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1// SPDX-License-Identifier: GPL-2.0
2
3/* In-place tunneling */
4
5#include <stdbool.h>
6#include <string.h>
7
8#include <linux/stddef.h>
9#include <linux/bpf.h>
10#include <linux/if_ether.h>
11#include <linux/in.h>
12#include <linux/ip.h>
13#include <linux/ipv6.h>
14#include <linux/mpls.h>
15#include <linux/tcp.h>
16#include <linux/udp.h>
17#include <linux/pkt_cls.h>
18#include <linux/types.h>
19
20#include <bpf/bpf_endian.h>
21#include <bpf/bpf_helpers.h>
22
23static const int cfg_port = 8000;
24
25static const int cfg_udp_src = 20000;
26
27#define UDP_PORT 5555
28#define MPLS_OVER_UDP_PORT 6635
29#define ETH_OVER_UDP_PORT 7777
30
31/* MPLS label 1000 with S bit (last label) set and ttl of 255. */
32static const __u32 mpls_label = __bpf_constant_htonl(1000 << 12 |
33 MPLS_LS_S_MASK | 0xff);
34
35struct gre_hdr {
36 __be16 flags;
37 __be16 protocol;
38} __attribute__((packed));
39
40union l4hdr {
41 struct udphdr udp;
42 struct gre_hdr gre;
43};
44
45struct v4hdr {
46 struct iphdr ip;
47 union l4hdr l4hdr;
48 __u8 pad[16]; /* enough space for L2 header */
49} __attribute__((packed));
50
51struct v6hdr {
52 struct ipv6hdr ip;
53 union l4hdr l4hdr;
54 __u8 pad[16]; /* enough space for L2 header */
55} __attribute__((packed));
56
57static __always_inline void set_ipv4_csum(struct iphdr *iph)
58{
59 __u16 *iph16 = (__u16 *)iph;
60 __u32 csum;
61 int i;
62
63 iph->check = 0;
64
65#pragma clang loop unroll(full)
66 for (i = 0, csum = 0; i < sizeof(*iph) >> 1; i++)
67 csum += *iph16++;
68
69 iph->check = ~((csum & 0xffff) + (csum >> 16));
70}
71
72static __always_inline int encap_ipv4(struct __sk_buff *skb, __u8 encap_proto,
73 __u16 l2_proto)
74{
75 __u16 udp_dst = UDP_PORT;
76 struct iphdr iph_inner;
77 struct v4hdr h_outer;
78 struct tcphdr tcph;
79 int olen, l2_len;
80 int tcp_off;
81 __u64 flags;
82
83 /* Most tests encapsulate a packet into a tunnel with the same
84 * network protocol, and derive the outer header fields from
85 * the inner header.
86 *
87 * The 6in4 case tests different inner and outer protocols. As
88 * the inner is ipv6, but the outer expects an ipv4 header as
89 * input, manually build a struct iphdr based on the ipv6hdr.
90 */
91 if (encap_proto == IPPROTO_IPV6) {
92 const __u32 saddr = (192 << 24) | (168 << 16) | (1 << 8) | 1;
93 const __u32 daddr = (192 << 24) | (168 << 16) | (1 << 8) | 2;
94 struct ipv6hdr iph6_inner;
95
96 /* Read the IPv6 header */
97 if (bpf_skb_load_bytes(skb, ETH_HLEN, &iph6_inner,
98 sizeof(iph6_inner)) < 0)
99 return TC_ACT_OK;
100
101 /* Derive the IPv4 header fields from the IPv6 header */
102 memset(&iph_inner, 0, sizeof(iph_inner));
103 iph_inner.version = 4;
104 iph_inner.ihl = 5;
105 iph_inner.tot_len = bpf_htons(sizeof(iph6_inner) +
106 bpf_ntohs(iph6_inner.payload_len));
107 iph_inner.ttl = iph6_inner.hop_limit - 1;
108 iph_inner.protocol = iph6_inner.nexthdr;
109 iph_inner.saddr = __bpf_constant_htonl(saddr);
110 iph_inner.daddr = __bpf_constant_htonl(daddr);
111
112 tcp_off = sizeof(iph6_inner);
113 } else {
114 if (bpf_skb_load_bytes(skb, ETH_HLEN, &iph_inner,
115 sizeof(iph_inner)) < 0)
116 return TC_ACT_OK;
117
118 tcp_off = sizeof(iph_inner);
119 }
120
121 /* filter only packets we want */
122 if (iph_inner.ihl != 5 || iph_inner.protocol != IPPROTO_TCP)
123 return TC_ACT_OK;
124
125 if (bpf_skb_load_bytes(skb, ETH_HLEN + tcp_off,
126 &tcph, sizeof(tcph)) < 0)
127 return TC_ACT_OK;
128
129 if (tcph.dest != __bpf_constant_htons(cfg_port))
130 return TC_ACT_OK;
131
132 olen = sizeof(h_outer.ip);
133 l2_len = 0;
134
135 flags = BPF_F_ADJ_ROOM_FIXED_GSO | BPF_F_ADJ_ROOM_ENCAP_L3_IPV4;
136
137 switch (l2_proto) {
138 case ETH_P_MPLS_UC:
139 l2_len = sizeof(mpls_label);
140 udp_dst = MPLS_OVER_UDP_PORT;
141 break;
142 case ETH_P_TEB:
143 l2_len = ETH_HLEN;
144 udp_dst = ETH_OVER_UDP_PORT;
145 break;
146 }
147 flags |= BPF_F_ADJ_ROOM_ENCAP_L2(l2_len);
148
149 switch (encap_proto) {
150 case IPPROTO_GRE:
151 flags |= BPF_F_ADJ_ROOM_ENCAP_L4_GRE;
152 olen += sizeof(h_outer.l4hdr.gre);
153 h_outer.l4hdr.gre.protocol = bpf_htons(l2_proto);
154 h_outer.l4hdr.gre.flags = 0;
155 break;
156 case IPPROTO_UDP:
