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

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

#define IPV6_SEQ_DGRAM_HEADER				\
	"  sl  "					\
	"local_address                         "	\
	"remote_address                        "	\
	"st tx_queue rx_queue tr tm->when retrnsmt"	\
	"   uid  timeout inode ref pointer drops\n"

static long sock_i_ino(const struct sock *sk)
{
	const struct socket *sk_socket = sk->sk_socket;
	const struct inode *inode;
	unsigned long ino;

	if (!sk_socket)
		return 0;

	inode = &container_of(sk_socket, struct socket_alloc, socket)->vfs_inode;
	bpf_probe_read_kernel(&ino, sizeof(ino), &inode->i_ino);
	return ino;
}

SEC("iter/udp")
int dump_udp6(struct bpf_iter__udp *ctx)
{
	struct seq_file *seq = ctx->meta->seq;
	struct udp_sock *udp_sk = ctx->udp_sk;
	const struct in6_addr *dest, *src;
	struct udp6_sock *udp6_sk;
	struct inet_sock *inet;
	__u16 srcp, destp;
	__u32 seq_num;
	int rqueue;

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

	seq_num = ctx->meta->seq_num;
	if (seq_num == 0)
		BPF_SEQ_PRINTF(seq, IPV6_SEQ_DGRAM_HEADER);

	udp6_sk = bpf_skc_to_udp6_sock(udp_sk);
	if (udp6_sk == (void *)0)
		return 0;

	inet = &udp_sk->inet;
	srcp = bpf_ntohs(inet->inet_sport);
	destp = bpf_ntohs(inet->inet_dport);
	rqueue = inet->sk.sk_rmem_alloc.counter - udp_sk->forward_deficit;
	dest  = &inet->sk.sk_v6_daddr;
	src   = &inet->sk.sk_v6_rcv_saddr;

	BPF_SEQ_PRINTF(seq, "%5d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X ",
		       ctx->bucket,
		       src->s6_addr32[0], src->s6_addr32[1],
		       src->s6_addr32[2], src->s6_addr32[3], srcp,
		       dest->s6_addr32[0], dest->s6_addr32[1],
		       dest->s6_addr32[2], dest->s6_addr32[3], destp);

	BPF_SEQ_PRINTF(seq, "%02X %08X:%08X %02X:%08lX %08X %5u %8d %lu %d %pK %u\n",
		       inet->sk.sk_state,
		       inet->sk.sk_wmem_alloc.refs.counter - 1,
		       rqueue,
		       0, 0L, 0, ctx->uid, 0,
		       sock_i_ino(&inet->sk),
		       inet->sk.sk_refcnt.refs.counter, udp_sk,
		       inet->sk.sk_drops.counter);

	return 0;
}