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can: add support of SAE J1939 protocol

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SAE J1939 is the vehicle bus recommended practice used for communication
and diagnostics among vehicle components. Originating in the car and
heavy-duty truck industry in the United States, it is now widely used in
other parts of the world.

J1939, ISO 11783 and NMEA 2000 all share the same high level protocol.
SAE J1939 can be considered the replacement for the older SAE J1708 and
SAE J1587 specifications.

Acked-by: Oliver Hartkopp <socketcan@hartkopp.net>
Signed-off-by: Bastian Stender <bst@pengutronix.de>
Signed-off-by: Elenita Hinds <ecathinds@gmail.com>
Signed-off-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Kurt Van Dijck <dev.kurt@vandijck-laurijssen.be>
Signed-off-by: Maxime Jayat <maxime.jayat@mobile-devices.fr>
Signed-off-by: Robin van der Gracht <robin@protonic.nl>
Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
This commit is contained in:
The j1939 authors 2018-10-08 11:48:36 +02:00 committed by Marc Kleine-Budde
parent f5223e9eee
commit 9d71dd0c70
15 changed files with 5055 additions and 0 deletions
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1
Documentation/networking/index.rst
View file

@ -17,6 +17,7 @@ Contents:
devlink-trap
devlink-trap-netdevsim
ieee802154
j1939
kapi
z8530book
msg_zerocopy

