/* 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_helpers.h"
#include "test_iptunnel_common.h"
#include "bpf_endian.h"
int _version SEC("version") = 1;
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 bpf_map_def SEC("maps") vip_map = {
.type = BPF_MAP_TYPE_HASH,
.key_size = sizeof(struct vip),
.value_size = sizeof(struct vip_meta),
.max_entries = MAX_VIPS,
};
struct bpf_map_def SEC("maps") ch_rings = {
.type = BPF_MAP_TYPE_ARRAY,
.key_size = sizeof(__u32),
.value_size = sizeof(__u32),
.max_entries = CH_RINGS_SIZE,
};
struct bpf_map_def SEC("maps") reals = {
.type = BPF_MAP_TYPE_ARRAY,
.key_size = sizeof(__u32),
.value_size = sizeof(struct real_definition),
.max_entries = MAX_REALS,
};
struct bpf_map_def SEC("maps") stats = {
.type = BPF_MAP_TYPE_PERCPU_ARRAY,
.key_size = sizeof(__u32),
.value_size = sizeof(struct vip_stats),
.max_entries = MAX_VIPS,
};
struct bpf_map_def SEC("maps") ctl_array = {
.type = BPF_MAP_TYPE_ARRAY,
.key_size = sizeof(__u32),
.value_size = sizeof(struct ctl_value),
.max_entries = CTL_MAP_SIZE,
};
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";
