On 04/21/2017 03:31 PM, Cristian Morales Vega wrote:
On 13 February 2017 at 15:42, Rafał Miłecki <[email protected]> wrote:
From: Rafał Miłecki <[email protected]>
When we receive PTR question it includes hostname (instance), e.g.:
mdnsd: parse_question (391): Q -> PTR lede._http._tcp.local
First of all we should check if it matches hostname we use before trying
to reply. Secondly service_reply expects service with domain appended
(without hostname/instance) so we need to strip received string out of
hostname before passing it.
Signed-off-by: Rafał Miłecki <[email protected]>
---
dns.c | 14 ++++++++++++--
1 file changed, 12 insertions(+), 2 deletions(-)
diff --git a/dns.c b/dns.c
index 91434f2..dac6f2c 100644
--- a/dns.c
+++ b/dns.c
@@ -367,9 +367,19 @@ parse_question(struct interface *iface, char *name, struct
dns_question *q)
break;
case TYPE_PTR:
- if (!strcmp(name, sdudp))
+ if (!strcmp(name, sdudp)) {
service_announce_services(iface, announce_ttl);
- service_reply(iface, name, announce_ttl);
+ } else {
+ /* First dot separates instance name from the rest */
+ char *dot = strchr(name, '.');
+ /* Length of queried instance */
+ size_t len = dot ? dot - name : 0;
+
+ /* Make sure it's query for the instance name we use */
+ if (len && len == strlen(mdns_hostname) &&
+ !strncmp(name, mdns_hostname, len))
+ service_reply(iface, dot + 1, announce_ttl);
+ }
break;
case TYPE_AAAA:
Isn't this failing to take into account the case when there is no hostname?
With 480d7bc74eba20c03875aa06c1c25dbdb98e0b12 running on SKWB8:
$ sudo systemctl restart avahi-daemon
$ avahi-browse -ck '_ssh._tcp'
$ avahi-browse -tk '_ssh._tcp'
+ enp0s25 IPv6 linux-vf7n _ssh._tcp
local
+ enp0s25 IPv4 linux-vf7n _ssh._tcp
local
$ avahi-browse -atk
+ enp0s25 IPv6 SKWB8
_skhttp._tcp local
+ enp0s25 IPv6 SKWB8
_skjitter._tcp local
+ enp0s25 IPv6 SKWB8 _ssh._tcp
local
+ enp0s25 IPv6 linux-vf7n _ssh._tcp
local
+ enp0s25 IPv4 linux-vf7n _ssh._tcp
local
+ enp0s25 IPv4 SKWB8
_skhttp._tcp local
+ enp0s25 IPv4 SKWB8
_skjitter._tcp local
+ enp0s25 IPv4 SKWB8 _ssh._tcp
local
+ enp0s25 IPv6 linux-vf7n
_sftp-ssh._tcp local
+ enp0s25 IPv6 linux-vf7n [14:da:e9:f7:1b:95]
_workstation._tcp local
+ enp0s25 IPv4 linux-vf7n
_sftp-ssh._tcp local
+ enp0s25 IPv4 linux-vf7n [14:da:e9:f7:1b:95]
_workstation._tcp local
$ avahi-browse -ck '_ssh._tcp'
+ enp0s25 IPv6 SKWB8 _ssh._tcp
local
+ enp0s25 IPv6 linux-vf7n _ssh._tcp
local
+ enp0s25 IPv4 SKWB8 _ssh._tcp
local
+ enp0s25 IPv4 linux-vf7n _ssh._tcp
local
$ avahi-browse -tk '_ssh._tcp'
+ enp0s25 IPv6 SKWB8 _ssh._tcp
local
+ enp0s25 IPv6 linux-vf7n _ssh._tcp
local
+ enp0s25 IPv4 SKWB8 _ssh._tcp
local
+ enp0s25 IPv4 linux-vf7n _ssh._tcp
local
$
When running with -d umdns says things like
mdnsd: parse_question (366): Q -> PTR _skhttp._tcp.local
mdnsd: parse_question (366): Q -> PTR _skhttp._tcp.local
mdnsd: parse_question (366): Q -> PTR _skhttp._tcp.local
mdnsd: parse_question (366): Q -> PTR _skhttp._tcp.local
mdnsd: parse_question (366): Q -> PTR _services._dns-sd._udp.local
mdnsd: dns_send_answer (178): A <- A SKWB8.local
mdnsd: dns_send_answer (178): A <- AAAA SKWB8.local
mdnsd: dns_send_answer (178): A <- PTR _services._dns-sd._udp.local
mdnsd: dns_send_answer (178): A <- PTR _skhttp._tcp.local
mdnsd: dns_send_answer (178): A <- SRV SKWB8._skhttp._tcp.local
mdnsd: dns_send_answer (178): A <- TXT SKWB8._skhttp._tcp.local
mdnsd: dns_send_answer (178): A <- PTR _services._dns-sd._udp.local
mdnsd: dns_send_answer (178): A <- PTR _skjitter._tcp.local
mdnsd: dns_send_answer (178): A <- SRV SKWB8._skjitter._tcp.local
mdnsd: dns_send_answer (178): A <- TXT SKWB8._skjitter._tcp.local
mdnsd: dns_send_answer (178): A <- PTR _services._dns-sd._udp.local
mdnsd: dns_send_answer (178): A <- PTR _ssh._tcp.local
mdnsd: dns_send_answer (178): A <- SRV SKWB8._ssh._tcp.local
mdnsd: dns_send_answer (178): A <- TXT SKWB8._ssh._tcp.local
So it's seems it's not answering to the _ssh._tcp queries.
After reading your comment & analyzing the code: yes. I expect this to break
support for queries you mentioned.
My problem is that even without this commit or my local fix avahi-browse
still doesn't detect services announced by umdns. I can see answers being
sent so I assume there is something wrong with them.
I've to debug it further.
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