feat: initialize TeachLink project structure with core modules and error definitions

contracts/teachlink/src/atomic_swap.rs

@@ -127,6 +127,14 @@ impl AtomicSwapManager {
                 return Err(BridgeError::InvalidInput);
             }
 
+            // Temporal Validation
+            crate::validation::TimeValidator::validate_global_bounds(env, env.ledger().timestamp())
+                .map_err(|_| BridgeError::InvalidTimestamp)?;
+
+            let future_timelock = env.ledger().timestamp().saturating_add(timelock);
+            crate::validation::TimeValidator::validate_operational_bounds(env, future_timelock)
+                .map_err(|_| BridgeError::InvalidTimestamp)?;
+
             let mut swap_counter: u64 = env.storage().instance().get(&SWAP_COUNTER).unwrap_or(0u64);
             swap_counter += 1;
 

contracts/teachlink/src/audit.rs

@@ -82,6 +82,10 @@ impl AuditManager {
 
         audit_counter += 1;
 
+        // Validate timestamp sanity
+        crate::validation::TimeValidator::validate_global_bounds(env, env.ledger().timestamp())
+            .map_err(|_| BridgeError::InvalidTimestamp)?;
+
         // Create audit record
         let record = AuditRecord {
             record_id: audit_counter,

contracts/teachlink/src/errors.rs

@@ -80,4 +80,4 @@ pub enum BridgeError {
     StorageError = 143,
     NotInitialized = 144,
     IncompatibleInterfaceVersion = 145,
-    InvalidInterfaceVersionRange
+    InvalidInterfaceVersionRange

contracts/teachlink/src/timestamp_tests.rs

@@ -0,0 +1,89 @@
+#[cfg(test)]
+mod tests {
+    use crate::validation::{config, TimeValidator, ValidationError};
+    use soroban_sdk::{testutils::Ledger, Env};
+
+    fn set_ledger_time(env: &Env, timestamp: u64) {
+        env.ledger().with_mut(|li| {
+            li.timestamp = timestamp;
+        });
+    }
+
+    #[test]
+    fn test_global_bounds_pass() {
+        let env = Env::default();
+        let now = 1_000_000;
+        set_ledger_time(&env, now);
+
+        assert!(TimeValidator::validate_global_bounds(&env, now).is_ok());
+        assert!(TimeValidator::validate_global_bounds(&env, now + 3600).is_ok());
+        assert!(TimeValidator::validate_global_bounds(&env, now - 3600).is_ok());
+    }
+
+    #[test]
+    fn test_global_bounds_fail_future() {
+        let env = Env::default();
+        let now = 1_000_000;
+        set_ledger_time(&env, now);
+
+        let way_future = now + config::MAX_TIMEOUT_SECONDS + 1;
+        assert_eq!(
+            TimeValidator::validate_global_bounds(&env, way_future),
+            Err(ValidationError::InvalidTimestamp)
+        );
+    }
+
+    #[test]
+    fn test_global_bounds_fail_past() {
+        let env = Env::default();
+        let now = config::MAX_TIMEOUT_SECONDS + 1_000_000;
+        set_ledger_time(&env, now);
+
+        let way_past = 0;
+        assert_eq!(
+            TimeValidator::validate_global_bounds(&env, way_past),
+            Err(ValidationError::InvalidTimestamp)
+        );
+    }
+
+    #[test]
+    fn test_operational_bounds() {
+        let env = Env::default();
+        let now = 10_000_000;
+        set_ledger_time(&env, now);
+
+        // 90 days = 7,776,000 seconds
+        assert!(TimeValidator::validate_operational_bounds(&env, now + 7_000_000).is_ok());
+
+        assert_eq!(
+            TimeValidator::validate_operational_bounds(&env, now + 8_000_000),
+            Err(ValidationError::InvalidTimestamp)
+        );
+    }
+
+    #[test]
+    fn test_monotonicity() {
+        assert!(TimeValidator::check_monotonic(100, 101).is_ok());
+        assert!(TimeValidator::check_monotonic(100, 100).is_ok());
+        assert_eq!(
+            TimeValidator::check_monotonic(101, 100),
+            Err(ValidationError::TimestampNotMonotonic)
+        );
+    }
+
+    #[test]
+    fn test_skew_tolerance() {
+        let env = Env::default();
+        let now = 1_000_000;
+        set_ledger_time(&env, now);
+
+        // 15 minutes = 900 seconds
+        assert!(TimeValidator::validate_skew(&env, now + 800).is_ok());
+        assert!(TimeValidator::validate_skew(&env, now - 800).is_ok());
+
+        assert_eq!(
+            TimeValidator::validate_skew(&env, now + 1000),
+            Err(ValidationError::TimestampSkewExceeded)
+        );
+    }
+}

contracts/teachlink/src/validation.rs

@@ -58,8 +58,9 @@ pub enum ValidationError {
     DuplicateSigners,
     InvalidBytesLength,
     InvalidCrossChainData,
-    SelfInteractionNotAllowed,
-    WhitespaceOnlyString,
+    InvalidTimestamp,
+    TimestampNotMonotonic,
+    TimestampSkewExceeded,
 }
 
