ng_UI.c revision 54249 
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@whistle.com>
38 *
39 * $FreeBSD: head/sys/netgraph/ng_UI.c 54249 1999-12-07 05:50:48Z 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_rmnode;
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_VERSION,
81	NG_UI_NODE_TYPE,
82	NULL,
83	ng_UI_constructor,
84	ng_UI_rcvmsg,
85	ng_UI_rmnode,
86	ng_UI_newhook,
87	NULL,
88	NULL,
89	ng_UI_rcvdata,
90	ng_UI_rcvdata,
91	ng_UI_disconnect,
92	NULL
93};
94NETGRAPH_INIT(UI, &typestruct);
95
96/************************************************************************
97			NETGRAPH NODE STUFF
98 ************************************************************************/
99
100/*
101 * Create a newborn node. We start with an implicit reference.
102 */
103
104static int
105ng_UI_constructor(node_p *nodep)
106{
107	priv_p  priv;
108	int     error;
109
110	/* Allocate private structure */
111	MALLOC(priv, priv_p, sizeof(*priv), M_NETGRAPH, M_WAITOK);
112	if (priv == NULL)
113		return (ENOMEM);
114	bzero(priv, sizeof(*priv));
115
116	/* Call generic node constructor */
117	if ((error = ng_make_node_common(&typestruct, nodep))) {
118		FREE(priv, M_NETGRAPH);
119		return (error);
120	}
121	(*nodep)->private = priv;
122
123	/* Done */
124	return (0);
125}
126
127/*
128 * Give our ok for a hook to be added
129 */
130static int
131ng_UI_newhook(node_p node, hook_p hook, const char *name)
132{
133	const priv_p priv = node->private;
134
135	if (!strcmp(name, NG_UI_HOOK_DOWNSTREAM)) {
136		if (priv->downlink)
137			return (EISCONN);
138		priv->downlink = hook;
139	} else if (!strcmp(name, NG_UI_HOOK_UPSTREAM)) {
140		if (priv->uplink)
141			return (EISCONN);
142		priv->uplink = hook;
143	} else
144		return (EINVAL);
145	return (0);
146}
147
148/*
149 * Receive a control message
150 */
151static int
152ng_UI_rcvmsg(node_p node, struct ng_mesg *msg,
153	     const char *raddr, struct ng_mesg **rp)
154{
155	FREE(msg, M_NETGRAPH);
156	return (EINVAL);
157}
158
159#define MAX_ENCAPS_HDR	1
160#define ERROUT(x)	do { error = (x); goto done; } while (0)
161
162/*
163 * Receive a data frame
164 */
165static int
166ng_UI_rcvdata(hook_p hook, struct mbuf *m, meta_p meta)
167{
168	const node_p node = hook->node;
169	const priv_p priv = node->private;
170	int error = 0;
171
172	if (hook == priv->downlink) {
173		u_char *start, *ptr;
174
175		if (!m || (m->m_len < MAX_ENCAPS_HDR
176		    && !(m = m_pullup(m, MAX_ENCAPS_HDR))))
177			ERROUT(ENOBUFS);
178		ptr = start = mtod(m, u_char *);
179
180		/* Must be UI frame */
181		if (*ptr++ != HDLC_UI)
182			ERROUT(0);
183
184		m_adj(m, ptr - start);
185		NG_SEND_DATA(error, priv->uplink, m, meta);	/* m -> NULL */
186	} else if (hook == priv->uplink) {
187		M_PREPEND(m, 1, M_DONTWAIT);	/* Prepend IP NLPID */
188		if (!m)
189			ERROUT(ENOBUFS);
190		mtod(m, u_char *)[0] = HDLC_UI;
191		NG_SEND_DATA(error, priv->downlink, m, meta);	/* m -> NULL */
192	} else
193		panic(__FUNCTION__);
194
195done:
196	NG_FREE_DATA(m, meta);	/* does nothing if m == NULL */
197	return (error);
198}
199
200/*
201 * Shutdown node
202 */
203static int
204ng_UI_rmnode(node_p node)
205{
206	const priv_p priv = node->private;
207
208	/* Take down netgraph node */
209	node->flags |= NG_INVALID;
210	ng_cutlinks(node);
211	ng_unname(node);
212	bzero(priv, sizeof(*priv));
213	FREE(priv, M_NETGRAPH);
214	node->private = NULL;
215	ng_unref(node);
216	return (0);
217}
218
219/*
220 * Hook disconnection
221 */
222static int
223ng_UI_disconnect(hook_p hook)
224{
225	const priv_p priv = hook->node->private;
226
227	if (hook->node->numhooks == 0)
228		ng_rmnode(hook->node);
229	else if (hook == priv->downlink)
230		priv->downlink = NULL;
231	else if (hook == priv->uplink)
232		priv->uplink = NULL;
233	else
234		panic(__FUNCTION__);
235	return (0);
236}
237
238