tools/testing/selftests/bpf/progs/test_l4lb.c - linux/kernel/git/bpf/bpf-next - Git at Google

 /* Copyright (c) 2017 Facebook
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of version 2 of the GNU General Public
  * License as published by the Free Software Foundation.
  */
 #include <stddef.h>
 #include <stdbool.h>
 #include <string.h>
 #include <linux/pkt_cls.h>
 #include <linux/bpf.h>
 #include <linux/in.h>
 #include <linux/if_ether.h>
 #include <linux/ip.h>
 #include <linux/ipv6.h>
 #include <linux/icmp.h>
 #include <linux/icmpv6.h>
 #include <linux/tcp.h>
 #include <linux/udp.h>
 #include <bpf/bpf_helpers.h>
 #include "test_iptunnel_common.h"
 #include <bpf/bpf_endian.h>

 static inline __u32 rol32(__u32 word, unsigned int shift)
 {
 	return (word << shift) | (word >> ((-shift) & 31));
 }

 /* copy paste of jhash from kernel sources to make sure llvm
  * can compile it into valid sequence of bpf instructions
  */
 #define __jhash_mix(a, b, c)			\
 {						\
 	a -= c;  a ^= rol32(c, 4);  c += b;	\
 	b -= a;  b ^= rol32(a, 6);  a += c;	\
 	c -= b;  c ^= rol32(b, 8);  b += a;	\
 	a -= c;  a ^= rol32(c, 16); c += b;	\
 	b -= a;  b ^= rol32(a, 19); a += c;	\
 	c -= b;  c ^= rol32(b, 4);  b += a;	\
 }

 #define __jhash_final(a, b, c)			\
 {						\
 	c ^= b; c -= rol32(b, 14);		\
 	a ^= c; a -= rol32(c, 11);		\
 	b ^= a; b -= rol32(a, 25);		\
 	c ^= b; c -= rol32(b, 16);		\
 	a ^= c; a -= rol32(c, 4);		\
 	b ^= a; b -= rol32(a, 14);		\
 	c ^= b; c -= rol32(b, 24);		\
 }

 #define JHASH_INITVAL		0xdeadbeef

 typedef unsigned int u32;

 static inline u32 jhash(const void *key, u32 length, u32 initval)
 {
 	u32 a, b, c;
 	const unsigned char *k = key;

 	a = b = c = JHASH_INITVAL + length + initval;

 	while (length > 12) {
 		a += *(u32 *)(k);
 		b += *(u32 *)(k + 4);
 		c += *(u32 *)(k + 8);
 		__jhash_mix(a, b, c);
 		length -= 12;
 		k += 12;
 	}
 	switch (length) {
 	case 12: c += (u32)k[11]<<24;
 	case 11: c += (u32)k[10]<<16;
 	case 10: c += (u32)k[9]<<8;
 	case 9:  c += k[8];
 	case 8:  b += (u32)k[7]<<24;
 	case 7:  b += (u32)k[6]<<16;
 	case 6:  b += (u32)k[5]<<8;
 	case 5:  b += k[4];
 	case 4:  a += (u32)k[3]<<24;
 	case 3:  a += (u32)k[2]<<16;
 	case 2:  a += (u32)k[1]<<8;
 	case 1:  a += k[0];
 		 __jhash_final(a, b, c);
 	case 0: /* Nothing left to add */
 		break;
 	}

 	return c;
 }

 static inline u32 __jhash_nwords(u32 a, u32 b, u32 c, u32 initval)
 {
 	a += initval;
 	b += initval;
 	c += initval;
 	__jhash_final(a, b, c);
 	return c;
 }

 static inline u32 jhash_2words(u32 a, u32 b, u32 initval)
 {
 	return __jhash_nwords(a, b, 0, initval + JHASH_INITVAL + (2 << 2));
 }

