From 0ae362f376cf4d05851f4c426207065b2df14abc Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Alexis=20Lothor=C3=A9=20=28eBPF=20Foundation=29?=
 <alexis.lothore@bootlin.com>
Date: Wed, 22 Oct 2025 09:39:50 +0200
Subject: [PATCH 1/4] selftests/bpf: add tc helpers
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

The test_tunnel.c file defines small fonctions to easily attach eBPF
programs to tc hooks, either on egress, ingress or both.

Create a shared helper in network_helpers.c so that other tests can
benefit from it.

Signed-off-by: Alexis Lothoré (eBPF Foundation) <alexis.lothore@bootlin.com>
---
 tools/testing/selftests/bpf/network_helpers.c |  45 ++++++++
 tools/testing/selftests/bpf/network_helpers.h |  16 +++
 .../selftests/bpf/prog_tests/test_tunnel.c    | 107 +++---------------
 3 files changed, 75 insertions(+), 93 deletions(-)

diff --git a/tools/testing/selftests/bpf/network_helpers.c b/tools/testing/selftests/bpf/network_helpers.c
index cdf7b66414442..0998d71fe57a3 100644
--- a/tools/testing/selftests/bpf/network_helpers.c
+++ b/tools/testing/selftests/bpf/network_helpers.c
@@ -766,6 +766,51 @@ int send_recv_data(int lfd, int fd, uint32_t total_bytes)
 	return err;
 }
 
+int tc_prog_attach(const char *dev, int ingress_fd, int egress_fd)
+{
+	int ifindex;
+
+	if (!ASSERT_TRUE(ingress_fd >= 0 || egress_fd >= 0,
+			 "at least one program fd is valid"))
+		return -1;
+
+	ifindex = if_nametoindex(dev);
+	if (!ASSERT_NEQ(ifindex, 0, "get ifindex"))
+		return -1;
+
+	DECLARE_LIBBPF_OPTS(bpf_tc_hook, hook, .ifindex = ifindex,
+			    .attach_point = BPF_TC_INGRESS | BPF_TC_EGRESS);
+	DECLARE_LIBBPF_OPTS(bpf_tc_opts, opts1, .handle = 1,
+			    .priority = 1, .prog_fd = ingress_fd);
+	DECLARE_LIBBPF_OPTS(bpf_tc_opts, opts2, .handle = 1,
+			    .priority = 1, .prog_fd = egress_fd);
+	int ret;
+
+	ret = bpf_tc_hook_create(&hook);
+	if (!ASSERT_OK(ret, "create tc hook"))
+		return ret;
+
+	if (ingress_fd >= 0) {
+		hook.attach_point = BPF_TC_INGRESS;
+		ret = bpf_tc_attach(&hook, &opts1);
+		if (!ASSERT_OK(ret, "bpf_tc_attach")) {
+			bpf_tc_hook_destroy(&hook);
+			return ret;
+		}
+	}
+
+	if (egress_fd >= 0) {
+		hook.attach_point = BPF_TC_EGRESS;
+		ret = bpf_tc_attach(&hook, &opts2);
+		if (!ASSERT_OK(ret, "bpf_tc_attach")) {
+			bpf_tc_hook_destroy(&hook);
+			return ret;
+		}
+	}
+
+	return 0;
+}
+
 #ifdef TRAFFIC_MONITOR
 struct tmonitor_ctx {
 	pcap_t *pcap;
diff --git a/tools/testing/selftests/bpf/network_helpers.h b/tools/testing/selftests/bpf/network_helpers.h
index ef208eefd571a..79a010c88e11c 100644
--- a/tools/testing/selftests/bpf/network_helpers.h
+++ b/tools/testing/selftests/bpf/network_helpers.h
@@ -255,6 +255,22 @@ struct tmonitor_ctx;
 
 typedef int (*tm_print_fn_t)(const char *format, va_list args);
 
+/**
+ * tc_prog_attach - attach BPF program(s) to an interface
+ *
+ * Takes file descriptors pointing to at least one, at most two BPF
+ * programs, and attach those programs to an interface ingress, egress or
+ * both.
+ *
+ * @dev: string containing the interface name
+ * @ingress_fd: file descriptor of the program to attach to interface ingress
+ * @egress_fd: file descriptor of the program to attach to interface egress
+ *
+ * Returns 0 on success, -1 if no valid file descriptor has been found, if
+ * the interface name is invalid or if an error ocurred during attach.
+ */
+int tc_prog_attach(const char *dev, int ingress_fd, int egress_fd);
+
 #ifdef TRAFFIC_MONITOR
 struct tmonitor_ctx *traffic_monitor_start(const char *netns, const char *test_name,
 					   const char *subtest_name);
diff --git a/tools/testing/selftests/bpf/prog_tests/test_tunnel.c b/tools/testing/selftests/bpf/prog_tests/test_tunnel.c
index bae0e9de277d2..eb93099312720 100644
--- a/tools/testing/selftests/bpf/prog_tests/test_tunnel.c
+++ b/tools/testing/selftests/bpf/prog_tests/test_tunnel.c
@@ -534,85 +534,6 @@ static void ping6_dev1(void)
 	close_netns(nstoken);
 }
 
-static int attach_tc_prog(int ifindex, int igr_fd, int egr_fd)
-{
-	DECLARE_LIBBPF_OPTS(bpf_tc_hook, hook, .ifindex = ifindex,
-			    .attach_point = BPF_TC_INGRESS | BPF_TC_EGRESS);
-	DECLARE_LIBBPF_OPTS(bpf_tc_opts, opts1, .handle = 1,
-			    .priority = 1, .prog_fd = igr_fd);
-	DECLARE_LIBBPF_OPTS(bpf_tc_opts, opts2, .handle = 1,
-			    .priority = 1, .prog_fd = egr_fd);
-	int ret;
-
-	ret = bpf_tc_hook_create(&hook);
-	if (!ASSERT_OK(ret, "create tc hook"))
-		return ret;
-
-	if (igr_fd >= 0) {
-		hook.attach_point = BPF_TC_INGRESS;
-		ret = bpf_tc_attach(&hook, &opts1);
-		if (!ASSERT_OK(ret, "bpf_tc_attach")) {
-			bpf_tc_hook_destroy(&hook);
-			return ret;
-		}
-	}
-
-	if (egr_fd >= 0) {
-		hook.attach_point = BPF_TC_EGRESS;
-		ret = bpf_tc_attach(&hook, &opts2);
-		if (!ASSERT_OK(ret, "bpf_tc_attach")) {
-			bpf_tc_hook_destroy(&hook);
-			return ret;
-		}
-	}
-
-	return 0;
-}
-
-static int generic_attach(const char *dev, int igr_fd, int egr_fd)
-{
-	int ifindex;
-
-	if (!ASSERT_OK_FD(igr_fd, "check ingress fd"))
-		return -1;
-	if (!ASSERT_OK_FD(egr_fd, "check egress fd"))
-		return -1;
-
-	ifindex = if_nametoindex(dev);
-	if (!ASSERT_NEQ(ifindex, 0, "get ifindex"))
-		return -1;
-
-	return attach_tc_prog(ifindex, igr_fd, egr_fd);
-}
-
-static int generic_attach_igr(const char *dev, int igr_fd)
-{
-	int ifindex;
-
-	if (!ASSERT_OK_FD(igr_fd, "check ingress fd"))
-		return -1;
-
-	ifindex = if_nametoindex(dev);
-	if (!ASSERT_NEQ(ifindex, 0, "get ifindex"))
-		return -1;
-
-	return attach_tc_prog(ifindex, igr_fd, -1);
-}
-
-static int generic_attach_egr(const char *dev, int egr_fd)
-{
-	int ifindex;
-
-	if (!ASSERT_OK_FD(egr_fd, "check egress fd"))
-		return -1;
-
-	ifindex = if_nametoindex(dev);
-	if (!ASSERT_NEQ(ifindex, 0, "get ifindex"))
-		return -1;
-
-	return attach_tc_prog(ifindex, -1, egr_fd);
-}
-
 static void test_vxlan_tunnel(void)
 {
 	struct test_tunnel_kern *skel = NULL;
@@ -635,12 +556,12 @@ static void test_vxlan_tunnel(void)
 		goto done;
 	get_src_prog_fd = bpf_program__fd(skel->progs.vxlan_get_tunnel_src);
 	set_src_prog_fd = bpf_program__fd(skel->progs.vxlan_set_tunnel_src);
-	if (generic_attach(VXLAN_TUNL_DEV1, get_src_prog_fd, set_src_prog_fd))
+	if (tc_prog_attach(VXLAN_TUNL_DEV1, get_src_prog_fd, set_src_prog_fd))
 		goto done;
 
 	/* load and attach bpf prog to veth dev tc hook point */
 	set_dst_prog_fd = bpf_program__fd(skel->progs.veth_set_outer_dst);
-	if (generic_attach_igr("veth1", set_dst_prog_fd))
+	if (tc_prog_attach("veth1", set_dst_prog_fd, -1))
 		goto done;
 
