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ws.c (11719B)
1 #include "ws.h"
2 #include "libsheepyObject.h"
3 // from libsheepy.h:
4 // internal
5 // u8, u16, u32, u64
6 // randomUrandomOpen, randomWord, randomUrandomClose
7 // bCatS, eqS
8 // logE
9 // range
10 // MIN, MIN3
11 //
12 // from libsheepyObject.h:
13 // findG, indexOfG
14 // setG
15
16 #include <arpa/inet.h>
17
18 /* enable/disable logging */
19 #undef pLog
20 #define pLog(...)
21
22 #define BASE64_ENCODED_SIZE(len) (len+2)/3*4+1
23
24 const char *BASE64_CHARS = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
25
26 void _base64_encode_triple(u8 triple[3], char result[4]) {
27 u32 tripleValue;
28
29 tripleValue = triple[0];
30 tripleValue *= 256;
31 tripleValue += triple[1];
32 tripleValue *= 256;
33 tripleValue += triple[2];
34
35 range(i,4) {
36 result[3-i] = BASE64_CHARS[tripleValue%64];
37 tripleValue /= 64;
38 }
39 }
40
41 bool base64_encode(u8 *source, size_t sourcelen, char *target, size_t targetlen) {
42
43 if ((sourcelen+2)/3*4 > targetlen-1)
44 return false;
45
46 while (sourcelen >= 3) {
47 _base64_encode_triple(source, target);
48 sourcelen -= 3;
49 source += 3;
50 target += 4;
51 }
52
53 if (sourcelen > 0) {
54 u8 temp[3];
55 memset(temp, 0, sizeof(temp));
56 memcpy(temp, source, sourcelen);
57 _base64_encode_triple(temp, target);
58 target[3] = '=';
59 if (sourcelen == 1)
60 target[2] = '=';
61
62 target += 4;
63 }
64
65 target[0] = 0;
66
67 return true;
68 }
69
70 struct sha1 {
71 u64 len; /* processed message length */
72 u32 h[5]; /* hash state */
73 u8 buf[64]; /* message block buffer */
74 };
75
76 #define SHA1_DIGEST_LEN 20
77
78 /* reset state */
79 internal void sha1Init(struct sha1 *ctx);
80
81 /* process message */
82 internal void sha1Update(struct sha1 *ctx, const void *m, u64 len);
83
84 /* get message digest
85 * state is ruined after sum, keep a copy if multiple sum is needed
86 * part of the message might be left in s, zero it if secrecy is needed
87 */
88 internal void sha1Final(struct sha1 *ctx, u8 md[SHA1_DIGEST_LEN]);
89
90 internal u32 rol(u32 n, u8 k) { return (n << k) | (n >> (32-k)); }
91
92 #define F0(b,c,d) (d ^ (b & (c ^ d)))
93 #define F1(b,c,d) (b ^ c ^ d)
94 #define F2(b,c,d) ((b & c) | (d & (b | c)))
95 #define F3(b,c,d) (b ^ c ^ d)
96 #define G0(a,b,c,d,e,i) e += rol(a,5)+F0(b,c,d)+W[i]+0x5A827999; b = rol(b,30)
97 #define G1(a,b,c,d,e,i) e += rol(a,5)+F1(b,c,d)+W[i]+0x6ED9EBA1; b = rol(b,30)
98 #define G2(a,b,c,d,e,i) e += rol(a,5)+F2(b,c,d)+W[i]+0x8F1BBCDC; b = rol(b,30)
99 #define G3(a,b,c,d,e,i) e += rol(a,5)+F3(b,c,d)+W[i]+0xCA62C1D6; b = rol(b,30)
100
101 internal void processblock(struct sha1 *s, const u8 *buf) {
102 u32 W[80], a, b, c, d, e;
103 u8 i;
104
105 for (i = 0; i < 16; i++) {
106 W[i] = (u32)buf[4*i]<<24;
107 W[i] |= (u32)buf[4*i+1]<<16;
108 W[i] |= (u32)buf[4*i+2]<<8;
109 W[i] |= buf[4*i+3];
110 }
111 for (; i < 80; i++)
112 W[i] = rol(W[i-3] ^ W[i-8] ^ W[i-14] ^ W[i-16], 1);
113 a = s->h[0];
114 b = s->h[1];
115 c = s->h[2];
116 d = s->h[3];
117 e = s->h[4];
118 for (i = 0; i < 20; ) {
119 G0(a,b,c,d,e,i++);
