diff options
Diffstat (limited to 'sys/netinet/libalias/alias_db.c')
| -rw-r--r-- | sys/netinet/libalias/alias_db.c | 213 |
1 files changed, 213 insertions, 0 deletions
diff --git a/sys/netinet/libalias/alias_db.c b/sys/netinet/libalias/alias_db.c index f8baa71..8cf7da5 100644 --- a/sys/netinet/libalias/alias_db.c +++ b/sys/netinet/libalias/alias_db.c @@ -103,6 +103,16 @@ version of PacketAliasPermanentLink(). The second function implements static network address translation. + Version 3.2: July, 2000 (salander and satoh) + Added FindNewPortGroup to get contiguous range of port values. + + Added QueryUdpTcpIn and QueryUdpTcpOut to look for an aliasing + link but not actually add one. + + Added FindRtspOut, which is closely derived from FindUdpTcpOut, + except that the alias port (from FindNewPortGroup) is provided + as input. + See HISTORY file for additional revisions. $FreeBSD$ @@ -500,6 +510,9 @@ Link creation and deletion: Link search: FindLinkOut() - find link for outgoing packets FindLinkIn() - find link for incoming packets + +Port search: + FindNewPortGroup() - find an available group of ports */ /* Local prototypes */ @@ -531,11 +544,14 @@ FindLinkIn(struct in_addr, struct in_addr, u_short, u_short, int, int); #define ALIAS_PORT_BASE 0x08000 #define ALIAS_PORT_MASK 0x07fff +#define ALIAS_PORT_MASK_EVEN 0x07ffe #define GET_NEW_PORT_MAX_ATTEMPTS 20 #define GET_ALIAS_PORT -1 #define GET_ALIAS_ID GET_ALIAS_PORT +#define FIND_EVEN_ALIAS_BASE 1 + /* GetNewPort() allocates port numbers. Note that if a port number is already in use, that does not mean that it cannot be used by another link concurrently. This is because GetNewPort() looks for @@ -704,6 +720,102 @@ GetSocket(u_short port_net, int *sockfd, int link_type) } +/* FindNewPortGroup() returns a base port number for an available + range of contiguous port numbers. Note that if a port number + is already in use, that does not mean that it cannot be used by + another link concurrently. This is because FindNewPortGroup() + looks for unused triplets: (dest addr, dest port, alias port). */ + +int +FindNewPortGroup(struct in_addr dst_addr, + struct in_addr alias_addr, + u_short src_port, + u_short dst_port, + u_short port_count, + u_char proto, + u_char align) +{ + int i, j; + int max_trials; + u_short port_sys; + int link_type; + + /* + * Get link_type from protocol + */ + + switch (proto) + { + case IPPROTO_UDP: + link_type = LINK_UDP; + break; + case IPPROTO_TCP: + link_type = LINK_TCP; + break; + default: + return (0); + break; + } + + /* + * The aliasing port is automatically selected + * by one of two methods below: + */ + max_trials = GET_NEW_PORT_MAX_ATTEMPTS; + + if (packetAliasMode & PKT_ALIAS_SAME_PORTS) { + /* + * When the ALIAS_SAME_PORTS option is + * chosen, the first try will be the + * actual source port. If this is already + * in use, the remainder of the trials + * will be random. + */ + port_sys = ntohs(src_port); + + } else { + + /* First trial and all subsequent are random. */ + if (align == FIND_EVEN_ALIAS_BASE) + port_sys = random() & ALIAS_PORT_MASK_EVEN; + else + port_sys = random() & ALIAS_PORT_MASK; + + port_sys += ALIAS_PORT_BASE; + } + +/* Port number search */ + for (i = 0; i < max_trials; i++) { + + struct alias_link *search_result; + + for (j = 0; j < port_count; j++) + if (0 != (search_result = FindLinkIn(dst_addr, alias_addr, + dst_port, htons(port_sys + j), + link_type, 0))) + break; + + /* Found a good range, return base */ + if (j == port_count) + return (htons(port_sys)); + + /* Find a new base to try */ + if (align == FIND_EVEN_ALIAS_BASE) + port_sys = random() & ALIAS_PORT_MASK_EVEN; + else + port_sys = random() & ALIAS_PORT_MASK; + + port_sys += ALIAS_PORT_BASE; + } + +#ifdef DEBUG + fprintf(stderr, "PacketAlias/FindNewPortGroup(): "); + fprintf(stderr, "could not find free port(s)\n"); +#endif + + return(0); +} + static void CleanupAliasData(void) { @@ -1600,6 +1712,107 @@ FindPptpOut(struct in_addr src_addr, } +struct alias_link * +QueryUdpTcpIn(struct in_addr dst_addr, + struct in_addr alias_addr, + u_short dst_port, + u_short alias_port, + u_char proto) +{ + int link_type; + struct alias_link *link; + + switch (proto) + { + case IPPROTO_UDP: + link_type = LINK_UDP; + break; + case IPPROTO_TCP: + link_type = LINK_TCP; + break; + default: + return NULL; + break; + } + + link = FindLinkIn(dst_addr, alias_addr, + dst_port, alias_port, + link_type, 0); + + return(link); +} + + +struct alias_link * +QueryUdpTcpOut(struct in_addr src_addr, + struct in_addr dst_addr, + u_short src_port, + u_short dst_port, + u_char proto) +{ + int link_type; + struct alias_link *link; + + switch (proto) + { + case IPPROTO_UDP: + link_type = LINK_UDP; + break; + case IPPROTO_TCP: + link_type = LINK_TCP; + break; + default: + return NULL; + break; + } + + link = FindLinkOut(src_addr, dst_addr, + src_port, dst_port, + link_type, 0); + + return(link); +} + + +struct alias_link * +FindRtspOut(struct in_addr src_addr, + struct in_addr dst_addr, + u_short src_port, + u_short alias_port, + u_char proto) +{ + int link_type; + struct alias_link *link; + + switch (proto) + { + case IPPROTO_UDP: + link_type = LINK_UDP; + break; + case IPPROTO_TCP: + link_type = LINK_TCP; + break; + default: + return NULL; + break; + } + + link = FindLinkOut(src_addr, dst_addr, src_port, 0, link_type, 1); + + if (link == NULL) + { + struct in_addr alias_addr; + + alias_addr = FindAliasAddress(src_addr); + link = AddLink(src_addr, dst_addr, alias_addr, + src_port, 0, alias_port, + link_type); + } + + return(link); +} + + struct in_addr FindOriginalAddress(struct in_addr alias_addr) { |
