1 /*        $NetBSD: sir.c,v 1.6 2013/05/27 16:23:20 kiyohara Exp $     */
2 
3 /*
4  * Copyright (c) 2001 The NetBSD Foundation, Inc.
5  * All rights reserved.
6  *
7  * This code is derived from software contributed to The NetBSD Foundation
8  * by Lennart Augustsson (lennart@augustsson.net) and Tommy Bohlin
9  * (tommy@gatespace.com).
10  *
11  * Redistribution and use in source and binary forms, with or without
12  * modification, are permitted provided that the following conditions
13  * are met:
14  * 1. Redistributions of source code must retain the above copyright
15  *    notice, this list of conditions and the following disclaimer.
16  * 2. Redistributions in binary form must reproduce the above copyright
17  *    notice, this list of conditions and the following disclaimer in the
18  *    documentation and/or other materials provided with the distribution.
19  *
20  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
21  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
22  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
23  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
24  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
25  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
26  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
27  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
28  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
29  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
30  * POSSIBILITY OF SUCH DAMAGE.
31  */
32 
33 /*
34  * Framing originally written by Tommy Bohlin.
35  */
36 
37 #include <sys/cdefs.h>
38 __KERNEL_RCSID(0, "$NetBSD: sir.c,v 1.6 2013/05/27 16:23:20 kiyohara Exp $");
39 
40 #include <sys/param.h>
41 #include <sys/conf.h>
42 #include <sys/systm.h>
43 
44 #include <dev/ir/sir.h>
45 
46 /*
47  * CRC computation table
48  */
49 const uint16_t irda_fcstab[] = {
50           0x0000, 0x1189, 0x2312, 0x329b, 0x4624, 0x57ad, 0x6536, 0x74bf,
51           0x8c48, 0x9dc1, 0xaf5a, 0xbed3, 0xca6c, 0xdbe5, 0xe97e, 0xf8f7,
52           0x1081, 0x0108, 0x3393, 0x221a, 0x56a5, 0x472c, 0x75b7, 0x643e,
53           0x9cc9, 0x8d40, 0xbfdb, 0xae52, 0xdaed, 0xcb64, 0xf9ff, 0xe876,
54           0x2102, 0x308b, 0x0210, 0x1399, 0x6726, 0x76af, 0x4434, 0x55bd,
55           0xad4a, 0xbcc3, 0x8e58, 0x9fd1, 0xeb6e, 0xfae7, 0xc87c, 0xd9f5,
56           0x3183, 0x200a, 0x1291, 0x0318, 0x77a7, 0x662e, 0x54b5, 0x453c,
57           0xbdcb, 0xac42, 0x9ed9, 0x8f50, 0xfbef, 0xea66, 0xd8fd, 0xc974,
58           0x4204, 0x538d, 0x6116, 0x709f, 0x0420, 0x15a9, 0x2732, 0x36bb,
59           0xce4c, 0xdfc5, 0xed5e, 0xfcd7, 0x8868, 0x99e1, 0xab7a, 0xbaf3,
60           0x5285, 0x430c, 0x7197, 0x601e, 0x14a1, 0x0528, 0x37b3, 0x263a,
61           0xdecd, 0xcf44, 0xfddf, 0xec56, 0x98e9, 0x8960, 0xbbfb, 0xaa72,
62           0x6306, 0x728f, 0x4014, 0x519d, 0x2522, 0x34ab, 0x0630, 0x17b9,
63           0xef4e, 0xfec7, 0xcc5c, 0xddd5, 0xa96a, 0xb8e3, 0x8a78, 0x9bf1,
64           0x7387, 0x620e, 0x5095, 0x411c, 0x35a3, 0x242a, 0x16b1, 0x0738,
65           0xffcf, 0xee46, 0xdcdd, 0xcd54, 0xb9eb, 0xa862, 0x9af9, 0x8b70,
66           0x8408, 0x9581, 0xa71a, 0xb693, 0xc22c, 0xd3a5, 0xe13e, 0xf0b7,
67           0x0840, 0x19c9, 0x2b52, 0x3adb, 0x4e64, 0x5fed, 0x6d76, 0x7cff,
68           0x9489, 0x8500, 0xb79b, 0xa612, 0xd2ad, 0xc324, 0xf1bf, 0xe036,
69           0x18c1, 0x0948, 0x3bd3, 0x2a5a, 0x5ee5, 0x4f6c, 0x7df7, 0x6c7e,
70           0xa50a, 0xb483, 0x8618, 0x9791, 0xe32e, 0xf2a7, 0xc03c, 0xd1b5,
71           0x2942, 0x38cb, 0x0a50, 0x1bd9, 0x6f66, 0x7eef, 0x4c74, 0x5dfd,
72           0xb58b, 0xa402, 0x9699, 0x8710, 0xf3af, 0xe226, 0xd0bd, 0xc134,
73           0x39c3, 0x284a, 0x1ad1, 0x0b58, 0x7fe7, 0x6e6e, 0x5cf5, 0x4d7c,
74           0xc60c, 0xd785, 0xe51e, 0xf497, 0x8028, 0x91a1, 0xa33a, 0xb2b3,
