blob: 488c6f50df736968cee60af48d0360924a9f2e2b [file] [log] [blame]
/*
* vrf.c: device driver to encapsulate a VRF space
*
* Copyright (c) 2015 Cumulus Networks. All rights reserved.
* Copyright (c) 2015 Shrijeet Mukherjee <shm@cumulusnetworks.com>
* Copyright (c) 2015 David Ahern <dsa@cumulusnetworks.com>
*
* Based on dummy, team and ipvlan drivers
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*/
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/ip.h>
#include <linux/init.h>
#include <linux/moduleparam.h>
#include <linux/netfilter.h>
#include <linux/rtnetlink.h>
#include <net/rtnetlink.h>
#include <linux/u64_stats_sync.h>
#include <linux/hashtable.h>
#include <linux/inetdevice.h>
#include <net/arp.h>
#include <net/ip.h>
#include <net/ip_fib.h>
#include <net/ip6_route.h>
#include <net/rtnetlink.h>
#include <net/route.h>
#include <net/addrconf.h>
#include <net/vrf.h>
#define DRV_NAME "vrf"
#define DRV_VERSION "1.0"
#define vrf_is_slave(dev) ((dev)->flags & IFF_SLAVE)
#define vrf_master_get_rcu(dev) \
((struct net_device *)rcu_dereference(dev->rx_handler_data))
struct pcpu_dstats {
u64 tx_pkts;
u64 tx_bytes;
u64 tx_drps;
u64 rx_pkts;
u64 rx_bytes;
struct u64_stats_sync syncp;
};
static struct dst_entry *vrf_ip_check(struct dst_entry *dst, u32 cookie)
{
return dst;
}
static int vrf_ip_local_out(struct sk_buff *skb)
{
return ip_local_out(skb);
}
static unsigned int vrf_v4_mtu(const struct dst_entry *dst)
{
/* TO-DO: return max ethernet size? */
return dst->dev->mtu;
}
static void vrf_dst_destroy(struct dst_entry *dst)
{
/* our dst lives forever - or until the device is closed */
}
static unsigned int vrf_default_advmss(const struct dst_entry *dst)
{
return 65535 - 40;
}
static struct dst_ops vrf_dst_ops = {
.family = AF_INET,
.local_out = vrf_ip_local_out,
.check = vrf_ip_check,
.mtu = vrf_v4_mtu,
.destroy = vrf_dst_destroy,
.default_advmss = vrf_default_advmss,
};
static bool is_ip_rx_frame(struct sk_buff *skb)
{
switch (skb->protocol) {
case htons(ETH_P_IP):
case htons(ETH_P_IPV6):
return true;
}
return false;
}
static void vrf_tx_error(struct net_device *vrf_dev, struct sk_buff *skb)
{
vrf_dev->stats.tx_errors++;
kfree_skb(skb);
}
/* note: already called with rcu_read_lock */
static rx_handler_result_t vrf_handle_frame(struct sk_buff **pskb)
{
struct sk_buff *skb = *pskb;
if (is_ip_rx_frame(skb)) {
struct net_device *dev = vrf_master_get_rcu(skb->dev);
struct pcpu_dstats *dstats = this_cpu_ptr(dev->dstats);
u64_stats_update_begin(&dstats->syncp);
dstats->rx_pkts++;
dstats->rx_bytes += skb->len;
u64_stats_update_end(&dstats->syncp);
skb->dev = dev;
return RX_HANDLER_ANOTHER;
}
return RX_HANDLER_PASS;
}
static struct rtnl_link_stats64 *vrf_get_stats64(struct net_device *dev,
struct rtnl_link_stats64 *stats)
{
int i;
for_each_possible_cpu(i) {
const struct pcpu_dstats *dstats;
u64 tbytes, tpkts, tdrops, rbytes, rpkts;
unsigned int start;
dstats = per_cpu_ptr(dev->dstats, i);
do {
start = u64_stats_fetch_begin_irq(&dstats->syncp);
tbytes = dstats->tx_bytes;
tpkts = dstats->tx_pkts;
