6986be754ef284cb0f023e3d08c3c4321ad31af9
[linux-3.10.git] / net / decnet / dn_rules.c
1
2 /*
3  * DECnet       An implementation of the DECnet protocol suite for the LINUX
4  *              operating system.  DECnet is implemented using the  BSD Socket
5  *              interface as the means of communication with the user level.
6  *
7  *              DECnet Routing Forwarding Information Base (Rules)
8  *
9  * Author:      Steve Whitehouse <SteveW@ACM.org>
10  *              Mostly copied from Alexey Kuznetsov's ipv4/fib_rules.c
11  *
12  *
13  * Changes:
14  *
15  */
16 #include <linux/string.h>
17 #include <linux/net.h>
18 #include <linux/socket.h>
19 #include <linux/sockios.h>
20 #include <linux/init.h>
21 #include <linux/skbuff.h>
22 #include <linux/netlink.h>
23 #include <linux/rtnetlink.h>
24 #include <linux/proc_fs.h>
25 #include <linux/netdevice.h>
26 #include <linux/timer.h>
27 #include <linux/spinlock.h>
28 #include <linux/in_route.h>
29 #include <linux/list.h>
30 #include <linux/rcupdate.h>
31 #include <asm/atomic.h>
32 #include <asm/uaccess.h>
33 #include <net/neighbour.h>
34 #include <net/dst.h>
35 #include <net/flow.h>
36 #include <net/dn.h>
37 #include <net/dn_fib.h>
38 #include <net/dn_neigh.h>
39 #include <net/dn_dev.h>
40
41 struct dn_fib_rule
42 {
43         struct hlist_node       r_hlist;
44         atomic_t                r_clntref;
45         u32                     r_preference;
46         unsigned char           r_table;
47         unsigned char           r_action;
48         unsigned char           r_dst_len;
49         unsigned char           r_src_len;
50         __le16                  r_src;
51         __le16                  r_srcmask;
52         __le16                  r_dst;
53         __le16                  r_dstmask;
54         __le16                  r_srcmap;
55         u8                      r_flags;
56 #ifdef CONFIG_DECNET_ROUTE_FWMARK
57         u32                     r_fwmark;
58 #endif
59         int                     r_ifindex;
60         char                    r_ifname[IFNAMSIZ];
61         int                     r_dead;
62         struct rcu_head         rcu;
63 };
64
65 static struct dn_fib_rule default_rule = {
66         .r_clntref =            ATOMIC_INIT(2),
67         .r_preference =         0x7fff,
68         .r_table =              RT_TABLE_MAIN,
69         .r_action =             RTN_UNICAST
70 };
71
72 static struct hlist_head dn_fib_rules;
73
74 int dn_fib_rtm_delrule(struct sk_buff *skb, struct nlmsghdr *nlh, void *arg)
75 {
76         struct rtattr **rta = arg;
77         struct rtmsg *rtm = NLMSG_DATA(nlh);
78         struct dn_fib_rule *r;
79         struct hlist_node *node;
80         int err = -ESRCH;
81
82         hlist_for_each_entry(r, node, &dn_fib_rules, r_hlist) {
83                 if ((!rta[RTA_SRC-1] || memcmp(RTA_DATA(rta[RTA_SRC-1]), &r->r_src, 2) == 0) &&
84                         rtm->rtm_src_len == r->r_src_len &&
85                         rtm->rtm_dst_len == r->r_dst_len &&
86                         (!rta[RTA_DST-1] || memcmp(RTA_DATA(rta[RTA_DST-1]), &r->r_dst, 2) == 0) &&
87 #ifdef CONFIG_DECNET_ROUTE_FWMARK
88                         (!rta[RTA_PROTOINFO-1] || memcmp(RTA_DATA(rta[RTA_PROTOINFO-1]), &r->r_fwmark, 4) == 0) &&
89 #endif
90                         (!rtm->rtm_type || rtm->rtm_type == r->r_action) &&
91                         (!rta[RTA_PRIORITY-1] || memcmp(RTA_DATA(rta[RTA_PRIORITY-1]), &r->r_preference, 4) == 0) &&
92                         (!rta[RTA_IIF-1] || rtattr_strcmp(rta[RTA_IIF-1], r->r_ifname) == 0) &&
93                         (!rtm->rtm_table || (r && rtm->rtm_table == r->r_table))) {
94
95                         err = -EPERM;
96                         if (r == &default_rule)
97                                 break;
98
99                         hlist_del_rcu(&r->r_hlist);
