Merge Linus master into drm-next

The merge is clean, but the arm build fails afterwards,
due to API changes in the regulator tree.

I've included the patch into the merge to fix the build.

Signed-off-by: Dave Airlie <airlied@redhat.com>

1 files changed, 175 insertions, 43 deletions

diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index f501ac048366..a7ef679dd3ea 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -866,7 +866,7 @@ static void tcp_update_reordering(struct sock *sk, const int metric,
 /* This must be called before lost_out is incremented */
 static void tcp_verify_retransmit_hint(struct tcp_sock *tp, struct sk_buff *skb)
 {
-	if ((tp->retransmit_skb_hint == NULL) ||
+	if (!tp->retransmit_skb_hint ||
 	    before(TCP_SKB_CB(skb)->seq,
 		   TCP_SKB_CB(tp->retransmit_skb_hint)->seq))
 		tp->retransmit_skb_hint = skb;
@@ -1256,7 +1256,7 @@ static u8 tcp_sacktag_one(struct sock *sk,
 		fack_count += pcount;
 
 		/* Lost marker hint past SACKed? Tweak RFC3517 cnt */
-		if (!tcp_is_fack(tp) && (tp->lost_skb_hint != NULL) &&
+		if (!tcp_is_fack(tp) && tp->lost_skb_hint &&
 		    before(start_seq, TCP_SKB_CB(tp->lost_skb_hint)->seq))
 			tp->lost_cnt_hint += pcount;
 
@@ -1535,7 +1535,7 @@ static struct sk_buff *tcp_sacktag_walk(struct sk_buff *skb, struct sock *sk,
 		if (!before(TCP_SKB_CB(skb)->seq, end_seq))
 			break;
 
-		if ((next_dup != NULL) &&
+		if (next_dup  &&
 		    before(TCP_SKB_CB(skb)->seq, next_dup->end_seq)) {
 			in_sack = tcp_match_skb_to_sack(sk, skb,
 							next_dup->start_seq,
@@ -1551,7 +1551,7 @@ static struct sk_buff *tcp_sacktag_walk(struct sk_buff *skb, struct sock *sk,
 		if (in_sack <= 0) {
 			tmp = tcp_shift_skb_data(sk, skb, state,
 						 start_seq, end_seq, dup_sack);
-			if (tmp != NULL) {
+			if (tmp) {
 				if (tmp != skb) {
 					skb = tmp;
 					continue;
@@ -1614,7 +1614,7 @@ static struct sk_buff *tcp_maybe_skipping_dsack(struct sk_buff *skb,
 						struct tcp_sacktag_state *state,
 						u32 skip_to_seq)
 {
-	if (next_dup == NULL)
+	if (!next_dup)
 		return skb;
 
 	if (before(next_dup->start_seq, skip_to_seq)) {
@@ -1783,7 +1783,7 @@ tcp_sacktag_write_queue(struct sock *sk, const struct sk_buff *ack_skb,
 			if (tcp_highest_sack_seq(tp) == cache->end_seq) {
 				/* ...but better entrypoint exists! */
 				skb = tcp_highest_sack(sk);
-				if (skb == NULL)
+				if (!skb)
 					break;
 				state.fack_count = tp->fackets_out;
 				cache++;
@@ -1798,7 +1798,7 @@ tcp_sacktag_write_queue(struct sock *sk, const struct sk_buff *ack_skb,
 
 		if (!before(start_seq, tcp_highest_sack_seq(tp))) {
 			skb = tcp_highest_sack(sk);
-			if (skb == NULL)
+			if (!skb)
 				break;
 			state.fack_count = tp->fackets_out;
 		}
@@ -3099,17 +3099,15 @@ static int tcp_clean_rtx_queue(struct sock *sk, int prior_fackets,
 			if (sacked & TCPCB_SACKED_RETRANS)
 				tp->retrans_out -= acked_pcount;
 			flag |= FLAG_RETRANS_DATA_ACKED;
-		} else {
+		} else if (!(sacked & TCPCB_SACKED_ACKED)) {
 			last_ackt = skb->skb_mstamp;
 			WARN_ON_ONCE(last_ackt.v64 == 0);
 			if (!first_ackt.v64)
 				first_ackt = last_ackt;
 
