1/*
2 * WPA Supplicant - Layer2 packet handling with privilege separation
3 * Copyright (c) 2007, Jouni Malinen <j@w1.fi>
4 *
5 * This software may be distributed under the terms of the BSD license.
6 * See README for more details.
7 */
8
9#include "includes.h"
10#include <sys/un.h>
11
12#include "common.h"
13#include "eloop.h"
14#include "l2_packet.h"
15#include "common/privsep_commands.h"
16
17
18struct l2_packet_data {
19	int fd; /* UNIX domain socket for privsep access */
20	void (*rx_callback)(void *ctx, const u8 *src_addr,
21			    const u8 *buf, size_t len);
22	void *rx_callback_ctx;
23	u8 own_addr[ETH_ALEN];
24	char *own_socket_path;
25	struct sockaddr_un priv_addr;
26};
27
28
29static int wpa_priv_cmd(struct l2_packet_data *l2, int cmd,
30			const void *data, size_t data_len)
31{
32	struct msghdr msg;
33	struct iovec io[2];
34
35	io[0].iov_base = &cmd;
36	io[0].iov_len = sizeof(cmd);
37	io[1].iov_base = (u8 *) data;
38	io[1].iov_len = data_len;
39
40	os_memset(&msg, 0, sizeof(msg));
41	msg.msg_iov = io;
42	msg.msg_iovlen = data ? 2 : 1;
43	msg.msg_name = &l2->priv_addr;
44	msg.msg_namelen = sizeof(l2->priv_addr);
45
46	if (sendmsg(l2->fd, &msg, 0) < 0) {
47		wpa_printf(MSG_ERROR, "L2: sendmsg(cmd): %s", strerror(errno));
48		return -1;
49	}
50
51	return 0;
52}
53
54
55int l2_packet_get_own_addr(struct l2_packet_data *l2, u8 *addr)
56{
57	os_memcpy(addr, l2->own_addr, ETH_ALEN);
58	return 0;
59}
60
61
62int l2_packet_send(struct l2_packet_data *l2, const u8 *dst_addr, u16 proto,
63		   const u8 *buf, size_t len)
64{
65	struct msghdr msg;
66	struct iovec io[4];
67	int cmd = PRIVSEP_CMD_L2_SEND;
68
69	io[0].iov_base = &cmd;
70	io[0].iov_len = sizeof(cmd);
71	io[1].iov_base = &dst_addr;
72	io[1].iov_len = ETH_ALEN;
73	io[2].iov_base = &proto;
74	io[2].iov_len = 2;
75	io[3].iov_base = (u8 *) buf;
76	io[3].iov_len = len;
77
78	os_memset(&msg, 0, sizeof(msg));
79	msg.msg_iov = io;
80	msg.msg_iovlen = 4;
81	msg.msg_name = &l2->priv_addr;
82	msg.msg_namelen = sizeof(l2->priv_addr);
83
84	if (sendmsg(l2->fd, &msg, 0) < 0) {
85		wpa_printf(MSG_ERROR, "L2: sendmsg(packet_send): %s",
86			   strerror(errno));
87		return -1;
88	}
89
90	return 0;
91}
92
93
94static void l2_packet_receive(int sock, void *eloop_ctx, void *sock_ctx)
95{
96	struct l2_packet_data *l2 = eloop_ctx;
97	u8 buf[2300];
98	int res;
99	struct sockaddr_un from;
100	socklen_t fromlen = sizeof(from);
101
102	os_memset(&from, 0, sizeof(from));
103	res = recvfrom(sock, buf, sizeof(buf), 0, (struct sockaddr *) &from,
104		       &fromlen);
105	if (res < 0) {
106		wpa_printf(MSG_ERROR, "l2_packet_receive - recvfrom: %s",
107			   strerror(errno));
108		return;
109	}
110	if (res < ETH_ALEN) {
111		wpa_printf(MSG_DEBUG, "L2: Too show packet received");
112		return;
113	}
114
115	if (from.sun_family != AF_UNIX ||
116	    os_strncmp(from.sun_path, l2->priv_addr.sun_path,
117		       sizeof(from.sun_path)) != 0) {
118		wpa_printf(MSG_DEBUG, "L2: Received message from unexpected "
119			   "source");
120		return;
121	}
122
123	l2->rx_callback(l2->rx_callback_ctx, buf, buf + ETH_ALEN,
124			res - ETH_ALEN);
125}
126
127
128struct l2_packet_data * l2_packet_init(
129	const char *ifname, const u8 *own_addr, unsigned short protocol,
130	void (*rx_callback)(void *ctx, const u8 *src_addr,
131			    const u8 *buf, size_t len),
132	void *rx_callback_ctx, int l2_hdr)
133{
134	struct l2_packet_data *l2;
135	char *own_dir = "/tmp";
136	char *priv_dir = "/var/run/wpa_priv";
137	size_t len;
138	static unsigned int counter = 0;
139	struct sockaddr_un addr;
140	fd_set rfds;
141	struct timeval tv;
142	int res;
143	u8 reply[ETH_ALEN + 1];
144	int reg_cmd[2];
