/*
 * msnp2p.c
 *
 * Wizb Technologies' Combined MSNP2P/MSNSLP layer
 *
 * (c) 2002-2005 Thomas White <taw27@srcf.ucam.org>
 *  Part of TuxMessenger - GTK+-based MSN Messenger client
 *
 * This package 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; version 2 dated June, 1991.
 *
 * This package 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.
 *
 * You should have received a copy of the GNU General Public License
 * along with this package; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
 * 02111-1307, USA.
 *
 */

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

#include <stdio.h>
#include <stdint.h>
#include <string.h>
#include <stdlib.h>
#include <netinet/in.h>
#include <glob.h>
#include <sys/stat.h>
#include <assert.h>

#include "sbsessions.h"
#include "mime.h"
#include "options.h"
#include "debug.h"
#include "sbprotocol.h"
#include "avatars.h"
#include "routines.h"
#include "xml.h"
#include "contactlist.h"

#define MSNP2P_DEBUG

static GList *msnp2p_list = NULL;

struct _mpsession {

	SbSession *parent;
	char *username;
	enum {
		MSNP2P_DIR_RECV,
		MSNP2P_DIR_SEND
	} direction;

	unsigned int baseidentifier;
	unsigned int id_increment;
	enum {
		MSNP2P_TYPE_DP,
		MSNP2P_TYPE_INK,
		MSNP2P_TYPE_FT
	} type;
	unsigned int session_id;
	FILE *fh;
	char *save_filename;
	char *sha1d;			/* The SHA1D field from the MSNObject, after xml_killillegalchars. */
	char *via;
	char *call_id;
	size_t offset;
	void *data;
	guint delete_timeout;

};
typedef struct _mpsession MpSession;

struct _mpheader {

	uint32_t session_id;
	uint32_t identifier;
	uint64_t offset;
	uint64_t total_size;
	uint32_t size;
	uint32_t flags;
	uint32_t ack_id;
	uint32_t ack_sess;
	uint64_t ack_size;

};
typedef struct _mpheader MpHeader;

static MpSession *msnp2p_new() {

	MpSession *mpsession = malloc(sizeof(MpSession));

	mpsession->save_filename = NULL;
	mpsession->sha1d = NULL;
	mpsession->via = NULL;
	mpsession->call_id = NULL;
	mpsession->username = NULL;
	mpsession->data = NULL;
	mpsession->delete_timeout = 0;

	return mpsession;

}

static gboolean msnp2p_closesession(MpSession *mpsession) {

	assert(mpsession != NULL);

	if ( mpsession->via != NULL ) {
		free(mpsession->via);
	}
	if ( mpsession->call_id != NULL ) {
		free(mpsession->call_id);
	}
	if ( mpsession->username != NULL ) {
		debug_print("MP %8p: Deleting an MSNP2P session to '%s'\n", mpsession, mpsession->username);
		free(mpsession->username);
	} else {
		debug_print("MP %8p: Deleting an MSNP2P session.\n", mpsession);
	}
	if ( mpsession->save_filename != NULL ) {
		free(mpsession->save_filename);
	}
	if ( mpsession->sha1d != NULL ) {
		free(mpsession->sha1d);
	}
	if ( mpsession->delete_timeout != 0 ) {
		g_source_remove(mpsession->delete_timeout);
	}
	if ( mpsession->data != NULL ) {
		free(mpsession->data);
	}

	msnp2p_list = g_list_remove(msnp2p_list, mpsession);

	free(mpsession);

	return FALSE;

}

/* Yes.  Not Pretty. */
static void msnp2p_send(SbSession *session, MpHeader mpheader, const char *username, const char *payload, int payload_length, int app_id) {

	int total_message_length;
	char *msnp2p_text;
	char *message_stub;
	int stub_length;
	int sf;
	char *final;

	/* Create the overall header for the message. */
	msnp2p_text = malloc(74 + strlen(username));
	if ( msnp2p_text == NULL ) {
		debug_print("MP: Not enough memory to send MSNP2P message.\n");
		return;
	}
	strcpy(msnp2p_text, "MIME-Version: 1.0\r\nContent-Type: application/x-msnmsgrp2p\r\nP2P-Dest: ");
	strcat(msnp2p_text, username);
	strcat(msnp2p_text, "\r\n\r\n");

	/* Calculate the total message length. */
	total_message_length = strlen(msnp2p_text) + 48 + payload_length + 4;

	/* Snippet */
	message_stub = malloc(9);
	if ( message_stub == NULL ) {

		debug_print("MP: Not enough memory to send MSNP2P message.\n");
		free(msnp2p_text);
		return;

	}
	assert(total_message_length < 10000);	/* i.e. fits into four digits. */
	sprintf(message_stub, "D %i\r\n", total_message_length);
	stub_length = strlen(message_stub);

	final = malloc(stub_length + strlen(msnp2p_text) + 48 + payload_length + 4);
	if ( final == NULL ) {

		debug_print("MP: Not enough memory to send MSNP2P message.\n");
		free(message_stub);
		free(msnp2p_text);
		return;

	}

	strcpy(final, message_stub);
	free(message_stub);
	strcat(final, msnp2p_text);
	free(msnp2p_text);
	sf = strlen(final);

	memcpy (final+sf, &mpheader, 48);
	memcpy (final+sf+48, payload, payload_length);
	*((int *)(final+sf+48+payload_length)) = htonl(app_id);

	sbprotocol_sendtr_nonewline(session, "MSG", final, total_message_length+stub_length);
	free(final);

}

static gint msnp2p_compare_identifier(MpSession *mpsession, unsigned int *identifier) {

	if ( mpsession->baseidentifier == *identifier ) {
		return 0;
	}

	return 1;

}

static gint msnp2p_compare_parent(MpSession *mpsession, SbSession **parent) {

	if ( mpsession->parent == *parent ) {
		return 0;
	}

	return 1;

