Hi,
On Wed, 5 May 2021 at 08:59, Oliver Hartkopp <socketcan@xxxxxxxxxxxx> wrote:
> IMO putting linux-can@xxxxxxxxxxxxxxx in CC would be sufficient in this
> stage of discussion.
OK, I've trimmed the receive list.
> On 04.05.21 22:35, Erik Flodin wrote:
> > Add a new flag to can_rx_register/unregister that, when set, requires
> > that the received sk_buff's owning socket matches the socket pointer
> > given when setting the filter. This makes it possible to set a filter
> > that matches all frames sent on a given socket and nothing else.
>
> This is a pretty simple requirement and you are touching almost every
> CAN network layer file.
>
> From this description I would suggest a two-liner to be added in raw.c
>
> diff --git a/net/can/raw.c b/net/can/raw.c
> index 139d9471ddcf..8c6371a0c8a6 100644
> --- a/net/can/raw.c
> +++ b/net/can/raw.c
> @@ -123,10 +123,14 @@ static void raw_rcv(struct sk_buff *oskb, void *data)
>
> /* check the received tx sock reference */
> if (!ro->recv_own_msgs && oskb->sk == sk)
> return;
>
> + /* check the received tx sock reference */
> + if (ro->recv_only_own_msgs && oskb->sk != sk)
> + return;
> +
> /* do not pass non-CAN2.0 frames to a legacy socket */
> if (!ro->fd_frames && oskb->len != CAN_MTU)
> return;
>
> /* eliminate multiple filter matches for the same skb */
>
>
> And then add CAN_RAW_RECV_ONLY_OWN_MSGS accordingly.
>
> Wouldn't that already match your requirements?
I guess that would require me to use two sockets: one for sending
(with RECV_ONLY_OWN_MSGS set) and one for receiving. The problem might
then be how to avoid the second socket seeing the frames sent from the
first, without disabling loopback completly?
// Erik
> >
> > Signed-off-by: Erik Flodin <erik@xxxxxxxxx>
> > ---
> > include/linux/can/core.h | 4 ++--
> > net/can/af_can.c | 50 ++++++++++++++++++++++------------------
> > net/can/af_can.h | 1 +
> > net/can/bcm.c | 9 +++++---
> > net/can/gw.c | 7 +++---
> > net/can/isotp.c | 8 +++----
> > net/can/j1939/main.c | 4 ++--
> > net/can/proc.c | 11 +++++----
> > net/can/raw.c | 10 ++++----
> > 9 files changed, 58 insertions(+), 46 deletions(-)
> >
> > diff --git a/include/linux/can/core.h b/include/linux/can/core.h
> > index 5fb8d0e3f9c1..7ee68128dc10 100644
> > --- a/include/linux/can/core.h
> > +++ b/include/linux/can/core.h
> > @@ -48,12 +48,12 @@ extern int can_proto_register(const struct can_proto *cp);
> > extern void can_proto_unregister(const struct can_proto *cp);
> >
> > int can_rx_register(struct net *net, struct net_device *dev,
> > - canid_t can_id, canid_t mask,
> > + canid_t can_id, canid_t mask, bool match_sk,
> > void (*func)(struct sk_buff *, void *),
> > void *data, char *ident, struct sock *sk);
> >
> > extern void can_rx_unregister(struct net *net, struct net_device *dev,
> > - canid_t can_id, canid_t mask,
> > + canid_t can_id, canid_t mask, bool match_sk,
> > void (*func)(struct sk_buff *, void *),
> > void *data);
> >
> > diff --git a/net/can/af_can.c b/net/can/af_can.c
> > index cce2af10eb3e..7b639c121653 100644
> > --- a/net/can/af_can.c
> > +++ b/net/can/af_can.c
> > @@ -414,6 +414,7 @@ static struct hlist_head *can_rcv_list_find(canid_t *can_id, canid_t *mask,
> > * @dev: pointer to netdevice (NULL => subscribe from 'all' CAN devices list)
> > * @can_id: CAN identifier (see description)
> > * @mask: CAN mask (see description)
> > + * @match_sk: match socket pointer on received sk_buff (see description)
> > * @func: callback function on filter match
> > * @data: returned parameter for callback function
> > * @ident: string for calling module identification
> > @@ -428,6 +429,9 @@ static struct hlist_head *can_rcv_list_find(canid_t *can_id, canid_t *mask,
> > * The filter can be inverted (CAN_INV_FILTER bit set in can_id) or it can
> > * filter for error message frames (CAN_ERR_FLAG bit set in mask).