 #define PCKT_FRAGMENTED 65343
 #define IPV4_HDR_LEN_NO_OPT 20
 #define IPV4_PLUS_ICMP_HDR 28
 #define IPV6_PLUS_ICMP_HDR 48
 #define RING_SIZE 2
 #define MAX_VIPS 12
 #define MAX_REALS 5
 #define CTL_MAP_SIZE 16
 #define CH_RINGS_SIZE (MAX_VIPS * RING_SIZE)
 #define F_IPV6 (1 << 0)
 #define F_HASH_NO_SRC_PORT (1 << 0)
 #define F_ICMP (1 << 0)
 #define F_SYN_SET (1 << 1)

 struct packet_description {
 	union {
 		__be32 src;
 		__be32 srcv6[4];
 	};
 	union {
 		__be32 dst;
 		__be32 dstv6[4];
 	};
 	union {
 		__u32 ports;
 		__u16 port16[2];
 	};
 	__u8 proto;
 	__u8 flags;
 };

 struct ctl_value {
 	union {
 		__u64 value;
 		__u32 ifindex;
 		__u8 mac[6];
 	};
 };

 struct vip_meta {
 	__u32 flags;
 	__u32 vip_num;
 };

 struct real_definition {
 	union {
 		__be32 dst;
 		__be32 dstv6[4];
 	};
 	__u8 flags;
 };

 struct vip_stats {
 	__u64 bytes;
 	__u64 pkts;
 };

 struct eth_hdr {
 	unsigned char eth_dest[ETH_ALEN];
 	unsigned char eth_source[ETH_ALEN];
 	unsigned short eth_proto;
 };

 struct {
 	__uint(type, BPF_MAP_TYPE_HASH);
 	__uint(max_entries, MAX_VIPS);
 	__type(key, struct vip);
 	__type(value, struct vip_meta);
 } vip_map SEC(".maps");

 struct {
 	__uint(type, BPF_MAP_TYPE_ARRAY);
 	__uint(max_entries, CH_RINGS_SIZE);
 	__type(key, __u32);
 	__type(value, __u32);
 } ch_rings SEC(".maps");

 struct {
 	__uint(type, BPF_MAP_TYPE_ARRAY);
 	__uint(max_entries, MAX_REALS);
 	__type(key, __u32);
 	__type(value, struct real_definition);
 } reals SEC(".maps");

 struct {
 	__uint(type, BPF_MAP_TYPE_PERCPU_ARRAY);
 	__uint(max_entries, MAX_VIPS);
 	__type(key, __u32);
 	__type(value, struct vip_stats);
 } stats SEC(".maps");

 struct {
 	__uint(type, BPF_MAP_TYPE_ARRAY);
 	__uint(max_entries, CTL_MAP_SIZE);
 	__type(key, __u32);
 	__type(value, struct ctl_value);
 } ctl_array SEC(".maps");

 static __always_inline __u32 get_packet_hash(struct packet_description *pckt,
 					     bool ipv6)
 {
 	if (ipv6)
 		return jhash_2words(jhash(pckt->srcv6, 16, MAX_VIPS),
 				    pckt->ports, CH_RINGS_SIZE);
 	else
 		return jhash_2words(pckt->src, pckt->ports, CH_RINGS_SIZE);
 }

 static __always_inline bool get_packet_dst(struct real_definition **real,
 					   struct packet_description *pckt,
 					   struct vip_meta *vip_info,
 					   bool is_ipv6)
 {
 	__u32 hash = get_packet_hash(pckt, is_ipv6) % RING_SIZE;
 	__u32 key = RING_SIZE * vip_info->vip_num + hash;
 	__u32 *real_pos;

 	real_pos = bpf_map_lookup_elem(&ch_rings, &key);
 	if (!real_pos)
 		return false;
 	key = *real_pos;
 	*real = bpf_map_lookup_elem(&reals, &key);
 	if (!(*real))
 		return false;
 	return true;
 }

 static __always_inline int parse_icmpv6(void *data, void *data_end, __u64 off,
 					struct packet_description *pckt)
 {
 	struct icmp6hdr *icmp_hdr;
 	struct ipv6hdr *ip6h;

