Test redirection logic. All supported and unsupported redirect combinations
are tested for success and failure respectively.
BPF_MAP_TYPE_SOCKMAP
BPF_MAP_TYPE_SOCKHASH
x
sk_msg-to-egress
sk_msg-to-ingress
sk_skb-to-egress
sk_skb-to-ingress
x
AF_INET, SOCK_STREAM
AF_INET6, SOCK_STREAM
AF_INET, SOCK_DGRAM
AF_INET6, SOCK_DGRAM
AF_UNIX, SOCK_STREAM
AF_UNIX, SOCK_DGRAM
AF_VSOCK, SOCK_STREAM
AF_VSOCK, SOCK_SEQPACKET
Suggested-by: Jakub Sitnicki <ja...@cloudflare.com>
Signed-off-by: Michal Luczaj <m...@rbox.co>
---
.../selftests/bpf/prog_tests/sockmap_redir.c | 461 +++++++++++++++++++++
1 file changed, 461 insertions(+)
diff --git a/tools/testing/selftests/bpf/prog_tests/sockmap_redir.c
b/tools/testing/selftests/bpf/prog_tests/sockmap_redir.c
new file mode 100644
index
0000000000000000000000000000000000000000..df550759c7e50d248322be3655b02b3a21267b4a
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/sockmap_redir.c
@@ -0,0 +1,461 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Test for sockmap/sockhash redirection.
+ *
+ * BPF_MAP_TYPE_SOCKMAP
+ * BPF_MAP_TYPE_SOCKHASH
+ * x
+ * sk_msg-to-egress
+ * sk_msg-to-ingress
+ * sk_skb-to-egress
+ * sk_skb-to-ingress
+ * x
+ * AF_INET, SOCK_STREAM
+ * AF_INET6, SOCK_STREAM
+ * AF_INET, SOCK_DGRAM
+ * AF_INET6, SOCK_DGRAM
+ * AF_UNIX, SOCK_STREAM
+ * AF_UNIX, SOCK_DGRAM
+ * AF_VSOCK, SOCK_STREAM
+ * AF_VSOCK, SOCK_SEQPACKET
+ */
+
+#include <errno.h>
+#include <error.h>
+#include <sched.h>
+#include <stdio.h>
+#include <unistd.h>
+
+#include <netinet/in.h>
+#include <sys/socket.h>
+#include <sys/types.h>
+#include <sys/un.h>
+#include <linux/string.h>
+#include <linux/vm_sockets.h>
+
+#include <bpf/bpf.h>
+#include <bpf/libbpf.h>
+
+#include "linux/const.h"
+#include "test_progs.h"
+#include "sockmap_helpers.h"
+#include "test_sockmap_listen.skel.h"
+
+/* The meaning of SUPPORTED is "will redirect packet as expected".
+ */
+#define SUPPORTED _BITUL(0)
+
+/* Note on sk_skb-to-ingress ->af_vsock:
+ *
+ * Peer socket may receive the packet some time after the return from
sendmsg().
+ * In a typical usage scenario, recvmsg() will block until the redirected
packet
+ * appears in the destination queue, or timeout if the packet was dropped. By
+ * that point, the verdict map has already been updated to reflect what has
+ * happened.
+ *
+ * But sk_skb-to-ingress/af_vsock is an unsupported combination, so no
recvmsg()
+ * takes place. Which means we may race the execution of the verdict logic and
+ * read map_verd before it has been updated, i.e. we might observe
+ * map_verd[SK_DROP]=0 instead of map_verd[SK_DROP]=1.
+ *
+ * This confuses the selftest logic: if there was no packet dropped, where's
the
+ * packet? So here's a heuristic: on map_verd[SK_DROP]=map_verd[SK_PASS]=0
+ * (which implies the verdict program has not been ran) just re-read the
verdict
+ * map again.
