diff options
Diffstat (limited to 'net/tipc/discover.c')
| -rw-r--r-- | net/tipc/discover.c | 418 |
1 files changed, 418 insertions, 0 deletions
diff --git a/net/tipc/discover.c b/net/tipc/discover.c new file mode 100644 index 000000000..967e292f5 --- /dev/null +++ b/net/tipc/discover.c @@ -0,0 +1,418 @@ +/* + * 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); +} |