LXR linux/net/rds/tcp

   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/in.h>
  35#include <net/tcp.h>
  36
  37#include "rds.h"
  38#include "tcp.h"
  39
  40void rds_tcp_state_change(struct sock *sk)
  41{
  42        void (*state_change)(struct sock *sk);
  43        struct rds_conn_path *cp;
  44        struct rds_tcp_connection *tc;
  45
  46        read_lock_bh(&sk->sk_callback_lock);
  47        cp = sk->sk_user_data;
  48        if (!cp) {
  49                state_change = sk->sk_state_change;
  50                goto out;
  51        }
  52        tc = cp->cp_transport_data;
  53        state_change = tc->t_orig_state_change;
  54
  55        rdsdebug("sock %p state_change to %d\n", tc->t_sock, sk->sk_state);
  56
  57        switch (sk->sk_state) {
  58        /* ignore connecting sockets as they make progress */
  59        case TCP_SYN_SENT:
  60        case TCP_SYN_RECV:
  61                break;
  62        case TCP_ESTABLISHED:
  63                /* Force the peer to reconnect so that we have the
  64                 * TCP ports going from <smaller-ip>.<transient> to
  65                 * <larger-ip>.<RDS_TCP_PORT>. We avoid marking the
  66                 * RDS connection as RDS_CONN_UP until the reconnect,
  67                 * to avoid RDS datagram loss.
  68                 */
  69                if (!IS_CANONICAL(cp->cp_conn->c_laddr, cp->cp_conn->c_faddr) &&
  70                    rds_conn_path_transition(cp, RDS_CONN_CONNECTING,
  71                                             RDS_CONN_ERROR)) {
  72                        rds_conn_path_drop(cp, false);
  73                } else {
  74                        rds_connect_path_complete(cp, RDS_CONN_CONNECTING);
  75                }
  76                break;
  77        case TCP_CLOSE_WAIT:
  78        case TCP_CLOSE:
  79                rds_conn_path_drop(cp, false);
  80        default:
  81                break;
  82        }
  83out:
  84        read_unlock_bh(&sk->sk_callback_lock);
  85        state_change(sk);
  86}
  87
  88int rds_tcp_conn_path_connect(struct rds_conn_path *cp)
  89{
  90        struct socket *sock = NULL;
  91        struct sockaddr_in src, dest;
  92        int ret;
  93        struct rds_connection *conn = cp->cp_conn;
  94        struct rds_tcp_connection *tc = cp->cp_transport_data;
  95
  96        /* for multipath rds,we only trigger the connection after
  97         * the handshake probe has determined the number of paths.
  98         */
  99        if (cp->cp_index > 0 && cp->cp_conn->c_npaths < 2)
 100                return -EAGAIN;
 101
 102        mutex_lock(&tc->t_conn_path_lock);
 103
 104        if (rds_conn_path_up(cp)) {
 105                mutex_unlock(&tc->t_conn_path_lock);
 106                return 0;
 107        }
 108        ret = sock_create_kern(rds_conn_net(conn), PF_INET,
 109                               SOCK_STREAM, IPPROTO_TCP, &sock);
 110        if (ret < 0)
 111                goto out;
 112
 113        rds_tcp_tune(sock);
 114
 115        src.sin_family = AF_INET;
 116        src.sin_addr.s_addr = (__force u32)conn->c_laddr;
 117        src.sin_port = (__force u16)htons(0);
 118
 119        ret = sock->ops->bind(sock, (struct sockaddr *)&src, sizeof(src));
 120        if (ret) {
 121                rdsdebug("bind failed with %d at address %pI4\n",
 122                         ret, &conn->c_laddr);
 123                goto out;
 124        }
 125
 126        dest.sin_family = AF_INET;
 127        dest.sin_addr.s_addr = (__force u32)conn->c_faddr;
 128        dest.sin_port = (__force u16)htons(RDS_TCP_PORT);
 129
 130        /*
 131         * once we call connect() we can start getting callbacks and they
 132         * own the socket
 133         */
 134        rds_tcp_set_callbacks(sock, cp);
 135        ret = sock->ops->connect(sock, (struct sockaddr *)&dest, sizeof(dest),
 136                                 O_NONBLOCK);
 137
 138        rdsdebug("connect to address %pI4 returned %d\n", &conn->c_faddr, ret);
 139        if (ret == -EINPROGRESS)
 140                ret = 0;
 141        if (ret == 0) {
 142                rds_tcp_keepalive(sock);
 143                sock = NULL;
 144        } else {
 145                rds_tcp_restore_callbacks(sock, cp->cp_transport_data);
 146        }
 147
 148out:
 149        mutex_unlock(&tc->t_conn_path_lock);
 150        if (sock)
 151                sock_release(sock);
 152        return ret;
 153}
 154
 155/*
 156 * Before killing the tcp socket this needs to serialize with callbacks.  The
 157 * caller has already grabbed the sending sem so we're serialized with other
 158 * senders.
 159 *
 160 * TCP calls the callbacks with the sock lock so we hold it while we reset the
 161 * callbacks to those set by TCP.  Our callbacks won't execute again once we
 162 * hold the sock lock.
 163 */
 164void rds_tcp_conn_path_shutdown(struct rds_conn_path *cp)
 165{
 166        struct rds_tcp_connection *tc = cp->cp_transport_data;
 167        struct socket *sock = tc->t_sock;
 168
 169        rdsdebug("shutting down conn %p tc %p sock %p\n",
 170                 cp->cp_conn, tc, sock);
 171
 172        if (sock) {
 173                if (rds_destroy_pending(cp->cp_conn))
 174                        sock_no_linger(sock->sk);
 175                sock->ops->shutdown(sock, RCV_SHUTDOWN | SEND_SHUTDOWN);
 176                lock_sock(sock->sk);
 177                rds_tcp_restore_callbacks(sock, tc); /* tc->tc_sock = NULL */
 178
 179                release_sock(sock->sk);
 180                sock_release(sock);
 181        }
 182
 183        if (tc->t_tinc) {
 184                rds_inc_put(&tc->t_tinc->ti_inc);
 185                tc->t_tinc = NULL;
 186        }
 187        tc->t_tinc_hdr_rem = sizeof(struct rds_header);
 188        tc->t_tinc_data_rem = 0;
 189}
 190