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traceroute6: Properly calculate UDP checksum

Authored by on Apr 30 2021, 9:14 AM.



The revision D25604 capsicumize traceroute6. For UDP the send socket was changed from SOCK_DGRAM to SOCK_RAW and thus the UDP checksum need be calculated by application itself other than the kernel.

outpacket is filled with zeros by line 707, thus the first round the UDP checksum is correct. But subsequent rounds outudp->uh_sum will be left with garbage.

PR: 255507

Test Plan

host A <----> Router <----> host B

  1. traceroute6 hostB
  2. netstat -sp udp | grep 'bad checksum'

Diff Detail

rG FreeBSD src repository
Automatic diff as part of commit; lint not applicable.
Automatic diff as part of commit; unit tests not applicable.