1 // SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
2 // Copyright (c) 2020 Cloudflare
3 
4 #include <errno.h>
5 #include <stdbool.h>
6 #include <stddef.h>
7 #include <linux/bpf.h>
8 #include <linux/in.h>
9 #include <sys/socket.h>
10 
11 #include <bpf/bpf_endian.h>
12 #include <bpf/bpf_helpers.h>
13 
14 #define IP4(a, b, c, d)					\
15 	bpf_htonl((((__u32)(a) & 0xffU) << 24) |	\
16 		  (((__u32)(b) & 0xffU) << 16) |	\
17 		  (((__u32)(c) & 0xffU) <<  8) |	\
18 		  (((__u32)(d) & 0xffU) <<  0))
19 #define IP6(aaaa, bbbb, cccc, dddd)			\
20 	{ bpf_htonl(aaaa), bpf_htonl(bbbb), bpf_htonl(cccc), bpf_htonl(dddd) }
21 
22 /* Macros for least-significant byte and word accesses. */
23 #if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
24 #define LSE_INDEX(index, size) (index)
25 #else
26 #define LSE_INDEX(index, size) ((size) - (index) - 1)
27 #endif
28 #define LSB(value, index)				\
29 	(((__u8 *)&(value))[LSE_INDEX((index), sizeof(value))])
30 #define LSW(value, index)				\
31 	(((__u16 *)&(value))[LSE_INDEX((index), sizeof(value) / 2)])
32 
33 #define MAX_SOCKS 32
34 
35 struct {
36 	__uint(type, BPF_MAP_TYPE_SOCKMAP);
37 	__uint(max_entries, MAX_SOCKS);
38 	__type(key, __u32);
39 	__type(value, __u64);
40 } redir_map SEC(".maps");
41 
42 struct {
43 	__uint(type, BPF_MAP_TYPE_ARRAY);
44 	__uint(max_entries, 2);
45 	__type(key, int);
46 	__type(value, int);
47 } run_map SEC(".maps");
48 
49 enum {
50 	PROG1 = 0,
51 	PROG2,
52 };
53 
54 enum {
55 	SERVER_A = 0,
56 	SERVER_B,
57 };
58 
59 /* Addressable key/value constants for convenience */
60 static const int KEY_PROG1 = PROG1;
61 static const int KEY_PROG2 = PROG2;
62 static const int PROG_DONE = 1;
63 
64 static const __u32 KEY_SERVER_A = SERVER_A;
65 static const __u32 KEY_SERVER_B = SERVER_B;
66 
67 static const __u16 SRC_PORT = bpf_htons(8008);
68 static const __u32 SRC_IP4 = IP4(127, 0, 0, 2);
69 static const __u32 SRC_IP6[] = IP6(0xfd000000, 0x0, 0x0, 0x00000002);
70 
71 static const __u16 DST_PORT = 7007; /* Host byte order */
72 static const __u32 DST_IP4 = IP4(127, 0, 0, 1);
73 static const __u32 DST_IP6[] = IP6(0xfd000000, 0x0, 0x0, 0x00000001);
74 
75 SEC("sk_lookup/lookup_pass")
lookup_pass(struct bpf_sk_lookup * ctx)76 int lookup_pass(struct bpf_sk_lookup *ctx)
77 {
78 	return SK_PASS;
79 }
80 
81 SEC("sk_lookup/lookup_drop")
lookup_drop(struct bpf_sk_lookup * ctx)82 int lookup_drop(struct bpf_sk_lookup *ctx)
83 {
84 	return SK_DROP;
85 }
86 
87 SEC("sk_reuseport/reuse_pass")
reuseport_pass(struct sk_reuseport_md * ctx)88 int reuseport_pass(struct sk_reuseport_md *ctx)
89 {
90 	return SK_PASS;
91 }
92 
93 SEC("sk_reuseport/reuse_drop")
reuseport_drop(struct sk_reuseport_md * ctx)94 int reuseport_drop(struct sk_reuseport_md *ctx)
95 {
96 	return SK_DROP;
97 }
98 