157 flags |= BPF_F_ADJ_ROOM_ENCAP_L4_UDP;
158 olen += sizeof(h_outer.l4hdr.udp);
159 h_outer.l4hdr.udp.source = __bpf_constant_htons(cfg_udp_src);
160 h_outer.l4hdr.udp.dest = bpf_htons(udp_dst);
161 h_outer.l4hdr.udp.check = 0;
162 h_outer.l4hdr.udp.len = bpf_htons(bpf_ntohs(iph_inner.tot_len) +
163 sizeof(h_outer.l4hdr.udp) +
164 l2_len);
165 break;
166 case IPPROTO_IPIP:
167 case IPPROTO_IPV6:
168 break;
169 default:
170 return TC_ACT_OK;
171 }
172
173 /* add L2 encap (if specified) */
174 switch (l2_proto) {
175 case ETH_P_MPLS_UC:
176 *((__u32 *)((__u8 *)&h_outer + olen)) = mpls_label;
177 break;
178 case ETH_P_TEB:
179 if (bpf_skb_load_bytes(skb, 0, (__u8 *)&h_outer + olen,
180 ETH_HLEN))
181 return TC_ACT_SHOT;
182 break;
183 }
184 olen += l2_len;
185
186 /* add room between mac and network header */
187 if (bpf_skb_adjust_room(skb, olen, BPF_ADJ_ROOM_MAC, flags))
188 return TC_ACT_SHOT;
189
190 /* prepare new outer network header */
191 h_outer.ip = iph_inner;
192 h_outer.ip.tot_len = bpf_htons(olen +
193 bpf_ntohs(h_outer.ip.tot_len));
194 h_outer.ip.protocol = encap_proto;
195
196 set_ipv4_csum((void *)&h_outer.ip);
197
198 /* store new outer network header */
199 if (bpf_skb_store_bytes(skb, ETH_HLEN, &h_outer, olen,
200 BPF_F_INVALIDATE_HASH) < 0)
201 return TC_ACT_SHOT;
202
203 /* if changing outer proto type, update eth->h_proto */
204 if (encap_proto == IPPROTO_IPV6) {
205 struct ethhdr eth;
206
207 if (bpf_skb_load_bytes(skb, 0, ð, sizeof(eth)) < 0)
208 return TC_ACT_SHOT;
209 eth.h_proto = bpf_htons(ETH_P_IP);
210 if (bpf_skb_store_bytes(skb, 0, ð, sizeof(eth), 0) < 0)
211 return TC_ACT_SHOT;
212 }
213
214 return TC_ACT_OK;
215}
216
217static __always_inline int encap_ipv6(struct __sk_buff *skb, __u8 encap_proto,
218 __u16 l2_proto)
219{
220 __u16 udp_dst = UDP_PORT;
221 struct ipv6hdr iph_inner;
222 struct v6hdr h_outer;
223 struct tcphdr tcph;
224 int olen, l2_len;
225 __u16 tot_len;
226 __u64 flags;
227
228 if (bpf_skb_load_bytes(skb, ETH_HLEN, &iph_inner,
229 sizeof(iph_inner)) < 0)
230 return TC_ACT_OK;
231
232 /* filter only packets we want */
233 if (bpf_skb_load_bytes(skb, ETH_HLEN + sizeof(iph_inner),
234 &tcph, sizeof(tcph)) < 0)
235 return TC_ACT_OK;
236
237 if (tcph.dest != __bpf_constant_htons(cfg_port))
238 return TC_ACT_OK;
239
240 olen = sizeof(h_outer.ip);
241 l2_len = 0;
242
243 flags = BPF_F_ADJ_ROOM_FIXED_GSO | BPF_F_ADJ_ROOM_ENCAP_L3_IPV6;
244
245 switch (l2_proto) {
246 case ETH_P_MPLS_UC:
247 l2_len = sizeof(mpls_label);
248 udp_dst = MPLS_OVER_UDP_PORT;
249 break;
250 case ETH_P_TEB:
251 l2_len = ETH_HLEN;
252 udp_dst = ETH_OVER_UDP_PORT;
253 break;
254 }
255 flags |= BPF_F_ADJ_ROOM_ENCAP_L2(l2_len);
256
257 switch (encap_proto) {
258 case IPPROTO_GRE:
259 flags |= BPF_F_ADJ_ROOM_ENCAP_L4_GRE;
260 olen += sizeof(h_outer.l4hdr.gre);
261 h_outer.l4hdr.gre.protocol = bpf_htons(l2_proto);
262 h_outer.l4hdr.gre.flags = 0;
263 break;
264 case IPPROTO_UDP:
265 flags |= BPF_F_ADJ_ROOM_ENCAP_L4_UDP;
266 olen += sizeof(h_outer.l4hdr.udp);
267 h_outer.l4hdr.udp.source = __bpf_constant_htons(cfg_udp_src);
268 h_outer.l4hdr.udp.dest = bpf_htons(udp_dst);
269 tot_len = bpf_ntohs(iph_inner.payload_len) + sizeof(iph_inner) +
270 sizeof(h_outer.l4hdr.udp);
271 h_outer.l4hdr.udp.check = 0;
272 h_outer.l4hdr.udp.len = bpf_htons(tot_len);
273 break;
274 case IPPROTO_IPV6:
275 break;
276 default:
277 return TC_ACT_OK;
278 }
279
280 /* add L2 encap (if specified) */
281 switch (l2_proto) {
282 case ETH_P_MPLS_UC:
283 *((__u32 *)((__u8 *)&h_outer + olen)) = mpls_label;
284 break;
285 case ETH_P_TEB:
286 if (bpf_skb_load_bytes(skb, 0, (__u8 *)&h_outer + olen,
287 ETH_HLEN))
288 return TC_ACT_SHOT;
289 break;
290 }
291 olen += l2_len;
292
293 /* add room between mac and network header */
294 if (bpf_skb_adjust_room(skb, olen, BPF_ADJ_ROOM_MAC, flags))
295 return TC_ACT_SHOT;
296
297 /* prepare new outer network header */
298 h_outer.ip = iph_inner;
299 h_outer.ip.payload_len = bpf_htons(olen +
300 bpf_ntohs(h_outer.ip.payload_len));
301
302 h_outer.ip.nexthdr = encap_proto;
303
304 /* store new outer network header */
305 if (bpf_skb_store_bytes(skb, ETH_HLEN, &h_outer, olen,
