1 files changed, 95 insertions, 132 deletions

diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index 93898e093d4e..d8841a2f1569 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -324,7 +324,6 @@ void tcp_req_err(struct sock *sk, u32 seq)
 
 	if (seq != tcp_rsk(req)->snt_isn) {
 		NET_INC_STATS_BH(net, LINUX_MIB_OUTOFWINDOWICMPS);
-		reqsk_put(req);
 	} else {
 		/*
 		 * Still in SYN_RECV, just remove it silently.
@@ -332,9 +331,10 @@ void tcp_req_err(struct sock *sk, u32 seq)
 		 * created socket, and POSIX does not want network
 		 * errors returned from accept().
 		 */
-		NET_INC_STATS_BH(net, LINUX_MIB_LISTENDROPS);
 		inet_csk_reqsk_queue_drop(req->rsk_listener, req);
+		NET_INC_STATS_BH(net, LINUX_MIB_LISTENDROPS);
 	}
+	reqsk_put(req);
 }
 EXPORT_SYMBOL(tcp_req_err);
 
@@ -576,7 +576,7 @@ EXPORT_SYMBOL(tcp_v4_send_check);
  *	Exception: precedence violation. We do not implement it in any case.
  */
 
-static void tcp_v4_send_reset(struct sock *sk, struct sk_buff *skb)
+static void tcp_v4_send_reset(const struct sock *sk, struct sk_buff *skb)
 {
 	const struct tcphdr *th = tcp_hdr(skb);
 	struct {
@@ -795,7 +795,7 @@ static void tcp_v4_timewait_ack(struct sock *sk, struct sk_buff *skb)
 	inet_twsk_put(tw);
 }
 
-static void tcp_v4_reqsk_send_ack(struct sock *sk, struct sk_buff *skb,
+static void tcp_v4_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb,
 				  struct request_sock *req)
 {
 	/* sk->sk_state == TCP_LISTEN -> for regular TCP_SYN_RECV
@@ -803,7 +803,7 @@ static void tcp_v4_reqsk_send_ack(struct sock *sk, struct sk_buff *skb,
 	 */
 	tcp_v4_send_ack(skb, (sk->sk_state == TCP_LISTEN) ?
 			tcp_rsk(req)->snt_isn + 1 : tcp_sk(sk)->snd_nxt,
-			tcp_rsk(req)->rcv_nxt, req->rcv_wnd,
+			tcp_rsk(req)->rcv_nxt, req->rsk_rcv_wnd,
 			tcp_time_stamp,
 			req->ts_recent,
 			0,
@@ -818,11 +818,11 @@ static void tcp_v4_reqsk_send_ack(struct sock *sk, struct sk_buff *skb,
  *	This still operates on a request_sock only, not on a big
  *	socket.
  */
-static int tcp_v4_send_synack(struct sock *sk, struct dst_entry *dst,
+static int tcp_v4_send_synack(const struct sock *sk, struct dst_entry *dst,
 			      struct flowi *fl,
 			      struct request_sock *req,
-			      u16 queue_mapping,
-			      struct tcp_fastopen_cookie *foc)
+			      struct tcp_fastopen_cookie *foc,
+				  bool attach_req)
 {
 	const struct inet_request_sock *ireq = inet_rsk(req);
 	struct flowi4 fl4;
@@ -833,12 +833,11 @@ static int tcp_v4_send_synack(struct sock *sk, struct dst_entry *dst,
 	if (!dst && (dst = inet_csk_route_req(sk, &fl4, req)) == NULL)
 		return -1;
 
-	skb = tcp_make_synack(sk, dst, req, foc);
+	skb = tcp_make_synack(sk, dst, req, foc, attach_req);
 
 	if (skb) {
 		__tcp_v4_send_check(skb, ireq->ir_loc_addr, ireq->ir_rmt_addr);
 
-		skb_set_queue_mapping(skb, queue_mapping);
 		err = ip_build_and_send_pkt(skb, sk, ireq->ir_loc_addr,
 					    ireq->ir_rmt_addr,
 					    ireq->opt);
@@ -865,7 +864,7 @@ static void tcp_v4_reqsk_destructor(struct request_sock *req)
  */
 
