[ovs-dev] [of1.1 draft v2 5/7] ofp-util: Add functions for working with OpenFlow 1.1 port numbers.

[Ben Pfaff]

OpenFlow 1.1 extends port numbers to 32 bits.  Initially we plan to support
only port numbers in the 16-bit range in Open vSwitch.  However the OF1.1
reserved ports have high-valued fixed numbers that require translation to
high fixed values in the 16-bit range for OF1.0.  These new functions
provide this translation.

Nothing uses these functions yet.

These new functions need comments before they're ready.
---
 lib/ofp-util.c |   24 ++++++++++++++++++++++++
 lib/ofp-util.h |    3 +++
 2 files changed, 27 insertions(+), 0 deletions(-)

diff --git a/lib/ofp-util.c b/lib/ofp-util.c
index 1257e6f..a4d13cc 100644
--- a/lib/ofp-util.c
+++ b/lib/ofp-util.c
@@ -2591,6 +2591,30 @@ ofputil_frag_handling_from_string(const char *s, enum ofp_config_flags *flags)
     return true;
 }
 
+enum ofperr
+ofputil_port_from_ofp11(ovs_be32 ofp11_port, uint16_t *ofp10_port)
+{
+    uint32_t ofp11_port_h = ntohl(ofp11_port);
+
+    if (ofp11_port_h < OFPP_MAX) {
+        *ofp10_port = ofp11_port_h;
+        return 0;
+    } else if (ofp11_port_h >= 0xfffffff8) {
+        *ofp10_port = ofp11_port_h >> 16;
+        return 0;
+    } else {
+        VLOG_WARN_RL(&bad_ofmsg_rl, "port %"PRIu32" is outside the supported "
+                     "range 0 through %d", ofp11_port_h, OFPP_MAX - 1);
+        return OFPERR_OFPBAC_BAD_OUT_PORT;
+    }
+}
+
+ovs_be32
+ofputil_port_to_ofp11(uint16_t ofp10_port)
+{
+    return htonl(ofp10_port < OFPP_MAX ? ofp10_port : ofp10_port + 0xffff0000);
+}
+
 /* Checks that 'port' is a valid output port for the OFPAT_OUTPUT action, given
  * that the switch will never have more than 'max_ports' ports.  Returns 0 if
  * 'port' is valid, otherwise an OpenFlow return code. */
diff --git a/lib/ofp-util.h b/lib/ofp-util.h
index 5991594..3422ece 100644
--- a/lib/ofp-util.h
+++ b/lib/ofp-util.h
@@ -99,6 +99,9 @@ enum ofputil_msg_code ofputil_msg_type_code(const struct ofputil_msg_type *);
 const char *ofputil_msg_type_name(const struct ofputil_msg_type *);
 
 /* Port numbers. */
+enum ofperr ofputil_port_from_ofp11(ovs_be32 ofp11_port, uint16_t *ofp10_port);
+ovs_be32 ofputil_port_to_ofp11(uint16_t ofp10_port);
+
 enum ofperr ofputil_check_output_port(uint16_t ofp_port, int max_ports);
 bool ofputil_port_from_string(const char *, uint16_t *port);
 void ofputil_format_port(uint16_t port, struct ds *);
-- 
1.7.2.5