ng_UI.c revision 70700 
1
2/*
3 * ng_UI.c
4 *
5 * Copyright (c) 1996-1999 Whistle Communications, Inc.
6 * All rights reserved.
7 *
8 * Subject to the following obligations and disclaimer of warranty, use and
9 * redistribution of this software, in source or object code forms, with or
10 * without modifications are expressly permitted by Whistle Communications;
11 * provided, however, that:
12 * 1. Any and all reproductions of the source or object code must include the
13 *    copyright notice above and the following disclaimer of warranties; and
14 * 2. No rights are granted, in any manner or form, to use Whistle
15 *    Communications, Inc. trademarks, including the mark "WHISTLE
16 *    COMMUNICATIONS" on advertising, endorsements, or otherwise except as
17 *    such appears in the above copyright notice or in the software.
18 *
19 * THIS SOFTWARE IS BEING PROVIDED BY WHISTLE COMMUNICATIONS "AS IS", AND
20 * TO THE MAXIMUM EXTENT PERMITTED BY LAW, WHISTLE COMMUNICATIONS MAKES NO
21 * REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED, REGARDING THIS SOFTWARE,
22 * INCLUDING WITHOUT LIMITATION, ANY AND ALL IMPLIED WARRANTIES OF
23 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT.
24 * WHISTLE COMMUNICATIONS DOES NOT WARRANT, GUARANTEE, OR MAKE ANY
25 * REPRESENTATIONS REGARDING THE USE OF, OR THE RESULTS OF THE USE OF THIS
26 * SOFTWARE IN TERMS OF ITS CORRECTNESS, ACCURACY, RELIABILITY OR OTHERWISE.
27 * IN NO EVENT SHALL WHISTLE COMMUNICATIONS BE LIABLE FOR ANY DAMAGES
28 * RESULTING FROM OR ARISING OUT OF ANY USE OF THIS SOFTWARE, INCLUDING
29 * WITHOUT LIMITATION, ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
30 * PUNITIVE, OR CONSEQUENTIAL DAMAGES, PROCUREMENT OF SUBSTITUTE GOODS OR
31 * SERVICES, LOSS OF USE, DATA OR PROFITS, HOWEVER CAUSED AND UNDER ANY
32 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
33 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
34 * THIS SOFTWARE, EVEN IF WHISTLE COMMUNICATIONS IS ADVISED OF THE POSSIBILITY
35 * OF SUCH DAMAGE.
36 *
37 * Author: Julian Elischer <julian@freebsd.org>
38 *
39 * $FreeBSD: head/sys/netgraph/ng_UI.c 70700 2001-01-06 00:46:47Z julian $
40 * $Whistle: ng_UI.c,v 1.14 1999/11/01 09:24:51 julian Exp $
41 */
42
43#include <sys/param.h>
44#include <sys/systm.h>
45#include <sys/errno.h>
46#include <sys/kernel.h>
47#include <sys/malloc.h>
48#include <sys/mbuf.h>
49#include <sys/errno.h>
50
51
52#include <netgraph/ng_message.h>
53#include <netgraph/netgraph.h>
54#include <netgraph/ng_UI.h>
55
56/*
57 * DEFINITIONS
58 */
59
60/* Everything, starting with sdlc on has defined UI as 0x03 */
61#define HDLC_UI	0x03
62
63/* Node private data */
64struct ng_UI_private {
65	hook_p  downlink;
66	hook_p  uplink;
67};
68typedef struct ng_UI_private *priv_p;
69
70/* Netgraph node methods */
71static ng_constructor_t	ng_UI_constructor;
72static ng_rcvmsg_t	ng_UI_rcvmsg;
73static ng_shutdown_t	ng_UI_shutdown;
74static ng_newhook_t	ng_UI_newhook;
75static ng_rcvdata_t	ng_UI_rcvdata;
76static ng_disconnect_t	ng_UI_disconnect;
77
78/* Node type descriptor */
79static struct ng_type typestruct = {
80	NG_ABI_VERSION,
81	NG_UI_NODE_TYPE,
82	NULL,
83	ng_UI_constructor,
84	ng_UI_rcvmsg,
85	ng_UI_shutdown,
86	ng_UI_newhook,
87	NULL,
88	NULL,
89	ng_UI_rcvdata,
90	ng_UI_disconnect,
91	NULL
92};
93NETGRAPH_INIT(UI, &typestruct);
94
95/************************************************************************
96			NETGRAPH NODE STUFF
97 ************************************************************************/
98
99/*
100 * Create a newborn node. We start with an implicit reference.
