common/icmp.c

   1 /* dhcp.c
   2
   3    ICMP Protocol engine - for sending out pings and receiving
   4    responses. */
   5
   6 /*
   7  * Copyright (c) 2004-2017 by Internet Systems Consortium, Inc. ("ISC")
   8  * Copyright (c) 1996-2003 by Internet Software Consortium
   9  *
  10  * This Source Code Form is subject to the terms of the Mozilla Public
  11  * License, v. 2.0. If a copy of the MPL was not distributed with this
  12  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
  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  *   PO Box 360
  24  *   Newmarket, NH 03857 USA
  25  *   <info@isc.org>
  26  *   https://www.isc.org/
  27  *
  28  */
  29
  30 #include "dhcpd.h"
  31 #include "netinet/ip.h"
  32 #include "netinet/ip_icmp.h"
  33
  34 struct icmp_state *icmp_state;
  35 static omapi_object_type_t *dhcp_type_icmp;
  36 static int no_icmp;
  37
  38 OMAPI_OBJECT_ALLOC (icmp_state, struct icmp_state, dhcp_type_icmp)
  39
  40 #if defined (TRACING)
  41 trace_type_t *trace_icmp_input;
  42 trace_type_t *trace_icmp_output;
  43 #endif
  44
  45 /* Initialize the ICMP protocol. */
  46
  47 void icmp_startup (routep, handler)
  48         int routep;
  49         void (*handler) (struct iaddr, u_int8_t *, int);
  50 {
  51         struct protoent *proto;
  52         int protocol = 1;
  53         int state;
  54         isc_result_t result;
  55
  56         /* Only initialize icmp once. */
  57         if (dhcp_type_icmp)
  58                 log_fatal ("attempted to reinitialize icmp protocol");
  59
  60         result = omapi_object_type_register (&dhcp_type_icmp, "icmp",
  61                                              0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
  62                                              sizeof (struct icmp_state),
  63                                              0, RC_MISC);
  64
  65         if (result != ISC_R_SUCCESS)
  66                 log_fatal ("Can't register icmp object type: %s",
  67                            isc_result_totext (result));
  68
  69         icmp_state_allocate (&icmp_state, MDL);
  70         icmp_state -> icmp_handler = handler;
  71
  72 #if defined (TRACING)
  73         trace_icmp_input = trace_type_register ("icmp-input", (void *)0,
  74                                                 trace_icmp_input_input,
  75                                                 trace_icmp_input_stop, MDL);
  76         trace_icmp_output = trace_type_register ("icmp-output", (void *)0,
  77                                                  trace_icmp_output_input,
  78                                                  trace_icmp_output_stop, MDL);
  79
  80         /* If we're playing back a trace file, don't create the socket
  81            or set up the callback. */
  82         if (!trace_playback ()) {
  83 #endif
  84                 /* Get the protocol number (should be 1). */
  85                 proto = getprotobyname ("icmp");
  86                 if (proto)
  87                         protocol = proto -> p_proto;
  88
  89                 /* Get a raw socket for the ICMP protocol. */
  90                 icmp_state -> socket = socket (AF_INET, SOCK_RAW, protocol);
  91                 if (icmp_state -> socket < 0) {
  92                         no_icmp = 1;
  93                         log_error ("unable to create icmp socket: %m");
  94                         return;
  95                 }
  96
  97 #if defined (HAVE_SETFD)
  98                 if (fcntl (icmp_state -> socket, F_SETFD, 1) < 0)
  99                         log_error ("Can't set close-on-exec on icmp: %m");
 100 #endif
 101
 102                 /* Make sure it does routing... */
 103                 state = 0;
 104                 if (setsockopt (icmp_state -> socket, SOL_SOCKET, SO_DONTROUTE,
 105                                 (char *)&state, sizeof state) < 0)
 106                         log_fatal ("Can't disable SO_DONTROUTE on ICMP: %m");
 107
 108                 result = (omapi_register_io_object
 109                           ((omapi_object_t *)icmp_state,
 110                            icmp_readsocket, 0, icmp_echoreply, 0, 0));
 111                 if (result != ISC_R_SUCCESS)
 112                         log_fatal ("Can't register icmp handle: %s",
 113                                    isc_result_totext (result));
 114 #if defined (TRACING)
 115         }
 116 #endif
 117 }
 118
 119 int icmp_readsocket (h)
 120         omapi_object_t *h;
 121 {
 122         struct icmp_state *state;
 123
 124         state = (struct icmp_state *)h;
 125         return state -> socket;
 126 }
 127
 128 int icmp_echorequest (addr)
 129         struct iaddr *addr;
 130 {
 131         struct sockaddr_in to;
 132         struct icmp icmp;
 133         int status;
 134 #if defined (TRACING)
 135         trace_iov_t iov [2];
 136 #endif
 137
 138         if (no_icmp)
 139                 return 1;
 140         if (!icmp_state)
 141                 log_fatal ("ICMP protocol used before initialization.");
 142
 143         memset (&to, 0, sizeof(to));
 144 #ifdef HAVE_SA_LEN
 145         to.sin_len = sizeof to;
 146 #endif
 147         to.sin_family = AF_INET;
 148         to.sin_port = 0; /* unused. */
 149         memcpy (&to.sin_addr, addr -> iabuf, sizeof to.sin_addr); /* XXX */
 150
 151         icmp.icmp_type = ICMP_ECHO;
 152         icmp.icmp_code = 0;
 153         icmp.icmp_cksum = 0;
 154         icmp.icmp_seq = 0;
 155 #if SIZEOF_STRUCT_IADDR_P == 8
