4 * Copyright (c) 2003-2006, 2014, Ericsson AB
5 * Copyright (c) 2005-2006, 2010-2011, Wind River Systems
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41 /* min delay during bearer start up */
42 #define TIPC_LINK_REQ_INIT msecs_to_jiffies(125)
43 /* max delay if bearer has no links */
44 #define TIPC_LINK_REQ_FAST msecs_to_jiffies(1000)
45 /* max delay if bearer has links */
46 #define TIPC_LINK_REQ_SLOW msecs_to_jiffies(60000)
47 /* indicates no timer in use */
48 #define TIPC_LINK_REQ_INACTIVE 0xffffffff
52 * struct tipc_link_req - information about an ongoing link setup request
53 * @bearer_id: identity of bearer issuing requests
54 * @net: network namespace instance
55 * @dest: destination address for request messages
56 * @domain: network domain to which links can be established
57 * @num_nodes: number of nodes currently discovered (i.e. with an active link)
58 * @lock: spinlock for controlling access to requests
59 * @buf: request message to be (repeatedly) sent
60 * @timer: timer governing period between requests
61 * @timer_intv: current interval between requests (in ms)
63 struct tipc_link_req {
65 struct tipc_media_addr dest;
71 struct timer_list timer;
72 unsigned long timer_intv;
76 * tipc_disc_init_msg - initialize a link setup message
77 * @net: the applicable net namespace
78 * @type: message type (request or response)
79 * @b_ptr: ptr to bearer issuing message
81 static void tipc_disc_init_msg(struct net *net, struct sk_buff *buf, u32 type,
82 struct tipc_bearer *b_ptr)
84 struct tipc_net *tn = net_generic(net, tipc_net_id);
86 u32 dest_domain = b_ptr->domain;
89 tipc_msg_init(net, msg, LINK_CONFIG, type, INT_H_SIZE, dest_domain);
90 msg_set_non_seq(msg, 1);
91 msg_set_node_sig(msg, tn->random);
92 msg_set_dest_domain(msg, dest_domain);
93 msg_set_bc_netid(msg, tn->net_id);
94 b_ptr->media->addr2msg(msg_media_addr(msg), &b_ptr->addr);
98 * disc_dupl_alert - issue node address duplication alert
99 * @b_ptr: pointer to bearer detecting duplication
100 * @node_addr: duplicated node address
101 * @media_addr: media address advertised by duplicated node
103 static void disc_dupl_alert(struct tipc_bearer *b_ptr, u32 node_addr,
104 struct tipc_media_addr *media_addr)
106 char node_addr_str[16];
107 char media_addr_str[64];
109 tipc_addr_string_fill(node_addr_str, node_addr);
110 tipc_media_addr_printf(media_addr_str, sizeof(media_addr_str),
112 pr_warn("Duplicate %s using %s seen on <%s>\n", node_addr_str,
113 media_addr_str, b_ptr->name);
117 * tipc_disc_rcv - handle incoming discovery message (request or response)
118 * @net: the applicable net namespace
119 * @buf: buffer containing message
120 * @bearer: bearer that message arrived on
122 void tipc_disc_rcv(struct net *net, struct sk_buff *buf,
123 struct tipc_bearer *bearer)
125 struct tipc_net *tn = net_generic(net, tipc_net_id);
126 struct tipc_node *node;
127 struct tipc_link *link;
128 struct tipc_media_addr maddr;
129 struct sk_buff *rbuf;
130 struct tipc_msg *msg = buf_msg(buf);
131 u32 ddom = msg_dest_domain(msg);
132 u32 onode = msg_prevnode(msg);
133 u32 net_id = msg_bc_netid(msg);
134 u32 mtyp = msg_type(msg);
135 u32 signature = msg_node_sig(msg);
136 bool addr_match = false;
137 bool sign_match = false;
138 bool link_up = false;
139 bool accept_addr = false;
140 bool accept_sign = false;
141 bool respond = false;
143 bearer->media->msg2addr(bearer, &maddr, msg_media_addr(msg));
146 /* Ensure message from node is valid and communication is permitted */
147 if (net_id != tn->net_id)
151 if (!tipc_addr_domain_valid(ddom))
153 if (!tipc_addr_node_valid(onode))
156 if (in_own_node(net, onode)) {
157 if (memcmp(&maddr, &bearer->addr, sizeof(maddr)))
158 disc_dupl_alert(bearer, tn->own_addr, &maddr);
161 if (!tipc_in_scope(ddom, tn->own_addr))
163 if (!tipc_in_scope(bearer->domain, onode))
166 /* Locate, or if necessary, create, node: */
167 node = tipc_node_find(net, onode);
169 node = tipc_node_create(net, onode);
173 tipc_node_lock(node);
