outbound_session: fix bug in Slot white_count calculations

settings.white_count was 90 by default (a percentage) but was being
treated as an absolute value in outbound session.

we fix this and simplify the types to avoid excessive conversions.

src/net/session/outbound_session.rs

@@ -225,11 +225,11 @@ impl Slot {
     /// connections. A network that purely favors uptime over unreliable
     /// connections may be vulnerable to sybil by attackers with good uptime.
     async fn fetch_addrs_with_preference(&self, preference: SlotPreference) -> Vec<(Url, u64)> {
-        let slot = self.slot;
+        let slot = self.slot as usize;
         let settings = self.p2p().settings();
         let hosts = &self.p2p().hosts().container;
 
-        let white_count = settings.white_connect_count;
+        let white_count = (settings.white_connect_percent * settings.outbound_connections) / 100;
         let gold_count = settings.gold_connect_count;
 
         let transports = &settings.allowed_transports;

src/net/settings.rs

@@ -69,9 +69,9 @@ pub struct Settings {
     /// Pause interval within greylist refinery process
     pub greylist_refinery_interval: u64,
     /// Percent of connections to come from the whitelist
-    pub white_connect_count: u32,
+    pub white_connect_percent: usize,
     /// Number of goldlist connections
-    pub gold_connect_count: u32,
+    pub gold_connect_count: usize,
     /// Number of seconds with no connections after which refinery
     /// process is paused.
     pub time_with_no_connections: u64,
@@ -104,7 +104,7 @@ impl Default for Settings {
             outbound_peer_discovery_attempt_time: 5,
             hostlist: "/dev/null".to_string(),
             greylist_refinery_interval: 15,
-            white_connect_count: 90,
+            white_connect_percent: 90,
             gold_connect_count: 2,
             time_with_no_connections: 30,
             blacklist: vec![],
@@ -200,11 +200,11 @@ pub struct SettingsOpt {
 
     /// Number of whitelist connections
     #[structopt(skip)]
-    pub white_connect_count: Option<u32>,
+    pub white_connect_percent: Option<usize>,
 
     /// Number of goldlist connections
     #[structopt(skip)]
-    pub gold_connect_count: Option<u32>,
+    pub gold_connect_count: Option<usize>,
 
     /// Number of seconds with no connections after which refinery
     /// process is paused.
@@ -253,7 +253,7 @@ impl From<SettingsOpt> for Settings {
             greylist_refinery_interval: opt
                 .greylist_refinery_interval
                 .unwrap_or(def.greylist_refinery_interval),
-            white_connect_count: opt.white_connect_count.unwrap_or(def.white_connect_count),
+            white_connect_percent: opt.white_connect_percent.unwrap_or(def.white_connect_percent),
             gold_connect_count: opt.gold_connect_count.unwrap_or(def.gold_connect_count),
             time_with_no_connections: opt
                 .time_with_no_connections