[linux.git] / net / x25 / x25_facilities.c

/*
 *	X.25 Packet Layer release 002
 *
 *	This is ALPHA test software. This code may break your machine,
 *	randomly fail to work with new releases, misbehave and/or generally
 *	screw up. It might even work. 
 *
 *	This code REQUIRES 2.1.15 or higher
 *
 *	This module:
 *		This module 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 (at your option) any later version.
 *
 *	History
 *	X.25 001	Split from x25_subr.c
 *	mar/20/00	Daniela Squassoni Disabling/enabling of facilities 
 *					  negotiation.
 *	apr/14/05	Shaun Pereira - Allow fast select with no restriction
 *					on response.
 */

#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/skbuff.h>
#include <net/sock.h>
#include <net/x25.h>

/*
 * Parse a set of facilities into the facilities structures. Unrecognised
 *	facilities are written to the debug log file.
 */
int x25_parse_facilities(struct sk_buff *skb, struct x25_facilities *facilities,
		struct x25_dte_facilities *dte_facs, unsigned long *vc_fac_mask)
{
	unsigned char *p = skb->data;
	unsigned int len = *p++;

	*vc_fac_mask = 0;

	/*
	 * The kernel knows which facilities were set on an incoming call but
	 * currently this information is not available to userspace.  Here we
	 * give userspace who read incoming call facilities 0 length to indicate
	 * it wasn't set.
	 */
	dte_facs->calling_len = 0;
	dte_facs->called_len = 0;
	memset(dte_facs->called_ae, '\0', sizeof(dte_facs->called_ae));
	memset(dte_facs->calling_ae, '\0', sizeof(dte_facs->calling_ae));

	while (len > 0) {
		switch (*p & X25_FAC_CLASS_MASK) {
		case X25_FAC_CLASS_A:
			switch (*p) {
			case X25_FAC_REVERSE:
				if((p[1] & 0x81) == 0x81) {
					facilities->reverse = p[1] & 0x81;
					*vc_fac_mask |= X25_MASK_REVERSE;
					break;
				}

				if((p[1] & 0x01) == 0x01) {
					facilities->reverse = p[1] & 0x01;
					*vc_fac_mask |= X25_MASK_REVERSE;
					break;
				}

				if((p[1] & 0x80) == 0x80) {
					facilities->reverse = p[1] & 0x80;
					*vc_fac_mask |= X25_MASK_REVERSE;
					break;
				}

				if(p[1] == 0x00) {
					facilities->reverse
						= X25_DEFAULT_REVERSE;
					*vc_fac_mask |= X25_MASK_REVERSE;
					break;
				}

			case X25_FAC_THROUGHPUT:
				facilities->throughput = p[1];
				*vc_fac_mask |= X25_MASK_THROUGHPUT;
				break;
			case X25_MARKER:
				break;
			default:
				printk(KERN_DEBUG "X.25: unknown facility "
				       "%02X, value %02X\n",
				       p[0], p[1]);
				break;
			}
			p   += 2;
			len -= 2;
			break;
		case X25_FAC_CLASS_B:
			switch (*p) {
			case X25_FAC_PACKET_SIZE:
				facilities->pacsize_in  = p[1];
				facilities->pacsize_out = p[2];
				*vc_fac_mask |= X25_MASK_PACKET_SIZE;
				break;
			case X25_FAC_WINDOW_SIZE:
				facilities->winsize_in  = p[1];
				facilities->winsize_out = p[2];
				*vc_fac_mask |= X25_MASK_WINDOW_SIZE;
				break;
			default:
				printk(KERN_DEBUG "X.25: unknown facility "
				       "%02X, values %02X, %02X\n",
				       p[0], p[1], p[2]);
				break;
			}
			p   += 3;
			len -= 3;
			break;
		case X25_FAC_CLASS_C:
			printk(KERN_DEBUG "X.25: unknown facility %02X, "
			       "values %02X, %02X, %02X\n",
			       p[0], p[1], p[2], p[3]);
			p   += 4;
			len -= 4;
			break;
		case X25_FAC_CLASS_D:
			switch (*p) {
	 		case X25_FAC_CALLING_AE:
	 			if (p[1] > X25_MAX_DTE_FACIL_LEN)
					break;
				dte_facs->calling_len = p[2];
				memcpy(dte_facs->calling_ae, &p[3], p[1] - 1);
				*vc_fac_mask |= X25_MASK_CALLING_AE;
				break;
			case X25_FAC_CALLED_AE:
				if (p[1] > X25_MAX_DTE_FACIL_LEN)
					break;
				dte_facs->called_len = p[2];
				memcpy(dte_facs->called_ae, &p[3], p[1] - 1);
				*vc_fac_mask |= X25_MASK_CALLED_AE;
				break;
			default:
				printk(KERN_DEBUG "X.25: unknown facility %02X,"
					"length %d, values %02X, %02X, "
					"%02X, %02X\n",
					p[0], p[1], p[2], p[3], p[4], p[5]);
				break;
			}
			len -= p[1] + 2;
			p += p[1] + 2;
			break;
		}
	}

