int raise(int sig)
{
int rc;
if ( os_signal( sig, &rc ) == NOTIMPLEMENTED )
os_freakout();
return rc;
}
int
main(int argc, char *argv[])
{
int listenfd;
int connfd;
int on = 1;
struct sockaddr_in serv_addr, cli_addr;
socklen_t cli_len;
pid_t childpid;
if ((listenfd = socket(AF_INET, SOCK_STREAM, 0)) < 0) {
fprintf(stderr, "socket error: %s\n", strerror(errno));
exit(1);
}
os_setsockopt(listenfd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on));
bzero(&serv_addr, sizeof(serv_addr));
serv_addr.sin_family = AF_INET;
serv_addr.sin_addr.s_addr = htonl(INADDR_ANY);
serv_addr.sin_port = htons(SERV_PORT);
if (bind(listenfd, (struct sockaddr *)&serv_addr, sizeof(serv_addr)) < 0) {
fprintf(stderr, "bind error: %s\n", strerror(errno));
exit(1);
}
if (listen(listenfd, LISTEN_QUEUE) < 0) {
fprintf(stderr, "listern error: %s\n", strerror(errno));
exit(1);
}
os_signal(SIGCHLD, sig_chld);
for (; ;) {
cli_len = sizeof(cli_addr);
if ((connfd = accept(listenfd, (struct sockaddr *)&cli_addr, &cli_len)) < 0) {
if (errno == EINTR)
continue;
else
os_err_sys("accept error");
}
if ((childpid = fork()) == 0) {
close(listenfd);
echo_string(connfd);
exit(1);
}
close(connfd);
}
return 0;
}
// ------------------------------------------------
// Function: icmp_parse()
// ------------------------------------------------
// Input: Message buffer
// Output: -
// ------------------------------------------------
// Description: Parse a ICMP message
// ------------------------------------------------
void icmp_parse(PPBUF pbuf)
{
// ---------------------
// checksum verification
// ---------------------
icmp_checksum(pbuf->data, pbuf->size);
if(chk_H != 0xff) return;
if(chk_L != 0xff) return;
// -------------------------------
// checks recognized message types
// -------------------------------
switch(ICMP(pbuf->data)->type) {
case PING_REQUEST:
// ---------
// answer it
// ---------
retain_buffer(pbuf);
ip_answer(pbuf);
ICMP(pbuf->data)->type = PING_REPLY;
// ---------------
// update checksum
// ---------------
ICMP(pbuf->data)->checksum = 0;
icmp_checksum(pbuf->data, pbuf->size);
ICMP(pbuf->data)->checksum = HTONS(~WORDOF(chk_H, chk_L));
// ----------------------------
// sends answer to IP interface
// ----------------------------
ip_send(pbuf);
release_buffer(pbuf);
break;
case PING_REPLY:
// --------------------------------------
// answer received, signal waiting thread
// --------------------------------------
os_signal(SIG_ICMP);
break;
}
}
