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 static int
  46 dbus_read(pcap_t *handle, int max_packets, pcap_handler callback, u_char *user)
  47 {
  48         DBusConnection *conn = handle->md.priv;
  49
  50         struct pcap_pkthdr pkth;
  51         DBusMessage *message;
  52
  53         char *raw_msg;
  54         int raw_msg_len;
  55
  56         int count = 0;
  57
  58         message = dbus_connection_pop_message(conn);
  59
  60         while (!message) {
  61                 // XXX p->md.timeout = timeout_ms;
  62                 if (!dbus_connection_read_write(conn, 100)) {
  63                         snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "Connection closed");
  64                         return -1;
  65                 }
  66
  67                 if (handle->break_loop) {
  68                         handle->break_loop = 0;
  69                         return -2;
  70                 }
  71
  72                 message = dbus_connection_pop_message(conn);
  73         }
  74
  75         if (dbus_message_is_signal(message, DBUS_INTERFACE_LOCAL, "Disconnected")) {
  76                 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "Disconnected");
  77                 return -1;
  78         }
  79
  80         if (dbus_message_marshal(message, &raw_msg, &raw_msg_len)) {
  81                 pkth.caplen = pkth.len = raw_msg_len;
  82                 /* pkth.caplen = min (payload_len, handle->snapshot); */
  83
  84                 gettimeofday(&pkth.ts, NULL);
  85                 if (handle->fcode.bf_insns == NULL ||
  86                     bpf_filter(handle->fcode.bf_insns, (u_char *)raw_msg, pkth.len, pkth.caplen)) {
  87                         handle->md.packets_read++;
  88                         callback(user, &pkth, (u_char *)raw_msg);
  89                         count++;
  90                 }
  91
  92                 dbus_free(raw_msg);
  93         }
  94         return count;
  95 }
  96
  97 static int
  98 dbus_write(pcap_t *handle, const void *buf, size_t size)
  99 {
 100         /* XXX, not tested */
 101         DBusConnection *conn = handle->md.priv;
 102
 103         DBusError error = DBUS_ERROR_INIT;
 104         DBusMessage *msg;
 105
 106         if (!(msg = dbus_message_demarshal(buf, size, &error))) {
 107                 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "dbus_message_demarshal() failed: %s", error.message);
 108                 dbus_error_free(&error);
 109                 return -1;
 110         }
 111
 112         dbus_connection_send(conn, msg, NULL);
 113         dbus_connection_flush(conn);
 114
 115         dbus_message_unref(msg);
 116         return 0;
 117 }
 118
 119 static int
 120 dbus_stats(pcap_t *handle, struct pcap_stat *stats)
 121 {
 122         stats->ps_recv = handle->md.packets_read;
 123         stats->ps_drop = 0;
 124         stats->ps_ifdrop = 0;
 125         return 0;
 126 }
 127
 128 static void
 129 dbus_cleanup(pcap_t *handle)
 130 {
 131         DBusConnection *conn = handle->md.priv;
 132
 133         handle->md.priv = NULL;
 134         dbus_connection_unref(conn);
 135
 136         pcap_cleanup_live_common(handle);
 137 }
 138
 139 static int
 140 dbus_activate(pcap_t *handle)
 141 {
 142 #define EAVESDROPPING_RULE "eavesdrop=true,"
 143
 144         static const char *rules[] = {
 145                 EAVESDROPPING_RULE "type='signal'",
 146                 EAVESDROPPING_RULE "type='method_call'",
 147                 EAVESDROPPING_RULE "type='method_return'",
 148                 EAVESDROPPING_RULE "type='error'",
 149         };
 150
 151         #define N_RULES sizeof(rules)/sizeof(rules[0])
 152
 153         const char *dev = handle->opt.source;
 154
 155         DBusError error = DBUS_ERROR_INIT;
 156         DBusConnection *conn;
 157         int i;
 158
 159         if (strcmp(dev, "dbus-system") == 0) {
 160                 if (!(conn = dbus_bus_get(DBUS_BUS_SYSTEM, &error))) {
 161                         snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "Failed to get system bus: %s", error.message);
 162                         dbus_error_free(&error);
 163                         return PCAP_ERROR;
 164                 }
 165
 166         } else if (strcmp(dev, "dbus-session") == 0) {
 167                 if (!(conn = dbus_bus_get(DBUS_BUS_SESSION, &error))) {