}

static gint msnp2p_compare_sessionid(MpSession *mpsession, unsigned int *sessionid) {

	if ( mpsession->session_id == *sessionid ) {
		return 0;
	}

	return 1;

}

static gint msnp2p_compare_callid(MpSession *mpsession, char *call_id) {

	if ( mpsession->call_id != NULL ) {
		if ( strcmp(mpsession->call_id, call_id) == 0 ) {
			return 0;
		}
	}

	return 1;

}

static gint msnp2p_compare_savefilename(MpSession *mpsession, char *save_filename) {

	if ( mpsession->save_filename != NULL ) {
		if ( strcmp(mpsession->save_filename, save_filename) == 0 ) {
			return 0;
		}
	}

	return 1;

}

/*static gint msnp2p_compare_sha1d(MpSession *mpsession, char *sha1d) {

	if ( mpsession->sha1d != NULL ) {
		if ( strcmp(mpsession->sha1d, sha1d) == 0 ) {
			return 0;
		}
	}

	return 1;

}*/

static MpSession *msnp2p_find_identifier(unsigned long int identifier) {

	GList *result;

	result = g_list_find_custom(msnp2p_list, &identifier, (GCompareFunc)msnp2p_compare_identifier);

	if ( result != NULL ) {
		return (MpSession *)result->data;
	}

	return NULL;

}

static MpSession *msnp2p_find_sessionid(unsigned long int sessionid) {

	GList *result;

	result = g_list_find_custom(msnp2p_list, &sessionid, (GCompareFunc)msnp2p_compare_sessionid);

	if ( result != NULL ) {
		return (MpSession *)result->data;
	}

	return NULL;

}

static MpSession *msnp2p_find_callid(char *callid) {

	GList *result;

	result = g_list_find_custom(msnp2p_list, callid, (GCompareFunc)msnp2p_compare_callid);

	if ( result != NULL ) {
		return (MpSession *)result->data;
	}

	return NULL;

}

/* Who invented this cr*p? */
static void msnp2p_inc(MpSession *mpsession) {

	mpsession->id_increment++;
	if ( mpsession->id_increment == -1 ) {
		mpsession->id_increment = 1;
	}

}

static MpSession *msnp2p_check_ok(const char *msnslp) {

	char *session_id_string;
	MpSession *mpsession;

	session_id_string = mime_getfield_anywhere(msnslp, "SessionID");
	if ( strlen(session_id_string) == 0 ) {
		debug_print("MP: Couldn't find SessionID field.\n");
		free(session_id_string);
		return NULL;
	}
	mpsession = msnp2p_find_sessionid(atoi(session_id_string));
	free(session_id_string);

	if ( strncmp(msnslp, "MSNSLP/1.0 200 OK", 17) == 0 ) {

		debug_print("MP: Got MSNSLP/1.0 200 OK - ");
		if ( mpsession == NULL ) {
			debug_print("but session not found.\n");
		} else {
			debug_print("and session found.\n");
		}

	}

	return mpsession;

}

static int msnp2p_check_bye(SbSession *session, const char *msnslp, MpHeader *mpheader) {

	char *callid_string;
	MpSession *mpsession;

	callid_string = mime_getfield_anywhere(msnslp, "Call-ID");
	if ( callid_string == NULL ) {
		debug_print("MP: Couldn't find Call-ID field.\n");
		return 0;
	}
	mpsession = msnp2p_find_callid(callid_string);
	free(callid_string);

	if ( strncmp(msnslp, "BYE MSNMSGR", 11) == 0 ) {

		debug_print("MP: Got BYE MSNMSGR - ");
		if ( mpsession == NULL ) {
			debug_print("but session not found.\n");
		} else {

			MpHeader acknowledgement;

			debug_print("and session found.\n");

			/* Send BYE ACK message. */
			acknowledgement.session_id = 0;
			acknowledgement.identifier = GINT32_TO_LE(mpsession->baseidentifier + mpsession->id_increment);
			/* msnp2p_inc(mpsession); */
			acknowledgement.offset = 0;
			acknowledgement.total_size = 0;
			acknowledgement.size = 0;
			acknowledgement.flags = GINT32_TO_LE(0x42);
			acknowledgement.ack_sess = mpheader->identifier;
			acknowledgement.ack_id = mpheader->ack_sess;
			acknowledgement.ack_size = mpheader->size;

			debug_print("MP: Sending BYE ACK\n");
			msnp2p_send(session, acknowledgement, mpsession->username, "", 0, 0);

			/* Delay before deletion allows straggling packets to be collected. */
			debug_print("MP: Closing MSNP2P session in ten seconds...\n");
			mpsession->delete_timeout = g_timeout_add(10000, (GSourceFunc)msnp2p_closesession, mpsession);

			return 1;

		}

	}

	return 0;

}

static unsigned int msnp2p_cookie() {

	FILE *fh;
	unsigned int seed;
	float num;
	unsigned int val;

	fh = fopen("/dev/urandom", "r");
	fread(&seed, sizeof(seed), 1, fh);
	fclose(fh);
	srand(seed);

	num = (float)rand() / (float)RAND_MAX;
	val = (num * 16777216)+8;

	return val;

}

static MpSession *msnp2p_send_dp(MpSession *mpsession, SbSession *session, const char *msnslp) {

