diff options
Diffstat (limited to 'sys/netinet/libalias/alias.h')
| -rw-r--r-- | sys/netinet/libalias/alias.h | 20 |
1 files changed, 20 insertions, 0 deletions
diff --git a/sys/netinet/libalias/alias.h b/sys/netinet/libalias/alias.h index 706184552429..96d8ceec28be 100644 --- a/sys/netinet/libalias/alias.h +++ b/sys/netinet/libalias/alias.h @@ -227,6 +227,26 @@ struct mbuf *m_megapullup(struct mbuf *, int); */ #define PKT_ALIAS_UNREGISTERED_CGN 0x400 +/* + * When this bit is set, UDP uses endpoint-independent mapping (EIM), as per + * RFC 4787 ("full cone" NAT of RFC 3489). All packets from the same internal + * address:port are mapped to the same NAT address:port, regardless of their + * destination address:port. If filtering rules allow, and if + * PKT_ALIAS_DENY_INCOMING is unset, any other external address:port can also + * send to the internal address:port through its mapped NAT address:port. This + * is more compatible with applications, and can reduce the need for port + * forwarding, but less scalable as each NAT address:port can only be + * concurrently used by at most one internal address:port. + * + * When this bit is unset, UDP packets use endpoint-dependent mapping (EDM) + * ("symmetric" NAT). Each connection from a particular internal address:port + * to different external addresses:ports is mapped to a random and + * unpredictable NAT address:port. Two appplications behind EDM NATs can only + * connect to each other by port forwarding on the NAT, or tunnelling through + * an in-between server. + */ +#define PKT_ALIAS_UDP_EIM 0x800 + /* Function return codes. */ #define PKT_ALIAS_ERROR -1 #define PKT_ALIAS_OK 1 |