1 files changed, 171 insertions, 124 deletions
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 4811727b8a02..e1f952fbac48 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -102,6 +102,7 @@ int sysctl_tcp_max_orphans __read_mostly = NR_FILE;
 #define FLAG_NO_CHALLENGE_ACK	0x8000 /* do not call tcp_send_challenge_ack()	*/
 #define FLAG_ACK_MAYBE_DELAYED	0x10000 /* Likely a delayed ACK */
 #define FLAG_DSACK_TLP		0x20000 /* DSACK for tail loss probe */
+#define FLAG_TS_PROGRESS	0x40000 /* Positive timestamp delta */
 
 #define FLAG_ACKED		(FLAG_DATA_ACKED|FLAG_SYN_ACKED)
 #define FLAG_NOT_DUP		(FLAG_DATA|FLAG_WIN_UPDATE|FLAG_ACKED)
@@ -118,18 +119,18 @@ int sysctl_tcp_max_orphans __read_mostly = NR_FILE;
 #if IS_ENABLED(CONFIG_TLS_DEVICE)
 static DEFINE_STATIC_KEY_DEFERRED_FALSE(clean_acked_data_enabled, HZ);
 
-void clean_acked_data_enable(struct inet_connection_sock *icsk,
+void clean_acked_data_enable(struct tcp_sock *tp,
 			     void (*cad)(struct sock *sk, u32 ack_seq))
 {
-	icsk->icsk_clean_acked = cad;
+	tp->tcp_clean_acked = cad;
 	static_branch_deferred_inc(&clean_acked_data_enabled);
 }
 EXPORT_SYMBOL_GPL(clean_acked_data_enable);
 
-void clean_acked_data_disable(struct inet_connection_sock *icsk)
+void clean_acked_data_disable(struct tcp_sock *tp)
 {
 	static_branch_slow_dec_deferred(&clean_acked_data_enabled);
-	icsk->icsk_clean_acked = NULL;
+	tp->tcp_clean_acked = NULL;
 }
 EXPORT_SYMBOL_GPL(clean_acked_data_disable);
 
@@ -169,6 +170,7 @@ static void bpf_skops_parse_hdr(struct sock *sk, struct sk_buff *skb)
 	memset(&sock_ops, 0, offsetof(struct bpf_sock_ops_kern, temp));
 	sock_ops.op = BPF_SOCK_OPS_PARSE_HDR_OPT_CB;
 	sock_ops.is_fullsock = 1;
+	sock_ops.is_locked_tcp_sock = 1;
 	sock_ops.sk = sk;
 	bpf_skops_init_skb(&sock_ops, skb, tcp_hdrlen(skb));
 
@@ -185,6 +187,7 @@ static void bpf_skops_established(struct sock *sk, int bpf_op,
 	memset(&sock_ops, 0, offsetof(struct bpf_sock_ops_kern, temp));
 	sock_ops.op = bpf_op;
 	sock_ops.is_fullsock = 1;
+	sock_ops.is_locked_tcp_sock = 1;
 	sock_ops.sk = sk;
 	/* sk with TCP_REPAIR_ON does not have skb in tcp_finish_connect */
 	if (skb)
@@ -243,9 +246,15 @@ static void tcp_measure_rcv_mss(struct sock *sk, const struct sk_buff *skb)
 			do_div(val, skb->truesize);
 			tcp_sk(sk)->scaling_ratio = val ? val : 1;
 
-			if (old_ratio != tcp_sk(sk)->scaling_ratio)
-				WRITE_ONCE(tcp_sk(sk)->window_clamp,
-					   tcp_win_from_space(sk, sk->sk_rcvbuf));
+			if (old_ratio != tcp_sk(sk)->scaling_ratio) {
+				struct tcp_sock *tp = tcp_sk(sk);
+
+				val = tcp_win_from_space(sk, sk->sk_rcvbuf);
+				tcp_set_window_clamp(sk, val);
+
+				if (tp->window_clamp < tp->rcvq_space.space)
+					tp->rcvq_space.space = tp->window_clamp;
+			}
 		}
 		icsk->icsk_ack.rcv_mss = min_t(unsigned int, len,
 					       tcp_sk(sk)->advmss);
@@ -325,15 +334,14 @@ static void tcp_enter_quickack_mode(struct sock *sk, unsigned int max_quickacks)
 static bool tcp_in_quickack_mode(struct sock *sk)
 {
 	const struct inet_connection_sock *icsk = inet_csk(sk);
-	const struct dst_entry *dst = __sk_dst_get(sk);
 
