UDP实现聊天室

现象：

源码：

服务器：

#include<myhead.h>struct sockaddr_in serveraddr,caddr;
enum type_t//枚举
{Login,Chat,Quit,
};
typedef struct MSG
{char type;//L C Qchar name[32];//char text[128];//
}msg_t;typedef struct NODE//链表
{struct sockaddr_in caddr;struct NODE *next;
}node_t;node_t *create_node(void)//建头节点
{node_t *p=(node_t *)malloc(sizeof(node_t));if(p==NULL){perror("malloc err");return NULL;}p->next=NULL;return p;}
void do_login(int ,msg_t ,node_t *,struct sockaddr_in);//登录的函数
void do_chat(int ,msg_t ,node_t *,struct sockaddr_in);//群聊的函数
void do_quit(int ,msg_t ,node_t *,struct sockaddr_in);//退出函数
int main(int argc, char const *argv[])
{if(argc !=3){printf("Usage:./a.out <port>\n");return -1;}//创建UDP套接字int sockfd = socket(AF_INET,SOCK_DGRAM,0);if(sockfd<0){perror("socket err");exit(-1);}//填充服务器网络信息结构体serveraddr.sin_family=AF_INET;serveraddr.sin_port=htons(atoi(argv[2]));serveraddr.sin_addr.s_addr=inet_addr(argv[1]);socklen_t len = sizeof(caddr);//定义保存客户端网络信息的结构体//绑定套接字和服务器网络信息的结构体bind(sockfd,(struct sockaddr *)&serveraddr,sizeof(serveraddr));printf("bind ok!\n");msg_t msg;node_t *p=create_node();while(1){if(recvfrom(sockfd,&msg,sizeof(msg),0,(struct sockaddr *)&caddr,&len)<0){perror("recvfrom err");return -1;}if(msg.type==Login){strcpy(msg.text,"已上线");printf("ip:%s pord:%d name:%s\n",inet_ntoa(caddr.sin_addr),ntohs(caddr.sin_port),msg.name);printf("状态:%s\n",msg.text);do_login(sockfd,msg,p,caddr);}else if(msg.type==Chat){do_chat(sockfd,msg,p,caddr);    }else if(msg.type==Quit){strcpy(msg.text,"已下线");printf("ip:%s pord:%d name:%s\n",inet_ntoa(caddr.sin_addr),ntohs(caddr.sin_port),msg.name);printf("状态:%s\n",msg.text);do_quit(sockfd,msg,p,caddr);        }}close(sockfd);return 0;
}
//登录的函数
//功能：
//1》将新登录的用户转发给所有已经登录的用户（遍历链表发送谁登录的消息）
//2》创建新节点来保存新登录用户的信息，链接到链表尾就可已
void do_login(int sockfd,msg_t msg,node_t *p,struct sockaddr_in caddr)
{sprintf(msg.text,"%s 已上线",msg.name);while(p->next != NULL){p= p->next;sendto(sockfd,&msg,sizeof(msg),0,(struct sockaddr *)&(p->caddr),sizeof(p->caddr));//printf("%s\n",msg.text);}node_t *new=(node_t *)malloc(sizeof(node_t));//初始化new->caddr=caddr;new->next=NULL;//链接到链表尾p->next=new;return;
}
//群聊的函数
//功能：将客户端发来的聊天内容转发给所有已登录的用户，除了发送聊天内容的用户已外
void do_chat(int sockfd,msg_t msg,node_t *p,struct sockaddr_in caddr)
{//遍历链表while(p->next != NULL){p=p->next;if(memcmp(&(p->caddr),&caddr,sizeof(caddr)) != 0){sendto(sockfd,&msg,sizeof(msg),0,(struct sockaddr *)&(p->caddr),sizeof(p->caddr));}}return;
}
//退出函数
//功能：
//1》将谁退出的消息转发给i所有用户
//2》将链表中保存这个推出的用户信息的节点删除
void do_quit(int sockfd,msg_t msg,node_t *p,struct sockaddr_in caddr)
{sprintf(msg.text,"%s 已下线",msg.name);while(p->next != NULL){if((memcmp(&(p->next->caddr),&caddr,sizeof(caddr)))==0){ node_t *dele=NULL;dele = p->next;p->next=dele->next;free(dele);dele=NULL;}else{p=p->next;sendto(sockfd,&msg,sizeof(msg),0,(struct sockaddr *)&(p->caddr),sizeof(p->caddr));}  }return;
}

客户端：

#include <myhead.h>enum type_t
{Login,Chat,Quit,
};
typedef struct 
{char type;//L C Qchar name[32];//char text[128];//
}msg_t;int main(int argc, char const *argv[])
{if(argc !=3){printf("Usage ./a.out <ip> <port>\n");return -1;}int sockfd = socket(AF_INET,SOCK_DGRAM,0);if(sockfd<0){perror("socket err");exit(-1);}struct sockaddr_in serveraddr;serveraddr.sin_family=AF_INET;serveraddr.sin_port=htons(atoi(argv[2]));serveraddr.sin_addr.s_addr=inet_addr(argv[1]);socklen_t len = sizeof(serveraddr);msg_t msg;//先执行登录操作 printf("请登录:\n");msg.type=Login;printf("请输入用户名:");fgets(msg.name,32,stdin);if(msg.name[strlen(msg.name)-1]=='\n')msg.name[strlen(msg.name)-1]='\0';//发送登录消息if(sendto(sockfd,&msg,sizeof(msg),0,(struct sockaddr *)&serveraddr,len)<0){perror("sendto err");exit(-1);}pid_t pid=fork();if(pid<0){perror("fork err");exit(-1);}else if(pid==0){while(1){if(recvfrom(sockfd,&msg,sizeof(msg),0,NULL,NULL)<0){perror("recvfrom err");return -1;}printf("[%s]:%s\n",msg.name,msg.text);} }    else {while(1){fgets(msg.text,sizeof(msg.text),stdin);if(msg.text[strlen(msg.text)-1]=='\n')msg.text[strlen(msg.text)-1]='\0';if(strcmp(msg.text,"quit")==0){msg.type=Quit; sendto(sockfd,&msg,sizeof(msg),0,(struct sockaddr *)&serveraddr,len);kill(pid,SIGKILL);wait(NULL);exit(-1);}else{msg.type=Chat;}//发送消息sendto(sockfd,&msg,sizeof(msg),0,(struct sockaddr *)&serveraddr,len);}}close(sockfd);return 0;
}