在nginx源碼分析（4）中，看到了nginx的事件模型，但其中沒(méi)有介紹監(jiān)聽(tīng)socket的初始化。而對(duì)于web server來(lái)說(shuō)，需要通過(guò)監(jiān)聽(tīng)socket來(lái)監(jiān)聽(tīng)客戶端的連接等。本篇將會(huì)具體介紹這方面的內(nèi)容。還記得在前文介紹ngx_cycle_t結(jié)構(gòu)時(shí)，它具有一個(gè)listening屬性，是一個(gè)數(shù)組，存儲(chǔ)所有監(jiān)聽(tīng)socket，下面就來(lái)看看這些信息是什么時(shí)候添加的、以及如何初始化的。

1. 重要的數(shù)據(jù)結(jié)構(gòu)
????????1. ngx_http_conf_port_t

????????監(jiān)聽(tīng)端口配置信息，addrs是在該端口上所有監(jiān)聽(tīng)地址的數(shù)組。

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;

????????2. ngx_http_conf_addr_t

????????監(jiān)聽(tīng)地址配置信息，包含了所有在該addr:port監(jiān)聽(tīng)的所有server塊的ngx_http_core_srv_conf_t結(jié)構(gòu)，以及hash、wc_head和wc_tail這些hash結(jié)構(gòu)，保存了以server name為key，ngx_http_core_srv_conf_t為value的哈希表，用于快速查找對(duì)應(yīng)虛擬主機(jī)的配置信息。

typedef struct {ngx_http_listen_opt_t ? ? ?opt;ngx_hash_t ? ? ? ? ? ? ? ? hash;ngx_hash_wildcard_t ? ? ? *wc_head;ngx_hash_wildcard_t ? ? ? *wc_tail;#if (NGX_PCRE)ngx_uint_t ? ? ? ? ? ? ? ? nregex;ngx_http_server_name_t ? ?*regex; #endif/* the default server configuration for this address:port */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;

2. 監(jiān)聽(tīng)socket初始化
????????nginx把需要監(jiān)聽(tīng)的socket用ngx_listening_t表示，存放在ngx_cycle_t的listening數(shù)組中。具體監(jiān)聽(tīng)socket的初始化可以分為3個(gè)步驟：1. 解析配置文件、獲取監(jiān)聽(tīng)socket相關(guān)信息；2. 初始化監(jiān)聽(tīng)socket；3. 打開(kāi)并配置監(jiān)聽(tīng)socket。下面我們分步驟來(lái)查看具體細(xì)節(jié)。

（1）解析配置文件，獲取監(jiān)聽(tīng)socket信息
????????用于設(shè)置監(jiān)聽(tīng)socket的指令主要有兩個(gè)：server_name和listen。server_name指令用于實(shí)現(xiàn)虛擬主機(jī)的功能，會(huì)設(shè)置每個(gè)server塊的虛擬主機(jī)名，在處理請(qǐng)求時(shí)會(huì)根據(jù)請(qǐng)求行中的host來(lái)轉(zhuǎn)發(fā)請(qǐng)求。而listen就是設(shè)置監(jiān)聽(tīng)socket的信息。這兩個(gè)指令都是ngx_http_core_module的，首先看一下server_name指令的回調(diào)函數(shù)ngx_http_core_server_name，這個(gè)函數(shù)完成的功能很簡(jiǎn)單就是將server_name指令指定的虛擬主機(jī)名添加到ngx_http_core_srv_conf_t的server_names數(shù)組中，以便在后面對(duì)整個(gè)web server支持的虛擬主機(jī)進(jìn)行初始化。

????????1. ngx_http_core_server_name

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;// 局部變量聲明……value = cf->args->elts;for (i = 1; i < cf->args->nelts; i++) {ch = value[i].data[0];// 一些異常的處理……sn = ngx_array_push(&cscf->server_names); // 向server_names數(shù)組添加元素if (sn == NULL) {return NGX_CONF_ERROR;} #if (NGX_PCRE)sn->regex = NULL; #endifsn->server = cscf;if (ngx_strcasecmp(value[i].data, (u_char *) "$hostname") == 0) {sn->name = cf->cycle->hostname;} else {sn->name = value[i];}/* 前綴不是~就不是正則表達(dá)式，需要將server name轉(zhuǎn)換為小寫 */if (value[i].data[0] != '~') {ngx_strlow(sn->name.data, sn->name.data, sn->name.len);continue;} #if (NGX_PCRE)// 處理server name是正則表達(dá)式的情況…… ? ? ? #elsereturn NGX_CONF_ERROR; #endif}return NGX_CONF_OK; }