-	return (dst && dst_metric(dst, RTAX_QUICKACK)) ||
+	return icsk->icsk_ack.dst_quick_ack ||
 		(icsk->icsk_ack.quick && !inet_csk_in_pingpong_mode(sk));
 }
 
 static void tcp_ecn_queue_cwr(struct tcp_sock *tp)
 {
-	if (tp->ecn_flags & TCP_ECN_OK)
+	if (tcp_ecn_mode_rfc3168(tp))
 		tp->ecn_flags |= TCP_ECN_QUEUE_CWR;
 }
 
@@ -356,10 +364,13 @@ static void tcp_ecn_withdraw_cwr(struct tcp_sock *tp)
 	tp->ecn_flags &= ~TCP_ECN_QUEUE_CWR;
 }
 
-static void __tcp_ecn_check_ce(struct sock *sk, const struct sk_buff *skb)
+static void tcp_data_ecn_check(struct sock *sk, const struct sk_buff *skb)
 {
 	struct tcp_sock *tp = tcp_sk(sk);
 
+	if (tcp_ecn_disabled(tp))
+		return;
+
 	switch (TCP_SKB_CB(skb)->ip_dsfield & INET_ECN_MASK) {
 	case INET_ECN_NOT_ECT:
 		/* Funny extension: if ECT is not set on a segment,
@@ -388,31 +399,39 @@ static void __tcp_ecn_check_ce(struct sock *sk, const struct sk_buff *skb)
 	}
 }
 
-static void tcp_ecn_check_ce(struct sock *sk, const struct sk_buff *skb)
-{
-	if (tcp_sk(sk)->ecn_flags & TCP_ECN_OK)
-		__tcp_ecn_check_ce(sk, skb);
-}
-
 static void tcp_ecn_rcv_synack(struct tcp_sock *tp, const struct tcphdr *th)
 {
-	if ((tp->ecn_flags & TCP_ECN_OK) && (!th->ece || th->cwr))
-		tp->ecn_flags &= ~TCP_ECN_OK;
+	if (tcp_ecn_mode_rfc3168(tp) && (!th->ece || th->cwr))
+		tcp_ecn_mode_set(tp, TCP_ECN_DISABLED);
 }
 
 static void tcp_ecn_rcv_syn(struct tcp_sock *tp, const struct tcphdr *th)
 {
-	if ((tp->ecn_flags & TCP_ECN_OK) && (!th->ece || !th->cwr))
-		tp->ecn_flags &= ~TCP_ECN_OK;
+	if (tcp_ecn_mode_rfc3168(tp) && (!th->ece || !th->cwr))
+		tcp_ecn_mode_set(tp, TCP_ECN_DISABLED);
 }
 
 static bool tcp_ecn_rcv_ecn_echo(const struct tcp_sock *tp, const struct tcphdr *th)
 {
-	if (th->ece && !th->syn && (tp->ecn_flags & TCP_ECN_OK))
+	if (th->ece && !th->syn && tcp_ecn_mode_rfc3168(tp))
 		return true;
 	return false;
 }
 
+static void tcp_count_delivered_ce(struct tcp_sock *tp, u32 ecn_count)
+{
+	tp->delivered_ce += ecn_count;
+}
+
+/* Updates the delivered and delivered_ce counts */
+static void tcp_count_delivered(struct tcp_sock *tp, u32 delivered,
+				bool ece_ack)
+{
+	tp->delivered += delivered;
+	if (ece_ack)
+		tcp_count_delivered_ce(tp, delivered);
+}
+
 /* Buffer size and advertised window tuning.
  *
  * 1. Tuning sk->sk_sndbuf, when connection enters established state.
@@ -630,7 +649,7 @@ void tcp_initialize_rcv_mss(struct sock *sk)
 
 	inet_csk(sk)->icsk_ack.rcv_mss = hint;
 }
-EXPORT_SYMBOL(tcp_initialize_rcv_mss);
+EXPORT_IPV6_MOD(tcp_initialize_rcv_mss);
 
 /* Receiver "autotuning" code.
  *
@@ -851,7 +870,7 @@ static void tcp_event_data_recv(struct sock *sk, struct sk_buff *skb)
 	icsk->icsk_ack.lrcvtime = now;
 	tcp_save_lrcv_flowlabel(sk, skb);
 
-	tcp_ecn_check_ce(sk, skb);
+	tcp_data_ecn_check(sk, skb);
 
 	if (skb->len >= 128)
 		tcp_grow_window(sk, skb, true);
@@ -1148,15 +1167,6 @@ void tcp_mark_skb_lost(struct sock *sk, struct sk_buff *skb)
 	}
 }
 
