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 >= 0 || (errno != EINTR && errno != EAGAIN))
 124                         return ret;
 125
 126                 clock_gettime(CLOCK_MONOTONIC, &cur);
 127                 timeout = (ts.tv_sec - cur.tv_sec) * 1000;
 128                 timeout += (ts.tv_nsec - cur.tv_nsec) / 1000000;
 129                 if (timeout <= 0)
 130                         return 0;
 131         }
 132 }
 133
 134 int usock_inet_timeout(int type, const char *host, const char *service,
 135                        void *addr, int timeout)
 136 {
 137         int socktype = ((type & 0xff) == USOCK_TCP) ? SOCK_STREAM : SOCK_DGRAM;
 138         bool server = !!(type & USOCK_SERVER);
 139         struct addrinfo *result, *rp;
 140         struct addrinfo hints = {
 141                 .ai_family = (type & USOCK_IPV6ONLY) ? AF_INET6 :
 142                         (type & USOCK_IPV4ONLY) ? AF_INET : AF_UNSPEC,
 143                 .ai_socktype = socktype,
 144                 .ai_flags = AI_ADDRCONFIG
 145                         | ((type & USOCK_SERVER) ? AI_PASSIVE : 0)
 146                         | ((type & USOCK_NUMERIC) ? AI_NUMERICHOST : 0),
 147         };
 148         struct addrinfo *rp_v6 = NULL;
 149         struct addrinfo *rp_v4 = NULL;
 150         struct pollfd pfds[2] = {
 151             { .fd = -1, .events = POLLOUT },
 152             { .fd = -1, .events = POLLOUT },
 153         };
 154         int sock = -1;
 155         int i;
 156
 157         if (getaddrinfo(host, service, &hints, &result))
 158                 return -1;
 159
 160         if (timeout <= 0 || server) {
 161                 sock = usock_inet_notimeout(type, result, addr);
 162                 goto free_addrinfo;
 163         }
 164
 165         for (rp = result; rp != NULL; rp = rp->ai_next) {
 166                 if (rp->ai_family == AF_INET6 && !rp_v6)
 167                         rp_v6 = rp;
 168                 if (rp->ai_family == AF_INET && !rp_v4)
 169                         rp_v4 = rp;
 170         }
 171
 172         if (!rp_v6 && !rp_v4)
 173                 goto out;
 174
 175         if (rp_v6) {
 176                 rp = rp_v6;
 177                 pfds[0].fd = usock_connect(type | USOCK_NONBLOCK, rp->ai_addr,
 178                                            rp->ai_addrlen, rp->ai_family,
 179                                            socktype, server);
 180                 if (pfds[0].fd < 0) {
 181                         rp_v6 = NULL;
 182                         goto try_v4;
 183                 }
 184
 185                 if (timeout > 300) {
 186                         if (poll_restart(pfds, 1, 300) == 1) {
 187                                 rp = rp_v6;
 188                                 sock = pfds[0].fd;
 189                                 goto out;
 190                         }
 191                 }
 192                 timeout -= 300;
 193         }
 194
 195 try_v4:
 196         if (rp_v4) {
 197                 rp = rp_v4;
 198                 pfds[1].fd = usock_connect(type | USOCK_NONBLOCK, rp->ai_addr,
 199                                                  rp->ai_addrlen, rp->ai_family,
 200                                                  socktype, server);
 201                 if (pfds[1].fd < 0) {
 202                         rp_v4 = NULL;
 203                         if (!rp_v6)
 204                                 goto out;
 205                         goto wait;
 206                 }
 207         }
 208
 209 wait:
 210         poll_restart(pfds + !rp_v6, !!rp_v6 + !!rp_v4, timeout);
 211         if (pfds[0].revents & POLLOUT) {
 212                 rp = rp_v6;
 213                 sock = pfds[0].fd;
 214                 goto out;
 215         }
 216
 217         if (pfds[1].revents & POLLOUT) {
 218                 rp = rp_v4;
 219                 sock = pfds[1].fd;
 220                 goto out;
 221         }
 222
 223 out:
 224         for (i = 0; i < 2; i++) {
 225                 int fd = pfds[i].fd;
 226                 if (fd >= 0 && fd != sock)
 227                         close(fd);
 228         }
 229
 230         if (!(type & USOCK_NONBLOCK))
 231                 fcntl(sock, F_SETFL, fcntl(sock, F_GETFL) & ~O_NONBLOCK);
 232
 233         if (addr && sock >= 0)
 234                 memcpy(addr, rp->ai_addr, rp->ai_addrlen);
 235 free_addrinfo:
 236         freeaddrinfo(result);
 237         return sock;
 238 }
 239
 240 const char *usock_port(int port)
 241 {
 242         static char buffer[sizeof("65535\0")];
 243
 244         if (port < 0 || port > 65535)
 245                 return NULL;
 246
 247         snprintf(buffer, sizeof(buffer), "%u", port);
 248
 249         return buffer;
 250 }
 251
 252 int usock(int type, const char *host, const char *service) {
 253         int sock;
 254
 255         if (type & USOCK_UNIX)
 256                 sock = usock_unix(type, host);
 257         else
 258                 sock = usock_inet(type, host, service, NULL);
 259
 260         if (sock < 0)
 261                 return -1;
 262
 263         return sock;
 264 }
 265
 266 int usock_wait_ready(int fd, int msecs) {
 267         struct pollfd fds[1];
 268         int res;
 269
 270         fds[0].fd = fd;
 271         fds[0].events = POLLOUT;
 272
 273         res = poll(fds, 1, msecs);
 274         if (res < 0) {
 275                 return errno;
 276         } else if (res == 0) {
 277                 return -ETIMEDOUT;
 278         } else {
 279                 int err = 0;
 280                 socklen_t optlen = sizeof(err);
 281
 282                 res = getsockopt(fd, SOL_SOCKET, SO_ERROR, &err, &optlen);
 283                 if (res)
 284                         return errno;
 285                 if (err)
 286                         return err;
 287         }
 288
 289         return 0;
 290 }