iv/linux
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity
2f487712b8
linux/net/tipc/group.c
Jon Maloy 2f487712b8 tipc: guarantee that group broadcast doesn't bypass group unicast 
We need a mechanism guaranteeing that group unicasts sent out from a
socket are not bypassed by later sent broadcasts from the same socket.
We do this as follows:

- Each time a unicast is sent, we set a the broadcast method for the
  socket to "replicast" and "mandatory". This forces the first
  subsequent broadcast message to follow the same network and data path
  as the preceding unicast to a destination, hence preventing it from
  overtaking the latter.

- In order to make the 'same data path' statement above true, we let
  group unicasts pass through the multicast link input queue, instead
  of as previously through the unicast link input queue.

- In the first broadcast following a unicast, we set a new header flag,
  requiring all recipients to immediately acknowledge its reception.

- During the period before all the expected acknowledges are received,
  the socket refuses to accept any more broadcast attempts, i.e., by
  blocking or returning EAGAIN. This period should typically not be
  longer than a few microseconds.

- When all acknowledges have been received, the sending socket will
  open up for subsequent broadcasts, this time giving the link layer
  freedom to itself select the best transmission method.

- The forced and/or abrupt transmission method changes described above
  may lead to broadcasts arriving out of order to the recipients. We
  remedy this by introducing code that checks and if necessary
  re-orders such messages at the receiving end.

Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
Acked-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-13 08:46:01 -07:00

