From 853a14ba4682f820266469979c9297debc05f60c Mon Sep 17 00:00:00 2001 From: Amir Vadai Date: Tue, 7 Feb 2017 09:56:08 +0200 Subject: [PATCH] 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 Reviewed-by: Or Gerlitz Signed-off-by: David S. Miller --- include/net/tc_act/tc_pedit.h | 1 + include/uapi/linux/tc_act/tc_pedit.h | 8 ++++++++ net/sched/act_pedit.c | 30 ++++++++++++++++++++++++++---- 3 files changed, 35 insertions(+), 4 deletions(-) diff --git a/include/net/tc_act/tc_pedit.h b/include/net/tc_act/tc_pedit.h index e076f22..dfbd6ee 100644 --- a/include/net/tc_act/tc_pedit.h +++ b/include/net/tc_act/tc_pedit.h @@ -5,6 +5,7 @@ struct tcf_pedit_key_ex { enum pedit_header_type htype; + enum pedit_cmd cmd; }; struct tcf_pedit { diff --git a/include/uapi/linux/tc_act/tc_pedit.h b/include/uapi/linux/tc_act/tc_pedit.h index 22f19ee..143d2b3 100644 --- a/include/uapi/linux/tc_act/tc_pedit.h +++ b/include/uapi/linux/tc_act/tc_pedit.h @@ -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 */ diff --git a/net/sched/act_pedit.c b/net/sched/act_pedit.c index fdd012b..c131047 100644 --- a/net/sched/act_pedit.c +++ b/net/sched/act_pedit.c @@ -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); } -- 2.7.4