 	/* load and attach prog set_md to tunnel dev tc hook point at_ns0 */
@@ -648,7 +569,7 @@ static void test_vxlan_tunnel(void)
 	if (!ASSERT_OK_PTR(nstoken, "setns src"))
 		goto done;
 	set_dst_prog_fd = bpf_program__fd(skel->progs.vxlan_set_tunnel_dst);
-	if (generic_attach_egr(VXLAN_TUNL_DEV0, set_dst_prog_fd))
+	if (tc_prog_attach(VXLAN_TUNL_DEV0, -1, set_dst_prog_fd))
 		goto done;
 	close_netns(nstoken);
 
@@ -695,7 +616,7 @@ static void test_ip6vxlan_tunnel(void)
 		goto done;
 	get_src_prog_fd = bpf_program__fd(skel->progs.ip6vxlan_get_tunnel_src);
 	set_src_prog_fd = bpf_program__fd(skel->progs.ip6vxlan_set_tunnel_src);
-	if (generic_attach(IP6VXLAN_TUNL_DEV1, get_src_prog_fd, set_src_prog_fd))
+	if (tc_prog_attach(IP6VXLAN_TUNL_DEV1, get_src_prog_fd, set_src_prog_fd))
 		goto done;
 
 	/* load and attach prog set_md to tunnel dev tc hook point at_ns0 */
@@ -703,7 +624,7 @@ static void test_ip6vxlan_tunnel(void)
 	if (!ASSERT_OK_PTR(nstoken, "setns src"))
 		goto done;
 	set_dst_prog_fd = bpf_program__fd(skel->progs.ip6vxlan_set_tunnel_dst);
-	if (generic_attach_egr(IP6VXLAN_TUNL_DEV0, set_dst_prog_fd))
+	if (tc_prog_attach(IP6VXLAN_TUNL_DEV0, -1, set_dst_prog_fd))
 		goto done;
 	close_netns(nstoken);
 
@@ -764,7 +685,7 @@ static void test_ipip_tunnel(enum ipip_encap encap)
 			skel->progs.ipip_set_tunnel);
 	}
 
-	if (generic_attach(IPIP_TUNL_DEV1, get_src_prog_fd, set_src_prog_fd))
+	if (tc_prog_attach(IPIP_TUNL_DEV1, get_src_prog_fd, set_src_prog_fd))
 		goto done;
 
 	ping_dev0();
@@ -797,7 +718,7 @@ static void test_xfrm_tunnel(void)
 
 	/* attach tc prog to tunnel dev */
 	tc_prog_fd = bpf_program__fd(skel->progs.xfrm_get_state);
-	if (generic_attach_igr("veth1", tc_prog_fd))
+	if (tc_prog_attach("veth1", tc_prog_fd, -1))
 		goto done;
 
 	/* attach xdp prog to tunnel dev */
@@ -870,7 +791,7 @@ static void test_gre_tunnel(enum gre_test test)
 	if (!ASSERT_OK(err, "add tunnel"))
 		goto done;
 
-	if (generic_attach(GRE_TUNL_DEV1, get_fd, set_fd))
+	if (tc_prog_attach(GRE_TUNL_DEV1, get_fd, set_fd))
 		goto done;
 
 	ping_dev0();
@@ -911,7 +832,7 @@ static void test_ip6gre_tunnel(enum ip6gre_test test)
 
 	set_fd = bpf_program__fd(skel->progs.ip6gretap_set_tunnel);
 	get_fd = bpf_program__fd(skel->progs.ip6gretap_get_tunnel);
-	if (generic_attach(IP6GRE_TUNL_DEV1, get_fd, set_fd))
+	if (tc_prog_attach(IP6GRE_TUNL_DEV1, get_fd, set_fd))
 		goto done;
 
 	ping6_veth0();
@@ -954,7 +875,7 @@ static void test_erspan_tunnel(enum erspan_test test)
 
 	set_fd = bpf_program__fd(skel->progs.erspan_set_tunnel);
 	get_fd = bpf_program__fd(skel->progs.erspan_get_tunnel);
-	if (generic_attach(ERSPAN_TUNL_DEV1, get_fd, set_fd))
+	if (tc_prog_attach(ERSPAN_TUNL_DEV1, get_fd, set_fd))
 		goto done;
 
 	ping_dev0();
@@ -990,7 +911,7 @@ static void test_ip6erspan_tunnel(enum erspan_test test)
 
 	set_fd = bpf_program__fd(skel->progs.ip4ip6erspan_set_tunnel);
 	get_fd = bpf_program__fd(skel->progs.ip4ip6erspan_get_tunnel);
-	if (generic_attach(IP6ERSPAN_TUNL_DEV1, get_fd, set_fd))
+	if (tc_prog_attach(IP6ERSPAN_TUNL_DEV1, get_fd, set_fd))
 		goto done;
 
 	ping6_veth0();
@@ -1017,7 +938,7 @@ static void test_geneve_tunnel(void)
 
 	set_fd = bpf_program__fd(skel->progs.geneve_set_tunnel);
 	get_fd = bpf_program__fd(skel->progs.geneve_get_tunnel);
-	if (generic_attach(GENEVE_TUNL_DEV1, get_fd, set_fd))
+	if (tc_prog_attach(GENEVE_TUNL_DEV1, get_fd, set_fd))
 		goto done;
 
 	ping_dev0();
@@ -1044,7 +965,7 @@ static void test_ip6geneve_tunnel(void)
 
 	set_fd = bpf_program__fd(skel->progs.ip6geneve_set_tunnel);
 	get_fd = bpf_program__fd(skel->progs.ip6geneve_get_tunnel);
-	if (generic_attach(IP6GENEVE_TUNL_DEV1, get_fd, set_fd))
+	if (tc_prog_attach(IP6GENEVE_TUNL_DEV1, get_fd, set_fd))
 		goto done;
 
 	ping_dev0();
@@ -1083,7 +1004,7 @@ static void test_ip6tnl_tunnel(enum ip6tnl_test test)
 		get_fd = bpf_program__fd(skel->progs.ip6ip6_get_tunnel);
 		break;
 	}
-	if (generic_attach(IP6TNL_TUNL_DEV1, get_fd, set_fd))
+	if (tc_prog_attach(IP6TNL_TUNL_DEV1, get_fd, set_fd))
 		goto done;
 
 	ping6_veth0();

From dcfd494036d62fe849ef88b2d5023542f76afbcc Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Alexis=20Lothor=C3=A9=20=28eBPF=20Foundation=29?=
 <alexis.lothore@bootlin.com>
Date: Wed, 22 Oct 2025 09:39:51 +0200
Subject: [PATCH 2/4] selftests/bpf: make test_tc_tunnel.bpf.c compatible with
 big endian platforms
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

When trying to run bpf-based encapsulation in a s390x environment, some
parts of test_tc_tunnel.bpf.o do not encapsulate correctly the traffic,
leading to tests failures. Adding some logs shows for example that
packets about to be sent on an interface with the ip6vxlan_eth program
attached do not have the expected value 5 in the ip header ihl field,
and so are ignored by the program.

This phenomenon appears when trying to cross-compile the selftests,
rather than compiling it from a virtualized host: the selftests build
system may then wrongly pick some host headers. If <asm/byteorder.h>
ends up being picked on the host (and if the host has a endianness
different from the target one), it will then expose wrong endianness
defines (e.g __LITTLE_ENDIAN_BITFIELD instead of __BIT_ENDIAN_BITFIELD),
and it will for example mess up the iphdr structure layout used in the
ebpf program.

To prevent this, directly use the vmlinux.h header generated by the
selftests build system rather than including directly specific kernel
headers. As a consequence, add some missing definitions that are not
exposed by vmlinux.h, and adapt the bitfield manipulations to allow
building and using the program on both types of platforms.

Signed-off-by: Alexis Lothoré (eBPF Foundation) <alexis.lothore@bootlin.com>
---
 .../selftests/bpf/progs/test_tc_tunnel.c      | 57 +++++++------------
 1 file changed, 22 insertions(+), 35 deletions(-)

diff --git a/tools/testing/selftests/bpf/progs/test_tc_tunnel.c b/tools/testing/selftests/bpf/progs/test_tc_tunnel.c
index 404124a938927..b509e4c99648c 100644
--- a/tools/testing/selftests/bpf/progs/test_tc_tunnel.c
+++ b/tools/testing/selftests/bpf/progs/test_tc_tunnel.c
@@ -2,23 +2,11 @@
 
 /* In-place tunneling */
 
-#include <stdbool.h>
-#include <string.h>
-
-#include <linux/stddef.h>
-#include <linux/bpf.h>
-#include <linux/if_ether.h>
-#include <linux/in.h>
-#include <linux/ip.h>
-#include <linux/ipv6.h>
-#include <linux/mpls.h>
-#include <linux/tcp.h>
-#include <linux/udp.h>
-#include <linux/pkt_cls.h>
-#include <linux/types.h>
+#include <vmlinux.h>
 
-#include <bpf/bpf_endian.h>
 #include <bpf/bpf_helpers.h>
+#include <bpf/bpf_endian.h>
+#include "bpf_tracing_net.h"
 #include "bpf_compiler.h"
 
 #pragma GCC diagnostic ignored "-Waddress-of-packed-member"
@@ -27,6 +15,14 @@ static const int cfg_port = 8000;
 
 static const int cfg_udp_src = 20000;
 
