net.c

   1 #include <netdb.h>
   2 #include <stdio.h>
   3 #include <unistd.h>
   4 #include <fcntl.h>
   5 #include <string.h>
   6 #include <errno.h>
   7 #include <sys/socket.h>
   8 #include <netinet/in.h>
   9 #include <netinet/tcp.h>
  10 #include "dat.h"
  11 #include "sd-daemon.h"
  12
  13 int
  14 make_server_socket(char *host, char *port)
  15 {
  16     int fd = -1, flags, r;
  17     struct linger linger = {0, 0};
  18     struct addrinfo *airoot, *ai, hints;
  19
  20     /* See if we got a listen fd from systemd. If so, all socket options etc
  21      * are already set, so we check that the fd is a TCP listen socket and
  22      * return. */
  23     r = sd_listen_fds(1);
  24     if (r < 0) {
  25         return twarn("sd_listen_fds"), -1;
  26     }
  27     if (r > 0) {
  28         if (r > 1) {
  29             twarnx("inherited more than one listen socket;"
  30                    " ignoring all but the first");
  31             r = 1;
  32         }
  33         fd = SD_LISTEN_FDS_START;
  34         r = sd_is_socket_inet(fd, 0, SOCK_STREAM, 1, 0);
  35         if (r < 0) {
  36             errno = -r;
  37             twarn("sd_is_socket_inet");
  38             return -1;
  39         }
  40         if (!r) {
  41             twarnx("inherited fd is not a TCP listen socket");
  42             return -1;
  43         }
  44         return fd;
  45     }
  46
  47     memset(&hints, 0, sizeof(hints));
  48     hints.ai_family = PF_UNSPEC;
  49     hints.ai_socktype = SOCK_STREAM;
  50     hints.ai_flags = AI_PASSIVE;
  51     r = getaddrinfo(host, port, &hints, &airoot);
  52     if (r == -1)
  53       return twarn("getaddrinfo()"), -1;
  54
  55     for(ai = airoot; ai; ai = ai->ai_next) {
  56       fd = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
  57       if (fd == -1) {
  58         twarn("socket()");
  59         continue;
  60       }
  61
  62       flags = fcntl(fd, F_GETFL, 0);
  63       if (flags < 0) {
  64         twarn("getting flags");
  65         close(fd);
  66         continue;
  67       }
  68
  69       r = fcntl(fd, F_SETFL, flags | O_NONBLOCK);
  70       if (r == -1) {
  71         twarn("setting O_NONBLOCK");
  72         close(fd);
  73         continue;
  74       }
  75
  76       flags = 1;
  77       r = setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &flags, sizeof flags);
  78       if (r == -1) {
  79         twarn("setting SO_REUSEADDR on fd %d", fd);
  80         close(fd);
  81         continue;
  82       }
  83       r = setsockopt(fd, SOL_SOCKET, SO_KEEPALIVE, &flags, sizeof flags);
  84       if (r == -1) {
  85         twarn("setting SO_KEEPALIVE on fd %d", fd);
  86         close(fd);
  87         continue;
  88       }
  89       r = setsockopt(fd, SOL_SOCKET, SO_LINGER, &linger, sizeof linger);
  90       if (r == -1) {
  91         twarn("setting SO_LINGER on fd %d", fd);
  92         close(fd);
  93         continue;
  94       }
  95       r = setsockopt(fd, IPPROTO_TCP, TCP_NODELAY, &flags, sizeof flags);
  96       if (r == -1) {
  97         twarn("setting TCP_NODELAY on fd %d", fd);
  98         close(fd);
  99         continue;
 100       }
 101
 102       if (verbose) {
 103           char hbuf[NI_MAXHOST], pbuf[NI_MAXSERV], *h = host, *p = port;
 104           r = getnameinfo(ai->ai_addr, ai->ai_addrlen,
 105                   hbuf, sizeof hbuf,
 106                   pbuf, sizeof pbuf,
 107                   NI_NUMERICHOST|NI_NUMERICSERV);
 108           if (!r) {
 109               h = hbuf;
 110               p = pbuf;
 111           }
 112           if (ai->ai_family == AF_INET6) {
 113               printf("bind %d [%s]:%s\n", fd, h, p);
 114           } else {
 115               printf("bind %d %s:%s\n", fd, h, p);
 116           }
 117       }
 118       r = bind(fd, ai->ai_addr, ai->ai_addrlen);
 119       if (r == -1) {
 120         twarn("bind()");
 121         close(fd);
 122         continue;
 123       }
 124
 125       r = listen(fd, 1024);
 126       if (r == -1) {
 127         twarn("listen()");
 128         close(fd);
 129         continue;
 130       }
 131
 132       break;
 133     }
 134
 135     freeaddrinfo(airoot);
 136
 137     if(ai == NULL)
 138       fd = -1;
 139
 140     return fd;
 141 }