BpfClassic - add three more macros
Example use case:
BPF_LOAD_SKB_PROTOCOL,
BPF2_ACCEPT_IF_EQUAL(ETH_P_ARP),
BPF2_REJECT_IF_NOT_EQUAL(ETH_P_IP),
BPF_LOAD_IPV4_BE16(frag_off),
BPF2_REJECT_IF_ANY_BITS_SET(IP_MF | IP_OFFMASK),
BPF_ACCEPT,
which is a sample program which accepts ARP plus non-fragmented IPv4.
Test: TreeHugger
Signed-off-by: Maciej Żenczykowski <maze@google.com>
Change-Id: Ibe6f9f7941f11bc7b767a092d3d108fa0291f360
diff --git a/staticlibs/native/bpf_headers/include/bpf/BpfClassic.h b/staticlibs/native/bpf_headers/include/bpf/BpfClassic.h
index 9b38dee..dd0804c 100644
--- a/staticlibs/native/bpf_headers/include/bpf/BpfClassic.h
+++ b/staticlibs/native/bpf_headers/include/bpf/BpfClassic.h
@@ -22,11 +22,25 @@
// Reject the packet
#define BPF_REJECT BPF_STMT(BPF_RET | BPF_K, 0)
+// *TWO* instructions: compare and if not equal jump over the accept statement
+#define BPF2_ACCEPT_IF_EQUAL(v) \
+ BPF_JUMP(BPF_JMP | BPF_JEQ | BPF_K, (v), 0, 1), \
+ BPF_ACCEPT
+
// *TWO* instructions: compare and if equal jump over the reject statement
#define BPF2_REJECT_IF_NOT_EQUAL(v) \
BPF_JUMP(BPF_JMP | BPF_JEQ | BPF_K, (v), 1, 0), \
BPF_REJECT
+// *TWO* instructions: compare and if none of the bits are set jump over the reject statement
+#define BPF2_REJECT_IF_ANY_BITS_SET(v) \
+ BPF_JUMP(BPF_JMP | BPF_JSET | BPF_K, (v), 0, 1), \
+ BPF_REJECT
+
+// loads skb->protocol
+#define BPF_LOAD_SKB_PROTOCOL \
+ BPF_STMT(BPF_LD | BPF_H | BPF_ABS, (__u32)SKF_AD_OFF + SKF_AD_PROTOCOL)
+
// 8-bit load relative to start of link layer (mac/ethernet) header.
#define BPF_LOAD_MAC_RELATIVE_U8(ofs) \
BPF_STMT(BPF_LD | BPF_B | BPF_ABS, (__u32)SKF_LL_OFF + (ofs))