> > *
> > + * If match_sk is true, the received sk_buff's owning socket must also match
> > + * the given socket pointer.
> > + *
> > * The provided pointer to the sk_buff is guaranteed to be valid as long as
> > * the callback function is running. The callback function must *not* free
> > * the given sk_buff while processing it's task. When the given sk_buff is
> > @@ -440,8 +444,9 @@ static struct hlist_head *can_rcv_list_find(canid_t *can_id, canid_t *mask,
> > * -ENODEV unknown device
> > */
> > int can_rx_register(struct net *net, struct net_device *dev, canid_t can_id,
> > - canid_t mask, void (*func)(struct sk_buff *, void *),
> > - void *data, char *ident, struct sock *sk)
> > + canid_t mask, bool match_sk,
> > + void (*func)(struct sk_buff *, void *), void *data,
> > + char *ident, struct sock *sk)
> > {
> > struct receiver *rcv;
> > struct hlist_head *rcv_list;
> > @@ -468,6 +473,7 @@ int can_rx_register(struct net *net, struct net_device *dev, canid_t can_id,
> >
> > rcv->can_id = can_id;
> > rcv->mask = mask;
> > + rcv->match_sk = match_sk;
> > rcv->matches = 0;
> > rcv->func = func;
> > rcv->data = data;
> > @@ -503,6 +509,7 @@ static void can_rx_delete_receiver(struct rcu_head *rp)
> > * @dev: pointer to netdevice (NULL => unsubscribe from 'all' CAN devices list)
> > * @can_id: CAN identifier
> > * @mask: CAN mask
> > + * @match_sk: match socket pointer on received sk_buff
> > * @func: callback function on filter match
> > * @data: returned parameter for callback function
> > *
> > @@ -510,8 +517,8 @@ static void can_rx_delete_receiver(struct rcu_head *rp)
> > * Removes subscription entry depending on given (subscription) values.
> > */
> > void can_rx_unregister(struct net *net, struct net_device *dev, canid_t can_id,
> > - canid_t mask, void (*func)(struct sk_buff *, void *),
> > - void *data)
> > + canid_t mask, bool match_sk,
> > + void (*func)(struct sk_buff *, void *), void *data)
> > {
> > struct receiver *rcv = NULL;
> > struct hlist_head *rcv_list;
> > @@ -535,7 +542,8 @@ void can_rx_unregister(struct net *net, struct net_device *dev, canid_t can_id,
> > */
> > hlist_for_each_entry_rcu(rcv, rcv_list, list) {
> > if (rcv->can_id == can_id && rcv->mask == mask &&
> > - rcv->func == func && rcv->data == data)
> > + rcv->match_sk == match_sk && rcv->func == func &&
> > + rcv->data == data)
> > break;
> > }
> >
> > @@ -546,8 +554,8 @@ void can_rx_unregister(struct net *net, struct net_device *dev, canid_t can_id,
> > * a warning here.
> > */
> > if (!rcv) {
> > - pr_warn("can: receive list entry not found for dev %s, id %03X, mask %03X\n",
> > - DNAME(dev), can_id, mask);
> > + pr_warn("can: receive list entry not found for dev %s, id %03X, mask %03X%s\n",
> > + DNAME(dev), can_id, mask, match_sk ? " (match sk)" : "");
> > goto out;
> > }
> >
> > @@ -569,10 +577,14 @@ void can_rx_unregister(struct net *net, struct net_device *dev, canid_t can_id,
> > }
> > EXPORT_SYMBOL(can_rx_unregister);
> >
> > -static inline void deliver(struct sk_buff *skb, struct receiver *rcv)
> > +static inline int deliver(struct sk_buff *skb, struct receiver *rcv)
> > {
> > - rcv->func(skb, rcv->data);
> > - rcv->matches++;
> > + if (!rcv->match_sk || skb->sk == rcv->sk) {
> > + rcv->func(skb, rcv->data);
> > + rcv->matches++;
> > + return 1;
> > + }
> > + return 0;
> > }
> >
> > static int can_rcv_filter(struct can_dev_rcv_lists *dev_rcv_lists, struct sk_buff *skb)
> > @@ -589,8 +601,7 @@ static int can_rcv_filter(struct can_dev_rcv_lists *dev_rcv_lists, struct sk_buf
