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Date: Sun, 30 Jun 2013 23:30:32 -0700
From: Pravin B Shelar <pshelar@...ira.com>
To: netdev@...r.kernel.org
Cc: timo.teras@....fi, Pravin B Shelar <pshelar@...ira.com>
Subject: [PATCH net v2] ip_tunnels: Use skb-len to PMTU check.
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 c54419321455631079c7d (GRE: Refactor GRE tunneling code).
Reported-by: Timo Teras <timo.teras@....fi>
Signed-off-by: Pravin B Shelar <pshelar@...ira.com>
---
v1-v2:
- Fix pmtu set.
- This patch also restructures code which help couple of
improvements I have.
---
net/ipv4/ip_tunnel.c | 98 +++++++++++++++++++++++++++----------------------
1 files changed, 54 insertions(+), 44 deletions(-)
diff --git a/net/ipv4/ip_tunnel.c b/net/ipv4/ip_tunnel.c
index 7fa8f08..ae5b78c 100644
--- a/net/ipv4/ip_tunnel.c
+++ b/net/ipv4/ip_tunnel.c
@@ -486,6 +486,53 @@ drop:
}
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) {
+ 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)
{
@@ -499,7 +546,6 @@ void ip_tunnel_xmit(struct sk_buff *skb, struct net_device *dev,
struct net_device *tdev; /* Device to other host */
unsigned int max_headroom; /* The extra header space needed */
__be32 dst;
- int mtu;
inner_iph = (const struct iphdr *)skb_inner_network_header(skb);
@@ -579,50 +625,10 @@ void ip_tunnel_xmit(struct sk_buff *skb, struct net_device *dev,
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)) {
- icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED, htonl(mtu));
- 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;
- }
+ if (tnl_update_pmtu(dev, skb, rt, tnl_params->frag_off)) {
+ ip_rt_put(rt);
+ goto tx_error;
}
-#endif
if (tunnel->err_count > 0) {
if (time_before(jiffies,
@@ -667,6 +673,10 @@ void ip_tunnel_xmit(struct sk_buff *skb, struct net_device *dev,
iph = ip_hdr(skb);
inner_iph = (const struct iphdr *)skb_inner_network_header(skb);
+ df = tnl_params->frag_off;
+ if (skb->protocol == htons(ETH_P_IP))
+ df |= (inner_iph->frag_off&htons(IP_DF));
+
iph->version = 4;
iph->ihl = sizeof(struct iphdr) >> 2;
iph->frag_off = df;
--
1.7.1
--
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