/** read the request from the socket, process it and then send the
* response back.
*/
void ProcessIncomingNATPMPPacket(int s)
{
unsigned char req[32]; /* request udp packet */
unsigned char resp[32]; /* response udp packet */
int resplen;
struct sockaddr_in senderaddr;
socklen_t senderaddrlen = sizeof(senderaddr);
int n;
char senderaddrstr[16];
n = recvfrom(s, req, sizeof(req), 0,
(struct sockaddr *)&senderaddr, &senderaddrlen);
if(n<0) {
/* EAGAIN, EWOULDBLOCK and EINTR : silently ignore (retry next time)
* other errors : log to LOG_ERR */
if(errno != EAGAIN &&
errno != EWOULDBLOCK &&
errno != EINTR) {
syslog(LOG_ERR, "recvfrom(natpmp): %m");
}
return;
}
if(!inet_ntop(AF_INET, &senderaddr.sin_addr,
senderaddrstr, sizeof(senderaddrstr))) {
syslog(LOG_ERR, "inet_ntop(natpmp): %m");
}
syslog(LOG_INFO, "NAT-PMP request received from %s:%hu %dbytes",
senderaddrstr, ntohs(senderaddr.sin_port), n);
if(n<2 || ((((req[1]-1)&~1)==0) && n<12)) {
syslog(LOG_WARNING, "discarding NAT-PMP request (too short) %dBytes",
n);
return;
}
if(req[1] & 128) {
/* discarding NAT-PMP responses silently */
return;
}
memset(resp, 0, sizeof(resp));
resplen = 8;
resp[1] = 128 + req[1]; /* response OPCODE is request OPCODE + 128 */
/* setting response TIME STAMP :
* time elapsed since its port mapping table was initialized on
* startup or reset for any other reason */
*((uint32_t *)(resp+4)) = htonl(time(NULL) - startup_time);
if(req[0] > 0) {
/* invalid version */
syslog(LOG_WARNING, "unsupported NAT-PMP version : %u",
(unsigned)req[0]);
resp[3] = 1; /* unsupported version */
} else switch(req[1]) {
case 0: /* Public address request */
syslog(LOG_INFO, "NAT-PMP public address request");
FillPublicAddressResponse(resp, senderaddr.sin_addr.s_addr);
resplen = 12;
break;
case 1: /* UDP port mapping request */
case 2: /* TCP port mapping request */
{
unsigned short iport; /* private port */
unsigned short eport; /* public port */
uint32_t lifetime; /* lifetime=0 => remove port mapping */
int r;
int proto;
char iaddr_old[16];
unsigned short iport_old;
unsigned int timestamp;
iport = ntohs(*((uint16_t *)(req+4)));
eport = ntohs(*((uint16_t *)(req+6)));
lifetime = ntohl(*((uint32_t *)(req+8)));
proto = (req[1]==1)?IPPROTO_UDP:IPPROTO_TCP;
syslog(LOG_INFO, "NAT-PMP port mapping request : "
"%hu->%s:%hu %s lifetime=%us",
eport, senderaddrstr, iport,
(req[1]==1)?"udp":"tcp", lifetime);
if(eport==0)
eport = iport;
/* TODO: accept port mapping if iport ok but eport not ok
* (and set eport correctly) */
if(lifetime == 0) {
/* remove the mapping */
if(iport == 0) {
/* remove all the mappings for this client */
int index = 0;
unsigned short eport2, iport2;
char iaddr2[16];
int proto2;
char desc[64];
while(get_redirect_rule_by_index(index, 0,
&eport2, iaddr2, sizeof(iaddr2),
&iport2, &proto2,
desc, sizeof(desc),
0, 0, ×tamp, 0, 0) >= 0) {
syslog(LOG_DEBUG, "%d %d %hu->'%s':%hu '%s'",
index, proto2, eport2, iaddr2, iport2, desc);
if(0 == strcmp(iaddr2, senderaddrstr)
&& 0 == memcmp(desc, "NAT-PMP", 7)) {
r = _upnp_delete_redir(eport2, proto2);
/* TODO : check return value */
if(r<0) {
syslog(LOG_ERR, "failed to remove port mapping");
index++;
} else {
syslog(LOG_INFO, "NAT-PMP %s port %hu mapping removed",
proto2==IPPROTO_TCP?"TCP":"UDP", eport2);
}
} else {
index++;
}
}
} else {
/* To improve the interworking between nat-pmp and
* UPnP, we should check that we remove only NAT-PMP
* mappings */
r = _upnp_delete_redir(eport, proto);
/*syslog(LOG_DEBUG, "%hu %d r=%d", eport, proto, r);*/
if(r<0) {
//syslog(LOG_ERR, "Failed to remove NAT-PMP mapping eport %hu, protocol %s", eport, (proto==IPPROTO_TCP)?"TCP":"UDP");
resp[3] = 2; /* Not Authorized/Refused */
}
}
eport = 0; /* to indicate correct removing of port mapping */
} else if(iport==0
|| !check_upnp_rule_against_permissions(upnppermlist, num_upnpperm, eport, senderaddr.sin_addr, iport)) {
