Skip to content

Commit

Permalink
Revisions to pseudo code
Browse files Browse the repository at this point in the history
  • Loading branch information
@systemzax
systemzax committed Dec 11, 2023
1 parent 9bb5575 commit bb6e688
Showing 1 changed file with 121 additions and 42 deletions.
163 changes: 121 additions & 42 deletions libraries/chain/hotstuff/hs_pseudo
View file
Original file line number Diff line number Diff line change
@@ -1,11 +1,19 @@
//notes : under this pseudo code, the hotstuff information is mapped to Antelope concepts :
b_leaf (becomes) -> block_header_state.id

b_leaf (becomes) -> block_header_state.id //block_state pointer to head

b_lock (becomes) -> finalizer_safety_information.locked_block_ref
b_exec (becomes) -> block proposal refered to by block_header_state_core.last_final_block_height

b_exec (becomes) -> block proposal refered to by block_header_state_core.last_final_block_height //head->last_final_block_height

v_height (becomes) -> finalizer_safety_information.last_vote_block_ref
high_qc (becomes) -> block proposal refered to by block_header_state_core.last_qc_block_height

high_qc (becomes) -> block proposal refered to by block_header_state_core.last_qc_block_height //fork_db.get_block_by_height(head, head->last_qc_block_height).get_best_qc()

proposal_store is now fork_db



//structures

struct finalizer_authority {
Expand Down Expand Up @@ -70,26 +78,71 @@ struct block_header_state_core {
}
}

struct building_block_input {
block_id_type previous;
block_timestamp_type timestamp;
account_name producer;
vector<digest_type> new_protocol_feature_activations;
};

// this struct can be extracted from a building block
struct assembled_block_input : public building_block_input {
digest_type transaction_mroot;
digest_type action_mroot;
std::optional<proposer_policy> new_proposer_policy;
std::optional<finalizer_policy> new_finalizer_policy;
std::optional<quorum_certificate> qc; // assert(qc.block_height <= num_from_id(previous));
};

struct block_header_state {

//existing block_header_state members
sha256 id; //b_leaf under hotstuff

sha256 id; //b_leaf under hotstuff

[...] //other existing block_header_state members

protocol_feature_activation_set_ptr activated_protocol_features;

//new additions
sha256 finalizer_digest;
block_header_state_core core;
incremental_block_mtree proposal_mtree;
incremental_block_mtree finality_mtree;
uint32_t policy_generation;

block_header_state_core core;
incremental_block_mtree proposal_mtree;
incremental_block_mtree finality_mtree;

finalizer_policy_ptr finalizer_policy; // finalizer set + threshold + generation, supports `digest()`
proposer_policy_ptr proposer_policy; // producer authority schedule, supports `digest()`

flat_map<uint32_t, proposer_policy_ptr> proposer_policies;
flat_map<uint32_t, finalizer_policy_ptr> finalizer_policies;


block_header_state next(const assembled_block_input& data) const {


}

sha256 compute_finalizer_digest() const {

}

}

//shared pointer to a block_state
struct block_handle {
block_state_ptr _handle;
}

struct block_state {
sha256 finalizer_digest;
block_header_state_ptr bhs;
finalizer_policy_ptr fp;
finalizer_policy_ptr active_fp;
std::optional<pending_quorum_certificate> pending_qc;
std::optional<valid_quorum_certificate> valid_qc;
block_id_type id() const {return bhs->id;}
uint64_t get_height() const {return block_header::num_from_id(bhs->id);}
quorum_certificate get_best_qc() { [...] //return the best QC available }

}

//this structure holds the required information and methods for the Hotstuff algorithm. It is derived from a block and block_header content, notably extensions
Expand Down Expand Up @@ -148,8 +201,11 @@ struct hs_vote_message {

//added as a block_header extension before signing
struct hotstuff_header_extension {
uint32_t last_qc_block_height;
bool is_last_qc_strong;
uint32_t last_qc_block_height;
bool is_last_qc_strong;

std::optional<finalizer_policy> new_finalizer_policy;
std::optional<proposer_policy> new_proposer_policy;
}