99 /* Redirect packets destined for port DST_PORT to socket at redir_map[0]. */
100 SEC("sk_lookup/redir_port")
redir_port(struct bpf_sk_lookup * ctx)101 int redir_port(struct bpf_sk_lookup *ctx)
102 {
103 	struct bpf_sock *sk;
104 	int err;
105 
106 	if (ctx->local_port != DST_PORT)
107 		return SK_PASS;
108 
109 	sk = bpf_map_lookup_elem(&redir_map, &KEY_SERVER_A);
110 	if (!sk)
111 		return SK_PASS;
112 
113 	err = bpf_sk_assign(ctx, sk, 0);
114 	bpf_sk_release(sk);
115 	return err ? SK_DROP : SK_PASS;
116 }
117 
118 /* Redirect packets destined for DST_IP4 address to socket at redir_map[0]. */
119 SEC("sk_lookup/redir_ip4")
redir_ip4(struct bpf_sk_lookup * ctx)120 int redir_ip4(struct bpf_sk_lookup *ctx)
121 {
122 	struct bpf_sock *sk;
123 	int err;
124 
125 	if (ctx->family != AF_INET)
126 		return SK_PASS;
127 	if (ctx->local_port != DST_PORT)
128 		return SK_PASS;
129 	if (ctx->local_ip4 != DST_IP4)
130 		return SK_PASS;
131 
132 	sk = bpf_map_lookup_elem(&redir_map, &KEY_SERVER_A);
133 	if (!sk)
134 		return SK_PASS;
135 
136 	err = bpf_sk_assign(ctx, sk, 0);
137 	bpf_sk_release(sk);
138 	return err ? SK_DROP : SK_PASS;
139 }
140 
141 /* Redirect packets destined for DST_IP6 address to socket at redir_map[0]. */
142 SEC("sk_lookup/redir_ip6")
redir_ip6(struct bpf_sk_lookup * ctx)143 int redir_ip6(struct bpf_sk_lookup *ctx)
144 {
145 	struct bpf_sock *sk;
146 	int err;
147 
148 	if (ctx->family != AF_INET6)
149 		return SK_PASS;
150 	if (ctx->local_port != DST_PORT)
151 		return SK_PASS;
152 	if (ctx->local_ip6[0] != DST_IP6[0] ||
153 	    ctx->local_ip6[1] != DST_IP6[1] ||
154 	    ctx->local_ip6[2] != DST_IP6[2] ||
155 	    ctx->local_ip6[3] != DST_IP6[3])
156 		return SK_PASS;
157 
158 	sk = bpf_map_lookup_elem(&redir_map, &KEY_SERVER_A);
159 	if (!sk)
160 		return SK_PASS;
161 
162 	err = bpf_sk_assign(ctx, sk, 0);
163 	bpf_sk_release(sk);
164 	return err ? SK_DROP : SK_PASS;
165 }
166 
167 SEC("sk_lookup/select_sock_a")
select_sock_a(struct bpf_sk_lookup * ctx)168 int select_sock_a(struct bpf_sk_lookup *ctx)
169 {
170 	struct bpf_sock *sk;
171 	int err;
172 
173 	sk = bpf_map_lookup_elem(&redir_map, &KEY_SERVER_A);
174 	if (!sk)
175 		return SK_PASS;
176 
177 	err = bpf_sk_assign(ctx, sk, 0);
178 	bpf_sk_release(sk);
179 	return err ? SK_DROP : SK_PASS;
180 }
181 
182 SEC("sk_lookup/select_sock_a_no_reuseport")
select_sock_a_no_reuseport(struct bpf_sk_lookup * ctx)183 int select_sock_a_no_reuseport(struct bpf_sk_lookup *ctx)
184 {
185 	struct bpf_sock *sk;
186 	int err;
187 
188 	sk = bpf_map_lookup_elem(&redir_map, &KEY_SERVER_A);
189 	if (!sk)
190 		return SK_DROP;
191 
192 	err = bpf_sk_assign(ctx, sk, BPF_SK_LOOKUP_F_NO_REUSEPORT);
193 	bpf_sk_release(sk);
194 	return err ? SK_DROP : SK_PASS;
195 }
196 
197 SEC("sk_reuseport/select_sock_b")
