Detect why a socket closed: FIN vs RST
2
Is it possible to detect why a socket closed in Python, i.e. whether the other side sent a FIN or an RST?
The only way I know to detect if the other side has senta FIN or RST, is to read from the socket, and if you get the empty (byte) string, then we have received either a FIN or an RST. But how to know which one?
import asyncio
import socket
async def async_main(loop):
server_sock = socket.socket(family=socket.AF_INET, type=socket.SOCK_STREAM,
proto=socket.IPPROTO_TCP)
server_sock.setblocking(False)
server_sock.bind(('', 8080))
server_sock.listen(socket.IPPROTO_TCP)
loop = asyncio.get_event_loop()
sock, adddress = await loop.sock_accept(server_sock)
while True:
data = await loop.sock_recv(sock, 1024)
if data == b'':
# Socket closed, but how?
break
print(data)
loop = asyncio.get_event_loop()
loop.run_until_complete(async_main(loop))
python python-3.x sockets tcp python-asyncio
asked Nov 16 '18 at 20:56
Michal CharemzaMichal Charemza
20k972106
add a comment |
2
Is it possible to detect why a socket closed in Python, i.e. whether the other side sent a FIN or an RST?
The only way I know to detect if the other side has senta FIN or RST, is to read from the socket, and if you get the empty (byte) string, then we have received either a FIN or an RST. But how to know which one?
import asyncio
import socket
async def async_main(loop):
server_sock = socket.socket(family=socket.AF_INET, type=socket.SOCK_STREAM,
proto=socket.IPPROTO_TCP)
server_sock.setblocking(False)
server_sock.bind(('', 8080))
server_sock.listen(socket.IPPROTO_TCP)
loop = asyncio.get_event_loop()
sock, adddress = await loop.sock_accept(server_sock)
while True:
data = await loop.sock_recv(sock, 1024)
if data == b'':
# Socket closed, but how?
break
print(data)
loop = asyncio.get_event_loop()
loop.run_until_complete(async_main(loop))
python python-3.x sockets tcp python-asyncio
asked Nov 16 '18 at 20:56
Michal CharemzaMichal Charemza
20k972106
2
I would expect an normal EOF condition(data == b'') only when receiving a FIN. If you receive a RST I'd expect an exception to be raised of the form "Connection reset by peer".
– James K Polk
Nov 17 '18 at 4:30
add a comment |
2
2
2
Is it possible to detect why a socket closed in Python, i.e. whether the other side sent a FIN or an RST?
The only way I know to detect if the other side has senta FIN or RST, is to read from the socket, and if you get the empty (byte) string, then we have received either a FIN or an RST. But how to know which one?
import asyncio
import socket
async def async_main(loop):
server_sock = socket.socket(family=socket.AF_INET, type=socket.SOCK_STREAM,
proto=socket.IPPROTO_TCP)
server_sock.setblocking(False)
server_sock.bind(('', 8080))
server_sock.listen(socket.IPPROTO_TCP)
loop = asyncio.get_event_loop()
sock, adddress = await loop.sock_accept(server_sock)
while True:
data = await loop.sock_recv(sock, 1024)
if data == b'':
# Socket closed, but how?
break
print(data)
loop = asyncio.get_event_loop()
loop.run_until_complete(async_main(loop))
python python-3.x sockets tcp python-asyncio
asked Nov 16 '18 at 20:56
Michal CharemzaMichal Charemza
20k972106
Is it possible to detect why a socket closed in Python, i.e. whether the other side sent a FIN or an RST?
The only way I know to detect if the other side has senta FIN or RST, is to read from the socket, and if you get the empty (byte) string, then we have received either a FIN or an RST. But how to know which one?
import asyncio
import socket
async def async_main(loop):
server_sock = socket.socket(family=socket.AF_INET, type=socket.SOCK_STREAM,
proto=socket.IPPROTO_TCP)
server_sock.setblocking(False)
server_sock.bind(('', 8080))
server_sock.listen(socket.IPPROTO_TCP)
loop = asyncio.get_event_loop()
sock, adddress = await loop.sock_accept(server_sock)
while True:
data = await loop.sock_recv(sock, 1024)
if data == b'':
# Socket closed, but how?
break
print(data)
loop = asyncio.get_event_loop()
loop.run_until_complete(async_main(loop))
python python-3.x sockets tcp python-asyncio
python python-3.x sockets tcp python-asyncio
asked Nov 16 '18 at 20:56
Michal CharemzaMichal Charemza
20k972106
asked Nov 16 '18 at 20:56
Michal CharemzaMichal Charemza
20k972106
asked Nov 16 '18 at 20:56
Michal CharemzaMichal Charemza
20k972106
asked Nov 16 '18 at 20:56
Michal CharemzaMichal Charemza
20k972106
asked Nov 16 '18 at 20:56
Michal CharemzaMichal Charemza
20k972106
20k972106
2
I would expect an normal EOF condition(data == b'') only when receiving a FIN. If you receive a RST I'd expect an exception to be raised of the form "Connection reset by peer".
