[PATCH v3] fix the corner case of static route

[Baoquan He]

Previously for fixing the static route problem, all routes get through
a specific network interface will be saved and added in 2nd kernel.
Search pattern is used to get routes:
/sbin/ip route show | grep -v default | grep "^[[:digit:]].*via.* $_netdev"

An exception existed though, that is 2 machines connected directly and the
network interfaces wihch are configured as in different network subnets.

So in the v1 and v2, "ip route get to $target" command is executed and an
exact route to a target is saved and added in 2nd kernel. This works for
static route issue and can fix the corner case above.

v1:
    Introduced the new way which get exact route to remote target.

v1->v2:
    Since a grammer error which saved exact route, v2 is posted.

v2->v3:
    Per Vivek's comment, route to target should not be related to
    static ip issues. So in v3 introduced the get_routes function
    and take it out of kdump_static_ip.

Baoquan He (1):
  save exact route to remote target

dracut-module-setup.sh | 31 +++++++++++++++++++++++--------
 1 file changed, 23 insertions(+), 8 deletions(-)

[PATCH v3] save exact route to remote target

[Baoquan He]

Previously for solving static route issues, all routes which go
through a specific dev will be saved in 1st kernel, and then added
in 2nd kernel. Because we use below search pattern, an exception
will happen:
/sbin/ip route show | grep -v default | grep "^[[:digit:]].*via.* $_netdev"

That exception is a corner case which happened when 2 machines connected
directly by cable and the 2 network interfaces are configured in
different network subnets. E.g there are 2 machines A and B:

A:ens10 < ------ > B:ens9

A:ens10  inet 192.168.100.111/24 scope global ens10
route need be added in A:
192.168.110.0/24 dev ens10

B:ens9   inet 192.168.110.222/24 scope global ens9
route need be added in B
192.168.100.0/24 dev ens9

Now if A want to dump to B, the route "192.168.110.0/24 dev ens10"
has to be saved and added in 2nd kernel.

So in this patch "ip route get to $target" command is executed, then
an exact route can be got for going to that target. By this, static
route works and the corner case can be fixed too.

Signed-off-by: Baoquan He 
---
 dracut-module-setup.sh | 31 +++++++++++++++++++++++--------
 1 file changed, 23 insertions(+), 8 deletions(-)

diff --git a/dracut-module-setup.sh b/dracut-module-setup.sh
index 02a0557..9da1a41 100755
--- a/dracut-module-setup.sh
+++ b/dracut-module-setup.sh
@@ -79,11 +79,6 @@ kdump_static_ip() {
        _gateway=$(ip route list dev $_netdev | awk '/^default /{print $3}')
        echo -n "${_srcaddr}::${_gateway}:${_netmask}::"
     fi
-
-    /sbin/ip route show | grep -v default | grep "^[[:digit:]].*via.* $_netdev " |\
-    while read line; do
-        echo $line | awk '{printf("rd.route=%s:%s:%s\n", $1, $3, $5)}'
-    done >> ${initdir}/etc/cmdline.d/45route-static.conf
 }

kdump_get_mac_addr() {
@@ -212,9 +207,27 @@ kdump_setup_znet() {
     echo rd.znet=${NETTYPE},${SUBCHANNELS}${_options} > ${initdir}/etc/cmdline.d/30znet.conf
 }

+get_routes() {
+    local _netdev="$1" _target="$2"
+    local _route
+
+    _route=`/sbin/ip route get to $_target 2>&1`
+    if /sbin/ip route get to $_target | grep "via";
+    then
+        # route going to a different subnet via a router
+        echo $_route | awk '{printf("rd.route=%s:%s:%s\n", $1, $3, $5)}' \
+            >> ${initdir}/etc/cmdline.d/45route-static.conf
+    else
+        # route going to a different subnet though directly connected
+        echo $_route | awk '{printf("rd.route=%s::%s\n", $1, $3)}' \
+            >> ${initdir}/etc/cmdline.d/45route-static.conf
+    fi
+
+}
+
 # Setup dracut to bringup a given network interface
 kdump_setup_netdev() {
-    local _netdev=$1 _srcaddr=$2
+    local _netdev=$1 _srcaddr=$2 _target=$3
     local _static _proto _ip_conf _ip_opts _ifname_opts

if [ "$(uname -m)" = "s390x" ]; then
@@ -229,6 +242,8 @@ kdump_setup_netdev() {
         _proto=dhcp
     fi

+    get_routes $_netdev $_target
+
     _ip_conf="${initdir}/etc/cmdline.d/40ip.conf"
     _ip_opts=" ip=${_static}$(kdump_setup_ifname $_netdev):${_proto}"

@@ -281,7 +296,7 @@ kdump_install_net() {
         _netdev=`echo $_netdev|awk '{print $3}'|head -n 1`
     fi

-    kdump_setup_netdev "${_netdev}" "${_srcaddr}"
+    kdump_setup_netdev "${_netdev}" "${_srcaddr}" "${_server}"

#save netdev used for kdump as cmdline
     # Whoever calling kdump_install_net() is setting up the default gateway,
@@ -439,7 +454,7 @@ kdump_setup_iscsi_device() {
     srcaddr=$(echo $netdev | awk '{ print $3; exit }')
     netdev=$(echo $netdev | awk '{ print $1; exit }')

-    kdump_setup_netdev $netdev $srcaddr
+    kdump_setup_netdev $netdev $srcaddr $tgt_ipaddr

# prepare netroot= command line
     # FIXME: IPV6 addresses require explicit [] around $tgt_ipaddr

[PATCH v3] save exact route to remote target

[Baoquan He]

Hi,

This is the patch1/1. Please review this one. I will check that patch
series and add the patch sequence number if it doesn't have one in patch
subject.

Sorry if this makes you confused.

