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526e7c1d P |
1 | /* IPv6 helper functions */ |
2 | ||
3 | #include <stdlib.h> | |
4 | #include <string.h> | |
5 | #include <assert.h> | |
edd0553f | 6 | #include <arpa/inet.h> |
526e7c1d P |
7 | #include <netdb.h> |
8 | #include "irc_ipv6.h" | |
830f4525 | 9 | #include <stdio.h> |
526e7c1d | 10 | |
b98ba21f | 11 | #warning This source file is probably GPLed, it needs relicensing. |
df3bf970 | 12 | |
526e7c1d P |
13 | /** Convert an IP address to printable ASCII form. |
14 | * This is generally deprecated in favor of ircd_ntoa_r(). | |
15 | * @param[in] in Address to convert. | |
16 | * @return Pointer to a static buffer containing the readable form. | |
17 | */ | |
18 | const char* ircd_ntoa(const struct irc_in_addr* in) | |
19 | { | |
20 | static char buf[SOCKIPLEN]; | |
21 | return ircd_ntoa_r(buf, in); | |
22 | } | |
23 | ||
24 | /** Convert an IP address to printable ASCII form. | |
25 | * @param[out] buf Output buffer to write to. | |
26 | * @param[in] in Address to format. | |
27 | * @return Pointer to the output buffer \a buf. | |
28 | */ | |
29 | const char* ircd_ntoa_r(char* buf, const struct irc_in_addr* in) | |
30 | { | |
31 | assert(buf != NULL); | |
32 | assert(in != NULL); | |
33 | ||
34 | if (irc_in_addr_is_ipv4(in)) { | |
526e7c1d P |
35 | unsigned char *pch; |
36 | ||
37 | pch = (unsigned char*)&in->in6_16[6]; | |
830f4525 | 38 | sprintf(buf,"%d.%d.%d.%d",pch[0],pch[1],pch[2],pch[3]); |
526e7c1d P |
39 | return buf; |
40 | } else { | |
526e7c1d P |
41 | unsigned int pos, part, max_start, max_zeros, curr_zeros, ii; |
42 | ||
43 | /* Find longest run of zeros. */ | |
44 | for (max_start = ii = 1, max_zeros = curr_zeros = 0; ii < 8; ++ii) { | |
45 | if (!in->in6_16[ii]) | |
46 | curr_zeros++; | |
47 | else if (curr_zeros > max_zeros) { | |
48 | max_start = ii - curr_zeros; | |
49 | max_zeros = curr_zeros; | |
50 | curr_zeros = 0; | |
51 | } | |
52 | } | |
53 | if (curr_zeros > max_zeros) { | |
54 | max_start = ii - curr_zeros; | |
55 | max_zeros = curr_zeros; | |
56 | } | |
57 | ||
58 | /* Print out address. */ | |
59 | /** Append \a CH to the output buffer. */ | |
60 | #define APPEND(CH) do { buf[pos++] = (CH); } while (0) | |
61 | for (pos = ii = 0; (ii < 8); ++ii) { | |
62 | if ((max_zeros > 0) && (ii == max_start)) { | |
63 | APPEND(':'); | |
64 | ii += max_zeros - 1; | |
65 | continue; | |
66 | } | |
67 | part = ntohs(in->in6_16[ii]); | |
830f4525 | 68 | pos+=sprintf(buf+pos,"%x",part); |
526e7c1d P |
69 | if (ii < 7) |
70 | APPEND(':'); | |
71 | } | |
72 | #undef APPEND | |
73 | ||
74 | /* Nul terminate and return number of characters used. */ | |
75 | buf[pos++] = '\0'; | |
76 | return buf; | |
77 | } | |
78 | } | |
79 | ||
80 | /** Attempt to parse an IPv4 address into a network-endian form. | |
81 | * @param[in] input Input string. | |
82 | * @param[out] output Network-endian representation of the address. | |
83 | * @param[out] pbits Number of bits found in pbits. | |
84 | * @return Number of characters used from \a input, or 0 if the parse failed. | |
85 | */ | |
86 | static unsigned int | |
87 | ircd_aton_ip4(const char *input, unsigned int *output, unsigned char *pbits) | |
88 | { | |
89 | unsigned int dots = 0, pos = 0, part = 0, ip = 0, bits; | |
90 | ||
91 | /* Intentionally no support for bizarre IPv4 formats (plain | |
