--- /dev/null
+/*
+ * net/tipc/discover.c
+ *
+ * Copyright (c) 2003-2006, 2014-2015, 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"
+
+/* min delay during bearer start up */
+#define TIPC_LINK_REQ_INIT msecs_to_jiffies(125)
+/* max delay if bearer has no links */
+#define TIPC_LINK_REQ_FAST msecs_to_jiffies(1000)
+/* max delay if bearer has links */
+#define TIPC_LINK_REQ_SLOW msecs_to_jiffies(60000)
+/* indicates no timer in use */
+#define TIPC_LINK_REQ_INACTIVE 0xffffffff
+
+/**
+ * struct tipc_link_req - information about an ongoing link setup request
+ * @bearer_id: identity of bearer issuing requests
+ * @net: network namespace instance
+ * @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)
+ * @lock: spinlock for controlling access to requests
+ * @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 {
+ u32 bearer_id;
+ struct tipc_media_addr dest;
+ struct net *net;
+ u32 domain;
+ int num_nodes;
+ spinlock_t lock;
+ struct sk_buff *buf;
+ struct timer_list timer;
+ unsigned long timer_intv;
+};
+
+/**
+ * tipc_disc_init_msg - initialize a link setup message
+ * @net: the applicable net namespace
+ * @type: message type (request or response)
+ * @b_ptr: ptr to bearer issuing message
+ */
+static void tipc_disc_init_msg(struct net *net, struct sk_buff *buf, u32 type,
+ struct tipc_bearer *b_ptr)
+{
+ struct tipc_net *tn = net_generic(net, tipc_net_id);
+ struct tipc_msg *msg;
+ u32 dest_domain = b_ptr->domain;
+
+ msg = buf_msg(buf);
+ tipc_msg_init(tn->own_addr, msg, LINK_CONFIG, type,
+ MAX_H_SIZE, dest_domain);
+ msg_set_non_seq(msg, 1);
+ msg_set_node_sig(msg, tn->random);
+ msg_set_node_capabilities(msg, 0);
+ msg_set_dest_domain(msg, dest_domain);
+ msg_set_bc_netid(msg, tn->net_id);
+ b_ptr->media->addr2msg(msg_media_addr(msg), &b_ptr->addr);
+}
+
+/**
+ * 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];
+
+ tipc_addr_string_fill(node_addr_str, node_addr);
+ tipc_media_addr_printf(media_addr_str, sizeof(media_addr_str),
+ media_addr);
+ pr_warn("Duplicate %s using %s seen on <%s>\n", node_addr_str,
+ media_addr_str, b_ptr->name);
+}
+
+/**
+ * tipc_disc_rcv - handle incoming discovery message (request or response)
+ * @net: the applicable net namespace
+ * @buf: buffer containing message
+ * @bearer: bearer that message arrived on
+ */
+void tipc_disc_rcv(struct net *net, struct sk_buff *buf,
+ struct tipc_bearer *bearer)
+{
+ struct tipc_net *tn = net_generic(net, tipc_net_id);
+ struct tipc_node *node;
+ struct tipc_link *link;
+ struct tipc_media_addr maddr;
+ struct sk_buff *rbuf;
+ struct tipc_msg *msg = buf_msg(buf);
+ u32 ddom = msg_dest_domain(msg);
+ u32 onode = msg_prevnode(msg);
+ u32 net_id = msg_bc_netid(msg);
+ u32 mtyp = msg_type(msg);
+ u32 signature = msg_node_sig(msg);
+ u16 caps = msg_node_capabilities(msg);
+ bool addr_match = false;
+ bool sign_match = false;
+ bool link_up = false;
+ bool accept_addr = false;
+ bool accept_sign = false;
+ bool respond = false;
+
+ bearer->media->msg2addr(bearer, &maddr, msg_media_addr(msg));
+ kfree_skb(buf);
+
