计算机网络:TCP
TCP與UDP的比較?
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?創建tcp套接字
#include<stdio.h> #include<stdlib.h> #include<sys/types.h> #include<sys/socket.h>int main(int argc, char const * argv[]){int sockfd;// 創建tcp套接字if((sockfd=socket(AF_INET,SOCK_STREAM,0)) == -1){perror("fail to socket");exit(1);}printf("sockfd=%d\n", sockfd);return 0; }?tcp客戶端
#include<stdlib.h> #include<stdio.h> #include<string.h> #include<sys/types.h> #include<sys/socket.h> #include<arpa/inet.h> #include<netinet/in.h> #include<unistd.h>#define N 128 int main(int argc, char const * argv[]){if(argc < 3){fprintf(stderr, "Usage:%s ip port\n",argv[0]);exit(1);}int sockfd;// 創建tcp套接字if((sockfd=socket(AF_INET,SOCK_STREAM,0)) == -1){perror("fail to socket");exit(1);}struct sockaddr_in serveraddr;socklen_t addrlen = sizeof(serveraddr);serveraddr.sin_family = AF_INET; // 協議族 AF_INET:ipv4網絡協議// inet_addr: 將點分十進制字符串ip地址轉為整形數據serveraddr.sin_addr.s_addr = inet_addr(argv[1]); // ip地址// atoi 將數字型字符串轉換為整形數據// htons 將主機字節序轉化為網絡字節序serveraddr.sin_port = htons(atoi(argv[2]));// 主動跟服務器建立鏈接if(connect(sockfd,(struct sockaddr*)&serveraddr, addrlen) == -1){perror("fail to connect");exit(1);};char buf[N] = "";while(1){// 讀取終端輸入的數據到buf中fgets(buf,N,stdin);//發送buf數據if(send(sockfd,buf,sizeof(buf),0)==-1){perror("fail to send");exit(1);}}printf("sockfd=%d\n", sockfd);return 0; }?使用網絡調試助手作為tcp服務器
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?tcp服務器(tcp原本不是并發服務器,同一時間只能與一個客戶端通信)
? ?tcp不能并發的原因: 由于服務器端有兩個阻塞函數,accept和recv,兩個函數需要先后運行。所以導致運行一個函數的時候,另一個函數無法執行。無法保證一邊連接客戶端,一邊與其他客戶端通信。
#include<stdlib.h> #include<stdio.h> #include<string.h> #include<sys/types.h> #include<sys/socket.h> #include<arpa/inet.h> #include<netinet/in.h> #include<unistd.h>#define N 128 int main(int argc, char const * argv[]){if(argc < 3){fprintf(stderr, "server Usage:%s ip port\n",argv[0]);exit(1);}int sockfd;// 創建tcp套接字if((sockfd=socket(AF_INET,SOCK_STREAM,0)) == -1){perror("fail to socket");exit(1);}struct sockaddr_in serveraddr;socklen_t addrlen = sizeof(serveraddr); serveraddr.sin_family = AF_INET; // 協議族 AF_INET:ipv4網絡協議// inet_addr: 將點分十進制字符串ip地址轉為整形數據serveraddr.sin_addr.s_addr = inet_addr(argv[1]); // ip地址// atoi 將數字型字符串轉換為整形數據// htons 將主機字節序轉化為網絡字節序serveraddr.sin_port = htons(atoi(argv[2]));// 將套接字和網絡信息綁定if(bind(sockfd,(struct sockaddr*)&serveraddr, addrlen) == -1){perror("fail to connect");exit(1);};// 將套接字設置為監聽狀態if(listen(sockfd,5) == -1){perror("fail to listen");exit(1);}struct sockaddr_in clientsock;addrlen = sizeof(clientsock);char buf[N] = "666";char text[N] = "";printf("準備阻塞...\n");// 阻塞等待客戶端的鏈接int clisock = accept(sockfd,(struct sockaddr*)&clientsock, &addrlen);int count = 0;while(1){ // 打印客戶端信息printf("ip:%s, port:%d\n", inet_ntoa(clientsock.sin_addr), ntohs(clientsock.sin_port));// 接收數據if((count = recv(clisock,text,N,0))==-1){perror("fail to recv");exit(1);}printf("from client: ");for(int j=0;j<count;j++){printf("%c",text[j]);}printf("\n");//發送buf數據if(send(clisock,buf,sizeof(buf),0)==-1){perror("fail to send");exit(1);}}// 關閉套接字描述符close(clisock);close(sockfd);return 0; }?
