/******************************************************************************
    (c) 2002-2008      Christine Caulfield          christine.caulfield@googlemail.com

    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
    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.
    ******************************************************************************
    */

#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <unistd.h>
#include <signal.h>
#include <stdlib.h>
#include <ctype.h>
#include <termios.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <sys/types.h>
#include <sys/time.h>
#include <sys/fcntl.h>
#include <netdnet/dn.h>
#include <netdnet/dnetdb.h>
#include "dn_endian.h"
#include "dnlogin.h"

// If we don't have MSG_NOSIGNAL, ignore it for now
// TODO: is this correct to just ignore it?
#ifndef MSG_NOSIGNAL
#define MSG_NOSIGNAL 0
#endif

/* Foundation services messages */
#define FOUND_MSG_BIND        1
#define FOUND_MSG_UNBIND      2
#define FOUND_MSG_BINDACCEPT  4
#define FOUND_MSG_ENTERMODE   5
#define FOUND_MSG_EXITMODE    6
#define FOUND_MSG_CONFIRMMODE 7
#define FOUND_MSG_NOMODE      8
#define FOUND_MSG_COMMONDATA  9
#define FOUND_MSG_MODEDATA   10


static const char *hosttype[] = {
	"RT-11",
	"RSTS/E",
	"RSX-11S",
	"RSX-11M",
	"RSX-11D",
	"IAS",
	"VMS",
	"TOPS-20",
	"TOPS-10",
	"OS8",
	"RTS-8",
	"RSX-11M+",
	"DEC Unix", "??14", "??15", "??16", "??17",
	"Ultrix-32",
	"", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "",
	"", "",
	"", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "",
	"", "",
	"", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "",
	"", "",
	"", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "",
	"", "",
	"", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "",
	"", "",
	"", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "",
	"", "",
	"", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "",
	"", "",
	"", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "",
	"", "",
	"", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "",
	"Unix-dni"
};


/* Header for a single-message "common data" message */
struct common_header
{
	char msg;
	char pad;
	unsigned short len;
};


static int sockfd = -1;
static int (*terminal_processor)(char *, int);

static int send_bindaccept(void)
{
	int wrote;
	char bindacc_msg[] =
		{
			FOUND_MSG_BINDACCEPT,
			2,4,0,  /* Version triplet */
			7,0,    /* OS = VMS */
			0x10,   /* We talk terminal protocol */
			0,      /* Empty rev string */
		};

	wrote = write(sockfd, bindacc_msg, sizeof(bindacc_msg));
	if (wrote != sizeof(bindacc_msg))
	{
		fprintf(stderr, "%s\n", found_connerror());
		return -1;
	}
	return 0;
}


int found_getsockfd()
{
	return sockfd;
}

/* Write "Common data" with a foundation header */
int found_common_write(char *buf, int len)
{
	struct iovec vectors[2];
	struct msghdr msg;
	struct common_header header;

	DEBUG_FOUND("sending %d bytes\n", len);
	if (debug & DEBUG_FLAG_FOUND2)
	{
		int i;
		DEBUG_FOUND2("sending: ");
		for (i=0; i<len; i++)
			DEBUGLOG(DEBUG_FLAG_FOUND2, "%02x  ", (char)buf[i]);
		DEBUGLOG(DEBUG_FLAG_FOUND2, "\n\n");
	}


	memset(&msg, 0, sizeof(msg));
	vectors[0].iov_base = (void *)&header;
	vectors[0].iov_len  = sizeof(header);
	vectors[1].iov_base = buf;
	vectors[1].iov_len  = len;

	msg.msg_name    = NULL;
	msg.msg_namelen = 0;
	msg.msg_iovlen  = 2;
	msg.msg_iov     = vectors;
	msg.msg_flags   = 0;

	header.msg = FOUND_MSG_COMMONDATA;
	header.pad = 0;
	header.len = dn_htons(len);

	DEBUG_FOUND("sending common message %d bytes:\n", len);

	return sendmsg(sockfd, &msg, MSG_EOR);
}

int found_read()
{
	int len;
	char inbuf[1024];

	if ( (len=dnet_recv(sockfd, inbuf, sizeof(inbuf), MSG_EOR|MSG_DONTWAIT|MSG_NOSIGNAL)) <= 0)

	{
		if (len == -1 && (errno == EAGAIN || errno == ESPIPE))
			return 0;
		/* Remote end shut down */
		if (len == 0)
			return -1;
		if (len == -1 && errno == EPIPE) /* Old kernel bug */
			return -1;

		if (len < 0 && errno != EINVAL)/* Shurely shome mishtake */
			fprintf(stderr, "%s\n", strerror(errno));
		return -1;
	}

	DEBUG_FOUND("got message %d bytes:\n", len);
	if (debug & DEBUG_FLAG_FOUND2)
	{
		int i;

		DEBUG_FOUND2("read: ");
		for (i=0; i<len; i++)
			DEBUGLOG(DEBUG_FLAG_FOUND2,  "%02x  ", (char)inbuf[i]);
		DEBUGLOG(DEBUG_FLAG_FOUND2, "\n\n");
	}


