Sub-rede de roteamento para tabela de roteamento específica com fwmark, direto para ISP e VPN

Question

Sub-rede de roteamento para tabela de roteamento específica com fwmark, direto para ISP e VPN

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2

Introdução

Estou tentando configurar uma VPN no meu roteador para ter duas tabelas de roteamento. Eu quero isso para que toda a filtragem seja feita com o iptables, e o iproute apenas atue nas fwmarks específicas, ou seja, regras genéricas.

É uma melhoria de Como encaminhar uma sub-rede específica para um túnel de VPN

A configuração atual de trabalho deste projeto completo pode ser encontrada

link

O principal problema com essa solução enquanto funciona e eu estou usando atualmente requer filtragem no iptables e nas regras de ip e, portanto, não é muito flexível.

A idéia é que os pacotes marcados com 1 saiam diretamente do ppp0, e os pacotes marcados com 2 passem pelo tun0.

Resumo

A tabela do ISP encaminha todo o tráfego de 192.168.1.0/24 para fora ppp0
A tabela VPN roteia todo o tráfego de 192.168.2.0/24 para fora tun0

Diagrama de rede

Primeiro,adicioneiasduastabelasderoteamento:

gateway:~#cat/etc/iproute2/rt_tables1ISP2VPN

Scriptsderoteamento

Regrasquesãoadicionadasquandooppp0sobenainicialização.Notequeestouusandoosganchosdopppdparamanterascoisasgenéricas link

gateway:~# cat /etc/ppp/ip-up 
#!/bin/sh
#
# This script is run by pppd when there's a successful ppp connection.
#

# Flush out any old routes when ppp0 goes down
/sbin/ip route flush table ISP

# Add a route for this subnet to the ISP table
/sbin/ip route add 192.168.1.0/24 dev eth0 table ISP prio 1

# Add a route from the ISP table
/sbin/ip rule add from ${IPLOCAL} table ISP prio 1

# Set default route to ppp0
/sbin/ip route add table ISP default via ${IPLOCAL} prio 1

Regras adicionadas quando a VPN é ativada. O OpenVPN também possui variáveis ambientais: link

# cat /etc/openvpn/route-up-fwmark.sh 
#!/bin/sh
#
# This script is run by OpenVPN when there's a successful VPN connection.
#

# Flush out any old routes when ppp0 goes down
/sbin/ip route flush table VPN

# Add a route for this subnet to the VPN table
/sbin/ip route add 192.168.2.0/24 dev eth0 table VPN prio 2

# Add a route from the VPN table
/sbin/ip rule add from ${route_vpn_gateway} table VPN prio 2

# Set default route to tun0
/sbin/ip route add default via ${route_vpn_gateway} dev ${dev} table VPN prio 2

Tabelas de roteamento

main:

gateway:~# ip route sh table main
default dev ppp0  scope link  metric 300
172.16.32.0/20 dev tun0  proto kernel  scope link  src 172.16.39.64
192.168.0.0/30 dev eth1  proto kernel  scope link  src 192.168.0.2
192.168.1.0/24 dev eth0  proto kernel  scope link  src 192.168.1.1
192.168.2.0/24 dev eth0  proto kernel  scope link  src 192.168.2.1
${IPREMOTE} dev ppp0  proto kernel  scope link  src ${IPLOCAL}

ISP:

gateway:~# ip route sh table ISP
default via ${IPLOCAL} dev ppp0
192.168.1.0/24 dev eth0  scope link

VPN:

gateway:~# ip route sh table VPN
default via 172.16.32.1 dev tun0
192.168.2.0/24 dev eth0  scope link

Regras de IP

Em / etc / network / interfaces, adicionei isso em uma das interfaces:

post-up /etc/network/fwmark_2_0_subnet_rules

que contém:

gateway:~#  cat /etc/network/fwmark_2_0_subnet_rules
#!/bin/sh

/sbin/ip rule add fwmark 1 table ISP prio 1
/sbin/ip rule add fwmark 2 table VPN prio 2

Finalmente, todas as regras de ip acima:

gateway:~# ip rule
0: from all lookup local
1: from all fwmark 0x1 lookup ISP
1: from <PPP IP ADDRESS> lookup ISP
2: from all fwmark 0x2 lookup VPN
2: from 172.16.32.1 lookup VPN
32766: from all lookup main
32767: from all lookup default

