Merge pull request #111 from yfblock/ch9

Add the TCP support

os/Cargo.toml

@@ -14,7 +14,7 @@ bitflags = "1.2.1"
 xmas-elf = "0.7.0"
 volatile = "0.3"
 virtio-drivers = { git = "https://github.com/rcore-os/virtio-drivers", rev = "4ee80e5" }
-lose-net-stack = { git = "https://github.com/yfblock/lose-net-stack", rev = "3f467dd" }
+lose-net-stack = { git = "https://github.com/yfblock/lose-net-stack", rev = "db42380" }
 easy-fs = { path = "../easy-fs" }
 embedded-graphics = "0.7.1"
 tinybmp = "0.3.1"

os/Makefile

@@ -86,7 +86,7 @@ run-inner-none: build
 		-device virtio-keyboard-device  \
 		-device virtio-mouse-device \
 		-device virtio-net-device,netdev=net0 \
-		-netdev user,id=net0,hostfwd=udp::6200-:2000 \
+		-netdev user,id=net0,hostfwd=udp::6200-:2000,hostfwd=tcp::6201-:80 \
 		-serial stdio
 
 run-inner: build
@@ -102,7 +102,7 @@ run-inner: build
 		-device virtio-keyboard-device  \
 		-device virtio-mouse-device \
 		-device virtio-net-device,netdev=net0 \
-		-netdev user,id=net0,hostfwd=udp::6200-:2000 \
+		-netdev user,id=net0,hostfwd=udp::6200-:2000,hostfwd=tcp::6201-:80 \
 		-serial stdio
 
 fdt:

os/src/drivers/bus/virtio.rs

@@ -1,6 +1,6 @@
 use crate::mm::{
-    frame_dealloc, kernel_token, FrameTracker, PageTable, PhysAddr, PhysPageNum,
+    frame_alloc_more, frame_dealloc, kernel_token, FrameTracker, PageTable, PhysAddr, PhysPageNum,
-    StepByOne, VirtAddr, frame_alloc_more,
+    StepByOne, VirtAddr,
 };
 use crate::sync::UPIntrFreeCell;
 use alloc::vec::Vec;
@@ -18,7 +18,9 @@ impl Hal for VirtioHal {
     fn dma_alloc(pages: usize) -> usize {
         let trakcers = frame_alloc_more(pages);
         let ppn_base = trakcers.as_ref().unwrap().last().unwrap().ppn;
-        QUEUE_FRAMES.exclusive_access().append(&mut trakcers.unwrap());
+        QUEUE_FRAMES
+            .exclusive_access()
+            .append(&mut trakcers.unwrap());
         let pa: PhysAddr = ppn_base.into();
         pa.0
     }

os/src/drivers/net/mod.rs

@@ -1,10 +1,10 @@
 use core::any::Any;
 
-use alloc::sync::Arc;
-use lazy_static::*;
-use virtio_drivers::{VirtIONet, VirtIOHeader};
 use crate::drivers::virtio::VirtioHal;
 use crate::sync::UPIntrFreeCell;
+use alloc::sync::Arc;
+use lazy_static::*;
+use virtio_drivers::{VirtIOHeader, VirtIONet};
 
 const VIRTIO8: usize = 0x10004000;
 
@@ -21,19 +21,24 @@ pub struct VirtIONetWrapper(UPIntrFreeCell<VirtIONet<'static, VirtioHal>>);
 
 impl NetDevice for VirtIONetWrapper {
     fn transmit(&self, data: &[u8]) {
-        self.0.exclusive_access().send(data).expect("can't send data")
+        self.0
+            .exclusive_access()
+            .send(data)
+            .expect("can't send data")
     }
 
     fn receive(&self, data: &mut [u8]) -> usize {
-        self.0.exclusive_access().recv(data).expect("can't receive data")
+        self.0
+            .exclusive_access()
+            .recv(data)
+            .expect("can't receive data")
     }
 }
 
 impl VirtIONetWrapper {
     pub fn new() -> Self {
         unsafe {
-            let virtio =
+            let virtio = VirtIONet::<VirtioHal>::new(&mut *(VIRTIO8 as *mut VirtIOHeader))
-                VirtIONet::<VirtioHal>::new(&mut *(VIRTIO8 as *mut VirtIOHeader))
                 .expect("can't create net device by virtio");
             VirtIONetWrapper(UPIntrFreeCell::new(virtio))
         }

