RDS: Add TCP transport to RDS

This code allows RDS to be tunneled over a TCP connection.

RDMA operations are disabled when using TCP transport,
but this frees RDS from the IB/RDMA stack dependency, and allows
it to be used with standard Ethernet adapters, or in a VM.

Signed-off-by: Andy Grover <andy.grover@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 319 insertions, 0 deletions

diff --git a/net/rds/tcp.c b/net/rds/tcp.c
new file mode 100644
index 000000000000..e0ac9009db1a
--- /dev/null
+++ b/net/rds/tcp.c
@@ -0,0 +1,319 @@
+/*
+ * 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 <linux/in.h>
+#include <net/tcp.h>
+
+#include "rds.h"
+#include "tcp.h"
+
+/* only for info exporting */
+static DEFINE_SPINLOCK(rds_tcp_tc_list_lock);
+static LIST_HEAD(rds_tcp_tc_list);
+unsigned int rds_tcp_tc_count;
+
+/* Track rds_tcp_connection structs so they can be cleaned up */
+static DEFINE_SPINLOCK(rds_tcp_conn_lock);
+static LIST_HEAD(rds_tcp_conn_list);
+
+static struct kmem_cache *rds_tcp_conn_slab;
+
+#define RDS_TCP_DEFAULT_BUFSIZE (128 * 1024)
+
+/* doing it this way avoids calling tcp_sk() */
+void rds_tcp_nonagle(struct socket *sock)
+{
+        mm_segment_t oldfs = get_fs();
+        int val = 1;
+
+        set_fs(KERNEL_DS);
+        sock->ops->setsockopt(sock, SOL_TCP, TCP_NODELAY, (char __user *)&val,
+                              sizeof(val));
+        set_fs(oldfs);
+}
+
+void rds_tcp_tune(struct socket *sock)
+{
+        struct sock *sk = sock->sk;
+
+        rds_tcp_nonagle(sock);
+
+        /*
+         * We're trying to saturate gigabit with the default,
+         * see svc_sock_setbufsize().
+         */
+        lock_sock(sk);
+        sk->sk_sndbuf = RDS_TCP_DEFAULT_BUFSIZE;
+        sk->sk_rcvbuf = RDS_TCP_DEFAULT_BUFSIZE;
+        sk->sk_userlocks |= SOCK_SNDBUF_LOCK|SOCK_RCVBUF_LOCK;
+        release_sock(sk);
+}
+
+u32 rds_tcp_snd_nxt(struct rds_tcp_connection *tc)
+{
+        return tcp_sk(tc->t_sock->sk)->snd_nxt;
+}
+
+u32 rds_tcp_snd_una(struct rds_tcp_connection *tc)
+{
+        return tcp_sk(tc->t_sock->sk)->snd_una;
+}
+
+void rds_tcp_restore_callbacks(struct socket *sock,
+                               struct rds_tcp_connection *tc)
+{
+        rdsdebug("restoring sock %p callbacks from tc %p\n", sock, tc);
+        write_lock_bh(&sock->sk->sk_callback_lock);
+
+        /* done under the callback_lock to serialize with write_space */
+        spin_lock(&rds_tcp_tc_list_lock);
+        list_del_init(&tc->t_list_item);
+        rds_tcp_tc_count--;
+        spin_unlock(&rds_tcp_tc_list_lock);
+
+        tc->t_sock = NULL;
+
+        sock->sk->sk_write_space = tc->t_orig_write_space;
+        sock->sk->sk_data_ready = tc->t_orig_data_ready;
+        sock->sk->sk_state_change = tc->t_orig_state_change;
+        sock->sk->sk_user_data = NULL;
+
+        write_unlock_bh(&sock->sk->sk_callback_lock);
+}
+
+/*
+ * This is the only path that sets tc->t_sock.  Send and receive trust that
+ * it is set.  The RDS_CONN_CONNECTED bit protects those paths from being
+ * called while it isn't set.
