mdns library deinitialization destroys internal structures including action queue. if an event (e.g. network update) received
after some essential stucture is destoyed, an unexpected behavour might be introduced (e.g. crash of adding the event notification
to the action queue which was already destroyed
Closes WIFI-1485
mdns module store local copy of esp_netif for common interfaces,
but it was correctly initialized only when interface started.
If the event were missed (e.g. mdns_init after interface start)
the local copy wouldn't be initialized. Fixed by restoring the local
copy.
Closes WIFI-1538
esp32s2beta: Merge support to master
Closes IDF-513, IDF-756, IDF-758, IDF-999, IDF-753, IDF-749, IDF-754, IDF-840, and IDF-755
See merge request espressif/esp-idf!6100
tcpip_adapter_dhcpc_get_status() returns the actual internal value of dhcp client without any locking or TCP/IP stack context call, so when CONNECTED event fired with default settings it started DHCP client in TCP/IP stack context and at the same time mdns event handler checking actual DHCP state, which could still be INIT (not STARTED). Purpose of this check is to enable PCB if DHCP was stopped before setting network interface up (typically static IP settings), so the solutin is to check against TCPIP_ADAPTER_DHCP_STOPPED state
Issue: MDNS server initially sends probing packets to resolve naming confilicts with already registered service instances. In case of a conflict, instance name is altered and probing restarts. Original instance however wasnnot removed from the structure and upon service removal only one entry was removed and a dangling service might have been kept in the structure to bring about a crash.
Resolution: Keep only one instance of a service in the probing structure.
Closes IDF-498
possible race condition: user task runs mdns_init, which enables pcbs while mdns-task already created could execute enable/disable of the same pcbs if an appropriate system event received
mnds_free() initiates stop and delete timer tasks, which after locking the mutex could lead to a dead lock in case timer task executed before deleting the task, as it would wait indefinitelly for unlocking the mutex. This condition is fixed by calling _mdns_stop_timer without locking the mutex, because there's no need to protect any data when stopping and deleting the timer task
Closes https://github.com/espressif/esp-idf/issues/1696
Issue: mdns_service_add API allocates and queues an action to be processed in mdns task context; when allocation or queueing fails, allocated structure needs to be freed. Function _mdns_free_service did not only fee all the structures, but also updates packet data.
Resolution: Moved removal of packet data outside of _mdns_free_service function.
packets scheduled to transmit are pushed to action queue and removed from tx_queue_head structure, which is searched for all remaining services and while service is removed, then service questions/asnwers are also removed from this structure. This update fixes possible crash when packet is pushed to action queue, and when service is removed, its answers are removed from tx_queue_head, but not from action queue. this could lead to a crash when the packet is poped from action queue containing questions/answers to already removed (freed) service
Closes IDF-504
mdns_search_once_t::lock is used to synchronize tasks (taken by one
task and given by the other) so it should not be a mutex.
Convert to semaphore, and rename to indicate its purpose.
