1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3 *
4 * Copyright (c) 1996 - 2001 Brian Somers <[email protected]>
5 * based on work by Toshiharu OHNO <[email protected]>
6 * Internet Initiative Japan, Inc (IIJ)
7 * All rights reserved.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 * notice, this list of conditions and the following disclaimer in the
16 * documentation and/or other materials provided with the distribution.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28 * SUCH DAMAGE.
29 *
30 */
31
32 #include <sys/cdefs.h>
33 __FBSDID("$FreeBSD$");
34
35 #include <sys/types.h>
36
37 #include <string.h>
38 #include <termios.h>
39
40 #include "layer.h"
41 #include "mbuf.h"
42 #include "log.h"
43 #include "defs.h"
44 #include "timer.h"
45 #include "fsm.h"
46 #include "lqr.h"
47 #include "hdlc.h"
48 #include "lcp.h"
49 #include "proto.h"
50 #include "async.h"
51 #include "throughput.h"
52 #include "ccp.h"
53 #include "link.h"
54 #include "descriptor.h"
55 #include "physical.h"
56
57 #define MODE_HUNT 0x01
58 #define MODE_ESC 0x02
59
60 void
async_Init(struct async * async)61 async_Init(struct async *async)
62 {
63 async_Setup(async);
64 memset(async->cfg.EscMap, '\0', sizeof async->cfg.EscMap);
65 }
66
67 void
async_Setup(struct async * async)68 async_Setup(struct async *async)
69 {
70 async->mode = MODE_HUNT;
71 async->length = 0;
72 async->my_accmap = async->his_accmap = 0xffffffff;
73 }
74
75 void
async_SetLinkParams(struct async * async,u_int32_t mymap,u_int32_t hismap)76 async_SetLinkParams(struct async *async, u_int32_t mymap, u_int32_t hismap)
77 {
78 async->my_accmap = mymap;
79 async->his_accmap = hismap | mymap;
80 }
81
82 /*
83 * Encode into async HDLC byte code
84 */
85 static void
async_Encode(struct async * async,u_char ** cp,u_char c,int proto)86 async_Encode(struct async *async, u_char **cp, u_char c, int proto)
87 {
88 u_char *wp;
89
90 wp = *cp;
91 if ((c < 0x20 && (proto == PROTO_LCP || (async->his_accmap & (1 << c))))
92 || (c == HDLC_ESC) || (c == HDLC_SYN)) {
93 *wp++ = HDLC_ESC;
94 c ^= HDLC_XOR;
95 }
96 if (async->cfg.EscMap[32] && async->cfg.EscMap[c >> 3] & (1 << (c & 7))) {
97 *wp++ = HDLC_ESC;
98 c ^= HDLC_XOR;
99 }
100 *wp++ = c;
101 *cp = wp;
102 }
103
104 static struct mbuf *
async_LayerPush(struct bundle * b __unused,struct link * l,struct mbuf * bp,int pri __unused,u_short * proto)105 async_LayerPush(struct bundle *b __unused, struct link *l, struct mbuf *bp,
106 int pri __unused, u_short *proto)
107 {
108 struct physical *p = link2physical(l);
109 u_char *cp, *sp, *ep;
110 struct mbuf *wp;
111 size_t oldcnt;
112 size_t cnt;
113
114 if (!p || m_length(bp) > HDLCSIZE) {
115 m_freem(bp);
116 return NULL;
117 }
118
119 oldcnt = m_length(bp);
120
121 cp = p->async.xbuff;
122 ep = cp + HDLCSIZE - 10;
123 wp = bp;
124 *cp++ = HDLC_SYN;
125 while (wp) {
126 sp = MBUF_CTOP(wp);
127 for (cnt = wp->m_len; cnt > 0; cnt--) {
128 async_Encode(&p->async, &cp, *sp++, *proto);
129 if (cp >= ep) {
130 m_freem(bp);
131 return NULL;
132 }
133 }
134 wp = wp->m_next;
135 }
136 *cp++ = HDLC_SYN;
137
138 cnt = cp - p->async.xbuff;
139 m_freem(bp);
140 bp = m_get(cnt, MB_ASYNCOUT);
141 memcpy(MBUF_CTOP(bp), p->async.xbuff, cnt);
142 bp->priv = cnt - oldcnt;
143 log_DumpBp(LogASYNC, "Write", bp);
144
145 return bp;
146 }
147
148 static struct mbuf *
async_Decode(struct async * async,u_char c)149 async_Decode(struct async *async, u_char c)
150 {
151 struct mbuf *bp;
152
153 if ((async->mode & MODE_HUNT) && c != HDLC_SYN)
154 return NULL;
155
156 switch (c) {
157 case HDLC_SYN:
158 async->mode &= ~MODE_HUNT;
159 if (async->length) { /* packet is ready. */
160 bp = m_get(async->length, MB_ASYNCIN);
161 mbuf_Write(bp, async->hbuff, async->length);
162 async->length = 0;
163 return bp;
164 }
165 break;
166 case HDLC_ESC:
167 if (!(async->mode & MODE_ESC)) {
168 async->mode |= MODE_ESC;
169 break;
170 }
171 /* FALLTHROUGH */
172 default:
173 if (async->length >= HDLCSIZE) {
174 /* packet is too large, discard it */
175 log_Printf(LogWARN, "Packet too large (%d), discarding.\n",
176 async->length);
177 async->length = 0;
178 async->mode = MODE_HUNT;
179 break;
180 }
181 if (async->mode & MODE_ESC) {
182 c ^= HDLC_XOR;
183 async->mode &= ~MODE_ESC;
184 }
185 async->hbuff[async->length++] = c;
186 break;
187 }
188 return NULL;
189 }
190
191 static struct mbuf *
async_LayerPull(struct bundle * b __unused,struct link * l,struct mbuf * bp,u_short * proto __unused)192 async_LayerPull(struct bundle *b __unused, struct link *l, struct mbuf *bp,
193 u_short *proto __unused)
194 {
195 struct mbuf *nbp, **last;
196 struct physical *p = link2physical(l);
197 u_char *ch;
198 size_t cnt;
199
200 if (!p) {
201 log_Printf(LogERROR, "Can't Pull an async packet from a logical link\n");
202 return bp;
203 }
204
205 last = &nbp;
206
207 log_DumpBp(LogASYNC, "Read", bp);
208 while (bp) {
209 ch = MBUF_CTOP(bp);
210 for (cnt = bp->m_len; cnt; cnt--) {
211 *last = async_Decode(&p->async, *ch++);
212 if (*last != NULL)
213 last = &(*last)->m_nextpkt;
214 }
215 bp = m_free(bp);
216 }
217
218 return nbp;
219 }
220
221 struct layer asynclayer =
222 { LAYER_ASYNC, "async", async_LayerPush, async_LayerPull };
223