net/rds/tcp_connect.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/in.h>
  35 #include <net/tcp.h>
  36
  37 #include "rds.h"
  38 #include "tcp.h"
  39
  40 void 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);
  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);
  80         default:
  81                 break;
  82         }
  83 out:
  84         read_unlock_bh(&sk->sk_callback_lock);
  85         state_change(sk);
  86 }
  87
  88 int 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
 148 out:
 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  */
 164 void 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 (cp->cp_conn->c_destroy_in_prog)
 174                         rds_tcp_set_linger(sock);
 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 }