Code:
/ DotNET / DotNET / 8.0 / 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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