[ovs-dev] [multipath 3/7] nx-match: New helper functions for working with ofs_nbits in NXM actions.

Justin Pettit jpettit at nicira.com
Fri Dec 17 18:30:38 UTC 2010


Looks good.

--Justin


On Dec 16, 2010, at 2:42 PM, Ben Pfaff wrote:

> ---
> lib/nx-match.c |   15 +++++++--------
> lib/nx-match.h |   24 ++++++++++++++++++++++++
> 2 files changed, 31 insertions(+), 8 deletions(-)
> 
> diff --git a/lib/nx-match.c b/lib/nx-match.c
> index 0b87fc9..92d3b9e 100644
> --- a/lib/nx-match.c
> +++ b/lib/nx-match.c
> @@ -939,7 +939,7 @@ nxm_parse_reg_load(struct nx_action_reg_load *load, const char *s)
>     load->len = htons(sizeof *load);
>     load->vendor = htonl(NX_VENDOR_ID);
>     load->subtype = htons(NXAST_REG_LOAD);
> -    load->ofs_nbits = htons((ofs << 6) | (n_bits - 1));
> +    load->ofs_nbits = nxm_encode_ofs_nbits(ofs, n_bits);
>     load->dst = htonl(dst);
>     load->value = htonll(value);
> }
> @@ -975,9 +975,8 @@ nxm_format_reg_move(const struct nx_action_reg_move *move, struct ds *s)
> void
> nxm_format_reg_load(const struct nx_action_reg_load *load, struct ds *s)
> {
> -    uint16_t ofs_nbits = ntohs(load->ofs_nbits);
> -    int ofs = ofs_nbits >> 6;
> -    int n_bits = (ofs_nbits & 0x3f) + 1;
> +    int ofs = nxm_decode_ofs(load->ofs_nbits);
> +    int n_bits = nxm_decode_n_bits(load->ofs_nbits);
>     uint32_t dst = ntohl(load->dst);
>     uint64_t value = ntohll(load->value);
> 
> @@ -1031,8 +1030,8 @@ nxm_check_reg_load(const struct nx_action_reg_load *action,
>     const struct nxm_field *dst;
>     int ofs, n_bits;
> 
> -    ofs = ntohs(action->ofs_nbits) >> 6;
> -    n_bits = (ntohs(action->ofs_nbits) & 0x3f) + 1;
> +    ofs = nxm_decode_ofs(action->ofs_nbits);
> +    n_bits = nxm_decode_n_bits(action->ofs_nbits);
>     dst = nxm_field_lookup(ntohl(action->dst));
>     if (!field_ok(dst, flow, ofs + n_bits)) {
>         return BAD_ARGUMENT;
> @@ -1175,7 +1174,7 @@ nxm_execute_reg_load(const struct nx_action_reg_load *action,
>                      struct flow *flow)
> {
>     /* Preparation. */
> -    int n_bits = (ntohs(action->ofs_nbits) & 0x3f) + 1;
> +    int n_bits = nxm_decode_n_bits(action->ofs_nbits);
>     uint32_t mask = n_bits == 32 ? UINT32_MAX : (UINT32_C(1) << n_bits) - 1;
>     uint32_t *reg = &flow->regs[NXM_NX_REG_IDX(ntohl(action->dst))];
> 
> @@ -1183,7 +1182,7 @@ nxm_execute_reg_load(const struct nx_action_reg_load *action,
>     uint32_t src_data = ntohll(action->value);
> 
>     /* Get remaining bits of the destination field. */
> -    int dst_ofs = ntohs(action->ofs_nbits) >> 6;
> +    int dst_ofs = nxm_decode_ofs(action->ofs_nbits);
>     uint32_t dst_data = *reg & ~(mask << dst_ofs);
> 
>     *reg = dst_data | (src_data << dst_ofs);
> diff --git a/lib/nx-match.h b/lib/nx-match.h
> index c790333..d0e1c65 100644
> --- a/lib/nx-match.h
> +++ b/lib/nx-match.h
> @@ -18,6 +18,9 @@
> #define NX_MATCH_H 1
> 
> #include <stdint.h>
> +#include <sys/types.h>
> +#include <netinet/in.h>
> +#include "openvswitch/types.h"
> 
> struct cls_rule;
> struct ds;
> @@ -50,6 +53,27 @@ int nxm_check_reg_load(const struct nx_action_reg_load *, const struct flow *);
> void nxm_execute_reg_move(const struct nx_action_reg_move *, struct flow *);
> void nxm_execute_reg_load(const struct nx_action_reg_load *, struct flow *);
> 
> +/* Dealing with the 'ofs_nbits' members of struct nx_action_reg_load and struct
> + * nx_action_multipath. */
> +
> +static inline ovs_be16
> +nxm_encode_ofs_nbits(int ofs, int n_bits)
> +{
> +    return htons((ofs << 6) | (n_bits - 1));
> +}
> +
> +static inline int
> +nxm_decode_ofs(ovs_be16 ofs_nbits)
> +{
> +    return ntohs(ofs_nbits) >> 6;
> +}
> +
> +static inline int
> +nxm_decode_n_bits(ovs_be16 ofs_nbits)
> +{
> +    return (ntohs(ofs_nbits) & 0x3f) + 1;
> +}
> +
> /* Upper bound on the length of an nx_match.  The longest nx_match (assuming
>  * we implement 4 registers) would be:
>  *
> -- 
> 1.7.1
> 
> 
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