????????2. ngx_http_core_listen

????????下面看一下listen指令的回調(diào)函數(shù)ngx_http_core_listen。這個(gè)函數(shù)主要還解析listen指令中的socket配置選項(xiàng)，并保存這些值，在函數(shù)的最后會(huì)調(diào)用ngx_http_add_listen函數(shù)添加監(jiān)聽(tīng)socket的信息。

? ?

cscf->listen = 1;將core module的server config的listen置為1，表示該server塊已經(jīng)調(diào)用listen指令， 設(shè)置了監(jiān)聽(tīng)socket信息。如果listen等于0，即server塊沒(méi)有調(diào)用listen指令， 后面會(huì)對(duì)監(jiān)聽(tīng)信息進(jìn)行默認(rèn)初始化，比如監(jiān)聽(tīng)的端口是80，地址是localhost等。// listen指令的參數(shù)value = cf->args->elts;ngx_memzero(&u, sizeof(ngx_url_t));u.url = value[1];u.listen = 1;u.default_port = 80;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;}

????????這段代碼意圖很簡(jiǎn)單，就是解析listen指令中的url，ip地址和端口號(hào)信息。
? ?

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; #if (NGX_HAVE_SETFIB)lsopt.setfib = -1; #endiflsopt.wildcard = u.wildcard;/* 將二進(jìn)制的地址結(jié)構(gòu)，轉(zhuǎn)換為文本格式 */(void) ngx_sock_ntop(&lsopt.u.sockaddr, lsopt.addr,NGX_SOCKADDR_STRLEN, 1);

????????ngx_http_listen_opt_t用于存儲(chǔ)listen socket的配置信息，比如rcvbuf、sndbuf、backlog等，就是一些基本的socket選項(xiàng)。后面的大部分代碼主要是處理listen指令指定的配置選項(xiàng)進(jìn)行初始化，比如：default_server、rcvbuf、sndbuf、backlog等，代碼太冗長(zhǎng)，這里不粘貼。

? ? if (ngx_http_add_listen(cf, cscf, &lsopt) == NGX_OK) {return NGX_CONF_OK;}

????????在函數(shù)的最后部分調(diào)用了ngx_http_add_listen添加監(jiān)聽(tīng)socket信息。在具體介紹這個(gè)函數(shù)實(shí)現(xiàn)之前，先來(lái)看一下nginx是如何存儲(chǔ)監(jiān)聽(tīng)socket的地址信息的。
在ngx_http_core_main_conf_t中有ports屬性，保存nginx監(jiān)聽(tīng)的所有端口的信息。ports是ngx_http_conf_port_t類型的數(shù)組，而每個(gè)ngx_http_conf_port_t結(jié)構(gòu)又具有addrs屬性，它存放了對(duì)應(yīng)端口上要監(jiān)聽(tīng)的地址。addrs是ngx_http_conf_addr_t類型的數(shù)組，ngx_http_conf_addr_t結(jié)構(gòu)包含在addr:port上監(jiān)聽(tīng)的虛擬主機(jī)名及對(duì)應(yīng)的配置信息。

ngx_http_core_main_conf_t

????|---> prots： 監(jiān)聽(tīng)的端口號(hào)的數(shù)組

????????????????|---> ngx_http_conf_port_t：端口號(hào)的配置信息

???????????????????????????????|---> addrs：在該端口號(hào)上，監(jiān)聽(tīng)的所有地址的數(shù)組

????????????????????????????????????????????|---> ngx_http_conf_addr_t：地址配置信息，包含在該addr:port上的多個(gè)虛擬主機(jī)

???????????????????????????????????????????????????????????|---> servers：在addr:port上的說(shuō)個(gè)server塊的配置信息ngx_http_core_srv_conf_t

???????????????????????????????????????????????????????????| ???????????|---> ngx_http_core_srv_conf_t

