dn_expand()

Expand a compressed Internet domain name

Synopsis:

#include <sys/types.h>
#include <netinet/in.h>
#include <arpa/nameser.h>
#include <resolv.h>

int dn_expand( const u_char * msg, 
               const u_char * eomorig, 
               const u_char * comp_dn, 
               char * exp_dn, 
               int length );

Arguments:

msg: A pointer to the beginning of the message that contains the compressed name.
eomorig: A pointer to the first location after the message.
comp_dn: The compressed name that you want to expand.
exp_dn: A buffer where the function can store the expanded name.
length: The length of the array specified by exp_dn.

Library:

libsocket

Use the -l socket option to qcc to link against this library.

Description:

The dn_expand() function is a low-level routine used by res_query() to expand the compressed domain name, comp_dn, to a full domain name.

The compressed name is contained in a query or reply message.

Based on:

RFC 974, RFC 1032, RFC 1033, RFC 1034, RFC 1035

Returns:

The size of the compressed domain name (not the expanded name), in bytes, or -1 if an error occurs.

Classification:

Unix

Safety:
Cancellation point	No
Interrupt handler	No
Signal handler	Yes
Thread	Yes