vsock 介绍与使用

vsock介绍

vsock 使用

内核配置

虚拟机kernel

将下面三个选项编译进kernel，而不是编译成模块，原因下面会介绍

CONFIG_VSOCKETS=y
CONFIG_VIRTIO_VSOCKETS=y
CONFIG_VIRTIO_VSOCKETS_COMMON=y

宿主机kernel

VHOST_VSOCK 只能够被编译成模块

CONFIG_VHOST_VSOCK=m

使用QEMU启动虚拟机

modprobe vhost_vsock

示例程序

Server (运行在宿主机上)

#include <sys/socket.h>
#include <linux/vm_sockets.h>
#include <string.h>
#include <stdio.h>

int main()
{
    int s = socket(AF_VSOCK, SOCK_STREAM, 0);

    struct sockaddr_vm addr;
    memset(&addr, 0, sizeof(struct sockaddr_vm));
    addr.svm_family = AF_VSOCK;
    addr.svm_port = 9999;
    addr.svm_cid = VMADDR_CID_HOST;

    bind(s, &addr, sizeof(struct sockaddr_vm));

    listen(s, 0);

    struct sockaddr_vm peer_addr;
    socklen_t peer_addr_size = sizeof(struct sockaddr_vm);
    int peer_fd = accept(s, &peer_addr, &peer_addr_size);

    char buf[64];
    size_t msg_len;
    while ((msg_len = recv(peer_fd, &buf, 64, 0)) > 0) {
        printf("Received %lu bytes: %.*s\n", msg_len, msg_len, buf);
    }

    return 0;
}

Client (运行在虚拟机上)

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

int main()
{
    int s = socket(AF_VSOCK, SOCK_STREAM, 0);

    struct sockaddr_vm addr;
    memset(&addr, 0, sizeof(struct sockaddr_vm));
    addr.svm_family = AF_VSOCK;
    addr.svm_port = 9999;
    addr.svm_cid = VMADDR_CID_HOST;

    connect(s, &addr, sizeof(struct sockaddr_vm));

    send(s, "Hello, world!", 13, 0);

    close(s);

    return 0;
}

参考

https://gist.github.com/nrdmn/7971be650919b112343b1cb2757a3fe6

https://wiki.qemu.org/Features/VirtioVsock

https://lwn.net/Articles/556550/