734 lines
17 KiB
C
Raw Blame History

/*
* net/tipc/group.c: TIPC group messaging code
*
* Copyright (c) 2017, Ericsson AB
* 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 "addr.h"
#include "group.h"
#include "bcast.h"
#include "server.h"
#include "msg.h"
#include "socket.h"
#include "node.h"
#include "name_table.h"
#include "subscr.h"
#define ADV_UNIT (((MAX_MSG_SIZE + MAX_H_SIZE) / FLOWCTL_BLK_SZ) + 1)
#define ADV_IDLE ADV_UNIT
#define ADV_ACTIVE (ADV_UNIT * 12)
enum mbr_state {
MBR_QUARANTINED,
MBR_DISCOVERED,
MBR_JOINING,
MBR_PUBLISHED,
MBR_JOINED,
MBR_LEAVING
};
struct tipc_member {
struct rb_node tree_node;
struct list_head list;
struct list_head congested;
struct sk_buff *event_msg;
struct sk_buff_head deferredq;
struct tipc_group *group;
u32 node;
u32 port;
u32 instance;
enum mbr_state state;
u16 advertised;
u16 window;
u16 bc_rcv_nxt;
u16 bc_acked;
bool usr_pending;
};
struct tipc_group {
struct rb_root members;
struct list_head congested;
struct tipc_nlist dests;
struct net *net;
int subid;
u32 type;
u32 instance;
u32 domain;
u32 scope;
u32 portid;
u16 member_cnt;
u16 bc_snd_nxt;
u16 bc_ackers;
bool loopback;
bool events;
};
static void tipc_group_proto_xmit(struct tipc_group *grp, struct tipc_member *m,
int mtyp, struct sk_buff_head *xmitq);
static int tipc_group_rcvbuf_limit(struct tipc_group *grp)
{
int mcnt = grp->member_cnt + 1;
/* Scale to bytes, considering worst-case truesize/msgsize ratio */
return mcnt * ADV_ACTIVE * FLOWCTL_BLK_SZ * 4;
}
u16 tipc_group_bc_snd_nxt(struct tipc_group *grp)
{
return grp->bc_snd_nxt;
}
static bool tipc_group_is_enabled(struct tipc_member *m)
{
return m->state != MBR_QUARANTINED && m->state != MBR_LEAVING;
}
static bool tipc_group_is_receiver(struct tipc_member *m)
{
return m && m->state >= MBR_JOINED;
}
u32 tipc_group_exclude(struct tipc_group *grp)
{
if (!grp->loopback)
return grp->portid;
return 0;
}
int tipc_group_size(struct tipc_group *grp)
{
return grp->member_cnt;
}
struct tipc_group *tipc_group_create(struct net *net, u32 portid,
struct tipc_group_req *mreq)
{
struct tipc_group *grp;
u32 type = mreq->type;
grp = kzalloc(sizeof(*grp), GFP_ATOMIC);
if (!grp)
return NULL;
tipc_nlist_init(&grp->dests, tipc_own_addr(net));
INIT_LIST_HEAD(&grp->congested);
grp->members = RB_ROOT;
grp->net = net;
grp->portid = portid;
grp->domain = addr_domain(net, mreq->scope);
grp->type = type;
grp->instance = mreq->instance;
grp->scope = mreq->scope;
grp->loopback = mreq->flags & TIPC_GROUP_LOOPBACK;
grp->events = mreq->flags & TIPC_GROUP_MEMBER_EVTS;
if (tipc_topsrv_kern_subscr(net, portid, type, 0, ~0, &grp->subid))
return grp;
kfree(grp);
return NULL;
}
void tipc_group_delete(struct net *net, struct tipc_group *grp)
{
struct rb_root *tree = &grp->members;
struct tipc_member *m, *tmp;
struct sk_buff_head xmitq;
__skb_queue_head_init(&xmitq);
rbtree_postorder_for_each_entry_safe(m, tmp, tree, tree_node) {
tipc_group_proto_xmit(grp, m, GRP_LEAVE_MSG, &xmitq);
list_del(&m->list);
kfree(m);
}
tipc_node_distr_xmit(net, &xmitq);
tipc_nlist_purge(&grp->dests);
tipc_topsrv_kern_unsubscr(net, grp->subid);
kfree(grp);
}
struct tipc_member *tipc_group_find_member(struct tipc_group *grp,
u32 node, u32 port)
{
struct rb_node *n = grp->members.rb_node;
u64 nkey, key = (u64)node << 32 | port;
struct tipc_member *m;
while (n) {
m = container_of(n, struct tipc_member, tree_node);
nkey = (u64)m->node << 32 | m->port;
if (key < nkey)
n = n->rb_left;
else if (key > nkey)
n = n->rb_right;
else
return m;
}
return NULL;
}
static struct tipc_member *tipc_group_find_dest(struct tipc_group *grp,
u32 node, u32 port)
{
struct tipc_member *m;
m = tipc_group_find_member(grp, node, port);
if (m && tipc_group_is_enabled(m))
return m;
return NULL;
}
static struct tipc_member *tipc_group_find_node(struct tipc_group *grp,
