Subject: Re: [PATCH bpf,v3 4/4] selftests/bpf: Add vrf_socket_lookup tests

From: Stanislav Fomichev <[email-masked]>
Date: Thu, 27 Apr 2023 10:31:36 -0700

On 04/26, Gilad Sever wrote:
> Verify that socket lookup via TC/XDP with all BPF APIs is VRF aware.
> 
> Reviewed-by: Eyal Birger <[email-masked]>
> Signed-off-by: Gilad Sever <[email-masked]>
> ---
> v2: Fix build by initializing vars with -1
> ---
> v3: Added xdp tests as suggested by Daniel Borkmann
> v3: Use start_server() to avoid duplicate code as suggested by
>     Stanislav Fomichev
> ---
>  .../bpf/prog_tests/vrf_socket_lookup.c        | 327 ++++++++++++++++++
>  .../selftests/bpf/progs/vrf_socket_lookup.c   |  88 +++++
>  2 files changed, 415 insertions(+)
>  create mode 100644 tools/testing/selftests/bpf/prog_tests/vrf_socket_lookup.c
>  create mode 100644 tools/testing/selftests/bpf/progs/vrf_socket_lookup.c
> 
> diff --git a/tools/testing/selftests/bpf/prog_tests/vrf_socket_lookup.c b/tools/testing/selftests/bpf/prog_tests/vrf_socket_lookup.c
> new file mode 100644
> index 000000000000..b0b8791f4968
> --- /dev/null
> +++ b/tools/testing/selftests/bpf/prog_tests/vrf_socket_lookup.c
> @@ -0,0 +1,327 @@
> +// SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
> +
> +/*
> + * Topology:
> + * ---------
> + *     NS0 namespace         |   NS1 namespace
> + *			     |
> + *     +--------------+      |   +--------------+
> + *     |    veth01    |----------|    veth10    |
> + *     | 172.16.1.100 |      |   | 172.16.1.200 |
> + *     |     bpf      |      |   +--------------+
> + *     +--------------+      |
> + *      server(UDP/TCP)      |
> + *  +-------------------+    |
> + *  |        vrf1       |    |
> + *  |  +--------------+ |    |   +--------------+
> + *  |  |    veth02    |----------|    veth20    |
> + *  |  | 172.16.2.100 | |    |   | 172.16.2.200 |
> + *  |  |     bpf      | |    |   +--------------+
> + *  |  +--------------+ |    |
> + *  |   server(UDP/TCP) |    |
> + *  +-------------------+    |
> + *
> + * Test flow
> + * -----------
> + *  The tests verifies that socket lookup via TC is VRF aware:
> + *  1) Creates two veth pairs between NS0 and NS1:
> + *     a) veth01 <-> veth10 outside the VRF
> + *     b) veth02 <-> veth20 in the VRF
> + *  2) Attaches to veth01 and veth02 a program that calls:
> + *     a) bpf_skc_lookup_tcp() with TCP and tcp_skc is true
> + *     b) bpf_sk_lookup_tcp() with TCP and tcp_skc is false
> + *     c) bpf_sk_lookup_udp() with UDP
> + *     The program stores the lookup result in bss->lookup_status.
> + *  3) Creates a socket TCP/UDP server in/outside the VRF.
