linux/include/net/flow_dissector.h
Tom Herbert 3a1214e8b0 flow_dissector: Cleanup control flow
__skb_flow_dissect is riddled with gotos that make discerning the flow,
debugging, and extending the capability difficult. This patch
reorganizes things so that we only perform goto's after the two main
switch statements (no gotos within the cases now). It also eliminates
several goto labels so that there are only two labels that can be target
for goto.

Reported-by: Alexander Popov <alex.popov@linux.com>
Signed-off-by: Tom Herbert <tom@quantonium.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-09-05 11:40:08 -07:00

284 lines
7.2 KiB
C

#ifndef _NET_FLOW_DISSECTOR_H
#define _NET_FLOW_DISSECTOR_H
#include <linux/types.h>
#include <linux/in6.h>
#include <uapi/linux/if_ether.h>
/**
* 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:
* @thoff: Transport header offset
* @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 {
u16 vlan_id:12,
vlan_priority:3;
u16 padding;
};
struct flow_dissector_key_mpls {
u32 mpls_ttl:8,
mpls_bos:1,
mpls_tc:3,
mpls_label:20;
};
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_addrs:
* @srcnode: source node address
*/
struct flow_dissector_key_tipc_addrs {
__be32 srcnode;
};
/**
* 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_addrs tipcaddrs;
};
};
/**
* 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:
* @ports: type and code of ICMP header
* icmp: ICMP type (high) and code (low)
* type: ICMP type
* code: ICMP code
*/
struct flow_dissector_key_icmp {
union {
__be16 icmp;
struct {
u8 type;
u8 code;
};
};
};
/**
* 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;
};
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_ICMP, /* struct flow_dissector_key_icmp */
FLOW_DISSECTOR_KEY_ETH_ADDRS, /* struct flow_dissector_key_eth_addrs */
FLOW_DISSECTOR_KEY_TIPC_ADDRS, /* struct flow_dissector_key_tipc_addrs */
FLOW_DISSECTOR_KEY_ARP, /* struct flow_dissector_key_arp */
FLOW_DISSECTOR_KEY_VLAN, /* struct flow_dissector_key_flow_vlan */
FLOW_DISSECTOR_KEY_FLOW_LABEL, /* struct flow_dissector_key_flow_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_MAX,
};
#define FLOW_DISSECTOR_F_PARSE_1ST_FRAG BIT(0)
#define FLOW_DISSECTOR_F_STOP_AT_L3 BIT(1)
#define FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL BIT(2)
#define FLOW_DISSECTOR_F_STOP_AT_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 {
struct flow_dissector_key_control control;
#define FLOW_KEYS_HASH_START_FIELD basic
struct flow_dissector_key_basic basic;
struct flow_dissector_key_tags tags;
struct flow_dissector_key_vlan vlan;
struct flow_dissector_key_keyid keyid;
struct flow_dissector_key_ports ports;
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_buf_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 by 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);
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];
}
#endif