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7cedf7ae71
This patch aims to fix three closely related issues. o The implementation of IPV6_FRAG_COPYHEADER was fundamentally incompatible with the presence of extension headers between the IPv6 header and the Fragment Header. This patch changes the implementation to support such extension headers as well, with pretty much the same memory requirements. As a result, we can remove the check that prevented such packets from being reassembled in all cases, even with IPV6_FRAG_COPYHEADER off. o Given that temporary data is stored in the Fragment Header of packets saved for the purpose of reassembly, but ICMPv6 "Fragment Reassembly Time Exceeded" packets contain part of the original packet, such ICMPv6 packets could actually end up containing part of the temporary data, which may even include a pointer value. The ICMPv6 packet should contain the original, unchanged packet, so save the original header data before overwriting it even if IPV6_FRAG_COPYHEADER is disabled. This does add some extra memory consumption. o Previously, the reassembly would leave the fragment header in the reassembled packet, which is not permitted by RFC 2460 and prevents reassembly of particularly large packets (close to 65535 bytes after reassembly). This patch gets rid of the fragment header. It does require an implementation of memmove() for that purpose. Note that this patch aims to improve correctness. Future changes might restore some of the previous functionality in order to regain optimal performance for certain cases (at the cost of more code).