	return p - skb->data;
}

/*
 *	Create a set of facilities.
 */
int x25_create_facilities(unsigned char *buffer,
		struct x25_facilities *facilities,
		struct x25_dte_facilities *dte_facs, unsigned long facil_mask)
{
	unsigned char *p = buffer + 1;
	int len;

	if (!facil_mask) {
		/*
		 * Length of the facilities field in call_req or
		 * call_accept packets
		 */
		buffer[0] = 0;
		len = 1; /* 1 byte for the length field */
		return len;
	}

	if (facilities->reverse && (facil_mask & X25_MASK_REVERSE)) {
		*p++ = X25_FAC_REVERSE;
		*p++ = facilities->reverse;
	}

	if (facilities->throughput && (facil_mask & X25_MASK_THROUGHPUT)) {
		*p++ = X25_FAC_THROUGHPUT;
		*p++ = facilities->throughput;
	}

	if ((facilities->pacsize_in || facilities->pacsize_out) &&
	    (facil_mask & X25_MASK_PACKET_SIZE)) {
		*p++ = X25_FAC_PACKET_SIZE;
		*p++ = facilities->pacsize_in ? : facilities->pacsize_out;
		*p++ = facilities->pacsize_out ? : facilities->pacsize_in;
	}

	if ((facilities->winsize_in || facilities->winsize_out) &&
	    (facil_mask & X25_MASK_WINDOW_SIZE)) {
		*p++ = X25_FAC_WINDOW_SIZE;
		*p++ = facilities->winsize_in ? : facilities->winsize_out;
		*p++ = facilities->winsize_out ? : facilities->winsize_in;
	}

	if (facil_mask & (X25_MASK_CALLING_AE|X25_MASK_CALLED_AE)) {
		*p++ = X25_MARKER;
		*p++ = X25_DTE_SERVICES;
	}

	if (dte_facs->calling_len && (facil_mask & X25_MASK_CALLING_AE)) {
		unsigned bytecount = (dte_facs->calling_len % 2) ?
					dte_facs->calling_len / 2 + 1 :
					dte_facs->calling_len / 2;
		*p++ = X25_FAC_CALLING_AE;
		*p++ = 1 + bytecount;
		*p++ = dte_facs->calling_len;
		memcpy(p, dte_facs->calling_ae, bytecount);
		p += bytecount;
	}

	if (dte_facs->called_len && (facil_mask & X25_MASK_CALLED_AE)) {
		unsigned bytecount = (dte_facs->called_len % 2) ?
		dte_facs->called_len / 2 + 1 :
		dte_facs->called_len / 2;
		*p++ = X25_FAC_CALLED_AE;
		*p++ = 1 + bytecount;
		*p++ = dte_facs->called_len;
		memcpy(p, dte_facs->called_ae, bytecount);
		p+=bytecount;
	}

	len       = p - buffer;
	buffer[0] = len - 1;