 	icmp_hdr = data + off;
 	if (icmp_hdr + 1 > data_end)
 		return TC_ACT_SHOT;
 	if (icmp_hdr->icmp6_type != ICMPV6_PKT_TOOBIG)
 		return TC_ACT_OK;
 	off += sizeof(struct icmp6hdr);
 	ip6h = data + off;
 	if (ip6h + 1 > data_end)
 		return TC_ACT_SHOT;
 	pckt->proto = ip6h->nexthdr;
 	pckt->flags |= F_ICMP;
 	memcpy(pckt->srcv6, ip6h->daddr.s6_addr32, 16);
 	memcpy(pckt->dstv6, ip6h->saddr.s6_addr32, 16);
 	return TC_ACT_UNSPEC;
 }

 static __always_inline int parse_icmp(void *data, void *data_end, __u64 off,
 				      struct packet_description *pckt)
 {
 	struct icmphdr *icmp_hdr;
 	struct iphdr *iph;

 	icmp_hdr = data + off;
 	if (icmp_hdr + 1 > data_end)
 		return TC_ACT_SHOT;
 	if (icmp_hdr->type != ICMP_DEST_UNREACH ||
 	    icmp_hdr->code != ICMP_FRAG_NEEDED)
 		return TC_ACT_OK;
 	off += sizeof(struct icmphdr);
 	iph = data + off;
 	if (iph + 1 > data_end)
 		return TC_ACT_SHOT;
 	if (iph->ihl != 5)
 		return TC_ACT_SHOT;
 	pckt->proto = iph->protocol;
 	pckt->flags |= F_ICMP;
 	pckt->src = iph->daddr;
 	pckt->dst = iph->saddr;
 	return TC_ACT_UNSPEC;
 }

 static __always_inline bool parse_udp(void *data, __u64 off, void *data_end,
 				      struct packet_description *pckt)
 {
 	struct udphdr *udp;
 	udp = data + off;

 	if (udp + 1 > data_end)
 		return false;

 	if (!(pckt->flags & F_ICMP)) {
 		pckt->port16[0] = udp->source;
 		pckt->port16[1] = udp->dest;
 	} else {
 		pckt->port16[0] = udp->dest;
 		pckt->port16[1] = udp->source;
 	}
 	return true;
 }

 static __always_inline bool parse_tcp(void *data, __u64 off, void *data_end,
 				      struct packet_description *pckt)
 {
 	struct tcphdr *tcp;

 	tcp = data + off;
 	if (tcp + 1 > data_end)
 		return false;

 	if (tcp->syn)
 		pckt->flags |= F_SYN_SET;

 	if (!(pckt->flags & F_ICMP)) {
 		pckt->port16[0] = tcp->source;
 		pckt->port16[1] = tcp->dest;
 	} else {
 		pckt->port16[0] = tcp->dest;
 		pckt->port16[1] = tcp->source;
 	}
 	return true;
 }

 static __always_inline int process_packet(void *data, __u64 off, void *data_end,
 					  bool is_ipv6, struct __sk_buff *skb)
 {
 	void *pkt_start = (void *)(long)skb->data;
 	struct packet_description pckt = {};
 	struct eth_hdr *eth = pkt_start;
 	struct bpf_tunnel_key tkey = {};
 	struct vip_stats *data_stats;
 	struct real_definition *dst;
 	struct vip_meta *vip_info;
 	struct ctl_value *cval;
 	__u32 v4_intf_pos = 1;
 	__u32 v6_intf_pos = 2;
 	struct ipv6hdr *ip6h;
 	struct vip vip = {};
 	struct iphdr *iph;
 	int tun_flag = 0;
 	__u16 pkt_bytes;
 	__u64 iph_len;
 	__u32 ifindex;
 	__u8 protocol;
 	__u32 vip_num;
 	int action;

 	tkey.tunnel_ttl = 64;
 	if (is_ipv6) {
 		ip6h = data + off;
 		if (ip6h + 1 > data_end)
 			return TC_ACT_SHOT;

