If the attribute 'interface' is not set in a 'domain' tag, the router tries to
dynamically receive and maintain an IP configuration for that domain by using
DHCP in the client role at all interfaces that connect to the domain. In the
DHCP discover phase, the router simply chooses the first DHCP offer that
arrives. So, no comparison of different DHCP offers is done. In the DHCP
request phase, the server is expected to provide an IP address, a gateway, a
subnet mask, and an IP lease time to the router. If anything substantial goes
wrong during a DHCP exchange, the router discards the outcome of the exchange
and goes back to the DHCP discover phase. At any time where there is no valid
IP configuration present at a domain, the domain does only act as DHCP client
and all other router functionality is disabled for the domain. A domain cannot
act as DHCP client and DHCP server at once. So, a 'domain' tag must either
have an 'interface' attribute or must not contain a 'dhcp-server' tag.
Ref #2534
An IPv4 config (for a domain/interface of the router) consists of
an IPv4 address, a subnet prefix specifier, an optional gateway
IPv4 address, and some flags that declare whether these fields and
the config as a whole are valid. To make the handling of those
tightly connected values easier and less error prone, we encapsulate
them in a new class.
Ref #2534
Under certain circumstances we don't want inits state report to become too
outdated even if there is no change to its config or the sessions of its
children. This is the case if init is requested to provide a capability or RAM
info of it's children via its state report. Now, init automatically updates
the state report with each 1000 ms if the attribute 'child_caps' or
'child_ram' is positively set in the 'report' tag.
Timing itself costs time. Thus, the stressfull timeout phase of the
test is not exactly as long as set but a little bit longer. This is why the
fast timeouts are able to trigger more often than they are expected to
(the timer has a static timeout-rate limit). Normally we consider this effect
through an error tolerance of 10%. But at least on foc x86_32 (PIT with very
low max timeout), timing is so expensive that 10% is not enough. We have to
raise it to 11%.
This patch propages the 'Service_denied' condition of forwarded sessions
to the parent. Without it, the invalid session request stays pending
infinitely, which leads to the problem described in issue #2542. It
turns out that suggested solution given in the issue text is actually
not needed when applying this fix.
Fixes#2542
The ROM filter did not handle the situation where the generated content
exceeds the size of the initially allocated dataspace for the target
buffer. This patch wraps the XML generation in a retry loop that
expands the buffer as needed.
This patch makes the specification of screen coordinates more flexible.
First, the 'origin' attribute allows one to refer to either of the four
screen corners without knowing the screen size. Second, the 'width'
and 'height' values now accept negative values, which are relative to
the screen size.
This was an error output-line for each affected packet previously but it
is pretty normal for the router to receive packets whose network layer
protocol it doesn't know . In the default case, these packets shall be
ignored silently.
Ref #2490
One can configure the NIC router to act as DHCP server at interfaces of a
domain by adding the <dhcp> tag to the configuration of the domain like
this:
<domain name="vbox" interface="10.0.1.1/24">
<dhcp-server ip_first="10.0.1.80"
ip_last="10.0.1.100"
ip_lease_time_sec="3600"
dns_server="10.0.0.2"/>
...
</domain>
The attributes ip_first and ip_last define the available IPv4 address
range while ip_lease_time_sec defines the lifetime of an IPv4 address
assignment in seconds. The IPv4 address range must be in the subnet
defined by the interface attribute of the domain tag and must not cover
the IPv4 address in this attribute. The dns_server attribute gives the
IPv4 address of the DNS server that might also be in another subnet.
The lifetime of an offered assignment is the configured round trip time of
the router while the ip_lease_time_sec is applied only if the offer is
requested by the client in time.
The ports/run/virtualbox_nic_router.run script is an example of how to
use the new DHCP server functionality.
Ref #2490
Previously, garbage collect was only done when an incoming packet passed the
Ethernet checks. Now it is really done first when receiving a packet at an
interface.
Ref #2490
If the router has no gateway attribute for a domain (means that the router
itself is the gateway), and it gets an ARP request for a foreign IP, it shall
answer with its own IP.
Ref #2490
Do not use two times the RTT for the lifetime of links but use it as
it is configured to simplify the usage of the router. Internally, use
Microseconds/Duration type instead of plain integers.
Ref #2490
The nic_dump uses a wrapper for all supported protocols that
takes a packet and a verbosity configuration. The wrapper object can
than be used as argument for a Genode log function and prints the
packet's contents according to the given configuration. The
configuration is a distinct class to enable the reuse of one instance
for different packets.
There are currently 4 possible configurations for each protocol:
* NONE (no output for this protocol)
* SHORT (only the protocol name)
* COMPACT (the most important information densely packed)
* COMPREHENSIVE (all header information of this protocol)
Ref #2490
Provide utilities for appending new options to an existing DHCP packet
and a utility for finding existing options that returns a typed option
object. Remove old version that return untyped options.
Ref #2490
Apply the style rule that an accessor is named similar to the the underlying
value. Provide read and write accessors for each mandatory header attribute.
Fix some incorrect structure in the headers like with the flags field
in Ipv4_packet.
Ref #2490
Encapsulate the enum into a struct so that it is named
Ethernet_frame::Type::Enum, give it the correct storage type
uint16_t, and remove those values that are (AFAIK) not used by
now (genode, world).
