Mbed OS Reference | nsapi_types.h Source File

 
 /** \addtogroup netsocket */
 /** @{*/
 /* nsapi.h - The network socket API
  * Copyright (c) 2015 ARM Limited
  * SPDX-License-Identifier: Apache-2.0
  *
  * 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 NSAPI_TYPES_H
 #define NSAPI_TYPES_H
 
 #include <stdint.h>
 #include <stddef.h>
 #include "mbed_toolchain.h"
 
 #ifdef __cplusplus
 extern "C" {
 #endif
 
 
 /*
  * The Type of Service provides an indication of the abstract
  * parameters of the quality of service desired.  These parameters are
  * to be used to guide the selection of the actual service parameters
  * when transmitting a datagram through a particular network.  Several
  * networks offer service precedence, which somehow treats high
  * precedence traffic as more important than other traffic (generally
  * by accepting only traffic above a certain precedence at time of high
  * load).  The major choice is a three way tradeoff between low-delay,
  * high-reliability, and high-throughput.
  * The use of the Delay, Throughput, and Reliability indications may
  * increase the cost (in some sense) of the service.  In many networks
  * better performance for one of these parameters is coupled with worse
  * performance on another.  Except for very unusual cases at most two
  * of these three indications should be set.
  */
 #define NSAPI_IPTOS_TOS_MASK          0x1E
 #define NSAPI_IPTOS_TOS(tos)          ((tos) & IPTOS_TOS_MASK)
 #define NSAPI_IPTOS_LOWDELAY          0x10
 #define NSAPI_IPTOS_THROUGHPUT        0x08
 #define NSAPI_IPTOS_RELIABILITY       0x04
 #define NSAPI_IPTOS_LOWCOST           0x02
 #define NSAPI_IPTOS_MINCOST           IPTOS_LOWCOST
 
 /*
  * The Network Control precedence designation is intended to be used
  * within a network only.  The actual use and control of that
  * designation is up to each network. The Internetwork Control
  * designation is intended for use by gateway control originators only.
  * If the actual use of these precedence designations is of concern to
  * a particular network, it is the responsibility of that network to
  * control the access to, and use of, those precedence designations.
  */
 #define NSAPI_IPTOS_PREC_MASK                 0xe0
 #define NSAPI_IPTOS_PREC(tos)                ((tos) & IPTOS_PREC_MASK)
 #define NSAPI_IPTOS_PREC_NETCONTROL           0xe0
 #define NSAPI_IPTOS_PREC_INTERNETCONTROL      0xc0
 #define NSAPI_IPTOS_PREC_CRITIC_ECP           0xa0
 #define NSAPI_IPTOS_PREC_FLASHOVERRIDE        0x80
 #define NSAPI_IPTOS_PREC_FLASH                0x60
 #define NSAPI_IPTOS_PREC_IMMEDIATE            0x40
 #define NSAPI_IPTOS_PREC_PRIORITY             0x20
 #define NSAPI_IPTOS_PREC_ROUTINE              0x00
 
 /** Enum of standardized error codes
  *
  *  Valid error codes have negative values and may
  *  be returned by any network operation.
  *
  *  @enum nsapi_error
  */
 enum nsapi_error {
     NSAPI_ERROR_OK                  =  0,        /*!< no error */
     NSAPI_ERROR_WOULD_BLOCK         = -3001,     /*!< no data is not available but call is non-blocking */
     NSAPI_ERROR_UNSUPPORTED         = -3002,     /*!< unsupported functionality */
     NSAPI_ERROR_PARAMETER           = -3003,     /*!< invalid configuration */
     NSAPI_ERROR_NO_CONNECTION       = -3004,     /*!< not connected to a network */
     NSAPI_ERROR_NO_SOCKET           = -3005,     /*!< socket not available for use */
     NSAPI_ERROR_NO_ADDRESS          = -3006,     /*!< IP address is not known */
     NSAPI_ERROR_NO_MEMORY           = -3007,     /*!< memory resource not available */
     NSAPI_ERROR_NO_SSID             = -3008,     /*!< ssid not found */
     NSAPI_ERROR_DNS_FAILURE         = -3009,     /*!< DNS failed to complete successfully */
     NSAPI_ERROR_DHCP_FAILURE        = -3010,     /*!< DHCP failed to complete successfully */
     NSAPI_ERROR_AUTH_FAILURE        = -3011,     /*!< connection to access point failed */
     NSAPI_ERROR_DEVICE_ERROR        = -3012,     /*!< failure interfacing with the network processor */
     NSAPI_ERROR_IN_PROGRESS         = -3013,     /*!< operation (eg connect) in progress */
     NSAPI_ERROR_ALREADY             = -3014,     /*!< operation (eg connect) already in progress */
     NSAPI_ERROR_IS_CONNECTED        = -3015,     /*!< socket is already connected */
     NSAPI_ERROR_CONNECTION_LOST     = -3016,     /*!< connection lost */
     NSAPI_ERROR_CONNECTION_TIMEOUT  = -3017,     /*!< connection timed out */
     NSAPI_ERROR_ADDRESS_IN_USE      = -3018,     /*!< Address already in use */
     NSAPI_ERROR_TIMEOUT             = -3019,     /*!< operation timed out */
     NSAPI_ERROR_BUSY                = -3020,     /*!< device is busy and cannot accept new operation */
 };
 