Regras do IPTables

#########################################################################
# Advanced routing rule set
# Uses 192.168.1.0 via ISP
#      192.168.2.0 via VPN
#
# Packets to/from 192.168.1.0/24 are marked with 0x1 and routed to ISP
# Packets to/from 192.168.2.0/24 are marked with 0x2 and routed to VPN
#
# http://nerdboys.com/2006/05/05/conning-the-mark-multiwan-connections-using-iptables-mark-connmark-and-iproute2/
# http://nerdboys.com/2006/05/08/multiwan-connections-addendum/
#########################################################################

# Set up the mangle table
*mangle
:PREROUTING ACCEPT [0:0]
:INPUT ACCEPT [0:0]
:FORWARD ACCEPT [0:0]
:OUTPUT ACCEPT [0:0]
:POSTROUTING ACCEPT [0:0]

# Restore CONNMARK to the MARK (If one doesn't exist then no mark is set
-A PREROUTING -j CONNMARK --restore-mark --nfmask 0xffffffff --ctmask 0xffffffff

# If packet MARK is 2, then it means there is already a connection mark and the original packet came in on VPN
-A PREROUTING -s 192.168.2.0/24 -m mark --mark 0x2 -j ACCEPT

# Else MARK packet as 2
#-A PREROUTING -i tun0 -j MARK --set-xmark 0x2/0xffffffff
-A PREROUTING -i tun0 -m conntrack --ctstate NEW -m mark --mark 0x0 -j MARK --set-xmark 0x2/0xffffffff

# If packet MARK is 1, then it means there is already a connection mark and the original packet came in on ISP
-A PREROUTING -s 192.168.1.0/24 -m mark --mark 0x1 -j ACCEPT

# Else MARK packet as 1
#-A PREROUTING -i ppp0 -j MARK --set-xmark 0x1/0xffffffff
-A PREROUTING -i ppp0 -m conntrack --ctstate NEW -m mark --mark 0x0 -j MARK --set-xmark 0x1/0xffffffff

# Save MARK to CONNMARK
-A PREROUTING -j CONNMARK --save-mark --nfmask 0xffffffff --ctmask 0xffffffff
COMMIT

# Set up the filter table
*filter
:INPUT DROP [0:0]
:FORWARD DROP [0:0]
:OUTPUT ACCEPT [0:0]

# Create rule chain per input interface for forwarding packets
:FWD_ETH0 - [0:0]
:FWD_ETH1 - [0:0]
:FWD_PPP0 - [0:0]
:FWD_TUN0 - [0:0]

# Create rule chain per input interface for input packets (for host itself)
:IN_ETH0 - [0:0]
:IN_ETH1 - [0:0]
:IN_PPP0 - [0:0]
:IN_TUN0 - [0:0]

# Pass input packet to corresponded rule chain
-A INPUT -i lo -j ACCEPT
-A INPUT -i eth0 -j IN_ETH0
-A INPUT -i eth1 -j IN_ETH1
-A INPUT -i ppp0 -j IN_PPP0
-A INPUT -i tun0 -j IN_TUN0

# TCP flag checks - block invalid flags
-A INPUT -m conntrack --ctstate INVALID -j DROP

# Log packets that are dropped in INPUT chain (useful for debugging)
-A INPUT -j LOG --log-prefix "iptables/filter/INPUT end"

# Pass forwarded packet to corresponded rule chain
-A FORWARD -i eth0 -j FWD_ETH0
-A FORWARD -i eth1 -j FWD_ETH1
-A FORWARD -i ppp0 -j FWD_PPP0
-A FORWARD -i tun0 -j FWD_TUN0

# Log packets that are dropped in FORWARD chain (useful for debugging)
-A FORWARD -j LOG --log-prefix "iptables/filter/FORWARD end"

