Fix live activation of Linux bond interfaces

ⓘ Create and configure missing bond devices with ip link, attach partner interfaces before assigning addresses, avoid legacy module auto-creation when ip is available, and add regression coverage.

Ref.: https://github.com/webmin/webmin/pull/2777

net/linux-lib.pl

@@ -258,7 +258,44 @@ if (&has_command("ip") && $a->{'virtual'} ne '' && !$a->{'up'}) {
 	return;
 	}
 
-if (!&has_command("ifconfig") && &has_command("ip")) {
+if (&has_command("ip") && $a->{'bond'} && $a->{'up'} && !$old) {
+	# Create the bond before assigning addresses to it.
+	my $bcmd = "ip link add ".quotemeta($a->{'name'})." type bond";
+	if (defined($a->{'mode'}) && $a->{'mode'} ne '') {
+		$bcmd .= " mode ".quotemeta(&bond_mode_name($a->{'mode'}));
+		}
+	if ($a->{'miimon'}) {
+		$bcmd .= " miimon ".quotemeta($a->{'miimon'});
+		}
+	if ($a->{'updelay'}) {
+		$bcmd .= " updelay ".quotemeta($a->{'updelay'});
+		}
+	if ($a->{'downdelay'}) {
+		$bcmd .= " downdelay ".quotemeta($a->{'downdelay'});
+		}
+	my $out = &backquote_logged("$bcmd 2>&1");
+	&error("Failed to create bond device : $out") if ($?);
+	foreach my $slave (grep { $_ ne '' } split(/\s+/, $a->{'partner'})) {
+		$bcmd = "ip link set dev ".quotemeta($slave)." down";
+		$out = &backquote_logged("$bcmd 2>&1");
+		&error("Failed to bring down bond slave : $out") if ($?);
+		$bcmd = "ip link set dev ".quotemeta($slave)." master ".
+			quotemeta($a->{'name'});
+		$out = &backquote_logged("$bcmd 2>&1");
+		&error("Failed to add bond slave : $out") if ($?);
+		$bcmd = "ip link set dev ".quotemeta($slave)." up";
+		$out = &backquote_logged("$bcmd 2>&1");
+		&error("Failed to bring up bond slave : $out") if ($?);
+		}
+	if ($a->{'primary'}) {
+		$bcmd = "ip link set dev ".quotemeta($a->{'name'}).
+			" type bond primary ".quotemeta($a->{'primary'});
+		$out = &backquote_logged("$bcmd 2>&1");
+		&error("Failed to set bond primary interface : $out") if ($?);
+		}
+	}
+
+if (($a->{'bond'} || !&has_command("ifconfig")) && &has_command("ip")) {
 	# For a real interface, activate or de-activate the link
 	if ($a->{'virtual'} eq '' && $a->{'up'} && (!$old || !$old->{'up'})) {
 		# Bring up
@@ -646,6 +683,19 @@ local $out = &backquote_logged("$cmd 2>&1");
 &error($out) if ($?);
 }
 
+# bond_mode_name(mode)
+# Convert Webmin's numeric bonding mode to the name expected by ip(8).
+sub bond_mode_name
+{
+my ($mode) = @_;
+my @modes = ("balance-rr", "active-backup", "balance-xor", "broadcast",
+	     "802.3ad", "balance-tlb", "balance-alb");
+if ($mode =~ /^\d+$/ && defined($modes[$mode])) {
+	return $modes[$mode];
+	}
+return $mode eq "activebackup" ? "active-backup" : $mode;
+}
+
 # Tries to unload the module
 # unload_module(name)
 sub unload_module

net/save_bifc.cgi

@@ -377,7 +377,7 @@ else {
 			$err && &error("<pre>$err</pre>");
 			}
 		else {
-			if ($in{'bond'}) {
+			if ($in{'bond'} && !&has_command("ip")) {
 				if (($gconfig{'os_type'} eq 'debian-linux') &&
 				    ($gconfig{'os_version'} >= 5)) {}
 				else {&load_module($b);}
@@ -389,4 +389,3 @@ else {
 		    "bifc", $b->{'fullname'}, $b);
 	}
 &redirect("list_ifcs.cgi?mode=boot");
-

net/t/run-tests.t

@@ -617,4 +617,47 @@ is_deeply(\@commands,
 	  [ "ip addr del 10\\.211\\.55\\.25\\/24 dev enp0s5 2>&1" ],
 	  "Linux active virtual interface is removed when saved down");
 
+@commands = ( );
+{
+	no warnings 'redefine';
+	no warnings 'once';
+	local *main::has_command = sub {
+		return $_[0] eq "ip" ? "/sbin/ip" :
+		       $_[0] eq "ifconfig" ? "/sbin/ifconfig" : undef;
+		};
+	local *main::active_interfaces = sub {
+		return ( );
+		};
+	local *main::backquote_command = sub {
+		return "";
+		};
+	main::activate_interface({ 'name' => 'bond0',
+				   'fullname' => 'bond0',
+				   'virtual' => '',
+				   'bond' => 1,
+				   'partner' => 'eth0 eth1',
+				   'mode' => '1',
+				   'primary' => 'eth0',
+				   'miimon' => '100',
+				   'updelay' => '200',
+				   'downdelay' => '200',
+				   'address' => '10.0.0.2',
+				   'netmask' => '255.255.255.0',
+				   'address6' => [ ],
+				   'netmask6' => [ ],
+				   'up' => 1 });
+	}
+is_deeply(\@commands,
+	  [ "ip link add bond0 type bond mode active\\-backup miimon 100 updelay 200 downdelay 200 2>&1",
+	    "ip link set dev eth0 down 2>&1",
+	    "ip link set dev eth0 master bond0 2>&1",
+	    "ip link set dev eth0 up 2>&1",
+	    "ip link set dev eth1 down 2>&1",
+	    "ip link set dev eth1 master bond0 2>&1",
+	    "ip link set dev eth1 up 2>&1",
+	    "ip link set dev bond0 type bond primary eth0 2>&1",
+	    "ip link set dev bond0 up 2>&1",
+	    "cd / ; ip addr add 10\\.0\\.0\\.2/24 dev bond0 2>&1" ],
+	  "Linux active bond interface is created before assigning an address");
+
 done_testing();