 
 /** Enum of connection status types
  *
  *  Valid error codes have negative values.
  *
  *  @enum nsapi_connection_status
  */
 typedef enum nsapi_connection_status {
     NSAPI_STATUS_LOCAL_UP           = 0,        /*!< local IP address set */
     NSAPI_STATUS_GLOBAL_UP          = 1,        /*!< global IP address set */
     NSAPI_STATUS_DISCONNECTED       = 2,        /*!< no connection to network */
     NSAPI_STATUS_CONNECTING         = 3,        /*!< connecting to network */
     NSAPI_STATUS_ERROR_UNSUPPORTED  = NSAPI_ERROR_UNSUPPORTED
 } nsapi_connection_status_t;
 
 
 /** Enum of event types
  *
  *  Event callbacks are accompanied with an event-dependent parameter passed as an intptr_t.
  *
  *  @enum nsapi_event
  */
 typedef enum nsapi_event {
     NSAPI_EVENT_CONNECTION_STATUS_CHANGE = 0, /*!< network connection status has changed, the parameter = new status (nsapi_connection_status_t) */
     NSAPI_EVENT_CELLULAR_STATUS_BASE     = 0x1000,  /*!< Cellular modem status has changed, See the enum values from enum cellular_connection_status_t in /connectivity/cellular/framework/common/CellularCommon.h */
     NSAPI_EVENT_CELLULAR_STATUS_END      = 0x1FFF   /*!< cellular modem status has changed, See the enum values from enum cellular_connection_status_t in /connectivity/cellular/framework/common/CellularCommon.h */
 } nsapi_event_t;
 
 
 /** Type used to represent error codes
  *
  *  This is a separate type from enum nsapi_error to avoid breaking
  *  compatibility in type-sensitive overloads
  */
 typedef signed int nsapi_error_t;
 
 /** Type used to represent the size of data passed through sockets
  */
 typedef unsigned int nsapi_size_t;
 
 /** Type used to represent either a size or error passed through sockets
  *
  *  A valid nsapi_size_or_error_t is either a non-negative size or a
  *  negative error code from the nsapi_error_t
  */
 typedef signed int nsapi_size_or_error_t;
 
 /** Type used to represent either a value or error
  *
  *  A valid nsapi_value_or_error_t is either a non-negative value or a
  *  negative error code from the nsapi_error_t
  */
 typedef signed int nsapi_value_or_error_t;
 
 /** Enum of encryption types
  *
  *  The security type specifies a particular security to use when
  *  connected to a WiFi network
  */
 typedef enum nsapi_security {
     NSAPI_SECURITY_NONE         = 0x0,      /*!< open access point */
     NSAPI_SECURITY_WEP          = 0x1,      /*!< phrase conforms to WEP */
     NSAPI_SECURITY_WPA          = 0x2,      /*!< phrase conforms to WPA */
     NSAPI_SECURITY_WPA2         = 0x3,      /*!< phrase conforms to WPA2 */
     NSAPI_SECURITY_WPA_WPA2     = 0x4,      /*!< phrase conforms to WPA/WPA2 */
     NSAPI_SECURITY_PAP          = 0x5,      /*!< phrase conforms to PPP authentication context */
     NSAPI_SECURITY_CHAP         = 0x6,      /*!< phrase conforms to PPP authentication context */
     NSAPI_SECURITY_EAP_TLS      = 0x7,      /*!< phrase conforms to EAP-TLS */
     NSAPI_SECURITY_PEAP         = 0x8,      /*!< phrase conforms to PEAP */
     NSAPI_SECURITY_WPA2_ENT     = 0x9,      /*!< phrase conforms to WPA2-AES and WPA-TKIP with enterprise security */
     NSAPI_SECURITY_WPA3         = 0xA,      /*!< phrase conforms to WPA3 */
     NSAPI_SECURITY_WPA3_WPA2    = 0xB,      /*!< phrase conforms to WPA3_WPA2 */
     NSAPI_SECURITY_UNKNOWN      = 0xFF,     /*!< unknown/unsupported security in scan results */
 } nsapi_security_t;
 
