xref: /linux/tools/testing/selftests/bpf/progs/bpf_iter_netlink.c (revision 8ca4fc323d2e4ab9dabbdd57633af40b0c7e6af9)
1 // SPDX-License-Identifier: GPL-2.0
2 /* Copyright (c) 2020 Facebook */
3 #include "bpf_iter.h"
4 #include "bpf_tracing_net.h"
5 #include <bpf/bpf_helpers.h>
6 
7 char _license[] SEC("license") = "GPL";
8 
9 static __attribute__((noinline)) struct inode *SOCK_INODE(struct socket *socket)
10 {
11 	return &container_of(socket, struct socket_alloc, socket)->vfs_inode;
12 }
13 
14 SEC("iter/netlink")
15 int dump_netlink(struct bpf_iter__netlink *ctx)
16 {
17 	struct seq_file *seq = ctx->meta->seq;
18 	struct netlink_sock *nlk = ctx->sk;
19 	unsigned long group, ino;
20 	struct inode *inode;
21 	struct socket *sk;
22 	struct sock *s;
23 
24 	if (nlk == (void *)0)
25 		return 0;
26 
27 	if (ctx->meta->seq_num == 0)
28 		BPF_SEQ_PRINTF(seq, "sk               Eth Pid        Groups   "
29 				    "Rmem     Wmem     Dump  Locks    Drops    "
30 				    "Inode\n");
31 
32 	s = &nlk->sk;
33 	BPF_SEQ_PRINTF(seq, "%pK %-3d ", s, s->sk_protocol);
34 
35 	if (!nlk->groups)  {
36 		group = 0;
37 	} else {
38 		/* FIXME: temporary use bpf_probe_read_kernel here, needs
39 		 * verifier support to do direct access.
40 		 */
41 		bpf_probe_read_kernel(&group, sizeof(group), &nlk->groups[0]);
42 	}
43 	BPF_SEQ_PRINTF(seq, "%-10u %08x %-8d %-8d %-5d %-8d ",
44 		       nlk->portid, (u32)group,
45 		       s->sk_rmem_alloc.counter,
46 		       s->sk_wmem_alloc.refs.counter - 1,
47 		       nlk->cb_running, s->sk_refcnt.refs.counter);
48 
49 	sk = s->sk_socket;
50 	if (!sk) {
51 		ino = 0;
52 	} else {
53 		/* FIXME: container_of inside SOCK_INODE has a forced
54 		 * type conversion, and direct access cannot be used
55 		 * with current verifier.
56 		 */
57 		inode = SOCK_INODE(sk);
58 		bpf_probe_read_kernel(&ino, sizeof(ino), &inode->i_ino);
59 	}
60 	BPF_SEQ_PRINTF(seq, "%-8u %-8lu\n", s->sk_drops.counter, ino);
61 
62 	return 0;
63 }
64