Expand description
Mpstthree (also called MultiCrusty) is a library to write and check communication protocols based on Multiparty Session Types.
Currently this library is geared toward use with Scribble and New Scribble for full checking of protocols.
Example
Assume a simple protocol involving 3 participants, A, B and C. A sends a payload to B, then receives another payload from C. Upon receiving the payload from A, B sends a payload to C. This protocol can be written as A!B.A?C.B!C.0. To implement this example, first, get the right components from the library.
Here is the full working example, detailed afterwards:
// Used for the functions that will process the protocol
use std::boxed::Box;
use std::error::Error;
// Used for creating the types
use mpstthree::binary::struct_trait::{end::End, recv::Recv, send::Send};
use mpstthree::meshedchannels::MeshedChannels;
// Used for creating the stack and the name of each role
use mpstthree::role::a::RoleA;
use mpstthree::role::b::RoleB;
use mpstthree::role::c::RoleC;
use mpstthree::role::end::RoleEnd;
// Used inside the functions which process the protocol for receiving one payload
use mpstthree::functionmpst::recv::recv_mpst_a_from_c;
use mpstthree::functionmpst::recv::recv_mpst_b_from_a;
use mpstthree::functionmpst::recv::recv_mpst_c_from_b;
// Used inside the functions which process the protocol for sending one payload
use mpstthree::functionmpst::send::send_mpst_a_to_b;
use mpstthree::functionmpst::send::send_mpst_b_to_c;
use mpstthree::functionmpst::send::send_mpst_c_to_a;
// Used inside the functions which process the protocol for closing the connexion
use mpstthree::functionmpst::close::close_mpst;
// Used for connecting all the roles, represented as MeshedChannels, together
use mpstthree::functionmpst::fork::fork_mpst;
// Creating the binary sessions
// for A
type AtoB<N> = Send<N, End>;
type AtoC<N> = Recv<N, End>;
// for B
type BtoA<N> = Recv<N, End>;
type BtoC<N> = Send<N, End>;
// for C
type CtoA<N> = Send<N, End>;
type CtoB<N> = Recv<N, End>;
// Stacks
// for A
type StackA = RoleB<RoleC<RoleEnd>>;
// for B
type StackB = RoleA<RoleC<RoleEnd>>;
// for C
type StackC = RoleA<RoleB<RoleEnd>>;
// Creating the MP sessions
// for A
type EndpointA<N> = MeshedChannels<AtoB<N>, AtoC<N>, StackA, RoleA<RoleEnd>>;
// for B
type EndpointB<N> = MeshedChannels<BtoA<N>, BtoC<N>, StackB, RoleB<RoleEnd>>;
// for C
type EndpointC<N> = MeshedChannels<CtoA<N>, CtoB<N>, StackC, RoleC<RoleEnd>>;
// Function to process Endpoint of A
fn endpoint_a(s: EndpointA<i32>) -> Result<(), Box<dyn Error>> {
let s = send_mpst_a_to_b(1, s);
let (_x, s) = recv_mpst_a_from_c(s)?;
close_mpst(s)
}
// Function to process Endpoint of B
fn endpoint_b(s: EndpointB<i32>) -> Result<(), Box<dyn Error>> {
let (_x, s) = recv_mpst_b_from_a(s)?;
let s = send_mpst_b_to_c(2, s);
close_mpst(s)
}
// Function to process Endpoint of C
fn endpoint_c(s: EndpointC<i32>) -> Result<(), Box<dyn Error>> {
let s = send_mpst_c_to_a(3, s);
let (_x, s) = recv_mpst_c_from_b(s)?;
close_mpst(s)
}
// Fork all endpoints
fn main() {
let (thread_a, thread_b, thread_c) = fork_mpst(endpoint_a, endpoint_b, endpoint_c);
thread_a.join().unwrap();
thread_b.join().unwrap();
thread_c.join().unwrap();
}
Here is the full description. First, you import the correct functions and types.
// Used for the functions that will process the protocol
use std::boxed::Box;
use std::error::Error;
// Used for creating the types
use mpstthree::binary::struct_trait::{end::End, recv::Recv, send::Send};
use mpstthree::meshedchannels::MeshedChannels;
// Used for creating the stack and the name of each role
use mpstthree::role::a::RoleA;
use mpstthree::role::b::RoleB;
use mpstthree::role::c::RoleC;
use mpstthree::role::end::RoleEnd;
// Used inside the functions which process the protocol for receiving one payload
use mpstthree::functionmpst::recv::recv_mpst_a_from_c;
use mpstthree::functionmpst::recv::recv_mpst_b_from_a;
use mpstthree::functionmpst::recv::recv_mpst_c_from_b;
// Used inside the functions which process the protocol for sending one payload
use mpstthree::functionmpst::send::send_mpst_a_to_b;
use mpstthree::functionmpst::send::send_mpst_b_to_c;
use mpstthree::functionmpst::send::send_mpst_c_to_a;
// Used inside the functions which process the protocol for closing the connexion
use mpstthree::functionmpst::close::close_mpst;
// Used for connecting all the roles, represented as MeshedChannels, together
use mpstthree::functionmpst::fork::fork_mpst;
Then, you have to create the binary session types defining the interactions for each pair of participants. Note that each created type can be reused as many time as needed. For our example, we create several times the same binary session type for clarity, but we could use only two of those types for the whole protocol instead.
