/*
 * Oscar File transfer (OFT) and Oscar Direct Connect (ODC).
 * (ODC is also referred to as DirectIM and IM Image.)
 *
 * There are a few static helper functions at the top, then 
 * ODC stuff, then ft stuff.
 *
 * I feel like this is a good place to explain OFT, so I'm going to 
 * do just that.  Each OFT packet has a header type.  I guess this 
 * is pretty similar to the subtype of a SNAC packet.  The type 
 * basically tells the other client the meaning of the OFT packet.  
 * There are two distinct types of file transfer, which I usually 
 * call "sendfile" and "getfile."  Sendfile is when you send a file 
 * to another AIM user.  Getfile is when you share a group of files, 
 * and other users request that you send them the files.
 *
 * A typical sendfile file transfer goes like this:
 *   1) Sender sends a channel 2 ICBM telling the other user that 
 *      we want to send them a file.  At the same time, we open a 
 *      listener socket (this should be done before sending the 
 *      ICBM) on some port, and wait for them to connect to us.  
 *      The ICBM we sent should contain our IP address and the port 
 *      number that we're listening on.
 *   2) The receiver connects to the sender on the given IP address 
 *      and port.  After the connection is established, the receiver 
 *      sends an ICBM signifying that we are ready and waiting.
 *   3) The sender sends an OFT PROMPT message over the OFT 
 *      connection.
 *   4) The receiver of the file sends back an exact copy of this 
 *      OFT packet, except the cookie is filled in with the cookie 
 *      from the ICBM.  I think this might be an attempt to verify 
 *      that the user that is connected is actually the guy that 
 *      we sent the ICBM to.  Oh, I've been calling this the ACK.
 *   5) The sender starts sending raw data across the connection 
 *      until the entire file has been sent.
 *   6) The receiver knows the file is finished because the sender 
 *      sent the file size in an earlier OFT packet.  So then the 
 *      receiver sends the DONE thingy (after filling in the 
 *      "received" checksum and size) and closes the connection.
 */

#define FAIM_INTERNAL
#ifdef HAVE_CONFIG_H
#include  <config.h>
#endif

#include <aim.h>

#ifndef _WIN32
#include <stdio.h>
#include <netdb.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <sys/utsname.h> /* for aim_odc_initiate */
#include <arpa/inet.h> /* for inet_ntoa */
#include <limits.h> /* for UINT_MAX */
#define G_DIR_SEPARATOR '/'
#endif

#ifdef _WIN32
#include "win32dep.h"
#endif

struct aim_odc_intdata {
	fu8_t cookie[8];
	char sn[MAXSNLEN+1];
	char ip[22];
};

/**
 * Convert the directory separator from / (0x2f) to ^A (0x01)
 *
 * @param name The filename to convert.
 */
static void aim_oft_dirconvert_tostupid(char *name)
{
	while (name[0]) {
		if (name[0] == 0x01)
			name[0] = G_DIR_SEPARATOR;
		name++;
	}
}

/**
 * Convert the directory separator from ^A (0x01) to / (0x2f)
 *
 * @param name The filename to convert.
 */
static void aim_oft_dirconvert_fromstupid(char *name)
{
	while (name[0]) {
		if (name[0] == G_DIR_SEPARATOR)
			name[0] = 0x01;
		name++;
	}
}

/**
 * Calculate oft checksum of buffer
 *
 * Prevcheck should be 0xFFFF0000 when starting a checksum of a file.  The 
 * checksum is kind of a rolling checksum thing, so each time you get bytes 
 * of a file you just call this puppy and it updates the checksum.  You can 
 * calculate the checksum of an entire file by calling this in a while or a 
 * for loop, or something.
 *
 * Thanks to Graham Booker for providing this improved checksum routine, 
 * which is simpler and should be more accurate than Josh Myer's original 
 * code. -- wtm
 *
 * This algorithm works every time I have tried it.  The other fails 
 * sometimes.  So, AOL who thought this up?  It has got to be the weirdest 
 * checksum I have ever seen.
 *
 * @param buffer Buffer of data to checksum.  Man I'd like to buff her...
 * @param bufsize Size of buffer.
 * @param prevcheck Previous checksum.
 */
faim_export fu32_t aim_oft_checksum_chunk(const fu8_t *buffer, int bufferlen, fu32_t prevcheck)
{
	fu32_t check = (prevcheck >> 16) & 0xffff, oldcheck;
	int i;
	unsigned short val;

