Re: [PATCH 2/3] selftests/bpf: integrate test_xdp_veth into test_progs

On 07/11, Alexis Lothoré (eBPF Foundation) wrote:

test_xdp_veth.sh tests that XDP return codes work as expected, by bringing up multiple veth pairs isolated in different namespaces, attaching specific xdp programs to each interface, and ensuring that the whole chain allows to ping one end interface from the first one. The test runs well but is currently not integrated in test_progs, which prevents it from being run automatically in the CI infrastructure.

Rewrite it as a C test relying on libbpf to allow running it in the CI infrastructure. The new code brings up the same network infrastructure and reuses the same eBPF programs as test_xdp_veth.sh, for which skeletons are already generated by the bpf tests makefile.

Signed-off-by: Alexis Lothoré alexis.lothore@bootlin.com

The new code has been tested in an aarch64 qemu instance: Summary: 1/0 PASSED, 0 SKIPPED, 0 FAILED

I have also checked that some minor alterations in the network configuration (altering the redirect map, or not loading one of the xdp programs) make the test fail.

On my testing setup, the test takes a bit more than 3 seconds to run on average.

---

.../selftests/bpf/prog_tests/test_xdp_veth.c | 234 +++++++++++++++++++++ 1 file changed, 234 insertions(+)

diff --git a/tools/testing/selftests/bpf/prog_tests/test_xdp_veth.c b/tools/testing/selftests/bpf/prog_tests/test_xdp_veth.c new file mode 100644 index 000000000000..40d85aece984 --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/test_xdp_veth.c @@ -0,0 +1,234 @@ +// SPDX-License-Identifier: GPL-2.0 +/**

• • Create 3 namespaces with 3 veth peers, and
• • forward packets in-between using native XDP

• •                  XDP_TX
    

• • NS1(veth11) NS2(veth22) NS3(veth33)

• •  |                  |                  |
    

• •  |                  |                  |
    

• • (veth1, (veth2, (veth3,
• • id:111) id:122) id:133)

• • ^ |                ^ |                ^ |
    

• • | |  XDP_REDIRECT  | |  XDP_REDIRECT  | |
    

• • | ------------------ ------------------ |
    

• • -----------------------------------------
    

• •                XDP_REDIRECT
    

• */

+#define _GNU_SOURCE +#include <net/if.h> +#include "test_progs.h" +#include "network_helpers.h" +#include "xdp_dummy.skel.h" +#include "xdp_redirect_map.skel.h" +#include "xdp_tx.skel.h"

+#define VETH_PAIRS_COUNT 3 +#define NS_NAME_MAX_LEN 16 +#define NS_SUFFIX_LEN 6 +#define VETH_NAME_MAX_LEN 16 +#define IP_SRC "10.1.1.11" +#define IP_DST "10.1.1.33" +#define IP_CMD_MAX_LEN 128

+struct skeletons {

• struct xdp_dummy *xdp_dummy;
• struct xdp_tx *xdp_tx;
• struct xdp_redirect_map *xdp_redirect_maps;

+};

+struct veth_configuration {

• char local_veth[VETH_NAME_MAX_LEN]; /* Interface in main namespace */
• char remote_veth[VETH_NAME_MAX_LEN]; /* Peer interface in dedicated namespace*/
• char namespace[NS_NAME_MAX_LEN]; /* Namespace for the remote veth */
• char next_veth[VETH_NAME_MAX_LEN]; /* Local interface to redirect traffic to */
• char *remote_addr; /* IP address of the remote veth */

+};

+static struct veth_configuration config[VETH_PAIRS_COUNT] = {

• {

• .local_veth = "veth1",
  

• .remote_veth = "veth11",
  

• .next_veth = "veth2",
  

• .remote_addr = IP_SRC
  

• },
• {

• .local_veth = "veth2",
  

• .remote_veth = "veth22",
  

• .next_veth = "veth3",
  

• .remote_addr = NULL
  

• },
• {

• .local_veth = "veth3",
  

• .remote_veth = "veth33",
  

• .next_veth = "veth1",
  

• .remote_addr = IP_DST
  

• }

+};

[..]

+static void generate_random_ns_name(int index, char *out) +{

• int random, count, i;
• count = snprintf(out, NS_NAME_MAX_LEN, "ns%d-", index);
• for(i=0; i<NS_SUFFIX_LEN; i++) {

• random=rand() % 2;
  

• out[count++]= random ? 'a' + rand() % 26 : 'A' + rand() % 26;
  

• }
• out[count] = 0;

+}

It's been customary to hard-code netns names for all the tests we have, so maybe it's ok here as well?

+static int attach_programs_to_veth_pair(struct skeletons *skeletons, int index) +{

• struct bpf_program *local_prog, *remote_prog;
• struct bpf_link **local_link, **remote_link;
• struct nstoken *nstoken;
• struct bpf_link *link;
• int interface;

[..]

• switch(index) {

Can you pls run the patch through the checkpatch.pl? The formatting looks wrong, should be 'switch (index)'. Applies to 'if()' elsewhere as well.

