net/caif/chnl_net.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (C) ST-Ericsson AB 2010
   4  * Authors:     Sjur Brendeland
   5  *              Daniel Martensson
   6  */
   7
   8 #define pr_fmt(fmt) KBUILD_MODNAME ":%s(): " fmt, __func__
   9
  10 #include <linux/fs.h>
  11 #include <linux/init.h>
  12 #include <linux/module.h>
  13 #include <linux/netdevice.h>
  14 #include <linux/if_ether.h>
  15 #include <linux/ip.h>
  16 #include <linux/sched.h>
  17 #include <linux/sockios.h>
  18 #include <linux/caif/if_caif.h>
  19 #include <net/rtnetlink.h>
  20 #include <net/caif/caif_layer.h>
  21 #include <net/caif/cfpkt.h>
  22 #include <net/caif/caif_dev.h>
  23
  24 /* GPRS PDP connection has MTU to 1500 */
  25 #define GPRS_PDP_MTU 1500
  26 /* 5 sec. connect timeout */
  27 #define CONNECT_TIMEOUT (5 * HZ)
  28 #define CAIF_NET_DEFAULT_QUEUE_LEN 500
  29 #define UNDEF_CONNID 0xffffffff
  30
  31 /*This list is protected by the rtnl lock. */
  32 static LIST_HEAD(chnl_net_list);
  33
  34 MODULE_DESCRIPTION("ST-Ericsson CAIF modem protocol GPRS network device");
  35 MODULE_LICENSE("GPL");
  36 MODULE_ALIAS_RTNL_LINK("caif");
  37
  38 enum caif_states {
  39         CAIF_CONNECTED          = 1,
  40         CAIF_CONNECTING,
  41         CAIF_DISCONNECTED,
  42         CAIF_SHUTDOWN
  43 };
  44
  45 struct chnl_net {
  46         struct cflayer chnl;
  47         struct caif_connect_request conn_req;
  48         struct list_head list_field;
  49         struct net_device *netdev;
  50         wait_queue_head_t netmgmt_wq;
  51         /* Flow status to remember and control the transmission. */
  52         bool flowenabled;
  53         enum caif_states state;
  54 };
  55
  56 static int chnl_recv_cb(struct cflayer *layr, struct cfpkt *pkt)
  57 {
  58         struct sk_buff *skb;
  59         struct chnl_net *priv;
  60         int pktlen;
  61         const u8 *ip_version;
  62         u8 buf;
  63
  64         priv = container_of(layr, struct chnl_net, chnl);
  65
  66         skb = (struct sk_buff *) cfpkt_tonative(pkt);
  67
  68         /* Get length of CAIF packet. */
  69         pktlen = skb->len;
  70
  71         /* Pass some minimum information and
  72          * send the packet to the net stack.
  73          */
  74         skb->dev = priv->netdev;
  75
  76         /* check the version of IP */
  77         ip_version = skb_header_pointer(skb, 0, 1, &buf);
  78         if (!ip_version) {
  79                 kfree_skb(skb);
  80                 return -EINVAL;
  81         }
  82
  83         switch (*ip_version >> 4) {
  84         case 4:
  85                 skb->protocol = htons(ETH_P_IP);
  86                 break;
  87         case 6:
  88                 skb->protocol = htons(ETH_P_IPV6);
  89                 break;
  90         default:
  91                 kfree_skb(skb);
  92                 priv->netdev->stats.rx_errors++;
  93                 return -EINVAL;
  94         }
  95
  96         /* If we change the header in loop mode, the checksum is corrupted. */
  97         if (priv->conn_req.protocol == CAIFPROTO_DATAGRAM_LOOP)
  98                 skb->ip_summed = CHECKSUM_UNNECESSARY;
  99         else
 100                 skb->ip_summed = CHECKSUM_NONE;
 101
 102         netif_rx(skb);
 103
 104         /* Update statistics. */
 105         priv->netdev->stats.rx_packets++;
 106         priv->netdev->stats.rx_bytes += pktlen;
 107
 108         return 0;
 109 }
 110
 111 static int delete_device(struct chnl_net *dev)
 112 {
 113         ASSERT_RTNL();
 114         if (dev->netdev)
 115                 unregister_netdevice(dev->netdev);
 116         return 0;
 117 }
 118
 119 static void close_work(struct work_struct *work)
 120 {
 121         struct chnl_net *dev = NULL;
 122         struct list_head *list_node;
 123         struct list_head *_tmp;
 124
