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_LICENSE("GPL");
  35 MODULE_ALIAS_RTNL_LINK("caif");
  36
  37 enum caif_states {
  38         CAIF_CONNECTED          = 1,
  39         CAIF_CONNECTING,
  40         CAIF_DISCONNECTED,
  41         CAIF_SHUTDOWN
  42 };
  43
  44 struct chnl_net {
  45         struct cflayer chnl;
  46         struct caif_connect_request conn_req;
  47         struct list_head list_field;
  48         struct net_device *netdev;
  49         char name[256];
  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 void robust_list_del(struct list_head *delete_node)
  57 {
  58         struct list_head *list_node;
  59         struct list_head *n;
  60         ASSERT_RTNL();
  61         list_for_each_safe(list_node, n, &chnl_net_list) {
  62                 if (list_node == delete_node) {
  63                         list_del(list_node);
  64                         return;
  65                 }
  66         }
  67         WARN_ON(1);
  68 }
  69
  70 static int chnl_recv_cb(struct cflayer *layr, struct cfpkt *pkt)
  71 {
  72         struct sk_buff *skb;
  73         struct chnl_net *priv;
  74         int pktlen;
  75         const u8 *ip_version;
  76         u8 buf;
  77
  78         priv = container_of(layr, struct chnl_net, chnl);
  79         if (!priv)
  80                 return -EINVAL;
  81
  82         skb = (struct sk_buff *) cfpkt_tonative(pkt);
  83
  84         /* Get length of CAIF packet. */
  85         pktlen = skb->len;
  86
  87         /* Pass some minimum information and
  88          * send the packet to the net stack.
  89          */
  90         skb->dev = priv->netdev;
  91
  92         /* check the version of IP */
  93         ip_version = skb_header_pointer(skb, 0, 1, &buf);
  94         if (!ip_version) {
  95                 kfree_skb(skb);
  96                 return -EINVAL;
  97         }
  98
  99         switch (*ip_version >> 4) {
 100         case 4:
 101                 skb->protocol = htons(ETH_P_IP);
 102                 break;
 103         case 6:
 104                 skb->protocol = htons(ETH_P_IPV6);
 105                 break;
 106         default:
 107                 kfree_skb(skb);
 108                 priv->netdev->stats.rx_errors++;
 109                 return -EINVAL;
 110         }
 111
 112         /* If we change the header in loop mode, the checksum is corrupted. */
 113         if (priv->conn_req.protocol == CAIFPROTO_DATAGRAM_LOOP)
 114                 skb->ip_summed = CHECKSUM_UNNECESSARY;
 115         else
 116                 skb->ip_summed = CHECKSUM_NONE;
 117
 118         if (in_interrupt())
 119                 netif_rx(skb);
 120         else
 121                 netif_rx_ni(skb);
 122
 123         /* Update statistics. */
 124         priv->netdev->stats.rx_packets++;
 125         priv->netdev->stats.rx_bytes += pktlen;
 126
 127         return 0;
 128 }
 129
 130 static int delete_device(struct chnl_net *dev)
 131 {
 132         ASSERT_RTNL();
 133         if (dev->netdev)
 134                 unregister_netdevice(dev->netdev);
 135         return 0;
 136 }
 137
 138 static void close_work(struct work_struct *work)
 139 {
 140         struct chnl_net *dev = NULL;
 141         struct list_head *list_node;
 142         struct list_head *_tmp;
 143
 144         rtnl_lock();
 145         list_for_each_safe(list_node, _tmp, &chnl_net_list) {
 146                 dev = list_entry(list_node, struct chnl_net, list_field);
 147                 if (dev->state == CAIF_SHUTDOWN)
 148                         dev_close(dev->netdev);
 149         }
 150         rtnl_unlock();
 151 }
 152 static DECLARE_WORK(close_worker, close_work);
 153
 154 static void chnl_hold(struct cflayer *lyr)
 155 {
 156         struct chnl_net *priv = container_of(lyr, struct chnl_net, chnl);
 157         dev_hold(priv->netdev);
 158 }
 159
 160 static void chnl_put(struct cflayer *lyr)
 161 {
 162         struct chnl_net *priv = container_of(lyr, struct chnl_net, chnl);
 163         dev_put(priv->netdev);
 164 }
 165
 166 static void chnl_flowctrl_cb(struct cflayer *layr, enum caif_ctrlcmd flow,
 167                              int phyid)
 168 {
 169         struct chnl_net *priv = container_of(layr, struct chnl_net, chnl);
 170         pr_debug("NET flowctrl func called flow: %s\n",
 171                 flow == CAIF_CTRLCMD_FLOW_ON_IND ? "ON" :
 172                 flow == CAIF_CTRLCMD_INIT_RSP ? "INIT" :
 173                 flow == CAIF_CTRLCMD_FLOW_OFF_IND ? "OFF" :
 174                 flow == CAIF_CTRLCMD_DEINIT_RSP ? "CLOSE/DEINIT" :
 175                 flow == CAIF_CTRLCMD_INIT_FAIL_RSP ? "OPEN_FAIL" :
 176                 flow == CAIF_CTRLCMD_REMOTE_SHUTDOWN_IND ?
