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ip_tunnels: Use skb-len to PMTU check.

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In path mtu check, ip header total length works for gre device
but not for gre-tap device.  Use skb len which is consistent
for all tunneling types.  This is old bug in gre.
This also fixes mtu calculation bug introduced by
commit c544193214 (GRE: Refactor GRE tunneling code).

Reported-by: Timo Teras <timo.teras@iki.fi>
Signed-off-by: Pravin B Shelar <pshelar@nicira.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Pravin B Shelar 2013-07-02 10:57:33 -07:00 committed by David S. Miller
parent 784771e74b
commit 23a3647bc4
1 changed files with 55 additions and 44 deletions
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99
net/ipv4/ip_tunnel.c
View File

@ -472,6 +472,54 @@ int ip_tunnel_rcv(struct ip_tunnel *tunnel, struct sk_buff *skb,
}
EXPORT_SYMBOL_GPL(ip_tunnel_rcv);
static int tnl_update_pmtu(struct net_device *dev, struct sk_buff *skb,
struct rtable *rt, __be16 df)
{
struct ip_tunnel *tunnel = netdev_priv(dev);
int pkt_size = skb->len - tunnel->hlen;
int mtu;
if (df)
mtu = dst_mtu(&rt->dst) - dev->hard_header_len
- sizeof(struct iphdr) - tunnel->hlen;
else
mtu = skb_dst(skb) ? dst_mtu(skb_dst(skb)) : dev->mtu;
if (skb_dst(skb))
skb_dst(skb)->ops->update_pmtu(skb_dst(skb), NULL, skb, mtu);
if (skb->protocol == htons(ETH_P_IP)) {
if (!skb_is_gso(skb) &&
(df & htons(IP_DF)) && mtu < pkt_size) {
memset(IPCB(skb), 0, sizeof(*IPCB(skb)));
icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED, htonl(mtu));
return -E2BIG;
}
}
#if IS_ENABLED(CONFIG_IPV6)
else if (skb->protocol == htons(ETH_P_IPV6)) {
struct rt6_info *rt6 = (struct rt6_info *)skb_dst(skb);
if (rt6 && mtu < dst_mtu(skb_dst(skb)) &&
mtu >= IPV6_MIN_MTU) {
if ((tunnel->parms.iph.daddr &&
!ipv4_is_multicast(tunnel->parms.iph.daddr)) ||
rt6->rt6i_dst.plen == 128) {
rt6->rt6i_flags |= RTF_MODIFIED;
dst_metric_set(skb_dst(skb), RTAX_MTU, mtu);
}
}
if (!skb_is_gso(skb) && mtu >= IPV6_MIN_MTU &&
mtu < pkt_size) {
icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
return -E2BIG;
}
}
#endif
return 0;
}
void ip_tunnel_xmit(struct sk_buff *skb, struct net_device *dev,
const struct iphdr *tnl_params, const u8 protocol)
{
@ -483,7 +531,6 @@ void ip_tunnel_xmit(struct sk_buff *skb, struct net_device *dev,
struct rtable *rt; /* Route to the other host */
unsigned int max_headroom; /* The extra header space needed */
__be32 dst;
int mtu;
int err;
inner_iph = (const struct iphdr *)skb_inner_network_header(skb);
@ -560,51 +607,11 @@ void ip_tunnel_xmit(struct sk_buff *skb, struct net_device *dev,
dev->stats.collisions++;
goto tx_error;
}
df = tnl_params->frag_off;
if (df)
mtu = dst_mtu(&rt->dst) - dev->hard_header_len
- sizeof(struct iphdr);
else
mtu = skb_dst(skb) ? dst_mtu(skb_dst(skb)) : dev->mtu;
if (skb_dst(skb))
skb_dst(skb)->ops->update_pmtu(skb_dst(skb), NULL, skb, mtu);
if (skb->protocol == htons(ETH_P_IP)) {
df |= (inner_iph->frag_off&htons(IP_DF));
if (!skb_is_gso(skb) &&
(inner_iph->frag_off&htons(IP_DF)) &&
mtu < ntohs(inner_iph->tot_len)) {
memset(IPCB(skb), 0, sizeof(*IPCB(skb)));
icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED, htonl(mtu));
ip_rt_put(rt);
goto tx_error;
}
if (tnl_update_pmtu(dev, skb, rt, tnl_params->frag_off)) {
ip_rt_put(rt);
goto tx_error;
}
#if IS_ENABLED(CONFIG_IPV6)
else if (skb->protocol == htons(ETH_P_IPV6)) {
struct rt6_info *rt6 = (struct rt6_info *)skb_dst(skb);
if (rt6 && mtu < dst_mtu(skb_dst(skb)) &&
mtu >= IPV6_MIN_MTU) {
if ((tunnel->parms.iph.daddr &&
!ipv4_is_multicast(tunnel->parms.iph.daddr)) ||
rt6->rt6i_dst.plen == 128) {
rt6->rt6i_flags |= RTF_MODIFIED;
dst_metric_set(skb_dst(skb), RTAX_MTU, mtu);
}
}
if (!skb_is_gso(skb) && mtu >= IPV6_MIN_MTU &&
mtu < skb->len) {
icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
ip_rt_put(rt);
goto tx_error;
}
}
#endif
if (tunnel->net != dev_net(dev))
skb_scrub_packet(skb);
@ -631,6 +638,10 @@ void ip_tunnel_xmit(struct sk_buff *skb, struct net_device *dev,
ttl = ip4_dst_hoplimit(&rt->dst);
}
df = tnl_params->frag_off;
if (skb->protocol == htons(ETH_P_IP))
df |= (inner_iph->frag_off&htons(IP_DF));
max_headroom = LL_RESERVED_SPACE(rt->dst.dev) + sizeof(struct iphdr)
+ rt->dst.header_len;
if (max_headroom > dev->needed_headroom) {