 		iph_len = sizeof(struct ipv6hdr);
 		protocol = ip6h->nexthdr;
 		pckt.proto = protocol;
 		pkt_bytes = bpf_ntohs(ip6h->payload_len);
 		off += iph_len;
 		if (protocol == IPPROTO_FRAGMENT) {
 			return TC_ACT_SHOT;
 		} else if (protocol == IPPROTO_ICMPV6) {
 			action = parse_icmpv6(data, data_end, off, &pckt);
 			if (action >= 0)
 				return action;
 			off += IPV6_PLUS_ICMP_HDR;
 		} else {
 			memcpy(pckt.srcv6, ip6h->saddr.s6_addr32, 16);
 			memcpy(pckt.dstv6, ip6h->daddr.s6_addr32, 16);
 		}
 	} else {
 		iph = data + off;
 		if (iph + 1 > data_end)
 			return TC_ACT_SHOT;
 		if (iph->ihl != 5)
 			return TC_ACT_SHOT;

 		protocol = iph->protocol;
 		pckt.proto = protocol;
 		pkt_bytes = bpf_ntohs(iph->tot_len);
 		off += IPV4_HDR_LEN_NO_OPT;

 		if (iph->frag_off & PCKT_FRAGMENTED)
 			return TC_ACT_SHOT;
 		if (protocol == IPPROTO_ICMP) {
 			action = parse_icmp(data, data_end, off, &pckt);
 			if (action >= 0)
 				return action;
 			off += IPV4_PLUS_ICMP_HDR;
 		} else {
 			pckt.src = iph->saddr;
 			pckt.dst = iph->daddr;
 		}
 	}
 	protocol = pckt.proto;

 	if (protocol == IPPROTO_TCP) {
 		if (!parse_tcp(data, off, data_end, &pckt))
 			return TC_ACT_SHOT;
 	} else if (protocol == IPPROTO_UDP) {
 		if (!parse_udp(data, off, data_end, &pckt))
 			return TC_ACT_SHOT;
 	} else {
 		return TC_ACT_SHOT;
 	}

 	if (is_ipv6)
 		memcpy(vip.daddr.v6, pckt.dstv6, 16);
 	else
 		vip.daddr.v4 = pckt.dst;

 	vip.dport = pckt.port16[1];
 	vip.protocol = pckt.proto;
 	vip_info = bpf_map_lookup_elem(&vip_map, &vip);
 	if (!vip_info) {
 		vip.dport = 0;
 		vip_info = bpf_map_lookup_elem(&vip_map, &vip);
 		if (!vip_info)
 			return TC_ACT_SHOT;
 		pckt.port16[1] = 0;
 	}

 	if (vip_info->flags & F_HASH_NO_SRC_PORT)
 		pckt.port16[0] = 0;

 	if (!get_packet_dst(&dst, &pckt, vip_info, is_ipv6))
 		return TC_ACT_SHOT;

 	if (dst->flags & F_IPV6) {
 		cval = bpf_map_lookup_elem(&ctl_array, &v6_intf_pos);
 		if (!cval)
 			return TC_ACT_SHOT;
 		ifindex = cval->ifindex;
 		memcpy(tkey.remote_ipv6, dst->dstv6, 16);
 		tun_flag = BPF_F_TUNINFO_IPV6;
 	} else {
 		cval = bpf_map_lookup_elem(&ctl_array, &v4_intf_pos);
 		if (!cval)
 			return TC_ACT_SHOT;
 		ifindex = cval->ifindex;
 		tkey.remote_ipv4 = dst->dst;
 	}
 	vip_num = vip_info->vip_num;
 	data_stats = bpf_map_lookup_elem(&stats, &vip_num);
 	if (!data_stats)
 		return TC_ACT_SHOT;
 	data_stats->pkts++;
 	data_stats->bytes += pkt_bytes;
 	bpf_skb_set_tunnel_key(skb, &tkey, sizeof(tkey), tun_flag);
 	*(u32 *)eth->eth_dest = tkey.remote_ipv4;
 	return bpf_redirect(ifindex, 0);
 }

