mirror of
https://github.com/kernelkit/infix.git
synced 2026-07-29 12:13:01 +02:00
Joachim Wiberg
c6fae88268
mDNS-SD was added in Windows 10 Creators Update[1] (build 1703), relased April 11, 2017. This makes SSDP no longer critical for finding an Infix device in Windows, both ping infix-01-02-03.local and using Chrome work. Since all major operating systems now support mDNS-SD[2] we've decided to standardize on that and LLDP for Infix and its derivatives. Other reasons for dropping it include, but is not limited to: lack of IPv6 in the implementation we use, and potential security implications[3]. [1]: https://en.wikipedia.org/wiki/Windows_10,_version_1703 [2]: https://techcommunity.microsoft.com/t5/networking-blog/mdns-in-the-enterprise/ba-p/3275777 [3]: https://blog.cloudflare.com/ssdp-100gbps/ Signed-off-by: Joachim Wiberg <troglobit@gmail.com>
177 lines
6.7 KiB
Markdown
177 lines
6.7 KiB
Markdown
Discover Infix Units
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====================
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```
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.----. Ethernet .-------.
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| PC +---------------------+ Infix |
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'----' if1 eth0 '-------'
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```
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Figure 1: PC directly connected over Ethernet to Infix unit (here eth0).
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When you wish to discover the IP address of an Infix switch, the simplest
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way is probably to *ping the IPv6 all-hosts* address (ff02::1) over a
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directly connected Ethernet cable. The unit's link-local IPv6 address is
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seen in the response.
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In the example below, the PC is connected to Infix via interface *tap0*
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(*tap0* is *if1* in Figure 1) and Infix responds with address
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*fe80::ff:fe00:0*.
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```
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linux-pc:# ping -6 -L -c 3 ff02::1%tap0
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PING ff02::1%tap0(ff02::1%tap0) 56 data bytes
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64 bytes from fe80::ff:fe00:0%tap0: icmp_seq=1 ttl=64 time=0.558 ms
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64 bytes from fe80::ff:fe00:0%tap0: icmp_seq=2 ttl=64 time=0.419 ms
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64 bytes from fe80::ff:fe00:0%tap0: icmp_seq=3 ttl=64 time=0.389 ms
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--- ff02::1%tap0 ping statistics ---
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3 packets transmitted, 3 received, 0% packet loss, time 2043ms
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rtt min/avg/max/mdev = 0.389/0.455/0.558/0.073 ms
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linux-pc:#
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```
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The PC could connect then connect to Infix, e.g., using SSH.
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```
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linux-pc:# ssh admin@fe80::ff:fe00:0%tap0
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admin@fe80::ff:fe00:0%tap0's password: admin
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admin@infix-00-00-00:~$
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```
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## Discovery mechanisms available in Infix
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Infix advertises its presence via the [mDNS](#mdns) and [LLDP](#lldp)
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discovery protocols.
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### LLDP
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Infix supports LLDP (IEEE 802.1AB). For a unit with factory default
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settings, the PC can readout the link-local IPv6 address from the
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Management Address TLV using *tcpdump* or other sniffing tools[^1].
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```
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linux-pc:# tcpdump -i tap0 -Qin -v ether proto 0x88cc
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tcpdump: listening on tap0, link-type EN10MB (Ethernet), snapshot length 262144 bytes
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15:51:52.061071 LLDP, length 193
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Chassis ID TLV (1), length 7
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Subtype MAC address (4): 02:00:00:00:00:00 (oui Unknown)
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Port ID TLV (2), length 7
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Subtype MAC address (3): 02:00:00:00:00:00 (oui Unknown)
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Time to Live TLV (3), length 2: TTL 120s
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System Name TLV (5), length 14: infix-00-00-00
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System Description TLV (6), length 91
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Infix by KernelKit Linux 5.19.17 #1 SMP PREEMPT_DYNAMIC Wed Jun 7 08:47:23 CEST 2023 x86_64
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System Capabilities TLV (7), length 4
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System Capabilities [Bridge, WLAN AP, Router, Station Only] (0x009c)
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Enabled Capabilities [Station Only] (0x0080)
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Management Address TLV (8), length 24
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Management Address length 17, AFI IPv6 (2): fe80::ff:fe00:0
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Interface Index Interface Numbering (2): 2
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Port Description TLV (4), length 4: eth0
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Organization specific TLV (127), length 9: OUI IEEE 802.3 Private (0x00120f)
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Link aggregation Subtype (3)
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aggregation status [supported], aggregation port ID 0
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Organization specific TLV (127), length 9: OUI IEEE 802.3 Private (0x00120f)
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MAC/PHY configuration/status Subtype (1)
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autonegotiation [none] (0x00)
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PMD autoneg capability [unknown] (0x8000)
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MAU type Unknown (0x0000)
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End TLV (0), length 0
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^C
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1 packet captured
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linux-pc:#
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```
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If the unit has an IPv4 address assigned, it is shown in an additional
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Management Address TLV.
