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c7272ca720
mirror_iproute2/include/bpf_api.h
Daniel Borkmann c7272ca720 bpf: add initial support for attaching xdp progs 
Now that we made the BPF loader generic as a library, reuse it
for loading XDP programs as well. This basically adds a minimal
start of a facility for iproute2 to load XDP programs. There
currently only exists the xdp1_user.c sample code in the kernel
tree that sets up netlink directly and an iovisor/bcc front-end.

Since we have all the necessary infrastructure in place already
from tc side, we can just reuse its loader back-end and thus
facilitate migration and usability among the two for people
familiar with tc/bpf already. Sharing maps, performing tail calls,
etc works the same way as with tc. Naturally, once kernel
configuration API evolves, we will extend new features for XDP
here as well, resp. extend dumping of related netlink attributes.

Minimal example:

  clang -target bpf -O2 -Wall -c prog.c -o prog.o
  ip [-force] link set dev em1 xdp obj prog.o       # attaching
  ip [-d] link                                      # dumping
  ip link set dev em1 xdp off                       # detaching

For the dump, intention is that in the first line for each ip
link entry, we'll see "xdp" to indicate that this device has an
XDP program attached. Once we dump some more useful information
via netlink (digest, etc), idea is that 'ip -d link' will then
display additional relevant program information below the "link/
ether [...]" output line for such devices, for example.

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
2016-12-09 12:44:12 -08:00

257 lines
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#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"
/** 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_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__ */
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