Merge branch 'act_pedit-relative-offset'

Amir Vadai says:

====================
net/sched: act_pedit: Use offset relative to conventional network headers

Some FW/HW parser APIs are such that they need to get the specific header type (e.g
IPV4 or IPV6, TCP or UDP) and not only the networking level (e.g network or transport).

Enhancing the UAPI to allow for specifying that, would allow the same flows to be
set into both SW and HW.

This patchset also makes pedit more robust. Currently fields offset is specified
by offset relative to the ip header, while using negative offsets for
MAC layer fields.

This series enables the user to set offset relative to the relevant header.

Usage example:
$ tc filter add dev enp0s9 protocol ip parent ffff: \
   flower \
     ip_proto tcp \
    dst_port 80 \
   action \
       pedit munge ip ttl add 0xff \
       pedit munge tcp dport set 8080 \
     pipe action mirred egress redirect dev veth0

Will forward traffic destined to tcp dport 80, while modifying the
destination port to 8080, and decreasing the ttl by one.

I've uploaded a draft for the userspace [2] to make it easier to review and
test the patchset.

[1] - http://patchwork.ozlabs.org/patch/700909/
[2] - git: https://bitbucket.org/av42/iproute2.git
      branch: pedit

Patchset was tested and applied on top of upstream commit bd092ad1 ("Merge
branch 'remove-__napi_complete_done'")

Thanks,
Amir

Changes since V2:
- Instead of reusing unused bits in existing uapi fields, using new netlink
	attributes for the new information. This way new/old user space and new/old
	kernel can live together without having misunderstandings.

Changes since V1:
- No changes - V1 was sent and didn't make it for 4.10.
- You asked me [1] why did I use specific header names instead of layers (L2,
	L3...), and I explained that it is on purpose, this extra information is
	planned to be used by hardware drivers to offload the action.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

include/linux/skbuff.h

@@ -2184,6 +2184,11 @@ static inline unsigned char *skb_mac_header(const struct sk_buff *skb)
 	return skb->head + skb->mac_header;
 }
 
+static inline int skb_mac_offset(const struct sk_buff *skb)
+{
+	return skb_mac_header(skb) - skb->data;
+}
+
 static inline int skb_mac_header_was_set(const struct sk_buff *skb)
 {
 	return skb->mac_header != (typeof(skb->mac_header))~0U;

include/net/tc_act/tc_pedit.h

@@ -3,11 +3,17 @@
 
 #include <net/act_api.h>
 
+struct tcf_pedit_key_ex {
+	enum pedit_header_type htype;
+	enum pedit_cmd cmd;
+};
+
 struct tcf_pedit {
 	struct tc_action	common;
 	unsigned char		tcfp_nkeys;
 	unsigned char		tcfp_flags;
 	struct tc_pedit_key	*tcfp_keys;
+	struct tcf_pedit_key_ex	*tcfp_keys_ex;
 };
 #define to_pedit(a) ((struct tcf_pedit *)a)
 

include/uapi/linux/tc_act/tc_pedit.h

@@ -11,10 +11,41 @@ enum {
 	TCA_PEDIT_TM,
 	TCA_PEDIT_PARMS,
 	TCA_PEDIT_PAD,
+	TCA_PEDIT_PARMS_EX,
+	TCA_PEDIT_KEYS_EX,
+	TCA_PEDIT_KEY_EX,
 	__TCA_PEDIT_MAX
 };
 #define TCA_PEDIT_MAX (__TCA_PEDIT_MAX - 1)
                                                                                 