//added as a block extension before broadcast
Expand All @@ -174,8 +230,10 @@ sha256 get_proposal_digest(block_header_state bhs, signed_block p, bool weak){
return digest;
}

hotstuff_header_extension construct_hotstuff_header_extension(quorum_certificate qc){
return {qc.block_height, qc.is_strong()};
//
hotstuff_header_extension construct_hotstuff_header_extension(quorum_certificate qc, std::optional<finalizer_policy> new_finalizer_policy, std::optional<proposer_policy> new_proposer_policy){
return {qc.block_height, qc.is_strong(), new_finalizer_policy, new_proposer_policy};

}

hotstuff_block_extension construct_hotstuff_block_extension(quorum_certificate qc){
Expand All @@ -199,16 +257,10 @@ bool extends(hs_proposal descendant, hs_proposal ancestor){
void update_pending_qc(hs_vote_message v, block_handle& bc){
if (bc.valid_qc.has_value()) return; //can only update a pending qc
pending_quorum_certificate pqc = bc.pending_qc.value();

//update the current pending_quorum_certificate with new vote information
[...] //abstracted
if (pqc.strong_quorum_met()){
bc.bhs.core = bc.bhs.core.next(bc.get_height(), true); //f1
//todo : f2
}
else if (pqc.weak_quorum_met()){
bc.bhs.core = bc.bhs.core.next(bc.get_height(), false); //f1
//todo : f2
}

}

hs_proposal extract_proposal(signed_block sb, block_handle& bc){
Expand All @@ -223,7 +275,7 @@ enum VoteDecision {
NoVote
}

VoteDecision decide_vote(hs_proposal p, finalizer_safety_information& fsi, block_handle& bc){
VoteDecision decide_vote(finalizer_safety_information& fsi, block_handle p){

bool monotony_check = false;
bool safety_check = false;
Expand All @@ -245,7 +297,7 @@ VoteDecision decide_vote(hs_proposal p, finalizer_safety_information& fsi, block
//Safety check : check if this proposal extends the proposal we're locked on
if (extends(p, fork_db.get_block_by_id(fsi.locked_block_ref)) safety_check = true;
//Liveness check : check if the height of this proposal's justification is higher than the height of the proposal I'm locked on. This allows restoration of liveness if a replica is locked on a stale proposal
if (fork_db.get_block_by_height(bc.id(), p.last_qc_block_height).timestamp > fork_db.get_block_by_id(fsi.locked_block_ref).timestamp)) liveness_check = true;
if (fork_db.get_block_by_height(p.id(), p.last_qc_block_height).timestamp > fork_db.get_block_by_id(fsi.locked_block_ref).timestamp)) liveness_check = true;
}
else {
//if we're not locked on anything, means the protocol feature just activated and we can proceed
Expand All @@ -254,21 +306,31 @@ VoteDecision decide_vote(hs_proposal p, finalizer_safety_information& fsi, block
}

if (monotony_check && (liveness_check || safety_check)){
uint32_t new_vote_range_lower_bound = fork_db.get_block_by_height(p.block_id, p.last_qc_block_height).timestamp;
uint32_t new_vote_range_upper_bound = p.timestamp;
bool time_range_interference = fsi.last_vote_range_lower_bound < new_vote_range_upper_bound && new_vote_range_lower_bound < fsi.last_vote_range_upper_bound;

uint32_t requested_vote_range_lower_bound = fork_db.get_block_by_height(p.block_id, p.last_qc_block_height).timestamp;
uint32_t requested_vote_range_upper_bound = p.timestamp;

bool time_range_interference = fsi.last_vote_range_lower_bound < requested_vote_range_upper_bound && requested_vote_range_lower_bound < fsi.last_vote_range_upper_bound;

//my last vote was on (t9, t10_1], I'm asked to vote on t10 : t9 < t10 && t9 < t10_1; //time_range_interference == true, correct
//my last vote was on (t9, t10_1], I'm asked to vote on t11 : t9 < t11 && t10 < t10_1; //time_range_interference == false, correct
//my last vote was on (t7, t9], I'm asked to vote on t10 : t7 < t10 && t9 < t9; //time_range_interference == false, correct

bool enough_for_strong_vote = false;

if (!time_range_interference || extends(p, fork_db.get_block_by_id(fsi.last_vote_block_ref)) enough_for_strong_vote = true;
fsi.is_last_vote_strong = enough_for_strong_vote;