	MpHeader msnp2p_binary;
	char *msnslp_block;
	size_t msnslp_length;
	glob_t glob_result;
	struct stat *statbuf;
	void *picture_data;
	unsigned int file_offs;
	int zero;
	struct stat stat_buffer;
	FILE *fh;
	unsigned int size;
	int readval;
	char *request_details;
	size_t request_details_length;
	char *local_avatar;

	mpsession->via = mime_getfield_anywhere(msnslp, "Via:");
	if ( mpsession->via == NULL ) {
		debug_print("MP: Couldn't find Via field.\n");
		free(mpsession);
		return NULL;
	}
	mpsession->call_id = mime_getfield_anywhere(msnslp, "Call-ID:");
	if ( mpsession->call_id == NULL ) {
		debug_print("MP: Couldn't find Call-ID field.\n");
		free(mpsession);
		return NULL;
	}

	request_details = malloc(26);
	debug_print("MP: New session ID=%i\n", mpsession->session_id);
	strcpy(request_details, "SessionID: ");
	sprintf(request_details+strlen(request_details), "%i\r\n\r\n", mpsession->session_id);
	request_details_length = strlen(request_details);

	msnslp_block = malloc( 176 + strlen(options_username()) + strlen(mpsession->username) + strlen(mpsession->via) + strlen(mpsession->call_id) + strlen(request_details) );
	strcpy(msnslp_block, "MSNSLP/1.0 200 OK\r\nTo: <msnmsgr:");
	strncat(msnslp_block, mpsession->username, 64);
	strcat(msnslp_block, ">\r\nFrom: <msnmsgr:");
	strncat(msnslp_block, options_username(), 64);
	strcat(msnslp_block, ">\r\nVia: ");
	strncat(msnslp_block, mpsession->via, 256);
	strcat(msnslp_block, "\r\nCSeq: 1 \r\nCall-ID: ");
	strncat(msnslp_block, mpsession->call_id, 256);
	strcat(msnslp_block, "\r\nMax-Forwards: 0\r\nContent-Type: application/x-msnmsgr-sessionreqbody\r\nContent-Length: ");
	assert(request_details_length + 1 < 10000);
	sprintf(msnslp_block+strlen(msnslp_block), "%i", request_details_length+1);
	strcat(msnslp_block, "\r\n\r\n");
	strcat(msnslp_block, request_details);
	free(request_details);

	msnslp_length = strlen(msnslp_block);

	msnp2p_binary.session_id = 0;
	msnp2p_binary.identifier = GINT32_TO_LE(mpsession->baseidentifier + mpsession->id_increment);
	msnp2p_inc(mpsession);
	msnp2p_binary.offset = 0;
	msnp2p_binary.total_size = GINT64_TO_LE(msnslp_length+1);
	msnp2p_binary.size = GINT64_TO_LE(msnslp_length+1);
	msnp2p_binary.flags = 0;
	msnp2p_binary.ack_sess = GINT32_TO_LE(mpsession->session_id);
	msnp2p_binary.ack_id = 0;
	msnp2p_binary.ack_size = 0;
	debug_print("MP: Sending 200 OK message\n");
	msnp2p_send(session, msnp2p_binary, mpsession->username, msnslp_block, strlen(msnslp_block)+1, 0);
	free(msnslp_block);

	local_avatar = avatars_local();
	glob(local_avatar, GLOB_TILDE, NULL, &glob_result);
	free(local_avatar);

	statbuf = &stat_buffer;
	if ( stat(glob_result.gl_pathv[0], statbuf) == -1 ) {
		debug_print("MP: Couldn't find avatar file :(\n");
		free(mpsession);
		return NULL;
	}

	size = (int)statbuf->st_size;
	assert(size > 0);

	fh = fopen(glob_result.gl_pathv[0], "r");
	if ( fh == NULL ) {
		debug_print("MP: Couldn't open avatar file.\n");
		free(mpsession);
		return NULL;
	}
	picture_data = malloc(size);
	readval = fread(picture_data, 1, size, fh);
	if ( readval < 0 ) {
		debug_print("MP: Couldn't read avatar file.\n");
		free(mpsession);
		free(picture_data);
		return NULL;
	}
	debug_print("MP: Read %i bytes of avatar file\n", readval);
	fclose(fh);
	globfree(&glob_result);

	msnp2p_binary.session_id = GINT32_TO_LE(mpsession->session_id);
	msnp2p_binary.identifier = GINT32_TO_LE(mpsession->baseidentifier + mpsession->id_increment);
	msnp2p_inc(mpsession);
	msnp2p_binary.offset = 0;
	msnp2p_binary.total_size = GINT64_TO_LE(4);
	msnp2p_binary.size = GINT64_TO_LE(4);
	msnp2p_binary.flags = 0;
	msnp2p_binary.ack_sess = GINT32_TO_LE(123456);
	msnp2p_binary.ack_id = 0;
	msnp2p_binary.ack_size = 0;
	zero = 0;
	debug_print("MP: Sending data preparation message\n");
	msnp2p_send(session, msnp2p_binary, mpsession->username, (char *)&zero, 4, 1);

	msnp2p_binary.session_id = GINT32_TO_LE(mpsession->session_id);
	msnp2p_binary.identifier = GINT32_TO_LE(mpsession->baseidentifier + mpsession->id_increment);
	msnp2p_inc(mpsession);
	msnp2p_binary.total_size = GINT64_TO_LE(size);
	msnp2p_binary.flags = GINT32_TO_LE(0x20);
	msnp2p_binary.ack_id = 0;
	msnp2p_binary.ack_size = 0;

	for ( file_offs=0; file_offs<size; file_offs+=1202 ) {

		msnp2p_binary.offset = file_offs;
		if ( (size-file_offs) > 1201 ) {
			msnp2p_binary.size = GINT64_TO_LE(1202);
		} else {
			msnp2p_binary.size = GINT64_TO_LE((size-file_offs) % 1202);
		}
		msnp2p_binary.ack_sess = msnp2p_cookie();
		debug_print("MP: Sending %i bytes: %i-%i of %i\n", msnp2p_binary.size, (int)msnp2p_binary.offset, (int)(msnp2p_binary.offset+msnp2p_binary.size)-1, (int)msnp2p_binary.total_size);
		msnp2p_send(session, msnp2p_binary, mpsession->username, picture_data+file_offs, msnp2p_binary.size, 1);

	}

	free(picture_data);

	return mpsession;

}

static MpSession *msnp2p_incomingsession(SbSession *session, const char *msnslp, MpHeader *mpheader) {

