瑕佸垱寤轰竴涓彲鐢ㄧ殑濂楁帴瀛楋紝闇瑕佷娇鐢ㄤ笅闈㈢殑鍑芥暟
int socket(int domain, int type, int protocol)
domain灏辨槸鎸嘝F_INET,PF_INET6浠ュ強PF_LOCAL绛夛紝琛ㄧず浠涔堟牱鐨勫鎺ュ瓧
type鍙敤鐨勫兼槸锛
– SOCK_STREAM:琛ㄧず鐨勬槸瀛楄妭娴侊紝瀵瑰簲tcp
– SOCK_DGRAM: 琛ㄧず鐨勬槸鏁版嵁鎶ワ紝瀵瑰簲udp
– SOCK_RAW:琛ㄧず鐨勬槸鍘熷濂楁帴瀛
鍙傛暟protocol鍘熸湰鏄敤鏉ユ寚瀹氶氫俊鍗忚鐨勶紝鐜板湪鍩烘湰搴熷純銆傚洜涓哄崗璁凡缁忛氳繃鍓嶉潰涓や釜鍙傛暟鎸囧畾瀹屾垚锛屾墍浠ュ啓0灏辫銆
鍒涘缓鍑烘潵鐨勫鎺ュ瓧濡傛灉闇瑕佽鍒汉浣跨敤锛屽氨闇瑕佽皟鐢╞ind鍑芥暟鎶婂鎺ュ瓧鍜屽鎺ュ瓧鍦板潃缁戝畾銆
bind(int fd, sockaddr * addr, socklen_t len)
bind绗簩涓弬鏁版槸閫氱敤鍦板潃sockaddraddr,杩欓噷鏈変竴涓湴鏂瑰煎緱娉ㄦ剰锛岄偅灏辨槸铏界劧鎺ユ敹鐨勬槸閫氱敤鍦板潃鏍煎紡锛屽疄闄呬笂浼犲叆鐨勫弬鏁板彲鑳芥槸ipv4锛宨pv6鎴栬呮湰鍦板鎺ュ瓧鏍煎紡銆傛牴鎹甽en瀛楁鍒ゆ柇浼犲叆鐨刟ddr璇ユ庝箞瑙ｆ瀽锛宭en瀛楁琛ㄧず鐨勬槸浼犲叆鐨勫湴鍧闀垮害锛屽畠鏄竴涓彲鍙樺笺
鍙互鐞嗚В涓
bind(int fd, void * addr, socklen_t len)
涓嶈繃bsd璁捐濂楁帴瀛楀ぇ绾︽槸1982骞达紝閭ｄ釜鏃跺檆璇█杩樻病鏈塿oid鐨勬敮鎸併備负浜嗚В鍐宠繖涓棶棰橈紝BSD鐨勮璁¤呬滑鍒涘缓鎬х殑璁捐浜嗛氱敤鍦板潃鏍煎紡鏉ヤ綔涓烘敮鎸乥ind鍜宎ccept绛夎繖浜涘嚱鏁扮殑鍙傛暟銆
瀵逛簬浣跨敤鑰呮潵璇达紝姣忔寰愬▍灏唅pv4锛宨pv6鎴栬呮湰鍦板鎺ュ瓧杞寲涓洪氱敤濂楁帴瀛楁牸寮忥紝灏卞儚甯岃繄绾崇殑ipv4濂楁帴瀛楀湴鍧鏍煎紡鐨勪緥瀛愪竴鏍凤細
struct sockaddr_in name;
bind (sock, (struct sockaddr *) &name, sizeof (name)
瀵逛簬瀹炵幇鑰呮潵璇达紝鍙牴鎹鍦板潃鐨勫墠涓や釜瀛楄妭鍒ゆ柇鍑烘槸鍝鍦板潃锛屼负浜嗗鐞嗛暱搴﹀彲鍙樼殑缁撴瀯锛岄渶瑕佽鍙栧嚱鏁扮殑绗笁涓弬鏁帮紝涔熷氨鏄痩en瀛楁銆
鎴戜滑鍙互鎶婂湴鍧璁剧疆鎴愭湰鍦扮殑ip鍦板潃锛岃繖鐩稿綋浜庡憡璇夋搷浣滅郴缁熷唴鏍革紝浠呬粎瀵圭洰鏍噄p鏄湰鏈篿p鍦板潃鐨刬p鍖呰繘琛屽鐞嗭紝閫氳繃缁熼厤鍦板潃鐨勮缃
瀵逛簬ipv4鐨勫湴鍧鏉ヨ锛屼娇鐢╥naddr_any鏉ュ畬鎴愮粺閰嶅湴鍧鐨勮缃
