linux/include/net/flow_dissector.h
Yoshiki Komachi 6de6e46d27 cls_flower: Fix inability to match GRE/IPIP packets
When a packet of a new flow arrives in openvswitch kernel module, it dissects
the packet and passes the extracted flow key to ovs-vswtichd daemon. If hw-
offload configuration is enabled, the daemon creates a new TC flower entry to
bypass openvswitch kernel module for the flow (TC flower can also offload flows
to NICs but this time that does not matter).

In this processing flow, I found the following issue in cases of GRE/IPIP
packets.

When ovs_flow_key_extract() in openvswitch module parses a packet of a new
GRE (or IPIP) flow received on non-tunneling vports, it extracts information
of the outer IP header for ip_proto/src_ip/dst_ip match keys.

This means ovs-vswitchd creates a TC flower entry with IP protocol/addresses
match keys whose values are those of the outer IP header. OTOH, TC flower,
which uses flow_dissector (different parser from openvswitch module), extracts
information of the inner IP header.

The following flow is an example to describe the issue in more detail.

   <----------- Outer IP -----------------> <---------- Inner IP ---------->
  +----------+--------------+--------------+----------+----------+----------+
  | ip_proto | src_ip       | dst_ip       | ip_proto | src_ip   | dst_ip   |
  | 47 (GRE) | 192.168.10.1 | 192.168.10.2 | 6 (TCP)  | 10.0.0.1 | 10.0.0.2 |
  +----------+--------------+--------------+----------+----------+----------+

In this case, TC flower entry and extracted information are shown as below:

  - ovs-vswitchd creates TC flower entry with:
      - ip_proto: 47
      - src_ip: 192.168.10.1
      - dst_ip: 192.168.10.2

  - TC flower extracts below for IP header matches:
      - ip_proto: 6
      - src_ip: 10.0.0.1
      - dst_ip: 10.0.0.2

Thus, GRE or IPIP packets never match the TC flower entry, as each
dissector behaves differently.

IMHO, the behavior of TC flower (flow dissector) does not look correct,
as ip_proto/src_ip/dst_ip in TC flower match means the outermost IP
header information except for GRE/IPIP cases. This patch adds a new
flow_dissector flag FLOW_DISSECTOR_F_STOP_BEFORE_ENCAP which skips
dissection of the encapsulated inner GRE/IPIP header in TC flower
classifier.

Signed-off-by: Yoshiki Komachi <komachi.yoshiki@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2021-10-29 14:03:22 +01:00

