dn_comp(3) [osf1 man page]
dn_comp(3) Library Functions Manual dn_comp(3) NAME
dn_comp - Compresses a domain name LIBRARY
Standard C Library (libc.a, libc.so) SYNOPSIS
#include <sys/types.h> #include <netinet/in.h> #include <arpa/nameser.h> #include <resolv.h> int dn_comp ( const 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 com- pressed_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. The list ends with NULL. 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 infor- mation 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 and the h_errno external variable is set with an error code, if any. Error code values and reasons are defined in <netdb.h>. FILES
Defines name server and domain name structures, constants, and values. RELATED INFORMATION
Functions: dn_expand(3), dn_find(3), dn_skipname(3), putshort(3), putlong(3), res_init(3), res_mkquery(3), res_query(3), res_search(3), res_send(3), _getshort(3), _getlong(3). Commands: named(8). delim off dn_comp(3)
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res_search(3) Library Functions Manual res_search(3) NAME
res_search, res_query - Queries domain server and checks response LIBRARY
Standard C Library (libc.a, libc.so) SYNOPSIS
#include <sys/types.h> #include <netinet/in.h> #include <arpa/nameser.h> #include <resolv.h> int res_search ( const char *domain_name, int class, int type, u_char *answer, int answer_len;) The res_query syntax is as follows: int res_query ( const char *domain_name, int class, int type, u_char *answer, int answer_len;) PARAMETERS
Points to the fully-qualified name of the domain. If the domain_name parameter points to a single label and the RES_DEFNAMES bit is set, as it is by default, the function appends domain_name to the current domain name. The current domain name is defined by the name server in use or in the /etc/resolv.conf file. Specifies one of the following parameters: Specifies the ARPA Internet. Specifies the Chaos network at MIT. Requires one of the following values: Host address Authoritative server Mail destination Mail forwarder Canonical name Start of authority zone Mailbox domain name Mail group member Mail rename name NULL resource record Well known service Domain name pointer Host information Mailbox information Mail routing information User (finger) information User ID Group ID Points to a location of the server's reply. Specifies the length of the answer pointed to by the answer parameter. DESCRIPTION
The res_search() and res_query() functions construct a query, send it to the local server, and await a response. In addition, res_search() implements the default and search rules specified by the RES_DEFNAMES and RES_DNSRCH resolver options. The function returns the first suc- cessful reply. The res_search() and res_query() functions part of a set of subroutines that form the resolver, a set of functions that resolve 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 res_search() function returns the size of the answer. If the answer is larger than the value of the answer_len parameter, the function fails and returns a value of -1. ERRORS
If an error occurs during a resolver operation, the h_errno external variable is set. Error code values and reasons are defined in <netdb.h>. FILES
Contains the name server and domain name. RELATED INFORMATION
Functions: dn_comp(3), dn_expand(3), dn_find(3), dn_skipname(3), _getlong(3), _getshort(3), putlong(3), putshort(3), res_init(3), res_mkquery(3), res_query(3), res_send(3). delim off res_search(3)