瀵逛簬ipv6鐨勫湴鍧鏉ヨ锛屼娇鐢╥n6addr_any鏉ュ畬鎴愮粺閰嶅湴鍧鐨勮缃
struct sockaddr_in name;
name.sin_addr.s_addr = htonl (INADDR_ANY); /* IPV4 閫氶厤鍦板潃 */
闄や簡鍦板潃锛岃繕鏈夌鍙ｏ紝濡傛灉鎶婄鍙ｈ缃负0锛屽氨鐩稿綋浜庢妸绔彛鐨勬帶鍒舵潈浜ょ粰鎿嶄綔绯荤粺鍐呮牳鏉ュ鐞嗭紝鎿嶄綔绯荤粺鍐呮牳浼氭牴鎹竴瀹氱殑绠楁硶閫夋嫨涓涓┖闂茬殑绔彛锛屽畬鎴愬鎺ュ瓧鐨勭粦瀹氥
涓涓猧pv4 tcp濂楁帴瀛楃殑渚嬪瓙
#include <stdio.h>
#include <stdlib.h>
#include <sys/socket.h>
#include <netinet/in.h>
int make_socket (uint16_t port)
{
int sock;
struct sockaddr_in name;
/* 鍒涘缓瀛楄妭娴佺被鍨嬬殑 IPV4 socket. */
sock = socket (PF_INET, SOCK_STREAM, 0);
if (sock < 0)
{
perror ("socket");
exit (EXIT_FAILURE);
}
/* 缁戝畾鍒 port 鍜 ip. */
name.sin_family = AF_INET; /* IPV4 */
name.sin_port = htons (port); /* 鎸囧畾绔彛 */
name.sin_addr.s_addr = htonl (INADDR_ANY); /* 閫氶厤鍦板潃 */
/* 鎶 IPV4 鍦板潃杞崲鎴愰氱敤鍦板潃鏍煎紡锛屽悓鏃朵紶閫掗暱搴 */
if (bind (sock, (struct sockaddr *) &name, sizeof (name)) < 0)
{
perror ("bind");
exit (EXIT_FAILURE);
}
return sock
}
鍒濆鍖栧垱寤虹殑濂楁帴瀛楋紝鍙互璁や负鏄竴涓”涓诲姩”濂楁帴瀛楋紝鍏剁洰鐨勬槸涔嬪悗涓诲姩鍙戣捣璇锋眰(閫氳繃璋冪敤connect鍑芥暟)锛岄氳繃listen鍑芥暟锛屽彲浠ュ皢鍘熸潵鐨”涓诲姩”濂楁帴瀛楄浆鎹负”琚姩”濂楁帴瀛楋紝鍛婅瘔鎿嶄綔绯荤粺鍐呮牳浼歩涓烘鍋氬ソ鎺ュ彈鐢ㄦ埛璇锋眰鐨勪竴鍒囧噯澶囷紝姣斿瀹屾垚杩炴帴闃熷垪銆
listen鍑芥暟
int listen (int socketfd, int backlog)
