KRB5\_KRBHST\_INIT(3) Library Functions Manual KRB5\_KRBHST\_INIT(3)

# [NAME](#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](#LIBRARY)

Kerberos 5 Library (libkrb5, -lkrb5)

# [SYNOPSIS](#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](#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`](#krb5_krbhst_init)() (or [`krb5_krbhst_init_flags`](#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`](#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`](#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`](#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`](#krb5_krbhst_reset)() and the next call to `krb5_krbhst_next`() will return the first host.

When done with the handle, [`krb5_krbhst_free`](#krb5_krbhst_free)() should be called.

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

# [EXAMPLES](#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](#SEE_ALSO)

[getaddrinfo(3)](/man/os/heimdal/getaddrinfo.3), [krb5\_get\_krbhst(3)](/man/os/heimdal/krb5_get_krbhst.3), [krb5\_send\_to\_kdc\_flags(3)](/man/os/heimdal/krb5_send_to_kdc_flags.3)

# [HISTORY](#HISTORY)

These functions first appeared in Heimdal 0.3g.

May 10, 2005 HEIMDAL

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Document: krb5_krbhst_next(3) from heimdal 7.8.0-r52 (Chainguard OS)
Source: https://github.com/heimdal/heimdal