//
// libtgvoip is free and unencumbered public domain software.
// For more information, see http://unlicense.org or the UNLICENSE file
// you should have received with this source code distribution.
//

#include "NetworkSocketPosix.h"
#include <sys/socket.h>
#include <errno.h>
#include <assert.h>
#include <netdb.h>
#include <net/if.h>
#include <sys/ioctl.h>
#include <unistd.h>
#include <netinet/tcp.h>
#include "../../logging.h"
#include "../../VoIPController.h"
#include "../../BufferInputStream.h"
#include "../../BufferOutputStream.h"

using namespace tgvoip;


NetworkSocketPosix::NetworkSocketPosix(NetworkProtocol protocol) : NetworkSocket(protocol), lastRecvdV4(0), lastRecvdV6("::0"){
	needUpdateNat64Prefix=true;
	nat64Present=false;
	switchToV6at=0;
	isV4Available=false;
    fd=-1;
	useTCP=false;
	closing=false;

	tcpConnectedAddress=NULL;
	tcpConnectedPort=0;
}

NetworkSocketPosix::~NetworkSocketPosix(){
	if(tcpConnectedAddress)
		delete tcpConnectedAddress;
}

void NetworkSocketPosix::SetMaxPriority(){
#ifdef __APPLE__
	int prio=NET_SERVICE_TYPE_VO;
	int res=setsockopt(fd, SOL_SOCKET, SO_NET_SERVICE_TYPE, &prio, sizeof(prio));
	if(res<0){
		LOGE("error setting darwin-specific net priority: %d / %s", errno, strerror(errno));
	}
#else
	int prio=5;
	int res=setsockopt(fd, SOL_SOCKET, SO_PRIORITY, &prio, sizeof(prio));
	if(res<0){
		LOGE("error setting priority: %d / %s", errno, strerror(errno));
	}
	prio=6 << 5;
	res=setsockopt(fd, SOL_IP, IP_TOS, &prio, sizeof(prio));
	if(res<0){
		LOGE("error setting ip tos: %d / %s", errno, strerror(errno));
	}
#endif
}

void NetworkSocketPosix::Send(NetworkPacket *packet){
	if(!packet || !packet->address){
		LOGW("tried to send null packet");
		return;
	}
	int res;
	if(protocol==PROTO_UDP){
		sockaddr_in6 addr;
		IPv4Address *v4addr=dynamic_cast<IPv4Address *>(packet->address);
		if(v4addr){
			if(needUpdateNat64Prefix && !isV4Available && VoIPController::GetCurrentTime()>switchToV6at && switchToV6at!=0){
				LOGV("Updating NAT64 prefix");
				nat64Present=false;
				addrinfo *addr0;
				int res=getaddrinfo("ipv4only.arpa", NULL, NULL, &addr0);
				if(res!=0){
					LOGW("Error updating NAT64 prefix: %d / %s", res, gai_strerror(res));
				}else{
					addrinfo *addrPtr;
					unsigned char *addr170=NULL;
					unsigned char *addr171=NULL;
					for(addrPtr=addr0; addrPtr; addrPtr=addrPtr->ai_next){
						if(addrPtr->ai_family==AF_INET6){
							sockaddr_in6 *translatedAddr=(sockaddr_in6 *) addrPtr->ai_addr;
							uint32_t v4part=*((uint32_t *) &translatedAddr->sin6_addr.s6_addr[12]);
							if(v4part==0xAA0000C0 && !addr170){
								addr170=translatedAddr->sin6_addr.s6_addr;
							}
							if(v4part==0xAB0000C0 && !addr171){
								addr171=translatedAddr->sin6_addr.s6_addr;
							}
							char buf[INET6_ADDRSTRLEN];
							LOGV("Got translated address: %s", inet_ntop(AF_INET6, &translatedAddr->sin6_addr, buf, sizeof(buf)));
						}
					}
					if(addr170 && addr171 && memcmp(addr170, addr171, 12)==0){
						nat64Present=true;
						memcpy(nat64Prefix, addr170, 12);
						char buf[INET6_ADDRSTRLEN];
						LOGV("Found nat64 prefix from %s", inet_ntop(AF_INET6, addr170, buf, sizeof(buf)));
					}else{
						LOGV("Didn't find nat64");
					}
					freeaddrinfo(addr0);
				}
				needUpdateNat64Prefix=false;
			}
			memset(&addr, 0, sizeof(sockaddr_in6));
			addr.sin6_family=AF_INET6;
			*((uint32_t *) &addr.sin6_addr.s6_addr[12])=v4addr->GetAddress();
			if(nat64Present)
				memcpy(addr.sin6_addr.s6_addr, nat64Prefix, 12);
			else
				addr.sin6_addr.s6_addr[11]=addr.sin6_addr.s6_addr[10]=0xFF;

