1 files changed, 355 insertions, 0 deletions

diff --git a/net/x25/x25_facilities.c b/net/x25/x25_facilities.c
new file mode 100644
index 000000000..ad1734d36
--- /dev/null
+++ b/net/x25/x25_facilities.c
@@ -0,0 +1,355 @@
+/*
+ *	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.
+ */
+
+#define pr_fmt(fmt) "X25: " fmt
+
+#include <linux/kernel.h>
+#include <linux/string.h>
+#include <linux/skbuff.h>
+#include <net/sock.h>
+#include <net/x25.h>
+
+/**
+ * x25_parse_facilities - Parse facilities from skb into the facilities structs
+ *
+ * @skb: sk_buff to parse
+ * @facilities: Regular facilities, updated as facilities are found
+ * @dte_facs: ITU DTE facilities, updated as DTE facilities are found
+ * @vc_fac_mask: mask is updated with all facilities found
+ *
+ * Return codes:
+ *  -1 - Parsing error, caller should drop call and clean up
+ *   0 - Parse OK, this skb has no facilities
+ *  >0 - Parse OK, returns the length of the facilities header
+ *
+ */
+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;
+	unsigned int len;
+
+	*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));
+
+	if (!pskb_may_pull(skb, 1))
+		return 0;
+
+	len = skb->data[0];
+
+	if (!pskb_may_pull(skb, 1 + len))
+		return -1;
+
+	p = skb->data + 1;
+
+	while (len > 0) {
+		switch (*p & X25_FAC_CLASS_MASK) {
+		case X25_FAC_CLASS_A:
+			if (len < 2)
+				return -1;
+			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;
+				}
+				/*fall through */
+			case X25_FAC_THROUGHPUT:
+				facilities->throughput = p[1];
+				*vc_fac_mask |= X25_MASK_THROUGHPUT;
+				break;
+			case X25_MARKER:
+				break;
+			default:
+				pr_debug("unknown facility "
+				       "%02X, value %02X\n",
+				       p[0], p[1]);
+				break;
+			}
+			p   += 2;
+			len -= 2;
+			break;
+		case X25_FAC_CLASS_B:
+			if (len < 3)
+				return -1;
+			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:
+				pr_debug("unknown facility "
+				       "%02X, values %02X, %02X\n",
+				       p[0], p[1], p[2]);
+				break;
+			}
+			p   += 3;
+			len -= 3;
+			break;
+		case X25_FAC_CLASS_C:
+			if (len < 4)
+				return -1;
+			pr_debug("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:
+			if (len < p[1] + 2)
+				return -1;
+			switch (*p) {
+			case X25_FAC_CALLING_AE:
+				if (p[1] > X25_MAX_DTE_FACIL_LEN || p[1] <= 1)
+					return -1;
+				if (p[2] > X25_MAX_AE_LEN)
+					return -1;
+				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 || p[1] <= 1)
+					return -1;
+				if (p[2] > X25_MAX_AE_LEN)
+					return -1;
+				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:
+				pr_debug("unknown facility %02X,"
+					"length %d\n", p[0], p[1]);
+				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 int bytecount = (dte_facs->calling_len + 1) >> 1;
+		*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 int 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));
+	memset(dte, 0, sizeof(*dte));
+
+	len = x25_parse_facilities(skb, &theirs, dte, &x25->vc_facil_mask);
+	if (len < 0)
+		return len;
+
+	/*
+	 *	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\n");
+		return -1;
+	}
+
+	new->reverse = theirs.reverse;
+
+	if (theirs.throughput) {
+		int theirs_in =  theirs.throughput & 0x0f;
+		int theirs_out = theirs.throughput & 0xf0;
+		int ours_in  = ours->throughput & 0x0f;
+		int ours_out = ours->throughput & 0xf0;
+		if (!ours_in || theirs_in < ours_in) {
+			SOCK_DEBUG(sk, "X.25: inbound throughput negotiated\n");
+			new->throughput = (new->throughput & 0xf0) | theirs_in;
+		}
+		if (!ours_out || theirs_out < ours_out) {
+			SOCK_DEBUG(sk,
+				"X.25: outbound throughput negotiated\n");
+			new->throughput = (new->throughput & 0x0f) | theirs_out;
+		}
+	}
+
+	if (theirs.pacsize_in && theirs.pacsize_out) {
+		if (theirs.pacsize_in < ours->pacsize_in) {
+			SOCK_DEBUG(sk, "X.25: packet size inwards negotiated down\n");
+			new->pacsize_in = theirs.pacsize_in;
+		}
+		if (theirs.pacsize_out < ours->pacsize_out) {
+			SOCK_DEBUG(sk, "X.25: packet size outwards negotiated down\n");
+			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\n");
+			new->winsize_in = theirs.winsize_in;
+		}
+		if (theirs.winsize_out < ours->winsize_out) {
+			SOCK_DEBUG(sk, "X.25: window size outwards negotiated down\n");
+			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) {
+			pr_debug("incoming winsize limited to 7\n");
+			facilities->winsize_in = 7;
+		}
+		if (facilities->winsize_out > 7) {
+			facilities->winsize_out = 7;
+			pr_debug("outgoing winsize limited to 7\n");
+		}
+	}
+}