feat: alloc 127.0.0.2 ~ 127.0.0.8 to loopback device

Author: Samuka007

kernel/Cargo.toml

@@ -46,7 +46,7 @@ linkme = "=0.3.27"
 num = { version = "=0.4.0", default-features = false }
 num-derive = "=0.3"
 num-traits = { git = "https://git.mirrors.dragonos.org.cn/DragonOS-Community/num-traits.git", rev="1597c1c", default-features = false }
-smoltcp = { version = "=0.11.0", default-features = false, features = ["log", "alloc",  "socket-raw", "socket-udp", "socket-tcp", "socket-icmp", "socket-dhcpv4", "socket-dns", "proto-ipv4", "proto-ipv6"]}
+smoltcp = { version = "=0.11.0", default-features = false, features = ["log", "alloc",  "socket-raw", "socket-udp", "socket-tcp", "socket-icmp", "socket-dhcpv4", "socket-dns", "proto-ipv4", "proto-ipv6", "iface-max-addr-count-8"]}
 system_error = { path = "crates/system_error" }
 unified-init = { path = "crates/unified-init" }
 virtio-drivers = { git = "https://git.mirrors.dragonos.org.cn/DragonOS-Community/virtio-drivers", rev = "f91c807965" }

kernel/src/driver/net/loopback.rs

@@ -264,9 +264,11 @@ impl LoopbackInterface {
             smoltcp::iface::Interface::new(iface_config, &mut driver, Instant::now().into());
         //设置网卡地址为127.0.0.1
         iface.update_ip_addrs(|ip_addrs| {
-            ip_addrs
-                .push(IpCidr::new(IpAddress::v4(127, 0, 0, 1), 8))
-                .unwrap();
+            for i in 1..=8 {
+                ip_addrs
+                    .push(IpCidr::new(IpAddress::v4(127, 0, 0, i), 8))
+                    .expect("Push ipCidr failed: full");
+            }
         });
         let driver = LoopbackDriverWapper(UnsafeCell::new(driver));
         Arc::new(LoopbackInterface {

user/apps/test_lo/src/main.rs

@@ -2,14 +2,16 @@ use std::net::UdpSocket;
 use std::str;
 
 fn main() -> std::io::Result<()> {
-    let socket = UdpSocket::bind("127.0.0.1:34254")?;
-    socket.connect("127.0.0.1:34254")?;
+    let socket = UdpSocket::bind("10.0.2.15:34254")?;
+    socket.connect("127.0.0.2:34255")?;
+
+    let listener = UdpSocket::bind("127.0.0.2:34255")?;
 
     let msg = "Hello, loopback!";
     socket.send(msg.as_bytes())?;
 
     let mut buf = [0; 1024];
-    let (amt, _src) = socket.recv_from(&mut buf)?;
+    let (amt, _src) = listener.recv_from(&mut buf)?;
 
     let received_msg = str::from_utf8(&buf[..amt]).expect("Could not read buffer as UTF-8");