1 /* Copyright (c) 2008 The Board of Trustees of The Leland Stanford
4 * We are making the OpenFlow specification and associated documentation
5 * (Software) available for public use and benefit with the expectation
6 * that others will use, modify and enhance the Software and contribute
7 * those enhancements back to the community. However, since we would
8 * like to make the Software available for broadest use, with as few
9 * restrictions as possible permission is hereby granted, free of
10 * charge, to any person obtaining a copy of this Software to deal in
11 * the Software under the copyrights without restriction, including
12 * without limitation the rights to use, copy, modify, merge, publish,
13 * distribute, sublicense, and/or sell copies of the Software, and to
14 * permit persons to whom the Software is furnished to do so, subject to
15 * the following conditions:
17 * The above copyright notice and this permission notice shall be
18 * included in all copies or substantial portions of the Software.
20 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
21 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
22 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
23 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
24 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
25 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
26 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
29 * The name and trademarks of copyright holder(s) may NOT be used in
30 * advertising or publicity pertaining to the Software or any
31 * derivatives without specific, written prior permission.
35 #include "vlog-socket.h"
42 #include <sys/socket.h>
44 #include <sys/types.h>
46 #include "fatal-signal.h"
47 #include "poll-loop.h"
51 #ifndef SCM_CREDENTIALS
55 static int make_unix_socket(bool nonblock, bool passcred,
56 const char *bind_path, const char *connect_path);
58 /* Server for Vlog control connection. */
60 struct poll_waiter *waiter;
65 static void poll_server(int fd, short int events, void *server_);
67 /* Start listening for connections from clients and processing their
68 * requests. 'path' may be:
70 * - NULL, in which case the default socket path is used. (Only one
71 * Vlog_server_socket per process can use the default path.)
73 * - A name that does not start with '/', in which case it is appended to
74 * the default socket path.
76 * - An absolute path (starting with '/') that gives the exact name of
77 * the Unix domain socket to listen on.
79 * Returns 0 if successful, otherwise a positive errno value. If successful,
80 * sets '*serverp' to the new vlog_server, otherwise to NULL. */
82 vlog_server_listen(const char *path, struct vlog_server **serverp)
84 struct vlog_server *server = xmalloc(sizeof *server);
86 if (path && path[0] == '/') {
87 server->path = xstrdup(path);
89 server->path = xasprintf("/tmp/vlogs.%ld%s",
90 (long int) getpid(), path ? path : "");
93 server->fd = make_unix_socket(true, true, server->path, NULL);
98 fprintf(stderr, "Could not initialize vlog configuration socket: %s\n",
99 strerror(-server->fd));
106 server->waiter = poll_fd_callback(server->fd, POLLIN, poll_server, server);
114 /* Destroys 'server' and stops listening for connections. */
116 vlog_server_close(struct vlog_server *server)
119 poll_cancel(server->waiter);
121 unlink(server->path);
122 fatal_signal_remove_file_to_unlink(server->path);
129 recv_with_creds(const struct vlog_server *server,
130 char *cmd_buf, size_t cmd_buf_size,
131 struct sockaddr_un *un, socklen_t *un_len)
133 #ifdef SCM_CREDENTIALS
134 /* Read a message and control messages from 'fd'. */
135 char cred_buf[CMSG_SPACE(sizeof(struct ucred))];
140 struct cmsghdr* cmsg;
142 iov.iov_base = cmd_buf;
143 iov.iov_len = cmd_buf_size - 1;
145 memset(&msg, 0, sizeof msg);
147 msg.msg_namelen = sizeof *un;
150 msg.msg_control = cred_buf;
151 msg.msg_controllen = sizeof cred_buf;
153 n = recvmsg(server->fd, &msg, 0);
154 *un_len = msg.msg_namelen;
160 /* Ensure that the message has credentials ensuring that it was sent
161 * from the same user who started us, or by root. */
163 for (cmsg = CMSG_FIRSTHDR(&msg); cmsg != NULL;
164 cmsg = CMSG_NXTHDR(&msg, cmsg)) {
165 if (cmsg->cmsg_level == SOL_SOCKET
166 && cmsg->cmsg_type == SCM_CREDENTIALS) {
167 cred = (struct ucred *) CMSG_DATA(cmsg);
168 } else if (cmsg->cmsg_level == SOL_SOCKET
169 && cmsg->cmsg_type == SCM_RIGHTS) {
170 /* Anyone can send us fds. If we don't close them, then that's