 SEC("l4lb-demo")
 int balancer_ingress(struct __sk_buff *ctx)
 {
 	void *data_end = (void *)(long)ctx->data_end;
 	void *data = (void *)(long)ctx->data;
 	struct eth_hdr *eth = data;
 	__u32 eth_proto;
 	__u32 nh_off;

 	nh_off = sizeof(struct eth_hdr);
 	if (data + nh_off > data_end)
 		return TC_ACT_SHOT;
 	eth_proto = eth->eth_proto;
 	if (eth_proto == bpf_htons(ETH_P_IP))
 		return process_packet(data, nh_off, data_end, false, ctx);
 	else if (eth_proto == bpf_htons(ETH_P_IPV6))
 		return process_packet(data, nh_off, data_end, true, ctx);
 	else
 		return TC_ACT_SHOT;
 }
 char _license[] SEC("license") = "GPL";
	/* Copyright (c) 2017 Facebook
	*
	* This program is free software; you can redistribute it and/or
	* modify it under the terms of version 2 of the GNU General Public
	* License as published by the Free Software Foundation.
	*/
	#include <stddef.h>
	#include <stdbool.h>
	#include <string.h>
	#include <linux/pkt_cls.h>
	#include <linux/bpf.h>
	#include <linux/in.h>
	#include <linux/if_ether.h>
	#include <linux/ip.h>
	#include <linux/ipv6.h>
	#include <linux/icmp.h>
	#include <linux/icmpv6.h>
	#include <linux/tcp.h>
	#include <linux/udp.h>
	#include <bpf/bpf_helpers.h>
	#include "test_iptunnel_common.h"
	#include <bpf/bpf_endian.h>

	static inline __u32 rol32(__u32 word, unsigned int shift)
	{
	return (word << shift) \| (word >> ((-shift) & 31));
	}

	/* copy paste of jhash from kernel sources to make sure llvm
	* can compile it into valid sequence of bpf instructions
	*/
	#define __jhash_mix(a, b, c) \
	{ \
	a -= c; a ^= rol32(c, 4); c += b; \
	b -= a; b ^= rol32(a, 6); a += c; \
	c -= b; c ^= rol32(b, 8); b += a; \
	a -= c; a ^= rol32(c, 16); c += b; \
	b -= a; b ^= rol32(a, 19); a += c; \
	c -= b; c ^= rol32(b, 4); b += a; \
	}

	#define __jhash_final(a, b, c) \
	{ \
	c ^= b; c -= rol32(b, 14); \
	a ^= c; a -= rol32(c, 11); \
	b ^= a; b -= rol32(a, 25); \
	c ^= b; c -= rol32(b, 16); \
	a ^= c; a -= rol32(c, 4); \
	b ^= a; b -= rol32(a, 14); \
	c ^= b; c -= rol32(b, 24); \
	}

	#define JHASH_INITVAL 0xdeadbeef

	typedef unsigned int u32;

	static inline u32 jhash(const void *key, u32 length, u32 initval)
	{
	u32 a, b, c;
	const unsigned char *k = key;

	a = b = c = JHASH_INITVAL + length + initval;

	while (length > 12) {
	a += (u32 )(k);
	b += (u32 )(k + 4);
	c += (u32 )(k + 8);
	__jhash_mix(a, b, c);
	length -= 12;
	k += 12;
	}
	switch (length) {
	case 12: c += (u32)k[11]<<24;
	case 11: c += (u32)k[10]<<16;
	case 10: c += (u32)k[9]<<8;
	case 9: c += k[8];
	case 8: b += (u32)k[7]<<24;
	case 7: b += (u32)k[6]<<16;
	case 6: b += (u32)k[5]<<8;
	case 5: b += k[4];
	case 4: a += (u32)k[3]<<24;
	case 3: a += (u32)k[2]<<16;
	case 2: a += (u32)k[1]<<8;
	case 1: a += k[0];
	__jhash_final(a, b, c);
	case 0: /* Nothing left to add */
	break;
	}

	return c;
	}

	static inline u32 __jhash_nwords(u32 a, u32 b, u32 c, u32 initval)
	{
	a += initval;
	b += initval;
	c += initval;
	__jhash_final(a, b, c);
	return c;
	}

	static inline u32 jhash_2words(u32 a, u32 b, u32 initval)
	{
	return __jhash_nwords(a, b, 0, initval + JHASH_INITVAL + (2 << 2));
	}

