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WSL2-Linux-Kernel
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WSL2-Linux-Kernel/drivers/net/vrf.c

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C
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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* 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
*/
#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/route.h>
#include <net/addrconf.h>
#include <net/l3mdev.h>
#include <net/fib_rules.h>
#include <net/netns/generic.h>
#define DRV_NAME "vrf"
#define DRV_VERSION "1.0"
#define FIB_RULE_PREF 1000 /* default preference for FIB rules */
static unsigned int vrf_net_id;
struct net_vrf {
struct rtable __rcu *rth;
struct rt6_info __rcu *rt6;
#if IS_ENABLED(CONFIG_IPV6)
struct fib6_table *fib6_table;
#endif
u32 tb_id;
};
struct pcpu_dstats {
u64 tx_pkts;
u64 tx_bytes;
u64 tx_drps;
u64 rx_pkts;
u64 rx_bytes;
u64 rx_drps;
struct u64_stats_sync syncp;
};
static void vrf_rx_stats(struct net_device *dev, int len)
{
struct pcpu_dstats *dstats = this_cpu_ptr(dev->dstats);
u64_stats_update_begin(&dstats->syncp);
dstats->rx_pkts++;
dstats->rx_bytes += len;
u64_stats_update_end(&dstats->syncp);
}
static void vrf_tx_error(struct net_device *vrf_dev, struct sk_buff *skb)
{
vrf_dev->stats.tx_errors++;
kfree_skb(skb);
}
static void 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(&dstats->syncp, start));
stats->tx_bytes += tbytes;
stats->tx_packets += tpkts;
stats->tx_dropped += tdrops;
stats->rx_bytes += rbytes;
stats->rx_packets += rpkts;
}
}
/* by default VRF devices do not have a qdisc and are expected
* to be created with only a single queue.
*/
static bool qdisc_tx_is_default(const struct net_device *dev)
{
struct netdev_queue *txq;
struct Qdisc *qdisc;
if (dev->num_tx_queues > 1)
return false;
txq = netdev_get_tx_queue(dev, 0);
qdisc = rcu_access_pointer(txq->qdisc);
return !qdisc->enqueue;
}
/* Local traffic destined to local address. Reinsert the packet to rx
* path, similar to loopback handling.
*/
static int vrf_local_xmit(struct sk_buff *skb, struct net_device *dev,
struct dst_entry *dst)
{
int len = skb->len;
skb_orphan(skb);
skb_dst_set(skb, dst);
/* set pkt_type to avoid skb hitting packet taps twice -
* once on Tx and again in Rx processing
*/
skb->pkt_type = PACKET_LOOPBACK;
skb->protocol = eth_type_trans(skb, dev);
if (likely(netif_rx(skb) == NET_RX_SUCCESS))
vrf_rx_stats(dev, len);
else
this_cpu_inc(dev->dstats->rx_drps);
return NETDEV_TX_OK;
}
#if IS_ENABLED(CONFIG_IPV6)
static int vrf_ip6_local_out(struct net *net, struct sock *sk,
struct sk_buff *skb)
{
int err;
err = nf_hook(NFPROTO_IPV6, NF_INET_LOCAL_OUT, net,
sk, skb, NULL, skb_dst(skb)->dev, dst_output);
if (likely(err == 1))
err = dst_output(net, sk, skb);
return err;
}
static netdev_tx_t vrf_process_v6_outbound(struct sk_buff *skb,
struct net_device *dev)
{
const struct ipv6hdr *iph = ipv6_hdr(skb);
struct net *net = dev_net(skb->dev);
struct flowi6 fl6 = {
/* needed to match OIF rule */
.flowi6_oif = dev->ifindex,
.flowi6_iif = LOOPBACK_IFINDEX,
.daddr = iph->daddr,
.saddr = iph->saddr,
.flowlabel = ip6_flowinfo(iph),
.flowi6_mark = skb->mark,
.flowi6_proto = iph->nexthdr,
.flowi6_flags = FLOWI_FLAG_SKIP_NH_OIF,
};
int ret = NET_XMIT_DROP;
struct dst_entry *dst;
struct dst_entry *dst_null = &net->ipv6.ip6_null_entry->dst;
dst = ip6_route_output(net, NULL, &fl6);
if (dst == dst_null)
goto err;
skb_dst_drop(skb);
/* if dst.dev is loopback or the VRF device again this is locally
* originated traffic destined to a local address. Short circuit
* to Rx path
*/
if (dst->dev == dev)
return vrf_local_xmit(skb, dev, dst);
skb_dst_set(skb, dst);
/* strip the ethernet header added for pass through VRF device */
__skb_pull(skb, skb_network_offset(skb));
ret = vrf_ip6_local_out(net, skb->sk, skb);
if (unlikely(net_xmit_eval(ret)))
dev->stats.tx_errors++;
else
ret = NET_XMIT_SUCCESS;
return ret;
err:
vrf_tx_error(dev, skb);
return NET_XMIT_DROP;
}
#else
static netdev_tx_t vrf_process_v6_outbound(struct sk_buff *skb,
struct net_device *dev)
{
vrf_tx_error(dev, skb);
return NET_XMIT_DROP;
