On Sat, Aug 29 2020, Stuart Henderson <s...@spacehopper.org> wrote:
> On 2020/08/27 15:28, Florian Obser wrote:
>> all heavy lifting done by sthen in unbound
>>
>> tests?
>
> ok with me. only tested lightly (the machine I normally use does DNS for
> other machines too so runs unbound).
>
> related, any idea what's happening here?
>
> unwind[51500]: fatal in main: could not bind to 127.0.0.1 or ::1 on port 53:
> Address already in use
>
> unbound is listening to *:53, but shouldn't other software be able to
> listen if bound to a specific address like 127.0.0.1:53? is this a bug
> somewhere or am I just missing something about UDP?
Once *:53 is bound you need SO_REUSEADDR to loosen the checks. ktrace
says unbound(8) uses this unconditionally. ChangeLog entry:
- Fix #531: Set SO_REUSEADDR so that the wildcard interface and a
more specific interface port 53 can be used at the same time, and
one of the daemons is unbound.
I think unwind could use the same treatment.
Note that using SO_REUSEADDR still prevents two unwind copies from
binding to 127.0.0.1:53 / [::1]:53 (for that to work you'd need
SO_REUSEPORT instead).
Thoughts? oks?
Index: unwind.c
===================================================================
RCS file: /d/cvs/src/sbin/unwind/unwind.c,v
retrieving revision 1.47
diff -u -p -p -u -r1.47 unwind.c
--- unwind.c 25 May 2020 16:52:15 -0000 1.47
+++ unwind.c 29 Aug 2020 17:07:49 -0000
@@ -726,6 +726,7 @@ open_ports(void)
{
struct addrinfo hints, *res0;
int udp4sock = -1, udp6sock = -1, error;
+ int opt = 1;
memset(&hints, 0, sizeof(hints));
hints.ai_family = AF_INET;
@@ -736,6 +737,9 @@ open_ports(void)
if (!error && res0) {
if ((udp4sock = socket(res0->ai_family, res0->ai_socktype,
res0->ai_protocol)) != -1) {
+ if (setsockopt(udp4sock, SOL_SOCKET, SO_REUSEADDR,
+ &opt, sizeof(opt)) == -1)
+ log_warn("setting SO_REUSEADDR on socket");
if (bind(udp4sock, res0->ai_addr, res0->ai_addrlen)
== -1) {
close(udp4sock);
@@ -751,6 +755,9 @@ open_ports(void)
if (!error && res0) {
if ((udp6sock = socket(res0->ai_family, res0->ai_socktype,
res0->ai_protocol)) != -1) {
+ if (setsockopt(udp6sock, SOL_SOCKET, SO_REUSEADDR,
+ &opt, sizeof(opt)) == -1)
+ log_warn("setting SO_REUSEADDR on socket");
if (bind(udp6sock, res0->ai_addr, res0->ai_addrlen)
== -1) {
close(udp6sock);
--
jca | PGP : 0x1524E7EE / 5135 92C1 AD36 5293 2BDF DDCC 0DFA 74AE 1524 E7EE
