1 files changed, 65 insertions, 51 deletions

diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 12b98e257c5f..d3b7172b9ee0 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -102,6 +102,7 @@ int sysctl_tcp_thin_dupack __read_mostly;
 int sysctl_tcp_moderate_rcvbuf __read_mostly = 1;
 int sysctl_tcp_early_retrans __read_mostly = 3;
 int sysctl_tcp_invalid_ratelimit __read_mostly = HZ/2;
+int sysctl_tcp_default_init_rwnd __read_mostly = TCP_INIT_CWND * 2;
 
 #define FLAG_DATA		0x01 /* Incoming frame contained data.		*/
 #define FLAG_WIN_UPDATE		0x02 /* Incoming ACK was a window update.	*/
@@ -117,6 +118,7 @@ int sysctl_tcp_invalid_ratelimit __read_mostly = HZ/2;
 #define FLAG_DSACKING_ACK	0x800 /* SACK blocks contained D-SACK info */
 #define FLAG_SACK_RENEGING	0x2000 /* snd_una advanced to a sacked seq */
 #define FLAG_UPDATE_TS_RECENT	0x4000 /* tcp_replace_ts_recent() */
+#define FLAG_NO_CHALLENGE_ACK	0x8000 /* do not call tcp_send_challenge_ack()	*/
 
 #define FLAG_ACKED		(FLAG_DATA_ACKED|FLAG_SYN_ACKED)
 #define FLAG_NOT_DUP		(FLAG_DATA|FLAG_WIN_UPDATE|FLAG_ACKED)
@@ -556,8 +558,8 @@ static inline void tcp_rcv_rtt_measure_ts(struct sock *sk,
 void tcp_rcv_space_adjust(struct sock *sk)
 {
 	struct tcp_sock *tp = tcp_sk(sk);
+	u32 copied;
 	int time;
-	int copied;
 
 	time = tcp_time_stamp - tp->rcvq_space.time;
 	if (time < (tp->rcv_rtt_est.rtt >> 3) || tp->rcv_rtt_est.rtt == 0)
@@ -579,12 +581,13 @@ void tcp_rcv_space_adjust(struct sock *sk)
 
 	if (sysctl_tcp_moderate_rcvbuf &&
 	    !(sk->sk_userlocks & SOCK_RCVBUF_LOCK)) {
-		int rcvwin, rcvmem, rcvbuf;
+		int rcvmem, rcvbuf;
+		u64 rcvwin;
 
 		/* minimal window to cope with packet losses, assuming
 		 * steady state. Add some cushion because of small variations.
 		 */
-		rcvwin = (copied << 1) + 16 * tp->advmss;
+		rcvwin = ((u64)copied << 1) + 16 * tp->advmss;
 
 		/* If rate increased by 25%,
 		 *	assume slow start, rcvwin = 3 * copied
@@ -604,12 +607,13 @@ void tcp_rcv_space_adjust(struct sock *sk)
 		while (tcp_win_from_space(rcvmem) < tp->advmss)
 			rcvmem += 128;
 
-		rcvbuf = min(rcvwin / tp->advmss * rcvmem, sysctl_tcp_rmem[2]);
+		do_div(rcvwin, tp->advmss);
+		rcvbuf = min_t(u64, rcvwin * rcvmem, sysctl_tcp_rmem[2]);
 		if (rcvbuf > sk->sk_rcvbuf) {
 			sk->sk_rcvbuf = rcvbuf;
 
 			/* Make the window clamp follow along.  */
-			tp->window_clamp = rcvwin;
+			tp->window_clamp = tcp_win_from_space(rcvbuf);
 		}
 	}
 	tp->rcvq_space.space = copied;
@@ -1134,13 +1138,14 @@ static int tcp_match_skb_to_sack(struct sock *sk, struct sk_buff *skb,
 		 */
 		if (pkt_len > mss) {
 			unsigned int new_len = (pkt_len / mss) * mss;
-			if (!in_sack && new_len < pkt_len) {
+			if (!in_sack && new_len < pkt_len)
 				new_len += mss;
-				if (new_len >= skb->len)
-					return 0;
-			}
 			pkt_len = new_len;
 		}
+
+		if (pkt_len >= skb->len && !in_sack)
+			return 0;
+
 		err = tcp_fragment(sk, skb, pkt_len, mss, GFP_ATOMIC);
 		if (err < 0)
 			return err;
@@ -2164,8 +2169,7 @@ static void tcp_mark_head_lost(struct sock *sk, int packets, int mark_head)
 {
 	struct tcp_sock *tp = tcp_sk(sk);
 	struct sk_buff *skb;
-	int cnt, oldcnt;
-	int err;
+	int cnt, oldcnt, lost;
 	unsigned int mss;
 	/* Use SACK to deduce losses of new sequences sent during recovery */
 	const u32 loss_high = tcp_is_sack(tp) ?  tp->snd_nxt : tp->high_seq;
@@ -2205,9 +2209,10 @@ static void tcp_mark_head_lost(struct sock *sk, int packets, int mark_head)
 				break;
 