101 */
102
103static int
104ng_UI_constructor(node_p nodep)
105{
106	priv_p  priv;
107
108	/* Allocate private structure */
109	MALLOC(priv, priv_p, sizeof(*priv), M_NETGRAPH, M_NOWAIT | M_ZERO);
110	if (priv == NULL) {
111		return (ENOMEM);
112	}
113	nodep->private = priv;
114	return (0);
115}
116
117/*
118 * Give our ok for a hook to be added
119 */
120static int
121ng_UI_newhook(node_p node, hook_p hook, const char *name)
122{
123	const priv_p priv = node->private;
124
125	if (!strcmp(name, NG_UI_HOOK_DOWNSTREAM)) {
126		if (priv->downlink)
127			return (EISCONN);
128		priv->downlink = hook;
129	} else if (!strcmp(name, NG_UI_HOOK_UPSTREAM)) {
130		if (priv->uplink)
131			return (EISCONN);
132		priv->uplink = hook;
133	} else
134		return (EINVAL);
135	return (0);
136}
137
138/*
139 * Receive a control message
140 */
141static int
142ng_UI_rcvmsg(node_p node, item_p item, hook_p lasthook)
143{
144	int	error;
145	const priv_p priv = node->private;
146	struct ng_mesg *msg;
147
148	msg = NGI_MSG(item); /* only peeking */
149	if ((msg->header.typecookie == NGM_FLOW_COOKIE) && lasthook)  {
150		if (lasthook == priv->downlink) {
151			if (priv->uplink) {
152				NG_FWD_MSG_HOOK(error, node, item,
153					priv->uplink, 0);
154				return (error);
155			}
156		} else {
157			if (priv->downlink) {
158				NG_FWD_MSG_HOOK(error, node, item,
159					priv->downlink, 0);
160				return (error);
161			}
162		}
163	}
164
165	NG_FREE_MSG(msg);
166	return (EINVAL);
167}
168
169#define MAX_ENCAPS_HDR	1
170#define ERROUT(x)	do { error = (x); goto done; } while (0)
171
172/*
173 * Receive a data frame
174 */
175static int
176ng_UI_rcvdata(hook_p hook, item_p item)
177{
178	const node_p node = hook->node;
179	const priv_p priv = node->private;
180	struct mbuf *m;
181	int error = 0;
182
183	NGI_GET_M(item, m);
184	if (hook == priv->downlink) {
185		u_char *start, *ptr;
186
187		if (!m || (m->m_len < MAX_ENCAPS_HDR
188		    && !(m = m_pullup(m, MAX_ENCAPS_HDR))))
189			ERROUT(ENOBUFS);
190		ptr = start = mtod(m, u_char *);
191
192		/* Must be UI frame */
193		if (*ptr++ != HDLC_UI)
194			ERROUT(0);
195
196		m_adj(m, ptr - start);
197		NG_FWD_NEW_DATA(error, item, priv->uplink, m);	/* m -> NULL */
198	} else if (hook == priv->uplink) {
199		M_PREPEND(m, 1, M_DONTWAIT);	/* Prepend IP NLPID */
200		if (!m)
201			ERROUT(ENOBUFS);
202		mtod(m, u_char *)[0] = HDLC_UI;
203		NG_FWD_NEW_DATA(error, item, priv->downlink, m);	/* m -> NULL */
204	} else
205		panic(__FUNCTION__);
206
207done:
208	NG_FREE_M(m);	/* does nothing if m == NULL */
209	if (item)
210		NG_FREE_ITEM(item);
211	return (error);
212}
213
214/*
215 * Shutdown node
216 */
217static int
218ng_UI_shutdown(node_p node)
219{
220	const priv_p priv = node->private;
221
222	/* Take down netgraph node */
223	FREE(priv, M_NETGRAPH);
224	node->private = NULL;
225	ng_unref(node);
226	return (0);
227}
228
229/*
230 * Hook disconnection
231 */
232static int
233ng_UI_disconnect(hook_p hook)
234{
235	const priv_p priv = hook->node->private;
236
237	if (hook == priv->downlink)
238		priv->downlink = NULL;
239	else if (hook == priv->uplink)
240		priv->uplink = NULL;
241	else
242		panic(__FUNCTION__);
243	/*
244	 * If we are not already shutting down,
245	 * and we have no more hooks, then DO shut down.
246	 */
247	if ((hook->node->numhooks == 0)
248	&& ((hook->node->flags & NG_INVALID) == 0)) {
249			ng_rmnode_self(hook->node);
250	}
251	return (0);
252}
253
254