Subject: Re: [PATCH ipsec-next v1 5/7] bpf: selftests: test_tunnel: Use vmlinux.h declarations

From: Yonghong Song <[email-masked]>
Date: Sat, 25 Nov 2023 16:34:36 -0800

On 11/22/23 1:20 PM, Daniel Xu wrote:
> vmlinux.h declarations are more ergnomic, especially when working with
> kfuncs. The uapi headers are often incomplete for kfunc definitions.
>
> Co-developed-by: Antony Antony <[email-masked]>
> Signed-off-by: Antony Antony <[email-masked]>
> Signed-off-by: Daniel Xu <[email-masked]>
> ---
>   .../selftests/bpf/progs/bpf_tracing_net.h     |  1 +
>   .../selftests/bpf/progs/test_tunnel_kern.c    | 48 ++++---------------
>   2 files changed, 9 insertions(+), 40 deletions(-)
>
> diff --git a/tools/testing/selftests/bpf/progs/bpf_tracing_net.h b/tools/testing/selftests/bpf/progs/bpf_tracing_net.h
> index 0b793a102791..1bdc680b0e0e 100644
> --- a/tools/testing/selftests/bpf/progs/bpf_tracing_net.h
> +++ b/tools/testing/selftests/bpf/progs/bpf_tracing_net.h
> @@ -26,6 +26,7 @@
>   #define IPV6_AUTOFLOWLABEL	70
>   
>   #define TC_ACT_UNSPEC		(-1)
> +#define TC_ACT_OK		0
>   #define TC_ACT_SHOT		2
>   
>   #define SOL_TCP			6
> diff --git a/tools/testing/selftests/bpf/progs/test_tunnel_kern.c b/tools/testing/selftests/bpf/progs/test_tunnel_kern.c
> index f66af753bbbb..3065a716544d 100644
> --- a/tools/testing/selftests/bpf/progs/test_tunnel_kern.c
> +++ b/tools/testing/selftests/bpf/progs/test_tunnel_kern.c
> @@ -6,62 +6,30 @@
>    * modify it under the terms of version 2 of the GNU General Public
>    * License as published by the Free Software Foundation.
>    */
> -#include <stddef.h>
> -#include <string.h>
> -#include <arpa/inet.h>
> -#include <linux/bpf.h>
> -#include <linux/if_ether.h>
> -#include <linux/if_packet.h>
> -#include <linux/if_tunnel.h>
> -#include <linux/ip.h>
> -#include <linux/ipv6.h>
> -#include <linux/icmp.h>
> -#include <linux/types.h>
> -#include <linux/socket.h>
> -#include <linux/pkt_cls.h>
> -#include <linux/erspan.h>
> -#include <linux/udp.h>
> +#include "vmlinux.h"
>   #include <bpf/bpf_helpers.h>
>   #include <bpf/bpf_endian.h>
> +#include "bpf_kfuncs.h"
> +#include "bpf_tracing_net.h"
>   
>   #define log_err(__ret) bpf_printk("ERROR line:%d ret:%d\n", __LINE__, __ret)
>   
> -#define VXLAN_UDP_PORT 4789
> +#define VXLAN_UDP_PORT		4789
> +#define ETH_P_IP		0x0800
> +#define PACKET_HOST		0
> +#define TUNNEL_CSUM		bpf_htons(0x01)
> +#define TUNNEL_KEY		bpf_htons(0x04)
>   
>   /* Only IPv4 address assigned to veth1.
>    * 172.16.1.200
>    */
>   #define ASSIGNED_ADDR_VETH1 0xac1001c8
>   
> -struct geneve_opt {
> -	__be16	opt_class;
> -	__u8	type;
> -	__u8	length:5;
> -	__u8	r3:1;
> -	__u8	r2:1;
> -	__u8	r1:1;
> -	__u8	opt_data[8]; /* hard-coded to 8 byte */
> -};
> -
>   struct vxlanhdr {
>   	__be32 vx_flags;
>   	__be32 vx_vni;
>   } __attribute__((packed));

In my particular setup, I have struct vxlanhdr defined in vmlinux.h so
I hit a compilation failure.

>   
> -struct vxlan_metadata {
> -	__u32     gbp;
> -};
> -
> -struct bpf_fou_encap {
> -	__be16 sport;
> -	__be16 dport;
> -};
> -
> -enum bpf_fou_encap_type {
> -	FOU_BPF_ENCAP_FOU,
> -	FOU_BPF_ENCAP_GUE,
> -};
> -
>   int bpf_skb_set_fou_encap(struct __sk_buff *skb_ctx,
>   			  struct bpf_fou_encap *encap, int type) __ksym;
>   int bpf_skb_get_fou_encap(struct __sk_buff *skb_ctx,