net/rds/tcp_listen.c

   1 /*
   2  * Copyright (c) 2006 Oracle.  All rights reserved.
   3  *
   4  * This software is available to you under a choice of one of two
   5  * licenses.  You may choose to be licensed under the terms of the GNU
   6  * General Public License (GPL) Version 2, available from the file
   7  * COPYING in the main directory of this source tree, or the
   8  * OpenIB.org BSD license below:
   9  *
  10  *     Redistribution and use in source and binary forms, with or
  11  *     without modification, are permitted provided that the following
  12  *     conditions are met:
  13  *
  14  *      - Redistributions of source code must retain the above
  15  *        copyright notice, this list of conditions and the following
  16  *        disclaimer.
  17  *
  18  *      - Redistributions in binary form must reproduce the above
  19  *        copyright notice, this list of conditions and the following
  20  *        disclaimer in the documentation and/or other materials
  21  *        provided with the distribution.
  22  *
  23  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  24  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  25  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  26  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
  27  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
  28  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  29  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  30  * SOFTWARE.
  31  *
  32  */
  33 #include <linux/kernel.h>
  34 #include <linux/gfp.h>
  35 #include <linux/in.h>
  36 #include <net/tcp.h>
  37
  38 #include "rds.h"
  39 #include "tcp.h"
  40
  41 /*
  42  * cheesy, but simple..
  43  */
  44 static void rds_tcp_accept_worker(struct work_struct *work);
  45 static DECLARE_WORK(rds_tcp_listen_work, rds_tcp_accept_worker);
  46 static struct socket *rds_tcp_listen_sock;
  47
  48 static int rds_tcp_accept_one(struct socket *sock)
  49 {
  50         struct socket *new_sock = NULL;
  51         struct rds_connection *conn;
  52         int ret;
  53         struct inet_sock *inet;
  54
  55         ret = sock_create_lite(sock->sk->sk_family, sock->sk->sk_type,
  56                                sock->sk->sk_protocol, &new_sock);
  57         if (ret)
  58                 goto out;
  59
  60         new_sock->type = sock->type;
  61         new_sock->ops = sock->ops;
  62         ret = sock->ops->accept(sock, new_sock, O_NONBLOCK);
  63         if (ret < 0)
  64                 goto out;
  65
  66         rds_tcp_tune(new_sock);
  67
  68         inet = inet_sk(new_sock->sk);
  69
  70         rdsdebug("accepted tcp %pI4:%u -> %pI4:%u\n",
  71                  &inet->inet_saddr, ntohs(inet->inet_sport),
  72                  &inet->inet_daddr, ntohs(inet->inet_dport));
  73
  74         conn = rds_conn_create(inet->inet_saddr, inet->inet_daddr,
  75                                &rds_tcp_transport, GFP_KERNEL);
  76         if (IS_ERR(conn)) {
  77                 ret = PTR_ERR(conn);
  78                 goto out;
  79         }
  80
  81         /*
  82          * see the comment above rds_queue_delayed_reconnect()
  83          */
  84         if (!rds_conn_transition(conn, RDS_CONN_DOWN, RDS_CONN_CONNECTING)) {
  85                 if (rds_conn_state(conn) == RDS_CONN_UP)
  86                         rds_tcp_stats_inc(s_tcp_listen_closed_stale);
  87                 else
  88                         rds_tcp_stats_inc(s_tcp_connect_raced);
  89                 rds_conn_drop(conn);
  90                 ret = 0;
  91                 goto out;
  92         }
  93
  94         rds_tcp_set_callbacks(new_sock, conn);
  95         rds_connect_complete(conn);
  96         new_sock = NULL;
  97         ret = 0;
  98
  99 out:
 100         if (new_sock)
 101                 sock_release(new_sock);
 102         return ret;
 103 }
 104
 105 static void rds_tcp_accept_worker(struct work_struct *work)
 106 {
 107         while (rds_tcp_accept_one(rds_tcp_listen_sock) == 0)
 108                 cond_resched();
 109 }
 110
 111 void rds_tcp_listen_data_ready(struct sock *sk)
 112 {
 113         void (*ready)(struct sock *sk);
 114
 115         rdsdebug("listen data ready sk %p\n", sk);
 116
 117         read_lock(&sk->sk_callback_lock);
 118         ready = sk->sk_user_data;
 119         if (!ready) { /* check for teardown race */
 120                 ready = sk->sk_data_ready;
 121                 goto out;
 122         }
 123
 124         /*
 125          * ->sk_data_ready is also called for a newly established child socket
 126          * before it has been accepted and the accepter has set up their
 127          * data_ready.. we only want to queue listen work for our listening
 128          * socket
 129          */
 130         if (sk->sk_state == TCP_LISTEN)
 131                 queue_work(rds_wq, &rds_tcp_listen_work);
 132
 133 out:
 134         read_unlock(&sk->sk_callback_lock);
 135         ready(sk);
 136 }
 137
 138 int rds_tcp_listen_init(void)
 139 {
 140         struct sockaddr_in sin;
 141         struct socket *sock = NULL;
 142         int ret;
 143
 144         ret = sock_create(PF_INET, SOCK_STREAM, IPPROTO_TCP, &sock);
 145         if (ret < 0)
 146                 goto out;
 147
 148         sock->sk->sk_reuse = SK_CAN_REUSE;
 149         rds_tcp_nonagle(sock);
 150
 151         write_lock_bh(&sock->sk->sk_callback_lock);
 152         sock->sk->sk_user_data = sock->sk->sk_data_ready;
 153         sock->sk->sk_data_ready = rds_tcp_listen_data_ready;
 154         write_unlock_bh(&sock->sk->sk_callback_lock);
 155
 156         sin.sin_family = PF_INET,
 157         sin.sin_addr.s_addr = (__force u32)htonl(INADDR_ANY);
 158         sin.sin_port = (__force u16)htons(RDS_TCP_PORT);
 159
 160         ret = sock->ops->bind(sock, (struct sockaddr *)&sin, sizeof(sin));
 161         if (ret < 0)
 162                 goto out;
 163
 164         ret = sock->ops->listen(sock, 64);
 165         if (ret < 0)
 166                 goto out;
 167
 168         rds_tcp_listen_sock = sock;
 169         sock = NULL;
 170 out:
 171         if (sock)
 172                 sock_release(sock);
 173         return ret;
 174 }
 175
 176 void rds_tcp_listen_stop(void)
 177 {
 178         struct socket *sock = rds_tcp_listen_sock;
 179         struct sock *sk;
 180
 181         if (!sock)
 182                 return;
 183
 184         sk = sock->sk;
 185
 186         /* serialize with and prevent further callbacks */
 187         lock_sock(sk);
 188         write_lock_bh(&sk->sk_callback_lock);
 189         if (sk->sk_user_data) {
 190                 sk->sk_data_ready = sk->sk_user_data;
 191                 sk->sk_user_data = NULL;
 192         }
 193         write_unlock_bh(&sk->sk_callback_lock);
 194         release_sock(sk);
 195
 196         /* wait for accepts to stop and close the socket */
 197         flush_workqueue(rds_wq);
 198         sock_release(sock);
 199         rds_tcp_listen_sock = NULL;
 200 }