	return len;
}

/*
 *	Try to reach a compromise on a set of facilities.
 *
 *	The only real problem is with reverse charging.
 */
int x25_negotiate_facilities(struct sk_buff *skb, struct sock *sk,
		struct x25_facilities *new, struct x25_dte_facilities *dte)
{
	struct x25_sock *x25 = x25_sk(sk);
	struct x25_facilities *ours = &x25->facilities;
	struct x25_facilities theirs;
	int len;

	memset(&theirs, 0, sizeof(theirs));
	memcpy(new, ours, sizeof(*new));

	len = x25_parse_facilities(skb, &theirs, dte, &x25->vc_facil_mask);

	/*
	 *	They want reverse charging, we won't accept it.
	 */
	if ((theirs.reverse & 0x01 ) && (ours->reverse & 0x01)) {
		SOCK_DEBUG(sk, "X.25: rejecting reverse charging request");
		return -1;
	}

	new->reverse = theirs.reverse;

	if (theirs.throughput) {
		if (theirs.throughput < ours->throughput) {
			SOCK_DEBUG(sk, "X.25: throughput negotiated down");
			new->throughput = theirs.throughput;
		}
	}

	if (theirs.pacsize_in && theirs.pacsize_out) {
		if (theirs.pacsize_in < ours->pacsize_in) {
			SOCK_DEBUG(sk, "X.25: packet size inwards negotiated down");
			new->pacsize_in = theirs.pacsize_in;
		}
		if (theirs.pacsize_out < ours->pacsize_out) {
			SOCK_DEBUG(sk, "X.25: packet size outwards negotiated down");
			new->pacsize_out = theirs.pacsize_out;
		}
	}

	if (theirs.winsize_in && theirs.winsize_out) {
		if (theirs.winsize_in < ours->winsize_in) {
			SOCK_DEBUG(sk, "X.25: window size inwards negotiated down");
			new->winsize_in = theirs.winsize_in;
		}
		if (theirs.winsize_out < ours->winsize_out) {
			SOCK_DEBUG(sk, "X.25: window size outwards negotiated down");
			new->winsize_out = theirs.winsize_out;
		}
	}

	return len;
}

/*
 *	Limit values of certain facilities according to the capability of the 
 *      currently attached x25 link.
 */
void x25_limit_facilities(struct x25_facilities *facilities,
			  struct x25_neigh *nb)
{

