/* * 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) * @rcu: RCU head for deferred freeing */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;	struct rcu_head rcu;}; /** * 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 = timer_container_of(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_obj(*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;} static void tipc_disc_free_rcu(struct rcu_head *rp){	struct tipc_discoverer *d = container_of(rp, struct tipc_discoverer,						 rcu); 	kfree_skb(d->skb);	kfree(d);} /** * 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);	call_rcu(&d->rcu, tipc_disc_free_rcu);} /** * 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);}