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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/hardirq.h>
 12 #include <linux/init.h>
 13 #include <linux/module.h>
 14 #include <linux/netdevice.h>
 15 #include <linux/if_ether.h>
 16 #include <linux/ip.h>
 17 #include <linux/sched.h>
 18 #include <linux/sockios.h>
 19 #include <linux/caif/if_caif.h>
 20 #include <net/rtnetlink.h>
 21 #include <net/caif/caif_layer.h>
 22 #include <net/caif/cfpkt.h>
 23 #include <net/caif/caif_dev.h>
 24 
 25 /* GPRS PDP connection has MTU to 1500 */
 26 #define GPRS_PDP_MTU 1500
 27 /* 5 sec. connect timeout */
 28 #define CONNECT_TIMEOUT (5 * HZ)
 29 #define CAIF_NET_DEFAULT_QUEUE_LEN 500
 30 #define UNDEF_CONNID 0xffffffff
 31 
 32 /*This list is protected by the rtnl lock. */
 33 static LIST_HEAD(chnl_net_list);
 34 
 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         char name[256];
 51         wait_queue_head_t netmgmt_wq;
 52         /* Flow status to remember and control the transmission. */
 53         bool flowenabled;
 54         enum caif_states state;
 55 };
 56 
 57 static void robust_list_del(struct list_head *delete_node)
 58 {
 59         struct list_head *list_node;
 60         struct list_head *n;
 61         ASSERT_RTNL();
 62         list_for_each_safe(list_node, n, &chnl_net_list) {
 63                 if (list_node == delete_node) {
 64                         list_del(list_node);
 65                         return;
 66                 }
 67         }
 68         WARN_ON(1);
 69 }
 70 
 71 static int chnl_recv_cb(struct cflayer *layr, struct cfpkt *pkt)
 72 {
 73         struct sk_buff *skb;
 74         struct chnl_net *priv;
 75         int pktlen;
 76         const u8 *ip_version;
 77         u8 buf;
 78 
 79         priv = container_of(layr, struct chnl_net, chnl);
 80         if (!priv)
 81                 return -EINVAL;
 82 
 83         skb = (struct sk_buff *) cfpkt_tonative(pkt);
 84 
 85         /* Get length of CAIF packet. */
 86         pktlen = skb->len;
 87 
 88         /* Pass some minimum information and
 89          * send the packet to the net stack.
 90          */
 91         skb->dev = priv->netdev;
 92 
 93         /* check the version of IP */
 94         ip_version = skb_header_pointer(skb, 0, 1, &buf);
 95         if (!ip_version) {
 96                 kfree_skb(skb);
 97                 return -EINVAL;
 98         }
 99 
100         switch (*ip_version >> 4) {
101         case 4:
102                 skb->protocol = htons(ETH_P_IP);
103                 break;
104         case 6:
105                 skb->protocol = htons(ETH_P_IPV6);
106                 break;
107         default:
108                 kfree_skb(skb);
109                 priv->netdev->stats.rx_errors++;
110                 return -EINVAL;
111         }
112 
113         /* If we change the header in loop mode, the checksum is corrupted. */
114         if (priv->conn_req.protocol == CAIFPROTO_DATAGRAM_LOOP)
115                 skb->ip_summed = CHECKSUM_UNNECESSARY;
116         else
117                 skb->ip_summed = CHECKSUM_NONE;
118 
119         if (in_interrupt())
120                 netif_rx(skb);
121         else
122                 netif_rx_ni(skb);
123 
124         /* Update statistics. */
125         priv->netdev->stats.rx_packets++;
126         priv->netdev->stats.rx_bytes += pktlen;
127 
128         return 0;
129 }
130 
131 static int delete_device(struct chnl_net *dev)
132 {
133         ASSERT_RTNL();
134         if (dev->netdev)
135                 unregister_netdevice(dev->netdev);
136         return 0;
137 }
138 
139 static void close_work(struct work_struct *work)
140 {
141         struct chnl_net *dev = NULL;
142         struct list_head *list_node;
143         struct list_head *_tmp;
144 
145         rtnl_lock();