}
#endif
/* based on ip_local_out; can't use it b/c the dst is switched pointing to us */
static int vrf_ip_local_out(struct net *net, struct sock *sk,
struct sk_buff *skb)
{
int err;
err = nf_hook(NFPROTO_IPV4, NF_INET_LOCAL_OUT, net, sk,
skb, NULL, skb_dst(skb)->dev, dst_output);
if (likely(err == 1))
err = dst_output(net, sk, skb);
return err;
}
static netdev_tx_t vrf_process_v4_outbound(struct sk_buff *skb,
struct net_device *vrf_dev)
{
struct iphdr *ip4h = ip_hdr(skb);
int ret = NET_XMIT_DROP;
struct flowi4 fl4 = {
/* needed to match OIF rule */
.flowi4_oif = vrf_dev->ifindex,
.flowi4_iif = LOOPBACK_IFINDEX,
.flowi4_tos = RT_TOS(ip4h->tos),
.flowi4_flags = FLOWI_FLAG_ANYSRC | FLOWI_FLAG_SKIP_NH_OIF,
.flowi4_proto = ip4h->protocol,
.daddr = ip4h->daddr,
.saddr = ip4h->saddr,
};
struct net *net = dev_net(vrf_dev);
struct rtable *rt;
rt = ip_route_output_flow(net, &fl4, NULL);
if (IS_ERR(rt))
goto err;
skb_dst_drop(skb);
/* if dst.dev is loopback or the VRF device again this is locally
* originated traffic destined to a local address. Short circuit
* to Rx path
*/
if (rt->dst.dev == vrf_dev)
return vrf_local_xmit(skb, vrf_dev, &rt->dst);
skb_dst_set(skb, &rt->dst);
/* strip the ethernet header added for pass through VRF device */
__skb_pull(skb, skb_network_offset(skb));
if (!ip4h->saddr) {
ip4h->saddr = inet_select_addr(skb_dst(skb)->dev, 0,
RT_SCOPE_LINK);
}
ret = vrf_ip_local_out(dev_net(skb_dst(skb)->dev), skb->sk, skb);
if (unlikely(net_xmit_eval(ret)))
vrf_dev->stats.tx_errors++;
else
ret = NET_XMIT_SUCCESS;
out:
return ret;
err:
vrf_tx_error(vrf_dev, skb);
goto out;
}
static netdev_tx_t is_ip_tx_frame(struct sk_buff *skb, struct net_device *dev)
{
switch (skb->protocol) {
case htons(ETH_P_IP):
return vrf_process_v4_outbound(skb, dev);
case htons(ETH_P_IPV6):
return vrf_process_v6_outbound(skb, dev);
default:
vrf_tx_error(dev, skb);
return NET_XMIT_DROP;
}
}
static netdev_tx_t vrf_xmit(struct sk_buff *skb, struct net_device *dev)
{
int len = skb->len;
netdev_tx_t ret = is_ip_tx_frame(skb, dev);
if (likely(ret == NET_XMIT_SUCCESS || ret == NET_XMIT_CN)) {
struct pcpu_dstats *dstats = this_cpu_ptr(dev->dstats);
u64_stats_update_begin(&dstats->syncp);
dstats->tx_pkts++;
dstats->tx_bytes += len;
u64_stats_update_end(&dstats->syncp);
} else {
this_cpu_inc(dev->dstats->tx_drps);
}
return ret;
}
static int vrf_finish_direct(struct net *net, struct sock *sk,
struct sk_buff *skb)
{
struct net_device *vrf_dev = skb->dev;
if (!list_empty(&vrf_dev->ptype_all) &&
likely(skb_headroom(skb) >= ETH_HLEN)) {
struct ethhdr *eth = skb_push(skb, ETH_HLEN);
ether_addr_copy(eth->h_source, vrf_dev->dev_addr);
eth_zero_addr(eth->h_dest);
eth->h_proto = skb->protocol;
rcu_read_lock_bh();
dev_queue_xmit_nit(skb, vrf_dev);
rcu_read_unlock_bh();
skb_pull(skb, ETH_HLEN);
}
return 1;
}
#if IS_ENABLED(CONFIG_IPV6)
/* modelled after ip6_finish_output2 */
static int vrf_finish_output6(struct net *net, struct sock *sk,
struct sk_buff *skb)
{
struct dst_entry *dst = skb_dst(skb);
struct net_device *dev = dst->dev;
struct neighbour *neigh;
struct in6_addr *nexthop;
int ret;
nf_reset(skb);
skb->protocol = htons(ETH_P_IPV6);
skb->dev = dev;
rcu_read_lock_bh();
nexthop = rt6_nexthop((struct rt6_info *)dst, &ipv6_hdr(skb)->daddr);
neigh = __ipv6_neigh_lookup_noref(dst->dev, nexthop);
if (unlikely(!neigh))
neigh = __neigh_create(&nd_tbl, nexthop, dst->dev, false);
if (!IS_ERR(neigh)) {
sock_confirm_neigh(skb, neigh);
ret = neigh_output(neigh, skb, false);
rcu_read_unlock_bh();
return ret;
}
rcu_read_unlock_bh();
IP6_INC_STATS(dev_net(dst->dev),
ip6_dst_idev(dst), IPSTATS_MIB_OUTNOROUTES);
kfree_skb(skb);
return -EINVAL;
}
/* modelled after ip6_output */
static int vrf_output6(struct net *net, struct sock *sk, struct sk_buff *skb)
{
return NF_HOOK_COND(NFPROTO_IPV6, NF_INET_POST_ROUTING,
net, sk, skb, NULL, skb_dst(skb)->dev,
vrf_finish_output6,
!(IP6CB(skb)->flags & IP6SKB_REROUTED));
}
/* set dst on skb to send packet to us via dev_xmit path. Allows
* packet to go through device based features such as qdisc, netfilter
* hooks and packet sockets with skb->dev set to vrf device.
