ipv4: fix redirect handling
[linux-2.6.git] / net / tipc / name_distr.c
1 /*
2  * net/tipc/name_distr.c: TIPC name distribution code
3  *
4  * Copyright (c) 2000-2006, Ericsson AB
5  * Copyright (c) 2005, 2010-2011, Wind River Systems
6  * All rights reserved.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions are met:
10  *
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  * 3. Neither the names of the copyright holders nor the names of its
17  *    contributors may be used to endorse or promote products derived from
18  *    this software without specific prior written permission.
19  *
20  * Alternatively, this software may be distributed under the terms of the
21  * GNU General Public License ("GPL") version 2 as published by the Free
22  * Software Foundation.
23  *
24  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
25  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
28  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
29  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
30  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
31  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
32  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
33  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
34  * POSSIBILITY OF SUCH DAMAGE.
35  */
36
37 #include "core.h"
38 #include "link.h"
39 #include "name_distr.h"
40
41 #define ITEM_SIZE sizeof(struct distr_item)
42
43 /**
44  * struct distr_item - publication info distributed to other nodes
45  * @type: name sequence type
46  * @lower: name sequence lower bound
47  * @upper: name sequence upper bound
48  * @ref: publishing port reference
49  * @key: publication key
50  *
51  * ===> All fields are stored in network byte order. <===
52  *
53  * First 3 fields identify (name or) name sequence being published.
54  * Reference field uniquely identifies port that published name sequence.
55  * Key field uniquely identifies publication, in the event a port has
56  * multiple publications of the same name sequence.
57  *
58  * Note: There is no field that identifies the publishing node because it is
59  * the same for all items contained within a publication message.
60  */
61
62 struct distr_item {
63         __be32 type;
64         __be32 lower;
65         __be32 upper;
66         __be32 ref;
67         __be32 key;
68 };
69
70 /**
71  * List of externally visible publications by this node --
72  * that is, all publications having scope > TIPC_NODE_SCOPE.
73  */
74
75 static LIST_HEAD(publ_root);
76 static u32 publ_cnt;
77
78 /**
79  * publ_to_item - add publication info to a publication message
80  */
81
82 static void publ_to_item(struct distr_item *i, struct publication *p)
83 {
84         i->type = htonl(p->type);
85         i->lower = htonl(p->lower);
86         i->upper = htonl(p->upper);
87         i->ref = htonl(p->ref);
88         i->key = htonl(p->key);
89 }
90
91 /**
92  * named_prepare_buf - allocate & initialize a publication message
93  */
94
95 static struct sk_buff *named_prepare_buf(u32 type, u32 size, u32 dest)
96 {
97         struct sk_buff *buf = tipc_buf_acquire(INT_H_SIZE + size);
98         struct tipc_msg *msg;
99
100         if (buf != NULL) {
101                 msg = buf_msg(buf);
102                 tipc_msg_init(msg, NAME_DISTRIBUTOR, type, INT_H_SIZE, dest);
103                 msg_set_size(msg, INT_H_SIZE + size);
104         }
105         return buf;
106 }
107
108 static void named_cluster_distribute(struct sk_buff *buf)
109 {
110         struct sk_buff *buf_copy;
111         struct tipc_node *n_ptr;
112
113         list_for_each_entry(n_ptr, &tipc_node_list, list) {
114                 if (tipc_node_active_links(n_ptr)) {
115                         buf_copy = skb_copy(buf, GFP_ATOMIC);
116                         if (!buf_copy)
117                                 break;
118                         msg_set_destnode(buf_msg(buf_copy), n_ptr->addr);
119                         tipc_link_send(buf_copy, n_ptr->addr, n_ptr->addr);
120                 }
121         }
122
123         buf_discard(buf);
124 }
125
126 /**
127  * tipc_named_publish - tell other nodes about a new publication by this node
128  */
129
130 void tipc_named_publish(struct publication *publ)
131 {
132         struct sk_buff *buf;
133         struct distr_item *item;
134
135         list_add_tail(&publ->local_list, &publ_root);
136         publ_cnt++;
137
138         buf = named_prepare_buf(PUBLICATION, ITEM_SIZE, 0);
139         if (!buf) {
140                 warn("Publication distribution failure\n");
141                 return;
142         }
143
144         item = (struct distr_item *)msg_data(buf_msg(buf));
145         publ_to_item(item, publ);
146         named_cluster_distribute(buf);
147 }
148
149 /**
150  * tipc_named_withdraw - tell other nodes about a withdrawn publication by this node
151  */
152
153 void tipc_named_withdraw(struct publication *publ)
154 {
155         struct sk_buff *buf;
156         struct distr_item *item;
157
158         list_del(&publ->local_list);
159         publ_cnt--;
160
161         buf = named_prepare_buf(WITHDRAWAL, ITEM_SIZE, 0);
162         if (!buf) {
163                 warn("Withdrawal distribution failure\n");
164                 return;
165         }
166
167         item = (struct distr_item *)msg_data(buf_msg(buf));
168         publ_to_item(item, publ);
169         named_cluster_distribute(buf);
170 }
171
172 /**
173  * tipc_named_node_up - tell specified node about all publications by this node
174  */
175
176 void tipc_named_node_up(unsigned long node)
177 {
178         struct publication *publ;
179         struct distr_item *item = NULL;
180         struct sk_buff *buf = NULL;
181         u32 left = 0;
182         u32 rest;
183         u32 max_item_buf;
184
185         read_lock_bh(&tipc_nametbl_lock);
186         max_item_buf = TIPC_MAX_USER_MSG_SIZE / ITEM_SIZE;
187         max_item_buf *= ITEM_SIZE;
188         rest = publ_cnt * ITEM_SIZE;
189
190         list_for_each_entry(publ, &publ_root, local_list) {
191                 if (!buf) {
192                         left = (rest <= max_item_buf) ? rest : max_item_buf;
193                         rest -= left;
194                         buf = named_prepare_buf(PUBLICATION, left, node);
195                         if (!buf) {
196                                 warn("Bulk publication distribution failure\n");
197                                 goto exit;
198                         }
199                         item = (struct distr_item *)msg_data(buf_msg(buf));
200                 }
201                 publ_to_item(item, publ);
202                 item++;
203                 left -= ITEM_SIZE;
204                 if (!left) {
205                         msg_set_link_selector(buf_msg(buf), node);
206                         tipc_link_send(buf, node, node);
207                         buf = NULL;
208                 }
209         }
210 exit:
211         read_unlock_bh(&tipc_nametbl_lock);
212 }
213
214 /**
215  * named_purge_publ - remove publication associated with a failed node
216  *
217  * Invoked for each publication issued by a newly failed node.
