kernel/net: allocate socket rings from non-contiguous pages

tcp_input: on RST+ACK in SYN_SENT, unlock the socket mutex before
tcp_drop and leave through .drop_no_socket. tcp_drop frees the socket
and locks that mutex itself, so the network thread hung on it.

Assisted-by: Claude:claude-opus-5
Reviewed-on: #622
Reviewed-by: hidnplayr <hidnplayr@gmail.com>
Reviewed-by: Burer <burer@kolibrios.org>
Co-authored-by: Kiril Lipatov <lipatov.kiril@gmail.com>

drivers/ethernet/i8255x.asm

@@ -130,6 +130,8 @@ RU_STATUS_IDLE          = 0000b shl 2
 RU_STATUS_SUSPENDED     = 0001b shl 2
 RU_STATUS_NO_RESOURCES  = 0010b shl 2
 RU_STATUS_READY         = 0100b shl 2
+SCB_STATUS_CUS          = 11000000b     ; CU Status
+CU_STATUS_ACTIVE        = 10b shl 6
 SCB_STATUS_FCP          = 1 shl 8       ; Flow Control Pause
 SCB_STATUS_SWI          = 1 shl 10      ; Software Interrupt
 SCB_STATUS_MDI          = 1 shl 11      ; MDI read/write complete
@@ -183,6 +185,8 @@ struct  txfd
 
 ends
 
+TXFD_STATUS_C           = 1 shl 15
+
 TXFD_CMD_IA             = 1 shl 0
 TXFD_CMD_CFG            = 1 shl 1
 TXFD_CMD_TX             = 1 shl 2
@@ -628,6 +632,9 @@ reset:
         mov     ax, CU_START or INT_MASK
         out     dx, ax
         call    cmd_wait
+; cmd_wait only means the SCB accepted the command. The Configure below
+; reuses confcmd, so a slow chip would read it instead of our MAC.
+        call    confcmd_wait
 
 ;-------------
 ; Configure CU
@@ -652,6 +659,7 @@ reset:
         mov     ax, CU_START                            ; expect Interrupts from now on
         out     dx, ax
         call    cmd_wait
+        call    confcmd_wait
 
 ; Start media check timer
         mov     [ebx + device.state], ETH_LINK_DOWN
@@ -678,6 +686,11 @@ init_rx_ring:
 ;---------------------
 ; build rxfd structure
 
+        cmp     [ebx + device.rx_desc], 0       ; the RFD of an earlier reset
+        je      @f
+        invoke  NetFree, [ebx + device.rx_desc]
+        mov     [ebx + device.rx_desc], 0
+  @@:
         invoke  NetAlloc, 2000
         test    eax, eax
         jz      .out_of_mem
@@ -689,6 +702,7 @@ init_rx_ring:
         mov     [esi + sizeof.NET_BUFF + rxfd.command], RXFD_CMD_EL or RXFD_CMD_SUSPEND
         mov     [esi + sizeof.NET_BUFF + rxfd.link], eax
         mov     [esi + sizeof.NET_BUFF + rxfd.count], 0
+        mov     [esi + sizeof.NET_BUFF + rxfd.rx_buf_addr], 0xffffffff  ; simplified mode, no RBD
         mov     [esi + sizeof.NET_BUFF + rxfd.size], 1528
 
         ret
@@ -709,6 +723,15 @@ init_tx_ring:
         invoke  GetPhysAddr
         mov     ecx, TX_RING_SIZE
   .next_desc:
+; after a reset with frames still unreclaimed: free them, or transmit sees the
+; descriptor busy (virt_addr) and reports TX overrun forever
+        cmp     [esi + txfd.virt_addr], 0
+        je      @f
+        push    eax ecx
+        invoke  NetFree, [esi + txfd.virt_addr]
+        pop     ecx eax
+        mov     [esi + txfd.virt_addr], 0
+  @@:
         mov     [esi + txfd.status], 0
         mov     [esi + txfd.command], 0
         lea     edx, [eax + txfd.buf_addr]
@@ -763,7 +786,7 @@ proc transmit stdcall bufferptr
         lea     edi, [ebx + device.tx_ring + eax]
 
         ; Check if current descriptor is free or still in use
-        cmp     [edi + txfd.status], 0
+        cmp     [edi + txfd.virt_addr], 0               ; buffer not reclaimed yet
         jne     .overrun
 
