nginx模块开发—HTTP初始化之listen

偏执的太偏执、 2022-04-18 05:44 189阅读 0赞

## 1、知识百科 ##

nginx作为一个高性能的HTTP服务器，网络的处理是其核心，了解网络的初始化有助于加深对nginx网络处理的了解。与网络有关的配置命令主要有两个：listen和sever\_name。listen命令设置nginx监听地址，对于IP协议，这个地址就是address和port，对于UNIX域套接字协议，这个地址就是path，一条listen指令只能指定一个address或者port，address也可以是主机名，比如：

listen 127.0.0.1:8000;
    
     listen 127.0.0.1;
    
    listen 8000;
    
     listen *:8000;
    
     listen localhost:8000;
    
     listen [::]:8000;
    
     listen [fe80::1];
    
     listen unix:/var/run/nginx.sock;

server\_name指令列出虚拟主机的所有主机名，如server\_name example.com \*.example.com www.example.\*，用空格分割。

## 2、数据结构 ##

### ngx\_http\_conf\_port\_t（ngx\_http\_core\_listen入口） ###

typedef struct {
    
        ngx_int_t                  family;
    
        in_port_t                  port;
    
        ngx_array_t                addrs;     /* array of ngx_http_conf_addr_t */
    
    } ngx_http_conf_port_t;

### ngx\_http\_conf\_addr\_t ###

typedef struct {
    
        ngx_http_listen_opt_t      opt;
    
        ngx_hash_t                 hash;
    
        ngx_hash_wildcard_t       *wc_head;
    
        ngx_hash_wildcard_t       *wc_tail;
    
    
    
        ngx_http_core_srv_conf_t  *default_server;
    
        ngx_array_t                servers;  /* array of ngx_http_core_srv_conf_t */
    
    } ngx_http_conf_addr_t;

### ngx\_http\_core\_srv\_conf\_t ###

typedef struct {
    
        /* array of the ngx_http_server_name_t, "server_name" directive */
    
        ngx_array_t                 server_names;
    
    
    
        /* server ctx */
    
        ngx_http_conf_ctx_t        *ctx;
    
    
    
        ngx_str_t                   server_name;
    
    
    
        size_t                      connection_pool_size;
    
        size_t                      request_pool_size;
    
        size_t                      client_header_buffer_size;
    
    
    
        ngx_bufs_t                  large_client_header_buffers;
    
    
    
        ngx_msec_t                  client_header_timeout;
    
    
    
        ngx_flag_t                  ignore_invalid_headers;
    
        ngx_flag_t                  merge_slashes;
    
        ngx_flag_t                  underscores_in_headers;
    
    
    
        unsigned                    listen:1;
    
    
    
        ngx_http_core_loc_conf_t  **named_locations;
    
    } ngx_http_core_srv_conf_t;

### ngx\_http\_listen\_opt\_t（重要） ###

typedef struct {
    
        union {
    
            struct sockaddr        sockaddr;
    
            struct sockaddr_in     sockaddr_in;
    
            u_char              sockaddr_data[NGX_SOCKADDRLEN];
    
        } u;
    
    
    
        socklen_t                  socklen;
    
    
    
        unsigned                   set:1;                       // bind/backlog/…
    
        unsigned                   default_server:1;  // default_server
    
        unsigned                   bind:1;                    // bind/backlog/…
    
        unsigned                   wildcard:1;
    
    #if (NGX_HTTP_SSL)
    
        unsigned                   ssl:1;
    
    #endif
    
    #if (NGX_HTTP_SPDY)
    
        unsigned                   spdy:1;                  // spdy
    
    #endif
    
        unsigned                   so_keepalive:2;
    
        unsigned                   proxy_protocol:1;   // proxy_protocol
    
    
    
        int                        backlog;   // backlog
    
        int                        rcvbuf;    // rcvbuf
    
        int                        sndbuf;    // sndbuf
    
        。。。
    
    
    
        u_char                     addr[NGX_SOCKADDR_STRLEN + 1];  // 0.0.0.0:8000
    
    } ngx_http_listen_opt_t;

### ngx\_listening\_s（ngx\_http\_init\_connection入口） ###

struct ngx_listening_s {
    
        ngx_socket_t        fd;
    
    
    
        struct sockaddr    *sockaddr;
    
        socklen_t           socklen;    /* size of sockaddr */
    
        size_t              addr_text_max_len;
    
        ngx_str_t           addr_text;
    
    
    
        int                 type;
    
    
    
        int                 backlog;
    
        int                 rcvbuf;
    
        int                 sndbuf;
    
    
    
        ngx_connection_handler_pt   handler;
    
    
    
        void               *servers;  /* array of ngx_http_port_t, for example */
    
        。。。
    
        ngx_listening_t    *previous;
    
        ngx_connection_t   *connection;
    
    
    
        unsigned            open:1;
    
        unsigned            remain:1;
    
        unsigned            ignore:1;
    
    
    
        unsigned            bound:1;       /* already bound */
    
        unsigned            inherited:1;   /* inherited from previous process */
    
        unsigned            nonblocking_accept:1;
    
        unsigned            listen:1;
    
        unsigned            nonblocking:1;
    
        unsigned            shared:1;    /* shared between threads or processes */
    
        unsigned            addr_ntop:1;
    
    
    
        unsigned            keepalive:2;
    
    
    
    };

### ngx\_http\_port\_t ###

typedef struct {
    
        /* ngx_http_in_addr_t or ngx_http_in6_addr_t */
    
        void                      *addrs;
    
        ngx_uint_t                 naddrs;
    
    } ngx_http_port_t;

### ngx\_http\_in\_addr\_t ###

typedef struct {
    
        in_addr_t                  addr;
    
        ngx_http_addr_conf_t       conf;
    
    } ngx_http_in_addr_t;

### ngx\_http\_addr\_conf\_s ###

struct ngx_http_addr_conf_s {
    
        /* the default server configuration for this address:port */
    
        ngx_http_core_srv_conf_t  *default_server;
    
    
    
        ngx_http_virtual_names_t  *virtual_names;
    