+ */
+#define UNSUPPORTED_RACY_VERD _BITUL(1)
+
+enum prog_type {
+ SK_MSG_EGRESS,
+ SK_MSG_INGRESS,
+ SK_SKB_EGRESS,
+ SK_SKB_INGRESS,
+};
+
+enum {
+ SEND_INNER = 0,
+ SEND_OUTER,
+};
+
+enum {
+ RECV_INNER = 0,
+ RECV_OUTER,
+};
+
+struct maps {
+ int in;
+ int out;
+ int verd;
+};
+
+struct combo_spec {
+ enum prog_type prog_type;
+ const char *in, *out;
+};
+
+struct redir_spec {
+ const char *name;
+ int idx_send;
+ int idx_recv;
+ enum prog_type prog_type;
+};
+
+struct socket_spec {
+ int family;
+ int sotype;
+ int send_flags;
+ int in[2];
+ int out[2];
+};
+
+static int socket_spec_pairs(struct socket_spec *s)
+{
+ return create_socket_pairs(s->family, s->sotype,
+ &s->in[0], &s->out[0],
+ &s->in[1], &s->out[1]);
+}
+
+static void socket_spec_close(struct socket_spec *s)
+{
+ xclose(s->in[0]);
+ xclose(s->in[1]);
+ xclose(s->out[0]);
+ xclose(s->out[1]);
+}
+
+static void get_redir_params(struct redir_spec *redir,
+ struct test_sockmap_listen *skel,
+ int *prog_fd, enum bpf_attach_type *attach_type,
+ bool *ingress_flag)
+{
+ enum prog_type type = redir->prog_type;
+ struct bpf_program *prog;
+ bool sk_msg;
+
+ sk_msg = type == SK_MSG_INGRESS || type == SK_MSG_EGRESS;
+ prog = sk_msg ? skel->progs.prog_msg_verdict :
skel->progs.prog_skb_verdict;
+
+ *prog_fd = bpf_program__fd(prog);
+ *attach_type = sk_msg ? BPF_SK_MSG_VERDICT : BPF_SK_SKB_VERDICT;
+ *ingress_flag = type == SK_MSG_INGRESS || type == SK_SKB_INGRESS;
+}
+
+static void try_recv(const char *prefix, int fd, int flags, bool
expect_success)
+{
+ ssize_t n;
+ char buf;
+
+ errno = 0;
+ n = recv(fd, &buf, 1, flags);
+ if (n < 0 && expect_success)
+ FAIL_ERRNO("%s: unexpected failure: retval=%zd", prefix, n);
+ if (!n && !expect_success)
+ FAIL("%s: expected failure: retval=%zd", prefix, n);
+}
+
+static void handle_unsupported(int sd_send, int sd_peer, int sd_in, int sd_out,
+ int sd_recv, int map_verd, int status)
+{
+ unsigned int drop, pass;
+ char recv_buf;
+ ssize_t n;
+
+get_verdict:
+ if (xbpf_map_lookup_elem(map_verd, &u32(SK_DROP), &drop) ||
+ xbpf_map_lookup_elem(map_verd, &u32(SK_PASS), &pass))
+ return;
+
+ if (pass == 0 && drop == 0 && (status & UNSUPPORTED_RACY_VERD)) {
+ sched_yield();
+ goto get_verdict;
+ }
+
+ if (pass != 0) {
+ FAIL("unsupported: wanted verdict pass 0, have %u", pass);
+ return;
+ }
+
+ /* If nothing was dropped, packet should have reached the peer */
+ if (drop == 0) {
+ errno = 0;
+ n = recv_timeout(sd_peer, &recv_buf, 1, 0, IO_TIMEOUT_SEC);
+ if (n != 1)
+ FAIL_ERRNO("unsupported: packet missing, retval=%zd",
n);
+ }
+
+ /* Ensure queues are empty */
+ try_recv("bpf.recv(sd_send)", sd_send, MSG_DONTWAIT, false);
+ if (sd_in != sd_send)
+ try_recv("bpf.recv(sd_in)", sd_in, MSG_DONTWAIT, false);
+
+ try_recv("bpf.recv(sd_out)", sd_out, MSG_DONTWAIT, false);
+ if (sd_recv != sd_out)
+ try_recv("bpf.recv(sd_recv)", sd_recv, MSG_DONTWAIT, false);
+}
+
+static void test_send_redir_recv(int sd_send, int send_flags, int sd_peer,
+ int sd_in, int sd_out, int sd_recv,
+ struct maps *maps, int status)
+{
+ unsigned int drop, pass;
+ char *send_buf = "ab";
+ char recv_buf = '\0';
+ ssize_t n, len = 1;
+
+ /* Zero out the verdict map */
+ if (xbpf_map_update_elem(maps->verd, &u32(SK_DROP), &u32(0), BPF_ANY) ||
+ xbpf_map_update_elem(maps->verd, &u32(SK_PASS), &u32(0), BPF_ANY))
+ return;
+
+ if (xbpf_map_update_elem(maps->in, &u32(0), &u64(sd_in), BPF_NOEXIST))
