// SPDX-License-Identifier: GPL-2.0-only

  #include <net/xdp_sock_drv.h>

  #include "netlink.h"
  #include "common.h"
  
  struct channels_req_info {
  	struct ethnl_req_info		base;
  };
  
  struct channels_reply_data {
  	struct ethnl_reply_data		base;
  	struct ethtool_channels		channels;
  };
  
  #define CHANNELS_REPDATA(__reply_base) \
  	container_of(__reply_base, struct channels_reply_data, base)

  const struct nla_policy ethnl_channels_get_policy[] = {

  	[ETHTOOL_A_CHANNELS_HEADER]		=
  		NLA_POLICY_NESTED(ethnl_header_policy),

  };
  
  static int channels_prepare_data(const struct ethnl_req_info *req_base,
  				 struct ethnl_reply_data *reply_base,
  				 struct genl_info *info)
  {
  	struct channels_reply_data *data = CHANNELS_REPDATA(reply_base);
  	struct net_device *dev = reply_base->dev;
  	int ret;
  
  	if (!dev->ethtool_ops->get_channels)
  		return -EOPNOTSUPP;
  	ret = ethnl_ops_begin(dev);
  	if (ret < 0)
  		return ret;
  	dev->ethtool_ops->get_channels(dev, &data->channels);
  	ethnl_ops_complete(dev);
  
  	return 0;
  }
  
  static int channels_reply_size(const struct ethnl_req_info *req_base,
  			       const struct ethnl_reply_data *reply_base)
  {
  	return nla_total_size(sizeof(u32)) +	/* _CHANNELS_RX_MAX */
  	       nla_total_size(sizeof(u32)) +	/* _CHANNELS_TX_MAX */
  	       nla_total_size(sizeof(u32)) +	/* _CHANNELS_OTHER_MAX */
  	       nla_total_size(sizeof(u32)) +	/* _CHANNELS_COMBINED_MAX */
  	       nla_total_size(sizeof(u32)) +	/* _CHANNELS_RX_COUNT */
  	       nla_total_size(sizeof(u32)) +	/* _CHANNELS_TX_COUNT */
  	       nla_total_size(sizeof(u32)) +	/* _CHANNELS_OTHER_COUNT */
  	       nla_total_size(sizeof(u32));	/* _CHANNELS_COMBINED_COUNT */
  }
  
  static int channels_fill_reply(struct sk_buff *skb,
  			       const struct ethnl_req_info *req_base,
  			       const struct ethnl_reply_data *reply_base)
  {
  	const struct channels_reply_data *data = CHANNELS_REPDATA(reply_base);
  	const struct ethtool_channels *channels = &data->channels;
  
  	if ((channels->max_rx &&
  	     (nla_put_u32(skb, ETHTOOL_A_CHANNELS_RX_MAX,
  			  channels->max_rx) ||
  	      nla_put_u32(skb, ETHTOOL_A_CHANNELS_RX_COUNT,
  			  channels->rx_count))) ||
  	    (channels->max_tx &&
  	     (nla_put_u32(skb, ETHTOOL_A_CHANNELS_TX_MAX,
  			  channels->max_tx) ||
  	      nla_put_u32(skb, ETHTOOL_A_CHANNELS_TX_COUNT,
  			  channels->tx_count))) ||
  	    (channels->max_other &&
  	     (nla_put_u32(skb, ETHTOOL_A_CHANNELS_OTHER_MAX,
  			  channels->max_other) ||
  	      nla_put_u32(skb, ETHTOOL_A_CHANNELS_OTHER_COUNT,
  			  channels->other_count))) ||
  	    (channels->max_combined &&
  	     (nla_put_u32(skb, ETHTOOL_A_CHANNELS_COMBINED_MAX,
  			  channels->max_combined) ||
  	      nla_put_u32(skb, ETHTOOL_A_CHANNELS_COMBINED_COUNT,
  			  channels->combined_count))))
  		return -EMSGSIZE;
  
  	return 0;
  }
  
  const struct ethnl_request_ops ethnl_channels_request_ops = {
  	.request_cmd		= ETHTOOL_MSG_CHANNELS_GET,
  	.reply_cmd		= ETHTOOL_MSG_CHANNELS_GET_REPLY,
  	.hdr_attr		= ETHTOOL_A_CHANNELS_HEADER,

  	.req_info_size		= sizeof(struct channels_req_info),
  	.reply_data_size	= sizeof(struct channels_reply_data),

  
  	.prepare_data		= channels_prepare_data,
  	.reply_size		= channels_reply_size,
  	.fill_reply		= channels_fill_reply,
  };

