Improve UAPI error handler

Replace the fixed count-based error handler
with a duration-based mechanism which is
configurable with FeatureInterfaceHealth.

Signed-off-by: Lukas Pukenis <lukas.pukenis@nordsec.com>

Author: LukasPukenis

.unreleased/LLT-6859

@@ -0,0 +1 @@
+Fix critical error handler and make it configurable

crates/telio-model/src/event.rs

@@ -22,7 +22,7 @@ macro_rules! report_event {
 }
 
 /// Error levels. Used for app to decide what to do with `telio` device when error happens.
-#[derive(Clone, Debug, Default, Serialize)]
+#[derive(Clone, Debug, Default, Serialize, Eq, PartialEq)]
 #[serde(rename_all = "lowercase")]
 pub enum ErrorLevel {
     /// The error level is critical (highest priority)
@@ -37,7 +37,7 @@ pub enum ErrorLevel {
 }
 
 /// Error code. Common error code representation (for statistics).
-#[derive(Clone, Debug, Default, Serialize)]
+#[derive(Clone, Debug, Default, Serialize, Eq, PartialEq)]
 #[serde(rename_all = "lowercase")]
 pub enum ErrorCode {
     /// There is no error in the execution

crates/telio-model/src/features.rs

@@ -102,6 +102,9 @@ pub struct FeatureWireguard {
     /// Configurable wireguard polling period
     #[serde(default)]
     pub polling: FeaturePolling,
+    /// Configurable wireguard interface health monitor
+    #[serde(default)]
+    pub interface_health: FeatureInterfaceHealth,
     /// Configurable up/down behavior of WireGuard-NT adapter. See RFC LLT-0089 for details
     #[serde(default)]
     pub enable_dynamic_wg_nt_control: bool,
@@ -148,6 +151,23 @@ pub struct FeaturePersistentKeepalive {
     pub stun: Option<u32>,
 }
 
+/// Configurable interface health monitor
+#[derive(Copy, Clone, Debug, PartialEq, Eq, Serialize, Deserialize, SmartDefault)]
+#[serde(default)]
+#[cfg_attr(test, derive(proptest_derive::Arbitrary))]
+pub struct FeatureInterfaceHealth {
+    /// Minimum time separation between UAPI failures required to classify
+    /// a failure as non-transient. (in seconds) [default 10s]
+    #[default(10)]
+    pub transient_failure_separation_threshold: u32,
+
+    /// Maximum poll gap before treating libtelio as suspended for transient failure filtering
+    /// for WireguardNT. Recommended to be slightly higher than twice the FeaturePolling.wireguard_polling_period
+    /// (in seconds) [default 5s]
+    #[default(5)]
+    pub uapi_poll_suspension_threshold: u32,
+}
+
 /// Configurable Wireguard polling period
 #[derive(Clone, Debug, PartialEq, Eq, Serialize, Deserialize, SmartDefault)]
 #[serde(default)]
@@ -698,6 +718,10 @@ mod tests {
                     "wireguard_polling_period": 1000,
                     "wireguard_polling_period_after_state_change": 50
                 },
+                "interface_health": {
+                    "transient_failure_separation_threshold": 44,
+                    "uapi_poll_suspension_threshold": 55
+                },
                 "enable_dynamic_wg_nt_control": true,
                 "skt_buffer_size": 123456,
                 "inter_thread_channel_size": 123456,
@@ -801,6 +825,10 @@ mod tests {
                             wireguard_polling_period: 1000,
                             wireguard_polling_period_after_state_change: 50
                         },
+                        interface_health: FeatureInterfaceHealth {
+                            transient_failure_separation_threshold: 44,
+                            uapi_poll_suspension_threshold: 55
+                        },
                         enable_dynamic_wg_nt_control: true,
                         skt_buffer_size: Some(123456),
                         inter_thread_channel_size: Some(123456),