	MpSession *mpsession;
	char *temp_name;
	char *session_id_string;
	unsigned int session_id;
	MpHeader acknowledgement;
	char *euf_guid;
	char *content_type;

	if ( strncmp(msnslp, "INVITE MSNMSGR:", 15) != 0 ) {
		return NULL;
	}

	content_type = mime_getfield(msnslp, "Content-Type");
	if ( strcmp(content_type, "application/x-msnmsgr-transreqbody") == 0 ) {
	}
	free(content_type);

	session_id_string = mime_getfield_anywhere(msnslp, "SessionID:");
	if ( strlen(session_id_string) == 0 ) {
		debug_print("MP: Couldn't find SessionID field.\n");
		free(session_id_string);
		return NULL;
	}
	session_id = atoi(session_id_string);
	free(session_id_string);
	/* Return if this packet isn't to be dealt with here. */
	if ( session_id == 0 ) {
		return NULL;
	}

	euf_guid = mime_getfield_anywhere(msnslp, "EUF-GUID:");
	if ( strlen(euf_guid) == 0 ) {
		debug_print("MP: Couldn't find EUF-GUID field.\n");
		return NULL;
	}

	mpsession = msnp2p_new();
	if ( mpsession == NULL ) {
		debug_print("MP: Not enough memory to start MSNP2P transfer.\n");
		return NULL;
	}

	if ( strcmp(euf_guid, "{A4268EEC-FEC5-49E5-95C3-F126696BDBF6}") == 0 ) {
		mpsession->type = MSNP2P_TYPE_DP;
	} else if ( strcmp(euf_guid, "{5D3E02AB-6190-11D3-BBBB-00C04F795683}") == 0 ) {
		mpsession->type = MSNP2P_TYPE_FT;
	} else {
		debug_print("MP: Unrecognised MSNSLP INVITE.\n");
		free(euf_guid);
		return NULL;
	}
	free(euf_guid);

	mpsession->parent = session;
	mpsession->baseidentifier = msnp2p_cookie();
	mpsession->id_increment = -3;
	mpsession->session_id = session_id;
	mpsession->direction = MSNP2P_DIR_SEND;
	mpsession->save_filename = NULL;
	mpsession->sha1d = NULL;

	/* Get actual username. */
	temp_name = mime_getfield(msnslp, "From:");
	if ( temp_name == NULL ) {
		debug_print("MP: Couldn't find From field.\n");
		free(mpsession);
		return NULL;
	}
	if ( strncmp(temp_name, "<msnmsgr:", 9) != 0 ) {
		debug_print("MP: MSNSLP request not from \"<msnmsgr:*>\" - giving up.\n");
		free(mpsession);
		return NULL;
	}
	mpsession->username = strdup(temp_name+9);
	free(temp_name);
	if ( mpsession->username == NULL ) {
		debug_print("MP: Couldn't find From field.\n");
		free(mpsession);
		return NULL;
	}
	mpsession->username[strlen(mpsession->username)-1] = '\0';

	switch ( mpsession->type ) {
		case MSNP2P_TYPE_DP : debug_print("MP: Got Display Picture Invite from %s\n", mpsession->username); break;
		case MSNP2P_TYPE_FT : debug_print("MP: Got File Transfer Invite from %s\n", mpsession->username); break;
		case MSNP2P_TYPE_INK : debug_print("MP: This doesn't happen.\n"); break;
	}

	debug_print("MSNSLP: '%s'\n", msnslp);

	acknowledgement.session_id = 0;
	acknowledgement.identifier = GINT32_TO_LE(mpsession->baseidentifier);
	acknowledgement.offset = 0;
	acknowledgement.total_size = mpheader->total_size;
	acknowledgement.size = 0;
	acknowledgement.flags = GINT32_TO_LE(2);
	acknowledgement.ack_sess = mpheader->identifier;
	acknowledgement.ack_id = mpheader->ack_sess;
	acknowledgement.ack_size = mpheader->total_size;
	debug_print("MP: Sending BaseIdentifier message\n");
	msnp2p_send(session, acknowledgement, mpsession->username, "", 0, 0);

	if ( mpsession->type == MSNP2P_TYPE_DP ) {
		mpsession = msnp2p_send_dp(mpsession, session, msnslp);
	}

	if ( mpsession != NULL ) {
		msnp2p_list = g_list_append(msnp2p_list, mpsession);
	}

	return mpsession;

}

static void msnp2p_sendbye(SbSession *session, MpSession *mpsession) {

	char *msnslp_block;
	MpHeader mpheader;
	int msnslp_length;

	msnslp_block = malloc( 294 + 2*strlen(mpsession->username) + strlen(options_username()) );
	strcpy(msnslp_block, "BYE MSNMSGR:");
	strncat(msnslp_block, mpsession->username, 64);
	strcat(msnslp_block, " MSNSLP/1.0\r\nTo: <msnmsgr:");
	strncat(msnslp_block, mpsession->username, 64);
	strcat(msnslp_block, ">\r\nFrom: <msnmsgr:");
	strncat(msnslp_block, options_username(), 64);
	strcat(msnslp_block, ">\r\nVia: MSNSLP/1.0/TLP ;branch={33517CE4-02FC-4428-B6F4-39927229B722}\r\nCSeq: 0 \r\nCall-ID: ");
	strncat(msnslp_block, mpsession->call_id, 38);
	strcat(msnslp_block, "\r\nMax-Forwards: 0\r\nContent-Type: application/x-msnmsgr-sessionclosebody\r\nContent-Length: 3");
	strcat(msnslp_block, "\r\n\r\n");

	msnslp_length = strlen(msnslp_block);

	mpheader.session_id = 0;
	mpheader.identifier = GINT32_TO_LE(mpsession->baseidentifier + mpsession->id_increment);
	msnp2p_inc(mpsession);
	mpheader.offset = 0;
	mpheader.total_size = GINT64_TO_LE(msnslp_length+1);
	mpheader.size = GINT64_TO_LE(msnslp_length+1);
	mpheader.flags = 0;
	mpheader.ack_sess = GINT32_TO_LE(mpsession->session_id);
	mpheader.ack_id = 0;
	mpheader.ack_size = 0;

	debug_print("MP: Sending MSNSLP BYE for display picture.\n");
	msnp2p_send(session, mpheader, mpsession->username, msnslp_block, msnslp_length+1, 0);

	free(msnslp_block);

