472 lines
11 KiB
C
472 lines
11 KiB
C
/* Copyright (c) 2017 Facebook
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of version 2 of the GNU General Public
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* License as published by the Free Software Foundation.
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*/
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#include <stddef.h>
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#include <stdbool.h>
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#include <string.h>
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#include <linux/pkt_cls.h>
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#include <linux/bpf.h>
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#include <linux/in.h>
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#include <linux/if_ether.h>
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#include <linux/ip.h>
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#include <linux/ipv6.h>
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#include <linux/icmp.h>
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#include <linux/icmpv6.h>
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#include <linux/tcp.h>
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#include <linux/udp.h>
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#include <bpf/bpf_helpers.h>
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#include "test_iptunnel_common.h"
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#include <bpf/bpf_endian.h>
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static inline __u32 rol32(__u32 word, unsigned int shift)
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{
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return (word << shift) | (word >> ((-shift) & 31));
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}
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/* copy paste of jhash from kernel sources to make sure llvm
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* can compile it into valid sequence of bpf instructions
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*/
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#define __jhash_mix(a, b, c) \
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{ \
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a -= c; a ^= rol32(c, 4); c += b; \
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b -= a; b ^= rol32(a, 6); a += c; \
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c -= b; c ^= rol32(b, 8); b += a; \
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a -= c; a ^= rol32(c, 16); c += b; \
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b -= a; b ^= rol32(a, 19); a += c; \
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c -= b; c ^= rol32(b, 4); b += a; \
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}
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#define __jhash_final(a, b, c) \
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{ \
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c ^= b; c -= rol32(b, 14); \
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a ^= c; a -= rol32(c, 11); \
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b ^= a; b -= rol32(a, 25); \
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c ^= b; c -= rol32(b, 16); \
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a ^= c; a -= rol32(c, 4); \
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b ^= a; b -= rol32(a, 14); \
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c ^= b; c -= rol32(b, 24); \
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}
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#define JHASH_INITVAL 0xdeadbeef
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typedef unsigned int u32;
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static inline u32 jhash(const void *key, u32 length, u32 initval)
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{
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u32 a, b, c;
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const unsigned char *k = key;
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a = b = c = JHASH_INITVAL + length + initval;
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while (length > 12) {
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a += *(u32 *)(k);
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b += *(u32 *)(k + 4);
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c += *(u32 *)(k + 8);
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__jhash_mix(a, b, c);
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length -= 12;
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k += 12;
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}
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switch (length) {
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case 12: c += (u32)k[11]<<24;
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case 11: c += (u32)k[10]<<16;
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case 10: c += (u32)k[9]<<8;
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case 9: c += k[8];
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case 8: b += (u32)k[7]<<24;
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case 7: b += (u32)k[6]<<16;
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case 6: b += (u32)k[5]<<8;
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case 5: b += k[4];
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case 4: a += (u32)k[3]<<24;
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case 3: a += (u32)k[2]<<16;
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case 2: a += (u32)k[1]<<8;
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case 1: a += k[0];
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__jhash_final(a, b, c);
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case 0: /* Nothing left to add */
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break;
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}
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return c;
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}
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static inline u32 __jhash_nwords(u32 a, u32 b, u32 c, u32 initval)
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{
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a += initval;
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b += initval;
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c += initval;
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__jhash_final(a, b, c);
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return c;
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}
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static inline u32 jhash_2words(u32 a, u32 b, u32 initval)
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{
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return __jhash_nwords(a, b, 0, initval + JHASH_INITVAL + (2 << 2));
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}
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#define PCKT_FRAGMENTED 65343
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#define IPV4_HDR_LEN_NO_OPT 20
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#define IPV4_PLUS_ICMP_HDR 28
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#define IPV6_PLUS_ICMP_HDR 48
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#define RING_SIZE 2
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#define MAX_VIPS 12
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#define MAX_REALS 5
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#define CTL_MAP_SIZE 16
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#define CH_RINGS_SIZE (MAX_VIPS * RING_SIZE)
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#define F_IPV6 (1 << 0)
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#define F_HASH_NO_SRC_PORT (1 << 0)
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#define F_ICMP (1 << 0)
