The Tcpdump Group git mirrors - libpcap/blob - pcap-dbus.c

   1 /*
   2  * Copyright (c) 2012 Jakub Zawadzki
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  *
   9  * 1. Redistributions of source code must retain the above copyright
  10  * notice, this list of conditions and the following disclaimer.
  11  * 2. Redistributions in binary form must reproduce the above copyright
  12  * notice, this list of conditions and the following disclaimer in the
  13  * documentation and/or other materials provided with the distribution.
  14  * 3. The name of the author may not be used to endorse or promote
  15  * products derived from this software without specific prior written
  16  * permission.
  17  *
  18  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  19  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  20  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  21  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  22  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  23  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  24  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  25  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  26  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  27  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  28  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  29  */
  30
  31 #ifdef HAVE_CONFIG_H
  32 #include "config.h"
  33 #endif
  34
  35 #include <string.h>
  36
  37 #include <time.h>
  38 #include <sys/time.h>
  39
  40 #include <dbus/dbus.h>
  41
  42 #include "pcap-int.h"
  43 #include "pcap-dbus.h"
  44
  45 /*
  46  * Private data for capturing on D-Bus.
  47  */
  48 struct pcap_dbus {
  49         DBusConnection *conn;
  50         u_int   packets_read;   /* count of packets read */
  51 };
  52
  53 static int
  54 dbus_read(pcap_t *handle, int max_packets, pcap_handler callback, u_char *user)
  55 {
  56         struct pcap_dbus *handlep = handle->priv;
  57
  58         struct pcap_pkthdr pkth;
  59         DBusMessage *message;
  60
  61         char *raw_msg;
  62         int raw_msg_len;
  63
  64         int count = 0;
  65
  66         message = dbus_connection_pop_message(handlep->conn);
  67
  68         while (!message) {
  69                 /* XXX handle->opt.timeout = timeout_ms; */
  70                 if (!dbus_connection_read_write(handlep->conn, 100)) {
  71                         pcap_snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "Connection closed");
  72                         return -1;
  73                 }
  74
  75                 if (handle->break_loop) {
  76                         handle->break_loop = 0;
  77                         return -2;
  78                 }
  79
  80                 message = dbus_connection_pop_message(handlep->conn);
  81         }
  82
  83         if (dbus_message_is_signal(message, DBUS_INTERFACE_LOCAL, "Disconnected")) {
  84                 pcap_snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "Disconnected");
  85                 return -1;
  86         }
  87
  88         if (dbus_message_marshal(message, &raw_msg, &raw_msg_len)) {
  89                 pkth.caplen = pkth.len = raw_msg_len;
  90                 /* pkth.caplen = min (payload_len, handle->snapshot); */
  91
  92                 gettimeofday(&pkth.ts, NULL);
  93                 if (handle->fcode.bf_insns == NULL ||
  94                     bpf_filter(handle->fcode.bf_insns, (u_char *)raw_msg, pkth.len, pkth.caplen)) {
  95                         handlep->packets_read++;
  96                         callback(user, &pkth, (u_char *)raw_msg);
  97                         count++;
  98                 }
  99
 100                 dbus_free(raw_msg);
 101         }
 102         return count;
 103 }
 104
 105 static int
 106 dbus_write(pcap_t *handle, const void *buf, size_t size)
 107 {
 108         /* XXX, not tested */
 109         struct pcap_dbus *handlep = handle->priv;
 110
 111         DBusError error = DBUS_ERROR_INIT;
 112         DBusMessage *msg;
 113
 114         if (!(msg = dbus_message_demarshal(buf, size, &error))) {
 115                 pcap_snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "dbus_message_demarshal() failed: %s", error.message);
 116                 dbus_error_free(&error);
 117                 return -1;
 118         }
 119
 120         dbus_connection_send(handlep->conn, msg, NULL);
 121         dbus_connection_flush(handlep->conn);
 122
 123         dbus_message_unref(msg);
 124         return 0;
 125 }
 126
 127 static int
 128 dbus_stats(pcap_t *handle, struct pcap_stat *stats)
 129 {
 130         struct pcap_dbus *handlep = handle->priv;
 131
 132         stats->ps_recv = handlep->packets_read;
 133         stats->ps_drop = 0;
 134         stats->ps_ifdrop = 0;
 135         return 0;
 136 }
 137
 138 static void
 139 dbus_cleanup(pcap_t *handle)
 140 {
 141         struct pcap_dbus *handlep = handle->priv;
 142
 143         dbus_connection_unref(handlep->conn);
 144
 145         pcap_cleanup_live_common(handle);
 146 }
 147
 148 static int
 149 dbus_activate(pcap_t *handle)
 150 {
 151 #define EAVESDROPPING_RULE "eavesdrop=true,"
 152
 153         static const char *rules[] = {
 154                 EAVESDROPPING_RULE "type='signal'",
 155                 EAVESDROPPING_RULE "type='method_call'",
