C Bidirectional Client Server Example [duplicate] - c

Question

This question already has answers here:
Two-way communication in socket programming using C
(5 answers)
Closed 5 years ago.
I am fairly new to sockets and understand the point of a server client relationship. I was just wondering if there is some sort of way for the client to return a response to the server in c.
Im thinking, should I use the same socket connection, or create another file descriptor within my client to send it to my server. Also is there a better way to implement this?
The main goal is to have bidirectional communication.
I have provided my example code below:
Server:
void connection(char* sentMessage){
int listenfd = 0, connfd = 0;
struct sockaddr_in serv_addr;
char sendBuff[1025];
time_t ticks;
listenfd = socket(AF_INET, SOCK_STREAM, 0);
memset(&serv_addr, '0', sizeof(serv_addr));
memset(sendBuff, '0', sizeof(sendBuff));
serv_addr.sin_family = AF_INET;
serv_addr.sin_addr.s_addr = htonl(INADDR_ANY);
serv_addr.sin_port = htons(5000);
bind(listenfd, (struct sockaddr*)&serv_addr, sizeof(serv_addr));
listen(listenfd, 10);
while(1)
{
connfd = accept(listenfd, (struct sockaddr*)NULL, NULL);
ticks = time(NULL);
snprintf(sendBuff, sizeof(sendBuff), "%.90s\r\n", sentMessage);
write(connfd, sendBuff, strlen(sendBuff));
printf("Snoopy Detected: %s", sendBuff);
close(connfd);
sleep(1);
}
}
int main(int argc, char *argv[])
{
//construct a string to pass to the client
char* protocol = "eax:valuevlaue, ebx:asdjasdjasd, ecx:sadafw, edx:asdfsasd";
connection(protocol);
}
Client:
int main(int argc, char *argv[])
{
int sockfd = 0, n = 0;
char recvBuff[1024];
struct sockaddr_in serv_addr;
if(argc != 2)
{
printf("\n Usage: %s <ip of server> \n",argv[0]);
return 1;
}
memset(recvBuff, '0',sizeof(recvBuff));
if((sockfd = socket(AF_INET, SOCK_STREAM, 0)) < 0)
{
printf("\n Error : Could not create socket \n");
return 1;
}
memset(&serv_addr, '0', sizeof(serv_addr));
serv_addr.sin_family = AF_INET;
serv_addr.sin_port = htons(5000);
if(inet_pton(AF_INET, argv[1], &serv_addr.sin_addr)<=0)
{
printf("\n inet_pton error occured\n");
return 1;
}
if( connect(sockfd, (struct sockaddr *)&serv_addr, sizeof(serv_addr)) < 0)
{
printf("\n Error : Connect Failed \n");
return 1;
}
while ( (n = read(sockfd, recvBuff, sizeof(recvBuff)-1)) > 0)
{
recvBuff[n] = 0;
printf("Input: %s\n", recvBuff);
//parse it into eax, and such
char input[4][40];
char *ch;
int i = 0;
ch = strtok(recvBuff, ",");
while (ch != NULL) {
strcpy(input[i], ch);
ch = strtok(NULL, " ,");
i++;
}
//
// After this, do what you'd like with the input from donor
// And return the result back to the server
//
int j;
for(j = 0; j < 4 ; j++){
printf("%s\n", input[j]);
}
}
if(n < 0)
{
printf("\n Read error \n");
}
return 0;
}

Answer 1

Oh, I did it!
So apparently, sockets are inherently bidirectional, so all I had to do is write() back to the sockfd and read it from the server side!