1
2
3
4
5
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_helpers.h"
20#include "bpf_endian.h"
21#include "test_iptunnel_common.h"
22
23int _version SEC("version") = 1;
24
25struct bpf_map_def SEC("maps") rxcnt = {
26 .type = BPF_MAP_TYPE_PERCPU_ARRAY,
27 .key_size = sizeof(__u32),
28 .value_size = sizeof(__u64),
29 .max_entries = 256,
30};
31
32struct bpf_map_def SEC("maps") vip2tnl = {
33 .type = BPF_MAP_TYPE_HASH,
34 .key_size = sizeof(struct vip),
35 .value_size = sizeof(struct iptnl_info),
36 .max_entries = MAX_IPTNL_ENTRIES,
37};
38
39static __always_inline void count_tx(__u32 protocol)
40{
41 __u64 *rxcnt_count;
42
43 rxcnt_count = bpf_map_lookup_elem(&rxcnt, &protocol);
44 if (rxcnt_count)
45 *rxcnt_count += 1;
46}
47
48static __always_inline int get_dport(void *trans_data, void *data_end,
49 __u8 protocol)
50{
51 struct tcphdr *th;
52 struct udphdr *uh;
53
54 switch (protocol) {
55 case IPPROTO_TCP:
56 th = (struct tcphdr *)trans_data;
57 if (th + 1 > data_end)
58 return -1;
59 return th->dest;
60 case IPPROTO_UDP:
61 uh = (struct udphdr *)trans_data;
62 if (uh + 1 > data_end)
63 return -1;
64 return uh->dest;
65 default:
66 return 0;
67 }
68}
69
70static __always_inline void set_ethhdr(struct ethhdr *new_eth,
71 const struct ethhdr *old_eth,
72 const struct iptnl_info *tnl,
73 __be16 h_proto)
74{
75 memcpy(new_eth->h_source, old_eth->h_dest, sizeof(new_eth->h_source));
76 memcpy(new_eth->h_dest, tnl->dmac, sizeof(new_eth->h_dest));
77 new_eth->h_proto = h_proto;
78}
79
80static __always_inline int handle_ipv4(struct xdp_md *xdp)
81{
82 void *data_end = (void *)(long)xdp->data_end;
83 void *data = (void *)(long)xdp->data;
84 struct iptnl_info *tnl;
85 struct ethhdr *new_eth;
86 struct ethhdr *old_eth;
87 struct iphdr *iph = data + sizeof(struct ethhdr);
88 __u16 *next_iph;
89 __u16 payload_len;
90 struct vip vip = {};
91 int dport;
92 __u32 csum = 0;
93 int i;
94
95 if (iph + 1 > data_end)
96 return XDP_DROP;
97
98 dport = get_dport(iph + 1, data_end, iph->protocol);
99 if (dport == -1)
100 return XDP_DROP;
101
102 vip.protocol = iph->protocol;
103 vip.family = AF_INET;
104 vip.daddr.v4 = iph->daddr;
105 vip.dport = dport;
106 payload_len = bpf_ntohs(iph->tot_len);
107
108 tnl = bpf_map_lookup_elem(&vip2tnl, &vip);
109
110 if (!tnl || tnl->family != AF_INET)
111 return XDP_PASS;
112
113 if (bpf_xdp_adjust_head(xdp, 0 - (int)sizeof(struct iphdr)))
114 return XDP_DROP;
115
116 data = (void *)(long)xdp->data;
117 data_end = (void *)(long)xdp->data_end;
118
119 new_eth = data;
120 iph = data + sizeof(*new_eth);
121 old_eth = data + sizeof(*iph);
122
123 if (new_eth + 1 > data_end ||
124 old_eth + 1 > data_end ||
125 iph + 1 > data_end)
126 return XDP_DROP;
127
128 set_ethhdr(new_eth, old_eth, tnl, bpf_htons(ETH_P_IP));
129
130 iph->version = 4;