	#define PCKT_FRAGMENTED 65343
	#define IPV4_HDR_LEN_NO_OPT 20
	#define IPV4_PLUS_ICMP_HDR 28
	#define IPV6_PLUS_ICMP_HDR 48
	#define RING_SIZE 2
	#define MAX_VIPS 12
	#define MAX_REALS 5
	#define CTL_MAP_SIZE 16
	#define CH_RINGS_SIZE (MAX_VIPS * RING_SIZE)
	#define F_IPV6 (1 << 0)
	#define F_HASH_NO_SRC_PORT (1 << 0)
	#define F_ICMP (1 << 0)
	#define F_SYN_SET (1 << 1)

	struct packet_description {
	union {
	__be32 src;
	__be32 srcv6[4];
	};
	union {
	__be32 dst;
	__be32 dstv6[4];
	};
	union {
	__u32 ports;
	__u16 port16[2];
	};
	__u8 proto;
	__u8 flags;
	};

	struct ctl_value {
	union {
	__u64 value;
	__u32 ifindex;
	__u8 mac[6];
	};
	};

	struct vip_meta {
	__u32 flags;
	__u32 vip_num;
	};

	struct real_definition {
	union {
	__be32 dst;
	__be32 dstv6[4];
	};
	__u8 flags;
	};

	struct vip_stats {
	__u64 bytes;
	__u64 pkts;
	};

	struct eth_hdr {
	unsigned char eth_dest[ETH_ALEN];
	unsigned char eth_source[ETH_ALEN];
	unsigned short eth_proto;
	};

	struct {
	__uint(type, BPF_MAP_TYPE_HASH);
	__uint(max_entries, MAX_VIPS);
	__type(key, struct vip);
	__type(value, struct vip_meta);
	} vip_map SEC(".maps");

	struct {
	__uint(type, BPF_MAP_TYPE_ARRAY);
	__uint(max_entries, CH_RINGS_SIZE);
	__type(key, __u32);
	__type(value, __u32);
	} ch_rings SEC(".maps");

	struct {
	__uint(type, BPF_MAP_TYPE_ARRAY);
	__uint(max_entries, MAX_REALS);
	__type(key, __u32);
	__type(value, struct real_definition);
	} reals SEC(".maps");

	struct {
	__uint(type, BPF_MAP_TYPE_PERCPU_ARRAY);
	__uint(max_entries, MAX_VIPS);
	__type(key, __u32);
	__type(value, struct vip_stats);
	} stats SEC(".maps");

	struct {
	__uint(type, BPF_MAP_TYPE_ARRAY);
	__uint(max_entries, CTL_MAP_SIZE);
	__type(key, __u32);
	__type(value, struct ctl_value);
	} ctl_array SEC(".maps");

	static __always_inline __u32 get_packet_hash(struct packet_description *pckt,
	bool ipv6)
	{
	if (ipv6)
	return jhash_2words(jhash(pckt->srcv6, 16, MAX_VIPS),
	pckt->ports, CH_RINGS_SIZE);
	else
	return jhash_2words(pckt->src, pckt->ports, CH_RINGS_SIZE);
	}

	static __always_inline bool get_packet_dst(struct real_definition **real,
	struct packet_description *pckt,
	struct vip_meta *vip_info,
	bool is_ipv6)
	{
	__u32 hash = get_packet_hash(pckt, is_ipv6) % RING_SIZE;
	__u32 key = RING_SIZE * vip_info->vip_num + hash;
	__u32 *real_pos;

	real_pos = bpf_map_lookup_elem(&ch_rings, &key);
	if (!real_pos)
	return false;
	key = *real_pos;
	*real = bpf_map_lookup_elem(&reals, &key);
	if (!(*real))
	return false;
	return true;
	}

	static __always_inline int parse_icmpv6(void data, void data_end, __u64 off,
	struct packet_description *pckt)
	{
	struct icmp6hdr *icmp_hdr;
	struct ipv6hdr *ip6h;

