contrib/dhcp-3.0/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 1.30.2.6 2004/06/10 17:59:18 dhankins 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         struct sockaddr_in from;
  65         int fd;
  66         int state;
  67         struct icmp_state *new;
  68         omapi_object_t *h;
  69         isc_result_t result;
  70
  71         /* Only initialize icmp once. */
  72         if (dhcp_type_icmp)
  73                 log_fatal ("attempted to reinitialize icmp protocol");
  74
  75         result = omapi_object_type_register (&dhcp_type_icmp, "icmp",
  76                                              0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
  77                                              sizeof (struct icmp_state),
  78                                              0, RC_MISC);
  79
  80         if (result != ISC_R_SUCCESS)
  81                 log_fatal ("Can't register icmp object type: %s",
  82                            isc_result_totext (result));
  83
  84         icmp_state_allocate (&icmp_state, MDL);
  85         icmp_state -> icmp_handler = handler;
  86
  87 #if defined (TRACING)
  88         trace_icmp_input = trace_type_register ("icmp-input", (void *)0,
  89                                                 trace_icmp_input_input,
  90                                                 trace_icmp_input_stop, MDL);
  91         trace_icmp_output = trace_type_register ("icmp-output", (void *)0,
  92                                                  trace_icmp_output_input,
  93                                                  trace_icmp_output_stop, MDL);
  94
  95         /* If we're playing back a trace file, don't create the socket
  96            or set up the callback. */
  97         if (!trace_playback ()) {
  98 #endif
  99                 /* Get the protocol number (should be 1). */
 100                 proto = getprotobyname ("icmp");
 101                 if (proto)
 102                         protocol = proto -> p_proto;
 103
 104                 /* Get a raw socket for the ICMP protocol. */
 105                 icmp_state -> socket = socket (AF_INET, SOCK_RAW, protocol);
 106                 if (icmp_state -> socket < 0) {
 107                         no_icmp = 1;
 108                         log_error ("unable to create icmp socket: %m");
 109                         return;
 110                 }
 111
 112 #if defined (HAVE_SETFD)
 113                 if (fcntl (icmp_state -> socket, F_SETFD, 1) < 0)
 114                         log_error ("Can't set close-on-exec on icmp: %m");
 115 #endif
 116
 117                 /* Make sure it does routing... */
 118                 state = 0;
 119                 if (setsockopt (icmp_state -> socket, SOL_SOCKET, SO_DONTROUTE,
 120                                 (char *)&state, sizeof state) < 0)
 121                         log_fatal ("Can't disable SO_DONTROUTE on ICMP: %m");
 122
 123                 result = (omapi_register_io_object
 124                           ((omapi_object_t *)icmp_state,
 125                            icmp_readsocket, 0, icmp_echoreply, 0, 0));
 126                 if (result != ISC_R_SUCCESS)
 127                         log_fatal ("Can't register icmp handle: %s",
 128                                    isc_result_totext (result));
 129 #if defined (TRACING)
 130         }
 131 #endif
 132 }
 133
 134 int icmp_readsocket (h)
 135         omapi_object_t *h;
 136 {
 137         struct icmp_state *state;
 138
 139         state = (struct icmp_state *)h;
 140         return state -> socket;
 141 }
 142
 143 int icmp_echorequest (addr)
 144         struct iaddr *addr;
 145 {
 146         struct sockaddr_in to;
 147         struct icmp icmp;
 148         int status;
 149 #if defined (TRACING)
 150         trace_iov_t iov [2];
 151 #endif
 152
 153         if (no_icmp)
 154                 return 1;
 155         if (!icmp_state)
 156                 log_fatal ("ICMP protocol used before initialization.");
 157
 158         memset (&to, 0, sizeof(to));
 159 #ifdef HAVE_SA_LEN
 160         to.sin_len = sizeof to;
 161 #endif
 162         to.sin_family = AF_INET;
 163         to.sin_port = 0; /* unused. */
 164         memcpy (&to.sin_addr, addr -> iabuf, sizeof to.sin_addr); /* XXX */
 165
 166         icmp.icmp_type = ICMP_ECHO;
 167         icmp.icmp_code = 0;
 168         icmp.icmp_cksum = 0;
 169         icmp.icmp_seq = 0;
 170 #ifdef PTRSIZE_64BIT
 171         icmp.icmp_id = (((u_int32_t)(u_int64_t)addr) ^
 172                         (u_int32_t)(((u_int64_t)addr) >> 32));
 173 #else
 174         icmp.icmp_id = (u_int32_t)addr;
 175 #endif
 176         memset (&icmp.icmp_dun, 0, sizeof icmp.icmp_dun);
 177
 178         icmp.icmp_cksum = wrapsum (checksum ((unsigned char *)&icmp,
 179                                              sizeof icmp, 0));
 180
 181 #if defined (TRACING)
 182         if (trace_playback ()) {
 183                 char *buf = (char *)0;
 184                 unsigned buflen = 0;
 185