 /* Find the Key structure for an address.  */
-struct tcp_md5sig_key *tcp_md5_do_lookup(struct sock *sk,
+struct tcp_md5sig_key *tcp_md5_do_lookup(const struct sock *sk,
 					 const union tcp_md5_addr *addr,
 					 int family)
 {
@@ -877,7 +876,7 @@ struct tcp_md5sig_key *tcp_md5_do_lookup(struct sock *sk,
 	/* caller either holds rcu_read_lock() or socket lock */
 	md5sig = rcu_dereference_check(tp->md5sig_info,
 				       sock_owned_by_user(sk) ||
-				       lockdep_is_held(&sk->sk_lock.slock));
+				       lockdep_is_held((spinlock_t *)&sk->sk_lock.slock));
 	if (!md5sig)
 		return NULL;
 #if IS_ENABLED(CONFIG_IPV6)
@@ -894,7 +893,7 @@ struct tcp_md5sig_key *tcp_md5_do_lookup(struct sock *sk,
 }
 EXPORT_SYMBOL(tcp_md5_do_lookup);
 
-struct tcp_md5sig_key *tcp_v4_md5_lookup(struct sock *sk,
+struct tcp_md5sig_key *tcp_v4_md5_lookup(const struct sock *sk,
 					 const struct sock *addr_sk)
 {
 	const union tcp_md5_addr *addr;
@@ -922,7 +921,8 @@ int tcp_md5_do_add(struct sock *sk, const union tcp_md5_addr *addr,
 	}
 
 	md5sig = rcu_dereference_protected(tp->md5sig_info,
-					   sock_owned_by_user(sk));
+					   sock_owned_by_user(sk) ||
+					   lockdep_is_held(&sk->sk_lock.slock));
 	if (!md5sig) {
 		md5sig = kmalloc(sizeof(*md5sig), gfp);
 		if (!md5sig)
@@ -1112,10 +1112,13 @@ clear_hash_noput:
 }
 EXPORT_SYMBOL(tcp_v4_md5_hash_skb);
 
+#endif
+
 /* Called with rcu_read_lock() */
-static bool tcp_v4_inbound_md5_hash(struct sock *sk,
+static bool tcp_v4_inbound_md5_hash(const struct sock *sk,
 				    const struct sk_buff *skb)
 {
+#ifdef CONFIG_TCP_MD5SIG
 	/*
 	 * This gets called for each TCP segment that arrives
 	 * so we want to be efficient.
@@ -1165,10 +1168,12 @@ static bool tcp_v4_inbound_md5_hash(struct sock *sk,
 		return true;
 	}
 	return false;
-}
 #endif
+	return false;
+}
 
-static void tcp_v4_init_req(struct request_sock *req, struct sock *sk_listener,
+static void tcp_v4_init_req(struct request_sock *req,
+			    const struct sock *sk_listener,
 			    struct sk_buff *skb)
 {
 	struct inet_request_sock *ireq = inet_rsk(req);
@@ -1179,7 +1184,8 @@ static void tcp_v4_init_req(struct request_sock *req, struct sock *sk_listener,
 	ireq->opt = tcp_v4_save_options(skb);
 }
 
-static struct dst_entry *tcp_v4_route_req(struct sock *sk, struct flowi *fl,
+static struct dst_entry *tcp_v4_route_req(const struct sock *sk,
+					  struct flowi *fl,
 					  const struct request_sock *req,
 					  bool *strict)
 {
@@ -1218,7 +1224,6 @@ static const struct tcp_request_sock_ops tcp_request_sock_ipv4_ops = {
 	.route_req	=	tcp_v4_route_req,
 	.init_seq	=	tcp_v4_init_sequence,
 	.send_synack	=	tcp_v4_send_synack,
-	.queue_hash_add =	inet_csk_reqsk_queue_hash_add,
 };
 