// Creating the binary sessions
// for A
type AtoB<N> = Send<N, End>;
type AtoC<N> = Recv<N, End>;
// for B
type BtoA<N> = Recv<N, End>;
type BtoC<N> = Send<N, End>;
// for C
type CtoA<N> = Send<N, End>;
type CtoB<N> = Recv<N, End>;
Add the stacks which give the correct order of the operations for each participant.
// Stacks
// for A
type StackA = RoleB<RoleC<RoleEnd>>;
// for B
type StackB = RoleA<RoleC<RoleEnd>>;
// for C
type StackC = RoleA<RoleB<RoleEnd>>;
You can now encapsulate those binary session types and stacks into MeshedChannels for each participant. We also add the names of the related roles.
// Creating the MP sessions
// for A
type EndpointA<N> = MeshedChannels<AtoB<N>, AtoC<N>, StackA, RoleA<RoleEnd>>;
// for B
type EndpointB<N> = MeshedChannels<BtoA<N>, BtoC<N>, StackB, RoleB<RoleEnd>>;
// for C
type EndpointC<N> = MeshedChannels<CtoA<N>, CtoB<N>, StackC, RoleC<RoleEnd>>;
To run the protocol, we need to detail the behaviour of the participants with functions that input the Endpoints defined above.
// Function to process Endpoint of A
fn simple_triple_endpoint_a(s: EndpointA<i32>) -> Result<(), Box<dyn Error>> {
let s = send_mpst_a_to_b(1, s);
let (x, s) = recv_mpst_a_from_c(s)?;
close_mpst(s)
}
// Function to process Endpoint of B
fn simple_triple_endpoint_b(s: EndpointB<i32>) -> Result<(), Box<dyn Error>> {
let (x, s) = recv_mpst_b_from_a(s)?;
let s = send_mpst_b_to_c(2, s);
close_mpst(s)
}
// Function to process Endpoint of C
fn simple_triple_endpoint_c(s: EndpointC<i32>) -> Result<(), Box<dyn Error>> {
let s = send_mpst_c_to_a(3, s);
let (x, s) = recv_mpst_c_from_b(s)?;
close_mpst(s)
}
In the end, you have to link/fork the threads, related to the functions above, together with fork_mpst(). Do not forget to unwrap() the returned threads.
// Fork all endpoints
fn main() {
let (thread_a, thread_b, thread_c) = fork_mpst(
endpoint_a,
endpoint_b,
endpoint_c,
);
thread_a.join().unwrap();
thread_b.join().unwrap();
thread_c.join().unwrap();
}
The different features available are:
default
: default features, for implementing the basic example above.macros_simple
: feature for implementing protocols with three participants, whatever are their name.macros_multiple
: feature for implementing protocols with any number of participants. Containsmacros_simple
.baking
: feature for implementing protocols with any number of participants and using associated functions instead of functions. Containsmacros_multiple
.transport_tcp
: feature containing primitives for communicating with TCP. Requiresopenssl
,pkg-config
andlibssl-dev
installed on your machine.transport_udp
: feature containing primitives for communicating with UDP. Requiresopenssl
,pkg-config
andlibssl-dev
installed on your machine.transport_http
: feature containing primitives for communicating with HTTP/HTTPS. Requiresopenssl
,pkg-config
andlibssl-dev
installed on your machine.transport
: feature containingtransport_tcp
,transport_udp
andtransport_http
.checking
: feature for the top-down approach. Needs theKMC
tool.full
: feature containingchecking
,baking
andtransport
.
Modules
This module contains the macro for attempting to run a block of code.
baking
This module contains the macros for creating the different structures and associated functions for any number of participants to simplify send/recv.
The slightly modified binary session type library.
checking
This module contains the macros and the functions for checking whether a protocol is well written or not, according to a bottom-up method.
This module contains all the functions that are used
for consuming MeshedChannels
.
interleaved
This module contains all the macros that are used for the interleaved sessions.
macros_multiple
This module contains all the macros that are used for the parametrisation on the number of participants.
macros_simple
This module contains all the macros that are used for the parametrisation on the name of the participants.
