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rt-thread-stm32f072/rt-thread/components/net/lwip-nat/ipv4_nat.c

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feat: 适配rt-thread
2022-10-30 15:41:02 +08:00
/**
* NAT - NAT implementation for lwIP supporting TCP/UDP and ICMP.
* Copyright (c) 2009 Christian Walter, ?Embedded Solutions, Vienna 2009.
* Copyright (c) 2010 lwIP project ;-)
* COPYRIGHT (C) 2015, RT-Thread Development Team
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without modification,
* are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
* SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
* OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
* IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
* OF SUCH DAMAGE.
*
* Change Logs:
* Date Author Notes
* 2015-01-26 Hichard porting to RT-Thread
* 2015-01-27 Bernard code cleanup for lwIP in RT-Thread
*/
/*
* TODOS:
* - we should decide if we want to use static tables for NAT or a linked
* list.
* - we should allocate icmp ping id if multiple clients are sending
* ping requests.
* - maybe we could hash the identifiers for TCP, ICMP and UDP and use
* a single table structure. This would reduce the code amount although
* it will cost performance.
* - NAT code must check for broadcast addresses and NOT forward
* them.
*
* - netif_remove must notify NAT code when a NAT'ed interface is removed
* - allocate NAT entries from a new memp pool instead of the heap
* - let ttl be ticks, not seconds
*
* HOWTO USE:
*
* Shows how to create NAT between a PPP interface and an internal NIC.
* In this case the network 213.129.231.168/29 is nat'ed when packets
* are sent to the destination network 10.0.0.0/24 (untypical example -
* most users will have the other way around).
*
* Step 1) Execute when network interfaces are ready.
*
* new_nat_entry.out_if = (struct netif *)&PPP_IF;
* new_nat_entry.in_if = (struct netif *)&EMAC_if;
* IP4_ADDR(&new_nat_entry.source_net, 213, 129, 231, 168);
* IP4_ADDR(&new_nat_entry.source_netmask, 255, 255, 255, 248);
* IP4_ADDR(&new_nat_entry.dest_net, 10, 0, 0, 0);
* IP4_ADDR(&new_nat_entry.source_netmask, 255, 0, 0, 0);
* ip_nat_add(&new_nat_entry);
*/
#include "ipv4_nat.h"
#include "lwip/opt.h"
#ifdef LWIP_USING_NAT
#include "lwip/ip.h"
#include "lwip/inet.h"
#include "lwip/netif.h"
#include "lwip/ip_addr.h"
#include "lwip/icmp.h"
#include "lwip/tcp_impl.h"
#include "lwip/udp.h"
#include "lwip/mem.h"
#include "lwip/sys.h"
#include "lwip/timers.h"
#include "netif/etharp.h"
#include <limits.h>
#include <string.h>
/** Define this to enable debug output of this module */
#ifndef LWIP_NAT_DEBUG
#define LWIP_NAT_DEBUG LWIP_DBG_OFF
#endif
#define LWIP_NAT_TTL_INFINITE (INT_MAX)
#define LWIP_NAT_DEFAULT_TTL_SECONDS (128)
#define LWIP_NAT_FORWARD_HEADER_SIZE_MIN (sizeof(struct eth_hdr))
#define LWIP_NAT_DEFAULT_STATE_TABLES_ICMP (4)
#define LWIP_NAT_DEFAULT_STATE_TABLES_TCP (32)
#define LWIP_NAT_DEFAULT_STATE_TABLES_UDP (32)
#define LWIP_NAT_DEFAULT_TCP_SOURCE_PORT (40000)
#define LWIP_NAT_DEFAULT_UDP_SOURCE_PORT (40000)
#define IPNAT_ENTRY_RESET(x) do { \
(x)->ttl = 0; \
} while(0)
typedef struct ip_nat_conf
{
struct ip_nat_conf *next;
ip_nat_entry_t entry;
} ip_nat_conf_t;
typedef struct ip_nat_entry_common
{
s32_t ttl; /* @todo: do we really need this to be signed?? */
ip_addr_t source;
ip_addr_t dest;
ip_nat_conf_t *cfg;
} ip_nat_entry_common_t;
typedef struct ip_nat_entries_icmp
{
ip_nat_entry_common_t common;
u16_t id;
u16_t seqno;
} ip_nat_entries_icmp_t;
typedef struct ip_nat_entries_tcp
{
ip_nat_entry_common_t common;
u16_t nport;
u16_t sport;
u16_t dport;
} ip_nat_entries_tcp_t;
typedef struct ip_nat_entries_udp
{
ip_nat_entry_common_t common;
u16_t nport;
u16_t sport;
u16_t dport;
} ip_nat_entries_udp_t;
typedef union u_nat_entry
{
ip_nat_entry_common_t *cmn;
ip_nat_entries_tcp_t *tcp;
ip_nat_entries_icmp_t *icmp;
ip_nat_entries_udp_t *udp;
} nat_entry_t;
static ip_nat_conf_t *ip_nat_cfg = NULL;
static ip_nat_entries_icmp_t ip_nat_icmp_table[LWIP_NAT_DEFAULT_STATE_TABLES_ICMP];
static ip_nat_entries_tcp_t ip_nat_tcp_table[LWIP_NAT_DEFAULT_STATE_TABLES_TCP];
static ip_nat_entries_udp_t ip_nat_udp_table[LWIP_NAT_DEFAULT_STATE_TABLES_UDP];
/* ----------------------- Static functions (COMMON) --------------------*/
static void ip_nat_chksum_adjust(u8_t *chksum, const u8_t *optr, s16_t olen, const u8_t *nptr, s16_t nlen);
static void ip_nat_cmn_init(ip_nat_conf_t *nat_config, const struct ip_hdr *iphdr,
ip_nat_entry_common_t *nat_entry);
static ip_nat_conf_t *ip_nat_shallnat(const struct ip_hdr *iphdr);
static void ip_nat_reset_state(ip_nat_conf_t *cfg);
/* ----------------------- Static functions (DEBUG) ---------------------*/
#if defined(LWIP_DEBUG) && (LWIP_NAT_DEBUG & LWIP_DBG_ON)
static void ip_nat_dbg_dump(const char *msg, const struct ip_hdr *iphdr);
