1 files changed, 348 insertions, 0 deletions
diff --git a/net/rds/tcp_listen.c b/net/rds/tcp_listen.c
new file mode 100644
index 000000000..b576bd252
--- /dev/null
+++ b/net/rds/tcp_listen.c
@@ -0,0 +1,348 @@
+/*
+ * Copyright (c) 2006, 2018 Oracle and/or its affiliates. All rights reserved.
+ *
+ * This software is available to you under a choice of one of two
+ * licenses.  You may choose to be licensed under the terms of the GNU
+ * General Public License (GPL) Version 2, available from the file
+ * COPYING in the main directory of this source tree, or the
+ * OpenIB.org BSD license below:
+ *
+ *     Redistribution and use in source and binary forms, with or
+ *     without modification, are permitted provided that the following
+ *     conditions are met:
+ *
+ *      - Redistributions of source code must retain the above
+ *        copyright notice, this list of conditions and the following
+ *        disclaimer.
+ *
+ *      - Redistributions in binary form must reproduce the above
+ *        copyright notice, this list of conditions and the following
+ *        disclaimer in the documentation and/or other materials
+ *        provided with the distribution.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ *
+ */
+#include <linux/kernel.h>
+#include <linux/gfp.h>
+#include <linux/in.h>
+#include <net/tcp.h>
+
+#include "rds.h"
+#include "tcp.h"
+
+void rds_tcp_keepalive(struct socket *sock)
+{
+	/* values below based on xs_udp_default_timeout */
+	int keepidle = 5; /* send a probe 'keepidle' secs after last data */
+	int keepcnt = 5; /* number of unack'ed probes before declaring dead */
+
+	sock_set_keepalive(sock->sk);
+	tcp_sock_set_keepcnt(sock->sk, keepcnt);
+	tcp_sock_set_keepidle(sock->sk, keepidle);
+	/* KEEPINTVL is the interval between successive probes. We follow
+	 * the model in xs_tcp_finish_connecting() and re-use keepidle.
+	 */
+	tcp_sock_set_keepintvl(sock->sk, keepidle);
+}
+
+/* rds_tcp_accept_one_path(): if accepting on cp_index > 0, make sure the
+ * client's ipaddr < server's ipaddr. Otherwise, close the accepted
+ * socket and force a reconneect from smaller -> larger ip addr. The reason
+ * we special case cp_index 0 is to allow the rds probe ping itself to itself
+ * get through efficiently.
+ * Since reconnects are only initiated from the node with the numerically
+ * smaller ip address, we recycle conns in RDS_CONN_ERROR on the passive side
+ * by moving them to CONNECTING in this function.
+ */
+static
+struct rds_tcp_connection *rds_tcp_accept_one_path(struct rds_connection *conn)
+{
+	int i;
+	int npaths = max_t(int, 1, conn->c_npaths);
+
+	/* for mprds, all paths MUST be initiated by the peer
+	 * with the smaller address.
+	 */
+	if (rds_addr_cmp(&conn->c_faddr, &conn->c_laddr) >= 0) {
+		/* Make sure we initiate at least one path if this
+		 * has not already been done; rds_start_mprds() will
+		 * take care of additional paths, if necessary.
+		 */
+		if (npaths == 1)
+			rds_conn_path_connect_if_down(&conn->c_path[0]);
+		return NULL;
+	}
+
+	for (i = 0; i < npaths; i++) {
+		struct rds_conn_path *cp = &conn->c_path[i];
+
+		if (rds_conn_path_transition(cp, RDS_CONN_DOWN,
+					     RDS_CONN_CONNECTING) ||
+		    rds_conn_path_transition(cp, RDS_CONN_ERROR,
+					     RDS_CONN_CONNECTING)) {
+			return cp->cp_transport_data;
+		}
+	}
+	return NULL;
+}
+
+int rds_tcp_accept_one(struct socket *sock)
+{
+	struct socket *new_sock = NULL;
+	struct rds_connection *conn;
+	int ret;
+	struct inet_sock *inet;
+	struct rds_tcp_connection *rs_tcp = NULL;
+	int conn_state;
+	struct rds_conn_path *cp;
+	struct in6_addr *my_addr, *peer_addr;
+#if !IS_ENABLED(CONFIG_IPV6)
+	struct in6_addr saddr, daddr;
+#endif
+	int dev_if = 0;
+
+	if (!sock) /* module unload or netns delete in progress */
+		return -ENETUNREACH;
+
+	ret = sock_create_lite(sock->sk->sk_family,
+			       sock->sk->sk_type, sock->sk->sk_protocol,
+			       &new_sock);
+	if (ret)
+		goto out;
+
+	ret = sock->ops->accept(sock, new_sock, O_NONBLOCK, true);
+	if (ret < 0)
+		goto out;
+
+	/* sock_create_lite() does not get a hold on the owner module so we
+	 * need to do it here.  Note that sock_release() uses sock->ops to
+	 * determine if it needs to decrement the reference count.  So set
+	 * sock->ops after calling accept() in case that fails.  And there's
+	 * no need to do try_module_get() as the listener should have a hold
+	 * already.
