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lwip/napt: Added option to enable or disable Port mapping in NAPT.
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@espressif-abhikroy
espressif-abhikroy committed Sep 18, 2023
1 parent 7896c6c commit 6fba06a
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Showing 2 changed files with 38 additions and 3 deletions.
40 changes: 37 additions & 3 deletions src/core/ipv4/ip4_napt.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -76,6 +76,7 @@ struct napt_table {
u16_t next, prev;
};

#if IP_NAPT_PORTMAP
struct portmap_table {
u32_t maddr;
u32_t daddr;
Expand All @@ -84,15 +85,20 @@ struct portmap_table {
u8_t proto;
u8_t valid;
};
#endif

static u16_t napt_list = NO_IDX, napt_list_last = NO_IDX, napt_free = 0;

static struct napt_table *ip_napt_table = NULL;
#if IP_NAPT_PORTMAP
static struct portmap_table *ip_portmap_table = NULL;
#endif

static int nr_active_napt_tcp = 0, nr_active_napt_udp = 0, nr_active_napt_icmp = 0;
static uint16_t ip_napt_max = 0;
#if IP_NAPT_PORTMAP
static uint8_t ip_portmap_max = 0;
#endif

#if NAPT_DEBUG
/* Print NAPT table using LWIP_DEBUGF
Expand Down Expand Up @@ -130,6 +136,7 @@ napt_debug_print(void)
}
#endif /* NAPT_DEBUG */


/**
* Deallocates the NAPT tables.
*
Expand All @@ -138,8 +145,10 @@ static void
ip_napt_deinit(void)
{
mem_free(ip_napt_table);
#if IP_NAPT_PORTMAP
mem_free(ip_portmap_table);
ip_portmap_table = NULL;
#endif
ip_napt_table = NULL;
}

Expand All @@ -154,13 +163,21 @@ ip_napt_init(uint16_t max_nat, uint8_t max_portmap)
{
u16_t i;

#if IP_NAPT_PORTMAP
if (ip_portmap_table == NULL && ip_napt_table == NULL) {
ip_napt_max = max_nat;
ip_portmap_max = max_portmap;
#else
if (ip_napt_table == NULL) {
#endif
ip_napt_max = max_nat;

ip_napt_table = (struct napt_table*)mem_calloc(ip_napt_max, sizeof(struct napt_table[1]));
#if IP_NAPT_PORTMAP
ip_portmap_table = (struct portmap_table*)mem_calloc(ip_portmap_max, sizeof(struct portmap_table[1]));
assert(ip_portmap_table != NULL && ip_napt_table != NULL);
#else
assert(ip_napt_table != NULL);
#endif

for (i = 0; i < ip_napt_max - 1; i++)
ip_napt_table[i].next = i + 1;
Expand Down Expand Up @@ -342,9 +359,10 @@ ip_napt_find_port(u8_t proto, u16_t port)
}
return 0;
}

#if IP_NAPT_PORTMAP
static struct portmap_table *
ip_portmap_find(u8_t proto, u16_t mport);
#endif

static u8_t
tcp_listening(u16_t port)
Expand All @@ -353,8 +371,10 @@ tcp_listening(u16_t port)
for (t = tcp_listen_pcbs.listen_pcbs; t; t = t->next)
if (t->local_port == port)
return 1;
#if IP_NAPT_PORTMAP
if (ip_portmap_find(IP_PROTO_TCP, port))
return 1;
#endif
return 0;
}
#endif /* LWIP_TCP */
Expand All @@ -367,8 +387,10 @@ udp_listening(u16_t port)
for (pcb = udp_pcbs; pcb; pcb = pcb->next)
if (pcb->local_port == port)
return 1;
#if IP_NAPT_PORTMAP
if (ip_portmap_find(IP_PROTO_UDP, port))
return 1;
#endif
return 0;
}
#endif /* LWIP_UDP */
Expand Down Expand Up @@ -508,6 +530,7 @@ ip_napt_add(u8_t proto, u32_t src, u16_t sport, u32_t dest, u16_t dport)
return 0;
}

#if IP_NAPT_PORTMAP
u8_t
ip_portmap_add(u8_t proto, u32_t maddr, u16_t mport, u32_t daddr, u16_t dport)
{
Expand Down Expand Up @@ -573,6 +596,7 @@ ip_portmap_remove(u8_t proto, u16_t mport)
last->valid = 0;
return 1;
}
#endif /* IP_NAPT_PORTMAP */

#if LWIP_TCP
static void
Expand Down Expand Up @@ -627,7 +651,9 @@ ip_napt_modify_addr(struct ip_hdr *iphdr, ip4_addr_p_t *field, u32_t newval)
void
ip_napt_recv(struct pbuf *p, struct ip_hdr *iphdr)
{
#if IP_NAPT_PORTMAP
struct portmap_table *m;
#endif
struct napt_table *t;
#if LWIP_ICMP
/* NAPT for ICMP Echo Request using identifier */
Expand All @@ -649,7 +675,6 @@ ip_napt_recv(struct pbuf *p, struct ip_hdr *iphdr)
if (IPH_PROTO(iphdr) == IP_PROTO_TCP) {
struct tcp_hdr *tcphdr = (struct tcp_hdr *)((u8_t *)p->payload + IPH_HL(iphdr) * 4);


