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linux/drivers/net/vrf.c
Lahav Schlesinger 09e856d54b vrf: Reset skb conntrack connection on VRF rcv 
To fix the "reverse-NAT" for replies.

When a packet is sent over a VRF, the POST_ROUTING hooks are called
twice: Once from the VRF interface, and once from the "actual"
interface the packet will be sent from:
1) First SNAT: l3mdev_l3_out() -> vrf_l3_out() -> .. -> vrf_output_direct()
     This causes the POST_ROUTING hooks to run.
2) Second SNAT: 'ip_output()' calls POST_ROUTING hooks again.

Similarly for replies, first ip_rcv() calls PRE_ROUTING hooks, and
second vrf_l3_rcv() calls them again.

As an example, consider the following SNAT rule:
> iptables -t nat -A POSTROUTING -p udp -m udp --dport 53 -j SNAT --to-source 2.2.2.2 -o vrf_1

In this case sending over a VRF will create 2 conntrack entries.
The first is from the VRF interface, which performs the IP SNAT.
The second will run the SNAT, but since the "expected reply" will remain
the same, conntrack randomizes the source port of the packet:
e..g With a socket bound to 1.1.1.1:10000, sending to 3.3.3.3:53, the conntrack
rules are:
udp      17 29 src=2.2.2.2 dst=3.3.3.3 sport=10000 dport=53 packets=1 bytes=68 [UNREPLIED] src=3.3.3.3 dst=2.2.2.2 sport=53 dport=61033 packets=0 bytes=0 mark=0 use=1
udp      17 29 src=1.1.1.1 dst=3.3.3.3 sport=10000 dport=53 packets=1 bytes=68 [UNREPLIED] src=3.3.3.3 dst=2.2.2.2 sport=53 dport=10000 packets=0 bytes=0 mark=0 use=1

i.e. First SNAT IP from 1.1.1.1 --> 2.2.2.2, and second the src port is
SNAT-ed from 10000 --> 61033.

But when a reply is sent (3.3.3.3:53 -> 2.2.2.2:61033) only the later
conntrack entry is matched:
udp      17 29 src=2.2.2.2 dst=3.3.3.3 sport=10000 dport=53 packets=1 bytes=68 src=3.3.3.3 dst=2.2.2.2 sport=53 dport=61033 packets=1 bytes=49 mark=0 use=1
udp      17 28 src=1.1.1.1 dst=3.3.3.3 sport=10000 dport=53 packets=1 bytes=68 [UNREPLIED] src=3.3.3.3 dst=2.2.2.2 sport=53 dport=10000 packets=0 bytes=0 mark=0 use=1

And a "port 61033 unreachable" ICMP packet is sent back.

The issue is that when PRE_ROUTING hooks are called from vrf_l3_rcv(),
the skb already has a conntrack flow attached to it, which means
nf_conntrack_in() will not resolve the flow again.

This means only the dest port is "reverse-NATed" (61033 -> 10000) but
the dest IP remains 2.2.2.2, and since the socket is bound to 1.1.1.1 it's
not received.
This can be verified by logging the 4-tuple of the packet in '__udp4_lib_rcv()'.

The fix is then to reset the flow when skb is received on a VRF, to let
conntrack resolve the flow again (which now will hit the earlier flow).

To reproduce: (Without the fix "Got pkt_to_nat_port" will not be printed by
  running 'bash ./repro'):
  $ cat run_in_A1.py
  import logging
  logging.getLogger("scapy.runtime").setLevel(logging.ERROR)
  from scapy.all import *
  import argparse

  def get_packet_to_send(udp_dst_port, msg_name):
      return Ether(src='11:22:33:44:55:66', dst=iface_mac)/ \
          IP(src='3.3.3.3', dst='2.2.2.2')/ \
          UDP(sport=53, dport=udp_dst_port)/ \
          Raw(f'{msg_name}\x0012345678901234567890')

  parser = argparse.ArgumentParser()
  parser.add_argument('-iface_mac', dest="iface_mac", type=str, required=True,
                      help="From run_in_A3.py")
  parser.add_argument('-socket_port', dest="socket_port", type=str,
                      required=True, help="From run_in_A3.py")
  parser.add_argument('-v1_mac', dest="v1_mac", type=str, required=True,
                      help="From script")

