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linux-stable/include/net/vxlan.h
Stefano Brivio b4d3069783 vxlan: Allow configuration of DF behaviour 
Allow users to set the IPv4 DF bit in outgoing packets, or to inherit its
value from the IPv4 inner header. If the encapsulated protocol is IPv6 and
DF is configured to be inherited, always set it.

For IPv4, inheriting DF from the inner header was probably intended from
the very beginning judging by the comment to vxlan_xmit(), but it wasn't
actually implemented -- also because it would have done more harm than
good, without handling for ICMP Fragmentation Needed messages.

According to RFC 7348, "Path MTU discovery MAY be used". An expired RFC
draft, draft-saum-nvo3-pmtud-over-vxlan-05, whose purpose was to describe
PMTUD implementation, says that "is a MUST that Vxlan gateways [...]
SHOULD set the DF-bit [...]", whatever that means.

Given this background, the only sane option is probably to let the user
decide, and keep the current behaviour as default.

This only applies to non-lwt tunnels: if an external control plane is
used, tunnel key will still control the DF flag.

v2:
- DF behaviour configuration only applies for non-lwt tunnels, move DF
  setting to if (!info) block in vxlan_xmit_one() (Stephen Hemminger)

Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Reviewed-by: Sabrina Dubroca <sd@queasysnail.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-11-08 17:13:08 -08:00

