[PATCH bpf-next 06/10] selftests/bpf: add gre packets testing to flow_dissector

[eBPF Foundation]

The bpf_flow program is able to handle GRE headers in IP packets. Add a
few test data input simulating those GRE packets, with 2 different
cases:
- parse GRE and the encapsulated packet
- parse GRE only

Signed-off-by: Alexis Lothoré (eBPF Foundation) <alexis.loth...@bootlin.com>
---
 .../selftests/bpf/prog_tests/flow_dissector.c      | 76 ++++++++++++++++++++++
 1 file changed, 76 insertions(+)

diff --git a/tools/testing/selftests/bpf/prog_tests/flow_dissector.c 
b/tools/testing/selftests/bpf/prog_tests/flow_dissector.c
index 
8ab3268ef4c92fc33ac40e8f8f963a4d8b6551a8..05f3953c6266efdedeb74a81969ccfdabf009ccd
 100644
--- a/tools/testing/selftests/bpf/prog_tests/flow_dissector.c
+++ b/tools/testing/selftests/bpf/prog_tests/flow_dissector.c
@@ -63,6 +63,19 @@ struct dvlan_ipv6_pkt {
        struct tcphdr tcp;
 } __packed;
 
+struct gre_base_hdr {
+       __be16 flags;
+       __be16 protocol;
+} gre_base_hdr;
+
+struct gre_minimal_pkt {
+       struct ethhdr eth;
+       struct iphdr iph;
+       struct gre_base_hdr gre_hdr;
+       struct iphdr iph_inner;
+       struct tcphdr tcp;
+} __packed;
+
 struct test {
        const char *name;
        union {
@@ -72,6 +85,7 @@ struct test {
                struct ipv6_pkt ipv6;
                struct ipv6_frag_pkt ipv6_frag;
                struct dvlan_ipv6_pkt dvlan_ipv6;
+               struct gre_minimal_pkt gre_minimal;
        } pkt;
        struct bpf_flow_keys keys;
        __u32 flags;
@@ -417,6 +431,68 @@ struct test tests[] = {
                },
                .retval = BPF_FLOW_DISSECTOR_CONTINUE,
        },
+       {
+               .name = "ip-gre",
+               .pkt.gre_minimal = {
+                       .eth.h_proto = __bpf_constant_htons(ETH_P_IP),
+                       .iph.ihl = 5,
+                       .iph.protocol = IPPROTO_GRE,
+                       .iph.tot_len = __bpf_constant_htons(MAGIC_BYTES),
+                       .gre_hdr = {
+                               .flags = 0,
+                               .protocol = __bpf_constant_htons(ETH_P_IP),
+                       },
+                       .iph_inner.ihl = 5,
+                       .iph_inner.protocol = IPPROTO_TCP,
+                       .iph_inner.tot_len =
+                               __bpf_constant_htons(MAGIC_BYTES -
+                               sizeof(struct iphdr)),
+                       .tcp.doff = 5,
+                       .tcp.source = 80,
+                       .tcp.dest = 8080,
+               },
+               .keys = {
+                       .nhoff = ETH_HLEN,
+                       .thoff = ETH_HLEN + sizeof(struct iphdr) * 2 +
+                                sizeof(struct gre_base_hdr),
+                       .addr_proto = ETH_P_IP,
+                       .ip_proto = IPPROTO_TCP,
+                       .n_proto = __bpf_constant_htons(ETH_P_IP),
+                       .is_encap = true,
+                       .sport = 80,
+                       .dport = 8080,
+               },
+               .retval = BPF_OK,
+       },
+       {
+               .name = "ip-gre-no-encap",
+               .pkt.ipip = {
+                       .eth.h_proto = __bpf_constant_htons(ETH_P_IP),
+                       .iph.ihl = 5,
+                       .iph.protocol = IPPROTO_GRE,
+                       .iph.tot_len = __bpf_constant_htons(MAGIC_BYTES),
+                       .iph_inner.ihl = 5,
+                       .iph_inner.protocol = IPPROTO_TCP,
+                       .iph_inner.tot_len =
+                               __bpf_constant_htons(MAGIC_BYTES -
+                               sizeof(struct iphdr)),
+                       .tcp.doff = 5,
+                       .tcp.source = 80,
+                       .tcp.dest = 8080,
+               },
+               .keys = {
+                       .flags = BPF_FLOW_DISSECTOR_F_STOP_AT_ENCAP,
+                       .nhoff = ETH_HLEN,
+                       .thoff = ETH_HLEN + sizeof(struct iphdr)
+                                + sizeof(struct gre_base_hdr),
+                       .addr_proto = ETH_P_IP,
+                       .ip_proto = IPPROTO_GRE,
+                       .n_proto = __bpf_constant_htons(ETH_P_IP),
+                       .is_encap = true,
+               },
+               .flags = BPF_FLOW_DISSECTOR_F_STOP_AT_ENCAP,
+               .retval = BPF_OK,
+       },
 };
 
 static int create_tap(const char *ifname)

-- 
2.47.0