 int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
@@ -1241,9 +1246,11 @@ EXPORT_SYMBOL(tcp_v4_conn_request);
  * The three way handshake has completed - we got a valid synack -
  * now create the new socket.
  */
-struct sock *tcp_v4_syn_recv_sock(struct sock *sk, struct sk_buff *skb,
+struct sock *tcp_v4_syn_recv_sock(const struct sock *sk, struct sk_buff *skb,
 				  struct request_sock *req,
-				  struct dst_entry *dst)
+				  struct dst_entry *dst,
+				  struct request_sock *req_unhash,
+				  bool *own_req)
 {
 	struct inet_request_sock *ireq;
 	struct inet_sock *newinet;
@@ -1277,7 +1284,6 @@ struct sock *tcp_v4_syn_recv_sock(struct sock *sk, struct sk_buff *skb,
 	newinet->mc_ttl	      = ip_hdr(skb)->ttl;
 	newinet->rcv_tos      = ip_hdr(skb)->tos;
 	inet_csk(newsk)->icsk_ext_hdr_len = 0;
-	sk_set_txhash(newsk);
 	if (inet_opt)
 		inet_csk(newsk)->icsk_ext_hdr_len = inet_opt->opt.optlen;
 	newinet->inet_id = newtp->write_seq ^ jiffies;
@@ -1320,7 +1326,9 @@ struct sock *tcp_v4_syn_recv_sock(struct sock *sk, struct sk_buff *skb,
 
 	if (__inet_inherit_port(sk, newsk) < 0)
 		goto put_and_exit;
-	__inet_hash_nolisten(newsk, NULL);
+	*own_req = inet_ehash_nolisten(newsk, req_to_sk(req_unhash));
+	if (*own_req)
+		tcp_move_syn(newtp, req);
 
 	return newsk;
 
@@ -1338,34 +1346,11 @@ put_and_exit:
 }
 EXPORT_SYMBOL(tcp_v4_syn_recv_sock);
 
-static struct sock *tcp_v4_hnd_req(struct sock *sk, struct sk_buff *skb)
+static struct sock *tcp_v4_cookie_check(struct sock *sk, struct sk_buff *skb)
 {
+#ifdef CONFIG_SYN_COOKIES
 	const struct tcphdr *th = tcp_hdr(skb);
-	const struct iphdr *iph = ip_hdr(skb);
-	struct request_sock *req;
-	struct sock *nsk;
-
-	req = inet_csk_search_req(sk, th->source, iph->saddr, iph->daddr);
-	if (req) {
-		nsk = tcp_check_req(sk, skb, req, false);
-		if (!nsk || nsk == sk)
-			reqsk_put(req);
-		return nsk;
-	}
-
-	nsk = inet_lookup_established(sock_net(sk), &tcp_hashinfo, iph->saddr,
-			th->source, iph->daddr, th->dest, inet_iif(skb));
-
-	if (nsk) {
-		if (nsk->sk_state != TCP_TIME_WAIT) {
-			bh_lock_sock(nsk);
-			return nsk;
-		}
-		inet_twsk_put(inet_twsk(nsk));
-		return NULL;
-	}
 
-#ifdef CONFIG_SYN_COOKIES
 	if (!th->syn)
 		sk = cookie_v4_check(sk, skb);
 #endif
@@ -1373,7 +1358,7 @@ static struct sock *tcp_v4_hnd_req(struct sock *sk, struct sk_buff *skb)
 }
 
 /* The socket must have it's spinlock held when we get
- * here.
+ * here, unless it is a TCP_LISTEN socket.
  *
  * We have a potential double-lock case here, so even when
  * doing backlog processing we use the BH locking scheme.
@@ -1404,13 +1389,13 @@ int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb)
 		goto csum_err;
 
 	if (sk->sk_state == TCP_LISTEN) {
-		struct sock *nsk = tcp_v4_hnd_req(sk, skb);
+		struct sock *nsk = tcp_v4_cookie_check(sk, skb);
+
 		if (!nsk)
 			goto discard;
-
 		if (nsk != sk) {
 			sock_rps_save_rxhash(nsk, skb);
-			sk_mark_napi_id(sk, skb);
+			sk_mark_napi_id(nsk, skb);
 			if (tcp_child_process(sk, nsk, skb)) {
 				rsk = nsk;
 				goto reset;
@@ -1420,7 +1405,7 @@ int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb)
 	} else
 		sock_rps_save_rxhash(sk, skb);
 
