Bug 64 - Traceroute will not operate through passt/pasta
Summary: Traceroute will not operate through passt/pasta
Status: CONFIRMED
Alias: None
Product: passt
Classification: Unclassified
Component: UDP (show other bugs)
Version: unspecified
Hardware: All Linux
: Low enhancement
Assignee: nobody
URL:
Depends on:
Blocks:
 
Reported: 2023-07-04 03:27 UTC by David Gibson
Modified: 2023-07-04 03:27 UTC (History)
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Description David Gibson 2023-07-04 03:27:01 UTC 
Traceroute or similar tools (mtr, tracepath) can't be used through passt, because we don't propagate IP level TTL values to our outgoing sockets.

I believe it would be possible to do this by:
  * Using the IP_TTL socket option to propagate the TTL from UDP packets received on the tap interface to the outgoing UDP sockets
  * Using IP_RECVERR on outward facing UDP sockets to detect time exceeded erorrs and propagate them to the guest with synthesized ICMP packets.
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