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// Copyright 2013 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifdef UNSAFE_BUFFERS_BUILD
// TODO(crbug.com/350788890): Remove this and spanify to fix the errors.
#pragma allow_unsafe_buffers
#endif
#include "url/url_canon_ip.h"
#include <stdint.h>
#include <stdlib.h>
#include <limits>
#include "base/check.h"
#include "url/url_canon_internal.h"
#include "url/url_features.h"
namespace url {
namespace {
// Return true if we've made a final IPV4/BROKEN decision, false if the result
// is NEUTRAL, and we could use a second opinion.
template<typename CHAR, typename UCHAR>
bool DoCanonicalizeIPv4Address(const CHAR* spec,
const Component& host,
CanonOutput* output,
CanonHostInfo* host_info) {
host_info->family = IPv4AddressToNumber(
spec, host, host_info->address, &host_info->num_ipv4_components);
switch (host_info->family) {
case CanonHostInfo::IPV4:
// Definitely an IPv4 address.
host_info->out_host.begin = output->length();
AppendIPv4Address(host_info->address, output);
host_info->out_host.len = output->length() - host_info->out_host.begin;
return true;
case CanonHostInfo::BROKEN:
// Definitely broken.
return true;
default:
// Could be IPv6 or a hostname.
return false;
}
}
// Searches for the longest sequence of zeros in |address|, and writes the
// range into |contraction_range|. The run of zeros must be at least 16 bits,
// and if there is a tie the first is chosen.
void ChooseIPv6ContractionRange(const unsigned char address[16],
Component* contraction_range) {
// The longest run of zeros in |address| seen so far.
Component max_range;
// The current run of zeros in |address| being iterated over.
Component cur_range;
for (int i = 0; i < 16; i += 2) {
// Test for 16 bits worth of zero.
bool is_zero = (address[i] == 0 && address[i + 1] == 0);
if (is_zero) {
// Add the zero to the current range (or start a new one).
if (!cur_range.is_valid())
cur_range = Component(i, 0);
cur_range.len += 2;
}
if (!is_zero || i == 14) {
// Just completed a run of zeros. If the run is greater than 16 bits,
// it is a candidate for the contraction.
if (cur_range.len > 2 && cur_range.len > max_range.len) {
max_range = cur_range;
}
cur_range.reset();
}
}
*contraction_range = max_range;
}
// Return true if we've made a final IPV6/BROKEN decision, false if the result
// is NEUTRAL, and we could use a second opinion.
template<typename CHAR, typename UCHAR>
bool DoCanonicalizeIPv6Address(const CHAR* spec,
const Component& host,
CanonOutput* output,
CanonHostInfo* host_info) {
// Turn the IP address into a 128 bit number.
if (!IPv6AddressToNumber(spec, host, host_info->address)) {
// If it's not an IPv6 address, scan for characters that should *only*
// exist in an IPv6 address.
for (int i = host.begin; i < host.end(); i++) {
switch (spec[i]) {
case '[':
case ']':
case ':':
host_info->family = CanonHostInfo::BROKEN;
return true;
}
}
// No invalid characters. Could still be IPv4 or a hostname.
host_info->family = CanonHostInfo::NEUTRAL;
return false;
}
host_info->out_host.begin = output->length();
output->push_back('[');
AppendIPv6Address(host_info->address, output);
output->push_back(']');
host_info->out_host.len = output->length() - host_info->out_host.begin;
host_info->family = CanonHostInfo::IPV6;
return true;
}
} // namespace
void AppendIPv4Address(const unsigned char address[4], CanonOutput* output) {
for (int i = 0; i < 4; i++) {
char str[16];
_itoa_s(address[i], str, 10);
for (int ch = 0; str[ch] != 0; ch++)
output->push_back(str[ch]);
if (i != 3)
output->push_back('.');
}
}
void AppendIPv6Address(const unsigned char address[16], CanonOutput* output) {
// We will output the address according to the rules in:
// http://tools.ietf.org/html/draft-kawamura-ipv6-text-representation-01#section-4
// Start by finding where to place the "::" contraction (if any).
Component contraction_range;
ChooseIPv6ContractionRange(address, &contraction_range);
for (int i = 0; i <= 14;) {
// We check 2 bytes at a time, from bytes (0, 1) to (14, 15), inclusive.
DCHECK(i % 2 == 0);
if (i == contraction_range.begin && contraction_range.len > 0) {
// Jump over the contraction.
if (i == 0)
output->push_back(':');
output->push_back(':');
i = contraction_range.end();
} else {
// Consume the next 16 bits from |address|.
int x = address[i] << 8 | address[i + 1];
i += 2;
// Stringify the 16 bit number (at most requires 4 hex digits).
char str[5];
_itoa_s(x, str, 16);
for (int ch = 0; str[ch] != 0; ++ch)
output->push_back(str[ch]);
// Put a colon after each number, except the last.
if (i < 16)
output->push_back(':');
}
}
}
void CanonicalizeIPAddress(const char* spec,
const Component& host,
CanonOutput* output,
CanonHostInfo* host_info) {
if (DoCanonicalizeIPv4Address<char, unsigned char>(
spec, host, output, host_info))
return;
if (DoCanonicalizeIPv6Address<char, unsigned char>(
spec, host, output, host_info))
return;
}
void CanonicalizeIPAddress(const char16_t* spec,
const Component& host,
CanonOutput* output,
CanonHostInfo* host_info) {
if (DoCanonicalizeIPv4Address<char16_t, char16_t>(spec, host, output,
host_info))
return;
if (DoCanonicalizeIPv6Address<char16_t, char16_t>(spec, host, output,
host_info))
return;
}
void CanonicalizeIPv6Address(const char* spec,
const Component& host,
CanonOutput& output,
CanonHostInfo& host_info) {
DoCanonicalizeIPv6Address<char, unsigned char>(spec, host, &output,
&host_info);
}
void CanonicalizeIPv6Address(const char16_t* spec,
const Component& host,
CanonOutput& output,
CanonHostInfo& host_info) {
DoCanonicalizeIPv6Address<char16_t, char16_t>(spec, host, &output,
&host_info);
}
} // namespace url
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