-	if (tcp_rcv_state_process(sk, skb, tcp_hdr(skb), skb->len)) {
+	if (tcp_rcv_state_process(sk, skb)) {
 		rsk = sk;
 		goto reset;
 	}
@@ -1508,7 +1493,7 @@ bool tcp_prequeue(struct sock *sk, struct sk_buff *skb)
 	if (likely(sk->sk_rx_dst))
 		skb_dst_drop(skb);
 	else
-		skb_dst_force(skb);
+		skb_dst_force_safe(skb);
 
 	__skb_queue_tail(&tp->ucopy.prequeue, skb);
 	tp->ucopy.memory += skb->truesize;
@@ -1590,6 +1575,7 @@ int tcp_v4_rcv(struct sk_buff *skb)
 	TCP_SKB_CB(skb)->ip_dsfield = ipv4_get_dsfield(iph);
 	TCP_SKB_CB(skb)->sacked	 = 0;
 
+lookup:
 	sk = __inet_lookup_skb(&tcp_hashinfo, skb, th->source, th->dest);
 	if (!sk)
 		goto no_tcp_socket;
@@ -1598,6 +1584,33 @@ process:
 	if (sk->sk_state == TCP_TIME_WAIT)
 		goto do_time_wait;
 
+	if (sk->sk_state == TCP_NEW_SYN_RECV) {
+		struct request_sock *req = inet_reqsk(sk);
+		struct sock *nsk = NULL;
+
+		sk = req->rsk_listener;
+		if (tcp_v4_inbound_md5_hash(sk, skb))
+			goto discard_and_relse;
+		if (likely(sk->sk_state == TCP_LISTEN)) {
+			nsk = tcp_check_req(sk, skb, req, false);
+		} else {
+			inet_csk_reqsk_queue_drop_and_put(sk, req);
+			goto lookup;
+		}
+		if (!nsk) {
+			reqsk_put(req);
+			goto discard_it;
+		}
+		if (nsk == sk) {
+			sock_hold(sk);
+			reqsk_put(req);
+		} else if (tcp_child_process(sk, nsk, skb)) {
+			tcp_v4_send_reset(nsk, skb);
+			goto discard_it;
+		} else {
+			return 0;
+		}
+	}
 	if (unlikely(iph->ttl < inet_sk(sk)->min_ttl)) {
 		NET_INC_STATS_BH(net, LINUX_MIB_TCPMINTTLDROP);
 		goto discard_and_relse;
@@ -1606,25 +1619,23 @@ process:
 	if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
 		goto discard_and_relse;
 
-#ifdef CONFIG_TCP_MD5SIG
-	/*
-	 * We really want to reject the packet as early as possible
-	 * if:
-	 *  o We're expecting an MD5'd packet and this is no MD5 tcp option
-	 *  o There is an MD5 option and we're not expecting one
-	 */
 	if (tcp_v4_inbound_md5_hash(sk, skb))
 		goto discard_and_relse;
-#endif
 
 	nf_reset(skb);
 
 	if (sk_filter(sk, skb))
 		goto discard_and_relse;
 
-	sk_incoming_cpu_update(sk);
 	skb->dev = NULL;
 
+	if (sk->sk_state == TCP_LISTEN) {
+		ret = tcp_v4_do_rcv(sk, skb);
+		goto put_and_return;
+	}
+
+	sk_incoming_cpu_update(sk);
+
 	bh_lock_sock_nested(sk);
 	tcp_sk(sk)->segs_in += max_t(u16, 1, skb_shinfo(skb)->gso_segs);
 	ret = 0;
@@ -1639,6 +1650,7 @@ process:
 	}
 	bh_unlock_sock(sk);
 
+put_and_return:
 	sock_put(sk);
 
 	return ret;
@@ -1709,8 +1721,7 @@ void inet_sk_rx_dst_set(struct sock *sk, const struct sk_buff *skb)
 {
 	struct dst_entry *dst = skb_dst(skb);
 
