net: ipconfig: move ic_nameservers_fallback into #ifdef block

The new variable is only used when IPCONFIG_BOOTP is defined and otherwise
causes a warning:

net/ipv4/ipconfig.c:177:12: error: 'ic_nam

net: ipconfig: move ic_nameservers_fallback into #ifdef block

The new variable is only used when IPCONFIG_BOOTP is defined and otherwise
causes a warning:

net/ipv4/ipconfig.c:177:12: error: 'ic_nameservers_fallback' defined but not used [-Werror=unused-variable]

Move it next to the user.

Fixes: 81ac2722fa19 ("net: ipconfig: Allow DNS to be overwritten by DHCPACK")
Signed-off-by: Arnd Bergmann <[email protected]>
Reviewed-by: Simon Horman <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

show more ...

net: ipconfig: Allow DNS to be overwritten by DHCPACK

Some DHCP server implementations only send the important requested DHCP
options in the final BOOTP reply (DHCPACK).
One example is systemd-netwo

net: ipconfig: Allow DNS to be overwritten by DHCPACK

Some DHCP server implementations only send the important requested DHCP
options in the final BOOTP reply (DHCPACK).
One example is systemd-networkd.
However, RFC2131, in section 4.3.1 states:

> The server MUST return to the client:
> [...]
> o Parameters requested by the client, according to the following
> rules:
>
> -- IF the server has been explicitly configured with a default
> value for the parameter, the server MUST include that value
> in an appropriate option in the 'option' field, ELSE

I've reported the issue here:
https://github.com/systemd/systemd/issues/27471

Linux PNP DHCP client implementation only takes into account the DNS
servers received in the first BOOTP reply (DHCPOFFER).
This usually isn't an issue as servers are required to put the same
values in the DHCPOFFER and DHCPACK.
However, RFC2131, in section 4.3.2 states:

> Any configuration parameters in the DHCPACK message SHOULD NOT
> conflict with those in the earlier DHCPOFFER message to which the
> client is responding. The client SHOULD use the parameters in the
> DHCPACK message for configuration.

When making Linux PNP DHCP client (cmdline ip=dhcp) interact with
systemd-networkd DHCP server, an interesting "protocol misunderstanding"
happens:
Because DNS servers were only specified in the DHCPACK and not in the
DHCPOFFER, Linux will not catch the correct DNS servers: in the first
BOOTP reply (DHCPOFFER), it sees that there is no DNS, and sets as
fallback the IP of the DHCP server itself. When the second BOOTP reply
comes (DHCPACK), it's already too late: the kernel will not overwrite
the fallback setting it has set previously.

This patch makes the kernel overwrite its DNS fallback by DNS servers
specified in the DHCPACK if any.

Signed-off-by: Martin Wetterwald <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

show more ...

net: ipconfig: use strscpy to replace strlcpy

The strlcpy should not be used because it doesn't limit the source
length. Preferred is strscpy.

Signed-off-by: XueBing Chen <[email protected]>
Sign

net: ipconfig: use strscpy to replace strlcpy

The strlcpy should not be used because it doesn't limit the source
length. Preferred is strscpy.

Signed-off-by: XueBing Chen <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

show more ...

net: ipconfig: Relax fw_devlink if we need to mount a network rootfs

If there are network devices that could probe without some of their
suppliers probing and those network devices are needed to mou

net: ipconfig: Relax fw_devlink if we need to mount a network rootfs

If there are network devices that could probe without some of their
suppliers probing and those network devices are needed to mount a
network rootfs, then fw_devlink=on might break that usecase by blocking
the network devices from probing by the time IP auto config starts.

So, if no network devices are available when IP auto config is enabled
and we have a network rootfs, make sure fw_devlink doesn't block the
probing of any device that has a driver and then retry finding a network
device.

