1 /* $NetBSD: pcap-dbus.c,v 1.3 2015/03/31 21:39:42 christos Exp $ */
2
3 /*
4 * Copyright (c) 2012 Jakub Zawadzki
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 *
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 3. The name of the author may not be used to endorse or promote
17 * products derived from this software without specific prior written
18 * permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
21 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
22 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
23 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
24 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
25 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
26 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
27 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
28 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
29 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
30 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
31 */
32
33 #include <sys/cdefs.h>
34 __RCSID("$NetBSD: pcap-dbus.c,v 1.3 2015/03/31 21:39:42 christos Exp $");
35
36 #ifdef HAVE_CONFIG_H
37 #include "config.h"
38 #endif
39
40 #include <string.h>
41
42 #include <time.h>
43 #include <sys/time.h>
44
45 #include <dbus/dbus.h>
46
47 #include "pcap-int.h"
48 #include "pcap-dbus.h"
49
50 /*
51 * Private data for capturing on D-Bus.
52 */
53 struct pcap_dbus {
54 DBusConnection *conn;
55 u_int packets_read; /* count of packets read */
56 };
57
58 static int
dbus_read(pcap_t * handle,int max_packets,pcap_handler callback,u_char * user)59 dbus_read(pcap_t *handle, int max_packets, pcap_handler callback, u_char *user)
60 {
61 struct pcap_dbus *handlep = handle->priv;
62
63 struct pcap_pkthdr pkth;
64 DBusMessage *message;
65
66 char *raw_msg;
67 int raw_msg_len;
68
69 int count = 0;
70
71 message = dbus_connection_pop_message(handlep->conn);
72
73 while (!message) {
74 // XXX handle->opt.timeout = timeout_ms;
75 if (!dbus_connection_read_write(handlep->conn, 100)) {
76 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "Connection closed");
77 return -1;
78 }
79
80 if (handle->break_loop) {
81 handle->break_loop = 0;
82 return -2;
83 }
84
85 message = dbus_connection_pop_message(handlep->conn);
86 }
87
88 if (dbus_message_is_signal(message, DBUS_INTERFACE_LOCAL, "Disconnected")) {
89 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "Disconnected");
90 return -1;
91 }
92
93 if (dbus_message_marshal(message, &raw_msg, &raw_msg_len)) {
94 pkth.caplen = pkth.len = raw_msg_len;
95 /* pkth.caplen = min (payload_len, handle->snapshot); */
96
97 gettimeofday(&pkth.ts, NULL);
98 if (handle->fcode.bf_insns == NULL ||
99 bpf_filter(handle->fcode.bf_insns, (u_char *)raw_msg, pkth.len, pkth.caplen)) {
100 handlep->packets_read++;
101 callback(user, &pkth, (u_char *)raw_msg);
102 count++;
103 }
104
105 dbus_free(raw_msg);
106 }
107 return count;
108 }
109
110 static int
dbus_write(pcap_t * handle,const void * buf,size_t size)111 dbus_write(pcap_t *handle, const void *buf, size_t size)
112 {
113 /* XXX, not tested */
114 struct pcap_dbus *handlep = handle->priv;
115
116 DBusError error = DBUS_ERROR_INIT;
117 DBusMessage *msg;
118
119 if (!(msg = dbus_message_demarshal(buf, size, &error))) {
120 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "dbus_message_demarshal() failed: %s", error.message);
121 dbus_error_free(&error);
122 return -1;
123 }
124
125 dbus_connection_send(handlep->conn, msg, NULL);
126 dbus_connection_flush(handlep->conn);
127
128 dbus_message_unref(msg);
129 return 0;
130 }
131
132 static int
dbus_stats(pcap_t * handle,struct pcap_stat * stats)133 dbus_stats(pcap_t *handle, struct pcap_stat *stats)
134 {
135 struct pcap_dbus *handlep = handle->priv;
136
137 stats->ps_recv = handlep->packets_read;
138 stats->ps_drop = 0;
139 stats->ps_ifdrop = 0;
140 return 0;
141 }
142
143 static void
dbus_cleanup(pcap_t * handle)144 dbus_cleanup(pcap_t *handle)
145 {
146 struct pcap_dbus *handlep = handle->priv;
147
148 dbus_connection_unref(handlep->conn);
149
150 pcap_cleanup_live_common(handle);
151 }
152
153 static int
dbus_activate(pcap_t * handle)154 dbus_activate(pcap_t *handle)