92 | * integers, octal or hex components) -- only vanilla dotted | |
93 | * decimal quads. | |
94 | */ | |
95 | if (input[0] == '.') | |
96 | return 0; | |
97 | bits = 32; | |
98 | while (1) switch (input[pos]) { | |
99 | case '\0': | |
100 | if (dots < 3) | |
101 | return 0; | |
102 | out: | |
103 | ip |= part << (24 - 8 * dots); | |
104 | *output = htonl(ip); | |
105 | if (pbits) | |
106 | *pbits = bits; | |
107 | return pos; | |
108 | case '.': | |
109 | if (input[++pos] == '.') | |
110 | return 0; | |
111 | ip |= part << (24 - 8 * dots++); | |
112 | part = 0; | |
113 | if (input[pos] == '*') { | |
114 | while (input[++pos] == '*') ; | |
115 | if (input[pos] != '\0') | |
116 | return 0; | |
117 | if (pbits) | |
118 | *pbits = dots * 8; | |
119 | *output = htonl(ip); | |
120 | return pos; | |
121 | } | |
122 | break; | |
123 | case '/': | |
124 | if (!pbits || !IsDigit(input[pos + 1])) | |
125 | return 0; | |
126 | for (bits = 0; IsDigit(input[++pos]); ) | |
127 | bits = bits * 10 + input[pos] - '0'; | |
128 | if (bits > 32) | |
129 | return 0; | |
130 | goto out; | |
131 | case '0': case '1': case '2': case '3': case '4': | |
132 | case '5': case '6': case '7': case '8': case '9': | |
133 | part = part * 10 + input[pos++] - '0'; | |
134 | if (part > 255) | |
135 | return 0; | |
136 | break; | |
137 | default: | |
138 | return 0; | |
139 | } | |
140 | } | |
141 | ||
142 | /** Parse a numeric IPv4 or IPv6 address into an irc_in_addr. | |
143 | * @param[in] input Input buffer. | |
144 | * @param[out] ip Receives parsed IP address. | |
145 | * @param[out] pbits If non-NULL, receives number of bits specified in address mask. | |
146 | * @return Number of characters used from \a input, or 0 if the | |
147 | * address was unparseable or malformed. | |
148 | */ | |
149 | int | |
150 | ipmask_parse(const char *input, struct irc_in_addr *ip, unsigned char *pbits) | |
151 | { | |
152 | char *colon; | |
153 | char *dot; | |
154 | ||
155 | assert(ip); | |
156 | assert(input); | |
157 | memset(ip, 0, sizeof(*ip)); | |
158 | colon = strchr(input, ':'); | |
159 | dot = strchr(input, '.'); | |
160 | ||
161 | if (colon && (!dot || (dot > colon))) { | |
162 | unsigned int part = 0, pos = 0, ii = 0, colon = 8; | |
163 | const char *part_start = NULL; | |
164 | ||
165 | /* Parse IPv6, possibly like ::127.0.0.1. | |
166 | * This is pretty straightforward; the only trick is borrowed | |
167 | * from Paul Vixie (BIND): when it sees a "::" continue as if | |
168 | * it were a single ":", but note where it happened, and fill | |
169 | * with zeros afterward. | |
170 | */ | |
171 | if (input[pos] == ':') { | |
172 | if ((input[pos+1] != ':') || (input[pos+2] == ':')) | |
173 | return 0; | |
174 | colon = 0; | |
175 | pos += 2; | |
176 | part_start = input + pos; | |
177 | } | |
178 | while (ii < 8) switch (input[pos]) { | |
179 | unsigned char chval; | |
180 | case '0': case '1': case '2': case '3': case '4': | |
181 | case '5': case '6': case '7': case '8': case '9': | |
182 | chval = input[pos] - '0'; | |
183 | use_chval: | |
184 | part = (part << 4) | chval; | |
185 | if (part > 0xffff) | |
186 | return 0; | |
187 | pos++; | |
188 | break; | |
189 | case 'A': case 'B': case 'C': case 'D': case 'E': case 'F': | |
190 | chval = input[pos] - 'A' + 10; | |
191 | goto use_chval; | |
