Getting IPv6 extension header fields

[Hajar Hantouti]

Hello ,
I'am implementing a new Ipv6 extension header , attaching it to packets . at reception of these packets I want to access the new extension header fields.
till now I can retrieve the Extension header , but not able to access fields . I was inspired by Packet::Print function , but I get compilation errors using GetAttributeName and GetAttribute. Here is the Print code that I'm using:

 std::string attrName = item.tid.GetAttributeName (j);
 std::string value;
 bool ok = chunk->GetAttribute (attrName, value);
 NS_ASSERT (ok);
os << attrName << "=" << value;
                   

another issue with using GetAttributeFullName , when tring to show the attrNAme I get a build faild error :

std::cout<<"fieald name"<<attrName<<std::endl;

the error is  :

assert failed. cond="i < information->attributes.size ()", file=../src/core/model/type-id.cc, line=652

Thank you for helping me find out the accurate methods to use and the cause for the build error or pointing for reading links.

Cordially Hajar

[Hajar Hantouti]

Hello ,
I think I know the source of the build error , actually the portion of code that I'm inspired by is an  #if 0 portion of code that is not compiled in execution , so the build error is caused even in the print method . in depth and still don't know the reason , and how to access header fields. do someone have ideas ?

[Tommaso Pecorella]

Hi,

you're right, that code is commented.

What do you mean by "access header fields" ? Where do you want to access them ?

Cheers,

T.

[Hajar Hantouti]

Hello ,
Thank you for your response.
My goal is to get a field of the Extention header , and based on this information do some treatment. afterwards I aim to modify the field.

Cordially.
Hajar

[Tommaso Pecorella]

Hi,

to be honest I'm quite annoyed by vague answers. It's like asking someone what he/she does for a living and having an answer like "oh, I see people, do things". The first time it's funny, the second time you think that pushing them in the face is an option (albeit a not socially acceptable one).

Now, why I think that your information is vague ? Because it is.

"do some treatment" - of course. WHERE ?

What kind of option header is it, an HbH or an E2E ?

Do you need to process it in-place or to pass this information to some other layer (e.g., routing) ?

Anyway, extension headers are processed in Ipv6Extension::ProcessOptions. Check the function and you'll see why you had to be more precise.

T.

[baddi youssef]

hi,

   as presented in NS3 documentation you can easily add IPv6 extension with IPv6 Extension API (see ipv6-extension.cc):  "IPv6 Extension base If you want to implement a new IPv6 extension, all you have to do is implement a subclass of this class and add it to an Ipv6ExtensionDemux".

  and to process any treatment you can implement ProcessOptions method

Cordially 

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