net: Add Geneve tunneling protocol driver

This adds a device level support for Geneve -- Generic Network
Virtualization Encapsulation. The protocol is documented at
http://tools.ietf.org/html/draft-gross-geneve-01

Only protocol layer Geneve support is provided by this driver.
Openvswitch can be used for configuring, set up and tear down
functional Geneve tunnels.

Signed-off-by: Jesse Gross <jesse@nicira.com>
Signed-off-by: Andy Zhou <azhou@nicira.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 373 insertions, 0 deletions

diff --git a/net/ipv4/geneve.c b/net/ipv4/geneve.c
new file mode 100644
index 000000000000..f008c5515f48
--- /dev/null
+++ b/net/ipv4/geneve.c
@@ -0,0 +1,373 @@
+/*
+ * Geneve: Generic Network Virtualization Encapsulation
+ *
+ * Copyright (c) 2014 Nicira, Inc.
+ *
+ * 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.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/kernel.h>
+#include <linux/types.h>
+#include <linux/module.h>
+#include <linux/errno.h>
+#include <linux/slab.h>
+#include <linux/skbuff.h>
+#include <linux/rculist.h>
+#include <linux/netdevice.h>
+#include <linux/in.h>
+#include <linux/ip.h>
+#include <linux/udp.h>
+#include <linux/igmp.h>
+#include <linux/etherdevice.h>
+#include <linux/if_ether.h>
+#include <linux/if_vlan.h>
+#include <linux/hash.h>
+#include <linux/ethtool.h>
+#include <net/arp.h>
+#include <net/ndisc.h>
+#include <net/ip.h>
+#include <net/ip_tunnels.h>
+#include <net/icmp.h>
+#include <net/udp.h>
+#include <net/rtnetlink.h>
+#include <net/route.h>
+#include <net/dsfield.h>
+#include <net/inet_ecn.h>
+#include <net/net_namespace.h>
+#include <net/netns/generic.h>
+#include <net/geneve.h>
+#include <net/protocol.h>
+#include <net/udp_tunnel.h>
+#if IS_ENABLED(CONFIG_IPV6)
+#include <net/ipv6.h>
+#include <net/addrconf.h>
+#include <net/ip6_tunnel.h>
+#include <net/ip6_checksum.h>
+#endif
+
+#define PORT_HASH_BITS 8
+#define PORT_HASH_SIZE (1<<PORT_HASH_BITS)
+
+/* per-network namespace private data for this module */
+struct geneve_net {
+        struct hlist_head       sock_list[PORT_HASH_SIZE];
+        spinlock_t              sock_lock;   /* Protects sock_list */
+};
+
+static int geneve_net_id;
+
+static struct workqueue_struct *geneve_wq;
+
+static inline struct genevehdr *geneve_hdr(const struct sk_buff *skb)
+{
+        return (struct genevehdr *)(udp_hdr(skb) + 1);
+}
+
+static struct hlist_head *gs_head(struct net *net, __be16 port)
+{
+        struct geneve_net *gn = net_generic(net, geneve_net_id);
+
+        return &gn->sock_list[hash_32(ntohs(port), PORT_HASH_BITS)];
+}
+
+/* Find geneve socket based on network namespace and UDP port */
+static struct geneve_sock *geneve_find_sock(struct net *net, __be16 port)
+{
+        struct geneve_sock *gs;
+
+        hlist_for_each_entry_rcu(gs, gs_head(net, port), hlist) {
+                if (inet_sk(gs->sock->sk)->inet_sport == port)
+                        return gs;
+        }
+
+        return NULL;
+}
+
+static void geneve_build_header(struct genevehdr *geneveh,
+                                __be16 tun_flags, u8 vni[3],
+                                u8 options_len, u8 *options)
+{
+        geneveh->ver = GENEVE_VER;
+        geneveh->opt_len = options_len / 4;
+        geneveh->oam = !!(tun_flags & TUNNEL_OAM);
+        geneveh->critical = !!(tun_flags & TUNNEL_CRIT_OPT);
+        geneveh->rsvd1 = 0;
+        memcpy(geneveh->vni, vni, 3);
+        geneveh->proto_type = htons(ETH_P_TEB);
+        geneveh->rsvd2 = 0;
+
+        memcpy(geneveh->options, options, options_len);
+}
+
+/* Transmit a fully formated Geneve frame.
+ *
+ * When calling this function. The skb->data should point
+ * to the geneve header which is fully formed.
+ *
+ * This function will add other UDP tunnel headers.
