This avoids allocations for initializing the Function<T>
for the NetworkAdapter::for_each callback argument.
Applying this patch decreases CPU utilization for NetworkTask
from 40% to 28% when receiving TCP packets at a rate of 100Mbit/s.
We already have another limit for the total number of packet buffers
allowed (max_packet_buffers). This second limit caused us to
repeatedly allocate and then free buffers.
This matches what other operating systems like Linux do:
$ ip route get 0.0.0.0
local 0.0.0.0 dev lo src 127.0.0.1 uid 1000
cache <local>
$ ssh 0.0.0.0
gunnar@0.0.0.0's password:
$ ss -na | grep :22 | grep ESTAB
tcp ESTAB 0 0 127.0.0.1:43118 127.0.0.1:22
tcp ESTAB 0 0 127.0.0.1:22 127.0.0.1:43118
The last IP address in an IPv4 subnet is considered the directed
broadcast address, e.g. for 192.168.3.0/24 the directed broadcast
address is 192.168.3.255. We need to consider this address as
belonging to the interface.
Here's an example with this fix applied, SerenityOS has 192.168.3.190:
[gunnar@nyx ~]$ ping -b 192.168.3.255
WARNING: pinging broadcast address
PING 192.168.3.255 (192.168.3.255) 56(84) bytes of data.
64 bytes from 192.168.3.175: icmp_seq=1 ttl=64 time=0.950 ms
64 bytes from 192.168.3.188: icmp_seq=1 ttl=64 time=2.33 ms
64 bytes from 192.168.3.46: icmp_seq=1 ttl=64 time=2.77 ms
64 bytes from 192.168.3.41: icmp_seq=1 ttl=64 time=4.15 ms
64 bytes from 192.168.3.190: icmp_seq=1 ttl=64 time=29.4 ms
64 bytes from 192.168.3.42: icmp_seq=1 ttl=64 time=30.8 ms
64 bytes from 192.168.3.55: icmp_seq=1 ttl=64 time=31.0 ms
64 bytes from 192.168.3.30: icmp_seq=1 ttl=64 time=33.2 ms
64 bytes from 192.168.3.31: icmp_seq=1 ttl=64 time=33.2 ms
64 bytes from 192.168.3.173: icmp_seq=1 ttl=64 time=41.7 ms
64 bytes from 192.168.3.43: icmp_seq=1 ttl=64 time=47.7 ms
^C
--- 192.168.3.255 ping statistics ---
1 packets transmitted, 1 received, +10 duplicates, 0% packet loss,
time 0ms, rtt min/avg/max/mdev = 0.950/23.376/47.676/16.539 ms
[gunnar@nyx ~]$
SPDX License Identifiers are a more compact / standardized
way of representing file license information.
See: https://spdx.dev/resources/use/#identifiers
This was done with the `ambr` search and replace tool.
ambr --no-parent-ignore --key-from-file --rep-from-file key.txt rep.txt *
(...and ASSERT_NOT_REACHED => VERIFY_NOT_REACHED)
Since all of these checks are done in release builds as well,
let's rename them to VERIFY to prevent confusion, as everyone is
used to assertions being compiled out in release.
We can introduce a new ASSERT macro that is specifically for debug
checks, but I'm doing this wholesale conversion first since we've
accumulated thousands of these already, and it's not immediately
obvious which ones are suitable for ASSERT.
Since the receiving socket isn't yet known at packet receive time,
keep timestamps for all packets.
This is useful for keeping statistics about in-kernel queue latencies
in the future, and it can be used to implement SO_TIMESTAMP.
Since the CPU already does almost all necessary validation steps
for us, we don't really need to attempt to do this. Doing it
ourselves doesn't really work very reliably, because we'd have to
account for other processors modifying virtual memory, and we'd
have to account for e.g. pages not being able to be allocated
due to insufficient resources.
So change the copy_to/from_user (and associated helper functions)
to use the new safe_memcpy, which will return whether it succeeded
or not. The only manual validation step needed (which the CPU
can't perform for us) is making sure the pointers provided by user
mode aren't pointing to kernel mappings.
To make it easier to read/write from/to either kernel or user mode
data add the UserOrKernelBuffer helper class, which will internally
either use copy_from/to_user or directly memcpy, or pass the data
through directly using a temporary buffer on the stack.
Last but not least we need to keep syscall params trivial as we
need to copy them from/to user mode using copy_from/to_user.
MemoryManager cannot use the Singleton class because
MemoryManager::initialize is called before the global constructors
are run. That caused the Singleton to be re-initialized, causing
it to create another MemoryManager instance.
Fixes#3226
This was supposed to be the foundation for some kind of pre-kernel
environment, but nobody is working on it right now, so let's move
everything back into the kernel and remove all the confusion.
The idea behind WeakPtr<NetworkAdapter> was to support hot-pluggable
network adapters, but on closer thought, that's super impractical so
let's not go down that road.
As suggested by Joshua, this commit adds the 2-clause BSD license as a
comment block to the top of every source file.
For the first pass, I've just added myself for simplicity. I encourage
everyone to add themselves as copyright holders of any file they've
added or modified in some significant way. If I've added myself in
error somewhere, feel free to replace it with the appropriate copyright
holder instead.
Going forward, all new source files should include a license header.
The majority of the time in NetworkTask was being spent in allocating
and deallocating KBuffers for each incoming packet.
We'll now keep up to 100 buffers around and reuse them for new packets
if the next incoming packet fits in an old buffer. This is pretty
naively implemented but definitely cuts down on time spent here.
This defaults to 1500 for all adapters, but LoopbackAdapter increases
it to 65536 on construction.
If an IPv4 packet is larger than the MTU, we'll need to break it into
smaller fragments before transmitting it. This part is a FIXME. :^)
Made getsockopt() and setsockopt() virtual so we can handle them in the
various Socket subclasses. The subclasses map kinda nicely to "levels".
This will allow us to implement things like "traceroute", although..
I spent some time trying to do that, but then hit a wall when it turned
out that the user-mode networking in QEMU doesn't preserve TTL in the
ICMP packets passing through.
This is comprised of five small changes:
* Keep a counter for tx/rx packets/bytes per TCP socket
* Keep a counter for tx/rx packets/bytes per network adapter
* Expose that data in /proc/net_tcp and /proc/netadapters
* Convert /proc/netadapters to JSON
* Fix up ifconfig to read the JSON from netadapters
A KBuffer always contains a valid KBufferImpl. If you need a "null"
state buffer, use Optional<KBuffer>.
This makes KBuffer very easy to work with and pass around, just like
ByteBuffer before it.
There's no need for send_ipv4() to take a ByteBuffer&&, the data is
immediately cooked into a packet and transmitted. Instead, just pass
it the address+length of whatever buffer we've been using locally.
The more we can reduce the pressure on kmalloc the better. :^)
Replace the class-based snooze alarm mechanism with a per-thread callback.
This makes it easy to block the current thread on an arbitrary condition:
void SomeDevice::wait_for_irq() {
m_interrupted = false;
current->block_until([this] { return m_interrupted; });
}
void SomeDevice::handle_irq() {
m_interrupted = true;
}
Use this in the SB16 driver, and in NetworkTask :^)
