Mbed OS Reference | LWIPStack.h Source File

 /* mbed Microcontroller Library
  * Copyright (c) 2017 ARM Limited
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  *     http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
 
 #ifndef LWIPSTACK_H_
 #define LWIPSTACK_H_
 
 #include "lwip/tcpip.h"
 #include "lwip/tcp.h"
 #include "lwip/ip.h"
 #include "lwip/api.h"
 #include "netif/etharp.h"
 #include "lwip/ethip6.h"
 #include "netsocket/nsapi_types.h"
 #include "netsocket/EMAC.h"
 #include "netsocket/L3IP.h"
 #include "netsocket/PPP.h"
 #include "netsocket/OnboardNetworkStack.h"
 #include "LWIPMemoryManager.h"
 
 #if LWIP_IPV6
 #include "lwip/ip6_addr.h"
 #define IP_ADDR_VALID IP6_ADDR_VALID
 #else
 #define IP_ADDR_VALID 0
 #endif
 
 class LWIP : public OnboardNetworkStack, private mbed::NonCopyable<LWIP> {
 public:
     using NetworkStack::get_ip_address;
     static LWIP &get_instance();
 
     class Interface final : public OnboardNetworkStack::Interface {
     public:
         /** Set IP address to LWIP stack
          *
          * This function can set both IPv4 or IPv6 address to LWIP stack.
          *
          * bringup() can only take one IP address and in dual stack case
          * another IP address can be set using this function.
          *
          * IPv4 or IPv6 address should be in format of https://tools.ietf.org/html/draft-main-ipaddr-text-rep-00.
          *
          * @param    ip         IP address to be used for the interface as IPv4 or IPv6 address string.
          *                      This parameter should not be NULL.
          * @param    netmask    Net mask to be used for the interface as IPv4 address string or NULL.
          *                      NULL value will set this value to 255.255.255.255.
          *                      This parameter will be ignored for IPv6 ip argument.
          * @param    gw         Gateway address to be used for the interface as IPv4 address string or NULL
          *                      NULL value will set this value to 0.0.0.0
          *                      This parameter will be ignored for IPv6 ip argument.
          * @param    ipv6_flag  Provide this flag for IPv6 state flag override. For example, you can set IP6_ADDR_PREFERRED.
          *                      Default value is IP6_ADDR_VALID. For IPv4, this value will be ignored.
          * @return              NSAPI_ERROR_OK on success, or error code
          */
         nsapi_error_t set_ip_address(const char *ip,
                                      const char *netmask,
                                      const char *gw,
                                      uint8_t ipv6_flag = IP_ADDR_VALID
                                     ) override;
 
         /** Connect the interface to the network
          *
          * Sets up a connection on specified network interface, using DHCP or provided network details. If the @a dhcp is set to
          * true all the remaining parameters are ignored.
          *
          * @param    dhcp       true if the network details should be acquired using DHCP
          * @param    ip         IP address to be used for the interface as "W:X:Y:Z" or NULL
          * @param    netmask    Net mask to be used for the interface as "W:X:Y:Z" or NULL
          * @param    gw         Gateway address to be used for the interface as "W:X:Y:Z" or NULL
          * @param    stack      Allow manual selection of IPv4 and/or IPv6.
          * @param    blocking   Specify whether bringup blocks for connection completion.
          * @return              NSAPI_ERROR_OK on success, or error code
          */
         nsapi_error_t bringup(bool dhcp, const char *ip,
                               const char *netmask, const char *gw,
                               nsapi_ip_stack_t stack = DEFAULT_STACK,
                               bool blocking = true
                              ) override;
 
         /** Disconnect interface from the network
          *
          * After this call the network interface is inactive, to use it again user needs to call @a mbed_ipstack_bringup again.
          *
          * @return    NSAPI_ERROR_OK on success, or error code
          */
         nsapi_error_t bringdown() override;
 
         /** Register callback for status reporting
          *
          *  The specified status callback function will be called on status changes
          *  on the network. The parameters on the callback are the event type and
          *  event-type dependent reason parameter.
          *
          *  @param status_cb The callback for status changes
          */
         void attach(mbed::Callback<void(nsapi_event_t, intptr_t)> status_cb) override;
 
         /** Get the connection status
          *
          *  @return         The connection status according to ConnectionStatusType
          */
         nsapi_connection_status_t get_connection_status() const override;
 