+enum {
+	TCA_PEDIT_KEY_EX_HTYPE = 1,
+	TCA_PEDIT_KEY_EX_CMD = 2,
+	__TCA_PEDIT_KEY_EX_MAX
+};
+#define TCA_PEDIT_KEY_EX_MAX (__TCA_PEDIT_KEY_EX_MAX - 1)
+
+ /* TCA_PEDIT_KEY_EX_HDR_TYPE_NETWROK is a special case for legacy users. It
+  * means no specific header type - offset is relative to the network layer
+  */
+enum pedit_header_type {
+	TCA_PEDIT_KEY_EX_HDR_TYPE_NETWORK = 0,
+	TCA_PEDIT_KEY_EX_HDR_TYPE_ETH = 1,
+	TCA_PEDIT_KEY_EX_HDR_TYPE_IP4 = 2,
+	TCA_PEDIT_KEY_EX_HDR_TYPE_IP6 = 3,
+	TCA_PEDIT_KEY_EX_HDR_TYPE_TCP = 4,
+	TCA_PEDIT_KEY_EX_HDR_TYPE_UDP = 5,
+	__PEDIT_HDR_TYPE_MAX,
+};
+#define TCA_PEDIT_HDR_TYPE_MAX (__PEDIT_HDR_TYPE_MAX - 1)
+
+enum pedit_cmd {
+	TCA_PEDIT_KEY_EX_CMD_SET = 0,
+	TCA_PEDIT_KEY_EX_CMD_ADD = 1,
+	__PEDIT_CMD_MAX,
+};
+#define TCA_PEDIT_CMD_MAX (__PEDIT_CMD_MAX - 1)
+
 struct tc_pedit_key {
 	__u32           mask;  /* AND */
 	__u32           val;   /*XOR */

net/sched/act_pedit.c

@@ -22,6 +22,7 @@
 #include <net/pkt_sched.h>
 #include <linux/tc_act/tc_pedit.h>
 #include <net/tc_act/tc_pedit.h>
+#include <uapi/linux/tc_act/tc_pedit.h>
 
 #define PEDIT_TAB_MASK	15
 
@@ -30,18 +31,117 @@ static struct tc_action_ops act_pedit_ops;
 
 static const struct nla_policy pedit_policy[TCA_PEDIT_MAX + 1] = {
 	[TCA_PEDIT_PARMS]	= { .len = sizeof(struct tc_pedit) },
+	[TCA_PEDIT_KEYS_EX]   = { .type = NLA_NESTED },
 };
 
+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 },
+};
+
+static struct tcf_pedit_key_ex *tcf_pedit_keys_ex_parse(struct nlattr *nla,
+							u8 n)
+{
+	struct tcf_pedit_key_ex *keys_ex;
+	struct tcf_pedit_key_ex *k;
+	const struct nlattr *ka;
+	int err = -EINVAL;
+	int rem;
+
+	if (!nla || !n)
+		return NULL;
+
+	keys_ex = kcalloc(n, sizeof(*k), GFP_KERNEL);
+	if (!keys_ex)
+		return ERR_PTR(-ENOMEM);
+
+	k = keys_ex;
+
+	nla_for_each_nested(ka, nla, rem) {
+		struct nlattr *tb[TCA_PEDIT_KEY_EX_MAX + 1];
+
+		if (!n) {
+			err = -EINVAL;
+			goto err_out;
+		}
+		n--;
+
+		if (nla_type(ka) != TCA_PEDIT_KEY_EX) {
+			err = -EINVAL;
+			goto err_out;
+		}
+
+		err = nla_parse_nested(tb, TCA_PEDIT_KEY_EX_MAX, ka,
+				       pedit_key_ex_policy);
+		if (err)
+			goto err_out;
+
+		if (!tb[TCA_PEDIT_KEY_EX_HTYPE] ||
+		    !tb[TCA_PEDIT_KEY_EX_CMD]) {
+			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) {
+			err = -EINVAL;
+			goto err_out;
+		}
+
+		k++;
+	}
+
+	if (n)
+		goto err_out;
+
+	return keys_ex;
+
+err_out:
+	kfree(keys_ex);
+	return ERR_PTR(err);
+}
+
+static int tcf_pedit_key_ex_dump(struct sk_buff *skb,
+				 struct tcf_pedit_key_ex *keys_ex, int n)
+{
+	struct nlattr *keys_start = nla_nest_start(skb, TCA_PEDIT_KEYS_EX);
+
+	for (; n > 0; n--) {
+		struct nlattr *key_start;
+
+		key_start = nla_nest_start(skb, TCA_PEDIT_KEY_EX);
+
+		if (nla_put_u16(skb, TCA_PEDIT_KEY_EX_HTYPE, keys_ex->htype) ||
+		    nla_put_u16(skb, TCA_PEDIT_KEY_EX_CMD, keys_ex->cmd)) {
+			nlmsg_trim(skb, keys_start);
+			return -EINVAL;
+		}
+
+		nla_nest_end(skb, key_start);
+
+		keys_ex++;
+	}
+
+	nla_nest_end(skb, keys_start);
+
+	return 0;
+}
+
 static int tcf_pedit_init(struct net *net, struct nlattr *nla,
 			  struct nlattr *est, struct tc_action **a,
 			  int ovr, int bind)
 {
 	struct tc_action_net *tn = net_generic(net, pedit_net_id);
 	struct nlattr *tb[TCA_PEDIT_MAX + 1];
+	struct nlattr *pattr;
 	struct tc_pedit *parm;
 	int ret = 0, err;
 	struct tcf_pedit *p;
 	struct tc_pedit_key *keys = NULL;
+	struct tcf_pedit_key_ex *keys_ex;
 	int ksize;
 
