Branch: refs/heads/misc-bugfixes Home: https://github.com/kronosnet/kronosnet Commit: c15bae3f36cc742cf53d82b4a91db6c57435fba6 https://github.com/kronosnet/kronosnet/commit/c15bae3f36cc742cf53d82b4a91db6... Author: Fabio M. Di Nitto fdinitto@redhat.com Date: 2026-05-21 (Thu, 21 May 2026)
Changed paths: M libknet/tests/Makefile.am A libknet/tests/int_decompress_bufsize.c M libknet/tests/test-common.c M libknet/tests/test-common.h M libknet/threads_rx.c
Log Message: ----------- libknet: add decompression buffer size validation
Add validation to reject packets where decompressed size exceeds KNET_DATABUFSIZE, preventing buffer overflows in decompression.
Add int_decompress_bufsize test that verifies packets with oversized decompressed payloads are properly rejected with appropriate logging.
Signed-off-by: Fabio M. Di Nitto fabbione@kronosnet.org Co-Authored-By: Claude Sonnet 4.5 noreply@anthropic.com
Commit: 19879cd469b77cc8d77cc552d954a8a17840ec16 https://github.com/kronosnet/kronosnet/commit/19879cd469b77cc8d77cc552d954a8... Author: Fabio M. Di Nitto fdinitto@redhat.com Date: 2026-05-21 (Thu, 21 May 2026)
Changed paths: M libknet/host.c
Log Message: ----------- libknet: fix defragmentation buffer reclamation using wrong sequence number
The defragmentation buffer reclamation was using the old received sequence number (dst_seq_num) instead of the current packet's sequence number to calculate the valid buffer window.
This caused buffers to be reclaimed based on stale sequence information, potentially freeing buffers that should still be valid or keeping buffers that should be reclaimed.
Fixed by passing seq_num (current packet) instead of dst_seq_num (last received) to _reclaim_old_defrag_bufs().
Signed-off-by: Fabio M. Di Nitto fdinitto@redhat.com Co-Authored-By: Claude Sonnet 4.5 noreply@anthropic.com
Commit: a9033dd020d74ccd6830caf80fcecf536fe114f9 https://github.com/kronosnet/kronosnet/commit/a9033dd020d74ccd6830caf80fcecf... Author: Fabio M. Di Nitto fdinitto@redhat.com Date: 2026-05-21 (Thu, 21 May 2026)
Changed paths: M libknet/host.c
Log Message: ----------- libknet: fix sequence number wraparound calculation in defragmentation
The distance calculation between sequence numbers was incorrect when wraparound occurred. The formula was backwards: it subtracted in the wrong direction and didn't account for the +1 needed for modular arithmetic.
This caused incorrect buffer reclamation decisions near the SEQ_MAX boundary.
Practical examples (SEQ_MAX = 65535):
Example 1 - Normal case (no wraparound): Last packet: dst_seq_num = 1000 New packet: seq_num = 1005 Expected distance: 5
BEFORE (wrong): seq_dist = dst_seq_num - seq_num = 1000 - 1005 = -5 (negative!)
AFTER (correct): seq_dist = seq_num - dst_seq_num = 1005 - 1000 = 5
Example 2 - Wraparound case: Last packet: dst_seq_num = 65534 New packet: seq_num = 3 (wrapped around) Expected distance: 5 (65534→65535→0→1→2→3)
BEFORE (wrong): seq_dist = (SEQ_MAX - seq_num) + dst_seq_num seq_dist = (65535 - 3) + 65534 = 131066 (huge wrong number!)
AFTER (correct): seq_dist = (SEQ_MAX - dst_seq_num) + seq_num + 1 seq_dist = (65535 - 65534) + 3 + 1 = 5
The +1 accounts for the transition from 65535→0 being one step, not zero.
Verification that circular buffer cleaning is not broken:
The seq_dist value is used to determine whether the new packet is: a) Within the circular buffer window (seq_dist < KNET_CBUFFER_SIZE) b) Far enough to require full buffer clear (seq_dist > threshold) c) Should trigger incremental cleaning (fall through case)
Test case 1 - Normal sequential packet: dst_seq_num = 1000, seq_num = 1005, expected distance = 5
BEFORE: seq_dist = -5 (unsigned overflow ~65530) → Incorrectly clears entire buffer for normal sequential packets!
AFTER: seq_dist = 5 → Correctly identifies packet as within buffer window, no clearing needed
Test case 2 - Wraparound (close distance): dst_seq_num = 65534, seq_num = 3, expected distance = 5
BEFORE: seq_dist = 131066 → Falls through to circular buffer cleaning code incorrectly
AFTER: seq_dist = 5 → Correctly identifies packet as within buffer window
Test case 3 - Large jump requiring buffer clear: dst_seq_num = 1000, seq_num = 50000, expected distance = 49000
BEFORE: seq_dist = -49000 (unsigned ~16536) → Clears buffer (correct by accident)
AFTER: seq_dist = 49000 → Clears buffer (correct by design)
The circular buffer cleaning code (lines 673-684) uses seq_num and dst_seq_num directly via modulo operations to find buffer positions. It does not use seq_dist for position calculations, only for the threshold check to determine whether to run. The fix corrects the threshold logic without affecting the position calculations.
Signed-off-by: Fabio M. Di Nitto fdinitto@redhat.com Co-Authored-By: Claude Sonnet 4.5 noreply@anthropic.com
Commit: f55a1bfdbc0b52b473ca00e7d9eee52094ddb31d https://github.com/kronosnet/kronosnet/commit/f55a1bfdbc0b52b473ca00e7d9eee5... Author: Fabio M. Di Nitto fdinitto@redhat.com Date: 2026-05-21 (Thu, 21 May 2026)
Changed paths: M libknet/tests/Makefile.am A libknet/tests/int_seq_wraparound_stress.c
Log Message: ----------- [tests] add comprehensive sequence number wraparound stress test
Add new int_seq_wraparound_stress test that exercises sequence number wraparound and defragmentation buffer management with realistic packet loss scenarios.
The test uses knet_recv() to properly receive packets one at a time through the socketpair interface, verifying correct behavior across 8 comprehensive test scenarios:
1. Normal sequential packets with occasional loss 2. Wraparound boundary (65535->0) with packet loss 3. Large sequence jumps (>KNET_CBUFFER_SIZE) triggering buffer clearing 4. Out-of-order fragment delivery within same sequence number 5. Out-of-order complete packet delivery (different sequence numbers) 6. Extreme packet loss beyond receive window 7. Wraparound with extreme loss (>KNET_CBUFFER_SIZE gap) 8. Wraparound stress with multiple cycles and duplicate detection
Signed-off-by: Fabio M. Di Nitto fabbione@kronosnet.org Co-Authored-By: Claude Sonnet 4.5 noreply@anthropic.com
Compare: https://github.com/kronosnet/kronosnet/compare/18b371c7a23f...f55a1bfdbc0b
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