         /** Return netif interface name
          *
          * @return       netif name  eg "en0"
         */
         char *get_interface_name(char *buf) override;
 
         /** Return MAC address of the network interface
          *
          * @return              MAC address as "V:W:X:Y:Z"
          */
         char *get_mac_address(char *buf, nsapi_size_t buflen) override;
 
         /** @copydoc OnboardNetworkStack::Interface::get_ip_address */
         nsapi_error_t get_ip_address(SocketAddress *address) override;
 
         /** Get the IPv6 link local address in SocketAddress representation
          *
          *  @address        SocketAddress representation of the link local IPv6 address
          *  @return         NSAPI_ERROR_OK on success, or error code
          */
         nsapi_error_t get_ipv6_link_local_address(SocketAddress *address) override;
 
         /** Copies netmask of the network interface to user supplied buffer
          *
          * @param    buf        buffer to which netmask will be copied as "W:X:Y:Z"
          * @param    buflen     size of supplied buffer
          * @return              Pointer to a buffer, or NULL if the buffer is too small
          */
         nsapi_error_t get_netmask(SocketAddress *address) override;
 
         /** Copies gateway address of the network interface to user supplied buffer
          *
          * @param    buf        buffer to which gateway address will be copied as "W:X:Y:Z"
          * @param    buflen     size of supplied buffer
          * @return              Pointer to a buffer, or NULL if the buffer is too small
          */
         nsapi_error_t get_gateway(SocketAddress *address) override;
 
     private:
         friend class LWIP;
 
         Interface();
 
         nsapi_error_t set_dhcp();
         static void netif_link_irq(struct netif *netif);
         static void netif_status_irq(struct netif *netif);
         static Interface *our_if_from_netif(struct netif *netif);
         static void delete_interface(OnboardNetworkStack::Interface **interface_out);
 
 #if LWIP_ETHERNET
         static err_t emac_low_level_output(struct netif *netif, struct pbuf *p);
         void emac_input(net_stack_mem_buf_t *buf);
         void emac_state_change(bool up);
 #if LWIP_IGMP
         static err_t emac_igmp_mac_filter(struct netif *netif, const ip4_addr_t *group, enum netif_mac_filter_action action);
 #endif
 #if LWIP_IPV6_MLD
         static err_t emac_mld_mac_filter(struct netif *netif, const ip6_addr_t *group, enum netif_mac_filter_action action);
 #endif
 
         static err_t emac_if_init(struct netif *netif);
 #endif
 
 #if LWIP_L3IP
 #if LWIP_IPV4
         static err_t l3ip4_output(struct netif *netif, struct pbuf *p, const ip4_addr_t *ipaddr);
 #endif
 #if LWIP_IPV6
         static err_t l3ip6_output(struct netif *netif, struct pbuf *p, const ip6_addr_t *ipaddr);
 #endif
         void l3ip_input(net_stack_mem_buf_t *buf);
         void l3ip_state_change(bool up);
 #if LWIP_IGMP
         static err_t l3ip_multicast_ipv4_filter(struct netif *netif, const ip4_addr_t *group, enum netif_mac_filter_action action);
 #endif
 #if LWIP_IPV6_MLD
         static err_t l3ip_multicast_ipv6_filter(struct netif *netif, const ip6_addr_t *group, enum netif_mac_filter_action action);
 #endif
 
         static err_t l3ip_if_init(struct netif *netif);
 #endif
 
 #if PPP_SUPPORT
 #if PPP_IPV4_SUPPORT && LWIP_IPV4
         static err_t ppp4_output(struct netif *netif, struct pbuf *p, const ip4_addr_t *ipaddr);
 #endif
 #if PPP_IPV6_SUPPORT && LWIP_IPV6
         static err_t ppp6_output(struct netif *netif, struct pbuf *p, const ip6_addr_t *ipaddr);
 #endif
         void ppp_input(net_stack_mem_buf_t *buf);
         void ppp_state_change(bool up);
         static err_t ppp_if_init(struct netif *netif);
 #endif
 
         union {
 #if LWIP_ETHERNET
             EMAC *emac; /**< HW specific emac implementation */
 #endif
 #if LWIP_L3IP
             L3IP *l3ip; /**<  L3IP implementation */
 #endif
 #if PPP_SUPPORT
             PPP *ppp; /**< PPP implementation */
 #endif
             void *hw; /**< alternative implementation pointer - used for PPP */
         };
 
