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vrf.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/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 possibile).
*/
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 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;
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 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 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;