Revision 25fb6ca4ed9cad72f14f61629b68dc03c0d9713f authored by Balakumaran Kannan on 02 April 2013, 10:45:05 UTC, committed by David S. Miller on 02 April 2013, 18:37:19 UTC
IPv6 Routing table becomes broken once we do ifdown, ifup of the loopback(lo) interface. After down-up, routes of other interface's IPv6 addresses through 'lo' are lost. IPv6 addresses assigned to all interfaces are routed through 'lo' for internal communication. Once 'lo' is down, those routing entries are removed from routing table. But those removed entries are not being re-created properly when 'lo' is brought up. So IPv6 addresses of other interfaces becomes unreachable from the same machine. Also this breaks communication with other machines because of NDISC packet processing failure. This patch fixes this issue by reading all interface's IPv6 addresses and adding them to IPv6 routing table while bringing up 'lo'. ==Testing== Before applying the patch: $ route -A inet6 Kernel IPv6 routing table Destination Next Hop Flag Met Ref Use If 2000::20/128 :: U 256 0 0 eth0 fe80::/64 :: U 256 0 0 eth0 ::/0 :: !n -1 1 1 lo ::1/128 :: Un 0 1 0 lo 2000::20/128 :: Un 0 1 0 lo fe80::xxxx:xxxx:xxxx:xxxx/128 :: Un 0 1 0 lo ff00::/8 :: U 256 0 0 eth0 ::/0 :: !n -1 1 1 lo $ sudo ifdown lo $ sudo ifup lo $ route -A inet6 Kernel IPv6 routing table Destination Next Hop Flag Met Ref Use If 2000::20/128 :: U 256 0 0 eth0 fe80::/64 :: U 256 0 0 eth0 ::/0 :: !n -1 1 1 lo ::1/128 :: Un 0 1 0 lo ff00::/8 :: U 256 0 0 eth0 ::/0 :: !n -1 1 1 lo $ After applying the patch: $ route -A inet6 Kernel IPv6 routing table Destination Next Hop Flag Met Ref Use If 2000::20/128 :: U 256 0 0 eth0 fe80::/64 :: U 256 0 0 eth0 ::/0 :: !n -1 1 1 lo ::1/128 :: Un 0 1 0 lo 2000::20/128 :: Un 0 1 0 lo fe80::xxxx:xxxx:xxxx:xxxx/128 :: Un 0 1 0 lo ff00::/8 :: U 256 0 0 eth0 ::/0 :: !n -1 1 1 lo $ sudo ifdown lo $ sudo ifup lo $ route -A inet6 Kernel IPv6 routing table Destination Next Hop Flag Met Ref Use If 2000::20/128 :: U 256 0 0 eth0 fe80::/64 :: U 256 0 0 eth0 ::/0 :: !n -1 1 1 lo ::1/128 :: Un 0 1 0 lo 2000::20/128 :: Un 0 1 0 lo fe80::xxxx:xxxx:xxxx:xxxx/128 :: Un 0 1 0 lo ff00::/8 :: U 256 0 0 eth0 ::/0 :: !n -1 1 1 lo $ Signed-off-by: Balakumaran Kannan <Balakumaran.Kannan@ap.sony.com> Signed-off-by: Maruthi Thotad <Maruthi.Thotad@ap.sony.com> Signed-off-by: David S. Miller <davem@davemloft.net>
1 parent f0f6ee1
jiffies.c
/***********************************************************************
* linux/kernel/time/jiffies.c
*
* This file contains the jiffies based clocksource.
*
* Copyright (C) 2004, 2005 IBM, John Stultz (johnstul@us.ibm.com)
*
* 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.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*
************************************************************************/
#include <linux/clocksource.h>
#include <linux/jiffies.h>
#include <linux/module.h>
#include <linux/init.h>
#include "tick-internal.h"
/* The Jiffies based clocksource is the lowest common
* denominator clock source which should function on
* all systems. It has the same coarse resolution as
* the timer interrupt frequency HZ and it suffers
* inaccuracies caused by missed or lost timer
* interrupts and the inability for the timer
* interrupt hardware to accuratly tick at the
* requested HZ value. It is also not recommended
* for "tick-less" systems.
*/
#define NSEC_PER_JIFFY ((NSEC_PER_SEC+HZ/2)/HZ)
/* Since jiffies uses a simple NSEC_PER_JIFFY multiplier
* conversion, the .shift value could be zero. However
* this would make NTP adjustments impossible as they are
* in units of 1/2^.shift. Thus we use JIFFIES_SHIFT to
* shift both the nominator and denominator the same
* amount, and give ntp adjustments in units of 1/2^8
*
* The value 8 is somewhat carefully chosen, as anything
* larger can result in overflows. NSEC_PER_JIFFY grows as
* HZ shrinks, so values greater than 8 overflow 32bits when
* HZ=100.
*/
#define JIFFIES_SHIFT 8
static cycle_t jiffies_read(struct clocksource *cs)
{
return (cycle_t) jiffies;
}
static struct clocksource clocksource_jiffies = {
.name = "jiffies",
.rating = 1, /* lowest valid rating*/
.read = jiffies_read,
.mask = 0xffffffff, /*32bits*/
.mult = NSEC_PER_JIFFY << JIFFIES_SHIFT, /* details above */
.shift = JIFFIES_SHIFT,
};
__cacheline_aligned_in_smp DEFINE_SEQLOCK(jiffies_lock);
#if (BITS_PER_LONG < 64)
u64 get_jiffies_64(void)
{
unsigned long seq;
u64 ret;
do {
seq = read_seqbegin(&jiffies_lock);
ret = jiffies_64;
} while (read_seqretry(&jiffies_lock, seq));
return ret;
}
EXPORT_SYMBOL(get_jiffies_64);
#endif
EXPORT_SYMBOL(jiffies);
static int __init init_jiffies_clocksource(void)
{
return clocksource_register(&clocksource_jiffies);
}
core_initcall(init_jiffies_clocksource);
struct clocksource * __init __weak clocksource_default_clock(void)
{
return &clocksource_jiffies;
}
struct clocksource refined_jiffies;
int register_refined_jiffies(long cycles_per_second)
{
u64 nsec_per_tick, shift_hz;
long cycles_per_tick;
refined_jiffies = clocksource_jiffies;
refined_jiffies.name = "refined-jiffies";
refined_jiffies.rating++;
/* Calc cycles per tick */
cycles_per_tick = (cycles_per_second + HZ/2)/HZ;
/* shift_hz stores hz<<8 for extra accuracy */
shift_hz = (u64)cycles_per_second << 8;
shift_hz += cycles_per_tick/2;
do_div(shift_hz, cycles_per_tick);
/* Calculate nsec_per_tick using shift_hz */
nsec_per_tick = (u64)NSEC_PER_SEC << 8;
nsec_per_tick += (u32)shift_hz/2;
do_div(nsec_per_tick, (u32)shift_hz);
refined_jiffies.mult = ((u32)nsec_per_tick) << JIFFIES_SHIFT;
clocksource_register(&refined_jiffies);
return 0;
}
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