    
    
    #if (NGX_HTTP_SSL)
    
        unsigned                   ssl:1;
    
    #endif
    
    #if (NGX_HTTP_SPDY)
    
        unsigned                   spdy:1;
    
    #endif
    
        unsigned                   proxy_protocol:1;
    
    };

## 3、源码解析 ##

### ngx\_http\_core\_server\_name ###

**函数功能：**解析server\_name指令。

static char *
    
    ngx_http_core_server_name(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
    
    {
    
        ngx_http_core_srv_conf_t *cscf = conf;
    
    
    
        u_char                   ch;
    
        ngx_str_t               *value;
    
        ngx_uint_t               i;
    
        ngx_http_server_name_t  *sn;
    
    
    
        value = cf->args->elts;
    
    
    
        for (i = 1; i < cf->args->nelts; i++) {
    
    
    
            ch = value[i].data[0];
    
    
    
            if ((ch == '*' && (value[i].len < 3 || value[i].data[1] != '.'))
    
                || (ch == '.' && value[i].len < 2))
    
            {
    
                ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
    
                                   "server name \"%V\" is invalid", &value[i]);
    
                return NGX_CONF_ERROR;
    
            }
    
    
    
            if (ngx_strchr(value[i].data, '/')) {
    
                ngx_conf_log_error(NGX_LOG_WARN, cf, 0,
    
                                   "server name \"%V\" has suspicious symbols",
    
                                   &value[i]);
    
            }
    
    
    
            sn = ngx_array_push(&cscf->server_names);
    
            if (sn == NULL) {
    
                return NGX_CONF_ERROR;
    
            }
    
            sn->server = cscf;
    
    
    
            if (ngx_strcasecmp(value[i].data, (u_char *) "$hostname") == 0) {
    
                sn->name = cf->cycle->hostname;
    
            } else {
    
                sn->name = value[i];
    
            }
    
    
    
            if (value[i].data[0] != '~') {
    
                ngx_strlow(sn->name.data, sn->name.data, sn->name.len);
    
                continue;
    
            }
    
    。。。
    
        }
    
    
    
        return NGX_CONF_OK;
    
    }

### ngx\_http\_core\_listen ###

**函数功能：**解析listen指令。

static char *
    
    ngx_http_core_listen(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
    
    {
    
        ngx_http_core_srv_conf_t *cscf = conf;
    
    
    
        ngx_str_t              *value, size;
    
        ngx_url_t               u;
    
        ngx_uint_t              n;
    
        ngx_http_listen_opt_t   lsopt;
    
    
    
        cscf->listen = 1;
    
    
    
        value = cf->args->elts;
    
    
    
        ngx_memzero(&u, sizeof(ngx_url_t));
    
    
    
        u.url = value[1];
    
        u.listen = 1;
    
    u.default_port = 80;
    
    
    
        //解析listen命令后面的参数，ip:port
    
        if (ngx_parse_url(cf->pool, &u) != NGX_OK) {
    
            if (u.err) {
    
                ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
    
                                   "%s in \"%V\" of the \"listen\" directive",
    
                                   u.err, &u.url);
    
            }
    
    
    
            return NGX_CONF_ERROR;
    
        }
    
    
    
        ngx_memzero(&lsopt, sizeof(ngx_http_listen_opt_t));
    
        ngx_memcpy(&lsopt.u.sockaddr, u.sockaddr, u.socklen);
    
    
    
        lsopt.socklen = u.socklen;
    
        lsopt.backlog = NGX_LISTEN_BACKLOG;
    
        lsopt.rcvbuf = -1;
    
        lsopt.sndbuf = -1;
    
        lsopt.wildcard = u.wildcard;   //listen 80
    
    
    
        (void) ngx_sock_ntop(&lsopt.u.sockaddr, lsopt.socklen, lsopt.addr,
    
                             NGX_SOCKADDR_STRLEN, 1);
    
    
    
        for (n = 2; n < cf->args->nelts; n++) {
    
    
    
            if (ngx_strcmp(value[n].data, "default_server") == 0
    
                || ngx_strcmp(value[n].data, "default") == 0)
    
            {
    
                lsopt.default_server = 1;
    
                continue;
    
            }
    
            ….
    
            if (ngx_strncmp(value[n].data, "backlog=", 8) == 0) {
    
                lsopt.backlog = ngx_atoi(value[n].data + 8, value[n].len - 8);
    
                lsopt.set = 1;
    
                lsopt.bind = 1;
    
    
    
                if (lsopt.backlog == NGX_ERROR || lsopt.backlog == 0) {
    
                    ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
    
                                       "invalid backlog \"%V\"", &value[n]);
    
                    return NGX_CONF_ERROR;
    
                }
    
    
    
                continue;
    
            }
    
    
    
            if (ngx_strcmp(value[n].data, "ssl") == 0) {
    
    #if (NGX_HTTP_SSL)
    
                lsopt.ssl = 1;
    
                continue;
    
    #else
    
                ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
    
                                   "the \"ssl\" parameter requires "
    
                                   "ngx_http_ssl_module");
    
                return NGX_CONF_ERROR;
    
    #endif
    
            }
    
    
    
            if (ngx_strcmp(value[n].data, "spdy") == 0) {
    
    #if (NGX_HTTP_SPDY)
    
                lsopt.spdy = 1;
    
                continue;
    
    #else
    
                ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
    
                                   "the \"spdy\" parameter requires "
    
                                   "ngx_http_spdy_module");
    
                return NGX_CONF_ERROR;
    
    #endif
    
            }
    
            ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
    
                               "invalid parameter \"%V\"", &value[n]);
    
            return NGX_CONF_ERROR;
    
    }
    
    
    
        //将解析到的虚拟主机的地址信息加入到监听列表中
    
        if (ngx_http_add_listen(cf, cscf, &lsopt) == NGX_OK) {
    
            return NGX_CONF_OK;
    
        }
    
    
    
        return NGX_CONF_ERROR;
    
