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