422
Documentation/networking/j1939.rst Normal file
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@ -0,0 +1,422 @@
.. SPDX-License-Identifier: (GPL-2.0 OR MIT)
===================
J1939 Documentation
===================
Overview / What Is J1939
========================
SAE J1939 defines a higher layer protocol on CAN. It implements a more
sophisticated addressing scheme and extends the maximum packet size above 8
bytes. Several derived specifications exist, which differ from the original
J1939 on the application level, like MilCAN A, NMEA2000 and especially
ISO-11783 (ISOBUS). This last one specifies the so-called ETP (Extended
Transport Protocol) which is has been included in this implementation. This
results in a maximum packet size of ((2 ^ 24) - 1) * 7 bytes == 111 MiB.
Specifications used
-------------------
* SAE J1939-21 : data link layer
* SAE J1939-81 : network management
* ISO 11783-6 : Virtual Terminal (Extended Transport Protocol)
.. _j1939-motivation:
Motivation
==========
Given the fact there's something like SocketCAN with an API similar to BSD
sockets, we found some reasons to justify a kernel implementation for the
addressing and transport methods used by J1939.
* **Addressing:** when a process on an ECU communicates via J1939, it should
not necessarily know its source address. Although at least one process per
ECU should know the source address. Other processes should be able to reuse
that address. This way, address parameters for different processes
cooperating for the same ECU, are not duplicated. This way of working is
closely related to the UNIX concept where programs do just one thing, and do
it well.
* **Dynamic addressing:** Address Claiming in J1939 is time critical.
Furthermore data transport should be handled properly during the address
negotiation. Putting this functionality in the kernel eliminates it as a
requirement for _every_ user space process that communicates via J1939. This
results in a consistent J1939 bus with proper addressing.
* **Transport:** both TP & ETP reuse some PGNs to relay big packets over them.
Different processes may thus use the same TP & ETP PGNs without actually
knowing it. The individual TP & ETP sessions _must_ be serialized
(synchronized) between different processes. The kernel solves this problem
properly and eliminates the serialization (synchronization) as a requirement
for _every_ user space process that communicates via J1939.
J1939 defines some other features (relaying, gateway, fast packet transport,
...). In-kernel code for these would not contribute to protocol stability.
Therefore, these parts are left to user space.
The J1939 sockets operate on CAN network devices (see SocketCAN). Any J1939
user space library operating on CAN raw sockets will still operate properly.
Since such library does not communicate with the in-kernel implementation, care
must be taken that these two do not interfere. In practice, this means they
cannot share ECU addresses. A single ECU (or virtual ECU) address is used by
the library exclusively, or by the in-kernel system exclusively.
J1939 concepts
==============
PGN
---
The PGN (Parameter Group Number) is a number to identify a packet. The PGN
is composed as follows:
1 bit : Reserved Bit
1 bit : Data Page
8 bits : PF (PDU Format)
8 bits : PS (PDU Specific)
In J1939-21 distinction is made between PDU1 format (where PF < 240) and PDU2
format (where PF >= 240). Furthermore, when using PDU2 format, the PS-field
contains a so-called Group Extension, which is part of the PGN. When using PDU2
format, the Group Extension is set in the PS-field.
On the other hand, when using PDU1 format, the PS-field contains a so-called
Destination Address, which is _not_ part of the PGN. When communicating a PGN
from user space to kernel (or visa versa) and PDU2 format is used, the PS-field
of the PGN shall be set to zero. The Destination Address shall be set
elsewhere.
Regarding PGN mapping to 29-bit CAN identifier, the Destination Address shall
be get/set from/to the appropriate bits of the identifier by the kernel.
Addressing
----------
Both static and dynamic addressing methods can be used.
For static addresses, no extra checks are made by the kernel, and provided
addresses are considered right. This responsibility is for the OEM or system
integrator.
For dynamic addressing, so-called Address Claiming, extra support is foreseen
in the kernel. In J1939 any ECU is known by it's 64-bit NAME. At the moment of
a successful address claim, the kernel keeps track of both NAME and source
address being claimed. This serves as a base for filter schemes. By default,
packets with a destination that is not locally, will be rejected.
Mixed mode packets (from a static to a dynamic address or vice versa) are
allowed. The BSD sockets define separate API calls for getting/setting the
local & remote address and are applicable for J1939 sockets.
Filtering
---------
J1939 defines white list filters per socket that a user can set in order to
receive a subset of the J1939 traffic. Filtering can be based on:
* SA
* SOURCE_NAME
* PGN
When multiple filters are in place for a single socket, and a packet comes in
that matches several of those filters, the packet is only received once for
that socket.
How to Use J1939
================
API Calls
---------
On CAN, you first need to open a socket for communicating over a CAN network.
To use J1939, #include <linux/can/j1939.h>. From there, <linux/can.h> will be
included too. To open a socket, use:
.. code-block:: C
s = socket(PF_CAN, SOCK_DGRAM, CAN_J1939);
J1939 does use SOCK_DGRAM sockets. In the J1939 specification, connections are
mentioned in the context of transport protocol sessions. These still deliver
packets to the other end (using several CAN packets). SOCK_STREAM is not
supported.
After the successful creation of the socket, you would normally use the bind(2)
and/or connect(2) system call to bind the socket to a CAN interface. After
binding and/or connecting the socket, you can read(2) and write(2) from/to the
socket or use send(2), sendto(2), sendmsg(2) and the recv*() counterpart
operations on the socket as usual. There are also J1939 specific socket options
described below.
In order to send data, a bind(2) must have been successful. bind(2) assigns a
local address to a socket.
Different from CAN is that the payload data is just the data that get send,
without it's header info. The header info is derived from the sockaddr supplied
to bind(2), connect(2), sendto(2) and recvfrom(2). A write(2) with size 4 will
result in a packet with 4 bytes.
The sockaddr structure has extensions for use with J1939 as specified below:
.. code-block:: C
struct sockaddr_can {
sa_family_t can_family;
int can_ifindex;
union {
struct {
__u64 name;
/* pgn:
* 8 bit: PS in PDU2 case, else 0
* 8 bit: PF
* 1 bit: DP
* 1 bit: reserved
*/
__u32 pgn;
__u8 addr;
} j1939;
} can_addr;
}
can_family & can_ifindex serve the same purpose as for other SocketCAN sockets.
can_addr.j1939.pgn specifies the PGN (max 0x3ffff). Individual bits are
specified above.
