1 /* $OpenBSD: icmp.c,v 1.19 2019/10/03 13:36:15 claudio Exp $ */
2
3 /*
4 * Copyright (c) 1997, 1998 The Internet Software Consortium.
5 * All rights reserved.
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 *
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 3. Neither the name of The Internet Software Consortium nor the names
17 * of its contributors may be used to endorse or promote products derived
18 * from this software without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE INTERNET SOFTWARE CONSORTIUM AND
21 * CONTRIBUTORS ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
22 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
23 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
24 * DISCLAIMED. IN NO EVENT SHALL THE INTERNET SOFTWARE CONSORTIUM OR
25 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
26 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
27 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
28 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
29 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
30 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
31 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * SUCH DAMAGE.
33 *
34 * This software has been written for the Internet Software Consortium
35 * by Ted Lemon <mellon@fugue.com> in cooperation with Vixie
36 * Enterprises. To learn more about the Internet Software Consortium,
37 * see ``http://www.vix.com/isc''. To learn more about Vixie
38 * Enterprises, see ``http://www.vix.com''.
39 */
40
41 #include <sys/types.h>
42 #include <sys/socket.h>
43
44 #include <arpa/inet.h>
45
46 #include <net/if.h>
47
48 #include <netinet/ip.h>
49 #include <netinet/ip_icmp.h>
50
51 #include <netdb.h>
52 #include <stdio.h>
53 #include <string.h>
54 #include <unistd.h>
55
56 #include "dhcp.h"
57 #include "tree.h"
58 #include "dhcpd.h"
59 #include "log.h"
60
61 static int icmp_protocol_initialized;
62 static int icmp_protocol_fd;
63
64 /* Initialize the ICMP protocol. */
65
66 void
icmp_startup(int routep,void (* handler)(struct iaddr,u_int8_t *,int))67 icmp_startup(int routep, void (*handler)(struct iaddr, u_int8_t *, int))
68 {
69 struct protoent *proto;
70 int protocol = 1, state;
71
72 /* Only initialize icmp once. */
73 if (icmp_protocol_initialized)
74 fatalx("attempted to reinitialize icmp protocol");
75 icmp_protocol_initialized = 1;
76
77 /* Get the protocol number (should be 1). */
78 if ((proto = getprotobyname("icmp")) != NULL)
79 protocol = proto->p_proto;
80
81 /* Get a raw socket for the ICMP protocol. */
82 if ((icmp_protocol_fd = socket(AF_INET, SOCK_RAW, protocol)) == -1)
83 fatal("unable to create icmp socket");
84
85 /* Make sure it does routing... */
86 state = 0;
87 if (setsockopt(icmp_protocol_fd, SOL_SOCKET, SO_DONTROUTE,
88 &state, sizeof(state)) == -1)
89 fatal("Unable to disable SO_DONTROUTE on ICMP socket");
90
91 add_protocol("icmp", icmp_protocol_fd, icmp_echoreply,
92 (void *)handler);
93 }
94
95 int
icmp_echorequest(struct iaddr * addr)96 icmp_echorequest(struct iaddr *addr)
97 {
98 struct sockaddr_in to;
99 struct icmp icmp;
100 int status;
101
102 if (!icmp_protocol_initialized)
103 fatalx("attempt to use ICMP protocol before initialization.");
104
105 memset(&to, 0, sizeof(to));
106 to.sin_len = sizeof to;
107 to.sin_family = AF_INET;
108 memcpy(&to.sin_addr, addr->iabuf, sizeof to.sin_addr); /* XXX */
109
110 memset(&icmp, 0, sizeof(icmp));
111 icmp.icmp_type = ICMP_ECHO;
112 icmp.icmp_id = getpid() & 0xffff;
113
114 icmp.icmp_cksum = wrapsum(checksum((unsigned char *)&icmp,
115 sizeof(icmp), 0));
116
117 /* Send the ICMP packet... */
118 status = sendto(icmp_protocol_fd, &icmp, sizeof(icmp), 0,
119 (struct sockaddr *)&to, sizeof(to));
120 if (status == -1)
121 log_warn("icmp_echorequest %s", inet_ntoa(to.sin_addr));
122
123 if (status != sizeof icmp)
124 return 0;
125 return 1;
126 }
127
128 void
icmp_echoreply(struct protocol * protocol)129 icmp_echoreply(struct protocol *protocol)
130 {
131 void (*handler)(struct iaddr, u_int8_t *, int);
132 struct sockaddr_in from;
133 u_int8_t icbuf[1500];
134 struct icmp *icfrom;
135 int status, len;
136 socklen_t salen;
137 struct iaddr ia;
138
139 salen = sizeof from;
140 status = recvfrom(protocol->fd, icbuf, sizeof(icbuf), 0,
141 (struct sockaddr *)&from, &salen);
142 if (status == -1) {
143 log_warn("icmp_echoreply");
144 return;
145 }
146
147 /* Probably not for us. */
148 if (status < (sizeof(struct ip)) + (sizeof *icfrom))
149 return;
150
151 len = status - sizeof(struct ip);
152 icfrom = (struct icmp *)(icbuf + sizeof(struct ip));
153
154 /* Silently discard ICMP packets that aren't echoreplies. */
155 if (icfrom->icmp_type != ICMP_ECHOREPLY)
156 return;
157
158 /* If we were given a second-stage handler, call it. */
159 if (protocol->local) {
160 handler = ((void (*)(struct iaddr, u_int8_t *, int))
161 protocol->local);
162 memcpy(ia.iabuf, &from.sin_addr, sizeof from.sin_addr);
163 ia.len = sizeof from.sin_addr;
164 (*handler)(ia, icbuf, len);
165 }
166 }
167