1133 lines
		
	
	
		
			41 KiB
		
	
	
	
		
			C
		
	
	
		
			Executable File
		
	
	
	
	
			
		
		
	
	
			1133 lines
		
	
	
		
			41 KiB
		
	
	
	
		
			C
		
	
	
		
			Executable File
		
	
	
	
	
| /**
 | |
|  * 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,
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|                                                          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,
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|                                                          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"));
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| 
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|   ip_nat_tmr();
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|   sys_timeout(LWIP_NAT_TMR_INTERVAL_SEC * 1000, nat_timer, NULL);
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| }
 | |
| 
 | |
| /** Initialize this module */
 | |
| void
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| ip_nat_init(void)
 | |
| {
 | |
|   int i;
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|   extern void lwip_ip_input_set_hook(int (*hook)(struct pbuf *p, struct netif *inp));
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| 
 | |
|   /* @todo: this can be omitted since we trust static variables
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|             to be initialized to zero */
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|   for (i = 0; i < LWIP_NAT_DEFAULT_STATE_TABLES_ICMP; i++) {
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|     IPNAT_ENTRY_RESET(&ip_nat_icmp_table[i].common);
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|   }
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|   for (i = 0; i < LWIP_NAT_DEFAULT_STATE_TABLES_TCP; i++) {
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|     IPNAT_ENTRY_RESET(&ip_nat_tcp_table[i].common);
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|   }
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|   for (i = 0; i < LWIP_NAT_DEFAULT_STATE_TABLES_UDP; i++) {
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|     IPNAT_ENTRY_RESET(&ip_nat_udp_table[i].common);
 | |
|   }
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| 
 | |
|   /* we must lock scheduler to protect following code */
 | |
|   rt_enter_critical();
 | |
| 
 | |
|   /* add a lwip timer for NAT */
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|   sys_timeout(LWIP_NAT_TMR_INTERVAL_SEC * 1000, nat_timer, NULL);
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| 
 | |
|   /* un-protect */
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|   rt_exit_critical();
 | |
| }
 | |
| 
 | |
| /** Allocate a new ip_nat_conf_t item */
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| static ip_nat_conf_t*
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| ip_nat_alloc(void)
 | |
| {
 | |
|   ip_nat_conf_t *ret = (ip_nat_conf_t*)mem_malloc(sizeof(ip_nat_conf_t));
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|   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 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 nat_config NAT config entry
 | |
|  * @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 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 nat_config NAT config entry
 | |
|  * @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 */
 |