net/rds/tcp_listen.c

   1 /*
   2  * Copyright (c) 2006, 2018 Oracle and/or its affiliates. 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 #include <trace/events/sock.h>
  38
  39 #include "rds.h"
  40 #include "tcp.h"
  41
  42 void rds_tcp_keepalive(struct socket *sock)
  43 {
  44         /* values below based on xs_udp_default_timeout */
  45         int keepidle = 5; /* send a probe 'keepidle' secs after last data */
  46         int keepcnt = 5; /* number of unack'ed probes before declaring dead */
  47
  48         sock_set_keepalive(sock->sk);
  49         tcp_sock_set_keepcnt(sock->sk, keepcnt);
  50         tcp_sock_set_keepidle(sock->sk, keepidle);
  51         /* KEEPINTVL is the interval between successive probes. We follow
  52          * the model in xs_tcp_finish_connecting() and re-use keepidle.
  53          */
  54         tcp_sock_set_keepintvl(sock->sk, keepidle);
  55 }
  56
  57 /* rds_tcp_accept_one_path(): if accepting on cp_index > 0, make sure the
  58  * client's ipaddr < server's ipaddr. Otherwise, close the accepted
  59  * socket and force a reconneect from smaller -> larger ip addr. The reason
  60  * we special case cp_index 0 is to allow the rds probe ping itself to itself
  61  * get through efficiently.
  62  * Since reconnects are only initiated from the node with the numerically
  63  * smaller ip address, we recycle conns in RDS_CONN_ERROR on the passive side
  64  * by moving them to CONNECTING in this function.
  65  */
  66 static
  67 struct rds_tcp_connection *rds_tcp_accept_one_path(struct rds_connection *conn)
  68 {
  69         int i;
  70         int npaths = max_t(int, 1, conn->c_npaths);
  71
  72         /* for mprds, all paths MUST be initiated by the peer
  73          * with the smaller address.
  74          */
  75         if (rds_addr_cmp(&conn->c_faddr, &conn->c_laddr) >= 0) {
  76                 /* Make sure we initiate at least one path if this
  77                  * has not already been done; rds_start_mprds() will
  78                  * take care of additional paths, if necessary.
  79                  */
  80                 if (npaths == 1)
  81                         rds_conn_path_connect_if_down(&conn->c_path[0]);
  82                 return NULL;
  83         }
  84
  85         for (i = 0; i < npaths; i++) {
  86                 struct rds_conn_path *cp = &conn->c_path[i];
  87
  88                 if (rds_conn_path_transition(cp, RDS_CONN_DOWN,
  89                                              RDS_CONN_CONNECTING) ||
  90                     rds_conn_path_transition(cp, RDS_CONN_ERROR,
  91                                              RDS_CONN_CONNECTING)) {
  92                         return cp->cp_transport_data;
  93                 }
  94         }
  95         return NULL;
  96 }
  97
  98 int rds_tcp_accept_one(struct socket *sock)
  99 {
 100         struct socket *new_sock = NULL;
 101         struct rds_connection *conn;
 102         int ret;
 103         struct inet_sock *inet;
 104         struct rds_tcp_connection *rs_tcp = NULL;
 105         int conn_state;
 106         struct rds_conn_path *cp;
 107         struct in6_addr *my_addr, *peer_addr;
 108         struct proto_accept_arg arg = {
 109                 .flags = O_NONBLOCK,
 110                 .kern = true,
 111         };
 112 #if !IS_ENABLED(CONFIG_IPV6)
 113         struct in6_addr saddr, daddr;
 114 #endif
 115         int dev_if = 0;
 116
 117         if (!sock) /* module unload or netns delete in progress */
 118                 return -ENETUNREACH;
 119
 120         ret = sock_create_lite(sock->sk->sk_family,
 121                                sock->sk->sk_type, sock->sk->sk_protocol,
 122                                &new_sock);
 123         if (ret)
 124                 goto out;
 125
 126         ret = sock->ops->accept(sock, new_sock, &arg);
 127         if (ret < 0)
 128                 goto out;
 129
 130         /* sock_create_lite() does not get a hold on the owner module so we
 131          * need to do it here.  Note that sock_release() uses sock->ops to
 132          * determine if it needs to decrement the reference count.  So set
 133          * sock->ops after calling accept() in case that fails.  And there's
 134          * no need to do try_module_get() as the listener should have a hold
 135          * already.
