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 */
56 void
icmp4(struct inetgram * igp,struct ip * iphp,uint16_t iphlen,struct in_addr ipsrc)57 icmp4(struct inetgram *igp, struct ip *iphp, uint16_t iphlen,
58 struct 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