refactor(s2n-quic-platform): move pktinfo checks to separate modules

quic/s2n-quic-platform/src/features.rs

@@ -6,6 +6,11 @@ type c_int = std::os::raw::c_int;
 
 pub mod gro;
 pub mod gso;
+pub mod pktinfo;
+pub mod pktinfo_v4;
+pub mod pktinfo_v6;
+pub mod tos;
 pub mod tos_v4;
 pub mod tos_v6;
+
 pub use gso::Gso;

quic/s2n-quic-platform/src/features/pktinfo.rs

@@ -0,0 +1,4 @@
+// Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+// SPDX-License-Identifier: Apache-2.0
+
+pub const IS_SUPPORTED: bool = super::pktinfo_v4::IS_SUPPORTED || super::pktinfo_v6::IS_SUPPORTED;

quic/s2n-quic-platform/src/features/pktinfo_v4.rs

@@ -0,0 +1,105 @@
+// Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+// SPDX-License-Identifier: Apache-2.0
+
+use super::c_int;
+use s2n_quic_core::inet::IpV4Address;
+
+#[cfg(s2n_quic_platform_pktinfo)]
+mod pktinfo_enabled {
+    use super::*;
+    use crate::message::cmsg;
+    use libc::{IPPROTO_IP, IP_PKTINFO};
+
+    pub const LEVEL: Option<c_int> = Some(IPPROTO_IP as _);
+    pub const TYPE: Option<c_int> = Some(IP_PKTINFO as _);
+    pub const SOCKOPT: Option<(c_int, c_int)> = Some((IPPROTO_IP as _, IP_PKTINFO as _));
+    pub const CMSG_SPACE: usize = crate::message::cmsg::size_of_cmsg::<Cmsg>();
+
+    pub type Cmsg = libc::in_pktinfo;
+
+    #[inline]
+    pub const fn is_match(level: c_int, ty: c_int) -> bool {
+        level == IPPROTO_IP as c_int && ty == IP_PKTINFO as c_int
+    }
+
+    /// # Safety
+    ///
+    /// * The provided bytes must be aligned to `cmsghdr`
+    #[inline]
+    pub unsafe fn decode(bytes: &[u8]) -> Option<(IpV4Address, u32)> {
+        let pkt_info = cmsg::decode::value_from_bytes::<Cmsg>(bytes)?;
+
+        // read from both fields in case only one is set and not the other
+        //
+        // from https://man7.org/linux/man-pages/man7/ip.7.html:
+        //
+        // > ipi_spec_dst is the local address
+        // > of the packet and ipi_addr is the destination address in
+        // > the packet header.
+        let local_address = match (pkt_info.ipi_addr.s_addr, pkt_info.ipi_spec_dst.s_addr) {
+            (0, v) => v.to_ne_bytes(),
+            (v, _) => v.to_ne_bytes(),
+        };
+
+        let address = IpV4Address::new(local_address);
+        let interface = pkt_info.ipi_ifindex as _;
+
+        Some((address, interface))
+    }
+
+    #[inline]
+    pub fn encode(addr: &IpV4Address, local_interface: Option<u32>) -> Cmsg {
+        let mut pkt_info = unsafe { core::mem::zeroed::<Cmsg>() };
+        pkt_info.ipi_spec_dst.s_addr = u32::from_ne_bytes((*addr).into());
+        if let Some(interface) = local_interface {
+            pkt_info.ipi_ifindex = interface as _;
+        }
+        pkt_info
+    }
+}
+
+#[cfg(any(not(s2n_quic_platform_pktinfo), test))]
+mod pktinfo_disabled {
+    #![cfg_attr(test, allow(dead_code))]
+    use super::*;
+
+    pub const LEVEL: Option<c_int> = None;
+    pub const TYPE: Option<c_int> = None;
+    pub const SOCKOPT: Option<(c_int, c_int)> = None;
+    pub const CMSG_SPACE: usize = 0;
+
+    pub type Cmsg = c_int;
+
+    #[inline]
+    pub const fn is_match(level: c_int, ty: c_int) -> bool {
+        let _ = level;
+        let _ = ty;
+        false
+    }
+
+    /// # Safety
+    ///
+    /// * The provided bytes must be aligned to `cmsghdr`
+    pub unsafe fn decode(bytes: &[u8]) -> Option<(IpV4Address, u32)> {
+        let _ = bytes;
+        None
+    }
+
+    #[inline]
+    pub fn encode(addr: &IpV4Address, local_interface: Option<u32>) -> Cmsg {
+        let _ = addr;
+        let _ = local_interface;
+        unimplemented!("this platform does not support pktinfo")
+    }
+}
+
+mod pktinfo_impl {
+    #[cfg(not(s2n_quic_platform_pktinfo))]
+    pub use super::pktinfo_disabled::*;
+    #[cfg(s2n_quic_platform_pktinfo)]
+    pub use super::pktinfo_enabled::*;
+}
+
+pub use pktinfo_impl::*;
+
+pub const IS_SUPPORTED: bool = cfg!(s2n_quic_platform_pktinfo);

