dist/dhcp/common/icmp.c

   1 /* dhcp.c
   2
   3    ICMP Protocol engine - for sending out pings and receiving
   4    responses. */
   5
   6 /*
   7  * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
   8  * Copyright (c) 1996-2003 by Internet Software Consortium
   9  *
  10  * Permission to use, copy, modify, and distribute this software for any
  11  * purpose with or without fee is hereby granted, provided that the above
  12  * copyright notice and this permission notice appear in all copies.
  13  *
  14  * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
  15  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  16  * MERCHANTABILITY AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR
  17  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  18  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  19  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
  20  * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  21  *
  22  *   Internet Systems Consortium, Inc.
  23  *   950 Charter Street
  24  *   Redwood City, CA 94063
  25  *   <info@isc.org>
  26  *   http://www.isc.org/
  27  *
  28  * This software has been written for Internet Systems Consortium
  29  * by Ted Lemon in cooperation with Vixie Enterprises and Nominum, Inc.
  30  * To learn more about Internet Systems Consortium, see
  31  * ``http://www.isc.org/''.  To learn more about Vixie Enterprises,
  32  * see ``http://www.vix.com''.   To learn more about Nominum, Inc., see
  33  * ``http://www.nominum.com''.
  34  */
  35
  36 #ifndef lint
  37 static char copyright[] =
  38 "$Id: icmp.c,v 1.6 2005/08/11 17:13:21 drochner Exp $ Copyright (c) 2004 Internet Systems Consortium.  All rights reserved.\n";
  39 #endif /* not lint */
  40
  41 #include "dhcpd.h"
  42 #include "netinet/ip.h"
  43 #include "netinet/ip_icmp.h"
  44
  45 struct icmp_state *icmp_state;
  46 static omapi_object_type_t *dhcp_type_icmp;
  47 static int no_icmp;
  48
  49 OMAPI_OBJECT_ALLOC (icmp_state, struct icmp_state, dhcp_type_icmp)
  50
  51 #if defined (TRACING)
  52 trace_type_t *trace_icmp_input;
  53 trace_type_t *trace_icmp_output;
  54 #endif
  55
  56 /* Initialize the ICMP protocol. */
  57
  58 void icmp_startup (routep, handler)
  59         int routep;
  60         void (*handler) PROTO ((struct iaddr, u_int8_t *, int));
  61 {
  62         struct protoent *proto;
  63         int protocol = 1;
  64         int state;
  65         isc_result_t result;
  66
  67         /* Only initialize icmp once. */
  68         if (dhcp_type_icmp)
  69                 log_fatal ("attempted to reinitialize icmp protocol");
  70
  71         result = omapi_object_type_register (&dhcp_type_icmp, "icmp",
  72                                              0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
  73                                              sizeof (struct icmp_state),
  74                                              0, RC_MISC);
  75
  76         if (result != ISC_R_SUCCESS)
  77                 log_fatal ("Can't register icmp object type: %s",
  78                            isc_result_totext (result));
  79
  80         icmp_state_allocate (&icmp_state, MDL);
  81         icmp_state -> icmp_handler = handler;
  82
  83 #if defined (TRACING)
  84         trace_icmp_input = trace_type_register ("icmp-input", (void *)0,
  85                                                 trace_icmp_input_input,
  86                                                 trace_icmp_input_stop, MDL);
  87         trace_icmp_output = trace_type_register ("icmp-output", (void *)0,
  88                                                  trace_icmp_output_input,
  89                                                  trace_icmp_output_stop, MDL);
  90
  91         /* If we're playing back a trace file, don't create the socket
  92            or set up the callback. */
  93         if (!trace_playback ()) {
  94 #endif
  95                 /* Get the protocol number (should be 1). */
  96                 proto = getprotobyname ("icmp");