select_sock_b(struct sk_reuseport_md * ctx)198 int select_sock_b(struct sk_reuseport_md *ctx)
199 {
200 	__u32 key = KEY_SERVER_B;
201 	int err;
202 
203 	err = bpf_sk_select_reuseport(ctx, &redir_map, &key, 0);
204 	return err ? SK_DROP : SK_PASS;
205 }
206 
207 /* Check that bpf_sk_assign() returns -EEXIST if socket already selected. */
208 SEC("sk_lookup/sk_assign_eexist")
sk_assign_eexist(struct bpf_sk_lookup * ctx)209 int sk_assign_eexist(struct bpf_sk_lookup *ctx)
210 {
211 	struct bpf_sock *sk;
212 	int err, ret;
213 
214 	ret = SK_DROP;
215 	sk = bpf_map_lookup_elem(&redir_map, &KEY_SERVER_B);
216 	if (!sk)
217 		goto out;
218 	err = bpf_sk_assign(ctx, sk, 0);
219 	if (err)
220 		goto out;
221 	bpf_sk_release(sk);
222 
223 	sk = bpf_map_lookup_elem(&redir_map, &KEY_SERVER_A);
224 	if (!sk)
225 		goto out;
226 	err = bpf_sk_assign(ctx, sk, 0);
227 	if (err != -EEXIST) {
228 		bpf_printk("sk_assign returned %d, expected %d\n",
229 			   err, -EEXIST);
230 		goto out;
231 	}
232 
233 	ret = SK_PASS; /* Success, redirect to KEY_SERVER_B */
234 out:
235 	if (sk)
236 		bpf_sk_release(sk);
237 	return ret;
238 }
239 
240 /* Check that bpf_sk_assign(BPF_SK_LOOKUP_F_REPLACE) can override selection. */
241 SEC("sk_lookup/sk_assign_replace_flag")
sk_assign_replace_flag(struct bpf_sk_lookup * ctx)242 int sk_assign_replace_flag(struct bpf_sk_lookup *ctx)
243 {
244 	struct bpf_sock *sk;
245 	int err, ret;
246 
247 	ret = SK_DROP;
248 	sk = bpf_map_lookup_elem(&redir_map, &KEY_SERVER_A);
249 	if (!sk)
250 		goto out;
251 	err = bpf_sk_assign(ctx, sk, 0);
252 	if (err)
253 		goto out;
254 	bpf_sk_release(sk);
255 
256 	sk = bpf_map_lookup_elem(&redir_map, &KEY_SERVER_B);
257 	if (!sk)
258 		goto out;
259 	err = bpf_sk_assign(ctx, sk, BPF_SK_LOOKUP_F_REPLACE);
260 	if (err) {
261 		bpf_printk("sk_assign returned %d, expected 0\n", err);
262 		goto out;
263 	}
264 
265 	ret = SK_PASS; /* Success, redirect to KEY_SERVER_B */
266 out:
267 	if (sk)
268 		bpf_sk_release(sk);
269 	return ret;
270 }
271 
272 /* Check that bpf_sk_assign(sk=NULL) is accepted. */
273 SEC("sk_lookup/sk_assign_null")
sk_assign_null(struct bpf_sk_lookup * ctx)274 int sk_assign_null(struct bpf_sk_lookup *ctx)
275 {
276 	struct bpf_sock *sk = NULL;
277 	int err, ret;
278 
279 	ret = SK_DROP;
280 
281 	err = bpf_sk_assign(ctx, NULL, 0);
282 	if (err) {
283 		bpf_printk("sk_assign returned %d, expected 0\n", err);
284 		goto out;
285 	}
286 
287 	sk = bpf_map_lookup_elem(&redir_map, &KEY_SERVER_B);
288 	if (!sk)
289 		goto out;
290 	err = bpf_sk_assign(ctx, sk, BPF_SK_LOOKUP_F_REPLACE);
291 	if (err) {
292 		bpf_printk("sk_assign returned %d, expected 0\n", err);
293 		goto out;
294 	}
295 
296 	if (ctx->sk != sk)
297 		goto out;
298 	err = bpf_sk_assign(ctx, NULL, 0);
299 	if (err != -EEXIST)
300 		goto out;