306 BPF_F_INVALIDATE_HASH) < 0)
307 return TC_ACT_SHOT;
308
309 return TC_ACT_OK;
310}
311
312SEC("encap_ipip_none")
313int __encap_ipip_none(struct __sk_buff *skb)
314{
315 if (skb->protocol == __bpf_constant_htons(ETH_P_IP))
316 return encap_ipv4(skb, IPPROTO_IPIP, ETH_P_IP);
317 else
318 return TC_ACT_OK;
319}
320
321SEC("encap_gre_none")
322int __encap_gre_none(struct __sk_buff *skb)
323{
324 if (skb->protocol == __bpf_constant_htons(ETH_P_IP))
325 return encap_ipv4(skb, IPPROTO_GRE, ETH_P_IP);
326 else
327 return TC_ACT_OK;
328}
329
330SEC("encap_gre_mpls")
331int __encap_gre_mpls(struct __sk_buff *skb)
332{
333 if (skb->protocol == __bpf_constant_htons(ETH_P_IP))
334 return encap_ipv4(skb, IPPROTO_GRE, ETH_P_MPLS_UC);
335 else
336 return TC_ACT_OK;
337}
338
339SEC("encap_gre_eth")
340int __encap_gre_eth(struct __sk_buff *skb)
341{
342 if (skb->protocol == __bpf_constant_htons(ETH_P_IP))
343 return encap_ipv4(skb, IPPROTO_GRE, ETH_P_TEB);
344 else
345 return TC_ACT_OK;
346}
347
348SEC("encap_udp_none")
349int __encap_udp_none(struct __sk_buff *skb)
350{
351 if (skb->protocol == __bpf_constant_htons(ETH_P_IP))
352 return encap_ipv4(skb, IPPROTO_UDP, ETH_P_IP);
353 else
354 return TC_ACT_OK;
355}
356
357SEC("encap_udp_mpls")
358int __encap_udp_mpls(struct __sk_buff *skb)
359{
360 if (skb->protocol == __bpf_constant_htons(ETH_P_IP))
361 return encap_ipv4(skb, IPPROTO_UDP, ETH_P_MPLS_UC);
362 else
363 return TC_ACT_OK;
364}
365
366SEC("encap_udp_eth")
367int __encap_udp_eth(struct __sk_buff *skb)
368{
369 if (skb->protocol == __bpf_constant_htons(ETH_P_IP))
370 return encap_ipv4(skb, IPPROTO_UDP, ETH_P_TEB);
371 else
372 return TC_ACT_OK;
373}
374
375SEC("encap_sit_none")
376int __encap_sit_none(struct __sk_buff *skb)
377{
378 if (skb->protocol == __bpf_constant_htons(ETH_P_IPV6))
379 return encap_ipv4(skb, IPPROTO_IPV6, ETH_P_IP);
380 else
381 return TC_ACT_OK;
382}
383
384SEC("encap_ip6tnl_none")
385int __encap_ip6tnl_none(struct __sk_buff *skb)
386{
387 if (skb->protocol == __bpf_constant_htons(ETH_P_IPV6))
388 return encap_ipv6(skb, IPPROTO_IPV6, ETH_P_IPV6);
389 else
390 return TC_ACT_OK;
391}
392
393SEC("encap_ip6gre_none")
394int __encap_ip6gre_none(struct __sk_buff *skb)
395{
396 if (skb->protocol == __bpf_constant_htons(ETH_P_IPV6))
397 return encap_ipv6(skb, IPPROTO_GRE, ETH_P_IPV6);
398 else
399 return TC_ACT_OK;
400}
401
402SEC("encap_ip6gre_mpls")
403int __encap_ip6gre_mpls(struct __sk_buff *skb)
404{
405 if (skb->protocol == __bpf_constant_htons(ETH_P_IPV6))
406 return encap_ipv6(skb, IPPROTO_GRE, ETH_P_MPLS_UC);
407 else
408 return TC_ACT_OK;
409}
410
411SEC("encap_ip6gre_eth")
412int __encap_ip6gre_eth(struct __sk_buff *skb)
413{
414 if (skb->protocol == __bpf_constant_htons(ETH_P_IPV6))
415 return encap_ipv6(skb, IPPROTO_GRE, ETH_P_TEB);
416 else
417 return TC_ACT_OK;
418}
419
420SEC("encap_ip6udp_none")
421int __encap_ip6udp_none(struct __sk_buff *skb)
422{
423 if (skb->protocol == __bpf_constant_htons(ETH_P_IPV6))
424 return encap_ipv6(skb, IPPROTO_UDP, ETH_P_IPV6);
425 else
426 return TC_ACT_OK;
427}
428
429SEC("encap_ip6udp_mpls")
430int __encap_ip6udp_mpls(struct __sk_buff *skb)
431{
432 if (skb->protocol == __bpf_constant_htons(ETH_P_IPV6))
433 return encap_ipv6(skb, IPPROTO_UDP, ETH_P_MPLS_UC);
434 else
435 return TC_ACT_OK;
436}
437
438SEC("encap_ip6udp_eth")
439int __encap_ip6udp_eth(struct __sk_buff *skb)
440{
441 if (skb->protocol == __bpf_constant_htons(ETH_P_IPV6))
442 return encap_ipv6(skb, IPPROTO_UDP, ETH_P_TEB);
443 else
444 return TC_ACT_OK;
445}
446
447static int decap_internal(struct __sk_buff *skb, int off, int len, char proto)
448{
449 char buf[sizeof(struct v6hdr)];
450 struct gre_hdr greh;
451 struct udphdr udph;
452 int olen = len;
453
454 switch (proto) {
455 case IPPROTO_IPIP:
456 case IPPROTO_IPV6:
457 break;
458 case IPPROTO_GRE:
459 olen += sizeof(struct gre_hdr);
460 if (bpf_skb_load_bytes(skb, off + len, &greh, sizeof(greh)) < 0)
461 return TC_ACT_OK;
462 switch (bpf_ntohs(greh.protocol)) {
463 case ETH_P_MPLS_UC:
464 olen += sizeof(mpls_label);
465 break;
466 case ETH_P_TEB:
467 olen += ETH_HLEN;
468 break;
469 }
470 break;
471 case IPPROTO_UDP:
