[PATCH bpf-next v7 6/6] selftests/bpf: tc_tunnel - validate decap GSO and encapsulation state

Nick Hudson <[email protected]>
Newsgroups org.kernel.vger.netdev,org.kernel.vger.bpf,org.kernel.vger.linux-kernel,org.kernel.vger.linux-kselftest
Message-ID <[email protected]> 
tc_tunnel only partially validated decap state and missed some tunnel
cases. In particular, IPXIP decap checks were not exercised for
IPIP/SIT paths, and non-GSO decap encapsulation state was not
verified.

Tighten the test by:

- setting DECAP_IPXIP4/6 flags for IPIP/SIT/IP6 decap paths based on
  the outer tunnel header family;
- requiring needed DECAP enum values via CO-RE enum existence checks
  so missing kernel support fails fast;
- validating post-decap tunnel state for both GSO and non-GSO packets:
  expected gso_type bits must be cleared and skb->encapsulation must
  match remaining tunnel flags;
- removing forced TSO disable in the test harness so GSO validation is
  exercised.

This improves coverage for decap tunnel-state regressions and ensures
sit_none/ipip-style paths are checked correctly.

Signed-off-by: Nick Hudson <[email protected]>
---
 .../selftests/bpf/prog_tests/test_tc_tunnel.c |  1 -
 .../selftests/bpf/progs/test_tc_tunnel.c      | 91 +++++++++++++++++--
 2 files changed, 84 insertions(+), 8 deletions(-)

diff --git a/tools/testing/selftests/bpf/prog_tests/test_tc_tunnel.c b/tools/testing/selftests/bpf/prog_tests/test_tc_tunnel.c
index 1aa7c9463980..67ba27d69347 100644
--- a/tools/testing/selftests/bpf/prog_tests/test_tc_tunnel.c
+++ b/tools/testing/selftests/bpf/prog_tests/test_tc_tunnel.c
@@ -438,7 +438,6 @@ static int setup(void)
 	SYS(fail_close_ns_client, "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_close_ns_client, "ethtool -K veth1 tso off");
 	SYS(fail_close_ns_client, "ip link set veth1 up");
 	nstoken_server = open_netns(SERVER_NS);
 	if (!ASSERT_OK_PTR(nstoken_server, "open server ns"))
diff --git a/tools/testing/selftests/bpf/progs/test_tc_tunnel.c b/tools/testing/selftests/bpf/progs/test_tc_tunnel.c
index 7376df405a6b..853bca962910 100644
--- a/tools/testing/selftests/bpf/progs/test_tc_tunnel.c
+++ b/tools/testing/selftests/bpf/progs/test_tc_tunnel.c
@@ -6,6 +6,7 @@
 
 #include <bpf/bpf_helpers.h>
 #include <bpf/bpf_endian.h>
+#include <bpf/bpf_core_read.h>
 #include "bpf_tracing_net.h"
 #include "bpf_compiler.h"
 
@@ -37,6 +38,22 @@ struct vxlanhdr___local {
 
 #define	EXTPROTO_VXLAN	0x1
 
+#define SKB_GSO_UDP_TUNNEL_MASK	(SKB_GSO_UDP_TUNNEL |			\
+				 SKB_GSO_UDP_TUNNEL_CSUM)
+
+#define SKB_GSO_TUNNEL_MASK	(SKB_GSO_UDP_TUNNEL_MASK |		\
+				 SKB_GSO_GRE |				\
+				 SKB_GSO_GRE_CSUM |			\
+				 SKB_GSO_IPXIP4 |			\
+				 SKB_GSO_IPXIP6 |			\
+				 SKB_GSO_ESP)
+
+#define BPF_F_ADJ_ROOM_DECAP_L4_MASK	(BPF_F_ADJ_ROOM_DECAP_L4_UDP |	\
+					 BPF_F_ADJ_ROOM_DECAP_L4_GRE)
+
+#define BPF_F_ADJ_ROOM_DECAP_IPXIP_MASK	(BPF_F_ADJ_ROOM_DECAP_IPXIP4 |	\
+					 BPF_F_ADJ_ROOM_DECAP_IPXIP6)
+
 #define	VXLAN_FLAGS     bpf_htonl(1<<27)
 #define	VNI_ID		1
 #define	VXLAN_VNI	bpf_htonl(VNI_ID << 8)
@@ -589,9 +606,12 @@ int __encap_ip6vxlan_eth(struct __sk_buff *skb)
 		return TC_ACT_OK;
 }
 
