1 | /* |
2 | * Copyright 6WIND S.A., 2014 |
3 | * |
4 | * This work is licensed under the terms of the GNU GPL, version 2 or |
5 | * (at your option) any later version. See the COPYING file in the |
6 | * top-level directory. |
7 | */ |
8 | |
9 | #include "qemu/osdep.h" |
10 | #include <sys/socket.h> |
11 | #include <sys/un.h> |
12 | |
13 | #include "qemu/queue.h" |
14 | |
15 | #include "ivshmem-client.h" |
16 | |
17 | /* log a message on stdout if verbose=1 */ |
18 | #define IVSHMEM_CLIENT_DEBUG(client, fmt, ...) do { \ |
19 | if ((client)->verbose) { \ |
20 | printf(fmt, ## __VA_ARGS__); \ |
21 | } \ |
22 | } while (0) |
23 | |
24 | /* read message from the unix socket */ |
25 | static int |
26 | ivshmem_client_read_one_msg(IvshmemClient *client, int64_t *index, int *fd) |
27 | { |
28 | int ret; |
29 | struct msghdr msg; |
30 | struct iovec iov[1]; |
31 | union { |
32 | struct cmsghdr cmsg; |
33 | char control[CMSG_SPACE(sizeof(int))]; |
34 | } msg_control; |
35 | struct cmsghdr *cmsg; |
36 | |
37 | iov[0].iov_base = index; |
38 | iov[0].iov_len = sizeof(*index); |
39 | |
40 | memset(&msg, 0, sizeof(msg)); |
41 | msg.msg_iov = iov; |
42 | msg.msg_iovlen = 1; |
43 | msg.msg_control = &msg_control; |
44 | msg.msg_controllen = sizeof(msg_control); |
45 | |
46 | ret = recvmsg(client->sock_fd, &msg, 0); |
47 | if (ret < sizeof(*index)) { |
48 | IVSHMEM_CLIENT_DEBUG(client, "cannot read message: %s\n" , |
49 | strerror(errno)); |
50 | return -1; |
51 | } |
52 | if (ret == 0) { |
53 | IVSHMEM_CLIENT_DEBUG(client, "lost connection to server\n" ); |
54 | return -1; |
55 | } |
56 | |
57 | *index = GINT64_FROM_LE(*index); |
58 | *fd = -1; |
59 | |
60 | for (cmsg = CMSG_FIRSTHDR(&msg); cmsg; cmsg = CMSG_NXTHDR(&msg, cmsg)) { |
61 | |
62 | if (cmsg->cmsg_len != CMSG_LEN(sizeof(int)) || |
63 | cmsg->cmsg_level != SOL_SOCKET || |
64 | cmsg->cmsg_type != SCM_RIGHTS) { |
65 | continue; |
66 | } |
67 | |
68 | memcpy(fd, CMSG_DATA(cmsg), sizeof(*fd)); |
69 | } |
70 | |
71 | return 0; |
72 | } |
73 | |
74 | /* free a peer when the server advertises a disconnection or when the |
75 | * client is freed */ |
76 | static void |
77 | ivshmem_client_free_peer(IvshmemClient *client, IvshmemClientPeer *peer) |
78 | { |
79 | unsigned vector; |
80 | |
81 | QTAILQ_REMOVE(&client->peer_list, peer, next); |
82 | for (vector = 0; vector < peer->vectors_count; vector++) { |
83 | close(peer->vectors[vector]); |
84 | } |
85 | |
86 | g_free(peer); |
87 | } |
88 | |
89 | /* handle message coming from server (new peer, new vectors) */ |
90 | static int |
91 | ivshmem_client_handle_server_msg(IvshmemClient *client) |
92 | { |
93 | IvshmemClientPeer *peer; |
94 | int64_t peer_id; |
95 | int ret, fd; |
96 | |
97 | ret = ivshmem_client_read_one_msg(client, &peer_id, &fd); |
98 | if (ret < 0) { |
99 | return -1; |
100 | } |
101 | |
102 | /* can return a peer or the local client */ |
103 | peer = ivshmem_client_search_peer(client, peer_id); |
104 | |
105 | /* delete peer */ |
106 | if (fd == -1) { |
107 | |
108 | if (peer == NULL || peer == &client->local) { |
109 | IVSHMEM_CLIENT_DEBUG(client, "receive delete for invalid " |
110 | "peer %" PRId64 "\n" , peer_id); |
111 | return -1; |
112 | } |
113 | |
114 | IVSHMEM_CLIENT_DEBUG(client, "delete peer id = %" PRId64 "\n" , peer_id); |
115 | ivshmem_client_free_peer(client, peer); |
116 | return 0; |
117 | } |
118 | |
119 | /* new peer */ |
