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[components][net][lwip-nat] Fix translated port allocation and adapt … #11831

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[components][net][lwip-nat] Fix translated port allocation and adapt … #11831

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52 changes: 41 additions & 11 deletions components/net/lwip-nat/ipv4_nat.c
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Original file line number Diff line number Diff line change
Expand Up @@ -77,11 +77,13 @@
#include "lwip/netif.h"
#include "lwip/ip_addr.h"
#include "lwip/icmp.h"
#include "lwip/tcp_impl.h"
/* lwIP 2.1 adaptation: tcp_impl.h was renamed/moved to prot/tcp.h (SiFli local modification) */
#include "lwip/prot/tcp.h"
#include "lwip/udp.h"
#include "lwip/mem.h"
#include "lwip/sys.h"
#include "lwip/timers.h"
/* lwIP 2.1 adaptation: timers.h was renamed/moved to timeouts.h (SiFli local modification) */
#include "lwip/timeouts.h"
#include "netif/etharp.h"

#include <limits.h>
Expand Down Expand Up @@ -371,8 +373,15 @@ 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) {
/*
* SiFli local modification
* Original RT-Thread implementation (NAT if either source or dest
* matches the rule).
* Changed to && locally: NAT is applied only when both the source and
* dest networks match the rule.
*/
if (ip_addr_netcmp(&(iphdr->dest), &(nat_config->entry.dest_net),
&(nat_config->entry.dest_netmask)) ||
&(nat_config->entry.dest_netmask)) &&
ip_addr_netcmp(&(iphdr->src), &(nat_config->entry.source_net),
&(nat_config->entry.source_netmask))) {
break;
Expand Down Expand Up @@ -679,18 +688,37 @@ ip_nat_out(struct pbuf *p)
("ip_nat_out: short icmp echo packet (%" U16_F " bytes) discarded\n", p->tot_len));
} else {
if (ICMPH_TYPE(icmphdr) == ICMP_ECHO) {
/*
* SiFli local modification
* Original RT-Thread implementation (drops new ICMP requests when
* the table is full).
* Changed locally: when no free slot is found, evict the oldest entry
* (smallest ttl) using LRU and reuse its slot, so new echo requests
* are not dropped when the ICMP table is full.
*/
int oldest = -1;
s32_t oldest_ttl = LWIP_NAT_TTL_INFINITE;

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 (ip_nat_icmp_table[i].common.ttl < oldest_ttl) {
oldest = i;
oldest_ttl = ip_nat_icmp_table[i].common.ttl;
}
}
if (nat_entry.icmp == NULL && oldest >= 0) {
nat_entry.icmp = &ip_nat_icmp_table[oldest];
IPNAT_ENTRY_RESET(&nat_entry.icmp->common);
}
if (NULL == nat_entry.icmp)
{
if (nat_entry.icmp != NULL) {
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);
} else {
LWIP_DEBUGF(LWIP_NAT_DEBUG, ("ip_nat_out: no more NAT entries for ICMP available\n"));
}
}
Expand Down Expand Up @@ -817,7 +845,8 @@ ip_nat_udp_lookup_outgoing(ip_nat_conf_t *nat_config, const struct ip_hdr *iphdr
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));
/* SiFli local modification */
nat_entry.udp->nport = htons((u16_t) (LWIP_NAT_DEFAULT_UDP_SOURCE_PORT + last_free));
nat_entry.udp->sport = udphdr->src;
nat_entry.udp->dport = udphdr->dest;
ip_nat_cmn_init(nat_config, iphdr, nat_entry.cmn);
Expand Down Expand Up @@ -902,7 +931,8 @@ ip_nat_tcp_lookup_outgoing(ip_nat_conf_t *nat_config, const struct ip_hdr *iphdr
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));
/* SiFli local modification */
nat_entry.tcp->nport = htons((u16_t) (LWIP_NAT_DEFAULT_TCP_SOURCE_PORT + last_free));
nat_entry.tcp->sport = tcphdr->src;
nat_entry.tcp->dport = tcphdr->dest;
ip_nat_cmn_init(nat_config, iphdr, nat_entry.cmn);
Expand Down
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