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);
119struct network tipc_net = { NULL };
120
121struct tipc_node *tipc_net_select_remote_node(u32 addr, u32 ref)
122{
123    return tipc_zone_select_remote_node(tipc_net.zones[tipc_zone(addr)], addr, ref);
124}
125
126u32 tipc_net_select_router(u32 addr, u32 ref)
127{
128    return tipc_zone_select_router(tipc_net.zones[tipc_zone(addr)], addr, ref);
129}
130
131#if 0
132u32 tipc_net_next_node(u32 a)
133{
134    if (tipc_net.zones[tipc_zone(a)])
135        return tipc_zone_next_node(a);
136    return 0;
137}
138#endif
139
140void tipc_net_remove_as_router(u32 router)
141{
142    u32 z_num;
143
144    for (z_num = 1; z_num <= tipc_max_zones; z_num++) {
145        if (!tipc_net.zones[z_num])
146            continue;
147        tipc_zone_remove_as_router(tipc_net.zones[z_num], router);
148    }
149}
150
151void tipc_net_send_external_routes(u32 dest)
152{
153    u32 z_num;
154
155    for (z_num = 1; z_num <= tipc_max_zones; z_num++) {
156        if (tipc_net.zones[z_num])
157            tipc_zone_send_external_routes(tipc_net.zones[z_num], dest);
158    }
159}
160
161static int net_init(void)
162{
163    memset(&tipc_net, 0, sizeof(tipc_net));
164    tipc_net.zones = kcalloc(tipc_max_zones + 1, sizeof(struct _zone *), GFP_ATOMIC);
165    if (!tipc_net.zones) {
166        return -ENOMEM;
167    }
168    return 0;
169}
170
171static void net_stop(void)
172{
173    u32 z_num;
174
175    if (!tipc_net.zones)
176        return;
177
178    for (z_num = 1; z_num <= tipc_max_zones; z_num++) {
179        tipc_zone_delete(tipc_net.zones[z_num]);
180    }
181    kfree(tipc_net.zones);
182    tipc_net.zones = NULL;
183}
184
185static void net_route_named_msg(struct sk_buff *buf)
186{
187    struct tipc_msg *msg = buf_msg(buf);
188    u32 dnode;
189    u32 dport;
190
191    if (!msg_named(msg)) {
192        msg_dbg(msg, "tipc_net->drop_nam:");
193        buf_discard(buf);
194        return;
195    }
196
197    dnode = addr_domain(msg_lookup_scope(msg));
198    dport = tipc_nametbl_translate(msg_nametype(msg), msg_nameinst(msg), &dnode);
199    dbg("tipc_net->lookup<%u,%u>-><%u,%x>\n",
200        msg_nametype(msg), msg_nameinst(msg), dport, dnode);
201    if (dport) {
202        msg_set_destnode(msg, dnode);
203        msg_set_destport(msg, dport);
204        tipc_net_route_msg(buf);
205        return;
206    }
207    msg_dbg(msg, "tipc_net->rej:NO NAME: ");
208    tipc_reject_msg(buf, TIPC_ERR_NO_NAME);
209}
210
211void tipc_net_route_msg(struct sk_buff *buf)
212{
213    struct tipc_msg *msg;
214    u32 dnode;
215
216    if (!buf)
217        return;
218    msg = buf_msg(buf);
219
220    msg_incr_reroute_cnt(msg);
221    if (msg_reroute_cnt(msg) > 6) {
222        if (msg_errcode(msg)) {
223            msg_dbg(msg, "NET>DISC>:");
224            buf_discard(buf);
225        } else {
226            msg_dbg(msg, "NET>REJ>:");
227            tipc_reject_msg(buf, msg_destport(msg) ?
228                    TIPC_ERR_NO_PORT : TIPC_ERR_NO_NAME);
229        }
230        return;
231    }
232
233    msg_dbg(msg, "tipc_net->rout: ");
234
235    /* Handle message for this node */
236    dnode = msg_short(msg) ? tipc_own_addr : msg_destnode(msg);
237    if (in_scope(dnode, tipc_own_addr)) {
238        if (msg_isdata(msg)) {
239            if (msg_mcast(msg))
240                tipc_port_recv_mcast(buf, NULL);
241            else if (msg_destport(msg))
242                tipc_port_recv_msg(buf);
243            else
244                net_route_named_msg(buf);
245            return;
246        }
247        switch (msg_user(msg)) {
248        case ROUTE_DISTRIBUTOR:
249            tipc_cltr_recv_routing_table(buf);
250            break;
251        case NAME_DISTRIBUTOR:
252            tipc_named_recv(buf);
253            break;
254        case CONN_MANAGER:
255            tipc_port_recv_proto_msg(buf);
256            break;
257        default:
258            msg_dbg(msg,"DROP/NET/<REC<");
259            buf_discard(buf);
260        }
261        return;
262    }
263
264    /* Handle message for another node */
265    msg_dbg(msg, "NET>SEND>: ");
266    tipc_link_send(buf, dnode, msg_link_selector(msg));
267}
268
269int tipc_net_start(u32 addr)
270{
271    char addr_string[16];
272    int res;
273
274    if (tipc_mode != TIPC_NODE_MODE)
275        return -ENOPROTOOPT;
276
277    tipc_subscr_stop();
278    tipc_cfg_stop();
279
280    tipc_own_addr = addr;
281    tipc_mode = TIPC_NET_MODE;
282    tipc_named_reinit();
283    tipc_port_reinit();
284
285    if ((res = tipc_bearer_init()) ||
286        (res = net_init()) ||
287        (res = tipc_cltr_init()) ||
288        (res = tipc_bclink_init())) {
289        return res;
290    }
291
292    tipc_k_signal((Handler)tipc_subscr_start, 0);
293    tipc_k_signal((Handler)tipc_cfg_init, 0);
294
295    info("Started in network mode\n");
296    info("Own node address %s, network identity %u\n",
297         addr_string_fill(addr_string, tipc_own_addr), tipc_net_id);
298    return 0;
299}
300
301void tipc_net_stop(void)
302{
303    if (tipc_mode != TIPC_NET_MODE)
304        return;
305    write_lock_bh(&tipc_net_lock);
306    tipc_bearer_stop();
307    tipc_mode = TIPC_NODE_MODE;
308    tipc_bclink_stop();
309    net_stop();
310    write_unlock_bh(&tipc_net_lock);
311    info("Left network mode \n");
312}
313
314

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