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remarkable-linux/net/tipc/bcast.c
Jon Paul Maloy 02d11ca200 tipc: transfer broadcast nacks in link state messages 
When we send broadcasts in clusters of more 70-80 nodes, we sometimes
see the broadcast link resetting because of an excessive number of
retransmissions. This is caused by a combination of two factors:

1) A 'NACK crunch", where loss of broadcast packets is discovered
   and NACK'ed by several nodes simultaneously, leading to multiple
   redundant broadcast retransmissions.

2) The fact that the NACKS as such also are sent as broadcast, leading
   to excessive load and packet loss on the transmitting switch/bridge.

This commit deals with the latter problem, by moving sending of
broadcast nacks from the dedicated BCAST_PROTOCOL/NACK message type
to regular unicast LINK_PROTOCOL/STATE messages. We allocate 10 unused
bits in word 8 of the said message for this purpose, and introduce a
new capability bit, TIPC_BCAST_STATE_NACK in order to keep the change
backwards compatible.

Reviewed-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-09-02 17:10:24 -07:00

425 lines
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/*
* net/tipc/bcast.c: TIPC broadcast code
*
* Copyright (c) 2004-2006, 2014-2015, Ericsson AB
* Copyright (c) 2004, Intel Corporation.
* Copyright (c) 2005, 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 <linux/tipc_config.h>
#include "socket.h"
#include "msg.h"
#include "bcast.h"
#include "name_distr.h"
#include "link.h"
#include "node.h"
#define BCLINK_WIN_DEFAULT 50 /* bcast link window size (default) */
#define BCLINK_WIN_MIN 32 /* bcast minimum link window size */
const char tipc_bclink_name[] = "broadcast-link";
/**
* struct tipc_bc_base - base structure for keeping broadcast send state
* @link: broadcast send link structure
* @inputq: data input queue; will only carry SOCK_WAKEUP messages
* @dest: array keeping number of reachable destinations per bearer
* @primary_bearer: a bearer having links to all broadcast destinations, if any
*/
struct tipc_bc_base {
struct tipc_link *link;
struct sk_buff_head inputq;
int dests[MAX_BEARERS];
int primary_bearer;
};
static struct tipc_bc_base *tipc_bc_base(struct net *net)
{
return tipc_net(net)->bcbase;
}
int tipc_bcast_get_mtu(struct net *net)
{
return tipc_link_mtu(tipc_bc_sndlink(net));
}
/* tipc_bcbase_select_primary(): find a bearer with links to all destinations,
* if any, and make it primary bearer
*/
static void tipc_bcbase_select_primary(struct net *net)
{
struct tipc_bc_base *bb = tipc_bc_base(net);
int all_dests = tipc_link_bc_peers(bb->link);
int i, mtu;
bb->primary_bearer = INVALID_BEARER_ID;
if (!all_dests)
return;
for (i = 0; i < MAX_BEARERS; i++) {
if (!bb->dests[i])
continue;
mtu = tipc_bearer_mtu(net, i);
if (mtu < tipc_link_mtu(bb->link))
tipc_link_set_mtu(bb->link, mtu);
if (bb->dests[i] < all_dests)
continue;
bb->primary_bearer = i;
/* Reduce risk that all nodes select same primary */
if ((i ^ tipc_own_addr(net)) & 1)
break;
}
}
void tipc_bcast_inc_bearer_dst_cnt(struct net *net, int bearer_id)
{
struct tipc_bc_base *bb = tipc_bc_base(net);
tipc_bcast_lock(net);
bb->dests[bearer_id]++;
tipc_bcbase_select_primary(net);
tipc_bcast_unlock(net);
}
void tipc_bcast_dec_bearer_dst_cnt(struct net *net, int bearer_id)
{
struct tipc_bc_base *bb = tipc_bc_base(net);
tipc_bcast_lock(net);
bb->dests[bearer_id]--;
tipc_bcbase_select_primary(net);
tipc_bcast_unlock(net);
}
