// SPDX-License-Identifier: GPL-2.0-or-later
/* Copyright (c) 2014 Mahesh Bandewar <maheshb@google.com>
 */

#include <net/flow.h>
#include <net/ip.h>

#include "ipvlan.h"

static u32 ipvlan_jhash_secret __read_mostly;

void ipvlan_init_secret(void)
{
        net_get_random_once(&ipvlan_jhash_secret, sizeof(ipvlan_jhash_secret));
}

void ipvlan_count_rx(const struct ipvl_dev *ipvlan,
                            unsigned int len, bool success, bool mcast)
{
        if (likely(success)) {
                struct ipvl_pcpu_stats *pcptr;

                pcptr = this_cpu_ptr(ipvlan->pcpu_stats);
                u64_stats_update_begin(&pcptr->syncp);
                u64_stats_inc(&pcptr->rx_pkts);
                u64_stats_add(&pcptr->rx_bytes, len);
                if (mcast)
                        u64_stats_inc(&pcptr->rx_mcast);
                u64_stats_update_end(&pcptr->syncp);
        } else {
                this_cpu_inc(ipvlan->pcpu_stats->rx_errs);
        }
}
EXPORT_SYMBOL_GPL(ipvlan_count_rx);

#if IS_ENABLED(CONFIG_IPV6)
static u8 ipvlan_get_v6_hash(const void *iaddr)
{
        const struct in6_addr *ip6_addr = iaddr;

        return __ipv6_addr_jhash(ip6_addr, ipvlan_jhash_secret) &
               IPVLAN_HASH_MASK;
}
#else
static u8 ipvlan_get_v6_hash(const void *iaddr)
{
        return 0;
}
#endif

static u8 ipvlan_get_v4_hash(__be32 addr)
{
        return jhash_1word((__force u32)addr, ipvlan_jhash_secret) &
                           IPVLAN_HASH_MASK;
}

static bool addr_equal(bool is_v6, struct ipvl_addr *addr, const void *iaddr)
{
        if (!is_v6 && addr->atype == IPVL_IPV4) {
                struct in_addr *i4addr = (struct in_addr *)iaddr;

                return addr->ip4addr.s_addr == i4addr->s_addr;
#if IS_ENABLED(CONFIG_IPV6)
        } else if (is_v6 && addr->atype == IPVL_IPV6) {
                struct in6_addr *i6addr = (struct in6_addr *)iaddr;

                return ipv6_addr_equal(&addr->ip6addr, i6addr);
#endif
        }

        return false;
}

#if IS_ENABLED(CONFIG_IPV6)
static struct ipvl_addr *ipvlan_ht_addr_lookup6(const struct ipvl_port *port,
                                                const void *iaddr)
{
        struct ipvl_addr *addr;
        u8 hash;

        hash = ipvlan_get_v6_hash(iaddr);
        hlist_for_each_entry_rcu(addr, &port->hlhead[hash], hlnode)
                if (addr_equal(true, addr, iaddr))
                        return addr;
        return NULL;
}
#endif

static struct ipvl_addr *ipvlan_ht_addr_lookup4(const struct ipvl_port *port,
                                                __be32 addr4)
{
        struct ipvl_addr *addr;
        u8 hash;

        hash = ipvlan_get_v4_hash(addr4);
        hlist_for_each_entry_rcu(addr, &port->hlhead[hash], hlnode)
                if (addr->atype == IPVL_IPV4 && addr->ip4addr.s_addr == addr4)
                        return addr;
        return NULL;
}

void ipvlan_ht_addr_add(struct ipvl_dev *ipvlan, struct ipvl_addr *addr)
{
        struct ipvl_port *port = ipvlan->port;
        u8 hash;

        hash = (addr->atype == IPVL_IPV6) ?
               ipvlan_get_v6_hash(&addr->ip6addr) :
               ipvlan_get_v4_hash(addr->ip4addr.s_addr);
        if (hlist_unhashed(&addr->hlnode))
                hlist_add_head_rcu(&addr->hlnode, &port->hlhead[hash]);
}

