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![Stanislav Fomichev](/assets/img/avatar_default.png)
struct bpf_flow_dissector has a small subset of sk_buff fields that flow dissector BPF program is allowed to access and an optional pointer to real skb. Real skb is used only in bpf_skb_load_bytes helper to read non-linear data. The real motivation for this is to be able to call flow dissector from eth_get_headlen context where we don't have an skb and need to dissect raw bytes. Signed-off-by: Stanislav Fomichev <sdf@google.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
315 lines
8.1 KiB
C
315 lines
8.1 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _NET_FLOW_DISSECTOR_H
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#define _NET_FLOW_DISSECTOR_H
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#include <linux/types.h>
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#include <linux/in6.h>
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#include <uapi/linux/if_ether.h>
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/**
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* struct flow_dissector_key_control:
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* @thoff: Transport header offset
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*/
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struct flow_dissector_key_control {
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u16 thoff;
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u16 addr_type;
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u32 flags;
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};
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#define FLOW_DIS_IS_FRAGMENT BIT(0)
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#define FLOW_DIS_FIRST_FRAG BIT(1)
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#define FLOW_DIS_ENCAPSULATION BIT(2)
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enum flow_dissect_ret {
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FLOW_DISSECT_RET_OUT_GOOD,
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FLOW_DISSECT_RET_OUT_BAD,
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FLOW_DISSECT_RET_PROTO_AGAIN,
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FLOW_DISSECT_RET_IPPROTO_AGAIN,
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FLOW_DISSECT_RET_CONTINUE,
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};
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/**
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* struct flow_dissector_key_basic:
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* @thoff: Transport header offset
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* @n_proto: Network header protocol (eg. IPv4/IPv6)
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* @ip_proto: Transport header protocol (eg. TCP/UDP)
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*/
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struct flow_dissector_key_basic {
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__be16 n_proto;
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u8 ip_proto;
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u8 padding;
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};
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struct flow_dissector_key_tags {
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u32 flow_label;
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};
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struct flow_dissector_key_vlan {
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u16 vlan_id:12,
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vlan_priority:3;
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__be16 vlan_tpid;
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};
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struct flow_dissector_key_mpls {
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u32 mpls_ttl:8,
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mpls_bos:1,
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mpls_tc:3,
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mpls_label:20;
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};
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#define FLOW_DIS_TUN_OPTS_MAX 255
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/**
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* struct flow_dissector_key_enc_opts:
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* @data: tunnel option data
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* @len: length of tunnel option data
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* @dst_opt_type: tunnel option type
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*/
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struct flow_dissector_key_enc_opts {
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u8 data[FLOW_DIS_TUN_OPTS_MAX]; /* Using IP_TUNNEL_OPTS_MAX is desired
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* here but seems difficult to #include
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*/
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u8 len;
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__be16 dst_opt_type;
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};
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struct flow_dissector_key_keyid {
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__be32 keyid;
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};
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/**
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* struct flow_dissector_key_ipv4_addrs:
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* @src: source ip address
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* @dst: destination ip address
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*/
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struct flow_dissector_key_ipv4_addrs {
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/* (src,dst) must be grouped, in the same way than in IP header */
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__be32 src;
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__be32 dst;
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};
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/**
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* struct flow_dissector_key_ipv6_addrs:
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* @src: source ip address
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* @dst: destination ip address
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*/
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struct flow_dissector_key_ipv6_addrs {
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/* (src,dst) must be grouped, in the same way than in IP header */
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struct in6_addr src;
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struct in6_addr dst;
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};
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/**
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* struct flow_dissector_key_tipc:
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* @key: source node address combined with selector
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*/
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struct flow_dissector_key_tipc {
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__be32 key;
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};
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/**
