Ping on MicroPython
最近做的MicroPython小项目，需要用到ping命令的功能，检查指定IP的电脑是否有开机并联网。
找了一圈，找到这个ping功能的源码。没有深究代码，就是能用。而且跟常用的ping命令差不多。
- Ping command | Pycom user forum
https://forum.pycom.io/topic/4930/ping-command/15
源码没改，直接搬过来，避免以后找不到：
# µPing (MicroPing) for MicroPython
# copyright (c) 2018 Shawwwn <shawwwn1@gmail.com>
# License: MIT
#
# Internet Checksum Algorithm
# Author: Olav Morken
# https://github.com/olavmrk/python-ping/blob/master/ping.py
# @data: bytes
#
# source code from: https://forum.pycom.io/topic/4930/ping-command/15
#
def checksum(data):
if len(data) & 0x1: # Odd number of bytes
data += b'\0'
cs = 0
for pos in range(0, len(data), 2):
b1 = data[pos]
b2 = data[pos + 1]
cs += (b1 << 8) + b2
while cs >= 0x10000:
cs = (cs & 0xffff) + (cs >> 16)
cs = ~cs & 0xffff
return cs
def ping(host, count=4, timeout=5000, interval=10, quiet=False, size=64):
import utime
import uselect
import uctypes
import usocket
import ustruct
import uos
# prepare packet
assert size >= 16, "pkt size too small"
pkt = b'Q'*size
pkt_desc = {
"type": uctypes.UINT8 | 0,
"code": uctypes.UINT8 | 1,
"checksum": uctypes.UINT16 | 2,
"id": (uctypes.ARRAY | 4, 2 | uctypes.UINT8),
"seq": uctypes.INT16 | 6,
"timestamp": uctypes.UINT64 | 8,
} # packet header descriptor
h = uctypes.struct(uctypes.addressof(pkt), pkt_desc, uctypes.BIG_ENDIAN)
h.type = 8 # ICMP_ECHO_REQUEST
h.code = 0
h.checksum = 0
h.id[0:2] = uos.urandom(2)
h.seq = 1
# init socket
sock = usocket.socket(usocket.AF_INET, usocket.SOCK_RAW, 1)
sock.setblocking(0)
sock.settimeout(timeout/1000)
try:
addr = usocket.getaddrinfo(host, 1)[0][-1][0] # ip address
except IndexError:
not quiet and print("Could not determine the address of", host)
return None
sock.connect((addr, 1))
not quiet and print("PING %s (%s): %u data bytes" % (host, addr, len(pkt)))
seqs = list(range(1, count+1)) # [1,2,...,count]
c = 1
t = 0
n_trans = 0
n_recv = 0
finish = False
while t < timeout:
if t==interval and c<=count:
# send packet
h.checksum = 0
h.seq = c
h.timestamp = utime.ticks_us()
h.checksum = checksum(pkt)
if sock.send(pkt) == size:
n_trans += 1
t = 0 # reset timeout
else:
seqs.remove(c)
c += 1
# recv packet
while 1:
socks, _, _ = uselect.select([sock], [], [], 0)
if socks:
resp = socks[0].recv(4096)
resp_mv = memoryview(resp)
h2 = uctypes.struct(uctypes.addressof(resp_mv[20:]), pkt_desc, uctypes.BIG_ENDIAN)
# TODO: validate checksum (optional)
seq = h2.seq
if h2.type==0 and h2.id==h.id and (seq in seqs): # 0: ICMP_ECHO_REPLY
t_elasped = (utime.ticks_us()-h2.timestamp) / 1000
ttl = ustruct.unpack('!B', resp_mv[8:9])[0] # time-to-live
n_recv += 1
not quiet and print("%u bytes from %s: icmp_seq=%u, ttl=%u, time=%f ms" % (len(resp), addr, seq, ttl, t_elasped))
seqs.remove(seq)
if len(seqs) == 0:
finish = True
break
else:
break
if finish:
break
utime.sleep_ms(1)
t += 1
# close
sock.close()
ret = (n_trans, n_recv)
not quiet and print("%u packets transmitted, %u packets received" % (n_trans, n_recv))
return (n_trans, n_recv)