         ; Fill in status and command values
@@ -786,6 +809,22 @@ proc transmit stdcall bufferptr
         mov     eax, edi
         invoke  GetPhysAddr
         set_io  [ebx + device.io_addr], 0
+
+        ; CU_START is only valid while the CU is idle or suspended:
+        ; wait for the previous frame to leave (1.2 ms at 10 Mbit)
+        push    eax ecx
+        set_io  [ebx + device.io_addr], REG_SCB_STATUS
+        mov     ecx, 100000
+  .cu_busy:
+        in      al, dx
+        and     al, SCB_STATUS_CUS
+        cmp     al, CU_STATUS_ACTIVE
+        jne     .cu_free
+        dec     ecx
+        jnz     .cu_busy
+        DEBUGF  2, "CU still active, starting anyway\n"
+  .cu_free:
+        pop     ecx eax
         set_io  [ebx + device.io_addr], REG_SCB_PTR
         out     dx, eax
 
@@ -854,7 +893,7 @@ int_handler:
 
         DEBUGF  1,"Status: %x\n", ax
 
-        test    ax, SCB_STATUS_FR               ; did we receive a frame?
+        test    ax, SCB_STATUS_FR or SCB_STATUS_RNR     ; frame received or receiver stopped?
         jz      .no_rx
 
         push    ax
@@ -901,6 +940,7 @@ int_handler:
         mov     [esi + sizeof.NET_BUFF + rxfd.command], RXFD_CMD_EL or RXFD_CMD_SUSPEND
         mov     [esi + sizeof.NET_BUFF + rxfd.link], eax
         mov     [esi + sizeof.NET_BUFF + rxfd.count], 0
+        mov     [esi + sizeof.NET_BUFF + rxfd.rx_buf_addr], 0xffffffff  ; simplified mode, no RBD
         mov     [esi + sizeof.NET_BUFF + rxfd.size], 1528
 
 ; restart RX
@@ -916,11 +956,22 @@ int_handler:
         mov     ax, RX_START
         out     dx, ax
         call    cmd_wait
-  .out_of_mem:
 
 ; Hand the frame over to the kernel
         jmp     [EthInput]
 
+  .out_of_mem:
+; The buffer is still our only RFD: drop the frame and reuse it
+        mov     esi, [esp]                      ; the buffer
+        mov     ecx, [esi + NET_BUFF.length]
+        dec     [ebx + device.packets_rx]       ; counted above, before the allocation
+        sub     dword [ebx + device.bytes_rx], ecx
+        sbb     dword [ebx + device.bytes_rx + 4], 0
+        inc     [ebx + device.packets_rx_drop]
+        add     esp, 12                         ; buffer, .rx_loop, ebx
+        mov     esi, [ebx + device.rx_desc]
+        jmp     .not_ok
+
   .not_ok:
 ; Reset the FD
         mov     [esi + sizeof.NET_BUFF + rxfd.status], 0
@@ -945,6 +996,27 @@ int_handler:
 
   .no_rx_:
         DEBUGF  1, "no more data\n"
+
+; With a single RFD the receiver sits in No Resources/Suspended whenever a
+; frame arrived before we re-armed it. Nothing restarts it but us.
+        set_io  [ebx + device.io_addr], 0
+        set_io  [ebx + device.io_addr], REG_SCB_STATUS
+        in      al, dx
+        and     al, SCB_STATUS_RUS
+        cmp     al, RU_STATUS_READY
+        je      .ru_ready
+        test    byte[esp], 1                    ; bit 0 of the saved status is reserved,
+        jnz     .ru_ready                       ; we mark it: one restart per IRQ
+        or      byte[esp], 1
+        movzx   eax, al
+        DEBUGF  1, "Restarting receiver, RU status %x\n", eax:2
+        mov     esi, [ebx + device.rx_desc]
+        push    ebx
+        test    [esi + sizeof.NET_BUFF + rxfd.status], RXFD_STATUS_C
+        jnz     .rx_loop                        ; a frame completed meanwhile
+        add     esp, 4
+        jmp     .not_ok                         ; re-arm the empty RFD
+  .ru_ready:
         pop     ax
 
   .no_rx:
@@ -955,13 +1027,13 @@ int_handler:
 
         push    eax
   .loop_tx:
-        mov     edi, [ebx + device.last_tx]
-        mov     eax, sizeof.txfd
-        mul     eax
+        mov     eax, [ebx + device.last_tx]
+        mov     edx, sizeof.txfd
+        mul     edx
         lea     edi, [ebx + device.tx_ring + eax]
 
