1/*
2 * ng_UI.c
3 */
4
5/*-
6 * Copyright (c) 1996-1999 Whistle Communications, Inc.
7 * All rights reserved.
8 *
9 * Subject to the following obligations and disclaimer of warranty, use and
10 * redistribution of this software, in source or object code forms, with or
11 * without modifications are expressly permitted by Whistle Communications;
12 * provided, however, that:
13 * 1. Any and all reproductions of the source or object code must include the
14 *    copyright notice above and the following disclaimer of warranties; and
15 * 2. No rights are granted, in any manner or form, to use Whistle
16 *    Communications, Inc. trademarks, including the mark "WHISTLE
17 *    COMMUNICATIONS" on advertising, endorsements, or otherwise except as
18 *    such appears in the above copyright notice or in the software.
19 *
20 * THIS SOFTWARE IS BEING PROVIDED BY WHISTLE COMMUNICATIONS "AS IS", AND
21 * TO THE MAXIMUM EXTENT PERMITTED BY LAW, WHISTLE COMMUNICATIONS MAKES NO
22 * REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED, REGARDING THIS SOFTWARE,
23 * INCLUDING WITHOUT LIMITATION, ANY AND ALL IMPLIED WARRANTIES OF
24 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT.
25 * WHISTLE COMMUNICATIONS DOES NOT WARRANT, GUARANTEE, OR MAKE ANY
26 * REPRESENTATIONS REGARDING THE USE OF, OR THE RESULTS OF THE USE OF THIS
27 * SOFTWARE IN TERMS OF ITS CORRECTNESS, ACCURACY, RELIABILITY OR OTHERWISE.
28 * IN NO EVENT SHALL WHISTLE COMMUNICATIONS BE LIABLE FOR ANY DAMAGES
29 * RESULTING FROM OR ARISING OUT OF ANY USE OF THIS SOFTWARE, INCLUDING
30 * WITHOUT LIMITATION, ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
31 * PUNITIVE, OR CONSEQUENTIAL DAMAGES, PROCUREMENT OF SUBSTITUTE GOODS OR
32 * SERVICES, LOSS OF USE, DATA OR PROFITS, HOWEVER CAUSED AND UNDER ANY
33 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
34 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
35 * THIS SOFTWARE, EVEN IF WHISTLE COMMUNICATIONS IS ADVISED OF THE POSSIBILITY
36 * OF SUCH DAMAGE.
37 *
38 * Author: Julian Elischer <julian@freebsd.org>
39 *
40 * $FreeBSD$
41 * $Whistle: ng_UI.c,v 1.14 1999/11/01 09:24:51 julian Exp $
42 */
43
44#include <sys/param.h>
45#include <sys/systm.h>
46#include <sys/errno.h>
47#include <sys/kernel.h>
48#include <sys/malloc.h>
49#include <sys/mbuf.h>
50#include <sys/errno.h>
51
52
53#include <netgraph/ng_message.h>
54#include <netgraph/netgraph.h>
55#include <netgraph/ng_UI.h>
56
57/*
58 * DEFINITIONS
59 */
60
61/* Everything, starting with sdlc on has defined UI as 0x03 */
62#define HDLC_UI	0x03
63
64/* Node private data */
65struct ng_UI_private {
66	hook_p  downlink;
67	hook_p  uplink;
68};
69typedef struct ng_UI_private *priv_p;
70
71/* Netgraph node methods */
72static ng_constructor_t	ng_UI_constructor;
73static ng_rcvmsg_t	ng_UI_rcvmsg;
74static ng_shutdown_t	ng_UI_shutdown;
75static ng_newhook_t	ng_UI_newhook;
76static ng_rcvdata_t	ng_UI_rcvdata;
77static ng_disconnect_t	ng_UI_disconnect;
78
79/* Node type descriptor */
80static struct ng_type typestruct = {
81	.version =	NG_ABI_VERSION,
82	.name =		NG_UI_NODE_TYPE,
83	.constructor =	ng_UI_constructor,
84	.rcvmsg =	ng_UI_rcvmsg,
85	.shutdown =	ng_UI_shutdown,
86	.newhook =	ng_UI_newhook,
87	.rcvdata =	ng_UI_rcvdata,
88	.disconnect =	ng_UI_disconnect,
89};
90NETGRAPH_INIT(UI, &typestruct);
91
92/************************************************************************
93			NETGRAPH NODE STUFF
94 ************************************************************************/
95
96/*
97 * Create a newborn node. We start with an implicit reference.
