[libvirt] [PATCH 2/2] network: split setup of ipv4 and ipv6 top level chains

Daniel P. Berrangé posted 2 patches 35 weeks ago

[libvirt] [PATCH 2/2] network: split setup of ipv4 and ipv6 top level chains

Posted by Daniel P. Berrangé 35 weeks ago
During startup libvirtd creates top level chains for both ipv4
and ipv6 protocols. If this fails for any reason then startup
of virtual networks is blocked.

The default virtual network, however, only requires use of ipv4
and some servers have ipv6 disabled so it is expected that ipv6
chain creation will fail. There could equally be servers with
no ipv4, only ipv6.

This patch thus makes error reporting a little more fine grained
so that it works more sensibly when either ipv4 or ipv6 is
disabled on the server. Only the protocols that are actually
used by the virtual network have errors reported.

Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
---
 src/network/bridge_driver_linux.c | 36 +++++++++++++++++++++++++------
 src/util/viriptables.c            | 14 ++++--------
 src/util/viriptables.h            |  2 +-
 3 files changed, 34 insertions(+), 18 deletions(-)

diff --git a/src/network/bridge_driver_linux.c b/src/network/bridge_driver_linux.c
index 04b9c079ff..4e2320ea0a 100644
--- a/src/network/bridge_driver_linux.c
+++ b/src/network/bridge_driver_linux.c
@@ -35,10 +35,12 @@ VIR_LOG_INIT("network.bridge_driver_linux");
 
 #define PROC_NET_ROUTE "/proc/net/route"
 
-static virErrorPtr errInit;
+static virErrorPtr errInitV4;
+static virErrorPtr errInitV6;
 
-void networkPreReloadFirewallRules(bool startup)
+int networkPreReloadFirewallRules(bool startup)
 {
+    bool created = false;
     int ret;
 
     /* We create global rules upfront as we don't want
@@ -49,11 +51,21 @@ void networkPreReloadFirewallRules(bool startup)
      * of starting the network though as that makes them
      * more likely to be seen by a human
      */
-    ret = iptablesSetupPrivateChains();
+    ret = iptablesSetupPrivateChains(VIR_FIREWALL_LAYER_IPV4);
     if (ret < 0) {
-        errInit = virSaveLastError();
+        errInitV4 = virSaveLastError();
         virResetLastError();
     }
+    if (ret)
+        created = true;
+
+    ret = iptablesSetupPrivateChains(VIR_FIREWALL_LAYER_IPV6);
+    if (ret < 0) {
+        errInitV6 = virSaveLastError();
+        virResetLastError();
+    }
+    if (ret)
+        created = true;
 
     /*
      * If this is initial startup, and we just created the
@@ -68,7 +80,7 @@ void networkPreReloadFirewallRules(bool startup)
      * rules will be present. Thus we can safely just tell it
      * to always delete from the builin chain
      */
-    if (startup && ret == 1)
+    if (startup && created)
         iptablesSetDeletePrivate(false);
 }
 
@@ -683,8 +695,18 @@ int networkAddFirewallRules(virNetworkDefPtr def)
     virFirewallPtr fw = NULL;
     int ret = -1;
 
-    if (errInit) {
-        virSetError(errInit);
+    if (errInitV4 &&
+        (virNetworkDefGetIPByIndex(def, AF_INET, 0) ||
+         virNetworkDefGetRouteByIndex(def, AF_INET, 0))) {
+        virSetError(errInitV4);
+        return -1;
+    }
+
+    if (errInitV6 &&
+        (virNetworkDefGetIPByIndex(def, AF_INET6, 0) ||
+         virNetworkDefGetRouteByIndex(def, AF_INET6, 0) ||
+         def->ipv6nogw)) {
+        virSetError(errInitV6);
         return -1;
     }
 
diff --git a/src/util/viriptables.c b/src/util/viriptables.c
index d67b640a3b..0e3c0ad73a 100644
--- a/src/util/viriptables.c
+++ b/src/util/viriptables.c
@@ -127,7 +127,7 @@ iptablesPrivateChainCreate(virFirewallPtr fw,
 