	if (!nb->extended) {
		if (facilities->winsize_in  > 7) {
			printk(KERN_DEBUG "X.25: incoming winsize limited to 7\n");
			facilities->winsize_in = 7;
		}
		if (facilities->winsize_out > 7) {
			facilities->winsize_out = 7;
			printk( KERN_DEBUG "X.25: outgoing winsize limited to 7\n");
		}
	}
}
Commit	Line	Data
1da177e4 LT	1	/*
	2	* X.25 Packet Layer release 002
	3	*
	4	* This is ALPHA test software. This code may break your machine,
	5	* randomly fail to work with new releases, misbehave and/or generally
	6	* screw up. It might even work.
	7	*
	8	* This code REQUIRES 2.1.15 or higher
	9	*
	10	* This module:
	11	* This module is free software; you can redistribute it and/or
	12	* modify it under the terms of the GNU General Public License
	13	* as published by the Free Software Foundation; either version
	14	* 2 of the License, or (at your option) any later version.
	15	*
	16	* History
	17	* X.25 001 Split from x25_subr.c
	18	* mar/20/00 Daniela Squassoni Disabling/enabling of facilities
	19	* negotiation.
ebc3f64b SP	20	* apr/14/05 Shaun Pereira - Allow fast select with no restriction
ebc3f64b SP	21	* on response.
1da177e4 LT	22	*/
	23
	24	#include <linux/kernel.h>
	25	#include <linux/string.h>
	26	#include <linux/skbuff.h>
	27	#include <net/sock.h>
	28	#include <net/x25.h>
	29
	30	/*
a64b7b93	31	* Parse a set of facilities into the facilities structures. Unrecognised
1da177e4 LT	32	* facilities are written to the debug log file.
1da177e4 LT	33	*/
a64b7b93 SP	34	int x25_parse_facilities(struct sk_buff skb, struct x25_facilities facilities,
a64b7b93 SP	35	struct x25_dte_facilities dte_facs, unsigned long vc_fac_mask)
1da177e4 LT	36	{
	37	unsigned char *p = skb->data;
	38	unsigned int len = *p++;
	39
	40	*vc_fac_mask = 0;
	41
a64b7b93 SP	42	/*
	43	* The kernel knows which facilities were set on an incoming call but
	44	* currently this information is not available to userspace. Here we
	45	* give userspace who read incoming call facilities 0 length to indicate
	46	* it wasn't set.
	47	*/
	48	dte_facs->calling_len = 0;
	49	dte_facs->called_len = 0;
	50	memset(dte_facs->called_ae, '\0', sizeof(dte_facs->called_ae));
	51	memset(dte_facs->calling_ae, '\0', sizeof(dte_facs->calling_ae));
	52
1da177e4 LT	53	while (len > 0) {
	54	switch (*p & X25_FAC_CLASS_MASK) {
	55	case X25_FAC_CLASS_A:
	56	switch (*p) {
	57	case X25_FAC_REVERSE:
ebc3f64b SP	58	if((p[1] & 0x81) == 0x81) {
	59	facilities->reverse = p[1] & 0x81;
	60	*vc_fac_mask \|= X25_MASK_REVERSE;
	61	break;
	62	}
	63
	64	if((p[1] & 0x01) == 0x01) {
	65	facilities->reverse = p[1] & 0x01;
	66	*vc_fac_mask \|= X25_MASK_REVERSE;
	67	break;
	68	}
	69
	70	if((p[1] & 0x80) == 0x80) {
	71	facilities->reverse = p[1] & 0x80;
	72	*vc_fac_mask \|= X25_MASK_REVERSE;
	73	break;
	74	}
	75
	76	if(p[1] == 0x00) {
	77	facilities->reverse
	78	= X25_DEFAULT_REVERSE;
	79	*vc_fac_mask \|= X25_MASK_REVERSE;
	80	break;
	81	}
	82
1da177e4 LT	83	case X25_FAC_THROUGHPUT:
	84	facilities->throughput = p[1];
	85	*vc_fac_mask \|= X25_MASK_THROUGHPUT;
	86	break;
a64b7b93 SP	87	case X25_MARKER:
a64b7b93 SP	88	break;
1da177e4 LT	89	default:
	90	printk(KERN_DEBUG "X.25: unknown facility "
	91	"%02X, value %02X\n",
	92	p[0], p[1]);
	93	break;
	94	}
	95	p += 2;