 /** Size of  2 char network interface name from driver
  */
 #define NSAPI_INTERFACE_PREFIX_SIZE 2
 
 /** Maximum size of network interface name
  */
 #define NSAPI_INTERFACE_NAME_MAX_SIZE 6
 
 /** Maximum size of IP address representation
  */
 #define NSAPI_IP_SIZE NSAPI_IPv6_SIZE
 
 /** Maximum number of bytes for IP address
  */
 #define NSAPI_IP_BYTES NSAPI_IPv6_BYTES
 
 /** Maximum size of MAC address representation
  */
 #define NSAPI_MAC_SIZE 18
 
 /** Maximum number of bytes for MAC address
  */
 #define NSAPI_MAC_BYTES 6
 
 /** Size of IPv4 representation
  */
 #define NSAPI_IPv4_SIZE 16
 
 /** Number of bytes in IPv4 address
  */
 #define NSAPI_IPv4_BYTES 4
 
 /** Size of IPv6 representation
  */
 #define NSAPI_IPv6_SIZE 40
 
 /** Number of bytes in IPv6 address
  */
 #define NSAPI_IPv6_BYTES 16
 
 /** Enum of IP address versions
  *
  *  The IP version specifies the type of an IP address.
  *
  *  @enum nsapi_version
  */
 typedef enum nsapi_version {
     NSAPI_UNSPEC,   /*!< Address is unspecified */
     NSAPI_IPv4,     /*!< Address is IPv4 */
     NSAPI_IPv6,     /*!< Address is IPv6 */
 } nsapi_version_t;
 
 /** IP address structure for passing IP addresses by value
  */
 typedef struct nsapi_addr {
     /** IP version
      *  - NSAPI_IPv4
      *  - NSAPI_IPv6
      *  - NSAPI_UNSPEC
      */
     nsapi_version_t version;
 
     /** IP address
      *  The raw bytes of the IP address stored in big-endian format
      */
     uint8_t bytes[NSAPI_IP_BYTES];
 } nsapi_addr_t;
 
 
 /** Opaque handle for network sockets
  */
 typedef void *nsapi_socket_t;
 
 
 /** Enum of socket protocols
  *
  *  The socket protocol specifies a particular protocol to
  *  be used with a newly created socket.
  *
  *  @enum nsapi_protocol
  */
 typedef enum nsapi_protocol {
     NSAPI_TCP, /*!< Socket is of TCP type */
     NSAPI_UDP, /*!< Socket is of UDP type */
     NSAPI_ICMP, /*!< Socket is of ICMP type */
 } nsapi_protocol_t;
 
 /** Enum of standardized stack option levels
  *  for use with NetworkStack::setstackopt and getstackopt.
  *
  *  @enum nsapi_stack_level
  */
 typedef enum nsapi_stack_level {
     NSAPI_STACK     = 5000, /*!< Stack option level - see nsapi_stack_option_t for options */
 } nsapi_stack_level_t;
 
 /** Enum of standardized stack option names for level NSAPI_STACK
  *  of NetworkStack::setstackopt and getstackopt.
  *
  *  These options may not be supported on all stacks, in which
  *  case NSAPI_ERROR_UNSUPPORTED may be returned.
  *
  *  @enum nsapi_stack_option
  */
 typedef enum nsapi_stack_option {
     NSAPI_IPV4_MRU, /*!< Sets/gets size of largest IPv4 fragmented datagram to reassemble */
     NSAPI_IPV6_MRU, /*!< Sets/gets size of largest IPv6 fragmented datagram to reassemble */
 } nsapi_stack_option_t;
 