192 | case 'a': case 'b': case 'c': case 'd': case 'e': case 'f': | |
193 | chval = input[pos] - 'a' + 10; | |
194 | goto use_chval; | |
195 | case ':': | |
196 | part_start = input + ++pos; | |
197 | if (input[pos] == '.') | |
198 | return 0; | |
199 | ip->in6_16[ii++] = htons(part); | |
200 | part = 0; | |
201 | if (input[pos] == ':') { | |
202 | if (colon < 8) | |
203 | return 0; | |
204 | colon = ii; | |
205 | pos++; | |
206 | } | |
207 | break; | |
208 | case '.': { | |
209 | uint32_t ip4; | |
210 | unsigned int len; | |
211 | len = ircd_aton_ip4(part_start, &ip4, pbits); | |
212 | if (!len || (ii > 6)) | |
213 | return 0; | |
214 | ip->in6_16[ii++] = htons(ntohl(ip4) >> 16); | |
215 | ip->in6_16[ii++] = htons(ntohl(ip4) & 65535); | |
216 | if (pbits) | |
217 | *pbits += 96; | |
218 | pos = part_start + len - input; | |
219 | goto finish; | |
220 | } | |
221 | case '/': | |
222 | if (!pbits || !IsDigit(input[pos + 1])) | |
223 | return 0; | |
224 | ip->in6_16[ii++] = htons(part); | |
225 | for (part = 0; IsDigit(input[++pos]); ) | |
226 | part = part * 10 + input[pos] - '0'; | |
227 | if (part > 128) | |
228 | return 0; | |
229 | *pbits = part; | |
230 | goto finish; | |
231 | case '*': | |
232 | while (input[++pos] == '*') ; | |
233 | if (input[pos] != '\0' || colon < 8) | |
234 | return 0; | |
235 | if (pbits) | |
236 | *pbits = ii * 16; | |
237 | return pos; | |
238 | case '\0': | |
239 | ip->in6_16[ii++] = htons(part); | |
240 | if (colon == 8 && ii < 8) | |
241 | return 0; | |
242 | if (pbits) | |
243 | *pbits = 128; | |
244 | goto finish; | |
245 | default: | |
246 | return 0; | |
247 | } | |
248 | finish: | |
249 | if (colon < 8) { | |
250 | unsigned int jj; | |
251 | /* Shift stuff after "::" up and fill middle with zeros. */ | |
252 | for (jj = 0; jj < ii - colon; jj++) | |
253 | ip->in6_16[7 - jj] = ip->in6_16[ii - jj - 1]; | |
254 | for (jj = 0; jj < 8 - ii; jj++) | |
255 | ip->in6_16[colon + jj] = 0; | |
256 | } | |
257 | return pos; | |
258 | } else if (dot || strchr(input, '/')) { | |
259 | unsigned int addr; | |
260 | int len = ircd_aton_ip4(input, &addr, pbits); | |
261 | if (len) { | |
262 | ip->in6_16[5] = htons(65535); | |
263 | ip->in6_16[6] = htons(ntohl(addr) >> 16); | |
264 | ip->in6_16[7] = htons(ntohl(addr) & 65535); | |
265 | if (pbits) | |
266 | *pbits += 96; | |
267 | } | |
268 | return len; | |
269 | } else if (input[0] == '*') { | |
270 | unsigned int pos = 0; | |
271 | while (input[++pos] == '*') ; | |
272 | if (input[pos] != '\0') | |
273 | return 0; | |
274 | if (pbits) | |
275 | *pbits = 0; | |
276 | return pos; | |
277 | } else return 0; /* parse failed */ | |
278 | } | |
279 | ||
280 | /* from numnicks.c */ | |
281 | ||
282 | /** | |
283 | * Converts a numeric to the corresponding character. | |
284 | * The following characters are currently known to be forbidden: | |
285 | * | |
286 | * '\\0' : Because we use '\\0' as end of line. | |
287 | * | |
288 | * ' ' : Because parse_*() uses this as parameter separator. | |
289 | * | |
290 | * ':' : Because parse_server() uses this to detect if a prefix is a | |
291 | * numeric or a name. | |
292 | * | |
293 | * '+' : Because m_nick() uses this to determine if parv[6] is a | |
294 | * umode or not. | |
295 | * | |
296 | * '&', '#', '$', '@' and '%' : | |
297 | * Because m_message() matches these characters to detect special cases. | |
