Initial import

1 files changed, 233 insertions, 0 deletions

diff --git a/net/sched/em_canid.c b/net/sched/em_canid.c
new file mode 100644
index 000000000..ddd883ca5
--- /dev/null
+++ b/net/sched/em_canid.c
@@ -0,0 +1,233 @@
+/*
+ * em_canid.c  Ematch rule to match CAN frames according to their CAN IDs
+ *
+ *              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 <linux/slab.h>
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/string.h>
+#include <linux/skbuff.h>
+#include <net/pkt_cls.h>
+#include <linux/can.h>
+
+#define EM_CAN_RULES_MAX 500
+
+struct canid_match {
+	/* For each SFF CAN ID (11 bit) there is one record in this bitfield */
+	DECLARE_BITMAP(match_sff, (1 << CAN_SFF_ID_BITS));
+
+	int rules_count;
+	int sff_rules_count;
+	int eff_rules_count;
+
+	/*
+	 * Raw rules copied from netlink message; Used for sending
+	 * information to userspace (when 'tc filter show' is invoked)
+	 * AND when matching EFF frames
+	 */
+	struct can_filter rules_raw[];
+};
+
+/**
+ * em_canid_get_id() - Extracts Can ID out of the sk_buff structure.
+ */
+static canid_t em_canid_get_id(struct sk_buff *skb)
+{
+	/* CAN ID is stored within the data field */
+	struct can_frame *cf = (struct can_frame *)skb->data;
+
+	return cf->can_id;
+}
+
+static void em_canid_sff_match_add(struct canid_match *cm, u32 can_id,
+					u32 can_mask)
+{
+	int i;
+
+	/*
+	 * Limit can_mask and can_id to SFF range to
+	 * protect against write after end of array
+	 */
+	can_mask &= CAN_SFF_MASK;
+	can_id &= can_mask;
+
+	/* Single frame */
+	if (can_mask == CAN_SFF_MASK) {
+		set_bit(can_id, cm->match_sff);
+		return;
+	}
+
+	/* All frames */
+	if (can_mask == 0) {
+		bitmap_fill(cm->match_sff, (1 << CAN_SFF_ID_BITS));
+		return;
+	}
+
+	/*
+	 * Individual frame filter.
+	 * Add record (set bit to 1) for each ID that
+	 * conforms particular rule
+	 */
+	for (i = 0; i < (1 << CAN_SFF_ID_BITS); i++) {
+		if ((i & can_mask) == can_id)
+			set_bit(i, cm->match_sff);
+	}
+}
+
+static inline struct canid_match *em_canid_priv(struct tcf_ematch *m)
+{
+	return (struct canid_match *)m->data;
+}
+
+static int em_canid_match(struct sk_buff *skb, struct tcf_ematch *m,
+			 struct tcf_pkt_info *info)
+{
+	struct canid_match *cm = em_canid_priv(m);
+	canid_t can_id;
+	int match = 0;
+	int i;
+	const struct can_filter *lp;
+
+	can_id = em_canid_get_id(skb);
+
+	if (can_id & CAN_EFF_FLAG) {
+		for (i = 0, lp = cm->rules_raw;
+		     i < cm->eff_rules_count; i++, lp++) {
+			if (!(((lp->can_id ^ can_id) & lp->can_mask))) {
+				match = 1;
+				break;
+			}
+		}
+	} else { /* SFF */
+		can_id &= CAN_SFF_MASK;
+		match = (test_bit(can_id, cm->match_sff) ? 1 : 0);
+	}
+
+	return match;
+}
+
+static int em_canid_change(struct net *net, void *data, int len,
+			  struct tcf_ematch *m)
+{
+	struct can_filter *conf = data; /* Array with rules */
+	struct canid_match *cm;
+	int i;
+
+	if (!len)
+		return -EINVAL;
+
+	if (len % sizeof(struct can_filter))
+		return -EINVAL;
+
+	if (len > sizeof(struct can_filter) * EM_CAN_RULES_MAX)
+		return -EINVAL;
+
+	cm = kzalloc(sizeof(struct canid_match) + len, GFP_KERNEL);
+	if (!cm)
+		return -ENOMEM;
+
+	cm->rules_count = len / sizeof(struct can_filter);
+
+	/*
+	 * We need two for() loops for copying rules into two contiguous
+	 * areas in rules_raw to process all eff rules with a simple loop.
+	 * NB: The configuration interface supports sff and eff rules.
+	 * We do not support filters here that match for the same can_id
+	 * provided in a SFF and EFF frame (e.g. 0x123 / 0x80000123).
+	 * For this (unusual case) two filters have to be specified. The
+	 * SFF/EFF separation is done with the CAN_EFF_FLAG in the can_id.
+	 */
+
+	/* Fill rules_raw with EFF rules first */
+	for (i = 0; i < cm->rules_count; i++) {
+		if (conf[i].can_id & CAN_EFF_FLAG) {
+			memcpy(cm->rules_raw + cm->eff_rules_count,
+				&conf[i],
+				sizeof(struct can_filter));
+
+			cm->eff_rules_count++;
+		}
+	}
+
+	/* append SFF frame rules */
+	for (i = 0; i < cm->rules_count; i++) {
+		if (!(conf[i].can_id & CAN_EFF_FLAG)) {
+			memcpy(cm->rules_raw
+				+ cm->eff_rules_count
+				+ cm->sff_rules_count,
+				&conf[i], sizeof(struct can_filter));
+
+			cm->sff_rules_count++;
+
+			em_canid_sff_match_add(cm,
+				conf[i].can_id, conf[i].can_mask);
+		}
+	}
+
+	m->datalen = sizeof(struct canid_match) + len;
+	m->data = (unsigned long)cm;
+	return 0;
+}
+
+static void em_canid_destroy(struct tcf_ematch *m)
+{
+	struct canid_match *cm = em_canid_priv(m);
+
+	kfree(cm);
+}
+
+static int em_canid_dump(struct sk_buff *skb, struct tcf_ematch *m)
+{
+	struct canid_match *cm = em_canid_priv(m);
+
+	/*
+	 * When configuring this ematch 'rules_count' is set not to exceed
+	 * 'rules_raw' array size
+	 */
+	if (nla_put_nohdr(skb, sizeof(struct can_filter) * cm->rules_count,
+	    &cm->rules_raw) < 0)
+		return -EMSGSIZE;
+
+	return 0;
+}
+
+static struct tcf_ematch_ops em_canid_ops = {
+	.kind	  = TCF_EM_CANID,
+	.change	  = em_canid_change,
+	.match	  = em_canid_match,
+	.destroy  = em_canid_destroy,
+	.dump	  = em_canid_dump,
+	.owner	  = THIS_MODULE,
+	.link	  = LIST_HEAD_INIT(em_canid_ops.link)
+};
+
+static int __init init_em_canid(void)
+{
+	return tcf_em_register(&em_canid_ops);
+}
+
+static void __exit exit_em_canid(void)
+{
+	tcf_em_unregister(&em_canid_ops);
+}
+
+MODULE_LICENSE("GPL");
+
+module_init(init_em_canid);
+module_exit(exit_em_canid);
+
+MODULE_ALIAS_TCF_EMATCH(TCF_EM_CANID);