Linux / C++ - Vsock 예제 (Hyper-V Socket 연동)

지난 글에서 작성한 C#과 유사한 예제를, C/C++로 만들면 다음과 같습니다.

#include <cstdio>
#include <sys/socket.h>
#include <linux/vm_sockets.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>

void RunAsServer(unsigned int cid, unsigned int port)
{
    int server_socket = socket(AF_VSOCK, SOCK_STREAM, 0);

    sockaddr_vm sv = { 0 };
    sv.svm_family = AF_VSOCK;
    sv.svm_cid = cid;
    sv.svm_port = port;

    do
    {
        int result = bind(server_socket, (sockaddr*)&sv, sizeof(sockaddr_vm));
        if (result != 0)
        {
            printf("bind failed!\n");
            break;
        }

        listen(server_socket, 5);

        while (true)
        {
            int client_socket = accept(server_socket, nullptr, nullptr);
            if (client_socket < 0)
            {
                printf("accept failed!\n");
                break;
            }

            printf("connected: %d\n", client_socket);
            char buffer[1024] = { 0 };
            recv(client_socket, buffer, 1024, 0);
            
            strcpy(buffer + 7, buffer);
            strcpy(buffer, "Hello:");
            buffer[6] = ' ';
            
            send(client_socket, buffer, strlen(buffer), 0);

            close(client_socket);
        }

    } while (false);

    close(server_socket);
}

void RunAsClient(unsigned int cid, unsigned int port)
{
    int stream_socket = socket(AF_VSOCK, SOCK_STREAM, 0);

    sockaddr_vm sv = { 0 };
    sv.svm_family = AF_VSOCK;
    sv.svm_cid = cid;
    sv.svm_port = port;

    int connected = connect(stream_socket, (sockaddr*)&sv, sizeof(sockaddr_vm));

    printf("socket = %d, connected = %d, size = %d!\n", stream_socket, connected, sizeof(sockaddr_vm));
    send(stream_socket, "Hello", 6, 0);

    char buffer[1024] = { 0 };
    recv(stream_socket, buffer, 1024, 0);
    printf("recv: %s\n", buffer);

    close(stream_socket);
}

int main(int argc, char** args)
{
    unsigned int cid = VMADDR_PORT_ANY;
    unsigned int port = 19000;

    int socket_mode = 0;

    if (argc >= 2)
    {
        char* mode = args[1];
        if (strcmp(mode, "/server") == 0)
        {
            socket_mode = 0;
        }
        else if (strcmp(mode, "/client") == 0)
        {
            socket_mode = 1;
        }
    }

    if (argc >= 3)
    {
        char* cid_str = args[2];
        if (strcmp(cid_str, "any") == 0 || 
            strcmp(cid_str, "wildcard") == 0)
        {
            cid = VMADDR_CID_ANY;
        }
        else if (strcmp(cid_str, "lo") == 0 ||
            strcmp(cid_str, "loopback") == 0)
        {
            cid = VMADDR_CID_LOCAL;
        }
        else if (strcmp(cid_str, "host") == 0 ||
            strcmp(cid_str, "parent") == 0)
        {
            cid = VMADDR_CID_HOST;
        }
        else if (strcmp(cid_str, "hypervisor") == 0 ||
            strcmp(cid_str, "hv") == 0)
        {
            cid = VMADDR_CID_HYPERVISOR;
        }
    }

    if (argc >= 4)
    {
        char* port_str = args[3];
        port = atoi(port_str);
    }

    if (socket_mode == 0)
    {
        RunAsServer(cid, port);
    }
    else
    {
        RunAsClient(cid, port);
    }

    return 0;
}

// Linux VM에서 실행

$ ./ConsoleApplication1.out /server lo

// Linux VM의 ID가 "f952c5ef-ea6c-4c83-b52c-38f31cf68b61"로 가정

c:\temp> ConsoleApp1.exe /client f952c5ef-ea6c-4c83-b52c-38f31cf68b61

c:\temp> ConsoleApp1.exe /server /lo

$ ./ConsoleApplication1.out /client parent