Implement VXLAN-GPE. Only L2 mode (i.e. encapsulated Ethernet frame) is
supported by this patch.

L3 mode will be added by subsequent patches.

Signed-off-by: Jiri Benc <jb...@redhat.com>
---
 drivers/net/vxlan.c          | 68 ++++++++++++++++++++++++++++++++++++++++++--
 include/net/vxlan.h          | 62 +++++++++++++++++++++++++++++++++++++++-
 include/uapi/linux/if_link.h |  8 ++++++
 3 files changed, 135 insertions(+), 3 deletions(-)

diff --git a/drivers/net/vxlan.c b/drivers/net/vxlan.c
index 775ddb48388d..c7844bae339d 100644
--- a/drivers/net/vxlan.c
+++ b/drivers/net/vxlan.c
@@ -1192,6 +1192,33 @@ out:
        unparsed->vx_flags &= ~VXLAN_GBP_USED_BITS;
 }
 
+static bool vxlan_parse_gpe_hdr(struct vxlanhdr *unparsed,
+                               struct sk_buff *skb, u32 vxflags)
+{
+       struct vxlanhdr_gpe *gpe = (struct vxlanhdr_gpe *)unparsed;
+
+       /* Need to have Next Protocol set for interfaces in GPE mode. */
+       if (!gpe->np_applied)
+               return false;
+       /* "The initial version is 0. If a receiver does not support the
+        * version indicated it MUST drop the packet.
+        */
+       if (gpe->version != 0)
+               return false;
+       /* "When the O bit is set to 1, the packet is an OAM packet and OAM
+        * processing MUST occur." However, we don't implement OAM
+        * processing, thus drop the packet.
+        */
+       if (gpe->oam_flag)
+               return false;
+
+       if (gpe->next_protocol != VXLAN_GPE_NP_ETHERNET)
+               return false;
+
+       unparsed->vx_flags &= ~VXLAN_GPE_USED_BITS;
+       return true;
+}
+
 static bool vxlan_set_mac(struct vxlan_dev *vxlan,
                          struct vxlan_sock *vs,
                          struct sk_buff *skb)
@@ -1307,6 +1334,9 @@ static int vxlan_rcv(struct sock *sk, struct sk_buff *skb)
        /* For backwards compatibility, only allow reserved fields to be
         * used by VXLAN extensions if explicitly requested.
         */
+       if (vs->flags & VXLAN_F_GPE)
+               if (!vxlan_parse_gpe_hdr(&unparsed, skb, vs->flags))
+                       goto drop;
        if (vs->flags & VXLAN_F_REMCSUM_RX)
                if (!vxlan_remcsum(&unparsed, skb, vs->flags))
                        goto drop;
@@ -1685,6 +1715,14 @@ static void vxlan_build_gbp_hdr(struct vxlanhdr *vxh, 
u32 vxflags,
        gbp->policy_id = htons(md->gbp & VXLAN_GBP_ID_MASK);
 }
 
+static void vxlan_build_gpe_hdr(struct vxlanhdr *vxh, u32 vxflags)
+{
+       struct vxlanhdr_gpe *gpe = (struct vxlanhdr_gpe *)vxh;
+
+       gpe->np_applied = 1;
+       gpe->next_protocol = VXLAN_GPE_NP_ETHERNET;
+}
+
 static int vxlan_build_skb(struct sk_buff *skb, struct dst_entry *dst,
                           int iphdr_len, __be32 vni,
                           struct vxlan_metadata *md, u32 vxflags,
@@ -1744,6 +1782,8 @@ static int vxlan_build_skb(struct sk_buff *skb, struct 
dst_entry *dst,
 
        if (vxflags & VXLAN_F_GBP)
                vxlan_build_gbp_hdr(vxh, vxflags, md);
+       if (vxflags & VXLAN_F_GPE)
+               vxlan_build_gpe_hdr(vxh, vxflags);
 
