examples/dtls-echo: Cleaning and upgrade to sock

Due to all the changes, this is basically a new version for this
example. The main benefit is the use of sock_udp but also the client
side is now more robust and reliable.

examples/dtls-echo/Makefile

@@ -9,8 +9,8 @@ RIOTBASE ?= $(CURDIR)/../..
 
 # TinyDTLS only has support for 32-bit architectures ATM
 BOARD_BLACKLIST := arduino-duemilanove arduino-mega2560 arduino-uno chronos \
-                   msb-430 msb-430h telosb waspmote-pro wsn430-v1_3b wsn430-v1_4 \
-                   z1
+                   mips-malta msb-430 msb-430h pic32-clicker pic32-wifire \
+				   telosb waspmote-pro wsn430-v1_3b wsn430-v1_4 z1
 
 BOARD_INSUFFICIENT_MEMORY := airfy-beacon b-l072z-lrwan1 bluepill calliope-mini \
                              cc2650-launchpad cc2650stk maple-mini \
@@ -24,51 +24,54 @@ BOARD_INSUFFICIENT_MEMORY := airfy-beacon b-l072z-lrwan1 bluepill calliope-mini
 # NOTE: 6LoWPAN will be included if IEEE802.15.4 devices are present
 USEMODULE += gnrc_netdev_default
 USEMODULE += auto_init_gnrc_netif
-# Specify the mandatory networking modules for IPv6 and sUDP
+# Specify the mandatory networking modules for IPv6 and UDP
 USEMODULE += gnrc_ipv6_router_default
-USEMODULE += gnrc_udp
-# Add a routing protocol
+USEMODULE += gnrc_sock_udp
+# Add a routing protocol (optional)
 USEMODULE += gnrc_rpl
-# This application dumps received packets to STDIO using the pktdump module
-USEMODULE += gnrc_pktdump
+
 # Additional networking modules that can be dropped if not needed
 USEMODULE += gnrc_icmpv6_echo
 # Add also the shell, some shell commands
 USEMODULE += shell
 USEMODULE += shell_commands
 USEMODULE += ps
 
-#TinyDTLs (crypto.c) made use of pthread
- ifneq ($(BOARD),native)
-   USEMODULE += pthread
- endif
+USEPKG += tinydtls
 
-# Comment this out to disable code in RIOT that does safety checking
-# which is not needed in a production environment but helps in the
-# development process:
-CFLAGS += -DDEVELHELP
+# Uncomment to redefine port. Default: DTLS port (20220).
+#DTLS_PORT = 20220
+#CFLAGS += -DDTLS_DEFAULT_PORT=$(DTLS_PORT)
 
-# NOTE: Add the package for TinyDTLS
-USEPKG += tinydtls
+# NOTE: If not cipher suite is selected, DTLS_PSK is used by default.
+# This adds support for TLS_PSK_WITH_AES_128_CCM_8
+# CFLAGS += -DDTLS_PSK
+# This adds support for TLS_ECDHE_ECDSA_WITH_AES_128_CCM_8
+# CFLAGS += -DDTLS_ECC
 
-# NOTE: Those are taken from TinyDTLS. As the original Makefiles are
-#      overwitten is a good idea to preserve them here.
-CFLAGS += -DDTLSv12 -DWITH_SHA256
+# Define the log entry for tinydtls.
+# Values: 0:EMERG (Default), 1:ALERT 2:CRIT 3:WARN 4:NOTICE 5:INFO 6:DEBUG
+# TINYDTLS_LOG = 0
 
-# NOTE: This adds support for TLS_PSK_WITH_AES_128_CCM_8
-CFLAGS += -DDTLS_PSK
+# Enable this line for setting tinyDTLS in debug mode.
+# This overrides TINYDTLS_LOG to 6
+# CFLAGS += -DTINYDTLS_DEBUG
 
-# NOTE: This adds support for TLS_ECDHE_ECDSA_WITH_AES_128_CCM_8
-CFLAGS += -DDTLS_ECC
+# dtls-client.c will generate a "CoAP get /riot/value" message instead of
+# sending the user input (ASCII).
+# dtls-server.c will display hexadecimal characters instead of ASCII.
+#CFLAGS += -DCOAP_MSG_SPOOF
 
-# NOTE: If enabled TinyDTLS' log are disabled (if memory is a issue).
-# WARNING: Sometimes the log leads to Stack pointer corrupted.
-#          The reason is not identified yet.
-#          If said issue appears, enable this line.
-#CFLAGS += -DNDEBUG
+# FIXME: This is a temporary patch
+#        TinyDTLS <= 0.8.6 requires around 426 bytes in RAM.
+CFLAGS += -DTHREAD_STACKSIZE_MAIN=\(3*THREAD_STACKSIZE_DEFAULT\)
+# TINYDTLS_EXTRA_BUFF can be used for increasing the server stack memory.
+# CFLAGS += -DTINYDTLS_EXTRA_BUFF=\(512\)
 
-# NOTE: The configuration for socket or non-socket  communication in TinyDTLS.
-CFLAGS += -DWITH_RIOT_GNRC
+# Comment this out to disable code in RIOT that does safety checking
+# which is not needed in a production environment but helps in the
+# development process:
+CFLAGS += -DDEVELHELP
 
 # Change this to 0 show compiler invocation lines by default:
 QUIET ?= 1

examples/dtls-echo/README.md

@@ -1,77 +1,72 @@
-# dtls_echo
+# dtls_echo example
 
-This example  shows you how to use TinyDTLS with the non-socket approach.
+This example shows you how to use TinyDTLS with the non-socket approach.
 
