(Cc'ing Michael Kerrisk)
On Wed, Mar 22, 2017 at 10:18 PM, Eric Dumazet <eric.duma...@gmail.com> wrote:
> On Thu, 2017-03-23 at 13:22 +1100, Daurnimator wrote:
>> On 9 March 2017 at 14:10, Daurnimator <q...@daurnimator.com> wrote:
>> > When debugging https://github.com/daurnimator/lua-http/issues/73 which
>> > uses https://github.com/wahern/dns we ran into an issue where modern
>> > linux kernels return EINVAL if you try and re-use a udp socket.
>> > The issue seems to occur if you go from a local destination ip to a
>> > non-local one.
>>
>> Did anyone get a chance to look into this issue?
>
> I believe man page is not complete.
>
> A disconnect is needed before another connect()
Is it? Making connect() reentrant is reasonable for connection-less
protocol like UDP, but I don't dig POSIX for the details. If so we need
something like below...
--- a/net/ipv4/datagram.c
+++ b/net/ipv4/datagram.c
@@ -40,7 +40,7 @@ int __ip4_datagram_connect(struct sock *sk, struct
sockaddr *uaddr, int addr_len
sk_dst_reset(sk);
oif = sk->sk_bound_dev_if;
- saddr = inet->inet_saddr;
+ saddr = inet->inet_saddr = 0;
if (ipv4_is_multicast(usin->sin_addr.s_addr)) {
if (!oif)
oif = inet->mc_index;