438 lines
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/* SPDX-License-Identifier: GPL-2.0 */
#ifndef __NET_VXLAN_H
#define __NET_VXLAN_H 1
#include <linux/if_vlan.h>
#include <net/udp_tunnel.h>
#include <net/dst_metadata.h>
#include <net/rtnetlink.h>
#include <net/switchdev.h>
/* VXLAN protocol (RFC 7348) header:
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* |R|R|R|R|I|R|R|R| Reserved |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | VXLAN Network Identifier (VNI) | Reserved |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
*
* I = VXLAN Network Identifier (VNI) present.
*/
struct vxlanhdr {
__be32 vx_flags;
__be32 vx_vni;
};
/* VXLAN header flags. */
#define VXLAN_HF_VNI cpu_to_be32(BIT(27))
#define VXLAN_N_VID (1u << 24)
#define VXLAN_VID_MASK (VXLAN_N_VID - 1)
#define VXLAN_VNI_MASK cpu_to_be32(VXLAN_VID_MASK << 8)
#define VXLAN_HLEN (sizeof(struct udphdr) + sizeof(struct vxlanhdr))
#define VNI_HASH_BITS 10
#define VNI_HASH_SIZE (1<<VNI_HASH_BITS)
#define FDB_HASH_BITS 8
#define FDB_HASH_SIZE (1<<FDB_HASH_BITS)
/* Remote checksum offload for VXLAN (VXLAN_F_REMCSUM_[RT]X):
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* |R|R|R|R|I|R|R|R|R|R|C| Reserved |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | VXLAN Network Identifier (VNI) |O| Csum start |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
*
* C = Remote checksum offload bit. When set indicates that the
* remote checksum offload data is present.
*
* O = Offset bit. Indicates the checksum offset relative to
* checksum start.
*
* Csum start = Checksum start divided by two.
*
* http://tools.ietf.org/html/draft-herbert-vxlan-rco
*/
/* VXLAN-RCO header flags. */
#define VXLAN_HF_RCO cpu_to_be32(BIT(21))
/* Remote checksum offload header option */
#define VXLAN_RCO_MASK cpu_to_be32(0x7f) /* Last byte of vni field */
#define VXLAN_RCO_UDP cpu_to_be32(0x80) /* Indicate UDP RCO (TCP when not set *) */
#define VXLAN_RCO_SHIFT 1 /* Left shift of start */
#define VXLAN_RCO_SHIFT_MASK ((1 << VXLAN_RCO_SHIFT) - 1)
#define VXLAN_MAX_REMCSUM_START (0x7f << VXLAN_RCO_SHIFT)
/*
* VXLAN Group Based Policy Extension (VXLAN_F_GBP):
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* |G|R|R|R|I|R|R|R|R|D|R|R|A|R|R|R| Group Policy ID |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | VXLAN Network Identifier (VNI) | Reserved |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
*
* G = Group Policy ID present.
*
* D = Don't Learn bit. When set, this bit indicates that the egress
* VTEP MUST NOT learn the source address of the encapsulated frame.
*
* A = Indicates that the group policy has already been applied to
* this packet. Policies MUST NOT be applied by devices when the
* A bit is set.
*
* https://tools.ietf.org/html/draft-smith-vxlan-group-policy
*/
struct vxlanhdr_gbp {
u8 vx_flags;
#ifdef __LITTLE_ENDIAN_BITFIELD
u8 reserved_flags1:3,
policy_applied:1,
reserved_flags2:2,
dont_learn:1,
reserved_flags3:1;
#elif defined(__BIG_ENDIAN_BITFIELD)
u8 reserved_flags1:1,
dont_learn:1,
reserved_flags2:2,
policy_applied:1,
reserved_flags3:3;
#else
#error "Please fix <asm/byteorder.h>"
#endif
__be16 policy_id;
__be32 vx_vni;
};
/* VXLAN-GBP header flags. */
#define VXLAN_HF_GBP cpu_to_be32(BIT(31))
#define VXLAN_GBP_USED_BITS (VXLAN_HF_GBP | cpu_to_be32(0xFFFFFF))
/* skb->mark mapping
*
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* |R|R|R|R|R|R|R|R|R|D|R|R|A|R|R|R| Group Policy ID |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
*/
#define VXLAN_GBP_DONT_LEARN (BIT(6) << 16)
#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))
struct vxlan_metadata {
u32 gbp;
};
/* per UDP socket information */
struct vxlan_sock {
struct hlist_node hlist;
struct socket *sock;
struct hlist_head vni_list[VNI_HASH_SIZE];
refcount_t refcnt;
u32 flags;
};
union vxlan_addr {
struct sockaddr_in sin;
struct sockaddr_in6 sin6;
struct sockaddr sa;
};
struct vxlan_rdst {
union vxlan_addr remote_ip;
__be16 remote_port;
u8 offloaded:1;
__be32 remote_vni;
u32 remote_ifindex;
struct list_head list;
struct rcu_head rcu;
struct dst_cache dst_cache;
};
struct vxlan_config {
union vxlan_addr remote_ip;
union vxlan_addr saddr;
__be32 vni;
int remote_ifindex;
int mtu;
__be16 dst_port;
u16 port_min;
u16 port_max;
u8 tos;
u8 ttl;
__be32 label;
u32 flags;
unsigned long age_interval;
unsigned int addrmax;
bool no_share;
enum ifla_vxlan_df df;
};
struct vxlan_dev_node {
struct hlist_node hlist;
struct vxlan_dev *vxlan;
};
/* Pseudo network device */
struct vxlan_dev {
struct vxlan_dev_node hlist4; /* vni hash table for IPv4 socket */
#if IS_ENABLED(CONFIG_IPV6)
struct vxlan_dev_node hlist6; /* vni hash table for IPv6 socket */
#endif
struct list_head next; /* vxlan's per namespace list */
struct vxlan_sock __rcu *vn4_sock; /* listening socket for IPv4 */
#if IS_ENABLED(CONFIG_IPV6)
struct vxlan_sock __rcu *vn6_sock; /* listening socket for IPv6 */
#endif
struct net_device *dev;
struct net *net; /* netns for packet i/o */
struct vxlan_rdst default_dst; /* default destination */