os/src/main.rs

@@ -20,13 +20,13 @@ mod drivers;
 mod fs;
 mod lang_items;
 mod mm;
+mod net;
 mod sbi;
 mod sync;
 mod syscall;
 mod task;
 mod timer;
 mod trap;
-mod net;
 
 use crate::drivers::chardev::CharDevice;
 use crate::drivers::chardev::UART;

os/src/net/mod.rs

@@ -1,12 +1,20 @@
-pub mod udp;
 pub mod socket;
+pub mod tcp;
+pub mod udp;
+pub mod port_table;
 
 pub use lose_net_stack::IPv4;
 
-use alloc::{vec, sync::Arc};
+use alloc::{sync::Arc, vec};
-use lose_net_stack::{LoseStack, MacAddress, results::Packet};
+use lose_net_stack::{results::Packet, LoseStack, MacAddress, TcpFlags};
 
-use crate::{drivers::NET_DEVICE, sync::UPIntrFreeCell, net::socket::{get_socket, push_data}};
+use crate::{
+    drivers::NET_DEVICE,
+    net::socket::{get_socket, push_data},
+    sync::UPIntrFreeCell,
+};
+
+use self::{port_table::check_accept, socket::set_s_a_by_index};
 
 pub struct NetStack(UPIntrFreeCell<LoseStack>);
 
@@ -15,7 +23,7 @@ impl NetStack {
         unsafe {
             NetStack(UPIntrFreeCell::new(LoseStack::new(
                 IPv4::new(10, 0, 2, 15),
-                MacAddress::new([0x52, 0x54, 0x00, 0x12, 0x34, 0x56]) 
+                MacAddress::new([0x52, 0x54, 0x00, 0x12, 0x34, 0x56]),
             )))
         }
     }
@@ -25,13 +33,15 @@ lazy_static::lazy_static! {
     static ref LOSE_NET_STACK: Arc<NetStack> = Arc::new(NetStack::new());
 }
 
-
 pub fn net_interrupt_handler() {
     let mut recv_buf = vec![0u8; 1024];
 
     let len = NET_DEVICE.receive(&mut recv_buf);
 
-    let packet = LOSE_NET_STACK.0.exclusive_access().analysis(&recv_buf[..len]);
+    let packet = LOSE_NET_STACK
+        .0
+        .exclusive_access()
+        .analysis(&recv_buf[..len]);
 
     // println!("[kernel] receive a packet");
     // hexdump(&recv_buf[..len]);
@@ -39,10 +49,12 @@ pub fn net_interrupt_handler() {
     match packet {
         Packet::ARP(arp_packet) => {
             let lose_stack = LOSE_NET_STACK.0.exclusive_access();
-            let reply_packet = arp_packet.reply_packet(lose_stack.ip, lose_stack.mac).expect("can't build reply");
+            let reply_packet = arp_packet
+                .reply_packet(lose_stack.ip, lose_stack.mac)
+                .expect("can't build reply");
             let reply_data = reply_packet.build_data();
             NET_DEVICE.transmit(&reply_data)
-        },
+        }
 
         Packet::UDP(udp_packet) => {
             let target = udp_packet.source_ip;
@@ -53,6 +65,38 @@ pub fn net_interrupt_handler() {
                 push_data(socket_index, udp_packet.data.to_vec());
             }
         }
+
+        Packet::TCP(tcp_packet) => {
+            let target = tcp_packet.source_ip;
+            let lport = tcp_packet.dest_port;
+            let rport = tcp_packet.source_port;
+            let flags = tcp_packet.flags;
+
+            if flags.contains(TcpFlags::S) {
+                // if it has a port to accept, then response the request
+                if check_accept(lport, &tcp_packet).is_some() {
+                    let mut reply_packet = tcp_packet.ack();
+                    reply_packet.flags = TcpFlags::S | TcpFlags::A;
+                    NET_DEVICE.transmit(&reply_packet.build_data());
+                }
+                return;
+            } else if tcp_packet.flags.contains(TcpFlags::F) {
+                // tcp disconnected
+                let reply_packet = tcp_packet.ack();
+                NET_DEVICE.transmit(&reply_packet.build_data());
+
+                let mut end_packet = reply_packet.ack();
+                end_packet.flags |= TcpFlags::F;
+                NET_DEVICE.transmit(&end_packet.build_data());
+            } else if tcp_packet.flags.contains(TcpFlags::A) && tcp_packet.data_len == 0 {
+                return;
+            }
+
+            if let Some(socket_index) = get_socket(target, lport, rport) {
+                push_data(socket_index, tcp_packet.data.to_vec());
+                set_s_a_by_index(socket_index, tcp_packet.seq, tcp_packet.ack);
+            } 
+        }
         _ => {}
     }
 }

