1 // SPDX-License-Identifier: GPL-2.0
2 /* Copyright (c) 2022 Meta */
7 #include <linux/if_ether.h>
8 #include <linux/if_packet.h>
10 #include <linux/ipv6.h>
12 #include <linux/udp.h>
13 #include <linux/tcp.h>
14 #include <linux/pkt_cls.h>
15 #include <sys/socket.h>
16 #include <bpf/bpf_helpers.h>
17 #include <bpf/bpf_endian.h>
18 #include "test_iptunnel_common.h"
19 #include "bpf_kfuncs.h"
21 const size_t tcphdr_sz = sizeof(struct tcphdr);
22 const size_t udphdr_sz = sizeof(struct udphdr);
23 const size_t ethhdr_sz = sizeof(struct ethhdr);
24 const size_t iphdr_sz = sizeof(struct iphdr);
25 const size_t ipv6hdr_sz = sizeof(struct ipv6hdr);
28 __uint(type, BPF_MAP_TYPE_PERCPU_ARRAY);
29 __uint(max_entries, 256);
35 __uint(type, BPF_MAP_TYPE_HASH);
36 __uint(max_entries, MAX_IPTNL_ENTRIES);
37 __type(key, struct vip);
38 __type(value, struct iptnl_info);
39 } vip2tnl SEC(".maps");
41 static __always_inline void count_tx(__u32 protocol)
45 rxcnt_count = bpf_map_lookup_elem(&rxcnt, &protocol);
50 static __always_inline int get_dport(void *trans_data, __u8 protocol)
57 th = (struct tcphdr *)trans_data;
60 uh = (struct udphdr *)trans_data;
67 static __always_inline void set_ethhdr(struct ethhdr *new_eth,
68 const struct ethhdr *old_eth,
69 const struct iptnl_info *tnl,
72 memcpy(new_eth->h_source, old_eth->h_dest, sizeof(new_eth->h_source));
73 memcpy(new_eth->h_dest, tnl->dmac, sizeof(new_eth->h_dest));
74 new_eth->h_proto = h_proto;
77 static __always_inline int handle_ipv4(struct xdp_md *xdp, struct bpf_dynptr *xdp_ptr)
79 __u8 eth_buffer[ethhdr_sz + iphdr_sz + ethhdr_sz];
80 __u8 iph_buffer_tcp[iphdr_sz + tcphdr_sz];
81 __u8 iph_buffer_udp[iphdr_sz + udphdr_sz];
82 struct bpf_dynptr new_xdp_ptr;
83 struct iptnl_info *tnl;
84 struct ethhdr *new_eth;
85 struct ethhdr *old_eth;
94 __builtin_memset(eth_buffer, 0, sizeof(eth_buffer));
95 __builtin_memset(iph_buffer_tcp, 0, sizeof(iph_buffer_tcp));
96 __builtin_memset(iph_buffer_udp, 0, sizeof(iph_buffer_udp));
98 if (ethhdr_sz + iphdr_sz + tcphdr_sz > xdp->data_end - xdp->data)
99 iph = bpf_dynptr_slice(xdp_ptr, ethhdr_sz, iph_buffer_udp, sizeof(iph_buffer_udp));
101 iph = bpf_dynptr_slice(xdp_ptr, ethhdr_sz, iph_buffer_tcp, sizeof(iph_buffer_tcp));
106 dport = get_dport(iph + 1, iph->protocol);
110 vip.protocol = iph->protocol;
111 vip.family = AF_INET;
112 vip.daddr.v4 = iph->daddr;
114 payload_len = bpf_ntohs(iph->tot_len);
116 tnl = bpf_map_lookup_elem(&vip2tnl, &vip);
117 /* It only does v4-in-v4 */
118 if (!tnl || tnl->family != AF_INET)
121 if (bpf_xdp_adjust_head(xdp, 0 - (int)iphdr_sz))
124 bpf_dynptr_from_xdp(xdp, 0, &new_xdp_ptr);
125 new_eth = bpf_dynptr_slice_rdwr(&new_xdp_ptr, 0, eth_buffer, sizeof(eth_buffer));
129 iph = (struct iphdr *)(new_eth + 1);
130 old_eth = (struct ethhdr *)(iph + 1);
132 set_ethhdr(new_eth, old_eth, tnl, bpf_htons(ETH_P_IP));
