#pragma module	REDIR	"REDIR-1-B"
#define __MODULE__      "REDIR"

/*
**++
**  FACILITY:  HTTP Redirector
**		
**
**  MODULE DESCRIPTION:
**
**	This is a main module of the REDIR facility.
**
**  AUTHORS:
**
**      Ruslan R. Laishev
**
**  CREATION DATE:  12-OCT-2009
**
**  DESIGN ISSUES:
**
**
**
**  MODIFICATION HISTORY:
**
**	 1-DEC-2009	RRL	Fixed bug with skipping ARP-multicast by adding
**				NMA$C_PCLI_MLT = NMA$C_STATE_ON -- Accept all multicast addresses.
**
**      {@tbs@}...
**--
*/

/*
**
**	OpenVMS Includes
**
*/
#define __NEW_STARLET   1
#include        <descrip.h>
#include        <iodef.h>
#include        <ssdef.>
#include        <starlet.h>
#include        <stdio.h>
#include        <stdlib.h>
#include        <string.h>
#include        <stsdef.h>
#include        <iosbdef.h>
#include        <efndef.h>
#include        <nmadef.h>
#include        <lib$routines.h>
#include	<inet.h>
#include	<in.h>
#include	<cli$routines.h>
#include	<clidef.h>
#include	<climsgdef.h>
#include	<stdarg.h>
#include	<pthread.h>


/*
**	TCP/IP protocol basic definitions
*/
#include	"ipdef.h"

#include	"rdrdef.h"
#include	"redir_msg.h"

#include	"macros.h"


/*
**	Network Device name and Hawrdare Address (MAC address)
*/
struct dsc$descriptor_d	nicdsc;
ETH_MAC	hwa, broad = {.eth$b_mac = {0xff,0xff,0xff,0xff,0xff,0xff}};

IP4_ADDR	homeip,gateway;
int	ipchan,arpchan;

/*
**	CLI stuff
*/
$DESCRIPTOR(p1_dsc,	"P1");
$DESCRIPTOR(p2_dsc,	"P2");
$DESCRIPTOR(p3_dsc,	"P3");
$DESCRIPTOR(p4_dsc,	"P4");
$DESCRIPTOR(debug_dsc,	"DEBUG");
extern  void    *REDIR_CLD;


int	debug_flag = 0;
unsigned char buffer[8192],
		url[255];


#pragma nomember_alignment

struct  p_listd {
        int     len;
        void *  ptr;
        };


void	mac2str	(
	ETH_MAC *mac,
	void	*buf
		)
{
	sprintf(buf,"%02X-%02X-%02X-%02X-%02X-%02X",mac->eth$b_mac[0],mac->eth$b_mac[1],mac->eth$b_mac[2],
			mac->eth$b_mac[3],mac->eth$b_mac[4],mac->eth$b_mac[5]);
}

/*
**++
**  FUNCTIONAL DESCRIPTION:
**
**      Put formated message to standard output device (SYS$OUTPUT).
**
**  FORMAL PARAMETERS:
**
**	ctx:	A session context
**      msgid:	VMS condition code
**              variable agriments list
**
**  RETURN VALUE:
**
**      VMS condition code
**
**
**--
*/
int	_log	(
			int	msgid,
			...
			)
{
long	status,retvalue = msgid;
va_list	ap;
char	buf[4096] = {"!%D "},outadr[4],msg_buf[4096];
struct	dsc$descriptor	opr_dsc,buf_dsc,fao_dsc;
int	argc,argl[32],idx,flag=15,lvl;

	/*
	** Get a message text with given msgid
	*/
	INIT_SDESC(fao_dsc,sizeof(buf)-4,&buf[4]);
	if ( !(1 & (status =  sys$getmsg (msgid,&fao_dsc.dsc$w_length,&fao_dsc,flag,&outadr))) )
		lib$signal(status);
	
	/*
	** Reorganize parameters list for $FAOL
	*/
	va_start(ap,msgid);
	argl[0] = 0;
	for (idx = 1,va_count(argc);idx < argc;idx++)
		argl[idx] = va_arg(ap,unsigned);
        va_end((void *) msgid);