LWIP_DEBUGF(NAPT_DEBUG, ("ip_napt_recv\n"));
LWIP_DEBUGF(NAPT_DEBUG, ("src: %"U16_F".%"U16_F".%"U16_F".%"U16_F", dest: %"U16_F".%"U16_F".%"U16_F".%"U16_F", \n",
ip4_addr1_16(&iphdr->src), ip4_addr2_16(&iphdr->src),
Expand All @@ -661,6 +686,7 @@ ip_napt_recv(struct pbuf *p, struct ip_hdr *iphdr)
lwip_htons(tcphdr->src),
lwip_htons(tcphdr->dest)));

#if IP_NAPT_PORTMAP
m = ip_portmap_find(IP_PROTO_TCP, tcphdr->dest);
if (m) {
/* packet to mapped port: rewrite destination */
Expand All @@ -670,6 +696,7 @@ ip_napt_recv(struct pbuf *p, struct ip_hdr *iphdr)
ip_napt_modify_addr(iphdr, &iphdr->dest, m->daddr);
return;
}
#endif
t = ip_napt_find(IP_PROTO_TCP, iphdr->src.addr, tcphdr->src, tcphdr->dest, 1);
if (!t)
return; /* Unknown TCP session; do nothing */
Expand All @@ -694,6 +721,8 @@ ip_napt_recv(struct pbuf *p, struct ip_hdr *iphdr)
#if LWIP_UDP
if (IPH_PROTO(iphdr) == IP_PROTO_UDP) {
struct udp_hdr *udphdr = (struct udp_hdr *)((u8_t *)p->payload + IPH_HL(iphdr) * 4);

#if IP_NAPT_PORTMAP
m = ip_portmap_find(IP_PROTO_UDP, udphdr->dest);
if (m) {
/* packet to mapped port: rewrite destination */
Expand All @@ -703,6 +732,7 @@ ip_napt_recv(struct pbuf *p, struct ip_hdr *iphdr)
ip_napt_modify_addr(iphdr, &iphdr->dest, m->daddr);
return;
}
#endif
t = ip_napt_find(IP_PROTO_UDP, iphdr->src.addr, udphdr->src, udphdr->dest, 1);
if (!t)
return; /* Unknown session; do nothing */
Expand Down Expand Up @@ -742,6 +772,7 @@ ip_napt_forward(struct pbuf *p, struct ip_hdr *iphdr, struct netif *inp, struct
struct tcp_hdr *tcphdr = (struct tcp_hdr *)((u8_t *)p->payload + IPH_HL(iphdr) * 4);
u16_t mport;

#if IP_NAPT_PORTMAP
struct portmap_table *m = ip_portmap_find_dest(IP_PROTO_TCP, tcphdr->src, iphdr->src.addr);
if (m) {
/* packet from port-mapped dest addr/port: rewrite source to this node */
Expand All @@ -751,6 +782,7 @@ ip_napt_forward(struct pbuf *p, struct ip_hdr *iphdr, struct netif *inp, struct
ip_napt_modify_addr(iphdr, &iphdr->src, m->maddr);
return ERR_OK;
}
#endif
if ((TCPH_FLAGS(tcphdr) & (TCP_SYN|TCP_ACK)) == TCP_SYN &&
PP_NTOHS(tcphdr->src) >= 1024) {
/* Register new TCP session to NAPT */
Expand Down Expand Up @@ -789,6 +821,7 @@ ip_napt_forward(struct pbuf *p, struct ip_hdr *iphdr, struct netif *inp, struct
struct udp_hdr *udphdr = (struct udp_hdr *)((u8_t *)p->payload + IPH_HL(iphdr) * 4);
u16_t mport;

#if IP_NAPT_PORTMAP
struct portmap_table *m = ip_portmap_find_dest(IP_PROTO_UDP, udphdr->src, iphdr->src.addr);
if (m) {
/* packet from port-mapped dest addr/port: rewrite source to this node */
Expand All @@ -799,6 +832,7 @@ ip_napt_forward(struct pbuf *p, struct ip_hdr *iphdr, struct netif *inp, struct
ip_napt_modify_addr(iphdr, &iphdr->src, m->maddr);
return ERR_OK;
}
#endif /* IP_NAPT_PORTMAP */
if (PP_NTOHS(udphdr->src) >= 1024) {
/* Register new UDP session */
mport = ip_napt_add(IP_PROTO_UDP, iphdr->src.addr, udphdr->src,
Expand Down
1 change: 1 addition & 0 deletions test/unit/lwipopts.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -147,6 +147,7 @@ void dhcp_free_vendor_class_identifier(void);
#define LWIP_RAND() (esp_random())
#include "lwip/arch.h"
u32_t esp_random(void);
#define IP_NAPT_PORTMAP 1
#endif /* IP_NAPT */

/* ESP debug options */
Expand Down

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