quic/s2n-quic-platform/src/features/pktinfo_v6.rs

@@ -0,0 +1,94 @@
+// Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+// SPDX-License-Identifier: Apache-2.0
+
+use super::c_int;
+use s2n_quic_core::inet::IpV6Address;
+
+#[cfg(s2n_quic_platform_pktinfo)]
+mod pktinfo_enabled {
+    use super::*;
+    use crate::message::cmsg;
+    use libc::{IPPROTO_IPV6, IPV6_PKTINFO, IPV6_RECVPKTINFO};
+
+    pub const LEVEL: Option<c_int> = Some(IPPROTO_IPV6 as _);
+    pub const TYPE: Option<c_int> = Some(IPV6_PKTINFO as _);
+    pub const SOCKOPT: Option<(c_int, c_int)> = Some((IPPROTO_IPV6 as _, IPV6_RECVPKTINFO));
+    pub const CMSG_SPACE: usize = crate::message::cmsg::size_of_cmsg::<Cmsg>();
+
+    pub type Cmsg = libc::in6_pktinfo;
+
+    #[inline]
+    pub const fn is_match(level: c_int, ty: c_int) -> bool {
+        level == IPPROTO_IPV6 as c_int && ty == IPV6_PKTINFO as c_int
+    }
+
+    /// # Safety
+    ///
+    /// * The provided bytes must be aligned to `cmsghdr`
+    pub unsafe fn decode(bytes: &[u8]) -> Option<(IpV6Address, u32)> {
+        let pkt_info = cmsg::decode::value_from_bytes::<Cmsg>(bytes)?;
+
+        let local_address = pkt_info.ipi6_addr.s6_addr;
+
+        let address = IpV6Address::new(local_address);
+        let interface = pkt_info.ipi6_ifindex as _;
+
+        Some((address, interface))
+    }
+
+    #[inline]
+    pub fn encode(addr: &IpV6Address, local_interface: Option<u32>) -> Cmsg {
+        let mut pkt_info = unsafe { core::mem::zeroed::<Cmsg>() };
+        pkt_info.ipi6_addr.s6_addr = (*addr).into();
+        if let Some(interface) = local_interface {
+            pkt_info.ipi6_ifindex = interface as _;
+        }
+        pkt_info
+    }
+}
+
+#[cfg(any(not(s2n_quic_platform_pktinfo), test))]
+mod pktinfo_disabled {
+    #![cfg_attr(test, allow(dead_code))]
+    use super::*;
+
+    pub const LEVEL: Option<c_int> = None;
+    pub const TYPE: Option<c_int> = None;
+    pub const SOCKOPT: Option<(c_int, c_int)> = None;
+    pub const CMSG_SPACE: usize = 0;
+
+    pub type Cmsg = c_int;
+
+    #[inline]
+    pub const fn is_match(level: c_int, ty: c_int) -> bool {
+        let _ = level;
+        let _ = ty;
+        false
+    }
+
+    /// # Safety
+    ///
+    /// * The provided bytes must be aligned to `cmsghdr`
+    pub unsafe fn decode(bytes: &[u8]) -> Option<(IpV6Address, u32)> {
+        let _ = bytes;
+        None
+    }
+
+    #[inline]
+    pub fn encode(addr: &IpV6Address, local_interface: Option<u32>) -> Cmsg {
+        let _ = addr;
+        let _ = local_interface;
+        unimplemented!("this platform does not support pktinfo")
+    }
+}
+
+mod pktinfo_impl {
+    #[cfg(not(s2n_quic_platform_pktinfo))]
+    pub use super::pktinfo_disabled::*;
+    #[cfg(s2n_quic_platform_pktinfo)]
+    pub use super::pktinfo_enabled::*;
+}
+
+pub use pktinfo_impl::*;
+
+pub const IS_SUPPORTED: bool = cfg!(s2n_quic_platform_pktinfo);

quic/s2n-quic-platform/src/features/tos.rs

@@ -0,0 +1,23 @@
+// Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+// SPDX-License-Identifier: Apache-2.0
+
+use super::c_int;
+use s2n_quic_core::inet::ExplicitCongestionNotification;
+
+pub const IS_SUPPORTED: bool = super::tos_v4::IS_SUPPORTED || super::tos_v6::IS_SUPPORTED;
+
+#[inline]
+pub const fn is_match(level: c_int, ty: c_int) -> bool {
+    super::tos_v4::is_match(level, ty) || super::tos_v6::is_match(level, ty)
+}
+
+#[inline]
+pub fn decode(bytes: &[u8]) -> Option<ExplicitCongestionNotification> {
+    let value = match bytes.len() {
+        1 => bytes[0],
+        4 => u32::from_ne_bytes(bytes.try_into().unwrap()) as u8,
+        _ => return None,
+    };
+
+    Some(ExplicitCongestionNotification::new(value))
+}