u32 node)
{
struct tipc_member *m;
struct rb_node *n;
for (n = rb_first(&grp->members); n; n = rb_next(n)) {
m = container_of(n, struct tipc_member, tree_node);
if (m->node == node)
return m;
}
return NULL;
}
static void tipc_group_add_to_tree(struct tipc_group *grp,
struct tipc_member *m)
{
u64 nkey, key = (u64)m->node << 32 | m->port;
struct rb_node **n, *parent = NULL;
struct tipc_member *tmp;
n = &grp->members.rb_node;
while (*n) {
tmp = container_of(*n, struct tipc_member, tree_node);
parent = *n;
tmp = container_of(parent, struct tipc_member, tree_node);
nkey = (u64)tmp->node << 32 | tmp->port;
if (key < nkey)
n = &(*n)->rb_left;
else if (key > nkey)
n = &(*n)->rb_right;
else
return;
}
rb_link_node(&m->tree_node, parent, n);
rb_insert_color(&m->tree_node, &grp->members);
}
static struct tipc_member *tipc_group_create_member(struct tipc_group *grp,
u32 node, u32 port,
int state)
{
struct tipc_member *m;
m = kzalloc(sizeof(*m), GFP_ATOMIC);
if (!m)
return NULL;
INIT_LIST_HEAD(&m->list);
INIT_LIST_HEAD(&m->congested);
__skb_queue_head_init(&m->deferredq);
m->group = grp;
m->node = node;
m->port = port;
m->bc_acked = grp->bc_snd_nxt - 1;
grp->member_cnt++;
tipc_group_add_to_tree(grp, m);
tipc_nlist_add(&grp->dests, m->node);
m->state = state;
return m;
}
void tipc_group_add_member(struct tipc_group *grp, u32 node, u32 port)
{
tipc_group_create_member(grp, node, port, MBR_DISCOVERED);
}
static void tipc_group_delete_member(struct tipc_group *grp,
struct tipc_member *m)
{
rb_erase(&m->tree_node, &grp->members);
grp->member_cnt--;
/* Check if we were waiting for replicast ack from this member */
if (grp->bc_ackers && less(m->bc_acked, grp->bc_snd_nxt - 1))
grp->bc_ackers--;
list_del_init(&m->list);
list_del_init(&m->congested);
/* If last member on a node, remove node from dest list */
if (!tipc_group_find_node(grp, m->node))
tipc_nlist_del(&grp->dests, m->node);
kfree(m);
}
struct tipc_nlist *tipc_group_dests(struct tipc_group *grp)
{
return &grp->dests;
}
void tipc_group_self(struct tipc_group *grp, struct tipc_name_seq *seq,
int *scope)
{
seq->type = grp->type;
seq->lower = grp->instance;
seq->upper = grp->instance;
*scope = grp->scope;
}
void tipc_group_update_member(struct tipc_member *m, int len)
{
struct tipc_group *grp = m->group;
struct tipc_member *_m, *tmp;
if (!tipc_group_is_enabled(m))
return;
m->window -= len;
if (m->window >= ADV_IDLE)
return;
if (!list_empty(&m->congested))
return;
/* Sort member into congested members' list */
list_for_each_entry_safe(_m, tmp, &grp->congested, congested) {
if (m->window > _m->window)
continue;
list_add_tail(&m->congested, &_m->congested);
return;
}
list_add_tail(&m->congested, &grp->congested);
}
void tipc_group_update_bc_members(struct tipc_group *grp, int len, bool ack)
{
u16 prev = grp->bc_snd_nxt - 1;
struct tipc_member *m;
struct rb_node *n;
for (n = rb_first(&grp->members); n; n = rb_next(n)) {
m = container_of(n, struct tipc_member, tree_node);
if (tipc_group_is_enabled(m)) {
tipc_group_update_member(m, len);
m->bc_acked = prev;
}
}
/* Mark number of acknowledges to expect, if any */
if (ack)
grp->bc_ackers = grp->member_cnt;
grp->bc_snd_nxt++;
}
bool tipc_group_cong(struct tipc_group *grp, u32 dnode, u32 dport,
int len, struct tipc_member **mbr)
{
struct sk_buff_head xmitq;
struct tipc_member *m;
int adv, state;
m = tipc_group_find_dest(grp, dnode, dport);
*mbr = m;
if (!m)
return false;
if (m->usr_pending)
return true;
if (m->window >= len)
return false;
m->usr_pending = true;
/* If not fully advertised, do it now to prevent mutual blocking */
adv = m->advertised;
state = m->state;
if (state < MBR_JOINED)
return true;
if (state == MBR_JOINED && adv == ADV_IDLE)
return true;
skb_queue_head_init(&xmitq);
tipc_group_proto_xmit(grp, m, GRP_ADV_MSG, &xmitq);
tipc_node_distr_xmit(grp->net, &xmitq);
