Add support for bonding / LAGs.

* Add a bond executor
  * Add mappings from ifupdown1/2
  * Add a detailed man page
  * Remove legacy compatiblity glue for setups with 'requires' only

  The current implementation has to work around the fact that member interfaces
  will be already up then the bond is created. This is simply done by downing
  them, adding them to the bundle and upping them again. This can possible be
  done in a nicer way after revisiting the ordering of plugin execution (#12).

  Closes #91

Signed-off-by: Maximilian Wilhelm <max@sdn.clinic>

Makefile

@@ -143,7 +143,8 @@ MANPAGES_8 = \
 	doc/ifctrstat.8
 
 MANPAGES_5 = \
-	doc/interfaces.5
+	doc/interfaces.5 \
+	doc/interfaces-bond.5
 
 MANPAGES_7 = \
 	doc/ifupdown-executor.7

doc/interfaces-bond.scd

@@ -0,0 +1,204 @@
+interfaces-bond(5)
+
+# NAME
+
+*interfaces-bond* - Bonding/LAG extensions for the interfaces(5) file format
+
+# DESCRIPTION
+
+The Linux implementation for Ling Aggregation Groups (LAGs) is called
+_bonding_, whereas a LAG interface is called _bond_. The Linux bonding
+implementation supports active/passive setups, classical EtherChannels
+as well as LACP (802.3ad).
+
+The following options set up bonding/LAG interfaces with ifupdown-ng.
+
+See https://www.kernel.org/doc/Documentation/networking/bonding.rst and
+for more information.
+
+# BOND-RELATED OPTIONS
+
+A bond interface must have at least one member port set. All other
+options are optional.
+
+*bond-members* _list of interfaces_
+	Denotes the physical member interfaces to form this LAG. For
+	compatiblity to ifupdown1 and ifupdown2 _slaves_ as well as
+	_bond-slaves_ are an alias for this option. This option is
+	required.
+
+*bond-mode* _mode_
+	Denotes the mode for this LAG. The _mode_ can be given as string
+	or as numerical value. Valid values are _balance-rr_ (0),
+	_active-backup_ (1), _balance-xor_ (2), _broadcast_ (3),
+	_802.3ad_ (4), _balance-tlb_ (5), _balance-alb_ (6).
+	The default is _balance-rr_.
+
+*bond-xmit-hash-policy* _policy_
+	Denotes the hash policy/algorithm used to distribute packets
+	across the physical links. This only applies for modes
+	_balance-alb_, _balance-tlb_, _balance-xor_, and _802.3ad_.
+	The _policy_ can be given as string or as numerical value.
+	Valid values are _layer2_ (0), _layer3+4_ (1), _layer2+3_ (2),
+	_encap2+3_ (3), and _encap3+4_ (4). The default is _layer2_.
+
+*bond-min-links* _number_
+	Denotes the minimum number of available links before turning on
+	carrier.
+
+*bond-miimon* _interval_
+	Denotes the MII link monitoring frequency in milliseconds.
+	This determines how often the link state of each slave is
+	inspected for link failures. A value of zero disables MII
+	link monitoring. The default is 0.
+
+*bond-use-carrier* _bool_
+	Denotes wether miimon uses MII or ethtool ioctls vs. the
+	netif_carrier_ok() call to determine member link status.
+	A value of 1 enables the use of netif_carrier_ok(), a value of
+	0 will use the deprecated MII / ETHTOOL ioctls. The default
+	is 1.
+
+*bond-updelay* _delay_
+	Denotes the delay in milliseconds before considering link up,
+	in milliseconds. The default is 0.
+
+*bond-downdelay* _delay_
+	Denotes the delay in milliseconds before considering link down,
+	in milliseconds. The default is 0.
+
+*bond-all-slaves-active* _bool_
+	Denotes wether duplicate frames (received on inactive ports)
+	should be dropped (0) or delivered (1). The default is 0.
+
+*bond-packets-per-slave* _num_packets_
+	Denotes the number of packets to transmit through a member
+	before moving to the next one. When set to 0 then a slave is
+	chosen at random. The valid range is 0 - 65535; the default
+	value is 1. This option has effect only in balance-rr mode.
+
+*bond-lp-interval* _interval_
+	Denotes the interval in seconds between sending learning packets
+	to each members peer switch. The valid range is 1 - 0x7fffffff;
+	the default value is 1. This option has effect only in modes
+	balance-tlb and balance-alb.
+
+*bond-resend-igmp* _number_
+	Denotes the number of IGMP membership reports to send after a