        skb_set_inner_protocol(skb, htons(ETH_P_TEB));
        return 0;
@@ -2515,6 +2555,7 @@ static const struct nla_policy 
vxlan_policy[IFLA_VXLAN_MAX + 1] = {
        [IFLA_VXLAN_REMCSUM_RX] = { .type = NLA_U8 },
        [IFLA_VXLAN_GBP]        = { .type = NLA_FLAG, },
        [IFLA_VXLAN_REMCSUM_NOPARTIAL]  = { .type = NLA_FLAG },
+       [IFLA_VXLAN_GPE_MODE]   = { .type = NLA_U8, },
 };
 
 static int vxlan_validate(struct nlattr *tb[], struct nlattr *data[])
@@ -2714,6 +2755,10 @@ static int vxlan_dev_configure(struct net *src_net, 
struct net_device *dev,
        __be16 default_port = vxlan->cfg.dst_port;
        struct net_device *lowerdev = NULL;
 
+       if (((conf->flags & VXLAN_F_LEARN) && (conf->flags & VXLAN_F_GPE)) ||
+           ((conf->flags & VXLAN_F_GBP) && (conf->flags & VXLAN_F_GPE)))
+               return -EINVAL;
+
        vxlan->net = src_net;
 
        dst->remote_vni = conf->vni;
@@ -2770,8 +2815,12 @@ static int vxlan_dev_configure(struct net *src_net, 
struct net_device *dev,
        dev->needed_headroom = needed_headroom;
 
        memcpy(&vxlan->cfg, conf, sizeof(*conf));
-       if (!vxlan->cfg.dst_port)
-               vxlan->cfg.dst_port = default_port;
+       if (!vxlan->cfg.dst_port) {
+               if (conf->flags & VXLAN_F_GPE)
+                       vxlan->cfg.dst_port = 4790; /* IANA assigned VXLAN-GPE 
port */
+               else
+                       vxlan->cfg.dst_port = default_port;
+       }
        vxlan->flags |= conf->flags;
 
        if (!vxlan->cfg.age_interval)
@@ -2941,6 +2990,13 @@ static int vxlan_newlink(struct net *src_net, struct 
net_device *dev,
        if (data[IFLA_VXLAN_REMCSUM_NOPARTIAL])
                conf.flags |= VXLAN_F_REMCSUM_NOPARTIAL;
 
+       if (data[IFLA_VXLAN_GPE_MODE]) {
+               u8 mode = nla_get_u8(data[IFLA_VXLAN_GPE_MODE]);
+
+               if (mode > 0 && mode <= VXLAN_GPE_MODE_MAX)
+                       conf.flags |= VXLAN_F_GPE;
+       }
+
        err = vxlan_dev_configure(src_net, dev, &conf);
        switch (err) {
        case -ENODEV:
@@ -2954,6 +3010,10 @@ static int vxlan_newlink(struct net *src_net, struct 
net_device *dev,
        case -EEXIST:
                pr_info("duplicate VNI %u\n", be32_to_cpu(conf.vni));
                break;
+
+       case -EINVAL:
+               pr_info("unsupported combination of extensions\n");
+               break;
        }
 
        return err;
@@ -3083,6 +3143,10 @@ static int vxlan_fill_info(struct sk_buff *skb, const 
struct net_device *dev)
            nla_put_flag(skb, IFLA_VXLAN_REMCSUM_NOPARTIAL))
                goto nla_put_failure;
 
+       if (vxlan->flags & VXLAN_F_GPE &&
+           nla_put_u8(skb, IFLA_VXLAN_GPE_MODE, VXLAN_GPE_MODE_L2))
+               goto nla_put_failure;
+
        return 0;
 
 nla_put_failure:
diff --git a/include/net/vxlan.h b/include/net/vxlan.h
index 6eda4ed4d78b..7c5f1385bdfd 100644
--- a/include/net/vxlan.h
+++ b/include/net/vxlan.h
@@ -119,6 +119,64 @@ struct vxlanhdr_gbp {
 #define VXLAN_GBP_POLICY_APPLIED       (BIT(3) << 16)
 #define VXLAN_GBP_ID_MASK              (0xFFFF)
 