146         list_for_each_safe(list_node, _tmp, &chnl_net_list) {
147                 dev = list_entry(list_node, struct chnl_net, list_field);
148                 if (dev->state == CAIF_SHUTDOWN)
149                         dev_close(dev->netdev);
150         }
151         rtnl_unlock();
152 }
153 static DECLARE_WORK(close_worker, close_work);
154 
155 static void chnl_hold(struct cflayer *lyr)
156 {
157         struct chnl_net *priv = container_of(lyr, struct chnl_net, chnl);
158         dev_hold(priv->netdev);
159 }
160 
161 static void chnl_put(struct cflayer *lyr)
162 {
163         struct chnl_net *priv = container_of(lyr, struct chnl_net, chnl);
164         dev_put(priv->netdev);
165 }
166 
167 static void chnl_flowctrl_cb(struct cflayer *layr, enum caif_ctrlcmd flow,
168                              int phyid)
169 {
170         struct chnl_net *priv = container_of(layr, struct chnl_net, chnl);
171         pr_debug("NET flowctrl func called flow: %s\n",
172                 flow == CAIF_CTRLCMD_FLOW_ON_IND ? "ON" :
173                 flow == CAIF_CTRLCMD_INIT_RSP ? "INIT" :
174                 flow == CAIF_CTRLCMD_FLOW_OFF_IND ? "OFF" :
175                 flow == CAIF_CTRLCMD_DEINIT_RSP ? "CLOSE/DEINIT" :
176                 flow == CAIF_CTRLCMD_INIT_FAIL_RSP ? "OPEN_FAIL" :
177                 flow == CAIF_CTRLCMD_REMOTE_SHUTDOWN_IND ?
178                  "REMOTE_SHUTDOWN" : "UKNOWN CTRL COMMAND");
179 
180 
181 
182         switch (flow) {
183         case CAIF_CTRLCMD_FLOW_OFF_IND:
184                 priv->flowenabled = false;
185                 netif_stop_queue(priv->netdev);
186                 break;
187         case CAIF_CTRLCMD_DEINIT_RSP:
188                 priv->state = CAIF_DISCONNECTED;
189                 break;
190         case CAIF_CTRLCMD_INIT_FAIL_RSP:
191                 priv->state = CAIF_DISCONNECTED;
192                 wake_up_interruptible(&priv->netmgmt_wq);
193                 break;
194         case CAIF_CTRLCMD_REMOTE_SHUTDOWN_IND:
195                 priv->state = CAIF_SHUTDOWN;
196                 netif_tx_disable(priv->netdev);
197                 schedule_work(&close_worker);
198                 break;
199         case CAIF_CTRLCMD_FLOW_ON_IND:
200                 priv->flowenabled = true;
201                 netif_wake_queue(priv->netdev);
202                 break;
203         case CAIF_CTRLCMD_INIT_RSP:
204                 caif_client_register_refcnt(&priv->chnl, chnl_hold, chnl_put);
205                 priv->state = CAIF_CONNECTED;
206                 priv->flowenabled = true;
207                 netif_wake_queue(priv->netdev);
208                 wake_up_interruptible(&priv->netmgmt_wq);
209                 break;
210         default:
211                 break;
212         }
213 }
214 
215 static int chnl_net_start_xmit(struct sk_buff *skb, struct net_device *dev)
216 {
217         struct chnl_net *priv;
218         struct cfpkt *pkt = NULL;
219         int len;
220         int result = -1;
221         /* Get our private data. */
222         priv = netdev_priv(dev);
223 
224         if (skb->len > priv->netdev->mtu) {
225                 pr_warn("Size of skb exceeded MTU\n");
226                 kfree_skb(skb);
227                 dev->stats.tx_errors++;
228                 return NETDEV_TX_OK;
229         }
230 
231         if (!priv->flowenabled) {
232                 pr_debug("dropping packets flow off\n");
233                 kfree_skb(skb);
234                 dev->stats.tx_dropped++;
235                 return NETDEV_TX_OK;
236         }
237 
238         if (priv->conn_req.protocol == CAIFPROTO_DATAGRAM_LOOP)
239                 swap(ip_hdr(skb)->saddr, ip_hdr(skb)->daddr);
240 
241         /* Store original SKB length. */
242         len = skb->len;
243 
244         pkt = cfpkt_fromnative(CAIF_DIR_OUT, (void *) skb);
245 
