/* * 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].link; /* 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); }