void ipvlan_ht_addr_del(struct ipvl_addr *addr)
{
        hlist_del_init_rcu(&addr->hlnode);
}

struct ipvl_addr *ipvlan_find_addr(const struct ipvl_dev *ipvlan,
                                   const void *iaddr, bool is_v6)
{
        struct ipvl_addr *addr;

        assert_spin_locked(&ipvlan->port->addrs_lock);

        list_for_each_entry(addr, &ipvlan->addrs, anode) {
                if (addr_equal(is_v6, addr, iaddr))
                        return addr;
        }
        return NULL;
}

bool ipvlan_addr_busy(struct ipvl_port *port, void *iaddr, bool is_v6)
{
        struct ipvl_dev *ipvlan;
        bool ret = false;

        rcu_read_lock();
        list_for_each_entry_rcu(ipvlan, &port->ipvlans, pnode) {
                if (ipvlan_find_addr(ipvlan, iaddr, is_v6)) {
                        ret = true;
                        break;
                }
        }
        rcu_read_unlock();
        return ret;
}

void *ipvlan_get_L3_hdr(struct ipvl_port *port, struct sk_buff *skb, int *type)
{
        void *lyr3h = NULL;

        switch (skb->protocol) {
        case htons(ETH_P_ARP): {
                struct arphdr *arph;

                if (unlikely(!pskb_may_pull(skb, arp_hdr_len(port->dev))))
                        return NULL;

                arph = arp_hdr(skb);
                *type = IPVL_ARP;
                lyr3h = arph;
                break;
        }
        case htons(ETH_P_IP): {
                u32 pktlen;
                struct iphdr *ip4h;

                if (unlikely(!pskb_may_pull(skb, sizeof(*ip4h))))
                        return NULL;

                ip4h = ip_hdr(skb);
                pktlen = skb_ip_totlen(skb);
                if (ip4h->ihl < 5 || ip4h->version != 4)
                        return NULL;
                if (skb->len < pktlen || pktlen < (ip4h->ihl * 4))
                        return NULL;

                *type = IPVL_IPV4;
                lyr3h = ip4h;
                break;
        }
#if IS_ENABLED(CONFIG_IPV6)
        case htons(ETH_P_IPV6): {
                struct ipv6hdr *ip6h;

                if (unlikely(!pskb_may_pull(skb, sizeof(*ip6h))))
                        return NULL;

                ip6h = ipv6_hdr(skb);
                if (ip6h->version != 6)
                        return NULL;

                *type = IPVL_IPV6;
                lyr3h = ip6h;
                /* Only Neighbour Solicitation pkts need different treatment */
                if (ipv6_addr_any(&ip6h->saddr) &&
                    ip6h->nexthdr == NEXTHDR_ICMP) {
                        struct icmp6hdr *icmph;

                        if (unlikely(!pskb_may_pull(skb, sizeof(*ip6h) + sizeof(*icmph))))
                                return NULL;

                        ip6h = ipv6_hdr(skb);
                        icmph = (struct icmp6hdr *)(ip6h + 1);

                        if (icmph->icmp6_type == NDISC_NEIGHBOUR_SOLICITATION) {
                                /* Need to access the ipv6 address in body */
                                if (unlikely(!pskb_may_pull(skb, sizeof(*ip6h) + sizeof(*icmph)
                                                + sizeof(struct in6_addr))))
                                        return NULL;

                                ip6h = ipv6_hdr(skb);
                                icmph = (struct icmp6hdr *)(ip6h + 1);
                        }