    }

### ngx\_http\_add\_listen ###

**函数功能：**以port为粒度，添加addr（即1.1.1.1:80、2.2.2.2:80和80，会放在相同的cmcf->port\[i\]中）。

ngx_int_t
    
    ngx_http_add_listen(ngx_conf_t *cf, ngx_http_core_srv_conf_t *cscf,
    
        ngx_http_listen_opt_t *lsopt)
    
    {
    
        in_port_t                   p;
    
        ngx_uint_t                  i;
    
        struct sockaddr            *sa;
    
        struct sockaddr_in         *sin;
    
        ngx_http_conf_port_t       *port;
    
        ngx_http_core_main_conf_t  *cmcf;
    
    
    
        cmcf = ngx_http_conf_get_module_main_conf(cf, ngx_http_core_module);
    
    
    
        if (cmcf->ports == NULL) {   //全局
    
            cmcf->ports = ngx_array_create(cf->temp_pool, 2,
    
                                           sizeof(ngx_http_conf_port_t));
    
            if (cmcf->ports == NULL) {
    
                return NGX_ERROR;
    
            }
    
        }
    
    
    
        sa = &lsopt->u.sockaddr;
    
    
    
        switch (sa->sa_family) {
    
    …
    
    
    
        default: /* AF_INET */
    
            sin = &lsopt->u.sockaddr_in;
    
            p = sin->sin_port;
    
            break;
    
        }
    
    
    
        port = cmcf->ports->elts;
    
        for (i = 0; i < cmcf->ports->nelts; i++) {
    
    
    
            if (p != port[i].port || sa->sa_family != port[i].family) {
    
                continue;
    
            }
    
    
    
            //相同的port共用相同的address
    
            return ngx_http_add_addresses(cf, cscf, &port[i], lsopt);
    
        }
    
    
    
        port = ngx_array_push(cmcf->ports);
    
        if (port == NULL) {
    
            return NGX_ERROR;
    
        }
    
    
    
        port->family = sa->sa_family;
    
        port->port = p;
    
        port->addrs.elts = NULL;
    
    
    
        return ngx_http_add_address(cf, cscf, port, lsopt);
    
    }

### ngx\_http\_add\_addresses ###

**函数功能：**相同的port，相同的addr，则ngx\_http\_add\_server（如listen 8080，server\_name hello和server\_name world），相同的port，不同的addr，则ngx\_http\_add\_address（如listen 1.1.1.1:80和2.2.2.2:80）。

static ngx_int_t
    
    ngx_http_add_addresses(ngx_conf_t *cf, ngx_http_core_srv_conf_t *cscf,
    
        ngx_http_conf_port_t *port, ngx_http_listen_opt_t *lsopt)
    
    {
    
        u_char                *p;
    
        size_t                 len, off;
    
        ngx_uint_t             i, default_server;
    
        struct sockaddr       *sa;
    
        ngx_http_conf_addr_t  *addr;
    
    #if (NGX_HTTP_SSL)
    
        ngx_uint_t             ssl;
    
    #endif
    
    #if (NGX_HTTP_SPDY)
    
        ngx_uint_t             spdy;
    
    #endif
    
    
    
        sa = &lsopt->u.sockaddr;
    
    
    
        switch (sa->sa_family) {
    
    
    
        default: /* AF_INET */
    
            off = offsetof(struct sockaddr_in, sin_addr);  // 4
    
            len = 4;
    
            break;
    
        }
    
    
    
        p = lsopt->u.sockaddr_data + off;  //u_char
    
    
    
        addr = port->addrs.elts;
    
    
    
        for (i = 0; i < port->addrs.nelts; i++) {
    
    
    
            if (ngx_memcmp(p, addr[i].opt.u.sockaddr_data + off, len) != 0) {   //比较sin_addr
    
                continue;
    
            }
    
    
    
            //相同的addr:port，不同的server_name
    
            if (ngx_http_add_server(cf, cscf, &addr[i]) != NGX_OK) {
    
                return NGX_ERROR;
    
            }
    
    
    
            /* preserve default_server bit during listen options overwriting */
    
            default_server = addr[i].opt.default_server;
    
    
    
    #if (NGX_HTTP_SSL)
    
            ssl = lsopt->ssl || addr[i].opt.ssl;
    
    #endif
    
    #if (NGX_HTTP_SPDY)
    
            spdy = lsopt->spdy || addr[i].opt.spdy;
    
    #endif
    
    
    
            if (lsopt->set) {
    
    
    
                if (addr[i].opt.set) {
    
                    ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
    
                            "duplicate listen options for %s", addr[i].opt.addr);
    
                    return NGX_ERROR;
    
                }
    
    
    
                addr[i].opt = *lsopt;
    
            }
    
    
    
            /* check the duplicate "default" server for this address:port */
    
            if (lsopt->default_server) {
    
    
    
                if (default_server) {
    
                    ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
    
                            "a duplicate default server for %s", addr[i].opt.addr);
    
                    return NGX_ERROR;
    
                }
    
    
    
                default_server = 1;
    
                addr[i].default_server = cscf;
    
            }
    
    
    
            addr[i].opt.default_server = default_server;
    
    #if (NGX_HTTP_SSL)
    
            addr[i].opt.ssl = ssl;
    
    #endif
    
    #if (NGX_HTTP_SPDY)
    
            addr[i].opt.spdy = spdy;
    
    #endif
    
    
    
            return NGX_OK;
    
        }
    
    
    
        /* add the address to the addresses list that bound to this port */
    
        return ngx_http_add_address(cf, cscf, port, lsopt);
    
    }

### ngx\_http\_add\_address ###

static ngx_int_t
    
    ngx_http_add_address(ngx_conf_t *cf, ngx_http_core_srv_conf_t *cscf,
    
        ngx_http_conf_port_t *port, ngx_http_listen_opt_t *lsopt)
    
    {
    
        ngx_http_conf_addr_t  *addr;
    
    
    
        if (port->addrs.elts == NULL) {
    
            if (ngx_array_init(&port->addrs, cf->temp_pool, 4,
    
                               sizeof(ngx_http_conf_addr_t))
    