120 G0(e,a,b,c,d,i++);
121 G0(d,e,a,b,c,i++);
122 G0(c,d,e,a,b,i++);
123 G0(b,c,d,e,a,i++);
124 }
125 while (i < 40) {
126 G1(a,b,c,d,e,i++);
127 G1(e,a,b,c,d,i++);
128 G1(d,e,a,b,c,i++);
129 G1(c,d,e,a,b,i++);
130 G1(b,c,d,e,a,i++);
131 }
132 while (i < 60) {
133 G2(a,b,c,d,e,i++);
134 G2(e,a,b,c,d,i++);
135 G2(d,e,a,b,c,i++);
136 G2(c,d,e,a,b,i++);
137 G2(b,c,d,e,a,i++);
138 }
139 while (i < 80) {
140 G3(a,b,c,d,e,i++);
141 G3(e,a,b,c,d,i++);
142 G3(d,e,a,b,c,i++);
143 G3(c,d,e,a,b,i++);
144 G3(b,c,d,e,a,i++);
145 }
146 s->h[0] += a;
147 s->h[1] += b;
148 s->h[2] += c;
149 s->h[3] += d;
150 s->h[4] += e;
151 }
152
153 internal void pad(struct sha1 *s) {
154 u8 r = s->len % 64;
155
156 s->buf[r++] = 0x80;
157 if (r > 56) {
158 memset(s->buf + r, 0, 64 - r);
159 r = 0;
160 processblock(s, s->buf);
161 }
162 memset(s->buf + r, 0, 56 - r);
163 s->len *= 8;
164 s->buf[56] = s->len >> 56;
165 s->buf[57] = s->len >> 48;
166 s->buf[58] = s->len >> 40;
167 s->buf[59] = s->len >> 32;
168 s->buf[60] = s->len >> 24;
169 s->buf[61] = s->len >> 16;
170 s->buf[62] = s->len >> 8;
171 s->buf[63] = s->len;
172 processblock(s, s->buf);
173 }
174
175 internal void sha1Init(struct sha1 *s) {
176 s->len = 0;
177 s->h[0] = 0x67452301;
178 s->h[1] = 0xEFCDAB89;
179 s->h[2] = 0x98BADCFE;
180 s->h[3] = 0x10325476;
181 s->h[4] = 0xC3D2E1F0;
182 }
183
184 internal void sha1Final(struct sha1 *s, u8 md[SHA1_DIGEST_LEN]) {
185
186 pad(s);
187 range(i,5) {
188 md[4*i] = s->h[i] >> 24;
189 md[4*i+1] = s->h[i] >> 16;
190 md[4*i+2] = s->h[i] >> 8;
191 md[4*i+3] = s->h[i];
192 }
193 }
194
195 internal void sha1Update(struct sha1 *s, const void *m, u64 len) {
196 const u8 *p = m;
197 u8 r = s->len % 64;
198
199 s->len += len;
200 if (r) {
201 if (len < 64 - r) {
202 memcpy(s->buf + r, p, len);
203 return;
204 }
205 memcpy(s->buf + r, p, 64 - r);
206 len -= 64 - r;
207 p += 64 - r;
208 processblock(s, s->buf);
209 }
210 for (; len >= 64; len -= 64, p += 64)
211 processblock(s, p);
212 memcpy(s->buf, p, len);
213 }
214
215 internal u64 keyRnd[2];
216 internal char clientKey[BASE64_ENCODED_SIZE(sizeof(keyRnd))];
217
218 internal const char handshake[] =
219 "GET /connect HTTP/1.1\r\n"
220 "Host: %s\r\n"
221 "Upgrade: websocket\r\n"
222 "Connection: Upgrade\r\n"
223 "Sec-WebSocket-Key: %s\r\n"
224 "Sec-WebSocket-Version: 13\r\n"
225 "\r\n";
226
227 internal const char serverResponse[] = "258EAFA5-E914-47DA-95CA-C5AB0DC85B11";
228
229 size_t wsHandshakeSize(char *hostname) {
230 return (sizeof(handshake) -1 -4) + BASE64_ENCODED_SIZE(sizeof(keyRnd))-1 + strlen(hostname) +1;
231 }
232
233 int wsHandshake(char *frame, size_t size, char *hostname) {
234
235 randomUrandomOpen();
236 keyRnd[0] = randomWord();
237 keyRnd[1] = randomWord();
238 randomUrandomClose();
239
240 base64_encode((u8*)keyRnd, sizeof(keyRnd), clientKey, sizeof(clientKey));
241
242 snprintf(frame, size, "GET /connect HTTP/1.1\r\n"
243 "Host: %s\r\n"
244 "Upgrade: websocket\r\n"
245 "Connection: Upgrade\r\n"
246 "Sec-WebSocket-Key: %s\r\n"
247 "Sec-WebSocket-Version: 13\r\n"
248 "\r\n", hostname, clientKey);
