/* icmp.c ICMP Protocol engine - for sending out pings and receiving responses. */ /* * 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 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 #include #include 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; int 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). */ 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) error ("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) error ("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) error ("attempt to use ICMP protocol before initialization."); to.sin_len = sizeof to; 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 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) warn ("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 sockaddr_in from; u_int8_t icbuf [1500]; int status; int len; 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) { warn ("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 (*) 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); } }