VSocket Use Cases

Using Virtual Socket Interface (VSocket)

Using Virtual Socket Interface (VSocket)

VSocket API provides a general purpose implementation for socket peripheral. This chapter shows how VSocket can be applied in specific use case.

./interface/vsocket/iot_socket.c: implements the IoT Socket variant for Arm Virtual Hardware based on the ARM_VSocket_Type structure and its mapping defined in arm_vsocket.h.

Setup

Instructions below cover specifically setup for using IoT Socket API in a project using Arm Fixed Virtual Platform (FVP) as a target.

• Verify that following packs are installed in your development environment:
  • ARM::CMSIS pack for access to CMSIS-RTOS2 API used by VSocket implementation.
  • IoT Socket pack for access to IoT Socket API header (iot_socket.h)
  • Pack with target device support for access to VSocket API (arm_vsocket.h)
• Select Virtual Hardware device as the target in the project. See in Using AVH FVPs.
• Following components shall be selected as part of the project:
  • CMSIS:CORE for general device abstraction
  • CMSIS:RTOS2 (API) for RTOS2 API,
  • IoT Utility:Socket (API):Custom component that provides access to iot_socket.h file.
• Copy ./interface/vsocket/iot_socket.c file to your local project folder and add it to the project.

Note that VSocket does not require Semihosting to be enabled on the FVP model.

Usage example

After VSocket is added to the project the interface can be fully used as described in IoT Socket documentation. For example:

#include "iot_socket.h"                  // ::IoT Utility:Socket (API)
static const char message[] = { "The quick brown fox jumps over the lazy dog." };
 
void Echo_Client_Thread (void *arg) {
  uint8_t ip[4] = { 192U, 168U, 0U, 100U };
  int32_t sock, res;
  char dbuf[120];
 
  while (1) {
    sock = iotSocketCreate (IOT_SOCKET_AF_INET, IOT_SOCKET_SOCK_STREAM, IOT_SOCKET_IPPROTO_TCP);
 
    res = iotSocketConnect (sock, (uint8_t *)ip, sizeof(ip), 7U);
    if (res == 0) {
      while (1) {
        iotSocketSend (sock, message, sizeof(message));
        res = iotSocketRecv (sock, dbuf, sizeof(dbuf));
        if (res < 0) {
          break;               // Receive error
        }
        if (res > 0) {
          if (memcmp (dbuf, message, res) != 0) {
            break;             // Message error, echoed message is not the same
          }
        }
        osDelay (1000U);
      }
    }
    iotSocketClose (sock);
  }
}