kvault_interface/
discriminators.rs

1//! Anchor-compatible instruction discriminators for Kvault.
2//!
3//! Each instruction is identified by the first 8 bytes of
4//! `SHA-256("global:<snake_case_name>")`. The constants are computed at
5//! compile time via a const-compatible SHA-256 implementation.
6
7use sha2::{Digest, Sha256};
8
9/// Compute the 8-byte Anchor discriminator for a given instruction name.
10///
11/// Uses the convention: `sha256("global:<snake_case_name>")[..8]`.
12pub fn compute_discriminator(name: &str) -> [u8; 8] {
13    let mut hasher = Sha256::new();
14    hasher.update(format!("global:{name}"));
15    let hash = hasher.finalize();
16    let mut disc = [0u8; 8];
17    disc.copy_from_slice(&hash[..8]);
18    disc
19}
20
21macro_rules! disc {
22    ($(#[$meta:meta])* $name:ident, $ix:expr) => {
23        $(#[$meta])*
24        pub static $name: [u8; 8] = {
25            const PREIMAGE: &[u8] = concat!("global:", $ix).as_bytes();
26            sha256_first8(PREIMAGE)
27        };
28    };
29}
30
31const SHA256_K: [u32; 64] = [
32    0x428a2f98, 0x71374491, 0xb5c0fbcf, 0xe9b5dba5, 0x3956c25b, 0x59f111f1, 0x923f82a4, 0xab1c5ed5,
33    0xd807aa98, 0x12835b01, 0x243185be, 0x550c7dc3, 0x72be5d74, 0x80deb1fe, 0x9bdc06a7, 0xc19bf174,
34    0xe49b69c1, 0xefbe4786, 0x0fc19dc6, 0x240ca1cc, 0x2de92c6f, 0x4a7484aa, 0x5cb0a9dc, 0x76f988da,
35    0x983e5152, 0xa831c66d, 0xb00327c8, 0xbf597fc7, 0xc6e00bf3, 0xd5a79147, 0x06ca6351, 0x14292967,
36    0x27b70a85, 0x2e1b2138, 0x4d2c6dfc, 0x53380d13, 0x650a7354, 0x766a0abb, 0x81c2c92e, 0x92722c85,
37    0xa2bfe8a1, 0xa81a664b, 0xc24b8b70, 0xc76c51a3, 0xd192e819, 0xd6990624, 0xf40e3585, 0x106aa070,
38    0x19a4c116, 0x1e376c08, 0x2748774c, 0x34b0bcb5, 0x391c0cb3, 0x4ed8aa4a, 0x5b9cca4f, 0x682e6ff3,
39    0x748f82ee, 0x78a5636f, 0x84c87814, 0x8cc70208, 0x90befffa, 0xa4506ceb, 0xbef9a3f7, 0xc67178f2,
40];
41
42/// Compress a single 64-byte block into the state, returning the new state.
