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[03/11] vti6: fix ipv4 pmtu check to honor ip header df

Message ID 20210331081847.3547641-4-steffen.klassert@secunet.com (mailing list archive)
State Accepted
Commit 4c38255892c06b9de2fb3bf6aea63f4ebdff3d11
Delegated to: Netdev Maintainers
Headers show
Series [01/11] xfrm: interface: fix ipv4 pmtu check to honor ip header df | expand

Checks

Context Check Description
netdev/tree_selection success Guessing tree name failed - patch did not apply

Commit Message

Steffen Klassert March 31, 2021, 8:18 a.m. UTC 
From: Eyal Birger <eyal.birger@gmail.com>

Frag needed should only be sent if the header enables DF.

This fix allows IPv4 packets larger than MTU to pass the vti6 interface
and be fragmented after encapsulation, aligning behavior with
non-vti6 xfrm.

Fixes: ccd740cbc6e0 ("vti6: Add pmtu handling to vti6_xmit.")
Signed-off-by: Eyal Birger <eyal.birger@gmail.com>
Reviewed-by: Sabrina Dubroca <sd@queasysnail.net>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
---
 net/ipv6/ip6_vti.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)
diff mbox series

Patch

diff --git a/net/ipv6/ip6_vti.c b/net/ipv6/ip6_vti.c
index 0225fd694192..2f0be5ac021c 100644
--- a/net/ipv6/ip6_vti.c
+++ b/net/ipv6/ip6_vti.c
@@ -494,7 +494,7 @@  vti6_xmit(struct sk_buff *skb, struct net_device *dev, struct flowi *fl)
 	}
 
 	if (dst->flags & DST_XFRM_QUEUE)
-		goto queued;
+		goto xmit;
 
 	x = dst->xfrm;
 	if (!vti6_state_check(x, &t->parms.raddr, &t->parms.laddr))
@@ -523,6 +523,8 @@  vti6_xmit(struct sk_buff *skb, struct net_device *dev, struct flowi *fl)
 
 			icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
 		} else {
+			if (!(ip_hdr(skb)->frag_off & htons(IP_DF)))
+				goto xmit;
 			icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED,
 				  htonl(mtu));
 		}
@@ -531,7 +533,7 @@  vti6_xmit(struct sk_buff *skb, struct net_device *dev, struct flowi *fl)
 		goto tx_err_dst_release;
 	}
 
-queued:
+xmit:
 	skb_scrub_packet(skb, !net_eq(t->net, dev_net(dev)));
 	skb_dst_set(skb, dst);
 	skb->dev = skb_dst(skb)->dev;