The main structure used for representing a participant, also named a party, within a protocol.
The main trait used for representing an ordering or the name of a participant.
The module for interacting with different modes of transport such as HTTP or TCP
Macros
Try to run the first block of code and,
upon error, run the second block of code.
Each step in the block of code must
return Result<Ok(_), Err(e)>
.
macros_multiple
Indefinitely loops to check all sessions if there
is a Cancel
signal and broadcast if it present.
Will also close correctly if a Stop
signal
is received.
baking
Create a new SessionMST structure, new roles and the baking environment.
This macro creates the related fork_mpst
function.
Create a new SessionMST structuren, new roles and the baking environment,
with send
functions that can fail.
Also create the macros needed for choosing branches.
Each macro is linked to a role X and are called as followed:
choose_mpst_x_to_all!(
s, # the current session
enum_1::variant_1, # the first branch for the first passive role
enum_2::variant_2, # the first branch for the second passive role
…
enum_n::variant_n, # the first branch for the n-th passive role
).
This macro does NOT create the related fork_mpst
function
to avoid conflicts for interleaved functions.
baking
Create a new SessionMST structure, new roles and the baking environment,
with send
functions that can fail.
This macro creates the related fork_mpst
function.
baking
Create a new SessionMST structuren, new roles and the baking environment.
Also create the macros needed for choosing branches.
Each macro is linked to a role X and are called as followed:
choose_mpst_x_to_all!(
s, # the current session
enum_1::variant_1, # the first branch for the first passive role
enum_2::variant_2, # the first branch for the second passive role
…
enum_n::variant_n, # the first branch for the n-th passive role
)
This macro creates the related fork_mpst
function.
Create a new SessionMST structuren, new roles and the baking environment,
with send
functions that can fail.
Also create the macros needed for choosing branches.
Each macro is linked to a role X and are called as followed:
choose_mpst_x_to_all!(
s, # the current session
enum_1::variant_1, # the first branch for the first passive role
enum_2::variant_2, # the first branch for the second passive role
…
enum_n::variant_n, # the first branch for the n-th passive role
)
This macro creates the related fork_mpst
function.
macros_multiple
Creates the structure MeshedChannels
create_meshedchannels
,
the close_mpst
and fork_mpst_multi
.
macros_multiple
Creates the structure MeshedChannels
create_meshedchannels
,
the close_mpst_cancel
and
fork_mpst_multi
functions to be used with more than 2 participants.
It checks the send sides of the channels along the recv sides.
checking
The macro that allows to create digraphs from each endpoint,
along with enum
if needed. You can also provide the name of
a file for running the KMC
tool and checking the
properties of the provided protocol: it will
return the minimal k
according to this tool if it exists,
and None
if k
is bigger than 50 or does not exist.
Choose between many different sessions wrapped in an
enum
Choose, for A, among two different sessions
Choose, for B, among two different sessions
Choose, for C, among two different sessions
macros_multiple
Create a macro that simplifies the usage of choose_mpst_multi_to_all
.
macros_multiple
Choose among different sessions that are provided, may fail because of a canceled session. Need to exclude the first participant
transport
or transport_http
Choose among different sessions that are provided.
macros_multiple
Choose among different sessions that are provided.
macros_simple
Choose among two different sessions.
Must be used with MeshedChannels
.
transport
or transport_tcp
Choose between many different sessions wrapped in an
enum
transport
or transport_udp
Choose between many different sessions wrapped in an
enum
macros_multiple
Create the close function to be used with more than 3 participants.
macros_multiple
Create the close function to be used with more than 3 participants. It is used for checking the send sides upon closing.
macros_multiple
Create the close function to be used with more than 3 participants.
macros_simple
macros_simple
macros_simple
Call both create_choose_right_from_1_to_2_and_3
and create_choose_left_from_1_to_2_and_3.
Must be used with MeshedChannels
.
macros_simple
Call both create_choose_right_from_2_to_1_and_3
and create_choose_left_from_2_to_1_and_3.
Must be used with MeshedChannels
.
macros_simple
Call both create_choose_right_from_3_to_1_and_2
and create_choose_left_from_3_to_1_and_2.