 125         rtnl_lock();
 126         list_for_each_safe(list_node, _tmp, &chnl_net_list) {
 127                 dev = list_entry(list_node, struct chnl_net, list_field);
 128                 if (dev->state == CAIF_SHUTDOWN)
 129                         dev_close(dev->netdev);
 130         }
 131         rtnl_unlock();
 132 }
 133 static DECLARE_WORK(close_worker, close_work);
 134
 135 static void chnl_hold(struct cflayer *lyr)
 136 {
 137         struct chnl_net *priv = container_of(lyr, struct chnl_net, chnl);
 138         dev_hold(priv->netdev);
 139 }
 140
 141 static void chnl_put(struct cflayer *lyr)
 142 {
 143         struct chnl_net *priv = container_of(lyr, struct chnl_net, chnl);
 144         dev_put(priv->netdev);
 145 }
 146
 147 static void chnl_flowctrl_cb(struct cflayer *layr, enum caif_ctrlcmd flow,
 148                              int phyid)
 149 {
 150         struct chnl_net *priv = container_of(layr, struct chnl_net, chnl);
 151         pr_debug("NET flowctrl func called flow: %s\n",
 152                 flow == CAIF_CTRLCMD_FLOW_ON_IND ? "ON" :
 153                 flow == CAIF_CTRLCMD_INIT_RSP ? "INIT" :
 154                 flow == CAIF_CTRLCMD_FLOW_OFF_IND ? "OFF" :
 155                 flow == CAIF_CTRLCMD_DEINIT_RSP ? "CLOSE/DEINIT" :
 156                 flow == CAIF_CTRLCMD_INIT_FAIL_RSP ? "OPEN_FAIL" :
 157                 flow == CAIF_CTRLCMD_REMOTE_SHUTDOWN_IND ?
 158                  "REMOTE_SHUTDOWN" : "UNKNOWN CTRL COMMAND");
 159
 160
 161
 162         switch (flow) {
 163         case CAIF_CTRLCMD_FLOW_OFF_IND:
 164                 priv->flowenabled = false;
 165                 netif_stop_queue(priv->netdev);
 166                 break;
 167         case CAIF_CTRLCMD_DEINIT_RSP:
 168                 priv->state = CAIF_DISCONNECTED;
 169                 break;
 170         case CAIF_CTRLCMD_INIT_FAIL_RSP:
 171                 priv->state = CAIF_DISCONNECTED;
 172                 wake_up_interruptible(&priv->netmgmt_wq);
 173                 break;
 174         case CAIF_CTRLCMD_REMOTE_SHUTDOWN_IND:
 175                 priv->state = CAIF_SHUTDOWN;
 176                 netif_tx_disable(priv->netdev);
 177                 schedule_work(&close_worker);
 178                 break;
 179         case CAIF_CTRLCMD_FLOW_ON_IND:
 180                 priv->flowenabled = true;
 181                 netif_wake_queue(priv->netdev);
 182                 break;
 183         case CAIF_CTRLCMD_INIT_RSP:
 184                 caif_client_register_refcnt(&priv->chnl, chnl_hold, chnl_put);
 185                 priv->state = CAIF_CONNECTED;
 186                 priv->flowenabled = true;
 187                 netif_wake_queue(priv->netdev);
 188                 wake_up_interruptible(&priv->netmgmt_wq);
 189                 break;
 190         default:
 191                 break;
 192         }
 193 }
 194
 195 static netdev_tx_t chnl_net_start_xmit(struct sk_buff *skb,
 196                                        struct net_device *dev)
 197 {
 198         struct chnl_net *priv;
 199         struct cfpkt *pkt = NULL;
 200         int len;
 201         int result = -1;
 202         /* Get our private data. */
 203         priv = netdev_priv(dev);
 204
 205         if (skb->len > priv->netdev->mtu) {
 206                 pr_warn("Size of skb exceeded MTU\n");
 207                 kfree_skb(skb);
 208                 dev->stats.tx_errors++;
 209                 return NETDEV_TX_OK;
 210         }
 211
 212         if (!priv->flowenabled) {
 213                 pr_debug("dropping packets flow off\n");
 214                 kfree_skb(skb);
 215                 dev->stats.tx_dropped++;
 216                 return NETDEV_TX_OK;
 217         }
 218
 219         if (priv->conn_req.protocol == CAIFPROTO_DATAGRAM_LOOP)
 220                 swap(ip_hdr(skb)->saddr, ip_hdr(skb)->daddr);
 221
 222         /* Store original SKB length. */
