Colin's git trees - cmccabe-bin/blob - show_default_sockopts.c

   1 #include <netinet/in.h>
   2 #include <netinet/tcp.h>
   3 #include <stdio.h>
   4 #include <stdlib.h>
   5 #include <sys/socket.h>
   6 #include <sys/types.h>
   7 #include <unistd.h>
   8
   9 /*
  10  * show_default_sockopts
  11  *
  12  * Show the default socket options
  13  *
  14  * Colin McCabe
  15  */
  16
  17 struct option_t {
  18         int opt;
  19         const char *descr;
  20 };
  21
  22 void option_query(int s, int type, struct option_t *p)
  23 {
  24         int value, vlen = 4;
  25
  26         for (; p->descr != NULL; ++p) {
  27                 if (getsockopt(s, type, p->opt, (void *)&value, &vlen) == -1) {
  28                         fprintf(stderr,"getsocketopts: could not test %s\n",
  29                                 p->descr);
  30                 }
  31                 else {
  32                         printf("Default %s = %d\n", p->descr, value);
  33                 }
  34         }
  35 }
  36
  37 struct option_t so_option[] = {
  38 #ifdef SO_ACCEPTCONN
  39         { SO_ACCEPTCONN, "SO_ACCEPTCON: accepting connections" },
  40 #endif
  41 #ifdef SO_BROADCAST
  42         { SO_BROADCAST, "SO_BROADCAST, broadcast allowed" },
  43 #endif
  44 #ifdef SO_REUSEADDR
  45         { SO_REUSEADDR, "SO_REUSEADDR, address recycling" },
  46 #endif
  47 #ifdef SO_KEEPALIVE
  48         { SO_KEEPALIVE, "SO_KEEPALIVE, send keepalive packets" },
  49 #endif
  50         /* { SO_LINGER, "SO_LINGER, lingers on close"}, */
  51 #ifdef SO_OOBINLINE
  52         { SO_OOBINLINE, "SO_OOBINLINE, oob data folded inline"},
  53 #endif
  54 #ifdef SO_SNDBUF
  55         { SO_SNDBUF, "SO_SNDBUF, send buffer size" },
  56 #endif
  57 #ifdef SO_RCVLOWAT
  58         { SO_RCVLOWAT, "SO_RCVLOWAT, receive low-water mark"},
  59 #endif
  60 #ifdef SO_SNDLOWAT
  61         { SO_SNDLOWAT, "SO_SNDLOWAT, send low-water mark"},
  62 #endif
  63 #ifdef SO_RCVTIMEO
  64         { SO_RCVTIMEO, "SO_RCVTIMEO, receive timeout"},
  65 #endif
  66 #ifdef SO_SNDTIMEO
  67         { SO_SNDTIMEO, "SO_SNDTIMEO, send timeout"},
  68 #endif
  69 #ifdef SO_RCVBUF
  70         { SO_RCVBUF, "SO_RCVBUF, receive buffer size"},
  71 #endif
  72 #ifdef SO_ERROR
  73         { SO_ERROR, "SO_ERROR, error status"},
  74 #endif
  75 #ifdef SO_TYPE
  76         { SO_TYPE, "SO_TYPE, socket type"},
  77 #endif
  78         { 0, NULL }
  79 };
  80
  81 struct option_t tcp_option[] = {
  82 #ifdef TCP_MAXSEG
  83           { TCP_MAXSEG, "TCP_MAXSEG, maximum segment size (mss)"},
  84 #endif
  85 #ifdef TCP_NODELAY
  86           { TCP_NODELAY, "TCP_NODELAY, send even tiny packets"},
  87 #endif
  88           { 0, NULL}
  89 };
  90
  91 int main(int argc, char **argv)
  92 {
  93         int s;
  94         if ((getuid()) != 0) {
  95                 fprintf(stderr,"%s: you must be root to run this program.\n", argv[0]);
  96                 return 1;
  97         }
  98
  99         if ((s = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP)) < 0) {
 100                 perror("failed to create a socket to test.");
 101                 return 1;
 102         }
 103         option_query(s, SOL_SOCKET, so_option);
 104         option_query(s, IPPROTO_TCP, tcp_option);
 105
 106         (void) close(s);
 107         return 0;
 108 }