| // SPDX-License-Identifier: GPL-2.0 |
| // Copyright (c) 2017 Facebook |
| #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 __always_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 __noinline 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 __noinline 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 __noinline 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 __noinline __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 __noinline 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); |
| __u32 key = RING_SIZE * vip_info->vip_num + hash % RING_SIZE; |
| __u32 *real_pos; |
| |
| if (hash != 0x358459b7 /* jhash of ipv4 packet */ && |
| hash != 0x2f4bc6bb /* jhash of ipv6 packet */) |
| return 0; |
| |
| 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 __noinline 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 __noinline 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 __noinline 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 __noinline 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 __noinline 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("tc") |
| 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"; |