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.\" Authors: Doug Rabson <dfr@rabson.org>
.\" Developed with Red Inc: Alfred Perlstein <alfred@FreeBSD.org>
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.Dd January 26, 2010
.Dt RPC_GSS_SET_CALLBACK 3
.Os
.Sh NAME
.Nm rpc_gss_set_callback
.Nd "Register a security context creation callback"
.Sh SYNOPSIS
.In rpc/rpcsec_gss.h
.Ft bool_t
.Fo (*callback)
.Fa "struct svc_req *req"
.Fa "gss_cred_id_t deleg"
.Fa "gss_ctx_id_t gss_context"
.Fa "rpc_gss_lock_t *lock"
.Fa "void **cookie"
.Fc
.Ft bool_t
.Fn rpc_gss_set_callback "rpc_gss_callback_t *cb"
.Sh DESCRIPTION
Register a function which will be called when new security contexts
are created on a server.
This function will be called on the first RPC request which uses that
context and has the opportunity of rejecting the request (for instance
after matching the request credentials to an access control list).
To accept the new security context, the callback should return
.Dv TRUE ,
otherwise
.Dv FALSE .
If the callback accepts a context, it becomes responsible for the
lifetime of the delegated client credentials (if any).
.Pp
It is also possible to 'lock' the values of service and quality of
protection used by the context.
If a context is locked, any subsequent requests which use different
values for service and quality of protection will be rejected.
.Sh PARAMETERS
.Bl -tag -width ".It gss_context"
.It cb
A structure containing the RPC program and version for this callback
and a function which will be called when new contexts are created for
the given RPC program and version
.It req
The RPC request using the new context
.It deleg
GSS-API delegated credentials (if any)
.It gss_context
The GSS-API context
.It lock
A structure used to enforce a particular QOP and service. Set
.Fa lock->locked
to
.Dv TRUE
to lock the service and QOP values
.It cookie
The callback function may set
.Fa *cookie
to any pointer sized value.
This value can be accessed during the lifetime of the context via
.Fn rpc_gss_getcred .
.El
.Sh RETURN VALUES
Returns
.Dv TRUE
if the callback was registered successfully or
.Dv FALSE
otherwise
.Sh AVAILABILITY
The
.Fn rpc_gss_set_callback
function is part of libtirpc.
.Sh SEE ALSO
.Xr rpc 3 ,
.Xr gssapi 3 ,
.Xr rpc_gss_getcred 3
.Xr rpcsec_gss 3
.Sh AUTHORS
This
manual page was written by
.An Doug Rabson Aq dfr@FreeBSD.org .
.Sh BUGS
There is no mechanism for informing a server when a security context
has been deleted.
This makes it difficult to allocate resources (e.g. to return via the
callback's
.Fa cookie
argument).