can_addr.j1939.name contains the 64-bit J1939 NAME.
can_addr.j1939.addr contains the address.
The bind(2) system call assigns the local address, i.e. the source address when
sending packages. If a PGN during bind(2) is set, it's used as a RX filter.
I.e. only packets with a matching PGN are received. If an ADDR or NAME is set
it is used as a receive filter, too. It will match the destination NAME or ADDR
of the incoming packet. The NAME filter will work only if appropriate Address
Claiming for this name was done on the CAN bus and registered/cached by the
kernel.
On the other hand connect(2) assigns the remote address, i.e. the destination
address. The PGN from connect(2) is used as the default PGN when sending
packets. If ADDR or NAME is set it will be used as the default destination ADDR
or NAME. Further a set ADDR or NAME during connect(2) is used as a receive
filter. It will match the source NAME or ADDR of the incoming packet.
Both write(2) and send(2) will send a packet with local address from bind(2) and
the remote address from connect(2). Use sendto(2) to overwrite the destination
address.
If can_addr.j1939.name is set (!= 0) the NAME is looked up by the kernel and
the corresponding ADDR is used. If can_addr.j1939.name is not set (== 0),
can_addr.j1939.addr is used.
When creating a socket, reasonable defaults are set. Some options can be
modified with setsockopt(2) & getsockopt(2).
RX path related options:
- SO_J1939_FILTER - configure array of filters
- SO_J1939_PROMISC - disable filters set by bind(2) and connect(2)
By default no broadcast packets can be send or received. To enable sending or
receiving broadcast packets use the socket option SO_BROADCAST:
.. code-block:: C
int value = 1;
setsockopt(sock, SOL_SOCKET, SO_BROADCAST, &value, sizeof(value));
The following diagram illustrates the RX path:
.. code::
+--------------------+
| incoming packet |
+--------------------+
|
V
+--------------------+
| SO_J1939_PROMISC? |
+--------------------+
| |
no | | yes
| |
.---------' `---------.
| |
+---------------------------+ |
| bind() + connect() + | |
| SOCK_BROADCAST filter | |
+---------------------------+ |
| |
|<---------------------'
V
+---------------------------+
| SO_J1939_FILTER |
+---------------------------+
|
V
+---------------------------+
| socket recv() |
+---------------------------+
TX path related options:
SO_J1939_SEND_PRIO - change default send priority for the socket
Message Flags during send() and Related System Calls
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
send(2), sendto(2) and sendmsg(2) take a 'flags' argument. Currently
supported flags are:
* MSG_DONTWAIT, i.e. non-blocking operation.
recvmsg(2)
^^^^^^^^^
In most cases recvmsg(2) is needed if you want to extract more information than
recvfrom(2) can provide. For example package priority and timestamp. The
Destination Address, name and packet priority (if applicable) are attached to
the msghdr in the recvmsg(2) call. They can be extracted using cmsg(3) macros,
with cmsg_level == SOL_J1939 && cmsg_type == SCM_J1939_DEST_ADDR,
SCM_J1939_DEST_NAME or SCM_J1939_PRIO. The returned data is a uint8_t for
priority and dst_addr, and uint64_t for dst_name.
.. code-block:: C
uint8_t priority, dst_addr;
uint64_t dst_name;
for (cmsg = CMSG_FIRSTHDR(&msg); cmsg; cmsg = CMSG_NXTHDR(&msg, cmsg)) {
switch (cmsg->cmsg_level) {
case SOL_CAN_J1939:
if (cmsg->cmsg_type == SCM_J1939_DEST_ADDR)
dst_addr = *CMSG_DATA(cmsg);
else if (cmsg->cmsg_type == SCM_J1939_DEST_NAME)
memcpy(&dst_name, CMSG_DATA(cmsg), cmsg->cmsg_len - CMSG_LEN(0));
else if (cmsg->cmsg_type == SCM_J1939_PRIO)
priority = *CMSG_DATA(cmsg);
break;
}
}
Dynamic Addressing
------------------
Distinction has to be made between using the claimed address and doing an
address claim. To use an already claimed address, one has to fill in the
j1939.name member and provide it to bind(2). If the name had claimed an address
earlier, all further messages being sent will use that address. And the
j1939.addr member will be ignored.
An exception on this is PGN 0x0ee00. This is the "Address Claim/Cannot Claim
Address" message and the kernel will use the j1939.addr member for that PGN if
necessary.
To claim an address following code example can be used:
.. code-block:: C
struct sockaddr_can baddr = {
.can_family = AF_CAN,
.can_addr.j1939 = {
.name = name,
.addr = J1939_IDLE_ADDR,
.pgn = J1939_NO_PGN, /* to disable bind() rx filter for PGN */
},
.can_ifindex = if_nametoindex("can0"),
};
bind(sock, (struct sockaddr *)&baddr, sizeof(baddr));
/* for Address Claiming broadcast must be allowed */
int value = 1;
setsockopt(sock, SOL_SOCKET, SO_BROADCAST, &value, sizeof(value));
/* configured advanced RX filter with PGN needed for Address Claiming */
const struct j1939_filter filt[] = {
{
.pgn = J1939_PGN_ADDRESS_CLAIMED,
.pgn_mask = J1939_PGN_PDU1_MAX,
}, {
.pgn = J1939_PGN_ADDRESS_REQUEST,
.pgn_mask = J1939_PGN_PDU1_MAX,
}, {
.pgn = J1939_PGN_ADDRESS_COMMANDED,
.pgn_mask = J1939_PGN_MAX,
},
};
setsockopt(sock, SOL_CAN_J1939, SO_J1939_FILTER, &filt, sizeof(filt));
uint64_t dat = htole64(name);
const struct sockaddr_can saddr = {
.can_family = AF_CAN,
.can_addr.j1939 = {
.pgn = J1939_PGN_ADDRESS_CLAIMED,
.addr = J1939_NO_ADDR,
},
};
/* Afterwards do a sendto(2) with data set to the NAME (Little Endian). If the
* NAME provided, does not match the j1939.name provided to bind(2), EPROTO
* will be returned.
*/
sendto(sock, dat, sizeof(dat), 0, (const struct sockaddr *)&saddr, sizeof(saddr));
If no-one else contests the address claim within 250ms after transmission, the
kernel marks the NAME-SA assignment as valid. The valid assignment will be kept
among other valid NAME-SA assignments. From that point, any socket bound to the
NAME can send packets.
If another ECU claims the address, the kernel will mark the NAME-SA expired.
No socket bound to the NAME can send packets (other than address claims). To
claim another address, some socket bound to NAME, must bind(2) again, but with
only j1939.addr changed to the new SA, and must then send a valid address claim
packet. This restarts the state machine in the kernel (and any other
participant on the bus) for this NAME.
can-utils also include the jacd tool, so it can be used as code example or as
default Address Claiming daemon.
Send Examples
-------------
Static Addressing
^^^^^^^^^^^^^^^^^
This example will send a PGN (0x12300) from SA 0x20 to DA 0x30.
Bind:
.. code-block:: C
struct sockaddr_can baddr = {
.can_family = AF_CAN,
.can_addr.j1939 = {
.name = J1939_NO_NAME,
.addr = 0x20,
.pgn = J1939_NO_PGN,
},
.can_ifindex = if_nametoindex("can0"),
};
bind(sock, (struct sockaddr *)&baddr, sizeof(baddr));
Now, the socket 'sock' is bound to the SA 0x20. Since no connect(2) was called,
at this point we can use only sendto(2) or sendmsg(2).
Send:
.. code-block:: C
const struct sockaddr_can saddr = {
.can_family = AF_CAN,
.can_addr.j1939 = {
.name = J1939_NO_NAME;
.pgn = 0x30,
.addr = 0x12300,
},
};
sendto(sock, dat, sizeof(dat), 0, (const struct sockaddr *)&saddr, sizeof(saddr));

