/*
 * connection.cpp
 *
 *  Created on: Sep 23, 2017
 *      Author: root
 */

#include "connection.h"
#include "encrypt.h"


int disable_anti_replay=0;//if anti_replay windows is diabled

const int disable_conv_clear=0;//a udp connection in the multiplexer is called conversation in this program,conv for short.

const int disable_conn_clear=0;//a raw connection is called conn.


	anti_replay_seq_t anti_replay_t::get_new_seq_for_send()
	{
		return anti_replay_seq++;
	}
	anti_replay_t::anti_replay_t()
	{
		max_packet_received=0;
		anti_replay_seq=get_true_random_number_64()/10;//random first seq
		//memset(window,0,sizeof(window)); //not necessary
	}
	void anti_replay_t::re_init()
	{
		max_packet_received=0;
		//memset(window,0,sizeof(window));
	}

	int anti_replay_t::is_vaild(u64_t seq)
	{
		if(disable_anti_replay) return 1;
		//if(disabled) return 0;

		if(seq==max_packet_received) return 0;
		else if(seq>max_packet_received)
		{
			if(seq-max_packet_received>=anti_replay_window_size)
			{
				memset(window,0,sizeof(window));
				window[seq%anti_replay_window_size]=1;
			}
			else
			{
				for (u64_t i=max_packet_received+1;i<seq;i++)
					window[i%anti_replay_window_size]=0;
				window[seq%anti_replay_window_size]=1;
			}
			max_packet_received=seq;
			return 1;
		}
		else if(seq<max_packet_received)
		{
			if(max_packet_received-seq>=anti_replay_window_size) return 0;
			else
			{
				if (window[seq%anti_replay_window_size]==1) return 0;
				else
				{
					window[seq%anti_replay_window_size]=1;
					return 1;
				}
			}
		}


		return 0; //for complier check
	}


void server_clear_function(u64_t u64);

conv_manager_t::conv_manager_t()
	{
		clear_it=conv_last_active_time.begin();
		long long last_clear_time=0;
		//clear_function=0;
	}
conv_manager_t::~conv_manager_t()
	{
		clear();
	}
	int conv_manager_t::get_size()
	{
		return conv_to_u64.size();
	}
	void conv_manager_t::reserve()
	{
		u64_to_conv.reserve(10007);
		conv_to_u64.reserve(10007);
		conv_last_active_time.reserve(10007);
	}
	void conv_manager_t::clear()
	{
		if(disable_conv_clear) return ;

		if(program_mode==server_mode)
		{
			for(it=conv_to_u64.begin();it!=conv_to_u64.end();it++)
			{
				//int fd=int((it->second<<32u)>>32u);
				server_clear_function(  it->second);
			}
		}
		u64_to_conv.clear();
		conv_to_u64.clear();
		conv_last_active_time.clear();

		clear_it=conv_last_active_time.begin();

	}
	u32_t conv_manager_t::get_new_conv()
	{
		u32_t conv=get_true_random_number_nz();
		while(conv_to_u64.find(conv)!=conv_to_u64.end())
		{
			conv=get_true_random_number_nz();
		}
		return conv;
	}
	int conv_manager_t::is_conv_used(u32_t conv)
	{
		return conv_to_u64.find(conv)!=conv_to_u64.end();
	}
	int conv_manager_t::is_u64_used(u64_t u64)
	{
		return u64_to_conv.find(u64)!=u64_to_conv.end();
	}
	u32_t conv_manager_t::find_conv_by_u64(u64_t u64)
	{
		return u64_to_conv[u64];
	}
	u64_t conv_manager_t::find_u64_by_conv(u32_t conv)
	{
		return conv_to_u64[conv];
	}
	int conv_manager_t::update_active_time(u32_t conv)
	{
		return conv_last_active_time[conv]=get_current_time();
	}
	int conv_manager_t::insert_conv(u32_t conv,u64_t u64)
	{
		u64_to_conv[u64]=conv;
		conv_to_u64[conv]=u64;
		conv_last_active_time[conv]=get_current_time();
		return 0;
	}
	int conv_manager_t::erase_conv(u32_t conv)
	{
		if(disable_conv_clear) return 0;
		u64_t u64=conv_to_u64[conv];
		if(program_mode==server_mode)
		{
			server_clear_function(u64);
		}
		conv_to_u64.erase(conv);
		u64_to_conv.erase(u64);
		conv_last_active_time.erase(conv);
		return 0;
	}
	int conv_manager_t::clear_inactive(char * ip_port)
	{
		if(get_current_time()-last_clear_time>conv_clear_interval)
		{
			last_clear_time=get_current_time();
			return clear_inactive0(ip_port);
		}
		return 0;
	}
	int conv_manager_t::clear_inactive0(char * ip_port)
	{
		if(disable_conv_clear) return 0;


