[PATCH iproute2 0/3] CAN Filter/Classifier

[PATCH iproute2 0/3] CAN Filter/Classifier

[Rostislav Lisovy]

The CAN classifier may be used with any available qdisc on Controller
Area Network (CAN) frames passed through AF_CAN networking subsystem.
The classifier classifies CAN frames according to their identifiers.
It can be used on CAN frames with both SFF or EFF identifiers.

The filtering rules for EFF frames are stored in an array, which
is traversed during classification. A bitmap is used to store SFF
rules -- one bit for each ID.

More info about the project:
http://rtime.felk.cvut.cz/can/socketcan-qdisc-final.pdf


Rostislav Lisovy (3):
  Added missing can.h
  CAN Filter/Classifier -- Source code
  CAN Filter/Classifier -- Documentation

 include/linux/can.h     |  112 ++++++++++++++++++++++
 include/linux/pkt_cls.h |   10 ++
 man/man8/tc-can.8       |   97 +++++++++++++++++++
 tc/Makefile             |    1 +
 tc/f_can.c              |  238 +++++++++++++++++++++++++++++++++++++++++++++++
 5 files changed, 458 insertions(+)
 create mode 100644 include/linux/can.h
 create mode 100644 man/man8/tc-can.8
 create mode 100644 tc/f_can.c

-- 
1.7.9.5

[PATCH iproute2 1/3] Added missing can.h

[Rostislav Lisovy]

This header file is slightly modified version copied from
Linux kernel v. 3.3. It contains defines necessary for AF_CAN
communication.

Signed-off-by: Rostislav Lisovy <lisovy@gmail.com>
---
 include/linux/can.h |  112 +++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 112 insertions(+)
 create mode 100644 include/linux/can.h

diff --git a/include/linux/can.h b/include/linux/can.h
new file mode 100644
index 0000000..08d1610
--- /dev/null
+++ b/include/linux/can.h
@@ -0,0 +1,112 @@
+/*
+ * linux/can.h
+ *
+ * Definitions for CAN network layer (socket addr / CAN frame / CAN filter)
+ *
+ * Authors: Oliver Hartkopp <oliver.hartkopp@volkswagen.de>
+ *          Urs Thuermann   <urs.thuermann@volkswagen.de>
+ * Copyright (c) 2002-2007 Volkswagen Group Electronic Research
+ * All rights reserved.
+ *
+ */
+
+#ifndef CAN_H
+#define CAN_H
+
+#include <linux/types.h>
+#include <linux/socket.h>
+
+/* controller area network (CAN) kernel definitions */
+
+/* special address description flags for the CAN_ID */
+#define CAN_EFF_FLAG 0x80000000U /* EFF/SFF is set in the MSB */
+#define CAN_RTR_FLAG 0x40000000U /* remote transmission request */
+#define CAN_ERR_FLAG 0x20000000U /* error frame */
+
+/* valid bits in CAN ID for frame formats */
+#define CAN_SFF_MASK 0x000007FFU /* standard frame format (SFF) */
+#define CAN_EFF_MASK 0x1FFFFFFFU /* extended frame format (EFF) */
+#define CAN_ERR_MASK 0x1FFFFFFFU /* omit EFF, RTR, ERR flags */
+
+/*
+ * Controller Area Network Identifier structure
+ *
+ * bit 0-28	: CAN identifier (11/29 bit)
+ * bit 29	: error frame flag (0 = data frame, 1 = error frame)
+ * bit 30	: remote transmission request flag (1 = rtr frame)
+ * bit 31	: frame format flag (0 = standard 11 bit, 1 = extended 29 bit)
+ */
+typedef __u32 canid_t;
+
+#define CAN_SFF_ID_BITS		11
+#define CAN_EFF_ID_BITS		29
+
+/*
+ * Controller Area Network Error Frame Mask structure
+ *
+ * bit 0-28	: error class mask (see include/linux/can/error.h)
+ * bit 29-31	: set to zero
+ */
+typedef __u32 can_err_mask_t;
+
+/**
+ * struct can_frame - basic CAN frame structure
+ * @can_id:  the CAN ID of the frame and CAN_*_FLAG flags, see above.
+ * @can_dlc: the data length field of the CAN frame
+ * @data:    the CAN frame payload.
+ */
+struct can_frame {
+	canid_t can_id;  /* 32 bit CAN_ID + EFF/RTR/ERR flags */
+	__u8    can_dlc; /* data length code: 0 .. 8 */
+	__u8    data[8] __attribute__((aligned(8)));
+};
+
+/* particular protocols of the protocol family PF_CAN */
+#define CAN_RAW		1 /* RAW sockets */
+#define CAN_BCM		2 /* Broadcast Manager */
+#define CAN_TP16	3 /* VAG Transport Protocol v1.6 */
+#define CAN_TP20	4 /* VAG Transport Protocol v2.0 */
+#define CAN_MCNET	5 /* Bosch MCNet */
+#define CAN_ISOTP	6 /* ISO 15765-2 Transport Protocol */
+#define CAN_NPROTO	7
+
+#define SOL_CAN_BASE 100
+
+/**
+ * struct sockaddr_can - the sockaddr structure for CAN sockets
+ * @can_family:  address family number AF_CAN.
+ * @can_ifindex: CAN network interface index.
+ * @can_addr:    protocol specific address information
+ */
+struct sockaddr_can {
+	__kernel_sa_family_t can_family;
+	int         can_ifindex;
+	union {
+		/* transport protocol class address information (e.g. ISOTP) */
+		struct { canid_t rx_id, tx_id; } tp;
+
+		/* reserved for future CAN protocols address information */
+	} can_addr;
+};
+
+/**
+ * struct can_filter - CAN ID based filter in can_register().
+ * @can_id:   relevant bits of CAN ID which are not masked out.
+ * @can_mask: CAN mask (see description)
+ *
+ * Description:
+ * A filter matches, when
+ *
+ *          <received_can_id> & mask == can_id & mask
+ *
+ * The filter can be inverted (CAN_INV_FILTER bit set in can_id) or it can
+ * filter for error frames (CAN_ERR_FLAG bit set in mask).
+ */
+struct can_filter {
+	canid_t can_id;
+	canid_t can_mask;
+};
+
+#define CAN_INV_FILTER 0x20000000U /* to be set in can_filter.can_id */
+
+#endif /* CAN_H */
-- 
1.7.9.5