Tested-by: Geert Uytterhoeven <[email protected]>
Signed-off-by: Saravana Kannan <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

show more ...

net: ipconfig: Release the rtnl_lock while waiting for carrier

While waiting for a carrier to come on one of the netdevices, some
devices will require to take the rtnl lock at some point to fully
in

net: ipconfig: Release the rtnl_lock while waiting for carrier

While waiting for a carrier to come on one of the netdevices, some
devices will require to take the rtnl lock at some point to fully
initialize all parts of the link.

That's the case for SFP, where the rtnl is taken when a module gets
detected. This prevents mounting an NFS rootfs over an SFP link.

This means that while ipconfig waits for carriers to be detected, no SFP
modules can be detected in the meantime, it's only detected after
ipconfig times out.

This commit releases the rtnl_lock while waiting for the carrier to come
up, and re-takes it to check the for the init device and carrier status.

Signed-off-by: Maxime Chevallier <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

show more ...

net: ipconfig: Don't override command-line hostnames or domains

If the user specifies a hostname or domain name as part of the ip=
command-line option, preserve it and don't overwrite it with one
su

net: ipconfig: Don't override command-line hostnames or domains

If the user specifies a hostname or domain name as part of the ip=
command-line option, preserve it and don't overwrite it with one
supplied by DHCP/BOOTP.

For instance, ip=::::myhostname::dhcp will use "myhostname" rather than
ignoring and overwriting it.

Fix the comment on ic_bootp_string that suggests it only copies a string
"if not already set"; it doesn't have any such logic.

Signed-off-by: Josh Triplett <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

show more ...

net: ipconfig: ic_dev can be NULL in ic_close_devs

ic_close_dev contains a generalization of the logic to not close a
network interface if it's the host port for a DSA switch. This logic is
disguise

net: ipconfig: ic_dev can be NULL in ic_close_devs

ic_close_dev contains a generalization of the logic to not close a
network interface if it's the host port for a DSA switch. This logic is
disguised behind an iteration through the lowers of ic_dev in
ic_close_dev.

When no interface for ipconfig can be found, ic_dev is NULL, and
ic_close_dev:
- dereferences a NULL pointer when assigning selected_dev
- would attempt to search through the lower interfaces of a NULL
net_device pointer

So we should protect against that case.

The "lower_dev" iterator variable was shortened to "lower" in order to
keep the 80 character limit.

Fixes: f68cbaed67cb ("net: ipconfig: avoid use-after-free in ic_close_devs")
Fixes: 46acf7bdbc72 ("Revert "net: ipv4: handle DSA enabled master network devices"")
Signed-off-by: Vladimir Oltean <[email protected]>
Tested-by: Heiko Thiery <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

show more ...

net: ipconfig: avoid use-after-free in ic_close_devs

Due to the fact that ic_dev->dev is kept open in ic_close_dev, I had
thought that ic_dev will not be freed either. But that is not the case,
but

net: ipconfig: avoid use-after-free in ic_close_devs

Due to the fact that ic_dev->dev is kept open in ic_close_dev, I had
thought that ic_dev will not be freed either. But that is not the case,
but instead "everybody dies" when ipconfig cleans up, and just the
net_device behind ic_dev->dev remains allocated but not ic_dev itself.

This is a problem because in ic_close_devs, for every net device that
we're about to close, we compare it against the list of lower interfaces
of ic_dev, to figure out whether we should close it or not. But since
ic_dev itself is subject to freeing, this means that at some point in
the middle of the list of ipconfig interfaces, ic_dev will have been
freed, and we would be still attempting to iterate through its list of
lower interfaces while checking whether to bring down the remaining
ipconfig interfaces.

There are multiple ways to avoid the use-after-free: we could delay
freeing ic_dev until the very end (outside the while loop). Or an even
simpler one: we can observe that we don't need ic_dev when iterating
through its lowers, only ic_dev->dev, structure which isn't ever freed.
So, by keeping ic_dev->dev in a variable assigned prior to freeing
ic_dev, we can avoid all use-after-free issues.

