Am 15.05.21 um 16:01 schrieb Patrick Menschel: > Am 15.05.21 um 14:26 schrieb Kurt Van Dijck: >> On Fri, 14 May 2021 12:04:47 +0000, Patrick Menschel wrote: >>> Do I need to open one socket per PGN I'm sending? >>> e.g. >>> >>> s1 = socket.socket(socket.AF_CAN, socket.SOCK_DGRAM, socket.CAN_J1939) >>> s1.bind(interface_name, MY_NAME, PGN_OF_TSC1, MY_SA) >>> s1.write(bytes(8)) >>> >>> s2 = socket.socket(socket.AF_CAN, socket.SOCK_DGRAM, socket.CAN_J1939) >>> s2.bind(interface_name, MY_NAME, PGN_OF_EBC1, MY_SA) >>> s2.write(bytes(8)) >> >> No, you don't _need_ to. You can. >> >> If you need quite some different PGN's, it may be more interesting to: >> s = socket.socket(socket.AF_CAN, socket.SOCK_DGRAM, socket.CAN_J1939) >> s.bind(interface_name, MY_NAME, ANY_PGN, MY_SA) >> s.sendto(bytes(8), DST_1, PGN_1) >> s.sendto(bytes(8), DST_2, PGN_2) >> ... >> >> I'm not a python expert, I just assume something like that is possible. > > Yes, the method exists > > sendto() > https://docs.python.org/3/library/socket.html#socket.socket.sendto > https://github.com/python/cpython/blob/main/Modules/socketmodule.c#L4279 > > but apparently sockaddr_can is not yet expanded to individual parameters > as it was done with the > > bind() > https://github.com/python/cpython/blob/main/Modules/socketmodule.c#L2207 > > Then I'll start by passing in the sockaddr_can struct as a first test > and make a PR to that repo in the long run. Guess I have to amend that impression, everything works fine, except for broadcast which gives me a PermissionError ?! python -i Python 3.9.5 (default, May 13 2021, 13:29:45) [GCC 8.3.0] on linux Type "help", "copyright", "credits" or "license" for more information. >>> import socket >>> s = socket.socket(socket.AF_CAN, socket.SOCK_DGRAM, socket.CAN_J1939) >>> s.bind(("mcp0", 0, 0x40000, 0x20)) >>> s.sendto(bytes(range(8)), ("", 0, 0x12300, 0x30)) 8 >>> s.sendto(bytes(range(0,0x88,0x11)), ("", 0, 0x12300, 0x30)) 8 >>> Took me some try and error to get rid of OSError: [Errno 77] File descriptor in bad state but at least something comes out. candump mcp0 mcp0 19233020 [8] 00 01 02 03 04 05 06 07 mcp0 19233020 [8] 00 11 22 33 44 55 66 77 Maybe I didn't get the concept at all. The transport protocol also does something. s.sendto(bytes(range(64)), ("mcp0", 0, 0xFECA, 0x20)) TP.CM.RTS mcp0 18EC2020 [8] 10 40 00 0A 0A CA FE 00 TP.CM.CTS mcp0 18EC2020 [8] 11 0A 01 FF FF CA FE 00 TP.DT mcp0 18EB2020 [8] 01 00 01 02 03 04 05 06 mcp0 18EB2020 [8] 02 07 08 09 0A 0B 0C 0D mcp0 18EB2020 [8] 03 0E 0F 10 11 12 13 14 mcp0 18EB2020 [8] 04 15 16 17 18 19 1A 1B mcp0 18EB2020 [8] 05 1C 1D 1E 1F 20 21 22 mcp0 18EB2020 [8] 06 23 24 25 26 27 28 29 mcp0 18EB2020 [8] 07 2A 2B 2C 2D 2E 2F 30 mcp0 18EB2020 [8] 08 31 32 33 34 35 36 37 mcp0 18EB2020 [8] 09 38 39 3A 3B 3C 3D 3E mcp0 18EB2020 [8] 0A 3F FF FF FF FF FF FF TP.CM.EndMsgAck mcp0 18EC2020 [8] 13 40 00 0A FF CA FE 00 Those with a little knowledge of J1939 will now roll on the floor ;-) The only thing that I didn't get to work is send to broadcast. That PermissionError is somewhat strange. >>> s.sendto(bytes(range(8)), ("", 0, 0xFECA, 0xFF)) Traceback (most recent call last): File "<stdin>", line 1, in <module> PermissionError: [Errno 13] Permission denied >>> s.sendto(bytes(range(64)), ("mcp0", 0, 0xFECA, 0xFF)) Traceback (most recent call last): File "<stdin>", line 1, in <module> PermissionError: [Errno 13] Permission denied Best Regards, Patrick