 /** Enum of standardized socket option levels
  *  for use with Socket::setsockopt and getsockopt.
  *
  *  @enum nsapi_socket_level
  */
 typedef enum nsapi_socket_level {
     NSAPI_SOCKET    = 7000, /*!< Socket option level - see nsapi_socket_option_t for options */
 } nsapi_socket_level_t;
 
 /** Enum of standardized socket option names for level NSAPI_SOCKET
  *  of Socket::setsockopt and getsockopt.
  *
  *  These options may not be supported on all stacks, in which
  *  case NSAPI_ERROR_UNSUPPORTED may be returned.
  *
  *  @enum nsapi_socket_option
  */
 typedef enum nsapi_socket_option {
     NSAPI_REUSEADDR,         /*!< Allow bind to reuse local addresses */
     NSAPI_KEEPALIVE,         /*!< Enables sending of keepalive messages */
     NSAPI_KEEPIDLE,          /*!< Sets timeout value to initiate keepalive */
     NSAPI_KEEPINTVL,         /*!< Sets timeout value for keepalive */
     NSAPI_LINGER,            /*!< Keeps close from returning until queues empty */
     NSAPI_SNDBUF,            /*!< Sets send buffer size */
     NSAPI_RCVBUF,            /*!< Sets recv buffer size */
     NSAPI_ADD_MEMBERSHIP,    /*!< Add membership to multicast address */
     NSAPI_DROP_MEMBERSHIP,   /*!< Drop membership to multicast address */
     NSAPI_BIND_TO_DEVICE,    /*!< Bind socket network interface name*/
     NSAPI_LATENCY,           /*!< Read estimated latency to destination */
     NSAPI_STAGGER,           /*!< Read estimated stagger value to destination */
     NSAPI_IPTOS,             /*!< Set IP type of service to set specific precedence */
     NSAPI_BROADCAST,         /*!< Set broadcast flag for UDP socket */
     NSAPI_PKTINFO            /*!< Get additional information when using sendto_control/recvfrom_control */
 } nsapi_socket_option_t;
 
 typedef enum nsapi_tlssocket_level {
     NSAPI_TLSSOCKET_LEVEL   = 7099, /*!< TLSSocket option level - see nsapi_tlssocket_option_t for options*/
 } nsapi_tlssocket_level_t;
 
 typedef enum nsapi_tlssocket_option {
     NSAPI_TLSSOCKET_SET_HOSTNAME,   /*!< Set host name */
     NSAPI_TLSSOCKET_SET_CACERT,     /*!< Set server CA certificate */
     NSAPI_TLSSOCKET_SET_CLCERT,     /*!< Set client certificate */
     NSAPI_TLSSOCKET_SET_CLKEY,      /*!< Set client key */
     NSAPI_TLSSOCKET_ENABLE          /*!< Enable TLSSocket */
 } nsapi_tlssocket_option_t;
 
 /** Supported IP protocol versions of IP stack
  *
  *  @enum nsapi_ip_stack
  */
 typedef enum nsapi_ip_stack {
     DEFAULT_STACK = 0,
     IPV4_STACK,
     IPV6_STACK,
     IPV4V6_STACK
 } nsapi_ip_stack_t;
 
 /* Backwards compatibility - previously didn't distinguish stack and socket options */
 typedef nsapi_socket_level_t nsapi_level_t;
 typedef nsapi_socket_option_t nsapi_option_t;
 
 /** nsapi_wifi_ap structure
  *
  *  Structure representing a WiFi Access Point
  */
 typedef struct nsapi_wifi_ap {
     char ssid[33]; /* 32 is what 802.11 defines as longest possible name; +1 for the \0 */
     uint8_t bssid[6];
     nsapi_security_t security;
     int8_t rssi;
     uint8_t channel;
 } nsapi_wifi_ap_t;
 
 
 /** nsapi_stack structure
  *
  *  Stack structure representing a specific instance of a stack.
  */
 typedef struct nsapi_stack {
     /** Network stack operation table
      *
      *  Provides access to the underlying api of the stack. This is not
      *  flattened into the nsapi_stack to allow allocation in read-only
      *  memory.
      */
     const struct nsapi_stack_api *stack_api;
 
     /** Opaque handle for network stacks
      */
     void *stack;
 
     // Internal nsapi buffer
     unsigned _stack_buffer[16];
 } nsapi_stack_t;
 