• case 0:
  

• 	local_prog = skeletons->xdp_redirect_maps->progs.xdp_redirect_map_0;
  

• 	local_link = &skeletons->xdp_redirect_maps->links.xdp_redirect_map_0;
  

• 	remote_prog = skeletons->xdp_dummy->progs.xdp_dummy_prog;
  

• 	remote_link = &skeletons->xdp_dummy->links.xdp_dummy_prog;
  

• 	break;
  

• case 1:
  

• 	local_prog = skeletons->xdp_redirect_maps->progs.xdp_redirect_map_1;
  

• 	local_link = &skeletons->xdp_redirect_maps->links.xdp_redirect_map_1;
  

• 	remote_prog = skeletons->xdp_tx->progs.xdp_tx;
  

• 	remote_link = &skeletons->xdp_tx->links.xdp_tx;
  

• 	break;
  

• case 2:
  

• 	local_prog = skeletons->xdp_redirect_maps->progs.xdp_redirect_map_2;
  

• 	local_link = &skeletons->xdp_redirect_maps->links.xdp_redirect_map_2;
  

• 	remote_prog = skeletons->xdp_dummy->progs.xdp_dummy_prog;
  

• 	remote_link = &skeletons->xdp_dummy->links.xdp_dummy_prog;
  

• 	break;
  

• }
• interface = if_nametoindex(config[index].local_veth);
• if(!ASSERT_NEQ(interface, 0, "non zero interface index"))

• return -1;
  

• link = bpf_program__attach_xdp(local_prog, interface);
• if (!ASSERT_OK_PTR(link, "attach xdp program to local veth"))

• return -1;
  

• *local_link = link;
• nstoken = open_netns(config[index].namespace);
• if (!ASSERT_OK_PTR(nstoken, "switch to remote veth namespace"))

• return -1;
  

• interface = if_nametoindex(config[index].remote_veth);
• if(!ASSERT_NEQ(interface, 0, "non zero interface index"))

• return -1;
  

• link = bpf_program__attach_xdp(remote_prog, interface);
• *remote_link = link;
• close_netns(nstoken);
• if (!ASSERT_OK_PTR(link, "attach xdp program to remote veth"))

• return -1;
  

• return 0;

+}

+static int configure_network(struct skeletons *skeletons) {

• int interface_id;
• int map_fd;
• int err;
• int i=0;
• /* First create and configure all interfaces */
• for(i=0; i<VETH_PAIRS_COUNT; i++) {

• generate_random_ns_name(i+1, config[i].namespace);
  

• SYS(fail, "ip netns add %s", config[i].namespace);
  

• SYS(fail, "ip link add %s type veth peer name %s netns %s",
  

• 		config[i].local_veth,
  

• 		config[i].remote_veth,
  

• 		config[i].namespace);
  

• SYS(fail, "ip link set dev %s up", config[i].local_veth);
  

• if (config[i].remote_addr)
  

• 	SYS(fail, "ip -n %s addr add %s/24 dev %s",
  

• 			   config[i].namespace, config[i].remote_addr, config[i].remote_veth);
  

• SYS(fail, "ip -n %s link set dev %s up",
  

• 		   config[i].namespace, config[i].remote_veth);
  

• }
• /* Then configure the redirect map and attach programs to interfaces */
• map_fd = bpf_map__fd(skeletons->xdp_redirect_maps->maps.tx_port);
• if (!ASSERT_GE(map_fd, 0, "open redirect map"))

• goto fail;
  

• for (i=0; i<VETH_PAIRS_COUNT; i++) {

• interface_id = if_nametoindex(config[i].next_veth);
  

• if(!ASSERT_NEQ(interface_id, 0, "non zero interface index"))
  

• 	goto fail;
  

• err = bpf_map_update_elem(map_fd, &i, &interface_id, BPF_ANY);
  

• if (!ASSERT_OK(err, "configure interface redirection through map"))
  

• 	goto fail;
  

• if(attach_programs_to_veth_pair(skeletons, i))
  

• 	goto fail;
  

• }
• return 0;

+fail:

• return -1;

+}

+static void cleanup_network() +{

• char cmd[IP_CMD_MAX_LEN];
• int i;
• /* Deleting namespaces is enough to automatically remove veth pairs as well

• */
  

• for(i=0; i<VETH_PAIRS_COUNT; i++) {

• if(config[i].namespace[0] == 0)
  

• 	continue;
  

[..]

• snprintf(cmd, IP_CMD_MAX_LEN, "ip netns del %s", config[i].namespace);
  

• system(cmd);
  

SYS_NOFAIL to avoid separate snprintf?

• }

+}

+static int check_ping(struct skeletons *skeletons) +{

• char cmd[IP_CMD_MAX_LEN];
• /* Test: if all interfaces are properly configured, we must be able to ping

• * veth33 from veth11
  

• */
  

• snprintf(cmd, IP_CMD_MAX_LEN,

• 	 "ip netns exec %s ping -c 1 -W 1 %s > /dev/null",
  

• 	 config[0].namespace, IP_DST);
  

• return system(cmd);

SYS_NOFAL here as well?

Btw, not sure it makes sense to split that work into 3 patches. After you first patch the test is broken anyway, so might as well just delete the script at that point...