11 ms·

SatCat5: FPGA gateware that implements a low-power, mixed-media Ethernet switch

165 points by sohkamyung 4y ago

malwrar 4y ago
I see no mention of security—If you’re exposing raw serial busses via ethernet, one would expect some manner of security controls, no?
- dogleash 4y ago
  All interfaces still talk Ethernet.
- jdsnape 4y ago
  I think it depends on the application. It's very unlikely someone will MITM the connection between components on a set of circuit boards in a satellite (the use-case they designed this for)
  - moremetadata 4y ago
    > SatCat5 also includes software libraries targeting both baremetal and POSIX systems for: So with the windows linux subsystem, it might just about run anywhere which could then introduce its own security situation. It will be interesting to see if the UAC prompt overrides I've seen when using Kali Linux and wireshark as a VMware guest on Win10, will also occur with this code. So the UAC prompt override's is where the Vmware guest network for Kali linux is put into promiscuous mode in order to capture all packets. Every windows reboot switches off the promiscuous mode and someone on here suggested its Vmware doing this not windows. Maybe this is the code/tool to see if it is windows or vmware overriding UAC protected settings or not.
  - ooterness 4y ago
    This exactly. The radio has the encryption; the LAN doesn't really need it. If you send a robot to wiretap the satellite then we're in trouble, but that's true regardless.
f_devd 4y ago
Interesting that it's both patented and under LGPLv3/GPLv3 (unclear which applies), seems like a way to avoid non-FOSS/proprietary implementations although I would think releasing it as regular GPLv3 would already serve as prior art under patent law, IANAL but would love to know.
- pclmulqdq 4y ago
  OSH licenses for FPGA code are a total mess. I am working on some hardware that I plan to open source very soon, but figuring out what license to use is extremely difficult. My options seem to be: * Start with CC-BY-NC that pretty clearly disallows commercial use in any way and punt on the question (or allow commercial users to pay a nominal fee for a commercial license) * GPL or LGPL - both of which are unclear how they apply in the case of ASIC and FPGA designs, particularly when you consider weird corner cases like partial reconfiguration (FPGA and ASIC tools allow you to sequester the open source block in its own "compilation unit" and compiling that unit separately from the main system, only connecting the wires at the last steps) * CERN OHLv2 license of some kind, which seems to give up its copyleft provisions on things that don't involve giving stuff to a customer * MIT/BSD A lot of folks in hardware are not particularly interested in going for the MIT/BSD route because of the commercial nature of IP cores. It essentially allows a random firm to repackage your IP and sell it as their own (usually for a shit load of money - hardware licenses are often 5-6 figures).
  - sitkack 4y ago
    You could look at MPL? https://www.mozilla.org/en-US/MPL/ https://www.mozilla.org/en-US/MPL/ I agree that hardware should have stronger copyleft requirements than code. MIT/BSD has a place where you have a consortium or an org encouraging the ecosystem to maintain compatibility. The gain is that the ecosystem is compatible with a spec, so the whole is more important than each individual entity.
    - pclmulqdq 4y ago
      I just read the MPL, and if you look at the CERN license, you can see some of the problems with licenses like GPL and MPL. In the software-oriented licenses, the lawyers who wrote them are very diligent to define things very clearly in software-specific terms, and then stop before defining those terms. It lets them keep the contract shorter and allow those definitions to change over time. For the GPL, this means taking the definition of "linking" for granted, and in the MPL, the definition of "larger work" pretty clearly seems to apply to only software: A "Larger Work" is a work that "...combines Covered Software with other material, in a separate file or files, that is not Covered Software." In software land, this is fine because you distribute software in the form of files, but if you are distributing the Covered software as a piece of silicon, it's unclear whether that is a "larger work" or not, because the other material is not in a separate file at the point of distribution. Here's the CERN "strongly reciprocal" license for reference, showing the difference between the software- and hardware-specific language: https://spdx.org/licenses/CERN-OHL-S-2.0.html https://spdx.org/licenses/CERN-OHL-S-2.0.html The CERN license, by the way, has the opposite problem for FPGA code - it defines things in terms that really apply to physical stuff.
seiferteric 4y ago
Wow this looks really cool and useful! I had a thought though, if the concept here is to create a local LAN for devices on a isolated system (satellite) to send data to each other, I wonder if there is some other model than a network that might be better. I am thinking like a shared memory store with transactional operations support, key/value and pub/sub notifications etc. Sort of like a hardware version of redis? Seems like dealing with network stuff is just necessary overhead.
- dogleash 4y ago
  Models other than networking already exist for the embedded space (some sorta analogous to what you propose, but not exactly thought about in those terms). They're the more common option than going all the way to a communication protocol as complex as ethernet. But you eventually have to bridge between that and typical IP networking. It's usually the responsibility of the designer to bring their own hardware for the transition between (e.g.) SPI and twisted pair Ethernet. That's why this project to put it in the switch is novel.
- sitkack 4y ago
  As an embodiment of hardware abstraction, the present invention relates to a key value interface in an Ethernet switch. The invention provides a Redis interface on the switch, enabling the interfacing with I2C devices to be akin to a read operation from a key/value store over the Redis protocol. The invention contemplates the publication of RISC-V or Wasm code to a key/value endpoint, followed by awaiting a response on a value. The present invention constitutes prior art in the patent categories of network switches, key-value stores, and hardware abstraction. patent classification codes: H04L, G06F 17/30, G06F 15/76, G06F 9/44 and G06F 9/455 Seemed like something someone would make a BS patent for, so I had ChatGPT spiffy it up.