 223         len = skb->len;
 224
 225         pkt = cfpkt_fromnative(CAIF_DIR_OUT, (void *) skb);
 226
 227         /* Send the packet down the stack. */
 228         result = priv->chnl.dn->transmit(priv->chnl.dn, pkt);
 229         if (result) {
 230                 dev->stats.tx_dropped++;
 231                 return NETDEV_TX_OK;
 232         }
 233
 234         /* Update statistics. */
 235         dev->stats.tx_packets++;
 236         dev->stats.tx_bytes += len;
 237
 238         return NETDEV_TX_OK;
 239 }
 240
 241 static int chnl_net_open(struct net_device *dev)
 242 {
 243         struct chnl_net *priv = NULL;
 244         int result = -1;
 245         int llifindex, headroom, tailroom, mtu;
 246         struct net_device *lldev;
 247         ASSERT_RTNL();
 248         priv = netdev_priv(dev);
 249         if (!priv) {
 250                 pr_debug("chnl_net_open: no priv\n");
 251                 return -ENODEV;
 252         }
 253
 254         if (priv->state != CAIF_CONNECTING) {
 255                 priv->state = CAIF_CONNECTING;
 256                 result = caif_connect_client(dev_net(dev), &priv->conn_req,
 257                                                 &priv->chnl, &llifindex,
 258                                                 &headroom, &tailroom);
 259                 if (result != 0) {
 260                                 pr_debug("err: "
 261                                          "Unable to register and open device,"
 262                                          " Err:%d\n",
 263                                          result);
 264                                 goto error;
 265                 }
 266
 267                 lldev = __dev_get_by_index(dev_net(dev), llifindex);
 268
 269                 if (lldev == NULL) {
 270                         pr_debug("no interface?\n");
 271                         result = -ENODEV;
 272                         goto error;
 273                 }
 274
 275                 dev->needed_tailroom = tailroom + lldev->needed_tailroom;
 276                 dev->hard_header_len = headroom + lldev->hard_header_len +
 277                         lldev->needed_tailroom;
 278
 279                 /*
 280                  * MTU, head-room etc is not know before we have a
 281                  * CAIF link layer device available. MTU calculation may
 282                  * override initial RTNL configuration.
 283                  * MTU is minimum of current mtu, link layer mtu pluss
 284                  * CAIF head and tail, and PDP GPRS contexts max MTU.
 285                  */
 286                 mtu = min_t(int, dev->mtu, lldev->mtu - (headroom + tailroom));
 287                 mtu = min_t(int, GPRS_PDP_MTU, mtu);
 288                 dev_set_mtu(dev, mtu);
 289
 290                 if (mtu < 100) {
 291                         pr_warn("CAIF Interface MTU too small (%d)\n", mtu);
 292                         result = -ENODEV;
 293                         goto error;
 294                 }
 295         }
 296
 297         rtnl_unlock();  /* Release RTNL lock during connect wait */
 298
 299         result = wait_event_interruptible_timeout(priv->netmgmt_wq,
 300                                                 priv->state != CAIF_CONNECTING,
 301                                                 CONNECT_TIMEOUT);
 302
 303         rtnl_lock();
 304
 305         if (result == -ERESTARTSYS) {
 306                 pr_debug("wait_event_interruptible woken by a signal\n");
 307                 result = -ERESTARTSYS;
 308                 goto error;
 309         }
 310
 311         if (result == 0) {
 312                 pr_debug("connect timeout\n");
 313                 result = -ETIMEDOUT;
 314                 goto error;
 315         }
 316
 317         if (priv->state != CAIF_CONNECTED) {
 318                 pr_debug("connect failed\n");