+ */
+int geneve_xmit_skb(struct geneve_sock *gs, struct rtable *rt,
+                    struct sk_buff *skb, __be32 src, __be32 dst, __u8 tos,
+                    __u8 ttl, __be16 df, __be16 src_port, __be16 dst_port,
+                    __be16 tun_flags, u8 vni[3], u8 opt_len, u8 *opt,
+                    bool xnet)
+{
+        struct genevehdr *gnvh;
+        int min_headroom;
+        int err;
+
+        skb = udp_tunnel_handle_offloads(skb, !gs->sock->sk->sk_no_check_tx);
+
+        min_headroom = LL_RESERVED_SPACE(rt->dst.dev) + rt->dst.header_len
+                        + GENEVE_BASE_HLEN + opt_len + sizeof(struct iphdr)
+                        + (vlan_tx_tag_present(skb) ? VLAN_HLEN : 0);
+
+        err = skb_cow_head(skb, min_headroom);
+        if (unlikely(err))
+                return err;
+
+        if (vlan_tx_tag_present(skb)) {
+                if (unlikely(!__vlan_put_tag(skb,
+                                             skb->vlan_proto,
+                                             vlan_tx_tag_get(skb)))) {
+                        err = -ENOMEM;
+                        return err;
+                }
+                skb->vlan_tci = 0;
+        }
+
+        gnvh = (struct genevehdr *)__skb_push(skb, sizeof(*gnvh) + opt_len);
+        geneve_build_header(gnvh, tun_flags, vni, opt_len, opt);
+
+        return udp_tunnel_xmit_skb(gs->sock, rt, skb, src, dst,
+                                   tos, ttl, df, src_port, dst_port, xnet);
+}
+EXPORT_SYMBOL_GPL(geneve_xmit_skb);
+
+static void geneve_notify_add_rx_port(struct geneve_sock *gs)
+{
+        struct sock *sk = gs->sock->sk;
+        sa_family_t sa_family = sk->sk_family;
+        int err;
+
+        if (sa_family == AF_INET) {
+                err = udp_add_offload(&gs->udp_offloads);
+                if (err)
+                        pr_warn("geneve: udp_add_offload failed with status %d\n",
+                                err);
+        }
+}
+
+/* Callback from net/ipv4/udp.c to receive packets */
+static int geneve_udp_encap_recv(struct sock *sk, struct sk_buff *skb)
+{
+        struct genevehdr *geneveh;
+        struct geneve_sock *gs;
+        int opts_len;
+
+        /* Need Geneve and inner Ethernet header to be present */
+        if (unlikely(!pskb_may_pull(skb, GENEVE_BASE_HLEN)))
+                goto error;
+
+        /* Return packets with reserved bits set */
+        geneveh = geneve_hdr(skb);
+
+        if (unlikely(geneveh->ver != GENEVE_VER))
+                goto error;
+
+        if (unlikely(geneveh->proto_type != htons(ETH_P_TEB)))
+                goto error;
+
+        opts_len = geneveh->opt_len * 4;
+        if (iptunnel_pull_header(skb, GENEVE_BASE_HLEN + opts_len,
+                                 htons(ETH_P_TEB)))
+                goto drop;
+
+        gs = rcu_dereference_sk_user_data(sk);
+        if (!gs)
+                goto drop;
+
+        gs->rcv(gs, skb);
+        return 0;
+
+drop:
+        /* Consume bad packet */
+        kfree_skb(skb);
+        return 0;
+
+error:
+        /* Let the UDP layer deal with the skb */
+        return 1;
+}
+
+static void geneve_del_work(struct work_struct *work)
+{
+        struct geneve_sock *gs = container_of(work, struct geneve_sock,
+                                              del_work);
+
+        udp_tunnel_sock_release(gs->sock);
+        kfree_rcu(gs, rcu);
+}
+
+static struct socket *geneve_create_sock(struct net *net, bool ipv6,
+                                         __be16 port)
+{
+        struct socket *sock;
+        struct udp_port_cfg udp_conf;
+        int err;
+
+        memset(&udp_conf, 0, sizeof(udp_conf));
+
+        if (ipv6) {
+                udp_conf.family = AF_INET6;
+        } else {
+                udp_conf.family = AF_INET;
+                udp_conf.local_ip.s_addr = INADDR_ANY;
+        }
+
+        udp_conf.local_udp_port = port;
+
+        /* Open UDP socket */
+        err = udp_sock_create(net, &udp_conf, &sock);
