Merge branch 'metrics_restructure'

This patch series works towards the goal of minimizing the amount
of things that can change in an ipv4 route.

In a regime where the routing cache is removed, route changes will
lead to cloning in the FIB tables or similar.

The largest trigger of route metrics writes, TCP, now has it's own
cache of dynamic metric state.  The timewait timestamps are stored
there now as well.

As a result of that, pre-cowing metrics is no longer necessary,
and therefore FLOWI_FLAG_PRECOW_METRICS is removed.

Redirect and PMTU handling is moved back into the ipv4 routes.  I'm
sorry for all the headaches trying to do this in the inetpeer has
caused, it was the wrong approach for sure.

Since metrics become read-only for ipv4 we no longer need the inetpeer
hung off of the ipv4 routes either.  So those disappear too.

Also, timewait sockets no longer need to hold onto an inetpeer either.

After this series, we still have some details to resolve wrt. PMTU and
redirects for a route-cache-less system:

1) With just the plain route cache removal, PMTU will continue to
   work mostly fine.  This is because of how the local route users
   call down into the PMTU update code with the route they already
   hold.

   However, if we wish to cache pre-computed routes in fib_info
   nexthops (which we want for performance), then we need to add
   route cloning for PMTU events.

2) Redirects require more work.  First, redirects must be changed to
   be handled like PMTU.  Wherein we call down into the sockets and
   other entities, and then they call back into the routing code with
   the route they were using.

   So we'll be adding an ->update_nexthop() method alongside
   ->update_pmtu().

   And then, like for PMTU, we'll need cloning support once we start
   caching routes in the fib_info nexthops.

But that's it, we can completely pull the trigger and remove the
routing cache with minimal disruptions.

As it is, this patch series alone helps a lot of things.  For one,
routing cache entry creation should be a lot faster, because we no
longer do inetpeer lookups (even to check if an entry exists).

This patch series also opens the door for non-DST_HOST ipv4 routes,
because nothing fundamentally cares about rt->rt_dst any more.  It
can be removed with the base routing cache removal patch.  In fact,
that was the primary goal of this patch series.
Signed-off-by: David S. Miller <davem@davemloft.net>

include/linux/rtnetlink.h

@@ -619,8 +619,7 @@ extern void rtnl_notify(struct sk_buff *skb, struct net *net, u32 pid,
 extern void rtnl_set_sk_err(struct net *net, u32 group, int error);
 extern int rtnetlink_put_metrics(struct sk_buff *skb, u32 *metrics);
 extern int rtnl_put_cacheinfo(struct sk_buff *skb, struct dst_entry *dst,
-			      u32 id, u32 ts, u32 tsage, long expires,
-			      u32 error);
+			      u32 id, long expires, u32 error);
 
 extern void rtmsg_ifinfo(int type, struct net_device *dev, unsigned change);
 

include/linux/tcp.h

@@ -506,7 +506,6 @@ struct tcp_timewait_sock {
 	u32			  tw_rcv_wnd;
 	u32			  tw_ts_recent;
 	long			  tw_ts_recent_stamp;
-	struct inet_peer	  *tw_peer;
 #ifdef CONFIG_TCP_MD5SIG
 	struct tcp_md5sig_key	  *tw_md5_key;
 #endif

include/net/dst.h

@@ -209,12 +209,6 @@ static inline unsigned long dst_metric_rtt(const struct dst_entry *dst, int metr
 	return msecs_to_jiffies(dst_metric(dst, metric));
 }
 
-static inline void set_dst_metric_rtt(struct dst_entry *dst, int metric,
-				      unsigned long rtt)
-{
-	dst_metric_set(dst, metric, jiffies_to_msecs(rtt));
-}
-
 static inline u32
 dst_allfrag(const struct dst_entry *dst)
 {

include/net/flow.h

@@ -20,9 +20,8 @@ struct flowi_common {
 	__u8	flowic_proto;
 	__u8	flowic_flags;
 #define FLOWI_FLAG_ANYSRC		0x01
-#define FLOWI_FLAG_PRECOW_METRICS	0x02
-#define FLOWI_FLAG_CAN_SLEEP		0x04
-#define FLOWI_FLAG_RT_NOCACHE		0x08
+#define FLOWI_FLAG_CAN_SLEEP		0x02
+#define FLOWI_FLAG_RT_NOCACHE		0x04
 	__u32	flowic_secid;
 };
 

include/net/inet_connection_sock.h

@@ -43,7 +43,6 @@ struct inet_connection_sock_af_ops {
 	struct sock *(*syn_recv_sock)(struct sock *sk, struct sk_buff *skb,
 				      struct request_sock *req,
 				      struct dst_entry *dst);
-	struct inet_peer *(*get_peer)(struct sock *sk);
 	u16	    net_header_len;
 	u16	    net_frag_header_len;
 	u16	    sockaddr_len;

include/net/inet_sock.h

@@ -245,8 +245,6 @@ static inline __u8 inet_sk_flowi_flags(const struct sock *sk)
 
 	if (inet_sk(sk)->transparent || inet_sk(sk)->hdrincl)
 		flags |= FLOWI_FLAG_ANYSRC;
-	if (sk->sk_protocol == IPPROTO_TCP)
-		flags |= FLOWI_FLAG_PRECOW_METRICS;
 	return flags;
 }
 

include/net/inetpeer.h

@@ -36,25 +36,19 @@ struct inet_peer {
 	u32			metrics[RTAX_MAX];
 	u32			rate_tokens;	/* rate limiting for ICMP */
 	unsigned long		rate_last;
-	unsigned long		pmtu_expires;
-	u32			pmtu_orig;
-	u32			pmtu_learned;
-	struct inetpeer_addr_base redirect_learned;
 	union {
 		struct list_head	gc_list;
 		struct rcu_head     gc_rcu;
 	};
 	/*
 	 * Once inet_peer is queued for deletion (refcnt == -1), following fields
-	 * are not available: rid, ip_id_count, tcp_ts, tcp_ts_stamp
+	 * are not available: rid, ip_id_count
 	 * We can share memory with rcu_head to help keep inet_peer small.
 	 */
 	union {
 		struct {
 			atomic_t			rid;		/* Frag reception counter */
 			atomic_t			ip_id_count;	/* IP ID for the next packet */
-			__u32				tcp_ts;
-			__u32				tcp_ts_stamp;
 		};
 		struct rcu_head         rcu;
 		struct inet_peer	*gc_next;

