1 /* Copyright (c) 2008 The Board of Trustees of The Leland Stanford
4 * We are making the OpenFlow specification and associated documentation
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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
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24 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
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35 #include "vlog-socket.h"
43 #include <sys/socket.h>
45 #include <sys/types.h>
48 #include "fatal-signal.h"
49 #include "poll-loop.h"
50 #include "socket-util.h"
54 #ifndef SCM_CREDENTIALS
58 #define THIS_MODULE VLM_vlog_socket
61 /* Server for Vlog control connection. */
63 struct poll_waiter *waiter;
68 static void poll_server(int fd, short int events, void *server_);
70 /* Start listening for connections from clients and processing their
71 * requests. 'path' may be:
73 * - NULL, in which case the default socket path is used. (Only one
74 * Vlog_server_socket per process can use the default path.)
76 * - A name that does not start with '/', in which case it is appended to
77 * the default socket path.
79 * - An absolute path (starting with '/') that gives the exact name of
80 * the Unix domain socket to listen on.
82 * Returns 0 if successful, otherwise a positive errno value. If successful,
83 * sets '*serverp' to the new vlog_server, otherwise to NULL. */
85 vlog_server_listen(const char *path, struct vlog_server **serverp)
87 struct vlog_server *server = xmalloc(sizeof *server);
89 if (path && path[0] == '/') {
90 server->path = xstrdup(path);
92 server->path = xasprintf("/tmp/vlogs.%ld%s",
93 (long int) getpid(), path ? path : "");
96 server->fd = make_unix_socket(SOCK_DGRAM, true, true, server->path, NULL);
99 fprintf(stderr, "Could not initialize vlog configuration socket: %s\n",
100 strerror(-server->fd));
109 server->waiter = poll_fd_callback(server->fd, POLLIN, poll_server, server);
117 /* Destroys 'server' and stops listening for connections. */
119 vlog_server_close(struct vlog_server *server)
122 poll_cancel(server->waiter);
124 unlink(server->path);
125 fatal_signal_remove_file_to_unlink(server->path);
132 recv_with_creds(const struct vlog_server *server,
133 char *cmd_buf, size_t cmd_buf_size,
134 struct sockaddr_un *un, socklen_t *un_len)
136 #ifdef SCM_CREDENTIALS
137 /* Read a message and control messages from 'fd'. */
138 char cred_buf[CMSG_SPACE(sizeof(struct ucred))];
143 struct cmsghdr* cmsg;
145 iov.iov_base = cmd_buf;
146 iov.iov_len = cmd_buf_size - 1;
148 memset(&msg, 0, sizeof msg);
150 msg.msg_namelen = sizeof *un;
153 msg.msg_control = cred_buf;
154 msg.msg_controllen = sizeof cred_buf;
156 n = recvmsg(server->fd, &msg, 0);
157 *un_len = msg.msg_namelen;
163 /* Ensure that the message has credentials ensuring that it was sent
164 * from the same user who started us, or by root. */
166 for (cmsg = CMSG_FIRSTHDR(&msg); cmsg != NULL;
167 cmsg = CMSG_NXTHDR(&msg, cmsg)) {
168 if (cmsg->cmsg_level == SOL_SOCKET
169 && cmsg->cmsg_type == SCM_CREDENTIALS) {
170 cred = (struct ucred *) CMSG_DATA(cmsg);
171 } else if (cmsg->cmsg_level == SOL_SOCKET
172 && cmsg->cmsg_type == SCM_RIGHTS) {
173 /* Anyone can send us fds. If we don't close them, then that's
174 * a DoS: the sender can overflow our fd table. */
175 int* fds = (int *) CMSG_DATA(cmsg);
176 size_t n_fds = (cmsg->cmsg_len - CMSG_LEN(0)) / sizeof *fds;
178 for (i = 0; i < n_fds; i++) {
184 fprintf(stderr, "vlog: config message lacks credentials\n");
186 } else if (cred->uid && cred->uid != getuid()) {
187 fprintf(stderr, "vlog: config message uid=%ld is not 0 or %ld\n",
188 (long int) cred->uid, (long int) getuid());
193 #else /* !SCM_CREDENTIALS */
199 /* Receive a message. */
201 n = recvfrom(server->fd, cmd_buf, cmd_buf_size - 1, 0,
202 (struct sockaddr *) un, &len);
209 len -= offsetof(struct sockaddr_un, sun_path);
210 un->sun_path[len] = '\0';
211 if (stat(un->sun_path, &s) < 0) {
212 fprintf(stderr, "vlog: config message from inaccessible socket: %s\n",
216 if (!S_ISSOCK(s.st_mode)) {
217 fprintf(stderr, "vlog: config message not from a socket\n");
220 recent = time_now() - 30;
221 if (s.st_atime < recent || s.st_ctime < recent || s.st_mtime < recent) {
222 fprintf(stderr, "vlog: config socket too old\n");
225 if (s.st_uid && s.st_uid != getuid()) {
226 fprintf(stderr, "vlog: config message uid=%ld is not 0 or %ld\n",
227 (long int) s.st_uid, (long int) getuid());
231 #endif /* !SCM_CREDENTIALS */
234 /* Processes incoming requests for 'server'. */
236 poll_server(int fd UNUSED, short int events, void *server_)
238 struct vlog_server *server = server_;
241 struct sockaddr_un un;
246 error = recv_with_creds(server, cmd_buf, sizeof cmd_buf, &un, &un_len);
248 if (error != EAGAIN && error != EWOULDBLOCK) {
249 fprintf(stderr, "vlog: reading configuration socket: %s",
253 } else if (error < 0) {
257 /* Process message and send reply. */
258 if (!strncmp(cmd_buf, "set ", 4)) {
259 char *msg = vlog_set_levels_from_string(cmd_buf + 4);
260 reply = msg ? msg : xstrdup("ack");
261 } else if (!strcmp(cmd_buf, "list")) {
262 reply = vlog_get_levels();
263 } else if (!strcmp(cmd_buf, "reopen")) {
264 int error = vlog_reopen_log_file();
266 ? xasprintf("could not reopen log file \"%s\": %s",
267 vlog_get_log_file(), strerror(error))
270 reply = xstrdup("nak");
272 sendto(server->fd, reply, strlen(reply), 0,
273 (struct sockaddr*) &un, un_len);
276 server->waiter = poll_fd_callback(server->fd, POLLIN, poll_server, server);
279 /* Client for Vlog control connection. */
287 /* Connects to a Vlog server socket. 'path' may be:
289 * - A string that starts with a PID. If a non-null, non-absolute name
290 * was passed to Vlog_server_socket::listen(), then it must follow the
293 * - An absolute path (starting with '/') to a Vlog server socket or a
294 * pidfile. If it is a pidfile, the pidfile will be read and translated
295 * into a Vlog server socket file name.
