qed: Add link support

[deliverable/linux.git] / drivers / net / vrf.c

/*
 * 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_fib.h>
#include <net/ip6_route.h>
#include <net/rtnetlink.h>
#include <net/route.h>
#include <net/addrconf.h>
#include <net/l3mdev.h>

#define RT_FL_TOS(oldflp4) \
        ((oldflp4)->flowi4_tos & (IPTOS_RT_MASK | RTO_ONLINK))

#define DRV_NAME        "vrf"
#define DRV_VERSION     "1.0"

#define vrf_master_get_rcu(dev) \
        ((struct net_device *)rcu_dereference(dev->rx_handler_data))

struct slave {
        struct list_head        list;
        struct net_device       *dev;
};

struct slave_queue {
        struct list_head        all_slaves;
};

struct net_vrf {
        struct slave_queue      queue;
        struct rtable           *rth;
        struct rt6_info         *rt6;
        u32                     tb_id;
};

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 net *net, struct sock *sk, struct sk_buff *skb)
{
        return ip_local_out(net, sk, 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,
};

/* 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.
 */
#if IS_ENABLED(CONFIG_IPV6)
static bool check_ipv6_frame(const struct sk_buff *skb)
{
        const struct ipv6hdr *ipv6h = (struct ipv6hdr *)skb->data;
        size_t hlen = sizeof(*ipv6h);
        bool rc = true;

        if (skb->len < hlen)
                goto out;

        if (ipv6h->nexthdr == NEXTHDR_ICMP) {
                const struct icmp6hdr *icmph;

                if (skb->len < hlen + sizeof(*icmph))
                        goto out;

                icmph = (struct icmp6hdr *)(skb->data + sizeof(*ipv6h));
                switch (icmph->icmp6_type) {
                case NDISC_ROUTER_SOLICITATION:
                case NDISC_ROUTER_ADVERTISEMENT:
                case NDISC_NEIGHBOUR_SOLICITATION:
                case NDISC_NEIGHBOUR_ADVERTISEMENT:
                case NDISC_REDIRECT:
                        rc = false;
                        break;
                }
        }

out:
        return rc;
}
#else
static bool check_ipv6_frame(const struct sk_buff *skb)
{
        return false;
}
#endif

static bool is_ip_rx_frame(struct sk_buff *skb)
{
        switch (skb->protocol) {
        case htons(ETH_P_IP):
                return true;
        case htons(ETH_P_IPV6):
                return check_ipv6_frame(skb);
        }
        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;
}

#if IS_ENABLED(CONFIG_IPV6)
static netdev_tx_t vrf_process_v6_outbound(struct sk_buff *skb,
                                           struct net_device *dev)
{
        const struct ipv6hdr *iph = ipv6_hdr(skb);
        struct net *net = dev_net(skb->dev);
        struct flowi6 fl6 = {
                /* needed to match OIF rule */
                .flowi6_oif = dev->ifindex,
                .flowi6_iif = LOOPBACK_IFINDEX,
                .daddr = iph->daddr,
                .saddr = iph->saddr,
                .flowlabel = ip6_flowinfo(iph),
                .flowi6_mark = skb->mark,
                .flowi6_proto = iph->nexthdr,
                .flowi6_flags = FLOWI_FLAG_L3MDEV_SRC | FLOWI_FLAG_SKIP_NH_OIF,
        };
        int ret = NET_XMIT_DROP;
        struct dst_entry *dst;
        struct dst_entry *dst_null = &net->ipv6.ip6_null_entry->dst;

        dst = ip6_route_output(net, NULL, &fl6);
        if (dst == dst_null)
                goto err;

        skb_dst_drop(skb);
        skb_dst_set(skb, dst);

        ret = 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

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_L3MDEV_SRC |
                                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(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)
{
        /* 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;
}