472 olen += sizeof(struct udphdr);
473 if (bpf_skb_load_bytes(skb, off + len, &udph, sizeof(udph)) < 0)
474 return TC_ACT_OK;
475 switch (bpf_ntohs(udph.dest)) {
476 case MPLS_OVER_UDP_PORT:
477 olen += sizeof(mpls_label);
478 break;
479 case ETH_OVER_UDP_PORT:
480 olen += ETH_HLEN;
481 break;
482 }
483 break;
484 default:
485 return TC_ACT_OK;
486 }
487
488 if (bpf_skb_adjust_room(skb, -olen, BPF_ADJ_ROOM_MAC,
489 BPF_F_ADJ_ROOM_FIXED_GSO))
490 return TC_ACT_SHOT;
491
492 return TC_ACT_OK;
493}
494
495static int decap_ipv4(struct __sk_buff *skb)
496{
497 struct iphdr iph_outer;
498
499 if (bpf_skb_load_bytes(skb, ETH_HLEN, &iph_outer,
500 sizeof(iph_outer)) < 0)
501 return TC_ACT_OK;
502
503 if (iph_outer.ihl != 5)
504 return TC_ACT_OK;
505
506 return decap_internal(skb, ETH_HLEN, sizeof(iph_outer),
507 iph_outer.protocol);
508}
509
510static int decap_ipv6(struct __sk_buff *skb)
511{
512 struct ipv6hdr iph_outer;
513
514 if (bpf_skb_load_bytes(skb, ETH_HLEN, &iph_outer,
515 sizeof(iph_outer)) < 0)
516 return TC_ACT_OK;
517
518 return decap_internal(skb, ETH_HLEN, sizeof(iph_outer),
519 iph_outer.nexthdr);
520}
521
522SEC("decap")
523int decap_f(struct __sk_buff *skb)
524{
525 switch (skb->protocol) {
526 case __bpf_constant_htons(ETH_P_IP):
527 return decap_ipv4(skb);
528 case __bpf_constant_htons(ETH_P_IPV6):
529 return decap_ipv6(skb);
530 default:
531 /* does not match, ignore */
532 return TC_ACT_OK;
533 }
534}
535
536char __license[] SEC("license") = "GPL";
1// SPDX-License-Identifier: GPL-2.0
2
3/* In-place tunneling */
4
5#include <stdbool.h>
6#include <string.h>
7
8#include <linux/stddef.h>
9#include <linux/bpf.h>
10#include <linux/if_ether.h>
11#include <linux/in.h>
12#include <linux/ip.h>
13#include <linux/ipv6.h>
14#include <linux/mpls.h>
15#include <linux/tcp.h>
16#include <linux/udp.h>
17#include <linux/pkt_cls.h>
18#include <linux/types.h>
19
20#include <bpf/bpf_endian.h>
21#include <bpf/bpf_helpers.h>
22
23static const int cfg_port = 8000;
24
25static const int cfg_udp_src = 20000;
26
27#define L2_PAD_SZ (sizeof(struct vxlanhdr) + ETH_HLEN)
28
29#define UDP_PORT 5555
30#define MPLS_OVER_UDP_PORT 6635
31#define ETH_OVER_UDP_PORT 7777
32#define VXLAN_UDP_PORT 8472
33
34#define EXTPROTO_VXLAN 0x1
35
36#define VXLAN_N_VID (1u << 24)
37#define VXLAN_VNI_MASK bpf_htonl((VXLAN_N_VID - 1) << 8)
38#define VXLAN_FLAGS 0x8
39#define VXLAN_VNI 1
40
41#ifndef NEXTHDR_DEST
42#define NEXTHDR_DEST 60
43#endif
44
45/* MPLS label 1000 with S bit (last label) set and ttl of 255. */
46static const __u32 mpls_label = __bpf_constant_htonl(1000 << 12 |
47 MPLS_LS_S_MASK | 0xff);
48
49struct vxlanhdr {
50 __be32 vx_flags;
51 __be32 vx_vni;
52} __attribute__((packed));
53
54struct gre_hdr {
55 __be16 flags;
56 __be16 protocol;
57} __attribute__((packed));
58
59union l4hdr {
60 struct udphdr udp;
61 struct gre_hdr gre;
62};
63
64struct v4hdr {
65 struct iphdr ip;
66 union l4hdr l4hdr;
67 __u8 pad[L2_PAD_SZ]; /* space for L2 header / vxlan header ... */
68} __attribute__((packed));
69
70struct v6hdr {
71 struct ipv6hdr ip;
72 union l4hdr l4hdr;
73 __u8 pad[L2_PAD_SZ]; /* space for L2 header / vxlan header ... */
74} __attribute__((packed));
75
76static __always_inline void set_ipv4_csum(struct iphdr *iph)
77{
78 __u16 *iph16 = (__u16 *)iph;
79 __u32 csum;
80 int i;
81
82 iph->check = 0;
83
84#pragma clang loop unroll(full)
85 for (i = 0, csum = 0; i < sizeof(*iph) >> 1; i++)
86 csum += *iph16++;
87
88 iph->check = ~((csum & 0xffff) + (csum >> 16));
89}
90
91static __always_inline int __encap_ipv4(struct __sk_buff *skb, __u8 encap_proto,
92 __u16 l2_proto, __u16 ext_proto)
93{
94 __u16 udp_dst = UDP_PORT;
95 struct iphdr iph_inner;
96 struct v4hdr h_outer;
97 struct tcphdr tcph;
98 int olen, l2_len;
99 __u8 *l2_hdr = NULL;
100 int tcp_off;
101 __u64 flags;
102
103 /* Most tests encapsulate a packet into a tunnel with the same
104 * network protocol, and derive the outer header fields from
105 * the inner header.
106 *
107 * The 6in4 case tests different inner and outer protocols. As
108 * the inner is ipv6, but the outer expects an ipv4 header as
109 * input, manually build a struct iphdr based on the ipv6hdr.