  97                 if (proto)
  98                         protocol = proto -> p_proto;
  99
 100                 /* Get a raw socket for the ICMP protocol. */
 101                 icmp_state -> socket = socket (AF_INET, SOCK_RAW, protocol);
 102                 if (icmp_state -> socket < 0) {
 103                         no_icmp = 1;
 104                         log_error ("unable to create icmp socket: %m");
 105                         return;
 106                 }
 107
 108 #if defined (HAVE_SETFD)
 109                 if (fcntl (icmp_state -> socket, F_SETFD, 1) < 0)
 110                         log_error ("Can't set close-on-exec on icmp: %m");
 111 #endif
 112
 113                 /* Make sure it does routing... */
 114                 state = 0;
 115                 if (setsockopt (icmp_state -> socket, SOL_SOCKET, SO_DONTROUTE,
 116                                 (char *)&state, sizeof state) < 0)
 117                         log_fatal ("Can't disable SO_DONTROUTE on ICMP: %m");
 118
 119                 result = (omapi_register_io_object
 120                           ((omapi_object_t *)icmp_state,
 121                            icmp_readsocket, 0, icmp_echoreply, 0, 0));
 122                 if (result != ISC_R_SUCCESS)
 123                         log_fatal ("Can't register icmp handle: %s",
 124                                    isc_result_totext (result));
 125 #if defined (TRACING)
 126         }
 127 #endif
 128 }
 129
 130 int icmp_readsocket (h)
 131         omapi_object_t *h;
 132 {
 133         struct icmp_state *state;
 134
 135         state = (struct icmp_state *)h;
 136         return state -> socket;
 137 }
 138
 139 int icmp_echorequest (addr)
 140         struct iaddr *addr;
 141 {
 142         struct sockaddr_in to;
 143         struct icmp icmp;
 144         int status;
 145 #if defined (TRACING)
 146         trace_iov_t iov [2];
 147 #endif
 148
 149         if (no_icmp)
 150                 return 1;
 151         if (!icmp_state)
 152                 log_fatal ("ICMP protocol used before initialization.");
 153
 154         memset (&to, 0, sizeof(to));
 155 #ifdef HAVE_SA_LEN
 156         to.sin_len = sizeof to;
 157 #endif
 158         to.sin_family = AF_INET;
 159         to.sin_port = 0; /* unused. */
 160         memcpy (&to.sin_addr, addr -> iabuf, sizeof to.sin_addr); /* XXX */
 161
 162         icmp.icmp_type = ICMP_ECHO;
 163         icmp.icmp_code = 0;
 164         icmp.icmp_cksum = 0;
 165         icmp.icmp_seq = 0;
 166 #ifdef PTRSIZE_64BIT
 167         icmp.icmp_id = (((u_int32_t)(u_int64_t)addr) ^
 168                         (u_int32_t)(((u_int64_t)addr) >> 32));
 169 #else
 170         icmp.icmp_id = (u_int32_t)addr;
 171 #endif
 172         memset (&icmp.icmp_dun, 0, sizeof icmp.icmp_dun);
 173
 174         icmp.icmp_cksum = wrapsum (checksum ((unsigned char *)&icmp,
 175                                              sizeof icmp, 0));
 176
 177 #if defined (TRACING)
 178         if (trace_playback ()) {
 179                 char *buf = (char *)0;
 180                 unsigned buflen = 0;
 181
 182                 /* Consume the ICMP event. */
 183                 status = trace_get_packet (&trace_icmp_output, &buflen, &buf);
 184                 if (status != ISC_R_SUCCESS)
 185                         log_error ("icmp_echorequest: %s",
 186                                    isc_result_totext (status));
 187                 if (buf)
 188                         dfree (buf, MDL);
 189         } else {
 190                 if (trace_record ()) {
 191                         iov [0].buf = (char *)addr;
 192                         iov [0].len = sizeof *addr;
 193                         iov [1].buf = (char *)&icmp;
 194                         iov [1].len = sizeof icmp;
 195                         trace_write_packet_iov (trace_icmp_output,
 196                                                 2, iov, MDL);
 197                 }
 198 #endif
 199                 /* Send the ICMP packet... */
 200                 status = sendto (icmp_state -> socket,