		//map<uint32_t,uint64_t>::iterator it;
		int cnt=0;
		it=clear_it;
		int size=conv_last_active_time.size();
		int num_to_clean=size/conv_clear_ratio+conv_clear_min;   //clear 1/10 each time,to avoid latency glitch

		num_to_clean=min(num_to_clean,size);

		u64_t current_time=get_current_time();
		for(;;)
		{
			if(cnt>=num_to_clean) break;
			if(conv_last_active_time.begin()==conv_last_active_time.end()) break;

			if(it==conv_last_active_time.end())
			{
				it=conv_last_active_time.begin();
			}

			if( current_time -it->second  >conv_timeout )
			{
				//mylog(log_info,"inactive conv %u cleared \n",it->first);
				old_it=it;
				it++;
				u32_t conv= old_it->first;
				erase_conv(old_it->first);
				if(ip_port==0)
				{
					mylog(log_info,"conv %x cleared\n",conv);
				}
				else
				{
					mylog(log_info,"[%s]conv %x cleared\n",ip_port,conv);
				}
			}
			else
			{
				it++;
			}
			cnt++;
		}
		return 0;
	}


	 void conn_info_t::recover(const conn_info_t &conn_info)
	 {
			raw_info=conn_info.raw_info;
			last_state_time=conn_info.last_state_time;
			last_hb_recv_time=conn_info.last_hb_recv_time;
			last_hb_sent_time=conn_info.last_hb_sent_time;
			my_id=conn_info.my_id;
			oppsite_id=conn_info.oppsite_id;
			blob->anti_replay.re_init();

			my_roller=0;//no need to set,but for easier debug,set it to zero
			oppsite_roller=0;//same as above
			last_oppsite_roller_time=0;
	 }

	void conn_info_t::re_init()
	{
		//send_packet_info.protocol=g_packet_info_send.protocol;
		if(program_mode==server_mode)
			state.server_current_state=server_idle;
		else
			state.client_current_state=client_idle;
		last_state_time=0;
		oppsite_const_id=0;

		timer_fd=0;

		my_roller=0;
		oppsite_roller=0;
		last_oppsite_roller_time=0;
	}
	conn_info_t::conn_info_t()
	{
		blob=0;
		re_init();
	}
	void conn_info_t::prepare()
	{
		blob=new blob_t;

	}
	conn_info_t::conn_info_t(const conn_info_t&b)
	{
		//mylog(log_error,"called!!!!!!!!!!!!!\n");
		*this=b;
		if(blob!=0)
		{
			blob=new blob_t(*b.blob);
		}
	}
	conn_info_t& conn_info_t::operator=(const conn_info_t& b)
	  {
		mylog(log_fatal,"not allowed\n");
		myexit(-1);
	    return *this;
	  }
	conn_info_t::~conn_info_t()
	{
		if(program_mode==server_mode)
		{
			if(state.server_current_state==server_ready)
			{
				assert(blob!=0);
				assert(oppsite_const_id!=0);
				//assert(conn_manager.const_id_mp.find(oppsite_const_id)!=conn_manager.const_id_mp.end()); // conn_manager 's deconstuction function  erases it
			}
			else
			{
				assert(blob==0);
				assert(oppsite_const_id==0);
			}
		}
		//if(oppsite_const_id!=0)     //do this at conn_manager 's deconstuction function
			//conn_manager.const_id_mp.erase(oppsite_const_id);
		if(blob!=0)
			delete blob;