os/src/net/port_table.rs

@@ -0,0 +1,133 @@
+use alloc::{vec::Vec, sync::Arc};
+use lazy_static::lazy_static;
+use lose_net_stack::packets::tcp::TCPPacket;
+
+use crate::fs::File;
+use crate::sync::UPIntrFreeCell;
+use crate::task::TaskControlBlock;
+
+use super::tcp::TCP;
+
+pub struct Port {
+    pub port: u16,
+    pub receivable: bool,
+    pub schedule: Option<Arc<TaskControlBlock>>
+}
+
+lazy_static! {
+    static ref LISTEN_TABLE: UPIntrFreeCell<Vec<Option<Port>>> =
+        unsafe { UPIntrFreeCell::new(Vec::new()) };
+}
+
+pub fn listen(port: u16) -> Option<usize> {
+    let mut listen_table = LISTEN_TABLE.exclusive_access();
+    let mut index = usize::MAX;
+    for i in 0..listen_table.len() {
+        if listen_table[i].is_none() {
+            index = i;
+            break;
+        }
+    }
+
+    let listen_port = Port {
+        port,
+        receivable: false,
+        schedule: None
+    };
+
+    if index == usize::MAX {
+        listen_table.push(Some(listen_port));
+        Some(listen_table.len() - 1)
+    } else {
+        listen_table[index] = Some(listen_port);
+        Some(index)
+    }
+}
+
+// can accept request
+pub fn accept(listen_index: usize, task: Arc<TaskControlBlock>) {
+    let mut listen_table = LISTEN_TABLE.exclusive_access();
+    assert!(listen_index < listen_table.len());
+    let listen_port = listen_table[listen_index].as_mut();
+    assert!(listen_port.is_some());
+    let listen_port = listen_port.unwrap();
+    listen_port.receivable = true;
+    listen_port.schedule = Some(task);
+}
+
+pub fn port_acceptable(listen_index: usize) -> bool {
+    let mut listen_table = LISTEN_TABLE.exclusive_access();
+    assert!(listen_index < listen_table.len());
+
+    let listen_port = listen_table[listen_index].as_mut();
+    listen_port.map_or(false, |x| x.receivable)
+}
+
+// check whether it can accept request
+pub fn check_accept(port: u16, tcp_packet: &TCPPacket) -> Option<()> {
+    LISTEN_TABLE.exclusive_session(|listen_table| {
+        let mut listen_ports: Vec<&mut Option<Port>> = listen_table.iter_mut().filter(|x| match x {
+            Some(t) => t.port == port && t.receivable == true,
+            None => false,
+        }).collect();
+        if listen_ports.len() == 0 {
+            None
+        } else {
+            let listen_port = listen_ports[0].as_mut().unwrap();
+            let task = listen_port.schedule.clone().unwrap();
+            // wakeup_task(Arc::clone(&listen_port.schedule.clone().unwrap()));
+            listen_port.schedule = None;
+            listen_port.receivable = false;
+
+            accept_connection(port, tcp_packet, task);
+            Some(())
+        }
+    })
+}
+
+pub fn accept_connection(_port: u16, tcp_packet: &TCPPacket, task: Arc<TaskControlBlock>) {
+    let process = task.process.upgrade().unwrap();
+    let mut inner = process.inner_exclusive_access();
+    let fd = inner.alloc_fd();
+
+    let tcp_socket = TCP::new(tcp_packet.source_ip, tcp_packet.dest_port, tcp_packet.source_port, tcp_packet.seq, tcp_packet.ack);
+
+    inner.fd_table[fd] = Some(Arc::new(tcp_socket));
+
+    let cx = task.inner_exclusive_access().get_trap_cx();
+    cx.x[10] = fd;
+}
+
+// store in the fd_table, delete the listen table when close the application.
+pub struct PortFd(usize);
+
+impl PortFd {
+    pub fn new(port_index: usize) -> Self {
+        PortFd(port_index)
+    }
+}
+
+impl Drop for PortFd {
+    fn drop(&mut self) {
+        LISTEN_TABLE.exclusive_access()[self.0] = None
+    }
+}
+
+impl File for PortFd {
+    fn readable(&self) -> bool {
+        false
+    }
+
+    fn writable(&self) -> bool {
+        false
+    }
+
+    fn read(&self, _buf: crate::mm::UserBuffer) -> usize {
+        0
+    }
+
+    fn write(&self, _buf: crate::mm::UserBuffer) -> usize {
+        0
+    }
+}
+