301 	err = bpf_sk_assign(ctx, NULL, BPF_SK_LOOKUP_F_REPLACE);
302 	if (err)
303 		goto out;
304 	err = bpf_sk_assign(ctx, sk, BPF_SK_LOOKUP_F_REPLACE);
305 	if (err)
306 		goto out;
307 
308 	ret = SK_PASS; /* Success, redirect to KEY_SERVER_B */
309 out:
310 	if (sk)
311 		bpf_sk_release(sk);
312 	return ret;
313 }
314 
315 /* Check that selected sk is accessible through context. */
316 SEC("sk_lookup/access_ctx_sk")
access_ctx_sk(struct bpf_sk_lookup * ctx)317 int access_ctx_sk(struct bpf_sk_lookup *ctx)
318 {
319 	struct bpf_sock *sk1 = NULL, *sk2 = NULL;
320 	int err, ret;
321 
322 	ret = SK_DROP;
323 
324 	/* Try accessing unassigned (NULL) ctx->sk field */
325 	if (ctx->sk && ctx->sk->family != AF_INET)
326 		goto out;
327 
328 	/* Assign a value to ctx->sk */
329 	sk1 = bpf_map_lookup_elem(&redir_map, &KEY_SERVER_A);
330 	if (!sk1)
331 		goto out;
332 	err = bpf_sk_assign(ctx, sk1, 0);
333 	if (err)
334 		goto out;
335 	if (ctx->sk != sk1)
336 		goto out;
337 
338 	/* Access ctx->sk fields */
339 	if (ctx->sk->family != AF_INET ||
340 	    ctx->sk->type != SOCK_STREAM ||
341 	    ctx->sk->state != BPF_TCP_LISTEN)
342 		goto out;
343 
344 	/* Reset selection */
345 	err = bpf_sk_assign(ctx, NULL, BPF_SK_LOOKUP_F_REPLACE);
346 	if (err)
347 		goto out;
348 	if (ctx->sk)
349 		goto out;
350 
351 	/* Assign another socket */
352 	sk2 = bpf_map_lookup_elem(&redir_map, &KEY_SERVER_B);
353 	if (!sk2)
354 		goto out;
355 	err = bpf_sk_assign(ctx, sk2, BPF_SK_LOOKUP_F_REPLACE);
356 	if (err)
357 		goto out;
358 	if (ctx->sk != sk2)
359 		goto out;
360 
361 	/* Access reassigned ctx->sk fields */
362 	if (ctx->sk->family != AF_INET ||
363 	    ctx->sk->type != SOCK_STREAM ||
364 	    ctx->sk->state != BPF_TCP_LISTEN)
365 		goto out;
366 
367 	ret = SK_PASS; /* Success, redirect to KEY_SERVER_B */
368 out:
369 	if (sk1)
370 		bpf_sk_release(sk1);
371 	if (sk2)
372 		bpf_sk_release(sk2);
373 	return ret;
374 }
375 
376 /* Check narrow loads from ctx fields that support them.
377  *
378  * Narrow loads of size >= target field size from a non-zero offset
379  * are not covered because they give bogus results, that is the
380  * verifier ignores the offset.
381  */
382 SEC("sk_lookup/ctx_narrow_access")
ctx_narrow_access(struct bpf_sk_lookup * ctx)383 int ctx_narrow_access(struct bpf_sk_lookup *ctx)
384 {
385 	struct bpf_sock *sk;
386 	int err, family;
387 	bool v4;
388 
389 	v4 = (ctx->family == AF_INET);
390 
391 	/* Narrow loads from family field */
392 	if (LSB(ctx->family, 0) != (v4 ? AF_INET : AF_INET6) ||
393 	    LSB(ctx->family, 1) != 0 || LSB(ctx->family, 2) != 0 || LSB(ctx->family, 3) != 0)
394 		return SK_DROP;
395 	if (LSW(ctx->family, 0) != (v4 ? AF_INET : AF_INET6))
396 		return SK_DROP;
397 
398 	/* Narrow loads from protocol field */
399 	if (LSB(ctx->protocol, 0) != IPPROTO_TCP ||
