net: sched: use block index as a handle instead of qdisc when block is shared

As the tcm_ifindex with value TCM_IFINDEX_MAGIC_BLOCK is invalid ifindex,
use it to indicate that we work with block, instead of qdisc.
So if tcm_ifindex is set to TCM_IFINDEX_MAGIC_BLOCK, tcm_parent is used
to carry block_index.

If the block is set to be shared between at least 2 qdiscs, it is
forbidden to use the qdisc handle to add/delete filters. In that case,
userspace has to pass block_index.

Also, for dump of the filters, in case the block is shared in between at
least 2 qdiscs, the each filter is dumped with tcm_ifindex value
TCM_IFINDEX_MAGIC_BLOCK and tcm_parent set to block_index. That gives
the user clear indication, that the filter belongs to a shared block
and not only to one qdisc under which it is dumped.

Suggested-by: David Ahern <dsahern@gmail.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
Acked-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/uapi/linux/rtnetlink.h b/include/uapi/linux/rtnetlink.h
index 843e29aa3cacf0e06beea9b59af5b5c7acc9ca3b..da878f2e7c3958c5d91587847590cb1e03221553 100644 (file)
--- a/include/uapi/linux/rtnetlink.h
+++ b/include/uapi/linux/rtnetlink.h
@@ -541,9 +541,19 @@ struct tcmsg {
        int             tcm_ifindex;
        __u32           tcm_handle;
        __u32           tcm_parent;
+/* tcm_block_index is used instead of tcm_parent
+ * in case tcm_ifindex == TCM_IFINDEX_MAGIC_BLOCK
+ */
+#define tcm_block_index tcm_parent
        __u32           tcm_info;
 };
 
+/* For manipulation of filters in shared block, tcm_ifindex is set to
+ * TCM_IFINDEX_MAGIC_BLOCK, and tcm_parent is aliased to tcm_block_index
+ * which is the block index.
+ */
+#define TCM_IFINDEX_MAGIC_BLOCK (0xFFFFFFFFU)
+
 enum {
        TCA_UNSPEC,
        TCA_KIND,

diff --git a/net/sched/cls_api.c b/net/sched/cls_api.c
index 03e2fa092d9efb59b1fface2f4604eb0e87b6286..e500d11da9cd5a84d89ab8f6c2b1d0d593651448 100644 (file)
--- a/net/sched/cls_api.c
+++ b/net/sched/cls_api.c
@@ -865,8 +865,9 @@ static struct tcf_proto *tcf_chain_tp_find(struct tcf_chain *chain,
 }
 
 static int tcf_fill_node(struct net *net, struct sk_buff *skb,
-                        struct tcf_proto *tp, struct Qdisc *q, u32 parent,
-                        void *fh, u32 portid, u32 seq, u16 flags, int event)
+                        struct tcf_proto *tp, struct tcf_block *block,
+                        struct Qdisc *q, u32 parent, void *fh,
+                        u32 portid, u32 seq, u16 flags, int event)
 {
        struct tcmsg *tcm;
        struct nlmsghdr  *nlh;
@@ -879,8 +880,13 @@ static int tcf_fill_node(struct net *net, struct sk_buff *skb,
        tcm->tcm_family = AF_UNSPEC;
        tcm->tcm__pad1 = 0;
        tcm->tcm__pad2 = 0;
-       tcm->tcm_ifindex = qdisc_dev(q)->ifindex;
-       tcm->tcm_parent = parent;
+       if (q) {
+               tcm->tcm_ifindex = qdisc_dev(q)->ifindex;
+               tcm->tcm_parent = parent;
+       } else {
+               tcm->tcm_ifindex = TCM_IFINDEX_MAGIC_BLOCK;
+               tcm->tcm_block_index = block->index;
+       }
        tcm->tcm_info = TC_H_MAKE(tp->prio, tp->protocol);
        if (nla_put_string(skb, TCA_KIND, tp->ops->kind))
                goto nla_put_failure;
@@ -903,8 +909,8 @@ nla_put_failure:
 
 static int tfilter_notify(struct net *net, struct sk_buff *oskb,
                          struct nlmsghdr *n, struct tcf_proto *tp,
-                         struct Qdisc *q, u32 parent,
-                         void *fh, int event, bool unicast)
+                         struct tcf_block *block, struct Qdisc *q,
+                         u32 parent, void *fh, int event, bool unicast)
 {
        struct sk_buff *skb;
        u32 portid = oskb ? NETLINK_CB(oskb).portid : 0;
@@ -913,8 +919,8 @@ static int tfilter_notify(struct net *net, struct sk_buff *oskb,
        if (!skb)
                return -ENOBUFS;
 