os/src/net/socket.rs

@@ -5,19 +5,47 @@ use lose_net_stack::IPv4;
 
 use crate::sync::UPIntrFreeCell;
 
-
 // TODO: specify the protocol, TCP or UDP
 pub struct Socket {
     pub raddr: IPv4,                // remote address
     pub lport: u16,                 // local port
     pub rport: u16,                 // rempote port
-    pub buffers: VecDeque<Vec<u8>>  // datas
+    pub buffers: VecDeque<Vec<u8>>, // datas
+    pub seq: u32,
+    pub ack: u32
 }
 
 lazy_static! {
-    static ref SOCKET_TABLE:UPIntrFreeCell<Vec<Option<Socket>>> = unsafe {
+    static ref SOCKET_TABLE: UPIntrFreeCell<Vec<Option<Socket>>> =
-        UPIntrFreeCell::new(Vec::new())
+        unsafe { UPIntrFreeCell::new(Vec::new()) };
-    };
+}
+
+/// get the seq and ack by socket index
+pub fn get_s_a_by_index(index: usize) -> Option<(u32, u32)> {
+    let socket_table = SOCKET_TABLE.exclusive_access();
+
+    assert!(index < socket_table.len());
+
+    socket_table.get(index).map_or(None, |x| {
+        match x {
+            Some(x) => Some((x.seq, x.ack)),
+            None => None,
+        }
+    })
+}
+
+pub fn set_s_a_by_index(index: usize, seq: u32, ack: u32) {
+    let mut socket_table = SOCKET_TABLE.exclusive_access();
+
+    assert!(socket_table.len() > index);
+    assert!(socket_table[index].is_some());
+
+    let sock = socket_table[index]
+    .as_mut()
+    .unwrap();
+
+    sock.ack = ack;
+    sock.seq = seq;
 }
 
 pub fn get_socket(raddr: IPv4, lport: u16, rport: u16) -> Option<usize> {
@@ -30,7 +58,7 @@ pub fn get_socket(raddr: IPv4, lport: u16, rport: u16) -> Option<usize> {
 
         let sock = sock.as_ref().unwrap();
         if sock.raddr == raddr && sock.lport == lport && sock.rport == rport {
-            return Some(i)
+            return Some(i);
         }
     }
     None
@@ -54,7 +82,9 @@ pub fn add_socket(raddr: IPv4, lport: u16, rport: u16) -> Option<usize> {
         raddr,
         lport,
         rport,
-        buffers: VecDeque::new()
+        buffers: VecDeque::new(),
+        seq: 0,
+        ack: 0
     };
 
     if index == usize::MAX {
@@ -80,7 +110,11 @@ pub fn push_data(index: usize, data: Vec<u8>) {
     assert!(socket_table.len() > index);
     assert!(socket_table[index].is_some());
 
-    socket_table[index].as_mut().unwrap().buffers.push_back(data);
+    socket_table[index]
+        .as_mut()
+        .unwrap()
+        .buffers
+        .push_back(data);
 }
 
