1 files changed, 402 insertions, 0 deletions
diff --git a/net/tipc/discover.c b/net/tipc/discover.c
new file mode 100644
index 00000000..c630a21b
--- /dev/null
+++ b/net/tipc/discover.c
@@ -0,0 +1,402 @@
+/*
+ * net/tipc/discover.c
+ *
+ * Copyright (c) 2003-2006, Ericsson AB
+ * Copyright (c) 2005-2006, 2010-2011, Wind River Systems
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the names of the copyright holders nor the names of its
+ *    contributors may be used to endorse or promote products derived from
+ *    this software without specific prior written permission.
+ *
+ * Alternatively, this software may be distributed under the terms of the
+ * GNU General Public License ("GPL") version 2 as published by the Free
+ * Software Foundation.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "core.h"
+#include "link.h"
+#include "discover.h"
+
+#define TIPC_LINK_REQ_INIT	125	/* min delay during bearer start up */
+#define TIPC_LINK_REQ_FAST	1000	/* max delay if bearer has no links */
+#define TIPC_LINK_REQ_SLOW	60000	/* max delay if bearer has links */
+#define TIPC_LINK_REQ_INACTIVE	0xffffffff /* indicates no timer in use */
+
+
+/**
+ * struct tipc_link_req - information about an ongoing link setup request
+ * @bearer: bearer issuing requests
+ * @dest: destination address for request messages
+ * @domain: network domain to which links can be established
+ * @num_nodes: number of nodes currently discovered (i.e. with an active link)
+ * @buf: request message to be (repeatedly) sent
+ * @timer: timer governing period between requests
+ * @timer_intv: current interval between requests (in ms)
+ */
+struct tipc_link_req {
+	struct tipc_bearer *bearer;
+	struct tipc_media_addr dest;
+	u32 domain;
+	int num_nodes;
+	struct sk_buff *buf;
+	struct timer_list timer;
+	unsigned int timer_intv;
+};
+
+/**
+ * tipc_disc_init_msg - initialize a link setup message
+ * @type: message type (request or response)
+ * @dest_domain: network domain of node(s) which should respond to message
+ * @b_ptr: ptr to bearer issuing message
+ */
+
+static struct sk_buff *tipc_disc_init_msg(u32 type,
+					  u32 dest_domain,
+					  struct tipc_bearer *b_ptr)
+{
+	struct sk_buff *buf = tipc_buf_acquire(INT_H_SIZE);
+	struct tipc_msg *msg;
+
+	if (buf) {
+		msg = buf_msg(buf);
+		tipc_msg_init(msg, LINK_CONFIG, type, INT_H_SIZE, dest_domain);
+		msg_set_non_seq(msg, 1);
+		msg_set_node_sig(msg, tipc_random);
+		msg_set_dest_domain(msg, dest_domain);
+		msg_set_bc_netid(msg, tipc_net_id);
+		b_ptr->media->addr2msg(&b_ptr->addr, msg_media_addr(msg));
+	}
+	return buf;
+}
+
+/**
+ * disc_dupl_alert - issue node address duplication alert
+ * @b_ptr: pointer to bearer detecting duplication
+ * @node_addr: duplicated node address
+ * @media_addr: media address advertised by duplicated node
+ */
+
+static void disc_dupl_alert(struct tipc_bearer *b_ptr, u32 node_addr,
+			    struct tipc_media_addr *media_addr)
+{
+	char node_addr_str[16];
+	char media_addr_str[64];
+	struct print_buf pb;
+
+	tipc_addr_string_fill(node_addr_str, node_addr);
+	tipc_printbuf_init(&pb, media_addr_str, sizeof(media_addr_str));
+	tipc_media_addr_printf(&pb, media_addr);
+	tipc_printbuf_validate(&pb);
+	warn("Duplicate %s using %s seen on <%s>\n",
+	     node_addr_str, media_addr_str, b_ptr->name);
+}
+
+/**