		}else{
			IPv6Address *v6addr=dynamic_cast<IPv6Address *>(packet->address);
			assert(v6addr!=NULL);
			memcpy(addr.sin6_addr.s6_addr, v6addr->GetAddress(), 16);
		}
		addr.sin6_port=htons(packet->port);
		res=sendto(fd, packet->data, packet->length, 0, (const sockaddr *) &addr, sizeof(addr));
	}else{
		res=send(fd, packet->data, packet->length, 0);
	}
	if(res<0){
		LOGE("error sending: %d / %s", errno, strerror(errno));
		if(errno==ENETUNREACH && !isV4Available && VoIPController::GetCurrentTime()<switchToV6at){
			switchToV6at=VoIPController::GetCurrentTime();
			LOGI("Network unreachable, trying NAT64");
		}
	}
}

void NetworkSocketPosix::Receive(NetworkPacket *packet){
	if(protocol==PROTO_UDP){
		int addrLen=sizeof(sockaddr_in6);
		sockaddr_in6 srcAddr;
		ssize_t len=recvfrom(fd, packet->data, packet->length, 0, (sockaddr *) &srcAddr, (socklen_t *) &addrLen);
		if(len>0)
			packet->length=(size_t) len;
		else{
			LOGE("error receiving %d / %s", errno, strerror(errno));
			packet->length=0;
			return;
		}
		//LOGV("Received %d bytes from %s:%d at %.5lf", len, inet_ntoa(srcAddr.sin_addr), ntohs(srcAddr.sin_port), GetCurrentTime());
		if(!isV4Available && IN6_IS_ADDR_V4MAPPED(&srcAddr.sin6_addr)){
			isV4Available=true;
			LOGI("Detected IPv4 connectivity, will not try IPv6");
		}
		if(IN6_IS_ADDR_V4MAPPED(&srcAddr.sin6_addr) || (nat64Present && memcmp(nat64Prefix, srcAddr.sin6_addr.s6_addr, 12)==0)){
			in_addr v4addr=*((in_addr *) &srcAddr.sin6_addr.s6_addr[12]);
			lastRecvdV4=IPv4Address(v4addr.s_addr);
			packet->address=&lastRecvdV4;
		}else{
			lastRecvdV6=IPv6Address(srcAddr.sin6_addr.s6_addr);
			packet->address=&lastRecvdV6;
		}
		packet->protocol=PROTO_UDP;
		packet->port=ntohs(srcAddr.sin6_port);
	}else if(protocol==PROTO_TCP){
		int res=recv(fd, packet->data, packet->length, 0);
		if(res<=0){
			LOGE("Error receiving from TCP socket: %d / %s", errno, strerror(errno));
			failed=true;
		}else{
			packet->length=(size_t)res;
			packet->address=tcpConnectedAddress;
			packet->port=tcpConnectedPort;
			packet->protocol=PROTO_TCP;
		}
	}
}

void NetworkSocketPosix::Open(){
	if(protocol!=PROTO_UDP)
		return;
	fd=socket(PF_INET6, SOCK_DGRAM, IPPROTO_UDP);
	if(fd<0){
		LOGE("error creating socket: %d / %s", errno, strerror(errno));
		failed=true;
		return;
	}
	int flag=0;
	int res=setsockopt(fd, IPPROTO_IPV6, IPV6_V6ONLY, &flag, sizeof(flag));
	if(res<0){
		LOGE("error enabling dual stack socket: %d / %s", errno, strerror(errno));
		failed=true;
		return;
	}

