Revert "ipv4: tcp: dont cache unconfirmed intput dst"

This reverts commit c074da2810c118b3812f32d6754bd9ead2f169e7.

This change has several unwanted side effects:

1) Sockets will cache the DST_NOCACHE route in sk->sk_rx_dst and we'll
   thus never create a real cached route.

2) All TCP traffic will use DST_NOCACHE and never use the routing
   cache at all.

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

9 files changed, 15 insertions, 20 deletions

diff --git a/include/net/protocol.h b/include/net/protocol.h
index 7cfc8f76914d..967b926cbfb1 100644
--- a/include/net/protocol.h
+++ b/include/net/protocol.h
@@ -37,7 +37,7 @@
 
 /* This is used to register protocols. */
 struct net_protocol {
-        int                     (*early_demux)(struct sk_buff *skb, bool *nocache);
+        int                     (*early_demux)(struct sk_buff *skb);
         int                     (*handler)(struct sk_buff *skb);
         void                    (*err_handler)(struct sk_buff *skb, u32 info);
         int                     (*gso_send_check)(struct sk_buff *skb);
diff --git a/include/net/route.h b/include/net/route.h
index 6361f9335774..47eb25ac1f7f 100644
--- a/include/net/route.h
+++ b/include/net/route.h
@@ -201,18 +201,18 @@ static inline struct rtable *ip_route_output_gre(struct net *net, struct flowi4
 }
 
 extern int ip_route_input_common(struct sk_buff *skb, __be32 dst, __be32 src,
-                                 u8 tos, struct net_device *devin, bool noref, bool nocache);
+                                 u8 tos, struct net_device *devin, bool noref);
 
 static inline int ip_route_input(struct sk_buff *skb, __be32 dst, __be32 src,
                                  u8 tos, struct net_device *devin)
 {
-        return ip_route_input_common(skb, dst, src, tos, devin, false, false);
+        return ip_route_input_common(skb, dst, src, tos, devin, false);
 }
 
 static inline int ip_route_input_noref(struct sk_buff *skb, __be32 dst, __be32 src,
-                                       u8 tos, struct net_device *devin, bool nocache)
+                                       u8 tos, struct net_device *devin)
 {
-        return ip_route_input_common(skb, dst, src, tos, devin, true, nocache);
+        return ip_route_input_common(skb, dst, src, tos, devin, true);
 }
 
 extern void ipv4_update_pmtu(struct sk_buff *skb, struct net *net, u32 mtu,
diff --git a/include/net/tcp.h b/include/net/tcp.h
index 917ed2e55e8c..6660ffc4963d 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -325,7 +325,7 @@ extern void tcp_v4_err(struct sk_buff *skb, u32);
 
 extern void tcp_shutdown (struct sock *sk, int how);
 
-extern int tcp_v4_early_demux(struct sk_buff *skb, bool *nocache);
+extern int tcp_v4_early_demux(struct sk_buff *skb);
 extern int tcp_v4_rcv(struct sk_buff *skb);
 
 extern struct inet_peer *tcp_v4_get_peer(struct sock *sk);
diff --git a/net/ipv4/arp.c b/net/ipv4/arp.c
index 6a9795944369..2e560f0c757d 100644
--- a/net/ipv4/arp.c
+++ b/net/ipv4/arp.c
@@ -828,7 +828,7 @@ static int arp_process(struct sk_buff *skb)
         }
 
         if (arp->ar_op == htons(ARPOP_REQUEST) &&
-            ip_route_input_noref(skb, tip, sip, 0, dev, false) == 0) {
+            ip_route_input_noref(skb, tip, sip, 0, dev) == 0) {
 
                 rt = skb_rtable(skb);
                 addr_type = rt->rt_type;
diff --git a/net/ipv4/ip_fragment.c b/net/ipv4/ip_fragment.c
index 978d55f256ea..8d07c973409c 100644
--- a/net/ipv4/ip_fragment.c
+++ b/net/ipv4/ip_fragment.c
@@ -259,7 +259,7 @@ static void ip_expire(unsigned long arg)
                 skb_dst_drop(head);
                 iph = ip_hdr(head);
                 err = ip_route_input_noref(head, iph->daddr, iph->saddr,
-                                           iph->tos, head->dev, false);
+                                           iph->tos, head->dev);
                 if (err)
                         goto out_rcu_unlock;
 