-       if (tcf_fill_node(net, skb, tp, q, parent, fh, portid, n->nlmsg_seq,
-                         n->nlmsg_flags, event) <= 0) {
+       if (tcf_fill_node(net, skb, tp, block, q, parent, fh, portid,
+                         n->nlmsg_seq, n->nlmsg_flags, event) <= 0) {
                kfree_skb(skb);
                return -EINVAL;
        }
@@ -928,8 +934,8 @@ static int tfilter_notify(struct net *net, struct sk_buff *oskb,
 
 static int tfilter_del_notify(struct net *net, struct sk_buff *oskb,
                              struct nlmsghdr *n, struct tcf_proto *tp,
-                             struct Qdisc *q, u32 parent,
-                             void *fh, bool unicast, bool *last)
+                             struct tcf_block *block, struct Qdisc *q,
+                             u32 parent, void *fh, bool unicast, bool *last)
 {
        struct sk_buff *skb;
        u32 portid = oskb ? NETLINK_CB(oskb).portid : 0;
@@ -939,8 +945,8 @@ static int tfilter_del_notify(struct net *net, struct sk_buff *oskb,
        if (!skb)
                return -ENOBUFS;
 
-       if (tcf_fill_node(net, skb, tp, q, parent, fh, portid, n->nlmsg_seq,
-                         n->nlmsg_flags, RTM_DELTFILTER) <= 0) {
+       if (tcf_fill_node(net, skb, tp, block, q, parent, fh, portid,
+                         n->nlmsg_seq, n->nlmsg_flags, RTM_DELTFILTER) <= 0) {
                kfree_skb(skb);
                return -EINVAL;
        }
@@ -959,15 +965,16 @@ static int tfilter_del_notify(struct net *net, struct sk_buff *oskb,
 }
 
 static void tfilter_notify_chain(struct net *net, struct sk_buff *oskb,
-                                struct Qdisc *q, u32 parent,
-                                struct nlmsghdr *n,
+                                struct tcf_block *block, struct Qdisc *q,
+                                u32 parent, struct nlmsghdr *n,
                                 struct tcf_chain *chain, int event)
 {
        struct tcf_proto *tp;
 
        for (tp = rtnl_dereference(chain->filter_chain);
             tp; tp = rtnl_dereference(tp->next))
-               tfilter_notify(net, oskb, n, tp, q, parent, 0, event, false);
+               tfilter_notify(net, oskb, n, tp, block,
+                              q, parent, 0, event, false);
 }
 
 /* Add/change/delete/get a filter node */
@@ -983,13 +990,11 @@ static int tc_ctl_tfilter(struct sk_buff *skb, struct nlmsghdr *n,
        bool prio_allocate;
        u32 parent;
        u32 chain_index;
-       struct net_device *dev;
-       struct Qdisc  *q;
+       struct Qdisc *q = NULL;
        struct tcf_chain_info chain_info;
        struct tcf_chain *chain = NULL;
        struct tcf_block *block;
        struct tcf_proto *tp;
-       const struct Qdisc_class_ops *cops;
        unsigned long cl;
        void *fh;
        int err;
@@ -1036,41 +1041,58 @@ replay:
 
        /* Find head of filter chain. */
 
-       /* Find link */
-       dev = __dev_get_by_index(net, t->tcm_ifindex);
-       if (dev == NULL)
-               return -ENODEV;
-
-       /* Find qdisc */
-       if (!parent) {
-               q = dev->qdisc;
-               parent = q->handle;
+       if (t->tcm_ifindex == TCM_IFINDEX_MAGIC_BLOCK) {
+               block = tcf_block_lookup(net, t->tcm_block_index);
+               if (!block) {
+                       NL_SET_ERR_MSG(extack, "Block of given index was not found");
+                       err = -EINVAL;
+                       goto errout;
+               }
        } else {
-               q = qdisc_lookup(dev, TC_H_MAJ(t->tcm_parent));
-               if (q == NULL)
-                       return -EINVAL;
-       }
+               const struct Qdisc_class_ops *cops;
+               struct net_device *dev;
 
-       /* Is it classful? */
-       cops = q->ops->cl_ops;
-       if (!cops)
-               return -EINVAL;
+               /* Find link */
+               dev = __dev_get_by_index(net, t->tcm_ifindex);
+               if (!dev)
+                       return -ENODEV;
 
