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Merged
gasbytes merged 1 commit into from
Mar 2, 2026
Merged

Use correct comparison in SACK reordering to avoid wrapping errors #55

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34 changes: 34 additions & 0 deletions src/test/unit/unit.c
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Original file line number Diff line number Diff line change
Expand Up @@ -10236,6 +10236,21 @@ START_TEST(test_tcp_sort_sack_blocks_swaps_out_of_order)
}
END_TEST

START_TEST(test_tcp_sort_sack_blocks_wrap_order)
{
struct tcp_sack_block blocks[2];

blocks[0].left = 0x00000010U;
blocks[0].right = 0x00000020U;
blocks[1].left = 0xFFFFFFF0U;
blocks[1].right = 0xFFFFFFF8U;

tcp_sort_sack_blocks(blocks, 2);
ck_assert_uint_eq(blocks[0].left, 0xFFFFFFF0U);
ck_assert_uint_eq(blocks[1].left, 0x00000010U);
}
END_TEST

START_TEST(test_tcp_merge_sack_blocks_adjacent_and_disjoint)
{
struct tcp_sack_block blocks[3];
Expand All @@ -10254,6 +10269,23 @@ START_TEST(test_tcp_merge_sack_blocks_adjacent_and_disjoint)
}
END_TEST

START_TEST(test_tcp_merge_sack_blocks_wrap_order)
{
struct tcp_sack_block blocks[2];
uint8_t merged;

blocks[0].left = 0x00000010U;
blocks[0].right = 0x00000020U;
blocks[1].left = 0xFFFFFFF0U;
blocks[1].right = 0xFFFFFFF8U;

merged = tcp_merge_sack_blocks(blocks, 2);
ck_assert_uint_eq(merged, 2U);
ck_assert_uint_eq(blocks[0].left, 0xFFFFFFF0U);
ck_assert_uint_eq(blocks[1].left, 0x00000010U);
}
END_TEST

START_TEST(test_tcp_recv_tracks_holes_and_sack_blocks)
{
struct wolfIP s;
Expand Down Expand Up @@ -17299,7 +17331,9 @@ Suite *wolf_suite(void)
tcase_add_test(tc_utils, test_tcp_build_ack_options_does_not_write_past_returned_len);
tcase_add_test(tc_utils, test_tcp_build_ack_options_omits_ts_when_not_negotiated);
tcase_add_test(tc_utils, test_tcp_sort_sack_blocks_swaps_out_of_order);
tcase_add_test(tc_utils, test_tcp_sort_sack_blocks_wrap_order);
tcase_add_test(tc_utils, test_tcp_merge_sack_blocks_adjacent_and_disjoint);
tcase_add_test(tc_utils, test_tcp_merge_sack_blocks_wrap_order);
tcase_add_test(tc_utils, test_tcp_recv_tracks_holes_and_sack_blocks);
tcase_add_test(tc_utils, test_tcp_rebuild_rx_sack_right_edge_wraps);
tcase_add_test(tc_utils, test_tcp_consume_ooo_wrap_trim_and_promote);
Expand Down
6 changes: 3 additions & 3 deletions src/wolfip.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1879,7 +1879,7 @@ static void tcp_sort_sack_blocks(struct tcp_sack_block *blocks, uint8_t count)
/* Small fixed-size sort (n <= 4) to normalize interval order before merge. */
for (i = 0; i < count; i++) {
for (j = (uint8_t)(i + 1); j < count; j++) {
if (blocks[j].left < blocks[i].left) {
if (tcp_seq_lt(blocks[j].left, blocks[i].left)) {
struct tcp_sack_block tmp = blocks[i];
blocks[i] = blocks[j];
blocks[j] = tmp;
Expand All @@ -1899,8 +1899,8 @@ static uint8_t tcp_merge_sack_blocks(struct tcp_sack_block *blocks, uint8_t coun
* - gap: keep as separate ranges */
tcp_sort_sack_blocks(blocks, count);
for (i = 1; i < count; i++) {
if (blocks[i].left < blocks[out].right) {
if (blocks[i].right > blocks[out].right)
if (tcp_seq_lt(blocks[i].left, blocks[out].right)) {
if (!tcp_seq_leq(blocks[i].right, blocks[out].right))
blocks[out].right = blocks[i].right;
} else if (blocks[i].left == blocks[out].right) {
blocks[out].right = blocks[i].right;
Expand Down