98 */
99
100static int
101ng_UI_constructor(node_p node)
102{
103	priv_p  priv;
104
105	/* Allocate private structure */
106	priv = malloc(sizeof(*priv), M_NETGRAPH, M_WAITOK | M_ZERO);
107	NG_NODE_SET_PRIVATE(node, priv);
108	return (0);
109}
110
111/*
112 * Give our ok for a hook to be added
113 */
114static int
115ng_UI_newhook(node_p node, hook_p hook, const char *name)
116{
117	const priv_p priv = NG_NODE_PRIVATE(node);
118
119	if (!strcmp(name, NG_UI_HOOK_DOWNSTREAM)) {
120		if (priv->downlink)
121			return (EISCONN);
122		priv->downlink = hook;
123	} else if (!strcmp(name, NG_UI_HOOK_UPSTREAM)) {
124		if (priv->uplink)
125			return (EISCONN);
126		priv->uplink = hook;
127	} else
128		return (EINVAL);
129	return (0);
130}
131
132/*
133 * Receive a control message
134 */
135static int
136ng_UI_rcvmsg(node_p node, item_p item, hook_p lasthook)
137{
138	int	error;
139	const priv_p priv = NG_NODE_PRIVATE(node);
140	struct ng_mesg *msg;
141
142	msg = NGI_MSG(item); /* only peeking */
143	if ((msg->header.typecookie == NGM_FLOW_COOKIE) && lasthook)  {
144		if (lasthook == priv->downlink) {
145			if (priv->uplink) {
146				NG_FWD_ITEM_HOOK(error, item, priv->uplink);
147				return (error);
148			}
149		} else {
150			if (priv->downlink) {
151				NG_FWD_ITEM_HOOK(error, item, priv->downlink);
152				return (error);
153			}
154		}
155	}
156
157	NG_FREE_ITEM(item);
158	return (EINVAL);
159}
160
161#define MAX_ENCAPS_HDR	1
162#define ERROUT(x)	do { error = (x); goto done; } while (0)
163
164/*
165 * Receive a data frame
166 */
167static int
168ng_UI_rcvdata(hook_p hook, item_p item)
169{
170	const node_p node = NG_HOOK_NODE(hook);
171	const priv_p priv = NG_NODE_PRIVATE(node);
172	struct mbuf *m;
173	int error = 0;
174
175	NGI_GET_M(item, m);
176	if (hook == priv->downlink) {
177		u_char *start, *ptr;
178
179		if (m->m_len < MAX_ENCAPS_HDR
180		    && !(m = m_pullup(m, MAX_ENCAPS_HDR)))
181			ERROUT(ENOBUFS);
182		ptr = start = mtod(m, u_char *);
183
184		/* Must be UI frame */
185		if (*ptr++ != HDLC_UI)
186			ERROUT(0);
187
188		m_adj(m, ptr - start);
189		NG_FWD_NEW_DATA(error, item, priv->uplink, m);	/* m -> NULL */
190	} else if (hook == priv->uplink) {
191		M_PREPEND(m, 1, M_NOWAIT);	/* Prepend IP NLPID */
192		if (!m)
193			ERROUT(ENOBUFS);
194		mtod(m, u_char *)[0] = HDLC_UI;
195		NG_FWD_NEW_DATA(error, item, priv->downlink, m);	/* m -> NULL */
196	} else
197		panic("%s", __func__);
198
199done:
200	NG_FREE_M(m);	/* does nothing if m == NULL */
201	if (item)
202		NG_FREE_ITEM(item);
203	return (error);
204}
205
206/*
207 * Shutdown node
208 */
209static int
210ng_UI_shutdown(node_p node)
211{
212	const priv_p priv = NG_NODE_PRIVATE(node);
213
214	/* Take down netgraph node */
215	free(priv, M_NETGRAPH);
216	NG_NODE_SET_PRIVATE(node, NULL);
217	NG_NODE_UNREF(node);
218	return (0);
219}
220
221/*
222 * Hook disconnection
223 */
224static int
225ng_UI_disconnect(hook_p hook)
226{
227	const priv_p priv = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
228
229	if (hook == priv->downlink)
230		priv->downlink = NULL;
231	else if (hook == priv->uplink)
232		priv->uplink = NULL;
233	else
234		panic("%s", __func__);
235	/*
236	 * If we are not already shutting down,
237	 * and we have no more hooks, then DO shut down.
238	 */
239	if ((NG_NODE_NUMHOOKS(NG_HOOK_NODE(hook)) == 0)
240	&& (NG_NODE_IS_VALID(NG_HOOK_NODE(hook)))) {
241			ng_rmnode_self(NG_HOOK_NODE(hook));
242	}
243	return (0);
244}
245
246