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net/ipfwd: Support ICMP error reply when forwarding IPv4

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Signed-off-by: Zhe Weng <wengzhe@xiaomi.com>
This commit is contained in:
Zhe Weng 2022-11-14 16:50:21 +08:00 committed by Xiang Xiao
parent da6ab79d65
commit f416fd86bb
3 changed files with 68 additions and 26 deletions
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57
net/ipforward/ipv4_forward.c
View File

@ -37,6 +37,7 @@
#include "netdev/netdev.h"
#include "utils/utils.h"
#include "sixlowpan/sixlowpan.h"
#include "icmp/icmp.h"
#include "ipforward/ipforward.h"
#include "nat/nat.h"
#include "devif/devif.h"
@ -148,12 +149,6 @@ static int ipv4_decr_ttl(FAR struct ipv4_hdr_s *ipv4)
ttl = (int)ipv4->ttl - 1;
if (ttl <= 0)
{
#ifdef CONFIG_NET_ICMP
/* Return an ICMP error packet back to the sender. */
# warning Missing logic
#endif
/* Return zero which must cause the packet to be dropped */
return 0;
@ -317,7 +312,8 @@ static int ipv4_dev_forward(FAR struct net_driver_s *dev,
/* Try NAT outbound, rule matching will be performed in NAT module. */
ret = ipv4_nat_outbound(fwd->f_dev,
(FAR struct ipv4_hdr_s *)fwd->f_iob->io_data);
(FAR struct ipv4_hdr_s *)fwd->f_iob->io_data,
NAT_MANIP_SRC);
if (ret < 0)
{
nwarn("WARNING: Performing NAT outbound failed, dropping!\n");
@ -444,6 +440,10 @@ int ipv4_forward(FAR struct net_driver_s *dev, FAR struct ipv4_hdr_s *ipv4)
in_addr_t srcipaddr;
FAR struct net_driver_s *fwddev;
int ret;
#ifdef CONFIG_NET_ICMP
int icmp_reply_type;
int icmp_reply_code;
#endif /* CONFIG_NET_ICMP */
/* Search for a device that can forward this packet. */
@ -454,7 +454,8 @@ int ipv4_forward(FAR struct net_driver_s *dev, FAR struct ipv4_hdr_s *ipv4)
if (fwddev == NULL)
{
nwarn("WARNING: Not routable\n");
return (ssize_t)-ENETUNREACH;
ret = -ENETUNREACH;
goto drop;
}
/* Check if we are forwarding on the same device that we received the
@ -505,8 +506,48 @@ int ipv4_forward(FAR struct net_driver_s *dev, FAR struct ipv4_hdr_s *ipv4)
drop:
ipv4_dropstats(ipv4);
#ifdef CONFIG_NET_ICMP
/* Reply ICMP to the sender for particular errors. */
switch (ret)
{
case -ENETUNREACH:
icmp_reply_type = ICMP_DEST_UNREACHABLE;
icmp_reply_code = ICMP_NET_UNREACH;
goto reply;
case -EFBIG:
icmp_reply_type = ICMP_DEST_UNREACHABLE;
icmp_reply_code = ICMP_FRAG_NEEDED;
goto reply;
case -EMULTIHOP:
icmp_reply_type = ICMP_TIME_EXCEEDED;
icmp_reply_code = 0;
goto reply;
default:
break; /* We don't know how to reply, just go on (to drop). */
}
#endif /* CONFIG_NET_ICMP */
dev->d_len = 0;
return ret;
#ifdef CONFIG_NET_ICMP
reply:
# ifdef CONFIG_NET_NAT
/* Before we reply ICMP, call NAT outbound to try to translate destination
* address & port back to original status.
*/
ipv4_nat_outbound(dev, ipv4, NAT_MANIP_DST);
# endif /* CONFIG_NET_NAT */
icmp_reply(dev, icmp_reply_type, icmp_reply_code);
return OK;
#endif /* CONFIG_NET_ICMP */
}
/****************************************************************************

23
net/nat/ipv4_nat.c
View File

@ -76,20 +76,6 @@
# define L4_MAXHDRLEN ICMP_HDRLEN
#endif
/****************************************************************************
* Private Types
****************************************************************************/
/* NAT IP/Port manipulate type, to indicate whether to manipulate source or
* destination IP/Port in a packet.
*/
enum nat_manip_type_e
{
NAT_MANIP_SRC,
NAT_MANIP_DST
};
/****************************************************************************
* Private Function Prototypes
****************************************************************************/
@ -790,6 +776,7 @@ int ipv4_nat_inbound(FAR struct net_driver_s *dev,
* Input Parameters:
* dev - The device on which the packet will be sent.
* ipv4 - Points to the IPv4 header to be filled into dev->d_buf later.
* manip_type - Whether local IP/Port is in source or destination.
*
* Returned Value:
* Zero is returned if NAT is successfully applied, or is not enabled for
@ -799,20 +786,22 @@ int ipv4_nat_inbound(FAR struct net_driver_s *dev,
****************************************************************************/
int ipv4_nat_outbound(FAR struct net_driver_s *dev,
FAR struct ipv4_hdr_s *ipv4)
FAR struct ipv4_hdr_s *ipv4,
enum nat_manip_type_e manip_type)
{
/* We only process packets targeting at NAT device but not targeting at the
* address assigned to the device.
*/
if (IFF_IS_NAT(dev->d_flags) &&
!net_ipv4addr_hdrcmp(ipv4->srcipaddr, &dev->d_ipaddr) &&
!net_ipv4addr_hdrcmp(ipv4->destipaddr, &dev->d_ipaddr))
{
/* TODO: Skip broadcast? */
FAR struct ipv4_nat_entry *entry =
ipv4_nat_outbound_internal(dev, ipv4, NAT_MANIP_SRC);
if (!entry)
ipv4_nat_outbound_internal(dev, ipv4, manip_type);
if (manip_type == NAT_MANIP_SRC && !entry)
{
/* Outbound entry creation failed, should have entry. */

14
net/nat/nat.h
View File

@ -71,6 +71,16 @@ struct ipv4_nat_entry
uint32_t expire_time; /* The expiration time of this entry. */
};
/* NAT IP/Port manipulate type, to indicate whether to manipulate source or
* destination IP/Port in a packet.
*/
enum nat_manip_type_e
{
NAT_MANIP_SRC,
NAT_MANIP_DST
};
/****************************************************************************
* Public Function Prototypes
****************************************************************************/
@ -147,6 +157,7 @@ int ipv4_nat_inbound(FAR struct net_driver_s *dev,
* Input Parameters:
* dev - The device on which the packet will be sent.
* ipv4 - Points to the IPv4 header to be filled into dev->d_buf later.
* manip_type - Whether local IP/Port is in source or destination.
*
* Returned Value:
* Zero is returned if NAT is successfully applied, or is not enabled for
@ -156,7 +167,8 @@ int ipv4_nat_inbound(FAR struct net_driver_s *dev,
****************************************************************************/
int ipv4_nat_outbound(FAR struct net_driver_s *dev,
FAR struct ipv4_hdr_s *ipv4);
FAR struct ipv4_hdr_s *ipv4,
enum nat_manip_type_e manip_type);
/****************************************************************************
* Name: ipv4_nat_port_inuse