+ /* Ensure message from node is valid and communication is permitted */
+ if (net_id != tn->net_id)
+ return;
+ if (maddr.broadcast)
+ return;
+ if (!tipc_addr_domain_valid(ddom))
+ return;
+ if (!tipc_addr_node_valid(onode))
+ return;
+
+ if (in_own_node(net, onode)) {
+ if (memcmp(&maddr, &bearer->addr, sizeof(maddr)))
+ disc_dupl_alert(bearer, tn->own_addr, &maddr);
+ return;
+ }
+ if (!tipc_in_scope(ddom, tn->own_addr))
+ return;
+ if (!tipc_in_scope(bearer->domain, onode))
+ return;
+
+ node = tipc_node_create(net, onode);
+ if (!node)
+ return;
+ tipc_node_lock(node);
+ node->capabilities = caps;
+ link = node->links[bearer->identity];
+
+ /* Prepare to validate requesting node's signature and media address */
+ sign_match = (signature == node->signature);
+ addr_match = link && !memcmp(&link->media_addr, &maddr, sizeof(maddr));
+ link_up = link && tipc_link_is_up(link);
+
+
+ /* These three flags give us eight permutations: */
+
+ if (sign_match && addr_match && link_up) {
+ /* All is fine. Do nothing. */
+ } else if (sign_match && addr_match && !link_up) {
+ /* Respond. The link will come up in due time */
+ respond = true;
+ } else if (sign_match && !addr_match && link_up) {
+ /* Peer has changed i/f address without rebooting.
+ * If so, the link will reset soon, and the next
+ * discovery will be accepted. So we can ignore it.
+ * It may also be an cloned or malicious peer having
+ * chosen the same node address and signature as an
+ * existing one.
+ * Ignore requests until the link goes down, if ever.
+ */
+ disc_dupl_alert(bearer, onode, &maddr);
+ } else if (sign_match && !addr_match && !link_up) {
+ /* Peer link has changed i/f address without rebooting.
+ * It may also be a cloned or malicious peer; we can't
+ * distinguish between the two.
+ * The signature is correct, so we must accept.
+ */
+ accept_addr = true;
+ respond = true;
+ } else if (!sign_match && addr_match && link_up) {
+ /* Peer node rebooted. Two possibilities:
+ * - Delayed re-discovery; this link endpoint has already
+ * reset and re-established contact with the peer, before
+ * receiving a discovery message from that node.
+ * (The peer happened to receive one from this node first).
+ * - The peer came back so fast that our side has not
+ * discovered it yet. Probing from this side will soon
+ * reset the link, since there can be no working link
+ * endpoint at the peer end, and the link will re-establish.
+ * Accept the signature, since it comes from a known peer.
+ */
+ accept_sign = true;
+ } else if (!sign_match && addr_match && !link_up) {
+ /* The peer node has rebooted.
+ * Accept signature, since it is a known peer.
+ */
+ accept_sign = true;
+ respond = true;
+ } else if (!sign_match && !addr_match && link_up) {
+ /* Peer rebooted with new address, or a new/duplicate peer.
+ * Ignore until the link goes down, if ever.
+ */
+ disc_dupl_alert(bearer, onode, &maddr);
+ } else if (!sign_match && !addr_match && !link_up) {
+ /* Peer rebooted with new address, or it is a new peer.
+ * Accept signature and address.
