Simple C udp client/server fails - c

Question

I am trying to write a server program that just displays any raw data it receives from anyone through udp. A client can send some data to it at any time. No errors appear except for "Socket error: Resource temporarily unavailable" which in other words mean that recvfrom has no data to receive (because it's presumably not getting any packets).
The client just sends "test!" to 127.0.0.0:12345, while the server listens with a non-blocking socket on port 12345. It may be worth noting that I am on linux.
Why is server not displaying the packets that it's obviously being sent from client? I don't see what I'm missing.
common.h
#include <stdlib.h>
#include <stdint.h>
#include <stdio.h>
#include <errno.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <fcntl.h>
typedef struct sockaddr_in sockaddr_in;
typedef struct sockaddr sockaddr;
int createSocket(uint16_t port)
{
int handle = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
if (handle <= 0)
{
printf("failed to create socket\n");
return 0;
}
sockaddr_in address;
address.sin_family = AF_INET;
address.sin_addr.s_addr = INADDR_ANY;
address.sin_port = htons(port);
if (bind(handle, (const sockaddr*)&address, sizeof(sockaddr_in)) < 0)
{
printf("failed to bind socket\n");
return 0;
}
int nonBlocking = 1;
if (fcntl(handle, F_SETFL, O_NONBLOCK, nonBlocking) == -1)
{
printf("failed to set non-blocking\n");
return 0;
}
return handle;
}
int sendData(uint32_t a, uint32_t b, uint32_t c, uint32_t d, uint16_t port, int handle, char* packet_data, int packet_size)
{
uint32_t address = (a << 24) | (b << 16) | (c << 8) | d;
sockaddr_in addr;
addr.sin_family = AF_INET;
addr.sin_addr.s_addr = htonl(address);
addr.sin_port = htons(port);
int sent_bytes = sendto(handle, (const char*)packet_data, packet_size, 0, (sockaddr*)&address, sizeof(sockaddr_in));
if (sent_bytes != packet_size)
{
printf("failed to send packet (%d/%d)\n", sent_bytes, packet_size);
return 0;
}
}
server.c
#include "common.h"
#include <time.h>
void main(void){
int socket = createSocket(12345);
if (!socket){
perror("Socket error");
}
int true=1;
setsockopt(socket, SOL_SOCKET, SO_REUSEADDR, (const void*)&true, 1);
// so that we can immediately reuse the port if the server stops running
char buffer[100] = "No data";
if(!listen(socket, 0)){
perror("Socket error");
}
//struct timespec delay = {0,33333333}; // 30Hz
struct timespec delay = {0,100000000}; // 100Hz
int running = 1;
int ret = 0;
while(running){
ret = recvfrom(socket, &buffer, 100, 0, NULL, NULL);
if (ret < 0){
perror("Socket error");
} else if (ret > 0){
printf("%d: %s\n", ret, buffer);
}
nanosleep(&delay,NULL);
}
}
client.c
#include "common.h"
void main(void){
int socket = createSocket(0);
printf("Started client on port %d\n", socket);
if(!sendData(127,0,0,0,12345, socket, "test!", 5)){
perror("Socket error");
} else {
printf("Sent data.\n");
}
}

Answer 1

I passed a pointer to address where I was supposed to pass a pointer to addr in common.h -> sendTo().
On top of that, I was sending packets to 127.0.0.0 when that should have been 127.0.0.1 (thanks #yano).
Corrected code:
int sendData(uint32_t a, uint32_t b, uint32_t c, uint32_t d, uint16_t port, int handle, char* packet_data, int packet_size)
{
uint32_t address = (a << 24) | (b << 16) | (c << 8) | d;
sockaddr_in addr;
addr.sin_family = AF_INET;
addr.sin_addr.s_addr = htonl(address);
addr.sin_port = htons(port);
int sent_bytes = sendto(handle, (const char*)packet_data, packet_size, 0, (sockaddr*)&addr, sizeof(sockaddr_in));
if (sent_bytes != packet_size)
{
printf("failed to send packet (%d/%d)\n", sent_bytes, packet_size);
return 0;
}
}