Thanks
Baoquan

On 08/18/14 at 04:34pm, Baoquan He wrote:
> Previously for solving static route issues, all routes which go
> through a specific dev will be saved in 1st kernel, and then added
> in 2nd kernel. Because we use below search pattern, an exception
> will happen:
> /sbin/ip route show | grep -v default | grep "^[[:digit:]].*via.* $_netdev"
>
> That exception is a corner case which happened when 2 machines connected
> directly by cable and the 2 network interfaces are configured in
> different network subnets. E.g there are 2 machines A and B:
>
> A:ens10 < ------ > B:ens9
>
> A:ens10  inet 192.168.100.111/24 scope global ens10
> route need be added in A:
> 192.168.110.0/24 dev ens10
>
> B:ens9   inet 192.168.110.222/24 scope global ens9
> route need be added in B
> 192.168.100.0/24 dev ens9
>
> Now if A want to dump to B, the route "192.168.110.0/24 dev ens10"
> has to be saved and added in 2nd kernel.
>
> So in this patch "ip route get to $target" command is executed, then
> an exact route can be got for going to that target. By this, static
> route works and the corner case can be fixed too.
> Signed-off-by: Baoquan He
>
> dracut-module-setup.sh | 31 +++++++++++++++++++++++--------
>  1 file changed, 23 insertions(+), 8 deletions(-)
>
> diff --git a/dracut-module-setup.sh b/dracut-module-setup.sh
> index 02a0557..9da1a41 100755
> --- a/dracut-module-setup.sh
> +++ b/dracut-module-setup.sh
> @@ -79,11 +79,6 @@ kdump_static_ip() {
>         _gateway=$(ip route list dev $_netdev | awk '/^default /{print $3}')
>         echo -n "${_srcaddr}::${_gateway}:${_netmask}::"
>      fi
> /sbin/ip route show | grep -v default | grep "^[[:digit:]].*via.* $_netdev " |\
> while read line; do
>    echo $line | awk '{printf("rd.route=%s:%s:%s\n", $1, $3, $5)}'
> done >> ${initdir}/etc/cmdline.d/45route-static.conf
>
> }
>
> kdump_get_mac_addr() {
> @@ -212,9 +207,27 @@ kdump_setup_znet() {
>      echo rd.znet=${NETTYPE},${SUBCHANNELS}${_options} > ${initdir}/etc/cmdline.d/30znet.conf
>  }
>
> +get_routes() {
> local _netdev="$1" _target="$2"
> local _route
> _route=`/sbin/ip route get to $_target 2>&1`
> if /sbin/ip route get to $_target | grep "via";
> then
>    # route going to a different subnet via a router
>    echo $_route | awk '{printf("rd.route=%s:%s:%s\n", $1, $3, $5)}' \
>        >> ${initdir}/etc/cmdline.d/45route-static.conf
> else
>    # route going to a different subnet though directly connected
>    echo $_route | awk '{printf("rd.route=%s::%s\n", $1, $3)}' \
>        >> ${initdir}/etc/cmdline.d/45route-static.conf
> fi
>
> +}
>
> # Setup dracut to bringup a given network interface
>  kdump_setup_netdev() {
> local _netdev=$1 _srcaddr=$2
>
> local _netdev=$1 _srcaddr=$2 _target=$3
> local _static _proto _ip_conf _ip_opts _ifname_opts
>
> if [ "$(uname -m)" = "s390x" ]; then
>
> @@ -229,6 +242,8 @@ kdump_setup_netdev() {
>          _proto=dhcp
>      fi
> get_routes $_netdev $_target
> _ip_conf="${initdir}/etc/cmdline.d/40ip.conf"
>    _ip_opts=" ip=${_static}$(kdump_setup_ifname $_netdev):${_proto}"
>
> @@ -281,7 +296,7 @@ kdump_install_net() {
>          _netdev=`echo $_netdev|awk '{print $3}'|head -n 1`
>      fi
> kdump_setup_netdev "${_netdev}" "${_srcaddr}"
>
> kdump_setup_netdev "${_netdev}" "${_srcaddr}" "${_server}"
>
> #save netdev used for kdump as cmdline
> # Whoever calling kdump_install_net() is setting up the default gateway,
>
> @@ -439,7 +454,7 @@ kdump_setup_iscsi_device() {
>      srcaddr=$(echo $netdev | awk '{ print $3; exit }')
>      netdev=$(echo $netdev | awk '{ print $1; exit }')
> kdump_setup_netdev $netdev $srcaddr
>
> kdump_setup_netdev $netdev $srcaddr $tgt_ipaddr
>
> # prepare netroot= command line
> # FIXME: IPV6 addresses require explicit [] around $tgt_ipaddr
>
> -- 
> 1.9.0

[PATCH v3] save exact route to remote target

[Vivek Goyal]

On Tue, Aug 19, 2014 at 10:24:16AM +0800, Baoquan He wrote:
> Hi,
>
> This is the patch1/1. Please review this one. I will check that patch
> series and add the patch sequence number if it doesn't have one in patch
> subject.

Hi Bao,

git-send-email automatically creates a series and adds these numbers.

I use following.

git send-email --no-chain-reply-to --no-signed-off-by-cc --suppress-from
--suppress-cc all --to <recepient-mail-id>  patches-sent/

