net.c

   1 #include <netdb.h>
   2 #include <unistd.h>
   3 #include <fcntl.h>
   4 #include <string.h>
   5 #include <errno.h>
   6 #include <sys/socket.h>
   7 #include <netinet/in.h>
   8 #include <netinet/tcp.h>
   9 #include "dat.h"
  10 #include "sd-daemon.h"
  11
  12 int
  13 make_server_socket(char *host, char *port)
  14 {
  15     int fd = -1, flags, r;
  16     struct linger linger = {0, 0};
  17     struct addrinfo *airoot, *ai, hints;
  18
  19     /* See if we got a listen fd from systemd. If so, all socket options etc
  20      * are already set, so we check that the fd is a TCP listen socket and
  21      * return. */
  22     r = sd_listen_fds(1);
  23     if (r < 0) {
  24         return twarn("sd_listen_fds"), -1;
  25     }
  26     if (r > 0) {
  27         if (r > 1) {
  28             twarnx("inherited more than one listen socket;"
  29                    " ignoring all but the first");
  30             r = 1;
  31         }
  32         fd = SD_LISTEN_FDS_START;
  33         r = sd_is_socket_inet(fd, 0, SOCK_STREAM, 1, 0);
  34         if (r < 0) {
  35             errno = -r;
  36             twarn("sd_is_socket_inet");
  37             return -1;
  38         }
  39         if (!r) {
  40             twarnx("inherited fd is not a TCP listen socket");
  41             return -1;
  42         }
  43         return fd;
  44     }
  45
  46     memset(&hints, 0, sizeof(hints));
  47     hints.ai_family = PF_UNSPEC;
  48     hints.ai_socktype = SOCK_STREAM;
  49     hints.ai_flags = AI_PASSIVE;
  50     r = getaddrinfo(host, port, &hints, &airoot);
  51     if (r == -1)
  52       return twarn("getaddrinfo()"), -1;
  53
  54     for(ai = airoot; ai; ai = ai->ai_next) {
  55       fd = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
  56       if (fd == -1) {
  57         twarn("socket()");
  58         continue;
  59       }
  60
  61       flags = fcntl(fd, F_GETFL, 0);
  62       if (flags < 0) {
  63         twarn("getting flags");
  64         close(fd);
  65         continue;
  66       }
  67
  68       r = fcntl(fd, F_SETFL, flags | O_NONBLOCK);
  69       if (r == -1) {
  70         twarn("setting O_NONBLOCK");
  71         close(fd);
  72         continue;
  73       }
  74
  75       flags = 1;
  76       setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &flags, sizeof flags);
  77       setsockopt(fd, SOL_SOCKET, SO_KEEPALIVE, &flags, sizeof flags);
  78       setsockopt(fd, SOL_SOCKET, SO_LINGER,   &linger, sizeof linger);
  79       setsockopt(fd, IPPROTO_TCP, TCP_NODELAY, &flags, sizeof flags);
  80
  81       r = bind(fd, ai->ai_addr, ai->ai_addrlen);
  82       if (r == -1) {
  83         twarn("bind()");
  84         close(fd);
  85         continue;
  86       }
  87
  88       r = listen(fd, 1024);
  89       if (r == -1) {
  90         twarn("listen()");
  91         close(fd);
  92         continue;
  93       }
  94
  95       break;
  96     }
  97
  98     freeaddrinfo(airoot);
  99
 100     if(ai == NULL)
 101       fd = -1;
 102
 103     return fd;
 104 }