nexmon – Rev 1
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/*
* Copyright (c) 2012 Jakub Zawadzki
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote
* products derived from this software without specific prior written
* permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <string.h>
#include <time.h>
#include <sys/time.h>
#include <dbus/dbus.h>
#include "pcap-int.h"
#include "pcap-dbus.h"
/*
* Private data for capturing on D-Bus.
*/
struct pcap_dbus {
DBusConnection *conn;
u_int packets_read; /* count of packets read */
};
static int
dbus_read(pcap_t *handle, int max_packets, pcap_handler callback, u_char *user)
{
struct pcap_dbus *handlep = handle->priv;
struct pcap_pkthdr pkth;
DBusMessage *message;
char *raw_msg;
int raw_msg_len;
int count = 0;
message = dbus_connection_pop_message(handlep->conn);
while (!message) {
// XXX handle->opt.timeout = timeout_ms;
if (!dbus_connection_read_write(handlep->conn, 100)) {
snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "Connection closed");
return -1;
}
if (handle->break_loop) {
handle->break_loop = 0;
return -2;
}
message = dbus_connection_pop_message(handlep->conn);
}
if (dbus_message_is_signal(message, DBUS_INTERFACE_LOCAL, "Disconnected")) {
snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "Disconnected");
return -1;
}
if (dbus_message_marshal(message, &raw_msg, &raw_msg_len)) {
pkth.caplen = pkth.len = raw_msg_len;
/* pkth.caplen = min (payload_len, handle->snapshot); */
gettimeofday(&pkth.ts, NULL);
if (handle->fcode.bf_insns == NULL ||
bpf_filter(handle->fcode.bf_insns, (u_char *)raw_msg, pkth.len, pkth.caplen)) {
handlep->packets_read++;
callback(user, &pkth, (u_char *)raw_msg);
count++;
}
dbus_free(raw_msg);
}
return count;
}
static int
dbus_write(pcap_t *handle, const void *buf, size_t size)
{
/* XXX, not tested */
struct pcap_dbus *handlep = handle->priv;
DBusError error = DBUS_ERROR_INIT;
DBusMessage *msg;
if (!(msg = dbus_message_demarshal(buf, size, &error))) {
snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "dbus_message_demarshal() failed: %s", error.message);
dbus_error_free(&error);
return -1;
}
dbus_connection_send(handlep->conn, msg, NULL);
dbus_connection_flush(handlep->conn);
dbus_message_unref(msg);
return 0;
}
static int
dbus_stats(pcap_t *handle, struct pcap_stat *stats)
{
struct pcap_dbus *handlep = handle->priv;
stats->ps_recv = handlep->packets_read;
stats->ps_drop = 0;
stats->ps_ifdrop = 0;
return 0;
}
static void
dbus_cleanup(pcap_t *handle)
{
struct pcap_dbus *handlep = handle->priv;
dbus_connection_unref(handlep->conn);
pcap_cleanup_live_common(handle);
}
static int
dbus_activate(pcap_t *handle)
{
#define EAVESDROPPING_RULE "eavesdrop=true,"
static const char *rules[] = {
EAVESDROPPING_RULE "type='signal'",
EAVESDROPPING_RULE "type='method_call'",
EAVESDROPPING_RULE "type='method_return'",
EAVESDROPPING_RULE "type='error'",
};
#define N_RULES sizeof(rules)/sizeof(rules[0])
struct pcap_dbus *handlep = handle->priv;
const char *dev = handle->opt.source;
DBusError error = DBUS_ERROR_INIT;
int i;
if (strcmp(dev, "dbus-system") == 0) {
if (!(handlep->conn = dbus_bus_get(DBUS_BUS_SYSTEM, &error))) {
snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "Failed to get system bus: %s", error.message);
dbus_error_free(&error);
return PCAP_ERROR;
}
} else if (strcmp(dev, "dbus-session") == 0) {
if (!(handlep->conn = dbus_bus_get(DBUS_BUS_SESSION, &error))) {
snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "Failed to get session bus: %s", error.message);
dbus_error_free(&error);
return PCAP_ERROR;
}
} else if (strncmp(dev, "dbus://", 7) == 0) {
const char *addr = dev + 7;
if (!(handlep->conn = dbus_connection_open(addr, &error))) {
snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "Failed to open connection to: %s: %s", addr, error.message);
dbus_error_free(&error);
return PCAP_ERROR;
}
if (!dbus_bus_register(handlep->conn, &error)) {
snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "Failed to register bus %s: %s\n", addr, error.message);
dbus_error_free(&error);
return PCAP_ERROR;
}
} else {
snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "Can't get bus address from %s", handle->opt.source);
return PCAP_ERROR;
}
/* Initialize some components of the pcap structure. */
handle->bufsize = 0;
handle->offset = 0;
handle->linktype = DLT_DBUS;
handle->read_op = dbus_read;
handle->inject_op = dbus_write;
handle->setfilter_op = install_bpf_program; /* XXX, later add support for dbus_bus_add_match() */
handle->setdirection_op = NULL;
handle->set_datalink_op = NULL; /* can't change data link type */
handle->getnonblock_op = pcap_getnonblock_fd;
handle->setnonblock_op = pcap_setnonblock_fd;
handle->stats_op = dbus_stats;
handle->selectable_fd = handle->fd = -1;
if (handle->opt.rfmon) {
/*
* Monitor mode doesn't apply to dbus connections.
*/
dbus_cleanup(handle);
return PCAP_ERROR_RFMON_NOTSUP;
}
/* dbus_connection_set_max_message_size(handlep->conn, handle->snapshot); */
if (handle->opt.buffer_size != 0)
dbus_connection_set_max_received_size(handlep->conn, handle->opt.buffer_size);
for (i = 0; i < N_RULES; i++) {
dbus_bus_add_match(handlep->conn, rules[i], &error);
if (dbus_error_is_set(&error)) {
dbus_error_free(&error);
/* try without eavesdrop */
dbus_bus_add_match(handlep->conn, rules[i] + strlen(EAVESDROPPING_RULE), &error);
if (dbus_error_is_set(&error)) {
snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "Failed to add bus match: %s\n", error.message);
dbus_error_free(&error);
dbus_cleanup(handle);
return PCAP_ERROR;
}
}
}
return 0;
}
pcap_t *
dbus_create(const char *device, char *ebuf, int *is_ours)
{
pcap_t *p;
if (strcmp(device, "dbus-system") &&
strcmp(device, "dbus-session") &&
strncmp(device, "dbus://", 7))
{
*is_ours = 0;
return NULL;
}
*is_ours = 1;
p = pcap_create_common(device, ebuf, sizeof (struct pcap_dbus));
if (p == NULL)
return (NULL);
p->activate_op = dbus_activate;
return (p);
}
int
dbus_findalldevs(pcap_if_t **alldevsp, char *err_str)
{
if (pcap_add_if(alldevsp, "dbus-system", 0, "D-Bus system bus", err_str) < 0)
return -1;
if (pcap_add_if(alldevsp, "dbus-session", 0, "D-Bus session bus", err_str) < 0)
return -1;
return 0;
}