resp[3] = 2; /* Not Authorized/Refused */
} else do {
r = get_redirect_rule(ext_if_name, eport, proto,
iaddr_old, sizeof(iaddr_old),
&iport_old, 0, 0, 0, 0,
×tamp, 0, 0);
if(r==0) {
if(strcmp(senderaddrstr, iaddr_old)==0
&& iport==iport_old) {
/* redirection allready existing */
syslog(LOG_INFO, "port %hu %s already redirected to %s:%hu, replacing",
eport, (proto==IPPROTO_TCP)?"tcp":"udp", iaddr_old, iport_old);
/* remove and then add again */
if(_upnp_delete_redir(eport, proto) < 0) {
syslog(LOG_ERR, "failed to remove port mapping");
break;
}
} else {
eport++;
continue;
}
}
{ /* do the redirection */
char desc[64];
#if 0
timestamp = (unsigned)(time(NULL) - startup_time)
+ lifetime;
snprintf(desc, sizeof(desc), "NAT-PMP %u", timestamp);
#else
timestamp = time(NULL) + lifetime;
snprintf(desc, sizeof(desc), "NAT-PMP %hu %s",
eport, (proto==IPPROTO_TCP)?"tcp":"udp");
#endif
/* TODO : check return code */
if(upnp_redirect_internal(NULL, eport, senderaddrstr,
iport, proto, desc,
timestamp) < 0) {
syslog(LOG_ERR, "Failed to add NAT-PMP %hu %s->%s:%hu '%s'",
eport, (proto==IPPROTO_TCP)?"tcp":"udp", senderaddrstr, iport, desc);
resp[3] = 3; /* Failure */
#if 0
} else if( !nextnatpmptoclean_eport
|| timestamp < nextnatpmptoclean_timestamp) {
nextnatpmptoclean_timestamp = timestamp;
nextnatpmptoclean_eport = eport;
nextnatpmptoclean_proto = proto;
#endif
}
break;
}
} while(r==0);
*((uint16_t *)(resp+8)) = htons(iport); /* private port */
*((uint16_t *)(resp+10)) = htons(eport); /* public port */
*((uint32_t *)(resp+12)) = htonl(lifetime); /* Port Mapping lifetime */
}
resplen = 16;
break;
default:
resp[3] = 5; /* Unsupported OPCODE */
}
n = sendto(s, resp, resplen, 0,
(struct sockaddr *)&senderaddr, sizeof(senderaddr));
if(n<0) {
syslog(LOG_ERR, "sendto(natpmp): %m");
} else if(n<resplen) {
syslog(LOG_ERR, "sendto(natpmp): sent only %d bytes out of %d",
n, resplen);
}
}
/* SendNATPMPPublicAddressChangeNotification()
* should be called when the public IP address changed */
void SendNATPMPPublicAddressChangeNotification(int * sockets, int n_sockets)
{
struct sockaddr_in sockname;
unsigned char notif[12];
int j, n;
notif[0] = 0; /* vers */
notif[1] = 128; /* OP code */
notif[2] = 0; /* result code */
notif[3] = 0; /* result code */
/* seconds since "start of epoch" :
* time elapsed since the port mapping table was initialized on
* startup or reset for any other reason */
*((uint32_t *)(notif+4)) = htonl(time(NULL) - startup_time);
#ifndef MULTIPLE_EXTERNAL_IP
FillPublicAddressResponse(notif, 0);
if(notif[3])
{
syslog(LOG_WARNING, "%s: cannot get public IP address, stopping",
"SendNATPMPPublicAddressChangeNotification");
return;
}
#endif
memset(&sockname, 0, sizeof(struct sockaddr_in));
sockname.sin_family = AF_INET;
sockname.sin_addr.s_addr = inet_addr(NATPMP_NOTIF_ADDR);
for(j=0; j<n_sockets; j++)
{
if(sockets[j] < 0)
continue;
#ifdef MULTIPLE_EXTERNAL_IP
{
struct lan_addr_s * lan_addr = lan_addrs.lh_first;
int i;
for(i=0; i<j; i++)
lan_addr = lan_addr->list.le_next;
FillPublicAddressResponse(notif, lan_addr->addr.s_addr);
}
#endif
/* Port to use in 2006 version of the NAT-PMP specification */
sockname.sin_port = htons(NATPMP_PORT);
n = sendto(sockets[j], notif, 12, 0,
(struct sockaddr *)&sockname, sizeof(struct sockaddr_in));
if(n < 0)
{
syslog(LOG_ERR, "%s: sendto(s_udp=%d): %m",
"SendNATPMPPublicAddressChangeNotification", sockets[j]);
return;
}
/* Port to use in 2008 version of the NAT-PMP specification */
sockname.sin_port = htons(NATPMP_NOTIF_PORT);
n = sendto(sockets[j], notif, 12, 0,
(struct sockaddr *)&sockname, sizeof(struct sockaddr_in));
if(n < 0)
{
syslog(LOG_ERR, "%s: sendto(s_udp=%d): %m",
"SendNATPMPPublicAddressChangeNotification", sockets[j]);
return;
}
}
}
/** read the request from the socket, process it and then send the
* response back.