218  * Removes publication structure from name table & deletes it.
219  * In rare cases the link may have come back up again when this
220  * function is called, and we have two items representing the same
221  * publication. Nudge this item's key to distinguish it from the other.
222  */
223
224 static void named_purge_publ(struct publication *publ)
225 {
226         struct publication *p;
227
228         write_lock_bh(&tipc_nametbl_lock);
229         publ->key += 1222345;
230         p = tipc_nametbl_remove_publ(publ->type, publ->lower,
231                                      publ->node, publ->ref, publ->key);
232         if (p)
233                 tipc_nodesub_unsubscribe(&p->subscr);
234         write_unlock_bh(&tipc_nametbl_lock);
235
236         if (p != publ) {
237                 err("Unable to remove publication from failed node\n"
238                     "(type=%u, lower=%u, node=0x%x, ref=%u, key=%u)\n",
239                     publ->type, publ->lower, publ->node, publ->ref, publ->key);
240         }
241
242         kfree(p);
243 }
244
245 /**
246  * tipc_named_recv - process name table update message sent by another node
247  */
248
249 void tipc_named_recv(struct sk_buff *buf)
250 {
251         struct publication *publ;
252         struct tipc_msg *msg = buf_msg(buf);
253         struct distr_item *item = (struct distr_item *)msg_data(msg);
254         u32 count = msg_data_sz(msg) / ITEM_SIZE;
255
256         write_lock_bh(&tipc_nametbl_lock);
257         while (count--) {
258                 if (msg_type(msg) == PUBLICATION) {
259                         publ = tipc_nametbl_insert_publ(ntohl(item->type),
260                                                         ntohl(item->lower),
261                                                         ntohl(item->upper),
262                                                         TIPC_CLUSTER_SCOPE,
263                                                         msg_orignode(msg),
264                                                         ntohl(item->ref),
265                                                         ntohl(item->key));
266                         if (publ) {
267                                 tipc_nodesub_subscribe(&publ->subscr,
268                                                        msg_orignode(msg),
269                                                        publ,
270                                                        (net_ev_handler)
271                                                        named_purge_publ);
272                         }
273                 } else if (msg_type(msg) == WITHDRAWAL) {
274                         publ = tipc_nametbl_remove_publ(ntohl(item->type),
275                                                         ntohl(item->lower),
276                                                         msg_orignode(msg),
277                                                         ntohl(item->ref),
278                                                         ntohl(item->key));
279
280                         if (publ) {
281                                 tipc_nodesub_unsubscribe(&publ->subscr);
282                                 kfree(publ);
283                         } else {
284                                 err("Unable to remove publication by node 0x%x\n"
285                                     "(type=%u, lower=%u, ref=%u, key=%u)\n",
286                                     msg_orignode(msg),
287                                     ntohl(item->type), ntohl(item->lower),
288                                     ntohl(item->ref), ntohl(item->key));
289                         }
290                 } else {
291                         warn("Unrecognized name table message received\n");
292                 }
293                 item++;
294         }
295         write_unlock_bh(&tipc_nametbl_lock);
296         buf_discard(buf);
297 }
298
299 /**
300  * tipc_named_reinit - re-initialize local publication list
301  *
302  * This routine is called whenever TIPC networking is (re)enabled.
303  * All existing publications by this node that have "cluster" or "zone" scope
304  * are updated to reflect the node's current network address.
305  * (If the node's address is unchanged, the update loop terminates immediately.)
306  */
307
308 void tipc_named_reinit(void)
309 {
310         struct publication *publ;
311
312         write_lock_bh(&tipc_nametbl_lock);
313         list_for_each_entry(publ, &publ_root, local_list) {
314                 if (publ->node == tipc_own_addr)
315                         break;
316                 publ->node = tipc_own_addr;
317         }
318         write_unlock_bh(&tipc_nametbl_lock);
319 }