root/drivers/net/bareudp.c
// SPDX-License-Identifier: GPL-2.0
/* Bareudp: UDP  tunnel encasulation for different Payload types like
 * MPLS, NSH, IP, etc.
 * Copyright (c) 2019 Nokia, Inc.
 * Authors:  Martin Varghese, <martin.varghese@nokia.com>
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/etherdevice.h>
#include <linux/hash.h>
#include <net/dst_metadata.h>
#include <net/gro_cells.h>
#include <net/rtnetlink.h>
#include <net/protocol.h>
#include <net/ip6_tunnel.h>
#include <net/ip_tunnels.h>
#include <net/udp_tunnel.h>
#include <net/bareudp.h>

#define BAREUDP_BASE_HLEN sizeof(struct udphdr)
#define BAREUDP_IPV4_HLEN (sizeof(struct iphdr) + \
                           sizeof(struct udphdr))
#define BAREUDP_IPV6_HLEN (sizeof(struct ipv6hdr) + \
                           sizeof(struct udphdr))

static bool log_ecn_error = true;
module_param(log_ecn_error, bool, 0644);
MODULE_PARM_DESC(log_ecn_error, "Log packets received with corrupted ECN");

/* per-network namespace private data for this module */

static unsigned int bareudp_net_id;

struct bareudp_net {
        struct list_head        bareudp_list;
};

struct bareudp_conf {
        __be16 ethertype;
        __be16 port;
        u16 sport_min;
        bool multi_proto_mode;
};

/* Pseudo network device */
struct bareudp_dev {
        struct net         *net;        /* netns for packet i/o */
        struct net_device  *dev;        /* netdev for bareudp tunnel */
        __be16             ethertype;
        __be16             port;
        u16                sport_min;
        bool               multi_proto_mode;
        struct socket      __rcu *sock;
        struct list_head   next;        /* bareudp node  on namespace list */
        struct gro_cells   gro_cells;
};

static int bareudp_udp_encap_recv(struct sock *sk, struct sk_buff *skb)
{
        struct metadata_dst *tun_dst = NULL;
        IP_TUNNEL_DECLARE_FLAGS(key) = { };
        struct bareudp_dev *bareudp;
        unsigned short family;
        unsigned int len;
        __be16 proto;
        void *oiph;
        int err;
        int nh;

        bareudp = rcu_dereference_sk_user_data(sk);
        if (!bareudp)
                goto drop;

        if (skb->protocol ==  htons(ETH_P_IP))
                family = AF_INET;
        else
                family = AF_INET6;

        if (bareudp->ethertype == htons(ETH_P_IP)) {
                __u8 ipversion;

                if (skb_copy_bits(skb, BAREUDP_BASE_HLEN, &ipversion,
                                  sizeof(ipversion))) {
                        dev_dstats_rx_dropped(bareudp->dev);
                        goto drop;
                }
                ipversion >>= 4;

                if (ipversion == 4) {
                        proto = htons(ETH_P_IP);
                } else if (ipversion == 6 && bareudp->multi_proto_mode) {
                        proto = htons(ETH_P_IPV6);
                } else {
                        dev_dstats_rx_dropped(bareudp->dev);
                        goto drop;
                }
        } else if (bareudp->ethertype == htons(ETH_P_MPLS_UC)) {
                struct iphdr *tunnel_hdr;

                tunnel_hdr = (struct iphdr *)skb_network_header(skb);
                if (tunnel_hdr->version == 4) {
                        if (!ipv4_is_multicast(tunnel_hdr->daddr)) {
                                proto = bareudp->ethertype;
                        } else if (bareudp->multi_proto_mode &&
                                   ipv4_is_multicast(tunnel_hdr->daddr)) {
                                proto = htons(ETH_P_MPLS_MC);
                        } else {
                                dev_dstats_rx_dropped(bareudp->dev);
                                goto drop;
                        }
                } else {
                        int addr_type;
                        struct ipv6hdr *tunnel_hdr_v6;

