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Date: Thu, 01 Sep 2011 16:23:23 +0200
From: Oliver Hartkopp <socketcan@...tkopp.net>
To: David Miller <davem@...emloft.net>
CC: Linux Netdev List <netdev@...r.kernel.org>,
Michal Sojka <sojkam1@....cvut.cz>,
Pavel Píša <pisa@....felk.cvut.cz>,
Zdenek Hanzálek <hanzalek@....cvut.cz>,
Oliver Hartkopp <oliver.hartkopp@...kswagen.de>
Subject: [PATCH net-next] can-gw: add netlink based CAN routing
This patch adds a CAN Gateway/Router to route (and modify) CAN frames.
It is based on the PF_CAN core infrastructure for msg filtering and msg
sending and can optionally modify routed CAN frames on the fly.
CAN frames can *only* be routed between CAN network interfaces (one hop).
They can be modified with AND/OR/XOR/SET operations as configured by the
netlink configuration interface known e.g. from iptables. From the netlink
view this can-gw implements RTM_{NEW|DEL|GET}ROUTE for PF_CAN.
The CAN specific userspace tool to manage CAN routing entries can be found in
the CAN utils http://svn.berlios.de/wsvn/socketcan/trunk/can-utils/cangw.c
at the SocketCAN SVN on BerliOS.
Signed-off-by: Oliver Hartkopp <socketcan@...tkopp.net>
---
The in-kernel CAN frame routing has been implemented to due performance
issues and has turned out to be a valuable tool in multiple projects.
It relies on the networking stack and uses the efficient PF_CAN CAN filters.
It has been analyzed and checked against -rt kernels by University of Prague
(DCE), where a real good performace of this approach could be shown. Only
with heavy ethernet load the routing times increased - but that's networking.
See at http://rtime.felk.cvut.cz/can/benchmark/1/ and .../benchmark/2/
Special thanks for review, feedback, bug-reports & measurements to Michal
Sojka, Pavel Píša and Zdenek Hanzálek from department of control engineering.
include/linux/can/Kbuild | 1
include/linux/can/gw.h | 164 ++++++
net/can/Kconfig | 11
net/can/Makefile | 3
net/can/gw.c | 959 +++++++++++++++++++++++++++++++++++++
5 files changed, 1138 insertions(+)
diff -u -r -N a/include/linux/can/gw.h b/include/linux/can/gw.h
--- a/include/linux/can/gw.h 1970-01-01 01:00:00.000000000 +0100
+++ b/include/linux/can/gw.h 2011-09-01 11:33:47.966271223 +0200
@@ -0,0 +1,164 @@
+/*
+ * linux/can/gw.h
+ *
+ * Definitions for CAN frame Gateway/Router/Bridge
+ *
+ * Author: Oliver Hartkopp <oliver.hartkopp@...kswagen.de>
+ * Copyright (c) 2011 Volkswagen Group Electronic Research
+ * All rights reserved.
+ *
+ * Send feedback to <socketcan-users@...ts.berlios.de>
+ *
+ */
+
+#ifndef CAN_GW_H
+#define CAN_GW_H
+
+#include <linux/types.h>
+#include <linux/can.h>
+
+struct rtcanmsg {
+ __u8 can_family;
+ __u8 gwtype;
+ __u16 flags;
+};
+
+/* CAN gateway types */
+enum {
+ CGW_TYPE_UNSPEC,
+ CGW_TYPE_CAN_CAN, /* CAN->CAN routing */
+ __CGW_TYPE_MAX
+};
+
+#define CGW_TYPE_MAX (__CGW_TYPE_MAX - 1)
+
+/* CAN rtnetlink attribute definitions */
+enum {
+ CGW_UNSPEC,
+ CGW_MOD_AND, /* CAN frame modification binary AND */
+ CGW_MOD_OR, /* CAN frame modification binary OR */
+ CGW_MOD_XOR, /* CAN frame modification binary XOR */
+ CGW_MOD_SET, /* CAN frame modification set alternate values */
+ CGW_CS_XOR, /* set data[] XOR checksum into data[index] */
+ CGW_CS_CRC8, /* set data[] CRC8 checksum into data[index] */
+ CGW_HANDLED, /* number of handled CAN frames */
+ CGW_DROPPED, /* number of dropped CAN frames */
+ CGW_SRC_IF, /* ifindex of source network interface */
+ CGW_DST_IF, /* ifindex of destination network interface */
+ CGW_FILTER, /* specify struct can_filter on source CAN device */
+ __CGW_MAX
+};
+
+#define CGW_MAX (__CGW_MAX - 1)
+
+#define CGW_FLAGS_CAN_ECHO 0x01
+#define CGW_FLAGS_CAN_SRC_TSTAMP 0x02
+
+#define CGW_MOD_FUNCS 4 /* AND OR XOR SET */
+
+/* CAN frame elements that are affected by curr. 3 CAN frame modifications */
+#define CGW_MOD_ID 0x01
+#define CGW_MOD_DLC 0x02
+#define CGW_MOD_DATA 0x04
+
+#define CGW_FRAME_MODS 3 /* ID DLC DATA */
+
+#define MAX_MODFUNCTIONS (CGW_MOD_FUNCS * CGW_FRAME_MODS)
+
+struct cgw_frame_mod {
+ struct can_frame cf;
+ __u8 modtype;
+} __attribute__((packed));
+
+#define CGW_MODATTR_LEN sizeof(struct cgw_frame_mod)
+
+struct cgw_csum_xor {
+ __s8 from_idx;
+ __s8 to_idx;
+ __s8 result_idx;
+ __u8 init_xor_val;
+} __attribute__((packed));
+
+struct cgw_csum_crc8 {
+ __s8 from_idx;
+ __s8 to_idx;
+ __s8 result_idx;
+ __u8 init_crc_val;
+ __u8 final_xor_val;
+ __u8 crctab[256];
+ __u8 profile;
+ __u8 profile_data[20];
+} __attribute__((packed));
+
+/* length of checksum operation parameters. idx = index in CAN frame data[] */
+#define CGW_CS_XOR_LEN sizeof(struct cgw_csum_xor)
+#define CGW_CS_CRC8_LEN sizeof(struct cgw_csum_crc8)
+
+/* CRC8 profiles (compute CRC for additional data elements - see below) */
+enum {
+ CGW_CRC8PRF_UNSPEC,
+ CGW_CRC8PRF_1U8, /* compute one additional u8 value */
+ CGW_CRC8PRF_16U8, /* u8 value table indexed by data[1] & 0xF */
+ CGW_CRC8PRF_SFFID_XOR, /* (can_id & 0xFF) ^ (can_id >> 8 & 0xFF) */
+ __CGW_CRC8PRF_MAX
+};
+
+#define CGW_CRC8PRF_MAX (__CGW_CRC8PRF_MAX - 1)
+
+/*
+ * CAN rtnetlink attribute contents in detail
+ *
+ * CGW_XXX_IF (length 4 bytes):
+ * Sets an interface index for source/destination network interfaces.
