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>
46 #include "fatal-signal.h"
50 #define THIS_MODULE VLM_socket_util
52 /* Sets 'fd' to non-blocking mode. Returns 0 if successful, otherwise a
53 * positive errno value. */
55 set_nonblocking(int fd)
57 int flags = fcntl(fd, F_GETFL, 0);
59 if (fcntl(fd, F_SETFL, flags | O_NONBLOCK) != -1) {
62 VLOG_ERR("fcntl(F_SETFL) failed: %s", strerror(errno));
66 VLOG_ERR("fcntl(F_GETFL) failed: %s", strerror(errno));
71 /* Translates 'host_name', which may be a DNS name or an IP address, into a
72 * numeric IP address in '*addr'. Returns 0 if successful, otherwise a
73 * positive errno value. */
75 lookup_ip(const char *host_name, struct in_addr *addr)
77 if (!inet_aton(host_name, addr)) {
78 struct hostent *he = gethostbyname(host_name);
80 struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(1, 5);
81 VLOG_ERR_RL(&rl, "gethostbyname(%s): %s", host_name,
82 (h_errno == HOST_NOT_FOUND ? "host not found"
83 : h_errno == TRY_AGAIN ? "try again"
84 : h_errno == NO_RECOVERY ? "non-recoverable error"
85 : h_errno == NO_ADDRESS ? "no address"
89 addr->s_addr = *(uint32_t *) he->h_addr;
94 /* Returns the error condition associated with socket 'fd' and resets the
95 * socket's error status. */
97 get_socket_error(int fd)
100 socklen_t len = sizeof(error);
101 if (getsockopt(fd, SOL_SOCKET, SO_ERROR, &error, &len) < 0) {
102 struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(5, 10);
104 VLOG_ERR_RL(&rl, "getsockopt(SO_ERROR): %s", strerror(error));
110 check_connection_completion(int fd)
116 pfd.events = POLLOUT;
118 retval = poll(&pfd, 1, 0);
119 } while (retval < 0 && errno == EINTR);
121 return get_socket_error(fd);
122 } else if (retval < 0) {
123 static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(5, 10);
124 VLOG_ERR_RL(&rl, "poll: %s", strerror(errno));
131 /* Drain all the data currently in the receive queue of a datagram socket (and
132 * possibly additional data). There is no way to know how many packets are in
133 * the receive queue, but we do know that the total number of bytes queued does
134 * not exceed the receive buffer size, so we pull packets until none are left
135 * or we've read that many bytes. */
139 socklen_t rcvbuf_len;
142 rcvbuf_len = sizeof rcvbuf;
143 if (getsockopt(fd, SOL_SOCKET, SO_RCVBUF, &rcvbuf, &rcvbuf_len) < 0) {
144 static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(5, 10);
145 VLOG_ERR_RL(&rl, "getsockopt(SO_RCVBUF) failed: %s", strerror(errno));
149 /* In Linux, specifying MSG_TRUNC in the flags argument causes the
150 * datagram length to be returned, even if that is longer than the
151 * buffer provided. Thus, we can use a 1-byte buffer to discard the
152 * incoming datagram and still be able to account how many bytes were
153 * removed from the receive buffer.
155 * On other Unix-like OSes, MSG_TRUNC has no effect in the flags
158 #define BUFFER_SIZE 1
160 #define BUFFER_SIZE 2048
162 char buffer[BUFFER_SIZE];
163 ssize_t n_bytes = recv(fd, buffer, sizeof buffer,
164 MSG_TRUNC | MSG_DONTWAIT);
165 if (n_bytes <= 0 || n_bytes >= rcvbuf) {
173 /* Stores in '*un' a sockaddr_un that refers to file 'name'. Stores in
174 * '*un_len' the size of the sockaddr_un. */
176 make_sockaddr_un(const char *name, struct sockaddr_un* un, socklen_t *un_len)
178 un->sun_family = AF_UNIX;
179 strncpy(un->sun_path, name, sizeof un->sun_path);
180 un->sun_path[sizeof un->sun_path - 1] = '\0';
181 *un_len = (offsetof(struct sockaddr_un, sun_path)
182 + strlen (un->sun_path) + 1);
185 /* Creates a Unix domain socket in the given 'style' (either SOCK_DGRAM or
186 * SOCK_STREAM) that is bound to '*bind_path' (if 'bind_path' is non-null) and
187 * connected to '*connect_path' (if 'connect_path' is non-null). If 'nonblock'
188 * is true, the socket is made non-blocking. If 'passcred' is true, the socket
189 * is configured to receive SCM_CREDENTIALS control messages.
191 * Returns the socket's fd if successful, otherwise a negative errno value. */
193 make_unix_socket(int style, bool nonblock, bool passcred UNUSED,
194 const char *bind_path, const char *connect_path)
199 fd = socket(PF_UNIX, style, 0);
204 /* Set nonblocking mode right away, if we want it. This prevents blocking
205 * in connect(), if connect_path != NULL. (In turn, that's a corner case:
206 * it will only happen if style is SOCK_STREAM or SOCK_SEQPACKET, and only
207 * if a backlog of un-accepted connections has built up in the kernel.) */
209 int flags = fcntl(fd, F_GETFL, 0);
213 if (fcntl(fd, F_SETFL, flags | O_NONBLOCK) == -1) {
219 struct sockaddr_un un;
221 make_sockaddr_un(bind_path, &un, &un_len);
222 if (unlink(un.sun_path) && errno != ENOENT) {
223 VLOG_WARN("unlinking \"%s\": %s\n", un.sun_path, strerror(errno));
225 fatal_signal_add_file_to_unlink(bind_path);
226 if (bind(fd, (struct sockaddr*) &un, un_len)
227 || fchmod(fd, S_IRWXU)) {
233 struct sockaddr_un un;
235 make_sockaddr_un(connect_path, &un, &un_len);
236 if (connect(fd, (struct sockaddr*) &un, un_len)
237 && errno != EINPROGRESS) {
242 #ifdef SCM_CREDENTIALS
245 if (setsockopt(fd, SOL_SOCKET, SO_PASSCRED, &enable, sizeof(enable))) {
255 fatal_signal_remove_file_to_unlink(bind_path);
263 get_unix_name_len(socklen_t sun_len)
265 return (sun_len >= offsetof(struct sockaddr_un, sun_path)
266 ? sun_len - offsetof(struct sockaddr_un, sun_path)