+        if (err < 0)
+                return ERR_PTR(err);
+
+        return sock;
+}
+
+/* Create new listen socket if needed */
+static struct geneve_sock *geneve_socket_create(struct net *net, __be16 port,
+                                                geneve_rcv_t *rcv, void *data,
+                                                bool ipv6)
+{
+        struct geneve_net *gn = net_generic(net, geneve_net_id);
+        struct geneve_sock *gs;
+        struct socket *sock;
+        struct udp_tunnel_sock_cfg tunnel_cfg;
+
+        gs = kzalloc(sizeof(*gs), GFP_KERNEL);
+        if (!gs)
+                return ERR_PTR(-ENOMEM);
+
+        INIT_WORK(&gs->del_work, geneve_del_work);
+
+        sock = geneve_create_sock(net, ipv6, port);
+        if (IS_ERR(sock)) {
+                kfree(gs);
+                return ERR_CAST(sock);
+        }
+
+        gs->sock = sock;
+        atomic_set(&gs->refcnt, 1);
+        gs->rcv = rcv;
+        gs->rcv_data = data;
+
+        /* Initialize the geneve udp offloads structure */
+        gs->udp_offloads.port = port;
+        gs->udp_offloads.callbacks.gro_receive = NULL;
+        gs->udp_offloads.callbacks.gro_complete = NULL;
+
+        spin_lock(&gn->sock_lock);
+        hlist_add_head_rcu(&gs->hlist, gs_head(net, port));
+        geneve_notify_add_rx_port(gs);
+        spin_unlock(&gn->sock_lock);
+
+        /* Mark socket as an encapsulation socket */
+        tunnel_cfg.sk_user_data = gs;
+        tunnel_cfg.encap_type = 1;
+        tunnel_cfg.encap_rcv = geneve_udp_encap_recv;
+        tunnel_cfg.encap_destroy = NULL;
+        setup_udp_tunnel_sock(net, sock, &tunnel_cfg);
+
+        return gs;
+}
+
+struct geneve_sock *geneve_sock_add(struct net *net, __be16 port,
+                                    geneve_rcv_t *rcv, void *data,
+                                    bool no_share, bool ipv6)
+{
+        struct geneve_sock *gs;
+
+        gs = geneve_socket_create(net, port, rcv, data, ipv6);
+        if (!IS_ERR(gs))
+                return gs;
+
+        if (no_share)   /* Return error if sharing is not allowed. */
+                return ERR_PTR(-EINVAL);
+
+        gs = geneve_find_sock(net, port);
+        if (gs) {
+                if (gs->rcv == rcv)
+                        atomic_inc(&gs->refcnt);
+                else
+                        gs = ERR_PTR(-EBUSY);
+        } else {
+                gs = ERR_PTR(-EINVAL);
+        }
+
+        return gs;
+}
+EXPORT_SYMBOL_GPL(geneve_sock_add);
+
+void geneve_sock_release(struct geneve_sock *gs)
+{
+        if (!atomic_dec_and_test(&gs->refcnt))
+                return;
+
+        queue_work(geneve_wq, &gs->del_work);
+}
+EXPORT_SYMBOL_GPL(geneve_sock_release);
+
+static __net_init int geneve_init_net(struct net *net)
+{
+        struct geneve_net *gn = net_generic(net, geneve_net_id);
+        unsigned int h;
+
+        spin_lock_init(&gn->sock_lock);
+
+        for (h = 0; h < PORT_HASH_SIZE; ++h)
+                INIT_HLIST_HEAD(&gn->sock_list[h]);
+
+        return 0;
+}
+
+static struct pernet_operations geneve_net_ops = {
+        .init = geneve_init_net,
+        .exit = NULL,
+        .id   = &geneve_net_id,
+        .size = sizeof(struct geneve_net),
+};
+
+static int __init geneve_init_module(void)
+{
+        int rc;
+
+        geneve_wq = alloc_workqueue("geneve", 0, 0);
+        if (!geneve_wq)
+                return -ENOMEM;
+
+        rc = register_pernet_subsys(&geneve_net_ops);
+        if (rc)
+                return rc;
+
+        pr_info("Geneve driver\n");
+
+        return 0;
+}
+late_initcall(geneve_init_module);
+
+static void __exit geneve_cleanup_module(void)
+{
+        destroy_workqueue(geneve_wq);
+}
+module_exit(geneve_cleanup_module);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Jesse Gross <jesse@nicira.com>");
+MODULE_DESCRIPTION("Driver for GENEVE encapsulated traffic");
+MODULE_ALIAS_RTNL_LINK("geneve");