297 * - A relative path, which is translated into a pidfile name and then
300 * Returns 0 if successful, otherwise a positive errno value. If successful,
301 * sets '*clientp' to the new vlog_client, otherwise to NULL. */
303 vlog_client_connect(const char *path, struct vlog_client **clientp)
306 struct vlog_client *client;
310 client = xmalloc(sizeof *client);
311 if (path[0] == '/') {
312 client->connect_path = xstrdup(path);
313 } else if (isdigit((unsigned char) path[0])) {
314 client->connect_path = xasprintf("/tmp/vlogs.%s", path);
316 client->connect_path = make_pidfile_name(path);
318 client->bind_path = NULL;
320 if (stat(client->connect_path, &s)) {
322 VLOG_WARN("could not stat \"%s\": %s",
323 client->connect_path, strerror(error));
325 } else if (S_ISREG(s.st_mode)) {
326 pid_t pid = read_pidfile(client->connect_path);
329 VLOG_WARN("could not read pidfile \"%s\": %s",
330 client->connect_path, strerror(error));
333 free(client->connect_path);
334 client->connect_path = xasprintf("/tmp/vlogs.%ld", (long int) pid);
336 client->bind_path = xasprintf("/tmp/vlog.%ld.%d",
337 (long int) getpid(), counter++);
338 client->fd = make_unix_socket(SOCK_DGRAM, false, false,
339 client->bind_path, client->connect_path);
340 if (client->fd < 0) {
348 free(client->connect_path);
349 free(client->bind_path);
355 /* Destroys 'client'. */
357 vlog_client_close(struct vlog_client *client)
360 unlink(client->bind_path);
361 fatal_signal_remove_file_to_unlink(client->bind_path);
362 free(client->bind_path);
363 free(client->connect_path);
369 /* Sends 'request' to the server socket that 'client' is connected to. Returns
370 * 0 if successful, otherwise a positive errno value. */
372 vlog_client_send(struct vlog_client *client, const char *request)
374 #ifdef SCM_CREDENTIALS
377 char buf[CMSG_SPACE(sizeof cred)];
379 struct cmsghdr* cmsg;
386 iov.iov_base = (void*) request;
387 iov.iov_len = strlen(request);
389 memset(&msg, 0, sizeof msg);
392 msg.msg_control = buf;
393 msg.msg_controllen = sizeof buf;
395 cmsg = CMSG_FIRSTHDR(&msg);
396 cmsg->cmsg_level = SOL_SOCKET;
397 cmsg->cmsg_type = SCM_CREDENTIALS;
398 cmsg->cmsg_len = CMSG_LEN(sizeof cred);
399 memcpy(CMSG_DATA(cmsg), &cred, sizeof cred);
400 msg.msg_controllen = cmsg->cmsg_len;
402 nbytes = sendmsg(client->fd, &msg, 0);
403 #else /* !SCM_CREDENTIALS */
404 ssize_t nbytes = send(client->fd, request, strlen(request), 0);
405 #endif /* !SCM_CREDENTIALS */
407 return nbytes == strlen(request) ? 0 : ENOBUFS;
413 /* Attempts to receive a response from the server socket that 'client' is
414 * connected to. Returns 0 if successful, otherwise a positive errno value.
415 * If successful, sets '*reply' to the reply, which the caller must free,
416 * otherwise to NULL. */
418 vlog_client_recv(struct vlog_client *client, char **reply)
429 nfds = time_poll(&pfd, 1, 1000);
432 } else if (nfds < 0) {
436 nbytes = read(client->fd, buffer, sizeof buffer - 1);
440 buffer[nbytes] = '\0';
441 *reply = xstrdup(buffer);
446 /* Sends 'request' to the server socket and waits for a reply. Returns 0 if
447 * successful, otherwise to a positive errno value. If successful, sets
448 * '*reply' to the reply, which the caller must free, otherwise to NULL. */
450 vlog_client_transact(struct vlog_client *client,
451 const char *request, char **reply)
455 /* Retry up to 3 times. */
456 for (i = 0; i < 3; ++i) {
457 int error = vlog_client_send(client, request);
462 error = vlog_client_recv(client, reply);
463 if (error != ETIMEDOUT) {
471 /* Returns the path of the server socket to which 'client' is connected. The
472 * caller must not modify or free the returned string. */
474 vlog_client_target(const struct vlog_client *client)
476 return client->connect_path;