120 | if (peer == NULL) { |
121 | peer = g_malloc0(sizeof(*peer)); |
122 | peer->id = peer_id; |
123 | peer->vectors_count = 0; |
124 | QTAILQ_INSERT_TAIL(&client->peer_list, peer, next); |
125 | IVSHMEM_CLIENT_DEBUG(client, "new peer id = %" PRId64 "\n" , peer_id); |
126 | } |
127 | |
128 | /* new vector */ |
129 | IVSHMEM_CLIENT_DEBUG(client, " new vector %d (fd=%d) for peer id %" |
130 | PRId64 "\n" , peer->vectors_count, fd, peer->id); |
131 | if (peer->vectors_count >= G_N_ELEMENTS(peer->vectors)) { |
132 | IVSHMEM_CLIENT_DEBUG(client, "Too many vectors received, failing" ); |
133 | return -1; |
134 | } |
135 | |
136 | peer->vectors[peer->vectors_count] = fd; |
137 | peer->vectors_count++; |
138 | |
139 | return 0; |
140 | } |
141 | |
142 | /* init a new ivshmem client */ |
143 | int |
144 | ivshmem_client_init(IvshmemClient *client, const char *unix_sock_path, |
145 | IvshmemClientNotifCb notif_cb, void *notif_arg, |
146 | bool verbose) |
147 | { |
148 | int ret; |
149 | unsigned i; |
150 | |
151 | memset(client, 0, sizeof(*client)); |
152 | |
153 | ret = snprintf(client->unix_sock_path, sizeof(client->unix_sock_path), |
154 | "%s" , unix_sock_path); |
155 | |
156 | if (ret < 0 || ret >= sizeof(client->unix_sock_path)) { |
157 | IVSHMEM_CLIENT_DEBUG(client, "could not copy unix socket path\n" ); |
158 | return -1; |
159 | } |
160 | |
161 | for (i = 0; i < IVSHMEM_CLIENT_MAX_VECTORS; i++) { |
162 | client->local.vectors[i] = -1; |
163 | } |
164 | |
165 | QTAILQ_INIT(&client->peer_list); |
166 | client->local.id = -1; |
167 | |
168 | client->notif_cb = notif_cb; |
169 | client->notif_arg = notif_arg; |
170 | client->verbose = verbose; |
171 | client->shm_fd = -1; |
172 | client->sock_fd = -1; |
173 | |
174 | return 0; |
175 | } |
176 | |
177 | /* create and connect to the unix socket */ |
178 | int |
179 | ivshmem_client_connect(IvshmemClient *client) |
180 | { |
181 | struct sockaddr_un sun; |
182 | int fd, ret; |
183 | int64_t tmp; |
184 | |
185 | IVSHMEM_CLIENT_DEBUG(client, "connect to client %s\n" , |
186 | client->unix_sock_path); |
187 | |
188 | client->sock_fd = socket(AF_UNIX, SOCK_STREAM, 0); |
189 | if (client->sock_fd < 0) { |
190 | IVSHMEM_CLIENT_DEBUG(client, "cannot create socket: %s\n" , |
191 | strerror(errno)); |
192 | return -1; |
193 | } |
194 | |
195 | sun.sun_family = AF_UNIX; |
196 | ret = snprintf(sun.sun_path, sizeof(sun.sun_path), "%s" , |
197 | client->unix_sock_path); |
198 | if (ret < 0 || ret >= sizeof(sun.sun_path)) { |
199 | IVSHMEM_CLIENT_DEBUG(client, "could not copy unix socket path\n" ); |
200 | goto err_close; |
201 | } |
202 | |
203 | if (connect(client->sock_fd, (struct sockaddr *)&sun, sizeof(sun)) < 0) { |
204 | IVSHMEM_CLIENT_DEBUG(client, "cannot connect to %s: %s\n" , sun.sun_path, |
205 | strerror(errno)); |
206 | goto err_close; |
207 | } |
208 | |
209 | /* first, we expect a protocol version */ |
210 | if (ivshmem_client_read_one_msg(client, &tmp, &fd) < 0 || |
211 | (tmp != IVSHMEM_PROTOCOL_VERSION) || fd != -1) { |
212 | IVSHMEM_CLIENT_DEBUG(client, "cannot read from server\n" ); |
213 | goto err_close; |
214 | } |
215 | |
216 | /* then, we expect our index + a fd == -1 */ |
217 | if (ivshmem_client_read_one_msg(client, &client->local.id, &fd) < 0 || |
218 | client->local.id < 0 || fd != -1) { |
219 | IVSHMEM_CLIENT_DEBUG(client, "cannot read from server (2)\n" ); |
220 | goto err_close; |