 177                  "REMOTE_SHUTDOWN" : "UNKNOWN CTRL COMMAND");
 178
 179
 180
 181         switch (flow) {
 182         case CAIF_CTRLCMD_FLOW_OFF_IND:
 183                 priv->flowenabled = false;
 184                 netif_stop_queue(priv->netdev);
 185                 break;
 186         case CAIF_CTRLCMD_DEINIT_RSP:
 187                 priv->state = CAIF_DISCONNECTED;
 188                 break;
 189         case CAIF_CTRLCMD_INIT_FAIL_RSP:
 190                 priv->state = CAIF_DISCONNECTED;
 191                 wake_up_interruptible(&priv->netmgmt_wq);
 192                 break;
 193         case CAIF_CTRLCMD_REMOTE_SHUTDOWN_IND:
 194                 priv->state = CAIF_SHUTDOWN;
 195                 netif_tx_disable(priv->netdev);
 196                 schedule_work(&close_worker);
 197                 break;
 198         case CAIF_CTRLCMD_FLOW_ON_IND:
 199                 priv->flowenabled = true;
 200                 netif_wake_queue(priv->netdev);
 201                 break;
 202         case CAIF_CTRLCMD_INIT_RSP:
 203                 caif_client_register_refcnt(&priv->chnl, chnl_hold, chnl_put);
 204                 priv->state = CAIF_CONNECTED;
 205                 priv->flowenabled = true;
 206                 netif_wake_queue(priv->netdev);
 207                 wake_up_interruptible(&priv->netmgmt_wq);
 208                 break;
 209         default:
 210                 break;
 211         }
 212 }
 213
 214 static int chnl_net_start_xmit(struct sk_buff *skb, struct net_device *dev)
 215 {
 216         struct chnl_net *priv;
 217         struct cfpkt *pkt = NULL;
 218         int len;
 219         int result = -1;
 220         /* Get our private data. */
 221         priv = netdev_priv(dev);
 222
 223         if (skb->len > priv->netdev->mtu) {
 224                 pr_warn("Size of skb exceeded MTU\n");
 225                 kfree_skb(skb);
 226                 dev->stats.tx_errors++;
 227                 return NETDEV_TX_OK;
 228         }
 229
 230         if (!priv->flowenabled) {
 231                 pr_debug("dropping packets flow off\n");
 232                 kfree_skb(skb);
 233                 dev->stats.tx_dropped++;
 234                 return NETDEV_TX_OK;
 235         }
 236
 237         if (priv->conn_req.protocol == CAIFPROTO_DATAGRAM_LOOP)
 238                 swap(ip_hdr(skb)->saddr, ip_hdr(skb)->daddr);
 239
 240         /* Store original SKB length. */
 241         len = skb->len;
 242
 243         pkt = cfpkt_fromnative(CAIF_DIR_OUT, (void *) skb);
 244
 245         /* Send the packet down the stack. */
 246         result = priv->chnl.dn->transmit(priv->chnl.dn, pkt);
 247         if (result) {
 248                 dev->stats.tx_dropped++;
 249                 return NETDEV_TX_OK;
 250         }
 251
 252         /* Update statistics. */
 253         dev->stats.tx_packets++;
 254         dev->stats.tx_bytes += len;
 255
 256         return NETDEV_TX_OK;
 257 }
 258
 259 static int chnl_net_open(struct net_device *dev)
 260 {
 261         struct chnl_net *priv = NULL;
 262         int result = -1;
 263         int llifindex, headroom, tailroom, mtu;
 264         struct net_device *lldev;
 265         ASSERT_RTNL();
 266         priv = netdev_priv(dev);
 267         if (!priv) {
 268                 pr_debug("chnl_net_open: no priv\n");
 269                 return -ENODEV;
 270         }
 271
 272         if (priv->state != CAIF_CONNECTING) {
 273                 priv->state = CAIF_CONNECTING;
 274                 result = caif_connect_client(dev_net(dev), &priv->conn_req,