+ */
+void rds_tcp_set_callbacks(struct socket *sock, struct rds_connection *conn)
+{
+        struct rds_tcp_connection *tc = conn->c_transport_data;
+
+        rdsdebug("setting sock %p callbacks to tc %p\n", sock, tc);
+        write_lock_bh(&sock->sk->sk_callback_lock);
+
+        /* done under the callback_lock to serialize with write_space */
+        spin_lock(&rds_tcp_tc_list_lock);
+        list_add_tail(&tc->t_list_item, &rds_tcp_tc_list);
+        rds_tcp_tc_count++;
+        spin_unlock(&rds_tcp_tc_list_lock);
+
+        /* accepted sockets need our listen data ready undone */
+        if (sock->sk->sk_data_ready == rds_tcp_listen_data_ready)
+                sock->sk->sk_data_ready = sock->sk->sk_user_data;
+
+        tc->t_sock = sock;
+        tc->conn = conn;
+        tc->t_orig_data_ready = sock->sk->sk_data_ready;
+        tc->t_orig_write_space = sock->sk->sk_write_space;
+        tc->t_orig_state_change = sock->sk->sk_state_change;
+
+        sock->sk->sk_user_data = conn;
+        sock->sk->sk_data_ready = rds_tcp_data_ready;
+        sock->sk->sk_write_space = rds_tcp_write_space;
+        sock->sk->sk_state_change = rds_tcp_state_change;
+
+        write_unlock_bh(&sock->sk->sk_callback_lock);
+}
+
+static void rds_tcp_tc_info(struct socket *sock, unsigned int len,
+                            struct rds_info_iterator *iter,
+                            struct rds_info_lengths *lens)
+{
+        struct rds_info_tcp_socket tsinfo;
+        struct rds_tcp_connection *tc;
+        unsigned long flags;
+        struct sockaddr_in sin;
+        int sinlen;
+
+        spin_lock_irqsave(&rds_tcp_tc_list_lock, flags);
+
+        if (len / sizeof(tsinfo) < rds_tcp_tc_count)
+                goto out;
+
+        list_for_each_entry(tc, &rds_tcp_tc_list, t_list_item) {
+
+                sock->ops->getname(sock, (struct sockaddr *)&sin, &sinlen, 0);
+                tsinfo.local_addr = sin.sin_addr.s_addr;
+                tsinfo.local_port = sin.sin_port;
+                sock->ops->getname(sock, (struct sockaddr *)&sin, &sinlen, 1);
+                tsinfo.peer_addr = sin.sin_addr.s_addr;
+                tsinfo.peer_port = sin.sin_port;
+
+                tsinfo.hdr_rem = tc->t_tinc_hdr_rem;
+                tsinfo.data_rem = tc->t_tinc_data_rem;
+                tsinfo.last_sent_nxt = tc->t_last_sent_nxt;
+                tsinfo.last_expected_una = tc->t_last_expected_una;
+                tsinfo.last_seen_una = tc->t_last_seen_una;
+
+                rds_info_copy(iter, &tsinfo, sizeof(tsinfo));
+        }
+
+out:
+        lens->nr = rds_tcp_tc_count;
+        lens->each = sizeof(tsinfo);
+
+        spin_unlock_irqrestore(&rds_tcp_tc_list_lock, flags);
+}
+
+static int rds_tcp_laddr_check(__be32 addr)
+{
+        if (inet_addr_type(&init_net, addr) == RTN_LOCAL)
+                return 0;
+        return -EADDRNOTAVAIL;
+}
+
+static int rds_tcp_conn_alloc(struct rds_connection *conn, gfp_t gfp)
+{
+        struct rds_tcp_connection *tc;
+
+        tc = kmem_cache_alloc(rds_tcp_conn_slab, gfp);
+        if (tc == NULL)
+                return -ENOMEM;
+
+        tc->t_sock = NULL;
+        tc->t_tinc = NULL;
+        tc->t_tinc_hdr_rem = sizeof(struct rds_header);
+        tc->t_tinc_data_rem = 0;
+
+        conn->c_transport_data = tc;
+
+        spin_lock_irq(&rds_tcp_conn_lock);
+        list_add_tail(&tc->t_tcp_node, &rds_tcp_conn_list);
