M1-nw-project/packetParser.cpp

/***************************************************************************
 * By Théophile Bastian, 2017
 * M1 Network course project at ENS Cachan, Juliusz Chroboczek.
 * License: WTFPL v2 <http://www.wtfpl.net/>
 **************************************************************************/

#include "packetParser.h"
#include <cstring>

PacketParser::PacketParser(Neighbours* nei, Protocol* proto,
		DataStore* dataStore) :
	neighbours(nei), protocol(proto), dataStore(dataStore)
{}

void PacketParser::parse(Bytes pck, const SockAddr& addr) {
	u64 peerId;
	if(pck.size() < 8) {
		fprintf(stderr, "[WARNING] Bad packet size.\n");
		return;
	}

	pck >> peerId;
	neighbours->receivedFrom(peerId, addr);

	while(pck.size() > 0) {
		readTLV(pck, peerId, addr);
	}
}

void PacketParser::readTLV(Bytes& pck, u64 nei, const SockAddr& addr) {
	u8 type, len;
	if(pck.size() < 2) {
		fprintf(stderr, "[WARNING] Bad packet size from %lX.\n", nei);
		return;
	}
	pck >> type >> len;

	fprintf(stderr, "[INFO] Parsing %d from %lX.\n", type, nei);

	if(pck.size() < len) {
		fprintf(stderr, "[WARNING] Advertised TLV does not fit in the packet"
				".\n");
		pck.extract(pck.size());
		return;
	}
	Bytes subpacket = pck.extract(len);

	switch(type) {
		case csts::TLV_PAD1:
		case csts::TLV_PADN:
			break;

		case csts::TLV_IHU: {
			u64 ihuId;
			subpacket >> ihuId;
			if(ihuId != protocol->getSelfId())
				break;

			neighbours->hadIHU(nei, addr);
			break;
		}

		case csts::TLV_NR:
			handleNR(nei);
			break;

		case csts::TLV_NEIGH:
			receiveNeigh(subpacket);
			break;

		case csts::TLV_DATA:
			receiveData(subpacket, nei);
			break;

		case csts::TLV_IHAVE:
			receiveIHave(subpacket, nei);
			break;
	}
}

void PacketParser::receiveNeigh(Bytes& pck) {
	while(pck.size() >= 8+16+2) { /* enough to read one peer */
		u64 id;
		u16 port;
		SockAddr addr;
		memset(&addr, 0, sizeof(addr));
		addr.sin6_family = AF_INET6;

		pck >> id;
		for(int byte=0; byte < 16; byte++)
			pck >> addr.sin6_addr.s6_addr[byte];
		pck >> port;
		addr.sin6_port = htons(port);

		if(id == protocol->getSelfId())
			continue;

		Neighbour nei(id, addr);
		neighbours->addPotentialNei(nei);
	}
}

void PacketParser::receiveData(Bytes& pck, u64 from) {
	u32 seqNo;
	u64 datId;
	pck >> seqNo >> datId;
	neighbours->gotIHave(from, datId, seqNo);
	protocol->sendIHave(from, datId, seqNo);
	dataStore->addData(pck, seqNo, datId, false);
}

void PacketParser::receiveIHave(Bytes& pck, u64 from) {
	u32 seqno;
	u64 datId;
	if(pck.size() < 8+4) {
		fprintf(stderr, "[WARNING] IHave too short from %lX\n", from);
		return;
	}
	pck >> seqno >> datId;
	neighbours->gotIHave(from, datId, seqno);
}

void PacketParser::handleNR(u64 from) {
	std::vector<Neighbour> neigh;
	neighbours->getNeighbours(neigh, from, csts::NB_NEIGH_PER_NR);

	protocol->sendNeighbours(from, neigh);
}