         mbed_rtos_storage_semaphore_t remove_interface_sem;
         osSemaphoreId_t remove_interface;
         mbed_rtos_storage_semaphore_t linked_sem;
         osSemaphoreId_t linked;
         mbed_rtos_storage_semaphore_t unlinked_sem;
         osSemaphoreId_t unlinked;
         mbed_rtos_storage_semaphore_t has_any_addr_sem;
         osSemaphoreId_t has_any_addr;
 #define HAS_ANY_ADDR 1
 #if PREF_ADDR_TIMEOUT
         mbed_rtos_storage_semaphore_t has_pref_addr_sem;
         osSemaphoreId_t has_pref_addr;
 #define HAS_PREF_ADDR 2
 #endif
 #if BOTH_ADDR_TIMEOUT
         mbed_rtos_storage_semaphore_t has_both_addr_sem;
         osSemaphoreId_t has_both_addr;
 #define HAS_BOTH_ADDR 4
 #endif
         char _interface_name[NSAPI_INTERFACE_NAME_MAX_SIZE];
         char has_addr_state;
         nsapi_connection_status_t connected;
         bool dhcp_started;
         bool dhcp_has_to_be_set;
         bool blocking;
         bool ppp_enabled;
         mbed::Callback<void(nsapi_event_t, intptr_t)> client_callback;
         struct netif netif;
         static Interface *list;
         Interface *next;
         LWIPMemoryManager *memory_manager;
     };
 
     /** Register a network interface with the IP stack
      *
      * Connects EMAC layer with the IP stack and initializes all the required infrastructure.
      * This function should be called only once for each available interface.
      *
      * @param      emac             EMAC HAL implementation for this network interface
      * @param      default_if       true if the interface should be treated as the default one
      * @param[out] interface_out    pointer to stack interface object controlling the EMAC
      * @return                      NSAPI_ERROR_OK on success, or error code
      */
     nsapi_error_t add_ethernet_interface(EMAC &emac, bool default_if, OnboardNetworkStack::Interface **interface_out) override;
 
     /** Register a network interface with the IP stack
      *
      * Connects L3IP layer with the IP stack and initializes all the required infrastructure.
      * This function should be called only once for each available interface.
      *
      * @param      l3ip             L3IP HAL implementation for this network interface
      * @param      default_if       true if the interface should be treated as the default one
      * @param[out] interface_out    pointer to stack interface object controlling the L3IP
      * @return                      NSAPI_ERROR_OK on success, or error code
      */
     nsapi_error_t add_l3ip_interface(L3IP &l3ip, bool default_if, OnboardNetworkStack::Interface **interface_out) override;
 
     /** Register a PPP interface with the IP stack
      *
      * Connects PPP layer with the IP stack and initializes all the required infrastructure.
      * This function should be called only once for each available interface.
      *
      * This is an internal function that links ppp_lwip.cpp to mbed_ipstack_lwip.cpp,
      * once a driver starts it via the nsapi_ppp.h API.
      *
      * Ultimately the nsapi_ppp.h API will be deprecated, and there will be a
      * mbed_ipstack_add_ppp_interface() replacing nsapi_ppp_connect().
      *
      * @param      pcb              PPP implementation specific user data; will be passed to PPP callbacks
      * @param      default_if       true if the interface should be treated as the default one
      * @param      stack            Allow manual selection of IPv4 and/or IPv6
      * @param[out] interface_out    set to interface handle that must be passed to subsequent mbed_stack calls
      * @return                      NSAPI_ERROR_OK on success, or error code
      */
     nsapi_error_t add_ppp_interface(PPP &ppp, bool default_if, OnboardNetworkStack::Interface **interface_out) override;
 
     /** Remove a network interface from IP stack
      *
      * Removes layer 3 IP objects,network interface from stack list .
      * @param[out] interface_out    pointer to stack interface object controlling the EMAC
      * @return                      NSAPI_ERROR_OK on success, or error code
      */
     nsapi_error_t remove_ethernet_interface(OnboardNetworkStack::Interface **interface_out) override;
 
     /** Remove a network interface from IP stack
      *
      * Removes PPP objects,network interface from stack list, and shutdown device driver.
      * @param[out] interface_out    pointer to stack interface object controlling the PPP
      * @return                      NSAPI_ERROR_OK on success, or error code
      */
     nsapi_error_t remove_l3ip_interface(OnboardNetworkStack::Interface **interface_out) override;
 