return true;
}
bool tipc_group_bc_cong(struct tipc_group *grp, int len)
{
struct tipc_member *m = NULL;
/* If prev bcast was replicast, reject until all receivers have acked */
if (grp->bc_ackers)
return true;
if (list_empty(&grp->congested))
return false;
m = list_first_entry(&grp->congested, struct tipc_member, congested);
if (m->window >= len)
return false;
return tipc_group_cong(grp, m->node, m->port, len, &m);
}
/* tipc_group_sort_msg() - sort msg into queue by bcast sequence number
*/
static void tipc_group_sort_msg(struct sk_buff *skb, struct sk_buff_head *defq)
{
struct tipc_msg *_hdr, *hdr = buf_msg(skb);
u16 bc_seqno = msg_grp_bc_seqno(hdr);
struct sk_buff *_skb, *tmp;
int mtyp = msg_type(hdr);
/* Bcast may be bypassed by unicast or other bcast, - sort it in */
if (mtyp == TIPC_GRP_BCAST_MSG || mtyp == TIPC_GRP_MCAST_MSG) {
skb_queue_walk_safe(defq, _skb, tmp) {
_hdr = buf_msg(_skb);
if (!less(bc_seqno, msg_grp_bc_seqno(_hdr)))
continue;
__skb_queue_before(defq, _skb, skb);
return;
}
/* Bcast was not bypassed, - add to tail */
}
/* Unicasts are never bypassed, - always add to tail */
__skb_queue_tail(defq, skb);
}
/* tipc_group_filter_msg() - determine if we should accept arriving message
*/
void tipc_group_filter_msg(struct tipc_group *grp, struct sk_buff_head *inputq,
struct sk_buff_head *xmitq)
{
struct sk_buff *skb = __skb_dequeue(inputq);
bool ack, deliver, update;
struct sk_buff_head *defq;
struct tipc_member *m;
struct tipc_msg *hdr;
u32 node, port;
int mtyp, blks;
if (!skb)
return;
hdr = buf_msg(skb);
node = msg_orignode(hdr);
port = msg_origport(hdr);
if (!msg_in_group(hdr))
goto drop;
if (msg_is_grp_evt(hdr)) {
if (!grp->events)
goto drop;
__skb_queue_tail(inputq, skb);
return;
}
m = tipc_group_find_member(grp, node, port);
if (!tipc_group_is_receiver(m))
goto drop;
if (less(msg_grp_bc_seqno(hdr), m->bc_rcv_nxt))
goto drop;
TIPC_SKB_CB(skb)->orig_member = m->instance;
defq = &m->deferredq;
tipc_group_sort_msg(skb, defq);
while ((skb = skb_peek(defq))) {
hdr = buf_msg(skb);
mtyp = msg_type(hdr);
deliver = true;
ack = false;
update = false;
if (more(msg_grp_bc_seqno(hdr), m->bc_rcv_nxt))
break;
/* Decide what to do with message */
switch (mtyp) {
case TIPC_GRP_MCAST_MSG:
if (msg_nameinst(hdr) != grp->instance) {
update = true;
deliver = false;
}
/* Fall thru */
case TIPC_GRP_BCAST_MSG:
m->bc_rcv_nxt++;
ack = msg_grp_bc_ack_req(hdr);
break;
case TIPC_GRP_UCAST_MSG:
break;
default:
break;
}
/* Execute decisions */
__skb_dequeue(defq);
if (deliver)
__skb_queue_tail(inputq, skb);
else
kfree_skb(skb);
if (ack)
tipc_group_proto_xmit(grp, m, GRP_ACK_MSG, xmitq);
if (!update)
continue;
blks = msg_blocks(hdr);
tipc_group_update_rcv_win(grp, blks, node, port, xmitq);
}
return;
drop:
kfree_skb(skb);
}
void tipc_group_update_rcv_win(struct tipc_group *grp, int blks, u32 node,
u32 port, struct sk_buff_head *xmitq)
{
struct tipc_member *m;
m = tipc_group_find_member(grp, node, port);
if (!m)
return;
m->advertised -= blks;
switch (m->state) {
case MBR_JOINED:
if (m->advertised <= (ADV_ACTIVE - ADV_UNIT))
tipc_group_proto_xmit(grp, m, GRP_ADV_MSG, xmitq);
break;
case MBR_DISCOVERED:
case MBR_JOINING:
case MBR_LEAVING:
default:
break;
}
}
static void tipc_group_proto_xmit(struct tipc_group *grp, struct tipc_member *m,
int mtyp, struct sk_buff_head *xmitq)
{
struct tipc_msg *hdr;
struct sk_buff *skb;
int adv = 0;
skb = tipc_msg_create(GROUP_PROTOCOL, mtyp, INT_H_SIZE, 0,
m->node, tipc_own_addr(grp->net),
m->port, grp->portid, 0);
if (!skb)
return;
if (m->state == MBR_JOINED)
adv = ADV_ACTIVE - m->advertised;
hdr = buf_msg(skb);
if (mtyp == GRP_JOIN_MSG) {
msg_set_grp_bc_syncpt(hdr, grp->bc_snd_nxt);
msg_set_adv_win(hdr, adv);
m->advertised += adv;
} else if (mtyp == GRP_ADV_MSG) {
msg_set_adv_win(hdr, adv);
