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
  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 /* rds_tcp_accept_one_path(): if accepting on cp_index > 0, make sure the
  74  * client's ipaddr < server's ipaddr. Otherwise, close the accepted
  75  * socket and force a reconneect from smaller -> larger ip addr. The reason
  76  * we special case cp_index 0 is to allow the rds probe ping itself to itself
  77  * get through efficiently.
  78  * Since reconnects are only initiated from the node with the numerically
  79  * smaller ip address, we recycle conns in RDS_CONN_ERROR on the passive side
  80  * by moving them to CONNECTING in this function.
  81  */
  82 static
  83 struct rds_tcp_connection *rds_tcp_accept_one_path(struct rds_connection *conn)
  84 {
  85         int i;
  86         int npaths = max_t(int, 1, conn->c_npaths);
  87
  88         /* for mprds, all paths MUST be initiated by the peer
  89          * with the smaller address.
  90          */
  91         if (rds_addr_cmp(&conn->c_faddr, &conn->c_laddr) >= 0) {
  92                 /* Make sure we initiate at least one path if this
  93                  * has not already been done; rds_start_mprds() will
  94                  * take care of additional paths, if necessary.
  95                  */
  96                 if (npaths == 1)
  97                         rds_conn_path_connect_if_down(&conn->c_path[0]);
  98                 return NULL;
  99         }
 100
 101         for (i = 0; i < npaths; i++) {
 102                 struct rds_conn_path *cp = &conn->c_path[i];
 103
 104                 if (rds_conn_path_transition(cp, RDS_CONN_DOWN,
 105                                              RDS_CONN_CONNECTING) ||
 106                     rds_conn_path_transition(cp, RDS_CONN_ERROR,
 107                                              RDS_CONN_CONNECTING)) {
 108                         return cp->cp_transport_data;
 109                 }
 110         }
 111         return NULL;
 112 }
 113
 114 void rds_tcp_set_linger(struct socket *sock)
 115 {
 116         struct linger no_linger = {
 117                 .l_onoff = 1,
 118                 .l_linger = 0,
 119         };
 120
 121         kernel_setsockopt(sock, SOL_SOCKET, SO_LINGER,
 122                           (char *)&no_linger, sizeof(no_linger));
 123 }
 124
 125 int rds_tcp_accept_one(struct socket *sock)
 126 {
 127         struct socket *new_sock = NULL;
 128         struct rds_connection *conn;
 129         int ret;
 130         struct inet_sock *inet;
 131         struct rds_tcp_connection *rs_tcp = NULL;
 132         int conn_state;
 133         struct rds_conn_path *cp;
 134         struct in6_addr *my_addr, *peer_addr;
 135 #if !IS_ENABLED(CONFIG_IPV6)
 136         struct in6_addr saddr, daddr;
 137 #endif
 138         int dev_if = 0;
 139
 140         if (!sock) /* module unload or netns delete in progress */
 141                 return -ENETUNREACH;
 142
 143         ret = sock_create_lite(sock->sk->sk_family,
 144                                sock->sk->sk_type, sock->sk->sk_protocol,
 145                                &new_sock);
 146         if (ret)
 147                 goto out;
 148
 149         ret = sock->ops->accept(sock, new_sock, O_NONBLOCK, true);
 150         if (ret < 0)
 151                 goto out;
 152
 153         /* sock_create_lite() does not get a hold on the owner module so we
 154          * need to do it here.  Note that sock_release() uses sock->ops to
 155          * determine if it needs to decrement the reference count.  So set
 156          * sock->ops after calling accept() in case that fails.  And there's
 157          * no need to do try_module_get() as the listener should have a hold
 158          * already.
