Mercurial > hg > nginx
view src/core/ngx_crc32.h @ 8078:5244d3b165ff
SSL: single allocation in session cache on 32-bit platforms.
Given the present typical SSL session sizes, on 32-bit platforms it is
now beneficial to store all data in a single allocation, since rbtree
node + session id + ASN1 representation of a session takes 256 bytes of
shared memory (36 + 32 + 150 = about 218 bytes plus SNI server name).
Storing all data in a single allocation is beneficial for SNI names up to
about 40 characters long and makes it possible to store about 4000 sessions
in one megabyte (instead of about 3000 sessions now). This also slightly
simplifies the code.
author | Maxim Dounin <mdounin@mdounin.ru> |
---|---|
date | Wed, 12 Oct 2022 20:14:40 +0300 |
parents | d620f497c50f |
children |
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/* * Copyright (C) Igor Sysoev * Copyright (C) Nginx, Inc. */ #ifndef _NGX_CRC32_H_INCLUDED_ #define _NGX_CRC32_H_INCLUDED_ #include <ngx_config.h> #include <ngx_core.h> extern uint32_t *ngx_crc32_table_short; extern uint32_t ngx_crc32_table256[]; static ngx_inline uint32_t ngx_crc32_short(u_char *p, size_t len) { u_char c; uint32_t crc; crc = 0xffffffff; while (len--) { c = *p++; crc = ngx_crc32_table_short[(crc ^ (c & 0xf)) & 0xf] ^ (crc >> 4); crc = ngx_crc32_table_short[(crc ^ (c >> 4)) & 0xf] ^ (crc >> 4); } return crc ^ 0xffffffff; } static ngx_inline uint32_t ngx_crc32_long(u_char *p, size_t len) { uint32_t crc; crc = 0xffffffff; while (len--) { crc = ngx_crc32_table256[(crc ^ *p++) & 0xff] ^ (crc >> 8); } return crc ^ 0xffffffff; } #define ngx_crc32_init(crc) \ crc = 0xffffffff static ngx_inline void ngx_crc32_update(uint32_t *crc, u_char *p, size_t len) { uint32_t c; c = *crc; while (len--) { c = ngx_crc32_table256[(c ^ *p++) & 0xff] ^ (c >> 8); } *crc = c; } #define ngx_crc32_final(crc) \ crc ^= 0xffffffff ngx_int_t ngx_crc32_table_init(void); #endif /* _NGX_CRC32_H_INCLUDED_ */