 168                         snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "Failed to get session bus: %s", error.message);
 169                         dbus_error_free(&error);
 170                         return PCAP_ERROR;
 171                 }
 172
 173         } else if (strncmp(dev, "dbus://", 7) == 0) {
 174                 const char *addr = dev + 7;
 175
 176                 if (!(conn = dbus_connection_open(addr, &error))) {
 177                         snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "Failed to open connection to: %s: %s", addr, error.message);
 178                         dbus_error_free(&error);
 179                         return PCAP_ERROR;
 180                 }
 181
 182                 if (!dbus_bus_register(conn, &error)) {
 183                         snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "Failed to register bus %s: %s\n", addr, error.message);
 184                         dbus_error_free(&error);
 185                         return PCAP_ERROR;
 186                 }
 187
 188         } else {
 189                 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "Can't get bus address from %s", handle->opt.source);
 190                 return PCAP_ERROR;
 191         }
 192
 193         /* Initialize some components of the pcap structure. */
 194         handle->bufsize = 0;
 195         handle->offset = 0;
 196         handle->linktype = DLT_DBUS;
 197         handle->read_op = dbus_read;
 198         handle->inject_op = dbus_write;
 199         handle->setfilter_op = install_bpf_program; /* XXX, later add support for dbus_bus_add_match() */
 200         handle->setdirection_op = NULL;
 201         handle->set_datalink_op = NULL;      /* can't change data link type */
 202         handle->getnonblock_op = pcap_getnonblock_fd;
 203         handle->setnonblock_op = pcap_setnonblock_fd;
 204         handle->stats_op = dbus_stats;
 205
 206         handle->selectable_fd = handle->fd = -1;
 207         handle->md.priv = conn;
 208
 209         if (handle->opt.rfmon) {
 210                 /*
 211                  * Monitor mode doesn't apply to dbus connections.
 212                  */
 213                 dbus_cleanup(handle);
 214                 return PCAP_ERROR_RFMON_NOTSUP;
 215         }
 216
 217         /* dbus_connection_set_max_message_size(conn, handle->snapshot); */
 218         if (handle->opt.buffer_size != 0)
 219                 dbus_connection_set_max_received_size(conn, handle->opt.buffer_size);
 220
 221         for (i = 0; i < N_RULES; i++) {
 222                 dbus_bus_add_match(conn, rules[i], &error);
 223                 if (dbus_error_is_set(&error)) {
 224                         dbus_error_free(&error);
 225
 226                         /* try without eavesdrop */
 227                         dbus_bus_add_match(conn, rules[i] + strlen(EAVESDROPPING_RULE), &error);
 228                         if (dbus_error_is_set(&error)) {
 229                                 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "Failed to add bus match: %s\n", error.message);
 230                                 dbus_error_free(&error);
 231                                 dbus_cleanup(handle);
 232                                 return PCAP_ERROR;
 233                         }
 234                 }
 235         }
 236
 237         return 0;
 238 }
 239
 240 pcap_t *
 241 dbus_create(const char *device, char *ebuf, int *is_ours)
 242 {
 243         pcap_t *p;
 244
 245         if (strcmp(device, "dbus-system") &&
 246                 strcmp(device, "dbus-session") &&
 247                 strncmp(device, "dbus://", 7))
 248         {
 249                 *is_ours = 0;
 250                 return NULL;
 251         }
 252
 253         *is_ours = 1;
 254         p = pcap_create_common(device, ebuf);
 255         if (p == NULL)
 256                 return (NULL);
 257
 258         p->activate_op = dbus_activate;
 259         return (p);
 260 }
 261
 262 int
 263 dbus_findalldevs(pcap_if_t **alldevsp, char *err_str)
 264 {
 265         pcap_if_t *found_dev = *alldevsp;
 266
 267         if (pcap_add_if(&found_dev, "dbus-system", 0, "D-BUS system bus", err_str) < 0)
 268                 return -1;
 269         if (pcap_add_if(&found_dev, "dbus-session", 0, "D-BUS session bus", err_str) < 0)
 270                 return -1;
 271         return 0;
 272 }
 273