+ * For the CAN->CAN gwtype the indices of _two_ CAN interfaces are mandatory.
+ *
+ * CGW_FILTER (length 8 bytes):
+ * Sets a CAN receive filter for the gateway job specified by the
+ * struct can_filter described in include/linux/can.h
+ *
+ * CGW_MOD_XXX (length 17 bytes):
+ * Specifies a modification that's done to a received CAN frame before it is
+ * send out to the destination interface.
+ *
+ * <struct can_frame> data used as operator
+ * <u8> affected CAN frame elements
+ *
+ * CGW_CS_XOR (length 4 bytes):
+ * Set a simple XOR checksum starting with an initial value into
+ * data[result-idx] using data[start-idx] .. data[end-idx]
+ *
+ * The XOR checksum is calculated like this:
+ *
+ * xor = init_xor_val
+ *
+ * for (i = from_idx .. to_idx)
+ * xor ^= can_frame.data[i]
+ *
+ * can_frame.data[ result_idx ] = xor
+ *
+ * CGW_CS_CRC8 (length 282 bytes):
+ * Set a CRC8 value into data[result-idx] using a given 256 byte CRC8 table,
+ * a given initial value and a defined input data[start-idx] .. data[end-idx].
+ * Finally the result value is XOR'ed with the final_xor_val.
+ *
+ * The CRC8 checksum is calculated like this:
+ *
+ * crc = init_crc_val
+ *
+ * for (i = from_idx .. to_idx)
+ * crc = crctab[ crc ^ can_frame.data[i] ]
+ *
+ * can_frame.data[ result_idx ] = crc ^ final_xor_val
+ *
+ * The calculated CRC may contain additional source data elements that can be
+ * defined in the handling of 'checksum profiles' e.g. shown in AUTOSAR specs
+ * like http://www.autosar.org/download/R4.0/AUTOSAR_SWS_E2ELibrary.pdf
+ * E.g. the profile_data[] may contain additional u8 values (called DATA_IDs)
+ * that are used depending on counter values inside the CAN frame data[].
+ * So far only three profiles have been implemented for illustration.
+ *
+ * Remark: In general the attribute data is a linear buffer.
+ * Beware of sending unpacked or aligned structs!
+ */
+
+#endif
diff -u -r -N a/include/linux/can/Kbuild b/include/linux/can/Kbuild
--- a/include/linux/can/Kbuild 2011-08-31 21:28:47.515610142 +0200
+++ b/include/linux/can/Kbuild 2011-08-31 21:29:24.343608873 +0200
@@ -1,4 +1,5 @@
header-y += raw.h
header-y += bcm.h
+header-y += gw.h
header-y += error.h
header-y += netlink.h
diff -u -r -N a/net/can/gw.c b/net/can/gw.c
--- a/net/can/gw.c 1970-01-01 01:00:00.000000000 +0100
+++ b/net/can/gw.c 2011-09-01 11:26:56.898284721 +0200
@@ -0,0 +1,959 @@
+/*
+ * gw.c - CAN frame Gateway/Router/Bridge with netlink interface
+ *
+ * Copyright (c) 2011 Volkswagen Group Electronic Research
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of Volkswagen nor the names of its contributors
+ * may be used to endorse or promote products derived from this software
+ * without specific prior written permission.
+ *
+ * Alternatively, provided that this notice is retained in full, this
+ * software may be distributed under the terms of the GNU General
+ * Public License ("GPL") version 2, in which case the provisions of the
+ * GPL apply INSTEAD OF those given above.
+ *
+ * The provided data structures and external interfaces from this code
+ * are not restricted to be used by modules with a GPL compatible license.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
+ * DAMAGE.
