LRU Cache

Detailed Description

Least Recently Used (LRU) cache is implemented using UT HASH. Instead of implementing complex timer framework with callbacks, LRU cache is used to check for various timeouts. LRU cache is walked backwards and entries checked if timeout occurred. For efficiency number of entries walked per vectorloop iteration is limited. Walk stops when either the limit is reached, or an entry encountered that has not timed out.

Author

Faruk Grozdanic

Copyright

Released under MIT license.

Copyright (c) 2025 Faruk Grozdanic

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the “Software”), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

Macros
#define	LRU_CACHE_ADD(head, add)    HASH_ADD(hh, head, cid, sizeof(uint64_t), add)
#define	LRU_CACHE_DEL(head, del)    HASH_DELETE(hh, head, del)

Macro Definition Documentation

LRU_CACHE_ADD

#define LRU_CACHE_ADD	(		head,
			add
	)		HASH_ADD(hh, head, cid, sizeof(uint64_t), add)

Macro to add entry to TCP connection LRU cache.

LRU_CACHE_DEL

#define LRU_CACHE_DEL	(		head,
			del
	)		HASH_DELETE(hh, head, del)

Macro to remove entry from TCP connection LRU cache.