a3e842fd0f9c15a7d4d310bcdec4cd37bbeb4cfa
[linux-3.10.git] / net / batman-adv / gateway_client.c
1 /*
2  * Copyright (C) 2009-2011 B.A.T.M.A.N. contributors:
3  *
4  * Marek Lindner
5  *
6  * This program is free software; you can redistribute it and/or
7  * modify it under the terms of version 2 of the GNU General Public
8  * License as published by the Free Software Foundation.
9  *
10  * This program is distributed in the hope that it will be useful, but
11  * WITHOUT ANY WARRANTY; without even the implied warranty of
12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13  * General Public License for more details.
14  *
15  * You should have received a copy of the GNU General Public License
16  * along with this program; if not, write to the Free Software
17  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
18  * 02110-1301, USA
19  *
20  */
21
22 #include "main.h"
23 #include "gateway_client.h"
24 #include "gateway_common.h"
25 #include "hard-interface.h"
26 #include <linux/ip.h>
27 #include <linux/ipv6.h>
28 #include <linux/udp.h>
29 #include <linux/if_vlan.h>
30
31 static void gw_node_free_rcu(struct rcu_head *rcu)
32 {
33         struct gw_node *gw_node;
34
35         gw_node = container_of(rcu, struct gw_node, rcu);
36         kfree(gw_node);
37 }
38
39 static void gw_node_free_ref(struct gw_node *gw_node)
40 {
41         if (atomic_dec_and_test(&gw_node->refcount))
42                 call_rcu(&gw_node->rcu, gw_node_free_rcu);
43 }
44
45 void *gw_get_selected(struct bat_priv *bat_priv)
46 {
47         struct gw_node *curr_gateway_tmp;
48         struct orig_node *orig_node = NULL;
49
50         rcu_read_lock();
51         curr_gateway_tmp = rcu_dereference(bat_priv->curr_gw);
52         if (!curr_gateway_tmp)
53                 goto out;
54
55         orig_node = curr_gateway_tmp->orig_node;
56
57 out:
58         rcu_read_unlock();
59         return orig_node;
60 }
61
62 void gw_deselect(struct bat_priv *bat_priv)
63 {
64         struct gw_node *gw_node;
65
66         spin_lock_bh(&bat_priv->gw_list_lock);
67         gw_node = rcu_dereference(bat_priv->curr_gw);
68         rcu_assign_pointer(bat_priv->curr_gw, NULL);
69         spin_unlock_bh(&bat_priv->gw_list_lock);
70
71         if (gw_node)
72                 gw_node_free_ref(gw_node);
73 }
74
75 static void gw_select(struct bat_priv *bat_priv, struct gw_node *new_gw_node)
76 {
77         struct gw_node *curr_gw_node;
78
79         if (new_gw_node && !atomic_inc_not_zero(&new_gw_node->refcount))
80                 new_gw_node = NULL;
81
82         spin_lock_bh(&bat_priv->gw_list_lock);
83         curr_gw_node = rcu_dereference(bat_priv->curr_gw);
84         rcu_assign_pointer(bat_priv->curr_gw, new_gw_node);
85         spin_unlock_bh(&bat_priv->gw_list_lock);
86
87         if (curr_gw_node)
88                 gw_node_free_ref(curr_gw_node);
89 }
90
91 void gw_election(struct bat_priv *bat_priv)
92 {
93         struct hlist_node *node;
94         struct gw_node *gw_node, *curr_gw, *curr_gw_tmp = NULL;
95         uint8_t max_tq = 0;
96         uint32_t max_gw_factor = 0, tmp_gw_factor = 0;
97         int down, up;
98
99         /**
100          * The batman daemon checks here if we already passed a full originator
101          * cycle in order to make sure we don't choose the first gateway we
102          * hear about. This check is based on the daemon's uptime which we
103          * don't have.
