#!/bin/bash
# Name: ipfn
# Version: 1.0.7
# Date: 2026-01-22
# Description: Default to list, auto-test on add, skip test with -f, and port collision warning.

# sudo権限チェック
if [ "$(id -u)" -ne 0 ]; then
    exec sudo "$0" "$@"
fi

TABLE_NAME="ipf_wrapper"
PROTO="tcp"
FORCE_FLAG=false
SKIP_TEST=false

# --- 初期化 ---
init_nft() {
    nft add table inet ${TABLE_NAME} 2>/dev/null
    nft add chain inet ${TABLE_NAME} prerouting { type nat hook prerouting priority -100 \; } 2>/dev/null
    nft add chain inet ${TABLE_NAME} output { type nat hook output priority -100 \; } 2>/dev/null
    nft add chain inet ${TABLE_NAME} postrouting { type nat hook postrouting priority 100 \; } 2>/dev/null
    nft add chain inet ${TABLE_NAME} forward { type filter hook forward priority 0 \; policy accept \; } 2>/dev/null
}

# --- ルール表示 (アスタリスク強調) ---
list_rules() {
    local highlight_uuid=$1
    init_nft
    echo "Forwarding Rules (ipfn):"
    printf "%-10s %-6s %-20s %-20s %-10s\n" "HANDLE" "PROTO" "LOCAL" "TARGET" "UUID"
    echo "-----------------------------------------------------------------------------------"
    
    nft -a list chain inet ${TABLE_NAME} prerouting | grep "dnat" | while read -r line; do
        handle=$(echo "$line" | grep -o 'handle [0-9]*' | awk '{print $2}')
        proto=$(echo "$line" | grep -q "udp" && echo "udp" || echo "tcp")
        target=$(echo "$line" | grep -oE '[0-9.]*:[0-9]+' | head -n 1)
        lport=$(echo "$line" | grep -o 'dport [0-9]*' | awk '{print $2}')
        full_uuid=$(echo "$line" | grep -o 'ipf-id:[a-z0-9-]*' | cut -d':' -f2)
        
        if [[ -n "$highlight_uuid" && "$full_uuid" == "$highlight_uuid" ]]; then
            printf "\e[1;36m*%-9s %-6s %-20s %-20s %-10s\e[0m\n" "$handle" "$proto" ":$lport" "$target" "${full_uuid:0:8}"
        else
            printf "%-10s %-6s %-20s %-20s %-10s\n" "$handle" "$proto" ":$lport" "$target" "${full_uuid:0:8}"
        fi
    done
}

# --- 疎通確認 ---
test_rule_by_port() {
    local lp=$1
    echo -n "Testing connectivity to :$lp... "
    if nc -z -v -w 2 127.0.0.1 "$lp" 2>&1 | grep -E "succeeded|connected|open" >/dev/null; then
        echo -e "\e[32mOK\e[0m"
    else
        echo -e "\e[31mFAILED\e[0m"
    fi
}

# --- ルール追加 ---
add_rule() {
    init_nft
    local port_ip_port=$1
    local local_port=$(echo "$port_ip_port" | cut -d':' -f1)
    local target_ip=$(echo "$port_ip_port" | cut -d':' -f2)
    local target_port=$(echo "$port_ip_port" | cut -d':' -f3)

    # 重複チェック (警告のみ)
    if nft list chain inet ${TABLE_NAME} prerouting | grep -q "dport $local_port"; then
        echo -e "\e[33mWarning: Port :$local_port is already in use by another rule.\e[0m"
    fi

    local raw_uuid=$(cat /proc/sys/kernel/random/uuid)
    local uuid="ipf-id:$raw_uuid"
    local comment="comment \"$uuid\""
    local family="ip"
    [[ "$target_ip" =~ : ]] && family="ip6"

