Hi,
Thanks. I noticed the addition of the get/set operation while working
on the patch and was unsure about how to deal with setting the
connmark, but I decided to add it for completeness sake. Perhaps a
better idea would be to remove set from the module and only keep
save/restore? It would simplify the code as well.
-Kristian
On Mon, Jan 6, 2014 at 1:42 PM, Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx> wrote:
> Hi,
>
> On Mon, Jan 06, 2014 at 01:29:12PM +0100, Kristian Evensen wrote:
>> From: Kristian Evensen <kristian.evensen@xxxxxxxxx>
>>
>> This patch adds a connmark module to nftables, which enables setting, storing
>> and restoring the connection mark (ctmark) of a tracked connection. It works in
>> the same way as xt_CONNMARK.
>>
>> Signed-off-by: Kristian Evensen <kristian.evensen@xxxxxxxxx>
>> ---
>> include/uapi/linux/netfilter/nf_tables.h | 35 +++++++
>> net/netfilter/Kconfig | 10 ++
>> net/netfilter/Makefile | 1 +
>> net/netfilter/nft_connmark.c | 169 +++++++++++++++++++++++++++++++
>> 4 files changed, 215 insertions(+)
>> create mode 100644 net/netfilter/nft_connmark.c
>>
>> diff --git a/include/uapi/linux/netfilter/nf_tables.h b/include/uapi/linux/netfilter/nf_tables.h
>> index aa86a152..ccf9f9f 100644
>> --- a/include/uapi/linux/netfilter/nf_tables.h
>> +++ b/include/uapi/linux/netfilter/nf_tables.h
>> @@ -682,6 +682,41 @@ enum nft_queue_attributes {
>> #define NFT_QUEUE_FLAG_MASK 0x03
>>
>> /**
>> + * enum nft_connmark_types - nf_tables connmark expression types
>> + *
>> + * @NFT_CONNMARK_SAVE: save connmark
>> + * @NFT_CONNMARK_RESTORE: restore connmark
>> + * @NFT_CONNMARK_SET: set connmark (iptables set-xmark)
>> + */
>> +enum nft_connmark_types {
>> + NFT_CONNMARK_SAVE,
>> + NFT_CONNMARK_RESTORE,
>> + NFT_CONNMARK_SET
>> +};
>> +
>> +/**
>> + * enum nft_connmark_attributes - nf_tables connmark expression netlink
>> + * attributes
>> + *
>> + * @NFTA_CONNMARK_MODE: conntrack action (save, set or restore) (NLA_U8)
>> + * @NFTA_CONNMARK_CTMARK: conntrack ctmark (NLA_U32)
>> + * @NFTA_CONNMARK_CTMASK: conntrack ctmask (NLA_U32)
>> + * @NFTA_CONNMARK_NFMASK: conntrack nfmask (NLA_U32)
>> + */
>> +
>> +enum nft_connmark_attributes {
>> + NFTA_CONNMARK_UNSPEC,
>> + NFTA_CONNMARK_MODE,
>> + NFTA_CONNMARK_CTMARK,
>> + NFTA_CONNMARK_CTMASK,
>> + NFTA_CONNMARK_NFMASK,
>> + __NFTA_CONNMARK_MAX,
>> +};
>> +#define NFTA_CONNMARK_MAX (__NFTA_CONNMARK_MAX - 1)
>> +
>> +#define NFT_CONNMARK_DEFAULT_MASK 0xFFFFFFFF
>> +
>> +/**
>> * enum nft_reject_types - nf_tables reject expression reject types
>> *
>> * @NFT_REJECT_ICMP_UNREACH: reject using ICMP unreachable
>> diff --git a/net/netfilter/Kconfig b/net/netfilter/Kconfig
>> index 0609514..d3ff630 100644
>> --- a/net/netfilter/Kconfig
>> +++ b/net/netfilter/Kconfig
>> @@ -471,6 +471,16 @@ config NFT_COUNTER
>> This option adds the "counter" expression that you can use to
>> include packet and byte counters in a rule.
>>
>> +config NFT_CONNMARK
>> + depends on NF_TABLES
>> + depends on NF_CONNTRACK
>> + depends on NETFILTER_ADVANCED
>> + select NF_CONNTRACK_MARK
>> + tristate "Netfilter nf_tables conntrack module"
>> + help
>> + This option adds the "connmark" expression that can be used to
>> + set, save or restore a mark on a tracked connection.