/* tipc_bcbase_xmit - broadcast a packet queue across one or more bearers
*
* Note that number of reachable destinations, as indicated in the dests[]
* array, may transitionally differ from the number of destinations indicated
* in each sent buffer. We can sustain this. Excess destination nodes will
* drop and never acknowledge the unexpected packets, and missing destinations
* will either require retransmission (if they are just about to be added to
* the bearer), or be removed from the buffer's 'ackers' counter (if they
* just went down)
*/
static void tipc_bcbase_xmit(struct net *net, struct sk_buff_head *xmitq)
{
int bearer_id;
struct tipc_bc_base *bb = tipc_bc_base(net);
struct sk_buff *skb, *_skb;
struct sk_buff_head _xmitq;
if (skb_queue_empty(xmitq))
return;
/* The typical case: at least one bearer has links to all nodes */
bearer_id = bb->primary_bearer;
if (bearer_id >= 0) {
tipc_bearer_bc_xmit(net, bearer_id, xmitq);
return;
}
/* We have to transmit across all bearers */
skb_queue_head_init(&_xmitq);
for (bearer_id = 0; bearer_id < MAX_BEARERS; bearer_id++) {
if (!bb->dests[bearer_id])
continue;
skb_queue_walk(xmitq, skb) {
_skb = pskb_copy_for_clone(skb, GFP_ATOMIC);
if (!_skb)
break;
__skb_queue_tail(&_xmitq, _skb);
}
tipc_bearer_bc_xmit(net, bearer_id, &_xmitq);
}
__skb_queue_purge(xmitq);
__skb_queue_purge(&_xmitq);
}
/* tipc_bcast_xmit - deliver buffer chain to all nodes in cluster
* and to identified node local sockets
* @net: the applicable net namespace
* @list: chain of buffers containing message
* Consumes the buffer chain, except when returning -ELINKCONG
* Returns 0 if success, otherwise errno: -ELINKCONG,-EHOSTUNREACH,-EMSGSIZE
*/
int tipc_bcast_xmit(struct net *net, struct sk_buff_head *list)
{
struct tipc_link *l = tipc_bc_sndlink(net);
struct sk_buff_head xmitq, inputq, rcvq;
int rc = 0;
__skb_queue_head_init(&rcvq);
__skb_queue_head_init(&xmitq);
skb_queue_head_init(&inputq);
/* Prepare message clone for local node */
if (unlikely(!tipc_msg_reassemble(list, &rcvq)))
return -EHOSTUNREACH;
tipc_bcast_lock(net);
if (tipc_link_bc_peers(l))
rc = tipc_link_xmit(l, list, &xmitq);
tipc_bcast_unlock(net);
/* Don't send to local node if adding to link failed */
if (unlikely(rc)) {
__skb_queue_purge(&rcvq);
return rc;
}
/* Broadcast to all nodes, inluding local node */
tipc_bcbase_xmit(net, &xmitq);
tipc_sk_mcast_rcv(net, &rcvq, &inputq);
__skb_queue_purge(list);
return 0;
}
/* tipc_bcast_rcv - receive a broadcast packet, and deliver to rcv link
*
* RCU is locked, no other locks set
*/
int tipc_bcast_rcv(struct net *net, struct tipc_link *l, struct sk_buff *skb)
{
struct tipc_msg *hdr = buf_msg(skb);
struct sk_buff_head *inputq = &tipc_bc_base(net)->inputq;
struct sk_buff_head xmitq;
int rc;
__skb_queue_head_init(&xmitq);
if (msg_mc_netid(hdr) != tipc_netid(net) || !tipc_link_is_up(l)) {
kfree_skb(skb);
return 0;
}
tipc_bcast_lock(net);
if (msg_user(hdr) == BCAST_PROTOCOL)
rc = tipc_link_bc_nack_rcv(l, skb, &xmitq);
else
rc = tipc_link_rcv(l, skb, NULL);
tipc_bcast_unlock(net);
tipc_bcbase_xmit(net, &xmitq);
/* Any socket wakeup messages ? */
if (!skb_queue_empty(inputq))
tipc_sk_rcv(net, inputq);
return rc;
}
/* tipc_bcast_ack_rcv - receive and handle a broadcast acknowledge
*
* RCU is locked, no other locks set
*/
void tipc_bcast_ack_rcv(struct net *net, struct tipc_link *l, u32 acked)
{
struct sk_buff_head *inputq = &tipc_bc_base(net)->inputq;
struct sk_buff_head xmitq;
__skb_queue_head_init(&xmitq);
tipc_bcast_lock(net);
