1 files changed, 665 insertions, 0 deletions

diff --git a/tools/testing/selftests/bpf/progs/test_sk_lookup.c b/tools/testing/selftests/bpf/progs/test_sk_lookup.c
new file mode 100644
index 000000000000..6058dcb11b36
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/test_sk_lookup.c
@@ -0,0 +1,665 @@
+// SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
+// Copyright (c) 2020 Cloudflare
+
+#include <errno.h>
+#include <stdbool.h>
+#include <stddef.h>
+#include <linux/bpf.h>
+#include <linux/in.h>
+#include <sys/socket.h>
+
+#include <bpf/bpf_endian.h>
+#include <bpf/bpf_helpers.h>
+
+#define IP4(a, b, c, d)					\
+	bpf_htonl((((__u32)(a) & 0xffU) << 24) |	\
+		  (((__u32)(b) & 0xffU) << 16) |	\
+		  (((__u32)(c) & 0xffU) <<  8) |	\
+		  (((__u32)(d) & 0xffU) <<  0))
+#define IP6(aaaa, bbbb, cccc, dddd)			\
+	{ bpf_htonl(aaaa), bpf_htonl(bbbb), bpf_htonl(cccc), bpf_htonl(dddd) }
+
+/* Macros for least-significant byte and word accesses. */
+#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
+#define LSE_INDEX(index, size) (index)
+#else
+#define LSE_INDEX(index, size) ((size) - (index) - 1)
+#endif
+#define LSB(value, index)				\
+	(((__u8 *)&(value))[LSE_INDEX((index), sizeof(value))])
+#define LSW(value, index)				\
+	(((__u16 *)&(value))[LSE_INDEX((index), sizeof(value) / 2)])
+
+#define MAX_SOCKS 32
+
+struct {
+	__uint(type, BPF_MAP_TYPE_SOCKMAP);
+	__uint(max_entries, MAX_SOCKS);
+	__type(key, __u32);
+	__type(value, __u64);
+} redir_map SEC(".maps");
+
+struct {
+	__uint(type, BPF_MAP_TYPE_ARRAY);
+	__uint(max_entries, 2);
+	__type(key, int);
+	__type(value, int);
+} run_map SEC(".maps");
+
+enum {
+	PROG1 = 0,
+	PROG2,
+};
+
+enum {
+	SERVER_A = 0,
+	SERVER_B,
+};
+
+/* Addressable key/value constants for convenience */
+static const int KEY_PROG1 = PROG1;
+static const int KEY_PROG2 = PROG2;
+static const int PROG_DONE = 1;
+
+static const __u32 KEY_SERVER_A = SERVER_A;
+static const __u32 KEY_SERVER_B = SERVER_B;
+
+static const __u16 SRC_PORT = bpf_htons(8008);
+static const __u32 SRC_IP4 = IP4(127, 0, 0, 2);
+static const __u32 SRC_IP6[] = IP6(0xfd000000, 0x0, 0x0, 0x00000002);
+
+static const __u16 DST_PORT = 7007; /* Host byte order */
+static const __u32 DST_IP4 = IP4(127, 0, 0, 1);
+static const __u32 DST_IP6[] = IP6(0xfd000000, 0x0, 0x0, 0x00000001);
+
+SEC("sk_lookup")
+int lookup_pass(struct bpf_sk_lookup *ctx)
+{
+	return SK_PASS;
+}
+
+SEC("sk_lookup")
+int lookup_drop(struct bpf_sk_lookup *ctx)
+{
+	return SK_DROP;
+}
+
+SEC("sk_lookup")
+int check_ifindex(struct bpf_sk_lookup *ctx)
+{
+	if (ctx->ingress_ifindex == 1)
+		return SK_DROP;
+	return SK_PASS;