 pub fn pop_data(index: usize) -> Option<Vec<u8>> {

os/src/net/tcp.rs

@@ -0,0 +1,113 @@
+use alloc::vec;
+use lose_net_stack::MacAddress;
+use lose_net_stack::IPv4;
+use lose_net_stack::TcpFlags;
+use lose_net_stack::packets::tcp::TCPPacket;
+
+use crate::{drivers::NET_DEVICE, fs::File};
+
+use super::socket::get_s_a_by_index;
+use super::{
+    net_interrupt_handler,
+    socket::{add_socket, pop_data, remove_socket},
+    LOSE_NET_STACK,
+};
+
+// add tcp packet info to this structure
+pub struct TCP {
+    pub target: IPv4,
+    pub sport: u16,
+    pub dport: u16,
+    pub seq: u32,
+    pub ack: u32,
+    pub socket_index: usize,
+}
+
+impl TCP {
+    pub fn new(target: IPv4, sport: u16, dport: u16, seq: u32, ack: u32) -> Self {
+        let index = add_socket(target, sport, dport).expect("can't add socket");
+
+        Self {
+            target,
+            sport,
+            dport,
+            seq,
+            ack,
+            socket_index: index,
+        }
+    }
+}
+
+impl File for TCP {
+    fn readable(&self) -> bool {
+        true
+    }
+
+    fn writable(&self) -> bool {
+        true
+    }
+
+    fn read(&self, mut buf: crate::mm::UserBuffer) -> usize {
+        loop {
+            if let Some(data) = pop_data(self.socket_index) {
+                let data_len = data.len();
+                let mut left = 0;
+                for i in 0..buf.buffers.len() {
+                    let buffer_i_len = buf.buffers[i].len().min(data_len - left);
+
+                    buf.buffers[i][..buffer_i_len]
+                        .copy_from_slice(&data[left..(left + buffer_i_len)]);
+
+                    left += buffer_i_len;
+                    if left == data_len {
+                        break;
+                    }
+                }
+                return left;
+            } else {
+                net_interrupt_handler();
+            }
+        }
+    }
+
+    fn write(&self, buf: crate::mm::UserBuffer) -> usize {
+        let lose_net_stack = LOSE_NET_STACK.0.exclusive_access();
+
+        let mut data = vec![0u8; buf.len()];
+
+        let mut left = 0;
+        for i in 0..buf.buffers.len() {
+            data[left..(left + buf.buffers[i].len())].copy_from_slice(buf.buffers[i]);
+            left += buf.buffers[i].len();
+        }
+
+        let len = data.len();
+
+        // get sock and sequence
+        let (ack, seq) = get_s_a_by_index(self.socket_index).map_or((0, 0), |x| x);
+
+        let tcp_packet = TCPPacket {
+            source_ip: lose_net_stack.ip,
+            source_mac: lose_net_stack.mac,
+            source_port: self.sport,
+            dest_ip: self.target,
+            dest_mac: MacAddress::new([0xff, 0xff, 0xff, 0xff, 0xff, 0xff]),
+            dest_port: self.dport,
+            data_len: len,
+            seq,
+            ack,
+            flags: TcpFlags::A,
+            win: 65535,
+            urg: 0,
+            data: data.as_ref(),
+        };
+        NET_DEVICE.transmit(&tcp_packet.build_data());
+        len
+    }
+}
+
+impl Drop for TCP {
+    fn drop(&mut self) {
+        remove_socket(self.socket_index)
+    }
+}

os/src/net/udp.rs

@@ -1,18 +1,18 @@
-use alloc::vec;
-use lose_net_stack::MacAddress;
-use lose_net_stack::packets::udp::UDPPacket;
-use lose_net_stack::IPv4;
-use crate::fs::File;
 use super::net_interrupt_handler;
-use super::socket::{add_socket, remove_socket, pop_data};
+use super::socket::{add_socket, pop_data, remove_socket};
 use super::LOSE_NET_STACK;
 use super::NET_DEVICE;
+use crate::fs::File;
+use alloc::vec;
+use lose_net_stack::packets::udp::UDPPacket;
+use lose_net_stack::IPv4;
+use lose_net_stack::MacAddress;
 
 pub struct UDP {
     pub target: IPv4,
     pub sport: u16,
     pub dport: u16,
-    pub socket_index: usize
+    pub socket_index: usize,
 }
 
 impl UDP {
@@ -23,7 +23,7 @@ impl UDP {
             target,
             sport,
             dport,
-            socket_index: index
+            socket_index: index,
         }
     }
 }
@@ -45,7 +45,8 @@ impl File for UDP {
                 for i in 0..buf.buffers.len() {
                     let buffer_i_len = buf.buffers[i].len().min(data_len - left);
 
