X-Git-Url: https://git.openpandora.org/cgi-bin/gitweb.cgi?p=pandora-kernel.git;a=blobdiff_plain;f=net%2Fipv4%2Ftcp_input.c;h=7db22978114c6a0b391dd2d1ef99dd61e75ca4c9;hp=52b5c2d0ecd0aee7c99d1f31e8bf3a1115a293b9;hb=a0eee8681a9bc21d3f83260a8ceb3fa30236b189;hpb=044595d4e448305fbaec472eb7d22636d24e7d8c

diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 52b5c2d0ecd0..7db22978114c 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -83,9 +83,12 @@ int sysctl_tcp_ecn __read_mostly = 2;
 EXPORT_SYMBOL(sysctl_tcp_ecn);
 int sysctl_tcp_dsack __read_mostly = 1;
 int sysctl_tcp_app_win __read_mostly = 31;
-int sysctl_tcp_adv_win_scale __read_mostly = 2;
+int sysctl_tcp_adv_win_scale __read_mostly = 1;
 EXPORT_SYMBOL(sysctl_tcp_adv_win_scale);
 
+/* rfc5961 challenge ack rate limiting */
+int sysctl_tcp_challenge_ack_limit = 1000;
+
 int sysctl_tcp_stdurg __read_mostly;
 int sysctl_tcp_rfc1337 __read_mostly;
 int sysctl_tcp_max_orphans __read_mostly = NR_FILE;
@@ -112,6 +115,7 @@ int sysctl_tcp_abc __read_mostly;
 #define FLAG_DSACKING_ACK	0x800 /* SACK blocks contained D-SACK info */
 #define FLAG_NONHEAD_RETRANS_ACKED	0x1000 /* Non-head rexmitted data was ACKed */
 #define FLAG_SACK_RENEGING	0x2000 /* snd_una advanced to a sacked seq */
+#define FLAG_UPDATE_TS_RECENT	0x4000 /* tcp_replace_ts_recent() */
 
 #define FLAG_ACKED		(FLAG_DATA_ACKED|FLAG_SYN_ACKED)
 #define FLAG_NOT_DUP		(FLAG_DATA|FLAG_WIN_UPDATE|FLAG_ACKED)
@@ -334,6 +338,7 @@ static void tcp_grow_window(struct sock *sk, const struct sk_buff *skb)
 			incr = __tcp_grow_window(sk, skb);
 
 		if (incr) {
+			incr = max_t(int, incr, 2 * skb->len);
 			tp->rcv_ssthresh = min(tp->rcv_ssthresh + incr,
 					       tp->window_clamp);
 			inet_csk(sk)->icsk_ack.quick |= 1;
@@ -473,8 +478,11 @@ static void tcp_rcv_rtt_update(struct tcp_sock *tp, u32 sample, int win_dep)
 		if (!win_dep) {
 			m -= (new_sample >> 3);
 			new_sample += m;
-		} else if (m < new_sample)
-			new_sample = m << 3;
+		} else {
+			m <<= 3;
+			if (m < new_sample)
+				new_sample = m;
+		}
 	} else {
 		/* No previous measure. */
 		new_sample = m << 3;
@@ -1295,13 +1303,14 @@ 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);
 		if (err < 0)
 			return err;
@@ -1310,25 +1319,26 @@ static int tcp_match_skb_to_sack(struct sock *sk, struct sk_buff *skb,
 	return in_sack;
 }
 
-static u8 tcp_sacktag_one(const struct sk_buff *skb, struct sock *sk,
-			  struct tcp_sacktag_state *state,
+/* Mark the given newly-SACKed range as such, adjusting counters and hints. */
+static u8 tcp_sacktag_one(struct sock *sk,
+			  struct tcp_sacktag_state *state, u8 sacked,
+			  u32 start_seq, u32 end_seq,
 			  int dup_sack, int pcount)
 {
 	struct tcp_sock *tp = tcp_sk(sk);
-	u8 sacked = TCP_SKB_CB(skb)->sacked;
 	int fack_count = state->fack_count;
 
 	/* Account D-SACK for retransmitted packet. */
 	if (dup_sack && (sacked & TCPCB_RETRANS)) {
 		if (tp->undo_marker && tp->undo_retrans &&
-		    after(TCP_SKB_CB(skb)->end_seq, tp->undo_marker))
+		    after(end_seq, tp->undo_marker))
 			tp->undo_retrans--;
 		if (sacked & TCPCB_SACKED_ACKED)
 			state->reord = min(fack_count, state->reord);
 	}
 