Thanks
Vivek
> Sorry if this makes you confused.
>
> Thanks
> Baoquan
>
> On 08/18/14 at 04:34pm, Baoquan He wrote:
> > Previously for solving static route issues, all routes which go
> > through a specific dev will be saved in 1st kernel, and then added
> > in 2nd kernel. Because we use below search pattern, an exception
> > will happen:
> > /sbin/ip route show | grep -v default | grep "^[[:digit:]].*via.* $_netdev"
> >
> > That exception is a corner case which happened when 2 machines connected
> > directly by cable and the 2 network interfaces are configured in
> > different network subnets. E.g there are 2 machines A and B:
> >
> > A:ens10 < ------ > B:ens9
> >
> > A:ens10  inet 192.168.100.111/24 scope global ens10
> > route need be added in A:
> > 192.168.110.0/24 dev ens10
> >
> > B:ens9   inet 192.168.110.222/24 scope global ens9
> > route need be added in B
> > 192.168.100.0/24 dev ens9
> >
> > Now if A want to dump to B, the route "192.168.110.0/24 dev ens10"
> > has to be saved and added in 2nd kernel.
> >
> > So in this patch "ip route get to $target" command is executed, then
> > an exact route can be got for going to that target. By this, static
> > route works and the corner case can be fixed too.
> > Signed-off-by: Baoquan He
> >
> > dracut-module-setup.sh | 31 +++++++++++++++++++++++--------
> >  1 file changed, 23 insertions(+), 8 deletions(-)
> >
> > diff --git a/dracut-module-setup.sh b/dracut-module-setup.sh
> > index 02a0557..9da1a41 100755
> > --- a/dracut-module-setup.sh
> > +++ b/dracut-module-setup.sh
> > @@ -79,11 +79,6 @@ kdump_static_ip() {
> >         _gateway=$(ip route list dev $_netdev | awk '/^default /{print $3}')
> >         echo -n "${_srcaddr}::${_gateway}:${_netmask}::"
> >      fi
> > /sbin/ip route show | grep -v default | grep "^[[:digit:]].*via.* $_netdev " |\
> > while read line; do
> >    echo $line | awk '{printf("rd.route=%s:%s:%s\n", $1, $3, $5)}'
> > done >> ${initdir}/etc/cmdline.d/45route-static.conf
> >
> > }
> >
> > kdump_get_mac_addr() {
> > @@ -212,9 +207,27 @@ kdump_setup_znet() {
> >      echo rd.znet=${NETTYPE},${SUBCHANNELS}${_options} > ${initdir}/etc/cmdline.d/30znet.conf
> >  }
> >
> > +get_routes() {
> > local _netdev="$1" _target="$2"
> > local _route
> > _route=`/sbin/ip route get to $_target 2>&1`
> > if /sbin/ip route get to $_target | grep "via";
> > then
> >    # route going to a different subnet via a router
> >    echo $_route | awk '{printf("rd.route=%s:%s:%s\n", $1, $3, $5)}' \
> >        >> ${initdir}/etc/cmdline.d/45route-static.conf
> > else
> >    # route going to a different subnet though directly connected
> >    echo $_route | awk '{printf("rd.route=%s::%s\n", $1, $3)}' \
> >        >> ${initdir}/etc/cmdline.d/45route-static.conf
> > fi
> >
> > +}
> >
> > # Setup dracut to bringup a given network interface
> >  kdump_setup_netdev() {
> > local _netdev=$1 _srcaddr=$2
> >
> > local _netdev=$1 _srcaddr=$2 _target=$3
> > local _static _proto _ip_conf _ip_opts _ifname_opts
> >
> > if [ "$(uname -m)" = "s390x" ]; then
> >
> > @@ -229,6 +242,8 @@ kdump_setup_netdev() {
> >          _proto=dhcp
> >      fi
> > get_routes $_netdev $_target
> > _ip_conf="${initdir}/etc/cmdline.d/40ip.conf"
> >    _ip_opts=" ip=${_static}$(kdump_setup_ifname $_netdev):${_proto}"
> >
> > @@ -281,7 +296,7 @@ kdump_install_net() {
> >          _netdev=`echo $_netdev|awk '{print $3}'|head -n 1`
> >      fi
> > kdump_setup_netdev "${_netdev}" "${_srcaddr}"
> >
> > kdump_setup_netdev "${_netdev}" "${_srcaddr}" "${_server}"
> >
> > #save netdev used for kdump as cmdline
> > # Whoever calling kdump_install_net() is setting up the default gateway,
> >
> > @@ -439,7 +454,7 @@ kdump_setup_iscsi_device() {
> >      srcaddr=$(echo $netdev | awk '{ print $3; exit }')
> >      netdev=$(echo $netdev | awk '{ print $1; exit }')
> > kdump_setup_netdev $netdev $srcaddr
> >
> > kdump_setup_netdev $netdev $srcaddr $tgt_ipaddr
> >
> > # prepare netroot= command line
> > # FIXME: IPV6 addresses require explicit [] around $tgt_ipaddr
> >
> > -- 
> > 1.9.0
>
> kexec mailing list
> [e-mail]
> https://lists.fedoraproject.org/mailman/listinfo/kexec

[PATCH v3] save exact route to remote target

[Vivek Goyal]

On Mon, Aug 18, 2014 at 04:34:53PM +0800, Baoquan He wrote:
> Previously for solving static route issues, all routes which go
> through a specific dev will be saved in 1st kernel, and then added
> in 2nd kernel. Because we use below search pattern, an exception
> will happen:
> /sbin/ip route show | grep -v default | grep "^[[:digit:]].*via.* $_netdev"
>
> That exception is a corner case which happened when 2 machines connected
> directly by cable and the 2 network interfaces are configured in
> different network subnets. E.g there are 2 machines A and B:
>
> A:ens10 < ------ > B:ens9
>
> A:ens10  inet 192.168.100.111/24 scope global ens10
> route need be added in A:
> 192.168.110.0/24 dev ens10
>
> B:ens9   inet 192.168.110.222/24 scope global ens9
> route need be added in B
> 192.168.100.0/24 dev ens9
>
> Now if A want to dump to B, the route "192.168.110.0/24 dev ens10"
> has to be saved and added in 2nd kernel.
>
> So in this patch "ip route get to $target" command is executed, then
> an exact route can be got for going to that target. By this, static
> route works and the corner case can be fixed too.

Hi Bao,

Using "ip route get to" requires knowing the target. But that's little
different than bringing up an interface. There can be multiple static
routes going through an interface which lead to multiple targets.

I think this makes the whole mechanism less generic. I liked the previous
method better where if we bring an interface, all the static routes going
through that interface will come up too. (Instead of only one static
route coming up for the target).

So I would rather stick to the mechanism of determining all the routes
going through an interface and add the ones which are not present in
second kernel's routing table.

