can: Fix CAN_(EFF|RTR)_FLAG handling in can_filter
Due to a wrong safety check in af_can.c it was not possible to filter for SFF frames with a specific CAN identifier without getting the same selected CAN identifier from a received EFF frame also. This fix has a minimum (but user visible) impact on the CAN filter API and therefore the CAN version is set to a new date. Indeed the 'old' API is still working as-is. But when now setting CAN_(EFF|RTR)_FLAG in can_filter.can_mask you might get less traffic than before - but still the stuff that you expected to get for your defined filter ... Thanks to Kurt Van Dijck for pointing at this issue and for the review. Signed-off-by: Oliver Hartkopp <oliver@hartkopp.net> Acked-by: Kurt Van Dijck <kurt.van.dijck@eia.be> Signed-off-by: David S. Miller <davem@davemloft.net>
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@ -19,7 +19,7 @@
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#include <linux/skbuff.h>
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#include <linux/skbuff.h>
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#include <linux/netdevice.h>
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#include <linux/netdevice.h>
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#define CAN_VERSION "20071116"
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#define CAN_VERSION "20081130"
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/* increment this number each time you change some user-space interface */
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/* increment this number each time you change some user-space interface */
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#define CAN_ABI_VERSION "8"
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#define CAN_ABI_VERSION "8"
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@ -319,23 +319,52 @@ static struct dev_rcv_lists *find_dev_rcv_lists(struct net_device *dev)
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return n ? d : NULL;
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return n ? d : NULL;
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}
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}
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/**
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* find_rcv_list - determine optimal filterlist inside device filter struct
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* @can_id: pointer to CAN identifier of a given can_filter
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* @mask: pointer to CAN mask of a given can_filter
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* @d: pointer to the device filter struct
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*
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* Description:
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* Returns the optimal filterlist to reduce the filter handling in the
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* receive path. This function is called by service functions that need
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* to register or unregister a can_filter in the filter lists.
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*
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* A filter matches in general, when
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*
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* <received_can_id> & mask == can_id & mask
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*
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* so every bit set in the mask (even CAN_EFF_FLAG, CAN_RTR_FLAG) describe
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* relevant bits for the filter.
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*
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* The filter can be inverted (CAN_INV_FILTER bit set in can_id) or it can
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* filter for error frames (CAN_ERR_FLAG bit set in mask). For error frames
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* there is a special filterlist and a special rx path filter handling.
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*
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* Return:
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* Pointer to optimal filterlist for the given can_id/mask pair.
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* Constistency checked mask.
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* Reduced can_id to have a preprocessed filter compare value.
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*/
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static struct hlist_head *find_rcv_list(canid_t *can_id, canid_t *mask,
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static struct hlist_head *find_rcv_list(canid_t *can_id, canid_t *mask,
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struct dev_rcv_lists *d)
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struct dev_rcv_lists *d)
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{
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{
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canid_t inv = *can_id & CAN_INV_FILTER; /* save flag before masking */
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canid_t inv = *can_id & CAN_INV_FILTER; /* save flag before masking */
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/* filter error frames */
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/* filter for error frames in extra filterlist */
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if (*mask & CAN_ERR_FLAG) {
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if (*mask & CAN_ERR_FLAG) {
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/* clear CAN_ERR_FLAG in list entry */
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/* clear CAN_ERR_FLAG in filter entry */
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*mask &= CAN_ERR_MASK;
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*mask &= CAN_ERR_MASK;
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return &d->rx[RX_ERR];
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return &d->rx[RX_ERR];
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}
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}
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/* ensure valid values in can_mask */
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/* with cleared CAN_ERR_FLAG we have a simple mask/value filterpair */
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if (*mask & CAN_EFF_FLAG)
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*mask &= (CAN_EFF_MASK | CAN_EFF_FLAG | CAN_RTR_FLAG);
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#define CAN_EFF_RTR_FLAGS (CAN_EFF_FLAG | CAN_RTR_FLAG)
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else
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*mask &= (CAN_SFF_MASK | CAN_RTR_FLAG);
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/* ensure valid values in can_mask for 'SFF only' frame filtering */
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if ((*mask & CAN_EFF_FLAG) && !(*can_id & CAN_EFF_FLAG))
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*mask &= (CAN_SFF_MASK | CAN_EFF_RTR_FLAGS);
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/* reduce condition testing at receive time */
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/* reduce condition testing at receive time */
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*can_id &= *mask;
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*can_id &= *mask;
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@ -348,15 +377,19 @@ static struct hlist_head *find_rcv_list(canid_t *can_id, canid_t *mask,
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if (!(*mask))
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if (!(*mask))
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return &d->rx[RX_ALL];
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return &d->rx[RX_ALL];
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/* use extra filterset for the subscription of exactly *ONE* can_id */
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/* extra filterlists for the subscription of a single non-RTR can_id */
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if (*can_id & CAN_EFF_FLAG) {
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if (((*mask & CAN_EFF_RTR_FLAGS) == CAN_EFF_RTR_FLAGS)
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if (*mask == (CAN_EFF_MASK | CAN_EFF_FLAG)) {
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&& !(*can_id & CAN_RTR_FLAG)) {
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/* RFC: a use-case for hash-tables in the future? */
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return &d->rx[RX_EFF];
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if (*can_id & CAN_EFF_FLAG) {
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if (*mask == (CAN_EFF_MASK | CAN_EFF_RTR_FLAGS)) {
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/* RFC: a future use-case for hash-tables? */
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return &d->rx[RX_EFF];
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}
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} else {
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if (*mask == (CAN_SFF_MASK | CAN_EFF_RTR_FLAGS))
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return &d->rx_sff[*can_id];
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}
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}
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} else {
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if (*mask == CAN_SFF_MASK)
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return &d->rx_sff[*can_id];
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}
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}
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/* default: filter via can_id/can_mask */
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/* default: filter via can_id/can_mask */
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@ -64,10 +64,11 @@
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#define BCM_CAN_DLC_MASK 0x0F /* clean private flags in can_dlc by masking */
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#define BCM_CAN_DLC_MASK 0x0F /* clean private flags in can_dlc by masking */
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/* get best masking value for can_rx_register() for a given single can_id */
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/* get best masking value for can_rx_register() for a given single can_id */
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#define REGMASK(id) ((id & CAN_RTR_FLAG) | ((id & CAN_EFF_FLAG) ? \
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#define REGMASK(id) ((id & CAN_EFF_FLAG) ? \
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(CAN_EFF_MASK | CAN_EFF_FLAG) : CAN_SFF_MASK))
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(CAN_EFF_MASK | CAN_EFF_FLAG | CAN_RTR_FLAG) : \
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(CAN_SFF_MASK | CAN_EFF_FLAG | CAN_RTR_FLAG))
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#define CAN_BCM_VERSION "20080415"
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#define CAN_BCM_VERSION CAN_VERSION
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static __initdata const char banner[] = KERN_INFO
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static __initdata const char banner[] = KERN_INFO
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"can: broadcast manager protocol (rev " CAN_BCM_VERSION ")\n";
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"can: broadcast manager protocol (rev " CAN_BCM_VERSION ")\n";
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