110 */
111 if (encap_proto == IPPROTO_IPV6) {
112 const __u32 saddr = (192 << 24) | (168 << 16) | (1 << 8) | 1;
113 const __u32 daddr = (192 << 24) | (168 << 16) | (1 << 8) | 2;
114 struct ipv6hdr iph6_inner;
115
116 /* Read the IPv6 header */
117 if (bpf_skb_load_bytes(skb, ETH_HLEN, &iph6_inner,
118 sizeof(iph6_inner)) < 0)
119 return TC_ACT_OK;
120
121 /* Derive the IPv4 header fields from the IPv6 header */
122 memset(&iph_inner, 0, sizeof(iph_inner));
123 iph_inner.version = 4;
124 iph_inner.ihl = 5;
125 iph_inner.tot_len = bpf_htons(sizeof(iph6_inner) +
126 bpf_ntohs(iph6_inner.payload_len));
127 iph_inner.ttl = iph6_inner.hop_limit - 1;
128 iph_inner.protocol = iph6_inner.nexthdr;
129 iph_inner.saddr = __bpf_constant_htonl(saddr);
130 iph_inner.daddr = __bpf_constant_htonl(daddr);
131
132 tcp_off = sizeof(iph6_inner);
133 } else {
134 if (bpf_skb_load_bytes(skb, ETH_HLEN, &iph_inner,
135 sizeof(iph_inner)) < 0)
136 return TC_ACT_OK;
137
138 tcp_off = sizeof(iph_inner);
139 }
140
141 /* filter only packets we want */
142 if (iph_inner.ihl != 5 || iph_inner.protocol != IPPROTO_TCP)
143 return TC_ACT_OK;
144
145 if (bpf_skb_load_bytes(skb, ETH_HLEN + tcp_off,
146 &tcph, sizeof(tcph)) < 0)
147 return TC_ACT_OK;
148
149 if (tcph.dest != __bpf_constant_htons(cfg_port))
150 return TC_ACT_OK;
151
152 olen = sizeof(h_outer.ip);
153 l2_len = 0;
154
155 flags = BPF_F_ADJ_ROOM_FIXED_GSO | BPF_F_ADJ_ROOM_ENCAP_L3_IPV4;
156
157 switch (l2_proto) {
158 case ETH_P_MPLS_UC:
159 l2_len = sizeof(mpls_label);
160 udp_dst = MPLS_OVER_UDP_PORT;
161 break;
162 case ETH_P_TEB:
163 l2_len = ETH_HLEN;
164 if (ext_proto & EXTPROTO_VXLAN) {
165 udp_dst = VXLAN_UDP_PORT;
166 l2_len += sizeof(struct vxlanhdr);
167 } else
168 udp_dst = ETH_OVER_UDP_PORT;
169 break;
170 }
171 flags |= BPF_F_ADJ_ROOM_ENCAP_L2(l2_len);
172
173 switch (encap_proto) {
174 case IPPROTO_GRE:
175 flags |= BPF_F_ADJ_ROOM_ENCAP_L4_GRE;
176 olen += sizeof(h_outer.l4hdr.gre);
177 h_outer.l4hdr.gre.protocol = bpf_htons(l2_proto);
178 h_outer.l4hdr.gre.flags = 0;
179 break;
180 case IPPROTO_UDP:
181 flags |= BPF_F_ADJ_ROOM_ENCAP_L4_UDP;
182 olen += sizeof(h_outer.l4hdr.udp);
183 h_outer.l4hdr.udp.source = __bpf_constant_htons(cfg_udp_src);
184 h_outer.l4hdr.udp.dest = bpf_htons(udp_dst);
185 h_outer.l4hdr.udp.check = 0;
186 h_outer.l4hdr.udp.len = bpf_htons(bpf_ntohs(iph_inner.tot_len) +
187 sizeof(h_outer.l4hdr.udp) +
188 l2_len);
189 break;
190 case IPPROTO_IPIP:
191 case IPPROTO_IPV6:
192 break;
193 default:
194 return TC_ACT_OK;
195 }
196
197 /* add L2 encap (if specified) */
198 l2_hdr = (__u8 *)&h_outer + olen;
199 switch (l2_proto) {
200 case ETH_P_MPLS_UC:
201 *(__u32 *)l2_hdr = mpls_label;
202 break;
203 case ETH_P_TEB:
204 flags |= BPF_F_ADJ_ROOM_ENCAP_L2_ETH;
205
206 if (ext_proto & EXTPROTO_VXLAN) {
207 struct vxlanhdr *vxlan_hdr = (struct vxlanhdr *)l2_hdr;
208
209 vxlan_hdr->vx_flags = VXLAN_FLAGS;
210 vxlan_hdr->vx_vni = bpf_htonl((VXLAN_VNI & VXLAN_VNI_MASK) << 8);
211
212 l2_hdr += sizeof(struct vxlanhdr);
213 }
214
215 if (bpf_skb_load_bytes(skb, 0, l2_hdr, ETH_HLEN))
216 return TC_ACT_SHOT;
217
218 break;
219 }
220 olen += l2_len;
221
222 /* add room between mac and network header */
223 if (bpf_skb_adjust_room(skb, olen, BPF_ADJ_ROOM_MAC, flags))
224 return TC_ACT_SHOT;
225
226 /* prepare new outer network header */
227 h_outer.ip = iph_inner;
228 h_outer.ip.tot_len = bpf_htons(olen +
229 bpf_ntohs(h_outer.ip.tot_len));
230 h_outer.ip.protocol = encap_proto;
231
232 set_ipv4_csum((void *)&h_outer.ip);
233
234 /* store new outer network header */
235 if (bpf_skb_store_bytes(skb, ETH_HLEN, &h_outer, olen,
236 BPF_F_INVALIDATE_HASH) < 0)
237 return TC_ACT_SHOT;
238
239 /* if changing outer proto type, update eth->h_proto */
240 if (encap_proto == IPPROTO_IPV6) {
241 struct ethhdr eth;
242
243 if (bpf_skb_load_bytes(skb, 0, ð, sizeof(eth)) < 0)
244 return TC_ACT_SHOT;
245 eth.h_proto = bpf_htons(ETH_P_IP);
246 if (bpf_skb_store_bytes(skb, 0, ð, sizeof(eth), 0) < 0)