 156                 EAVESDROPPING_RULE "type='method_return'",
 157                 EAVESDROPPING_RULE "type='error'",
 158         };
 159
 160         #define N_RULES sizeof(rules)/sizeof(rules[0])
 161
 162         struct pcap_dbus *handlep = handle->priv;
 163         const char *dev = handle->opt.device;
 164
 165         DBusError error = DBUS_ERROR_INIT;
 166         u_int i;
 167
 168         if (strcmp(dev, "dbus-system") == 0) {
 169                 if (!(handlep->conn = dbus_bus_get(DBUS_BUS_SYSTEM, &error))) {
 170                         pcap_snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "Failed to get system bus: %s", error.message);
 171                         dbus_error_free(&error);
 172                         return PCAP_ERROR;
 173                 }
 174
 175         } else if (strcmp(dev, "dbus-session") == 0) {
 176                 if (!(handlep->conn = dbus_bus_get(DBUS_BUS_SESSION, &error))) {
 177                         pcap_snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "Failed to get session bus: %s", error.message);
 178                         dbus_error_free(&error);
 179                         return PCAP_ERROR;
 180                 }
 181
 182         } else if (strncmp(dev, "dbus://", 7) == 0) {
 183                 const char *addr = dev + 7;
 184
 185                 if (!(handlep->conn = dbus_connection_open(addr, &error))) {
 186                         pcap_snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "Failed to open connection to: %s: %s", addr, error.message);
 187                         dbus_error_free(&error);
 188                         return PCAP_ERROR;
 189                 }
 190
 191                 if (!dbus_bus_register(handlep->conn, &error)) {
 192                         pcap_snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "Failed to register bus %s: %s\n", addr, error.message);
 193                         dbus_error_free(&error);
 194                         return PCAP_ERROR;
 195                 }
 196
 197         } else {
 198                 pcap_snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "Can't get bus address from %s", handle->opt.device);
 199                 return PCAP_ERROR;
 200         }
 201
 202         /* Initialize some components of the pcap structure. */
 203         handle->bufsize = 0;
 204         handle->offset = 0;
 205         handle->linktype = DLT_DBUS;
 206         handle->read_op = dbus_read;
 207         handle->inject_op = dbus_write;
 208         handle->setfilter_op = install_bpf_program; /* XXX, later add support for dbus_bus_add_match() */
 209         handle->setdirection_op = NULL;
 210         handle->set_datalink_op = NULL;      /* can't change data link type */
 211         handle->getnonblock_op = pcap_getnonblock_fd;
 212         handle->setnonblock_op = pcap_setnonblock_fd;
 213         handle->stats_op = dbus_stats;
 214         handle->cleanup_op = dbus_cleanup;
 215
 216         handle->selectable_fd = handle->fd = -1;
 217
 218         if (handle->opt.rfmon) {
 219                 /*
 220                  * Monitor mode doesn't apply to dbus connections.
 221                  */
 222                 dbus_cleanup(handle);
 223                 return PCAP_ERROR_RFMON_NOTSUP;
 224         }
 225
 226         /* dbus_connection_set_max_message_size(handlep->conn, handle->snapshot); */
 227         if (handle->opt.buffer_size != 0)
 228                 dbus_connection_set_max_received_size(handlep->conn, handle->opt.buffer_size);
 229
 230         for (i = 0; i < N_RULES; i++) {
 231                 dbus_bus_add_match(handlep->conn, rules[i], &error);
 232                 if (dbus_error_is_set(&error)) {
 233                         dbus_error_free(&error);
 234
 235                         /* try without eavesdrop */
 236                         dbus_bus_add_match(handlep->conn, rules[i] + strlen(EAVESDROPPING_RULE), &error);
 237                         if (dbus_error_is_set(&error)) {
 238                                 pcap_snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "Failed to add bus match: %s\n", error.message);
 239                                 dbus_error_free(&error);
 240                                 dbus_cleanup(handle);
 241                                 return PCAP_ERROR;
 242                         }
 243                 }
 244         }
 245
 246         return 0;
 247 }
 248
 249 pcap_t *
 250 dbus_create(const char *device, char *ebuf, int *is_ours)
 251 {
 252         pcap_t *p;
 253
 254         if (strcmp(device, "dbus-system") &&
 255                 strcmp(device, "dbus-session") &&
 256                 strncmp(device, "dbus://", 7))
 257         {
 258                 *is_ours = 0;
 259                 return NULL;
 260         }
 261
 262         *is_ours = 1;
 263         p = pcap_create_common(ebuf, sizeof (struct pcap_dbus));
 264         if (p == NULL)
 265                 return (NULL);
 266
 267         p->activate_op = dbus_activate;
 268         return (p);
 269 }
 270
 271 int
 272 dbus_findalldevs(pcap_if_list_t *devlistp, char *err_str)
 273 {
 274         if (add_dev(devlistp, "dbus-system", 0, "D-Bus system bus", err_str) == NULL)
 275                 return -1;
 276         if (add_dev(devlistp, "dbus-session", 0, "D-Bus session bus", err_str) == NULL)
 277                 return -1;
 278         return 0;
 279 }
 280