+ return;
+
+ if (xbpf_map_update_elem(maps->out, &u32(0), &u64(sd_out), BPF_NOEXIST))
+ goto del_in;
+
+ /* Last byte is OOB data when send_flags has MSG_OOB bit set */
+ if (send_flags & MSG_OOB)
+ len++;
+ n = send(sd_send, send_buf, len, send_flags);
+ if (n >= 0 && n < len)
+ FAIL("incomplete send");
+ if (n < 0) {
+ /* sk_msg redirect combo not supported? */
+ if (status & SUPPORTED || errno != EACCES)
+ FAIL_ERRNO("send");
+ goto out;
+ }
+
+ if (!(status & SUPPORTED)) {
+ handle_unsupported(sd_send, sd_peer, sd_in, sd_out, sd_recv,
+ maps->verd, status);
+ goto out;
+ }
+
+ errno = 0;
+ n = recv_timeout(sd_recv, &recv_buf, 1, 0, IO_TIMEOUT_SEC);
+ if (n != 1) {
+ FAIL_ERRNO("recv_timeout()");
+ goto out;
+ }
+
+ /* Check verdict _after_ recv(); af_vsock may need time to catch up */
+ if (xbpf_map_lookup_elem(maps->verd, &u32(SK_DROP), &drop) ||
+ xbpf_map_lookup_elem(maps->verd, &u32(SK_PASS), &pass))
+ goto out;
+
+ if (drop != 0 || pass != 1)
+ FAIL("unexpected verdict drop/pass: wanted 0/1, have %u/%u",
+ drop, pass);
+
+ if (recv_buf != send_buf[0])
+ FAIL("recv(): payload check, %02x != %02x", recv_buf,
send_buf[0]);
+
+ if (send_flags & MSG_OOB) {
+ /* Fail reading OOB while in sockmap */
+ try_recv("bpf.recv(sd_out, MSG_OOB)", sd_out,
+ MSG_OOB | MSG_DONTWAIT, false);
+
+ /* Remove sd_out from sockmap */
+ xbpf_map_delete_elem(maps->out, &u32(0));
+
+ /* Check that OOB was dropped on redirect */
+ try_recv("recv(sd_out, MSG_OOB)", sd_out,
+ MSG_OOB | MSG_DONTWAIT, false);
+
+ goto del_in;
+ }
+out:
+ xbpf_map_delete_elem(maps->out, &u32(0));
+del_in:
+ xbpf_map_delete_elem(maps->in, &u32(0));
+}
+
+static int is_redir_supported(enum prog_type type, const char *in,
+ const char *out)
+{
+ /* Matching based on strings returned by socket_kind_to_str():
+ * tcp4, udp4, tcp6, udp6, u_str, u_dgr, v_str, v_seq
+ * Plus a wildcard: any
+ * Not in use: u_seq, v_dgr
+ */
+ struct combo_spec *c, combos[] = {
+ /* Send to local: TCP -> any, but vsock */
+ { SK_MSG_INGRESS, "tcp", "tcp" },
+ { SK_MSG_INGRESS, "tcp", "udp" },
+ { SK_MSG_INGRESS, "tcp", "u_str" },
+ { SK_MSG_INGRESS, "tcp", "u_dgr" },
+
+ /* Send to egress: TCP -> TCP */
+ { SK_MSG_EGRESS, "tcp", "tcp" },
+
+ /* Ingress to egress: any -> any */
+ { SK_SKB_EGRESS, "any", "any" },
+
+ /* Ingress to local: any -> any, but vsock */
+ { SK_SKB_INGRESS, "any", "tcp" },
+ { SK_SKB_INGRESS, "any", "udp" },
+ { SK_SKB_INGRESS, "any", "u_str" },
+ { SK_SKB_INGRESS, "any", "u_dgr" },
+ };
+
+ for (c = combos; c < combos + ARRAY_SIZE(combos); c++) {
+ if (c->prog_type == type &&
+ (!strcmp(c->in, "any") || strstarts(in, c->in)) &&
+ (!strcmp(c->out, "any") || strstarts(out, c->out)))
+ return SUPPORTED;
+ }
+
+ return 0;
+}
+
+static int get_support_status(enum prog_type type, const char *in,
+ const char *out)
+{
+ int status = is_redir_supported(type, in, out);
+
+ if (type == SK_SKB_INGRESS && strstarts(out, "v_"))
+ status |= UNSUPPORTED_RACY_VERD;
+
+ return status;
+}
+
+static void test_socket(enum bpf_map_type type, struct redir_spec *redir,
+ struct maps *maps, struct socket_spec *s_in,
+ struct socket_spec *s_out)
+{
+ int fd_in, fd_out, fd_send, fd_peer, fd_recv, flags, status;
+ const char *in_str, *out_str;
+ char s[MAX_TEST_NAME];
+
+ fd_in = s_in->in[0];
+ fd_out = s_out->out[0];
+ fd_send = s_in->in[redir->idx_send];
+ fd_peer = s_in->in[redir->idx_send ^ 1];