171 * a DoS: the sender can overflow our fd table. */
172 int* fds = (int *) CMSG_DATA(cmsg);
173 size_t n_fds = (cmsg->cmsg_len - CMSG_LEN(0)) / sizeof *fds;
175 for (i = 0; i < n_fds; i++) {
181 fprintf(stderr, "vlog: config message lacks credentials\n");
183 } else if (cred->uid && cred->uid != getuid()) {
184 fprintf(stderr, "vlog: config message uid=%ld is not 0 or %ld\n",
185 (long int) cred->uid, (long int) getuid());
190 #else /* !SCM_CREDENTIALS */
196 /* Receive a message. */
198 n = recvfrom(server->fd, cmd_buf, cmd_buf_size - 1, 0,
199 (struct sockaddr *) un, &len);
206 len -= offsetof(struct sockaddr_un, sun_path);
207 un->sun_path[len] = '\0';
208 if (stat(un->sun_path, &s) < 0) {
209 fprintf(stderr, "vlog: config message from inaccessible socket: %s\n",
213 if (!S_ISSOCK(s.st_mode)) {
214 fprintf(stderr, "vlog: config message not from a socket\n");
217 recent = time(0) - 30;
218 if (s.st_atime < recent || s.st_ctime < recent || s.st_mtime < recent) {
219 fprintf(stderr, "vlog: config socket too old\n");
222 if (s.st_uid && s.st_uid != getuid()) {
223 fprintf(stderr, "vlog: config message uid=%ld is not 0 or %ld\n",
224 (long int) s.st_uid, (long int) getuid());
228 #endif /* !SCM_CREDENTIALS */
231 /* Processes incoming requests for 'server'. */
233 poll_server(int fd UNUSED, short int events, void *server_)
235 struct vlog_server *server = server_;
238 struct sockaddr_un un;
243 error = recv_with_creds(server, cmd_buf, sizeof cmd_buf, &un, &un_len);
245 if (error != EAGAIN && error != EWOULDBLOCK) {
246 fprintf(stderr, "vlog: reading configuration socket: %s",
250 } else if (error < 0) {
254 /* Process message and send reply. */
255 if (!strncmp(cmd_buf, "set ", 4)) {
256 char *msg = vlog_set_levels_from_string(cmd_buf + 4);
257 reply = msg ? msg : xstrdup("ack");
258 } else if (!strcmp(cmd_buf, "list")) {
259 reply = vlog_get_levels();
261 reply = xstrdup("nak");
263 sendto(server->fd, reply, strlen(reply), 0,
264 (struct sockaddr*) &un, un_len);
267 server->waiter = poll_fd_callback(server->fd, POLLIN, poll_server, server);
270 /* Client for Vlog control connection. */
278 /* Connects to a Vlog server socket. If 'path' does not start with '/', then
279 * it start with a PID as a string. If a non-null, non-absolute name was
280 * passed to Vlog_server_socket::listen(), then it must follow the PID in
281 * 'path'. If 'path' starts with '/', then it must be an absolute path that
282 * gives the exact name of the Unix domain socket to connect to.
284 * Returns 0 if successful, otherwise a positive errno value. If successful,
285 * sets '*clientp' to the new vlog_client, otherwise to NULL. */
287 vlog_client_connect(const char *path, struct vlog_client **clientp)
289 struct vlog_client *client;
292 client = xmalloc(sizeof *client);
293 client->connect_path = (path[0] == '/'
295 : xasprintf("/tmp/vlogs.%s", path));
297 client->bind_path = xasprintf("/tmp/vlog.%ld", (long int) getpid());
298 fd = make_unix_socket(false, false,
299 client->bind_path, client->connect_path);
306 free(client->connect_path);
307 free(client->bind_path);
314 /* Destroys 'client'. */
316 vlog_client_close(struct vlog_client *client)
319 unlink(client->bind_path);
320 fatal_signal_remove_file_to_unlink(client->bind_path);
321 free(client->bind_path);
322 free(client->connect_path);
328 /* Sends 'request' to the server socket that 'client' is connected to. Returns
329 * 0 if successful, otherwise a positive errno value. */
331 vlog_client_send(struct vlog_client *client, const char *request)
333 #ifdef SCM_CREDENTIALS
336 char buf[CMSG_SPACE(sizeof cred)];
338 struct cmsghdr* cmsg;
345 iov.iov_base = (void*) request;
346 iov.iov_len = strlen(request);
348 memset(&msg, 0, sizeof msg);
351 msg.msg_control = buf;
352 msg.msg_controllen = sizeof buf;
354 cmsg = CMSG_FIRSTHDR(&msg);
355 cmsg->cmsg_level = SOL_SOCKET;
356 cmsg->cmsg_type = SCM_CREDENTIALS;
357 cmsg->cmsg_len = CMSG_LEN(sizeof cred);
358 memcpy(CMSG_DATA(cmsg), &cred, sizeof cred);
359 msg.msg_controllen = cmsg->cmsg_len;
361 nbytes = sendmsg(client->fd, &msg, 0);
362 #else /* !SCM_CREDENTIALS */
363 ssize_t nbytes = send(client->fd, request, strlen(request), 0);
364 #endif /* !SCM_CREDENTIALS */
366 return nbytes == strlen(request) ? 0 : ENOBUFS;
372 /* Attempts to receive a response from the server socket that 'client' is
373 * connected to. Returns 0 if successful, otherwise a positive errno value.