100                         r->r_dead = 1;
101                         dn_fib_rule_put(r);
102                         err = 0;
103                         break;
104                 }
105         }
106
107         return err;
108 }
109
110 static inline void dn_fib_rule_put_rcu(struct rcu_head *head)
111 {
112         struct dn_fib_rule *r = container_of(head, struct dn_fib_rule, rcu);
113         kfree(r);
114 }
115
116 void dn_fib_rule_put(struct dn_fib_rule *r)
117 {
118         if (atomic_dec_and_test(&r->r_clntref)) {
119                 if (r->r_dead)
120                         call_rcu(&r->rcu, dn_fib_rule_put_rcu);
121                 else
122                         printk(KERN_DEBUG "Attempt to free alive dn_fib_rule\n");
123         }
124 }
125
126
127 int dn_fib_rtm_newrule(struct sk_buff *skb, struct nlmsghdr *nlh, void *arg)
128 {
129         struct rtattr **rta = arg;
130         struct rtmsg *rtm = NLMSG_DATA(nlh);
131         struct dn_fib_rule *r, *new_r, *last = NULL;
132         struct hlist_node *node = NULL;
133         unsigned char table_id;
134
135         if (rtm->rtm_src_len > 16 || rtm->rtm_dst_len > 16)
136                 return -EINVAL;
137
138         if (rta[RTA_IIF-1] && RTA_PAYLOAD(rta[RTA_IIF-1]) > IFNAMSIZ)
139                 return -EINVAL;
140
141         if (rtm->rtm_type == RTN_NAT)
142                 return -EINVAL;
143
144         table_id = rtm->rtm_table;
145         if (table_id == RT_TABLE_UNSPEC) {
146                 struct dn_fib_table *tb;
147                 if (rtm->rtm_type == RTN_UNICAST) {
148                         if ((tb = dn_fib_empty_table()) == NULL)
149                                 return -ENOBUFS;
150                         table_id = tb->n;
151                 }
152         }
153
154         new_r = kzalloc(sizeof(*new_r), GFP_KERNEL);
155         if (!new_r)
156                 return -ENOMEM;
157
158         if (rta[RTA_SRC-1])
159                 memcpy(&new_r->r_src, RTA_DATA(rta[RTA_SRC-1]), 2);
160         if (rta[RTA_DST-1])
161                 memcpy(&new_r->r_dst, RTA_DATA(rta[RTA_DST-1]), 2);
162         if (rta[RTA_GATEWAY-1])
163                 memcpy(&new_r->r_srcmap, RTA_DATA(rta[RTA_GATEWAY-1]), 2);
164         new_r->r_src_len = rtm->rtm_src_len;
165         new_r->r_dst_len = rtm->rtm_dst_len;
166         new_r->r_srcmask = dnet_make_mask(rtm->rtm_src_len);
167         new_r->r_dstmask = dnet_make_mask(rtm->rtm_dst_len);
168 #ifdef CONFIG_DECNET_ROUTE_FWMARK
169         if (rta[RTA_PROTOINFO-1])
170                 memcpy(&new_r->r_fwmark, RTA_DATA(rta[RTA_PROTOINFO-1]), 4);
171 #endif
172         new_r->r_action = rtm->rtm_type;
173         new_r->r_flags = rtm->rtm_flags;
174         if (rta[RTA_PRIORITY-1])
175                 memcpy(&new_r->r_preference, RTA_DATA(rta[RTA_PRIORITY-1]), 4);
176         new_r->r_table = table_id;
177         if (rta[RTA_IIF-1]) {
178                 struct net_device *dev;
179                 rtattr_strlcpy(new_r->r_ifname, rta[RTA_IIF-1], IFNAMSIZ);
180                 new_r->r_ifindex = -1;
181                 dev = dev_get_by_name(new_r->r_ifname);
182                 if (dev) {
183                         new_r->r_ifindex = dev->ifindex;
184                         dev_put(dev);
185                 }
186         }
187
188         r = container_of(dn_fib_rules.first, struct dn_fib_rule, r_hlist);
189         if (!new_r->r_preference) {
190                 if (r && r->r_hlist.next != NULL) {
191                         r = container_of(r->r_hlist.next, struct dn_fib_rule, r_hlist);
192                         if (r->r_preference)
193                                 new_r->r_preference = r->r_preference - 1;
194                 }
195         }
196
197         hlist_for_each_entry(r, node, &dn_fib_rules, r_hlist) {
198                 if (r->r_preference > new_r->r_preference)