include/net/netns/ipv4.h

@@ -7,6 +7,7 @@
 
 #include <net/inet_frag.h>
 
+struct tcpm_hash_bucket;
 struct ctl_table_header;
 struct ipv4_devconf;
 struct fib_rules_ops;
@@ -39,6 +40,8 @@ struct netns_ipv4 {
 	struct sock		**icmp_sk;
 	struct sock		*tcp_sock;
 	struct inet_peer_base	*peers;
+	struct tcpm_hash_bucket	*tcp_metrics_hash;
+	unsigned int		tcp_metrics_hash_mask;
 	struct netns_frags	frags;
 #ifdef CONFIG_NETFILTER
 	struct xt_table		*iptable_filter;

include/net/route.h

@@ -40,7 +40,6 @@
 #define RT_CONN_FLAGS(sk)   (RT_TOS(inet_sk(sk)->tos) | sock_flag(sk, SOCK_LOCALROUTE))
 
 struct fib_nh;
-struct inet_peer;
 struct fib_info;
 struct rtable {
 	struct dst_entry	dst;
@@ -65,45 +64,10 @@ struct rtable {
 	__be32			rt_gateway;
 
 	/* Miscellaneous cached information */
-	u32			rt_peer_genid;
-	unsigned long		_peer; /* long-living peer info */
+	u32			rt_pmtu;
 	struct fib_info		*fi; /* for client ref to shared metrics */
 };
 
-static inline struct inet_peer *rt_peer_ptr(struct rtable *rt)
-{
-	return inetpeer_ptr(rt->_peer);
-}
-
-static inline bool rt_has_peer(struct rtable *rt)
-{
-	return inetpeer_ptr_is_peer(rt->_peer);
-}
-
-static inline void __rt_set_peer(struct rtable *rt, struct inet_peer *peer)
-{
-	__inetpeer_ptr_set_peer(&rt->_peer, peer);
-}
-
-static inline bool rt_set_peer(struct rtable *rt, struct inet_peer *peer)
-{
-	return inetpeer_ptr_set_peer(&rt->_peer, peer);
-}
-
-static inline void rt_init_peer(struct rtable *rt, struct inet_peer_base *base)
-{
-	inetpeer_init_ptr(&rt->_peer, base);
-}
-
-static inline void rt_transfer_peer(struct rtable *rt, struct rtable *ort)
-{
-	rt->_peer = ort->_peer;
-	if (rt_has_peer(ort)) {
-		struct inet_peer *peer = rt_peer_ptr(ort);
-		atomic_inc(&peer->refcnt);
-	}
-}
-
 static inline bool rt_is_input_route(const struct rtable *rt)
 {
 	return rt->rt_route_iif != 0;
@@ -278,8 +242,6 @@ static inline void ip_route_connect_init(struct flowi4 *fl4, __be32 dst, __be32
 
 	if (inet_sk(sk)->transparent)
 		flow_flags |= FLOWI_FLAG_ANYSRC;
-	if (protocol == IPPROTO_TCP)
-		flow_flags |= FLOWI_FLAG_PRECOW_METRICS;
 	if (can_sleep)
 		flow_flags |= FLOWI_FLAG_CAN_SLEEP;
 
@@ -328,27 +290,6 @@ static inline struct rtable *ip_route_newports(struct flowi4 *fl4, struct rtable
 	return rt;
 }
 
-extern void rt_bind_peer(struct rtable *rt, __be32 daddr, int create);
-
-static inline struct inet_peer *__rt_get_peer(struct rtable *rt, __be32 daddr, int create)
-{
-	if (rt_has_peer(rt))
-		return rt_peer_ptr(rt);
-
-	rt_bind_peer(rt, daddr, create);
-	return (rt_has_peer(rt) ? rt_peer_ptr(rt) : NULL);
-}
-
-static inline struct inet_peer *rt_get_peer(struct rtable *rt, __be32 daddr)
-{
-	return __rt_get_peer(rt, daddr, 0);
-}
-
-static inline struct inet_peer *rt_get_peer_create(struct rtable *rt, __be32 daddr)
-{
-	return __rt_get_peer(rt, daddr, 1);
-}
-
 static inline int inet_iif(const struct sk_buff *skb)
 {
 	return skb_rtable(skb)->rt_iif;

include/net/tcp.h

@@ -388,6 +388,13 @@ extern void tcp_enter_frto(struct sock *sk);
 extern void tcp_enter_loss(struct sock *sk, int how);
 extern void tcp_clear_retrans(struct tcp_sock *tp);
 extern void tcp_update_metrics(struct sock *sk);
+extern void tcp_init_metrics(struct sock *sk);
+extern void tcp_metrics_init(void);
+extern bool tcp_peer_is_proven(struct request_sock *req, struct dst_entry *dst, bool paws_check);
+extern bool tcp_remember_stamp(struct sock *sk);
+extern bool tcp_tw_remember_stamp(struct inet_timewait_sock *tw);
+extern void tcp_fetch_timewait_stamp(struct sock *sk, struct dst_entry *dst);
+extern void tcp_disable_fack(struct tcp_sock *tp);
 extern void tcp_close(struct sock *sk, long timeout);
 extern void tcp_init_sock(struct sock *sk);
 extern unsigned int tcp_poll(struct file * file, struct socket *sock,
@@ -556,6 +563,8 @@ static inline u32 __tcp_set_rto(const struct tcp_sock *tp)
 	return (tp->srtt >> 3) + tp->rttvar;
 }
 