 	/* Nothing to do; acked frame is about to be dropped (was ACKed). */
-	if (!after(TCP_SKB_CB(skb)->end_seq, tp->snd_una))
+	if (!after(end_seq, tp->snd_una))
 		return sacked;
 
 	if (!(sacked & TCPCB_SACKED_ACKED)) {
@@ -1347,13 +1357,13 @@ static u8 tcp_sacktag_one(const struct sk_buff *skb, struct sock *sk,
 				/* New sack for not retransmitted frame,
 				 * which was in hole. It is reordering.
 				 */
-				if (before(TCP_SKB_CB(skb)->seq,
+				if (before(start_seq,
 					   tcp_highest_sack_seq(tp)))
 					state->reord = min(fack_count,
 							   state->reord);
 
 				/* SACK enhanced F-RTO (RFC4138; Appendix B) */
-				if (!after(TCP_SKB_CB(skb)->end_seq, tp->frto_highmark))
+				if (!after(end_seq, tp->frto_highmark))
 					state->flag |= FLAG_ONLY_ORIG_SACKED;
 			}
 
@@ -1371,8 +1381,7 @@ static u8 tcp_sacktag_one(const struct sk_buff *skb, struct sock *sk,
 
 		/* Lost marker hint past SACKed? Tweak RFC3517 cnt */
 		if (!tcp_is_fack(tp) && (tp->lost_skb_hint != NULL) &&
-		    before(TCP_SKB_CB(skb)->seq,
-			   TCP_SKB_CB(tp->lost_skb_hint)->seq))
+		    before(start_seq, TCP_SKB_CB(tp->lost_skb_hint)->seq))
 			tp->lost_cnt_hint += pcount;
 
 		if (fack_count > tp->fackets_out)
@@ -1391,6 +1400,9 @@ static u8 tcp_sacktag_one(const struct sk_buff *skb, struct sock *sk,
 	return sacked;
 }
 
+/* Shift newly-SACKed bytes from this skb to the immediately previous
+ * already-SACKed sk_buff. Mark the newly-SACKed bytes as such.
+ */
 static int tcp_shifted_skb(struct sock *sk, struct sk_buff *skb,
 			   struct tcp_sacktag_state *state,
 			   unsigned int pcount, int shifted, int mss,
@@ -1398,9 +1410,20 @@ static int tcp_shifted_skb(struct sock *sk, struct sk_buff *skb,
 {
 	struct tcp_sock *tp = tcp_sk(sk);
 	struct sk_buff *prev = tcp_write_queue_prev(sk, skb);
+	u32 start_seq = TCP_SKB_CB(skb)->seq;	/* start of newly-SACKed */
+	u32 end_seq = start_seq + shifted;	/* end of newly-SACKed */
 
 	BUG_ON(!pcount);
 
+	/* Adjust counters and hints for the newly sacked sequence
+	 * range but discard the return value since prev is already
+	 * marked. We must tag the range first because the seq
+	 * advancement below implicitly advances
+	 * tcp_highest_sack_seq() when skb is highest_sack.
+	 */
+	tcp_sacktag_one(sk, state, TCP_SKB_CB(skb)->sacked,
+			start_seq, end_seq, dup_sack, pcount);
+
 	if (skb == tp->lost_skb_hint)
 		tp->lost_cnt_hint += pcount;
 
@@ -1408,7 +1431,7 @@ static int tcp_shifted_skb(struct sock *sk, struct sk_buff *skb,
 	TCP_SKB_CB(skb)->seq += shifted;
 
 	skb_shinfo(prev)->gso_segs += pcount;
-	BUG_ON(skb_shinfo(skb)->gso_segs < pcount);
+	WARN_ON_ONCE(tcp_skb_pcount(skb) < pcount);
 	skb_shinfo(skb)->gso_segs -= pcount;
 
 	/* When we're adding to gso_segs == 1, gso_size will be zero,
@@ -1427,9 +1450,6 @@ static int tcp_shifted_skb(struct sock *sk, struct sk_buff *skb,
 		skb_shinfo(skb)->gso_type = 0;
 	}
 
-	/* We discard results */
-	tcp_sacktag_one(skb, sk, state, dup_sack, pcount);
-
 	/* Difference in this won't matter, both ACKed by the same cumul. ACK */
 	TCP_SKB_CB(prev)->sacked |= (TCP_SKB_CB(skb)->sacked & TCPCB_EVER_RETRANS);
 