[PATCH iproute2 2/3] CAN Filter/Classifier -- Source code

[Rostislav Lisovy]

The CAN classifier may be used with any available qdisc on Controller
Area Network (CAN) frames passed through AF_CAN networking subsystem.
The classifier classifies CAN frames according to their identifiers.
It can be used on CAN frames with both SFF or EFF identifiers.

The filtering rules for EFF frames are stored in an array, which
is traversed during classification. A bitmap is used to store SFF
rules -- one bit for each ID.

More info about the project:
http://rtime.felk.cvut.cz/can/socketcan-qdisc-final.pdf

Signed-off-by: Rostislav Lisovy <lisovy@gmail.com>
---
 include/linux/pkt_cls.h |   10 ++
 tc/Makefile             |    1 +
 tc/f_can.c              |  238 +++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 249 insertions(+)
 create mode 100644 tc/f_can.c

diff --git a/include/linux/pkt_cls.h b/include/linux/pkt_cls.h
index defbde2..83f9241 100644
--- a/include/linux/pkt_cls.h
+++ b/include/linux/pkt_cls.h
@@ -375,6 +375,16 @@ enum {
 
 #define TCA_BASIC_MAX (__TCA_BASIC_MAX - 1)
 
+/* CAN filter */
+
+enum {
+	TCA_CANFLTR_UNSPEC,
+	TCA_CANFLTR_CLASSID,
+	TCA_CANFLTR_RULES,
+	__TCA_CANFLTR_MAX
+};
+
+#define TCA_CANFLTR_MAX (__TCA_CANFLTR_MAX - 1)
 
