atomic: use <linux/atomic.h>
[linux-2.6.git] / net / decnet / dn_table.c
1 /*
2  * DECnet       An implementation of the DECnet protocol suite for the LINUX
3  *              operating system.  DECnet is implemented using the  BSD Socket
4  *              interface as the means of communication with the user level.
5  *
6  *              DECnet Routing Forwarding Information Base (Routing Tables)
7  *
8  * Author:      Steve Whitehouse <SteveW@ACM.org>
9  *              Mostly copied from the IPv4 routing code
10  *
11  *
12  * Changes:
13  *
14  */
15 #include <linux/string.h>
16 #include <linux/net.h>
17 #include <linux/socket.h>
18 #include <linux/slab.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/atomic.h>
29 #include <asm/uaccess.h>
30 #include <linux/route.h> /* RTF_xxx */
31 #include <net/neighbour.h>
32 #include <net/netlink.h>
33 #include <net/dst.h>
34 #include <net/flow.h>
35 #include <net/fib_rules.h>
36 #include <net/dn.h>
37 #include <net/dn_route.h>
38 #include <net/dn_fib.h>
39 #include <net/dn_neigh.h>
40 #include <net/dn_dev.h>
41
42 struct dn_zone
43 {
44         struct dn_zone          *dz_next;
45         struct dn_fib_node      **dz_hash;
46         int                     dz_nent;
47         int                     dz_divisor;
48         u32                     dz_hashmask;
49 #define DZ_HASHMASK(dz) ((dz)->dz_hashmask)
50         int                     dz_order;
51         __le16                  dz_mask;
52 #define DZ_MASK(dz)     ((dz)->dz_mask)
53 };
54
55 struct dn_hash
56 {
57         struct dn_zone  *dh_zones[17];
58         struct dn_zone  *dh_zone_list;
59 };
60
61 #define dz_key_0(key)           ((key).datum = 0)
62
63 #define for_nexthops(fi) { int nhsel; const struct dn_fib_nh *nh;\
64         for(nhsel = 0, nh = (fi)->fib_nh; nhsel < (fi)->fib_nhs; nh++, nhsel++)
65
66 #define endfor_nexthops(fi) }
67
68 #define DN_MAX_DIVISOR 1024
69 #define DN_S_ZOMBIE 1
70 #define DN_S_ACCESSED 2
71
72 #define DN_FIB_SCAN(f, fp) \
73 for( ; ((f) = *(fp)) != NULL; (fp) = &(f)->fn_next)
74
75 #define DN_FIB_SCAN_KEY(f, fp, key) \
76 for( ; ((f) = *(fp)) != NULL && dn_key_eq((f)->fn_key, (key)); (fp) = &(f)->fn_next)
77
78 #define RT_TABLE_MIN 1
79 #define DN_FIB_TABLE_HASHSZ 256
80 static struct hlist_head dn_fib_table_hash[DN_FIB_TABLE_HASHSZ];
81 static DEFINE_RWLOCK(dn_fib_tables_lock);
82
83 static struct kmem_cache *dn_hash_kmem __read_mostly;
84 static int dn_fib_hash_zombies;
85
86 static inline dn_fib_idx_t dn_hash(dn_fib_key_t key, struct dn_zone *dz)
87 {
88         u16 h = le16_to_cpu(key.datum)>>(16 - dz->dz_order);
89         h ^= (h >> 10);
90         h ^= (h >> 6);
91         h &= DZ_HASHMASK(dz);
92         return *(dn_fib_idx_t *)&h;
93 }
94
95 static inline dn_fib_key_t dz_key(__le16 dst, struct dn_zone *dz)
96 {
97         dn_fib_key_t k;
98         k.datum = dst & DZ_MASK(dz);
99         return k;
100 }
101
102 static inline struct dn_fib_node **dn_chain_p(dn_fib_key_t key, struct dn_zone *dz)
103 {
104         return &dz->dz_hash[dn_hash(key, dz).datum];
105 }
106
107 static inline struct dn_fib_node *dz_chain(dn_fib_key_t key, struct dn_zone *dz)
108 {
109         return dz->dz_hash[dn_hash(key, dz).datum];
110 }
111
112 static inline int dn_key_eq(dn_fib_key_t a, dn_fib_key_t b)
113 {
114         return a.datum == b.datum;
115 }
116
117 static inline int dn_key_leq(dn_fib_key_t a, dn_fib_key_t b)
118 {
119         return a.datum <= b.datum;
120 }
121
122 static inline void dn_rebuild_zone(struct dn_zone *dz,
123                                    struct dn_fib_node **old_ht,
124                                    int old_divisor)
125 {
126         struct dn_fib_node *f, **fp, *next;
127         int i;
128
129         for(i = 0; i < old_divisor; i++) {
130                 for(f = old_ht[i]; f; f = next) {
131                         next = f->fn_next;
132                         for(fp = dn_chain_p(f->fn_key, dz);