 275                                                 &priv->chnl, &llifindex,
 276                                                 &headroom, &tailroom);
 277                 if (result != 0) {
 278                                 pr_debug("err: "
 279                                          "Unable to register and open device,"
 280                                          " Err:%d\n",
 281                                          result);
 282                                 goto error;
 283                 }
 284
 285                 lldev = __dev_get_by_index(dev_net(dev), llifindex);
 286
 287                 if (lldev == NULL) {
 288                         pr_debug("no interface?\n");
 289                         result = -ENODEV;
 290                         goto error;
 291                 }
 292
 293                 dev->needed_tailroom = tailroom + lldev->needed_tailroom;
 294                 dev->hard_header_len = headroom + lldev->hard_header_len +
 295                         lldev->needed_tailroom;
 296
 297                 /*
 298                  * MTU, head-room etc is not know before we have a
 299                  * CAIF link layer device available. MTU calculation may
 300                  * override initial RTNL configuration.
 301                  * MTU is minimum of current mtu, link layer mtu pluss
 302                  * CAIF head and tail, and PDP GPRS contexts max MTU.
 303                  */
 304                 mtu = min_t(int, dev->mtu, lldev->mtu - (headroom + tailroom));
 305                 mtu = min_t(int, GPRS_PDP_MTU, mtu);
 306                 dev_set_mtu(dev, mtu);
 307
 308                 if (mtu < 100) {
 309                         pr_warn("CAIF Interface MTU too small (%d)\n", mtu);
 310                         result = -ENODEV;
 311                         goto error;
 312                 }
 313         }
 314
 315         rtnl_unlock();  /* Release RTNL lock during connect wait */
 316
 317         result = wait_event_interruptible_timeout(priv->netmgmt_wq,
 318                                                 priv->state != CAIF_CONNECTING,
 319                                                 CONNECT_TIMEOUT);
 320
 321         rtnl_lock();
 322
 323         if (result == -ERESTARTSYS) {
 324                 pr_debug("wait_event_interruptible woken by a signal\n");
 325                 result = -ERESTARTSYS;
 326                 goto error;
 327         }
 328
 329         if (result == 0) {
 330                 pr_debug("connect timeout\n");
 331                 caif_disconnect_client(dev_net(dev), &priv->chnl);
 332                 priv->state = CAIF_DISCONNECTED;
 333                 pr_debug("state disconnected\n");
 334                 result = -ETIMEDOUT;
 335                 goto error;
 336         }
 337
 338         if (priv->state != CAIF_CONNECTED) {
 339                 pr_debug("connect failed\n");
 340                 result = -ECONNREFUSED;
 341                 goto error;
 342         }
 343         pr_debug("CAIF Netdevice connected\n");
 344         return 0;
 345
 346 error:
 347         caif_disconnect_client(dev_net(dev), &priv->chnl);
 348         priv->state = CAIF_DISCONNECTED;
 349         pr_debug("state disconnected\n");
 350         return result;
 351
 352 }
 353
 354 static int chnl_net_stop(struct net_device *dev)
 355 {
 356         struct chnl_net *priv;
 357
 358         ASSERT_RTNL();
 359         priv = netdev_priv(dev);
 360         priv->state = CAIF_DISCONNECTED;
