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1 // Copyright 2009, Google Inc.
2 // All rights reserved.
3 //
4 // Redistribution and use in source and binary forms, with or without
5 // modification, are permitted provided that the following conditions are
6 // met:
7 //
8 //     * Redistributions of source code must retain the above copyright
9 // notice, this list of conditions and the following disclaimer.
10 //     * Redistributions in binary form must reproduce the above
11 // copyright notice, this list of conditions and the following disclaimer
12 // in the documentation and/or other materials provided with the
13 // distribution.
14 //     * Neither the name of Google Inc. nor the names of its
15 // contributors may be used to endorse or promote products derived from
16 // this software without specific prior written permission.
17 //
18 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
19 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
20 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
21 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
22 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
23 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
24 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
25 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
26 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
27 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
28 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29 
30 #include "googleurl/src/url_canon_ip.h"
31 
32 #include <stdlib.h>
33 
34 #include "base/basictypes.h"
35 #include "base/logging.h"
36 #include "googleurl/src/url_canon_internal.h"
37 
38 namespace url_canon {
39 
40 namespace {
41 
42 // Converts one of the character types that represent a numerical base to the
43 // corresponding base.
BaseForType(SharedCharTypes type)44 int BaseForType(SharedCharTypes type) {
45   switch (type) {
46     case CHAR_HEX:
47       return 16;
48     case CHAR_DEC:
49       return 10;
50     case CHAR_OCT:
51       return 8;
52     default:
53       return 0;
54   }
55 }
56 
57 template<typename CHAR, typename UCHAR>
DoFindIPv4Components(const CHAR * spec,const url_parse::Component & host,url_parse::Component components[4])58 bool DoFindIPv4Components(const CHAR* spec,
59                           const url_parse::Component& host,
60                           url_parse::Component components[4]) {
61   if (!host.is_nonempty())
62     return false;
63 
64   int cur_component = 0;  // Index of the component we're working on.
65   int cur_component_begin = host.begin;  // Start of the current component.
66   int end = host.end();
67   for (int i = host.begin; /* nothing */; i++) {
68     if (i >= end || spec[i] == '.') {
69       // Found the end of the current component.
70       int component_len = i - cur_component_begin;
71       components[cur_component] =
72           url_parse::Component(cur_component_begin, component_len);
73 
74       // The next component starts after the dot.
75       cur_component_begin = i + 1;
76       cur_component++;
77 
78       // Don't allow empty components (two dots in a row), except we may
79       // allow an empty component at the end (this would indicate that the
80       // input ends in a dot). We also want to error if the component is
81       // empty and it's the only component (cur_component == 1).
82       if (component_len == 0 && (i < end || cur_component == 1))
83         return false;
84 
85       if (i >= end)
86         break;  // End of the input.
87 
88       if (cur_component == 4) {
89         // Anything else after the 4th component is an error unless it is a
90         // dot that would otherwise be treated as the end of input.
91         if (spec[i] == '.' && i + 1 == end)
92           break;
93         return false;
94       }
95     } else if (static_cast<UCHAR>(spec[i]) >= 0x80 ||
96                !IsIPv4Char(static_cast<unsigned char>(spec[i]))) {
97       // Invalid character for an IPv4 address.
98       return false;
99     }
100   }
101 
102   // Fill in any unused components.
103   while (cur_component < 4)
104     components[cur_component++] = url_parse::Component();
105   return true;
106 }
107 
108 // Converts an IPv4 component to a 32-bit number, while checking for overflow.
109 //
110 // Possible return values:
111 // - IPV4    - The number was valid, and did not overflow.
112 // - BROKEN  - The input was numeric, but too large for a 32-bit field.
113 // - NEUTRAL - Input was not numeric.
114 //
115 // The input is assumed to be ASCII. FindIPv4Components should have stripped
116 // out any input that is greater than 7 bits. The components are assumed
117 // to be non-empty.
118 template<typename CHAR>
IPv4ComponentToNumber(const CHAR * spec,const url_parse::Component & component,uint32 * number)119 CanonHostInfo::Family IPv4ComponentToNumber(
120     const CHAR* spec,
121     const url_parse::Component& component,
122     uint32* number) {
123   // Figure out the base
124   SharedCharTypes base;
125   int base_prefix_len = 0;  // Size of the prefix for this base.
