[pve-devel] [PATCH pve-network 4/4] subnet: dhcp: do not allow overlapping dhcp ranges

[Stefan Hanreich]

Check for overlapping DHCP ranges and reject them if there are any
overlaps. If we can be certain that there are no overlapping DHCP
ranges this saves us from running into errors later in IPAM modules
where overlapping DHCP ranges are not allowed.

Signed-off-by: Stefan Hanreich <s.hanreich at proxmox.com>
---
 src/PVE/Network/SDN/SubnetPlugin.pm | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/src/PVE/Network/SDN/SubnetPlugin.pm b/src/PVE/Network/SDN/SubnetPlugin.pm
index c842450..b911d69 100644
--- a/src/PVE/Network/SDN/SubnetPlugin.pm
+++ b/src/PVE/Network/SDN/SubnetPlugin.pm
@@ -3,7 +3,7 @@ package PVE::Network::SDN::SubnetPlugin;
 use strict;
 use warnings;
 
-use Net::IP;
+use Net::IP qw($IP_NO_OVERLAP);
 use Net::Subnet qw(subnet_matcher);
 
 use PVE::Cluster qw(cfs_read_file cfs_write_file cfs_lock_file);
@@ -82,6 +82,8 @@ sub validate_dhcp_ranges {
 
     my $dhcp_ranges = PVE::Network::SDN::Subnets::get_dhcp_ranges($subnet);
 
+    my $validated_ranges = [];
+
     foreach my $dhcp_range (@$dhcp_ranges) {
 	my $dhcp_start = $dhcp_range->{'start-address'};
 	my $dhcp_end = $dhcp_range->{'end-address'};
@@ -102,6 +104,15 @@ sub validate_dhcp_ranges {
 
 	raise_param_exc({ 'dhcp-range' => "start-address $dhcp_start is not in subnet $cidr" }) if !$subnet_matcher->($dhcp_start);
 	raise_param_exc({ 'dhcp-range' => "end-address $dhcp_end is not in subnet $cidr" }) if !$subnet_matcher->($dhcp_end);
+
+	my $ip_range = Net::IP->new("$dhcp_range->{'start-address'} - $dhcp_range->{'end-address'}");
+	for my $other_range (@$validated_ranges) {
+	    if ($ip_range->overlaps($other_range) != $Net::IP::IP_NO_OVERLAP) {
+		raise_param_exc({ 'dhcp-range' => "dhcp ranges must not overlap" });
+	    }
+	}
+
+	push @$validated_ranges, $ip_range;
     }
 }
 
-- 
2.39.5