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 != 0) {
  52       twarnx("getaddrinfo(): %s", gai_strerror(r));
  53       return -1;
  54     }
  55
  56     for(ai = airoot; ai; ai = ai->ai_next) {
  57       fd = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
  58       if (fd == -1) {
  59         twarn("socket()");
  60         continue;
  61       }
  62
  63       flags = fcntl(fd, F_GETFL, 0);
  64       if (flags < 0) {
  65         twarn("getting flags");
  66         close(fd);
  67         continue;
  68       }
  69
  70       r = fcntl(fd, F_SETFL, flags | O_NONBLOCK);
  71       if (r == -1) {
  72         twarn("setting O_NONBLOCK");
  73         close(fd);
  74         continue;
  75       }
  76
  77       flags = 1;
  78       r = setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &flags, sizeof flags);
  79       if (r == -1) {
  80         twarn("setting SO_REUSEADDR on fd %d", fd);
  81         close(fd);
  82         continue;
  83       }
  84       r = setsockopt(fd, SOL_SOCKET, SO_KEEPALIVE, &flags, sizeof flags);
  85       if (r == -1) {
  86         twarn("setting SO_KEEPALIVE on fd %d", fd);
  87         close(fd);
  88         continue;
  89       }
  90       r = setsockopt(fd, SOL_SOCKET, SO_LINGER, &linger, sizeof linger);
  91       if (r == -1) {
  92         twarn("setting SO_LINGER on fd %d", fd);
  93         close(fd);
  94         continue;
  95       }
  96       r = setsockopt(fd, IPPROTO_TCP, TCP_NODELAY, &flags, sizeof flags);
  97       if (r == -1) {
  98         twarn("setting TCP_NODELAY on fd %d", fd);
  99         close(fd);
 100         continue;
 101       }
 102
 103       r = bind(fd, ai->ai_addr, ai->ai_addrlen);
 104       if (r == -1) {
 105         twarn("bind()");
 106         close(fd);
 107         continue;
 108       }
 109       if (verbose) {
 110           char hbuf[NI_MAXHOST], pbuf[NI_MAXSERV], *h = host, *p = port;
 111          struct sockaddr_in addr;
 112          socklen_t addrlen;
 113
 114          addrlen = sizeof(addr);
 115          r = getsockname(fd, (struct sockaddr *) &addr, &addrlen);
 116          if (!r) {
 117              r = getnameinfo((struct sockaddr *) &addr, addrlen,
 118                              hbuf, sizeof(hbuf),
 119                              pbuf, sizeof(pbuf),
 120                              NI_NUMERICHOST|NI_NUMERICSERV);
 121              if (!r) {
 122                  h = hbuf;
 123                  p = pbuf;
 124              }
 125          }
 126           if (ai->ai_family == AF_INET6) {
 127               printf("bind %d [%s]:%s\n", fd, h, p);
 128           } else {
 129               printf("bind %d %s:%s\n", fd, h, p);
 130           }
 131       }
 132
 133       r = listen(fd, 1024);
 134       if (r == -1) {
 135         twarn("listen()");
 136         close(fd);
 137         continue;
 138       }
 139
 140       break;
 141     }
 142
 143     freeaddrinfo(airoot);
 144
 145     if(ai == NULL)
 146       fd = -1;
 147
 148     return fd;
 149 }