// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2020 Facebook */
#include <vmlinux.h>
#include "bpf_tracing_net.h"
#include <bpf/bpf_helpers.h>

char _license[] SEC("license") = "GPL";

static __attribute__((noinline)) struct inode *SOCK_INODE(struct socket *socket)
{
        return &container_of(socket, struct socket_alloc, socket)->vfs_inode;
}

SEC("iter/netlink")
int dump_netlink(struct bpf_iter__netlink *ctx)
{
        struct seq_file *seq = ctx->meta->seq;
        struct netlink_sock *nlk = ctx->sk;
        unsigned long group, ino;
        struct inode *inode;
        struct socket *sk;
        struct sock *s;

        if (nlk == (void *)0)
                return 0;

        if (ctx->meta->seq_num == 0)
                BPF_SEQ_PRINTF(seq, "sk               Eth Pid        Groups   "
                                    "Rmem     Wmem     Dump  Locks    Drops    "
                                    "Inode\n");

        s = &nlk->sk;
        BPF_SEQ_PRINTF(seq, "%pK %-3d ", s, s->sk_protocol);

        if (!nlk->groups)  {
                group = 0;
        } else {
                /* FIXME: temporary use bpf_probe_read_kernel here, needs
                 * verifier support to do direct access.
                 */
                bpf_probe_read_kernel(&group, sizeof(group), &nlk->groups[0]);
        }
        BPF_SEQ_PRINTF(seq, "%-10u %08x %-8d %-8d %-5d %-8d ",
                       nlk->portid, (u32)group,
                       s->sk_rmem_alloc.counter,
                       s->sk_wmem_alloc.refs.counter - 1,
                       nlk->cb_running, s->sk_refcnt.refs.counter);

        sk = s->sk_socket;
        if (!sk) {
                ino = 0;
        } else {
                /* FIXME: container_of inside SOCK_INODE has a forced
                 * type conversion, and direct access cannot be used
                 * with current verifier.
                 */
                inode = SOCK_INODE(sk);
                bpf_probe_read_kernel(&ino, sizeof(ino), &inode->i_ino);
        }
        BPF_SEQ_PRINTF(seq, "%-8u %-8lu\n", s->sk_drops.counter, ino);

        return 0;
}