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 I/O 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);
  }
}