	/*
	** Format a message, put it to SYS$OUTPUT
	*/
	fao_dsc.dsc$a_pointer -=4;
	fao_dsc.dsc$w_length  +=4;
	INIT_SDESC(buf_dsc, sizeof(msg_buf),msg_buf);
	if ( !(1 & (status = sys$faol(&fao_dsc,&buf_dsc.dsc$w_length,&buf_dsc,argl))) )
		lib$signal(status);

	lib$put_output(&buf_dsc);

	return	retvalue;
}


/*
**++
**  FUNCTIONAL DESCRIPTION:
**
**      Processing command line parameters.
**
**  FORMAL PARAMETERS:
**
**      None.
**
**  RETURN VALUE:
**
**      VMS Condition code
**
**
**--
*/
int	redir	(void)
{
int	status;
char	buf[32];
struct dsc$descriptor junk;

	/*
	** /DEBUG - ?
	*/
	debug_flag = CLI$_PRESENT == cli$present (&debug_dsc);

	/*
	** P1/NICDEV - Network device name
	*/
	INIT_DDESC(nicdsc);
	if ( !(1 & (status = cli$get_value(&p1_dsc,&nicdsc,&nicdsc.dsc$w_length))) )
		return	lib$signal(status);

	/*
	** P2/Home IP address
	*/
	INIT_SDESC(junk,sizeof(buf),buf);
	if ( !(1 & (status = cli$get_value(&p2_dsc,&junk,&junk.dsc$w_length))) )
		return	lib$signal(status);
	buf[junk.dsc$w_length] = '\0';
	inet_aton(buf,&homeip);


	/*
	** P3/Default Gateway IP address
	*/
	INIT_SDESC(junk,sizeof(buf),buf);
	if ( !(1 & (status = cli$get_value(&p3_dsc,&junk,&junk.dsc$w_length))) )
		return	lib$signal(status);
	buf[junk.dsc$w_length] = '\0';
	inet_aton(buf,&gateway);


	/*
	** URL to redirect
	*/
	INIT_SDESC(junk,sizeof(url),url);
	if ( !(1 & (status = cli$get_value(&p4_dsc,&junk,&junk.dsc$w_length))) )
		return	lib$signal(status);
	if ( url[0] == '"' )
		memmove(&url,&url[1], junk.dsc$w_length -= 2);

	url[junk.dsc$w_length] = '\0';

	return	SS$_NORMAL;
}

/*
**++
**  FUNCTIONAL DESCRIPTION:
**
**      Perfroms ARP Gratuitous - ARP Announcing
**
**  FORMAL PARAMETERS:
**
**      None.
**
**  RETURN VALUE:
**
**      VMS Condition code
**
**
**--
*/
void	arp_proc	(void)
{
int     status;
IOSB    iosb;
struct {short pcli_fmt; int fmt; 
	short pcli_tpy; int pty;
	short pcli_pad; int pad;
	short pcli_mlt; int mlt; }
	arp_p = {
        NMA$C_PCLI_FMT, NMA$C_LINFM_ETH,	/* Ethernet II frame format		*/
        NMA$C_PCLI_PTY,0x0608,			/* Protocol Type is ARP			*/
	NMA$C_PCLI_PAD,NMA$C_STATE_OFF,		/* Don't prefix by length data block	*/
	NMA$C_PCLI_MLT,NMA$C_STATE_ON
        };
struct  p_listd p_dsc = {sizeof(arp_p),&arp_p};


ARP_PDU	arp,*parp = (ARP_PDU *) &buffer;
NMA_ATTR *attr = &buffer;
HDR_ETH2	ehdr;
char	tha[32],sha[32],tpa[32],spa[32];

        /*
        ** Start a channel to the NIC
        */
        if ( !(1 & (status = sys$assign(&nicdsc,&arpchan,0,0))) )
                lib$signal(status);

        if ( !(1 & (status = sys$qiow(EFN$C_ENF,arpchan,IO$_SETMODE|IO$M_CTRL|IO$M_STARTUP,
                        &iosb,0,0,0,&p_dsc,0,0,0,0)))
                || !(1 & iosb.iosb$w_status) )
                lib$signal((1 & status)?iosb.iosb$w_status:status);

	/*
	* Issue the SENSEMODE QIO to get our physical address for the ARP messages.
	*/
	p_dsc.len	= sizeof(buffer);
	p_dsc.ptr	= &buffer;
 	if ( !(1 & (status = sys$qiow(EFN$C_ENF,arpchan,IO$_SENSEMODE|IO$M_CTRL,
			&iosb,0,0,0,&p_dsc,0,0,0,0)))
		|| !(1 & iosb.iosb$w_status) )
		lib$signal((1 & status)?iosb.iosb$w_status:status);