  args, _ = parser.parse_known_args()
  iface_mac = args.iface_mac
  socket_port = int(args.socket_port)
  v1_mac = args.v1_mac

  print(f'Source port before NAT: {socket_port}')

  while True:
      pkts = sniff(iface='_v0', store=True, count=1, timeout=10)
      if 0 == len(pkts):
          print('Something failed, rerun the script :(', flush=True)
          break
      pkt = pkts[0]
      if not pkt.haslayer('UDP'):
          continue

      pkt_sport = pkt.getlayer('UDP').sport
      print(f'Source port after NAT: {pkt_sport}', flush=True)

      pkt_to_send = get_packet_to_send(pkt_sport, 'pkt_to_nat_port')
      sendp(pkt_to_send, '_v0', verbose=False) # Will not be received

      pkt_to_send = get_packet_to_send(socket_port, 'pkt_to_socket_port')
      sendp(pkt_to_send, '_v0', verbose=False)
      break

  $ cat run_in_A2.py
  import socket
  import netifaces

  print(f"{netifaces.ifaddresses('e00000')[netifaces.AF_LINK][0]['addr']}",
        flush=True)
  s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
  s.setsockopt(socket.SOL_SOCKET, socket.SO_BINDTODEVICE,
               str('vrf_1' + '\0').encode('utf-8'))
  s.connect(('3.3.3.3', 53))
  print(f'{s. getsockname()[1]}', flush=True)
  s.settimeout(5)

  while True:
      try:
          # Periodically send in order to keep the conntrack entry alive.
          s.send(b'a'*40)
          resp = s.recvfrom(1024)
          msg_name = resp[0].decode('utf-8').split('\0')[0]
          print(f"Got {msg_name}", flush=True)
      except Exception as e:
          pass

  $ cat repro.sh
  ip netns del A1 2> /dev/null
  ip netns del A2 2> /dev/null
  ip netns add A1
  ip netns add A2

  ip -n A1 link add _v0 type veth peer name _v1 netns A2
  ip -n A1 link set _v0 up

  ip -n A2 link add e00000 type bond
  ip -n A2 link add lo0 type dummy
  ip -n A2 link add vrf_1 type vrf table 10001
  ip -n A2 link set vrf_1 up
  ip -n A2 link set e00000 master vrf_1

  ip -n A2 addr add 1.1.1.1/24 dev e00000
  ip -n A2 link set e00000 up
  ip -n A2 link set _v1 master e00000
  ip -n A2 link set _v1 up
  ip -n A2 link set lo0 up
  ip -n A2 addr add 2.2.2.2/32 dev lo0

  ip -n A2 neigh add 1.1.1.10 lladdr 77:77:77:77:77:77 dev e00000
  ip -n A2 route add 3.3.3.3/32 via 1.1.1.10 dev e00000 table 10001

  ip netns exec A2 iptables -t nat -A POSTROUTING -p udp -m udp --dport 53 -j \
	SNAT --to-source 2.2.2.2 -o vrf_1

  sleep 5
  ip netns exec A2 python3 run_in_A2.py > x &
  XPID=$!
  sleep 5

  IFACE_MAC=`sed -n 1p x`
  SOCKET_PORT=`sed -n 2p x`
  V1_MAC=`ip -n A2 link show _v1 | sed -n 2p | awk '{print $2'}`
  ip netns exec A1 python3 run_in_A1.py -iface_mac ${IFACE_MAC} -socket_port \
          ${SOCKET_PORT} -v1_mac ${SOCKET_PORT}
  sleep 5

  kill -9 $XPID
  wait $XPID 2> /dev/null
  ip netns del A1
  ip netns del A2
  tail x -n 2
  rm x
  set +x

Fixes: 73e20b761a ("net: vrf: Add support for PREROUTING rules on vrf device")
Signed-off-by: Lahav Schlesinger <lschlesinger@drivenets.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Link: https://lore.kernel.org/r/20210815120002.2787653-1-lschlesinger@drivenets.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2021-08-16 16:37:01 -07:00

