summaryrefslogtreecommitdiffstats
path: root/tc/tc_core.c
diff options
context:
space:
mode:
Diffstat (limited to 'tc/tc_core.c')
-rw-r--r--tc/tc_core.c253
1 files changed, 253 insertions, 0 deletions
diff --git a/tc/tc_core.c b/tc/tc_core.c
new file mode 100644
index 0000000..871ceb4
--- /dev/null
+++ b/tc/tc_core.c
@@ -0,0 +1,253 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * tc_core.c TC core library.
+ *
+ * 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;
+}