298 | */ | |
299 | static const char convert2y[] = { | |
300 | 'A','B','C','D','E','F','G','H','I','J','K','L','M','N','O','P', | |
301 | 'Q','R','S','T','U','V','W','X','Y','Z','a','b','c','d','e','f', | |
302 | 'g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v', | |
303 | 'w','x','y','z','0','1','2','3','4','5','6','7','8','9','[',']' | |
304 | }; | |
305 | ||
306 | /** Converts a character to its (base64) numnick value. */ | |
307 | static const unsigned int convert2n[] = { | |
308 | 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, | |
309 | 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, | |
310 | 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, | |
311 | 52,53,54,55,56,57,58,59,60,61, 0, 0, 0, 0, 0, 0, | |
312 | 0, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9,10,11,12,13,14, | |
313 | 15,16,17,18,19,20,21,22,23,24,25,62, 0,63, 0, 0, | |
314 | 0,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40, | |
315 | 41,42,43,44,45,46,47,48,49,50,51, 0, 0, 0, 0, 0, | |
316 | ||
317 | 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, | |
318 | 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, | |
319 | 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, | |
320 | 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, | |
321 | 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, | |
322 | 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, | |
323 | 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, | |
324 | 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 | |
325 | }; | |
326 | ||
327 | /** Number of bits encoded in one numnick character. */ | |
328 | #define NUMNICKLOG 6 | |
329 | /** Bitmask to select value of next numnick character. */ | |
330 | #define NUMNICKMASK 63 /* (NUMNICKBASE-1) */ | |
331 | /** Number of servers representable in a numnick. */ | |
332 | ||
333 | /* *INDENT-ON* */ | |
334 | ||
335 | /** Convert a string to its value as a numnick. | |
336 | * @param[in] s Numnick string to decode. | |
337 | * @return %Numeric nickname value. | |
338 | */ | |
339 | unsigned int base64toint(const char* s) | |
340 | { | |
341 | unsigned int i = convert2n[(unsigned char) *s++]; | |
342 | while (*s) { | |
343 | i <<= NUMNICKLOG; | |
344 | i += convert2n[(unsigned char) *s++]; | |
345 | } | |
346 | return i; | |
347 | } | |
348 | ||
349 | /** Encode a number as a numnick. | |
350 | * @param[out] buf Output buffer. | |
351 | * @param[in] v Value to encode. | |
352 | * @param[in] count Number of numnick digits to write to \a buf. | |
353 | */ | |
354 | const char* inttobase64(char* buf, unsigned int v, unsigned int count) | |
355 | { | |
356 | buf[count] = '\0'; | |
357 | while (count > 0) { | |
358 | buf[--count] = convert2y[(v & NUMNICKMASK)]; | |
359 | v >>= NUMNICKLOG; | |
360 | } | |
361 | return buf; | |
362 | } | |
363 | ||
364 | /** Number of bits encoded in one numnick character. */ | |
365 | #define NUMNICKLOG 6 | |
366 | ||
367 | /** Encode an IP address in the base64 used by numnicks. | |
368 | * For IPv4 addresses (including IPv4-mapped and IPv4-compatible IPv6 | |
369 | * addresses), the 32-bit host address is encoded directly as six | |
370 | * characters. | |
371 | * | |
372 | * For IPv6 addresses, each 16-bit address segment is encoded as three | |
373 | * characters, but the longest run of zero segments is encoded using an | |
