3.Firewall[tabela_NAT]

# !/bin/bash

###################
##### Funcoes #####
###################

# Comando: Desativando Firewall
Configuracoes()
{
    # Tabela: NAT
    iptables -t nat -P INPUT ACCEPT
    iptables -t nat -P OUTPUT ACCEPT
    iptables -t nat -P FORWARD ACCEPT
}

Regra_Lista()
{
    # Apresentacao
    clear
    echo ""
    echo -e "\033[01;37m ---------------------- \033[01;37m"
    echo -e "\033[01;36m * Listagem de regras * \033[01;37m"
    echo -e "\033[01;37m ---------------------- \033[01;37m"
    echo -e ""

    # Comando: Listagem de regras detalhadas + sequencia
    iptables -t nat -nvL --line-number
    echo -e "\n\033[01;31m --------------------------------------------------------------------- \033[01;37m\n"

    # Comando: Listagem de regras em sequencia
    iptables -t nat -L --line-number
    echo -e "\n\033[01;31m --------------------------------------------------------------------- \033[01;37m\n"
}

Regra_Limpeza()
{
    # Apresentacao
    clear
    echo ""
    echo -e "\033[01;37m ---------------------- \033[01;37m"
    echo -e "\033[01;36m * Regras reiniciadas * \033[01;37m"
    echo -e "\033[01;37m ---------------------- \033[01;37m"
    echo ""

    # Comando: Limpando memoria [flush]
    iptables -t nat -X
    iptables -t nat -F
}

Regra_Deletar()
{
    # Apresentacao
    clear
    echo ""
    echo -e "\033[01;37m -------------------- \033[01;37m"
    echo -e "\033[01;36m * Delecao de regra * \033[01;37m"
    echo -e "\033[01;37m -------------------- \033[01;37m"
    echo ""

    # Entrada de dados
    echo -e -n "\033[01;35m - Posicao: \033[01;37m"
    read pos

    # Comando: Deletar regra pela posicao
    iptables -t nat -D POSTROUTING $pos
    iptables -t nat -D PREROUTING $pos
}

Liberar_Internet()
{
    # Apresentacao
    clear
    echo ""
    echo -e "\033[01;37m -------------------- \033[01;37m"
    echo -e "\033[01;36m * Liberar Internet * \033[01;37m"
    echo -e "\033[01;37m -------------------- \033[01;37m"
    echo ""

    # Entrada de dados
    echo -e "\033[01;36m * Interface * \033[01;37m"
    ifconfig
    echo ""

    # Entrada de dados
    echo -e -n "\033[01;35m - Interface de rede: \033[01;37m"
    read interface

    # Comando: Deletar regra pela posicao
    iptables -t nat -A POSTROUTING -o $interface -j MASQUERADE
    echo "1" > /proc/sys/net/ipv4/ip_forward
}

Redirecionamento_Porta()
{
    # Apresentacao
    clear
    echo ""
    echo -e "\033[01;37m ------------------------------ \033[01;37m"
    echo -e "\033[01;36m * Redirecionamento de portas * \033[01;37m"
    echo -e "\033[01;37m ------------------------------ \033[01;37m"
    echo ""

    # IP [destino] = Nossa maquina
    echo -e -n "\033[01;36m - IP [destino]: \033[01;37m"
    read ip_destino
    echo ""

    # Porta origem = 22
    echo -e -n "\033[01;36m - Porta [servico]: \033[01;37m"
    read porta_servico
    echo ""

    # IP [origem] = Maquina alvo
    echo -e -n "\033[01;36m - IP [origem]: \033[01;37m"
    read ip_origem
    echo ""

    # Porta Alvo = 2200
    echo -e -n "\033[01;36m - Porta [mascarada]: \033[01;37m"
    read porta_mascarada
    echo ""

    # Comando: Redirecionamento de porta
    iptables -t nat -A PREROUTING -d $ip_destino -p TCP --dport $porta_mascarada -j DNAT --to $ip_origem:$porta_servico
}

####################
##### IPTABLES #####
####################

# Configuracao
Configuracoes

# Estrutura em loop
while (( 1 ))
do
    # Menu
    clear
    echo -e "\033[01;36m --------------- DATA --------------- \033[01;37m"
    echo -e "\033[01;32m * Num: $(date +%d)           \033[01;37m"
    echo -e "\033[01;31m * Dia: $(date +%a)           \033[01;37m"
    echo -e "\033[01;33m * Mes: $(date +%b)           \033[01;37m"
    echo -e "\033[01;35m * Ano: $(date +%Y)           \033[01;37m"
    echo -e "\033[01;36m ------------------------------------ \033[01;37m"
    echo ""
    echo -e "\033[01;37m ################################# FIREWALL ################################## \033[01;37m\n"
    echo -e "\033[01;33m [1]  Regras [lista]                                   \033[01;37m"
    echo -e "\033[01;33m [2]  Regras [limpeza]                                     \033[01;37m"
    echo -e "\033[01;33m [3]  Regras [deletar]                                 \033[01;37m"
    echo -e ""
    echo -e "\033[01;34m [4] Liberar [internet]                                \033[01;37m"
    echo -e "\033[01;35m [5] Redirecionamento [porta]                          \033[01;37m"
    echo ""
    echo -e "\033[01;37m ############################################################################# \033[01;37m\n"
    echo -e -n "\n\033[01;34m + Opc: \033[01;37m"
    read opc
    echo ""

    # Estrutura em escolha
    case $opc in
    1)
        Regra_Lista;;

    2)
        Regra_Limpeza;;

    3)
        Regra_Deletar;;

    4)
        Liberar_Internet;;

    5)
        Redirecionamento_Porta;;

    *)
        ;;
    esac

    echo -e "\n\033[01;32m =-=-= Press [ENTER] =-=-= \033[01;37m\n"
    read
done