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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: Amir Vadai <amir@vadai.me>
Reviewed-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Amir Vadai 2017-02-07 09:56:08 +02:00 committed by David S. Miller
parent 71d0ed7079
commit 853a14ba46
3 changed files with 35 additions and 4 deletions
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1
include/net/tc_act/tc_pedit.h
View File

@ -5,6 +5,7 @@
struct tcf_pedit_key_ex {
enum pedit_header_type htype;
enum pedit_cmd cmd;
};
struct tcf_pedit {

8
include/uapi/linux/tc_act/tc_pedit.h
View File

@ -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 */

30
net/sched/act_pedit.c
View File

@ -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);
}