 			mss = tcp_skb_mss(skb);
-			err = tcp_fragment(sk, skb, (packets - oldcnt) * mss,
-					   mss, GFP_ATOMIC);
-			if (err < 0)
+			/* If needed, chop off the prefix to mark as lost. */
+			lost = (packets - oldcnt) * mss;
+			if (lost < skb->len &&
+			    tcp_fragment(sk, skb, lost, mss, GFP_ATOMIC) < 0)
 				break;
 			cnt = packets;
 		}
@@ -2324,10 +2329,9 @@ static void DBGUNDO(struct sock *sk, const char *msg)
 	}
 #if IS_ENABLED(CONFIG_IPV6)
 	else if (sk->sk_family == AF_INET6) {
-		struct ipv6_pinfo *np = inet6_sk(sk);
 		pr_debug("Undo %s %pI6/%u c%u l%u ss%u/%u p%u\n",
 			 msg,
-			 &np->daddr, ntohs(inet->inet_dport),
+			 &sk->sk_v6_daddr, ntohs(inet->inet_dport),
 			 tp->snd_cwnd, tcp_left_out(tp),
 			 tp->snd_ssthresh, tp->prior_ssthresh,
 			 tp->packets_out);
@@ -2503,8 +2507,8 @@ static inline void tcp_end_cwnd_reduction(struct sock *sk)
 	struct tcp_sock *tp = tcp_sk(sk);
 
 	/* Reset cwnd to ssthresh in CWR or Recovery (unless it's undone) */
-	if (inet_csk(sk)->icsk_ca_state == TCP_CA_CWR ||
-	    (tp->undo_marker && tp->snd_ssthresh < TCP_INFINITE_SSTHRESH)) {
+	if (tp->snd_ssthresh < TCP_INFINITE_SSTHRESH &&
+	    (inet_csk(sk)->icsk_ca_state == TCP_CA_CWR || tp->undo_marker)) {
 		tp->snd_cwnd = tp->snd_ssthresh;
 		tp->snd_cwnd_stamp = tcp_time_stamp;
 	}
@@ -3028,8 +3032,7 @@ void tcp_rearm_rto(struct sock *sk)
 			/* delta may not be positive if the socket is locked
 			 * when the retrans timer fires and is rescheduled.
 			 */
-			if (delta > 0)
-				rto = delta;
+			rto = max(delta, 1);
 		}
 		inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS, rto,
 					  TCP_RTO_MAX);
@@ -3220,7 +3223,7 @@ static int tcp_clean_rtx_queue(struct sock *sk, int prior_fackets,
 			int delta;
 
 			/* Non-retransmitted hole got filled? That's reordering */
-			if (reord < prior_fackets)
+			if (reord < prior_fackets && reord <= tp->fackets_out)
 				tcp_update_reordering(sk, tp->fackets_out - reord, 0);
 
 			delta = tcp_is_fack(tp) ? pkts_acked :
@@ -3544,7 +3547,8 @@ static int tcp_ack(struct sock *sk, const struct sk_buff *skb, int flag)
 	if (before(ack, prior_snd_una)) {
 		/* RFC 5961 5.2 [Blind Data Injection Attack].[Mitigation] */
 		if (before(ack, prior_snd_una - tp->max_window)) {
-			tcp_send_challenge_ack(sk, skb);
+			if (!(flag & FLAG_NO_CHALLENGE_ACK))
+				tcp_send_challenge_ack(sk, skb);
 			return -1;
 		}
 		goto old_ack;
@@ -3868,11 +3872,8 @@ const u8 *tcp_parse_md5sig_option(const struct tcphdr *th)
 	int length = (th->doff << 2) - sizeof(*th);
 	const u8 *ptr = (const u8 *)(th + 1);
 