-static int decap_internal(struct __sk_buff *skb, int off, int len, char proto)
+static int decap_internal(struct __sk_buff *skb, int off, int len, char proto,
+			  __u64 ipxip_flag)
 {
 	__u64 flags = BPF_F_ADJ_ROOM_FIXED_GSO;
+	struct sk_buff *kskb;
+	struct skb_shared_info *shinfo;
 	struct ipv6_opt_hdr ip6_opt_hdr;
 	struct gre_hdr greh;
 	struct udphdr udph;
@@ -599,10 +619,12 @@ static int decap_internal(struct __sk_buff *skb, int off, int len, char proto)
 
 	switch (proto) {
 	case IPPROTO_IPIP:
-		flags |= BPF_F_ADJ_ROOM_DECAP_L3_IPV4;
+		flags |= BPF_F_ADJ_ROOM_DECAP_L3_IPV4 |
+			 ipxip_flag;
 		break;
 	case IPPROTO_IPV6:
-		flags |= BPF_F_ADJ_ROOM_DECAP_L3_IPV6;
+		flags |= BPF_F_ADJ_ROOM_DECAP_L3_IPV6 |
+			 ipxip_flag;
 		break;
 	case NEXTHDR_DEST:
 		if (bpf_skb_load_bytes(skb, off + len, &ip6_opt_hdr,
@@ -610,10 +632,12 @@ static int decap_internal(struct __sk_buff *skb, int off, int len, char proto)
 			return TC_ACT_OK;
 		switch (ip6_opt_hdr.nexthdr) {
 		case IPPROTO_IPIP:
-			flags |= BPF_F_ADJ_ROOM_DECAP_L3_IPV4;
+			flags |= BPF_F_ADJ_ROOM_DECAP_L3_IPV4 |
+				 ipxip_flag;
 			break;
 		case IPPROTO_IPV6:
-			flags |= BPF_F_ADJ_ROOM_DECAP_L3_IPV6;
+			flags |= BPF_F_ADJ_ROOM_DECAP_L3_IPV6 |
+				 ipxip_flag;
 			break;
 		default:
 			return TC_ACT_OK;
@@ -621,6 +645,11 @@ static int decap_internal(struct __sk_buff *skb, int off, int len, char proto)
 		break;
 	case IPPROTO_GRE:
 		olen += sizeof(struct gre_hdr);
+		if (!bpf_core_enum_value_exists(enum bpf_adj_room_flags,
+						BPF_F_ADJ_ROOM_DECAP_L4_GRE))
+			return TC_ACT_SHOT;
+		flags |= BPF_F_ADJ_ROOM_DECAP_L4_GRE;
+
 		if (bpf_skb_load_bytes(skb, off + len, &greh, sizeof(greh)) < 0)
 			return TC_ACT_OK;
 		switch (bpf_ntohs(greh.protocol)) {
@@ -634,6 +663,10 @@ static int decap_internal(struct __sk_buff *skb, int off, int len, char proto)
 		break;
 	case IPPROTO_UDP:
 		olen += sizeof(struct udphdr);
+		if (!bpf_core_enum_value_exists(enum bpf_adj_room_flags,
+						BPF_F_ADJ_ROOM_DECAP_L4_UDP))
+			return TC_ACT_SHOT;
+		flags |= BPF_F_ADJ_ROOM_DECAP_L4_UDP;
 		if (bpf_skb_load_bytes(skb, off + len, &udph, sizeof(udph)) < 0)
 			return TC_ACT_OK;
 		switch (bpf_ntohs(udph.dest)) {
@@ -655,6 +688,40 @@ static int decap_internal(struct __sk_buff *skb, int off, int len, char proto)
 	if (bpf_skb_adjust_room(skb, -olen, BPF_ADJ_ROOM_MAC, flags))
 		return TC_ACT_SHOT;
 
