TCPusingUDP/lib_tcp.c at master · vineeth-thumma/TCPusingUDP · GitHub

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#include <string.h>
#include <stdio.h>
//Socket related header files
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>
#include <stdlib.h>
#include <strings.h>
#include <unistd.h>


ssize_t SEND(int sockfd, const void *buf, size_t len, int flags) {

struct sockaddr_in sin_addr;
struct hostent *hp;
int ret;
hp = gethostbyname("127.0.0.1");
bcopy((void *)hp->h_addr, (void *)&sin_addr.sin_addr, hp->h_length);
sin_addr.sin_family = AF_INET;
sin_addr.sin_port = htons(atoi("10809"));    /* fixed by adding htons() */
memset(sin_addr.sin_zero, '\0', sizeof(sin_addr.sin_zero));

char *send_buf = NULL;
send_buf = malloc(sizeof(unsigned char) * (len+1));     //allocating buffer of size 1000 bytes to send 2+bytes requested
memset(send_buf, '\0', (len+1));
send_buf[0] = '1';
memcpy(send_buf+1, buf, len);

ret = (sendto(sockfd,send_buf,len+1,flags,(struct sockaddr *) &sin_addr, sizeof(struct sockaddr_in)));
free(send_buf);
char ackbuf[4];
memset(ackbuf, 0, sizeof ackbuf);
recvfrom(sockfd, ackbuf, sizeof ackbuf, flags, (struct sockaddr*)NULL, NULL);
while(strcmp(ackbuf, "ack") != 0){
recvfrom(sockfd, ackbuf, sizeof ackbuf, flags, (struct sockaddr*)NULL, NULL);
}
return ret;
}


ssize_t RECV(int sockfd, void *buf, size_t len, int flags) {

    struct sockaddr_in name;
    struct hostent *hp;
    int ret;
    hp = gethostbyname("127.0.0.1");
    bcopy((void *)hp->h_addr, (void *)&name.sin_addr, hp->h_length);
    name.sin_family = AF_INET;
    name.sin_port = htons(atoi("10809"));
    memset(name.sin_zero, '\0', sizeof(name.sin_zero));
 int addr_len = sizeof(struct sockaddr_in);

char *send_buf = NULL;
int size_req = len;
size_req = htonl(size_req);
int headersize = 5;

send_buf = malloc(sizeof(unsigned char) * (5));     //allocating buffer of size 1000 bytes to send 2+bytes requested
memset(send_buf, '\0', headersize);
send_buf[0] = '2';
memcpy(send_buf+1, &size_req, 4);

sendto(sockfd,send_buf, 5, flags,(struct sockaddr *) &name, sizeof(struct sockaddr_in));
int receivedbytes = recvfrom(sockfd, buf, len, flags, (struct sockaddr *)NULL, NULL);
free(send_buf);

return receivedbytes;

}


int BIND(int sockfd, const struct sockaddr *addr, socklen_t addrlen) {

return (bind(sockfd, addr, addrlen));

}

int SOCKET(int domain, int type, int protocol) {

return (socket(domain, SOCK_DGRAM, protocol));

}

int CONNECT(int sockfd, const struct sockaddr *addr, socklen_t addrlen) {

 return 0;

}

int ACCEPT(int sockfd, struct sockaddr *addr, socklen_t *addrlen) {

 return sockfd;

}

int LISTEN(int sockfd, int backlog) {

 return 0;

}