Commit ccc090f4 authored by Geliang Tang's avatar Geliang Tang Committed by Andrii Nakryiko
Browse files

selftests/bpf: Verify ca_name of struct mptcp_sock 



This patch verifies another member of struct mptcp_sock, ca_name. Add a
new function get_msk_ca_name() to read the sysctl tcp_congestion_control
and verify it in verify_msk().

v3: Access the sysctl through the filesystem to avoid compatibility
    issues with the busybox sysctl command.

v4: use ASSERT_* instead of CHECK_FAIL (Andrii)

v5: use ASSERT_STRNEQ() instead of strncmp() (Andrii)

Signed-off-by: default avatarGeliang Tang <geliang.tang@suse.com>
Signed-off-by: default avatarMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: default avatarAndrii Nakryiko <andrii@kernel.org>
Acked-by: default avatarMatthieu Baerts <matthieu.baerts@tessares.net>
Link: https://lore.kernel.org/bpf/20220519233016.105670-7-mathew.j.martineau@linux.intel.com
parent 02662234

tools/testing/selftests/bpf/bpf_tcp_helpers.h

+5 −0
Original line number Diff line number Diff line
@@ -16,6 +16,10 @@ BPF_PROG(name, args) 
#define SOL_TCP 6

#endif



#ifndef TCP_CA_NAME_MAX

#define TCP_CA_NAME_MAX	16

#endif



#define tcp_jiffies32 ((__u32)bpf_jiffies64())



struct sock_common {
@@ -230,6 +234,7 @@ struct mptcp_sock { 
	struct inet_connection_sock	sk;



	__u32		token;

	char		ca_name[TCP_CA_NAME_MAX];

} __attribute__((preserve_access_index));



#endif

tools/testing/selftests/bpf/prog_tests/mptcp.c

+31 −0
Original line number Diff line number Diff line
@@ -7,10 +7,15 @@ 
#include "network_helpers.h"

#include "mptcp_sock.skel.h"



#ifndef TCP_CA_NAME_MAX

#define TCP_CA_NAME_MAX	16

#endif



struct mptcp_storage {

	__u32 invoked;

	__u32 is_mptcp;

	__u32 token;

	char ca_name[TCP_CA_NAME_MAX];

};



static int verify_tsk(int map_fd, int client_fd)
@@ -31,14 +36,37 @@ static int verify_tsk(int map_fd, int client_fd) 
	return err;

}



static void get_msk_ca_name(char ca_name[])

{

	size_t len;

	int fd;



	fd = open("/proc/sys/net/ipv4/tcp_congestion_control", O_RDONLY);

	if (!ASSERT_GE(fd, 0, "failed to open tcp_congestion_control"))

		return;



	len = read(fd, ca_name, TCP_CA_NAME_MAX);

	if (!ASSERT_GT(len, 0, "failed to read ca_name"))

		goto err;



	if (len > 0 && ca_name[len - 1] == '\n')

		ca_name[len - 1] = '\0';



err:

	close(fd);

}



static int verify_msk(int map_fd, int client_fd, __u32 token)

{

	char ca_name[TCP_CA_NAME_MAX];

	int err, cfd = client_fd;

	struct mptcp_storage val;



	if (!ASSERT_GT(token, 0, "invalid token"))

		return -1;



	get_msk_ca_name(ca_name);



	err = bpf_map_lookup_elem(map_fd, &cfd, &val);

	if (!ASSERT_OK(err, "bpf_map_lookup_elem"))

		return err;
@@ -52,6 +80,9 @@ static int verify_msk(int map_fd, int client_fd, __u32 token) 
	if (!ASSERT_EQ(val.token, token, "unexpected token"))

		err++;



	if (!ASSERT_STRNEQ(val.ca_name, ca_name, TCP_CA_NAME_MAX, "unexpected ca_name"))

		err++;



	return err;

}

tools/testing/selftests/bpf/progs/mptcp_sock.c

+3 −0
Original line number Diff line number Diff line
@@ -13,6 +13,7 @@ struct mptcp_storage { 
	__u32 invoked;

	__u32 is_mptcp;

	__u32 token;

	char ca_name[TCP_CA_NAME_MAX];

};



struct {
@@ -51,6 +52,7 @@ int _sockops(struct bpf_sock_ops *ctx) 
			return 1;



		storage->token = 0;

		__builtin_memset(storage->ca_name, 0, TCP_CA_NAME_MAX);

	} else {

		msk = bpf_skc_to_mptcp_sock(sk);

		if (!msk)
@@ -62,6 +64,7 @@ int _sockops(struct bpf_sock_ops *ctx) 
			return 1;



		storage->token = msk->token;

		__builtin_memcpy(storage->ca_name, msk->ca_name, TCP_CA_NAME_MAX);

	}

	storage->invoked++;

	storage->is_mptcp = is_mptcp;