2055 lines
46 KiB
C
Raw Blame History

// 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/ethtool.h>
#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/spinlock_types.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 "1.1"
#define FIB_RULE_PREF 1000 /* default preference for FIB rules */
#define HT_MAP_BITS 4
#define HASH_INITVAL ((u32)0xcafef00d)
struct vrf_map {
DECLARE_HASHTABLE(ht, HT_MAP_BITS);
spinlock_t vmap_lock;
/* shared_tables:
* count how many distinct tables do not comply with the strict mode
* requirement.
* shared_tables value must be 0 in order to enable the strict mode.
*
* example of the evolution of shared_tables:
* | time
* add vrf0 --> table 100 shared_tables = 0 | t0
* add vrf1 --> table 101 shared_tables = 0 | t1
* add vrf2 --> table 100 shared_tables = 1 | t2
* add vrf3 --> table 100 shared_tables = 1 | t3
* add vrf4 --> table 101 shared_tables = 2 v t4
*
* shared_tables is a "step function" (or "staircase function")
* and it is increased by one when the second vrf is associated to a
* table.
*
* at t2, vrf0 and vrf2 are bound to table 100: shared_tables = 1.
*
* at t3, another dev (vrf3) is bound to the same table 100 but the
* value of shared_tables is still 1.
* This means that no matter how many new vrfs will register on the
* table 100, the shared_tables will not increase (considering only
* table 100).
*
* at t4, vrf4 is bound to table 101, and shared_tables = 2.
*
* Looking at the value of shared_tables we can immediately know if
* the strict_mode can or cannot be enforced. Indeed, strict_mode
* can be enforced iff shared_tables = 0.
*
* Conversely, shared_tables is decreased when a vrf is de-associated
* from a table with exactly two associated vrfs.
*/
u32 shared_tables;
bool strict_mode;
};
struct vrf_map_elem {
struct hlist_node hnode;
struct list_head vrf_list; /* VRFs registered to this table */
u32 table_id;
int users;
int ifindex;
};
static unsigned int vrf_net_id;
/* per netns vrf data */
struct netns_vrf {
/* protected by rtnl lock */
bool add_fib_rules;
struct vrf_map vmap;
struct ctl_table_header *ctl_hdr;
};
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 list_head me_list; /* entry in vrf_map_elem */
int ifindex;
};
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;
}
}
static struct vrf_map *netns_vrf_map(struct net *net)
{
struct netns_vrf *nn_vrf = net_generic(net, vrf_net_id);
return &nn_vrf->vmap;
}
static struct vrf_map *netns_vrf_map_by_dev(struct net_device *dev)
{
return netns_vrf_map(dev_net(dev));
}
static int vrf_map_elem_get_vrf_ifindex(struct vrf_map_elem *me)
{
struct list_head *me_head = &me->vrf_list;
struct net_vrf *vrf;
if (list_empty(me_head))
return -ENODEV;
vrf = list_first_entry(me_head, struct net_vrf, me_list);
return vrf->ifindex;
}
static struct vrf_map_elem *vrf_map_elem_alloc(gfp_t flags)
{
struct vrf_map_elem *me;
me = kmalloc(sizeof(*me), flags);
if (!me)
return NULL;
return me;
}
static void vrf_map_elem_free(struct vrf_map_elem *me)
{
kfree(me);
}
static void vrf_map_elem_init(struct vrf_map_elem *me, int table_id,
int ifindex, int users)
{
me->table_id = table_id;
me->ifindex = ifindex;
me->users = users;
INIT_LIST_HEAD(&me->vrf_list);
}
static struct vrf_map_elem *vrf_map_lookup_elem(struct vrf_map *vmap,
u32 table_id)
{
struct vrf_map_elem *me;
u32 key;
key = jhash_1word(table_id, HASH_INITVAL);
hash_for_each_possible(vmap->ht, me, hnode, key) {
if (me->table_id == table_id)
return me;
}
return NULL;
}