 /* Cgroup classifier */
 
diff --git a/tc/Makefile b/tc/Makefile
index 64d93ad..1281568 100644
--- a/tc/Makefile
+++ b/tc/Makefile
@@ -22,6 +22,7 @@ TCMODULES += f_u32.o
 TCMODULES += f_route.o
 TCMODULES += f_fw.o
 TCMODULES += f_basic.o
+TCMODULES += f_can.o
 TCMODULES += f_flow.o
 TCMODULES += f_cgroup.o
 TCMODULES += q_dsmark.o
diff --git a/tc/f_can.c b/tc/f_can.c
new file mode 100644
index 0000000..208625f
--- /dev/null
+++ b/tc/f_can.c
@@ -0,0 +1,238 @@
+/*
+ * f_can.c  Filter for CAN packets
+ *
+ *		This program is free software; you can distribute it and/or
+ *		modify it under the terms of the GNU General Public License
+ *		as published by the Free Software Foundation; either version
+ *		2 of the License, or (at your option) any later version.
+ *
+ * Idea:       Oliver Hartkopp <oliver.hartkopp@volkswagen.de>
+ * Copyright:  (c) 2011 Czech Technical University in Prague
+ *             (c) 2011 Volkswagen Group Research
+ * Authors:    Michal Sojka <sojkam1@fel.cvut.cz>
+ *             Pavel Pisa <pisa@cmp.felk.cvut.cz>
+ *             Rostislav Lisovy <lisovy@gmail.cz>
+ * Funded by:  Volkswagen Group Research
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <syslog.h>
+#include <fcntl.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+#include <string.h>
+#include <linux/if.h>
+#include <limits.h>
+#include <inttypes.h>
+#include "utils.h"
+#include "tc_util.h"
+#include "linux/can.h"
+
+#define RULES_SIZE		128 /* Maximum number of rules sent via the
+				netlink message during creation/configuration */
+
+
+static void canfltr_explain(void)
+{
+	fprintf(stderr, "Usage: ... can [ MATCHSPEC ] [ flowid FLOWID ]\n"
+			"\n"
+			"Where: MATCHSPEC := { sffid FILTERID | effid FILTERID |\n"
+			"                   MATCHSPEC ... }\n"
+			"       FILTERID := CANID[:MASK]\n"
+			"\n"
+			"NOTE: CLASSID, CANID, MASK is parsed as hexadecimal input.\n");
+}
+
+static int canfltr_parse_opt(struct filter_util *qu, char *handle,
+			 int argc, char **argv, struct nlmsghdr *n)
+{
+	struct tcmsg *t = NLMSG_DATA(n);
+	struct rtattr *tail;
+	struct can_filter canfltr_rules[RULES_SIZE];
+	int rules_count = 0;
+	long h = 0;
+	canid_t can_id;
+	canid_t can_mask;
+
+	if (!argc)
+		return 0;
+
+	if (handle) {
+		h = strtol(handle, NULL, 0);
+		if (h == LONG_MIN || h == LONG_MAX) {
+			fprintf(stderr, "Illegal handle \"%s\", must be numeric.\n",
+				handle);
+			return -1;
+		}
+	}
+
+	t->tcm_handle = h;
+
+	tail = NLMSG_TAIL(n);
+	addattr_l(n, MAX_MSG, TCA_OPTIONS, NULL, 0);
+
+	while (argc > 0) {
+		if (matches(*argv, "sffid") == 0) {
+			/* parse SFF CAN ID optionally with mask */
+			if (rules_count >= RULES_SIZE) {
+				fprintf(stderr, "Too much rules on input. "
+					"Maximum number of rules is: %d\n",
+					RULES_SIZE);
+				return -1;
+			}
+
+			NEXT_ARG();
+
+			if (sscanf(*argv, "%"SCNx32 ":" "%"SCNx32,
+				&can_id, &can_mask) != 2) {
+				if (sscanf(*argv, "%"SCNx32, &can_id) != 1) {
+					fprintf(stderr, "Improperly formed CAN "
+						"ID & mask '%s'\n", *argv);
+					return -1;
+				} else
+					can_mask = CAN_SFF_MASK;
+			}
+
+			/* we do not support extra handling for RTR frames
+			due to the bitmap approach */
+			if (can_id & ~CAN_SFF_MASK) {
+				fprintf(stderr, "ID 0x%lx exceeded standard CAN ID range.\n",
+					(unsigned long)can_id);
+				return -1;
+			}
+
+			canfltr_rules[rules_count].can_id = can_id;
+			canfltr_rules[rules_count].can_mask =
+				(can_mask & CAN_SFF_MASK);
+			rules_count++;