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#define F_SYN_SET (1 << 1)
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struct packet_description {
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union {
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__be32 src;
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__be32 srcv6[4];
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};
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union {
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__be32 dst;
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__be32 dstv6[4];
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};
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union {
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__u32 ports;
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__u16 port16[2];
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};
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__u8 proto;
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__u8 flags;
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};
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struct ctl_value {
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union {
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__u64 value;
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__u32 ifindex;
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__u8 mac[6];
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};
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};
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struct vip_meta {
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__u32 flags;
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__u32 vip_num;
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};
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struct real_definition {
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union {
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__be32 dst;
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__be32 dstv6[4];
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};
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__u8 flags;
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};
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struct vip_stats {
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__u64 bytes;
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__u64 pkts;
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};
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struct eth_hdr {
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unsigned char eth_dest[ETH_ALEN];
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unsigned char eth_source[ETH_ALEN];
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unsigned short eth_proto;
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};
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struct {
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__uint(type, BPF_MAP_TYPE_HASH);
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__uint(max_entries, MAX_VIPS);
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__type(key, struct vip);
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__type(value, struct vip_meta);
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} vip_map SEC(".maps");
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struct {
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__uint(type, BPF_MAP_TYPE_ARRAY);
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__uint(max_entries, CH_RINGS_SIZE);
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__type(key, __u32);
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__type(value, __u32);
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} ch_rings SEC(".maps");
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struct {
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__uint(type, BPF_MAP_TYPE_ARRAY);
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__uint(max_entries, MAX_REALS);
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__type(key, __u32);
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__type(value, struct real_definition);
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} reals SEC(".maps");
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struct {
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__uint(type, BPF_MAP_TYPE_PERCPU_ARRAY);
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__uint(max_entries, MAX_VIPS);
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__type(key, __u32);
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__type(value, struct vip_stats);
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} stats SEC(".maps");
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struct {
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__uint(type, BPF_MAP_TYPE_ARRAY);
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__uint(max_entries, CTL_MAP_SIZE);
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__type(key, __u32);
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__type(value, struct ctl_value);
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} ctl_array SEC(".maps");
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static __always_inline __u32 get_packet_hash(struct packet_description *pckt,
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bool ipv6)
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{
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if (ipv6)
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return jhash_2words(jhash(pckt->srcv6, 16, MAX_VIPS),
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pckt->ports, CH_RINGS_SIZE);
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else
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return jhash_2words(pckt->src, pckt->ports, CH_RINGS_SIZE);
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}
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static __always_inline bool get_packet_dst(struct real_definition **real,
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struct packet_description *pckt,
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struct vip_meta *vip_info,
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bool is_ipv6)
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{
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__u32 hash = get_packet_hash(pckt, is_ipv6) % RING_SIZE;
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__u32 key = RING_SIZE * vip_info->vip_num + hash;
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__u32 *real_pos;
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real_pos = bpf_map_lookup_elem(&ch_rings, &key);
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if (!real_pos)
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return false;
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key = *real_pos;
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*real = bpf_map_lookup_elem(&reals, &key);
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if (!(*real))
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return false;
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return true;
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}
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static __always_inline int parse_icmpv6(void *data, void *data_end, __u64 off,
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struct packet_description *pckt)
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{
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struct icmp6hdr *icmp_hdr;
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struct ipv6hdr *ip6h;
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icmp_hdr = data + off;
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if (icmp_hdr + 1 > data_end)
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return TC_ACT_SHOT;
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if (icmp_hdr->icmp6_type != ICMPV6_PKT_TOOBIG)