Fixes: 46acf7bdbc72 ("Revert "net: ipv4: handle DSA enabled master network devices"")
Reported-by: kernel test robot <[email protected]>
Signed-off-by: Vladimir Oltean <[email protected]>
Reviewed-by: Florian Fainelli <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

show more ...

Revert "net: ipv4: handle DSA enabled master network devices"

This reverts commit 728c02089a0e3eefb02e9927bfae50490f40e72e.

Since 2015 DSA has gained more integration with the network stack, we
can

Revert "net: ipv4: handle DSA enabled master network devices"

This reverts commit 728c02089a0e3eefb02e9927bfae50490f40e72e.

Since 2015 DSA has gained more integration with the network stack, we
can now have the same functionality without explicitly open-coding for
it:
- It now opens the DSA master netdevice automatically whenever a user
netdevice is opened.
- The master and switch interfaces are coupled in an upper/lower
hierarchy using the netdev adjacency lists.

In the nfsroot example below, the interface chosen by autoconfig was
swp3, and every interface except that and the DSA master, eth1, was
brought down afterwards:

[ 8.714215] mscc_felix 0000:00:00.5 swp0 (uninitialized): PHY [0000:00:00.3:10] driver [Microsemi GE VSC8514 SyncE] (irq=POLL)
[ 8.978041] mscc_felix 0000:00:00.5 swp1 (uninitialized): PHY [0000:00:00.3:11] driver [Microsemi GE VSC8514 SyncE] (irq=POLL)
[ 9.246134] mscc_felix 0000:00:00.5 swp2 (uninitialized): PHY [0000:00:00.3:12] driver [Microsemi GE VSC8514 SyncE] (irq=POLL)
[ 9.486203] mscc_felix 0000:00:00.5 swp3 (uninitialized): PHY [0000:00:00.3:13] driver [Microsemi GE VSC8514 SyncE] (irq=POLL)
[ 9.512827] mscc_felix 0000:00:00.5: configuring for fixed/internal link mode
[ 9.521047] mscc_felix 0000:00:00.5: Link is Up - 2.5Gbps/Full - flow control off
[ 9.530382] device eth1 entered promiscuous mode
[ 9.535452] DSA: tree 0 setup
[ 9.539777] printk: console [netcon0] enabled
[ 9.544504] netconsole: network logging started
[ 9.555047] fsl_enetc 0000:00:00.2 eth1: configuring for fixed/internal link mode
[ 9.562790] fsl_enetc 0000:00:00.2 eth1: Link is Up - 1Gbps/Full - flow control off
[ 9.564661] 8021q: adding VLAN 0 to HW filter on device bond0
[ 9.637681] fsl_enetc 0000:00:00.0 eth0: PHY [0000:00:00.0:02] driver [Qualcomm Atheros AR8031/AR8033] (irq=POLL)
[ 9.655679] fsl_enetc 0000:00:00.0 eth0: configuring for inband/sgmii link mode
[ 9.666611] mscc_felix 0000:00:00.5 swp0: configuring for inband/qsgmii link mode
[ 9.676216] 8021q: adding VLAN 0 to HW filter on device swp0
[ 9.682086] mscc_felix 0000:00:00.5 swp1: configuring for inband/qsgmii link mode
[ 9.690700] 8021q: adding VLAN 0 to HW filter on device swp1
[ 9.696538] mscc_felix 0000:00:00.5 swp2: configuring for inband/qsgmii link mode
[ 9.705131] 8021q: adding VLAN 0 to HW filter on device swp2
[ 9.710964] mscc_felix 0000:00:00.5 swp3: configuring for inband/qsgmii link mode
[ 9.719548] 8021q: adding VLAN 0 to HW filter on device swp3
[ 9.747811] Sending DHCP requests ..
[ 12.742899] mscc_felix 0000:00:00.5 swp1: Link is Up - 1Gbps/Full - flow control rx/tx
[ 12.743828] mscc_felix 0000:00:00.5 swp0: Link is Up - 1Gbps/Full - flow control off
[ 12.747062] IPv6: ADDRCONF(NETDEV_CHANGE): swp1: link becomes ready
[ 12.755216] fsl_enetc 0000:00:00.0 eth0: Link is Up - 1Gbps/Full - flow control rx/tx
[ 12.766603] IPv6: ADDRCONF(NETDEV_CHANGE): swp0: link becomes ready
[ 12.783188] mscc_felix 0000:00:00.5 swp2: Link is Up - 1Gbps/Full - flow control rx/tx
[ 12.785354] IPv6: ADDRCONF(NETDEV_CHANGE): eth0: link becomes ready
[ 12.799535] IPv6: ADDRCONF(NETDEV_CHANGE): swp2: link becomes ready
[ 13.803141] mscc_felix 0000:00:00.5 swp3: Link is Up - 1Gbps/Full - flow control rx/tx
[ 13.811646] IPv6: ADDRCONF(NETDEV_CHANGE): swp3: link becomes ready
[ 15.452018] ., OK
[ 15.470336] IP-Config: Got DHCP answer from 10.0.0.1, my address is 10.0.0.39
[ 15.477887] IP-Config: Complete:
[ 15.481330] device=swp3, hwaddr=00:04:9f:05:de:0a, ipaddr=10.0.0.39, mask=255.255.255.0, gw=10.0.0.1
[ 15.491846] host=10.0.0.39, domain=(none), nis-domain=(none)
[ 15.498429] bootserver=10.0.0.1, rootserver=10.0.0.1, rootpath=
[ 15.498481] nameserver0=8.8.8.8
[ 15.627542] fsl_enetc 0000:00:00.0 eth0: Link is Down
[ 15.690903] mscc_felix 0000:00:00.5 swp0: Link is Down
[ 15.745216] mscc_felix 0000:00:00.5 swp1: Link is Down
[ 15.800498] mscc_felix 0000:00:00.5 swp2: Link is Down