-			if (!(sacked & TCPCB_SACKED_ACKED)) {
-				reord = min(pkts_acked, reord);
-				if (!after(scb->end_seq, tp->high_seq))
-					flag |= FLAG_ORIG_SACK_ACKED;
-			}
+			reord = min(pkts_acked, reord);
+			if (!after(scb->end_seq, tp->high_seq))
+				flag |= FLAG_ORIG_SACK_ACKED;
 		}
 
 		if (sacked & TCPCB_SACKED_ACKED)
@@ -3322,6 +3320,36 @@ static int tcp_ack_update_window(struct sock *sk, const struct sk_buff *skb, u32
 	return flag;
 }
 
+/* Return true if we're currently rate-limiting out-of-window ACKs and
+ * thus shouldn't send a dupack right now. We rate-limit dupacks in
+ * response to out-of-window SYNs or ACKs to mitigate ACK loops or DoS
+ * attacks that send repeated SYNs or ACKs for the same connection. To
+ * do this, we do not send a duplicate SYNACK or ACK if the remote
+ * endpoint is sending out-of-window SYNs or pure ACKs at a high rate.
+ */
+bool tcp_oow_rate_limited(struct net *net, const struct sk_buff *skb,
+			  int mib_idx, u32 *last_oow_ack_time)
+{
+	/* Data packets without SYNs are not likely part of an ACK loop. */
+	if ((TCP_SKB_CB(skb)->seq != TCP_SKB_CB(skb)->end_seq) &&
+	    !tcp_hdr(skb)->syn)
+		goto not_rate_limited;
+
+	if (*last_oow_ack_time) {
+		s32 elapsed = (s32)(tcp_time_stamp - *last_oow_ack_time);
+
+		if (0 <= elapsed && elapsed < sysctl_tcp_invalid_ratelimit) {
+			NET_INC_STATS_BH(net, mib_idx);
+			return true;	/* rate-limited: don't send yet! */
+		}
+	}
+
+	*last_oow_ack_time = tcp_time_stamp;
+
+not_rate_limited:
+	return false;	/* not rate-limited: go ahead, send dupack now! */
+}
+
 /* RFC 5961 7 [ACK Throttling] */
 static void tcp_send_challenge_ack(struct sock *sk, const struct sk_buff *skb)
 {
@@ -3573,6 +3601,23 @@ old_ack:
 	return 0;
 }
 
+static void tcp_parse_fastopen_option(int len, const unsigned char *cookie,
+				      bool syn, struct tcp_fastopen_cookie *foc,
+				      bool exp_opt)
+{
+	/* Valid only in SYN or SYN-ACK with an even length.  */
+	if (!foc || !syn || len < 0 || (len & 1))
+		return;
+
+	if (len >= TCP_FASTOPEN_COOKIE_MIN &&
+	    len <= TCP_FASTOPEN_COOKIE_MAX)
+		memcpy(foc->val, cookie, len);
+	else if (len != 0)
+		len = -1;
+	foc->len = len;
+	foc->exp = exp_opt;
+}
+
 /* 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
  * the fast version below fails.
@@ -3662,21 +3707,22 @@ void tcp_parse_options(const struct sk_buff *skb,
 				 */
 				break;
 #endif
+			case TCPOPT_FASTOPEN:
+				tcp_parse_fastopen_option(
+					opsize - TCPOLEN_FASTOPEN_BASE,
+					ptr, th->syn, foc, false);
+				break;
+
 			case TCPOPT_EXP:
 				/* Fast Open option shares code 254 using a
-				 * 16 bits magic number. It's valid only in
-				 * SYN or SYN-ACK with an even size.
+				 * 16 bits magic number.
 				 */
-				if (opsize < TCPOLEN_EXP_FASTOPEN_BASE ||
-				    get_unaligned_be16(ptr) != TCPOPT_FASTOPEN_MAGIC ||
-				    foc == NULL || !th->syn || (opsize & 1))
-					break;
-				foc->len = opsize - TCPOLEN_EXP_FASTOPEN_BASE;
-				if (foc->len >= TCP_FASTOPEN_COOKIE_MIN &&
-				    foc->len <= TCP_FASTOPEN_COOKIE_MAX)
-					memcpy(foc->val, ptr + 2, foc->len);
-				else if (foc->len != 0)
-					foc->len = -1;
+				if (opsize >= TCPOLEN_EXP_FASTOPEN_BASE &&
+				    get_unaligned_be16(ptr) ==
+				    TCPOPT_FASTOPEN_MAGIC)
+					tcp_parse_fastopen_option(opsize -
+						TCPOLEN_EXP_FASTOPEN_BASE,
+						ptr + 2, th->syn, foc, true);
 				break;
 