> > /* check for error message frame entries only */
> > hlist_for_each_entry_rcu(rcv, &dev_rcv_lists->rx[RX_ERR], list) {
> > if (can_id & rcv->mask) {
> > - deliver(skb, rcv);
> > - matches++;
> > + matches += deliver(skb, rcv);
> > }
> > }
> > return matches;
> > @@ -598,23 +609,20 @@ static int can_rcv_filter(struct can_dev_rcv_lists *dev_rcv_lists, struct sk_buf
> >
> > /* check for unfiltered entries */
> > hlist_for_each_entry_rcu(rcv, &dev_rcv_lists->rx[RX_ALL], list) {
> > - deliver(skb, rcv);
> > - matches++;
> > + matches += deliver(skb, rcv);
> > }
> >
> > /* check for can_id/mask entries */
> > hlist_for_each_entry_rcu(rcv, &dev_rcv_lists->rx[RX_FIL], list) {
> > if ((can_id & rcv->mask) == rcv->can_id) {
> > - deliver(skb, rcv);
> > - matches++;
> > + matches += deliver(skb, rcv);
> > }
> > }
> >
> > /* check for inverted can_id/mask entries */
> > hlist_for_each_entry_rcu(rcv, &dev_rcv_lists->rx[RX_INV], list) {
> > if ((can_id & rcv->mask) != rcv->can_id) {
> > - deliver(skb, rcv);
> > - matches++;
> > + matches += deliver(skb, rcv);
> > }
> > }
> >
> > @@ -625,15 +633,13 @@ static int can_rcv_filter(struct can_dev_rcv_lists *dev_rcv_lists, struct sk_buf
> > if (can_id & CAN_EFF_FLAG) {
> > hlist_for_each_entry_rcu(rcv, &dev_rcv_lists->rx_eff[effhash(can_id)], list) {
> > if (rcv->can_id == can_id) {
> > - deliver(skb, rcv);
> > - matches++;
> > + matches += deliver(skb, rcv);
> > }
> > }
> > } else {
> > can_id &= CAN_SFF_MASK;
> > hlist_for_each_entry_rcu(rcv, &dev_rcv_lists->rx_sff[can_id], list) {
> > - deliver(skb, rcv);
> > - matches++;
> > + matches += deliver(skb, rcv);
> > }
> > }
> >
> > diff --git a/net/can/af_can.h b/net/can/af_can.h
> > index 7c2d9161e224..ea98b10d93e7 100644
> > --- a/net/can/af_can.h
> > +++ b/net/can/af_can.h
> > @@ -52,6 +52,7 @@ struct receiver {
> > struct hlist_node list;
> > canid_t can_id;
> > canid_t mask;
> > + bool match_sk;
> > unsigned long matches;
> > void (*func)(struct sk_buff *skb, void *data);
> > void *data;
> > diff --git a/net/can/bcm.c b/net/can/bcm.c
> > index 909b9e684e04..d89dd82c2178 100644
> > --- a/net/can/bcm.c
> > +++ b/net/can/bcm.c
> > @@ -729,7 +729,8 @@ static void bcm_rx_unreg(struct net_device *dev, struct bcm_op *op)
> > {
> > if (op->rx_reg_dev == dev) {
> > can_rx_unregister(dev_net(dev), dev, op->can_id,
> > - REGMASK(op->can_id), bcm_rx_handler, op);
> > + REGMASK(op->can_id), false, bcm_rx_handler,
> > + op);
> >
> > /* mark as removed subscription */
> > op->rx_reg_dev = NULL;
> > @@ -775,6 +776,7 @@ static int bcm_delete_rx_op(struct list_head *ops, struct bcm_msg_head *mh,
> > can_rx_unregister(sock_net(op->sk), NULL,
> > op->can_id,
> > REGMASK(op->can_id),
> > + false,
> > bcm_rx_handler, op);
> >
> > list_del(&op->list);
> > @@ -1193,6 +1195,7 @@ static int bcm_rx_setup(struct bcm_msg_head *msg_head, struct msghdr *msg,
> > err = can_rx_register(sock_net(sk), dev,
> > op->can_id,
> > REGMASK(op->can_id),
> > + false,
> > bcm_rx_handler, op,
> > "bcm", sk);
> >
> > @@ -1202,7 +1205,7 @@ static int bcm_rx_setup(struct bcm_msg_head *msg_head, struct msghdr *msg,
> >
> > } else
> > err = can_rx_register(sock_net(sk), NULL, op->can_id,
> > - REGMASK(op->can_id),
> > + REGMASK(op->can_id), false,
> > bcm_rx_handler, op, "bcm", sk);
> > if (err) {
> > /* this bcm rx op is broken -> remove it */
> > @@ -1500,7 +1503,7 @@ static int bcm_release(struct socket *sock)
> > }
> > } else