+ fd_recv = s_out->out[redir->idx_recv];
+ flags = s_in->send_flags;
+
+ in_str = socket_kind_to_str(fd_in);
+ out_str = socket_kind_to_str(fd_out);
+ status = get_support_status(redir->prog_type, in_str, out_str);
+
+ snprintf(s, sizeof(s),
+ "%-4s %-17s %-5s %s %-5s%6s",
+ /* hash sk_skb-to-ingress u_str → v_str (OOB) */
+ type == BPF_MAP_TYPE_SOCKMAP ? "map" : "hash",
+ redir->name,
+ in_str,
+ status & SUPPORTED ? "→" : " ",
+ out_str,
+ (flags & MSG_OOB) ? "(OOB)" : "");
+
+ if (!test__start_subtest(s))
+ return;
+
+ test_send_redir_recv(fd_send, flags, fd_peer, fd_in, fd_out, fd_recv,
+ maps, status);
+}
+
+static void test_redir(enum bpf_map_type type, struct redir_spec *redir,
+ struct maps *maps)
+{
+ struct socket_spec *s, sockets[] = {
+ { AF_INET, SOCK_STREAM },
+ // { AF_INET, SOCK_STREAM, MSG_OOB }, /* Known to be broken */
+ { AF_INET6, SOCK_STREAM },
+ { AF_INET, SOCK_DGRAM },
+ { AF_INET6, SOCK_DGRAM },
+ { AF_UNIX, SOCK_STREAM },
+ { AF_UNIX, SOCK_STREAM, MSG_OOB },
+ { AF_UNIX, SOCK_DGRAM },
+ // { AF_UNIX, SOCK_SEQPACKET}, /* Unsupported
BPF_MAP_UPDATE_ELEM */
+ { AF_VSOCK, SOCK_STREAM },
+ // { AF_VSOCK, SOCK_DGRAM }, /* Unsupported socket() */
+ { AF_VSOCK, SOCK_SEQPACKET },
+ };
+
+ for (s = sockets; s < sockets + ARRAY_SIZE(sockets); s++)
+ if (socket_spec_pairs(s))
+ goto out;
+
+ /* Intra-proto */
+ for (s = sockets; s < sockets + ARRAY_SIZE(sockets); s++)
+ test_socket(type, redir, maps, s, s);
+
+ /* Cross-proto */
+ for (int i = 0; i < ARRAY_SIZE(sockets); i++) {
+ for (int j = 0; j < ARRAY_SIZE(sockets); j++) {
+ struct socket_spec *out = &sockets[j];
+ struct socket_spec *in = &sockets[i];
+
+ /* Skip intra-proto and between variants */
+ if (out->send_flags ||
+ (in->family == out->family &&
+ in->sotype == out->sotype))
+ continue;
+
+ test_socket(type, redir, maps, in, out);
+ }
+ }
+out:
+ while (--s >= sockets)
+ socket_spec_close(s);
+}
+
+static void test_map(enum bpf_map_type type)
+{
+ struct redir_spec *r, redirs[] = {
+ { "sk_msg-to-ingress", SEND_INNER, RECV_INNER, SK_MSG_INGRESS },
+ { "sk_msg-to-egress", SEND_INNER, RECV_OUTER, SK_MSG_EGRESS },
+ { "sk_skb-to-egress", SEND_OUTER, RECV_OUTER, SK_SKB_EGRESS },
+ { "sk_skb-to-ingress", SEND_OUTER, RECV_INNER, SK_SKB_INGRESS },
+ };
+
+ for (r = redirs; r < redirs + ARRAY_SIZE(redirs); r++) {
+ enum bpf_attach_type attach_type;
+ struct test_sockmap_listen *skel;
+ struct maps maps;
+ int prog_fd;
+
+ skel = test_sockmap_listen__open_and_load();
+ if (!skel) {
+ FAIL("open_and_load");
+ return;
+ }
+
+ switch (type) {
+ case BPF_MAP_TYPE_SOCKMAP:
+ skel->bss->test_sockmap = true;
+ maps.out = bpf_map__fd(skel->maps.sock_map);
+ break;
+ case BPF_MAP_TYPE_SOCKHASH:
+ skel->bss->test_sockmap = false;
+ maps.out = bpf_map__fd(skel->maps.sock_hash);
+ break;
+ default:
+ FAIL("Unsupported bpf_map_type");
+ return;
+ }
+
+ maps.in = bpf_map__fd(skel->maps.nop_map);
+ maps.verd = bpf_map__fd(skel->maps.verdict_map);
+ get_redir_params(r, skel, &prog_fd, &attach_type,
+ &skel->bss->test_ingress);
+
+ if (xbpf_prog_attach(prog_fd, maps.in, attach_type, 0))
+ return;
+
+ test_redir(type, r, &maps);
+
+ if (xbpf_prog_detach2(prog_fd, maps.in, attach_type))
+ return;
+
+ test_sockmap_listen__destroy(skel);
+ }
+}
+
+void serial_test_sockmap_redir(void)
+{
+ test_map(BPF_MAP_TYPE_SOCKMAP);
+ test_map(BPF_MAP_TYPE_SOCKHASH);
+}
--
2.49.0