10
MAINTAINERS
View file

@ -3669,6 +3669,16 @@ F: include/uapi/linux/can/bcm.h
F: include/uapi/linux/can/raw.h
F: include/uapi/linux/can/gw.h
CAN-J1939 NETWORK LAYER
M: Robin van der Gracht <robin@protonic.nl>
M: Oleksij Rempel <o.rempel@pengutronix.de>
R: Pengutronix Kernel Team <kernel@pengutronix.de>
L: linux-can@vger.kernel.org
S: Maintained
F: Documentation/networking/j1939.txt
F: net/can/j1939/
F: include/uapi/linux/can/j1939.h
CAPABILITIES
M: Serge Hallyn <serge@hallyn.com>
L: linux-security-module@vger.kernel.org

3
include/linux/can/can-ml.h
View file

@ -60,6 +60,9 @@ struct can_dev_rcv_lists {
struct can_ml_priv {
struct can_dev_rcv_lists dev_rcv_lists;
#ifdef CAN_J1939
struct j1939_priv *j1939_priv;
#endif
};
#endif /* CAN_ML_H */

99
include/uapi/linux/can/j1939.h Normal file
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@ -0,0 +1,99 @@
/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
/*
* j1939.h
*
* Copyright (c) 2010-2011 EIA Electronics
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#ifndef _UAPI_CAN_J1939_H_
#define _UAPI_CAN_J1939_H_
#include <linux/types.h>
#include <linux/socket.h>
#include <linux/can.h>
#define J1939_MAX_UNICAST_ADDR 0xfd
#define J1939_IDLE_ADDR 0xfe
#define J1939_NO_ADDR 0xff /* == broadcast or no addr */
#define J1939_NO_NAME 0
#define J1939_PGN_REQUEST 0x0ea00 /* Request PG */
#define J1939_PGN_ADDRESS_CLAIMED 0x0ee00 /* Address Claimed */
#define J1939_PGN_ADDRESS_COMMANDED 0x0fed8 /* Commanded Address */
#define J1939_PGN_PDU1_MAX 0x3ff00
#define J1939_PGN_MAX 0x3ffff
#define J1939_NO_PGN 0x40000
/* J1939 Parameter Group Number
*
* bit 0-7 : PDU Specific (PS)
* bit 8-15 : PDU Format (PF)
* bit 16 : Data Page (DP)
* bit 17 : Reserved (R)
* bit 19-31 : set to zero
*/
typedef __u32 pgn_t;
/* J1939 Priority
*
* bit 0-2 : Priority (P)
* bit 3-7 : set to zero
*/
typedef __u8 priority_t;
/* J1939 NAME
*
* bit 0-20 : Identity Number
* bit 21-31 : Manufacturer Code
* bit 32-34 : ECU Instance
* bit 35-39 : Function Instance
* bit 40-47 : Function
* bit 48 : Reserved
* bit 49-55 : Vehicle System
* bit 56-59 : Vehicle System Instance
* bit 60-62 : Industry Group
* bit 63 : Arbitrary Address Capable
*/
typedef __u64 name_t;
/* J1939 socket options */
#define SOL_CAN_J1939 (SOL_CAN_BASE + CAN_J1939)
enum {
SO_J1939_FILTER = 1, /* set filters */
SO_J1939_PROMISC = 2, /* set/clr promiscuous mode */
SO_J1939_SEND_PRIO = 3,
SO_J1939_ERRQUEUE = 4,
};
enum {
SCM_J1939_DEST_ADDR = 1,
SCM_J1939_DEST_NAME = 2,
SCM_J1939_PRIO = 3,
SCM_J1939_ERRQUEUE = 4,
};
enum {
J1939_NLA_PAD,
J1939_NLA_BYTES_ACKED,
};
enum {
J1939_EE_INFO_NONE,
J1939_EE_INFO_TX_ABORT,
};
struct j1939_filter {
name_t name;
name_t name_mask;
pgn_t pgn;
pgn_t pgn_mask;
__u8 addr;
__u8 addr_mask;
};
#define J1939_FILTER_MAX 512 /* maximum number of j1939_filter set via setsockopt() */
#endif /* !_UAPI_CAN_J1939_H_ */

2
net/can/Kconfig
View file

@ -53,6 +53,8 @@ config CAN_GW
They can be modified with AND/OR/XOR/SET operations as configured
by the netlink configuration interface known e.g. from iptables.
source "net/can/j1939/Kconfig"
source "drivers/net/can/Kconfig"
endif

2
net/can/Makefile
View file

@ -15,3 +15,5 @@ can-bcm-y := bcm.o
obj-$(CONFIG_CAN_GW) += can-gw.o
can-gw-y := gw.o
obj-$(CONFIG_CAN_J1939) += j1939/

15
net/can/j1939/Kconfig Normal file
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@ -0,0 +1,15 @@
# SPDX-License-Identifier: GPL-2.0
#
# SAE J1939 network layer core configuration
#
config CAN_J1939
tristate "SAE J1939"
depends on CAN
help
SAE J1939
Say Y to have in-kernel support for j1939 socket type. This
allows communication according to SAE j1939.
The relevant parts in kernel are
SAE j1939-21 (datalink & transport protocol)
& SAE j1939-81 (network management).

10
net/can/j1939/Makefile Normal file
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@ -0,0 +1,10 @@
# SPDX-License-Identifier: GPL-2.0
obj-$(CONFIG_CAN_J1939) += can-j1939.o
can-j1939-objs := \
address-claim.o \
bus.o \
main.o \
socket.o \
transport.o