*/
static struct sk_buff *vrf_ip6_out_redirect(struct net_device *vrf_dev,
struct sk_buff *skb)
{
struct net_vrf *vrf = netdev_priv(vrf_dev);
struct dst_entry *dst = NULL;
struct rt6_info *rt6;
rcu_read_lock();
rt6 = rcu_dereference(vrf->rt6);
if (likely(rt6)) {
dst = &rt6->dst;
dst_hold(dst);
}
rcu_read_unlock();
if (unlikely(!dst)) {
vrf_tx_error(vrf_dev, skb);
return NULL;
}
skb_dst_drop(skb);
skb_dst_set(skb, dst);
return skb;
}
static int vrf_output6_direct(struct net *net, struct sock *sk,
struct sk_buff *skb)
{
skb->protocol = htons(ETH_P_IPV6);
return NF_HOOK_COND(NFPROTO_IPV6, NF_INET_POST_ROUTING,
net, sk, skb, NULL, skb->dev,
vrf_finish_direct,
!(IPCB(skb)->flags & IPSKB_REROUTED));
}
static struct sk_buff *vrf_ip6_out_direct(struct net_device *vrf_dev,
struct sock *sk,
struct sk_buff *skb)
{
struct net *net = dev_net(vrf_dev);
int err;
skb->dev = vrf_dev;
err = nf_hook(NFPROTO_IPV6, NF_INET_LOCAL_OUT, net, sk,
skb, NULL, vrf_dev, vrf_output6_direct);
if (likely(err == 1))
err = vrf_output6_direct(net, sk, skb);
/* reset skb device */
if (likely(err == 1))
nf_reset(skb);
else
skb = NULL;
return skb;
}
static struct sk_buff *vrf_ip6_out(struct net_device *vrf_dev,
struct sock *sk,
struct sk_buff *skb)
{
/* don't divert link scope packets */
if (rt6_need_strict(&ipv6_hdr(skb)->daddr))
return skb;
if (qdisc_tx_is_default(vrf_dev))
return vrf_ip6_out_direct(vrf_dev, sk, skb);
return vrf_ip6_out_redirect(vrf_dev, skb);
}
/* holding rtnl */
static void vrf_rt6_release(struct net_device *dev, struct net_vrf *vrf)
{
struct rt6_info *rt6 = rtnl_dereference(vrf->rt6);
struct net *net = dev_net(dev);
struct dst_entry *dst;
RCU_INIT_POINTER(vrf->rt6, NULL);
synchronize_rcu();
/* move dev in dst's to loopback so this VRF device can be deleted
* - based on dst_ifdown
*/
if (rt6) {
dst = &rt6->dst;
dev_put(dst->dev);
dst->dev = net->loopback_dev;
dev_hold(dst->dev);
dst_release(dst);
}
}
static int vrf_rt6_create(struct net_device *dev)
{
int flags = DST_HOST | DST_NOPOLICY | DST_NOXFRM;
struct net_vrf *vrf = netdev_priv(dev);
struct net *net = dev_net(dev);
struct rt6_info *rt6;
int rc = -ENOMEM;
/* IPv6 can be CONFIG enabled and then disabled runtime */
if (!ipv6_mod_enabled())
return 0;
vrf->fib6_table = fib6_new_table(net, vrf->tb_id);
if (!vrf->fib6_table)
goto out;
/* create a dst for routing packets out a VRF device */
rt6 = ip6_dst_alloc(net, dev, flags);
if (!rt6)
goto out;
rt6->dst.output = vrf_output6;
rcu_assign_pointer(vrf->rt6, rt6);
rc = 0;
out:
return rc;
}
#else
static struct sk_buff *vrf_ip6_out(struct net_device *vrf_dev,
struct sock *sk,
struct sk_buff *skb)
{
return skb;
}
static void vrf_rt6_release(struct net_device *dev, struct net_vrf *vrf)
{
}
static int vrf_rt6_create(struct net_device *dev)
{
return 0;
}
#endif
/* modelled after ip_finish_output2 */
static int vrf_finish_output(struct net *net, struct sock *sk, struct sk_buff *skb)
{
struct dst_entry *dst = skb_dst(skb);
struct rtable *rt = (struct rtable *)dst;
struct net_device *dev = dst->dev;
unsigned int hh_len = LL_RESERVED_SPACE(dev);
struct neighbour *neigh;
bool is_v6gw = false;
int ret = -EINVAL;
nf_reset(skb);
/* Be paranoid, rather than too clever. */
if (unlikely(skb_headroom(skb) < hh_len && dev->header_ops)) {
struct sk_buff *skb2;
skb2 = skb_realloc_headroom(skb, LL_RESERVED_SPACE(dev));
if (!skb2) {
ret = -ENOMEM;
goto err;
}
if (skb->sk)
skb_set_owner_w(skb2, skb->sk);
consume_skb(skb);
skb = skb2;
}
rcu_read_lock_bh();
neigh = ip_neigh_for_gw(rt, skb, &is_v6gw);
if (!IS_ERR(neigh)) {
sock_confirm_neigh(skb, neigh);
/* if crossing protocols, can not use the cached header */
ret = neigh_output(neigh, skb, is_v6gw);
rcu_read_unlock_bh();
return ret;
}
rcu_read_unlock_bh();
err:
vrf_tx_error(skb->dev, skb);
return ret;
}
static int vrf_output(struct net *net, struct sock *sk, struct sk_buff *skb)
{
struct net_device *dev = skb_dst(skb)->dev;
IP_UPD_PO_STATS(net, IPSTATS_MIB_OUT, skb->len);
skb->dev = dev;
skb->protocol = htons(ETH_P_IP);
return NF_HOOK_COND(NFPROTO_IPV4, NF_INET_POST_ROUTING,
net, sk, skb, NULL, dev,
vrf_finish_output,
!(IPCB(skb)->flags & IPSKB_REROUTED));
}
/* set dst on skb to send packet to us via dev_xmit path. Allows
* packet to go through device based features such as qdisc, netfilter
* hooks and packet sockets with skb->dev set to vrf device.