                        tunnel_hdr_v6 = (struct ipv6hdr *)skb_network_header(skb);
                        addr_type =
                        ipv6_addr_type((struct in6_addr *)&tunnel_hdr_v6->daddr);
                        if (!(addr_type & IPV6_ADDR_MULTICAST)) {
                                proto = bareudp->ethertype;
                        } else if (bareudp->multi_proto_mode &&
                                   (addr_type & IPV6_ADDR_MULTICAST)) {
                                proto = htons(ETH_P_MPLS_MC);
                        } else {
                                dev_dstats_rx_dropped(bareudp->dev);
                                goto drop;
                        }
                }
        } else {
                proto = bareudp->ethertype;
        }

        if (iptunnel_pull_header(skb, BAREUDP_BASE_HLEN,
                                 proto,
                                 !net_eq(bareudp->net,
                                 dev_net(bareudp->dev)))) {
                dev_dstats_rx_dropped(bareudp->dev);
                goto drop;
        }

        __set_bit(IP_TUNNEL_KEY_BIT, key);

        tun_dst = udp_tun_rx_dst(skb, family, key, 0, 0);
        if (!tun_dst) {
                dev_dstats_rx_dropped(bareudp->dev);
                goto drop;
        }
        skb_dst_set(skb, &tun_dst->dst);
        skb->dev = bareudp->dev;
        skb_reset_mac_header(skb);

        /* Save offset of outer header relative to skb->head,
         * because we are going to reset the network header to the inner header
         * and might change skb->head.
         */
        nh = skb_network_header(skb) - skb->head;

        skb_reset_network_header(skb);

        if (!pskb_inet_may_pull(skb)) {
                DEV_STATS_INC(bareudp->dev, rx_length_errors);
                DEV_STATS_INC(bareudp->dev, rx_errors);
                goto drop;
        }

        /* Get the outer header. */
        oiph = skb->head + nh;

        if (!ipv6_mod_enabled() || family == AF_INET)
                err = IP_ECN_decapsulate(oiph, skb);
        else
                err = IP6_ECN_decapsulate(oiph, skb);

        if (unlikely(err)) {
                if (log_ecn_error) {
                        if  (!ipv6_mod_enabled() || family == AF_INET)
                                net_info_ratelimited("non-ECT from %pI4 "
                                                     "with TOS=%#x\n",
                                                     &((struct iphdr *)oiph)->saddr,
                                                     ((struct iphdr *)oiph)->tos);
                        else
                                net_info_ratelimited("non-ECT from %pI6\n",
                                                     &((struct ipv6hdr *)oiph)->saddr);
                }
                if (err > 1) {
                        DEV_STATS_INC(bareudp->dev, rx_frame_errors);
                        DEV_STATS_INC(bareudp->dev, rx_errors);
                        goto drop;
                }
        }

        len = skb->len;
        err = gro_cells_receive(&bareudp->gro_cells, skb);
        if (likely(err == NET_RX_SUCCESS))
                dev_dstats_rx_add(bareudp->dev, len);

        return 0;
drop:
        /* Consume bad packet */
        kfree_skb(skb);

        return 0;
}

static int bareudp_err_lookup(struct sock *sk, struct sk_buff *skb)
{
        return 0;
}

static int bareudp_init(struct net_device *dev)
{
        struct bareudp_dev *bareudp = netdev_priv(dev);
        int err;

        err = gro_cells_init(&bareudp->gro_cells, dev);
        if (err)
                return err;

        return 0;
}

static void bareudp_uninit(struct net_device *dev)
{
        struct bareudp_dev *bareudp = netdev_priv(dev);

        gro_cells_destroy(&bareudp->gro_cells);
}

static struct socket *bareudp_create_sock(struct net *net, __be16 port)
{
        struct udp_port_cfg udp_conf;
        struct socket *sock;
        int err;

        memset(&udp_conf, 0, sizeof(udp_conf));

        if (ipv6_mod_enabled())
                udp_conf.family = AF_INET6;
        else
                udp_conf.family = AF_INET;

        udp_conf.local_udp_port = port;
        /* Open UDP socket */
        err = udp_sock_create(net, &udp_conf, &sock);
        if (err < 0)
                return ERR_PTR(err);

        udp_allow_gso(sock->sk);
        return sock;
}

/* Create new listen socket if needed */
static int bareudp_socket_create(struct bareudp_dev *bareudp, __be16 port)
{
        struct udp_tunnel_sock_cfg tunnel_cfg;
        struct socket *sock;

        sock = bareudp_create_sock(bareudp->net, port);
        if (IS_ERR(sock))
                return PTR_ERR(sock);