75           0x4a44, 0x5bcd, 0x6956, 0x78df, 0x0c60, 0x1de9, 0x2f72, 0x3efb,
76           0xd68d, 0xc704, 0xf59f, 0xe416, 0x90a9, 0x8120, 0xb3bb, 0xa232,
77           0x5ac5, 0x4b4c, 0x79d7, 0x685e, 0x1ce1, 0x0d68, 0x3ff3, 0x2e7a,
78           0xe70e, 0xf687, 0xc41c, 0xd595, 0xa12a, 0xb0a3, 0x8238, 0x93b1,
79           0x6b46, 0x7acf, 0x4854, 0x59dd, 0x2d62, 0x3ceb, 0x0e70, 0x1ff9,
80           0xf78f, 0xe606, 0xd49d, 0xc514, 0xb1ab, 0xa022, 0x92b9, 0x8330,
81           0x7bc7, 0x6a4e, 0x58d5, 0x495c, 0x3de3, 0x2c6a, 0x1ef1, 0x0f78
82 };
83 
84 #define MAX_IRDA_FRAME 5000   /* XXX what is it? */
85 
86 #define PUTC(c) if (p < end) *p++ = (c)
87 #define PUTESC(c) \
88           if (c == SIR_BOF || c == SIR_EOF || c == SIR_CE) { \
89                     PUTC(SIR_CE); \
90                     PUTC(SIR_ESC_BIT^c); \
91           } else { \
92                     PUTC(c); \
93           }
94 
95 #define CHUNK 512
96 
97 int
irda_sir_frame(uint8_t * obuf,u_int maxlen,struct uio * uio,u_int ebofs)98 irda_sir_frame(uint8_t *obuf, u_int maxlen, struct uio *uio, u_int ebofs)
99 {
100           uint8_t ibuf[CHUNK];
101           uint8_t *p, *end, *cp;
102           size_t n;
103           int error;
104           int i;
105           int c;
106           uint16_t ofcs;
107 
108           p = obuf;
109           end = p + maxlen;
110 
111           for (i = 0; i < ebofs; i++)
112                     PUTC(SIR_EXTRA_BOF);
113           PUTC(SIR_BOF);
114 
115           ofcs = INITFCS;
116           while (uio->uio_resid > 0) {
117                     n = uio->uio_resid;
118                     if (n > CHUNK)
119                               n = CHUNK;
120                     error = uiomove(ibuf, n, uio);
121                     if (error)
122                               return (-error);
123 
124                     cp = ibuf;
125                     while (n-- > 0) {
126                               c = *cp++;
127                               ofcs = updateFCS(ofcs, c);
128                               PUTESC(c);
129                     }
130           }
131 
132           ofcs = ~ofcs;
133           c = ofcs & 0xff;
134           PUTESC(c);
135           c = (ofcs >> 8) & 0xff;
136           PUTESC(c);
137           PUTC(SIR_EOF);
138 
139           if (p < end)
140                     return (p - obuf);
141           else
142                     return (-EINVAL);
143 }
144 
145 void
deframe_init(struct framestate * fstate,uint8_t * buf,size_t buflen)146 deframe_init(struct framestate *fstate, uint8_t *buf, size_t buflen)
147 {
148 
149           fstate->buffer = buf;
150           fstate->buflen = buflen;
151 
152           deframe_clear(fstate);
153 }
154 
155 void
deframe_clear(struct framestate * fstate)156 deframe_clear(struct framestate *fstate)
157 {
158 
159           fstate->bufindex = 0;
160           fstate->fsmstate = FSTATE_END_OF_FRAME;
161           fstate->escaped = 0;
162 }
163 
164 enum frameresult
deframe_process(struct framestate * fstate,uint8_t const ** bptr,size_t * blen)165 deframe_process(struct framestate *fstate, uint8_t const **bptr, size_t *blen)
166 {
167           uint8_t const *cptr;
168           size_t ibuflen, obufindex, obuflen;
169           enum framefsmstate fsmstate;
170           enum frameresult result;
171 
172           cptr = *bptr;
173           fsmstate = fstate->fsmstate;
174           obufindex = fstate->bufindex;
175           obuflen = fstate->buflen;
176           ibuflen = *blen;
177 
178           while (ibuflen-- > 0) {
179                     uint8_t chr;
180 
181                     chr = *cptr++;
182 
183                     if (fstate->escaped) {
184                               fstate->escaped = 0;
185                               chr ^= SIR_ESC_BIT;