???????????????????????????????????????????????????????????|---> opt：ngx_http_listen_opt_t類型，監(jiān)聽(tīng)socket的配置信息

???????????????????????????????????????????????????????????|---> hash：以server_name為key，ngx_http_core_srv_conf_t為value的hash表，并且server_name不含通配符。

???????????????????????????????????????????????????????????|---> wc_head：同hash，server_name含前綴通配符。

???????????????????????????????????????????????????????????|---> wc_tail：同hash，server_name含后綴通配符。

?????????nginx就通過(guò)這種方式將監(jiān)聽(tīng)的地址信息和端口信息組織起來(lái)，這些配置信息在后面回用于初始化ngx_cycle_t的listening屬性等。下面看一下具體實(shí)現(xiàn)。

????????3. ngx_http_add_listen? ?

cmcf = ngx_http_conf_get_module_main_conf(cf, ngx_http_core_module);if (cmcf->ports == NULL) {cmcf->ports = ngx_array_create(cf->temp_pool, 2,sizeof(ngx_http_conf_port_t));if (cmcf->ports == NULL) {return NGX_ERROR;}}初始化ngx_http_core_main_conf_t中的ports數(shù)組。sa = &lsopt->u.sockaddr;switch (sa->sa_family) {#if (NGX_HAVE_INET6)case AF_INET6:sin6 = &lsopt->u.sockaddr_in6;p = sin6->sin6_port;break; #endif#if (NGX_HAVE_UNIX_DOMAIN)case AF_UNIX:p = 0;break; #endifdefault: /* AF_INET */sin = &lsopt->u.sockaddr_in;p = sin->sin_port;break;}接下來(lái)，獲取監(jiān)聽(tīng)socket的端口信息和地址信息。port = cmcf->ports->elts;for (i = 0; i < cmcf->ports->nelts; i++) {if (p != port[i].port || sa->sa_family != port[i].family) {continue;}/* a port is already in the port list */return ngx_http_add_addresses(cf, cscf, &port[i], lsopt);}

????????這段代碼是遍歷ports數(shù)組，查看新添加的端口信息是否已經(jīng)存在，如果該端口信息存在則調(diào)用ngx_http_add_addresses函數(shù)在對(duì)應(yīng)的端口結(jié)構(gòu)上添加地址信息。否則，在prots數(shù)組中添加一個(gè)元素，并初始化，然后調(diào)用ngx_http_add_address函數(shù)添加地址信息。
? ?

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);

????????
????????下面先看一下ngx_http_add_addresses函數(shù)如何在存在對(duì)應(yīng)port的情況下的添加地址信息。

????????4. ngx_http_add_addresses

? ?

sa = &lsopt->u.sockaddr;switch (sa->sa_family) { #if (NGX_HAVE_INET6)case AF_INET6:off = offsetof(struct sockaddr_in6, sin6_addr);len = 16;break; #endif #if (NGX_HAVE_UNIX_DOMAIN)case AF_UNIX:off = offsetof(struct sockaddr_un, sun_path);len = sizeof(saun->sun_path);break; #endifdefault: /* AF_INET */off = offsetof(struct sockaddr_in, sin_addr);len = 4;break;}

????????這段代碼是確定具體協(xié)議類型的地址信息在地址結(jié)構(gòu)中的偏移量和長(zhǎng)度，因?yàn)椴荒鼙容^整個(gè)地址結(jié)構(gòu)。
? ?

p = lsopt->u.sockaddr_data + off;addr = port->addrs.elts;/*** 在port的addr數(shù)組中已經(jīng)存在該地址時(shí)，直接將ngx_http_core_srv_conf_t* 結(jié)構(gòu)添加到到addr對(duì)應(yīng)的servers數(shù)組中。*/for (i = 0; i < port->addrs.nelts; i++) {// 比較地址是否相同if (ngx_memcmp(p, addr[i].opt.u.sockaddr_data + off, len) != 0) {continue;}/* the address is already in the address list *//*** 向ngx_http_conf_addr_t的servers數(shù)組添加ngx_http_core_srv_conf_t結(jié)構(gòu)*/if (ngx_http_add_server(cf, cscf, &addr[i]) != NGX_OK) {return NGX_ERROR;}/* 設(shè)置default_server屬性 *//* 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; #endifif (lsopt->set) {if (addr[i].opt.set) {ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,"a 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; #endifreturn NGX_OK;}

