[PATCH v2 net-next 3/3] selftests/bpf: Add test for SO_BINDTODEVICE opt of bpf_setsockopt

Ferenc Fejes
2020-05-30T21:10:08Z

This test intended to verify if SO_BINDTODEVICE option works in
bpf_setsockopt. Because we already in the SOL_SOCKET level in this
connect bpf prog its safe to verify the sanity in the beginning of
the connect_v4_prog by calling the bind_to_device test helper.

The testing environment already created by the test_sock_addr.sh
script so this test assume that two netdevices already existing in
the system: veth pair with names test_sock_addr1 and test_sock_addr2.
The test will try to bind the socket to those devices first.
Then the test assume there are no netdevice with "nonexistent_dev"
name so the bpf_setsockopt will give use ENODEV error.
At the end the test remove the device binding from the socket
by binding it to an empty name.

Signed-off-by: Ferenc Fejes <fejes@inf.elte.hu>
---
.../selftests/bpf/progs/connect4_prog.c | 33 +++++++++++++++++++
1 file changed, 33 insertions(+)

diff --git a/tools/testing/selftests/bpf/progs/connect4_prog.c b/tools/testing/selftests/bpf/progs/connect4_prog.c
index c2c85c31cffd..1ab2c5eba86c 100644
--- a/tools/testing/selftests/bpf/progs/connect4_prog.c
+++ b/tools/testing/selftests/bpf/progs/connect4_prog.c
@@ -9,6 +9,8 @@
#include <linux/in6.h>
#include <sys/socket.h>
#include <netinet/tcp.h>
+#include <linux/if.h>
+#include <errno.h>

#include <bpf/bpf_helpers.h>
#include <bpf/bpf_endian.h>
@@ -21,6 +23,10 @@
#define TCP_CA_NAME_MAX 16
#endif

+#ifndef IFNAMSIZ
+#define IFNAMSIZ 16
+#endif
+
int _version SEC("version") = 1;

__attribute__ ((noinline))
@@ -75,6 +81,29 @@ static __inline int set_cc(struct bpf_sock_addr *ctx)
return 0;
}

+static __inline int bind_to_device(struct bpf_sock_addr *ctx)
+{
+ char veth1[IFNAMSIZ] = "test_sock_addr1";
+ char veth2[IFNAMSIZ] = "test_sock_addr2";
+ char missing[IFNAMSIZ] = "nonexistent_dev";
+ char del_bind[IFNAMSIZ] = "";
+
+ if (bpf_setsockopt(ctx, SOL_SOCKET, SO_BINDTODEVICE,
+ &veth1, sizeof(veth1)))
+ return 1;
+ if (bpf_setsockopt(ctx, SOL_SOCKET, SO_BINDTODEVICE,
+ &veth2, sizeof(veth2)))
+ return 1;
+ if (bpf_setsockopt(ctx, SOL_SOCKET, SO_BINDTODEVICE,
+ &missing, sizeof(missing)) != -ENODEV)
+ return 1;
+ if (bpf_setsockopt(ctx, SOL_SOCKET, SO_BINDTODEVICE,
+ &del_bind, sizeof(del_bind)))
+ return 1;
+
+ return 0;
+}
+
SEC("cgroup/connect4")
int connect_v4_prog(struct bpf_sock_addr *ctx)
{
@@ -88,6 +117,10 @@ int connect_v4_prog(struct bpf_sock_addr *ctx)
tuple.ipv4.daddr = bpf_htonl(DST_REWRITE_IP4);
tuple.ipv4.dport = bpf_htons(DST_REWRITE_PORT4);

+ /* Bind to device and unbind it. */
+ if (bind_to_device(ctx))
+ return 0;
+
if (ctx->type != SOCK_STREAM && ctx->type != SOCK_DGRAM)
return 0;
else if (ctx->type == SOCK_STREAM)
--
2.17.1