From 8afd54c87ad7089734ef0527937a256586ba828a Mon Sep 17 00:00:00 2001 From: Daniel Borkmann Date: Fri, 4 Mar 2016 15:15:03 +0100 Subject: [PATCH] bpf: add flags to bpf_skb_store_bytes for clearing hash When overwriting parts of the packet with bpf_skb_store_bytes() that were fed previously into skb->hash calculation, we should clear the current hash with skb_clear_hash(), so that a next skb_get_hash() call can determine the correct hash related to this skb. Signed-off-by: Daniel Borkmann Acked-by: Alexei Starovoitov Signed-off-by: David S. Miller --- include/uapi/linux/bpf.h | 1 + net/core/filter.c | 4 +++- 2 files changed, 4 insertions(+), 1 deletion(-) diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index ee219328..2e3e903 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -305,6 +305,7 @@ enum bpf_func_id { /* BPF_FUNC_skb_store_bytes flags. */ #define BPF_F_RECOMPUTE_CSUM (1ULL << 0) +#define BPF_F_INVALIDATE_HASH (1ULL << 1) /* BPF_FUNC_l3_csum_replace and BPF_FUNC_l4_csum_replace flags. * First 4 bits are for passing the header field size. diff --git a/net/core/filter.c b/net/core/filter.c index 356a251..a1fe246 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -1353,7 +1353,7 @@ static u64 bpf_skb_store_bytes(u64 r1, u64 r2, u64 r3, u64 r4, u64 flags) unsigned int len = (unsigned int) r4; void *ptr; - if (unlikely(flags & ~(BPF_F_RECOMPUTE_CSUM))) + if (unlikely(flags & ~(BPF_F_RECOMPUTE_CSUM | BPF_F_INVALIDATE_HASH))) return -EINVAL; /* bpf verifier guarantees that: @@ -1384,6 +1384,8 @@ static u64 bpf_skb_store_bytes(u64 r1, u64 r2, u64 r3, u64 r4, u64 flags) if (flags & BPF_F_RECOMPUTE_CSUM) skb_postpush_rcsum(skb, ptr, len); + if (flags & BPF_F_INVALIDATE_HASH) + skb_clear_hash(skb); return 0; } -- 2.7.4