126   if (spec[component.begin] == '0') {
127     // Either hex or dec, or a standalone zero.
128     if (component.len == 1) {
129       base = CHAR_DEC;
130     } else if (spec[component.begin + 1] == 'X' ||
131                spec[component.begin + 1] == 'x') {
132       base = CHAR_HEX;
133       base_prefix_len = 2;
134     } else {
135       base = CHAR_OCT;
136       base_prefix_len = 1;
137     }
138   } else {
139     base = CHAR_DEC;
140   }
141 
142   // Extend the prefix to consume all leading zeros.
143   while (base_prefix_len < component.len &&
144          spec[component.begin + base_prefix_len] == '0')
145     base_prefix_len++;
146 
147   // Put the component, minus any base prefix, into a NULL-terminated buffer so
148   // we can call the standard library.  Because leading zeros have already been
149   // discarded, filling the entire buffer is guaranteed to trigger the 32-bit
150   // overflow check.
151   const int kMaxComponentLen = 16;
152   char buf[kMaxComponentLen + 1];  // digits + '\0'
153   int dest_i = 0;
154   for (int i = component.begin + base_prefix_len; i < component.end(); i++) {
155     // We know the input is 7-bit, so convert to narrow (if this is the wide
156     // version of the template) by casting.
157     char input = static_cast<char>(spec[i]);
158 
159     // Validate that this character is OK for the given base.
160     if (!IsCharOfType(input, base))
161       return CanonHostInfo::NEUTRAL;
162 
163     // Fill the buffer, if there's space remaining.  This check allows us to
164     // verify that all characters are numeric, even those that don't fit.
165     if (dest_i < kMaxComponentLen)
166       buf[dest_i++] = input;
167   }
168 
169   buf[dest_i] = '\0';
170 
171   // Use the 64-bit strtoi so we get a big number (no hex, decimal, or octal
172   // number can overflow a 64-bit number in <= 16 characters).
173   uint64 num = _strtoui64(buf, NULL, BaseForType(base));
174 
175   // Check for 32-bit overflow.
176   if (num > kuint32max)
177     return CanonHostInfo::BROKEN;
178 
179   // No overflow.  Success!
180   *number = static_cast<uint32>(num);
181   return CanonHostInfo::IPV4;
182 }
183 
184 // Writes the given address (with each character representing one dotted
185 // part of an IPv4 address) to the output, and updating |*out_host| to
186 // identify the added portion.
AppendIPv4Address(const unsigned char address[4],CanonOutput * output,url_parse::Component * out_host)187 void AppendIPv4Address(const unsigned char address[4],
188                        CanonOutput* output,
189                        url_parse::Component* out_host) {
190   out_host->begin = output->length();
191   for (int i = 0; i < 4; i++) {
192     char str[16];
193     _itoa_s(address[i], str, 10);
194 
195     for (int ch = 0; str[ch] != 0; ch++)
196       output->push_back(str[ch]);
197 
198     if (i != 3)
199       output->push_back('.');
200   }
201   out_host->len = output->length() - out_host->begin;
202 }
203 
204 // See declaration of IPv4AddressToNumber for documentation.
205 template<typename CHAR>
DoIPv4AddressToNumber(const CHAR * spec,const url_parse::Component & host,unsigned char address[4],int * num_ipv4_components)206 CanonHostInfo::Family DoIPv4AddressToNumber(const CHAR* spec,
207                                             const url_parse::Component& host,
208                                             unsigned char address[4],
209                                             int* num_ipv4_components) {
210   // The identified components. Not all may exist.
211   url_parse::Component components[4];
212   if (!FindIPv4Components(spec, host, components))
213     return CanonHostInfo::NEUTRAL;
214 
215   // Convert existing components to digits. Values up to
216   // |existing_components| will be valid.
217   uint32 component_values[4];
218   int existing_components = 0;
219   for (int i = 0; i < 4; i++) {
220     if (components[i].len <= 0)
221       continue;
222     CanonHostInfo::Family family = IPv4ComponentToNumber(
223         spec, components[i], &component_values[existing_components]);
224 
225     // Stop if we hit an invalid non-empty component.
226     if (family != CanonHostInfo::IPV4)
227       return family;
228 
229     existing_components++;
230   }
231 
232   // Use that sequence of numbers to fill out the 4-component IP address.
