On Sat, 17 Aug 2024 10:37:16 +0200 Stefano Brivio <sbrivio(a)redhat.com> wrote:On Sat, 17 Aug 2024 17:59:45 +1000 David Gibson <david(a)gibson.dropbear.id.au> wrote:6/7, actually. -- StefanoOn Fri, Aug 16, 2024 at 09:39:15AM +0200, Stefano Brivio wrote:Worse :( I accidentally squashed the new changes into 5/7.It makes no sense for a container or a guest to try and perform duplicate address detection for their link-local address, as we'll anyway not relay neighbour solicitations with an unspecified source address. While they perform duplicate address detection, the link-local address is not usable, which prevents us from bringing up especially containers and communicate with them right away via IPv6. This is not enough to prevent DAD and reach the container right away: we'll need a couple more patches. As we send NLM_F_REPLACE requests right away, while we still have to read out other addresses on the same socket, we can't use nl_do(): keep track of the last sequence we sent (last address we changed), and deal with the answers to those NLM_F_REPLACE requests in a separate loop, later. Link: https://github.com/containers/podman/pull/23561#discussion_r1711639663 Signed-off-by: Stefano Brivio <sbrivio(a)redhat.com> --- netlink.c | 55 +++++++++++++++++++++++++++++++++++++++++++++++++++++++ netlink.h | 1 + pasta.c | 6 ++++++ 3 files changed, 62 insertions(+) diff --git a/netlink.c b/netlink.c index 873e6c7..59f2fd9 100644 --- a/netlink.c +++ b/netlink.c @@ -673,6 +673,61 @@ int nl_route_dup(int s_src, unsigned int ifi_src, return 0; } +/** + * nl_addr_set_ll_nodad() - Set IFA_F_NODAD on IPv6 link-local addresses + * @s: Netlink socket + * @ifi: Interface index in target namespace + * + * Return: 0 on success, negative error code on failure + */ +int nl_addr_set_ll_nodad(int s, unsigned int ifi) +{ + struct req_t { + struct nlmsghdr nlh; + struct ifaddrmsg ifa; + } req = { + .ifa.ifa_family = AF_INET6, + .ifa.ifa_index = ifi, + }; + unsigned ll_addrs = 0; + struct nlmsghdr *nh; + char buf[NLBUFSIZ]; + ssize_t status; + uint32_t seq; + + seq = nl_send(s, &req, RTM_GETADDR, NLM_F_DUMP, sizeof(req)); + nl_foreach_oftype(nh, status, s, buf, seq, RTM_NEWADDR) { + struct ifaddrmsg *ifa = (struct ifaddrmsg *)NLMSG_DATA(nh); + struct rtattr *rta; + size_t na; + + if (ifa->ifa_index != ifi || ifa->ifa_scope != RT_SCOPE_LINK) + continue; + + ifa->ifa_flags |= IFA_F_NODAD; + + for (rta = IFA_RTA(ifa), na = IFA_PAYLOAD(nh); RTA_OK(rta, na); + rta = RTA_NEXT(rta, na)) { + /* 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; + } + + nl_send(s, nh, RTM_NEWADDR, NLM_F_REPLACE, nh->nlmsg_len); + ll_addrs++; + }Uh.. did you forget to push an update. This looks like the last version.