247 return TC_ACT_SHOT;
248 }
249
250 return TC_ACT_OK;
251}
252
253static __always_inline int encap_ipv4(struct __sk_buff *skb, __u8 encap_proto,
254 __u16 l2_proto)
255{
256 return __encap_ipv4(skb, encap_proto, l2_proto, 0);
257}
258
259static __always_inline int __encap_ipv6(struct __sk_buff *skb, __u8 encap_proto,
260 __u16 l2_proto, __u16 ext_proto)
261{
262 __u16 udp_dst = UDP_PORT;
263 struct ipv6hdr iph_inner;
264 struct v6hdr h_outer;
265 struct tcphdr tcph;
266 int olen, l2_len;
267 __u8 *l2_hdr = NULL;
268 __u16 tot_len;
269 __u64 flags;
270
271 if (bpf_skb_load_bytes(skb, ETH_HLEN, &iph_inner,
272 sizeof(iph_inner)) < 0)
273 return TC_ACT_OK;
274
275 /* filter only packets we want */
276 if (bpf_skb_load_bytes(skb, ETH_HLEN + sizeof(iph_inner),
277 &tcph, sizeof(tcph)) < 0)
278 return TC_ACT_OK;
279
280 if (tcph.dest != __bpf_constant_htons(cfg_port))
281 return TC_ACT_OK;
282
283 olen = sizeof(h_outer.ip);
284 l2_len = 0;
285
286 flags = BPF_F_ADJ_ROOM_FIXED_GSO | BPF_F_ADJ_ROOM_ENCAP_L3_IPV6;
287
288 switch (l2_proto) {
289 case ETH_P_MPLS_UC:
290 l2_len = sizeof(mpls_label);
291 udp_dst = MPLS_OVER_UDP_PORT;
292 break;
293 case ETH_P_TEB:
294 l2_len = ETH_HLEN;
295 if (ext_proto & EXTPROTO_VXLAN) {
296 udp_dst = VXLAN_UDP_PORT;
297 l2_len += sizeof(struct vxlanhdr);
298 } else
299 udp_dst = ETH_OVER_UDP_PORT;
300 break;
301 }
302 flags |= BPF_F_ADJ_ROOM_ENCAP_L2(l2_len);
303
304 switch (encap_proto) {
305 case IPPROTO_GRE:
306 flags |= BPF_F_ADJ_ROOM_ENCAP_L4_GRE;
307 olen += sizeof(h_outer.l4hdr.gre);
308 h_outer.l4hdr.gre.protocol = bpf_htons(l2_proto);
309 h_outer.l4hdr.gre.flags = 0;
310 break;
311 case IPPROTO_UDP:
312 flags |= BPF_F_ADJ_ROOM_ENCAP_L4_UDP;
313 olen += sizeof(h_outer.l4hdr.udp);
314 h_outer.l4hdr.udp.source = __bpf_constant_htons(cfg_udp_src);
315 h_outer.l4hdr.udp.dest = bpf_htons(udp_dst);
316 tot_len = bpf_ntohs(iph_inner.payload_len) + sizeof(iph_inner) +
317 sizeof(h_outer.l4hdr.udp) + l2_len;
318 h_outer.l4hdr.udp.check = 0;
319 h_outer.l4hdr.udp.len = bpf_htons(tot_len);
320 break;
321 case IPPROTO_IPV6:
322 break;
323 default:
324 return TC_ACT_OK;
325 }
326
327 /* add L2 encap (if specified) */
328 l2_hdr = (__u8 *)&h_outer + olen;
329 switch (l2_proto) {
330 case ETH_P_MPLS_UC:
331 *(__u32 *)l2_hdr = mpls_label;
332 break;
333 case ETH_P_TEB:
334 flags |= BPF_F_ADJ_ROOM_ENCAP_L2_ETH;
335
336 if (ext_proto & EXTPROTO_VXLAN) {
337 struct vxlanhdr *vxlan_hdr = (struct vxlanhdr *)l2_hdr;
338
339 vxlan_hdr->vx_flags = VXLAN_FLAGS;
340 vxlan_hdr->vx_vni = bpf_htonl((VXLAN_VNI & VXLAN_VNI_MASK) << 8);
341
342 l2_hdr += sizeof(struct vxlanhdr);
343 }
344
345 if (bpf_skb_load_bytes(skb, 0, l2_hdr, ETH_HLEN))
346 return TC_ACT_SHOT;
347 break;
348 }
349 olen += l2_len;
350
351 /* add room between mac and network header */
352 if (bpf_skb_adjust_room(skb, olen, BPF_ADJ_ROOM_MAC, flags))
353 return TC_ACT_SHOT;
354
355 /* prepare new outer network header */
356 h_outer.ip = iph_inner;
357 h_outer.ip.payload_len = bpf_htons(olen +
358 bpf_ntohs(h_outer.ip.payload_len));
359
360 h_outer.ip.nexthdr = encap_proto;
361
362 /* store new outer network header */
363 if (bpf_skb_store_bytes(skb, ETH_HLEN, &h_outer, olen,
364 BPF_F_INVALIDATE_HASH) < 0)
365 return TC_ACT_SHOT;
366
367 return TC_ACT_OK;
368}
369
370static int encap_ipv6_ipip6(struct __sk_buff *skb)
371{
372 struct iphdr iph_inner;
373 struct v6hdr h_outer;
374 struct tcphdr tcph;
375 struct ethhdr eth;
376 __u64 flags;
377 int olen;
378
379 if (bpf_skb_load_bytes(skb, ETH_HLEN, &iph_inner,
380 sizeof(iph_inner)) < 0)
381 return TC_ACT_OK;
382
383 /* filter only packets we want */
384 if (bpf_skb_load_bytes(skb, ETH_HLEN + (iph_inner.ihl << 2),
385 &tcph, sizeof(tcph)) < 0)
386 return TC_ACT_OK;
387
388 if (tcph.dest != __bpf_constant_htons(cfg_port))
389 return TC_ACT_OK;
390
391 olen = sizeof(h_outer.ip);
392
393 flags = BPF_F_ADJ_ROOM_FIXED_GSO | BPF_F_ADJ_ROOM_ENCAP_L3_IPV6;
394
395 /* add room between mac and network header */