233 
234   // First, process all components but the last, while making sure each fits
235   // within an 8-bit field.
236   for (int i = 0; i < existing_components - 1; i++) {
237     if (component_values[i] > kuint8max)
238       return CanonHostInfo::BROKEN;
239     address[i] = static_cast<unsigned char>(component_values[i]);
240   }
241 
242   // Next, consume the last component to fill in the remaining bytes.
243   uint32 last_value = component_values[existing_components - 1];
244   for (int i = 3; i >= existing_components - 1; i--) {
245     address[i] = static_cast<unsigned char>(last_value);
246     last_value >>= 8;
247   }
248 
249   // If the last component has residual bits, report overflow.
250   if (last_value != 0)
251     return CanonHostInfo::BROKEN;
252 
253   // Tell the caller how many components we saw.
254   *num_ipv4_components = existing_components;
255 
256   // Success!
257   return CanonHostInfo::IPV4;
258 }
259 
260 // Return true if we've made a final IPV4/BROKEN decision, false if the result
261 // is NEUTRAL, and we could use a second opinion.
262 template<typename CHAR, typename UCHAR>
DoCanonicalizeIPv4Address(const CHAR * spec,const url_parse::Component & host,CanonOutput * output,CanonHostInfo * host_info)263 bool DoCanonicalizeIPv4Address(const CHAR* spec,
264                                const url_parse::Component& host,
265                                CanonOutput* output,
266                                CanonHostInfo* host_info) {
267   unsigned char address[4];
268   host_info->family = IPv4AddressToNumber(
269       spec, host, address, &host_info->num_ipv4_components);
270 
271   switch (host_info->family) {
272     case CanonHostInfo::IPV4:
273       // Definitely an IPv4 address.
274       AppendIPv4Address(address, output, &host_info->out_host);
275       return true;
276     case CanonHostInfo::BROKEN:
277       // Definitely broken.
278       return true;
279     default:
280       // Could be IPv6 or a hostname.
281       return false;
282   }
283 }
284 
285 // Helper class that describes the main components of an IPv6 input string.
286 // See the following examples to understand how it breaks up an input string:
287 //
288 // [Example 1]: input = "[::aa:bb]"
289 //  ==> num_hex_components = 2
290 //  ==> hex_components[0] = Component(3,2) "aa"
291 //  ==> hex_components[1] = Component(6,2) "bb"
292 //  ==> index_of_contraction = 0
293 //  ==> ipv4_component = Component(0, -1)
294 //
295 // [Example 2]: input = "[1:2::3:4:5]"
296 //  ==> num_hex_components = 5
297 //  ==> hex_components[0] = Component(1,1) "1"
298 //  ==> hex_components[1] = Component(3,1) "2"
299 //  ==> hex_components[2] = Component(6,1) "3"
300 //  ==> hex_components[3] = Component(8,1) "4"
301 //  ==> hex_components[4] = Component(10,1) "5"
302 //  ==> index_of_contraction = 2
303 //  ==> ipv4_component = Component(0, -1)
304 //
305 // [Example 3]: input = "[::ffff:192.168.0.1]"
306 //  ==> num_hex_components = 1
307 //  ==> hex_components[0] = Component(3,4) "ffff"
308 //  ==> index_of_contraction = 0
309 //  ==> ipv4_component = Component(8, 11) "192.168.0.1"
310 //
311 // [Example 4]: input = "[1::]"
312 //  ==> num_hex_components = 1
313 //  ==> hex_components[0] = Component(1,1) "1"
314 //  ==> index_of_contraction = 1
315 //  ==> ipv4_component = Component(0, -1)
316 //
317 // [Example 5]: input = "[::192.168.0.1]"
318 //  ==> num_hex_components = 0
319 //  ==> index_of_contraction = 0
320 //  ==> ipv4_component = Component(8, 11) "192.168.0.1"
321 //
322 struct IPv6Parsed {
323   // Zero-out the parse information.
reseturl_canon::__anon7cfdf62a0111::IPv6Parsed324   void reset() {
325     num_hex_components = 0;
326     index_of_contraction = -1;
327     ipv4_component.reset();
328   }
329 
330   // There can be up to 8 hex components (colon separated) in the literal.
331   url_parse::Component hex_components[8];
332 
333   // The count of hex components present. Ranges from [0,8].
