2 * interface monitor by Pontus Fuchs <pontus.fuchs@gmail.com>
6 * Wireshark - Network traffic analyzer
7 * By Gerald Combs <gerald@wireshark.org>
8 * Copyright 1998 Gerald Combs
10 * This program is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU General Public License
12 * as published by the Free Software Foundation; either version 2
13 * of the License, or (at your option) any later version.
15 * This program is distributed in the hope that it will be useful,
16 * but WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 * GNU General Public License for more details.
20 * You should have received a copy of the GNU General Public License
21 * along with this program; if not, write to the Free Software
22 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
28 #include "iface_monitor.h"
30 #if defined(HAVE_LIBNL)
40 #include <netlink/msg.h>
41 #include <netlink/attr.h>
42 #include <netlink/route/link.h>
46 * Apparently, some versions of libnl drag in headers that define IFF_UP
47 * and others don't. Include <net/if.h> iff IFF_UP isn't already defined,
48 * so that if <linux/if.h> has been included by some or all of the
49 * netlink headers, we don't include <net/if.h> and get a bunch of
50 * complaints about various structures being redefined.
55 /* libnl 1.x compatibility code */
57 #define nl_sock nl_handle
58 #define nl_socket_disable_seq_check nl_disable_sequence_check
60 static inline struct nl_handle *nl_socket_alloc(void)
62 return nl_handle_alloc();
65 static inline void nl_socket_free(struct nl_sock *h)
69 #endif /* HAVE_LIBNL1 */
71 static struct nl_sock *iface_mon_sock;
74 iface_mon_handler2(struct nl_object *obj, void *arg)
76 struct rtnl_link *filter;
77 struct rtnl_link *link_obj;
80 iface_mon_cb cb = arg;
82 filter = rtnl_link_alloc();
84 fprintf(stderr, "error allocating filter\n");
88 if (nl_object_match_filter (obj, OBJ_CAST (filter)) == 0) {
89 rtnl_link_put(filter);
93 link_obj = (struct rtnl_link *) obj;
94 flags = rtnl_link_get_flags (link_obj);
95 ifname = rtnl_link_get_name(link_obj);
98 * You can't bind a PF_PACKET socket to an interface that's not
99 * up, so an interface going down is an "interface should be
100 * removed" indication.
102 * XXX - what indication, if any, do we get if the interface
103 * *completely goes away*?
105 * XXX - can we get events if an interface's link-layer or
106 * network addresses change?
108 up = (flags & IFF_UP) ? 1 : 0;
112 rtnl_link_put(filter);
118 iface_mon_handler(struct nl_msg *msg, void *arg)
120 nl_msg_parse (msg, &iface_mon_handler2, arg);
125 iface_mon_event(void)
127 nl_recvmsgs_default(iface_mon_sock);
131 iface_mon_get_sock(void)
133 return nl_socket_get_fd(iface_mon_sock);
137 iface_mon_start(iface_mon_cb cb)
141 iface_mon_sock = nl_socket_alloc();
142 if (!iface_mon_sock) {
143 fprintf(stderr, "Failed to allocate netlink socket.\n");
147 nl_socket_disable_seq_check(iface_mon_sock);
149 nl_socket_modify_cb(iface_mon_sock, NL_CB_VALID, NL_CB_CUSTOM, iface_mon_handler, cb);
151 if (nl_connect(iface_mon_sock, NETLINK_ROUTE)) {
152 fprintf(stderr, "Failed to connect to generic netlink.\n");
154 goto out_handle_destroy;
157 nl_socket_add_membership(iface_mon_sock, RTNLGRP_LINK);
162 nl_socket_free(iface_mon_sock);
170 nl_socket_free(iface_mon_sock);
171 iface_mon_sock = NULL;
174 #elif defined(__APPLE__)
185 #include <sys/socket.h>
186 #include <sys/ioctl.h>
187 #include <sys/types.h>
189 #include <sys/kern_event.h>
194 static iface_mon_cb callback;
197 iface_mon_start(iface_mon_cb cb)
200 struct kev_request key;
202 /* Create a socket of type PF_SYSTEM to listen for events. */
203 s = socket(PF_SYSTEM, SOCK_RAW, SYSPROTO_EVENT);
208 * Ask for DLIL messages.
