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 = 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