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return TC_ACT_OK;
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off += sizeof(struct icmp6hdr);
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ip6h = data + off;
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if (ip6h + 1 > data_end)
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return TC_ACT_SHOT;
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pckt->proto = ip6h->nexthdr;
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pckt->flags |= F_ICMP;
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memcpy(pckt->srcv6, ip6h->daddr.s6_addr32, 16);
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memcpy(pckt->dstv6, ip6h->saddr.s6_addr32, 16);
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return TC_ACT_UNSPEC;
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}
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static __always_inline int parse_icmp(void *data, void *data_end, __u64 off,
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struct packet_description *pckt)
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{
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struct icmphdr *icmp_hdr;
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struct iphdr *iph;
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icmp_hdr = data + off;
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if (icmp_hdr + 1 > data_end)
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return TC_ACT_SHOT;
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if (icmp_hdr->type != ICMP_DEST_UNREACH ||
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icmp_hdr->code != ICMP_FRAG_NEEDED)
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return TC_ACT_OK;
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off += sizeof(struct icmphdr);
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iph = data + off;
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if (iph + 1 > data_end)
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return TC_ACT_SHOT;
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if (iph->ihl != 5)
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return TC_ACT_SHOT;
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pckt->proto = iph->protocol;
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pckt->flags |= F_ICMP;
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pckt->src = iph->daddr;
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pckt->dst = iph->saddr;
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return TC_ACT_UNSPEC;
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}
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static __always_inline bool parse_udp(void *data, __u64 off, void *data_end,
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struct packet_description *pckt)
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{
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struct udphdr *udp;
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udp = data + off;
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if (udp + 1 > data_end)
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return false;
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if (!(pckt->flags & F_ICMP)) {
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pckt->port16[0] = udp->source;
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pckt->port16[1] = udp->dest;
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} else {
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pckt->port16[0] = udp->dest;
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pckt->port16[1] = udp->source;
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}
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return true;
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}
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static __always_inline bool parse_tcp(void *data, __u64 off, void *data_end,
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struct packet_description *pckt)
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{
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struct tcphdr *tcp;
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tcp = data + off;
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if (tcp + 1 > data_end)
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return false;
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if (tcp->syn)
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pckt->flags |= F_SYN_SET;
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if (!(pckt->flags & F_ICMP)) {
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pckt->port16[0] = tcp->source;
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pckt->port16[1] = tcp->dest;
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} else {
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pckt->port16[0] = tcp->dest;
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pckt->port16[1] = tcp->source;
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}
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return true;
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}
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static __always_inline int process_packet(void *data, __u64 off, void *data_end,
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bool is_ipv6, struct __sk_buff *skb)
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{
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void *pkt_start = (void *)(long)skb->data;
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struct packet_description pckt = {};
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struct eth_hdr *eth = pkt_start;
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struct bpf_tunnel_key tkey = {};
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struct vip_stats *data_stats;
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struct real_definition *dst;
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struct vip_meta *vip_info;
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struct ctl_value *cval;
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__u32 v4_intf_pos = 1;
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__u32 v6_intf_pos = 2;
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struct ipv6hdr *ip6h;
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struct vip vip = {};
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struct iphdr *iph;
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int tun_flag = 0;
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__u16 pkt_bytes;
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__u64 iph_len;
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__u32 ifindex;
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__u8 protocol;
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__u32 vip_num;
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int action;
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tkey.tunnel_ttl = 64;
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if (is_ipv6) {
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ip6h = data + off;
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if (ip6h + 1 > data_end)
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return TC_ACT_SHOT;
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iph_len = sizeof(struct ipv6hdr);
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protocol = ip6h->nexthdr;
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pckt.proto = protocol;
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pkt_bytes = bpf_ntohs(ip6h->payload_len);
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off += iph_len;
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if (protocol == IPPROTO_FRAGMENT) {
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return TC_ACT_SHOT;
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} else if (protocol == IPPROTO_ICMPV6) {