390 lines
9.9 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _NET_FLOW_DISSECTOR_H
#define _NET_FLOW_DISSECTOR_H
#include <linux/types.h>
#include <linux/in6.h>
#include <linux/siphash.h>
#include <linux/string.h>
#include <uapi/linux/if_ether.h>
struct bpf_prog;
struct net;
struct sk_buff;
/**
* struct flow_dissector_key_control:
* @thoff: Transport header offset
*/
struct flow_dissector_key_control {
u16 thoff;
u16 addr_type;
u32 flags;
};
#define FLOW_DIS_IS_FRAGMENT BIT(0)
#define FLOW_DIS_FIRST_FRAG BIT(1)
#define FLOW_DIS_ENCAPSULATION BIT(2)
enum flow_dissect_ret {
FLOW_DISSECT_RET_OUT_GOOD,
FLOW_DISSECT_RET_OUT_BAD,
FLOW_DISSECT_RET_PROTO_AGAIN,
FLOW_DISSECT_RET_IPPROTO_AGAIN,
FLOW_DISSECT_RET_CONTINUE,
};
/**
* struct flow_dissector_key_basic:
* @n_proto: Network header protocol (eg. IPv4/IPv6)
* @ip_proto: Transport header protocol (eg. TCP/UDP)
*/
struct flow_dissector_key_basic {
__be16 n_proto;
u8 ip_proto;
u8 padding;
};
struct flow_dissector_key_tags {
u32 flow_label;
};
struct flow_dissector_key_vlan {
union {
struct {
u16 vlan_id:12,
vlan_dei:1,
vlan_priority:3;
};
__be16 vlan_tci;
};
__be16 vlan_tpid;
};
struct flow_dissector_mpls_lse {
u32 mpls_ttl:8,
mpls_bos:1,
mpls_tc:3,
mpls_label:20;
};
#define FLOW_DIS_MPLS_MAX 7
struct flow_dissector_key_mpls {
struct flow_dissector_mpls_lse ls[FLOW_DIS_MPLS_MAX]; /* Label Stack */
u8 used_lses; /* One bit set for each Label Stack Entry in use */
};
static inline void dissector_set_mpls_lse(struct flow_dissector_key_mpls *mpls,
int lse_index)
{
mpls->used_lses |= 1 << lse_index;
}
#define FLOW_DIS_TUN_OPTS_MAX 255
/**
* struct flow_dissector_key_enc_opts:
* @data: tunnel option data
* @len: length of tunnel option data
* @dst_opt_type: tunnel option type
*/
struct flow_dissector_key_enc_opts {
u8 data[FLOW_DIS_TUN_OPTS_MAX]; /* Using IP_TUNNEL_OPTS_MAX is desired
* here but seems difficult to #include
*/
u8 len;
__be16 dst_opt_type;
};
struct flow_dissector_key_keyid {
__be32 keyid;
};
/**
* struct flow_dissector_key_ipv4_addrs:
* @src: source ip address
* @dst: destination ip address
*/
struct flow_dissector_key_ipv4_addrs {
/* (src,dst) must be grouped, in the same way than in IP header */
__be32 src;
__be32 dst;
};
/**
* struct flow_dissector_key_ipv6_addrs:
* @src: source ip address
* @dst: destination ip address
*/
struct flow_dissector_key_ipv6_addrs {
/* (src,dst) must be grouped, in the same way than in IP header */
struct in6_addr src;
struct in6_addr dst;
};
/**
* struct flow_dissector_key_tipc:
* @key: source node address combined with selector
*/
struct flow_dissector_key_tipc {
__be32 key;
};
/**
* struct flow_dissector_key_addrs:
* @v4addrs: IPv4 addresses
* @v6addrs: IPv6 addresses
*/
struct flow_dissector_key_addrs {
union {
struct flow_dissector_key_ipv4_addrs v4addrs;
struct flow_dissector_key_ipv6_addrs v6addrs;
struct flow_dissector_key_tipc tipckey;
};
};
/**
* flow_dissector_key_arp:
* @ports: Operation, source and target addresses for an ARP header
* for Ethernet hardware addresses and IPv4 protocol addresses
* sip: Sender IP address
* tip: Target IP address
* op: Operation
* sha: Sender hardware address
* tpa: Target hardware address
*/
struct flow_dissector_key_arp {
__u32 sip;
__u32 tip;
__u8 op;
unsigned char sha[ETH_ALEN];