+	kskb = bpf_cast_to_kern_ctx(skb);
+	shinfo = bpf_core_cast(kskb->head + kskb->end, struct skb_shared_info);
+	if (shinfo->gso_size) {
+		if ((flags & BPF_F_ADJ_ROOM_DECAP_L4_UDP) &&
+		    (shinfo->gso_type & SKB_GSO_UDP_TUNNEL_MASK))
+			return TC_ACT_SHOT;
+
+		if ((flags & BPF_F_ADJ_ROOM_DECAP_L4_GRE) &&
+		    (shinfo->gso_type & (SKB_GSO_GRE | SKB_GSO_GRE_CSUM)))
+			return TC_ACT_SHOT;
+
+		if ((flags & BPF_F_ADJ_ROOM_DECAP_IPXIP4) &&
+		    (shinfo->gso_type & SKB_GSO_IPXIP4))
+			return TC_ACT_SHOT;
+
+		if ((flags & BPF_F_ADJ_ROOM_DECAP_IPXIP6) &&
+		    (shinfo->gso_type & SKB_GSO_IPXIP6))
+			return TC_ACT_SHOT;
+
+		if (flags & (BPF_F_ADJ_ROOM_DECAP_L4_MASK |
+			     BPF_F_ADJ_ROOM_DECAP_IPXIP_MASK)) {
+			if ((shinfo->gso_type & SKB_GSO_TUNNEL_MASK) &&
+			    !kskb->encapsulation)
+				return TC_ACT_SHOT;
+			if (!(shinfo->gso_type & SKB_GSO_TUNNEL_MASK) &&
+			    kskb->encapsulation)
+				return TC_ACT_SHOT;
+		}
+	} else if ((flags & (BPF_F_ADJ_ROOM_DECAP_L4_MASK |
+			     BPF_F_ADJ_ROOM_DECAP_IPXIP_MASK)) &&
+		   kskb->encapsulation) {
+		return TC_ACT_SHOT;
+	}
+
 	return TC_ACT_OK;
 }
 
@@ -662,6 +729,10 @@ static int decap_ipv4(struct __sk_buff *skb)
 {
 	struct iphdr iph_outer;
 
+	if (!bpf_core_enum_value_exists(enum bpf_adj_room_flags,
+					BPF_F_ADJ_ROOM_DECAP_IPXIP4))
+		return TC_ACT_SHOT;
+
 	if (bpf_skb_load_bytes(skb, ETH_HLEN, &iph_outer,
 			       sizeof(iph_outer)) < 0)
 		return TC_ACT_OK;
@@ -670,19 +741,25 @@ static int decap_ipv4(struct __sk_buff *skb)
 		return TC_ACT_OK;
 
 	return decap_internal(skb, ETH_HLEN, sizeof(iph_outer),
-			      iph_outer.protocol);
+			      iph_outer.protocol,
+			      BPF_F_ADJ_ROOM_DECAP_IPXIP4);
 }
 
 static int decap_ipv6(struct __sk_buff *skb)
 {
 	struct ipv6hdr iph_outer;
 
+	if (!bpf_core_enum_value_exists(enum bpf_adj_room_flags,
+					BPF_F_ADJ_ROOM_DECAP_IPXIP6))
+		return TC_ACT_SHOT;
+
 	if (bpf_skb_load_bytes(skb, ETH_HLEN, &iph_outer,
 			       sizeof(iph_outer)) < 0)
 		return TC_ACT_OK;
 
 	return decap_internal(skb, ETH_HLEN, sizeof(iph_outer),
-			      iph_outer.nexthdr);
+			      iph_outer.nexthdr,
+			      BPF_F_ADJ_ROOM_DECAP_IPXIP6);
 }
 
 SEC("tc")
-- 
2.34.1
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