+}
+
+SEC("sk_reuseport")
+int reuseport_pass(struct sk_reuseport_md *ctx)
+{
+	return SK_PASS;
+}
+
+SEC("sk_reuseport")
+int reuseport_drop(struct sk_reuseport_md *ctx)
+{
+	return SK_DROP;
+}
+
+/* Redirect packets destined for port DST_PORT to socket at redir_map[0]. */
+SEC("sk_lookup")
+int redir_port(struct bpf_sk_lookup *ctx)
+{
+	struct bpf_sock *sk;
+	int err;
+
+	if (ctx->local_port != DST_PORT)
+		return SK_PASS;
+
+	sk = bpf_map_lookup_elem(&redir_map, &KEY_SERVER_A);
+	if (!sk)
+		return SK_PASS;
+
+	err = bpf_sk_assign(ctx, sk, 0);
+	bpf_sk_release(sk);
+	return err ? SK_DROP : SK_PASS;
+}
+
+/* Redirect packets destined for DST_IP4 address to socket at redir_map[0]. */
+SEC("sk_lookup")
+int redir_ip4(struct bpf_sk_lookup *ctx)
+{
+	struct bpf_sock *sk;
+	int err;
+
+	if (ctx->family != AF_INET)
+		return SK_PASS;
+	if (ctx->local_port != DST_PORT)
+		return SK_PASS;
+	if (ctx->local_ip4 != DST_IP4)
+		return SK_PASS;
+
+	sk = bpf_map_lookup_elem(&redir_map, &KEY_SERVER_A);
+	if (!sk)
+		return SK_PASS;
+
+	err = bpf_sk_assign(ctx, sk, 0);
+	bpf_sk_release(sk);
+	return err ? SK_DROP : SK_PASS;
+}
+
+/* Redirect packets destined for DST_IP6 address to socket at redir_map[0]. */
+SEC("sk_lookup")
+int redir_ip6(struct bpf_sk_lookup *ctx)
+{
+	struct bpf_sock *sk;
+	int err;
+
+	if (ctx->family != AF_INET6)
+		return SK_PASS;
+	if (ctx->local_port != DST_PORT)
+		return SK_PASS;
+	if (ctx->local_ip6[0] != DST_IP6[0] ||
+	    ctx->local_ip6[1] != DST_IP6[1] ||
+	    ctx->local_ip6[2] != DST_IP6[2] ||
+	    ctx->local_ip6[3] != DST_IP6[3])
+		return SK_PASS;
+
+	sk = bpf_map_lookup_elem(&redir_map, &KEY_SERVER_A);
+	if (!sk)
+		return SK_PASS;
+
+	err = bpf_sk_assign(ctx, sk, 0);
+	bpf_sk_release(sk);
+	return err ? SK_DROP : SK_PASS;
+}
+
+SEC("sk_lookup")
+int select_sock_a(struct bpf_sk_lookup *ctx)
+{
+	struct bpf_sock *sk;
+	int err;
+
+	sk = bpf_map_lookup_elem(&redir_map, &KEY_SERVER_A);
+	if (!sk)
+		return SK_PASS;
+
+	err = bpf_sk_assign(ctx, sk, 0);
+	bpf_sk_release(sk);
+	return err ? SK_DROP : SK_PASS;
+}
+
+SEC("sk_lookup")
+int select_sock_a_no_reuseport(struct bpf_sk_lookup *ctx)
+{
+	struct bpf_sock *sk;
+	int err;
+
+	sk = bpf_map_lookup_elem(&redir_map, &KEY_SERVER_A);
+	if (!sk)
+		return SK_DROP;
+
+	err = bpf_sk_assign(ctx, sk, BPF_SK_LOOKUP_F_NO_REUSEPORT);
+	bpf_sk_release(sk);
+	return err ? SK_DROP : SK_PASS;
+}
+
+SEC("sk_reuseport")
+int select_sock_b(struct sk_reuseport_md *ctx)
+{
+	__u32 key = KEY_SERVER_B;
+	int err;
+
+	err = bpf_sk_select_reuseport(ctx, &redir_map, &key, 0);
+	return err ? SK_DROP : SK_PASS;
+}
+