		//send_packet_info.protocol=g_packet_info_send.protocol;
	}


	conn_manager_t::conn_manager_t()
 {
	 ready_num=0;
	 mp.reserve(10007);
	 clear_it=mp.begin();
	 timer_fd_mp.reserve(10007);
	 const_id_mp.reserve(10007);
	 udp_fd_mp.reserve(100007);
	 last_clear_time=0;
	 //current_ready_ip=0;
	// current_ready_port=0;
 }
 int conn_manager_t::exist(u32_t ip,uint16_t port)
 {
	 u64_t u64=0;
	 u64=ip;
	 u64<<=32u;
	 u64|=port;
	 if(mp.find(u64)!=mp.end())
	 {
		 return 1;
	 }
	 return 0;
 }
 /*
 int insert(uint32_t ip,uint16_t port)
 {
	 uint64_t u64=0;
	 u64=ip;
	 u64<<=32u;
	 u64|=port;
	 mp[u64];
	 return 0;
 }*/
 conn_info_t *& conn_manager_t::find_insert_p(u32_t ip,uint16_t port)  //be aware,the adress may change after rehash
 {
	 u64_t u64=0;
	 u64=ip;
	 u64<<=32u;
	 u64|=port;
	 unordered_map<u64_t,conn_info_t*>::iterator it=mp.find(u64);
	 if(it==mp.end())
	 {
		 mp[u64]=new conn_info_t;
	 }
	 return mp[u64];
 }
 conn_info_t & conn_manager_t::find_insert(u32_t ip,uint16_t port)  //be aware,the adress may change after rehash
 {
	 u64_t u64=0;
	 u64=ip;
	 u64<<=32u;
	 u64|=port;
	 unordered_map<u64_t,conn_info_t*>::iterator it=mp.find(u64);
	 if(it==mp.end())
	 {
		 mp[u64]=new conn_info_t;
	 }
	 return *mp[u64];
 }
 int conn_manager_t::erase(unordered_map<u64_t,conn_info_t*>::iterator erase_it)
 {
		if(erase_it->second->state.server_current_state==server_ready)
		{
			ready_num--;
			assert(i32_t(ready_num)!=-1);
			assert(erase_it->second!=0);
			assert(erase_it->second->timer_fd !=0);
			assert(erase_it->second->oppsite_const_id!=0);
			assert(const_id_mp.find(erase_it->second->oppsite_const_id)!=const_id_mp.end());
			assert(timer_fd_mp.find(erase_it->second->timer_fd)!=timer_fd_mp.end());

			const_id_mp.erase(erase_it->second->oppsite_const_id);
			timer_fd_mp.erase(erase_it->second->timer_fd);
			close(erase_it->second->timer_fd);// close will auto delte it from epoll
			delete(erase_it->second);
			mp.erase(erase_it->first);
		}
		else
		{
			assert(erase_it->second->blob==0);
			assert(erase_it->second->timer_fd ==0);
			assert(erase_it->second->oppsite_const_id==0);
			delete(erase_it->second);
			mp.erase(erase_it->first);
		}
		return 0;
 }
int conn_manager_t::clear_inactive()
{
	if(get_current_time()-last_clear_time>conn_clear_interval)
	{
		last_clear_time=get_current_time();
		return clear_inactive0();
	}
	return 0;
}
int conn_manager_t::clear_inactive0()
{
	 unordered_map<u64_t,conn_info_t*>::iterator it;
	 unordered_map<u64_t,conn_info_t*>::iterator old_it;

	if(disable_conn_clear) return 0;

	//map<uint32_t,uint64_t>::iterator it;
	int cnt=0;
	it=clear_it;
	int size=mp.size();
	int num_to_clean=size/conn_clear_ratio+conn_clear_min;   //clear 1/10 each time,to avoid latency glitch

	mylog(log_trace,"mp.size() %d\n", size);

	num_to_clean=min(num_to_clean,(int)mp.size());
	u64_t current_time=get_current_time();

	for(;;)
	{
		if(cnt>=num_to_clean) break;
		if(mp.begin()==mp.end()) break;

		if(it==mp.end())
		{
			it=mp.begin();
		}

		if(it->second->state.server_current_state==server_ready &&current_time - it->second->last_hb_recv_time  <=server_conn_timeout)
		{
				it++;
		}
		else if(it->second->state.server_current_state!=server_ready&& current_time - it->second->last_state_time  <=server_handshake_timeout )
		{
			it++;
		}
		else if(it->second->blob!=0&&it->second->blob->conv_manager.get_size() >0)
		{
			assert(it->second->state.server_current_state==server_ready);
			it++;
		}
		else
		{
			mylog(log_info,"[%s:%d]inactive conn cleared \n",my_ntoa(it->second->raw_info.recv_info.src_ip),it->second->raw_info.recv_info.src_port);
			old_it=it;
			it++;
			erase(old_it);
		}
		cnt++;
	}
	return 0;
}




int send_bare(raw_info_t &raw_info,const char* data,int len)//send function with encryption but no anti replay,this is used when client and server verifys each other
//you have to design the protocol carefully, so that you wont be affect by relay attack
{
	if(len<0)
	{
		mylog(log_debug,"input_len <0\n");
		return -1;
	}
	packet_info_t &send_info=raw_info.send_info;
	packet_info_t &recv_info=raw_info.recv_info;

	char send_data_buf[buf_len];  //buf for send data and send hb
	char send_data_buf2[buf_len];


