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TOMOYO Linux Cross Reference
Linux/net/caif/chnl_net.c

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  1 /*
  2  * Copyright (C) ST-Ericsson AB 2010
  3  * Authors:     Sjur Brendeland
  4  *              Daniel Martensson
  5  * License terms: GNU General Public License (GPL) version 2
  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);
552 

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