-/* Updates the delivered and delivered_ce counts */
-static void tcp_count_delivered(struct tcp_sock *tp, u32 delivered,
-				bool ece_ack)
-{
-	tp->delivered += delivered;
-	if (ece_ack)
-		tp->delivered_ce += delivered;
-}
-
 /* This procedure tags the retransmission queue when SACKs arrive.
  *
  * We have three tag bits: SACKED(S), RETRANS(R) and LOST(L).
@@ -2252,8 +2262,7 @@ static bool tcp_check_sack_reneging(struct sock *sk, int *ack_flag)
 		unsigned long delay = max(usecs_to_jiffies(tp->srtt_us >> 4),
 					  msecs_to_jiffies(10));
 
-		inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
-					  delay, TCP_RTO_MAX);
+		tcp_reset_xmit_timer(sk, ICSK_TIME_RETRANS, delay, false);
 		*ack_flag &= ~FLAG_SET_XMIT_TIMER;
 		return true;
 	}
@@ -2710,6 +2719,8 @@ void tcp_cwnd_reduction(struct sock *sk, int newly_acked_sacked, int newly_lost,
 	if (newly_acked_sacked <= 0 || WARN_ON_ONCE(!tp->prior_cwnd))
 		return;
 
+	trace_tcp_cwnd_reduction_tp(sk, newly_acked_sacked, newly_lost, flag);
+
 	tp->prr_delivered += newly_acked_sacked;
 	if (delta < 0) {
 		u64 dividend = (u64)tp->snd_ssthresh * tp->prr_delivered +
@@ -2892,7 +2903,7 @@ void tcp_simple_retransmit(struct sock *sk)
 	 */
 	tcp_non_congestion_loss_retransmit(sk);
 }
-EXPORT_SYMBOL(tcp_simple_retransmit);
+EXPORT_IPV6_MOD(tcp_simple_retransmit);
 
 void tcp_enter_recovery(struct sock *sk, bool ece_ack)
 {
@@ -3282,8 +3293,7 @@ void tcp_rearm_rto(struct sock *sk)
 			 */
 			rto = usecs_to_jiffies(max_t(int, delta_us, 1));
 		}
-		tcp_reset_xmit_timer(sk, ICSK_TIME_RETRANS, rto,
-				     TCP_RTO_MAX);
+		tcp_reset_xmit_timer(sk, ICSK_TIME_RETRANS, rto, true);
 	}
 }
 
@@ -3560,10 +3570,10 @@ static void tcp_ack_probe(struct sock *sk)
 		 * This function is not for random using!
 		 */
 	} else {
-		unsigned long when = tcp_probe0_when(sk, TCP_RTO_MAX);
+		unsigned long when = tcp_probe0_when(sk, tcp_rto_max(sk));
 
 		when = tcp_clamp_probe0_to_user_timeout(sk, when);
-		tcp_reset_xmit_timer(sk, ICSK_TIME_PROBE0, when, TCP_RTO_MAX);
+		tcp_reset_xmit_timer(sk, ICSK_TIME_PROBE0, when, true);
 	}
 }
 
@@ -3808,8 +3818,16 @@ static void tcp_store_ts_recent(struct tcp_sock *tp)
 	tp->rx_opt.ts_recent_stamp = ktime_get_seconds();
 }
 
-static void tcp_replace_ts_recent(struct tcp_sock *tp, u32 seq)
+static int __tcp_replace_ts_recent(struct tcp_sock *tp, s32 tstamp_delta)
+{
+	tcp_store_ts_recent(tp);
+	return tstamp_delta > 0 ? FLAG_TS_PROGRESS : 0;
+}
+
+static int tcp_replace_ts_recent(struct tcp_sock *tp, u32 seq)
 {
+	s32 delta;
+
 	if (tp->rx_opt.saw_tstamp && !after(seq, tp->rcv_wup)) {
 		/* PAWS bug workaround wrt. ACK frames, the PAWS discard
 		 * extra check below makes sure this can only happen
@@ -3818,9 +3836,13 @@ static void tcp_replace_ts_recent(struct tcp_sock *tp, u32 seq)
 		 * Not only, also it occurs for expired timestamps.
 		 */
 
-		if (tcp_paws_check(&tp->rx_opt, 0))
-			tcp_store_ts_recent(tp);
+		if (tcp_paws_check(&tp->rx_opt, 0)) {
+			delta = tp->rx_opt.rcv_tsval - tp->rx_opt.ts_recent;
+			return __tcp_replace_ts_recent(tp, delta);
+		}
 	}
+
+	return 0;
 }
 