                != NGX_OK)
    
            {
    
                return NGX_ERROR;
    
            }
    
        }
    
    
    
        addr = ngx_array_push(&port->addrs);
    
        if (addr == NULL) {
    
            return NGX_ERROR;
    
        }
    
    
    
        addr->opt = *lsopt;
    
        addr->hash.buckets = NULL;
    
        addr->hash.size = 0;
    
        addr->wc_head = NULL;
    
        addr->wc_tail = NULL;
    
    #if (NGX_PCRE)
    
        addr->nregex = 0;
    
        addr->regex = NULL;
    
    #endif
    
        addr->default_server = cscf;
    
        addr->servers.elts = NULL;
    
    
    
        return ngx_http_add_server(cf, cscf, addr);
    
    }

### ngx\_http\_add\_server ###

**函数功能：**将新的虚拟主机信息加入到这个地址的虚拟主机列表中。

static ngx_int_t
    
    ngx_http_add_server(ngx_conf_t *cf, ngx_http_core_srv_conf_t *cscf,
    
        ngx_http_conf_addr_t *addr)
    
    {
    
        ngx_uint_t                  i;
    
        ngx_http_core_srv_conf_t  **server;
    
    
    
        if (addr->servers.elts == NULL) {
    
            if (ngx_array_init(&addr->servers, cf->temp_pool, 4,
    
                               sizeof(ngx_http_core_srv_conf_t *))
    
                != NGX_OK)
    
            {
    
                return NGX_ERROR;
    
            }
    
    
    
        } else {
    
            server = addr->servers.elts;
    
            for (i = 0; i < addr->servers.nelts; i++) {  //相同的server，相同的listen
    
                if (server[i] == cscf) {
    
                    ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
    
                                       "a duplicate listen %s", addr->opt.addr);
    
                    return NGX_ERROR;
    
                }
    
            }
    
        }
    
    
    
        server = ngx_array_push(&addr->servers);
    
        if (server == NULL) {
    
            return NGX_ERROR;
    
        }
    
    
    
        *server = cscf;
    
    
    
        return NGX_OK;
    
    }

### ngx\_http\_block->ngx\_http\_optimize\_servers ###

**函数功能：**ngx\_http\_block的最后一步。

static ngx_int_t
    
    ngx_http_optimize_servers(ngx_conf_t *cf, ngx_http_core_main_conf_t *cmcf,
    
        ngx_array_t *ports)
    
    {
    
        ngx_uint_t             p, a;
    
        ngx_http_conf_port_t  *port;
    
        ngx_http_conf_addr_t  *addr;
    
    
    
        if (ports == NULL) {
    
            return NGX_OK;
    
        }
    
    
    
        port = ports->elts;
    
        for (p = 0; p < ports->nelts; p++) {
    
            //比如listen 80和listen 127.0.0.1:80
    
            //排序原则：通配符如listen 80和listen*:80，会排在最后面，listen 1.1.1.1:80 backlog=512等会排在最前面
    
            ngx_sort(port[p].addrs.elts, (size_t) port[p].addrs.nelts,
    
                     sizeof(ngx_http_conf_addr_t), ngx_http_cmp_conf_addrs);
    
    
    
            addr = port[p].addrs.elts;
    
            for (a = 0; a < port[p].addrs.nelts; a++) {
    
    
    
                if (addr[a].servers.nelts > 1   //相同的addr:port，不同的server_name
    
    #if (NGX_PCRE)
    
                    || addr[a].default_server->captures
    
    #endif
    
                   )
    
                {
    
                    if (ngx_http_server_names(cf, cmcf, &addr[a]) != NGX_OK) {
    
                        return NGX_ERROR;
    
                    }
    
                }
    
            }
    
    
    
            if (ngx_http_init_listening(cf, &port[p]) != NGX_OK) {  //一个port，一个listening
    
                return NGX_ERROR;
    
            }
    
        }
    
    
    
        return NGX_OK;
    
    }

### ngx\_http\_server\_names ###

**函数功能：**相同的addr:port的优化处理。

static ngx_int_t
    
    ngx_http_server_names(ngx_conf_t *cf, ngx_http_core_main_conf_t *cmcf,
    
        ngx_http_conf_addr_t *addr)
    
    {
    
        ngx_int_t                   rc;
    
        ngx_uint_t                  n, s;
    
        ngx_hash_init_t             hash;
    
        ngx_hash_keys_arrays_t      ha;
    
        ngx_http_server_name_t     *name;
    
        ngx_http_core_srv_conf_t  **cscfp;
    
    
    
        ngx_memzero(&ha, sizeof(ngx_hash_keys_arrays_t));
    
    
    
        ha.temp_pool = ngx_create_pool(NGX_DEFAULT_POOL_SIZE, cf->log);
    
        if (ha.temp_pool == NULL) {
    
            return NGX_ERROR;
    
        }
    
    
    
        ha.pool = cf->pool;
    
    
    
        if (ngx_hash_keys_array_init(&ha, NGX_HASH_LARGE) != NGX_OK) {
    
            goto failed;
    
        }
    
    
    
        cscfp = addr->servers.elts;
    
    
    
        for (s = 0; s < addr->servers.nelts; s++) {
    
    
    
            name = cscfp[s]->server_names.elts;   //一个server可以有多个server_name
    
    
    
            for (n = 0; n < cscfp[s]->server_names.nelts; n++) {
    
    
    
                rc = ngx_hash_add_key(&ha, &name[n].name, name[n].server,
    
                                      NGX_HASH_WILDCARD_KEY);
    
    
    
                if (rc == NGX_ERROR) {
    
                    return NGX_ERROR;
    
                }
    
    
    
                if (rc == NGX_DECLINED) {
    
                    ngx_log_error(NGX_LOG_EMERG, cf->log, 0,
    
                                  "invalid server name or wildcard \"%V\" on %s",
    
                                  &name[n].name, addr->opt.addr);
    
                    return NGX_ERROR;
    