+ *
+ * Send feedback to <socketcan-users@...ts.berlios.de>
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/types.h>
+#include <linux/list.h>
+#include <linux/spinlock.h>
+#include <linux/rcupdate.h>
+#include <linux/rculist.h>
+#include <linux/net.h>
+#include <linux/netdevice.h>
+#include <linux/if_arp.h>
+#include <linux/skbuff.h>
+#include <linux/can.h>
+#include <linux/can/core.h>
+#include <linux/can/gw.h>
+#include <net/rtnetlink.h>
+#include <net/net_namespace.h>
+#include <net/sock.h>
+
+#define CAN_GW_VERSION "20101209"
+static __initdata const char banner[] =
+ KERN_INFO "can: netlink gateway (rev " CAN_GW_VERSION ")\n";
+
+MODULE_DESCRIPTION("PF_CAN netlink gateway");
+MODULE_LICENSE("Dual BSD/GPL");
+MODULE_AUTHOR("Oliver Hartkopp <oliver.hartkopp@...kswagen.de>");
+MODULE_ALIAS("can-gw");
+
+HLIST_HEAD(cgw_list);
+static struct notifier_block notifier;
+
+static struct kmem_cache *cgw_cache __read_mostly;
+
+/* structure that contains the (on-the-fly) CAN frame modifications */
+struct cf_mod {
+ struct {
+ struct can_frame and;
+ struct can_frame or;
+ struct can_frame xor;
+ struct can_frame set;
+ } modframe;
+ struct {
+ u8 and;
+ u8 or;
+ u8 xor;
+ u8 set;
+ } modtype;
+ void (*modfunc[MAX_MODFUNCTIONS])(struct can_frame *cf,
+ struct cf_mod *mod);
+
+ /* CAN frame checksum calculation after CAN frame modifications */
+ struct {
+ struct cgw_csum_xor xor;
+ struct cgw_csum_crc8 crc8;
+ } csum;
+ struct {
+ void (*xor)(struct can_frame *cf, struct cgw_csum_xor *xor);
+ void (*crc8)(struct can_frame *cf, struct cgw_csum_crc8 *crc8);
+ } csumfunc;
+};
+
+
+/*
+ * So far we just support CAN -> CAN routing and frame modifications.
+ *
+ * The internal can_can_gw structure contains data and attributes for
+ * a CAN -> CAN gateway job.
+ */
+struct can_can_gw {
+ struct can_filter filter;
+ int src_idx;
+ int dst_idx;
+};
+
+/* list entry for CAN gateways jobs */
+struct cgw_job {
+ struct hlist_node list;
+ struct rcu_head rcu;
+ u32 handled_frames;
+ u32 dropped_frames;
+ struct cf_mod mod;
+ union {
+ /* CAN frame data source */
+ struct net_device *dev;
+ } src;
+ union {
+ /* CAN frame data destination */
+ struct net_device *dev;
+ } dst;
+ union {
+ struct can_can_gw ccgw;
+ /* tbc */
+ };
+ u8 gwtype;
+ u16 flags;
+};
+
+/* modification functions that are invoked in the hot path in can_can_gw_rcv */
+
+#define MODFUNC(func, op) static void func(struct can_frame *cf, \
+ struct cf_mod *mod) { op ; }
+
+MODFUNC(mod_and_id, cf->can_id &= mod->modframe.and.can_id)
+MODFUNC(mod_and_dlc, cf->can_dlc &= mod->modframe.and.can_dlc)
+MODFUNC(mod_and_data, *(u64 *)cf->data &= *(u64 *)mod->modframe.and.data)
+MODFUNC(mod_or_id, cf->can_id |= mod->modframe.or.can_id)
+MODFUNC(mod_or_dlc, cf->can_dlc |= mod->modframe.or.can_dlc)
+MODFUNC(mod_or_data, *(u64 *)cf->data |= *(u64 *)mod->modframe.or.data)
+MODFUNC(mod_xor_id, cf->can_id ^= mod->modframe.xor.can_id)
+MODFUNC(mod_xor_dlc, cf->can_dlc ^= mod->modframe.xor.can_dlc)
+MODFUNC(mod_xor_data, *(u64 *)cf->data ^= *(u64 *)mod->modframe.xor.data)
+MODFUNC(mod_set_id, cf->can_id = mod->modframe.set.can_id)
+MODFUNC(mod_set_dlc, cf->can_dlc = mod->modframe.set.can_dlc)
+MODFUNC(mod_set_data, *(u64 *)cf->data = *(u64 *)mod->modframe.set.data)
+
+static inline void canframecpy(struct can_frame *dst, struct can_frame *src)
+{
+ /*
+ * Copy the struct members separately to ensure that no uninitialized
+ * data are copied in the 3 bytes hole of the struct. This is needed
+ * to make easy compares of the data in the struct cf_mod.
+ */
+
+ dst->can_id = src->can_id;
+ dst->can_dlc = src->can_dlc;
+ *(u64 *)dst->data = *(u64 *)src->data;
+}
+
+static int cgw_chk_csum_parms(s8 fr, s8 to, s8 re)
+{
+ /*
+ * absolute dlc values 0 .. 7 => 0 .. 7, e.g. data [0]
+ * relative to received dlc -1 .. -8 :
+ * e.g. for received dlc = 8
+ * -1 => index = 7 (data[7])
+ * -3 => index = 5 (data[5])
+ * -8 => index = 0 (data[0])
+ */
+
+ if (fr > -9 && fr < 8 &&
+ to > -9 && to < 8 &&
+ re > -9 && re < 8)
+ return 0;
+ else
+ return -EINVAL;
+}
+
+static inline int calc_idx(int idx, int rx_dlc)
+{
+ if (idx < 0)
+ return rx_dlc + idx;
+ else
+ return idx;
+}
+
+static void cgw_csum_xor_rel(struct can_frame *cf, struct cgw_csum_xor *xor)
