Currently, executing test_cgrp2_sock2 fails due to wrong section
header. This 'cgroup/sock1' style section is previously used at
'samples/bpf_load' (deprecated) BPF loader. Because this style isn't
supported in libbpf, this commit fixes this problem by correcting the
section header.
$ sudo ./test_cgrp2_sock2.sh
libbpf: prog 'bpf_prog1': missing BPF prog type, check ELF section name 'cgroup/sock1'
libbpf: prog 'bpf_prog1': failed to load: -22
libbpf: failed to load object './sock_flags_kern.o'
ERROR: loading BPF object file failed
In addition, this BPF program filters ping packets by comparing whether
the socket type uses SOCK_RAW. However, after the ICMP socket[1] was
developed, ping sends ICMP packets using SOCK_DGRAM. Therefore, in this
commit, the packet filtering is changed to use SOCK_DGRAM instead of
SOCK_RAW.
$ strace --trace socket ping -6 -c1 -w1 ::1
socket(AF_INET6, SOCK_DGRAM, IPPROTO_ICMPV6) = 3
[1]: https://lwn.net/Articles/422330/
Signed-off-by: Daniel T. Lee <danieltimlee@xxxxxxxxx>
---
samples/bpf/sock_flags_kern.c | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)
diff --git a/samples/bpf/sock_flags_kern.c b/samples/bpf/sock_flags_kern.c
index 6d0ac7569d6f..1d58cb9b6fa4 100644
--- a/samples/bpf/sock_flags_kern.c
+++ b/samples/bpf/sock_flags_kern.c
@@ -5,7 +5,7 @@
#include <uapi/linux/in6.h>
#include <bpf/bpf_helpers.h>
-SEC("cgroup/sock1")
+SEC("cgroup/sock")
int bpf_prog1(struct bpf_sock *sk)
{
char fmt[] = "socket: family %d type %d protocol %d\n";
@@ -17,29 +17,29 @@ int bpf_prog1(struct bpf_sock *sk)
bpf_trace_printk(fmt, sizeof(fmt), sk->family, sk->type, sk->protocol);
bpf_trace_printk(fmt2, sizeof(fmt2), uid, gid);
- /* block PF_INET6, SOCK_RAW, IPPROTO_ICMPV6 sockets
+ /* block PF_INET6, SOCK_DGRAM, IPPROTO_ICMPV6 sockets
* ie., make ping6 fail
*/
if (sk->family == PF_INET6 &&
- sk->type == SOCK_RAW &&
+ sk->type == SOCK_DGRAM &&
sk->protocol == IPPROTO_ICMPV6)
return 0;
return 1;
}
-SEC("cgroup/sock2")
+SEC("cgroup/sock")
int bpf_prog2(struct bpf_sock *sk)
{
char fmt[] = "socket: family %d type %d protocol %d\n";
bpf_trace_printk(fmt, sizeof(fmt), sk->family, sk->type, sk->protocol);
- /* block PF_INET, SOCK_RAW, IPPROTO_ICMP sockets
+ /* block PF_INET, SOCK_DGRAM, IPPROTO_ICMP sockets
* ie., make ping fail
*/
if (sk->family == PF_INET &&
- sk->type == SOCK_RAW &&
+ sk->type == SOCK_DGRAM &&
sk->protocol == IPPROTO_ICMP)
return 0;
--
2.34.1