                }
    
    
    
                if (rc == NGX_BUSY) {
    
                    ngx_log_error(NGX_LOG_WARN, cf->log, 0,
    
                                  "conflicting server name \"%V\" on %s, ignored",
    
                                  &name[n].name, addr->opt.addr);
    
                }
    
            }
    
        }
    
    
    
        hash.key = ngx_hash_key_lc;
    
        hash.max_size = cmcf->server_names_hash_max_size;
    
        hash.bucket_size = cmcf->server_names_hash_bucket_size;
    
        hash.name = "server_names_hash";
    
        hash.pool = cf->pool;
    
    
    
        if (ha.keys.nelts) {   //无通配
    
            hash.hash = &addr->hash;
    
            hash.temp_pool = NULL;
    
    
    
            if (ngx_hash_init(&hash, ha.keys.elts, ha.keys.nelts) != NGX_OK) {
    
                goto failed;
    
            }
    
        }
    
    
    
        if (ha.dns_wc_head.nelts) {  //前缀通配
    
    
    
            ngx_qsort(ha.dns_wc_head.elts, (size_t) ha.dns_wc_head.nelts,
    
                      sizeof(ngx_hash_key_t), ngx_http_cmp_dns_wildcards);
    
    
    
            hash.hash = NULL;
    
            hash.temp_pool = ha.temp_pool;
    
    
    
            if (ngx_hash_wildcard_init(&hash, ha.dns_wc_head.elts,
    
                                       ha.dns_wc_head.nelts)
    
                != NGX_OK)
    
            {
    
                goto failed;
    
            }
    
    
    
            addr->wc_head = (ngx_hash_wildcard_t *) hash.hash;
    
        }
    
    
    
        if (ha.dns_wc_tail.nelts) {  //后缀通配
    
    
    
            ngx_qsort(ha.dns_wc_tail.elts, (size_t) ha.dns_wc_tail.nelts,
    
                      sizeof(ngx_hash_key_t), ngx_http_cmp_dns_wildcards);
    
    
    
            hash.hash = NULL;
    
            hash.temp_pool = ha.temp_pool;
    
    
    
            if (ngx_hash_wildcard_init(&hash, ha.dns_wc_tail.elts,
    
                                       ha.dns_wc_tail.nelts)
    
                != NGX_OK)
    
            {
    
                goto failed;
    
            }
    
    
    
            addr->wc_tail = (ngx_hash_wildcard_t *) hash.hash;
    
        }
    
    
    
        ngx_destroy_pool(ha.temp_pool);
    
    
    
        return NGX_OK;
    
    
    
    failed:
    
    
    
        ngx_destroy_pool(ha.temp_pool);
    
    
    
        return NGX_ERROR;
    
    }

### ngx\_http\_cmp\_conf\_addrs ###

static ngx_int_t
    
    ngx_http_cmp_conf_addrs(const void *one, const void *two)
    
    {
    
        ngx_http_conf_addr_t  *first, *second;
    
    
    
        first = (ngx_http_conf_addr_t *) one;
    
        second = (ngx_http_conf_addr_t *) two;
    
    
    
        //通配符必须是最后一个，返回1，则表示要交换顺序
    
        if (first->opt.wildcard) {
    
            /* a wildcard address must be the last resort, shift it to the end */
    
            return 1;
    
        }
    
    
    
         //通配符必须是最后一个，不需要换位置
    
        if (second->opt.wildcard) {
    
            /* a wildcard address must be the last resort, shift it to the end */
    
            return -1;
    
        }
    
       
    
       //设置如backlog的，需要放在前面
    
        if (first->opt.bind && !second->opt.bind) {
    
            /* shift explicit bind()ed addresses to the start */
    
            return -1;
    
    }
    
    
    
        //设置如backlog的，需要放在前面
    
        if (!first->opt.bind && second->opt.bind) {
    
            /* shift explicit bind()ed addresses to the start */
    
            return 1;
    
        }
    
    
    
        /* do not sort by default */
    
        return 0;
    
    }

### ngx\_http\_init\_listening（重要） ###

**函数功能：**用新的结构（cycle-> listening）存储这些关系。

static ngx_int_t
    
    ngx_http_init_listening(ngx_conf_t *cf, ngx_http_conf_port_t *port)
    
    {
    
        ngx_uint_t                 i, last, bind_wildcard;
    
        ngx_listening_t           *ls;
    
        ngx_http_port_t           *hport;
    
        ngx_http_conf_addr_t      *addr;
    
    
    
        addr = port->addrs.elts;
    
        last = port->addrs.nelts;      //相同的port，不同的addr个数
    
    
    
        if (addr[last - 1].opt.wildcard) { //通配符需要放在最后一个，设置backlog的需要放在前面
    
            addr[last - 1].opt.bind = 1;
    
            bind_wildcard = 1;
    
        } else {
    
            bind_wildcard = 0;
    
        }
    
    
    
        i = 0;
    
    
    
        while (i < last) {
    
            if (bind_wildcard && !addr[i].opt.bind) {
    
                i++;
    
                continue;
    
            }
    
    
    
            //这个函数里面将会创建，并且初始化listen结构，这个listen已经存放在cycle结构的listen数组中
    
            ls = ngx_http_add_listening(cf, &addr[i]);    //port->addrs.elts
    
            if (ls == NULL) {
    
                return NGX_ERROR;
    
            }
    
    
    
            hport = ngx_pcalloc(cf->pool, sizeof(ngx_http_port_t));
    
            if (hport == NULL) {
    
                return NGX_ERROR;
    
            }
    
    
    
            ls->servers = hport;
    
    
    
            if (i == last - 1) {
    
                hport->naddrs = last;  //将*:port和没有显式bind的address:port放在同一个listen中，如listen 80和listen 1.1.1.1:80可以放在一个listening中
    
            } else {
    
                hport->naddrs = 1;
    
    //重新赋值为0，因为最前面可能是listen 2.2.2.2:80 backlog=512这样的
    
                i = 0;                  
    
    }
    
    
    
            switch (ls->sockaddr->sa_family) {
    
    
    
            default: /* AF_INET */
    
                if (ngx_http_add_addrs(cf, hport, addr) != NGX_OK) {
    
                    return NGX_ERROR;
    