 319                 result = -ECONNREFUSED;
 320                 goto error;
 321         }
 322         pr_debug("CAIF Netdevice connected\n");
 323         return 0;
 324
 325 error:
 326         caif_disconnect_client(dev_net(dev), &priv->chnl);
 327         priv->state = CAIF_DISCONNECTED;
 328         pr_debug("state disconnected\n");
 329         return result;
 330
 331 }
 332
 333 static int chnl_net_stop(struct net_device *dev)
 334 {
 335         struct chnl_net *priv;
 336
 337         ASSERT_RTNL();
 338         priv = netdev_priv(dev);
 339         priv->state = CAIF_DISCONNECTED;
 340         caif_disconnect_client(dev_net(dev), &priv->chnl);
 341         return 0;
 342 }
 343
 344 static int chnl_net_init(struct net_device *dev)
 345 {
 346         struct chnl_net *priv;
 347         ASSERT_RTNL();
 348         priv = netdev_priv(dev);
 349         INIT_LIST_HEAD(&priv->list_field);
 350         return 0;
 351 }
 352
 353 static void chnl_net_uninit(struct net_device *dev)
 354 {
 355         struct chnl_net *priv;
 356         ASSERT_RTNL();
 357         priv = netdev_priv(dev);
 358         list_del_init(&priv->list_field);
 359 }
 360
 361 static const struct net_device_ops netdev_ops = {
 362         .ndo_open = chnl_net_open,
 363         .ndo_stop = chnl_net_stop,
 364         .ndo_init = chnl_net_init,
 365         .ndo_uninit = chnl_net_uninit,
 366         .ndo_start_xmit = chnl_net_start_xmit,
 367 };
 368
 369 static void chnl_net_destructor(struct net_device *dev)
 370 {
 371         struct chnl_net *priv = netdev_priv(dev);
 372         caif_free_client(&priv->chnl);
 373 }
 374
 375 static void ipcaif_net_setup(struct net_device *dev)
 376 {
 377         struct chnl_net *priv;
 378         dev->netdev_ops = &netdev_ops;
 379         dev->needs_free_netdev = true;
 380         dev->priv_destructor = chnl_net_destructor;
 381         dev->flags |= IFF_NOARP;
 382         dev->flags |= IFF_POINTOPOINT;
 383         dev->mtu = GPRS_PDP_MTU;
 384         dev->tx_queue_len = CAIF_NET_DEFAULT_QUEUE_LEN;
 385
 386         priv = netdev_priv(dev);
 387         priv->chnl.receive = chnl_recv_cb;
 388         priv->chnl.ctrlcmd = chnl_flowctrl_cb;
 389         priv->netdev = dev;
 390         priv->conn_req.protocol = CAIFPROTO_DATAGRAM;
 391         priv->conn_req.link_selector = CAIF_LINK_HIGH_BANDW;
 392         priv->conn_req.priority = CAIF_PRIO_LOW;
 393         /* Insert illegal value */
 394         priv->conn_req.sockaddr.u.dgm.connection_id = UNDEF_CONNID;
 395         priv->flowenabled = false;
 396
 397         init_waitqueue_head(&priv->netmgmt_wq);
 398 }
 399
 400
 401 static int ipcaif_fill_info(struct sk_buff *skb, const struct net_device *dev)
 402 {
 403         struct chnl_net *priv;
 404         u8 loop;
 405         priv = netdev_priv(dev);
 406         if (nla_put_u32(skb, IFLA_CAIF_IPV4_CONNID,
 407                         priv->conn_req.sockaddr.u.dgm.connection_id) ||
 408             nla_put_u32(skb, IFLA_CAIF_IPV6_CONNID,
 409                         priv->conn_req.sockaddr.u.dgm.connection_id))
 410                 goto nla_put_failure;
 411         loop = priv->conn_req.protocol == CAIFPROTO_DATAGRAM_LOOP;
 412         if (nla_put_u8(skb, IFLA_CAIF_LOOPBACK, loop))
 413                 goto nla_put_failure;
 414         return 0;
 415 nla_put_failure:
 416         return -EMSGSIZE;
 417
 418 }
 419
 420 static void caif_netlink_parms(struct nlattr *data[],
 421                                struct caif_connect_request *conn_req)
 422 {
 423         if (!data) {
 424                 pr_warn("no params data found\n");
 425                 return;
 426         }
 427         if (data[IFLA_CAIF_IPV4_CONNID])
 428                 conn_req->sockaddr.u.dgm.connection_id =
 429                         nla_get_u32(data[IFLA_CAIF_IPV4_CONNID]);