396 if (bpf_skb_adjust_room(skb, olen, BPF_ADJ_ROOM_MAC, flags))
397 return TC_ACT_SHOT;
398
399 /* prepare new outer network header */
400 memset(&h_outer.ip, 0, sizeof(h_outer.ip));
401 h_outer.ip.version = 6;
402 h_outer.ip.hop_limit = iph_inner.ttl;
403 h_outer.ip.saddr.s6_addr[1] = 0xfd;
404 h_outer.ip.saddr.s6_addr[15] = 1;
405 h_outer.ip.daddr.s6_addr[1] = 0xfd;
406 h_outer.ip.daddr.s6_addr[15] = 2;
407 h_outer.ip.payload_len = iph_inner.tot_len;
408 h_outer.ip.nexthdr = IPPROTO_IPIP;
409
410 /* store new outer network header */
411 if (bpf_skb_store_bytes(skb, ETH_HLEN, &h_outer, olen,
412 BPF_F_INVALIDATE_HASH) < 0)
413 return TC_ACT_SHOT;
414
415 /* update eth->h_proto */
416 if (bpf_skb_load_bytes(skb, 0, ð, sizeof(eth)) < 0)
417 return TC_ACT_SHOT;
418 eth.h_proto = bpf_htons(ETH_P_IPV6);
419 if (bpf_skb_store_bytes(skb, 0, ð, sizeof(eth), 0) < 0)
420 return TC_ACT_SHOT;
421
422 return TC_ACT_OK;
423}
424
425static __always_inline int encap_ipv6(struct __sk_buff *skb, __u8 encap_proto,
426 __u16 l2_proto)
427{
428 return __encap_ipv6(skb, encap_proto, l2_proto, 0);
429}
430
431SEC("encap_ipip_none")
432int __encap_ipip_none(struct __sk_buff *skb)
433{
434 if (skb->protocol == __bpf_constant_htons(ETH_P_IP))
435 return encap_ipv4(skb, IPPROTO_IPIP, ETH_P_IP);
436 else
437 return TC_ACT_OK;
438}
439
440SEC("encap_gre_none")
441int __encap_gre_none(struct __sk_buff *skb)
442{
443 if (skb->protocol == __bpf_constant_htons(ETH_P_IP))
444 return encap_ipv4(skb, IPPROTO_GRE, ETH_P_IP);
445 else
446 return TC_ACT_OK;
447}
448
449SEC("encap_gre_mpls")
450int __encap_gre_mpls(struct __sk_buff *skb)
451{
452 if (skb->protocol == __bpf_constant_htons(ETH_P_IP))
453 return encap_ipv4(skb, IPPROTO_GRE, ETH_P_MPLS_UC);
454 else
455 return TC_ACT_OK;
456}
457
458SEC("encap_gre_eth")
459int __encap_gre_eth(struct __sk_buff *skb)
460{
461 if (skb->protocol == __bpf_constant_htons(ETH_P_IP))
462 return encap_ipv4(skb, IPPROTO_GRE, ETH_P_TEB);
463 else
464 return TC_ACT_OK;
465}
466
467SEC("encap_udp_none")
468int __encap_udp_none(struct __sk_buff *skb)
469{
470 if (skb->protocol == __bpf_constant_htons(ETH_P_IP))
471 return encap_ipv4(skb, IPPROTO_UDP, ETH_P_IP);
472 else
473 return TC_ACT_OK;
474}
475
476SEC("encap_udp_mpls")
477int __encap_udp_mpls(struct __sk_buff *skb)
478{
479 if (skb->protocol == __bpf_constant_htons(ETH_P_IP))
480 return encap_ipv4(skb, IPPROTO_UDP, ETH_P_MPLS_UC);
481 else
482 return TC_ACT_OK;
483}
484
485SEC("encap_udp_eth")
486int __encap_udp_eth(struct __sk_buff *skb)
487{
488 if (skb->protocol == __bpf_constant_htons(ETH_P_IP))
489 return encap_ipv4(skb, IPPROTO_UDP, ETH_P_TEB);
490 else
491 return TC_ACT_OK;
492}
493
494SEC("encap_vxlan_eth")
495int __encap_vxlan_eth(struct __sk_buff *skb)
496{
497 if (skb->protocol == __bpf_constant_htons(ETH_P_IP))
498 return __encap_ipv4(skb, IPPROTO_UDP,
499 ETH_P_TEB,
500 EXTPROTO_VXLAN);
501 else
502 return TC_ACT_OK;
503}
504
505SEC("encap_sit_none")
506int __encap_sit_none(struct __sk_buff *skb)
507{
508 if (skb->protocol == __bpf_constant_htons(ETH_P_IPV6))
509 return encap_ipv4(skb, IPPROTO_IPV6, ETH_P_IP);
510 else
511 return TC_ACT_OK;
512}
513
514SEC("encap_ip6tnl_none")
515int __encap_ip6tnl_none(struct __sk_buff *skb)
516{
517 if (skb->protocol == __bpf_constant_htons(ETH_P_IPV6))
518 return encap_ipv6(skb, IPPROTO_IPV6, ETH_P_IPV6);
519 else
520 return TC_ACT_OK;
521}
522
523SEC("encap_ipip6_none")
524int __encap_ipip6_none(struct __sk_buff *skb)
525{
526 if (skb->protocol == __bpf_constant_htons(ETH_P_IP))
527 return encap_ipv6_ipip6(skb);
528 else
529 return TC_ACT_OK;
530}
531
532SEC("encap_ip6gre_none")
533int __encap_ip6gre_none(struct __sk_buff *skb)
534{
535 if (skb->protocol == __bpf_constant_htons(ETH_P_IPV6))
536 return encap_ipv6(skb, IPPROTO_GRE, ETH_P_IPV6);
537 else
538 return TC_ACT_OK;
539}
540
541SEC("encap_ip6gre_mpls")
542int __encap_ip6gre_mpls(struct __sk_buff *skb)
543{
544 if (skb->protocol == __bpf_constant_htons(ETH_P_IPV6))
