...not just for a single set address (legacy operation with
--no-copy-addrs). I forgot to add this to nl_addr_dup().
Note that we can have two version of flags: the 8-bit ifa_flags in
ifaddrmsg, and the newer 32-bit version as IFA_FLAGS attribute, which
is given priority if present. Make sure IFA_F_NODAD is set in both.
Without this, a Podman user reports, something on the lines of:
pasta --config-net -- ping -c1 -6 passt.top
would fail as the kernel would start Duplicate Address Detection
once we configure the address, which can't really work (and doesn't
make sense) in this case.
Signed-off-by: Stefano Brivio <sbrivio(a)redhat.com>
---
netlink.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/netlink.c b/netlink.c
index 447fea2..b3897e6 100644
--- a/netlink.c
+++ b/netlink.c
@@ -804,6 +804,8 @@ int nl_addr_dup(int s_src, unsigned int ifi_src,
continue;
ifa->ifa_index = ifi_dst;
+ /* Same as nl_addr_set(), but here it's more than a default */
+ ifa->ifa_flags |= IFA_F_NODAD;
for (rta = IFA_RTA(ifa), na = IFA_PAYLOAD(nh); RTA_OK(rta, na);
rta = RTA_NEXT(rta, na)) {
@@ -811,6 +813,10 @@ int nl_addr_dup(int s_src, unsigned int ifi_src,
if (rta->rta_type == IFA_LABEL ||
rta->rta_type == IFA_CACHEINFO)
rta->rta_type = IFA_UNSPEC;
+
+ /* If 32-bit flags are used, add IFA_F_NODAD there */
+ if (rta->rta_type == IFA_FLAGS)
+ *(uint32_t *)RTA_DATA(rta) |= IFA_F_NODAD;
}
rc = nl_do(s_dst, nh, RTM_NEWADDR,
--
2.43.0