> + *  4) The test expects lookup_status to be:
> + *     a) 0 from device in VRF to server outside VRF
> + *     b) 0 from device outside VRF to server in VRF
> + *     c) 1 from device in VRF to server in VRF
> + *     d) 1 from device outside VRF to server outside VRF
> + */
> +
> +#include <net/if.h>
> +
> +#include "test_progs.h"
> +#include "network_helpers.h"
> +#include "vrf_socket_lookup.skel.h"
> +
> +#define NS0 "vrf_socket_lookup_0"
> +#define NS1 "vrf_socket_lookup_1"
> +
> +#define IP4_ADDR_VETH01 "172.16.1.100"
> +#define IP4_ADDR_VETH10 "172.16.1.200"
> +#define IP4_ADDR_VETH02 "172.16.2.100"
> +#define IP4_ADDR_VETH20 "172.16.2.200"
> +
> +#define NON_VRF_PORT 5000
> +#define IN_VRF_PORT 5001
> +
> +#define TIMEOUT_MS 3000
> +
> +#define SYS(fmt, ...)						\
> +	({							\
> +		char cmd[1024];					\
> +		snprintf(cmd, sizeof(cmd), fmt, ##__VA_ARGS__);	\
> +		if (!ASSERT_OK(system(cmd), cmd))		\
> +			goto fail;				\
> +	})
> +

The bot complains about SYS being redefined:
   /tmp/work/bpf/bpf/tools/testing/selftests/bpf/prog_tests/vrf_socket_lookup.c:62: error: "SYS" redefined [-Werror]
     62 | #define SYS(fmt, ...)      \
        | 
  In file included from /tmp/work/bpf/bpf/tools/testing/selftests/bpf/prog_tests/vrf_socket_lookup.c:45:
  ./test_progs.h:380: note: this is the location of the previous definition
    380 | #define SYS(goto_label, fmt, ...)     \

Looks like test_progs.h already defines it (along with SYS_NOFAIL).

> +#define SYS_NOFAIL(fmt, ...)					\
> +	({							\
> +		char cmd[1024];					\
> +		snprintf(cmd, sizeof(cmd), fmt, ##__VA_ARGS__);	\
> +		system(cmd);					\
> +	})
> +
> +static int make_socket(int sotype, const char *ip, int port,
> +		       struct sockaddr_storage *addr)
> +{
> +	int err, fd;
> +
> +	err = make_sockaddr(AF_INET, ip, port, addr, NULL);
> +	if (!ASSERT_OK(err, "make_address"))
> +		return -1;
> +
> +	fd = socket(AF_INET, sotype, 0);
> +	if (!ASSERT_GE(fd, 0, "socket"))
> +		return -1;
> +
> +	if (!ASSERT_OK(settimeo(fd, TIMEOUT_MS), "settimeo"))
> +		goto fail;
> +
> +	return fd;
> +fail:
> +	close(fd);
> +	return -1;
> +}
> +
> +static int make_server(int sotype, const char *ip, int port, const char *ifname)
> +{
> +	int err, fd = -1;
> +
> +	fd = start_server(AF_INET, sotype, ip, port, TIMEOUT_MS);
> +	if (!ASSERT_GE(fd, 0, "start_server"))
> +		return -1;
> +
> +	if (ifname) {
> +		err = setsockopt(fd, SOL_SOCKET, SO_BINDTODEVICE,
> +				 ifname, strlen(ifname) + 1);
> +		if (!ASSERT_OK(err, "setsockopt(SO_BINDTODEVICE)"))
> +			goto fail;
> +	}
> +
> +	return fd;
> +fail:
> +	close(fd);
> +	return -1;
> +}
> +
> +static int attach_progs(char *ifname, int tc_prog_fd, int xdp_prog_fd)
> +{
> +	LIBBPF_OPTS(bpf_tc_opts, opts, .handle = 1, .priority = 1,
> +		    .prog_fd = tc_prog_fd);
> +	LIBBPF_OPTS(bpf_tc_hook, hook, .attach_point = BPF_TC_INGRESS);