unsigned char tha[ETH_ALEN];
};
/**
* flow_dissector_key_tp_ports:
* @ports: port numbers of Transport header
* src: source port number
* dst: destination port number
*/
struct flow_dissector_key_ports {
union {
__be32 ports;
struct {
__be16 src;
__be16 dst;
};
};
};
/**
* flow_dissector_key_icmp:
* type: ICMP type
* code: ICMP code
* id: session identifier
*/
struct flow_dissector_key_icmp {
struct {
u8 type;
u8 code;
};
u16 id;
};
/**
* struct flow_dissector_key_eth_addrs:
* @src: source Ethernet address
* @dst: destination Ethernet address
*/
struct flow_dissector_key_eth_addrs {
/* (dst,src) must be grouped, in the same way than in ETH header */
unsigned char dst[ETH_ALEN];
unsigned char src[ETH_ALEN];
};
/**
* struct flow_dissector_key_tcp:
* @flags: flags
*/
struct flow_dissector_key_tcp {
__be16 flags;
};
/**
* struct flow_dissector_key_ip:
* @tos: tos
* @ttl: ttl
*/
struct flow_dissector_key_ip {
__u8 tos;
__u8 ttl;
};
/**
* struct flow_dissector_key_meta:
* @ingress_ifindex: ingress ifindex
* @ingress_iftype: ingress interface type
*/
struct flow_dissector_key_meta {
int ingress_ifindex;
u16 ingress_iftype;
};
/**
* struct flow_dissector_key_ct:
* @ct_state: conntrack state after converting with map
* @ct_mark: conttrack mark
* @ct_zone: conntrack zone
* @ct_labels: conntrack labels
*/
struct flow_dissector_key_ct {
u16 ct_state;
u16 ct_zone;
u32 ct_mark;
u32 ct_labels[4];
};
/**
* struct flow_dissector_key_hash:
* @hash: hash value
*/
struct flow_dissector_key_hash {
u32 hash;
};
enum flow_dissector_key_id {
FLOW_DISSECTOR_KEY_CONTROL, /* struct flow_dissector_key_control */
FLOW_DISSECTOR_KEY_BASIC, /* struct flow_dissector_key_basic */
FLOW_DISSECTOR_KEY_IPV4_ADDRS, /* struct flow_dissector_key_ipv4_addrs */
FLOW_DISSECTOR_KEY_IPV6_ADDRS, /* struct flow_dissector_key_ipv6_addrs */
FLOW_DISSECTOR_KEY_PORTS, /* struct flow_dissector_key_ports */
FLOW_DISSECTOR_KEY_PORTS_RANGE, /* struct flow_dissector_key_ports */
FLOW_DISSECTOR_KEY_ICMP, /* struct flow_dissector_key_icmp */
FLOW_DISSECTOR_KEY_ETH_ADDRS, /* struct flow_dissector_key_eth_addrs */
FLOW_DISSECTOR_KEY_TIPC, /* struct flow_dissector_key_tipc */
FLOW_DISSECTOR_KEY_ARP, /* struct flow_dissector_key_arp */
FLOW_DISSECTOR_KEY_VLAN, /* struct flow_dissector_key_vlan */
FLOW_DISSECTOR_KEY_FLOW_LABEL, /* struct flow_dissector_key_tags */
FLOW_DISSECTOR_KEY_GRE_KEYID, /* struct flow_dissector_key_keyid */
FLOW_DISSECTOR_KEY_MPLS_ENTROPY, /* struct flow_dissector_key_keyid */
FLOW_DISSECTOR_KEY_ENC_KEYID, /* struct flow_dissector_key_keyid */
FLOW_DISSECTOR_KEY_ENC_IPV4_ADDRS, /* struct flow_dissector_key_ipv4_addrs */
FLOW_DISSECTOR_KEY_ENC_IPV6_ADDRS, /* struct flow_dissector_key_ipv6_addrs */
FLOW_DISSECTOR_KEY_ENC_CONTROL, /* struct flow_dissector_key_control */
FLOW_DISSECTOR_KEY_ENC_PORTS, /* struct flow_dissector_key_ports */
FLOW_DISSECTOR_KEY_MPLS, /* struct flow_dissector_key_mpls */
FLOW_DISSECTOR_KEY_TCP, /* struct flow_dissector_key_tcp */
FLOW_DISSECTOR_KEY_IP, /* struct flow_dissector_key_ip */
FLOW_DISSECTOR_KEY_CVLAN, /* struct flow_dissector_key_vlan */
FLOW_DISSECTOR_KEY_ENC_IP, /* struct flow_dissector_key_ip */
FLOW_DISSECTOR_KEY_ENC_OPTS, /* struct flow_dissector_key_enc_opts */
FLOW_DISSECTOR_KEY_META, /* struct flow_dissector_key_meta */