+{
+ int from = calc_idx(xor->from_idx, cf->can_dlc);
+ int to = calc_idx(xor->to_idx, cf->can_dlc);
+ int res = calc_idx(xor->result_idx, cf->can_dlc);
+ u8 val = xor->init_xor_val;
+ int i;
+
+ if (from < 0 || to < 0 || res < 0)
+ return;
+
+ if (from <= to) {
+ for (i = from; i <= to; i++)
+ val ^= cf->data[i];
+ } else {
+ for (i = from; i >= to; i--)
+ val ^= cf->data[i];
+ }
+
+ cf->data[res] = val;
+}
+
+static void cgw_csum_xor_pos(struct can_frame *cf, struct cgw_csum_xor *xor)
+{
+ u8 val = xor->init_xor_val;
+ int i;
+
+ for (i = xor->from_idx; i <= xor->to_idx; i++)
+ val ^= cf->data[i];
+
+ cf->data[xor->result_idx] = val;
+}
+
+static void cgw_csum_xor_neg(struct can_frame *cf, struct cgw_csum_xor *xor)
+{
+ u8 val = xor->init_xor_val;
+ int i;
+
+ for (i = xor->from_idx; i >= xor->to_idx; i--)
+ val ^= cf->data[i];
+
+ cf->data[xor->result_idx] = val;
+}
+
+static void cgw_csum_crc8_rel(struct can_frame *cf, struct cgw_csum_crc8 *crc8)
+{
+ int from = calc_idx(crc8->from_idx, cf->can_dlc);
+ int to = calc_idx(crc8->to_idx, cf->can_dlc);
+ int res = calc_idx(crc8->result_idx, cf->can_dlc);
+ u8 crc = crc8->init_crc_val;
+ int i;
+
+ if (from < 0 || to < 0 || res < 0)
+ return;
+
+ if (from <= to) {
+ for (i = crc8->from_idx; i <= crc8->to_idx; i++)
+ crc = crc8->crctab[crc^cf->data[i]];
+ } else {
+ for (i = crc8->from_idx; i >= crc8->to_idx; i--)
+ crc = crc8->crctab[crc^cf->data[i]];
+ }
+
+ switch (crc8->profile) {
+
+ case CGW_CRC8PRF_1U8:
+ crc = crc8->crctab[crc^crc8->profile_data[0]];
+ break;
+
+ case CGW_CRC8PRF_16U8:
+ crc = crc8->crctab[crc^crc8->profile_data[cf->data[1] & 0xF]];
+ break;
+
+ case CGW_CRC8PRF_SFFID_XOR:
+ crc = crc8->crctab[crc^(cf->can_id & 0xFF)^
+ (cf->can_id >> 8 & 0xFF)];
+ break;
+
+ }
+
+ cf->data[crc8->result_idx] = crc^crc8->final_xor_val;
+}
+
+static void cgw_csum_crc8_pos(struct can_frame *cf, struct cgw_csum_crc8 *crc8)
+{
+ u8 crc = crc8->init_crc_val;
+ int i;
+
+ for (i = crc8->from_idx; i <= crc8->to_idx; i++)
+ crc = crc8->crctab[crc^cf->data[i]];
+
+ switch (crc8->profile) {
+
+ case CGW_CRC8PRF_1U8:
+ crc = crc8->crctab[crc^crc8->profile_data[0]];
+ break;
+
+ case CGW_CRC8PRF_16U8:
+ crc = crc8->crctab[crc^crc8->profile_data[cf->data[1] & 0xF]];
+ break;
+
+ case CGW_CRC8PRF_SFFID_XOR:
+ crc = crc8->crctab[crc^(cf->can_id & 0xFF)^
+ (cf->can_id >> 8 & 0xFF)];
+ break;
+ }
+
+ cf->data[crc8->result_idx] = crc^crc8->final_xor_val;
+}
+
+static void cgw_csum_crc8_neg(struct can_frame *cf, struct cgw_csum_crc8 *crc8)
+{
+ u8 crc = crc8->init_crc_val;
+ int i;
+
+ for (i = crc8->from_idx; i >= crc8->to_idx; i--)
+ crc = crc8->crctab[crc^cf->data[i]];
+
+ switch (crc8->profile) {
+
+ case CGW_CRC8PRF_1U8:
+ crc = crc8->crctab[crc^crc8->profile_data[0]];
+ break;
+
+ case CGW_CRC8PRF_16U8:
+ crc = crc8->crctab[crc^crc8->profile_data[cf->data[1] & 0xF]];
+ break;
+
+ case CGW_CRC8PRF_SFFID_XOR:
+ crc = crc8->crctab[crc^(cf->can_id & 0xFF)^
+ (cf->can_id >> 8 & 0xFF)];
+ break;
+ }
+
+ cf->data[crc8->result_idx] = crc^crc8->final_xor_val;
+}
+
+/* the receive & process & send function */
+static void can_can_gw_rcv(struct sk_buff *skb, void *data)
+{
+ struct cgw_job *gwj = (struct cgw_job *)data;
+ struct can_frame *cf;
+ struct sk_buff *nskb;
+ int modidx = 0;
+
+ /* do not handle already routed frames - see comment below */
+ if (skb_mac_header_was_set(skb))
+ return;
+
+ if (!(gwj->dst.dev->flags & IFF_UP)) {
+ gwj->dropped_frames++;
+ return;
+ }
+
+ /*
+ * clone the given skb, which has not been done in can_rcv()
+ *
+ * When there is at least one modification function activated,
+ * we need to copy the skb as we want to modify skb->data.
+ */
+ if (gwj->mod.modfunc[0])
+ nskb = skb_copy(skb, GFP_ATOMIC);
+ else
+ nskb = skb_clone(skb, GFP_ATOMIC);
+
+ if (!nskb) {
+ gwj->dropped_frames++;
+ return;
+ }
+
+ /*
+ * Mark routed frames by setting some mac header length which is
+ * not relevant for the CAN frames located in the skb->data section.
+ *
+ * As dev->header_ops is not set in CAN netdevices no one is ever
+ * accessing the various header offsets in the CAN skbuffs anyway.
+ * E.g. using the packet socket to read CAN frames is still working.