230
net/can/j1939/address-claim.c Normal file
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@ -0,0 +1,230 @@
// SPDX-License-Identifier: GPL-2.0
// Copyright (c) 2010-2011 EIA Electronics,
// Kurt Van Dijck <kurt.van.dijck@eia.be>
// Copyright (c) 2010-2011 EIA Electronics,
// Pieter Beyens <pieter.beyens@eia.be>
// Copyright (c) 2017-2019 Pengutronix,
// Marc Kleine-Budde <kernel@pengutronix.de>
// Copyright (c) 2017-2019 Pengutronix,
// Oleksij Rempel <kernel@pengutronix.de>
/* J1939 Address Claiming.
* Address Claiming in the kernel
* - keeps track of the AC states of ECU's,
* - resolves NAME<=>SA taking into account the AC states of ECU's.
*
* All Address Claim msgs (including host-originated msg) are processed
* at the receive path (a sent msg is always received again via CAN echo).
* As such, the processing of AC msgs is done in the order on which msgs
* are sent on the bus.
*
* This module doesn't send msgs itself (e.g. replies on Address Claims),
* this is the responsibility of a user space application or daemon.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/netdevice.h>
#include <linux/skbuff.h>
#include "j1939-priv.h"
static inline name_t j1939_skb_to_name(const struct sk_buff *skb)
{
return le64_to_cpup((__le64 *)skb->data);
}
static inline bool j1939_ac_msg_is_request(struct sk_buff *skb)
{
struct j1939_sk_buff_cb *skcb = j1939_skb_to_cb(skb);
int req_pgn;
if (skb->len < 3 || skcb->addr.pgn != J1939_PGN_REQUEST)
return false;
req_pgn = skb->data[0] | (skb->data[1] << 8) | (skb->data[2] << 16);
return req_pgn == J1939_PGN_ADDRESS_CLAIMED;
}
static int j1939_ac_verify_outgoing(struct j1939_priv *priv,
struct sk_buff *skb)
{
struct j1939_sk_buff_cb *skcb = j1939_skb_to_cb(skb);
if (skb->len != 8) {
netdev_notice(priv->ndev, "tx address claim with dlc %i\n",
skb->len);
return -EPROTO;
}
if (skcb->addr.src_name != j1939_skb_to_name(skb)) {
netdev_notice(priv->ndev, "tx address claim with different name\n");
return -EPROTO;
}
if (skcb->addr.sa == J1939_NO_ADDR) {
netdev_notice(priv->ndev, "tx address claim with broadcast sa\n");
return -EPROTO;
}
/* ac must always be a broadcast */
if (skcb->addr.dst_name || skcb->addr.da != J1939_NO_ADDR) {
netdev_notice(priv->ndev, "tx address claim with dest, not broadcast\n");
return -EPROTO;
}
return 0;
}
int j1939_ac_fixup(struct j1939_priv *priv, struct sk_buff *skb)
{
struct j1939_sk_buff_cb *skcb = j1939_skb_to_cb(skb);
int ret;
u8 addr;
/* network mgmt: address claiming msgs */
if (skcb->addr.pgn == J1939_PGN_ADDRESS_CLAIMED) {
struct j1939_ecu *ecu;
ret = j1939_ac_verify_outgoing(priv, skb);
/* return both when failure & when successful */
if (ret < 0)
return ret;
ecu = j1939_ecu_get_by_name(priv, skcb->addr.src_name);
if (!ecu)
return -ENODEV;
if (ecu->addr != skcb->addr.sa)
/* hold further traffic for ecu, remove from parent */
j1939_ecu_unmap(ecu);
j1939_ecu_put(ecu);
} else if (skcb->addr.src_name) {
/* assign source address */
addr = j1939_name_to_addr(priv, skcb->addr.src_name);
if (!j1939_address_is_unicast(addr) &&
!j1939_ac_msg_is_request(skb)) {
netdev_notice(priv->ndev, "tx drop: invalid sa for name 0x%016llx\n",
skcb->addr.src_name);
return -EADDRNOTAVAIL;
}
skcb->addr.sa = addr;
}
/* assign destination address */
if (skcb->addr.dst_name) {
addr = j1939_name_to_addr(priv, skcb->addr.dst_name);
if (!j1939_address_is_unicast(addr)) {
netdev_notice(priv->ndev, "tx drop: invalid da for name 0x%016llx\n",
skcb->addr.dst_name);
return -EADDRNOTAVAIL;
}
skcb->addr.da = addr;
}
return 0;
}
static void j1939_ac_process(struct j1939_priv *priv, struct sk_buff *skb)
{
struct j1939_sk_buff_cb *skcb = j1939_skb_to_cb(skb);
struct j1939_ecu *ecu, *prev;
name_t name;
if (skb->len != 8) {
netdev_notice(priv->ndev, "rx address claim with wrong dlc %i\n",
skb->len);
return;
}
name = j1939_skb_to_name(skb);
skcb->addr.src_name = name;
if (!name) {
netdev_notice(priv->ndev, "rx address claim without name\n");
return;
}
if (!j1939_address_is_valid(skcb->addr.sa)) {
netdev_notice(priv->ndev, "rx address claim with broadcast sa\n");
return;
}
write_lock_bh(&priv->lock);
/* Few words on the ECU ref counting:
*
* First we get an ECU handle, either with
* j1939_ecu_get_by_name_locked() (increments the ref counter)
* or j1939_ecu_create_locked() (initializes an ECU object
* with a ref counter of 1).
*
* j1939_ecu_unmap_locked() will decrement the ref counter,
* but only if the ECU was mapped before. So "ecu" still
* belongs to us.
*
* j1939_ecu_timer_start() will increment the ref counter
* before it starts the timer, so we can put the ecu when
* leaving this function.
*/
ecu = j1939_ecu_get_by_name_locked(priv, name);
if (!ecu && j1939_address_is_unicast(skcb->addr.sa))
ecu = j1939_ecu_create_locked(priv, name);
if (IS_ERR_OR_NULL(ecu))
goto out_unlock_bh;
/* cancel pending (previous) address claim */
j1939_ecu_timer_cancel(ecu);
if (j1939_address_is_idle(skcb->addr.sa)) {
j1939_ecu_unmap_locked(ecu);
goto out_ecu_put;
}
/* save new addr */
if (ecu->addr != skcb->addr.sa)
j1939_ecu_unmap_locked(ecu);
ecu->addr = skcb->addr.sa;
prev = j1939_ecu_get_by_addr_locked(priv, skcb->addr.sa);
if (prev) {
if (ecu->name > prev->name) {
j1939_ecu_unmap_locked(ecu);
j1939_ecu_put(prev);
goto out_ecu_put;
} else {
/* kick prev if less or equal */
j1939_ecu_unmap_locked(prev);
j1939_ecu_put(prev);
}
}
j1939_ecu_timer_start(ecu);
out_ecu_put:
j1939_ecu_put(ecu);
out_unlock_bh:
write_unlock_bh(&priv->lock);
}
void j1939_ac_recv(struct j1939_priv *priv, struct sk_buff *skb)
{
struct j1939_sk_buff_cb *skcb = j1939_skb_to_cb(skb);
struct j1939_ecu *ecu;
/* network mgmt */
if (skcb->addr.pgn == J1939_PGN_ADDRESS_CLAIMED) {
j1939_ac_process(priv, skb);
} else if (j1939_address_is_unicast(skcb->addr.sa)) {
/* assign source name */
ecu = j1939_ecu_get_by_addr(priv, skcb->addr.sa);
if (ecu) {
skcb->addr.src_name = ecu->name;
j1939_ecu_put(ecu);
}
}
/* assign destination name */
ecu = j1939_ecu_get_by_addr(priv, skcb->addr.da);
if (ecu) {
skcb->addr.dst_name = ecu->name;
j1939_ecu_put(ecu);
}
}

