Module Name:    src
Committed By:   christos
Date:           Wed Jun 26 15:31:17 UTC 2019

Modified Files:
        src/sys/external/bsd/ipf/netinet: fil.c

Log Message:
Conform to RFC 3128 by dropping TCP fragments with offset = 1.
In addition to dropping these fragments, add a DTrace probe to allow
for more detailed monitoring and diagnosis if required.
>From FreeBSD r349399, reported vy Cy Schubert


To generate a diff of this commit:
cvs rdiff -u -r1.27 -r1.28 src/sys/external/bsd/ipf/netinet/fil.c

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

Modified files:

Index: src/sys/external/bsd/ipf/netinet/fil.c
diff -u src/sys/external/bsd/ipf/netinet/fil.c:1.27 src/sys/external/bsd/ipf/netinet/fil.c:1.28
--- src/sys/external/bsd/ipf/netinet/fil.c:1.27	Wed Jun 26 11:26:57 2019
+++ src/sys/external/bsd/ipf/netinet/fil.c	Wed Jun 26 11:31:17 2019
@@ -1,4 +1,4 @@
-/*	$NetBSD: fil.c,v 1.27 2019/06/26 15:26:57 christos Exp $	*/
+/*	$NetBSD: fil.c,v 1.28 2019/06/26 15:31:17 christos Exp $	*/
 
 /*
  * Copyright (C) 2012 by Darren Reed.
@@ -141,7 +141,7 @@ extern struct timeout ipf_slowtimer_ch;
 #if !defined(lint)
 #if defined(__NetBSD__)
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: fil.c,v 1.27 2019/06/26 15:26:57 christos Exp $");
+__KERNEL_RCSID(0, "$NetBSD: fil.c,v 1.28 2019/06/26 15:31:17 christos Exp $");
 #else
 static const char sccsid[] = "@(#)fil.c	1.36 6/5/96 (C) 1993-2000 Darren Reed";
 static const char rcsid[] = "@(#)Id: fil.c,v 1.1.1.2 2012/07/22 13:45:07 darrenr Exp $";
@@ -1721,6 +1721,10 @@ ipf_pr_ipv4hdr(fr_info_t *fin)
 	 * calculate the byte offset that it represents.
 	 */
 	off &= IP_MF|IP_OFFMASK;
+	if (off == 1 && p == IPPROTO_TCP) {
+		fin->fin_flx |= FI_SHORT;	/* RFC 3128 */
+		DT1(ipf_fi_tcp_frag_off_1, fr_info_t *, fin);
+	}
 	if (off != 0) {
 		int morefrag = off & IP_MF;
 

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