//fsi.is_last_vote_strong = enough_for_strong_vote;
fsi.last_vote_block_ref = p.block_id; //v_height

if (b1.timestamp > fork_db.get_block_by_id(fsi.locked_block_ref).timestamp) fsi.locked_block_ref = b1.block_id; //commit phase on b1
fsi.last_vote_range_lower_bound = new_vote_range_lower_bound;
fsi.last_vote_range_upper_bound = new_vote_range_upper_bound;

fsi.last_vote_range_lower_bound = requested_vote_range_lower_bound;
fsi.last_vote_range_upper_bound = requested_vote_range_upper_bound;

if (enough_for_strong_vote) return VoteDecision::StrongVote;
else return VoteDecision::WeakVote;

}
else return VoteDecision::NoVote;
}
Expand All @@ -282,26 +344,30 @@ void on_signed_block_received(signed_block sb){
on_proposal_received(p, previous);
}

void on_proposal_received(hs_proposal p, block_handle& bc){
void on_proposal_received(signed_block_ptr new_block, block_handle& parent){

//relevant to all nodes
if (p.last_qc_block_height > bc.bhs.last_qc_block_height) {
block_handle found = fork_db.get_block_by_height(p.block_id, p.last_qc_block_height);
if (new_block.last_qc_block_height > parent.bhs.last_qc_block_height) {
block_handle found = fork_db.get_block_by_height(new_block.block_id, new_block.last_qc_block_height);
//verify qc is present and if the qc is valid with respect to the found block, throw exception otherwise

found->valid_qc = new_block.block_extension.qc;
}

[...] //abstracted, relay proposal to other nodes

core new_core = bc.bhs.core.next(p.last_qc_block_height, p.is_last_qc_strong, ...); //f1
//todo : f2
[...] // add to fork db + update block_header_state.core

assembled_block_input data = [...] //construct from new_block;

block_header_state new_block_header_state = parent.bhs.next(data); //f1 & f2

block_handle new_block_handle = add_to_fork_db(parent, new_block_header_state);

bls_public_key[] my_finalizers = [...] //abstracted, must return the public keys of my finalizers that are also active in the current finalizer policy
//only relevant if I have at least one finalizer
if (my_finalizers.size()>0) {
for (auto f : my_finalizers){
finalizer_safety_information& fsi = get_finalizer_info(f);
vote_decision vd = decide_vote(p, fsi, bc); //changes fsi unless NoVote
vote_decision vd = decide_vote(fsi, new_block_handle); //changes fsi unless NoVote
if (vd == VoteDecision::StrongVote || vd == VoteDecision::WeakVote){
save_finalizer_info(f, fsi); //save finalizer info to prevent double-voting
hs_vote_message msg = [...] //create + broadcast vote message
Expand All @@ -312,14 +378,20 @@ void on_proposal_received(hs_proposal p, block_handle& bc){

//when a node receives a vote on a proposal
void on_vote_received(hs_vote_message v){
//check for duplicate or invalid vote, return in either case
//abstracted [...]

//[...] check for duplicate or invalid vote, return in either case

block_handle& bc = fork_db.get_block_by_id(v.block_id);

[...] //abstracted, relay vote to other nodes

am_i_leader = [...] //abstracted, must return true if I am the leader, false otherwise

if(!am_i_leader) return;
//only leader need to take action on votes

//only leader need to take further action on votes
update_pending_qc(v, bc); //update qc for this proposal

}

hs_proposal[] get_qc_chain(hs_proposal p){
Expand All @@ -333,14 +405,21 @@ hs_proposal[] get_qc_chain(hs_proposal p){
//main algorithm entry point. This replaces on_beat() / create_proposal(), and it is now unified with existing systems
{
block_handle head = fork_db.get_head_block();

[...] //if a new finalizer or proposer policy is needed, add it as new_finalizer_policy, new_proposer_policy

[...] //abstracted, create block header


auto found = fork_db.get_block_with_latest_qc(head);
if (head.bhs.is_needed(found.get_best_qc()) {
//insert block extension if a new qc was created
block_extensions.push(construct_hotstuff_block_extension(found.get_best_qc()));
}
header_extensions.push(construct_hotstuff_header_extension(found.get_best_qc()));
header_extensions.push(construct_hotstuff_header_extension(found.get_best_qc(), new_finalizer_policy, new_proposer_policy));
[...] //abstracted, complete block


[...] //abstracted, sign block header
[...] //broadcast signed_block. The signed_block is processed by the on_signed_block_received handler by other nodes on the network
}
Expand Down

0 comments on commit bb6e688

Please sign in to comment.