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* struct flow_dissector_key_addrs:
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* @v4addrs: IPv4 addresses
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* @v6addrs: IPv6 addresses
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*/
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struct flow_dissector_key_addrs {
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union {
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struct flow_dissector_key_ipv4_addrs v4addrs;
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struct flow_dissector_key_ipv6_addrs v6addrs;
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struct flow_dissector_key_tipc tipckey;
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};
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};
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/**
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* flow_dissector_key_arp:
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* @ports: Operation, source and target addresses for an ARP header
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* for Ethernet hardware addresses and IPv4 protocol addresses
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* sip: Sender IP address
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* tip: Target IP address
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* op: Operation
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* sha: Sender hardware address
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* tpa: Target hardware address
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*/
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struct flow_dissector_key_arp {
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__u32 sip;
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__u32 tip;
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__u8 op;
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unsigned char sha[ETH_ALEN];
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unsigned char tha[ETH_ALEN];
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};
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/**
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* flow_dissector_key_tp_ports:
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* @ports: port numbers of Transport header
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* src: source port number
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* dst: destination port number
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*/
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struct flow_dissector_key_ports {
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union {
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__be32 ports;
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struct {
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__be16 src;
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__be16 dst;
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};
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};
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};
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/**
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* flow_dissector_key_icmp:
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* @ports: type and code of ICMP header
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* icmp: ICMP type (high) and code (low)
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* type: ICMP type
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* code: ICMP code
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*/
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struct flow_dissector_key_icmp {
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union {
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__be16 icmp;
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struct {
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u8 type;
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u8 code;
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};
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};
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};
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/**
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* struct flow_dissector_key_eth_addrs:
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* @src: source Ethernet address
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* @dst: destination Ethernet address
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*/
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struct flow_dissector_key_eth_addrs {
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/* (dst,src) must be grouped, in the same way than in ETH header */
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unsigned char dst[ETH_ALEN];
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unsigned char src[ETH_ALEN];
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};
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/**
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* struct flow_dissector_key_tcp:
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* @flags: flags
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*/
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struct flow_dissector_key_tcp {
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__be16 flags;
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};
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/**
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* struct flow_dissector_key_ip:
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* @tos: tos
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* @ttl: ttl
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*/
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struct flow_dissector_key_ip {
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__u8 tos;
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__u8 ttl;
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};
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enum flow_dissector_key_id {
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FLOW_DISSECTOR_KEY_CONTROL, /* struct flow_dissector_key_control */
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FLOW_DISSECTOR_KEY_BASIC, /* struct flow_dissector_key_basic */
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FLOW_DISSECTOR_KEY_IPV4_ADDRS, /* struct flow_dissector_key_ipv4_addrs */
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FLOW_DISSECTOR_KEY_IPV6_ADDRS, /* struct flow_dissector_key_ipv6_addrs */
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FLOW_DISSECTOR_KEY_PORTS, /* struct flow_dissector_key_ports */
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FLOW_DISSECTOR_KEY_ICMP, /* struct flow_dissector_key_icmp */
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FLOW_DISSECTOR_KEY_ETH_ADDRS, /* struct flow_dissector_key_eth_addrs */
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FLOW_DISSECTOR_KEY_TIPC, /* struct flow_dissector_key_tipc */
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FLOW_DISSECTOR_KEY_ARP, /* struct flow_dissector_key_arp */
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FLOW_DISSECTOR_KEY_VLAN, /* struct flow_dissector_key_vlan */
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FLOW_DISSECTOR_KEY_FLOW_LABEL, /* struct flow_dissector_key_tags */
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FLOW_DISSECTOR_KEY_GRE_KEYID, /* struct flow_dissector_key_keyid */
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FLOW_DISSECTOR_KEY_MPLS_ENTROPY, /* struct flow_dissector_key_keyid */