Thanks
Vivek
> Signed-off-by: Baoquan He
>
> dracut-module-setup.sh | 31 +++++++++++++++++++++++--------
>  1 file changed, 23 insertions(+), 8 deletions(-)
>
> diff --git a/dracut-module-setup.sh b/dracut-module-setup.sh
> index 02a0557..9da1a41 100755
> --- a/dracut-module-setup.sh
> +++ b/dracut-module-setup.sh
> @@ -79,11 +79,6 @@ kdump_static_ip() {
>         _gateway=$(ip route list dev $_netdev | awk '/^default /{print $3}')
>         echo -n "${_srcaddr}::${_gateway}:${_netmask}::"
>      fi
> /sbin/ip route show | grep -v default | grep "^[[:digit:]].*via.* $_netdev " |\
> while read line; do
>    echo $line | awk '{printf("rd.route=%s:%s:%s\n", $1, $3, $5)}'
> done >> ${initdir}/etc/cmdline.d/45route-static.conf
>
> }
>
> kdump_get_mac_addr() {
> @@ -212,9 +207,27 @@ kdump_setup_znet() {
>      echo rd.znet=${NETTYPE},${SUBCHANNELS}${_options} > ${initdir}/etc/cmdline.d/30znet.conf
>  }
>
> +get_routes() {
> local _netdev="$1" _target="$2"
> local _route
> _route=`/sbin/ip route get to $_target 2>&1`
> if /sbin/ip route get to $_target | grep "via";
> then
>    # route going to a different subnet via a router
>    echo $_route | awk '{printf("rd.route=%s:%s:%s\n", $1, $3, $5)}' \
>        >> ${initdir}/etc/cmdline.d/45route-static.conf
> else
>    # route going to a different subnet though directly connected
>    echo $_route | awk '{printf("rd.route=%s::%s\n", $1, $3)}' \
>        >> ${initdir}/etc/cmdline.d/45route-static.conf
> fi
>
> +}
>
> # Setup dracut to bringup a given network interface
>  kdump_setup_netdev() {
> local _netdev=$1 _srcaddr=$2
>
> local _netdev=$1 _srcaddr=$2 _target=$3
> local _static _proto _ip_conf _ip_opts _ifname_opts
>
> if [ "$(uname -m)" = "s390x" ]; then
>
> @@ -229,6 +242,8 @@ kdump_setup_netdev() {
>          _proto=dhcp
>      fi
> get_routes $_netdev $_target
> _ip_conf="${initdir}/etc/cmdline.d/40ip.conf"
>    _ip_opts=" ip=${_static}$(kdump_setup_ifname $_netdev):${_proto}"
>
> @@ -281,7 +296,7 @@ kdump_install_net() {
>          _netdev=`echo $_netdev|awk '{print $3}'|head -n 1`
>      fi
> kdump_setup_netdev "${_netdev}" "${_srcaddr}"
>
> kdump_setup_netdev "${_netdev}" "${_srcaddr}" "${_server}"
>
> #save netdev used for kdump as cmdline
> # Whoever calling kdump_install_net() is setting up the default gateway,
>
> @@ -439,7 +454,7 @@ kdump_setup_iscsi_device() {
>      srcaddr=$(echo $netdev | awk '{ print $3; exit }')
>      netdev=$(echo $netdev | awk '{ print $1; exit }')
> kdump_setup_netdev $netdev $srcaddr
>
> kdump_setup_netdev $netdev $srcaddr $tgt_ipaddr
>
> # prepare netroot= command line
> # FIXME: IPV6 addresses require explicit [] around $tgt_ipaddr
>
> -- 
> 1.9.0
>
> kexec mailing list
> [e-mail]
> https://lists.fedoraproject.org/mailman/listinfo/kexec

[PATCH v3] save exact route to remote target

[Vivek Goyal]

On Wed, Aug 20, 2014 at 10:42:28AM -0400, Vivek Goyal wrote:

[..]
> So I would rather stick to the mechanism of determining all the routes
> going through an interface and add the ones which are not present in
> second kernel's routing table.

Hi Bao,

In first kernel, who brings up the static routes? I am assuming Network
Manager. If that's the case, why not copy the relevant configuration
files in kdump initramfs and let network manager do the job.

Do we have network manager working in kdump initramfs or not?

Thanks
Vivek

[PATCH v3] save exact route to remote target

[Baoquan He]

On 08/20/14 at 01:47pm, Vivek Goyal wrote:
> On Wed, Aug 20, 2014 at 10:42:28AM -0400, Vivek Goyal wrote:
>
> [..]
> > So I would rather stick to the mechanism of determining all the routes
> > going through an interface and add the ones which are not present in
> > second kernel's routing table.
>
> Hi Bao,
>
> In first kernel, who brings up the static routes? I am assuming Network
> Manager. If that's the case, why not copy the relevant configuration
> files in kdump initramfs and let network manager do the job.

Yeah, originally I thought so. Later it's not about the static route.
Any route need be considered. It will be much simpler if only think
about the static route conf.

That will be /etc/sysconfig/route-eth0 according its using in 1st
kernel.
> Do we have network manager working in kdump initramfs or not?
>
> Thanks
> Vivek

[PATCH v3] save exact route to remote target

[Baoquan He]

On 08/20/14 at 10:42am, Vivek Goyal wrote:
> On Mon, Aug 18, 2014 at 04:34:53PM +0800, Baoquan He wrote:
> > Previously for solving static route issues, all routes which go
> > through a specific dev will be saved in 1st kernel, and then added
> > in 2nd kernel. Because we use below search pattern, an exception
> > will happen:
> > /sbin/ip route show | grep -v default | grep "^[[:digit:]].*via.* $_netdev"
> >
> > That exception is a corner case which happened when 2 machines connected
> > directly by cable and the 2 network interfaces are configured in
> > different network subnets. E.g there are 2 machines A and B:
> >
> > A:ens10 < ------ > B:ens9
> >
> > A:ens10  inet 192.168.100.111/24 scope global ens10
> > route need be added in A:
> > 192.168.110.0/24 dev ens10
> >
> > B:ens9   inet 192.168.110.222/24 scope global ens9
> > route need be added in B
> > 192.168.100.0/24 dev ens9
> >
> > Now if A want to dump to B, the route "192.168.110.0/24 dev ens10"
> > has to be saved and added in 2nd kernel.
> >
> > So in this patch "ip route get to $target" command is executed, then
> > an exact route can be got for going to that target. By this, static
> > route works and the corner case can be fixed too.
>
> Hi Bao,
>
> Using "ip route get to" requires knowing the target. But that's little
> different than bringing up an interface. There can be multiple static
> routes going through an interface which lead to multiple targets.
>
> I think this makes the whole mechanism less generic. I liked the previous
> method better where if we bring an interface, all the static routes going
> through that interface will come up too. (Instead of only one static
> route coming up for the target).
>
> So I would rather stick to the mechanism of determining all the routes
> going through an interface and add the ones which are not present in
> second kernel's routing table.

