paper4—Multi-MPE_Trigger_Algorithm—temp

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Description: when SMD start, this algorithm will run as a deamon, two roles: Master,
Slave. When the SMD is elected as a Master role, then, the MPE will be the master MPE accessed by other SMD, and related process data will backup to other
SMD (Slave MPE).

ctrl: Master or Slave, this value is set by batman-adv;

ctrl=0, SMD is Slave role;

ctrl=1, SMD is elected as a Master role;

changed: Master or Slave, this value is set by batman-adv;

changed=0, Master SMD is not changed, so, do not need to create thread in MAIN again for data synchronization;

changed=1, Master SMD is changed, so, need to create thread in MAIN again for data synchronization;

changed=0;

is_me=-1;

prev_state=-1; //0:Slave; 1:Master;

//READ_CTRL, set URL of application system. Access master_ip in browser.

PROCEDURE: READ_CTRL

prev_ip=0.0.0.0;

while true do

read the value of ctrl set by batman-adv;

read master_ip of Master SMD;

if master_ip==me_ip and is_me!=-1 then

prev_state=is_me;

is_me=1;

else if master_ip!=me_ip and is_me!=-1 then

prev_state=is_me;

is_me=0;

end if

if master_ip!=prev_ip then

changed=1;

prev_ip=master_ip;

add (or update) "master_ip mpe.localhost" in /etc/hosts;

end if

sleep 1s;

done

END PROCEDURE READ_CTRL

//******************************
MAIN Thread

PROCEDURE: MAIN

pthread_create(READ_CTRL);

sleep 1s; //waiting for READ_CTRL to read the value of ctrl and master_ip of Master SMD

start=1; //set initial state

while true do

if start==1 and ctrl==1 then

start=0;

is_me=1;

pthread_create(Master);

pthread_join(Master);

else if start==1 and ctrl==0 then

start=0;

is_me=0;

pthread_create(Slave);

pthread_join(Slave);

else if start==0 and changed==1 and ctrl==1 then

pthread_create(Master);

pthread_join(Master);

else if start==0 and changed==1 and ctrl==0 then

sleep(2); //waiting master initialize

pthread_create(Master);

pthread_join(Master);

else //start==0 and changed==0

continue;

end if

done

END PROCEDURE MAIN

//******************************
Master Thread

PROCEDURE: Master

socket();

bind();

listen();

while true do

accept(); //waiting for connect from Slave

pthread_create(M_THREAD);

done

END PROCEDURE Master

//******************************
M_THREAD Thread

PROCEDURE: M_THREAD

while true do //communication between Master & Slave

if database updating then

send synchronous data to Slave;

end if

done

END PROCEDURE M_THREAD

//******************************
Slave Thread

PROCEDURE: Slave

socket();

connect();

while true do

if receive synchronous data from Master then

update database;

end if

done

END PROCEDURE Slave