On 7/26/19 12:52 AM, Stanislav Fomichev wrote:
> Exit as soon as we found that packet is encapped when
> BPF_FLOW_DISSECTOR_F_STOP_AT_ENCAP is passed.
> Add appropriate selftest cases.
>
> v2:
> * Subtract sizeof(struct iphdr) from .iph_inner.tot_len (Willem de Bruijn)
>
> Acked-by: Petar Penkov <ppenkov@xxxxxxxxxx>
> Acked-by: Willem de Bruijn <willemb@xxxxxxxxxx>
> Acked-by: Song Liu <songliubraving@xxxxxx>
> Cc: Song Liu <songliubraving@xxxxxx>
> Cc: Willem de Bruijn <willemb@xxxxxxxxxx>
> Cc: Petar Penkov <ppenkov@xxxxxxxxxx>
> Signed-off-by: Stanislav Fomichev <sdf@xxxxxxxxxx>
> ---
> .../selftests/bpf/prog_tests/flow_dissector.c | 64 +++++++++++++++++++
> tools/testing/selftests/bpf/progs/bpf_flow.c | 8 +++
> 2 files changed, 72 insertions(+)
>
> diff --git a/tools/testing/selftests/bpf/prog_tests/flow_dissector.c b/tools/testing/selftests/bpf/prog_tests/flow_dissector.c
> index ef83f145a6f1..700d73d2f22a 100644
> --- a/tools/testing/selftests/bpf/prog_tests/flow_dissector.c
> +++ b/tools/testing/selftests/bpf/prog_tests/flow_dissector.c
> @@ -41,6 +41,13 @@ struct ipv4_pkt {
> struct tcphdr tcp;
> } __packed;
>
> +struct ipip_pkt {
> + struct ethhdr eth;
> + struct iphdr iph;
> + struct iphdr iph_inner;
> + struct tcphdr tcp;
> +} __packed;
> +
> struct svlan_ipv4_pkt {
> struct ethhdr eth;
> __u16 vlan_tci;
> @@ -82,6 +89,7 @@ struct test {
> union {
> struct ipv4_pkt ipv4;
> struct svlan_ipv4_pkt svlan_ipv4;
> + struct ipip_pkt ipip;
> struct ipv6_pkt ipv6;
> struct ipv6_frag_pkt ipv6_frag;
> struct dvlan_ipv6_pkt dvlan_ipv6;
> @@ -303,6 +311,62 @@ struct test tests[] = {
> },
> .flags = BPF_FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL,
> },
> + {
> + .name = "ipip-encap",
> + .pkt.ipip = {
> + .eth.h_proto = __bpf_constant_htons(ETH_P_IP),
> + .iph.ihl = 5,
> + .iph.protocol = IPPROTO_IPIP,
> + .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 = {
> + .nhoff = 0,
> + .nhoff = ETH_HLEN,
clang emits a warning because nhoff is defined twice.
> + .thoff = ETH_HLEN + sizeof(struct iphdr) +
> + sizeof(struct iphdr),
> + .addr_proto = ETH_P_IP,
> + .ip_proto = IPPROTO_TCP,
> + .n_proto = __bpf_constant_htons(ETH_P_IP),
> + .is_encap = true,
> + .sport = 80,
> + .dport = 8080,
> + },
> + },
> + {
> + .name = "ipip-no-encap",
> + .pkt.ipip = {
> + .eth.h_proto = __bpf_constant_htons(ETH_P_IP),
> + .iph.ihl = 5,
> + .iph.protocol = IPPROTO_IPIP,
> + .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),
> + .addr_proto = ETH_P_IP,
> + .ip_proto = IPPROTO_IPIP,
> + .n_proto = __bpf_constant_htons(ETH_P_IP),
> + .is_encap = true,
> + },
> + .flags = BPF_FLOW_DISSECTOR_F_STOP_AT_ENCAP,
> + },
> };
>
> static int create_tap(const char *ifname)
> diff --git a/tools/testing/selftests/bpf/progs/bpf_flow.c b/tools/testing/selftests/bpf/progs/bpf_flow.c
> index 7fbfa22f33df..08bd8b9d58d0 100644
> --- a/tools/testing/selftests/bpf/progs/bpf_flow.c
> +++ b/tools/testing/selftests/bpf/progs/bpf_flow.c
> @@ -167,9 +167,15 @@ static __always_inline int parse_ip_proto(struct __sk_buff *skb, __u8 proto)
> return export_flow_keys(keys, BPF_OK);
> case IPPROTO_IPIP:
> keys->is_encap = true;
> + if (keys->flags & BPF_FLOW_DISSECTOR_F_STOP_AT_ENCAP)
> + return export_flow_keys(keys, BPF_OK);
> +
> return parse_eth_proto(skb, bpf_htons(ETH_P_IP));
> case IPPROTO_IPV6:
> keys->is_encap = true;
> + if (keys->flags & BPF_FLOW_DISSECTOR_F_STOP_AT_ENCAP)
> + return export_flow_keys(keys, BPF_OK);
> +
> return parse_eth_proto(skb, bpf_htons(ETH_P_IPV6));
> case IPPROTO_GRE:
> gre = bpf_flow_dissect_get_header(skb, sizeof(*gre), &_gre);
> @@ -189,6 +195,8 @@ static __always_inline int parse_ip_proto(struct __sk_buff *skb, __u8 proto)
> keys->thoff += 4; /* Step over sequence number */
>
> keys->is_encap = true;
> + if (keys->flags & BPF_FLOW_DISSECTOR_F_STOP_AT_ENCAP)
> + return export_flow_keys(keys, BPF_OK);
>
> if (gre->proto == bpf_htons(ETH_P_TEB)) {
> eth = bpf_flow_dissect_get_header(skb, sizeof(*eth),
>
