diff options
| author | Florian Westphal <fw@strlen.de> | 2016-02-16 17:24:08 +0100 |
|---|---|---|
| committer | Pablo Neira Ayuso <pablo@netfilter.org> | 2016-02-29 13:55:59 +0100 |
| commit | b07edbe1cf3dae9ba81f24888e2f2a9dbe778918 (patch) | |
| tree | ed0bb89d4e43f6eea804b4d1cbad01050dae3b30 | |
| parent | f12d33f4d83c6837d176e1aef337914089c77957 (diff) | |
netfilter: meta: add PRANDOM support
Can be used to randomly match packets e.g. for statistic traffic sampling.
See commit 3ad0040573b0c00f8848
("bpf: split state from prandom_u32() and consolidate {c, e}BPF prngs")
for more info why this doesn't use prandom_u32 directly.
Unlike bpf nft_meta can be built as a module, so add an EXPORT_SYMBOL
for prandom_seed_full_state too.
Cc: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
| -rw-r--r-- | include/uapi/linux/netfilter/nf_tables.h | 2 | ||||
| -rw-r--r-- | lib/random32.c | 1 | ||||
| -rw-r--r-- | net/netfilter/nft_meta.c | 11 |
3 files changed, 14 insertions, 0 deletions
diff --git a/include/uapi/linux/netfilter/nf_tables.h b/include/uapi/linux/netfilter/nf_tables.h index be41ffc128b8..b19be0a098c0 100644 --- a/include/uapi/linux/netfilter/nf_tables.h +++ b/include/uapi/linux/netfilter/nf_tables.h @@ -681,6 +681,7 @@ enum nft_exthdr_attributes { * @NFT_META_IIFGROUP: packet input interface group * @NFT_META_OIFGROUP: packet output interface group * @NFT_META_CGROUP: socket control group (skb->sk->sk_classid) + * @NFT_META_PRANDOM: a 32bit pseudo-random number */ enum nft_meta_keys { NFT_META_LEN, @@ -707,6 +708,7 @@ enum nft_meta_keys { NFT_META_IIFGROUP, NFT_META_OIFGROUP, NFT_META_CGROUP, + NFT_META_PRANDOM, }; /** diff --git a/lib/random32.c b/lib/random32.c index 12111910ccd0..510d1ce7d4d2 100644 --- a/lib/random32.c +++ b/lib/random32.c @@ -255,6 +255,7 @@ void prandom_seed_full_state(struct rnd_state __percpu *pcpu_state) prandom_warmup(state); } } +EXPORT_SYMBOL(prandom_seed_full_state); /* * Generate better values after random number generator diff --git a/net/netfilter/nft_meta.c b/net/netfilter/nft_meta.c index fe885bf271c5..16c50b0dd426 100644 --- a/net/netfilter/nft_meta.c +++ b/net/netfilter/nft_meta.c @@ -28,6 +28,8 @@ #include <uapi/linux/netfilter_bridge.h> /* NF_BR_PRE_ROUTING */ +static DEFINE_PER_CPU(struct rnd_state, nft_prandom_state); + void nft_meta_get_eval(const struct nft_expr *expr, struct nft_regs *regs, const struct nft_pktinfo *pkt) @@ -181,6 +183,11 @@ void nft_meta_get_eval(const struct nft_expr *expr, *dest = sock_cgroup_classid(&sk->sk_cgrp_data); break; #endif + case NFT_META_PRANDOM: { + struct rnd_state *state = this_cpu_ptr(&nft_prandom_state); + *dest = prandom_u32_state(state); + break; + } default: WARN_ON(1); goto err; @@ -277,6 +284,10 @@ int nft_meta_get_init(const struct nft_ctx *ctx, case NFT_META_OIFNAME: len = IFNAMSIZ; break; + case NFT_META_PRANDOM: + prandom_init_once(&nft_prandom_state); + len = sizeof(u32); + break; default: return -EOPNOTSUPP; } |