w1_netlink.c

Go to the documentation of this file.

/*
 * w1_netlink.c
 *
 * Copyright (c) 2003 Evgeniy Polyakov <[email protected]>
 *
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */

#include <linux/slab.h>
#include <linux/skbuff.h>
#include <linux/netlink.h>
#include <linux/connector.h>

#include "w1.h"
#include "w1_log.h"
#include "w1_netlink.h"

#if defined(CONFIG_W1_CON) && (defined(CONFIG_CONNECTOR) || (defined(CONFIG_CONNECTOR_MODULE) && defined(CONFIG_W1_MODULE)))
void w1_netlink_send(struct w1_master *dev, struct w1_netlink_msg *msg)
{
    char buf[sizeof(struct cn_msg) + sizeof(struct w1_netlink_msg)];
    struct cn_msg *m = (struct cn_msg *)buf;
    struct w1_netlink_msg *w = (struct w1_netlink_msg *)(m+1);

    memset(buf, 0, sizeof(buf));

    m->id.idx = CN_W1_IDX;
    m->id.val = CN_W1_VAL;

    m->seq = dev->seq++;
    m->len = sizeof(struct w1_netlink_msg);

    memcpy(w, msg, sizeof(struct w1_netlink_msg));

    cn_netlink_send(m, 0, GFP_KERNEL);
}

static void w1_send_slave(struct w1_master *dev, u64 rn)
{
    struct cn_msg *msg = dev->priv;
    struct w1_netlink_msg *hdr = (struct w1_netlink_msg *)(msg + 1);
    struct w1_netlink_cmd *cmd = (struct w1_netlink_cmd *)(hdr + 1);
    int avail;

    /* update kernel slave list */
    w1_slave_found(dev, rn);

    avail = dev->priv_size - cmd->len;

    if (avail > 8) {
        u64 *data = (void *)(cmd + 1) + cmd->len;

        *data = rn;
        cmd->len += 8;
        hdr->len += 8;
        msg->len += 8;
        return;
    }

    msg->ack++;
    cn_netlink_send(msg, 0, GFP_KERNEL);

    msg->len = sizeof(struct w1_netlink_msg) + sizeof(struct w1_netlink_cmd);
    hdr->len = sizeof(struct w1_netlink_cmd);
    cmd->len = 0;
}

static int w1_process_search_command(struct w1_master *dev, struct cn_msg *msg,
        unsigned int avail)
{
    struct w1_netlink_msg *hdr = (struct w1_netlink_msg *)(msg + 1);
    struct w1_netlink_cmd *cmd = (struct w1_netlink_cmd *)(hdr + 1);
    int search_type = (cmd->cmd == W1_CMD_ALARM_SEARCH)?W1_ALARM_SEARCH:W1_SEARCH;

    dev->priv = msg;
    dev->priv_size = avail;

    w1_search_process_cb(dev, search_type, w1_send_slave);

    msg->ack = 0;
    cn_netlink_send(msg, 0, GFP_KERNEL);

    dev->priv = NULL;
    dev->priv_size = 0;

    return 0;
}

static int w1_send_read_reply(struct cn_msg *msg, struct w1_netlink_msg *hdr,
        struct w1_netlink_cmd *cmd)
{
    void *data;
    struct w1_netlink_msg *h;
    struct w1_netlink_cmd *c;
    struct cn_msg *cm;
    int err;

    data = kzalloc(sizeof(struct cn_msg) +
            sizeof(struct w1_netlink_msg) +
            sizeof(struct w1_netlink_cmd) +
            cmd->len, GFP_KERNEL);
    if (!data)
        return -ENOMEM;

    cm = (struct cn_msg *)(data);
    h = (struct w1_netlink_msg *)(cm + 1);
    c = (struct w1_netlink_cmd *)(h + 1);

    memcpy(cm, msg, sizeof(struct cn_msg));
    memcpy(h, hdr, sizeof(struct w1_netlink_msg));
    memcpy(c, cmd, sizeof(struct w1_netlink_cmd));

    cm->ack = msg->seq+1;
    cm->len = sizeof(struct w1_netlink_msg) +
        sizeof(struct w1_netlink_cmd) + cmd->len;

    h->len = sizeof(struct w1_netlink_cmd) + cmd->len;

    memcpy(c->data, cmd->data, c->len);

    err = cn_netlink_send(cm, 0, GFP_KERNEL);

    kfree(data);

    return err;
}

static int w1_process_command_io(struct w1_master *dev, struct cn_msg *msg,
        struct w1_netlink_msg *hdr, struct w1_netlink_cmd *cmd)
{
    int err = 0;

    switch (cmd->cmd) {
    case W1_CMD_TOUCH:
        w1_touch_block(dev, cmd->data, cmd->len);
        w1_send_read_reply(msg, hdr, cmd);
        break;
    case W1_CMD_READ:
        w1_read_block(dev, cmd->data, cmd->len);
        w1_send_read_reply(msg, hdr, cmd);
        break;
    case W1_CMD_WRITE:
        w1_write_block(dev, cmd->data, cmd->len);
        break;
    default:
        err = -EINVAL;
        break;
    }

