view src/core/ngx_resolver.h @ 6153:4f6efabcb09b

The "reuseport" option of the "listen" directive. When configured, an individual listen socket on a given address is created for each worker process. This allows to reduce in-kernel lock contention on configurations with high accept rates, resulting in better performance. As of now it works on Linux and DragonFly BSD. Note that on Linux incoming connection requests are currently tied up to a specific listen socket, and if some sockets are closed, connection requests will be reset, see https://lwn.net/Articles/542629/. With nginx, this may happen if the number of worker processes is reduced. There is no such problem on DragonFly BSD. Based on previous work by Sepherosa Ziehau and Yingqi Lu.
author Maxim Dounin <mdounin@mdounin.ru>
date Wed, 20 May 2015 15:51:56 +0300
parents 5004210e8c78
children 7316c57e4fe7
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/*
 * Copyright (C) Igor Sysoev
 * Copyright (C) Nginx, Inc.
 */


#include <ngx_config.h>
#include <ngx_core.h>


#ifndef _NGX_RESOLVER_H_INCLUDED_
#define _NGX_RESOLVER_H_INCLUDED_


#define NGX_RESOLVE_A         1
#define NGX_RESOLVE_CNAME     5
#define NGX_RESOLVE_PTR       12
#define NGX_RESOLVE_MX        15
#define NGX_RESOLVE_TXT       16
#if (NGX_HAVE_INET6)
#define NGX_RESOLVE_AAAA      28
#endif
#define NGX_RESOLVE_DNAME     39

#define NGX_RESOLVE_FORMERR   1
#define NGX_RESOLVE_SERVFAIL  2
#define NGX_RESOLVE_NXDOMAIN  3
#define NGX_RESOLVE_NOTIMP    4
#define NGX_RESOLVE_REFUSED   5
#define NGX_RESOLVE_TIMEDOUT  NGX_ETIMEDOUT


#define NGX_NO_RESOLVER       (void *) -1

#define NGX_RESOLVER_MAX_RECURSION    50


typedef struct {
    ngx_connection_t         *connection;
    struct sockaddr          *sockaddr;
    socklen_t                 socklen;
    ngx_str_t                 server;
    ngx_log_t                 log;
} ngx_udp_connection_t;


typedef struct ngx_resolver_ctx_s  ngx_resolver_ctx_t;

typedef void (*ngx_resolver_handler_pt)(ngx_resolver_ctx_t *ctx);


typedef struct {
    /* PTR: resolved name, A: name to resolve */
    u_char                   *name;

    ngx_queue_t               queue;

    /* event ident must be after 3 pointers as in ngx_connection_t */
    ngx_int_t                 ident;

    ngx_rbtree_node_t         node;

#if (NGX_HAVE_INET6)
    /* PTR: IPv6 address to resolve (IPv4 address is in rbtree node key) */
    struct in6_addr           addr6;
#endif

    u_short                   nlen;
    u_short                   qlen;

    u_char                   *query;
#if (NGX_HAVE_INET6)
    u_char                   *query6;
#endif

    union {
        in_addr_t             addr;
        in_addr_t            *addrs;
        u_char               *cname;
    } u;

    u_char                    code;
    u_short                   naddrs;
    u_short                   cnlen;

#if (NGX_HAVE_INET6)
    union {
        struct in6_addr       addr6;
        struct in6_addr      *addrs6;
    } u6;

    u_short                   naddrs6;
#endif

    time_t                    expire;
    time_t                    valid;
    uint32_t                  ttl;

    ngx_resolver_ctx_t       *waiting;
} ngx_resolver_node_t;


typedef struct {
    /* has to be pointer because of "incomplete type" */
    ngx_event_t              *event;
    void                     *dummy;
    ngx_log_t                *log;

    /* event ident must be after 3 pointers as in ngx_connection_t */
    ngx_int_t                 ident;

    /* simple round robin DNS peers balancer */
    ngx_array_t               udp_connections;
    ngx_uint_t                last_connection;

    ngx_rbtree_t              name_rbtree;
    ngx_rbtree_node_t         name_sentinel;

    ngx_rbtree_t              addr_rbtree;
    ngx_rbtree_node_t         addr_sentinel;

    ngx_queue_t               name_resend_queue;
    ngx_queue_t               addr_resend_queue;

    ngx_queue_t               name_expire_queue;
    ngx_queue_t               addr_expire_queue;

#if (NGX_HAVE_INET6)
    ngx_uint_t                ipv6;                 /* unsigned  ipv6:1; */
    ngx_rbtree_t              addr6_rbtree;
    ngx_rbtree_node_t         addr6_sentinel;
    ngx_queue_t               addr6_resend_queue;
    ngx_queue_t               addr6_expire_queue;
#endif

    time_t                    resend_timeout;
    time_t                    expire;
    time_t                    valid;

    ngx_uint_t                log_level;
} ngx_resolver_t;


struct ngx_resolver_ctx_s {
    ngx_resolver_ctx_t       *next;
    ngx_resolver_t           *resolver;
    ngx_udp_connection_t     *udp_connection;

    ngx_int_t                 state;
    ngx_str_t                 name;

    ngx_uint_t                naddrs;
    ngx_addr_t               *addrs;
    ngx_addr_t                addr;
    struct sockaddr_in        sin;

    ngx_resolver_handler_pt   handler;
    void                     *data;
    ngx_msec_t                timeout;

    ngx_uint_t                quick;  /* unsigned  quick:1; */
    ngx_uint_t                recursion;
    ngx_event_t              *event;
};


ngx_resolver_t *ngx_resolver_create(ngx_conf_t *cf, ngx_str_t *names,
    ngx_uint_t n);
ngx_resolver_ctx_t *ngx_resolve_start(ngx_resolver_t *r,
    ngx_resolver_ctx_t *temp);
ngx_int_t ngx_resolve_name(ngx_resolver_ctx_t *ctx);
void ngx_resolve_name_done(ngx_resolver_ctx_t *ctx);
ngx_int_t ngx_resolve_addr(ngx_resolver_ctx_t *ctx);
void ngx_resolve_addr_done(ngx_resolver_ctx_t *ctx);
char *ngx_resolver_strerror(ngx_int_t err);


#endif /* _NGX_RESOLVER_H_INCLUDED_ */