Add parsing of well known IPv6 extension headers #287
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Add classes for IPv6 extension headers defined in the IPv6 protocol specification (RFC 2460) as well as functions for creating them from the IPv6 class' ext_header type. The currently known extension headers are Hop-By-Hop Option, Destination Routing, Routing and Fragment.
src/ipv6.cpp
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| @@ -169,6 +212,33 @@ uint32_t IPv6::get_padding_size(const ext_header& header) { | |||
| return padding == 0 ? 0 : (8 - padding); | |||
| } | |||
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| std::vector<IPv6::header_option_type> IPv6::parse_header_options(const uint8_t* data, size_t size) | |||
| { | |||
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Can you move this brace up to the end of the previous line?
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Sure. Tried to keep the same coding style as the existing code, but I'm not surprised if I've missed a few places.
src/ipv6.cpp
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| @@ -169,6 +212,33 @@ uint32_t IPv6::get_padding_size(const ext_header& header) { | |||
| return padding == 0 ? 0 : (8 - padding); | |||
| } | |||
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| std::vector<IPv6::header_option_type> IPv6::parse_header_options(const uint8_t* data, size_t size) | |||
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I'm trying to keep cpp files away from using "namespace specifiers" everywhere and instead just have using std::something at the top. In fact, std::vector is already pulled like this so you can just remove std:: here (there's also a couple other occurrences of this in the body of this method).
src/ipv6.cpp
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| } | ||
| if (option != PAD_N) { | ||
| std::vector<uint8_t> value(stream.pointer(), stream.pointer() + size); | ||
| options.push_back(std::make_pair(option, value)); |
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So this sucks because I'm trying to keep the codebase both C++03 and C++11 compliant. If this was C++11 you would do:
options.push_back(make_pair(option, move(value)));So you avoid creating an unnecessary copy of the vector. So in this case you can either have some ugly ifdef TINS_IS_CXX11 and use move, otherwise do what this is moving or you can just move this into a single expression:
options.push_back(make_pair(option, vector<uint8_t>(stream.pointer(), stream.pointer() + size)));Possibly having to split that in multiple lines if it's too long.
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I thought a bit about that actually and was pretty sure the compiler could probably optimize the copy away, but I never tested that.
Anyway since this library has to support C++03, I much prefer your second option over ugly #ifdefs, so I'll go with that.
Well spotted.
src/ipv6.cpp
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| routing_header header; | ||
| header.routing_type = stream.read<uint8_t>(); | ||
| header.segments_left = stream.read<uint8_t>(); | ||
| header.data = std::vector<uint8_t>(stream.pointer(), stream.pointer() + stream.size()); |
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You can just do
header.data.assign(stream.pointer(), stream.pointer() + stream.size());
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Of course. Thanks for pointing this out.
Pull in stuff from the std namespace with "using" instead of qualifying with std::. Keep starting braces on the same line. Avoid potential copy when appending to vector.
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Concerning the protocol format specifics, I haven't really been able to find any pcap files or other ways to tests this with "real life data" so this has mostly but written from what is described in RFC 2460. Since your library makes it incredibly easy to write pcap files, I have tried writing my test data to pcap files and made sure that Wireshark and my code agreed on how the packets should be parsed, but that's the only kind of testing I could really think of. |
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Thanks, looks good! |
Add classes for IPv6 extension headers defined in the IPv6 protocol
specification (RFC 2460) as well as functions for creating them from
the IPv6 class' ext_header type.
The currently known extension headers are Hop-By-Hop Option,
Destination Routing, Routing and Fragment.