+/* Check that bpf_sk_assign() returns -EEXIST if socket already selected. */
+SEC("sk_lookup")
+int sk_assign_eexist(struct bpf_sk_lookup *ctx)
+{
+	struct bpf_sock *sk;
+	int err, ret;
+
+	ret = SK_DROP;
+	sk = bpf_map_lookup_elem(&redir_map, &KEY_SERVER_B);
+	if (!sk)
+		goto out;
+	err = bpf_sk_assign(ctx, sk, 0);
+	if (err)
+		goto out;
+	bpf_sk_release(sk);
+
+	sk = bpf_map_lookup_elem(&redir_map, &KEY_SERVER_A);
+	if (!sk)
+		goto out;
+	err = bpf_sk_assign(ctx, sk, 0);
+	if (err != -EEXIST) {
+		bpf_printk("sk_assign returned %d, expected %d\n",
+			   err, -EEXIST);
+		goto out;
+	}
+
+	ret = SK_PASS; /* Success, redirect to KEY_SERVER_B */
+out:
+	if (sk)
+		bpf_sk_release(sk);
+	return ret;
+}
+
+/* Check that bpf_sk_assign(BPF_SK_LOOKUP_F_REPLACE) can override selection. */
+SEC("sk_lookup")
+int sk_assign_replace_flag(struct bpf_sk_lookup *ctx)
+{
+	struct bpf_sock *sk;
+	int err, ret;
+
+	ret = SK_DROP;
+	sk = bpf_map_lookup_elem(&redir_map, &KEY_SERVER_A);
+	if (!sk)
+		goto out;
+	err = bpf_sk_assign(ctx, sk, 0);
+	if (err)
+		goto out;
+	bpf_sk_release(sk);
+
+	sk = bpf_map_lookup_elem(&redir_map, &KEY_SERVER_B);
+	if (!sk)
+		goto out;
+	err = bpf_sk_assign(ctx, sk, BPF_SK_LOOKUP_F_REPLACE);
+	if (err) {
+		bpf_printk("sk_assign returned %d, expected 0\n", err);
+		goto out;
+	}
+
+	ret = SK_PASS; /* Success, redirect to KEY_SERVER_B */
+out:
+	if (sk)
+		bpf_sk_release(sk);
+	return ret;
+}
+
+/* Check that bpf_sk_assign(sk=NULL) is accepted. */
+SEC("sk_lookup")
+int sk_assign_null(struct bpf_sk_lookup *ctx)
+{
+	struct bpf_sock *sk = NULL;
+	int err, ret;
+
+	ret = SK_DROP;
+
+	err = bpf_sk_assign(ctx, NULL, 0);
+	if (err) {
+		bpf_printk("sk_assign returned %d, expected 0\n", err);
+		goto out;
+	}
+
+	sk = bpf_map_lookup_elem(&redir_map, &KEY_SERVER_B);
+	if (!sk)
+		goto out;
+	err = bpf_sk_assign(ctx, sk, BPF_SK_LOOKUP_F_REPLACE);
+	if (err) {
+		bpf_printk("sk_assign returned %d, expected 0\n", err);
+		goto out;
+	}
+
+	if (ctx->sk != sk)
+		goto out;
+	err = bpf_sk_assign(ctx, NULL, 0);
+	if (err != -EEXIST)
+		goto out;
+	err = bpf_sk_assign(ctx, NULL, BPF_SK_LOOKUP_F_REPLACE);
+	if (err)
+		goto out;
+	err = bpf_sk_assign(ctx, sk, BPF_SK_LOOKUP_F_REPLACE);
+	if (err)
+		goto out;
+
+	ret = SK_PASS; /* Success, redirect to KEY_SERVER_B */
+out:
+	if (sk)
+		bpf_sk_release(sk);
+	return ret;
+}
+
+/* Check that selected sk is accessible through context. */
+SEC("sk_lookup")
+int access_ctx_sk(struct bpf_sk_lookup *ctx)
+{
+	struct bpf_sock *sk1 = NULL, *sk2 = NULL;
+	int err, ret;
+
+	ret = SK_DROP;
+
+	/* Try accessing unassigned (NULL) ctx->sk field */