+	link failover happend. The valid range is 0 - 255; a value of
+	0 prevents the IGMP membership report from being issued in
+	response to the failover event. The default is 1.
+	This option is useful for bonding modes balance-rr, active-backup
+	balance-tlb and balance-alb, in which a failover can switch the
+	IGMP traffic from one slave to another.
+
+# LACP-RELATED OPTIONS
+
+The following options are only valid in LACP (802.3ad) mode.
+
+*bond-lacp-rate* _rate_
+	Denotes the _rate_ of LACPDU requested from the peer. The _rate_
+	can be given as string or as numerical value. Valid values are
+	slow (0) and fast (1). The default is slow.
+
+*bond-ad-select* _mode_
+	Denotes the 802.3ad aggregation selection logic. The _mode_ can
+	be given as string or as numerical value. Valid values are
+	_stable_ (0), _bandwidth_ (1) and _cound_ (2). The default is
+	_stable_.
+
+*bond-ad-actor-sys-prio* _priority_
+	Denotes the LACP system priority. The allowed range is 1 - 65535.
+	The default value is 65535.
+
+*bond-ad-user-port-key* _key_
+	Denotes the upper 10 bits of the port-key. he values can be from
+	0 - 1023. The default is 0.
+
+
+# ACTIVE/BACKUP-RELATED OPTIONS
+
+The following options are only valid in active/passive setups.
+
+*bond-primary* _interface_
+	Denotes the primary member interface The specified device will
+	always be the active slave while it is available. The primary
+	option is only valid for active-backup, balance-tlb and
+	balance-alb mode.
+
+*bond-primary-reselect* _policy_
+	Denotes the reselection policy for the primary member interface.
+	Valid values are _always_ (0), _better_ (1), and _failure_ (2).
+	The default is _always_.
+
+*bond-fail-over-mac* _mode_
+	Denotes whether active-backup mode should set all member
+	interfaces to the same MAC address at enslavement (the
+	traditional behavior), or, when enabled, perform special
+	handling of the bond's MAC address in accordance with the
+	selected policy. Valid values are _none_ (0), _active_ (1),
+	_follow_ (2). The default is _none_.
+
+*bond-num-grat-arp* _count_
+	Denotes the number of peer notifications (gratuitous ARPs and
+	unsolicited IPv6 Neighbor Advertisements) to be issued after a
+	failover event. The valid range is 0 - 255; the default is 1.
+
+*bond-num-unsol-na* _count_
+	This is an alias for _bond-num-grat-arp_
+
+*bond-peer-notif-delay* _interval_
+	Denotes the interval in milliseconds, between each peer
+	notification (gratuitous ARP and unsolicited IPv6 Neighbor
+	Advertisement) issued after a failover event. The default
+	is 0 which means to match the value of the link monitor
+	interval.
+
+# ARP-RELATED OPTIONS
+
+The following options configure ARP link monitoring.
+The ARP monitor works by periodically checking the slave
+devices to determine whether they have sent or received
+traffic recently. Regular traffic is generated via ARP
+probes issued for the addresses specified by the
+_bond-arp-ip-target_ option.
+
+*bond-arp-interval* _interval_
+	Denotes the frequency in milliseconds to send ARP probes.
+
+*bond-arp-ip-target* _IPv4 address_
+	Denotes the IP addresses to use as ARP monitoring peers when
+	_bond-arp-interval_ is > 0.
+
+*bond-arp-validate* _mode_
+	Specifies whether or not ARP probes and replies should be
+	validated in any mode that supports arp monitoring, or whether
+	non-ARP traffic should be filtered (disregarded) for link
+	monitoring purposes. Valid values are _none_ (0), _active_ (1),
+	_backup_ (2), _all_ (3), _filter_ (4), _filter_active_ (5), and
+	_filter_backup_ (6). The default is _none_.
+
+*bond-arp-all-targets* _mode_
+	Denotes the number of _bond-arp-ip-targets_ that have to be
+	reachable to consider the member interface to be up. Valid
+	options are _any_ (0) and _all_ (1). The default is _any_.
+
+# EXAMPLES
+
+A bond using two links and LACP (802.3ad):
+
+```
+auto bond0
+iface bond0
+	bond-members eth0 eth1
+	bond-mode 802.3ad
+	bond-xmit-hash-policy layer3+4
+	bond-min-links 1
+	#
+	address 192.0.2.42/24
+	address 2001:db8::42/64
+```
+
+# AUTHORS
+
+Maximilian Wilhelm <max@sdn.clinic>