tdrops = dstats->tx_drps;
rbytes = dstats->rx_bytes;
rpkts = dstats->rx_pkts;
} while (u64_stats_fetch_retry_irq(&dstats->syncp, start));
stats->tx_bytes += tbytes;
stats->tx_packets += tpkts;
stats->tx_dropped += tdrops;
stats->rx_bytes += rbytes;
stats->rx_packets += rpkts;
}
return stats;
}
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;
}
static int vrf_send_v4_prep(struct sk_buff *skb, struct flowi4 *fl4,
struct net_device *vrf_dev)
{
struct rtable *rt;
int err = 1;
rt = ip_route_output_flow(dev_net(vrf_dev), fl4, NULL);
if (IS_ERR(rt))
goto out;
/* TO-DO: what about broadcast ? */
if (rt->rt_type != RTN_UNICAST && rt->rt_type != RTN_LOCAL) {
ip_rt_put(rt);
goto out;
}
skb_dst_drop(skb);
skb_dst_set(skb, &rt->dst);
err = 0;
out:
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_VRFSRC |
FLOWI_FLAG_SKIP_NH_OIF,
.daddr = ip4h->daddr,
};
if (vrf_send_v4_prep(skb, &fl4, vrf_dev))
goto err;
if (!ip4h->saddr) {
ip4h->saddr = inet_select_addr(skb_dst(skb)->dev, 0,
RT_SCOPE_LINK);
}
ret = ip_local_out(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)
{
/* strip the ethernet header added for pass through VRF device */
__skb_pull(skb, skb_network_offset(skb));
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)
{
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 += skb->len;
u64_stats_update_end(&dstats->syncp);
} else {
this_cpu_inc(dev->dstats->tx_drps);
}
return ret;
}
/* modelled after ip_finish_output2 */
static int vrf_finish_output(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;
u32 nexthop;
int ret = -EINVAL;
/* 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();
nexthop = (__force u32)rt_nexthop(rt, ip_hdr(skb)->daddr);
neigh = __ipv4_neigh_lookup_noref(dev, nexthop);
if (unlikely(!neigh))
neigh = __neigh_create(&arp_tbl, &nexthop, dev, false);
if (!IS_ERR(neigh))
ret = dst_neigh_output(dst, neigh, skb);
rcu_read_unlock_bh();
err:
if (unlikely(ret < 0))
vrf_tx_error(skb->dev, skb);
return ret;
}
static int vrf_output(struct sock *sk, struct sk_buff *skb)
{
struct net_device *dev = skb_dst(skb)->dev;
IP_UPD_PO_STATS(dev_net(dev), IPSTATS_MIB_OUT, skb->len);
skb->dev = dev;
skb->protocol = htons(ETH_P_IP);
return NF_HOOK_COND(NFPROTO_IPV4, NF_INET_POST_ROUTING, sk, skb,
NULL, dev,
vrf_finish_output,
!(IPCB(skb)->flags & IPSKB_REROUTED));
}
static void vrf_rtable_destroy(struct net_vrf *vrf)
{
struct dst_entry *dst = (struct dst_entry *)vrf->rth;
dst_destroy(dst);
vrf->rth = NULL;
}
static struct rtable *vrf_rtable_create(struct net_device *dev)
{
struct rtable *rth;
rth = dst_alloc(&vrf_dst_ops, dev, 2,
DST_OBSOLETE_NONE,
(DST_HOST | DST_NOPOLICY | DST_NOXFRM));
if (rth) {
rth->dst.output = vrf_output;
rth->rt_genid = rt_genid_ipv4(dev_net(dev));
rth->rt_flags = 0;
rth->rt_type = RTN_UNICAST;
rth->rt_is_input = 0;
rth->rt_iif = 0;
rth->rt_pmtu = 0;
rth->rt_gateway = 0;
rth->rt_uses_gateway = 0;
INIT_LIST_HEAD(&rth->rt_uncached);
rth->rt_uncached_list = NULL;
}
return rth;
}
/**************************** device handling ********************/