	96	len -= 2;
	97	break;
	98	case X25_FAC_CLASS_B:
	99	switch (*p) {
	100	case X25_FAC_PACKET_SIZE:
	101	facilities->pacsize_in = p[1];
	102	facilities->pacsize_out = p[2];
	103	*vc_fac_mask \|= X25_MASK_PACKET_SIZE;
	104	break;
	105	case X25_FAC_WINDOW_SIZE:
	106	facilities->winsize_in = p[1];
	107	facilities->winsize_out = p[2];
	108	*vc_fac_mask \|= X25_MASK_WINDOW_SIZE;
	109	break;
	110	default:
	111	printk(KERN_DEBUG "X.25: unknown facility "
	112	"%02X, values %02X, %02X\n",
	113	p[0], p[1], p[2]);
	114	break;
	115	}
	116	p += 3;
	117	len -= 3;
	118	break;
	119	case X25_FAC_CLASS_C:
	120	printk(KERN_DEBUG "X.25: unknown facility %02X, "
	121	"values %02X, %02X, %02X\n",
	122	p[0], p[1], p[2], p[3]);
	123	p += 4;
	124	len -= 4;
	125	break;
	126	case X25_FAC_CLASS_D:
a64b7b93 SP	127	switch (*p) {
	128	case X25_FAC_CALLING_AE:
	129	if (p[1] > X25_MAX_DTE_FACIL_LEN)
	130	break;
	131	dte_facs->calling_len = p[2];
	132	memcpy(dte_facs->calling_ae, &p[3], p[1] - 1);
	133	*vc_fac_mask \|= X25_MASK_CALLING_AE;
	134	break;
	135	case X25_FAC_CALLED_AE:
	136	if (p[1] > X25_MAX_DTE_FACIL_LEN)
	137	break;
	138	dte_facs->called_len = p[2];
	139	memcpy(dte_facs->called_ae, &p[3], p[1] - 1);
	140	*vc_fac_mask \|= X25_MASK_CALLED_AE;
	141	break;
	142	default:
	143	printk(KERN_DEBUG "X.25: unknown facility %02X,"
	144	"length %d, values %02X, %02X, "
	145	"%02X, %02X\n",
	146	p[0], p[1], p[2], p[3], p[4], p[5]);
	147	break;
	148	}
1da177e4	149	len -= p[1] + 2;
a64b7b93	150	p += p[1] + 2;
1da177e4 LT	151	break;
	152	}
	153	}
	154
	155	return p - skb->data;
	156	}
	157
	158	/*
	159	* Create a set of facilities.
	160	*/
	161	int x25_create_facilities(unsigned char *buffer,
a64b7b93 SP	162	struct x25_facilities *facilities,
a64b7b93 SP	163	struct x25_dte_facilities *dte_facs, unsigned long facil_mask)
1da177e4 LT	164	{
	165	unsigned char *p = buffer + 1;
	166	int len;
	167
	168	if (!facil_mask) {
	169	/*
	170	* Length of the facilities field in call_req or
	171	* call_accept packets
	172	*/
	173	buffer[0] = 0;
	174	len = 1; /* 1 byte for the length field */
	175	return len;
	176	}
	177
	178	if (facilities->reverse && (facil_mask & X25_MASK_REVERSE)) {
	179	*p++ = X25_FAC_REVERSE;
ebc3f64b	180	*p++ = facilities->reverse;
1da177e4 LT	181	}
	182
	183	if (facilities->throughput && (facil_mask & X25_MASK_THROUGHPUT)) {
	184	*p++ = X25_FAC_THROUGHPUT;
	185	*p++ = facilities->throughput;
	186	}
	187
	188	if ((facilities->pacsize_in \|\| facilities->pacsize_out) &&
	189	(facil_mask & X25_MASK_PACKET_SIZE)) {
	190	*p++ = X25_FAC_PACKET_SIZE;
	191	*p++ = facilities->pacsize_in ? : facilities->pacsize_out;
	192	*p++ = facilities->pacsize_out ? : facilities->pacsize_in;
	193	}
	194
	195	if ((facilities->winsize_in \|\| facilities->winsize_out) &&
	196	(facil_mask & X25_MASK_WINDOW_SIZE)) {
	197	*p++ = X25_FAC_WINDOW_SIZE;
	198	*p++ = facilities->winsize_in ? : facilities->winsize_out;
	199	*p++ = facilities->winsize_out ? : facilities->winsize_in;
	200	}
	201
a64b7b93 SP	202	if (facil_mask & (X25_MASK_CALLING_AE\|X25_MASK_CALLED_AE)) {
	203	*p++ = X25_MARKER;
	204	*p++ = X25_DTE_SERVICES;
	205	}
	206
	207	if (dte_facs->calling_len && (facil_mask & X25_MASK_CALLING_AE)) {