 /* This routine deals with acks during a TLP episode and ends an episode by
@@ -3856,12 +3878,23 @@ static void tcp_process_tlp_ack(struct sock *sk, u32 ack, int flag)
 	}
 }
 
-static inline void tcp_in_ack_event(struct sock *sk, u32 flags)
+static void tcp_in_ack_event(struct sock *sk, int flag)
 {
 	const struct inet_connection_sock *icsk = inet_csk(sk);
 
-	if (icsk->icsk_ca_ops->in_ack_event)
-		icsk->icsk_ca_ops->in_ack_event(sk, flags);
+	if (icsk->icsk_ca_ops->in_ack_event) {
+		u32 ack_ev_flags = 0;
+
+		if (flag & FLAG_WIN_UPDATE)
+			ack_ev_flags |= CA_ACK_WIN_UPDATE;
+		if (flag & FLAG_SLOWPATH) {
+			ack_ev_flags |= CA_ACK_SLOWPATH;
+			if (flag & FLAG_ECE)
+				ack_ev_flags |= CA_ACK_ECE;
+		}
+
+		icsk->icsk_ca_ops->in_ack_event(sk, ack_ev_flags);
+	}
 }
 
 /* Congestion control has updated the cwnd already. So if we're in
@@ -3954,8 +3987,8 @@ static int tcp_ack(struct sock *sk, const struct sk_buff *skb, int flag)
 
 #if IS_ENABLED(CONFIG_TLS_DEVICE)
 		if (static_branch_unlikely(&clean_acked_data_enabled.key))
-			if (icsk->icsk_clean_acked)
-				icsk->icsk_clean_acked(sk, ack);
+			if (tp->tcp_clean_acked)
+				tp->tcp_clean_acked(sk, ack);
 #endif
 	}
 
@@ -3966,7 +3999,7 @@ static int tcp_ack(struct sock *sk, const struct sk_buff *skb, int flag)
 	 * is in window.
 	 */
 	if (flag & FLAG_UPDATE_TS_RECENT)
-		tcp_replace_ts_recent(tp, TCP_SKB_CB(skb)->seq);
+		flag |= tcp_replace_ts_recent(tp, TCP_SKB_CB(skb)->seq);
 
 	if ((flag & (FLAG_SLOWPATH | FLAG_SND_UNA_ADVANCED)) ==
 	    FLAG_SND_UNA_ADVANCED) {
@@ -3978,12 +4011,8 @@ static int tcp_ack(struct sock *sk, const struct sk_buff *skb, int flag)
 		tcp_snd_una_update(tp, ack);
 		flag |= FLAG_WIN_UPDATE;
 
-		tcp_in_ack_event(sk, CA_ACK_WIN_UPDATE);
-
 		NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPHPACKS);
 	} else {
-		u32 ack_ev_flags = CA_ACK_SLOWPATH;
-
 		if (ack_seq != TCP_SKB_CB(skb)->end_seq)
 			flag |= FLAG_DATA;
 		else
@@ -3995,19 +4024,12 @@ static int tcp_ack(struct sock *sk, const struct sk_buff *skb, int flag)
 			flag |= tcp_sacktag_write_queue(sk, skb, prior_snd_una,
 							&sack_state);
 
-		if (tcp_ecn_rcv_ecn_echo(tp, tcp_hdr(skb))) {
+		if (tcp_ecn_rcv_ecn_echo(tp, tcp_hdr(skb)))
 			flag |= FLAG_ECE;
-			ack_ev_flags |= CA_ACK_ECE;
-		}
 
 		if (sack_state.sack_delivered)
 			tcp_count_delivered(tp, sack_state.sack_delivered,
 					    flag & FLAG_ECE);
-
-		if (flag & FLAG_WIN_UPDATE)
-			ack_ev_flags |= CA_ACK_WIN_UPDATE;
-
-		tcp_in_ack_event(sk, ack_ev_flags);
 	}
 
 	/* This is a deviation from RFC3168 since it states that:
@@ -4034,6 +4056,8 @@ static int tcp_ack(struct sock *sk, const struct sk_buff *skb, int flag)
 
 	tcp_rack_update_reo_wnd(sk, &rs);
 
+	tcp_in_ack_event(sk, flag);
+
 	if (tp->tlp_high_seq)
 		tcp_process_tlp_ack(sk, ack, flag);
 
