protocol_port_range_dpo_t_ Struct Reference

The object that is in the data-path to perform the check. More...

Collaboration diagram for protocol_port_range_dpo_t_:

Data Fields
u16	n_used_blocks
	The number of blocks from the 'block' array below that have rnages configured. More...
u16	n_free_ranges
	The total number of free ranges from all blocks. More...
protocol_port_range_t	blocks [N_BLOCKS_PER_DPO]
	the fixed size array of ranges More...

Detailed Description

The object that is in the data-path to perform the check.

Some trade-offs here; memory vs performance.

performance: the principle factor is d-cache line misses/hits. so we want the data layout to minimise the d-cache misses. This means not following dependent reads. i.e. not doing

struct B { u16 n_ranges; range_t *ragnes; // vector of ranges. }

so to read ranges[0] we would first d-cache miss on the address of the object of type B, for which we would need to wait before we can get the address of B->ranges. So this layout is better:

struct B { u16 n_ranges; range_t ragnes[N]; }

memory: the latter layout above is more memory hungry. And N needs to be: 1 - sized for the maximum required 2 - fixed, so that objects of type B can be pool allocated and so 'get'-able using an index. An option over fixed might be to allocate contiguous chunk from the pool (like we used to do for multi-path adjs).

Definition at line 102 of file ip_source_and_port_range_check.h.

Field Documentation

protocol_port_range_t protocol_port_range_dpo_t_::blocks[N_BLOCKS_PER_DPO]

the fixed size array of ranges

Definition at line 120 of file ip_source_and_port_range_check.h.

u16 protocol_port_range_dpo_t_::n_free_ranges

The total number of free ranges from all blocks.

Used to prevent overrun of the ranges available.

Definition at line 115 of file ip_source_and_port_range_check.h.

u16 protocol_port_range_dpo_t_::n_used_blocks

The number of blocks from the 'block' array below that have rnages configured.

We keep this count so that in the data-path we can limit the loop to be only over the blocks we need

Definition at line 109 of file ip_source_and_port_range_check.h.

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The documentation for this struct was generated from the following file:

• src/vnet/ip/ip_source_and_port_range_check.h