static void ip_nat_dbg_dump_ip(const ip_addr_t *addr);
static void ip_nat_dbg_dump_icmp_nat_entry(const char *msg, const ip_nat_entries_icmp_t *nat_entry);
static void ip_nat_dbg_dump_tcp_nat_entry(const char *msg, const ip_nat_entries_tcp_t *nat_entry);
static void ip_nat_dbg_dump_udp_nat_entry(const char *msg, const ip_nat_entries_udp_t *nat_entry);
static void ip_nat_dbg_dump_init(ip_nat_conf_t *ip_nat_cfg_new);
static void ip_nat_dbg_dump_remove(ip_nat_conf_t *cur);
#else /* defined(LWIP_DEBUG) && (LWIP_NAT_DEBUG & LWIP_DBG_ON) */
#define ip_nat_dbg_dump(msg, iphdr)
#define ip_nat_dbg_dump_ip(addr)
#define ip_nat_dbg_dump_icmp_nat_entry(msg, nat_entry)
#define ip_nat_dbg_dump_tcp_nat_entry(msg, nat_entry)
#define ip_nat_dbg_dump_udp_nat_entry(msg, nat_entry)
#define ip_nat_dbg_dump_init(ip_nat_cfg_new)
#define ip_nat_dbg_dump_remove(cur)
#endif /* defined(LWIP_DEBUG) && (LWIP_NAT_DEBUG & LWIP_DBG_ON) */
/* ----------------------- Static functions (TCP) -----------------------*/
static ip_nat_entries_tcp_t *ip_nat_tcp_lookup_incoming(const struct ip_hdr *iphdr, const struct tcp_hdr *tcphdr);
static ip_nat_entries_tcp_t *ip_nat_tcp_lookup_outgoing(ip_nat_conf_t *nat_config,
const struct ip_hdr *iphdr, const struct tcp_hdr *tcphdr,
u8_t allocate);
/* ----------------------- Static functions (UDP) -----------------------*/
static ip_nat_entries_udp_t *ip_nat_udp_lookup_incoming(const struct ip_hdr *iphdr, const struct udp_hdr *udphdr);
static ip_nat_entries_udp_t *ip_nat_udp_lookup_outgoing(ip_nat_conf_t *nat_config,
const struct ip_hdr *iphdr, const struct udp_hdr *udphdr,
u8_t allocate);
/**
* Timer callback function that calls ip_nat_tmr() and reschedules itself.
*
* @param arg unused argument
*/
static void
nat_timer(void *arg)
{
LWIP_UNUSED_ARG(arg);
LWIP_DEBUGF(TIMERS_DEBUG, ("tcpip: nat_timer()\n"));
ip_nat_tmr();
sys_timeout(LWIP_NAT_TMR_INTERVAL_SEC * 1000, nat_timer, NULL);
}
/** Initialize this module */
void
ip_nat_init(void)
{
int i;
extern void lwip_ip_input_set_hook(int (*hook)(struct pbuf *p, struct netif *inp));
/* @todo: this can be omitted since we trust static variables
to be initialized to zero */
for (i = 0; i < LWIP_NAT_DEFAULT_STATE_TABLES_ICMP; i++) {
IPNAT_ENTRY_RESET(&ip_nat_icmp_table[i].common);
}
for (i = 0; i < LWIP_NAT_DEFAULT_STATE_TABLES_TCP; i++) {
IPNAT_ENTRY_RESET(&ip_nat_tcp_table[i].common);
}
for (i = 0; i < LWIP_NAT_DEFAULT_STATE_TABLES_UDP; i++) {
IPNAT_ENTRY_RESET(&ip_nat_udp_table[i].common);
}
/* we must lock scheduler to protect following code */
rt_enter_critical();
/* add a lwip timer for NAT */
sys_timeout(LWIP_NAT_TMR_INTERVAL_SEC * 1000, nat_timer, NULL);
/* un-protect */
rt_exit_critical();
}
/** Allocate a new ip_nat_conf_t item */
static ip_nat_conf_t*
ip_nat_alloc(void)
{
ip_nat_conf_t *ret = (ip_nat_conf_t*)mem_malloc(sizeof(ip_nat_conf_t));
return ret;
}
/** Free a removed ip_nat_conf_t item */
static void
ip_nat_free(ip_nat_conf_t *item)
{
LWIP_ASSERT("item != NULL", item != NULL);
mem_free(item);
}
/** Add a new NAT entry
*
* @param new_entry pointer to a structure used to initialize the entry
* @return ERR_OK if succeeded
*/
err_t
ip_nat_add(const ip_nat_entry_t *new_entry)
{
err_t err = ERR_VAL;
ip_nat_conf_t *cur = ip_nat_cfg;
ip_nat_conf_t *ip_nat_cfg_new = ip_nat_alloc();
LWIP_ASSERT("new_entry != NULL", new_entry != NULL);
if (ip_nat_cfg_new != NULL) {
SMEMCPY(&ip_nat_cfg_new->entry, new_entry, sizeof(ip_nat_entry_t));
ip_nat_cfg_new->next = NULL;
ip_nat_dbg_dump_init(ip_nat_cfg_new);
if (ip_nat_cfg == NULL) {
ip_nat_cfg = ip_nat_cfg_new;
} else {
/* @todo: do we really need to enqueue the new entry at the end?? */
while (cur->next != NULL) {
cur = cur->next;
}
cur->next = ip_nat_cfg_new;
}
err = ERR_OK;
} else {
err = ERR_MEM;
}
return err;
}
/** Remove a NAT entry previously added by 'ip_nat_add()'.
*
* @param remove_entry describes the entry to remove
*/
void
ip_nat_remove(const ip_nat_entry_t *remove_entry)
{
ip_nat_conf_t *cur = ip_nat_cfg;
ip_nat_conf_t *next;
ip_nat_conf_t *previous = NULL;
while (cur != NULL) {
/* Remove the NAT interfaces */
if ((cur->entry.source_net.addr == remove_entry->source_net.addr) &&
(cur->entry.source_netmask.addr == remove_entry->source_netmask.addr) &&
(cur->entry.dest_net.addr == remove_entry->dest_net.addr) &&
(cur->entry.dest_netmask.addr == remove_entry->dest_netmask.addr) &&
(cur->entry.out_if == remove_entry->out_if) &&
(cur->entry.in_if == remove_entry->in_if))
{
ip_nat_dbg_dump_remove(cur);
ip_nat_reset_state(cur);
next = cur->next;
if (cur == ip_nat_cfg) {
ip_nat_cfg = next;
} else {
LWIP_ASSERT("NULL != previous", NULL != previous);
previous->next = next;
}
/* free 'cur' or there will be a memory leak */
ip_nat_free(cur);
return;
} else {
previous = cur;
cur = cur->next;
}
}
}
/** Reset a NAT configured entry to be reused.