static void vrf_map_add_elem(struct vrf_map *vmap, struct vrf_map_elem *me)
{
u32 table_id = me->table_id;
u32 key;
key = jhash_1word(table_id, HASH_INITVAL);
hash_add(vmap->ht, &me->hnode, key);
}
static void vrf_map_del_elem(struct vrf_map_elem *me)
{
hash_del(&me->hnode);
}
static void vrf_map_lock(struct vrf_map *vmap) __acquires(&vmap->vmap_lock)
{
spin_lock(&vmap->vmap_lock);
}
static void vrf_map_unlock(struct vrf_map *vmap) __releases(&vmap->vmap_lock)
{
spin_unlock(&vmap->vmap_lock);
}
/* called with rtnl lock held */
static int
vrf_map_register_dev(struct net_device *dev, struct netlink_ext_ack *extack)
{
struct vrf_map *vmap = netns_vrf_map_by_dev(dev);
struct net_vrf *vrf = netdev_priv(dev);
struct vrf_map_elem *new_me, *me;
u32 table_id = vrf->tb_id;
bool free_new_me = false;
int users;
int res;
/* we pre-allocate elements used in the spin-locked section (so that we
* keep the spinlock as short as possible).
*/
new_me = vrf_map_elem_alloc(GFP_KERNEL);
if (!new_me)
return -ENOMEM;
vrf_map_elem_init(new_me, table_id, dev->ifindex, 0);
vrf_map_lock(vmap);
me = vrf_map_lookup_elem(vmap, table_id);
if (!me) {
me = new_me;
vrf_map_add_elem(vmap, me);
goto link_vrf;
}
/* we already have an entry in the vrf_map, so it means there is (at
* least) a vrf registered on the specific table.
*/
free_new_me = true;
if (vmap->strict_mode) {
/* vrfs cannot share the same table */
NL_SET_ERR_MSG(extack, "Table is used by another VRF");
res = -EBUSY;
goto unlock;
}
link_vrf:
users = ++me->users;
if (users == 2)
++vmap->shared_tables;
list_add(&vrf->me_list, &me->vrf_list);
res = 0;
unlock:
vrf_map_unlock(vmap);
/* clean-up, if needed */
if (free_new_me)
vrf_map_elem_free(new_me);
return res;
}
/* called with rtnl lock held */
static void vrf_map_unregister_dev(struct net_device *dev)
{
struct vrf_map *vmap = netns_vrf_map_by_dev(dev);
struct net_vrf *vrf = netdev_priv(dev);
u32 table_id = vrf->tb_id;
struct vrf_map_elem *me;
int users;
vrf_map_lock(vmap);
me = vrf_map_lookup_elem(vmap, table_id);
if (!me)
goto unlock;
list_del(&vrf->me_list);
users = --me->users;
if (users == 1) {
--vmap->shared_tables;
} else if (users == 0) {
vrf_map_del_elem(me);
/* no one will refer to this element anymore */
vrf_map_elem_free(me);
}
unlock:
vrf_map_unlock(vmap);
}
/* return the vrf device index associated with the table_id */
static int vrf_ifindex_lookup_by_table_id(struct net *net, u32 table_id)
{
struct vrf_map *vmap = netns_vrf_map(net);
struct vrf_map_elem *me;
int ifindex;
vrf_map_lock(vmap);
if (!vmap->strict_mode) {
ifindex = -EPERM;
goto unlock;
}
me = vrf_map_lookup_elem(vmap, table_id);
if (!me) {
ifindex = -ENODEV;
goto unlock;
}
ifindex = vrf_map_elem_get_vrf_ifindex(me);
unlock:
vrf_map_unlock(vmap);
return ifindex;
}
/* 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;
struct net *net = dev_net(skb->dev);
struct flowi6 fl6;
int ret = NET_XMIT_DROP;
struct dst_entry *dst;
struct dst_entry *dst_null = &net->ipv6.ip6_null_entry->dst;
if (!pskb_may_pull(skb, ETH_HLEN + sizeof(struct ipv6hdr)))
goto err;
iph = ipv6_hdr(skb);
memset(&fl6, 0, sizeof(fl6));
/* needed to match OIF rule */
fl6.flowi6_oif = dev->ifindex;
fl6.flowi6_iif = LOOPBACK_IFINDEX;
fl6.daddr = iph->daddr;
fl6.saddr = iph->saddr;
fl6.flowlabel = ip6_flowinfo(iph);
fl6.flowi6_mark = skb->mark;
fl6.flowi6_proto = iph->nexthdr;
fl6.flowi6_flags = FLOWI_FLAG_SKIP_NH_OIF;
dst = ip6_dst_lookup_flow(net, NULL, &fl6, NULL);
if (IS_ERR(dst) || dst == dst_null)
goto err;
skb_dst_drop(skb);