+        spin_unlock_irq(&rds_tcp_conn_lock);
+
+        rdsdebug("alloced tc %p\n", conn->c_transport_data);
+        return 0;
+}
+
+static void rds_tcp_conn_free(void *arg)
+{
+        struct rds_tcp_connection *tc = arg;
+        rdsdebug("freeing tc %p\n", tc);
+        kmem_cache_free(rds_tcp_conn_slab, tc);
+}
+
+static void rds_tcp_destroy_conns(void)
+{
+        struct rds_tcp_connection *tc, *_tc;
+        LIST_HEAD(tmp_list);
+
+        /* avoid calling conn_destroy with irqs off */
+        spin_lock_irq(&rds_tcp_conn_lock);
+        list_splice(&rds_tcp_conn_list, &tmp_list);
+        INIT_LIST_HEAD(&rds_tcp_conn_list);
+        spin_unlock_irq(&rds_tcp_conn_lock);
+
+        list_for_each_entry_safe(tc, _tc, &tmp_list, t_tcp_node) {
+                if (tc->conn->c_passive)
+                        rds_conn_destroy(tc->conn->c_passive);
+                rds_conn_destroy(tc->conn);
+        }
+}
+
+void rds_tcp_exit(void)
+{
+        rds_info_deregister_func(RDS_INFO_TCP_SOCKETS, rds_tcp_tc_info);
+        rds_tcp_listen_stop();
+        rds_tcp_destroy_conns();
+        rds_trans_unregister(&rds_tcp_transport);
+        rds_tcp_recv_exit();
+        kmem_cache_destroy(rds_tcp_conn_slab);
+}
+module_exit(rds_tcp_exit);
+
+struct rds_transport rds_tcp_transport = {
+        .laddr_check            = rds_tcp_laddr_check,
+        .xmit_prepare           = rds_tcp_xmit_prepare,
+        .xmit_complete          = rds_tcp_xmit_complete,
+        .xmit_cong_map          = rds_tcp_xmit_cong_map,
+        .xmit                   = rds_tcp_xmit,
+        .recv                   = rds_tcp_recv,
+        .conn_alloc             = rds_tcp_conn_alloc,
+        .conn_free              = rds_tcp_conn_free,
+        .conn_connect           = rds_tcp_conn_connect,
+        .conn_shutdown          = rds_tcp_conn_shutdown,
+        .inc_copy_to_user       = rds_tcp_inc_copy_to_user,
+        .inc_purge              = rds_tcp_inc_purge,
+        .inc_free               = rds_tcp_inc_free,
+        .stats_info_copy        = rds_tcp_stats_info_copy,
+        .exit                   = rds_tcp_exit,
+        .t_owner                = THIS_MODULE,
+        .t_name                 = "tcp",
+        .t_prefer_loopback      = 1,
+};
+
+int __init rds_tcp_init(void)
+{
+        int ret;
+
+        rds_tcp_conn_slab = kmem_cache_create("rds_tcp_connection",
+                                              sizeof(struct rds_tcp_connection),
+                                              0, 0, NULL);
+        if (rds_tcp_conn_slab == NULL) {
+                ret = -ENOMEM;
+                goto out;
+        }
+
+        ret = rds_tcp_recv_init();
+        if (ret)
+                goto out_slab;
+
+        ret = rds_trans_register(&rds_tcp_transport);
+        if (ret)
+                goto out_recv;
+
+        ret = rds_tcp_listen_init();
+        if (ret)
+                goto out_register;
+
+        rds_info_register_func(RDS_INFO_TCP_SOCKETS, rds_tcp_tc_info);
+
+        goto out;
+
+out_register:
+        rds_trans_unregister(&rds_tcp_transport);
+out_recv:
+        rds_tcp_recv_exit();
+out_slab:
+        kmem_cache_destroy(rds_tcp_conn_slab);
+out:
+        return ret;
+}
+module_init(rds_tcp_init);
+
+MODULE_AUTHOR("Oracle Corporation <rds-devel@oss.oracle.com>");
+MODULE_DESCRIPTION("RDS: TCP transport");
+MODULE_LICENSE("Dual BSD/GPL");
+