Sun Microsystems, Inc.  All rights reserved.
24 * Use is subject to license terms.
25 *
26 * icmp4.c, Code implementing the Internet Control Message Protocol (v4) ICMP.
27 */
28
29#pragma ident	"%Z%%M%	%I%	%E% SMI"
30
31#include <sys/types.h>
32#include <socket_impl.h>
33#include <socket_inet.h>
34#include <sys/salib.h>
35#include <sys/socket.h>
36#include <netinet/in_systm.h>
37#include <netinet/in.h>
38#include <netinet/ip.h>
39#include <netinet/udp.h>
40#include <netinet/ip_icmp.h>
41#include <sys/bootconf.h>
42#include <sys/fcntl.h>
43
44#include "icmp4.h"
45#include "ipv4.h"
46#include "ipv4_impl.h"
47#include "mac.h"
48#include "v4_sum_impl.h"
49#include <sys/bootdebug.h>
50
51/*
52 * Handle ICMP redirects, ICMP echo messages. We only deal with redirects to a
53 * different default router by changing the default route to the specified
54 * value.
55 */
56void
57icmp4(struct inetgram *igp, struct ip *iphp, uint16_t iphlen,
58struct in_addr ipsrc)
59{
60	int		icmp_len;
61	struct in_addr	our_ip;
62	struct icmp	*icmphp;
63
64	icmp_len = ntohs(iphp->ip_len) - iphlen;
65	if (icmp_len < ICMP_MINLEN) {
66#ifdef	DEBUG
67		printf("icmp4: ICMP message from %s is too short\n",
68		    inet_ntoa(ipsrc));
69#endif	/* DEBUG */
70		return;
71	}
72
73	icmphp = (struct icmp *)(igp->igm_mp->b_rptr + iphlen);
74
75	/* check alignment */
76	if ((uintptr_t)icmphp % sizeof (uint16_t)) {
77		dprintf("icmp4: ICMP header not aligned (from %s)\n",
78		    inet_ntoa(ipsrc));
79		return;
80	}
81	if (ipv4cksum((uint16_t *)icmphp, icmp_len) != 0) {
82		dprintf("icmp4: Bad ICMP checksum (from %s)\n",
83		    inet_ntoa(ipsrc));
84		return;
85	}
86	switch (icmphp->icmp_type) {
87	case ICMP_REDIRECT:
88		if (icmphp->icmp_code != ICMP_REDIRECT_HOST)
89			break;
90		dprintf("ICMP Redirect to gateway %s.\n",
91		    inet_ntoa(icmphp->icmp_gwaddr));
92		if (ipv4_route(IPV4_ADD_ROUTE, RT_HOST, &icmphp->icmp_ip.ip_dst,
93		    &icmphp->icmp_gwaddr) != 0) {
94			dprintf("icmp4: Cannot add route %s, %d\n",
95			    inet_ntoa(icmphp->icmp_ip.ip_dst), errno);
96		}
97		break;
98	case ICMP_UNREACH:
99		/*
100		 * Need to highlight an error on the socket, and save the
101		 * destination address so that we can ensure it is destined
102		 * to this socket. We need the port number to be sure...
103		 */
104		dprintf("ICMP destination unreachable (%s)\n",
105		    inet_ntoa(icmphp->icmp_ip.ip_dst));
106		break;
107	case ICMP_ECHO:
108		/*
109		 * swap the source and destination IP addresses
110		 * and send a reply right out.
111		 */
112		ipv4_getipaddr(&our_ip);
113		if (our_ip.s_addr != INADDR_ANY) {
114			int			s;
115			struct sockaddr_in	dest;
116
117			if ((s = socket(AF_INET, SOCK_RAW, IPPROTO_ICMP)) < 0) {
118				dprintf("icmp4: socket: %d\n", errno);
119				break;
120			}
121			icmphp->icmp_type = ICMP_ECHOREPLY;
122			icmphp->icmp_cksum = 0;
123			icmphp->icmp_cksum = ipv4cksum((uint16_t *)icmphp,
124			    icmp_len);
125			dest.sin_family = AF_INET;
126			dest.sin_addr.s_addr = ipsrc.s_addr;
127			dest.sin_port = htons(0);
128			(void) sendto(s, (caddr_t)icmphp, icmp_len, 0,
129			    (const struct sockaddr *)&dest, sizeof (dest));
130			(void) socket_close(s);
131		}
132		break;
133	default:
134		dprintf("icmp4: Unsupported ICMP message type: 0x%x "
135		    "received from %s\n", icmphp->icmp_type, inet_ntoa(ipsrc));
136		break;
137	}
138}
139