> > can_rx_unregister(net, NULL, op->can_id,
> > - REGMASK(op->can_id),
> > + REGMASK(op->can_id), false,
> > bcm_rx_handler, op);
> >
> > bcm_remove_op(op);
> > diff --git a/net/can/gw.c b/net/can/gw.c
> > index ba4124805602..5dbc7b85e0fc 100644
> > --- a/net/can/gw.c
> > +++ b/net/can/gw.c
> > @@ -567,14 +567,15 @@ static void can_can_gw_rcv(struct sk_buff *skb, void *data)
> > static inline int cgw_register_filter(struct net *net, struct cgw_job *gwj)
> > {
> > return can_rx_register(net, gwj->src.dev, gwj->ccgw.filter.can_id,
> > - gwj->ccgw.filter.can_mask, can_can_gw_rcv,
> > - gwj, "gw", NULL);
> > + gwj->ccgw.filter.can_mask, false,
> > + can_can_gw_rcv, gwj, "gw", NULL);
> > }
> >
> > static inline void cgw_unregister_filter(struct net *net, struct cgw_job *gwj)
> > {
> > can_rx_unregister(net, gwj->src.dev, gwj->ccgw.filter.can_id,
> > - gwj->ccgw.filter.can_mask, can_can_gw_rcv, gwj);
> > + gwj->ccgw.filter.can_mask, false, can_can_gw_rcv,
> > + gwj);
> > }
> >
> > static int cgw_notifier(struct notifier_block *nb,
> > diff --git a/net/can/isotp.c b/net/can/isotp.c
> > index 9f94ad3caee9..44d943bbe0b1 100644
> > --- a/net/can/isotp.c
> > +++ b/net/can/isotp.c
> > @@ -1029,7 +1029,7 @@ static int isotp_release(struct socket *sock)
> > if (dev) {
> > can_rx_unregister(net, dev, so->rxid,
> > SINGLE_MASK(so->rxid),
> > - isotp_rcv, sk);
> > + false, isotp_rcv, sk);
> > dev_put(dev);
> > }
> > }
> > @@ -1111,7 +1111,7 @@ static int isotp_bind(struct socket *sock, struct sockaddr *uaddr, int len)
> > if (do_rx_reg)
> > can_rx_register(net, dev, addr->can_addr.tp.rx_id,
> > SINGLE_MASK(addr->can_addr.tp.rx_id),
> > - isotp_rcv, sk, "isotp", sk);
> > + false, isotp_rcv, sk, "isotp", sk);
> >
> > dev_put(dev);
> >
> > @@ -1122,7 +1122,7 @@ static int isotp_bind(struct socket *sock, struct sockaddr *uaddr, int len)
> > if (dev) {
> > can_rx_unregister(net, dev, so->rxid,
> > SINGLE_MASK(so->rxid),
> > - isotp_rcv, sk);
> > + false, isotp_rcv, sk);
> > dev_put(dev);
> > }
> > }
> > @@ -1323,7 +1323,7 @@ static int isotp_notifier(struct notifier_block *nb, unsigned long msg,
> > if (so->bound && (!(so->opt.flags & CAN_ISOTP_SF_BROADCAST)))
> > can_rx_unregister(dev_net(dev), dev, so->rxid,
> > SINGLE_MASK(so->rxid),
> > - isotp_rcv, sk);
> > + false, isotp_rcv, sk);
> >
> > so->ifindex = 0;
> > so->bound = 0;
> > diff --git a/net/can/j1939/main.c b/net/can/j1939/main.c
> > index da3a7a7bcff2..466a20c76fb6 100644
> > --- a/net/can/j1939/main.c
> > +++ b/net/can/j1939/main.c
> > @@ -177,7 +177,7 @@ static int j1939_can_rx_register(struct j1939_priv *priv)
> >
> > j1939_priv_get(priv);
> > ret = can_rx_register(dev_net(ndev), ndev, J1939_CAN_ID, J1939_CAN_MASK,
> > - j1939_can_recv, priv, "j1939", NULL);
> > + false, j1939_can_recv, priv, "j1939", NULL);
> > if (ret < 0) {
> > j1939_priv_put(priv);
> > return ret;
> > @@ -191,7 +191,7 @@ static void j1939_can_rx_unregister(struct j1939_priv *priv)
> > struct net_device *ndev = priv->ndev;
> >
> > can_rx_unregister(dev_net(ndev), ndev, J1939_CAN_ID, J1939_CAN_MASK,
> > - j1939_can_recv, priv);
> > + false, j1939_can_recv, priv);
> >
> > j1939_priv_put(priv);
> > }
> > diff --git a/net/can/proc.c b/net/can/proc.c
> > index d1fe49e6f16d..d312077832a6 100644
> > --- a/net/can/proc.c
> > +++ b/net/can/proc.c
> > @@ -191,11 +191,12 @@ static void can_print_rcvlist(struct seq_file *m, struct hlist_head *rx_list,
> >
> > hlist_for_each_entry_rcu(r, rx_list, list) {
> > char *fmt = (r->can_id & CAN_EFF_FLAG)?
