ospfv2: use ipi_spec_dst for the outgoing source address

On send, the kernel reads the source address from the ipi_spec_dst
field of in_pktinfo, not ipi_addr (which is only meaningful on
receive). Writing it to ipi_addr made the kernel choose the source
itself, which can differ from the address Holo selected when the
interface has multiple addresses.

Signed-off-by: Renato Westphal <renatowestphal@gmail.com>

Author: rwestphal

holo-ospf/src/ospfv2/network.rs

@@ -124,8 +124,10 @@ impl NetworkVersion<Self> for Ospfv2 {
     fn new_pktinfo(src: Ipv4Addr, ifindex: u32) -> libc::in_pktinfo {
         libc::in_pktinfo {
             ipi_ifindex: ifindex as i32,
-            ipi_spec_dst: libc::in_addr { s_addr: 0 },
-            ipi_addr: libc::in_addr { s_addr: src.into() },
+            ipi_spec_dst: libc::in_addr {
+                s_addr: u32::from_ne_bytes(src.octets()),
+            },
+            ipi_addr: libc::in_addr { s_addr: 0 },
         }
     }