1/* Copyright (c) 2016,2017 Facebook 2 * 3 * This program is free software; you can redistribute it and/or 4 * modify it under the terms of version 2 of the GNU General Public 5 * License as published by the Free Software Foundation. 6 */ 7#include <stddef.h> 8#include <string.h> 9#include <linux/bpf.h> 10#include <linux/if_ether.h> 11#include <linux/if_packet.h> 12#include <linux/ip.h> 13#include <linux/ipv6.h> 14#include <linux/in.h> 15#include <linux/udp.h> 16#include <linux/tcp.h> 17#include <linux/pkt_cls.h> 18#include <sys/socket.h> 19#include <bpf/bpf_helpers.h> 20#include <bpf/bpf_endian.h> 21#include "test_iptunnel_common.h" 22 23struct { 24 __uint(type, BPF_MAP_TYPE_PERCPU_ARRAY); 25 __uint(max_entries, 256); 26 __type(key, __u32); 27 __type(value, __u64); 28} rxcnt SEC(".maps"); 29 30struct { 31 __uint(type, BPF_MAP_TYPE_HASH); 32 __uint(max_entries, MAX_IPTNL_ENTRIES); 33 __type(key, struct vip); 34 __type(value, struct iptnl_info); 35} vip2tnl SEC(".maps"); 36 37static __always_inline void count_tx(__u32 protocol) 38{ 39 __u64 *rxcnt_count; 40 41 rxcnt_count = bpf_map_lookup_elem(&rxcnt, &protocol); 42 if (rxcnt_count) 43 *rxcnt_count += 1; 44} 45 46static __always_inline int get_dport(void *trans_data, void *data_end, 47 __u8 protocol) 48{ 49 struct tcphdr *th; 50 struct udphdr *uh; 51 52 switch (protocol) { 53 case IPPROTO_TCP: 54 th = (struct tcphdr *)trans_data; 55 if (th + 1 > data_end) 56 return -1; 57 return th->dest; 58 case IPPROTO_UDP: 59 uh = (struct udphdr *)trans_data; 60 if (uh + 1 > data_end) 61 return -1; 62 return uh->dest; 63 default: 64 return 0; 65 } 66} 67 68static __always_inline void set_ethhdr(struct ethhdr *new_eth, 69 const struct ethhdr *old_eth, 70 const struct iptnl_info *tnl, 71 __be16 h_proto) 72{ 73 memcpy(new_eth->h_source, old_eth->h_dest, sizeof(new_eth->h_source)); 74 memcpy(new_eth->h_dest, tnl->dmac, sizeof(new_eth->h_dest)); 75 new_eth->h_proto = h_proto; 76} 77 78static __always_inline int handle_ipv4(struct xdp_md *xdp) 79{ 80 void *data_end = (void *)(long)xdp->data_end; 81 void *data = (void *)(long)xdp->data; 82 struct iptnl_info *tnl; 83 struct ethhdr *new_eth; 84 struct ethhdr *old_eth; 85 struct iphdr *iph = data + sizeof(struct ethhdr); 86 __u16 *next_iph; 87 __u16 payload_len; 88 struct vip vip = {}; 89 int dport; 90 __u32 csum = 0; 91 int i; 92 93 if (iph + 1 > data_end) 94 return XDP_DROP; 95 96 dport = get_dport(iph + 1, data_end, iph->protocol); 97 if (dport == -1) 98 return XDP_DROP; 99 100 vip.protocol = iph->protocol; 101 vip.family = AF_INET; 102 vip.daddr.v4 = iph->daddr; 103 vip.dport = dport; 104 payload_len = bpf_ntohs(iph->tot_len); 105 106 tnl = bpf_map_lookup_elem(&vip2tnl, &vip); 107 /* It only does v4-in-v4 */ 108 if (!tnl || tnl->family != AF_INET) 109 return XDP_PASS; 110 111 if (bpf_xdp_adjust_head(xdp, 0 - (int)sizeof(struct iphdr))) 112 return XDP_DROP; 113 114 data = (void *)(long)xdp->data; 115 data_end = (void *)(long)xdp->data_end; 116 117 new_eth = data; 118 iph = data + sizeof(*new_eth); 119 old_eth = data + sizeof(*iph); 120 121 if (new_eth + 1 > data_end || 122 old_eth + 1 > data_end || 123 iph + 1 > data_end) 124 return XDP_DROP; 125 126 set_ethhdr(new_eth, old_eth, tnl, bpf_htons(ETH_P_IP)); 127 128 iph->version = 4; 129 iph->ihl = sizeof(*iph) >> 2; 130 iph->frag_off = 0; 131 iph->protocol = IPPROTO_IPIP; 132 iph->check = 0; 133 iph->tos = 0; 134 iph->tot_len = bpf_htons(payload_len + sizeof(*iph)); 135 iph->daddr = tnl->daddr.v4; 136 iph->saddr = tnl->saddr.v4; 137 iph->ttl = 8; 138 139 next_iph = (__u16 *)iph; 140#pragma clang loop unroll(full) 141 for (i = 0; i < sizeof(*iph) >> 1; i++) 142 csum += *next_iph++; 143 144 iph->check = ~((csum & 0xffff) + (csum >> 16)); 145 146 count_tx(vip.protocol); 147 148 return XDP_TX; 149} 150 151static __always_inline int handle_ipv6(struct xdp_md *xdp) 152{ 153 void *data_end = (void *)(long)xdp->data_end; 154 void *data = (void *)(long)xdp->data; 155 struct iptnl_info *tnl; 156 struct ethhdr *new_eth; 157 struct ethhdr *old_eth; 158 struct ipv6hdr *ip6h = data + sizeof(struct ethhdr); 159 __u16 payload_len; 160 struct vip vip = {}; 161 int dport; 162 163 if (ip6h + 1 > data_end) 164 return XDP_DROP; 165 166 dport = get_dport(ip6h + 1, data_end, ip6h->nexthdr); 167 if (dport == -1) 168 return XDP_DROP; 169 170 vip.protocol = ip6h->nexthdr; 171 vip.family = AF_INET6; 172 memcpy(vip.daddr.v6, ip6h->daddr.s6_addr32, sizeof(vip.daddr)); 173 vip.dport = dport; 174 payload_len = ip6h->payload_len; 175 176 tnl = bpf_map_lookup_elem(&vip2tnl, &vip); 177 /* It only does v6-in-v6 */ 178 if (!tnl || tnl->family != AF_INET6) 179 return XDP_PASS; 180 181 if (bpf_xdp_adjust_head(xdp, 0 - (int)sizeof(struct ipv6hdr))) 182 return XDP_DROP; 183 184 data = (void *)(long)xdp->data; 185 data_end = (void *)(long)xdp->data_end; 186 187 new_eth = data; 188 ip6h = data + sizeof(*new_eth); 189 old_eth = data + sizeof(*ip6h); 190 191 if (new_eth + 1 > data_end || old_eth + 1 > data_end || 192 ip6h + 1 > data_end) 193 return XDP_DROP; 194 195 set_ethhdr(new_eth, old_eth, tnl, bpf_htons(ETH_P_IPV6)); 196 197 ip6h->version = 6; 198 ip6h->priority = 0; 199 memset(ip6h->flow_lbl, 0, sizeof(ip6h->flow_lbl)); 200 ip6h->payload_len = bpf_htons(bpf_ntohs(payload_len) + sizeof(*ip6h)); 201 ip6h->nexthdr = IPPROTO_IPV6; 202 ip6h->hop_limit = 8; 203 memcpy(ip6h->saddr.s6_addr32, tnl->saddr.v6, sizeof(tnl->saddr.v6)); 204 memcpy(ip6h->daddr.s6_addr32, tnl->daddr.v6, sizeof(tnl->daddr.v6)); 205 206 count_tx(vip.protocol); 207 208 return XDP_TX; 209} 210 211SEC("xdp") 212int _xdp_tx_iptunnel(struct xdp_md *xdp) 213{ 214 void *data_end = (void *)(long)xdp->data_end; 215 void *data = (void *)(long)xdp->data; 216 struct ethhdr *eth = data; 217 __u16 h_proto; 218 219 if (eth + 1 > data_end) 220 return XDP_DROP; 221 222 h_proto = eth->h_proto; 223 224 if (h_proto == bpf_htons(ETH_P_IP)) 225 return handle_ipv4(xdp); 226 else if (h_proto == bpf_htons(ETH_P_IPV6)) 227 228 return handle_ipv6(xdp); 229 else 230 return XDP_DROP; 231} 232 233char _license[] SEC("license") = "GPL"; 234