        /* Mark socket as an encapsulation socket */
        memset(&tunnel_cfg, 0, sizeof(tunnel_cfg));
        tunnel_cfg.sk_user_data = bareudp;
        tunnel_cfg.encap_type = 1;
        tunnel_cfg.encap_rcv = bareudp_udp_encap_recv;
        tunnel_cfg.encap_err_lookup = bareudp_err_lookup;
        tunnel_cfg.encap_destroy = NULL;
        setup_udp_tunnel_sock(bareudp->net, sock, &tunnel_cfg);

        rcu_assign_pointer(bareudp->sock, sock);
        return 0;
}

static int bareudp_open(struct net_device *dev)
{
        struct bareudp_dev *bareudp = netdev_priv(dev);
        int ret = 0;

        ret =  bareudp_socket_create(bareudp, bareudp->port);
        return ret;
}

static void bareudp_sock_release(struct bareudp_dev *bareudp)
{
        struct socket *sock;

        sock = bareudp->sock;
        rcu_assign_pointer(bareudp->sock, NULL);
        synchronize_net();
        udp_tunnel_sock_release(sock);
}

static int bareudp_stop(struct net_device *dev)
{
        struct bareudp_dev *bareudp = netdev_priv(dev);

        bareudp_sock_release(bareudp);
        return 0;
}

static int bareudp_xmit_skb(struct sk_buff *skb, struct net_device *dev,
                            struct bareudp_dev *bareudp,
                            const struct ip_tunnel_info *info)
{
        bool udp_sum = test_bit(IP_TUNNEL_CSUM_BIT, info->key.tun_flags);
        bool xnet = !net_eq(bareudp->net, dev_net(bareudp->dev));
        bool use_cache = ip_tunnel_dst_cache_usable(skb, info);
        struct socket *sock = rcu_dereference(bareudp->sock);
        const struct ip_tunnel_key *key = &info->key;
        struct rtable *rt;
        __be16 sport, df;
        int min_headroom;
        __u8 tos, ttl;
        __be32 saddr;
        int err;

        if (skb_vlan_inet_prepare(skb, skb->protocol != htons(ETH_P_TEB)))
                return -EINVAL;

        if (!sock)
                return -ESHUTDOWN;

        sport = udp_flow_src_port(bareudp->net, skb,
                                  bareudp->sport_min, USHRT_MAX,
                                  true);
        rt = udp_tunnel_dst_lookup(skb, dev, bareudp->net, 0, &saddr, &info->key,
                                   sport, bareudp->port, key->tos,
                                   use_cache ?
                                   (struct dst_cache *)&info->dst_cache : NULL);

        if (IS_ERR(rt))
                return PTR_ERR(rt);

        skb_tunnel_check_pmtu(skb, &rt->dst,
                              BAREUDP_IPV4_HLEN + info->options_len, false);

        tos = ip_tunnel_ecn_encap(key->tos, ip_hdr(skb), skb);
        ttl = key->ttl;
        df = test_bit(IP_TUNNEL_DONT_FRAGMENT_BIT, key->tun_flags) ?
             htons(IP_DF) : 0;
        skb_scrub_packet(skb, xnet);

        err = -ENOSPC;
        if (!skb_pull(skb, skb_network_offset(skb)))
                goto free_dst;

        min_headroom = LL_RESERVED_SPACE(rt->dst.dev) + rt->dst.header_len +
                BAREUDP_BASE_HLEN + info->options_len + sizeof(struct iphdr);

        err = skb_cow_head(skb, min_headroom);
        if (unlikely(err))
                goto free_dst;

        err = udp_tunnel_handle_offloads(skb, udp_sum);
        if (err)
                goto free_dst;

        skb_set_inner_protocol(skb, bareudp->ethertype);
        udp_tunnel_xmit_skb(rt, sock->sk, skb, saddr, info->key.u.ipv4.dst,
                            tos, ttl, df, sport, bareudp->port,
                            !net_eq(bareudp->net, dev_net(bareudp->dev)),
                            !test_bit(IP_TUNNEL_CSUM_BIT, info->key.tun_flags),
                            0);
        return 0;