doc/interfaces.scd

@@ -180,6 +180,7 @@ iface eth0
 
 # SEE ALSO
 
+*interfaces-bond*(5)
 *interfaces-vxlan*(5)
 
 # AUTHORS

executor-scripts/linux/bond

@@ -0,0 +1,64 @@
+#!/bin/sh
+#
+# This executor is responsible for setting up bond/LAG interfaces.
+#
+# Sat, 03 Oct 2020 20:42:19 +0200
+#  -- Maximilian Wilhelm <max@sdn.clinic>
+#
+
+set -e
+
+[ -n "$VERBOSE" ] && set -x
+
+get_bond_options() {
+	env | while IFS="=" read opt value; do
+		# We only care for options of format IF_BOND_<OPTION_NAME>
+		if ! echo "${opt}" | grep -q '^IF_BOND_[A-Z0-9_]\+$'; then
+			continue
+		fi
+
+		# Members are handled seperately
+		if [ "${opt}" = "IF_BOND_MEMBERS" ]; then
+			continue
+		fi
+
+		# Convert options for the actual name
+		real_opt=$(echo "${opt}" | sed -e 's/^IF_BOND_\([A-Z0-9_]\+\)/\1/' | tr '[A-Z]' '[a-z]')
+
+		echo -n " ${real_opt} ${value}"
+	done
+}
+
+case "$PHASE" in
+	depend)
+		echo "${IF_BOND_MEMBERS}"
+		;;
+
+	create)
+		if [ -d "/sys/class/net/${IFACE}" ]; then
+			exit 0
+		fi
+
+		# Gather bonding options for this interface
+		options=$(get_bond_options)
+
+		# Create bond
+		${MOCK} ip link add "${IFACE}" type bond ${options}
+
+		# Add members to bundle
+		for member_iface in ${IF_BOND_MEMBERS}; do
+			# Work around the current execution order
+			ip link set "${member_iface}" down
+			ip link set master "${IFACE}" "${member_iface}"
+			ip link set "${member_iface}" up
+		done
+		;;
+
+	destroy)
+		if [ -z "${MOCK}" -a ! -d "/sys/class/net/${IFACE}" ]; then
+			exit 0
+		fi
+
+		${MOCK} ip link del "${IFACE}"
+		;;
+esac

libifupdown/interface-file.c

@@ -28,6 +28,8 @@ struct remap_token {
 
 /* this list must be in alphabetical order for bsearch */
 static const struct remap_token tokens[] = {
+	{"bond-ad-sys-priority", "bond-ad-actor-sys-prio"}, /* ifupdown2 */
+	{"bond-slaves", "bond-members"},		/* legacy ifupdown, ifupdown2 */
 	{"driver-message-level", "ethtool-msglvl"},	/* Debian ethtool integration */
 	{"endpoint", "tunnel-remote"},			/* legacy ifupdown */
 	{"ethernet-autoneg", "ethtool-ethernet-autoneg"},	/* Debian ethtool integration */

libifupdown/lifecycle.c

@@ -163,9 +163,6 @@ build_environment(char **envp[], const struct lif_execute_opts *opts, const stru
 		{
 			if (iface->is_bridge)
 				lif_environment_push(envp, "IF_BRIDGE_PORTS", (const char *) entry->data);
-
-			if (iface->is_bond)
-				lif_environment_push(envp, "IF_BOND_SLAVES", (const char *) entry->data);
 		}
 
 		char envkey[4096] = "IF_";