246         /* Send the packet down the stack. */
247         result = priv->chnl.dn->transmit(priv->chnl.dn, pkt);
248         if (result) {
249                 dev->stats.tx_dropped++;
250                 return NETDEV_TX_OK;
251         }
252 
253         /* Update statistics. */
254         dev->stats.tx_packets++;
255         dev->stats.tx_bytes += len;
256 
257         return NETDEV_TX_OK;
258 }
259 
260 static int chnl_net_open(struct net_device *dev)
261 {
262         struct chnl_net *priv = NULL;
263         int result = -1;
264         int llifindex, headroom, tailroom, mtu;
265         struct net_device *lldev;
266         ASSERT_RTNL();
267         priv = netdev_priv(dev);
268         if (!priv) {
269                 pr_debug("chnl_net_open: no priv\n");
270                 return -ENODEV;
271         }
272 
273         if (priv->state != CAIF_CONNECTING) {
274                 priv->state = CAIF_CONNECTING;
275                 result = caif_connect_client(dev_net(dev), &priv->conn_req,
276                                                 &priv->chnl, &llifindex,
277                                                 &headroom, &tailroom);
278                 if (result != 0) {
279                                 pr_debug("err: "
280                                          "Unable to register and open device,"
281                                          " Err:%d\n",
282                                          result);
283                                 goto error;
284                 }
285 
286                 lldev = __dev_get_by_index(dev_net(dev), llifindex);
287 
288                 if (lldev == NULL) {
289                         pr_debug("no interface?\n");
290                         result = -ENODEV;
291                         goto error;
292                 }
293 
294                 dev->needed_tailroom = tailroom + lldev->needed_tailroom;
295                 dev->hard_header_len = headroom + lldev->hard_header_len +
296                         lldev->needed_tailroom;
297 
298                 /*
299                  * MTU, head-room etc is not know before we have a
300                  * CAIF link layer device available. MTU calculation may
301                  * override initial RTNL configuration.
302                  * MTU is minimum of current mtu, link layer mtu pluss
303                  * CAIF head and tail, and PDP GPRS contexts max MTU.
304                  */
305                 mtu = min_t(int, dev->mtu, lldev->mtu - (headroom + tailroom));
306                 mtu = min_t(int, GPRS_PDP_MTU, mtu);
307                 dev_set_mtu(dev, mtu);
308 
309                 if (mtu < 100) {
310                         pr_warn("CAIF Interface MTU too small (%d)\n", mtu);
311                         result = -ENODEV;
312                         goto error;
313                 }
314         }
315 
316         rtnl_unlock();  /* Release RTNL lock during connect wait */
317 
318         result = wait_event_interruptible_timeout(priv->netmgmt_wq,
319                                                 priv->state != CAIF_CONNECTING,
320                                                 CONNECT_TIMEOUT);
321 
322         rtnl_lock();
323 
324         if (result == -ERESTARTSYS) {
325                 pr_debug("wait_event_interruptible woken by a signal\n");
326                 result = -ERESTARTSYS;
327                 goto error;
328         }
329 
330         if (result == 0) {
331                 pr_debug("connect timeout\n");
332                 caif_disconnect_client(dev_net(dev), &priv->chnl);
333                 priv->state = CAIF_DISCONNECTED;
334                 pr_debug("state disconnected\n");
335                 result = -ETIMEDOUT;
336                 goto error;
337         }
338 
339         if (priv->state != CAIF_CONNECTED) {