145
146	l2 = os_zalloc(sizeof(struct l2_packet_data));
147	if (l2 == NULL)
148		return NULL;
149	l2->rx_callback = rx_callback;
150	l2->rx_callback_ctx = rx_callback_ctx;
151
152	len = os_strlen(own_dir) + 50;
153	l2->own_socket_path = os_malloc(len);
154	if (l2->own_socket_path == NULL) {
155		os_free(l2);
156		return NULL;
157	}
158	os_snprintf(l2->own_socket_path, len, "%s/wpa_privsep-l2-%d-%d",
159		    own_dir, getpid(), counter++);
160
161	l2->priv_addr.sun_family = AF_UNIX;
162	os_snprintf(l2->priv_addr.sun_path, sizeof(l2->priv_addr.sun_path),
163		    "%s/%s", priv_dir, ifname);
164
165	l2->fd = socket(PF_UNIX, SOCK_DGRAM, 0);
166	if (l2->fd < 0) {
167		wpa_printf(MSG_ERROR, "socket(PF_UNIX): %s", strerror(errno));
168		os_free(l2->own_socket_path);
169		l2->own_socket_path = NULL;
170		os_free(l2);
171		return NULL;
172	}
173
174	os_memset(&addr, 0, sizeof(addr));
175	addr.sun_family = AF_UNIX;
176	os_strlcpy(addr.sun_path, l2->own_socket_path, sizeof(addr.sun_path));
177	if (bind(l2->fd, (struct sockaddr *) &addr, sizeof(addr)) < 0) {
178		wpa_printf(MSG_ERROR, "l2-pkt-privsep: bind(PF_UNIX): %s",
179			   strerror(errno));
180		goto fail;
181	}
182
183	reg_cmd[0] = protocol;
184	reg_cmd[1] = l2_hdr;
185	if (wpa_priv_cmd(l2, PRIVSEP_CMD_L2_REGISTER, reg_cmd, sizeof(reg_cmd))
186	    < 0) {
187		wpa_printf(MSG_ERROR, "L2: Failed to register with wpa_priv");
188		goto fail;
189	}
190
191	FD_ZERO(&rfds);
192	FD_SET(l2->fd, &rfds);
193	tv.tv_sec = 5;
194	tv.tv_usec = 0;
195	res = select(l2->fd + 1, &rfds, NULL, NULL, &tv);
196	if (res < 0 && errno != EINTR) {
197		wpa_printf(MSG_ERROR, "select: %s", strerror(errno));
198		goto fail;
199	}
200
201	if (FD_ISSET(l2->fd, &rfds)) {
202		res = recv(l2->fd, reply, sizeof(reply), 0);
203		if (res < 0) {
204			wpa_printf(MSG_ERROR, "recv: %s", strerror(errno));
205			goto fail;
206		}
207	} else {
208		wpa_printf(MSG_DEBUG, "L2: Timeout while waiting for "
209			   "registration reply");
210		goto fail;
211	}
212
213	if (res != ETH_ALEN) {
214		wpa_printf(MSG_DEBUG, "L2: Unexpected registration reply "
215			   "(len=%d)", res);
216	}
217	os_memcpy(l2->own_addr, reply, ETH_ALEN);
218
219	eloop_register_read_sock(l2->fd, l2_packet_receive, l2, NULL);
220
221	return l2;
222
223fail:
224	close(l2->fd);
225	l2->fd = -1;
226	unlink(l2->own_socket_path);
227	os_free(l2->own_socket_path);
228	l2->own_socket_path = NULL;
229	os_free(l2);
230	return NULL;
231}
232
233
234struct l2_packet_data * l2_packet_init_bridge(
235	const char *br_ifname, const char *ifname, const u8 *own_addr,
236	unsigned short protocol,
237	void (*rx_callback)(void *ctx, const u8 *src_addr,
238			    const u8 *buf, size_t len),
239	void *rx_callback_ctx, int l2_hdr)
240{
241	return l2_packet_init(br_ifname, own_addr, protocol, rx_callback,
242			      rx_callback_ctx, l2_hdr);
243}
244
245
246void l2_packet_deinit(struct l2_packet_data *l2)
247{
248	if (l2 == NULL)
249		return;
250
251	if (l2->fd >= 0) {
252		wpa_priv_cmd(l2, PRIVSEP_CMD_L2_UNREGISTER, NULL, 0);
253		eloop_unregister_read_sock(l2->fd);
254		close(l2->fd);
255	}
256
257	if (l2->own_socket_path) {
258		unlink(l2->own_socket_path);
259		os_free(l2->own_socket_path);
260	}
261
262	os_free(l2);
263}
264
265
266int l2_packet_get_ip_addr(struct l2_packet_data *l2, char *buf, size_t len)
267{
268	/* TODO */
269	return -1;
270}
271
272
273void l2_packet_notify_auth_start(struct l2_packet_data *l2)
274{
275	wpa_priv_cmd(l2, PRIVSEP_CMD_L2_NOTIFY_AUTH_START, NULL, 0);
276}
277
278
279int l2_packet_set_packet_filter(struct l2_packet_data *l2,
280				enum l2_packet_filter_type type)
281{
282	return -1;
283}
284