ipf/ipfn1.0

#!/bin/bash
# Name: ipfn
# Version: 1.1.9
# Date: 2026-01-22
# Description: Fixed syntax error and finalized safety guards.

if [ "$(id -u)" -ne 0 ]; then
    exec sudo "$0" "$@"
fi

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

# --- 1. Utility Functions ---

msg() { [[ "$QUIET_MODE" == false ]] && echo -e "$@"; }

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
}

show_help() {
    echo "Usage: ipfn [OPTIONS] [PORT:TARGET_IP:TARGET_PORT]"
    echo ""
    echo "Options:"
    echo "  -l, -L         List all rules"
    echo "  -d HANDLE/:PORT Delete by handle or port (e.g., -d 17 or -d :80)"
    echo "  -df, -qd       Force/Quiet delete"
    echo "  -t [HANDLE]    Test connectivity"
    echo "  -f             Skip test / Enable IP forward"
    echo "  -v             Show raw nftables rules"
    echo "  -h             Show this help"
}

list_rules() {
    [[ "$QUIET_MODE" == true ]] && return
    local highlight_uuid=$1
    init_nft
    msg "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
}

test_rule_by_port() {
    [[ "$QUIET_MODE" == true ]] && return
    local lp=$1
    echo -n "Testing connectivity to :$lp... "
    if nc -z -v -w 2 127.0.0.1 "$lp" 2>&1 | grep -iqE "succeeded|connected|open"; then
        echo -e "\e[32mOK\e[0m"
    else
        echo -e "\e[31mFAILED\e[0m"
    fi
}

validate_prerouting_handle() {
    nft -a list chain inet ${TABLE_NAME} prerouting | grep -q "handle $1"
}

parse_delete_targets() {
    local input=$1
    local -a final_handles=()
    IFS=',' read -r -a parts <<< "$input"
    for part in "${parts[@]}"; do
        if [[ "$part" =~ ^:([0-9]+)$ ]]; then
            local target_port="${BASH_REMATCH[1]}"
            local found_h=$(nft -a list chain inet ${TABLE_NAME} prerouting | grep "dport $target_port" | grep -o 'handle [0-9]*' | awk '{print $2}')
            for h in $found_h; do final_handles+=("$h"); done
        elif [[ "$part" =~ ^([0-9]+)-([0-9]+)$ ]]; then
            for ((i=${BASH_REMATCH[1]}; i<=${BASH_REMATCH[2]}; i++)); do
                validate_prerouting_handle "$i" && final_handles+=("$i")
            done
        else
            validate_prerouting_handle "$part" && final_handles+=("$part")
        fi
    done
    echo "${final_handles[@]}"
}

add_rule() {
    init_nft
    local lp=$(echo "$1" | cut -d':' -f1)
    local tip=$(echo "$1" | cut -d':' -f2)
    local tp=$(echo "$1" | cut -d':' -f3)
    [[ "$QUIET_MODE" == false ]] && nft list chain inet ${TABLE_NAME} prerouting | grep -q "dport $lp" && msg "\e[33mWarning: Port :$lp is already in use.\e[0m"
    local raw_uuid=$(cat /proc/sys/kernel/random/uuid)
    local uuid="ipf-id:$raw_uuid"
    local family="ip"; [[ "$tip" =~ : ]] && family="ip6"
    nft add rule inet ${TABLE_NAME} prerouting "$PROTO" dport "$lp" dnat $family to "$tip:$tp" comment "\"$uuid\""
    nft add rule inet ${TABLE_NAME} output "$PROTO" dport "$lp" dnat $family to "$tip:$tp" comment "\"$uuid\""
    nft add rule inet ${TABLE_NAME} forward iifname "lo" accept comment "\"$uuid\""
    nft add rule inet ${TABLE_NAME} forward $family daddr "$tip" "$PROTO" dport "$tp" ct state new,established,related accept comment "\"$uuid\""
    nft add rule inet ${TABLE_NAME} forward $family saddr "$tip" "$PROTO" sport "$tp" ct state established,related accept comment "\"$uuid\""
    nft add rule inet ${TABLE_NAME} postrouting $family daddr "$tip" "$PROTO" dport "$tp" masquerade comment "\"$uuid\""
    list_rules "$raw_uuid"
    [[ "$SKIP_TEST" == false ]] && { echo ""; test_rule_by_port "$lp"; }
}

