315 lines
9.6 KiB
C++
315 lines
9.6 KiB
C++
/*
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* Copyright 2004 The WebRTC Project Authors. All rights reserved.
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*
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* Use of this source code is governed by a BSD-style license
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* that can be found in the LICENSE file in the root of the source
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* tree. An additional intellectual property rights grant can be found
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* in the file PATENTS. All contributing project authors may
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* be found in the AUTHORS file in the root of the source tree.
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*/
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#include "rtc_base/win32.h"
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#include <winsock2.h>
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#include <ws2tcpip.h>
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#include <algorithm>
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#include "rtc_base/arraysize.h"
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#include "rtc_base/byte_order.h"
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#include "rtc_base/checks.h"
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#include "rtc_base/logging.h"
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#include "rtc_base/string_utils.h"
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namespace rtc {
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// Helper function declarations for inet_ntop/inet_pton.
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static const char* inet_ntop_v4(const void* src, char* dst, socklen_t size);
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static const char* inet_ntop_v6(const void* src, char* dst, socklen_t size);
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static int inet_pton_v4(const char* src, void* dst);
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static int inet_pton_v6(const char* src, void* dst);
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// Implementation of inet_ntop (create a printable representation of an
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// ip address). XP doesn't have its own inet_ntop, and
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// WSAAddressToString requires both IPv6 to be installed and for Winsock
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// to be initialized.
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const char* win32_inet_ntop(int af,
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const void* src,
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char* dst,
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socklen_t size) {
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if (!src || !dst) {
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return nullptr;
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}
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switch (af) {
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case AF_INET: {
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return inet_ntop_v4(src, dst, size);
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}
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case AF_INET6: {
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return inet_ntop_v6(src, dst, size);
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}
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}
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return nullptr;
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}
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// As above, but for inet_pton. Implements inet_pton for v4 and v6.
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// Note that our inet_ntop will output normal 'dotted' v4 addresses only.
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int win32_inet_pton(int af, const char* src, void* dst) {
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if (!src || !dst) {
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return 0;
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}
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if (af == AF_INET) {
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return inet_pton_v4(src, dst);
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} else if (af == AF_INET6) {
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return inet_pton_v6(src, dst);
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}
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return -1;
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}
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// Helper function for inet_ntop for IPv4 addresses.
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// Outputs "dotted-quad" decimal notation.
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const char* inet_ntop_v4(const void* src, char* dst, socklen_t size) {
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if (size < INET_ADDRSTRLEN) {
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return nullptr;
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}
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const struct in_addr* as_in_addr =
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reinterpret_cast<const struct in_addr*>(src);
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snprintf(dst, size, "%d.%d.%d.%d", as_in_addr->S_un.S_un_b.s_b1,
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as_in_addr->S_un.S_un_b.s_b2, as_in_addr->S_un.S_un_b.s_b3,
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as_in_addr->S_un.S_un_b.s_b4);
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return dst;
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}
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// Helper function for inet_ntop for IPv6 addresses.
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const char* inet_ntop_v6(const void* src, char* dst, socklen_t size) {
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if (size < INET6_ADDRSTRLEN) {
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return nullptr;
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}
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const uint16_t* as_shorts = reinterpret_cast<const uint16_t*>(src);
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int runpos[8];
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int current = 1;
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int max = 0;
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int maxpos = -1;
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int run_array_size = arraysize(runpos);
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// Run over the address marking runs of 0s.
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for (int i = 0; i < run_array_size; ++i) {
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if (as_shorts[i] == 0) {
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runpos[i] = current;
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if (current > max) {
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maxpos = i;
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max = current;
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}
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++current;
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} else {
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runpos[i] = -1;
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current = 1;
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}
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}
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if (max > 0) {
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int tmpmax = maxpos;
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// Run back through, setting -1 for all but the longest run.
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for (int i = run_array_size - 1; i >= 0; i--) {
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if (i > tmpmax) {
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runpos[i] = -1;
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} else if (runpos[i] == -1) {
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// We're less than maxpos, we hit a -1, so the 'good' run is done.
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// Setting tmpmax -1 means all remaining positions get set to -1.
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tmpmax = -1;
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}
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}
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}
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char* cursor = dst;
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// Print IPv4 compatible and IPv4 mapped addresses using the IPv4 helper.
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// These addresses have an initial run of either eight zero-bytes followed
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// by 0xFFFF, or an initial run of ten zero-bytes.
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if (runpos[0] == 1 &&
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(maxpos == 5 || (maxpos == 4 && as_shorts[5] == 0xFFFF))) {
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*cursor++ = ':';
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*cursor++ = ':';
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if (maxpos == 4) {
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cursor += snprintf(cursor, INET6_ADDRSTRLEN - 2, "ffff:");
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}
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const struct in_addr* as_v4 =
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reinterpret_cast<const struct in_addr*>(&(as_shorts[6]));
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inet_ntop_v4(as_v4, cursor,
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static_cast<socklen_t>(INET6_ADDRSTRLEN - (cursor - dst)));
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} else {
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for (int i = 0; i < run_array_size; ++i) {
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if (runpos[i] == -1) {
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cursor += snprintf(cursor, INET6_ADDRSTRLEN - (cursor - dst), "%x",
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NetworkToHost16(as_shorts[i]));
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if (i != 7 && runpos[i + 1] != 1) {
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*cursor++ = ':';
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}
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} else if (runpos[i] == 1) {
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// Entered the run; print the colons and skip the run.
