equihash: Add Rust API for Tromp solver

components/equihash/src/blake2b.rs

@@ -3,14 +3,14 @@
 // file COPYING or https://www.opensource.org/licenses/mit-license.php .
 
 use blake2b_simd::{State, PERSONALBYTES};
-use libc::{c_uchar, size_t};
+
 use std::ptr;
 use std::slice;
 
 #[no_mangle]
 pub extern "C" fn blake2b_init(
-    output_len: size_t,
-    personalization: *const [c_uchar; PERSONALBYTES],
+    output_len: usize,
+    personalization: *const [u8; PERSONALBYTES],
 ) -> *mut State {
     let personalization = unsafe { personalization.as_ref().unwrap() };
 
@@ -37,15 +37,15 @@ pub extern "C" fn blake2b_free(state: *mut State) {
 }
 
 #[no_mangle]
-pub extern "C" fn blake2b_update(state: *mut State, input: *const c_uchar, input_len: size_t) {
+pub extern "C" fn blake2b_update(state: *mut State, input: *const u8, input_len: usize) {
     let state = unsafe { state.as_mut().unwrap() };
     let input = unsafe { slice::from_raw_parts(input, input_len) };
 
     state.update(input);
 }
 
 #[no_mangle]
-pub extern "C" fn blake2b_finalize(state: *mut State, output: *mut c_uchar, output_len: size_t) {
+pub extern "C" fn blake2b_finalize(state: *mut State, output: *mut u8, output_len: usize) {
     let state = unsafe { state.as_mut().unwrap() };
     let output = unsafe { slice::from_raw_parts_mut(output, output_len) };
 

components/equihash/src/lib.rs

@@ -26,3 +26,6 @@ mod verify;
 mod test_vectors;
 
 pub use verify::{is_valid_solution, Error};
+
+mod blake2b;
+pub mod tromp;

components/equihash/src/tromp.rs

@@ -0,0 +1,109 @@
+use std::marker::{PhantomData, PhantomPinned};
+use std::slice;
+
+use blake2b_simd::State;
+
+use crate::{blake2b, verify};
+
+#[repr(C)]
+struct CEqui {
+    _f: [u8; 0],
+    _m: PhantomData<(*mut u8, PhantomPinned)>,
+}
+
+#[link(name = "equitromp")]
+extern "C" {
+    #[allow(improper_ctypes)]
+    fn equi_new(
+        n_threads: u32,
+        blake2b_clone: extern "C" fn(state: *const State) -> *mut State,
+        blake2b_free: extern "C" fn(state: *mut State),
+        blake2b_update: extern "C" fn(state: *mut State, input: *const u8, input_len: usize),
+        blake2b_finalize: extern "C" fn(state: *mut State, output: *mut u8, output_len: usize),
+    ) -> *mut CEqui;
+    fn equi_free(eq: *mut CEqui);
+    #[allow(improper_ctypes)]
+    fn equi_setstate(eq: *mut CEqui, ctx: *const State);
+    fn equi_clearslots(eq: *mut CEqui);
+    fn equi_digit0(eq: *mut CEqui, id: u32);
+    fn equi_digitodd(eq: *mut CEqui, r: u32, id: u32);
+    fn equi_digiteven(eq: *mut CEqui, r: u32, id: u32);
+    fn equi_digitK(eq: *mut CEqui, id: u32);
+    fn equi_nsols(eq: *const CEqui) -> usize;
+    fn equi_sols(eq: *const CEqui) -> *const *const u32;
+}
+
+unsafe fn worker(p: verify::Params, curr_state: &State) -> Vec<Vec<u32>> {
+    // Create solver and initialize it.
+    let eq = equi_new(
+        1,
+        blake2b::blake2b_clone,
+        blake2b::blake2b_free,
+        blake2b::blake2b_update,
+        blake2b::blake2b_finalize,
+    );
+    equi_setstate(eq, curr_state);
+
+    // Initialization done, start algo driver.
+    equi_digit0(eq, 0);
+    equi_clearslots(eq);
+    for r in 1..p.k {
+        if (r & 1) != 0 {
+            equi_digitodd(eq, r, 0)
+        } else {
+            equi_digiteven(eq, r, 0)
+        };
+        equi_clearslots(eq);
+    }
+    equi_digitK(eq, 0);
+
+    let solutions = {
+        let nsols = equi_nsols(eq);
+        let sols = equi_sols(eq);
+        let solutions = slice::from_raw_parts(sols, nsols);
+        let solution_len = 1 << p.k;
+
+        solutions
+            .iter()
+            .map(|solution| slice::from_raw_parts(*solution, solution_len).to_vec())
+            .collect::<Vec<_>>()
+    };
+
+    equi_free(eq);
+
+    solutions
+}
+
+pub fn solve_200_9(input: &[u8], nonce: &[u8]) -> Vec<Vec<u32>> {
+    let p = verify::Params::new(200, 9).expect("should be valid");
+    let mut state = verify::initialise_state(p.n, p.k, p.hash_output());
+    state.update(input);
+    state.update(nonce);
+
+    unsafe { worker(p, &state) }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::solve_200_9;
+
+    #[test]
+    fn run_solver() {
+        let input = b"Equihash is an asymmetric PoW based on the Generalised Birthday problem.";
+        let nonce = [
+            1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+            0, 0, 0,
+        ];
+
+        let solutions = solve_200_9(input, &nonce);
+
+        if solutions.is_empty() {
+            println!("Found no solutions");
+        } else {
+            println!("Found {} solutions:", solutions.len());
+            for solution in solutions {
+                println!("- {:?}", solution);
+            }
+        }
+    }
+}