334   int num_hex_components;
335 
336   // The index of the hex component that the "::" contraction precedes, or
337   // -1 if there is no contraction.
338   int index_of_contraction;
339 
340   // The range of characters which are an IPv4 literal.
341   url_parse::Component ipv4_component;
342 };
343 
344 // Parse the IPv6 input string. If parsing succeeded returns true and fills
345 // |parsed| with the information. If parsing failed (because the input is
346 // invalid) returns false.
347 template<typename CHAR, typename UCHAR>
DoParseIPv6(const CHAR * spec,const url_parse::Component & host,IPv6Parsed * parsed)348 bool DoParseIPv6(const CHAR* spec,
349                  const url_parse::Component& host,
350                  IPv6Parsed* parsed) {
351   // Zero-out the info.
352   parsed->reset();
353 
354   if (!host.is_nonempty())
355     return false;
356 
357   // The index for start and end of address range (no brackets).
358   int begin = host.begin;
359   int end = host.end();
360 
361   int cur_component_begin = begin;  // Start of the current component.
362 
363   // Scan through the input, searching for hex components, "::" contractions,
364   // and IPv4 components.
365   for (int i = begin; /* i <= end */; i++) {
366     bool is_colon = spec[i] == ':';
367     bool is_contraction = is_colon && i < end - 1 && spec[i + 1] == ':';
368 
369     // We reached the end of the current component if we encounter a colon
370     // (separator between hex components, or start of a contraction), or end of
371     // input.
372     if (is_colon || i == end) {
373       int component_len = i - cur_component_begin;
374 
375       // A component should not have more than 4 hex digits.
376       if (component_len > 4)
377         return false;
378 
379       // Don't allow empty components.
380       if (component_len == 0) {
381         // The exception is when contractions appear at beginning of the
382         // input or at the end of the input.
383         if (!((is_contraction && i == begin) || (i == end &&
384             parsed->index_of_contraction == parsed->num_hex_components)))
385           return false;
386       }
387 
388       // Add the hex component we just found to running list.
389       if (component_len > 0) {
390         // Can't have more than 8 components!
391         if (parsed->num_hex_components >= 8)
392           return false;
393 
394         parsed->hex_components[parsed->num_hex_components++] =
395             url_parse::Component(cur_component_begin, component_len);
396       }
397     }
398 
399     if (i == end)
400       break;  // Reached the end of the input, DONE.
401 
402     // We found a "::" contraction.
403     if (is_contraction) {
404       // There can be at most one contraction in the literal.
405       if (parsed->index_of_contraction != -1)
406         return false;
407       parsed->index_of_contraction = parsed->num_hex_components;
408       ++i;  // Consume the colon we peeked.
409     }
410 
411     if (is_colon) {
412       // Colons are separators between components, keep track of where the
413       // current component started (after this colon).
414       cur_component_begin = i + 1;
415     } else {
416       if (static_cast<UCHAR>(spec[i]) >= 0x80)
417         return false;  // Not ASCII.
418 
419       if (!IsHexChar(static_cast<unsigned char>(spec[i]))) {
420         // Regular components are hex numbers. It is also possible for
421         // a component to be an IPv4 address in dotted form.
422         if (IsIPv4Char(static_cast<unsigned char>(spec[i]))) {
423           // Since IPv4 address can only appear at the end, assume the rest
424           // of the string is an IPv4 address. (We will parse this separately
425           // later).
426           parsed->ipv4_component = url_parse::Component(
427               cur_component_begin, end - cur_component_begin);
428           break;
429         } else {
430           // The character was neither a hex digit, nor an IPv4 character.
431           return false;
432         }
433       }
434     }
435   }
436 
437   return true;
438 }
439 
440 // Verifies the parsed IPv6 information, checking that the various components
441 // add up to the right number of bits (hex components are 16 bits, while
442 // embedded IPv4 formats are 32 bits, and contractions are placeholdes for
443 // 16 or more bits). Returns true if sizes match up, false otherwise. On
444 // success writes the length of the contraction (if any) to
445 // |out_num_bytes_of_contraction|.
CheckIPv6ComponentsSize(const IPv6Parsed & parsed,int * out_num_bytes_of_contraction)446 bool CheckIPv6ComponentsSize(const IPv6Parsed& parsed,
447                              int* out_num_bytes_of_contraction) {
448   // Each group of four hex digits contributes 16 bits.
