net: vxlan: Add nolocalbypass option to vxlan.

If a packet needs to be encapsulated towards a local destination IP, the
packet will undergo a "local bypass" and be injected into the Rx path as
if it was received by the target VXLAN device without undergoing
encapsulation. If such a device does not exist, the packet will be
dropped.

There are scenarios where we do not want to perform such a bypass, but
instead want the packet to be encapsulated and locally received by a
user space program for post-processing.

To that end, add a new VXLAN device attribute that controls whether a
"local bypass" is performed or not. Default to performing a bypass to
maintain existing behavior.

Signed-off-by: Vladimir Nikishkin <vladimir@nikishkin.pw>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/vxlan/vxlan_core.c b/drivers/net/vxlan/vxlan_core.c
index 561fe1b..7874454 100644 (file)
--- a/drivers/net/vxlan/vxlan_core.c
+++ b/drivers/net/vxlan/vxlan_core.c
@@ -2352,7 +2352,8 @@ static int encap_bypass_if_local(struct sk_buff *skb, struct net_device *dev,
 #endif
        /* Bypass encapsulation if the destination is local */
        if (rt_flags & RTCF_LOCAL &&
-           !(rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST))) {
+           !(rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST)) &&
+           vxlan->cfg.flags & VXLAN_F_LOCALBYPASS) {
                struct vxlan_dev *dst_vxlan;
 
                dst_release(dst);
@@ -3172,6 +3173,7 @@ static void vxlan_raw_setup(struct net_device *dev)
 }
 
 static const struct nla_policy vxlan_policy[IFLA_VXLAN_MAX + 1] = {
+       [IFLA_VXLAN_UNSPEC]     = { .strict_start_type = IFLA_VXLAN_LOCALBYPASS },
        [IFLA_VXLAN_ID]         = { .type = NLA_U32 },
        [IFLA_VXLAN_GROUP]      = { .len = sizeof_field(struct iphdr, daddr) },
        [IFLA_VXLAN_GROUP6]     = { .len = sizeof(struct in6_addr) },
@@ -3202,6 +3204,7 @@ static const struct nla_policy vxlan_policy[IFLA_VXLAN_MAX + 1] = {
        [IFLA_VXLAN_TTL_INHERIT]        = { .type = NLA_FLAG },
        [IFLA_VXLAN_DF]         = { .type = NLA_U8 },
        [IFLA_VXLAN_VNIFILTER]  = { .type = NLA_U8 },
+       [IFLA_VXLAN_LOCALBYPASS]        = NLA_POLICY_MAX(NLA_U8, 1),
 };
 
 static int vxlan_validate(struct nlattr *tb[], struct nlattr *data[],
@@ -4011,6 +4014,17 @@ static int vxlan_nl2conf(struct nlattr *tb[], struct nlattr *data[],
                        conf->flags |= VXLAN_F_UDP_ZERO_CSUM_TX;
        }
 
+       if (data[IFLA_VXLAN_LOCALBYPASS]) {
+               err = vxlan_nl2flag(conf, data, IFLA_VXLAN_LOCALBYPASS,
+                                   VXLAN_F_LOCALBYPASS, changelink,
+                                   true, extack);
+               if (err)
+                       return err;
+       } else if (!changelink) {
+               /* default to local bypass on a new device */
+               conf->flags |= VXLAN_F_LOCALBYPASS;
+       }
+
        if (data[IFLA_VXLAN_UDP_ZERO_CSUM6_TX]) {
                err = vxlan_nl2flag(conf, data, IFLA_VXLAN_UDP_ZERO_CSUM6_TX,
                                    VXLAN_F_UDP_ZERO_CSUM6_TX, changelink,
@@ -4232,6 +4246,7 @@ static size_t vxlan_get_size(const struct net_device *dev)
                nla_total_size(sizeof(__u8)) + /* IFLA_VXLAN_UDP_ZERO_CSUM6_RX */
                nla_total_size(sizeof(__u8)) + /* IFLA_VXLAN_REMCSUM_TX */
                nla_total_size(sizeof(__u8)) + /* IFLA_VXLAN_REMCSUM_RX */
+               nla_total_size(sizeof(__u8)) + /* IFLA_VXLAN_LOCALBYPASS */
                0;
 }
 
@@ -4308,7 +4323,9 @@ static int vxlan_fill_info(struct sk_buff *skb, const struct net_device *dev)
            nla_put_u8(skb, IFLA_VXLAN_REMCSUM_TX,
                       !!(vxlan->cfg.flags & VXLAN_F_REMCSUM_TX)) ||
            nla_put_u8(skb, IFLA_VXLAN_REMCSUM_RX,
-                      !!(vxlan->cfg.flags & VXLAN_F_REMCSUM_RX)))
+                      !!(vxlan->cfg.flags & VXLAN_F_REMCSUM_RX)) ||
+           nla_put_u8(skb, IFLA_VXLAN_LOCALBYPASS,
+                      !!(vxlan->cfg.flags & VXLAN_F_LOCALBYPASS)))
                goto nla_put_failure;
 
        if (nla_put(skb, IFLA_VXLAN_PORT_RANGE, sizeof(ports), &ports))

diff --git a/include/net/vxlan.h b/include/net/vxlan.h
index 20bd7d8..0be91ca 100644 (file)
--- a/include/net/vxlan.h
+++ b/include/net/vxlan.h
@@ -328,6 +328,7 @@ struct vxlan_dev {
 #define VXLAN_F_TTL_INHERIT            0x10000
 #define VXLAN_F_VNIFILTER               0x20000
 #define VXLAN_F_MDB                    0x40000
+#define VXLAN_F_LOCALBYPASS            0x80000
 
 /* Flags that are used in the receive path. These flags must match in
  * order for a socket to be shareable
@@ -348,7 +349,8 @@ struct vxlan_dev {
                                         VXLAN_F_UDP_ZERO_CSUM6_TX |    \
                                         VXLAN_F_UDP_ZERO_CSUM6_RX |    \
                                         VXLAN_F_COLLECT_METADATA  |    \
-                                        VXLAN_F_VNIFILTER)
+                                        VXLAN_F_VNIFILTER         |    \
+                                        VXLAN_F_LOCALBYPASS)
 
 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 4ac1000..0f6a0fe 100644 (file)
--- a/include/uapi/linux/if_link.h
+++ b/include/uapi/linux/if_link.h
@@ -828,6 +828,7 @@ enum {
        IFLA_VXLAN_TTL_INHERIT,
        IFLA_VXLAN_DF,
        IFLA_VXLAN_VNIFILTER, /* only applicable with COLLECT_METADATA mode */
+       IFLA_VXLAN_LOCALBYPASS,
        __IFLA_VXLAN_MAX
 };
 #define IFLA_VXLAN_MAX (__IFLA_VXLAN_MAX - 1)