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Commit 853a14ba authored by Amir Vadai's avatar Amir Vadai Committed by David S. Miller
Browse files

net/act_pedit: Introduce 'add' operation 



This command could be useful to inc/dec fields.

For example, to forward any TCP packet and decrease its TTL:
$ tc filter add dev enp0s9 protocol ip parent ffff: \
    flower ip_proto tcp \
    action pedit munge ip ttl add 0xff pipe \
    action mirred egress redirect dev veth0

In the example above, adding 0xff to this u8 field is actually
decreasing it by one, since the operation is masked.

Signed-off-by: default avatarAmir Vadai <amir@vadai.me>
Reviewed-by: default avatarOr Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 71d0ed70

include/net/tc_act/tc_pedit.h

+1 −0
Original line number Diff line number Diff line
@@ -5,6 +5,7 @@ 


struct tcf_pedit_key_ex {

	enum pedit_header_type htype;

	enum pedit_cmd cmd;

};



struct tcf_pedit {

include/uapi/linux/tc_act/tc_pedit.h

+8 −0
Original line number Diff line number Diff line
@@ -20,6 +20,7 @@ enum { 
                                                                                

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)
@@ -38,6 +39,13 @@ enum pedit_header_type { 
};

#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

+26 −4
Original line number Diff line number Diff line
@@ -36,6 +36,7 @@ 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 },

};



static struct tcf_pedit_key_ex *tcf_pedit_keys_ex_parse(struct nlattr *nla,
@@ -75,14 +76,17 @@ 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]) {

		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) {

		if (k->htype > TCA_PEDIT_HDR_TYPE_MAX ||

		    k->cmd > TCA_PEDIT_CMD_MAX) {

			err = -EINVAL;

			goto err_out;

		}
@@ -110,7 +114,8 @@ static int tcf_pedit_key_ex_dump(struct sk_buff *skb, 


		key_start = nla_nest_start(skb, TCA_PEDIT_KEY_EX);



		if (nla_put_u16(skb, TCA_PEDIT_KEY_EX_HTYPE, keys_ex->htype)) {

		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;

		}
@@ -280,15 +285,19 @@ static int tcf_pedit(struct sk_buff *skb, const struct tc_action *a, 
		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++;

			}
@@ -330,7 +339,20 @@ static int tcf_pedit(struct sk_buff *skb, const struct tc_action *a, 
			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, hoffset + offset, ptr, 4);

		}