linux/net
Jon Paul Maloy 1a20cc254e tipc: introduce node contact FSM
The logics for determining when a node is permitted to establish
and maintain contact with its peer node becomes non-trivial in the
presence of multiple parallel links that may come and go independently.

A known failure scenario is that one endpoint registers both its links
to the peer lost, cleans up it binding table, and prepares for a table
update once contact is re-establihed, while the other endpoint may
see its links reset and re-established one by one, hence seeing
no need to re-synchronize the binding table. To avoid this, a node
must not allow re-establishing contact until it has confirmation that
even the peer has lost both links.

Currently, the mechanism for handling this consists of setting and
resetting two state flags from different locations in the code. This
solution is hard to understand and maintain. A closer analysis even
reveals that it is not completely safe.

In this commit we do instead introduce an FSM that keeps track of
the conditions for when the node can establish and maintain links.
It has six states and four events, and is strictly based on explicit
knowledge about the own node's and the peer node's contact states.
Only events leading to state change are shown as edges in the figure
below.

                             +--------------+
                             | SELF_UP/     |
           +---------------->| PEER_COMING  |-----------------+
    SELF_  |                 +--------------+                 |PEER_
    ESTBL_ |                        |                         |ESTBL_
    CONTACT|      SELF_LOST_CONTACT |                         |CONTACT
           |                        v                         |
           |                 +--------------+                 |
           |      PEER_      | SELF_DOWN/   |     SELF_       |
           |      LOST_   +--| PEER_LEAVING |<--+ LOST_       v
+-------------+   CONTACT |  +--------------+   | CONTACT  +-----------+
| SELF_DOWN/  |<----------+                     +----------| SELF_UP/  |
| PEER_DOWN   |<----------+                     +----------| PEER_UP   |
+-------------+   SELF_   |  +--------------+   | PEER_    +-----------+
           |      LOST_   +--| SELF_LEAVING/|<--+ LOST_       A
           |      CONTACT    | PEER_DOWN    |     CONTACT     |
           |                 +--------------+                 |
           |                         A                        |
    PEER_  |       PEER_LOST_CONTACT |                        |SELF_
    ESTBL_ |                         |                        |ESTBL_
    CONTACT|                 +--------------+                 |CONTACT
           +---------------->| PEER_UP/     |-----------------+
                             | SELF_COMING  |
                             +--------------+

