[haiku-development] Re: UDP bug
- From: "Axel Dörfler" <axeld@xxxxxxxxxxxxxxxx>
- To: haiku-development@xxxxxxxxxxxxx
- Date: Sun, 10 Jan 2010 13:11:55 +0100
Hi Oliver,
Oliver Tappe <zooey@xxxxxxxxxxxxxxx> wrote:
> On 2010-01-09 at 18:36:12 [+0100], Axel Dörfler <axeld@xxxxxxxxxxxxxxxx>
> > wrote:
> > when I connect() a UDP socket to a peer in Haiku, no matter if I
> > bound
> > it implicitly or explicitly to INADDR_ANY, it's local address stays
> > bound to INADDR_ANY, whereas it is resolved to a local address in
> > Linux.
> > I would tend to think that our behaviour is indeed wrong, but the
> > documentation I read isn't as explicit about this as I would want
> > it to
> > be.
> Well, I think Stevens' Unix Network Programming Vol I, Chapter 9.11
> is pretty
> explicit when it states that a connected UDP socket receives only
> datagrams
> "destined to the connected socket's local address (IP and port)". I
> think
> this supports your interpretation that we are doing it incorrectly.
Interestingly, we obviously correctly restrict the sender to the
connected address.
> Shall I have a look at it tomorrow, or would you prefer doing that
> yourself?
I already looked into it a bit, but I'm afraid one needs a stack
function for this to work (or otherwise use SIOCGETRT). Feel free to
look into it, if you want to -- if not I could do it, too.
> Anything specific that triggered your question (a testcase)?
I ran into the problem of not knowing the outgoing interface in UDP --
I created a work-around for Haiku via SIOCGETRT, only to later found
out that at least Linux does not support this.
I then read the connect() description again, and it looked like it
would do what I needed, but it didn't work under Haiku. I've attached a
small test application that you can use to reproduce the problem; we
should probably put it into our repository.
Bye,
Axel.
/*
* Copyright 2010, Axel Dörfler, axeld@xxxxxxxxxxxxxxxxx
* This file may be used under the terms of the MIT License.
*/
#include <arpa/inet.h>
#include <netinet/in.h>
#include <sys/socket.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
int
main(int argc, char** argv)
{
const char* peerAddress = "192.168.0.1";
if (argc > 1)
peerAddress = argv[1];
int fd = socket(AF_INET, SOCK_DGRAM, 0);
if (fd < 0)
return 1;
#if 1
sockaddr_in addr;
addr.sin_family = AF_INET;
addr.sin_addr.s_addr = INADDR_ANY;
addr.sin_port = htons(8888);
if (bind(fd, (sockaddr*)&addr, sizeof(addr)) != 0)
perror("bind");
sockaddr ours;
socklen_t ourLength = sizeof(sockaddr);
if (getsockname(fd, &ours, &ourLength) != 0)
perror("getsockname");
else {
printf("After bind: local address %s (%u)\n",
inet_ntoa(((sockaddr_in&)ours).sin_addr),
ntohs(((sockaddr_in&)ours).sin_port));
}
#endif
sockaddr_in peer;
peer.sin_family = AF_INET;
peer.sin_addr.s_addr = inet_addr(peerAddress);
peer.sin_port = htons(8888);
if (connect(fd, (sockaddr*)&peer, sizeof(peer)) != 0)
perror("connect");
ourLength = sizeof(sockaddr);
if (getsockname(fd, &ours, &ourLength) != 0)
perror("getsockname");
else {
printf("After connect: local address %s (%u)\n",
inet_ntoa(((sockaddr_in&)ours).sin_addr),
ntohs(((sockaddr_in&)ours).sin_port));
}
char buffer[256];
if (argc > 2 && !strcmp(argv[2], "recv")) {
ssize_t bytesReceived = recv(fd, buffer, sizeof(buffer), 0);
if (bytesReceived > 0) {
buffer[bytesReceived] = 0;
printf("received: %s\n", buffer);
} else
perror("recv");
} else {
if (argc > 2)
send(fd, argv[2], strlen(argv[2]), 0);
fgets(buffer, sizeof(buffer), stdin);
}
close(fd);
return 0;
}
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