	/*
	** Run over returned attributes list to find the NMA$C_PCLI_PHA
	*/
	for(int i = 0; i < iosb.iosb$w_bcnt; )
		{
		DEBUG("offset = %u,attr->nma$v_pid = %u\n",i,attr->nma$v_pid);

		if ( attr->nma$v_pid == NMA$C_PCLI_PHA )
			{
			memcpy(&hwa,attr->nma$b_prm,sizeof(ETH_MAC));
			break;
			}
		else	{
			if ( attr->nma$v_str )
				{
				DEBUG("attr->nma$b_prm[0:%u] = '%.*s'\n",
					attr->nma$w_bcnt,attr->nma$w_bcnt,attr->nma$b_prm);
				i += (NMA$K_STRSZ + attr->nma$w_bcnt);
				}
			else	{
				DEBUG("attr->nma$l_prm = %u/%x\n",
					attr->nma$l_prm,attr->nma$l_prm);
				i += NMA$K_LWSZ;
				}

			attr	= (NMA_ATTR *) &buffer[i];
			}
		}

	/*
	** Build ARP packet and send it to default gateway/router
	*/
	arp.arp$w_hrd	= htons(1);
	arp.arp$w_proto	= htons(PTY$K_IP);
	arp.arp$b_hln	= sizeof(ETH_MAC);
	arp.arp$b_pln	= sizeof(IP4_ADDR);
	arp.arp$w_op	= htons(ARP$K_REQUEST);
	memcpy(&arp.arp$r_tha,&broad,sizeof(ETH_MAC));
	memcpy(&arp.arp$r_tpa,&gateway,sizeof(IP4_ADDR));
	memcpy(&arp.arp$r_sha,&hwa,sizeof(ETH_MAC));
	memcpy(&arp.arp$r_spa,&homeip,sizeof(IP4_ADDR));

	if ( !(1 & (status = sys$qiow(EFN$C_ENF,arpchan,IO$_WRITEVBLK,&iosb,0,0,&arp,
        	        sizeof(ARP_PDU),0,0,&broad,0)))
                	|| !(1 & iosb.iosb$w_status) )
	                lib$signal((1 & status)?iosb.iosb$w_status:status);

	/*
	** Start listening for ARP request for the our Home IP,
	** answering with our MAC Address
	*/
	while (1)
		{
		if ( !(1 & (status = sys$qiow(EFN$C_ENF,arpchan,IO$_READVBLK,&iosb,0,0,&buffer,
        	        sizeof(buffer),0,0,&ehdr,0)))
                	|| !(1 & iosb.iosb$w_status) )
	                lib$signal((1 & status)?iosb.iosb$w_status:status);

		mac2str(&parp->arp$r_tha,tha);
		mac2str(&parp->arp$r_sha,sha);
		inet_ntop  (AF_INET,&parp->arp$r_tpa,tpa,sizeof(tpa));
		inet_ntop  (AF_INET,&parp->arp$r_spa,spa,sizeof(spa));

		_log(REDIR_RARPPKT,ntohs(parp->arp$w_op),sha,spa,tha,tpa);

		if ( parp->arp$w_op != htons(ARP$K_REQUEST) )
			continue;

		if ( memcmp(&parp->arp$r_tpa,&homeip,sizeof(IP4_ADDR)) )
			continue;
		
		/*
		** Build ARP Reply packet
		*/
		arp.arp$w_op	= htons(ARP$K_REPLY);
		memcpy(&arp.arp$r_tha,&parp->arp$r_sha,sizeof(ETH_MAC));
		memcpy(&arp.arp$r_tpa,&parp->arp$r_spa,sizeof(IP4_ADDR));

		if ( !(1 & (status = sys$qiow(EFN$C_ENF,arpchan,IO$_WRITEVBLK,&iosb,0,0,&arp,
        		        sizeof(ARP_PDU),0,0,&arp.arp$r_tha,0)))
                		|| !(1 & iosb.iosb$w_status) )
	                	lib$signal((1 & status)?iosb.iosb$w_status:status);

		mac2str(&arp.arp$r_tha,tha);
		mac2str(&arp.arp$r_sha,sha);
		inet_ntop  (AF_INET,&arp.arp$r_tpa,tpa,sizeof(tpa));
		inet_ntop  (AF_INET,&arp.arp$r_spa,spa,sizeof(spa));

		_log(REDIR_SARPPKT,ntohs(arp.arp$w_op),sha,spa,tha,tpa);
		}

	return	SS$_NORMAL;

