From 21e6fea08a9e15f9158aebd3cba9c91c801057db Mon Sep 17 00:00:00 2001
From: bz <bz@FreeBSD.org>
Date: Fri, 25 May 2012 08:17:59 +0000
Subject: In case forwarding is turned on for a given address family, refuse to
 queue the packet for LRO and tell the driver to directly pass it on. This
 avoids re-assembly and later re-fragmentation problems when forwarding.

It's not the best solution but the simplest and most effective for
the moment.

Should have been done:	ages ago
Discussed with and by:	many
MFC after:		3 days
---
 sys/netinet/tcp_lro.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/sys/netinet/tcp_lro.c b/sys/netinet/tcp_lro.c
index e4c36ad..cd7d282 100644
--- a/sys/netinet/tcp_lro.c
+++ b/sys/netinet/tcp_lro.c
@@ -51,9 +51,12 @@ __FBSDID("$FreeBSD$");
 #include <netinet/in.h>
 #include <netinet/ip6.h>
 #include <netinet/ip.h>
+#include <netinet/ip_var.h>
 #include <netinet/tcp.h>
 #include <netinet/tcp_lro.h>
 
+#include <netinet6/ip6_var.h>
+
 #include <machine/in_cksum.h>
 
 #ifndef LRO_ENTRIES
@@ -369,6 +372,10 @@ tcp_lro_rx(struct lro_ctrl *lc, struct mbuf *m, uint32_t csum)
 	switch (eh_type) {
 #ifdef INET6
 	case ETHERTYPE_IPV6:
+		if (V_ip6_forwarding != 0) {
+			/* XXX-BZ stats but changing lro_ctrl is a problem. */
+			return (TCP_LRO_CANNOT);
+		}
 		l3hdr = ip6 = (struct ip6_hdr *)(eh + 1);
 		error = tcp_lro_rx_ipv6(lc, m, ip6, &th);
 		if (error != 0)
@@ -379,6 +386,10 @@ tcp_lro_rx(struct lro_ctrl *lc, struct mbuf *m, uint32_t csum)
 #endif
 #ifdef INET
 	case ETHERTYPE_IP:
+		if (V_ipforwarding != 0) {
+			/* XXX-BZ stats but changing lro_ctrl is a problem. */
+			return (TCP_LRO_CANNOT);
+		}
 		l3hdr = ip4 = (struct ip *)(eh + 1);
 		error = tcp_lro_rx_ipv4(lc, m, ip4, &th);
 		if (error != 0)
-- 
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