374 * If successful, sets '*reply' to the reply, which the caller must free,
375 * otherwise to NULL. */
377 vlog_client_recv(struct vlog_client *client, char **reply)
388 nfds = poll(&pfd, 1, 1000);
391 } else if (nfds < 0) {
395 nbytes = read(client->fd, buffer, sizeof buffer - 1);
399 buffer[nbytes] = '\0';
400 *reply = xstrdup(buffer);
405 /* Sends 'request' to the server socket and waits for a reply. Returns 0 if
406 * successful, otherwise to a positive errno value. If successful, sets
407 * '*reply' to the reply, which the caller must free, otherwise to NULL. */
409 vlog_client_transact(struct vlog_client *client,
410 const char *request, char **reply)
414 /* Retry up to 3 times. */
415 for (i = 0; i < 3; ++i) {
416 int error = vlog_client_send(client, request);
421 error = vlog_client_recv(client, reply);
422 if (error != ETIMEDOUT) {
430 /* Returns the path of the server socket to which 'client' is connected. The
431 * caller must not modify or free the returned string. */
433 vlog_client_target(const struct vlog_client *client)
435 return client->connect_path;
438 /* Helper functions. */
440 /* Stores in '*un' a sockaddr_un that refers to file 'name'. Stores in
441 * '*un_len' the size of the sockaddr_un. */
443 make_sockaddr_un(const char *name, struct sockaddr_un* un, socklen_t *un_len)
445 un->sun_family = AF_UNIX;
446 strncpy(un->sun_path, name, sizeof un->sun_path);
447 un->sun_path[sizeof un->sun_path - 1] = '\0';
448 *un_len = (offsetof(struct sockaddr_un, sun_path)
449 + strlen (un->sun_path) + 1);
452 /* Creates a Unix domain datagram socket that is bound to '*bind_path' (if
453 * 'bind_path' is non-null) and connected to '*connect_path' (if 'connect_path'
454 * is non-null). If 'nonblock' is true, the socket is made non-blocking. If
455 * 'passcred' is true, the socket is configured to receive SCM_CREDENTIALS
458 * Returns the socket's fd if successful, otherwise a negative errno value. */
460 make_unix_socket(bool nonblock, bool passcred UNUSED,
461 const char *bind_path, const char *connect_path)
466 fd = socket(PF_UNIX, SOCK_DGRAM, 0);
472 int flags = fcntl(fd, F_GETFL, 0);
476 if (fcntl(fd, F_SETFL, flags | O_NONBLOCK) == -1) {
482 struct sockaddr_un un;
484 make_sockaddr_un(bind_path, &un, &un_len);
485 if (unlink(un.sun_path) && errno != ENOENT) {
486 fprintf(stderr, "unlinking \"%s\": %s\n",
487 un.sun_path, strerror(errno));
489 fatal_signal_add_file_to_unlink(bind_path);
490 if (bind(fd, (struct sockaddr*) &un, un_len)
491 || fchmod(fd, S_IRWXU)) {
497 struct sockaddr_un un;
499 make_sockaddr_un(connect_path, &un, &un_len);
500 if (connect(fd, (struct sockaddr*) &un, un_len)) {
505 #ifdef SCM_CREDENTIALS
508 if (setsockopt(fd, SOL_SOCKET, SO_PASSCRED, &enable, sizeof(enable))) {
518 fatal_signal_remove_file_to_unlink(bind_path);