+#define ETH_P_MPLS_UC	0x8847
+#define ETH_P_TEB	0x6558
+
+#define MPLS_LS_S_MASK	0x00000100
+#define BPF_F_ADJ_ROOM_ENCAP_L2(len)			\
+	(((__u64)len & BPF_ADJ_ROOM_ENCAP_L2_MASK)	\
+	 << BPF_ADJ_ROOM_ENCAP_L2_SHIFT)
+
 #define	L2_PAD_SZ	(sizeof(struct vxlanhdr) + ETH_HLEN)
 
 #define	UDP_PORT		5555
@@ -36,10 +32,9 @@ static const int cfg_udp_src = 20000;
 
 #define	EXTPROTO_VXLAN	0x1
 
-#define	VXLAN_N_VID     (1u << 24)
-#define	VXLAN_VNI_MASK	bpf_htonl((VXLAN_N_VID - 1) << 8)
-#define	VXLAN_FLAGS     0x8
-#define	VXLAN_VNI       1
+#define	VXLAN_FLAGS     bpf_htonl(1<<27)
+#define	VNI_ID		1
+#define	VXLAN_VNI	bpf_htonl(VNI_ID << 8)
 
 #ifndef NEXTHDR_DEST
 #define NEXTHDR_DEST	60
@@ -48,12 +43,6 @@ static const int cfg_udp_src = 20000;
 /* MPLS label 1000 with S bit (last label) set and ttl of 255. */
 static const __u32 mpls_label = __bpf_constant_htonl(1000 << 12 |
 						     MPLS_LS_S_MASK | 0xff);
-
-struct vxlanhdr {
-	__be32 vx_flags;
-	__be32 vx_vni;
-} __attribute__((packed));
-
 struct gre_hdr {
 	__be16 flags;
 	__be16 protocol;
@@ -94,8 +83,8 @@ static __always_inline void set_ipv4_csum(struct iphdr *iph)
 static __always_inline int __encap_ipv4(struct __sk_buff *skb, __u8 encap_proto,
 					__u16 l2_proto, __u16 ext_proto)
 {
+	struct iphdr iph_inner = {0};
 	__u16 udp_dst = UDP_PORT;
-	struct iphdr iph_inner;
 	struct v4hdr h_outer;
 	struct tcphdr tcph;
 	int olen, l2_len;
@@ -122,7 +111,6 @@ static __always_inline int __encap_ipv4(struct __sk_buff *skb, __u8 encap_proto,
 			return TC_ACT_OK;
 
 		/* Derive the IPv4 header fields from the IPv6 header */
-		memset(&iph_inner, 0, sizeof(iph_inner));
 		iph_inner.version = 4;
 		iph_inner.ihl = 5;
 		iph_inner.tot_len = bpf_htons(sizeof(iph6_inner) +
@@ -210,7 +198,7 @@ static __always_inline int __encap_ipv4(struct __sk_buff *skb, __u8 encap_proto,
 			struct vxlanhdr *vxlan_hdr = (struct vxlanhdr *)l2_hdr;
 
 			vxlan_hdr->vx_flags = VXLAN_FLAGS;
-			vxlan_hdr->vx_vni = bpf_htonl((VXLAN_VNI & VXLAN_VNI_MASK) << 8);
+			vxlan_hdr->vx_vni = VXLAN_VNI;
 
 			l2_hdr += sizeof(struct vxlanhdr);
 		}
@@ -340,7 +328,7 @@ static __always_inline int __encap_ipv6(struct __sk_buff *skb, __u8 encap_proto,
 			struct vxlanhdr *vxlan_hdr = (struct vxlanhdr *)l2_hdr;
 
 			vxlan_hdr->vx_flags = VXLAN_FLAGS;
-			vxlan_hdr->vx_vni = bpf_htonl((VXLAN_VNI & VXLAN_VNI_MASK) << 8);
+			vxlan_hdr->vx_vni = VXLAN_VNI;
 
 			l2_hdr += sizeof(struct vxlanhdr);
 		}
@@ -372,8 +360,8 @@ static __always_inline int __encap_ipv6(struct __sk_buff *skb, __u8 encap_proto,
 
 static int encap_ipv6_ipip6(struct __sk_buff *skb)
 {
+	struct v6hdr h_outer = {0};
 	struct iphdr iph_inner;
-	struct v6hdr h_outer;
 	struct tcphdr tcph;
 	struct ethhdr eth;
 	__u64 flags;
@@ -400,13 +388,12 @@ static int encap_ipv6_ipip6(struct __sk_buff *skb)
 		return TC_ACT_SHOT;
 
 	/* prepare new outer network header */
-	memset(&h_outer.ip, 0, sizeof(h_outer.ip));
 	h_outer.ip.version = 6;
 	h_outer.ip.hop_limit = iph_inner.ttl;
-	h_outer.ip.saddr.s6_addr[1] = 0xfd;
-	h_outer.ip.saddr.s6_addr[15] = 1;
-	h_outer.ip.daddr.s6_addr[1] = 0xfd;
-	h_outer.ip.daddr.s6_addr[15] = 2;
+	h_outer.ip.saddr.in6_u.u6_addr8[1] = 0xfd;
+	h_outer.ip.saddr.in6_u.u6_addr8[15] = 1;
+	h_outer.ip.daddr.in6_u.u6_addr8[1] = 0xfd;
+	h_outer.ip.daddr.in6_u.u6_addr8[15] = 2;
 	h_outer.ip.payload_len = iph_inner.tot_len;
 	h_outer.ip.nexthdr = IPPROTO_IPIP;
 

From 066ca3d7472ff964ec312d7f1ff0908006846425 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Alexis=20Lothor=C3=A9=20=28eBPF=20Foundation=29?=
 <alexis.lothore@bootlin.com>
Date: Wed, 22 Oct 2025 09:39:52 +0200
Subject: [PATCH 3/4] selftests/bpf: integrate test_tc_tunnel.sh tests into
 test_progs
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

The test_tc_tunnel.sh script checks that a large variety of tunneling
mechanisms handled by the kernel can be handled as well by eBPF
programs. While this test shares similarities with test_tunnel.c (which
is already integrated in test_progs), those are testing slightly
different things:
- test_tunnel.c creates a tunnel interface, and then get and set tunnel
  keys in packet metadata, from BPF programs.
- test_tc_tunnels.sh manually parses/crafts packets content

Bring the tests covered by test_tc_tunnel.sh into the test_progs
framework, by creating a dedicated test_tc_tunnel.sh. This new test
defines a "generic" runner which, for each test configuration:
- will configure the relevant veth pair, each of those isolated in a
  dedicated namespace
- will check that traffic will fail if there is only an encapsulating
  program attached to one veth egress
- will check that traffic succeed if we enable some decapsulation module
  on kernel side
- will check that traffic still succeeds if we replace the kernel
  decapsulation with some eBPF ingress decapsulation.

Example of the new test execution:

  # ./test_progs -a tc_tunnel
  #447/1   tc_tunnel/ipip_none:OK
  #447/2   tc_tunnel/ipip6_none:OK
  #447/3   tc_tunnel/ip6tnl_none:OK
  #447/4   tc_tunnel/sit_none:OK
  #447/5   tc_tunnel/vxlan_eth:OK
  #447/6   tc_tunnel/ip6vxlan_eth:OK
  #447/7   tc_tunnel/gre_none:OK
  #447/8   tc_tunnel/gre_eth:OK
  #447/9   tc_tunnel/gre_mpls:OK
  #447/10  tc_tunnel/ip6gre_none:OK
  #447/11  tc_tunnel/ip6gre_eth:OK
  #447/12  tc_tunnel/ip6gre_mpls:OK
  #447/13  tc_tunnel/udp_none:OK
  #447/14  tc_tunnel/udp_eth:OK
  #447/15  tc_tunnel/udp_mpls:OK
  #447/16  tc_tunnel/ip6udp_none:OK
  #447/17  tc_tunnel/ip6udp_eth:OK
  #447/18  tc_tunnel/ip6udp_mpls:OK
  #447     tc_tunnel:OK
  Summary: 1/18 PASSED, 0 SKIPPED, 0 FAILED

