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2 * tc_core.c TC core library.
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License
6 * as published by the Free Software Foundation; either version
7 * 2 of the License, or (at your option) any later version.
9 * Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
19 #include <sys/socket.h>
20 #include <netinet/in.h>
21 #include <arpa/inet.h>
26 #include <linux/atm.h>
28 static double tick_in_usec
= 1;
29 static double clock_factor
= 1;
31 int tc_core_time2big(unsigned int time
)
36 return (t
>> 32) != 0;
40 unsigned int tc_core_time2tick(unsigned int time
)
42 return time
*tick_in_usec
;
45 unsigned int tc_core_tick2time(unsigned int tick
)
47 return tick
/tick_in_usec
;
50 unsigned int tc_core_time2ktime(unsigned int time
)
52 return time
* clock_factor
;
55 unsigned int tc_core_ktime2time(unsigned int ktime
)
57 return ktime
/ clock_factor
;
60 unsigned int tc_calc_xmittime(__u64 rate
, unsigned int size
)
62 return tc_core_time2tick(TIME_UNITS_PER_SEC
*((double)size
/(double)rate
));
65 unsigned int tc_calc_xmitsize(__u64 rate
, unsigned int ticks
)
67 return ((double)rate
*tc_core_tick2time(ticks
))/TIME_UNITS_PER_SEC
;
71 * The align to ATM cells is used for determining the (ATM) SAR
72 * alignment overhead at the ATM layer. (SAR = Segmentation And
73 * Reassembly). This is for example needed when scheduling packet on
74 * an ADSL connection. Note that the extra ATM-AAL overhead is _not_
75 * included in this calculation. This overhead is added in the kernel
76 * before doing the rate table lookup, as this gives better precision
77 * (as the table will always be aligned for 48 bytes).
78 * --Hawk, d.7/11-2004. <hawk@diku.dk>
80 static unsigned int tc_align_to_atm(unsigned int size
)
84 cells
= size
/ ATM_CELL_PAYLOAD
;
85 if ((size
% ATM_CELL_PAYLOAD
) > 0)
88 linksize
= cells
* ATM_CELL_SIZE
; /* Use full cell size to add ATM tax */
92 static unsigned int tc_adjust_size(unsigned int sz
, unsigned int mpu
, enum link_layer linklayer
)
99 return tc_align_to_atm(sz
);
100 case LINKLAYER_ETHERNET
:
102 /* No size adjustments on Ethernet */
107 /* Notice, the rate table calculated here, have gotten replaced in the
108 * kernel and is no-longer used for lookups.
110 * This happened in kernel release v3.8 caused by kernel
111 * - commit 56b765b79 ("htb: improved accuracy at high rates").
112 * This change unfortunately caused breakage of tc overhead and
113 * linklayer parameters.
115 * Kernel overhead handling got fixed in kernel v3.10 by
116 * - commit 01cb71d2d47 (net_sched: restore "overhead xxx" handling)
118 * Kernel linklayer handling got fixed in kernel v3.11 by
119 * - commit 8a8e3d84b17 (net_sched: restore "linklayer atm" handling)
123 rtab[pkt_len>>cell_log] = pkt_xmit_time
126 int tc_calc_rtable(struct tc_ratespec
*r
, __u32
*rtab
,
127 int cell_log
, unsigned int mtu
,
128 enum link_layer linklayer
)
132 unsigned int bps
= r
->rate
;
133 unsigned int mpu
= r
->mpu
;
140 while ((mtu
>> cell_log
) > 255)
144 for (i
= 0; i
< 256; i
++) {
145 sz
= tc_adjust_size((i
+ 1) << cell_log
, mpu
, linklayer
);
146 rtab
[i
] = tc_calc_xmittime(bps
, sz
);
150 r
->cell_log
= cell_log
;
151 r
->linklayer
= (linklayer
& TC_LINKLAYER_MASK
);
156 stab[pkt_len>>cell_log] = pkt_xmit_size>>size_log
159 int tc_calc_size_table(struct tc_sizespec
*s
, __u16
**stab
)
162 enum link_layer linklayer
= s
->linklayer
;
165 if (linklayer
<= LINKLAYER_ETHERNET
&& s
->mpu
== 0) {
166 /* don't need data table in this case (only overhead set) */
181 while ((s
->mtu
>> s
->cell_log
) > s
->tsize
- 1)
184 *stab
= malloc(s
->tsize
* sizeof(__u16
));
189 for (i
= s
->tsize
- 1; i
>= 0; i
--) {
190 sz
= tc_adjust_size((i
+ 1) << s
->cell_log
, s
->mpu
, linklayer
);
191 if ((sz
>> s
->size_log
) > UINT16_MAX
) {
195 (*stab
)[i
] = sz
>> s
->size_log
;
198 s
->cell_align
= -1; /* Due to the sz calc */
202 int tc_core_init(void)
209 fp
= fopen("/proc/net/psched", "r");
213 if (fscanf(fp
, "%08x%08x%08x", &t2us
, &us2t
, &clock_res
) != 3) {
219 /* compatibility hack: for old iproute binaries (ignoring
220 * the kernel clock resolution) the kernel advertises a
221 * tick multiplier of 1000 in case of nano-second resolution,
222 * which really is 1. */
223 if (clock_res
== 1000000000)
226 clock_factor
= (double)clock_res
/ TIME_UNITS_PER_SEC
;
227 tick_in_usec
= (double)t2us
/ us2t
* clock_factor
;