????????如果port對(duì)應(yīng)的addrs數(shù)組中已經(jīng)存在要添加的地址對(duì)應(yīng)的ngx_http_conf_addr_t結(jié)構(gòu)，那么直接向addr添加server塊的配置信息。接下來(lái)的代碼處理port的addrs數(shù)組中不存在對(duì)應(yīng)地址的情況，只是很簡(jiǎn)單的調(diào)用ngx_http_add_address函數(shù)，它的功能就是向port的addrs數(shù)組添加元素，具體看一下這個(gè)函數(shù)。
????????5. ngx_http_add_address

? ?

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;}}很簡(jiǎn)單，如果port的addrs數(shù)組沒(méi)有初始化，那么對(duì)其初始化。addr = ngx_array_push(&port->addrs);if (addr == NULL) {return NGX_ERROR;}接下來(lái)向addrs添加一個(gè)元素。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;?? ?// 對(duì)于此addr:port，該server block是默認(rèn)的addr->servers.elts = NULL;

????????對(duì)新添加的元素初始化，會(huì)將第一個(gè)監(jiān)聽(tīng)addr:port信息的server塊作為default server，后續(xù)添加的監(jiān)聽(tīng)addr:port的server塊通過(guò)listen指令，并包含default_server選項(xiàng)可以修改監(jiān)聽(tīng)addr:port的default server。
? ?

return ngx_http_add_server(cf, cscf, addr);

????????最后，調(diào)用ngx_http_add_server將該server塊的server config添加到addr的servers數(shù)組中，這個(gè)函數(shù)邏輯很簡(jiǎn)單，首先檢查是否存在重復(fù)的server config，如果存在則報(bào)錯(cuò)，否則添加一個(gè)新的元素。
????????通過(guò)上面這些函數(shù)的調(diào)用完成了配置信息的存儲(chǔ)，下面看一下ngx_listening_t的初始化。

（2）初始化監(jiān)聽(tīng)socket（ngx_listening_t）
????????在http模塊初始化中，我們介紹了在函數(shù)ngx_http_block函數(shù)中調(diào)用ngx_http_optimize_servers函數(shù)完成ngx_listening_t初始化，下面看一下這個(gè)函數(shù)的實(shí)現(xiàn)。
????????1. ngx_http_optimize_servers

? ?

port = ports->elts;for (p = 0; p < ports->nelts; p++) {/*** 將addrs排序，帶通配符的地址排在后面*/ngx_sort(port[p].addrs.elts, (size_t) port[p].addrs.nelts,sizeof(ngx_http_conf_addr_t), ngx_http_cmp_conf_addrs);/** check whether all name-based servers have the same* configuraiton as a default server for given address:port*/addr = port[p].addrs.elts;for (a = 0; a < port[p].addrs.nelts; a++) {if (addr[a].servers.nelts > 1 #if (NGX_PCRE)|| addr[a].default_server->captures #endif){/*** 初始addr(ngx_http_conf_addr_t)中的hash、wc_head和wc_tail哈希表。* 這些哈希表以server name（虛擬主機(jī)名）為key，server塊的ngx_http_core_srv_conf_t為* value，用于在處理請(qǐng)求時(shí)，根據(jù)請(qǐng)求的host請(qǐng)求行快速找到處理該請(qǐng)求的server配置結(jié)構(gòu)。*/if (ngx_http_server_names(cf, cmcf, &addr[a]) != NGX_OK) {return NGX_ERROR;}}}/*** 初始化ngx_listening_t*/if (ngx_http_init_listening(cf, &port[p]) != NGX_OK) {return NGX_ERROR;}}

????????這個(gè)函數(shù)就是遍歷所有的端口號(hào)，將端口號(hào)對(duì)應(yīng)的地址結(jié)構(gòu)的hash、wc_head和wc_tail初始化，這個(gè)在初始化后面的ngx_listening_t的servers字段時(shí)會(huì)用到。然后調(diào)用ngx_http_init_listening函數(shù)完成ngx_listening_t初始化。
????????2. ngx_http_init_listening

?

