inet: Hide route peer accesses behind helpers.

We encode the pointer(s) into an unsigned long with one state bit.

The state bit is used so we can store the inetpeer tree root to use
when resolving the peer later.

Later the peer roots will be per-FIB table, and this change works to
facilitate that.

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

2 files changed, 29 insertions, 23 deletions

diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index 8fc41d502bbd..17a9b8687f29 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -258,16 +258,18 @@ static struct rt6_info ip6_blk_hole_entry_template = {
 #endif
 
 /* allocate dst with ip6_dst_ops */
-static inline struct rt6_info *ip6_dst_alloc(struct dst_ops *ops,
+static inline struct rt6_info *ip6_dst_alloc(struct net *net,
                                              struct net_device *dev,
                                              int flags)
 {
-        struct rt6_info *rt = dst_alloc(ops, dev, 0, 0, flags);
+        struct rt6_info *rt = dst_alloc(&net->ipv6.ip6_dst_ops, dev,
+                                        0, 0, flags);
 
-        if (rt)
+        if (rt) {
                 memset(&rt->rt6i_table, 0,
                        sizeof(*rt) - sizeof(struct dst_entry));
-
+                rt6_init_peer(rt, net->ipv6.peers);
+        }
         return rt;
 }
 
@@ -275,7 +277,6 @@ static void ip6_dst_destroy(struct dst_entry *dst)
 {
         struct rt6_info *rt = (struct rt6_info *)dst;
         struct inet6_dev *idev = rt->rt6i_idev;
-        struct inet_peer *peer = rt->rt6i_peer;
 
         if (!(rt->dst.flags & DST_HOST))
                 dst_destroy_metrics_generic(dst);
@@ -288,8 +289,8 @@ static void ip6_dst_destroy(struct dst_entry *dst)
         if (!(rt->rt6i_flags & RTF_EXPIRES) && dst->from)
                 dst_release(dst->from);
 
-        if (peer) {
-                rt->rt6i_peer = NULL;
+        if (rt6_has_peer(rt)) {
+                struct inet_peer *peer = rt6_peer_ptr(rt);
                 inet_putpeer(peer);
         }
 }
@@ -303,11 +304,15 @@ static u32 rt6_peer_genid(void)
 
 void rt6_bind_peer(struct rt6_info *rt, int create)
 {
-        struct net *net = dev_net(rt->dst.dev);
+        struct inet_peer_base *base;
         struct inet_peer *peer;
 
-        peer = inet_getpeer_v6(net->ipv6.peers, &rt->rt6i_dst.addr, create);
-        if (peer && cmpxchg(&rt->rt6i_peer, NULL, peer) != NULL)
+        base = inetpeer_base_ptr(rt->_rt6i_peer);
+        if (!base)
+                return;
+
+        peer = inet_getpeer_v6(base, &rt->rt6i_dst.addr, create);
+        if (!rt6_set_peer(rt, peer))
                 inet_putpeer(peer);
         else
                 rt->rt6i_peer_genid = rt6_peer_genid();
@@ -950,6 +955,7 @@ struct dst_entry *ip6_blackhole_route(struct net *net, struct dst_entry *dst_ori
         rt = dst_alloc(&ip6_dst_blackhole_ops, ort->dst.dev, 1, 0, 0);
         if (rt) {
                 memset(&rt->rt6i_table, 0, sizeof(*rt) - sizeof(struct dst_entry));
+                rt6_init_peer(rt, net->ipv6.peers);
 
                 new = &rt->dst;
 
@@ -994,7 +1000,7 @@ static struct dst_entry *ip6_dst_check(struct dst_entry *dst, u32 cookie)
 
         if (rt->rt6i_node && (rt->rt6i_node->fn_sernum == cookie)) {
                 if (rt->rt6i_peer_genid != rt6_peer_genid()) {
-                        if (!rt->rt6i_peer)
+                        if (!rt6_has_peer(rt))
                                 rt6_bind_peer(rt, 0);
                         rt->rt6i_peer_genid = rt6_peer_genid();
                 }
@@ -1108,7 +1114,7 @@ struct dst_entry *icmp6_dst_alloc(struct net_device *dev,
         if (unlikely(!idev))
                 return ERR_PTR(-ENODEV);
 
