Root/net/tipc/net.c

1/*
2 * net/tipc/net.c: TIPC network routing code
3 *
4 * Copyright (c) 1995-2006, Ericsson AB
5 * Copyright (c) 2005, 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 "bearer.h"
39#include "net.h"
40#include "zone.h"
41#include "addr.h"
42#include "name_table.h"
43#include "name_distr.h"
44#include "subscr.h"
45#include "link.h"
46#include "msg.h"
47#include "port.h"
48#include "bcast.h"
49#include "discover.h"
50#include "config.h"
51
52/*
53 * The TIPC locking policy is designed to ensure a very fine locking
54 * granularity, permitting complete parallel access to individual
55 * port and node/link instances. The code consists of three major
56 * locking domains, each protected with their own disjunct set of locks.
57 *
58 * 1: The routing hierarchy.
59 * Comprises the structures 'zone', 'cluster', 'node', 'link'
60 * and 'bearer'. The whole hierarchy is protected by a big
61 * read/write lock, tipc_net_lock, to enssure that nothing is added
62 * or removed while code is accessing any of these structures.
63 * This layer must not be called from the two others while they
64 * hold any of their own locks.
65 * Neither must it itself do any upcalls to the other two before
66 * it has released tipc_net_lock and other protective locks.
67 *
68 * Within the tipc_net_lock domain there are two sub-domains;'node' and
69 * 'bearer', where local write operations are permitted,
70 * provided that those are protected by individual spin_locks
71 * per instance. Code holding tipc_net_lock(read) and a node spin_lock
72 * is permitted to poke around in both the node itself and its
73 * subordinate links. I.e, it can update link counters and queues,
74 * change link state, send protocol messages, and alter the
75 * "active_links" array in the node; but it can _not_ remove a link
76 * or a node from the overall structure.
77 * Correspondingly, individual bearers may change status within a
78 * tipc_net_lock(read), protected by an individual spin_lock ber bearer
79 * instance, but it needs tipc_net_lock(write) to remove/add any bearers.
80 *
81 *
82 * 2: The transport level of the protocol.
83 * This consists of the structures port, (and its user level
84 * representations, such as user_port and tipc_sock), reference and
85 * tipc_user (port.c, reg.c, socket.c).
86 *
87 * This layer has four different locks:
88 * - The tipc_port spin_lock. This is protecting each port instance
89 * from parallel data access and removal. Since we can not place
90 * this lock in the port itself, it has been placed in the
91 * corresponding reference table entry, which has the same life
92 * cycle as the module. This entry is difficult to access from
93 * outside the TIPC core, however, so a pointer to the lock has
94 * been added in the port instance, -to be used for unlocking
95 * only.
96 * - A read/write lock to protect the reference table itself (teg.c).
97 * (Nobody is using read-only access to this, so it can just as
98 * well be changed to a spin_lock)
99 * - A spin lock to protect the registry of kernel/driver users (reg.c)
100 * - A global spin_lock (tipc_port_lock), which only task is to ensure
101 * consistency where more than one port is involved in an operation,
102 * i.e., whe a port is part of a linked list of ports.
103 * There are two such lists; 'port_list', which is used for management,
104 * and 'wait_list', which is used to queue ports during congestion.
105 *
106 * 3: The name table (name_table.c, name_distr.c, subscription.c)
107 * - There is one big read/write-lock (tipc_nametbl_lock) protecting the
108 * overall name table structure. Nothing must be added/removed to
109 * this structure without holding write access to it.
110 * - There is one local spin_lock per sub_sequence, which can be seen
111 * as a sub-domain to the tipc_nametbl_lock domain. It is used only
112 * for translation operations, and is needed because a translation
113 * steps the root of the 'publication' linked list between each lookup.
114 * This is always used within the scope of a tipc_nametbl_lock(read).
115 * - A local spin_lock protecting the queue of subscriber events.