 201                                  (char *)&icmp, sizeof icmp, 0,
 202                                  (struct sockaddr *)&to, sizeof to);
 203                 if (status < 0)
 204                         log_error ("icmp_echorequest %s: %m",
 205                                    inet_ntoa(to.sin_addr));
 206
 207                 if (status != sizeof icmp)
 208                         return 0;
 209 #if defined (TRACING)
 210         }
 211 #endif
 212         return 1;
 213 }
 214
 215 isc_result_t icmp_echoreply (h)
 216         omapi_object_t *h;
 217 {
 218         struct icmp *icfrom;
 219         struct ip *ip;
 220         struct sockaddr_in from;
 221         u_int8_t icbuf [1500];
 222         int status;
 223         SOCKLEN_T sl;
 224         int hlen, len;
 225         struct iaddr ia;
 226         struct icmp_state *state;
 227 #if defined (TRACING)
 228         trace_iov_t iov [2];
 229 #endif
 230
 231         state = (struct icmp_state *)h;
 232
 233         sl = sizeof from;
 234         status = recvfrom (state -> socket, (char *)icbuf, sizeof icbuf, 0,
 235                           (struct sockaddr *)&from, &sl);
 236         if (status < 0) {
 237                 log_error ("icmp_echoreply: %m");
 238                 return ISC_R_UNEXPECTED;
 239         }
 240
 241         /* Find the IP header length... */
 242         ip = (struct ip *)icbuf;
 243         hlen = IP_HL (ip);
 244
 245         /* Short packet? */
 246         if (status < hlen + (sizeof *icfrom)) {
 247                 return ISC_R_SUCCESS;
 248         }
 249
 250         len = status - hlen;
 251         icfrom = (struct icmp *)(icbuf + hlen);
 252
 253         /* Silently discard ICMP packets that aren't echoreplies. */
 254         if (icfrom -> icmp_type != ICMP_ECHOREPLY) {
 255                 return ISC_R_SUCCESS;
 256         }
 257
 258         /* If we were given a second-stage handler, call it. */
 259         if (state -> icmp_handler) {
 260                 memcpy (ia.iabuf, &from.sin_addr, sizeof from.sin_addr);
 261                 ia.len = sizeof from.sin_addr;
 262
 263 #if defined (TRACING)
 264                 if (trace_record ()) {
 265                         ia.len = htonl(ia.len);
 266                         iov [0].buf = (char *)&ia;
 267                         iov [0].len = sizeof ia;
 268                         iov [1].buf = (char *)icbuf;
 269                         iov [1].len = len;
 270                         trace_write_packet_iov (trace_icmp_input, 2, iov, MDL);
 271                         ia.len = ntohl(ia.len);
 272                 }
 273 #endif
 274                 (*state -> icmp_handler) (ia, icbuf, len);
 275         }
 276         return ISC_R_SUCCESS;
 277 }
 278
 279 #if defined (TRACING)
 280 void trace_icmp_input_input (trace_type_t *ttype, unsigned length, char *buf)
 281 {
 282         struct iaddr *ia;
 283         u_int8_t *icbuf;
 284         ia = (struct iaddr *)buf;
 285         ia->len = ntohl(ia->len);
 286         icbuf = (u_int8_t *)(ia + 1);
 287         if (icmp_state -> icmp_handler)
 288                 (*icmp_state -> icmp_handler) (*ia, icbuf,
 289                                                (int)(length - sizeof ia));
 290 }
 291
 292 void trace_icmp_input_stop (trace_type_t *ttype) { }
 293
 294 void trace_icmp_output_input (trace_type_t *ttype, unsigned length, char *buf)
 295 {
 296         struct icmp *icmp;
 297         struct iaddr ia;
 298
 299         if (length != (sizeof (*icmp) + (sizeof ia))) {
 300                 log_error ("trace_icmp_output_input: data size mismatch %d:%d",
 301                            length, (int)((sizeof (*icmp)) + (sizeof ia)));
 302                 return;
 303         }
 304         ia.len = 4;
 305         memcpy (ia.iabuf, buf, 4);
 306         icmp = (struct icmp *)(buf + 1);
 307
 308         log_error ("trace_icmp_output_input: unsent ping to %s", piaddr (ia));
 309 }
 310
 311 void trace_icmp_output_stop (trace_type_t *ttype) { }
 312 #endif /* TRACING */