* Effectively calls IPNAT_ENTRY_RESET() on 'cfg'.
*
* @param cfg NAT entry to reset
*/
static void
ip_nat_reset_state(ip_nat_conf_t *cfg)
{
int i;
/* @todo: optimize this!!!
why do we search for it anyway, if we have the pointer??? */
for (i = 0; i < LWIP_NAT_DEFAULT_STATE_TABLES_ICMP; i++) {
if(ip_nat_icmp_table[i].common.cfg == cfg) {
IPNAT_ENTRY_RESET(&ip_nat_icmp_table[i].common);
}
}
for (i = 0; i < LWIP_NAT_DEFAULT_STATE_TABLES_TCP; i++) {
if(ip_nat_tcp_table[i].common.cfg == cfg) {
IPNAT_ENTRY_RESET(&ip_nat_tcp_table[i].common);
}
}
for (i = 0; i < LWIP_NAT_DEFAULT_STATE_TABLES_UDP; i++) {
if(ip_nat_udp_table[i].common.cfg == cfg) {
IPNAT_ENTRY_RESET(&ip_nat_udp_table[i].common);
}
}
}
/** Check if this packet should be routed or should be translated
*
* @param iphdr the IP header to check
* @return - a NAT entry if the packet shall be translated,
* - NULL if the packet shall be routed normally
*/
static ip_nat_conf_t *
ip_nat_shallnat(const struct ip_hdr *iphdr)
{
ip_nat_conf_t *nat_config = ip_nat_cfg;
for (nat_config = ip_nat_cfg; nat_config != NULL; nat_config = nat_config->next) {
if (ip_addr_netcmp(&(iphdr->dest), &(nat_config->entry.dest_net),
&(nat_config->entry.dest_netmask)) ||
ip_addr_netcmp(&(iphdr->src), &(nat_config->entry.source_net),
&(nat_config->entry.source_netmask))) {
break;
}
}
return nat_config;
}
/** Check if the IP header can be hidden and if the remaining packet
* is long enough. p->payload is reset to the IP header on return.
*
* @param p received packet, p->payload pointing to IP header
* @param min_size minimum p->tot_len after hiding IP header
* @return a pointer to the next header (after IP header),
* NULL if hiding IP header fails or the packet is too short
*/
static void*
ip_nat_check_header(struct pbuf *p, u16_t min_size)
{
void *ret = NULL;
struct ip_hdr *iphdr = (struct ip_hdr*)p->payload;
s16_t iphdr_len = IPH_HL(iphdr) * 4;
if(!pbuf_header(p, -iphdr_len)) {
if(p->tot_len >= min_size) {
ret = p->payload;
}
/* Restore pbuf payload pointer from previous header check. */
pbuf_header(p, iphdr_len);
}
return ret;
}
/** Input processing: check if a received packet belongs to a NAT entry
* and if so, translated it and send it on.
*
* @param p received packet
* @return 1 if the packet has been consumed (it was a NAT packet),
* 0 if the packet has not been consumed (no NAT packet)
*/
u8_t
ip_nat_input(struct pbuf *p)
{
struct ip_hdr *iphdr = (struct ip_hdr*)p->payload;
struct tcp_hdr *tcphdr;
struct udp_hdr *udphdr;
struct icmp_echo_hdr *icmphdr;
nat_entry_t nat_entry;
err_t err;
u8_t consumed = 0;
int i;
struct pbuf *q = NULL;
nat_entry.cmn = NULL;
ip_nat_dbg_dump("ip_nat_in: checking nat for", iphdr);
switch (IPH_PROTO(iphdr)) {
case IP_PROTO_TCP:
tcphdr = (struct tcp_hdr*)ip_nat_check_header(p, sizeof(struct tcp_hdr));
if (tcphdr == NULL) {
LWIP_DEBUGF(LWIP_NAT_DEBUG, ("ip_nat_input: short tcp packet (%" U16_F " bytes) discarded\n", p->tot_len));
} else {
nat_entry.tcp = ip_nat_tcp_lookup_incoming(iphdr, tcphdr);
if (nat_entry.tcp != NULL) {
/* Refresh TCP entry */
nat_entry.tcp->common.ttl = LWIP_NAT_DEFAULT_TTL_SECONDS;
tcphdr->dest = nat_entry.tcp->sport;
/* Adjust TCP checksum for changed destination port */
ip_nat_chksum_adjust((u8_t *)&(tcphdr->chksum),
(u8_t *)&(nat_entry.tcp->nport), 2, (u8_t *)&(tcphdr->dest), 2);
/* Adjust TCP checksum for changing dest IP address */
ip_nat_chksum_adjust((u8_t *)&(tcphdr->chksum),
(u8_t *)&(nat_entry.cmn->cfg->entry.out_if->ip_addr.addr), 4,
(u8_t *)&(nat_entry.cmn->source.addr), 4);
consumed = 1;
}
}
break;
case IP_PROTO_UDP:
udphdr = (struct udp_hdr *)ip_nat_check_header(p, sizeof(struct udp_hdr));
if (udphdr == NULL) {
LWIP_DEBUGF(LWIP_NAT_DEBUG,
("ip_nat_input: short udp packet (%" U16_F " bytes) discarded\n",
p->tot_len));
} else {
nat_entry.udp = ip_nat_udp_lookup_incoming(iphdr, udphdr);
if (nat_entry.udp != NULL) {
/* Refresh UDP entry */
nat_entry.udp->common.ttl = LWIP_NAT_DEFAULT_TTL_SECONDS;
udphdr->dest = nat_entry.udp->sport;