133                                 *fp && dn_key_leq((*fp)->fn_key, f->fn_key);
134                                 fp = &(*fp)->fn_next)
135                                 /* NOTHING */;
136                         f->fn_next = *fp;
137                         *fp = f;
138                 }
139         }
140 }
141
142 static void dn_rehash_zone(struct dn_zone *dz)
143 {
144         struct dn_fib_node **ht, **old_ht;
145         int old_divisor, new_divisor;
146         u32 new_hashmask;
147
148         old_divisor = dz->dz_divisor;
149
150         switch (old_divisor) {
151         case 16:
152                 new_divisor = 256;
153                 new_hashmask = 0xFF;
154                 break;
155         default:
156                 printk(KERN_DEBUG "DECnet: dn_rehash_zone: BUG! %d\n",
157                        old_divisor);
158         case 256:
159                 new_divisor = 1024;
160                 new_hashmask = 0x3FF;
161                 break;
162         }
163
164         ht = kcalloc(new_divisor, sizeof(struct dn_fib_node*), GFP_KERNEL);
165         if (ht == NULL)
166                 return;
167
168         write_lock_bh(&dn_fib_tables_lock);
169         old_ht = dz->dz_hash;
170         dz->dz_hash = ht;
171         dz->dz_hashmask = new_hashmask;
172         dz->dz_divisor = new_divisor;
173         dn_rebuild_zone(dz, old_ht, old_divisor);
174         write_unlock_bh(&dn_fib_tables_lock);
175         kfree(old_ht);
176 }
177
178 static void dn_free_node(struct dn_fib_node *f)
179 {
180         dn_fib_release_info(DN_FIB_INFO(f));
181         kmem_cache_free(dn_hash_kmem, f);
182 }
183
184
185 static struct dn_zone *dn_new_zone(struct dn_hash *table, int z)
186 {
187         int i;
188         struct dn_zone *dz = kzalloc(sizeof(struct dn_zone), GFP_KERNEL);
189         if (!dz)
190                 return NULL;
191
192         if (z) {
193                 dz->dz_divisor = 16;
194                 dz->dz_hashmask = 0x0F;
195         } else {
196                 dz->dz_divisor = 1;
197                 dz->dz_hashmask = 0;
198         }
199
200         dz->dz_hash = kcalloc(dz->dz_divisor, sizeof(struct dn_fib_node *), GFP_KERNEL);
201         if (!dz->dz_hash) {
202                 kfree(dz);
203                 return NULL;
204         }
205
206         dz->dz_order = z;
207         dz->dz_mask = dnet_make_mask(z);
208
209         for(i = z + 1; i <= 16; i++)
210                 if (table->dh_zones[i])
211                         break;
212
213         write_lock_bh(&dn_fib_tables_lock);
214         if (i>16) {
215                 dz->dz_next = table->dh_zone_list;
216                 table->dh_zone_list = dz;
217         } else {
218                 dz->dz_next = table->dh_zones[i]->dz_next;
219                 table->dh_zones[i]->dz_next = dz;
220         }
221         table->dh_zones[z] = dz;
222         write_unlock_bh(&dn_fib_tables_lock);
223         return dz;
224 }
225
226
227 static int dn_fib_nh_match(struct rtmsg *r, struct nlmsghdr *nlh, struct dn_kern_rta *rta, struct dn_fib_info *fi)
228 {
229         struct rtnexthop *nhp;
230         int nhlen;
231
232         if (rta->rta_priority && *rta->rta_priority != fi->fib_priority)
233                 return 1;
234
235         if (rta->rta_oif || rta->rta_gw) {
236                 if ((!rta->rta_oif || *rta->rta_oif == fi->fib_nh->nh_oif) &&
237                     (!rta->rta_gw  || memcmp(rta->rta_gw, &fi->fib_nh->nh_gw, 2) == 0))
238                         return 0;
239                 return 1;
240         }
241
242         if (rta->rta_mp == NULL)
243                 return 0;
244
245         nhp = RTA_DATA(rta->rta_mp);
246         nhlen = RTA_PAYLOAD(rta->rta_mp);
247
248         for_nexthops(fi) {
249                 int attrlen = nhlen - sizeof(struct rtnexthop);
250                 __le16 gw;
251
252                 if (attrlen < 0 || (nhlen -= nhp->rtnh_len) < 0)
253                         return -EINVAL;
254                 if (nhp->rtnh_ifindex && nhp->rtnh_ifindex != nh->nh_oif)
