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| 1 | +// Copyright 2023 The Go Authors. All rights reserved. |
| 2 | +// Use of this source code is governed by a BSD-style |
| 3 | +// license that can be found in the LICENSE file. |
| 4 | + |
| 5 | +package quic |
| 6 | + |
| 7 | +import ( |
| 8 | + "bytes" |
| 9 | + "encoding/binary" |
| 10 | + "testing" |
| 11 | +) |
| 12 | + |
| 13 | +func TestDecodePacketNumber(t *testing.T) { |
| 14 | + for _, test := range []struct { |
| 15 | + largest packetNumber |
| 16 | + truncated packetNumber |
| 17 | + want packetNumber |
| 18 | + size int |
| 19 | + }{{ |
| 20 | + largest: 0, |
| 21 | + truncated: 1, |
| 22 | + size: 4, |
| 23 | + want: 1, |
| 24 | + }, { |
| 25 | + largest: 0, |
| 26 | + truncated: 0, |
| 27 | + size: 1, |
| 28 | + want: 0, |
| 29 | + }, { |
| 30 | + largest: 0x00, |
| 31 | + truncated: 0x01, |
| 32 | + size: 1, |
| 33 | + want: 0x01, |
| 34 | + }, { |
| 35 | + largest: 0x00, |
| 36 | + truncated: 0xff, |
| 37 | + size: 1, |
| 38 | + want: 0xff, |
| 39 | + }, { |
| 40 | + largest: 0xff, |
| 41 | + truncated: 0x01, |
| 42 | + size: 1, |
| 43 | + want: 0x101, |
| 44 | + }, { |
| 45 | + largest: 0x1000, |
| 46 | + truncated: 0xff, |
| 47 | + size: 1, |
| 48 | + want: 0xfff, |
| 49 | + }, { |
| 50 | + largest: 0xa82f30ea, |
| 51 | + truncated: 0x9b32, |
| 52 | + size: 2, |
| 53 | + want: 0xa82f9b32, |
| 54 | + }} { |
| 55 | + got := decodePacketNumber(test.largest, test.truncated, test.size) |
| 56 | + if got != test.want { |
| 57 | + t.Errorf("decodePacketNumber(largest=0x%x, truncated=0x%x, size=%v) = 0x%x, want 0x%x", test.largest, test.truncated, test.size, got, test.want) |
| 58 | + } |
| 59 | + } |
| 60 | +} |
| 61 | + |
| 62 | +func TestEncodePacketNumber(t *testing.T) { |
| 63 | + for _, test := range []struct { |
| 64 | + largestAcked packetNumber |
| 65 | + pnum packetNumber |
| 66 | + wantSize int |
| 67 | + }{{ |
| 68 | + largestAcked: -1, |
| 69 | + pnum: 0, |
| 70 | + wantSize: 1, |
| 71 | + }, { |
| 72 | + largestAcked: 1000, |
| 73 | + pnum: 1000 + 0x7f, |
| 74 | + wantSize: 1, |
| 75 | + }, { |
| 76 | + largestAcked: 1000, |
| 77 | + pnum: 1000 + 0x80, // 0x468 |
| 78 | + wantSize: 2, |
| 79 | + }, { |
| 80 | + largestAcked: 0x12345678, |
| 81 | + pnum: 0x12345678 + 0x7fff, // 0x305452663 |
| 82 | + wantSize: 2, |
| 83 | + }, { |
| 84 | + largestAcked: 0x12345678, |
| 85 | + pnum: 0x12345678 + 0x8000, |
| 86 | + wantSize: 3, |
| 87 | + }, { |
| 88 | + largestAcked: 0, |
| 89 | + pnum: 0x7fffff, |
| 90 | + wantSize: 3, |
| 91 | + }, { |
| 92 | + largestAcked: 0, |
| 93 | + pnum: 0x800000, |
| 94 | + wantSize: 4, |
| 95 | + }, { |
| 96 | + largestAcked: 0xabe8bc, |
| 97 | + pnum: 0xac5c02, |
| 98 | + wantSize: 2, |
| 99 | + }, { |
| 100 | + largestAcked: 0xabe8bc, |
| 101 | + pnum: 0xace8fe, |
| 102 | + wantSize: 3, |
| 103 | + }} { |
| 104 | + size := packetNumberLength(test.pnum, test.largestAcked) |
| 105 | + if got, want := size, test.wantSize; got != want { |
| 106 | + t.Errorf("packetNumberLength(num=%x, maxAck=%x) = %v, want %v", test.pnum, test.largestAcked, got, want) |
| 107 | + } |
| 108 | + var enc packetNumber |
| 109 | + switch size { |
| 110 | + case 1: |
| 111 | + enc = test.pnum & 0xff |
| 112 | + case 2: |
| 113 | + enc = test.pnum & 0xffff |
| 114 | + case 3: |
