/*
* net/tipc/discover.c
*
* Copyright (c) 2003-2006, 2014-2018, 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 "node.h"
#include "discover.h"
/* min delay during bearer start up */
#define TIPC_DISC_INIT msecs_to_jiffies(125)
/* max delay if bearer has no links */
#define TIPC_DISC_FAST msecs_to_jiffies(1000)
/* max delay if bearer has links */
#define TIPC_DISC_SLOW msecs_to_jiffies(60000)
/* indicates no timer in use */
#define TIPC_DISC_INACTIVE 0xffffffff
/**
* struct tipc_discoverer - 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
* @skb: request message to be (repeatedly) sent
* @timer: timer governing period between requests
* @timer_intv: current interval between requests (in ms)
*/
struct tipc_discoverer {
u32 bearer_id;
struct tipc_media_addr dest;
struct net *net;
u32 domain;
int num_nodes;
spinlock_t lock;
struct sk_buff *skb;
struct timer_list timer;
unsigned long timer_intv;
};
/**
* tipc_disc_init_msg - initialize a link setup message
* @net: the applicable net namespace
* @skb: buffer containing message
* @mtyp: message type (request or response)
* @b: ptr to bearer issuing message
*/
static void tipc_disc_init_msg(struct net *net, struct sk_buff *skb,
u32 mtyp, struct tipc_bearer *b)
{
struct tipc_net *tn = tipc_net(net);
u32 dest_domain = b->domain;
struct tipc_msg *hdr;
hdr = buf_msg(skb);
tipc_msg_init(tn->trial_addr, hdr, LINK_CONFIG, mtyp,
MAX_H_SIZE, dest_domain);
msg_set_size(hdr, MAX_H_SIZE + NODE_ID_LEN);
msg_set_non_seq(hdr, 1);
msg_set_node_sig(hdr, tn->random);
msg_set_node_capabilities(hdr, TIPC_NODE_CAPABILITIES);
msg_set_dest_domain(hdr, dest_domain);
msg_set_bc_netid(hdr, tn->net_id);
b->media->addr2msg(msg_media_addr(hdr), &b->addr);
msg_set_peer_net_hash(hdr, tipc_net_hash_mixes(net, tn->random));
msg_set_node_id(hdr, tipc_own_id(net));
}
static void tipc_disc_msg_xmit(struct net *net, u32 mtyp, u32 dst,
u32 src, u32 sugg_addr,
struct tipc_media_addr *maddr,
struct tipc_bearer *b)
{
struct tipc_msg *hdr;
struct sk_buff *skb;
skb = tipc_buf_acquire(MAX_H_SIZE + NODE_ID_LEN, GFP_ATOMIC);
if (!skb)
return;
hdr = buf_msg(skb);
tipc_disc_init_msg(net, skb, mtyp, b);
msg_set_sugg_node_addr(hdr, sugg_addr);
msg_set_dest_domain(hdr, dst);
tipc_bearer_xmit_skb(net, b->identity, skb, maddr);
}
/**
* disc_dupl_alert - issue node address duplication alert
* @b: 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, u32 node_addr,
struct tipc_media_addr *media_addr)
{
char media_addr_str[64];
tipc_media_addr_printf(media_addr_str, sizeof(media_addr_str),
media_addr);
pr_warn("Duplicate %x using %s seen on <%s>\n", node_addr,
media_addr_str, b->name);
}
/* tipc_disc_addr_trial(): - handle an address uniqueness trial from peer
* Returns true if message should be dropped by caller, i.e., if it is a
* trial message or we are inside trial period. Otherwise false.