255                         return 1;
256                 if (attrlen) {
257                         gw = dn_fib_get_attr16(RTNH_DATA(nhp), attrlen, RTA_GATEWAY);
258
259                         if (gw && gw != nh->nh_gw)
260                                 return 1;
261                 }
262                 nhp = RTNH_NEXT(nhp);
263         } endfor_nexthops(fi);
264
265         return 0;
266 }
267
268 static inline size_t dn_fib_nlmsg_size(struct dn_fib_info *fi)
269 {
270         size_t payload = NLMSG_ALIGN(sizeof(struct rtmsg))
271                          + nla_total_size(4) /* RTA_TABLE */
272                          + nla_total_size(2) /* RTA_DST */
273                          + nla_total_size(4); /* RTA_PRIORITY */
274
275         /* space for nested metrics */
276         payload += nla_total_size((RTAX_MAX * nla_total_size(4)));
277
278         if (fi->fib_nhs) {
279                 /* Also handles the special case fib_nhs == 1 */
280
281                 /* each nexthop is packed in an attribute */
282                 size_t nhsize = nla_total_size(sizeof(struct rtnexthop));
283
284                 /* may contain a gateway attribute */
285                 nhsize += nla_total_size(4);
286
287                 /* all nexthops are packed in a nested attribute */
288                 payload += nla_total_size(fi->fib_nhs * nhsize);
289         }
290
291         return payload;
292 }
293
294 static int dn_fib_dump_info(struct sk_buff *skb, u32 pid, u32 seq, int event,
295                         u32 tb_id, u8 type, u8 scope, void *dst, int dst_len,
296                         struct dn_fib_info *fi, unsigned int flags)
297 {
298         struct rtmsg *rtm;
299         struct nlmsghdr *nlh;
300         unsigned char *b = skb_tail_pointer(skb);
301
302         nlh = NLMSG_NEW(skb, pid, seq, event, sizeof(*rtm), flags);
303         rtm = NLMSG_DATA(nlh);
304         rtm->rtm_family = AF_DECnet;
305         rtm->rtm_dst_len = dst_len;
306         rtm->rtm_src_len = 0;
307         rtm->rtm_tos = 0;
308         rtm->rtm_table = tb_id;
309         RTA_PUT_U32(skb, RTA_TABLE, tb_id);
310         rtm->rtm_flags = fi->fib_flags;
311         rtm->rtm_scope = scope;
312         rtm->rtm_type  = type;
313         if (rtm->rtm_dst_len)
314                 RTA_PUT(skb, RTA_DST, 2, dst);
315         rtm->rtm_protocol = fi->fib_protocol;
316         if (fi->fib_priority)
317                 RTA_PUT(skb, RTA_PRIORITY, 4, &fi->fib_priority);
318         if (rtnetlink_put_metrics(skb, fi->fib_metrics) < 0)
319                 goto rtattr_failure;
320         if (fi->fib_nhs == 1) {
321                 if (fi->fib_nh->nh_gw)
322                         RTA_PUT(skb, RTA_GATEWAY, 2, &fi->fib_nh->nh_gw);
323                 if (fi->fib_nh->nh_oif)
324                         RTA_PUT(skb, RTA_OIF, sizeof(int), &fi->fib_nh->nh_oif);
325         }
326         if (fi->fib_nhs > 1) {
327                 struct rtnexthop *nhp;
328                 struct rtattr *mp_head;
329                 if (skb_tailroom(skb) <= RTA_SPACE(0))
330                         goto rtattr_failure;
331                 mp_head = (struct rtattr *)skb_put(skb, RTA_SPACE(0));
332
333                 for_nexthops(fi) {
334                         if (skb_tailroom(skb) < RTA_ALIGN(RTA_ALIGN(sizeof(*nhp)) + 4))
335                                 goto rtattr_failure;
336                         nhp = (struct rtnexthop *)skb_put(skb, RTA_ALIGN(sizeof(*nhp)));
337                         nhp->rtnh_flags = nh->nh_flags & 0xFF;
338                         nhp->rtnh_hops = nh->nh_weight - 1;
339                         nhp->rtnh_ifindex = nh->nh_oif;
340                         if (nh->nh_gw)
341                                 RTA_PUT(skb, RTA_GATEWAY, 2, &nh->nh_gw);
342                         nhp->rtnh_len = skb_tail_pointer(skb) - (unsigned char *)nhp;
343                 } endfor_nexthops(fi);
