Mercurial > hg > nginx-quic
view src/http/modules/ngx_http_upstream_ip_hash_module.c @ 6133:af7eba90645d
Win32: shared memory base addresses and remapping.
Two mechanisms are implemented to make it possible to store pointers
in shared memory on Windows, in particular on Windows Vista and later
versions with ASLR:
- The ngx_shm_remap() function added to allow remapping of a shared memory
zone to the address originally used for it in the master process. While
important, it doesn't solve the problem by itself as in many cases it's
not possible to use the address because of conflicts with other
allocations.
- We now create mappings at the same address in all processes by starting
mappings at predefined addresses normally unused by newborn processes.
These two mechanisms combined allow to use shared memory on Windows
almost without problems, including reloads.
Based on the patch by Sergey Brester:
http://mailman.nginx.org/pipermail/nginx-devel/2015-April/006836.html
author | Maxim Dounin <mdounin@mdounin.ru> |
---|---|
date | Mon, 27 Apr 2015 18:25:42 +0300 |
parents | b6047abf5f30 |
children | f01ab2dbcfdc |
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/* * Copyright (C) Igor Sysoev * Copyright (C) Nginx, Inc. */ #include <ngx_config.h> #include <ngx_core.h> #include <ngx_http.h> typedef struct { /* the round robin data must be first */ ngx_http_upstream_rr_peer_data_t rrp; ngx_uint_t hash; u_char addrlen; u_char *addr; u_char tries; ngx_event_get_peer_pt get_rr_peer; } ngx_http_upstream_ip_hash_peer_data_t; static ngx_int_t ngx_http_upstream_init_ip_hash_peer(ngx_http_request_t *r, ngx_http_upstream_srv_conf_t *us); static ngx_int_t ngx_http_upstream_get_ip_hash_peer(ngx_peer_connection_t *pc, void *data); static char *ngx_http_upstream_ip_hash(ngx_conf_t *cf, ngx_command_t *cmd, void *conf); static ngx_command_t ngx_http_upstream_ip_hash_commands[] = { { ngx_string("ip_hash"), NGX_HTTP_UPS_CONF|NGX_CONF_NOARGS, ngx_http_upstream_ip_hash, 0, 0, NULL }, ngx_null_command }; static ngx_http_module_t ngx_http_upstream_ip_hash_module_ctx = { NULL, /* preconfiguration */ NULL, /* postconfiguration */ NULL, /* create main configuration */ NULL, /* init main configuration */ NULL, /* create server configuration */ NULL, /* merge server configuration */ NULL, /* create location configuration */ NULL /* merge location configuration */ }; ngx_module_t ngx_http_upstream_ip_hash_module = { NGX_MODULE_V1, &ngx_http_upstream_ip_hash_module_ctx, /* module context */ ngx_http_upstream_ip_hash_commands, /* module directives */ NGX_HTTP_MODULE, /* module type */ NULL, /* init master */ NULL, /* init module */ NULL, /* init process */ NULL, /* init thread */ NULL, /* exit thread */ NULL, /* exit process */ NULL, /* exit master */ NGX_MODULE_V1_PADDING }; static u_char ngx_http_upstream_ip_hash_pseudo_addr[3]; static ngx_int_t ngx_http_upstream_init_ip_hash(ngx_conf_t *cf, ngx_http_upstream_srv_conf_t *us) { if (ngx_http_upstream_init_round_robin(cf, us) != NGX_OK) { return NGX_ERROR; } us->peer.init = ngx_http_upstream_init_ip_hash_peer; return NGX_OK; } static ngx_int_t ngx_http_upstream_init_ip_hash_peer(ngx_http_request_t *r, ngx_http_upstream_srv_conf_t *us) { struct