*/
static struct sk_buff *vrf_ip_out_redirect(struct net_device *vrf_dev,
struct sk_buff *skb)
{
struct net_vrf *vrf = netdev_priv(vrf_dev);
struct dst_entry *dst = NULL;
struct rtable *rth;
rcu_read_lock();
rth = rcu_dereference(vrf->rth);
if (likely(rth)) {
dst = &rth->dst;
dst_hold(dst);
}
rcu_read_unlock();
if (unlikely(!dst)) {
vrf_tx_error(vrf_dev, skb);
return NULL;
}
skb_dst_drop(skb);
skb_dst_set(skb, dst);
return skb;
}
static int vrf_output_direct(struct net *net, struct sock *sk,
struct sk_buff *skb)
{
skb->protocol = htons(ETH_P_IP);
return NF_HOOK_COND(NFPROTO_IPV4, NF_INET_POST_ROUTING,
net, sk, skb, NULL, skb->dev,
vrf_finish_direct,
!(IPCB(skb)->flags & IPSKB_REROUTED));
}
static struct sk_buff *vrf_ip_out_direct(struct net_device *vrf_dev,
struct sock *sk,
struct sk_buff *skb)
{
struct net *net = dev_net(vrf_dev);
int err;
skb->dev = vrf_dev;
err = nf_hook(NFPROTO_IPV4, NF_INET_LOCAL_OUT, net, sk,
skb, NULL, vrf_dev, vrf_output_direct);
if (likely(err == 1))
err = vrf_output_direct(net, sk, skb);
/* reset skb device */
if (likely(err == 1))
nf_reset(skb);
else
skb = NULL;
return skb;
}
static struct sk_buff *vrf_ip_out(struct net_device *vrf_dev,
struct sock *sk,
struct sk_buff *skb)
{
/* don't divert multicast or local broadcast */
if (ipv4_is_multicast(ip_hdr(skb)->daddr) ||
ipv4_is_lbcast(ip_hdr(skb)->daddr))
return skb;
if (qdisc_tx_is_default(vrf_dev))
return vrf_ip_out_direct(vrf_dev, sk, skb);
return vrf_ip_out_redirect(vrf_dev, skb);
}
/* called with rcu lock held */
static struct sk_buff *vrf_l3_out(struct net_device *vrf_dev,
struct sock *sk,
struct sk_buff *skb,
u16 proto)
{
switch (proto) {
case AF_INET:
return vrf_ip_out(vrf_dev, sk, skb);
case AF_INET6:
return vrf_ip6_out(vrf_dev, sk, skb);
}
return skb;
}
/* holding rtnl */
static void vrf_rtable_release(struct net_device *dev, struct net_vrf *vrf)
{
struct rtable *rth = rtnl_dereference(vrf->rth);
struct net *net = dev_net(dev);
struct dst_entry *dst;
RCU_INIT_POINTER(vrf->rth, NULL);
synchronize_rcu();
/* move dev in dst's to loopback so this VRF device can be deleted
* - based on dst_ifdown
*/
if (rth) {
dst = &rth->dst;
dev_put(dst->dev);
dst->dev = net->loopback_dev;
dev_hold(dst->dev);
dst_release(dst);
}
}
static int vrf_rtable_create(struct net_device *dev)
{
struct net_vrf *vrf = netdev_priv(dev);
struct rtable *rth;
if (!fib_new_table(dev_net(dev), vrf->tb_id))
return -ENOMEM;
/* create a dst for routing packets out through a VRF device */
rth = rt_dst_alloc(dev, 0, RTN_UNICAST, 1, 1, 0);
if (!rth)
return -ENOMEM;
rth->dst.output = vrf_output;
rcu_assign_pointer(vrf->rth, rth);
return 0;
}
/**************************** device handling ********************/
/* cycle interface to flush neighbor cache and move routes across tables */
static void cycle_netdev(struct net_device *dev,
struct netlink_ext_ack *extack)
{
unsigned int flags = dev->flags;
int ret;
if (!netif_running(dev))
return;
ret = dev_change_flags(dev, flags & ~IFF_UP, extack);
if (ret >= 0)
ret = dev_change_flags(dev, flags, extack);
if (ret < 0) {
netdev_err(dev,
"Failed to cycle device %s; route tables might be wrong!\n",
dev->name);
}
}
static int do_vrf_add_slave(struct net_device *dev, struct net_device *port_dev,
struct netlink_ext_ack *extack)
{
int ret;
/* do not allow loopback device to be enslaved to a VRF.
* The vrf device acts as the loopback for the vrf.
