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>

4 files changed, 67 insertions, 51 deletions

diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index 2aa663a..03e5b61 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -677,7 +677,7 @@ static inline int rt_fast_clean(struct rtable *rth)
 static inline int rt_valuable(struct rtable *rth)
 {
 	return (rth->rt_flags & (RTCF_REDIRECTED | RTCF_NOTIFY)) ||
-		(rth->peer && rth->peer->pmtu_expires);
+		(rt_has_peer(rth) && rt_peer_ptr(rth)->pmtu_expires);
 }
 
 static int rt_may_expire(struct rtable *rth, unsigned long tmo1, unsigned long tmo2)
@@ -1325,12 +1325,16 @@ static u32 rt_peer_genid(void)
 
 void rt_bind_peer(struct rtable *rt, __be32 daddr, int create)
 {
-	struct net *net = dev_net(rt->dst.dev);
+	struct inet_peer_base *base;
 	struct inet_peer *peer;
 
-	peer = inet_getpeer_v4(net->ipv4.peers, daddr, create);
+	base = inetpeer_base_ptr(rt->_peer);
+	if (!base)
+		return;
+
+	peer = inet_getpeer_v4(base, daddr, create);
 
-	if (peer && cmpxchg(&rt->peer, NULL, peer) != NULL)
+	if (!rt_set_peer(rt, peer))
 		inet_putpeer(peer);
 	else
 		rt->rt_peer_genid = rt_peer_genid();
@@ -1533,8 +1537,10 @@ static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst)
 						rt_genid(dev_net(dst->dev)));
 			rt_del(hash, rt);
 			ret = NULL;
-		} else if (rt->peer && peer_pmtu_expired(rt->peer)) {
-			dst_metric_set(dst, RTAX_MTU, rt->peer->pmtu_orig);
+		} else if (rt_has_peer(rt)) {
+			struct inet_peer *peer = rt_peer_ptr(rt);
+			if (peer_pmtu_expired(peer))
+				dst_metric_set(dst, RTAX_MTU, peer->pmtu_orig);
 		}
 	}
 	return ret;
@@ -1796,14 +1802,13 @@ static struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie)
 static void ipv4_dst_destroy(struct dst_entry *dst)
 {
 	struct rtable *rt = (struct rtable *) dst;
-	struct inet_peer *peer = rt->peer;
 
 	if (rt->fi) {
 		fib_info_put(rt->fi);
 		rt->fi = NULL;
 	}
-	if (peer) {
-		rt->peer = NULL;
+	if (rt_has_peer(rt)) {
+		struct inet_peer *peer = rt_peer_ptr(rt);
 		inet_putpeer(peer);
 	}
 }
@@ -1816,8 +1821,11 @@ static void ipv4_link_failure(struct sk_buff *skb)
 	icmp_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_UNREACH, 0);
 
 	rt = skb_rtable(skb);
-	if (rt && rt->peer && peer_pmtu_cleaned(rt->peer))
-		dst_metric_set(&rt->dst, RTAX_MTU, rt->peer->pmtu_orig);
+	if (rt && rt_has_peer(rt)) {
+		struct inet_peer *peer = rt_peer_ptr(rt);
+		if (peer_pmtu_cleaned(peer))
+			dst_metric_set(&rt->dst, RTAX_MTU, peer->pmtu_orig);
+	}
 }
 
 static int ip_rt_bug(struct sk_buff *skb)
@@ -1919,7 +1927,7 @@ static unsigned int ipv4_mtu(const struct dst_entry *dst)
 static void rt_init_metrics(struct rtable *rt, const struct flowi4 *fl4,
 			    struct fib_info *fi)
 {
-	struct net *net = dev_net(rt->dst.dev);
+	struct inet_peer_base *base;
 	struct inet_peer *peer;
 	int create = 0;
 
@@ -1929,8 +1937,12 @@ static void rt_init_metrics(struct rtable *rt, const struct flowi4 *fl4,
 	if (fl4 && (fl4->flowi4_flags & FLOWI_FLAG_PRECOW_METRICS))
 		create = 1;
 