131 iph->ihl = sizeof(*iph) >> 2;
132 iph->frag_off = 0;
133 iph->protocol = IPPROTO_IPIP;
134 iph->check = 0;
135 iph->tos = 0;
136 iph->tot_len = bpf_htons(payload_len + sizeof(*iph));
137 iph->daddr = tnl->daddr.v4;
138 iph->saddr = tnl->saddr.v4;
139 iph->ttl = 8;
140
141 next_iph = (__u16 *)iph;
142#pragma clang loop unroll(full)
143 for (i = 0; i < sizeof(*iph) >> 1; i++)
144 csum += *next_iph++;
145
146 iph->check = ~((csum & 0xffff) + (csum >> 16));
147
148 count_tx(vip.protocol);
149
150 return XDP_TX;
151}
152
153static __always_inline int handle_ipv6(struct xdp_md *xdp)
154{
155 void *data_end = (void *)(long)xdp->data_end;
156 void *data = (void *)(long)xdp->data;
157 struct iptnl_info *tnl;
158 struct ethhdr *new_eth;
159 struct ethhdr *old_eth;
160 struct ipv6hdr *ip6h = data + sizeof(struct ethhdr);
161 __u16 payload_len;
162 struct vip vip = {};
163 int dport;
164
165 if (ip6h + 1 > data_end)
166 return XDP_DROP;
167
168 dport = get_dport(ip6h + 1, data_end, ip6h->nexthdr);
169 if (dport == -1)
170 return XDP_DROP;
171
172 vip.protocol = ip6h->nexthdr;
173 vip.family = AF_INET6;
174 memcpy(vip.daddr.v6, ip6h->daddr.s6_addr32, sizeof(vip.daddr));
175 vip.dport = dport;
176 payload_len = ip6h->payload_len;
177
178 tnl = bpf_map_lookup_elem(&vip2tnl, &vip);
179
180 if (!tnl || tnl->family != AF_INET6)
181 return XDP_PASS;
182
183 if (bpf_xdp_adjust_head(xdp, 0 - (int)sizeof(struct ipv6hdr)))
184 return XDP_DROP;
185
186 data = (void *)(long)xdp->data;
187 data_end = (void *)(long)xdp->data_end;
188
189 new_eth = data;
190 ip6h = data + sizeof(*new_eth);
191 old_eth = data + sizeof(*ip6h);
192
193 if (new_eth + 1 > data_end || old_eth + 1 > data_end ||
194 ip6h + 1 > data_end)
195 return XDP_DROP;
196
197 set_ethhdr(new_eth, old_eth, tnl, bpf_htons(ETH_P_IPV6));
198
199 ip6h->version = 6;
200 ip6h->priority = 0;
201 memset(ip6h->flow_lbl, 0, sizeof(ip6h->flow_lbl));
202 ip6h->payload_len = bpf_htons(bpf_ntohs(payload_len) + sizeof(*ip6h));
203 ip6h->nexthdr = IPPROTO_IPV6;
204 ip6h->hop_limit = 8;
205 memcpy(ip6h->saddr.s6_addr32, tnl->saddr.v6, sizeof(tnl->saddr.v6));
206 memcpy(ip6h->daddr.s6_addr32, tnl->daddr.v6, sizeof(tnl->daddr.v6));
207
208 count_tx(vip.protocol);
209
210 return XDP_TX;
211}
212
213SEC("xdp_tx_iptunnel")
214int _xdp_tx_iptunnel(struct xdp_md *xdp)
215{
216 void *data_end = (void *)(long)xdp->data_end;
217 void *data = (void *)(long)xdp->data;
218 struct ethhdr *eth = data;
219 __u16 h_proto;
220
221 if (eth + 1 > data_end)
222 return XDP_DROP;
223
224 h_proto = eth->h_proto;
225
226 if (h_proto == bpf_htons(ETH_P_IP))
227 return handle_ipv4(xdp);
228 else if (h_proto == bpf_htons(ETH_P_IPV6))
229
230 return handle_ipv6(xdp);
231 else
232 return XDP_DROP;
233}
234
235char _license[] SEC("license") = "GPL";
236
