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 "socket-util.h"
36 #include <arpa/inet.h>
44 #include <sys/resource.h>
47 #include "fatal-signal.h"
51 #define THIS_MODULE VLM_socket_util
53 /* Sets 'fd' to non-blocking mode. Returns 0 if successful, otherwise a
54 * positive errno value. */
56 set_nonblocking(int fd)
58 int flags = fcntl(fd, F_GETFL, 0);
60 if (fcntl(fd, F_SETFL, flags | O_NONBLOCK) != -1) {
63 VLOG_ERR("fcntl(F_SETFL) failed: %s", strerror(errno));
67 VLOG_ERR("fcntl(F_GETFL) failed: %s", strerror(errno));
72 /* Returns the maximum valid FD value, plus 1. */
76 static int max_fds = -1;
79 if (!getrlimit(RLIMIT_NOFILE, &r)
80 && r.rlim_cur != RLIM_INFINITY
81 && r.rlim_cur != RLIM_SAVED_MAX
82 && r.rlim_cur != RLIM_SAVED_CUR) {
85 VLOG_WARN("failed to obtain fd limit, defaulting to 1024");
92 /* Translates 'host_name', which may be a DNS name or an IP address, into a
93 * numeric IP address in '*addr'. Returns 0 if successful, otherwise a
94 * positive errno value. */
96 lookup_ip(const char *host_name, struct in_addr *addr)
98 if (!inet_aton(host_name, addr)) {
99 struct hostent *he = gethostbyname(host_name);
101 struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(1, 5);
102 VLOG_ERR_RL(&rl, "gethostbyname(%s): %s", host_name,
103 (h_errno == HOST_NOT_FOUND ? "host not found"
104 : h_errno == TRY_AGAIN ? "try again"
105 : h_errno == NO_RECOVERY ? "non-recoverable error"
106 : h_errno == NO_ADDRESS ? "no address"
110 addr->s_addr = *(uint32_t *) he->h_addr;
115 /* Returns the error condition associated with socket 'fd' and resets the
116 * socket's error status. */
118 get_socket_error(int fd)
121 socklen_t len = sizeof(error);
122 if (getsockopt(fd, SOL_SOCKET, SO_ERROR, &error, &len) < 0) {
123 struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(5, 10);
125 VLOG_ERR_RL(&rl, "getsockopt(SO_ERROR): %s", strerror(error));
131 check_connection_completion(int fd)
137 pfd.events = POLLOUT;
139 retval = poll(&pfd, 1, 0);
140 } while (retval < 0 && errno == EINTR);
142 return get_socket_error(fd);
143 } else if (retval < 0) {
144 static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(5, 10);
145 VLOG_ERR_RL(&rl, "poll: %s", strerror(errno));
152 /* Drain all the data currently in the receive queue of a datagram socket (and
153 * possibly additional data). There is no way to know how many packets are in
154 * the receive queue, but we do know that the total number of bytes queued does
155 * not exceed the receive buffer size, so we pull packets until none are left
156 * or we've read that many bytes. */
160 socklen_t rcvbuf_len;
163 rcvbuf_len = sizeof rcvbuf;
164 if (getsockopt(fd, SOL_SOCKET, SO_RCVBUF, &rcvbuf, &rcvbuf_len) < 0) {
165 static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(5, 10);
166 VLOG_ERR_RL(&rl, "getsockopt(SO_RCVBUF) failed: %s", strerror(errno));
170 /* In Linux, specifying MSG_TRUNC in the flags argument causes the
171 * datagram length to be returned, even if that is longer than the
172 * buffer provided. Thus, we can use a 1-byte buffer to discard the
173 * incoming datagram and still be able to account how many bytes were
174 * removed from the receive buffer.
176 * On other Unix-like OSes, MSG_TRUNC has no effect in the flags
179 #define BUFFER_SIZE 1
181 #define BUFFER_SIZE 2048
183 char buffer[BUFFER_SIZE];
184 ssize_t n_bytes = recv(fd, buffer, sizeof buffer,
185 MSG_TRUNC | MSG_DONTWAIT);
186 if (n_bytes <= 0 || n_bytes >= rcvbuf) {
194 /* Reads and discards up to 'n' datagrams from 'fd', stopping as soon as no
195 * more data can be immediately read. ('fd' should therefore be in
196 * non-blocking mode.)*/
198 drain_fd(int fd, size_t n_packets)
200 for (; n_packets > 0; n_packets--) {
201 /* 'buffer' only needs to be 1 byte long in most circumstances. This
202 * size is defensive against the possibility that we someday want to
203 * use a Linux tap device without TUN_NO_PI, in which case a buffer
204 * smaller than sizeof(struct tun_pi) will give EINVAL on read. */
206 if (read(fd, buffer, sizeof buffer) <= 0) {
212 /* Stores in '*un' a sockaddr_un that refers to file 'name'. Stores in
213 * '*un_len' the size of the sockaddr_un. */
215 make_sockaddr_un(const char *name, struct sockaddr_un* un, socklen_t *un_len)
217 un->sun_family = AF_UNIX;
218 strncpy(un->sun_path, name, sizeof un->sun_path);
219 un->sun_path[sizeof un->sun_path - 1] = '\0';
220 *un_len = (offsetof(struct sockaddr_un, sun_path)
221 + strlen (un->sun_path) + 1);
224 /* Creates a Unix domain socket in the given 'style' (either SOCK_DGRAM or
225 * SOCK_STREAM) that is bound to '*bind_path' (if 'bind_path' is non-null) and
226 * connected to '*connect_path' (if 'connect_path' is non-null). If 'nonblock'
227 * is true, the socket is made non-blocking. If 'passcred' is true, the socket
228 * is configured to receive SCM_CREDENTIALS control messages.
230 * Returns the socket's fd if successful, otherwise a negative errno value. */
232 make_unix_socket(int style, bool nonblock, bool passcred UNUSED,
233 const char *bind_path, const char *connect_path)
238 fd = socket(PF_UNIX, style, 0);
243 /* Set nonblocking mode right away, if we want it. This prevents blocking
244 * in connect(), if connect_path != NULL. (In turn, that's a corner case:
245 * it will only happen if style is SOCK_STREAM or SOCK_SEQPACKET, and only
246 * if a backlog of un-accepted connections has built up in the kernel.) */
248 int flags = fcntl(fd, F_GETFL, 0);
252 if (fcntl(fd, F_SETFL, flags | O_NONBLOCK) == -1) {
258 struct sockaddr_un un;
260 make_sockaddr_un(bind_path, &un, &un_len);
261 if (unlink(un.sun_path) && errno != ENOENT) {
262 VLOG_WARN("unlinking \"%s\": %s\n", un.sun_path, strerror(errno));
264 fatal_signal_add_file_to_unlink(bind_path);
265 if (bind(fd, (struct sockaddr*) &un, un_len)
266 || fchmod(fd, S_IRWXU)) {
272 struct sockaddr_un un;
274 make_sockaddr_un(connect_path, &un, &un_len);
275 if (connect(fd, (struct sockaddr*) &un, un_len)
276 && errno != EINPROGRESS) {
281 #ifdef SCM_CREDENTIALS
284 if (setsockopt(fd, SOL_SOCKET, SO_PASSCRED, &enable, sizeof(enable))) {
294 fatal_signal_remove_file_to_unlink(bind_path);
302 get_unix_name_len(socklen_t sun_len)
304 return (sun_len >= offsetof(struct sockaddr_un, sun_path)
305 ? sun_len - offsetof(struct sockaddr_un, sun_path)