github.com/kubearmor/cilium@v1.6.12/proxylib/accesslog/client.go (about)

     1  // Copyright 2018 Authors of Cilium
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  package accesslog
    16  
    17  import (
    18  	"net"
    19  	"sync/atomic"
    20  	"unsafe"
    21  
    22  	"github.com/cilium/cilium/pkg/lock"
    23  	"github.com/cilium/cilium/proxylib/proxylib"
    24  
    25  	"github.com/cilium/proxy/go/cilium/api"
    26  	"github.com/golang/protobuf/proto"
    27  	log "github.com/sirupsen/logrus"
    28  )
    29  
    30  type Client struct {
    31  	connected uint32 // Accessed atomically without locking
    32  	path      string
    33  	mutex     lock.Mutex     // Used to protect opening the connection
    34  	conn      unsafe.Pointer // Read atomically without locking
    35  }
    36  
    37  func (cl *Client) connect() *net.UnixConn {
    38  	if cl.path == "" {
    39  		return nil
    40  	}
    41  
    42  	if atomic.LoadUint32(&cl.connected) > 0 {
    43  		// Guaranteed to be non-nil
    44  		return (*net.UnixConn)(atomic.LoadPointer(&cl.conn))
    45  	}
    46  
    47  	cl.mutex.Lock()
    48  	defer cl.mutex.Unlock()
    49  
    50  	// Safe to read cl.conn while holding the mutex
    51  	conn := (*net.UnixConn)(cl.conn)
    52  
    53  	// Did someone else connect while we were contending on the lock?
    54  	// cl.connected may be written to by others concurrently
    55  	if atomic.LoadUint32(&cl.connected) > 0 {
    56  		return conn
    57  	}
    58  
    59  	if conn != nil {
    60  		conn.Close() // not setting conn to nil!
    61  	}
    62  	log.Debugf("Accesslog: Connecting to Cilium access log socket: %s", cl.path)
    63  	conn, err := net.DialUnix("unixpacket", nil, &net.UnixAddr{Name: cl.path, Net: "unixpacket"})
    64  	if err != nil {
    65  		log.Errorf("Accesslog: DialUnix() failed: %v", err)
    66  		return nil
    67  	}
    68  
    69  	atomic.StorePointer(&cl.conn, unsafe.Pointer(conn))
    70  
    71  	// Always have a non-nil 'cl.conn' after 'cl.connected' is set for the first time!
    72  	atomic.StoreUint32(&cl.connected, 1)
    73  	return conn
    74  }
    75  
    76  func (cl *Client) Log(pblog *cilium.LogEntry) {
    77  	if conn := cl.connect(); conn != nil {
    78  		// Encode
    79  		logmsg, err := proto.Marshal(pblog)
    80  		if err != nil {
    81  			log.Errorf("Accesslog: Protobuf marshaling error: %v", err)
    82  			return
    83  		}
    84  
    85  		// Write
    86  		_, err = conn.Write(logmsg)
    87  		if err != nil {
    88  			log.Errorf("Accesslog: Write() failed: %v", err)
    89  			atomic.StoreUint32(&cl.connected, 0) // Mark connection as broken
    90  		}
    91  	} else {
    92  		log.Debugf("Accesslog: No connection, cannot send: %s", pblog.String())
    93  	}
    94  }
    95  
    96  func (c *Client) Path() string {
    97  	return c.path
    98  }
    99  
   100  func NewClient(accessLogPath string) proxylib.AccessLogger {
   101  	client := &Client{
   102  		path: accessLogPath,
   103  	}
   104  	client.connect()
   105  	return client
   106  }
   107  
   108  func (cl *Client) Close() {
   109  	conn := (*net.UnixConn)(atomic.LoadPointer(&cl.conn))
   110  	if conn != nil {
   111  		conn.Close()
   112  	}
   113  }