/* cycle interface to flush neighbor cache and move routes across tables */
static void cycle_netdev(struct net_device *dev)
{
unsigned int flags = dev->flags;
int ret;
if (!netif_running(dev))
return;
ret = dev_change_flags(dev, flags & ~IFF_UP);
if (ret >= 0)
ret = dev_change_flags(dev, flags);
if (ret < 0) {
netdev_err(dev,
"Failed to cycle device %s; route tables might be wrong!\n",
dev->name);
}
}
static struct slave *__vrf_find_slave_dev(struct slave_queue *queue,
struct net_device *dev)
{
struct list_head *head = &queue->all_slaves;
struct slave *slave;
list_for_each_entry(slave, head, list) {
if (slave->dev == dev)
return slave;
}
return NULL;
}
/* inverse of __vrf_insert_slave */
static void __vrf_remove_slave(struct slave_queue *queue, struct slave *slave)
{
list_del(&slave->list);
}
static void __vrf_insert_slave(struct slave_queue *queue, struct slave *slave)
{
list_add(&slave->list, &queue->all_slaves);
}
static int do_vrf_add_slave(struct net_device *dev, struct net_device *port_dev)
{
struct net_vrf_dev *vrf_ptr = kmalloc(sizeof(*vrf_ptr), GFP_KERNEL);
struct slave *slave = kzalloc(sizeof(*slave), GFP_KERNEL);
struct net_vrf *vrf = netdev_priv(dev);
struct slave_queue *queue = &vrf->queue;
int ret = -ENOMEM;
if (!slave || !vrf_ptr)
goto out_fail;
slave->dev = port_dev;
vrf_ptr->ifindex = dev->ifindex;
vrf_ptr->tb_id = vrf->tb_id;
/* register the packet handler for slave ports */
ret = netdev_rx_handler_register(port_dev, vrf_handle_frame, dev);
if (ret) {
netdev_err(port_dev,
"Device %s failed to register rx_handler\n",
port_dev->name);
goto out_fail;
}
ret = netdev_master_upper_dev_link(port_dev, dev);
if (ret < 0)
goto out_unregister;
port_dev->flags |= IFF_SLAVE;
__vrf_insert_slave(queue, slave);
rcu_assign_pointer(port_dev->vrf_ptr, vrf_ptr);
cycle_netdev(port_dev);
return 0;
out_unregister:
netdev_rx_handler_unregister(port_dev);
out_fail:
kfree(vrf_ptr);
kfree(slave);
return ret;
}
static int vrf_add_slave(struct net_device *dev, struct net_device *port_dev)
{
if (netif_is_vrf(port_dev) || vrf_is_slave(port_dev))
return -EINVAL;
return do_vrf_add_slave(dev, port_dev);
}
/* inverse of do_vrf_add_slave */
static int do_vrf_del_slave(struct net_device *dev, struct net_device *port_dev)
{
struct net_vrf_dev *vrf_ptr = rtnl_dereference(port_dev->vrf_ptr);
struct net_vrf *vrf = netdev_priv(dev);
struct slave_queue *queue = &vrf->queue;
struct slave *slave;
RCU_INIT_POINTER(port_dev->vrf_ptr, NULL);
netdev_upper_dev_unlink(port_dev, dev);
port_dev->flags &= ~IFF_SLAVE;
netdev_rx_handler_unregister(port_dev);
/* after netdev_rx_handler_unregister for synchronize_rcu */
kfree(vrf_ptr);
cycle_netdev(port_dev);
slave = __vrf_find_slave_dev(queue, port_dev);
if (slave)
__vrf_remove_slave(queue, slave);
kfree(slave);
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);
struct slave_queue *queue = &vrf->queue;
struct list_head *head = &queue->all_slaves;
struct slave *slave, *next;
vrf_rtable_destroy(vrf);
list_for_each_entry_safe(slave, next, head, list)
vrf_del_slave(dev, slave->dev);
free_percpu(dev->dstats);
dev->dstats = NULL;