400 	    LSB(ctx->protocol, 1) != 0 || LSB(ctx->protocol, 2) != 0 || LSB(ctx->protocol, 3) != 0)
401 		return SK_DROP;
402 	if (LSW(ctx->protocol, 0) != IPPROTO_TCP)
403 		return SK_DROP;
404 
405 	/* Narrow loads from remote_port field. Expect SRC_PORT. */
406 	if (LSB(ctx->remote_port, 0) != ((SRC_PORT >> 0) & 0xff) ||
407 	    LSB(ctx->remote_port, 1) != ((SRC_PORT >> 8) & 0xff) ||
408 	    LSB(ctx->remote_port, 2) != 0 || LSB(ctx->remote_port, 3) != 0)
409 		return SK_DROP;
410 	if (LSW(ctx->remote_port, 0) != SRC_PORT)
411 		return SK_DROP;
412 
413 	/* Narrow loads from local_port field. Expect DST_PORT. */
414 	if (LSB(ctx->local_port, 0) != ((DST_PORT >> 0) & 0xff) ||
415 	    LSB(ctx->local_port, 1) != ((DST_PORT >> 8) & 0xff) ||
416 	    LSB(ctx->local_port, 2) != 0 || LSB(ctx->local_port, 3) != 0)
417 		return SK_DROP;
418 	if (LSW(ctx->local_port, 0) != DST_PORT)
419 		return SK_DROP;
420 
421 	/* Narrow loads from IPv4 fields */
422 	if (v4) {
423 		/* Expect SRC_IP4 in remote_ip4 */
424 		if (LSB(ctx->remote_ip4, 0) != ((SRC_IP4 >> 0) & 0xff) ||
425 		    LSB(ctx->remote_ip4, 1) != ((SRC_IP4 >> 8) & 0xff) ||
426 		    LSB(ctx->remote_ip4, 2) != ((SRC_IP4 >> 16) & 0xff) ||
427 		    LSB(ctx->remote_ip4, 3) != ((SRC_IP4 >> 24) & 0xff))
428 			return SK_DROP;
429 		if (LSW(ctx->remote_ip4, 0) != ((SRC_IP4 >> 0) & 0xffff) ||
430 		    LSW(ctx->remote_ip4, 1) != ((SRC_IP4 >> 16) & 0xffff))
431 			return SK_DROP;
432 
433 		/* Expect DST_IP4 in local_ip4 */
434 		if (LSB(ctx->local_ip4, 0) != ((DST_IP4 >> 0) & 0xff) ||
435 		    LSB(ctx->local_ip4, 1) != ((DST_IP4 >> 8) & 0xff) ||
436 		    LSB(ctx->local_ip4, 2) != ((DST_IP4 >> 16) & 0xff) ||
437 		    LSB(ctx->local_ip4, 3) != ((DST_IP4 >> 24) & 0xff))
438 			return SK_DROP;
439 		if (LSW(ctx->local_ip4, 0) != ((DST_IP4 >> 0) & 0xffff) ||
440 		    LSW(ctx->local_ip4, 1) != ((DST_IP4 >> 16) & 0xffff))
441 			return SK_DROP;
442 	} else {
443 		/* Expect 0.0.0.0 IPs when family != AF_INET */
444 		if (LSB(ctx->remote_ip4, 0) != 0 || LSB(ctx->remote_ip4, 1) != 0 ||
445 		    LSB(ctx->remote_ip4, 2) != 0 || LSB(ctx->remote_ip4, 3) != 0)
446 			return SK_DROP;
447 		if (LSW(ctx->remote_ip4, 0) != 0 || LSW(ctx->remote_ip4, 1) != 0)
448 			return SK_DROP;
449 
450 		if (LSB(ctx->local_ip4, 0) != 0 || LSB(ctx->local_ip4, 1) != 0 ||
451 		    LSB(ctx->local_ip4, 2) != 0 || LSB(ctx->local_ip4, 3) != 0)
452 			return SK_DROP;
453 		if (LSW(ctx->local_ip4, 0) != 0 || LSW(ctx->local_ip4, 1) != 0)
454 			return SK_DROP;
455 	}
456 
457 	/* Narrow loads from IPv6 fields */
458 	if (!v4) {
459 		/* Expect SRC_IP6 in remote_ip6 */
460 		if (LSB(ctx->remote_ip6[0], 0) != ((SRC_IP6[0] >> 0) & 0xff) ||
461 		    LSB(ctx->remote_ip6[0], 1) != ((SRC_IP6[0] >> 8) & 0xff) ||