}

static void msnp2p_handledatapacket(SbSession *session, MpHeader *mpheader, MpSession *mpsession, const char *msnslp) {

	FILE *fh;

	debug_print("MP: Got data packet: %i-%i of %i\n", (int)mpheader->offset, (int)(mpheader->offset+mpheader->size)-1, (int)mpheader->total_size);

	fh = fopen(mpsession->save_filename, "a");
	if ( fh == NULL ) {
		debug_print("MP: Couldn't open avatar file to write data.\n");
		return;
	}
	fwrite(msnslp, 1, mpheader->size, fh);
	fclose(fh);

	/* Got all of data? */
	if ( mpheader->offset+mpheader->size >= mpheader->total_size ) {

		/* Send an acknowledgement for the data */
		MpHeader acknowledgement;

		acknowledgement.session_id = mpheader->session_id;
		acknowledgement.identifier = GINT32_TO_LE(mpsession->baseidentifier + mpsession->id_increment);
		msnp2p_inc(mpsession);
		acknowledgement.offset = 0;
		acknowledgement.total_size = 0;
		acknowledgement.size = 0;
		acknowledgement.flags = GINT32_TO_LE(2);
		acknowledgement.ack_sess = mpheader->session_id;
		acknowledgement.ack_id = mpheader->identifier;
		acknowledgement.ack_size = mpheader->total_size;

		msnp2p_send(session, acknowledgement, mpsession->username, "", 0, 0);

		msnp2p_sendbye(session, mpsession);
		contactlist_picturekick_sha1d(mpsession->sha1d);

		/* Delay before deletion allows straggling packets to be collected. */
		debug_print("MP: Closing MSNP2P session in ten seconds...\n");
		mpsession->delete_timeout = g_timeout_add(10000, (GSourceFunc)msnp2p_closesession, mpsession);

	}

}

static MpSession *msnp2p_check_ink(SbSession *session, const char *username, MpHeader *header, const void *data, unsigned long int app_id) {

	MpSession *mpsession;
	size_t datalength = GINT32_TO_LE(header->size);

	if ( !(header->session_id == 64) || !(app_id == 3) ) {
		return NULL;
	}

	debug_print("MP: Ink packet from '%s'\n", username);

	if ( header->offset == 0 ) {


		debug_print("MP: First in a sequence of Ink packets.\n");
		mpsession = msnp2p_new();

		mpsession->baseidentifier = GINT32_TO_LE(header->identifier);
		mpsession->type = MSNP2P_TYPE_INK;
		mpsession->direction = MSNP2P_DIR_RECV;
		mpsession->parent = session;
		mpsession->username = strdup(username);
		mpsession->session_id = 0;
		mpsession->via = NULL;
		mpsession->save_filename = NULL;
		mpsession->sha1d = NULL;
		mpsession->call_id = NULL;

		if ( datalength <= 2000 ) {	/* Sanity check */

			mpsession->data = malloc(datalength);
			memcpy(mpsession->data, data, datalength);
			mpsession->offset = datalength;

		} else {

			debug_print("MP: Ink packet too big - binning.\n");
			free(mpsession);
			return NULL;

		}

		msnp2p_list = g_list_append(msnp2p_list, mpsession);

	} else {

		mpsession = msnp2p_find_identifier(GINT32_TO_LE(header->identifier));
		if ( mpsession == NULL ) {
			debug_print("MP: Unrecognised Ink packet.\n");
			return NULL;
		}

		if ( datalength <= 2000 ) {

			mpsession->data = realloc(mpsession->data, (mpsession->offset) + datalength);
			if ( mpsession->data == NULL ) {
				debug_print("MP: Whoops! Couldn't allocate memory.\n");
				return NULL;
			}
			memcpy((mpsession->data)+(mpsession->offset), data, datalength);
			mpsession->offset += datalength;
			debug_print("MP: Got some continuing Ink data.\n");

		} else {
			debug_print("MP: Ink packet too big - binning.\n");
			return NULL;
		}


	}

	assert(mpsession != NULL);

	/* NB It's possible for a single message to be both the first and last in a sequence. */
	debug_print("MP: %i of %i bytes.\n", GINT64_TO_LE(header->offset), GINT64_TO_LE(header->total_size));
	if ( GINT64_TO_LE(header->offset) >= GINT64_TO_LE(header->total_size) ) {

		gchar *body;
		glong new_length;
		glong items_in;
		GError *error;

		debug_print("MP: Last in a sequence of Ink packets.\n");

		debug_print("MP: Decoding UTF-16: %i bytes in.\n", mpsession->offset);
		body = g_utf16_to_utf8(mpsession->data, mpsession->offset, &items_in, &new_length, &error);
		debug_print("MP: %i items in, %i items out.\n", items_in, new_length);
		if ( error == NULL ) {
			debug_print("MP: No error.\n");
		} else {
			debug_print("MP: Error!\n");
			debug_print("%s'\n", error->message);
		}
		if ( body == NULL ) {
			debug_print("MP: Conversion to UTF-8 failed: '%s'\n", error->message);
		} else {
			sbprotocol_parsemsg(session, body, new_length);
			debug_print("MP: Ink (%i bytes): '%s'\n", new_length, body);
			g_free(body);
		}

		debug_print("MP: Closing MSNP2P session in ten seconds...\n");
		mpsession->delete_timeout = g_timeout_add(10000, (GSourceFunc)msnp2p_closesession, mpsession);

	}

	return mpsession;

}

void msnp2p_parsemsg(SbSession *session, const char *username, const char *whole_msg, size_t len) {

	char *p2p_dest;
	MpSession *mpsession;
	MpHeader *mpheader;
	const char *msnslp;
	const char *msg;
	unsigned long int app_id;