Signed-off-by: Vladimir Oltean <[email protected]>
Reviewed-by: Andrew Lunn <[email protected]>
Reviewed-by: Florian Fainelli <[email protected]>
Signed-off-by: Jakub Kicinski <[email protected]>

show more ...

net: ipconfig: Avoid spurious blank lines in boot log

When dumping the name and NTP servers advertised by DHCP, a blank line
is emitted if either of the lists is empty. This can lead to confusing
is

net: ipconfig: Avoid spurious blank lines in boot log

When dumping the name and NTP servers advertised by DHCP, a blank line
is emitted if either of the lists is empty. This can lead to confusing
issues such as the blank line getting flagged as warning. This happens
because the blank line is the result of pr_cont("\n") and that may see
its level corrupted by some other driver concurrently writing to the
console.

Fix this by making sure that the terminating newline is only emitted
if at least one entry in the lists was printed before.

Reported-by: Jon Hunter <[email protected]>
Signed-off-by: Thierry Reding <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>

show more ...

Documentation: nfsroot.rst: Fix references to nfsroot.rst

When converting and moving nfsroot.txt to nfsroot.rst the references to
the old text file was not updated to match the change, fix this.

Fi

Documentation: nfsroot.rst: Fix references to nfsroot.rst

When converting and moving nfsroot.txt to nfsroot.rst the references to
the old text file was not updated to match the change, fix this.

Fixes: f9a9349846f92b2d ("Documentation: nfsroot.txt: convert to ReST")
Signed-off-by: Niklas Söderlund <[email protected]>
Reviewed-by: Geert Uytterhoeven <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jonathan Corbet <[email protected]>

show more ...

proc: convert everything to "struct proc_ops"

The most notable change is DEFINE_SHOW_ATTRIBUTE macro split in
seq_file.h.

Conversion rule is:

llseek => proc_lseek
unlocked_ioctl => proc_ioctl

proc: convert everything to "struct proc_ops"

The most notable change is DEFINE_SHOW_ATTRIBUTE macro split in
seq_file.h.