> +	int ret, ifindex;
> +
> +	ifindex = if_nametoindex(ifname);
> +	if (!ASSERT_NEQ(ifindex, 0, "if_nametoindex"))
> +		return -1;
> +	hook.ifindex = ifindex;
> +
> +	ret = bpf_tc_hook_create(&hook);
> +	if (!ASSERT_OK(ret, "bpf_tc_hook_create"))
> +		return ret;
> +
> +	ret = bpf_tc_attach(&hook, &opts);
> +	if (!ASSERT_OK(ret, "bpf_tc_attach")) {
> +		bpf_tc_hook_destroy(&hook);
> +		return ret;
> +	}
> +	ret = bpf_xdp_attach(ifindex, xdp_prog_fd, 0, NULL);
> +	if (!ASSERT_OK(ret, "bpf_xdp_attach")) {
> +		bpf_tc_hook_destroy(&hook);
> +		return ret;
> +	}
> +
> +	return 0;
> +}
> +
> +static void cleanup(void)
> +{
> +	SYS_NOFAIL("test -f /var/run/netns/" NS0 " && ip netns delete "
> +		   NS0);
> +	SYS_NOFAIL("test -f /var/run/netns/" NS1 " && ip netns delete "
> +		   NS1);
> +}
> +
> +static int setup(struct vrf_socket_lookup *skel)
> +{
> +	int tc_prog_fd, xdp_prog_fd, ret = 0;
> +	struct nstoken *nstoken = NULL;
> +
> +	SYS("ip netns add " NS0);
> +	SYS("ip netns add " NS1);
> +
> +	/* NS0 <-> NS1 [veth01 <-> veth10] */
> +	SYS("ip link add veth01 netns " NS0 " type veth peer name veth10 netns "
> +	    NS1);
> +	SYS("ip -net " NS0 " addr add " IP4_ADDR_VETH01 "/24 dev veth01");
> +	SYS("ip -net " NS0 " link set dev veth01 up");
> +	SYS("ip -net " NS1 " addr add " IP4_ADDR_VETH10 "/24 dev veth10");
> +	SYS("ip -net " NS1 " link set dev veth10 up");
> +
> +	/* NS0 <-> NS1 [veth02 <-> veth20] */
> +	SYS("ip link add veth02 netns " NS0 " type veth peer name veth20 netns "
> +	    NS1);
> +	SYS("ip -net " NS0 " addr add " IP4_ADDR_VETH02 "/24 dev veth02");
> +	SYS("ip -net " NS0 " link set dev veth02 up");
> +	SYS("ip -net " NS1 " addr add " IP4_ADDR_VETH20 "/24 dev veth20");
> +	SYS("ip -net " NS1 " link set dev veth20 up");
> +
> +	/* veth02 -> vrf1  */
> +	SYS("ip -net " NS0 " link add vrf1 type vrf table 11");
> +	SYS("ip -net " NS0 " route add vrf vrf1 unreachable default metric "
> +	    "4278198272");
> +	SYS("ip -net " NS0 " link set vrf1 alias vrf");
> +	SYS("ip -net " NS0 " link set vrf1 up");
> +	SYS("ip -net " NS0 " link set veth02 master vrf1");
> +
> +	/* Attach TC and XDP progs to veth devices in NS0 */
> +	nstoken = open_netns(NS0);
> +	if (!ASSERT_OK_PTR(nstoken, "setns " NS0))
> +		goto fail;
> +	tc_prog_fd = bpf_program__fd(skel->progs.tc_socket_lookup);
> +	if (!ASSERT_GE(tc_prog_fd, 0, "bpf_program__tc_fd"))
> +		goto fail;
> +	xdp_prog_fd = bpf_program__fd(skel->progs.xdp_socket_lookup);
> +	if (!ASSERT_GE(xdp_prog_fd, 0, "bpf_program__xdp_fd"))
> +		goto fail;
> +
> +	if (attach_progs("veth01", tc_prog_fd, xdp_prog_fd))
> +		goto fail;
> +
> +	if (attach_progs("veth02", tc_prog_fd, xdp_prog_fd))
> +		goto fail;
> +
> +	goto close;
> +fail:
> +	ret = -1;
> +close:
> +	if (nstoken)
> +		close_netns(nstoken);
> +	return ret;
> +}
> +
> +static int test_lookup(struct vrf_socket_lookup *skel, int sotype,