344                 mp_head->rta_type = RTA_MULTIPATH;
345                 mp_head->rta_len = skb_tail_pointer(skb) - (u8 *)mp_head;
346         }
347
348         nlh->nlmsg_len = skb_tail_pointer(skb) - b;
349         return skb->len;
350
351
352 nlmsg_failure:
353 rtattr_failure:
354         nlmsg_trim(skb, b);
355         return -EMSGSIZE;
356 }
357
358
359 static void dn_rtmsg_fib(int event, struct dn_fib_node *f, int z, u32 tb_id,
360                         struct nlmsghdr *nlh, struct netlink_skb_parms *req)
361 {
362         struct sk_buff *skb;
363         u32 pid = req ? req->pid : 0;
364         int err = -ENOBUFS;
365
366         skb = nlmsg_new(dn_fib_nlmsg_size(DN_FIB_INFO(f)), GFP_KERNEL);
367         if (skb == NULL)
368                 goto errout;
369
370         err = dn_fib_dump_info(skb, pid, nlh->nlmsg_seq, event, tb_id,
371                                f->fn_type, f->fn_scope, &f->fn_key, z,
372                                DN_FIB_INFO(f), 0);
373         if (err < 0) {
374                 /* -EMSGSIZE implies BUG in dn_fib_nlmsg_size() */
375                 WARN_ON(err == -EMSGSIZE);
376                 kfree_skb(skb);
377                 goto errout;
378         }
379         rtnl_notify(skb, &init_net, pid, RTNLGRP_DECnet_ROUTE, nlh, GFP_KERNEL);
380         return;
381 errout:
382         if (err < 0)
383                 rtnl_set_sk_err(&init_net, RTNLGRP_DECnet_ROUTE, err);
384 }
385
386 static __inline__ int dn_hash_dump_bucket(struct sk_buff *skb,
387                                 struct netlink_callback *cb,
388                                 struct dn_fib_table *tb,
389                                 struct dn_zone *dz,
390                                 struct dn_fib_node *f)
391 {
392         int i, s_i;
393
394         s_i = cb->args[4];
395         for(i = 0; f; i++, f = f->fn_next) {
396                 if (i < s_i)
397                         continue;
398                 if (f->fn_state & DN_S_ZOMBIE)
399                         continue;
400                 if (dn_fib_dump_info(skb, NETLINK_CB(cb->skb).pid,
401                                 cb->nlh->nlmsg_seq,
402                                 RTM_NEWROUTE,
403                                 tb->n,
404                                 (f->fn_state & DN_S_ZOMBIE) ? 0 : f->fn_type,
405                                 f->fn_scope, &f->fn_key, dz->dz_order,
406                                 f->fn_info, NLM_F_MULTI) < 0) {
407                         cb->args[4] = i;
408                         return -1;
409                 }
410         }
411         cb->args[4] = i;
412         return skb->len;
413 }
414
415 static __inline__ int dn_hash_dump_zone(struct sk_buff *skb,
416                                 struct netlink_callback *cb,
417                                 struct dn_fib_table *tb,
418                                 struct dn_zone *dz)
419 {
420         int h, s_h;
421
422         s_h = cb->args[3];
423         for(h = 0; h < dz->dz_divisor; h++) {
424                 if (h < s_h)
425                         continue;
426                 if (h > s_h)
427                         memset(&cb->args[4], 0, sizeof(cb->args) - 4*sizeof(cb->args[0]));
428                 if (dz->dz_hash == NULL || dz->dz_hash[h] == NULL)
429                         continue;
430                 if (dn_hash_dump_bucket(skb, cb, tb, dz, dz->dz_hash[h]) < 0) {
431                         cb->args[3] = h;
432                         return -1;
433                 }
434         }
435         cb->args[3] = h;
436         return skb->len;
437 }
438
439 static int dn_fib_table_dump(struct dn_fib_table *tb, struct sk_buff *skb,
440                                 struct netlink_callback *cb)
441 {
442         int m, s_m;
443         struct dn_zone *dz;
444         struct dn_hash *table = (struct dn_hash *)tb->data;
445
446         s_m = cb->args[2];
447         read_lock(&dn_fib_tables_lock);
448         for(dz = table->dh_zone_list, m = 0; dz; dz = dz->dz_next, m++) {
