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> My productivity in Rust has become very low compared to other languages such as Go or even C, that let me easily express what I want to do. As a C/C++ progra

> My productivity in Rust has become very low compared to other languages such as Go or even C, that let me easily express what I want to do. As a C/C++ programmer who has being following Rust from a distance for sometime, with an intention to learn it later, this is somewhat concerning to hear. I've been meaning to start learning it for some time, however, my current workload doesn't provide enough spare time to start absorbing it. In addition, it seems to be somewhat hard to find detailed information on how to do low-level things that would be very easy in C. Just as an example, one of our simulations relies on being able to craft raw UDP packets in order to "impersonate" remote basestations in our lab environment. While this is trivial to do in C or C++, I haven't been able to find a good reference on how to do that with Rust. The lack of accessible documentation means that I'm unlikely to consider writing some of these more security sensitive parts of our system in Rust, even though there may be net benefits to doing so.

burntsushi 7y ago
That's just one take, and I very much do not agree with it personally. My productivity has only gone up as the tooling and language have improved. One thing that I am working on figuring right now is the proliferation of dependencies. But that's a"nice" problem to have. > Just as an example, one of our simulations relies on being able to craft raw UDP packets in order to "impersonate" remote basestations in our lab environment. I would assume you would do it in Rust just like you would in C. Where's the hang up?
- nineteen999 7y ago
  > I would assume you would do it in Rust just like you would in C. Where's the hang up? Why assume? If you know it can be done, why wouldn't you provide a pointer to an example? I've done my Google searching and can't find one. There are endless examples of this for C online, I'm just stating that with a cursory search I couldn't find one for Rust. The hang up is clearly at my end, I'm currently time poor, so now is not a good time for me to be learning a new language where I can't find good examples for what I'd use it for. Admittedly I need to start at "Hello World" with Rust anyway before I get as far as crafting raw UDP packets. The point I'm getting at is if I didn't know how to program in either C or Rust, I'd pick C for this problem right now because there are clear examples. That's all.
  - burntsushi 7y ago
    If you don't know how to do it because you don't know Rust, then fine, that's reasonable. (Albeit a strange criticism to lodge from my perspective.) Otherwise, I would "assume" that you need to use libc bindings over ffi to use whatever udp APIs you would normally use from C. This is how Rust's standard library implements the higher level udp APIs for example: https://doc.rust-lang.org/std/net/struct.UdpSocket.html https://doc.rust-lang.org/std/net/struct.UdpSocket.html But I used a question mark also because this is not something I've done before, so I can't share an example. I wasn't being adversarial. Even my suggestion above could be wrong. That is, I don't understand the essential difficulty here. Perhaps someone else can chime in.
    - nineteen999 7y ago
      Sorry, not to be rude but in this case is sounds like you don't understand the problem domain. Perhaps I should have just said "UDP spoofing". There is a huge difference between creating a generic UDP endpoint like the code you have shown, and crafting a raw UDP socket, where the source IP address is "spoofed", and UDP checksums generated to ensure that the packet looks like a valid UDP packet so that the intermediate network infrastructure like routers, switches and firewalls will pass the forged packet rather than discarding it. The latter requires quite a bit of extra code. A good example is here: https://www.binarytides.com/raw-udp-sockets-c-linux/ https://www.binarytides.com/raw-udp-sockets-c-linux/ and last time I looked (month or so ago?) I could not find an equivalent example for Rust. It may be out there but I was unable to locate it. I'm not asking you to do my homework for me, just stating that learning what I need to know in Rust to do the above would take more time than I have available right now. That's not to say I won't figure it out in the future when I have more time. > If you don't know how to do it because you don't know Rust, then fine, that's reasonable. (Albeit a strange criticism to lodge from my perspective.) It's not a criticism of the language; what I'm asking may be very possible, I don't know yet. I just know that finding C examples is trivial, Rust examples not so much, so when I had a need for this kind of code recently, I turned to the language where I know it can be done and I could easily find examples.
      - 7y ago
arghnoname 7y ago
I am not a Rust expert, but I've written kernel modules in it so I've had to deal with interacting with the foreign function interface and didn't have the benefit of any of its standard library. The basic answer on this is you can specify that structures in rust have the same representation as a comparable C structure. If this isn't good enough for your use case (and it isn't when representing some wire format), then there are additional keywords to more precisely define the packing. Of course, it's also possible to just have a binary blob of the appropriate size and write the appropriate values at the appropriate offset inside of it. Generally I've been able to do whatever I need to do in Rust. I also wouldn't discount wrapping some C code at the very lowest layers. This isn't very different than using C code in a C++ project. Yes, it weakens type safety, but at the end of the day we have to get shit done, no? To the higher level point of whether or not it's worth learning rust: I don't know. How much time do you spend implementing and how much time do you spend fixing? Rust increases the former and decreases the latter.