@@ -1450,7 +1470,10 @@ static int tcp_shifted_skb(struct sock *sk, struct sk_buff *skb,
 		tp->lost_cnt_hint -= tcp_skb_pcount(prev);
 	}
 
-	TCP_SKB_CB(skb)->tcp_flags |= TCP_SKB_CB(prev)->tcp_flags;
+	TCP_SKB_CB(prev)->tcp_flags |= TCP_SKB_CB(skb)->tcp_flags;
+	if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN)
+		TCP_SKB_CB(prev)->end_seq++;
+
 	if (skb == tcp_highest_sack(sk))
 		tcp_advance_highest_sack(sk, skb);
 
@@ -1476,6 +1499,21 @@ static int skb_can_shift(const struct sk_buff *skb)
 	return !skb_headlen(skb) && skb_is_nonlinear(skb);
 }
 
+int tcp_skb_shift(struct sk_buff *to, struct sk_buff *from,
+		  int pcount, int shiftlen)
+{
+	/* TCP min gso_size is 8 bytes (TCP_MIN_GSO_SIZE)
+	 * Since TCP_SKB_CB(skb)->tcp_gso_segs is 16 bits, we need
+	 * to make sure not storing more than 65535 * 8 bytes per skb,
+	 * even if current MSS is bigger.
+	 */
+	if (unlikely(to->len + shiftlen >= 65535 * TCP_MIN_GSO_SIZE))
+		return 0;
+	if (unlikely(tcp_skb_pcount(to) + pcount > 65535))
+		return 0;
+	return skb_shift(to, from, shiftlen);
+}
+
 /* Try collapsing SACK blocks spanning across multiple skbs to a single
  * skb.
  */
@@ -1487,6 +1525,7 @@ static struct sk_buff *tcp_shift_skb_data(struct sock *sk, struct sk_buff *skb,
 	struct tcp_sock *tp = tcp_sk(sk);
 	struct sk_buff *prev;
 	int mss;
+	int next_pcount;
 	int pcount = 0;
 	int len;
 	int in_sack;
@@ -1577,7 +1616,11 @@ static struct sk_buff *tcp_shift_skb_data(struct sock *sk, struct sk_buff *skb,
 		}
 	}
 
-	if (!skb_shift(prev, skb, len))
+	/* tcp_sacktag_one() won't SACK-tag ranges below snd_una */
+	if (!after(TCP_SKB_CB(skb)->seq + len, tp->snd_una))
+		goto fallback;
+
+	if (!tcp_skb_shift(prev, skb, pcount, len))
 		goto fallback;
 	if (!tcp_shifted_skb(sk, skb, state, pcount, len, mss, dup_sack))
 		goto out;
@@ -1596,9 +1639,10 @@ static struct sk_buff *tcp_shift_skb_data(struct sock *sk, struct sk_buff *skb,
 		goto out;
 
 	len = skb->len;
-	if (skb_shift(prev, skb, len)) {
-		pcount += tcp_skb_pcount(skb);
-		tcp_shifted_skb(sk, skb, state, tcp_skb_pcount(skb), len, mss, 0);
+	next_pcount = tcp_skb_pcount(skb);
+	if (tcp_skb_shift(prev, skb, next_pcount, len)) {
+		pcount += next_pcount;
+		tcp_shifted_skb(sk, skb, state, next_pcount, len, mss, 0);
 	}
 
 out:
@@ -1667,10 +1711,14 @@ static struct sk_buff *tcp_sacktag_walk(struct sk_buff *skb, struct sock *sk,
 			break;
 
 		if (in_sack) {
-			TCP_SKB_CB(skb)->sacked = tcp_sacktag_one(skb, sk,
-								  state,
-								  dup_sack,
-								  tcp_skb_pcount(skb));
+			TCP_SKB_CB(skb)->sacked =
+				tcp_sacktag_one(sk,
+						state,
+						TCP_SKB_CB(skb)->sacked,
+						TCP_SKB_CB(skb)->seq,
+						TCP_SKB_CB(skb)->end_seq,
+						dup_sack,
+						tcp_skb_pcount(skb));
 
 			if (!before(TCP_SKB_CB(skb)->seq,
 				    tcp_highest_sack_seq(tp)))
@@ -2239,11 +2287,8 @@ void tcp_enter_loss(struct sock *sk, int how)
 	if (tcp_is_reno(tp))
 		tcp_reset_reno_sack(tp);
 
