net: close oldest sock if available socks run out

- By default, smoltcp by default reset any new connections
    if there is no available socket

src/main.rs

@@ -1,7 +1,7 @@
 #![cfg_attr(not(test), no_main)]
 #![cfg_attr(not(test), no_std)]
 
-use core::marker::PhantomData;
+use core::{marker::PhantomData, u32};
 
 use cortex_m_rt::entry;
 use log::{debug, info};
@@ -82,6 +82,8 @@ fn main() -> ! {
 
     let eth_data_buffer = unsafe { addr_of_mut!(ETH_DATA_BUFFER).as_mut().unwrap() };
 
+    let mut sock_ts: [u32; net::net::NUM_OF_SOCKETS] = [0; net::net::NUM_OF_SOCKETS];
+
     loop {
         wd.feed();
 
@@ -183,6 +185,10 @@ fn main() -> ! {
                     thermostat.start_tec_readings_conversion();
                 }
 
+                let mut num_of_connected_sock: u8 = 0;
+                let mut oldest_connected_sock_ts: u32 = u32::MAX;
+                let mut oldest_connected_sock_id: usize = 0;
+
                 net::net::for_each(|mut socket, id| {
                     if net::net::eth_is_socket_active(socket) && net::net::eth_is_socket_connected(socket) {
                         if net::net::eth_can_sock_recv(socket) && net::net::eth_can_sock_send(socket) {
@@ -204,8 +210,35 @@ fn main() -> ! {
                                 );
                             }
                         }
+
+                        num_of_connected_sock += 1;
+
+                        if sock_ts[id] == 0 {
+                            sock_ts[id] = sys_timer::now();
+                        }
+                        if oldest_connected_sock_ts > sock_ts[id] {
+                            oldest_connected_sock_ts = sock_ts[id];
+                            oldest_connected_sock_id = id;
+                        }
+                    } else {
+                        sock_ts[id] = 0;
+                    }
+                });
+
+                if num_of_connected_sock == net::net::NUM_OF_SOCKETS as u8 {
+                    let mut sock_handle = net::net::eth_get_sock_handle(oldest_connected_sock_id);
+                    net::cmd_handler::send_response(
+                        eth_data_buffer,
+                        net::cmd_handler::ResponseEnum::ConnectionClose,
+                        None,
+                        &mut sock_handle,
+                    );
+                    net::net::eth_poll_iface();
+                    debug!("Waiting for ConnectionClose msg to be sent");
+                    while !net::net::eth_is_data_sent() { }
+                    net::net::eth_close_socket_by_id(oldest_connected_sock_id);
+                    debug!("Closing socket id: {:?}", oldest_connected_sock_id);
                 }
-                })
             }
             State::SaveLdThermostatSettings => {
                 // State Transition

src/net/cmd_handler.rs

@@ -31,6 +31,7 @@ pub enum ResponseEnum {
     InvalidDatatype,
     InvalidCmd,
     HardReset,
+    ConnectionClose,
 }
 
 pub type MsgType = Option<&'static str>;

src/net/net.rs

@@ -47,6 +47,7 @@ pub struct ServerHandle {
     dma: EthernetDMA<'static, 'static>,
     phy: EthernetPhy<EthernetMACWithMii<Pin<'A', 2, Alternate<11>>, Pin<'C', 1, Alternate<11>>>>,
     link_was_up: bool,
+    data_sent: bool,
 }
 pub type EthernetPins = EthPins<PA1<Input>, PA7<Input>, PB11<Input>, PB12<Input>, PB13<Input>, PC4<Input>, PC5<Input>>;
 pub struct EthernetMgmtPins {
@@ -55,7 +56,7 @@ pub struct EthernetMgmtPins {
 }
 pub type EthInterface = Interface;
 