*/
static bool tipc_disc_addr_trial_msg(struct tipc_discoverer *d,
struct tipc_media_addr *maddr,
struct tipc_bearer *b,
u32 dst, u32 src,
u32 sugg_addr,
u8 *peer_id,
int mtyp)
{
struct net *net = d->net;
struct tipc_net *tn = tipc_net(net);
u32 self = tipc_own_addr(net);
bool trial = time_before(jiffies, tn->addr_trial_end) && !self;
if (mtyp == DSC_TRIAL_FAIL_MSG) {
if (!trial)
return true;
/* Ignore if somebody else already gave new suggestion */
if (dst != tn->trial_addr)
return true;
/* Otherwise update trial address and restart trial period */
tn->trial_addr = sugg_addr;
msg_set_prevnode(buf_msg(d->skb), sugg_addr);
tn->addr_trial_end = jiffies + msecs_to_jiffies(1000);
return true;
}
/* Apply trial address if we just left trial period */
if (!trial && !self) {
schedule_work(&tn->work);
msg_set_prevnode(buf_msg(d->skb), tn->trial_addr);
msg_set_type(buf_msg(d->skb), DSC_REQ_MSG);
}
/* Accept regular link requests/responses only after trial period */
if (mtyp != DSC_TRIAL_MSG)
return trial;
sugg_addr = tipc_node_try_addr(net, peer_id, src);
if (sugg_addr)
tipc_disc_msg_xmit(net, DSC_TRIAL_FAIL_MSG, src,
self, sugg_addr, maddr, b);
return true;
}
/**
* tipc_disc_rcv - handle incoming discovery message (request or response)
* @net: applicable net namespace
* @skb: buffer containing message
* @b: bearer that message arrived on
*/
void tipc_disc_rcv(struct net *net, struct sk_buff *skb,
struct tipc_bearer *b)
{
struct tipc_net *tn = tipc_net(net);
struct tipc_msg *hdr = buf_msg(skb);
u32 pnet_hash = msg_peer_net_hash(hdr);
u16 caps = msg_node_capabilities(hdr);
bool legacy = tn->legacy_addr_format;
u32 sugg = msg_sugg_node_addr(hdr);
u32 signature = msg_node_sig(hdr);
u8 peer_id[NODE_ID_LEN] = {0,};
u32 dst = msg_dest_domain(hdr);
u32 net_id = msg_bc_netid(hdr);
struct tipc_media_addr maddr;
u32 src = msg_prevnode(hdr);
u32 mtyp = msg_type(hdr);
bool dupl_addr = false;
bool respond = false;
u32 self;
int err;
if (skb_linearize(skb)) {
kfree_skb(skb);
return;
}
hdr = buf_msg(skb);
if (caps & TIPC_NODE_ID128)
memcpy(peer_id, msg_node_id(hdr), NODE_ID_LEN);
else
sprintf(peer_id, "%x", src);
err = b->media->msg2addr(b, &maddr, msg_media_addr(hdr));
kfree_skb(skb);
if (err || maddr.broadcast) {
pr_warn_ratelimited("Rcv corrupt discovery message\n");
return;
}
/* Ignore discovery messages from own node */
if (!memcmp(&maddr, &b->addr, sizeof(maddr)))
return;
if (net_id != tn->net_id)
return;
if (tipc_disc_addr_trial_msg(b->disc, &maddr, b, dst,
src, sugg, peer_id, mtyp))
return;
self = tipc_own_addr(net);
/* Message from somebody using this node's address */
if (in_own_node(net, src)) {
disc_dupl_alert(b, self, &maddr);
return;
}
if (!tipc_in_scope(legacy, dst, self))
return;
if (!tipc_in_scope(legacy, b->domain, src))
return;
tipc_node_check_dest(net, src, peer_id, b, caps, signature, pnet_hash,
&maddr, &respond, &dupl_addr);
if (dupl_addr)
disc_dupl_alert(b, src, &maddr);
if (!respond)
return;
if (mtyp != DSC_REQ_MSG)
return;
tipc_disc_msg_xmit(net, DSC_RESP_MSG, src, self, 0, &maddr, b);
}
/* tipc_disc_add_dest - increment set of discovered nodes
*/
void tipc_disc_add_dest(struct tipc_discoverer *d)
{
spin_lock_bh(&d->lock);
d->num_nodes++;
spin_unlock_bh(&d->lock);
}
/* tipc_disc_remove_dest - decrement set of discovered nodes
*/
void tipc_disc_remove_dest(struct tipc_discoverer *d)
{
int intv, num;
spin_lock_bh(&d->lock);
d->num_nodes--;
num = d->num_nodes;
intv = d->timer_intv;
if (!num && (intv == TIPC_DISC_INACTIVE || intv > TIPC_DISC_FAST)) {
d->timer_intv = TIPC_DISC_INIT;
mod_timer(&d->timer, jiffies + d->timer_intv);
}
spin_unlock_bh(&d->lock);
}
/* tipc_disc_timeout - send a periodic link setup request
* Called whenever a link setup request timer associated with a bearer expires.
