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/* $OpenBSD: icmp.c,v 1.9 2004/09/16 18:35:43 deraadt Exp $ */
/*
* Copyright (c) 1997, 1998 The Internet Software Consortium.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of The Internet Software Consortium nor the names
* of its contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE INTERNET SOFTWARE CONSORTIUM AND
* CONTRIBUTORS ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE INTERNET SOFTWARE CONSORTIUM OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* This software has been written for the Internet Software Consortium
* by Ted Lemon <mellon@fugue.com> in cooperation with Vixie
* Enterprises. To learn more about the Internet Software Consortium,
* see ``http://www.vix.com/isc''. To learn more about Vixie
* Enterprises, see ``http://www.vix.com''.
*/
#include "dhcpd.h"
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#include <netinet/ip_icmp.h>
static int icmp_protocol_initialized;
static int icmp_protocol_fd;
/* Initialize the ICMP protocol. */
void
icmp_startup(int routep, void (*handler)(struct iaddr, u_int8_t *, int))
{
struct protoent *proto;
int protocol = 1, state;
/* Only initialize icmp once. */
if (icmp_protocol_initialized)
error("attempted to reinitialize icmp protocol");
icmp_protocol_initialized = 1;
/* Get the protocol number (should be 1). */
if ((proto = getprotobyname("icmp")) != NULL)
protocol = proto->p_proto;
/* Get a raw socket for the ICMP protocol. */
if ((icmp_protocol_fd = socket(AF_INET, SOCK_RAW, protocol)) == -1)
error("unable to create icmp socket: %m");
/* Make sure it does routing... */
state = 0;
if (setsockopt(icmp_protocol_fd, SOL_SOCKET, SO_DONTROUTE,
&state, sizeof(state)) < 0)
error("Unable to disable SO_DONTROUTE on ICMP socket: %m");
add_protocol("icmp", icmp_protocol_fd, icmp_echoreply, (void *)handler);
}
int
icmp_echorequest(struct iaddr *addr)
{
struct sockaddr_in to;
struct icmp icmp;
int status;
if (!icmp_protocol_initialized)
error("attempt to use ICMP protocol before initialization.");
bzero(&to, sizeof(to));
to.sin_len = sizeof to;
to.sin_family = AF_INET;
memcpy(&to.sin_addr, addr->iabuf, sizeof to.sin_addr); /* XXX */
icmp.icmp_type = ICMP_ECHO;
icmp.icmp_code = 0;
icmp.icmp_cksum = 0;
icmp.icmp_seq = 0;
icmp.icmp_id = getpid() & 0xffff;
icmp.icmp_cksum = wrapsum(checksum((unsigned char *)&icmp,
sizeof(icmp), 0));
/* Send the ICMP packet... */
status = sendto(icmp_protocol_fd, &icmp, sizeof(icmp), 0,
(struct sockaddr *)&to, sizeof(to));
if (status < 0)
warning("icmp_echorequest %s: %m", inet_ntoa(to.sin_addr));
if (status != sizeof icmp)
return 0;
return 1;
}
void
icmp_echoreply(struct protocol *protocol)
{
void (*handler)(struct iaddr, u_int8_t *, int);
struct sockaddr_in from;
u_int8_t icbuf[1500];
struct icmp *icfrom;
int status, len;
socklen_t salen;
struct iaddr ia;
salen = sizeof from;
status = recvfrom(protocol->fd, icbuf, sizeof(icbuf), 0,
(struct sockaddr *)&from, &salen);
if (status < 0) {
warning("icmp_echoreply: %m");
return;
}
/* Probably not for us. */
if (status < (sizeof(struct ip)) + (sizeof *icfrom))
return;
len = status - sizeof(struct ip);
icfrom = (struct icmp *)(icbuf + sizeof(struct ip));
/* Silently discard ICMP packets that aren't echoreplies. */
if (icfrom->icmp_type != ICMP_ECHOREPLY)
return;
/* If we were given a second-stage handler, call it. */
if (protocol->local) {
handler = ((void (*)(struct iaddr, u_int8_t *, int))
protocol->local);
memcpy(ia.iabuf, &from.sin_addr, sizeof from.sin_addr);
ia.len = sizeof from.sin_addr;
(*handler)(ia, icbuf, len);
}
}
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