+ * tipc_disc_recv_msg - handle incoming link setup message (request or response)
+ * @buf: buffer containing message
+ * @b_ptr: bearer that message arrived on
+ */
+
+void tipc_disc_recv_msg(struct sk_buff *buf, struct tipc_bearer *b_ptr)
+{
+	struct tipc_node *n_ptr;
+	struct tipc_link *link;
+	struct tipc_media_addr media_addr;
+	struct sk_buff *rbuf;
+	struct tipc_msg *msg = buf_msg(buf);
+	u32 dest = msg_dest_domain(msg);
+	u32 orig = msg_prevnode(msg);
+	u32 net_id = msg_bc_netid(msg);
+	u32 type = msg_type(msg);
+	u32 signature = msg_node_sig(msg);
+	int addr_mismatch;
+	int link_fully_up;
+
+	media_addr.broadcast = 1;
+	b_ptr->media->msg2addr(&media_addr, msg_media_addr(msg));
+	kfree_skb(buf);
+
+	/* Ensure message from node is valid and communication is permitted */
+	if (net_id != tipc_net_id)
+		return;
+	if (media_addr.broadcast)
+		return;
+	if (!tipc_addr_domain_valid(dest))
+		return;
+	if (!tipc_addr_node_valid(orig))
+		return;
+	if (orig == tipc_own_addr) {
+		if (memcmp(&media_addr, &b_ptr->addr, sizeof(media_addr)))
+			disc_dupl_alert(b_ptr, tipc_own_addr, &media_addr);
+		return;
+	}
+	if (!tipc_in_scope(dest, tipc_own_addr))
+		return;
+	if (!tipc_in_scope(b_ptr->link_req->domain, orig))
+		return;
+
+	/* Locate structure corresponding to requesting node */
+	n_ptr = tipc_node_find(orig);
+	if (!n_ptr) {
+		n_ptr = tipc_node_create(orig);
+		if (!n_ptr)
+			return;
+	}
+	tipc_node_lock(n_ptr);
+
+	/* Prepare to validate requesting node's signature and media address */
+	link = n_ptr->links[b_ptr->identity];
+	addr_mismatch = (link != NULL) &&
+		memcmp(&link->media_addr, &media_addr, sizeof(media_addr));
+
+	/*
+	 * Ensure discovery message's signature is correct
+	 *
+	 * If signature is incorrect and there is no working link to the node,
+	 * accept the new signature but invalidate all existing links to the
+	 * node so they won't re-activate without a new discovery message.
+	 *
+	 * If signature is incorrect and the requested link to the node is
+	 * working, accept the new signature. (This is an instance of delayed
+	 * rediscovery, where a link endpoint was able to re-establish contact
+	 * with its peer endpoint on a node that rebooted before receiving a
+	 * discovery message from that node.)
+	 *
+	 * If signature is incorrect and there is a working link to the node
+	 * that is not the requested link, reject the request (must be from
+	 * a duplicate node).
+	 */
+	if (signature != n_ptr->signature) {
+		if (n_ptr->working_links == 0) {
+			struct tipc_link *curr_link;
+			int i;
+
+			for (i = 0; i < MAX_BEARERS; i++) {
+				curr_link = n_ptr->links[i];
+				if (curr_link) {
+					memset(&curr_link->media_addr, 0,
+					       sizeof(media_addr));
+					tipc_link_reset(curr_link);
+				}
+			}
+			addr_mismatch = (link != NULL);
+		} else if (tipc_link_is_up(link) && !addr_mismatch) {
+			/* delayed rediscovery */
+		} else {
+			disc_dupl_alert(b_ptr, orig, &media_addr);
+			tipc_node_unlock(n_ptr);
+			return;
+		}
+		n_ptr->signature = signature;
+	}
+
+	/*
+	 * Ensure requesting node's media address is correct
+	 *
+	 * If media address doesn't match and the link is working, reject the
+	 * request (must be from a duplicate node).
+	 *
+	 * If media address doesn't match and the link is not working, accept
+	 * the new media address and reset the link to ensure it starts up
+	 * cleanly.
