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tcp_communication.c
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tcp_communication.c
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#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <stdbool.h>
#include <errno.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>
#include <sys/wait.h>
#include "webserver.h"
/* via beej guide, and CSAPP */
int open_listenfd(char *port){
struct addrinfo hints, *listp, *p;
int listenfd, optval=1;
/* Get a list of potential server addresses */
memset(&hints, 0, sizeof(struct addrinfo));
hints.ai_socktype = SOCK_STREAM;
/* Accept connections */
hints.ai_flags = AI_PASSIVE | AI_ADDRCONFIG; /* ... on any IP address */
hints.ai_flags |= AI_NUMERICSERV;
/* ... using port number */
getaddrinfo(NULL, port, &hints, &listp);
/* Walk the list for one that we can bind to */
for (p = listp; p; p = p->ai_next) {
/* Create a socket descriptor */
if ((listenfd = socket(p->ai_family, p->ai_socktype, p->ai_protocol)) < 0)
continue; /* Socket failed, try the next */
/* Eliminates "Address already in use" error from bind */
setsockopt(listenfd, SOL_SOCKET, SO_REUSEADDR,
(const void *)&optval , sizeof(int));
/* Bind the descriptor to the address */
if (bind(listenfd, p->ai_addr, p->ai_addrlen) == 0)
break; /* Success */
close(listenfd); /* Bind failed, try the next */
}
/* Clean up */
freeaddrinfo(listp);
if (!p) /* No address worked */
return -1;
/* Make it a listening socket ready to accept connection requests */
if (listen(listenfd, BACKLOG) < 0) {
close(listenfd);
return -1;
}
return listenfd;
}
ssize_t read_tcp (int fd, int waittime, char *buffer){
struct timeval tv; tv.tv_sec = waittime; tv.tv_usec = 0;
size_t total_bytes_read = 0;
ssize_t bytes_read;
fd_set descriptors;
FD_ZERO(&descriptors);
FD_SET(fd, &descriptors);
while (total_bytes_read < BUFFER_SIZE) {
int ready = select(fd + 1, &descriptors, NULL, NULL, &tv);
if (ready < 0){
ERROR("select error");
}
if (ready == 0){
return 0;
}
bytes_read = recv(fd, buffer + total_bytes_read, BUFFER_SIZE - total_bytes_read, 0);
if (bytes_read < 0)
ERROR("recv error");
if (bytes_read == 0){
/* didnt read anything will close connection right aways*/
return 0;
}
total_bytes_read += bytes_read;
if (total_bytes_read > 3 && buffer[total_bytes_read-3] == 10 && buffer[total_bytes_read-2] == 13 && buffer[total_bytes_read-1] == 10){
buffer[total_bytes_read-2] = '\0';
break;
}
}
return 1;
}
/* write response to assoctiated fd*/
void respond(int fd, char *resp_buffer, int buff_size){
/*might need to handle if cant send all at once*/
buff_size = (buff_size == 0)? strlen(resp_buffer) : buff_size;
int bytes_sent = 0;
int size;
while(bytes_sent < buff_size){
size = (buff_size < MAXCHUNK )? buff_size : MAXCHUNK;
bytes_sent += send(fd, resp_buffer+bytes_sent, size, 0);
}
if(bytes_sent == -1)
perror("send error\n");
}