449                 if (m < s_m)
450                         continue;
451                 if (m > s_m)
452                         memset(&cb->args[3], 0, sizeof(cb->args) - 3*sizeof(cb->args[0]));
453
454                 if (dn_hash_dump_zone(skb, cb, tb, dz) < 0) {
455                         cb->args[2] = m;
456                         read_unlock(&dn_fib_tables_lock);
457                         return -1;
458                 }
459         }
460         read_unlock(&dn_fib_tables_lock);
461         cb->args[2] = m;
462
463         return skb->len;
464 }
465
466 int dn_fib_dump(struct sk_buff *skb, struct netlink_callback *cb)
467 {
468         struct net *net = sock_net(skb->sk);
469         unsigned int h, s_h;
470         unsigned int e = 0, s_e;
471         struct dn_fib_table *tb;
472         struct hlist_node *node;
473         int dumped = 0;
474
475         if (!net_eq(net, &init_net))
476                 return 0;
477
478         if (NLMSG_PAYLOAD(cb->nlh, 0) >= sizeof(struct rtmsg) &&
479                 ((struct rtmsg *)NLMSG_DATA(cb->nlh))->rtm_flags&RTM_F_CLONED)
480                         return dn_cache_dump(skb, cb);
481
482         s_h = cb->args[0];
483         s_e = cb->args[1];
484
485         for (h = s_h; h < DN_FIB_TABLE_HASHSZ; h++, s_h = 0) {
486                 e = 0;
487                 hlist_for_each_entry(tb, node, &dn_fib_table_hash[h], hlist) {
488                         if (e < s_e)
489                                 goto next;
490                         if (dumped)
491                                 memset(&cb->args[2], 0, sizeof(cb->args) -
492                                                  2 * sizeof(cb->args[0]));
493                         if (tb->dump(tb, skb, cb) < 0)
494                                 goto out;
495                         dumped = 1;
496 next:
497                         e++;
498                 }
499         }
500 out:
501         cb->args[1] = e;
502         cb->args[0] = h;
503
504         return skb->len;
505 }
506
507 static int dn_fib_table_insert(struct dn_fib_table *tb, struct rtmsg *r, struct dn_kern_rta *rta, struct nlmsghdr *n, struct netlink_skb_parms *req)
508 {
509         struct dn_hash *table = (struct dn_hash *)tb->data;
510         struct dn_fib_node *new_f, *f, **fp, **del_fp;
511         struct dn_zone *dz;
512         struct dn_fib_info *fi;
513         int z = r->rtm_dst_len;
514         int type = r->rtm_type;
515         dn_fib_key_t key;
516         int err;
517
518         if (z > 16)
519                 return -EINVAL;
520
521         dz = table->dh_zones[z];
522         if (!dz && !(dz = dn_new_zone(table, z)))
523                 return -ENOBUFS;
524
525         dz_key_0(key);
526         if (rta->rta_dst) {
527                 __le16 dst;
528                 memcpy(&dst, rta->rta_dst, 2);
529                 if (dst & ~DZ_MASK(dz))
530                         return -EINVAL;
531                 key = dz_key(dst, dz);
532         }
533
534         if ((fi = dn_fib_create_info(r, rta, n, &err)) == NULL)
535                 return err;
536
537         if (dz->dz_nent > (dz->dz_divisor << 2) &&
538                         dz->dz_divisor > DN_MAX_DIVISOR &&
539                         (z==16 || (1<<z) > dz->dz_divisor))
540                 dn_rehash_zone(dz);
541
542         fp = dn_chain_p(key, dz);
543
544         DN_FIB_SCAN(f, fp) {
545                 if (dn_key_leq(key, f->fn_key))
546                         break;
547         }
548
549         del_fp = NULL;
550
551         if (f && (f->fn_state & DN_S_ZOMBIE) &&
552                         dn_key_eq(f->fn_key, key)) {
553                 del_fp = fp;
554                 fp = &f->fn_next;
555                 f = *fp;
556                 goto create;
557         }
558
559         DN_FIB_SCAN_KEY(f, fp, key) {
560                 if (fi->fib_priority <= DN_FIB_INFO(f)->fib_priority)
561                         break;