-	/* If the TCP option is too short, we can short cut */
-	if (length < TCPOLEN_MD5SIG)
-		return NULL;
-
-	while (length > 0) {
+	/* If not enough data remaining, we can short cut */
+	while (length >= TCPOLEN_MD5SIG) {
 		int opcode = *ptr++;
 		int opsize;
 
@@ -4779,6 +4780,7 @@ restart:
 static void tcp_collapse_ofo_queue(struct sock *sk)
 {
 	struct tcp_sock *tp = tcp_sk(sk);
+	u32 range_truesize, sum_tiny = 0;
 	struct sk_buff *skb = skb_peek(&tp->out_of_order_queue);
 	struct sk_buff *head;
 	u32 start, end;
@@ -4788,6 +4790,7 @@ static void tcp_collapse_ofo_queue(struct sock *sk)
 
 	start = TCP_SKB_CB(skb)->seq;
 	end = TCP_SKB_CB(skb)->end_seq;
+	range_truesize = skb->truesize;
 	head = skb;
 
 	for (;;) {
@@ -4802,14 +4805,24 @@ static void tcp_collapse_ofo_queue(struct sock *sk)
 		if (!skb ||
 		    after(TCP_SKB_CB(skb)->seq, end) ||
 		    before(TCP_SKB_CB(skb)->end_seq, start)) {
-			tcp_collapse(sk, &tp->out_of_order_queue,
-				     head, skb, start, end);
+			/* Do not attempt collapsing tiny skbs */
+			if (range_truesize != head->truesize ||
+			    end - start >= SKB_WITH_OVERHEAD(SK_MEM_QUANTUM)) {
+				tcp_collapse(sk, &tp->out_of_order_queue,
+					     head, skb, start, end);
+			} else {
+				sum_tiny += range_truesize;
+				if (sum_tiny > sk->sk_rcvbuf >> 3)
+					return;
+			}
+
 			head = skb;
 			if (!skb)
 				break;
 			/* Start new segment */
 			start = TCP_SKB_CB(skb)->seq;
 			end = TCP_SKB_CB(skb)->end_seq;
+			range_truesize = skb->truesize;
 		} else {
 			if (before(TCP_SKB_CB(skb)->seq, start))
 				start = TCP_SKB_CB(skb)->seq;
@@ -4865,6 +4878,9 @@ static int tcp_prune_queue(struct sock *sk)
 	else if (tcp_under_memory_pressure(sk))
 		tp->rcv_ssthresh = min(tp->rcv_ssthresh, 4U * tp->advmss);
 
+	if (atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf)
+		return 0;
+
 	tcp_collapse_ofo_queue(sk);
 	if (!skb_queue_empty(&sk->sk_receive_queue))
 		tcp_collapse(sk, &sk->sk_receive_queue,
@@ -4943,7 +4959,7 @@ static void tcp_check_space(struct sock *sk)
 	if (sock_flag(sk, SOCK_QUEUE_SHRUNK)) {
 		sock_reset_flag(sk, SOCK_QUEUE_SHRUNK);
 		/* pairs with tcp_poll() */
-		smp_mb__after_atomic();
+		smp_mb();
 		if (sk->sk_socket &&
 		    test_bit(SOCK_NOSPACE, &sk->sk_socket->flags))
 			tcp_new_space(sk);
@@ -5436,6 +5452,7 @@ void tcp_finish_connect(struct sock *sk, struct sk_buff *skb)
 	struct inet_connection_sock *icsk = inet_csk(sk);
 
 	tcp_set_state(sk, TCP_ESTABLISHED);
+	icsk->icsk_ack.lrcvtime = tcp_time_stamp;
 
 	if (skb) {
 		icsk->icsk_af_ops->sk_rx_dst_set(sk, skb);
@@ -5464,10 +5481,6 @@ void tcp_finish_connect(struct sock *sk, struct sk_buff *skb)
 	else
 		tp->pred_flags = 0;
 
