/*
	RevArpDaemon.cpp
	
	Reverse ARP Daemon for Alasin
	Copyright (C) 2003 Mike Saywell
	
	Southampton Open Wireless Network,
	http://www.sown.org.uk

	~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~

	This class does the grunt work.  It is responsible for discovering
	the neighbour and assigning an IP address on a single interface.

	It's called RevArpDaemon as traditionally it used ReverseARP to
	do this.  This is no longer the case and class should really be
	renamed, maybe next release eh?

	See Packet.h for details on the protocol.

	~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~

	This program is free software; you can redistribute it and/or
	modify it under the terms of the GNU General Public License
	as published by the Free Software Foundation; either version 2
	of the License, or (at your option) any later version.

	This program is distributed in the hope that it will be useful,
	but WITHOUT ANY WARRANTY; without even the implied warranty of
	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
	GNU General Public License for more details.
	
	You should have received a copy of the GNU General Public License
	along with this program; if not, write to the Free Software
	Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA. 

*/

#include "RevArpDaemon.h"

RevArpDaemon::RevArpDaemon(AddressManager* am, int interface) {
	this->man = am;
	this->sock = socket(PF_PACKET, SOCK_DGRAM, 0);
	this->run = false;

	if(this->sock == -1) {
		cerr << "Failed to create socket " << strerror(errno) << endl;
		exit(1);
	}

	this->if_id = interface;
	
	// Make sure the interface is up
	this->ifup();
	
	// Remove any existing IPs
	this->deAssign();
}

void RevArpDaemon::assign(struct in_addr* network, struct in_addr* netmask, bool master) {

	int ip = 1;

	// IP is from peers address range so we take 2nd address
	if(!master) ip = 2;
	
	struct ifreq* ifr = new struct ifreq;
	ifr->ifr_ifindex = this->if_id;

	if(ioctl(this->sock, SIOCGIFNAME, ifr, sizeof(struct ifreq))==-1) {
		perror("RevArpDaemon::assign(1): ");
	}

	struct sockaddr_in* sin = (struct sockaddr_in*) &ifr->ifr_addr;
	sin->sin_family = AF_INET;

	// IP
	sin->sin_addr.s_addr = network->s_addr+htonl(ip);
	if(ioctl(this->sock, SIOCSIFADDR, ifr, sizeof(struct ifreq))==-1) {
		perror("Setting IP: ");
	}

	// Netmask
	sin->sin_addr.s_addr = netmask->s_addr;
	if(ioctl(this->sock, SIOCSIFNETMASK, ifr, sizeof(struct ifreq))==-1) {
		perror("Setting Netmask: ");
	}
	
	// Broadcast
	sin->sin_addr.s_addr = network->s_addr+htonl(3);
	if(ioctl(this->sock, SIOCSIFBRDADDR, ifr, sizeof(struct ifreq))==-1) {
		perror("Setting Broadcast: ");
	}
}

void RevArpDaemon::deAssign() {
	struct ifreq* ifr = new struct ifreq;
	ifr->ifr_ifindex = this->if_id;

	if(ioctl(this->sock, SIOCGIFNAME, ifr, sizeof(struct ifreq))==-1) {
		perror("RevArpDaemon::assign(1): ");
	}

	struct sockaddr_in* sin = (struct sockaddr_in*) &ifr->ifr_addr;
	sin->sin_family = AF_INET;
	sin->sin_addr.s_addr = htonl(INADDR_ANY);

	if(ioctl(this->sock, SIOCSIFADDR, ifr, sizeof(struct ifreq))==-1) {
		perror("*Removing IP");
	}
	delete ifr;
}

void RevArpDaemon::ifup() {
	struct ifreq* ifr = new struct ifreq;
	ifr->ifr_ifindex = this->if_id;

	if(ioctl(this->sock, SIOCGIFNAME, ifr, sizeof(struct ifreq))==-1) {
		perror("RevArpDaemon (1): ");
	}
	ifr->ifr_flags=IFF_UP;
	if(ioctl(this->sock, SIOCSIFFLAGS, ifr, sizeof(struct ifreq))==-1) {
		perror("RevArpDaemon (2): ");
	}
}

void RevArpDaemon::start() {
	if(this->run)
		return; // don't spawn multiple threads!