-        cmp     [edi + txfd.status], 0
-        je      .tx_done
+        test    [edi + txfd.status], TXFD_STATUS_C      ; sent by the device?
+        jz      .tx_done
 
         cmp     [edi + txfd.virt_addr], 0
         je      .tx_done
@@ -970,6 +1042,7 @@ int_handler:
 
         push    [edi + txfd.virt_addr]
         mov     [edi + txfd.virt_addr], 0
+        mov     [edi + txfd.status], 0                  ; free for transmit again
         invoke  NetFree
 
         inc     [ebx + device.last_tx]
@@ -980,12 +1053,6 @@ int_handler:
         pop     eax
   .no_tx:
 
-        test    ax, RU_STATUS_NO_RESOURCES
-        jz      .not_out_of_resources
-
-        DEBUGF  2, "Out of resources!\n"
-
-  .not_out_of_resources:
         pop     edi esi ebx
         xor     eax, eax
         inc     eax
@@ -1079,6 +1146,25 @@ proc check_media_mii stdcall dev:dword
 endp
 
 
+; Wait (up to 1 s) until the device has executed the command in confcmd.
+align 4
+confcmd_wait:
+        mov     ecx, 1000                       ; udelay = Sleep(1), 1 ms
+  .loop:
+        test    [ebx + device.confcmd.status], TXFD_STATUS_C
+        jnz     .done
+        call    udelay
+        dec     ecx
+        jnz     .loop
+        movzx   eax, [ebx + device.confcmd.command]
+        DEBUGF  2, "Command 0x%x not completed\n", eax:4
+        ret
+  .done:
+        movzx   eax, [ebx + device.confcmd.command]
+        movzx   ecx, [ebx + device.confcmd.status]
+        DEBUGF  1, "Command 0x%x done, status 0x%x\n", eax:4, ecx:4
+        ret
+
 align 4
 cmd_wait:
 

kernel/trunk/core/heap.inc

@@ -463,7 +463,7 @@ proc kernel_alloc stdcall, size:dword
         and     eax, -PAGE_SIZE;
         mov     [size], eax
         and     eax, eax
-        jz      .err
+        jz      .err0
         mov     ebx, eax
         shr     ebx, 12
         mov     [pages_count], ebx
@@ -509,6 +509,13 @@ proc kernel_alloc stdcall, size:dword
         pop     ebx
         ret
 .err:
+        mov     eax, [lin_addr]
+        test    eax, eax
+        jz      .err0
+        mov     ecx, [pages_count]
+        call    release_pages
+        stdcall free_kernel_space, [lin_addr]
+.err0:
         xor     eax, eax
         pop     edi
         pop     ebx

kernel/trunk/core/memory.inc

@@ -1397,7 +1397,9 @@ proc create_ring_buffer stdcall, size:dword, flags:dword
         mov     [page_tabs + edi], eax
         mov     [page_tabs + edi + edx], eax
         invlpg  [ebx]
-        invlpg  [ebx+0x10000]
+        add     ebx, [size]
+        invlpg  [ebx]                   ; the mirror half
+        sub     ebx, [size]
         add     eax, 0x1000
         add     ebx, 0x1000
         add     edi, 4
@@ -1416,6 +1418,62 @@ proc create_ring_buffer stdcall, size:dword, flags:dword
         ret
 endp
 
+; Same as create_ring_buffer, but from non-contiguous pages.
+; Not for DMA. Free with kernel_free.
+align 4
+proc create_ring_buffer_sparse stdcall, size:dword, flags:dword
+           locals
+             buf_ptr  dd ?
+           endl
+
+        mov     eax, [size]
+        test    eax, eax
+        jz      .fail
+
+        add     eax, eax
+        stdcall alloc_kernel_space, eax
+        test    eax, eax
+        jz      .fail
+        mov     [buf_ptr], eax
+
+        push    ebx esi edi
+        mov     ebx, eax                ; page being mapped
+        mov     esi, [size]             ; distance to its mirror
+        mov     edi, esi
+        shr     edi, 12                 ; pages left
+  .page:
+        call    alloc_page
+        test    eax, eax
+        jz      .mm_fail
+        or      eax, [flags]
+        mov     edx, ebx
+        shr     edx, 12
+        mov     [page_tabs + edx*4], eax
+        invlpg  [ebx]
+        lea     edx, [ebx + esi]
+        shr     edx, 12
+        mov     [page_tabs + edx*4], eax
+        invlpg  [ebx + esi]
+        add     ebx, PAGE_SIZE
+        dec     edi
+        jnz     .page
+
+        mov     eax, [buf_ptr]
+        pop     edi esi ebx
+        ret
+
+  .mm_fail:
+        mov     eax, [buf_ptr]
+        mov     ecx, [size]
+        shr     ecx, 11                 ; both halves, in pages
+        call    release_pages
+        stdcall free_kernel_space, [buf_ptr]
+        pop     edi esi ebx
+        xor     eax, eax
+  .fail:
+        ret
+endp
+
 