+/*
+ * VXLAN Generic Protocol Extension (VXLAN_F_GPE):
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |R|R|Ver|I|P|R|O|       Reserved                |Next Protocol  |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |                VXLAN Network Identifier (VNI) |   Reserved    |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *
+ * Ver = Version. Indicates VXLAN GPE protocol version.
+ *
+ * P = Next Protocol Bit. The P bit is set to indicate that the
+ *     Next Protocol field is present.
+ *
+ * O = OAM Flag Bit. The O bit is set to indicate that the packet
+ *     is an OAM packet.
+ *
+ * Next Protocol = This 8 bit field indicates the protocol header
+ * immediately following the VXLAN GPE header.
+ *
+ * https://tools.ietf.org/html/draft-ietf-nvo3-vxlan-gpe-01
+ */
+
+struct vxlanhdr_gpe {
+#if defined(__LITTLE_ENDIAN_BITFIELD)
+       u8      oam_flag:1,
+               reserved_flags1:1,
+               np_applied:1,
+               instance_applied:1,
+               version:2,
+reserved_flags2:2;
+#elif defined(__BIG_ENDIAN_BITFIELD)
+       u8      reserved_flags2:2,
+               version:2,
+               instance_applied:1,
+               np_applied:1,
+               reserved_flags1:1,
+               oam_flag:1;
+#endif
+       u8      reserved_flags3;
+       u8      reserved_flags4;
+       u8      next_protocol;
+       __be32  vx_vni;
+};
+
+/* VXLAN-GPE header flags. */
+#define VXLAN_HF_VER   cpu_to_be32(BIT(29) | BIT(28))
+#define VXLAN_HF_NP    cpu_to_be32(BIT(26))
+#define VXLAN_HF_OAM   cpu_to_be32(BIT(24))
+
+#define VXLAN_GPE_USED_BITS (VXLAN_HF_VER | VXLAN_HF_NP | VXLAN_HF_OAM | \
+                            cpu_to_be32(0xff))
+
+/* VXLAN-GPE header Next Protocol. */
+#define VXLAN_GPE_NP_IPV4      0x01
+#define VXLAN_GPE_NP_IPV6      0x02
+#define VXLAN_GPE_NP_ETHERNET  0x03
+#define VXLAN_GPE_NP_NSH       0x04
+
 struct vxlan_metadata {
        u32             gbp;
 };
@@ -205,6 +263,7 @@ struct vxlan_dev {
 #define VXLAN_F_GBP                    0x800
 #define VXLAN_F_REMCSUM_NOPARTIAL      0x1000
 #define VXLAN_F_COLLECT_METADATA       0x2000
+#define VXLAN_F_GPE                    0x4000
 
 /* Flags that are used in the receive path. These flags must match in
  * order for a socket to be shareable
@@ -213,7 +272,8 @@ struct vxlan_dev {
                                         VXLAN_F_UDP_ZERO_CSUM6_RX |    \
                                         VXLAN_F_REMCSUM_RX |           \
                                         VXLAN_F_REMCSUM_NOPARTIAL |    \
-                                        VXLAN_F_COLLECT_METADATA)
+                                        VXLAN_F_COLLECT_METADATA |     \
+                                        VXLAN_F_GPE)
 
 struct net_device *vxlan_dev_create(struct net *net, const char *name,
                                    u8 name_assign_type, struct vxlan_config 
*conf);
diff --git a/include/uapi/linux/if_link.h b/include/uapi/linux/if_link.h
index d452cea59020..c2b2b7462731 100644
--- a/include/uapi/linux/if_link.h
+++ b/include/uapi/linux/if_link.h
@@ -456,10 +456,18 @@ enum {
        IFLA_VXLAN_GBP,
        IFLA_VXLAN_REMCSUM_NOPARTIAL,
        IFLA_VXLAN_COLLECT_METADATA,
+       IFLA_VXLAN_GPE_MODE,
        __IFLA_VXLAN_MAX
 };
 #define IFLA_VXLAN_MAX (__IFLA_VXLAN_MAX - 1)
 
+enum vxlan_gpe_mode {
+       VXLAN_GPE_MODE_DISABLED = 0,
+       VXLAN_GPE_MODE_L2,
+       __VXLAN_GPE_MODE_MAX
+};
+#define VXLAN_GPE_MODE_MAX (__VXLAN_GPE_MODE_MAX - 1)
+
 struct ifla_vxlan_port_range {
        __be16  low;
        __be16  high;
-- 
1.8.3.1

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