	this->run = true;
	pthread_create(&thread, NULL, &radLauncher, this);
}

void* RevArpDaemon::doMain() {
	Packet* p = new Packet(ALADIN_HELLO);

	char device[IF_NAMESIZE];
	if_indextoname(this->if_id, device);

	while (this->run) {
		p->reset();
		p->setType(ALADIN_HELLO);

		if (Packet::send(p, this->if_id) < 0) {
			this->run = false;
			continue;
		}
		if (DEBUG) cerr << "Sent HELLO on " << device << endl;

		// Listen for replies over next 10 seconds
		if (Packet::receive(p, this->if_id, 10) < 0) {
			continue;
		}

		// The other party has responded to our HELLO
		if(p->getType() == ALADIN_ACK) {
			if (DEBUG) cerr << "Rcvd ACK on " << device << endl;

			// Wait a second
			sleep(1);

			// Send a REQUEST
			p->reset();
			p->setType(ALADIN_REQUEST);

			if (Packet::send(p, this->if_id) < 0) {
				this->run = false;
				continue;
			}
			if (DEBUG) cerr << "Sent REQUEST on " << device << endl;
				
			// Listen for replies over next 10 seconds
			if (Packet::receive(p, this->if_id, 10) < 0) {
				continue;
			}

			// Check for ALADIN_REPLY
			if(p->getType() == ALADIN_REPLY) {

				struct in_addr* network = new struct in_addr;
				struct in_addr* netmask = new struct in_addr;

				network->s_addr = p->getNetwork();
				netmask->s_addr = p->getNetmask();

				if (DEBUG) {
					cerr << "Rcvd REPLY on " << device << endl;

					cout << "Network: " << inet_ntoa(*network) << endl;
					cout << "Netmask: " << inet_ntoa(*netmask) << endl;

				}

				this->assign(network, netmask, false);

				delete network;
				delete netmask;
						
				// Wait a second
				sleep(1);

				// Send an ACK
				p->reset();
				p->setType(ALADIN_ACK);

				if(Packet::send(p, this->if_id) < 0) {
					this->run = false;
					continue;
				}
				if (DEBUG) cerr << "Sent ACK on " << device << endl;

				int loop = 0;

				// Enter ACK loop
				while (loop < 3) {
					if (Packet::receive(p, this->if_id, 10) < 0) {
						loop++;
						if (DEBUG) cerr << "No reply to HELLO, if " << device << ", try " << loop << endl;
					}
					else {
						// Check for ALADIN_ACK
						if(p->getType() == ALADIN_ACK) {
							loop = 0;
							if (DEBUG) cerr << "Rcvd ACK on " << device << endl << "(sleeping)" << endl;

							// Sleeeeep
							sleep(5);
						}
						else {
							if (DEBUG) cerr << "Rcvd non-ACK on " << device << ", restarting." << endl;
							loop = 3;
							continue;
						}
					}
					// Send an ACK
					p->reset();
					p->setType(ALADIN_ACK);
					if(Packet::send(p, this->if_id) < 0) {
						this->run = false;
						loop = 3;
						continue;
					}
					if (DEBUG) cerr << "Sent ACK on " << device << endl;
				}
				if (DEBUG) cerr << "Peer has vanished, removing IP from " << device << endl;
				this->deAssign();
			}
			else {
				char tmp[64];
				p->prnType(tmp);
				if (DEBUG) cerr << "Expected REPLY but got " << tmp << "!" << endl;
			}
				