174 link = node->links[bearer->identity];
176 /* Prepare to validate requesting node's signature and media address */
177 sign_match = (signature == node->signature);
178 addr_match = link && !memcmp(&link->media_addr, &maddr, sizeof(maddr));
179 link_up = link && tipc_link_is_up(link);
182 /* These three flags give us eight permutations: */
184 if (sign_match && addr_match && link_up) {
185 /* All is fine. Do nothing. */
186 } else if (sign_match && addr_match && !link_up) {
187 /* Respond. The link will come up in due time */
189 } else if (sign_match && !addr_match && link_up) {
190 /* Peer has changed i/f address without rebooting.
191 * If so, the link will reset soon, and the next
192 * discovery will be accepted. So we can ignore it.
193 * It may also be an cloned or malicious peer having
194 * chosen the same node address and signature as an
196 * Ignore requests until the link goes down, if ever.
198 disc_dupl_alert(bearer, onode, &maddr);
199 } else if (sign_match && !addr_match && !link_up) {
200 /* Peer link has changed i/f address without rebooting.
201 * It may also be a cloned or malicious peer; we can't
202 * distinguish between the two.
203 * The signature is correct, so we must accept.
207 } else if (!sign_match && addr_match && link_up) {
208 /* Peer node rebooted. Two possibilities:
209 * - Delayed re-discovery; this link endpoint has already
210 * reset and re-established contact with the peer, before
211 * receiving a discovery message from that node.
212 * (The peer happened to receive one from this node first).
213 * - The peer came back so fast that our side has not
214 * discovered it yet. Probing from this side will soon
215 * reset the link, since there can be no working link
216 * endpoint at the peer end, and the link will re-establish.
217 * Accept the signature, since it comes from a known peer.
220 } else if (!sign_match && addr_match && !link_up) {
221 /* The peer node has rebooted.
222 * Accept signature, since it is a known peer.
226 } else if (!sign_match && !addr_match && link_up) {
227 /* Peer rebooted with new address, or a new/duplicate peer.
228 * Ignore until the link goes down, if ever.
230 disc_dupl_alert(bearer, onode, &maddr);
231 } else if (!sign_match && !addr_match && !link_up) {
232 /* Peer rebooted with new address, or it is a new peer.
233 * Accept signature and address.
241 node->signature = signature;
245 link = tipc_link_create(node, bearer, &maddr);
247 memcpy(&link->media_addr, &maddr, sizeof(maddr));
248 tipc_link_reset(link);
254 /* Send response, if necessary */
255 if (respond && (mtyp == DSC_REQ_MSG)) {
256 rbuf = tipc_buf_acquire(INT_H_SIZE);
258 tipc_disc_init_msg(net, rbuf, DSC_RESP_MSG, bearer);
259 tipc_bearer_send(net, bearer->identity, rbuf, &maddr);
263 tipc_node_unlock(node);
267 * disc_update - update frequency of periodic link setup requests
268 * @req: ptr to link request structure
270 * Reinitiates discovery process if discovery object has no associated nodes
271 * and is either not currently searching or is searching at a slow rate
273 static void disc_update(struct tipc_link_req *req)
275 if (!req->num_nodes) {
276 if ((req->timer_intv == TIPC_LINK_REQ_INACTIVE) ||
277 (req->timer_intv > TIPC_LINK_REQ_FAST)) {
278 req->timer_intv = TIPC_LINK_REQ_INIT;
279 mod_timer(&req->timer, jiffies + req->timer_intv);
285 * tipc_disc_add_dest - increment set of discovered nodes
286 * @req: ptr to link request structure
288 void tipc_disc_add_dest(struct tipc_link_req *req)
290 spin_lock_bh(&req->lock);
292 spin_unlock_bh(&req->lock);
296 * tipc_disc_remove_dest - decrement set of discovered nodes
297 * @req: ptr to link request structure
299 void tipc_disc_remove_dest(struct tipc_link_req *req)
301 spin_lock_bh(&req->lock);
304 spin_unlock_bh(&req->lock);
308 * disc_timeout - send a periodic link setup request
309 * @data: ptr to link request structure
311 * Called whenever a link setup request timer associated with a bearer expires.