free_dst:
        dst_release(&rt->dst);
        return err;
}

static int bareudp6_xmit_skb(struct sk_buff *skb, struct net_device *dev,
                             struct bareudp_dev *bareudp,
                             const struct ip_tunnel_info *info)
{
        bool udp_sum = test_bit(IP_TUNNEL_CSUM_BIT, info->key.tun_flags);
        bool xnet = !net_eq(bareudp->net, dev_net(bareudp->dev));
        bool use_cache = ip_tunnel_dst_cache_usable(skb, info);
        struct socket *sock  = rcu_dereference(bareudp->sock);
        const struct ip_tunnel_key *key = &info->key;
        struct dst_entry *dst = NULL;
        struct in6_addr saddr, daddr;
        int min_headroom;
        __u8 prio, ttl;
        __be16 sport;
        int err;

        if (skb_vlan_inet_prepare(skb, skb->protocol != htons(ETH_P_TEB)))
                return -EINVAL;

        if (!sock)
                return -ESHUTDOWN;

        sport = udp_flow_src_port(bareudp->net, skb,
                                  bareudp->sport_min, USHRT_MAX,
                                  true);
        dst = udp_tunnel6_dst_lookup(skb, dev, bareudp->net, sock, 0, &saddr,
                                     key, sport, bareudp->port, key->tos,
                                     use_cache ?
                                     (struct dst_cache *) &info->dst_cache : NULL);
        if (IS_ERR(dst))
                return PTR_ERR(dst);

        skb_tunnel_check_pmtu(skb, dst, BAREUDP_IPV6_HLEN + info->options_len,
                              false);

        prio = ip_tunnel_ecn_encap(key->tos, ip_hdr(skb), skb);
        ttl = key->ttl;

        skb_scrub_packet(skb, xnet);

        err = -ENOSPC;
        if (!skb_pull(skb, skb_network_offset(skb)))
                goto free_dst;

        min_headroom = LL_RESERVED_SPACE(dst->dev) + dst->header_len +
                BAREUDP_BASE_HLEN + info->options_len + sizeof(struct ipv6hdr);

        err = skb_cow_head(skb, min_headroom);
        if (unlikely(err))
                goto free_dst;

        err = udp_tunnel_handle_offloads(skb, udp_sum);
        if (err)
                goto free_dst;

        daddr = info->key.u.ipv6.dst;
        udp_tunnel6_xmit_skb(dst, sock->sk, skb, dev,
                             &saddr, &daddr, prio, ttl,
                             info->key.label, sport, bareudp->port,
                             !test_bit(IP_TUNNEL_CSUM_BIT,
                                       info->key.tun_flags),
                             0);
        return 0;

free_dst:
        dst_release(dst);
        return err;
}

static bool bareudp_proto_valid(struct bareudp_dev *bareudp, __be16 proto)
{
        if (bareudp->ethertype == proto)
                return true;

        if (!bareudp->multi_proto_mode)
                return false;

        if (bareudp->ethertype == htons(ETH_P_MPLS_UC) &&
            proto == htons(ETH_P_MPLS_MC))
                return true;

        if (bareudp->ethertype == htons(ETH_P_IP) &&
            proto == htons(ETH_P_IPV6))
                return true;

        return false;
}

static netdev_tx_t bareudp_xmit(struct sk_buff *skb, struct net_device *dev)
{
        struct bareudp_dev *bareudp = netdev_priv(dev);
        struct ip_tunnel_info *info = NULL;
        int err;

        if (!bareudp_proto_valid(bareudp, skb->protocol)) {
                err = -EINVAL;
                goto tx_error;
        }

        info = skb_tunnel_info(skb);
        if (unlikely(!info || !(info->mode & IP_TUNNEL_INFO_TX))) {
                err = -EINVAL;
                goto tx_error;
        }

        rcu_read_lock();
        if (ipv6_mod_enabled() && info->mode & IP_TUNNEL_INFO_IPV6)
                err = bareudp6_xmit_skb(skb, dev, bareudp, info);
        else
                err = bareudp_xmit_skb(skb, dev, bareudp, info);

        rcu_read_unlock();

        if (likely(!err))
                return NETDEV_TX_OK;
tx_error:
        dev_kfree_skb(skb);

        if (err == -ELOOP)
                DEV_STATS_INC(dev, collisions);
        else if (err == -ENETUNREACH)
                DEV_STATS_INC(dev, tx_carrier_errors);