374 | * underscore. | |
375 | * @param[out] buf Output buffer to write to. | |
376 | * @param[in] addr IP address to encode. | |
377 | * @param[in] count Number of bytes writable to \a buf. | |
378 | * @param[in] v6_ok If non-zero, peer understands base-64 encoded IPv6 addresses. | |
379 | */ | |
380 | const char* iptobase64(char* buf, const struct irc_in_addr* addr, unsigned int count, int v6_ok) | |
381 | { | |
382 | if (irc_in_addr_is_ipv4(addr)) { | |
383 | assert(count >= 6); | |
384 | inttobase64(buf, (ntohs(addr->in6_16[6]) << 16) | ntohs(addr->in6_16[7]), 6); | |
385 | } else if (!v6_ok) { | |
386 | assert(count >= 6); | |
387 | if (addr->in6_16[0] == htons(0x2002)) | |
388 | inttobase64(buf, (ntohs(addr->in6_16[1]) << 16) | ntohs(addr->in6_16[2]), 6); | |
389 | else | |
390 | strcpy(buf, "AAAAAA"); | |
391 | } else { | |
392 | unsigned int max_start, max_zeros, curr_zeros, zero, ii; | |
393 | char *output = buf; | |
394 | ||
395 | assert(count >= 25); | |
396 | /* Can start by printing out the leading non-zero parts. */ | |
397 | for (ii = 0; (addr->in6_16[ii]) && (ii < 8); ++ii) { | |
398 | inttobase64(output, ntohs(addr->in6_16[ii]), 3); | |
399 | output += 3; | |
400 | } | |
401 | /* Find the longest run of zeros. */ | |
402 | for (max_start = zero = ii, max_zeros = curr_zeros = 0; ii < 8; ++ii) { | |
403 | if (!addr->in6_16[ii]) | |
404 | curr_zeros++; | |
405 | else if (curr_zeros > max_zeros) { | |
406 | max_start = ii - curr_zeros; | |
407 | max_zeros = curr_zeros; | |
408 | curr_zeros = 0; | |
409 | } | |
410 | } | |
411 | if (curr_zeros > max_zeros) { | |
412 | max_start = ii - curr_zeros; | |
413 | max_zeros = curr_zeros; | |
414 | curr_zeros = 0; | |
415 | } | |
416 | /* Print the rest of the address */ | |
417 | for (ii = zero; ii < 8; ) { | |
418 | if ((ii == max_start) && max_zeros) { | |
419 | *output++ = '_'; | |
420 | ii += max_zeros; | |
421 | } else { | |
422 | inttobase64(output, ntohs(addr->in6_16[ii]), 3); | |
423 | output += 3; | |
424 | ii++; | |
425 | } | |
426 | } | |
427 | *output = '\0'; | |
428 | } | |
429 | return buf; | |
430 | } | |
431 | ||
432 | /** Decode an IP address from base64. | |
433 | * @param[in] input Input buffer to decode. | |
434 | * @param[out] addr IP address structure to populate. | |
435 | */ | |
436 | void base64toip(const char* input, struct irc_in_addr* addr) | |
437 | { | |
438 | memset(addr, 0, sizeof(*addr)); | |
439 | if (strlen(input) == 6) { | |
440 | unsigned int in = base64toint(input); | |
441 | /* An all-zero address should stay that way. */ | |
442 | if (in) { | |
443 | addr->in6_16[5] = htons(65535); | |
444 | addr->in6_16[6] = htons(in >> 16); | |
445 | addr->in6_16[7] = htons(in & 65535); | |
446 | } | |
447 | } else { | |
448 | unsigned int pos = 0; | |
449 | do { | |
450 | if (*input == '_') { | |
451 | unsigned int left; | |
452 | for (left = (25 - strlen(input)) / 3 - pos; left; left--) | |
453 | addr->in6_16[pos++] = 0; | |
454 | input++; | |
455 | } else { | |
456 | unsigned short accum = convert2n[(unsigned char)*input++]; | |
457 | accum = (accum << NUMNICKLOG) | convert2n[(unsigned char)*input++]; | |
458 | accum = (accum << NUMNICKLOG) | convert2n[(unsigned char)*input++]; | |
459 | addr->in6_16[pos++] = ntohs(accum); | |
460 | } | |
461 | } while (pos < 8); | |
462 | } | |
463 | } | |
464 |