[NET_SCHED]: act_api: qdisc internal reclassify support

The behaviour of NET_CLS_POLICE for TC_POLICE_RECLASSIFY was to return
it to the qdisc, which could handle it internally or ignore it. With
NET_CLS_ACT however, tc_classify starts over at the first classifier
and never returns it to the qdisc. This makes it impossible to support
qdisc-internal reclassification, which in turn makes it impossible to
remove the old NET_CLS_POLICE code without breaking compatibility since
we have two qdiscs (CBQ and ATM) that support this.

This patch adds a tc_classify_compat function that handles
reclassification the old way and changes CBQ and ATM to use it.

This again is of course not fully backwards compatible with the previous
NET_CLS_ACT behaviour. Unfortunately there is no way to fully maintain
compatibility *and* support qdisc internal reclassification with
NET_CLS_ACT, but this seems like the better choice over keeping the two
incompatible options around forever.

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

4 files changed, 69 insertions, 50 deletions

diff --git a/net/sched/sch_api.c b/net/sched/sch_api.c
index 4fd0beca9450..13c09bc32aa3 100644
--- a/net/sched/sch_api.c
+++ b/net/sched/sch_api.c
@@ -1145,47 +1145,57 @@ static int tc_dump_tclass(struct sk_buff *skb, struct netlink_callback *cb)
    to this qdisc, (optionally) tests for protocol and asks
    specific classifiers.
  */
+int tc_classify_compat(struct sk_buff *skb, struct tcf_proto *tp,
+                       struct tcf_result *res)
+{
+        __be16 protocol = skb->protocol;
+        int err = 0;
+
+        for (; tp; tp = tp->next) {
+                if ((tp->protocol == protocol ||
+                     tp->protocol == htons(ETH_P_ALL)) &&
+                    (err = tp->classify(skb, tp, res)) >= 0) {
+#ifdef CONFIG_NET_CLS_ACT
+                        if (err != TC_ACT_RECLASSIFY && skb->tc_verd)
+                                skb->tc_verd = SET_TC_VERD(skb->tc_verd, 0);
+#endif
+                        return err;
+                }
+        }
+        return -1;
+}
+EXPORT_SYMBOL(tc_classify_compat);
+
 int tc_classify(struct sk_buff *skb, struct tcf_proto *tp,
-        struct tcf_result *res)
+                struct tcf_result *res)
 {
         int err = 0;
-        __be16 protocol = skb->protocol;
+        __be16 protocol;
 #ifdef CONFIG_NET_CLS_ACT
         struct tcf_proto *otp = tp;
 reclassify:
 #endif
         protocol = skb->protocol;
 
-        for ( ; tp; tp = tp->next) {
-                if ((tp->protocol == protocol ||
-                        tp->protocol == htons(ETH_P_ALL)) &&
-                        (err = tp->classify(skb, tp, res)) >= 0) {
+        err = tc_classify_compat(skb, tp, res);
 #ifdef CONFIG_NET_CLS_ACT
-                        if ( TC_ACT_RECLASSIFY == err) {
-                                __u32 verd = (__u32) G_TC_VERD(skb->tc_verd);
-                                tp = otp;
-
-                                if (MAX_REC_LOOP < verd++) {
-                                        printk("rule prio %d protocol %02x reclassify is buggy packet dropped\n",
-                                                tp->prio&0xffff, ntohs(tp->protocol));
-                                        return TC_ACT_SHOT;
-                                }
-                                skb->tc_verd = SET_TC_VERD(skb->tc_verd,verd);
-                                goto reclassify;
-                        } else {
-                                if (skb->tc_verd)
-                                        skb->tc_verd = SET_TC_VERD(skb->tc_verd,0);
-                                return err;
-                        }
-#else
-
-                        return err;
-#endif
+        if (err == TC_ACT_RECLASSIFY) {
+                u32 verd = G_TC_VERD(skb->tc_verd);
+                tp = otp;
+
+                if (verd++ >= MAX_REC_LOOP) {
+                        printk("rule prio %u protocol %02x reclassify loop, "
+                               "packet dropped\n",
+                               tp->prio&0xffff, ntohs(tp->protocol));
+                        return TC_ACT_SHOT;
                 }
-
+                skb->tc_verd = SET_TC_VERD(skb->tc_verd, verd);
+                goto reclassify;
         }
-        return -1;
+#endif
+        return err;
 }
+EXPORT_SYMBOL(tc_classify);
 