545 return encap_ipv6(skb, IPPROTO_GRE, ETH_P_MPLS_UC);
546 else
547 return TC_ACT_OK;
548}
549
550SEC("encap_ip6gre_eth")
551int __encap_ip6gre_eth(struct __sk_buff *skb)
552{
553 if (skb->protocol == __bpf_constant_htons(ETH_P_IPV6))
554 return encap_ipv6(skb, IPPROTO_GRE, ETH_P_TEB);
555 else
556 return TC_ACT_OK;
557}
558
559SEC("encap_ip6udp_none")
560int __encap_ip6udp_none(struct __sk_buff *skb)
561{
562 if (skb->protocol == __bpf_constant_htons(ETH_P_IPV6))
563 return encap_ipv6(skb, IPPROTO_UDP, ETH_P_IPV6);
564 else
565 return TC_ACT_OK;
566}
567
568SEC("encap_ip6udp_mpls")
569int __encap_ip6udp_mpls(struct __sk_buff *skb)
570{
571 if (skb->protocol == __bpf_constant_htons(ETH_P_IPV6))
572 return encap_ipv6(skb, IPPROTO_UDP, ETH_P_MPLS_UC);
573 else
574 return TC_ACT_OK;
575}
576
577SEC("encap_ip6udp_eth")
578int __encap_ip6udp_eth(struct __sk_buff *skb)
579{
580 if (skb->protocol == __bpf_constant_htons(ETH_P_IPV6))
581 return encap_ipv6(skb, IPPROTO_UDP, ETH_P_TEB);
582 else
583 return TC_ACT_OK;
584}
585
586SEC("encap_ip6vxlan_eth")
587int __encap_ip6vxlan_eth(struct __sk_buff *skb)
588{
589 if (skb->protocol == __bpf_constant_htons(ETH_P_IPV6))
590 return __encap_ipv6(skb, IPPROTO_UDP,
591 ETH_P_TEB,
592 EXTPROTO_VXLAN);
593 else
594 return TC_ACT_OK;
595}
596
597static int decap_internal(struct __sk_buff *skb, int off, int len, char proto)
598{
599 __u64 flags = BPF_F_ADJ_ROOM_FIXED_GSO;
600 struct ipv6_opt_hdr ip6_opt_hdr;
601 struct gre_hdr greh;
602 struct udphdr udph;
603 int olen = len;
604
605 switch (proto) {
606 case IPPROTO_IPIP:
607 flags |= BPF_F_ADJ_ROOM_DECAP_L3_IPV4;
608 break;
609 case IPPROTO_IPV6:
610 flags |= BPF_F_ADJ_ROOM_DECAP_L3_IPV6;
611 break;
612 case NEXTHDR_DEST:
613 if (bpf_skb_load_bytes(skb, off + len, &ip6_opt_hdr,
614 sizeof(ip6_opt_hdr)) < 0)
615 return TC_ACT_OK;
616 switch (ip6_opt_hdr.nexthdr) {
617 case IPPROTO_IPIP:
618 flags |= BPF_F_ADJ_ROOM_DECAP_L3_IPV4;
619 break;
620 case IPPROTO_IPV6:
621 flags |= BPF_F_ADJ_ROOM_DECAP_L3_IPV6;
622 break;
623 default:
624 return TC_ACT_OK;
625 }
626 break;
627 case IPPROTO_GRE:
628 olen += sizeof(struct gre_hdr);
629 if (bpf_skb_load_bytes(skb, off + len, &greh, sizeof(greh)) < 0)
630 return TC_ACT_OK;
631 switch (bpf_ntohs(greh.protocol)) {
632 case ETH_P_MPLS_UC:
633 olen += sizeof(mpls_label);
634 break;
635 case ETH_P_TEB:
636 olen += ETH_HLEN;
637 break;
638 }
639 break;
640 case IPPROTO_UDP:
641 olen += sizeof(struct udphdr);
642 if (bpf_skb_load_bytes(skb, off + len, &udph, sizeof(udph)) < 0)
643 return TC_ACT_OK;
644 switch (bpf_ntohs(udph.dest)) {
645 case MPLS_OVER_UDP_PORT:
646 olen += sizeof(mpls_label);
647 break;
648 case ETH_OVER_UDP_PORT:
649 olen += ETH_HLEN;
650 break;
651 case VXLAN_UDP_PORT:
652 olen += ETH_HLEN + sizeof(struct vxlanhdr);
653 break;
654 }
655 break;
656 default:
657 return TC_ACT_OK;
658 }
659
660 if (bpf_skb_adjust_room(skb, -olen, BPF_ADJ_ROOM_MAC, flags))
661 return TC_ACT_SHOT;
662
663 return TC_ACT_OK;
664}
665
666static int decap_ipv4(struct __sk_buff *skb)
667{
668 struct iphdr iph_outer;
669
670 if (bpf_skb_load_bytes(skb, ETH_HLEN, &iph_outer,
671 sizeof(iph_outer)) < 0)
672 return TC_ACT_OK;
673
674 if (iph_outer.ihl != 5)
675 return TC_ACT_OK;
676
677 return decap_internal(skb, ETH_HLEN, sizeof(iph_outer),
678 iph_outer.protocol);
679}
680
681static int decap_ipv6(struct __sk_buff *skb)
682{
683 struct ipv6hdr iph_outer;
684
685 if (bpf_skb_load_bytes(skb, ETH_HLEN, &iph_outer,
686 sizeof(iph_outer)) < 0)
687 return TC_ACT_OK;
688
689 return decap_internal(skb, ETH_HLEN, sizeof(iph_outer),
690 iph_outer.nexthdr);
691}
692
693SEC("decap")
694int decap_f(struct __sk_buff *skb)
695{
696 switch (skb->protocol) {
697 case __bpf_constant_htons(ETH_P_IP):
698 return decap_ipv4(skb);
699 case __bpf_constant_htons(ETH_P_IPV6):
700 return decap_ipv6(skb);
701 default:
702 /* does not match, ignore */
703 return TC_ACT_OK;
704 }
705}
706
707char __license[] SEC("license") = "GPL";