	/* First check the destination of the message and ignore if appropriate. */
	p2p_dest = mime_getfield(whole_msg, "P2P-Dest");
	if ( p2p_dest == NULL ) {
		debug_print("MP: Couldn't find P2P-Dest field.\n");
		return;
	}
	if ( strcasecmp(options_username(), p2p_dest) != 0 ) {
		free(p2p_dest);
		debug_print("MP: Ignoring misaddressed MSNP2P message.\n");
		return;
	}
	free(p2p_dest);

	/* Now forget about the MIME header. */
	len -= mime_headerlength(whole_msg);
	msg = mime_getbody(whole_msg);
	mpheader = (MpHeader *)msg;		/* First bytes of "msg" are the header. Obviously. */
	msnslp = msg+sizeof(MpHeader);		/* Contents */

	/* Check the provided packet size is sane. */
	if ( len < GINT64_TO_LE(mpheader->size) ) {
		debug_print("MP: 'size' field in header too big - rejecting packet.\n");
		return;
	}
	app_id = ntohl(*(int *)(msg+(mpheader->size)+48));

#ifdef MSNP2P_DEBUG
	debug_print("MP: ---- MSNP2P packet ----\n");
	debug_print("MP:  sessionid = 0x%lx\n", mpheader->session_id);
	debug_print("MP: identifier = 0x%lx\n", mpheader->identifier);
	debug_print("MP:     offset = 0x%llx\n", mpheader->offset);
	debug_print("MP: total_size = 0x%llx\n", mpheader->total_size);
	debug_print("MP:       size = 0x%lx\n", mpheader->size);
	debug_print("MP:      flags = 0x%lx\n", mpheader->flags);
	debug_print("MP:     ack_id = 0x%lx\n", mpheader->ack_id);
	debug_print("MP:   ack_sess = 0x%lx\n", mpheader->ack_sess);
	debug_print("MP:   ack_size = 0x%llx\n", mpheader->ack_size);
	debug_print("MP:     app_id = 0x%lx\n", app_id);
#endif	/* MSNP2P_DEBUG */

	/* Arrrggggggggggghhhhhhhhhhhhhhhhhhhhhh. */
	mpsession = msnp2p_find_identifier(GINT32_TO_LE(mpheader->ack_sess));
	if ( mpsession == NULL ) {
		mpsession = msnp2p_find_sessionid(GINT32_TO_LE(mpheader->session_id));
	}
	if ( mpsession == NULL ) {
		mpsession = msnp2p_check_ok(msnslp);
	}
	if ( mpsession == NULL ) {
		mpsession = msnp2p_find_sessionid(GINT32_TO_LE(mpheader->ack_id));
	}
	if ( (mpsession == NULL) && (mpheader->session_id == 0) ) {
		mpsession = msnp2p_incomingsession(session, msnslp, mpheader);
	}
	if ( msnp2p_check_bye(session, msnslp, mpheader) != 0 ) {
		debug_print("MP: Got BYE.\n");
		return;
	}
	if ( mpsession == NULL ) {
		mpsession = msnp2p_check_ink(session, username, mpheader, msnslp, app_id);
	}

	/* Past this point, if the message hasn't been matched to a session then it's unrecognised. */

	if ( mpsession == NULL ) {
		debug_print("MP: Unrecognised MSNP2P ");
		if ( (GINT32_TO_LE(mpheader->flags) & 2) != 0 ) {
			debug_print("ack.\n");
		} else {
			debug_print("packet:\n");
			debug_print("MP: Flags = %x\n", GINT32_TO_LE(mpheader->flags));
			debug_print("MP: Data: '%s'\n", msnslp);
		}
		return;
	}

	if ( ( GINT32_TO_LE(mpheader->flags) & 2) != 0 ) {
		debug_print("MP: Got ACK.\n");
	}

	if ( ( (GINT32_TO_LE(mpheader->flags) & 2) == 0) && (mpheader->size == mpheader->total_size) ) {

		/* Message wasn't an ACK, so probably needs an ACK sending */

		MpHeader acknowledgement;

		acknowledgement.session_id = GINT32_TO_LE(mpheader->session_id);
		acknowledgement.identifier = GINT32_TO_LE(mpsession->baseidentifier + mpsession->id_increment);
	/*	msnp2p_inc(mpsession);	*/
		acknowledgement.offset = 0;
		acknowledgement.total_size = 0;
		acknowledgement.size = 0;
		if ( GINT32_TO_LE(mpheader->flags) == 0x40 ) {
			acknowledgement.flags = GINT32_TO_LE(0x80);
		} else {
			acknowledgement.flags = GINT32_TO_LE(2);
		}
		/* Copying directly from received header: don't touch endianness. */
		acknowledgement.ack_sess = mpheader->session_id;
		acknowledgement.ack_id = mpheader->identifier;
		acknowledgement.ack_size = mpheader->size;

		debug_print("MP: Sending ACK.\n");
		msnp2p_send(session, acknowledgement, mpsession->username, "", 0, 0);

	}

	if ( (app_id == 1) && (GINT64_TO_LE(mpheader->total_size) != 4) ) {
		msnp2p_handledatapacket(session, mpheader, mpsession, msnslp);
	}

}

/* Check for a receive session for the DP SHA1D given. */
int msnp2p_retrieving(const char *save_filename) {

	GList *result = NULL;

	result = g_list_find_custom(msnp2p_list, save_filename, (GCompareFunc)msnp2p_compare_savefilename);
	if ( result != NULL ) {
		/* At least one session exists.  Don't care what it is... */
		return 1;
	}

	/* Nothing found. */
	return 0;

}

/* Initiate the downloading of a picture. */
void msnp2p_getpicture(SbSession *session, const char *username, const char *dpobject) {

