Setting ""nsapi.dns-cache-size": 0" still left some of the DNS
caching code in. Add crude #if to remove all of it.
This allows one to save 429 bytes of flash and 48 bytes of RAM on
ARMC5 builds.
DNS resolver now counts how many sendto operations are successful
during one DNS server attempt cycle (attempting to contact DNS
servers from 0 to last index, including stack specific ones). If all
socket sendto operations fail, DNS resolution is aborted.
If one or more are successful, DNS resolution is continued until
total network attempts count is reached or all sendto operations
fails during a cycle.
- Set network stack to store event queue so that mbed::mbed_event_queue() call
is not needed every time call_in() is called
- Added dns state variables and enum (states are: created, initiated and cancelled)
- Corrected DNS response handling so that if DNS server returns that host name is
unknown the DNS query is not tried again
- Reorder mutexes in nsapi_dns_query_multiple_async()
- Created nsapi_dns_query_async_initiate_next() function to initiate the next
DNS query from the queue after delete of previous query
- Added dsn_timer_running variable to supervise DNS timer start/stop
- Changed cancel function to only mark query as deleted and moved deletion
to timer function. This allows to run socket close on DNS thread
- Added new nsapi error NSAPI_ERROR_TIMEOUT for DNS (and other) timeouts
- Changed mutexes to platform mutexes
- Removed not needed null check from delete
- Changed nsapi_dns_call_in_set() to use call_in_callback_cb_t and
added prototype to header
- Serialized the sending of multiple async DNS queries since limits on event
message box sizes
- Added timer function that supervises the total time used to make DNS query
and triggers socket timeouts
- Changed nsapi_error_t to new nsapi_value_or_error_t on interface headers
- Corrected wording of gethostbyname_async return values
- Clarified .json options
- Added a new data type for socket callback that can be used from interrupts
- Corrected variable limits to use INT32_MAX etc. defines
- Changed mallocs to new
- Optimized variable sizes on DNS_QUERY definition
- Changed call_in/call methods of the stack to callback provided by the stack
- Specified what are limitations for operations that are made in callback
- Added pure virtual class DNS that defines DNS operations
- Added cancel operation and unique ID to DNS request used in cancel
- Added DNS configuration options to netsocket/mbed_lib.json for retries,
response wait time and cache size
- Changed host name to use dynamic memory in DNS query list and cache,
set maximum length for the name to 255 bytes.
- Added mutex to asynchronous DNS
- Reworked retries: there is now total retry count and a server specific count
- Ignores invalid incoming UDP socket messages (DNS header is not valid), and retries DNS query
- Reworked DNS module asynchronous operation functions
- Corrected other review issues (nothrow new, missing free, missing mutex unlock etc.)
- Added non-blocking DNS interface to network interface and
network stack.
- Added caching of DNS replies.
- Added a network stack function to get DNS addresses from stack.
- Added call and call_in hooks to onboard network stack to
allow calling functions from onboard stack context.
- Added support to call and call_in functions to LWIP and
Nanostack.
- Disabled LWIP DNS translator with the exception of DNS
address storage used in DNS address get.
Documentation states that nsapi_dns_query_multiple returns the number of
addresses found on success - it was returning 0.
Overloads using SocketAddress are relying on the return value, meaning
those calls didn't work at all.
Fixes#5921.
Observed during investigation of
https://github.com/ARMmbed/mbed-os/issues/4246 - DNS queries sent
the entire buffer, not just the bit filled in.
Inefficient, especially for 6LoWPAN, and a security hole - the trailing
data could be previously-used heap.
nsapi_error_t - enum of errors or 0 for NSAPI_ERROR_OK
nsapi_size_t - unsigned size of data that could be sent
nsapi_size_or_error_t - either a non-negative size or negative error
Replace Comodo and OpenDNS IPv4 servers with Google and DNS.WATCH IPv6
servers, so IPv6-only devices (eg 6LoWPAN) have a default.
3 IPv4 resolvers should be plenty - existing code doesn't remember which
one last worked, so if early list entries were unreachable performance
would be consistently bad anyway. Replacing two entries avoids
increasing image size and RAM consumption.
On an IPv6-only or IPv4-only system, the sendto() for the wrong type of
address should fail immediately - change loop to move on to the next
server for any sendto() error.
Tero Jääskö
Mika Leppänen
Kevin Bracey
Martin Kojtal
Christopher Haster
Bartek Szatkowski