tipc_link_bc_ack_rcv(l, acked, &xmitq);
tipc_bcast_unlock(net);
tipc_bcbase_xmit(net, &xmitq);
/* Any socket wakeup messages ? */
if (!skb_queue_empty(inputq))
tipc_sk_rcv(net, inputq);
}
/* tipc_bcast_synch_rcv - check and update rcv link with peer's send state
*
* RCU is locked, no other locks set
*/
int tipc_bcast_sync_rcv(struct net *net, struct tipc_link *l,
struct tipc_msg *hdr)
{
struct sk_buff_head *inputq = &tipc_bc_base(net)->inputq;
struct sk_buff_head xmitq;
int rc = 0;
__skb_queue_head_init(&xmitq);
tipc_bcast_lock(net);
if (msg_type(hdr) == STATE_MSG) {
tipc_link_bc_ack_rcv(l, msg_bcast_ack(hdr), &xmitq);
rc = tipc_link_bc_sync_rcv(l, hdr, &xmitq);
} else {
tipc_link_bc_init_rcv(l, hdr);
}
tipc_bcast_unlock(net);
tipc_bcbase_xmit(net, &xmitq);
/* Any socket wakeup messages ? */
if (!skb_queue_empty(inputq))
tipc_sk_rcv(net, inputq);
return rc;
}
/* tipc_bcast_add_peer - add a peer node to broadcast link and bearer
*
* RCU is locked, node lock is set
*/
void tipc_bcast_add_peer(struct net *net, struct tipc_link *uc_l,
struct sk_buff_head *xmitq)
{
struct tipc_link *snd_l = tipc_bc_sndlink(net);
tipc_bcast_lock(net);
tipc_link_add_bc_peer(snd_l, uc_l, xmitq);
tipc_bcbase_select_primary(net);
tipc_bcast_unlock(net);
}
/* tipc_bcast_remove_peer - remove a peer node from broadcast link and bearer
*
* RCU is locked, node lock is set
*/
void tipc_bcast_remove_peer(struct net *net, struct tipc_link *rcv_l)
{
struct tipc_link *snd_l = tipc_bc_sndlink(net);
struct sk_buff_head *inputq = &tipc_bc_base(net)->inputq;
struct sk_buff_head xmitq;
__skb_queue_head_init(&xmitq);
tipc_bcast_lock(net);
tipc_link_remove_bc_peer(snd_l, rcv_l, &xmitq);
tipc_bcbase_select_primary(net);
tipc_bcast_unlock(net);
tipc_bcbase_xmit(net, &xmitq);
/* Any socket wakeup messages ? */
if (!skb_queue_empty(inputq))
tipc_sk_rcv(net, inputq);
}
int tipc_bclink_reset_stats(struct net *net)
{
struct tipc_link *l = tipc_bc_sndlink(net);
if (!l)
return -ENOPROTOOPT;
tipc_bcast_lock(net);
tipc_link_reset_stats(l);
tipc_bcast_unlock(net);
return 0;
}
static int tipc_bc_link_set_queue_limits(struct net *net, u32 limit)
{
struct tipc_link *l = tipc_bc_sndlink(net);
if (!l)
return -ENOPROTOOPT;
if (limit < BCLINK_WIN_MIN)
limit = BCLINK_WIN_MIN;
if (limit > TIPC_MAX_LINK_WIN)
return -EINVAL;
tipc_bcast_lock(net);
tipc_link_set_queue_limits(l, limit);
tipc_bcast_unlock(net);
return 0;
}
int tipc_nl_bc_link_set(struct net *net, struct nlattr *attrs[])
{
int err;
u32 win;
struct nlattr *props[TIPC_NLA_PROP_MAX + 1];
if (!attrs[TIPC_NLA_LINK_PROP])
return -EINVAL;
err = tipc_nl_parse_link_prop(attrs[TIPC_NLA_LINK_PROP], props);
if (err)
return err;
if (!props[TIPC_NLA_PROP_WIN])
return -EOPNOTSUPP;
win = nla_get_u32(props[TIPC_NLA_PROP_WIN]);
return tipc_bc_link_set_queue_limits(net, win);
}
int tipc_bcast_init(struct net *net)
{
struct tipc_net *tn = tipc_net(net);
struct tipc_bc_base *bb = NULL;
struct tipc_link *l = NULL;
bb = kzalloc(sizeof(*bb), GFP_ATOMIC);
if (!bb)
goto enomem;
tn->bcbase = bb;
spin_lock_init(&tipc_net(net)->bclock);
if (!tipc_link_bc_create(net, 0, 0,
U16_MAX,
BCLINK_WIN_DEFAULT,
0,
&bb->inputq,
NULL,
NULL,
&l))
goto enomem;
bb->link = l;
tn->bcl = l;
return 0;
enomem:
kfree(bb);
kfree(l);
return -ENOMEM;
}
void tipc_bcast_stop(struct net *net)
{
struct tipc_net *tn = net_generic(net, tipc_net_id);
synchronize_net();
kfree(tn->bcbase);
kfree(tn->bcl);
}
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