	MpSession *mpsession;
	MpHeader mpheader;

	char *dpobject_decoded;
	char *context;
	char *data_hash;
	char *filename;

	char *request_details;
	int request_details_length;
	char *request_details_length_string;
	char *msnslp_block;
	int msnslp_length;
	glob_t glob_result;
	struct stat stat_buffer;
	struct stat *statbuf;

	debug_print("MP: Beginning download for DP from '%s'\n", username);

	assert(username != NULL);
	assert(session != NULL);

	if ( dpobject == NULL ) {
		debug_print("MP: Attempt to download avatar for user who doesn't have one.\n");
		return;
	}

	if ( sbsessions_sessionready(session) == 0 ) {
		debug_print("MP: Session isn't ready to download picture - not trying.\n");
		return;
	}

	mpsession = msnp2p_new();
	if ( mpsession == NULL ) {
		debug_print("MP: Not enough memory to do picture request - giving up.\n");
		return;
	}

	mpsession->parent = session;
	mpsession->baseidentifier = msnp2p_cookie();
	mpsession->session_id = msnp2p_cookie();
	mpsession->direction = MSNP2P_DIR_RECV;
	mpsession->id_increment = -3;
	mpsession->call_id = routines_guid();
	mpsession->via = NULL;

	debug_print("MP: Generated: Session ID '%i', BaseIdentifier '%i', Call-ID '%s'.\n", mpsession->session_id, mpsession->baseidentifier, mpsession->call_id);

	/* urldecode() the MSNObject and then base64 it to get the "Context" field,
		then retrieve the "SHA1D" field from the (urldecoded) MSNObject to generate
		the filename to save to. */
	dpobject_decoded = routines_urldecode(dpobject);
	context = routines_base64(dpobject_decoded);
	data_hash = xml_getfield(dpobject_decoded, "SHA1D");
	debug_print("MP: Got data hash: %s\n", data_hash);
	free(dpobject_decoded);
	filename = xml_killillegalchars(data_hash);
	mpsession->sha1d = data_hash;	/* Don't free this yet. */

	/* Determine the full filename to save to. */
	glob("~", GLOB_TILDE, NULL, &glob_result);
	mpsession->save_filename = malloc(strlen(filename)+strlen("/.tuxmessenger/avatars/")+strlen(glob_result.gl_pathv[0]) + 1);
	if ( mpsession->save_filename == NULL ) {

		debug_print("MP: Not enough memory to do picture request - giving up.\n");
		free(mpsession->call_id);
		free(mpsession);
		return;

	}
	strcpy(mpsession->save_filename, glob_result.gl_pathv[0]);
	strcat(mpsession->save_filename, "/.tuxmessenger/avatars/");
	strcat(mpsession->save_filename, filename);
	globfree(&glob_result);
	free(filename);

	/* Check to see there isn't already a receive session going on for this user. */

	if ( msnp2p_retrieving(mpsession->save_filename) != 0 ) {

		debug_print("MP: A DP receive session is already in progress to '%s' - not starting a new one.\n", mpsession->save_filename);
		free(mpsession->call_id);
		free(mpsession);
		return;

	}

	/* Check if we already have this picture or not */
	statbuf = &stat_buffer;
	if ( stat(mpsession->save_filename, statbuf) != -1 ) {

		/* messagewindow_trypicture should have worked this out before. */
		debug_print("MP: Already have this picture: %s\n", mpsession->save_filename);
		free(mpsession->save_filename);
		free(mpsession->call_id);
		free(mpsession);
		return;

	}

	/* Silly preliminaries out of the way.  Time to do the request... */

	/* Create the payload for the MSNSLP request */
	request_details = malloc( 96 + strlen(context) + 9 );
	if ( request_details == NULL ) {

		debug_print("MP: Not enough memory to do picture request - giving up.\n");
		free(mpsession->save_filename);
		free(mpsession->call_id);
		free(mpsession);
		return;

	}
	strcpy(request_details, "EUF-GUID: {A4268EEC-FEC5-49E5-95C3-F126696BDBF6}\r\nSessionID: ");
	/* Check we're not about to screw ourselves over.  8 bytes were allowed
		above to fit the sessionid into. */
	if ( mpsession->session_id > 99999999 ) {

		debug_print("MP: SessionID is too big - giving up.\n");
		free(request_details);
		free(mpsession->save_filename);
		free(mpsession->call_id);
		free(mpsession);
		return;

	}
	sprintf(request_details+strlen(request_details), "%i", mpsession->session_id);
	strcat(request_details, "\r\nAppID: 1\r\nContext: ");
	strcat(request_details, context);
	free(context);
	strcat(request_details, "\r\n\r\n");
	request_details_length = strlen(request_details);

	request_details_length_string = malloc(5);
	assert(request_details_length < 9998);	/* Sanity check. */
	sprintf(request_details_length_string, "%i", request_details_length+1);

	/* Now create the MSNSLP request itself */
	msnslp_block = malloc( 291 + (2*strlen(username)) + strlen(options_username()) + strlen(request_details) + strlen(request_details_length_string) );
	strcpy(msnslp_block, "INVITE MSNMSGR:");
	strncat(msnslp_block, username, 64);
	strcat(msnslp_block, " MSNSLP/1.0\r\nTo: <msnmsgr:");
	strncat(msnslp_block, username, 64);
	strcat(msnslp_block, ">\r\nFrom: <msnmsgr:");
	strncat(msnslp_block, options_username(), 64);
	strcat(msnslp_block, ">\r\nVia: MSNSLP/1.0/TLP ;branch={33517CE4-02FC-4428-B6F4-39927229B722}\r\nCSeq: 0 \r\nCall-ID: ");
	strncat(msnslp_block, mpsession->call_id, 38);
	strcat(msnslp_block, "\r\nMax-Forwards: 0\r\nContent-Type: application/x-msnmsgr-sessionreqbody\r\nContent-Length: ");
	strncat(msnslp_block, request_details_length_string, 30);
	free(request_details_length_string);
	strcat(msnslp_block, "\r\n\r\n");
	strcat(msnslp_block, request_details);
	free(request_details);
	msnslp_length = strlen(msnslp_block);

	debug_print("MP: Sending MSNSLP INVITE for display picture.\n");