 
 int
-iptablesSetupPrivateChains(void)
+iptablesSetupPrivateChains(virFirewallLayer layer)
 {
     virFirewallPtr fw = NULL;
     int ret = -1;
@@ -143,17 +143,11 @@ iptablesSetupPrivateChains(void)
     };
     bool changed = false;
     iptablesGlobalChainData data[] = {
-        { VIR_FIREWALL_LAYER_IPV4, "filter",
+        { layer, "filter",
           filter_chains, ARRAY_CARDINALITY(filter_chains), &changed },
-        { VIR_FIREWALL_LAYER_IPV4, "nat",
+        { layer, "nat",
           natmangle_chains, ARRAY_CARDINALITY(natmangle_chains), &changed },
-        { VIR_FIREWALL_LAYER_IPV4, "mangle",
-          natmangle_chains, ARRAY_CARDINALITY(natmangle_chains), &changed },
-        { VIR_FIREWALL_LAYER_IPV6, "filter",
-          filter_chains, ARRAY_CARDINALITY(filter_chains), &changed },
-        { VIR_FIREWALL_LAYER_IPV6, "nat",
-          natmangle_chains, ARRAY_CARDINALITY(natmangle_chains), &changed },
-        { VIR_FIREWALL_LAYER_IPV6, "mangle",
+        { layer, "mangle",
           natmangle_chains, ARRAY_CARDINALITY(natmangle_chains), &changed },
     };
     size_t i;
diff --git a/src/util/viriptables.h b/src/util/viriptables.h
index 903f390f89..e680407ec8 100644
--- a/src/util/viriptables.h
+++ b/src/util/viriptables.h
@@ -24,7 +24,7 @@
 # include "virsocketaddr.h"
 # include "virfirewall.h"
 
-int              iptablesSetupPrivateChains      (void);
+int              iptablesSetupPrivateChains      (virFirewallLayer layer);
 
 void             iptablesSetDeletePrivate        (bool pvt);
 
-- 
2.20.1

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Re: [libvirt] [PATCH 2/2] network: split setup of ipv4 and ipv6 top level chains

Posted by Michal Privoznik 35 weeks ago
On 3/18/19 6:47 PM, Daniel P. Berrangé wrote:
> During startup libvirtd creates top level chains for both ipv4
> and ipv6 protocols. If this fails for any reason then startup
> of virtual networks is blocked.
> 
> The default virtual network, however, only requires use of ipv4
> and some servers have ipv6 disabled so it is expected that ipv6
> chain creation will fail. There could equally be servers with
> no ipv4, only ipv6.
> 
> This patch thus makes error reporting a little more fine grained
> so that it works more sensibly when either ipv4 or ipv6 is
> disabled on the server. Only the protocols that are actually
> used by the virtual network have errors reported.
> 
> Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
> ---
>   src/network/bridge_driver_linux.c | 36 +++++++++++++++++++++++++------
>   src/util/viriptables.c            | 14 ++++--------
>   src/util/viriptables.h            |  2 +-
>   3 files changed, 34 insertions(+), 18 deletions(-)
> 
> diff --git a/src/network/bridge_driver_linux.c b/src/network/bridge_driver_linux.c
> index 04b9c079ff..4e2320ea0a 100644
> --- a/src/network/bridge_driver_linux.c
> +++ b/src/network/bridge_driver_linux.c
> @@ -35,10 +35,12 @@ VIR_LOG_INIT("network.bridge_driver_linux");
>   
>   #define PROC_NET_ROUTE "/proc/net/route"
>   
> -static virErrorPtr errInit;
> +static virErrorPtr errInitV4;
> +static virErrorPtr errInitV6;
>   
> -void networkPreReloadFirewallRules(bool startup)
> +int networkPreReloadFirewallRules(bool startup)

I guess you didn't mean to do this change.

>   {
> +    bool created = false;
>       int ret;
>   
>       /* We create global rules upfront as we don't want
> @@ -49,11 +51,21 @@ void networkPreReloadFirewallRules(bool startup)
>        * of starting the network though as that makes them
>        * more likely to be seen by a human
>        */
> -    ret = iptablesSetupPrivateChains();
> +    ret = iptablesSetupPrivateChains(VIR_FIREWALL_LAYER_IPV4);
>       if (ret < 0) {
> -        errInit = virSaveLastError();
> +        errInitV4 = virSaveLastError();
>           virResetLastError();
>       }
> +    if (ret)

Again, small nitpick, if (ret > 0).

> +        created = true;
> +
> +    ret = iptablesSetupPrivateChains(VIR_FIREWALL_LAYER_IPV6);
> +    if (ret < 0) {
> +        errInitV6 = virSaveLastError();
> +        virResetLastError();
> +    }
> +    if (ret)
> +        created = true;
>   

This fixes my usecase, so ACK

Michal

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