 361         caif_disconnect_client(dev_net(dev), &priv->chnl);
 362         return 0;
 363 }
 364
 365 static int chnl_net_init(struct net_device *dev)
 366 {
 367         struct chnl_net *priv;
 368         ASSERT_RTNL();
 369         priv = netdev_priv(dev);
 370         strncpy(priv->name, dev->name, sizeof(priv->name));
 371         return 0;
 372 }
 373
 374 static void chnl_net_uninit(struct net_device *dev)
 375 {
 376         struct chnl_net *priv;
 377         ASSERT_RTNL();
 378         priv = netdev_priv(dev);
 379         robust_list_del(&priv->list_field);
 380 }
 381
 382 static const struct net_device_ops netdev_ops = {
 383         .ndo_open = chnl_net_open,
 384         .ndo_stop = chnl_net_stop,
 385         .ndo_init = chnl_net_init,
 386         .ndo_uninit = chnl_net_uninit,
 387         .ndo_start_xmit = chnl_net_start_xmit,
 388 };
 389
 390 static void chnl_net_destructor(struct net_device *dev)
 391 {
 392         struct chnl_net *priv = netdev_priv(dev);
 393         caif_free_client(&priv->chnl);
 394 }
 395
 396 static void ipcaif_net_setup(struct net_device *dev)
 397 {
 398         struct chnl_net *priv;
 399         dev->netdev_ops = &netdev_ops;
 400         dev->needs_free_netdev = true;
 401         dev->priv_destructor = chnl_net_destructor;
 402         dev->flags |= IFF_NOARP;
 403         dev->flags |= IFF_POINTOPOINT;
 404         dev->mtu = GPRS_PDP_MTU;
 405         dev->tx_queue_len = CAIF_NET_DEFAULT_QUEUE_LEN;
 406
 407         priv = netdev_priv(dev);
 408         priv->chnl.receive = chnl_recv_cb;
 409         priv->chnl.ctrlcmd = chnl_flowctrl_cb;
 410         priv->netdev = dev;
 411         priv->conn_req.protocol = CAIFPROTO_DATAGRAM;
 412         priv->conn_req.link_selector = CAIF_LINK_HIGH_BANDW;
 413         priv->conn_req.priority = CAIF_PRIO_LOW;
 414         /* Insert illegal value */
 415         priv->conn_req.sockaddr.u.dgm.connection_id = UNDEF_CONNID;
 416         priv->flowenabled = false;
 417
 418         init_waitqueue_head(&priv->netmgmt_wq);
 419 }
 420
 421
 422 static int ipcaif_fill_info(struct sk_buff *skb, const struct net_device *dev)
 423 {
 424         struct chnl_net *priv;
 425         u8 loop;
 426         priv = netdev_priv(dev);
 427         if (nla_put_u32(skb, IFLA_CAIF_IPV4_CONNID,
 428                         priv->conn_req.sockaddr.u.dgm.connection_id) ||
 429             nla_put_u32(skb, IFLA_CAIF_IPV6_CONNID,
 430                         priv->conn_req.sockaddr.u.dgm.connection_id))
 431                 goto nla_put_failure;
 432         loop = priv->conn_req.protocol == CAIFPROTO_DATAGRAM_LOOP;
 433         if (nla_put_u8(skb, IFLA_CAIF_LOOPBACK, loop))
 434                 goto nla_put_failure;
 435         return 0;
 436 nla_put_failure:
 437         return -EMSGSIZE;
 438
 439 }
 440
 441 static void caif_netlink_parms(struct nlattr *data[],
 442                                struct caif_connect_request *conn_req)
 443 {
 444         if (!data) {
 445                 pr_warn("no params data found\n");
 446                 return;
 447         }
 448         if (data[IFLA_CAIF_IPV4_CONNID])
 449                 conn_req->sockaddr.u.dgm.connection_id =
 450                         nla_get_u32(data[IFLA_CAIF_IPV4_CONNID]);
 451         if (data[IFLA_CAIF_IPV6_CONNID])
 452                 conn_req->sockaddr.u.dgm.connection_id =
 453                         nla_get_u32(data[IFLA_CAIF_IPV6_CONNID]);
 454         if (data[IFLA_CAIF_LOOPBACK]) {
 455                 if (nla_get_u8(data[IFLA_CAIF_LOOPBACK]))