+ */
+ skb_set_mac_header(nskb, 8);
+ nskb->dev = gwj->dst.dev;
+
+ /* pointer to modifiable CAN frame */
+ cf = (struct can_frame *)nskb->data;
+
+ /* perform preprocessed modification functions if there are any */
+ while (modidx < MAX_MODFUNCTIONS && gwj->mod.modfunc[modidx])
+ (*gwj->mod.modfunc[modidx++])(cf, &gwj->mod);
+
+ /* check for checksum updates when the CAN frame has been modified */
+ if (modidx) {
+ if (gwj->mod.csumfunc.crc8)
+ (*gwj->mod.csumfunc.crc8)(cf, &gwj->mod.csum.crc8);
+
+ if (gwj->mod.csumfunc.xor)
+ (*gwj->mod.csumfunc.xor)(cf, &gwj->mod.csum.xor);
+ }
+
+ /* clear the skb timestamp if not configured the other way */
+ if (!(gwj->flags & CGW_FLAGS_CAN_SRC_TSTAMP))
+ nskb->tstamp.tv64 = 0;
+
+ /* send to netdevice */
+ if (can_send(nskb, gwj->flags & CGW_FLAGS_CAN_ECHO))
+ gwj->dropped_frames++;
+ else
+ gwj->handled_frames++;
+}
+
+static inline int cgw_register_filter(struct cgw_job *gwj)
+{
+ return can_rx_register(gwj->src.dev, gwj->ccgw.filter.can_id,
+ gwj->ccgw.filter.can_mask, can_can_gw_rcv,
+ gwj, "gw");
+}
+
+static inline void cgw_unregister_filter(struct cgw_job *gwj)
+{
+ can_rx_unregister(gwj->src.dev, gwj->ccgw.filter.can_id,
+ gwj->ccgw.filter.can_mask, can_can_gw_rcv, gwj);
+}
+
+static int cgw_notifier(struct notifier_block *nb,
+ unsigned long msg, void *data)
+{
+ struct net_device *dev = (struct net_device *)data;
+
+ if (!net_eq(dev_net(dev), &init_net))
+ return NOTIFY_DONE;
+ if (dev->type != ARPHRD_CAN)
+ return NOTIFY_DONE;
+
+ if (msg == NETDEV_UNREGISTER) {
+
+ struct cgw_job *gwj = NULL;
+ struct hlist_node *n, *nx;
+
+ ASSERT_RTNL();
+
+ hlist_for_each_entry_safe(gwj, n, nx, &cgw_list, list) {
+
+ if (gwj->src.dev == dev || gwj->dst.dev == dev) {
+ hlist_del(&gwj->list);
+ cgw_unregister_filter(gwj);
+ kfree(gwj);
+ }
+ }
+ }
+
+ return NOTIFY_DONE;
+}
+
+static int cgw_put_job(struct sk_buff *skb, struct cgw_job *gwj)
+{
+ struct cgw_frame_mod mb;
+ struct rtcanmsg *rtcan;
+ struct nlmsghdr *nlh = nlmsg_put(skb, 0, 0, 0, sizeof(*rtcan), 0);
+ if (!nlh)
+ return -EMSGSIZE;
+
+ rtcan = nlmsg_data(nlh);
+ rtcan->can_family = AF_CAN;
+ rtcan->gwtype = gwj->gwtype;
+ rtcan->flags = gwj->flags;
+
+ /* add statistics if available */
+
+ if (gwj->handled_frames) {
+ if (nla_put_u32(skb, CGW_HANDLED, gwj->handled_frames) < 0)
+ goto cancel;
+ else
+ nlh->nlmsg_len += NLA_HDRLEN + NLA_ALIGN(sizeof(u32));
+ }
+
+ if (gwj->dropped_frames) {
+ if (nla_put_u32(skb, CGW_DROPPED, gwj->dropped_frames) < 0)
+ goto cancel;
+ else
+ nlh->nlmsg_len += NLA_HDRLEN + NLA_ALIGN(sizeof(u32));
+ }
+
+ /* check non default settings of attributes */
+
+ if (gwj->mod.modtype.and) {
+ memcpy(&mb.cf, &gwj->mod.modframe.and, sizeof(mb.cf));
+ mb.modtype = gwj->mod.modtype.and;
+ if (nla_put(skb, CGW_MOD_AND, sizeof(mb), &mb) < 0)
+ goto cancel;
+ else
+ nlh->nlmsg_len += NLA_HDRLEN + NLA_ALIGN(sizeof(mb));
+ }
+
+ if (gwj->mod.modtype.or) {
+ memcpy(&mb.cf, &gwj->mod.modframe.or, sizeof(mb.cf));
+ mb.modtype = gwj->mod.modtype.or;
+ if (nla_put(skb, CGW_MOD_OR, sizeof(mb), &mb) < 0)
+ goto cancel;
+ else
+ nlh->nlmsg_len += NLA_HDRLEN + NLA_ALIGN(sizeof(mb));
+ }
+
+ if (gwj->mod.modtype.xor) {
+ memcpy(&mb.cf, &gwj->mod.modframe.xor, sizeof(mb.cf));
+ mb.modtype = gwj->mod.modtype.xor;
+ if (nla_put(skb, CGW_MOD_XOR, sizeof(mb), &mb) < 0)
+ goto cancel;
+ else
+ nlh->nlmsg_len += NLA_HDRLEN + NLA_ALIGN(sizeof(mb));
+ }
+
+ if (gwj->mod.modtype.set) {
+ memcpy(&mb.cf, &gwj->mod.modframe.set, sizeof(mb.cf));
+ mb.modtype = gwj->mod.modtype.set;
+ if (nla_put(skb, CGW_MOD_SET, sizeof(mb), &mb) < 0)
+ goto cancel;
+ else
+ nlh->nlmsg_len += NLA_HDRLEN + NLA_ALIGN(sizeof(mb));
+ }
+
+ if (gwj->mod.csumfunc.crc8) {
+ if (nla_put(skb, CGW_CS_CRC8, CGW_CS_CRC8_LEN,
+ &gwj->mod.csum.crc8) < 0)
+ goto cancel;
+ else
+ nlh->nlmsg_len += NLA_HDRLEN + \
+ NLA_ALIGN(CGW_CS_CRC8_LEN);
+ }
+
+ if (gwj->mod.csumfunc.xor) {
+ if (nla_put(skb, CGW_CS_XOR, CGW_CS_XOR_LEN,
+ &gwj->mod.csum.xor) < 0)