                        *type = IPVL_ICMPV6;
                        lyr3h = icmph;
                }
                break;
        }
#endif
        default:
                return NULL;
        }

        return lyr3h;
}

unsigned int ipvlan_mac_hash(const unsigned char *addr)
{
        u32 hash = jhash_1word(get_unaligned((u32 *)(addr + 2)),
                               ipvlan_jhash_secret);

        return hash & IPVLAN_MAC_FILTER_MASK;
}

void ipvlan_process_multicast(struct work_struct *work)
{
        struct ipvl_port *port = container_of(work, struct ipvl_port, wq);
        struct ethhdr *ethh;
        struct ipvl_dev *ipvlan;
        struct sk_buff *skb, *nskb;
        struct sk_buff_head list;
        unsigned int len;
        unsigned int mac_hash;
        int ret;
        u8 pkt_type;
        bool tx_pkt;

        __skb_queue_head_init(&list);

        spin_lock_bh(&port->backlog.lock);
        skb_queue_splice_tail_init(&port->backlog, &list);
        spin_unlock_bh(&port->backlog.lock);

        while ((skb = __skb_dequeue(&list)) != NULL) {
                struct net_device *dev = skb->dev;
                bool consumed = false;

                ethh = eth_hdr(skb);
                tx_pkt = IPVL_SKB_CB(skb)->tx_pkt;
                mac_hash = ipvlan_mac_hash(ethh->h_dest);

                if (ether_addr_equal(ethh->h_dest, port->dev->broadcast))
                        pkt_type = PACKET_BROADCAST;
                else
                        pkt_type = PACKET_MULTICAST;

                rcu_read_lock();
                list_for_each_entry_rcu(ipvlan, &port->ipvlans, pnode) {
                        if (tx_pkt && (ipvlan->dev == skb->dev))
                                continue;
                        if (!test_bit(mac_hash, ipvlan->mac_filters))
                                continue;
                        if (!(ipvlan->dev->flags & IFF_UP))
                                continue;
                        ret = NET_RX_DROP;
                        len = skb->len + ETH_HLEN;
                        nskb = skb_clone(skb, GFP_ATOMIC);
                        local_bh_disable();
                        if (nskb) {
                                consumed = true;
                                nskb->pkt_type = pkt_type;
                                nskb->dev = ipvlan->dev;
                                if (tx_pkt)
                                        ret = dev_forward_skb(ipvlan->dev, nskb);
                                else
                                        ret = netif_rx(nskb);
                        }
                        ipvlan_count_rx(ipvlan, len, ret == NET_RX_SUCCESS, true);
                        local_bh_enable();
                }
                rcu_read_unlock();

                if (tx_pkt) {
                        /* If the packet originated here, send it out. */
                        skb->dev = port->dev;
                        skb->pkt_type = pkt_type;
                        dev_queue_xmit(skb);
                } else {
                        if (consumed)
                                consume_skb(skb);
                        else
                                kfree_skb(skb);
                }
                dev_put(dev);
                cond_resched();
        }
}

static void ipvlan_skb_crossing_ns(struct sk_buff *skb, struct net_device *dev)
{
        bool xnet = true;

        if (dev)
                xnet = !net_eq(dev_net(skb->dev), dev_net(dev));

        skb_scrub_packet(skb, xnet);
        if (dev)
                skb->dev = dev;
}

static int ipvlan_rcv_frame(struct ipvl_addr *addr, struct sk_buff **pskb,
                            bool local)
{
        struct ipvl_dev *ipvlan = addr->master;
        struct net_device *dev = ipvlan->dev;
        unsigned int len;
        rx_handler_result_t ret = RX_HANDLER_CONSUMED;
        bool success = false;
        struct sk_buff *skb = *pskb;

        len = skb->len + ETH_HLEN;
        /* Only packets exchanged between two local slaves need to have
         * device-up check as well as skb-share check.
         */
        if (local) {
                if (unlikely(!(dev->flags & IFF_UP))) {
                        kfree_skb(skb);
                        goto out;
                }

                skb = skb_share_check(skb, GFP_ATOMIC);
                if (!skb)
                        goto out;