-	if (!how) {
-		/* Push undo marker, if it was plain RTO and nothing
-		 * was retransmitted. */
-		tp->undo_marker = tp->snd_una;
-	} else {
+	tp->undo_marker = tp->snd_una;
+	if (how) {
 		tp->sacked_out = 0;
 		tp->fackets_out = 0;
 	}
@@ -2556,6 +2601,7 @@ static void tcp_mark_head_lost(struct sock *sk, int packets, int mark_head)
 
 		if (cnt > packets) {
 			if ((tcp_is_sack(tp) && !tcp_is_fack(tp)) ||
+			    (TCP_SKB_CB(skb)->sacked & TCPCB_SACKED_ACKED) ||
 			    (oldcnt >= packets))
 				break;
 
@@ -2844,11 +2890,14 @@ static inline void tcp_complete_cwr(struct sock *sk)
 
 	/* Do not moderate cwnd if it's already undone in cwr or recovery. */
 	if (tp->undo_marker) {
-		if (inet_csk(sk)->icsk_ca_state == TCP_CA_CWR)
+		if (inet_csk(sk)->icsk_ca_state == TCP_CA_CWR) {
 			tp->snd_cwnd = min(tp->snd_cwnd, tp->snd_ssthresh);
-		else /* PRR */
+			tp->snd_cwnd_stamp = tcp_time_stamp;
+		} else if (tp->snd_ssthresh < TCP_INFINITE_SSTHRESH) {
+			/* PRR algorithm. */
 			tp->snd_cwnd = tp->snd_ssthresh;
-		tp->snd_cwnd_stamp = tcp_time_stamp;
+			tp->snd_cwnd_stamp = tcp_time_stamp;
+		}
 	}
 	tcp_ca_event(sk, CA_EVENT_COMPLETE_CWR);
 }
@@ -3393,7 +3442,7 @@ 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 :
@@ -3625,6 +3674,11 @@ static int tcp_process_frto(struct sock *sk, int flag)
 		}
 	} else {
 		if (!(flag & FLAG_DATA_ACKED) && (tp->frto_counter == 1)) {
+			if (!tcp_packets_in_flight(tp)) {
+				tcp_enter_frto_loss(sk, 2, flag);
+				return true;
+			}
+
 			/* Prevent sending of new data. */
 			tp->snd_cwnd = min(tp->snd_cwnd,
 					   tcp_packets_in_flight(tp));
@@ -3673,6 +3727,52 @@ static int tcp_process_frto(struct sock *sk, int flag)
 	return 0;
 }
 
+/* RFC 5961 7 [ACK Throttling] */
+static void tcp_send_challenge_ack(struct sock *sk)
+{
+	/* unprotected vars, we dont care of overwrites */
+	static u32 challenge_timestamp;
+	static unsigned int challenge_count;
+	u32 count, now = jiffies / HZ;
+
+	if (now != challenge_timestamp) {
+		u32 half = (sysctl_tcp_challenge_ack_limit + 1) >> 1;
+
+		challenge_timestamp = now;
+		ACCESS_ONCE(challenge_count) =
+			half + (u32)(
+			((u64) random32() * sysctl_tcp_challenge_ack_limit)
+			>> 32);
+	}
+	count = ACCESS_ONCE(challenge_count);
+	if (count > 0) {
+		ACCESS_ONCE(challenge_count) = count - 1;
+		NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPCHALLENGEACK);
+		tcp_send_ack(sk);
+	}
+}
+
+static void tcp_store_ts_recent(struct tcp_sock *tp)
+{
+	tp->rx_opt.ts_recent = tp->rx_opt.rcv_tsval;
+	tp->rx_opt.ts_recent_stamp = get_seconds();
+}
+
+static void tcp_replace_ts_recent(struct tcp_sock *tp, u32 seq)
+{
+	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
+		 * for pure ACK frames.  -DaveM
+		 *
+		 * Not only, also it occurs for expired timestamps.
+		 */
+
+		if (tcp_paws_check(&tp->rx_opt, 0))
+			tcp_store_ts_recent(tp);
+	}
+}
+
 /* This routine deals with incoming acks, but not outgoing ones. */
 static int tcp_ack(struct sock *sk, const struct sk_buff *skb, int flag)
 {
@@ -3691,8 +3791,14 @@ static int tcp_ack(struct sock *sk, const struct sk_buff *skb, int flag)
 	/* If the ack is older than previous acks
 	 * then we can probably ignore it.
 	 */
-	if (before(ack, prior_snd_una))
+	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);
+			return -1;
+		}
 		goto old_ack;
+	}
 