221 | } |
222 | IVSHMEM_CLIENT_DEBUG(client, "our_id=%" PRId64 "\n" , client->local.id); |
223 | |
224 | /* now, we expect shared mem fd + a -1 index, note that shm fd |
225 | * is not used */ |
226 | if (ivshmem_client_read_one_msg(client, &tmp, &fd) < 0 || |
227 | tmp != -1 || fd < 0) { |
228 | if (fd >= 0) { |
229 | close(fd); |
230 | } |
231 | IVSHMEM_CLIENT_DEBUG(client, "cannot read from server (3)\n" ); |
232 | goto err_close; |
233 | } |
234 | client->shm_fd = fd; |
235 | IVSHMEM_CLIENT_DEBUG(client, "shm_fd=%d\n" , fd); |
236 | |
237 | return 0; |
238 | |
239 | err_close: |
240 | close(client->sock_fd); |
241 | client->sock_fd = -1; |
242 | return -1; |
243 | } |
244 | |
245 | /* close connection to the server, and free all peer structures */ |
246 | void |
247 | ivshmem_client_close(IvshmemClient *client) |
248 | { |
249 | IvshmemClientPeer *peer; |
250 | unsigned i; |
251 | |
252 | IVSHMEM_CLIENT_DEBUG(client, "close client\n" ); |
253 | |
254 | while ((peer = QTAILQ_FIRST(&client->peer_list)) != NULL) { |
255 | ivshmem_client_free_peer(client, peer); |
256 | } |
257 | |
258 | close(client->shm_fd); |
259 | client->shm_fd = -1; |
260 | close(client->sock_fd); |
261 | client->sock_fd = -1; |
262 | client->local.id = -1; |
263 | for (i = 0; i < IVSHMEM_CLIENT_MAX_VECTORS; i++) { |
264 | close(client->local.vectors[i]); |
265 | client->local.vectors[i] = -1; |
266 | } |
267 | client->local.vectors_count = 0; |
268 | } |
269 | |
270 | /* get the fd_set according to the unix socket and peer list */ |
271 | void |
272 | ivshmem_client_get_fds(const IvshmemClient *client, fd_set *fds, int *maxfd) |
273 | { |
274 | int fd; |
275 | unsigned vector; |
276 | |
277 | FD_SET(client->sock_fd, fds); |
278 | if (client->sock_fd >= *maxfd) { |
279 | *maxfd = client->sock_fd + 1; |
280 | } |
281 | |
282 | for (vector = 0; vector < client->local.vectors_count; vector++) { |
283 | fd = client->local.vectors[vector]; |
284 | FD_SET(fd, fds); |
285 | if (fd >= *maxfd) { |
286 | *maxfd = fd + 1; |
287 | } |
288 | } |
289 | } |
290 | |
291 | /* handle events from eventfd: just print a message on notification */ |
292 | static int |
293 | ivshmem_client_handle_event(IvshmemClient *client, const fd_set *cur, int maxfd) |
294 | { |
295 | IvshmemClientPeer *peer; |
296 | uint64_t kick; |
297 | unsigned i; |
298 | int ret; |
299 | |
300 | peer = &client->local; |
301 | |
302 | for (i = 0; i < peer->vectors_count; i++) { |
303 | if (peer->vectors[i] >= maxfd || !FD_ISSET(peer->vectors[i], cur)) { |
304 | continue; |
305 | } |
306 | |
307 | ret = read(peer->vectors[i], &kick, sizeof(kick)); |
308 | if (ret < 0) { |
309 | return ret; |
310 | } |
311 | if (ret != sizeof(kick)) { |
312 | IVSHMEM_CLIENT_DEBUG(client, "invalid read size = %d\n" , ret); |
313 | errno = EINVAL; |
314 | return -1; |
315 | } |
316 | IVSHMEM_CLIENT_DEBUG(client, "received event on fd %d vector %d: %" |
317 | PRIu64 "\n" , peer->vectors[i], i, kick); |
318 | if (client->notif_cb != NULL) { |
319 | client->notif_cb(client, peer, i, client->notif_arg); |
320 | } |
321 | } |
322 | |
323 | return 0; |
324 | } |
325 | |
326 | /* read and handle new messages on the given fd_set */ |
327 | int |
328 | ivshmem_client_handle_fds(IvshmemClient *client, fd_set *fds, int maxfd) |
329 | { |
330 | if (client->sock_fd < maxfd && FD_ISSET(client->sock_fd, fds) && |
331 | ivshmem_client_handle_server_msg(client) < 0 && errno != EINTR) { |