+ goto cancel;
+ else
+ nlh->nlmsg_len += NLA_HDRLEN + \
+ NLA_ALIGN(CGW_CS_XOR_LEN);
+ }
+
+ if (gwj->gwtype == CGW_TYPE_CAN_CAN) {
+
+ if (gwj->ccgw.filter.can_id || gwj->ccgw.filter.can_mask) {
+ if (nla_put(skb, CGW_FILTER, sizeof(struct can_filter),
+ &gwj->ccgw.filter) < 0)
+ goto cancel;
+ else
+ nlh->nlmsg_len += NLA_HDRLEN +
+ NLA_ALIGN(sizeof(struct can_filter));
+ }
+
+ if (nla_put_u32(skb, CGW_SRC_IF, gwj->ccgw.src_idx) < 0)
+ goto cancel;
+ else
+ nlh->nlmsg_len += NLA_HDRLEN + NLA_ALIGN(sizeof(u32));
+
+ if (nla_put_u32(skb, CGW_DST_IF, gwj->ccgw.dst_idx) < 0)
+ goto cancel;
+ else
+ nlh->nlmsg_len += NLA_HDRLEN + NLA_ALIGN(sizeof(u32));
+ }
+
+ return skb->len;
+
+cancel:
+ nlmsg_cancel(skb, nlh);
+ return -EMSGSIZE;
+}
+
+/* Dump information about all CAN gateway jobs, in response to RTM_GETROUTE */
+static int cgw_dump_jobs(struct sk_buff *skb, struct netlink_callback *cb)
+{
+ struct cgw_job *gwj = NULL;
+ struct hlist_node *n;
+ int idx = 0;
+ int s_idx = cb->args[0];
+
+ rcu_read_lock();
+ hlist_for_each_entry_rcu(gwj, n, &cgw_list, list) {
+ if (idx < s_idx)
+ goto cont;
+
+ if (cgw_put_job(skb, gwj) < 0)
+ break;
+cont:
+ idx++;
+ }
+ rcu_read_unlock();
+
+ cb->args[0] = idx;
+
+ return skb->len;
+}
+
+/* check for common and gwtype specific attributes */
+static int cgw_parse_attr(struct nlmsghdr *nlh, struct cf_mod *mod,
+ u8 gwtype, void *gwtypeattr)
+{
+ struct nlattr *tb[CGW_MAX+1];
+ struct cgw_frame_mod mb;
+ int modidx = 0;
+ int err = 0;
+
+ /* initialize modification & checksum data space */
+ memset(mod, 0, sizeof(*mod));
+
+ err = nlmsg_parse(nlh, sizeof(struct rtcanmsg), tb, CGW_MAX, NULL);
+ if (err < 0)
+ return err;
+
+ /* check for AND/OR/XOR/SET modifications */
+
+ if (tb[CGW_MOD_AND] &&
+ nla_len(tb[CGW_MOD_AND]) == CGW_MODATTR_LEN) {
+ nla_memcpy(&mb, tb[CGW_MOD_AND], CGW_MODATTR_LEN);
+
+ canframecpy(&mod->modframe.and, &mb.cf);
+ mod->modtype.and = mb.modtype;
+
+ if (mb.modtype & CGW_MOD_ID)
+ mod->modfunc[modidx++] = mod_and_id;
+
+ if (mb.modtype & CGW_MOD_DLC)
+ mod->modfunc[modidx++] = mod_and_dlc;
+
+ if (mb.modtype & CGW_MOD_DATA)
+ mod->modfunc[modidx++] = mod_and_data;
+ }
+
+ if (tb[CGW_MOD_OR] &&
+ nla_len(tb[CGW_MOD_OR]) == CGW_MODATTR_LEN) {
+ nla_memcpy(&mb, tb[CGW_MOD_OR], CGW_MODATTR_LEN);
+
+ canframecpy(&mod->modframe.or, &mb.cf);
+ mod->modtype.or = mb.modtype;
+
+ if (mb.modtype & CGW_MOD_ID)
+ mod->modfunc[modidx++] = mod_or_id;
+
+ if (mb.modtype & CGW_MOD_DLC)
+ mod->modfunc[modidx++] = mod_or_dlc;
+
+ if (mb.modtype & CGW_MOD_DATA)
+ mod->modfunc[modidx++] = mod_or_data;
+ }
+
+ if (tb[CGW_MOD_XOR] &&
+ nla_len(tb[CGW_MOD_XOR]) == CGW_MODATTR_LEN) {
+ nla_memcpy(&mb, tb[CGW_MOD_XOR], CGW_MODATTR_LEN);
+
+ canframecpy(&mod->modframe.xor, &mb.cf);
+ mod->modtype.xor = mb.modtype;
+
+ if (mb.modtype & CGW_MOD_ID)
+ mod->modfunc[modidx++] = mod_xor_id;
+
+ if (mb.modtype & CGW_MOD_DLC)
+ mod->modfunc[modidx++] = mod_xor_dlc;
+
+ if (mb.modtype & CGW_MOD_DATA)
+ mod->modfunc[modidx++] = mod_xor_data;
+ }
+
+ if (tb[CGW_MOD_SET] &&
+ nla_len(tb[CGW_MOD_SET]) == CGW_MODATTR_LEN) {
+ nla_memcpy(&mb, tb[CGW_MOD_SET], CGW_MODATTR_LEN);
+
+ canframecpy(&mod->modframe.set, &mb.cf);
+ mod->modtype.set = mb.modtype;
+
+ if (mb.modtype & CGW_MOD_ID)
+ mod->modfunc[modidx++] = mod_set_id;
+
+ if (mb.modtype & CGW_MOD_DLC)
+ mod->modfunc[modidx++] = mod_set_dlc;
+
+ if (mb.modtype & CGW_MOD_DATA)
+ mod->modfunc[modidx++] = mod_set_data;
+ }
+
+ /* check for checksum operations after CAN frame modifications */
+ if (modidx) {
+
+ if (tb[CGW_CS_CRC8] &&
+ nla_len(tb[CGW_CS_CRC8]) == CGW_CS_CRC8_LEN) {
+
+ struct cgw_csum_crc8 *c = (struct cgw_csum_crc8 *)\
+ nla_data(tb[CGW_CS_CRC8]);
+
+ err = cgw_chk_csum_parms(c->from_idx, c->to_idx,
+ c->result_idx);
+ if (err)
+ return err;
+
+ nla_memcpy(&mod->csum.crc8, tb[CGW_CS_CRC8],
+ CGW_CS_CRC8_LEN);
+
+ /*
+ * select dedicated processing function to reduce
+ * runtime operations in receive hot path.
