Commit 052c82dc authored by Martin KaFai Lau's avatar Martin KaFai Lau Committed by Daniel Borkmann
Browse files

selftests/bpf: Use if_nametoindex instead of reading the /sys/net/class/*/ifindex 



When switching netns, the setns_by_fd() is doing dances in mount/umounting
the /sys directories.  One reason is the tc_redirect.c test is depending
on the /sys/net/class/*/ifindex instead of using the if_nametoindex().
if_nametoindex() uses ioctl() to get the ifindex.

This patch is to move all /sys/net/class/*/ifindex usages to
if_nametoindex().  The current code checks ifindex >= 0 which is
incorrect.  ifindex > 0 should be checked instead.  This patch also
stores ifindex_veth_src and ifindex_veth_dst since the latter patch
will need them.

Signed-off-by: default avatarMartin KaFai Lau <martin.lau@kernel.org>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Acked-by: default avatarStanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/bpf/20221129070900.3142427-2-martin.lau@linux.dev
parent 91a7de85

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

+18 −28
Original line number Diff line number Diff line
@@ -11,12 +11,12 @@ 
 */



#include <arpa/inet.h>

#include <linux/if.h>

#include <linux/if_tun.h>

#include <linux/limits.h>

#include <linux/sysctl.h>

#include <linux/time_types.h>

#include <linux/net_tstamp.h>

#include <net/if.h>

#include <stdbool.h>

#include <stdio.h>

#include <sys/stat.h>
@@ -115,7 +115,9 @@ static void netns_setup_namespaces_nofail(const char *verb) 
}



struct netns_setup_result {

	int ifindex_veth_src;

	int ifindex_veth_src_fwd;

	int ifindex_veth_dst;

	int ifindex_veth_dst_fwd;

};
@@ -139,27 +141,6 @@ static int get_ifaddr(const char *name, char *ifaddr) 
	return 0;

}



static int get_ifindex(const char *name)

{

	char path[PATH_MAX];

	char buf[32];

	FILE *f;

	int ret;



	snprintf(path, PATH_MAX, "/sys/class/net/%s/ifindex", name);

	f = fopen(path, "r");

	if (!ASSERT_OK_PTR(f, path))

		return -1;



	ret = fread(buf, 1, sizeof(buf), f);

	if (!ASSERT_GT(ret, 0, "fread ifindex")) {

		fclose(f);

		return -1;

	}

	fclose(f);

	return atoi(buf);

}



#define SYS(fmt, ...)						\

	({							\

		char cmd[1024];					\
@@ -182,11 +163,20 @@ static int netns_setup_links_and_routes(struct netns_setup_result *result) 
	if (get_ifaddr("veth_src_fwd", veth_src_fwd_addr))

		goto fail;



	result->ifindex_veth_src_fwd = get_ifindex("veth_src_fwd");

	if (result->ifindex_veth_src_fwd < 0)

	result->ifindex_veth_src = if_nametoindex("veth_src");

	if (!ASSERT_GT(result->ifindex_veth_src, 0, "ifindex_veth_src"))

		goto fail;

	result->ifindex_veth_dst_fwd = get_ifindex("veth_dst_fwd");

	if (result->ifindex_veth_dst_fwd < 0)



	result->ifindex_veth_src_fwd = if_nametoindex("veth_src_fwd");

	if (!ASSERT_GT(result->ifindex_veth_src_fwd, 0, "ifindex_veth_src_fwd"))

		goto fail;



	result->ifindex_veth_dst = if_nametoindex("veth_dst");

	if (!ASSERT_GT(result->ifindex_veth_dst, 0, "ifindex_veth_dst"))

		goto fail;



	result->ifindex_veth_dst_fwd = if_nametoindex("veth_dst_fwd");

	if (!ASSERT_GT(result->ifindex_veth_dst_fwd, 0, "ifindex_veth_dst_fwd"))

		goto fail;



	SYS("ip link set veth_src netns " NS_SRC);
@@ -1034,8 +1024,8 @@ static void test_tc_redirect_peer_l3(struct netns_setup_result *setup_result) 
	if (!ASSERT_OK_PTR(skel, "test_tc_peer__open"))

		goto fail;



	ifindex = get_ifindex("tun_fwd");

	if (!ASSERT_GE(ifindex, 0, "get_ifindex tun_fwd"))

	ifindex = if_nametoindex("tun_fwd");

	if (!ASSERT_GT(ifindex, 0, "if_indextoname tun_fwd"))

		goto fail;



	skel->rodata->IFINDEX_SRC = ifindex;