+extern void tcp_set_rto(struct sock *sk);
+
 static inline void __tcp_fast_path_on(struct tcp_sock *tp, u32 snd_wnd)
 {
 	tp->pred_flags = htonl((tp->tcp_header_len << 26) |

net/core/rtnetlink.c

@@ -615,7 +615,7 @@ int rtnetlink_put_metrics(struct sk_buff *skb, u32 *metrics)
 EXPORT_SYMBOL(rtnetlink_put_metrics);
 
 int rtnl_put_cacheinfo(struct sk_buff *skb, struct dst_entry *dst, u32 id,
-		       u32 ts, u32 tsage, long expires, u32 error)
+		       long expires, u32 error)
 {
 	struct rta_cacheinfo ci = {
 		.rta_lastuse = jiffies_to_clock_t(jiffies - dst->lastuse),
@@ -623,8 +623,6 @@ int rtnl_put_cacheinfo(struct sk_buff *skb, struct dst_entry *dst, u32 id,
 		.rta_clntref = atomic_read(&(dst->__refcnt)),
 		.rta_error = error,
 		.rta_id =  id,
-		.rta_ts = ts,
-		.rta_tsage = tsage,
 	};
 
 	if (expires)

net/decnet/dn_route.c

@@ -1590,7 +1590,7 @@ static int dn_rt_fill_info(struct sk_buff *skb, u32 pid, u32 seq,
 		goto errout;
 
 	expires = rt->dst.expires ? rt->dst.expires - jiffies : 0;
-	if (rtnl_put_cacheinfo(skb, &rt->dst, 0, 0, 0, expires,
+	if (rtnl_put_cacheinfo(skb, &rt->dst, 0, expires,
 			       rt->dst.error) < 0)
 		goto errout;
 
@@ -1816,8 +1816,7 @@ static int dn_rt_cache_seq_show(struct seq_file *seq, void *v)
 		   dn_addr2asc(le16_to_cpu(rt->rt_daddr), buf1),
 		   dn_addr2asc(le16_to_cpu(rt->rt_saddr), buf2),
 		   atomic_read(&rt->dst.__refcnt),
-			rt->dst.__use,
-			(int) dst_metric(&rt->dst, RTAX_RTT));
+		   rt->dst.__use, 0);
 	return 0;
 }
 

net/ipv4/Makefile

@@ -7,7 +7,7 @@ obj-y     := route.o inetpeer.o protocol.o \
 	     ip_output.o ip_sockglue.o inet_hashtables.o \
 	     inet_timewait_sock.o inet_connection_sock.o \
 	     tcp.o tcp_input.o tcp_output.o tcp_timer.o tcp_ipv4.o \
-	     tcp_minisocks.o tcp_cong.o \
+	     tcp_minisocks.o tcp_cong.o tcp_metrics.o \
 	     datagram.o raw.o udp.o udplite.o \
 	     arp.o icmp.o devinet.o af_inet.o  igmp.o \
 	     fib_frontend.o fib_semantics.o fib_trie.o \

net/ipv4/fib_semantics.c

@@ -794,6 +794,8 @@ struct fib_info *fib_create_info(struct fib_config *cfg)
 				val = nla_get_u32(nla);
 				if (type == RTAX_ADVMSS && val > 65535 - 40)
 					val = 65535 - 40;
+				if (type == RTAX_MTU && val > 65535 - 15)
+					val = 65535 - 15;
 				fi->fib_metrics[type - 1] = val;
 			}
 		}

net/ipv4/icmp.c

@@ -254,9 +254,10 @@ static inline bool icmpv4_xrlim_allow(struct net *net, struct rtable *rt,
 
 	/* Limit if icmp type is enabled in ratemask. */
 	if ((1 << type) & net->ipv4.sysctl_icmp_ratemask) {
-		struct inet_peer *peer = rt_get_peer_create(rt, fl4->daddr);
+		struct inet_peer *peer = inet_getpeer_v4(net->ipv4.peers, fl4->daddr, 1);
 		rc = inet_peer_xrlim_allow(peer,
 					   net->ipv4.sysctl_icmp_ratelimit);
+		inet_putpeer(peer);
 	}
 out:
 	return rc;

net/ipv4/inet_connection_sock.c

@@ -375,7 +375,7 @@ struct dst_entry *inet_csk_route_req(struct sock *sk,
 	const struct inet_request_sock *ireq = inet_rsk(req);
 	struct ip_options_rcu *opt = inet_rsk(req)->opt;
 	struct net *net = sock_net(sk);
-	int flags = inet_sk_flowi_flags(sk) & ~FLOWI_FLAG_PRECOW_METRICS;
+	int flags = inet_sk_flowi_flags(sk);
 
 	if (nocache)
 		flags |= FLOWI_FLAG_RT_NOCACHE;

net/ipv4/inetpeer.c

@@ -508,13 +508,9 @@ struct inet_peer *inet_getpeer(struct inet_peer_base *base,
 				(daddr->family == AF_INET) ?
 					secure_ip_id(daddr->addr.a4) :
 					secure_ipv6_id(daddr->addr.a6));
-		p->tcp_ts_stamp = 0;
 		p->metrics[RTAX_LOCK-1] = INETPEER_METRICS_NEW;
 		p->rate_tokens = 0;
 		p->rate_last = 0;
-		p->pmtu_expires = 0;
-		p->pmtu_orig = 0;
-		memset(&p->redirect_learned, 0, sizeof(p->redirect_learned));
 		INIT_LIST_HEAD(&p->gc_list);
 
 		/* Link the node. */

net/ipv4/tcp.c

@@ -3563,6 +3563,8 @@ void __init tcp_init(void)
 	pr_info("Hash tables configured (established %u bind %u)\n",
 		tcp_hashinfo.ehash_mask + 1, tcp_hashinfo.bhash_size);
 
+	tcp_metrics_init();
+
 	tcp_register_congestion_control(&tcp_reno);
 
 	memset(&tcp_secret_one.secrets[0], 0, sizeof(tcp_secret_one.secrets));

net/ipv4/tcp_input.c

@@ -93,7 +93,6 @@ int sysctl_tcp_rfc1337 __read_mostly;
 int sysctl_tcp_max_orphans __read_mostly = NR_FILE;
 int sysctl_tcp_frto __read_mostly = 2;
 int sysctl_tcp_frto_response __read_mostly;
-int sysctl_tcp_nometrics_save __read_mostly;
 
 int sysctl_tcp_thin_dupack __read_mostly;
 
@@ -701,7 +700,7 @@ static void tcp_rtt_estimator(struct sock *sk, const __u32 mrtt)
 /* Calculate rto without backoff.  This is the second half of Van Jacobson's
  * routine referred to above.
  */
-static inline void tcp_set_rto(struct sock *sk)
+void tcp_set_rto(struct sock *sk)
 {
 	const struct tcp_sock *tp = tcp_sk(sk);
 	/* Old crap is replaced with new one. 8)
@@ -728,109 +727,6 @@ static inline void tcp_set_rto(struct sock *sk)
 	tcp_bound_rto(sk);
 }
 