43const fn compress_block(h: [u32; 8], block: [u8; 64]) -> [u32; 8] {
44    let mut w = [0u32; 64];
45    let mut i = 0;
46    while i < 16 {
47        w[i] = ((block[i * 4] as u32) << 24)
48            | ((block[i * 4 + 1] as u32) << 16)
49            | ((block[i * 4 + 2] as u32) << 8)
50            | (block[i * 4 + 3] as u32);
51        i += 1;
52    }
53    i = 16;
54    while i < 64 {
55        let s0 = w[i - 15].rotate_right(7) ^ w[i - 15].rotate_right(18) ^ (w[i - 15] >> 3);
56        let s1 = w[i - 2].rotate_right(17) ^ w[i - 2].rotate_right(19) ^ (w[i - 2] >> 10);
57        w[i] = w[i - 16]
58            .wrapping_add(s0)
59            .wrapping_add(w[i - 7])
60            .wrapping_add(s1);
61        i += 1;
62    }
63
64    let (mut a, mut b, mut c, mut d, mut e, mut f, mut g, mut hh) =
65        (h[0], h[1], h[2], h[3], h[4], h[5], h[6], h[7]);
66
67    i = 0;
68    while i < 64 {
69        let s1 = e.rotate_right(6) ^ e.rotate_right(11) ^ e.rotate_right(25);
70        let ch = (e & f) ^ ((!e) & g);
71        let temp1 = hh
72            .wrapping_add(s1)
73            .wrapping_add(ch)
74            .wrapping_add(SHA256_K[i])
75            .wrapping_add(w[i]);
76        let s0 = a.rotate_right(2) ^ a.rotate_right(13) ^ a.rotate_right(22);
77        let maj = (a & b) ^ (a & c) ^ (b & c);
78        let temp2 = s0.wrapping_add(maj);
79
80        hh = g;
81        g = f;
82        f = e;
83        e = d.wrapping_add(temp1);
84        d = c;
85        c = b;
86        b = a;
87        a = temp1.wrapping_add(temp2);
88        i += 1;
89    }
90
91    [
92        h[0].wrapping_add(a),
93        h[1].wrapping_add(b),
94        h[2].wrapping_add(c),
95        h[3].wrapping_add(d),
96        h[4].wrapping_add(e),
97        h[5].wrapping_add(f),
98        h[6].wrapping_add(g),
99        h[7].wrapping_add(hh),
100    ]
101}
102
103/// Const-compatible SHA-256 returning only the first 8 bytes.
104/// Supports messages up to 119 bytes (two 64-byte blocks).
105pub const fn sha256_first8(msg: &[u8]) -> [u8; 8] {
106    let h: [u32; 8] = [
107        0x6a09e667, 0xbb67ae85, 0x3c6ef372, 0xa54ff53a, 0x510e527f, 0x9b05688c, 0x1f83d9ab,
108        0x5be0cd19,
109    ];
110
111    let bit_len = (msg.len() as u64) * 8;
112    let padded_len = if msg.len() + 9 <= 64 { 64 } else { 128 };
113
114    let mut padded = [0u8; 128];
115    let mut i = 0;
116    while i < msg.len() {
117        padded[i] = msg[i];
118        i += 1;
119    }
120    padded[msg.len()] = 0x80;
121    padded[padded_len - 8] = (bit_len >> 56) as u8;
122    padded[padded_len - 7] = (bit_len >> 48) as u8;
123    padded[padded_len - 6] = (bit_len >> 40) as u8;
124    padded[padded_len - 5] = (bit_len >> 32) as u8;
125    padded[padded_len - 4] = (bit_len >> 24) as u8;
126    padded[padded_len - 3] = (bit_len >> 16) as u8;
127    padded[padded_len - 2] = (bit_len >> 8) as u8;
128    padded[padded_len - 1] = bit_len as u8;
129
130    // First block
131    let mut block0 = [0u8; 64];
132    i = 0;
133    while i < 64 {
134        block0[i] = padded[i];
135        i += 1;
136    }
137    let h = compress_block(h, block0);
138
139    // Second block (if needed)
140    let h = if padded_len > 64 {
141        let mut block1 = [0u8; 64];
142        i = 0;
143        while i < 64 {
144            block1[i] = padded[64 + i];
145            i += 1;
146        }
147        compress_block(h, block1)
148    } else {
149        h
150    };
151
152    [
153        (h[0] >> 24) as u8,
154        (h[0] >> 16) as u8,
155        (h[0] >> 8) as u8,
156        h[0] as u8,
157        (h[1] >> 24) as u8,
158        (h[1] >> 16) as u8,
159        (h[1] >> 8) as u8,
160        h[1] as u8,
161    ]
162}
163
164disc!(
165    /// Discriminator for the `deposit` instruction.
166    DEPOSIT,
167    "deposit"
168);
169disc!(
170    /// Discriminator for the `buy` instruction.
171    BUY,
172    "buy"
173);
174
175disc!(
176    /// Discriminator for the `withdraw` instruction.
