ip_tunnel: Add tnl_update_pmtu in ip_md_tunnel_xmit

Add tnl_update_pmtu in ip_md_tunnel_xmit to dynamic modify
the pmtu which packet send through collect_metadata mode
ip tunnel

Signed-off-by: wenxu <wenxu@ucloud.cn>
Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 29 insertions, 12 deletions

diff --git a/include/net/ip_tunnels.h b/include/net/ip_tunnels.h
index 34f019650941..f069f64ebf29 100644
--- a/include/net/ip_tunnels.h
+++ b/include/net/ip_tunnels.h
@@ -267,7 +267,7 @@ void ip_tunnel_delete_nets(struct list_head *list_net, unsigned int id,
 void ip_tunnel_xmit(struct sk_buff *skb, struct net_device *dev,
                     const struct iphdr *tnl_params, const u8 protocol);
 void ip_md_tunnel_xmit(struct sk_buff *skb, struct net_device *dev,
-                       const u8 proto);
+                       const u8 proto, int tunnel_hlen);
 int ip_tunnel_ioctl(struct net_device *dev, struct ip_tunnel_parm *p, int cmd);
 int __ip_tunnel_change_mtu(struct net_device *dev, int new_mtu, bool strict);
 int ip_tunnel_change_mtu(struct net_device *dev, int new_mtu);
diff --git a/net/ipv4/ip_tunnel.c b/net/ipv4/ip_tunnel.c
index f98fc4c983a5..6233a7c434b1 100644
--- a/net/ipv4/ip_tunnel.c
+++ b/net/ipv4/ip_tunnel.c
@@ -501,15 +501,19 @@ 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)
+                            const struct iphdr *inner_iph,
+                            int tunnel_hlen, __be32 dst, bool md)
 {
         struct ip_tunnel *tunnel = netdev_priv(dev);
-        int pkt_size = skb->len - tunnel->hlen - dev->hard_header_len;
+        int pkt_size;
         int mtu;
 
+        tunnel_hlen = md ? tunnel_hlen : tunnel->hlen;
+        pkt_size = skb->len - tunnel_hlen - dev->hard_header_len;
+
         if (df)
                 mtu = dst_mtu(&rt->dst) - dev->hard_header_len
-                                        - sizeof(struct iphdr) - tunnel->hlen;
+                                        - sizeof(struct iphdr) - tunnel_hlen;
         else
                 mtu = skb_dst(skb) ? dst_mtu(skb_dst(skb)) : dev->mtu;
 
@@ -527,11 +531,13 @@ static int tnl_update_pmtu(struct net_device *dev, struct sk_buff *skb,
 #if IS_ENABLED(CONFIG_IPV6)
         else if (skb->protocol == htons(ETH_P_IPV6)) {
                 struct rt6_info *rt6 = (struct rt6_info *)skb_dst(skb);
+                __be32 daddr;
+
+                daddr = md ? dst : tunnel->parms.iph.daddr;
 
                 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);
@@ -548,7 +554,8 @@ static int tnl_update_pmtu(struct net_device *dev, struct sk_buff *skb,
         return 0;
 }
 
-void ip_md_tunnel_xmit(struct sk_buff *skb, struct net_device *dev, u8 proto)
+void ip_md_tunnel_xmit(struct sk_buff *skb, struct net_device *dev,
+                       u8 proto, int tunnel_hlen)
 {
         struct ip_tunnel *tunnel = netdev_priv(dev);
         u32 headroom = sizeof(struct iphdr);
@@ -598,6 +605,15 @@ void ip_md_tunnel_xmit(struct sk_buff *skb, struct net_device *dev, u8 proto)
                 dev->stats.collisions++;
                 goto tx_error;
         }
+
+        if (key->tun_flags & TUNNEL_DONT_FRAGMENT)
+                df = htons(IP_DF);
+        if (tnl_update_pmtu(dev, skb, rt, df, inner_iph, tunnel_hlen,
+                            key->u.ipv4.dst, true)) {
+                ip_rt_put(rt);
+                goto tx_error;
+        }
+
         tos = ip_tunnel_ecn_encap(tos, inner_iph, skb);
         ttl = key->ttl;
         if (ttl == 0) {
@@ -608,10 +624,10 @@ void ip_md_tunnel_xmit(struct sk_buff *skb, struct net_device *dev, u8 proto)
                 else
                         ttl = ip4_dst_hoplimit(&rt->dst);
         }
-        if (key->tun_flags & TUNNEL_DONT_FRAGMENT)
-                df = htons(IP_DF);
-        else if (skb->protocol == htons(ETH_P_IP))
+
+        if (!df && skb->protocol == htons(ETH_P_IP))
                 df = inner_iph->frag_off & htons(IP_DF);
+
         headroom += LL_RESERVED_SPACE(rt->dst.dev) + rt->dst.header_len;
         if (headroom > dev->needed_headroom)
                 dev->needed_headroom = headroom;
@@ -741,7 +757,8 @@ 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 (tnl_update_pmtu(dev, skb, rt, tnl_params->frag_off, inner_iph,
+                            0, 0, false)) {
                 ip_rt_put(rt);
                 goto tx_error;
         }
diff --git a/net/ipv4/ipip.c b/net/ipv4/ipip.c
index 57c5dd283a2c..fe10b9a2efc8 100644
--- a/net/ipv4/ipip.c
+++ b/net/ipv4/ipip.c
@@ -302,7 +302,7 @@ static netdev_tx_t ipip_tunnel_xmit(struct sk_buff *skb,
         skb_set_inner_ipproto(skb, ipproto);
 
         if (tunnel->collect_md)
-                ip_md_tunnel_xmit(skb, dev, ipproto);
+                ip_md_tunnel_xmit(skb, dev, ipproto, 0);
         else
                 ip_tunnel_xmit(skb, dev, tiph, ipproto);
         return NETDEV_TX_OK;