[NET_SCHED]: sch_sfq: add support for external classifiers

Add support for external classifiers to allow using different flow
hash functions similar to ESFQ. When no classifier is attached the
built-in hash is used as before.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 91 insertions, 4 deletions

diff --git a/net/sched/sch_sfq.c b/net/sched/sch_sfq.c
index 91af539ab6e6..d818d1985cca 100644
--- a/net/sched/sch_sfq.c
+++ b/net/sched/sch_sfq.c
@@ -95,6 +95,7 @@ struct sfq_sched_data
         int             limit;
 
 /* Variables */
+        struct tcf_proto *filter_list;
         struct timer_list perturb_timer;
         u32             perturbation;
         sfq_index       tail;           /* Index of current slot in round */
@@ -155,6 +156,39 @@ static unsigned sfq_hash(struct sfq_sched_data *q, struct sk_buff *skb)
         return sfq_fold_hash(q, h, h2);
 }
 
+static unsigned int sfq_classify(struct sk_buff *skb, struct Qdisc *sch,
+                                 int *qerr)
+{
+        struct sfq_sched_data *q = qdisc_priv(sch);
+        struct tcf_result res;
+        int result;
+
+        if (TC_H_MAJ(skb->priority) == sch->handle &&
+            TC_H_MIN(skb->priority) > 0 &&
+            TC_H_MIN(skb->priority) <= SFQ_HASH_DIVISOR)
+                return TC_H_MIN(skb->priority);
+
+        if (!q->filter_list)
+                return sfq_hash(q, skb) + 1;
+
+        *qerr = NET_XMIT_BYPASS;
+        result = tc_classify(skb, q->filter_list, &res);
+        if (result >= 0) {
+#ifdef CONFIG_NET_CLS_ACT
+                switch (result) {
+                case TC_ACT_STOLEN:
+                case TC_ACT_QUEUED:
+                        *qerr = NET_XMIT_SUCCESS;
+                case TC_ACT_SHOT:
+                        return 0;
+                }
+#endif
+                if (TC_H_MIN(res.classid) <= SFQ_HASH_DIVISOR)
+                        return TC_H_MIN(res.classid);
+        }
+        return 0;
+}
+
 static inline void sfq_link(struct sfq_sched_data *q, sfq_index x)
 {
         sfq_index p, n;
@@ -245,8 +279,18 @@ static int
 sfq_enqueue(struct sk_buff *skb, struct Qdisc *sch)
 {
         struct sfq_sched_data *q = qdisc_priv(sch);
-        unsigned hash = sfq_hash(q, skb);
+        unsigned int hash;
         sfq_index x;
+        int ret;
+
+        hash = sfq_classify(skb, sch, &ret);
+        if (hash == 0) {
+                if (ret == NET_XMIT_BYPASS)
+                        sch->qstats.drops++;
+                kfree_skb(skb);
+                return ret;
+        }
+        hash--;
 
         x = q->ht[hash];
         if (x == SFQ_DEPTH) {
@@ -289,8 +333,18 @@ static int
 sfq_requeue(struct sk_buff *skb, struct Qdisc *sch)
 {
         struct sfq_sched_data *q = qdisc_priv(sch);
-        unsigned hash = sfq_hash(q, skb);
+        unsigned int hash;
         sfq_index x;
+        int ret;
+
+        hash = sfq_classify(skb, sch, &ret);
+        if (hash == 0) {
+                if (ret == NET_XMIT_BYPASS)
+                        sch->qstats.drops++;
+                kfree_skb(skb);
+                return ret;
+        }
+        hash--;
 
         x = q->ht[hash];
         if (x == SFQ_DEPTH) {
@@ -465,6 +519,8 @@ static int sfq_init(struct Qdisc *sch, struct nlattr *opt)
 static void sfq_destroy(struct Qdisc *sch)
 {
         struct sfq_sched_data *q = qdisc_priv(sch);
+
+        tcf_destroy_chain(q->filter_list);
         del_timer(&q->perturb_timer);
 }
 
@@ -490,9 +546,40 @@ nla_put_failure:
         return -1;
 }
 
+static int sfq_change_class(struct Qdisc *sch, u32 classid, u32 parentid,
+                            struct nlattr **tca, unsigned long *arg)
+{
+        return -EOPNOTSUPP;
+}
+
+static unsigned long sfq_get(struct Qdisc *sch, u32 classid)
+{
+        return 0;
+}
+
+static struct tcf_proto **sfq_find_tcf(struct Qdisc *sch, unsigned long cl)
+{
+        struct sfq_sched_data *q = qdisc_priv(sch);
+
+        if (cl)
+                return NULL;
+        return &q->filter_list;
+}
+
+static void sfq_walk(struct Qdisc *sch, struct qdisc_walker *arg)
+{
+        return;
+}
+
+static const struct Qdisc_class_ops sfq_class_ops = {
+        .get            =       sfq_get,
+        .change         =       sfq_change_class,
+        .tcf_chain      =       sfq_find_tcf,
+        .walk           =       sfq_walk,
+};
+
 static struct Qdisc_ops sfq_qdisc_ops __read_mostly = {
-        .next           =       NULL,
-        .cl_ops         =       NULL,
+        .cl_ops         =       &sfq_class_ops,
         .id             =       "sfq",
         .priv_size      =       sizeof(struct sfq_sched_data),
         .enqueue        =       sfq_enqueue,