                *pskb = skb;
        }

        if (local) {
                skb->pkt_type = PACKET_HOST;
                if (dev_forward_skb(ipvlan->dev, skb) == NET_RX_SUCCESS)
                        success = true;
        } else {
                skb->dev = dev;
                ret = RX_HANDLER_ANOTHER;
                success = true;
        }

out:
        ipvlan_count_rx(ipvlan, len, success, false);
        return ret;
}

struct ipvl_addr *ipvlan_addr_lookup(struct ipvl_port *port, void *lyr3h,
                                     int addr_type, bool use_dest)
{
        struct ipvl_addr *addr = NULL;
#if IS_ENABLED(CONFIG_IPV6)
        struct in6_addr *i6addr;
#endif
        __be32 addr4;

        switch (addr_type) {
#if IS_ENABLED(CONFIG_IPV6)
        case IPVL_IPV6: {
                struct ipv6hdr *ip6h;

                ip6h = (struct ipv6hdr *)lyr3h;
                i6addr = use_dest ? &ip6h->daddr : &ip6h->saddr;
lookup6:
                addr = ipvlan_ht_addr_lookup6(port, i6addr);
                break;
        }
        case IPVL_ICMPV6: {
                struct nd_msg *ndmh;

                /* Make sure that the NeighborSolicitation ICMPv6 packets
                 * are handled to avoid DAD issue.
                 */
                ndmh = (struct nd_msg *)lyr3h;
                if (ndmh->icmph.icmp6_type == NDISC_NEIGHBOUR_SOLICITATION) {
                        i6addr = &ndmh->target;
                        goto lookup6;
                }
                break;
        }
#endif
        case IPVL_IPV4: {
                struct iphdr *ip4h;

                ip4h = (struct iphdr *)lyr3h;
                addr4 = use_dest ? ip4h->daddr : ip4h->saddr;
lookup4:
                addr = ipvlan_ht_addr_lookup4(port, addr4);
                break;
        }
        case IPVL_ARP: {
                struct arphdr *arph;
                unsigned char *arp_ptr;

                arph = (struct arphdr *)lyr3h;
                arp_ptr = (unsigned char *)(arph + 1);
                if (use_dest)
                        arp_ptr += (2 * port->dev->addr_len) + 4;
                else
                        arp_ptr += port->dev->addr_len;

                addr4 = get_unaligned((__be32 *)arp_ptr);
                goto lookup4;
        }
        }

        return addr;
}

static noinline_for_stack int ipvlan_process_v4_outbound(struct sk_buff *skb)
{
        struct net_device *dev = skb->dev;
        struct net *net = dev_net(dev);
        int err, ret = NET_XMIT_DROP;
        const struct iphdr *ip4h;
        struct rtable *rt;
        struct flowi4 fl4 = {
                .flowi4_oif = dev->ifindex,
                .flowi4_flags = FLOWI_FLAG_ANYSRC,
                .flowi4_mark = skb->mark,
        };

        if (!pskb_network_may_pull(skb, sizeof(struct iphdr)))
                goto err;

        ip4h = ip_hdr(skb);
        fl4.daddr = ip4h->daddr;
        fl4.saddr = ip4h->saddr;
        fl4.flowi4_dscp = ip4h_dscp(ip4h);

        rt = ip_route_output_flow(net, &fl4, NULL);
        if (IS_ERR(rt))
                goto err;

        if (rt->rt_type != RTN_UNICAST && rt->rt_type != RTN_LOCAL) {
                ip_rt_put(rt);
                goto err;
        }
        skb_dst_set(skb, &rt->dst);

        memset(IPCB(skb), 0, sizeof(*IPCB(skb)));

        err = ip_local_out(net, NULL, skb);
        if (unlikely(net_xmit_eval(err)))
                DEV_STATS_INC(dev, tx_errors);
        else
                ret = NET_XMIT_SUCCESS;
        goto out;
err:
        DEV_STATS_INC(dev, tx_errors);
        kfree_skb(skb);
out:
        return ret;
}

