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,
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22 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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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"
48 #include "socket-util.h"
52 #ifndef SCM_CREDENTIALS
56 /* Server for Vlog control connection. */
58 struct poll_waiter *waiter;
63 static void poll_server(int fd, short int events, void *server_);
65 /* Start listening for connections from clients and processing their
66 * requests. 'path' may be:
68 * - NULL, in which case the default socket path is used. (Only one
69 * Vlog_server_socket per process can use the default path.)
71 * - A name that does not start with '/', in which case it is appended to
72 * the default socket path.
74 * - An absolute path (starting with '/') that gives the exact name of
75 * the Unix domain socket to listen on.
77 * Returns 0 if successful, otherwise a positive errno value. If successful,
78 * sets '*serverp' to the new vlog_server, otherwise to NULL. */
80 vlog_server_listen(const char *path, struct vlog_server **serverp)
82 struct vlog_server *server = xmalloc(sizeof *server);
84 if (path && path[0] == '/') {
85 server->path = xstrdup(path);
87 server->path = xasprintf("/tmp/vlogs.%ld%s",
88 (long int) getpid(), path ? path : "");
91 server->fd = make_unix_socket(SOCK_DGRAM, true, true, server->path, NULL);
96 fprintf(stderr, "Could not initialize vlog configuration socket: %s\n",
97 strerror(-server->fd));
104 server->waiter = poll_fd_callback(server->fd, POLLIN, poll_server, server);
112 /* Destroys 'server' and stops listening for connections. */
114 vlog_server_close(struct vlog_server *server)
117 poll_cancel(server->waiter);
119 unlink(server->path);
120 fatal_signal_remove_file_to_unlink(server->path);
127 recv_with_creds(const struct vlog_server *server,
128 char *cmd_buf, size_t cmd_buf_size,
129 struct sockaddr_un *un, socklen_t *un_len)
131 #ifdef SCM_CREDENTIALS
132 /* Read a message and control messages from 'fd'. */
133 char cred_buf[CMSG_SPACE(sizeof(struct ucred))];
138 struct cmsghdr* cmsg;
140 iov.iov_base = cmd_buf;
141 iov.iov_len = cmd_buf_size - 1;
143 memset(&msg, 0, sizeof msg);
145 msg.msg_namelen = sizeof *un;
148 msg.msg_control = cred_buf;
149 msg.msg_controllen = sizeof cred_buf;
151 n = recvmsg(server->fd, &msg, 0);
152 *un_len = msg.msg_namelen;
158 /* Ensure that the message has credentials ensuring that it was sent
159 * from the same user who started us, or by root. */
161 for (cmsg = CMSG_FIRSTHDR(&msg); cmsg != NULL;
162 cmsg = CMSG_NXTHDR(&msg, cmsg)) {
163 if (cmsg->cmsg_level == SOL_SOCKET
164 && cmsg->cmsg_type == SCM_CREDENTIALS) {
165 cred = (struct ucred *) CMSG_DATA(cmsg);
166 } else if (cmsg->cmsg_level == SOL_SOCKET
167 && cmsg->cmsg_type == SCM_RIGHTS) {
168 /* Anyone can send us fds. If we don't close them, then that's
169 * a DoS: the sender can overflow our fd table. */
170 int* fds = (int *) CMSG_DATA(cmsg);
171 size_t n_fds = (cmsg->cmsg_len - CMSG_LEN(0)) / sizeof *fds;
173 for (i = 0; i < n_fds; i++) {
179 fprintf(stderr, "vlog: config message lacks credentials\n");
181 } else if (cred->uid && cred->uid != getuid()) {
182 fprintf(stderr, "vlog: config message uid=%ld is not 0 or %ld\n",
183 (long int) cred->uid, (long int) getuid());
188 #else /* !SCM_CREDENTIALS */
194 /* Receive a message. */
196 n = recvfrom(server->fd, cmd_buf, cmd_buf_size - 1, 0,
197 (struct sockaddr *) un, &len);
204 len -= offsetof(struct sockaddr_un, sun_path);
205 un->sun_path[len] = '\0';
206 if (stat(un->sun_path, &s) < 0) {
207 fprintf(stderr, "vlog: config message from inaccessible socket: %s\n",
211 if (!S_ISSOCK(s.st_mode)) {
212 fprintf(stderr, "vlog: config message not from a socket\n");
215 recent = time_now() - 30;
216 if (s.st_atime < recent || s.st_ctime < recent || s.st_mtime < recent) {
217 fprintf(stderr, "vlog: config socket too old\n");
220 if (s.st_uid && s.st_uid != getuid()) {
221 fprintf(stderr, "vlog: config message uid=%ld is not 0 or %ld\n",
222 (long int) s.st_uid, (long int) getuid());
226 #endif /* !SCM_CREDENTIALS */
229 /* Processes incoming requests for 'server'. */
231 poll_server(int fd UNUSED, short int events, void *server_)
233 struct vlog_server *server = server_;
236 struct sockaddr_un un;
241 error = recv_with_creds(server, cmd_buf, sizeof cmd_buf, &un, &un_len);
243 if (error != EAGAIN && error != EWOULDBLOCK) {
244 fprintf(stderr, "vlog: reading configuration socket: %s",
248 } else if (error < 0) {
252 /* Process message and send reply. */
253 if (!strncmp(cmd_buf, "set ", 4)) {
254 char *msg = vlog_set_levels_from_string(cmd_buf + 4);
255 reply = msg ? msg : xstrdup("ack");
256 } else if (!strcmp(cmd_buf, "list")) {
257 reply = vlog_get_levels();
259 reply = xstrdup("nak");
261 sendto(server->fd, reply, strlen(reply), 0,
262 (struct sockaddr*) &un, un_len);
265 server->waiter = poll_fd_callback(server->fd, POLLIN, poll_server, server);
268 /* Client for Vlog control connection. */
276 /* Connects to a Vlog server socket. If 'path' does not start with '/', then
277 * it start with a PID as a string. If a non-null, non-absolute name was
278 * passed to Vlog_server_socket::listen(), then it must follow the PID in
279 * 'path'. If 'path' starts with '/', then it must be an absolute path that
280 * gives the exact name of the Unix domain socket to connect to.