+
+		} else if (matches(*argv, "effid") == 0) {
+			/* parse EFF CAN ID optionally with mask */
+			if (rules_count >= RULES_SIZE) {
+				fprintf(stderr, "Too much rules on input. "
+					"Maximum number of rules is: %d\n",
+					RULES_SIZE);
+				return -1;
+			}
+
+			NEXT_ARG();
+
+			if (sscanf(*argv, "%"SCNx32 ":" "%"SCNx32, &can_id, &can_mask) != 2) {
+				if (sscanf(*argv, "%"SCNx32, &can_id) != 1) {
+					fprintf(stderr, "Improperly formed CAN ID & mask '%s'\n", *argv);
+					return -1;
+				} else
+					can_mask = CAN_EFF_MASK;
+			}
+
+			if (can_id & ~CAN_EFF_MASK) {
+				fprintf(stderr, "ID 0x%lx exceeded extended CAN ID range.",
+					(unsigned long)can_id);
+				return -1;
+			}
+
+			canfltr_rules[rules_count].can_id =
+				can_id | CAN_EFF_FLAG;
+			canfltr_rules[rules_count].can_mask =
+				(can_mask & CAN_EFF_MASK) | CAN_EFF_FLAG;
+			rules_count++;
+
+		} else if (matches(*argv, "classid") == 0 || strcmp(*argv, "flowid") == 0) {
+			unsigned handle;
+			NEXT_ARG();
+			if (get_tc_classid(&handle, *argv)) {
+				fprintf(stderr, "Illegal \"classid\"\n");
+				return -1;
+			}
+			addattr_l(n, MAX_MSG, TCA_CANFLTR_CLASSID, &handle, 4);
+
+		} else if (strcmp(*argv, "help") == 0) {
+			canfltr_explain();
+			return -1;
+
+		} else {
+			fprintf(stderr, "What is \"%s\"?\n", *argv);
+			canfltr_explain();
+			return -1;
+		}
+		argc--; argv++;
+	}
+
+	addattr_l(n, MAX_MSG, TCA_CANFLTR_RULES, &canfltr_rules,
+		sizeof(struct can_filter) * rules_count);
+
+	tail->rta_len = (void *)NLMSG_TAIL(n) - (void *)tail;
+	return 0;
+}
+
+/* When "tc filter show dev XY" is executed, function canfltr_walk() (in
+ * kernel) is called (which calls canfltr_dump() for each instance of a
+ * filter) which sends information about each instance of a filter to
+ * userspace -- to this function which parses the message and prints it.
+ */
+static int canfltr_print_opt(struct filter_util *qu, FILE *f,
+			struct rtattr *opt, __u32 handle)
+{
+	struct rtattr *tb[TCA_CANFLTR_MAX+1];
+	struct can_filter *canfltr_rules = NULL;
+	int rules_count = 0;
+	int i;
+
+	if (opt == NULL)
+		return 0;
+
+	parse_rtattr_nested(tb, TCA_CANFLTR_MAX, opt);
+
+	if (handle)
+		fprintf(f, "handle 0x%x ", handle);
+
+
+	if (tb[TCA_BASIC_CLASSID]) {
+		SPRINT_BUF(b1); /* allocates buffer b1 */
+		fprintf(f, "flowid %s ",
+			sprint_tc_classid(*(__u32 *)RTA_DATA(tb[TCA_BASIC_CLASSID]), b1));
+	}
+
+	if (tb[TCA_CANFLTR_RULES]) {
+		if (RTA_PAYLOAD(tb[TCA_CANFLTR_RULES]) < sizeof(struct can_filter))
+			return -1;
+
+		canfltr_rules = RTA_DATA(tb[TCA_CANFLTR_RULES]);
+		rules_count = (RTA_PAYLOAD(tb[TCA_CANFLTR_RULES]) /
+			sizeof(struct can_filter));
+
+		for (i = 0; i < rules_count; i++) {
+			struct can_filter *pcfltr = &canfltr_rules[i];
+
+			if (pcfltr->can_id & CAN_EFF_FLAG) {
+				if (pcfltr->can_mask == (CAN_EFF_FLAG|CAN_EFF_MASK))
+					fprintf(f, "effid 0x%"PRIX32" ",
+						pcfltr->can_id & CAN_EFF_MASK);
+				else
+					fprintf(f, "effid 0x%"PRIX32":0x%"PRIX32" ",
+						pcfltr->can_id & CAN_EFF_MASK,
+						pcfltr->can_mask & CAN_EFF_MASK);
+			} else {
+				if (pcfltr->can_mask == CAN_SFF_MASK)
+					fprintf(f, "sffid 0x%"PRIX32" ",
+						pcfltr->can_id);
+				else
+					fprintf(f, "sffid 0x%"PRIX32":0x%"PRIX32" ",
+						pcfltr->can_id,
+						pcfltr->can_mask);
+			}
+		}
+	}
+
+	return 0;
+}
+
+struct filter_util can_filter_util = {
+	.id = "can",
+	.parse_fopt = canfltr_parse_opt,
+	.print_fopt = canfltr_print_opt,
+};
+
-- 
1.7.9.5