-This code  is based on  ../gnrc_networking and ../gnrc_tftp.
-Is a good idea to read their README.md's for any doubt of how making the
-testings.
+## SOCK vs. Socket
 
-## SOCKET vs. Non-socket (GNRC)
-
-This example is configured to use the GNRC instead of  sockets (over GNRC).
-At the moment, the configuration must be done manually in the Makefile of
-this project.
+This example is configured to use socks instead of sockets (over GNRC). It's
+possible to use sockets (again, over GNRC), which give a more similar approach
+to the original Linux version of TinyDTLS. However, is not tested yet.
 
 ## Fast configuration (Between RIOT instances):
 
 Preparing the logical interfaces:
 
-    ./../../dist/tools/tapsetup/tapsetup --create 2
+```
+./../../dist/tools/tapsetup/tapsetup --create 3
+```
 
 For the server instance:
 
-    make all; PORT=tap1 make term
-    dtlss start
-    ifconfig
+```
+PORT=tap1 make all term
+dtlss start
+ifconfig
+```
 
 Do not forget to copy the IPv6 addresses!
 
 For the client:
 
-    PORT=tap0 make term
-    dtlsc <IPv6's server address> "DATA TO DATA TO DATA!"
+```
+PORT=tap0 make term
+dtlsc <IPv6's server address> "DATA to send under encrypted channel!"
+```
 
 # Testings
 ## Boards
 
-Those boards that do not support  the `../gnrc_networking` example are included
-in the `BOARD_INSUFFICIENT_MEMORY`, plus the  board `cc2650stk`.
+Boards that do not support the `../gnrc_networking` example are included
+in the `BOARD_INSUFFICIENT_MEMORY`, plus the board `cc2650stk`.
 
 There are certain boards that are having issues with `crypto.c` and
 `dtls_time.h` Which for now are in the the `BOARD_BLACKLIST`.
 
 The boards that requires `periph_conf.h` are not tested.
 
-Boards with problem type 1 (`crypto.c`):
-    z1
-    wsn430-v1_4
-    wsn430-v1_3b
-    waspmote-pro
-    msb-430h
-    msb-430
-    chronos
-    arduino-mega2560
-
-Boards with problem type 2 (`dtls_time.h`):
-    cc2538dk
-    msbiot
-    telosb
-
-Boards with problem type 3 (Redifinition):
-    saml21-xpro
-    samr21-xpro
-    arduino-uno
-    arduino-duemilanove
-
-NOTE: Those on type 1 can be benefit of the following PR:
-https://github.com/RIOT-OS/RIOT/issues/2360
-However, there are still issues to fix.
-
-NOTE: Those on type 2 can be fixed with the patch at
-https://github.com/RIOT-OS/RIOT/pull/5974
-
-## FIT-LAB
-
-The code has been tested in the FIT-LAB with M3 motes.
-However, erros can occurrs. Enabling the line `CFLAGS += -DNDEBUG` in
-the `Makefile` reduces the risk.
+The code has been tested in the FIT IOT-LAB tesbed with the remote
+`iotlab-m3` and `iotlab-a8-m3` boards and with local `samr21-xpro` boards.
+
+## Handling the static memory allocation
+
+TinyDTLS for RIOT O.S. is using the `sys/memarray` module and therefore there
+are certain limits. Said resources are defined in
+`pkg/tinydtls/platform-specific/riot_boards.h`, but can be overwritten at
+compilation time. Their default values are considered for having two DTLS
+contexts (for purpose of DTLS renegotiation).
+
+The resources handled by memarray are:
+* `DTLS_CONTEXT_MAX` (default 2) The maximum number of DTLS  context at the
+   same time.
+* `DTLS_PEER_MAX` (default 1) The maximum number DTLS peers (i.e. sessions).
+* `DTLS_HANDSHAKE_MAX` (default 1) The maximum number of concurrent DTLS handshakes.
+* `DTLS_SECURITY_MAX` (the sum of the previous two) The maximum number of
+   concurrently used cipher keys.
+* `DTLS_HASH_MAX` (Default: `3 * DTLS_PEER_MAX`) The maximum number of hash
+  functions that can be used in parallel.
+
+## Handling retransmissions
+
+By default, the number of transmissions of any DTLS record is settled to just
+one. This can be handled by DTLS_DEFAULT_MAX_RETRANSMIT (defined in
+`pkg/tinydtls/platform-specific/riot_boards.h`).