 	if (nla == NULL)
@@ -51,13 +151,21 @@ static int tcf_pedit_init(struct net *net, struct nlattr *nla,
 	if (err < 0)
 		return err;
 
-	if (tb[TCA_PEDIT_PARMS] == NULL)
+	pattr = tb[TCA_PEDIT_PARMS];
+	if (!pattr)
+		pattr = tb[TCA_PEDIT_PARMS_EX];
+	if (!pattr)
 		return -EINVAL;
-	parm = nla_data(tb[TCA_PEDIT_PARMS]);
+
+	parm = nla_data(pattr);
 	ksize = parm->nkeys * sizeof(struct tc_pedit_key);
-	if (nla_len(tb[TCA_PEDIT_PARMS]) < sizeof(*parm) + ksize)
+	if (nla_len(pattr) < sizeof(*parm) + ksize)
 		return -EINVAL;
 
+	keys_ex = tcf_pedit_keys_ex_parse(tb[TCA_PEDIT_KEYS_EX], parm->nkeys);
+	if (IS_ERR(keys_ex))
+		return PTR_ERR(keys_ex);
+
 	if (!tcf_hash_check(tn, parm->index, a, bind)) {
 		if (!parm->nkeys)
 			return -EINVAL;
@@ -69,6 +177,7 @@ static int tcf_pedit_init(struct net *net, struct nlattr *nla,
 		keys = kmalloc(ksize, GFP_KERNEL);
 		if (keys == NULL) {
 			tcf_hash_cleanup(*a, est);
+			kfree(keys_ex);
 			return -ENOMEM;
 		}
 		ret = ACT_P_CREATED;
@@ -81,10 +190,12 @@ static int tcf_pedit_init(struct net *net, struct nlattr *nla,
 		p = to_pedit(*a);
 		if (p->tcfp_nkeys && p->tcfp_nkeys != parm->nkeys) {
 			keys = kmalloc(ksize, GFP_KERNEL);
-			if (keys == NULL)
+			if (!keys) {
+				kfree(keys_ex);
 				return -ENOMEM;
 			}
 		}
+	}
 
 	spin_lock_bh(&p->tcf_lock);
 	p->tcfp_flags = parm->flags;
@@ -95,6 +206,10 @@ static int tcf_pedit_init(struct net *net, struct nlattr *nla,
 		p->tcfp_nkeys = parm->nkeys;
 	}
 	memcpy(p->tcfp_keys, parm->keys, ksize);
+
+	kfree(p->tcfp_keys_ex);
+	p->tcfp_keys_ex = keys_ex;
+
 	spin_unlock_bh(&p->tcf_lock);
 	if (ret == ACT_P_CREATED)
 		tcf_hash_insert(tn, *a);
@@ -106,6 +221,7 @@ static void tcf_pedit_cleanup(struct tc_action *a, int bind)
 	struct tcf_pedit *p = to_pedit(a);
 	struct tc_pedit_key *keys = p->tcfp_keys;
 	kfree(keys);
+	kfree(p->tcfp_keys_ex);
 }
 
 static bool offset_valid(struct sk_buff *skb, int offset)
@@ -119,38 +235,88 @@ 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)
+{
+	int ret = -EINVAL;
+
+	switch (htype) {
+	case TCA_PEDIT_KEY_EX_HDR_TYPE_ETH:
+		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)) {
+			*hoffset = skb_transport_offset(skb);
+			ret = 0;
+		}
+		break;
+	default:
+		ret = -EINVAL;
+		break;
+	};
+
+	return ret;
+}
+
 static int tcf_pedit(struct sk_buff *skb, const struct tc_action *a,
 		     struct tcf_result *res)
 {
 	struct tcf_pedit *p = to_pedit(a);
 	int i;
-	unsigned int off;
 
 	if (skb_unclone(skb, GFP_ATOMIC))
 		return p->tcf_action;
 