 			}
@@ -4640,7 +4686,7 @@ static void tcp_collapse_ofo_queue(struct sock *sk)
 	struct sk_buff *head;
 	u32 start, end;
 
-	if (skb == NULL)
+	if (!skb)
 		return;
 
 	start = TCP_SKB_CB(skb)->seq;
@@ -5095,7 +5141,7 @@ void tcp_rcv_established(struct sock *sk, struct sk_buff *skb,
 {
 	struct tcp_sock *tp = tcp_sk(sk);
 
-	if (unlikely(sk->sk_rx_dst == NULL))
+	if (unlikely(!sk->sk_rx_dst))
 		inet_csk(sk)->icsk_af_ops->sk_rx_dst_set(sk, skb);
 	/*
 	 *	Header prediction.
@@ -5292,7 +5338,7 @@ void tcp_finish_connect(struct sock *sk, struct sk_buff *skb)
 
 	tcp_set_state(sk, TCP_ESTABLISHED);
 
-	if (skb != NULL) {
+	if (skb) {
 		icsk->icsk_af_ops->sk_rx_dst_set(sk, skb);
 		security_inet_conn_established(sk, skb);
 	}
@@ -5330,8 +5376,8 @@ static bool tcp_rcv_fastopen_synack(struct sock *sk, struct sk_buff *synack,
 {
 	struct tcp_sock *tp = tcp_sk(sk);
 	struct sk_buff *data = tp->syn_data ? tcp_write_queue_head(sk) : NULL;
-	u16 mss = tp->rx_opt.mss_clamp;
-	bool syn_drop;
+	u16 mss = tp->rx_opt.mss_clamp, try_exp = 0;
+	bool syn_drop = false;
 
 	if (mss == tp->rx_opt.user_mss) {
 		struct tcp_options_received opt;
@@ -5343,16 +5389,25 @@ static bool tcp_rcv_fastopen_synack(struct sock *sk, struct sk_buff *synack,
 		mss = opt.mss_clamp;
 	}
 
-	if (!tp->syn_fastopen)  /* Ignore an unsolicited cookie */
+	if (!tp->syn_fastopen) {
+		/* Ignore an unsolicited cookie */
 		cookie->len = -1;
+	} else if (tp->total_retrans) {
+		/* SYN timed out and the SYN-ACK neither has a cookie nor
+		 * acknowledges data. Presumably the remote received only
+		 * the retransmitted (regular) SYNs: either the original
+		 * SYN-data or the corresponding SYN-ACK was dropped.
+		 */
+		syn_drop = (cookie->len < 0 && data);
+	} else if (cookie->len < 0 && !tp->syn_data) {
+		/* We requested a cookie but didn't get it. If we did not use
+		 * the (old) exp opt format then try so next time (try_exp=1).
+		 * Otherwise we go back to use the RFC7413 opt (try_exp=2).
+		 */
+		try_exp = tp->syn_fastopen_exp ? 2 : 1;
+	}
 
-	/* The SYN-ACK neither has cookie nor acknowledges the data. Presumably
-	 * the remote receives only the retransmitted (regular) SYNs: either
-	 * the original SYN-data or the corresponding SYN-ACK is lost.
-	 */
-	syn_drop = (cookie->len <= 0 && data && tp->total_retrans);
-
-	tcp_fastopen_cache_set(sk, mss, cookie, syn_drop);
+	tcp_fastopen_cache_set(sk, mss, cookie, syn_drop, try_exp);
 
 	if (data) { /* Retransmit unacked data in SYN */
 		tcp_for_write_queue_from(data, sk) {
@@ -5661,11 +5716,11 @@ int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb,
 	}
 
 	req = tp->fastopen_rsk;
-	if (req != NULL) {
+	if (req) {
 		WARN_ON_ONCE(sk->sk_state != TCP_SYN_RECV &&
 		    sk->sk_state != TCP_FIN_WAIT1);
 
-		if (tcp_check_req(sk, skb, req, NULL, true) == NULL)
+		if (!tcp_check_req(sk, skb, req, true))
 			goto discard;
 	}
 