@@ -4065,6 +4089,7 @@ static int tcp_ack(struct sock *sk, const struct sk_buff *skb, int flag)
 	return 1;
 
 no_queue:
+	tcp_in_ack_event(sk, flag);
 	/* If data was DSACKed, see if we can undo a cwnd reduction. */
 	if (flag & FLAG_DSACKING_ACK) {
 		tcp_fastretrans_alert(sk, prior_snd_una, num_dupack, &flag,
@@ -4174,7 +4199,6 @@ u16 tcp_parse_mss_option(const struct tcphdr *th, u16 user_mss)
 	}
 	return mss;
 }
-EXPORT_SYMBOL_GPL(tcp_parse_mss_option);
 
 /* Look for tcp options. Normally only called on SYN and SYNACK packets.
  * But, this can also be called on packets in the established flow when
@@ -4450,34 +4474,40 @@ static u32 tcp_tsval_replay(const struct sock *sk)
 	return inet_csk(sk)->icsk_rto * 1200 / HZ;
 }
 
-static int tcp_disordered_ack(const struct sock *sk, const struct sk_buff *skb)
+static enum skb_drop_reason tcp_disordered_ack_check(const struct sock *sk,
+						     const struct sk_buff *skb)
 {
 	const struct tcp_sock *tp = tcp_sk(sk);
 	const struct tcphdr *th = tcp_hdr(skb);
-	u32 seq = TCP_SKB_CB(skb)->seq;
+	SKB_DR_INIT(reason, TCP_RFC7323_PAWS);
 	u32 ack = TCP_SKB_CB(skb)->ack_seq;
+	u32 seq = TCP_SKB_CB(skb)->seq;
 
-	return	/* 1. Pure ACK with correct sequence number. */
-		(th->ack && seq == TCP_SKB_CB(skb)->end_seq && seq == tp->rcv_nxt) &&
+	/* 1. Is this not a pure ACK ? */
+	if (!th->ack || seq != TCP_SKB_CB(skb)->end_seq)
+		return reason;
 
-		/* 2. ... and duplicate ACK. */
-		ack == tp->snd_una &&
+	/* 2. Is its sequence not the expected one ? */
+	if (seq != tp->rcv_nxt)
+		return before(seq, tp->rcv_nxt) ?
+			SKB_DROP_REASON_TCP_RFC7323_PAWS_ACK :
+			reason;
 
-		/* 3. ... and does not update window. */
-		!tcp_may_update_window(tp, ack, seq, ntohs(th->window) << tp->rx_opt.snd_wscale) &&
+	/* 3. Is this not a duplicate ACK ? */
+	if (ack != tp->snd_una)
+		return reason;
 
-		/* 4. ... and sits in replay window. */
-		(s32)(tp->rx_opt.ts_recent - tp->rx_opt.rcv_tsval) <=
-		tcp_tsval_replay(sk);
-}
+	/* 4. Is this updating the window ? */
+	if (tcp_may_update_window(tp, ack, seq, ntohs(th->window) <<
+						tp->rx_opt.snd_wscale))
+		return reason;
 
-static inline bool tcp_paws_discard(const struct sock *sk,
-				   const struct sk_buff *skb)
-{
-	const struct tcp_sock *tp = tcp_sk(sk);
+	/* 5. Is this not in the replay window ? */
+	if ((s32)(tp->rx_opt.ts_recent - tp->rx_opt.rcv_tsval) >
+	    tcp_tsval_replay(sk))
+		return reason;
 
-	return !tcp_paws_check(&tp->rx_opt, TCP_PAWS_WINDOW) &&
-	       !tcp_disordered_ack(sk, skb);
+	return 0;
 }
 
 /* Check segment sequence number for validity.
@@ -4518,7 +4548,7 @@ void tcp_done_with_error(struct sock *sk, int err)
 	if (!sock_flag(sk, SOCK_DEAD))
 		sk_error_report(sk);
 }
-EXPORT_SYMBOL(tcp_done_with_error);
+EXPORT_IPV6_MOD(tcp_done_with_error);
 
 /* When we get a reset we do this. */
 void tcp_reset(struct sock *sk, struct sk_buff *skb)
@@ -4964,7 +4994,7 @@ static void tcp_ofo_queue(struct sock *sk)
 		tcp_rcv_nxt_update(tp, TCP_SKB_CB(skb)->end_seq);
 		fin = TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN;
 		if (!eaten)
-			__skb_queue_tail(&sk->sk_receive_queue, skb);
+			tcp_add_receive_queue(sk, skb);
 		else
 			kfree_skb_partial(skb, fragstolen);
 