	for (i=0; i<bufferlen; i++) {
		oldcheck = check;
		if (i&1)
			val = buffer[i];
		else
			val = buffer[i] << 8;
		check -= val;
		/*
		 * The following appears to be necessary.... It happens 
		 * every once in a while and the checksum doesn't fail.
		 */
		if (check > oldcheck)
			check--;
	}
	check = ((check & 0x0000ffff) + (check >> 16));
	check = ((check & 0x0000ffff) + (check >> 16));
	return check << 16;
}

faim_export fu32_t aim_oft_checksum_file(char *filename) {
	FILE *fd;
	fu32_t checksum = 0xffff0000;

	if ((fd = fopen(filename, "rb"))) {
		int bytes;
		fu8_t buffer[1024];

		while ((bytes = fread(buffer, 1, 1024, fd)))
			checksum = aim_oft_checksum_chunk(buffer, bytes, checksum);
		fclose(fd);
	}

	return checksum;
}

/**
 * After establishing a listening socket, this is called to accept a connection.  It
 * clones the conn used by the listener, and passes both of these to a signal handler.
 * The signal handler should close the listener conn and keep track of the new conn,
 * since this is what is used for file transfers and what not.
 *
 * @param sess The session.
 * @param cur The conn the incoming connection is on.
 * @return Return 0 if no errors, otherwise return the error number.
 */
faim_export int aim_handlerendconnect(aim_session_t *sess, aim_conn_t *cur)
{
	int acceptfd = 0;
	struct sockaddr addr;
	socklen_t addrlen = sizeof(addr);
	int ret = 0;
	aim_conn_t *newconn;
	char ip[20];
	unsigned short port;

	if ((acceptfd = accept(cur->fd, &addr, &addrlen)) == -1)
		return 0; /* not an error */

	/* Also accept inet6? */
	if (addr.sa_family != AF_INET) {
		close(acceptfd);
		aim_conn_close(cur);
		return -1;
	}

	strncpy(ip, inet_ntoa(((struct sockaddr_in *)&addr)->sin_addr), sizeof(ip));
	port = ntohs(((struct sockaddr_in *)&addr)->sin_port);

	if (!(newconn = aim_cloneconn(sess, cur))) {
		close(acceptfd);
		aim_conn_close(cur);
		return -ENOMEM;
	}

	newconn->type = AIM_CONN_TYPE_RENDEZVOUS;
	newconn->fd = acceptfd;

	if (newconn->subtype == AIM_CONN_SUBTYPE_OFT_DIRECTIM) {
		aim_rxcallback_t userfunc;
		struct aim_odc_intdata *priv;

		priv = (struct aim_odc_intdata *)(newconn->internal = cur->internal);
		cur->internal = NULL;
		snprintf(priv->ip, sizeof(priv->ip), "%s:%hu", ip, port);

		if ((userfunc = aim_callhandler(sess, newconn, AIM_CB_FAM_OFT, AIM_CB_OFT_DIRECTIM_ESTABLISHED)))
			ret = userfunc(sess, NULL, newconn, cur);

	} else if (newconn->subtype == AIM_CONN_SUBTYPE_OFT_GETFILE) {
	} else if (newconn->subtype == AIM_CONN_SUBTYPE_OFT_SENDFILE) {
		aim_rxcallback_t userfunc;

		if ((userfunc = aim_callhandler(sess, newconn, AIM_CB_FAM_OFT, AIM_CB_OFT_ESTABLISHED)))
			ret = userfunc(sess, NULL, newconn, cur);

	} else {
		faimdprintf(sess, 1,"Got a connection on a listener that's not rendezvous.  Closing connection.\n");
		aim_conn_close(newconn);
		ret = -1;
	}

	return ret;
}

/**
 * Send client-to-client typing notification over an established direct connection.
 *
 * @param sess The session.
 * @param conn The already-connected ODC connection.
 * @param typing If 0x0002, sends a "typing" message, 0x0001 sends "typed," and 
 *        0x0000 sends "stopped."
 * @return Return 0 if no errors, otherwise return the error number.
 */
faim_export int aim_odc_send_typing(aim_session_t *sess, aim_conn_t *conn, int typing)
{
	struct aim_odc_intdata *intdata = (struct aim_odc_intdata *)conn->internal;
	aim_frame_t *fr;
	aim_bstream_t *hdrbs;
	fu8_t *hdr;
	int hdrlen = 0x44;