-                    buf.buffers[i][..buffer_i_len].copy_from_slice(&data[left..(left + buffer_i_len)]);
+                    buf.buffers[i][..buffer_i_len]
+                        .copy_from_slice(&data[left..(left + buffer_i_len)]);
 
                     left += buffer_i_len;
                     if left == data_len {
@@ -80,7 +81,7 @@ impl File for UDP {
             MacAddress::new([0xff, 0xff, 0xff, 0xff, 0xff, 0xff]),
             self.dport,
             len,
-            data.as_ref()
+            data.as_ref(),
         );
         NET_DEVICE.transmit(&udp_packet.build_data());
         len

os/src/syscall/mod.rs

@@ -1,5 +1,7 @@
 const SYSCALL_DUP: usize = 24;
 const SYSCALL_CONNECT: usize = 29;
+const SYSCALL_LISTEN: usize = 30;
+const SYSCALL_ACCEPT: usize = 31;
 const SYSCALL_OPEN: usize = 56;
 const SYSCALL_CLOSE: usize = 57;
 const SYSCALL_PIPE: usize = 59;
@@ -34,23 +36,25 @@ const SYSCALL_KEY_PRESSED: usize = 3001;
 mod fs;
 mod gui;
 mod input;
+mod net;
 mod process;
 mod sync;
 mod thread;
-mod net;
 
 use fs::*;
 use gui::*;
 use input::*;
+use net::*;
 use process::*;
 use sync::*;
 use thread::*;
-use net::*;
 
 pub fn syscall(syscall_id: usize, args: [usize; 3]) -> isize {
     match syscall_id {
         SYSCALL_DUP => sys_dup(args[0]),
         SYSCALL_CONNECT => sys_connect(args[0] as _, args[1] as _, args[2] as _),
+        SYSCALL_LISTEN => sys_listen(args[0] as _),
+        SYSCALL_ACCEPT => sys_accept(args[0] as _),
         SYSCALL_OPEN => sys_open(args[0] as *const u8, args[1] as u32),
         SYSCALL_CLOSE => sys_close(args[0]),
         SYSCALL_PIPE => sys_pipe(args[0] as *mut usize),

os/src/syscall/net.rs

@@ -1,7 +1,8 @@
-use alloc::sync::Arc;
+use crate::net::port_table::{listen, PortFd, accept, port_acceptable};
-use crate::net::IPv4;
 use crate::net::udp::UDP;
-use crate::task::current_process;
+use crate::net::{IPv4, net_interrupt_handler};
+use crate::task::{current_process, current_task, current_trap_cx};
+use alloc::sync::Arc;
 
 // just support udp
 pub fn sys_connect(raddr: u32, lport: u16, rport: u16) -> isize {
@@ -12,3 +13,41 @@ pub fn sys_connect(raddr: u32, lport: u16, rport: u16) -> isize {
     inner.fd_table[fd] = Some(Arc::new(udp_node));
     fd as isize
 }
+
+// listen a port
+pub fn sys_listen(port: u16) -> isize {
+    match listen(port) {
+        Some(port_index) => {
+            let process = current_process();
+            let mut inner = process.inner_exclusive_access();
+            let fd = inner.alloc_fd();
+            let port_fd = PortFd::new(port_index);
+            inner.fd_table[fd] = Some(Arc::new(port_fd));
+
+            // NOTICE: this return the port index, not the fd
+            port_index as isize
+        }
+        None => -1,
+    }
+}
+
+// accept a tcp connection
+pub fn sys_accept(port_index: usize) -> isize {
+    println!("accepting port {}", port_index);
+    
+    let task = current_task().unwrap();
+    accept(port_index, task);
+    // block_current_and_run_next();
+    
+    // NOTICE: There does not have interrupt handler, just call it munually.
+    loop {
+        net_interrupt_handler();
+
+        if !port_acceptable(port_index) {
+            break;
+        }
+    }
+
+    let cx = current_trap_cx();
+    cx.x[10] as isize
+}