332 | IVSHMEM_CLIENT_DEBUG(client, "ivshmem_client_handle_server_msg() " |
333 | "failed\n" ); |
334 | return -1; |
335 | } else if (ivshmem_client_handle_event(client, fds, maxfd) < 0 && |
336 | errno != EINTR) { |
337 | IVSHMEM_CLIENT_DEBUG(client, "ivshmem_client_handle_event() failed\n" ); |
338 | return -1; |
339 | } |
340 | |
341 | return 0; |
342 | } |
343 | |
344 | /* send a notification on a vector of a peer */ |
345 | int |
346 | ivshmem_client_notify(const IvshmemClient *client, |
347 | const IvshmemClientPeer *peer, unsigned vector) |
348 | { |
349 | uint64_t kick; |
350 | int fd; |
351 | |
352 | if (vector >= peer->vectors_count) { |
353 | IVSHMEM_CLIENT_DEBUG(client, "invalid vector %u on peer %" PRId64 "\n" , |
354 | vector, peer->id); |
355 | return -1; |
356 | } |
357 | fd = peer->vectors[vector]; |
358 | IVSHMEM_CLIENT_DEBUG(client, "notify peer %" PRId64 |
359 | " on vector %d, fd %d\n" , peer->id, vector, fd); |
360 | |
361 | kick = 1; |
362 | if (write(fd, &kick, sizeof(kick)) != sizeof(kick)) { |
363 | fprintf(stderr, "could not write to %d: %s\n" , peer->vectors[vector], |
364 | strerror(errno)); |
365 | return -1; |
366 | } |
367 | return 0; |
368 | } |
369 | |
370 | /* send a notification to all vectors of a peer */ |
371 | int |
372 | ivshmem_client_notify_all_vects(const IvshmemClient *client, |
373 | const IvshmemClientPeer *peer) |
374 | { |
375 | unsigned vector; |
376 | int ret = 0; |
377 | |
378 | for (vector = 0; vector < peer->vectors_count; vector++) { |
379 | if (ivshmem_client_notify(client, peer, vector) < 0) { |
380 | ret = -1; |
381 | } |
382 | } |
383 | |
384 | return ret; |
385 | } |
386 | |
387 | /* send a notification to all peers */ |
388 | int |
389 | ivshmem_client_notify_broadcast(const IvshmemClient *client) |
390 | { |
391 | IvshmemClientPeer *peer; |
392 | int ret = 0; |
393 | |
394 | QTAILQ_FOREACH(peer, &client->peer_list, next) { |
395 | if (ivshmem_client_notify_all_vects(client, peer) < 0) { |
396 | ret = -1; |
397 | } |
398 | } |
399 | |
400 | return ret; |
401 | } |
402 | |
403 | /* lookup peer from its id */ |
404 | IvshmemClientPeer * |
405 | ivshmem_client_search_peer(IvshmemClient *client, int64_t peer_id) |
406 | { |
407 | IvshmemClientPeer *peer; |
408 | |
409 | if (peer_id == client->local.id) { |
410 | return &client->local; |
411 | } |
412 | |
413 | QTAILQ_FOREACH(peer, &client->peer_list, next) { |
414 | if (peer->id == peer_id) { |
415 | return peer; |
416 | } |
417 | } |
418 | return NULL; |
419 | } |
420 | |
421 | /* dump our info, the list of peers their vectors on stdout */ |
422 | void |
423 | ivshmem_client_dump(const IvshmemClient *client) |
424 | { |
425 | const IvshmemClientPeer *peer; |
426 | unsigned vector; |
427 | |
428 | /* dump local infos */ |
429 | peer = &client->local; |
430 | printf("our_id = %" PRId64 "\n" , peer->id); |
431 | for (vector = 0; vector < peer->vectors_count; vector++) { |
432 | printf(" vector %d is enabled (fd=%d)\n" , vector, |
433 | peer->vectors[vector]); |
434 | } |
435 | |
436 | /* dump peers */ |
437 | QTAILQ_FOREACH(peer, &client->peer_list, next) { |
438 | printf("peer_id = %" PRId64 "\n" , peer->id); |
439 | |
440 | for (vector = 0; vector < peer->vectors_count; vector++) { |
441 | printf(" vector %d is enabled (fd=%d)\n" , vector, |
442 | peer->vectors[vector]); |
443 | } |
444 | } |
445 | } |
446 | |