CA-120846: fix get_mac for bonded interfaces

When an interface is bonded by the Linux bonding driver, the driver may change
the MAC address of the interface to that of the bond. The only place where you
can find the "real" MAC address of a bond slave seems to be /proc/net/bonding.

Signed-off-by: Rob Hoes <[email protected]>

Author: robhoes

lib/network_utils.ml

@@ -445,6 +445,12 @@ module Linux_bonding = struct
 				error "Failed to remove slave %s from bond %s" slave master
 		else
 			error "Bond %s does not exist; cannot remove slave" master
+
+	let get_bond_master_of slave =
+		try
+			let path = Unix.readlink (Sysfs.getpath slave "master") in
+			Some (List.hd (List.rev (String.split '/' path)))
+		with _ -> None
 end
 
 module Dhclient = struct
@@ -533,28 +539,46 @@ module Sysctl = struct
 end
 
 module Proc = struct
-	let get_bond_links_up name = 
+	let get_bond_slave_info name key =
 		try
 			let raw = Unixext.string_of_file (bonding_dir ^ name) in
 			let lines = String.split '\n' raw in
 			let check_lines lines =
-			let rec loop acc = function
-				| [] -> acc
-				| line1 :: line2 :: tail ->
-					if (String.startswith "Slave Interface:" line1)
-						&& (String.startswith "MII Status:" line2)
-						&& (String.endswith "up" line2)
-					then
-						loop (acc + 1) tail
-					else
-						loop acc (line2 :: tail)
-			  | _ :: [] -> acc in
-			loop 0 lines in
+				let rec loop current acc = function
+					| [] -> acc
+					| line :: tail ->
+						try
+							Scanf.sscanf line "%s@: %s@\n" (fun k v ->
+								if k = "Slave Interface" then begin
+									let interface = Some (String.strip String.isspace v) in
+									loop interface acc tail
+								end else if k = key then
+									match current with
+									| Some interface -> loop current ((interface, String.strip String.isspace v) :: acc) tail
+									| None -> loop current acc tail
+								else
+									loop current acc tail
+							)
+						with _ ->
+							loop current acc tail
+				in
+				loop None [] lines
+			in
 			check_lines lines
 		with e ->
 			error "Error: could not read %s." (bonding_dir ^ name);
-			0
+			[]
 
+	let get_bond_slave_mac name slave =
+		let macs = get_bond_slave_info name "Permanent HW addr" in
+		if List.mem_assoc slave macs then
+			List.assoc slave macs
+		else
+			raise Not_found
+
+	let get_bond_links_up name =
+		let statusses = get_bond_slave_info name "MII Status" in
+		List.fold_left (fun x (_, y) -> x + (if y = "up" then 1 else 0)) 0 statusses
 end
 
 module Ovs = struct

networkd/network_server.ml

@@ -103,7 +103,9 @@ module Interface = struct
 
 	let get_mac _ dbg ~name =
 		Debug.with_thread_associated dbg (fun () ->
-			Ip.get_mac name
+			match Linux_bonding.get_bond_master_of name with
+			| Some master -> Proc.get_bond_slave_mac master name
+			| None -> Ip.get_mac name
 		) ()
 
 	let is_up _ dbg ~name =