	/* Dispatch foundation messages */
	switch (inbuf[0])
	{
	case FOUND_MSG_BIND:
		DEBUG_FOUND("connected to %s host\n", hosttype[inbuf[4]-1]);
		return send_bindaccept();

	case FOUND_MSG_UNBIND:
		DEBUG_FOUND("Unbind from host. reason = %d\n", inbuf[1]);
		return -1;

	case FOUND_MSG_ENTERMODE:
        {
		char nomode_msg[] = {0x8};
		DEBUG_FOUND("Request to enter mode = %d\n", inbuf[1]);
		write(sockfd, nomode_msg, sizeof(nomode_msg));
		return 0;
	}

	/* Common data goes straight to the terminal processor */
	case FOUND_MSG_COMMONDATA:
        {
		int ptr = 2;
		while (ptr < len)
		{
			int msglen = inbuf[ptr] | inbuf[ptr+1]<<8;

			DEBUG_FOUND("commondata: %d bytes\n",msglen);

			ptr += 2;
			terminal_processor(inbuf+ptr, msglen);
			ptr += msglen;
		}
	}
	break;

	case 3: /* Reserved */
		break;

	default:
		fprintf(stderr, "Unknown foundation services message %d received\n",
			inbuf[0]);
	}
	return 0;
}

/* Open the DECnet connection */
int found_setup_link(char *node, int object, int (*processor)(char *, int), 
		     int connect_timeout)
{
	struct nodeent *np;
	struct sockaddr_dn sockaddr;
	struct accessdata_dn accessdata;
	char *local_user;
	struct timeval timeout = {connect_timeout,0};

	if ( (np=getnodebyname(node)) == NULL)
	{
		printf("Unknown node name %s\n",node);
		return -1;
	}


	if ((sockfd = socket(AF_DECnet, SOCK_SEQPACKET, DNPROTO_NSP)) == -1)
	{
		perror("socket");
		return -1;
	}

	if (setsockopt(sockfd, SOL_SOCKET, SO_SNDTIMEO, &timeout, sizeof(timeout)))
		perror("setting snd timeout");

        /* Send the logged in userID for niceness sake */
	memset(&accessdata, 0, sizeof(accessdata));
	local_user = cuserid(NULL);
	if (!local_user || local_user == (char *)0xffffffff)
		local_user = getenv("LOGNAME");

	if (!local_user) local_user = getenv("USER");
	if (local_user)
	{
		strcpy((char *)accessdata.acc_acc, local_user);
		accessdata.acc_accl = strlen((char *)accessdata.acc_acc);
		setsockopt(sockfd, DNPROTO_NSP, SO_CONACCESS, &accessdata,
			   sizeof(accessdata));
	}

	sockaddr.sdn_family = AF_DECnet;
	sockaddr.sdn_flags = 0x00;
	sockaddr.sdn_objnum = object;

	sockaddr.sdn_objnamel = 0x00;
	sockaddr.sdn_add.a_len = 0x02;

	memcpy(sockaddr.sdn_add.a_addr, np->n_addr, 2);

	if (connect(sockfd, (struct sockaddr *) &sockaddr, sizeof(sockaddr)) < 0)
	{
		fprintf(stderr, "Cannot connect to %s: %s\n", node, found_connerror());
		return -1;
	}

	terminal_processor = processor;
	return 0;
}


/* Return the text of a connection error */
char *found_connerror()
{
	int saved_errno = errno;
#ifdef DSO_DISDATA
	struct optdata_dn optdata;
	unsigned int len = sizeof(optdata);
	char *msg;

	if (errno == ETIMEDOUT ||
	    getsockopt(sockfd, DNPROTO_NSP, DSO_CONDATA, &optdata, &len) == -1)
	{
		return strerror(saved_errno);
	}

	// Turn the rejection reason into text
	switch (optdata.opt_status)
	{
	case DNSTAT_REJECTED: msg="Rejected by object";
		break;
	case DNSTAT_RESOURCES: msg="No resources available";
		break;
	case DNSTAT_NODENAME: msg="Unrecognised node name";
		break;
	case DNSTAT_LOCNODESHUT: msg="Local Node is shut down";
		break;
	case DNSTAT_OBJECT: msg="Unrecognised object";
		break;
	case DNSTAT_OBJNAMEFORMAT: msg="Invalid object name format";
		break;
	case DNSTAT_TOOBUSY: msg="Object too busy";
		break;
	case DNSTAT_NODENAMEFORMAT: msg="Invalid node name format";
		break;
	case DNSTAT_REMNODESHUT: msg="Remote Node is shut down";
		break;
	case DNSTAT_ACCCONTROL: msg="Login information invalid at remote node";
		break;
	case DNSTAT_NORESPONSE: msg="No response from object";
		break;
	case DNSTAT_NODEUNREACH: msg="Node Unreachable";
		break;
	case DNSTAT_MANAGEMENT: msg="Abort by management/third party";
		break;
	case DNSTAT_ABORTOBJECT: msg="Remote object aborted the link";
		break;
	case DNSTAT_NODERESOURCES: msg="Node does not have sufficient resources for a new link";
		break;
	case DNSTAT_OBJRESOURCES: msg="Object does not have sufficient resources for a new link";
		break;
	case DNSTAT_BADACCOUNT: msg="The Account field in unacceptable";
		break;
	case DNSTAT_TOOLONG: msg="A field in the access control message was too long";
		break;
	default: msg=strerror(saved_errno);
		break;
	}
	return msg;
#else
	return strerror(saved_errno);
#endif
}