/* if dst.dev is 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;
int ret = NET_XMIT_DROP;
struct flowi4 fl4;
struct net *net = dev_net(vrf_dev);
struct rtable *rt;
if (!pskb_may_pull(skb, ETH_HLEN + sizeof(struct iphdr)))
goto err;
ip4h = ip_hdr(skb);
memset(&fl4, 0, sizeof(fl4));
/* needed to match OIF rule */
fl4.flowi4_oif = vrf_dev->ifindex;
fl4.flowi4_iif = LOOPBACK_IFINDEX;
fl4.flowi4_tos = RT_TOS(ip4h->tos);
fl4.flowi4_flags = FLOWI_FLAG_ANYSRC | FLOWI_FLAG_SKIP_NH_OIF;
fl4.flowi4_proto = ip4h->protocol;
fl4.daddr = ip4h->daddr;
fl4.saddr = ip4h->saddr;
rt = ip_route_output_flow(net, &fl4, NULL);
if (IS_ERR(rt))
goto err;
skb_dst_drop(skb);
/* if dst.dev is 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 void vrf_finish_direct(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);
}
/* reset skb device */
nf_reset_ct(skb);
}
#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;
const struct in6_addr *nexthop;
struct neighbour *neigh;
int ret;
nf_reset_ct(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_finish(struct net *net, struct sock *sk,
struct sk_buff *skb)
{
vrf_finish_direct(skb);
return vrf_ip6_local_out(net, sk, skb);
}
static int vrf_output6_direct(struct net *net, struct sock *sk,
struct sk_buff *skb)
{
int err = 1;
skb->protocol = htons(ETH_P_IPV6);
if (!(IPCB(skb)->flags & IPSKB_REROUTED))
err = nf_hook(NFPROTO_IPV6, NF_INET_POST_ROUTING, net, sk, skb,
NULL, skb->dev, vrf_output6_direct_finish);
if (likely(err == 1))
vrf_finish_direct(skb);
return err;
}
static int vrf_ip6_out_direct_finish(struct net *net, struct sock *sk,
struct sk_buff *skb)
{
int err;
err = vrf_output6_direct(net, sk, skb);
if (likely(err == 1))
err = vrf_ip6_local_out(net, sk, skb);
return err;
}
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_ip6_out_direct_finish);
if (likely(err == 1))
err = vrf_output6_direct(net, sk, skb);
if (likely(err == 1))
return skb;
return NULL;
}
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) ||
IP6CB(skb)->flags & IP6SKB_XFRM_TRANSFORMED)
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_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_ct(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_finish(struct net *net, struct sock *sk,
struct sk_buff *skb)
{
vrf_finish_direct(skb);
return vrf_ip_local_out(net, sk, skb);
}
static int vrf_output_direct(struct net *net, struct sock *sk,
struct sk_buff *skb)
{
int err = 1;
skb->protocol = htons(ETH_P_IP);
if (!(IPCB(skb)->flags & IPSKB_REROUTED))
err = nf_hook(NFPROTO_IPV4, NF_INET_POST_ROUTING, net, sk, skb,
NULL, skb->dev, vrf_output_direct_finish);
if (likely(err == 1))
vrf_finish_direct(skb);
return err;
}
static int vrf_ip_out_direct_finish(struct net *net, struct sock *sk,
struct sk_buff *skb)
{
int err;
err = vrf_output_direct(net, sk, skb);
if (likely(err == 1))
err = vrf_ip_local_out(net, sk, skb);
return err;
}
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_ip_out_direct_finish);
if (likely(err == 1))
err = vrf_output_direct(net, sk, skb);
if (likely(err == 1))
return skb;
return NULL;
}
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) ||
IPCB(skb)->flags & IPSKB_XFRM_TRANSFORMED)
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);
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;
/* 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;
}
static int vrf_prepare_mac_header(struct sk_buff *skb,
struct net_device *vrf_dev, u16 proto)
{
struct ethhdr *eth;
int err;
