bpf: move various OFFSET helpers into bpf_net_helpers.h
Test: TreeHugger
Signed-off-by: Maciej Żenczykowski <maze@google.com>
Change-Id: Idb7b5ff1c5caa403e10d257b201dfa7c2cbf5a20
diff --git a/bpf_progs/bpf_net_helpers.h b/bpf_progs/bpf_net_helpers.h
index 11d4bbf..a86c3e6 100644
--- a/bpf_progs/bpf_net_helpers.h
+++ b/bpf_progs/bpf_net_helpers.h
@@ -48,13 +48,41 @@
__be32 identification;
};
+// ----- Helper functions for offsets to fields -----
+
+// They all assume simple IP packets:
+// - no VLAN ethernet tags
+// - no IPv4 options (see IPV4_HLEN/TCP4_OFFSET/UDP4_OFFSET)
+// - no IPv6 extension headers
+// - no TCP options (see TCP_HLEN)
+
+//#define ETH_HLEN sizeof(struct ethhdr)
+#define IP4_HLEN sizeof(struct iphdr)
+#define IP6_HLEN sizeof(struct ipv6hdr)
+#define TCP_HLEN sizeof(struct tcphdr)
+#define UDP_HLEN sizeof(struct udphdr)
+
// Offsets from beginning of L4 (TCP/UDP) header
#define TCP_OFFSET(field) offsetof(struct tcphdr, field)
#define UDP_OFFSET(field) offsetof(struct udphdr, field)
-// Offsets from beginning of L3 (IPv4/IPv6) header
+// Offsets from beginning of L3 (IPv4) header
#define IP4_OFFSET(field) offsetof(struct iphdr, field)
+#define IP4_TCP_OFFSET(field) (IP4_HLEN + TCP_OFFSET(field))
+#define IP4_UDP_OFFSET(field) (IP4_HLEN + UDP_OFFSET(field))
+
+// Offsets from beginning of L3 (IPv6) header
#define IP6_OFFSET(field) offsetof(struct ipv6hdr, field)
+#define IP6_TCP_OFFSET(field) (IP6_HLEN + TCP_OFFSET(field))
+#define IP6_UDP_OFFSET(field) (IP6_HLEN + UDP_OFFSET(field))
+
+// Offsets from beginning of L2 (ie. Ethernet) header (which must be present)
+#define ETH_IP4_OFFSET(field) (ETH_HLEN + IP4_OFFSET(field))
+#define ETH_IP4_TCP_OFFSET(field) (ETH_HLEN + IP4_TCP_OFFSET(field))
+#define ETH_IP4_UDP_OFFSET(field) (ETH_HLEN + IP4_UDP_OFFSET(field))
+#define ETH_IP6_OFFSET(field) (ETH_HLEN + IP6_OFFSET(field))
+#define ETH_IP6_TCP_OFFSET(field) (ETH_HLEN + IP6_TCP_OFFSET(field))
+#define ETH_IP6_UDP_OFFSET(field) (ETH_HLEN + IP6_UDP_OFFSET(field))
// this returns 0 iff skb->sk is NULL
static uint64_t (*bpf_get_socket_cookie)(struct __sk_buff* skb) = (void*)BPF_FUNC_get_socket_cookie;