*/
if (port_dev == dev_net(dev)->loopback_dev) {
NL_SET_ERR_MSG(extack,
"Can not enslave loopback device to a VRF");
return -EOPNOTSUPP;
}
port_dev->priv_flags |= IFF_L3MDEV_SLAVE;
ret = netdev_master_upper_dev_link(port_dev, dev, NULL, NULL, extack);
if (ret < 0)
goto err;
cycle_netdev(port_dev, extack);
return 0;
err:
port_dev->priv_flags &= ~IFF_L3MDEV_SLAVE;
return ret;
}
static int vrf_add_slave(struct net_device *dev, struct net_device *port_dev,
struct netlink_ext_ack *extack)
{
if (netif_is_l3_master(port_dev)) {
NL_SET_ERR_MSG(extack,
"Can not enslave an L3 master device to a VRF");
return -EINVAL;
}
if (netif_is_l3_slave(port_dev))
return -EINVAL;
return do_vrf_add_slave(dev, port_dev, extack);
}
/* inverse of do_vrf_add_slave */
static int do_vrf_del_slave(struct net_device *dev, struct net_device *port_dev)
{
netdev_upper_dev_unlink(port_dev, dev);
port_dev->priv_flags &= ~IFF_L3MDEV_SLAVE;
cycle_netdev(port_dev, NULL);
return 0;
}
static int vrf_del_slave(struct net_device *dev, struct net_device *port_dev)
{
return do_vrf_del_slave(dev, port_dev);
}
static void vrf_dev_uninit(struct net_device *dev)
{
struct net_vrf *vrf = netdev_priv(dev);
vrf_rtable_release(dev, vrf);
vrf_rt6_release(dev, vrf);
free_percpu(dev->dstats);
dev->dstats = NULL;
}
static int vrf_dev_init(struct net_device *dev)
{
struct net_vrf *vrf = netdev_priv(dev);
dev->dstats = netdev_alloc_pcpu_stats(struct pcpu_dstats);
if (!dev->dstats)
goto out_nomem;
/* create the default dst which points back to us */
if (vrf_rtable_create(dev) != 0)
goto out_stats;
if (vrf_rt6_create(dev) != 0)
goto out_rth;
dev->flags = IFF_MASTER | IFF_NOARP;
/* MTU is irrelevant for VRF device; set to 64k similar to lo */
dev->mtu = 64 * 1024;
/* similarly, oper state is irrelevant; set to up to avoid confusion */
dev->operstate = IF_OPER_UP;
netdev_lockdep_set_classes(dev);
return 0;
out_rth:
vrf_rtable_release(dev, vrf);
out_stats:
free_percpu(dev->dstats);
dev->dstats = NULL;
out_nomem:
return -ENOMEM;
}
static const struct net_device_ops vrf_netdev_ops = {
.ndo_init = vrf_dev_init,
.ndo_uninit = vrf_dev_uninit,
.ndo_start_xmit = vrf_xmit,
.ndo_set_mac_address = eth_mac_addr,
.ndo_get_stats64 = vrf_get_stats64,
.ndo_add_slave = vrf_add_slave,
.ndo_del_slave = vrf_del_slave,
};
static u32 vrf_fib_table(const struct net_device *dev)
{
struct net_vrf *vrf = netdev_priv(dev);
return vrf->tb_id;
}
static int vrf_rcv_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
{
kfree_skb(skb);
return 0;
}
static struct sk_buff *vrf_rcv_nfhook(u8 pf, unsigned int hook,
struct sk_buff *skb,
struct net_device *dev)
{
struct net *net = dev_net(dev);
if (nf_hook(pf, hook, net, NULL, skb, dev, NULL, vrf_rcv_finish) != 1)
skb = NULL; /* kfree_skb(skb) handled by nf code */
return skb;
}
#if IS_ENABLED(CONFIG_IPV6)
/* 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.