? while (i < last) {if (bind_wildcard && !addr[i].opt.bind) {i++;continue;}/*** 添加ngx_listening_t*/ls = ngx_http_add_listening(cf, &addr[i]);if (ls == NULL) {return NGX_ERROR;}hport = ngx_pcalloc(cf->pool, sizeof(ngx_http_port_t));if (hport == NULL) {return NGX_ERROR;}/*** servers會(huì)用來(lái)保存虛擬主機(jī)的信息，在處理請(qǐng)求時(shí)會(huì)賦值給request* 用于進(jìn)行虛擬主機(jī)的匹配*/ls->servers = hport;if (i == last - 1) {hport->naddrs = last;} else {hport->naddrs = 1;i = 0;}/* 初始化ngx_http_virtual_names_t */switch (ls->sockaddr->sa_family) { #if (NGX_HAVE_INET6)case AF_INET6:if (ngx_http_add_addrs6(cf, hport, addr) != NGX_OK) {return NGX_ERROR;}break; #endifdefault: /* AF_INET */if (ngx_http_add_addrs(cf, hport, addr) != NGX_OK) {return NGX_ERROR;}break;}addr++;last--;}

????????遍歷port的addrs數(shù)組，因?yàn)槊總€(gè)ngx_http_conf_addr_t有opt屬性，也就是ngx_listening_t的配置信息，這里會(huì)調(diào)用ngx_http_add_listening函數(shù)創(chuàng)建ngx_listening_t并添加到ngx_cycle_t中。ngx_http_add_addrs函數(shù)用于初始化ls->servers，這個(gè)屬性主要是存放該監(jiān)聽(tīng)socket對(duì)應(yīng)的虛擬主機(jī)的信息，在處理請(qǐng)求時(shí)根據(jù)請(qǐng)求行的host匹配，選擇對(duì)應(yīng)的一個(gè)server塊的ngx_http_core_srv_conf_t結(jié)構(gòu)，這個(gè)結(jié)構(gòu)里存放了剛請(qǐng)求處理的全局配置信息。下面看一下ngx_http_add_listening函數(shù)。
????????3. ngx_http_add_listening

? ? ls = ngx_create_listening(cf, &addr->opt.u.sockaddr, addr->opt.socklen);if (ls == NULL) {return NULL;}

????????調(diào)用ngx_create_listening函數(shù)創(chuàng)建ngx_listening_t，這個(gè)函數(shù)的內(nèi)容在下面分析。

? ? // 設(shè)置監(jiān)聽(tīng)socket的handler，在監(jiān)聽(tīng)到新的連接時(shí)調(diào)用，即ngx_event_accept中。ls->handler = ngx_http_init_connection;

????????設(shè)置ngx_listening_t的handler，這個(gè)handler會(huì)在監(jiān)聽(tīng)到客戶端連接時(shí)被調(diào)用，具體就是在ngx_event_accept函數(shù)中，ngx_http_init_connection函數(shù)顧名思義，就是初始化這個(gè)新建的連接。后面的代碼就是根據(jù)addr的opt屬性初始化創(chuàng)建的ngx_listening_t結(jié)構(gòu)。下面看一下ngx_http_create_listengint函數(shù)。
????????4. ngx_http_create_listening

? ?

ls = ngx_array_push(&cf->cycle->listening);if (ls == NULL) {return NULL;}首先向ngx_cycle_t的listenging數(shù)組添加一個(gè)元素。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, text, NGX_SOCKADDR_STRLEN, 1);ls->addr_text.len = len;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);配置地址信息，包括二進(jìn)制地址和文本格式地址。ls->fd = (ngx_socket_t) -1;ls->type = SOCK_STREAM;ls->backlog = NGX_LISTEN_BACKLOG;ls->rcvbuf = -1;ls->sndbuf = -1;#if (NGX_HAVE_SETFIB)ls->setfib = -1; #endif

