tests: add test to test RDNSS option handling

tests/gnrc_ipv6_nib_dns/Makefile

@@ -0,0 +1,45 @@
+include ../Makefile.tests_common
+
+RIOTBASE ?= $(CURDIR)/../..
+
+export TAP ?= tap0
+
+USEMODULE += sock_dns
+USEMODULE += gnrc_sock_udp
+USEMODULE += gnrc_ipv6_default
+USEMODULE += gnrc_ipv6_nib_dns
+# use Ethernet as link-layer protocol
+ifeq (native,$(BOARD))
+  TERMFLAGS ?= $(TAP)
+else
+  ETHOS_BAUDRATE ?= 115200
+  CFLAGS += -DETHOS_BAUDRATE=$(ETHOS_BAUDRATE)
+  TERMDEPS += ethos
+  TERMPROG ?= sudo $(RIOTTOOLS)/ethos/ethos
+  TERMFLAGS ?= $(TAP) $(PORT) $(ETHOS_BAUDRATE)
+endif
+USEMODULE += auto_init_gnrc_netif
+
+USEMODULE += shell
+USEMODULE += shell_commands
+
+USEMODULE += posix_inet
+
+LOW_MEMORY_BOARDS := nucleo-f334r8 msb-430 msb-430h
+
+ifeq ($(BOARD),$(filter $(BOARD),$(LOW_MEMORY_BOARDS)))
+    CFLAGS += -DGNRC_PKTBUF_SIZE=512 -DCONFIG_GNRC_NETIF_IPV6_ADDRS_NUMOF=2 \
+              -DGNRC_NETIF_IPV6_GROUPS_NUMOF=2 -DGNRC_IPV6_NIB_NUMOF=1 \
+              -DNRC_IPV6_NIB_OFFL_NUMOF=1
+endif
+
+# The test requires some setup and to be run as root
+# So it cannot currently be run
+TEST_ON_CI_BLACKLIST += all
+
+.PHONY: ethos
+
+ethos:
+	$(Q)env -u CC -u CFLAGS make -C $(RIOTTOOLS)/ethos
+
+include $(RIOTBASE)/Makefile.include

tests/gnrc_ipv6_nib_dns/Makefile.board.dep

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+# Put board specific dependencies here
+ifeq (native,$(BOARD))
+  USEMODULE += netdev_tap
+else
+  USEMODULE += stdio_ethos
+endif

tests/gnrc_ipv6_nib_dns/Makefile.ci

@@ -0,0 +1,28 @@
+BOARD_INSUFFICIENT_MEMORY := \
+    arduino-duemilanove \
+    arduino-leonardo \
+    arduino-mega2560 \
+    arduino-nano \
+    arduino-uno \
+    atmega1284p \
+    atmega328p \
+    derfmega128 \
+    i-nucleo-lrwan1 \
+    mega-xplained \
+    microduino-corerf \
+    msb-430 \
+    msb-430h \
+    nucleo-f030r8 \
+    nucleo-f031k6 \
+    nucleo-f042k6 \
+    nucleo-f303k8 \
+    nucleo-l031k6 \
+    nucleo-l053r8 \
+    stm32f030f4-demo \
+    stm32f0discovery \
+    stm32l0538-disco \
+    telosb \
+    waspmote-pro \
+    wsn430-v1_3b \
+    wsn430-v1_4 \
+    #

tests/gnrc_ipv6_nib_dns/README.md

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+# Overview
+
+This test utilizes [scapy] to test GNRC's RDNSS option implementation for
+router advertisements
+
+To test, compile and flash the application to any board of your liking (since
+`ethos` is used to communicate with non-native boards it really doesn't matter
+as long as the application fits and the board is supported).
+
+    make flash
+
+And run the tests using
+
+```
+sudo make test
+```
+
+Note that root privileges are required since `scapy` needs to construct Ethernet
+frames to properly communicate over the TAP interface.
+
+The test passes on success, on failure an exception is shown.
+
+[scapy]: https://scapy.readthedocs.io/en/latest/

