Code:
/ FX-1434 / FX-1434 / 1.0 / untmp / whidbey / REDBITS / ndp / fx / src / Net / System / _IPv6Address.cs / 1 / _IPv6Address.cs
//------------------------------------------------------------------------------
//
// Copyright (c) Microsoft Corporation. All rights reserved.
//
//-----------------------------------------------------------------------------
namespace System {
// The class designed as to keep minimal the working set of Uri class.
// The idea is to stay with static helper methods and strings
internal class IPv6AddressHelper{
// fields
private const int NumberOfLabels = 8;
private const string CanonicalNumberFormat = "{0:X4}";
private IPv6AddressHelper() {
}
// methods
internal static string ParseCanonicalName(string str, int start, ref bool isLoopback, ref string scopeId) {
unsafe {
ushort *numbers = stackalloc ushort[NumberOfLabels];
// optimized zeroing of 8 shorts = 2 longs
((long*)numbers)[0] = 0L;
((long*)numbers)[1] = 0L;
isLoopback = Parse(str, numbers, start, ref scopeId);
return CreateCanonicalName(numbers);
}
}
unsafe private static string CreateCanonicalName(ushort *numbers) {
return '[' + String.Format(CanonicalNumberFormat, numbers[0]) + ':'
+ String.Format(CanonicalNumberFormat, numbers[1]) + ':'
+ String.Format(CanonicalNumberFormat, numbers[2]) + ':'
+ String.Format(CanonicalNumberFormat, numbers[3]) + ':'
+ String.Format(CanonicalNumberFormat, numbers[4]) + ':'
+ String.Format(CanonicalNumberFormat, numbers[5]) + ':'
+ String.Format(CanonicalNumberFormat, numbers[6]) + ':'
+ String.Format(CanonicalNumberFormat, numbers[7]) + ']';
}
//
// IsValid
//
// Determine whether a name is a valid IPv6 address. Rules are:
//
// * 8 groups of 16-bit hex numbers, separated by ':'
// * a *single* run of zeros can be compressed using the symbol '::'
// * an optional string of a ScopeID delimited by '%'
// * an optional (last) 1 or 2 character prefix length field delimited by '/'
// * the last 32 bits in an address can be represented as an IPv4 address
//
// Inputs:
// name
// Domain name field of a URI to check for pattern match with
// IPv6 address
//
// Outputs:
// Nothing
//
// Assumes:
// the correct name is terminated by ']' character
//
// Returns:
// true if has IPv6 format, else false
//
// Throws:
// Nothing
//
// Remarks: MUST NOT be used unless all input indexes are are verified and trusted.
// start must be next to '[' position, or error is reported
internal unsafe static bool IsValid(char* name, int start, ref int end) {
int sequenceCount = 0;
int sequenceLength = 0;
bool haveCompressor = false;
bool haveIPv4Address = false;
bool havePrefix = false;
bool expectingNumber = true;
int lastSequence = 1;
int i;
for (i = start; i < end; ++i) {
if (havePrefix ? (name[i] >= '0' && name[i] <= '9') : Uri.IsHexDigit(name[i])) {
++sequenceLength;
expectingNumber = false;
} else {
if (sequenceLength > 4) {
return false;
}
if (sequenceLength != 0) {
++sequenceCount;
lastSequence = i - sequenceLength;
}
switch (name[i]) {
case '%': while (true) {
//accept anything in scopeID
if (++i == end) {
// no closing ']', fail
return false;
}
if (name[i] == ']') {
goto case ']';
}
else if (name[i] == '/') {
goto case '/';
}
}
case ']': start = i;
i = end;
//this will make i = end+1
continue;
case ':':
if ((i > 0) && (name[i - 1] == ':')) {
if (haveCompressor) {
//
// can only have one per IPv6 address
//
return false;
}
haveCompressor = true;
expectingNumber = false;
} else {
expectingNumber = true;
}
break;
case '/':
if ((sequenceCount == 0) || havePrefix) {
return false;
}
havePrefix = true;
expectingNumber = true;
break;
case '.':
if (haveIPv4Address) {
return false;
}
i = end;
if (!IPv4AddressHelper.IsValid(name, lastSequence, ref i, true, false)) {
return false;
}
// ipv4 address takes 2 slots in ipv6 address, one was just counted meeting the '.'