In fact, this issue has got out of the range of static route. In
previous implementation, all routes in 1st kernel which go through that
interface will be added to 2nd kernel. Among these routes, any routes
could be added, not only the static routes. Those manually added will be
added to 2nd kernel as long as it's an available route to target.

So now, could that be true that 2 targets are goint through 1 NIC, then
kdump_setup_netdev() will be called twice or 3 times?
> Thanks
> Vivek

[PATCH v3] save exact route to remote target

[Baoquan He]

On 08/20/14 at 10:42am, Vivek Goyal wrote:
> Hi Bao,
>
> Using "ip route get to" requires knowing the target. But that's little
> different than bringing up an interface. There can be multiple static
> routes going through an interface which lead to multiple targets.
>
> I think this makes the whole mechanism less generic. I liked the previous
> method better where if we bring an interface, all the static routes going
> through that interface will come up too. (Instead of only one static
> route coming up for the target).
>
> So I would rather stick to the mechanism of determining all the routes
> going through an interface and add the ones which are not present in
> second kernel's routing table.

I think you are right about this. Since Marc said other modules could
use network too, such as heartbeat. In kdump we need build the network
conf for it. I don't remember this clearly, need wait for Marc to check
this.

The reason I tried the exact route is some duplicate routes may exist in
dracut. From dracut's point of view, it can handle route correctly if
user can pass it the correct route. If duplicate routes are added,
either we tolerate the warning message, or we require to change the
implementation of dracut handling. But from dracut's side, they don't do
anything wrong, why they need be changed.
> Thanks
> Vivek

[PATCH v3] save exact route to remote target

[Marc Milgram]

Hi,

Sorry for the late response.

On 08/21/2014 08:34 AM, Baoquan He wrote:
> On 08/20/14 at 10:42am, Vivek Goyal wrote:
> > Hi Bao,
> >
> > Using "ip route get to" requires knowing the target. But that's little
> > different than bringing up an interface. There can be multiple static
> > routes going through an interface which lead to multiple targets.
> >
> > I think this makes the whole mechanism less generic. I liked the previous
> > method better where if we bring an interface, all the static routes going
> > through that interface will come up too. (Instead of only one static
> > route coming up for the target).
> >
> > So I would rather stick to the mechanism of determining all the routes
> > going through an interface and add the ones which are not present in
> > second kernel's routing table.
>
> I think you are right about this. Since Marc said other modules could
> use network too, such as heartbeat. In kdump we need build the network
> conf for it. I don't remember this clearly, need wait for Marc to check
> this.
>
> The reason I tried the exact route is some duplicate routes may exist in
> dracut. From dracut's point of view, it can handle route correctly if
> user can pass it the correct route. If duplicate routes are added,
> either we tolerate the warning message, or we require to change the
> implementation of dracut handling. But from dracut's side, they don't do
> anything wrong, why they need be changed.

I have found the following things that could each use a different route, 
and should be fully supported:
   * ssh/NFS/iscsi - but only one of these per configuration (as far as 
I know).
   * Name resolution (/etc/resolv.conf specifies this)
   * Heartbeat

I am not sure if we support:
   NIS (YP)

Additionally, customers could access the network through their own 
scripts, but it would be reasonable to not set up networks specifically 
for this.

Regards,

Marc

[PATCH v3] save exact route to remote target

[Baoquan He]

On 09/05/14 at 10:18am, Marc Milgram wrote:
> Hi,
>
> Sorry for the late response.
>
> On 08/21/2014 08:34 AM, Baoquan He wrote:
> > I think you are right about this. Since Marc said other modules could
> > use network too, such as heartbeat. In kdump we need build the network
> > conf for it. I don't remember this clearly, need wait for Marc to check
> > this.
> >
> > The reason I tried the exact route is some duplicate routes may exist in
> > dracut. From dracut's point of view, it can handle route correctly if
> > user can pass it the correct route. If duplicate routes are added,
> > either we tolerate the warning message, or we require to change the
> > implementation of dracut handling. But from dracut's side, they don't do
> > anything wrong, why they need be changed.

Hi Marc,

Re-read your mail, I am kind of confused.
> I have found the following things that could each use a different
> route, and should be fully supported:
> ssh/NFS/iscsi - but only one of these per configuration (as far
>
> as I know).

For above configuration, we can get route and add in 2nd kernel by kdump
scripts.
> Name resolution (/etc/resolv.conf specifies this)
> Heartbeat

For above 2, how do we handle them? And who will setup network
connections for them, especially Heartbeat?

Currently even previous design just add routes through a specific NIC.
If kdump script only take care of the NIC which dumping will go through,
but Heartbeat takes different path through different NIC, what will
happen? Is this related to static route issue and need be considered in
kdump scripts?

Thanks
Baoquan

[PATCH v3] save exact route to remote target

[Baoquan He]

Hi Marc,

When you come back, could you please help look at this issue when it's
convenient to you?

I remember in rhel6 originally I posted patch to fix static route on
exact route way. This is NACKed by you because in rhel6 the different
config can't be added to the same netdev. Since in handlenetdev() it
will check if the process is related to a handled netdev. Then you
posted patch on a new way that all routes going through that netdev are
saved and added into 2nd kernel.

If above what I remember is correct, then the exact route way can solve
the problems you mentioned there's a complex network environment which
customers is encountering, such as at the same time the heartbeats,
kdump and other usage. Then now we need go back to the old way I
suggested for rhel7/fedora, the exact route way. The reason as I have
replied to Vivek, is the route adding in 2nd kernel is handled in
Dracut. If we add all routes related to a netdev, then there could be
many duplicate routes, repeatedly adding them can cause warning message
printed, user may be not comfortable and think it's a bug. If I asked to
change the route adding in dracut, Harald may be not happy, because
duplicate is not their fault. So if exact route could solve the complex
network issue, I would like to sove it using exact route way.

Please help have a look at it if you have time. We plan to add this fix
into rhel7.1.

