s4-rpc_server: Add comments explaining the control flow around dcesrv_bind()

Signed-off-by: Andrew Bartlett <abartlet@samba.org>
Reviewed-by: Stefan Metzmacher <metze@samba.org>

diff --git a/source4/rpc_server/dcerpc_server.c b/source4/rpc_server/dcerpc_server.c
index 072e35249c0b065cc321d7dbf05949eaeba8f5ee..0d39744172e8702f68f2eabfef09f37c3dd2a164 100644 (file)
--- a/source4/rpc_server/dcerpc_server.c
+++ b/source4/rpc_server/dcerpc_server.c
@@ -792,6 +792,14 @@ static NTSTATUS dcesrv_bind(struct dcesrv_call_state *call)
 
        /*
         * Try to negotiate one new presentation context.
+        *
+        * Deep in here we locate the iface (by uuid) that the client
+        * requested, from the list of interfaces on the
+        * call->conn->endpoint, and call iface->bind() on that iface.
+        *
+        * call->conn was set up at the accept() of the socket, and
+        * call->conn->endpoint has a list of interfaces restricted to
+        * this port or pipe.
         */
        status = dcesrv_negotiate_contexts(call, &call->pkt.u.bind, ack_ctx_list);
        if (NT_STATUS_EQUAL(status, NT_STATUS_RPC_PROTOCOL_ERROR)) {
@@ -801,6 +809,12 @@ static NTSTATUS dcesrv_bind(struct dcesrv_call_state *call)
                return status;
        }
 
+       /*
+        * At this point we know which interface (eg netlogon, lsa,
+        * drsuapi) the caller requested.  This is available on
+        * call->conntext->iface.
+        */
+
        if ((call->pkt.pfc_flags & DCERPC_PFC_FLAG_CONC_MPX) &&
            (call->state_flags & DCESRV_CALL_STATE_FLAG_MULTIPLEXED)) {
                call->conn->state_flags |= DCESRV_CALL_STATE_FLAG_MULTIPLEXED;
@@ -811,7 +825,11 @@ static NTSTATUS dcesrv_bind(struct dcesrv_call_state *call)
                call->conn->state_flags |= DCESRV_CALL_STATE_FLAG_PROCESS_PENDING_CALL;
        }
 
-       /* handle any authentication that is being requested */
+       /*
+        * After finding the interface and setting up the NDR
+        * transport negotiation etc, handle any authentication that
+        * is being requested.
+        */
        if (!dcesrv_auth_bind(call)) {
                struct dcesrv_auth *auth = &call->conn->auth_state;
 
@@ -2246,6 +2264,13 @@ static void dcesrv_sock_accept(struct stream_connection *srv_conn)
                }
        }
 
+       /*
+        * This fills in dcesrv_conn->endpoint with the endpoint
+        * associated with the socket.  From this point on we know
+        * which (group of) services we are handling, but not the
+        * specific interface.
+        */
+
        status = dcesrv_endpoint_connect(dcesrv_sock->dcesrv_ctx,
                                         srv_conn,
                                         dcesrv_sock->endpoint,