components/equihash/src/verify.rs

@@ -21,7 +21,7 @@ struct Node {
 }
 
 impl Params {
-    fn new(n: u32, k: u32) -> Result<Self, Error> {
+    pub(crate) fn new(n: u32, k: u32) -> Result<Self, Error> {
         // We place the following requirements on the parameters:
         // - n is a multiple of 8, so the hash output has an exact byte length.
         // - k >= 3 so the encoded solutions have an exact byte length.
@@ -36,7 +36,7 @@ impl Params {
     fn indices_per_hash_output(&self) -> u32 {
         512 / self.n
     }
-    fn hash_output(&self) -> u8 {
+    pub(crate) fn hash_output(&self) -> u8 {
         (self.indices_per_hash_output() * self.n / 8) as u8
     }
     fn collision_bit_length(&self) -> usize {
@@ -148,7 +148,7 @@ impl fmt::Display for Kind {
     }
 }
 
-fn initialise_state(n: u32, k: u32, digest_len: u8) -> Blake2bState {
+pub(crate) fn initialise_state(n: u32, k: u32, digest_len: u8) -> Blake2bState {
     let mut personalization: Vec<u8> = Vec::from("ZcashPoW");
     personalization.write_u32::<LittleEndian>(n).unwrap();
     personalization.write_u32::<LittleEndian>(k).unwrap();

components/equihash/tromp/equi_miner.c

@@ -268,6 +268,9 @@ typedef struct equi equi;
     memset(eq->nslots, 0, NBUCKETS * sizeof(au32)); // only nslots[0] needs zeroing
     eq->nsols = 0;
   }
+  void equi_clearslots(equi *eq) {
+    eq->xfull = eq->bfull = eq->hfull = 0;
+  }
   u32 getslot(equi *eq, const u32 r, const u32 bucketi) {
 #ifdef EQUIHASH_TROMP_ATOMIC
     return std::atomic_fetch_add_explicit(&eq->nslots[r&1][bucketi], 1U, std::memory_order_relaxed);
@@ -637,6 +640,13 @@ nc++,       candidate(eq, tree_from_bid(bucketid, s0, s1));
 //printf(" %d candidates ", nc);
   }
 
+  size_t equi_nsols(const equi *eq) {
+    return eq->nsols;
+  }
+  proof *equi_sols(const equi *eq) {
+    return eq->sols;
+  }
+
 typedef struct {
   u32 id;
   pthread_t thread;