+	if (ctx->sk && ctx->sk->family != AF_INET)
+		goto out;
+
+	/* Assign a value to ctx->sk */
+	sk1 = bpf_map_lookup_elem(&redir_map, &KEY_SERVER_A);
+	if (!sk1)
+		goto out;
+	err = bpf_sk_assign(ctx, sk1, 0);
+	if (err)
+		goto out;
+	if (ctx->sk != sk1)
+		goto out;
+
+	/* Access ctx->sk fields */
+	if (ctx->sk->family != AF_INET ||
+	    ctx->sk->type != SOCK_STREAM ||
+	    ctx->sk->state != BPF_TCP_LISTEN)
+		goto out;
+
+	/* Reset selection */
+	err = bpf_sk_assign(ctx, NULL, BPF_SK_LOOKUP_F_REPLACE);
+	if (err)
+		goto out;
+	if (ctx->sk)
+		goto out;
+
+	/* Assign another socket */
+	sk2 = bpf_map_lookup_elem(&redir_map, &KEY_SERVER_B);
+	if (!sk2)
+		goto out;
+	err = bpf_sk_assign(ctx, sk2, BPF_SK_LOOKUP_F_REPLACE);
+	if (err)
+		goto out;
+	if (ctx->sk != sk2)
+		goto out;
+
+	/* Access reassigned ctx->sk fields */
+	if (ctx->sk->family != AF_INET ||
+	    ctx->sk->type != SOCK_STREAM ||
+	    ctx->sk->state != BPF_TCP_LISTEN)
+		goto out;
+
+	ret = SK_PASS; /* Success, redirect to KEY_SERVER_B */
+out:
+	if (sk1)
+		bpf_sk_release(sk1);
+	if (sk2)
+		bpf_sk_release(sk2);
+	return ret;
+}
+
+/* Check narrow loads from ctx fields that support them.
+ *
+ * Narrow loads of size >= target field size from a non-zero offset
+ * are not covered because they give bogus results, that is the
+ * verifier ignores the offset.
+ */
+SEC("sk_lookup")
+int ctx_narrow_access(struct bpf_sk_lookup *ctx)
+{
+	struct bpf_sock *sk;
+	int err, family;
+	__u32 val_u32;
+	bool v4;
+
+	v4 = (ctx->family == AF_INET);
+
+	/* Narrow loads from family field */
+	if (LSB(ctx->family, 0) != (v4 ? AF_INET : AF_INET6) ||
+	    LSB(ctx->family, 1) != 0 || LSB(ctx->family, 2) != 0 || LSB(ctx->family, 3) != 0)
+		return SK_DROP;
+	if (LSW(ctx->family, 0) != (v4 ? AF_INET : AF_INET6))
+		return SK_DROP;
+
+	/* Narrow loads from protocol field */
+	if (LSB(ctx->protocol, 0) != IPPROTO_TCP ||
+	    LSB(ctx->protocol, 1) != 0 || LSB(ctx->protocol, 2) != 0 || LSB(ctx->protocol, 3) != 0)
+		return SK_DROP;
+	if (LSW(ctx->protocol, 0) != IPPROTO_TCP)
+		return SK_DROP;
+
+	/* Narrow loads from remote_port field. Expect SRC_PORT. */
+	if (LSB(ctx->remote_port, 0) != ((SRC_PORT >> 0) & 0xff) ||
+	    LSB(ctx->remote_port, 1) != ((SRC_PORT >> 8) & 0xff))
+		return SK_DROP;
+	if (LSW(ctx->remote_port, 0) != SRC_PORT)
+		return SK_DROP;
+
+	/*
+	 * NOTE: 4-byte load from bpf_sk_lookup at remote_port offset
+	 * is quirky. It gets rewritten by the access converter to a
+	 * 2-byte load for backward compatibility. Treating the load
+	 * result as a be16 value makes the code portable across
+	 * little- and big-endian platforms.
