Method Bind

pkg/sentry/socket/netstack/netstack.go:855–914

Bind implements the linux syscall bind(2) for sockets backed by tcpip.Endpoint.

(_ *kernel.Task, sockaddr []byte)

// Bind implements the linux syscall bind(2) for sockets backed by
// tcpip.Endpoint.
func (s *sock) Bind(_ *kernel.Task, sockaddr []byte) *syserr.Error {
	if len(sockaddr) < 2 {
		return syserr.ErrInvalidArgument
	}

	family := hostarch.ByteOrder.Uint16(sockaddr)
	var addr tcpip.FullAddress

	// Bind for AF_PACKET requires only family, protocol and ifindex.
	// In function AddressAndFamily, we check the address length which is
	// not needed for AF_PACKET bind.
	if family == linux.AF_PACKET {
		var a linux.SockAddrLink
		if len(sockaddr) < linux.SockAddrLinkSize {
			return syserr.ErrInvalidArgument
		}
		a.UnmarshalBytes(sockaddr)

		addr = tcpip.FullAddress{
			NIC: tcpip.NICID(a.InterfaceIndex),
			Addr: tcpip.AddrFrom16Slice(append(
				a.HardwareAddr[:header.EthernetAddressSize],
				[]byte{0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00}...,
			)),
			Port: socket.Ntohs(a.Protocol),
		}
	} else {
		if s.minSockAddrLen() > len(sockaddr) {
			return syserr.ErrInvalidArgument
		}

		var err *syserr.Error
		addr, family, err = socket.AddressAndFamily(sockaddr)
		if err != nil {
			return err
		}

		if !s.checkFamily(family, true /* exact */) {
			return syserr.ErrAddressFamilyNotSupported
		}

		addr = s.mapFamily(addr, family)
	}

	// Issue the bind request to the endpoint.
	err := s.Endpoint.Bind(addr)
	if _, ok := err.(*tcpip.ErrNoPortAvailable); ok {
		// Bind always returns EADDRINUSE irrespective of if the specified port was
		// already bound or if an ephemeral port was requested but none were
		// available.
		//
		// *tcpip.ErrNoPortAvailable is mapped to EAGAIN in syserr package because
		// UDP connect returns EAGAIN on ephemeral port exhaustion.
		//
		// TCP connect returns EADDRNOTAVAIL on ephemeral port exhaustion.
		err = &tcpip.ErrPortInUse{}
	}