	SetMaxPriority();

	int tries=0;
	sockaddr_in6 addr;
	//addr.sin6_addr.s_addr=0;
	memset(&addr, 0, sizeof(sockaddr_in6));
	//addr.sin6_len=sizeof(sa_family_t);
	addr.sin6_family=AF_INET6;
	for(tries=0;tries<10;tries++){
		addr.sin6_port=htons(GenerateLocalPort());
		res=::bind(fd, (sockaddr *) &addr, sizeof(sockaddr_in6));
		LOGV("trying bind to port %u", ntohs(addr.sin6_port));
		if(res<0){
			LOGE("error binding to port %u: %d / %s", ntohs(addr.sin6_port), errno, strerror(errno));
		}else{
			break;
		}
	}
	if(tries==10){
		addr.sin6_port=0;
		res=::bind(fd, (sockaddr *) &addr, sizeof(sockaddr_in6));
		if(res<0){
			LOGE("error binding to port %u: %d / %s", ntohs(addr.sin6_port), errno, strerror(errno));
			//SetState(STATE_FAILED);
			failed=true;
			return;
		}
	}
	size_t addrLen=sizeof(sockaddr_in6);
	getsockname(fd, (sockaddr*)&addr, (socklen_t*) &addrLen);
	uint16_t localUdpPort=ntohs(addr.sin6_port);
	LOGD("Bound to local UDP port %u", ntohs(addr.sin6_port));

	needUpdateNat64Prefix=true;
	isV4Available=false;
	switchToV6at=VoIPController::GetCurrentTime()+ipv6Timeout;
}

void NetworkSocketPosix::Close(){
	closing=true;
	failed=true;
	
    if (fd>=0) {
        shutdown(fd, SHUT_RDWR);
        close(fd);
    }
}

void NetworkSocketPosix::Connect(NetworkAddress *address, uint16_t port){
	IPv4Address* v4addr=dynamic_cast<IPv4Address*>(address);
	IPv6Address* v6addr=dynamic_cast<IPv6Address*>(address);
	sockaddr_in v4;
	sockaddr_in6 v6;
	sockaddr* addr=NULL;
	size_t addrLen=0;
	if(v4addr){
		v4.sin_family=AF_INET;
		v4.sin_addr.s_addr=v4addr->GetAddress();
		v4.sin_port=htons(port);
		addr=reinterpret_cast<sockaddr*>(&v4);
		addrLen=sizeof(v4);
	}else if(v6addr){
		v6.sin6_family=AF_INET6;
		memcpy(v6.sin6_addr.s6_addr, v6addr->GetAddress(), 16);
		v6.sin6_flowinfo=0;
		v6.sin6_scope_id=0;
		v6.sin6_port=htons(port);
		addr=reinterpret_cast<sockaddr*>(&v6);
		addrLen=sizeof(v6);
	}else{
		LOGE("Unknown address type in TCP connect");
		failed=true;
		return;
	}
	fd=socket(addr->sa_family, SOCK_STREAM, IPPROTO_TCP);
	if(fd<0){
		LOGE("Error creating TCP socket: %d / %s", errno, strerror(errno));
		failed=true;
		return;
	}
	int opt=1;
	setsockopt(fd, IPPROTO_TCP, TCP_NODELAY, &opt, sizeof(opt));
	timeval timeout;
	timeout.tv_sec=5;
	timeout.tv_usec=0;
	setsockopt(fd, SOL_SOCKET, SO_SNDTIMEO, &timeout, sizeof(timeout));
	timeout.tv_sec=60;
	setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, &timeout, sizeof(timeout));
	int res=connect(fd, (const sockaddr*) addr, addrLen);
	if(res!=0){
		LOGW("error connecting TCP socket to %s:%u: %d / %s; %d / %s", address->ToString().c_str(), port, res, strerror(res), errno, strerror(errno));
		close(fd);
		failed=true;
		return;
	}
	tcpConnectedAddress=v4addr ? (NetworkAddress*)new IPv4Address(*v4addr) : (NetworkAddress*)new IPv6Address(*v6addr);
	tcpConnectedPort=port;
	LOGI("successfully connected to %s:%d", tcpConnectedAddress->ToString().c_str(), tcpConnectedPort);
}

void NetworkSocketPosix::OnActiveInterfaceChanged(){
	needUpdateNat64Prefix=true;
	isV4Available=false;
	switchToV6at=VoIPController::GetCurrentTime()+ipv6Timeout;
}