/* in general, we do not know if there is enough space in the head of
* the packet for hosting the mac header.
*/
err = skb_cow_head(skb, LL_RESERVED_SPACE(vrf_dev));
if (unlikely(err))
/* no space in the skb head */
return -ENOBUFS;
__skb_push(skb, ETH_HLEN);
eth = (struct ethhdr *)skb->data;
skb_reset_mac_header(skb);
/* we set the ethernet destination and the source addresses to the
* address of the VRF device.
*/
ether_addr_copy(eth->h_dest, vrf_dev->dev_addr);
ether_addr_copy(eth->h_source, vrf_dev->dev_addr);
eth->h_proto = htons(proto);
/* the destination address of the Ethernet frame corresponds to the
* address set on the VRF interface; therefore, the packet is intended
* to be processed locally.
*/
skb->protocol = eth->h_proto;
skb->pkt_type = PACKET_HOST;
skb_postpush_rcsum(skb, skb->data, ETH_HLEN);
skb_pull_inline(skb, ETH_HLEN);
return 0;
}
/* prepare and add the mac header to the packet if it was not set previously.
* In this way, packet sniffers such as tcpdump can parse the packet correctly.
* If the mac header was already set, the original mac header is left
* untouched and the function returns immediately.
*/
static int vrf_add_mac_header_if_unset(struct sk_buff *skb,
struct net_device *vrf_dev,
u16 proto)
{
if (skb_mac_header_was_set(skb))
return 0;
return vrf_prepare_mac_header(skb, vrf_dev, proto);
}
#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);
nf_reset_ct(skb);
/* loopback, multicast & non-ND link-local traffic; do not push through
* packet taps again. Reset pkt_type for upper layers to process skb.
* For strict packets with a source LLA, determine the dst using the
* original ifindex.
*/
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;
else if (ipv6_addr_type(&ipv6_hdr(skb)->saddr) & IPV6_ADDR_LINKLOCAL)
vrf_ip6_input_dst(skb, vrf_dev, orig_iif);
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)) {
int err;
err = vrf_add_mac_header_if_unset(skb, vrf_dev,
ETH_P_IPV6);
if (likely(!err)) {
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;
nf_reset_ct(skb);
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)) {
int err;
err = vrf_add_mac_header_if_unset(skb, vrf_dev, ETH_P_IP);
if (likely(!err)) {
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
* Note: Caller to this function must hold rcu_read_lock() and no refcnt
* is taken on the dst by this function.
*/
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 | RT6_LOOKUP_F_DST_NOREF;
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;
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 || family == RTNL_FAMILY_IP6MR) &&
!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 = IP6_MAX_MTU;
dev->mtu = dev->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);
vrf_map_unregister_dev(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);
struct netns_vrf *nn_vrf;
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;
/* mapping between table_id and vrf;
* note: such binding could not be done in the dev init function
* because dev->ifindex id is not available yet.
*/
vrf->ifindex = dev->ifindex;
err = vrf_map_register_dev(dev, extack);
if (err) {
unregister_netdevice(dev);
goto out;
}
net = dev_net(dev);
nn_vrf = net_generic(net, vrf_net_id);
add_fib_rules = &nn_vrf->add_fib_rules;
if (*add_fib_rules) {
err = vrf_add_fib_rules(dev);
if (err) {
vrf_map_unregister_dev(dev);
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,
};
static int vrf_map_init(struct vrf_map *vmap)
{
spin_lock_init(&vmap->vmap_lock);
hash_init(vmap->ht);
vmap->strict_mode = false;