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> **Note** The Management Addresses shown by LLDP are not
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> necessarily associated with the port transmitting the LLDP message.
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In the example below, the IPv4 address (10.0.1.1) happens to be
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assigned to *eth0*, while the IPv6 address (2001:db8::1) is not.
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```
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linux-pc:# sudo tcpdump -i tap0 -Qin -v ether proto 0x88cc
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tcpdump: listening on tap0, link-type EN10MB (Ethernet), snapshot length 262144 bytes
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15:46:07.908665 LLDP, length 207
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Chassis ID TLV (1), length 7
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Subtype MAC address (4): 02:00:00:00:00:00 (oui Unknown)
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Port ID TLV (2), length 7
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Subtype MAC address (3): 02:00:00:00:00:00 (oui Unknown)
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Time to Live TLV (3), length 2: TTL 120s
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System Name TLV (5), length 14: infix-00-00-00
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System Description TLV (6), length 91
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Infix by KernelKit Linux 5.19.17 #1 SMP PREEMPT_DYNAMIC Wed Jun 7 08:47:23 CEST 2023 x86_64
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System Capabilities TLV (7), length 4
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System Capabilities [Bridge, WLAN AP, Router, Station Only] (0x009c)
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Enabled Capabilities [Station Only] (0x0080)
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Management Address TLV (8), length 12
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Management Address length 5, AFI IPv4 (1): 10.0.1.1
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Interface Index Interface Numbering (2): 2
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Management Address TLV (8), length 24
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Management Address length 17, AFI IPv6 (2): 2001:db8::1
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Interface Index Interface Numbering (2): 3
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Port Description TLV (4), length 4: eth0
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Organization specific TLV (127), length 9: OUI IEEE 802.3 Private (0x00120f)
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Link aggregation Subtype (3)
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aggregation status [supported], aggregation port ID 0
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Organization specific TLV (127), length 9: OUI IEEE 802.3 Private (0x00120f)
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MAC/PHY configuration/status Subtype (1)
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autonegotiation [none] (0x00)
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PMD autoneg capability [unknown] (0x8000)
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MAU type Unknown (0x0000)
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End TLV (0), length 0
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^C
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1 packet captured
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2 packets received by filter
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0 packets dropped by kernel
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linux-pc:#
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```
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[^1]: [lldpd: implementation of IEEE 802.1ab
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(LLDP)](https://github.com/lldp/lldpd) includes *lldpcli*, which
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is handy to sniff and display LLDP packets.
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### mDNS
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DNS-SD/mDNS can be used to discover Infix units and services. Infix
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units present their IP addresses, services and hostname within the
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.local domain. This method has good client support in Apple and Linux
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systems. On Linux, tools such as *avahi-browse* or *mdns-scan*[^2] can
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be used to search for devices advertising their services via mDNS.
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```
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linux-pc:# avahi-browse -ar
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+ tap0 IPv6 infix-00-00-00 SFTP File Transfer local
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+ tap0 IPv4 infix-00-00-00 SFTP File Transfer local
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+ tap0 IPv6 infix-00-00-00 SSH Remote Terminal local
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+ tap0 IPv4 infix-00-00-00 SSH Remote Terminal local
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= tap0 IPv4 infix-00-00-00 SFTP File Transfer local
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hostname = [infix-00-00-00.local]
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address = [10.0.1.1]
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port = [22]
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txt = []
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= tap0 IPv4 infix-00-00-00 SSH Remote Terminal local
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hostname = [infix-00-00-00.local]
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address = [10.0.1.1]
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port = [22]
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txt = []
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= tap0 IPv6 infix-00-00-00 SFTP File Transfer local
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hostname = [infix-00-00-00.local]
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address = [fe80::ff:fe00:0]
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port = [22]
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txt = []
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= tap0 IPv6 infix-00-00-00 SSH Remote Terminal local
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hostname = [infix-00-00-00.local]
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address = [fe80::ff:fe00:0]
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port = [22]
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txt = []
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^C
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linux-pc:#
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```
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[^2]: [mdns-scan](http://0pointer.de/lennart/projects/mdns-scan/): a
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tool for scanning for mDNS/DNS-SD published services on the local
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network
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