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use std::ffi::CString;
use std::net::IpAddr;
use ipnetwork::IpNetwork;
use crate::data_type::ip_to_vec;
use crate::error::BuilderError;
use crate::expr::ct::{ConnTrackState, Conntrack, ConntrackKey};
use crate::expr::{
Bitwise, Cmp, CmpOp, HighLevelPayload, IPv4HeaderField, IPv6HeaderField, Immediate, Masquerade,
Meta, MetaType, Nat, NatType, NetworkHeaderField, Register, TCPHeaderField,
TransportHeaderField, UDPHeaderField, VerdictKind,
};
use crate::{ProtocolFamily, Rule};
/// Simple protocol description. Note that it does not implement other layer 4 protocols as
/// IGMP et al. See [`Rule::igmp`] for a workaround.
#[derive(Debug, Copy, Clone, PartialEq, Eq)]
pub enum Protocol {
TCP,
UDP,
}
impl Rule {
fn match_port(mut self, port: u16, protocol: Protocol, source: bool) -> Self {
self = self.protocol(protocol);
self.add_expr(
HighLevelPayload::Transport(match protocol {
Protocol::TCP => TransportHeaderField::Tcp(if source {
TCPHeaderField::Sport
} else {
TCPHeaderField::Dport
}),
Protocol::UDP => TransportHeaderField::Udp(if source {
UDPHeaderField::Sport
} else {
UDPHeaderField::Dport
}),
})
.build(),
);
self.add_expr(Cmp::new(CmpOp::Eq, port.to_be_bytes()));
self
}
pub fn match_ip(mut self, ip: IpAddr, source: bool) -> Self {
self.add_expr(Meta::new(MetaType::NfProto));
match ip {
IpAddr::V4(addr) => {
self.add_expr(Cmp::new(CmpOp::Eq, [libc::NFPROTO_IPV4 as u8]));
self.add_expr(
HighLevelPayload::Network(NetworkHeaderField::IPv4(if source {
IPv4HeaderField::Saddr
} else {
IPv4HeaderField::Daddr
}))
.build(),
);
self.add_expr(Cmp::new(CmpOp::Eq, addr.octets()));
}
IpAddr::V6(addr) => {
self.add_expr(Cmp::new(CmpOp::Eq, [libc::NFPROTO_IPV6 as u8]));
self.add_expr(
HighLevelPayload::Network(NetworkHeaderField::IPv6(if source {
IPv6HeaderField::Saddr
} else {
IPv6HeaderField::Daddr
}))
.build(),
);
self.add_expr(Cmp::new(CmpOp::Eq, addr.octets()));
}
}
self
}
pub fn match_network(mut self, net: IpNetwork, source: bool) -> Result<Self, BuilderError> {
self.add_expr(Meta::new(MetaType::NfProto));
match net {
IpNetwork::V4(_) => {
self.add_expr(Cmp::new(CmpOp::Eq, [libc::NFPROTO_IPV4 as u8]));
self.add_expr(
HighLevelPayload::Network(NetworkHeaderField::IPv4(if source {
IPv4HeaderField::Saddr
} else {
IPv4HeaderField::Daddr
}))
.build(),
);
self.add_expr(Bitwise::new(ip_to_vec(net.mask()), 0u32.to_be_bytes())?);
}
IpNetwork::V6(_) => {
self.add_expr(Cmp::new(CmpOp::Eq, [libc::NFPROTO_IPV6 as u8]));
self.add_expr(
HighLevelPayload::Network(NetworkHeaderField::IPv6(if source {
IPv6HeaderField::Saddr
} else {
IPv6HeaderField::Daddr
}))
.build(),
);
self.add_expr(Bitwise::new(ip_to_vec(net.mask()), 0u128.to_be_bytes())?);
}
}
self.add_expr(Cmp::new(CmpOp::Eq, ip_to_vec(net.network())));
Ok(self)
}
}
impl Rule {
/// Matches ICMP packets.
pub fn icmp(mut self) -> Self {
self.add_expr(Meta::new(MetaType::L4Proto));
self.add_expr(Cmp::new(CmpOp::Eq, [libc::IPPROTO_ICMP as u8]));
self
}
/// Matches ICMPv6 packets.
pub fn icmpv6(mut self) -> Self {
self.add_expr(Meta::new(MetaType::L4Proto));
self.add_expr(Cmp::new(CmpOp::Eq, [libc::IPPROTO_ICMPV6 as u8]));
self
}
/// Matches IGMP packets.
pub fn igmp(mut self) -> Self {
self.add_expr(Meta::new(MetaType::L4Proto));
self.add_expr(Cmp::new(CmpOp::Eq, [libc::IPPROTO_IGMP as u8]));
self
}
/// Matches packets from source `port` and `protocol`.
pub fn sport(self, port: u16, protocol: Protocol) -> Self {
self.match_port(port, protocol, false)
}
/// Matches packets to destination `port` and `protocol`.
pub fn dport(self, port: u16, protocol: Protocol) -> Self {
self.match_port(port, protocol, false)
}
/// Matches packets on `protocol`.