-pub const NUM_OF_SOCKETS: usize = 4;
+pub const NUM_OF_SOCKETS: usize = 4 + 1;
 const TCP_BUFFER_SIZE: usize = 4096;
 static mut RX_RING: Option<[RxRingEntry; 8]> = None;
 static mut TX_RING: Option<[TxRingEntry; 8]> = None;
@@ -138,7 +139,7 @@ impl ServerHandle {
         let tcp_handles = {
             // Do not use NUM_OF_SOCKETS to define array size to
             //  remind developers to create/remove tcp_handles accordingly after changing NUM_OF_SOCKETS
-            let mut tcp_handles: [MaybeUninit<SocketHandle>; 4] = unsafe { MaybeUninit::uninit().assume_init() };
+            let mut tcp_handles: [MaybeUninit<SocketHandle>; 5] = unsafe { MaybeUninit::uninit().assume_init() };
 
             macro_rules! create_tcp_handle {
                 ($rx_storage:ident, $tx_storage:ident, $handle:expr) => {
@@ -155,8 +156,9 @@ impl ServerHandle {
             create_tcp_handle!(RX_STORAGE1, TX_STORAGE1, tcp_handles[1]);
             create_tcp_handle!(RX_STORAGE2, TX_STORAGE2, tcp_handles[2]);
             create_tcp_handle!(RX_STORAGE3, TX_STORAGE3, tcp_handles[3]);
+            create_tcp_handle!(RX_STORAGE4, TX_STORAGE4, tcp_handles[4]);
 
-            unsafe { mem::transmute::<_, [SocketHandle; 4]>(tcp_handles) }
+            unsafe { mem::transmute::<_, [SocketHandle; 5]>(tcp_handles) }
         };
 
         for i in 0..NUM_OF_SOCKETS {
@@ -189,6 +191,7 @@ impl ServerHandle {
                 dma: dma,
                 phy: phy,
                 link_was_up: false,
+                data_sent: true,
             };
 
             unsafe {
@@ -249,6 +252,7 @@ impl ServerHandle {
             cortex_m::interrupt::free(|_| {
                 match socket.send_slice(&buffer[..num_bytes]) {
                     Ok(_) => {
+                        self.data_sent = false;
                         info!("Enqueued {} bytes.", num_bytes);
                     }
                     Err(err) => {
@@ -501,6 +505,46 @@ pub fn eth_close_socket(socket_handles: SocketHandle) {
     }
 }
 
+pub fn eth_get_sock_handle(id: usize) -> SocketHandle {
+    unsafe {
+        if let Some(ref mut server_handle) = SERVER_HANDLE {
+            server_handle.socket_handles[id]
+        } else {
+            panic!("eth_get_sock_handle is called before init");
+        }
+    }
+}
+
+pub fn eth_close_socket_by_id(id: usize) {
+    unsafe {
+        if let Some(ref mut server_handle) = SERVER_HANDLE {
+            server_handle.close_socket(server_handle.socket_handles[id])
+        } else {
+            panic!("eth_close_socket_by_id is called before init");
+        }
+    }
+}
+
+pub fn eth_is_data_sent() -> bool {
+    unsafe {
+        if let Some(ref mut server_handle) = SERVER_HANDLE {
+            server_handle.data_sent
+        } else {
+            panic!("eth_is_data_sent is called before init");
+        }
+    }
+}
+
+fn eth_set_data_sent(val: bool) {
+    unsafe {
+        if let Some(ref mut server_handle) = SERVER_HANDLE {
+            server_handle.data_sent = val;
+        } else {
+            panic!("eth_is_data_sent is called before init");
+        }
+    }
+}
+
 pub fn for_each<F: FnMut(SocketHandle, usize)>(mut callback: F) {
     unsafe {
         if let Some(ref mut server_handle) = SERVER_HANDLE {
@@ -521,6 +565,9 @@ fn ETH() {
     if interrupt_reason.rx {
         eth_poll_iface();
     }
+    if interrupt_reason.tx {
+        eth_set_data_sent(true);
+    }
     debug!("Ethernet Interrupt{:?}", interrupt_reason);
 }