/* Adjust UDP checksum for changed destination port */
ip_nat_chksum_adjust((u8_t *)&(udphdr->chksum),
(u8_t *)&(nat_entry.udp->nport), 2, (u8_t *)&(udphdr->dest), 2);
/* Adjust UDP checksum for changing dest IP address */
ip_nat_chksum_adjust((u8_t *)&(udphdr->chksum),
(u8_t *)&(nat_entry.cmn->cfg->entry.out_if->ip_addr.addr), 4,
(u8_t *)&(nat_entry.cmn->source.addr), 4);
consumed = 1;
}
}
break;
case IP_PROTO_ICMP:
icmphdr = (struct icmp_echo_hdr *)ip_nat_check_header(p, sizeof(struct icmp_echo_hdr));
if (icmphdr == NULL) {
LWIP_DEBUGF(LWIP_NAT_DEBUG,
("ip_nat_out: short icmp echo reply packet (%" U16_F " bytes) discarded\n",
p->tot_len));
} else {
if (ICMP_ER == ICMPH_TYPE(icmphdr)) {
for (i = 0; i < LWIP_NAT_DEFAULT_STATE_TABLES_ICMP; i++) {
nat_entry.icmp = &ip_nat_icmp_table[i];
if ((nat_entry.icmp->common.ttl) &&
(iphdr->src.addr == nat_entry.icmp->common.dest.addr) &&
(nat_entry.icmp->id == icmphdr->id) &&
(nat_entry.icmp->seqno == icmphdr->seqno)) {
ip_nat_dbg_dump_icmp_nat_entry("found existing nat entry: ", nat_entry.icmp);
consumed = 1;
IPNAT_ENTRY_RESET(nat_entry.cmn);
break;
}
}
}
}
break;
default:
break;
}
if(consumed) {
/* packet consumed, send it out on in_if */
struct netif *in_if;
/* check if the pbuf has room for link headers */
if (pbuf_header(p, PBUF_LINK_HLEN)) {
/* pbuf has no room for link headers, allocate an extra pbuf */
q = pbuf_alloc(PBUF_LINK, 0, PBUF_RAM);
if (q == NULL) {
LWIP_DEBUGF(LWIP_NAT_DEBUG, ("ip_nat_input: no pbuf for outgoing header\n"));
// rt_kprintf("ip_nat_input: no pbuf for outgoing header\n");
/* @todo: stats? */
pbuf_free(p);
p = NULL;
return 1;
} else {
pbuf_cat(q, p);
}
} else {
/* restore p->payload to IP header */
if (pbuf_header(p, -PBUF_LINK_HLEN)) {
LWIP_DEBUGF(LWIP_NAT_DEBUG, ("ip_nat_input: restoring header failed\n"));
// rt_kprintf("ip_nat_input: restoring header failed\n");
/* @todo: stats? */
pbuf_free(p);
p = NULL;
return 1;
}
else q = p;
}
/* if we come here, q is the pbuf to send (either points to p or to a chain) */
in_if = nat_entry.cmn->cfg->entry.in_if;
iphdr->dest.addr = nat_entry.cmn->source.addr;
ip_nat_chksum_adjust((u8_t *) & IPH_CHKSUM(iphdr),
(u8_t *) & (nat_entry.cmn->cfg->entry.out_if->ip_addr.addr), 4,
(u8_t *) & (iphdr->dest.addr), 4);
ip_nat_dbg_dump("ip_nat_input: packet back to source after nat: ", iphdr);
LWIP_DEBUGF(LWIP_NAT_DEBUG, ("ip_nat_input: sending packet on interface ("));
ip_nat_dbg_dump_ip(&(in_if->ip_addr));
LWIP_DEBUGF(LWIP_NAT_DEBUG, (")\n"));
err = in_if->output(in_if, q, (ip_addr_t *)&(iphdr->dest));
if(err != ERR_OK) {
LWIP_DEBUGF(LWIP_NAT_DEBUG,
("ip_nat_input: failed to send rewritten packet. link layer returned %d\n",
err));
// rt_kprintf("ip_nat_input: failed to send rewritten packet. link layer returned %d\n", err);
}
/* now that q (and/or p) is sent (or not), give up the reference to it
this frees the input pbuf (p) as we have consumed it. */
pbuf_free(q);
}
return consumed;
}
/** Check if one NAT entry timed out */
static void
ip_nat_check_timeout(ip_nat_entry_common_t *nat_entry)
{
if(nat_entry->ttl > 0) {
if(nat_entry->ttl != LWIP_NAT_TTL_INFINITE) {
/* this is not a 'no-timeout' entry */
if(nat_entry->ttl > LWIP_NAT_TMR_INTERVAL_SEC) {
nat_entry->ttl -= LWIP_NAT_TMR_INTERVAL_SEC;
} else {
nat_entry->ttl = 0;
}
}
}
}
/** The NAT timer function, to be called at an interval of
* LWIP_NAT_TMR_INTERVAL_SEC seconds.
*/
void
ip_nat_tmr(void)
{
int i;
LWIP_DEBUGF(LWIP_NAT_DEBUG, ("ip_nat_tmr: removing old entries\n"));
for(i = 0; i < LWIP_NAT_DEFAULT_STATE_TABLES_ICMP; i++) {
ip_nat_check_timeout((ip_nat_entry_common_t *) & ip_nat_icmp_table[i]);
}
for(i = 0; i < LWIP_NAT_DEFAULT_STATE_TABLES_TCP; i++) {
ip_nat_check_timeout((ip_nat_entry_common_t *) & ip_nat_tcp_table[i]);
}
for(i = 0; i < LWIP_NAT_DEFAULT_STATE_TABLES_UDP; i++) {
ip_nat_check_timeout((ip_nat_entry_common_t *) & ip_nat_udp_table[i]);
}
}
/** Check if we want to perform NAT with this packet. If so, send it out on
* the correct interface.