462 		    LSB(ctx->remote_ip6[0], 2) != ((SRC_IP6[0] >> 16) & 0xff) ||
463 		    LSB(ctx->remote_ip6[0], 3) != ((SRC_IP6[0] >> 24) & 0xff) ||
464 		    LSB(ctx->remote_ip6[1], 0) != ((SRC_IP6[1] >> 0) & 0xff) ||
465 		    LSB(ctx->remote_ip6[1], 1) != ((SRC_IP6[1] >> 8) & 0xff) ||
466 		    LSB(ctx->remote_ip6[1], 2) != ((SRC_IP6[1] >> 16) & 0xff) ||
467 		    LSB(ctx->remote_ip6[1], 3) != ((SRC_IP6[1] >> 24) & 0xff) ||
468 		    LSB(ctx->remote_ip6[2], 0) != ((SRC_IP6[2] >> 0) & 0xff) ||
469 		    LSB(ctx->remote_ip6[2], 1) != ((SRC_IP6[2] >> 8) & 0xff) ||
470 		    LSB(ctx->remote_ip6[2], 2) != ((SRC_IP6[2] >> 16) & 0xff) ||
471 		    LSB(ctx->remote_ip6[2], 3) != ((SRC_IP6[2] >> 24) & 0xff) ||
472 		    LSB(ctx->remote_ip6[3], 0) != ((SRC_IP6[3] >> 0) & 0xff) ||
473 		    LSB(ctx->remote_ip6[3], 1) != ((SRC_IP6[3] >> 8) & 0xff) ||
474 		    LSB(ctx->remote_ip6[3], 2) != ((SRC_IP6[3] >> 16) & 0xff) ||
475 		    LSB(ctx->remote_ip6[3], 3) != ((SRC_IP6[3] >> 24) & 0xff))
476 			return SK_DROP;
477 		if (LSW(ctx->remote_ip6[0], 0) != ((SRC_IP6[0] >> 0) & 0xffff) ||
478 		    LSW(ctx->remote_ip6[0], 1) != ((SRC_IP6[0] >> 16) & 0xffff) ||
479 		    LSW(ctx->remote_ip6[1], 0) != ((SRC_IP6[1] >> 0) & 0xffff) ||
480 		    LSW(ctx->remote_ip6[1], 1) != ((SRC_IP6[1] >> 16) & 0xffff) ||
481 		    LSW(ctx->remote_ip6[2], 0) != ((SRC_IP6[2] >> 0) & 0xffff) ||
482 		    LSW(ctx->remote_ip6[2], 1) != ((SRC_IP6[2] >> 16) & 0xffff) ||
483 		    LSW(ctx->remote_ip6[3], 0) != ((SRC_IP6[3] >> 0) & 0xffff) ||
484 		    LSW(ctx->remote_ip6[3], 1) != ((SRC_IP6[3] >> 16) & 0xffff))
485 			return SK_DROP;
486 		/* Expect DST_IP6 in local_ip6 */
487 		if (LSB(ctx->local_ip6[0], 0) != ((DST_IP6[0] >> 0) & 0xff) ||
488 		    LSB(ctx->local_ip6[0], 1) != ((DST_IP6[0] >> 8) & 0xff) ||
489 		    LSB(ctx->local_ip6[0], 2) != ((DST_IP6[0] >> 16) & 0xff) ||
490 		    LSB(ctx->local_ip6[0], 3) != ((DST_IP6[0] >> 24) & 0xff) ||
491 		    LSB(ctx->local_ip6[1], 0) != ((DST_IP6[1] >> 0) & 0xff) ||
492 		    LSB(ctx->local_ip6[1], 1) != ((DST_IP6[1] >> 8) & 0xff) ||
493 		    LSB(ctx->local_ip6[1], 2) != ((DST_IP6[1] >> 16) & 0xff) ||
494 		    LSB(ctx->local_ip6[1], 3) != ((DST_IP6[1] >> 24) & 0xff) ||
495 		    LSB(ctx->local_ip6[2], 0) != ((DST_IP6[2] >> 0) & 0xff) ||
496 		    LSB(ctx->local_ip6[2], 1) != ((DST_IP6[2] >> 8) & 0xff) ||
497 		    LSB(ctx->local_ip6[2], 2) != ((DST_IP6[2] >> 16) & 0xff) ||
498 		    LSB(ctx->local_ip6[2], 3) != ((DST_IP6[2] >> 24) & 0xff) ||
499 		    LSB(ctx->local_ip6[3], 0) != ((DST_IP6[3] >> 0) & 0xff) ||
500 		    LSB(ctx->local_ip6[3], 1) != ((DST_IP6[3] >> 8) & 0xff) ||
501 		    LSB(ctx->local_ip6[3], 2) != ((DST_IP6[3] >> 16) & 0xff) ||
502 		    LSB(ctx->local_ip6[3], 3) != ((DST_IP6[3] >> 24) & 0xff))
503 			return SK_DROP;
504 		if (LSW(ctx->local_ip6[0], 0) != ((DST_IP6[0] >> 0) & 0xffff) ||
