// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2020 Facebook */
#include <vmlinux.h>
#include "bpf_tracing_net.h"
#include <bpf/bpf_helpers.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,
                       udp_sk->drop_counters.drops0.counter +
                       udp_sk->drop_counters.drops1.counter);
        return 0;
}