}

unsigned short	ipchksum(
	IP_DGRAM	*ipdg,
	unsigned short	len
			)
{
unsigned short	*sdata = (unsigned short *) ipdg;
unsigned	 acc = 0;

	ipdg->ip$w_csum	= 0;

  	for (; len > 1; len -= 2)
		acc += *sdata++;

	/*
	** Add up any odd byte
	*/
	if ( len )
		acc += (unsigned short)(*(unsigned char *)sdata);

	acc = (acc >> 16) + (acc & 0xFFFF);
	acc += (acc >> 16);

	return	~acc;
}

unsigned short	tcpchksum(
	IP_DGRAM *	ipdg,
	TCP_SEG	*	seg,
	unsigned short	 len
			)
{
unsigned short	*sdata = (unsigned short *) seg;
int	acc = 0;
  
	seg->tcp$w_csum	= 0;

	/*
	** Compute TCP pseudo header check sum
	*/
	acc	+= (unsigned short) htons(ipdg->ip$b_proto);
	acc	+= (unsigned short) htons(len);

	sdata	 = (unsigned short *) &ipdg->ip$r_src;
	acc	+= *sdata++;
	acc	+= *sdata++;
	sdata	 = (unsigned short *) &ipdg->ip$r_dst;
	acc	+= *sdata++;
	acc	+= *sdata++;

  	for ( sdata = (unsigned short *) seg; len > 1; len -= 2)
		acc += *sdata++;

	/*
	** add up any odd byte
	*/
	if ( len )
		acc += (unsigned short)(*(unsigned char *)sdata);

	/*
	** DISK$SYSMAN:[V82.LAN.LIS]LANACP_DLL.LIS, in_chksum()
	*/
	acc = (acc >> 16) + (acc & 0xFFFF);
	acc += (acc >> 16);


	return	~acc;
}


void    main    (void)
{
unsigned status = 0,seq = 0;
IOSB    iosb;
HDR_ETH2	ehdr,outehdr;
IP_DGRAM *	ipdg = (IP_DGRAM *) &buffer;
TCP_SEG	*	seg = &ipdg->ip$r_seg;
unsigned char	hthead [] ={"HTTP/1.1 307 Temporary redirect\r\n"\
			"Location: %s\r\n"\
			"Content-Type: text/html\r\n"\
			"Content-Length: %u\r\n\r\n%s"},
		htbody [] ={"<html><head><title>OpenVMS forever !!! StarLet Team</title></head>"\
			"<body></body></html>"};

struct {short pcli_fmt; int fmt; 
	short pcli_tpy; int pty;
	short pcli_pad; int pad;}
	ip_p = {
        NMA$C_PCLI_FMT, NMA$C_LINFM_ETH,	/* Ethernet II frame format		*/
        NMA$C_PCLI_PTY,0x0008,			/* Protocol Type is IP			*/
	NMA$C_PCLI_PAD,NMA$C_STATE_OFF		/* Don't prefix by length data block	*/
        };
struct  p_listd p_dsc = {sizeof(ip_p),&ip_p};

char    buf[255] = {"REDIR "};
struct dsc$descriptor cmd_dsc;

pthread_t       tid;
pthread_attr_t  tattr;

        /*
        ** Initalize attributes for threads
        */
        status = pthread_attr_init(&tattr);
        status = pthread_attr_setdetachstate(&tattr,PTHREAD_CREATE_JOINABLE);
        status = pthread_attr_setstacksize(&tattr,128000);

	/*
	** Process command line arguments
	*/
	INIT_SDESC(cmd_dsc,sizeof(buf)-6,buf+6);
	if ( !(1 & (status = lib$get_foreign(&cmd_dsc,0,&cmd_dsc.dsc$w_length,&status))) )
		return status;

        cmd_dsc.dsc$w_length    += 6;
        cmd_dsc.dsc$a_pointer   -= 6;

        if ( CLI$_NORMAL == (status = cli$dcl_parse (&cmd_dsc,&REDIR_CLD,0,0,0)) )
		status = cli$dispatch();

	if ( !(1 & status) )
		sys$exit(status);


	_log(REDIR_HOMEIP,homeip.ip4$b_addr[0],homeip.ip4$b_addr[1],
			homeip.ip4$b_addr[2],homeip.ip4$b_addr[3]);
	_log(REDIR_URL,url);

//	arp_proc();


	if ( status = pthread_create(&tid,&tattr,(void *)arp_proc,NULL) )
		perror("thread");

	sleep(1);

