ng_UI.c revision 70784 
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 70784 2001-01-08 05:34:06Z 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 node)
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	NG_NODE_SET_PRIVATE(node, 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 = NG_NODE_PRIVATE(node);
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 = NG_NODE_PRIVATE(node);
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_ITEM_HOOK(error, item, priv->uplink);
153				return (error);
154			}
155		} else {
156			if (priv->downlink) {
157				NG_FWD_ITEM_HOOK(error, item, priv->downlink);
158				return (error);
159			}
160		}
161	}
162
163	NG_FREE_ITEM(item);
164	return (EINVAL);
165}
166
167#define MAX_ENCAPS_HDR	1
168#define ERROUT(x)	do { error = (x); goto done; } while (0)
169
170/*
171 * Receive a data frame
172 */
173static int
174ng_UI_rcvdata(hook_p hook, item_p item)
175{
176	const node_p node = NG_HOOK_NODE(hook);
177	const priv_p priv = NG_NODE_PRIVATE(node);
178	struct mbuf *m;
179	int error = 0;
180
181	NGI_GET_M(item, m);
182	if (hook == priv->downlink) {
183		u_char *start, *ptr;
184
185		if (!m || (m->m_len < MAX_ENCAPS_HDR
186		    && !(m = m_pullup(m, MAX_ENCAPS_HDR))))
187			ERROUT(ENOBUFS);
188		ptr = start = mtod(m, u_char *);
189
190		/* Must be UI frame */
191		if (*ptr++ != HDLC_UI)
192			ERROUT(0);
193
194		m_adj(m, ptr - start);
195		NG_FWD_NEW_DATA(error, item, priv->uplink, m);	/* m -> NULL */
196	} else if (hook == priv->uplink) {
197		M_PREPEND(m, 1, M_DONTWAIT);	/* Prepend IP NLPID */
198		if (!m)
199			ERROUT(ENOBUFS);
200		mtod(m, u_char *)[0] = HDLC_UI;
201		NG_FWD_NEW_DATA(error, item, priv->downlink, m);	/* m -> NULL */
202	} else
203		panic(__FUNCTION__);
204
205done:
206	NG_FREE_M(m);	/* does nothing if m == NULL */
207	if (item)
208		NG_FREE_ITEM(item);
209	return (error);
210}
211
212/*
213 * Shutdown node
214 */
215static int
216ng_UI_shutdown(node_p node)
217{
218	const priv_p priv = NG_NODE_PRIVATE(node);
219
220	/* Take down netgraph node */
221	FREE(priv, M_NETGRAPH);
222	NG_NODE_SET_PRIVATE(node, NULL);
223	NG_NODE_UNREF(node);
224	return (0);
225}
226
227/*
228 * Hook disconnection
229 */
230static int
231ng_UI_disconnect(hook_p hook)
232{
233	const priv_p priv = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
234
235	if (hook == priv->downlink)
236		priv->downlink = NULL;
237	else if (hook == priv->uplink)
238		priv->uplink = NULL;
239	else
240		panic(__FUNCTION__);
241	/*
242	 * If we are not already shutting down,
243	 * and we have no more hooks, then DO shut down.
244	 */
245	if ((NG_NODE_NUMHOOKS(NG_HOOK_NODE(hook)) == 0)
246	&& (NG_NODE_IS_VALID(NG_HOOK_NODE(hook)))) {
247			ng_rmnode_self(NG_HOOK_NODE(hook));
248	}
249	return (0);
250}
251
252