Merge branch 'act_pedit-minor-improvements'

Pedro Tammela says:

====================
net/sched: act_pedit: minor improvements

This series aims to improve the code and usability of act_pedit for
netlink users.

Patches 1-2 improves error reporting for extended keys parsing with extack.

Patch 3 checks the static offsets a priori on create/update. Currently,
this is done at the datapath for both static and runtime offsets.

Patch 4 removes a check from the datapath which is redundant since the
netlink parsing validates the key types.

Patch 5 changes the 'pr_info()' calls in the datapath to rate limited
versions.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

net/sched/act_pedit.c

@@ -30,12 +30,13 @@ static const struct nla_policy pedit_policy[TCA_PEDIT_MAX + 1] = {
 };
 
 static const struct nla_policy pedit_key_ex_policy[TCA_PEDIT_KEY_EX_MAX + 1] = {
-	[TCA_PEDIT_KEY_EX_HTYPE]  = { .type = NLA_U16 },
-	[TCA_PEDIT_KEY_EX_CMD]	  = { .type = NLA_U16 },
+	[TCA_PEDIT_KEY_EX_HTYPE] =
+		NLA_POLICY_MAX(NLA_U16, TCA_PEDIT_HDR_TYPE_MAX),
+	[TCA_PEDIT_KEY_EX_CMD] = NLA_POLICY_MAX(NLA_U16, TCA_PEDIT_CMD_MAX),
 };
 
 static struct tcf_pedit_key_ex *tcf_pedit_keys_ex_parse(struct nlattr *nla,
-							u8 n)
+							u8 n, struct netlink_ext_ack *extack)
 {
 	struct tcf_pedit_key_ex *keys_ex;
 	struct tcf_pedit_key_ex *k;
@@ -56,12 +57,14 @@ static struct tcf_pedit_key_ex *tcf_pedit_keys_ex_parse(struct nlattr *nla,
 		struct nlattr *tb[TCA_PEDIT_KEY_EX_MAX + 1];
 
 		if (!n) {
+			NL_SET_ERR_MSG_MOD(extack, "Can't parse more extended keys than requested");
 			err = -EINVAL;
 			goto err_out;
 		}
 		n--;
 
 		if (nla_type(ka) != TCA_PEDIT_KEY_EX) {
+			NL_SET_ERR_MSG_ATTR(extack, ka, "Unknown attribute, expected extended key");
 			err = -EINVAL;
 			goto err_out;
 		}
@@ -72,25 +75,26 @@ static struct tcf_pedit_key_ex *tcf_pedit_keys_ex_parse(struct nlattr *nla,
 		if (err)
 			goto err_out;
 
-		if (!tb[TCA_PEDIT_KEY_EX_HTYPE] ||
-		    !tb[TCA_PEDIT_KEY_EX_CMD]) {
+		if (NL_REQ_ATTR_CHECK(extack, nla, tb, TCA_PEDIT_KEY_EX_HTYPE)) {
+			NL_SET_ERR_MSG(extack, "Missing required attribute");
 			err = -EINVAL;
 			goto err_out;
 		}
 
-		k->htype = nla_get_u16(tb[TCA_PEDIT_KEY_EX_HTYPE]);
-		k->cmd = nla_get_u16(tb[TCA_PEDIT_KEY_EX_CMD]);
-
-		if (k->htype > TCA_PEDIT_HDR_TYPE_MAX ||
-		    k->cmd > TCA_PEDIT_CMD_MAX) {
+		if (NL_REQ_ATTR_CHECK(extack, nla, tb, TCA_PEDIT_KEY_EX_CMD)) {
+			NL_SET_ERR_MSG(extack, "Missing required attribute");
 			err = -EINVAL;
 			goto err_out;
 		}
 
+		k->htype = nla_get_u16(tb[TCA_PEDIT_KEY_EX_HTYPE]);
+		k->cmd = nla_get_u16(tb[TCA_PEDIT_KEY_EX_CMD]);
+
 		k++;
 	}
 
 	if (n) {
+		NL_SET_ERR_MSG_MOD(extack, "Not enough extended keys to parse");
 		err = -EINVAL;
 		goto err_out;
 	}
@@ -222,7 +226,7 @@ static int tcf_pedit_init(struct net *net, struct nlattr *nla,
 	}
 
 	nparms->tcfp_keys_ex =
-		tcf_pedit_keys_ex_parse(tb[TCA_PEDIT_KEYS_EX], parm->nkeys);
+		tcf_pedit_keys_ex_parse(tb[TCA_PEDIT_KEYS_EX], parm->nkeys, extack);
 	if (IS_ERR(nparms->tcfp_keys_ex)) {
 		ret = PTR_ERR(nparms->tcfp_keys_ex);
 		goto out_free;
@@ -247,8 +251,16 @@ static int tcf_pedit_init(struct net *net, struct nlattr *nla,
 	memcpy(nparms->tcfp_keys, parm->keys, ksize);
 
 	for (i = 0; i < nparms->tcfp_nkeys; ++i) {
+		u32 offmask = nparms->tcfp_keys[i].offmask;
 		u32 cur = nparms->tcfp_keys[i].off;
 