Conversion rule is:

llseek => proc_lseek
unlocked_ioctl => proc_ioctl

xxx => proc_xxx

delete ".owner = THIS_MODULE" line

[[email protected]: fix drivers/isdn/capi/kcapi_proc.c]
[[email protected]: fix kernel/sched/psi.c]
Link: http://lkml.kernel.org/r/[email protected]
Link: http://lkml.kernel.org/r/20191225172546.GB13378@avx2
Signed-off-by: Alexey Dobriyan <[email protected]>
Signed-off-by: Stephen Rothwell <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

show more ...

net: ipconfig: Wait for deferred device probes

If network device drives are using deferred probing, it was possible
that waiting for devices to show up in ipconfig was already over,
when the device

net: ipconfig: Wait for deferred device probes

If network device drives are using deferred probing, it was possible
that waiting for devices to show up in ipconfig was already over,
when the device eventually showed up. By calling wait_for_device_probe()
we now make sure deferred probing is done before checking for available
devices.

Signed-off-by: Thomas Bogendoerfer <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

show more ...

ipconfig: Handle CONFIG_CIFS_ROOT option

The experimental root file system support in cifs.ko relies on
ipconfig to set up the network stack and then accessing the SMB share
that contains the rootfs

ipconfig: Handle CONFIG_CIFS_ROOT option

The experimental root file system support in cifs.ko relies on
ipconfig to set up the network stack and then accessing the SMB share
that contains the rootfs files.

Signed-off-by: Paulo Alcantara (SUSE) <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

show more ...

ipconfig: add carrier_timeout kernel parameter

commit 3fb72f1e6e61 ("ipconfig wait for carrier") added a
"wait for carrier" policy, with a fixed worst case maximum wait
of two minutes.

Now make the

ipconfig: add carrier_timeout kernel parameter

commit 3fb72f1e6e61 ("ipconfig wait for carrier") added a
"wait for carrier" policy, with a fixed worst case maximum wait
of two minutes.

Now make the wait for carrier timeout configurable on the kernel
commandline and use the 120s as the default.

The timeout messages introduced with
commit 5e404cd65860 ("ipconfig: add informative timeout messages while
waiting for carrier") are done in a fixed interval of 20 seconds, just
like they were before (240/12).

Signed-off-by: Martin Kepplinger <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

show more ...

ipconfig: convert to DEFINE_SHOW_ATTRIBUTE

Use DEFINE_SHOW_ATTRIBUTE macro to simplify the code.

Signed-off-by: Yangtao Li <[email protected]>
Signed-off-by: David S. Miller <[email protected]

ipconfig: convert to DEFINE_SHOW_ATTRIBUTE

Use DEFINE_SHOW_ATTRIBUTE macro to simplify the code.

Signed-off-by: Yangtao Li <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

show more ...

net: Allow class-e address assignment via ifconfig ioctl

While most distributions long ago switched to the iproute2 suite
of utilities, which allow class-e (240.0.0.0/4) address assignment,
distribu

net: Allow class-e address assignment via ifconfig ioctl

While most distributions long ago switched to the iproute2 suite
of utilities, which allow class-e (240.0.0.0/4) address assignment,
distributions relying on busybox, toybox and other forms of
ifconfig cannot assign class-e addresses without this kernel patch.

While CIDR has been obsolete for 2 decades, and a survey of all the
open source code in the world shows the IN_whatever macros are also
obsolete... rather than obsolete CIDR from this ioctl entirely, this
patch merely enables class-e assignment, sanely.

Signed-off-by: Dave Taht <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

show more ...

net: core: dev: Add extack argument to dev_change_flags()

In order to pass extack together with NETDEV_PRE_UP notifications, it's
necessary to route the extack to __dev_open() from diverse (possibly

net: core: dev: Add extack argument to dev_change_flags()

In order to pass extack together with NETDEV_PRE_UP notifications, it's
necessary to route the extack to __dev_open() from diverse (possibly
indirect) callers. One prominent API through which the notification is
invoked is dev_change_flags().