        DEV_STATS_INC(dev, tx_errors);
        return NETDEV_TX_OK;
}

static int bareudp_fill_metadata_dst(struct net_device *dev,
                                     struct sk_buff *skb)
{
        struct ip_tunnel_info *info = skb_tunnel_info(skb);
        struct bareudp_dev *bareudp = netdev_priv(dev);
        bool use_cache;
        __be16 sport;

        use_cache = ip_tunnel_dst_cache_usable(skb, info);
        sport = udp_flow_src_port(bareudp->net, skb,
                                  bareudp->sport_min, USHRT_MAX,
                                  true);

        if (!ipv6_mod_enabled() || ip_tunnel_info_af(info) == AF_INET) {
                struct rtable *rt;
                __be32 saddr;

                rt = udp_tunnel_dst_lookup(skb, dev, bareudp->net, 0, &saddr,
                                           &info->key, sport, bareudp->port,
                                           info->key.tos,
                                           use_cache ? &info->dst_cache : NULL);
                if (IS_ERR(rt))
                        return PTR_ERR(rt);

                ip_rt_put(rt);
                info->key.u.ipv4.src = saddr;
        } else if (ip_tunnel_info_af(info) == AF_INET6) {
                struct dst_entry *dst;
                struct in6_addr saddr;
                struct socket *sock = rcu_dereference(bareudp->sock);

                dst = udp_tunnel6_dst_lookup(skb, dev, bareudp->net, sock,
                                             0, &saddr, &info->key,
                                             sport, bareudp->port, info->key.tos,
                                             use_cache ? &info->dst_cache : NULL);
                if (IS_ERR(dst))
                        return PTR_ERR(dst);

                dst_release(dst);
                info->key.u.ipv6.src = saddr;
        } else {
                return -EINVAL;
        }

        info->key.tp_src = sport;
        info->key.tp_dst = bareudp->port;
        return 0;
}

static const struct net_device_ops bareudp_netdev_ops = {
        .ndo_init               = bareudp_init,
        .ndo_uninit             = bareudp_uninit,
        .ndo_open               = bareudp_open,
        .ndo_stop               = bareudp_stop,
        .ndo_start_xmit         = bareudp_xmit,
        .ndo_fill_metadata_dst  = bareudp_fill_metadata_dst,
};

static const struct nla_policy bareudp_policy[IFLA_BAREUDP_MAX + 1] = {
        [IFLA_BAREUDP_PORT]                = { .type = NLA_U16 },
        [IFLA_BAREUDP_ETHERTYPE]           = { .type = NLA_U16 },
        [IFLA_BAREUDP_SRCPORT_MIN]         = { .type = NLA_U16 },
        [IFLA_BAREUDP_MULTIPROTO_MODE]     = { .type = NLA_FLAG },
};

/* Info for udev, that this is a virtual tunnel endpoint */
static const struct device_type bareudp_type = {
        .name = "bareudp",
};

/* Initialize the device structure. */
static void bareudp_setup(struct net_device *dev)
{
        dev->netdev_ops = &bareudp_netdev_ops;
        dev->needs_free_netdev = true;
        SET_NETDEV_DEVTYPE(dev, &bareudp_type);
        dev->features    |= NETIF_F_SG | NETIF_F_HW_CSUM | NETIF_F_FRAGLIST;
        dev->features    |= NETIF_F_RXCSUM;
        dev->features    |= NETIF_F_GSO_SOFTWARE;
        dev->hw_features |= NETIF_F_SG | NETIF_F_HW_CSUM | NETIF_F_FRAGLIST;
        dev->hw_features |= NETIF_F_RXCSUM;
        dev->hw_features |= NETIF_F_GSO_SOFTWARE;
        dev->hard_header_len = 0;
        dev->addr_len = 0;
        dev->mtu = ETH_DATA_LEN;
        dev->min_mtu = IPV4_MIN_MTU;
        dev->max_mtu = IP_MAX_MTU - BAREUDP_BASE_HLEN;
        dev->type = ARPHRD_NONE;
        netif_keep_dst(dev);
        dev->priv_flags |= IFF_NO_QUEUE;
        dev->lltx = true;
        dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
        dev->pcpu_stat_type = NETDEV_PCPU_STAT_DSTATS;
}