340                 pr_debug("connect failed\n");
341                 result = -ECONNREFUSED;
342                 goto error;
343         }
344         pr_debug("CAIF Netdevice connected\n");
345         return 0;
346 
347 error:
348         caif_disconnect_client(dev_net(dev), &priv->chnl);
349         priv->state = CAIF_DISCONNECTED;
350         pr_debug("state disconnected\n");
351         return result;
352 
353 }
354 
355 static int chnl_net_stop(struct net_device *dev)
356 {
357         struct chnl_net *priv;
358 
359         ASSERT_RTNL();
360         priv = netdev_priv(dev);
361         priv->state = CAIF_DISCONNECTED;
362         caif_disconnect_client(dev_net(dev), &priv->chnl);
363         return 0;
364 }
365 
366 static int chnl_net_init(struct net_device *dev)
367 {
368         struct chnl_net *priv;
369         ASSERT_RTNL();
370         priv = netdev_priv(dev);
371         strncpy(priv->name, dev->name, sizeof(priv->name));
372         return 0;
373 }
374 
375 static void chnl_net_uninit(struct net_device *dev)
376 {
377         struct chnl_net *priv;
378         ASSERT_RTNL();
379         priv = netdev_priv(dev);
380         robust_list_del(&priv->list_field);
381 }
382 
383 static const struct net_device_ops netdev_ops = {
384         .ndo_open = chnl_net_open,
385         .ndo_stop = chnl_net_stop,
386         .ndo_init = chnl_net_init,
387         .ndo_uninit = chnl_net_uninit,
388         .ndo_start_xmit = chnl_net_start_xmit,
389 };
390 
391 static void chnl_net_destructor(struct net_device *dev)
392 {
393         struct chnl_net *priv = netdev_priv(dev);
394         caif_free_client(&priv->chnl);
395 }
396 
397 static void ipcaif_net_setup(struct net_device *dev)
398 {
399         struct chnl_net *priv;
400         dev->netdev_ops = &netdev_ops;
401         dev->needs_free_netdev = true;
402         dev->priv_destructor = chnl_net_destructor;
403         dev->flags |= IFF_NOARP;
404         dev->flags |= IFF_POINTOPOINT;
405         dev->mtu = GPRS_PDP_MTU;
406         dev->tx_queue_len = CAIF_NET_DEFAULT_QUEUE_LEN;
407 
408         priv = netdev_priv(dev);
409         priv->chnl.receive = chnl_recv_cb;
410         priv->chnl.ctrlcmd = chnl_flowctrl_cb;
411         priv->netdev = dev;
412         priv->conn_req.protocol = CAIFPROTO_DATAGRAM;
413         priv->conn_req.link_selector = CAIF_LINK_HIGH_BANDW;
414         priv->conn_req.priority = CAIF_PRIO_LOW;
415         /* Insert illegal value */
416         priv->conn_req.sockaddr.u.dgm.connection_id = UNDEF_CONNID;
417         priv->flowenabled = false;
418 
419         init_waitqueue_head(&priv->netmgmt_wq);
420 }
421 
422 
423 static int ipcaif_fill_info(struct sk_buff *skb, const struct net_device *dev)
424 {
425         struct chnl_net *priv;
426         u8 loop;
427         priv = netdev_priv(dev);
428         if (nla_put_u32(skb, IFLA_CAIF_IPV4_CONNID,
429                         priv->conn_req.sockaddr.u.dgm.connection_id) ||
430             nla_put_u32(skb, IFLA_CAIF_IPV6_CONNID,
431                         priv->conn_req.sockaddr.u.dgm.connection_id))
432                 goto nla_put_failure;
433         loop = priv->conn_req.protocol == CAIFPROTO_DATAGRAM_LOOP;
434         if (nla_put_u8(skb, IFLA_CAIF_LOOPBACK, loop))
435                 goto nla_put_failure;
436         return 0;
437 nla_put_failure:
438         return -EMSGSIZE;
439 
440 }
441 
442 static void caif_netlink_parms(struct nlattr *data[],
443                                struct caif_connect_request *conn_req)
444 {
445         if (!data) {
446                 pr_warn("no params data found\n");
447                 return;
448         }
449         if (data[IFLA_CAIF_IPV4_CONNID])
450                 conn_req->sockaddr.u.dgm.connection_id =
451                         nla_get_u32(data[IFLA_CAIF_IPV4_CONNID]);