#if IS_ENABLED(CONFIG_IPV6)

static noinline_for_stack int
ipvlan_route_v6_outbound(struct net_device *dev, struct sk_buff *skb)
{
        const struct ipv6hdr *ip6h = ipv6_hdr(skb);
        struct flowi6 fl6 = {
                .flowi6_oif = dev->ifindex,
                .daddr = ip6h->daddr,
                .saddr = ip6h->saddr,
                .flowi6_flags = FLOWI_FLAG_ANYSRC,
                .flowlabel = ip6_flowinfo(ip6h),
                .flowi6_mark = skb->mark,
                .flowi6_proto = ip6h->nexthdr,
        };
        struct dst_entry *dst;
        int err;

        dst = ip6_route_output(dev_net(dev), NULL, &fl6);
        err = dst->error;
        if (err) {
                dst_release(dst);
                return err;
        }
        skb_dst_set(skb, dst);
        return 0;
}

static int ipvlan_process_v6_outbound(struct sk_buff *skb)
{
        struct net_device *dev = skb->dev;
        int err, ret = NET_XMIT_DROP;

        if (!pskb_network_may_pull(skb, sizeof(struct ipv6hdr))) {
                DEV_STATS_INC(dev, tx_errors);
                kfree_skb(skb);
                return ret;
        }

        err = ipvlan_route_v6_outbound(dev, skb);
        if (unlikely(err)) {
                DEV_STATS_INC(dev, tx_errors);
                kfree_skb(skb);
                return err;
        }

        memset(IP6CB(skb), 0, sizeof(*IP6CB(skb)));

        err = ip6_local_out(dev_net(dev), NULL, skb);
        if (unlikely(net_xmit_eval(err)))
                DEV_STATS_INC(dev, tx_errors);
        else
                ret = NET_XMIT_SUCCESS;
        return ret;
}
#else
static int ipvlan_process_v6_outbound(struct sk_buff *skb)
{
        return NET_XMIT_DROP;
}
#endif

static int ipvlan_process_outbound(struct sk_buff *skb)
{
        int ret = NET_XMIT_DROP;

        /* The ipvlan is a pseudo-L2 device, so the packets that we receive
         * will have L2; which need to discarded and processed further
         * in the net-ns of the main-device.
         */
        if (skb_mac_header_was_set(skb)) {
                /* In this mode we dont care about
                 * multicast and broadcast traffic */
                struct ethhdr *ethh = eth_hdr(skb);

                if (is_multicast_ether_addr(ethh->h_dest)) {
                        pr_debug_ratelimited(
                                "Dropped {multi|broad}cast of type=[%x]\n",
                                ntohs(skb->protocol));
                        kfree_skb(skb);
                        goto out;
                }

                skb_pull(skb, sizeof(*ethh));
                skb->mac_header = (typeof(skb->mac_header))~0U;
                skb_reset_network_header(skb);
        }

        if (skb->protocol == htons(ETH_P_IPV6))
                ret = ipvlan_process_v6_outbound(skb);
        else if (skb->protocol == htons(ETH_P_IP))
                ret = ipvlan_process_v4_outbound(skb);
        else {
                pr_warn_ratelimited("Dropped outbound packet type=%x\n",
                                    ntohs(skb->protocol));
                kfree_skb(skb);
        }
out:
        return ret;
}

static void ipvlan_multicast_enqueue(struct ipvl_port *port,
                                     struct sk_buff *skb, bool tx_pkt)
{
        if (skb->protocol == htons(ETH_P_PAUSE)) {
                kfree_skb(skb);
                return;
        }