333
net/can/j1939/bus.c Normal file
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// SPDX-License-Identifier: GPL-2.0
// Copyright (c) 2010-2011 EIA Electronics,
// Kurt Van Dijck <kurt.van.dijck@eia.be>
// Copyright (c) 2017-2019 Pengutronix,
// Marc Kleine-Budde <kernel@pengutronix.de>
// Copyright (c) 2017-2019 Pengutronix,
// Oleksij Rempel <kernel@pengutronix.de>
/* bus for j1939 remote devices
* Since rtnetlink, no real bus is used.
*/
#include <net/sock.h>
#include "j1939-priv.h"
static void __j1939_ecu_release(struct kref *kref)
{
struct j1939_ecu *ecu = container_of(kref, struct j1939_ecu, kref);
struct j1939_priv *priv = ecu->priv;
list_del(&ecu->list);
kfree(ecu);
j1939_priv_put(priv);
}
void j1939_ecu_put(struct j1939_ecu *ecu)
{
kref_put(&ecu->kref, __j1939_ecu_release);
}
static void j1939_ecu_get(struct j1939_ecu *ecu)
{
kref_get(&ecu->kref);
}
static bool j1939_ecu_is_mapped_locked(struct j1939_ecu *ecu)
{
struct j1939_priv *priv = ecu->priv;
lockdep_assert_held(&priv->lock);
return j1939_ecu_find_by_addr_locked(priv, ecu->addr) == ecu;
}
/* ECU device interface */
/* map ECU to a bus address space */
static void j1939_ecu_map_locked(struct j1939_ecu *ecu)
{
struct j1939_priv *priv = ecu->priv;
struct j1939_addr_ent *ent;
lockdep_assert_held(&priv->lock);
if (!j1939_address_is_unicast(ecu->addr))
return;
ent = &priv->ents[ecu->addr];
if (ent->ecu) {
netdev_warn(priv->ndev, "Trying to map already mapped ECU, addr: 0x%02x, name: 0x%016llx. Skip it.\n",
ecu->addr, ecu->name);
return;
}
j1939_ecu_get(ecu);
ent->ecu = ecu;
ent->nusers += ecu->nusers;
}
/* unmap ECU from a bus address space */
void j1939_ecu_unmap_locked(struct j1939_ecu *ecu)
{
struct j1939_priv *priv = ecu->priv;
struct j1939_addr_ent *ent;
lockdep_assert_held(&priv->lock);
if (!j1939_address_is_unicast(ecu->addr))
return;
if (!j1939_ecu_is_mapped_locked(ecu))
return;
ent = &priv->ents[ecu->addr];
ent->ecu = NULL;
ent->nusers -= ecu->nusers;
j1939_ecu_put(ecu);
}
void j1939_ecu_unmap(struct j1939_ecu *ecu)
{
write_lock_bh(&ecu->priv->lock);
j1939_ecu_unmap_locked(ecu);
write_unlock_bh(&ecu->priv->lock);
}
void j1939_ecu_unmap_all(struct j1939_priv *priv)
{
int i;
write_lock_bh(&priv->lock);
for (i = 0; i < ARRAY_SIZE(priv->ents); i++)
if (priv->ents[i].ecu)
j1939_ecu_unmap_locked(priv->ents[i].ecu);
write_unlock_bh(&priv->lock);
}
void j1939_ecu_timer_start(struct j1939_ecu *ecu)
{
/* The ECU is held here and released in the
* j1939_ecu_timer_handler() or j1939_ecu_timer_cancel().
*/
j1939_ecu_get(ecu);
/* Schedule timer in 250 msec to commit address change. */
hrtimer_start(&ecu->ac_timer, ms_to_ktime(250),
HRTIMER_MODE_REL_SOFT);
}
void j1939_ecu_timer_cancel(struct j1939_ecu *ecu)
{
if (hrtimer_cancel(&ecu->ac_timer))
j1939_ecu_put(ecu);
}
static enum hrtimer_restart j1939_ecu_timer_handler(struct hrtimer *hrtimer)
{
struct j1939_ecu *ecu =
container_of(hrtimer, struct j1939_ecu, ac_timer);
struct j1939_priv *priv = ecu->priv;
write_lock_bh(&priv->lock);
/* TODO: can we test if ecu->addr is unicast before starting
* the timer?
*/
j1939_ecu_map_locked(ecu);
/* The corresponding j1939_ecu_get() is in
* j1939_ecu_timer_start().
*/
j1939_ecu_put(ecu);
write_unlock_bh(&priv->lock);
return HRTIMER_NORESTART;
}
struct j1939_ecu *j1939_ecu_create_locked(struct j1939_priv *priv, name_t name)
{
struct j1939_ecu *ecu;
lockdep_assert_held(&priv->lock);
ecu = kzalloc(sizeof(*ecu), gfp_any());
if (!ecu)
return ERR_PTR(-ENOMEM);
kref_init(&ecu->kref);
ecu->addr = J1939_IDLE_ADDR;
ecu->name = name;
hrtimer_init(&ecu->ac_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_SOFT);
ecu->ac_timer.function = j1939_ecu_timer_handler;
INIT_LIST_HEAD(&ecu->list);
j1939_priv_get(priv);
ecu->priv = priv;
list_add_tail(&ecu->list, &priv->ecus);
return ecu;
}
struct j1939_ecu *j1939_ecu_find_by_addr_locked(struct j1939_priv *priv,
u8 addr)
{
lockdep_assert_held(&priv->lock);
return priv->ents[addr].ecu;
}
struct j1939_ecu *j1939_ecu_get_by_addr_locked(struct j1939_priv *priv, u8 addr)
{
struct j1939_ecu *ecu;
lockdep_assert_held(&priv->lock);
if (!j1939_address_is_unicast(addr))
return NULL;
ecu = j1939_ecu_find_by_addr_locked(priv, addr);
if (ecu)
j1939_ecu_get(ecu);
return ecu;
}
struct j1939_ecu *j1939_ecu_get_by_addr(struct j1939_priv *priv, u8 addr)
{
struct j1939_ecu *ecu;
read_lock_bh(&priv->lock);
ecu = j1939_ecu_get_by_addr_locked(priv, addr);
read_unlock_bh(&priv->lock);
return ecu;
}
/* get pointer to ecu without increasing ref counter */
static struct j1939_ecu *j1939_ecu_find_by_name_locked(struct j1939_priv *priv,
name_t name)
{
struct j1939_ecu *ecu;
lockdep_assert_held(&priv->lock);
list_for_each_entry(ecu, &priv->ecus, list) {
if (ecu->name == name)
return ecu;
}
return NULL;
}
struct j1939_ecu *j1939_ecu_get_by_name_locked(struct j1939_priv *priv,
name_t name)
{
struct j1939_ecu *ecu;
lockdep_assert_held(&priv->lock);
if (!name)
return NULL;
ecu = j1939_ecu_find_by_name_locked(priv, name);
if (ecu)
j1939_ecu_get(ecu);
return ecu;
}
struct j1939_ecu *j1939_ecu_get_by_name(struct j1939_priv *priv, name_t name)
{
struct j1939_ecu *ecu;
read_lock_bh(&priv->lock);
ecu = j1939_ecu_get_by_name_locked(priv, name);
read_unlock_bh(&priv->lock);
return ecu;
}
u8 j1939_name_to_addr(struct j1939_priv *priv, name_t name)
{
struct j1939_ecu *ecu;
int addr = J1939_IDLE_ADDR;
if (!name)
return J1939_NO_ADDR;
read_lock_bh(&priv->lock);
ecu = j1939_ecu_find_by_name_locked(priv, name);
if (ecu && j1939_ecu_is_mapped_locked(ecu))
/* ecu's SA is registered */
addr = ecu->addr;
read_unlock_bh(&priv->lock);
return addr;
}
/* TX addr/name accounting
* Transport protocol needs to know if a SA is local or not
* These functions originate from userspace manipulating sockets,
* so locking is straigforward
*/
int j1939_local_ecu_get(struct j1939_priv *priv, name_t name, u8 sa)
{
struct j1939_ecu *ecu;
int err = 0;
write_lock_bh(&priv->lock);
if (j1939_address_is_unicast(sa))
priv->ents[sa].nusers++;
if (!name)
goto done;
ecu = j1939_ecu_get_by_name_locked(priv, name);
if (!ecu)
ecu = j1939_ecu_create_locked(priv, name);
err = PTR_ERR_OR_ZERO(ecu);
if (err)
goto done;
ecu->nusers++;
/* TODO: do we care if ecu->addr != sa? */
if (j1939_ecu_is_mapped_locked(ecu))
/* ecu's sa is active already */
priv->ents[ecu->addr].nusers++;
done:
write_unlock_bh(&priv->lock);
return err;
}
void j1939_local_ecu_put(struct j1939_priv *priv, name_t name, u8 sa)
{
struct j1939_ecu *ecu;
write_lock_bh(&priv->lock);
if (j1939_address_is_unicast(sa))
priv->ents[sa].nusers--;
if (!name)
goto done;
ecu = j1939_ecu_find_by_name_locked(priv, name);
if (WARN_ON_ONCE(!ecu))
goto done;
ecu->nusers--;
/* TODO: do we care if ecu->addr != sa? */
if (j1939_ecu_is_mapped_locked(ecu))
/* ecu's sa is active already */
priv->ents[ecu->addr].nusers--;
j1939_ecu_put(ecu);
done:
write_unlock_bh(&priv->lock);
}