Signed-off-by: Alexis Lothoré (eBPF Foundation) <alexis.lothore@bootlin.com>
---
 .../selftests/bpf/prog_tests/test_tc_tunnel.c | 660 ++++++++++++++++++
 .../selftests/bpf/progs/test_tc_tunnel.c      |  38 +-
 2 files changed, 679 insertions(+), 19 deletions(-)
 create mode 100644 tools/testing/selftests/bpf/prog_tests/test_tc_tunnel.c

diff --git a/tools/testing/selftests/bpf/prog_tests/test_tc_tunnel.c b/tools/testing/selftests/bpf/prog_tests/test_tc_tunnel.c
new file mode 100644
index 0000000000000..bf60ffcfee856
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/test_tc_tunnel.c
@@ -0,0 +1,660 @@
+// SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
+
+/*
+ * End-to-end eBPF tunnel test suite
+ *   The file tests BPF network tunnels implementation. For each tunnel
+ *   type, the test validates that:
+ *   - basic communication can first be established between the two veths
+ *   - when adding a BPF-based encapsulation on client egress, it now fails
+ *   to communicate with the server
+ *   - when adding a kernel-based decapsulation on server ingress, client
+ *   can now connect
+ *   - when replacing the kernel-based decapsulation with a BPF-based one,
+ *   the client can still connect
+ */
+
+#include <stdio.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <sys/socket.h>
+#include <bpf/libbpf.h>
+
+#include "test_progs.h"
+#include "network_helpers.h"
+#include "test_tc_tunnel.skel.h"
+
+#define SERVER_NS	"tc-tunnel-server-ns"
+#define CLIENT_NS	"tc-tunnel-client-ns"
+#define MAC_ADDR_VETH1	"00:11:22:33:44:55"
+#define IP4_ADDR_VETH1	"192.168.1.1"
+#define IP6_ADDR_VETH1	"fd::1"
+#define MAC_ADDR_VETH2	"66:77:88:99:AA:BB"
+#define IP4_ADDR_VETH2	"192.168.1.2"
+#define IP6_ADDR_VETH2	"fd::2"
+
+#define TEST_NAME_MAX_LEN	64
+#define PROG_NAME_MAX_LEN	64
+#define TUNNEL_ARGS_MAX_LEN	128
+#define BUFFER_LEN		2000
+#define DEFAULT_TEST_DATA_SIZE	100
+#define GSO_TEST_DATA_SIZE	BUFFER_LEN
+
+#define TIMEOUT_MS			1000
+#define TEST_PORT			8000
+#define UDP_PORT			5555
+#define MPLS_UDP_PORT			6635
+#define FOU_MPLS_PROTO			137
+#define VXLAN_ID			1
+#define VXLAN_PORT			8472
+#define MPLS_TABLE_ENTRIES_COUNT	65536
+
+static char tx_buffer[BUFFER_LEN], rx_buffer[BUFFER_LEN];
+
+struct subtest_cfg {
+	char *ebpf_tun_type;
+	char *iproute_tun_type;
+	char *mac_tun_type;
+	int ipproto;
+	void (*extra_decap_mod_args_cb)(struct subtest_cfg *cfg, char *dst);
+	bool tunnel_need_veth_mac;
+	bool configure_fou_rx_port;
+	char *tmode;
+	bool expect_kern_decap_failure;
+	bool configure_mpls;
+	bool test_gso;
+	char *tunnel_client_addr;
+	char *tunnel_server_addr;
+	char name[TEST_NAME_MAX_LEN];
+	char *server_addr;
+	int client_egress_prog_fd;
+	int server_ingress_prog_fd;
+	char extra_decap_mod_args[TUNNEL_ARGS_MAX_LEN];
+	int *server_fd;
+};
+
+struct connection {
+	int client_fd;
+	int server_fd;
+};
+
+static int build_subtest_name(struct subtest_cfg *cfg, char *dst, size_t size)
+{
+	int ret;
+
+	ret = snprintf(dst, size, "%s_%s", cfg->ebpf_tun_type,
+		       cfg->mac_tun_type);
+
+	return ret < 0 ? ret : 0;
+}
+
+static int set_subtest_progs(struct subtest_cfg *cfg, struct test_tc_tunnel *skel)
+{
+	char prog_name[PROG_NAME_MAX_LEN];
+	struct bpf_program *prog;
+	int ret;
+
+	ret = snprintf(prog_name, PROG_NAME_MAX_LEN, "__encap_");
+	if (ret < 0)
+		return ret;
+	ret = build_subtest_name(cfg, prog_name + ret, PROG_NAME_MAX_LEN - ret);
+	if (ret < 0)
+		return ret;
+	prog = bpf_object__find_program_by_name(skel->obj, prog_name);
+	if (!prog)
+		return -1;
+
+	cfg->client_egress_prog_fd = bpf_program__fd(prog);
+	cfg->server_ingress_prog_fd = bpf_program__fd(skel->progs.decap_f);
+	return 0;
+}
+
+static void set_subtest_addresses(struct subtest_cfg *cfg)
+{
+	if (cfg->ipproto == 6)
+		cfg->server_addr = IP6_ADDR_VETH2;
+	else
+		cfg->server_addr = IP4_ADDR_VETH2;
+
+	/* Some specific tunnel types need specific addressing, it then
+	 * has been already set in the configuration table. Otherwise,
+	 * deduce the relevant addressing from the ipproto
+	 */
+	if (cfg->tunnel_client_addr && cfg->tunnel_server_addr)
+		return;
+
+	if (cfg->ipproto == 6) {
+		cfg->tunnel_client_addr = IP6_ADDR_VETH1;
+		cfg->tunnel_server_addr = IP6_ADDR_VETH2;
+	} else {
+		cfg->tunnel_client_addr = IP4_ADDR_VETH1;
+		cfg->tunnel_server_addr = IP4_ADDR_VETH2;
+	}
+}
+
+static int run_server(struct subtest_cfg *cfg)
+{
+	struct nstoken *nstoken = open_netns(SERVER_NS);
+	int family = cfg->ipproto == 6 ? AF_INET6 : AF_INET;
+
+	cfg->server_fd = start_reuseport_server(family, SOCK_STREAM,
+						cfg->server_addr, TEST_PORT,
+						TIMEOUT_MS, 1);
+	close_netns(nstoken);
+	if (!ASSERT_NEQ(cfg->server_fd, NULL, "start server"))
+		return -1;
+
+	return 0;
+}
+
+static void stop_server(struct subtest_cfg *cfg)
+{
+	close(*cfg->server_fd);
+	cfg->server_fd = NULL;
+}
+
+static int check_server_rx_data(struct subtest_cfg *cfg,
+				struct connection *conn, int len)
+{
+	int err;
+
+	memset(rx_buffer, 0, BUFFER_LEN);
+	err = recv(conn->server_fd, rx_buffer, len, 0);
+	if (!ASSERT_EQ(err, len, "check rx data len"))
+		return 1;
+	if (!ASSERT_MEMEQ(tx_buffer, rx_buffer, len, "check received data"))
+		return 1;
+	return 0;
+}
+
+static struct connection *connect_client_to_server(struct subtest_cfg *cfg)
+{
+	struct network_helper_opts opts = {.timeout_ms = 500};
+	int family = cfg->ipproto == 6 ? AF_INET6 : AF_INET;
+	struct connection *conn = NULL;
+	int client_fd, server_fd;
+
+	client_fd = connect_to_addr_str(family, SOCK_STREAM, cfg->server_addr,
+					TEST_PORT, &opts);
+
+	if (client_fd < 0)
+		return NULL;
+
+	server_fd = accept(*cfg->server_fd, NULL, NULL);
+	if (server_fd < 0)
+		return NULL;
+
+	conn = malloc(sizeof(struct connection));
+	if (conn) {
+		conn->server_fd = server_fd;
+		conn->client_fd = client_fd;
+	}
+
+	return conn;
+}
+
+static void disconnect_client_from_server(struct subtest_cfg *cfg,
+					  struct connection *conn)
+{
+	close(conn->server_fd);
+	close(conn->client_fd);
+	free(conn);
+}
+
+static int send_and_test_data(struct subtest_cfg *cfg, bool must_succeed)
+{
+	struct connection *conn;
+	int err, res = -1;
+
+	conn = connect_client_to_server(cfg);
+	if (!must_succeed && !ASSERT_EQ(conn, NULL, "connection that must fail"))
+		goto end;
+	else if (!must_succeed)
+		return 0;
+
+	if (!ASSERT_NEQ(conn, NULL, "connection that must succeed"))
+		return 1;
+
+	err = send(conn->client_fd, tx_buffer, DEFAULT_TEST_DATA_SIZE, 0);
+	if (!ASSERT_EQ(err, DEFAULT_TEST_DATA_SIZE, "send data from client"))
+		goto end;
+	if (check_server_rx_data(cfg, conn, DEFAULT_TEST_DATA_SIZE))
+		goto end;
+
+	if (!cfg->test_gso) {
+		res = 0;
+		goto end;
+	}
+
+	err = send(conn->client_fd, tx_buffer, GSO_TEST_DATA_SIZE, 0);
+	if (!ASSERT_EQ(err, GSO_TEST_DATA_SIZE, "send (large) data from client"))
+		goto end;
+	if (check_server_rx_data(cfg, conn, DEFAULT_TEST_DATA_SIZE))
+		goto end;
+
+	res = 0;
+end:
+	disconnect_client_from_server(cfg, conn);
+	return res;
+}
+
+static void vxlan_decap_mod_args_cb(struct subtest_cfg *cfg, char *dst)
+{
+	snprintf(dst, TUNNEL_ARGS_MAX_LEN, "id %d dstport %d udp6zerocsumrx",
+		 VXLAN_ID, VXLAN_PORT);
+}
+
+static void udp_decap_mod_args_cb(struct subtest_cfg *cfg, char *dst)
+{
+	bool is_mpls = !strcmp(cfg->mac_tun_type, "mpls");
+
+	snprintf(dst, TUNNEL_ARGS_MAX_LEN,
+		 "encap fou encap-sport auto encap-dport %d",
+		 is_mpls ? MPLS_UDP_PORT : UDP_PORT);
+}
+
+static int configure_fou_rx_port(struct subtest_cfg *cfg, bool add)
+{
+	bool is_mpls = strcmp(cfg->mac_tun_type, "mpls") == 0;
+	int fou_proto;
+
+	if (is_mpls)
+		fou_proto = FOU_MPLS_PROTO;
+	else
+		fou_proto = cfg->ipproto == 6 ? 41 : 4;
+
+	SYS(fail, "ip fou %s port %d ipproto %d%s", add ? "add" : "del",
+	    is_mpls ? MPLS_UDP_PORT : UDP_PORT, fou_proto,
+	    cfg->ipproto == 6 ? " -6" : "");
+
+	return 0;
+fail:
+	return 1;
+}
+
+static int add_fou_rx_port(struct subtest_cfg *cfg)
+{
+	return configure_fou_rx_port(cfg, true);
+}
+
+static int del_fou_rx_port(struct subtest_cfg *cfg)
+{
+	return configure_fou_rx_port(cfg, false);
+}
+
+static int update_tunnel_intf_addr(struct subtest_cfg *cfg)
+{
+	SYS(fail, "ip link set dev testtun0 address " MAC_ADDR_VETH2);
+	return 0;
+fail:
+	return -1;
+}
+
+static int configure_kernel_for_mpls(struct subtest_cfg *cfg)
+{
+	SYS(fail, "sysctl -qw net.mpls.platform_labels=%d",
+	    MPLS_TABLE_ENTRIES_COUNT);
+	SYS(fail, "ip -f mpls route add 1000 dev lo");
+	SYS(fail, "ip link set lo up");
+	SYS(fail, "sysctl -qw net.mpls.conf.testtun0.input=1");
+	SYS(fail, "sysctl -qw net.ipv4.conf.lo.rp_filter=0");
+	return 0;
+fail:
+	return -1;
+}
+
+static int configure_encapsulation(struct subtest_cfg *cfg)
+{
+	int ret;
+
+	ret = tc_prog_attach("veth1", -1, cfg->client_egress_prog_fd);
+
+	return ret;
+}
+
+static int configure_kernel_decapsulation(struct subtest_cfg *cfg)
+{
+	struct nstoken *nstoken = open_netns(SERVER_NS);
+
+	if (cfg->configure_fou_rx_port &&
+	    !ASSERT_OK(add_fou_rx_port(cfg), "configure FOU RX port"))
+		goto fail;
+	SYS(fail, "ip link add name testtun0 type %s %s remote %s local %s %s",
+	    cfg->iproute_tun_type, cfg->tmode ? cfg->tmode : "",
+	    cfg->tunnel_client_addr, cfg->tunnel_server_addr,