	_log(REDIR_NICDEV,&nicdsc,hwa.eth$b_mac[0],hwa.eth$b_mac[1],hwa.eth$b_mac[2],
			hwa.eth$b_mac[3],hwa.eth$b_mac[4],hwa.eth$b_mac[5]);

        /*
        ** Start a channel to the NIC
        */
        if ( !(1 & (status = sys$assign(&nicdsc,&ipchan,0,0))) )
                lib$signal(status);

        if ( !(1 & (status = sys$qiow(EFN$C_ENF,ipchan,IO$_SETMODE|IO$M_CTRL|IO$M_STARTUP,
                        &iosb,0,0,0,&p_dsc,0,0,0,0)))
                || !(1 & iosb.iosb$w_status) )
                lib$signal((1 & status)?iosb.iosb$w_status:status);

	/*
	**
	*/
	for(int i = 0;; i++)
		{
		if ( !(1 & (status = sys$qiow(EFN$C_ENF,ipchan,IO$_READVBLK,&iosb,0,0,&buffer,
        	        sizeof(buffer),0,0,&ehdr,0)))
                	|| !(1 & iosb.iosb$w_status) )
	                lib$signal((1 & status)?iosb.iosb$w_status:status);

		{
		char	src[16],dst[16];
		inet_ntop  (AF_INET,&ipdg->ip$r_dst,dst,sizeof(dst));
		inet_ntop  (AF_INET,&ipdg->ip$r_src,src,sizeof(src));

		_log(REDIR_RCVD,src,ntohs(seg->tcp$w_spn),
				dst,ntohs(seg->tcp$w_dpn),
				iosb.iosb$w_bcnt,
				ntohl(seg->tcp$l_seq),
				ntohl(seg->tcp$l_ack));
		}

		/*
		** Got SYN...
		*/
		status		= ipdg->ip$r_src.ip4$l_addr;
		ipdg->ip$r_src.ip4$l_addr = ipdg->ip$r_dst.ip4$l_addr;
		ipdg->ip$r_dst.ip4$l_addr = status;

                status		= seg->tcp$w_spn;
		seg->tcp$w_spn	= seg->tcp$w_dpn;
		seg->tcp$w_dpn	= status;

		seg->tcp$v_hlen	= TCP$K_SZ/4;


		
		status		= seg->tcp$l_ack;
                seg->tcp$l_ack	= htonl(1 + ntohl(seg->tcp$l_seq));
		seg->tcp$l_seq	= status;

		if ( seg->tcp$v_syn )
			{
			seg->tcp$b_ctl	|= (TCP$M_ACK | TCP$M_PSH);

			status = sprintf(&seg->tcp$b_data,&hthead,url,sizeof(htbody)-1,htbody);
			ipdg->ip$w_len	= htons(TCP$K_SZ + IP$K_SZ + status);
			seg->tcp$l_seq	= 0;

			seq =  status;
			}
		else	{
			seg->tcp$b_ctl	= (TCP$M_RST | TCP$M_FIN | TCP$M_ACK);
			ipdg->ip$w_len	= htons(TCP$K_SZ + IP$K_SZ);
//			seg->tcp$l_seq	= htonl(seq);
			}

		/*
		** Calculate check sums and send
		*/
                ipdg->ip$w_csum = ipchksum(ipdg,ipdg->ip$v_hlen*4);
                seg->tcp$w_csum = tcpchksum(ipdg,seg,ntohs(ipdg->ip$w_len) - ipdg->ip$v_hlen*4);

		if ( !(1 & (status = sys$qiow(EFN$C_ENF,ipchan,IO$_WRITEVBLK,&iosb,0,0,ipdg,
			ntohs(ipdg->ip$w_len),0,0,&ehdr.eth2$r_sa,0)))
                	|| !(1 & iosb.iosb$w_status) )
	                lib$signal((1 & status)?iosb.iosb$w_status:status);

		{
		char	src[16],dst[16];
		inet_ntop  (AF_INET,&ipdg->ip$r_dst,dst,sizeof(dst));
		inet_ntop  (AF_INET,&ipdg->ip$r_src,src,sizeof(src));

		_log(REDIR_SENT,src,ntohs(seg->tcp$w_spn),
				dst,ntohs(seg->tcp$w_dpn),
				iosb.iosb$w_bcnt,
				ntohl(seg->tcp$l_seq),
				ntohl(seg->tcp$l_ack));
		}

		}
}