– James K Polk
Nov 17 '18 at 4:30
add a comment |
2
I would expect an normal EOF condition(data == b'') only when receiving a FIN. If you receive a RST I'd expect an exception to be raised of the form "Connection reset by peer".
– James K Polk
Nov 17 '18 at 4:30
2
2
I would expect an normal EOF condition(data == b'') only when receiving a FIN. If you receive a RST I'd expect an exception to be raised of the form "Connection reset by peer".
– James K Polk
Nov 17 '18 at 4:30
I would expect an normal EOF condition(data == b'') only when receiving a FIN. If you receive a RST I'd expect an exception to be raised of the form "Connection reset by peer".
– James K Polk
Nov 17 '18 at 4:30
add a comment |
1 Answer
1
active
oldest
votes
2
Based on James K Polk's comment, which I believe to be correct, you would distinguish FIN from RST by catching the appropriate exception:
while True:
is_rst = False
try:
data = await loop.sock_recv(sock, 1024)
except IOError as e:
if e.errno == errno.ECONNRESET:
data = b''
is_rst = True
else:
raise
if data == b'':
# Connection closed - use is_rst to distinguish
# between RST and FIN
break
print(data)
answered Nov 17 '18 at 7:55
user4815162342user4815162342
61.8k592145
Ah thanks, and thanks to @james-k-polk : I was completely wrong in my assumptions.
– Michal Charemza
Nov 17 '18 at 8:22
add a comment |
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1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
2
Based on James K Polk's comment, which I believe to be correct, you would distinguish FIN from RST by catching the appropriate exception:
while True:
is_rst = False
try:
data = await loop.sock_recv(sock, 1024)
except IOError as e:
if e.errno == errno.ECONNRESET:
data = b''
is_rst = True
else:
raise
if data == b'':
# Connection closed - use is_rst to distinguish
# between RST and FIN
break
print(data)
answered Nov 17 '18 at 7:55
user4815162342user4815162342
61.8k592145
Ah thanks, and thanks to @james-k-polk : I was completely wrong in my assumptions.
– Michal Charemza
Nov 17 '18 at 8:22
add a comment |
2
Based on James K Polk's comment, which I believe to be correct, you would distinguish FIN from RST by catching the appropriate exception:
while True:
is_rst = False
try:
data = await loop.sock_recv(sock, 1024)
except IOError as e:
if e.errno == errno.ECONNRESET:
data = b''
is_rst = True
else:
raise
if data == b'':
# Connection closed - use is_rst to distinguish
# between RST and FIN
break
print(data)
answered Nov 17 '18 at 7:55
user4815162342user4815162342
61.8k592145
Ah thanks, and thanks to @james-k-polk : I was completely wrong in my assumptions.
– Michal Charemza
Nov 17 '18 at 8:22
add a comment |
2
2
2
Based on James K Polk's comment, which I believe to be correct, you would distinguish FIN from RST by catching the appropriate exception:
while True:
is_rst = False
try:
data = await loop.sock_recv(sock, 1024)
except IOError as e:
if e.errno == errno.ECONNRESET:
data = b''
is_rst = True
else:
raise
if data == b'':
# Connection closed - use is_rst to distinguish
# between RST and FIN
break
print(data)
answered Nov 17 '18 at 7:55
user4815162342user4815162342
61.8k592145
Based on James K Polk's comment, which I believe to be correct, you would distinguish FIN from RST by catching the appropriate exception:
while True:
is_rst = False
try:
data = await loop.sock_recv(sock, 1024)
except IOError as e:
if e.errno == errno.ECONNRESET:
data = b''
is_rst = True
else:
raise
if data == b'':
# Connection closed - use is_rst to distinguish
# between RST and FIN
break
print(data)
answered Nov 17 '18 at 7:55
user4815162342user4815162342
61.8k592145
edited Nov 17 '18 at 8:27
answered Nov 17 '18 at 7:55
user4815162342user4815162342
61.8k592145
answered Nov 17 '18 at 7:55
user4815162342user4815162342
61.8k592145
answered Nov 17 '18 at 7:55
user4815162342user4815162342
61.8k592145
61.8k592145
Ah thanks, and thanks to @james-k-polk : I was completely wrong in my assumptions.
– Michal Charemza
Nov 17 '18 at 8:22
add a comment |
Ah thanks, and thanks to @james-k-polk : I was completely wrong in my assumptions.
– Michal Charemza
Nov 17 '18 at 8:22
Ah thanks, and thanks to @james-k-polk : I was completely wrong in my assumptions.
– Michal Charemza
Nov 17 '18 at 8:22
Ah thanks, and thanks to @james-k-polk : I was completely wrong in my assumptions.
– Michal Charemza
Nov 17 '18 at 8:22
add a comment |
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2
I would expect an normal EOF condition(data == b'') only when receiving a FIN. If you receive a RST I'd expect an exception to be raised of the form "Connection reset by peer".
– James K Polk
Nov 17 '18 at 4:30