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Building my own network stack

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Re: Building my own network stack

#81

Post by diath »

intrasight wrote: post #11

My first job was at Westinghouse instrumenting a nuclear power plant. Our entire hardware-software package was a freebie given to the customer as part of a $200 million refueling contract (and that's in 1988 dollars). We, a team of 10, created a bespoke application stack which was effectively a web browser. The client machines were Sun 3 workstations. The server was some industrial mini computer that didn't have a TC…

...what kind of credentials did you have to become a hw/sw engineer at a nuclear power plant as your first job?

Re: Building my own network stack

#82

Post by intrasight »

diath wrote: post #81
intrasight wrote: post #11

My first job was at Westinghouse instrumenting a nuclear power plant. Our entire hardware-software package was a freebie given to the customer as part of a $200 million refueling contract (and that's in 1988 dollars). We, a team of 10, created a bespoke application stack which was effectively a web browser. The client machines were Sun 3 workstations. The server was some industrial mini computer that didn't have a TC…

...what kind of credentials did you have to become a hw/sw engineer at a nuclear power plant as your first job?

Graduated and figured I should get a job. Honestly wasn't enthusiastic about the idea. Saw an ad in the paper. It may have mentioned C programming. I went and interviewed with two senior engineers. All they asked was do I know how to do TCP/IP. I said that I did and was working the next week. Honestly the coolest job I've had in my career. Colleagues were all engineers - mostly nuclear.

Re: Building my own network stack

#83

Post by intrasight »

p_l wrote: post #78
intrasight wrote: post #60

Earlier quoted context omitted.

The plant computer wasn't a DCS. I think it was a DEC. It gathered data from the control systems and instrumentation and had a bespoke in memory realtime-ish database. That database was then partially replicated down to the Sun workstations (code the 23 year old me wrote). Then the browser consumed that via a unix shared memory interface.

Was it perhaps DEC Baseway[1] system? It would arguably qualify as a form of DCS, with central VAX servers and running high level software, PDP-11 "shop floor" computers, which in turn talked with PLCs and related devices. And additionally, TCP/IP was an optional layered product - either DEC's own UCX (Ultrix Communication eXtensions) or 3rd party [1] https://bitsavers.org/pdf/dec/vax/vms/baseway/

I guess they didn't buy the optional network software.

I remember working with this engineer writing in the lower level TCPIP stack on the deck - maybe in Fortran? Anyway, he didn't understand why he wasn't getting all the data transmitted and while I was no expert in TCP/IP, I was already familiar with packets and maximum segment size (MSS). I remember being impressed that he banged out a network stack in a couple weeks.

Re: Building my own network stack

#84

Post by diath »

intrasight wrote: post #82
diath wrote: post #81

Earlier quoted context omitted.

...what kind of credentials did you have to become a hw/sw engineer at a nuclear power plant as your first job?

Graduated and figured I should get a job. Honestly wasn't enthusiastic about the idea. Saw an ad in the paper. It may have mentioned C programming. I went and interviewed with two senior engineers. All they asked was do I know how to do TCP/IP. I said that I did and was working the next week. Honestly the coolest job I've had in my career. Colleagues were all engineers - mostly nuclear.

Huh. Boomers really did live their lives on tutorial mode.

Re: Building my own network stack

#85

Post by defrost »

diath wrote: post #84
intrasight wrote: post #82

Earlier quoted context omitted.

Graduated and figured I should get a job. Honestly wasn't enthusiastic about the idea. Saw an ad in the paper. It may have mentioned C programming. I went and interviewed with two senior engineers. All they asked was do I know how to do TCP/IP. I said that I did and was working the next week. Honestly the coolest job I've had in my career. Colleagues were all engineers - mostly nuclear.

Huh. Boomers really did live their lives on tutorial mode.

Two decades before stack exchange and writing their own tools, yep.

Re: Building my own network stack

#86

Post by dilyevsky »

znnajdla wrote: post #57

The real nightmare scenario is not just finding a vulnerability in the Linux network stack but finding vulnerabilities at the protocol level in TCP/IP itself or HTTP. That’s a problem that cannot be fixed. Has there ever been a precedent for this in computing?

Yes, lots. Early spdy was vulnerable to CRIME attacks and so was TLS1.0 (and to bunch of other attacks). Kaminsky DNS cache poisoning is another one that comes to mind

Re: Building my own network stack

#87

Post by dilyevsky »

hn_submit wrote: post #41

This is just an opinion and not a very sensible one at that. The Linux TCP/IP stack is one of the most scrutinized network stacks in the world and more than likely free of bugs that coud lead to a server takeover.

Are you aware of the syzkaller and how many bugs it still finds including in networking stack?

Re: Building my own network stack

#88

Post by contingencies »

znnajdla wrote: post #57

The real nightmare scenario is not just finding a vulnerability in the Linux network stack but finding vulnerabilities at the protocol level in TCP/IP itself or HTTP. That’s a problem that cannot be fixed. Has there ever been a precedent for this in computing?

Many: OS detection (ICMP, IGMP, ARP, TCP, etc.), topology disclosure (ICMP), DoS (many early protocols did not perceive resource exhaustion in their threat model; a prominent example being SYN floods / TCP half-open), etc.

Re: Building my own network stack

#89

Post by p_l »

intrasight wrote: post #83
p_l wrote: post #78

Earlier quoted context omitted.

Was it perhaps DEC Baseway[1] system? It would arguably qualify as a form of DCS, with central VAX servers and running high level software, PDP-11 "shop floor" computers, which in turn talked with PLCs and related devices. And additionally, TCP/IP was an optional layered product - either DEC's own UCX (Ultrix Communication eXtensions) or 3rd party [1] https://bitsavers.org/pdf/dec/vax/vms/baseway/

I guess they didn't buy the optional network software. I remember working with this engineer writing in the lower level TCPIP stack on the deck - maybe in Fortran? Anyway, he didn't understand why he wasn't getting all the data transmitted and while I was no expert in TCP/IP, I was already familiar with packets and maximum segment size (MSS). I remember being impressed that he banged out a network stack in a couple w…

Baseway, and various other industrial control systems that also ran on VMS and related, tended to either use DEC-suggested (DECnet) protocols or implemented custom Ethernet-layer ones
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