pub fn protocol(mut self, protocol: Protocol) -> Self {
self.add_expr(Meta::new(MetaType::L4Proto));
self.add_expr(Cmp::new(
CmpOp::Eq,
[match protocol {
Protocol::TCP => libc::IPPROTO_TCP,
Protocol::UDP => libc::IPPROTO_UDP,
} as u8],
));
self
}
/// Matches packets in an already established connection.
pub fn established(mut self) -> Result<Self, BuilderError> {
let allowed_states = ConnTrackState::ESTABLISHED.bits();
self.add_expr(Conntrack::new(ConntrackKey::State));
self.add_expr(Bitwise::new(
allowed_states.to_le_bytes(),
0u32.to_be_bytes(),
)?);
self.add_expr(Cmp::new(CmpOp::Neq, 0u32.to_be_bytes()));
Ok(self)
}
/// Matches packets going through `iface_index`. Interface indexes can be queried with
/// `iface_index()`.
pub fn iface_id(mut self, iface_index: libc::c_uint) -> Self {
self.add_expr(Meta::new(MetaType::Iif));
self.add_expr(Cmp::new(CmpOp::Eq, iface_index.to_be_bytes()));
self
}
/// Matches packets going through `iface_name`, an interface name, as in "wlan0" or "lo"
pub fn iface(mut self, iface_name: &str) -> Result<Self, BuilderError> {
if iface_name.len() >= libc::IFNAMSIZ {
return Err(BuilderError::InterfaceNameTooLong);
}
let mut iface_vec = iface_name.as_bytes().to_vec();
// null terminator
iface_vec.push(0u8);
self.add_expr(Meta::new(MetaType::IifName));
self.add_expr(Cmp::new(CmpOp::Eq, iface_vec));
Ok(self)
}
/// Matches packets leaving through `oface_index`. Interface indexes can be queried with
/// `iface_index()`.
pub fn oface_id(mut self, oface_index: libc::c_uint) -> Self {
self.add_expr(Meta::new(MetaType::Oif));
self.add_expr(Cmp::new(CmpOp::Eq, oface_index.to_be_bytes()));
self
}
/// Matches packets leaving through `oface_name`, an interface name, as in "wlan0" or "lo"
pub fn oface(mut self, oface_name: &str) -> Result<Self, BuilderError> {
if oface_name.len() >= libc::IFNAMSIZ {
return Err(BuilderError::InterfaceNameTooLong);
}
let mut oface_vec = oface_name.as_bytes().to_vec();
// null terminator
oface_vec.push(0u8);
self.add_expr(Meta::new(MetaType::OifName));
self.add_expr(Cmp::new(CmpOp::Eq, oface_vec));
Ok(self)
}
/// Matches packets whose source IP address is `saddr`.
pub fn saddr(self, ip: IpAddr) -> Self {
self.match_ip(ip, true)
}
/// Matches packets whose destination IP address is `saddr`.
pub fn daddr(self, ip: IpAddr) -> Self {
self.match_ip(ip, false)
}
/// Matches packets whose source network is `net`.
pub fn snetwork(self, net: IpNetwork) -> Result<Self, BuilderError> {
self.match_network(net, true)
}
/// Matches packets whose destination network is `net`.
pub fn dnetwork(self, net: IpNetwork) -> Result<Self, BuilderError> {
self.match_network(net, false)
}
/// Adds the `Accept` verdict to the rule. The packet will be sent to destination.
pub fn accept(mut self) -> Self {
self.add_expr(Immediate::new_verdict(VerdictKind::Accept));
self
}
/// Adds the `Drop` verdict to the rule. The packet will be dropped.
pub fn drop(mut self) -> Self {
self.add_expr(Immediate::new_verdict(VerdictKind::Drop));
self
}
/// Adds the `Masquerade` verdict to the rule. The packet will have its
/// source address rewritten.
pub fn masquerade(mut self) -> Self {
self.add_expr(Masquerade {});
self
}
/// Adds the `Nat` verdict to the rule, with type `DNat`. The packet
/// will have its destination address and optionally port rewritten.
pub fn dnat(mut self, dst: IpAddr, port: Option<u16>) -> Self {
self.add_expr(Immediate::new_data(ip_to_vec(dst), Register::Reg1));
if let Some(port) = port {
self.add_expr(Immediate::new_data(
port.to_be_bytes().to_vec(),
Register::Reg2,
));
}
self.add_expr(Nat {
nat_type: Some(NatType::DNat),
family: Some(ProtocolFamily::Ipv4),
ip_register: Some(Register::Reg1),
port_register: port.map(|_| Register::Reg2),
});
self
}
}
/// Looks up the interface index for a given interface name.
pub fn iface_index(name: &str) -> Result<libc::c_uint, std::io::Error> {
let c_name = CString::new(name)?;
let index = unsafe { libc::if_nametoindex(c_name.as_ptr()) };
match index {
0 => Err(std::io::Error::last_os_error()),
_ => Ok(index),
}
}
|
