dhcpcd-discuss

On 17/05/2018 01:55, Moritz Warning wrote:
> On 05/16/2018 09:37 PM, Roy Marples wrote:
> > On 16/05/2018 17:01, Moritz Warning wrote:
> > > On 05/16/2018 10:28 AM, Roy Marples wrote:
> > > > Hi Moritz
> > > >
> > > > On 15/05/2018 23:37, Moritz Warning wrote:
> > > > > from dhcpcd 7.0.4-1 on Arch Linux gives me "dhcp6_listen: Address already in use" and exits.
> > > > > The problem appears when connecting to my WLAN using wicd 1.7.4-1:
> >
> >
> > > > > May 15 23:26:22 brick dhcpcd[18975]: forked to background, child pid 19022
> > > > > May 15 23:26:22 brick dhcpcd[18975]: dhcp6_listen: Address already in use
> >
> > Attached patch should solve this error.
> >
> > > > > May 15 23:26:22 brick dhcpcd[19025]: sending signal ALRM to pid 19022
> > > > > May 15 23:26:22 brick dhcpcd[19025]: waiting for pid 19022 to exit
> > > > > May 15 23:26:22 brick dhcpcd[19022]: received SIGALRM, releasing
> >
> > Something called `dhcpcd -k` here which releases the lease as you see.
> > I think that is the real error - does wicd do that?
> Yes, wicd calls "dhcpcd -k" when it detects no ip address on the specified interface.
>
> > Can you let me know if the patch addresses the listen error please?
> >
> > Thanks
> >
> > Roy
>
> The error still appears.

That is odd.
Try this new patch which logs a lot more, if you post a new log it 
should say which address is failing.

> But the connection also fails sometimes when the error is not showing up.
> It is that way even without the patch. So it might not be the cause.
>
> Is this "sending signal ALRM to pid 19022" part of the shutdown sequence of dhcpcd?

Yes. because dhcpcd itself logged sending signal on a different pid, 
it's clear something called `dhcpcd -k` to shut it down. This is likely 
wicd and likely because dhcpcd forked when getting a working IPv6 
address an wicd expects a working IPv4 address.

Try adding `waitip 4` to /etc/dhcpcd.conf

Roy

diff --git a/src/dhcp6.c b/src/dhcp6.c
index 399f3785..9d522dda 100644
--- a/src/dhcp6.c
+++ b/src/dhcp6.c
@@ -3611,6 +3611,8 @@ dhcp6_listen(struct dhcpcd_ctx *ctx, struct ipv6_addr *ia)
 	struct sockaddr_in6 sa;
 	int n, s;
 
+	loginfox("LISTENING TO %s", ia == NULL ? NULL : ia->saddr);
+
 #define SOCK_FLAGS	SOCK_CLOEXEC | SOCK_NONBLOCK
 	s = xsocket(PF_INET6, SOCK_DGRAM | SOCK_FLAGS, IPPROTO_UDP);
 #undef SOCK_FLAGS
diff --git a/src/ipv6.c b/src/ipv6.c
index 82cf71b6..9a4e6d81 100644
--- a/src/ipv6.c
+++ b/src/ipv6.c
@@ -1175,8 +1175,11 @@ ipv6_handleifa(struct dhcpcd_ctx *ctx,
 	}
 
 	if (ia != NULL) {
-		ipv6nd_handleifa(cmd, ia, pid);
-		dhcp6_handleifa(cmd, ia, pid);
+		/* Don't run handlers if forked from the DaD callback */
+		if (!(ctx->options & DHCPCD_FORKED)) {
+			ipv6nd_handleifa(cmd, ia, pid);
+			dhcp6_handleifa(cmd, ia, pid);
+		}
 
 		/* Done with the ia now, so free it. */
 		if (cmd == RTM_DELADDR)