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 * $Whistle: ng_UI.c,v 1.14 1999/11/01 09:24:51 julian Exp $
40 */
41
42 #include <sys/param.h>
43 #include <sys/systm.h>
44 #include <sys/errno.h>
45 #include <sys/kernel.h>
46 #include <sys/malloc.h>
47 #include <sys/mbuf.h>
48 #include <sys/errno.h>
49
50 #include <netgraph/ng_message.h>
51 #include <netgraph/netgraph.h>
52 #include <netgraph/ng_UI.h>
53
54 /*
55 * DEFINITIONS
56 */
57
58 /* Everything, starting with sdlc on has defined UI as 0x03 */
59 #define HDLC_UI 0x03
60
61 /* Node private data */
62 struct ng_UI_private {
63 hook_p downlink;
64 hook_p uplink;
65 };
66 typedef struct ng_UI_private *priv_p;
67
68 /* Netgraph node methods */
69 static ng_constructor_t ng_UI_constructor;
70 static ng_rcvmsg_t ng_UI_rcvmsg;
71 static ng_shutdown_t ng_UI_shutdown;
72 static ng_newhook_t ng_UI_newhook;
73 static ng_rcvdata_t ng_UI_rcvdata;
74 static ng_disconnect_t ng_UI_disconnect;
75
76 /* Node type descriptor */
77 static struct ng_type typestruct = {
78 .version = NG_ABI_VERSION,
79 .name = NG_UI_NODE_TYPE,
80 .constructor = ng_UI_constructor,
81 .rcvmsg = ng_UI_rcvmsg,
82 .shutdown = ng_UI_shutdown,
83 .newhook = ng_UI_newhook,
84 .rcvdata = ng_UI_rcvdata,
85 .disconnect = ng_UI_disconnect,
86 };
87 NETGRAPH_INIT(UI, &typestruct);
88
89 /************************************************************************
90 NETGRAPH NODE STUFF
91 ************************************************************************/
92
93 /*
94 * Create a newborn node. We start with an implicit reference.
95 */
96
97 static int
ng_UI_constructor(node_p node)98 ng_UI_constructor(node_p node)
99 {
100 priv_p priv;
101
102 /* Allocate private structure */
103 priv = malloc(sizeof(*priv), M_NETGRAPH, M_WAITOK | M_ZERO);
104 NG_NODE_SET_PRIVATE(node, priv);
105 return (0);
106 }
107
108 /*
109 * Give our ok for a hook to be added
110 */
111 static int
ng_UI_newhook(node_p node,hook_p hook,const char * name)112 ng_UI_newhook(node_p node, hook_p hook, const char *name)
113 {
114 const priv_p priv = NG_NODE_PRIVATE(node);
115
116 if (!strcmp(name, NG_UI_HOOK_DOWNSTREAM)) {
117 if (priv->downlink)
118 return (EISCONN);
119 priv->downlink = hook;
120 } else if (!strcmp(name, NG_UI_HOOK_UPSTREAM)) {
121 if (priv->uplink)
122 return (EISCONN);
123 priv->uplink = hook;
124 } else
125 return (EINVAL);
126 return (0);
127 }
128
129 /*
130 * Receive a control message
131 */
132 static int
ng_UI_rcvmsg(node_p node,item_p item,hook_p lasthook)133 ng_UI_rcvmsg(node_p node, item_p item, hook_p lasthook)
134 {
135 int error;
136 const priv_p priv = NG_NODE_PRIVATE(node);
137 struct ng_mesg *msg;
138
139 msg = NGI_MSG(item); /* only peeking */
140 if ((msg->header.typecookie == NGM_FLOW_COOKIE) && lasthook) {
141 if (lasthook == priv->downlink) {
142 if (priv->uplink) {
143 NG_FWD_ITEM_HOOK(error, item, priv->uplink);
144 return (error);
145 }
146 } else {
147 if (priv->downlink) {
148 NG_FWD_ITEM_HOOK(error, item, priv->downlink);
149 return (error);
150 }
151 }
152 }
153
154 NG_FREE_ITEM(item);
155 return (EINVAL);
156 }
157
158 #define MAX_ENCAPS_HDR 1
159 #define ERROUT(x) do { error = (x); goto done; } while (0)
160
161 /*
162 * Receive a data frame
163 */
164 static int
ng_UI_rcvdata(hook_p hook,item_p item)165 ng_UI_rcvdata(hook_p hook, item_p item)
166 {
167 const node_p node = NG_HOOK_NODE(hook);
168 const priv_p priv = NG_NODE_PRIVATE(node);
169 struct mbuf *m;
170 int error = 0;
171
172 NGI_GET_M(item, m);
173 if (hook == priv->downlink) {
174 u_char *start, *ptr;
175
176 if (m->m_len < MAX_ENCAPS_HDR
177 && !(m = m_pullup(m, MAX_ENCAPS_HDR)))
178 ERROUT(ENOBUFS);
179 ptr = start = mtod(m, u_char *);
180
181 /* Must be UI frame */
182 if (*ptr++ != HDLC_UI)
183 ERROUT(0);
184
185 m_adj(m, ptr - start);
186 NG_FWD_NEW_DATA(error, item, priv->uplink, m); /* m -> NULL */
187 } else if (hook == priv->uplink) {
188 M_PREPEND(m, 1, M_NOWAIT); /* Prepend IP NLPID */
189 if (!m)
190 ERROUT(ENOBUFS);
191 mtod(m, u_char *)[0] = HDLC_UI;
192 NG_FWD_NEW_DATA(error, item, priv->downlink, m); /* m -> NULL */
193 } else
194 panic("%s", __func__);
195
196 done:
197 NG_FREE_M(m); /* does nothing if m == NULL */
198 if (item)
199 NG_FREE_ITEM(item);
200 return (error);
201 }
202
203 /*
204 * Shutdown node
205 */
206 static int
ng_UI_shutdown(node_p node)207 ng_UI_shutdown(node_p node)
208 {
209 const priv_p priv = NG_NODE_PRIVATE(node);
210
211 /* Take down netgraph node */
212 free(priv, M_NETGRAPH);
213 NG_NODE_SET_PRIVATE(node, NULL);
214 NG_NODE_UNREF(node);
215 return (0);
216 }
217
218 /*
219 * Hook disconnection
220 */
221 static int
ng_UI_disconnect(hook_p hook)222 ng_UI_disconnect(hook_p hook)
223 {
224 const priv_p priv = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
225
226 if (hook == priv->downlink)
227 priv->downlink = NULL;
228 else if (hook == priv->uplink)
229 priv->uplink = NULL;
230 else
231 panic("%s", __func__);
232 /*
233 * If we are not already shutting down,
234 * and we have no more hooks, then DO shut down.
235 */
236 if ((NG_NODE_NUMHOOKS(NG_HOOK_NODE(hook)) == 0)
237 && (NG_NODE_IS_VALID(NG_HOOK_NODE(hook)))) {
238 ng_rmnode_self(NG_HOOK_NODE(hook));
239 }
240 return (0);
241 }
242