452         if (data[IFLA_CAIF_IPV6_CONNID])
453                 conn_req->sockaddr.u.dgm.connection_id =
454                         nla_get_u32(data[IFLA_CAIF_IPV6_CONNID]);
455         if (data[IFLA_CAIF_LOOPBACK]) {
456                 if (nla_get_u8(data[IFLA_CAIF_LOOPBACK]))
457                         conn_req->protocol = CAIFPROTO_DATAGRAM_LOOP;
458                 else
459                         conn_req->protocol = CAIFPROTO_DATAGRAM;
460         }
461 }
462 
463 static int ipcaif_newlink(struct net *src_net, struct net_device *dev,
464                           struct nlattr *tb[], struct nlattr *data[],
465                           struct netlink_ext_ack *extack)
466 {
467         int ret;
468         struct chnl_net *caifdev;
469         ASSERT_RTNL();
470         caifdev = netdev_priv(dev);
471         caif_netlink_parms(data, &caifdev->conn_req);
472 
473         ret = register_netdevice(dev);
474         if (ret)
475                 pr_warn("device rtml registration failed\n");
476         else
477                 list_add(&caifdev->list_field, &chnl_net_list);
478 
479         /* Use ifindex as connection id, and use loopback channel default. */
480         if (caifdev->conn_req.sockaddr.u.dgm.connection_id == UNDEF_CONNID) {
481                 caifdev->conn_req.sockaddr.u.dgm.connection_id = dev->ifindex;
482                 caifdev->conn_req.protocol = CAIFPROTO_DATAGRAM_LOOP;
483         }
484         return ret;
485 }
486 
487 static int ipcaif_changelink(struct net_device *dev, struct nlattr *tb[],
488                              struct nlattr *data[],
489                              struct netlink_ext_ack *extack)
490 {
491         struct chnl_net *caifdev;
492         ASSERT_RTNL();
493         caifdev = netdev_priv(dev);
494         caif_netlink_parms(data, &caifdev->conn_req);
495         netdev_state_change(dev);
496         return 0;
497 }
498 
499 static size_t ipcaif_get_size(const struct net_device *dev)
500 {
501         return
502                 /* IFLA_CAIF_IPV4_CONNID */
503                 nla_total_size(4) +
504                 /* IFLA_CAIF_IPV6_CONNID */
505                 nla_total_size(4) +
506                 /* IFLA_CAIF_LOOPBACK */
507                 nla_total_size(2) +
508                 0;
509 }
510 
511 static const struct nla_policy ipcaif_policy[IFLA_CAIF_MAX + 1] = {
512         [IFLA_CAIF_IPV4_CONNID]       = { .type = NLA_U32 },
513         [IFLA_CAIF_IPV6_CONNID]       = { .type = NLA_U32 },
514         [IFLA_CAIF_LOOPBACK]          = { .type = NLA_U8 }
515 };
516 
517 
518 static struct rtnl_link_ops ipcaif_link_ops __read_mostly = {
519         .kind           = "caif",
520         .priv_size      = sizeof(struct chnl_net),
521         .setup          = ipcaif_net_setup,
522         .maxtype        = IFLA_CAIF_MAX,
523         .policy         = ipcaif_policy,
524         .newlink        = ipcaif_newlink,
525         .changelink     = ipcaif_changelink,
526         .get_size       = ipcaif_get_size,
527         .fill_info      = ipcaif_fill_info,
528 
529 };
530 
531 static int __init chnl_init_module(void)
532 {
533         return rtnl_link_register(&ipcaif_link_ops);
534 }
535 
536 static void __exit chnl_exit_module(void)
537 {
538         struct chnl_net *dev = NULL;
539         struct list_head *list_node;
540         struct list_head *_tmp;
541         rtnl_link_unregister(&ipcaif_link_ops);
542         rtnl_lock();
543         list_for_each_safe(list_node, _tmp, &chnl_net_list) {
544                 dev = list_entry(list_node, struct chnl_net, list_field);
545                 list_del(list_node);
546                 delete_device(dev);
547         }
548         rtnl_unlock();
549 }
550 
551 module_init(chnl_init_module);
552 module_exit(chnl_exit_module);
553 

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