1 files changed, 258 insertions, 0 deletions
diff --git a/tc/tc_core.c b/tc/tc_core.c
new file mode 100644
index 0000000..498d35d
--- /dev/null
+++ b/tc/tc_core.c
@@ -0,0 +1,258 @@
+/*
+ * tc_core.c		TC core library.
+ *
+ *		This program 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.
+ *
+ * Authors:	Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
+ *
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <math.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+#include <string.h>
+
+#include "utils.h"
+#include "tc_core.h"
+#include <linux/atm.h>
+
+static double tick_in_usec = 1;
+static double clock_factor = 1;
+
+int tc_core_time2big(unsigned int time)
+{
+	__u64 t = time;
+
+	t *= tick_in_usec;
+	return (t >> 32) != 0;
+}
+
+
+unsigned int tc_core_time2tick(unsigned int time)
+{
+	return time*tick_in_usec;
+}
+
+unsigned int tc_core_tick2time(unsigned int tick)
+{
+	return tick/tick_in_usec;
+}
+
+unsigned int tc_core_time2ktime(unsigned int time)
+{
+	return time * clock_factor;
+}
+
+unsigned int tc_core_ktime2time(unsigned int ktime)
+{
+	return ktime / clock_factor;
+}
+
+unsigned int tc_calc_xmittime(__u64 rate, unsigned int size)
+{
+	return tc_core_time2tick(TIME_UNITS_PER_SEC*((double)size/(double)rate));
+}
+
+unsigned int tc_calc_xmitsize(__u64 rate, unsigned int ticks)
+{
+	return ((double)rate*tc_core_tick2time(ticks))/TIME_UNITS_PER_SEC;
+}
+
+/*
+ * The align to ATM cells is used for determining the (ATM) SAR
+ * alignment overhead at the ATM layer. (SAR = Segmentation And
+ * Reassembly).  This is for example needed when scheduling packet on
+ * an ADSL connection.  Note that the extra ATM-AAL overhead is _not_
+ * included in this calculation. This overhead is added in the kernel
+ * before doing the rate table lookup, as this gives better precision
+ * (as the table will always be aligned for 48 bytes).
+ *  --Hawk, d.7/11-2004. <hawk@diku.dk>
+ */
+static unsigned int tc_align_to_atm(unsigned int size)
+{
+	int linksize, cells;
+
+	cells = size / ATM_CELL_PAYLOAD;
+	if ((size % ATM_CELL_PAYLOAD) > 0)
+		cells++;
+
+	linksize = cells * ATM_CELL_SIZE; /* Use full cell size to add ATM tax */
+	return linksize;
+}
+
+static unsigned int tc_adjust_size(unsigned int sz, unsigned int mpu, enum link_layer linklayer)
+{
+	if (sz < mpu)
+		sz = mpu;
+
+	switch (linklayer) {
+	case LINKLAYER_ATM:
+		return tc_align_to_atm(sz);
+	case LINKLAYER_ETHERNET:
+	default:
+		/* No size adjustments on Ethernet */
+		return sz;
+	}
+}
+
+/* Notice, the rate table calculated here, have gotten replaced in the
+ * kernel and is no-longer used for lookups.
+ *
+ * This happened in kernel release v3.8 caused by kernel
+ *  - commit 56b765b79 ("htb: improved accuracy at high rates").
+ * This change unfortunately caused breakage of tc overhead and
+ * linklayer parameters.