> > - " %-5s %08x %08x %pK %pK %8ld %s\n" :
> > - " %-5s %03x %08x %pK %pK %8ld %s\n";
> > + " %-5s %08x %08x %c %pK %pK %8ld %s\n" :
> > + " %-5s %03x %08x %c %pK %pK %8ld %s\n";
> >
> > seq_printf(m, fmt, DNAME(dev), r->can_id, r->mask,
> > - r->func, r->data, r->matches, r->ident);
> > + r->match_sk ? '*' : ' ', r->func, r->data,
> > + r->matches, r->ident);
> > }
> > }
> >
> > @@ -206,9 +207,9 @@ static void can_print_recv_banner(struct seq_file *m)
> > * ....... 0 tp20
> > */
> > if (IS_ENABLED(CONFIG_64BIT))
> > - seq_puts(m, " device can_id can_mask function userdata matches ident\n");
> > + seq_puts(m, " device can_id can_mask own function userdata matches ident\n");
> > else
> > - seq_puts(m, " device can_id can_mask function userdata matches ident\n");
> > + seq_puts(m, " device can_id can_mask own function userdata matches ident\n");
> > }
> >
> > static int can_stats_proc_show(struct seq_file *m, void *v)
> > diff --git a/net/can/raw.c b/net/can/raw.c
> > index 139d9471ddcf..acfbae28d451 100644
> > --- a/net/can/raw.c
> > +++ b/net/can/raw.c
> > @@ -187,13 +187,13 @@ static int raw_enable_filters(struct net *net, struct net_device *dev,
> >
> > for (i = 0; i < count; i++) {
> > err = can_rx_register(net, dev, filter[i].can_id,
> > - filter[i].can_mask,
> > + filter[i].can_mask, false,
> > raw_rcv, sk, "raw", sk);
> > if (err) {
> > /* clean up successfully registered filters */
> > while (--i >= 0)
> > can_rx_unregister(net, dev, filter[i].can_id,
> > - filter[i].can_mask,
> > + filter[i].can_mask, false,
> > raw_rcv, sk);
> > break;
> > }
> > @@ -209,7 +209,7 @@ static int raw_enable_errfilter(struct net *net, struct net_device *dev,
> >
> > if (err_mask)
> > err = can_rx_register(net, dev, 0, err_mask | CAN_ERR_FLAG,
> > - raw_rcv, sk, "raw", sk);
> > + false, raw_rcv, sk, "raw", sk);
> >
> > return err;
> > }
> > @@ -222,7 +222,7 @@ static void raw_disable_filters(struct net *net, struct net_device *dev,
> >
> > for (i = 0; i < count; i++)
> > can_rx_unregister(net, dev, filter[i].can_id,
> > - filter[i].can_mask, raw_rcv, sk);
> > + filter[i].can_mask, false, raw_rcv, sk);
> > }
> >
> > static inline void raw_disable_errfilter(struct net *net,
> > @@ -233,7 +233,7 @@ static inline void raw_disable_errfilter(struct net *net,
> > {
> > if (err_mask)
> > can_rx_unregister(net, dev, 0, err_mask | CAN_ERR_FLAG,
> > - raw_rcv, sk);
> > + false, raw_rcv, sk);
> > }
> >
> > static inline void raw_disable_allfilters(struct net *net,
> >