	if (!sess || !conn || (conn->type != AIM_CONN_TYPE_RENDEZVOUS))
		return -EINVAL;

	if (!(fr = aim_tx_new(sess, conn, AIM_FRAMETYPE_OFT, 0x0001, 0)))
		return -ENOMEM;
	memcpy(fr->hdr.rend.magic, "ODC2", 4);
	fr->hdr.rend.hdrlen = hdrlen + 8;

	if (!(hdr = calloc(1, hdrlen))) {
		aim_frame_destroy(fr);
		return -ENOMEM;
	}

	hdrbs = &(fr->data);
	aim_bstream_init(hdrbs, hdr, hdrlen);

	aimbs_put16(hdrbs, 0x0006);
	aimbs_put16(hdrbs, 0x0000);
	aimbs_putraw(hdrbs, intdata->cookie, 8);
	aimbs_put16(hdrbs, 0x0000);
	aimbs_put16(hdrbs, 0x0000);
	aimbs_put16(hdrbs, 0x0000);
	aimbs_put16(hdrbs, 0x0000);
	aimbs_put32(hdrbs, 0x00000000);
	aimbs_put16(hdrbs, 0x0000);
	aimbs_put16(hdrbs, 0x0000);
	aimbs_put16(hdrbs, 0x0000);

	if (typing == 0x0002)
		aimbs_put16(hdrbs, 0x0002 | 0x0008);
	else if (typing == 0x0001)
		aimbs_put16(hdrbs, 0x0002 | 0x0004);
	else
		aimbs_put16(hdrbs, 0x0002);

	aimbs_put16(hdrbs, 0x0000);
	aimbs_put16(hdrbs, 0x0000);
	aimbs_putraw(hdrbs, sess->sn, strlen(sess->sn));

	aim_bstream_setpos(hdrbs, 52); /* bleeehh */

	aimbs_put8(hdrbs, 0x00);
	aimbs_put16(hdrbs, 0x0000);
	aimbs_put16(hdrbs, 0x0000);
	aimbs_put16(hdrbs, 0x0000);
	aimbs_put16(hdrbs, 0x0000);
	aimbs_put16(hdrbs, 0x0000);
	aimbs_put16(hdrbs, 0x0000);
	aimbs_put16(hdrbs, 0x0000);
	aimbs_put8(hdrbs, 0x00);

	/* end of hdr */

	aim_tx_enqueue(sess, fr);

	return 0;
}

/**
 * Send client-to-client IM over an established direct connection.
 * Call this just like you would aim_send_im, to send a directim.
 * 
 * @param sess The session.
 * @param conn The already-connected ODC connection.
 * @param msg Null-terminated string to send.
 * @param len The length of the message to send, including binary data.
 * @param encoding 0 for ascii, 2 for Unicode, 3 for ISO 8859-1.
 * @param isawaymsg 0 if this is not an auto-response, 1 if it is.
 * @return Return 0 if no errors, otherwise return the error number.
 */
faim_export int aim_odc_send_im(aim_session_t *sess, aim_conn_t *conn, const char *msg, int len, int encoding, int isawaymsg)
{
	aim_frame_t *fr;
	aim_bstream_t *hdrbs;
	struct aim_odc_intdata *intdata = (struct aim_odc_intdata *)conn->internal;
	int hdrlen = 0x44;
	fu8_t *hdr;

	if (!sess || !conn || (conn->type != AIM_CONN_TYPE_RENDEZVOUS) || !msg)
		return -EINVAL;

	if (!(fr = aim_tx_new(sess, conn, AIM_FRAMETYPE_OFT, 0x01, 0)))
		return -ENOMEM;

	memcpy(fr->hdr.rend.magic, "ODC2", 4);
	fr->hdr.rend.hdrlen = hdrlen + 8;

	if (!(hdr = calloc(1, hdrlen + len))) {
		aim_frame_destroy(fr);
		return -ENOMEM;
	}

	hdrbs = &(fr->data);
	aim_bstream_init(hdrbs, hdr, hdrlen + len);

	aimbs_put16(hdrbs, 0x0006);
	aimbs_put16(hdrbs, 0x0000);
	aimbs_putraw(hdrbs, intdata->cookie, 8);
	aimbs_put16(hdrbs, 0x0000);
	aimbs_put16(hdrbs, 0x0000);
	aimbs_put16(hdrbs, 0x0000);
	aimbs_put16(hdrbs, 0x0000);
	aimbs_put32(hdrbs, len);
	aimbs_put16(hdrbs, encoding);
	aimbs_put16(hdrbs, 0x0000);
	aimbs_put16(hdrbs, 0x0000);