>> +
>> config NFT_LOG
>> depends on NF_TABLES
>> tristate "Netfilter nf_tables log module"
>> diff --git a/net/netfilter/Makefile b/net/netfilter/Makefile
>> index 39e4a7b..5097a2f 100644
>> --- a/net/netfilter/Makefile
>> +++ b/net/netfilter/Makefile
>> @@ -71,6 +71,7 @@ nf_tables-objs += nft_bitwise.o nft_byteorder.o nft_payload.o
>>
>> obj-$(CONFIG_NF_TABLES) += nf_tables.o
>> obj-$(CONFIG_NFT_COMPAT) += nft_compat.o
>> +obj-$(CONFIG_NFT_CONNMARK) += nft_connmark.o
>> obj-$(CONFIG_NFT_EXTHDR) += nft_exthdr.o
>> obj-$(CONFIG_NFT_META) += nft_meta.o
>> obj-$(CONFIG_NFT_CT) += nft_ct.o
>> diff --git a/net/netfilter/nft_connmark.c b/net/netfilter/nft_connmark.c
>> new file mode 100644
>> index 0000000..04d56d1
>> --- /dev/null
>> +++ b/net/netfilter/nft_connmark.c
>> @@ -0,0 +1,169 @@
>> +/* Copyright (c) 2013 Kristian Evensen <kristian.evensen@xxxxxxxxx>
>> + *
>> + * This program is free software; you can redistribute it and/or modify
>> + * it under the terms of the GNU General Public License version 2 as
>> + * published by the Free Software Foundation.
>> + */
>> +
>> +#include <linux/kernel.h>
>> +#include <linux/init.h>
>> +#include <linux/module.h>
>> +#include <linux/netlink.h>
>> +#include <linux/netfilter.h>
>> +#include <linux/netfilter/nf_tables.h>
>> +#include <net/netfilter/nf_tables.h>
>> +#include <net/netfilter/nf_conntrack.h>
>> +#include <net/netfilter/nf_conntrack_ecache.h>
>> +
>> +struct nft_connmark {
>> + u32 ctmask;
>> + union{
>> + u32 ctmark;
>> + u32 nfmask;
>> + };
>> + u8 mode;
>> +};
>> +
>> +static void nft_connmark_eval(const struct nft_expr *expr,
>> + struct nft_data data[NFT_REG_MAX + 1],
>> + const struct nft_pktinfo *pkt)
>> +{
>> + struct nft_connmark *priv = nft_expr_priv(expr);
>> + enum ip_conntrack_info ctinfo;
>> + struct nf_conn *ct;
>> + u_int32_t newmark;
>> +
>> + ct = nf_ct_get(pkt->skb, &ctinfo);
>> + if (ct == NULL)
>> + return;
>> +
>> + switch (priv->mode) {
>> + case NFT_CONNMARK_SET:
>> + newmark = (ct->mark & ~priv->ctmask) ^ priv->ctmark;
>> + if (ct->mark != newmark) {
>> + ct->mark = newmark;
>> + nf_conntrack_event_cache(IPCT_MARK, ct);
>> + }
>> + break;
>> + case NFT_CONNMARK_SAVE:
>> + newmark = (ct->mark & ~priv->ctmask) ^
>> + (pkt->skb->mark & priv->nfmask);
>> +
>> + if (ct->mark != newmark) {
>> + ct->mark = newmark;
>> + nf_conntrack_event_cache(IPCT_MARK, ct);
>> + }
>> + break;
>> + case NFT_CONNMARK_RESTORE:
>> + newmark = (pkt->skb->mark & ~priv->nfmask) ^
>> + (ct->mark & priv->ctmask);
>> + pkt->skb->mark = newmark;
>
> We already have expressions for bitmask operations and to fetch the
> packet mark into a register. These operations can be implemented in
> the existing meta expressions as NFT_META_CONNMARK.
>
> Note that we now have two meta flavours:
>
> http://git.kernel.org/cgit/linux/kernel/git/pablo/nftables.git/commit/net/netfilter/nft_meta.c?id=e035b77ac7be430a5fef8c9c23f60b6b50ec81c5
>
> So the idea is to make a patch that allows us to retrieve and to set
> the connmark value.
>
> Thanks.
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