Commit 8a3feed9 authored by Martin KaFai Lau's avatar Martin KaFai Lau Committed by Daniel Borkmann
Browse files

bpf, selftest: Fix flaky tcp_hdr_options test when adding addr to lo 



The tcp_hdr_options test adds a "::eB9F" addr to the lo dev.
However, this non loopback address will have a race on ipv6 dad
which may lead to EADDRNOTAVAIL error from time to time.

Even nodad is used in the iproute2 command, there is still a race in
when the route will be added.  This will then lead to ENETUNREACH from
time to time.

To avoid the above, this patch uses the default loopback address "::1"
to do the test.

Fixes: ad2f8eb0 ("bpf: selftests: Tcp header options")
Reported-by: default avatarAndrii Nakryiko <andriin@fb.com>
Signed-off-by: default avatarMartin KaFai Lau <kafai@fb.com>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Acked-by: default avatarAndrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20201012234940.1707941-1-kafai@fb.com
parent f58423ae

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

+1 −25
Original line number Diff line number Diff line
@@ -15,7 +15,7 @@ 
#include "test_tcp_hdr_options.skel.h"

#include "test_misc_tcp_hdr_options.skel.h"



#define LO_ADDR6 "::eB9F"

#define LO_ADDR6 "::1"

#define CG_NAME "/tcpbpf-hdr-opt-test"



struct bpf_test_option exp_passive_estab_in;
@@ -40,27 +40,6 @@ struct sk_fds { 
	int active_lport;

};



static int add_lo_addr(void)

{

	char ip_addr_cmd[256];

	int cmdlen;



	cmdlen = snprintf(ip_addr_cmd, sizeof(ip_addr_cmd),

			  "ip -6 addr add %s/128 dev lo scope host",

			  LO_ADDR6);



	if (CHECK(cmdlen >= sizeof(ip_addr_cmd), "compile ip cmd",

		  "failed to add host addr %s to lo. ip cmdlen is too long\n",

		  LO_ADDR6))

		return -1;



	if (CHECK(system(ip_addr_cmd), "run ip cmd",

		  "failed to add host addr %s to lo\n", LO_ADDR6))

		return -1;



	return 0;

}



static int create_netns(void)

{

	if (CHECK(unshare(CLONE_NEWNET), "create netns",
@@ -72,9 +51,6 @@ static int create_netns(void) 
		  "failed to bring lo link up\n"))

		return -1;



	if (add_lo_addr())

		return -1;



	return 0;

}

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

+1 −1
Original line number Diff line number Diff line
@@ -16,7 +16,7 @@ 
#define BPF_PROG_TEST_TCP_HDR_OPTIONS

#include "test_tcp_hdr_options.h"



__u16 last_addr16_n = __bpf_htons(0xeB9F);

__u16 last_addr16_n = __bpf_htons(1);

__u16 active_lport_n = 0;

__u16 active_lport_h = 0;

__u16 passive_lport_n = 0;

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