bsder 4y ago
While I am always down with Ethernet All The Things(tm), this seems like an odd duck. I'm thinking that they wanted to monetize this but 10Base-T1L and 10Base-T1S sidelined them. SPI Ethernet chips have existed for quite a while. Existing COTS Ethernet switch chips are going to be far more robust and quite a bit smaller. And, now that you can actually buy 10Base-T1L and 10Base-T1S transceivers--you can get even lower power by reducing the signalling levels (or maybe not for space applications). T1L gets you solid industrial point-to-point robustness, and T1S finally gets you multi-drop on single pair again (And the angels sang "Hallelujah!" for networking like it's 1988). Both of which can have genuine transformer or transformerless galvanic isolation. All this for far cheaper, far less complexity and WAY less power than that FPGA. I guess the main advantage is UART interface Ethernet? A lot of cellular modem-like things have this really bastardized networking over UART that does have the advantage that it seems to be a "standardized" AT command set, so it's possible that this is important in satellite stuff which tends to piggyback on other industries as much as possible due to low volume.
- jhallenworld 4y ago
  Ethernet over UART: you mean PPP? (RFC 1661)
  - convolvatron 4y ago
    ppp doesn't use ethernet framing
- ooterness 4y ago
  Lead developer here. The intent from the start was to make an open-source design for the explicit purpose of encouraging adoption. The cubesat and smallsat industry as a whole could really use more standardization. In short: Writing a white-paper saying "plz use Ethernet in your cubesat" is one thing. Writing one that says "plz use Ethernet, we're using it for all of our new cubesats, and by the way here's the source code for the Ethernet switch" is quite another. For us, the main advantage is having a mixed-media switch. The Slingshot-1 cubesat launched July 2022 literally has UARTs and gigabit Ethernet (SGMII) on the same LAN.
leoedin 4y ago
The interfaces with devices over SPI/I2C etc is interesting. There's actually some other interesting developments in this area - 10Base-T1S and 10Base-T1L are recent standards that are designed to allow ethernet packet communication over much more lightweight multi-drop networks - basically allowing a small network of interconnected devices to talk ethernet to each other (and the outside world, via a bridge) without the requirement for bulky and expensive traditional ethernet transformers. https://www.microchip.com/en-us/solutions/ethernet-technology/single-pair-ethernet/10base-t1s https://www.microchip.com/en-us/solutions/ethernet-technolog... I don't think there's wide silicon support yet - but the prospect of a small network of sensors which communicate over ethernet, which can be effortlessly bridged to a standard network is quite nice.
- amluto 4y ago
  Not just sensors — entire devices and ecosystems of devices could use this, internally and for expandability. Anything that currently uses an RS-485-based protocol or even CAN could potentially switch.
  - ilyt 4y ago
    But..why ? Surely just having some IP-over-CAN and using all of the existing CAN-equipped micros would be easier/cheaper?
    - ooterness 4y ago
      IP over CAN is fine, but the useful throughput is limited. Overhead is very high because the frames are so short--64 useful bits in every 108-bit frame--so you end up repeating the headers many times. That limits effective throughput to about 600 kbps on a 1 Mbps shared bus. (And the nature of the shared bus means that's a single throughput budget for all attached devices.)
    - danielheath 4y ago
      Being able to sell a sensor that plugs into the existing network?
deleted 4y ago
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teleforce 4y ago
Thanks for sharing, just learnt from the article and the following link the meaning of gateware: https://www.gateware.org/definition-of-gateware https://www.gateware.org/definition-of-gateware
myself248 4y ago
This is really intriguing. I was recently pondering something related: 10/100 ethernet only uses two pairs, one in each direction. Of course the jack has four pairs, and the cable has four pairs and gigabit uses all four. But, if you're only using 10/100, it's trivial to split the jack on either end of a run, and carry two "ports" worth over a single cat5 cable. However, this requires a second splitter at the switch end, like so: https://lib.store.yahoo.net/lib/cablesonline/NETWORK13.JPG https://lib.store.yahoo.net/lib/cablesonline/NETWORK13.JPG Would it be possible for a suitably-bastardized GigE PHY to drive the four pairs as two independent "ports" of 10/100, assuming such a splitter was just on the far end, but the cable on the near end was plugged directly into the switch? Don't ask about practical applications, I really have none in mind. It just struck me as a perverted and wrong thing to do, therefore it must be done. (And on that note, since GigE really runs the four pairs as four nearly-independent bidirectional channels and then merges their capacity afterward.... could you get four 250Mbps "ports" out of such a thing? By routing all four pairs to four separate devices, each of which is also running this bonkers implementation? Essentially reinventing single-pair ethernet (yet again yet again yet again yet again) using all stock PHYs. This would require cooperating devices on both ends of the link, but the prior idea could be used with stock 10/100 devices.)
- xxpor 4y ago
  that's hilarious. it's essentially a physical vlan. it could be of use for anything that doesn't support vlans directly, and it'd be a lot cheaper than running a switch to do the tagging/untagging.
  - myself248 4y ago
    I've done exactly that, when I couldn't be arsed to figure out QinQ on a wrt54g which already uses VLAN tagging internally between the SOC and the switch ASIC. Just used two physical ports and a splitting scheme just like the above. The trick would be doing it with _one_ physical port on a suitably malleable GigE-equipped device.
- zamadatix 4y ago
  A lot of modern Ethernet speeds are the result of what you mention at the end. Doing it with a gigabit port was never standardized to my knowledge, it only really got popular after 10G and later hit the scene, but there shouldn't be anything preventing a custom implementation.
jhallenworld 4y ago
Looking at their patent: how is this different from an IOT gateway? Or a router that supports SLIP, ATM, PPP, etc.? Whatever..

