svn commit: r358311 - head/sys/netinet6

[Bjoern A. Zeeb]

Author: bz
Date: Tue Feb 25 15:03:41 2020
New Revision: 358311
URL: https://svnweb.freebsd.org/changeset/base/358311

Log:
  ip6_output: fix regression introduced in r358167 for ipv6 fragmentation
  
  When moving the calculations for the optlen into the if (opt) block
  which deals with possible extension headers I failed to initialise
  unfragpartlen to the ipv6 header length if there were no extension
  headers present.  Correct that mistake to make IPv6 fragment length
  calculcations work again.
  
  Reported by:	hselasky, kp
  OKed by:	hselasky, kp
  MFC after:	3 days
  X-MFC with:	r358167
  PR:		244393

Modified:
  head/sys/netinet6/ip6_output.c

Modified: head/sys/netinet6/ip6_output.c
==============================================================================
--- head/sys/netinet6/ip6_output.c	Tue Feb 25 12:56:06 2020	(r358310)
+++ head/sys/netinet6/ip6_output.c	Tue Feb 25 15:03:41 2020	(r358311)
@@ -497,7 +497,7 @@ ip6_output(struct mbuf *m0, struct ip6_pktopts *opt,
 	 */
 	bzero(&exthdrs, sizeof(exthdrs));
 	optlen = 0;
-	unfragpartlen = 0;
+	unfragpartlen = sizeof(struct ip6_hdr);
 	if (opt) {
 		/* Hop-by-Hop options header. */
 		MAKE_EXTHDR(opt->ip6po_hbh, &exthdrs.ip6e_hbh, optlen);
@@ -535,7 +535,7 @@ ip6_output(struct mbuf *m0, struct ip6_pktopts *opt,
 		/* Routing header. */
 		MAKE_EXTHDR(opt->ip6po_rthdr, &exthdrs.ip6e_rthdr, optlen);
 
-		unfragpartlen = optlen + sizeof(struct ip6_hdr);
+		unfragpartlen += optlen;
 
 		/*
 		 * NOTE: we don't add AH/ESP length here (done in