338
net/can/j1939/j1939-priv.h Normal file
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/* SPDX-License-Identifier: GPL-2.0 */
// Copyright (c) 2010-2011 EIA Electronics,
// Kurt Van Dijck <kurt.van.dijck@eia.be>
// Copyright (c) 2017-2019 Pengutronix,
// Marc Kleine-Budde <kernel@pengutronix.de>
// Copyright (c) 2017-2019 Pengutronix,
// Oleksij Rempel <kernel@pengutronix.de>
#ifndef _J1939_PRIV_H_
#define _J1939_PRIV_H_
#include <linux/can/j1939.h>
#include <net/sock.h>
/* Timeout to receive the abort signal over loop back. In case CAN
* bus is open, the timeout should be triggered.
*/
#define J1939_XTP_ABORT_TIMEOUT_MS 500
#define J1939_SIMPLE_ECHO_TIMEOUT_MS (10 * 1000)
struct j1939_session;
enum j1939_sk_errqueue_type {
J1939_ERRQUEUE_ACK,
J1939_ERRQUEUE_SCHED,
J1939_ERRQUEUE_ABORT,
};
/* j1939 devices */
struct j1939_ecu {
struct list_head list;
name_t name;
u8 addr;
/* indicates that this ecu successfully claimed @sa as its address */
struct hrtimer ac_timer;
struct kref kref;
struct j1939_priv *priv;
/* count users, to help transport protocol decide for interaction */
int nusers;
};
struct j1939_priv {
struct list_head ecus;
/* local list entry in priv
* These allow irq (& softirq) context lookups on j1939 devices
* This approach (separate lists) is done as the other 2 alternatives
* are not easier or even wrong
* 1) using the pure kobject methods involves mutexes, which are not
* allowed in irq context.
* 2) duplicating data structures would require a lot of synchronization
* code
* usage:
*/
/* segments need a lock to protect the above list */
rwlock_t lock;
struct net_device *ndev;
/* list of 256 ecu ptrs, that cache the claimed addresses.
* also protected by the above lock
*/
struct j1939_addr_ent {
struct j1939_ecu *ecu;
/* count users, to help transport protocol */
int nusers;
} ents[256];
struct kref kref;
/* List of active sessions to prevent start of conflicting
* one.
*
* Do not start two sessions of same type, addresses and
* direction.
*/
struct list_head active_session_list;
/* protects active_session_list */
spinlock_t active_session_list_lock;
unsigned int tp_max_packet_size;
/* lock for j1939_socks list */
spinlock_t j1939_socks_lock;
struct list_head j1939_socks;
struct kref rx_kref;
};
void j1939_ecu_put(struct j1939_ecu *ecu);
/* keep the cache of what is local */
int j1939_local_ecu_get(struct j1939_priv *priv, name_t name, u8 sa);
void j1939_local_ecu_put(struct j1939_priv *priv, name_t name, u8 sa);
static inline bool j1939_address_is_unicast(u8 addr)
{
return addr <= J1939_MAX_UNICAST_ADDR;
}
static inline bool j1939_address_is_idle(u8 addr)
{
return addr == J1939_IDLE_ADDR;
}
static inline bool j1939_address_is_valid(u8 addr)
{
return addr != J1939_NO_ADDR;
}
static inline bool j1939_pgn_is_pdu1(pgn_t pgn)
{
/* ignore dp & res bits for this */
return (pgn & 0xff00) < 0xf000;
}
/* utility to correctly unmap an ECU */
void j1939_ecu_unmap_locked(struct j1939_ecu *ecu);
void j1939_ecu_unmap(struct j1939_ecu *ecu);
u8 j1939_name_to_addr(struct j1939_priv *priv, name_t name);
struct j1939_ecu *j1939_ecu_find_by_addr_locked(struct j1939_priv *priv,
u8 addr);
struct j1939_ecu *j1939_ecu_get_by_addr(struct j1939_priv *priv, u8 addr);
struct j1939_ecu *j1939_ecu_get_by_addr_locked(struct j1939_priv *priv,
u8 addr);
struct j1939_ecu *j1939_ecu_get_by_name(struct j1939_priv *priv, name_t name);
struct j1939_ecu *j1939_ecu_get_by_name_locked(struct j1939_priv *priv,
name_t name);
enum j1939_transfer_type {
J1939_TP,
J1939_ETP,
J1939_SIMPLE,
};
struct j1939_addr {
name_t src_name;
name_t dst_name;
pgn_t pgn;
u8 sa;
u8 da;
u8 type;
};
/* control buffer of the sk_buff */
struct j1939_sk_buff_cb {
/* Offset in bytes within one ETP session */
u32 offset;
/* for tx, MSG_SYN will be used to sync on sockets */
u32 msg_flags;
u32 tskey;
struct j1939_addr addr;
/* Flags for quick lookups during skb processing.
* These are set in the receive path only.
*/
#define J1939_ECU_LOCAL_SRC BIT(0)
#define J1939_ECU_LOCAL_DST BIT(1)
u8 flags;
priority_t priority;
};
static inline
struct j1939_sk_buff_cb *j1939_skb_to_cb(const struct sk_buff *skb)
{
BUILD_BUG_ON(sizeof(struct j1939_sk_buff_cb) > sizeof(skb->cb));
return (struct j1939_sk_buff_cb *)skb->cb;
}
int j1939_send_one(struct j1939_priv *priv, struct sk_buff *skb);
void j1939_sk_recv(struct j1939_priv *priv, struct sk_buff *skb);
bool j1939_sk_recv_match(struct j1939_priv *priv,
struct j1939_sk_buff_cb *skcb);
void j1939_sk_send_loop_abort(struct sock *sk, int err);
void j1939_sk_errqueue(struct j1939_session *session,
enum j1939_sk_errqueue_type type);
void j1939_sk_queue_activate_next(struct j1939_session *session);
/* stack entries */
struct j1939_session *j1939_tp_send(struct j1939_priv *priv,
struct sk_buff *skb, size_t size);
int j1939_tp_recv(struct j1939_priv *priv, struct sk_buff *skb);
int j1939_ac_fixup(struct j1939_priv *priv, struct sk_buff *skb);
void j1939_ac_recv(struct j1939_priv *priv, struct sk_buff *skb);
void j1939_simple_recv(struct j1939_priv *priv, struct sk_buff *skb);
/* network management */
struct j1939_ecu *j1939_ecu_create_locked(struct j1939_priv *priv, name_t name);
void j1939_ecu_timer_start(struct j1939_ecu *ecu);
void j1939_ecu_timer_cancel(struct j1939_ecu *ecu);
void j1939_ecu_unmap_all(struct j1939_priv *priv);
struct j1939_priv *j1939_netdev_start(struct net_device *ndev);
void j1939_netdev_stop(struct j1939_priv *priv);
void j1939_priv_put(struct j1939_priv *priv);
void j1939_priv_get(struct j1939_priv *priv);
/* notify/alert all j1939 sockets bound to ifindex */
void j1939_sk_netdev_event_netdown(struct j1939_priv *priv);
int j1939_cancel_active_session(struct j1939_priv *priv, struct sock *sk);
void j1939_tp_init(struct j1939_priv *priv);
/* decrement pending skb for a j1939 socket */
void j1939_sock_pending_del(struct sock *sk);
enum j1939_session_state {
J1939_SESSION_NEW,
J1939_SESSION_ACTIVE,
/* waiting for abort signal on the bus */
J1939_SESSION_WAITING_ABORT,
J1939_SESSION_ACTIVE_MAX,
J1939_SESSION_DONE,
};
struct j1939_session {
struct j1939_priv *priv;
struct list_head active_session_list_entry;
struct list_head sk_session_queue_entry;
struct kref kref;
struct sock *sk;
/* ifindex, src, dst, pgn define the session block
* the are _never_ modified after insertion in the list
* this decreases locking problems a _lot_
*/
struct j1939_sk_buff_cb skcb;
struct sk_buff_head skb_queue;
/* all tx related stuff (last_txcmd, pkt.tx)
* is protected (modified only) with the txtimer hrtimer
* 'total' & 'block' are never changed,
* last_cmd, last & block are protected by ->lock
* this means that the tx may run after cts is received that should
* have stopped tx, but this time discrepancy is never avoided anyhow
*/
u8 last_cmd, last_txcmd;
bool transmission;
bool extd;
/* Total message size, number of bytes */
unsigned int total_message_size;
/* Total number of bytes queue from socket to the session */
unsigned int total_queued_size;
unsigned int tx_retry;
int err;
u32 tskey;
enum j1939_session_state state;
/* Packets counters for a (extended) transfer session. The packet is
* maximal of 7 bytes.
*/
struct {
/* total - total number of packets for this session */
unsigned int total;
/* last - last packet of a transfer block after which
* responder should send ETP.CM_CTS and originator
* ETP.CM_DPO
*/
unsigned int last;
/* tx - number of packets send by originator node.
* this counter can be set back if responder node
* didn't received all packets send by originator.
*/
unsigned int tx;
unsigned int tx_acked;
/* rx - number of packets received */
unsigned int rx;
/* block - amount of packets expected in one block */
unsigned int block;
/* dpo - ETP.CM_DPO, Data Packet Offset */
unsigned int dpo;
} pkt;
struct hrtimer txtimer, rxtimer;
};
struct j1939_sock {
struct sock sk; /* must be first to skip with memset */
struct j1939_priv *priv;
struct list_head list;
#define J1939_SOCK_BOUND BIT(0)
#define J1939_SOCK_CONNECTED BIT(1)
#define J1939_SOCK_PROMISC BIT(2)
#define J1939_SOCK_ERRQUEUE BIT(3)
int state;
int ifindex;
struct j1939_addr addr;
struct j1939_filter *filters;
int nfilters;
pgn_t pgn_rx_filter;
/* j1939 may emit equal PGN (!= equal CAN-id's) out of order
* when transport protocol comes in.
* To allow emitting in order, keep a 'pending' nr. of packets
*/
atomic_t skb_pending;
wait_queue_head_t waitq;
/* lock for the sk_session_queue list */
spinlock_t sk_session_queue_lock;
struct list_head sk_session_queue;
};
static inline struct j1939_sock *j1939_sk(const struct sock *sk)
{
return container_of(sk, struct j1939_sock, sk);
}
void j1939_session_get(struct j1939_session *session);
void j1939_session_put(struct j1939_session *session);
void j1939_session_skb_queue(struct j1939_session *session,
struct sk_buff *skb);
int j1939_session_activate(struct j1939_session *session);
void j1939_tp_schedule_txtimer(struct j1939_session *session, int msec);
void j1939_session_timers_cancel(struct j1939_session *session);
#define J1939_MAX_TP_PACKET_SIZE (7 * 0xff)
#define J1939_MAX_ETP_PACKET_SIZE (7 * 0x00ffffff)
#define J1939_REGULAR 0
#define J1939_EXTENDED 1
/* CAN protocol */
extern const struct can_proto j1939_can_proto;
#endif /* _J1939_PRIV_H_ */

