Skip to content

Fix the dropping packets in the receive thread (actually this time)#870

Closed
phillip-stephens wants to merge 2 commits intomainfrom
phillip/drop-packets-tcp-syn-fix
Closed

Fix the dropping packets in the receive thread (actually this time)#870
phillip-stephens wants to merge 2 commits intomainfrom
phillip/drop-packets-tcp-syn-fix

Conversation

@phillip-stephens
Copy link
Contributor

@phillip-stephens phillip-stephens commented May 2, 2024 •
edited
Loading

Closes #868

I was re-testing this morning and realized even with #869 I was still seeing
May 01 23:04:18.146 [WARN] monitor: Dropped 58542 packets in the last second, (58554 total dropped (pcap: 58554 + iface: 0))

So reverting the PR that decreased the timeout on pcap wasn't the fix (should have caught that yesterday, I was too quick to assume and didn't validate sufficiently).
It seems the PR right after (#858 ), where we added TCP options parsing to the synscan_process_packet was the real culprit. Upon reverting that, everything works.

I will open an Issue to re-add TCP options parsing, might be some small tweaks we can do to that PR to speed it up so the callback can run fast enough to not bog down the receive thread.

Testing

Scan with current main (with pcap timeout reverted):

 0:00 0%; send: 93 1 p/s (5.91 Kp/s avg); recv: 0 0 p/s (0 p/s avg); drops: 0 p/s (0 p/s avg); hitrate: 0.00%
 0:01 2%; send: 3041530 3.04 Mp/s (2.99 Mp/s avg); recv: 34374 34.4 Kp/s (33.8 Kp/s avg); drops: 0 p/s (0 p/s avg); hitrate: 1.13%
 0:02 3%; send: 5720378 2.68 Mp/s (2.84 Mp/s avg); recv: 70396 36.0 Kp/s (34.9 Kp/s avg); drops: 0 p/s (0 p/s avg); hitrate: 1.23%
 0:03 5%; send: 8304058 2.58 Mp/s (2.75 Mp/s avg); recv: 104457 34.1 Kp/s (34.6 Kp/s avg); drops: 0 p/s (0 p/s avg); hitrate: 1.26%
 0:04 7%; send: 10790906 2.49 Mp/s (2.69 Mp/s avg); recv: 137604 33.1 Kp/s (34.3 Kp/s avg); drops: 0 p/s (0 p/s avg); hitrate: 1.28%
May 02 18:06:51.079 [WARN] monitor: Dropped 10847 packets in the last second, (10849 total dropped (pcap: 10849 + iface: 0))
 0:05 8% (56s left); send: 13204011 2.41 Mp/s (2.63 Mp/s avg); recv: 163004 25.4 Kp/s (32.5 Kp/s avg); drops: 10.8 Kp/s (2.16 Kp/s avg); hitrate: 1.23%
May 02 18:06:52.080 [WARN] monitor: Dropped 108676 packets in the last second, (119553 total dropped (pcap: 119553 + iface: 0))
 0:06 10% (55s left); send: 15609658 2.41 Mp/s (2.59 Mp/s avg); recv: 163004 0 p/s (27.1 Kp/s avg); drops: 109 Kp/s (19.9 Kp/s avg); hitrate: 1.04%
May 02 18:06:53.080 [WARN] monitor: Dropped 108048 packets in the last second, (227630 total dropped (pcap: 227630 + iface: 0))
 0:07 12% (54s left); send: 17982778 2.37 Mp/s (2.56 Mp/s avg); recv: 163004 0 p/s (23.2 Kp/s avg); drops: 108 Kp/s (32.4 Kp/s avg); hitrate: 0.91%
********May 02 18:06:54.080 [WARN] monitor: Dropped 109055 packets in the last second, (336708 total dropped (pcap: 336708 + iface: 0))
 0:08 13% (53s left); send: 20397849 2.41 Mp/s (2.54 Mp/s avg); recv: 163004 0 p/s (20.3 Kp/s avg); drops: 109 Kp/s (42.0 Kp/s avg); hitrate: 0.80%
********May 02 18:06:55.080 [WARN] monitor: Dropped 109878 packets in the last second, (446610 total dropped (pcap: 446610 + iface: 0))
 0:09 15% (52s left); send: 22852420 2.45 Mp/s (2.53 Mp/s avg); recv: 163004 0 p/s (18.1 Kp/s avg); drops: 110 Kp/s (49.5 Kp/s avg); hitrate: 0.71%
^C

~/zmap-dev on  main! ⌚ 18:06:55

Scan with this PR fix in

 0:00 0%; send: 63 1 p/s (1.76 Kp/s avg); recv: 0 0 p/s (0 p/s avg); drops: 0 p/s (0 p/s avg); hitrate: 0.00%
 0:01 2%; send: 2862010 2.86 Mp/s (2.76 Mp/s avg); recv: 32361 32.4 Kp/s (31.2 Kp/s avg); drops: 0 p/s (0 p/s avg); hitrate: 1.13%
 0:02 3%; send: 5505146 2.64 Mp/s (2.70 Mp/s avg); recv: 67326 35.0 Kp/s (33.1 Kp/s avg); drops: 0 p/s (0 p/s avg); hitrate: 1.22%
...
 1:00 98% (1s left); send: 152445504 done (2.54 Mp/s avg); recv: 1993556 28.2 Kp/s (33.2 Kp/s avg); drops: 0 p/s (0 p/s avg); hitrate: 1.31%
 1:01 100% (0s left); send: 152445504 done (2.54 Mp/s avg); recv: 1996225 2.67 Kp/s (32.7 Kp/s avg); drops: 0 p/s (0 p/s avg); hitrate: 1.31%
May 02 17:59:22.133 [INFO] zmap: completed

@phillip-stephens phillip-stephens requested a review from zakird May 2, 2024 18:09
@phillip-stephens phillip-stephens marked this pull request as ready for review May 2, 2024 18:09
@phillip-stephens phillip-stephens mentioned this pull request May 3, 2024
Merged
@phillip-stephens
Copy link
Contributor Author

phillip-stephens commented May 3, 2024

Closing because #871 will resolve this without loss of functionality

Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment

Reviewers

@zakird zakird Awaiting requested review from zakird

Assignees

@zakird zakird

Labels

None yet

Projects

None yet

Milestone

No milestone

Development

Successfully merging this pull request may close these issues.

monitor prints "Dropping X packets in the last second" repeatedly

2 participants

@phillip-stephens @zakird