> +		       const char *ip, int port, bool test_xdp, bool tcp_skc,
> +		       int lookup_status_exp)
> +{
> +	static const char msg[] = "Hello Server";
> +	struct sockaddr_storage addr = {};
> +	int fd, ret = 0;
> +
> +	fd = make_socket(sotype, ip, port, &addr);
> +	if (fd < 0)
> +		return -1;
> +
> +	skel->bss->test_xdp = test_xdp;
> +	skel->bss->tcp_skc = tcp_skc;
> +	skel->bss->lookup_status = -1;
> +
> +	if (sotype == SOCK_STREAM)
> +		connect(fd, (void *)&addr, sizeof(struct sockaddr_in));
> +	else
> +		sendto(fd, msg, sizeof(msg), 0, (void *)&addr,
> +		       sizeof(struct sockaddr_in));
> +
> +	if (!ASSERT_EQ(skel->bss->lookup_status, lookup_status_exp,
> +		       "lookup_status"))
> +		goto fail;
> +
> +	goto close;
> +
> +fail:
> +	ret = -1;
> +close:
> +	close(fd);
> +	return ret;
> +}
> +
> +static void _test_vrf_socket_lookup(struct vrf_socket_lookup *skel, int sotype,
> +				    bool test_xdp, bool tcp_skc)
> +{
> +	int in_vrf_server = -1, non_vrf_server = -1;
> +	struct nstoken *nstoken = NULL;
> +
> +	nstoken = open_netns(NS0);
> +	if (!ASSERT_OK_PTR(nstoken, "setns " NS0))
> +		goto done;
> +
> +	/* Open sockets in and outside VRF */
> +	non_vrf_server = make_server(sotype, "0.0.0.0", NON_VRF_PORT, NULL);
> +	if (!ASSERT_GE(non_vrf_server, 0, "make_server__outside_vrf_fd"))
> +		goto done;
> +
> +	in_vrf_server = make_server(sotype, "0.0.0.0", IN_VRF_PORT, "veth02");
> +	if (!ASSERT_GE(in_vrf_server, 0, "make_server__in_vrf_fd"))
> +		goto done;
> +
> +	/* Perform test from NS1 */
> +	close_netns(nstoken);
> +	nstoken = open_netns(NS1);
> +	if (!ASSERT_OK_PTR(nstoken, "setns " NS1))
> +		goto done;
> +
> +	if (!ASSERT_OK(test_lookup(skel, sotype, IP4_ADDR_VETH02, NON_VRF_PORT,
> +				   test_xdp, tcp_skc, 0), "in_to_out"))
> +		goto done;
> +	if (!ASSERT_OK(test_lookup(skel, sotype, IP4_ADDR_VETH02, IN_VRF_PORT,
> +				   test_xdp, tcp_skc, 1), "in_to_in"))
> +		goto done;
> +	if (!ASSERT_OK(test_lookup(skel, sotype, IP4_ADDR_VETH01, NON_VRF_PORT,
> +				   test_xdp, tcp_skc, 1), "out_to_out"))
> +		goto done;
> +	if (!ASSERT_OK(test_lookup(skel, sotype, IP4_ADDR_VETH01, IN_VRF_PORT,
> +				   test_xdp, tcp_skc, 0), "out_to_in"))
> +		goto done;
> +
> +done:
> +	if (non_vrf_server >= 0)
> +		close(non_vrf_server);
> +	if (in_vrf_server >= 0)
> +		close(in_vrf_server);
> +	if (nstoken)
> +		close_netns(nstoken);
> +}
> +
> +void test_vrf_socket_lookup(void)
> +{
> +	struct vrf_socket_lookup *skel;
> +
> +	cleanup();
> +
> +	skel = vrf_socket_lookup__open_and_load();
> +	if (!ASSERT_OK_PTR(skel, "vrf_socket_lookup__open_and_load"))
> +		return;
> +
> +	if (!ASSERT_OK(setup(skel), "setup"))
> +		goto done;
> +
> +	if (test__start_subtest("tc_socket_lookup_tcp"))
> +		_test_vrf_socket_lookup(skel, SOCK_STREAM, false, false);
> +	if (test__start_subtest("tc_socket_lookup_tcp_skc"))