+	 */
+	new_sock->ops = sock->ops;
+	__module_get(new_sock->ops->owner);
+
+	rds_tcp_keepalive(new_sock);
+	if (!rds_tcp_tune(new_sock)) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	inet = inet_sk(new_sock->sk);
+
+#if IS_ENABLED(CONFIG_IPV6)
+	my_addr = &new_sock->sk->sk_v6_rcv_saddr;
+	peer_addr = &new_sock->sk->sk_v6_daddr;
+#else
+	ipv6_addr_set_v4mapped(inet->inet_saddr, &saddr);
+	ipv6_addr_set_v4mapped(inet->inet_daddr, &daddr);
+	my_addr = &saddr;
+	peer_addr = &daddr;
+#endif
+	rdsdebug("accepted family %d tcp %pI6c:%u -> %pI6c:%u\n",
+		 sock->sk->sk_family,
+		 my_addr, ntohs(inet->inet_sport),
+		 peer_addr, ntohs(inet->inet_dport));
+
+#if IS_ENABLED(CONFIG_IPV6)
+	/* sk_bound_dev_if is not set if the peer address is not link local
+	 * address.  In this case, it happens that mcast_oif is set.  So
+	 * just use it.
+	 */
+	if ((ipv6_addr_type(my_addr) & IPV6_ADDR_LINKLOCAL) &&
+	    !(ipv6_addr_type(peer_addr) & IPV6_ADDR_LINKLOCAL)) {
+		struct ipv6_pinfo *inet6;
+
+		inet6 = inet6_sk(new_sock->sk);
+		dev_if = inet6->mcast_oif;
+	} else {
+		dev_if = new_sock->sk->sk_bound_dev_if;
+	}
+#endif
+
+	if (!rds_tcp_laddr_check(sock_net(sock->sk), peer_addr, dev_if)) {
+		/* local address connection is only allowed via loopback */
+		ret = -EOPNOTSUPP;
+		goto out;
+	}
+
+	conn = rds_conn_create(sock_net(sock->sk),
+			       my_addr, peer_addr,
+			       &rds_tcp_transport, 0, GFP_KERNEL, dev_if);
+
+	if (IS_ERR(conn)) {
+		ret = PTR_ERR(conn);
+		goto out;
+	}
+	/* An incoming SYN request came in, and TCP just accepted it.
+	 *
+	 * If the client reboots, this conn will need to be cleaned up.
+	 * rds_tcp_state_change() will do that cleanup
+	 */
+	rs_tcp = rds_tcp_accept_one_path(conn);
+	if (!rs_tcp)
+		goto rst_nsk;
+	mutex_lock(&rs_tcp->t_conn_path_lock);
+	cp = rs_tcp->t_cpath;
+	conn_state = rds_conn_path_state(cp);
+	WARN_ON(conn_state == RDS_CONN_UP);
+	if (conn_state != RDS_CONN_CONNECTING && conn_state != RDS_CONN_ERROR)
+		goto rst_nsk;
+	if (rs_tcp->t_sock) {
+		/* Duelling SYN has been handled in rds_tcp_accept_one() */
+		rds_tcp_reset_callbacks(new_sock, cp);
+		/* rds_connect_path_complete() marks RDS_CONN_UP */
+		rds_connect_path_complete(cp, RDS_CONN_RESETTING);
+	} else {
+		rds_tcp_set_callbacks(new_sock, cp);
+		rds_connect_path_complete(cp, RDS_CONN_CONNECTING);
+	}
+	new_sock = NULL;
+	ret = 0;
+	if (conn->c_npaths == 0)
+		rds_send_ping(cp->cp_conn, cp->cp_index);
+	goto out;
+rst_nsk:
+	/* reset the newly returned accept sock and bail.
+	 * It is safe to set linger on new_sock because the RDS connection
+	 * has not been brought up on new_sock, so no RDS-level data could
+	 * be pending on it. By setting linger, we achieve the side-effect
+	 * of avoiding TIME_WAIT state on new_sock.