165 points by sohkamyung 4y ago

I see no mention of security—If you’re exposing raw serial busses via ethernet, one would expect some manner of security controls, no?

dogleash 4y ago
All interfaces still talk Ethernet.
jdsnape 4y ago
I think it depends on the application. It's very unlikely someone will MITM the connection between components on a set of circuit boards in a satellite (the use-case they designed this for)
- moremetadata 4y ago
  > SatCat5 also includes software libraries targeting both baremetal and POSIX systems for: So with the windows linux subsystem, it might just about run anywhere which could then introduce its own security situation. It will be interesting to see if the UAC prompt overrides I've seen when using Kali Linux and wireshark as a VMware guest on Win10, will also occur with this code. So the UAC prompt override's is where the Vmware guest network for Kali linux is put into promiscuous mode in order to capture all packets. Every windows reboot switches off the promiscuous mode and someone on here suggested its Vmware doing this not windows. Maybe this is the code/tool to see if it is windows or vmware overriding UAC protected settings or not.
- ooterness 4y ago
  This exactly. The radio has the encryption; the LAN doesn't really need it. If you send a robot to wiretap the satellite then we're in trouble, but that's true regardless.

f_devd 4y ago

Interesting that it's both patented and under LGPLv3/GPLv3 (unclear which applies), seems like a way to avoid non-FOSS/proprietary implementations although I would think releasing it as regular GPLv3 would already serve as prior art under patent law, IANAL but would love to know.