 /** nsapi_ip_mreq structure
  */
 typedef struct nsapi_ip_mreq {
     nsapi_addr_t imr_multiaddr; /* IP multicast address of group */
     nsapi_addr_t imr_interface; /* local IP address of interface */
 } nsapi_ip_mreq_t;
 
 /** nsapi_latency_req structure
  */
 typedef struct nsapi_latency_req {
     uint8_t addr[16];   /* [IN] Destination address to estimate latency */
     uint32_t latency;   /* [OUT] Latency value */
 } nsapi_latency_req_t;
 
 /** nsapi_stagger_req structure
  */
 typedef struct nsapi_stagger_req {
     uint8_t addr[16];       /* [IN] Destination address to estimate stagger */
     uint16_t data_amount;   /* [IN] Amount of data to be sent in kilobytes */
     uint16_t stagger_min;   /* [OUT] Minimum stagger value in seconds */
     uint16_t stagger_max;   /* [OUT] Maximum stagger value in seconds */
     uint16_t stagger_rand;  /* [OUT] Randomized stagger value in seconds */
 } nsapi_stagger_req_t;
 
 /** nsapi_msghdr
  */
 typedef struct nsapi_msghdr {
     /* In C alignment can't be specified in the type declaration.
      * Specifying it in the first member definition will affect whole structure.
      */
     MBED_ALIGN(max_align_t) nsapi_size_t len;    /* Data byte count, including header */
     int          level;  /* Originating protocol */
     int          type;   /* Protocol-specific type */
 } nsapi_msghdr_t;
 
 /** nsapi_pktinfo structure
  */
 typedef struct nsapi_pktinfo {
     nsapi_msghdr_t hdr;         /* Header identifying the message control structure */
     nsapi_addr_t   ipi_addr;    /* Address associated with the packet */
     int            ipi_ifindex; /* Interface associated with the packet */
     void          *network_interface; /* Network interface pointer*/
 } nsapi_pktinfo_t;
 
 /** nsapi_stack_api structure
  *
  *  Common api structure for network stack operations. A network stack
  *  can provide a nsapi_stack_api structure filled out with the
  *  appropriate implementation.
  *
  *  Unsupported operations can be left as null pointers.
  */
 typedef struct nsapi_stack_api {
     /** Get the local IP address
      *
      *  @param stack    Stack handle
      *  @return         Local IP Address or null address if not connected
      */
     nsapi_addr_t (*get_ip_address)(nsapi_stack_t *stack);
 
     /** Translates a hostname to an IP address
      *
      *  The hostname may be either a domain name or an IP address. If the
      *  hostname is an IP address, no network transactions will be performed.
      *
      *  If no stack-specific DNS resolution is provided, the hostname
      *  will be resolve using a UDP socket on the stack.
      *
      *  @param stack    Stack handle
      *  @param addr     Destination for the host IP address
      *  @param host     Hostname to resolve
      *  @param version  Address family
      *  @return         0 on success, negative error code on failure
      */
     nsapi_error_t (*gethostbyname)(nsapi_stack_t *stack, const char *host, nsapi_addr_t *addr, nsapi_version_t version);
 
     /** Add a domain name server to list of servers to query
      *
      *  @param addr     Destination for the host address
      *  @return         0 on success, negative error code on failure
      */
     nsapi_error_t (*add_dns_server)(nsapi_stack_t *stack, nsapi_addr_t addr);
 
     /** Set stack-specific stack options
      *
      *  The setstackopt allow an application to pass stack-specific hints
      *  to the underlying stack. For unsupported options,
      *  NSAPI_ERROR_UNSUPPORTED is returned and the stack is unmodified.
      *
      *  @param stack    Stack 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 (*setstackopt)(nsapi_stack_t *stack, int level,
                                  int optname, const void *optval, unsigned optlen);
 
     /** Get stack-specific stack 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 stack    Stack 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 (*getstackopt)(nsapi_stack_t *stack, int level,
                                  int optname, void *optval, unsigned *optlen);
 
     /** 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 stack    Stack context
      *  @param socket   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_stack_t *stack, nsapi_socket_t *socket,
                                  nsapi_protocol_t proto);
 
     /** Close the socket
      *
      *  Closes any open connection and deallocates any memory associated
      *  with the socket.
      *
      *  @param stack    Stack handle
      *  @param socket   Socket handle
      *  @return         0 on success, negative error code on failure
      */
     nsapi_error_t (*socket_close)(nsapi_stack_t *stack, nsapi_socket_t socket);
 