-        rt = ip6_dst_alloc(&net->ipv6.ip6_dst_ops, dev, 0);
+        rt = ip6_dst_alloc(net, dev, 0);
         if (unlikely(!rt)) {
                 in6_dev_put(idev);
                 dst = ERR_PTR(-ENOMEM);
@@ -1290,7 +1296,7 @@ int ip6_route_add(struct fib6_config *cfg)
         if (!table)
                 goto out;
 
-        rt = ip6_dst_alloc(&net->ipv6.ip6_dst_ops, NULL, DST_NOCOUNT);
+        rt = ip6_dst_alloc(net, NULL, DST_NOCOUNT);
 
         if (!rt) {
                 err = -ENOMEM;
@@ -1812,8 +1818,7 @@ static struct rt6_info *ip6_rt_copy(struct rt6_info *ort,
                                     const struct in6_addr *dest)
 {
         struct net *net = dev_net(ort->dst.dev);
-        struct rt6_info *rt = ip6_dst_alloc(&net->ipv6.ip6_dst_ops,
-                                            ort->dst.dev, 0);
+        struct rt6_info *rt = ip6_dst_alloc(net, ort->dst.dev, 0);
 
         if (rt) {
                 rt->dst.input = ort->dst.input;
@@ -2097,8 +2102,7 @@ struct rt6_info *addrconf_dst_alloc(struct inet6_dev *idev,
                                     bool anycast)
 {
         struct net *net = dev_net(idev->dev);
-        struct rt6_info *rt = ip6_dst_alloc(&net->ipv6.ip6_dst_ops,
-                                            net->loopback_dev, 0);
+        struct rt6_info *rt = ip6_dst_alloc(net, net->loopback_dev, 0);
         int err;
 
         if (!rt) {
@@ -2519,7 +2523,9 @@ static int rt6_fill_node(struct net *net,
         else
                 expires = INT_MAX;
 
-        peer = rt->rt6i_peer;
+        peer = NULL;
+        if (rt6_has_peer(rt))
+                peer = rt6_peer_ptr(rt);
         ts = tsage = 0;
         if (peer && peer->tcp_ts_stamp) {
                 ts = peer->tcp_ts;
diff --git a/net/ipv6/xfrm6_policy.c b/net/ipv6/xfrm6_policy.c
index 8625fba96db9..d7494845efbf 100644
--- a/net/ipv6/xfrm6_policy.c
+++ b/net/ipv6/xfrm6_policy.c
@@ -99,9 +99,7 @@ static int xfrm6_fill_dst(struct xfrm_dst *xdst, struct net_device *dev,
         if (!xdst->u.rt6.rt6i_idev)
                 return -ENODEV;
 
-        xdst->u.rt6.rt6i_peer = rt->rt6i_peer;
-        if (rt->rt6i_peer)
-                atomic_inc(&rt->rt6i_peer->refcnt);
+        rt6_transfer_peer(&xdst->u.rt6, rt);
 
         /* Sheit... I remember I did this right. Apparently,
          * it was magically lost, so this code needs audit */
@@ -223,8 +221,10 @@ static void xfrm6_dst_destroy(struct dst_entry *dst)
         if (likely(xdst->u.rt6.rt6i_idev))
                 in6_dev_put(xdst->u.rt6.rt6i_idev);
         dst_destroy_metrics_generic(dst);
-        if (likely(xdst->u.rt6.rt6i_peer))
-                inet_putpeer(xdst->u.rt6.rt6i_peer);
+        if (rt6_has_peer(&xdst->u.rt6)) {
+                struct inet_peer *peer = rt6_peer_ptr(&xdst->u.rt6);
+                inet_putpeer(peer);
+        }
         xfrm_dst_destroy(xdst);
 }