svn commit: r327052 - head/sys/net

[Stephen Hurd]

Author: shurd
Date: Thu Dec 21 01:22:36 2017
New Revision: 327052
URL: https://svnweb.freebsd.org/changeset/base/327052

Log:
  Don't call tcp_lro_rx() unless hardware verified TCP/UDP csum
  
  It seems that tcp_lro_rx() doesn't verify TCP checksums, so
  if there are bad checksums in the packets caused by invalid data, the
  invalid data will pass through without errors.
  
  This was noticed with the igb driver and a specific internet host:
  fetch http://www.mpfr.org/mpfr-current/mpfr-3.1.6.tar.xz -o test.bin && sha256 test.bin
  Would result in a different value sometimes.
  
  This ends up making LRO require RXCSUM to be enabled, and RXCSUM to
  support TCP and UDP checksums.
  
  PR:		224346
  Reported by:	gjb
  Reviewed by:	sbruno
  Sponsored by:	Limelight Networks
  Differential Revision:	https://reviews.freebsd.org/D13561

Modified:
  head/sys/net/iflib.c

Modified: head/sys/net/iflib.c
==============================================================================
--- head/sys/net/iflib.c	Thu Dec 21 00:35:14 2017	(r327051)
+++ head/sys/net/iflib.c	Thu Dec 21 01:22:36 2017	(r327052)
@@ -2632,8 +2632,11 @@ iflib_rxeof(iflib_rxq_t rxq, qidx_t budget)
 					mt = mf = NULL;
 				}
 			}
-			if (lro_possible && tcp_lro_rx(&rxq->ifr_lc, m, 0) == 0)
+			if ((m->m_pkthdr.csum_flags & (CSUM_L4_CALC|CSUM_L4_VALID)) ==
+			    (CSUM_L4_CALC|CSUM_L4_VALID)) {
+				if (lro_possible && tcp_lro_rx(&rxq->ifr_lc, m, 0) == 0)
 				continue;
+			}
 		}
 #endif
 		if (lro_possible) {