Mercurial > hg > nginx-quic
view src/os/unix/ngx_sunpro_atomic_sparc64.h @ 7386:9200b41db765 stable-1.14
HTTP/2: limit the number of idle state switches.
An attack that continuously switches HTTP/2 connection between
idle and active states can result in excessive CPU usage.
This is because when a connection switches to the idle state,
all of its memory pool caches are freed.
This change limits the maximum allowed number of idle state
switches to 10 * http2_max_requests (i.e., 10000 by default).
This limits possible CPU usage in one connection, and also
imposes a limit on the maximum lifetime of a connection.
Initially reported by Gal Goldshtein from F5 Networks.
author | Ruslan Ermilov <ru@nginx.com> |
---|---|
date | Tue, 06 Nov 2018 16:29:49 +0300 |
parents | d620f497c50f |
children |
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/* * Copyright (C) Igor Sysoev * Copyright (C) Nginx, Inc. */ #if (NGX_PTR_SIZE == 4) #define NGX_CASA ngx_casa #else #define NGX_CASA ngx_casxa #endif ngx_atomic_uint_t ngx_casa(ngx_atomic_uint_t set, ngx_atomic_uint_t old, ngx_atomic_t *lock); ngx_atomic_uint_t ngx_casxa(ngx_atomic_uint_t set, ngx_atomic_uint_t old, ngx_atomic_t *lock); /* the code in src/os/unix/ngx_sunpro_sparc64.il */ static ngx_inline ngx_atomic_uint_t ngx_atomic_cmp_set(ngx_atomic_t *lock, ngx_atomic_uint_t old, ngx_atomic_uint_t set) { set = NGX_CASA(set, old, lock); return (set == old); } static ngx_inline ngx_atomic_int_t ngx_atomic_fetch_add(ngx_atomic_t *value, ngx_atomic_int_t add) { ngx_atomic_uint_t old, res; old = *value; for ( ;; ) { res = old + add; res = NGX_CASA(res, old, value); if (res == old) { return res; } old = res; } } #define ngx_memory_barrier() \ __asm (".volatile"); \ __asm ("membar #LoadLoad | #LoadStore | #StoreStore | #StoreLoad"); \ __asm (".nonvolatile") #define ngx_cpu_pause()