 186                 /* Consume the ICMP event. */
 187                 status = trace_get_packet (&trace_icmp_output, &buflen, &buf);
 188                 if (status != ISC_R_SUCCESS)
 189                         log_error ("icmp_echorequest: %s",
 190                                    isc_result_totext (status));
 191                 if (buf)
 192                         dfree (buf, MDL);
 193         } else {
 194                 if (trace_record ()) {
 195                         iov [0].buf = (char *)addr;
 196                         iov [0].len = sizeof *addr;
 197                         iov [1].buf = (char *)&icmp;
 198                         iov [1].len = sizeof icmp;
 199                         trace_write_packet_iov (trace_icmp_output,
 200                                                 2, iov, MDL);
 201                 }
 202 #endif
 203                 /* Send the ICMP packet... */
 204                 status = sendto (icmp_state -> socket,
 205                                  (char *)&icmp, sizeof icmp, 0,
 206                                  (struct sockaddr *)&to, sizeof to);
 207                 if (status < 0)
 208                         log_error ("icmp_echorequest %s: %m",
 209                                    inet_ntoa(to.sin_addr));
 210
 211                 if (status != sizeof icmp)
 212                         return 0;
 213 #if defined (TRACING)
 214         }
 215 #endif
 216         return 1;
 217 }
 218
 219 isc_result_t icmp_echoreply (h)
 220         omapi_object_t *h;
 221 {
 222         struct icmp *icfrom;
 223         struct ip *ip;
 224         struct sockaddr_in from;
 225         u_int8_t icbuf [1500];
 226         int status;
 227         SOCKLEN_T sl;
 228         int hlen, len;
 229         struct iaddr ia;
 230         struct icmp_state *state;
 231 #if defined (TRACING)
 232         trace_iov_t iov [2];
 233 #endif
 234
 235         state = (struct icmp_state *)h;
 236
 237         sl = sizeof from;
 238         status = recvfrom (state -> socket, (char *)icbuf, sizeof icbuf, 0,
 239                           (struct sockaddr *)&from, &sl);
 240         if (status < 0) {
 241                 log_error ("icmp_echoreply: %m");
 242                 return ISC_R_UNEXPECTED;
 243         }
 244
 245         /* Find the IP header length... */
 246         ip = (struct ip *)icbuf;
 247         hlen = IP_HL (ip);
 248
 249         /* Short packet? */
 250         if (status < hlen + (sizeof *icfrom)) {
 251                 return ISC_R_SUCCESS;
 252         }
 253
 254         len = status - hlen;
 255         icfrom = (struct icmp *)(icbuf + hlen);
 256
 257         /* Silently discard ICMP packets that aren't echoreplies. */
 258         if (icfrom -> icmp_type != ICMP_ECHOREPLY) {
 259                 return ISC_R_SUCCESS;
 260         }
 261
 262         /* If we were given a second-stage handler, call it. */
 263         if (state -> icmp_handler) {
 264                 memcpy (ia.iabuf, &from.sin_addr, sizeof from.sin_addr);
 265                 ia.len = sizeof from.sin_addr;
 266
 267 #if defined (TRACING)
 268                 if (trace_record ()) {
 269                         ia.len = htonl(ia.len);
 270                         iov [0].buf = (char *)&ia;
 271                         iov [0].len = sizeof ia;
 272                         iov [1].buf = (char *)icbuf;
 273                         iov [1].len = len;
 274                         trace_write_packet_iov (trace_icmp_input, 2, iov, MDL);
 275                         ia.len = ntohl(ia.len);
 276                 }
 277 #endif
 278                 (*state -> icmp_handler) (ia, icbuf, len);
 279         }
 280         return ISC_R_SUCCESS;
 281 }
 282
 283 #if defined (TRACING)
 284 void trace_icmp_input_input (trace_type_t *ttype, unsigned length, char *buf)
 285 {
 286         struct iaddr *ia;
 287         unsigned len;
 288         u_int8_t *icbuf;
 289         ia = (struct iaddr *)buf;
 290         ia->len = ntohl(ia->len);
 291         icbuf = (u_int8_t *)(ia + 1);
 292         if (icmp_state -> icmp_handler)
 293                 (*icmp_state -> icmp_handler) (*ia, icbuf,
 294                                                (int)(length - sizeof ia));
 295 }
 296
 297 void trace_icmp_input_stop (trace_type_t *ttype) { }
 298
 299 void trace_icmp_output_input (trace_type_t *ttype, unsigned length, char *buf)
 300 {
 301         struct icmp *icmp;
 302         struct iaddr ia;
 303
 304         if (length != (sizeof (*icmp) + (sizeof ia))) {
 305                 log_error ("trace_icmp_output_input: data size mismatch %d:%d",
 306                            length, (int)((sizeof (*icmp)) + (sizeof ia)));
 307                 return;
 308         }
 309         ia.len = 4;
 310         memcpy (ia.iabuf, buf, 4);
 311         icmp = (struct icmp *)(buf + 1);
 312
 313         log_error ("trace_icmp_output_input: unsent ping to %s", piaddr (ia));
 314 }
 315
 316 void trace_icmp_output_stop (trace_type_t *ttype) { }
 317 #endif /* TRACING */