  
  /* CHANNELS_SET */

  const struct nla_policy ethnl_channels_set_policy[] = {

  	[ETHTOOL_A_CHANNELS_HEADER]		=
  		NLA_POLICY_NESTED(ethnl_header_policy),

  	[ETHTOOL_A_CHANNELS_RX_COUNT]		= { .type = NLA_U32 },
  	[ETHTOOL_A_CHANNELS_TX_COUNT]		= { .type = NLA_U32 },
  	[ETHTOOL_A_CHANNELS_OTHER_COUNT]	= { .type = NLA_U32 },
  	[ETHTOOL_A_CHANNELS_COMBINED_COUNT]	= { .type = NLA_U32 },
  };
  
  int ethnl_set_channels(struct sk_buff *skb, struct genl_info *info)
  {

  	unsigned int from_channel, old_total, i;

  	bool mod = false, mod_combined = false;

  	struct ethtool_channels channels = {};
  	struct ethnl_req_info req_info = {};

  	struct nlattr **tb = info->attrs;

  	const struct nlattr *err_attr;
  	const struct ethtool_ops *ops;
  	struct net_device *dev;
  	u32 max_rx_in_use = 0;

  	int ret;

  	ret = ethnl_parse_header_dev_get(&req_info,
  					 tb[ETHTOOL_A_CHANNELS_HEADER],
  					 genl_info_net(info), info->extack,
  					 true);
  	if (ret < 0)
  		return ret;
  	dev = req_info.dev;
  	ops = dev->ethtool_ops;
  	ret = -EOPNOTSUPP;
  	if (!ops->get_channels || !ops->set_channels)
  		goto out_dev;
  
  	rtnl_lock();
  	ret = ethnl_ops_begin(dev);
  	if (ret < 0)
  		goto out_rtnl;
  	ops->get_channels(dev, &channels);
  	old_total = channels.combined_count +
  		    max(channels.rx_count, channels.tx_count);
  
  	ethnl_update_u32(&channels.rx_count, tb[ETHTOOL_A_CHANNELS_RX_COUNT],
  			 &mod);
  	ethnl_update_u32(&channels.tx_count, tb[ETHTOOL_A_CHANNELS_TX_COUNT],
  			 &mod);
  	ethnl_update_u32(&channels.other_count,
  			 tb[ETHTOOL_A_CHANNELS_OTHER_COUNT], &mod);
  	ethnl_update_u32(&channels.combined_count,

  			 tb[ETHTOOL_A_CHANNELS_COMBINED_COUNT], &mod_combined);
  	mod |= mod_combined;

  	ret = 0;
  	if (!mod)
  		goto out_ops;
  
  	/* ensure new channel counts are within limits */
  	if (channels.rx_count > channels.max_rx)
  		err_attr = tb[ETHTOOL_A_CHANNELS_RX_COUNT];
  	else if (channels.tx_count > channels.max_tx)
  		err_attr = tb[ETHTOOL_A_CHANNELS_TX_COUNT];
  	else if (channels.other_count > channels.max_other)
  		err_attr = tb[ETHTOOL_A_CHANNELS_OTHER_COUNT];
  	else if (channels.combined_count > channels.max_combined)
  		err_attr = tb[ETHTOOL_A_CHANNELS_COMBINED_COUNT];
  	else
  		err_attr = NULL;
  	if (err_attr) {
  		ret = -EINVAL;
  		NL_SET_ERR_MSG_ATTR(info->extack, err_attr,

  				    "requested channel count exceeds maximum");

  		goto out_ops;
  	}

  	/* ensure there is at least one RX and one TX channel */
  	if (!channels.combined_count && !channels.rx_count)
  		err_attr = tb[ETHTOOL_A_CHANNELS_RX_COUNT];
  	else if (!channels.combined_count && !channels.tx_count)
  		err_attr = tb[ETHTOOL_A_CHANNELS_TX_COUNT];
  	else
  		err_attr = NULL;
  	if (err_attr) {
  		if (mod_combined)
  			err_attr = tb[ETHTOOL_A_CHANNELS_COMBINED_COUNT];
  		ret = -EINVAL;
  		NL_SET_ERR_MSG_ATTR(info->extack, err_attr, "requested channel counts would result in no RX or TX channel being configured");
  		goto out_ops;
  	}

  	/* ensure the new Rx count fits within the configured Rx flow
  	 * indirection table settings
  	 */
  	if (netif_is_rxfh_configured(dev) &&
  	    !ethtool_get_max_rxfh_channel(dev, &max_rx_in_use) &&
  	    (channels.combined_count + channels.rx_count) <= max_rx_in_use) {

  		ret = -EINVAL;

  		GENL_SET_ERR_MSG(info, "requested channel counts are too low for existing indirection table settings");

  		goto out_ops;

  	}
  
  	/* Disabling channels, query zero-copy AF_XDP sockets */
  	from_channel = channels.combined_count +
  		       min(channels.rx_count, channels.tx_count);
  	for (i = from_channel; i < old_total; i++)

  		if (xsk_get_pool_from_qid(dev, i)) {

  			ret = -EINVAL;

  			GENL_SET_ERR_MSG(info, "requested channel counts are too low for existing zerocopy AF_XDP sockets");

  			goto out_ops;

  		}
  
  	ret = dev->ethtool_ops->set_channels(dev, &channels);

  	if (ret < 0)
  		goto out_ops;
  	ethtool_notify(dev, ETHTOOL_MSG_CHANNELS_NTF, NULL);

  
  out_ops:
  	ethnl_ops_complete(dev);
  out_rtnl:
  	rtnl_unlock();
  out_dev:
  	dev_put(dev);
  	return ret;
  }