*
* @param p the packet to test/send
* @return 1: the packet has been sent using NAT,
* 0: the packet did not belong to a NAT entry
*/
u8_t
ip_nat_out(struct pbuf *p)
{
u8_t sent = 0;
err_t err;
struct ip_hdr *iphdr = p->payload;
struct icmp_echo_hdr *icmphdr;
struct tcp_hdr *tcphdr;
struct udp_hdr *udphdr;
ip_nat_conf_t *nat_config;
nat_entry_t nat_entry;
int i;
nat_entry.cmn = NULL;
ip_nat_dbg_dump("ip_nat_out: checking nat for", iphdr);
/* Check if this packet should be routed or should be translated */
nat_config = ip_nat_shallnat(iphdr);
if (nat_config != NULL ) {
if (nat_config->entry.out_if == NULL) {
LWIP_DEBUGF(LWIP_NAT_DEBUG, ("ip_nat_out: no external interface for nat table entry\n"));
} else {
switch (IPH_PROTO(iphdr))
{
case IP_PROTO_TCP:
tcphdr = (struct tcp_hdr *)ip_nat_check_header(p, sizeof(struct tcp_hdr));
if (tcphdr == NULL) {
LWIP_DEBUGF(LWIP_NAT_DEBUG,
("ip_nat_out: short tcp packet (%" U16_F " bytes) discarded\n", p->tot_len));
} else {
nat_entry.tcp = ip_nat_tcp_lookup_outgoing(nat_config, iphdr, tcphdr, 1);
if (nat_entry.tcp != NULL) {
/* Adjust TCP checksum for changing source port */
tcphdr->src = nat_entry.tcp->nport;
ip_nat_chksum_adjust((u8_t *)&(tcphdr->chksum),
(u8_t *)&(nat_entry.tcp->sport), 2, (u8_t *)&(tcphdr->src), 2);
/* Adjust TCP checksum for changing source IP address */
ip_nat_chksum_adjust((u8_t *)&(tcphdr->chksum),
(u8_t *)&(nat_entry.cmn->source.addr), 4,
(u8_t *)&(nat_entry.cmn->cfg->entry.out_if->ip_addr.addr), 4);
}
}
break;
case IP_PROTO_UDP:
udphdr = (struct udp_hdr *)ip_nat_check_header(p, sizeof(struct udp_hdr));
if (udphdr == NULL) {
LWIP_DEBUGF(LWIP_NAT_DEBUG,
("ip_nat_out: short udp packet (%" U16_F " bytes) discarded\n", p->tot_len));
} else {
nat_entry.udp = ip_nat_udp_lookup_outgoing(nat_config, iphdr, udphdr, 1);
if (nat_entry.udp != NULL) {
/* Adjust UDP checksum for changing source port */
udphdr->src = nat_entry.udp->nport;
ip_nat_chksum_adjust((u8_t *)&(udphdr->chksum),
(u8_t *)&(nat_entry.udp->sport), 2, (u8_t *) & (udphdr->src), 2);
/* Adjust UDP checksum for changing source IP address */
ip_nat_chksum_adjust((u8_t *)&(udphdr->chksum),
(u8_t *)&(nat_entry.cmn->source.addr), 4,
(u8_t *)&(nat_entry.cmn->cfg->entry.out_if->ip_addr.addr), 4);
}
}
break;
case IP_PROTO_ICMP:
icmphdr = (struct icmp_echo_hdr *)ip_nat_check_header(p, sizeof(struct icmp_echo_hdr));
if(icmphdr == NULL) {
LWIP_DEBUGF(LWIP_NAT_DEBUG,
("ip_nat_out: short icmp echo packet (%" U16_F " bytes) discarded\n", p->tot_len));
} else {
if (ICMPH_TYPE(icmphdr) == ICMP_ECHO) {
for (i = 0; i < LWIP_NAT_DEFAULT_STATE_TABLES_ICMP; i++) {
if (!ip_nat_icmp_table[i].common.ttl) {
nat_entry.icmp = &ip_nat_icmp_table[i];
ip_nat_cmn_init(nat_config, iphdr, nat_entry.cmn);
nat_entry.icmp->id = icmphdr->id;
nat_entry.icmp->seqno = icmphdr->seqno;
ip_nat_dbg_dump_icmp_nat_entry(" ip_nat_out: created new NAT entry ", nat_entry.icmp);
break;
}
}
if (NULL == nat_entry.icmp)
{
LWIP_DEBUGF(LWIP_NAT_DEBUG, ("ip_nat_out: no more NAT entries for ICMP available\n"));
}
}
}
break;
default:
break;
}
if (nat_entry.cmn != NULL) {
struct netif *out_if = nat_entry.cmn->cfg->entry.out_if;
/* Exchange the IP source address with the address of the interface
* where the packet will be sent.
*/
/* @todo: check nat_config->entry.out_if agains nat_entry.cmn->cfg->entry.out_if */
iphdr->src.addr = nat_config->entry.out_if->ip_addr.addr;
ip_nat_chksum_adjust((u8_t *) & IPH_CHKSUM(iphdr),
(u8_t *) & (nat_entry.cmn->source.addr), 4, (u8_t *) & iphdr->src.addr, 4);
ip_nat_dbg_dump("ip_nat_out: rewritten packet", iphdr);
LWIP_DEBUGF(LWIP_NAT_DEBUG, ("ip_nat_out: sending packet on interface ("));
ip_nat_dbg_dump_ip(&(out_if->ip_addr));
LWIP_DEBUGF(LWIP_NAT_DEBUG, (")\n"));
err = out_if->output(out_if, p, (ip_addr_t *)&(iphdr->dest));
if (err != ERR_OK) {
LWIP_DEBUGF(LWIP_NAT_DEBUG,
("ip_nat_out: failed to send rewritten packet. link layer returned %d\n", err));
// rt_kprintf("ip_nat_out: failed to send rewritten packet. link layer returned %d\n", err);
} else {
sent = 1;
}
}
}
}
return sent;
}
/** Initialize common parts of a NAT entry
*
* @param nat_config NAT config entry
* @param iphdr IP header from which to initialize the entry
* @param nat_entry entry to initialize
*/
static void
ip_nat_cmn_init(ip_nat_conf_t *nat_config, const struct ip_hdr *iphdr, ip_nat_entry_common_t *nat_entry)
{
LWIP_ASSERT("NULL != nat_entry", NULL != nat_entry);
LWIP_ASSERT("NULL != nat_config", NULL != nat_config);
LWIP_ASSERT("NULL != iphdr", NULL != iphdr);
nat_entry->cfg = nat_config;
nat_entry->dest = *((ip_addr_t *)&iphdr->dest);
nat_entry->source = *((ip_addr_t *)&iphdr->src);
nat_entry->ttl = LWIP_NAT_DEFAULT_TTL_SECONDS;
}
/**
* This function checks for incoming packets if we already have a NAT entry.
* If yes a pointer to the NAT entry is returned. Otherwise NULL.
*
* @param nat_config NAT configuration.
* @param iphdr The IP header.
* @param udphdr The UDP header.
* @return A pointer to an existing NAT entry or
* NULL if none is found.