return 0;
}
#ifdef CONFIG_SYSCTL
static bool vrf_strict_mode(struct vrf_map *vmap)
{
bool strict_mode;
vrf_map_lock(vmap);
strict_mode = vmap->strict_mode;
vrf_map_unlock(vmap);
return strict_mode;
}
static int vrf_strict_mode_change(struct vrf_map *vmap, bool new_mode)
{
bool *cur_mode;
int res = 0;
vrf_map_lock(vmap);
cur_mode = &vmap->strict_mode;
if (*cur_mode == new_mode)
goto unlock;
if (*cur_mode) {
/* disable strict mode */
*cur_mode = false;
} else {
if (vmap->shared_tables) {
/* we cannot allow strict_mode because there are some
* vrfs that share one or more tables.
*/
res = -EBUSY;
goto unlock;
}
/* no tables are shared among vrfs, so we can go back
* to 1:1 association between a vrf with its table.
*/
*cur_mode = true;
}
unlock:
vrf_map_unlock(vmap);
return res;
}
static int vrf_shared_table_handler(struct ctl_table *table, int write,
void *buffer, size_t *lenp, loff_t *ppos)
{
struct net *net = (struct net *)table->extra1;
struct vrf_map *vmap = netns_vrf_map(net);
int proc_strict_mode = 0;
struct ctl_table tmp = {
.procname = table->procname,
.data = &proc_strict_mode,
.maxlen = sizeof(int),
.mode = table->mode,
.extra1 = SYSCTL_ZERO,
.extra2 = SYSCTL_ONE,
};
int ret;
if (!write)
proc_strict_mode = vrf_strict_mode(vmap);
ret = proc_dointvec_minmax(&tmp, write, buffer, lenp, ppos);
if (write && ret == 0)
ret = vrf_strict_mode_change(vmap, (bool)proc_strict_mode);
return ret;
}
static const struct ctl_table vrf_table[] = {
{
.procname = "strict_mode",
.data = NULL,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = vrf_shared_table_handler,
/* set by the vrf_netns_init */
.extra1 = NULL,
},
{ },
};
static int vrf_netns_init_sysctl(struct net *net, struct netns_vrf *nn_vrf)
{
struct ctl_table *table;
table = kmemdup(vrf_table, sizeof(vrf_table), GFP_KERNEL);
if (!table)
return -ENOMEM;
/* init the extra1 parameter with the reference to current netns */
table[0].extra1 = net;
nn_vrf->ctl_hdr = register_net_sysctl(net, "net/vrf", table);
if (!nn_vrf->ctl_hdr) {
kfree(table);
return -ENOMEM;
}
return 0;
}
static void vrf_netns_exit_sysctl(struct net *net)
{
struct netns_vrf *nn_vrf = net_generic(net, vrf_net_id);
struct ctl_table *table;
table = nn_vrf->ctl_hdr->ctl_table_arg;
unregister_net_sysctl_table(nn_vrf->ctl_hdr);
kfree(table);
}
#else
static int vrf_netns_init_sysctl(struct net *net, struct netns_vrf *nn_vrf)
{
return 0;
}
static void vrf_netns_exit_sysctl(struct net *net)
{
}
#endif
/* Initialize per network namespace state */
static int __net_init vrf_netns_init(struct net *net)
{
struct netns_vrf *nn_vrf = net_generic(net, vrf_net_id);
nn_vrf->add_fib_rules = true;
vrf_map_init(&nn_vrf->vmap);
return vrf_netns_init_sysctl(net, nn_vrf);
}
static void __net_exit vrf_netns_exit(struct net *net)
{
vrf_netns_exit_sysctl(net);
}
static struct pernet_operations vrf_net_ops __net_initdata = {
.init = vrf_netns_init,
.exit = vrf_netns_exit,
.id = &vrf_net_id,
.size = sizeof(struct netns_vrf),
};
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 = l3mdev_table_lookup_register(L3MDEV_TYPE_VRF,
vrf_ifindex_lookup_by_table_id);
if (rc < 0)
goto unreg_pernet;
rc = rtnl_link_register(&vrf_link_ops);
if (rc < 0)
goto table_lookup_unreg;
return 0;
table_lookup_unreg:
l3mdev_table_lookup_unregister(L3MDEV_TYPE_VRF,
vrf_ifindex_lookup_by_table_id);
unreg_pernet:
unregister_pernet_subsys(&vrf_net_ops);
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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