 void tcf_destroy(struct tcf_proto *tp)
 {
@@ -1252,4 +1262,3 @@ EXPORT_SYMBOL(qdisc_get_rtab);
 EXPORT_SYMBOL(qdisc_put_rtab);
 EXPORT_SYMBOL(register_qdisc);
 EXPORT_SYMBOL(unregister_qdisc);
-EXPORT_SYMBOL(tc_classify);
diff --git a/net/sched/sch_atm.c b/net/sched/sch_atm.c
index ccee10dae66d..37ae6d1deb14 100644
--- a/net/sched/sch_atm.c
+++ b/net/sched/sch_atm.c
@@ -396,8 +396,9 @@ static int atm_tc_enqueue(struct sk_buff *skb, struct Qdisc *sch)
             !(flow = (struct atm_flow_data *)atm_tc_get(sch, skb->priority)))
                 for (flow = p->flows; flow; flow = flow->next)
                         if (flow->filter_list) {
-                                result = tc_classify(skb, flow->filter_list,
-                                                     &res);
+                                result = tc_classify_compat(skb,
+                                                            flow->filter_list,
+                                                            &res);
                                 if (result < 0)
                                         continue;
                                 flow = (struct atm_flow_data *)res.class;
@@ -420,6 +421,12 @@ static int atm_tc_enqueue(struct sk_buff *skb, struct Qdisc *sch)
                 case TC_ACT_SHOT:
                         kfree_skb(skb);
                         goto drop;
+                case TC_POLICE_RECLASSIFY:
+                        if (flow->excess)
+                                flow = flow->excess;
+                        else
+                                ATM_SKB(skb)->atm_options |= ATM_ATMOPT_CLP;
+                        break;
                 }
 #elif defined(CONFIG_NET_CLS_POLICE)
                 switch (result) {
diff --git a/net/sched/sch_cbq.c b/net/sched/sch_cbq.c
index b184c3545145..77381f1c6541 100644
--- a/net/sched/sch_cbq.c
+++ b/net/sched/sch_cbq.c
@@ -82,7 +82,7 @@ struct cbq_class
         unsigned char           priority2;      /* priority to be used after overlimit */
         unsigned char           ewma_log;       /* time constant for idle time calculation */
         unsigned char           ovl_strategy;
-#ifdef CONFIG_NET_CLS_POLICE
+#if defined(CONFIG_NET_CLS_ACT) || defined(CONFIG_NET_CLS_POLICE)
         unsigned char           police;
 #endif
 
@@ -154,7 +154,7 @@ struct cbq_sched_data
         struct cbq_class        *active[TC_CBQ_MAXPRIO+1];      /* List of all classes
                                                                    with backlog */
 
-#ifdef CONFIG_NET_CLS_POLICE
+#if defined(CONFIG_NET_CLS_ACT) || defined(CONFIG_NET_CLS_POLICE)
         struct cbq_class        *rx_class;
 #endif
         struct cbq_class        *tx_class;
@@ -196,7 +196,7 @@ cbq_class_lookup(struct cbq_sched_data *q, u32 classid)
         return NULL;
 }
 
-#ifdef CONFIG_NET_CLS_POLICE
+#if defined(CONFIG_NET_CLS_ACT) || defined(CONFIG_NET_CLS_POLICE)
 
 static struct cbq_class *
 cbq_reclassify(struct sk_buff *skb, struct cbq_class *this)
@@ -247,7 +247,8 @@ cbq_classify(struct sk_buff *skb, struct Qdisc *sch, int *qerr)
                 /*
                  * Step 2+n. Apply classifier.
                  */
-                if (!head->filter_list || (result = tc_classify(skb, head->filter_list, &res)) < 0)
+                if (!head->filter_list ||
+                    (result = tc_classify_compat(skb, head->filter_list, &res)) < 0)
                         goto fallback;
 
                 if ((cl = (void*)res.class) == NULL) {
@@ -267,6 +268,8 @@ cbq_classify(struct sk_buff *skb, struct Qdisc *sch, int *qerr)
                         *qerr = NET_XMIT_SUCCESS;
                 case TC_ACT_SHOT:
                         return NULL;
+                case TC_ACT_RECLASSIFY:
+                        return cbq_reclassify(skb, cl);
                 }
 #elif defined(CONFIG_NET_CLS_POLICE)
                 switch (result) {
@@ -389,7 +392,7 @@ cbq_enqueue(struct sk_buff *skb, struct Qdisc *sch)
         int ret;
         struct cbq_class *cl = cbq_classify(skb, sch, &ret);
 