*/
static bool ipv6_ndisc_frame(const struct sk_buff *skb)
{
const struct ipv6hdr *iph = ipv6_hdr(skb);
bool rc = false;
if (iph->nexthdr == NEXTHDR_ICMP) {
const struct icmp6hdr *icmph;
struct icmp6hdr _icmph;
icmph = skb_header_pointer(skb, sizeof(*iph),
sizeof(_icmph), &_icmph);
if (!icmph)
goto out;
switch (icmph->icmp6_type) {
case NDISC_ROUTER_SOLICITATION:
case NDISC_ROUTER_ADVERTISEMENT:
case NDISC_NEIGHBOUR_SOLICITATION:
case NDISC_NEIGHBOUR_ADVERTISEMENT:
case NDISC_REDIRECT:
rc = true;
break;
}
}
out:
return rc;
}
static struct rt6_info *vrf_ip6_route_lookup(struct net *net,
const struct net_device *dev,
struct flowi6 *fl6,
int ifindex,
const struct sk_buff *skb,
int flags)
{
struct net_vrf *vrf = netdev_priv(dev);
return ip6_pol_route(net, vrf->fib6_table, ifindex, fl6, skb, flags);
}
static void vrf_ip6_input_dst(struct sk_buff *skb, struct net_device *vrf_dev,
int ifindex)
{
const struct ipv6hdr *iph = ipv6_hdr(skb);
struct flowi6 fl6 = {
.flowi6_iif = ifindex,
.flowi6_mark = skb->mark,
.flowi6_proto = iph->nexthdr,
.daddr = iph->daddr,
.saddr = iph->saddr,
.flowlabel = ip6_flowinfo(iph),
};
struct net *net = dev_net(vrf_dev);
struct rt6_info *rt6;
rt6 = vrf_ip6_route_lookup(net, vrf_dev, &fl6, ifindex, skb,
RT6_LOOKUP_F_HAS_SADDR | RT6_LOOKUP_F_IFACE);
if (unlikely(!rt6))
return;
if (unlikely(&rt6->dst == &net->ipv6.ip6_null_entry->dst))
return;
skb_dst_set(skb, &rt6->dst);
}
static struct sk_buff *vrf_ip6_rcv(struct net_device *vrf_dev,
struct sk_buff *skb)
{
int orig_iif = skb->skb_iif;
bool need_strict = rt6_need_strict(&ipv6_hdr(skb)->daddr);
bool is_ndisc = ipv6_ndisc_frame(skb);
/* loopback, multicast & non-ND link-local traffic; do not push through
* packet taps again. Reset pkt_type for upper layers to process skb
*/
if (skb->pkt_type == PACKET_LOOPBACK || (need_strict && !is_ndisc)) {
skb->dev = vrf_dev;
skb->skb_iif = vrf_dev->ifindex;
IP6CB(skb)->flags |= IP6SKB_L3SLAVE;
if (skb->pkt_type == PACKET_LOOPBACK)
skb->pkt_type = PACKET_HOST;
goto out;
}
/* if packet is NDISC then keep the ingress interface */
if (!is_ndisc) {
vrf_rx_stats(vrf_dev, skb->len);
skb->dev = vrf_dev;
skb->skb_iif = vrf_dev->ifindex;
if (!list_empty(&vrf_dev->ptype_all)) {
skb_push(skb, skb->mac_len);
dev_queue_xmit_nit(skb, vrf_dev);
skb_pull(skb, skb->mac_len);
}
IP6CB(skb)->flags |= IP6SKB_L3SLAVE;
}
if (need_strict)
vrf_ip6_input_dst(skb, vrf_dev, orig_iif);
skb = vrf_rcv_nfhook(NFPROTO_IPV6, NF_INET_PRE_ROUTING, skb, vrf_dev);
out:
return skb;
}
#else
static struct sk_buff *vrf_ip6_rcv(struct net_device *vrf_dev,
struct sk_buff *skb)
{
return skb;
}
#endif
static struct sk_buff *vrf_ip_rcv(struct net_device *vrf_dev,
struct sk_buff *skb)
{
skb->dev = vrf_dev;
skb->skb_iif = vrf_dev->ifindex;
IPCB(skb)->flags |= IPSKB_L3SLAVE;
if (ipv4_is_multicast(ip_hdr(skb)->daddr))
goto out;
/* loopback traffic; do not push through packet taps again.
* Reset pkt_type for upper layers to process skb
*/
if (skb->pkt_type == PACKET_LOOPBACK) {
skb->pkt_type = PACKET_HOST;
goto out;
}
vrf_rx_stats(vrf_dev, skb->len);
if (!list_empty(&vrf_dev->ptype_all)) {
skb_push(skb, skb->mac_len);
dev_queue_xmit_nit(skb, vrf_dev);
skb_pull(skb, skb->mac_len);
}
skb = vrf_rcv_nfhook(NFPROTO_IPV4, NF_INET_PRE_ROUTING, skb, vrf_dev);
out:
return skb;
}
/* called with rcu lock held */
static struct sk_buff *vrf_l3_rcv(struct net_device *vrf_dev,
struct sk_buff *skb,
u16 proto)
{
switch (proto) {
case AF_INET:
return vrf_ip_rcv(vrf_dev, skb);
case AF_INET6:
return vrf_ip6_rcv(vrf_dev, skb);
}
return skb;
}
#if IS_ENABLED(CONFIG_IPV6)
/* send to link-local or multicast address via interface enslaved to
* VRF device. Force lookup to VRF table without changing flow struct
*/
static struct dst_entry *vrf_link_scope_lookup(const struct net_device *dev,
struct flowi6 *fl6)
{
struct net *net = dev_net(dev);
int flags = RT6_LOOKUP_F_IFACE;
struct dst_entry *dst = NULL;
struct rt6_info *rt;
/* VRF device does not have a link-local address and
* sending packets to link-local or mcast addresses over
* a VRF device does not make sense
*/
if (fl6->flowi6_oif == dev->ifindex) {
dst = &net->ipv6.ip6_null_entry->dst;
dst_hold(dst);
