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Load Sharing using IP Network Address Translation (RFC 2391, LSNAT).

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This commit is contained in:
Ruslan Ermilov 2000-04-27 17:55:17 +00:00
parent 6d20a77450
commit bd69051080
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=59703
2 changed files with 105 additions and 17 deletions
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42
sbin/natd/natd.8
View File

@ -35,7 +35,7 @@ Network Address Translation Daemon
.Op Fl interface Ar interface
.Op Fl config Ar configfile
.Op Fl redirect_port Ar linkspec
.Op Fl redirect_address Ar localIP publicIP
.Op Fl redirect_address Ar linkspec
.Op Fl reverse
.Op Fl proxy_only
.Op Fl proxy_rule Ar proxyspec
@ -163,7 +163,45 @@ the incoming traffic will be directed to the last
translated local address (192.168.0.4), but outgoing
traffic to the first two addresses will still be aliased
to specified public address.
.It Fl redirect_port Ar proto Xo
.Ar targetIP Ns : Ns Xo
.Ar targetPORT Ns Oo , Ns
.Ar targetIP Ns : Ns Xo
.Ar targetPORT Ns Oo , Ns
.Ar ...
.Oc Oc
.Xc
.Xc
.Op Ar aliasIP Ns : Ns Xo
.Ar aliasPORT
.Xc
.Oo Ar remoteIP Ns
.Op : Ns Ar remotePORT
.Oc
.Xc
.It Fl redirect_address Xo
.Ar localIP Ns Oo , Ns
.Ar localIP Ns Oo , Ns
.Ar ...
.Oc Oc
.Ar publicIP
.Xc
These forms of
.Fl redirect_port
and
.Fl redirect_address
are used to transparently offload network load on a single server and
distribute the load across a pool of servers.
This function is known as
.Em LSNAT
(RFC 2391).
For example, the argument
.Pp
.Dl Ar tcp www1:http,www2:http,www3:http www:http
.Pp
means that incoming HTTP requests for host www will be transparently
redirected to one of the www1, www2 or www3, where a host is selected
simply on a round-robin basis, without regard to load on the net.
.It Fl dynamic
If the
.Fl n

80
sbin/natd/natd.c
View File

@ -1021,7 +1021,7 @@ static struct OptionInfo optionTable[] = {
{ RedirectPort,
0,
String,
"tcp|udp local_addr:local_port_range [public_addr:]public_port_range"
"tcp|udp local_addr:local_port_range[,...] [public_addr:]public_port_range"
" [remote_addr[:remote_port_range]]",
"redirect a port (or ports) for incoming traffic",
"redirect_port",
@ -1030,7 +1030,7 @@ static struct OptionInfo optionTable[] = {
{ RedirectAddress,
0,
String,
"local_addr public_addr",
"local_addr[,...] public_addr",
"define mapping between local and public addresses",
"redirect_address",
NULL },
@ -1348,6 +1348,7 @@ void SetupPortRedirect (const char* parms)
{
char buf[128];
char* ptr;
char* serverPool;
struct in_addr localAddr;
struct in_addr publicAddr;
struct in_addr remoteAddr;
@ -1362,6 +1363,7 @@ void SetupPortRedirect (const char* parms)
char* protoName;
char* separator;
int i;
struct alias_link *link = NULL;
strcpy (buf, parms);
/*
@ -1379,11 +1381,20 @@ void SetupPortRedirect (const char* parms)
if (!ptr)
errx (1, "redirect_port: missing local address");
if ( StrToAddrAndPortRange (ptr, &localAddr, protoName, &portRange) != 0 )
errx (1, "redirect_port: invalid local port range");
separator = strchr(ptr, ',');
if (separator) { /* LSNAT redirection syntax. */
localAddr.s_addr = INADDR_NONE;
localPort = ~0;
numLocalPorts = 1;
serverPool = ptr;
} else {
if ( StrToAddrAndPortRange (ptr, &localAddr, protoName, &portRange) != 0 )
errx (1, "redirect_port: invalid local port range");
localPort = GETLOPORT(portRange);
numLocalPorts = GETNUMPORTS(portRange);
localPort = GETLOPORT(portRange);
numLocalPorts = GETNUMPORTS(portRange);
serverPool = NULL;
}
/*
* Extract public port and optionally address.
@ -1446,13 +1457,30 @@ void SetupPortRedirect (const char* parms)
if (numRemotePorts == 1 && remotePort == 0)
remotePortCopy = 0;
PacketAliasRedirectPort (localAddr,
htons(localPort + i),
remoteAddr,
htons(remotePortCopy),
publicAddr,
htons(publicPort + i),
proto);
link = PacketAliasRedirectPort (localAddr,
htons(localPort + i),
remoteAddr,
htons(remotePortCopy),
publicAddr,
htons(publicPort + i),
proto);
}
/*
* Setup LSNAT server pool.
*/
if (serverPool != NULL && link != NULL) {
ptr = strtok(serverPool, ",");
while (ptr != NULL) {
if (StrToAddrAndPortRange(ptr, &localAddr, protoName, &portRange) != 0)
errx(1, "redirect_port: invalid local port range");
localPort = GETLOPORT(portRange);
if (GETNUMPORTS(portRange) != 1)
errx(1, "redirect_port: local port must be single in this context");
PacketAliasAddServer(link, localAddr, htons(localPort));
ptr = strtok(NULL, ",");
}
}
}
@ -1460,8 +1488,11 @@ void SetupAddressRedirect (const char* parms)
{
char buf[128];
char* ptr;
char* separator;
struct in_addr localAddr;
struct in_addr publicAddr;
char* serverPool;
struct alias_link *link;
strcpy (buf, parms);
/*
@ -1471,7 +1502,14 @@ void SetupAddressRedirect (const char* parms)
if (!ptr)
errx (1, "redirect_address: missing local address");
StrToAddr (ptr, &localAddr);
separator = strchr(ptr, ',');
if (separator) { /* LSNAT redirection syntax. */
localAddr.s_addr = INADDR_NONE;
serverPool = ptr;
} else {
StrToAddr (ptr, &localAddr);
serverPool = NULL;
}
/*
* Extract public address.
*/
@ -1480,7 +1518,19 @@ void SetupAddressRedirect (const char* parms)
errx (1, "redirect_address: missing public address");
StrToAddr (ptr, &publicAddr);
PacketAliasRedirectAddr (localAddr, publicAddr);
link = PacketAliasRedirectAddr(localAddr, publicAddr);
/*
* Setup LSNAT server pool.
*/
if (serverPool != NULL && link != NULL) {
ptr = strtok(serverPool, ",");
while (ptr != NULL) {
StrToAddr(ptr, &localAddr);
PacketAliasAddServer(link, localAddr, htons(~0));
ptr = strtok(NULL, ",");
}
}
}
void StrToAddr (const char* str, struct in_addr* addr)