????????對(duì)屬性設(shè)置默認(rèn)值。
（3） ?打開(kāi)并配置監(jiān)聽(tīng)socket
????????在nginx啟動(dòng)過(guò)程中，介紹過(guò)在ngx_init_cycle函數(shù)中，會(huì)調(diào)用ngx_open_listening_sockets和ngx_configure_listening_sockets函數(shù)完成監(jiān)聽(tīng)socket的打開(kāi)和配置，下面具體看一下這兩函數(shù)。
????????1. 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; #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) {continue;}/*** 已經(jīng)從就cycle處繼承該socket，不需重新打開(kāi)*/if (ls[i].fd != -1) {continue;}if (ls[i].inherited) {/* TODO: close on exit *//* TODO: nonblocking *//* TODO: deferred accept */continue;}/* 新建一個(gè)socket，socket(地址結(jié)構(gòu)的協(xié)議族，socket類型tcp/udp，)*/s = ngx_socket(ls[i].sockaddr->sa_family, ls[i].type, 0);if (s == -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_HAVE_INET6 && defined IPV6_V6ONLY)if (ls[i].sockaddr->sa_family == AF_INET6 && ls[i].ipv6only) {int ?ipv6only;ipv6only = (ls[i].ipv6only == 1);if (setsockopt(s, IPPROTO_IPV6, IPV6_V6ONLY,(const void *) &ipv6only, sizeof(int))== -1){ngx_log_error(NGX_LOG_EMERG, log, ngx_socket_errno,"setsockopt(IPV6_V6ONLY) %V failed, ignored",&ls[i].addr_text);}} #endif/* TODO: close on exit */if (!(ngx_event_flags & NGX_USE_AIO_EVENT)) {/* 將socket設(shè)置為非阻塞 */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;}}ngx_log_debug2(NGX_LOG_DEBUG_CORE, log, 0,"bind() %V #%d ", &ls[i].addr_text, s);/* 將socket綁定到要監(jiān)聽(tīng)的地址 */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;}#if (NGX_HAVE_UNIX_DOMAIN)/* 處理unix domain socket */if (ls[i].sockaddr->sa_family == AF_UNIX) {mode_t ? mode;u_char ?*name;name = ls[i].addr_text.data + sizeof("unix:") - 1;mode = (S_IRUSR|S_IWUSR|S_IRGRP|S_IWGRP|S_IROTH|S_IWOTH);if (chmod((char *) name, mode) == -1) {ngx_log_error(NGX_LOG_EMERG, cycle->log, ngx_errno,"chmod() \"%s\" failed", name);}if (ngx_test_config) {if (ngx_delete_file(name) == -1) {ngx_log_error(NGX_LOG_EMERG, cycle->log, ngx_errno,ngx_delete_file_n " %s failed", name);}}} #endif/* 將socket轉(zhuǎn)換為監(jiān)聽(tīng)socket，backlog指定了內(nèi)核為改監(jiān)聽(tīng)socket排隊(duì)的最大值 */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;}/* 標(biāo)識(shí)是監(jiān)聽(tīng)socket */ls[i].listen = 1;/* 設(shè)置ngx_listening_t的描述符 */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; }

????????這個(gè)函數(shù)就是打開(kāi)socket，和一般socket編程一樣，就是調(diào)用socket、bind和listen，具體看一下注釋。
????????2. ngx_configure_listening_sockets