	//static send_bare[buf_len];
	iv_t iv=get_true_random_number_64();
	padding_t padding=get_true_random_number_64();

	memcpy(send_data_buf,&iv,sizeof(iv));
	memcpy(send_data_buf+sizeof(iv),&padding,sizeof(padding));

	send_data_buf[sizeof(iv)+sizeof(padding)]='b';
	memcpy(send_data_buf+sizeof(iv)+sizeof(padding)+1,data,len);
	int new_len=len+sizeof(iv)+sizeof(padding)+1;

	if(my_encrypt(send_data_buf,send_data_buf2,new_len,key)!=0)
	{
		return -1;
	}
	send_raw0(raw_info,send_data_buf2,new_len);
	return 0;
}
int reserved_parse_bare(const char *input,int input_len,char* & data,int & len) // a sub function used in recv_bare
{
	static char recv_data_buf[buf_len];

	if(input_len<0)
	{
		mylog(log_debug,"input_len <0\n");
		return -1;
	}
	if(my_decrypt(input,recv_data_buf,input_len,key)!=0)
	{
		mylog(log_debug,"decrypt_fail in recv bare\n");
		return -1;
	}
	if(recv_data_buf[sizeof(iv_t)+sizeof(padding_t)]!='b')
	{
		mylog(log_debug,"not a bare packet\n");
		return -1;
	}
	len=input_len;
	data=recv_data_buf+sizeof(iv_t)+sizeof(padding_t)+1;
	len-=sizeof(iv_t)+sizeof(padding_t)+1;
	if(len<0)
	{
		mylog(log_debug,"len <0\n");
		return -1;
	}
	return 0;
}
int recv_bare(raw_info_t &raw_info,char* & data,int & len)//recv function with encryption but no anti replay,this is used when client and server verifys each other
//you have to design the protocol carefully, so that you wont be affect by relay attack
{
	packet_info_t &send_info=raw_info.send_info;
	packet_info_t &recv_info=raw_info.recv_info;

	if(recv_raw0(raw_info,data,len)<0)
	{
		//printf("recv_raw_fail in recv bare\n");
		return -1;
	}
	if ((raw_mode == mode_faketcp && (recv_info.syn == 1 || recv_info.ack != 1)))
	{
		mylog(log_debug,"unexpect packet type recv_info.syn=%d recv_info.ack=%d \n",recv_info.syn,recv_info.ack);
		return -1;
	}
	return reserved_parse_bare(data,len,data,len);
}

int send_handshake(raw_info_t &raw_info,id_t id1,id_t id2,id_t id3)// a warp for send_bare for sending handshake(this is not tcp handshake) easily
{
	packet_info_t &send_info=raw_info.send_info;
	packet_info_t &recv_info=raw_info.recv_info;

	char * data;int len;
	//len=sizeof(id_t)*3;
	if(numbers_to_char(id1,id2,id3,data,len)!=0) return -1;
	if(send_bare(raw_info,data,len)!=0) {mylog(log_warn,"send bare fail\n");return -1;}
	return 0;
}
/*
int recv_handshake(packet_info_t &info,id_t &id1,id_t &id2,id_t &id3)
{
	char * data;int len;
	if(recv_bare(info,data,len)!=0) return -1;

	if(char_to_numbers(data,len,id1,id2,id3)!=0) return -1;

	return 0;
}*/

int send_safer(conn_info_t &conn_info,char type,const char* data,int len)  //safer transfer function with anti-replay,when mutually verification is done.
{

	packet_info_t &send_info=conn_info.raw_info.send_info;
	packet_info_t &recv_info=conn_info.raw_info.recv_info;

	if(type!='h'&&type!='d')
	{
		mylog(log_warn,"first byte is not h or d  ,%x\n",type);
		return -1;
	}



	char send_data_buf[buf_len];  //buf for send data and send hb
	char send_data_buf2[buf_len];



	id_t n_tmp_id=htonl(conn_info.my_id);

	memcpy(send_data_buf,&n_tmp_id,sizeof(n_tmp_id));

	n_tmp_id=htonl(conn_info.oppsite_id);

	memcpy(send_data_buf+sizeof(n_tmp_id),&n_tmp_id,sizeof(n_tmp_id));

	anti_replay_seq_t n_seq=hton64(conn_info.blob->anti_replay.get_new_seq_for_send());

	memcpy(send_data_buf+sizeof(n_tmp_id)*2,&n_seq,sizeof(n_seq));


	send_data_buf[sizeof(n_tmp_id)*2+sizeof(n_seq)]=type;
	send_data_buf[sizeof(n_tmp_id)*2+sizeof(n_seq)+1]=conn_info.my_roller;