 	/* If the ack includes data we haven't sent yet, discard
 	 * this segment (RFC793 Section 3.9).
@@ -3715,6 +3821,12 @@ static int tcp_ack(struct sock *sk, const struct sk_buff *skb, int flag)
 	prior_fackets = tp->fackets_out;
 	prior_in_flight = tcp_packets_in_flight(tp);
 
+	/* ts_recent update must be made after we are sure that the packet
+	 * is in window.
+	 */
+	if (flag & FLAG_UPDATE_TS_RECENT)
+		tcp_replace_ts_recent(tp, TCP_SKB_CB(skb)->seq);
+
 	if (!(flag & FLAG_SLOWPATH) && after(ack, prior_snd_una)) {
 		/* Window is constant, pure forward advance.
 		 * No more checks are required.
@@ -4005,27 +4117,6 @@ const u8 *tcp_parse_md5sig_option(const struct tcphdr *th)
 EXPORT_SYMBOL(tcp_parse_md5sig_option);
 #endif
 
-static inline void tcp_store_ts_recent(struct tcp_sock *tp)
-{
-	tp->rx_opt.ts_recent = tp->rx_opt.rcv_tsval;
-	tp->rx_opt.ts_recent_stamp = get_seconds();
-}
-
-static inline void tcp_replace_ts_recent(struct tcp_sock *tp, u32 seq)
-{
-	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
-		 * for pure ACK frames.  -DaveM
-		 *
-		 * Not only, also it occurs for expired timestamps.
-		 */
-
-		if (tcp_paws_check(&tp->rx_opt, 0))
-			tcp_store_ts_recent(tp);
-	}
-}
-
 /* Sorry, PAWS as specified is broken wrt. pure-ACKs -DaveM
  *
  * It is not fatal. If this ACK does _not_ change critical state (seqs, window)
@@ -5216,8 +5307,8 @@ out:
 /* Does PAWS and seqno based validation of an incoming segment, flags will
  * play significant role here.
  */
-static int tcp_validate_incoming(struct sock *sk, struct sk_buff *skb,
-			      const struct tcphdr *th, int syn_inerr)
+static bool tcp_validate_incoming(struct sock *sk, struct sk_buff *skb,
+				  const struct tcphdr *th, int syn_inerr)
 {
 	const u8 *hash_location;
 	struct tcp_sock *tp = tcp_sk(sk);
@@ -5242,38 +5333,48 @@ static int tcp_validate_incoming(struct sock *sk, struct sk_buff *skb,
 		 * an acknowledgment should be sent in reply (unless the RST
 		 * bit is set, if so drop the segment and return)".
 		 */
-		if (!th->rst)
+		if (!th->rst) {
+			if (th->syn)
+				goto syn_challenge;
 			tcp_send_dupack(sk, skb);
+		}
 		goto discard;
 	}
 
 	/* Step 2: check RST bit */
 	if (th->rst) {
-		tcp_reset(sk);
+		/* RFC 5961 3.2 :
+		 * If sequence number exactly matches RCV.NXT, then
+		 *     RESET the connection
+		 * else
+		 *     Send a challenge ACK
+		 */
+		if (TCP_SKB_CB(skb)->seq == tp->rcv_nxt)
+			tcp_reset(sk);
+		else
+			tcp_send_challenge_ack(sk);
 		goto discard;
 	}
 
-	/* ts_recent update must be made after we are sure that the packet
-	 * is in window.
-	 */
-	tcp_replace_ts_recent(tp, TCP_SKB_CB(skb)->seq);
-
 	/* step 3: check security and precedence [ignored] */
 
-	/* step 4: Check for a SYN in window. */
-	if (th->syn && !before(TCP_SKB_CB(skb)->seq, tp->rcv_nxt)) {
+	/* step 4: Check for a SYN
+	 * RFC 5691 4.2 : Send a challenge ack
+	 */
+	if (th->syn) {
+syn_challenge:
 		if (syn_inerr)
 			TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_INERRS);
-		NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPABORTONSYN);
-		tcp_reset(sk);
-		return -1;
+		NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPSYNCHALLENGE);
+		tcp_send_challenge_ack(sk);
+		goto discard;
 	}
 