     /** Bind a specific address to a socket
      *
      *  Binding a socket specifies the address and port on which to receive
      *  data. If the IP address is zeroed, only the port is bound.
      *
      *  @param stack    Stack handle
      *  @param socket   Socket handle
      *  @param addr     Local address to bind, may be null
      *  @param port     Local port to bind
      *  @return         0 on success, negative error code on failure.
      */
     nsapi_error_t (*socket_bind)(nsapi_stack_t *stack, nsapi_socket_t socket,
                                  nsapi_addr_t addr, uint16_t port);
 
     /** Listen for connections on a TCP socket
      *
      *  Marks the socket as a passive socket that can be used to accept
      *  incoming connections.
      *
      *  @param stack    Stack handle
      *  @param socket   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_stack_t *stack, nsapi_socket_t socket, int backlog);
 
     /** Connects TCP socket to a remote host
      *
      *  Initiates a connection to a remote server specified by the
      *  indicated address.
      *
      *  @param stack    Stack handle
      *  @param socket   Socket handle
      *  @param addr     The address of the remote host
      *  @param port     The port of the remote host
      *  @return         0 on success, negative error code on failure
      */
     nsapi_error_t (*socket_connect)(nsapi_stack_t *stack, nsapi_socket_t socket,
                                     nsapi_addr_t addr, uint16_t port);
 
     /** 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 stack    Stack handle
      *  @param server   Socket handle to server to accept from
      *  @param socket   Destination for a handle to the newly created socket
      *  @param addr     Destination for the address of the remote host
      *  @param port     Destination for the port of the remote host
      *  @return         0 on success, negative error code on failure
      */
     nsapi_error_t (*socket_accept)(nsapi_stack_t *stack, nsapi_socket_t server,
                                    nsapi_socket_t *socket, nsapi_addr_t *addr, uint16_t *port);
 
     /** 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 stack    Stack handle
      *  @param socket   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_stack_t *stack, nsapi_socket_t socket,
                                          const void *data, nsapi_size_t size);
 
     /** 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 stack    Stack handle
      *  @param socket   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_stack_t *stack, nsapi_socket_t socket,
                                          void *data, nsapi_size_t size);
 
     /** 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 stack    Stack handle
      *  @param socket   Socket handle
      *  @param addr     The address of the remote host
      *  @param port     The port 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_stack_t *stack, nsapi_socket_t socket,
                                            nsapi_addr_t addr, uint16_t port, const void *data, nsapi_size_t size);
 
     /** 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 stack    Stack handle
      *  @param socket   Socket handle
      *  @param addr     Destination for the address of the remote host
      *  @param port     Destination for the port of the remote host
      *  @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_recvfrom)(nsapi_stack_t *stack, nsapi_socket_t socket,
                                              nsapi_addr_t *addr, uint16_t *port, void *buffer, nsapi_size_t size);
 
     // TODO: Documentation
     nsapi_size_or_error_t (*socket_sendto_control)(nsapi_stack_t *stack, nsapi_socket_t socket,
                                                    nsapi_addr_t addr, uint16_t port,
                                                    const void *data, nsapi_size_t size,
                                                    const nsapi_msghdr_t *control, nsapi_size_t control_size);
 
     nsapi_size_or_error_t (*socket_recvfrom_control)(nsapi_stack_t *stack, nsapi_socket_t socket,
                                                      nsapi_addr_t *addr, uint16_t *port,
                                                      void *data, nsapi_size_t size,
                                                      nsapi_msghdr_t *control, nsapi_size_t control_size);
 
     /** 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 stack    Stack handle
      *  @param socket   Socket handle
      *  @param callback Function to call on state change
      *  @param data     Argument to pass to callback
      */
     void (*socket_attach)(nsapi_stack_t *stack, nsapi_socket_t socket,
                           void (*callback)(void *), void *data);
 
     /** 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 stack    Stack handle
      *  @param socket   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_stack_t *stack, nsapi_socket_t socket, int level,
                                 int optname, const void *optval, unsigned optlen);
 
     /** 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 stack    Stack handle
      *  @param socket   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_stack_t *stack, nsapi_socket_t socket, int level,
                                 int optname, void *optval, unsigned *optlen);
 } nsapi_stack_api_t;
 
 
 #ifdef __cplusplus
 }
 #endif
 
 #endif
 
 /** @}*/
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