return dst;
}
if (!ipv6_addr_any(&fl6->saddr))
flags |= RT6_LOOKUP_F_HAS_SADDR;
rt = vrf_ip6_route_lookup(net, dev, fl6, fl6->flowi6_oif, NULL, flags);
if (rt)
dst = &rt->dst;
return dst;
}
#endif
static const struct l3mdev_ops vrf_l3mdev_ops = {
.l3mdev_fib_table = vrf_fib_table,
.l3mdev_l3_rcv = vrf_l3_rcv,
.l3mdev_l3_out = vrf_l3_out,
#if IS_ENABLED(CONFIG_IPV6)
.l3mdev_link_scope_lookup = vrf_link_scope_lookup,
#endif
};
static void vrf_get_drvinfo(struct net_device *dev,
struct ethtool_drvinfo *info)
{
strlcpy(info->driver, DRV_NAME, sizeof(info->driver));
strlcpy(info->version, DRV_VERSION, sizeof(info->version));
}
static const struct ethtool_ops vrf_ethtool_ops = {
.get_drvinfo = vrf_get_drvinfo,
};
static inline size_t vrf_fib_rule_nl_size(void)
{
size_t sz;
sz = NLMSG_ALIGN(sizeof(struct fib_rule_hdr));
sz += nla_total_size(sizeof(u8)); /* FRA_L3MDEV */
sz += nla_total_size(sizeof(u32)); /* FRA_PRIORITY */
sz += nla_total_size(sizeof(u8)); /* FRA_PROTOCOL */
return sz;
}
static int vrf_fib_rule(const struct net_device *dev, __u8 family, bool add_it)
{
struct fib_rule_hdr *frh;
struct nlmsghdr *nlh;
struct sk_buff *skb;
int err;
if (family == AF_INET6 && !ipv6_mod_enabled())
return 0;
skb = nlmsg_new(vrf_fib_rule_nl_size(), GFP_KERNEL);
if (!skb)
return -ENOMEM;
nlh = nlmsg_put(skb, 0, 0, 0, sizeof(*frh), 0);
if (!nlh)
goto nla_put_failure;
/* rule only needs to appear once */
nlh->nlmsg_flags |= NLM_F_EXCL;
frh = nlmsg_data(nlh);
memset(frh, 0, sizeof(*frh));
frh->family = family;
frh->action = FR_ACT_TO_TBL;
if (nla_put_u8(skb, FRA_PROTOCOL, RTPROT_KERNEL))
goto nla_put_failure;
if (nla_put_u8(skb, FRA_L3MDEV, 1))
goto nla_put_failure;
if (nla_put_u32(skb, FRA_PRIORITY, FIB_RULE_PREF))
goto nla_put_failure;
nlmsg_end(skb, nlh);
/* fib_nl_{new,del}rule handling looks for net from skb->sk */
skb->sk = dev_net(dev)->rtnl;
if (add_it) {
err = fib_nl_newrule(skb, nlh, NULL);
if (err == -EEXIST)
err = 0;
} else {
err = fib_nl_delrule(skb, nlh, NULL);
if (err == -ENOENT)
err = 0;
}
nlmsg_free(skb);
return err;
nla_put_failure:
nlmsg_free(skb);
return -EMSGSIZE;
}
static int vrf_add_fib_rules(const struct net_device *dev)
{
int err;
err = vrf_fib_rule(dev, AF_INET, true);
if (err < 0)
goto out_err;
err = vrf_fib_rule(dev, AF_INET6, true);
if (err < 0)
goto ipv6_err;
#if IS_ENABLED(CONFIG_IP_MROUTE_MULTIPLE_TABLES)
err = vrf_fib_rule(dev, RTNL_FAMILY_IPMR, true);
if (err < 0)
goto ipmr_err;
#endif
#if IS_ENABLED(CONFIG_IPV6_MROUTE_MULTIPLE_TABLES)
err = vrf_fib_rule(dev, RTNL_FAMILY_IP6MR, true);
if (err < 0)
goto ip6mr_err;
#endif
return 0;
#if IS_ENABLED(CONFIG_IPV6_MROUTE_MULTIPLE_TABLES)
ip6mr_err:
vrf_fib_rule(dev, RTNL_FAMILY_IPMR, false);
#endif
#if IS_ENABLED(CONFIG_IP_MROUTE_MULTIPLE_TABLES)
ipmr_err:
vrf_fib_rule(dev, AF_INET6, false);
#endif
ipv6_err:
vrf_fib_rule(dev, AF_INET, false);
out_err:
netdev_err(dev, "Failed to add FIB rules.\n");
return err;
}
static void vrf_setup(struct net_device *dev)
{
ether_setup(dev);
/* Initialize the device structure. */
dev->netdev_ops = &vrf_netdev_ops;
dev->l3mdev_ops = &vrf_l3mdev_ops;
dev->ethtool_ops = &vrf_ethtool_ops;
dev->needs_free_netdev = true;
/* Fill in device structure with ethernet-generic values. */
eth_hw_addr_random(dev);
/* don't acquire vrf device's netif_tx_lock when transmitting */
dev->features |= NETIF_F_LLTX;
/* don't allow vrf devices to change network namespaces. */
dev->features |= NETIF_F_NETNS_LOCAL;
/* does not make sense for a VLAN to be added to a vrf device */
dev->features |= NETIF_F_VLAN_CHALLENGED;
/* enable offload features */
dev->features |= NETIF_F_GSO_SOFTWARE;
dev->features |= NETIF_F_RXCSUM | NETIF_F_HW_CSUM | NETIF_F_SCTP_CRC;
dev->features |= NETIF_F_SG | NETIF_F_FRAGLIST | NETIF_F_HIGHDMA;
dev->hw_features = dev->features;
dev->hw_enc_features = dev->features;
/* default to no qdisc; user can add if desired */
dev->priv_flags |= IFF_NO_QUEUE;
dev->priv_flags |= IFF_NO_RX_HANDLER;
dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
/* VRF devices do not care about MTU, but if the MTU is set
* too low then the ipv4 and ipv6 protocols are disabled
* which breaks networking.
