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 int rds_tcp_keepalive(struct socket *sock)
  42 {
  43         /* values below based on xs_udp_default_timeout */
  44         int keepidle = 5; /* send a probe 'keepidle' secs after last data */
  45         int keepcnt = 5; /* number of unack'ed probes before declaring dead */
  46         int keepalive = 1;
  47         int ret = 0;
  48
  49         ret = kernel_setsockopt(sock, SOL_SOCKET, SO_KEEPALIVE,
  50                                 (char *)&keepalive, sizeof(keepalive));
  51         if (ret < 0)
  52                 goto bail;
  53
  54         ret = kernel_setsockopt(sock, IPPROTO_TCP, TCP_KEEPCNT,
  55                                 (char *)&keepcnt, sizeof(keepcnt));
  56         if (ret < 0)
  57                 goto bail;
  58
  59         ret = kernel_setsockopt(sock, IPPROTO_TCP, TCP_KEEPIDLE,
  60                                 (char *)&keepidle, sizeof(keepidle));
  61         if (ret < 0)
  62                 goto bail;
  63
  64         /* KEEPINTVL is the interval between successive probes. We follow
  65          * the model in xs_tcp_finish_connecting() and re-use keepidle.
  66          */
  67         ret = kernel_setsockopt(sock, IPPROTO_TCP, TCP_KEEPINTVL,
  68                                 (char *)&keepidle, sizeof(keepidle));
  69 bail:
  70         return ret;
  71 }
  72
  73 int rds_tcp_accept_one(struct socket *sock)
  74 {
  75         struct socket *new_sock = NULL;
  76         struct rds_connection *conn;
  77         int ret;
  78         struct inet_sock *inet;
  79         struct rds_tcp_connection *rs_tcp = NULL;
  80         int conn_state;
  81         struct sock *nsk;
  82
  83         ret = sock_create_kern(sock_net(sock->sk), sock->sk->sk_family,
  84                                sock->sk->sk_type, sock->sk->sk_protocol,
  85                                &new_sock);
  86         if (ret)
  87                 goto out;
  88
  89         new_sock->type = sock->type;
  90         new_sock->ops = sock->ops;
  91         ret = sock->ops->accept(sock, new_sock, O_NONBLOCK);
  92         if (ret < 0)
  93                 goto out;
  94
  95         ret = rds_tcp_keepalive(new_sock);
  96         if (ret < 0)
  97                 goto out;
  98
  99         rds_tcp_tune(new_sock);
 100
 101         inet = inet_sk(new_sock->sk);
 102
 103         rdsdebug("accepted tcp %pI4:%u -> %pI4:%u\n",
 104                  &inet->inet_saddr, ntohs(inet->inet_sport),
 105                  &inet->inet_daddr, ntohs(inet->inet_dport));
 106
 107         conn = rds_conn_create(sock_net(sock->sk),
 108                                inet->inet_saddr, inet->inet_daddr,
 109                                &rds_tcp_transport, GFP_KERNEL);
 110         if (IS_ERR(conn)) {
 111                 ret = PTR_ERR(conn);
 112                 goto out;
 113         }
 114         /* An incoming SYN request came in, and TCP just accepted it.
 115          *
 116          * If the client reboots, this conn will need to be cleaned up.
 117          * rds_tcp_state_change() will do that cleanup
 118          */
 119         rs_tcp = (struct rds_tcp_connection *)conn->c_transport_data;
 120         rds_conn_transition(conn, RDS_CONN_DOWN, RDS_CONN_CONNECTING);
 121         mutex_lock(&rs_tcp->t_conn_lock);
 122         conn_state = rds_conn_state(conn);
 123         if (conn_state != RDS_CONN_CONNECTING && conn_state != RDS_CONN_UP)
 124                 goto rst_nsk;
 125         if (rs_tcp->t_sock) {
 126                 /* Need to resolve a duelling SYN between peers.
 127                  * We have an outstanding SYN to this peer, which may
 128                  * potentially have transitioned to the RDS_CONN_UP state,
 129                  * so we must quiesce any send threads before resetting
 130                  * c_transport_data.