Therefore extend dev_change_flags() with and extra extack argument and
update all users. Most of the calls end up just encoding NULL, but
several sites (VLAN, ipvlan, VRF, rtnetlink) do have extack available.

Since the function declaration line is changed anyway, name the other
function arguments to placate checkpatch.

Signed-off-by: Petr Machata <[email protected]>
Acked-by: Jiri Pirko <[email protected]>
Reviewed-by: Ido Schimmel <[email protected]>
Reviewed-by: David Ahern <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

show more ...

proc: introduce proc_create_single{,_data}

Variants of proc_create{,_data} that directly take a seq_file show
callback and drastically reduces the boilerplate code in the callers.

All trivial calle

proc: introduce proc_create_single{,_data}

Variants of proc_create{,_data} that directly take a seq_file show
callback and drastically reduces the boilerplate code in the callers.

All trivial callers converted over.

Signed-off-by: Christoph Hellwig <[email protected]>

show more ...

net: ipv4: ipconfig: fix unused variable

When CONFIG_PROC_FS isn't set, variable ipconfig_dir isn't used.
net/ipv4/ipconfig.c:167:31: warning: ‘ipconfig_dir’ defined but not used [-Wunused-variable]

net: ipv4: ipconfig: fix unused variable

When CONFIG_PROC_FS isn't set, variable ipconfig_dir isn't used.
net/ipv4/ipconfig.c:167:31: warning: ‘ipconfig_dir’ defined but not used [-Wunused-variable]
static struct proc_dir_entry *ipconfig_dir;
^~~~~~~~~~~~
Move the declaration of ipconfig_dir inside the CONFIG_PROC_FS ifdef to
fix the warning.

Fixes: c04d2cb2009f ("ipconfig: Write NTP server IPs to /proc/net/ipconfig/ntp_servers")
Signed-off-by: Anders Roxell <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

show more ...

ipconfig: Write NTP server IPs to /proc/net/ipconfig/ntp_servers

Distributed filesystems are most effective when the server and client
clocks are synchronised. Embedded devices often use NFS for the

ipconfig: Write NTP server IPs to /proc/net/ipconfig/ntp_servers

Distributed filesystems are most effective when the server and client
clocks are synchronised. Embedded devices often use NFS for their
root filesystem but typically do not contain an RTC, so the clocks of
the NFS server and the embedded device will be out-of-sync when the root
filesystem is mounted (and may not be synchronised until late in the
boot process).

Extend ipconfig with the ability to export IP addresses of NTP servers
it discovers to /proc/net/ipconfig/ntp_servers. They can be supplied as
follows:

- If ipconfig is configured manually via the "ip=" or "nfsaddrs="
kernel command line parameters, one NTP server can be specified in
the new "<ntp0-ip>" parameter.
- If ipconfig is autoconfigured via DHCP, request DHCP option 42 in
the DHCPDISCOVER message, and record the IP addresses of up to three
NTP servers sent by the responding DHCP server in the subsequent
DHCPOFFER message.

ipconfig will only write the NTP server IP addresses it discovers to
/proc/net/ipconfig/ntp_servers, one per line (in the order received from
the DHCP server, if DHCP autoconfiguration is used); making use of these
NTP servers is the responsibility of a user space process (e.g. an
initrd/initram script that invokes an NTP client before mounting an NFS
root filesystem).

Signed-off-by: Chris Novakovic <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

show more ...

ipconfig: Create /proc/net/ipconfig directory

To allow ipconfig to report IP configuration details to user space
processes without cluttering /proc/net, create a new subdirectory
/proc/net/ipconfig.

ipconfig: Create /proc/net/ipconfig directory

To allow ipconfig to report IP configuration details to user space
processes without cluttering /proc/net, create a new subdirectory
/proc/net/ipconfig. All files containing IP configuration details should
be written to this directory.

