ng_UI.c revision 69922 
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 69922 2000-12-12 18:52:14Z 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_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	int     error;
108
109	/* Allocate private structure */
110	MALLOC(priv, priv_p, sizeof(*priv), M_NETGRAPH, M_NOWAIT | M_ZERO);
111	if (priv == NULL)
112		return (ENOMEM);
113
114	/* Call generic node constructor */
115	if ((error = ng_make_node_common(&typestruct, nodep))) {
116		FREE(priv, M_NETGRAPH);
117		return (error);
118	}
119	(*nodep)->private = priv;
120
121	/* Done */
122	return (0);
123}
124
125/*
126 * Give our ok for a hook to be added
127 */
128static int
129ng_UI_newhook(node_p node, hook_p hook, const char *name)
130{
131	const priv_p priv = node->private;
132
133	if (!strcmp(name, NG_UI_HOOK_DOWNSTREAM)) {
134		if (priv->downlink)
135			return (EISCONN);
136		priv->downlink = hook;
137	} else if (!strcmp(name, NG_UI_HOOK_UPSTREAM)) {
138		if (priv->uplink)
139			return (EISCONN);
140		priv->uplink = hook;
141	} else
142		return (EINVAL);
143	return (0);
144}
145
146/*
147 * Receive a control message
148 */
149static int
150ng_UI_rcvmsg(node_p node, struct ng_mesg *msg,
151	     const char *raddr, struct ng_mesg **rp, hook_p lasthook)
152{
153	const priv_p priv = node->private;
154
155	if ((msg->header.typecookie == NGM_FLOW_COOKIE) && lasthook)  {
156		if (lasthook == priv->downlink) {
157			if (priv->uplink) {
158				return (ng_send_msg(node, msg, NULL,
159					priv->uplink, raddr, rp));
160			}
161		} else {
162			if (priv->downlink) {
163				return (ng_send_msg(node, msg, NULL,
164					priv->downlink, raddr, rp));
165			}
166		}
167	}
168
169	FREE(msg, M_NETGRAPH);
170	return (EINVAL);
171}
172
173#define MAX_ENCAPS_HDR	1
174#define ERROUT(x)	do { error = (x); goto done; } while (0)
175
176/*
177 * Receive a data frame
178 */
179static int
180ng_UI_rcvdata(hook_p hook, struct mbuf *m, meta_p meta,
181		struct mbuf **ret_m, meta_p *ret_meta,  struct ng_mesg **resp)
182{
183	const node_p node = hook->node;
184	const priv_p priv = node->private;
185	int error = 0;
186
187	if (hook == priv->downlink) {
188		u_char *start, *ptr;
189
190		if (!m || (m->m_len < MAX_ENCAPS_HDR
191		    && !(m = m_pullup(m, MAX_ENCAPS_HDR))))
192			ERROUT(ENOBUFS);
193		ptr = start = mtod(m, u_char *);
194
195		/* Must be UI frame */
196		if (*ptr++ != HDLC_UI)
197			ERROUT(0);
198
199		m_adj(m, ptr - start);
200		NG_SEND_DATA(error, priv->uplink, m, meta);	/* m -> NULL */
201	} else if (hook == priv->uplink) {
202		M_PREPEND(m, 1, M_DONTWAIT);	/* Prepend IP NLPID */
203		if (!m)
204			ERROUT(ENOBUFS);
205		mtod(m, u_char *)[0] = HDLC_UI;
206		NG_SEND_DATA(error, priv->downlink, m, meta);	/* m -> NULL */
207	} else
208		panic(__FUNCTION__);
209
210done:
211	NG_FREE_DATA(m, meta);	/* does nothing if m == NULL */
212	return (error);
213}
214
215/*
216 * Shutdown node
217 */
218static int
219ng_UI_rmnode(node_p node)
220{
221	const priv_p priv = node->private;
222
223	/* Take down netgraph node */
224	node->flags |= NG_INVALID;
225	ng_cutlinks(node);
226	ng_unname(node);
227	bzero(priv, sizeof(*priv));
228	FREE(priv, M_NETGRAPH);
229	node->private = NULL;
230	ng_unref(node);
231	return (0);
232}
233
234/*
235 * Hook disconnection
236 */
237static int
238ng_UI_disconnect(hook_p hook)
239{
240	const priv_p priv = hook->node->private;
241
242	if (hook->node->numhooks == 0)
243		ng_rmnode(hook->node);
244	else if (hook == priv->downlink)
245		priv->downlink = NULL;
246	else if (hook == priv->uplink)
247		priv->uplink = NULL;
248	else
249		panic(__FUNCTION__);
250	return (0);
251}
252
253