+ */
+ if (c->from_idx < 0 || c->to_idx < 0 ||
+ c->result_idx < 0)
+ mod->csumfunc.crc8 = cgw_csum_crc8_rel;
+ else if (c->from_idx <= c->to_idx)
+ mod->csumfunc.crc8 = cgw_csum_crc8_pos;
+ else
+ mod->csumfunc.crc8 = cgw_csum_crc8_neg;
+ }
+
+ if (tb[CGW_CS_XOR] &&
+ nla_len(tb[CGW_CS_XOR]) == CGW_CS_XOR_LEN) {
+
+ struct cgw_csum_xor *c = (struct cgw_csum_xor *)\
+ nla_data(tb[CGW_CS_XOR]);
+
+ err = cgw_chk_csum_parms(c->from_idx, c->to_idx,
+ c->result_idx);
+ if (err)
+ return err;
+
+ nla_memcpy(&mod->csum.xor, tb[CGW_CS_XOR],
+ CGW_CS_XOR_LEN);
+
+ /*
+ * select dedicated processing function to reduce
+ * runtime operations in receive hot path.
+ */
+ if (c->from_idx < 0 || c->to_idx < 0 ||
+ c->result_idx < 0)
+ mod->csumfunc.xor = cgw_csum_xor_rel;
+ else if (c->from_idx <= c->to_idx)
+ mod->csumfunc.xor = cgw_csum_xor_pos;
+ else
+ mod->csumfunc.xor = cgw_csum_xor_neg;
+ }
+ }
+
+ if (gwtype == CGW_TYPE_CAN_CAN) {
+
+ /* check CGW_TYPE_CAN_CAN specific attributes */
+
+ struct can_can_gw *ccgw = (struct can_can_gw *)gwtypeattr;
+ memset(ccgw, 0, sizeof(*ccgw));
+
+ /* check for can_filter in attributes */
+ if (tb[CGW_FILTER] &&
+ nla_len(tb[CGW_FILTER]) == sizeof(struct can_filter))
+ nla_memcpy(&ccgw->filter, tb[CGW_FILTER],
+ sizeof(struct can_filter));
+
+ err = -ENODEV;
+
+ /* specifying two interfaces is mandatory */
+ if (!tb[CGW_SRC_IF] || !tb[CGW_DST_IF])
+ return err;
+
+ if (nla_len(tb[CGW_SRC_IF]) == sizeof(u32))
+ nla_memcpy(&ccgw->src_idx, tb[CGW_SRC_IF],
+ sizeof(u32));
+
+ if (nla_len(tb[CGW_DST_IF]) == sizeof(u32))
+ nla_memcpy(&ccgw->dst_idx, tb[CGW_DST_IF],
+ sizeof(u32));
+
+ /* both indices set to 0 for flushing all routing entries */
+ if (!ccgw->src_idx && !ccgw->dst_idx)
+ return 0;
+
+ /* only one index set to 0 is an error */
+ if (!ccgw->src_idx || !ccgw->dst_idx)
+ return err;
+ }
+
+ /* add the checks for other gwtypes here */
+
+ return 0;
+}
+
+static int cgw_create_job(struct sk_buff *skb, struct nlmsghdr *nlh,
+ void *arg)
+{
+ struct rtcanmsg *r;
+ struct cgw_job *gwj;
+ int err = 0;
+
+ if (nlmsg_len(nlh) < sizeof(*r))
+ return -EINVAL;
+
+ r = nlmsg_data(nlh);
+ if (r->can_family != AF_CAN)
+ return -EPFNOSUPPORT;
+
+ /* so far we only support CAN -> CAN routings */
+ if (r->gwtype != CGW_TYPE_CAN_CAN)
+ return -EINVAL;
+
+ gwj = kmem_cache_alloc(cgw_cache, GFP_KERNEL);
+ if (!gwj)
+ return -ENOMEM;
+
+ gwj->handled_frames = 0;
+ gwj->dropped_frames = 0;
+ gwj->flags = r->flags;
+ gwj->gwtype = r->gwtype;
+
+ err = cgw_parse_attr(nlh, &gwj->mod, CGW_TYPE_CAN_CAN, &gwj->ccgw);
+ if (err < 0)
+ goto out;
+
+ err = -ENODEV;
+
+ /* ifindex == 0 is not allowed for job creation */
+ if (!gwj->ccgw.src_idx || !gwj->ccgw.dst_idx)
+ goto out;
+
+ gwj->src.dev = dev_get_by_index(&init_net, gwj->ccgw.src_idx);
+
+ if (!gwj->src.dev)
+ goto out;
+
+ /* check for CAN netdev not using header_ops - see gw_rcv() */
+ if (gwj->src.dev->type != ARPHRD_CAN || gwj->src.dev->header_ops)
+ goto put_src_out;
+
+ gwj->dst.dev = dev_get_by_index(&init_net, gwj->ccgw.dst_idx);
+
+ if (!gwj->dst.dev)
+ goto put_src_out;
+
+ /* check for CAN netdev not using header_ops - see gw_rcv() */
+ if (gwj->dst.dev->type != ARPHRD_CAN || gwj->dst.dev->header_ops)
+ goto put_src_dst_out;
+
+ ASSERT_RTNL();
+
+ err = cgw_register_filter(gwj);
+ if (!err)
+ hlist_add_head_rcu(&gwj->list, &cgw_list);
+
+put_src_dst_out:
+ dev_put(gwj->dst.dev);
+put_src_out:
+ dev_put(gwj->src.dev);
+out:
+ if (err)
+ kmem_cache_free(cgw_cache, gwj);
+
+ return err;
+}
+
+static void cgw_remove_all_jobs(void)
+{
+ struct cgw_job *gwj = NULL;
+ struct hlist_node *n, *nx;