 align 4
 proc print_mem

kernel/trunk/network/ARP.inc

@@ -83,6 +83,31 @@ macro arp_init {
 
 }
 
+;-----------------------------------------------------------------;
+;                                                                 ;
+; arp_clear_device: Empty the ARP table and counters of a removed ;
+;                   device.                                       ;
+;                                                                 ;
+;  IN:  edi = device number * 4                                   ;
+;                                                                 ;
+;-----------------------------------------------------------------;
+macro arp_clear_device {
+
+        xor     eax, eax
+        mov     [ARP_entries + edi], eax
+        mov     [ARP_packets_tx + edi], eax
+        mov     [ARP_packets_rx + edi], eax
+        mov     [ARP_conflicts + edi], eax
+
+        push    edi
+        imul    edi, (ARP_TABLE_SIZE * sizeof.ARP_entry)/4
+        add     edi, ARP_table
+        mov     ecx, (ARP_TABLE_SIZE * sizeof.ARP_entry)/2
+        rep stosw
+        pop     edi
+
+}
+
 ;-----------------------------------------------------------------;
 ;                                                                 ;
 ; arp_decrease_entry_ttls                                         ;
@@ -313,6 +338,9 @@ arp_output_request:
         DEBUGF  DEBUG_NETWORK_VERBOSE, "ARP_output_request: ip=%u.%u.%u.%u device=0x%x\n",\
         [esp]:1, [esp + 1]:1, [esp + 2]:1, [esp + 3]:1, ebx
 
+        test    ebx, ebx                        ; device is gone
+        jz      .exit
+
         mov     ax, ETHER_PROTO_ARP
         mov     ecx, sizeof.ARP_header
         mov     edx, ETH_BROADCAST              ; broadcast mac

kernel/trunk/network/IPv4.inc

@@ -105,6 +105,29 @@ macro   ipv4_init {
 }
 
 
+;-----------------------------------------------------------------;
+;                                                                 ;
+; ipv4_clear_device: Reset the IPv4 settings of a removed device, ;
+;                    so no route points to it anymore.            ;
+;                                                                 ;
+;  IN:  edi = device number * 4                                   ;
+;                                                                 ;
+;-----------------------------------------------------------------;
+macro   ipv4_clear_device {
+
+        xor     eax, eax
+        mov     [IPv4_address + edi], eax
+        mov     [IPv4_subnet + edi], eax
+        mov     [IPv4_nameserver + edi], eax
+        mov     [IPv4_gateway + edi], eax
+        mov     [IPv4_broadcast + edi], eax
+        mov     [IPv4_packets_tx + edi], eax
+        mov     [IPv4_packets_rx + edi], eax
+        mov     [IPv4_packets_dumped + edi], eax
+
+}
+
+
 ;-----------------------------------------------------------------;
 ;                                                                 ;
 ; Decrease TimeToLive of all fragment slots                       ;
@@ -757,6 +780,8 @@ ipv4_output_raw:
         push    esi eax
 
         call    ipv4_route
+        test    eax, eax
+        jz      .arp_error
         call    arp_ip_to_mac
 
         test    eax, 0xffff0000         ; error bits
@@ -967,6 +992,8 @@ ipv4_route:
 ; Check for on-link
         xor     edi, edi
   .loop:
+        cmp     [net_device_list + edi], 0      ; skip slots without a device
+        je      .next
         mov     ebx, [IPv4_address + edi]
         and     ebx, [IPv4_subnet + edi]
         jz      .next
@@ -983,7 +1010,10 @@ ipv4_route:
         mov     edi, 4                  ; skip loopback device
   .loop_gw:
         cmp     [IPv4_gateway + edi], 0
+        je      .next_gw
+        cmp     [net_device_list + edi], 0
         jne     .found_gw
+  .next_gw:
         add     edi, 4
         cmp     edi, 4*NET_DEVICES_MAX
         jb      .loop_gw
@@ -1049,14 +1079,23 @@ ipv4_route:
         cmp     eax, 0xffffffff
         je      @f
 
