linux下TCP/IP实现简单聊天程序
可以在同一台电脑上运行，在一个终端上运行服务器端，在一个终端上运行客户端。
服务器端的IP地址要和本地的IP相同，并分配端口号，客户端的默认设置为本地，端口号自动分配。
服务器端：
#include <stdio.h> #include <stdlib.h> #include <errno.h> #include <string.h> #include <sys/types.h> #include <netinet/in.h> #include <sys/socket.h> #include <sys/wait.h> #include <unistd.h> #include <arpa/inet.h> #define MAXBUF 1024 int main(int argc, char *argv[]) { int pid; int sockfd, new_fd; socklen_t len; struct sockaddr_in my_addr, their_addr; unsigned int myport, lisnum; char buf[MAXBUF + 1]; if (argv[2]) myport = atoi(argv[2]); else myport = 7575; if (argv[3]) lisnum = atoi(argv[3]); else lisnum = 5; if ((sockfd = socket(AF_INET, SOCK_STREAM, 0)) == -1) { perror("socket"); exit(EXIT_FAILURE); } bzero(&my_addr, sizeof(my_addr)); my_addr.sin_family = AF_INET; my_addr.sin_port = htons(myport); if (argv[1]) my_addr.sin_addr.s_addr = inet_addr(argv[1]); else my_addr.sin_addr.s_addr = INADDR_ANY; if (bind(sockfd, (struct sockaddr *) &my_addr, sizeof(struct sockaddr))== -1) { perror("bind"); exit(EXIT_FAILURE); } if (listen(sockfd,lisnum ) == -1) { perror("listen"); exit(EXIT_FAILURE); } printf("wait for connect\n"); len = sizeof(struct sockaddr); if ((new_fd =accept(sockfd, (struct sockaddr *) &their_addr,&len)) == -1) { perror("accept"); exit(EXIT_FAILURE); } else printf("server: got connection from %s, port %d, socket %d\n",inet_ntoa(their_addr.sin_addr),ntohs(their_addr.sin_port), new_fd); if(-1==(pid=fork())) { perror("fork");exit(EXIT_FAILURE); } else if( pid == 0) { while (1) { bzero(buf, MAXBUF + 1); printf("input the message to send:"); fgets(buf, MAXBUF, stdin); if (!strncasecmp(buf, "quit", 4)) { printf("i will close the connect!\n"); break; } len = send(new_fd, buf, strlen(buf) - 1, 0); if (len < 0) { printf("message'%s' send failure!errno code is %d,errno message is '%s'\n", buf, errno, strerror(errno)); break; } } } else { while(1) { bzero(buf, MAXBUF + 1); len = recv(new_fd, buf, MAXBUF, 0); if (len > 0) printf("message recv successful :'%s',%dByte recv\n",buf, len); else if (len < 0) { printf("recv failure!errno code is %d,errno message is '%s'\n", errno, strerror(errno)); break; } else { printf("the other one close quit\n"); break; } } } close(new_fd); close(sockfd); return 0; } 客户端：
#include <stdio.h> #include <string.h> #include <errno.h> #include <sys/socket.h> #include <resolv.h> #include <stdlib.h> #include <netinet/in.h> #include <arpa/inet.h> #include <unistd.h> #define MAXBUF 1024 int main(int argc, char **argv) { int sockfd, len; struct sockaddr_in dest; char buffer[MAXBUF + 1]; if (argc != 3) { printf(" error format,it must be:\n\t\t%s IP port\n",argv[0]); exit(EXIT_FAILURE); } if ((sockfd = socket(AF_INET, SOCK_STREAM, 0)) < 0) { perror("Socket"); exit(errno); } printf("socket created\n"); bzero(&dest, sizeof(dest)); dest.sin_family = AF_INET; dest.sin_port = htons(atoi(argv[2])); if (inet_aton(argv[1], (struct in_addr *) &dest.sin_addr.s_addr) == 0) { perror(argv[1]); exit(errno); } if (connect(sockfd, (struct sockaddr *) &dest, sizeof(dest))==-1) { perror("Connect "); exit(errno); } printf("server connected\n"); pid_t pid; if(-1==(pid=fork())) { perror("fork");exit(EXIT_FAILURE); } else if (pid==0) { while (1) { bzero(buffer, MAXBUF + 1); len = recv(sockfd, buffer, MAXBUF, 0); if (len > 0) printf("recv successful:'%s',%d byte recv\n",buffer, len); else if(len < 0) { perror("recv"); break; } else { printf("the other one close ,quit\n"); break; } } } else { while (1) { bzero(buffer, MAXBUF + 1); printf("pls send message to send:"); fgets(buffer, MAXBUF, stdin); if (!strncasecmp(buffer, "quit", 4)) { printf(" i will quit!\n"); break; } len = send(sockfd, buffer, strlen(buffer) - 1, 0); if (len < 0) { perror("send"); break; } } } close(sockfd); return 0; }
服务器端执行 ： ./s 192.168.142.132 7575 5
客户端执行： ./c 192.168.142.132 7575
其中，192.168.142.132是本机的IP地址.
服务器端信息：
root@jieniyimiao-virtual-machine:/home/jieniyimiao/c_code/linux/ch13/sock_tcp_p_p_chat# ./s 192.168.142.132 7575 5
wait for connect
server: got connection from 192.168.142.132, port 44698, socket 4
input the message to send:jieniyimiap
input the message to send:ddddddddddddddddddddddddddd
input the message to send:dddddddddddddddddddddddddddd
input the message to send:aaaaaaaaaaaaaaaaaaaaaa
input the message to send:aaaaaaaaaaaaaaaaaaaaaaaa
input the message to send:message recv successful :'dddddddddddddddddd',18Byte recv
message recv successful :'ddddddddddddddddd',17Byte recv
message recv successful :'ddddddddddddddddd',17Byte recv
message recv successful :'dddddddddddddd',14Byte recv
message recv successful :'ddddddddddddddd',15Byte recv
message recv successful :'ddddddddddddddddd',17Byte recv
message recv successful :'dddddddddddddd',14Byte recv
quit
i will close the connect!
客户端略：
用NETSTAT查看信息如下：
# netstat |grep 192.168.142.132
**********************************************************************************
tcp 0 0 192.168.142.132:7575 192.168.142.132:44698 ****
tcp 0 0 192.168.142.132:44698 192.168.142.132:7575 ****