*/
static ip_nat_entries_udp_t *
ip_nat_udp_lookup_incoming(const struct ip_hdr *iphdr, const struct udp_hdr *udphdr)
{
int i;
ip_nat_entries_udp_t *nat_entry = NULL;
for (i = 0; i < LWIP_NAT_DEFAULT_STATE_TABLES_UDP; i++) {
if (ip_nat_udp_table[i].common.ttl) {
if ((iphdr->src.addr == ip_nat_udp_table[i].common.dest.addr) &&
(udphdr->src == ip_nat_udp_table[i].dport) &&
(udphdr->dest == ip_nat_udp_table[i].nport)) {
nat_entry = &ip_nat_udp_table[i];
ip_nat_dbg_dump_udp_nat_entry("ip_nat_udp_lookup_incoming: found existing nat entry: ",
nat_entry);
break;
}
}
}
return nat_entry;
}
/**
* This function checks if we already have a NAT entry for this UDP connection.
* If yes the a pointer to this NAT entry is returned.
*
* @param iphdr The IP header.
* @param udphdr The UDP header.
* @param allocate If no existing NAT entry is found and this flag is true
* a NAT entry is allocated.
*/
static ip_nat_entries_udp_t *
ip_nat_udp_lookup_outgoing(ip_nat_conf_t *nat_config, const struct ip_hdr *iphdr,
const struct udp_hdr *udphdr, u8_t allocate)
{
int i;
nat_entry_t nat_entry;
int last_free = -1;
nat_entry.cmn = NULL;
for (i = 0; i < LWIP_NAT_DEFAULT_STATE_TABLES_UDP; i++) {
if (ip_nat_udp_table[i].common.ttl) {
if ((iphdr->src.addr == ip_nat_udp_table[i].common.source.addr) &&
(iphdr->dest.addr == ip_nat_udp_table[i].common.dest.addr) &&
(udphdr->src == ip_nat_udp_table[i].sport) &&
(udphdr->dest == ip_nat_udp_table[i].dport)) {
nat_entry.udp = &ip_nat_udp_table[i];
ip_nat_dbg_dump_udp_nat_entry("ip_nat_udp_lookup_outgoing: found existing nat entry: ",
nat_entry.udp);
break;
}
} else {
last_free = i;
}
}
if (nat_entry.cmn == NULL) {
if (allocate) {
if (last_free != -1) {
nat_entry.udp = &ip_nat_udp_table[last_free];
nat_entry.udp->nport = htons((u16_t) (LWIP_NAT_DEFAULT_UDP_SOURCE_PORT + i));
nat_entry.udp->sport = udphdr->src;
nat_entry.udp->dport = udphdr->dest;
ip_nat_cmn_init(nat_config, iphdr, nat_entry.cmn);
ip_nat_dbg_dump_udp_nat_entry("ip_nat_udp_lookup_outgoing: created new nat entry: ",
nat_entry.udp);
} else {
LWIP_DEBUGF(LWIP_NAT_DEBUG, ("ip_nat_udp_lookup_outgoing: no more NAT entries available\n"));
// rt_kprintf("ip_nat_udp_lookup_outgoing: no more NAT entries available\n");
}
}
}
return nat_entry.udp;
}
/**
* This function checks for incoming packets if we already have a NAT entry.
* If yes a pointer to the NAT entry is returned. Otherwise NULL.
*
* @param nat_config NAT configuration.
* @param iphdr The IP header.
* @param tcphdr The TCP header.
* @return A pointer to an existing NAT entry or NULL if none is found.
*/
static ip_nat_entries_tcp_t *
ip_nat_tcp_lookup_incoming(const struct ip_hdr *iphdr, const struct tcp_hdr *tcphdr)
{
int i;
ip_nat_entries_tcp_t *nat_entry = NULL;
for (i = 0; i < LWIP_NAT_DEFAULT_STATE_TABLES_TCP; i++) {
if (ip_nat_tcp_table[i].common.ttl) {
if ((iphdr->src.addr == ip_nat_tcp_table[i].common.dest.addr) &&
(tcphdr->src == ip_nat_tcp_table[i].dport) &&
(tcphdr->dest == ip_nat_tcp_table[i].nport)) {
nat_entry = &ip_nat_tcp_table[i];
ip_nat_dbg_dump_tcp_nat_entry("ip_nat_tcp_lookup_incoming: found existing nat entry: ",
nat_entry);
break;
}
}
}
return nat_entry;
}
/**
* This function checks if we already have a NAT entry for this TCP connection.
* If yes the a pointer to this NAT entry is returned.
*
* @param iphdr The IP header.
* @param tcphdr The TCP header.
* @param allocate If no existing NAT entry is found and this flag is true
* a NAT entry is allocated.
*/
static ip_nat_entries_tcp_t *
ip_nat_tcp_lookup_outgoing(ip_nat_conf_t *nat_config, const struct ip_hdr *iphdr,
const struct tcp_hdr *tcphdr, u8_t allocate)
{
int i;
nat_entry_t nat_entry;
int last_free = -1;
nat_entry.cmn = NULL;
for (i = 0; i < LWIP_NAT_DEFAULT_STATE_TABLES_TCP; i++) {
if (ip_nat_tcp_table[i].common.ttl) {
if ((iphdr->src.addr == ip_nat_tcp_table[i].common.source.addr) &&
(iphdr->dest.addr == ip_nat_tcp_table[i].common.dest.addr) &&
(tcphdr->src == ip_nat_tcp_table[i].sport) &&
(tcphdr->dest == ip_nat_tcp_table[i].dport)) {
nat_entry.tcp = &ip_nat_tcp_table[i];
ip_nat_dbg_dump_tcp_nat_entry("ip_nat_tcp_lookup_outgoing: found existing nat entry: ",
nat_entry.tcp);
break;
}
} else {
