[ovs-dev] Query related to OF1.4 Group and Meter change notification

[niti Rohilla]

Hi Ben,

We are implementing Group and meter change notification messages(EXT-235).

As per the specification, the structure of Request forward message is:-
struct ofp_requestforward_header {
    struct ofp_header header;  /* Type OFPT_REQUESTFORWARD. */
    struct ofp_header request; /* Request being forwarded. */
};
OFP_ASSERT(sizeof(struct ofp_requestforward_header) == 16);

Please clarify what will be the contents of the 'request' ofp_header.
'request' will contain only the "group_mod" or "meter_mod" request
ofp_header or complete "group_mod" or "meter_mod" request i.e. this
complete structure

struct ofp_group_mod {
    struct ofp_header header;
    uint16_t command;     /* One of OFPGC_*. */
    uint8_t type;         /* One of OFPGT_*. */
    uint8_t pad;          /* Pad to 64 bits. */
    uint32_t group_id;    /* Group identifier. */
    struct ofp_bucket buckets[0]; /* The length of the bucket array is
inferred from the length field in the header. */
};
OFP_ASSERT(sizeof(struct ofp_group_mod) == 16);


If I send only the "group/meter_mod" request ofp_header then the
controllers receiving the request forward message won't be able to identify
which group/meter tables are changed at switch.

Whereas if I include the header+data part of "group/meter_mod" request then
the size of packet will become 24 bytes (requestforward ofp_header (8
bytes) + ofp_group_mod (16 bytes)) which is against the size of
ofp_requestforward_header mentioned in specification(16 bytes).

Please suggest what should be included in 'request' in the request forward
message.

Thanks
Niti Rohilla