| 115 | + enc = test.pnum & 0xffffff |
| 116 | + case 4: |
| 117 | + enc = test.pnum & 0xffffffff |
| 118 | + } |
| 119 | + wantBytes := binary.BigEndian.AppendUint32(nil, uint32(enc))[4-size:] |
| 120 | + gotBytes := appendPacketNumber(nil, test.pnum, test.largestAcked) |
| 121 | + if !bytes.Equal(gotBytes, wantBytes) { |
| 122 | + t.Errorf("appendPacketNumber(num=%v, maxAck=%x) = {%x}, want {%x}", test.pnum, test.largestAcked, gotBytes, wantBytes) |
| 123 | + } |
| 124 | + gotNum := decodePacketNumber(test.largestAcked, enc, size) |
| 125 | + if got, want := gotNum, test.pnum; got != want { |
| 126 | + t.Errorf("packetNumberLength(num=%x, maxAck=%x) = %v, but decoded number=%x", test.pnum, test.largestAcked, size, got) |
| 127 | + } |
| 128 | + } |
| 129 | +} |
| 130 | + |
| 131 | +func FuzzPacketNumber(f *testing.F) { |
| 132 | + truncatedNumber := func(in []byte) packetNumber { |
| 133 | + var truncated packetNumber |
| 134 | + for _, b := range in { |
| 135 | + truncated = (truncated << 8) | packetNumber(b) |
| 136 | + } |
| 137 | + return truncated |
| 138 | + } |
| 139 | + f.Fuzz(func(t *testing.T, in []byte, largestAckedInt64 int64) { |
| 140 | + largestAcked := packetNumber(largestAckedInt64) |
| 141 | + if len(in) < 1 || len(in) > 4 || largestAcked < 0 || largestAcked > maxPacketNumber { |
| 142 | + return |
| 143 | + } |
| 144 | + truncatedIn := truncatedNumber(in) |
| 145 | + decoded := decodePacketNumber(largestAcked, truncatedIn, len(in)) |
| 146 | + |
| 147 | + // Check that the decoded packet number's least significant bits match the input. |
| 148 | + var mask packetNumber |
| 149 | + for i := 0; i < len(in); i++ { |
| 150 | + mask = (mask << 8) | 0xff |
| 151 | + } |
| 152 | + if truncatedIn != decoded&mask { |
| 153 | + t.Fatalf("decoding mismatch: input=%x largestAcked=%v decoded=0x%x", in, largestAcked, decoded) |
| 154 | + } |
| 155 | + |
| 156 | + // We don't support encoding packet numbers less than largestAcked (since packet numbers |
| 157 | + // never decrease), so skip the encoder tests if this would make us go backwards. |
| 158 | + if decoded < largestAcked { |
| 159 | + return |
| 160 | + } |
| 161 | + |
| 162 | + // We might encode this number using a different length than we received, |
| 163 | + // but the common portions should match. |
| 164 | + encoded := appendPacketNumber(nil, decoded, largestAcked) |
| 165 | + a, b := in, encoded |
| 166 | + if len(b) < len(a) { |
| 167 | + a, b = b, a |
| 168 | + } |
| 169 | + for len(a) < len(b) { |
| 170 | + b = b[1:] |
| 171 | + } |
| 172 | + if len(a) == 0 || !bytes.Equal(a, b) { |
| 173 | + t.Fatalf("encoding mismatch: input=%x largestAcked=%v decoded=%v reencoded=%x", in, largestAcked, decoded, encoded) |
| 174 | + } |
| 175 | + |
| 176 | + if g := decodePacketNumber(largestAcked, truncatedNumber(encoded), len(encoded)); g != decoded { |
| 177 | + t.Fatalf("packet encode/decode mismatch: pnum=%v largestAcked=%v encoded=%x got=%v", decoded, largestAcked, encoded, g) |
| 178 | + } |
| 179 | + if l := packetNumberLength(decoded, largestAcked); l != len(encoded) { |
| 180 | + t.Fatalf("packet number length mismatch: pnum=%v largestAcked=%v encoded=%x len=%v", decoded, largestAcked, encoded, l) |
| 181 | + } |
| 182 | + }) |
| 183 | +} |
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