 156         icmp.icmp_id = (((u_int32_t)(u_int64_t)addr) ^
 157                         (u_int32_t)(((u_int64_t)addr) >> 32));
 158 #else
 159         icmp.icmp_id = (u_int32_t)addr;
 160 #endif
 161         memset (&icmp.icmp_dun, 0, sizeof icmp.icmp_dun);
 162
 163         icmp.icmp_cksum = wrapsum (checksum ((unsigned char *)&icmp,
 164                                              sizeof icmp, 0));
 165
 166 #if defined (TRACING)
 167         if (trace_playback ()) {
 168                 char *buf = (char *)0;
 169                 unsigned buflen = 0;
 170
 171                 /* Consume the ICMP event. */
 172                 status = trace_get_packet (&trace_icmp_output, &buflen, &buf);
 173                 if (status != ISC_R_SUCCESS)
 174                         log_error ("icmp_echorequest: %s",
 175                                    isc_result_totext (status));
 176                 if (buf)
 177                         dfree (buf, MDL);
 178         } else {
 179                 if (trace_record ()) {
 180                         iov [0].buf = (char *)addr;
 181                         iov [0].len = sizeof *addr;
 182                         iov [1].buf = (char *)&icmp;
 183                         iov [1].len = sizeof icmp;
 184                         trace_write_packet_iov (trace_icmp_output,
 185                                                 2, iov, MDL);
 186                 }
 187 #endif
 188                 /* Send the ICMP packet... */
 189                 status = sendto (icmp_state -> socket,
 190                                  (char *)&icmp, sizeof icmp, 0,
 191                                  (struct sockaddr *)&to, sizeof to);
 192                 if (status < 0)
 193                         log_error ("icmp_echorequest %s: %m",
 194                                    inet_ntoa(to.sin_addr));
 195
 196                 if (status != sizeof icmp)
 197                         return 0;
 198 #if defined (TRACING)
 199         }
 200 #endif
 201         return 1;
 202 }
 203
 204 isc_result_t icmp_echoreply (h)
 205         omapi_object_t *h;
 206 {
 207         struct icmp *icfrom;
 208         struct ip *ip;
 209         struct sockaddr_in from;
 210         u_int8_t icbuf [1500];
 211         int status;
 212         SOCKLEN_T sl;
 213         int hlen, len;
 214         struct iaddr ia;
 215         struct icmp_state *state;
 216 #if defined (TRACING)
 217         trace_iov_t iov [2];
 218 #endif
 219
 220         state = (struct icmp_state *)h;
 221
 222         sl = sizeof from;
 223         status = recvfrom (state -> socket, (char *)icbuf, sizeof icbuf, 0,
 224                           (struct sockaddr *)&from, &sl);
 225         if (status < 0) {
 226                 log_error ("icmp_echoreply: %m");
 227                 return ISC_R_UNEXPECTED;
 228         }
 229
 230         /* Find the IP header length... */
 231         ip = (struct ip *)icbuf;
 232         hlen = IP_HL (ip);
 233
 234         /* Short packet? */
 235         if (status < hlen + (sizeof *icfrom)) {
 236                 return ISC_R_SUCCESS;
 237         }
 238
 239         len = status - hlen;
 240         icfrom = (struct icmp *)(icbuf + hlen);
 241
 242         /* Silently discard ICMP packets that aren't echoreplies. */
 243         if (icfrom -> icmp_type != ICMP_ECHOREPLY) {
 244                 return ISC_R_SUCCESS;
 245         }
 246
 247         /* If we were given a second-stage handler, call it. */
 248         if (state -> icmp_handler) {
 249                 memcpy (ia.iabuf, &from.sin_addr, sizeof from.sin_addr);
 250                 ia.len = sizeof from.sin_addr;
 251
 252 #if defined (TRACING)
 253                 if (trace_record ()) {
 254                         ia.len = htonl(ia.len);
 255                         iov [0].buf = (char *)&ia;
 256                         iov [0].len = sizeof ia;
 257                         iov [1].buf = (char *)icbuf;
 258                         iov [1].len = len;
 259                         trace_write_packet_iov (trace_icmp_input, 2, iov, MDL);
 260                         ia.len = ntohl(ia.len);
 261                 }
 262 #endif
 263                 (*state -> icmp_handler) (ia, icbuf, len);
 264         }
 265         return ISC_R_SUCCESS;
 266 }
 267
 268 #if defined (TRACING)
 269 void trace_icmp_input_input (trace_type_t *ttype, unsigned length, char *buf)
 270 {
 271         struct iaddr *ia;
 272         u_int8_t *icbuf;
 273         ia = (struct iaddr *)buf;
 274         ia->len = ntohl(ia->len);
 275         icbuf = (u_int8_t *)(ia + 1);
 276         if (icmp_state -> icmp_handler)
 277                 (*icmp_state -> icmp_handler) (*ia, icbuf,
 278                                                (int)(length - sizeof ia));
 279 }
 280
 281 void trace_icmp_input_stop (trace_type_t *ttype) { }
 282
 283 void trace_icmp_output_input (trace_type_t *ttype, unsigned length, char *buf)
 284 {
 285         struct iaddr ia;
 286
 287         if (length != (sizeof (struct icmp) + sizeof (ia))) {
 288                 log_error ("trace_icmp_output_input: data size mismatch %d:%d",
 289                            length, (int)(sizeof (struct icmp) + sizeof (ia)));
 290                 return;
 291         }
 292         ia.len = 4;
 293         memcpy (ia.iabuf, buf, 4);
 294
 295         log_error ("trace_icmp_output_input: unsent ping to %s", piaddr (ia));
 296 }
 297
 298 void trace_icmp_output_stop (trace_type_t *ttype) { }
 299 #endif /* TRACING */