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Sources/libubox/usock.c

  1 /*
  2  * usock - socket helper functions
  3  *
  4  * Copyright (C) 2010 Steven Barth <steven@midlink.org>
  5  * Copyright (C) 2011-2012 Felix Fietkau <nbd@openwrt.org>
  6  *
  7  * Permission to use, copy, modify, and/or distribute this software for any
  8  * purpose with or without fee is hereby granted, provided that the above
  9  * copyright notice and this permission notice appear in all copies.
 10  *
 11  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 12  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 13  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 14  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 15  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 16  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 17  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 18  */
 19 #include <sys/types.h>
 20 #include <sys/socket.h>
 21 #include <sys/un.h>
 22 #include <netdb.h>
 23 #include <poll.h>
 24 #include <stdlib.h>
 25 #include <unistd.h>
 26 #include <fcntl.h>
 27 #include <errno.h>
 28 #include <string.h>
 29 #include <stdbool.h>
 30 #include <stdio.h>
 31 #include <poll.h>
 32 
 33 #include "usock.h"
 34 #include "utils.h"
 35 
 36 static void usock_set_flags(int sock, unsigned int type)
 37 {
 38         if (!(type & USOCK_NOCLOEXEC))
 39                 fcntl(sock, F_SETFD, fcntl(sock, F_GETFD) | FD_CLOEXEC);
 40 
 41         if (type & USOCK_NONBLOCK)
 42                 fcntl(sock, F_SETFL, fcntl(sock, F_GETFL) | O_NONBLOCK);
 43 }
 44 
 45 static int usock_connect(int type, struct sockaddr *sa, int sa_len, int family, int socktype, bool server)
 46 {
 47         int sock;
 48 
 49         sock = socket(family, socktype, 0);
 50         if (sock < 0)
 51                 return -1;
 52 
 53         usock_set_flags(sock, type);
 54 
 55         if (server) {
 56                 const int one = 1;
 57                 setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one));
 58 
 59                 if (!bind(sock, sa, sa_len) &&
 60                     (socktype != SOCK_STREAM || !listen(sock, SOMAXCONN)))
 61                         return sock;
 62         } else {
 63                 if (!connect(sock, sa, sa_len) || errno == EINPROGRESS)
 64                         return sock;
 65         }
 66 
 67         close(sock);
 68         return -1;
 69 }
 70 
 71 static int usock_unix(int type, const char *host)
 72 {
 73         struct sockaddr_un sun = {.sun_family = AF_UNIX};
 74         bool server = !!(type & USOCK_SERVER);
 75         int socktype = ((type & 0xff) == USOCK_TCP) ? SOCK_STREAM : SOCK_DGRAM;
 76 
 77         if (strlen(host) >= sizeof(sun.sun_path)) {
 78                 errno = EINVAL;
 79                 return -1;
 80         }
 81         strcpy(sun.sun_path, host);
 82 
 83         return usock_connect(type, (struct sockaddr*)&sun, sizeof(sun), AF_UNIX, socktype, server);
 84 }
 85 
 86 static int
 87 usock_inet_notimeout(int type, struct addrinfo *result, void *addr)
 88 {
 89         struct addrinfo *rp;
 90         int socktype = ((type & 0xff) == USOCK_TCP) ? SOCK_STREAM : SOCK_DGRAM;
 91         bool server = !!(type & USOCK_SERVER);
 92         int sock;
 93 
 94         for (rp = result; rp != NULL; rp = rp->ai_next) {
 95                 sock = usock_connect(type, rp->ai_addr, rp->ai_addrlen, rp->ai_family, socktype, server);
 96                 if (sock >= 0) {
 97                         if (addr)
 98                                 memcpy(addr, rp->ai_addr, rp->ai_addrlen);
 99                         return sock;
100                 }
101         }
102 
103         return -1;
104 }
105 
106 static int poll_restart(struct pollfd *fds, int nfds, int timeout)
107 {
108         struct timespec ts, cur;
109         int msec = timeout % 1000;
110         int ret;
111 
112         clock_gettime(CLOCK_MONOTONIC, &ts);
113 
114         ts.tv_nsec += msec * 1000000;
115         if (ts.tv_nsec > 1000000000) {
116                 ts.tv_sec++;
117                 ts.tv_nsec -= 1000000000;
118         }
119         ts.tv_sec += timeout / 1000;
120 
121         while (1) {
122                 ret = poll(fds, nfds, timeout);
123                 if (ret == EAGAIN)
124                         continue;
125 
126                 if (ret != EINTR)
127                         return ret;
128 
129                 clock_gettime(CLOCK_MONOTONIC, &cur);
130                 timeout = (ts.tv_sec - cur.tv_sec) * 1000;
131                 timeout += (ts.tv_nsec - cur.tv_nsec) / 1000000;
132                 if (timeout <= 0)
133                         return 0;
134         }
135 }
136 
137 int usock_inet_timeout(int type, const char *host, const char *service,
138                        void *addr, int timeout)
139 {
140         int socktype = ((type & 0xff) == USOCK_TCP) ? SOCK_STREAM : SOCK_DGRAM;
141         bool server = !!(type & USOCK_SERVER);
142         struct addrinfo *result, *rp;
