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 "pcap-int.h"
  36
  37 #include <string.h>
  38
  39 #include <time.h>
  40 #include <sys/time.h>
  41
  42 #include <dbus/dbus.h>
  43
  44 static int
  45 dbus_read(pcap_t *handle, int max_packets, pcap_handler callback, u_char *user)
  46 {
  47         DBusConnection *conn = handle->md.priv;
  48
  49         struct pcap_pkthdr pkth;
  50         DBusMessage *message;
  51
  52         char *raw_msg;
  53         int raw_msg_len;
  54
  55         int count = 0;
  56
  57         message = dbus_connection_pop_message(conn);
  58
  59         while (!message) {
  60                 // XXX p->md.timeout = timeout_ms;
  61                 if (!dbus_connection_read_write(conn, 100)) {
  62                         snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "Connection closed");
  63                         return -1;
  64                 }
  65
  66                 if (handle->break_loop) {
  67                         handle->break_loop = 0;
  68                         return -2;
  69                 }
  70
  71                 message = dbus_connection_pop_message(conn);
  72         }
  73
  74         if (dbus_message_is_signal(message, DBUS_INTERFACE_LOCAL, "Disconnected")) {
  75                 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "Disconnected");
  76                 return -1;
  77         }
  78
  79         if (dbus_message_marshal(message, &raw_msg, &raw_msg_len)) {
  80                 pkth.caplen = pkth.len = raw_msg_len;
  81                 /* pkth.caplen = min (payload_len, handle->snapshot); */
  82
  83                 gettimeofday(&pkth.ts, NULL);
  84                 if (handle->fcode.bf_insns == NULL || bpf_filter(handle->fcode.bf_insns, raw_msg, pkth.len, pkth.caplen)) {
  85                         handle->md.packets_read++;
  86                         callback(user, &pkth, raw_msg);
  87                         count++;
  88                 }
  89
  90                 dbus_free(raw_msg);
  91         }
  92         return count;
  93 }
  94
  95 static int
  96 dbus_write(pcap_t *handle, const void *buf, size_t size)
  97 {
  98         /* XXX, not tested */
  99         DBusConnection *conn = handle->md.priv;
 100
 101         DBusError error = DBUS_ERROR_INIT;
 102         DBusMessage *msg;
 103
 104         if (!(msg = dbus_message_demarshal(buf, size, &error))) {
 105                 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "dbus_message_demarshal() failed: %s", error.message);
 106                 dbus_error_free(&error);
 107                 return -1;
 108         }
 109
 110         dbus_connection_send(conn, msg, NULL);
 111         dbus_connection_flush(conn);
 112
 113         dbus_message_unref(msg);
 114         return 0;
 115 }
 116
 117 static int
 118 dbus_stats(pcap_t *handle, struct pcap_stat *stats)
 119 {
 120         stats->ps_recv = handle->md.packets_read;
 121         stats->ps_drop = 0;
 122         stats->ps_ifdrop = 0;
 123         return 0;
 124 }
 125
 126 static void
 127 dbus_cleanup(pcap_t *handle)
 128 {
 129         DBusConnection *conn = handle->md.priv;
 130
 131         handle->md.priv = NULL;
 132         dbus_connection_unref(conn);
 133
 134         pcap_cleanup_live_common(handle);
 135 }
 136
 137 static int
 138 dbus_activate(pcap_t *handle)
 139 {
 140 #define EAVESDROPPING_RULE "eavesdrop=true,"
 141
 142         static const char *rules[] = {
 143                 EAVESDROPPING_RULE "type='signal'",
 144                 EAVESDROPPING_RULE "type='method_call'",
 145                 EAVESDROPPING_RULE "type='method_return'",
 146                 EAVESDROPPING_RULE "type='error'",
 147         };
 148
 149         #define N_RULES sizeof(rules)/sizeof(rules[0])
 150
 151         const char *dev = handle->opt.source;
 152
 153         DBusError error = DBUS_ERROR_INIT;
 154         DBusConnection *conn;
 155         int i;
 156
 157         if (strcmp(dev, "dbus-system") == 0) {
 158                 if (!(conn = dbus_bus_get(DBUS_BUS_SYSTEM, &error))) {
 159                         snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "Failed to get system bus: %s", error.message);
 160                         dbus_error_free(&error);
 161                         return PCAP_ERROR;
 162                 }
 163
 164         } else if (strcmp(dev, "dbus-session") == 0) {
 165                 if (!(conn = dbus_bus_get(DBUS_BUS_SESSION, &error))) {
