1 files changed, 275 insertions, 0 deletions
diff --git a/include/bpf_api.h b/include/bpf_api.h
new file mode 100644
index 0000000..82c4708
--- /dev/null
+++ b/include/bpf_api.h
@@ -0,0 +1,275 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __BPF_API__
+#define __BPF_API__
+
+/* Note:
+ *
+ * This file can be included into eBPF kernel programs. It contains
+ * a couple of useful helper functions, map/section ABI (bpf_elf.h),
+ * misc macros and some eBPF specific LLVM built-ins.
+ */
+
+#include <stdint.h>
+
+#include <linux/pkt_cls.h>
+#include <linux/bpf.h>
+#include <linux/filter.h>
+
+#include <asm/byteorder.h>
+
+#include "bpf_elf.h"
+
+/** libbpf pin type. */
+enum libbpf_pin_type {
+	LIBBPF_PIN_NONE,
+	/* PIN_BY_NAME: pin maps by name (in /sys/fs/bpf by default) */
+	LIBBPF_PIN_BY_NAME,
+};
+
+/** Type helper macros. */
+
+#define __uint(name, val) int (*name)[val]
+#define __type(name, val) typeof(val) *name
+#define __array(name, val) typeof(val) *name[]
+
+/** Misc macros. */
+
+#ifndef __stringify
+# define __stringify(X)		#X
+#endif
+
+#ifndef __maybe_unused
+# define __maybe_unused		__attribute__((__unused__))
+#endif
+
+#ifndef offsetof
+# define offsetof(TYPE, MEMBER)	__builtin_offsetof(TYPE, MEMBER)
+#endif
+
+#ifndef likely
+# define likely(X)		__builtin_expect(!!(X), 1)
+#endif
+
+#ifndef unlikely
+# define unlikely(X)		__builtin_expect(!!(X), 0)
+#endif
+
+#ifndef htons
+# define htons(X)		__constant_htons((X))
+#endif
+
+#ifndef ntohs
+# define ntohs(X)		__constant_ntohs((X))
+#endif
+
+#ifndef htonl
+# define htonl(X)		__constant_htonl((X))
+#endif
+
+#ifndef ntohl
+# define ntohl(X)		__constant_ntohl((X))
+#endif
+
+#ifndef __inline__
+# define __inline__		__attribute__((always_inline))
+#endif
+
+/** Section helper macros. */
+
+#ifndef __section
+# define __section(NAME)						\
+	__attribute__((section(NAME), used))
+#endif
+
+#ifndef __section_tail
+# define __section_tail(ID, KEY)					\
+	__section(__stringify(ID) "/" __stringify(KEY))
+#endif
+
+#ifndef __section_xdp_entry
+# define __section_xdp_entry						\
+	__section(ELF_SECTION_PROG)
+#endif
+
+#ifndef __section_cls_entry
+# define __section_cls_entry						\
+	__section(ELF_SECTION_CLASSIFIER)
+#endif
+
+#ifndef __section_act_entry
+# define __section_act_entry						\
+	__section(ELF_SECTION_ACTION)
+#endif
+
+#ifndef __section_lwt_entry
+# define __section_lwt_entry						\
+	__section(ELF_SECTION_PROG)
+#endif
+
+#ifndef __section_license
+# define __section_license						\
+	__section(ELF_SECTION_LICENSE)
+#endif
+
+#ifndef __section_maps
+# define __section_maps							\
+	__section(ELF_SECTION_MAPS)
+#endif
+
+/** Declaration helper macros. */
+
+#ifndef BPF_LICENSE
+# define BPF_LICENSE(NAME)						\
+	char ____license[] __section_license = NAME
+#endif
+
+/** Classifier helper */
+
+#ifndef BPF_H_DEFAULT
+# define BPF_H_DEFAULT	-1
+#endif
+
+/** BPF helper functions for tc. Individual flags are in linux/bpf.h */
+
+#ifndef __BPF_FUNC
+# define __BPF_FUNC(NAME, ...)						\
+	(* NAME)(__VA_ARGS__) __maybe_unused
+#endif
+
+#ifndef BPF_FUNC
+# define BPF_FUNC(NAME, ...)						\
+	__BPF_FUNC(NAME, __VA_ARGS__) = (void *) BPF_FUNC_##NAME
+#endif
+
+/* Map access/manipulation */
+static void *BPF_FUNC(map_lookup_elem, void *map, const void *key);
+static int BPF_FUNC(map_update_elem, void *map, const void *key,
+		    const void *value, uint32_t flags);
+static int BPF_FUNC(map_delete_elem, void *map, const void *key);
+
+/* Time access */
+static uint64_t BPF_FUNC(ktime_get_ns);
+
+/* Debugging */
+
+/* FIXME: __attribute__ ((format(printf, 1, 3))) not possible unless
+ * llvm bug https://llvm.org/bugs/show_bug.cgi?id=26243 gets resolved.
+ * It would require ____fmt to be made const, which generates a reloc
+ * entry (non-map).