-       if (!cops->tcf_block)
-               return -EOPNOTSUPP;
+               /* Find qdisc */
+               if (!parent) {
+                       q = dev->qdisc;
+                       parent = q->handle;
+               } else {
+                       q = qdisc_lookup(dev, TC_H_MAJ(t->tcm_parent));
+                       if (!q)
+                               return -EINVAL;
+               }
 
-       /* Do we search for filter, attached to class? */
-       if (TC_H_MIN(parent)) {
-               cl = cops->find(q, parent);
-               if (cl == 0)
-                       return -ENOENT;
-       }
+               /* Is it classful? */
+               cops = q->ops->cl_ops;
+               if (!cops)
+                       return -EINVAL;
 
-       /* And the last stroke */
-       block = cops->tcf_block(q, cl, extack);
-       if (!block) {
-               err = -EINVAL;
-               goto errout;
+               if (!cops->tcf_block)
+                       return -EOPNOTSUPP;
+
+               /* Do we search for filter, attached to class? */
+               if (TC_H_MIN(parent)) {
+                       cl = cops->find(q, parent);
+                       if (cl == 0)
+                               return -ENOENT;
+               }
+
+               /* And the last stroke */
+               block = cops->tcf_block(q, cl, extack);
+               if (!block) {
+                       err = -EINVAL;
+                       goto errout;
+               }
+               if (tcf_block_shared(block)) {
+                       NL_SET_ERR_MSG(extack, "This filter block is shared. Please use the block index to manipulate the filters");
+                       err = -EOPNOTSUPP;
+                       goto errout;
+               }
        }
 
        chain_index = tca[TCA_CHAIN] ? nla_get_u32(tca[TCA_CHAIN]) : 0;
@@ -1086,7 +1108,7 @@ replay:
        }
 
        if (n->nlmsg_type == RTM_DELTFILTER && prio == 0) {
-               tfilter_notify_chain(net, skb, q, parent, n,
+               tfilter_notify_chain(net, skb, block, q, parent, n,
                                     chain, RTM_DELTFILTER);
                tcf_chain_flush(chain);
                err = 0;
@@ -1134,7 +1156,7 @@ replay:
        if (!fh) {
                if (n->nlmsg_type == RTM_DELTFILTER && t->tcm_handle == 0) {
                        tcf_chain_tp_remove(chain, &chain_info, tp);
-                       tfilter_notify(net, skb, n, tp, q, parent, fh,
+                       tfilter_notify(net, skb, n, tp, block, q, parent, fh,
                                       RTM_DELTFILTER, false);
                        tcf_proto_destroy(tp);
                        err = 0;
@@ -1159,8 +1181,8 @@ replay:
                        }
                        break;
                case RTM_DELTFILTER:
-                       err = tfilter_del_notify(net, skb, n, tp, q, parent,
-                                                fh, false, &last);
+                       err = tfilter_del_notify(net, skb, n, tp, block,
+                                                q, parent, fh, false, &last);
                        if (err)
                                goto errout;
                        if (last) {
@@ -1169,8 +1191,8 @@ replay:
                        }
                        goto errout;
                case RTM_GETTFILTER:
-                       err = tfilter_notify(net, skb, n, tp, q, parent, fh,
-                                            RTM_NEWTFILTER, true);
+                       err = tfilter_notify(net, skb, n, tp, block, q, parent,
+                                            fh, RTM_NEWTFILTER, true);
                        goto errout;
                default:
                        err = -EINVAL;
@@ -1183,7 +1205,7 @@ replay:
        if (err == 0) {
                if (tp_created)
                        tcf_chain_tp_insert(chain, &chain_info, tp);
-               tfilter_notify(net, skb, n, tp, q, parent, fh,
+               tfilter_notify(net, skb, n, tp, block, q, parent, fh,
                               RTM_NEWTFILTER, false);
        } else {
                if (tp_created)
@@ -1203,6 +1225,7 @@ struct tcf_dump_args {
        struct tcf_walker w;
        struct sk_buff *skb;
        struct netlink_callback *cb;
+       struct tcf_block *block;
        struct Qdisc *q;
        u32 parent;
 };
@@ -1212,7 +1235,7 @@ static int tcf_node_dump(struct tcf_proto *tp, void *n, struct tcf_walker *arg)
        struct tcf_dump_args *a = (void *)arg;
        struct net *net = sock_net(a->skb->sk);
 
