4.3.1 Identification (Ident) coserver

The Identification protocol is briefly documented in RFC1413. It provides a means to determine the identity of a user of a particular TCP connection. Given a TCP port number pair, it returns a character string which identifies the owner of that connection on the server’s (that is the client’s) system.

This is a connection based application on TCP. A server listens for TCP connections on TCP port 113 (decimal). Once a connection is established, the server reads a line of data which specifies the connection of interest. If it exists, the system dependent user identifier of the connection of interest is sent as the reply. The server may then either shut down the connection or it may continue to read/respond to more queries.

The Ident coserver is a client to this kind of service. For every established network connection you can use this service by calling the appropriate macro from coserver.h. But you could also use the Ident coserver as is without this macro. The messages from Serveez to this coserver are formatted this way:

Format:
RemoteAddressInDottedDecimals ":" RemotePort ":" LocalPort

Macro:
svz_coserver_ident (sock, MyIdentCallback, sock->id, sock->version);

In this context sock is of type svz_socket_t and MyIdentCallback is something like the following example. Both of the last two (optional) arguments identify a valid socket structure and user can be NULL if there is no ident daemon running on the foreign machine. The last two argument within the above macro will be the last two arguments in the callback below. Thus you will know what kind of data the invocation of the callback is related to.

Callback:
int
MyIdentCallback (char *user, int id, int version)
{
  printf ("Identified user: %s\n", user);
  return 0;
}

4.3.2 Domain Name Server (DNS) coserver

The DNS coserver is using gethostbyname to translate a given hostname to the associated IP address. The format of the coserver input line and the macro from coserver.h is shown below. The IRC server is currently using this coserver for resolving its ‘?-Lines’. See Existing servers, for more information. In the example below realhost is something like ‘www.lkcc.org’.

Format:
RemoteHostname

Macro:
svz_coserver_dns (realhost, irc_connect_server, ircserver, NULL);

Callback:
int
irc_connect_server (char *ip, irc_server_t *server)
{
  printf ("The ip address is: %s\n", ip);
  return 0;
}

4.3.3 Reverse Domain Name Server (reverse DNS) coserver

As easily guessed from the name this coserver is just doing the reverse as the DNS coserver. It translates a given IP address into a hostname using gethostbyaddr. In the macro the ip address is given as an unsigned long in host byte order. The Reverse DNS coserver itself takes something like ‘192.168.2.1’.

Format:
RemoteAddressInDottedDecimals

Macro:
svz_coserver_reverse (addr, MyReverseCallback, sock->id, sock->version);

Callback:
int
MyReverseCallback (char *host, int id, int version)
{
  printf ("Hostname is: %s\n", host);
  return 0;
}