Commit 490ab081 authored by Pravin B Shelar's avatar Pravin B Shelar Committed by David S. Miller
Browse files

IP_GRE: Fix IP-Identification. 



GRE-GSO generates ip fragments with id 0,2,3,4... for every
GSO packet, which is not correct. Following patch fixes it
by setting ip-header id unique id of fragments are allowed.
As Eric Dumazet suggested it is optimized by using inner ip-header
whenever inner packet is ipv4.

Signed-off-by: default avatarPravin B Shelar <pshelar@nicira.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 2bedc2e6

include/net/ipip.h

+17 −0
Original line number Diff line number Diff line
@@ -71,4 +71,21 @@ static inline void iptunnel_xmit(struct sk_buff *skb, struct net_device *dev) 
	}

}



static inline void tunnel_ip_select_ident(struct sk_buff *skb,

					  const struct iphdr  *old_iph,

					  struct dst_entry *dst)

{

	struct iphdr *iph = ip_hdr(skb);



	if (iph->frag_off & htons(IP_DF))

		iph->id	= 0;

	else {

		/* Use inner packet iph-id if possible. */

		if (skb->protocol == htons(ETH_P_IP) && old_iph->id)

			iph->id	= old_iph->id;

		else

			__ip_select_ident(iph, dst,

					  (skb_shinfo(skb)->gso_segs ?: 1) - 1);

	}

}

#endif

net/ipv4/af_inet.c

+4 −2
Original line number Diff line number Diff line
@@ -1332,8 +1332,10 @@ static struct sk_buff *inet_gso_segment(struct sk_buff *skb, 
			if (skb->next != NULL)

				iph->frag_off |= htons(IP_MF);

			offset += (skb->len - skb->mac_len - iph->ihl * 4);

		} else

		} else  {

			if (!(iph->frag_off & htons(IP_DF)))

				iph->id = htons(id++);

		}

		iph->tot_len = htons(skb->len - skb->mac_len);

		iph->check = 0;

		iph->check = ip_fast_csum(skb_network_header(skb), iph->ihl);

net/ipv4/ip_gre.c

+2 −1
Original line number Diff line number Diff line
@@ -970,7 +970,8 @@ static netdev_tx_t ipgre_tunnel_xmit(struct sk_buff *skb, struct net_device *dev 
	iph->daddr		=	fl4.daddr;

	iph->saddr		=	fl4.saddr;

	iph->ttl		=	ttl;

	iph->id			=	0;



	tunnel_ip_select_ident(skb, old_iph, &rt->dst);



	if (ttl == 0) {

		if (skb->protocol == htons(ETH_P_IP))

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