# --- 2. Main Logic ---

# Pre-scan flags
for arg in "$@"; do
    [[ "$arg" =~ q ]] && QUIET_MODE=true && FORCE_FLAG=true && SKIP_TEST=true
    [[ "$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
        -h|--help) show_help; exit 0 ;;
        -v|--verbose) nft list table inet ${TABLE_NAME}; exit 0 ;;
        -L|-l) list_rules; exit 0 ;;
        -f)
            if [[ $# -eq 1 ]]; then
                sysctl -w net.ipv4.ip_forward=1 >/dev/null
                sysctl -w net.ipv4.conf.all.route_localnet=1 >/dev/null
                msg "Kernel parameters updated."; exit 0
            fi ;;
        -t*)
            h_str="${1#-t}"
            if [[ -z "$h_str" && ( "$2" =~ ^[0-9,-]+$ ) ]]; then h_str="$2"; shift; fi
            if [[ -z "$h_str" ]]; then
                count=$(nft list chain inet ${TABLE_NAME} prerouting | grep -c "dnat")
                if [ "$count" -eq 1 ]; then
                    h_str=$(nft -a list chain inet ${TABLE_NAME} prerouting | grep "handle" | awk '{print $NF}')
                else
                    msg "Error: Multiple rules exist. Specify a handle."; exit 1
                fi
            fi
            lp=$(nft -a list chain inet ${TABLE_NAME} prerouting | grep "handle $h_str" | grep -o 'dport [0-9]*' | awk '{print $2}')
            [[ -n "$lp" ]] && test_rule_by_port "$lp" || msg "Error: Handle $h_str not found."
            exit 0 ;;
        -*[d]*)
            h_str=$(echo "$1" | sed -E 's/^-q?d?f?//')
            [[ -z "$h_str" ]] && { h_str="$2"; shift; }
            handles=($(parse_delete_targets "$h_str"))
            if [[ ${#handles[@]} -eq 0 ]]; then
                msg "No valid prerouting handles found."; exit 1
            fi
            if [[ "$FORCE_FLAG" == false ]]; then
                msg "Review rules to delete (Top-level only):"
                for h in "${handles[@]}"; do
                    nft -a list chain inet ${TABLE_NAME} prerouting | grep "handle $h" | sed 's/^/  /'
                done
                read -p "Delete these rules and their sub-rules? (y/N): " confirm
                [[ ! "$confirm" =~ ^[yY]$ ]] && exit 0
            fi
            for h in "${handles[@]}"; do
                ri=$(nft -a list chain inet ${TABLE_NAME} prerouting | grep "handle $h")
                [[ -z "$ri" ]] && continue
                uuid=$(echo "$ri" | grep -o 'ipf-id:[a-z0-9-]*' | head -n 1)
                for c in prerouting output forward postrouting; do
                    nft -a list chain inet ${TABLE_NAME} "$c" | grep "$uuid" | grep -o 'handle [0-9]*' | awk '{print $2}' | while read -r rh; do
                        nft delete rule inet ${TABLE_NAME} "$c" handle "$rh"
                    done
                done
                msg "Deleted associated with handle $h"
            done
            list_rules; exit 0 ;;
        *)
            if [[ "$1" =~ ^[0-9]+: ]]; then add_rule "$1"; exit 0
            else msg "\e[31mError: Unknown option '$1'\e[0m\n"; show_help; exit 1; fi ;;
    esac
    shift
done