449   int num_bytes_without_contraction = parsed.num_hex_components * 2;
450 
451   // If an IPv4 address was embedded at the end, it contributes 32 bits.
452   if (parsed.ipv4_component.is_valid())
453     num_bytes_without_contraction += 4;
454 
455   // If there was a "::" contraction, its size is going to be:
456   // MAX([16bits], [128bits] - num_bytes_without_contraction).
457   int num_bytes_of_contraction = 0;
458   if (parsed.index_of_contraction != -1) {
459     num_bytes_of_contraction = 16 - num_bytes_without_contraction;
460     if (num_bytes_of_contraction < 2)
461       num_bytes_of_contraction = 2;
462   }
463 
464   // Check that the numbers add up.
465   if (num_bytes_without_contraction + num_bytes_of_contraction != 16)
466     return false;
467 
468   *out_num_bytes_of_contraction = num_bytes_of_contraction;
469   return true;
470 }
471 
472 // Converts a hex comonent into a number. This cannot fail since the caller has
473 // already verified that each character in the string was a hex digit, and
474 // that there were no more than 4 characters.
475 template<typename CHAR>
IPv6HexComponentToNumber(const CHAR * spec,const url_parse::Component & component)476 uint16 IPv6HexComponentToNumber(const CHAR* spec,
477                                 const url_parse::Component& component) {
478   DCHECK(component.len <= 4);
479 
480   // Copy the hex string into a C-string.
481   char buf[5];
482   for (int i = 0; i < component.len; ++i)
483     buf[i] = static_cast<char>(spec[component.begin + i]);
484   buf[component.len] = '\0';
485 
486   // Convert it to a number (overflow is not possible, since with 4 hex
487   // characters we can at most have a 16 bit number).
488   return static_cast<uint16>(_strtoui64(buf, NULL, 16));
489 }
490 
491 // Converts an IPv6 address to a 128-bit number (network byte order), returning
492 // true on success. False means that the input was not a valid IPv6 address.
493 template<typename CHAR, typename UCHAR>
DoIPv6AddressToNumber(const CHAR * spec,const url_parse::Component & host,unsigned char address[16])494 bool DoIPv6AddressToNumber(const CHAR* spec,
495                            const url_parse::Component& host,
496                            unsigned char address[16]) {
497   // Make sure the component is bounded by '[' and ']'.
498   int end = host.end();
499   if (!host.is_nonempty() || spec[host.begin] != '[' || spec[end - 1] != ']')
500     return false;
501 
502   // Exclude the square brackets.
503   url_parse::Component ipv6_comp(host.begin + 1, host.len - 2);
504 
505   // Parse the IPv6 address -- identify where all the colon separated hex
506   // components are, the "::" contraction, and the embedded IPv4 address.
507   IPv6Parsed ipv6_parsed;
508   if (!DoParseIPv6<CHAR, UCHAR>(spec, ipv6_comp, &ipv6_parsed))
509     return false;
510 
511   // Do some basic size checks to make sure that the address doesn't
512   // specify more than 128 bits or fewer than 128 bits. This also resolves
513   // how may zero bytes the "::" contraction represents.
514   int num_bytes_of_contraction;
515   if (!CheckIPv6ComponentsSize(ipv6_parsed, &num_bytes_of_contraction))
516     return false;
517 
518   int cur_index_in_address = 0;
519 
520   // Loop through each hex components, and contraction in order.
521   for (int i = 0; i <= ipv6_parsed.num_hex_components; ++i) {
522     // Append the contraction if it appears before this component.
523     if (i == ipv6_parsed.index_of_contraction) {
524       for (int j = 0; j < num_bytes_of_contraction; ++j)
525         address[cur_index_in_address++] = 0;
526     }
527     // Append the hex component's value.
528     if (i != ipv6_parsed.num_hex_components) {
529       // Get the 16-bit value for this hex component.
530       uint16 number = IPv6HexComponentToNumber<CHAR>(
531           spec, ipv6_parsed.hex_components[i]);
532       // Append to |address|, in network byte order.
533       address[cur_index_in_address++] = (number & 0xFF00) >> 8;
534       address[cur_index_in_address++] = (number & 0x00FF);
535     }
536   }
537 
538   // If there was an IPv4 section, convert it into a 32-bit number and append
539   // it to |address|.
