nxm_read_field_bits() simplifies reading of NXM fields with an
ofs_nbits parameter. This patch updates nxm_execute_reg_move() to
use the new function. A user outside of the nx-match module will
be added in future patches.
This patch also fixes a bug introduced in Commit 43edca57
"nx-match: New helpers.", which caused the "move" action to
improperly handle bit ranges.
---
lib/nx-match.c | 35 +++++++++++++++++++++++++----------
lib/nx-match.h | 3 +++
2 files changed, 28 insertions(+), 10 deletions(-)
diff --git a/lib/nx-match.c b/lib/nx-match.c
index 9fd00eb..ffb2474 100644
--- a/lib/nx-match.c
+++ b/lib/nx-match.c
@@ -1367,6 +1367,23 @@ nxm_read_field(const struct nxm_field *src, const struct
flow *flow)
NOT_REACHED();
}
+/* Returns the value of the NXM field corresponding to 'header' at 'ofs_nbits'
+ * in 'flow'. */
+uint64_t
+nxm_read_field_bits(ovs_be32 header, ovs_be16 ofs_nbits,
+ const struct flow *flow)
+{
+ int n_bits = nxm_decode_n_bits(ofs_nbits);
+ int ofs = nxm_decode_ofs(ofs_nbits);
+ uint64_t mask, data;
+
+ mask = n_bits == 64 ? UINT64_MAX : (UINT64_C(1) << n_bits) - 1;
+ data = nxm_read_field(nxm_field_lookup(ntohl(header)), flow);
+ data = (data >> ofs) & mask;
+
+ return data;
+}
+
static void
nxm_write_field(const struct nxm_field *dst, struct flow *flow,
uint64_t new_value)
@@ -1466,18 +1483,16 @@ void
nxm_execute_reg_move(const struct nx_action_reg_move *action,
struct flow *flow)
{
- /* Preparation. */
- int n_bits = ntohs(action->n_bits);
- uint64_t mask = n_bits == 64 ? UINT64_MAX : (UINT64_C(1) << n_bits) - 1;
+ ovs_be16 src_ofs_nbits, dst_ofs_nbits;
+ uint64_t src_data;
+ int n_bits;
- /* Get the interesting bits of the source field. */
- const struct nxm_field *src = nxm_field_lookup(ntohl(action->src));
- int src_ofs = ntohs(action->src_ofs);
- uint64_t src_data = nxm_read_field(src, flow) & (mask << src_ofs);
+ n_bits = ntohs(action->n_bits);
+ src_ofs_nbits = nxm_encode_ofs_nbits(ntohs(action->src_ofs), n_bits);
+ dst_ofs_nbits = nxm_encode_ofs_nbits(ntohs(action->dst_ofs), n_bits);
- nxm_reg_load(action->dst,
- nxm_encode_ofs_nbits(ntohs(action->dst_ofs), n_bits),
- src_data, flow);
+ src_data = nxm_read_field_bits(action->src, src_ofs_nbits, flow);
+ nxm_reg_load(action->dst, dst_ofs_nbits, src_data, flow);
}
void
diff --git a/lib/nx-match.h b/lib/nx-match.h
index a7441d0..04da239 100644
--- a/lib/nx-match.h
+++ b/lib/nx-match.h
@@ -41,6 +41,9 @@ int nx_put_match(struct ofpbuf *, const struct cls_rule *);
char *nx_match_to_string(const uint8_t *, unsigned int match_len);
int nx_match_from_string(const char *, struct ofpbuf *);
+uint64_t nxm_read_field_bits(ovs_be32 header, ovs_be16 ofs_nbits,
+ const struct flow *);
+
void nxm_parse_reg_move(struct nx_action_reg_move *, const char *);
void nxm_parse_reg_load(struct nx_action_reg_load *, const char *);
--
1.7.6
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