服务器端代码如果采用fork写时复制(Copy on Write)技术,代码还可以更简洁一点
服务端代码:
- #include <stdio.h>
- #include <stdlib.h>
- #include <sys/socket.h>
- #include <unistd.h>
- #include <string.h>
- #include <errno.h>
- #include <netdb.h>
- #include <arpa/inet.h>
- #define BUFSIZE 4096
- #define CHILD_PORT_START 16500
-
- const char* Inet_ntop(void* ptr) {
- static char str[INET_ADDRSTRLEN];
- return inet_ntop(AF_INET,ptr,str,INET_ADDRSTRLEN);
- }
-
- void server_echo(int sockfd) {
- int fullfd[2];
- if (socketpair(AF_UNIX,SOCK_DGRAM,0,fullfd) < 0) {
- printf("sockpair error: %s\n",strerror(errno));
- exit(1);
- }
- char recv[BUFSIZE];
- struct sockaddr_in clientaddr;
- socklen_t len = sizeof(struct sockaddr_in);
- ssize_t n;
- struct iovec iov[2];
- int pid;
- for (; ;) {
- if ((n = recvfrom(sockfd,recv,BUFSIZE,(struct sockaddr*)&clientaddr,&len)) < 0) {
- printf("receive from client error: %s\n",strerror(errno));
- break;
- }
- iov[0].iov_base = &clientaddr;
- iov[0].iov_len = len;
- iov[1].iov_base = recv;
- iov[1].iov_len = n;
- if (writev(fullfd[0],iov,2) != n + len) {
- printf("writev to child error: %s\n",strerror(errno));
- exit(1);
- }
- if ((pid = fork()) < 0) {
- printf("fork error: %s\n",strerror(errno));
- break;
- }else if (pid == 0) {
- struct sockaddr_in to;
- socklen_t tolen = sizeof(struct sockaddr_in);
- int childfd;
- struct sockaddr_in server;
- server.sin_family = AF_INET;
- server.sin_port = getpid() - getppid() + CHILD_PORT_START;
- server.sin_addr.s_addr = htonl(INADDR_ANY);
- struct iovec get[2];
- char send[BUFSIZE];
- ssize_t count = n;
- get[0].iov_base = &to;
- get[0].iov_len = sizeof(struct sockaddr_in);
- get[1].iov_base = send;
- get[1].iov_len = BUFSIZE;
- if (readv(fullfd[1],get,2) != count + tolen) {
- printf("readv error: %s\n",strerror(errno));
- exit(1);
- }
- printf("child process pid = %d handle from IP: %s client\n",getpid(),Inet_ntop(&to.sin_addr));
- if ((childfd = socket(AF_INET,IPPROTO_UDP)) < 0) {
- printf("child socket error: %s\n",strerror(errno));
- }
- if (bind(childfd,(struct sockaddr*)&server,sizeof(struct sockaddr_in)) < 0) {
- printf("child bind error: %s\n",strerror(errno));
- exit(1);
- }
- if (sendto(childfd,send,count,(struct sockaddr*)&to,tolen) != count) {
- printf("send to error: %s\n",strerror(errno));
- exit(1);
- }
- while ((count = recvfrom(childfd,&tolen)) > 0) {
- if (sendto(childfd,tolen) != count) {
- printf("send to client error: %s\n",strerror(errno));
- exit(1);
- }
- }
- }
- }
- }
- int main(int argc,char** argv) {
- if (argc != 2) {
- printf("please add or check <service name>\n");
- exit(1);
- }
-
- struct addrinfo hints;
- bzero(&hints,sizeof(struct addrinfo));
- hints.ai_flags = AI_PASSIVE;
- hints.ai_family = AF_INET;
- hints.ai_socktype = SOCK_DGRAM;
- hints.ai_protocol = IPPROTO_UDP;
-
- struct addrinfo* results;
- int err;
- if ((err = getaddrinfo(NULL,argv[1],&hints,&results)) != 0) {
- printf("getaddrinfo error: %s\n",gai_strerror(err));
- exit(1);
- }
- struct addrinfo* dummy = results;
- int sockfd;
- for (; dummy != NULL; dummy = dummy->ai_next) {
- if ((sockfd = socket(dummy->ai_family,dummy->ai_socktype,dummy->ai_protocol)) < 0) {
- continue;
- }
- if (ntohs(((struct sockaddr_in*)dummy->ai_addr)->sin_port) >= CHILD_PORT_START) {
- printf("Warnning:Dangerous use the port,if have many client,so you should use less than the port try once again\n");
- close(sockfd);
- exit(1);
- }
- if (bind(sockfd,dummy->ai_addr,dummy->ai_addrlen) == 0) {
- break;
- }
- close(sockfd);
- }
- server_echo(sockfd);
- return 0;
- }
客户端代码:
- #include <stdio.h>
- #include <stdlib.h>
- #include <sys/socket.h>
- #include <unistd.h>
- #include <string.h>
- #include <errno.h>
- #include <netdb.h>
-
- #define BUFSIZE 4096
-
- void client_echo(int sockfd,struct sockaddr* to,socklen_t tolen) {
- char send[BUFSIZE];
- ssize_t n;
- struct sockaddr_in clientaddr;
- const int on = 1;
- socklen_t len = sizeof(struct sockaddr_in);
- if (setsockopt(sockfd,SOL_SOCKET,SO_BROADCAST,&on,sizeof(on)) < 0) {
- printf("setsockopt error: %s\n",strerror(errno));
- exit(1);
- }
- while ((n = read(STDIN_FILENO,BUFSIZE)) > 0) {
- if (sendto(sockfd,n,to,tolen) != n) {
- printf("sendto error: %s\n",strerror(errno));
- exit(1);
- }
- if (recvfrom(sockfd,&len) != n) {
- printf("recv from server error: %s\n",strerror(errno));
- exit(1);
- }
- struct sockaddr_in *dummy = (struct sockaddr_in*)to;
- dummy->sin_port = clientaddr.sin_port;
- if (write(STDOUT_FILENO,n) != n) {
- printf("write error: %s\n",strerror(errno));
- exit(1);
- }
- }
- }
- int main(int argc,char** argv) {
- if (argc != 3) {
- printf("please add <ip address-host name> <service name or port name>\n");
- exit(1);
- }
-
- struct addrinfo hints;
- bzero(&hints,sizeof(struct addrinfo));
- hints.ai_flags = AI_ALL;
- hints.ai_family = AF_INET;
- hints.ai_socktype = SOCK_DGRAM;
- hints.ai_protocol = IPPROTO_UDP;
-
- struct addrinfo* results;
- int err;
- if ((err = getaddrinfo(argv[1],argv[2],gai_strerror(err));
- exit(1);
- }
-
- struct addrinfo* dummy = results;
- int sockfd;
- for (; dummy != NULL; dummy = dummy->ai_next) {
- if ((sockfd = socket(dummy->ai_family,dummy->ai_protocol)) < 0) {
- continue;
- }else {
- break;
- }
- }
-
- if (dummy == NULL) {
- freeaddrinfo(results);
- printf("all socket Failed\n");
- exit(1);
- }
- client_echo(sockfd,dummy->ai_addrlen);
- freeaddrinfo(results);
- }