Ref #2490
Do not stop routing if the transport layer protocol is unknown but
continue with trying IP routing instead. The latter was already
done when no transport routing could be applied but for unknown transport
protocols we caught the exception at the wrong place.
Ref #2490
No starvation of timeout signals
--------------------------------
Add several timeouts < 1ms to the stress test and check that timeout
handling doesn't become significantly unfair (starvation) in this situation
where some timeouts trigger nmuch faster than they get handled.
Rate limiting for timeout handling in timer
-------------------------------------------
Ensure that the timer does not handle timeouts again within 1000
microseconds after the last handling of timeouts. This makes denial of
service attacks harder. This commit does not limit the rate of timeout
signals handled inside the timer but it causes the timer to do it less
often. If a client continuously installs a very small timeout at the
timer it still causes a signal to be submitted to the timer each time
and some extra CPU time to be spent in the internal handling method. But
only every 1000 microseconds this internal handling causes user timeouts
to trigger.
If we would want to limit also the call of the internal handling method
to ensure that CPU time is spent beside the RPCs only every 1000
microseconds, things would get more complex. For instance, on NOVA
Time_source::schedule_timeout(0) must be called each time a new timeout
gets installed and becomes head of the scheduling queue. We cannot
simply overwrite the already running timeout with the new one.
Ref #2490
We did not set the correct now_period previously but it wasn't conspicuous
because the bug triggered not before a full period had passed which on most
platforms is a pretty long time.
Ref #2490
Ensure that the timer does not handle timeouts again within 1000
microseconds after the last handling of timeouts. This makes denial of
service attacks harder. This commit does not limit the rate of timeout
signals handled inside the timer but it causes the timer to do it less
often. If a client continuously installs a very small timeout at the
timer it still causes a signal to be submitted to the timer each time
and some extra CPU time to be spent in the internal handling method. But
only every 1000 microseconds this internal handling causes user timeouts
to trigger.
If we would want to limit also the call of the internal handling method
to ensure that CPU time is spent beside the RPCs only every 1000
microseconds, things would get more complex. For instance, on NOVA
Time_source::schedule_timeout(0) must be called each time a new timeout
gets installed and becomes head of the scheduling queue. We cannot
simply overwrite the already running timeout with the new one.
Ref #2490
We update the alarm-scheduler time with results of
Timer::Connection::curr_time when we schedule new timeouts but when
handling the signal from the Timer server we updated the alarm-scheduler
time with the result of Timer::Connection::elapsed_us. Mixing times
like this could cause a non-monotone time value in the alarm scheduler.
The alarm scheduler then thought that the time value wrapped and
triggered all timeouts immediately. The problem was fixed by always
using Timer::Connection::curr_time as time source.
Ref #2490
Create periodic and one-shot timeouts with the maximum duration
to see if triggers any corner-case bugs. They must not trigger during
the test.
Ref #2490
If we add an absolute timeout to the back-end alarm-scheduler we must first
call 'handle' at the scheduler to update its internal time value.
Otherwise, it might happen that we add a timeout who's deadline is so big that
it normally belongs to the next time-counter period but the scheduler thinks
that it belongs to the current period as its time is older than the one used
to calculate the deadline.
Ref #2490
When we have two time values of an unsigned integer type and we create
the difference and want to know wether it is positive or negative within
the same value we loose at least one half of the value range for casting
to signed integers. This was the case in the alarm scheduler when
checking wether an alarm already triggered. Even worse, we casted from
'unsigned long' to 'signed int' which caused further loss on at least
x86_64. Thus, big timeouts like ~0UL falsely triggered directly.
Now, we use an extra boolean value to remember in which period of the
time counter we are and to which period of the time counter the deadline
of an alarm belongs. This boolean switches its value each time the time
counter wraps. This way, we can avoid any casting by checking wether the
current time is of the same period as the deadline of the alarm that we
inspect. If so, the alarm is pending if "current time >= alarm
deadline", otherwise it is pending if "current time < alarm deadline".
Ref #2490
If the PIT timer driver gets activated too slow (e.g. because of a bad priority
configuration), it might miss counter wraps and would than produce sudden time
jumps. The driver now detects this problem dynamically, warns about it and
adapts the affected values to avoid time jumps.
Ref #2400
The NIC router always reports the link state "Up" (true) because
the effective link state depends on the targeted remote interface
and thus on the individual routing for each packet. Consequently,
also the signal handler for state changes gets ignored.
Ref #2490
IP stacks may treat a network interface as "down" when it states a MAC
address with the I/G bit (bit 40) set to "Group" (value 0) instead of
"Individual" (value 1). This was observed with a TinyCore 8 inside a
Virtualbox VM. Thus, the previously choosen 03:03:03:03:03:00 as base
for the MAC address allocator is bad. Now we use the 02:02:02:02:02:00
instead. This also ensures that the MAC addresses are not marked as
"Universal" but as "Local" (bit 41, value 1) which is correct in general
as the router allocates MAC addresses only for virtual networks.
Ref #2490
The NIC dump component didn't support forwarding of link states and link-state
signals until now. Furthermore, it now prints MAC address and link state
on session creation and on every link state change.
Ref #2490
Previously, the uplink session was created on component startup while the
creation of the downlink session is timed by the client component. This
created a time span in which packets from the uplink were dropped at the
nic_dump. Now the uplink session-request is done by the session component
of the downlink.
Ref #2490
