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         }
  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       r = setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &flags, sizeof flags);
  77       if (r == -1) {
  78         twarn("setting SO_REUSEADDR on fd %d", fd);
  79         close(fd);
  80         continue;
  81       }
  82       r = setsockopt(fd, SOL_SOCKET, SO_KEEPALIVE, &flags, sizeof flags);
  83       if (r == -1) {
  84         twarn("setting SO_KEEPALIVE on fd %d", fd);
  85         close(fd);
  86         continue;
  87       }
  88       r = setsockopt(fd, SOL_SOCKET, SO_LINGER, &linger, sizeof linger);
  89       if (r == -1) {
  90         twarn("setting SO_LINGER on fd %d", fd);
  91         close(fd);
  92         continue;
  93       }
  94       r = setsockopt(fd, IPPROTO_TCP, TCP_NODELAY, &flags, sizeof flags);
  95       if (r == -1) {
  96         twarn("setting TCP_NODELAY on fd %d", fd);
  97         close(fd);
  98         continue;
  99       }
 100
 101       if (verbose) {
 102           char hbuf[NI_MAXHOST], pbuf[NI_MAXSERV], *h = host, *p = port;
 103           r = getnameinfo(ai->ai_addr, ai->ai_addrlen,
 104                   hbuf, sizeof hbuf,
 105                   pbuf, sizeof pbuf,
 106                   NI_NUMERICHOST|NI_NUMERICSERV);
 107           if (!r) {
 108               h = hbuf;
 109               p = pbuf;
 110           }
 111           if (ai->ai_family == AF_INET6) {
 112               printf("bind %d [%s]:%s\n", fd, h, p);
 113           } else {
 114               printf("bind %d %s:%s\n", fd, h, p);
 115           }
 116       }
 117       r = bind(fd, ai->ai_addr, ai->ai_addrlen);
 118       if (r == -1) {
 119         twarn("bind()");
 120         close(fd);
 121         continue;
 122       }
 123
 124       r = listen(fd, 1024);
 125       if (r == -1) {
 126         twarn("listen()");
 127         close(fd);
 128         continue;
 129       }
 130
 131       break;
 132     }
 133
 134     freeaddrinfo(airoot);
 135
 136     if(ai == NULL)
 137       fd = -1;
 138
 139     return fd;
 140 }