Content-type: text/html Man page of dn_comp

dn_comp

Section: C Library Functions (3)
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NAME

dn_comp - Compresses a domain name  

LIBRARY

Standard C Library (libc.a)  

SYNOPSIS

#include <sys/types.h>

#include <netinet/in.h>

#include <arpa/nameser.h>

#include <resolv.h>

int dn_comp (
    u_char *expanded_name,
    u_char *compressed_name,
    int length,
    u_char **name_ptrs,
    u_char **end_ptr );  

PARAMETERS

Points to a domain name. Points to an array containing the compressed domain name. Specifies the size of the array pointed to by the compressed_name parameter. Specifies a list of pointers to previously compressed names in the current message. Points to the end of the array pointed to by the compressed_name parameter.  

DESCRIPTION

The dn_comp() (domain name compression) function compresses the domain name pointed to by the expanded_name parameter and stores it in the area pointed to by the compressed_name parameter.

The dn_comp() function inserts labels into the message as the name is compressed. The dn_comp() function also maintains a list of pointers to the message labels.

If the value of the name_ptrs parameter is null, the dn_comp() function does not compress any names, but instead translates a domain name from ASCII to internal format without removing suffixes (compressing). Otherwise, the name_ptrs parameter is the address of pointers to previously compressed suffixes.

If the end_ptr parameter is null, the dn_comp() function does not update the list of label pointers.

The dn_comp() function is one of a set of subroutines that form the resolver, a set of functions that resolves domain names. Global information that is used by the resolver functions is kept in the _res data structure. The /include/resolv.h file contains the _res data structure definition.  

RETURN VALUES

Upon successful completion, the dn_comp() function returns the size of the compressed domain name. Otherwise, a value of -1 is returned.  

FILES

Defines name server and domain name structures, constants, and values.  

RELATED INFORMATION

Functions: res_init(3), res_mkquery(3), res_send(3), dn_expand(3), dn_find(3), _getshort(3), _getlong(3), putshort(3), putlong(3), dn_skipname(3)

Commands: named(8) delim off


 

Index

NAME
LIBRARY
SYNOPSIS
PARAMETERS
DESCRIPTION
RETURN VALUES
FILES
RELATED INFORMATION

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Time: 02:42:08 GMT, October 02, 2010