 159          */
 160         new_sock->ops = sock->ops;
 161         __module_get(new_sock->ops->owner);
 162
 163         ret = rds_tcp_keepalive(new_sock);
 164         if (ret < 0)
 165                 goto out;
 166
 167         rds_tcp_tune(new_sock);
 168
 169         inet = inet_sk(new_sock->sk);
 170
 171 #if IS_ENABLED(CONFIG_IPV6)
 172         my_addr = &new_sock->sk->sk_v6_rcv_saddr;
 173         peer_addr = &new_sock->sk->sk_v6_daddr;
 174 #else
 175         ipv6_addr_set_v4mapped(inet->inet_saddr, &saddr);
 176         ipv6_addr_set_v4mapped(inet->inet_daddr, &daddr);
 177         my_addr = &saddr;
 178         peer_addr = &daddr;
 179 #endif
 180         rdsdebug("accepted family %d tcp %pI6c:%u -> %pI6c:%u\n",
 181                  sock->sk->sk_family,
 182                  my_addr, ntohs(inet->inet_sport),
 183                  peer_addr, ntohs(inet->inet_dport));
 184
 185 #if IS_ENABLED(CONFIG_IPV6)
 186         /* sk_bound_dev_if is not set if the peer address is not link local
 187          * address.  In this case, it happens that mcast_oif is set.  So
 188          * just use it.
 189          */
 190         if ((ipv6_addr_type(my_addr) & IPV6_ADDR_LINKLOCAL) &&
 191             !(ipv6_addr_type(peer_addr) & IPV6_ADDR_LINKLOCAL)) {
 192                 struct ipv6_pinfo *inet6;
 193
 194                 inet6 = inet6_sk(new_sock->sk);
 195                 dev_if = inet6->mcast_oif;
 196         } else {
 197                 dev_if = new_sock->sk->sk_bound_dev_if;
 198         }
 199 #endif
 200
 201         conn = rds_conn_create(sock_net(sock->sk),
 202                                my_addr, peer_addr,
 203                                &rds_tcp_transport, 0, GFP_KERNEL, dev_if);
 204
 205         if (IS_ERR(conn)) {
 206                 ret = PTR_ERR(conn);
 207                 goto out;
 208         }
 209         /* An incoming SYN request came in, and TCP just accepted it.
 210          *
 211          * If the client reboots, this conn will need to be cleaned up.
 212          * rds_tcp_state_change() will do that cleanup
 213          */
 214         rs_tcp = rds_tcp_accept_one_path(conn);
 215         if (!rs_tcp)
 216                 goto rst_nsk;
 217         mutex_lock(&rs_tcp->t_conn_path_lock);
 218         cp = rs_tcp->t_cpath;
 219         conn_state = rds_conn_path_state(cp);
 220         WARN_ON(conn_state == RDS_CONN_UP);
 221         if (conn_state != RDS_CONN_CONNECTING && conn_state != RDS_CONN_ERROR)
 222                 goto rst_nsk;
 223         if (rs_tcp->t_sock) {
 224                 /* Duelling SYN has been handled in rds_tcp_accept_one() */
 225                 rds_tcp_reset_callbacks(new_sock, cp);
 226                 /* rds_connect_path_complete() marks RDS_CONN_UP */
 227                 rds_connect_path_complete(cp, RDS_CONN_RESETTING);
 228         } else {
 229                 rds_tcp_set_callbacks(new_sock, cp);
 230                 rds_connect_path_complete(cp, RDS_CONN_CONNECTING);
 231         }
 232         new_sock = NULL;
 233         ret = 0;
 234         if (conn->c_npaths == 0)
 235                 rds_send_ping(cp->cp_conn, cp->cp_index);
 236         goto out;
 237 rst_nsk:
 238         /* reset the newly returned accept sock and bail.
 239          * It is safe to set linger on new_sock because the RDS connection
 240          * has not been brought up on new_sock, so no RDS-level data could
 241          * be pending on it. By setting linger, we achieve the side-effect
 242          * of avoiding TIME_WAIT state on new_sock.
 243          */
 244         rds_tcp_set_linger(new_sock);
 245         kernel_sock_shutdown(new_sock, SHUT_RDWR);
 246         ret = 0;
 247 out:
 248         if (rs_tcp)
 249                 mutex_unlock(&rs_tcp->t_conn_path_lock);
 250         if (new_sock)
 251                 sock_release(new_sock);
 252         return ret;
 253 }
 254
 255 void rds_tcp_listen_data_ready(struct sock *sk)
 256 {
 257         void (*ready)(struct sock *sk);
 258
 259         rdsdebug("listen data ready sk %p\n", sk);
 260
 261         read_lock_bh(&sk->sk_callback_lock);
 262         ready = sk->sk_user_data;
 263         if (!ready) { /* check for teardown race */
 264                 ready = sk->sk_data_ready;
 265                 goto out;
 266         }
 267
 268         /*
 269          * ->sk_data_ready is also called for a newly established child socket
 270          * before it has been accepted and the accepter has set up their
 271          * data_ready.. we only want to queue listen work for our listening
 272          * socket
 273          *
 274          * (*ready)() may be null if we are racing with netns delete, and
 275          * the listen socket is being torn down.