-/* Save metrics learned by this TCP session.
-   This function is called only, when TCP finishes successfully
-   i.e. when it enters TIME-WAIT or goes from LAST-ACK to CLOSE.
- */
-void tcp_update_metrics(struct sock *sk)
-{
-	struct tcp_sock *tp = tcp_sk(sk);
-	struct dst_entry *dst = __sk_dst_get(sk);
-
-	if (sysctl_tcp_nometrics_save)
-		return;
-
-	if (dst && (dst->flags & DST_HOST)) {
-		const struct inet_connection_sock *icsk = inet_csk(sk);
-		int m;
-		unsigned long rtt;
-
-		dst_confirm(dst);
-
-		if (icsk->icsk_backoff || !tp->srtt) {
-			/* This session failed to estimate rtt. Why?
-			 * Probably, no packets returned in time.
-			 * Reset our results.
-			 */
-			if (!(dst_metric_locked(dst, RTAX_RTT)))
-				dst_metric_set(dst, RTAX_RTT, 0);
-			return;
-		}
-
-		rtt = dst_metric_rtt(dst, RTAX_RTT);
-		m = rtt - tp->srtt;
-
-		/* If newly calculated rtt larger than stored one,
-		 * store new one. Otherwise, use EWMA. Remember,
-		 * rtt overestimation is always better than underestimation.
-		 */
-		if (!(dst_metric_locked(dst, RTAX_RTT))) {
-			if (m <= 0)
-				set_dst_metric_rtt(dst, RTAX_RTT, tp->srtt);
-			else
-				set_dst_metric_rtt(dst, RTAX_RTT, rtt - (m >> 3));
-		}
-
-		if (!(dst_metric_locked(dst, RTAX_RTTVAR))) {
-			unsigned long var;
-			if (m < 0)
-				m = -m;
-
-			/* Scale deviation to rttvar fixed point */
-			m >>= 1;
-			if (m < tp->mdev)
-				m = tp->mdev;
-
-			var = dst_metric_rtt(dst, RTAX_RTTVAR);
-			if (m >= var)
-				var = m;
-			else
-				var -= (var - m) >> 2;
-
-			set_dst_metric_rtt(dst, RTAX_RTTVAR, var);
-		}
-
-		if (tcp_in_initial_slowstart(tp)) {
-			/* Slow start still did not finish. */
-			if (dst_metric(dst, RTAX_SSTHRESH) &&
-			    !dst_metric_locked(dst, RTAX_SSTHRESH) &&
-			    (tp->snd_cwnd >> 1) > dst_metric(dst, RTAX_SSTHRESH))
-				dst_metric_set(dst, RTAX_SSTHRESH, tp->snd_cwnd >> 1);
-			if (!dst_metric_locked(dst, RTAX_CWND) &&
-			    tp->snd_cwnd > dst_metric(dst, RTAX_CWND))
-				dst_metric_set(dst, RTAX_CWND, tp->snd_cwnd);
-		} else if (tp->snd_cwnd > tp->snd_ssthresh &&
-			   icsk->icsk_ca_state == TCP_CA_Open) {
-			/* Cong. avoidance phase, cwnd is reliable. */
-			if (!dst_metric_locked(dst, RTAX_SSTHRESH))
-				dst_metric_set(dst, RTAX_SSTHRESH,
-					       max(tp->snd_cwnd >> 1, tp->snd_ssthresh));
-			if (!dst_metric_locked(dst, RTAX_CWND))
-				dst_metric_set(dst, RTAX_CWND,
-					       (dst_metric(dst, RTAX_CWND) +
-						tp->snd_cwnd) >> 1);
-		} else {
-			/* Else slow start did not finish, cwnd is non-sense,
-			   ssthresh may be also invalid.
-			 */
-			if (!dst_metric_locked(dst, RTAX_CWND))
-				dst_metric_set(dst, RTAX_CWND,
-					       (dst_metric(dst, RTAX_CWND) +
-						tp->snd_ssthresh) >> 1);
-			if (dst_metric(dst, RTAX_SSTHRESH) &&
-			    !dst_metric_locked(dst, RTAX_SSTHRESH) &&
-			    tp->snd_ssthresh > dst_metric(dst, RTAX_SSTHRESH))
-				dst_metric_set(dst, RTAX_SSTHRESH, tp->snd_ssthresh);
-		}
-
-		if (!dst_metric_locked(dst, RTAX_REORDERING)) {
-			if (dst_metric(dst, RTAX_REORDERING) < tp->reordering &&
-			    tp->reordering != sysctl_tcp_reordering)
-				dst_metric_set(dst, RTAX_REORDERING, tp->reordering);
-		}
-	}
-}
-
 __u32 tcp_init_cwnd(const struct tcp_sock *tp, const struct dst_entry *dst)
 {
 	__u32 cwnd = (dst ? dst_metric(dst, RTAX_INITCWND) : 0);
@@ -867,7 +763,7 @@ void tcp_enter_cwr(struct sock *sk, const int set_ssthresh)
  * Packet counting of FACK is based on in-order assumptions, therefore TCP
  * disables it when reordering is detected
  */
-static void tcp_disable_fack(struct tcp_sock *tp)
+void tcp_disable_fack(struct tcp_sock *tp)
 {
 	/* RFC3517 uses different metric in lost marker => reset on change */
 	if (tcp_is_fack(tp))
@@ -881,86 +777,6 @@ static void tcp_dsack_seen(struct tcp_sock *tp)
 	tp->rx_opt.sack_ok |= TCP_DSACK_SEEN;
 }
 
