CVS commit: src/sys/netinet

["Jaromir Dolecek" <jdolecek%netbsd.org@localhost>]

Module Name:    src
Committed By:   jdolecek
Date:           Fri Mar 27 16:34:58 UTC 2020

Modified Files:
        src/sys/netinet: in_offload.c

Log Message:
fix in4_cksum() panic "in4_cksum: mbuf 14 too short for IP header 20"
triggered by bridge_output() when passing packet originally for
interface supporting hw csum offload to destination interface
not supporting it

problem happens because bridge_output() is called after ether_output()
M_PREPEND() the ether_header into the mbuf chain, if there is not
enough space on the first mbuf of the chain, it ends up prepending
a new short mbuf with just ether_header

triggered by running UDP (IPv4) 'netio -u' benchmark with packet size 2 KB

XXX seems in6_undefer_cksum() should have similar fix, however I was
XXX not able to trigger the problem there


To generate a diff of this commit:
cvs rdiff -u -r1.13 -r1.14 src/sys/netinet/in_offload.c

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.