249 return 0;
250 }
251
252 bool wsHanskakeCheck(char *frame, size_t size) {
253 char *srvRes;
254
255 if (srvRes = findG(frame, "sec-websocket-accept: ")) {
256 srvRes += 22;
257 int idx = indexOfG(srvRes, "\r\n");
258
259 if ((srvRes - frame + idx) > size)
260 return false;
261
262 setG(srvRes, idx, 0);
263
264 // createAcceptKey
265 char s[128];
266 bCatS(s, clientKey, serverResponse);
267
268 struct sha1 shc;
269 sha1Init(&shc);
270 sha1Update(&shc, s, BASE64_ENCODED_SIZE(sizeof(keyRnd)) -1 + sizeof(serverResponse) -1);
271 u8 digest[SHA1_DIGEST_LEN];
272 sha1Final(&shc, digest);
273
274 char base64Digest[800];
275 base64_encode(digest, sizeof(digest), base64Digest, sizeof(base64Digest));
276 if (!eqS(srvRes, base64Digest)) {
277 logE("Bad server response!");
278 return false;
279 }
280 }
281 else {
282 return false;
283 }
284 return true;
285 }
286
287 #define WS_FINAL_FRAME 1 << 7
288 #define WS_OP_MASK 0xF
289 #define WS_MASK 1 << 7
290 #define WS_HEADER_SIZE 2
291 #define WS_MASK_SIZE 4
292 #define WS_LEN_MASK 0x7F
293
294 #define WS_PAYLOAD_EXTEND_1 126
295 #define WS_PAYLOAD_EXTEND_2 127
296
297 #define WS_LEN_SIZE_1 2
298 #define WS_LEN_SIZE_2 8
299
300 // 1 if opcode is control frame opcode, otherwise 0
301 #define isCtlFrame(opcode) ((opcode >> 3) & 1)
302
303 ssize_t wsMaskSize(wsOpt op, size_t pSize) {
304 if (isCtlFrame(op) && pSize >= WS_PAYLOAD_EXTEND_1) return -1;
305 if (pSize < WS_PAYLOAD_EXTEND_1) return pSize + WS_HEADER_SIZE + WS_MASK_SIZE;
306 if (pSize < 1 << 16) return pSize + WS_HEADER_SIZE + WS_MASK_SIZE + WS_LEN_SIZE_1;
307 return pSize + WS_HEADER_SIZE + WS_MASK_SIZE + WS_LEN_SIZE_2;
308 }
309
310 ssize_t wsNoMaskSize(wsOpt op, size_t pSize) {
311 if (isCtlFrame(op) && pSize >= WS_PAYLOAD_EXTEND_1) return -1;
312 if (pSize < WS_PAYLOAD_EXTEND_1) return pSize + WS_HEADER_SIZE;
313 if (pSize < 1 << 16) return pSize + WS_HEADER_SIZE + WS_LEN_SIZE_1;
314 return pSize + WS_HEADER_SIZE + WS_LEN_SIZE_2;
315 }
316
317 ssize_t wsControlMaskSize(void) {
318 return WS_HEADER_SIZE + WS_MASK_SIZE;
319 }
320
321 ssize_t wsControlNoMaskSize(void) {
322 return WS_HEADER_SIZE;
323 }
324
325 bool wsMask(char *frame, size_t size, wsOpt op, char *payload, size_t pSize, bool final) {
326 #define WS_STEP1\
327 ssize_t frameSize = wsMaskSize(op, pSize);\
328 \
329 if (frameSize == -1 || frameSize > size) return false;\
330 \
331 zeroBuf(frame, frameSize);\
332 \
333 if (final) frame[0] = WS_FINAL_FRAME | op;\
334 else frame[0] = op;
335 WS_STEP1;
336
337 u8 wsPLen, maskOffset;
338 if (pSize < WS_PAYLOAD_EXTEND_1) {
339 wsPLen = pSize;
340 maskOffset = WS_HEADER_SIZE;
341 }
342 else if (pSize < 1 << 16) {
343 wsPLen = WS_PAYLOAD_EXTEND_1;
344 maskOffset = WS_HEADER_SIZE + WS_LEN_SIZE_1;
345 u16 *len = (u16*)&frame[2];
346 *len = htons((u16)pSize);
347 }
348 else {
349 wsPLen = WS_PAYLOAD_EXTEND_2;
350 maskOffset = WS_HEADER_SIZE + WS_LEN_SIZE_2;
351 u64 *len = (u64*)&frame[2];
352 *len = htobe64(pSize);
353
354 }
355 frame[1] = WS_MASK | wsPLen;
356 // mask key 4 bytes, random = always 0
357
358 u8 payloadOffset = maskOffset + WS_MASK_SIZE;
