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 <stdlib.h>
  24 #include <unistd.h>
  25 #include <fcntl.h>
  26 #include <errno.h>
  27 #include <string.h>
  28 #include <stdbool.h>
  29
  30 #include "usock.h"
  31
  32 static void usock_set_flags(int sock, unsigned int type)
  33 {
  34         if (!(type & USOCK_NOCLOEXEC))
  35                 fcntl(sock, F_SETFD, fcntl(sock, F_GETFD) | FD_CLOEXEC);
  36
  37         if (type & USOCK_NONBLOCK)
  38                 fcntl(sock, F_SETFL, fcntl(sock, F_GETFL) | O_NONBLOCK);
  39 }
  40
  41 static int usock_connect(struct sockaddr *sa, int sa_len, int family, int socktype, bool server)
  42 {
  43         int sock;
  44
  45         sock = socket(family, socktype, 0);
  46         if (sock < 0)
  47                 return -1;
  48
  49         if (server) {
  50                 const int one = 1;
  51                 setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one));
  52
  53                 if (!bind(sock, sa, sa_len) &&
  54                     (socktype != SOCK_STREAM || !listen(sock, SOMAXCONN)))
  55                         return sock;
  56         } else {
  57                 if (!connect(sock, sa, sa_len) || errno == EINPROGRESS)
  58                         return sock;
  59         }
  60
  61         close(sock);
  62         return -1;
  63 }
  64
  65 static int usock_unix(const char *host, int socktype, bool server)
  66 {
  67         struct sockaddr_un sun = {.sun_family = AF_UNIX};
  68
  69         if (strlen(host) >= sizeof(sun.sun_path)) {
  70                 errno = EINVAL;
  71                 return -1;
  72         }
  73         strcpy(sun.sun_path, host);
  74
  75         return usock_connect((struct sockaddr*)&sun, sizeof(sun), AF_UNIX, socktype, server);
  76 }
  77
  78 static int usock_inet(int type, const char *host, const char *service, int socktype, bool server)
  79 {
  80         struct addrinfo *result, *rp;
  81         struct addrinfo hints = {
  82                 .ai_family = (type & USOCK_IPV6ONLY) ? AF_INET6 :
  83                         (type & USOCK_IPV4ONLY) ? AF_INET : AF_UNSPEC,
  84                 .ai_socktype = socktype,
  85                 .ai_flags = AI_ADDRCONFIG
  86                         | ((type & USOCK_SERVER) ? AI_PASSIVE : 0)
  87                         | ((type & USOCK_NUMERIC) ? AI_NUMERICHOST : 0),
  88         };
  89         int sock = -1;
  90
  91         if (getaddrinfo(host, service, &hints, &result))
  92                 return -1;
  93
  94         for (rp = result; rp != NULL; rp = rp->ai_next) {
  95                 sock = usock_connect(rp->ai_addr, rp->ai_addrlen, rp->ai_family, socktype, server);
  96                 if (sock >= 0)
  97                         break;
  98         }
  99
 100         freeaddrinfo(result);
 101         return sock;
 102 }
 103
 104 int usock(int type, const char *host, const char *service) {
 105         int socktype = ((type & 0xff) == USOCK_TCP) ? SOCK_STREAM : SOCK_DGRAM;
 106         bool server = !!(type & USOCK_SERVER);
 107         int sock;
 108
 109         if (type & USOCK_UNIX)
 110                 sock = usock_unix(host, socktype, server);
 111         else
 112                 sock = usock_inet(type, host, service, socktype, server);
 113
 114         if (sock < 0)
 115                 return -1;
 116
 117         usock_set_flags(sock, type);
 118         return sock;
 119 }