9 socket_wrapper - A library passing all socket communications through unix sockets.
14 LD_PRELOAD=libsocket_wrapper.so SOCKET_WRAPPER_DIR=/tmp/tmp.bQRELqDrhM SOCKET_WRAPPER_DEFAULT_IFACE=10 *./myapplication*
19 socket_wrapper aims to help client/server software development teams willing to
20 gain full functional test coverage. It makes possible to run several instances
21 of the full software stack on the same machine and perform locally functional
22 testing of complex network configurations.
24 - Redirects all network communication to happen over Unix sockets.
25 - Support for IPv4 and IPv6 socket and addressing emulation.
26 - Ability to capture network traffic in pcap format.
31 *SOCKET_WRAPPER_DIR*::
33 The user defines a directory where to put all the unix sockets using the
34 environment variable "SOCKET_WRAPPER_DIR=/path/to/socket_dir". When a server
35 opens a port or a client wants to connect, socket_wrapper will translate IP
36 addresses to a special socket_wrapper name and look for the relevant Unix
37 socket in the SOCKET_WRAPPER_DIR.
39 *SOCKET_WRAPPER_DEFAULT_IFACE*::
41 Additionally, the default interface to be used by an application is defined
42 with "SOCKET_WRAPPER_DEFAULT_IFACE=<ID>" where <ID> is between 2 and 254. This
43 is analogous to use the IPv4 addresses "127.0.0.<ID>" or IPv6 addresses
44 "fd00::5357:5f<IDx>" (where <IDx> is a hexadecimal presentation of <ID>). You
45 should always set the default interface. If you listen on INADDR_ANY then it
46 will use the default interface to listen on.
48 *SOCKET_WRAPPER_PCAP_FILE*::
50 When debugging, it is often interesting to investigate the network traffic
51 between the client and server within your application. If you define
52 SOCKET_WRAPPER_PCAP_FILE=/path/to/file.pcap, socket_wrapper will dump all your
53 network traffic to the specified file. After the test has been finished you're
54 able to open the file for example with Wireshark.
56 *SOCKET_WRAPPER_MTU*::
58 With this variable you can change the MTU size. However we do not recomment to
59 do that as the default size of 1500 byte is best for formatting PCAP files.
61 The minimum value you can set is 512 and the maximum 32768.
63 *SOCKET_WRAPPER_MAX_SOCKETS*::
65 This variable can be used to set the maximum number of sockets to be used by
68 The default value is set to 65535 and the maximum 256000.
70 *SOCKET_WRAPPER_DEBUGLEVEL*::
72 If you need to see what is going on in socket_wrapper itself or try to find a
73 bug, you can enable logging support in socket_wrapper if you built it with
81 *SOCKET_WRAPPER_DISABLE_DEEPBIND*::
83 This allows you to disable deep binding in socket_wrapper. This is useful for
84 running valgrind tools or sanitizers like (address, undefined, thread).
89 # Open a console and create a directory for the unix sockets.
93 # Then start nc to listen for network traffic using the temporary directory.
94 $ LD_PRELOAD=libsocket_wrapper.so \
95 SOCKET_WRAPPER_DIR=/tmp/tmp.bQRELqDrhM \
96 SOCKET_WRAPPER_DEFAULT_IFACE=10 nc -v -l 127.0.0.10 7
98 # (If nc, listens on 0.0.0.0 then listener will be open on 127.0.0.10 because
99 # it is the default interface)
101 # Now open another console and start 'nc' as a client to connect to the server:
102 $ LD_PRELOAD=libsocket_wrapper.so \
103 SOCKET_WRAPPER_DIR=/tmp/tmp.bQRELqDrhM \
104 SOCKET_WRAPPER_DEFAULT_IFACE=100 nc -v 127.0.0.10 7
106 # (The client will use the address 127.0.0.100 when connecting to the server)
107 # Now you can type 'Hello!' which will be sent to the server and should appear
108 # in the console output of the server.