134 if (new_eth == eth_buffer)
135 bpf_dynptr_write(&new_xdp_ptr, 0, eth_buffer, sizeof(eth_buffer), 0);
138 iph->ihl = iphdr_sz >> 2;
140 iph->protocol = IPPROTO_IPIP;
143 iph->tot_len = bpf_htons(payload_len + iphdr_sz);
144 iph->daddr = tnl->daddr.v4;
145 iph->saddr = tnl->saddr.v4;
148 next_iph = (__u16 *)iph;
149 for (i = 0; i < iphdr_sz >> 1; i++)
152 iph->check = ~((csum & 0xffff) + (csum >> 16));
154 count_tx(vip.protocol);
159 static __always_inline int handle_ipv6(struct xdp_md *xdp, struct bpf_dynptr *xdp_ptr)
161 __u8 eth_buffer[ethhdr_sz + ipv6hdr_sz + ethhdr_sz];
162 __u8 ip6h_buffer_tcp[ipv6hdr_sz + tcphdr_sz];
163 __u8 ip6h_buffer_udp[ipv6hdr_sz + udphdr_sz];
164 struct bpf_dynptr new_xdp_ptr;
165 struct iptnl_info *tnl;
166 struct ethhdr *new_eth;
167 struct ethhdr *old_eth;
168 struct ipv6hdr *ip6h;
173 __builtin_memset(eth_buffer, 0, sizeof(eth_buffer));
174 __builtin_memset(ip6h_buffer_tcp, 0, sizeof(ip6h_buffer_tcp));
175 __builtin_memset(ip6h_buffer_udp, 0, sizeof(ip6h_buffer_udp));
177 if (ethhdr_sz + iphdr_sz + tcphdr_sz > xdp->data_end - xdp->data)
178 ip6h = bpf_dynptr_slice(xdp_ptr, ethhdr_sz, ip6h_buffer_udp, sizeof(ip6h_buffer_udp));
180 ip6h = bpf_dynptr_slice(xdp_ptr, ethhdr_sz, ip6h_buffer_tcp, sizeof(ip6h_buffer_tcp));
185 dport = get_dport(ip6h + 1, ip6h->nexthdr);
189 vip.protocol = ip6h->nexthdr;
190 vip.family = AF_INET6;
191 memcpy(vip.daddr.v6, ip6h->daddr.s6_addr32, sizeof(vip.daddr));
193 payload_len = ip6h->payload_len;
195 tnl = bpf_map_lookup_elem(&vip2tnl, &vip);
196 /* It only does v6-in-v6 */
197 if (!tnl || tnl->family != AF_INET6)
200 if (bpf_xdp_adjust_head(xdp, 0 - (int)ipv6hdr_sz))
203 bpf_dynptr_from_xdp(xdp, 0, &new_xdp_ptr);
204 new_eth = bpf_dynptr_slice_rdwr(&new_xdp_ptr, 0, eth_buffer, sizeof(eth_buffer));
208 ip6h = (struct ipv6hdr *)(new_eth + 1);
209 old_eth = (struct ethhdr *)(ip6h + 1);
211 set_ethhdr(new_eth, old_eth, tnl, bpf_htons(ETH_P_IPV6));
213 if (new_eth == eth_buffer)
214 bpf_dynptr_write(&new_xdp_ptr, 0, eth_buffer, sizeof(eth_buffer), 0);
218 memset(ip6h->flow_lbl, 0, sizeof(ip6h->flow_lbl));
219 ip6h->payload_len = bpf_htons(bpf_ntohs(payload_len) + ipv6hdr_sz);
220 ip6h->nexthdr = IPPROTO_IPV6;
222 memcpy(ip6h->saddr.s6_addr32, tnl->saddr.v6, sizeof(tnl->saddr.v6));
223 memcpy(ip6h->daddr.s6_addr32, tnl->daddr.v6, sizeof(tnl->daddr.v6));
225 count_tx(vip.protocol);
231 int _xdp_tx_iptunnel(struct xdp_md *xdp)
233 __u8 buffer[ethhdr_sz];
234 struct bpf_dynptr ptr;
238 __builtin_memset(buffer, 0, sizeof(buffer));
240 bpf_dynptr_from_xdp(xdp, 0, &ptr);
241 eth = bpf_dynptr_slice(&ptr, 0, buffer, sizeof(buffer));
245 h_proto = eth->h_proto;
247 if (h_proto == bpf_htons(ETH_P_IP))
248 return handle_ipv4(xdp, &ptr);
249 else if (h_proto == bpf_htons(ETH_P_IPV6))
251 return handle_ipv6(xdp, &ptr);
256 char _license[] SEC("license") = "GPL";