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-rw-r--r--net/x25/x25_facilities.c231
1 files changed, 231 insertions, 0 deletions
diff --git a/net/x25/x25_facilities.c b/net/x25/x25_facilities.c
new file mode 100644
index 0000000..a21bdb9
--- /dev/null
+++ b/net/x25/x25_facilities.c
@@ -0,0 +1,231 @@
+/*
+ * 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.
+ */
+
+#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 structure. Unrecognised
+ * facilities are written to the debug log file.
+ */
+int x25_parse_facilities(struct sk_buff *skb,
+ struct x25_facilities *facilities,
+ unsigned long *vc_fac_mask)
+{
+ unsigned char *p = skb->data;
+ unsigned int len = *p++;
+
+ *vc_fac_mask = 0;
+
+ while (len > 0) {
+ switch (*p & X25_FAC_CLASS_MASK) {
+ case X25_FAC_CLASS_A:
+ switch (*p) {
+ case X25_FAC_REVERSE:
+ facilities->reverse = p[1] & 0x01;
+ *vc_fac_mask |= X25_MASK_REVERSE;
+ break;
+ case X25_FAC_THROUGHPUT:
+ facilities->throughput = p[1];
+ *vc_fac_mask |= X25_MASK_THROUGHPUT;
+ 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:
+ 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]);
+ 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,
+ 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;
+ }
+
+ 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_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, &x25->vc_facil_mask);
+
+ /*
+ * They want reverse charging, we won't accept it.
+ */
+ if (theirs.reverse && ours->reverse) {
+ 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");
+ }
+ }
+}
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