 136          */
 137         new_sock->ops = sock->ops;
 138         __module_get(new_sock->ops->owner);
 139
 140         rds_tcp_keepalive(new_sock);
 141         if (!rds_tcp_tune(new_sock)) {
 142                 ret = -EINVAL;
 143                 goto out;
 144         }
 145
 146         inet = inet_sk(new_sock->sk);
 147
 148 #if IS_ENABLED(CONFIG_IPV6)
 149         my_addr = &new_sock->sk->sk_v6_rcv_saddr;
 150         peer_addr = &new_sock->sk->sk_v6_daddr;
 151 #else
 152         ipv6_addr_set_v4mapped(inet->inet_saddr, &saddr);
 153         ipv6_addr_set_v4mapped(inet->inet_daddr, &daddr);
 154         my_addr = &saddr;
 155         peer_addr = &daddr;
 156 #endif
 157         rdsdebug("accepted family %d tcp %pI6c:%u -> %pI6c:%u\n",
 158                  sock->sk->sk_family,
 159                  my_addr, ntohs(inet->inet_sport),
 160                  peer_addr, ntohs(inet->inet_dport));
 161
 162 #if IS_ENABLED(CONFIG_IPV6)
 163         /* sk_bound_dev_if is not set if the peer address is not link local
 164          * address.  In this case, it happens that mcast_oif is set.  So
 165          * just use it.
 166          */
 167         if ((ipv6_addr_type(my_addr) & IPV6_ADDR_LINKLOCAL) &&
 168             !(ipv6_addr_type(peer_addr) & IPV6_ADDR_LINKLOCAL)) {
 169                 struct ipv6_pinfo *inet6;
 170
 171                 inet6 = inet6_sk(new_sock->sk);
 172                 dev_if = READ_ONCE(inet6->mcast_oif);
 173         } else {
 174                 dev_if = new_sock->sk->sk_bound_dev_if;
 175         }
 176 #endif
 177
 178         if (!rds_tcp_laddr_check(sock_net(sock->sk), peer_addr, dev_if)) {
 179                 /* local address connection is only allowed via loopback */
 180                 ret = -EOPNOTSUPP;
 181                 goto out;
 182         }
 183
 184         conn = rds_conn_create(sock_net(sock->sk),
 185                                my_addr, peer_addr,
 186                                &rds_tcp_transport, 0, GFP_KERNEL, dev_if);
 187
 188         if (IS_ERR(conn)) {
 189                 ret = PTR_ERR(conn);
 190                 goto out;
 191         }
 192         /* An incoming SYN request came in, and TCP just accepted it.
 193          *
 194          * If the client reboots, this conn will need to be cleaned up.
 195          * rds_tcp_state_change() will do that cleanup
 196          */
 197         rs_tcp = rds_tcp_accept_one_path(conn);
 198         if (!rs_tcp)
 199                 goto rst_nsk;
 200         mutex_lock(&rs_tcp->t_conn_path_lock);
 201         cp = rs_tcp->t_cpath;
 202         conn_state = rds_conn_path_state(cp);
 203         WARN_ON(conn_state == RDS_CONN_UP);
 204         if (conn_state != RDS_CONN_CONNECTING && conn_state != RDS_CONN_ERROR)
 205                 goto rst_nsk;
 206         if (rs_tcp->t_sock) {
 207                 /* Duelling SYN has been handled in rds_tcp_accept_one() */
 208                 rds_tcp_reset_callbacks(new_sock, cp);
 209                 /* rds_connect_path_complete() marks RDS_CONN_UP */
 210                 rds_connect_path_complete(cp, RDS_CONN_RESETTING);
 211         } else {
 212                 rds_tcp_set_callbacks(new_sock, cp);
 213                 rds_connect_path_complete(cp, RDS_CONN_CONNECTING);
 214         }
 215         new_sock = NULL;
 216         ret = 0;
 217         if (conn->c_npaths == 0)
 218                 rds_send_ping(cp->cp_conn, cp->cp_index);
 219         goto out;
 220 rst_nsk:
 221         /* reset the newly returned accept sock and bail.
 222          * It is safe to set linger on new_sock because the RDS connection
 223          * has not been brought up on new_sock, so no RDS-level data could
 224          * be pending on it. By setting linger, we achieve the side-effect
 225          * of avoiding TIME_WAIT state on new_sock.