* - Keep doubling time between sent request until limit is reached;
* - Hold at fast polling rate if we don't have any associated nodes
* - Otherwise hold at slow polling rate
*/
static void tipc_disc_timeout(struct timer_list *t)
{
struct tipc_discoverer *d = from_timer(d, t, timer);
struct tipc_net *tn = tipc_net(d->net);
struct tipc_media_addr maddr;
struct sk_buff *skb = NULL;
struct net *net = d->net;
u32 bearer_id;
spin_lock_bh(&d->lock);
/* Stop searching if only desired node has been found */
if (tipc_node(d->domain) && d->num_nodes) {
d->timer_intv = TIPC_DISC_INACTIVE;
goto exit;
}
/* Did we just leave trial period ? */
if (!time_before(jiffies, tn->addr_trial_end) && !tipc_own_addr(net)) {
mod_timer(&d->timer, jiffies + TIPC_DISC_INIT);
spin_unlock_bh(&d->lock);
schedule_work(&tn->work);
return;
}
/* Adjust timeout interval according to discovery phase */
if (time_before(jiffies, tn->addr_trial_end)) {
d->timer_intv = TIPC_DISC_INIT;
} else {
d->timer_intv *= 2;
if (d->num_nodes && d->timer_intv > TIPC_DISC_SLOW)
d->timer_intv = TIPC_DISC_SLOW;
else if (!d->num_nodes && d->timer_intv > TIPC_DISC_FAST)
d->timer_intv = TIPC_DISC_FAST;
msg_set_type(buf_msg(d->skb), DSC_REQ_MSG);
msg_set_prevnode(buf_msg(d->skb), tn->trial_addr);
}
mod_timer(&d->timer, jiffies + d->timer_intv);
memcpy(&maddr, &d->dest, sizeof(maddr));
skb = skb_clone(d->skb, GFP_ATOMIC);
bearer_id = d->bearer_id;
exit:
spin_unlock_bh(&d->lock);
if (skb)
tipc_bearer_xmit_skb(net, bearer_id, skb, &maddr);
}
/**
* tipc_disc_create - create object to send periodic link setup requests
* @net: the applicable net namespace
* @b: ptr to bearer issuing requests
* @dest: destination address for request messages
* @skb: pointer to created frame
*
* Return: 0 if successful, otherwise -errno.
*/
int tipc_disc_create(struct net *net, struct tipc_bearer *b,
struct tipc_media_addr *dest, struct sk_buff **skb)
{
struct tipc_net *tn = tipc_net(net);
struct tipc_discoverer *d;
d = kmalloc(sizeof(*d), GFP_ATOMIC);
if (!d)
return -ENOMEM;
d->skb = tipc_buf_acquire(MAX_H_SIZE + NODE_ID_LEN, GFP_ATOMIC);
if (!d->skb) {
kfree(d);
return -ENOMEM;
}
tipc_disc_init_msg(net, d->skb, DSC_REQ_MSG, b);
/* Do we need an address trial period first ? */
if (!tipc_own_addr(net)) {
tn->addr_trial_end = jiffies + msecs_to_jiffies(1000);
msg_set_type(buf_msg(d->skb), DSC_TRIAL_MSG);
}
memcpy(&d->dest, dest, sizeof(*dest));
d->net = net;
d->bearer_id = b->identity;
d->domain = b->domain;
d->num_nodes = 0;
d->timer_intv = TIPC_DISC_INIT;
spin_lock_init(&d->lock);
timer_setup(&d->timer, tipc_disc_timeout, 0);
mod_timer(&d->timer, jiffies + d->timer_intv);
b->disc = d;
*skb = skb_clone(d->skb, GFP_ATOMIC);
return 0;
}
/**
* tipc_disc_delete - destroy object sending periodic link setup requests
* @d: ptr to link dest structure
*/
void tipc_disc_delete(struct tipc_discoverer *d)
{
timer_shutdown_sync(&d->timer);
kfree_skb(d->skb);
kfree(d);
}
/**
* tipc_disc_reset - reset object to send periodic link setup requests
* @net: the applicable net namespace
* @b: ptr to bearer issuing requests
*/
void tipc_disc_reset(struct net *net, struct tipc_bearer *b)
{
struct tipc_discoverer *d = b->disc;
struct tipc_media_addr maddr;
struct sk_buff *skb;
spin_lock_bh(&d->lock);
tipc_disc_init_msg(net, d->skb, DSC_REQ_MSG, b);
d->net = net;
d->bearer_id = b->identity;
d->domain = b->domain;
d->num_nodes = 0;
d->timer_intv = TIPC_DISC_INIT;
memcpy(&maddr, &d->dest, sizeof(maddr));
mod_timer(&d->timer, jiffies + d->timer_intv);
skb = skb_clone(d->skb, GFP_ATOMIC);
spin_unlock_bh(&d->lock);
if (skb)
tipc_bearer_xmit_skb(net, b->identity, skb, &maddr);
}
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