The Linux Programming Interface

Sockets: Advanced Topics 1265

Listing 61-3: Using getsockname() and getpeername()

–––––––––––––––––––––––––––––––––––––––––––––––––––––– sockets/socknames.c
#include "inet_sockets.h" / Declares our socket functions /
#include "tlpi_hdr.h"

int
main(int argc, char argv[])
{
int listenFd, acceptFd, connFd;
socklen_t len; / Size of socket address buffer /
void addr; / Buffer for socket address /
char addrStr[IS_ADDR_STR_LEN];

if (argc != 2 || strcmp(argv[1], "--help") == 0)
usageErr("%s service\n", argv[0]);

listenFd = inetListen(argv[1], 5, &len);
if (listenFd == -1)
errExit("inetListen");

connFd = inetConnect(NULL, argv[1], SOCK_STREAM);
if (connFd == -1)
errExit("inetConnect");

acceptFd = accept(listenFd, NULL, NULL);
if (acceptFd == -1)
errExit("accept");

addr = malloc(len);
if (addr == NULL)
errExit("malloc");

if (getsockname(connFd, addr, &len) == -1)
errExit("getsockname");
printf("getsockname(connFd): %s\n",
inetAddressStr(addr, len, addrStr, IS_ADDR_STR_LEN));
if (getsockname(acceptFd, addr, &len) == -1)
errExit("getsockname");
printf("getsockname(acceptFd): %s\n",
inetAddressStr(addr, len, addrStr, IS_ADDR_STR_LEN));

if (getpeername(connFd, addr, &len) == -1)
errExit("getpeername");
printf("getpeername(connFd): %s\n",
inetAddressStr(addr, len, addrStr, IS_ADDR_STR_LEN));
if (getpeername(acceptFd, addr, &len) == -1)
errExit("getpeername");
printf("getpeername(acceptFd): %s\n",
inetAddressStr(addr, len, addrStr, IS_ADDR_STR_LEN));

sleep(30); / Give us time to run netstat(8) /
exit(EXIT_SUCCESS);
}
–––––––––––––––––––––––––––––––––––––––––––––––––––––– sockets/socknames.c