	/* flags - used for typing notification and to mark if this is an away message */
	aimbs_put16(hdrbs, 0x0000 | isawaymsg);

	aimbs_put16(hdrbs, 0x0000);
	aimbs_put16(hdrbs, 0x0000);
	aimbs_putraw(hdrbs, sess->sn, strlen(sess->sn));

	aim_bstream_setpos(hdrbs, 52); /* bleeehh */

	aimbs_put8(hdrbs, 0x00);
	aimbs_put16(hdrbs, 0x0000);
	aimbs_put16(hdrbs, 0x0000);
	aimbs_put16(hdrbs, 0x0000);
	aimbs_put16(hdrbs, 0x0000);
	aimbs_put16(hdrbs, 0x0000);
	aimbs_put16(hdrbs, 0x0000);
	aimbs_put16(hdrbs, 0x0000);
	aimbs_put8(hdrbs, 0x00);

	/* end of hdr2 */

#if 0 /* XXX - this is how you send buddy icon info... */	
	aimbs_put16(hdrbs, 0x0008);
	aimbs_put16(hdrbs, 0x000c);
	aimbs_put16(hdrbs, 0x0000);
	aimbs_put16(hdrbs, 0x1466);
	aimbs_put16(hdrbs, 0x0001);
	aimbs_put16(hdrbs, 0x2e0f);
	aimbs_put16(hdrbs, 0x393e);
	aimbs_put16(hdrbs, 0xcac8);
#endif
	aimbs_putraw(hdrbs, msg, len);

	aim_tx_enqueue(sess, fr);

	return 0;
}

/**
 * Get the screen name of the peer of a direct connection.
 *
 * @param conn The ODC connection.
 * @return The screen name of the dude, or NULL if there was an anomaly.
 */
faim_export const char *aim_odc_getsn(aim_conn_t *conn)
{
	struct aim_odc_intdata *intdata;

	if (!conn || !conn->internal)
		return NULL;

	if ((conn->type != AIM_CONN_TYPE_RENDEZVOUS) ||
			(conn->subtype != AIM_CONN_SUBTYPE_OFT_DIRECTIM))
		return NULL;

	intdata = (struct aim_odc_intdata *)conn->internal;

	return intdata->sn;
}

/**
 * Get the cookie of a direct connection.
 *
 * @param conn The ODC connection.
 * @return The cookie, an 8 byte unterminated string, or NULL if there was an anomaly.
 */
faim_export const char *aim_odc_getcookie(aim_conn_t *conn)
{
	struct aim_odc_intdata *intdata;

	if (!conn || !conn->internal)
		return NULL;

	intdata = (struct aim_odc_intdata *)conn->internal;

	return intdata->cookie;
}

/**
 * Find the conn of a direct connection with the given buddy.
 *
 * @param sess The session.
 * @param sn The screen name of the buddy whose direct connection you want to find.
 * @return The conn for the direct connection with the given buddy, or NULL if no 
 *         connection was found.
 */
faim_export aim_conn_t *aim_odc_getconn(aim_session_t *sess, const char *sn)
{
	aim_conn_t *cur;
	struct aim_odc_intdata *intdata;

	if (!sess || !sn || !strlen(sn))
		return NULL;

	for (cur = sess->connlist; cur; cur = cur->next) {
		if ((cur->type == AIM_CONN_TYPE_RENDEZVOUS) && (cur->subtype == AIM_CONN_SUBTYPE_OFT_DIRECTIM)) {
			intdata = cur->internal;
			if (!aim_sncmp(intdata->sn, sn))
				return cur;
		}
	}

	return NULL;
}

/**
 * For those times when we want to open up the direct connection channel ourselves.
 *
 * You'll want to set up some kind of watcher on this socket.
 * When the state changes, call aim_handlerendconnection with
 * the connection returned by this.  aim_handlerendconnection
 * will accept the pending connection and stop listening.
 *
 * @param sess The session
 * @param sn The screen name to connect to.
 * @return The new connection.
 */
faim_export aim_conn_t *aim_odc_initiate(aim_session_t *sess, const char *sn, int listenfd,
                                         const fu8_t *localip, fu16_t port, const fu8_t *mycookie)
{
	aim_conn_t *newconn;
	aim_msgcookie_t *cookie;
	struct aim_odc_intdata *priv;
	fu8_t ck[8];

