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12d8bb64 MKL |
1 | /* Copyright (c) 2016 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 | * This program shows how to use bpf_xdp_adjust_head() by | |
8 | * encapsulating the incoming packet in an IPv4/v6 header | |
9 | * and then XDP_TX it out. | |
10 | */ | |
cdb749ce | 11 | #define KBUILD_MODNAME "foo" |
12d8bb64 MKL |
12 | #include <uapi/linux/bpf.h> |
13 | #include <linux/in.h> | |
14 | #include <linux/if_ether.h> | |
15 | #include <linux/if_packet.h> | |
16 | #include <linux/if_vlan.h> | |
17 | #include <linux/ip.h> | |
18 | #include <linux/ipv6.h> | |
19 | #include "bpf_helpers.h" | |
20 | #include "xdp_tx_iptunnel_common.h" | |
21 | ||
22 | struct bpf_map_def SEC("maps") rxcnt = { | |
23 | .type = BPF_MAP_TYPE_PERCPU_ARRAY, | |
24 | .key_size = sizeof(__u32), | |
25 | .value_size = sizeof(__u64), | |
26 | .max_entries = 256, | |
27 | }; | |
28 | ||
29 | struct bpf_map_def SEC("maps") vip2tnl = { | |
30 | .type = BPF_MAP_TYPE_HASH, | |
31 | .key_size = sizeof(struct vip), | |
32 | .value_size = sizeof(struct iptnl_info), | |
33 | .max_entries = MAX_IPTNL_ENTRIES, | |
34 | }; | |
35 | ||
36 | static __always_inline void count_tx(u32 protocol) | |
37 | { | |
38 | u64 *rxcnt_count; | |
39 | ||
40 | rxcnt_count = bpf_map_lookup_elem(&rxcnt, &protocol); | |
41 | if (rxcnt_count) | |
42 | *rxcnt_count += 1; | |
43 | } | |
44 | ||
45 | static __always_inline int get_dport(void *trans_data, void *data_end, | |
46 | u8 protocol) | |
47 | { | |
48 | struct tcphdr *th; | |
49 | struct udphdr *uh; | |
50 | ||
51 | switch (protocol) { | |
52 | case IPPROTO_TCP: | |
53 | th = (struct tcphdr *)trans_data; | |
54 | if (th + 1 > data_end) | |
55 | return -1; | |
56 | return th->dest; | |
57 | case IPPROTO_UDP: | |
58 | uh = (struct udphdr *)trans_data; | |
59 | if (uh + 1 > data_end) | |
60 | return -1; | |
61 | return uh->dest; | |
62 | default: | |
63 | return 0; | |
64 | } | |
65 | } | |
66 | ||
67 | static __always_inline void set_ethhdr(struct ethhdr *new_eth, | |
68 | const struct ethhdr *old_eth, | |
69 | const struct iptnl_info *tnl, | |
70 | __be16 h_proto) | |
71 | { | |
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; | |
75 | } | |
76 | ||
77 | static __always_inline int handle_ipv4(struct xdp_md *xdp) | |
78 | { | |
79 | void *data_end = (void *)(long)xdp->data_end; | |
80 | void *data = (void *)(long)xdp->data; | |
81 | struct iptnl_info *tnl; | |
82 | struct ethhdr *new_eth; | |
83 | struct ethhdr *old_eth; | |
84 | struct iphdr *iph = data + sizeof(struct ethhdr); | |
85 | u16 *next_iph_u16; | |
86 | u16 payload_len; | |
87 | struct vip vip = {}; | |
88 | int dport; | |
89 | u32 csum = 0; | |
90 | int i; | |
91 | ||
92 | if (iph + 1 > data_end) | |
93 | return XDP_DROP; | |
94 | ||
95 | dport = get_dport(iph + 1, data_end, iph->protocol); | |
96 | if (dport == -1) | |
97 | return XDP_DROP; | |
98 | ||
99 | vip.protocol = iph->protocol; | |
100 | vip.family = AF_INET; | |
101 | vip.daddr.v4 = iph->daddr; | |
102 | vip.dport = dport; | |
103 | payload_len = ntohs(iph->tot_len); | |
104 | ||
105 | tnl = bpf_map_lookup_elem(&vip2tnl, &vip); | |
106 | /* It only does v4-in-v4 */ | |
107 | if (!tnl || tnl->family != AF_INET) | |
108 | return XDP_PASS; | |
109 | ||
110 | /* The vip key is found. Add an IP header and send it out */ | |
111 | ||
112 | if (bpf_xdp_adjust_head(xdp, 0 - (int)sizeof(struct iphdr))) | |
113 | return XDP_DROP; | |
114 | ||
115 | data = (void *)(long)xdp->data; | |
116 | data_end = (void *)(long)xdp->data_end; | |
117 | ||
118 | new_eth = data; | |
119 | iph = data + sizeof(*new_eth); | |
120 | old_eth = data + sizeof(*iph); | |
121 | ||
122 | if (new_eth + 1 > data_end || | |