@@ -5751,7 +5806,7 @@ int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb,
 		 * ACK we have received, this would have acknowledged
 		 * our SYNACK so stop the SYNACK timer.
 		 */
-		if (req != NULL) {
+		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
@@ -5913,6 +5968,80 @@ static void tcp_ecn_create_request(struct request_sock *req,
 		inet_rsk(req)->ecn_ok = 1;
 }
 
+static void tcp_openreq_init(struct request_sock *req,
+			     const struct tcp_options_received *rx_opt,
+			     struct sk_buff *skb, const struct sock *sk)
+{
+	struct inet_request_sock *ireq = inet_rsk(req);
+
+	req->rcv_wnd = 0;		/* So that tcp_send_synack() knows! */
+	req->cookie_ts = 0;
+	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 = tcp_time_stamp;
+	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;
+	ireq->tstamp_ok = rx_opt->tstamp_ok;
+	ireq->sack_ok = rx_opt->sack_ok;
+	ireq->snd_wscale = rx_opt->snd_wscale;
+	ireq->wscale_ok = rx_opt->wscale_ok;
+	ireq->acked = 0;
+	ireq->ecn_ok = 0;
+	ireq->ir_rmt_port = tcp_hdr(skb)->source;
+	ireq->ir_num = ntohs(tcp_hdr(skb)->dest);
+	ireq->ir_mark = inet_request_mark(sk, skb);
+}
+
+struct request_sock *inet_reqsk_alloc(const struct request_sock_ops *ops,
+				      struct sock *sk_listener)
+{
+	struct request_sock *req = reqsk_alloc(ops, sk_listener);
+
+	if (req) {
+		struct inet_request_sock *ireq = inet_rsk(req);
+
+		kmemcheck_annotate_bitfield(ireq, flags);
+		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));
+		ireq->ireq_family = sk_listener->sk_family;
+	}
+
+	return req;
+}
+EXPORT_SYMBOL(inet_reqsk_alloc);
+
+/*
+ * Return true if a syncookie should be sent
+ */
+static bool tcp_syn_flood_action(struct sock *sk,
+				 const struct sk_buff *skb,
+				 const char *proto)
+{
+	const char *msg = "Dropping request";
+	bool want_cookie = false;
+	struct listen_sock *lopt;
+
+#ifdef CONFIG_SYN_COOKIES
+	if (sysctl_tcp_syncookies) {
+		msg = "Sending cookies";
+		want_cookie = true;
+		NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPREQQFULLDOCOOKIES);
+	} else
+#endif
+		NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPREQQFULLDROP);
+
+	lopt = inet_csk(sk)->icsk_accept_queue.listen_opt;
+	if (!lopt->synflood_warned && sysctl_tcp_syncookies != 2) {
+		lopt->synflood_warned = 1;
+		pr_info("%s: Possible SYN flooding on port %d. %s.  Check SNMP counters.\n",
+			proto, ntohs(tcp_hdr(skb)->dest), msg);
+	}
+	return want_cookie;
+}
+
 int tcp_conn_request(struct request_sock_ops *rsk_ops,
 		     const struct tcp_request_sock_ops *af_ops,
 		     struct sock *sk, struct sk_buff *skb)
@@ -5950,7 +6079,7 @@ int tcp_conn_request(struct request_sock_ops *rsk_ops,
 		goto drop;
 	}
 
-	req = inet_reqsk_alloc(rsk_ops);
+	req = inet_reqsk_alloc(rsk_ops, sk);
 	if (!req)
 		goto drop;
 
@@ -5967,6 +6096,9 @@ int tcp_conn_request(struct request_sock_ops *rsk_ops,
 	tmp_opt.tstamp_ok = tmp_opt.saw_tstamp;
 	tcp_openreq_init(req, &tmp_opt, skb, sk);
 
+	/* Note: tcp_v6_init_req() might override ir_iif for link locals */
+	inet_rsk(req)->ir_iif = sk->sk_bound_dev_if;
+
 	af_ops->init_req(req, sk, skb);
 
 	if (security_inet_conn_request(sk, skb, req))
@@ -6039,7 +6171,7 @@ int tcp_conn_request(struct request_sock_ops *rsk_ops,
 		if (err || want_cookie)
 			goto drop_and_free;
 
-		tcp_rsk(req)->listener = NULL;
+		tcp_rsk(req)->tfo_listener = false;
 		af_ops->queue_hash_add(sk, req, TCP_TIMEOUT_INIT);
 	}