| /* |
| * net/tipc/discover.c |
| * |
| * Copyright (c) 2003-2006, 2014, 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 |
| * @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; |
| 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(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, 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); |
| 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(onode)) { |
| if (memcmp(&maddr, &bearer->addr, sizeof(maddr))) |
| disc_dupl_alert(bearer, tipc_own_addr, &maddr); |
| return; |
| } |
| if (!tipc_in_scope(ddom, tipc_own_addr)) |
| return; |
| if (!tipc_in_scope(bearer->domain, onode)) |
| return; |
| |
| /* Locate, or if necessary, create, node: */ |
| node = tipc_node_find(net, onode); |
| if (!node) |
| node = tipc_node_create(net, onode); |
| if (!node) |
| return; |
| |
| tipc_node_lock(node); |
| 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(INT_H_SIZE); |
| if (rbuf) { |
| tipc_disc_init_msg(net, rbuf, DSC_RESP_MSG, bearer); |
| tipc_bearer_send(bearer->identity, rbuf, &maddr); |
| kfree_skb(rbuf); |
| } |
| } |
| tipc_node_unlock(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->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(INT_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->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(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->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(req->bearer_id, req->buf, &req->dest); |
| spin_unlock_bh(&req->lock); |
| } |