-	if (dst) {
-		dst_hold(dst);
+	if (dst && dst_hold_safe(dst)) {
 		sk->sk_rx_dst = dst;
 		inet_sk(sk)->rx_dst_ifindex = skb->skb_iif;
 	}
@@ -1833,35 +1844,7 @@ static void *listening_get_next(struct seq_file *seq, void *cur)
 	++st->num;
 	++st->offset;
 
-	if (st->state == TCP_SEQ_STATE_OPENREQ) {
-		struct request_sock *req = cur;
-
-		icsk = inet_csk(st->syn_wait_sk);
-		req = req->dl_next;
-		while (1) {
-			while (req) {
-				if (req->rsk_ops->family == st->family) {
-					cur = req;
-					goto out;
-				}
-				req = req->dl_next;
-			}
-			if (++st->sbucket >= icsk->icsk_accept_queue.listen_opt->nr_table_entries)
-				break;
-get_req:
-			req = icsk->icsk_accept_queue.listen_opt->syn_table[st->sbucket];
-		}
-		sk	  = sk_nulls_next(st->syn_wait_sk);
-		st->state = TCP_SEQ_STATE_LISTENING;
-		spin_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
-	} else {
-		icsk = inet_csk(sk);
-		spin_lock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
-		if (reqsk_queue_len(&icsk->icsk_accept_queue))
-			goto start_req;
-		spin_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
-		sk = sk_nulls_next(sk);
-	}
+	sk = sk_nulls_next(sk);
 get_sk:
 	sk_nulls_for_each_from(sk, node) {
 		if (!net_eq(sock_net(sk), net))
@@ -1871,16 +1854,6 @@ get_sk:
 			goto out;
 		}
 		icsk = inet_csk(sk);
-		spin_lock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
-		if (reqsk_queue_len(&icsk->icsk_accept_queue)) {
-start_req:
-			st->uid		= sock_i_uid(sk);
-			st->syn_wait_sk = sk;
-			st->state	= TCP_SEQ_STATE_OPENREQ;
-			st->sbucket	= 0;
-			goto get_req;
-		}
-		spin_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
 	}
 	spin_unlock_bh(&ilb->lock);
 	st->offset = 0;
@@ -2012,7 +1985,6 @@ static void *tcp_seek_last_pos(struct seq_file *seq)
 	void *rc = NULL;
 
 	switch (st->state) {
-	case TCP_SEQ_STATE_OPENREQ:
 	case TCP_SEQ_STATE_LISTENING:
 		if (st->bucket >= INET_LHTABLE_SIZE)
 			break;
@@ -2071,7 +2043,6 @@ static void *tcp_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 	}
 
 	switch (st->state) {
-	case TCP_SEQ_STATE_OPENREQ:
 	case TCP_SEQ_STATE_LISTENING:
 		rc = listening_get_next(seq, v);
 		if (!rc) {
@@ -2096,11 +2067,6 @@ static void tcp_seq_stop(struct seq_file *seq, void *v)
 	struct tcp_iter_state *st = seq->private;
 
 	switch (st->state) {
-	case TCP_SEQ_STATE_OPENREQ:
-		if (v) {
-			struct inet_connection_sock *icsk = inet_csk(st->syn_wait_sk);
-			spin_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
-		}
 	case TCP_SEQ_STATE_LISTENING:
 		if (v != SEQ_START_TOKEN)
 			spin_unlock_bh(&tcp_hashinfo.listening_hash[st->bucket].lock);
@@ -2154,7 +2120,7 @@ void tcp_proc_unregister(struct net *net, struct tcp_seq_afinfo *afinfo)
 EXPORT_SYMBOL(tcp_proc_unregister);
 
