2 * net/tipc/net.c: TIPC network routing code
4 * Copyright (c) 1995-2006, Ericsson AB
5 * Copyright (c) 2005, Wind River Systems
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9 * modification, are permitted provided that the following conditions are met:
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18 * this software without specific prior written permission.
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.
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39 #include "name_table.h"
40 #include "name_distr.h"
47 * The TIPC locking policy is designed to ensure a very fine locking
48 * granularity, permitting complete parallel access to individual
49 * port and node/link instances. The code consists of three major
50 * locking domains, each protected with their own disjunct set of locks.
52 * 1: The routing hierarchy.
53 * Comprises the structures 'zone', 'cluster', 'node', 'link'
54 * and 'bearer'. The whole hierarchy is protected by a big
55 * read/write lock, tipc_net_lock, to enssure that nothing is added
56 * or removed while code is accessing any of these structures.
57 * This layer must not be called from the two others while they
58 * hold any of their own locks.
59 * Neither must it itself do any upcalls to the other two before
60 * it has released tipc_net_lock and other protective locks.
62 * Within the tipc_net_lock domain there are two sub-domains;'node' and
63 * 'bearer', where local write operations are permitted,
64 * provided that those are protected by individual spin_locks
65 * per instance. Code holding tipc_net_lock(read) and a node spin_lock
66 * is permitted to poke around in both the node itself and its
67 * subordinate links. I.e, it can update link counters and queues,
68 * change link state, send protocol messages, and alter the
69 * "active_links" array in the node; but it can _not_ remove a link
70 * or a node from the overall structure.
71 * Correspondingly, individual bearers may change status within a
72 * tipc_net_lock(read), protected by an individual spin_lock ber bearer
73 * instance, but it needs tipc_net_lock(write) to remove/add any bearers.
76 * 2: The transport level of the protocol.
77 * This consists of the structures port, (and its user level
78 * representations, such as user_port and tipc_sock), reference and
79 * tipc_user (port.c, reg.c, socket.c).
81 * This layer has four different locks:
82 * - The tipc_port spin_lock. This is protecting each port instance
83 * from parallel data access and removal. Since we can not place
84 * this lock in the port itself, it has been placed in the
85 * corresponding reference table entry, which has the same life
86 * cycle as the module. This entry is difficult to access from
87 * outside the TIPC core, however, so a pointer to the lock has
88 * been added in the port instance, -to be used for unlocking
90 * - A read/write lock to protect the reference table itself (teg.c).
91 * (Nobody is using read-only access to this, so it can just as
92 * well be changed to a spin_lock)
93 * - A spin lock to protect the registry of kernel/driver users (reg.c)
94 * - A global spin_lock (tipc_port_lock), which only task is to ensure
95 * consistency where more than one port is involved in an operation,
96 * i.e., whe a port is part of a linked list of ports.
97 * There are two such lists; 'port_list', which is used for management,
98 * and 'wait_list', which is used to queue ports during congestion.
100 * 3: The name table (name_table.c, name_distr.c, subscription.c)
101 * - There is one big read/write-lock (tipc_nametbl_lock) protecting the
102 * overall name table structure. Nothing must be added/removed to
103 * this structure without holding write access to it.
104 * - There is one local spin_lock per sub_sequence, which can be seen
105 * as a sub-domain to the tipc_nametbl_lock domain. It is used only
106 * for translation operations, and is needed because a translation
107 * steps the root of the 'publication' linked list between each lookup.
108 * This is always used within the scope of a tipc_nametbl_lock(read).
109 * - A local spin_lock protecting the queue of subscriber events.
112 DEFINE_RWLOCK(tipc_net_lock
);
113 struct network tipc_net
;
115 static void net_stop(void)
119 for (c_num
= 1; c_num
<= tipc_max_clusters
; c_num
++)
120 tipc_cltr_delete(tipc_net
.clusters
[c_num
]);
123 static void net_route_named_msg(struct sk_buff
*buf
)
125 struct tipc_msg
*msg
= buf_msg(buf
);
129 if (!msg_named(msg
)) {
130 msg_dbg(msg
, "tipc_net->drop_nam:");
135 dnode
= addr_domain(msg_lookup_scope(msg
));
136 dport
= tipc_nametbl_translate(msg_nametype(msg
), msg_nameinst(msg
), &dnode
);
137 dbg("tipc_net->lookup<%u,%u>-><%u,%x>\n",
138 msg_nametype(msg
), msg_nameinst(msg
), dport
, dnode
);
140 msg_set_destnode(msg
, dnode
);
141 msg_set_destport(msg
, dport
);
142 tipc_net_route_msg(buf
);
145 msg_dbg(msg
, "tipc_net->rej:NO NAME: ");
146 tipc_reject_msg(buf
, TIPC_ERR_NO_NAME
);
149 void tipc_net_route_msg(struct sk_buff
*buf
)
151 struct tipc_msg
*msg
;
158 msg_incr_reroute_cnt(msg
);
159 if (msg_reroute_cnt(msg
) > 6) {
160 if (msg_errcode(msg
)) {
161 msg_dbg(msg
, "NET>DISC>:");
164 msg_dbg(msg
, "NET>REJ>:");
165 tipc_reject_msg(buf
, msg_destport(msg
) ?
166 TIPC_ERR_NO_PORT
: TIPC_ERR_NO_NAME
);
171 msg_dbg(msg
, "tipc_net->rout: ");
173 /* Handle message for this node */
174 dnode
= msg_short(msg
) ? tipc_own_addr
: msg_destnode(msg
);
175 if (tipc_in_scope(dnode
, tipc_own_addr
)) {
176 if (msg_isdata(msg
)) {
178 tipc_port_recv_mcast(buf
, NULL
);
179 else if (msg_destport(msg
))
180 tipc_port_recv_msg(buf
);
182 net_route_named_msg(buf
);
185 switch (msg_user(msg
)) {
186 case NAME_DISTRIBUTOR
:
187 tipc_named_recv(buf
);
190 tipc_port_recv_proto_msg(buf
);
193 msg_dbg(msg
,"DROP/NET/<REC<");
199 /* Handle message for another node */
200 msg_dbg(msg
, "NET>SEND>: ");
201 skb_trim(buf
, msg_size(msg
));
202 tipc_link_send(buf
, dnode
, msg_link_selector(msg
));
205 int tipc_net_start(u32 addr
)
207 char addr_string
[16];
210 if (tipc_mode
!= TIPC_NODE_MODE
)
216 tipc_own_addr
= addr
;
217 tipc_mode
= TIPC_NET_MODE
;
221 if ((res
= tipc_cltr_init()) ||
222 (res
= tipc_bclink_init())) {
226 tipc_k_signal((Handler
)tipc_subscr_start
, 0);
227 tipc_k_signal((Handler
)tipc_cfg_init
, 0);
229 info("Started in network mode\n");
230 info("Own node address %s, network identity %u\n",
231 tipc_addr_string_fill(addr_string
, tipc_own_addr
), tipc_net_id
);
235 void tipc_net_stop(void)
237 if (tipc_mode
!= TIPC_NET_MODE
)
239 write_lock_bh(&tipc_net_lock
);
241 tipc_mode
= TIPC_NODE_MODE
;
244 write_unlock_bh(&tipc_net_lock
);
245 info("Left network mode\n");