diff --git a/net/ipv4/ip_input.c b/net/ipv4/ip_input.c
index 7be54c8dcbe2..2a39204de5bc 100644
--- a/net/ipv4/ip_input.c
+++ b/net/ipv4/ip_input.c
@@ -326,7 +326,6 @@ static int ip_rcv_finish(struct sk_buff *skb)
          */
         if (skb_dst(skb) == NULL) {
                 int err = -ENOENT;
-                bool nocache = false;
 
                 if (sysctl_ip_early_demux) {
                         const struct net_protocol *ipprot;
@@ -335,13 +334,13 @@ static int ip_rcv_finish(struct sk_buff *skb)
                         rcu_read_lock();
                         ipprot = rcu_dereference(inet_protos[protocol]);
                         if (ipprot && ipprot->early_demux)
-                                err = ipprot->early_demux(skb, &nocache);
+                                err = ipprot->early_demux(skb);
                         rcu_read_unlock();
                 }
 
                 if (err) {
                         err = ip_route_input_noref(skb, iph->daddr, iph->saddr,
-                                                   iph->tos, skb->dev, nocache);
+                                                   iph->tos, skb->dev);
                         if (unlikely(err)) {
                                 if (err == -EXDEV)
                                         NET_INC_STATS_BH(dev_net(skb->dev),
diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index fdc7900f9d7a..81533e3a23d1 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -2214,7 +2214,7 @@ static int ip_mkroute_input(struct sk_buff *skb,
  */
 
 static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr,
-                               u8 tos, struct net_device *dev, bool nocache)
+                               u8 tos, struct net_device *dev)
 {
         struct fib_result res;
         struct in_device *in_dev = __in_dev_get_rcu(dev);
@@ -2353,8 +2353,6 @@ local_input:
                 rth->dst.error= -err;
                 rth->rt_flags   &= ~RTCF_LOCAL;
         }
-        if (nocache)
-                rth->dst.flags |= DST_NOCACHE;
         hash = rt_hash(daddr, saddr, fl4.flowi4_iif, rt_genid(net));
         rth = rt_intern_hash(hash, rth, skb, fl4.flowi4_iif);
         err = 0;
@@ -2397,7 +2395,7 @@ martian_source_keep_err:
 }
 
 int ip_route_input_common(struct sk_buff *skb, __be32 daddr, __be32 saddr,
-                           u8 tos, struct net_device *dev, bool noref, bool nocache)
+                           u8 tos, struct net_device *dev, bool noref)
 {
         struct rtable   *rth;
         unsigned int    hash;
@@ -2473,7 +2471,7 @@ skip_cache:
                 rcu_read_unlock();
                 return -EINVAL;
         }
-        res = ip_route_input_slow(skb, daddr, saddr, tos, dev, nocache);
+        res = ip_route_input_slow(skb, daddr, saddr, tos, dev);
         rcu_read_unlock();
         return res;
 }
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index 33aabd4fc20f..1781dc650b9d 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -1673,7 +1673,7 @@ csum_err:
 }
 EXPORT_SYMBOL(tcp_v4_do_rcv);
 
-int tcp_v4_early_demux(struct sk_buff *skb, bool *no_dst_cache)
+int tcp_v4_early_demux(struct sk_buff *skb)
 {
         struct net *net = dev_net(skb->dev);
         const struct iphdr *iph;
@@ -1719,8 +1719,6 @@ int tcp_v4_early_demux(struct sk_buff *skb, bool *no_dst_cache)
                                 }
                         }
                 }
-        } else {
-                *no_dst_cache = true;
         }
 
 out_err:
diff --git a/net/ipv4/xfrm4_input.c b/net/ipv4/xfrm4_input.c
index eee636b191b9..06814b6216dc 100644
--- a/net/ipv4/xfrm4_input.c
+++ b/net/ipv4/xfrm4_input.c
@@ -28,7 +28,7 @@ static inline int xfrm4_rcv_encap_finish(struct sk_buff *skb)
                 const struct iphdr *iph = ip_hdr(skb);
 
                 if (ip_route_input_noref(skb, iph->daddr, iph->saddr,
-                                         iph->tos, skb->dev, false))
+                                         iph->tos, skb->dev))
                         goto drop;
         }
         return dst_input(skb);