	if (!localip)
		return NULL;

	if (mycookie) {
		memcpy(ck, mycookie, 8);
		aim_im_sendch2_odcrequest(sess, ck, TRUE, sn, localip, port);
	} else
		aim_im_sendch2_odcrequest(sess, ck, FALSE, sn, localip, port);

	cookie = (aim_msgcookie_t *)calloc(1, sizeof(aim_msgcookie_t));
	memcpy(cookie->cookie, ck, 8);
	cookie->type = AIM_COOKIETYPE_OFTIM;

	/* this one is for the cookie */
	priv = (struct aim_odc_intdata *)calloc(1, sizeof(struct aim_odc_intdata));

	memcpy(priv->cookie, ck, 8);
	strncpy(priv->sn, sn, sizeof(priv->sn));
	cookie->data = priv;
	aim_cachecookie(sess, cookie);

	/* XXX - switch to aim_cloneconn()? */
	if (!(newconn = aim_newconn(sess, AIM_CONN_TYPE_LISTENER, NULL))) {
		close(listenfd);
		return NULL;
	}

	/* this one is for the conn */
	priv = (struct aim_odc_intdata *)calloc(1, sizeof(struct aim_odc_intdata));

	memcpy(priv->cookie, ck, 8);
	strncpy(priv->sn, sn, sizeof(priv->sn));

	newconn->fd = listenfd;
	newconn->subtype = AIM_CONN_SUBTYPE_OFT_DIRECTIM;
	newconn->internal = priv;
	newconn->lastactivity = time(NULL);

	return newconn;
}

/**
 * Connect directly to the given buddy for directim.
 *
 * This is a wrapper for aim_newconn.
 *
 * If addr is NULL, the socket is not created, but the connection is 
 * allocated and setup to connect.
 *
 * @param sess The Godly session.
 * @param sn The screen name we're connecting to.  I hope it's a girl...
 * @param addr Address to connect to.
 * @return The new connection.
 */
faim_export aim_conn_t *aim_odc_connect(aim_session_t *sess, const char *sn, const char *addr, const fu8_t *cookie)
{
	aim_conn_t *newconn;
	struct aim_odc_intdata *intdata;

	if (!sess || !sn)
		return NULL;

	if (!(intdata = calloc(1, sizeof(struct aim_odc_intdata))))
		return NULL;
	memcpy(intdata->cookie, cookie, 8);
	strncpy(intdata->sn, sn, sizeof(intdata->sn));
	if (addr)
		strncpy(intdata->ip, addr, sizeof(intdata->ip));

	/* XXX - verify that non-blocking connects actually work */
	if (!(newconn = aim_newconn(sess, AIM_CONN_TYPE_RENDEZVOUS, addr))) {
		free(intdata);
		return NULL;
	}

	newconn->internal = intdata;
	newconn->subtype = AIM_CONN_SUBTYPE_OFT_DIRECTIM;

	return newconn;
}

/**
 * Sometimes you just don't know with these kinds of people.
 *
 * @param sess The session.
 * @param conn The ODC connection of the incoming data.
 * @param frr The frame allocated for the incoming data.
 * @param bs It stands for "bologna sandwich."
 * @return Return 0 if no errors, otherwise return the error number.
 */
static int handlehdr_odc(aim_session_t *sess, aim_conn_t *conn, aim_frame_t *frr, aim_bstream_t *bs)
{
	aim_frame_t fr;
	int ret = 0;
	aim_rxcallback_t userfunc;
	fu32_t payloadlength;
	fu16_t flags, encoding;
	char *snptr = NULL;

	fr.conn = conn;

