[PATCH v7 net-next 05/13] iptunnel: Generalize tunnel update pmtu

[Tom Herbert]

Add __iptunnel_update_pmtu exported function which does not take
an iptunnel argument but instead includes the fields from the
iptunnel structure as arguments which are needed in the function.

iptunnel_update_pmtu was modified to call __iptunnel_update_pmtu.

Signed-off-by: Tom Herbert <t...@quantonium.net>
---
 include/net/ip_tunnels.h |  4 ++++
 net/ipv4/ip_tunnel.c     | 30 ++++++++++++++++++++----------
 2 files changed, 24 insertions(+), 10 deletions(-)

diff --git a/include/net/ip_tunnels.h b/include/net/ip_tunnels.h
index 2b05ae24f4f6..be675836d35a 100644
--- a/include/net/ip_tunnels.h
+++ b/include/net/ip_tunnels.h
@@ -317,6 +317,10 @@ static inline struct rtable *ip_tunnel_get_route(struct 
net_device *dev,
                                     dst_cache, use_cache);
 }
 
+int __iptunnel_update_pmtu(struct net_device *dev, struct sk_buff *skb,
+                          struct dst_entry *dst, __be16 df,
+                          const struct iphdr *inner_iph, int hlen, u32 daddr);
+
 struct ip_tunnel_encap_ops {
        size_t (*encap_hlen)(struct ip_tunnel_encap *e);
        int (*build_header)(struct sk_buff *skb, struct ip_tunnel_encap *e,
diff --git a/net/ipv4/ip_tunnel.c b/net/ipv4/ip_tunnel.c
index c97525d8dff9..0ee84ca76e0f 100644
--- a/net/ipv4/ip_tunnel.c
+++ b/net/ipv4/ip_tunnel.c
@@ -506,17 +506,16 @@ int ip_tunnel_encap_setup(struct ip_tunnel *t,
 }
 EXPORT_SYMBOL_GPL(ip_tunnel_encap_setup);
 
-static int tnl_update_pmtu(struct net_device *dev, struct sk_buff *skb,
-                           struct rtable *rt, __be16 df,
-                           const struct iphdr *inner_iph)
+int __iptunnel_update_pmtu(struct net_device *dev, struct sk_buff *skb,
+                          struct dst_entry *dst, __be16 df,
+                          const struct iphdr *inner_iph, int hlen, u32 daddr)
 {
-       struct ip_tunnel *tunnel = netdev_priv(dev);
-       int pkt_size = skb->len - tunnel->hlen - dev->hard_header_len;
+       int pkt_size = skb->len - hlen - dev->hard_header_len;
        int mtu;
 
        if (df)
-               mtu = dst_mtu(&rt->dst) - dev->hard_header_len
-                                       - sizeof(struct iphdr) - tunnel->hlen;
+               mtu = dst_mtu(dst) - dev->hard_header_len
+                                  - sizeof(struct iphdr) - hlen;
        else
                mtu = skb_dst(skb) ? dst_mtu(skb_dst(skb)) : dev->mtu;
 
@@ -538,8 +537,7 @@ static int tnl_update_pmtu(struct net_device *dev, struct 
sk_buff *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)) ||
+                       if ((daddr && !ipv4_is_multicast(daddr)) ||
                            rt6->rt6i_dst.plen == 128) {
                                rt6->rt6i_flags |= RTF_MODIFIED;
                                dst_metric_set(skb_dst(skb), RTAX_MTU, mtu);
@@ -555,6 +553,17 @@ static int tnl_update_pmtu(struct net_device *dev, struct 
sk_buff *skb,
 #endif
        return 0;
 }
+EXPORT_SYMBOL(__iptunnel_update_pmtu);
+
+static int iptunnel_update_pmtu(struct net_device *dev, struct sk_buff *skb,
+                               struct rtable *rt, __be16 df,
+                               const struct iphdr *inner_iph)
+{
+       struct ip_tunnel *tunnel = netdev_priv(dev);
+
+       return __iptunnel_update_pmtu(dev, skb, &rt->dst, df, inner_iph,
+                                     tunnel->hlen, tunnel->parms.iph.daddr);
+}
 
 void ip_md_tunnel_xmit(struct sk_buff *skb, struct net_device *dev, u8 proto)
 {
@@ -739,7 +748,8 @@ void ip_tunnel_xmit(struct sk_buff *skb, struct net_device 
*dev,
                goto tx_error;
        }
 
-       if (tnl_update_pmtu(dev, skb, rt, tnl_params->frag_off, inner_iph)) {
+       if (iptunnel_update_pmtu(dev, skb, rt, tnl_params->frag_off,
+                                inner_iph)) {
                ip_rt_put(rt);
                goto tx_error;
        }
-- 
2.11.0