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;
  25         socklen_t vlen = 4;
  26
  27         for (; p->descr != NULL; ++p) {
  28                 if (getsockopt(s, type, p->opt, (void *)&value, &vlen) == -1) {
  29                         fprintf(stderr,"getsocketopts: could not test %s\n",
  30                                 p->descr);
  31                 }
  32                 else {
  33                         printf("Default %s = %d\n", p->descr, value);
  34                 }
  35         }
  36 }
  37
  38 struct option_t so_option[] = {
  39 #ifdef SO_ACCEPTCONN
  40         { SO_ACCEPTCONN, "SO_ACCEPTCON: accepting connections" },
  41 #endif
  42 #ifdef SO_BROADCAST
  43         { SO_BROADCAST, "SO_BROADCAST, broadcast allowed" },
  44 #endif
  45 #ifdef SO_REUSEADDR
  46         { SO_REUSEADDR, "SO_REUSEADDR, address recycling" },
  47 #endif
  48 #ifdef SO_KEEPALIVE
  49         { SO_KEEPALIVE, "SO_KEEPALIVE, send keepalive packets" },
  50 #endif
  51         /* { SO_LINGER, "SO_LINGER, lingers on close"}, */
  52 #ifdef SO_OOBINLINE
  53         { SO_OOBINLINE, "SO_OOBINLINE, oob data folded inline"},
  54 #endif
  55 #ifdef SO_SNDBUF
  56         { SO_SNDBUF, "SO_SNDBUF, send buffer size" },
  57 #endif
  58 #ifdef SO_RCVLOWAT
  59         { SO_RCVLOWAT, "SO_RCVLOWAT, receive low-water mark"},
  60 #endif
  61 #ifdef SO_SNDLOWAT
  62         { SO_SNDLOWAT, "SO_SNDLOWAT, send low-water mark"},
  63 #endif
  64 #ifdef SO_RCVTIMEO
  65         { SO_RCVTIMEO, "SO_RCVTIMEO, receive timeout"},
  66 #endif
  67 #ifdef SO_SNDTIMEO
  68         { SO_SNDTIMEO, "SO_SNDTIMEO, send timeout"},
  69 #endif
  70 #ifdef SO_RCVBUF
  71         { SO_RCVBUF, "SO_RCVBUF, receive buffer size"},
  72 #endif
  73 #ifdef SO_ERROR
  74         { SO_ERROR, "SO_ERROR, error status"},
  75 #endif
  76 #ifdef SO_TYPE
  77         { SO_TYPE, "SO_TYPE, socket type"},
  78 #endif
  79         { 0, NULL }
  80 };
  81
  82 struct option_t tcp_option[] = {
  83 #ifdef TCP_MAXSEG
  84           { TCP_MAXSEG, "TCP_MAXSEG, maximum segment size (mss)"},
  85 #endif
  86 #ifdef TCP_NODELAY
  87           { TCP_NODELAY, "TCP_NODELAY, send even tiny packets"},
  88 #endif
  89           { 0, NULL}
  90 };
  91
  92 int main(int argc, char **argv)
  93 {
  94         int s;
  95         if ((getuid()) != 0) {
  96                 fprintf(stderr,"%s: you must be root to run this program.\n", argv[0]);
  97                 return 1;
  98         }
  99
 100         if ((s = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP)) < 0) {
 101                 perror("failed to create a socket to test.");
 102                 return 1;
 103         }
 104         option_query(s, SOL_SOCKET, so_option);
 105         option_query(s, IPPROTO_TCP, tcp_option);
 106
 107         (void) close(s);
 108         return 0;
 109 }