	/* AAA - ugly */
	aim_bstream_setpos(bs, 20);
	payloadlength = aimbs_get32(bs);

	aim_bstream_setpos(bs, 24);
	encoding = aimbs_get16(bs);

	aim_bstream_setpos(bs, 30);
	flags = aimbs_get16(bs);

	aim_bstream_setpos(bs, 36);
	/* XXX - create an aimbs_getnullstr function? */
	snptr = aimbs_getstr(bs, 32); /* Next 32 bytes contain the sn, padded with null chars */

	faimdprintf(sess, 2, "faim: OFT frame: handlehdr_odc: %04x / %04x / %s\n", payloadlength, flags, snptr);

	if (flags & 0x0008) {
		if ((userfunc = aim_callhandler(sess, conn, AIM_CB_FAM_OFT, AIM_CB_OFT_DIRECTIMTYPING)))
			ret = userfunc(sess, &fr, snptr, 2);
	} else if (flags & 0x0004) {
		if ((userfunc = aim_callhandler(sess, conn, AIM_CB_FAM_OFT, AIM_CB_OFT_DIRECTIMTYPING)))
			ret = userfunc(sess, &fr, snptr, 1);
	} else {
		if ((userfunc = aim_callhandler(sess, conn, AIM_CB_FAM_OFT, AIM_CB_OFT_DIRECTIMTYPING)))
			ret = userfunc(sess, &fr, snptr, 0);
	}

	if ((payloadlength != 0) && (payloadlength != UINT_MAX)) {
		char *msg;
		int recvd = 0;
		int i, isawaymsg;

		isawaymsg = flags & 0x0001;

		if (!(msg = calloc(1, payloadlength+1))) {
			free(snptr);
			return -ENOMEM;
		}

		while (payloadlength - recvd) {
			if (payloadlength - recvd >= 1024)
				i = aim_recv(conn->fd, &msg[recvd], 1024);
			else 
				i = aim_recv(conn->fd, &msg[recvd], payloadlength - recvd);
			if (i <= 0) {
				free(msg);
				free(snptr);
				return -1;
			}
			recvd = recvd + i;
			if ((userfunc = aim_callhandler(sess, conn, AIM_CB_FAM_SPECIAL, AIM_CB_SPECIAL_IMAGETRANSFER)))
				ret = userfunc(sess, &fr, snptr, (double)recvd / payloadlength);
		}
		
		if ((userfunc = aim_callhandler(sess, conn, AIM_CB_FAM_OFT, AIM_CB_OFT_DIRECTIMINCOMING)))
			ret = userfunc(sess, &fr, snptr, msg, payloadlength, encoding, isawaymsg);

		free(msg);
	}

	free(snptr);

	return ret;
}

faim_export struct aim_oft_info *aim_oft_createinfo(aim_session_t *sess, const fu8_t *cookie, const char *sn, const char *ip, fu16_t port, fu32_t size, fu32_t modtime, char *filename)
{
	struct aim_oft_info *new;

	if (!sess)
		return NULL;

	if (!(new = (struct aim_oft_info *)calloc(1, sizeof(struct aim_oft_info))))
		return NULL;

	new->sess = sess;
	if (cookie)
		memcpy(new->cookie, cookie, 8);
	if (ip)
		new->clientip = strdup(ip);
	if (sn)
		new->sn = strdup(sn);
	new->port = port;
	new->fh.totfiles = 1;
	new->fh.filesleft = 1;
	new->fh.totparts = 1;
	new->fh.partsleft = 1;
	new->fh.totsize = size;
	new->fh.size = size;
	new->fh.modtime = modtime;
	new->fh.checksum = 0xffff0000;
	new->fh.rfrcsum = 0xffff0000;
	new->fh.rfcsum = 0xffff0000;
	new->fh.recvcsum = 0xffff0000;
	strncpy(new->fh.idstring, "OFT_Windows ICBMFT V1.1 32", 31);
	if (filename) {
		strncpy(new->fh.name, filename, 63);
		new->fh.name[63] = '\0';
	}

	new->next = sess->oft_info;
	sess->oft_info = new;

	return new;
}

/**
 * Remove the given oft_info struct from the oft_info linked list, and 
 * then free its memory.
 *
 * @param sess The session.
 * @param oft_info The aim_oft_info struct that we're destroying.
 * @return Return 0 if no errors, otherwise return the error number.
 */
faim_export int aim_oft_destroyinfo(struct aim_oft_info *oft_info)
{
	aim_session_t *sess;

	if (!oft_info || !(sess = oft_info->sess))
		return -EINVAL;

	if (sess->oft_info && (sess->oft_info == oft_info)) {
		sess->oft_info = sess->oft_info->next;
	} else {
		struct aim_oft_info *cur;
		for (cur=sess->oft_info; (cur->next && (cur->next!=oft_info)); cur=cur->next);
		if (cur->next)
			cur->next = cur->next->next;
	}