	208	unsigned bytecount = (dte_facs->calling_len % 2) ?
	209	dte_facs->calling_len / 2 + 1 :
	210	dte_facs->calling_len / 2;
	211	*p++ = X25_FAC_CALLING_AE;
	212	*p++ = 1 + bytecount;
	213	*p++ = dte_facs->calling_len;
	214	memcpy(p, dte_facs->calling_ae, bytecount);
	215	p += bytecount;
	216	}
	217
	218	if (dte_facs->called_len && (facil_mask & X25_MASK_CALLED_AE)) {
	219	unsigned bytecount = (dte_facs->called_len % 2) ?
	220	dte_facs->called_len / 2 + 1 :
	221	dte_facs->called_len / 2;
	222	*p++ = X25_FAC_CALLED_AE;
	223	*p++ = 1 + bytecount;
	224	*p++ = dte_facs->called_len;
	225	memcpy(p, dte_facs->called_ae, bytecount);
	226	p+=bytecount;
	227	}
	228
1da177e4 LT	229	len = p - buffer;
	230	buffer[0] = len - 1;
	231
	232	return len;
	233	}
	234
	235	/*
	236	* Try to reach a compromise on a set of facilities.
	237	*
	238	* The only real problem is with reverse charging.
	239	*/
	240	int x25_negotiate_facilities(struct sk_buff skb, struct sock sk,
a64b7b93	241	struct x25_facilities new, struct x25_dte_facilities dte)
1da177e4 LT	242	{
	243	struct x25_sock *x25 = x25_sk(sk);
	244	struct x25_facilities *ours = &x25->facilities;
	245	struct x25_facilities theirs;
	246	int len;
	247
	248	memset(&theirs, 0, sizeof(theirs));
	249	memcpy(new, ours, sizeof(*new));
	250
a64b7b93	251	len = x25_parse_facilities(skb, &theirs, dte, &x25->vc_facil_mask);
1da177e4 LT	252
	253	/*
	254	* They want reverse charging, we won't accept it.
	255	*/
ebc3f64b	256	if ((theirs.reverse & 0x01 ) && (ours->reverse & 0x01)) {
1da177e4 LT	257	SOCK_DEBUG(sk, "X.25: rejecting reverse charging request");
	258	return -1;
	259	}
	260
	261	new->reverse = theirs.reverse;
	262
	263	if (theirs.throughput) {
	264	if (theirs.throughput < ours->throughput) {
	265	SOCK_DEBUG(sk, "X.25: throughput negotiated down");
	266	new->throughput = theirs.throughput;
	267	}
	268	}
	269
	270	if (theirs.pacsize_in && theirs.pacsize_out) {
	271	if (theirs.pacsize_in < ours->pacsize_in) {
	272	SOCK_DEBUG(sk, "X.25: packet size inwards negotiated down");
	273	new->pacsize_in = theirs.pacsize_in;
	274	}
	275	if (theirs.pacsize_out < ours->pacsize_out) {
	276	SOCK_DEBUG(sk, "X.25: packet size outwards negotiated down");
	277	new->pacsize_out = theirs.pacsize_out;
	278	}
	279	}
	280
	281	if (theirs.winsize_in && theirs.winsize_out) {
	282	if (theirs.winsize_in < ours->winsize_in) {
	283	SOCK_DEBUG(sk, "X.25: window size inwards negotiated down");
	284	new->winsize_in = theirs.winsize_in;
	285	}
	286	if (theirs.winsize_out < ours->winsize_out) {
	287	SOCK_DEBUG(sk, "X.25: window size outwards negotiated down");
	288	new->winsize_out = theirs.winsize_out;
	289	}
	290	}
	291
	292	return len;
	293	}
	294
	295	/*
	296	* Limit values of certain facilities according to the capability of the
	297	* currently attached x25 link.
	298	*/
	299	void x25_limit_facilities(struct x25_facilities *facilities,
	300	struct x25_neigh *nb)
	301	{
	302
	303	if (!nb->extended) {
	304	if (facilities->winsize_in > 7) {
	305	printk(KERN_DEBUG "X.25: incoming winsize limited to 7\n");
	306	facilities->winsize_in = 7;
	307	}
	308	if (facilities->winsize_out > 7) {
	309	facilities->winsize_out = 7;
	310	printk( KERN_DEBUG "X.25: outgoing winsize limited to 7\n");
	311	}
	312	}
	313	}