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net/can/j1939/main.c Normal file
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// SPDX-License-Identifier: GPL-2.0
// Copyright (c) 2010-2011 EIA Electronics,
// Pieter Beyens <pieter.beyens@eia.be>
// Copyright (c) 2010-2011 EIA Electronics,
// Kurt Van Dijck <kurt.van.dijck@eia.be>
// Copyright (c) 2018 Protonic,
// Robin van der Gracht <robin@protonic.nl>
// Copyright (c) 2017-2019 Pengutronix,
// Marc Kleine-Budde <kernel@pengutronix.de>
// Copyright (c) 2017-2019 Pengutronix,
// Oleksij Rempel <kernel@pengutronix.de>
/* Core of can-j1939 that links j1939 to CAN. */
#include <linux/can/can-ml.h>
#include <linux/can/core.h>
#include <linux/can/skb.h>
#include <linux/if_arp.h>
#include <linux/module.h>
#include "j1939-priv.h"
MODULE_DESCRIPTION("PF_CAN SAE J1939");
MODULE_LICENSE("GPL v2");
MODULE_AUTHOR("EIA Electronics (Kurt Van Dijck & Pieter Beyens)");
MODULE_ALIAS("can-proto-" __stringify(CAN_J1939));
/* LOWLEVEL CAN interface */
/* CAN_HDR: #bytes before can_frame data part */
#define J1939_CAN_HDR (offsetof(struct can_frame, data))
/* CAN_FTR: #bytes beyond data part */
#define J1939_CAN_FTR (sizeof(struct can_frame) - J1939_CAN_HDR - \
sizeof(((struct can_frame *)0)->data))
/* lowest layer */
static void j1939_can_recv(struct sk_buff *iskb, void *data)
{
struct j1939_priv *priv = data;
struct sk_buff *skb;
struct j1939_sk_buff_cb *skcb, *iskcb;
struct can_frame *cf;
/* create a copy of the skb
* j1939 only delivers the real data bytes,
* the header goes into sockaddr.
* j1939 may not touch the incoming skb in such way
*/
skb = skb_clone(iskb, GFP_ATOMIC);
if (!skb)
return;
can_skb_set_owner(skb, iskb->sk);
/* get a pointer to the header of the skb
* the skb payload (pointer) is moved, so that the next skb_data
* returns the actual payload
*/
cf = (void *)skb->data;
skb_pull(skb, J1939_CAN_HDR);
/* fix length, set to dlc, with 8 maximum */
skb_trim(skb, min_t(uint8_t, cf->can_dlc, 8));
/* set addr */
skcb = j1939_skb_to_cb(skb);
memset(skcb, 0, sizeof(*skcb));
iskcb = j1939_skb_to_cb(iskb);
skcb->tskey = iskcb->tskey;
skcb->priority = (cf->can_id >> 26) & 0x7;
skcb->addr.sa = cf->can_id;
skcb->addr.pgn = (cf->can_id >> 8) & J1939_PGN_MAX;
/* set default message type */
skcb->addr.type = J1939_TP;
if (j1939_pgn_is_pdu1(skcb->addr.pgn)) {
/* Type 1: with destination address */
skcb->addr.da = skcb->addr.pgn;
/* normalize pgn: strip dst address */
skcb->addr.pgn &= 0x3ff00;
} else {
/* set broadcast address */
skcb->addr.da = J1939_NO_ADDR;
}
/* update localflags */
read_lock_bh(&priv->lock);
if (j1939_address_is_unicast(skcb->addr.sa) &&
priv->ents[skcb->addr.sa].nusers)
skcb->flags |= J1939_ECU_LOCAL_SRC;
if (j1939_address_is_unicast(skcb->addr.da) &&
priv->ents[skcb->addr.da].nusers)
skcb->flags |= J1939_ECU_LOCAL_DST;
read_unlock_bh(&priv->lock);
/* deliver into the j1939 stack ... */
j1939_ac_recv(priv, skb);
if (j1939_tp_recv(priv, skb))
/* this means the transport layer processed the message */
goto done;
j1939_simple_recv(priv, skb);
j1939_sk_recv(priv, skb);
done:
kfree_skb(skb);
}
/* NETDEV MANAGEMENT */
/* values for can_rx_(un)register */
#define J1939_CAN_ID CAN_EFF_FLAG
#define J1939_CAN_MASK (CAN_EFF_FLAG | CAN_RTR_FLAG)
static DEFINE_SPINLOCK(j1939_netdev_lock);
static struct j1939_priv *j1939_priv_create(struct net_device *ndev)
{
struct j1939_priv *priv;
priv = kzalloc(sizeof(*priv), GFP_KERNEL);
if (!priv)
return NULL;
rwlock_init(&priv->lock);
INIT_LIST_HEAD(&priv->ecus);
priv->ndev = ndev;
kref_init(&priv->kref);
kref_init(&priv->rx_kref);
dev_hold(ndev);
netdev_dbg(priv->ndev, "%s : 0x%p\n", __func__, priv);
return priv;
}
static inline void j1939_priv_set(struct net_device *ndev,
struct j1939_priv *priv)
{
struct can_ml_priv *can_ml_priv = ndev->ml_priv;
can_ml_priv->j1939_priv = priv;
}
static void __j1939_priv_release(struct kref *kref)
{
struct j1939_priv *priv = container_of(kref, struct j1939_priv, kref);
struct net_device *ndev = priv->ndev;
netdev_dbg(priv->ndev, "%s: 0x%p\n", __func__, priv);
dev_put(ndev);
kfree(priv);
}
void j1939_priv_put(struct j1939_priv *priv)
{
kref_put(&priv->kref, __j1939_priv_release);
}
void j1939_priv_get(struct j1939_priv *priv)
{
kref_get(&priv->kref);
}
static int j1939_can_rx_register(struct j1939_priv *priv)
{
struct net_device *ndev = priv->ndev;
int ret;
j1939_priv_get(priv);
ret = can_rx_register(dev_net(ndev), ndev, J1939_CAN_ID, J1939_CAN_MASK,
j1939_can_recv, priv, "j1939", NULL);
if (ret < 0) {
j1939_priv_put(priv);
return ret;
}
return 0;
}
static void j1939_can_rx_unregister(struct j1939_priv *priv)
{
struct net_device *ndev = priv->ndev;
can_rx_unregister(dev_net(ndev), ndev, J1939_CAN_ID, J1939_CAN_MASK,
j1939_can_recv, priv);
j1939_priv_put(priv);
}
static void __j1939_rx_release(struct kref *kref)
__releases(&j1939_netdev_lock)
{
struct j1939_priv *priv = container_of(kref, struct j1939_priv,
rx_kref);
j1939_can_rx_unregister(priv);
j1939_ecu_unmap_all(priv);
j1939_priv_set(priv->ndev, NULL);
spin_unlock(&j1939_netdev_lock);
}
/* get pointer to priv without increasing ref counter */
static inline struct j1939_priv *j1939_ndev_to_priv(struct net_device *ndev)
{
struct can_ml_priv *can_ml_priv = ndev->ml_priv;
return can_ml_priv->j1939_priv;
}
static struct j1939_priv *j1939_priv_get_by_ndev_locked(struct net_device *ndev)
{
struct j1939_priv *priv;
lockdep_assert_held(&j1939_netdev_lock);
if (ndev->type != ARPHRD_CAN)
return NULL;
priv = j1939_ndev_to_priv(ndev);
if (priv)
j1939_priv_get(priv);
return priv;
}
static struct j1939_priv *j1939_priv_get_by_ndev(struct net_device *ndev)
{
struct j1939_priv *priv;
spin_lock(&j1939_netdev_lock);
priv = j1939_priv_get_by_ndev_locked(ndev);
spin_unlock(&j1939_netdev_lock);
return priv;
}
struct j1939_priv *j1939_netdev_start(struct net_device *ndev)
{
struct j1939_priv *priv, *priv_new;
int ret;
priv = j1939_priv_get_by_ndev(ndev);
if (priv) {
kref_get(&priv->rx_kref);
return priv;
}
priv = j1939_priv_create(ndev);
if (!priv)
return ERR_PTR(-ENOMEM);
j1939_tp_init(priv);
spin_lock_init(&priv->j1939_socks_lock);
INIT_LIST_HEAD(&priv->j1939_socks);
spin_lock(&j1939_netdev_lock);
priv_new = j1939_priv_get_by_ndev_locked(ndev);
if (priv_new) {
/* Someone was faster than us, use their priv and roll
* back our's.
*/
spin_unlock(&j1939_netdev_lock);
dev_put(ndev);
kfree(priv);
kref_get(&priv_new->rx_kref);
return priv_new;
}
j1939_priv_set(ndev, priv);
spin_unlock(&j1939_netdev_lock);
ret = j1939_can_rx_register(priv);
if (ret < 0)
goto out_priv_put;
return priv;
out_priv_put:
j1939_priv_set(ndev, NULL);
dev_put(ndev);
kfree(priv);
return ERR_PTR(ret);
}
void j1939_netdev_stop(struct j1939_priv *priv)
{
kref_put_lock(&priv->rx_kref, __j1939_rx_release, &j1939_netdev_lock);
j1939_priv_put(priv);
}
int j1939_send_one(struct j1939_priv *priv, struct sk_buff *skb)
{
int ret, dlc;
canid_t canid;
struct j1939_sk_buff_cb *skcb = j1939_skb_to_cb(skb);
struct can_frame *cf;
/* apply sanity checks */
if (j1939_pgn_is_pdu1(skcb->addr.pgn))
skcb->addr.pgn &= J1939_PGN_PDU1_MAX;
else
skcb->addr.pgn &= J1939_PGN_MAX;
if (skcb->priority > 7)
skcb->priority = 6;
ret = j1939_ac_fixup(priv, skb);
if (unlikely(ret))
goto failed;
dlc = skb->len;
/* re-claim the CAN_HDR from the SKB */
cf = skb_push(skb, J1939_CAN_HDR);
/* make it a full can frame again */
skb_put(skb, J1939_CAN_FTR + (8 - dlc));
canid = CAN_EFF_FLAG |
(skcb->priority << 26) |
(skcb->addr.pgn << 8) |
skcb->addr.sa;
if (j1939_pgn_is_pdu1(skcb->addr.pgn))
canid |= skcb->addr.da << 8;
cf->can_id = canid;
cf->can_dlc = dlc;
return can_send(skb, 1);
failed:
kfree_skb(skb);
return ret;
}
static int j1939_netdev_notify(struct notifier_block *nb,
unsigned long msg, void *data)
{
struct net_device *ndev = netdev_notifier_info_to_dev(data);
struct j1939_priv *priv;
priv = j1939_priv_get_by_ndev(ndev);
if (!priv)
goto notify_done;
if (ndev->type != ARPHRD_CAN)
goto notify_put;
switch (msg) {
case NETDEV_DOWN:
j1939_cancel_active_session(priv, NULL);
j1939_sk_netdev_event_netdown(priv);
j1939_ecu_unmap_all(priv);
break;
}
notify_put:
j1939_priv_put(priv);
notify_done:
return NOTIFY_DONE;
}
static struct notifier_block j1939_netdev_notifier = {
.notifier_call = j1939_netdev_notify,
};
/* MODULE interface */
static __init int j1939_module_init(void)
{
int ret;
pr_info("can: SAE J1939\n");
ret = register_netdevice_notifier(&j1939_netdev_notifier);
if (ret)
goto fail_notifier;
ret = can_proto_register(&j1939_can_proto);
if (ret < 0) {
pr_err("can: registration of j1939 protocol failed\n");
goto fail_sk;
}
return 0;
fail_sk:
unregister_netdevice_notifier(&j1939_netdev_notifier);
fail_notifier:
return ret;
}
static __exit void j1939_module_exit(void)
{
can_proto_unregister(&j1939_can_proto);
unregister_netdevice_notifier(&j1939_netdev_notifier);
}
module_init(j1939_module_init);
module_exit(j1939_module_exit);

1160
net/can/j1939/socket.c Normal file
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2027
net/can/j1939/transport.c Normal file
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