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net/nat: Add UDP support

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Signed-off-by: Zhe Weng <wengzhe@xiaomi.com>
This commit is contained in:
Zhe Weng 2022-11-03 14:26:21 +08:00 committed by Xiang Xiao
parent 8d401db5b9
commit a3a669a5f6
4 changed files with 171 additions and 6 deletions
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11
net/nat/Kconfig
View File

@ -20,6 +20,17 @@ config NET_NAT_TCP_EXPIRE_SEC
Note: The default value 86400 is suggested by RFC2663, Section 2.6,
Page 5.
config NET_NAT_UDP_EXPIRE_SEC
int "UDP NAT entry expiration seconds"
default 240
depends on NET_NAT
---help---
The expiration time for idle UDP entry in NAT.
Note: RFC2663 (Section 2.6, Page 5) suggests that non-TCP sessions
that have not been used for a couple of minutes can be assumed to be
terminated.
config NET_NAT_ICMP_EXPIRE_SEC
int "ICMP NAT entry expiration seconds"
default 60

126
net/nat/ipv4_nat.c
View File

@ -31,6 +31,7 @@
#include <nuttx/net/icmp.h>
#include <nuttx/net/tcp.h>
#include <nuttx/net/udp.h>
#include "nat/nat.h"
#include "utils/utils.h"
@ -103,6 +104,65 @@ static int ipv4_nat_inbound_tcp(FAR struct ipv4_hdr_s *ipv4)
}
#endif
/****************************************************************************
* Name: ipv4_nat_inbound_udp
*
* Description:
* Check if a received UDP packet belongs to a NAT entry. If so, translate
* it.
*
* Input Parameters:
* ipv4 - Points to the IPv4 header with dev->d_buf.
*
* Returned Value:
* Zero is returned if NAT is successfully applied, or is not enabled for
* this packet;
* A negated errno value is returned if error occured.
*
* Assumptions:
* Packet is received on NAT device and is targeting at the address
* assigned to the device.
*
****************************************************************************/
#ifdef CONFIG_NET_UDP
static int ipv4_nat_inbound_udp(FAR struct ipv4_hdr_s *ipv4)
{
uint16_t iphdrlen = (ipv4->vhl & IPv4_HLMASK) << 2;
FAR struct udp_hdr_s *udp =
(FAR struct udp_hdr_s *)((FAR uint8_t *)ipv4 + iphdrlen);
FAR struct ipv4_nat_entry *entry =
ipv4_nat_inbound_entry_find(IP_PROTO_UDP, udp->destport, true);
if (!entry)
{
/* Inbound without entry is OK (e.g. towards NuttX itself), skip NAT. */
return OK;
}
/* Modify port and checksum. */
if (udp->udpchksum != 0) /* UDP checksum has special case 0 (no checksum) */
{
chksum_adjust(udp->udpchksum, udp->destport, entry->local_port);
}
udp->destport = entry->local_port;
/* Modify address and checksum. */
if (udp->udpchksum != 0) /* UDP checksum has special case 0 (no checksum) */
{
chksum_adjust(udp->udpchksum, ipv4->destipaddr, entry->local_ip);
}
chksum_adjust(ipv4->ipchksum, ipv4->destipaddr, entry->local_ip);
net_ipv4addr_hdrcopy(ipv4->destipaddr, &entry->local_ip);
return OK;
}
#endif
/****************************************************************************
* Name: ipv4_nat_inbound_icmp
*
@ -213,6 +273,66 @@ static int ipv4_nat_outbound_tcp(FAR struct net_driver_s *dev,
}
#endif
/****************************************************************************
* Name: ipv4_nat_outbound_udp
*
* Description:
* Check if we want to perform NAT with this outbound UDP packet before
* sending it. If so, translate it.
*
* Input Parameters:
* dev - The device to sent the packet.
* ipv4 - Points to the IPv4 header to be filled into dev->d_buf later.
*
* Returned Value:
* Zero is returned if NAT is successfully applied, or is not enabled for
* this packet;
* A negated errno value is returned if error occured.
*
* Assumptions:
* Packet will be sent on NAT device.
*
****************************************************************************/
#ifdef CONFIG_NET_UDP
static int ipv4_nat_outbound_udp(FAR struct net_driver_s *dev,
FAR struct ipv4_hdr_s *ipv4)
{
uint16_t iphdrlen = (ipv4->vhl & IPv4_HLMASK) << 2;
FAR struct udp_hdr_s *udp =
(FAR struct udp_hdr_s *)((FAR uint8_t *)ipv4 + iphdrlen);
FAR struct ipv4_nat_entry *entry = ipv4_nat_outbound_entry_find(
dev, IP_PROTO_UDP, net_ip4addr_conv32(ipv4->srcipaddr), udp->srcport);
if (!entry)
{
/* Outbound entry creation failed, should have corresponding entry. */
return -ENOMEM;
}
/* Modify port and checksum. */
if (udp->udpchksum != 0) /* UDP checksum has special case 0 (no checksum) */
{
chksum_adjust(udp->udpchksum, udp->srcport, entry->external_port);
}
udp->srcport = entry->external_port;
/* Modify address and checksum. */
if (udp->udpchksum != 0) /* UDP checksum has special case 0 (no checksum) */
{
chksum_adjust(udp->udpchksum, ipv4->srcipaddr, dev->d_ipaddr);
}
chksum_adjust(ipv4->ipchksum, ipv4->srcipaddr, dev->d_ipaddr);
net_ipv4addr_hdrcopy(ipv4->srcipaddr, &dev->d_ipaddr);
return OK;
}
#endif
/****************************************************************************
* Name: ipv4_nat_outbound_icmp
*
@ -379,7 +499,8 @@ int ipv4_nat_inbound(FAR struct net_driver_s *dev,
#endif
#ifdef CONFIG_NET_UDP
# warning Missing logic
case IP_PROTO_UDP:
return ipv4_nat_inbound_udp(ipv4);
#endif
#ifdef CONFIG_NET_ICMP
@ -430,7 +551,8 @@ int ipv4_nat_outbound(FAR struct net_driver_s *dev,
#endif
#ifdef CONFIG_NET_UDP
# warning Missing logic
case IP_PROTO_UDP:
return ipv4_nat_outbound_udp(dev, ipv4);
#endif
#ifdef CONFIG_NET_ICMP

