selftests/bpf: expand bpf tunnel test to ipv6

The test only uses ipv4 so far, expand to ipv6.
This is mostly a boilerplate near copy of the ipv4 path.

Signed-off-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

1 files changed, 98 insertions, 18 deletions

diff --git a/tools/testing/selftests/bpf/progs/test_tc_tunnel.c b/tools/testing/selftests/bpf/progs/test_tc_tunnel.c
index 25db148635ab..591f540ce513 100644
--- a/tools/testing/selftests/bpf/progs/test_tc_tunnel.c
+++ b/tools/testing/selftests/bpf/progs/test_tc_tunnel.c
@@ -7,6 +7,7 @@
 #include <linux/if_ether.h>
 #include <linux/in.h>
 #include <linux/ip.h>
+#include <linux/ipv6.h>
 #include <linux/tcp.h>
 #include <linux/pkt_cls.h>
 #include <linux/types.h>
@@ -31,15 +32,11 @@ static __always_inline void set_ipv4_csum(struct iphdr *iph)
 	iph->check = ~((csum & 0xffff) + (csum >> 16));
 }
 
-SEC("encap")
-int encap_f(struct __sk_buff *skb)
+static int encap_ipv4(struct __sk_buff *skb)
 {
 	struct iphdr iph_outer, iph_inner;
 	struct tcphdr tcph;
 
-	if (skb->protocol != __bpf_constant_htons(ETH_P_IP))
-		return TC_ACT_OK;
-
 	if (bpf_skb_load_bytes(skb, ETH_HLEN, &iph_inner,
 			       sizeof(iph_inner)) < 0)
 		return TC_ACT_OK;
@@ -80,35 +77,118 @@ int encap_f(struct __sk_buff *skb)
 	return TC_ACT_OK;
 }
 
-SEC("decap")
-int decap_f(struct __sk_buff *skb)
+static int encap_ipv6(struct __sk_buff *skb)
 {
-	struct iphdr iph_outer, iph_inner;
+	struct ipv6hdr iph_outer, iph_inner;
+	struct tcphdr tcph;
 
-	if (skb->protocol != __bpf_constant_htons(ETH_P_IP))
+	if (bpf_skb_load_bytes(skb, ETH_HLEN, &iph_inner,
+			       sizeof(iph_inner)) < 0)
 		return TC_ACT_OK;
 
-	if (bpf_skb_load_bytes(skb, ETH_HLEN, &iph_outer,
-			       sizeof(iph_outer)) < 0)
+	/* filter only packets we want */
+	if (bpf_skb_load_bytes(skb, ETH_HLEN + sizeof(iph_inner),
+			       &tcph, sizeof(tcph)) < 0)
 		return TC_ACT_OK;
 
-	if (iph_outer.ihl != 5 || iph_outer.protocol != IPPROTO_IPIP)
+	if (tcph.dest != __bpf_constant_htons(cfg_port))
+		return TC_ACT_OK;
+
+	/* add room between mac and network header */
+	if (bpf_skb_adjust_room(skb, sizeof(iph_outer), BPF_ADJ_ROOM_NET, 0))
+		return TC_ACT_SHOT;
+
+	/* prepare new outer network header */
+	iph_outer = iph_inner;
+	iph_outer.nexthdr = IPPROTO_IPV6;
+	iph_outer.payload_len = bpf_htons(sizeof(iph_outer) +
+					  bpf_ntohs(iph_outer.payload_len));
+
+	/* store new outer network header */
+	if (bpf_skb_store_bytes(skb, ETH_HLEN, &iph_outer, sizeof(iph_outer),
+				BPF_F_INVALIDATE_HASH) < 0)
+		return TC_ACT_SHOT;
+
+	/* bpf_skb_adjust_room has moved header to start of room: restore */
+	if (bpf_skb_store_bytes(skb, ETH_HLEN + sizeof(iph_outer),
+				&iph_inner, sizeof(iph_inner),
+				BPF_F_INVALIDATE_HASH) < 0)
+		return TC_ACT_SHOT;
+
+	return TC_ACT_OK;
+}
+
+SEC("encap")
+int encap_f(struct __sk_buff *skb)
+{
+	switch (skb->protocol) {
+	case __bpf_constant_htons(ETH_P_IP):
+		return encap_ipv4(skb);
+	case __bpf_constant_htons(ETH_P_IPV6):
+		return encap_ipv6(skb);
+	default:
+		/* does not match, ignore */
 		return TC_ACT_OK;
+	}
+}
 
-	if (bpf_skb_load_bytes(skb, ETH_HLEN + sizeof(iph_outer),
-			       &iph_inner, sizeof(iph_inner)) < 0)
+static int decap_internal(struct __sk_buff *skb, int off, int len)
+{
+	char buf[sizeof(struct ipv6hdr)];
+
+	if (bpf_skb_load_bytes(skb, off + len, &buf, len) < 0)
 		return TC_ACT_OK;
 
-	if (bpf_skb_adjust_room(skb, -(int)sizeof(iph_outer),
-				BPF_ADJ_ROOM_NET, 0))
+	if (bpf_skb_adjust_room(skb, -len, BPF_ADJ_ROOM_NET, 0))
 		return TC_ACT_SHOT;
 
 	/* bpf_skb_adjust_room has moved outer over inner header: restore */
-	if (bpf_skb_store_bytes(skb, ETH_HLEN, &iph_inner, sizeof(iph_inner),
-				BPF_F_INVALIDATE_HASH) < 0)
+	if (bpf_skb_store_bytes(skb, off, buf, len, BPF_F_INVALIDATE_HASH) < 0)
 		return TC_ACT_SHOT;
 
 	return TC_ACT_OK;
 }
 
+static int decap_ipv4(struct __sk_buff *skb)
+{
+	struct iphdr iph_outer;
+
+	if (bpf_skb_load_bytes(skb, ETH_HLEN, &iph_outer,
+			       sizeof(iph_outer)) < 0)
+		return TC_ACT_OK;
+
+	if (iph_outer.ihl != 5 || iph_outer.protocol != IPPROTO_IPIP)
+		return TC_ACT_OK;
+
+	return decap_internal(skb, ETH_HLEN, sizeof(iph_outer));
+}
+
+static int decap_ipv6(struct __sk_buff *skb)
+{
+	struct ipv6hdr iph_outer;
+
+	if (bpf_skb_load_bytes(skb, ETH_HLEN, &iph_outer,
+			       sizeof(iph_outer)) < 0)
+		return TC_ACT_OK;
+
+	if (iph_outer.nexthdr != IPPROTO_IPV6)
+		return TC_ACT_OK;
+
+	return decap_internal(skb, ETH_HLEN, sizeof(iph_outer));
+}
+
+SEC("decap")
+int decap_f(struct __sk_buff *skb)
+{
+	switch (skb->protocol) {
+	case __bpf_constant_htons(ETH_P_IP):
+		return decap_ipv4(skb);
+	case __bpf_constant_htons(ETH_P_IPV6):
+		return decap_ipv6(skb);
+	default:
+		/* does not match, ignore */
+		return TC_ACT_OK;
+	}
+}
+
 char __license[] SEC("license") = "GPL";