#if IS_ENABLED(CONFIG_IPV6)
static struct dst_entry *vrf_ip6_check(struct dst_entry *dst, u32 cookie)
{
        return dst;
}

static struct dst_ops vrf_dst_ops6 = {
        .family         = AF_INET6,
        .local_out      = ip6_local_out,
        .check          = vrf_ip6_check,
        .mtu            = vrf_v4_mtu,
        .destroy        = vrf_dst_destroy,
        .default_advmss = vrf_default_advmss,
};

static int init_dst_ops6_kmem_cachep(void)
{
        vrf_dst_ops6.kmem_cachep = kmem_cache_create("vrf_ip6_dst_cache",
                                                     sizeof(struct rt6_info),
                                                     0,
                                                     SLAB_HWCACHE_ALIGN,
                                                     NULL);

        if (!vrf_dst_ops6.kmem_cachep)
                return -ENOMEM;

        return 0;
}

static void free_dst_ops6_kmem_cachep(void)
{
        kmem_cache_destroy(vrf_dst_ops6.kmem_cachep);
}

static int vrf_input6(struct sk_buff *skb)
{
        skb->dev->stats.rx_errors++;
        kfree_skb(skb);
        return 0;
}

/* modelled after ip6_finish_output2 */
static int vrf_finish_output6(struct net *net, struct sock *sk,
                              struct sk_buff *skb)
{
        struct dst_entry *dst = skb_dst(skb);
        struct net_device *dev = dst->dev;
        struct neighbour *neigh;
        struct in6_addr *nexthop;
        int ret;

        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)) {
                ret = dst_neigh_output(dst, neigh, skb);
                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));
}

static void vrf_rt6_destroy(struct net_vrf *vrf)
{
        dst_destroy(&vrf->rt6->dst);
        free_percpu(vrf->rt6->rt6i_pcpu);
        vrf->rt6 = NULL;
}

static int vrf_rt6_create(struct net_device *dev)
{
        struct net_vrf *vrf = netdev_priv(dev);
        struct dst_entry *dst;
        struct rt6_info *rt6;
        int cpu;
        int rc = -ENOMEM;

        rt6 = dst_alloc(&vrf_dst_ops6, dev, 0,
                        DST_OBSOLETE_NONE,
                        (DST_HOST | DST_NOPOLICY | DST_NOXFRM));
        if (!rt6)
                goto out;

        dst = &rt6->dst;

        rt6->rt6i_pcpu = alloc_percpu_gfp(struct rt6_info *, GFP_KERNEL);
        if (!rt6->rt6i_pcpu) {
                dst_destroy(dst);
                goto out;
        }
        for_each_possible_cpu(cpu) {
                struct rt6_info **p = per_cpu_ptr(rt6->rt6i_pcpu, cpu);
                *p =  NULL;
        }

        memset(dst + 1, 0, sizeof(*rt6) - sizeof(*dst));

        INIT_LIST_HEAD(&rt6->rt6i_siblings);
        INIT_LIST_HEAD(&rt6->rt6i_uncached);

        rt6->dst.input  = vrf_input6;
        rt6->dst.output = vrf_output6;

        rt6->rt6i_table = fib6_get_table(dev_net(dev), vrf->tb_id);

        atomic_set(&rt6->dst.__refcnt, 2);

        vrf->rt6 = rt6;
        rc = 0;
out:
        return rc;
}
#else
static int init_dst_ops6_kmem_cachep(void)
{
        return 0;
}

static void free_dst_ops6_kmem_cachep(void)
{
}

static void vrf_rt6_destroy(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;
        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 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));
}

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 net_vrf *vrf = netdev_priv(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;
                rth->rt_table_id = vrf->tb_id;
                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 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)
                goto out_fail;

        slave->dev = port_dev;