*/
void ProcessIncomingNATPMPPacket(int s, unsigned char *msg_buff, int len,
struct sockaddr_in *senderaddr)
{
unsigned char *req=msg_buff; /* request udp packet */
unsigned char resp[32]; /* response udp packet */
int resplen;
int n = len;
char senderaddrstr[16];
if(!inet_ntop(AF_INET, &senderaddr->sin_addr,
senderaddrstr, sizeof(senderaddrstr))) {
syslog(LOG_ERR, "inet_ntop(natpmp): %m");
}
syslog(LOG_INFO, "NAT-PMP request received from %s:%hu %dbytes",
senderaddrstr, ntohs(senderaddr->sin_port), n);
if(n<2 || ((((req[1]-1)&~1)==0) && n<12)) {
syslog(LOG_WARNING, "discarding NAT-PMP request (too short) %dBytes",
n);
return;
}
if(req[1] & 128) {
/* discarding NAT-PMP responses silently */
return;
}
memset(resp, 0, sizeof(resp));
resplen = 8;
resp[1] = 128 + req[1]; /* response OPCODE is request OPCODE + 128 */
/* setting response TIME STAMP :
* time elapsed since its port mapping table was initialized on
* startup or reset for any other reason */
WRITENU32(resp+4, time(NULL) - startup_time);
if(req[0] > 0) {
/* invalid version */
syslog(LOG_WARNING, "unsupported NAT-PMP version : %u",
(unsigned)req[0]);
resp[3] = 1; /* unsupported version */
} else switch(req[1]) {
case 0: /* Public address request */
syslog(LOG_INFO, "NAT-PMP public address request");
FillPublicAddressResponse(resp, senderaddr->sin_addr.s_addr);
resplen = 12;
break;
case 1: /* UDP port mapping request */
case 2: /* TCP port mapping request */
{
unsigned short iport; /* private port */
unsigned short eport; /* public port */
uint32_t lifetime; /* lifetime=0 => remove port mapping */
int r;
int proto;
char iaddr_old[16];
unsigned short iport_old;
unsigned int timestamp;
iport = READNU16(req+4);
eport = READNU16(req+6);
lifetime = READNU32(req+8);
proto = (req[1]==1)?IPPROTO_UDP:IPPROTO_TCP;
syslog(LOG_INFO, "NAT-PMP port mapping request : "
"%hu->%s:%hu %s lifetime=%us",
eport, senderaddrstr, iport,
(req[1]==1)?"udp":"tcp", lifetime);
/* TODO: accept port mapping if iport ok but eport not ok
* (and set eport correctly) */
if(lifetime == 0) {
/* remove the mapping */
/* RFC6886 :
* A client MAY also send an explicit packet to request deletion of a
* mapping that is no longer needed. A client requests explicit
* deletion of a mapping by sending a message to the NAT gateway
* requesting the mapping, with the Requested Lifetime in Seconds set to
* zero. The Suggested External Port MUST be set to zero by the client
* on sending, and MUST be ignored by the gateway on reception. */
int index = 0;
unsigned short eport2, iport2;
char iaddr2[16];
int proto2;
char desc[64];
eport = 0; /* to indicate correct removing of port mapping */
while(get_redirect_rule_by_index(index, 0,
&eport2, iaddr2, sizeof(iaddr2),
&iport2, &proto2,
desc, sizeof(desc),
0, 0, ×tamp, 0, 0) >= 0) {
syslog(LOG_DEBUG, "%d %d %hu->'%s':%hu '%s'",
index, proto2, eport2, iaddr2, iport2, desc);
if(0 == strcmp(iaddr2, senderaddrstr)
&& 0 == memcmp(desc, "NAT-PMP", 7)) {
/* (iport == 0) => remove all the mappings for this client */
if((iport == 0) || ((iport == iport2) && (proto == proto2))) {
r = _upnp_delete_redir(eport2, proto2);
if(r < 0) {
syslog(LOG_ERR, "Failed to remove NAT-PMP mapping eport %hu, protocol %s",
eport2, (proto2==IPPROTO_TCP)?"TCP":"UDP");