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FLOW_DISSECTOR_KEY_ENC_KEYID, /* struct flow_dissector_key_keyid */
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FLOW_DISSECTOR_KEY_ENC_IPV4_ADDRS, /* struct flow_dissector_key_ipv4_addrs */
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FLOW_DISSECTOR_KEY_ENC_IPV6_ADDRS, /* struct flow_dissector_key_ipv6_addrs */
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FLOW_DISSECTOR_KEY_ENC_CONTROL, /* struct flow_dissector_key_control */
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FLOW_DISSECTOR_KEY_ENC_PORTS, /* struct flow_dissector_key_ports */
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FLOW_DISSECTOR_KEY_MPLS, /* struct flow_dissector_key_mpls */
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FLOW_DISSECTOR_KEY_TCP, /* struct flow_dissector_key_tcp */
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FLOW_DISSECTOR_KEY_IP, /* struct flow_dissector_key_ip */
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FLOW_DISSECTOR_KEY_CVLAN, /* struct flow_dissector_key_vlan */
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FLOW_DISSECTOR_KEY_ENC_IP, /* struct flow_dissector_key_ip */
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FLOW_DISSECTOR_KEY_ENC_OPTS, /* struct flow_dissector_key_enc_opts */
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FLOW_DISSECTOR_KEY_MAX,
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};
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#define FLOW_DISSECTOR_F_PARSE_1ST_FRAG BIT(0)
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#define FLOW_DISSECTOR_F_STOP_AT_L3 BIT(1)
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#define FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL BIT(2)
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#define FLOW_DISSECTOR_F_STOP_AT_ENCAP BIT(3)
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struct flow_dissector_key {
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enum flow_dissector_key_id key_id;
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size_t offset; /* offset of struct flow_dissector_key_*
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in target the struct */
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};
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struct flow_dissector {
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unsigned int used_keys; /* each bit repesents presence of one key id */
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unsigned short int offset[FLOW_DISSECTOR_KEY_MAX];
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};
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struct flow_keys_basic {
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struct flow_dissector_key_control control;
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struct flow_dissector_key_basic basic;
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};
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struct flow_keys {
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struct flow_dissector_key_control control;
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#define FLOW_KEYS_HASH_START_FIELD basic
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struct flow_dissector_key_basic basic;
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struct flow_dissector_key_tags tags;
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struct flow_dissector_key_vlan vlan;
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struct flow_dissector_key_vlan cvlan;
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struct flow_dissector_key_keyid keyid;
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struct flow_dissector_key_ports ports;
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struct flow_dissector_key_addrs addrs;
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};
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#define FLOW_KEYS_HASH_OFFSET \
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offsetof(struct flow_keys, FLOW_KEYS_HASH_START_FIELD)
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__be32 flow_get_u32_src(const struct flow_keys *flow);
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__be32 flow_get_u32_dst(const struct flow_keys *flow);
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extern struct flow_dissector flow_keys_dissector;
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extern struct flow_dissector flow_keys_basic_dissector;
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/* struct flow_keys_digest:
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*
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* This structure is used to hold a digest of the full flow keys. This is a
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* larger "hash" of a flow to allow definitively matching specific flows where
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* the 32 bit skb->hash is not large enough. The size is limited to 16 bytes so
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* that it can be used in CB of skb (see sch_choke for an example).
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*/
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#define FLOW_KEYS_DIGEST_LEN 16
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struct flow_keys_digest {
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u8 data[FLOW_KEYS_DIGEST_LEN];
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};
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void make_flow_keys_digest(struct flow_keys_digest *digest,
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const struct flow_keys *flow);
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static inline bool flow_keys_have_l4(const struct flow_keys *keys)
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{
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return (keys->ports.ports || keys->tags.flow_label);
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}
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u32 flow_hash_from_keys(struct flow_keys *keys);
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static inline bool dissector_uses_key(const struct flow_dissector *flow_dissector,
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enum flow_dissector_key_id key_id)
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{
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return flow_dissector->used_keys & (1 << key_id);
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}
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static inline void *skb_flow_dissector_target(struct flow_dissector *flow_dissector,
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enum flow_dissector_key_id key_id,
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void *target_container)
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{
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return ((char *)target_container) + flow_dissector->offset[key_id];
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}
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struct bpf_flow_dissector {
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struct bpf_flow_keys *flow_keys;
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const struct sk_buff *skb;
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void *data;
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void *data_end;
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};
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#endif
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