/*
* rfc931() speaks a common subset of the RFC 931, AUTH, TAP, IDENT and RFC
* 1413 protocols. It queries an RFC 931 etc. compatible daemon on a remote
* host to look up the owner of a connection. The information should not be
* used for authentication purposes. This routine intercepts alarm signals.
*
* Diagnostics are reported through syslog(3).
*
* Author: Wietse Venema, Eindhoven University of Technology, The Netherlands.
*/
/* address family must be the same */
if (rmt_sin->sa_family != our_sin->sa_family) {
strlcpy(dest, unknown, STRING_LENGTH);
return;
}
switch (rmt_sin->sa_family) {
case AF_INET:
salen = sizeof(struct sockaddr_in);
rmt_portp = &(((struct sockaddr_in *)rmt_sin)->sin_port);
break;
#ifdef INET6
case AF_INET6:
salen = sizeof(struct sockaddr_in6);
rmt_portp = &(((struct sockaddr_in6 *)rmt_sin)->sin6_port);
break;
#endif
default:
strlcpy(dest, unknown, STRING_LENGTH);
return;
}
switch (our_sin->sa_family) {
case AF_INET:
our_portp = &(((struct sockaddr_in *)our_sin)->sin_port);
break;
#ifdef INET6
case AF_INET6:
our_portp = &(((struct sockaddr_in6 *)our_sin)->sin6_port);
break;
#endif
default:
strlcpy(dest, unknown, STRING_LENGTH);
return;
}
/*
* Use one unbuffered stdio stream for writing to and for reading from
* the RFC931 etc. server. This is done because of a bug in the SunOS
* 4.1.x stdio library. The bug may live in other stdio implementations,
* too. When we use a single, buffered, bidirectional stdio stream ("r+"
* or "w+" mode) we read our own output. Such behaviour would make sense
* with resources that support random-access operations, but not with
* sockets.
*/
/*
* Set up a timer so we won't get stuck while waiting for the server.
*/
if (setjmp(timebuf) == 0) {
signal(SIGALRM, timeout);
alarm(rfc931_timeout);
/*
* Bind the local and remote ends of the query socket to the same
* IP addresses as the connection under investigation. We go
* through all this trouble because the local or remote system
* might have more than one network address. The RFC931 etc.
* client sends only port numbers; the server takes the IP
* addresses from the query socket.
*/
/*
* Send query to server. Neglect the risk that a 13-byte
* write would have to be fragmented by the local system and
* cause trouble with buggy System V stdio libraries.
*/
/*
* Read response from server. Use fgets()/sscanf() so we can
* work around System V stdio libraries that incorrectly
* assume EOF when a read from a socket returns less than
* requested.
*/
