how can i display client address using c socket program? - c

Question

My project is : Client receives the raw packet from the Ethernet saves it in a file called 'sniff_data.bin' and sends it to the server. Server receives the contents processes the packet( distinguishes between tcp,icmp,udp etc) and saves in a text file called 'info_agent_ report. txt' file. i think there is some mistake in my code. can anybody please guide me , help me out.
int main()
{
int sockfd, new_sockfd,log,n,x1,x2;
int server_len, client_len,len;
int cont,fh,cont2,x;
int result1;
struct sockaddr_in serveraddress;
struct sockaddr_in address;
struct sockaddr_in client_address;
FILE *ia_address;
char *fname = "/home/shishira/Desktop/packet_capture/info_agent_report.txt";
int buffsize=1024;
char buffer1[1024];
char buffer[1024];
char clntName[INET_ADDRSTRLEN];
if((sockfd = socket(AF_INET,SOCK_STREAM,0))>0)
printf("\n ---------------------------Task Agent---------------------------\n");
printf("\n Socket was created\n");
/* Name the socket. */
address.sin_family = AF_INET;
address.sin_addr.s_addr = inet_addr("127.0.0.1");
address.sin_port = htons(9734);
server_len = sizeof(address);
bind(sockfd, (struct sockaddr *)&address, server_len);
/* Create a connection queue and wait INFO_AGENT_REPORTS */
listen(sockfd, 5);
while(1)
{
char ch;
printf("\n\n Task agent waiting...\n");
/* Accept a connection to collect report from INFO_AGENT */
client_len = sizeof(client_address);
new_sockfd = accept(sockfd,(struct sockaddr *)&client_address, &client_len);
if (new_sockfd==-1) { perror("Connection Not Accepted!!"); return(1);}
else
{
// x=fork();
// if (x==0) // child process starts
// {
printf("\n Information agent is connected\n");
//for displaying the client address
if(inet_ntop(AF_INET,&client_address.sin_addr.s_addr,clntName,sizeof(clntName))!=NULL)
{
ia_address = fopen("info_agent_report.txt","a+");
fprintf(ia_address,"\nFrom InformationAgent:%s\n",clntName);
fclose(ia_address);
}
printf("\n Task agent processed the contents and saved it in 'info_agent_report'
file\n\n");
log=open("info_agent_report.txt",O_CREAT|O_RDWR|O_APPEND,0777);
if(log==-1)
{
perror("cannot open info_agent_report file\n");
return(1);
}
do
{
x1=read(new_sockfd, buffer1, 1024);
x2=write(log,buffer1,x1);
}
while (x1>0);
data_process();//for processing the packet
close(log);
// } child process ends
close(new_sockfd);
}
}
I have written the code for displaying the client address in info_agent_report.txt. but is not getting dispalyed :(

Answer 1

To display client name: ( put this after accept )
char clntName[INET_ADDRSTRLEN]; // String to contain client address
if (inet_ntop(AF_INET, &clntAddr.sin_addr.s_addr, clntName,sizeof(clntName)) != NULL){
printf("Handling client %s/%d\n", clntName, ntohs(clntAddr.sin_port));
}
Or this:
char clntName[INET6_ADDRSTRLEN];
char portName[6];
if(getnameinfo(&client_address,sizeof client_address,clntName,sizeof(clntName),NULL,0,NI_NUMERICHOST|NI_NUMERICSERV|NI_NUMERICSCOPE)==0){
printf("Client = %s/%s\n",clntName,portName);
} else {
printf("Unable to get address\n");
}