+		/* The AT option can be added to static offsets in the datapath */
+		if (!offmask && cur % 4) {
+			NL_SET_ERR_MSG_MOD(extack, "Offsets must be on 32bit boundaries");
+			ret = -EINVAL;
+			goto put_chain;
+		}
+
 		/* sanitize the shift value for any later use */
 		nparms->tcfp_keys[i].shift = min_t(size_t,
 						   BITS_PER_TYPE(int) - 1,
@@ -257,7 +269,7 @@ static int tcf_pedit_init(struct net *net, struct nlattr *nla,
 		/* The AT option can read a single byte, we can bound the actual
 		 * value with uchar max.
 		 */
-		cur += (0xff & nparms->tcfp_keys[i].offmask) >> nparms->tcfp_keys[i].shift;
+		cur += (0xff & offmask) >> nparms->tcfp_keys[i].shift;
 
 		/* Each key touches 4 bytes starting from the computed offset */
 		nparms->tcfp_off_max_hint =
@@ -313,37 +325,28 @@ static bool offset_valid(struct sk_buff *skb, int offset)
 	return true;
 }
 
-static int pedit_skb_hdr_offset(struct sk_buff *skb,
-				enum pedit_header_type htype, int *hoffset)
+static void pedit_skb_hdr_offset(struct sk_buff *skb,
+				 enum pedit_header_type htype, int *hoffset)
 {
-	int ret = -EINVAL;
-
+	/* 'htype' is validated in the netlink parsing */
 	switch (htype) {
 	case TCA_PEDIT_KEY_EX_HDR_TYPE_ETH:
-		if (skb_mac_header_was_set(skb)) {
+		if (skb_mac_header_was_set(skb))
 			*hoffset = skb_mac_offset(skb);
-			ret = 0;
-		}
 		break;
 	case TCA_PEDIT_KEY_EX_HDR_TYPE_NETWORK:
 	case TCA_PEDIT_KEY_EX_HDR_TYPE_IP4:
 	case TCA_PEDIT_KEY_EX_HDR_TYPE_IP6:
 		*hoffset = skb_network_offset(skb);
-		ret = 0;
 		break;
 	case TCA_PEDIT_KEY_EX_HDR_TYPE_TCP:
 	case TCA_PEDIT_KEY_EX_HDR_TYPE_UDP:
-		if (skb_transport_header_was_set(skb)) {
+		if (skb_transport_header_was_set(skb))
 			*hoffset = skb_transport_offset(skb);
-			ret = 0;
-		}
 		break;
 	default:
-		ret = -EINVAL;
 		break;
 	}
-
-	return ret;
 }
 
 TC_INDIRECT_SCOPE int tcf_pedit_act(struct sk_buff *skb,
@@ -376,10 +379,9 @@ TC_INDIRECT_SCOPE int tcf_pedit_act(struct sk_buff *skb,
 
 	for (i = parms->tcfp_nkeys; i > 0; i--, tkey++) {
 		int offset = tkey->off;
+		int hoffset = 0;
 		u32 *ptr, hdata;
-		int hoffset;
 		u32 val;
-		int rc;
 
 		if (tkey_ex) {
 			htype = tkey_ex->htype;
@@ -388,36 +390,30 @@ TC_INDIRECT_SCOPE int tcf_pedit_act(struct sk_buff *skb,
 			tkey_ex++;
 		}
 
-		rc = pedit_skb_hdr_offset(skb, htype, &hoffset);
-		if (rc) {
-			pr_info("tc action pedit bad header type specified (0x%x)\n",
-				htype);
-			goto bad;
-		}
+		pedit_skb_hdr_offset(skb, htype, &hoffset);
 
 		if (tkey->offmask) {
 			u8 *d, _d;
 
 			if (!offset_valid(skb, hoffset + tkey->at)) {
-				pr_info("tc action pedit 'at' offset %d out of bounds\n",
-					hoffset + tkey->at);
+				pr_info_ratelimited("tc action pedit 'at' offset %d out of bounds\n",
+						    hoffset + tkey->at);
 				goto bad;
 			}
 			d = skb_header_pointer(skb, hoffset + tkey->at,
 					       sizeof(_d), &_d);
 			if (!d)
 				goto bad;
-			offset += (*d & tkey->offmask) >> tkey->shift;
-		}
 
-		if (offset % 4) {
-			pr_info("tc action pedit offset must be on 32 bit boundaries\n");
-			goto bad;
+			offset += (*d & tkey->offmask) >> tkey->shift;
+			if (offset % 4) {
+				pr_info_ratelimited("tc action pedit offset must be on 32 bit boundaries\n");
+				goto bad;
+			}
 		}
 
 		if (!offset_valid(skb, hoffset + offset)) {
-			pr_info("tc action pedit offset %d out of bounds\n",
-				hoffset + offset);
+			pr_info_ratelimited("tc action pedit offset %d out of bounds\n", hoffset + offset);
 			goto bad;
 		}
 
@@ -434,8 +430,7 @@ TC_INDIRECT_SCOPE int tcf_pedit_act(struct sk_buff *skb,
 			val = (*ptr + tkey->val) & ~tkey->mask;
 			break;
 		default:
-			pr_info("tc action pedit bad command (%d)\n",
-				cmd);
+			pr_info_ratelimited("tc action pedit bad command (%d)\n", cmd);
 			goto bad;
 		}