1 |
|
|
/* $OpenBSD: icmp.c,v 1.18 2017/02/13 23:04:05 krw 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 |
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 |
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 |
|
|
icmp.icmp_type = ICMP_ECHO; |
111 |
|
|
icmp.icmp_code = 0; |
112 |
|
|
icmp.icmp_cksum = 0; |
113 |
|
|
icmp.icmp_seq = 0; |
114 |
|
|
icmp.icmp_id = getpid() & 0xffff; |
115 |
|
|
|
116 |
|
|
icmp.icmp_cksum = wrapsum(checksum((unsigned char *)&icmp, |
117 |
|
|
sizeof(icmp), 0)); |
118 |
|
|
|
119 |
|
|
/* Send the ICMP packet... */ |
120 |
|
|
status = sendto(icmp_protocol_fd, &icmp, sizeof(icmp), 0, |
121 |
|
|
(struct sockaddr *)&to, sizeof(to)); |
122 |
|
|
if (status == -1) |
123 |
|
|
log_warn("icmp_echorequest %s", inet_ntoa(to.sin_addr)); |
124 |
|
|
|
125 |
|
|
if (status != sizeof icmp) |
126 |
|
|
return 0; |
127 |
|
|
return 1; |
128 |
|
|
} |
129 |
|
|
|
130 |
|
|
void |
131 |
|
|
icmp_echoreply(struct protocol *protocol) |
132 |
|
|
{ |
133 |
|
|
void (*handler)(struct iaddr, u_int8_t *, int); |
134 |
|
|
struct sockaddr_in from; |
135 |
|
|
u_int8_t icbuf[1500]; |
136 |
|
|
struct icmp *icfrom; |
137 |
|
|
int status, len; |
138 |
|
|
socklen_t salen; |
139 |
|
|
struct iaddr ia; |
140 |
|
|
|
141 |
|
|
salen = sizeof from; |
142 |
|
|
status = recvfrom(protocol->fd, icbuf, sizeof(icbuf), 0, |
143 |
|
|
(struct sockaddr *)&from, &salen); |
144 |
|
|
if (status == -1) { |
145 |
|
|
log_warn("icmp_echoreply"); |
146 |
|
|
return; |
147 |
|
|
} |
148 |
|
|
|
149 |
|
|
/* Probably not for us. */ |
150 |
|
|
if (status < (sizeof(struct ip)) + (sizeof *icfrom)) |
151 |
|
|
return; |
152 |
|
|
|
153 |
|
|
len = status - sizeof(struct ip); |
154 |
|
|
icfrom = (struct icmp *)(icbuf + sizeof(struct ip)); |
155 |
|
|
|
156 |
|
|
/* Silently discard ICMP packets that aren't echoreplies. */ |
157 |
|
|
if (icfrom->icmp_type != ICMP_ECHOREPLY) |
158 |
|
|
return; |
159 |
|
|
|
160 |
|
|
/* If we were given a second-stage handler, call it. */ |
161 |
|
|
if (protocol->local) { |
162 |
|
|
handler = ((void (*)(struct iaddr, u_int8_t *, int)) |
163 |
|
|
protocol->local); |
164 |
|
|
memcpy(ia.iabuf, &from.sin_addr, sizeof from.sin_addr); |
165 |
|
|
ia.len = sizeof from.sin_addr; |
166 |
|
|
(*handler)(ia, icbuf, len); |
167 |
|
|
} |
168 |
|
|
} |