Thanks
Baoquan

On 08/18/14 at 04:34pm, Baoquan He wrote:
> Previously for solving static route issues, all routes which go
> through a specific dev will be saved in 1st kernel, and then added
> in 2nd kernel. Because we use below search pattern, an exception
> will happen:
> /sbin/ip route show | grep -v default | grep "^[[:digit:]].*via.* $_netdev"
>
> That exception is a corner case which happened when 2 machines connected
> directly by cable and the 2 network interfaces are configured in
> different network subnets. E.g there are 2 machines A and B:
>
> A:ens10 < ------ > B:ens9
>
> A:ens10  inet 192.168.100.111/24 scope global ens10
> route need be added in A:
> 192.168.110.0/24 dev ens10
>
> B:ens9   inet 192.168.110.222/24 scope global ens9
> route need be added in B
> 192.168.100.0/24 dev ens9
>
> Now if A want to dump to B, the route "192.168.110.0/24 dev ens10"
> has to be saved and added in 2nd kernel.
>
> So in this patch "ip route get to $target" command is executed, then
> an exact route can be got for going to that target. By this, static
> route works and the corner case can be fixed too.
> Signed-off-by: Baoquan He
>
> dracut-module-setup.sh | 31 +++++++++++++++++++++++--------
>  1 file changed, 23 insertions(+), 8 deletions(-)
>
> diff --git a/dracut-module-setup.sh b/dracut-module-setup.sh
> index 02a0557..9da1a41 100755
> --- a/dracut-module-setup.sh
> +++ b/dracut-module-setup.sh
> @@ -79,11 +79,6 @@ kdump_static_ip() {
>         _gateway=$(ip route list dev $_netdev | awk '/^default /{print $3}')
>         echo -n "${_srcaddr}::${_gateway}:${_netmask}::"
>      fi
> /sbin/ip route show | grep -v default | grep "^[[:digit:]].*via.* $_netdev " |\
> while read line; do
>    echo $line | awk '{printf("rd.route=%s:%s:%s\n", $1, $3, $5)}'
> done >> ${initdir}/etc/cmdline.d/45route-static.conf
>
> }
>
> kdump_get_mac_addr() {
> @@ -212,9 +207,27 @@ kdump_setup_znet() {
>      echo rd.znet=${NETTYPE},${SUBCHANNELS}${_options} > ${initdir}/etc/cmdline.d/30znet.conf
>  }
>
> +get_routes() {
> local _netdev="$1" _target="$2"
> local _route
> _route=`/sbin/ip route get to $_target 2>&1`
> if /sbin/ip route get to $_target | grep "via";
> then
>    # route going to a different subnet via a router
>    echo $_route | awk '{printf("rd.route=%s:%s:%s\n", $1, $3, $5)}' \
>        >> ${initdir}/etc/cmdline.d/45route-static.conf
> else
>    # route going to a different subnet though directly connected
>    echo $_route | awk '{printf("rd.route=%s::%s\n", $1, $3)}' \
>        >> ${initdir}/etc/cmdline.d/45route-static.conf
> fi
>
> +}
>
> # Setup dracut to bringup a given network interface
>  kdump_setup_netdev() {
> local _netdev=$1 _srcaddr=$2
>
> local _netdev=$1 _srcaddr=$2 _target=$3
> local _static _proto _ip_conf _ip_opts _ifname_opts
>
> if [ "$(uname -m)" = "s390x" ]; then
>
> @@ -229,6 +242,8 @@ kdump_setup_netdev() {
>          _proto=dhcp
>      fi
> get_routes $_netdev $_target
> _ip_conf="${initdir}/etc/cmdline.d/40ip.conf"
>    _ip_opts=" ip=${_static}$(kdump_setup_ifname $_netdev):${_proto}"
>
> @@ -281,7 +296,7 @@ kdump_install_net() {
>          _netdev=`echo $_netdev|awk '{print $3}'|head -n 1`
>      fi
> kdump_setup_netdev "${_netdev}" "${_srcaddr}"
>
> kdump_setup_netdev "${_netdev}" "${_srcaddr}" "${_server}"
>
> #save netdev used for kdump as cmdline
> # Whoever calling kdump_install_net() is setting up the default gateway,
>
> @@ -439,7 +454,7 @@ kdump_setup_iscsi_device() {
>      srcaddr=$(echo $netdev | awk '{ print $3; exit }')
>      netdev=$(echo $netdev | awk '{ print $1; exit }')
> kdump_setup_netdev $netdev $srcaddr
>
> kdump_setup_netdev $netdev $srcaddr $tgt_ipaddr
>
> # prepare netroot= command line
> # FIXME: IPV6 addresses require explicit [] around $tgt_ipaddr
>
> -- 
> 1.9.0
>
> kexec mailing list
> [e-mail]
> https://lists.fedoraproject.org/mailman/listinfo/kexec

[PATCH v3] save exact route to remote target

[WANG Chao]

On 08/18/14 at 04:34pm, Baoquan He wrote:
> Previously for solving static route issues, all routes which go
> through a specific dev will be saved in 1st kernel, and then added
> in 2nd kernel. Because we use below search pattern, an exception
> will happen:
> /sbin/ip route show | grep -v default | grep "^[[:digit:]].*via.* $_netdev"
>
> That exception is a corner case which happened when 2 machines connected
> directly by cable and the 2 network interfaces are configured in
> different network subnets. E.g there are 2 machines A and B:
>
> A:ens10 < ------ > B:ens9
>
> A:ens10  inet 192.168.100.111/24 scope global ens10
> route need be added in A:
> 192.168.110.0/24 dev ens10
>
> B:ens9   inet 192.168.110.222/24 scope global ens9
> route need be added in B
> 192.168.100.0/24 dev ens9
>
> Now if A want to dump to B, the route "192.168.110.0/24 dev ens10"
> has to be saved and added in 2nd kernel.
>
> So in this patch "ip route get to $target" command is executed, then
> an exact route can be got for going to that target. By this, static
> route works and the corner case can be fixed too.
>
> Signed-off-by: Baoquan He

I think we can clean up a bit for the part of determing subnet. See
my inline comment below. Because this patch has been sitting in the mail
list for quite long, I'll merge this patch and leave the cleanup part
for Bao or someone else to address later.