burntsushi 7y ago

That's just one take, and I very much do not agree with it personally. My productivity has only gone up as the tooling and language have improved. One thing that I am working on figuring right now is the proliferation of dependencies. But that's a"nice" problem to have. > Just as an example, one of our simulations relies on being able to craft raw UDP packets in order to "impersonate" remote basestations in our lab environment. I would assume you would do it in Rust just like you would in C. Where's the hang up?

nineteen999 7y ago
> I would assume you would do it in Rust just like you would in C. Where's the hang up? Why assume? If you know it can be done, why wouldn't you provide a pointer to an example? I've done my Google searching and can't find one. There are endless examples of this for C online, I'm just stating that with a cursory search I couldn't find one for Rust. The hang up is clearly at my end, I'm currently time poor, so now is not a good time for me to be learning a new language where I can't find good examples for what I'd use it for. Admittedly I need to start at "Hello World" with Rust anyway before I get as far as crafting raw UDP packets. The point I'm getting at is if I didn't know how to program in either C or Rust, I'd pick C for this problem right now because there are clear examples. That's all.
- burntsushi 7y ago
  If you don't know how to do it because you don't know Rust, then fine, that's reasonable. (Albeit a strange criticism to lodge from my perspective.) Otherwise, I would "assume" that you need to use libc bindings over ffi to use whatever udp APIs you would normally use from C. This is how Rust's standard library implements the higher level udp APIs for example: https://doc.rust-lang.org/std/net/struct.UdpSocket.html https://doc.rust-lang.org/std/net/struct.UdpSocket.html But I used a question mark also because this is not something I've done before, so I can't share an example. I wasn't being adversarial. Even my suggestion above could be wrong. That is, I don't understand the essential difficulty here. Perhaps someone else can chime in.
  - nineteen999 7y ago
    Sorry, not to be rude but in this case is sounds like you don't understand the problem domain. Perhaps I should have just said "UDP spoofing". There is a huge difference between creating a generic UDP endpoint like the code you have shown, and crafting a raw UDP socket, where the source IP address is "spoofed", and UDP checksums generated to ensure that the packet looks like a valid UDP packet so that the intermediate network infrastructure like routers, switches and firewalls will pass the forged packet rather than discarding it. The latter requires quite a bit of extra code. A good example is here: https://www.binarytides.com/raw-udp-sockets-c-linux/ https://www.binarytides.com/raw-udp-sockets-c-linux/ and last time I looked (month or so ago?) I could not find an equivalent example for Rust. It may be out there but I was unable to locate it. I'm not asking you to do my homework for me, just stating that learning what I need to know in Rust to do the above would take more time than I have available right now. That's not to say I won't figure it out in the future when I have more time. > If you don't know how to do it because you don't know Rust, then fine, that's reasonable. (Albeit a strange criticism to lodge from my perspective.) It's not a criticism of the language; what I'm asking may be very possible, I don't know yet. I just know that finding C examples is trivial, Rust examples not so much, so when I had a need for this kind of code recently, I turned to the language where I know it can be done and I could easily find examples.
    - 7y ago

arghnoname 7y ago

I am not a Rust expert, but I've written kernel modules in it so I've had to deal with interacting with the foreign function interface and didn't have the benefit of any of its standard library. The basic answer on this is you can specify that structures in rust have the same representation as a comparable C structure. If this isn't good enough for your use case (and it isn't when representing some wire format), then there are additional keywords to more precisely define the packing. Of course, it's also possible to just have a binary blob of the appropriate size and write the appropriate values at the appropriate offset inside of it. Generally I've been able to do whatever I need to do in Rust. I also wouldn't discount wrapping some C code at the very lowest layers. This isn't very different than using C code in a C++ project. Yes, it weakens type safety, but at the end of the day we have to get shit done, no? To the higher level point of whether or not it's worth learning rust: I don't know. How much time do you spend implementing and how much time do you spend fixing? Rust increases the former and decreases the latter.