+	 */
+	val_u32 = *(__u32 *)&ctx->remote_port;
+	if (val_u32 != SRC_PORT)
+		return SK_DROP;
+
+	/* Narrow loads from local_port field. Expect DST_PORT. */
+	if (LSB(ctx->local_port, 0) != ((DST_PORT >> 0) & 0xff) ||
+	    LSB(ctx->local_port, 1) != ((DST_PORT >> 8) & 0xff) ||
+	    LSB(ctx->local_port, 2) != 0 || LSB(ctx->local_port, 3) != 0)
+		return SK_DROP;
+	if (LSW(ctx->local_port, 0) != DST_PORT)
+		return SK_DROP;
+
+	/* Narrow loads from IPv4 fields */
+	if (v4) {
+		/* Expect SRC_IP4 in remote_ip4 */
+		if (LSB(ctx->remote_ip4, 0) != ((SRC_IP4 >> 0) & 0xff) ||
+		    LSB(ctx->remote_ip4, 1) != ((SRC_IP4 >> 8) & 0xff) ||
+		    LSB(ctx->remote_ip4, 2) != ((SRC_IP4 >> 16) & 0xff) ||
+		    LSB(ctx->remote_ip4, 3) != ((SRC_IP4 >> 24) & 0xff))
+			return SK_DROP;
+		if (LSW(ctx->remote_ip4, 0) != ((SRC_IP4 >> 0) & 0xffff) ||
+		    LSW(ctx->remote_ip4, 1) != ((SRC_IP4 >> 16) & 0xffff))
+			return SK_DROP;
+
+		/* Expect DST_IP4 in local_ip4 */
+		if (LSB(ctx->local_ip4, 0) != ((DST_IP4 >> 0) & 0xff) ||
+		    LSB(ctx->local_ip4, 1) != ((DST_IP4 >> 8) & 0xff) ||
+		    LSB(ctx->local_ip4, 2) != ((DST_IP4 >> 16) & 0xff) ||
+		    LSB(ctx->local_ip4, 3) != ((DST_IP4 >> 24) & 0xff))
+			return SK_DROP;
+		if (LSW(ctx->local_ip4, 0) != ((DST_IP4 >> 0) & 0xffff) ||
+		    LSW(ctx->local_ip4, 1) != ((DST_IP4 >> 16) & 0xffff))
+			return SK_DROP;
+	} else {
+		/* Expect 0.0.0.0 IPs when family != AF_INET */
+		if (LSB(ctx->remote_ip4, 0) != 0 || LSB(ctx->remote_ip4, 1) != 0 ||
+		    LSB(ctx->remote_ip4, 2) != 0 || LSB(ctx->remote_ip4, 3) != 0)
+			return SK_DROP;
+		if (LSW(ctx->remote_ip4, 0) != 0 || LSW(ctx->remote_ip4, 1) != 0)
+			return SK_DROP;
+
+		if (LSB(ctx->local_ip4, 0) != 0 || LSB(ctx->local_ip4, 1) != 0 ||
+		    LSB(ctx->local_ip4, 2) != 0 || LSB(ctx->local_ip4, 3) != 0)
+			return SK_DROP;
+		if (LSW(ctx->local_ip4, 0) != 0 || LSW(ctx->local_ip4, 1) != 0)
+			return SK_DROP;
+	}
+
+	/* Narrow loads from IPv6 fields */
+	if (!v4) {
+		/* Expect SRC_IP6 in remote_ip6 */
+		if (LSB(ctx->remote_ip6[0], 0) != ((SRC_IP6[0] >> 0) & 0xff) ||
+		    LSB(ctx->remote_ip6[0], 1) != ((SRC_IP6[0] >> 8) & 0xff) ||
+		    LSB(ctx->remote_ip6[0], 2) != ((SRC_IP6[0] >> 16) & 0xff) ||
+		    LSB(ctx->remote_ip6[0], 3) != ((SRC_IP6[0] >> 24) & 0xff) ||
+		    LSB(ctx->remote_ip6[1], 0) != ((SRC_IP6[1] >> 0) & 0xff) ||