std::string NetworkSocketPosix::GetLocalInterfaceInfo(IPv4Address *v4addr, IPv6Address *v6addr){
	struct ifconf ifc;
	struct ifreq* ifr;
	char buf[16384];
	int sd;
	std::string name="";
	sd=socket(PF_INET, SOCK_DGRAM, 0);
	if(sd>0){
		ifc.ifc_len=sizeof(buf);
		ifc.ifc_ifcu.ifcu_buf=buf;
		if(ioctl(sd, SIOCGIFCONF, &ifc)==0){
			ifr=ifc.ifc_req;
			int len;
			int i;
			for(i=0;i<ifc.ifc_len;){
#ifndef __linux__
				len=IFNAMSIZ + ifr->ifr_addr.sa_len;
#else
				len=sizeof(*ifr);
#endif
				if(ifr->ifr_addr.sa_family==AF_INET){
					if(ioctl(sd, SIOCGIFADDR, ifr)==0){
						struct sockaddr_in* addr=(struct sockaddr_in *)(&ifr->ifr_addr);
						LOGI("Interface %s, address %s\n", ifr->ifr_name, inet_ntoa(addr->sin_addr));
						if(ioctl(sd, SIOCGIFFLAGS, ifr)==0){
							if(!(ifr->ifr_flags & IFF_LOOPBACK) && (ifr->ifr_flags & IFF_UP) && (ifr->ifr_flags & IFF_RUNNING)){
								//LOGV("flags = %08X", ifr->ifr_flags);
								if((ntohl(addr->sin_addr.s_addr) & 0xFFFF0000)==0xA9FE0000){
									LOGV("skipping link-local");
									continue;
								}
								if(v4addr){
									*v4addr=IPv4Address(addr->sin_addr.s_addr);
								}
								name=ifr->ifr_name;
							}
						}
					}else{
						LOGE("Error getting address for %s: %d\n", ifr->ifr_name, errno);
					}
				}
				ifr=(struct ifreq*)((char*)ifr+len);
				i+=len;
			}
		}else{
			LOGE("Error getting LAN address: %d", errno);
		}
	}
	close(sd);
	return name;
}

uint16_t NetworkSocketPosix::GetLocalPort(){
	sockaddr_in6 addr;
	size_t addrLen=sizeof(sockaddr_in6);
	getsockname(fd, (sockaddr*)&addr, (socklen_t*) &addrLen);
	return ntohs(addr.sin6_port);
}

std::string NetworkSocketPosix::V4AddressToString(uint32_t address){
	char buf[INET_ADDRSTRLEN];
	in_addr addr;
	addr.s_addr=address;
	inet_ntop(AF_INET, &addr, buf, sizeof(buf));
	return std::string(buf);
}

std::string NetworkSocketPosix::V6AddressToString(unsigned char *address){
	char buf[INET6_ADDRSTRLEN];
	in6_addr addr;
	memcpy(addr.s6_addr, address, 16);
	inet_ntop(AF_INET6, &addr, buf, sizeof(buf));
	return std::string(buf);
}

uint32_t NetworkSocketPosix::StringToV4Address(std::string address){
	in_addr addr;
	inet_pton(AF_INET, address.c_str(), &addr);
	return addr.s_addr;
}

void NetworkSocketPosix::StringToV6Address(std::string address, unsigned char *out){
	in6_addr addr;
	inet_pton(AF_INET6, address.c_str(), &addr);
	memcpy(out, addr.s6_addr, 16);
}

IPv4Address *NetworkSocketPosix::ResolveDomainName(std::string name){
	addrinfo* addr0;
	IPv4Address* ret=NULL;
	int res=getaddrinfo(name.c_str(), NULL, NULL, &addr0);
	if(res!=0){
		LOGW("Error updating NAT64 prefix: %d / %s", res, gai_strerror(res));
	}else{
		addrinfo* addrPtr;
		for(addrPtr=addr0;addrPtr;addrPtr=addrPtr->ai_next){
			if(addrPtr->ai_family==AF_INET){
				sockaddr_in* addr=(sockaddr_in*)addrPtr->ai_addr;
				ret=new IPv4Address(addr->sin_addr.s_addr);
				break;
			}
		}
		freeaddrinfo(addr0);
	}
	return ret;
}