	free(oft_info->sn);
	free(oft_info->proxyip);
	free(oft_info->clientip);
	free(oft_info->verifiedip);
	free(oft_info);

	return 0;
}

/**
 * Creates a listener socket so the other dude can connect to us.
 *
 * You'll want to set up some kind of watcher on this socket.  
 * When the state changes, call aim_handlerendconnection with 
 * the connection returned by this.  aim_handlerendconnection 
 * will accept the pending connection and stop listening.
 *
 * @param sess The session.
 * @param oft_info File transfer information associated with this 
 *        connection.
 * @return Return 0 if no errors, otherwise return the error number.
 */
faim_export int aim_sendfile_listen(aim_session_t *sess, struct aim_oft_info *oft_info, int listenfd)
{
	if (!oft_info)
		return -EINVAL;

	if (!(oft_info->conn = aim_newconn(sess, AIM_CONN_TYPE_LISTENER, NULL))) {
		close(listenfd);
		return -ENOMEM;
	}

	oft_info->conn->fd = listenfd;
	oft_info->conn->subtype = AIM_CONN_SUBTYPE_OFT_SENDFILE;
	oft_info->conn->lastactivity = time(NULL);

	return 0;
}

/**
 * Extract an &aim_fileheader_t from the given buffer.
 *
 * @param bs The should be from an incoming rendezvous packet.
 * @return A pointer to new struct on success, or NULL on error.
 */
static struct aim_fileheader_t *aim_oft_getheader(aim_bstream_t *bs)
{
	struct aim_fileheader_t *fh;

	if (!(fh = calloc(1, sizeof(struct aim_fileheader_t))))
		return NULL;

	/* The bstream should be positioned after the hdrtype. */
	aimbs_getrawbuf(bs, fh->bcookie, 8);
	fh->encrypt = aimbs_get16(bs);
	fh->compress = aimbs_get16(bs);
	fh->totfiles = aimbs_get16(bs);
	fh->filesleft = aimbs_get16(bs);
	fh->totparts = aimbs_get16(bs);
	fh->partsleft = aimbs_get16(bs);
	fh->totsize = aimbs_get32(bs);
	fh->size = aimbs_get32(bs);
	fh->modtime = aimbs_get32(bs);
	fh->checksum = aimbs_get32(bs);
	fh->rfrcsum = aimbs_get32(bs);
	fh->rfsize = aimbs_get32(bs);
	fh->cretime = aimbs_get32(bs);
	fh->rfcsum = aimbs_get32(bs);
	fh->nrecvd = aimbs_get32(bs);
	fh->recvcsum = aimbs_get32(bs);
	aimbs_getrawbuf(bs, fh->idstring, 32);
	fh->flags = aimbs_get8(bs);
	fh->lnameoffset = aimbs_get8(bs);
	fh->lsizeoffset = aimbs_get8(bs);
	aimbs_getrawbuf(bs, fh->dummy, 69);
	aimbs_getrawbuf(bs, fh->macfileinfo, 16);
	fh->nencode = aimbs_get16(bs);
	fh->nlanguage = aimbs_get16(bs);
	aimbs_getrawbuf(bs, fh->name, 64); /* XXX - filenames longer than 64B */
	fh->name[63] = '\0';

	return fh;
} 

/**
 * Fills a buffer with network-order fh data
 *
 * @param bs A bstream to fill -- automatically initialized
 * @param fh A struct aim_fileheader_t to get data from.
 * @return Return non-zero on error.
 */
static int aim_oft_buildheader(aim_bstream_t *bs, struct aim_fileheader_t *fh)
{ 
	fu8_t *hdr;

	if (!bs || !fh)
		return -EINVAL;

	if (!(hdr = (unsigned char *)calloc(1, 0x100 - 8)))
		return -ENOMEM;