void ngx_configure_listening_sockets(ngx_cycle_t *cycle) {ngx_uint_t ? ? ? ? ? ? ? ? i;ngx_listening_t ? ? ? ? ? *ls;#if (NGX_HAVE_DEFERRED_ACCEPT && defined SO_ACCEPTFILTER)struct accept_filter_arg ? af; #endif #if (NGX_HAVE_DEFERRED_ACCEPT && defined TCP_DEFER_ACCEPT)int ? ? ? ? ? ? ? ? ? ? ? ?timeout; #endifls = cycle->listening.elts;for (i = 0; i < cycle->listening.nelts; i++) {ls[i].log = *ls[i].logp;/*** 設(shè)置監(jiān)聽(tīng)socket的接收緩沖區(qū)大小*/if (ls[i].rcvbuf != -1) {if (setsockopt(ls[i].fd, SOL_SOCKET, SO_RCVBUF,(const void *) &ls[i].rcvbuf, sizeof(int))== -1){ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_socket_errno,"setsockopt(SO_RCVBUF, %d) %V failed, ignored",ls[i].rcvbuf, &ls[i].addr_text);}}/*** 設(shè)置監(jiān)聽(tīng)socket的發(fā)送緩沖區(qū)大小*/if (ls[i].sndbuf != -1) {if (setsockopt(ls[i].fd, SOL_SOCKET, SO_SNDBUF,(const void *) &ls[i].sndbuf, sizeof(int))== -1){ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_socket_errno,"setsockopt(SO_SNDBUF, %d) %V failed, ignored",ls[i].sndbuf, &ls[i].addr_text);}}#if (NGX_HAVE_SETFIB)if (ls[i].setfib != -1) {if (setsockopt(ls[i].fd, SOL_SOCKET, SO_SETFIB,(const void *) &ls[i].setfib, sizeof(int))== -1){ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_socket_errno,"setsockopt(SO_SETFIB, %d) %V failed, ignored",ls[i].setfib, &ls[i].addr_text);}} #endif#if 0if (1) {int tcp_nodelay = 1;if (setsockopt(ls[i].fd, IPPROTO_TCP, TCP_NODELAY,(const void *) &tcp_nodelay, sizeof(int))== -1){ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_socket_errno,"setsockopt(TCP_NODELAY) %V failed, ignored",&ls[i].addr_text);}} #endifif (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);}}/** setting deferred mode should be last operation on socket,* because code may prematurely continue cycle on failure*/#if (NGX_HAVE_DEFERRED_ACCEPT)#ifdef SO_ACCEPTFILTERif (ls[i].delete_deferred) {/*** set accept filter on listening socket* 將SO_ACCEPTFILTER設(shè)置為NULL，也就是刪除accept filter*/if (setsockopt(ls[i].fd, SOL_SOCKET, SO_ACCEPTFILTER, NULL, 0)== -1){ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_errno,"setsockopt(SO_ACCEPTFILTER, NULL) ""for %V failed, ignored",&ls[i].addr_text);if (ls[i].accept_filter) {ngx_log_error(NGX_LOG_ALERT, cycle->log, 0,"could not change the accept filter ""to \"%s\" for %V, ignored",ls[i].accept_filter, &ls[i].addr_text);}continue;}ls[i].deferred_accept = 0;}if (ls[i].add_deferred) {ngx_memzero(&af, sizeof(struct accept_filter_arg));(void) ngx_cpystrn((u_char *) af.af_name,(u_char *) ls[i].accept_filter, 16);/*** set accept filter on listening socket* 將SO_ACCEPTFILTER設(shè)置為ls[i].accept_filter，也就是添加accept filter*/if (setsockopt(ls[i].fd, SOL_SOCKET, SO_ACCEPTFILTER,&af, sizeof(struct accept_filter_arg))== -1){ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_errno,"setsockopt(SO_ACCEPTFILTER, \"%s\") "" for %V failed, ignored",ls[i].accept_filter, &ls[i].addr_text);continue;}ls[i].deferred_accept = 1;}#endif#ifdef TCP_DEFER_ACCEPTif (ls[i].add_deferred || ls[i].delete_deferred) {if (ls[i].add_deferred) {timeout = (int) (ls[i].post_accept_timeout / 1000);} else {timeout = 0;}if (setsockopt(ls[i].fd, IPPROTO_TCP, TCP_DEFER_ACCEPT,&timeout, sizeof(int))== -1){ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_errno,"setsockopt(TCP_DEFER_ACCEPT, %d) for %V failed, ""ignored",timeout, &ls[i].addr_text);continue;}}if (ls[i].add_deferred) {ls[i].deferred_accept = 1;}#endif#endif /* NGX_HAVE_DEFERRED_ACCEPT */}return; }

????????這個(gè)函數(shù)就是根據(jù)配置調(diào)用setsockopt函數(shù)設(shè)置socket選項(xiàng)，比如接收緩沖區(qū)、發(fā)送緩沖區(qū)等，具體也沒(méi)有什么可講的。
????????通過(guò)這3個(gè)步驟就完成了監(jiān)聽(tīng)socket的初始化，接下來(lái)就會(huì)在ngx_event_process_init函數(shù)（ngx_event_core_moduel的process_init回調(diào)函數(shù)，在創(chuàng)建完worker進(jìn)程后調(diào)用）中將這些監(jiān)聽(tīng)socket添加到事件循環(huán)中。

---------------------?
作者：chosen0ne?
來(lái)源：CSDN?
原文：https://blog.csdn.net/chosen0ne/article/details/7754608?
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