540   if (ipv6_parsed.ipv4_component.is_valid()) {
541     // We only allow the embedded IPv4 syntax to be used for "compat" and
542     // "mapped" formats:
543     //     "mapped" ==>  0:0:0:0:0:ffff:<IPv4-literal>
544     //     "compat" ==>  0:0:0:0:0:0000:<IPv4-literal>
545     for (int j = 0; j < 10; ++j) {
546       if (address[j] != 0)
547         return false;
548     }
549     if (!((address[10] == 0 && address[11] == 0) ||
550           (address[10] == 0xFF && address[11] == 0xFF)))
551       return false;
552 
553     // Append the 32-bit number to |address|.
554     int ignored_num_ipv4_components;
555     if (CanonHostInfo::IPV4 !=
556         IPv4AddressToNumber(spec,
557                             ipv6_parsed.ipv4_component,
558                             &address[cur_index_in_address],
559                             &ignored_num_ipv4_components))
560       return false;
561   }
562 
563   return true;
564 }
565 
566 // Searches for the longest sequence of zeros in |address|, and writes the
567 // range into |contraction_range|. The run of zeros must be at least 16 bits,
568 // and if there is a tie the first is chosen.
ChooseIPv6ContractionRange(const unsigned char address[16],url_parse::Component * contraction_range)569 void ChooseIPv6ContractionRange(const unsigned char address[16],
570                                 url_parse::Component* contraction_range) {
571   // The longest run of zeros in |address| seen so far.
572   url_parse::Component max_range;
573 
574   // The current run of zeros in |address| being iterated over.
575   url_parse::Component cur_range;
576 
577   for (int i = 0; i < 16; i += 2) {
578     // Test for 16 bits worth of zero.
579     bool is_zero = (address[i] == 0 && address[i + 1] == 0);
580 
581     if (is_zero) {
582       // Add the zero to the current range (or start a new one).
583       if (!cur_range.is_valid())
584         cur_range = url_parse::Component(i, 0);
585       cur_range.len += 2;
586     }
587 
588     if (!is_zero || i == 14) {
589       // Just completed a run of zeros. If the run is greater than 16 bits,
590       // it is a candidate for the contraction.
591       if (cur_range.len > 2 && cur_range.len > max_range.len) {
592         max_range = cur_range;
593       }
594       cur_range.reset();
595     }
596   }
597   *contraction_range = max_range;
598 }
599 
600 // Return true if we've made a final IPV6/BROKEN decision, false if the result
601 // is NEUTRAL, and we could use a second opinion.
602 template<typename CHAR, typename UCHAR>
DoCanonicalizeIPv6Address(const CHAR * spec,const url_parse::Component & host,CanonOutput * output,CanonHostInfo * host_info)603 bool DoCanonicalizeIPv6Address(const CHAR* spec,
604                                const url_parse::Component& host,
605                                CanonOutput* output,
606                                CanonHostInfo* host_info) {
607   // Turn the IP address into a 128 bit number.
608   unsigned char address[16];
609   if (!IPv6AddressToNumber(spec, host, address)) {
610     // If it's not an IPv6 address, scan for characters that should *only*
611     // exist in an IPv6 address.
612     for (int i = host.begin; i < host.end(); i++) {
613       switch (spec[i]) {
614         case '[':
615         case ']':
616         case ':':
617           host_info->family = CanonHostInfo::BROKEN;
618           return true;
619       }
620     }
621 
622     // No invalid characters.  Could still be IPv4 or a hostname.
623     host_info->family = CanonHostInfo::NEUTRAL;
624     return false;
625   }
626 
627   host_info->out_host.begin = output->length();
628   output->push_back('[');
629 
630   // We will now output the address according to the rules in:
631   // http://tools.ietf.org/html/draft-kawamura-ipv6-text-representation-01#section-4
632 
633   // Start by finding where to place the "::" contraction (if any).
634   url_parse::Component contraction_range;
635   ChooseIPv6ContractionRange(address, &contraction_range);
636 
637   for (int i = 0; i <= 14;) {
638     // We check 2 bytes at a time, from bytes (0, 1) to (14, 15), inclusive.
639     DCHECK(i % 2 == 0);
640     if (i == contraction_range.begin && contraction_range.len > 0) {
641       // Jump over the contraction.
