WSL2-Linux-Kernel/arch/um/drivers/slirp_kern.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (C) 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
 */

#include <linux/if_arp.h>
#include <linux/init.h>
#include <linux/netdevice.h>
#include <linux/string.h>
#include <net_kern.h>
#include <net_user.h>
#include "slirp.h"

struct slirp_init {
	struct arg_list_dummy_wrapper argw;  /* XXX should be simpler... */
};

void slirp_init(struct net_device *dev, void *data)
{
	struct uml_net_private *private;
	struct slirp_data *spri;
	struct slirp_init *init = data;
	int i;

	private = netdev_priv(dev);
	spri = (struct slirp_data *) private->user;

	spri->argw = init->argw;
	spri->pid = -1;
	spri->slave = -1;
	spri->dev = dev;

	slip_proto_init(&spri->slip);

	dev->hard_header_len = 0;
	dev->header_ops = NULL;
	dev->addr_len = 0;
	dev->type = ARPHRD_SLIP;
	dev->tx_queue_len = 256;
	dev->flags = IFF_NOARP;
	printk("SLIRP backend - command line:");
	for (i = 0; spri->argw.argv[i] != NULL; i++)
		printk(" '%s'",spri->argw.argv[i]);
	printk("\n");
}

static unsigned short slirp_protocol(struct sk_buff *skbuff)
{
	return htons(ETH_P_IP);
}

static int slirp_read(int fd, struct sk_buff *skb, struct uml_net_private *lp)
{
	return slirp_user_read(fd, skb_mac_header(skb), skb->dev->mtu,
			       (struct slirp_data *) &lp->user);
}

static int slirp_write(int fd, struct sk_buff *skb, struct uml_net_private *lp)
{
	return slirp_user_write(fd, skb->data, skb->len,
				(struct slirp_data *) &lp->user);
}

const struct net_kern_info slirp_kern_info = {
	.init			= slirp_init,
	.protocol		= slirp_protocol,
	.read			= slirp_read,
	.write			= slirp_write,
};

static int slirp_setup(char *str, char **mac_out, void *data)
{
	struct slirp_init *init = data;
	int i=0;

	*init = ((struct slirp_init) { .argw = { { "slirp", NULL  } } });

	str = split_if_spec(str, mac_out, NULL);

	if (str == NULL) /* no command line given after MAC addr */
		return 1;

	do {
		if (i >= SLIRP_MAX_ARGS - 1) {
			printk(KERN_WARNING "slirp_setup: truncating slirp "
			       "arguments\n");
			break;
		}
		init->argw.argv[i++] = str;
		while(*str && *str!=',') {
			if (*str == '_')
				*str=' ';
			str++;
		}
		if (*str != ',')
			break;
		*str++ = '\0';
	} while (1);

	init->argw.argv[i] = NULL;
	return 1;
}

static struct transport slirp_transport = {
	.list 		= LIST_HEAD_INIT(slirp_transport.list),
	.name 		= "slirp",
	.setup  	= slirp_setup,
	.user 		= &slirp_user_info,
	.kern 		= &slirp_kern_info,
	.private_size 	= sizeof(struct slirp_data),
	.setup_size 	= sizeof(struct slirp_init),
};

static int register_slirp(void)
{
	register_transport(&slirp_transport);
	return 0;
}

late_initcall(register_slirp);