+; An interface without an address (DHCP not done yet, or the lease
+; dropped when the link went down) can send nothing but broadcasts: with
+; address and mask both zero every destination compared as on-link, and
+; the stack went asking ARP for internet addresses on behalf of 0.0.0.0.
+        test    edx, edx
+        jz      .fail
+
 ; Check if we should route to gateway or not
-        mov     ebx, [IPv4_address + edi]
+        mov     ebx, edx
         and     ebx, [IPv4_subnet + edi]
         mov     ecx, eax
         and     ecx, [IPv4_subnet + edi]
         cmp     ecx, ebx
         je      @f
         mov     eax, [IPv4_gateway + edi]
+        test    eax, eax
+        jz      .fail                                ; off-link and no gateway
   @@:
         DEBUGF  DEBUG_NETWORK_VERBOSE, "IPv4_route: %u\n", edi
         ret

kernel/trunk/network/ethernet.inc

@@ -61,6 +61,41 @@ macro   eth_init {
 
 }
 
+;-----------------------------------------------------------------;
+;                                                                 ;
+; eth_clear_device: Drop the frames of a removed device that are  ;
+;                   still waiting in the input queue, their       ;
+;                   NET_BUFF.device will not be valid anymore.    ;
+;                                                                 ;
+;  IN:  ebx = device ptr                                          ;
+;                                                                 ;
+;-----------------------------------------------------------------;
+macro   eth_clear_device {
+
+local   .loop, .done
+
+        spin_lock_irqsave
+        mov     esi, [ETH_frame_head]
+  .loop:
+        cmp     esi, ETH_frame_head
+        je      .done
+        mov     eax, esi
+        mov     esi, [esi + NET_BUFF.NextPtr]
+        cmp     [eax + NET_BUFF.device], ebx
+        jne     .loop
+
+; unlink it, ETH_frame_head/tail double as the NextPtr/PrevPtr of the list head
+        mov     ecx, [eax + NET_BUFF.PrevPtr]
+        mov     [ecx + NET_BUFF.NextPtr], esi
+        mov     [esi + NET_BUFF.PrevPtr], ecx
+        dec     [ETH_frame_queued]
+        stdcall net_buff_free, eax
+        jmp     .loop
+  .done:
+        spin_unlock_irqrestore
+
+}
+
 align 4
 ; This function is called by ethernet drivers.
 ; Push the received ethernet packet onto the ethernet input queue.
@@ -245,6 +280,9 @@ eth_output:
 
         DEBUGF  DEBUG_NETWORK_VERBOSE, "ETH_output: size=%u device=%x\n", ecx, ebx
 
+        test    ebx, ebx
+        jz      .no_device
+
         cmp     ecx, [ebx + ETH_DEVICE.mtu]
         ja      .too_large
 
@@ -295,11 +333,16 @@ eth_output:
         ret
 
   .too_large:
-        inc     [eax + NET_DEVICE.packets_tx_err]
+        inc     [ebx + NET_DEVICE.packets_tx_err]
         DEBUGF  DEBUG_NETWORK_VERBOSE, "ETH_output: Packet too large!\n"
         xor     eax, eax
         ret
 
+  .no_device:
+        DEBUGF  DEBUG_NETWORK_ERROR, "ETH_output: no device!\n"
+        xor     eax, eax
+        ret
+
 
 
 ;-----------------------------------------------------------------;

kernel/trunk/network/socket.inc

@@ -198,6 +198,10 @@ ends
 
 SOCKET_STRUCT_SIZE      = 4096          ; in bytes
 
+if sizeof.STREAM_SOCKET > SOCKET_STRUCT_SIZE
+  err "STREAM_SOCKET does not fit in SOCKET_STRUCT_SIZE"
+end if
+
 SOCKET_QUEUE_SIZE       = 10            ; maximum number of incoming packets queued for 1 socket
 ; the incoming packet queue for sockets is placed in the socket struct itself, at this location from start
 SOCKET_QUEUE_LOCATION   = (SOCKET_STRUCT_SIZE - SOCKET_QUEUE_SIZE*sizeof.socket_queue_entry - sizeof.queue)
@@ -1647,7 +1651,7 @@ socket_ring_create:
         mov     esi, eax
 
         push    edx
-        stdcall create_ring_buffer, SOCKET_BUFFER_SIZE, PG_SWR
+        stdcall create_ring_buffer_sparse, SOCKET_BUFFER_SIZE, PG_SWR
         pop     edx
         test    eax, eax
         jz      .fail

kernel/trunk/network/stack.inc

@@ -597,6 +597,16 @@ net_remove_device:
         mov     dword [edi-4], eax
         dec     [net_device_count]
 