                }
    
                break;
    
            }
    
    
    
            addr++;
    
            last--;
    
        }
    
    
    
        return NGX_OK;
    
    }

ngx\_http\_add\_listening

static ngx_listening_t *
    
    ngx_http_add_listening(ngx_conf_t *cf, ngx_http_conf_addr_t *addr)
    
    {
    
        ngx_listening_t           *ls;
    
        ngx_http_core_loc_conf_t  *clcf;
    
        ngx_http_core_srv_conf_t  *cscf;
    
    
    
        ls = ngx_create_listening(cf, &addr->opt.u.sockaddr, addr->opt.socklen);
    
        if (ls == NULL) {
    
            return NULL;
    
        }
    
    
    
        ls->addr_ntop = 1;
    
    
    
        ls->handler = ngx_http_init_connection;
    
    
    
        cscf = addr->default_server;
    
        ls->pool_size = cscf->connection_pool_size;
    
        ls->post_accept_timeout = cscf->client_header_timeout;
    
    
    
        clcf = cscf->ctx->loc_conf[ngx_http_core_module.ctx_index];
    
    
    
        ls->logp = clcf->error_log;
    
        ls->log.data = &ls->addr_text;
    
        ls->log.handler = ngx_accept_log_error;
    
    
    
        ls->backlog = addr->opt.backlog;
    
        ls->rcvbuf = addr->opt.rcvbuf;
    
        ls->sndbuf = addr->opt.sndbuf;
    
    
    
    ls->keepalive = addr->opt.so_keepalive;
    
    
    
        return ls;
    
    }

ngx\_create\_listening

ngx_listening_t *
    
    ngx_create_listening(ngx_conf_t *cf, void *sockaddr, socklen_t socklen)
    
    {
    
        size_t            len;
    
        ngx_listening_t  *ls;
    
        struct sockaddr  *sa;
    
        u_char            text[NGX_SOCKADDR_STRLEN];
    
    
    
        ls = ngx_array_push(&cf->cycle->listening);
    
        if (ls == NULL) {
    
            return NULL;
    
        }
    
    
    
        ngx_memzero(ls, sizeof(ngx_listening_t));
    
    
    
        sa = ngx_palloc(cf->pool, socklen);
    
        if (sa == NULL) {
    
            return NULL;
    
        }
    
    
    
        ngx_memcpy(sa, sockaddr, socklen);
    
    
    
        ls->sockaddr = sa;
    
        ls->socklen = socklen;
    
    
    
        len = ngx_sock_ntop(sa, socklen, text, NGX_SOCKADDR_STRLEN, 1);
    
        ls->addr_text.len = len;
    
    
    
        switch (ls->sockaddr->sa_family) {
    
        case AF_INET:
    
             ls->addr_text_max_len = NGX_INET_ADDRSTRLEN;
    
             break;
    
        default:
    
             ls->addr_text_max_len = NGX_SOCKADDR_STRLEN;
    
             break;
    
        }
    
    
    
        ls->addr_text.data = ngx_pnalloc(cf->pool, len);
    
        if (ls->addr_text.data == NULL) {
    
            return NULL;
    
        }
    
    
    
        ngx_memcpy(ls->addr_text.data, text, len);
    
    
    
        ls->fd = (ngx_socket_t) -1;
    
        ls->type = SOCK_STREAM;
    
    
    
        ls->backlog = NGX_LISTEN_BACKLOG;  //511
    
        ls->rcvbuf = -1;
    
    ls->sndbuf = -1;
    
    
    
        return ls;
    
    }

ngx\_http\_add\_addrs

static ngx_int_t
    
    ngx_http_add_addrs(ngx_conf_t *cf, ngx_http_port_t *hport,
    
        ngx_http_conf_addr_t *addr)
    
    {
    
        ngx_uint_t                 i;
    
        ngx_http_in_addr_t        *addrs;
    
        struct sockaddr_in        *sin;
    
        ngx_http_virtual_names_t  *vn;
    
    
    
        hport->addrs = ngx_pcalloc(cf->pool,
    
                                   hport->naddrs * sizeof(ngx_http_in_addr_t));
    
        if (hport->addrs == NULL) {
    
            return NGX_ERROR;
    
        }
    
    
    
        addrs = hport->addrs;
    
    
    
        for (i = 0; i < hport->naddrs; i++) {
    
    
    
            sin = &addr[i].opt.u.sockaddr_in;
    
            addrs[i].addr = sin->sin_addr.s_addr;
    
    
    
            addrs[i].conf.default_server = addr[i].default_server;
    
    #if (NGX_HTTP_SSL)
    
            addrs[i].conf.ssl = addr[i].opt.ssl;
    
    #endif
    
    #if (NGX_HTTP_SPDY)
    
            addrs[i].conf.spdy = addr[i].opt.spdy;
    
    #endif
    
            addrs[i].conf.proxy_protocol = addr[i].opt.proxy_protocol;
    
    
    
            if (addr[i].hash.buckets == NULL
    
                && (addr[i].wc_head == NULL
    
                    || addr[i].wc_head->hash.buckets == NULL)
    
                && (addr[i].wc_tail == NULL
    
                    || addr[i].wc_tail->hash.buckets == NULL)
    
    #if (NGX_PCRE)
    
                && addr[i].nregex == 0
    
    #endif
    
                )
    
            {
    
                continue;
    
            }
    
    
    
            vn = ngx_palloc(cf->pool, sizeof(ngx_http_virtual_names_t));
    
            if (vn == NULL) {
    
                return NGX_ERROR;
    
            }
    
    
    
            addrs[i].conf.virtual_names = vn;
    
    
    
            vn->names.hash = addr[i].hash;
    
            vn->names.wc_head = addr[i].wc_head;
    
            vn->names.wc_tail = addr[i].wc_tail;
    
    #if (NGX_PCRE)
    
            vn->nregex = addr[i].nregex;
    
            vn->regex = addr[i].regex;
    
