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Code Issues Releases Wiki Activity

Keep first fragment during IPv4 reassembly

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Fixes #225
This commit is contained in:
Matias Fontanini
2017-09-10 16:39:15 -07:00
parent 78b94fa350
commit 171067eb22
3 changed files with 36 additions and 9 deletions
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15
src/ip_reassembler.cpp
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@@ -38,11 +38,17 @@ namespace Tins {
namespace Internals {
IPv4Stream::IPv4Stream()
: received_end_(false), transport_proto_(0xff), received_size_(), total_size_() {
: received_size_(), total_size_(), received_end_(false), transport_proto_(0xff) {
}
void IPv4Stream::add_fragment(IP* ip) {
if (fragments_.empty()) {
// Release the inner PDU, store this first fragment and restore the inner PDU
PDU* inner_pdu = ip->release_inner_pdu();
first_fragment_ = *ip;
ip->inner_pdu(inner_pdu);
}
fragments_type::iterator it = fragments_.begin();
uint16_t offset = extract_offset(ip);
while (it != fragments_.end() && offset > it->offset()) {
@@ -87,6 +93,10 @@ PDU* IPv4Stream::allocate_pdu() const {
);
}
const IP& IPv4Stream::first_fragment() const {
return first_fragment_;
}
uint16_t IPv4Stream::extract_offset(const IP* ip) {
return ip->fragment_offset() * 8;
}
@@ -114,6 +124,9 @@ IPv4Reassembler::PacketStatus IPv4Reassembler::process(PDU& pdu) {
stream.add_fragment(ip);
if (stream.is_complete()) {
PDU* pdu = stream.allocate_pdu();
// Use all field values from the first fragment
*ip = stream.first_fragment();
// Erase this stream, since it's already assembled
streams_.erase(key);
// The packet is corrupt