177    WITHDRAW,
178    "withdraw"
179);
180disc!(
181    /// Discriminator for the `sell` instruction.
182    SELL,
183    "sell"
184);
185disc!(
186    /// Discriminator for the `withdraw_from_available` instruction.
187    WITHDRAW_FROM_AVAILABLE,
188    "withdraw_from_available"
189);
190
191disc!(
192    /// Discriminator for the `invest` instruction.
193    INVEST,
194    "invest"
195);
196disc!(
197    /// Discriminator for the `invest_with_max_amount` instruction.
198    INVEST_WITH_MAX_AMOUNT,
199    "invest_with_max_amount"
200);
201
202disc!(
203    /// Discriminator for the `redeem_in_kind` instruction.
204    REDEEM_IN_KIND,
205    "redeem_in_kind"
206);
207
208/// Known Kvault instruction types, identified by their 8-byte discriminator.
209#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
210#[non_exhaustive]
211pub enum KvaultInstruction {
212    /// Deposit tokens into a vault and receive shares.
213    Deposit,
214    /// Buy vault shares (same accounts as deposit, different discriminator).
215    Buy,
216    /// Withdraw from available and invested liquidity via a reserve.
217    Withdraw,
218    /// Sell vault shares (same accounts as withdraw, different discriminator).
219    Sell,
220    /// Withdraw exclusively from the vault's available (uninvested) balance.
221    WithdrawFromAvailable,
222    /// Deploy available vault liquidity into a Klend reserve.
223    Invest,
224    /// Deploy at most a caller-provided amount of available vault liquidity.
225    InvestWithMaxAmount,
226    /// Redeem vault shares for cTokens instead of the underlying token.
227    RedeemInKind,
228}
229
230impl core::fmt::Display for KvaultInstruction {
231    fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
232        write!(f, "{self:?}")
233    }
234}
235
236/// Identify a Kvault instruction from its raw instruction data.
237///
238/// Returns `Some(variant)` if the first 8 bytes match a known discriminator,
239/// `None` otherwise.
240pub fn identify_instruction(data: &[u8]) -> Option<KvaultInstruction> {
241    if data.len() < 8 {
242        return None;
243    }
244    let mut disc = [0u8; 8];
245    disc.copy_from_slice(&data[..8]);
246
247    match disc {
248        d if d == DEPOSIT => Some(KvaultInstruction::Deposit),
249        d if d == BUY => Some(KvaultInstruction::Buy),
250        d if d == WITHDRAW => Some(KvaultInstruction::Withdraw),
251        d if d == SELL => Some(KvaultInstruction::Sell),
252        d if d == WITHDRAW_FROM_AVAILABLE => Some(KvaultInstruction::WithdrawFromAvailable),
253        d if d == INVEST => Some(KvaultInstruction::Invest),
254        d if d == INVEST_WITH_MAX_AMOUNT => Some(KvaultInstruction::InvestWithMaxAmount),
255        d if d == REDEEM_IN_KIND => Some(KvaultInstruction::RedeemInKind),
256        _ => None,
257    }
258}
259
260#[cfg(test)]
261mod tests {
262    use super::*;
263
264    macro_rules! check_disc {
265        ($name:expr, $constant:ident) => {
266            assert_eq!(
267                compute_discriminator($name),
268                $constant,
269                "Discriminator mismatch for {}",
270                $name
271            );
272        };
273    }
274
275    #[test]
276    fn verify_all_discriminators() {
277        check_disc!("deposit", DEPOSIT);
278        check_disc!("buy", BUY);
279        check_disc!("withdraw", WITHDRAW);
280        check_disc!("sell", SELL);
281        check_disc!("withdraw_from_available", WITHDRAW_FROM_AVAILABLE);
282        check_disc!("invest", INVEST);
283        check_disc!("invest_with_max_amount", INVEST_WITH_MAX_AMOUNT);
284        check_disc!("redeem_in_kind", REDEEM_IN_KIND);
285    }
286}
kvault_interface/discriminators.rs

kvault_interface/
discriminators.rs