> +		_test_vrf_socket_lookup(skel, SOCK_STREAM, false, false);
> +	if (test__start_subtest("tc_socket_lookup_udp"))
> +		_test_vrf_socket_lookup(skel, SOCK_STREAM, false, false);
> +	if (test__start_subtest("xdp_socket_lookup_tcp"))
> +		_test_vrf_socket_lookup(skel, SOCK_STREAM, true, false);
> +	if (test__start_subtest("xdp_socket_lookup_tcp_skc"))
> +		_test_vrf_socket_lookup(skel, SOCK_STREAM, true, false);
> +	if (test__start_subtest("xdp_socket_lookup_udp"))
> +		_test_vrf_socket_lookup(skel, SOCK_STREAM, true, false);
> +
> +done:
> +	vrf_socket_lookup__destroy(skel);
> +	cleanup();
> +}
> diff --git a/tools/testing/selftests/bpf/progs/vrf_socket_lookup.c b/tools/testing/selftests/bpf/progs/vrf_socket_lookup.c
> new file mode 100644
> index 000000000000..26e07a252585
> --- /dev/null
> +++ b/tools/testing/selftests/bpf/progs/vrf_socket_lookup.c
> @@ -0,0 +1,88 @@
> +// SPDX-License-Identifier: GPL-2.0
> +#include <linux/bpf.h>
> +#include <linux/ip.h>
> +#include <linux/in.h>
> +#include <linux/if_ether.h>
> +#include <linux/pkt_cls.h>
> +#include <bpf/bpf_helpers.h>
> +#include <bpf/bpf_endian.h>
> +#include <stdbool.h>
> +
> +int lookup_status;
> +bool test_xdp;
> +bool tcp_skc;
> +
> +#define CUR_NS BPF_F_CURRENT_NETNS
> +
> +static void socket_lookup(void *ctx, void *data_end, void *data)
> +{
> +	struct ethhdr *eth = data;
> +	struct bpf_sock_tuple *tp;
> +	struct bpf_sock *sk;
> +	struct iphdr *iph;
> +	int tplen;
> +
> +	if (eth + 1 > data_end)
> +		return;
> +
> +	if (eth->h_proto != bpf_htons(ETH_P_IP))
> +		return;
> +
> +	iph = (struct iphdr *)(eth + 1);
> +	if (iph + 1 > data_end)
> +		return;
> +
> +	tp = (struct bpf_sock_tuple *)&iph->saddr;
> +	tplen = sizeof(tp->ipv4);
> +	if ((void *)tp + tplen > data_end)
> +		return;
> +
> +	switch (iph->protocol) {
> +	case IPPROTO_TCP:
> +		if (tcp_skc)
> +			sk = bpf_skc_lookup_tcp(ctx, tp, tplen, CUR_NS, 0);
> +		else
> +			sk = bpf_sk_lookup_tcp(ctx, tp, tplen, CUR_NS, 0);
> +		break;
> +	case IPPROTO_UDP:
> +		sk = bpf_sk_lookup_udp(ctx, tp, tplen, CUR_NS, 0);
> +		break;
> +	default:
> +		return;
> +	}
> +
> +	lookup_status = 0;
> +
> +	if (sk) {
> +		bpf_sk_release(sk);
> +		lookup_status = 1;
> +	}
> +}
> +
> +SEC("tc")
> +int tc_socket_lookup(struct __sk_buff *skb)
> +{
> +	void *data_end = (void *)(long)skb->data_end;
> +	void *data = (void *)(long)skb->data;
> +
> +	if (test_xdp)
> +		return TC_ACT_UNSPEC;
> +
> +	socket_lookup(skb, data_end, data);
> +	return TC_ACT_UNSPEC;
> +}
> +
> +SEC("xdp")
> +int xdp_socket_lookup(struct xdp_md *xdp)
> +{
> +	void *data_end = (void *)(long)xdp->data_end;
> +	void *data = (void *)(long)xdp->data;
> +
> +	if (!test_xdp)
> +		return XDP_PASS;
> +
> +	socket_lookup(xdp, data_end, data);
> +	return XDP_PASS;
> +}
> +
> +char _license[] SEC("license") = "GPL";
> -- 
> 2.34.1
>