syscall_linux.go

Documentation: google.golang.org/grpc/internal/channelz

     1  /*
     2   *
     3   * Copyright 2018 gRPC authors.
     4   *
     5   * Licensed under the Apache License, Version 2.0 (the "License");
     6   * you may not use this file except in compliance with the License.
     7   * You may obtain a copy of the License at
     8   *
     9   *     http://www.apache.org/licenses/LICENSE-2.0
    10   *
    11   * Unless required by applicable law or agreed to in writing, software
    12   * distributed under the License is distributed on an "AS IS" BASIS,
    13   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    14   * See the License for the specific language governing permissions and
    15   * limitations under the License.
    16   *
    17   */
    18  
    19  package channelz
    20  
    21  import (
    22  	"syscall"
    23  
    24  	"golang.org/x/sys/unix"
    25  )
    26  
    27  // SocketOptionData defines the struct to hold socket option data, and related
    28  // getter function to obtain info from fd.
    29  type SocketOptionData struct {
    30  	Linger      *unix.Linger
    31  	RecvTimeout *unix.Timeval
    32  	SendTimeout *unix.Timeval
    33  	TCPInfo     *unix.TCPInfo
    34  }
    35  
    36  // Getsockopt defines the function to get socket options requested by channelz.
    37  // It is to be passed to syscall.RawConn.Control().
    38  func (s *SocketOptionData) Getsockopt(fd uintptr) {
    39  	if v, err := unix.GetsockoptLinger(int(fd), syscall.SOL_SOCKET, syscall.SO_LINGER); err == nil {
    40  		s.Linger = v
    41  	}
    42  	if v, err := unix.GetsockoptTimeval(int(fd), syscall.SOL_SOCKET, syscall.SO_RCVTIMEO); err == nil {
    43  		s.RecvTimeout = v
    44  	}
    45  	if v, err := unix.GetsockoptTimeval(int(fd), syscall.SOL_SOCKET, syscall.SO_SNDTIMEO); err == nil {
    46  		s.SendTimeout = v
    47  	}
    48  	if v, err := unix.GetsockoptTCPInfo(int(fd), syscall.SOL_TCP, syscall.TCP_INFO); err == nil {
    49  		s.TCPInfo = v
    50  	}
    51  }
    52  
    53  // GetSocketOption gets the socket option info of the conn.
    54  func GetSocketOption(socket any) *SocketOptionData {
    55  	c, ok := socket.(syscall.Conn)
    56  	if !ok {
    57  		return nil
    58  	}
    59  	data := &SocketOptionData{}
    60  	if rawConn, err := c.SyscallConn(); err == nil {
    61  		rawConn.Control(data.Getsockopt)
    62  		return data
    63  	}
    64  	return nil
    65  }
    66
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