-/* Initialize metrics on socket. */
-
-static void tcp_init_metrics(struct sock *sk)
-{
-	struct tcp_sock *tp = tcp_sk(sk);
-	struct dst_entry *dst = __sk_dst_get(sk);
-
-	if (dst == NULL)
-		goto reset;
-
-	dst_confirm(dst);
-
-	if (dst_metric_locked(dst, RTAX_CWND))
-		tp->snd_cwnd_clamp = dst_metric(dst, RTAX_CWND);
-	if (dst_metric(dst, RTAX_SSTHRESH)) {
-		tp->snd_ssthresh = dst_metric(dst, RTAX_SSTHRESH);
-		if (tp->snd_ssthresh > tp->snd_cwnd_clamp)
-			tp->snd_ssthresh = tp->snd_cwnd_clamp;
-	} else {
-		/* ssthresh may have been reduced unnecessarily during.
-		 * 3WHS. Restore it back to its initial default.
-		 */
-		tp->snd_ssthresh = TCP_INFINITE_SSTHRESH;
-	}
-	if (dst_metric(dst, RTAX_REORDERING) &&
-	    tp->reordering != dst_metric(dst, RTAX_REORDERING)) {
-		tcp_disable_fack(tp);
-		tcp_disable_early_retrans(tp);
-		tp->reordering = dst_metric(dst, RTAX_REORDERING);
-	}
-
-	if (dst_metric(dst, RTAX_RTT) == 0 || tp->srtt == 0)
-		goto reset;
-
-	/* Initial rtt is determined from SYN,SYN-ACK.
-	 * The segment is small and rtt may appear much
-	 * less than real one. Use per-dst memory
-	 * to make it more realistic.
-	 *
-	 * A bit of theory. RTT is time passed after "normal" sized packet
-	 * is sent until it is ACKed. In normal circumstances sending small
-	 * packets force peer to delay ACKs and calculation is correct too.
-	 * The algorithm is adaptive and, provided we follow specs, it
-	 * NEVER underestimate RTT. BUT! If peer tries to make some clever
-	 * tricks sort of "quick acks" for time long enough to decrease RTT
-	 * to low value, and then abruptly stops to do it and starts to delay
-	 * ACKs, wait for troubles.
-	 */
-	if (dst_metric_rtt(dst, RTAX_RTT) > tp->srtt) {
-		tp->srtt = dst_metric_rtt(dst, RTAX_RTT);
-		tp->rtt_seq = tp->snd_nxt;
-	}
-	if (dst_metric_rtt(dst, RTAX_RTTVAR) > tp->mdev) {
-		tp->mdev = dst_metric_rtt(dst, RTAX_RTTVAR);
-		tp->mdev_max = tp->rttvar = max(tp->mdev, tcp_rto_min(sk));
-	}
-	tcp_set_rto(sk);
-reset:
-	if (tp->srtt == 0) {
-		/* RFC6298: 5.7 We've failed to get a valid RTT sample from
-		 * 3WHS. This is most likely due to retransmission,
-		 * including spurious one. Reset the RTO back to 3secs
-		 * from the more aggressive 1sec to avoid more spurious
-		 * retransmission.
-		 */
-		tp->mdev = tp->mdev_max = tp->rttvar = TCP_TIMEOUT_FALLBACK;
-		inet_csk(sk)->icsk_rto = TCP_TIMEOUT_FALLBACK;
-	}
-	/* Cut cwnd down to 1 per RFC5681 if SYN or SYN-ACK has been
-	 * retransmitted. In light of RFC6298 more aggressive 1sec
-	 * initRTO, we only reset cwnd when more than 1 SYN/SYN-ACK
-	 * retransmission has occurred.
-	 */
-	if (tp->total_retrans > 1)
-		tp->snd_cwnd = 1;
-	else
-		tp->snd_cwnd = tcp_init_cwnd(tp, dst);
-	tp->snd_cwnd_stamp = tcp_time_stamp;
-}
-
 static void tcp_update_reordering(struct sock *sk, const int metric,
 				  const int ts)
 {

net/ipv4/tcp_ipv4.c

@@ -209,22 +209,8 @@ int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
 	}
 
 	if (tcp_death_row.sysctl_tw_recycle &&
-	    !tp->rx_opt.ts_recent_stamp && fl4->daddr == daddr) {
-		struct inet_peer *peer = rt_get_peer(rt, fl4->daddr);
-		/*
-		 * VJ's idea. We save last timestamp seen from
-		 * the destination in peer table, when entering state
-		 * TIME-WAIT * and initialize rx_opt.ts_recent from it,
-		 * when trying new connection.
-		 */
-		if (peer) {
-			inet_peer_refcheck(peer);
-			if ((u32)get_seconds() - peer->tcp_ts_stamp <= TCP_PAWS_MSL) {
-				tp->rx_opt.ts_recent_stamp = peer->tcp_ts_stamp;
-				tp->rx_opt.ts_recent = peer->tcp_ts;
-			}
-		}
-	}
+	    !tp->rx_opt.ts_recent_stamp && fl4->daddr == daddr)
+		tcp_fetch_timewait_stamp(sk, &rt->dst);
 
 	inet->inet_dport = usin->sin_port;
 	inet->inet_daddr = daddr;
@@ -1375,7 +1361,6 @@ int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
 		isn = cookie_v4_init_sequence(sk, skb, &req->mss);
 		req->cookie_ts = tmp_opt.tstamp_ok;
 	} else if (!isn) {
-		struct inet_peer *peer = NULL;
 		struct flowi4 fl4;
 
 		/* VJ's idea. We save last timestamp seen
@@ -1390,12 +1375,8 @@ int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
 		if (tmp_opt.saw_tstamp &&
 		    tcp_death_row.sysctl_tw_recycle &&
 		    (dst = inet_csk_route_req(sk, &fl4, req, want_cookie)) != NULL &&
-		    fl4.daddr == saddr &&
-		    (peer = rt_get_peer((struct rtable *)dst, fl4.daddr)) != NULL) {
-			inet_peer_refcheck(peer);
-			if ((u32)get_seconds() - peer->tcp_ts_stamp < TCP_PAWS_MSL &&
-			    (s32)(peer->tcp_ts - req->ts_recent) >
-							TCP_PAWS_WINDOW) {
+		    fl4.daddr == saddr) {
+			if (!tcp_peer_is_proven(req, dst, true)) {
 				NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_PAWSPASSIVEREJECTED);
 				goto drop_and_release;
 			}
@@ -1404,8 +1385,7 @@ int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
 		else if (!sysctl_tcp_syncookies &&
 			 (sysctl_max_syn_backlog - inet_csk_reqsk_queue_len(sk) <
 			  (sysctl_max_syn_backlog >> 2)) &&
-			 (!peer || !peer->tcp_ts_stamp) &&
-			 (!dst || !dst_metric(dst, RTAX_RTT))) {
+			 !tcp_peer_is_proven(req, dst, false)) {
 			/* Without syncookies last quarter of
 			 * backlog is filled with destinations,
 			 * proven to be alive.
@@ -1867,21 +1847,6 @@ int tcp_v4_rcv(struct sk_buff *skb)
 	goto discard_it;
 }
 