绗竴涓弬鏁皊ocketfd涓哄鎺ュ瓧鎻忚堪绗,绗簩涓弬鏁癰acklog锛屽畼鏂圭殑瑙ｉ噴涓烘湭瀹屾垚杩炴帴闃熷垪鐨勫ぇ灏忥紝杩欎釜鍙傛暟鐨勫ぇ灏忓喅瀹氫簡鍙互鎺ユ敹鐨勫苟鍙戞暟鐩紝杩欎釜鍙傛暟瓒婂ぇ锛屽苟鍙戞暟鐩悊璁轰笂涔熶細瓒婂ぇ锛屼絾鏄弬鏁拌繃澶т篃浼氬崰鐢ㄨ繃澶氱殑绯荤粺璧勬簮锛屼竴浜涚郴缁燂紝姣斿linux骞朵笉杩愯瀵硅繖涓弬鏁拌繘琛屾敼鍙橈紝瀵逛簬backlog鏁翠釜鍙傛暟鐨勮缃湁涓浜涙渶浣冲疄璺点
濂芥瘮鏈変汉鎵撶數璇濊繃鏉ワ紝闇瑕佹嬁璧疯瘽绛掑紑濮嬪簲绛斻
浣滅敤灏辨槸杩炴帴寤虹珛涔嬪悗锛屾搷浣滅郴缁熷唴鏍稿拰搴旂敤绋嬪簭涔嬮棿鐨勬ˉ姊
int accept(int listensockfd, struct sockaddr *cliaddr, socklen_t *addrlen)
杩欓噷涓瀹氳娉ㄦ剰鏈変袱涓鎺ュ瓧鎻忚堪瀛楋紝绗竴涓槸鐩戝惉濂楁帴瀛楁弿杩板瓧listensockfd,瀹冩槸浣滀负杈撳叆鍙傛暟瀛樺湪鐨勶紱绗簩涓槸杩斿洖鐨勫凡杩炴帴濂楁帴瀛楁弿杩板瓧銆
鍓嶉潰璁茶堪鐨刡ind锛宭isten浠ュ強accept鐨勮繃绋嬶紝鏄吀鍨嬬殑鏈嶅姟鍣ㄧ鐨勮繃绋嬨
绗竴姝ヨ繕鏄竴鏍凤紝寤虹珛涓涓鎺ュ瓧銆備笉涓鏍风殑鏄
瀹㈡埛绔拰鏈嶅姟鍣ㄧ鐨勮繛鎺ュ缓绔嬶紝鏄氳繃connect鍑芥暟瀹屾垚鐨
int connect(int sockfd, const struct sockaddr *servaddr, socklen_t addrlen)
鍑芥暟鐨勭涓涓弬鏁皊ockfd鏄繛鎺ュ鎺ュ瓧锛岄氳繃鍓嶉潰璁茶堪鐨剆ocket鍑芥暟鍒涘缓銆傜浜屼釜锛岀涓変釜鍙傛暟servaddr鍜宎ddrlen鍒嗗埆浠ｈ〃鎸囧悜濂楁帴瀛楀湴鍧缁撴瀯鐨勬寚閽堝拰璇ョ粨鏋勭殑澶у皬銆傚鎺ュ瓧鍦板潃缁撴瀯蹇呴』鍚湁鏈嶅姟鍣ㄧ殑ip鍦板潃鍜岀鍙ｅ彿銆
瀹㈡埛鍦ㄨ皟鐢ㄥ嚱鏁癱onnect鍓嶄笉蹇呴潪寰楄皟鐢╞ind鍑芥暟锛屽洜涓哄鏋滈渶瑕佺殑璇濓紝鍐呮牳浼氱‘瀹氭簮ip鍦板潃锛屽苟鎸夌収涓瀹氱殑绠楁硶閫夋嫨涓涓复鏃剁鍙ｆ墍璋撴簮绔彛銆
濡傛灉鏄痶cp濂楁帴瀛楋紝閭ｄ箞璋冪敤connect鍑芥暟灏嗘縺鍙憈cp鐨勪笁娆℃彙鎵嬭繃绋嬶紝鑰屼笖浠呭湪杩炴帴寤虹珛鎴愬姛鎴栧嚭閿欐墠杩斿洖銆
鍏朵腑鍑洪敊杩斿洖鍙兘鏈変互涓嬪嚑绉嶆儏鍐碉細
1. 涓夋鎻℃墜鏃犳硶寤虹珛锛屽鎴风鍙戝嚭鐨剆yn鍖呮病鏈変换浣曠浉搴旓紝浜庢槸杩斿洖timeout閿欒锛岃繖绉嶆儏鍐垫瘮杈冨父瑙佺殑鍘熷洜鏄搴旂殑鏈嶅姟绔痠p鍐欓敊銆