user/src/bin/tcp_simplehttp.rs

@@ -0,0 +1,188 @@
+#![no_std]
+#![no_main]
+
+use alloc::string::{String, ToString};
+
+#[macro_use]
+extern crate user_lib;
+#[macro_use]
+extern crate alloc;
+
+// use http://localhost:6201/ to access the http server
+
+use user_lib::{read, write, listen, accept};
+
+// get url from the tcp request list.
+fn get_url_from_tcp_request(req: &[u8]) -> String {
+    let mut index = 0;
+    for i in 4..req.len() {
+        if req[i] == 0x20 {
+            index = i;
+            break;
+        }
+    }
+
+    String::from_utf8_lossy(&req[4..index]).to_string()
+}
+
+// just receive GET requests
+fn handle_tcp_client(client_fd: usize) -> bool {
+    // a buf to receive the data from the server
+    let mut buf = vec![0u8; 1024];
+
+    let len = read(client_fd as usize, &mut buf);
+
+    println!("receive {} bytes", len);
+    hexdump(&buf[..len as usize]);
+
+    // verify whether it is a valid HTTP request simply, [0x47,0x45,0x54, 0x20] is GET 
+    if len < 4 || buf[..4] != [0x47,0x45,0x54, 0x20] {
+        println!("it's not a valid http request");
+        return false;
+    }
+
+    let url = get_url_from_tcp_request(&buf);
+
+    if url == "/close" {
+        let content = r#"<!DOCTYPE html>
+        <html>
+        <head>
+        <title></title>
+        <meta charset="utf-8">
+        <meta name="viewport" content="width=device-width, initial-scale=1">
+        <link href="https://cdn.staticfile.org/twitter-bootstrap/5.1.1/css/bootstrap.min.css" rel="stylesheet">
+        <script src="https://cdn.staticfile.org/twitter-bootstrap/5.1.1/js/bootstrap.bundle.min.js"></script>
+        </head>
+        <body>
+        
+        <div class="container-fluid p-5 bg-danger text-white text-center">
+        <h1>server closed</h1>
+        </div>
+        </body>
+        </html>"#;
+        let response = format!("HTTP/1.1 200 OK\r\nContent-Type: text/html\r\nContent-Length: {}\r\nConnecion: Close\r\n\r\n{}", content.len(),content);
+        write(client_fd, response.as_bytes());
+        // terminate the connection immediately.
+        return true;
+    }
+
+    let content = r#"<!DOCTYPE html>
+        <html>
+        <head>
+        <title></title>
+        <meta charset="utf-8">
+        <meta name="viewport" content="width=device-width, initial-scale=1">
+        <link href="https://cdn.staticfile.org/twitter-bootstrap/5.1.1/css/bootstrap.min.css" rel="stylesheet">
+        <script src="https://cdn.staticfile.org/twitter-bootstrap/5.1.1/js/bootstrap.bundle.min.js"></script>
+        </head>
+        <body>
+        
+        <div class="container-fluid p-5 bg-primary text-white text-center">
+        <h1>rCore-tutorial-V3</h1>
+        <p>rCore-tutorial-V3 是一个 基于 RISC-V 架构的 类 Unix 内核.</p> 
+        </div>
+        
+        <div class="container mt-5">
+        <div class="row">
+            <div class="col-sm-4">
+            <h3>Rust</h3>
+            <p>Rust</p>
+            <p>Rust是一门系统编程语言，专注于安全，尤其是并发安全，支持函数式和命令式以及泛型等编程范式的多范式语言</p>
+            </div>
+            <div class="col-sm-4">
+            <h3>仓库地址</h3>        
+            <p>repo url</p>
+            <p>https://github.com/rcore-os/rCore-Tutorial-v3</p>
+            </div>
+            <div class="col-sm-4">
+            <h3>QQ 群号</h3>        
+            <p>Official QQ group number</p>
+            <p>735045051</p>
+            </div>
+        </div>
+        </div>
+        
+        <div class="container p-5 text-black text-center d-grid col-sm-4">
+        <p>点击下列按钮即可关闭服务器。</p>
+        <button type="button" class="btn btn-warning btn-block p-3" onclick="close_server()">关闭 server</button>
+        </div>
+        <script>
+        function close_server() {
+            location.href = "/close";
+        }
+        </script>
+        </body>
+        </html>"#;
+
+    let response = format!("HTTP/1.1 200 OK\r\nContent-Type: text/html\r\nContent-Length: {}\r\nConnecion: Close\r\n\r\n{}", content.len(),content);
+
+    // write a response
+    write(client_fd, response.as_bytes());
+
+    false
+}
+
+#[no_mangle]
+pub fn main() -> i32 {
+    println!("This is a very simple http server");
+
+    let tcp_fd = listen(80);
+
+    if tcp_fd < 0 {
+        println!("Failed to listen on port 80");
+        return -1;
+    }
+
+    loop {
+        let client = accept(tcp_fd as usize);
+        println!("client connected: {}", client);
+        
+        if client < 1 {
+            println!("Failed to accept a client on port 80");
+            return -1;
+        }
+    
+        if handle_tcp_client(client as usize) {
+            break;
+        }
+    }
+
+    println!("finish tcp test");
+
+    // String::from_utf8_lossy(&buf[..len as usize])
+
+    0
+}
+
+#[allow(unused)]
+pub fn hexdump(data: &[u8]) {
+    const PRELAND_WIDTH: usize = 70;
+    println!("{:-^1$}", " hexdump ", PRELAND_WIDTH);
+    for offset in (0..data.len()).step_by(16) {
+        for i in 0..16 {
+            if offset + i < data.len() {
+                print!("{:02x} ", data[offset + i]);
+            } else {
+                print!("{:02} ", "");
+            }
+        }
+
+        print!("{:>6}", ' ');
+
+        for i in 0..16 {
+            if offset + i < data.len() {
+                let c = data[offset + i];
+                if c >= 0x20 && c <= 0x7e {
+                    print!("{}", c as char);
+                } else {
+                    print!(".");
+                }
+            } else {
+                print!("{:02} ", "");
+            }
+        }
+
+        println!("");
+    }
+    println!("{:-^1$}", " hexdump end ", PRELAND_WIDTH);
+}