562         }
563
564         if (f && dn_key_eq(f->fn_key, key) &&
565                         fi->fib_priority == DN_FIB_INFO(f)->fib_priority) {
566                 struct dn_fib_node **ins_fp;
567
568                 err = -EEXIST;
569                 if (n->nlmsg_flags & NLM_F_EXCL)
570                         goto out;
571
572                 if (n->nlmsg_flags & NLM_F_REPLACE) {
573                         del_fp = fp;
574                         fp = &f->fn_next;
575                         f = *fp;
576                         goto replace;
577                 }
578
579                 ins_fp = fp;
580                 err = -EEXIST;
581
582                 DN_FIB_SCAN_KEY(f, fp, key) {
583                         if (fi->fib_priority != DN_FIB_INFO(f)->fib_priority)
584                                 break;
585                         if (f->fn_type == type &&
586                             f->fn_scope == r->rtm_scope &&
587                             DN_FIB_INFO(f) == fi)
588                                 goto out;
589                 }
590
591                 if (!(n->nlmsg_flags & NLM_F_APPEND)) {
592                         fp = ins_fp;
593                         f = *fp;
594                 }
595         }
596
597 create:
598         err = -ENOENT;
599         if (!(n->nlmsg_flags & NLM_F_CREATE))
600                 goto out;
601
602 replace:
603         err = -ENOBUFS;
604         new_f = kmem_cache_zalloc(dn_hash_kmem, GFP_KERNEL);
605         if (new_f == NULL)
606                 goto out;
607
608         new_f->fn_key = key;
609         new_f->fn_type = type;
610         new_f->fn_scope = r->rtm_scope;
611         DN_FIB_INFO(new_f) = fi;
612
613         new_f->fn_next = f;
614         write_lock_bh(&dn_fib_tables_lock);
615         *fp = new_f;
616         write_unlock_bh(&dn_fib_tables_lock);
617         dz->dz_nent++;
618
619         if (del_fp) {
620                 f = *del_fp;
621                 write_lock_bh(&dn_fib_tables_lock);
622                 *del_fp = f->fn_next;
623                 write_unlock_bh(&dn_fib_tables_lock);
624
625                 if (!(f->fn_state & DN_S_ZOMBIE))
626                         dn_rtmsg_fib(RTM_DELROUTE, f, z, tb->n, n, req);
627                 if (f->fn_state & DN_S_ACCESSED)
628                         dn_rt_cache_flush(-1);
629                 dn_free_node(f);
630                 dz->dz_nent--;
631         } else {
632                 dn_rt_cache_flush(-1);
633         }
634
635         dn_rtmsg_fib(RTM_NEWROUTE, new_f, z, tb->n, n, req);
636
637         return 0;
638 out:
639         dn_fib_release_info(fi);
640         return err;
641 }
642
643
644 static int dn_fib_table_delete(struct dn_fib_table *tb, struct rtmsg *r, struct dn_kern_rta *rta, struct nlmsghdr *n, struct netlink_skb_parms *req)
645 {
646         struct dn_hash *table = (struct dn_hash*)tb->data;
647         struct dn_fib_node **fp, **del_fp, *f;
648         int z = r->rtm_dst_len;
649         struct dn_zone *dz;
650         dn_fib_key_t key;
651         int matched;
652
653
654         if (z > 16)
655                 return -EINVAL;
656
657         if ((dz = table->dh_zones[z]) == NULL)
658                 return -ESRCH;
659
660         dz_key_0(key);
661         if (rta->rta_dst) {
662                 __le16 dst;
663                 memcpy(&dst, rta->rta_dst, 2);
664                 if (dst & ~DZ_MASK(dz))
665                         return -EINVAL;
666                 key = dz_key(dst, dz);
667         }
668
669         fp = dn_chain_p(key, dz);
670
671         DN_FIB_SCAN(f, fp) {
672                 if (dn_key_eq(f->fn_key, key))
673                         break;
674                 if (dn_key_leq(key, f->fn_key))
675                         return -ESRCH;
676         }
677
678         matched = 0;
679         del_fp = NULL;
680         DN_FIB_SCAN_KEY(f, fp, key) {
681                 struct dn_fib_info *fi = DN_FIB_INFO(f);
682
683                 if (f->fn_state & DN_S_ZOMBIE)