-	off = skb_network_offset(skb);
-
 	spin_lock(&p->tcf_lock);
 
 	tcf_lastuse_update(&p->tcf_tm);
 
 	if (p->tcfp_nkeys > 0) {
 		struct tc_pedit_key *tkey = p->tcfp_keys;
+		struct tcf_pedit_key_ex *tkey_ex = p->tcfp_keys_ex;
+		enum pedit_header_type htype = TCA_PEDIT_KEY_EX_HDR_TYPE_NETWORK;
+		enum pedit_cmd cmd = TCA_PEDIT_KEY_EX_CMD_SET;
 
 		for (i = p->tcfp_nkeys; i > 0; i--, tkey++) {
 			u32 *ptr, _data;
 			int offset = tkey->off;
+			int hoffset;
+			u32 val;
+			int rc;
+
+			if (tkey_ex) {
+				htype = tkey_ex->htype;
+				cmd = tkey_ex->cmd;
+
+				tkey_ex++;
+			}
+
+			rc = pedit_skb_hdr_offset(skb, htype, &hoffset);
+			if (rc) {
+				pr_info("tc filter pedit bad header type specified (0x%x)\n",
+					htype);
+				goto bad;
+			}
 
 			if (tkey->offmask) {
 				char *d, _d;
 
-				if (!offset_valid(skb, off + tkey->at)) {
+				if (!offset_valid(skb, hoffset + tkey->at)) {
 					pr_info("tc filter pedit 'at' offset %d out of bounds\n",
-						off + tkey->at);
+						hoffset + tkey->at);
 					goto bad;
 				}
-				d = skb_header_pointer(skb, off + tkey->at, 1,
+				d = skb_header_pointer(skb, hoffset + tkey->at, 1,
 						       &_d);
 				if (!d)
 					goto bad;
@@ -163,19 +329,32 @@ static int tcf_pedit(struct sk_buff *skb, const struct tc_action *a,
 				goto bad;
 			}
 
-			if (!offset_valid(skb, off + offset)) {
+			if (!offset_valid(skb, hoffset + offset)) {
 				pr_info("tc filter pedit offset %d out of bounds\n",
-					offset);
+					hoffset + offset);
 				goto bad;
 			}
 
-			ptr = skb_header_pointer(skb, off + offset, 4, &_data);
+			ptr = skb_header_pointer(skb, hoffset + offset, 4, &_data);
 			if (!ptr)
 				goto bad;
 			/* just do it, baby */
-			*ptr = ((*ptr & tkey->mask) ^ tkey->val);
+			switch (cmd) {
+			case TCA_PEDIT_KEY_EX_CMD_SET:
+				val = tkey->val;
+				break;
+			case TCA_PEDIT_KEY_EX_CMD_ADD:
+				val = (*ptr + tkey->val) & ~tkey->mask;
+				break;
+			default:
+				pr_info("tc filter pedit bad command (%d)\n",
+					cmd);
+				goto bad;
+			}
+
+			*ptr = ((*ptr & tkey->mask) ^ val);
 			if (ptr == &_data)
-				skb_store_bits(skb, off + offset, ptr, 4);
+				skb_store_bits(skb, hoffset + offset, ptr, 4);
 		}
 
 		goto done;
@@ -215,8 +394,15 @@ static int tcf_pedit_dump(struct sk_buff *skb, struct tc_action *a,
 	opt->refcnt = p->tcf_refcnt - ref;
 	opt->bindcnt = p->tcf_bindcnt - bind;
 
+	if (p->tcfp_keys_ex) {
+		tcf_pedit_key_ex_dump(skb, p->tcfp_keys_ex, p->tcfp_nkeys);
+
+		if (nla_put(skb, TCA_PEDIT_PARMS_EX, s, opt))
+			goto nla_put_failure;
+	} else {
 		if (nla_put(skb, TCA_PEDIT_PARMS, s, opt))
 			goto nla_put_failure;
+	}
 
 	tcf_tm_dump(&t, &p->tcf_tm);
 	if (nla_put_64bit(skb, TCA_PEDIT_TM, sizeof(t), &t, TCA_PEDIT_PAD))