199                         break;
200                 last = r;
201         }
202         atomic_inc(&new_r->r_clntref);
203
204         if (last)
205                 hlist_add_after_rcu(&last->r_hlist, &new_r->r_hlist);
206         else
207                 hlist_add_before_rcu(&new_r->r_hlist, &r->r_hlist);
208         return 0;
209 }
210
211
212 int dn_fib_lookup(const struct flowi *flp, struct dn_fib_res *res)
213 {
214         struct dn_fib_rule *r, *policy;
215         struct dn_fib_table *tb;
216         __le16 saddr = flp->fld_src;
217         __le16 daddr = flp->fld_dst;
218         struct hlist_node *node;
219         int err;
220
221         rcu_read_lock();
222
223         hlist_for_each_entry_rcu(r, node, &dn_fib_rules, r_hlist) {
224                 if (((saddr^r->r_src) & r->r_srcmask) ||
225                     ((daddr^r->r_dst) & r->r_dstmask) ||
226 #ifdef CONFIG_DECNET_ROUTE_FWMARK
227                     (r->r_fwmark && r->r_fwmark != flp->fld_fwmark) ||
228 #endif
229                     (r->r_ifindex && r->r_ifindex != flp->iif))
230                         continue;
231
232                 switch(r->r_action) {
233                         case RTN_UNICAST:
234                         case RTN_NAT:
235                                 policy = r;
236                                 break;
237                         case RTN_UNREACHABLE:
238                                 rcu_read_unlock();
239                                 return -ENETUNREACH;
240                         default:
241                         case RTN_BLACKHOLE:
242                                 rcu_read_unlock();
243                                 return -EINVAL;
244                         case RTN_PROHIBIT:
245                                 rcu_read_unlock();
246                                 return -EACCES;
247                 }
248
249                 if ((tb = dn_fib_get_table(r->r_table, 0)) == NULL)
250                         continue;
251                 err = tb->lookup(tb, flp, res);
252                 if (err == 0) {
253                         res->r = policy;
254                         if (policy)
255                                 atomic_inc(&policy->r_clntref);
256                         rcu_read_unlock();
257                         return 0;
258                 }
259                 if (err < 0 && err != -EAGAIN) {
260                         rcu_read_unlock();
261                         return err;
262                 }
263         }
264
265         rcu_read_unlock();
266         return -ESRCH;
267 }
268
269 unsigned dnet_addr_type(__le16 addr)
270 {
271         struct flowi fl = { .nl_u = { .dn_u = { .daddr = addr } } };
272         struct dn_fib_res res;
273         unsigned ret = RTN_UNICAST;
274         struct dn_fib_table *tb = dn_fib_tables[RT_TABLE_LOCAL];
275
276         res.r = NULL;
277
278         if (tb) {
279                 if (!tb->lookup(tb, &fl, &res)) {
280                         ret = res.type;
281                         dn_fib_res_put(&res);
282                 }
283         }
284         return ret;
285 }
286
287 __le16 dn_fib_rules_policy(__le16 saddr, struct dn_fib_res *res, unsigned *flags)
288 {
289         struct dn_fib_rule *r = res->r;
290
291         if (r->r_action == RTN_NAT) {
292                 int addrtype = dnet_addr_type(r->r_srcmap);
293
294                 if (addrtype == RTN_NAT) {
295                         saddr = (saddr&~r->r_srcmask)|r->r_srcmap;
296                         *flags |= RTCF_SNAT;
297                 } else if (addrtype == RTN_LOCAL || r->r_srcmap == 0) {
298                         saddr = r->r_srcmap;
299                         *flags |= RTCF_MASQ;
300                 }
301         }
302         return saddr;
303 }
304
305 static void dn_fib_rules_detach(struct net_device *dev)
306 {