186                     } else if (chr == SIR_CE) {
187                               fstate->escaped = 1;
188                               continue;
189                     }
190 
191                     switch (fsmstate) {
192                     case FSTATE_IN_DATA:
193                               if (chr == SIR_EOF) {
194                                         fsmstate = FSTATE_IN_END;
195                                         fstate->state_index = 1;
196                                         goto state_in_end;
197                               }
198                               if (obufindex >= obuflen) {
199                                         result = FR_BUFFEROVERRUN;
200                                         fsmstate = FSTATE_END_OF_FRAME;
201                                         goto complete;
202                               }
203                               fstate->buffer[obufindex++] = chr;
204                               break;
205 
206                     state_in_end:
207                               /* FALLTHROUGH */
208 
209                     case FSTATE_IN_END:
210                               if (--fstate->state_index == 0) {
211                                         uint32_t crc;
212                                         const size_t fcslen = 2;
213 
214                                         fsmstate = FSTATE_END_OF_FRAME;
215 
216                                         if (obufindex < fcslen) {
217                                                   result = FR_FRAMEMALFORMED;
218                                                   goto complete;
219                                         }
220 
221                                         crc = crc_ccitt_16(INITFCS, fstate->buffer,
222                                             obufindex);
223 
224                                         /* Remove check bytes from buffer length */
225                                         obufindex -= fcslen;
226 
227                                         if (crc == GOODFCS)
228                                                   result = FR_FRAMEOK;
229                                         else
230                                                   result = FR_FRAMEBADFCS;
231 
232                                         goto complete;
233                               }
234                               break;
235 
236                     case FSTATE_END_OF_FRAME:
237                               if (chr != SIR_BOF)
238                                         break;
239 
240                               fsmstate = FSTATE_START_OF_FRAME;
241                               fstate->state_index = 1;
242                               /* FALLTHROUGH */
243                     case FSTATE_START_OF_FRAME:
244                               if (--fstate->state_index == 0) {
245                                         fsmstate = FSTATE_IN_DATA;
246                                         obufindex = 0;
247                               }
248                               break;
249                     }
250           }
251 
252           result = (fsmstate == FSTATE_END_OF_FRAME) ? FR_IDLE : FR_INPROGRESS;
253 
254  complete:
255           fstate->bufindex = obufindex;
256           fstate->fsmstate = fsmstate;
257           *blen = ibuflen;
258 
259           return result;
260 }
261 
262 uint32_t
crc_ccitt_16(uint32_t crcinit,uint8_t const * buf,size_t blen)263 crc_ccitt_16(uint32_t crcinit, uint8_t const *buf, size_t blen)
264 {
265 
266           while (blen-- > 0) {
267                     uint8_t chr;
268                     chr = *buf++;
269                     crcinit = updateFCS(crcinit, chr);
270           }
271           return crcinit;
272 }
273