path: root/drivers/net/vrf.c

/*
 * vrf.c: device driver to encapsulate a VRF space
 *
 * Copyright (c) 2015 Cumulus Networks. All rights reserved.
 * Copyright (c) 2015 Shrijeet Mukherjee <shm@cumulusnetworks.com>
 * Copyright (c) 2015 David Ahern <dsa@cumulusnetworks.com>
 *
 * Based on dummy, team and ipvlan drivers
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/ip.h>
#include <linux/init.h>
#include <linux/moduleparam.h>
#include <linux/netfilter.h>
#include <linux/rtnetlink.h>
#include <net/rtnetlink.h>
#include <linux/u64_stats_sync.h>
#include <linux/hashtable.h>

#include <linux/inetdevice.h>
#include <net/arp.h>
#include <net/ip.h>
#include <net/ip_fib.h>
#include <net/ip6_fib.h>
#include <net/ip6_route.h>
#include <net/rtnetlink.h>
#include <net/route.h>
#include <net/addrconf.h>
#include <net/l3mdev.h>

#define RT_FL_TOS(oldflp4) \
	((oldflp4)->flowi4_tos & (IPTOS_RT_MASK | RTO_ONLINK))

#define DRV_NAME	"vrf"
#define DRV_VERSION	"1.0"

#define vrf_master_get_rcu(dev) \
	((struct net_device *)rcu_dereference(dev->rx_handler_data))

struct slave {
	struct list_head        list;
	struct net_device       *dev;
};

struct slave_queue {
	struct list_head        all_slaves;
};

struct net_vrf {
	struct slave_queue      queue;
	struct rtable           *rth;
	struct rt6_info		*rt6;
	u32                     tb_id;
};

struct pcpu_dstats {
	u64			tx_pkts;
	u64			tx_bytes;
	u64			tx_drps;
	u64			rx_pkts;
	u64			rx_bytes;
	struct u64_stats_sync	syncp;
};

static struct dst_entry *vrf_ip_check(struct dst_entry *dst, u32 cookie)
{
	return dst;
}

static int vrf_ip_local_out(struct net *net, struct sock *sk, struct sk_buff *skb)
{
	return ip_local_out(net, sk, skb);
}

static unsigned int vrf_v4_mtu(const struct dst_entry *dst)
{
	/* TO-DO: return max ethernet size? */
	return dst->dev->mtu;
}

static void vrf_dst_destroy(struct dst_entry *dst)
{
	/* our dst lives forever - or until the device is closed */
}

static unsigned int vrf_default_advmss(const struct dst_entry *dst)
{
	return 65535 - 40;
}

static struct dst_ops vrf_dst_ops = {
	.family		= AF_INET,
	.local_out	= vrf_ip_local_out,
	.check		= vrf_ip_check,
	.mtu		= vrf_v4_mtu,
	.destroy	= vrf_dst_destroy,
	.default_advmss	= vrf_default_advmss,
};

/* neighbor handling is done with actual device; do not want
 * to flip skb->dev for those ndisc packets. This really fails
 * for multiple next protocols (e.g., NEXTHDR_HOP). But it is
 * a start.
 */
#if IS_ENABLED(CONFIG_IPV6)
static bool check_ipv6_frame(const struct sk_buff *skb)
{
	const struct ipv6hdr *ipv6h = (struct ipv6hdr *)skb->data;
	size_t hlen = sizeof(*ipv6h);
	bool rc = true;

	if (skb->len < hlen)
		goto out;

	if (ipv6h->nexthdr == NEXTHDR_ICMP) {
		const struct icmp6hdr *icmph;

		if (skb->len < hlen + sizeof(*icmph))
			goto out;

		icmph = (struct icmp6hdr *)(skb->data + sizeof(*ipv6h));
		switch (icmph->icmp6_type) {
		case NDISC_ROUTER_SOLICITATION:
		case NDISC_ROUTER_ADVERTISEMENT:
		case NDISC_NEIGHBOUR_SOLICITATION:
		case NDISC_NEIGHBOUR_ADVERTISEMENT:
		case NDISC_REDIRECT:
			rc = false;
			break;
		}
	}

out:
	return rc;
}
#else
static bool check_ipv6_frame(const struct sk_buff *skb)
{
	return false;
}
#endif

static bool is_ip_rx_frame(struct sk_buff *skb)
{
	switch (skb->protocol) {
	case htons(ETH_P_IP):
		return true;
	case htons(ETH_P_IPV6):
		return check_ipv6_frame(skb);
	}
	return false;
}

static void vrf_tx_error(struct net_device *vrf_dev, struct sk_buff *skb)
{
	vrf_dev->stats.tx_errors++;
	kfree_skb(skb);
}

/* note: already called with rcu_read_lock */
static rx_handler_result_t vrf_handle_frame(struct sk_buff **pskb)
{
	struct sk_buff *skb = *pskb;

	if (is_ip_rx_frame(skb)) {
		struct net_device *dev = vrf_master_get_rcu(skb->dev);
		struct pcpu_dstats *dstats = this_cpu_ptr(dev->dstats);

		u64_stats_update_begin(&dstats->syncp);
		dstats->rx_pkts++;
		dstats->rx_bytes += skb->len;
		u64_stats_update_end(&dstats->syncp);

		skb->dev = dev;

		return RX_HANDLER_ANOTHER;
	}
	return RX_HANDLER_PASS;
}

static struct rtnl_link_stats64 *vrf_get_stats64(struct net_device *dev,
						 struct rtnl_link_stats64 *stats)
{
	int i;

	for_each_possible_cpu(i) {
		const struct pcpu_dstats *dstats;
		u64 tbytes, tpkts, tdrops, rbytes, rpkts;
		unsigned int start;

		dstats = per_cpu_ptr(dev->dstats, i);
		do {
			start = u64_stats_fetch_begin_irq(&dstats->syncp);
			tbytes = dstats->tx_bytes;
			tpkts = dstats->tx_pkts;
			tdrops = dstats->tx_drps;
			rbytes = dstats->rx_bytes;
			rpkts = dstats->rx_pkts;
		} while (u64_stats_fetch_retry_irq(&a