	icmp_hdr = data + off;
	if (icmp_hdr + 1 > data_end)
	return TC_ACT_SHOT;
	if (icmp_hdr->icmp6_type != ICMPV6_PKT_TOOBIG)
	return TC_ACT_OK;
	off += sizeof(struct icmp6hdr);
	ip6h = data + off;
	if (ip6h + 1 > data_end)
	return TC_ACT_SHOT;
	pckt->proto = ip6h->nexthdr;
	pckt->flags \|= F_ICMP;
	memcpy(pckt->srcv6, ip6h->daddr.s6_addr32, 16);
	memcpy(pckt->dstv6, ip6h->saddr.s6_addr32, 16);
	return TC_ACT_UNSPEC;
	}

	static __always_inline int parse_icmp(void data, void data_end, __u64 off,
	struct packet_description *pckt)
	{
	struct icmphdr *icmp_hdr;
	struct iphdr *iph;

	icmp_hdr = data + off;
	if (icmp_hdr + 1 > data_end)
	return TC_ACT_SHOT;
	if (icmp_hdr->type != ICMP_DEST_UNREACH \|\|
	icmp_hdr->code != ICMP_FRAG_NEEDED)
	return TC_ACT_OK;
	off += sizeof(struct icmphdr);
	iph = data + off;
	if (iph + 1 > data_end)
	return TC_ACT_SHOT;
	if (iph->ihl != 5)
	return TC_ACT_SHOT;
	pckt->proto = iph->protocol;
	pckt->flags \|= F_ICMP;
	pckt->src = iph->daddr;
	pckt->dst = iph->saddr;
	return TC_ACT_UNSPEC;
	}

	static __always_inline bool parse_udp(void data, __u64 off, void data_end,
	struct packet_description *pckt)
	{
	struct udphdr *udp;
	udp = data + off;

	if (udp + 1 > data_end)
	return false;

	if (!(pckt->flags & F_ICMP)) {
	pckt->port16[0] = udp->source;
	pckt->port16[1] = udp->dest;
	} else {
	pckt->port16[0] = udp->dest;
	pckt->port16[1] = udp->source;
	}
	return true;
	}

	static __always_inline bool parse_tcp(void data, __u64 off, void data_end,
	struct packet_description *pckt)
	{
	struct tcphdr *tcp;

	tcp = data + off;
	if (tcp + 1 > data_end)
	return false;

	if (tcp->syn)
	pckt->flags \|= F_SYN_SET;

	if (!(pckt->flags & F_ICMP)) {
	pckt->port16[0] = tcp->source;
	pckt->port16[1] = tcp->dest;
	} else {
	pckt->port16[0] = tcp->dest;
	pckt->port16[1] = tcp->source;
	}
	return true;
	}

	static __always_inline int process_packet(void data, __u64 off, void data_end,
	bool is_ipv6, struct __sk_buff *skb)
	{
	void pkt_start = (void )(long)skb->data;
	struct packet_description pckt = {};
	struct eth_hdr *eth = pkt_start;
	struct bpf_tunnel_key tkey = {};
	struct vip_stats *data_stats;
	struct real_definition *dst;
	struct vip_meta *vip_info;
	struct ctl_value *cval;
	__u32 v4_intf_pos = 1;
	__u32 v6_intf_pos = 2;
	struct ipv6hdr *ip6h;
	struct vip vip = {};
	struct iphdr *iph;
	int tun_flag = 0;
	__u16 pkt_bytes;
	__u64 iph_len;
	__u32 ifindex;
	__u8 protocol;
	__u32 vip_num;
	int action;

	tkey.tunnel_ttl = 64;
	if (is_ipv6) {
	ip6h = data + off;
	if (ip6h + 1 > data_end)
	return TC_ACT_SHOT;

	iph_len = sizeof(struct ipv6hdr);
	protocol = ip6h->nexthdr;
	pckt.proto = protocol;
	pkt_bytes = bpf_ntohs(ip6h->payload_len);
	off += iph_len;
	if (protocol == IPPROTO_FRAGMENT) {
	return TC_ACT_SHOT;
	} else if (protocol == IPPROTO_ICMPV6) {
	action = parse_icmpv6(data, data_end, off, &pckt);
	if (action >= 0)
	return action;
	off += IPV6_PLUS_ICMP_HDR;
	} else {
	memcpy(pckt.srcv6, ip6h->saddr.s6_addr32, 16);
	memcpy(pckt.dstv6, ip6h->daddr.s6_addr32, 16);
	}
	} else {
	iph = data + off;
	if (iph + 1 > data_end)
	return TC_ACT_SHOT;
	if (iph->ihl != 5)
	return TC_ACT_SHOT;