resp[3] = 2; /* Not Authorized/Refused */
break;
} else {
syslog(LOG_INFO, "NAT-PMP %s port %hu mapping removed",
proto2==IPPROTO_TCP?"TCP":"UDP", eport2);
index--;
}
}
}
index++;
}
} else if(iport==0) {
resp[3] = 2; /* Not Authorized/Refused */
} else { /* iport > 0 && lifetime > 0 */
unsigned short eport_first = 0;
int any_eport_allowed = 0;
char desc[64];
if(eport==0) /* if no suggested external port, use same a internal port */
eport = iport;
while(resp[3] == 0) {
if(eport_first == 0) { /* first time in loop */
eport_first = eport;
} else if(eport == eport_first) { /* no eport available */
if(any_eport_allowed == 0) { /* all eports rejected by permissions */
syslog(LOG_ERR, "No allowed eport for NAT-PMP %hu %s->%s:%hu",
eport, (proto==IPPROTO_TCP)?"tcp":"udp", senderaddrstr, iport);
resp[3] = 2; /* Not Authorized/Refused */
} else { /* at least one eport allowed (but none available) */
syslog(LOG_ERR, "Failed to find available eport for NAT-PMP %hu %s->%s:%hu",
eport, (proto==IPPROTO_TCP)?"tcp":"udp", senderaddrstr, iport);
resp[3] = 4; /* Out of resources */
}
break;
}
if(!check_upnp_rule_against_permissions(upnppermlist, num_upnpperm, eport, senderaddr->sin_addr, iport)) {
eport++;
if(eport == 0) eport++; /* skip port zero */
continue;
}
any_eport_allowed = 1; /* at lease one eport is allowed */
#ifdef CHECK_PORTINUSE
if (port_in_use(ext_if_name, eport, proto, senderaddrstr, iport) > 0) {
syslog(LOG_INFO, "port %hu protocol %s already in use",
eport, (proto==IPPROTO_TCP)?"tcp":"udp");
eport++;
if(eport == 0) eport++; /* skip port zero */
continue;
}
#endif
r = get_redirect_rule(ext_if_name, eport, proto,
iaddr_old, sizeof(iaddr_old),
&iport_old, 0, 0, 0, 0,
×tamp, 0, 0);
if(r==0) {
if(strcmp(senderaddrstr, iaddr_old)==0
&& iport==iport_old) {
/* redirection already existing */
syslog(LOG_INFO, "port %hu %s already redirected to %s:%hu, replacing",
eport, (proto==IPPROTO_TCP)?"tcp":"udp", iaddr_old, iport_old);
/* remove and then add again */
if(_upnp_delete_redir(eport, proto) < 0) {
syslog(LOG_ERR, "failed to remove port mapping");
break;
}
} else {
eport++;
if(eport == 0) eport++; /* skip port zero */
continue;
}
}
/* do the redirection */
#if 0
timestamp = (unsigned)(time(NULL) - startup_time)
+ lifetime;
snprintf(desc, sizeof(desc), "NAT-PMP %u", timestamp);
#else
timestamp = time(NULL) + lifetime;
snprintf(desc, sizeof(desc), "NAT-PMP %hu %s",
eport, (proto==IPPROTO_TCP)?"tcp":"udp");
#endif
/* TODO : check return code */
if(upnp_redirect_internal(NULL, eport, senderaddrstr,
iport, proto, desc,
timestamp) < 0) {
syslog(LOG_ERR, "Failed to add NAT-PMP %hu %s->%s:%hu '%s'",
eport, (proto==IPPROTO_TCP)?"tcp":"udp", senderaddrstr, iport, desc);
resp[3] = 3; /* Failure */
}
break;
}
}
WRITENU16(resp+8, iport); /* private port */
WRITENU16(resp+10, eport); /* public port */
WRITENU32(resp+12, lifetime); /* Port Mapping lifetime */
}
resplen = 16;
break;
default:
resp[3] = 5; /* Unsupported OPCODE */
}
n = sendto_or_schedule(s, resp, resplen, 0,
(struct sockaddr *)senderaddr, sizeof(*senderaddr));
if(n<0) {
syslog(LOG_ERR, "sendto(natpmp): %m");
} else if(n<resplen) {
syslog(LOG_ERR, "sendto(natpmp): sent only %d bytes out of %d",
n, resplen);
}
}