-       return tcf_fill_node(net, a->skb, tp, a->q, a->parent,
+       return tcf_fill_node(net, a->skb, tp, a->block, a->q, a->parent,
                             n, NETLINK_CB(a->cb->skb).portid,
                             a->cb->nlh->nlmsg_seq, NLM_F_MULTI,
                             RTM_NEWTFILTER);
@@ -1223,6 +1246,7 @@ static bool tcf_chain_dump(struct tcf_chain *chain, struct Qdisc *q, u32 parent,
                           long index_start, long *p_index)
 {
        struct net *net = sock_net(skb->sk);
+       struct tcf_block *block = chain->block;
        struct tcmsg *tcm = nlmsg_data(cb->nlh);
        struct tcf_dump_args arg;
        struct tcf_proto *tp;
@@ -1241,7 +1265,7 @@ static bool tcf_chain_dump(struct tcf_chain *chain, struct Qdisc *q, u32 parent,
                        memset(&cb->args[1], 0,
                               sizeof(cb->args) - sizeof(cb->args[0]));
                if (cb->args[1] == 0) {
-                       if (tcf_fill_node(net, skb, tp, q, parent, 0,
+                       if (tcf_fill_node(net, skb, tp, block, q, parent, 0,
                                          NETLINK_CB(cb->skb).portid,
                                          cb->nlh->nlmsg_seq, NLM_F_MULTI,
                                          RTM_NEWTFILTER) <= 0)
@@ -1254,6 +1278,7 @@ static bool tcf_chain_dump(struct tcf_chain *chain, struct Qdisc *q, u32 parent,
                arg.w.fn = tcf_node_dump;
                arg.skb = skb;
                arg.cb = cb;
+               arg.block = block;
                arg.q = q;
                arg.parent = parent;
                arg.w.stop = 0;
@@ -1272,13 +1297,10 @@ static int tc_dump_tfilter(struct sk_buff *skb, struct netlink_callback *cb)
 {
        struct net *net = sock_net(skb->sk);
        struct nlattr *tca[TCA_MAX + 1];
-       struct net_device *dev;
-       struct Qdisc *q;
+       struct Qdisc *q = NULL;
        struct tcf_block *block;
        struct tcf_chain *chain;
        struct tcmsg *tcm = nlmsg_data(cb->nlh);
-       unsigned long cl = 0;
-       const struct Qdisc_class_ops *cops;
        long index_start;
        long index;
        u32 parent;
@@ -1291,32 +1313,44 @@ static int tc_dump_tfilter(struct sk_buff *skb, struct netlink_callback *cb)
        if (err)
                return err;
 
-       dev = __dev_get_by_index(net, tcm->tcm_ifindex);
-       if (!dev)
-               return skb->len;
-
-       parent = tcm->tcm_parent;
-       if (!parent) {
-               q = dev->qdisc;
-               parent = q->handle;
+       if (tcm->tcm_ifindex == TCM_IFINDEX_MAGIC_BLOCK) {
+               block = tcf_block_lookup(net, tcm->tcm_block_index);
+               if (!block)
+                       goto out;
        } else {
-               q = qdisc_lookup(dev, TC_H_MAJ(tcm->tcm_parent));
-       }
-       if (!q)
-               goto out;
-       cops = q->ops->cl_ops;
-       if (!cops)
-               goto out;
-       if (!cops->tcf_block)
-               goto out;
-       if (TC_H_MIN(tcm->tcm_parent)) {
-               cl = cops->find(q, tcm->tcm_parent);
-               if (cl == 0)
+               const struct Qdisc_class_ops *cops;
+               struct net_device *dev;
+               unsigned long cl = 0;
+
+               dev = __dev_get_by_index(net, tcm->tcm_ifindex);
+               if (!dev)
+                       return skb->len;
+
+               parent = tcm->tcm_parent;
+               if (!parent) {
+                       q = dev->qdisc;
+                       parent = q->handle;
+               } else {
+                       q = qdisc_lookup(dev, TC_H_MAJ(tcm->tcm_parent));
+               }
+               if (!q)
                        goto out;
+               cops = q->ops->cl_ops;
+               if (!cops)
+                       goto out;
+               if (!cops->tcf_block)
+                       goto out;
+               if (TC_H_MIN(tcm->tcm_parent)) {
+                       cl = cops->find(q, tcm->tcm_parent);
+                       if (cl == 0)
+                               goto out;
+               }
+               block = cops->tcf_block(q, cl, NULL);
+               if (!block)
+                       goto out;
+               if (tcf_block_shared(block))
+                       q = NULL;
        }
-       block = cops->tcf_block(q, cl, NULL);
-       if (!block)
-               goto out;
 
        index_start = cb->args[0];
        index = 0;