-	if (!sock_flag(sk, SOCK_DEAD)) {
-		sk->sk_state_change(sk);
-		sk_wake_async(sk, SOCK_WAKE_IO, POLL_OUT);
-	}
 }
 
 static bool tcp_rcv_fastopen_synack(struct sock *sk, struct sk_buff *synack,
@@ -5531,6 +5544,7 @@ static int tcp_rcv_synsent_state_process(struct sock *sk, struct sk_buff *skb,
 	struct tcp_sock *tp = tcp_sk(sk);
 	struct tcp_fastopen_cookie foc = { .len = -1 };
 	int saved_clamp = tp->rx_opt.mss_clamp;
+	bool fastopen_fail;
 
 	tcp_parse_options(skb, &tp->rx_opt, 0, &foc);
 	if (tp->rx_opt.saw_tstamp && tp->rx_opt.rcv_tsecr)
@@ -5633,10 +5647,15 @@ static int tcp_rcv_synsent_state_process(struct sock *sk, struct sk_buff *skb,
 
 		tcp_finish_connect(sk, skb);
 
-		if ((tp->syn_fastopen || tp->syn_data) &&
-		    tcp_rcv_fastopen_synack(sk, skb, &foc))
-			return -1;
+		fastopen_fail = (tp->syn_fastopen || tp->syn_data) &&
+				tcp_rcv_fastopen_synack(sk, skb, &foc);
 
+		if (!sock_flag(sk, SOCK_DEAD)) {
+			sk->sk_state_change(sk);
+			sk_wake_async(sk, SOCK_WAKE_IO, POLL_OUT);
+		}
+		if (fastopen_fail)
+			return -1;
 		if (sk->sk_write_pending ||
 		    icsk->icsk_accept_queue.rskq_defer_accept ||
 		    icsk->icsk_ack.pingpong) {
@@ -5648,7 +5667,6 @@ static int tcp_rcv_synsent_state_process(struct sock *sk, struct sk_buff *skb,
 			 * to stand against the temptation 8)     --ANK
 			 */
 			inet_csk_schedule_ack(sk);
-			icsk->icsk_ack.lrcvtime = tcp_time_stamp;
 			tcp_enter_quickack_mode(sk);
 			inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK,
 						  TCP_DELACK_MAX, TCP_RTO_MAX);
@@ -5831,13 +5849,17 @@ int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb)
 
 	/* step 5: check the ACK field */
 	acceptable = tcp_ack(sk, skb, FLAG_SLOWPATH |
-				      FLAG_UPDATE_TS_RECENT) > 0;
+				      FLAG_UPDATE_TS_RECENT |
+				      FLAG_NO_CHALLENGE_ACK) > 0;
 
+	if (!acceptable) {
+		if (sk->sk_state == TCP_SYN_RECV)
+			return 1;	/* send one RST */
+		tcp_send_challenge_ack(sk, skb);
+		goto discard;
+	}
 	switch (sk->sk_state) {
 	case TCP_SYN_RECV:
-		if (!acceptable)
-			return 1;
-
 		if (!tp->srtt_us)
 			tcp_synack_rtt_meas(sk, req);
 
@@ -5906,14 +5928,6 @@ int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb)
 		 * our SYNACK so stop the SYNACK timer.
 		 */
 		if (req) {
-			/* Return RST if ack_seq is invalid.
-			 * Note that RFC793 only says to generate a
-			 * DUPACK for it but for TCP Fast Open it seems
-			 * better to treat this case like TCP_SYN_RECV
-			 * above.
-			 */
-			if (!acceptable)
-				return 1;
 			/* We no longer need the request sock. */
 			reqsk_fastopen_remove(sk, req, false);
 			tcp_rearm_rto(sk);
@@ -6106,7 +6120,7 @@ struct request_sock *inet_reqsk_alloc(const struct request_sock_ops *ops,
 		struct inet_request_sock *ireq = inet_rsk(req);
 
 		kmemcheck_annotate_bitfield(ireq, flags);
-		ireq->opt = NULL;
+		ireq->ireq_opt = NULL;
 		atomic64_set(&ireq->ir_cookie, 0);
 		ireq->ireq_state = TCP_NEW_SYN_RECV;
 		write_pnet(&ireq->ireq_net, sock_net(sk_listener));