KRB5_KRBHST_INIT(3) | 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/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.

May 10, 2005 | NetBSD 9.0