143         struct addrinfo hints = {
144                 .ai_family = (type & USOCK_IPV6ONLY) ? AF_INET6 :
145                         (type & USOCK_IPV4ONLY) ? AF_INET : AF_UNSPEC,
146                 .ai_socktype = socktype,
147                 .ai_flags = AI_ADDRCONFIG
148                         | ((type & USOCK_SERVER) ? AI_PASSIVE : 0)
149                         | ((type & USOCK_NUMERIC) ? AI_NUMERICHOST : 0),
150         };
151         struct addrinfo *rp_v6 = NULL;
152         struct addrinfo *rp_v4 = NULL;
153         struct pollfd pfds[2] = {
154             { .fd = -1, .events = POLLOUT },
155             { .fd = -1, .events = POLLOUT },
156         };
157         int sock = -1;
158         int i;
159 
160         if (getaddrinfo(host, service, &hints, &result))
161                 return -1;
162 
163         if (timeout <= 0 || server) {
164                 sock = usock_inet_notimeout(type, result, addr);
165                 goto free_addrinfo;
166         }
167 
168         for (rp = result; rp != NULL; rp = rp->ai_next) {
169                 if (rp->ai_family == AF_INET6 && !rp_v6)
170                         rp_v6 = rp;
171                 if (rp->ai_family == AF_INET && !rp_v4)
172                         rp_v4 = rp;
173         }
174 
175         if (!rp_v6 && !rp_v4)
176                 goto out;
177 
178         if (rp_v6) {
179                 rp = rp_v6;
180                 pfds[0].fd = usock_connect(type | USOCK_NONBLOCK, rp->ai_addr,
181                                            rp->ai_addrlen, rp->ai_family,
182                                            socktype, server);
183                 if (pfds[0].fd < 0) {
184                         rp_v6 = NULL;
185                         goto try_v4;
186                 }
187 
188                 if (timeout > 300) {
189                         if (poll_restart(pfds, 1, 300) == 1) {
190                                 rp = rp_v6;
191                                 sock = pfds[0].fd;
192                                 goto out;
193                         }
194                 }
195                 timeout -= 300;
196         }
197 
198 try_v4:
199         if (rp_v4) {
200                 rp = rp_v4;
201                 pfds[1].fd = usock_connect(type | USOCK_NONBLOCK, rp->ai_addr,
202                                                  rp->ai_addrlen, rp->ai_family,
203                                                  socktype, server);
204                 if (pfds[1].fd < 0) {
205                         rp_v4 = NULL;
206                         if (!rp_v6)
207                                 goto out;
208                         goto wait;
209                 }
210         }
211 
212 wait:
213         poll_restart(pfds + !rp_v6, !!rp_v6 + !!rp_v4, timeout);
214         if (pfds[0].revents & POLLOUT) {
215                 rp = rp_v6;
216                 sock = pfds[0].fd;
217                 goto out;
218         }
219 
220         if (pfds[1].revents & POLLOUT) {
221                 rp = rp_v4;
222                 sock = pfds[1].fd;
223                 goto out;
224         }
225 
226 out:
227         for (i = 0; i < 2; i++) {
228                 int fd = pfds[i].fd;
229                 if (fd >= 0 && fd != sock)
230                         close(fd);
231         }
232 
233         if (!(type & USOCK_NONBLOCK))
234                 fcntl(sock, F_SETFL, fcntl(sock, F_GETFL) & ~O_NONBLOCK);
235 
236         if (addr && sock >= 0)
237                 memcpy(addr, rp->ai_addr, rp->ai_addrlen);
238 free_addrinfo:
239         freeaddrinfo(result);
240         return sock;
241 }
242 
243 const char *usock_port(int port)
244 {
245         static char buffer[sizeof("65535\0")];
246 
247         if (port < 0 || port > 65535)
248                 return NULL;
249 
250         snprintf(buffer, sizeof(buffer), "%u", port);
251 
252         return buffer;
253 }
254 
255 int usock(int type, const char *host, const char *service) {
256         int sock;
257 
258         if (type & USOCK_UNIX)
259                 sock = usock_unix(type, host);
260         else
261                 sock = usock_inet(type, host, service, NULL);
262 
263         if (sock < 0)
264                 return -1;
265 
266         return sock;
267 }
268 
269 int usock_wait_ready(int fd, int msecs) {
270         struct pollfd fds[1];
271         int res;
272 
273         fds[0].fd = fd;
274         fds[0].events = POLLOUT;
275 
276         res = poll(fds, 1, msecs);
277         if (res < 0) {
278                 return errno;
279         } else if (res == 0) {
280                 return -ETIMEDOUT;
281         } else {
282                 int err = 0;
283                 socklen_t optlen = sizeof(err);
284 
285                 res = getsockopt(fd, SOL_SOCKET, SO_ERROR, &err, &optlen);
286                 if (res)
287                         return errno;
288                 if (err)
289                         return err;
290         }
291 
292         return 0;
293 }
294 

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