 226          */
 227         sock_no_linger(new_sock->sk);
 228         kernel_sock_shutdown(new_sock, SHUT_RDWR);
 229         ret = 0;
 230 out:
 231         if (rs_tcp)
 232                 mutex_unlock(&rs_tcp->t_conn_path_lock);
 233         if (new_sock)
 234                 sock_release(new_sock);
 235         return ret;
 236 }
 237
 238 void rds_tcp_listen_data_ready(struct sock *sk)
 239 {
 240         void (*ready)(struct sock *sk);
 241
 242         trace_sk_data_ready(sk);
 243         rdsdebug("listen data ready sk %p\n", sk);
 244
 245         read_lock_bh(&sk->sk_callback_lock);
 246         ready = sk->sk_user_data;
 247         if (!ready) { /* check for teardown race */
 248                 ready = sk->sk_data_ready;
 249                 goto out;
 250         }
 251
 252         /*
 253          * ->sk_data_ready is also called for a newly established child socket
 254          * before it has been accepted and the accepter has set up their
 255          * data_ready.. we only want to queue listen work for our listening
 256          * socket
 257          *
 258          * (*ready)() may be null if we are racing with netns delete, and
 259          * the listen socket is being torn down.
 260          */
 261         if (sk->sk_state == TCP_LISTEN)
 262                 rds_tcp_accept_work(sk);
 263         else
 264                 ready = rds_tcp_listen_sock_def_readable(sock_net(sk));
 265
 266 out:
 267         read_unlock_bh(&sk->sk_callback_lock);
 268         if (ready)
 269                 ready(sk);
 270 }
 271
 272 struct socket *rds_tcp_listen_init(struct net *net, bool isv6)
 273 {
 274         struct socket *sock = NULL;
 275         struct sockaddr_storage ss;
 276         struct sockaddr_in6 *sin6;
 277         struct sockaddr_in *sin;
 278         int addr_len;
 279         int ret;
 280
 281         ret = sock_create_kern(net, isv6 ? PF_INET6 : PF_INET, SOCK_STREAM,
 282                                IPPROTO_TCP, &sock);
 283         if (ret < 0) {
 284                 rdsdebug("could not create %s listener socket: %d\n",
 285                          isv6 ? "IPv6" : "IPv4", ret);
 286                 goto out;
 287         }
 288
 289         sock->sk->sk_reuse = SK_CAN_REUSE;
 290         tcp_sock_set_nodelay(sock->sk);
 291
 292         write_lock_bh(&sock->sk->sk_callback_lock);
 293         sock->sk->sk_user_data = sock->sk->sk_data_ready;
 294         sock->sk->sk_data_ready = rds_tcp_listen_data_ready;
 295         write_unlock_bh(&sock->sk->sk_callback_lock);
 296
 297         if (isv6) {
 298                 sin6 = (struct sockaddr_in6 *)&ss;
 299                 sin6->sin6_family = PF_INET6;
 300                 sin6->sin6_addr = in6addr_any;
 301                 sin6->sin6_port = (__force u16)htons(RDS_TCP_PORT);
 302                 sin6->sin6_scope_id = 0;
 303                 sin6->sin6_flowinfo = 0;
 304                 addr_len = sizeof(*sin6);
 305         } else {
 306                 sin = (struct sockaddr_in *)&ss;
 307                 sin->sin_family = PF_INET;
 308                 sin->sin_addr.s_addr = INADDR_ANY;
 309                 sin->sin_port = (__force u16)htons(RDS_TCP_PORT);
 310                 addr_len = sizeof(*sin);
 311         }
 312
 313         ret = kernel_bind(sock, (struct sockaddr *)&ss, addr_len);
 314         if (ret < 0) {
 315                 rdsdebug("could not bind %s listener socket: %d\n",
 316                          isv6 ? "IPv6" : "IPv4", ret);
 317                 goto out;
 318         }
 319
 320         ret = sock->ops->listen(sock, 64);
 321         if (ret < 0)
 322                 goto out;
 323
 324         return sock;
 325 out:
 326         if (sock)
 327                 sock_release(sock);
 328         return NULL;
 329 }
 330
 331 void rds_tcp_listen_stop(struct socket *sock, struct work_struct *acceptor)
 332 {
 333         struct sock *sk;
 334
 335         if (!sock)
 336                 return;
 337
 338         sk = sock->sk;
 339
 340         /* serialize with and prevent further callbacks */
 341         lock_sock(sk);
 342         write_lock_bh(&sk->sk_callback_lock);
 343         if (sk->sk_user_data) {
 344                 sk->sk_data_ready = sk->sk_user_data;
 345                 sk->sk_user_data = NULL;
 346         }
 347         write_unlock_bh(&sk->sk_callback_lock);
 348         release_sock(sk);
 349
 350         /* wait for accepts to stop and close the socket */
 351         flush_workqueue(rds_wq);
 352         flush_work(acceptor);
 353         sock_release(sock);
 354 }