    #endif
    
        }
    
    
    
        return NGX_OK;
    
    }

### ngx\_init\_cycle ###

if (old_cycle->listening.nelts) {
    
            ls = old_cycle->listening.elts;
    
            for (i = 0; i < old_cycle->listening.nelts; i++) {
    
                ls[i].remain = 0;
    
            }
    
    
    
            nls = cycle->listening.elts;
    
            for (n = 0; n < cycle->listening.nelts; n++) {
    
    
    
                for (i = 0; i < old_cycle->listening.nelts; i++) {
    
                    if (ls[i].ignore) {
    
                        continue;
    
                    }
    
    
    
                    //地址相同
    
                    if (ngx_cmp_sockaddr(nls[n].sockaddr, nls[n].socklen,
    
                                         ls[i].sockaddr, ls[i].socklen, 1)
    
                        == NGX_OK)
    
                    {
    
                        nls[n].fd = ls[i].fd;
    
                        nls[n].previous = &ls[i];
    
                        ls[i].remain = 1;        //当remain=1时，old_cycle不需要close fd()
    
    
    
                        if (ls[i].backlog != nls[n].backlog) {
    
                            nls[n].listen = 1;   //backlog不同的时候，会在configure_listening_sockets中重新listen(fd, backlog)
    
                        }
    
                        break;
    
                    }
    
                }
    
    
    
                if (nls[n].fd == (ngx_socket_t) -1) {
    
                    nls[n].open = 1;
    
                }
    
            }
    
    
    
        } else {
    
            ls = cycle->listening.elts;
    
            for (i = 0; i < cycle->listening.nelts; i++) {
    
                ls[i].open = 1;
    
            }
    
        }
    
    
    
        if (ngx_open_listening_sockets(cycle) != NGX_OK) {
    
            goto failed;
    
    }
    
    
    
    ….
    
    ls = old_cycle->listening.elts;
    
    for (i = 0; i < old_cycle->listening.nelts; i++) {
    
    
    
        if (ls[i].remain || ls[i].fd == (ngx_socket_t) -1) {
    
          continue;
    
        }
    
    
    
        if (ngx_close_socket(ls[i].fd) == -1) {
    
            ngx_log_error(NGX_LOG_EMERG, log, ngx_socket_errno,
    
                              ngx_close_socket_n " listening socket on %V failed",
    
                              &ls[i].addr_text);
    
        }
    
    }

### ngx\_open\_listening\_sockets ###

ngx_int_t
    
    ngx_open_listening_sockets(ngx_cycle_t *cycle)
    
    {
    
        int               reuseaddr;
    
        ngx_uint_t        i, tries, failed;
    
        ngx_err_t         err;
    
        ngx_log_t        *log;
    
        ngx_socket_t      s;
    
        ngx_listening_t  *ls;
    
    
    
        reuseaddr = 1;
    
    #if (NGX_SUPPRESS_WARN)
    
        failed = 0;
    
    #endif
    
    
    
        log = cycle->log;
    
    
    
        /* TODO: configurable try number */
    
    
    
        for (tries = 5; tries; tries--) {
    
            failed = 0;
    
    
    
            /* for each listening socket */
    
    
    
            ls = cycle->listening.elts;
    
            for (i = 0; i < cycle->listening.nelts; i++) {
    
    
    
                if (ls[i].ignore) {     //和inherited_sockets有关
    
                    continue;
    
                }
    
    
    
                if (ls[i].fd != (ngx_socket_t) -1) {
    
                    continue;
    
                }
    
    
    
                if (ls[i].inherited) {
    
                    continue;
    
                }
    
    
    
                s = ngx_socket(ls[i].sockaddr->sa_family, ls[i].type, 0);
    
    
    
                if (s == (ngx_socket_t) -1) {
    
                    ngx_log_error(NGX_LOG_EMERG, log, ngx_socket_errno,
    
                                  ngx_socket_n " %V failed", &ls[i].addr_text);
    
                    return NGX_ERROR;
    
                }
    
    
    
                if (setsockopt(s, SOL_SOCKET, SO_REUSEADDR,
    
                               (const void *) &reuseaddr, sizeof(int))
    
                    == -1)
    
                {
    
                    ngx_log_error(NGX_LOG_EMERG, log, ngx_socket_errno,
    
                                  "setsockopt(SO_REUSEADDR) %V failed",
    
                                  &ls[i].addr_text);
    
    
    
                    if (ngx_close_socket(s) == -1) {
    
                        ngx_log_error(NGX_LOG_EMERG, log, ngx_socket_errno,
    
                                      ngx_close_socket_n " %V failed",
    
                                      &ls[i].addr_text);
    
                    }
    
    
    
                    return NGX_ERROR;
    
                }
    
    
    
                if (!(ngx_event_flags & NGX_USE_AIO_EVENT)) {
    
                    if (ngx_nonblocking(s) == -1) {
    
                        ngx_log_error(NGX_LOG_EMERG, log, ngx_socket_errno,
    
                                      ngx_nonblocking_n " %V failed",
    
                                      &ls[i].addr_text);
    
    
    
                        if (ngx_close_socket(s) == -1) {
    
                            ngx_log_error(NGX_LOG_EMERG, log, ngx_socket_errno,
    
                                          ngx_close_socket_n " %V failed",
    
                                          &ls[i].addr_text);
    
                        }
    
    
    
                        return NGX_ERROR;
    
                    }
    
                }
    
    
    
    
    
                if (bind(s, ls[i].sockaddr, ls[i].socklen) == -1) {
    
                    err = ngx_socket_errno;
    
    
    
                    if (err == NGX_EADDRINUSE && ngx_test_config) {
    
                        continue;
    
                    }
    
    
    
                    ngx_log_error(NGX_LOG_EMERG, log, err,
    
                                  "bind() to %V failed", &ls[i].addr_text);
    
    
    
                    if (ngx_close_socket(s) == -1) {
    
                        ngx_log_error(NGX_LOG_EMERG, log, ngx_socket_errno,
    
                                      ngx_close_socket_n " %V failed",
    
                                      &ls[i].addr_text);
    
