[ovs-dev] [PATCH] nsh: Fix packet format to match IETF NSH draft.

[Yang, Yi]

On Thu, Nov 02, 2017 at 04:51:52AM +0800, Ben Pfaff wrote:
> The NSH draft added a TTL field.  This adds basic support.
> 
> CC: Yi Yang <yi.y.yang at intel.com>
> CC: Jan Scheurich <jan.scheurich at ericsson.com>
> Signed-off-by: Ben Pfaff <blp at ovn.org>
> ---
>  include/openvswitch/nsh.h | 11 +++++++----
>  lib/flow.c                |  2 +-
>  lib/odp-execute.c         | 10 +++++-----
>  lib/packets.c             |  4 +++-
>  4 files changed, 16 insertions(+), 11 deletions(-)
> 
> diff --git a/include/openvswitch/nsh.h b/include/openvswitch/nsh.h
> index a3611d0896b2..4d83bad1af81 100644
> --- a/include/openvswitch/nsh.h
> +++ b/include/openvswitch/nsh.h
> @@ -62,7 +62,7 @@ struct nsh_md2_tlv {
>  };
>  
>  struct nsh_hdr {
> -    ovs_be16 ver_flags_len;
> +    ovs_be16 ver_flags_ttl_len;
>      uint8_t md_type;
>      uint8_t next_proto;
>      ovs_16aligned_be32 path_hdr;
> @@ -75,8 +75,10 @@ struct nsh_hdr {
>  /* Masking NSH header fields. */
>  #define NSH_VER_MASK       0xc000
>  #define NSH_VER_SHIFT      14
> -#define NSH_FLAGS_MASK     0x3fc0
> -#define NSH_FLAGS_SHIFT    6
> +#define NSH_FLAGS_MASK     0x3000
> +#define NSH_FLAGS_SHIFT    12
> +#define NSH_TTL_MASK       0x0fc0
> +#define NSH_TTL_SHIFT      6
>  #define NSH_LEN_MASK       0x003f
>  #define NSH_LEN_SHIFT      0
>  
> @@ -113,7 +115,8 @@ struct nsh_hdr {
>  static inline uint16_t
>  nsh_hdr_len(const struct nsh_hdr *nsh)
>  {
> -    return ((ntohs(nsh->ver_flags_len) & NSH_LEN_MASK) >> NSH_LEN_SHIFT) << 2;
> +    return ((ntohs(nsh->ver_flags_ttl_len) & NSH_LEN_MASK)
> +            >> NSH_LEN_SHIFT) << 2;
>  }
>  
>  static inline struct nsh_md1_ctx *
> diff --git a/lib/flow.c b/lib/flow.c
> index 4d2b7747a124..57b6c597d207 100644
> --- a/lib/flow.c
> +++ b/lib/flow.c
> @@ -546,7 +546,7 @@ parse_nsh(const void **datap, size_t *sizep, struct flow_nsh *key)
>  
>      memset(key, 0, sizeof(struct flow_nsh));
>  
> -    ver_flags_len = ntohs(nsh->ver_flags_len);

Rename ver_flags_len to ver_flags_ttl_len.

Do we need to consider new ttl key in this patch?

> +    ver_flags_len = ntohs(nsh->ver_flags_ttl_len);
>      version = (ver_flags_len & NSH_VER_MASK) >> NSH_VER_SHIFT;
>      flags = (ver_flags_len & NSH_FLAGS_MASK) >> NSH_FLAGS_SHIFT;
>  
> diff --git a/lib/odp-execute.c b/lib/odp-execute.c
> index 5f4d23a91a3e..d5542bde8b02 100644
> --- a/lib/odp-execute.c
> +++ b/lib/odp-execute.c
> @@ -279,8 +279,8 @@ odp_set_nsh(struct dp_packet *packet, const struct ovs_key_nsh *key,
>      struct nsh_hdr *nsh = dp_packet_l3(packet);
>  
>      if (!mask) {
> -        nsh->ver_flags_len = htons(key->flags << NSH_FLAGS_SHIFT) |
> -                             (nsh->ver_flags_len & ~htons(NSH_FLAGS_MASK));
> +        nsh->ver_flags_ttl_len = htons(key->flags << NSH_FLAGS_SHIFT) |
> +            (nsh->ver_flags_ttl_len & ~htons(NSH_FLAGS_MASK));
>          put_16aligned_be32(&nsh->path_hdr, key->path_hdr);
>          switch (nsh->md_type) {
>              case NSH_M_TYPE1:
> @@ -294,11 +294,11 @@ odp_set_nsh(struct dp_packet *packet, const struct ovs_key_nsh *key,
>                  break;
>          }
>      } else {
> -        uint8_t flags = (ntohs(nsh->ver_flags_len) & NSH_FLAGS_MASK) >>
> +        uint8_t flags = (ntohs(nsh->ver_flags_ttl_len) & NSH_FLAGS_MASK) >>
>                              NSH_FLAGS_SHIFT;
>          flags = key->flags | (flags & ~mask->flags);
> -        nsh->ver_flags_len = htons(flags << NSH_FLAGS_SHIFT) |
> -                             (nsh->ver_flags_len & ~htons(NSH_FLAGS_MASK));
> +        nsh->ver_flags_ttl_len = htons(flags << NSH_FLAGS_SHIFT) |
> +            (nsh->ver_flags_ttl_len & ~htons(NSH_FLAGS_MASK));
>  
>          ovs_be32 path_hdr = get_16aligned_be32(&nsh->path_hdr);
>          path_hdr = key->path_hdr | (path_hdr & ~mask->path_hdr);
> diff --git a/lib/packets.c b/lib/packets.c
> index 74d87eda89e1..a26b6c33e41c 100644
> --- a/lib/packets.c
> +++ b/lib/packets.c
> @@ -427,7 +427,9 @@ encap_nsh(struct dp_packet *packet, const struct ovs_action_encap_nsh *encap)
>      }
>  
>      nsh = (struct nsh_hdr *) dp_packet_push_uninit(packet, length);
> -    nsh->ver_flags_len = htons(encap->flags << NSH_FLAGS_SHIFT | length >> 2);
> +    nsh->ver_flags_ttl_len = htons((encap->flags << NSH_FLAGS_SHIFT)
> +                                   | (63 << NSH_TTL_SHIFT)
> +                                   | ((length >> 2) << NSH_LEN_SHIFT));
>      nsh->next_proto = next_proto;
>      put_16aligned_be32(&nsh->path_hdr, encap->path_hdr);
>      nsh->md_type = encap->mdtype;
> -- 
> 2.10.2
>