642       if (i == 0)
643         output->push_back(':');
644       output->push_back(':');
645       i = contraction_range.end();
646     } else {
647       // Consume the next 16 bits from |address|.
648       int x = address[i] << 8 | address[i + 1];
649 
650       i += 2;
651 
652       // Stringify the 16 bit number (at most requires 4 hex digits).
653       char str[5];
654       _itoa_s(x, str, 16);
655       for (int ch = 0; str[ch] != 0; ++ch)
656         output->push_back(str[ch]);
657 
658       // Put a colon after each number, except the last.
659       if (i < 16)
660         output->push_back(':');
661     }
662   }
663 
664   output->push_back(']');
665   host_info->out_host.len = output->length() - host_info->out_host.begin;
666 
667   host_info->family = CanonHostInfo::IPV6;
668   return true;
669 }
670 
671 }  // namespace
672 
FindIPv4Components(const char * spec,const url_parse::Component & host,url_parse::Component components[4])673 bool FindIPv4Components(const char* spec,
674                         const url_parse::Component& host,
675                         url_parse::Component components[4]) {
676   return DoFindIPv4Components<char, unsigned char>(spec, host, components);
677 }
678 
FindIPv4Components(const char16 * spec,const url_parse::Component & host,url_parse::Component components[4])679 bool FindIPv4Components(const char16* spec,
680                         const url_parse::Component& host,
681                         url_parse::Component components[4]) {
682   return DoFindIPv4Components<char16, char16>(spec, host, components);
683 }
684 
CanonicalizeIPAddress(const char * spec,const url_parse::Component & host,CanonOutput * output,CanonHostInfo * host_info)685 void CanonicalizeIPAddress(const char* spec,
686                            const url_parse::Component& host,
687                            CanonOutput* output,
688                            CanonHostInfo* host_info) {
689   if (DoCanonicalizeIPv4Address<char, unsigned char>(
690           spec, host, output, host_info))
691     return;
692   if (DoCanonicalizeIPv6Address<char, unsigned char>(
693           spec, host, output, host_info))
694     return;
695 }
696 
CanonicalizeIPAddress(const char16 * spec,const url_parse::Component & host,CanonOutput * output,CanonHostInfo * host_info)697 void CanonicalizeIPAddress(const char16* spec,
698                            const url_parse::Component& host,
699                            CanonOutput* output,
700                            CanonHostInfo* host_info) {
701   if (DoCanonicalizeIPv4Address<char16, char16>(
702           spec, host, output, host_info))
703     return;
704   if (DoCanonicalizeIPv6Address<char16, char16>(
705           spec, host, output, host_info))
706     return;
707 }
708 
IPv4AddressToNumber(const char * spec,const url_parse::Component & host,unsigned char address[4],int * num_ipv4_components)709 CanonHostInfo::Family IPv4AddressToNumber(const char* spec,
710                                           const url_parse::Component& host,
711                                           unsigned char address[4],
712                                           int* num_ipv4_components) {
713   return DoIPv4AddressToNumber<char>(spec, host, address, num_ipv4_components);
714 }
715 
IPv4AddressToNumber(const char16 * spec,const url_parse::Component & host,unsigned char address[4],int * num_ipv4_components)716 CanonHostInfo::Family IPv4AddressToNumber(const char16* spec,
717                                           const url_parse::Component& host,
718                                           unsigned char address[4],
719                                           int* num_ipv4_components) {
720   return DoIPv4AddressToNumber<char16>(
721       spec, host, address, num_ipv4_components);
722 }
723 
IPv6AddressToNumber(const char * spec,const url_parse::Component & host,unsigned char address[16])724 bool IPv6AddressToNumber(const char* spec,
725                          const url_parse::Component& host,
726                          unsigned char address[16]) {
727   return DoIPv6AddressToNumber<char, unsigned char>(spec, host, address);
728 }
729 
IPv6AddressToNumber(const char16 * spec,const url_parse::Component & host,unsigned char address[16])730 bool IPv6AddressToNumber(const char16* spec,
731                          const url_parse::Component& host,
732                          unsigned char address[16]) {
733   return DoIPv6AddressToNumber<char16, char16>(spec, host, address);
734 }
735 
736 
737 }  // namespace url_canon
738