[Tipc-discussion] check in some files for tipc realiable multicast

[Ling, X. <xia...@in...>]

Hi, Jon
    Guo Min and I have finished some initial code for tipc reliable
multicast.
this files are:
bcast.h
bcast.c
sendbcast.c=20
recvbcast.c
These file include routings used by reliable multicast.
The patch to some part has not checked in yet, so currently these codes
will affect others.

some explaining for the implementation.

1. We define a struct of bcastlink, it is derived from struct link. Each
bearer will has one corresponding=20
  bcastlink, it will be created in the link config process.
2. We define another struct of bcastlinkset, it is a set of bcastlink,
and one bcastlinkset will cover all=20
the nodes in the cluster.
3.A global array of bcastlinkset is used for blink_select, each
broadcast packet will be deliverd at one of the
bcastlinkset.
4.The policy of bcastlinkset array creation is: one bcastlink will only
in one bcastlinkset and one bcastlinkset will
try to include less bcastlink.
5. A bcast outqueue is defined as  "struct sk_buff_head bcast_outqueue",
it uses the "next and prev point" inside the struct sk_buff=20
to link the queue instead of UB(skb). That is because the UB(skb) point
is used in the queue of bcastlink for bearer congestion.=20