Acked-by: WANG Chao
> dracut-module-setup.sh | 31 +++++++++++++++++++++++--------
>  1 file changed, 23 insertions(+), 8 deletions(-)
>
> diff --git a/dracut-module-setup.sh b/dracut-module-setup.sh
> index 02a0557..9da1a41 100755
> --- a/dracut-module-setup.sh
> +++ b/dracut-module-setup.sh
> @@ -79,11 +79,6 @@ kdump_static_ip() {
>         _gateway=$(ip route list dev $_netdev | awk '/^default /{print $3}')
>         echo -n "${_srcaddr}::${_gateway}:${_netmask}::"
>      fi
> /sbin/ip route show | grep -v default | grep "^[[:digit:]].*via.* $_netdev " |\
> while read line; do
>    echo $line | awk '{printf("rd.route=%s:%s:%s\n", $1, $3, $5)}'
> done >> ${initdir}/etc/cmdline.d/45route-static.conf
>
> }
>
> kdump_get_mac_addr() {
> @@ -212,9 +207,27 @@ kdump_setup_znet() {
>      echo rd.znet=${NETTYPE},${SUBCHANNELS}${_options} > ${initdir}/etc/cmdline.d/30znet.conf
>  }
>
> +get_routes() {
> local _netdev="$1" _target="$2"
> local _route
> _route=`/sbin/ip route get to $_target 2>&1`
> if /sbin/ip route get to $_target | grep "via";
> then
>    # route going to a different subnet via a router
>    echo $_route | awk '{printf("rd.route=%s:%s:%s\n", $1, $3, $5)}' \
>        >> ${initdir}/etc/cmdline.d/45route-static.conf
> else
>    # route going to a different subnet though directly connected
>    echo $_route | awk '{printf("rd.route=%s::%s\n", $1, $3)}' \
>        >> ${initdir}/etc/cmdline.d/45route-static.conf
> fi

The logic of determining subnet is used twice in dracut-module-setup.sh,
the other instance is in kdump_install_net(). We can extract a function
for both places to use.

Thanks
WANG Chao

[Vivek Goyal]

Hi Bao,

Where is the patch. I only see changelog?

Thanks
Vivek

On Mon, Aug 18, 2014 at 04:34:52PM +0800, Baoquan He wrote:
> Previously for fixing the static route problem, all routes get through
> a specific network interface will be saved and added in 2nd kernel.
> Search pattern is used to get routes:
> /sbin/ip route show | grep -v default | grep "^[[:digit:]].*via.* $_netdev"
>
> An exception existed though, that is 2 machines connected directly and the
> network interfaces wihch are configured as in different network subnets.
>
> So in the v1 and v2, "ip route get to $target" command is executed and an
> exact route to a target is saved and added in 2nd kernel. This works for
> static route issue and can fix the corner case above.
>
> v1:
>     Introduced the new way which get exact route to remote target.
>
> v1->v2:
>     Since a grammer error which saved exact route, v2 is posted.
>
> v2->v3:
>     Per Vivek's comment, route to target should not be related to
>     static ip issues. So in v3 introduced the get_routes function
>     and take it out of kdump_static_ip.
>
> Baoquan He (1):
>   save exact route to remote target
>
> dracut-module-setup.sh | 31 +++++++++++++++++++++++--------
>  1 file changed, 23 insertions(+), 8 deletions(-)
>
> -- 
> 1.9.0

[Baoquan He]

On 08/18/14 at 01:24pm, Vivek Goyal wrote:
> Hi Bao,
>
> Where is the patch. I only see changelog?

I used the "git format-patch -1 --cover-letter" to get patch and its
cover letter. Seems that it didn't add the patch0/1 and patch1/1
automatically. This is the cover letter produced by git.

Please see the other one in the same thread, it is the patch1/1.
> Thanks
> Vivek
>
> On Mon, Aug 18, 2014 at 04:34:52PM +0800, Baoquan He wrote:
> > Previously for fixing the static route problem, all routes get through
> > a specific network interface will be saved and added in 2nd kernel.
> > Search pattern is used to get routes:
> > /sbin/ip route show | grep -v default | grep "^[[:digit:]].*via.* $_netdev"
> >
> > An exception existed though, that is 2 machines connected directly and the
> > network interfaces wihch are configured as in different network subnets.
> >
> > So in the v1 and v2, "ip route get to $target" command is executed and an
> > exact route to a target is saved and added in 2nd kernel. This works for
> > static route issue and can fix the corner case above.
> >
> > v1:
> >     Introduced the new way which get exact route to remote target.
> >
> > v1->v2:
> >     Since a grammer error which saved exact route, v2 is posted.
> >
> > v2->v3:
> >     Per Vivek's comment, route to target should not be related to
> >     static ip issues. So in v3 introduced the get_routes function
> >     and take it out of kdump_static_ip.
> >
> > Baoquan He (1):
> >   save exact route to remote target
> >
> > dracut-module-setup.sh | 31 +++++++++++++++++++++++--------
> >  1 file changed, 23 insertions(+), 8 deletions(-)
> >
> > -- 
> > 1.9.0

[Vivek Goyal]

On Tue, Aug 19, 2014 at 10:09:26AM +0800, Baoquan He wrote:
> On 08/18/14 at 01:24pm, Vivek Goyal wrote:
> > Hi Bao,
> >
> > Where is the patch. I only see changelog?
>
> I used the "git format-patch -1 --cover-letter" to get patch and its
> cover letter. Seems that it didn't add the patch0/1 and patch1/1
> automatically. This is the cover letter produced by git.
>
> Please see the other one in the same thread, it is the patch1/1.

I think you also need to use option -n so that your patches are numbered.
It is very important in a series. Otherwise it is very confusing.