sockaddr_in *sin; #if (NGX_HAVE_INET6) struct sockaddr_in6 *sin6; #endif ngx_http_upstream_ip_hash_peer_data_t *iphp; iphp = ngx_palloc(r->pool, sizeof(ngx_http_upstream_ip_hash_peer_data_t)); if (iphp == NULL) { return NGX_ERROR; } r->upstream->peer.data = &iphp->rrp; if (ngx_http_upstream_init_round_robin_peer(r, us) != NGX_OK) { return NGX_ERROR; } r->upstream->peer.get = ngx_http_upstream_get_ip_hash_peer; switch (r->connection->sockaddr->sa_family) { case AF_INET: sin = (struct sockaddr_in *) r->connection->sockaddr; iphp->addr = (u_char *) &sin->sin_addr.s_addr; iphp->addrlen = 3; break; #if (NGX_HAVE_INET6) case AF_INET6: sin6 = (struct sockaddr_in6 *) r->connection->sockaddr; iphp->addr = (u_char *) &sin6->sin6_addr.s6_addr; iphp->addrlen = 16; break; #endif default: iphp->addr = ngx_http_upstream_ip_hash_pseudo_addr; iphp->addrlen = 3; } iphp->hash = 89; iphp->tries = 0; iphp->get_rr_peer = ngx_http_upstream_get_round_robin_peer; return NGX_OK; } static ngx_int_t ngx_http_upstream_get_ip_hash_peer(ngx_peer_connection_t *pc, void *data) { ngx_http_upstream_ip_hash_peer_data_t *iphp = data; time_t now; ngx_int_t w; uintptr_t m; ngx_uint_t i, n, p, hash; ngx_http_upstream_rr_peer_t *peer; ngx_log_debug1(NGX_LOG_DEBUG_HTTP, pc->log, 0, "get ip hash peer, try: %ui", pc->tries); /* TODO: cached */ ngx_http_upstream_rr_peers_wlock(iphp->rrp.peers); if (iphp->tries > 20 || iphp->rrp.peers->single) { ngx_http_upstream_rr_peers_unlock(iphp->rrp.peers); return iphp->get_rr_peer(pc, &iphp->rrp); } now = ngx_time(); pc->cached = 0; pc->connection = NULL; hash = iphp->hash; for ( ;; ) { for (i = 0; i < (ngx_uint_t) iphp->addrlen; i++) { hash = (hash * 113 + iphp->addr[i]) % 6271; } w = hash % iphp->rrp.peers->total_weight; peer = iphp->rrp.peers->peer; p = 0; while (w >= peer->weight) { w -= peer->weight; peer = peer->next; p++; } n = p / (8 * sizeof(uintptr_t)); m = (uintptr_t) 1 << p % (8 * sizeof(uintptr_t)); if (iphp->rrp.tried[n] & m) { goto next; } ngx_log_debug2(NGX_LOG_DEBUG_HTTP, pc->log, 0, "get ip hash peer, hash: %ui %04XA", p, m); if (peer->down) { goto next; } if (peer->max_fails && peer->fails >= peer->max_fails && now - peer->checked <= peer->fail_timeout) { goto next; } break; next: if (++iphp->tries > 20) { ngx_http_upstream_rr_peers_unlock(iphp->rrp.peers); return iphp->get_rr_peer(pc, &iphp->rrp); } } iphp->rrp.current = peer; pc->sockaddr = peer->sockaddr; pc->socklen = peer->socklen; pc->name = &peer->name; peer->conns++; if (now - peer->checked > peer->fail_timeout) { peer->checked = now; } ngx_http_upstream_rr_peers_unlock(iphp->rrp.peers); iphp->rrp.tried[n] |= m; iphp->hash = hash; return NGX_OK; } static char * ngx_http_upstream_ip_hash(ngx_conf_t *cf, ngx_command_t *cmd, void *conf) { ngx_http_upstream_srv_conf_t *uscf; uscf = ngx_http_conf_get_module_srv_conf(cf, ngx_http_upstream_module); if (uscf->peer.init_upstream) { ngx_conf_log_error(NGX_LOG_WARN, cf, 0, "load balancing method redefined"); } uscf->peer.init_upstream = ngx_http_upstream_init_ip_hash; uscf->flags = NGX_HTTP_UPSTREAM_CREATE |NGX_HTTP_UPSTREAM_WEIGHT |NGX_HTTP_UPSTREAM_MAX_FAILS |NGX_HTTP_UPSTREAM_FAIL_TIMEOUT |NGX_HTTP_UPSTREAM_DOWN; return NGX_CONF_OK; }