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{
pov,
config,
lib,
...
}:
let
inherit (lib) types;
cfg = lib.getAttrFromPath pov config;
in
{
option = {
type = types.bool;
default = false;
};
config = lib.mkIf (cfg.enable && cfg.networking) {
boot.kernel.sysctl = {
# Enable strict reverse path filtering (that is, do not attempt to route
# packets that "obviously" do not belong to the iface's network; dropped
# packets are logged as martians).
"net.ipv4.conf.all.log_martians" = lib.mkDefault true;
"net.ipv4.conf.all.rp_filter" = lib.mkDefault "1";
"net.ipv4.conf.default.log_martians" = lib.mkDefault true;
"net.ipv4.conf.default.rp_filter" = lib.mkDefault "1";
# Ignore broadcast ICMP (mitigate SMURF)
"net.ipv4.icmp_echo_ignore_broadcasts" = lib.mkDefault true;
# Ignore incoming ICMP redirects (note: default is needed to ensure that the
# setting is applied to interfaces added after the sysctls are set)
"net.ipv4.conf.all.accept_redirects" = lib.mkDefault false;
"net.ipv4.conf.all.secure_redirects" = lib.mkDefault false;
"net.ipv4.conf.default.accept_redirects" = lib.mkDefault false;
"net.ipv4.conf.default.secure_redirects" = lib.mkDefault false;
"net.ipv6.conf.all.accept_redirects" = lib.mkDefault false;
"net.ipv6.conf.default.accept_redirects" = lib.mkDefault false;
# Ignore outgoing ICMP redirects (this is ipv4 only)
"net.ipv4.conf.all.send_redirects" = lib.mkDefault false;
"net.ipv4.conf.default.send_redirects" = lib.mkDefault false;
};
};
}