# Forward traffic to LAN
-A FWD_ETH0 -s 192.168.1.0/24 -m conntrack --ctstate NEW,ESTABLISHED -j ACCEPT

# Forward traffic to VPN
-A FWD_ETH0 -s 192.168.2.0/24 -m conntrack --ctstate NEW,ESTABLISHED -j ACCEPT

# Forward SSH packets from network to modem
-A FWD_ETH1 -s 192.168.0.0/30 -d 192.168.1.0/24 -p tcp -m tcp --sport 22 -m conntrack --ctstate NEW,ESTABLISHED -j ACCEPT
-A FWD_ETH1 -s 192.168.0.0/30 -d 192.168.2.0/24 -p tcp -m tcp --sport 22 -m conntrack --ctstate NEW,ESTABLISHED -j ACCEPT

# Forward traffic to ppp0 WAN port
-A FWD_PPP0 -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT

# Forward ICMP from VPN, (breaks traceroute through VPN if you don't have this)
-A FWD_TUN0 -d 192.168.2.0/24 -p icmp -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT

# Forward traffic to tun0 VPN port
-A FWD_TUN0 -d 192.168.2.0/24 -m conntrack --ctstate NEW,ESTABLISHED -j ACCEPT

# SSH to Router
-A IN_ETH0 -s 192.168.1.0/24 -p tcp -m tcp --dport 22 -m conntrack --ctstate NEW,ESTABLISHED -j ACCEPT
-A IN_ETH0 -s 192.168.2.0/24 -p tcp -m tcp --dport 22 -m conntrack --ctstate NEW,ESTABLISHED -j ACCEPT

# DNS to Router
-A IN_ETH0 -s 192.168.1.0/24 -p udp -m udp --dport 53 -m conntrack --ctstate NEW -j ACCEPT
-A IN_ETH0 -s 192.168.2.0/24 -p udp -m udp --dport 53 -m conntrack --ctstate NEW -j ACCEPT

# FreeRadius Client
-A IN_ETH0 -s 192.168.1.0/24 -p tcp -m tcp --dport 1812 -m conntrack --ctstate NEW,ESTABLISHED -j ACCEPT
-A IN_ETH0 -s 192.168.1.0/24 -p udp -m udp --dport 1812 -m conntrack --ctstate NEW,ESTABLISHED -j ACCEPT

# Ubiquiti UAP Device Discovery Broadcast
-A IN_ETH0 -s 192.168.1.0/24 -p udp -m udp --dport 10001 -m conntrack --ctstate NEW,ESTABLISHED -j ACCEPT

# NTP
-A IN_ETH0 -s 192.168.1.0/24 -p udp -m udp --dport 123 -m conntrack --ctstate NEW,ESTABLISHED -j ACCEPT
-A IN_ETH0 -s 192.168.2.0/24 -p udp -m udp --dport 123 -m conntrack --ctstate NEW,ESTABLISHED -j ACCEPT

# Accept traffic to router on both subnets
-A IN_ETH0 -s 192.168.1.0/24 -m conntrack --ctstate NEW,ESTABLISHED -j ACCEPT
-A IN_ETH0 -s 192.168.2.0/24 -m conntrack --ctstate NEW,ESTABLISHED -j ACCEPT

# Prevent leakages from 192.168.2.0/24 hosts when VPN goes down for some reason
-A IN_ETH0 -s 192.168.2.0/24 -o ppp0 -j REJECT --reject-with icmp-port-unreachable

# SSH To Modem from Router
-A IN_ETH1 -s 192.168.0.0/30 -d 192.168.0.0/30 -p tcp -m tcp --sport 22 -m conntrack --ctstate NEW,ESTABLISHED -j ACCEPT

# Accept incoming tracked PPP0 connections
-A IN_PPP0 -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT

# Incoming ICMP from VPN, (breaks traceroute through VPN if you don't have this)
-A IN_TUN0 -d 192.168.2.0/24 -p icmp -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT

# Accept incoming tracked connections from 192.168.2.0/24 to VPN
-A IN_TUN0 -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT
COMMIT

*nat
:PREROUTING ACCEPT [0:0]
:INPUT ACCEPT [0:0]
:OUTPUT ACCEPT [0:0]
:POSTROUTING ACCEPT [0:0]

# Bittorrent forwarded to Linux Workstation through VPN
-A PREROUTING -i tun0 -p tcp -m tcp --dport 6881:6889 -j DNAT --to-destination 192.168.2.20
-A PREROUTING -i tun0 -p udp -m udp --dport 6881:6889 -j DNAT --to-destination 192.168.2.20