307         struct hlist_node *node;
308         struct dn_fib_rule *r;
309
310         hlist_for_each_entry(r, node, &dn_fib_rules, r_hlist) {
311                 if (r->r_ifindex == dev->ifindex)
312                         r->r_ifindex = -1;
313         }
314 }
315
316 static void dn_fib_rules_attach(struct net_device *dev)
317 {
318         struct hlist_node *node;
319         struct dn_fib_rule *r;
320
321         hlist_for_each_entry(r, node, &dn_fib_rules, r_hlist) {
322                 if (r->r_ifindex == -1 && strcmp(dev->name, r->r_ifname) == 0)
323                         r->r_ifindex = dev->ifindex;
324         }
325 }
326
327 static int dn_fib_rules_event(struct notifier_block *this, unsigned long event, void *ptr)
328 {
329         struct net_device *dev = ptr;
330
331         switch(event) {
332                 case NETDEV_UNREGISTER:
333                         dn_fib_rules_detach(dev);
334                         dn_fib_sync_down(0, dev, 1);
335                 case NETDEV_REGISTER:
336                         dn_fib_rules_attach(dev);
337                         dn_fib_sync_up(dev);
338         }
339
340         return NOTIFY_DONE;
341 }
342
343
344 static struct notifier_block dn_fib_rules_notifier = {
345         .notifier_call =        dn_fib_rules_event,
346 };
347
348 static int dn_fib_fill_rule(struct sk_buff *skb, struct dn_fib_rule *r,
349                             struct netlink_callback *cb, unsigned int flags)
350 {
351         struct rtmsg *rtm;
352         struct nlmsghdr *nlh;
353         unsigned char *b = skb->tail;
354
355
356         nlh = NLMSG_NEW_ANSWER(skb, cb, RTM_NEWRULE, sizeof(*rtm), flags);
357         rtm = NLMSG_DATA(nlh);
358         rtm->rtm_family = AF_DECnet;
359         rtm->rtm_dst_len = r->r_dst_len;
360         rtm->rtm_src_len = r->r_src_len;
361         rtm->rtm_tos = 0;
362 #ifdef CONFIG_DECNET_ROUTE_FWMARK
363         if (r->r_fwmark)
364                 RTA_PUT(skb, RTA_PROTOINFO, 4, &r->r_fwmark);
365 #endif
366         rtm->rtm_table = r->r_table;
367         rtm->rtm_protocol = 0;
368         rtm->rtm_scope = 0;
369         rtm->rtm_type = r->r_action;
370         rtm->rtm_flags = r->r_flags;
371
372         if (r->r_dst_len)
373                 RTA_PUT(skb, RTA_DST, 2, &r->r_dst);
374         if (r->r_src_len)
375                 RTA_PUT(skb, RTA_SRC, 2, &r->r_src);
376         if (r->r_ifname[0])
377                 RTA_PUT(skb, RTA_IIF, IFNAMSIZ, &r->r_ifname);
378         if (r->r_preference)
379                 RTA_PUT(skb, RTA_PRIORITY, 4, &r->r_preference);
380         if (r->r_srcmap)
381                 RTA_PUT(skb, RTA_GATEWAY, 2, &r->r_srcmap);
382         nlh->nlmsg_len = skb->tail - b;
383         return skb->len;
384
385 nlmsg_failure:
386 rtattr_failure:
387         skb_trim(skb, b - skb->data);
388         return -1;
389 }
390
391 int dn_fib_dump_rules(struct sk_buff *skb, struct netlink_callback *cb)
392 {
393         int idx = 0;
394         int s_idx = cb->args[0];
395         struct dn_fib_rule *r;
396         struct hlist_node *node;
397
398         rcu_read_lock();
399         hlist_for_each_entry(r, node, &dn_fib_rules, r_hlist) {
400                 if (idx < s_idx)
401                         goto next;
402                 if (dn_fib_fill_rule(skb, r, cb, NLM_F_MULTI) < 0)
403                         break;
404 next:
405                 idx++;
406         }
407         rcu_read_unlock();
408         cb->args[0] = idx;
409
410         return skb->len;
411 }
412
413 void __init dn_fib_rules_init(void)
414 {
415         INIT_HLIST_HEAD(&dn_fib_rules);
416         hlist_add_head(&default_rule.r_hlist, &dn_fib_rules);
417         register_netdevice_notifier(&dn_fib_rules_notifier);
418 }
419
420 void __exit dn_fib_rules_cleanup(void)
421 {
422         unregister_netdevice_notifier(&dn_fib_rules_notifier);
423 }
424
425