m->advertised += adv;
} else if (mtyp == GRP_ACK_MSG) {
msg_set_grp_bc_acked(hdr, m->bc_rcv_nxt);
}
__skb_queue_tail(xmitq, skb);
}
void tipc_group_proto_rcv(struct tipc_group *grp, bool *usr_wakeup,
struct tipc_msg *hdr, struct sk_buff_head *inputq,
struct sk_buff_head *xmitq)
{
u32 node = msg_orignode(hdr);
u32 port = msg_origport(hdr);
struct tipc_member *m;
if (!grp)
return;
m = tipc_group_find_member(grp, node, port);
switch (msg_type(hdr)) {
case GRP_JOIN_MSG:
if (!m)
m = tipc_group_create_member(grp, node, port,
MBR_QUARANTINED);
if (!m)
return;
m->bc_rcv_nxt = msg_grp_bc_syncpt(hdr);
m->window += msg_adv_win(hdr);
/* Wait until PUBLISH event is received */
if (m->state == MBR_DISCOVERED) {
m->state = MBR_JOINING;
} else if (m->state == MBR_PUBLISHED) {
m->state = MBR_JOINED;
*usr_wakeup = true;
m->usr_pending = false;
tipc_group_proto_xmit(grp, m, GRP_ADV_MSG, xmitq);
__skb_queue_tail(inputq, m->event_msg);
}
if (m->window < ADV_IDLE)
tipc_group_update_member(m, 0);
else
list_del_init(&m->congested);
return;
case GRP_LEAVE_MSG:
if (!m)
return;
/* Wait until WITHDRAW event is received */
if (m->state != MBR_LEAVING) {
m->state = MBR_LEAVING;
return;
}
/* Otherwise deliver already received WITHDRAW event */
__skb_queue_tail(inputq, m->event_msg);
*usr_wakeup = true;
tipc_group_delete_member(grp, m);
list_del_init(&m->congested);
return;
case GRP_ADV_MSG:
if (!m)
return;
m->window += msg_adv_win(hdr);
*usr_wakeup = m->usr_pending;
m->usr_pending = false;
list_del_init(&m->congested);
return;
case GRP_ACK_MSG:
if (!m)
return;
m->bc_acked = msg_grp_bc_acked(hdr);
if (--grp->bc_ackers)
break;
*usr_wakeup = true;
m->usr_pending = false;
return;
default:
pr_warn("Received unknown GROUP_PROTO message\n");
}
}
/* tipc_group_member_evt() - receive and handle a member up/down event
*/
void tipc_group_member_evt(struct tipc_group *grp,
bool *usr_wakeup,
int *sk_rcvbuf,
struct sk_buff *skb,
struct sk_buff_head *inputq,
struct sk_buff_head *xmitq)
{
struct tipc_msg *hdr = buf_msg(skb);
struct tipc_event *evt = (void *)msg_data(hdr);
u32 instance = evt->found_lower;
u32 node = evt->port.node;
u32 port = evt->port.ref;
int event = evt->event;
struct tipc_member *m;
struct net *net;
u32 self;
if (!grp)
goto drop;
net = grp->net;
self = tipc_own_addr(net);
if (!grp->loopback && node == self && port == grp->portid)
goto drop;
/* Convert message before delivery to user */
msg_set_hdr_sz(hdr, GROUP_H_SIZE);
msg_set_user(hdr, TIPC_CRITICAL_IMPORTANCE);
msg_set_type(hdr, TIPC_GRP_MEMBER_EVT);
msg_set_origport(hdr, port);
msg_set_orignode(hdr, node);
msg_set_nametype(hdr, grp->type);
msg_set_grp_evt(hdr, event);
m = tipc_group_find_member(grp, node, port);
if (event == TIPC_PUBLISHED) {
if (!m)
m = tipc_group_create_member(grp, node, port,
MBR_DISCOVERED);
if (!m)
goto drop;
/* Hold back event if JOIN message not yet received */
if (m->state == MBR_DISCOVERED) {
m->event_msg = skb;
m->state = MBR_PUBLISHED;
} else {
__skb_queue_tail(inputq, skb);
m->state = MBR_JOINED;
*usr_wakeup = true;
m->usr_pending = false;
}
m->instance = instance;
TIPC_SKB_CB(skb)->orig_member = m->instance;
tipc_group_proto_xmit(grp, m, GRP_JOIN_MSG, xmitq);
if (m->window < ADV_IDLE)
tipc_group_update_member(m, 0);
else
list_del_init(&m->congested);
} else if (event == TIPC_WITHDRAWN) {
if (!m)
goto drop;
TIPC_SKB_CB(skb)->orig_member = m->instance;
*usr_wakeup = true;
m->usr_pending = false;
/* Hold back event if more messages might be expected */
if (m->state != MBR_LEAVING && tipc_node_is_up(net, node)) {
m->event_msg = skb;
m->state = MBR_LEAVING;
} else {
__skb_queue_tail(inputq, skb);
tipc_group_delete_member(grp, m);
}
list_del_init(&m->congested);
}
*sk_rcvbuf = tipc_group_rcvbuf_limit(grp);
return;
drop:
kfree_skb(skb);
}
Reference in New Issue View Git Blame Copy Permalink