Hi Jason,
Very good proposal. From my point of view, these APIs are reasonable and
adequate. Now FCoE code can concentrate on DCBX state machines and does
not need to care about LLDP details.
Please let me know when you have a prototype of this.
Thanks & Regards,
Zhong
Jason King wrote:
Here's what I'm thinking for LLDP hooks for DCBX. Any feedback would
be appreciated.
I'm assuming that at some point there will be an in-kernel API that
uses mblk_t that can be used for PDU tx/rx (and thus this will depend
on such an API appearing).
The idea is that the logic for DCBX will reside separate from LLDP
itself, with LLDP merely providing hooks to allow DCBX to send/recv
TLVs for each link as needed. That way LLDP doesn't need to know a
lot about the FCoE code.
/*
* Called for each DCBX tlv that is received.
* data - A DCBX private data structure, set by lldp_dcbx_start().
If the remote end is initiating, this may be NULL.
* m - The message block. b_rptr will point to the start of
the DCBX TLV data. I.e. the type, len, oui, and oui type fields are
already consumed.
* len - The length of the TLV (excluding the oui & oui type fields).
*
* The callback is expected in all circumstances to advance b_rptr to
the start of the next TLV (or end of PDU).
* Return:
* B_TRUE - TLV was formed correctly.
* B_FALSE - TLV was malformed. The rx_tlv_discarded counter is
incremented. Processing continues with the next TLV.
*/
typedef boolean_t (*lldp_dcbx_rx_t)(void * data, mblk_t *m, size_t len);
/*
* Called whenever a link has been enabled for DCBX via
lldp_dcbx_start() and a PDU is in the process of being constructed for
TX.
* Callback is expected to append DCBX TLVs to b_wptr.
* data - A DCBX private data structure as set by lldp_dcbx_start.
* m - The mblk_t to append to.
* Return:
* B_TRUE - TLVs were added successfully.
* B_FALSE - insufficient room to add all TLVs. Used to signal no
additional TLVs (except END TLV) should be appended. b_wptr should
point
* to the end of the last sucessfully added TLV.
*/
typedef boolean_t (*lldp_dcbx_tx_t)(void *data, mblk_t *m);
/*
* Not specific to DCBX, but probably useful:
*
* Append TLV header of type t_type and length t_len to m.
* m - The mblk_t to append to
* t_type - The TLV type. For DCBX, this will be LLDP_T_ORG_SPECIFIC.
* t_len - The TLV length, for DCBX, this should include the 4 byte
org specific header.
* reserve_end - If space for the end TLV should be reserved in the
TLV. This will always be set to B_TRUE for DCBX.
*
* Return:
* B_TRUE - Header appended and sufficient space remains in mblk_t
for t_len data (including space for END TLV if reserve_end is set).
* B_FALSE - Insufficient space remains in the mblk_t, the header was
not appended. Further additions of TLVs should be aborted.
*/
boolean_t lldp_make_tlv_header(mblk_t *m, uint16_t t_type, uint16_t
t_len, boolean_t reserve_end);
/* Register callbacks to LLDP */
void lldp_dcbx_init(lldp_dcbx_tx_t, lldp_dcbx_rx_t);
/* Remove callbacks from LLDP */
void lldp_dcbx_fini(void);
/*
* Enable DCBX on linkname. This causes a number of events to occur:
* - Fast start is enabled on the interface.
* - Whenever a PDU is being generated for the link, the registered
callback will be invoked
* linkname - The name of the link
* data - DCBX private data, will be passed to callback
functions when invoked
*
* Return:
* 0 - Success
* ENOENT - Link does not exist
* EINVAL - Link is not enabled for LLDP.
*/
int lldp_dcbx_start(const char *linkname, void *data);
/*
* Disable DCBX on linkname. Callbacks will no longer be invoked
*/
void lldp_dcbx_stop(const char *linkname);
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