| DNS Client Application |
| ====================== |
| |
| The DNS resolver or DNS client application demonstrates how to use the |
| DNS resolver API. |
| |
| The DNS API allows to recover IPv4 and IPv6 addresses. |
| |
| |
| API Return Codes |
| ================ |
| |
| API return codes are documented in the API (see include/iot/dns_client.h). |
| |
| Macro | Value | Description |
| ------------------------------------------------------------------------ |
| O is always success |
| -EINVAL -22 if an invalid parameter was detected |
| -EIO -5 network error |
| -ENOMEM -12 memory error, perhaps related to network buffers |
| |
| |
| Requirements |
| ============ |
| |
| 'net_tools': |
| |
| https://wiki.zephyrproject.org/view/Networking-with-Qemu |
| |
| 'dnsmasq' application. The dnsmasq version used in this sample is: |
| |
| dnsmasq -v |
| Dnsmasq version 2.76 Copyright (c) 2000-2016 Simon Kelley |
| |
| |
| Building Instructions |
| ===================== |
| |
| Read src/config.h, change the IP addresses according to the LAN |
| environment. |
| |
| In a terminal window, type make pristine && make to build this sample. |
| |
| |
| Usage |
| ===== |
| |
| Run 'loop_socat.sh' and 'loop-slip-tap.sh' as indicated at: |
| |
| https://gerrit.zephyrproject.org/r/gitweb?p=net-tools.git;a=blob;f=README |
| |
| Set the IPv4 ip address: |
| |
| ip addr add 192.0.2.2/24 dev tap0 |
| |
| Open a terminal window and type: |
| |
| dnsmasq -i tap0 -p 5353 -d |
| |
| NOTE: some systems may require root privileges to run dnsmaq, use sudo or su. |
| |
| If dnsmasq fails to start with an error like this: |
| |
| dnsmasq: failed to create listening socket for port 5353: Address already in use |
| |
| open a terminal window and type: |
| |
| killall -s KILL dnsmasq |
| |
| For QEMU, type: |
| |
| make qemu |
| |
| |
| Sample Output (CONFIG_NET_IPV6=n, CONFIG_NET_IPV4=y) |
| ==================================================== |
| |
| To exit from QEMU enter: 'CTRL+a, x' |
| [QEMU] CPU: qemu32 |
| |
| ------------------------------------------- |
| [run_dns:127] name: not_a_real_domain_name |
| rc: -22 |
| |
| ------------------------------------------- |
| [run_dns:127] name: zephyrproject.org |
| [run_dns:151] 140.211.169.8 |
| |
| ------------------------------------------- |
| [run_dns:127] name: www.zephyrproject.org |
| [run_dns:151] 140.211.169.8 |
| |
| ------------------------------------------- |
| [run_dns:127] name: gerrit.zephyrproject.org |
| [run_dns:151] 199.19.213.246 |
| |
| ------------------------------------------- |
| [run_dns:127] name: jira.zephyrproject.org |
| [run_dns:151] 199.19.213.246 |
| |
| ------------------------------------------- |
| [run_dns:127] name: jenkins.zephyrproject.org |
| [run_dns:151] 199.19.213.246 |
| |
| ------------------------------------------- |
| [run_dns:127] name: linuxfoundation.org |
| rc: -5 |
| |
| ------------------------------------------- |
| [run_dns:127] name: www.linuxfoundation.org |
| [run_dns:151] 140.211.169.4 |
| |
| ------------------------------------------- |
| [run_dns:127] name: collabprojects.linuxfoundation.org |
| [run_dns:151] 140.211.169.4 |
| |
| ------------------------------------------- |
| [run_dns:127] name: events.linuxfoundation.org |
| [run_dns:151] 140.211.169.4 |
| |
| ------------------------------------------- |
| [run_dns:127] name: training.linuxfoundation.org |
| [run_dns:151] 140.211.169.4 |
| |
| Bye! |
| |
| Known Issues |
| ============ |
| |
| The above sample contains a rc: -22 (-EINVAL). This is the expected behavior |
| for that domain name. |
