Mirror/zeek
1
0
Fork 0
mirror of https://github.com/zeek/zeek.git synced 2025-10-15 21:18:20 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions 3

Switch one's complement checksum implementation

Browse source 
Borrows the `in_cksum` code from tcpdump, which borrowed from FreeBSD.
It handles unaligned data better and also unrolls the inner loop to
process 16 two-byte values at a time versus 2 one-byte values at a time
in the previous version.  Generally measured as ~1.5x faster in a
release build.  The new API should generally be more amenable to any
future optimization explorations since all relevant data blocks are
available within a single call rather than spread across multiple.
This commit is contained in:
Jon Siwek 2020-09-24 08:47:50 -07:00
parent 8feca7291b
commit d070709c57
12 changed files with 283 additions and 74 deletions
Download patch file Download diff file Expand all files Collapse all files

2
src/Sessions.cc
View file

@ -269,7 +269,7 @@ void NetSessions::DoNextPacket(double t, const Packet* pkt, const IP_Hdr* ip_hdr
return;
if ( ! pkt->l2_checksummed && ! zeek::detail::ignore_checksums && ip4 &&
ones_complement_checksum((void*) ip4, ip_hdr_len, 0) != 0xffff )
detail::in_cksum(reinterpret_cast<const uint8_t*>(ip4), ip_hdr_len) != 0xffff )
{
Weird("bad_IP_checksum", pkt, encapsulation);
return;