 166                         snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "Failed to get session bus: %s", error.message);
 167                         dbus_error_free(&error);
 168                         return PCAP_ERROR;
 169                 }
 170
 171         } else if (strncmp(dev, "dbus://", 7) == 0) {
 172                 const char *addr = dev + 7;
 173
 174                 if (!(conn = dbus_connection_open(addr, &error))) {
 175                         snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "Failed to open connection to: %s: %s", addr, error.message);
 176                         dbus_error_free(&error);
 177                         return PCAP_ERROR;
 178                 }
 179
 180                 if (!dbus_bus_register(conn, &error)) {
 181                         snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "Failed to register bus %s: %s\n", addr, error.message);
 182                         dbus_error_free(&error);
 183                         return PCAP_ERROR;
 184                 }
 185
 186         } else {
 187                 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "Can't get bus address from %s", handle->opt.source);
 188                 return PCAP_ERROR;
 189         }
 190
 191         /* Initialize some components of the pcap structure. */
 192         handle->bufsize = 0;
 193         handle->offset = 0;
 194         handle->linktype = DLT_DBUS;
 195         handle->read_op = dbus_read;
 196         handle->inject_op = dbus_write;
 197         handle->setfilter_op = install_bpf_program; /* XXX, later add support for dbus_bus_add_match() */
 198         handle->setdirection_op = NULL;
 199         handle->set_datalink_op = NULL;      /* can't change data link type */
 200         handle->getnonblock_op = pcap_getnonblock_fd;
 201         handle->setnonblock_op = pcap_setnonblock_fd;
 202         handle->stats_op = dbus_stats;
 203
 204         handle->selectable_fd = handle->fd = -1;
 205         handle->md.priv = conn;
 206
 207         if (handle->opt.rfmon) {
 208                 /*
 209                  * Monitor mode doesn't apply to dbus connections.
 210                  */
 211                 dbus_cleanup(handle);
 212                 return PCAP_ERROR_RFMON_NOTSUP;
 213         }
 214
 215         /* dbus_connection_set_max_message_size(conn, handle->snapshot); */
 216         if (handle->opt.buffer_size != 0)
 217                 dbus_connection_set_max_received_size(conn, handle->opt.buffer_size);
 218
 219         for (i = 0; i < N_RULES; i++) {
 220                 dbus_bus_add_match(conn, rules[i], &error);
 221                 if (dbus_error_is_set(&error)) {
 222                         dbus_error_free(&error);
 223
 224                         /* try without eavesdrop */
 225                         dbus_bus_add_match(conn, rules[i] + strlen(EAVESDROPPING_RULE), &error);
 226                         if (dbus_error_is_set(&error)) {
 227                                 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "Failed to add bus match: %s\n", error.message);
 228                                 dbus_error_free(&error);
 229                                 dbus_cleanup(handle);
 230                                 return PCAP_ERROR;
 231                         }
 232                 }
 233         }
 234
 235         return 0;
 236 }
 237
 238 pcap_t *
 239 dbus_create(const char *device, char *ebuf, int *is_ours)
 240 {
 241         pcap_t *p;
 242
 243         if (strcmp(device, "dbus-system") &&
 244                 strcmp(device, "dbus-session") &&
 245                 strncmp(device, "dbus://", 7))
 246         {
 247                 *is_ours = 0;
 248                 return NULL;
 249         }
 250
 251         *is_ours = 1;
 252         p = pcap_create_common(device, ebuf);
 253         if (p == NULL)
 254                 return (NULL);
 255
 256         p->activate_op = dbus_activate;
 257         return (p);
 258 }
 259
 260 int
 261 dbus_findalldevs(pcap_if_t **alldevsp, char *err_str)
 262 {
 263         pcap_if_t *found_dev = *alldevsp;
 264
 265         if (pcap_add_if(&found_dev, "dbus-system", 0, "D-BUS system bus", err_str) < 0)
 266                 return -1;
 267         if (pcap_add_if(&found_dev, "dbus-session", 0, "D-BUS session bus", err_str) < 0)
 268                 return -1;
 269         return 0;
 270 }
 271