RDS: Socket interface

Implement the RDS (Reliable Datagram Sockets) interface.
Signed-off-by: Andy Grover <andy.grover@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/rds/bind.c

+/*
+ * Copyright (c) 2006 Oracle.  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 <net/sock.h>
+#include <linux/in.h>
+#include <linux/if_arp.h>
+#include "rds.h"
+
+/*
+ * XXX this probably still needs more work.. no INADDR_ANY, and rbtrees aren't
+ * particularly zippy.
+ *
+ * This is now called for every incoming frame so we arguably care much more
+ * about it than we used to.
+ */
+static DEFINE_SPINLOCK(rds_bind_lock);
+static struct rb_root rds_bind_tree = RB_ROOT;
+
+static struct rds_sock *rds_bind_tree_walk(__be32 addr, __be16 port,
+					   struct rds_sock *insert)
+{
+	struct rb_node **p = &rds_bind_tree.rb_node;
+	struct rb_node *parent = NULL;
+	struct rds_sock *rs;
+	u64 cmp;
+	u64 needle = ((u64)be32_to_cpu(addr) << 32) | be16_to_cpu(port);
+
+	while (*p) {
+		parent = *p;
+		rs = rb_entry(parent, struct rds_sock, rs_bound_node);
+
+		cmp = ((u64)be32_to_cpu(rs->rs_bound_addr) << 32) |
+		      be16_to_cpu(rs->rs_bound_port);
+
+		if (needle < cmp)
+			p = &(*p)->rb_left;
+		else if (needle > cmp)
+			p = &(*p)->rb_right;
+		else
+			return rs;
+	}
+
+	if (insert) {
+		rb_link_node(&insert->rs_bound_node, parent, p);
+		rb_insert_color(&insert->rs_bound_node, &rds_bind_tree);
+	}
+	return NULL;
+}
+
+/*
+ * Return the rds_sock bound at the given local address.
+ *
+ * The rx path can race with rds_release.  We notice if rds_release() has
+ * marked this socket and don't return a rs ref to the rx path.
+ */
+struct rds_sock *rds_find_bound(__be32 addr, __be16 port)
+{
+	struct rds_sock *rs;
+	unsigned long flags;
+
+	spin_lock_irqsave(&rds_bind_lock, flags);
+	rs = rds_bind_tree_walk(addr, port, NULL);
+	if (rs && !sock_flag(rds_rs_to_sk(rs), SOCK_DEAD))
+		rds_sock_addref(rs);
+	else
+		rs = NULL;
+	spin_unlock_irqrestore(&rds_bind_lock, flags);
+
+	rdsdebug("returning rs %p for %pI4:%u\n", rs, &addr,
+		ntohs(port));
+	return rs;
+}
+
+/* returns -ve errno or +ve port */
+static int rds_add_bound(struct rds_sock *rs, __be32 addr, __be16 *port)
+{
+	unsigned long flags;
+	int ret = -EADDRINUSE;
+	u16 rover, last;
+
+	if (*port != 0) {
+		rover = be16_to_cpu(*port);
+		last = rover;
+	} else {
+		rover = max_t(u16, net_random(), 2);
+		last = rover - 1;
+	}
+
+	spin_lock_irqsave(&rds_bind_lock, flags);
+
+	do {
+		if (rover == 0)
+			rover++;
+		if (rds_bind_tree_walk(addr, cpu_to_be16(rover), rs) == NULL) {
+			*port = cpu_to_be16(rover);
+			ret = 0;
+			break;
+		}
+	} while (rover++ != last);
+
+	if (ret == 0)  {
+		rs->rs_bound_addr = addr;
+		rs->rs_bound_port = *port;
+		rds_sock_addref(rs);
+
+		rdsdebug("rs %p binding to %pI4:%d\n",
+		  rs, &addr, (int)ntohs(*port));
+	}
+
+	spin_unlock_irqrestore(&rds_bind_lock, flags);
+
+	return ret;
+}
+
+void rds_remove_bound(struct rds_sock *rs)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&rds_bind_lock, flags);
+
+	if (rs->rs_bound_addr) {
+		rdsdebug("rs %p unbinding from %pI4:%d\n",
+		  rs, &rs->rs_bound_addr,
+		  ntohs(rs->rs_bound_port));
+
+		rb_erase(&rs->rs_bound_node, &rds_bind_tree);
+		rds_sock_put(rs);
+		rs->rs_bound_addr = 0;
+	}
+
+	spin_unlock_irqrestore(&rds_bind_lock, flags);
+}
+
+int rds_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
+{
+	struct sock *sk = sock->sk;
+	struct sockaddr_in *sin = (struct sockaddr_in *)uaddr;
+	struct rds_sock *rs = rds_sk_to_rs(sk);
+	struct rds_transport *trans;
+	int ret = 0;
+
+	lock_sock(sk);
+
+	if (addr_len != sizeof(struct sockaddr_in) ||
+	    sin->sin_family != AF_INET ||
+	    rs->rs_bound_addr ||
+	    sin->sin_addr.s_addr == htonl(INADDR_ANY)) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	ret = rds_add_bound(rs, sin->sin_addr.s_addr, &sin->sin_port);
+	if (ret)
+		goto out;
+
+	trans = rds_trans_get_preferred(sin->sin_addr.s_addr);
+	if (trans == NULL) {
+		ret = -EADDRNOTAVAIL;
+		rds_remove_bound(rs);
+		goto out;
+	}
+
+	rs->rs_transport = trans;
+	ret = 0;
+
+out:
+	release_sock(sk);
+	return ret;
+}