104          **/
105         if (atomic_read(&bat_priv->gw_mode) != GW_MODE_CLIENT)
106                 return;
107
108         rcu_read_lock();
109         curr_gw = rcu_dereference(bat_priv->curr_gw);
110         if (curr_gw) {
111                 rcu_read_unlock();
112                 return;
113         }
114
115         if (hlist_empty(&bat_priv->gw_list)) {
116
117                 if (curr_gw) {
118                         rcu_read_unlock();
119                         bat_dbg(DBG_BATMAN, bat_priv,
120                                 "Removing selected gateway - "
121                                 "no gateway in range\n");
122                         gw_deselect(bat_priv);
123                 } else
124                         rcu_read_unlock();
125
126                 return;
127         }
128
129         hlist_for_each_entry_rcu(gw_node, node, &bat_priv->gw_list, list) {
130                 if (!gw_node->orig_node->router)
131                         continue;
132
133                 if (gw_node->deleted)
134                         continue;
135
136                 switch (atomic_read(&bat_priv->gw_sel_class)) {
137                 case 1: /* fast connection */
138                         gw_bandwidth_to_kbit(gw_node->orig_node->gw_flags,
139                                              &down, &up);
140
141                         tmp_gw_factor = (gw_node->orig_node->router->tq_avg *
142                                          gw_node->orig_node->router->tq_avg *
143                                          down * 100 * 100) /
144                                          (TQ_LOCAL_WINDOW_SIZE *
145                                          TQ_LOCAL_WINDOW_SIZE * 64);
146
147                         if ((tmp_gw_factor > max_gw_factor) ||
148                             ((tmp_gw_factor == max_gw_factor) &&
149                              (gw_node->orig_node->router->tq_avg > max_tq)))
150                                 curr_gw_tmp = gw_node;
151                         break;
152
153                 default: /**
154                           * 2:  stable connection (use best statistic)
155                           * 3:  fast-switch (use best statistic but change as
156                           *     soon as a better gateway appears)
157                           * XX: late-switch (use best statistic but change as
158                           *     soon as a better gateway appears which has
159                           *     $routing_class more tq points)
160                           **/
161                         if (gw_node->orig_node->router->tq_avg > max_tq)
162                                 curr_gw_tmp = gw_node;
163                         break;
164                 }
165
166                 if (gw_node->orig_node->router->tq_avg > max_tq)
167                         max_tq = gw_node->orig_node->router->tq_avg;
168
169                 if (tmp_gw_factor > max_gw_factor)
170                         max_gw_factor = tmp_gw_factor;
171         }
172
173         if (curr_gw != curr_gw_tmp) {
174                 if ((curr_gw) && (!curr_gw_tmp))
175                         bat_dbg(DBG_BATMAN, bat_priv,
176                                 "Removing selected gateway - "
177                                 "no gateway in range\n");
178                 else if ((!curr_gw) && (curr_gw_tmp))
179                         bat_dbg(DBG_BATMAN, bat_priv,
180                                 "Adding route to gateway %pM "
181                                 "(gw_flags: %i, tq: %i)\n",
182                                 curr_gw_tmp->orig_node->orig,
183                                 curr_gw_tmp->orig_node->gw_flags,
184                                 curr_gw_tmp->orig_node->router->tq_avg);
185                 else
186                         bat_dbg(DBG_BATMAN, bat_priv,
187                                 "Changing route to gateway %pM "
188                                 "(gw_flags: %i, tq: %i)\n",
