[libvirt] [PATCH] net: support set public ip for forward mode nat
Natanael Copa
ncopa at alpinelinux.org
Tue Dec 4 20:54:00 UTC 2012
Support setting which public ip to use for NAT via attribute
publicaddr. This will construct an iptables line using '-j SNAT
--to-source <publicaddr>' instead of '-j MASQUERADE'.
Signed-off-by: Natanael Copa <ncopa at alpinelinux.org>
---
This depends on previous sent iptables refactor patch.
http://www.mail-archive.com/libvir-list@redhat.com/msg66788.html
The validation of the publicaddr is very basic, but at least it is a
start.
Please let me know if you have a better suggestion for the attribute
name 'publicaddr' and I'll resend the patch.
Thanks!
docs/formatnetwork.html.in | 4 +++-
src/conf/network_conf.c | 33 +++++++++++++++++++++++++++++++++
src/conf/network_conf.h | 1 +
src/network/bridge_driver.c | 24 ++++++++++++++++--------
src/util/iptables.c | 31 ++++++++++++++++++++++++-------
src/util/iptables.h | 6 ++++--
6 files changed, 81 insertions(+), 18 deletions(-)
diff --git a/docs/formatnetwork.html.in b/docs/formatnetwork.html.in
index 49206dd..07f9783 100644
--- a/docs/formatnetwork.html.in
+++ b/docs/formatnetwork.html.in
@@ -125,7 +125,9 @@
other network device whether ethernet, wireless, dialup,
or VPN. If the <code>dev</code> attribute is set, the
firewall rules will restrict forwarding to the named
- device only. Inbound connections from other networks are
+ device only. If the <code>publicaddr</code> attribute is set,
+ the given source address will be used with iptables' SNAT
+ target. Inbound connections from other networks are
all prohibited; all connections between guests on the same
network, and to/from the host to the guests, are
unrestricted and not NATed.<span class="since">Since
diff --git a/src/conf/network_conf.c b/src/conf/network_conf.c
index 6ce2e63..36128ac 100644
--- a/src/conf/network_conf.c
+++ b/src/conf/network_conf.c
@@ -174,6 +174,7 @@ void virNetworkDefFree(virNetworkDefPtr def)
VIR_FREE(def->name);
VIR_FREE(def->bridge);
VIR_FREE(def->domain);
+ VIR_FREE(def->publicaddr);
for (ii = 0 ; ii < def->nForwardPfs && def->forwardPfs ; ii++) {
virNetworkForwardPfDefClear(&def->forwardPfs[ii]);
@@ -1211,6 +1212,22 @@ error:
return result;
}
+static int
+virValidPublicaddr(const char *publicaddr)
+{
+ /* only check for max len and valid chars for now */
+ const int maxlen = sizeof("123.123.123.123-123.123.123.123:65535-65534")-1;
+ int len = strlen(publicaddr);
+
+ if (len > maxlen)
+ return 0;
+
+ if (strspn(publicaddr, "0123456789.-:") < len)
+ return 0;
+
+ return 1;
+}
+
static virNetworkDefPtr
virNetworkDefParseXML(xmlXPathContextPtr ctxt)
{
@@ -1387,6 +1404,21 @@ virNetworkDefParseXML(xmlXPathContextPtr ctxt)
def->managed = 1;
}
+ def->publicaddr = virXPathString("string(./@publicaddr)", ctxt);
+ if (def->publicaddr != NULL) {
+ char *errstr = NULL;
+ if (def->forwardType != VIR_NETWORK_FORWARD_NAT) {
+ errstr = "Attribute 'publicaddr' is only valid with mode='nat'";
+ } else if (!virValidPublicaddr(def->publicaddr)) {
+ errstr = "Attribute 'publicaddr' must be in the format: ipaddr[-ipaddr][:port[-port]]";
+ }
+
+ if (errstr != NULL) {
+ virReportError(VIR_ERR_XML_ERROR, "%s", _(errstr));
+ goto error;
+ }
+ }
+
/* all of these modes can use a pool of physical interfaces */
nForwardIfs = virXPathNodeSet("./interface", ctxt, &forwardIfNodes);
nForwardPfs = virXPathNodeSet("./pf", ctxt, &forwardPfNodes);
@@ -1861,6 +1893,7 @@ char *virNetworkDefFormat(const virNetworkDefPtr def, unsigned int flags)
}
virBufferAddLit(&buf, "<forward");
virBufferEscapeString(&buf, " dev='%s'", dev);
+ virBufferEscapeString(&buf, " publicaddr='%s'", def->publicaddr);
virBufferAsprintf(&buf, " mode='%s'", mode);
if (def->forwardType == VIR_NETWORK_FORWARD_HOSTDEV) {
if (def->managed == 1)
diff --git a/src/conf/network_conf.h b/src/conf/network_conf.h
index 3e46304..76fb591 100644
--- a/src/conf/network_conf.h
+++ b/src/conf/network_conf.h
@@ -206,6 +206,7 @@ struct _virNetworkDef {
virPortGroupDefPtr portGroups;
virNetDevBandwidthPtr bandwidth;
virNetDevVlan vlan;
+ char *publicaddr;
};
typedef struct _virNetworkObj virNetworkObj;
diff --git a/src/network/bridge_driver.c b/src/network/bridge_driver.c
index 75f3c3a..04f178b 100644
--- a/src/network/bridge_driver.c
+++ b/src/network/bridge_driver.c
@@ -1438,7 +1438,8 @@ networkAddMasqueradingIptablesRules(struct network_driver *driver,
&ipdef->address,
prefix,
forwardIf,
- NULL) < 0) {
+ NULL,
+ network->def->publicaddr) < 0) {
virReportError(VIR_ERR_SYSTEM_ERROR,
forwardIf ?
