mptcp: implement mptcp_userspace_pm_dump_addr

This patch implements mptcp_userspace_pm_dump_addr() to dump addresses
from userspace pm address list. Use mptcp_token_get_sock() to get the
msk from the given token, if userspace PM is enabled in it, traverse
each address entry in address list, put every entry to userspace using
mptcp_pm_nl_put_entry_msg().
Signed-off-by: Geliang Tang <tanggeliang@kylinos.cn>
Reviewed-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/mptcp/pm_userspace.c

@@ -572,3 +572,63 @@ int mptcp_userspace_pm_set_flags(struct net *net, struct nlattr *token,
 	sock_put(sk);
 	return ret;
 }
+
+int mptcp_userspace_pm_dump_addr(struct sk_buff *msg,
+				 struct netlink_callback *cb)
+{
+	struct id_bitmap {
+		DECLARE_BITMAP(map, MPTCP_PM_MAX_ADDR_ID + 1);
+	} *bitmap;
+	const struct genl_info *info = genl_info_dump(cb);
+	struct net *net = sock_net(msg->sk);
+	struct mptcp_pm_addr_entry *entry;
+	struct mptcp_sock *msk;
+	struct nlattr *token;
+	int ret = -EINVAL;
+	struct sock *sk;
+	void *hdr;
+
+	bitmap = (struct id_bitmap *)cb->ctx;
+	token = info->attrs[MPTCP_PM_ATTR_TOKEN];
+
+	msk = mptcp_token_get_sock(net, nla_get_u32(token));
+	if (!msk) {
+		NL_SET_ERR_MSG_ATTR(info->extack, token, "invalid token");
+		return ret;
+	}
+
+	sk = (struct sock *)msk;
+
+	if (!mptcp_pm_is_userspace(msk)) {
+		GENL_SET_ERR_MSG(info, "invalid request; userspace PM not selected");
+		goto out;
+	}
+
+	lock_sock(sk);
+	spin_lock_bh(&msk->pm.lock);
+	list_for_each_entry(entry, &msk->pm.userspace_pm_local_addr_list, list) {
+		if (test_bit(entry->addr.id, bitmap->map))
+			continue;
+
+		hdr = genlmsg_put(msg, NETLINK_CB(cb->skb).portid,
+				  cb->nlh->nlmsg_seq, &mptcp_genl_family,
+				  NLM_F_MULTI, MPTCP_PM_CMD_GET_ADDR);
+		if (!hdr)
+			break;
+
+		if (mptcp_nl_fill_addr(msg, entry) < 0) {
+			genlmsg_cancel(msg, hdr);
+			break;
+		}
+
+		__set_bit(entry->addr.id, bitmap->map);
+		genlmsg_end(msg, hdr);
+	}
+	spin_unlock_bh(&msk->pm.lock);
+	release_sock(sk);
+	ret = msg->len;
+
+out:
+	sock_put(sk);
+	return ret;
+}

net/mptcp/protocol.h

@@ -1064,6 +1064,8 @@ bool mptcp_pm_rm_addr_signal(struct mptcp_sock *msk, unsigned int remaining,
 int mptcp_pm_get_local_id(struct mptcp_sock *msk, struct sock_common *skc);
 int mptcp_pm_nl_get_local_id(struct mptcp_sock *msk, struct mptcp_addr_info *skc);
 int mptcp_userspace_pm_get_local_id(struct mptcp_sock *msk, struct mptcp_addr_info *skc);
+int mptcp_userspace_pm_dump_addr(struct sk_buff *msg,
+				 struct netlink_callback *cb);
 
 static inline u8 subflow_get_local_id(const struct mptcp_subflow_context *subflow)
 {