        /* Record that the deferred packet is from TX or RX path. By
         * looking at mac-addresses on packet will lead to erronus decisions.
         * (This would be true for a loopback-mode on master device or a
         * hair-pin mode of the switch.)
         */
        IPVL_SKB_CB(skb)->tx_pkt = tx_pkt;

        spin_lock(&port->backlog.lock);
        if (skb_queue_len(&port->backlog) < IPVLAN_QBACKLOG_LIMIT) {
                dev_hold(skb->dev);
                __skb_queue_tail(&port->backlog, skb);
                spin_unlock(&port->backlog.lock);
                schedule_work(&port->wq);
        } else {
                spin_unlock(&port->backlog.lock);
                dev_core_stats_rx_dropped_inc(skb->dev);
                kfree_skb(skb);
        }
}

static int ipvlan_xmit_mode_l3(struct sk_buff *skb, struct net_device *dev)
{
        const struct ipvl_dev *ipvlan = netdev_priv(dev);
        void *lyr3h;
        struct ipvl_addr *addr;
        int addr_type;

        lyr3h = ipvlan_get_L3_hdr(ipvlan->port, skb, &addr_type);
        if (!lyr3h)
                goto out;

        if (!ipvlan_is_vepa(ipvlan->port)) {
                addr = ipvlan_addr_lookup(ipvlan->port, lyr3h, addr_type, true);
                if (addr) {
                        if (ipvlan_is_private(ipvlan->port)) {
                                consume_skb(skb);
                                return NET_XMIT_DROP;
                        }
                        ipvlan_rcv_frame(addr, &skb, true);
                        return NET_XMIT_SUCCESS;
                }
        }
out:
        ipvlan_skb_crossing_ns(skb, ipvlan->phy_dev);
        return ipvlan_process_outbound(skb);
}

static int ipvlan_xmit_mode_l2(struct sk_buff *skb, struct net_device *dev)
{
        const struct ipvl_dev *ipvlan = netdev_priv(dev);
        struct ethhdr *eth = skb_eth_hdr(skb);
        struct ipvl_addr *addr;
        void *lyr3h;
        int addr_type;

        if (!ipvlan_is_vepa(ipvlan->port) &&
            ether_addr_equal(eth->h_dest, eth->h_source)) {
                lyr3h = ipvlan_get_L3_hdr(ipvlan->port, skb, &addr_type);
                if (lyr3h) {
                        addr = ipvlan_addr_lookup(ipvlan->port, lyr3h, addr_type, true);
                        if (addr) {
                                if (ipvlan_is_private(ipvlan->port)) {
                                        consume_skb(skb);
                                        return NET_XMIT_DROP;
                                }
                                ipvlan_rcv_frame(addr, &skb, true);
                                return NET_XMIT_SUCCESS;
                        }
                }
                skb = skb_share_check(skb, GFP_ATOMIC);
                if (!skb)
                        return NET_XMIT_DROP;

                /* Packet definitely does not belong to any of the
                 * virtual devices, but the dest is local. So forward
                 * the skb for the main-dev. At the RX side we just return
                 * RX_PASS for it to be processed further on the stack.
                 */
                dev_forward_skb(ipvlan->phy_dev, skb);
                return NET_XMIT_SUCCESS;

        } else if (is_multicast_ether_addr(eth->h_dest)) {
                skb_reset_mac_header(skb);
                ipvlan_skb_crossing_ns(skb, NULL);
                ipvlan_multicast_enqueue(ipvlan->port, skb, true);
                return NET_XMIT_SUCCESS;
        }

        skb->dev = ipvlan->phy_dev;
        return dev_queue_xmit(skb);
}

int ipvlan_queue_xmit(struct sk_buff *skb, struct net_device *dev)
{
        struct ipvl_dev *ipvlan = netdev_priv(dev);
        struct ipvl_port *port = ipvlan_port_get_rcu_bh(ipvlan->phy_dev);

        if (!port)
                goto out;

        if (unlikely(!pskb_may_pull(skb, sizeof(struct ethhdr))))
                goto out;

        switch(port->mode) {
        case IPVLAN_MODE_L2:
                return ipvlan_xmit_mode_l2(skb, dev);
        case IPVLAN_MODE_L3:
#ifdef CONFIG_IPVLAN_L3S
        case IPVLAN_MODE_L3S:
#endif
                return ipvlan_xmit_mode_l3(skb, dev);
        }