210 * XXX - also ask for KEV_INET_SUBCLASS and KEV_INET6_SUBCLASS,
211 * to detect new or changed network addresses, so those can be
212 * updated as well? Can we specify multiple filters on a socket,
213 * or must we specify KEV_ANY_SUBCLASS and filter the events after
216 key.vendor_code = KEV_VENDOR_APPLE;
217 key.kev_class = KEV_NETWORK_CLASS;
218 key.kev_subclass = KEV_DL_SUBCLASS;
219 if (ioctl(s, SIOCSKEVFILT, &key) == -1) {
236 iface_mon_get_sock(void)
242 * Size of buffer for kernel network event.
244 #define NET_EVENT_DATA_SIZE (KEV_MSG_HEADER_SIZE + sizeof (struct net_event_data))
247 iface_mon_event(void)
249 char msg[NET_EVENT_DATA_SIZE];
251 struct kern_event_msg *kem;
252 struct net_event_data *evd;
254 char ifr_name[IFNAMSIZ];
256 received = recv(s, msg, sizeof msg, 0);
258 /* Error - ignore. */
261 if ((size_t)received < sizeof msg) {
262 /* Short read - ignore. */
265 kem = (struct kern_event_msg *)msg;
266 evd_len = kem->total_size - KEV_MSG_HEADER_SIZE;
267 if (evd_len != sizeof (struct net_event_data)) {
268 /* Length of the message is bogus. */
271 evd = (struct net_event_data *)&kem->event_data[0];
272 g_snprintf(ifr_name, IFNAMSIZ, "%s%u", evd->if_name, evd->if_unit);
275 * Check type of event.
277 * Note: if we also ask for KEV_INET_SUBCLASS, we will get
281 * KEV_INET_CHANGED_ADDR
282 * KEV_INET_CHANGED_ADDR
283 * KEV_INET_SIFDSTADDR
284 * KEV_INET_SIFBRDADDR
285 * KEV_INET_SIFNETMASK
287 * reflecting network address changes, with the data being a
288 * struct kev_in_data rather than struct net_event_data, and
289 * if we also ask for KEV_INET6_SUBCLASS, we will get events
292 * KEV_INET6_NEW_LL_ADDR
293 * KEV_INET6_NEW_USER_ADDR
294 * KEV_INET6_NEW_RTADV_ADDR
295 * KEV_INET6_ADDR_DELETED
297 * with the data being a struct kev_in6_data.
299 switch (kem->event_code) {
301 case KEV_DL_IF_ATTACHED:
303 * A new interface has arrived.
305 * XXX - what we really want is "a new BPFable interface
306 * has arrived", but that's not available. While we're
307 * asking for additional help from BPF, it'd also be
308 * nice if we could ask it for a list of all interfaces
309 * that have had bpfattach()/bpf_attach() done on them,
310 * so we don't have to try to open the device in order
311 * to see whether we should show it as something on
312 * which we can capture.
314 callback(ifr_name, 1);
317 case KEV_DL_IF_DETACHED:
319 * An existing interface has been removed.
321 * XXX - use KEV_DL_IF_DETACHING instead, as that's
322 * called shortly after bpfdetach() is called, and
323 * bpfdetach() makes an interface no longer BPFable,
324 * and that's what we *really* care about.
326 callback(ifr_name, 0);
331 * Is there any reason to care about:
336 * KEV_DL_LINK_ADDRESS_CHANGED
337 * KEV_DL_IFCAP_CHANGED
339 * or any of the other events? On Snow Leopard and, I think,
340 * earlier releases, you can't attach a BPF device to an
341 * interface that's not up, so KEV_DL_SIFFLAGS might be
342 * worth listening to so that we only say "here's a new
343 * interface" when it goes up; on Lion (and possibly Mountain
344 * Lion), an interface doesn't have to be up in order to
345 * have a BPF device attached to it.
351 #else /* don't have something we support */
354 iface_mon_start(iface_mon_cb cb _U_)
365 iface_mon_get_sock(void)
371 iface_mon_event(void)
375 #endif /* HAVE_LIBNL */
377 #endif /* HAVE_LIBPCAP */