From b4aae759c22e71a3c32144f0b3bc4f2fa4aaae98 Mon Sep 17 00:00:00 2001 From: Florian Westphal Date: Thu, 10 Dec 2015 18:04:07 +0100 Subject: [PATCH] netfilter: meta: add support for setting skb->pkttype 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 Signed-off-by: Pablo Neira Ayuso --- 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 5bcd1b0..fe885bf 100644 --- a/net/netfilter/nft_meta.c +++ b/net/netfilter/nft_meta.c @@ -26,6 +26,8 @@ #include #include +#include /* 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; } -- 2.7.4