+		    LSB(ctx->remote_ip6[1], 1) != ((SRC_IP6[1] >> 8) & 0xff) ||
+		    LSB(ctx->remote_ip6[1], 2) != ((SRC_IP6[1] >> 16) & 0xff) ||
+		    LSB(ctx->remote_ip6[1], 3) != ((SRC_IP6[1] >> 24) & 0xff) ||
+		    LSB(ctx->remote_ip6[2], 0) != ((SRC_IP6[2] >> 0) & 0xff) ||
+		    LSB(ctx->remote_ip6[2], 1) != ((SRC_IP6[2] >> 8) & 0xff) ||
+		    LSB(ctx->remote_ip6[2], 2) != ((SRC_IP6[2] >> 16) & 0xff) ||
+		    LSB(ctx->remote_ip6[2], 3) != ((SRC_IP6[2] >> 24) & 0xff) ||
+		    LSB(ctx->remote_ip6[3], 0) != ((SRC_IP6[3] >> 0) & 0xff) ||
+		    LSB(ctx->remote_ip6[3], 1) != ((SRC_IP6[3] >> 8) & 0xff) ||
+		    LSB(ctx->remote_ip6[3], 2) != ((SRC_IP6[3] >> 16) & 0xff) ||
+		    LSB(ctx->remote_ip6[3], 3) != ((SRC_IP6[3] >> 24) & 0xff))
+			return SK_DROP;
+		if (LSW(ctx->remote_ip6[0], 0) != ((SRC_IP6[0] >> 0) & 0xffff) ||
+		    LSW(ctx->remote_ip6[0], 1) != ((SRC_IP6[0] >> 16) & 0xffff) ||
+		    LSW(ctx->remote_ip6[1], 0) != ((SRC_IP6[1] >> 0) & 0xffff) ||
+		    LSW(ctx->remote_ip6[1], 1) != ((SRC_IP6[1] >> 16) & 0xffff) ||
+		    LSW(ctx->remote_ip6[2], 0) != ((SRC_IP6[2] >> 0) & 0xffff) ||
+		    LSW(ctx->remote_ip6[2], 1) != ((SRC_IP6[2] >> 16) & 0xffff) ||
+		    LSW(ctx->remote_ip6[3], 0) != ((SRC_IP6[3] >> 0) & 0xffff) ||
+		    LSW(ctx->remote_ip6[3], 1) != ((SRC_IP6[3] >> 16) & 0xffff))
+			return SK_DROP;
+		/* Expect DST_IP6 in local_ip6 */
+		if (LSB(ctx->local_ip6[0], 0) != ((DST_IP6[0] >> 0) & 0xff) ||
+		    LSB(ctx->local_ip6[0], 1) != ((DST_IP6[0] >> 8) & 0xff) ||
+		    LSB(ctx->local_ip6[0], 2) != ((DST_IP6[0] >> 16) & 0xff) ||
+		    LSB(ctx->local_ip6[0], 3) != ((DST_IP6[0] >> 24) & 0xff) ||
+		    LSB(ctx->local_ip6[1], 0) != ((DST_IP6[1] >> 0) & 0xff) ||
+		    LSB(ctx->local_ip6[1], 1) != ((DST_IP6[1] >> 8) & 0xff) ||
+		    LSB(ctx->local_ip6[1], 2) != ((DST_IP6[1] >> 16) & 0xff) ||
+		    LSB(ctx->local_ip6[1], 3) != ((DST_IP6[1] >> 24) & 0xff) ||
+		    LSB(ctx->local_ip6[2], 0) != ((DST_IP6[2] >> 0) & 0xff) ||
+		    LSB(ctx->local_ip6[2], 1) != ((DST_IP6[2] >> 8) & 0xff) ||
+		    LSB(ctx->local_ip6[2], 2) != ((DST_IP6[2] >> 16) & 0xff) ||
+		    LSB(ctx->local_ip6[2], 3) != ((DST_IP6[2] >> 24) & 0xff) ||
+		    LSB(ctx->local_ip6[3], 0) != ((DST_IP6[3] >> 0) & 0xff) ||
+		    LSB(ctx->local_ip6[3], 1) != ((DST_IP6[3] >> 8) & 0xff) ||
+		    LSB(ctx->local_ip6[3], 2) != ((DST_IP6[3] >> 16) & 0xff) ||