+	 */
+	sock_no_linger(new_sock->sk);
+	kernel_sock_shutdown(new_sock, SHUT_RDWR);
+	ret = 0;
+out:
+	if (rs_tcp)
+		mutex_unlock(&rs_tcp->t_conn_path_lock);
+	if (new_sock)
+		sock_release(new_sock);
+	return ret;
+}
+
+void rds_tcp_listen_data_ready(struct sock *sk)
+{
+	void (*ready)(struct sock *sk);
+
+	rdsdebug("listen data ready sk %p\n", sk);
+
+	read_lock_bh(&sk->sk_callback_lock);
+	ready = sk->sk_user_data;
+	if (!ready) { /* check for teardown race */
+		ready = sk->sk_data_ready;
+		goto out;
+	}
+
+	/*
+	 * ->sk_data_ready is also called for a newly established child socket
+	 * before it has been accepted and the accepter has set up their
+	 * data_ready.. we only want to queue listen work for our listening
+	 * socket
+	 *
+	 * (*ready)() may be null if we are racing with netns delete, and
+	 * the listen socket is being torn down.
+	 */
+	if (sk->sk_state == TCP_LISTEN)
+		rds_tcp_accept_work(sk);
+	else
+		ready = rds_tcp_listen_sock_def_readable(sock_net(sk));
+
+out:
+	read_unlock_bh(&sk->sk_callback_lock);
+	if (ready)
+		ready(sk);
+}
+
+struct socket *rds_tcp_listen_init(struct net *net, bool isv6)
+{
+	struct socket *sock = NULL;
+	struct sockaddr_storage ss;
+	struct sockaddr_in6 *sin6;
+	struct sockaddr_in *sin;
+	int addr_len;
+	int ret;
+
+	ret = sock_create_kern(net, isv6 ? PF_INET6 : PF_INET, SOCK_STREAM,
+			       IPPROTO_TCP, &sock);
+	if (ret < 0) {
+		rdsdebug("could not create %s listener socket: %d\n",
+			 isv6 ? "IPv6" : "IPv4", ret);
+		goto out;
+	}
+
+	sock->sk->sk_reuse = SK_CAN_REUSE;
+	tcp_sock_set_nodelay(sock->sk);
+
+	write_lock_bh(&sock->sk->sk_callback_lock);
+	sock->sk->sk_user_data = sock->sk->sk_data_ready;
+	sock->sk->sk_data_ready = rds_tcp_listen_data_ready;
+	write_unlock_bh(&sock->sk->sk_callback_lock);
+
+	if (isv6) {
+		sin6 = (struct sockaddr_in6 *)&ss;
+		sin6->sin6_family = PF_INET6;
+		sin6->sin6_addr = in6addr_any;
+		sin6->sin6_port = (__force u16)htons(RDS_TCP_PORT);
+		sin6->sin6_scope_id = 0;
+		sin6->sin6_flowinfo = 0;
+		addr_len = sizeof(*sin6);
+	} else {
+		sin = (struct sockaddr_in *)&ss;
+		sin->sin_family = PF_INET;
+		sin->sin_addr.s_addr = INADDR_ANY;
+		sin->sin_port = (__force u16)htons(RDS_TCP_PORT);
+		addr_len = sizeof(*sin);
+	}
+
+	ret = kernel_bind(sock, (struct sockaddr *)&ss, addr_len);
+	if (ret < 0) {
+		rdsdebug("could not bind %s listener socket: %d\n",
+			 isv6 ? "IPv6" : "IPv4", ret);
+		goto out;
+	}
+
+	ret = sock->ops->listen(sock, 64);
+	if (ret < 0)
+		goto out;
+
+	return sock;
+out:
+	if (sock)
+		sock_release(sock);
+	return NULL;
+}
+
+void rds_tcp_listen_stop(struct socket *sock, struct work_struct *acceptor)
+{
+	struct sock *sk;
+
+	if (!sock)
+		return;
+
+	sk = sock->sk;
+
+	/* serialize with and prevent further callbacks */
+	lock_sock(sk);
+	write_lock_bh(&sk->sk_callback_lock);
+	if (sk->sk_user_data) {
+		sk->sk_data_ready = sk->sk_user_data;
+		sk->sk_user_data = NULL;
+	}
+	write_unlock_bh(&sk->sk_callback_lock);
+	release_sock(sk);
+
+	/* wait for accepts to stop and close the socket */
+	flush_workqueue(rds_wq);
+	flush_work(acceptor);
+	sock_release(sock);
+}