netlink: Add functionality to copy addresses from outer namespace

Similarly to what we've just done with routes, support NL_DUP for
addresses (currently not exposed): nl_addr() can optionally copy
mulitple addresses to the target namespace, by fixing up data from
the dump with appropriate flags and interface index, and repeating
it back to the kernel on the socket opened in the target namespace.

Link-local addresses are not copied: the family is set to AF_UNSPEC,
which means the kernel will ignore them. Same for addresses from a
mismatching address (pre-4.19 kernels without support for
NETLINK_GET_STRICT_CHK).

Ignore IFA_LABEL attributes by changing their type to IFA_UNSPEC,
because in general they will report mismatching names, and we don't
really need to use labels as we already know the interface index.

Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>

1 files changed, 4 insertions, 4 deletions

diff --git a/pasta.c b/pasta.c
index c2fb1f4..798aeb6 100644
--- a/pasta.c
+++ b/pasta.c
@@ -278,16 +278,16 @@ void pasta_ns_conf(struct ctx *c)
 		nl_link(1, c->pasta_ifi, c->mac_guest, 1, c->mtu);
 
 		if (c->ifi4) {
-			nl_addr(1, c->pasta_ifi, AF_INET, &c->ip4.addr,
-				&c->ip4.prefix_len, NULL);
+			nl_addr(NL_SET, c->ifi4, c->pasta_ifi, AF_INET,
+				&c->ip4.addr, &c->ip4.prefix_len, NULL);
 			nl_route(op_routes, c->ifi4, c->pasta_ifi, AF_INET,
 				 &c->ip4.gw);
 		}
 
 		if (c->ifi6) {
 			int prefix_len = 64;
-			nl_addr(1, c->pasta_ifi, AF_INET6, &c->ip6.addr,
-				&prefix_len, NULL);
+			nl_addr(NL_SET, c->ifi6, c->pasta_ifi, AF_INET6,
+				&c->ip6.addr, &prefix_len, NULL);
 			nl_route(op_routes, c->ifi6, c->pasta_ifi, AF_INET6,
 				 &c->ip6.gw);
 		}