diff options
Diffstat (limited to 'drivers/net/vrf.c')
| -rw-r--r-- | drivers/net/vrf.c | 710 |
1 files changed, 710 insertions, 0 deletions
diff --git a/drivers/net/vrf.c b/drivers/net/vrf.c new file mode 100644 index 0000000..e7094fb --- /dev/null +++ b/drivers/net/vrf.c @@ -0,0 +1,710 @@ +/* + * 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, + .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); |