static int bareudp_validate(struct nlattr *tb[], struct nlattr *data[],
                            struct netlink_ext_ack *extack)
{
        if (!data) {
                NL_SET_ERR_MSG(extack,
                               "Not enough attributes provided to perform the operation");
                return -EINVAL;
        }
        return 0;
}

static int bareudp2info(struct nlattr *data[], struct bareudp_conf *conf,
                        struct netlink_ext_ack *extack)
{
        memset(conf, 0, sizeof(*conf));

        if (!data[IFLA_BAREUDP_PORT]) {
                NL_SET_ERR_MSG(extack, "port not specified");
                return -EINVAL;
        }
        if (!data[IFLA_BAREUDP_ETHERTYPE]) {
                NL_SET_ERR_MSG(extack, "ethertype not specified");
                return -EINVAL;
        }

        conf->port = nla_get_u16(data[IFLA_BAREUDP_PORT]);
        conf->ethertype = nla_get_u16(data[IFLA_BAREUDP_ETHERTYPE]);

        if (data[IFLA_BAREUDP_SRCPORT_MIN])
                conf->sport_min =  nla_get_u16(data[IFLA_BAREUDP_SRCPORT_MIN]);

        if (data[IFLA_BAREUDP_MULTIPROTO_MODE])
                conf->multi_proto_mode = true;

        return 0;
}

static struct bareudp_dev *bareudp_find_dev(struct bareudp_net *bn,
                                            const struct bareudp_conf *conf)
{
        struct bareudp_dev *bareudp, *t = NULL;

        list_for_each_entry(bareudp, &bn->bareudp_list, next) {
                if (conf->port == bareudp->port)
                        t = bareudp;
        }
        return t;
}

static int bareudp_configure(struct net *net, struct net_device *dev,
                             struct bareudp_conf *conf,
                             struct netlink_ext_ack *extack)
{
        struct bareudp_net *bn = net_generic(net, bareudp_net_id);
        struct bareudp_dev *t, *bareudp = netdev_priv(dev);
        int err;

        bareudp->net = net;
        bareudp->dev = dev;
        t = bareudp_find_dev(bn, conf);
        if (t) {
                NL_SET_ERR_MSG(extack, "Another bareudp device using the same port already exists");
                return -EBUSY;
        }

        if (conf->multi_proto_mode &&
            (conf->ethertype != htons(ETH_P_MPLS_UC) &&
             conf->ethertype != htons(ETH_P_IP))) {
                NL_SET_ERR_MSG(extack, "Cannot set multiproto mode for this ethertype (only IPv4 and unicast MPLS are supported)");
                return -EINVAL;
        }

        bareudp->port = conf->port;
        bareudp->ethertype = conf->ethertype;
        bareudp->sport_min = conf->sport_min;
        bareudp->multi_proto_mode = conf->multi_proto_mode;

        err = register_netdevice(dev);
        if (err)
                return err;

        list_add(&bareudp->next, &bn->bareudp_list);
        return 0;
}

static int bareudp_link_config(struct net_device *dev,
                               struct nlattr *tb[])
{
        int err;

        if (tb[IFLA_MTU]) {
                err = dev_set_mtu(dev, nla_get_u32(tb[IFLA_MTU]));
                if (err)
                        return err;
        }
        return 0;
}

static void bareudp_dellink(struct net_device *dev, struct list_head *head)
{
        struct bareudp_dev *bareudp = netdev_priv(dev);

        list_del(&bareudp->next);
        unregister_netdevice_queue(dev, head);
}

static int bareudp_newlink(struct net_device *dev,
                           struct rtnl_newlink_params *params,
                           struct netlink_ext_ack *extack)
{
        struct net *link_net = rtnl_newlink_link_net(params);
        struct nlattr **data = params->data;
        struct nlattr **tb = params->tb;
        struct bareudp_conf conf;
        int err;