+		    LSB(ctx->local_ip6[3], 3) != ((DST_IP6[3] >> 24) & 0xff))
+			return SK_DROP;
+		if (LSW(ctx->local_ip6[0], 0) != ((DST_IP6[0] >> 0) & 0xffff) ||
+		    LSW(ctx->local_ip6[0], 1) != ((DST_IP6[0] >> 16) & 0xffff) ||
+		    LSW(ctx->local_ip6[1], 0) != ((DST_IP6[1] >> 0) & 0xffff) ||
+		    LSW(ctx->local_ip6[1], 1) != ((DST_IP6[1] >> 16) & 0xffff) ||
+		    LSW(ctx->local_ip6[2], 0) != ((DST_IP6[2] >> 0) & 0xffff) ||
+		    LSW(ctx->local_ip6[2], 1) != ((DST_IP6[2] >> 16) & 0xffff) ||
+		    LSW(ctx->local_ip6[3], 0) != ((DST_IP6[3] >> 0) & 0xffff) ||
+		    LSW(ctx->local_ip6[3], 1) != ((DST_IP6[3] >> 16) & 0xffff))
+			return SK_DROP;
+	} else {
+		/* Expect :: IPs when family != AF_INET6 */
+		if (LSB(ctx->remote_ip6[0], 0) != 0 || LSB(ctx->remote_ip6[0], 1) != 0 ||
+		    LSB(ctx->remote_ip6[0], 2) != 0 || LSB(ctx->remote_ip6[0], 3) != 0 ||
+		    LSB(ctx->remote_ip6[1], 0) != 0 || LSB(ctx->remote_ip6[1], 1) != 0 ||
+		    LSB(ctx->remote_ip6[1], 2) != 0 || LSB(ctx->remote_ip6[1], 3) != 0 ||
+		    LSB(ctx->remote_ip6[2], 0) != 0 || LSB(ctx->remote_ip6[2], 1) != 0 ||
+		    LSB(ctx->remote_ip6[2], 2) != 0 || LSB(ctx->remote_ip6[2], 3) != 0 ||
+		    LSB(ctx->remote_ip6[3], 0) != 0 || LSB(ctx->remote_ip6[3], 1) != 0 ||
+		    LSB(ctx->remote_ip6[3], 2) != 0 || LSB(ctx->remote_ip6[3], 3) != 0)
+			return SK_DROP;
+		if (LSW(ctx->remote_ip6[0], 0) != 0 || LSW(ctx->remote_ip6[0], 1) != 0 ||
+		    LSW(ctx->remote_ip6[1], 0) != 0 || LSW(ctx->remote_ip6[1], 1) != 0 ||
+		    LSW(ctx->remote_ip6[2], 0) != 0 || LSW(ctx->remote_ip6[2], 1) != 0 ||
+		    LSW(ctx->remote_ip6[3], 0) != 0 || LSW(ctx->remote_ip6[3], 1) != 0)
+			return SK_DROP;
+
+		if (LSB(ctx->local_ip6[0], 0) != 0 || LSB(ctx->local_ip6[0], 1) != 0 ||
+		    LSB(ctx->local_ip6[0], 2) != 0 || LSB(ctx->local_ip6[0], 3) != 0 ||
+		    LSB(ctx->local_ip6[1], 0) != 0 || LSB(ctx->local_ip6[1], 1) != 0 ||
+		    LSB(ctx->local_ip6[1], 2) != 0 || LSB(ctx->local_ip6[1], 3) != 0 ||
+		    LSB(ctx->local_ip6[2], 0) != 0 || LSB(ctx->local_ip6[2], 1) != 0 ||
+		    LSB(ctx->local_ip6[2], 2) != 0 || LSB(ctx->local_ip6[2], 3) != 0 ||
+		    LSB(ctx->local_ip6[3], 0) != 0 || LSB(ctx->local_ip6[3], 1) != 0 ||
+		    LSB(ctx->local_ip6[3], 2) != 0 || LSB(ctx->local_ip6[3], 3) != 0)
+			return SK_DROP;
+		if (LSW(ctx->remote_ip6[0], 0) != 0 || LSW(ctx->remote_ip6[0], 1) != 0 ||
+		    LSW(ctx->remote_ip6[1], 0) != 0 || LSW(ctx->remote_ip6[1], 1) != 0 ||
