Kernel: Respond to packets sent to the directed broadcast address

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 ~]$
This commit is contained in:
Gunnar Beutner 2021-04-26 15:38:26 +02:00 committed by Andreas Kling
parent ba9a285d56
commit a85d111cd1
Notes: sideshowbarker 2024-07-18 19:04:20 +09:00
2 changed files with 2 additions and 1 deletions

View file

@ -37,7 +37,7 @@ RefPtr<NetworkAdapter> NetworkAdapter::from_ipv4_address(const IPv4Address& addr
{ {
Locker locker(all_adapters().lock()); Locker locker(all_adapters().lock());
for (auto* adapter : all_adapters().resource()) { for (auto* adapter : all_adapters().resource()) {
if (adapter->ipv4_address() == address) if (adapter->ipv4_address() == address || adapter->ipv4_broadcast() == address)
return adapter; return adapter;
} }
if (address[0] == 127) if (address[0] == 127)

View file

@ -36,6 +36,7 @@ public:
MACAddress mac_address() { return m_mac_address; } MACAddress mac_address() { return m_mac_address; }
IPv4Address ipv4_address() const { return m_ipv4_address; } IPv4Address ipv4_address() const { return m_ipv4_address; }
IPv4Address ipv4_netmask() const { return m_ipv4_netmask; } IPv4Address ipv4_netmask() const { return m_ipv4_netmask; }
IPv4Address ipv4_broadcast() const { return IPv4Address { (m_ipv4_address.to_u32() & m_ipv4_netmask.to_u32()) | ~m_ipv4_netmask.to_u32() }; }
IPv4Address ipv4_gateway() const { return m_ipv4_gateway; } IPv4Address ipv4_gateway() const { return m_ipv4_gateway; }
virtual bool link_up() { return false; } virtual bool link_up() { return false; }