# Allows for network hosts to access the internet via VPN tunnel
-A POSTROUTING -s 192.168.2.0/24 -o tun0 -j MASQUERADE

# Allows for network hosts to access the internet via WAN port
-A POSTROUTING -s 192.168.1.0/24 -o ppp0 -j MASQUERADE
COMMIT

Eu suspeito que o problema reside na minha tabela mangle. Parece que alguns dos pacotes estão sendo marcados:

gateway:~# iptables -L --line-numbers -n -v -t mangle
Chain PREROUTING (policy ACCEPT 1577 packets, 139K bytes)
num   pkts bytes target     prot opt in     out     source               destination
1     1577  139K CONNMARK   all  --  *      *       0.0.0.0/0            0.0.0.0/0            CONNMARK restore
2        0     0 ACCEPT     all  --  *      *       192.168.2.0/24       0.0.0.0/0            mark match 0x2
3        0     0 MARK       all  --  tun0   *       0.0.0.0/0            0.0.0.0/0            ctstate NEW mark match 0x0 MARK set 0x2
4        0     0 ACCEPT     all  --  *      *       192.168.1.0/24       0.0.0.0/0            mark match 0x1
5      112  6720 MARK       all  --  ppp0   *       0.0.0.0/0            0.0.0.0/0            ctstate NEW mark match 0x0 MARK set 0x1
6     1577  139K CONNMARK   all  --  *      *       0.0.0.0/0            0.0.0.0/0            CONNMARK save

Chain INPUT (policy ACCEPT 758 packets, 68909 bytes)
num   pkts bytes target     prot opt in     out     source               destination

Chain FORWARD (policy ACCEPT 819 packets, 69715 bytes)
num   pkts bytes target     prot opt in     out     source               destination

Chain OUTPUT (policy ACCEPT 620 packets, 99208 bytes)
num   pkts bytes target     prot opt in     out     source               destination

Chain POSTROUTING (policy ACCEPT 1380 packets, 166K bytes)
num   pkts bytes target     prot opt in     out     source               destination

Quaisquer outras melhorias bem-vindas, planejo atualizar o artigo wiki do AlpineLinux com as alterações.

networking openvpn iptables routing router

por moonmoon 03.08.2015 / 18:54

1 resposta

Tags networking openvpn iptables routing router

FFplay - Procura o quadro chave anterior O que está causando uma pasta para agir oculta quando não é?

score 0 · Accepted Answer

Eu finalmente descobri uma solução para esta.

Primeiro, como na edição anterior, edite e adicione a / etc / iproute2 / rt_tables

1 ISP
2 VPN

Em seguida, adicione a / etc / network / interfaces

auto eth0:2
iface eth0:2 inet static
    address 192.168.2.1
    netmask 255.255.255.0
    post-up /etc/network/fwmark_rules

Crie o arquivo / etc / network / fwmark_rules aqui nós eliminamos as regras do fwmark:

#!/bin/sh

# Normal packets to go direct out WAN
/sbin/ip rule add fwmark 1 table ISP prio 100

# Put packets destined into VPN when VPN is up
/sbin/ip rule add fwmark 2 table VPN prio 200

# Prevent packets from being routed out when VPN is down.
# This prevents packets from falling back to the main table
# that has a priority of 32766
/sbin/ip rule add prohibit fwmark 2 prio 300

A linha proibir impede que as coisas na VPN da tabela voltem ao principal se a VPN cair, pois sua prioridade é menor que 32766. Você pode ler sobre proibir e outras regras especiais em 4.9. Banco de dados de diretivas de roteamento (RPDB)

Adicione / etc / ppp / ip-up . É aqui que colocamos as regras de ip para quando a conexão PPP ficar online.

