UDP와TCP 소켓을 모두 사용하는 서버(select를 poll로 바꿔보기,중요)

#include <stdio.h>
#include <errno.h>
#include <stdlib.h>
#include <arpa/inet.h>
#include <signal.h>
#include <sys/socket.h>
#include <string.h>
#include <netinet/in.h>
#include <unistd.h>
#define MAXLINE 4096
#define SA struct sockaddr
#define max(X,Y) ((X) > (Y) ? (X) : (Y))
#define LISTENQ 5
void str_echo(int sockfd)
{
ssize_t n;
char buf[MAXLINE];
again:
    while ( (n = read(sockfd, buf, MAXLINE)) > 0)
        write(sockfd, buf, n);
    if (n < 0 && errno == EINTR)
        goto again;
    else if (n < 0)
        perror("str_echo: read error");
}
 
void sig_chld(){return;}
 
int main(int argc, char **argv)
{
    int listenfd,connfd,udpfd,nready,maxfdp1;
    char mesg[MAXLINE];
    pid_t childpid;
    fd_set rset;
    ssize_t n;
    socklen_t len;
    const int on = 1;
    struct sockaddr_in cliaddr, servaddr;
    void sig_child(int);
 
    /*create listening TCP socket*/
    listenfd = socket(AF_INET,SOCK_STREAM,0);
    bzero(&servaddr,sizeof(servaddr));
    servaddr.sin_family = AF_INET;
    servaddr.sin_addr.s_addr = htonl(INADDR_ANY);
    servaddr.sin_port = htons(30018);
 
    setsockopt(listenfd , SOL_SOCKET, SO_REUSEADDR, &on,sizeof(on));
    bind(listenfd,(SA*)&servaddr,sizeof(servaddr));
 
    listen(listenfd,LISTENQ);
 
    /*create UDP socket */
    udpfd = socket(AF_INET,SOCK_DGRAM,0);
    bzero(&servaddr,sizeof(servaddr));
    servaddr.sin_family = AF_INET;
    servaddr.sin_addr.s_addr = htonl(INADDR_ANY);
    servaddr.sin_port = htons(30018);
    
    bind(udpfd,(SA*)&servaddr,sizeof(servaddr));
 
    signal(SIGCHLD, sig_chld); /* must call waitpid() */
 
    FD_ZERO(&rset);
    maxfdp1 = max(listenfd,udpfd) + 1;
    for(; ; ) {
        FD_SET(listenfd,&rset);
        FD_SET(udpfd,&rset);
        if( (nready = select(maxfdp1, &rset, NULL,NULL,NULL))<0){
            if(errno == EINTR)
                continue;
            else
                perror("select error");
        }
        if(FD_ISSET(listenfd,&rset)){
            len = sizeof(cliaddr);
            connfd = accept(listenfd,(SA*)&cliaddr,&len);
 
            if( (childpid = fork() ) == 0){
                close(listenfd);
        str_echo(connfd);
        exit(0);
        }
        close(connfd);
    }
    if(FD_ISSET(udpfd,&rset)){  
        len = sizeof(cliaddr);
                n = recvfrom(udpfd, mesg, MAXLINE, 0, (SA*) &cliaddr, &len);
                sendto(udpfd,mesg,n,0,(SA *)&cliaddr,len);
        }
    }
}
 
 

tcp클라이언트 프로그램

#include <stdio.h>
#include <errno.h>
#include <stdlib.h>
#include <arpa/inet.h>
#include <signal.h>
#include <sys/socket.h>
#include <string.h> 
#include <netinet/in.h>
#include <unistd.h>
#define SA struct sockaddr
#define MAXLINE 4096
 
void str_cli(FILE *fp, int sockfd)
{
    char sendline[MAXLINE], recvline[MAXLINE];
    while(fgets(sendline, MAXLINE, fp) != NULL) {
        write(sockfd, sendline, strlen(sendline));
    if (read(sockfd, recvline, MAXLINE) == 0)
        perror("str_cli: server terminated prematurely");
    fputs(recvline, stdout);
    }
}
int main(int argc, char **argv)
{
    int sockfd;
    struct sockaddr_in servaddr;
    if (argc != 2)
        perror("usage: tcpcli <IPaddress>");
    sockfd = socket(AF_INET, SOCK_STREAM, 0);
    bzero(&servaddr, sizeof(servaddr));
    servaddr.sin_family = AF_INET;
    servaddr.sin_port = htons(30018);
    inet_pton(AF_INET, argv[1], &servaddr.sin_addr);
    connect(sockfd, (SA *) &servaddr, sizeof(servaddr));
    str_cli(stdin, sockfd);
    return 0;
}
 

udp 클라이언트 프로그램

#include <stdio.h>
#include <errno.h>
#include <stdlib.h>
#include <arpa/inet.h>
#include <signal.h>
#include <sys/socket.h>
#include <string.h>
#include <netinet/in.h>
#include <unistd.h>
#define SA struct sockaddr
#define MAXLINE 4096
 
void dg_cli(FILE *fp, int sockfd, const SA *pservaddr, socklen_t servlen)
{
    int n;
    char sendline[MAXLINE], recvline[MAXLINE + 1];
    while (fgets(sendline, MAXLINE, fp) != NULL) {
        sendto(sockfd, sendline, strlen(sendline), 0, pservaddr, servlen);
        n = recvfrom(sockfd, recvline, MAXLINE, 0, NULL, NULL);
        recvline[n] = 0; /* null terminate */
        fputs(recvline, stdout);
    }
}
int main(int argc, char **argv)
{
    int sockfd;
    struct sockaddr_in servaddr;
    if(argc != 2)
        perror("usage: udpcli <IPaddress>");
    bzero(&servaddr, sizeof(servaddr));
    servaddr.sin_family = AF_INET;
    servaddr.sin_port = htons(30018);
    inet_pton(AF_INET, argv[1], &servaddr.sin_addr);
    sockfd = socket(AF_INET, SOCK_DGRAM, 0);
    dg_cli(stdin, sockfd, (SA *) &servaddr, sizeof(servaddr));
    exit(0);
}
 

tcp 패킷과 udp패킷 모두 잘 처리하는 모습