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)
  70 {
  71         struct sockaddr_un sun = {.sun_family = AF_UNIX};
  72         bool server = !!(type & USOCK_SERVER);
  73         int socktype = ((type & 0xff) == USOCK_TCP) ? SOCK_STREAM : SOCK_DGRAM;
  74
  75         if (strlen(host) >= sizeof(sun.sun_path)) {
  76                 errno = EINVAL;
  77                 return -1;
  78         }
  79         strcpy(sun.sun_path, host);
  80
  81         return usock_connect(type, (struct sockaddr*)&sun, sizeof(sun), AF_UNIX, socktype, server);
  82 }
  83
  84 int usock_inet(int type, const char *host, const char *service, void *addr)
  85 {
  86         int socktype = ((type & 0xff) == USOCK_TCP) ? SOCK_STREAM : SOCK_DGRAM;
  87         bool server = !!(type & USOCK_SERVER);
  88         struct addrinfo *result, *rp;
  89         struct addrinfo hints = {
  90                 .ai_family = (type & USOCK_IPV6ONLY) ? AF_INET6 :
  91                         (type & USOCK_IPV4ONLY) ? AF_INET : AF_UNSPEC,
  92                 .ai_socktype = socktype,
  93                 .ai_flags = AI_ADDRCONFIG
  94                         | ((type & USOCK_SERVER) ? AI_PASSIVE : 0)
  95                         | ((type & USOCK_NUMERIC) ? AI_NUMERICHOST : 0),
  96         };
  97         int sock = -1;
  98
  99         if (getaddrinfo(host, service, &hints, &result))
 100                 return -1;
 101
 102         for (rp = result; rp != NULL; rp = rp->ai_next) {
 103                 sock = usock_connect(type, rp->ai_addr, rp->ai_addrlen, rp->ai_family, socktype, server);
 104                 if (sock >= 0) {
 105                         if (addr)
 106                                 memcpy(addr, rp->ai_addr, rp->ai_addrlen);
 107                         break;
 108                 }
 109         }
 110
 111         freeaddrinfo(result);
 112         return sock;
 113 }
 114
 115 const char *usock_port(int port)
 116 {
 117         static char buffer[sizeof("65535\0")];
 118
 119         if (port < 0 || port > 65535)
 120                 return NULL;
 121
 122         snprintf(buffer, sizeof(buffer), "%u", port);
 123
 124         return buffer;
 125 }
 126
 127 int usock(int type, const char *host, const char *service) {
 128         int sock;
 129
 130         if (type & USOCK_UNIX)
 131                 sock = usock_unix(type, host);
 132         else
 133                 sock = usock_inet(type, host, service, NULL);
 134
 135         if (sock < 0)
 136                 return -1;
 137
 138         return sock;
 139 }
 140
 141 int usock_wait_ready(int fd, int msecs) {
 142         struct pollfd fds[1];
 143         int res;
 144
 145         fds[0].fd = fd;
 146         fds[0].events = POLLOUT;
 147
 148         res = poll(fds, 1, msecs);
 149         if (res < 0) {
 150                 return errno;
 151         } else if (res == 0) {
 152                 return -ETIMEDOUT;
 153         } else {
 154                 int err = 0;
 155                 socklen_t optlen = sizeof(err);
 156
 157                 res = getsockopt(fd, SOL_SOCKET, SO_ERROR, &err, &optlen);
 158                 if (res)
 159                         return errno;
 160                 if (err)
 161                         return err;
 162         }
 163
 164         return 0;
 165 }