505 		    LSW(ctx->local_ip6[0], 1) != ((DST_IP6[0] >> 16) & 0xffff) ||
506 		    LSW(ctx->local_ip6[1], 0) != ((DST_IP6[1] >> 0) & 0xffff) ||
507 		    LSW(ctx->local_ip6[1], 1) != ((DST_IP6[1] >> 16) & 0xffff) ||
508 		    LSW(ctx->local_ip6[2], 0) != ((DST_IP6[2] >> 0) & 0xffff) ||
509 		    LSW(ctx->local_ip6[2], 1) != ((DST_IP6[2] >> 16) & 0xffff) ||
510 		    LSW(ctx->local_ip6[3], 0) != ((DST_IP6[3] >> 0) & 0xffff) ||
511 		    LSW(ctx->local_ip6[3], 1) != ((DST_IP6[3] >> 16) & 0xffff))
512 			return SK_DROP;
513 	} else {
514 		/* Expect :: IPs when family != AF_INET6 */
515 		if (LSB(ctx->remote_ip6[0], 0) != 0 || LSB(ctx->remote_ip6[0], 1) != 0 ||
516 		    LSB(ctx->remote_ip6[0], 2) != 0 || LSB(ctx->remote_ip6[0], 3) != 0 ||
517 		    LSB(ctx->remote_ip6[1], 0) != 0 || LSB(ctx->remote_ip6[1], 1) != 0 ||
518 		    LSB(ctx->remote_ip6[1], 2) != 0 || LSB(ctx->remote_ip6[1], 3) != 0 ||
519 		    LSB(ctx->remote_ip6[2], 0) != 0 || LSB(ctx->remote_ip6[2], 1) != 0 ||
520 		    LSB(ctx->remote_ip6[2], 2) != 0 || LSB(ctx->remote_ip6[2], 3) != 0 ||
521 		    LSB(ctx->remote_ip6[3], 0) != 0 || LSB(ctx->remote_ip6[3], 1) != 0 ||
522 		    LSB(ctx->remote_ip6[3], 2) != 0 || LSB(ctx->remote_ip6[3], 3) != 0)
523 			return SK_DROP;
524 		if (LSW(ctx->remote_ip6[0], 0) != 0 || LSW(ctx->remote_ip6[0], 1) != 0 ||
525 		    LSW(ctx->remote_ip6[1], 0) != 0 || LSW(ctx->remote_ip6[1], 1) != 0 ||
526 		    LSW(ctx->remote_ip6[2], 0) != 0 || LSW(ctx->remote_ip6[2], 1) != 0 ||
527 		    LSW(ctx->remote_ip6[3], 0) != 0 || LSW(ctx->remote_ip6[3], 1) != 0)
528 			return SK_DROP;
529 
530 		if (LSB(ctx->local_ip6[0], 0) != 0 || LSB(ctx->local_ip6[0], 1) != 0 ||
531 		    LSB(ctx->local_ip6[0], 2) != 0 || LSB(ctx->local_ip6[0], 3) != 0 ||
532 		    LSB(ctx->local_ip6[1], 0) != 0 || LSB(ctx->local_ip6[1], 1) != 0 ||
533 		    LSB(ctx->local_ip6[1], 2) != 0 || LSB(ctx->local_ip6[1], 3) != 0 ||
534 		    LSB(ctx->local_ip6[2], 0) != 0 || LSB(ctx->local_ip6[2], 1) != 0 ||
535 		    LSB(ctx->local_ip6[2], 2) != 0 || LSB(ctx->local_ip6[2], 3) != 0 ||
536 		    LSB(ctx->local_ip6[3], 0) != 0 || LSB(ctx->local_ip6[3], 1) != 0 ||
537 		    LSB(ctx->local_ip6[3], 2) != 0 || LSB(ctx->local_ip6[3], 3) != 0)
538 			return SK_DROP;
539 		if (LSW(ctx->remote_ip6[0], 0) != 0 || LSW(ctx->remote_ip6[0], 1) != 0 ||
540 		    LSW(ctx->remote_ip6[1], 0) != 0 || LSW(ctx->remote_ip6[1], 1) != 0 ||
541 		    LSW(ctx->remote_ip6[2], 0) != 0 || LSW(ctx->remote_ip6[2], 1) != 0 ||
542 		    LSW(ctx->remote_ip6[3], 0) != 0 || LSW(ctx->remote_ip6[3], 1) != 0)
543 			return SK_DROP;
544 	}
545 
546 	/* Success, redirect to KEY_SERVER_B */
547 	sk = bpf_map_lookup_elem(&redir_map, &KEY_SERVER_B);
548 	if (sk) {
549 		bpf_sk_assign(ctx, sk, 0);
550 		bpf_sk_release(sk);
551 	}