     /** Remove a network interface from IP stack
      *
      * Removes PPP objects,network interface from stack list, and shutdown device driver.
      * @param[out] interface_out    pointer to stack interface object controlling the PPP
      * @return                      NSAPI_ERROR_OK on success, or error code
      */
     nsapi_error_t remove_ppp_interface(OnboardNetworkStack::Interface **interface_out) override;
 
     /** Get a domain name server from a list of servers to query
      *
      *  Returns a DNS server address for a index. If returns error no more
      *  DNS servers to read.
      *
      *  @param index    Index of the DNS server, starts from zero
      *  @param address  Destination for the host address
      *  @return         0 on success, negative error code on failure
      */
     nsapi_error_t get_dns_server(int index, SocketAddress *address, const char *interface_name) override;
 
     /** Add a domain name server to list of servers to query
      *
      *  @param address  Destination for the host address
      *  @param interface_name  Network interface name
      *  @return         NSAPI_ERROR_OK on success, negative error code on failure
      */
     nsapi_error_t add_dns_server(const SocketAddress &address, const char *interface_name) override;
 
     /** @copydoc NetworkStack::get_ip_address */
     nsapi_error_t get_ip_address(SocketAddress *address) override;
 
     /** @copydoc NetworkStack::get_ip_address_if */
     nsapi_error_t get_ip_address_if(SocketAddress *address, const char *interface_name) override;
 
     /** Set the network interface as default one
       */
     void set_default_interface(OnboardNetworkStack::Interface *interface) override;
 
 protected:
     LWIP();
 
     /** Opens a socket
      *
      *  Creates a network socket and stores it in the specified handle.
      *  The handle must be passed to following calls on the socket.
      *
      *  A stack may have a finite number of sockets, in this case
      *  NSAPI_ERROR_NO_SOCKET is returned if no socket is available.
      *
      *  @param handle   Destination for the handle to a newly created socket
      *  @param proto    Protocol of socket to open, NSAPI_TCP or NSAPI_UDP
      *  @return         0 on success, negative error code on failure
      */
     nsapi_error_t socket_open(nsapi_socket_t *handle, nsapi_protocol_t proto) override;
 
     /** Close the socket
      *
      *  Closes any open connection and deallocates any memory associated
      *  with the socket.
      *
      *  @param handle   Socket handle
      *  @return         0 on success, negative error code on failure
      */
     nsapi_error_t socket_close(nsapi_socket_t handle) override;
 
     /** Bind a specific address to a socket
      *
      *  Binding a socket specifies the address and port on which to recieve
      *  data. If the IP address is zeroed, only the port is bound.
      *
      *  @param handle   Socket handle
      *  @param address  Local address to bind
      *  @return         0 on success, negative error code on failure.
      */
     nsapi_error_t socket_bind(nsapi_socket_t handle, const SocketAddress &address) override;
 
     /** Listen for connections on a TCP socket
      *
      *  Marks the socket as a passive socket that can be used to accept
      *  incoming connections.
      *
      *  @param handle   Socket handle
      *  @param backlog  Number of pending connections that can be queued
      *                  simultaneously
      *  @return         0 on success, negative error code on failure
      */
     nsapi_error_t socket_listen(nsapi_socket_t handle, int backlog) override;
 
     /** Connects TCP socket to a remote host
      *
      *  Initiates a connection to a remote server specified by the
      *  indicated address.
      *
      *  @param handle   Socket handle
      *  @param address  The SocketAddress of the remote host
      *  @return         0 on success, negative error code on failure
      */
     nsapi_error_t socket_connect(nsapi_socket_t handle, const SocketAddress &address) override;
 
     /** Accepts a connection on a TCP socket
      *
      *  The server socket must be bound and set to listen for connections.
      *  On a new connection, creates a network socket and stores it in the
      *  specified handle. The handle must be passed to following calls on
      *  the socket.
      *
      *  A stack may have a finite number of sockets, in this case
      *  NSAPI_ERROR_NO_SOCKET is returned if no socket is available.
      *
      *  This call is non-blocking. If accept would block,
      *  NSAPI_ERROR_WOULD_BLOCK is returned immediately.
      *
      *  @param server   Socket handle to server to accept from
      *  @param handle   Destination for a handle to the newly created socket
      *  @param address  Destination for the remote address or NULL
      *  @return         0 on success, negative error code on failure
      */
     nsapi_error_t socket_accept(nsapi_socket_t server,
                                 nsapi_socket_t *handle, SocketAddress *address = 0) override;
 