116*/
117
118DEFINE_RWLOCK(tipc_net_lock);
119static struct _zone *tipc_zones[256] = { NULL, };
120struct network tipc_net = { tipc_zones };
121
122struct tipc_node *tipc_net_select_remote_node(u32 addr, u32 ref)
123{
124    return tipc_zone_select_remote_node(tipc_net.zones[tipc_zone(addr)], addr, ref);
125}
126
127u32 tipc_net_select_router(u32 addr, u32 ref)
128{
129    return tipc_zone_select_router(tipc_net.zones[tipc_zone(addr)], addr, ref);
130}
131
132#if 0
133u32 tipc_net_next_node(u32 a)
134{
135    if (tipc_net.zones[tipc_zone(a)])
136        return tipc_zone_next_node(a);
137    return 0;
138}
139#endif
140
141void tipc_net_remove_as_router(u32 router)
142{
143    u32 z_num;
144
145    for (z_num = 1; z_num <= tipc_max_zones; z_num++) {
146        if (!tipc_net.zones[z_num])
147            continue;
148        tipc_zone_remove_as_router(tipc_net.zones[z_num], router);
149    }
150}
151
152void tipc_net_send_external_routes(u32 dest)
153{
154    u32 z_num;
155
156    for (z_num = 1; z_num <= tipc_max_zones; z_num++) {
157        if (tipc_net.zones[z_num])
158            tipc_zone_send_external_routes(tipc_net.zones[z_num], dest);
159    }
160}
161
162static void net_stop(void)
163{
164    u32 z_num;
165
166    for (z_num = 1; z_num <= tipc_max_zones; z_num++)
167        tipc_zone_delete(tipc_net.zones[z_num]);
168}
169
170static void net_route_named_msg(struct sk_buff *buf)
171{
172    struct tipc_msg *msg = buf_msg(buf);
173    u32 dnode;
174    u32 dport;
175
176    if (!msg_named(msg)) {
177        msg_dbg(msg, "tipc_net->drop_nam:");
178        buf_discard(buf);
179        return;
180    }
181
182    dnode = addr_domain(msg_lookup_scope(msg));
183    dport = tipc_nametbl_translate(msg_nametype(msg), msg_nameinst(msg), &dnode);
184    dbg("tipc_net->lookup<%u,%u>-><%u,%x>\n",
185        msg_nametype(msg), msg_nameinst(msg), dport, dnode);
186    if (dport) {
187        msg_set_destnode(msg, dnode);
188        msg_set_destport(msg, dport);
189        tipc_net_route_msg(buf);
190        return;
191    }
192    msg_dbg(msg, "tipc_net->rej:NO NAME: ");
193    tipc_reject_msg(buf, TIPC_ERR_NO_NAME);
194}
195
196void tipc_net_route_msg(struct sk_buff *buf)
197{
198    struct tipc_msg *msg;
199    u32 dnode;
200
201    if (!buf)
202        return;
203    msg = buf_msg(buf);
204
205    msg_incr_reroute_cnt(msg);
206    if (msg_reroute_cnt(msg) > 6) {
207        if (msg_errcode(msg)) {
208            msg_dbg(msg, "NET>DISC>:");
209            buf_discard(buf);
210        } else {
211            msg_dbg(msg, "NET>REJ>:");
212            tipc_reject_msg(buf, msg_destport(msg) ?
213                    TIPC_ERR_NO_PORT : TIPC_ERR_NO_NAME);
214        }
215        return;
216    }
217
218    msg_dbg(msg, "tipc_net->rout: ");
219
220    /* Handle message for this node */
221    dnode = msg_short(msg) ? tipc_own_addr : msg_destnode(msg);
222    if (tipc_in_scope(dnode, tipc_own_addr)) {
223        if (msg_isdata(msg)) {
224            if (msg_mcast(msg))
225                tipc_port_recv_mcast(buf, NULL);
226            else if (msg_destport(msg))
227                tipc_port_recv_msg(buf);
228            else
229                net_route_named_msg(buf);
230            return;
231        }
232        switch (msg_user(msg)) {
233        case ROUTE_DISTRIBUTOR:
234            tipc_cltr_recv_routing_table(buf);
235            break;
236        case NAME_DISTRIBUTOR:
237            tipc_named_recv(buf);
238            break;
239        case CONN_MANAGER:
240            tipc_port_recv_proto_msg(buf);
241            break;
242        default:
243            msg_dbg(msg,"DROP/NET/<REC<");
244            buf_discard(buf);
245        }
246        return;
247    }
248
249    /* Handle message for another node */
250    msg_dbg(msg, "NET>SEND>: ");
251    tipc_link_send(buf, dnode, msg_link_selector(msg));
252}
253
254int tipc_net_start(u32 addr)
255{
256    char addr_string[16];
257    int res;
258
259    if (tipc_mode != TIPC_NODE_MODE)
260        return -ENOPROTOOPT;
261
262    tipc_subscr_stop();
263    tipc_cfg_stop();
264
265    tipc_own_addr = addr;
266    tipc_mode = TIPC_NET_MODE;
267    tipc_named_reinit();
268    tipc_port_reinit();
269
270    if ((res = tipc_cltr_init()) ||
271        (res = tipc_bclink_init())) {
272        return res;
273    }
274
275    tipc_k_signal((Handler)tipc_subscr_start, 0);
276    tipc_k_signal((Handler)tipc_cfg_init, 0);
277
278    info("Started in network mode\n");
279    info("Own node address %s, network identity %u\n",
280         tipc_addr_string_fill(addr_string, tipc_own_addr), tipc_net_id);
281    return 0;
282}
283
284void tipc_net_stop(void)
285{
286    if (tipc_mode != TIPC_NET_MODE)
287        return;
288    write_lock_bh(&tipc_net_lock);
289    tipc_bearer_stop();
290    tipc_mode = TIPC_NODE_MODE;
291    tipc_bclink_stop();
292    net_stop();
293    write_unlock_bh(&tipc_net_lock);
294    info("Left network mode\n");
295}
296
297

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