_("failed to add iptables rule to enable masquerading to %s") :
@@ -1452,7 +1453,8 @@ networkAddMasqueradingIptablesRules(struct network_driver *driver,
&ipdef->address,
prefix,
forwardIf,
- "udp") < 0) {
+ "udp",
+ network->def->publicaddr) < 0) {
virReportError(VIR_ERR_SYSTEM_ERROR,
forwardIf ?
_("failed to add iptables rule to enable UDP masquerading to %s") :
@@ -1466,7 +1468,8 @@ networkAddMasqueradingIptablesRules(struct network_driver *driver,
&ipdef->address,
prefix,
forwardIf,
- "tcp") < 0) {
+ "tcp",
+ network->def->publicaddr) < 0) {
virReportError(VIR_ERR_SYSTEM_ERROR,
forwardIf ?
_("failed to add iptables rule to enable TCP masquerading to %s") :
@@ -1482,13 +1485,15 @@ networkAddMasqueradingIptablesRules(struct network_driver *driver,
&ipdef->address,
prefix,
forwardIf,
- "udp");
+ "udp",
+ network->def->publicaddr);
masqerr4:
iptablesRemoveForwardMasquerade(driver->iptables,
&ipdef->address,
prefix,
forwardIf,
- NULL);
+ NULL,
+ network->def->publicaddr);
masqerr3:
iptablesRemoveForwardAllowRelatedIn(driver->iptables,
&ipdef->address,
@@ -1518,17 +1523,20 @@ networkRemoveMasqueradingIptablesRules(struct network_driver *driver,
&ipdef->address,
prefix,
forwardIf,
- "tcp");
+ "tcp",
+ network->def->publicaddr);
iptablesRemoveForwardMasquerade(driver->iptables,
&ipdef->address,
prefix,
forwardIf,
- "udp");
+ "udp",
+ network->def->publicaddr);
iptablesRemoveForwardMasquerade(driver->iptables,
&ipdef->address,
prefix,
forwardIf,
- NULL);
+ NULL,
+ network->def->publicaddr);
iptablesRemoveForwardAllowRelatedIn(driver->iptables,
&ipdef->address,
diff --git a/src/util/iptables.c b/src/util/iptables.c
index 407ca3a..4a89673 100644
--- a/src/util/iptables.c
+++ b/src/util/iptables.c
@@ -804,6 +804,7 @@ iptablesForwardMasquerade(iptablesContext *ctx,
unsigned int prefix,
const char *physdev,
const char *protocol,
+ const char *publicaddr,
int action)
{
int ret;
@@ -833,10 +834,24 @@ iptablesForwardMasquerade(iptablesContext *ctx,
if (physdev && physdev[0])
virCommandAddArgList(cmd, "--out-interface", physdev, NULL);
- virCommandAddArgList(cmd, "--jump", "MASQUERADE", NULL);
+ /* Use --jump SNAT if public addr is specified */
+ if (publicaddr && publicaddr[0]) {
+ char tmpstr[sizeof("123.123.123.123-123.123.123.123:65535-65535")];
+ const char *portstr = "";
- if (protocol && protocol[0])
- virCommandAddArgList(cmd, "--to-ports", "1024-65535", NULL);
+ memset(tmpstr, 0, sizeof(tmpstr));
+ if (protocol && protocol[0] && (strchr(publicaddr, ':') == NULL))
+ portstr = ":1024-65535";
+ snprintf(tmpstr, sizeof(tmpstr), "%s%s", publicaddr, portstr);
+
+ virCommandAddArgList(cmd, "--jump", "SNAT",
+ "--to-source", tmpstr, NULL);
+ } else {
+ virCommandAddArgList(cmd, "--jump", "MASQUERADE", NULL);
+
+ if (protocol && protocol[0])
+ virCommandAddArgList(cmd, "--to-ports", "1024-65535", NULL);
+ }
ret = iptablesCommandRunAndFree(cmd);
VIR_FREE(networkstr);
@@ -861,9 +876,10 @@ iptablesAddForwardMasquerade(iptablesContext *ctx,
virSocketAddr *netaddr,
unsigned int prefix,
const char *physdev,
- const char *protocol)
+ const char *protocol,
+ const char *publicaddr)
{
- return iptablesForwardMasquerade(ctx, netaddr, prefix, physdev, protocol, ADD);
+ return iptablesForwardMasquerade(ctx, netaddr, prefix, physdev, protocol, publicaddr, ADD);
}
/**
@@ -884,9 +900,10 @@ iptablesRemoveForwardMasquerade(iptablesContext *ctx,
virSocketAddr *netaddr,
unsigned int prefix,
const char *physdev,
- const char *protocol)
+ const char *protocol,
+ const char *publicaddr)
{
- return iptablesForwardMasquerade(ctx, netaddr, prefix, physdev, protocol, REMOVE);
+ return iptablesForwardMasquerade(ctx, netaddr, prefix, physdev, protocol, publicaddr, REMOVE);
}
diff --git a/src/util/iptables.h b/src/util/iptables.h
index e54f8b1..a9d2772 100644
--- a/src/util/iptables.h
+++ b/src/util/iptables.h
@@ -105,12 +105,14 @@ int iptablesAddForwardMasquerade (iptablesContext *ctx,
virSocketAddr *netaddr,
unsigned int prefix,
const char *physdev,
- const char *protocol);
+ const char *protocol,
+ const char *publicaddr);
int iptablesRemoveForwardMasquerade (iptablesContext *ctx,
virSocketAddr *netaddr,
unsigned int prefix,
const char *physdev,
- const char *protocol);
+ const char *protocol,
+ const char *publicaddr);
int iptablesAddOutputFixUdpChecksum (iptablesContext *ctx,
const char *iface,
int port);
--
1.8.0.1
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