security C

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CLIENT.c

#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <unistd.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <string.h>
#include<syslog.h>
#include<netdb.h>
#include<arpa/inet.h>
#define MAXLINE 4096

void err(char *s){
char *bufor;
sprintf(bufor," %s\n",s);
sprintf(bufor,"%d\n",errno);
sprintf(bufor,"%s\n",strerror(errno));
syslog(LOG_NOTICE|LOG_USER,bufor);
exit(-1);
}
 setlogmask(LOG_UPTO (LOG_NOTICE));
 openlog("exampleprog", LOG_CONS | LOG_PID | LOG_NDELAY, LOG_LOCAL1);
syslog(LOG_NOTICE,"Program started by User %d", stderr);
syslog(LOG_INFO, "A tree falls in a forest");
closelog();

struct hostent *hp;
if((hp = gethostbyname(argv[1]))==NULL);
{
syslog(LOG_ERR,"hostnameerror");
}
printf("Host: %s\n", hp->h_name);
char *ip = inet_ntoa(*((struct in_addr *)hp->h_addr));
printf("IP Address %s\n", inet_ntoa(*((struct in_addr *)hp->h_addr)));
if(inet_pton(AF_INET,ip,&servaddr.sin_addr)<0)
{
syslog(LOG_ERR,"Problem z formatem IP");
exit(1);
}
struct servent *sp;
sp = getservbyname(argv[2],"udp");
printf("Port: %d \n", sp->s_port);
if((servaddr.sin_port = htons(sp->s_port))<0)
{
syslog(LOG_ERR,"Zły format PORT");
exit(1);
}
int main(int argc, char **argv)
{
int sockfd,n;
char recvline[MAXLINE+1],buff[MAXLINE+1];
struct sockaddr_in servaddr;
if((sockfd = socket(AF_INET,SOCK_DGRAM,0))<0)
{
syslog(LOG_ERR,"Socket error");
exit(1);
}
bzero(&servaddr, sizeof(servaddr));
servaddr.sin_family = AF_INET;
struct hostent *hp;
if((hp = gethostbyname(argv[1]))==NULL);
{
syslog(LOG_ERR,"hostnameerror");
}
printf("Host: %s\n", hp->h_name);
char *ip = inet_ntoa(*((struct in_addr *)hp->h_addr));
printf("IP Address %s\n", inet_ntoa(*((struct in_addr *)hp->h_addr)));
if(inet_pton(AF_INET,ip,&servaddr.sin_addr)<0)
{
syslog(LOG_ERR,"Problem z formatem IP");
exit(1);
}
struct servent *sp;
sp = getservbyname(argv[2],"udp");
printf("Port: %d \n", sp->s_port);
if((servaddr.sin_port = htons(sp->s_port))<0)
{
syslog(LOG_ERR,"Zły format PORT");
exit(1);
}
while(1){
bzero(buff,sizeof(buff));
puts("Wyslij wiadomosc:");
if(fgets (buff, sizeof(buff), stdin) != NULL)
{
if(sendto(sockfd,buff,strlen(buff), 0, (struct sockaddr *)&servaddr,
sizeof(servaddr))<0)
{
syslog(LOG_ERR,"Blad sendto");
exit(1);
}
else
{
printf("Wysłano: %s\n",buff);
printf("Port poloczenia %d\n",servaddr.sin_port);
 printf("Port poloczenia %d \n",servaddr.sin_addr);
}
recvline[n]=0;
if((recvfrom(sockfd,recvline, MAXLINE, 0, NULL, NULL))<0)
{
syslog(LOG_ERR,"recvfrom error");
exit(1);
}
else
{
puts("****************");
printf("Otrzymałem: %s\n", recvline);
setlogmask(LOG_UPTO (LOG_NOTICE));
openlog("exampleprog", LOG_CONS | LOG_PID | LOG_NDELAY,
LOG_LOCAL1);
syslog(LOG_NOTICE,"Program started by User %d", stderr);
syslog(LOG_INFO, "A tree falls in a forest");
closelog();
printf("Port poloczenia %d\n",servaddr.sin_port);
printf("Port poloczenia %d \n",servaddr.sin_addr);
}
if(fputs(recvline, stdout) == EOF)
syslog(LOG_ERR,"Nie dziala fputs");
if(n < 0)
{
syslog(LOG_ERR,"Read error");
exit(1);
}
}
}
if(close(sockfd)<0)
{
syslog(LOG_ERR,"Close sockfd");
exit(1);
}
return 0;
}

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SERVER.c

#include <stdio.h>
#include<stdlib.h>
#include <errno.h>
#include<unistd.h>
#include <sys/types.h>
#include<sys/socket.h>
#include<netinet/in.h>
#include<string.h>
#include<syslog.h>
#include<netdb.h>
#define MAXLINE 4096
#define LISTENQ 1024

int main (int argc, char **argv)
{
int listenfd;
int len;
struct sockaddr_in servaddr, cliaddr;
char buff[MAXLINE],recvline[MAXLINE],z;
if(argc !=2)
{
syslog(LOG_ERR,"Serverport");
exit(1);
}
if((listenfd = socket (AF_INET, SOCK_DGRAM, 0 ))<0)
{
syslog(LOG_ERR,"Socket error");
exit(1);
}
int nn= 240*1024;
setsockopt(listenfd, SOL_SOCKET, SO_RCVBUF, &nn, sizeof(nn));
bzero(&servaddr, sizeof(servaddr));
puts("*");
struct servent *sp;
sp = getservbyname(argv[1],"udp");
printf("Port nr: %d\n", sp->s_port);
puts("**");
servaddr.sin_family = AF_INET;
servaddr.sin_addr.s_addr = htonl(INADDR_ANY);
if((servaddr.sin_port = htons(atoi(sp->s_port))<0))
{
syslog(LOG_ERR,"Zły port");
exit(1);
}
if(bind(listenfd, (struct sockaddr *) &servaddr, sizeof(servaddr))<0)
{
syslog(LOG_ERR,"Bind error");
exit(1);
}
while(1)
{
len = sizeof(cliaddr);
printf("listendf %d \n", listenfd);
if((recvfrom (listenfd, recvline, MAXLINE, 0 ,(struct sockaddr* )&cliaddr, &len))>0)
{
printf("Otrzymałem: %s \n",recvline);
printf("Port poloczenia %d\n",servaddr.sin_port);
 printf("Port poloczenia %d \n",servaddr.sin_addr);
 int i, j;
puts("***********************");
 for(i = strlen(recvline) - 1, j = 0; i >= 0; i--, j++) {
 buff[j] = recvline[i];
 }
 printf("Wysylam odpowiedz: %s\n", buff);
 sendto(listenfd, buff, sizeof(buff), 0, (struct sockaddr *)&cliaddr, len);
printf("Port poloczenia %d\n",servaddr.sin_port);
 printf("Port poloczenia %d \n",servaddr.sin_addr);
setlogmask(LOG_UPTO (LOG_NOTICE));
 openlog("exampleprog", LOG_CONS | LOG_PID | LOG_NDELAY, LOG_LOCAL1);
 syslog(LOG_NOTICE,"Program started by User %d", stderr);
 syslog(LOG_INFO, "End syslog");
 closelog();
}
}
if(close(listenfd) == -1)
{
syslog(LOG_ERR,"Bład zamkniecia");
exit(1);
}
return 0;
}