-	rt->peer = peer = inet_getpeer_v4(net->ipv4.peers, rt->rt_dst, create);
+	base = inetpeer_base_ptr(rt->_peer);
+	BUG_ON(!base);
+
+	peer = inet_getpeer_v4(base, rt->rt_dst, create);
 	if (peer) {
+		__rt_set_peer(rt, peer);
 		rt->rt_peer_genid = rt_peer_genid();
 		if (inet_metrics_new(peer))
 			memcpy(peer->metrics, fi->fib_metrics,
@@ -2046,7 +2058,7 @@ static int ip_route_input_mc(struct sk_buff *skb, __be32 daddr, __be32 saddr,
 	rth->rt_gateway	= daddr;
 	rth->rt_spec_dst= spec_dst;
 	rth->rt_peer_genid = 0;
-	rth->peer = NULL;
+	rt_init_peer(rth, dev_net(dev)->ipv4.peers);
 	rth->fi = NULL;
 	if (our) {
 		rth->dst.input= ip_local_deliver;
@@ -2174,7 +2186,7 @@ static int __mkroute_input(struct sk_buff *skb,
 	rth->rt_gateway	= daddr;
 	rth->rt_spec_dst= spec_dst;
 	rth->rt_peer_genid = 0;
-	rth->peer = NULL;
+	rt_init_peer(rth, dev_net(rth->dst.dev)->ipv4.peers);
 	rth->fi = NULL;
 
 	rth->dst.input = ip_forward;
@@ -2357,7 +2369,7 @@ local_input:
 	rth->rt_gateway	= daddr;
 	rth->rt_spec_dst= spec_dst;
 	rth->rt_peer_genid = 0;
-	rth->peer = NULL;
+	rt_init_peer(rth, net->ipv4.peers);
 	rth->fi = NULL;
 	if (res.type == RTN_UNREACHABLE) {
 		rth->dst.input= ip_error;
@@ -2561,7 +2573,7 @@ static struct rtable *__mkroute_output(const struct fib_result *res,
 	rth->rt_gateway = fl4->daddr;
 	rth->rt_spec_dst= fl4->saddr;
 	rth->rt_peer_genid = 0;
-	rth->peer = NULL;
+	rt_init_peer(rth, dev_net(dev_out)->ipv4.peers);
 	rth->fi = NULL;
 
 	RT_CACHE_STAT_INC(out_slow_tot);
@@ -2898,9 +2910,7 @@ struct dst_entry *ipv4_blackhole_route(struct net *net, struct dst_entry *dst_or
 		rt->rt_src = ort->rt_src;
 		rt->rt_gateway = ort->rt_gateway;
 		rt->rt_spec_dst = ort->rt_spec_dst;
-		rt->peer = ort->peer;
-		if (rt->peer)
-			atomic_inc(&rt->peer->refcnt);
+		rt_transfer_peer(rt, ort);
 		rt->fi = ort->fi;
 		if (rt->fi)
 			atomic_inc(&rt->fi->fib_clntref);
@@ -2938,7 +2948,6 @@ static int rt_fill_info(struct net *net,
 	struct rtmsg *r;
 	struct nlmsghdr *nlh;
 	unsigned long expires = 0;
-	const struct inet_peer *peer = rt->peer;
 	u32 id = 0, ts = 0, tsage = 0, error;
 
 	nlh = nlmsg_put(skb, pid, seq, event, sizeof(*r), flags);
@@ -2994,8 +3003,9 @@ static int rt_fill_info(struct net *net,
 		goto nla_put_failure;
 
 	error = rt->dst.error;
-	if (peer) {
-		inet_peer_refcheck(rt->peer);
+	if (rt_has_peer(rt)) {
+		const struct inet_peer *peer = rt_peer_ptr(rt);
+		inet_peer_refcheck(peer);
 		id = atomic_read(&peer->ip_id_count) & 0xffff;
 		if (peer->tcp_ts_stamp) {
 			ts = peer->tcp_ts;
diff --git a/net/ipv4/xfrm4_policy.c b/net/ipv4/xfrm4_policy.c
index 0d3426c..8855d82 100644
--- a/net/ipv4/xfrm4_policy.c
+++ b/net/ipv4/xfrm4_policy.c
@@ -90,9 +90,7 @@ static int xfrm4_fill_dst(struct xfrm_dst *xdst, struct net_device *dev,
 	xdst->u.dst.dev = dev;
 	dev_hold(dev);
 
-	xdst->u.rt.peer = rt->peer;
-	if (rt->peer)
-		atomic_inc(&rt->peer->refcnt);
+	rt_transfer_peer(&xdst->u.rt, rt);
 
 	/* Sheit... I remember I did this right. Apparently,
 	 * it was magically lost, so this code needs audit */
@@ -212,8 +210,10 @@ static void xfrm4_dst_destroy(struct dst_entry *dst)
 
 	dst_destroy_metrics_generic(dst);
 
-	if (likely(xdst->u.rt.peer))
-		inet_putpeer(xdst->u.rt.peer);
+	if (rt_has_peer(&xdst->u.rt)) {
+		struct inet_peer *peer = rt_peer_ptr(&xdst->u.rt);
+		inet_putpeer(peer);
+	}
 
 	xfrm_dst_destroy(xdst);
 }
diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index 8fc41d5..17a9b86 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 8625fba..d749484 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);
 }