@@ -5007,7 +5037,7 @@ static void tcp_data_queue_ofo(struct sock *sk, struct sk_buff *skb)
 	bool fragstolen;
 
 	tcp_save_lrcv_flowlabel(sk, skb);
-	tcp_ecn_check_ce(sk, skb);
+	tcp_data_ecn_check(sk, skb);
 
 	if (unlikely(tcp_try_rmem_schedule(sk, skb, skb->truesize))) {
 		NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPOFODROP);
@@ -5141,7 +5171,7 @@ end:
 		if (tcp_is_sack(tp))
 			tcp_grow_window(sk, skb, false);
 		skb_condense(skb);
-		skb_set_owner_r(skb, sk);
+		tcp_skb_set_owner_r(skb, sk);
 	}
 }
 
@@ -5156,8 +5186,8 @@ static int __must_check tcp_queue_rcv(struct sock *sk, struct sk_buff *skb,
 				  skb, fragstolen)) ? 1 : 0;
 	tcp_rcv_nxt_update(tcp_sk(sk), TCP_SKB_CB(skb)->end_seq);
 	if (!eaten) {
-		__skb_queue_tail(&sk->sk_receive_queue, skb);
-		skb_set_owner_r(skb, sk);
+		tcp_add_receive_queue(sk, skb);
+		tcp_skb_set_owner_r(skb, sk);
 	}
 	return eaten;
 }
@@ -5239,7 +5269,7 @@ static void tcp_data_queue(struct sock *sk, struct sk_buff *skb)
 		__kfree_skb(skb);
 		return;
 	}
-	skb_dst_drop(skb);
+	tcp_cleanup_skb(skb);
 	__skb_pull(skb, tcp_hdr(skb)->doff * 4);
 
 	reason = SKB_DROP_REASON_NOT_SPECIFIED;
@@ -5474,7 +5504,7 @@ skip_this:
 			__skb_queue_before(list, skb, nskb);
 		else
 			__skb_queue_tail(&tmp, nskb); /* defer rbtree insertion */
-		skb_set_owner_r(nskb, sk);
+		tcp_skb_set_owner_r(nskb, sk);
 		mptcp_skb_ext_move(nskb, skb);
 
 		/* Copy data, releasing collapsed skbs. */
@@ -5949,23 +5979,35 @@ static bool tcp_validate_incoming(struct sock *sk, struct sk_buff *skb,
 	SKB_DR(reason);
 
 	/* RFC1323: H1. Apply PAWS check first. */
-	if (tcp_fast_parse_options(sock_net(sk), skb, th, tp) &&
-	    tp->rx_opt.saw_tstamp &&
-	    tcp_paws_discard(sk, skb)) {
-		if (!th->rst) {
-			if (unlikely(th->syn))
-				goto syn_challenge;
-			NET_INC_STATS(sock_net(sk), LINUX_MIB_PAWSESTABREJECTED);
-			if (!tcp_oow_rate_limited(sock_net(sk), skb,
-						  LINUX_MIB_TCPACKSKIPPEDPAWS,
-						  &tp->last_oow_ack_time))
-				tcp_send_dupack(sk, skb);
-			SKB_DR_SET(reason, TCP_RFC7323_PAWS);
-			goto discard;
-		}
-		/* Reset is accepted even if it did not pass PAWS. */
+	if (!tcp_fast_parse_options(sock_net(sk), skb, th, tp) ||
+	    !tp->rx_opt.saw_tstamp ||
+	    tcp_paws_check(&tp->rx_opt, TCP_PAWS_WINDOW))
+		goto step1;
+
+	reason = tcp_disordered_ack_check(sk, skb);
+	if (!reason)
+		goto step1;
+	/* Reset is accepted even if it did not pass PAWS. */
+	if (th->rst)
+		goto step1;
+	if (unlikely(th->syn))
+		goto syn_challenge;
+
+	/* Old ACK are common, increment PAWS_OLD_ACK
+	 * and do not send a dupack.
+	 */
+	if (reason == SKB_DROP_REASON_TCP_RFC7323_PAWS_ACK) {
+		NET_INC_STATS(sock_net(sk), LINUX_MIB_PAWS_OLD_ACK);
+		goto discard;
 	}
+	NET_INC_STATS(sock_net(sk), LINUX_MIB_PAWSESTABREJECTED);
+	if (!tcp_oow_rate_limited(sock_net(sk), skb,
+				  LINUX_MIB_TCPACKSKIPPEDPAWS,
+				  &tp->last_oow_ack_time))
+		tcp_send_dupack(sk, skb);
+	goto discard;
 