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*cursor++ = ':';
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*cursor++ = ':';
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i += (max - 1);
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}
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}
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}
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return dst;
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}
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// Helper function for inet_pton for IPv4 addresses.
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// `src` points to a character string containing an IPv4 network address in
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// dotted-decimal format, "ddd.ddd.ddd.ddd", where ddd is a decimal number
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// of up to three digits in the range 0 to 255.
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// The address is converted and copied to dst,
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// which must be sizeof(struct in_addr) (4) bytes (32 bits) long.
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int inet_pton_v4(const char* src, void* dst) {
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const int kIpv4AddressSize = 4;
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int found = 0;
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const char* src_pos = src;
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unsigned char result[kIpv4AddressSize] = {0};
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while (*src_pos != '\0') {
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// strtol won't treat whitespace characters in the begining as an error,
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// so check to ensure this is started with digit before passing to strtol.
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if (!isdigit(*src_pos)) {
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return 0;
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}
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char* end_pos;
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long value = strtol(src_pos, &end_pos, 10);
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if (value < 0 || value > 255 || src_pos == end_pos) {
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return 0;
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}
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++found;
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if (found > kIpv4AddressSize) {
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return 0;
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}
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result[found - 1] = static_cast<unsigned char>(value);
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src_pos = end_pos;
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if (*src_pos == '.') {
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// There's more.
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++src_pos;
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} else if (*src_pos != '\0') {
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// If it's neither '.' nor '\0' then return fail.
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return 0;
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}
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}
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if (found != kIpv4AddressSize) {
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return 0;
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}
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memcpy(dst, result, sizeof(result));
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return 1;
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}
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// Helper function for inet_pton for IPv6 addresses.
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int inet_pton_v6(const char* src, void* dst) {
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// sscanf will pick any other invalid chars up, but it parses 0xnnnn as hex.
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// Check for literal x in the input string.
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const char* readcursor = src;
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char c = *readcursor++;
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while (c) {
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if (c == 'x') {
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return 0;
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}
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c = *readcursor++;
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}
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readcursor = src;
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struct in6_addr an_addr;
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memset(&an_addr, 0, sizeof(an_addr));
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uint16_t* addr_cursor = reinterpret_cast<uint16_t*>(&an_addr.s6_addr[0]);
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uint16_t* addr_end = reinterpret_cast<uint16_t*>(&an_addr.s6_addr[16]);
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bool seencompressed = false;
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// Addresses that start with "::" (i.e., a run of initial zeros) or
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// "::ffff:" can potentially be IPv4 mapped or compatibility addresses.
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// These have dotted-style IPv4 addresses on the end (e.g. "::192.168.7.1").
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if (*readcursor == ':' && *(readcursor + 1) == ':' &&
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*(readcursor + 2) != 0) {
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// Check for periods, which we'll take as a sign of v4 addresses.
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const char* addrstart = readcursor + 2;
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if (strchr(addrstart, '.')) {
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const char* colon = strchr(addrstart, ':');
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if (colon) {
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uint16_t a_short;
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int bytesread = 0;
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if (sscanf(addrstart, "%hx%n", &a_short, &bytesread) != 1 ||
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a_short != 0xFFFF || bytesread != 4) {
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// Colons + periods means has to be ::ffff:a.b.c.d. But it wasn't.
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return 0;
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} else {
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an_addr.s6_addr[10] = 0xFF;
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an_addr.s6_addr[11] = 0xFF;
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addrstart = colon + 1;
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}
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}
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struct in_addr v4;
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if (inet_pton_v4(addrstart, &v4.s_addr)) {
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memcpy(&an_addr.s6_addr[12], &v4, sizeof(v4));
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memcpy(dst, &an_addr, sizeof(an_addr));
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return 1;
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} else {
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// Invalid v4 address.
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return 0;
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}
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}
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}
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// For addresses without a trailing IPv4 component ('normal' IPv6 addresses).
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while (*readcursor != 0 && addr_cursor < addr_end) {
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if (*readcursor == ':') {
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if (*(readcursor + 1) == ':') {
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if (seencompressed) {
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// Can only have one compressed run of zeroes ("::") per address.
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return 0;
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}
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// Hit a compressed run. Count colons to figure out how much of the
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// address is skipped.
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readcursor += 2;
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const char* coloncounter = readcursor;
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int coloncount = 0;
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if (*coloncounter == 0) {
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// Special case - trailing ::.
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addr_cursor = addr_end;
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} else {
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while (*coloncounter) {
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if (*coloncounter == ':') {
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++coloncount;
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}
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++coloncounter;
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}
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// (coloncount + 1) is the number of shorts left in the address.
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// If this number is greater than the number of available shorts, the
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// address is malformed.
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if (coloncount + 1 > addr_end - addr_cursor) {
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return 0;
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}
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addr_cursor = addr_end - (coloncount + 1);
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seencompressed = true;
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}
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} else {
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++readcursor;
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}
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} else {
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uint16_t word;
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int bytesread = 0;
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if (sscanf(readcursor, "%4hx%n", &word, &bytesread) != 1) {
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return 0;
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} else {
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*addr_cursor = HostToNetwork16(word);
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++addr_cursor;
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readcursor += bytesread;
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if (*readcursor != ':' && *readcursor != '\0') {
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return 0;
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}
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}
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}
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}
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if (*readcursor != '\0' || addr_cursor < addr_end) {
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// Catches addresses too short or too long.
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return 0;
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}
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memcpy(dst, &an_addr, sizeof(an_addr));
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return 1;
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}
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} // namespace rtc
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