282 * Returns 0 if successful, otherwise a positive errno value. If successful,
283 * sets '*clientp' to the new vlog_client, otherwise to NULL. */
285 vlog_client_connect(const char *path, struct vlog_client **clientp)
287 struct vlog_client *client;
290 client = xmalloc(sizeof *client);
291 client->connect_path = (path[0] == '/'
293 : xasprintf("/tmp/vlogs.%s", path));
295 client->bind_path = xasprintf("/tmp/vlog.%ld", (long int) getpid());
296 fd = make_unix_socket(SOCK_DGRAM, false, false,
297 client->bind_path, client->connect_path);
304 free(client->connect_path);
305 free(client->bind_path);
312 /* Destroys 'client'. */
314 vlog_client_close(struct vlog_client *client)
317 unlink(client->bind_path);
318 fatal_signal_remove_file_to_unlink(client->bind_path);
319 free(client->bind_path);
320 free(client->connect_path);
326 /* Sends 'request' to the server socket that 'client' is connected to. Returns
327 * 0 if successful, otherwise a positive errno value. */
329 vlog_client_send(struct vlog_client *client, const char *request)
331 #ifdef SCM_CREDENTIALS
334 char buf[CMSG_SPACE(sizeof cred)];
336 struct cmsghdr* cmsg;
343 iov.iov_base = (void*) request;
344 iov.iov_len = strlen(request);
346 memset(&msg, 0, sizeof msg);
349 msg.msg_control = buf;
350 msg.msg_controllen = sizeof buf;
352 cmsg = CMSG_FIRSTHDR(&msg);
353 cmsg->cmsg_level = SOL_SOCKET;
354 cmsg->cmsg_type = SCM_CREDENTIALS;
355 cmsg->cmsg_len = CMSG_LEN(sizeof cred);
356 memcpy(CMSG_DATA(cmsg), &cred, sizeof cred);
357 msg.msg_controllen = cmsg->cmsg_len;
359 nbytes = sendmsg(client->fd, &msg, 0);
360 #else /* !SCM_CREDENTIALS */
361 ssize_t nbytes = send(client->fd, request, strlen(request), 0);
362 #endif /* !SCM_CREDENTIALS */
364 return nbytes == strlen(request) ? 0 : ENOBUFS;
370 /* Attempts to receive a response from the server socket that 'client' is
371 * connected to. Returns 0 if successful, otherwise a positive errno value.
372 * If successful, sets '*reply' to the reply, which the caller must free,
373 * otherwise to NULL. */
375 vlog_client_recv(struct vlog_client *client, char **reply)
386 nfds = poll(&pfd, 1, 1000);
389 } else if (nfds < 0) {
393 nbytes = read(client->fd, buffer, sizeof buffer - 1);
397 buffer[nbytes] = '\0';
398 *reply = xstrdup(buffer);
403 /* Sends 'request' to the server socket and waits for a reply. Returns 0 if
404 * successful, otherwise to a positive errno value. If successful, sets
405 * '*reply' to the reply, which the caller must free, otherwise to NULL. */
407 vlog_client_transact(struct vlog_client *client,
408 const char *request, char **reply)
412 /* Retry up to 3 times. */
413 for (i = 0; i < 3; ++i) {
414 int error = vlog_client_send(client, request);
419 error = vlog_client_recv(client, reply);
420 if (error != ETIMEDOUT) {
428 /* Returns the path of the server socket to which 'client' is connected. The
429 * caller must not modify or free the returned string. */
431 vlog_client_target(const struct vlog_client *client)
433 return client->connect_path;