+step1:
 	/* Step 1: check sequence number */
 	reason = tcp_sequence(tp, TCP_SKB_CB(skb)->seq, TCP_SKB_CB(skb)->end_seq);
 	if (reason) {
@@ -6132,6 +6174,8 @@ void tcp_rcv_established(struct sock *sk, struct sk_buff *skb)
 	    TCP_SKB_CB(skb)->seq == tp->rcv_nxt &&
 	    !after(TCP_SKB_CB(skb)->ack_seq, tp->snd_nxt)) {
 		int tcp_header_len = tp->tcp_header_len;
+		s32 delta = 0;
+		int flag = 0;
 
 		/* Timestamp header prediction: tcp_header_len
 		 * is automatically equal to th->doff*4 due to pred_flags
@@ -6144,8 +6188,10 @@ void tcp_rcv_established(struct sock *sk, struct sk_buff *skb)
 			if (!tcp_parse_aligned_timestamp(tp, th))
 				goto slow_path;
 
+			delta = tp->rx_opt.rcv_tsval -
+				tp->rx_opt.ts_recent;
 			/* If PAWS failed, check it more carefully in slow path */
-			if ((s32)(tp->rx_opt.rcv_tsval - tp->rx_opt.ts_recent) < 0)
+			if (delta < 0)
 				goto slow_path;
 
 			/* DO NOT update ts_recent here, if checksum fails
@@ -6165,12 +6211,13 @@ void tcp_rcv_established(struct sock *sk, struct sk_buff *skb)
 				if (tcp_header_len ==
 				    (sizeof(struct tcphdr) + TCPOLEN_TSTAMP_ALIGNED) &&
 				    tp->rcv_nxt == tp->rcv_wup)
-					tcp_store_ts_recent(tp);
+					flag |= __tcp_replace_ts_recent(tp,
+									delta);
 
 				/* We know that such packets are checksummed
 				 * on entry.
 				 */
-				tcp_ack(sk, skb, 0);
+				tcp_ack(sk, skb, flag);
 				__kfree_skb(skb);
 				tcp_data_snd_check(sk);
 				/* When receiving pure ack in fast path, update
@@ -6201,14 +6248,15 @@ void tcp_rcv_established(struct sock *sk, struct sk_buff *skb)
 			if (tcp_header_len ==
 			    (sizeof(struct tcphdr) + TCPOLEN_TSTAMP_ALIGNED) &&
 			    tp->rcv_nxt == tp->rcv_wup)
-				tcp_store_ts_recent(tp);
+				flag |= __tcp_replace_ts_recent(tp,
+								delta);
 
 			tcp_rcv_rtt_measure_ts(sk, skb);
 
 			NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPHPHITS);
 
 			/* Bulk data transfer: receiver */
-			skb_dst_drop(skb);
+			tcp_cleanup_skb(skb);
 			__skb_pull(skb, tcp_header_len);
 			eaten = tcp_queue_rcv(sk, skb, &fragstolen);
 
@@ -6216,7 +6264,7 @@ void tcp_rcv_established(struct sock *sk, struct sk_buff *skb)
 
 			if (TCP_SKB_CB(skb)->ack_seq != tp->snd_una) {
 				/* Well, only one small jumplet in fast path... */
-				tcp_ack(sk, skb, FLAG_DATA);
+				tcp_ack(sk, skb, flag | FLAG_DATA);
 				tcp_data_snd_check(sk);
 				if (!inet_csk_ack_scheduled(sk))
 					goto no_ack;
@@ -6276,7 +6324,7 @@ csum_error:
 discard:
 	tcp_drop_reason(sk, skb, reason);
 }
-EXPORT_SYMBOL(tcp_rcv_established);
+EXPORT_IPV6_MOD(tcp_rcv_established);
 
 void tcp_init_transfer(struct sock *sk, int bpf_op, struct sk_buff *skb)
 {
@@ -6329,7 +6377,7 @@ void tcp_finish_connect(struct sock *sk, struct sk_buff *skb)
 	tp->lsndtime = tcp_jiffies32;
 
 	if (sock_flag(sk, SOCK_KEEPOPEN))
-		inet_csk_reset_keepalive_timer(sk, keepalive_time_when(tp));
+		tcp_reset_keepalive_timer(sk, keepalive_time_when(tp));
 