last_free = i;
}
}
if (nat_entry.cmn == NULL) {
if (allocate) {
if (last_free != -1) {
nat_entry.tcp = &ip_nat_tcp_table[last_free];
nat_entry.tcp->nport = htons((u16_t) (LWIP_NAT_DEFAULT_TCP_SOURCE_PORT + i));
nat_entry.tcp->sport = tcphdr->src;
nat_entry.tcp->dport = tcphdr->dest;
ip_nat_cmn_init(nat_config, iphdr, nat_entry.cmn);
ip_nat_dbg_dump_tcp_nat_entry("ip_nat_tcp_lookup_outgoing: created new nat entry: ",
nat_entry.tcp);
} else {
LWIP_DEBUGF(LWIP_NAT_DEBUG, ("ip_nat_udp_lookup_outgoing: no more NAT entries available\n"));
// rt_kprintf("ip_nat_udp_lookup_outgoing: no more NAT entries available\n");
}
}
}
return nat_entry.tcp;
}
/** Adjusts the checksum of a NAT'ed packet without having to completely recalculate it
* @todo: verify this works for little- and big-endian
*
* @param chksum points to the chksum in the packet
* @param optr points to the old data in the packet
* @param olen length of old data
* @param nptr points to the new data in the packet
* @param nlen length of new data
*/
static void
ip_nat_chksum_adjust(u8_t *chksum, const u8_t *optr, s16_t olen, const u8_t *nptr, s16_t nlen)
{
s32_t x, oldval, newval;
LWIP_ASSERT("NULL != chksum", NULL != chksum);
LWIP_ASSERT("NULL != optr", NULL != optr);
LWIP_ASSERT("NULL != nptr", NULL != nptr);
LWIP_DEBUGF(LWIP_NAT_DEBUG, ("ip_nat_chksum_adjust: chksum=%p, optr=%p, olen=%" U16_F ", nptr=%p, nlen=%" U16_F "\n",
chksum, optr, olen, nptr, nlen));
x = chksum[0] * 256 + chksum[1];
x = ~x & 0xFFFF;
while (olen) {
oldval = optr[0] * 256 + optr[1];
optr += 2;
x -= oldval & 0xffff;
if (x <= 0) {
x--;
x &= 0xffff;
}
olen -= 2;
}
while (nlen) {
newval = nptr[0] * 256 + nptr[1];
nptr += 2;
x += newval & 0xffff;
if (x & 0x10000) {
x++;
x &= 0xffff;
}
nlen -= 2;
}
x = ~x & 0xFFFF;
chksum[0] = x / 256;
chksum[1] = x & 0xff;
LWIP_DEBUGF(LWIP_NAT_DEBUG, ("ip_nat_chksum_adjust: chksum = 0x%x\n", *((u16_t *) chksum)));
}
#if defined(LWIP_DEBUG) && (LWIP_NAT_DEBUG & LWIP_DBG_ON)
/**
* This function dumps an IP address
*
* @param addr IP address
*/
static void
ip_nat_dbg_dump_ip(const ip_addr_t *addr)
{
LWIP_ASSERT("NULL != addr", NULL != addr);
LWIP_DEBUGF(LWIP_NAT_DEBUG, ("%" U16_F ".%" U16_F ".%" U16_F ".%" U16_F,
ip4_addr1(addr), ip4_addr2(addr), ip4_addr3(addr), ip4_addr4(addr)));
}
/**
* This function dumps an IP header
*
* @param msg a message to print
* @param iphdr IP header
*/
static void
ip_nat_dbg_dump(const char *msg, const struct ip_hdr *iphdr)
{
LWIP_ASSERT("NULL != msg", NULL != msg);
LWIP_ASSERT("NULL != iphdr", NULL != iphdr);
LWIP_DEBUGF(LWIP_NAT_DEBUG, ("%s: IP: (", msg));
ip_nat_dbg_dump_ip((ip_addr_t *)&(iphdr->src));
LWIP_DEBUGF(LWIP_NAT_DEBUG, (" --> "));
ip_nat_dbg_dump_ip((ip_addr_t *)&(iphdr->dest));
LWIP_DEBUGF(LWIP_NAT_DEBUG, (" id=%" U16_F ", chksum=%" U16_F ")\n",
ntohs(IPH_ID(iphdr)), ntohs(IPH_CHKSUM(iphdr))));
}
/**
* This function dumps an ICMP echo reply/recho request nat entry.
*
* @param msg a message to print
* @param nat_entry the ICMP NAT entry to print
*/
static void
ip_nat_dbg_dump_icmp_nat_entry(const char *msg, const ip_nat_entries_icmp_t *nat_entry)
{
LWIP_ASSERT("NULL != msg", NULL != msg);
LWIP_ASSERT("NULL != nat_entry", NULL != nat_entry);
LWIP_ASSERT("NULL != nat_entry->common.cfg", NULL != nat_entry->common.cfg);
LWIP_ASSERT("NULL != nat_entry->common.cfg->entry.out_if",
NULL != nat_entry->common.cfg->entry.out_if);
LWIP_DEBUGF(LWIP_NAT_DEBUG, ("%s", msg));
LWIP_DEBUGF(LWIP_NAT_DEBUG, ("ICMP : ("));
ip_nat_dbg_dump_ip(&(nat_entry->common.source));
LWIP_DEBUGF(LWIP_NAT_DEBUG, (" --> "));
ip_nat_dbg_dump_ip(&(nat_entry->common.dest));
LWIP_DEBUGF(LWIP_NAT_DEBUG, (" id=%" U16_F, ntohs(nat_entry->id)));
LWIP_DEBUGF(LWIP_NAT_DEBUG, (", seq=%" U16_F, ntohs(nat_entry->seqno)));
LWIP_DEBUGF(LWIP_NAT_DEBUG, (") mapped at ("));
ip_nat_dbg_dump_ip(&(nat_entry->common.cfg->entry.out_if->ip_addr));
LWIP_DEBUGF(LWIP_NAT_DEBUG, (" --> "));
ip_nat_dbg_dump_ip(&(nat_entry->common.dest));
LWIP_DEBUGF(LWIP_NAT_DEBUG, (" id=%" U16_F, ntohs(nat_entry->id)));
LWIP_DEBUGF(LWIP_NAT_DEBUG, (", seq=%" U16_F, ntohs(nat_entry->seqno)));
LWIP_DEBUGF(LWIP_NAT_DEBUG, (")\n"));
}
/**
* This function dumps an TCP nat entry.