tests/gnrc_ipv6_nib_dns/main.c

@@ -0,0 +1,82 @@
+/*
+ * Copyright (C) 2017 Kaspar Schleiser <kaspar@schleiser.de>
+ *
+ * This file is subject to the terms and conditions of the GNU Lesser
+ * General Public License v2.1. See the file LICENSE in the top level
+ * directory for more details.
+ */
+
+/**
+ * @ingroup     tests
+ * @{
+ *
+ * @file
+ * @brief       sock DNS client test application
+ *
+ * @author      Kaspar Schleiser <kaspar@schleiser.de>
+ *
+ * @}
+ */
+
+#include <stdio.h>
+#include <string.h>
+
+#include <arpa/inet.h>
+
+#include "net/sock/dns.h"
+#include "shell.h"
+
+#define MAIN_QUEUE_SIZE     (8)
+static int _dns(int argc, char **argv);
+
+static const shell_command_t _shell_commands[] = {
+    { "dns", "configures and requests a DNS server", _dns },
+    { NULL, NULL, NULL },
+};
+static char _shell_buffer[SHELL_DEFAULT_BUFSIZE];
+
+static void _usage(char *cmd)
+{
+    printf("usage: %s server\n", cmd);
+}
+
+static int _dns_server(int argc, char **argv)
+{
+    int res = (argc < 2);
+
+    if (!res) {
+        if (sock_dns_server.port > 0) {
+            char addrstr[INET6_ADDRSTRLEN];
+
+            inet_ntop(AF_INET6, sock_dns_server.addr.ipv6, addrstr,
+                      sizeof(addrstr));
+            printf("DNS server: [%s%%%d]:%u\n", addrstr, sock_dns_server.netif,
+                   sock_dns_server.port);
+        }
+        else {
+            puts("DNS server: -");
+        }
+    }
+    else {
+        _usage(argv[0]);
+    }
+    return res;
+}
+
+static int _dns(int argc, char **argv)
+{
+    if ((argc > 1) && (strcmp(argv[1], "server") == 0)) {
+        return _dns_server(argc, argv);
+    }
+    else {
+        _usage(argv[0]);
+        return 1;
+    }
+}
+
+int main(void)
+{
+    /* start shell */
+    shell_run(_shell_commands, _shell_buffer, sizeof(_shell_buffer));
+    return 0;
+}

tests/gnrc_ipv6_nib_dns/tests/01-run.py

@@ -0,0 +1,81 @@
+#!/usr/bin/env python3
+
+# Copyright (C) 2018 Freie Universität Berlin
+#
+# This file is subject to the terms and conditions of the GNU Lesser
+# General Public License v2.1. See the file LICENSE in the top level
+# directory for more details.
+
+import os
+import re
+import sys
+import subprocess
+
+from scapy.all import Ether, IPv6, ICMPv6ND_RA, ICMPv6NDOptRDNSS, sendp
+from testrunner import run
+
+
+def check_and_search_output(cmd, pattern, res_group, *args, **kwargs):
+    output = subprocess.check_output(cmd, *args, **kwargs).decode("utf-8")
+    for line in output.splitlines():
+        m = re.search(pattern, line)
+        if m is not None:
+            return m.group(res_group)
+    return None
+
+
+def get_bridge(tap):
+    res = check_and_search_output(
+            ["bridge", "link"],
+            r"{}.+master\s+(?P<master>[^\s]+)".format(tap),
+            "master"
+        )
+    return tap if res is None else res
+
+
+def get_host_lladdr(tap):
+    res = check_and_search_output(
+            ["ip", "addr", "show", "dev", tap, "scope", "link"],
+            r"inet6\s+(?P<lladdr>[0-9A-Fa-f:]+)/\d+",
+            "lladdr"
+        )
+    if res is None:
+        raise AssertionError(
+                "Can't find host link-local address on interface {}".format(tap)
+            )
+    else:
+        return res
+
+
+def dns_server(child):
+    child.sendline("dns server")
+    res = child.expect([r"DNS server: -",
+                        r"DNS server: \[([0-9a-f:]+)%\d+\]:(\d+)"])
+    if res > 0:
+        return child.match.group(1), int(child.match.group(2))
+    else:
+        return None
+
+
+DNS_ADDR = "2001:db8:affe::dead:beef"
+DNS_PORT = 53
+
+
+def testfunc(child):
+    tap = get_bridge(os.environ["TAP"])
+    lladdr_src = get_host_lladdr(tap)
+    child.sendline("ifconfig")
+    child.expect(r"HWaddr: (?P<hwaddr>[A-Fa-f:0-9]+)\s")
+    hwaddr_dst = child.match.group("hwaddr").lower()
+    child.expect(r"(?P<lladdr>fe80::[A-Fa-f:0-9]+)\s")
+    lladdr_dst = child.match.group("lladdr").lower()
+
+    assert dns_server(child) is None
+    sendp(Ether(dst=hwaddr_dst) / IPv6(dst=lladdr_dst, src=lladdr_src) /
+          ICMPv6ND_RA() / ICMPv6NDOptRDNSS(dns=[DNS_ADDR]),
+          iface=tap)
+    assert dns_server(child) == (DNS_ADDR, DNS_PORT)
+
+
+if __name__ == "__main__":
+    sys.exit(run(testfunc, timeout=1, echo=True))