23
net/nat/ipv4_nat_entry.c
View File

@ -33,6 +33,7 @@
#include "icmp/icmp.h"
#include "nat/nat.h"
#include "tcp/tcp.h"
#include "udp/udp.h"
#if defined(CONFIG_NET_NAT) && defined(CONFIG_NET_IPv4)
@ -145,7 +146,22 @@ static uint16_t ipv4_nat_select_port(FAR struct net_driver_s *dev,
#endif
#ifdef CONFIG_NET_UDP
# warning Missing logic
case IP_PROTO_UDP:
{
#ifndef CONFIG_NET_UDP_NO_STACK
union ip_binding_u u;
u.ipv4.laddr = dev->d_draddr;
u.ipv4.raddr = INADDR_ANY;
/* TODO: Try keep origin port as possible. */
return HTONS(udp_select_port(PF_INET, &u));
#else
return ipv4_nat_select_port_without_stack(IP_PROTO_UDP,
dev->d_draddr,
local_port);
#endif
}
#endif
#ifdef CONFIG_NET_ICMP
@ -212,7 +228,10 @@ static void ipv4_nat_entry_refresh(FAR struct ipv4_nat_entry *entry)
#endif
#ifdef CONFIG_NET_UDP
# warning Missing logic
case IP_PROTO_UDP:
entry->expire_time = TICK2SEC(clock_systime_ticks()) +
CONFIG_NET_NAT_UDP_EXPIRE_SEC;
break;
#endif
#ifdef CONFIG_NET_ICMP

17
net/udp/udp_conn.c
View File

@ -64,6 +64,7 @@
#include <nuttx/net/udp.h>
#include "devif/devif.h"
#include "nat/nat.h"
#include "netdev/netdev.h"
#include "inet/inet.h"
#include "udp/udp.h"
@ -533,7 +534,13 @@ uint16_t udp_select_port(uint8_t domain, FAR union ip_binding_u *u)
g_last_udp_port = 4096;
}
}
while (udp_find_conn(domain, u, HTONS(g_last_udp_port)) != NULL);
while (udp_find_conn(domain, u, HTONS(g_last_udp_port)) != NULL
#if defined(CONFIG_NET_NAT) && defined(CONFIG_NET_IPv4)
|| (domain == PF_INET &&
ipv4_nat_port_inuse(IP_PROTO_UDP, u->ipv4.laddr,
HTONS(g_last_udp_port)))
#endif
);
/* Initialize and return the connection structure, bind it to the
* port number
@ -816,7 +823,13 @@ int udp_bind(FAR struct udp_conn_s *conn, FAR const struct sockaddr *addr)
* and port ?
*/
if (udp_find_conn(conn->domain, &conn->u, portno) == NULL)
if (udp_find_conn(conn->domain, &conn->u, portno) == NULL
#if defined(CONFIG_NET_NAT) && defined(CONFIG_NET_IPv4)
&& !(conn->domain == PF_INET &&
ipv4_nat_port_inuse(IP_PROTO_UDP, conn->u.ipv4.laddr,
portno))
#endif
)
{
/* No.. then bind the socket to the port */