user/src/bin/udp.rs

@@ -8,7 +8,7 @@ extern crate user_lib;
 #[macro_use]
 extern crate alloc;
 
-use user_lib::{connect, write, read};
+use user_lib::{connect, read, write};
 
 #[no_mangle]
 pub fn main() -> i32 {

user/src/lib.rs

@@ -6,13 +6,13 @@
 
 #[macro_use]
 pub mod console;
-mod lang_items;
-mod syscall;
 mod file;
-mod task;
-mod sync;
 mod io;
+mod lang_items;
 mod net;
+mod sync;
+mod syscall;
+mod task;
 
 extern crate alloc;
 #[macro_use]
@@ -20,12 +20,12 @@ extern crate bitflags;
 
 use alloc::vec::Vec;
 use buddy_system_allocator::LockedHeap;
-use syscall::*;
 pub use file::*;
-pub use task::*;
-pub use sync::*;
 pub use io::*;
 pub use net::*;
+pub use sync::*;
+use syscall::*;
+pub use task::*;
 
 const USER_HEAP_SIZE: usize = 32768;
 

user/src/net.rs

@@ -3,3 +3,11 @@ use super::*;
 pub fn connect(ip: u32, sport: u16, dport: u16) -> isize {
     sys_connect(ip, sport, dport)
 }
+
+pub fn listen(sport: u16) -> isize {
+    sys_listen(sport)
+}
+
+pub fn accept(socket_fd: usize) -> isize {
+    sys_accept(socket_fd)
+}

user/src/syscall.rs

@@ -1,5 +1,7 @@
 const SYSCALL_DUP: usize = 24;
 const SYSCALL_CONNECT: usize = 29;
+const SYSCALL_LISTEN: usize = 30;
+const SYSCALL_ACCEPT: usize = 31;
 const SYSCALL_OPEN: usize = 56;
 const SYSCALL_CLOSE: usize = 57;
 const SYSCALL_PIPE: usize = 59;
@@ -50,7 +52,19 @@ pub fn sys_dup(fd: usize) -> isize {
 }
 
 pub fn sys_connect(dest: u32, sport: u16, dport: u16) -> isize {
-    syscall(SYSCALL_CONNECT, [dest as usize, sport as usize, dport as usize])
+    syscall(
+        SYSCALL_CONNECT,
+        [dest as usize, sport as usize, dport as usize],
+    )
+}
+
+// just listen for tcp connections now
+pub fn sys_listen(sport: u16) -> isize {
+    syscall(SYSCALL_LISTEN, [sport as usize, 0, 0])
+}
+
+pub fn sys_accept(socket_fd: usize) -> isize {
+    syscall(SYSCALL_ACCEPT, [socket_fd, 0, 0])
 }
 
 pub fn sys_open(path: &str, flags: u32) -> isize {
@@ -164,7 +178,6 @@ pub fn sys_condvar_wait(condvar_id: usize, mutex_id: usize) -> isize {
     syscall(SYSCALL_CONDVAR_WAIT, [condvar_id, mutex_id, 0])
 }
 
-
 pub fn sys_framebuffer() -> isize {
     syscall(SYSCALL_FRAMEBUFFER, [0, 0, 0])
 }