-struct inet_peer *tcp_v4_get_peer(struct sock *sk)
-{
-	struct rtable *rt = (struct rtable *) __sk_dst_get(sk);
-	struct inet_sock *inet = inet_sk(sk);
-
-	/* If we don't have a valid cached route, or we're doing IP
-	 * options which make the IPv4 header destination address
-	 * different from our peer's, do not bother with this.
-	 */
-	if (!rt || inet->cork.fl.u.ip4.daddr != inet->inet_daddr)
-		return NULL;
-	return rt_get_peer_create(rt, inet->inet_daddr);
-}
-EXPORT_SYMBOL(tcp_v4_get_peer);
-
 static struct timewait_sock_ops tcp_timewait_sock_ops = {
 	.twsk_obj_size	= sizeof(struct tcp_timewait_sock),
 	.twsk_unique	= tcp_twsk_unique,
@@ -1894,7 +1859,6 @@ const struct inet_connection_sock_af_ops ipv4_specific = {
 	.rebuild_header	   = inet_sk_rebuild_header,
 	.conn_request	   = tcp_v4_conn_request,
 	.syn_recv_sock	   = tcp_v4_syn_recv_sock,
-	.get_peer	   = tcp_v4_get_peer,
 	.net_header_len	   = sizeof(struct iphdr),
 	.setsockopt	   = ip_setsockopt,
 	.getsockopt	   = ip_getsockopt,

net/ipv4/tcp_minisocks.c

@@ -49,52 +49,6 @@ struct inet_timewait_death_row tcp_death_row = {
 };
 EXPORT_SYMBOL_GPL(tcp_death_row);
 
-/* VJ's idea. Save last timestamp seen from this destination
- * and hold it at least for normal timewait interval to use for duplicate
- * segment detection in subsequent connections, before they enter synchronized
- * state.
- */
-
-static bool tcp_remember_stamp(struct sock *sk)
-{
-	const struct inet_connection_sock *icsk = inet_csk(sk);
-	struct tcp_sock *tp = tcp_sk(sk);
-	struct inet_peer *peer;
-
-	peer = icsk->icsk_af_ops->get_peer(sk);
-	if (peer) {
-		if ((s32)(peer->tcp_ts - tp->rx_opt.ts_recent) <= 0 ||
-		    ((u32)get_seconds() - peer->tcp_ts_stamp > TCP_PAWS_MSL &&
-		     peer->tcp_ts_stamp <= (u32)tp->rx_opt.ts_recent_stamp)) {
-			peer->tcp_ts_stamp = (u32)tp->rx_opt.ts_recent_stamp;
-			peer->tcp_ts = tp->rx_opt.ts_recent;
-		}
-		return true;
-	}
-
-	return false;
-}
-
-static bool tcp_tw_remember_stamp(struct inet_timewait_sock *tw)
-{
-	const struct tcp_timewait_sock *tcptw;
-	struct sock *sk = (struct sock *) tw;
-	struct inet_peer *peer;
-
-	tcptw = tcp_twsk(sk);
-	peer = tcptw->tw_peer;
-	if (peer) {
-		if ((s32)(peer->tcp_ts - tcptw->tw_ts_recent) <= 0 ||
-		    ((u32)get_seconds() - peer->tcp_ts_stamp > TCP_PAWS_MSL &&
-		     peer->tcp_ts_stamp <= (u32)tcptw->tw_ts_recent_stamp)) {
-			peer->tcp_ts_stamp = (u32)tcptw->tw_ts_recent_stamp;
-			peer->tcp_ts	   = tcptw->tw_ts_recent;
-		}
-		return true;
-	}
-	return false;
-}
-
 static bool tcp_in_window(u32 seq, u32 end_seq, u32 s_win, u32 e_win)
 {
 	if (seq == s_win)
@@ -313,12 +267,9 @@ void tcp_time_wait(struct sock *sk, int state, int timeo)
 	const struct inet_connection_sock *icsk = inet_csk(sk);
 	const struct tcp_sock *tp = tcp_sk(sk);
 	bool recycle_ok = false;
-	bool recycle_on = false;
 
-	if (tcp_death_row.sysctl_tw_recycle && tp->rx_opt.ts_recent_stamp) {
+	if (tcp_death_row.sysctl_tw_recycle && tp->rx_opt.ts_recent_stamp)
 		recycle_ok = tcp_remember_stamp(sk);
-		recycle_on = true;
-	}
 
 	if (tcp_death_row.tw_count < tcp_death_row.sysctl_max_tw_buckets)
 		tw = inet_twsk_alloc(sk, state);
@@ -327,7 +278,6 @@ void tcp_time_wait(struct sock *sk, int state, int timeo)
 		struct tcp_timewait_sock *tcptw = tcp_twsk((struct sock *)tw);
 		const int rto = (icsk->icsk_rto << 2) - (icsk->icsk_rto >> 1);
 		struct inet_sock *inet = inet_sk(sk);
-		struct inet_peer *peer = NULL;
 
 		tw->tw_transparent	= inet->transparent;
 		tw->tw_rcv_wscale	= tp->rx_opt.rcv_wscale;
@@ -351,12 +301,6 @@ void tcp_time_wait(struct sock *sk, int state, int timeo)
 		}
 #endif
 
-		if (recycle_on)
-			peer = icsk->icsk_af_ops->get_peer(sk);
-		tcptw->tw_peer = peer;
-		if (peer)
-			atomic_inc(&peer->refcnt);
-
 #ifdef CONFIG_TCP_MD5SIG
 		/*
 		 * The timewait bucket does not have the key DB from the
@@ -408,11 +352,9 @@ void tcp_time_wait(struct sock *sk, int state, int timeo)
 
 void tcp_twsk_destructor(struct sock *sk)
 {
+#ifdef CONFIG_TCP_MD5SIG
 	struct tcp_timewait_sock *twsk = tcp_twsk(sk);
 