*/
dev->min_mtu = IPV6_MIN_MTU;
dev->max_mtu = ETH_MAX_MTU;
}
static int vrf_validate(struct nlattr *tb[], struct nlattr *data[],
struct netlink_ext_ack *extack)
{
if (tb[IFLA_ADDRESS]) {
if (nla_len(tb[IFLA_ADDRESS]) != ETH_ALEN) {
NL_SET_ERR_MSG(extack, "Invalid hardware address");
return -EINVAL;
}
if (!is_valid_ether_addr(nla_data(tb[IFLA_ADDRESS]))) {
NL_SET_ERR_MSG(extack, "Invalid hardware address");
return -EADDRNOTAVAIL;
}
}
return 0;
}
static void vrf_dellink(struct net_device *dev, struct list_head *head)
{
struct net_device *port_dev;
struct list_head *iter;
netdev_for_each_lower_dev(dev, port_dev, iter)
vrf_del_slave(dev, port_dev);
unregister_netdevice_queue(dev, head);
}
static int vrf_newlink(struct net *src_net, struct net_device *dev,
struct nlattr *tb[], struct nlattr *data[],
struct netlink_ext_ack *extack)
{
struct net_vrf *vrf = netdev_priv(dev);
bool *add_fib_rules;
struct net *net;
int err;
if (!data || !data[IFLA_VRF_TABLE]) {
NL_SET_ERR_MSG(extack, "VRF table id is missing");
return -EINVAL;
}
vrf->tb_id = nla_get_u32(data[IFLA_VRF_TABLE]);
if (vrf->tb_id == RT_TABLE_UNSPEC) {
NL_SET_ERR_MSG_ATTR(extack, data[IFLA_VRF_TABLE],
"Invalid VRF table id");
return -EINVAL;
}
dev->priv_flags |= IFF_L3MDEV_MASTER;
err = register_netdevice(dev);
if (err)
goto out;
net = dev_net(dev);
add_fib_rules = net_generic(net, vrf_net_id);
if (*add_fib_rules) {
err = vrf_add_fib_rules(dev);
if (err) {
unregister_netdevice(dev);
goto out;
}
*add_fib_rules = false;
}
out:
return err;
}
static size_t vrf_nl_getsize(const struct net_device *dev)
{
return nla_total_size(sizeof(u32)); /* IFLA_VRF_TABLE */
}
static int vrf_fillinfo(struct sk_buff *skb,
const struct net_device *dev)
{
struct net_vrf *vrf = netdev_priv(dev);
return nla_put_u32(skb, IFLA_VRF_TABLE, vrf->tb_id);
}
static size_t vrf_get_slave_size(const struct net_device *bond_dev,
const struct net_device *slave_dev)
{
return nla_total_size(sizeof(u32)); /* IFLA_VRF_PORT_TABLE */
}
static int vrf_fill_slave_info(struct sk_buff *skb,
const struct net_device *vrf_dev,
const struct net_device *slave_dev)
{
struct net_vrf *vrf = netdev_priv(vrf_dev);
if (nla_put_u32(skb, IFLA_VRF_PORT_TABLE, vrf->tb_id))
return -EMSGSIZE;
return 0;
}
static const struct nla_policy vrf_nl_policy[IFLA_VRF_MAX + 1] = {
[IFLA_VRF_TABLE] = { .type = NLA_U32 },
};
static struct rtnl_link_ops vrf_link_ops __read_mostly = {
.kind = DRV_NAME,
.priv_size = sizeof(struct net_vrf),
.get_size = vrf_nl_getsize,
.policy = vrf_nl_policy,
.validate = vrf_validate,
.fill_info = vrf_fillinfo,
.get_slave_size = vrf_get_slave_size,
.fill_slave_info = vrf_fill_slave_info,
.newlink = vrf_newlink,
.dellink = vrf_dellink,
.setup = vrf_setup,
.maxtype = IFLA_VRF_MAX,
};
static int vrf_device_event(struct notifier_block *unused,
unsigned long event, void *ptr)
{
struct net_device *dev = netdev_notifier_info_to_dev(ptr);
/* only care about unregister events to drop slave references */
if (event == NETDEV_UNREGISTER) {
struct net_device *vrf_dev;
if (!netif_is_l3_slave(dev))
goto out;
vrf_dev = netdev_master_upper_dev_get(dev);
vrf_del_slave(vrf_dev, dev);
}
out:
return NOTIFY_DONE;
}
static struct notifier_block vrf_notifier_block __read_mostly = {
.notifier_call = vrf_device_event,
};
/* Initialize per network namespace state */
static int __net_init vrf_netns_init(struct net *net)
{
bool *add_fib_rules = net_generic(net, vrf_net_id);
*add_fib_rules = true;
return 0;
}
static struct pernet_operations vrf_net_ops __net_initdata = {
.init = vrf_netns_init,
.id = &vrf_net_id,
.size = sizeof(bool),
};
static int __init vrf_init_module(void)
{
int rc;
register_netdevice_notifier(&vrf_notifier_block);
rc = register_pernet_subsys(&vrf_net_ops);
if (rc < 0)
goto error;
rc = rtnl_link_register(&vrf_link_ops);
if (rc < 0) {
unregister_pernet_subsys(&vrf_net_ops);
goto error;
}
return 0;
error:
unregister_netdevice_notifier(&vrf_notifier_block);
return rc;
}
module_init(vrf_init_module);
MODULE_AUTHOR("Shrijeet Mukherjee, David Ahern");
MODULE_DESCRIPTION("Device driver to instantiate VRF domains");
MODULE_LICENSE("GPL");
MODULE_ALIAS_RTNL_LINK(DRV_NAME);
MODULE_VERSION(DRV_VERSION);
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