//  Copyright © 2020 Marius Petrescu (YO2LOJ). All rights reserved.

// ulxd -- The universal reflector
// Copyright © 2021 Thomas A. Early N7TAE
//
// 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 3 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, see <https://www.gnu.org/licenses/>.

#include "Main.h"
#include <string.h>
#include "Reflector.h"
#include "RawSocket.h"


////////////////////////////////////////////////////////////////////////////////////////
// constructor

CRawSocket::CRawSocket()
{
	m_Socket = -1;
}

////////////////////////////////////////////////////////////////////////////////////////
// destructor

CRawSocket::~CRawSocket()
{
	if ( m_Socket != -1 )
	{
		Close();
	}
}

////////////////////////////////////////////////////////////////////////////////////////
// open & close

bool CRawSocket::Open(uint16_t uiProto)
{
	bool open = false;
	int on = 1;

	// create socket
	m_Socket = socket(AF_INET, SOCK_RAW, uiProto);
	if ( m_Socket != -1 )
	{
		fcntl(m_Socket, F_SETFL, O_NONBLOCK);
		open = true;
		m_Proto = uiProto;
	}

	// done
	return open;
}

void CRawSocket::Close(void)
{
	if ( m_Socket != -1 )
	{
		close(m_Socket);
		m_Socket = -1;
	}
}

////////////////////////////////////////////////////////////////////////////////////////
// read

int CRawSocket::Receive(uint8_t *Buffer, CIp *Ip, int timeout)
{
	struct sockaddr_in Sin;
	fd_set FdSet;
	unsigned int uiFromLen = sizeof(struct sockaddr_in);
	int iRecvLen = -1;
	struct timeval tv;

	// socket valid ?
	if ( m_Socket != -1 )
	{
		// control socket
		FD_ZERO(&FdSet);
		FD_SET(m_Socket, &FdSet);
		tv.tv_sec = timeout / 1000;
		tv.tv_usec = (timeout % 1000) * 1000;
		select(m_Socket + 1, &FdSet, 0, 0, &tv);

		// read
		iRecvLen = (int)recvfrom(m_Socket, Buffer, RAW_BUFFER_LENMAX, 0, (struct sockaddr *)&Sin, &uiFromLen);

		// handle
		if ( iRecvLen != -1 )
		{
			// get IP
			memcpy(Ip->GetPointer(), &Sin, sizeof(struct sockaddr_in));
		}
	}

	// done
	return iRecvLen;
}

// protocol specific

// ICMP

int CRawSocket::IcmpReceive(uint8_t *Buffer, CIp *Ip, int timeout)
{
	int iIcmpType = -1;
	int iRecv;

	if (m_Proto == IPPROTO_ICMP)
	{
		iRecv = Receive(Buffer, Ip, timeout);

		if (iRecv >= (int)(sizeof(struct ip) + sizeof(struct icmp)))
		{
			struct ip *iph = (struct ip *)Buffer;
			int iphdrlen = iph->ip_hl * 4;
			struct icmp *icmph = (struct icmp *)((unsigned char *)iph + iphdrlen);
			struct ip *remote_iph = (struct ip *)((unsigned char *)icmph + 8);

			iIcmpType = icmph->icmp_type;

			struct sockaddr_in Sin;
			bzero(&Sin, sizeof(Sin));
			Sin.sin_family = AF_INET;
			Sin.sin_addr.s_addr = remote_iph->ip_dst.s_addr;

			memcpy(Ip->GetPointer(), &Sin, sizeof(struct sockaddr_in));

		}
	}
	return iIcmpType;
}