patch-2.3.15 linux/net/atm/atm_misc.c

• Lines: 124
• Date: Mon Aug 23 13:44:03 1999
• Orig file: v2.3.14/linux/net/atm/atm_misc.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.3.14/linux/net/atm/atm_misc.c linux/net/atm/atm_misc.c
@@ -0,0 +1,123 @@
+/* net/atm/atm_misc.c - Various functions for use by ATM drivers */
+
+/* Written 1995-1999 by Werner Almesberger, EPFL ICA */
+
+
+#include <linux/module.h>
+#include <linux/atm.h>
+#include <linux/atmdev.h>
+#include <linux/skbuff.h>
+#include <asm/atomic.h>
+#include <asm/errno.h>
+
+#include "tunable.h"
+
+
+int atm_charge(struct atm_vcc *vcc,int truesize)
+{
+	atm_force_charge(vcc,truesize);
+	if (atomic_read(&vcc->rx_inuse) <= vcc->rx_quota) return 1;
+	atm_return(vcc,truesize);
+	vcc->stats->rx_drop++;
+	return 0;
+}
+
+
+static int check_ci(struct atm_vcc *vcc,short vpi,int vci)
+{
+	struct atm_vcc *walk;
+
+	for (walk = vcc->dev->vccs; walk; walk = walk->next)
+		if ((walk->flags & ATM_VF_ADDR) && walk->vpi == vpi &&
+		    walk->vci == vci && ((walk->qos.txtp.traffic_class !=
+		    ATM_NONE && vcc->qos.txtp.traffic_class != ATM_NONE) ||
+		    (walk->qos.rxtp.traffic_class != ATM_NONE &&
+		    vcc->qos.rxtp.traffic_class != ATM_NONE)))
+			return -EADDRINUSE;
+		/* allow VCCs with same VPI/VCI iff they don't collide on
+		   TX/RX (but we may refuse such sharing for other reasons,
+		   e.g. if protocol requires to have both channels) */
+	return 0;
+}
+
+
+int atm_find_ci(struct atm_vcc *vcc,short *vpi,int *vci)
+{
+	static short p = 0; /* poor man's per-device cache */
+	static int c = 0;
+	short old_p;
+	int old_c;
+
+	if (*vpi != ATM_VPI_ANY && *vci != ATM_VCI_ANY)
+		return check_ci(vcc,*vpi,*vci);
+	/* last scan may have left values out of bounds for current device */
+	if (*vpi != ATM_VPI_ANY) p = *vpi;
+	else if (p >= 1 << vcc->dev->ci_range.vpi_bits) p = 0;
+	if (*vci != ATM_VCI_ANY) c = *vci;
+	else if (c < ATM_NOT_RSV_VCI || c >= 1 << vcc->dev->ci_range.vci_bits)
+			c = ATM_NOT_RSV_VCI;
+	old_p = p;
+	old_c = c;
+	do {
+		if (!check_ci(vcc,p,c)) {
+			*vpi = p;
+			*vci = c;
+			return 0;
+		}
+		if (*vci == ATM_VCI_ANY) {
+			c++;
+			if (c >= 1 << vcc->dev->ci_range.vci_bits)
+				c = ATM_NOT_RSV_VCI;
+		}
+		if ((c == ATM_NOT_RSV_VCI || *vci != ATM_VCI_ANY) &&
+		    *vpi == ATM_VPI_ANY) {
+			p++;
+			if (p >= 1 << vcc->dev->ci_range.vpi_bits) p = 0;
+		}
+	}
+	while (old_p != p || old_c != c);
+	return -EADDRINUSE;
+}
+
+
+/*
+ * atm_pcr_goal returns the positive PCR if it should be rounded up, the
+ * negative PCR if it should be rounded down, and zero if the maximum available
+ * bandwidth should be used.
+ *
+ * The rules are as follows (* = maximum, - = absent (0), x = value "x",
+ * (x+ = x or next value above x, x- = x or next value below):
+ *
+ *	min max pcr	result		min max pcr	result
+ *	-   -   -	* (UBR only)	x   -   -	x+
+ *	-   -   *	*		x   -   *	*
+ *	-   -   z	z-		x   -   z	z-
+ *	-   *   -	*		x   *   -	x+
+ *	-   *   *	*		x   *   *	*
+ *	-   *   z	z-		x   *   z	z-
+ *	-   y   -	y-		x   y   -	x+
+ *	-   y   *	y-		x   y   *	y-
+ *	-   y   z	z-		x   y   z	z-
+ *
+ * All non-error cases can be converted with the following simple set of rules:
+ *
+ *   if pcr == z then z-
+ *   else if min == x && pcr == - then x+
+ *     else if max == y then y-
+ *	 else *
+ */
+
+
+int atm_pcr_goal(struct atm_trafprm *tp)
+{
+	if (tp->pcr && tp->pcr != ATM_MAX_PCR) return -tp->pcr;
+	if (tp->min_pcr && !tp->pcr) return tp->min_pcr;
+	if (tp->max_pcr != ATM_MAX_PCR) return -tp->max_pcr;
+	return 0;
+}
+
+
+EXPORT_SYMBOL(atm_charge);
+EXPORT_SYMBOL(atm_return);
+EXPORT_SYMBOL(atm_find_ci);
+EXPORT_SYMBOL(atm_pcr_goal);