#!/bin/sh
#
# This script is run by pppd when there's a successful ppp connection.
#

# Flush out any old rules that might be there
/sbin/ip route flush table ISP

# Add route to table from subnets on LAN
/sbin/ip route add 192.168.1.0/24 dev eth0 table ISP prio 100
/sbin/ip route add 192.168.2.0/24 dev eth0 table ISP prio 200

# Add route from IP given by ISP to the table
/sbin/ip rule add from ${IPLOCAL} table ISP prio 100

# Add a default route
/sbin/ip route add table ISP default via ${IPLOCAL} prio 100

Assegure-se de adicionar / etc / ppp / ip-down . É aqui que excluímos a regra quando a interface é desativada, para que não tenhamos duplicatas. Você pode ler sobre os valores especiais do gancho no arquivo pppd man - Scripts

#!/bin/sh
#
# This script is run by pppd after the connection has ended.
#

# Delete the rules when we take the interface down
/sbin/ip rule del from ${IPLOCAL} table ISP prio 100

Agora precisamos criar os scripts de roteamento para o OpenVPN. Então edite /etc/openvpn/route-up-fwmark.sh O OpenVPN também tem variáveis ambientais especiais OpenVPN - Variáveis Ambientais)

#!/bin/sh
#
# This script is run by OpenVPN when there's a successful VPN connection.
#

# Flush out any old rules that might be there
/sbin/ip route flush table VPN

# Add route to table from 192.168.2.0/24 subnet on LAN
/sbin/ip route add 192.168.2.0/24 dev eth0 table VPN prio 200

# Add route from VPN interface IP to the VPN table
/sbin/ip rule add from ${ifconfig_local} table VPN prio 200

# Add a default route
/sbin/ip route add default via ${ifconfig_local} dev ${dev} table VPN prio 200

E para excluir a regra antes que a interface seja desativada /etc/openvpn/route-pre-down-fwmark.sh

#!/bin/sh
#
# This script is run by OpenVPN after the connection has ended
#

# Delete the rules when we take the interface down
/sbin/ip rule del from ${ifconfig_local} table VPN prio 200

Por fim, sua tabela de mangle deve ficar assim:

*mangle

# Set default policies for table
:PREROUTING ACCEPT [0:0]
:INPUT ACCEPT [0:0]
:FORWARD ACCEPT [0:0]
:OUTPUT ACCEPT [0:0]
:POSTROUTING ACCEPT [0:0]

# Restore CONNMARK to the MARK (If one doesn't exist then no mark is set)
-A PREROUTING -j CONNMARK --restore-mark --nfmask 0xffffffff --ctmask 0xffffffff

# If packet MARK is 2, then it means there is already a connection mark and the original packet came in on VPN
-A PREROUTING -s 192.168.2.0/24 -m mark --mark 0x2 -j ACCEPT

# Check exception (this is a server which when accessed on a 192.168.2.0/24 address will go out the ISP table) are 0x1
#-A PREROUTING -s 192.168.2.0/24 -d <IP_OF_EXCEPTED_SERVER>/32 -m mark --mark 0x1 -j ACCEPT

# Check packets coming from 192.168.2.0/24 are 0x2
-A PREROUTING -s 192.168.2.0/24 -j MARK --set-xmark 0x2/0xffffffff

# If packet MARK is 1, then it means there is already a connection mark and the original packet came in on ISP
-A PREROUTING -s 192.168.1.0/24 -m mark --mark 0x1 -j ACCEPT

# Check packets coming from 192.168.1.0/24 are 0x1
-A PREROUTING -s 192.168.1.0/24 -j MARK --set-xmark 0x1/0xffffffff

# Mark exception (this is a server which when accessed on a 192.168.2.0/24 address will go out the ISP table) as 0x1
#-A PREROUTING -s 192.168.2.0/24 -d <IP_OF_EXCEPTED_SERVER>/32 -j MARK --set-xmark 0x1/0xffffffff

# Save MARK to CONNMARK (remember iproute can't see CONNMARKs)
-A PREROUTING -j CONNMARK --save-mark --nfmask 0xffffffff --ctmask 0xffffffff
COMMIT

Você também vai querer editar o /etc/openvpn/openvpn.conf e adicionar

# Prevents default gateway from being set on the default routing table
route-noexec

# Allows route-up script to be executed
script-security 2

# Calls custom shell script after connection to add necessary routes
route-up /etc/openvpn/route-up-fwmark.sh
route-pre-down /etc/openvpn/route-pre-down-fwmark.sh