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>
2015-07-20 20:41:16 -07:00
..
6lowpan 6lowpan: nhc: add other known rfc6282 compressions 2015-02-14 23:08:44 +01:00
9p Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2015-07-04 19:36:06 -07:00
802 net: Kill dev_rebuild_header 2015-03-02 16:43:41 -05:00
8021q vlan: Add GRO support for non hardware accelerated vlan 2015-06-01 16:50:52 -07:00
appletalk net: Pass kern from net_proto_family.create to sk_alloc 2015-05-11 10:50:17 -04:00
atm net: Pass kern from net_proto_family.create to sk_alloc 2015-05-11 10:50:17 -04:00
ax25 ax25: Stop using sock->sk_protinfo. 2015-06-28 16:55:44 -07:00
batman-adv batman-adv: change the MAC of each VLAN upon ndo_set_mac_address 2015-06-07 17:07:20 +02:00
bluetooth bluetooth: fix list handling 2015-07-04 19:11:33 -07:00
bridge bridge: mcast: fix br_multicast_dev_del warn when igmp snooping is not defined 2015-07-20 16:19:03 -07:00
caif Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2015-06-01 22:51:30 -07:00
can can: replace timestamp as unique skb attribute 2015-07-12 21:13:22 +02:00
ceph libceph: treat sockaddr_storage with uninitialized family as blank 2015-07-09 20:30:34 +03:00
core net: don't reforward packets already forwarded by offload device 2015-07-20 18:32:44 -07:00
dcb net/dcb: Add IEEE QCN attribute 2015-03-06 21:50:02 -05:00
dccp sock_diag: specify info_size per inet protocol 2015-06-15 19:49:22 -07:00
decnet net: Pass kern from net_proto_family.create to sk_alloc 2015-05-11 10:50:17 -04:00
dns_resolver
dsa net: dsa: Fix off-by-one in switch address parsing 2015-07-11 23:25:16 -07:00
ethernet net: Add full IPv6 addresses to flow_keys 2015-06-04 15:44:30 -07:00
hsr net/hsr: Fix NULL pointer dereference and refcnt bugs when deleting a HSR interface. 2015-03-01 13:40:23 -05:00
ieee802154 nl802154: export supported commands 2015-06-04 12:27:15 +02:00
ipv4 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2015-07-13 17:28:09 -07:00
ipv6 net/ipv6: update flowi6_oif in ip6_dst_lookup_flow if not set 2015-07-20 12:59:32 -07:00
ipx net: Pass kern from net_proto_family.create to sk_alloc 2015-05-11 10:50:17 -04:00
irda irda: use msecs_to_jiffies for conversion to jiffies 2015-05-25 17:46:21 -04:00
iucv net: Pass kern from net_proto_family.create to sk_alloc 2015-05-11 10:50:17 -04:00
key Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2015-06-24 16:49:49 -07:00
l2tp net: Modify sk_alloc to not reference count the netns of kernel sockets. 2015-05-11 10:50:18 -04:00
lapb
llc net: Pass kern from net_proto_family.create to sk_alloc 2015-05-11 10:50:17 -04:00
mac80211 Minor merge needed, due to function move. 2015-07-01 10:49:25 -07:00
mac802154 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2015-06-24 16:49:49 -07:00
mpls Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2015-06-13 23:56:52 -07:00
netfilter Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2015-07-13 17:28:09 -07:00
netlabel netlink: implement nla_put_in_addr and nla_put_in6_addr 2015-03-31 13:58:35 -04:00
netlink netlink: Delete an unnecessary check before the function call "module_put" 2015-07-03 09:27:43 -07:00
netrom netfilter: Remove spurios included of netfilter.h 2015-06-18 21:14:32 +02:00
nfc NFC: nci: fix mistake in uart generic driver 2015-06-15 18:10:37 +02:00
openvswitch Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2015-06-08 20:06:56 -07:00
packet Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2015-06-24 02:58:51 -07:00
phonet net: Pass kern from net_proto_family.create to sk_alloc 2015-05-11 10:50:17 -04:00
rds net-RDS: Delete an unnecessary check before the function call "module_put" 2015-07-03 09:27:42 -07:00
rfkill net: rfkill: gpio: make better use of gpiod API 2015-05-29 13:13:45 +02:00
rose Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2015-06-24 02:58:51 -07:00
rxrpc net: Pass kern from net_proto_family.create to sk_alloc 2015-05-11 10:50:17 -04:00
sched cls_cgroup: factor out classid retrieval 2015-07-20 12:41:30 -07:00
sctp sctp: Fix race between OOTB responce and route removal 2015-06-29 09:28:42 -07:00
sunrpc NFS client updates for Linux 4.2 2015-07-02 11:32:23 -07:00
switchdev switchdev: add offload_fwd_mark generator helper 2015-07-20 18:32:44 -07:00
tipc tipc: introduce node contact FSM 2015-07-20 20:41:16 -07:00
unix net/unix: support SCM_SECURITY for stream sockets 2015-06-10 22:49:20 -07:00
vmw_vsock net: Pass kern from net_proto_family.create to sk_alloc 2015-05-11 10:50:17 -04:00
wimax
wireless Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2015-06-13 23:56:52 -07:00
x25 net: Pass kern from net_proto_family.create to sk_alloc 2015-05-11 10:50:17 -04:00
xfrm Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2015-06-24 16:49:49 -07:00
Kconfig net: add CONFIG_NET_INGRESS to enable ingress filtering 2015-05-14 01:10:05 -04:00
Makefile mpls: Refactor how the mpls module is built 2015-03-04 00:26:06 -05:00
compat.c net: switch importing msghdr from userland to {compat_,}import_iovec() 2015-04-09 00:02:26 -04:00
socket.c net: Add a struct net parameter to sock_create_kern 2015-05-11 10:50:17 -04:00
sysctl_net.c