Must be used with MeshedChannels
.
macros_simple
Create the ChooseMpst function to send a Choose
left branch from the first role to the others. Must be
used with MeshedChannels
.
macros_simple
Create the ChooseMpst function to send a Choose
left branch from the second role to the others. Must be
used with MeshedChannels
.
macros_simple
Create the ChooseMpst function to send a Choose
left branch from the third role to the others. Must be
used with MeshedChannels
.
macros_multiple
Create the two ChooseMpst functions to send a Choose on each branch to be used with more than 3 participants. Only works when active role is the last one.
macros_multiple
Create the ChooseMpst function to send a Choose left branch to be used with more than 3 participants. Only works when active role is the last one.
macros_multiple
Create the ChooseMpst function to send a Choose right branch to be used with more than 3 participants. Only works when active role is the last one.
macros_simple
Create the ChooseMpst function to send a Choose
right branch from the first role to the others. Must be
used with MeshedChannels
.
macros_simple
Create the ChooseMpst function to send a Choose
right branch from the second role to the others. Must
be used with MeshedChannels
.
macros_simple
Create the ChooseMpst function to send a Choose
right branch from the third role to the others. Must be
used with MeshedChannels
.
macros_multiple
Create the ChooseMpst type to be used with more than 3 participants.
macros_multiple
Create choose fuunctions, to choose among different sessions that are provided.
macros_multiple
Create choose fuunctions, to choose among different sessions that are provided.
macros_multiple
Creates a MeshedChannels for more than 3 participants.
macros_simple
macros_simple
macros_simple
Create multiple new Role
and its dual.
macros_simple
Create multiple new Role
and its dual.
When a name X is given, the Roles created are
macros_simple
Create a new Role
and its dual.
macros_simple
Create a new Role
and its dual.
When a name X is given, the Roles created are
macros_simple
Create an offer function to recv on the first binary
session from any kind of role. Must be used with
MeshedChannels
.
macros_simple
Create an offer function to recv on the second binary
session from any kind of role. Must be used with
MeshedChannels
.
macros_multiple
Creates an OfferMpst function to receive an offer on a given binary session type of a MeshedChannels.
macros_multiple
Create the OfferMpst type to be used with more than 3 participants.
transport
or transport_http
Creates a recv function to receive from a simple role on a given binary session type of a MeshedChannels.
transport
or transport_http
Creates multiple recv functions to receive from a simple role on a given binary session type of a MeshedChannels.
macros_multiple
Creates a recv function to receive from a simple role on a given binary session type of a MeshedChannels.
macros_simple
Create a recv function to recv on the first binary
session from any kind of role. Must be used with
MeshedChannels
.
macros_simple
Create a recv function to recv on the second binary
session from any kind of role. Must be used with
MeshedChannels
.
macros_multiple
Creates multiple recv functions to receive from a simple role on a given binary session type of a MeshedChannels.
macros_multiple
Creates a send function to send from a given binary session type of a MeshedChannels with more than 3 participants. Checks if the first binary session has a “cancel” signal and panic if yes. The send function will try to send and panic if not possible (canceled session).
macros_multiple
Creates multiple send functions to send from a given binary session type of a MeshedChannels with more than 3 participants.
transport
or transport_http
Creates a send function to send from a given binary session type of a MeshedChannels with more than 3 participants.
macros_multiple
Creates a send function to send from a given binary session type of a MeshedChannels with more than 3 participants. The send function will try to send and panic if not possible (canceled session).
macros_multiple
Creates multiple send functions to send from a given binary session type of a MeshedChannels with more than 3 participants.
transport
or transport_http
Creates multiple send functions to send from a given binary session type of a MeshedChannels with more than 3 participants.
macros_multiple
Creates a send function to send from a given binary session type of a MeshedChannels with more than 3 participants.
macros_simple
Create a send function to send on the first binary
session from any kind of role. Must be used with
MeshedChannels
.
macros_simple
Create a send function to send on the second binary
session from any kind of role. Must be used with
MeshedChannels
.
macros_multiple
Creates multiple send functions to send from a given binary session type of a MeshedChannels with more than 3 participants.
macros_multiple
Creates the fork function to be used with more than 3 participants.
Offer a choice between many different sessions wrapped
in an enum
macros_multiple
Offer a choice and send the session to the broadcaster
macros_multiple
Offer a choice between many different sessions wrapped in an enum
. Used with http functions
macros_multiple
Offer a choice between many different sessions wrapped in an enum
Offer a choice to A from B between many different
sessions wrapped in an enum
Offer a choice to A from C between many different
sessions wrapped in an enum
Offer a choice to B from A between many different
sessions wrapped in an enum
Offer a choice to B from C between many different
sessions wrapped in an enum
Offer a choice to C from A between many different
sessions wrapped in an enum
Offer a choice to C from B between many different
sessions wrapped in an enum
transport
or transport_tcp
Offer a choice between many different sessions wrapped
in an enum
.
transport
or transport_udp
Offer a choice between many different sessions wrapped
in an enum
.
macros_multiple
Creates a function that will cancel a session and send a Cancel
signal to the broadcasting
role.