支持点对网

switch/src/external_route/mod.rs

@@ -0,0 +1,24 @@
+use std::net::Ipv4Addr;
+
+// 目标ip，子网掩码，网关
+
+pub struct ExternalRoute {
+    route_table: Vec<(u32, u32, Ipv4Addr)>,
+}
+
+impl ExternalRoute {
+    pub fn new(route_table: Vec<(u32, u32, Ipv4Addr)>) -> Self {
+        Self {
+            route_table
+        }
+    }
+    pub fn route(&self, ip: &Ipv4Addr) -> Option<Ipv4Addr> {
+        let ip = u32::from_be_bytes(ip.octets());
+        for (dest, mask, gateway) in &self.route_table {
+            if *mask & ip == *mask & *dest {
+                return Some(*gateway);
+            }
+        }
+        None
+    }
+}