	aim_bstream_init(bs, hdr, 0x100 - 8);
	aimbs_putraw(bs, fh->bcookie, 8);
	aimbs_put16(bs, fh->encrypt);
	aimbs_put16(bs, fh->compress);
	aimbs_put16(bs, fh->totfiles);
	aimbs_put16(bs, fh->filesleft);
	aimbs_put16(bs, fh->totparts);
	aimbs_put16(bs, fh->partsleft);
	aimbs_put32(bs, fh->totsize);
	aimbs_put32(bs, fh->size);
	aimbs_put32(bs, fh->modtime);
	aimbs_put32(bs, fh->checksum);
	aimbs_put32(bs, fh->rfrcsum);
	aimbs_put32(bs, fh->rfsize);
	aimbs_put32(bs, fh->cretime);
	aimbs_put32(bs, fh->rfcsum);
	aimbs_put32(bs, fh->nrecvd);
	aimbs_put32(bs, fh->recvcsum);
	aimbs_putraw(bs, fh->idstring, 32);
	aimbs_put8(bs, fh->flags);
	aimbs_put8(bs, fh->lnameoffset);
	aimbs_put8(bs, fh->lsizeoffset);
	aimbs_putraw(bs, fh->dummy, 69);
	aimbs_putraw(bs, fh->macfileinfo, 16);
	aimbs_put16(bs, fh->nencode);
	aimbs_put16(bs, fh->nlanguage);
	aimbs_putraw(bs, fh->name, 64);	/* XXX - filenames longer than 64B */

	return 0;
}

/**
 * Create an OFT packet based on the given information, and send it on its merry way.
 *
 * @param sess The session.
 * @param type The subtype of the OFT packet we're sending.
 * @param oft_info The aim_oft_info struct with the connection and OFT 
 *        info we're sending.
 * @return Return 0 if no errors, otherwise return the error number.
 */
faim_export int aim_oft_sendheader(aim_session_t *sess, fu16_t type, struct aim_oft_info *oft_info)
{
	aim_frame_t *fr;

	if (!sess || !oft_info || !oft_info->conn || (oft_info->conn->type != AIM_CONN_TYPE_RENDEZVOUS))
		return -EINVAL;

#if 0
	/*
	 * If you are receiving a file, the cookie should be null, if you are sending a 
	 * file, the cookie should be the same as the one used in the ICBM negotiation 
	 * SNACs.
	 */
	fh->lnameoffset = 0x1a;
	fh->lsizeoffset = 0x10;

	/* apparently 0 is ASCII, 2 is UCS-2 */
	/* it is likely that 3 is ISO 8859-1 */
	/* I think "nlanguage" might be the same thing as "subenc" in im.c */
	fh->nencode = 0x0000;
	fh->nlanguage = 0x0000;
#endif

	aim_oft_dirconvert_tostupid(oft_info->fh.name);

	if (!(fr = aim_tx_new(sess, oft_info->conn, AIM_FRAMETYPE_OFT, type, 0)))
		return -ENOMEM;

	if (aim_oft_buildheader(&fr->data, &oft_info->fh) == -1) {
		aim_frame_destroy(fr);
		return -ENOMEM;
	}

	memcpy(fr->hdr.rend.magic, "OFT2", 4);
	fr->hdr.rend.hdrlen = aim_bstream_curpos(&fr->data) + 8;

	aim_tx_enqueue(sess, fr);

	return 0;
}

/**
 * Handle incoming data on a rendezvous connection.  This is analogous to the 
 * consumesnac function in rxhandlers.c, and I really think this should probably 
 * be in rxhandlers.c as well, but I haven't finished cleaning everything up yet.
 *
 * @param sess The session.
 * @param fr The frame allocated for the incoming data.
 * @return Return 0 if the packet was handled correctly, otherwise return the 
 *         error number.
 */
faim_internal int aim_rxdispatch_rendezvous(aim_session_t *sess, aim_frame_t *fr)
{
	aim_conn_t *conn = fr->conn;
	int ret = 1;

	if (conn->subtype == AIM_CONN_SUBTYPE_OFT_DIRECTIM) {
		if (fr->hdr.rend.type == 0x0001)
			ret = handlehdr_odc(sess, conn, fr, &fr->data);
		else
			faimdprintf(sess, 0, "faim: ODC directim frame unknown, type is %04x\n", fr->hdr.rend.type);

	} else {
		aim_rxcallback_t userfunc;
		struct aim_fileheader_t *header = aim_oft_getheader(&fr->data);
		aim_oft_dirconvert_fromstupid(header->name); /* XXX - This should be client-side */

		if ((userfunc = aim_callhandler(sess, conn, AIM_CB_FAM_OFT, fr->hdr.rend.type)))
			ret = userfunc(sess, fr, conn, header->bcookie, header);

		free(header);
	}

	if (ret == -1)
		aim_conn_close(conn);

	return ret;
}