189                                 curr_gw_tmp->orig_node->orig,
190                                 curr_gw_tmp->orig_node->gw_flags,
191                                 curr_gw_tmp->orig_node->router->tq_avg);
192
193                 gw_select(bat_priv, curr_gw_tmp);
194         }
195
196         rcu_read_unlock();
197 }
198
199 void gw_check_election(struct bat_priv *bat_priv, struct orig_node *orig_node)
200 {
201         struct gw_node *curr_gateway_tmp;
202         uint8_t gw_tq_avg, orig_tq_avg;
203
204         rcu_read_lock();
205         curr_gateway_tmp = rcu_dereference(bat_priv->curr_gw);
206         if (!curr_gateway_tmp)
207                 goto out_rcu;
208
209         if (!curr_gateway_tmp->orig_node)
210                 goto deselect_rcu;
211
212         if (!curr_gateway_tmp->orig_node->router)
213                 goto deselect_rcu;
214
215         /* this node already is the gateway */
216         if (curr_gateway_tmp->orig_node == orig_node)
217                 goto out_rcu;
218
219         if (!orig_node->router)
220                 goto out_rcu;
221
222         gw_tq_avg = curr_gateway_tmp->orig_node->router->tq_avg;
223         rcu_read_unlock();
224
225         orig_tq_avg = orig_node->router->tq_avg;
226
227         /* the TQ value has to be better */
228         if (orig_tq_avg < gw_tq_avg)
229                 goto out;
230
231         /**
232          * if the routing class is greater than 3 the value tells us how much
233          * greater the TQ value of the new gateway must be
234          **/
235         if ((atomic_read(&bat_priv->gw_sel_class) > 3) &&
236             (orig_tq_avg - gw_tq_avg < atomic_read(&bat_priv->gw_sel_class)))
237                 goto out;
238
239         bat_dbg(DBG_BATMAN, bat_priv,
240                 "Restarting gateway selection: better gateway found (tq curr: "
241                 "%i, tq new: %i)\n",
242                 gw_tq_avg, orig_tq_avg);
243         goto deselect;
244
245 out_rcu:
246         rcu_read_unlock();
247         goto out;
248 deselect_rcu:
249         rcu_read_unlock();
250 deselect:
251         gw_deselect(bat_priv);
252 out:
253         return;
254 }
255
256 static void gw_node_add(struct bat_priv *bat_priv,
257                         struct orig_node *orig_node, uint8_t new_gwflags)
258 {
259         struct gw_node *gw_node;
260         int down, up;
261
262         gw_node = kmalloc(sizeof(struct gw_node), GFP_ATOMIC);
263         if (!gw_node)
264                 return;
265
266         memset(gw_node, 0, sizeof(struct gw_node));
267         INIT_HLIST_NODE(&gw_node->list);
268         gw_node->orig_node = orig_node;
269         atomic_set(&gw_node->refcount, 1);
270
271         spin_lock_bh(&bat_priv->gw_list_lock);
272         hlist_add_head_rcu(&gw_node->list, &bat_priv->gw_list);
273         spin_unlock_bh(&bat_priv->gw_list_lock);
274
275         gw_bandwidth_to_kbit(new_gwflags, &down, &up);
276         bat_dbg(DBG_BATMAN, bat_priv,
277                 "Found new gateway %pM -> gw_class: %i - %i%s/%i%s\n",
278                 orig_node->orig, new_gwflags,
279                 (down > 2048 ? down / 1024 : down),
280                 (down > 2048 ? "MBit" : "KBit"),
281                 (up > 2048 ? up / 1024 : up),
282                 (up > 2048 ? "MBit" : "KBit"));
283 }
284
285 void gw_node_update(struct bat_priv *bat_priv,
286                     struct orig_node *orig_node, uint8_t new_gwflags)
287 {
288         struct hlist_node *node;
289         struct gw_node *gw_node;
290
291         rcu_read_lock();
292         hlist_for_each_entry_rcu(gw_node, node, &bat_priv->gw_list, list) {
293                 if (gw_node->orig_node != orig_node)
294                         continue;
295
296                 bat_dbg(DBG_BATMAN, bat_priv,
297                         "Gateway class of originator %pM changed from "
298                         "%i to %i\n",
299                         orig_node->orig, gw_node->orig_node->gw_flags,