        /* 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->priv_flags |= IFF_L3MDEV_SLAVE;
        __vrf_insert_slave(queue, slave);
        cycle_netdev(port_dev);

        return 0;

out_unregister:
        netdev_rx_handler_unregister(port_dev);
out_fail:
        kfree(slave);
        return ret;
}

static int vrf_add_slave(struct net_device *dev, struct net_device *port_dev)
{
        if (netif_is_l3_master(port_dev) || netif_is_l3_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 *vrf = netdev_priv(dev);
        struct slave_queue *queue = &vrf->queue;
        struct slave *slave;

        netdev_upper_dev_unlink(port_dev, dev);
        port_dev->priv_flags &= ~IFF_L3MDEV_SLAVE;

        netdev_rx_handler_unregister(port_dev);

        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);
        vrf_rt6_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;

        if (vrf_rt6_create(dev) != 0)
                goto out_rth;

        dev->flags = IFF_MASTER | IFF_NOARP;

        return 0;

out_rth:
        vrf_rtable_destroy(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_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 struct rtable *vrf_get_rtable(const struct net_device *dev,
                                     const struct flowi4 *fl4)
{
        struct rtable *rth = NULL;

        if (!(fl4->flowi4_flags & FLOWI_FLAG_L3MDEV_SRC)) {
                struct net_vrf *vrf = netdev_priv(dev);

                rth = vrf->rth;
                atomic_inc(&rth->dst.__refcnt);
        }

        return rth;
}

/* called under rcu_read_lock */
static void vrf_get_saddr(struct net_device *dev, struct flowi4 *fl4)
{
        struct fib_result res = { .tclassid = 0 };
        struct net *net = dev_net(dev);
        u32 orig_tos = fl4->flowi4_tos;
        u8 flags = fl4->flowi4_flags;
        u8 scope = fl4->flowi4_scope;
        u8 tos = RT_FL_TOS(fl4);

        if (unlikely(!fl4->daddr))
                return;

        fl4->flowi4_flags |= FLOWI_FLAG_SKIP_NH_OIF;
        fl4->flowi4_iif = LOOPBACK_IFINDEX;
        fl4->flowi4_tos = tos & IPTOS_RT_MASK;
        fl4->flowi4_scope = ((tos & RTO_ONLINK) ?
                             RT_SCOPE_LINK : RT_SCOPE_UNIVERSE);

        if (!fib_lookup(net, fl4, &res, 0)) {
                if (res.type == RTN_LOCAL)
                        fl4->saddr = res.fi->fib_prefsrc ? : fl4->daddr;
                else
                        fib_select_path(net, &res, fl4, -1);
        }

        fl4->flowi4_flags = flags;
        fl4->flowi4_tos = orig_tos;
        fl4->flowi4_scope = scope;
}

#if IS_ENABLED(CONFIG_IPV6)
static struct dst_entry *vrf_get_rt6_dst(const struct net_device *dev,
                                         const struct flowi6 *fl6)
{
        struct rt6_info *rt = NULL;

        if (!(fl6->flowi6_flags & FLOWI_FLAG_L3MDEV_SRC)) {
                struct net_vrf *vrf = netdev_priv(dev);

                rt = vrf->rt6;
                atomic_inc(&rt->dst.__refcnt);
        }

        return (struct dst_entry *)rt;
}
#endif

static const struct l3mdev_ops vrf_l3mdev_ops = {
        .l3mdev_fib_table       = vrf_fib_table,
        .l3mdev_get_rtable      = vrf_get_rtable,
        .l3mdev_get_saddr       = vrf_get_saddr,
#if IS_ENABLED(CONFIG_IPV6)
        .l3mdev_get_rt6_dst     = vrf_get_rt6_dst,
#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 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->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)
{
        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);
        int err;

        if (!data || !data[IFLA_VRF_TABLE])
                return -EINVAL;

        vrf->tb_id = nla_get_u32(data[IFLA_VRF_TABLE]);

        dev->priv_flags |= IFF_L3MDEV_MASTER;

        err = register_netdevice(dev);
        if (err < 0)
                goto out_fail;

        return 0;

out_fail:
        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_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 __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;

        rc = init_dst_ops6_kmem_cachep();
        if (rc != 0)
                goto error2;

        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);
        free_dst_ops6_kmem_cachep();
error2:
        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);
        free_dst_ops6_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);