nginx模块开发—HTTP初始化之listen

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_serverunsigned                   bind:1;                    // bind/backlog/…unsigned                   wildcard:1;#if (NGX_HTTP_SSL)unsigned                   ssl:1;#endif#if (NGX_HTTP_SPDY)unsigned                   spdy:1;                  // spdy#endifunsigned                   so_keepalive:2;unsigned                   proxy_protocol:1;   // proxy_protocolint                        backlog;   // backlogint                        rcvbuf;    // rcvbufint                        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;#endifunsigned                   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:portif (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;#elsengx_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;#elsengx_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_tngx_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addressreturn 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_tngx_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;#endifsa = &lsopt->u.sockaddr;switch (sa->sa_family) {default: /* AF_INET */off = offsetof(struct sockaddr_in, sin_addr);  // 4len = 4;break;}p = lsopt->u.sockaddr_data + off;  //u_charaddr = 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_addrcontinue;}//相同的addr:port，不同的server_nameif (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;#endifif (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;#endifreturn 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_tngx_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;#endifaddr->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_tngx_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listenif (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_tngx_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listeningreturn 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_tngx_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_namefor (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_tngx_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_tngx_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.eltsif (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;  //511ls->rcvbuf = -1;ls->sndbuf = -1;return ls;}

ngx_http_add_addrs

static ngx_int_tngx_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;#endifaddrs[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_tngx_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;#endiflog = 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backlogif (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

voidngx_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。

voidngx_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;  //hereaddr = 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_handlerc->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;}}