+ *
+ * Kernel overhead handling got fixed in kernel v3.10 by
+ * - commit 01cb71d2d47 (net_sched: restore "overhead xxx" handling)
+ *
+ * Kernel linklayer handling got fixed in kernel v3.11 by
+ * - commit 8a8e3d84b17 (net_sched: restore "linklayer atm" handling)
+ */
+
+/*
+   rtab[pkt_len>>cell_log] = pkt_xmit_time
+ */
+
+int tc_calc_rtable(struct tc_ratespec *r, __u32 *rtab,
+		   int cell_log, unsigned int mtu,
+		   enum link_layer linklayer)
+{
+	int i;
+	unsigned int sz;
+	unsigned int bps = r->rate;
+	unsigned int mpu = r->mpu;
+
+	if (mtu == 0)
+		mtu = 2047;
+
+	if (cell_log < 0) {
+		cell_log = 0;
+		while ((mtu >> cell_log) > 255)
+			cell_log++;
+	}
+
+	for (i = 0; i < 256; i++) {
+		sz = tc_adjust_size((i + 1) << cell_log, mpu, linklayer);
+		rtab[i] = tc_calc_xmittime(bps, sz);
+	}
+
+	r->cell_align =  -1;
+	r->cell_log = cell_log;
+	r->linklayer = (linklayer & TC_LINKLAYER_MASK);
+	return cell_log;
+}
+
+int tc_calc_rtable_64(struct tc_ratespec *r, __u32 *rtab,
+		   int cell_log, unsigned int mtu,
+		   enum link_layer linklayer, __u64 rate)
+{
+	int i;
+	unsigned int sz;
+	__u64 bps = rate;
+	unsigned int mpu = r->mpu;
+
+	if (mtu == 0)
+		mtu = 2047;
+
+	if (cell_log < 0) {
+		cell_log = 0;
+		while ((mtu >> cell_log) > 255)
+			cell_log++;
+	}
+
+	for (i = 0; i < 256; i++) {
+		sz = tc_adjust_size((i + 1) << cell_log, mpu, linklayer);
+		rtab[i] = tc_calc_xmittime(bps, sz);
+	}
+
+	r->cell_align =  -1;
+	r->cell_log = cell_log;
+	r->linklayer = (linklayer & TC_LINKLAYER_MASK);
+	return cell_log;
+}
+
+/*
+   stab[pkt_len>>cell_log] = pkt_xmit_size>>size_log
+ */
+
+int tc_calc_size_table(struct tc_sizespec *s, __u16 **stab)
+{
+	int i;
+	enum link_layer linklayer = s->linklayer;
+	unsigned int sz;
+
+	if (linklayer <= LINKLAYER_ETHERNET && s->mpu == 0) {
+		/* don't need data table in this case (only overhead set) */
+		s->mtu = 0;
+		s->tsize = 0;
+		s->cell_log = 0;
+		s->cell_align = 0;
+		*stab = NULL;
+		return 0;
+	}
+
+	if (s->mtu == 0)
+		s->mtu = 2047;
+	if (s->tsize == 0)
+		s->tsize = 512;
+
+	s->cell_log = 0;
+	while ((s->mtu >> s->cell_log) > s->tsize - 1)
+		s->cell_log++;
+
+	*stab = malloc(s->tsize * sizeof(__u16));
+	if (!*stab)
+		return -1;
+
+again:
+	for (i = s->tsize - 1; i >= 0; i--) {
+		sz = tc_adjust_size((i + 1) << s->cell_log, s->mpu, linklayer);
+		if ((sz >> s->size_log) > UINT16_MAX) {
+			s->size_log++;
+			goto again;
+		}
+		(*stab)[i] = sz >> s->size_log;
+	}
+
+	s->cell_align = -1; /* Due to the sz calc */
+	return 0;
+}
+
+int tc_core_init(void)
+{
+	FILE *fp;
+	__u32 clock_res;
+	__u32 t2us;
+	__u32 us2t;
+
+	fp = fopen("/proc/net/psched", "r");
+	if (fp == NULL)
+		return -1;
+
+	if (fscanf(fp, "%08x%08x%08x", &t2us, &us2t, &clock_res) != 3) {
+		fclose(fp);
+		return -1;
+	}
+	fclose(fp);
+
+	/* compatibility hack: for old iproute binaries (ignoring
+	 * the kernel clock resolution) the kernel advertises a
+	 * tick multiplier of 1000 in case of nano-second resolution,
+	 * which really is 1. */
+	if (clock_res == 1000000000)
+		t2us = us2t;
+
+	clock_factor  = (double)clock_res / TIME_UNITS_PER_SEC;
+	tick_in_usec = (double)t2us / us2t * clock_factor;
+	return 0;
+}