	protocol = iph->protocol;
	pckt.proto = protocol;
	pkt_bytes = bpf_ntohs(iph->tot_len);
	off += IPV4_HDR_LEN_NO_OPT;

	if (iph->frag_off & PCKT_FRAGMENTED)
	return TC_ACT_SHOT;
	if (protocol == IPPROTO_ICMP) {
	action = parse_icmp(data, data_end, off, &pckt);
	if (action >= 0)
	return action;
	off += IPV4_PLUS_ICMP_HDR;
	} else {
	pckt.src = iph->saddr;
	pckt.dst = iph->daddr;
	}
	}
	protocol = pckt.proto;

	if (protocol == IPPROTO_TCP) {
	if (!parse_tcp(data, off, data_end, &pckt))
	return TC_ACT_SHOT;
	} else if (protocol == IPPROTO_UDP) {
	if (!parse_udp(data, off, data_end, &pckt))
	return TC_ACT_SHOT;
	} else {
	return TC_ACT_SHOT;
	}

	if (is_ipv6)
	memcpy(vip.daddr.v6, pckt.dstv6, 16);
	else
	vip.daddr.v4 = pckt.dst;

	vip.dport = pckt.port16[1];
	vip.protocol = pckt.proto;
	vip_info = bpf_map_lookup_elem(&vip_map, &vip);
	if (!vip_info) {
	vip.dport = 0;
	vip_info = bpf_map_lookup_elem(&vip_map, &vip);
	if (!vip_info)
	return TC_ACT_SHOT;
	pckt.port16[1] = 0;
	}

	if (vip_info->flags & F_HASH_NO_SRC_PORT)
	pckt.port16[0] = 0;

	if (!get_packet_dst(&dst, &pckt, vip_info, is_ipv6))
	return TC_ACT_SHOT;

	if (dst->flags & F_IPV6) {
	cval = bpf_map_lookup_elem(&ctl_array, &v6_intf_pos);
	if (!cval)
	return TC_ACT_SHOT;
	ifindex = cval->ifindex;
	memcpy(tkey.remote_ipv6, dst->dstv6, 16);
	tun_flag = BPF_F_TUNINFO_IPV6;
	} else {
	cval = bpf_map_lookup_elem(&ctl_array, &v4_intf_pos);
	if (!cval)
	return TC_ACT_SHOT;
	ifindex = cval->ifindex;
	tkey.remote_ipv4 = dst->dst;
	}
	vip_num = vip_info->vip_num;
	data_stats = bpf_map_lookup_elem(&stats, &vip_num);
	if (!data_stats)
	return TC_ACT_SHOT;
	data_stats->pkts++;
	data_stats->bytes += pkt_bytes;
	bpf_skb_set_tunnel_key(skb, &tkey, sizeof(tkey), tun_flag);
	(u32 )eth->eth_dest = tkey.remote_ipv4;
	return bpf_redirect(ifindex, 0);
	}

	SEC("l4lb-demo")
	int balancer_ingress(struct __sk_buff *ctx)
	{
	void data_end = (void )(long)ctx->data_end;
	void data = (void )(long)ctx->data;
	struct eth_hdr *eth = data;
	__u32 eth_proto;
	__u32 nh_off;

	nh_off = sizeof(struct eth_hdr);
	if (data + nh_off > data_end)
	return TC_ACT_SHOT;
	eth_proto = eth->eth_proto;
	if (eth_proto == bpf_htons(ETH_P_IP))
	return process_packet(data, nh_off, data_end, false, ctx);
	else if (eth_proto == bpf_htons(ETH_P_IPV6))
	return process_packet(data, nh_off, data_end, true, ctx);
	else
	return TC_ACT_SHOT;
	}
	char _license[] SEC("license") = "GPL";