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action = parse_icmpv6(data, data_end, off, &pckt);
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if (action >= 0)
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return action;
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off += IPV6_PLUS_ICMP_HDR;
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} else {
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memcpy(pckt.srcv6, ip6h->saddr.s6_addr32, 16);
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memcpy(pckt.dstv6, ip6h->daddr.s6_addr32, 16);
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}
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} else {
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iph = data + off;
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if (iph + 1 > data_end)
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return TC_ACT_SHOT;
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if (iph->ihl != 5)
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return TC_ACT_SHOT;
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protocol = iph->protocol;
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pckt.proto = protocol;
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pkt_bytes = bpf_ntohs(iph->tot_len);
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off += IPV4_HDR_LEN_NO_OPT;
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if (iph->frag_off & PCKT_FRAGMENTED)
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return TC_ACT_SHOT;
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if (protocol == IPPROTO_ICMP) {
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action = parse_icmp(data, data_end, off, &pckt);
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if (action >= 0)
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return action;
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off += IPV4_PLUS_ICMP_HDR;
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} else {
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pckt.src = iph->saddr;
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pckt.dst = iph->daddr;
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}
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}
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protocol = pckt.proto;
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if (protocol == IPPROTO_TCP) {
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if (!parse_tcp(data, off, data_end, &pckt))
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return TC_ACT_SHOT;
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} else if (protocol == IPPROTO_UDP) {
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if (!parse_udp(data, off, data_end, &pckt))
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return TC_ACT_SHOT;
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} else {
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return TC_ACT_SHOT;
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}
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if (is_ipv6)
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memcpy(vip.daddr.v6, pckt.dstv6, 16);
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else
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vip.daddr.v4 = pckt.dst;
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vip.dport = pckt.port16[1];
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vip.protocol = pckt.proto;
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vip_info = bpf_map_lookup_elem(&vip_map, &vip);
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if (!vip_info) {
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vip.dport = 0;
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vip_info = bpf_map_lookup_elem(&vip_map, &vip);
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if (!vip_info)
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return TC_ACT_SHOT;
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pckt.port16[1] = 0;
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}
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if (vip_info->flags & F_HASH_NO_SRC_PORT)
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pckt.port16[0] = 0;
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if (!get_packet_dst(&dst, &pckt, vip_info, is_ipv6))
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return TC_ACT_SHOT;
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if (dst->flags & F_IPV6) {
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cval = bpf_map_lookup_elem(&ctl_array, &v6_intf_pos);
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if (!cval)
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return TC_ACT_SHOT;
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ifindex = cval->ifindex;
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memcpy(tkey.remote_ipv6, dst->dstv6, 16);
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tun_flag = BPF_F_TUNINFO_IPV6;
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} else {
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cval = bpf_map_lookup_elem(&ctl_array, &v4_intf_pos);
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if (!cval)
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return TC_ACT_SHOT;
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ifindex = cval->ifindex;
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tkey.remote_ipv4 = dst->dst;
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}
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vip_num = vip_info->vip_num;
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data_stats = bpf_map_lookup_elem(&stats, &vip_num);
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if (!data_stats)
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return TC_ACT_SHOT;
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data_stats->pkts++;
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data_stats->bytes += pkt_bytes;
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bpf_skb_set_tunnel_key(skb, &tkey, sizeof(tkey), tun_flag);
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*(u32 *)eth->eth_dest = tkey.remote_ipv4;
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return bpf_redirect(ifindex, 0);
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}
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SEC("tc")
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int balancer_ingress(struct __sk_buff *ctx)
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{
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void *data_end = (void *)(long)ctx->data_end;
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void *data = (void *)(long)ctx->data;
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struct eth_hdr *eth = data;
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__u32 eth_proto;
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__u32 nh_off;
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nh_off = sizeof(struct eth_hdr);
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if (data + nh_off > data_end)
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return TC_ACT_SHOT;
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eth_proto = eth->eth_proto;
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if (eth_proto == bpf_htons(ETH_P_IP))
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return process_packet(data, nh_off, data_end, false, ctx);
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else if (eth_proto == bpf_htons(ETH_P_IPV6))
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return process_packet(data, nh_off, data_end, true, ctx);
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else
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return TC_ACT_SHOT;
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}
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char _license[] SEC("license") = "GPL";
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