155 {
156 #define EAVESDROPPING_RULE "eavesdrop=true,"
157
158 static const char *rules[] = {
159 EAVESDROPPING_RULE "type='signal'",
160 EAVESDROPPING_RULE "type='method_call'",
161 EAVESDROPPING_RULE "type='method_return'",
162 EAVESDROPPING_RULE "type='error'",
163 };
164
165 #define N_RULES sizeof(rules)/sizeof(rules[0])
166
167 struct pcap_dbus *handlep = handle->priv;
168 const char *dev = handle->opt.source;
169
170 DBusError error = DBUS_ERROR_INIT;
171 int i;
172
173 if (strcmp(dev, "dbus-system") == 0) {
174 if (!(handlep->conn = dbus_bus_get(DBUS_BUS_SYSTEM, &error))) {
175 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "Failed to get system bus: %s", error.message);
176 dbus_error_free(&error);
177 return PCAP_ERROR;
178 }
179
180 } else if (strcmp(dev, "dbus-session") == 0) {
181 if (!(handlep->conn = dbus_bus_get(DBUS_BUS_SESSION, &error))) {
182 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "Failed to get session bus: %s", error.message);
183 dbus_error_free(&error);
184 return PCAP_ERROR;
185 }
186
187 } else if (strncmp(dev, "dbus://", 7) == 0) {
188 const char *addr = dev + 7;
189
190 if (!(handlep->conn = dbus_connection_open(addr, &error))) {
191 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "Failed to open connection to: %s: %s", addr, error.message);
192 dbus_error_free(&error);
193 return PCAP_ERROR;
194 }
195
196 if (!dbus_bus_register(handlep->conn, &error)) {
197 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "Failed to register bus %s: %s\n", addr, error.message);
198 dbus_error_free(&error);
199 return PCAP_ERROR;
200 }
201
202 } else {
203 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "Can't get bus address from %s", handle->opt.source);
204 return PCAP_ERROR;
205 }
206
207 /* Initialize some components of the pcap structure. */
208 handle->bufsize = 0;
209 handle->offset = 0;
210 handle->linktype = DLT_DBUS;
211 handle->read_op = dbus_read;
212 handle->inject_op = dbus_write;
213 handle->setfilter_op = install_bpf_program; /* XXX, later add support for dbus_bus_add_match() */
214 handle->setdirection_op = NULL;
215 handle->set_datalink_op = NULL; /* can't change data link type */
216 handle->getnonblock_op = pcap_getnonblock_fd;
217 handle->setnonblock_op = pcap_setnonblock_fd;
218 handle->stats_op = dbus_stats;
219
220 handle->selectable_fd = handle->fd = -1;
221
222 if (handle->opt.rfmon) {
223 /*
224 * Monitor mode doesn't apply to dbus connections.
225 */
226 dbus_cleanup(handle);
227 return PCAP_ERROR_RFMON_NOTSUP;
228 }
229
230 /* dbus_connection_set_max_message_size(handlep->conn, handle->snapshot); */
231 if (handle->opt.buffer_size != 0)
232 dbus_connection_set_max_received_size(handlep->conn, handle->opt.buffer_size);
233
234 for (i = 0; i < N_RULES; i++) {
235 dbus_bus_add_match(handlep->conn, rules[i], &error);
236 if (dbus_error_is_set(&error)) {
237 dbus_error_free(&error);
238
239 /* try without eavesdrop */
240 dbus_bus_add_match(handlep->conn, rules[i] + strlen(EAVESDROPPING_RULE), &error);
241 if (dbus_error_is_set(&error)) {
242 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "Failed to add bus match: %s\n", error.message);
243 dbus_error_free(&error);
244 dbus_cleanup(handle);
245 return PCAP_ERROR;
246 }
247 }
248 }
249
250 return 0;
251 }
252
253 pcap_t *
dbus_create(const char * device,char * ebuf,int * is_ours)254 dbus_create(const char *device, char *ebuf, int *is_ours)
255 {
256 pcap_t *p;
257
258 if (strcmp(device, "dbus-system") &&
259 strcmp(device, "dbus-session") &&
260 strncmp(device, "dbus://", 7))
261 {
262 *is_ours = 0;
263 return NULL;
264 }
265
266 *is_ours = 1;
267 p = pcap_create_common(device, ebuf, sizeof (struct pcap_dbus));
268 if (p == NULL)
269 return (NULL);
270
271 p->activate_op = dbus_activate;
272 return (p);
273 }
274
275 int
dbus_findalldevs(pcap_if_t ** alldevsp,char * err_str)276 dbus_findalldevs(pcap_if_t **alldevsp, char *err_str)
277 {
278 if (pcap_add_if(alldevsp, "dbus-system", 0, "D-Bus system bus", err_str) < 0)
279 return -1;
280 if (pcap_add_if(alldevsp, "dbus-session", 0, "D-Bus session bus", err_str) < 0)
281 return -1;
282 return 0;
283 }
284
285