     /** Send data over a TCP socket
      *
      *  The socket must be connected to a remote host. Returns the number of
      *  bytes sent from the buffer.
      *
      *  This call is non-blocking. If send would block,
      *  NSAPI_ERROR_WOULD_BLOCK is returned immediately.
      *
      *  @param handle   Socket handle
      *  @param data     Buffer of data to send to the host
      *  @param size     Size of the buffer in bytes
      *  @return         Number of sent bytes on success, negative error
      *                  code on failure
      */
     nsapi_size_or_error_t socket_send(nsapi_socket_t handle,
                                       const void *data, nsapi_size_t size) override;
 
     /** Receive data over a TCP socket
      *
      *  The socket must be connected to a remote host. Returns the number of
      *  bytes received into the buffer.
      *
      *  This call is non-blocking. If recv would block,
      *  NSAPI_ERROR_WOULD_BLOCK is returned immediately.
      *
      *  @param handle   Socket handle
      *  @param data     Destination buffer for data received from the host
      *  @param size     Size of the buffer in bytes
      *  @return         Number of received bytes on success, negative error
      *                  code on failure
      */
     nsapi_size_or_error_t socket_recv(nsapi_socket_t handle,
                                       void *data, nsapi_size_t size) override;
 
     /** Send a packet over a UDP socket
      *
      *  Sends data to the specified address. Returns the number of bytes
      *  sent from the buffer.
      *
      *  This call is non-blocking. If sendto would block,
      *  NSAPI_ERROR_WOULD_BLOCK is returned immediately.
      *
      *  @param handle   Socket handle
      *  @param address  The SocketAddress of the remote host
      *  @param data     Buffer of data to send to the host
      *  @param size     Size of the buffer in bytes
      *  @return         Number of sent bytes on success, negative error
      *                  code on failure
      */
     nsapi_size_or_error_t socket_sendto(nsapi_socket_t handle, const SocketAddress &address,
                                         const void *data, nsapi_size_t size) override;
 
     /** Receive a packet over a UDP socket
      *
      *  Receives data and stores the source address in address if address
      *  is not NULL. Returns the number of bytes received into the buffer.
      *
      *  This call is non-blocking. If recvfrom would block,
      *  NSAPI_ERROR_WOULD_BLOCK is returned immediately.
      *
      *  @param handle   Socket handle
      *  @param address  Destination for the source address or NULL
      *  @param buffer   Destination buffer for data received from the host
      *  @param size     Size of the buffer in bytes
      *  @return         Number of received bytes on success, negative error
      *                  code on failure
      */
     nsapi_size_or_error_t socket_recvfrom(nsapi_socket_t handle, SocketAddress *address,
                                           void *buffer, nsapi_size_t size) override;
 
     /** Register a callback on state change of the socket
      *
      *  The specified callback will be called on state changes such as when
      *  the socket can recv/send/accept successfully and on when an error
      *  occurs. The callback may also be called spuriously without reason.
      *
      *  The callback may be called in an interrupt context and should not
      *  perform expensive operations such as recv/send calls.
      *
      *  @param handle   Socket handle
      *  @param callback Function to call on state change
      *  @param data     Argument to pass to callback
      */
     void socket_attach(nsapi_socket_t handle, void (*callback)(void *), void *data) override;
 
     /*  Set stack-specific socket options
      *
      *  The setsockopt allow an application to pass stack-specific hints
      *  to the underlying stack. For unsupported options,
      *  NSAPI_ERROR_UNSUPPORTED is returned and the socket is unmodified.
      *
      *  @param handle   Socket handle
      *  @param level    Stack-specific protocol level
      *  @param optname  Stack-specific option identifier
      *  @param optval   Option value
      *  @param optlen   Length of the option value
      *  @return         0 on success, negative error code on failure
      */
     nsapi_error_t setsockopt(nsapi_socket_t handle, int level,
                              int optname, const void *optval, unsigned optlen) override;
 
