This allows to redirect bridged packets to local machine:
ether type ip ether daddr set aa:53:08:12:34:56 meta pkttype set unicast
Without 'set unicast', ip stack discards PACKET_OTHERHOST skbs.
It is also useful to add support for a '-m cluster like' nft rule
(where switch floods packets to several nodes, and each cluster node
node processes a subset of packets for load distribution).
Mangling is restricted to HOST/OTHER/BROAD/MULTICAST, i.e. you cannot set
skb->pkt_type to PACKET_KERNEL or change PACKET_LOOPBACK to PACKET_HOST.
Signed-off-by: Florian Westphal <fw@xxxxxxxxx>
---
Changes since v1:
- allow setting pkttype to any of host/broadcast/multicast/other.
net/netfilter/nft_meta.c | 38 ++++++++++++++++++++++++++++++++++++++
1 file changed, 38 insertions(+)
diff --git a/net/netfilter/nft_meta.c b/net/netfilter/nft_meta.c
index 85a465b..c89f835 100644
--- a/net/netfilter/nft_meta.c
+++ b/net/netfilter/nft_meta.c
@@ -26,6 +26,8 @@
#include <net/netfilter/nf_tables_core.h>
#include <net/netfilter/nft_meta.h>
+#include <uapi/linux/netfilter_bridge.h> /* NF_BR_PRE_ROUTING */
+
void nft_meta_get_eval(const struct nft_expr *expr,
struct nft_regs *regs,
const struct nft_pktinfo *pkt)
@@ -190,6 +192,13 @@ err:
}
EXPORT_SYMBOL_GPL(nft_meta_get_eval);
+/* don't change or set _LOOPBACK, _USER, etc. */
+static bool pkt_type_ok(u32 p)
+{
+ return p == PACKET_HOST || p == PACKET_BROADCAST ||
+ p == PACKET_MULTICAST || p == PACKET_OTHERHOST;
+}
+
void nft_meta_set_eval(const struct nft_expr *expr,
struct nft_regs *regs,
const struct nft_pktinfo *pkt)
@@ -205,6 +214,11 @@ void nft_meta_set_eval(const struct nft_expr *expr,
case NFT_META_PRIORITY:
skb->priority = value;
break;
+ case NFT_META_PKTTYPE:
+ if (skb->pkt_type != value &&
+ pkt_type_ok(value) && pkt_type_ok(skb->pkt_type))
+ skb->pkt_type = value;
+ break;
case NFT_META_NFTRACE:
skb->nf_trace = 1;
break;
@@ -273,6 +287,24 @@ int nft_meta_get_init(const struct nft_ctx *ctx,
}
EXPORT_SYMBOL_GPL(nft_meta_get_init);
+static int nft_meta_set_init_pkttype(const struct nft_ctx *ctx)
+{
+ unsigned int hooks;
+
+ switch (ctx->afi->family) {
+ case NFPROTO_BRIDGE:
+ hooks = 1 << NF_BR_PRE_ROUTING;
+ break;
+ case NFPROTO_NETDEV:
+ hooks = 1 << NF_NETDEV_INGRESS;
+ break;
+ default:
+ return -EOPNOTSUPP;
+ }
+
+ return nft_chain_validate_hooks(ctx->chain, hooks);
+}
+
int nft_meta_set_init(const struct nft_ctx *ctx,
const struct nft_expr *expr,
const struct nlattr * const tb[])
@@ -290,6 +322,12 @@ int nft_meta_set_init(const struct nft_ctx *ctx,
case NFT_META_NFTRACE:
len = sizeof(u8);
break;
+ case NFT_META_PKTTYPE:
+ err = nft_meta_set_init_pkttype(ctx);
+ if (err)
+ return err;
+ len = sizeof(u8);
+ break;
default:
return -EOPNOTSUPP;
}
--
2.4.10
--
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