300                         new_gwflags);
301
302                 gw_node->deleted = 0;
303
304                 if (new_gwflags == 0) {
305                         gw_node->deleted = jiffies;
306                         bat_dbg(DBG_BATMAN, bat_priv,
307                                 "Gateway %pM removed from gateway list\n",
308                                 orig_node->orig);
309
310                         if (gw_node == rcu_dereference(bat_priv->curr_gw)) {
311                                 rcu_read_unlock();
312                                 gw_deselect(bat_priv);
313                                 return;
314                         }
315                 }
316
317                 rcu_read_unlock();
318                 return;
319         }
320         rcu_read_unlock();
321
322         if (new_gwflags == 0)
323                 return;
324
325         gw_node_add(bat_priv, orig_node, new_gwflags);
326 }
327
328 void gw_node_delete(struct bat_priv *bat_priv, struct orig_node *orig_node)
329 {
330         return gw_node_update(bat_priv, orig_node, 0);
331 }
332
333 void gw_node_purge(struct bat_priv *bat_priv)
334 {
335         struct gw_node *gw_node;
336         struct hlist_node *node, *node_tmp;
337         unsigned long timeout = 2 * PURGE_TIMEOUT * HZ;
338
339         spin_lock_bh(&bat_priv->gw_list_lock);
340
341         hlist_for_each_entry_safe(gw_node, node, node_tmp,
342                                   &bat_priv->gw_list, list) {
343                 if (((!gw_node->deleted) ||
344                      (time_before(jiffies, gw_node->deleted + timeout))) &&
345                     atomic_read(&bat_priv->mesh_state) == MESH_ACTIVE)
346                         continue;
347
348                 if (rcu_dereference(bat_priv->curr_gw) == gw_node)
349                         gw_deselect(bat_priv);
350
351                 hlist_del_rcu(&gw_node->list);
352                 gw_node_free_ref(gw_node);
353         }
354
355
356         spin_unlock_bh(&bat_priv->gw_list_lock);
357 }
358
359 static int _write_buffer_text(struct bat_priv *bat_priv,
360                               struct seq_file *seq, struct gw_node *gw_node)
361 {
362         struct gw_node *curr_gw;
363         int down, up, ret;
364
365         gw_bandwidth_to_kbit(gw_node->orig_node->gw_flags, &down, &up);
366
367         rcu_read_lock();
368         curr_gw = rcu_dereference(bat_priv->curr_gw);
369
370         ret = seq_printf(seq, "%s %pM (%3i) %pM [%10s]: %3i - %i%s/%i%s\n",
371                        (curr_gw == gw_node ? "=>" : "  "),
372                        gw_node->orig_node->orig,
373                        gw_node->orig_node->router->tq_avg,
374                        gw_node->orig_node->router->addr,
375                        gw_node->orig_node->router->if_incoming->net_dev->name,
376                        gw_node->orig_node->gw_flags,
377                        (down > 2048 ? down / 1024 : down),
378                        (down > 2048 ? "MBit" : "KBit"),
379                        (up > 2048 ? up / 1024 : up),
380                        (up > 2048 ? "MBit" : "KBit"));
381
382         rcu_read_unlock();
383         return ret;
384 }
385
386 int gw_client_seq_print_text(struct seq_file *seq, void *offset)
387 {
388         struct net_device *net_dev = (struct net_device *)seq->private;
389         struct bat_priv *bat_priv = netdev_priv(net_dev);
390         struct gw_node *gw_node;
391         struct hlist_node *node;
392         int gw_count = 0;
393
394         if (!bat_priv->primary_if) {
395
396                 return seq_printf(seq, "BATMAN mesh %s disabled - please "
397                                   "specify interfaces to enable it\n",
398                                   net_dev->name);
399         }
400
401         if (bat_priv->primary_if->if_status != IF_ACTIVE) {
402
403                 return seq_printf(seq, "BATMAN mesh %s disabled - "
