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| 1 | +package core.framework.internal.web.http; |
| 2 | + |
| 3 | +import java.util.Arrays; |
| 4 | +import java.util.Comparator; |
| 5 | +import java.util.List; |
| 6 | + |
| 7 | +public class IPv6Ranges { |
| 8 | + static boolean withinRanges(LongLong[] ranges, LongLong value) { |
| 9 | + int low = 0; |
| 10 | + int high = ranges.length - 1; |
| 11 | + |
| 12 | + if (value.compareTo(ranges[low]) < 0 || value.compareTo(ranges[high]) > 0) return false; |
| 13 | + |
| 14 | + while (high - low > 1) { |
| 15 | + int middle = (low + high) >>> 1; |
| 16 | + LongLong middleValue = ranges[middle]; |
| 17 | + |
| 18 | + int comparison = middleValue.compareTo(value); |
| 19 | + if (comparison < 0) |
| 20 | + low = middle; |
| 21 | + else if (comparison > 0) |
| 22 | + high = middle; |
| 23 | + else { |
| 24 | + return true; |
| 25 | + } |
| 26 | + } |
| 27 | + return low % 2 == 0; |
| 28 | + } |
| 29 | + |
| 30 | + static LongLong[] mergeRanges(LongLong[][] ranges) { |
| 31 | + Arrays.sort(ranges, Comparator.comparing(a -> a[0])); |
| 32 | + LongLong[] results = new LongLong[ranges.length * 2]; |
| 33 | + int index = 0; |
| 34 | + for (LongLong[] range : ranges) { |
| 35 | + if (index > 1 && results[index - 1].compareTo(range[0]) >= 0) { |
| 36 | + if (results[index - 1].compareTo(range[1]) < 0) { |
| 37 | + results[index - 1] = range[1]; |
| 38 | + } |
| 39 | + } else { |
| 40 | + results[index++] = range[0]; |
| 41 | + results[index++] = range[1]; |
| 42 | + } |
| 43 | + } |
| 44 | + if (index < results.length) { |
| 45 | + return Arrays.copyOf(results, index); |
| 46 | + } else { |
| 47 | + return results; |
| 48 | + } |
| 49 | + } |
| 50 | + |
| 51 | + static LongLong toLongLong(byte[] address) { |
| 52 | + if (address.length != 16) throw new Error("not ipv6 address, address=" + Arrays.toString(address)); |
| 53 | + |
| 54 | + long high = 0; |
| 55 | + high |= (long) (address[0] & 0xFF) << 56; |
| 56 | + high |= (long) (address[1] & 0xFF) << 48; |
| 57 | + high |= (long) (address[2] & 0xFF) << 40; |
| 58 | + high |= (long) (address[3] & 0xFF) << 32; |
| 59 | + high |= (long) (address[4] & 0xFF) << 24; |
| 60 | + high |= (long) (address[5] & 0xFF) << 16; |
| 61 | + high |= (long) (address[6] & 0xFF) << 8; |
| 62 | + high |= address[7] & 0xFF; |
| 63 | + |
| 64 | + long low = 0; |
| 65 | + low |= (long) (address[8] & 0xFF) << 56; |
| 66 | + low |= (long) (address[9] & 0xFF) << 48; |
| 67 | + low |= (long) (address[10] & 0xFF) << 40; |
| 68 | + low |= (long) (address[11] & 0xFF) << 32; |
| 69 | + low |= (long) (address[12] & 0xFF) << 24; |
| 70 | + low |= (long) (address[13] & 0xFF) << 16; |
| 71 | + low |= (long) (address[14] & 0xFF) << 8; |
| 72 | + low |= address[15] & 0xFF; |
| 73 | + |
| 74 | + return new LongLong(high, low); |
| 75 | + } |
| 76 | + |
| 77 | + private final LongLong[] ranges; |
| 78 | + |
| 79 | + public IPv6Ranges(List<String> cidrs) { |
| 80 | + LongLong[][] ranges = new LongLong[cidrs.size()][]; |
| 81 | + int index = 0; |
| 82 | + for (String cidr : cidrs) { |
| 83 | + LongLong[] range = comparableIPRanges(cidr); |
| 84 | + ranges[index++] = range; |
| 85 | + } |
| 86 | + this.ranges = mergeRanges(ranges); |
| 87 | + } |
| 88 | + |
| 89 | + private LongLong[] comparableIPRanges(String cidr) { |
| 90 | + int index = cidr.indexOf('/'); |
| 91 | + if (index <= 0 || index >= cidr.length() - 1) throw new Error("invalid cidr, value=" + cidr); |
| 92 | + LongLong address = toLongLong(IPv4Ranges.address(cidr.substring(0, index))); |
| 93 | + int maskBits = Integer.parseInt(cidr.substring(index + 1)); |
| 94 | + |
| 95 | + LongLong rangeStart; |
| 96 | + LongLong rangeEnd; |
| 97 | + if (maskBits == 0) { |
| 98 | + rangeStart = new LongLong(0L, 0L); |
| 99 | + rangeEnd = new LongLong(-1L, -1L); |
| 100 | + } else if (maskBits <= 64) { |
| 101 | + long highMask = -1L << (64 - maskBits); |
| 102 | + rangeStart = new LongLong(address.high & highMask, 0L); |
| 103 | + rangeEnd = new LongLong(rangeStart.high | ~highMask, -1L); |
| 104 | + } else { |
| 105 | + long lowMask = -1L << (128 - maskBits); |
| 106 | + rangeStart = new LongLong(address.high, address.low & lowMask); |
| 107 | + rangeEnd = new LongLong(address.high, rangeStart.low | ~lowMask); |
| 108 | + } |
| 109 | + |
| 110 | + return new LongLong[]{rangeStart.toSortable(), rangeEnd.toSortable()}; |
| 111 | + } |
| 112 | + |
| 113 | + public boolean matches(byte[] address) { |
| 114 | + if (ranges.length == 0) return false; |
| 115 | + if (address.length != 16) return false; |
| 116 | + |
| 117 | + LongLong comparableIP = toLongLong(address).toSortable(); |
| 118 | + return withinRanges(ranges, comparableIP); |
| 119 | + } |
| 120 | + |
| 121 | + // high,low are used to represent a 128-bit IPv6 address as two 64-bit long values |
| 122 | + record LongLong(long high, long low) implements Comparable<LongLong> { |
| 123 | + // with address ^ MIN_VALUE, it converts binary presentation to sortable number form (due to java doesn't have unsigned number type) |
| 124 | + // 0.0.0.0 => MIN_VALUE (00000000.0.0.0 => 10000000.0.0.0) |
| 125 | + // 127.255.255.255 => -1 (01111111.11111111.11111111.11111111 => 11111111.11111111.11111111.11111111) |
| 126 | + // 128.0.0.0 => 0 (10000000.0.0.0 => 00000000.0.0.0) |
| 127 | + // 255.255.255.255 => MAX_VALUE (11111111.11111111.11111111.11111111 => 01111111.11111111.11111111.11111111) |
| 128 | + LongLong toSortable() { |
| 129 | + return new LongLong(high ^ Long.MIN_VALUE, low ^ Long.MIN_VALUE); |
| 130 | + } |
| 131 | + |
| 132 | + @Override |
| 133 | + public int compareTo(LongLong other) { |
| 134 | + int result = Long.compare(high, other.high); |
| 135 | + return result != 0 ? result : Long.compare(low, other.low); |
| 136 | + } |
| 137 | + } |
| 138 | +} |
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