552 	return SK_PASS;
553 }
554 
555 /* Check that sk_assign rejects SERVER_A socket with -ESOCKNOSUPPORT */
556 SEC("sk_lookup/sk_assign_esocknosupport")
sk_assign_esocknosupport(struct bpf_sk_lookup * ctx)557 int sk_assign_esocknosupport(struct bpf_sk_lookup *ctx)
558 {
559 	struct bpf_sock *sk;
560 	int err, ret;
561 
562 	ret = SK_DROP;
563 	sk = bpf_map_lookup_elem(&redir_map, &KEY_SERVER_A);
564 	if (!sk)
565 		goto out;
566 
567 	err = bpf_sk_assign(ctx, sk, 0);
568 	if (err != -ESOCKTNOSUPPORT) {
569 		bpf_printk("sk_assign returned %d, expected %d\n",
570 			   err, -ESOCKTNOSUPPORT);
571 		goto out;
572 	}
573 
574 	ret = SK_PASS; /* Success, pass to regular lookup */
575 out:
576 	if (sk)
577 		bpf_sk_release(sk);
578 	return ret;
579 }
580 
581 SEC("sk_lookup/multi_prog_pass1")
multi_prog_pass1(struct bpf_sk_lookup * ctx)582 int multi_prog_pass1(struct bpf_sk_lookup *ctx)
583 {
584 	bpf_map_update_elem(&run_map, &KEY_PROG1, &PROG_DONE, BPF_ANY);
585 	return SK_PASS;
586 }
587 
588 SEC("sk_lookup/multi_prog_pass2")
multi_prog_pass2(struct bpf_sk_lookup * ctx)589 int multi_prog_pass2(struct bpf_sk_lookup *ctx)
590 {
591 	bpf_map_update_elem(&run_map, &KEY_PROG2, &PROG_DONE, BPF_ANY);
592 	return SK_PASS;
593 }
594 
595 SEC("sk_lookup/multi_prog_drop1")
multi_prog_drop1(struct bpf_sk_lookup * ctx)596 int multi_prog_drop1(struct bpf_sk_lookup *ctx)
597 {
598 	bpf_map_update_elem(&run_map, &KEY_PROG1, &PROG_DONE, BPF_ANY);
599 	return SK_DROP;
600 }
601 
602 SEC("sk_lookup/multi_prog_drop2")
multi_prog_drop2(struct bpf_sk_lookup * ctx)603 int multi_prog_drop2(struct bpf_sk_lookup *ctx)
604 {
605 	bpf_map_update_elem(&run_map, &KEY_PROG2, &PROG_DONE, BPF_ANY);
606 	return SK_DROP;
607 }
608 
select_server_a(struct bpf_sk_lookup * ctx)609 static __always_inline int select_server_a(struct bpf_sk_lookup *ctx)
610 {
611 	struct bpf_sock *sk;
612 	int err;
613 
614 	sk = bpf_map_lookup_elem(&redir_map, &KEY_SERVER_A);
615 	if (!sk)
616 		return SK_DROP;
617 
618 	err = bpf_sk_assign(ctx, sk, 0);
619 	bpf_sk_release(sk);
620 	if (err)
621 		return SK_DROP;
622 
623 	return SK_PASS;
624 }
625 
626 SEC("sk_lookup/multi_prog_redir1")
multi_prog_redir1(struct bpf_sk_lookup * ctx)627 int multi_prog_redir1(struct bpf_sk_lookup *ctx)
628 {
629 	int ret;
630 
631 	ret = select_server_a(ctx);
632 	bpf_map_update_elem(&run_map, &KEY_PROG1, &PROG_DONE, BPF_ANY);
633 	return SK_PASS;
634 }
635 
636 SEC("sk_lookup/multi_prog_redir2")
multi_prog_redir2(struct bpf_sk_lookup * ctx)637 int multi_prog_redir2(struct bpf_sk_lookup *ctx)
638 {
639 	int ret;
640 
641 	ret = select_server_a(ctx);
642 	bpf_map_update_elem(&run_map, &KEY_PROG2, &PROG_DONE, BPF_ANY);
643 	return SK_PASS;
644 }
645 
646 char _license[] SEC("license") = "Dual BSD/GPL";
647 __u32 _version SEC("version") = 1;
648