1. TCP和UDP通信模型
1.1 TCP server
#include <myhead.h>#define PORT 9999
#define IP "192.168.250.100"int main(int argc, const char *argv[])
{//1. create socketint sfd = -1;if( (sfd = socket(AF_INET, SOCK_STREAM, 0 ))==-1 ){perror("socket error");return -1;}//param1: AF_INET -->ipv4 domain //param2: AF_INET --> tcp protocal//param3; if param2 has specified only protocal, fill 0//returned: On success, a file descriptor for the new socket is returned. On error, -1 is returned, and errno is set appropriately.printf("sfd = %d\n", sfd); //2. bind address info structstruct sockaddr_in sin;sin.sin_family = AF_INET; //ipv4sin.sin_port = htons(PORT); // htons --> port in network bytes ordersin.sin_addr.s_addr = inet_addr(IP); //inet_addr--> address in network bytes orderif(bind(sfd, (struct sockaddr*)&sin, sizeof(sin)) == -1 ){perror("bind error");return -1;}//assigns the address specified by addr to the socket referred to by the file descriptor sockfd. //addrlen specifies the size, in bytes, of the address structure pointed to by addr. printf("bind success _%d_%s_%s\n", __LINE__, __FILE__, __func__); //3. listen() if( listen(sfd, 128) ==-1 ){perror("listen error");return -1;}//listen() marks the socket referred to by sockfd as a passive socket, //that is, as a socket that will be used to accept incoming connection requests using accept(2).printf("listen success _%d_%s_%s\n", __LINE__, __FILE__, __func__);//4. accept/*if(accept(sfd, NULL, NULL) == -1 ) // NULL, NULL means skip client info{perror("accept error");return -1;}printf("accept success _%d_%s_%s\n", __LINE__, __FILE__, __func__);*/// 4.1 accept, recv client info// define client info structstruct sockaddr_in cin;socklen_t socklen = sizeof(cin);//4.2 recv client requestsint newfd = -1;if( (newfd = accept(sfd, (struct sockaddr*)&cin, &socklen)) == -1 ){perror("accept error");return -1;}printf("[%s:%d] accept success, newfd = %d\n", inet_ntoa(cin.sin_addr), ntohs(cin.sin_port), newfd);//5. data send/recvchar rbuf[128] = "";while(1){//clean bufbzero(rbuf, sizeof(rbuf));int res = recv(newfd, rbuf, sizeof(rbuf), 0);//param1: file descriptor//param2: buff//param3: size//param4: blockif(res == 0){printf("client off line\n");break;}printf("[%s:%d] : %s\n", inet_ntoa(cin.sin_addr), ntohs(cin.sin_port), rbuf);//send back msg to clinetstrcpy(rbuf, "\n*_*\n");send(newfd, rbuf, sizeof(rbuf), 0);}close(newfd);close(sfd);return 0;
}
1.2 TCP client
#include <myhead.h>#define PORTSVC 9999
#define IPSVC "192.168.250.100"#define PORTCLI 6666
#define IPCLI "192.168.250.100"int main(int argc, const char *argv[])
{//1. create socketint cfd = -1;if( (cfd = socket(AF_INET, SOCK_STREAM, 0))==-1 ){perror("socket error");return -1;}printf("cfd = %d\n", cfd);//端口号快速重用int reuse = -1;if(setsockopt(cfd, SOL_SOCKET, SO_REUSEADDR, &reuse, sizeof(reuse)) == -1){perror("setsockopt error");return -1;}//2. bindingstruct sockaddr_in cin;cin.sin_family = AF_INET;cin.sin_port = htons(PORTCLI);cin.sin_addr.s_addr = inet_addr(IPCLI);if(bind(cfd, (struct sockaddr *)&cin, sizeof(cin)) == -1){perror("bind error");return -1;}printf("bind success\n");//3. connect serverstruct sockaddr_in sin;sin.sin_family = AF_INET;sin.sin_port = htons(PORTSVC);sin.sin_addr.s_addr = inet_addr(IPSVC);if( connect(cfd, (struct sockaddr *)&sin, sizeof(sin)) == -1){perror("connect error");return -1;}//4. data send/recvchar wbuf[128] = "";while(1){bzero(wbuf, sizeof(wbuf));//input textfgets(wbuf, sizeof(wbuf), stdin);wbuf[strlen(wbuf) - 1] = 0;if(strcmp(wbuf, "quit") == 0){printf("exit client\n");break;}//send data to svcsend(cfd, wbuf, sizeof(wbuf), 0);//data recvbzero(wbuf, sizeof(wbuf));int res = recv(cfd, wbuf, sizeof(wbuf), 0);if(res == 0){printf("server is off line\n");break;}printf("[%s:%d]: %s\n", IPSVC, PORTSVC, wbuf);}close(cfd);return 0;
}
2.1 upd server
#include <myhead.h>#define PORT 9999
#define IP "192.168.250.100"int main(int argc, const char *argv[])
{//1. create socketint sfd = -1;if( (sfd=socket(AF_INET, SOCK_DGRAM, 0 )) == -1 ){perror("socket error");return -1; }printf("sfd=%d\n", sfd);// port resueint reuse = 1;if( setsockopt(sfd, SOL_SOCKET, SO_REUSEADDR, &reuse, sizeof(reuse)) == -1 ){perror("setsockopt error");return -1;}//3. bind IPstruct sockaddr_in sin;sin.sin_family = AF_INET;sin.sin_port = htons(PORT);sin.sin_addr.s_addr = inet_addr(IP);if(bind(sfd, (struct sockaddr *)&sin, sizeof(sin)) == -1){perror("setsockopt error");return -1;}printf("bind success\n");//4. data recv/sendchar buf[128] = "";//addr struct struct sockaddr_in cin;socklen_t socklen = sizeof(cin);while(1){bzero(buf, sizeof(buf));recvfrom(sfd, buf, sizeof(buf), 0, (struct sockaddr*)&cin, &socklen);printf("[%s:%d]: %s\n", inet_ntoa(cin.sin_addr), ntohs(cin.sin_port), buf);//feedback to clinetstrcpy(buf, "*_*");sendto(sfd, buf, sizeof(buf), 0, (struct sockaddr *)&cin, sizeof(cin) );printf("send success\n");}close(sfd);return 0;
}
2.2 upd client
#include <myhead.h>#define PORT 9999
#define IP "192.168.250.100"int main(int argc, const char *argv[])
{//1. create socketint cfd =-1;if( (cfd = socket(AF_INET, SOCK_DGRAM, 0)) == -1 ){perror("socket error");return -1;}printf("cfd = %d\n", cfd);//2. binding ip, optional//3. define addr struct for data sendingstruct sockaddr_in sin;sin.sin_family = AF_INET;sin.sin_port = htons(PORT);sin.sin_addr.s_addr = inet_addr(IP);char buf[128] = "";//struct sockaddr_in cin;//socklen_t socklen = sizeof(cin);while(1){bzero(buf, sizeof(buf));// send data to serverfgets(buf, sizeof(buf), stdin);buf[strlen(buf) - 1] = 0;sendto(cfd, buf, sizeof(buf), 0, (struct sockaddr *)&sin, sizeof(sin));//recv data from serverrecvfrom(cfd, buf, sizeof(buf), 0, NULL, NULL );printf("msg from svc: %s\n", buf);}return 0;
}
2. 思维导图
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