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/*
* PROMELA Validation Model
* FLOW CONTROL LAYER VALIDATION
*/
/* see end of file for LTL properties */
#define LOSS 1 /* message loss */
#define DUPS 0 /* duplicate msgs */
#define QSZ 2 /* queue size */
mtype = {
red, white, blue,
abort, accept, ack, sync_ack, close, connect,
create, data, eof, open, reject, sync, transfer,
FATAL, NON_FATAL, COMPLETE
}
chan ses_to_flow[2] = [QSZ] of { byte, byte };
chan flow_to_ses[2] = [QSZ] of { byte, byte };
chan dll_to_flow[2] = [QSZ] of { byte, byte };
/*
* Flow Control Layer Validation Model
*/
#define true 1
#define false 0
#define M 4 /* range sequence numbers */
#define W 2 /* window size: M/2 */
proctype fc(chan s2f, f2d, f2s, d2f)
{ bool busy[M]; /* outstanding messages */
byte q; /* seq# oldest unacked msg */
byte m; /* seq# last msg received */
byte s; /* seq# next msg to send */
byte window; /* nr of outstanding msgs */
byte type; /* msg type */
bit received[M]; /* receiver housekeeping */
bit x; /* scratch variable */
byte p; /* seq# of last msg acked */
byte I_buf[M], O_buf[M]; /* message buffers */
xr s2f;
xs f2d;
xs f2s;
xr d2f;
/* sender part */
end: do
:: atomic {
(window < W && nempty(s2f)
&& nfull(f2d)) ->
s2f?type,x;
window = window + 1;
busy[s] = true;
O_buf[s] = type;
f2d!type,s;
if
:: (type != sync) ->
s = (s+1)%M
:: (type == sync) ->
window = 0;
s = M;
do
:: (s > 0) ->
s = s-1;
busy[s] = false
:: (s == 0) ->
break
od
fi
}
:: atomic {
(window > 0 && busy[q] == false) ->
window = window - 1;
q = (q+1)%M
}
#if DUPS
:: atomic {
(nfull(f2d) && window > 0 && busy[q] == true) ->
f2d!O_buf[q],q
}
#endif
:: atomic {
(timeout && nfull(f2d) && window > 0 && busy[q] == true) ->
f2d!O_buf[q],q
}
/* receiver part */
#if LOSS
:: d2f?type,m /* lose any message */
#endif
:: d2f?type,m ->
if
:: atomic {
(type == ack) ->
busy[m] = false
}
:: atomic {
(type == sync) ->
m = 0;
do
:: (m < M) ->
received[m] = 0;
m = m+1
:: (m == M) ->
break
od
}; f2d!sync_ack,0
:: (type == sync_ack) ->
f2s!sync_ack,0
:: (type != ack && type != sync && type != sync_ack)->
if
:: atomic {
(received[m] == true) ->
x = ((0<p-m && p-m<=W)
|| (0<p-m+M && p-m+M<=W)) };
if
:: (x) -> f2d!ack,m
:: (!x) /* else skip */
fi
:: atomic {
(received[m] == false) ->
I_buf[m] = type;
received[m] = true;
received[(m-W+M)%M] = false
}
fi
fi
:: /* atomic { */
(received[p] == true && nfull(f2s) && nfull(f2d)) ->
f2s!I_buf[p],0;
f2d!ack,p;
p = (p+1)%M
/* } */
od
}
proctype upper_s(chan s2f, f2s0)
{ byte s_state;
byte type, toggle;
xs s2f;
xr f2s0;
s2f!sync,toggle;
do
:: f2s0?sync_ack,type ->
if
:: (type != toggle)
:: (type == toggle) -> break
fi
:: timeout ->
s2f!sync,toggle
od;
toggle = 1 - toggle;
end: do
:: s2f!white,0
:: atomic {
(s_state == 0 && nfull(s2f)) ->
s2f!red,0 ->
s_state = 1
}
:: atomic {
(s_state == 1 && nfull(s2f)) ->
s2f!blue,0 ->
s_state = 2
}
od
}
proctype upper_r(chan f2s1)
{ byte r_state;
xr f2s1;
do
:: f2s1?white,0
:: f2s1?red,0 -> break
:: f2s1?blue,0 -> assert(0)
od;
do
:: f2s1?white,0
:: f2s1?red,0 -> assert(0)
:: f2s1?blue,0 -> goto end
od;
end:
do
:: f2s1?white,0
:: f2s1?red,0 -> assert(0)
:: f2s1?blue,0 -> assert(0)
od
}
init
{
atomic {
run fc(ses_to_flow[0], dll_to_flow[1], flow_to_ses[0], dll_to_flow[0]);
run fc(ses_to_flow[1], dll_to_flow[0], flow_to_ses[1], dll_to_flow[1]);
run upper_s(ses_to_flow[0], flow_to_ses[0]);
run upper_r(flow_to_ses[1])
}
}
ltl p1 { ( len(flow_to_ses[1]) > 0 -> flow_to_ses[1]?[white]) U ( flow_to_ses[1]?[red] ) }
ltl p2 { (!(flow_to_ses[1]?[blue])) U (flow_to_ses[1]?[red]) }
ltl p3 { <> (flow_to_ses[1]?[blue]) }
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