bind() fails with windows socket error 10049 - c

Question

I try to make a client/server program in C with IPv6 and UDP. When the program binds the socket it return the WSAError 10049. I know that this is a problem with the adress name but don't see whats the problem. I hope someone can help.
struct sockaddr_in6 server, client;
SOCKET sock;
char buffer[BUFFERSIZE];
LPTSTR recvBuff[1024];
DWORD recvBuffLen = 1024UL;
int len = sizeof(client);
WORD wVersionRequested;
WSADATA wsaData;
wVersionRequested = MAKEWORD(1,1);
WSAStartup(wVersionRequested, &wsaData);
sock = socket(AF_INET6, SOCK_DGRAM, 0);
if (sock < 0)
error("Fehler beim Anlegen des Sockets");
server.sin6_family = AF_INET6;
server.sin6_port = htons(6000);
server.sin6_addr = in6addr_any;
if (bind(sock, (struct sockaddr *) &server, sizeof(server)) == -1)
error("Fehler beim binden des Sockets");

Answer 1

This normally results from an attempt to bind to an address that is not valid for the local computer..
You should use PF_INET here instead of AF_INET. They have the same value, but you're not specifying an address family AF here, you're specifying a protocol family PF. This is just a style recommendation.
I would suggest to memset zero the below arrays,structures:
struct sockaddr_in6 server, client;
SOCKET sock;
char buffer[BUFFERSIZE];
LPTSTR recvBuff[1024];

Answer 2

Before you can use the sockaddr_in6 struct, you will have to memset it to zero:
memset(server, 0, sizeof(struct sockaddr_in6));
The reason is that the struct sockaddr_in6 structure contains other fields which you are not initializing (such as sin6_scope_id) and which might contain garbage.

Answer 3

I have faced the same error.
#askMish 's answer is quite right.I didn't understand it at the first place,however I find it out eventually.
This normally results from an attempt to bind to an address that is not valid for the local computer..
Normally we have our computer under some gateway.
If we run ipconfig we will find the IP address is 192.168.something.
So that's the IP we could use to bind in code.
While other should connect with the public IP(if you can surf Internet you have one for sure.) like 47.93.something if they are in the same LAN with you.
You need to find that IP at your gateway(possibly your family's route).

Answer 4

I had that same error code when calling bind() under windows.
The reason in my case was not the same as in the initial poster's code, but i guess other will have made the very same mistake as me:
I generated the local address on which i want the server to be bound locally using the inet_addr()-function.
I assigned this result to the local address structure struct sockaddr_in localaddr this way:
localaddr.sin_addr.s_addr = htonl(inaddr);
But inet_addr() already returns the address in byte-network-order, so the call htonl(inaddr) was wrong in my code and caused error 10049:
SOCKET tcpsock_bindlisten(unsigned short port, const char* bindaddr)
{
SOCKET srvsock = socket(PF_INET, SOCK_STREAM, IPPROTO_TCP);
unsigned long inaddr = bindaddr ? inet_addr(bindaddr) : INADDR_ANY;
struct sockaddr_in localaddr;
memset(&localaddr, 0, sizeof(struct sockaddr_in));
localaddr.sin_family = AF_INET;
localaddr.sin_port = htons(port);
// ERROR HERE! address returned from inet_addr is already in network-byte-order!
localaddr.sin_addr.s_addr = htonl(inaddr);
// CORRECT THIS WAY:
localaddr.sin_addr.s_addr = inaddr;
if (bind(srvsock, (struct sockaddr *) &localaddr, sizeof(localaddr)) != 0)
{
print_socketerror("tcpsock bind()");
return INVALID_SOCKET;
}
if (listen(srvsock, SVRSOCK_BACKLOG) != 0)
{
print_socketerror("tcpsock listen()");
return INVALID_SOCKET;
}
return srvsock;
}
When calling bind() using "all local interfaces" (INADDR_ANY) it worked, because of this coincidence INADDR_ANY == htonl(INADDR_ANY):
int main()
{
...
// this works for this special case:
SOCKET svrsock1 = tcpsock_bindlisten(4444, NULL);
// did not work!
SOCKET svrsock2 = tcpsock_bindlisten(5555, "192.168.0.123");
}