 /// Result type for validation operations
@@ -335,6 +336,74 @@ impl BytesValidator {
     }
 }
 
+/// Time validation utilities
+pub struct TimeValidator;
+
+impl TimeValidator {
+    /// Validates if a timestamp is within the global sanity bound (10 years)
+    pub fn validate_global_bounds(env: &Env, timestamp: u64) -> ValidationResult<()> {
+        let current_time = env.ledger().timestamp();
+
+        // Prevent far-future timestamps
+        if timestamp > current_time + config::MAX_TIMEOUT_SECONDS {
+            return Err(ValidationError::InvalidTimestamp);
+        }
+
+        // Prevent far-past timestamps (saturating sub for safety)
+        if timestamp < current_time.saturating_sub(config::MAX_TIMEOUT_SECONDS) {
+            return Err(ValidationError::InvalidTimestamp);
+        }
+
+        Ok(())
+    }
+
+    /// Validates if a timestamp is within operational bounds (90 days)
+    pub fn validate_operational_bounds(env: &Env, timestamp: u64) -> ValidationResult<()> {
+        let current_time = env.ledger().timestamp();
+
+        if timestamp > current_time + config::MAX_OPERATIONAL_TIMEOUT {
+            return Err(ValidationError::InvalidTimestamp);
+        }
+
+        if timestamp < current_time.saturating_sub(config::MAX_OPERATIONAL_TIMEOUT) {
+            return Err(ValidationError::InvalidTimestamp);
+        }
+
+        Ok(())
+    }
+
+    /// Ensures that time has progressed monotonically
+    pub fn check_monotonic(last_timestamp: u64, current_timestamp: u64) -> ValidationResult<()> {
+        if current_timestamp < last_timestamp {
+            return Err(ValidationError::TimestampNotMonotonic);
+        }
+        Ok(())
+    }
+
+    /// Validates a timestamp with network skew tolerance (15 minutes)
+    pub fn validate_skew(env: &Env, external_timestamp: u64) -> ValidationResult<()> {
+        let current_time = env.ledger().timestamp();
+        let diff = if external_timestamp > current_time {
+            external_timestamp - current_time
+        } else {
+            current_time - external_timestamp
+        };
+
+        if diff > config::MAX_TIME_SKEW {
+            return Err(ValidationError::TimestampSkewExceeded);
+        }
+        Ok(())
+    }
+
+    /// Validates that a deadline is actually in the future
+    pub fn validate_is_future(env: &Env, deadline: u64) -> ValidationResult<()> {
+        if deadline <= env.ledger().timestamp() {
+            return Err(ValidationError::InvalidTimestamp);
+        }
+        Ok(())
+    }
+}
+
 /// Cross-chain data validation utilities
 pub struct CrossChainValidator;
 
@@ -415,10 +484,23 @@ impl EscrowValidator {
         }
 
         // Validate time constraints
+        if let Some(release) = release_time {
+            TimeValidator::validate_global_bounds(env, release)
+                .map_err(|_| EscrowError::InvalidTimestamp)?;
+            TimeValidator::validate_is_future(env, release)
+                .map_err(|_| EscrowError::InvalidTimestamp)?;
+        }
+
+        if let Some(refund) = refund_time {
+            TimeValidator::validate_global_bounds(env, refund)
+                .map_err(|_| EscrowError::InvalidTimestamp)?;
+            TimeValidator::validate_is_future(env, refund)
+                .map_err(|_| EscrowError::InvalidTimestamp)?;
+        }
+
         if let (Some(release), Some(refund)) = (release_time, refund_time) {
-            if refund <= release {
-                return Err(EscrowError::RefundTimeMustBeAfterReleaseTime);
-            }
+            TimeValidator::check_monotonic(release, refund)
+                .map_err(|_| EscrowError::RefundTimeMustBeAfterReleaseTime)?;
         }
 
         Ok(())
@@ -606,6 +688,10 @@ impl BridgeValidator {
         InputSanitizer::sanitize_destination_address(destination_address)
             .map_err(|_| crate::errors::BridgeError::InvalidInput)?;
 
+        // Validate current timestamp sanity
+        TimeValidator::validate_global_bounds(env, env.ledger().timestamp())
+            .map_err(|_| crate::errors::BridgeError::InvalidTimestamp)?;
+
         Ok(())
     }
 
@@ -631,6 +717,10 @@ impl BridgeValidator {
         )
         .map_err(|_| crate::errors::BridgeError::InvalidInput)?;
 
+        // Validate cross-chain message timestamp sanity (use current ledger time)
+        TimeValidator::validate_global_bounds(env, env.ledger().timestamp())
+            .map_err(|_| crate::errors::BridgeError::InvalidTimestamp)?;
+
         Ok(())
     }
 }