++sequenceCount;
haveIPv4Address = true;
--i; // it will be incremented back on the next loop
break;
default:
return false;
}
sequenceLength = 0;
}
}
//
// if the last token was a prefix, check number of digits
//
if (havePrefix && ((sequenceLength < 1) || (sequenceLength > 2))) {
return false;
}
//
// these sequence counts are -1 because it is implied in end-of-sequence
//
int expectedSequenceCount = 8 + (havePrefix ? 1 : 0);
if (!expectingNumber && (sequenceLength <= 4) && (haveCompressor ? (sequenceCount < expectedSequenceCount) : (sequenceCount == expectedSequenceCount)))
{
if (i == end + 1)
{
// ']' was found
end = start+1;
return true;
}
return false;
}
return false;
}
//
// Parse
//
// Convert this IPv6 address into a sequence of 8 16-bit numbers
//
// Inputs:
// Name
// The validated IPv6 address
//
// Outputs:
// numbers
// Array filled in with the numbers in the IPv6 groups
//
// PrefixLength
// Set to the number after the prefix separator (/) if found
//
// Assumes:
// has been validated and contains only hex digits in groups of
// 16-bit numbers, the characters ':' and '/', and a possible IPv4
// address
//
// Returns:
// true if this is a loopback, false otherwise. There is no falure indication as the sting must be a valid one.
//
// Throws:
// Nothing
//
unsafe internal static bool Parse(string address, ushort *numbers, int start, ref string scopeId) {
int number = 0;
int index = 0;
int compressorIndex = -1;
bool numberIsValid = true;
//This used to be a class instance member but have not been used so far
int PrefixLength = 0;
if (address[start] == '[') {
++start;
}
for (int i = start; i < address.Length && address[i] != ']'; ) {
switch (address[i]) {
case '%':
if (numberIsValid) {
numbers[index++] = (ushort)number;
numberIsValid = false;
}
start = i;
for (++i; address[i] != ']' && address[i] != '/'; ++i) {
;
}
scopeId = address.Substring(start, i-start);
// ignore prefix if any
for (; address[i] != ']'; ++i) {
;
}
break;
case ':':
numbers[index++] = (ushort)number;
number = 0;
++i;
if (address[i] == ':') {
compressorIndex = index;
++i;
} else if ((compressorIndex < 0) && (index < 6)) {
//
// no point checking for IPv4 address if we don't
// have a compressor or we haven't seen 6 16-bit
// numbers yet
//
break;
}
//
// check to see if the upcoming number is really an IPv4
// address. If it is, convert it to 2 ushort numbers
//
for (int j = i; (address[j] != ']') &&
(address[j] != ':') &&
(address[j] != '%') &&
(address[j] != '/') &&
(j < i + 4); ++j) {
if (address[j] == '.') {
//
// we have an IPv4 address. Find the end of it:
// we know that since we have a valid IPv6
// address, the only things that will terminate
// the IPv4 address are the prefix delimiter '/'
// or the end-of-string (which we conveniently
// delimited with ']')
//
while ((address[j] != ']') && (address[j] != '/') && (address[j] != '%')) {
++j;
}
number = IPv4AddressHelper.ParseHostNumber(address, i, j);
numbers[index++] = (ushort)(number>>16);
numbers[index++] = (ushort)number;
i = j;
//
// set this to avoid adding another number to
// the array if there's a prefix
//
number = 0;
numberIsValid = false;
break;
}
}
break;
case '/':
if (numberIsValid) {
numbers[index++] = (ushort)number;
numberIsValid = false;
}
//
// since we have a valid IPv6 address string, the prefix
// length is the last token in the string
//
for (++i; address[i] != ']'; ++i) {
PrefixLength = PrefixLength * 10 + (address[i] - '0');
}
break;
default:
number = number * 16 + Uri.FromHex(address[i++]);
break;
}
}
//
// add number to the array if its not the prefix length or part of
// an IPv4 address that's already been handled
//
if (numberIsValid) {
numbers[index++] = (ushort)number;
}
//
// if we had a compressor sequence ("::") then we need to expand the
// numbers array
//
if (compressorIndex > 0) {
int toIndex = NumberOfLabels - 1;
int fromIndex = index - 1;
for (int i = index - compressorIndex; i > 0 ; --i) {
numbers[toIndex--] = numbers[fromIndex];
numbers[fromIndex--] = 0;
}
}
//
// is the address loopback? Loopback is defined as one of:
//
// 0:0:0:0:0:0:0:1
// 0:0:0:0:0:0:127.0.0.1 == 0:0:0:0:0:0:7F00:0001
// 0:0:0:0:0:FFFF:127.0.0.1 == 0:0:0:0:0:FFFF:7F00:0001
//
return ((numbers[0] == 0)
&& (numbers[1] == 0)
&& (numbers[2] == 0)
&& (numbers[3] == 0)
&& (numbers[4] == 0))
&& (((numbers[5] == 0)
&& (numbers[6] == 0)
&& (numbers[7] == 1))
|| (((numbers[6] == 0x7F00)
&& (numbers[7] == 0x0001))
&& ((numbers[5] == 0)
|| (numbers[5] == 0xFFFF))));
}
}
}
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