linux-next/samples/bpf/sockex3_user.c
Rong Tao e5659e4e19 samples/bpf: Fix sockex3 error: Missing BPF prog type
since commit 450b167fb9be("libbpf: clean up SEC() handling"),
sec_def_matches() does not recognize "socket/xxx" as "socket", therefore,
the BPF program type is not recognized.

Instead of sockex3_user.c parsing section names to get the BPF program fd.
We use the program array map to assign a static index to each BPF program
(get inspired by selftests/bpf progs/test_prog_array_init.c).
Therefore, use SEC("socket") as section name instead of SEC("socket/xxx"),
so that the BPF program is parsed to SOCKET_FILTER type. The "missing BPF
prog type" problem is solved.

How to reproduce this error:
$ cd samples/bpf
$ sudo ./sockex3
libbpf: prog 'bpf_func_PARSE_IP': missing BPF prog type, check ELF section name 'socket/3'
libbpf: prog 'bpf_func_PARSE_IP': failed to load: -22
libbpf: failed to load object './sockex3_kern.o'
ERROR: loading BPF object file failed

Signed-off-by: Rong Tao <rongtao@cestc.cn>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/tencent_EBA3C18864069E42175946973C2ACBAF5408@qq.com
2022-11-07 17:13:35 -08:00

101 lines
2.2 KiB
C

// SPDX-License-Identifier: GPL-2.0
#include <stdio.h>
#include <assert.h>
#include <bpf/bpf.h>
#include <bpf/libbpf.h>
#include "sock_example.h"
#include <unistd.h>
#include <arpa/inet.h>
struct flow_key_record {
__be32 src;
__be32 dst;
union {
__be32 ports;
__be16 port16[2];
};
__u32 ip_proto;
};
struct pair {
__u64 packets;
__u64 bytes;
};
int main(int argc, char **argv)
{
int i, sock, fd, main_prog_fd, hash_map_fd;
struct bpf_program *prog;
struct bpf_object *obj;
char filename[256];
FILE *f;
snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
obj = bpf_object__open_file(filename, NULL);
if (libbpf_get_error(obj)) {
fprintf(stderr, "ERROR: opening BPF object file failed\n");
return 0;
}
/* load BPF program */
if (bpf_object__load(obj)) {
fprintf(stderr, "ERROR: loading BPF object file failed\n");
goto cleanup;
}
hash_map_fd = bpf_object__find_map_fd_by_name(obj, "hash_map");
if (hash_map_fd < 0) {
fprintf(stderr, "ERROR: finding a map in obj file failed\n");
goto cleanup;
}
/* find BPF main program */
main_prog_fd = 0;
bpf_object__for_each_program(prog, obj) {
fd = bpf_program__fd(prog);
if (!strcmp(bpf_program__name(prog), "main_prog"))
main_prog_fd = fd;
}
if (main_prog_fd == 0) {
fprintf(stderr, "ERROR: can't find main_prog\n");
goto cleanup;
}
sock = open_raw_sock("lo");
/* attach BPF program to socket */
assert(setsockopt(sock, SOL_SOCKET, SO_ATTACH_BPF, &main_prog_fd,
sizeof(__u32)) == 0);
if (argc > 1)
f = popen("ping -4 -c5 localhost", "r");
else
f = popen("netperf -l 4 localhost", "r");
(void) f;
for (i = 0; i < 5; i++) {
struct flow_key_record key = {}, next_key;
struct pair value;
sleep(1);
printf("IP src.port -> dst.port bytes packets\n");
while (bpf_map_get_next_key(hash_map_fd, &key, &next_key) == 0) {
bpf_map_lookup_elem(hash_map_fd, &next_key, &value);
printf("%s.%05d -> %s.%05d %12lld %12lld\n",
inet_ntoa((struct in_addr){htonl(next_key.src)}),
next_key.port16[0],
inet_ntoa((struct in_addr){htonl(next_key.dst)}),
next_key.port16[1],
value.bytes, value.packets);
key = next_key;
}
}
cleanup:
bpf_object__close(obj);
return 0;
}