        err = bareudp2info(data, &conf, extack);
        if (err)
                return err;

        err = bareudp_configure(link_net, dev, &conf, extack);
        if (err)
                return err;

        err = bareudp_link_config(dev, tb);
        if (err)
                goto err_unconfig;

        return 0;

err_unconfig:
        bareudp_dellink(dev, NULL);
        return err;
}

static size_t bareudp_get_size(const struct net_device *dev)
{
        return  nla_total_size(sizeof(__be16)) +  /* IFLA_BAREUDP_PORT */
                nla_total_size(sizeof(__be16)) +  /* IFLA_BAREUDP_ETHERTYPE */
                nla_total_size(sizeof(__u16))  +  /* IFLA_BAREUDP_SRCPORT_MIN */
                nla_total_size(0)              +  /* IFLA_BAREUDP_MULTIPROTO_MODE */
                0;
}

static int bareudp_fill_info(struct sk_buff *skb, const struct net_device *dev)
{
        struct bareudp_dev *bareudp = netdev_priv(dev);

        if (nla_put_be16(skb, IFLA_BAREUDP_PORT, bareudp->port))
                goto nla_put_failure;
        if (nla_put_be16(skb, IFLA_BAREUDP_ETHERTYPE, bareudp->ethertype))
                goto nla_put_failure;
        if (nla_put_u16(skb, IFLA_BAREUDP_SRCPORT_MIN, bareudp->sport_min))
                goto nla_put_failure;
        if (bareudp->multi_proto_mode &&
            nla_put_flag(skb, IFLA_BAREUDP_MULTIPROTO_MODE))
                goto nla_put_failure;

        return 0;

nla_put_failure:
        return -EMSGSIZE;
}

static struct rtnl_link_ops bareudp_link_ops __read_mostly = {
        .kind           = "bareudp",
        .maxtype        = IFLA_BAREUDP_MAX,
        .policy         = bareudp_policy,
        .priv_size      = sizeof(struct bareudp_dev),
        .setup          = bareudp_setup,
        .validate       = bareudp_validate,
        .newlink        = bareudp_newlink,
        .dellink        = bareudp_dellink,
        .get_size       = bareudp_get_size,
        .fill_info      = bareudp_fill_info,
};

static __net_init int bareudp_init_net(struct net *net)
{
        struct bareudp_net *bn = net_generic(net, bareudp_net_id);

        INIT_LIST_HEAD(&bn->bareudp_list);
        return 0;
}

static void __net_exit bareudp_exit_rtnl_net(struct net *net,
                                             struct list_head *dev_kill_list)
{
        struct bareudp_net *bn = net_generic(net, bareudp_net_id);
        struct bareudp_dev *bareudp, *next;

        list_for_each_entry_safe(bareudp, next, &bn->bareudp_list, next)
                bareudp_dellink(bareudp->dev, dev_kill_list);
}

static struct pernet_operations bareudp_net_ops = {
        .init = bareudp_init_net,
        .exit_rtnl = bareudp_exit_rtnl_net,
        .id   = &bareudp_net_id,
        .size = sizeof(struct bareudp_net),
};

static int __init bareudp_init_module(void)
{
        int rc;

        rc = register_pernet_subsys(&bareudp_net_ops);
        if (rc)
                goto out1;

        rc = rtnl_link_register(&bareudp_link_ops);
        if (rc)
                goto out2;

        return 0;
out2:
        unregister_pernet_subsys(&bareudp_net_ops);
out1:
        return rc;
}
late_initcall(bareudp_init_module);

static void __exit bareudp_cleanup_module(void)
{
        rtnl_link_unregister(&bareudp_link_ops);
        unregister_pernet_subsys(&bareudp_net_ops);
}
module_exit(bareudp_cleanup_module);

MODULE_ALIAS_RTNL_LINK("bareudp");
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Martin Varghese <martin.varghese@nokia.com>");
MODULE_DESCRIPTION("Interface driver for UDP encapsulated traffic");