                    }
    
    
    
                    if (err != NGX_EADDRINUSE) {
    
                        return NGX_ERROR;
    
                    }
    
    
    
                    failed = 1;
    
    
    
                    continue;
    
                }
    
    
    
                //如listen 80和listen 1.1.1.1:80 共用一个listening，即共用一个backlog
    
                if (listen(s, ls[i].backlog) == -1) {
    
                    ngx_log_error(NGX_LOG_EMERG, log, ngx_socket_errno,
    
                                  "listen() to %V, backlog %d failed",
    
                                  &ls[i].addr_text, ls[i].backlog);
    
    
    
                    if (ngx_close_socket(s) == -1) {
    
                        ngx_log_error(NGX_LOG_EMERG, log, ngx_socket_errno,
    
                                      ngx_close_socket_n " %V failed",
    
                                      &ls[i].addr_text);
    
                    }
    
    
    
                    return NGX_ERROR;
    
                }
    
    
    
                ls[i].listen = 1;
    
    
    
                ls[i].fd = s;
    
            }
    
    
    
            if (!failed) {
    
                break;
    
            }
    
    
    
            /* TODO: delay configurable */
    
    
    
            ngx_log_error(NGX_LOG_NOTICE, log, 0,
    
                          "try again to bind() after 500ms");
    
    
    
            ngx_msleep(500);
    
        }
    
    
    
        if (failed) {
    
            ngx_log_error(NGX_LOG_EMERG, log, 0, "still could not bind()");
    
            return NGX_ERROR;
    
        }
    
    
    
        return NGX_OK;
    
    }

### ngx\_configure\_listening\_sockets ###

void
    
    ngx_configure_listening_sockets(ngx_cycle_t *cycle)
    
    {
    
        int                        value;
    
        ngx_uint_t                 i;
    
        ngx_listening_t           *ls;
    
    
    
        ls = cycle->listening.elts;
    
        for (i = 0; i < cycle->listening.nelts; i++) {
    
    
    
            ls[i].log = *ls[i].logp;
    
    
    
            。。。
    
            if (ls[i].keepalive) {
    
                value = (ls[i].keepalive == 1) ? 1 : 0;
    
    
    
                if (setsockopt(ls[i].fd, SOL_SOCKET, SO_KEEPALIVE,
    
                               (const void *) &value, sizeof(int))
    
                    == -1)
    
                {
    
                    ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_socket_errno,
    
                                  "setsockopt(SO_KEEPALIVE, %d) %V failed, ignored",
    
                                  value, &ls[i].addr_text);
    
                }
    
            }
    
    
    
            if (ls[i].listen) {
    
    
    
                /* change backlog via listen() */
    
                if (listen(ls[i].fd, ls[i].backlog) == -1) {
    
                    ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_socket_errno,
    
                                  "listen() to %V, backlog %d failed, ignored",
    
                                  &ls[i].addr_text, ls[i].backlog);
    
                }
    
            }
    
        }
    
    
    
        return;
    
    }

### ngx\_http\_init\_connection ###

函数功能：ngx\_event\_accept后的ls->handler= ngx\_http\_init\_connection。

void
    
    ngx_http_init_connection(ngx_connection_t *c)
    
    {
    
        ngx_uint_t              i;
    
        ngx_event_t            *rev;
    
        struct sockaddr_in     *sin;
    
        ngx_http_port_t        *port;
    
        ngx_http_in_addr_t     *addr;
    
        ngx_http_log_ctx_t     *ctx;
    
        ngx_http_connection_t  *hc;
    
    
    
        hc = ngx_pcalloc(c->pool, sizeof(ngx_http_connection_t));
    
        if (hc == NULL) {
    
            ngx_http_close_connection(c);
    
            return;
    
        }
    
    
    
        c->data = hc;
    
    
    
        /* find the server configuration for the address:port */
    
    
    
        port = c->listening->servers;   /*ngx_http_port_t */
    
        if (port->naddrs > 1) {
    
    
    
            if (ngx_connection_local_sockaddr(c, NULL, 0) != NGX_OK) {
    
                ngx_http_close_connection(c);
    
                return;
    
            }
    
    
    
            switch (c->local_sockaddr->sa_family) {
    
            default: /* AF_INET */
    
                sin = (struct sockaddr_in *) c->local_sockaddr;  //here
    
    
    
                addr = port->addrs;
    
    
    
                for (i = 0; i < port->naddrs - 1; i++) {
    
                    if (addr[i].addr == sin->sin_addr.s_addr) {
    
                        break;
    
                    }
    
                }
    
    
    
                hc->addr_conf = &addr[i].conf;
    
    
    
                break;
    
            }
    
    
    
        } else {
    
    
    
            switch (c->local_sockaddr->sa_family) {
    
            default: /* AF_INET */
    
                addr = port->addrs;
    
                hc->addr_conf = &addr[0].conf;
    
                break;
    
            }
    
        }
    
    
    
        …
    
    
    
        rev = c->read;
    
        rev->handler = ngx_http_wait_request_handler;   //普通request_handler
    
        c->write->handler = ngx_http_empty_handler;
    
    
    
    #if (NGX_HTTP_SPDY)
    
        if (hc->addr_conf->spdy) {
    
            rev->handler = ngx_http_spdy_init;         //spdy request_handler
    
        }
    
    #endif
    
    
    
    …
    
    
    
        if (rev->ready) {
    
            /* the deferred accept(), rtsig, aio, iocp */
    
    
    
            if (ngx_use_accept_mutex) {
    
                ngx_post_event(rev, &ngx_posted_events);
    
                return;
    
            }
    
    
    
            rev->handler(rev);
    
            return;
    
        }
    
    
    
        ngx_add_timer(rev, c->listening->post_accept_timeout);
    
        ngx_reusable_connection(c, 1);
    
    
    
        if (ngx_handle_read_event(rev, 0) != NGX_OK) {
    
            ngx_http_close_connection(c);
    
            return;
    
        }
    
    }