-#ifdef CONFIG_NET_CLS_POLICE
+#if defined(CONFIG_NET_CLS_ACT) || defined(CONFIG_NET_CLS_POLICE)
         q->rx_class = cl;
 #endif
         if (cl == NULL) {
@@ -399,7 +402,7 @@ cbq_enqueue(struct sk_buff *skb, struct Qdisc *sch)
                 return ret;
         }
 
-#ifdef CONFIG_NET_CLS_POLICE
+#if defined(CONFIG_NET_CLS_ACT) || defined(CONFIG_NET_CLS_POLICE)
         cl->q->__parent = sch;
 #endif
         if ((ret = cl->q->enqueue(skb, cl->q)) == NET_XMIT_SUCCESS) {
@@ -434,7 +437,7 @@ cbq_requeue(struct sk_buff *skb, struct Qdisc *sch)
 
         cbq_mark_toplevel(q, cl);
 
-#ifdef CONFIG_NET_CLS_POLICE
+#if defined(CONFIG_NET_CLS_ACT) || defined(CONFIG_NET_CLS_POLICE)
         q->rx_class = cl;
         cl->q->__parent = sch;
 #endif
@@ -670,7 +673,7 @@ static enum hrtimer_restart cbq_undelay(struct hrtimer *timer)
 }
 
 
-#ifdef CONFIG_NET_CLS_POLICE
+#if defined(CONFIG_NET_CLS_ACT) || defined(CONFIG_NET_CLS_POLICE)
 
 static int cbq_reshape_fail(struct sk_buff *skb, struct Qdisc *child)
 {
@@ -1364,7 +1367,7 @@ static int cbq_set_overlimit(struct cbq_class *cl, struct tc_cbq_ovl *ovl)
         return 0;
 }
 
-#ifdef CONFIG_NET_CLS_POLICE
+#if defined(CONFIG_NET_CLS_ACT) || defined(CONFIG_NET_CLS_POLICE)
 static int cbq_set_police(struct cbq_class *cl, struct tc_cbq_police *p)
 {
         cl->police = p->police;
@@ -1532,7 +1535,7 @@ rtattr_failure:
         return -1;
 }
 
-#ifdef CONFIG_NET_CLS_POLICE
+#if defined(CONFIG_NET_CLS_ACT) || defined(CONFIG_NET_CLS_POLICE)
 static __inline__ int cbq_dump_police(struct sk_buff *skb, struct cbq_class *cl)
 {
         unsigned char *b = skb_tail_pointer(skb);
@@ -1558,7 +1561,7 @@ static int cbq_dump_attr(struct sk_buff *skb, struct cbq_class *cl)
             cbq_dump_rate(skb, cl) < 0 ||
             cbq_dump_wrr(skb, cl) < 0 ||
             cbq_dump_ovl(skb, cl) < 0 ||
-#ifdef CONFIG_NET_CLS_POLICE
+#if defined(CONFIG_NET_CLS_ACT) || defined(CONFIG_NET_CLS_POLICE)
             cbq_dump_police(skb, cl) < 0 ||
 #endif
             cbq_dump_fopt(skb, cl) < 0)
@@ -1653,7 +1656,7 @@ static int cbq_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new,
                                                      cl->classid)) == NULL)
                                 return -ENOBUFS;
                 } else {
-#ifdef CONFIG_NET_CLS_POLICE
+#if defined(CONFIG_NET_CLS_ACT) || defined(CONFIG_NET_CLS_POLICE)
                         if (cl->police == TC_POLICE_RECLASSIFY)
                                 new->reshape_fail = cbq_reshape_fail;
 #endif
@@ -1718,7 +1721,7 @@ cbq_destroy(struct Qdisc* sch)
         struct cbq_class *cl;
         unsigned h;
 