    nft add rule inet ${TABLE_NAME} prerouting "$PROTO" dport "$local_port" dnat $family to "$target_ip:$target_port" "$comment"
    nft add rule inet ${TABLE_NAME} output "$PROTO" dport "$local_port" dnat $family to "$target_ip:$target_port" "$comment"
    nft add rule inet ${TABLE_NAME} forward iifname "lo" accept "$comment"
    nft add rule inet ${TABLE_NAME} forward $family daddr "$target_ip" "$PROTO" dport "$target_port" ct state new,established,related accept "$comment"
    nft add rule inet ${TABLE_NAME} forward $family saddr "$target_ip" "$PROTO" sport "$target_port" ct state established,related accept "$comment"
    nft add rule inet ${TABLE_NAME} postrouting $family daddr "$target_ip" "$PROTO" dport "$target_port" masquerade "$comment"

    echo "ipfn: Rule added."
    echo ""
    list_rules "$raw_uuid"
    
    # 自動テスト
    if [[ "$SKIP_TEST" == false ]]; then
        echo ""
        test_rule_by_port "$local_port"
    fi
}

# --- ルール削除 ---
delete_rule() {
    init_nft
    local handle=$1
    local rule_info=$(nft -a list chain inet ${TABLE_NAME} prerouting | grep "handle $handle")
    [[ -z "$rule_info" ]] && { echo "Error: Handle $handle not found."; exit 1; }

    local uuid=$(echo "$rule_info" | grep -o 'ipf-id:[a-z0-9-]*' | head -n 1)
    local lp=$(echo "$rule_info" | grep -o 'dport [0-9]*' | awk '{print $2}')
    local tg=$(echo "$rule_info" | grep -oE '[0-9.]*:[0-9]+' | head -n 1)

    if [[ "$FORCE_FLAG" == false ]]; then
        echo "Delete Handle $handle (:$lp -> $tg)?"
        echo -n "Are you sure? (y/N): "
        read -r confirm
        [[ ! "$confirm" =~ ^[yY]$ ]] && { echo "Aborted."; exit 0; }
    fi

    for chain in prerouting output forward postrouting; do
        nft -a list chain inet ${TABLE_NAME} "$chain" | grep "$uuid" | grep -o 'handle [0-9]*' | awk '{print $2}' | while read -r h; do
            nft delete rule inet ${TABLE_NAME} "$chain" handle "$h"
        done
    done
    echo "ipfn: Deleted."; echo ""; list_rules
}

# --- メインパース ---
# 先にフラグをスキャン
for arg in "$@"; do
    [[ "$arg" == "-f" ]] && FORCE_FLAG=true && SKIP_TEST=true
done

if [[ $# -eq 0 ]]; then
    list_rules
    exit 0
fi

while [[ $# -gt 0 ]]; do
    case "$1" in
        -L|-l) list_rules; exit 0 ;;
        -df*|-d*)
            [[ "$1" == -df* ]] && FORCE_FLAG=true
            h="${1#-df}"; h="${h#-d}"
            [[ -z "$h" ]] && { h="$2"; shift; }
            delete_rule "$h"; exit 0 ;;
        -t*)
            h="${1#-t}"
            [[ -z "$h" ]] && { h="$2"; shift; }
            # ハンドルからポートを引いてテスト
            lp=$(nft -a list chain inet ${TABLE_NAME} prerouting | grep "handle $h" | grep -o 'dport [0-9]*' | awk '{print $2}')
            test_rule_by_port "$lp"; exit 0 ;;
        -f) # 単体実行時はカーネル設定
            if [[ $# -eq 1 ]]; then
                sysctl -w net.ipv4.ip_forward=1 >/dev/null
                sysctl -w net.ipv4.conf.all.route_localnet=1 >/dev/null
                echo "Kernel parameters updated."
                exit 0
            fi ;;
        *)
            if [[ "$1" =~ ^[0-9]+: ]]; then
                add_rule "$1"
                exit 0
            fi ;;
    esac
    shift
done