+		    LSW(ctx->remote_ip6[2], 0) != 0 || LSW(ctx->remote_ip6[2], 1) != 0 ||
+		    LSW(ctx->remote_ip6[3], 0) != 0 || LSW(ctx->remote_ip6[3], 1) != 0)
+			return SK_DROP;
+	}
+
+	/* Success, redirect to KEY_SERVER_B */
+	sk = bpf_map_lookup_elem(&redir_map, &KEY_SERVER_B);
+	if (sk) {
+		bpf_sk_assign(ctx, sk, 0);
+		bpf_sk_release(sk);
+	}
+	return SK_PASS;
+}
+
+/* Check that sk_assign rejects SERVER_A socket with -ESOCKNOSUPPORT */
+SEC("sk_lookup")
+int sk_assign_esocknosupport(struct bpf_sk_lookup *ctx)
+{
+	struct bpf_sock *sk;
+	int err, ret;
+
+	ret = SK_DROP;
+	sk = bpf_map_lookup_elem(&redir_map, &KEY_SERVER_A);
+	if (!sk)
+		goto out;
+
+	err = bpf_sk_assign(ctx, sk, 0);
+	if (err != -ESOCKTNOSUPPORT) {
+		bpf_printk("sk_assign returned %d, expected %d\n",
+			   err, -ESOCKTNOSUPPORT);
+		goto out;
+	}
+
+	ret = SK_PASS; /* Success, pass to regular lookup */
+out:
+	if (sk)
+		bpf_sk_release(sk);
+	return ret;
+}
+
+SEC("sk_lookup")
+int multi_prog_pass1(struct bpf_sk_lookup *ctx)
+{
+	bpf_map_update_elem(&run_map, &KEY_PROG1, &PROG_DONE, BPF_ANY);
+	return SK_PASS;
+}
+
+SEC("sk_lookup")
+int multi_prog_pass2(struct bpf_sk_lookup *ctx)
+{
+	bpf_map_update_elem(&run_map, &KEY_PROG2, &PROG_DONE, BPF_ANY);
+	return SK_PASS;
+}
+
+SEC("sk_lookup")
+int multi_prog_drop1(struct bpf_sk_lookup *ctx)
+{
+	bpf_map_update_elem(&run_map, &KEY_PROG1, &PROG_DONE, BPF_ANY);
+	return SK_DROP;
+}
+
+SEC("sk_lookup")
+int multi_prog_drop2(struct bpf_sk_lookup *ctx)
+{
+	bpf_map_update_elem(&run_map, &KEY_PROG2, &PROG_DONE, BPF_ANY);
+	return SK_DROP;
+}
+
+static __always_inline int select_server_a(struct bpf_sk_lookup *ctx)
+{
+	struct bpf_sock *sk;
+	int err;
+
+	sk = bpf_map_lookup_elem(&redir_map, &KEY_SERVER_A);
+	if (!sk)
+		return SK_DROP;
+
+	err = bpf_sk_assign(ctx, sk, 0);
+	bpf_sk_release(sk);
+	if (err)
+		return SK_DROP;
+
+	return SK_PASS;
+}
+
+SEC("sk_lookup")
+int multi_prog_redir1(struct bpf_sk_lookup *ctx)
+{
+	int ret;
+
+	ret = select_server_a(ctx);
+	bpf_map_update_elem(&run_map, &KEY_PROG1, &PROG_DONE, BPF_ANY);
+	return SK_PASS;
+}
+
+SEC("sk_lookup")
+int multi_prog_redir2(struct bpf_sk_lookup *ctx)
+{
+	int ret;
+
+	ret = select_server_a(ctx);
+	bpf_map_update_elem(&run_map, &KEY_PROG2, &PROG_DONE, BPF_ANY);
+	return SK_PASS;
+}
+
+char _license[] SEC("license") = "Dual BSD/GPL";