Vivek
> > Thanks
> > Vivek
> >
> > On Mon, Aug 18, 2014 at 04:34:52PM +0800, Baoquan He wrote:
> > > Previously for fixing the static route problem, all routes get through
> > > a specific network interface will be saved and added in 2nd kernel.
> > > Search pattern is used to get routes:
> > > /sbin/ip route show | grep -v default | grep "^[[:digit:]].*via.* $_netdev"
> > >
> > > An exception existed though, that is 2 machines connected directly and the
> > > network interfaces wihch are configured as in different network subnets.
> > >
> > > So in the v1 and v2, "ip route get to $target" command is executed and an
> > > exact route to a target is saved and added in 2nd kernel. This works for
> > > static route issue and can fix the corner case above.
> > >
> > > v1:
> > >     Introduced the new way which get exact route to remote target.
> > >
> > > v1->v2:
> > >     Since a grammer error which saved exact route, v2 is posted.
> > >
> > > v2->v3:
> > >     Per Vivek's comment, route to target should not be related to
> > >     static ip issues. So in v3 introduced the get_routes function
> > >     and take it out of kdump_static_ip.
> > >
> > > Baoquan He (1):
> > >   save exact route to remote target
> > >
> > > dracut-module-setup.sh | 31 +++++++++++++++++++++++--------
> > >  1 file changed, 23 insertions(+), 8 deletions(-)
> > >
> > > -- 
> > > 1.9.0
>
> kexec mailing list
> [e-mail]
> https://lists.fedoraproject.org/mailman/listinfo/kexec

[Baoquan He]

On 08/20/14 at 10:29am, Vivek Goyal wrote:
> On Tue, Aug 19, 2014 at 10:09:26AM +0800, Baoquan He wrote:
> > On 08/18/14 at 01:24pm, Vivek Goyal wrote:
> > > Hi Bao,
> > >
> > > Where is the patch. I only see changelog?
> >
> > I used the "git format-patch -1 --cover-letter" to get patch and its
> > cover letter. Seems that it didn't add the patch0/1 and patch1/1
> > automatically. This is the cover letter produced by git.
> >
> > Please see the other one in the same thread, it is the patch1/1.
>
> I think you also need to use option -n so that your patches are numbered.
> It is very important in a series. Otherwise it is very confusing.

Yeah, for this kind of only 1 patch with 1 cover-letter, option -n need
be specified. Usually when 2 or more than 2 patches are produced, they
are numbered automatically.

Thanks for your notice. I just made this kind of patch set first time.
> Vivek

[Marc Milgram]

On 08/18/2014 04:34 AM, Baoquan He wrote:
> Previously for fixing the static route problem, all routes get through
> a specific network interface will be saved and added in 2nd kernel.
> Search pattern is used to get routes:
> /sbin/ip route show | grep -v default | grep "^[[:digit:]].*via.* $_netdev"
>
> An exception existed though, that is 2 machines connected directly and the
> network interfaces wihch are configured as in different network subnets.
>
> So in the v1 and v2, "ip route get to $target" command is executed and an
> exact route to a target is saved and added in 2nd kernel. This works for
> static route issue and can fix the corner case above.
>
> v1:
>      Introduced the new way which get exact route to remote target.
>
> v1->v2:
>      Since a grammer error which saved exact route, v2 is posted.
>
> v2->v3:
>      Per Vivek's comment, route to target should not be related to
>      static ip issues. So in v3 introduced the get_routes function
>      and take it out of kdump_static_ip.
>
> Baoquan He (1):
>    save exact route to remote target
>
> dracut-module-setup.sh | 31 +++++++++++++++++++++++--------
>   1 file changed, 23 insertions(+), 8 deletions(-)

Sorry for the very late response...

It looks like the first change was applied by another change.  Otherwise 
this looks good.

Marc

[Baoquan He]

On 10/22/14 at 11:14am, Marc Milgram wrote:
> On 08/18/2014 04:34 AM, Baoquan He wrote:
> > Previously for fixing the static route problem, all routes get through
> > a specific network interface will be saved and added in 2nd kernel.
> > Search pattern is used to get routes:
> > /sbin/ip route show | grep -v default | grep "^[[:digit:]].*via.* $_netdev"
> >
> > An exception existed though, that is 2 machines connected directly and the
> > network interfaces wihch are configured as in different network subnets.
> >
> > So in the v1 and v2, "ip route get to $target" command is executed and an
> > exact route to a target is saved and added in 2nd kernel. This works for
> > static route issue and can fix the corner case above.
> >
> > v1:
> >     Introduced the new way which get exact route to remote target.
> >
> > v1->v2:
> >     Since a grammer error which saved exact route, v2 is posted.
> >
> > v2->v3:
> >     Per Vivek's comment, route to target should not be related to
> >     static ip issues. So in v3 introduced the get_routes function
> >     and take it out of kdump_static_ip.
> >
> > Baoquan He (1):
> >   save exact route to remote target
> >
> > dracut-module-setup.sh | 31 +++++++++++++++++++++++--------
> >  1 file changed, 23 insertions(+), 8 deletions(-)
>
> Sorry for the very late response...
>
> It looks like the first change was applied by another change.
> Otherwise this looks good.

Hi Marc,

The patch can be applied without any conflict. I didn't got the first
change you mentioned, do you mean the change in this patch?

Thanks
Baoquan

[Marc Milgram]

On 10/26/2014 10:21 PM, Baoquan He wrote:
> On 10/22/14 at 11:14am, Marc Milgram wrote:
> > On 08/18/2014 04:34 AM, Baoquan He wrote:
> > > Previously for fixing the static route problem, all routes get through
> > > a specific network interface will be saved and added in 2nd kernel.
> > > Search pattern is used to get routes:
> > > /sbin/ip route show | grep -v default | grep "^[[:digit:]].*via.* $_netdev"
> > >
> > > An exception existed though, that is 2 machines connected directly and the
> > > network interfaces wihch are configured as in different network subnets.
> > >
> > > So in the v1 and v2, "ip route get to $target" command is executed and an
> > > exact route to a target is saved and added in 2nd kernel. This works for
> > > static route issue and can fix the corner case above.
> > >
> > > v1:
> > >      Introduced the new way which get exact route to remote target.
> > >
> > > v1->v2:
> > >      Since a grammer error which saved exact route, v2 is posted.
> > >
> > > v2->v3:
> > >      Per Vivek's comment, route to target should not be related to
> > >      static ip issues. So in v3 introduced the get_routes function
> > >      and take it out of kdump_static_ip.
> > >
> > > Baoquan He (1):
> > >    save exact route to remote target
> > >
> > > dracut-module-setup.sh | 31 +++++++++++++++++++++++--------
> > >   1 file changed, 23 insertions(+), 8 deletions(-)
> >
> > Sorry for the very late response...
> >
> > It looks like the first change was applied by another change.
> > Otherwise this looks good.
>
> Hi Marc,
>
> The patch can be applied without any conflict. I didn't got the first
> change you mentioned, do you mean the change in this patch?
>
> Thanks
> Baoquan

I had the wrong version checked out.

I checked out the master version, and the patch applies without conflict.

ACK