 	if (!tp->rx_opt.snd_wscale)
 		__tcp_fast_path_on(tp, tp->snd_wnd);
@@ -6452,9 +6500,8 @@ static int tcp_rcv_synsent_state_process(struct sock *sk, struct sk_buff *skb,
 		    after(TCP_SKB_CB(skb)->ack_seq, tp->snd_nxt)) {
 			/* Previous FIN/ACK or RST/ACK might be ignored. */
 			if (icsk->icsk_retransmits == 0)
-				inet_csk_reset_xmit_timer(sk,
-						ICSK_TIME_RETRANS,
-						TCP_TIMEOUT_MIN, TCP_RTO_MAX);
+				tcp_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
+						     TCP_TIMEOUT_MIN, false);
 			SKB_DR_SET(reason, TCP_INVALID_ACK_SEQUENCE);
 			goto reset_and_undo;
 		}
@@ -6569,8 +6616,8 @@ consume:
 			 */
 			inet_csk_schedule_ack(sk);
 			tcp_enter_quickack_mode(sk, TCP_MAX_QUICKACKS);
-			inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK,
-						  TCP_DELACK_MAX, TCP_RTO_MAX);
+			tcp_reset_xmit_timer(sk, ICSK_TIME_DACK,
+					     TCP_DELACK_MAX, false);
 			goto consume;
 		}
 		tcp_send_ack(sk);
@@ -6788,10 +6835,9 @@ tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb)
 		WARN_ON_ONCE(sk->sk_state != TCP_SYN_RECV &&
 		    sk->sk_state != TCP_FIN_WAIT1);
 
-		if (!tcp_check_req(sk, skb, req, true, &req_stolen)) {
-			SKB_DR_SET(reason, TCP_FASTOPEN);
+		SKB_DR_SET(reason, TCP_FASTOPEN);
+		if (!tcp_check_req(sk, skb, req, true, &req_stolen, &reason))
 			goto discard;
-		}
 	}
 
 	if (!th->ack && !th->rst && !th->syn) {
@@ -6904,7 +6950,7 @@ tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb)
 
 		tmo = tcp_fin_time(sk);
 		if (tmo > TCP_TIMEWAIT_LEN) {
-			inet_csk_reset_keepalive_timer(sk, tmo - TCP_TIMEWAIT_LEN);
+			tcp_reset_keepalive_timer(sk, tmo - TCP_TIMEWAIT_LEN);
 		} else if (th->fin || sock_owned_by_user(sk)) {
 			/* Bad case. We could lose such FIN otherwise.
 			 * It is not a big problem, but it looks confusing
@@ -6912,7 +6958,7 @@ tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb)
 			 * if it spins in bh_lock_sock(), but it is really
 			 * marginal case.
 			 */
-			inet_csk_reset_keepalive_timer(sk, tmo);
+			tcp_reset_keepalive_timer(sk, tmo);
 		} else {
 			tcp_time_wait(sk, TCP_FIN_WAIT2, tmo);
 			goto consume;
@@ -6990,7 +7036,7 @@ consume:
 	__kfree_skb(skb);
 	return 0;
 }
-EXPORT_SYMBOL(tcp_rcv_state_process);
+EXPORT_IPV6_MOD(tcp_rcv_state_process);
 
 static inline void pr_drop_req(struct request_sock *req, __u16 port, int family)
 {
@@ -7057,6 +7103,7 @@ static void tcp_openreq_init(struct request_sock *req,
 	tcp_rsk(req)->rcv_isn = TCP_SKB_CB(skb)->seq;
 	tcp_rsk(req)->rcv_nxt = TCP_SKB_CB(skb)->seq + 1;
 	tcp_rsk(req)->snt_synack = 0;
+	tcp_rsk(req)->snt_tsval_first = 0;
 	tcp_rsk(req)->last_oow_ack_time = 0;
 	req->mss = rx_opt->mss_clamp;
 	req->ts_recent = rx_opt->saw_tstamp ? rx_opt->rcv_tsval : 0;
@@ -7172,7 +7219,7 @@ u16 tcp_get_syncookie_mss(struct request_sock_ops *rsk_ops,
 
 	return mss;
 }
-EXPORT_SYMBOL_GPL(tcp_get_syncookie_mss);
+EXPORT_IPV6_MOD_GPL(tcp_get_syncookie_mss);
 
 int tcp_conn_request(struct request_sock_ops *rsk_ops,
 		     const struct tcp_request_sock_ops *af_ops,
@@ -7353,4 +7400,4 @@ drop:
 	tcp_listendrop(sk);
 	return 0;
 }
-EXPORT_SYMBOL(tcp_conn_request);
+EXPORT_IPV6_MOD(tcp_conn_request);