		}

		// The other party has missed our HELLO, so we'll ACK
		else if(p->getType() == ALADIN_HELLO) {
			if (DEBUG) cerr << "Rcvd HELLO on " << device << endl;

			// Allocate the address now, if this fails
			// we can ignore the HELLO and request an
			// IP from the peers pool
			struct AddressAllocation* address = this->man->allocate();
			this->man->deallocate(address);
			address = this->man->allocate();

			if(!address) {
				cerr << "Failed to get an IP allocation (configure a bigger address range!)" << endl;
				continue;
			}

			if (DEBUG) {
				cerr << "Got network allocation of " << inet_ntoa(address->network);
				cerr << "/" << inet_ntoa(address->netmask) << endl;
				cerr << "For interface " << device << endl;
			}

			// Wait a second
			sleep(1);

			// Send an ACK
			p->reset();
			p->setType(ALADIN_ACK);
			if(Packet::send(p, this->if_id) < 0) {
				this->run = false;
				continue;
			}
			if (DEBUG) cerr << "Sent ACK on " << device << endl;

			// Listen for replies over next 10 seconds
			if (Packet::receive(p, this->if_id, 10) < 0) {
				continue;
			}

			// Check for ALADIN_REQUEST
			if(p->getType() == ALADIN_REQUEST) {
				if (DEBUG) cerr << "Rcvd REQUEST on " << device << endl;

				// Wait a second
				sleep(1);

				// Send a REPLY
				p->reset();
				p->setType(ALADIN_REPLY);
				p->setNetwork(&address->network);
				p->setNetmask(&address->netmask);

				if(Packet::send(p, this->if_id) < 0) {
					this->run = false;
					continue;
				}
				if (DEBUG) cerr << "Sent REPLY on " << device << endl;

				// Listen for replies over next 10 seconds
				if (Packet::receive(p, this->if_id, 10) < 0) {
					continue;
				}

				// Check for ALADIN_ACK
				if(p->getType() == ALADIN_ACK) {
					// Peer has accepted the address
					this->assign(&address->network, &address->netmask, true);

					sleep(1);

					// Send an ACK
					p->reset();
					p->setType(ALADIN_ACK);
					if(Packet::send(p, this->if_id) < 0) {
						this->run = false;
						continue;
					}

					if (DEBUG) cerr << "Sent ACK on " << device << endl;

					int loop = 0;

					// Enter ACK loop
					while (loop < 3) {
						if (Packet::receive(p, this->if_id, 10) < 0) {
							loop++;
							if (DEBUG) cerr << "No reply to HELLO, if " << device << ", try " << loop << endl;
						}
						else {
							// Check for ALADIN_ACK
							if(p->getType() == ALADIN_ACK) {
								loop = 0;
								if (DEBUG) cerr << "Rcvd ACK on " << device << endl << "(sleeping)" << endl;

								// Sleeeeep
								sleep(5);
							}
							else {
								if (DEBUG) cerr << "Rcvd non-ACK on " << device << endl << "(sleeping)" << endl;
								loop++;
							}
						}

						// Send an ACK
						p->reset();
						p->setType(ALADIN_ACK);
						if(Packet::send(p, this->if_id) < 0) {
							this->run = false;
							loop = 3;
							continue;
						}
						if (DEBUG) cerr << "Sent ACK on " << device << endl;
					}
					if (DEBUG) cerr << "Peer has vanished, removing IP from " << device << endl;
					this->deAssign();
				}
			}
			// De-allocate the address
			this->man->deallocate(address);
		}
		sleep(2);
	}
	delete p;
	this->run = false;
	cerr << "RevArpDaemon is terminating on interface " << if_id << endl;
}

void RevArpDaemon::stop() {
	this->run = false;
}

bool RevArpDaemon::isRunning() {
	return this->run;
}

void* radLauncher(void *obj) {
        return static_cast<RevArpDaemon*>(obj)->doMain();
}