pclmulqdq 4y ago
OSH licenses for FPGA code are a total mess. I am working on some hardware that I plan to open source very soon, but figuring out what license to use is extremely difficult. My options seem to be: * Start with CC-BY-NC that pretty clearly disallows commercial use in any way and punt on the question (or allow commercial users to pay a nominal fee for a commercial license) * GPL or LGPL - both of which are unclear how they apply in the case of ASIC and FPGA designs, particularly when you consider weird corner cases like partial reconfiguration (FPGA and ASIC tools allow you to sequester the open source block in its own "compilation unit" and compiling that unit separately from the main system, only connecting the wires at the last steps) * CERN OHLv2 license of some kind, which seems to give up its copyleft provisions on things that don't involve giving stuff to a customer * MIT/BSD A lot of folks in hardware are not particularly interested in going for the MIT/BSD route because of the commercial nature of IP cores. It essentially allows a random firm to repackage your IP and sell it as their own (usually for a shit load of money - hardware licenses are often 5-6 figures).
- sitkack 4y ago
  You could look at MPL? https://www.mozilla.org/en-US/MPL/ https://www.mozilla.org/en-US/MPL/ I agree that hardware should have stronger copyleft requirements than code. MIT/BSD has a place where you have a consortium or an org encouraging the ecosystem to maintain compatibility. The gain is that the ecosystem is compatible with a spec, so the whole is more important than each individual entity.
  - pclmulqdq 4y ago
    I just read the MPL, and if you look at the CERN license, you can see some of the problems with licenses like GPL and MPL. In the software-oriented licenses, the lawyers who wrote them are very diligent to define things very clearly in software-specific terms, and then stop before defining those terms. It lets them keep the contract shorter and allow those definitions to change over time. For the GPL, this means taking the definition of "linking" for granted, and in the MPL, the definition of "larger work" pretty clearly seems to apply to only software: A "Larger Work" is a work that "...combines Covered Software with other material, in a separate file or files, that is not Covered Software." In software land, this is fine because you distribute software in the form of files, but if you are distributing the Covered software as a piece of silicon, it's unclear whether that is a "larger work" or not, because the other material is not in a separate file at the point of distribution. Here's the CERN "strongly reciprocal" license for reference, showing the difference between the software- and hardware-specific language: https://spdx.org/licenses/CERN-OHL-S-2.0.html https://spdx.org/licenses/CERN-OHL-S-2.0.html The CERN license, by the way, has the opposite problem for FPGA code - it defines things in terms that really apply to physical stuff.

seiferteric 4y ago

Wow this looks really cool and useful! I had a thought though, if the concept here is to create a local LAN for devices on a isolated system (satellite) to send data to each other, I wonder if there is some other model than a network that might be better. I am thinking like a shared memory store with transactional operations support, key/value and pub/sub notifications etc. Sort of like a hardware version of redis? Seems like dealing with network stuff is just necessary overhead.

dogleash 4y ago
Models other than networking already exist for the embedded space (some sorta analogous to what you propose, but not exactly thought about in those terms). They're the more common option than going all the way to a communication protocol as complex as ethernet. But you eventually have to bridge between that and typical IP networking. It's usually the responsibility of the designer to bring their own hardware for the transition between (e.g.) SPI and twisted pair Ethernet. That's why this project to put it in the switch is novel.
sitkack 4y ago
As an embodiment of hardware abstraction, the present invention relates to a key value interface in an Ethernet switch. The invention provides a Redis interface on the switch, enabling the interfacing with I2C devices to be akin to a read operation from a key/value store over the Redis protocol. The invention contemplates the publication of RISC-V or Wasm code to a key/value endpoint, followed by awaiting a response on a value. The present invention constitutes prior art in the patent categories of network switches, key-value stores, and hardware abstraction. patent classification codes: H04L, G06F 17/30, G06F 15/76, G06F 9/44 and G06F 9/455 Seemed like something someone would make a BS patent for, so I had ChatGPT spiffy it up.

bsder 4y ago

While I am always down with Ethernet All The Things(tm), this seems like an odd duck. I'm thinking that they wanted to monetize this but 10Base-T1L and 10Base-T1S sidelined them. SPI Ethernet chips have existed for quite a while. Existing COTS Ethernet switch chips are going to be far more robust and quite a bit smaller. And, now that you can actually buy 10Base-T1L and 10Base-T1S transceivers--you can get even lower power by reducing the signalling levels (or maybe not for space applications). T1L gets you solid industrial point-to-point robustness, and T1S finally gets you multi-drop on single pair again (And the angels sang "Hallelujah!" for networking like it's 1988). Both of which can have genuine transformer or transformerless galvanic isolation. All this for far cheaper, far less complexity and WAY less power than that FPGA. I guess the main advantage is UART interface Ethernet? A lot of cellular modem-like things have this really bastardized networking over UART that does have the advantage that it seems to be a "standardized" AT command set, so it's possible that this is important in satellite stuff which tends to piggyback on other industries as much as possible due to low volume.

