fix(parser): resolve BAD CHK for BW frames caused by SESSION_RESET bytes #4

2026-04-20T17:01:20-04:00

serversdown commented

2026-04-20 17:01:20 -04:00

SESSION_RESET (41 03) is sent before each POLL frame to wake monitoring
units. The ETX lookahead in parse_bw only checked for ACK+STX directly
after ETX, so when 41 03 followed a frame's ETX, the check failed and the
ETX was swallowed into the body as a payload byte — giving a 19-byte body
instead of 17 for POLL frames and failing checksum validation.

Fix: scan past any SESSION_RESET (41 03) sequences when looking for the
next frame start, so the real ACK+STX boundary is found correctly.

Also adds SUM8 checksum validation to parse_s3, which previously left
checksum_valid=None for all S3 frames.

https://claude.ai/code/session_014NczSHUz9uTzCAf4cVASTJ

SESSION_RESET (41 03) is sent before each POLL frame to wake monitoring units. The ETX lookahead in parse_bw only checked for ACK+STX directly after ETX, so when 41 03 followed a frame's ETX, the check failed and the ETX was swallowed into the body as a payload byte — giving a 19-byte body instead of 17 for POLL frames and failing checksum validation. Fix: scan past any SESSION_RESET (41 03) sequences when looking for the next frame start, so the real ACK+STX boundary is found correctly. Also adds SUM8 checksum validation to parse_s3, which previously left checksum_valid=None for all S3 frames. https://claude.ai/code/session_014NczSHUz9uTzCAf4cVASTJ

serversdown added 1 commit 2026-04-20 17:01:21 -04:00

fix(parser): resolve BAD CHK for BW frames caused by SESSION_RESET bytes 34df9ec5fa

SESSION_RESET (41 03) is sent before each POLL frame to wake monitoring
units. The ETX lookahead in parse_bw only checked for ACK+STX directly
after ETX, so when 41 03 followed a frame's ETX, the check failed and the
ETX was swallowed into the body as a payload byte — giving a 19-byte body
instead of 17 for POLL frames and failing checksum validation.

Fix: scan past any SESSION_RESET (41 03) sequences when looking for the
next frame start, so the real ACK+STX boundary is found correctly.

Also adds SUM8 checksum validation to parse_s3, which previously left
checksum_valid=None for all S3 frames.

https://claude.ai/code/session_014NczSHUz9uTzCAf4cVASTJ

serversdown merged commit a7aec31915 into protocol-exp

2026-04-20 17:01:35 -04:00

serversdown referenced this issue from a commit

2026-04-20 17:01:37 -04:00

Merge pull request 'fix(parser): resolve BAD CHK for BW frames caused by SESSION_RESET bytes' (#4) from seismo-lab into protocol-exp

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Reference: serversdown/seismo-relay#4