
KRB5_KRBHST_INIT(3)      BSD Library Functions Manual      KRB5_KRBHST_INIT(3)

NAME
     krb5_krbhst_init, krb5_krbhst_init_flags, krb5_krbhst_next,
     krb5_krbhst_next_as_string, krb5_krbhst_reset, krb5_krbhst_free,
     krb5_krbhst_format_string, krb5_krbhst_get_addrinfo -- lookup Kerberos
     KDC hosts

LIBRARY
     Kerberos 5 Library (libkrb5, -lkrb5)

SYNOPSIS
     #include <krb5.h>

     krb5_error_code
     krb5_krbhst_init(krb5_context context, const char *realm,
         unsigned int type, krb5_krbhst_handle *handle);

     krb5_error_code
     krb5_krbhst_init_flags(krb5_context context, const char *realm,
         unsigned int type, int flags, krb5_krbhst_handle *handle);

     krb5_error_code
     krb5_krbhst_next(krb5_context context, krb5_krbhst_handle handle,
         krb5_krbhst_info **host);

     krb5_error_code
     krb5_krbhst_next_as_string(krb5_context context,
         krb5_krbhst_handle handle, char *hostname, size_t hostlen);

     void
     krb5_krbhst_reset(krb5_context context, krb5_krbhst_handle handle);

     void
     krb5_krbhst_free(krb5_context context, krb5_krbhst_handle handle);

     krb5_error_code
     krb5_krbhst_format_string(krb5_context context,
         const krb5_krbhst_info *host, char *hostname, size_t hostlen);

     krb5_error_code
     krb5_krbhst_get_addrinfo(krb5_context context, krb5_krbhst_info *host,
         struct addrinfo **ai);

DESCRIPTION
     These functions are used to sequence through all Kerberos hosts of a par-
     ticular realm and service. The service type can be the KDCs, the adminis-
     trative servers, the password changing servers, or the servers for Ker-
     beros 4 ticket conversion.

     First a handle to a particular service is obtained by calling
     krb5_krbhst_init() (or krb5_krbhst_init_flags()) with the realm of inter-
     est and the type of service to lookup. The type can be one of:

           KRB5_KRBHST_KDC
           KRB5_KRBHST_ADMIN
           KRB5_KRBHST_CHANGEPW
           KRB5_KRBHST_KRB524

     The handle is returned to the caller, and should be passed to the other
     functions.

     The flag argument to krb5_krbhst_init_flags is the same flags as
     krb5_send_to_kdc_flags() uses.  Possible values are:

           KRB5_KRBHST_FLAGS_MASTER     only talk to master (readwrite) KDC
           KRB5_KRBHST_FLAGS_LARGE_MSG  this is a large message, so use trans-
                                        port that can handle that.

     For each call to krb5_krbhst_next() information on a new host is
     returned. The former function returns in host a pointer to a structure
     containing information about the host, such as protocol, hostname, and
     port:

           typedef struct krb5_krbhst_info {
               enum { KRB5_KRBHST_UDP,
                      KRB5_KRBHST_TCP,
                      KRB5_KRBHST_HTTP } proto;
               unsigned short port;
               struct addrinfo *ai;
               struct krb5_krbhst_info *next;
               char hostname[1];
           } krb5_krbhst_info;

     The related function, krb5_krbhst_next_as_string(), return the same
     information as a URL-like string.

     When there are no more hosts, these functions return KRB5_KDC_UNREACH.

     To re-iterate over all hosts, call krb5_krbhst_reset() and the next call
     to krb5_krbhst_next() will return the first host.

     When done with the handle, krb5_krbhst_free() should be called.

     To use a krb5_krbhst_info, there are two functions:
     krb5_krbhst_format_string() that will return a printable representation
     of that struct and krb5_krbhst_get_addrinfo() that will return a struct
     addrinfo that can then be used for communicating with the server men-
     tioned.

EXAMPLES
     The following code will print the KDCs of the realm ``MY.REALM'':

           krb5_krbhst_handle handle;
           char host[MAXHOSTNAMELEN];
           krb5_krbhst_init(context, "MY.REALM", KRB5_KRBHST_KDC, &handle);
           while(krb5_krbhst_next_as_string(context, handle,
                                            host, sizeof(host)) == 0)
               printf("%s\n", host);
           krb5_krbhst_free(context, handle);

SEE ALSO
     getaddrinfo(3), krb5_get_krbhst(3), krb5_send_to_kdc_flags(3)

HISTORY
     These functions first appeared in Heimdal 0.3g.

HEIMDAL                          May 10, 2005                          HEIMDAL
