Source file src/pkg/net/internal/socktest/switch.go

     1	// Copyright 2015 The Go Authors. All rights reserved.
     2	// Use of this source code is governed by a BSD-style
     3	// license that can be found in the LICENSE file.
     4	
     5	// Package socktest provides utilities for socket testing.
     6	package socktest
     7	
     8	import (
     9		"fmt"
    10		"sync"
    11	)
    12	
    13	// A Switch represents a callpath point switch for socket system
    14	// calls.
    15	type Switch struct {
    16		once sync.Once
    17	
    18		fmu   sync.RWMutex
    19		fltab map[FilterType]Filter
    20	
    21		smu   sync.RWMutex
    22		sotab Sockets
    23		stats stats
    24	}
    25	
    26	func (sw *Switch) init() {
    27		sw.fltab = make(map[FilterType]Filter)
    28		sw.sotab = make(Sockets)
    29		sw.stats = make(stats)
    30	}
    31	
    32	// Stats returns a list of per-cookie socket statistics.
    33	func (sw *Switch) Stats() []Stat {
    34		var st []Stat
    35		sw.smu.RLock()
    36		for _, s := range sw.stats {
    37			ns := *s
    38			st = append(st, ns)
    39		}
    40		sw.smu.RUnlock()
    41		return st
    42	}
    43	
    44	// Sockets returns mappings of socket descriptor to socket status.
    45	func (sw *Switch) Sockets() Sockets {
    46		sw.smu.RLock()
    47		tab := make(Sockets, len(sw.sotab))
    48		for i, s := range sw.sotab {
    49			tab[i] = s
    50		}
    51		sw.smu.RUnlock()
    52		return tab
    53	}
    54	
    55	// A Cookie represents a 3-tuple of a socket; address family, socket
    56	// type and protocol number.
    57	type Cookie uint64
    58	
    59	// Family returns an address family.
    60	func (c Cookie) Family() int { return int(c >> 48) }
    61	
    62	// Type returns a socket type.
    63	func (c Cookie) Type() int { return int(c << 16 >> 32) }
    64	
    65	// Protocol returns a protocol number.
    66	func (c Cookie) Protocol() int { return int(c & 0xff) }
    67	
    68	func cookie(family, sotype, proto int) Cookie {
    69		return Cookie(family)<<48 | Cookie(sotype)&0xffffffff<<16 | Cookie(proto)&0xff
    70	}
    71	
    72	// A Status represents the status of a socket.
    73	type Status struct {
    74		Cookie    Cookie
    75		Err       error // error status of socket system call
    76		SocketErr error // error status of socket by SO_ERROR
    77	}
    78	
    79	func (so Status) String() string {
    80		return fmt.Sprintf("(%s, %s, %s): syscallerr=%v socketerr=%v", familyString(so.Cookie.Family()), typeString(so.Cookie.Type()), protocolString(so.Cookie.Protocol()), so.Err, so.SocketErr)
    81	}
    82	
    83	// A Stat represents a per-cookie socket statistics.
    84	type Stat struct {
    85		Family   int // address family
    86		Type     int // socket type
    87		Protocol int // protocol number
    88	
    89		Opened    uint64 // number of sockets opened
    90		Connected uint64 // number of sockets connected
    91		Listened  uint64 // number of sockets listened
    92		Accepted  uint64 // number of sockets accepted
    93		Closed    uint64 // number of sockets closed
    94	
    95		OpenFailed    uint64 // number of sockets open failed
    96		ConnectFailed uint64 // number of sockets connect failed
    97		ListenFailed  uint64 // number of sockets listen failed
    98		AcceptFailed  uint64 // number of sockets accept failed
    99		CloseFailed   uint64 // number of sockets close failed
   100	}
   101	
   102	func (st Stat) String() string {
   103		return fmt.Sprintf("(%s, %s, %s): opened=%d connected=%d listened=%d accepted=%d closed=%d openfailed=%d connectfailed=%d listenfailed=%d acceptfailed=%d closefailed=%d", familyString(st.Family), typeString(st.Type), protocolString(st.Protocol), st.Opened, st.Connected, st.Listened, st.Accepted, st.Closed, st.OpenFailed, st.ConnectFailed, st.ListenFailed, st.AcceptFailed, st.CloseFailed)
   104	}
   105	
   106	type stats map[Cookie]*Stat
   107	
   108	func (st stats) getLocked(c Cookie) *Stat {
   109		s, ok := st[c]
   110		if !ok {
   111			s = &Stat{Family: c.Family(), Type: c.Type(), Protocol: c.Protocol()}
   112			st[c] = s
   113		}
   114		return s
   115	}
   116	
   117	// A FilterType represents a filter type.
   118	type FilterType int
   119	
   120	const (
   121		FilterSocket        FilterType = iota // for Socket
   122		FilterConnect                         // for Connect or ConnectEx
   123		FilterListen                          // for Listen
   124		FilterAccept                          // for Accept, Accept4 or AcceptEx
   125		FilterGetsockoptInt                   // for GetsockoptInt
   126		FilterClose                           // for Close or Closesocket
   127	)
   128	
   129	// A Filter represents a socket system call filter.
   130	//
   131	// It will only be executed before a system call for a socket that has
   132	// an entry in internal table.
   133	// If the filter returns a non-nil error, the execution of system call
   134	// will be canceled and the system call function returns the non-nil
   135	// error.
   136	// It can return a non-nil AfterFilter for filtering after the
   137	// execution of the system call.
   138	type Filter func(*Status) (AfterFilter, error)
   139	
   140	func (f Filter) apply(st *Status) (AfterFilter, error) {
   141		if f == nil {
   142			return nil, nil
   143		}
   144		return f(st)
   145	}
   146	
   147	// An AfterFilter represents a socket system call filter after an
   148	// execution of a system call.
   149	//
   150	// It will only be executed after a system call for a socket that has
   151	// an entry in internal table.
   152	// If the filter returns a non-nil error, the system call function
   153	// returns the non-nil error.
   154	type AfterFilter func(*Status) error
   155	
   156	func (f AfterFilter) apply(st *Status) error {
   157		if f == nil {
   158			return nil
   159		}
   160		return f(st)
   161	}
   162	
   163	// Set deploys the socket system call filter f for the filter type t.
   164	func (sw *Switch) Set(t FilterType, f Filter) {
   165		sw.once.Do(sw.init)
   166		sw.fmu.Lock()
   167		sw.fltab[t] = f
   168		sw.fmu.Unlock()
   169	}
   170	

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