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[bpf-next,11/13] selftests/bpf: convert bpf tunnel test to BPF_ADJ_ROOM_MAC

Message ID 20190320144944.147862-12-willemdebruijn.kernel@gmail.com
State Changes Requested
Delegated to: BPF Maintainers
Headers show
Series bpf tc tunneling | expand

Commit Message

Willem de Bruijn March 20, 2019, 2:49 p.m. UTC 
From: Willem de Bruijn <willemb@google.com>

Avoid moving the network layer header when prefixing tunnel headers.

This avoids an explicit call to bpf_skb_store_bytes and an implicit
move of the network header bytes in bpf_skb_adjust_room.

Signed-off-by: Willem de Bruijn <willemb@google.com>
---
 .../selftests/bpf/progs/test_tc_tunnel.c      | 25 +++----------------
 1 file changed, 3 insertions(+), 22 deletions(-)
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Patch

diff --git a/tools/testing/selftests/bpf/progs/test_tc_tunnel.c b/tools/testing/selftests/bpf/progs/test_tc_tunnel.c
index 900c5653105fe..f6a16fd23dbd5 100644
--- a/tools/testing/selftests/bpf/progs/test_tc_tunnel.c
+++ b/tools/testing/selftests/bpf/progs/test_tc_tunnel.c
@@ -72,7 +72,7 @@  static __always_inline int encap_ipv4(struct __sk_buff *skb, bool with_gre)
 	olen = with_gre ? sizeof(h_outer) : sizeof(h_outer.ip);
 
 	/* add room between mac and network header */
-	if (bpf_skb_adjust_room(skb, olen, BPF_ADJ_ROOM_NET, 0))
+	if (bpf_skb_adjust_room(skb, olen, BPF_ADJ_ROOM_MAC, 0))
 		return TC_ACT_SHOT;
 
 	/* prepare new outer network header */
@@ -94,12 +94,6 @@  static __always_inline int encap_ipv4(struct __sk_buff *skb, bool with_gre)
 				BPF_F_INVALIDATE_HASH) < 0)
 		return TC_ACT_SHOT;
 
-	/* bpf_skb_adjust_room has moved header to start of room: restore */
-	if (bpf_skb_store_bytes(skb, ETH_HLEN + olen,
-				&iph_inner, sizeof(iph_inner),
-				BPF_F_INVALIDATE_HASH) < 0)
-		return TC_ACT_SHOT;
-
 	return TC_ACT_OK;
 }
 
@@ -125,7 +119,7 @@  static __always_inline int encap_ipv6(struct __sk_buff *skb, bool with_gre)
 	olen = with_gre ? sizeof(h_outer) : sizeof(h_outer.ip);
 
 	/* add room between mac and network header */
-	if (bpf_skb_adjust_room(skb, olen, BPF_ADJ_ROOM_NET, 0))
+	if (bpf_skb_adjust_room(skb, olen, BPF_ADJ_ROOM_MAC, 0))
 		return TC_ACT_SHOT;
 
 	/* prepare new outer network header */
@@ -145,12 +139,6 @@  static __always_inline int encap_ipv6(struct __sk_buff *skb, bool with_gre)
 				BPF_F_INVALIDATE_HASH) < 0)
 		return TC_ACT_SHOT;
 
-	/* bpf_skb_adjust_room has moved header to start of room: restore */
-	if (bpf_skb_store_bytes(skb, ETH_HLEN + olen,
-				&iph_inner, sizeof(iph_inner),
-				BPF_F_INVALIDATE_HASH) < 0)
-		return TC_ACT_SHOT;
-
 	return TC_ACT_OK;
 }
 
@@ -207,14 +195,7 @@  static int decap_internal(struct __sk_buff *skb, int off, int len, char proto)
 		return TC_ACT_OK;
 	}
 
-	if (bpf_skb_load_bytes(skb, off + olen, &buf, olen) < 0)
-		return TC_ACT_OK;
-
-	if (bpf_skb_adjust_room(skb, -olen, BPF_ADJ_ROOM_NET, 0))
-		return TC_ACT_SHOT;
-
-	/* bpf_skb_adjust_room has moved outer over inner header: restore */
-	if (bpf_skb_store_bytes(skb, off, buf, len, BPF_F_INVALIDATE_HASH) < 0)
+	if (bpf_skb_adjust_room(skb, -olen, BPF_ADJ_ROOM_MAC, 0))
 		return TC_ACT_SHOT;
 
 	return TC_ACT_OK;