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/* dhcp.c
ICMP Protocol engine - for sending out pings and receiving
responses. */
/*
* Copyright (c) 1996-1999 Internet Software Consortium.
* Use is subject to license terms which appear in the file named
* ISC-LICENSE that should have accompanied this file when you
* received it. If a file named ISC-LICENSE did not accompany this
* file, or you are not sure the one you have is correct, you may
* obtain an applicable copy of the license at:
*
* http://www.isc.org/isc-license-1.0.html.
*
* This file is part of the ISC DHCP distribution. The documentation
* associated with this file is listed in the file DOCUMENTATION,
* included in the top-level directory of this release.
*
* Support and other services are available for ISC products - see
* http://www.isc.org for more information.
*/
#ifndef lint
static char copyright[] =
"$Id: icmp.c,v 1.13 1999/03/16 05:50:34 mellon Exp $ Copyright (c) 1997, 1998 The Internet Software Consortium. All rights reserved.\n";
#endif /* not lint */
#include "dhcpd.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 (routep, handler)
int routep;
void (*handler) PROTO ((struct iaddr, u_int8_t *, int));
{
struct protoent *proto;
int protocol = 1;
struct sockaddr_in from;
int fd;
int state;
/* Only initialize icmp once. */
if (icmp_protocol_initialized)
log_fatal ("attempted to reinitialize icmp protocol");
icmp_protocol_initialized = 1;
/* Get the protocol number (should be 1). */
proto = getprotobyname ("icmp");
if (proto)
protocol = proto -> p_proto;
/* Get a raw socket for the ICMP protocol. */
icmp_protocol_fd = socket (AF_INET, SOCK_RAW, protocol);
if (icmp_protocol_fd < 0)
log_fatal ("unable to create icmp socket: %m");
/* Make sure it does routing... */
state = 0;
if (setsockopt (icmp_protocol_fd, SOL_SOCKET, SO_DONTROUTE,
(char *)&state, sizeof state) < 0)
log_fatal ("Unable to disable SO_DONTROUTE on ICMP socket: %m");
add_protocol ("icmp", icmp_protocol_fd,
icmp_echoreply, (void *)handler);
}
int icmp_echorequest (addr)
struct iaddr *addr;
{
struct sockaddr_in to;
struct icmp icmp;
int status;
if (!icmp_protocol_initialized)
log_fatal ("attempt to use ICMP protocol before initialization.");
#ifdef HAVE_SA_LEN
to.sin_len = sizeof to;
#endif
to.sin_family = AF_INET;
to.sin_port = 0; /* unused. */
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;
#ifdef PTRSIZE_64BIT
icmp.icmp_id = (((u_int32_t)(u_int64_t)addr) ^
(u_int32_t)(((u_int64_t)addr) >> 32));
#else
icmp.icmp_id = (u_int32_t)addr;
#endif
memset (&icmp.icmp_dun, 0, sizeof icmp.icmp_dun);
icmp.icmp_cksum = wrapsum (checksum ((unsigned char *)&icmp,
sizeof icmp, 0));
/* Send the ICMP packet... */
status = sendto (icmp_protocol_fd, (char *)&icmp, sizeof icmp, 0,
(struct sockaddr *)&to, sizeof to);
if (status < 0)
log_error ("icmp_echorequest %s: %m", inet_ntoa(to.sin_addr));
if (status != sizeof icmp)
return 0;
return 1;
}
void icmp_echoreply (protocol)
struct protocol *protocol;
{
struct icmp *icfrom;
struct ip *ip;
struct sockaddr_in from;
unsigned char icbuf [1500];
int status;
int len, hlen;
struct iaddr ia;
void (*handler) PROTO ((struct iaddr, u_int8_t *, int));
len = sizeof from;
status = recvfrom (protocol -> fd, (char *)icbuf, sizeof icbuf, 0,
(struct sockaddr *)&from, &len);
if (status < 0) {
log_error ("icmp_echoreply: %m");
return;
}
/* Find the IP header length... */
ip = (struct ip *)icbuf;
hlen = ip -> ip_hl << 2;
/* Short packet? */
if (status < hlen + (sizeof *icfrom)) {
return;
}
len = status - hlen;
icfrom = (struct icmp *)(icbuf + hlen);
/* 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 (*) PROTO ((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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