close to finish a tun/smoltcp

client/src/connections/ip_store.rs

@@ -0,0 +1,36 @@
+use lru::LruCache;
+use std::net::Ipv4Addr;
+use std::num::NonZeroUsize;
+
+pub struct FakeIpStore {
+    cache: LruCache<String, Ipv4Addr>,
+    pub rev_cache: LruCache<Ipv4Addr, String>,
+    next_ip: u32,
+}
+
+const START_IP: u32 = 0x64400001; // 100.64.0.1 (IP for Service Networks/Shared Address Space)
+
+impl FakeIpStore {
+    pub fn new() -> Self {
+        Self {
+            cache: LruCache::new(NonZeroUsize::new(2000).unwrap()),
+            rev_cache: LruCache::new(NonZeroUsize::new(2000).unwrap()),
+            next_ip: START_IP,
+        }
+    }
+
+    pub fn get_or_assign(&mut self, host: &str) -> Ipv4Addr {
+        if let Some(&ip) = self.cache.get(host) {
+            return ip;
+        }
+        let ip = Ipv4Addr::from(self.next_ip);
+        self.next_ip += 1;
+        self.cache.put(host.to_string(), ip);
+        self.rev_cache.put(ip, host.to_string());
+        ip
+    }
+
+    pub fn lookup_by_ip(&self, ip: &Ipv4Addr) -> Option<String> {
+        self.rev_cache.peek(ip).cloned()
+    }
+}