404                                        "primary interface not active\n",
405                                        net_dev->name);
406         }
407
408         seq_printf(seq, "      %-12s (%s/%i) %17s [%10s]: gw_class ... "
409                    "[B.A.T.M.A.N. adv %s%s, MainIF/MAC: %s/%pM (%s)]\n",
410                    "Gateway", "#", TQ_MAX_VALUE, "Nexthop",
411                    "outgoingIF", SOURCE_VERSION, REVISION_VERSION_STR,
412                    bat_priv->primary_if->net_dev->name,
413                    bat_priv->primary_if->net_dev->dev_addr, net_dev->name);
414
415         rcu_read_lock();
416         hlist_for_each_entry_rcu(gw_node, node, &bat_priv->gw_list, list) {
417                 if (gw_node->deleted)
418                         continue;
419
420                 if (!gw_node->orig_node->router)
421                         continue;
422
423                 _write_buffer_text(bat_priv, seq, gw_node);
424                 gw_count++;
425         }
426         rcu_read_unlock();
427
428         if (gw_count == 0)
429                 seq_printf(seq, "No gateways in range ...\n");
430
431         return 0;
432 }
433
434 int gw_is_target(struct bat_priv *bat_priv, struct sk_buff *skb)
435 {
436         struct ethhdr *ethhdr;
437         struct iphdr *iphdr;
438         struct ipv6hdr *ipv6hdr;
439         struct udphdr *udphdr;
440         unsigned int header_len = 0;
441
442         if (atomic_read(&bat_priv->gw_mode) == GW_MODE_OFF)
443                 return 0;
444
445         /* check for ethernet header */
446         if (!pskb_may_pull(skb, header_len + ETH_HLEN))
447                 return 0;
448         ethhdr = (struct ethhdr *)skb->data;
449         header_len += ETH_HLEN;
450
451         /* check for initial vlan header */
452         if (ntohs(ethhdr->h_proto) == ETH_P_8021Q) {
453                 if (!pskb_may_pull(skb, header_len + VLAN_HLEN))
454                         return 0;
455                 ethhdr = (struct ethhdr *)(skb->data + VLAN_HLEN);
456                 header_len += VLAN_HLEN;
457         }
458
459         /* check for ip header */
460         switch (ntohs(ethhdr->h_proto)) {
461         case ETH_P_IP:
462                 if (!pskb_may_pull(skb, header_len + sizeof(struct iphdr)))
463                         return 0;
464                 iphdr = (struct iphdr *)(skb->data + header_len);
465                 header_len += iphdr->ihl * 4;
466
467                 /* check for udp header */
468                 if (iphdr->protocol != IPPROTO_UDP)
469                         return 0;
470
471                 break;
472         case ETH_P_IPV6:
473                 if (!pskb_may_pull(skb, header_len + sizeof(struct ipv6hdr)))
474                         return 0;
475                 ipv6hdr = (struct ipv6hdr *)(skb->data + header_len);
476                 header_len += sizeof(struct ipv6hdr);
477
478                 /* check for udp header */
479                 if (ipv6hdr->nexthdr != IPPROTO_UDP)
480                         return 0;
481
482                 break;
483         default:
484                 return 0;
485         }
486
487         if (!pskb_may_pull(skb, header_len + sizeof(struct udphdr)))
488                 return 0;
489         udphdr = (struct udphdr *)(skb->data + header_len);
490         header_len += sizeof(struct udphdr);
491
492         /* check for bootp port */
493         if ((ntohs(ethhdr->h_proto) == ETH_P_IP) &&
494              (ntohs(udphdr->dest) != 67))
495                 return 0;
496
497         if ((ntohs(ethhdr->h_proto) == ETH_P_IPV6) &&
498             (ntohs(udphdr->dest) != 547))
499                 return 0;
500
501         if (atomic_read(&bat_priv->gw_mode) == GW_MODE_SERVER)
502                 return -1;
503
504         rcu_read_lock();
505         if (!rcu_dereference(bat_priv->curr_gw)) {
506                 rcu_read_unlock();
507                 return 0;
508         }
509         rcu_read_unlock();
510
511         return 1;
512 }