        /* Should not reach here */
        WARN_ONCE(true, "%s called for mode = [%x]\n", __func__, port->mode);
out:
        kfree_skb(skb);
        return NET_XMIT_DROP;
}

static bool ipvlan_external_frame(struct sk_buff *skb, struct ipvl_port *port)
{
        struct ethhdr *eth = eth_hdr(skb);
        struct ipvl_addr *addr;
        void *lyr3h;
        int addr_type;

        if (ether_addr_equal(eth->h_source, skb->dev->dev_addr)) {
                lyr3h = ipvlan_get_L3_hdr(port, skb, &addr_type);
                if (!lyr3h)
                        return true;

                addr = ipvlan_addr_lookup(port, lyr3h, addr_type, false);
                if (addr)
                        return false;
        }

        return true;
}

static rx_handler_result_t ipvlan_handle_mode_l3(struct sk_buff **pskb,
                                                 struct ipvl_port *port)
{
        void *lyr3h;
        int addr_type;
        struct ipvl_addr *addr;
        struct sk_buff *skb = *pskb;
        rx_handler_result_t ret = RX_HANDLER_PASS;

        lyr3h = ipvlan_get_L3_hdr(port, skb, &addr_type);
        if (!lyr3h)
                goto out;

        addr = ipvlan_addr_lookup(port, lyr3h, addr_type, true);
        if (addr)
                ret = ipvlan_rcv_frame(addr, pskb, false);

out:
        return ret;
}

static rx_handler_result_t ipvlan_handle_mode_l2(struct sk_buff **pskb,
                                                 struct ipvl_port *port)
{
        struct sk_buff *skb = *pskb;
        struct ethhdr *eth = eth_hdr(skb);
        rx_handler_result_t ret = RX_HANDLER_PASS;

        if (unlikely(skb->pkt_type == PACKET_LOOPBACK))
                return RX_HANDLER_PASS;

        if (is_multicast_ether_addr(eth->h_dest)) {
                if (ipvlan_external_frame(skb, port)) {
                        struct sk_buff *nskb = skb_clone(skb, GFP_ATOMIC);

                        /* External frames are queued for device local
                         * distribution, but a copy is given to master
                         * straight away to avoid sending duplicates later
                         * when work-queue processes this frame. This is
                         * achieved by returning RX_HANDLER_PASS.
                         */
                        if (nskb) {
                                ipvlan_skb_crossing_ns(nskb, NULL);
                                ipvlan_multicast_enqueue(port, nskb, false);
                        }
                }
        } else {
                /* Perform like l3 mode for non-multicast packet */
                ret = ipvlan_handle_mode_l3(pskb, port);
        }

        return ret;
}

rx_handler_result_t ipvlan_handle_frame(struct sk_buff **pskb)
{
        struct sk_buff *skb = *pskb;
        struct ipvl_port *port = ipvlan_port_get_rcu(skb->dev);

        if (!port)
                return RX_HANDLER_PASS;

        switch (port->mode) {
        case IPVLAN_MODE_L2:
                return ipvlan_handle_mode_l2(pskb, port);
        case IPVLAN_MODE_L3:
                return ipvlan_handle_mode_l3(pskb, port);
#ifdef CONFIG_IPVLAN_L3S
        case IPVLAN_MODE_L3S:
                return RX_HANDLER_PASS;
#endif
        }

        /* Should not reach here */
        WARN_ONCE(true, "%s called for mode = [%x]\n", __func__, port->mode);
        kfree_skb(skb);
        return RX_HANDLER_CONSUMED;
}