[PATCH iproute2 3/3] CAN Filter/Classifier -- Documentation

[Rostislav Lisovy]

Added manpage describing usage of CAN Filter.

Signed-off-by: Rostislav Lisovy <lisovy@gmail.com>
---
 man/man8/tc-can.8 |   97 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 97 insertions(+)
 create mode 100644 man/man8/tc-can.8

diff --git a/man/man8/tc-can.8 b/man/man8/tc-can.8
new file mode 100644
index 0000000..54ee96a
--- /dev/null
+++ b/man/man8/tc-can.8
@@ -0,0 +1,97 @@
+.TH CAN 8 "8 May 2012" "iproute2" "Linux"
+.SH NAME
+CAN \- Controller Area Network classifier
+.SH SYNOPSIS
+.B tc filter ... dev
+DEV
+.B parent
+CLASSID
+.B [ prio
+PRIORITY
+.B ] [ protocol can ] [ handle 
+HANDLE
+.B ] can [ 
+MATCHSPEC
+.B ] [ flowid 
+FLOWID
+.B ]
+
+.B CLASSID := major:minor
+.br
+.B FLOWID := major:minor
+.br
+.B MATCHSPEC := { sffid 
+FILTERID
+.B | effid 
+FILTERID
+.B | MATCHSPEC ... }
+.br
+.B FILTERID := canid[:mask]
+
+.BR CLASSID ,
+.BR FLOWID ,
+.BR canid
+and
+.B mask
+are parsed as hexadecimal input.
+
+
+.SH DESCRIPTION
+The CAN classifier may be used with any available
+.B qdisc
+on Controller Area Network (CAN) frames passed through AF_CAN
+networking subsystem. The classifier classifies CAN frames according
+to their identifiers. It can be used on CAN frames with both SFF or
+EFF identifiers.
+
+It is possible to add CAN classifier to any qdisc configured on any networking
+device, however it will ignore non-CAN packets.
+
+
+.SH CLASSIFICATION
+The filtering rules for EFF frames are stored in an array, which is traversed
+during classification. This means that the worst-case time needed for
+classification of EFF frames increases with the number of configured rules.
+
+The filter implements an optimization for matching SFF frames using a bitmap
+with one bit for every ID. With this optimization, the classification time
+for SFF frames is nearly constant independently of the number of rules.
+
+.SH EXAMPLE
+This example shows how to set
+.B prio qdisc
+with
+.B CAN
+classifier.
+
+.nf
+tc qdisc add dev can0 root handle 1: prio
+
+tc filter add dev can0 parent 1:0 prio 1 handle 0xa \\
+    can sffid 0x7ff:0xf flowid 1:1
+tc filter add dev can0 parent 1:0 prio 2 handle 0xb \\
+    can sffid 0xC0:0x7ff effid 0x80:0x7ff flowid 1:2
+tc filter add dev can0 parent 1:0 prio 3 \\
+    can sffid 0x80:0x7ff flowid 1:2
+tc filter add dev can0 parent 1:0 prio 4 \\
+    can sffid 0x0:0x0 effid 0x0:0x0 flowid 1:3
+.fi
+
+
+.SH BUGS
+The maximum number or rules passed from
+.BR tc(8)
+utility to CAN classifier is fixed. The limit is set at compilation time
+(default is 128).
+
+
+.SH SEE ALSO
+.BR tc(8)
+
+
+.SH AUTHORS
+Michal Sojka <sojkam1@fel.cvut.cz>, Pavel Pisa <pisa@cmp.felk.cvut.cz>,
+Rostislav Lisovy <lisovy@gmail.cz>.
+
+This manpage maintained by Rostislav Lisovy <lisovy@gmail.com>
+
-- 
1.7.9.5