 276          */
 277         if (sk->sk_state == TCP_LISTEN)
 278                 rds_tcp_accept_work(sk);
 279         else
 280                 ready = rds_tcp_listen_sock_def_readable(sock_net(sk));
 281
 282 out:
 283         read_unlock_bh(&sk->sk_callback_lock);
 284         if (ready)
 285                 ready(sk);
 286 }
 287
 288 struct socket *rds_tcp_listen_init(struct net *net, bool isv6)
 289 {
 290         struct socket *sock = NULL;
 291         struct sockaddr_storage ss;
 292         struct sockaddr_in6 *sin6;
 293         struct sockaddr_in *sin;
 294         int addr_len;
 295         int ret;
 296
 297         ret = sock_create_kern(net, isv6 ? PF_INET6 : PF_INET, SOCK_STREAM,
 298                                IPPROTO_TCP, &sock);
 299         if (ret < 0) {
 300                 rdsdebug("could not create %s listener socket: %d\n",
 301                          isv6 ? "IPv6" : "IPv4", ret);
 302                 goto out;
 303         }
 304
 305         sock->sk->sk_reuse = SK_CAN_REUSE;
 306         rds_tcp_nonagle(sock);
 307
 308         write_lock_bh(&sock->sk->sk_callback_lock);
 309         sock->sk->sk_user_data = sock->sk->sk_data_ready;
 310         sock->sk->sk_data_ready = rds_tcp_listen_data_ready;
 311         write_unlock_bh(&sock->sk->sk_callback_lock);
 312
 313         if (isv6) {
 314                 sin6 = (struct sockaddr_in6 *)&ss;
 315                 sin6->sin6_family = PF_INET6;
 316                 sin6->sin6_addr = in6addr_any;
 317                 sin6->sin6_port = (__force u16)htons(RDS_TCP_PORT);
 318                 sin6->sin6_scope_id = 0;
 319                 sin6->sin6_flowinfo = 0;
 320                 addr_len = sizeof(*sin6);
 321         } else {
 322                 sin = (struct sockaddr_in *)&ss;
 323                 sin->sin_family = PF_INET;
 324                 sin->sin_addr.s_addr = INADDR_ANY;
 325                 sin->sin_port = (__force u16)htons(RDS_TCP_PORT);
 326                 addr_len = sizeof(*sin);
 327         }
 328
 329         ret = sock->ops->bind(sock, (struct sockaddr *)&ss, addr_len);
 330         if (ret < 0) {
 331                 rdsdebug("could not bind %s listener socket: %d\n",
 332                          isv6 ? "IPv6" : "IPv4", ret);
 333                 goto out;
 334         }
 335
 336         ret = sock->ops->listen(sock, 64);
 337         if (ret < 0)
 338                 goto out;
 339
 340         return sock;
 341 out:
 342         if (sock)
 343                 sock_release(sock);
 344         return NULL;
 345 }
 346
 347 void rds_tcp_listen_stop(struct socket *sock, struct work_struct *acceptor)
 348 {
 349         struct sock *sk;
 350
 351         if (!sock)
 352                 return;
 353
 354         sk = sock->sk;
 355
 356         /* serialize with and prevent further callbacks */
 357         lock_sock(sk);
 358         write_lock_bh(&sk->sk_callback_lock);
 359         if (sk->sk_user_data) {
 360                 sk->sk_data_ready = sk->sk_user_data;
 361                 sk->sk_user_data = NULL;
 362         }
 363         write_unlock_bh(&sk->sk_callback_lock);
 364         release_sock(sk);
 365
 366         /* wait for accepts to stop and close the socket */
 367         flush_workqueue(rds_wq);
 368         flush_work(acceptor);
 369         sock_release(sock);
 370 }