+
+ ASSERT_RTNL();
+
+ hlist_for_each_entry_safe(gwj, n, nx, &cgw_list, list) {
+ hlist_del(&gwj->list);
+ cgw_unregister_filter(gwj);
+ kfree(gwj);
+ }
+}
+
+static int cgw_remove_job(struct sk_buff *skb, struct nlmsghdr *nlh, void *arg)
+{
+ struct cgw_job *gwj = NULL;
+ struct hlist_node *n, *nx;
+ struct rtcanmsg *r;
+ struct cf_mod mod;
+ struct can_can_gw ccgw;
+ int err = 0;
+
+ if (nlmsg_len(nlh) < sizeof(*r))
+ return -EINVAL;
+
+ r = nlmsg_data(nlh);
+ if (r->can_family != AF_CAN)
+ return -EPFNOSUPPORT;
+
+ /* so far we only support CAN -> CAN routings */
+ if (r->gwtype != CGW_TYPE_CAN_CAN)
+ return -EINVAL;
+
+ err = cgw_parse_attr(nlh, &mod, CGW_TYPE_CAN_CAN, &ccgw);
+ if (err < 0)
+ return err;
+
+ /* two interface indices both set to 0 => remove all entries */
+ if (!ccgw.src_idx && !ccgw.dst_idx) {
+ cgw_remove_all_jobs();
+ return 0;
+ }
+
+ err = -EINVAL;
+
+ ASSERT_RTNL();
+
+ /* remove only the first matching entry */
+ hlist_for_each_entry_safe(gwj, n, nx, &cgw_list, list) {
+
+ if (gwj->flags != r->flags)
+ continue;
+
+ if (memcmp(&gwj->mod, &mod, sizeof(mod)))
+ continue;
+
+ /* if (r->gwtype == CGW_TYPE_CAN_CAN) - is made sure here */
+ if (memcmp(&gwj->ccgw, &ccgw, sizeof(ccgw)))
+ continue;
+
+ hlist_del(&gwj->list);
+ cgw_unregister_filter(gwj);
+ kfree(gwj);
+ err = 0;
+ break;
+ }
+
+ return err;
+}
+
+static __init int cgw_module_init(void)
+{
+ printk(banner);
+
+ cgw_cache = kmem_cache_create("can_gw", sizeof(struct cgw_job),
+ 0, 0, NULL);
+
+ if (!cgw_cache)
+ return -ENOMEM;
+
+ /* set notifier */
+ notifier.notifier_call = cgw_notifier;
+ register_netdevice_notifier(¬ifier);
+
+ if (__rtnl_register(PF_CAN, RTM_GETROUTE, NULL, cgw_dump_jobs, NULL)) {
+ unregister_netdevice_notifier(¬ifier);
+ kmem_cache_destroy(cgw_cache);
+ return -ENOBUFS;
+ }
+
+ /* Only the first call to __rtnl_register can fail */
+ __rtnl_register(PF_CAN, RTM_NEWROUTE, cgw_create_job, NULL, NULL);
+ __rtnl_register(PF_CAN, RTM_DELROUTE, cgw_remove_job, NULL, NULL);
+
+ return 0;
+}
+
+static __exit void cgw_module_exit(void)
+{
+ rtnl_unregister_all(PF_CAN);
+
+ unregister_netdevice_notifier(¬ifier);
+
+ rtnl_lock();
+ cgw_remove_all_jobs();
+ rtnl_unlock();
+
+ rcu_barrier(); /* Wait for completion of call_rcu()'s */
+
+ kmem_cache_destroy(cgw_cache);
+}
+
+module_init(cgw_module_init);
+module_exit(cgw_module_exit);
diff -u -r -N a/net/can/Kconfig b/net/can/Kconfig
--- a/net/can/Kconfig 2011-08-31 21:10:58.399595821 +0200
+++ b/net/can/Kconfig 2011-08-31 21:09:29.939596430 +0200
@@ -40,5 +40,16 @@
CAN messages are used on the bus (e.g. in automotive environments).
To use the Broadcast Manager, use AF_CAN with protocol CAN_BCM.
+config CAN_GW
+ tristate "CAN Gateway/Router (with netlink configuration)"
+ depends on CAN
+ default N
+ ---help---
+ The CAN Gateway/Router is used to route (and modify) CAN frames.
+ It is based on the PF_CAN core infrastructure for msg filtering and
+ msg sending and can optionally modify routed CAN frames on the fly.
+ CAN frames can be routed between CAN network interfaces (one hop).
+ They can be modified with AND/OR/XOR/SET operations as configured
+ by the netlink configuration interface known e.g. from iptables.
source "drivers/net/can/Kconfig"
diff -u -r -N a/net/can/Makefile b/net/can/Makefile
--- a/net/can/Makefile 2011-08-31 21:10:53.355595713 +0200
+++ b/net/can/Makefile 2011-08-31 21:09:34.483599007 +0200
@@ -10,3 +10,6 @@
obj-$(CONFIG_CAN_BCM) += can-bcm.o
can-bcm-y := bcm.o
+
+obj-$(CONFIG_CAN_GW) += can-gw.o
+can-gw-y := gw.o
--
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