 131                  */
 132                 wait_event(conn->c_waitq,
 133                            !test_bit(RDS_IN_XMIT, &conn->c_flags));
 134                 if (ntohl(inet->inet_saddr) < ntohl(inet->inet_daddr)) {
 135                         goto rst_nsk;
 136                 } else if (rs_tcp->t_sock) {
 137                         rds_tcp_restore_callbacks(rs_tcp->t_sock, rs_tcp);
 138                         conn->c_outgoing = 0;
 139                 }
 140         }
 141         rds_tcp_set_callbacks(new_sock, conn);
 142         rds_connect_complete(conn); /* marks RDS_CONN_UP */
 143         new_sock = NULL;
 144         ret = 0;
 145         goto out;
 146 rst_nsk:
 147         /* reset the newly returned accept sock and bail */
 148         nsk = new_sock->sk;
 149         rds_tcp_stats_inc(s_tcp_listen_closed_stale);
 150         nsk->sk_user_data = NULL;
 151         nsk->sk_prot->disconnect(nsk, 0);
 152         tcp_done(nsk);
 153         new_sock = NULL;
 154         ret = 0;
 155 out:
 156         if (rs_tcp)
 157                 mutex_unlock(&rs_tcp->t_conn_lock);
 158         if (new_sock)
 159                 sock_release(new_sock);
 160         return ret;
 161 }
 162
 163 void rds_tcp_listen_data_ready(struct sock *sk)
 164 {
 165         void (*ready)(struct sock *sk);
 166
 167         rdsdebug("listen data ready sk %p\n", sk);
 168
 169         read_lock(&sk->sk_callback_lock);
 170         ready = sk->sk_user_data;
 171         if (!ready) { /* check for teardown race */
 172                 ready = sk->sk_data_ready;
 173                 goto out;
 174         }
 175
 176         /*
 177          * ->sk_data_ready is also called for a newly established child socket
 178          * before it has been accepted and the accepter has set up their
 179          * data_ready.. we only want to queue listen work for our listening
 180          * socket
 181          */
 182         if (sk->sk_state == TCP_LISTEN)
 183                 rds_tcp_accept_work(sk);
 184
 185 out:
 186         read_unlock(&sk->sk_callback_lock);
 187         ready(sk);
 188 }
 189
 190 struct socket *rds_tcp_listen_init(struct net *net)
 191 {
 192         struct sockaddr_in sin;
 193         struct socket *sock = NULL;
 194         int ret;
 195
 196         ret = sock_create_kern(net, PF_INET, SOCK_STREAM, IPPROTO_TCP, &sock);
 197         if (ret < 0)
 198                 goto out;
 199
 200         sock->sk->sk_reuse = SK_CAN_REUSE;
 201         rds_tcp_nonagle(sock);
 202
 203         write_lock_bh(&sock->sk->sk_callback_lock);
 204         sock->sk->sk_user_data = sock->sk->sk_data_ready;
 205         sock->sk->sk_data_ready = rds_tcp_listen_data_ready;
 206         write_unlock_bh(&sock->sk->sk_callback_lock);
 207
 208         sin.sin_family = PF_INET;
 209         sin.sin_addr.s_addr = (__force u32)htonl(INADDR_ANY);
 210         sin.sin_port = (__force u16)htons(RDS_TCP_PORT);
 211
 212         ret = sock->ops->bind(sock, (struct sockaddr *)&sin, sizeof(sin));
 213         if (ret < 0)
 214                 goto out;
 215
 216         ret = sock->ops->listen(sock, 64);
 217         if (ret < 0)
 218                 goto out;
 219
 220         return sock;
 221 out:
 222         if (sock)
 223                 sock_release(sock);
 224         return NULL;
 225 }
 226
 227 void rds_tcp_listen_stop(struct socket *sock)
 228 {
 229         struct sock *sk;
 230
 231         if (!sock)
 232                 return;
 233
 234         sk = sock->sk;
 235
 236         /* serialize with and prevent further callbacks */
 237         lock_sock(sk);
 238         write_lock_bh(&sk->sk_callback_lock);
 239         if (sk->sk_user_data) {
 240                 sk->sk_data_ready = sk->sk_user_data;
 241                 sk->sk_user_data = NULL;
 242         }
 243         write_unlock_bh(&sk->sk_callback_lock);
 244         release_sock(sk);
 245
 246         /* wait for accepts to stop and close the socket */
 247         flush_workqueue(rds_wq);
 248         sock_release(sock);
 249 }