1 // SPDX-License-Identifier: GPL-2.0 2 // Copyright (c) 2019 Facebook 3 #include <stddef.h> 4 #include <string.h> 5 #include <linux/bpf.h> 6 #include <linux/if_ether.h> 7 #include <linux/if_packet.h> 8 #include <linux/ip.h> 9 #include <linux/ipv6.h> 10 #include <linux/in.h> 11 #include <linux/udp.h> 12 #include <linux/tcp.h> 13 #include <linux/pkt_cls.h> 14 #include <sys/socket.h> 15 #include <bpf/bpf_helpers.h> 16 #include <bpf/bpf_endian.h> 17 #include "test_iptunnel_common.h" 18 #include "bpf_compiler.h" 19 20 struct { 21 __uint(type, BPF_MAP_TYPE_PERCPU_ARRAY); 22 __uint(max_entries, 256); 23 __type(key, __u32); 24 __type(value, __u64); 25 } rxcnt SEC(".maps"); 26 27 struct { 28 __uint(type, BPF_MAP_TYPE_HASH); 29 __uint(max_entries, MAX_IPTNL_ENTRIES); 30 __type(key, struct vip); 31 __type(value, struct iptnl_info); 32 } vip2tnl SEC(".maps"); 33 34 static __always_inline void count_tx(__u32 protocol) 35 { 36 __u64 *rxcnt_count; 37 38 rxcnt_count = bpf_map_lookup_elem(&rxcnt, &protocol); 39 if (rxcnt_count) 40 *rxcnt_count += 1; 41 } 42 43 static __always_inline int get_dport(void *trans_data, void *data_end, 44 __u8 protocol) 45 { 46 struct tcphdr *th; 47 struct udphdr *uh; 48 49 switch (protocol) { 50 case IPPROTO_TCP: 51 th = (struct tcphdr *)trans_data; 52 if (th + 1 > data_end) 53 return -1; 54 return th->dest; 55 case IPPROTO_UDP: 56 uh = (struct udphdr *)trans_data; 57 if (uh + 1 > data_end) 58 return -1; 59 return uh->dest; 60 default: 61 return 0; 62 } 63 } 64 65 static __always_inline void set_ethhdr(struct ethhdr *new_eth, 66 const struct ethhdr *old_eth, 67 const struct iptnl_info *tnl, 68 __be16 h_proto) 69 { 70 memcpy(new_eth->h_source, old_eth->h_dest, sizeof(new_eth->h_source)); 71 memcpy(new_eth->h_dest, tnl->dmac, sizeof(new_eth->h_dest)); 72 new_eth->h_proto = h_proto; 73 } 74 75 static __always_inline int handle_ipv4(struct xdp_md *xdp) 76 { 77 void *data_end = (void *)(long)xdp->data_end; 78 void *data = (void *)(long)xdp->data; 79 struct iptnl_info *tnl; 80 struct ethhdr *new_eth; 81 struct ethhdr *old_eth; 82 struct iphdr *iph = data + sizeof(struct ethhdr); 83 __u16 *next_iph; 84 __u16 payload_len; 85 struct vip vip = {}; 86 int dport; 87 __u32 csum = 0; 88 int i; 89 90 if (iph + 1 > data_end) 91 return XDP_DROP; 92 93 dport = get_dport(iph + 1, data_end, iph->protocol); 94 if (dport == -1) 95 return XDP_DROP; 96 97 vip.protocol = iph->protocol; 98 vip.family = AF_INET; 99 vip.daddr.v4 = iph->daddr; 100 vip.dport = dport; 101 payload_len = bpf_ntohs(iph->tot_len); 102 103 tnl = bpf_map_lookup_elem(&vip2tnl, &vip); 104 /* It only does v4-in-v4 */ 105 if (!tnl || tnl->family != AF_INET) 106 return XDP_PASS; 107 108 if (bpf_xdp_adjust_head(xdp, 0 - (int)sizeof(struct iphdr))) 109 return XDP_DROP; 110 111 data = (void *)(long)xdp->data; 112 data_end = (void *)(long)xdp->data_end; 113 114 new_eth = data; 115 iph = data + sizeof(*new_eth); 116 old_eth = data + sizeof(*iph); 117 118 if (new_eth + 1 > data_end || 119 old_eth + 1 > data_end || 120 iph + 1 > data_end) 121 return XDP_DROP; 122 123 set_ethhdr(new_eth, old_eth, tnl, bpf_htons(ETH_P_IP)); 124 125 iph->version = 4; 126 iph->ihl = sizeof(*iph) >> 2; 127 iph->frag_off = 0; 128 iph->protocol = IPPROTO_IPIP; 129 iph->check = 0; 130 iph->tos = 0; 131 iph->tot_len = bpf_htons(payload_len + sizeof(*iph)); 132 iph->daddr = tnl->daddr.v4; 133 iph->saddr = tnl->saddr.v4; 134 iph->ttl = 8; 135 136 next_iph = (__u16 *)iph; 137 __pragma_loop_no_unroll 138 for (i = 0; i < sizeof(*iph) >> 1; i++) 139 csum += *next_iph++; 140 141 iph->check = ~((csum & 0xffff) + (csum >> 16)); 142 143 count_tx(vip.protocol); 144 145 return XDP_TX; 146 } 147 148 static __always_inline int handle_ipv6(struct xdp_md *xdp) 149 { 150 void *data_end = (void *)(long)xdp->data_end; 151 void *data = (void *)(long)xdp->data; 152 struct iptnl_info *tnl; 153 struct ethhdr *new_eth; 154 struct ethhdr *old_eth; 155 struct ipv6hdr *ip6h = data + sizeof(struct ethhdr); 156 __u16 payload_len; 157 struct vip vip = {}; 158 int dport; 159 160 if (ip6h + 1 > data_end) 161 return XDP_DROP; 162 163 dport = get_dport(ip6h + 1, data_end, ip6h->nexthdr); 164 if (dport == -1) 165 return XDP_DROP; 166 167 vip.protocol = ip6h->nexthdr; 168 vip.family = AF_INET6; 169 memcpy(vip.daddr.v6, ip6h->daddr.s6_addr32, sizeof(vip.daddr)); 170 vip.dport = dport; 171 payload_len = ip6h->payload_len; 172 173 tnl = bpf_map_lookup_elem(&vip2tnl, &vip); 174 /* It only does v6-in-v6 */ 175 if (!tnl || tnl->family != AF_INET6) 176 return XDP_PASS; 177 178 if (bpf_xdp_adjust_head(xdp, 0 - (int)sizeof(struct ipv6hdr))) 179 return XDP_DROP; 180 181 data = (void *)(long)xdp->data; 182 data_end = (void *)(long)xdp->data_end; 183 184 new_eth = data; 185 ip6h = data + sizeof(*new_eth); 186 old_eth = data + sizeof(*ip6h); 187 188 if (new_eth + 1 > data_end || old_eth + 1 > data_end || 189 ip6h + 1 > data_end) 190 return XDP_DROP; 191 192 set_ethhdr(new_eth, old_eth, tnl, bpf_htons(ETH_P_IPV6)); 193 194 ip6h->version = 6; 195 ip6h->priority = 0; 196 memset(ip6h->flow_lbl, 0, sizeof(ip6h->flow_lbl)); 197 ip6h->payload_len = bpf_htons(bpf_ntohs(payload_len) + sizeof(*ip6h)); 198 ip6h->nexthdr = IPPROTO_IPV6; 199 ip6h->hop_limit = 8; 200 memcpy(ip6h->saddr.s6_addr32, tnl->saddr.v6, sizeof(tnl->saddr.v6)); 201 memcpy(ip6h->daddr.s6_addr32, tnl->daddr.v6, sizeof(tnl->daddr.v6)); 202 203 count_tx(vip.protocol); 204 205 return XDP_TX; 206 } 207 208 SEC("xdp") 209 int _xdp_tx_iptunnel(struct xdp_md *xdp) 210 { 211 void *data_end = (void *)(long)xdp->data_end; 212 void *data = (void *)(long)xdp->data; 213 struct ethhdr *eth = data; 214 __u16 h_proto; 215 216 if (eth + 1 > data_end) 217 return XDP_DROP; 218 219 h_proto = eth->h_proto; 220 221 if (h_proto == bpf_htons(ETH_P_IP)) 222 return handle_ipv4(xdp); 223 else if (h_proto == bpf_htons(ETH_P_IPV6)) 224 225 return handle_ipv6(xdp); 226 else 227 return XDP_DROP; 228 } 229 230 char _license[] SEC("license") = "GPL"; 231