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 #include <bpf/bpf_tracing.h>
7 
8 char _license[] SEC("license") = "GPL";
9 
10 static __attribute__((noinline)) struct inode *SOCK_INODE(struct socket *socket)
11 {
12 	return &container_of(socket, struct socket_alloc, socket)->vfs_inode;
13 }
14 
15 SEC("iter/netlink")
16 int dump_netlink(struct bpf_iter__netlink *ctx)
17 {
18 	struct seq_file *seq = ctx->meta->seq;
19 	struct netlink_sock *nlk = ctx->sk;
20 	unsigned long group, ino;
21 	struct inode *inode;
22 	struct socket *sk;
23 	struct sock *s;
24 
25 	if (nlk == (void *)0)
26 		return 0;
27 
28 	if (ctx->meta->seq_num == 0)
29 		BPF_SEQ_PRINTF(seq, "sk               Eth Pid        Groups   "
30 				    "Rmem     Wmem     Dump  Locks    Drops    "
31 				    "Inode\n");
32 
33 	s = &nlk->sk;
34 	BPF_SEQ_PRINTF(seq, "%pK %-3d ", s, s->sk_protocol);
35 
36 	if (!nlk->groups)  {
37 		group = 0;
38 	} else {
39 		/* FIXME: temporary use bpf_probe_read_kernel here, needs
40 		 * verifier support to do direct access.
41 		 */
42 		bpf_probe_read_kernel(&group, sizeof(group), &nlk->groups[0]);
43 	}
44 	BPF_SEQ_PRINTF(seq, "%-10u %08x %-8d %-8d %-5d %-8d ",
45 		       nlk->portid, (u32)group,
46 		       s->sk_rmem_alloc.counter,
47 		       s->sk_wmem_alloc.refs.counter - 1,
48 		       nlk->cb_running, s->sk_refcnt.refs.counter);
49 
50 	sk = s->sk_socket;
51 	if (!sk) {
52 		ino = 0;
53 	} else {
54 		/* FIXME: container_of inside SOCK_INODE has a forced
55 		 * type conversion, and direct access cannot be used
56 		 * with current verifier.
57 		 */
58 		inode = SOCK_INODE(sk);
59 		bpf_probe_read_kernel(&ino, sizeof(ino), &inode->i_ino);
60 	}
61 	BPF_SEQ_PRINTF(seq, "%-8u %-8lu\n", s->sk_drops.counter, ino);
62 
63 	return 0;
64 }
65