struct timer_list age_timer;
spinlock_t hash_lock;
unsigned int addrcnt;
struct gro_cells gro_cells;
struct vxlan_config cfg;
struct hlist_head fdb_head[FDB_HASH_SIZE];
};
#define VXLAN_F_LEARN 0x01
#define VXLAN_F_PROXY 0x02
#define VXLAN_F_RSC 0x04
#define VXLAN_F_L2MISS 0x08
#define VXLAN_F_L3MISS 0x10
#define VXLAN_F_IPV6 0x20
#define VXLAN_F_UDP_ZERO_CSUM_TX 0x40
#define VXLAN_F_UDP_ZERO_CSUM6_TX 0x80
#define VXLAN_F_UDP_ZERO_CSUM6_RX 0x100
#define VXLAN_F_REMCSUM_TX 0x200
#define VXLAN_F_REMCSUM_RX 0x400
#define VXLAN_F_GBP 0x800
#define VXLAN_F_REMCSUM_NOPARTIAL 0x1000
#define VXLAN_F_COLLECT_METADATA 0x2000
#define VXLAN_F_GPE 0x4000
#define VXLAN_F_IPV6_LINKLOCAL 0x8000
#define VXLAN_F_TTL_INHERIT 0x10000
/* Flags that are used in the receive path. These flags must match in
* order for a socket to be shareable
*/
#define VXLAN_F_RCV_FLAGS (VXLAN_F_GBP | \
VXLAN_F_GPE | \
VXLAN_F_UDP_ZERO_CSUM6_RX | \
VXLAN_F_REMCSUM_RX | \
VXLAN_F_REMCSUM_NOPARTIAL | \
VXLAN_F_COLLECT_METADATA)
/* Flags that can be set together with VXLAN_F_GPE. */
#define VXLAN_F_ALLOWED_GPE (VXLAN_F_GPE | \
VXLAN_F_IPV6 | \
VXLAN_F_IPV6_LINKLOCAL | \
VXLAN_F_UDP_ZERO_CSUM_TX | \
VXLAN_F_UDP_ZERO_CSUM6_TX | \
VXLAN_F_UDP_ZERO_CSUM6_RX | \
VXLAN_F_COLLECT_METADATA)
struct net_device *vxlan_dev_create(struct net *net, const char *name,
u8 name_assign_type, struct vxlan_config *conf);
static inline netdev_features_t vxlan_features_check(struct sk_buff *skb,
netdev_features_t features)
{
u8 l4_hdr = 0;
if (!skb->encapsulation)
return features;
switch (vlan_get_protocol(skb)) {
case htons(ETH_P_IP):
l4_hdr = ip_hdr(skb)->protocol;
break;
case htons(ETH_P_IPV6):
l4_hdr = ipv6_hdr(skb)->nexthdr;
break;
default:
return features;
}
if ((l4_hdr == IPPROTO_UDP) &&
(skb->inner_protocol_type != ENCAP_TYPE_ETHER ||
skb->inner_protocol != htons(ETH_P_TEB) ||
(skb_inner_mac_header(skb) - skb_transport_header(skb) !=
sizeof(struct udphdr) + sizeof(struct vxlanhdr)) ||
(skb->ip_summed != CHECKSUM_NONE &&
!can_checksum_protocol(features, inner_eth_hdr(skb)->h_proto))))
return features & ~(NETIF_F_CSUM_MASK | NETIF_F_GSO_MASK);
return features;
}
/* IP header + UDP + VXLAN + Ethernet header */
#define VXLAN_HEADROOM (20 + 8 + 8 + 14)
/* IPv6 header + UDP + VXLAN + Ethernet header */
#define VXLAN6_HEADROOM (40 + 8 + 8 + 14)
static inline struct vxlanhdr *vxlan_hdr(struct sk_buff *skb)
{
return (struct vxlanhdr *)(udp_hdr(skb) + 1);
}
static inline __be32 vxlan_vni(__be32 vni_field)
{
#if defined(__BIG_ENDIAN)
return (__force __be32)((__force u32)vni_field >> 8);
#else
return (__force __be32)((__force u32)(vni_field & VXLAN_VNI_MASK) << 8);
#endif
}
static inline __be32 vxlan_vni_field(__be32 vni)
{
#if defined(__BIG_ENDIAN)
return (__force __be32)((__force u32)vni << 8);
#else
return (__force __be32)((__force u32)vni >> 8);
#endif
}
static inline size_t vxlan_rco_start(__be32 vni_field)
{
return be32_to_cpu(vni_field & VXLAN_RCO_MASK) << VXLAN_RCO_SHIFT;
}
static inline size_t vxlan_rco_offset(__be32 vni_field)
{
return (vni_field & VXLAN_RCO_UDP) ?
offsetof(struct udphdr, check) :
offsetof(struct tcphdr, check);
}
static inline __be32 vxlan_compute_rco(unsigned int start, unsigned int offset)
{
__be32 vni_field = cpu_to_be32(start >> VXLAN_RCO_SHIFT);
if (offset == offsetof(struct udphdr, check))
vni_field |= VXLAN_RCO_UDP;
return vni_field;
}
static inline unsigned short vxlan_get_sk_family(struct vxlan_sock *vs)
{
return vs->sock->sk->sk_family;
}
#if IS_ENABLED(CONFIG_IPV6)
static inline bool vxlan_addr_any(const union vxlan_addr *ipa)
{
if (ipa->sa.sa_family == AF_INET6)
return ipv6_addr_any(&ipa->sin6.sin6_addr);
else
return ipa->sin.sin_addr.s_addr == htonl(INADDR_ANY);
}
static inline bool vxlan_addr_multicast(const union vxlan_addr *ipa)
{
if (ipa->sa.sa_family == AF_INET6)
return ipv6_addr_is_multicast(&ipa->sin6.sin6_addr);
else
return IN_MULTICAST(ntohl(ipa->sin.sin_addr.s_addr));
}
#else /* !IS_ENABLED(CONFIG_IPV6) */
static inline bool vxlan_addr_any(const union vxlan_addr *ipa)
{
return ipa->sin.sin_addr.s_addr == htonl(INADDR_ANY);
}
static inline bool vxlan_addr_multicast(const union vxlan_addr *ipa)
{
return IN_MULTICAST(ntohl(ipa->sin.sin_addr.s_addr));
}
#endif /* IS_ENABLED(CONFIG_IPV6) */
static inline bool netif_is_vxlan(const struct net_device *dev)
{
return dev->rtnl_link_ops &&
!strcmp(dev->rtnl_link_ops->kind, "vxlan");
}
struct switchdev_notifier_vxlan_fdb_info {
struct switchdev_notifier_info info; /* must be first */
union vxlan_addr remote_ip;
__be16 remote_port;
__be32 remote_vni;
u32 remote_ifindex;
u8 eth_addr[ETH_ALEN];
__be32 vni;
bool offloaded;
};
#if IS_ENABLED(CONFIG_VXLAN)
int vxlan_fdb_find_uc(struct net_device *dev, const u8 *mac, __be32 vni,
struct switchdev_notifier_vxlan_fdb_info *fdb_info);
#else
static inline int
vxlan_fdb_find_uc(struct net_device *dev, const u8 *mac, __be32 vni,
struct switchdev_notifier_vxlan_fdb_info *fdb_info)
{
return -ENOENT;
}
#endif
#endif
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