	memcpy(send_data_buf+2+sizeof(n_tmp_id)*2+sizeof(n_seq),data,len);//data;

	int new_len=len+sizeof(n_seq)+sizeof(n_tmp_id)*2+2;

	if(my_encrypt(send_data_buf,send_data_buf2,new_len,key)!=0)
	{
		return -1;
	}

	if(send_raw0(conn_info.raw_info,send_data_buf2,new_len)!=0) return -1;

	if(after_send_raw0(conn_info.raw_info)!=0) return -1;

	return 0;
}
int send_data_safer(conn_info_t &conn_info,const char* data,int len,u32_t conv_num)//a wrap for  send_safer for transfer data.
{
	packet_info_t &send_info=conn_info.raw_info.send_info;
	packet_info_t &recv_info=conn_info.raw_info.recv_info;

	char send_data_buf[buf_len];
	//send_data_buf[0]='d';
	u32_t n_conv_num=htonl(conv_num);
	memcpy(send_data_buf,&n_conv_num,sizeof(n_conv_num));

	memcpy(send_data_buf+sizeof(n_conv_num),data,len);
	int new_len=len+sizeof(n_conv_num);
	send_safer(conn_info,'d',send_data_buf,new_len);
	return 0;

}
int parse_safer(conn_info_t &conn_info,const char * input,int input_len,char &type,char* &data,int &len)//subfunction for recv_safer,allow overlap
{
	 static char recv_data_buf[buf_len];

	// char *recv_data_buf=recv_data_buf0; //fix strict alias warning
	if(my_decrypt(input,recv_data_buf,input_len,key)!=0)
	{
		//printf("decrypt fail\n");
		return -1;
	}



	//char *a=recv_data_buf;
	//id_t h_oppiste_id= ntohl (  *((id_t * )(recv_data_buf)) );
	id_t h_oppsite_id;
	memcpy(&h_oppsite_id,recv_data_buf,sizeof(h_oppsite_id));
	h_oppsite_id=ntohl(h_oppsite_id);

	//id_t h_my_id= ntohl (  *((id_t * )(recv_data_buf+sizeof(id_t)))    );
	id_t h_my_id;
	memcpy(&h_my_id,recv_data_buf+sizeof(id_t),sizeof(h_my_id));
	h_my_id=ntohl(h_my_id);

	//anti_replay_seq_t h_seq= ntoh64 (  *((anti_replay_seq_t * )(recv_data_buf  +sizeof(id_t) *2 ))   );
	anti_replay_seq_t h_seq;
	memcpy(&h_seq,recv_data_buf  +sizeof(id_t) *2 ,sizeof(h_seq));
	h_seq=ntoh64(h_seq);

	if(h_oppsite_id!=conn_info.oppsite_id||h_my_id!=conn_info.my_id)
	{
		mylog(log_debug,"id and oppsite_id verification failed %x %x %x %x \n",h_oppsite_id,conn_info.oppsite_id,h_my_id,conn_info.my_id);
		return -1;
	}

	if (conn_info.blob->anti_replay.is_vaild(h_seq) != 1) {
		mylog(log_debug,"dropped replay packet\n");
		return -1;
	}

	//printf("recv _len %d\n ",recv_len);
	data=recv_data_buf+sizeof(anti_replay_seq_t)+sizeof(id_t)*2;
	len=input_len-(sizeof(anti_replay_seq_t)+sizeof(id_t)*2  );


	if(data[0]!='h'&&data[0]!='d')
	{
		mylog(log_debug,"first byte is not h or d  ,%x\n",data[0]);
		return -1;
	}

	uint8_t roller=data[1];


	type=data[0];
	data+=2;
	len-=2;

	if(len<0)
	{
		mylog(log_debug,"len <0 ,%d\n",len);
		return -1;
	}

	if(roller!=conn_info.oppsite_roller)
	{
		conn_info.oppsite_roller=roller;
		conn_info.last_oppsite_roller_time=get_current_time();
	}
	conn_info.my_roller++;//increase on a successful recv


	if(after_recv_raw0(conn_info.raw_info)!=0) return -1;

	return 0;
}
int recv_safer(conn_info_t &conn_info,char &type,char* &data,int &len)///safer transfer function with anti-replay,when mutually verification is done.
{
	packet_info_t &send_info=conn_info.raw_info.send_info;
	packet_info_t &recv_info=conn_info.raw_info.recv_info;

	char * recv_data;int recv_len;
	static char recv_data_buf[buf_len];

	if(recv_raw0(conn_info.raw_info,recv_data,recv_len)!=0) return -1;

	return parse_safer(conn_info,recv_data,recv_len,type,data,len);
}