123 | old_eth + 1 > data_end || | |
124 | iph + 1 > data_end) | |
125 | return XDP_DROP; | |
126 | ||
127 | set_ethhdr(new_eth, old_eth, tnl, htons(ETH_P_IP)); | |
128 | ||
129 | iph->version = 4; | |
130 | iph->ihl = sizeof(*iph) >> 2; | |
131 | iph->frag_off = 0; | |
132 | iph->protocol = IPPROTO_IPIP; | |
133 | iph->check = 0; | |
134 | iph->tos = 0; | |
135 | iph->tot_len = htons(payload_len + sizeof(*iph)); | |
136 | iph->daddr = tnl->daddr.v4; | |
137 | iph->saddr = tnl->saddr.v4; | |
138 | iph->ttl = 8; | |
139 | ||
140 | next_iph_u16 = (u16 *)iph; | |
141 | #pragma clang loop unroll(full) | |
142 | for (i = 0; i < sizeof(*iph) >> 1; i++) | |
143 | csum += *next_iph_u16++; | |
144 | ||
145 | iph->check = ~((csum & 0xffff) + (csum >> 16)); | |
146 | ||
147 | count_tx(vip.protocol); | |
148 | ||
149 | return XDP_TX; | |
150 | } | |
151 | ||
152 | static __always_inline int handle_ipv6(struct xdp_md *xdp) | |
153 | { | |
154 | void *data_end = (void *)(long)xdp->data_end; | |
155 | void *data = (void *)(long)xdp->data; | |
156 | struct iptnl_info *tnl; | |
157 | struct ethhdr *new_eth; | |
158 | struct ethhdr *old_eth; | |
159 | struct ipv6hdr *ip6h = data + sizeof(struct ethhdr); | |
160 | __u16 payload_len; | |
161 | struct vip vip = {}; | |
162 | int dport; | |
163 | ||
164 | if (ip6h + 1 > data_end) | |
165 | return XDP_DROP; | |
166 | ||
167 | dport = get_dport(ip6h + 1, data_end, ip6h->nexthdr); | |
168 | if (dport == -1) | |
169 | return XDP_DROP; | |
170 | ||
171 | vip.protocol = ip6h->nexthdr; | |
172 | vip.family = AF_INET6; | |
173 | memcpy(vip.daddr.v6, ip6h->daddr.s6_addr32, sizeof(vip.daddr)); | |
174 | vip.dport = dport; | |
175 | payload_len = ip6h->payload_len; | |
176 | ||
177 | tnl = bpf_map_lookup_elem(&vip2tnl, &vip); | |
178 | /* It only does v6-in-v6 */ | |
179 | if (!tnl || tnl->family != AF_INET6) | |
180 | return XDP_PASS; | |
181 | ||
182 | /* The vip key is found. Add an IP header and send it out */ | |
183 | ||
184 | if (bpf_xdp_adjust_head(xdp, 0 - (int)sizeof(struct ipv6hdr))) | |
185 | return XDP_DROP; | |
186 | ||
187 | data = (void *)(long)xdp->data; | |
188 | data_end = (void *)(long)xdp->data_end; | |
189 | ||
190 | new_eth = data; | |
191 | ip6h = data + sizeof(*new_eth); | |
192 | old_eth = data + sizeof(*ip6h); | |
193 | ||
194 | if (new_eth + 1 > data_end || | |
195 | old_eth + 1 > data_end || | |
196 | ip6h + 1 > data_end) | |
197 | return XDP_DROP; | |
198 | ||
199 | set_ethhdr(new_eth, old_eth, tnl, htons(ETH_P_IPV6)); | |
200 | ||
201 | ip6h->version = 6; | |
202 | ip6h->priority = 0; | |
203 | memset(ip6h->flow_lbl, 0, sizeof(ip6h->flow_lbl)); | |
204 | ip6h->payload_len = htons(ntohs(payload_len) + sizeof(*ip6h)); | |
205 | ip6h->nexthdr = IPPROTO_IPV6; | |
206 | ip6h->hop_limit = 8; | |
207 | memcpy(ip6h->saddr.s6_addr32, tnl->saddr.v6, sizeof(tnl->saddr.v6)); | |
208 | memcpy(ip6h->daddr.s6_addr32, tnl->daddr.v6, sizeof(tnl->daddr.v6)); | |
209 | ||
210 | count_tx(vip.protocol); | |
211 | ||
212 | return XDP_TX; | |
213 | } | |
214 | ||
215 | SEC("xdp_tx_iptunnel") | |
216 | int _xdp_tx_iptunnel(struct xdp_md *xdp) | |
217 | { | |
218 | void *data_end = (void *)(long)xdp->data_end; | |
219 | void *data = (void *)(long)xdp->data; | |
220 | struct ethhdr *eth = data; | |
221 | __u16 h_proto; | |
222 | ||
223 | if (eth + 1 > data_end) | |
224 | return XDP_DROP; | |
225 | ||
226 | h_proto = eth->h_proto; | |
227 | ||
228 | if (h_proto == htons(ETH_P_IP)) | |
229 | return handle_ipv4(xdp); | |
230 | else if (h_proto == htons(ETH_P_IPV6)) | |
231 | ||
232 | return handle_ipv6(xdp); | |
233 | else | |
234 | return XDP_PASS; | |
235 | } | |
236 | ||
237 | char _license[] SEC("license") = "GPL"; |