2. 瀹㈡埛绔敹鍒颁簡RST(澶嶄綅)鍥炵瓟锛岃繖鏃跺欏鎴风浼氱珛鍗宠繑鍥瀋onnection refused閿欒銆傝繖寮犳儏鍐垫瘮杈冨父瑙佷簬瀹㈡埛绔彂閫佽繛鎺ヨ姹傛椂鐨勮姹傜鍙ｅ啓閿欙紝鍥犱负RST鏄痶cp鍦ㄥ彂鐢熼敊璇椂鍙戦佺殑涓绉峵cp鍒嗚妭銆備骇鐢烺ST鐨勪笁涓潯浠舵槸锛氱洰鐨勫湴涓烘煇绔彛鐨凷YN鍒拌揪锛岀劧鑰岃绔彛涓婃病鏈夋鍦ㄧ洃鍚殑鏈嶅姟鍣(濡傚墠鎵杩)锛汿CP鎯冲彇娑堜竴涓凡鏈夎繛鎺ワ紱TCP鎺ユ敹鍒颁竴涓牴鏈笉瀛樺湪鐨勮繛鎺ヤ笂鐨勫垎鑺傘
3. 瀹㈡埛鍙戝嚭鐨凷YN鍖呭湪缃戠粶涓婂紩璧蜂簡”destination unreachable”,鍗崇洰鐨勪笉鍙揪鐨勯敊璇紝杩欑鎯呭喌姣旇緝甯歌鐨勫師鍥犳槸瀹㈡埛绔拰鏈嶅姟绔矾鐢变笉鍚屻
瀹㈡埛绔 鏈嶅姟鍣
socket,connect(闃诲)(涓诲姩鎵撳紑)SYN_SENT SYN j socket,bind,listen(琚姩鎵撳紑)accept(闃诲)SYN_RCVD SYN k,ACK j+1
connect杩斿洖 ESTABLISED ACK k+1 accept杩斿洖 read闃诲 ESTABLISED
闃诲寮忥紝灏辨槸璋冪敤鍙戣捣鍚庝笉浼氱洿鎺ヨ繑鍥烇紝鍙堟搷浣滅郴缁熷唴鏍稿鐞嗕箣鍚庢墠浼氳繑鍥烇紝鐩稿鐨勶紝杩樻湁涓绉嶅彨鍋氶潪闃诲寮忕殑銆
涓寮濮嬫湇鍔″櫒閫氳繃socket, bind鍜宭isten瀹屾垚浜嗚鍔ㄥ鎺ュ瓧鐨勫噯澶囧伐浣滐紝琚姩鐨勬剰鎬濆氨鏄瓑鐫鍒汉鏉ヨ繛鎺ワ紝鐒朵箮璋冪敤accept锛屾晳鎶ら樆濉炲湪杩欓噷锛岀瓑寰呭鎴风鐨勮繛鎺ユ潵涓达紱瀹㈡埛绔氳繃socket鍜宑onnect鍑芥暟涔嬪悗锛屼篃浼氶樆濉炪傛帴涓嬫潵鐨勪簨鎯呮槸鐢辨搷浣滅郴缁熷唴鏍稿畬鎴愶紝鏇村叿浣撶殑鏉ヨ锛屾槸鎿嶄綔绯荤粺鍐呮牳缃戠粶鍗忚鏍堝湪宸ヤ綔銆
1. 瀹㈡埛绔殑鍗忚鏍堝悜鏈嶅姟鍣ㄧ鍙戦佷簡SYN鍖咃紝骞跺憡璇夋湇鍔″櫒绔綋鍓嶅彂閫佸簭鍒楀彿j锛屽鎴风杩涘叆SYNC_SENT鐘舵侊紱
2. 鏈嶅姟鍣ㄧ鐨勫崗璁爤鏀跺埌杩欎釜鍖呬箣鍚庯紝鍜屽鎴风杩涜ACK搴旂瓟锛屽簲绛旂殑鍊间负j+1锛岃〃绀哄SYN鍖卝鐨勭‘璁わ紝鍚屾椂鏈嶅姟鍣ㄤ篃鍙戦佷竴涓猄YN鍖咃紝鍛婅瘔瀹㈡埛绔綋鍓嶆垜鐨勫彂閫佸簭鍒楀彿涓簁锛屾湇鍔″櫒绔繘鍏YNC_RCVD鐘舵侊紱
3. 瀹㈡埛绔崗璁爤鏀跺埌ACK涔嬪悗锛屼娇寰楀簲鐢ㄧ▼搴忎粠connect璋冪敤杩斿洖锛岃〃绀哄鎴风鍒版湇鍔″櫒绔殑鍗曞悜杩炴帴寤虹珛鎴愬姛锛屽鎴风鐨勭姸鎬佷负ESTABLISHED锛屽悓鏃跺鎴风鍗忚鏍堜篃浼氬鏈嶅姟鍣ㄧ鐨凷YN鍖呰繘琛屽簲绛旓紝搴旂瓟鏁版嵁涓簁+1锛
4. 搴旂瓟鍖呰揪鍒版湇鍔″櫒绔悗锛屾湇鍔″櫒绔崗璁爤浣垮緱accept闃诲璋冪敤杩斿洖锛岃繖涓椂鍊欐湇鍔″櫒绔埌瀹㈡埛绔殑鍗曞悜杩炴帴涔熷缓绔嬫垚鍔燂紝鏈嶅姟鍣ㄧ涔熻繘鍏STRABLISHED鐘舵併
鍙戣〃鍥炲