Inside Bitcoin

1#!/usr/bin/env python3
2# Copyright (c) 2014-present The Bitcoin Core developers
3# Distributed under the MIT software license, see the accompanying
4# file COPYING or http://www.opensource.org/licenses/mit-license.php.
5"""Linux, macOS, BSD and illumos network utilities.
6
7Roughly based on https://web.archive.org/web/20190424172231/http://voorloopnul.com/blog/a-python-netstat-in-less-than-100-lines-of-code/ by Ricardo Pascal
8"""
9
10import http.client
11import sys
12import socket
13import struct
14import array
15import os
16
17# Easily unreachable address. Attempts to connect to it will stay within the machine.
18# Used to avoid non-loopback traffic or DNS queries.
19UNREACHABLE_PROXY_ARG = '-proxy=127.0.0.1:1'
20
21# STATE_ESTABLISHED = '01'
22# STATE_SYN_SENT  = '02'
23# STATE_SYN_RECV = '03'
24# STATE_FIN_WAIT1 = '04'
25# STATE_FIN_WAIT2 = '05'
26# STATE_TIME_WAIT = '06'
27# STATE_CLOSE = '07'
28# STATE_CLOSE_WAIT = '08'
29# STATE_LAST_ACK = '09'
30STATE_LISTEN = '0A'
31# STATE_CLOSING = '0B'
32
33# Address manager size constants as defined in addrman_impl.h
34ADDRMAN_NEW_BUCKET_COUNT = 1 << 10
35ADDRMAN_TRIED_BUCKET_COUNT = 1 << 8
36ADDRMAN_BUCKET_SIZE = 1 << 6
37
38# When a test expects a server disconnection, any of these errors are
39# acceptable. The specific event is determined by race condition and platform OS.
40NETWORK_ERRORS = (
41    BrokenPipeError,                 # write to a closed socket/pipe
42    ConnectionResetError,            # connection forcibly closed by peer
43    ConnectionAbortedError,          # connection aborted locally or by network stack
44    http.client.ResponseNotReady,    # server response not ready or connection out of sync
45)
46
47def get_socket_inodes(pid):
48    '''
49    Get list of socket inodes for process pid.
50    '''
51    base = '/proc/%i/fd' % pid
52    inodes = []
53    for item in os.listdir(base):
54        try:
55            target = os.readlink(os.path.join(base, item))
56            if target.startswith('socket:'):
57                inodes.append(int(target[8:-1]))
58        except FileNotFoundError:
59            pass
60    return inodes
61
62def _remove_empty(array):
63    return [x for x in array if x !='']
64
65def _convert_ip_port(array):
66    host,port = array.split(':')
67    # convert host from mangled-per-four-bytes form as used by kernel
68    host = bytes.fromhex(host)
69    host_out = ''
70    for x in range(0, len(host) // 4):
71        (val,) = struct.unpack('=I', host[x*4:(x+1)*4])
72        host_out += '%08x' % val
73
74    return host_out,int(port,16)
75
76def netstat(typ='tcp'):
77    '''
78    Function to return a list with status of tcp connections at linux systems
79    To get pid of all network process running on system, you must run this script
80    as superuser
81    '''
82    with open('/proc/net/'+typ,'r') as f:
83        content = f.readlines()
84        content.pop(0)
85    result = []
86    for line in content:
87        line_array = _remove_empty(line.split(' '))     # Split lines and remove empty spaces.
88        tcp_id = line_array[0]
89        l_addr = _convert_ip_port(line_array[1])
90        r_addr = _convert_ip_port(line_array[2])
91        state = line_array[3]
92        inode = int(line_array[9])                      # Need the inode to match with process pid.
93        nline = [tcp_id, l_addr, r_addr, state, inode]
94        result.append(nline)
95    return result
96
97def get_bind_addrs(pid):
98    '''
99    Get bind addresses as (host,port) tuples for process pid.
100    '''
101    if sys.platform == 'linux':
102        inodes = get_socket_inodes(pid)
103        bind_addrs = []
104        for conn in netstat('tcp') + netstat('tcp6'):
105            if conn[3] == STATE_LISTEN and conn[4] in inodes:
106                bind_addrs.append(conn[1])
107        return bind_addrs
108    # OpenBSD is not included, as it does not ship the lsof utility.
109    elif sys.platform.startswith(("darwin", "freebsd", "netbsd", "sunos5")):
110        import re
111        import subprocess
112        output = subprocess.check_output(["lsof",
113            *(["-Di"] if sys.platform.startswith(("freebsd", "netbsd", "sunos5")) else []), # Ignore device cache to avoid stderr warnings.
114            *(["-w"] if sys.platform.startswith("netbsd") else []), # Ignore point release mismatch warnings.
115            "-nP",          # Keep hosts and ports numeric.
116            "-a",           # Require all filters to match.
117            "-p", str(pid), # Limit results to the target pid.
118            "-iTCP",        # Only inspect TCP sockets.
119            "-sTCP:LISTEN", # Only keep listening sockets.
