// 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,
                                 const 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;
}

/* 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 },
};

static int
ethnl_set_channels_validate(struct ethnl_req_info *req_info,
                            struct genl_info *info)
{
        const struct ethtool_ops *ops = req_info->dev->ethtool_ops;

        return ops->get_channels && ops->set_channels ? 1 : -EOPNOTSUPP;
}

static int
ethnl_set_channels(struct ethnl_req_info *req_info, struct genl_info *info)
{
        unsigned int from_channel, old_total, i;
        bool mod = false, mod_combined = false;
        struct net_device *dev = req_info->dev;
        struct ethtool_channels channels = {};
        struct nlattr **tb = info->attrs;
        u32 err_attr;
        int ret;

        dev->ethtool_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;
        if (!mod)
                return 0;

        /* ensure new channel counts are within limits */
        if (channels.rx_count > channels.max_rx)
                err_attr = ETHTOOL_A_CHANNELS_RX_COUNT;
        else if (channels.tx_count > channels.max_tx)
                err_attr = ETHTOOL_A_CHANNELS_TX_COUNT;
        else if (channels.other_count > channels.max_other)
                err_attr = ETHTOOL_A_CHANNELS_OTHER_COUNT;
        else if (channels.combined_count > channels.max_combined)
                err_attr = ETHTOOL_A_CHANNELS_COMBINED_COUNT;
        else
                err_attr = 0;
        if (err_attr) {
                NL_SET_ERR_MSG_ATTR(info->extack, tb[err_attr],
                                    "requested channel count exceeds maximum");
                return -EINVAL;
        }

        /* ensure there is at least one RX and one TX channel */
        if (!channels.combined_count && !channels.rx_count)
                err_attr = ETHTOOL_A_CHANNELS_RX_COUNT;
        else if (!channels.combined_count && !channels.tx_count)
                err_attr = ETHTOOL_A_CHANNELS_TX_COUNT;
        else
                err_attr = 0;
        if (err_attr) {
                if (mod_combined)
                        err_attr = ETHTOOL_A_CHANNELS_COMBINED_COUNT;
                NL_SET_ERR_MSG_ATTR(info->extack, tb[err_attr],
                                    "requested channel counts would result in no RX or TX channel being configured");
                return -EINVAL;
        }

        ret = ethtool_check_max_channel(dev, channels, info);
        if (ret)
                return ret;

        /* 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)) {
                        GENL_SET_ERR_MSG(info, "requested channel counts are too low for existing zerocopy AF_XDP sockets");
                        return -EINVAL;
                }

        ret = dev->ethtool_ops->set_channels(dev, &channels);
        return ret < 0 ? ret : 1;
}

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,

        .set_validate           = ethnl_set_channels_validate,
        .set                    = ethnl_set_channels,
        .set_ntf_cmd            = ETHTOOL_MSG_CHANNELS_NTF,
};