+	    cfg->extra_decap_mod_args);
+	if (cfg->tunnel_need_veth_mac &&
+	    !ASSERT_OK(update_tunnel_intf_addr(cfg), "update testtun0 mac"))
+		goto fail;
+	if (cfg->configure_mpls &&
+	    (!ASSERT_OK(configure_kernel_for_mpls(cfg),
+			"configure MPLS decap")))
+		goto fail;
+	SYS(fail, "sysctl -qw net.ipv4.conf.all.rp_filter=0");
+	SYS(fail, "sysctl -qw net.ipv4.conf.testtun0.rp_filter=0");
+	SYS(fail, "ip link set dev testtun0 up");
+	close_netns(nstoken);
+	return 0;
+fail:
+	close_netns(nstoken);
+	return -1;
+}
+
+static int configure_ebpf_decapsulation(struct subtest_cfg *cfg)
+{
+	struct nstoken *nstoken = open_netns(SERVER_NS);
+
+	SYS(fail, "ip link del testtun0");
+	if (!ASSERT_OK(tc_prog_attach("veth2", cfg->server_ingress_prog_fd, -1),
+		       "attach_program"))
+		goto fail;
+	close_netns(nstoken);
+	return 0;
+fail:
+	close_netns(nstoken);
+	return -1;
+}
+
+static void run_test(struct subtest_cfg *cfg)
+{
+	struct nstoken *nstoken = open_netns(CLIENT_NS);
+
+	if (!ASSERT_OK(run_server(cfg), "run server"))
+		goto fail;
+
+	/* Basic communication must work */
+	if (!ASSERT_OK(send_and_test_data(cfg, true), "connect without any encap"))
+		goto fail;
+
+	/* Attach encapsulation program to client, communication must fail */
+	if (!ASSERT_OK(configure_encapsulation(cfg), "configure encapsulation"))
+		return;
+	if (!ASSERT_OK(send_and_test_data(cfg, false), "connect with encap prog only"))
+		goto fail;
+
+	/* Insert kernel decap module, connection must succeed */
+	if (!ASSERT_OK(configure_kernel_decapsulation(cfg), "configure kernel decapsulation"))
+		goto fail;
+	if (!ASSERT_OK(send_and_test_data(cfg, !cfg->expect_kern_decap_failure),
+		       "connect with encap prog and kern decap"))
+		goto fail;
+
+	/* Replace kernel module with BPF decap, test must pass */
+	if (!ASSERT_OK(configure_ebpf_decapsulation(cfg), "configure ebpf decapsulation"))
+		goto fail;
+	ASSERT_OK(send_and_test_data(cfg, true), "connect with encap and decap progs");
+
+fail:
+	stop_server(cfg);
+	close_netns(nstoken);
+}
+
+static int setup(void)
+{
+	struct nstoken *nstoken = NULL;
+	int fd, err;
+
+	fd = open("/dev/urandom", O_RDONLY);
+	if (!ASSERT_OK_FD(fd, "open urandom"))
+		goto fail;
+	err = read(fd, tx_buffer, BUFFER_LEN);
+	close(fd);
+
+	if (!ASSERT_EQ(err, BUFFER_LEN, "read random bytes"))
+		goto fail;
+
+	/* Configure the testing network */
+	if (!ASSERT_OK(make_netns(CLIENT_NS), "create client ns") ||
+	    !ASSERT_OK(make_netns(SERVER_NS), "create server ns"))
+		goto fail;
+
+	nstoken = open_netns(CLIENT_NS);
+	SYS(fail, "ip link add %s type veth peer name %s",
+	    "veth1 mtu 1500 netns " CLIENT_NS " address " MAC_ADDR_VETH1,
+	    "veth2 mtu 1500 netns " SERVER_NS " address " MAC_ADDR_VETH2);
+	SYS(fail, "ethtool -K veth1 tso off");
+	SYS(fail, "ip link set veth1 up");
+	close_netns(nstoken);
+	nstoken = open_netns(SERVER_NS);
+	SYS(fail, "ip link set veth2 up");
+	close_netns(nstoken);
+
+	return 0;
+fail:
+	close_netns(nstoken);
+	return 1;
+}
+
+static int subtest_setup(struct test_tc_tunnel *skel, struct subtest_cfg *cfg)
+{
+	struct nstoken *nstoken;
+
+	set_subtest_addresses(cfg);
+	if (!ASSERT_OK(set_subtest_progs(cfg, skel),
+		       "find subtest progs"))
+		return -1;
+	if (cfg->extra_decap_mod_args_cb)
+		cfg->extra_decap_mod_args_cb(cfg, cfg->extra_decap_mod_args);
+
+	nstoken = open_netns(CLIENT_NS);
+	SYS(fail, "ip -4 addr add " IP4_ADDR_VETH1 "/24 dev veth1");
+	SYS(fail, "ip -4 route flush table main");
+	SYS(fail, "ip -4 route add " IP4_ADDR_VETH2 " mtu 1450 dev veth1");
+	SYS(fail, "ip -6 addr add " IP6_ADDR_VETH1 "/64 dev veth1 nodad");
+	SYS(fail, "ip -6 route flush table main");
+	SYS(fail, "ip -6 route add " IP6_ADDR_VETH2 " mtu 1430 dev veth1");
+	close_netns(nstoken);
+
+	nstoken = open_netns(SERVER_NS);
+	SYS(fail, "ip -4 addr add " IP4_ADDR_VETH2 "/24 dev veth2");
+	SYS(fail, "ip -6 addr add " IP6_ADDR_VETH2 "/64 dev veth2 nodad");
+	close_netns(nstoken);
+
+	return 0;
+fail:
+	close_netns(nstoken);
+	return -1;
+}
+
+static void subtest_cleanup(struct subtest_cfg *cfg)
+{
+	struct nstoken *nstoken;
+
+	nstoken = open_netns(CLIENT_NS);
+	SYS_NOFAIL("tc qdisc delete dev veth1 parent ffff:fff1");
+	SYS_NOFAIL("ip a flush veth1");
+	close_netns(nstoken);
+	nstoken = open_netns(SERVER_NS);
+	SYS_NOFAIL("ip link del testtun0");
+	SYS_NOFAIL("tc qdisc delete dev veth2 parent ffff:fff1");
+	SYS_NOFAIL("ip a flush veth2");
+	if (cfg->configure_mpls)
+		SYS_NOFAIL("ip -f mpls route del 1000 dev lo");
+	if (cfg->configure_fou_rx_port)
+		del_fou_rx_port(cfg);
+
+	close_netns(nstoken);
+}
+
+static void cleanup(void)
+{
+	remove_netns(CLIENT_NS);
+	remove_netns(SERVER_NS);
+}
+
+static struct subtest_cfg subtests_cfg[] = {
+	{
+		.ebpf_tun_type = "ipip",
+		.mac_tun_type = "none",
+		.iproute_tun_type = "ipip",
+		.ipproto = 4,
+	},
+	{
+		.ebpf_tun_type = "ipip6",
+		.mac_tun_type = "none",
+		.iproute_tun_type = "ip6tnl",
+		.ipproto = 4,
+		.tunnel_client_addr = IP6_ADDR_VETH1,
+		.tunnel_server_addr = IP6_ADDR_VETH2,
+	},
+	{
+		.ebpf_tun_type = "ip6tnl",
+		.iproute_tun_type = "ip6tnl",
+		.mac_tun_type = "none",
+		.ipproto = 6,
+	},
+	{
+		.mac_tun_type = "none",
+		.ebpf_tun_type = "sit",
+		.iproute_tun_type = "sit",
+		.ipproto = 6,
+		.tunnel_client_addr = IP4_ADDR_VETH1,
+		.tunnel_server_addr = IP4_ADDR_VETH2,
+	},
+	{
+		.ebpf_tun_type = "vxlan",
+		.mac_tun_type = "eth",
+		.iproute_tun_type = "vxlan",
+		.ipproto = 4,
+		.extra_decap_mod_args_cb = vxlan_decap_mod_args_cb,
+		.tunnel_need_veth_mac = true
+	},
+	{
+		.ebpf_tun_type = "ip6vxlan",
+		.mac_tun_type = "eth",
+		.iproute_tun_type = "vxlan",
+		.ipproto = 6,
+		.extra_decap_mod_args_cb = vxlan_decap_mod_args_cb,
+		.tunnel_need_veth_mac = true
+	},
+	{
+		.ebpf_tun_type = "gre",
+		.mac_tun_type = "none",
+		.iproute_tun_type = "gre",
+		.ipproto = 4,
+		.test_gso = true
+	},
+	{
+		.ebpf_tun_type = "gre",
+		.mac_tun_type = "eth",
+		.iproute_tun_type = "gretap",
+		.ipproto = 4,
+		.tunnel_need_veth_mac = true,
+		.test_gso = true
+	},
+	{
+		.ebpf_tun_type = "gre",
+		.mac_tun_type = "mpls",
+		.iproute_tun_type = "gre",
+		.ipproto = 4,
+		.configure_mpls = true,
+		.test_gso = true
+	},
+	{
+		.ebpf_tun_type = "ip6gre",
+		.mac_tun_type = "none",
+		.iproute_tun_type = "ip6gre",
+		.ipproto = 6,
+		.test_gso = true,
+	},
+	{
+		.ebpf_tun_type = "ip6gre",
+		.mac_tun_type = "eth",
+		.iproute_tun_type = "ip6gretap",
+		.ipproto = 6,
+		.tunnel_need_veth_mac = true,
+		.test_gso = true
+	},
+	{
+		.ebpf_tun_type = "ip6gre",
+		.mac_tun_type = "mpls",
+		.iproute_tun_type = "ip6gre",
+		.ipproto = 6,
+		.configure_mpls = true,
+		.test_gso = true
+	},
+	{
+		.ebpf_tun_type = "udp",
+		.mac_tun_type = "none",
+		.iproute_tun_type = "ipip",
+		.ipproto = 4,
+		.extra_decap_mod_args_cb = udp_decap_mod_args_cb,
+		.configure_fou_rx_port = true,
+		.test_gso = true
+	},
+	{
+		.ebpf_tun_type = "udp",
+		.mac_tun_type = "eth",
+		.iproute_tun_type = "ipip",
+		.ipproto = 4,
+		.extra_decap_mod_args_cb = udp_decap_mod_args_cb,
+		.configure_fou_rx_port = true,
+		.expect_kern_decap_failure = true,
+		.test_gso = true
+	},
+	{
+		.ebpf_tun_type = "udp",
+		.mac_tun_type = "mpls",
+		.iproute_tun_type = "ipip",
+		.ipproto = 4,
+		.extra_decap_mod_args_cb = udp_decap_mod_args_cb,
+		.configure_fou_rx_port = true,
+		.tmode = "mode any ttl 255",
+		.configure_mpls = true,
+		.test_gso = true
+	},
+	{
+		.ebpf_tun_type = "ip6udp",
+		.mac_tun_type = "none",
+		.iproute_tun_type = "ip6tnl",
+		.ipproto = 6,
+		.extra_decap_mod_args_cb = udp_decap_mod_args_cb,
+		.configure_fou_rx_port = true,
+		.test_gso = true
+	},
+	{
+		.ebpf_tun_type = "ip6udp",
+		.mac_tun_type = "eth",
+		.iproute_tun_type = "ip6tnl",
+		.ipproto = 6,
+		.extra_decap_mod_args_cb = udp_decap_mod_args_cb,
+		.configure_fou_rx_port = true,
+		.expect_kern_decap_failure = true,
+		.test_gso = true
+	},
+	{
+		.ebpf_tun_type = "ip6udp",
+		.mac_tun_type = "mpls",
+		.iproute_tun_type = "ip6tnl",
+		.ipproto = 6,
+		.extra_decap_mod_args_cb = udp_decap_mod_args_cb,
+		.configure_fou_rx_port = true,
+		.tmode = "mode any ttl 255",
+		.expect_kern_decap_failure = true,
+		.test_gso = true
+	},
+};
+
+void test_tc_tunnel(void)
+{
+	struct test_tc_tunnel *skel;
+	struct subtest_cfg *cfg;
+	int i, ret;
+
+	skel = test_tc_tunnel__open_and_load();
+	if (!ASSERT_OK_PTR(skel, "skel open and load"))
+		return;
+
+	if (!ASSERT_OK(setup(), "global setup"))
+		return;
+
+	for (i = 0; i < ARRAY_SIZE(subtests_cfg); i++) {
+		cfg = &subtests_cfg[i];
+		ret = build_subtest_name(cfg, cfg->name, TEST_NAME_MAX_LEN);
+		if (ret < 0 || !test__start_subtest(cfg->name))
+			continue;
+		subtest_setup(skel, cfg);
+		run_test(cfg);
+		subtest_cleanup(cfg);
+	}
+	cleanup();
+}
diff --git a/tools/testing/selftests/bpf/progs/test_tc_tunnel.c b/tools/testing/selftests/bpf/progs/test_tc_tunnel.c
index b509e4c99648c..7330c61b5730c 100644
--- a/tools/testing/selftests/bpf/progs/test_tc_tunnel.c
+++ b/tools/testing/selftests/bpf/progs/test_tc_tunnel.c
@@ -418,7 +418,7 @@ static __always_inline int encap_ipv6(struct __sk_buff *skb, __u8 encap_proto,
 	return __encap_ipv6(skb, encap_proto, l2_proto, 0);
 }
 