313 static void disc_timeout(unsigned long data)
315 struct tipc_link_req *req = (struct tipc_link_req *)data;
318 spin_lock_bh(&req->lock);
320 /* Stop searching if only desired node has been found */
321 if (tipc_node(req->domain) && req->num_nodes) {
322 req->timer_intv = TIPC_LINK_REQ_INACTIVE;
327 * Send discovery message, then update discovery timer
329 * Keep doubling time between requests until limit is reached;
330 * hold at fast polling rate if don't have any associated nodes,
331 * otherwise hold at slow polling rate
333 tipc_bearer_send(req->net, req->bearer_id, req->buf, &req->dest);
336 req->timer_intv *= 2;
338 max_delay = TIPC_LINK_REQ_SLOW;
340 max_delay = TIPC_LINK_REQ_FAST;
341 if (req->timer_intv > max_delay)
342 req->timer_intv = max_delay;
344 mod_timer(&req->timer, jiffies + req->timer_intv);
346 spin_unlock_bh(&req->lock);
350 * tipc_disc_create - create object to send periodic link setup requests
351 * @net: the applicable net namespace
352 * @b_ptr: ptr to bearer issuing requests
353 * @dest: destination address for request messages
354 * @dest_domain: network domain to which links can be established
356 * Returns 0 if successful, otherwise -errno.
358 int tipc_disc_create(struct net *net, struct tipc_bearer *b_ptr,
359 struct tipc_media_addr *dest)
361 struct tipc_link_req *req;
363 req = kmalloc(sizeof(*req), GFP_ATOMIC);
367 req->buf = tipc_buf_acquire(INT_H_SIZE);
373 tipc_disc_init_msg(net, req->buf, DSC_REQ_MSG, b_ptr);
374 memcpy(&req->dest, dest, sizeof(*dest));
376 req->bearer_id = b_ptr->identity;
377 req->domain = b_ptr->domain;
379 req->timer_intv = TIPC_LINK_REQ_INIT;
380 spin_lock_init(&req->lock);
381 setup_timer(&req->timer, disc_timeout, (unsigned long)req);
382 mod_timer(&req->timer, jiffies + req->timer_intv);
383 b_ptr->link_req = req;
384 tipc_bearer_send(net, req->bearer_id, req->buf, &req->dest);
389 * tipc_disc_delete - destroy object sending periodic link setup requests
390 * @req: ptr to link request structure
392 void tipc_disc_delete(struct tipc_link_req *req)
394 del_timer_sync(&req->timer);
400 * tipc_disc_reset - reset object to send periodic link setup requests
401 * @net: the applicable net namespace
402 * @b_ptr: ptr to bearer issuing requests
403 * @dest_domain: network domain to which links can be established
405 void tipc_disc_reset(struct net *net, struct tipc_bearer *b_ptr)
407 struct tipc_link_req *req = b_ptr->link_req;
409 spin_lock_bh(&req->lock);
410 tipc_disc_init_msg(net, req->buf, DSC_REQ_MSG, b_ptr);
412 req->bearer_id = b_ptr->identity;
413 req->domain = b_ptr->domain;
415 req->timer_intv = TIPC_LINK_REQ_INIT;
416 mod_timer(&req->timer, jiffies + req->timer_intv);
417 tipc_bearer_send(net, req->bearer_id, req->buf, &req->dest);
418 spin_unlock_bh(&req->lock);