359
360 strncpy(frame+payloadOffset, payload, pSize);
361
362 range(i, pSize) {
363 frame[i + payloadOffset] ^= frame[maskOffset + (i % 4)];
364 }
365
366 return true;
367 }
368
369 bool wsNoMask(char *frame, size_t size, wsOpt op, char *payload, size_t pSize, bool final) {
370 WS_STEP1;
371
372 u8 wsPLen, payloadOffset;
373 if (pSize < WS_PAYLOAD_EXTEND_1) {
374 wsPLen = pSize;
375 payloadOffset = WS_HEADER_SIZE;
376 }
377 else if (pSize < 1 << 16) {
378 wsPLen = WS_PAYLOAD_EXTEND_1;
379 payloadOffset = WS_HEADER_SIZE + WS_LEN_SIZE_1;
380 u16 *len = (u16*)&frame[2];
381 *len = htons((u16)pSize);
382 }
383 else {
384 wsPLen = WS_PAYLOAD_EXTEND_2;
385 payloadOffset = WS_HEADER_SIZE + WS_LEN_SIZE_2;
386 u64 *len = (u64*)&frame[2];
387 *len = htobe64(pSize);
388
389 }
390 frame[1] = wsPLen;
391
392 strncpy(frame+payloadOffset, payload, pSize);
393
394 return true;
395 }
396
397 #define genControlFrame(SIZE_FUNC) \
398 ssize_t frameSize = SIZE_FUNC(op, 0);\
399 zeroBuf(frame, frameSize);\
400 frame[0] = WS_FINAL_FRAME | op
401
402 bool wsControlMask(char *frame, wsOpt op) {
403
404 if (!isCtlFrame(op)) return false;
405 genControlFrame(wsMaskSize);
406 frame[1] = WS_MASK;
407
408 return true;
409 }
410
411 bool wsControlNoMask(char *frame, wsOpt op) {
412
413 if (!isCtlFrame(op)) return false;
414 genControlFrame(wsNoMaskSize);
415
416 return true;
417 }
418
419
420 size_t wsDecodeSize(char *frame) {
421 u8 len = frame[1] & WS_LEN_MASK;
422 switch(len) {
423 case WS_PAYLOAD_EXTEND_1:;
424 u16 len1 = *(u16*)&frame[2];
425 return ntohs(len1);
426 case WS_PAYLOAD_EXTEND_2:;
427 u64 len2 = *(u64*)&frame[2];
428 return be64toh(len2);
429 default:
430 return len;
431 }
432 }
433
434 void wsDecode(char *data, size_t size, char *frame, size_t fSize) {
435
436 size_t sz = MIN3(wsDecodeSize(frame), size, fSize);
437 char *payload = wsDecodePayOffset(frame);
438 strncpy(data, payload, sz);
439
440 if (wsIsMasked(frame)) {
441 char *mask = payload -4;
442 range(i, sz) {
443 data[i] ^= *(mask + (i % 4));
444 }
445 }
446 }
447
448 char *wsDecodePayOffset(char *frame) {
449 char *r;
450 r = frame + WS_HEADER_SIZE;
451 u8 len = frame[1] & WS_LEN_MASK;
452 if (len == WS_PAYLOAD_EXTEND_1) {
453 r += WS_LEN_SIZE_1;
454 }
455 else if (len == WS_PAYLOAD_EXTEND_2) {
456 r += WS_LEN_SIZE_2;
457 }
458 if (wsIsMasked(frame)) r += WS_MASK_SIZE;
459 return r;
460 }
461
462 char *wsDecodeInPlace(char *frame, size_t size) {
463
464 char *r = wsDecodePayOffset(frame);
465 if (wsIsMasked(frame)) {
466 char *mask = r -4;
467 size_t sz = MIN(wsDecodeSize(frame), size);
468 range(i, sz) {
469 *(r+i) ^= *(mask + (i % 4));
470 }
471 }
472 return r;
473 }
474
475 bool wsIsFinal(char *frame) {
476 return (frame[0] & WS_FINAL_FRAME) == WS_FINAL_FRAME;
477 }
478
479 bool wsIsMasked(char *frame) {
480 return (frame[1] & WS_MASK) == WS_MASK;
481 }
482
483 wsOpt wsDecodeOp(char *frame) {
484 return (wsOpt) frame[0] & WS_OP_MASK;
485 }
486
487 bool checkLibsheepyVersionWs(const char *currentLibsheepyVersion) {
488 return eqG(currentLibsheepyVersion, LIBSHEEPY_VERSION);
489 }
490