 static void get_openreq4(const struct request_sock *req,
-			 struct seq_file *f, int i, kuid_t uid)
+			 struct seq_file *f, int i)
 {
 	const struct inet_request_sock *ireq = inet_rsk(req);
 	long delta = req->rsk_timer.expires - jiffies;
@@ -2171,7 +2137,8 @@ static void get_openreq4(const struct request_sock *req,
 		1,    /* timers active (only the expire timer) */
 		jiffies_delta_to_clock_t(delta),
 		req->num_timeout,
-		from_kuid_munged(seq_user_ns(f), uid),
+		from_kuid_munged(seq_user_ns(f),
+				 sock_i_uid(req->rsk_listener)),
 		0,  /* non standard timer */
 		0, /* open_requests have no inode */
 		0,
@@ -2185,12 +2152,13 @@ static void get_tcp4_sock(struct sock *sk, struct seq_file *f, int i)
 	const struct tcp_sock *tp = tcp_sk(sk);
 	const struct inet_connection_sock *icsk = inet_csk(sk);
 	const struct inet_sock *inet = inet_sk(sk);
-	struct fastopen_queue *fastopenq = icsk->icsk_accept_queue.fastopenq;
+	const struct fastopen_queue *fastopenq = &icsk->icsk_accept_queue.fastopenq;
 	__be32 dest = inet->inet_daddr;
 	__be32 src = inet->inet_rcv_saddr;
 	__u16 destp = ntohs(inet->inet_dport);
 	__u16 srcp = ntohs(inet->inet_sport);
 	int rx_queue;
+	int state;
 
 	if (icsk->icsk_pending == ICSK_TIME_RETRANS ||
 	    icsk->icsk_pending == ICSK_TIME_EARLY_RETRANS ||
@@ -2208,17 +2176,18 @@ static void get_tcp4_sock(struct sock *sk, struct seq_file *f, int i)
 		timer_expires = jiffies;
 	}
 
-	if (sk->sk_state == TCP_LISTEN)
+	state = sk_state_load(sk);
+	if (state == TCP_LISTEN)
 		rx_queue = sk->sk_ack_backlog;
 	else
-		/*
-		 * because we dont lock socket, we might find a transient negative value
+		/* Because we don't lock the socket,
+		 * we might find a transient negative value.
 		 */
 		rx_queue = max_t(int, tp->rcv_nxt - tp->copied_seq, 0);
 
 	seq_printf(f, "%4d: %08X:%04X %08X:%04X %02X %08X:%08X %02X:%08lX "
 			"%08X %5u %8d %lu %d %pK %lu %lu %u %u %d",
-		i, src, srcp, dest, destp, sk->sk_state,
+		i, src, srcp, dest, destp, state,
 		tp->write_seq - tp->snd_una,
 		rx_queue,
 		timer_active,
@@ -2232,8 +2201,8 @@ static void get_tcp4_sock(struct sock *sk, struct seq_file *f, int i)
 		jiffies_to_clock_t(icsk->icsk_ack.ato),
 		(icsk->icsk_ack.quick << 1) | icsk->icsk_ack.pingpong,
 		tp->snd_cwnd,
-		sk->sk_state == TCP_LISTEN ?
-		    (fastopenq ? fastopenq->max_qlen : 0) :
+		state == TCP_LISTEN ?
+		    fastopenq->max_qlen :
 		    (tcp_in_initial_slowstart(tp) ? -1 : tp->snd_ssthresh));
 }
 
@@ -2272,18 +2241,12 @@ static int tcp4_seq_show(struct seq_file *seq, void *v)
 	}
 	st = seq->private;
 
-	switch (st->state) {
-	case TCP_SEQ_STATE_LISTENING:
-	case TCP_SEQ_STATE_ESTABLISHED:
-		if (sk->sk_state == TCP_TIME_WAIT)
-			get_timewait4_sock(v, seq, st->num);
-		else
-			get_tcp4_sock(v, seq, st->num);
-		break;
-	case TCP_SEQ_STATE_OPENREQ:
-		get_openreq4(v, seq, st->num, st->uid);
-		break;
-	}
+	if (sk->sk_state == TCP_TIME_WAIT)
+		get_timewait4_sock(v, seq, st->num);
+	else if (sk->sk_state == TCP_NEW_SYN_RECV)
+		get_openreq4(v, seq, st->num);
+	else
+		get_tcp4_sock(v, seq, st->num);
 out:
 	seq_pad(seq, '\n');
 	return 0;