     /*  Get stack-specific socket options
      *
      *  The getstackopt allow an application to retrieve stack-specific hints
      *  from the underlying stack. For unsupported options,
      *  NSAPI_ERROR_UNSUPPORTED is returned and optval is unmodified.
      *
      *  @param handle   Socket handle
      *  @param level    Stack-specific protocol level
      *  @param optname  Stack-specific option identifier
      *  @param optval   Destination for option value
      *  @param optlen   Length of the option value
      *  @return         0 on success, negative error code on failure
      */
     nsapi_error_t getsockopt(nsapi_socket_t handle, int level,
                              int optname, void *optval, unsigned *optlen) override;
 private:
 
     /** Call in callback
       *
       *  Callback is used to call the call in method of the network stack.
       */
     typedef mbed::Callback<nsapi_error_t (int delay_ms, mbed::Callback<void()> user_cb)> call_in_callback_cb_t;
 
     /** Get a call in callback
      *
      *  Get a call in callback from the network stack context.
      *
      *  Callback should not take more than 10ms to execute, otherwise it might
      *  prevent underlying thread processing. A portable user of the callback
      *  should not make calls to network operations due to stack size limitations.
      *  The callback should not perform expensive operations such as socket recv/send
      *  calls or blocking operations.
      *
      *  @return         Call in callback
      */
     call_in_callback_cb_t get_call_in_callback() override;
 
     /** Call a callback after a delay
      *
      *  Call a callback from the network stack context after a delay. If function
      *  returns error callback will not be called.
      *
      *  @param delay    Delay in milliseconds
      *  @param func     Callback to be called
      *  @return         0 on success, negative error code on failure
      */
     nsapi_error_t call_in(int delay, mbed::Callback<void()> func) override;
 
     struct mbed_lwip_socket {
         bool in_use;
 
         struct netconn *conn;
         struct pbuf *buf;
         u16_t offset;
 
         void (*cb)(void *);
         void *data;
 
         // Track multicast addresses subscribed to by this socket
         nsapi_ip_mreq_t *multicast_memberships;
         uint32_t         multicast_memberships_count;
         uint32_t         multicast_memberships_registry;
     };
 
     struct lwip_callback {
         unsigned int delay;
         mbed::Callback<void()> callback;
     };
 
     static nsapi_error_t err_remap(err_t err);
     static bool is_local_addr(const ip_addr_t *ip_addr);
     static const ip_addr_t *get_ip_addr(bool any_addr, const struct netif *netif);
     static const ip_addr_t *get_ipv4_addr(const struct netif *netif);
     static const ip_addr_t *get_ipv6_addr(const struct netif *netif);
     static const ip_addr_t *get_ipv6_link_local_addr(const struct netif *netif);
 
     static void add_dns_addr(struct netif *lwip_netif, const char *interface_name);
 
     /* Static arena of sockets */
     struct mbed_lwip_socket arena[MEMP_NUM_NETCONN];
     void arena_init(void);
     struct mbed_lwip_socket *arena_alloc();
     void arena_dealloc(struct mbed_lwip_socket *s);
 
     static uint32_t next_registered_multicast_member(const struct mbed_lwip_socket *s, uint32_t index)
     {
         while (!(s->multicast_memberships_registry & (0x0001 << index))) {
             index++;
         }
         return index;
     }
 
     static uint32_t next_free_multicast_member(const struct mbed_lwip_socket *s, uint32_t index)
     {
         while ((s->multicast_memberships_registry & (0x0001 << index))) {
             index++;
         }
         return index;
     }
 
     static void set_multicast_member_registry_bit(struct mbed_lwip_socket *s, uint32_t index)
     {
         s->multicast_memberships_registry |= (0x0001 << index);
     }
 
     static void clear_multicast_member_registry_bit(struct mbed_lwip_socket *s, uint32_t index)
     {
         s->multicast_memberships_registry &= ~(0x0001 << index);
     }
     static int32_t find_multicast_member(const struct mbed_lwip_socket *s, const nsapi_ip_mreq_t *imr);
 
     static void socket_callback(struct netconn *nc, enum netconn_evt eh, u16_t len);
 
     static void tcpip_init_irq(void *handle);
     static void tcpip_thread_callback(void *ptr);
 
     char ip_address[40];
     Interface *default_interface;
     LWIPMemoryManager memory_manager;
     osThreadId tcpip_thread_id;
     rtos::Mutex adaptation;
     rtos::EventFlags _event_flag;
     static const int TCP_CLOSED_FLAG = 0x4u;
 };
 
 #endif /* LWIPSTACK_H_ */
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