684                         return -ESRCH;
685
686                 matched++;
687
688                 if (del_fp == NULL &&
689                                 (!r->rtm_type || f->fn_type == r->rtm_type) &&
690                                 (r->rtm_scope == RT_SCOPE_NOWHERE || f->fn_scope == r->rtm_scope) &&
691                                 (!r->rtm_protocol ||
692                                         fi->fib_protocol == r->rtm_protocol) &&
693                                 dn_fib_nh_match(r, n, rta, fi) == 0)
694                         del_fp = fp;
695         }
696
697         if (del_fp) {
698                 f = *del_fp;
699                 dn_rtmsg_fib(RTM_DELROUTE, f, z, tb->n, n, req);
700
701                 if (matched != 1) {
702                         write_lock_bh(&dn_fib_tables_lock);
703                         *del_fp = f->fn_next;
704                         write_unlock_bh(&dn_fib_tables_lock);
705
706                         if (f->fn_state & DN_S_ACCESSED)
707                                 dn_rt_cache_flush(-1);
708                         dn_free_node(f);
709                         dz->dz_nent--;
710                 } else {
711                         f->fn_state |= DN_S_ZOMBIE;
712                         if (f->fn_state & DN_S_ACCESSED) {
713                                 f->fn_state &= ~DN_S_ACCESSED;
714                                 dn_rt_cache_flush(-1);
715                         }
716                         if (++dn_fib_hash_zombies > 128)
717                                 dn_fib_flush();
718                 }
719
720                 return 0;
721         }
722
723         return -ESRCH;
724 }
725
726 static inline int dn_flush_list(struct dn_fib_node **fp, int z, struct dn_hash *table)
727 {
728         int found = 0;
729         struct dn_fib_node *f;
730
731         while((f = *fp) != NULL) {
732                 struct dn_fib_info *fi = DN_FIB_INFO(f);
733
734                 if (fi && ((f->fn_state & DN_S_ZOMBIE) || (fi->fib_flags & RTNH_F_DEAD))) {
735                         write_lock_bh(&dn_fib_tables_lock);
736                         *fp = f->fn_next;
737                         write_unlock_bh(&dn_fib_tables_lock);
738
739                         dn_free_node(f);
740                         found++;
741                         continue;
742                 }
743                 fp = &f->fn_next;
744         }
745
746         return found;
747 }
748
749 static int dn_fib_table_flush(struct dn_fib_table *tb)
750 {
751         struct dn_hash *table = (struct dn_hash *)tb->data;
752         struct dn_zone *dz;
753         int found = 0;
754
755         dn_fib_hash_zombies = 0;
756         for(dz = table->dh_zone_list; dz; dz = dz->dz_next) {
757                 int i;
758                 int tmp = 0;
759                 for(i = dz->dz_divisor-1; i >= 0; i--)
760                         tmp += dn_flush_list(&dz->dz_hash[i], dz->dz_order, table);
761                 dz->dz_nent -= tmp;
762                 found += tmp;
763         }
764
765         return found;
766 }
767
768 static int dn_fib_table_lookup(struct dn_fib_table *tb, const struct flowidn *flp, struct dn_fib_res *res)
769 {
770         int err;
771         struct dn_zone *dz;
772         struct dn_hash *t = (struct dn_hash *)tb->data;
773
774         read_lock(&dn_fib_tables_lock);
775         for(dz = t->dh_zone_list; dz; dz = dz->dz_next) {
776                 struct dn_fib_node *f;
777                 dn_fib_key_t k = dz_key(flp->daddr, dz);
778
779                 for(f = dz_chain(k, dz); f; f = f->fn_next) {
780                         if (!dn_key_eq(k, f->fn_key)) {
781                                 if (dn_key_leq(k, f->fn_key))
782                                         break;
783                                 else
784                                         continue;
785                         }
786
787                         f->fn_state |= DN_S_ACCESSED;
