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
  32 #include "usock.h"
  33
  34 static void usock_set_flags(int sock, unsigned int type)
  35 {
  36         if (!(type & USOCK_NOCLOEXEC))
  37                 fcntl(sock, F_SETFD, fcntl(sock, F_GETFD) | FD_CLOEXEC);
  38
  39         if (type & USOCK_NONBLOCK)
  40                 fcntl(sock, F_SETFL, fcntl(sock, F_GETFL) | O_NONBLOCK);
  41 }
  42
  43 static int usock_connect(int type, struct sockaddr *sa, int sa_len, int family, int socktype, bool server)
  44 {
  45         int sock;
  46
  47         sock = socket(family, socktype, 0);
  48         if (sock < 0)
  49                 return -1;
  50
  51         usock_set_flags(sock, type);
  52
  53         if (server) {
  54                 const int one = 1;
  55                 setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one));
  56
  57                 if (!bind(sock, sa, sa_len) &&
  58                     (socktype != SOCK_STREAM || !listen(sock, SOMAXCONN)))
  59                         return sock;
  60         } else {
  61                 if (!connect(sock, sa, sa_len) || errno == EINPROGRESS)
  62                         return sock;
  63         }
  64
  65         close(sock);
  66         return -1;
  67 }
  68
  69 static int usock_unix(int type, const char *host, int socktype, bool server)
  70 {
  71         struct sockaddr_un sun = {.sun_family = AF_UNIX};
  72
  73         if (strlen(host) >= sizeof(sun.sun_path)) {
  74                 errno = EINVAL;
  75                 return -1;
  76         }
  77         strcpy(sun.sun_path, host);
  78
  79         return usock_connect(type, (struct sockaddr*)&sun, sizeof(sun), AF_UNIX, socktype, server);
  80 }
  81
  82 static int usock_inet(int type, const char *host, const char *service, int socktype, bool server)
  83 {
  84         struct addrinfo *result, *rp;
  85         struct addrinfo hints = {
  86                 .ai_family = (type & USOCK_IPV6ONLY) ? AF_INET6 :
  87                         (type & USOCK_IPV4ONLY) ? AF_INET : AF_UNSPEC,
  88                 .ai_socktype = socktype,
  89                 .ai_flags = AI_ADDRCONFIG
  90                         | ((type & USOCK_SERVER) ? AI_PASSIVE : 0)
  91                         | ((type & USOCK_NUMERIC) ? AI_NUMERICHOST : 0),
  92         };
  93         int sock = -1;
  94
  95         if (getaddrinfo(host, service, &hints, &result))
  96                 return -1;
  97
  98         for (rp = result; rp != NULL; rp = rp->ai_next) {
  99                 sock = usock_connect(type, rp->ai_addr, rp->ai_addrlen, rp->ai_family, socktype, server);
 100                 if (sock >= 0)
 101                         break;
 102         }
 103
 104         freeaddrinfo(result);
 105         return sock;
 106 }
 107
 108 const char *usock_port(int port)
 109 {
 110         static char buffer[sizeof("65535\0")];
 111
 112         if (port < 0 || port > 65535)
 113                 return NULL;
 114
 115         snprintf(buffer, sizeof(buffer), "%u", port);
 116
 117         return buffer;
 118 }
 119
 120 int usock(int type, const char *host, const char *service) {
 121         int socktype = ((type & 0xff) == USOCK_TCP) ? SOCK_STREAM : SOCK_DGRAM;
 122         bool server = !!(type & USOCK_SERVER);
 123         int sock;
 124
 125         if (type & USOCK_UNIX)
 126                 sock = usock_unix(type, host, socktype, server);
 127         else
 128                 sock = usock_inet(type, host, service, socktype, server);
 129
 130         if (sock < 0)
 131                 return -1;
 132
 133         return sock;
 134 }
 135
 136 int usock_wait_ready(int fd, int msecs) {
 137         struct pollfd fds[1];
 138         int res;
 139
 140         fds[0].fd = fd;
 141         fds[0].events = POLLOUT;
 142
 143         res = poll(fds, 1, msecs);
 144         if (res < 0) {
 145                 return errno;
 146         } else if (res == 0) {
 147                 return -ETIMEDOUT;
 148         } else {
 149                 int err = 0;
 150                 socklen_t optlen = sizeof(err);
 151
 152                 res = getsockopt(fd, SOL_SOCKET, SO_ERROR, &err, &optlen);
 153                 if (res)
 154                         return errno;
 155                 if (err)
 156                         return err;
 157         }
 158
 159         return 0;
 160 }