NetworkAddress *NetworkSocketPosix::GetConnectedAddress(){
	return tcpConnectedAddress;
}

uint16_t NetworkSocketPosix::GetConnectedPort(){
	return tcpConnectedPort;
}

void NetworkSocketPosix::SetTimeouts(int sendTimeout, int recvTimeout){
	timeval timeout;
	timeout.tv_sec=sendTimeout;
	timeout.tv_usec=0;
	setsockopt(fd, SOL_SOCKET, SO_SNDTIMEO, &timeout, sizeof(timeout));
	timeout.tv_sec=recvTimeout;
	setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, &timeout, sizeof(timeout));
}

bool NetworkSocketPosix::Select(std::vector<NetworkSocket *> &readFds, std::vector<NetworkSocket *> &errorFds, SocketSelectCanceller* _canceller){
	fd_set readSet;
	fd_set errorSet;
	FD_ZERO(&readSet);
	FD_ZERO(&errorSet);
	SocketSelectCancellerPosix* canceller=dynamic_cast<SocketSelectCancellerPosix*>(_canceller);
	if(canceller)
		FD_SET(canceller->pipeRead, &readSet);

	int maxfd=canceller ? canceller->pipeRead : 0;

	for(std::vector<NetworkSocket*>::iterator itr=readFds.begin();itr!=readFds.end();++itr){
		int sfd=GetDescriptorFromSocket(*itr);
		if(sfd==0){
			LOGW("can't select on one of sockets because it's not a NetworkSocketPosix instance");
			continue;
		}
		FD_SET(sfd, &readSet);
		if(maxfd<sfd)
			maxfd=sfd;
	}

	bool anyFailed=false;

	for(std::vector<NetworkSocket*>::iterator itr=errorFds.begin();itr!=errorFds.end();++itr){
		int sfd=GetDescriptorFromSocket(*itr);
		if(sfd==0){
			LOGW("can't select on one of sockets because it's not a NetworkSocketPosix instance");
			continue;
		}
		anyFailed |= (*itr)->IsFailed();
		FD_SET(sfd, &errorSet);
		if(maxfd<sfd)
			maxfd=sfd;
	}

	int res=select(maxfd+1, &readSet, NULL, &errorSet, NULL);

	if(canceller && FD_ISSET(canceller->pipeRead, &readSet) && !anyFailed){
		char c;
		read(canceller->pipeRead, &c, 1);
		return false;
	}else if(anyFailed){
		FD_ZERO(&readSet);
		FD_ZERO(&errorSet);
	}

	std::vector<NetworkSocket*>::iterator itr=readFds.begin();
	while(itr!=readFds.end()){
		int sfd=GetDescriptorFromSocket(*itr);
		if(sfd==0 || !FD_ISSET(sfd, &readSet)){
			itr=readFds.erase(itr);
		}else{
			++itr;
		}
	}

	itr=errorFds.begin();
	while(itr!=errorFds.end()){
		int sfd=GetDescriptorFromSocket(*itr);
		if((sfd==0 || !FD_ISSET(sfd, &errorSet)) && !(*itr)->IsFailed()){
			itr=errorFds.erase(itr);
		}else{
			++itr;
		}
	}
	//LOGV("select fds left: read=%d, error=%d", readFds.size(), errorFds.size());

	return readFds.size()>0 || errorFds.size()>0;
}

SocketSelectCancellerPosix::SocketSelectCancellerPosix(){
	int p[2];
	int pipeRes=pipe(p);
	assert(pipeRes==0);
	pipeRead=p[0];
	pipeWrite=p[1];
}

SocketSelectCancellerPosix::~SocketSelectCancellerPosix(){
	close(pipeRead);
	close(pipeWrite);
}

void SocketSelectCancellerPosix::CancelSelect(){
	char c=1;
	write(pipeWrite, &c, 1);
}

int NetworkSocketPosix::GetDescriptorFromSocket(NetworkSocket *socket){
	NetworkSocketPosix* sp=dynamic_cast<NetworkSocketPosix*>(socket);
	if(sp)
		return sp->fd;
	NetworkSocketWrapper* sw=dynamic_cast<NetworkSocketWrapper*>(socket);
	if(sw)
		return GetDescriptorFromSocket(sw->GetWrapped());
	return 0;
}