788
789                         if (f->fn_state&DN_S_ZOMBIE)
790                                 continue;
791
792                         if (f->fn_scope < flp->flowidn_scope)
793                                 continue;
794
795                         err = dn_fib_semantic_match(f->fn_type, DN_FIB_INFO(f), flp, res);
796
797                         if (err == 0) {
798                                 res->type = f->fn_type;
799                                 res->scope = f->fn_scope;
800                                 res->prefixlen = dz->dz_order;
801                                 goto out;
802                         }
803                         if (err < 0)
804                                 goto out;
805                 }
806         }
807         err = 1;
808 out:
809         read_unlock(&dn_fib_tables_lock);
810         return err;
811 }
812
813
814 struct dn_fib_table *dn_fib_get_table(u32 n, int create)
815 {
816         struct dn_fib_table *t;
817         struct hlist_node *node;
818         unsigned int h;
819
820         if (n < RT_TABLE_MIN)
821                 return NULL;
822
823         if (n > RT_TABLE_MAX)
824                 return NULL;
825
826         h = n & (DN_FIB_TABLE_HASHSZ - 1);
827         rcu_read_lock();
828         hlist_for_each_entry_rcu(t, node, &dn_fib_table_hash[h], hlist) {
829                 if (t->n == n) {
830                         rcu_read_unlock();
831                         return t;
832                 }
833         }
834         rcu_read_unlock();
835
836         if (!create)
837                 return NULL;
838
839         if (in_interrupt() && net_ratelimit()) {
840                 printk(KERN_DEBUG "DECnet: BUG! Attempt to create routing table from interrupt\n");
841                 return NULL;
842         }
843
844         t = kzalloc(sizeof(struct dn_fib_table) + sizeof(struct dn_hash),
845                     GFP_KERNEL);
846         if (t == NULL)
847                 return NULL;
848
849         t->n = n;
850         t->insert = dn_fib_table_insert;
851         t->delete = dn_fib_table_delete;
852         t->lookup = dn_fib_table_lookup;
853         t->flush  = dn_fib_table_flush;
854         t->dump = dn_fib_table_dump;
855         hlist_add_head_rcu(&t->hlist, &dn_fib_table_hash[h]);
856
857         return t;
858 }
859
860 struct dn_fib_table *dn_fib_empty_table(void)
861 {
862         u32 id;
863
864         for(id = RT_TABLE_MIN; id <= RT_TABLE_MAX; id++)
865                 if (dn_fib_get_table(id, 0) == NULL)
866                         return dn_fib_get_table(id, 1);
867         return NULL;
868 }
869
870 void dn_fib_flush(void)
871 {
872         int flushed = 0;
873         struct dn_fib_table *tb;
874         struct hlist_node *node;
875         unsigned int h;
876
877         for (h = 0; h < DN_FIB_TABLE_HASHSZ; h++) {
878                 hlist_for_each_entry(tb, node, &dn_fib_table_hash[h], hlist)
879                         flushed += tb->flush(tb);
880         }
881
882         if (flushed)
883                 dn_rt_cache_flush(-1);
884 }
885
886 void __init dn_fib_table_init(void)
887 {
888         dn_hash_kmem = kmem_cache_create("dn_fib_info_cache",
889                                         sizeof(struct dn_fib_info),
890                                         0, SLAB_HWCACHE_ALIGN,
891                                         NULL);
892 }
893
894 void __exit dn_fib_table_cleanup(void)
895 {
896         struct dn_fib_table *t;
897         struct hlist_node *node, *next;
898         unsigned int h;
899
900         write_lock(&dn_fib_tables_lock);
901         for (h = 0; h < DN_FIB_TABLE_HASHSZ; h++) {
902                 hlist_for_each_entry_safe(t, node, next, &dn_fib_table_hash[h],
903                                           hlist) {
904                         hlist_del(&t->hlist);
905                         kfree(t);
906                 }
907         }
908         write_unlock(&dn_fib_tables_lock);
909 }