	/* Now wrap it up with the MSNP2P rubbish */
	mpheader.session_id = 0;
	mpheader.identifier = GINT32_TO_LE(mpsession->baseidentifier + mpsession->id_increment);
	msnp2p_inc(mpsession);
	mpheader.offset = 0;
	mpheader.total_size = GINT64_TO_LE(msnslp_length+1);
	mpheader.size = GINT64_TO_LE(msnslp_length+1);
	mpheader.flags = 0;
	mpheader.ack_sess = GINT32_TO_LE(mpsession->session_id);
	mpheader.ack_id = 0;
	mpheader.ack_size = 0;

	msnp2p_send(session, mpheader, username, msnslp_block, strlen(msnslp_block)+1, 0);

	free(msnslp_block);

	mpsession->username = strdup(username);
	msnp2p_list = g_list_append(msnp2p_list, mpsession);

}

/* Bin all the MSNP2P/MSNSLP sessions in a given switchboard session. */
void msnp2p_abortall(SbSession *session) {

	GList *result;

	result = g_list_find_custom(msnp2p_list, &session, (GCompareFunc)msnp2p_compare_parent);

	while ( result != NULL ) {

		MpSession *mpsession;
		mpsession = result->data;
		msnp2p_closesession(mpsession);

		result = g_list_find_custom(msnp2p_list, &session, (GCompareFunc)msnp2p_compare_parent);

	}

}

void msnp2p_offerfile(SbSession *session, const char *username, const char *filename) {

	MpSession *mpsession;
	MpHeader mpheader;
	char *context;
	char *request_details;
	size_t request_details_length;
	char *request_details_length_string;
	char *msnslp_block;
	size_t msnslp_length;

	assert(session != NULL);
	assert(username != NULL);
	assert(filename != NULL);

	mpsession = msnp2p_new();
	if ( mpsession == NULL ) {
		debug_print("MP: Not enough memory to send file - giving up.\n");
		return;
	}

	mpsession->parent = session;
	mpsession->baseidentifier = msnp2p_cookie();
	mpsession->session_id = msnp2p_cookie();
	mpsession->direction = MSNP2P_DIR_SEND;
	mpsession->id_increment = 0;
	mpsession->call_id = routines_guid();
	mpsession->via = NULL;

	context = strdup("WIBBLE!!!112");	/* File preview data... */

	debug_print("MP: Generated: Session ID '%i', BaseIdentifier '%i', Call-ID '%s'.\n", mpsession->session_id, mpsession->baseidentifier, mpsession->call_id);

	/* Create the payload for the MSNSLP request */
	request_details = malloc( 96 + strlen(context) + 9 );
	if ( request_details == NULL ) {

		debug_print("MP: Not enough memory to do picture request - giving up.\n");
		free(mpsession->save_filename);
		free(mpsession->call_id);
		free(mpsession);
		return;

	}
	strcpy(request_details, "EUF-GUID: {5D3E02AB-6190-11D3-BBBB-00C04F795683}\r\nSessionID: ");
	/* Check we're not about to screw ourselves over.  8 bytes were allowed
		above to fit the sessionid into. */
	if ( mpsession->session_id > 99999999 ) {

		debug_print("MP: SessionID is too big - giving up.\n");
		free(request_details);
		free(mpsession->call_id);
		free(mpsession);
		return;

	}
	sprintf(request_details+strlen(request_details), "%i", mpsession->session_id);
	strcat(request_details, "\r\nAppID: 1\r\nContext: ");
	strcat(request_details, context);
	free(context);
	strcat(request_details, "\r\n\r\n");
	request_details_length = strlen(request_details);

	request_details_length_string = malloc(5);
	assert(request_details_length < 9998);	/* Sanity check. */
	sprintf(request_details_length_string, "%i", request_details_length+1);

	/* Now create the MSNSLP request itself */
	msnslp_block = malloc( 291 + (2*strlen(username)) + strlen(options_username()) + strlen(request_details) + strlen(request_details_length_string) );
	strcpy(msnslp_block, "INVITE MSNMSGR:");
	strncat(msnslp_block, username, 64);
	strcat(msnslp_block, " MSNSLP/1.0\r\nTo: <msnmsgr:");
	strncat(msnslp_block, username, 64);
	strcat(msnslp_block, ">\r\nFrom: <msnmsgr:");
	strncat(msnslp_block, options_username(), 64);
	strcat(msnslp_block, ">\r\nVia: MSNSLP/1.0/TLP ;branch={33517CE4-02FC-4428-B6F4-39927229B722}\r\nCSeq: 0 \r\nCall-ID: ");
	strncat(msnslp_block, mpsession->call_id, 38);
	strcat(msnslp_block, "\r\nMax-Forwards: 0\r\nContent-Type: application/x-msnmsgr-sessionreqbody\r\nContent-Length: ");
	strncat(msnslp_block, request_details_length_string, 30);
	free(request_details_length_string);
	strcat(msnslp_block, "\r\n\r\n");
	strcat(msnslp_block, request_details);
	free(request_details);
	msnslp_length = strlen(msnslp_block);

	debug_print("MP: Sending MSNSLP INVITE for file transfer...\n");

	/* Now wrap it up with the MSNP2P rubbish */
	mpheader.session_id = 0;
	mpheader.identifier = GINT32_TO_LE(mpsession->baseidentifier + mpsession->id_increment);
	msnp2p_inc(mpsession);
	mpheader.offset = 0;
	mpheader.total_size = GINT64_TO_LE(msnslp_length+1);
	mpheader.size = GINT64_TO_LE(msnslp_length+1);
	mpheader.flags = 0;
	mpheader.ack_sess = GINT32_TO_LE(mpsession->session_id);
	mpheader.ack_id = 0;
	mpheader.ack_size = 0;

	msnp2p_send(session, mpheader, username, msnslp_block, strlen(msnslp_block)+1, 0);

	free(msnslp_block);

	mpsession->username = strdup(username);
	msnp2p_list = g_list_append(msnp2p_list, mpsession);

}