+ */
+static void BPF_FUNC(trace_printk, const char *fmt, int fmt_size, ...);
+
+#ifndef printt
+# define printt(fmt, ...)						\
+	({								\
+		char ____fmt[] = fmt;					\
+		trace_printk(____fmt, sizeof(____fmt), ##__VA_ARGS__);	\
+	})
+#endif
+
+/* Random numbers */
+static uint32_t BPF_FUNC(get_prandom_u32);
+
+/* Tail calls */
+static void BPF_FUNC(tail_call, struct __sk_buff *skb, void *map,
+		     uint32_t index);
+
+/* System helpers */
+static uint32_t BPF_FUNC(get_smp_processor_id);
+static uint32_t BPF_FUNC(get_numa_node_id);
+
+/* Packet misc meta data */
+static uint32_t BPF_FUNC(get_cgroup_classid, struct __sk_buff *skb);
+static int BPF_FUNC(skb_under_cgroup, void *map, uint32_t index);
+
+static uint32_t BPF_FUNC(get_route_realm, struct __sk_buff *skb);
+static uint32_t BPF_FUNC(get_hash_recalc, struct __sk_buff *skb);
+static uint32_t BPF_FUNC(set_hash_invalid, struct __sk_buff *skb);
+
+/* Packet redirection */
+static int BPF_FUNC(redirect, int ifindex, uint32_t flags);
+static int BPF_FUNC(clone_redirect, struct __sk_buff *skb, int ifindex,
+		    uint32_t flags);
+
+/* Packet manipulation */
+static int BPF_FUNC(skb_load_bytes, struct __sk_buff *skb, uint32_t off,
+		    void *to, uint32_t len);
+static int BPF_FUNC(skb_store_bytes, struct __sk_buff *skb, uint32_t off,
+		    const void *from, uint32_t len, uint32_t flags);
+
+static int BPF_FUNC(l3_csum_replace, struct __sk_buff *skb, uint32_t off,
+		    uint32_t from, uint32_t to, uint32_t flags);
+static int BPF_FUNC(l4_csum_replace, struct __sk_buff *skb, uint32_t off,
+		    uint32_t from, uint32_t to, uint32_t flags);
+static int BPF_FUNC(csum_diff, const void *from, uint32_t from_size,
+		    const void *to, uint32_t to_size, uint32_t seed);
+static int BPF_FUNC(csum_update, struct __sk_buff *skb, uint32_t wsum);
+
+static int BPF_FUNC(skb_change_type, struct __sk_buff *skb, uint32_t type);
+static int BPF_FUNC(skb_change_proto, struct __sk_buff *skb, uint32_t proto,
+		    uint32_t flags);
+static int BPF_FUNC(skb_change_tail, struct __sk_buff *skb, uint32_t nlen,
+		    uint32_t flags);
+
+static int BPF_FUNC(skb_pull_data, struct __sk_buff *skb, uint32_t len);
+
+/* Event notification */
+static int __BPF_FUNC(skb_event_output, struct __sk_buff *skb, void *map,
+		      uint64_t index, const void *data, uint32_t size) =
+		      (void *) BPF_FUNC_perf_event_output;
+
+/* Packet vlan encap/decap */
+static int BPF_FUNC(skb_vlan_push, struct __sk_buff *skb, uint16_t proto,
+		    uint16_t vlan_tci);
+static int BPF_FUNC(skb_vlan_pop, struct __sk_buff *skb);
+
+/* Packet tunnel encap/decap */
+static int BPF_FUNC(skb_get_tunnel_key, struct __sk_buff *skb,
+		    struct bpf_tunnel_key *to, uint32_t size, uint32_t flags);
+static int BPF_FUNC(skb_set_tunnel_key, struct __sk_buff *skb,
+		    const struct bpf_tunnel_key *from, uint32_t size,
+		    uint32_t flags);
+
+static int BPF_FUNC(skb_get_tunnel_opt, struct __sk_buff *skb,
+		    void *to, uint32_t size);
+static int BPF_FUNC(skb_set_tunnel_opt, struct __sk_buff *skb,
+		    const void *from, uint32_t size);
+
+/** LLVM built-ins, mem*() routines work for constant size */
+
+#ifndef lock_xadd
+# define lock_xadd(ptr, val)	((void) __sync_fetch_and_add(ptr, val))
+#endif
+
+#ifndef memset
+# define memset(s, c, n)	__builtin_memset((s), (c), (n))
+#endif
+
+#ifndef memcpy
+# define memcpy(d, s, n)	__builtin_memcpy((d), (s), (n))
+#endif
+
+#ifndef memmove
+# define memmove(d, s, n)	__builtin_memmove((d), (s), (n))
+#endif
+
+/* FIXME: __builtin_memcmp() is not yet fully useable unless llvm bug
+ * https://llvm.org/bugs/show_bug.cgi?id=26218 gets resolved. Also
+ * this one would generate a reloc entry (non-map), otherwise.
+ */
+#if 0
+#ifndef memcmp
+# define memcmp(a, b, n)	__builtin_memcmp((a), (b), (n))
+#endif
+#endif
+
+unsigned long long load_byte(void *skb, unsigned long long off)
+	asm ("llvm.bpf.load.byte");
+
+unsigned long long load_half(void *skb, unsigned long long off)
+	asm ("llvm.bpf.load.half");
+
+unsigned long long load_word(void *skb, unsigned long long off)
+	asm ("llvm.bpf.load.word");
+
+#endif /* __BPF_API__ */