diff mbox series

[bpf-next,v4,4/4] selftests/bpf: Add a selftest for the tracing bpf_get_socket_cookie

Message ID 20201209132636.1545761-4-revest@chromium.org (mailing list archive)
State Changes Requested
Delegated to: BPF
Headers show
Series [bpf-next,v4,1/4] bpf: Be less specific about socket cookies guarantees | expand

Checks

Context Check Description
netdev/cover_letter warning Series does not have a cover letter
netdev/fixes_present success Link
netdev/patch_count success Link
netdev/tree_selection success Clearly marked for bpf-next
netdev/subject_prefix success Link
netdev/source_inline success Was 0 now: 0
netdev/verify_signedoff success Link
netdev/module_param success Was 0 now: 0
netdev/build_32bit success Errors and warnings before: 0 this patch: 0
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/verify_fixes success Link
netdev/checkpatch warning CHECK: Lines should not end with a '('
netdev/build_allmodconfig_warn success Errors and warnings before: 0 this patch: 0
netdev/header_inline success Link
netdev/stable success Stable not CCed

Commit Message

Florent Revest Dec. 9, 2020, 1:26 p.m. UTC
This builds up on the existing socket cookie test which checks whether
the bpf_get_socket_cookie helpers provide the same value in
cgroup/connect6 and sockops programs for a socket created by the
userspace part of the test.

Adding a tracing program to the existing objects requires a different
attachment strategy and different headers.

Signed-off-by: Florent Revest <revest@chromium.org>
---
 .../selftests/bpf/prog_tests/socket_cookie.c  | 24 +++++++----
 .../selftests/bpf/progs/socket_cookie_prog.c  | 41 ++++++++++++++++---
 2 files changed, 52 insertions(+), 13 deletions(-)
diff mbox series

Patch

diff --git a/tools/testing/selftests/bpf/prog_tests/socket_cookie.c b/tools/testing/selftests/bpf/prog_tests/socket_cookie.c
index 53d0c44e7907..e5c5e2ea1deb 100644
--- a/tools/testing/selftests/bpf/prog_tests/socket_cookie.c
+++ b/tools/testing/selftests/bpf/prog_tests/socket_cookie.c
@@ -15,8 +15,8 @@  struct socket_cookie {
 
 void test_socket_cookie(void)
 {
+	struct bpf_link *set_link, *update_sockops_link, *update_tracing_link;
 	socklen_t addr_len = sizeof(struct sockaddr_in6);
-	struct bpf_link *set_link, *update_link;
 	int server_fd, client_fd, cgroup_fd;
 	struct socket_cookie_prog *skel;
 	__u32 cookie_expected_value;
@@ -39,15 +39,21 @@  void test_socket_cookie(void)
 		  PTR_ERR(set_link)))
 		goto close_cgroup_fd;
 
-	update_link = bpf_program__attach_cgroup(skel->progs.update_cookie,
-						 cgroup_fd);
-	if (CHECK(IS_ERR(update_link), "update-link-cg-attach", "err %ld\n",
-		  PTR_ERR(update_link)))
+	update_sockops_link = bpf_program__attach_cgroup(
+		skel->progs.update_cookie_sockops, cgroup_fd);
+	if (CHECK(IS_ERR(update_sockops_link), "update-sockops-link-cg-attach",
+		  "err %ld\n", PTR_ERR(update_sockops_link)))
 		goto free_set_link;
 
+	update_tracing_link = bpf_program__attach(
+		skel->progs.update_cookie_tracing);
+	if (CHECK(IS_ERR(update_tracing_link), "update-tracing-link-attach",
+		  "err %ld\n", PTR_ERR(update_tracing_link)))
+		goto free_update_sockops_link;
+
 	server_fd = start_server(AF_INET6, SOCK_STREAM, "::1", 0, 0);
 	if (CHECK(server_fd < 0, "start_server", "errno %d\n", errno))
-		goto free_update_link;
+		goto free_update_tracing_link;
 
 	client_fd = connect_to_fd(server_fd, 0);
 	if (CHECK(client_fd < 0, "connect_to_fd", "errno %d\n", errno))
@@ -71,8 +77,10 @@  void test_socket_cookie(void)
 	close(client_fd);
 close_server_fd:
 	close(server_fd);
-free_update_link:
-	bpf_link__destroy(update_link);
+free_update_tracing_link:
+	bpf_link__destroy(update_tracing_link);
+free_update_sockops_link:
+	bpf_link__destroy(update_sockops_link);
 free_set_link:
 	bpf_link__destroy(set_link);
 close_cgroup_fd:
diff --git a/tools/testing/selftests/bpf/progs/socket_cookie_prog.c b/tools/testing/selftests/bpf/progs/socket_cookie_prog.c
index 81e84be6f86d..1f770b732cb1 100644
--- a/tools/testing/selftests/bpf/progs/socket_cookie_prog.c
+++ b/tools/testing/selftests/bpf/progs/socket_cookie_prog.c
@@ -1,11 +1,13 @@ 
 // SPDX-License-Identifier: GPL-2.0
 // Copyright (c) 2018 Facebook
 
-#include <linux/bpf.h>
-#include <sys/socket.h>
+#include "vmlinux.h"
 
 #include <bpf/bpf_helpers.h>
 #include <bpf/bpf_endian.h>
+#include <bpf/bpf_tracing.h>
+
+#define AF_INET6 10
 
 struct socket_cookie {
 	__u64 cookie_key;
@@ -19,6 +21,14 @@  struct {
 	__type(value, struct socket_cookie);
 } socket_cookies SEC(".maps");
 
+/*
+ * These three programs get executed in a row on connect() syscalls. The
+ * userspace side of the test creates a client socket, issues a connect() on it
+ * and then checks that the local storage associated with this socket has:
+ * cookie_value == local_port << 8 | 0xFF
+ * The different parts of this cookie_value are appended by those hooks if they
+ * all agree on the output of bpf_get_socket_cookie().
+ */
 SEC("cgroup/connect6")
 int set_cookie(struct bpf_sock_addr *ctx)
 {
@@ -32,14 +42,14 @@  int set_cookie(struct bpf_sock_addr *ctx)
 	if (!p)
 		return 1;
 
-	p->cookie_value = 0xFF;
+	p->cookie_value = 0xF;
 	p->cookie_key = bpf_get_socket_cookie(ctx);
 
 	return 1;
 }
 
 SEC("sockops")
-int update_cookie(struct bpf_sock_ops *ctx)
+int update_cookie_sockops(struct bpf_sock_ops *ctx)
 {
 	struct bpf_sock *sk;
 	struct socket_cookie *p;
@@ -60,9 +70,30 @@  int update_cookie(struct bpf_sock_ops *ctx)
 	if (p->cookie_key != bpf_get_socket_cookie(ctx))
 		return 1;
 
-	p->cookie_value = (ctx->local_port << 8) | p->cookie_value;
+	p->cookie_value |= (ctx->local_port << 8);
 
 	return 1;
 }
 
+SEC("fexit/inet_stream_connect")
+int BPF_PROG(update_cookie_tracing, struct socket *sock,
+	     struct sockaddr *uaddr, int addr_len, int flags)
+{
+	struct socket_cookie *p;
+
+	if (uaddr->sa_family != AF_INET6)
+		return 0;
+
+	p = bpf_sk_storage_get(&socket_cookies, sock->sk, 0, 0);
+	if (!p)
+		return 0;
+
+	if (p->cookie_key != bpf_get_socket_cookie(sock->sk))
+		return 0;
+
+	p->cookie_value |= 0xF0;
+
+	return 0;
+}
+
 char _license[] SEC("license") = "GPL";