 456                         conn_req->protocol = CAIFPROTO_DATAGRAM_LOOP;
 457                 else
 458                         conn_req->protocol = CAIFPROTO_DATAGRAM;
 459         }
 460 }
 461
 462 static int ipcaif_newlink(struct net *src_net, struct net_device *dev,
 463                           struct nlattr *tb[], struct nlattr *data[],
 464                           struct netlink_ext_ack *extack)
 465 {
 466         int ret;
 467         struct chnl_net *caifdev;
 468         ASSERT_RTNL();
 469         caifdev = netdev_priv(dev);
 470         caif_netlink_parms(data, &caifdev->conn_req);
 471
 472         ret = register_netdevice(dev);
 473         if (ret)
 474                 pr_warn("device rtml registration failed\n");
 475         else
 476                 list_add(&caifdev->list_field, &chnl_net_list);
 477
 478         /* Use ifindex as connection id, and use loopback channel default. */
 479         if (caifdev->conn_req.sockaddr.u.dgm.connection_id == UNDEF_CONNID) {
 480                 caifdev->conn_req.sockaddr.u.dgm.connection_id = dev->ifindex;
 481                 caifdev->conn_req.protocol = CAIFPROTO_DATAGRAM_LOOP;
 482         }
 483         return ret;
 484 }
 485
 486 static int ipcaif_changelink(struct net_device *dev, struct nlattr *tb[],
 487                              struct nlattr *data[],
 488                              struct netlink_ext_ack *extack)
 489 {
 490         struct chnl_net *caifdev;
 491         ASSERT_RTNL();
 492         caifdev = netdev_priv(dev);
 493         caif_netlink_parms(data, &caifdev->conn_req);
 494         netdev_state_change(dev);
 495         return 0;
 496 }
 497
 498 static size_t ipcaif_get_size(const struct net_device *dev)
 499 {
 500         return
 501                 /* IFLA_CAIF_IPV4_CONNID */
 502                 nla_total_size(4) +
 503                 /* IFLA_CAIF_IPV6_CONNID */
 504                 nla_total_size(4) +
 505                 /* IFLA_CAIF_LOOPBACK */
 506                 nla_total_size(2) +
 507                 0;
 508 }
 509
 510 static const struct nla_policy ipcaif_policy[IFLA_CAIF_MAX + 1] = {
 511         [IFLA_CAIF_IPV4_CONNID]       = { .type = NLA_U32 },
 512         [IFLA_CAIF_IPV6_CONNID]       = { .type = NLA_U32 },
 513         [IFLA_CAIF_LOOPBACK]          = { .type = NLA_U8 }
 514 };
 515
 516
 517 static struct rtnl_link_ops ipcaif_link_ops __read_mostly = {
 518         .kind           = "caif",
 519         .priv_size      = sizeof(struct chnl_net),
 520         .setup          = ipcaif_net_setup,
 521         .maxtype        = IFLA_CAIF_MAX,
 522         .policy         = ipcaif_policy,
 523         .newlink        = ipcaif_newlink,
 524         .changelink     = ipcaif_changelink,
 525         .get_size       = ipcaif_get_size,
 526         .fill_info      = ipcaif_fill_info,
 527
 528 };
 529
 530 static int __init chnl_init_module(void)
 531 {
 532         return rtnl_link_register(&ipcaif_link_ops);
 533 }
 534
 535 static void __exit chnl_exit_module(void)
 536 {
 537         struct chnl_net *dev = NULL;
 538         struct list_head *list_node;
 539         struct list_head *_tmp;
 540         rtnl_link_unregister(&ipcaif_link_ops);
 541         rtnl_lock();
 542         list_for_each_safe(list_node, _tmp, &chnl_net_list) {
 543                 dev = list_entry(list_node, struct chnl_net, list_field);
 544                 list_del(list_node);
 545                 delete_device(dev);
 546         }
 547         rtnl_unlock();
 548 }
 549
 550 module_init(chnl_init_module);
 551 module_exit(chnl_exit_module);