-	if (twsk->tw_peer)
-		inet_putpeer(twsk->tw_peer);
-#ifdef CONFIG_TCP_MD5SIG
 	if (twsk->tw_md5_key) {
 		tcp_free_md5sig_pool();
 		kfree_rcu(twsk->tw_md5_key, rcu);

net/ipv4/xfrm4_policy.c

@@ -90,8 +90,6 @@ static int xfrm4_fill_dst(struct xfrm_dst *xdst, struct net_device *dev,
 	xdst->u.dst.dev = dev;
 	dev_hold(dev);
 
-	rt_transfer_peer(&xdst->u.rt, rt);
-
 	/* Sheit... I remember I did this right. Apparently,
 	 * it was magically lost, so this code needs audit */
 	xdst->u.rt.rt_flags = rt->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST |
@@ -100,6 +98,7 @@ static int xfrm4_fill_dst(struct xfrm_dst *xdst, struct net_device *dev,
 	xdst->u.rt.rt_src = rt->rt_src;
 	xdst->u.rt.rt_dst = rt->rt_dst;
 	xdst->u.rt.rt_gateway = rt->rt_gateway;
+	xdst->u.rt.rt_pmtu = rt->rt_pmtu;
 
 	return 0;
 }
@@ -209,11 +208,6 @@ static void xfrm4_dst_destroy(struct dst_entry *dst)
 
 	dst_destroy_metrics_generic(dst);
 
-	if (rt_has_peer(&xdst->u.rt)) {
-		struct inet_peer *peer = rt_peer_ptr(&xdst->u.rt);
-		inet_putpeer(peer);
-	}
-
 	xfrm_dst_destroy(xdst);
 }
 

net/ipv6/icmp.c

@@ -194,8 +194,10 @@ static inline bool icmpv6_xrlim_allow(struct sock *sk, u8 type,
 		if (rt->rt6i_dst.plen < 128)
 			tmo >>= ((128 - rt->rt6i_dst.plen)>>5);
 
-		peer = rt6_get_peer_create(rt);
+		peer = inet_getpeer_v6(net->ipv6.peers, &rt->rt6i_dst.addr, 1);
 		res = inet_peer_xrlim_allow(peer, tmo);
+		if (peer)
+			inet_putpeer(peer);
 	}
 	dst_release(dst);
 	return res;

net/ipv6/ip6_output.c

@@ -466,13 +466,15 @@ int ip6_forward(struct sk_buff *skb)
 		else
 			target = &hdr->daddr;
 
-		peer = rt6_get_peer_create(rt);
+		peer = inet_getpeer_v6(net->ipv6.peers, &rt->rt6i_dst.addr, 1);
 
 		/* Limit redirects both by destination (here)
 		   and by source (inside ndisc_send_redirect)
 		 */
 		if (inet_peer_xrlim_allow(peer, 1*HZ))
 			ndisc_send_redirect(skb, target);
+		if (peer)
+			inet_putpeer(peer);
 	} else {
 		int addrtype = ipv6_addr_type(&hdr->saddr);
 
@@ -592,10 +594,14 @@ void ipv6_select_ident(struct frag_hdr *fhdr, struct rt6_info *rt)
 	int old, new;
 
 	if (rt && !(rt->dst.flags & DST_NOPEER)) {
-		struct inet_peer *peer = rt6_get_peer_create(rt);
+		struct inet_peer *peer;
+		struct net *net;
 
+		net = dev_net(rt->dst.dev);
+		peer = inet_getpeer_v6(net->ipv6.peers, &rt->rt6i_dst.addr, 1);
 		if (peer) {
 			fhdr->identification = htonl(inet_getid(peer, 0));
+			inet_putpeer(peer);
 			return;
 		}
 	}

net/ipv6/ndisc.c

@@ -1486,6 +1486,7 @@ void ndisc_send_redirect(struct sk_buff *skb, const struct in6_addr *target)
 	int rd_len;
 	int err;
 	u8 ha_buf[MAX_ADDR_LEN], *ha = NULL;
+	bool ret;
 
 	if (ipv6_get_lladdr(dev, &saddr_buf, IFA_F_TENTATIVE)) {
 		ND_PRINTK(2, warn, "Redirect: no link-local address on %s\n",
@@ -1519,8 +1520,11 @@ void ndisc_send_redirect(struct sk_buff *skb, const struct in6_addr *target)
 			  "Redirect: destination is not a neighbour\n");
 		goto release;
 	}
-	peer = rt6_get_peer_create(rt);
-	if (!inet_peer_xrlim_allow(peer, 1*HZ))
+	peer = inet_getpeer_v6(net->ipv6.peers, &rt->rt6i_dst.addr, 1);
+	ret = inet_peer_xrlim_allow(peer, 1*HZ);
+	if (peer)
+		inet_putpeer(peer);
+	if (!ret)
 		goto release;
 
 	if (dev->addr_len) {

net/ipv6/route.c

@@ -1093,7 +1093,7 @@ void ip6_update_pmtu(struct sk_buff *skb, struct net *net, __be32 mtu,
 	memset(&fl6, 0, sizeof(fl6));
 	fl6.flowi6_oif = oif;
 	fl6.flowi6_mark = mark;
-	fl6.flowi6_flags = FLOWI_FLAG_PRECOW_METRICS;
+	fl6.flowi6_flags = 0;
 	fl6.daddr = iph->daddr;
 	fl6.saddr = iph->saddr;
 	fl6.flowlabel = (*(__be32 *) iph) & IPV6_FLOWINFO_MASK;
@@ -2348,13 +2348,11 @@ static int rt6_fill_node(struct net *net,
 			 int iif, int type, u32 pid, u32 seq,
 			 int prefix, int nowait, unsigned int flags)
 {
-	const struct inet_peer *peer;
 	struct rtmsg *rtm;
 	struct nlmsghdr *nlh;
 	long expires;
 	u32 table;
 	struct neighbour *n;
-	u32 ts, tsage;
 
 	if (prefix) {	/* user wants prefix routes only */
 		if (!(rt->rt6i_flags & RTF_PREFIX_RT)) {
@@ -2473,17 +2471,7 @@ static int rt6_fill_node(struct net *net,
 	else
 		expires = INT_MAX;
 
