Re: [lwip-users] dhcp and mdns responder

[Manu Abraham]

Replying to my own post:

Attached wireshark capture screencap:

The PC host 192.168.1.34 sends out a mDNS question.

I was expecting that, the udp_recv() within

/**
 * @ingroup mdns
 * Initiate MDNS responder. Will open UDP sockets on port 5353
 */
void
mdns_resp_init(void)

would be receiving the mDNS question. But in fact, it does not, when
used in a mdns_example_init() from mdns_example.c context.

So, I started looking to use udp_recv outside of mdns.c, but then the
udp_pcb is static.

static struct udp_pcb *mdns_pcb;


Is something amiss in what I have understood ? Am I going on a wrong track ?


Thanks for any pointers.

Manu



On Sun, Aug 30, 2020 at 10:10 PM Manu Abraham <abraham.manu@gmail.com> wrote:
>
> Greetings,
>
> Trying to get mdns from lwip/apps working.
>
> I have the following code running:
>
> void netpnp_thread(void *arg)
> {
>     struct netif *netif = arg;
>
>     xSemaphoreTake(sem_mdns, portMAX_DELAY);
>     osDelay(1000);
>
>     igmp_report_groups(netif);
>     mdns_example_init();
>
>     while (1);
> }
>
>
> With that mdns works with the mdns_example_init() shamelessly copied
> from mdns_example.c, DHCP client has already created a multicast group
> with address 224.0.0.1
>
> This is verified from the igmp debug log.
>
> My question is thus; How and when should an announcement be done ?
> Does the browser application request the announcement request ?
> If so, how should that be handled ?
>
>
> Thanks,
>
> Manu
>
>
>  (292) StartThread:
> igmp_init: initializing
>  (257) Netif_Config: Configuring Network
> igmp_start: starting IGMP processing on if 24000234
> igmp_lookup_group: allocated a new group with address 224.0.0.1 on if 24000234
>  (342) dhcp_thread:
>  DHCP state       : 132
>  DHCP state       : SELECTING
>  DHCP state       : CHECKING
> igmp_report_groups: sending IGMP reports on if 24000234
>  DHCP state       : BOUND
>
>  IPv4 Address     : 192.168.1.33
>  IPv4 Subnet mask : 255.255.255.0
>  IPv4 Gateway     : 192.168.1.1
>
>  Lease period: 86400s, Renew in: 43200s, Rebind in: 75600s
>
>  (330) print_dhcp_state: DHCP Bound
> igmp_report_groups: sending IGMP reports on if 24000234
> igmp_lookup_group: allocated a new group with address 224.0.0.251 on if 
> 24000234
> igmp_joingroup_netif: join to new group: 224.0.0.251
> igmp_timeout: report membership for group with address 224.0.0.251 on
> if 24000234
> MDNS: Responding with A record
> MDNS: Responding with SRV record
> MDNS: Responding with TXT record
> MDNS: Sending packet, len=106, unicast=0
> MDNS: Responding with A record
> MDNS: Responding with SRV record
> MDNS: Responding with TXT record
> MDNS: Sending packet, len=106, unicast=0
> MDNS: Responding with A record
> MDNS: Responding with SRV record
> MDNS: Responding with TXT record
> MDNS: Sending packet, len=106, unicast=0
> MDNS: Responding with A record
> MDNS: Responding with v4 PTR record
> MDNS: Responding with service type PTR record
> MDNS: Responding with service name PTR record
> MDNS: Responding with SRV record
> MDNS: Responding with TXT record
> MDNS: Sending packet, len=184, unicast=0
> mdns status[netif 0]: 1