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多進程實現tcp并發服務器
#include<stdlib.h> #include<stdio.h> #include<string.h> #include<sys/types.h> #include<sys/socket.h> #include<arpa/inet.h> #include<netinet/in.h> #include<unistd.h> #include <signal.h> #include <sys/wait.h>#define N 128void handler(int sig){wait(NULL); }int main(int argc, char const * argv[]){if(argc < 3){fprintf(stderr, "server Usage:%s ip port\n",argv[0]);exit(1);}int sockfd;// 創建tcp套接字if((sockfd=socket(AF_INET,SOCK_STREAM,0)) == -1){perror("fail to socket");exit(1);}struct sockaddr_in serveraddr;socklen_t addrlen = sizeof(serveraddr); serveraddr.sin_family = AF_INET; // 協議族 AF_INET:ipv4網絡協議// inet_addr: 將點分十進制字符串ip地址轉為整形數據serveraddr.sin_addr.s_addr = inet_addr(argv[1]); // ip地址// atoi 將數字型字符串轉換為整形數據// htons 將主機字節序轉化為網絡字節序serveraddr.sin_port = htons(atoi(argv[2]));// 將套接字和網絡信息綁定if(bind(sockfd,(struct sockaddr*)&serveraddr, addrlen) == -1){perror("fail to connect");exit(1);};// 將套接字設置為監聽狀態if(listen(sockfd,5) == -1){perror("fail to listen");exit(1);}struct sockaddr_in clientsock;addrlen = sizeof(clientsock);char buf[N] = "666";char text[N] = "";printf("準備阻塞...\n");// 使用信號,異步的方式處理僵尸進程signal(SIGCHLD,handler);while(1){ // 阻塞等待客戶端的鏈接int clisock = accept(sockfd,(struct sockaddr*)&clientsock, &addrlen);int pid = fork();int count = 0;if(pid > 0){ // 父進程負責執行accept函數,所以if語句結束后,繼續在accept函數的位置阻塞}else if(pid == 0){ // 子進程負責跟指定的客戶端通信while(1){// 打印客戶端信息printf("ip:%s, port:%d\n", inet_ntoa(clientsock.sin_addr), ntohs(clientsock.sin_port));// 接收數據if((count = recv(clisock,text,N,0))==-1){perror("fail to recv");exit(1);}else if(count == 0){printf("The client quited\n");exit(0);}printf("from client: ");for(int j=0;j<count;j++){printf("%c",text[j]);}printf("\n");//發送buf數據if(send(clisock,buf,sizeof(buf),0)==-1){perror("fail to send");exit(1);}}}}// 關閉套接字描述符//close(clisock);//close(sockfd);return 0; }?
多線實現tcp并發服務器?
#include<stdlib.h> #include<stdio.h> #include<string.h> #include<sys/types.h> #include<sys/socket.h> #include<arpa/inet.h> #include<netinet/in.h> #include<unistd.h> #include <signal.h> #include <sys/wait.h> #include <pthread.h>#define N 128void handler(int sig){wait(NULL); }typedef struct{struct sockaddr_in addr;int acceptfd; }MSG;void *pthread_fun(void *arg){int count = 0;ssize_t bytes;MSG msg = *(MSG *)arg; char buf[N] = "666";char text[N] = "";while(1){// 打印客戶端信息printf("ip:%s, port:%d\n", inet_ntoa(msg.addr.sin_addr), ntohs(msg.addr.sin_port));// 接收數據if((count = recv(msg.acceptfd,text,N,0))==-1){perror("fail to recv");exit(1);}else if(count == 0){printf("The client quited\n");pthread_exit(NULL);}printf("from client: ");for(int j=0;j<count;j++){printf("%c",text[j]);}printf("\n");//發送buf數據if(send(msg.acceptfd,buf,sizeof(buf),0)==-1){perror("fail to send");exit(1);}} }int main(int argc, char const * argv[]){if(argc < 3){fprintf(stderr, "server Usage:%s ip port\n",argv[0]);exit(1);}int sockfd;// 創建tcp套接字if((sockfd=socket(AF_INET,SOCK_STREAM,0)) == -1){perror("fail to socket");exit(1);}struct sockaddr_in serveraddr;socklen_t addrlen = sizeof(serveraddr); serveraddr.sin_family = AF_INET; // 協議族 AF_INET:ipv4網絡協議// inet_addr: 將點分十進制字符串ip地址轉為整形數據serveraddr.sin_addr.s_addr = inet_addr(argv[1]); // ip地址// atoi 將數字型字符串轉換為整形數據// htons 將主機字節序轉化為網絡字節序serveraddr.sin_port = htons(atoi(argv[2]));// 將套接字和網絡信息綁定if(bind(sockfd,(struct sockaddr*)&serveraddr, addrlen) == -1){perror("fail to connect");exit(1);};// 將套接字設置為監聽狀態if(listen(sockfd,5) == -1){perror("fail to listen");exit(1);}struct sockaddr_in clientsock;addrlen = sizeof(clientsock);printf("準備阻塞...\n");// 使用信號,異步的方式處理僵尸進程signal(SIGCHLD,handler);while(1){ // 阻塞等待客戶端的鏈接int clisock = accept(sockfd,(struct sockaddr*)&clientsock, &addrlen);// 創建子線程與客戶端通信MSG msg;msg.addr = clientsock;msg.acceptfd = clisock;pthread_t thread;if(pthread_create(&thread,NULL,pthread_fun,&msg)!=0){perror("fail to pthread_create");}pthread_detach(thread);}// 關閉套接字描述符//close(clisock);//close(sockfd);return 0; }?
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