+ */
+ accept_sign = true;
+ accept_addr = true;
+ respond = true;
+ }
+
+ if (accept_sign)
+ node->signature = signature;
+
+ if (accept_addr) {
+ if (!link)
+ link = tipc_link_create(node, bearer, &maddr);
+ if (link) {
+ memcpy(&link->media_addr, &maddr, sizeof(maddr));
+ tipc_link_reset(link);
+ } else {
+ respond = false;
+ }
+ }
+
+ /* Send response, if necessary */
+ if (respond && (mtyp == DSC_REQ_MSG)) {
+ rbuf = tipc_buf_acquire(MAX_H_SIZE);
+ if (rbuf) {
+ tipc_disc_init_msg(net, rbuf, DSC_RESP_MSG, bearer);
+ tipc_bearer_send(net, bearer->identity, rbuf, &maddr);
+ kfree_skb(rbuf);
+ }
+ }
+ tipc_node_unlock(node);
+ tipc_node_put(node);
+}
+
+/**
+ * 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;
+ mod_timer(&req->timer, jiffies + 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)
+{
+ spin_lock_bh(&req->lock);
+ req->num_nodes++;
+ spin_unlock_bh(&req->lock);
+}
+
+/**
+ * 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)
+{
+ spin_lock_bh(&req->lock);
+ req->num_nodes--;
+ disc_update(req);
+ spin_unlock_bh(&req->lock);
+}
+
+/**
+ * disc_timeout - send a periodic link setup request
+ * @data: ptr to link request structure
+ *
+ * Called whenever a link setup request timer associated with a bearer expires.
+ */
+static void disc_timeout(unsigned long data)
+{
+ struct tipc_link_req *req = (struct tipc_link_req *)data;
+ int max_delay;
+
+ spin_lock_bh(&req->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
+ */
+ tipc_bearer_send(req->net, req->bearer_id, req->buf, &req->dest);
+
+
+ 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;
+
+ mod_timer(&req->timer, jiffies + req->timer_intv);
+exit:
+ spin_unlock_bh(&req->lock);
+}
+
+/**
+ * tipc_disc_create - create object to send periodic link setup requests
+ * @net: the applicable net namespace
+ * @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 net *net, struct tipc_bearer *b_ptr,
+ struct tipc_media_addr *dest)
+{
+ struct tipc_link_req *req;
+
+ req = kmalloc(sizeof(*req), GFP_ATOMIC);
+ if (!req)
+ return -ENOMEM;
+ req->buf = tipc_buf_acquire(MAX_H_SIZE);
+ if (!req->buf) {
+ kfree(req);
+ return -ENOMEM;
+ }
+
+ tipc_disc_init_msg(net, req->buf, DSC_REQ_MSG, b_ptr);
+ memcpy(&req->dest, dest, sizeof(*dest));
+ req->net = net;
+ req->bearer_id = b_ptr->identity;
+ req->domain = b_ptr->domain;
+ req->num_nodes = 0;
+ req->timer_intv = TIPC_LINK_REQ_INIT;
+ spin_lock_init(&req->lock);
+ setup_timer(&req->timer, disc_timeout, (unsigned long)req);
+ mod_timer(&req->timer, jiffies + req->timer_intv);
+ b_ptr->link_req = req;
+ tipc_bearer_send(net, req->bearer_id, req->buf, &req->dest);
+ 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)
+{
+ del_timer_sync(&req->timer);
+ kfree_skb(req->buf);
+ kfree(req);
+}
+
+/**
+ * tipc_disc_reset - reset object to send periodic link setup requests
+ * @net: the applicable net namespace
+ * @b_ptr: ptr to bearer issuing requests
+ * @dest_domain: network domain to which links can be established
+ */
+void tipc_disc_reset(struct net *net, struct tipc_bearer *b_ptr)
+{
+ struct tipc_link_req *req = b_ptr->link_req;
+
+ spin_lock_bh(&req->lock);
+ tipc_disc_init_msg(net, req->buf, DSC_REQ_MSG, b_ptr);
+ req->net = net;
+ req->bearer_id = b_ptr->identity;
+ req->domain = b_ptr->domain;
+ req->num_nodes = 0;
+ req->timer_intv = TIPC_LINK_REQ_INIT;
+ mod_timer(&req->timer, jiffies + req->timer_intv);
+ tipc_bearer_send(net, req->bearer_id, req->buf, &req->dest);
+ spin_unlock_bh(&req->lock);
+}
Code Review / kvmfornfv.git / blobdiff