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 #include <stdio.h>
  30
  31 #include "usock.h"
  32
  33 static void usock_set_flags(int sock, unsigned int type)
  34 {
  35         if (!(type & USOCK_NOCLOEXEC))
  36                 fcntl(sock, F_SETFD, fcntl(sock, F_GETFD) | FD_CLOEXEC);
  37
  38         if (type & USOCK_NONBLOCK)
  39                 fcntl(sock, F_SETFL, fcntl(sock, F_GETFL) | O_NONBLOCK);
  40 }
  41
  42 static int usock_connect(struct sockaddr *sa, int sa_len, int family, int socktype, bool server)
  43 {
  44         int sock;
  45
  46         sock = socket(family, socktype, 0);
  47         if (sock < 0)
  48                 return -1;
  49
  50         if (server) {
  51                 const int one = 1;
  52                 setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one));
  53
  54                 if (!bind(sock, sa, sa_len) &&
  55                     (socktype != SOCK_STREAM || !listen(sock, SOMAXCONN)))
  56                         return sock;
  57         } else {
  58                 if (!connect(sock, sa, sa_len) || errno == EINPROGRESS)
  59                         return sock;
  60         }
  61
  62         close(sock);
  63         return -1;
  64 }
  65
  66 static int usock_unix(const char *host, int socktype, bool server)
  67 {
  68         struct sockaddr_un sun = {.sun_family = AF_UNIX};
  69
  70         if (strlen(host) >= sizeof(sun.sun_path)) {
  71                 errno = EINVAL;
  72                 return -1;
  73         }
  74         strcpy(sun.sun_path, host);
  75
  76         return usock_connect((struct sockaddr*)&sun, sizeof(sun), AF_UNIX, socktype, server);
  77 }
  78
  79 static int usock_inet(int type, const char *host, const char *service, int socktype, bool server)
  80 {
  81         struct addrinfo *result, *rp;
  82         struct addrinfo hints = {
  83                 .ai_family = (type & USOCK_IPV6ONLY) ? AF_INET6 :
  84                         (type & USOCK_IPV4ONLY) ? AF_INET : AF_UNSPEC,
  85                 .ai_socktype = socktype,
  86                 .ai_flags = AI_ADDRCONFIG
  87                         | ((type & USOCK_SERVER) ? AI_PASSIVE : 0)
  88                         | ((type & USOCK_NUMERIC) ? AI_NUMERICHOST : 0),
  89         };
  90         int sock = -1;
  91
  92         if (getaddrinfo(host, service, &hints, &result))
  93                 return -1;
  94
  95         for (rp = result; rp != NULL; rp = rp->ai_next) {
  96                 sock = usock_connect(rp->ai_addr, rp->ai_addrlen, rp->ai_family, socktype, server);
  97                 if (sock >= 0)
  98                         break;
  99         }
 100
 101         freeaddrinfo(result);
 102         return sock;
 103 }
 104
 105 const char *usock_port(int port)
 106 {
 107         static char buffer[sizeof("65535\0")];
 108
 109         if (port < 0 || port > 65535)
 110                 return NULL;
 111
 112         snprintf(buffer, sizeof(buffer), "%u", port);
 113
 114         return buffer;
 115 }
 116
 117 int usock(int type, const char *host, const char *service) {
 118         int socktype = ((type & 0xff) == USOCK_TCP) ? SOCK_STREAM : SOCK_DGRAM;
 119         bool server = !!(type & USOCK_SERVER);
 120         int sock;
 121
 122         if (type & USOCK_UNIX)
 123                 sock = usock_unix(host, socktype, server);
 124         else
 125                 sock = usock_inet(type, host, service, socktype, server);
 126
 127         if (sock < 0)
 128                 return -1;
 129
 130         usock_set_flags(sock, type);
 131         return sock;
 132 }