uquic/sys_conn_helper_linux.go

//go:build linux

package quic

import (
	"encoding/binary"
	"net/netip"
	"syscall"

	"golang.org/x/sys/unix"
)

const (
	msgTypeIPTOS = unix.IP_TOS
	ipv4PKTINFO  = unix.IP_PKTINFO
)

const batchSize = 8 // needs to smaller than MaxUint8 (otherwise the type of oobConn.readPos has to be changed)

func forceSetReceiveBuffer(c syscall.RawConn, bytes int) error {
	var serr error
	if err := c.Control(func(fd uintptr) {
		serr = unix.SetsockoptInt(int(fd), unix.SOL_SOCKET, unix.SO_RCVBUFFORCE, bytes)
	}); err != nil {
		return err
	}
	return serr
}

func forceSetSendBuffer(c syscall.RawConn, bytes int) error {
	var serr error
	if err := c.Control(func(fd uintptr) {
		serr = unix.SetsockoptInt(int(fd), unix.SOL_SOCKET, unix.SO_SNDBUFFORCE, bytes)
	}); err != nil {
		return err
	}
	return serr
}

func parseIPv4PktInfo(body []byte) (ip netip.Addr, ifIndex uint32, ok bool) {
	// struct in_pktinfo {
	// 	unsigned int   ipi_ifindex;  /* Interface index */
	// 	struct in_addr ipi_spec_dst; /* Local address */
	// 	struct in_addr ipi_addr;     /* Header Destination address */
	// };
	if len(body) != 12 {
		return netip.Addr{}, 0, false
	}
	return netip.AddrFrom4(*(*[4]byte)(body[8:12])), binary.LittleEndian.Uint32(body), true
}