-SEC("encap_ipip_none")
+SEC("tc")
 int __encap_ipip_none(struct __sk_buff *skb)
 {
 	if (skb->protocol == __bpf_constant_htons(ETH_P_IP))
@@ -427,7 +427,7 @@ int __encap_ipip_none(struct __sk_buff *skb)
 		return TC_ACT_OK;
 }
 
-SEC("encap_gre_none")
+SEC("tc")
 int __encap_gre_none(struct __sk_buff *skb)
 {
 	if (skb->protocol == __bpf_constant_htons(ETH_P_IP))
@@ -436,7 +436,7 @@ int __encap_gre_none(struct __sk_buff *skb)
 		return TC_ACT_OK;
 }
 
-SEC("encap_gre_mpls")
+SEC("tc")
 int __encap_gre_mpls(struct __sk_buff *skb)
 {
 	if (skb->protocol == __bpf_constant_htons(ETH_P_IP))
@@ -445,7 +445,7 @@ int __encap_gre_mpls(struct __sk_buff *skb)
 		return TC_ACT_OK;
 }
 
-SEC("encap_gre_eth")
+SEC("tc")
 int __encap_gre_eth(struct __sk_buff *skb)
 {
 	if (skb->protocol == __bpf_constant_htons(ETH_P_IP))
@@ -454,7 +454,7 @@ int __encap_gre_eth(struct __sk_buff *skb)
 		return TC_ACT_OK;
 }
 
-SEC("encap_udp_none")
+SEC("tc")
 int __encap_udp_none(struct __sk_buff *skb)
 {
 	if (skb->protocol == __bpf_constant_htons(ETH_P_IP))
@@ -463,7 +463,7 @@ int __encap_udp_none(struct __sk_buff *skb)
 		return TC_ACT_OK;
 }
 
-SEC("encap_udp_mpls")
+SEC("tc")
 int __encap_udp_mpls(struct __sk_buff *skb)
 {
 	if (skb->protocol == __bpf_constant_htons(ETH_P_IP))
@@ -472,7 +472,7 @@ int __encap_udp_mpls(struct __sk_buff *skb)
 		return TC_ACT_OK;
 }
 
