From 91bc4822c3d61b9bb7ef66d3b77948a4f9177954 Mon Sep 17 00:00:00 2001 From: Alexei Starovoitov Date: Wed, 1 Apr 2015 17:12:13 -0700 Subject: tc: bpf: add checksum helpers Commit 608cd71a9c7c ("tc: bpf: generalize pedit action") has added the possibility to mangle packet data to BPF programs in the tc pipeline. This patch adds two helpers bpf_l3_csum_replace() and bpf_l4_csum_replace() for fixing up the protocol checksums after the packet mangling. It also adds 'flags' argument to bpf_skb_store_bytes() helper to avoid unnecessary checksum recomputations when BPF programs adjusting l3/l4 checksums and documents all three helpers in uapi header. Moreover, a sample program is added to show how BPF programs can make use of the mangle and csum helpers. Signed-off-by: Alexei Starovoitov Acked-by: Daniel Borkmann Signed-off-by: David S. Miller --- samples/bpf/bpf_helpers.h | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'samples/bpf/bpf_helpers.h') diff --git a/samples/bpf/bpf_helpers.h b/samples/bpf/bpf_helpers.h index ca0333146006..72540ec1f003 100644 --- a/samples/bpf/bpf_helpers.h +++ b/samples/bpf/bpf_helpers.h @@ -37,4 +37,11 @@ struct bpf_map_def { unsigned int max_entries; }; +static int (*bpf_skb_store_bytes)(void *ctx, int off, void *from, int len, int flags) = + (void *) BPF_FUNC_skb_store_bytes; +static int (*bpf_l3_csum_replace)(void *ctx, int off, int from, int to, int flags) = + (void *) BPF_FUNC_l3_csum_replace; +static int (*bpf_l4_csum_replace)(void *ctx, int off, int from, int to, int flags) = + (void *) BPF_FUNC_l4_csum_replace; + #endif -- cgit v1.2.3