Signed-off-by: Chris Novakovic <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

show more ...

ipconfig: Correctly initialise ic_nameservers

ic_nameservers, which stores the list of name servers discovered by
ipconfig, is initialised (i.e. has all of its elements set to NONE, or
0xffffffff) b

ipconfig: Correctly initialise ic_nameservers

ic_nameservers, which stores the list of name servers discovered by
ipconfig, is initialised (i.e. has all of its elements set to NONE, or
0xffffffff) by ic_nameservers_predef() in the following scenarios:

- before the "ip=" and "nfsaddrs=" kernel command line parameters are
parsed (in ip_auto_config_setup());
- before autoconfiguring via DHCP or BOOTP (in ic_bootp_init()), in
order to clear any values that may have been set after parsing "ip="
or "nfsaddrs=" and are no longer needed.

This means that ic_nameservers_predef() is not called when neither "ip="
nor "nfsaddrs=" is specified on the kernel command line. In this
scenario, every element in ic_nameservers remains set to 0x00000000,
which is indistinguishable from ANY and causes pnp_seq_show() to write
the following (bogus) information to /proc/net/pnp:

#MANUAL
nameserver 0.0.0.0
nameserver 0.0.0.0
nameserver 0.0.0.0

This is potentially problematic for systems that blindly link
/etc/resolv.conf to /proc/net/pnp.

Ensure that ic_nameservers is also initialised when neither "ip=" nor
"nfsaddrs=" are specified by calling ic_nameservers_predef() in
ip_auto_config(), but only when ip_auto_config_setup() was not called
earlier. This causes the following to be written to /proc/net/pnp, and
is consistent with what gets written when ipconfig is configured
manually but no name servers are specified on the kernel command line:

#MANUAL

Signed-off-by: Chris Novakovic <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

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ipconfig: BOOTP: Request CONF_NAMESERVERS_MAX name servers

When ipconfig is autoconfigured via BOOTP, the request packet
initialised by ic_bootp_init_ext() always allocates 8 bytes for the name
serv

ipconfig: BOOTP: Request CONF_NAMESERVERS_MAX name servers

When ipconfig is autoconfigured via BOOTP, the request packet
initialised by ic_bootp_init_ext() always allocates 8 bytes for the name
server option, limiting the BOOTP server to responding with at most 2
name servers even though ipconfig in fact supports an arbitrary number
of name servers (as defined by CONF_NAMESERVERS_MAX, which is currently
3).

Only request name servers in the request packet if CONF_NAMESERVERS_MAX
is positive (to comply with [1, §3.8]), and allocate enough space in the
packet for CONF_NAMESERVERS_MAX name servers to indicate the maximum
number we can accept in response.

[1] RFC 2132, "DHCP Options and BOOTP Vendor Extensions":
https://tools.ietf.org/rfc/rfc2132.txt

Signed-off-by: Chris Novakovic <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

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ipconfig: BOOTP: Don't request IEN-116 name servers

When ipconfig is autoconfigured via BOOTP, the request packet
initialised by ic_bootp_init_ext() allocates 8 bytes for tag 5 ("Name
Server" [1, §3

ipconfig: BOOTP: Don't request IEN-116 name servers

When ipconfig is autoconfigured via BOOTP, the request packet
initialised by ic_bootp_init_ext() allocates 8 bytes for tag 5 ("Name
Server" [1, §3.7]), but tag 5 in the response isn't processed by
ic_do_bootp_ext(). Instead, allocate the 8 bytes to tag 6 ("Domain Name
Server" [1, §3.8]), which is processed by ic_do_bootp_ext(), and appears
to have been the intended tag to request.

This won't cause any breakage for existing users, as tag 5 responses
provided by BOOTP servers weren't being processed anyway.

[1] RFC 2132, "DHCP Options and BOOTP Vendor Extensions":
https://tools.ietf.org/rfc/rfc2132.txt

Signed-off-by: Chris Novakovic <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

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