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Diffstat (limited to 'tc/tc_core.c')
-rw-r--r-- | tc/tc_core.c | 253 |
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; +} |