-SEC("encap_udp_eth")
+SEC("tc")
 int __encap_udp_eth(struct __sk_buff *skb)
 {
 	if (skb->protocol == __bpf_constant_htons(ETH_P_IP))
@@ -481,7 +481,7 @@ int __encap_udp_eth(struct __sk_buff *skb)
 		return TC_ACT_OK;
 }
 
-SEC("encap_vxlan_eth")
+SEC("tc")
 int __encap_vxlan_eth(struct __sk_buff *skb)
 {
 	if (skb->protocol == __bpf_constant_htons(ETH_P_IP))
@@ -492,7 +492,7 @@ int __encap_vxlan_eth(struct __sk_buff *skb)
 		return TC_ACT_OK;
 }
 
-SEC("encap_sit_none")
+SEC("tc")
 int __encap_sit_none(struct __sk_buff *skb)
 {
 	if (skb->protocol == __bpf_constant_htons(ETH_P_IPV6))
@@ -501,7 +501,7 @@ int __encap_sit_none(struct __sk_buff *skb)
 		return TC_ACT_OK;
 }
 
-SEC("encap_ip6tnl_none")
+SEC("tc")
 int __encap_ip6tnl_none(struct __sk_buff *skb)
 {
 	if (skb->protocol == __bpf_constant_htons(ETH_P_IPV6))
@@ -510,7 +510,7 @@ int __encap_ip6tnl_none(struct __sk_buff *skb)
 		return TC_ACT_OK;
 }
 
-SEC("encap_ipip6_none")
+SEC("tc")
 int __encap_ipip6_none(struct __sk_buff *skb)
 {
 	if (skb->protocol == __bpf_constant_htons(ETH_P_IP))
@@ -519,7 +519,7 @@ int __encap_ipip6_none(struct __sk_buff *skb)
 		return TC_ACT_OK;
 }
 
-SEC("encap_ip6gre_none")
+SEC("tc")
 int __encap_ip6gre_none(struct __sk_buff *skb)
 {
 	if (skb->protocol == __bpf_constant_htons(ETH_P_IPV6))
@@ -528,7 +528,7 @@ int __encap_ip6gre_none(struct __sk_buff *skb)
 		return TC_ACT_OK;
 }
 
-SEC("encap_ip6gre_mpls")
+SEC("tc")
 int __encap_ip6gre_mpls(struct __sk_buff *skb)
 {
 	if (skb->protocol == __bpf_constant_htons(ETH_P_IPV6))
@@ -537,7 +537,7 @@ int __encap_ip6gre_mpls(struct __sk_buff *skb)
 		return TC_ACT_OK;
 }
 
-SEC("encap_ip6gre_eth")
+SEC("tc")
 int __encap_ip6gre_eth(struct __sk_buff *skb)
 {
 	if (skb->protocol == __bpf_constant_htons(ETH_P_IPV6))
@@ -546,7 +546,7 @@ int __encap_ip6gre_eth(struct __sk_buff *skb)
 		return TC_ACT_OK;
 }
 
-SEC("encap_ip6udp_none")
+SEC("tc")
 int __encap_ip6udp_none(struct __sk_buff *skb)
 {
 	if (skb->protocol == __bpf_constant_htons(ETH_P_IPV6))
@@ -555,7 +555,7 @@ int __encap_ip6udp_none(struct __sk_buff *skb)
 		return TC_ACT_OK;
 }
 
-SEC("encap_ip6udp_mpls")
+SEC("tc")
 int __encap_ip6udp_mpls(struct __sk_buff *skb)
 {
 	if (skb->protocol == __bpf_constant_htons(ETH_P_IPV6))
@@ -564,7 +564,7 @@ int __encap_ip6udp_mpls(struct __sk_buff *skb)
 		return TC_ACT_OK;
 }
 
-SEC("encap_ip6udp_eth")
+SEC("tc")
 int __encap_ip6udp_eth(struct __sk_buff *skb)
 {
 	if (skb->protocol == __bpf_constant_htons(ETH_P_IPV6))
@@ -573,7 +573,7 @@ int __encap_ip6udp_eth(struct __sk_buff *skb)
 		return TC_ACT_OK;
 }
 
-SEC("encap_ip6vxlan_eth")
+SEC("tc")
 int __encap_ip6vxlan_eth(struct __sk_buff *skb)
 {
 	if (skb->protocol == __bpf_constant_htons(ETH_P_IPV6))
@@ -680,7 +680,7 @@ static int decap_ipv6(struct __sk_buff *skb)
 			      iph_outer.nexthdr);
 }
 
-SEC("decap")
+SEC("tc")
 int decap_f(struct __sk_buff *skb)
 {
 	switch (skb->protocol) {

From 94a7d3258ca07172649b6915ea5219fa2c5eb649 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Alexis=20Lothor=C3=A9=20=28eBPF=20Foundation=29?=
 <alexis.lothore@bootlin.com>
Date: Wed, 22 Oct 2025 09:39:53 +0200
Subject: [PATCH 4/4] selftests/bpf: remove test_tc_tunnel.sh
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Now that test_tc_tunnel.sh scope has been ported to the test_progs
framework, remove it.

Signed-off-by: Alexis Lothoré (eBPF Foundation) <alexis.lothore@bootlin.com>
---
 tools/testing/selftests/bpf/Makefile          |   1 -
 tools/testing/selftests/bpf/test_tc_tunnel.sh | 320 ------------------
 2 files changed, 321 deletions(-)
 delete mode 100755 tools/testing/selftests/bpf/test_tc_tunnel.sh

diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile
index 7437c325179e4..bed43fd3d5d74 100644
--- a/tools/testing/selftests/bpf/Makefile
+++ b/tools/testing/selftests/bpf/Makefile
@@ -105,7 +105,6 @@ TEST_FILES = xsk_prereqs.sh $(wildcard progs/btf_dump_test_case_*.c)
 # Order correspond to 'make run_tests' order
 TEST_PROGS := test_kmod.sh \
 	test_lirc_mode2.sh \
-	test_tc_tunnel.sh \
 	test_tc_edt.sh \
 	test_xdping.sh \
 	test_bpftool_build.sh \
diff --git a/tools/testing/selftests/bpf/test_tc_tunnel.sh b/tools/testing/selftests/bpf/test_tc_tunnel.sh
deleted file mode 100755
index cb55a908bb0d7..0000000000000
--- a/tools/testing/selftests/bpf/test_tc_tunnel.sh
+++ /dev/null
@@ -1,320 +0,0 @@
-#!/bin/bash
-# SPDX-License-Identifier: GPL-2.0
-#
-# In-place tunneling
-
-BPF_FILE="test_tc_tunnel.bpf.o"
-# must match the port that the bpf program filters on
-readonly port=8000
-
-readonly ns_prefix="ns-$$-"
-readonly ns1="${ns_prefix}1"
-readonly ns2="${ns_prefix}2"
-
-readonly ns1_v4=192.168.1.1
-readonly ns2_v4=192.168.1.2
-readonly ns1_v6=fd::1
-readonly ns2_v6=fd::2
-
-# Must match port used by bpf program
-readonly udpport=5555
-# MPLSoverUDP
-readonly mplsudpport=6635
-readonly mplsproto=137
-
-readonly infile="$(mktemp)"
-readonly outfile="$(mktemp)"
-
-setup() {
-	ip netns add "${ns1}"
-	ip netns add "${ns2}"
-
-	ip link add dev veth1 mtu 1500 netns "${ns1}" type veth \
-	      peer name veth2 mtu 1500 netns "${ns2}"
-
-	ip netns exec "${ns1}" ethtool -K veth1 tso off
-
-	ip -netns "${ns1}" link set veth1 up
-	ip -netns "${ns2}" link set veth2 up
-
-	ip -netns "${ns1}" -4 addr add "${ns1_v4}/24" dev veth1
-	ip -netns "${ns2}" -4 addr add "${ns2_v4}/24" dev veth2
-	ip -netns "${ns1}" -6 addr add "${ns1_v6}/64" dev veth1 nodad
-	ip -netns "${ns2}" -6 addr add "${ns2_v6}/64" dev veth2 nodad
-
-	# clamp route to reserve room for tunnel headers
-	ip -netns "${ns1}" -4 route flush table main
-	ip -netns "${ns1}" -6 route flush table main
-	ip -netns "${ns1}" -4 route add "${ns2_v4}" mtu 1450 dev veth1
-	ip -netns "${ns1}" -6 route add "${ns2_v6}" mtu 1430 dev veth1
-
-	sleep 1
-
-	dd if=/dev/urandom of="${infile}" bs="${datalen}" count=1 status=none
-}
-
-cleanup() {
-	ip netns del "${ns2}"
-	ip netns del "${ns1}"
-
-	if [[ -f "${outfile}" ]]; then
-		rm "${outfile}"
-	fi
-	if [[ -f "${infile}" ]]; then
-		rm "${infile}"
-	fi
-
-	if [[ -n $server_pid ]]; then
-		kill $server_pid 2> /dev/null
-	fi
-}
-
-server_listen() {
-	ip netns exec "${ns2}" nc "${netcat_opt}" -l "${port}" > "${outfile}" &
-	server_pid=$!
-}
-
-client_connect() {
-	ip netns exec "${ns1}" timeout 2 nc "${netcat_opt}" -w 1 "${addr2}" "${port}" < "${infile}"
-	echo $?
-}
-
-verify_data() {
-	wait "${server_pid}"
-	server_pid=
-	# sha1sum returns two fields [sha1] [filepath]
-	# convert to bash array and access first elem
-	insum=($(sha1sum ${infile}))
-	outsum=($(sha1sum ${outfile}))
-	if [[ "${insum[0]}" != "${outsum[0]}" ]]; then
-		echo "data mismatch"
-		exit 1
-	fi
-}
-
-wait_for_port() {
-	for i in $(seq 20); do
-		if ip netns exec "${ns2}" ss ${2:--4}OHntl | grep -q "$1"; then
-			return 0
-		fi
-		sleep 0.1
-	done
-	return 1
-}
-
-set -e
-
-# no arguments: automated test, run all
-if [[ "$#" -eq "0" ]]; then
-	echo "ipip"
-	$0 ipv4 ipip none 100
-
-	echo "ipip6"
-	$0 ipv4 ipip6 none 100
-
-	echo "ip6ip6"
-	$0 ipv6 ip6tnl none 100
-
-	echo "sit"
-	$0 ipv6 sit none 100
-
-	echo "ip4 vxlan"
-	$0 ipv4 vxlan eth 2000
-
-	echo "ip6 vxlan"
-	$0 ipv6 ip6vxlan eth 2000
-
-	for mac in none mpls eth ; do
-		echo "ip gre $mac"
-		$0 ipv4 gre $mac 100
-
-		echo "ip6 gre $mac"
-		$0 ipv6 ip6gre $mac 100
-
-		echo "ip gre $mac gso"
-		$0 ipv4 gre $mac 2000
-
-		echo "ip6 gre $mac gso"
-		$0 ipv6 ip6gre $mac 2000
-
-		echo "ip udp $mac"
-		$0 ipv4 udp $mac 100
-
-		echo "ip6 udp $mac"
-		$0 ipv6 ip6udp $mac 100
-
-		echo "ip udp $mac gso"
-		$0 ipv4 udp $mac 2000
-
-		echo "ip6 udp $mac gso"
-		$0 ipv6 ip6udp $mac 2000
-	done
-
-	echo "OK. All tests passed"
-	exit 0
-fi
-
-if [[ "$#" -ne "4" ]]; then
-	echo "Usage: $0"
-	echo "   or: $0 <ipv4|ipv6> <tuntype> <none|mpls|eth> <data_len>"
-	exit 1
-fi
-
-case "$1" in
-"ipv4")
-	readonly addr1="${ns1_v4}"
-	readonly addr2="${ns2_v4}"
-	readonly ipproto=4
-	readonly netcat_opt=-${ipproto}
-	readonly foumod=fou
-	readonly foutype=ipip
-	readonly fouproto=4
-	readonly fouproto_mpls=${mplsproto}
-	readonly gretaptype=gretap
-	;;
-"ipv6")
-	readonly addr1="${ns1_v6}"
-	readonly addr2="${ns2_v6}"
-	readonly ipproto=6
-	readonly netcat_opt=-${ipproto}
-	readonly foumod=fou6
-	readonly foutype=ip6tnl
-	readonly fouproto="41 -6"
-	readonly fouproto_mpls="${mplsproto} -6"
-	readonly gretaptype=ip6gretap
-	;;
-*)
-	echo "unknown arg: $1"
-	exit 1
-	;;
-esac
-
-readonly tuntype=$2
-readonly mac=$3
-readonly datalen=$4
-
-echo "encap ${addr1} to ${addr2}, type ${tuntype}, mac ${mac} len ${datalen}"
-
-trap cleanup EXIT
-
-setup
-
-# basic communication works
-echo "test basic connectivity"
-server_listen
-wait_for_port ${port} ${netcat_opt}
-client_connect
-verify_data
-
-# clientside, insert bpf program to encap all TCP to port ${port}
-# client can no longer connect
-ip netns exec "${ns1}" tc qdisc add dev veth1 clsact
-ip netns exec "${ns1}" tc filter add dev veth1 egress \
-	bpf direct-action object-file ${BPF_FILE} \
-	section "encap_${tuntype}_${mac}"
-echo "test bpf encap without decap (expect failure)"
-server_listen
-wait_for_port ${port} ${netcat_opt}
-! client_connect
-
-if [[ "$tuntype" =~ "udp" ]]; then
-	# Set up fou tunnel.
-	ttype="${foutype}"
-	targs="encap fou encap-sport auto encap-dport $udpport"
-	# fou may be a module; allow this to fail.
-	modprobe "${foumod}" ||true
-	if [[ "$mac" == "mpls" ]]; then
-		dport=${mplsudpport}
-		dproto=${fouproto_mpls}
-		tmode="mode any ttl 255"
-	else
-		dport=${udpport}
-		dproto=${fouproto}
-	fi
-	ip netns exec "${ns2}" ip fou add port $dport ipproto ${dproto}
-	targs="encap fou encap-sport auto encap-dport $dport"
-elif [[ "$tuntype" =~ "gre" && "$mac" == "eth" ]]; then
-	ttype=$gretaptype
-elif [[ "$tuntype" =~ "vxlan" && "$mac" == "eth" ]]; then
-	ttype="vxlan"
-	targs="id 1 dstport 8472 udp6zerocsumrx"
-elif [[ "$tuntype" == "ipip6" ]]; then
-	ttype="ip6tnl"
-	targs=""
-else
-	ttype=$tuntype
-	targs=""
-fi
-
-# tunnel address family differs from inner for SIT
-if [[ "${tuntype}" == "sit" ]]; then
-	link_addr1="${ns1_v4}"
-	link_addr2="${ns2_v4}"
-elif [[ "${tuntype}" == "ipip6" ]]; then
-	link_addr1="${ns1_v6}"
-	link_addr2="${ns2_v6}"
-else
-	link_addr1="${addr1}"
-	link_addr2="${addr2}"
-fi
-
-# serverside, insert decap module
-# server is still running
-# client can connect again
-ip netns exec "${ns2}" ip link add name testtun0 type "${ttype}" \
-	${tmode} remote "${link_addr1}" local "${link_addr2}" $targs
-
-expect_tun_fail=0
-
-if [[ "$tuntype" == "ip6udp" && "$mac" == "mpls" ]]; then
-	# No support for MPLS IPv6 fou tunnel; expect failure.
-	expect_tun_fail=1
-elif [[ "$tuntype" =~ "udp" && "$mac" == "eth" ]]; then
-	# No support for TEB fou tunnel; expect failure.
-	expect_tun_fail=1
-elif [[ "$tuntype" =~ (gre|vxlan) && "$mac" == "eth" ]]; then
-	# Share ethernet address between tunnel/veth2 so L2 decap works.
-	ethaddr=$(ip netns exec "${ns2}" ip link show veth2 | \
-		  awk '/ether/ { print $2 }')
-	ip netns exec "${ns2}" ip link set testtun0 address $ethaddr
-elif [[ "$mac" == "mpls" ]]; then
-	modprobe mpls_iptunnel ||true
-	modprobe mpls_gso ||true
-	ip netns exec "${ns2}" sysctl -qw net.mpls.platform_labels=65536
-	ip netns exec "${ns2}" ip -f mpls route add 1000 dev lo
-	ip netns exec "${ns2}" ip link set lo up
-	ip netns exec "${ns2}" sysctl -qw net.mpls.conf.testtun0.input=1
-	ip netns exec "${ns2}" sysctl -qw net.ipv4.conf.lo.rp_filter=0
-fi
-
-# Because packets are decapped by the tunnel they arrive on testtun0 from
-# the IP stack perspective.  Ensure reverse path filtering is disabled
-# otherwise we drop the TCP SYN as arriving on testtun0 instead of the
-# expected veth2 (veth2 is where 192.168.1.2 is configured).
-ip netns exec "${ns2}" sysctl -qw net.ipv4.conf.all.rp_filter=0
-# rp needs to be disabled for both all and testtun0 as the rp value is
-# selected as the max of the "all" and device-specific values.
-ip netns exec "${ns2}" sysctl -qw net.ipv4.conf.testtun0.rp_filter=0
-ip netns exec "${ns2}" ip link set dev testtun0 up
-if [[ "$expect_tun_fail" == 1 ]]; then
-	# This tunnel mode is not supported, so we expect failure.
-	echo "test bpf encap with tunnel device decap (expect failure)"
-	! client_connect
-else
-	echo "test bpf encap with tunnel device decap"
-	client_connect
-	verify_data
-	server_listen
-	wait_for_port ${port} ${netcat_opt}
-fi
-
-# serverside, use BPF for decap
-ip netns exec "${ns2}" ip link del dev testtun0
-ip netns exec "${ns2}" tc qdisc add dev veth2 clsact
-ip netns exec "${ns2}" tc filter add dev veth2 ingress \
-	bpf direct-action object-file ${BPF_FILE} section decap
-echo "test bpf encap with bpf decap"
-client_connect
-verify_data
-
-echo OK