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 particular realm and
     service. The service type can be the KDCs, the administrative servers, the password changing
     servers, or the servers for Kerberos 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 interest 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 transport 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 mentioned.

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.