 430         if (data[IFLA_CAIF_IPV6_CONNID])
 431                 conn_req->sockaddr.u.dgm.connection_id =
 432                         nla_get_u32(data[IFLA_CAIF_IPV6_CONNID]);
 433         if (data[IFLA_CAIF_LOOPBACK]) {
 434                 if (nla_get_u8(data[IFLA_CAIF_LOOPBACK]))
 435                         conn_req->protocol = CAIFPROTO_DATAGRAM_LOOP;
 436                 else
 437                         conn_req->protocol = CAIFPROTO_DATAGRAM;
 438         }
 439 }
 440
 441 static int ipcaif_newlink(struct net *src_net, struct net_device *dev,
 442                           struct nlattr *tb[], struct nlattr *data[],
 443                           struct netlink_ext_ack *extack)
 444 {
 445         int ret;
 446         struct chnl_net *caifdev;
 447         ASSERT_RTNL();
 448         caifdev = netdev_priv(dev);
 449         caif_netlink_parms(data, &caifdev->conn_req);
 450
 451         ret = register_netdevice(dev);
 452         if (ret)
 453                 pr_warn("device rtml registration failed\n");
 454         else
 455                 list_add(&caifdev->list_field, &chnl_net_list);
 456
 457         /* Use ifindex as connection id, and use loopback channel default. */
 458         if (caifdev->conn_req.sockaddr.u.dgm.connection_id == UNDEF_CONNID) {
 459                 caifdev->conn_req.sockaddr.u.dgm.connection_id = dev->ifindex;
 460                 caifdev->conn_req.protocol = CAIFPROTO_DATAGRAM_LOOP;
 461         }
 462         return ret;
 463 }
 464
 465 static int ipcaif_changelink(struct net_device *dev, struct nlattr *tb[],
 466                              struct nlattr *data[],
 467                              struct netlink_ext_ack *extack)
 468 {
 469         struct chnl_net *caifdev;
 470         ASSERT_RTNL();
 471         caifdev = netdev_priv(dev);
 472         caif_netlink_parms(data, &caifdev->conn_req);
 473         netdev_state_change(dev);
 474         return 0;
 475 }
 476
 477 static size_t ipcaif_get_size(const struct net_device *dev)
 478 {
 479         return
 480                 /* IFLA_CAIF_IPV4_CONNID */
 481                 nla_total_size(4) +
 482                 /* IFLA_CAIF_IPV6_CONNID */
 483                 nla_total_size(4) +
 484                 /* IFLA_CAIF_LOOPBACK */
 485                 nla_total_size(2) +
 486                 0;
 487 }
 488
 489 static const struct nla_policy ipcaif_policy[IFLA_CAIF_MAX + 1] = {
 490         [IFLA_CAIF_IPV4_CONNID]       = { .type = NLA_U32 },
 491         [IFLA_CAIF_IPV6_CONNID]       = { .type = NLA_U32 },
 492         [IFLA_CAIF_LOOPBACK]          = { .type = NLA_U8 }
 493 };
 494
 495
 496 static struct rtnl_link_ops ipcaif_link_ops __read_mostly = {
 497         .kind           = "caif",
 498         .priv_size      = sizeof(struct chnl_net),
 499         .setup          = ipcaif_net_setup,
 500         .maxtype        = IFLA_CAIF_MAX,
 501         .policy         = ipcaif_policy,
 502         .newlink        = ipcaif_newlink,
 503         .changelink     = ipcaif_changelink,
 504         .get_size       = ipcaif_get_size,
 505         .fill_info      = ipcaif_fill_info,
 506
 507 };
 508
 509 static int __init chnl_init_module(void)
 510 {
 511         return rtnl_link_register(&ipcaif_link_ops);
 512 }
 513
 514 static void __exit chnl_exit_module(void)
 515 {
 516         struct chnl_net *dev = NULL;
 517         struct list_head *list_node;
 518         struct list_head *_tmp;
 519         rtnl_link_unregister(&ipcaif_link_ops);
 520         rtnl_lock();
 521         list_for_each_safe(list_node, _tmp, &chnl_net_list) {
 522                 dev = list_entry(list_node, struct chnl_net, list_field);
 523                 list_del_init(list_node);
 524                 delete_device(dev);
 525         }
 526         rtnl_unlock();
 527 }
 528
 529 module_init(chnl_init_module);
 530 module_exit(chnl_exit_module);