-	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;
-		tsage = get_seconds() - peer->tcp_ts_stamp;
-	}
-
-	if (rtnl_put_cacheinfo(skb, &rt->dst, 0, ts, tsage,
-			       expires, rt->dst.error) < 0)
+	if (rtnl_put_cacheinfo(skb, &rt->dst, 0, expires, rt->dst.error) < 0)
 		goto nla_put_failure;
 
 	return nlmsg_end(skb, nlh);

net/ipv6/tcp_ipv6.c

@@ -277,22 +277,8 @@ static int tcp_v6_connect(struct sock *sk, struct sockaddr *uaddr,
 	rt = (struct rt6_info *) dst;
 	if (tcp_death_row.sysctl_tw_recycle &&
 	    !tp->rx_opt.ts_recent_stamp &&
-	    ipv6_addr_equal(&rt->rt6i_dst.addr, &np->daddr)) {
-		struct inet_peer *peer = rt6_get_peer(rt);
-		/*
-		 * VJ's idea. We save last timestamp seen from
-		 * the destination in peer table, when entering state
-		 * TIME-WAIT * and initialize rx_opt.ts_recent from it,
-		 * when trying new connection.
-		 */
-		if (peer) {
-			inet_peer_refcheck(peer);
-			if ((u32)get_seconds() - peer->tcp_ts_stamp <= TCP_PAWS_MSL) {
-				tp->rx_opt.ts_recent_stamp = peer->tcp_ts_stamp;
-				tp->rx_opt.ts_recent = peer->tcp_ts;
-			}
-		}
-	}
+	    ipv6_addr_equal(&rt->rt6i_dst.addr, &np->daddr))
+		tcp_fetch_timewait_stamp(sk, dst);
 
 	icsk->icsk_ext_hdr_len = 0;
 	if (np->opt)
@@ -1134,8 +1120,6 @@ static int tcp_v6_conn_request(struct sock *sk, struct sk_buff *skb)
 		treq->iif = inet6_iif(skb);
 
 	if (!isn) {
-		struct inet_peer *peer = NULL;
-
 		if (ipv6_opt_accepted(sk, skb) ||
 		    np->rxopt.bits.rxinfo || np->rxopt.bits.rxoinfo ||
 		    np->rxopt.bits.rxhlim || np->rxopt.bits.rxohlim) {
@@ -1160,14 +1144,8 @@ static int tcp_v6_conn_request(struct sock *sk, struct sk_buff *skb)
 		 */
 		if (tmp_opt.saw_tstamp &&
 		    tcp_death_row.sysctl_tw_recycle &&
-		    (dst = inet6_csk_route_req(sk, &fl6, req)) != NULL &&
-		    (peer = rt6_get_peer((struct rt6_info *)dst)) != NULL &&
-		    ipv6_addr_equal((struct in6_addr *)peer->daddr.addr.a6,
-				    &treq->rmt_addr)) {
-			inet_peer_refcheck(peer);
-			if ((u32)get_seconds() - peer->tcp_ts_stamp < TCP_PAWS_MSL &&
-			    (s32)(peer->tcp_ts - req->ts_recent) >
-							TCP_PAWS_WINDOW) {
+		    (dst = inet6_csk_route_req(sk, &fl6, req)) != NULL) {
+			if (!tcp_peer_is_proven(req, dst, true)) {
 				NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_PAWSPASSIVEREJECTED);
 				goto drop_and_release;
 			}
@@ -1176,8 +1154,7 @@ static int tcp_v6_conn_request(struct sock *sk, struct sk_buff *skb)
 		else if (!sysctl_tcp_syncookies &&
 			 (sysctl_max_syn_backlog - inet_csk_reqsk_queue_len(sk) <
 			  (sysctl_max_syn_backlog >> 2)) &&
-			 (!peer || !peer->tcp_ts_stamp) &&
-			 (!dst || !dst_metric(dst, RTAX_RTT))) {
+			 !tcp_peer_is_proven(req, dst, false)) {
 			/* Without syncookies last quarter of
 			 * backlog is filled with destinations,
 			 * proven to be alive.
@@ -1712,20 +1689,6 @@ static int tcp_v6_rcv(struct sk_buff *skb)
 	goto discard_it;
 }
 
-static struct inet_peer *tcp_v6_get_peer(struct sock *sk)
-{
-	struct rt6_info *rt = (struct rt6_info *) __sk_dst_get(sk);
-	struct ipv6_pinfo *np = inet6_sk(sk);
-
-	/* If we don't have a valid cached route, or we're doing IP
-	 * options which make the IPv6 header destination address
-	 * different from our peer's, do not bother with this.
-	 */
-	if (!rt || !ipv6_addr_equal(&np->daddr, &rt->rt6i_dst.addr))
-		return NULL;
-	return rt6_get_peer_create(rt);
-}
-
 static struct timewait_sock_ops tcp6_timewait_sock_ops = {
 	.twsk_obj_size	= sizeof(struct tcp6_timewait_sock),
 	.twsk_unique	= tcp_twsk_unique,
@@ -1738,7 +1701,6 @@ static const struct inet_connection_sock_af_ops ipv6_specific = {
 	.rebuild_header	   = inet6_sk_rebuild_header,
 	.conn_request	   = tcp_v6_conn_request,
 	.syn_recv_sock	   = tcp_v6_syn_recv_sock,
-	.get_peer	   = tcp_v6_get_peer,
 	.net_header_len	   = sizeof(struct ipv6hdr),
 	.net_frag_header_len = sizeof(struct frag_hdr),
 	.setsockopt	   = ipv6_setsockopt,
@@ -1770,7 +1732,6 @@ static const struct inet_connection_sock_af_ops ipv6_mapped = {
 	.rebuild_header	   = inet_sk_rebuild_header,
 	.conn_request	   = tcp_v6_conn_request,
 	.syn_recv_sock	   = tcp_v6_syn_recv_sock,
-	.get_peer	   = tcp_v4_get_peer,
 	.net_header_len	   = sizeof(struct iphdr),
 	.setsockopt	   = ipv6_setsockopt,
 	.getsockopt	   = ipv6_getsockopt,