C UDP server on background using thread - c

Question

Using thread, I wanted to launch UDP server on background.
But the server start and loop forever checking if any packet is received.
The same thread work fine if I use TCP server instead.
the test code is the following:
int udp_server_listen () {
printf("udp_server_listen \n");
int res;
unsigned char rsp_buf[1024];
struct sockaddr_in src;
socklen_t srclen;
memset(&src, 0, sizeof(src));
srclen = sizeof(src);
listen(s , 3);
//Accept and incoming connection
int c = sizeof(struct sockaddr_in);
int client_sock;
while( (client_sock = accept(s, (struct sockaddr *)&src, (socklen_t*)&c)) )
{
sleep(1);
printf("OK \n");
}
}
void *thread_udp_cr_listen (void *v)
{
udp_server_listen();
return NULL;
}
int s;
int main()
{
printf("start test \n");
struct sockaddr_in *local = malloc(sizeof (struct sockaddr_in *));
s = socket(AF_INET, SOCK_DGRAM, 0); // UDP
printf("create socket end\n");
int reusaddr = 1;
int reusport = 1;
if (setsockopt(s, SOL_SOCKET, SO_REUSEADDR, &reusaddr, sizeof(int)) < 0)
{
printf("setsockopt(SO_REUSEADDR) failed \n");
}
if (setsockopt(s, SOL_SOCKET, SO_REUSEPORT, &reusport, sizeof(int)) < 0)
{
printf("setsockopt(SO_REUSEPORT) failed \n");
}
struct timeval tv;
tv.tv_sec = 2; /* 30 Secs Timeout */
tv.tv_usec = 0; // Not init'ing this can cause strange errors
setsockopt(s, SOL_SOCKET, SO_RCVTIMEO, (char *)&tv,sizeof(struct timeval));
fcntl(s, F_SETFL, O_NONBLOCK);
printf(" Bind to a specific network interface and a specific local port\n");
int i = 0;
for(;i<6;i++)
{
if (bind(s, (struct sockaddr *)&local, sizeof(local)) < 0)
{
printf("bind Faild %d\n", i);
sleep(1);
continue;
}
break;
}
error = pthread_create(&udp_cr_server_thread, NULL, &thread_udp_cr_listen, NULL);
if (error<0)
{
printf("thread error \n");
}
pthread_join(udp_cr_server_thread, NULL);
}

Answer 1

You have one serious problem here:
struct sockaddr_in *local = malloc(sizeof (struct sockaddr_in *));
because you're just allocating the size of a pointer instead of the size of the struct itself.
This should of course be:
struct sockaddr_in *local = malloc(sizeof (struct sockaddr_in));
Two more problems with the same variable in this line:
if (bind(s, (struct sockaddr *)&local, sizeof(local)) < 0)
This should be:
if (bind(s, (struct sockaddr *)local, sizeof(*local)) < 0)