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 }