+struct if_get_master_data {
+ int ifindex;
+ int master_ifindex;
+ int pending;
+};
+
+static void if_get_master_dsa_linkinfo_attr(struct if_get_master_data *data,
+ struct rtattr *attr)
+{
+ struct rtattr *cur;
+ int rem = RTA_PAYLOAD(attr);
+
+ for (cur = RTA_DATA(attr); RTA_OK(cur, rem); cur = RTA_NEXT(cur, rem)) {
+ if (cur->rta_type != IFLA_DSA_MASTER)
+ continue;
+
+ data->master_ifindex = *(__u32 *)RTA_DATA(cur);
+ }
+}
+
+static void if_get_master_linkinfo_attr(struct if_get_master_data *data,
+ struct rtattr *attr)
+{
+ struct rtattr *cur;
+ int rem = RTA_PAYLOAD(attr);
+
+ for (cur = RTA_DATA(attr); RTA_OK(cur, rem); cur = RTA_NEXT(cur, rem)) {
+ if (cur->rta_type != IFLA_INFO_KIND && cur->rta_type != IFLA_INFO_DATA)
+ continue;
+
+ if (cur->rta_type == IFLA_INFO_KIND && strcmp("dsa", (char *)RTA_DATA(cur)))
+ break;
+
+ if (cur->rta_type == IFLA_INFO_DATA)
+ if_get_master_dsa_linkinfo_attr(data, cur);
+ }
+}
+
+static int cb_if_get_master_valid(struct nl_msg *msg, void *arg)
+{
+ struct nlmsghdr *nh = nlmsg_hdr(msg);
+ struct ifinfomsg *ifi = NLMSG_DATA(nh);
+ struct if_get_master_data *data = (struct if_get_master_data *)arg;
+ struct rtattr *attr;
+ int rem;
+
+ if (nh->nlmsg_type != RTM_NEWLINK)
+ return NL_SKIP;
+
+ if (ifi->ifi_family != AF_UNSPEC)
+ return NL_SKIP;
+
+ if (ifi->ifi_index != data->ifindex)
+ return NL_SKIP;
+
+ attr = IFLA_RTA(ifi);
+ rem = nh->nlmsg_len - NLMSG_LENGTH(sizeof(*ifi));
+
+ while (RTA_OK(attr, rem)) {
+ if (attr->rta_type == IFLA_LINKINFO)
+ if_get_master_linkinfo_attr(data, attr);
+
+ attr = RTA_NEXT(attr, rem);
+ }
+
+ return NL_OK;
+}
+
+static int cb_if_get_master_ack(struct nl_msg *msg, void *arg)
+{
+ struct if_get_master_data *data = (struct if_get_master_data *)arg;
+ data->pending = 0;
+ return NL_STOP;
+}
+
+static int cb_if_get_master_error(struct sockaddr_nl *nla, struct nlmsgerr *err, void *arg)
+{
+ struct if_get_master_data *data = (struct if_get_master_data *)arg;
+ data->pending = 0;
+ return NL_STOP;
+}
+
+int system_if_get_master_ifindex(struct device *dev)
+{
+ struct nl_cb *cb = nl_cb_alloc(NL_CB_DEFAULT);
+ struct nl_msg *msg;
+ struct ifinfomsg ifi = {
+ .ifi_family = AF_UNSPEC,
+ .ifi_index = 0,
+ };
+ struct if_get_master_data data = {
+ .ifindex = if_nametoindex(dev->ifname),
+ .master_ifindex = -1,
+ .pending = 1,
+ };
+ int ret = -1;
+
+ if (!cb)
+ return ret;
+
+ msg = nlmsg_alloc_simple(RTM_GETLINK, NLM_F_REQUEST);
+ if (!msg)
+ goto out;
+
+ if (nlmsg_append(msg, &ifi, sizeof(ifi), 0) ||
+ nla_put_string(msg, IFLA_IFNAME, dev->ifname))
+ goto free;
+
+ nl_cb_set(cb, NL_CB_VALID, NL_CB_CUSTOM, cb_if_get_master_valid, &data);
+ nl_cb_set(cb, NL_CB_ACK, NL_CB_CUSTOM, cb_if_get_master_ack, &data);
+ nl_cb_err(cb, NL_CB_CUSTOM, cb_if_get_master_error, &data);
+
+ ret = nl_send_auto_complete(sock_rtnl, msg);
+ if (ret < 0)
+ goto free;
+
+ while (data.pending > 0)
+ nl_recvmsgs(sock_rtnl, cb);
+
+ if (data.master_ifindex >= 0)
+ ret = data.master_ifindex;
+
+free:
+ nlmsg_free(msg);
+out:
+ nl_cb_put(cb);
+ return ret;
+}
+
+static void system_set_master(struct device *dev, int master_ifindex)
+{
+ struct ifinfomsg ifi = { .ifi_family = AF_UNSPEC, };
+ struct nl_msg *nlm;
+
+ nlm = nlmsg_alloc_simple(RTM_NEWLINK, NLM_F_REQUEST);
+ if (!nlm)
+ return;
+
+ nlmsg_append(nlm, &ifi, sizeof(ifi), 0);
+ nla_put_string(nlm, IFLA_IFNAME, dev->ifname);
+
+ struct nlattr *linkinfo = nla_nest_start(nlm, IFLA_LINKINFO);
+ if (!linkinfo)
+ goto failure;
+
+ nla_put_string(nlm, IFLA_INFO_KIND, "dsa");
+ struct nlattr *infodata = nla_nest_start(nlm, IFLA_INFO_DATA);
+ if (!infodata)
+ goto failure;
+
+ nla_put_u32(nlm, IFLA_DSA_MASTER, master_ifindex);
+
+ nla_nest_end(nlm, infodata);
+ nla_nest_end(nlm, linkinfo);
+
+ system_rtnl_call(nlm);
+
+ return;
+
+failure:
+ nlmsg_free(nlm);
+}
+