*
* @param msg a message to print
* @param nat_entry the TCP NAT entry to print
*/
static void
ip_nat_dbg_dump_tcp_nat_entry(const char *msg, const ip_nat_entries_tcp_t *nat_entry)
{
LWIP_ASSERT("NULL != msg", NULL != msg);
LWIP_ASSERT("NULL != nat_entry", NULL != nat_entry);
LWIP_ASSERT("NULL != nat_entry->common.cfg", NULL != nat_entry->common.cfg);
LWIP_ASSERT("NULL != nat_entry->common.cfg->entry.out_if",
NULL != nat_entry->common.cfg->entry.out_if);
LWIP_DEBUGF(LWIP_NAT_DEBUG, ("%s", msg));
LWIP_DEBUGF(LWIP_NAT_DEBUG, ("TCP : ("));
ip_nat_dbg_dump_ip(&(nat_entry->common.source));
LWIP_DEBUGF(LWIP_NAT_DEBUG, (":%" U16_F, ntohs(nat_entry->sport)));
LWIP_DEBUGF(LWIP_NAT_DEBUG, (" --> "));
ip_nat_dbg_dump_ip(&(nat_entry->common.dest));
LWIP_DEBUGF(LWIP_NAT_DEBUG, (":%" U16_F, ntohs(nat_entry->dport)));
LWIP_DEBUGF(LWIP_NAT_DEBUG, (") mapped at ("));
ip_nat_dbg_dump_ip(&(nat_entry->common.cfg->entry.out_if->ip_addr));
LWIP_DEBUGF(LWIP_NAT_DEBUG, (":%" U16_F, ntohs(nat_entry->nport)));
LWIP_DEBUGF(LWIP_NAT_DEBUG, (" --> "));
ip_nat_dbg_dump_ip(&(nat_entry->common.dest));
LWIP_DEBUGF(LWIP_NAT_DEBUG, (":%" U16_F, ntohs(nat_entry->dport)));
LWIP_DEBUGF(LWIP_NAT_DEBUG, (")\n"));
}
/**
* This function dumps a UDP NAT entry.
*
* @param msg a message to print
* @param nat_entry the UDP NAT entry to print
*/
static void
ip_nat_dbg_dump_udp_nat_entry(const char *msg, const ip_nat_entries_udp_t *nat_entry)
{
LWIP_ASSERT("NULL != msg", NULL != msg);
LWIP_ASSERT("NULL != nat_entry", NULL != nat_entry);
LWIP_ASSERT("NULL != nat_entry->common.cfg", NULL != nat_entry->common.cfg);
LWIP_ASSERT("NULL != nat_entry->common.cfg->entry.out_if",
NULL != nat_entry->common.cfg->entry.out_if);
LWIP_DEBUGF(LWIP_NAT_DEBUG, ("%s", msg));
LWIP_DEBUGF(LWIP_NAT_DEBUG, ("UDP : ("));
ip_nat_dbg_dump_ip(&(nat_entry->common.source));
LWIP_DEBUGF(LWIP_NAT_DEBUG, (":%" U16_F, ntohs(nat_entry->sport)));
LWIP_DEBUGF(LWIP_NAT_DEBUG, (" --> "));
ip_nat_dbg_dump_ip(&(nat_entry->common.dest));
LWIP_DEBUGF(LWIP_NAT_DEBUG, (":%" U16_F, ntohs(nat_entry->dport)));
LWIP_DEBUGF(LWIP_NAT_DEBUG, (") mapped at ("));
ip_nat_dbg_dump_ip(&(nat_entry->common.cfg->entry.out_if->ip_addr));
LWIP_DEBUGF(LWIP_NAT_DEBUG, (":%" U16_F, ntohs(nat_entry->nport)));
LWIP_DEBUGF(LWIP_NAT_DEBUG, (" --> "));
ip_nat_dbg_dump_ip(&(nat_entry->common.dest));
LWIP_DEBUGF(LWIP_NAT_DEBUG, (":%" U16_F, ntohs(nat_entry->dport)));
LWIP_DEBUGF(LWIP_NAT_DEBUG, (")\n"));
}
/** Prints some info when creating a new NAT entry */
static void
ip_nat_dbg_dump_init(ip_nat_conf_t *ip_nat_cfg_new)
{
LWIP_DEBUGF(LWIP_NAT_DEBUG, ("ip_nat_init: added new NAT interface\n"));
LWIP_DEBUGF(LWIP_NAT_DEBUG, ("ip_nat_init: "));
ip_nat_dbg_dump_ip(&(ip_nat_cfg_new->entry.source_net));
LWIP_DEBUGF(LWIP_NAT_DEBUG, ("/"));
ip_nat_dbg_dump_ip(&(ip_nat_cfg_new->entry.source_netmask));
LWIP_DEBUGF(LWIP_NAT_DEBUG, ("@"));
ip_nat_dbg_dump_ip(&(ip_nat_cfg_new->entry.in_if->ip_addr));
LWIP_DEBUGF(LWIP_NAT_DEBUG, (" --> "));
ip_nat_dbg_dump_ip(&(ip_nat_cfg_new->entry.dest_net));
LWIP_DEBUGF(LWIP_NAT_DEBUG, ("/"));
ip_nat_dbg_dump_ip(&(ip_nat_cfg_new->entry.dest_netmask));
LWIP_DEBUGF(LWIP_NAT_DEBUG, ("@"));
ip_nat_dbg_dump_ip(&(ip_nat_cfg_new->entry.out_if->ip_addr));
LWIP_DEBUGF(LWIP_NAT_DEBUG, ("\n"));
}
/** Prints some info when removing a NAT entry */
static void
ip_nat_dbg_dump_remove(ip_nat_conf_t *cur)
{
LWIP_DEBUGF(LWIP_NAT_DEBUG, ("ip_nat_remove: removing existing NAT interface\n"));
LWIP_DEBUGF(LWIP_NAT_DEBUG, ("ip_nat_remove: "));
ip_nat_dbg_dump_ip(&(cur->entry.source_net));
LWIP_DEBUGF(LWIP_NAT_DEBUG, ("/"));
ip_nat_dbg_dump_ip(&(cur->entry.source_netmask));
LWIP_DEBUGF(LWIP_NAT_DEBUG, ("@"));
ip_nat_dbg_dump_ip(&(cur->entry.in_if->ip_addr));
LWIP_DEBUGF(LWIP_NAT_DEBUG, (" --> "));
ip_nat_dbg_dump_ip(&(cur->entry.dest_net));
LWIP_DEBUGF(LWIP_NAT_DEBUG, ("/"));
ip_nat_dbg_dump_ip(&(cur->entry.dest_netmask));
LWIP_DEBUGF(LWIP_NAT_DEBUG, ("@"));
ip_nat_dbg_dump_ip(&(cur->entry.out_if->ip_addr));
LWIP_DEBUGF(LWIP_NAT_DEBUG, ("\n"));
}
#endif /* defined(LWIP_DEBUG) && (LWIP_NAT_DEBUG & LWIP_DBG_ON) */
#endif /* IP_NAT */