120            "-Ftn",         # Emit machine-readable type and name fields.
121        ], text=True)
122        return [
123            (addr_to_hex(("::" if sock_type == "IPv6" else "0.0.0.0") if host == "*" else host.strip("[]")), int(port))
124            for sock_type, host, port in re.findall(r"t(IPv[46])\nn(\*|\[.+?]|[^:]+):(\d+)", output)
125        ]
126    else:
127        raise NotImplementedError(f"get_bind_addrs is not supported on {sys.platform}")
128
129def all_interfaces():
130    '''
131    Return all IPv4 interfaces that are up.
132    '''
133    if sys.platform == 'linux':
134        import fcntl  # Linux only, so only import when required
135
136        is_64bits = sys.maxsize > 2**32
137        struct_size = 40 if is_64bits else 32
138        s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
139        max_possible = 8 # initial value
140        while True:
141            bytes = max_possible * struct_size
142            names = array.array('B', b'\0' * bytes)
143            outbytes = struct.unpack('iL', fcntl.ioctl(
144                s.fileno(),
145                0x8912,  # SIOCGIFCONF
146                struct.pack('iL', bytes, names.buffer_info()[0])
147            ))[0]
148            if outbytes == bytes:
149                max_possible *= 2
150            else:
151                break
152        namestr = names.tobytes()
153        return [(namestr[i:i+16].split(b'\0', 1)[0],
154                 socket.inet_ntoa(namestr[i+20:i+24]))
155                for i in range(0, outbytes, struct_size)]
156    elif sys.platform.startswith(("darwin", "freebsd", "netbsd", "openbsd", "sunos5")):
157        import re
158        import subprocess
159        output = subprocess.check_output(["ifconfig", "-au"], text=True)
160        return [
161            (m["iface"].encode(), ip)
162            for m in re.finditer(r"(?m)^(?P<iface>\S+):(?P<block>[^\n]*(?:\n[ \t]+[^\n]*)*)", output)
163            for ip in re.findall(r"inet ([^\s/]+)", m["block"])
164        ]
165    else:
166        raise NotImplementedError(f"all_interfaces is not supported on {sys.platform}")
167
168def addr_to_hex(addr):
169    '''
170    Convert string IPv4 or IPv6 address to binary address as returned by
171    get_bind_addrs.
172    Very naive implementation that certainly doesn't work for all IPv6 variants.
173    '''
174    if '.' in addr: # IPv4
175        addr = [int(x) for x in addr.split('.')]
176    elif ':' in addr: # IPv6
177        sub = [[], []] # prefix, suffix
178        x = 0
179        addr = addr.split(':')
180        for i,comp in enumerate(addr):
181            if comp == '':
182                if i == 0 or i == (len(addr)-1): # skip empty component at beginning or end
183                    continue
184                x += 1 # :: skips to suffix
185                assert x < 2
186            else: # two bytes per component
187                val = int(comp, 16)
188                sub[x].append(val >> 8)
189                sub[x].append(val & 0xff)
190        nullbytes = 16 - len(sub[0]) - len(sub[1])
191        assert (x == 0 and nullbytes == 0) or (x == 1 and nullbytes > 0)
192        addr = sub[0] + ([0] * nullbytes) + sub[1]
193    else:
194        raise ValueError('Could not parse address %s' % addr)
195    return bytearray(addr).hex()
196
197def test_ipv6_local():
198    '''
199    Check for (local) IPv6 support.
200    '''
201    # By using SOCK_DGRAM this will not actually make a connection, but it will
202    # fail if there is no route to IPv6 localhost.
203    have_ipv6 = True
204    try:
205        s = socket.socket(socket.AF_INET6, socket.SOCK_DGRAM)
206        s.connect(('::1', 1))
207    except socket.error:
208        have_ipv6 = False
209    return have_ipv6
210
211def test_unix_socket():
212    '''Return True if UNIX sockets are available on this platform.'''
213    try:
214        socket.AF_UNIX
215    except AttributeError:
216        return False
217    else:
218        return True
219
220def format_addr_port(addr, port):
221    '''Return either "addr:port" or "[addr]:port" based on whether addr looks like an IPv6 address.'''
222    if ":" in addr:
223        return f"[{addr}]:{port}"
224    else:
225        return f"{addr}:{port}"
226
227def format_sock(sock, *, local):
228    '''
229    Format either local or remote side of a socket to a human readable string, e.g.
230    1.2.3.4:8333 or
231    [11:22::33]:8333 or
232    /path/to/socket or
233    @abstract-socket
234    '''
235    try:
236        if local:
237            name = sock.getsockname()
238        else:
239            name = sock.getpeername()
240    except Exception:
241        return "n/a"
242
243    if sock.family == socket.AF_INET:
244        return f"{name[0]}:{name[1]}"
245
246    if sock.family == socket.AF_INET6:
247        return f"[{name[0]}]:{name[1]}"
248
249    if sock.family == socket.AF_UNIX:
250        if isinstance(name, bytes):