-#ifdef CONFIG_NET_CLS_POLICE
+#if defined(CONFIG_NET_CLS_ACT) || defined(CONFIG_NET_CLS_POLICE)
         q->rx_class = NULL;
 #endif
         /*
@@ -1747,7 +1750,7 @@ static void cbq_put(struct Qdisc *sch, unsigned long arg)
         struct cbq_class *cl = (struct cbq_class*)arg;
 
         if (--cl->refcnt == 0) {
-#ifdef CONFIG_NET_CLS_POLICE
+#if defined(CONFIG_NET_CLS_ACT) || defined(CONFIG_NET_CLS_POLICE)
                 struct cbq_sched_data *q = qdisc_priv(sch);
 
                 spin_lock_bh(&sch->dev->queue_lock);
@@ -1795,7 +1798,7 @@ cbq_change_class(struct Qdisc *sch, u32 classid, u32 parentid, struct rtattr **t
             RTA_PAYLOAD(tb[TCA_CBQ_WRROPT-1]) < sizeof(struct tc_cbq_wrropt))
                         return -EINVAL;
 
-#ifdef CONFIG_NET_CLS_POLICE
+#if defined(CONFIG_NET_CLS_ACT) || defined(CONFIG_NET_CLS_POLICE)
         if (tb[TCA_CBQ_POLICE-1] &&
             RTA_PAYLOAD(tb[TCA_CBQ_POLICE-1]) < sizeof(struct tc_cbq_police))
                         return -EINVAL;
@@ -1838,7 +1841,7 @@ cbq_change_class(struct Qdisc *sch, u32 classid, u32 parentid, struct rtattr **t
                 if (tb[TCA_CBQ_OVL_STRATEGY-1])
                         cbq_set_overlimit(cl, RTA_DATA(tb[TCA_CBQ_OVL_STRATEGY-1]));
 
-#ifdef CONFIG_NET_CLS_POLICE
+#if defined(CONFIG_NET_CLS_ACT) || defined(CONFIG_NET_CLS_POLICE)
                 if (tb[TCA_CBQ_POLICE-1])
                         cbq_set_police(cl, RTA_DATA(tb[TCA_CBQ_POLICE-1]));
 #endif
@@ -1931,7 +1934,7 @@ cbq_change_class(struct Qdisc *sch, u32 classid, u32 parentid, struct rtattr **t
         cl->overlimit = cbq_ovl_classic;
         if (tb[TCA_CBQ_OVL_STRATEGY-1])
                 cbq_set_overlimit(cl, RTA_DATA(tb[TCA_CBQ_OVL_STRATEGY-1]));
-#ifdef CONFIG_NET_CLS_POLICE
+#if defined(CONFIG_NET_CLS_ACT) || defined(CONFIG_NET_CLS_POLICE)
         if (tb[TCA_CBQ_POLICE-1])
                 cbq_set_police(cl, RTA_DATA(tb[TCA_CBQ_POLICE-1]));
 #endif
@@ -1975,7 +1978,7 @@ static int cbq_delete(struct Qdisc *sch, unsigned long arg)
                 q->tx_class = NULL;
                 q->tx_borrowed = NULL;
         }
-#ifdef CONFIG_NET_CLS_POLICE
+#if defined(CONFIG_NET_CLS_ACT) || defined(CONFIG_NET_CLS_POLICE)
         if (q->rx_class == cl)
                 q->rx_class = NULL;
 #endif
diff --git a/net/sched/sch_tbf.c b/net/sched/sch_tbf.c
index 22e431dace54..b8b3345cede8 100644
--- a/net/sched/sch_tbf.c
+++ b/net/sched/sch_tbf.c
@@ -125,7 +125,7 @@ static int tbf_enqueue(struct sk_buff *skb, struct Qdisc* sch)
 
         if (skb->len > q->max_size) {
                 sch->qstats.drops++;
-#ifdef CONFIG_NET_CLS_POLICE
+#if defined(CONFIG_NET_CLS_ACT) || defined(CONFIG_NET_CLS_POLICE)
                 if (sch->reshape_fail == NULL || sch->reshape_fail(skb, sch))
 #endif
                         kfree_skb(skb);