+	 */
+
+	if (addr_mismatch) {
+		if (tipc_link_is_up(link)) {
+			disc_dupl_alert(b_ptr, orig, &media_addr);
+			tipc_node_unlock(n_ptr);
+			return;
+		} else {
+			memcpy(&link->media_addr, &media_addr,
+			       sizeof(media_addr));
+			tipc_link_reset(link);
+		}
+	}
+
+	/* Create a link endpoint for this bearer, if necessary */
+	if (!link) {
+		link = tipc_link_create(n_ptr, b_ptr, &media_addr);
+		if (!link) {
+			tipc_node_unlock(n_ptr);
+			return;
+		}
+	}
+
+	/* Accept discovery message & send response, if necessary */
+	link_fully_up = link_working_working(link);
+
+	if ((type == DSC_REQ_MSG) && !link_fully_up && !b_ptr->blocked) {
+		rbuf = tipc_disc_init_msg(DSC_RESP_MSG, orig, b_ptr);
+		if (rbuf) {
+			b_ptr->media->send_msg(rbuf, b_ptr, &media_addr);
+			kfree_skb(rbuf);
+		}
+	}
+
+	tipc_node_unlock(n_ptr);
+}
+
+/**
+ * disc_update - update frequency of periodic link setup requests
+ * @req: ptr to link request structure
+ *
+ * Reinitiates discovery process if discovery object has no associated nodes
+ * and is either not currently searching or is searching at a slow rate
+ */
+
+static void disc_update(struct tipc_link_req *req)
+{
+	if (!req->num_nodes) {
+		if ((req->timer_intv == TIPC_LINK_REQ_INACTIVE) ||
+		    (req->timer_intv > TIPC_LINK_REQ_FAST)) {
+			req->timer_intv = TIPC_LINK_REQ_INIT;
+			k_start_timer(&req->timer, req->timer_intv);
+		}
+	}
+}
+
+/**
+ * tipc_disc_add_dest - increment set of discovered nodes
+ * @req: ptr to link request structure
+ */
+
+void tipc_disc_add_dest(struct tipc_link_req *req)
+{
+	req->num_nodes++;
+}
+
+/**
+ * tipc_disc_remove_dest - decrement set of discovered nodes
+ * @req: ptr to link request structure
+ */
+
+void tipc_disc_remove_dest(struct tipc_link_req *req)
+{
+	req->num_nodes--;
+	disc_update(req);
+}
+
+/**
+ * disc_send_msg - send link setup request message
+ * @req: ptr to link request structure
+ */
+
+static void disc_send_msg(struct tipc_link_req *req)
+{
+	if (!req->bearer->blocked)
+		tipc_bearer_send(req->bearer, req->buf, &req->dest);
+}
+
+/**
+ * disc_timeout - send a periodic link setup request
+ * @req: ptr to link request structure
+ *
+ * Called whenever a link setup request timer associated with a bearer expires.
+ */
+
+static void disc_timeout(struct tipc_link_req *req)
+{
+	int max_delay;
+
+	spin_lock_bh(&req->bearer->lock);
+
+	/* Stop searching if only desired node has been found */
+
+	if (tipc_node(req->domain) && req->num_nodes) {
+		req->timer_intv = TIPC_LINK_REQ_INACTIVE;
+		goto exit;
+	}
+
+	/*
+	 * Send discovery message, then update discovery timer
+	 *
+	 * Keep doubling time between requests until limit is reached;
+	 * hold at fast polling rate if don't have any associated nodes,
+	 * otherwise hold at slow polling rate
+	 */
+
+	disc_send_msg(req);
+
+	req->timer_intv *= 2;
+	if (req->num_nodes)
+		max_delay = TIPC_LINK_REQ_SLOW;
+	else
+		max_delay = TIPC_LINK_REQ_FAST;
+	if (req->timer_intv > max_delay)
+		req->timer_intv = max_delay;
+
+	k_start_timer(&req->timer, req->timer_intv);
+exit:
+	spin_unlock_bh(&req->bearer->lock);
+}
+
+/**
+ * tipc_disc_create - create object to send periodic link setup requests
+ * @b_ptr: ptr to bearer issuing requests
+ * @dest: destination address for request messages
+ * @dest_domain: network domain to which links can be established
+ *
+ * Returns 0 if successful, otherwise -errno.
+ */
+
+int tipc_disc_create(struct tipc_bearer *b_ptr,
+		     struct tipc_media_addr *dest, u32 dest_domain)
+{
+	struct tipc_link_req *req;
+
+	req = kmalloc(sizeof(*req), GFP_ATOMIC);
+	if (!req)
+		return -ENOMEM;
+
+	req->buf = tipc_disc_init_msg(DSC_REQ_MSG, dest_domain, b_ptr);
+	if (!req->buf) {
+		kfree(req);
+		return -ENOMSG;
+	}
+
+	memcpy(&req->dest, dest, sizeof(*dest));
+	req->bearer = b_ptr;
+	req->domain = dest_domain;
+	req->num_nodes = 0;
+	req->timer_intv = TIPC_LINK_REQ_INIT;
+	k_init_timer(&req->timer, (Handler)disc_timeout, (unsigned long)req);
+	k_start_timer(&req->timer, req->timer_intv);
+	b_ptr->link_req = req;
+	disc_send_msg(req);
+	return 0;
+}
+
+/**
+ * tipc_disc_delete - destroy object sending periodic link setup requests
+ * @req: ptr to link request structure
+ */
+
+void tipc_disc_delete(struct tipc_link_req *req)
+{
+	k_cancel_timer(&req->timer);
+	k_term_timer(&req->timer);
+	kfree_skb(req->buf);
+	kfree(req);
+}
+