FLOW_DISSECTOR_KEY_CT, /* struct flow_dissector_key_ct */
FLOW_DISSECTOR_KEY_HASH, /* struct flow_dissector_key_hash */
FLOW_DISSECTOR_KEY_MAX,
};
#define FLOW_DISSECTOR_F_PARSE_1ST_FRAG BIT(0)
#define FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL BIT(1)
#define FLOW_DISSECTOR_F_STOP_AT_ENCAP BIT(2)
#define FLOW_DISSECTOR_F_STOP_BEFORE_ENCAP BIT(3)
struct flow_dissector_key {
enum flow_dissector_key_id key_id;
size_t offset; /* offset of struct flow_dissector_key_*
in target the struct */
};
struct flow_dissector {
unsigned int used_keys; /* each bit repesents presence of one key id */
unsigned short int offset[FLOW_DISSECTOR_KEY_MAX];
};
struct flow_keys_basic {
struct flow_dissector_key_control control;
struct flow_dissector_key_basic basic;
};
struct flow_keys {
struct flow_dissector_key_control control;
#define FLOW_KEYS_HASH_START_FIELD basic
struct flow_dissector_key_basic basic __aligned(SIPHASH_ALIGNMENT);
struct flow_dissector_key_tags tags;
struct flow_dissector_key_vlan vlan;
struct flow_dissector_key_vlan cvlan;
struct flow_dissector_key_keyid keyid;
struct flow_dissector_key_ports ports;
struct flow_dissector_key_icmp icmp;
/* 'addrs' must be the last member */
struct flow_dissector_key_addrs addrs;
};
#define FLOW_KEYS_HASH_OFFSET \
offsetof(struct flow_keys, FLOW_KEYS_HASH_START_FIELD)
__be32 flow_get_u32_src(const struct flow_keys *flow);
__be32 flow_get_u32_dst(const struct flow_keys *flow);
extern struct flow_dissector flow_keys_dissector;
extern struct flow_dissector flow_keys_basic_dissector;
/* struct flow_keys_digest:
*
* This structure is used to hold a digest of the full flow keys. This is a
* larger "hash" of a flow to allow definitively matching specific flows where
* the 32 bit skb->hash is not large enough. The size is limited to 16 bytes so
* that it can be used in CB of skb (see sch_choke for an example).
*/
#define FLOW_KEYS_DIGEST_LEN 16
struct flow_keys_digest {
u8 data[FLOW_KEYS_DIGEST_LEN];
};
void make_flow_keys_digest(struct flow_keys_digest *digest,
const struct flow_keys *flow);
static inline bool flow_keys_have_l4(const struct flow_keys *keys)
{
return (keys->ports.ports || keys->tags.flow_label);
}
u32 flow_hash_from_keys(struct flow_keys *keys);
void skb_flow_get_icmp_tci(const struct sk_buff *skb,
struct flow_dissector_key_icmp *key_icmp,
const void *data, int thoff, int hlen);
static inline bool dissector_uses_key(const struct flow_dissector *flow_dissector,
enum flow_dissector_key_id key_id)
{
return flow_dissector->used_keys & (1 << key_id);
}
static inline void *skb_flow_dissector_target(struct flow_dissector *flow_dissector,
enum flow_dissector_key_id key_id,
void *target_container)
{
return ((char *)target_container) + flow_dissector->offset[key_id];
}
struct bpf_flow_dissector {
struct bpf_flow_keys *flow_keys;
const struct sk_buff *skb;
const void *data;
const void *data_end;
};
static inline void
flow_dissector_init_keys(struct flow_dissector_key_control *key_control,
struct flow_dissector_key_basic *key_basic)
{
memset(key_control, 0, sizeof(*key_control));
memset(key_basic, 0, sizeof(*key_basic));
}
#ifdef CONFIG_BPF_SYSCALL
int flow_dissector_bpf_prog_attach_check(struct net *net,
struct bpf_prog *prog);
#endif /* CONFIG_BPF_SYSCALL */
#endif