[MPTCP] Re: [MPTCP][PATCH v2 mptcp-next 3/6] mptcp: add set_flags command in PM netlink

[MPTCP] Re: [MPTCP][PATCH v2 mptcp-next 3/6] mptcp: add set_flags command in PM netlink

[Mat Martineau]

[-- Attachment #1: Type: text/plain, Size: 4261 bytes --]

On Tue, 8 Dec 2020, Geliang Tang wrote:

> This patch added a new command MPTCP_PM_CMD_SET_FLAGS in PM netlink:
>
> In mptcp_nl_cmd_set_flags, parse the input address, get the backup value
> according to whether the address's FLAG_BACKUP or FLAG_NOBACKUP flag is
> set from the user-space. Then check whether this address had been added
> in the local address list. If it had been, then call mptcp_nl_addr_backup
> to deal with this address.
>
> In mptcp_nl_addr_backup, traverse all the existing msk sockets to find
> the relevant sockets, and call mptcp_pm_nl_mp_prio_send_ack to send out
> a MP_PRIO ACK packet.
>
> Finally in mptcp_nl_cmd_set_flags, set or clear the address's FLAG_BACKUP
> flag.
>
> Signed-off-by: Geliang Tang <geliangtang(a)gmail.com>
> ---
> include/uapi/linux/mptcp.h |  2 ++
> net/mptcp/pm_netlink.c     | 67 ++++++++++++++++++++++++++++++++++++++
> 2 files changed, 69 insertions(+)
>
> diff --git a/include/uapi/linux/mptcp.h b/include/uapi/linux/mptcp.h
> index 9762660df741..5470da50f4ac 100644
> --- a/include/uapi/linux/mptcp.h
> +++ b/include/uapi/linux/mptcp.h
> @@ -72,6 +72,7 @@ enum {
> #define MPTCP_PM_ADDR_FLAG_SIGNAL			(1 << 0)
> #define MPTCP_PM_ADDR_FLAG_SUBFLOW			(1 << 1)
> #define MPTCP_PM_ADDR_FLAG_BACKUP			(1 << 2)
> +#define MPTCP_PM_ADDR_FLAG_NOBACKUP			(1 << 3)

Hi Geliang -

My understanding of Paolo's suggestion was that 'nobackup' is helpful for 
the 'ip mptcp' command line syntax, but I don't think that means a 
separate flag at the netlink level is needed.


Mat


>
> enum {
> 	MPTCP_PM_CMD_UNSPEC,
> @@ -82,6 +83,7 @@ enum {
> 	MPTCP_PM_CMD_FLUSH_ADDRS,
> 	MPTCP_PM_CMD_SET_LIMITS,
> 	MPTCP_PM_CMD_GET_LIMITS,
> +	MPTCP_PM_CMD_SET_FLAGS,
>
> 	__MPTCP_PM_CMD_AFTER_LAST
> };
> diff --git a/net/mptcp/pm_netlink.c b/net/mptcp/pm_netlink.c
> index fc61ca6dc04d..761cb5afa922 100644
> --- a/net/mptcp/pm_netlink.c
> +++ b/net/mptcp/pm_netlink.c
> @@ -1153,6 +1153,68 @@ mptcp_nl_cmd_get_limits(struct sk_buff *skb, struct genl_info *info)
> 	return -EMSGSIZE;
> }
>
> +static int mptcp_nl_addr_backup(struct net *net,
> +				struct mptcp_addr_info *addr,
> +				u8 bkup)
> +{
> +	long s_slot = 0, s_num = 0;
> +	struct mptcp_sock *msk;
> +	int ret = -EINVAL;
> +
> +	while ((msk = mptcp_token_iter_next(net, &s_slot, &s_num)) != NULL) {
> +		struct sock *sk = (struct sock *)msk;
> +
> +		if (list_empty(&msk->conn_list))
> +			goto next;
> +
> +		lock_sock(sk);
> +		spin_lock_bh(&msk->pm.lock);
> +		ret = mptcp_pm_nl_mp_prio_send_ack(msk, addr, bkup);
> +		spin_unlock_bh(&msk->pm.lock);
> +		release_sock(sk);
> +
> +next:
> +		sock_put(sk);
> +		cond_resched();
> +	}
> +
> +	return ret;
> +}
> +
> +static int mptcp_nl_cmd_set_flags(struct sk_buff *skb, struct genl_info *info)
> +{
> +	struct nlattr *attr = info->attrs[MPTCP_PM_ATTR_ADDR];
> +	struct pm_nl_pernet *pernet = genl_info_pm_nl(info);
> +	struct mptcp_pm_addr_entry addr, *entry;
> +	struct net *net = sock_net(skb->sk);
> +	u8 bkup;
> +	int ret;
> +
> +	ret = mptcp_pm_parse_addr(attr, info, true, &addr);
> +	if (ret < 0)
> +		return ret;
> +
> +	if (addr.addr.flags & MPTCP_PM_ADDR_FLAG_BACKUP)
> +		bkup = 1;
> +	else if (addr.addr.flags & MPTCP_PM_ADDR_FLAG_NOBACKUP)
> +		bkup = 0;
> +
> +	list_for_each_entry(entry, &pernet->local_addr_list, list) {
> +		if (addresses_equal(&entry->addr, &addr.addr, true)) {
> +			ret = mptcp_nl_addr_backup(net, &entry->addr, bkup);
> +			if (ret)
> +				return ret;
> +
> +			if (bkup)
> +				entry->addr.flags |= MPTCP_PM_ADDR_FLAG_BACKUP;
> +			else
> +				entry->addr.flags &= ~MPTCP_PM_ADDR_FLAG_BACKUP;
> +		}
> +	}
> +
> +	return 0;
> +}
> +
> static const struct genl_small_ops mptcp_pm_ops[] = {
> 	{
> 		.cmd    = MPTCP_PM_CMD_ADD_ADDR,
> @@ -1183,6 +1245,11 @@ static const struct genl_small_ops mptcp_pm_ops[] = {
> 		.cmd    = MPTCP_PM_CMD_GET_LIMITS,
> 		.doit   = mptcp_nl_cmd_get_limits,
> 	},
> +	{
> +		.cmd    = MPTCP_PM_CMD_SET_FLAGS,
> +		.doit   = mptcp_nl_cmd_set_flags,
> +		.flags  = GENL_ADMIN_PERM,
> +	},
> };
>
> static struct genl_family mptcp_genl_family __ro_after_init = {
> -- 
> 2.26.2

--
Mat Martineau
Intel