+;-----------------------------------------------------------------
+; Forget everything the protocols still know about this interface.
+; Otherwise its IP address keeps matching in ipv4_route, and output
+; ends up calling through the now empty net_device_list slot.
+
+        sub     edi, net_device_list + 4        ; device number * 4
+        ipv4_clear_device
+        arp_clear_device
+        eth_clear_device
+
         call    net_send_event
 
         xor     eax, eax

kernel/trunk/network/tcp_input.inc

@@ -1422,10 +1422,14 @@ endl
         test    [edx + TCP_header.Flags], TH_ACK
         jz      .drop
 
-        mov     eax, ebx
+        push    ebx
+        lea     ecx, [ebx + SOCKET.mutex]
+        call    mutex_unlock
+        pop     eax
+
         mov     ebx, ECONNREFUSED
         call    tcp_drop
-        jmp     .drop
+        jmp     .drop_no_socket
        @@:
 
 ;-----------------------------------------------------------------------------------

kernel/trunk/network/tcp_output.inc

@@ -234,23 +234,25 @@ endl
         mov     ebx, TCP_max_win
         shl     ebx, cl
         pop     ecx
-        sub     ebx, [eax + TCP_SOCKET.RCV_ADV]
-        add     ebx, [eax + TCP_SOCKET.RCV_NXT]
+
+; Clamp to available window first, then subtract what the peer already knows (as in BSD)
 
         cmp     ebx, ecx
-        jl      @f
+        jbe     @f
         mov     ebx, ecx
        @@:
+        sub     ebx, [eax + TCP_SOCKET.RCV_ADV]
+        add     ebx, [eax + TCP_SOCKET.RCV_NXT]
 
         DEBUGF  DEBUG_NETWORK_VERBOSE, "TCP_output: we can increase window by %d bytes\n", ebx
 
         mov     edi, [eax + TCP_SOCKET.t_maxseg]
         shl     edi, 1
-        cmp     ebx, edi
-        jae     .send
+        cmp     ebx, edi                                ; signed: may be negative if window shrank
+        jge     .send
 
         cmp     ebx, SOCKET_BUFFER_SIZE/2
-        jae     .send
+        jge     .send
 
   .no_window:
 

kernel/trunk/network/tcp_usreq.inc

@@ -180,6 +180,8 @@ tcp_connect:
 
   .nomem:
         pop     edx eax
+        lea     ecx, [eax + SOCKET.mutex]
+        call    mutex_unlock
         xor     eax, eax
         dec     eax
         mov     ebx, ENOMEM
@@ -194,6 +196,8 @@ tcp_connect:
   .enoroute:
         pop     eax
         popa
+        lea     ecx, [eax + SOCKET.mutex]
+        call    mutex_unlock
         xor     eax, eax
         dec     eax
         mov     ebx, EADDRNOTAVAIL

programs/develop/libraries/http/http.asm

@@ -1618,21 +1618,23 @@ endl
 
 ; Open a new TCP socket
         mcall   socket, AF_INET4, SOCK_STREAM, 0
-        test    eax, eax
-        jz      .error3
+        cmp     eax, -1
+        je      .error3
         mov     [socketnum], eax
         DEBUGF  1, "Socket: 0x%x\n", eax
 
 ; Connect to the server
         mcall   connect, [socketnum], [sockaddr], 18
         test    eax, eax
-        jnz     .error3
+        jnz     .error4
         DEBUGF  1, "Socket is now connected.\n"
 
         invoke  freeaddrinfo            ; Free allocated memory
         mov     eax, [socketnum]
         ret
 
+  .error4:
+        mcall   close, [socketnum]
   .error3:
         DEBUGF  2, "Could not connect to the remote server\n"
         invoke  freeaddrinfo            ; Free allocated memory