}
static int vrf_dev_init(struct net_device *dev)
{
struct net_vrf *vrf = netdev_priv(dev);
INIT_LIST_HEAD(&vrf->queue.all_slaves);
dev->dstats = netdev_alloc_pcpu_stats(struct pcpu_dstats);
if (!dev->dstats)
goto out_nomem;
/* create the default dst which points back to us */
vrf->rth = vrf_rtable_create(dev);
if (!vrf->rth)
goto out_stats;
dev->flags = IFF_MASTER | IFF_NOARP;
return 0;
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_get_stats64 = vrf_get_stats64,
.ndo_add_slave = vrf_add_slave,
.ndo_del_slave = vrf_del_slave,
};
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 void vrf_setup(struct net_device *dev)
{
ether_setup(dev);
/* Initialize the device structure. */
dev->netdev_ops = &vrf_netdev_ops;
dev->ethtool_ops = &vrf_ethtool_ops;
dev->destructor = free_netdev;
/* 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;
}
static int vrf_validate(struct nlattr *tb[], struct nlattr *data[])
{
if (tb[IFLA_ADDRESS]) {
if (nla_len(tb[IFLA_ADDRESS]) != ETH_ALEN)
return -EINVAL;
if (!is_valid_ether_addr(nla_data(tb[IFLA_ADDRESS])))
return -EADDRNOTAVAIL;
}
return 0;
}
static void vrf_dellink(struct net_device *dev, struct list_head *head)
{
struct net_vrf_dev *vrf_ptr = rtnl_dereference(dev->vrf_ptr);
RCU_INIT_POINTER(dev->vrf_ptr, NULL);
kfree_rcu(vrf_ptr, rcu);
unregister_netdevice_queue(dev, head);
}
static int vrf_newlink(struct net *src_net, struct net_device *dev,
struct nlattr *tb[], struct nlattr *data[])
{
struct net_vrf *vrf = netdev_priv(dev);
struct net_vrf_dev *vrf_ptr;
int err;
if (!data || !data[IFLA_VRF_TABLE])
return -EINVAL;
vrf->tb_id = nla_get_u32(data[IFLA_VRF_TABLE]);
dev->priv_flags |= IFF_VRF_MASTER;
err = -ENOMEM;
vrf_ptr = kmalloc(sizeof(*dev->vrf_ptr), GFP_KERNEL);
if (!vrf_ptr)
goto out_fail;
vrf_ptr->ifindex = dev->ifindex;
vrf_ptr->tb_id = vrf->tb_id;
err = register_netdevice(dev);
if (err < 0)
goto out_fail;
rcu_assign_pointer(dev->vrf_ptr, vrf_ptr);
return 0;
out_fail:
kfree(vrf_ptr);
free_netdev(dev);
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 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,
.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_vrf_dev *vrf_ptr = rtnl_dereference(dev->vrf_ptr);
struct net_device *vrf_dev;
if (!vrf_ptr || netif_is_vrf(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 __init vrf_init_module(void)
{
int rc;
vrf_dst_ops.kmem_cachep =
kmem_cache_create("vrf_ip_dst_cache",
sizeof(struct rtable), 0,
SLAB_HWCACHE_ALIGN,
NULL);
if (!vrf_dst_ops.kmem_cachep)
return -ENOMEM;
register_netdevice_notifier(&vrf_notifier_block);
rc = rtnl_link_register(&vrf_link_ops);
if (rc < 0)
goto error;
return 0;
error:
unregister_netdevice_notifier(&vrf_notifier_block);
kmem_cache_destroy(vrf_dst_ops.kmem_cachep);
return rc;
}
static void __exit vrf_cleanup_module(void)
{
rtnl_link_unregister(&vrf_link_ops);
unregister_netdevice_notifier(&vrf_notifier_block);
kmem_cache_destroy(vrf_dst_ops.kmem_cachep);
}
module_init(vrf_init_module);
module_exit(vrf_cleanup_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);