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![Andrew Lunn](/assets/img/avatar_default.png)
Simple fixes which require no deep knowledge of the code. Cc: Jamal Hadi Salim <jhs@mojatatu.com> Cc: Cong Wang <xiyou.wangcong@gmail.com> Cc: Jiri Pirko <jiri@resnulli.us> Signed-off-by: Andrew Lunn <andrew@lunn.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
230 lines
5.3 KiB
C
230 lines
5.3 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* em_canid.c Ematch rule to match CAN frames according to their CAN IDs
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*
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* Idea: Oliver Hartkopp <oliver.hartkopp@volkswagen.de>
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* Copyright: (c) 2011 Czech Technical University in Prague
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* (c) 2011 Volkswagen Group Research
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* Authors: Michal Sojka <sojkam1@fel.cvut.cz>
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* Pavel Pisa <pisa@cmp.felk.cvut.cz>
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* Rostislav Lisovy <lisovy@gmail.cz>
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* Funded by: Volkswagen Group Research
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*/
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#include <linux/slab.h>
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#include <linux/module.h>
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#include <linux/types.h>
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#include <linux/kernel.h>
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#include <linux/string.h>
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#include <linux/skbuff.h>
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#include <net/pkt_cls.h>
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#include <linux/can.h>
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#define EM_CAN_RULES_MAX 500
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struct canid_match {
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/* For each SFF CAN ID (11 bit) there is one record in this bitfield */
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DECLARE_BITMAP(match_sff, (1 << CAN_SFF_ID_BITS));
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int rules_count;
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int sff_rules_count;
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int eff_rules_count;
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/*
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* Raw rules copied from netlink message; Used for sending
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* information to userspace (when 'tc filter show' is invoked)
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* AND when matching EFF frames
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*/
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struct can_filter rules_raw[];
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};
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/**
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* em_canid_get_id() - Extracts Can ID out of the sk_buff structure.
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* @skb: buffer to extract Can ID from
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*/
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static canid_t em_canid_get_id(struct sk_buff *skb)
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{
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/* CAN ID is stored within the data field */
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struct can_frame *cf = (struct can_frame *)skb->data;
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return cf->can_id;
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}
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static void em_canid_sff_match_add(struct canid_match *cm, u32 can_id,
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u32 can_mask)
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{
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int i;
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/*
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* Limit can_mask and can_id to SFF range to
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* protect against write after end of array
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*/
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can_mask &= CAN_SFF_MASK;
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can_id &= can_mask;
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/* Single frame */
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if (can_mask == CAN_SFF_MASK) {
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set_bit(can_id, cm->match_sff);
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return;
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}
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/* All frames */
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if (can_mask == 0) {
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bitmap_fill(cm->match_sff, (1 << CAN_SFF_ID_BITS));
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return;
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}
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/*
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* Individual frame filter.
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* Add record (set bit to 1) for each ID that
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* conforms particular rule
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*/
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for (i = 0; i < (1 << CAN_SFF_ID_BITS); i++) {
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if ((i & can_mask) == can_id)
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set_bit(i, cm->match_sff);
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}
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}
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static inline struct canid_match *em_canid_priv(struct tcf_ematch *m)
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{
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return (struct canid_match *)m->data;
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}
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static int em_canid_match(struct sk_buff *skb, struct tcf_ematch *m,
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struct tcf_pkt_info *info)
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{
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struct canid_match *cm = em_canid_priv(m);
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canid_t can_id;
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int match = 0;
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int i;
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const struct can_filter *lp;
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can_id = em_canid_get_id(skb);
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if (can_id & CAN_EFF_FLAG) {
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for (i = 0, lp = cm->rules_raw;
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i < cm->eff_rules_count; i++, lp++) {
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if (!(((lp->can_id ^ can_id) & lp->can_mask))) {
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match = 1;
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break;
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}
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}
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} else { /* SFF */
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can_id &= CAN_SFF_MASK;
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match = (test_bit(can_id, cm->match_sff) ? 1 : 0);
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}
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return match;
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}
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static int em_canid_change(struct net *net, void *data, int len,
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struct tcf_ematch *m)
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{
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struct can_filter *conf = data; /* Array with rules */
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struct canid_match *cm;
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int i;
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if (!len)
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return -EINVAL;
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if (len % sizeof(struct can_filter))
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return -EINVAL;
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if (len > sizeof(struct can_filter) * EM_CAN_RULES_MAX)
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return -EINVAL;
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cm = kzalloc(sizeof(struct canid_match) + len, GFP_KERNEL);
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if (!cm)
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return -ENOMEM;
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cm->rules_count = len / sizeof(struct can_filter);
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/*
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* We need two for() loops for copying rules into two contiguous
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* areas in rules_raw to process all eff rules with a simple loop.
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* NB: The configuration interface supports sff and eff rules.
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* We do not support filters here that match for the same can_id
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* provided in a SFF and EFF frame (e.g. 0x123 / 0x80000123).
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* For this (unusual case) two filters have to be specified. The
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* SFF/EFF separation is done with the CAN_EFF_FLAG in the can_id.
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*/
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/* Fill rules_raw with EFF rules first */
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for (i = 0; i < cm->rules_count; i++) {
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if (conf[i].can_id & CAN_EFF_FLAG) {
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memcpy(cm->rules_raw + cm->eff_rules_count,
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&conf[i],
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sizeof(struct can_filter));
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cm->eff_rules_count++;
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}
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}
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/* append SFF frame rules */
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for (i = 0; i < cm->rules_count; i++) {
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if (!(conf[i].can_id & CAN_EFF_FLAG)) {
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memcpy(cm->rules_raw
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+ cm->eff_rules_count
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+ cm->sff_rules_count,
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&conf[i], sizeof(struct can_filter));
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cm->sff_rules_count++;
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em_canid_sff_match_add(cm,
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conf[i].can_id, conf[i].can_mask);
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}
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}
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m->datalen = sizeof(struct canid_match) + len;
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m->data = (unsigned long)cm;
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return 0;
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}
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static void em_canid_destroy(struct tcf_ematch *m)
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{
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struct canid_match *cm = em_canid_priv(m);
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kfree(cm);
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}
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static int em_canid_dump(struct sk_buff *skb, struct tcf_ematch *m)
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{
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struct canid_match *cm = em_canid_priv(m);
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/*
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* When configuring this ematch 'rules_count' is set not to exceed
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* 'rules_raw' array size
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*/
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if (nla_put_nohdr(skb, sizeof(struct can_filter) * cm->rules_count,
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&cm->rules_raw) < 0)
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return -EMSGSIZE;
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return 0;
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}
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static struct tcf_ematch_ops em_canid_ops = {
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.kind = TCF_EM_CANID,
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.change = em_canid_change,
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.match = em_canid_match,
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.destroy = em_canid_destroy,
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.dump = em_canid_dump,
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.owner = THIS_MODULE,
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.link = LIST_HEAD_INIT(em_canid_ops.link)
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};
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static int __init init_em_canid(void)
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{
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return tcf_em_register(&em_canid_ops);
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}
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static void __exit exit_em_canid(void)
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{
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tcf_em_unregister(&em_canid_ops);
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}
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MODULE_LICENSE("GPL");
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module_init(init_em_canid);
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module_exit(exit_em_canid);
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MODULE_ALIAS_TCF_EMATCH(TCF_EM_CANID);
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