-	return 1;
+	return true;
 
 discard:
 	__kfree_skb(skb);
-	return 0;
+	return false;
 }
 
 /*
@@ -5303,7 +5404,6 @@ int tcp_rcv_established(struct sock *sk, struct sk_buff *skb,
 			const struct tcphdr *th, unsigned int len)
 {
 	struct tcp_sock *tp = tcp_sk(sk);
-	int res;
 
 	/*
 	 *	Header prediction.
@@ -5388,7 +5488,9 @@ int tcp_rcv_established(struct sock *sk, struct sk_buff *skb,
 			if (tp->copied_seq == tp->rcv_nxt &&
 			    len - tcp_header_len <= tp->ucopy.len) {
 #ifdef CONFIG_NET_DMA
-				if (tcp_dma_try_early_copy(sk, skb, tcp_header_len)) {
+				if (tp->ucopy.task == current &&
+				    sock_owned_by_user(sk) &&
+				    tcp_dma_try_early_copy(sk, skb, tcp_header_len)) {
 					copied_early = 1;
 					eaten = 1;
 				}
@@ -5424,6 +5526,9 @@ int tcp_rcv_established(struct sock *sk, struct sk_buff *skb,
 				if (tcp_checksum_complete_user(sk, skb))
 					goto csum_error;
 
+				if ((int)skb->truesize > sk->sk_forward_alloc)
+					goto step5;
+
 				/* Predicted packet is in window by definition.
 				 * seq == rcv_nxt and rcv_wup <= rcv_nxt.
 				 * Hence, check seq<=rcv_wup reduces to:
@@ -5435,9 +5540,6 @@ int tcp_rcv_established(struct sock *sk, struct sk_buff *skb,
 
 				tcp_rcv_rtt_measure_ts(sk, skb);
 
-				if ((int)skb->truesize > sk->sk_forward_alloc)
-					goto step5;
-
 				NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPHPHITS);
 
 				/* Bulk data transfer: receiver */
@@ -5481,12 +5583,12 @@ slow_path:
 	 *	Standard slow path.
 	 */
 
-	res = tcp_validate_incoming(sk, skb, th, 1);
-	if (res <= 0)
-		return -res;
+	if (!tcp_validate_incoming(sk, skb, th, 1))
+		return 0;
 
 step5:
-	if (th->ack && tcp_ack(sk, skb, FLAG_SLOWPATH) < 0)
+	if (th->ack &&
+	    tcp_ack(sk, skb, FLAG_SLOWPATH | FLAG_UPDATE_TS_RECENT) < 0)
 		goto discard;
 
 	tcp_rcv_rtt_measure_ts(sk, skb);
@@ -5734,6 +5836,7 @@ discard:
 		}
 
 		tp->rcv_nxt = TCP_SKB_CB(skb)->seq + 1;
+		tp->copied_seq = tp->rcv_nxt;
 		tp->rcv_wup = TCP_SKB_CB(skb)->seq + 1;
 
 		/* RFC1323: The window in SYN & SYN/ACK segments is
@@ -5793,7 +5896,6 @@ int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb,
 	struct tcp_sock *tp = tcp_sk(sk);
 	struct inet_connection_sock *icsk = inet_csk(sk);
 	int queued = 0;
-	int res;
 
 	tp->rx_opt.saw_tstamp = 0;
 
@@ -5809,6 +5911,8 @@ int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb,
 			goto discard;
 
 		if (th->syn) {
+			if (th->fin)
+				goto discard;
 			if (icsk->icsk_af_ops->conn_request(sk, skb) < 0)
 				return 1;
 
@@ -5846,13 +5950,13 @@ int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb,
 		return 0;
 	}
 
-	res = tcp_validate_incoming(sk, skb, th, 0);
-	if (res <= 0)
-		return -res;
+	if (!tcp_validate_incoming(sk, skb, th, 0))
+		return 0;
 
 	/* step 5: check the ACK field */
 	if (th->ack) {
-		int acceptable = tcp_ack(sk, skb, FLAG_SLOWPATH) > 0;
+		int acceptable = tcp_ack(sk, skb, FLAG_SLOWPATH |
+						  FLAG_UPDATE_TS_RECENT) > 0;
 
 		switch (sk->sk_state) {
 		case TCP_SYN_RECV: