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 */
48struct pcap_dbus {
49	DBusConnection *conn;
50	u_int	packets_read;	/* count of packets read */
51};
52
53static int
54dbus_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			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		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
105static int
106dbus_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		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
127static int
128dbus_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
138static void
139dbus_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
148static int
149dbus_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.source;
164
165	DBusError error = DBUS_ERROR_INIT;
166	int i;
167
168	if (strcmp(dev, "dbus-system") == 0) {
169		if (!(handlep->conn = dbus_bus_get(DBUS_BUS_SYSTEM, &error))) {
170			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			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			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			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		snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "Can't get bus address from %s", handle->opt.source);
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
215	handle->selectable_fd = handle->fd = -1;
216
217	if (handle->opt.rfmon) {
218		/*
219		 * Monitor mode doesn't apply to dbus connections.
220		 */
221		dbus_cleanup(handle);
222		return PCAP_ERROR_RFMON_NOTSUP;
223	}
224
225	/* dbus_connection_set_max_message_size(handlep->conn, handle->snapshot); */
226	if (handle->opt.buffer_size != 0)
227		dbus_connection_set_max_received_size(handlep->conn, handle->opt.buffer_size);
228
229	for (i = 0; i < N_RULES; i++) {
230		dbus_bus_add_match(handlep->conn, rules[i], &error);
231		if (dbus_error_is_set(&error)) {
232			dbus_error_free(&error);
233
234			/* try without eavesdrop */
235			dbus_bus_add_match(handlep->conn, rules[i] + strlen(EAVESDROPPING_RULE), &error);
236			if (dbus_error_is_set(&error)) {
237				snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "Failed to add bus match: %s\n", error.message);
238				dbus_error_free(&error);
239				dbus_cleanup(handle);
240				return PCAP_ERROR;
241			}
242		}
243	}
244
245	return 0;
246}
247
248pcap_t *
249dbus_create(const char *device, char *ebuf, int *is_ours)
250{
251	pcap_t *p;
252
253	if (strcmp(device, "dbus-system") &&
254		strcmp(device, "dbus-session") &&
255		strncmp(device, "dbus://", 7))
256	{
257		*is_ours = 0;
258		return NULL;
259	}
260
261	*is_ours = 1;
262	p = pcap_create_common(device, ebuf, sizeof (struct pcap_dbus));
263	if (p == NULL)
264		return (NULL);
265
266	p->activate_op = dbus_activate;
267	return (p);
268}
269
270int
271dbus_findalldevs(pcap_if_t **alldevsp, char *err_str)
272{
273	if (pcap_add_if(alldevsp, "dbus-system", 0, "D-Bus system bus", err_str) < 0)
274		return -1;
275	if (pcap_add_if(alldevsp, "dbus-session", 0, "D-Bus session bus", err_str) < 0)
276		return -1;
277	return 0;
278}
279
280