Re: [PATCH v3 bpf-next 2/2] selftest/bpf: Implement sample UNIX domain socket iterator program.
From: Andrii Nakryiko <hidden>
Date: 2021-08-06 23:33:37
Also in:
bpf
On Wed, Aug 4, 2021 at 12:09 AM Kuniyuki Iwashima [off-list ref] wrote:
If there are no abstract sockets, this prog can output the same result compared to /proc/net/unix. # cat /sys/fs/bpf/unix | head -n 2 Num RefCount Protocol Flags Type St Inode Path ffff9ab7122db000: 00000002 00000000 00010000 0001 01 10623 private/defer # cat /proc/net/unix | head -n 2 Num RefCount Protocol Flags Type St Inode Path ffff9ab7122db000: 00000002 00000000 00010000 0001 01 10623 private/defer According to the analysis by Yonghong Song (See the link), the BPF verifier cannot load the code in the comment to print the name of the abstract UNIX domain socket due to LLVM optimisation. It can be uncommented once the LLVM code gen is improved. Link: https://lore.kernel.org/netdev/1994df05-8f01-371f-3c3b-d33d7836878c@fb.com/ (local)
Our patchworks tooling, used to apply patches, is using Link: tag to record original discussion, so this will be quite confusing if you use the same "Link: " for referencing relevant discussions. Please use standard link reference syntax: According to the analysis by Yonghong Song ([0]), ... ... [0] https://lore.kernel.org/netdev/1994df05-8f01-371f-3c3b-d33d7836878c@fb.com/ (local)
Signed-off-by: Kuniyuki Iwashima <redacted> --- .../selftests/bpf/prog_tests/bpf_iter.c | 16 ++++ tools/testing/selftests/bpf/progs/bpf_iter.h | 8 ++ .../selftests/bpf/progs/bpf_iter_unix.c | 86 +++++++++++++++++++ .../selftests/bpf/progs/bpf_tracing_net.h | 4 + 4 files changed, 114 insertions(+) create mode 100644 tools/testing/selftests/bpf/progs/bpf_iter_unix.c
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quoted hunk ↗ jump to hunk
diff --git a/tools/testing/selftests/bpf/progs/bpf_iter.h b/tools/testing/selftests/bpf/progs/bpf_iter.h index 3d83b185c4bc..d92648621bcb 100644 --- a/tools/testing/selftests/bpf/progs/bpf_iter.h +++ b/tools/testing/selftests/bpf/progs/bpf_iter.h@@ -12,6 +12,7 @@ #define tcp6_sock tcp6_sock___not_used #define bpf_iter__udp bpf_iter__udp___not_used #define udp6_sock udp6_sock___not_used +#define bpf_iter__unix bpf_iter__unix___not_used #define bpf_iter__bpf_map_elem bpf_iter__bpf_map_elem___not_used #define bpf_iter__bpf_sk_storage_map bpf_iter__bpf_sk_storage_map___not_used #define bpf_iter__sockmap bpf_iter__sockmap___not_used@@ -32,6 +33,7 @@ #undef tcp6_sock #undef bpf_iter__udp #undef udp6_sock +#undef bpf_iter__unix #undef bpf_iter__bpf_map_elem #undef bpf_iter__bpf_sk_storage_map #undef bpf_iter__sockmap@@ -103,6 +105,12 @@ struct udp6_sock { struct ipv6_pinfo inet6; } __attribute__((preserve_access_index)); +struct bpf_iter__unix { + struct bpf_iter_meta *meta; + struct unix_sock *unix_sk; + uid_t uid __attribute__((aligned(8)));
just fyi, aligned doesn't matter here, CO-RE will relocate offsets appropriately anyways
+} __attribute__((preserve_access_index));
+
struct bpf_iter__bpf_map_elem {
struct bpf_iter_meta *meta;
struct bpf_map *map;[...]
+SEC("iter/unix")
+int dump_unix(struct bpf_iter__unix *ctx)
+{
+ struct unix_sock *unix_sk = ctx->unix_sk;
+ struct sock *sk = (struct sock *)unix_sk;
+ struct seq_file *seq;
+ __u32 seq_num;
+
+ if (!unix_sk)
+ return 0;
+
+ seq = ctx->meta->seq;
+ seq_num = ctx->meta->seq_num;
+ if (seq_num == 0)
+ BPF_SEQ_PRINTF(seq, "Num RefCount Protocol Flags "
+ "Type St Inode Path\n");nit: please keep format strings on a single line
+ + BPF_SEQ_PRINTF(seq, "%pK: %08X %08X %08X %04X %02X %5lu", + unix_sk, + sk->sk_refcnt.refs.counter, + 0, + sk->sk_state == TCP_LISTEN ? __SO_ACCEPTCON : 0, + sk->sk_type, + sk->sk_socket ? + (sk->sk_state == TCP_ESTABLISHED ? SS_CONNECTED : SS_UNCONNECTED) : + (sk->sk_state == TCP_ESTABLISHED ? SS_CONNECTING : SS_DISCONNECTING), + sock_i_ino(sk)); +
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