jhallenworld 4y ago
Ethernet over UART: you mean PPP? (RFC 1661)
- convolvatron 4y ago
  ppp doesn't use ethernet framing
ooterness 4y ago
Lead developer here. The intent from the start was to make an open-source design for the explicit purpose of encouraging adoption. The cubesat and smallsat industry as a whole could really use more standardization. In short: Writing a white-paper saying "plz use Ethernet in your cubesat" is one thing. Writing one that says "plz use Ethernet, we're using it for all of our new cubesats, and by the way here's the source code for the Ethernet switch" is quite another. For us, the main advantage is having a mixed-media switch. The Slingshot-1 cubesat launched July 2022 literally has UARTs and gigabit Ethernet (SGMII) on the same LAN.

leoedin 4y ago

The interfaces with devices over SPI/I2C etc is interesting. There's actually some other interesting developments in this area - 10Base-T1S and 10Base-T1L are recent standards that are designed to allow ethernet packet communication over much more lightweight multi-drop networks - basically allowing a small network of interconnected devices to talk ethernet to each other (and the outside world, via a bridge) without the requirement for bulky and expensive traditional ethernet transformers. https://www.microchip.com/en-us/solutions/ethernet-technology/single-pair-ethernet/10base-t1s https://www.microchip.com/en-us/solutions/ethernet-technolog... I don't think there's wide silicon support yet - but the prospect of a small network of sensors which communicate over ethernet, which can be effortlessly bridged to a standard network is quite nice.

amluto 4y ago
Not just sensors — entire devices and ecosystems of devices could use this, internally and for expandability. Anything that currently uses an RS-485-based protocol or even CAN could potentially switch.
- ilyt 4y ago
  But..why ? Surely just having some IP-over-CAN and using all of the existing CAN-equipped micros would be easier/cheaper?
  - ooterness 4y ago
    IP over CAN is fine, but the useful throughput is limited. Overhead is very high because the frames are so short--64 useful bits in every 108-bit frame--so you end up repeating the headers many times. That limits effective throughput to about 600 kbps on a 1 Mbps shared bus. (And the nature of the shared bus means that's a single throughput budget for all attached devices.)
  - danielheath 4y ago
    Being able to sell a sensor that plugs into the existing network?

deleted 4y ago

[deleted]

deleted 4y ago
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- deleted 4y ago
  [deleted]

teleforce 4y ago

Thanks for sharing, just learnt from the article and the following link the meaning of gateware: https://www.gateware.org/definition-of-gateware https://www.gateware.org/definition-of-gateware

myself248 4y ago

This is really intriguing. I was recently pondering something related: 10/100 ethernet only uses two pairs, one in each direction. Of course the jack has four pairs, and the cable has four pairs and gigabit uses all four. But, if you're only using 10/100, it's trivial to split the jack on either end of a run, and carry two "ports" worth over a single cat5 cable. However, this requires a second splitter at the switch end, like so: https://lib.store.yahoo.net/lib/cablesonline/NETWORK13.JPG https://lib.store.yahoo.net/lib/cablesonline/NETWORK13.JPG Would it be possible for a suitably-bastardized GigE PHY to drive the four pairs as two independent "ports" of 10/100, assuming such a splitter was just on the far end, but the cable on the near end was plugged directly into the switch? Don't ask about practical applications, I really have none in mind. It just struck me as a perverted and wrong thing to do, therefore it must be done. (And on that note, since GigE really runs the four pairs as four nearly-independent bidirectional channels and then merges their capacity afterward.... could you get four 250Mbps "ports" out of such a thing? By routing all four pairs to four separate devices, each of which is also running this bonkers implementation? Essentially reinventing single-pair ethernet (yet again yet again yet again yet again) using all stock PHYs. This would require cooperating devices on both ends of the link, but the prior idea could be used with stock 10/100 devices.)

xxpor 4y ago
that's hilarious. it's essentially a physical vlan. it could be of use for anything that doesn't support vlans directly, and it'd be a lot cheaper than running a switch to do the tagging/untagging.
- myself248 4y ago
  I've done exactly that, when I couldn't be arsed to figure out QinQ on a wrt54g which already uses VLAN tagging internally between the SOC and the switch ASIC. Just used two physical ports and a splitting scheme just like the above. The trick would be doing it with _one_ physical port on a suitably malleable GigE-equipped device.
zamadatix 4y ago
A lot of modern Ethernet speeds are the result of what you mention at the end. Doing it with a gigabit port was never standardized to my knowledge, it only really got popular after 10G and later hit the scene, but there shouldn't be anything preventing a custom implementation.

jhallenworld 4y ago

Looking at their patent: how is this different from an IOT gateway? Or a router that supports SLIP, ATM, PPP, etc.? Whatever..