    return err;
}

static int w1_process_command_master(struct w1_master *dev, struct cn_msg *req_msg,
        struct w1_netlink_msg *req_hdr, struct w1_netlink_cmd *req_cmd)
{
    int err = -EINVAL;
    struct cn_msg *msg;
    struct w1_netlink_msg *hdr;
    struct w1_netlink_cmd *cmd;

    msg = kzalloc(PAGE_SIZE, GFP_KERNEL);
    if (!msg)
        return -ENOMEM;

    msg->id = req_msg->id;
    msg->seq = req_msg->seq;
    msg->ack = 0;
    msg->len = sizeof(struct w1_netlink_msg) + sizeof(struct w1_netlink_cmd);

    hdr = (struct w1_netlink_msg *)(msg + 1);
    cmd = (struct w1_netlink_cmd *)(hdr + 1);

    hdr->type = W1_MASTER_CMD;
    hdr->id = req_hdr->id;
    hdr->len = sizeof(struct w1_netlink_cmd);

    cmd->cmd = req_cmd->cmd;
    cmd->len = 0;

    switch (cmd->cmd) {
    case W1_CMD_SEARCH:
    case W1_CMD_ALARM_SEARCH:
        err = w1_process_search_command(dev, msg,
                PAGE_SIZE - msg->len - sizeof(struct cn_msg));
        break;
    case W1_CMD_READ:
    case W1_CMD_WRITE:
    case W1_CMD_TOUCH:
        err = w1_process_command_io(dev, req_msg, req_hdr, req_cmd);
        break;
    case W1_CMD_RESET:
        err = w1_reset_bus(dev);
        break;
    default:
        err = -EINVAL;
        break;
    }

    kfree(msg);
    return err;
}

static int w1_process_command_slave(struct w1_slave *sl, struct cn_msg *msg,
        struct w1_netlink_msg *hdr, struct w1_netlink_cmd *cmd)
{
    dev_dbg(&sl->master->dev, "%s: %02x.%012llx.%02x: cmd=%02x, len=%u.\n",
        __func__, sl->reg_num.family, (unsigned long long)sl->reg_num.id,
        sl->reg_num.crc, cmd->cmd, cmd->len);

    return w1_process_command_io(sl->master, msg, hdr, cmd);
}

static int w1_process_command_root(struct cn_msg *msg, struct w1_netlink_msg *mcmd)
{
    struct w1_master *m;
    struct cn_msg *cn;
    struct w1_netlink_msg *w;
    u32 *id;

    if (mcmd->type != W1_LIST_MASTERS) {
        printk(KERN_NOTICE "%s: msg: %x.%x, wrong type: %u, len: %u.\n",
            __func__, msg->id.idx, msg->id.val, mcmd->type, mcmd->len);
        return -EPROTO;
    }

    cn = kmalloc(PAGE_SIZE, GFP_KERNEL);
    if (!cn)
        return -ENOMEM;

    cn->id.idx = CN_W1_IDX;
    cn->id.val = CN_W1_VAL;

    cn->seq = msg->seq;
    cn->ack = 1;
    cn->len = sizeof(struct w1_netlink_msg);
    w = (struct w1_netlink_msg *)(cn + 1);

    w->type = W1_LIST_MASTERS;
    w->status = 0;
    w->len = 0;
    id = (u32 *)(w + 1);

    mutex_lock(&w1_mlock);
    list_for_each_entry(m, &w1_masters, w1_master_entry) {
        if (cn->len + sizeof(*id) > PAGE_SIZE - sizeof(struct cn_msg)) {
            cn_netlink_send(cn, 0, GFP_KERNEL);
            cn->ack++;
            cn->len = sizeof(struct w1_netlink_msg);
            w->len = 0;
            id = (u32 *)(w + 1);
        }

        *id = m->id;
        w->len += sizeof(*id);
        cn->len += sizeof(*id);
        id++;
    }
    cn->ack = 0;
    cn_netlink_send(cn, 0, GFP_KERNEL);
    mutex_unlock(&w1_mlock);

    kfree(cn);
    return 0;
}

static int w1_netlink_send_error(struct cn_msg *rcmsg, struct w1_netlink_msg *rmsg,
        struct w1_netlink_cmd *rcmd, int error)
{
    struct cn_msg *cmsg;
    struct w1_netlink_msg *msg;
    struct w1_netlink_cmd *cmd;

    cmsg = kzalloc(sizeof(*msg) + sizeof(*cmd) + sizeof(*cmsg), GFP_KERNEL);
    if (!cmsg)
        return -ENOMEM;

    msg = (struct w1_netlink_msg *)(cmsg + 1);
    cmd = (struct w1_netlink_cmd *)(msg + 1);

    memcpy(cmsg, rcmsg, sizeof(*cmsg));
    cmsg->len = sizeof(*msg);

    memcpy(msg, rmsg, sizeof(*msg));
    msg->len = 0;
    msg->status = (short)-error;

    if (rcmd) {
        memcpy(cmd, rcmd, sizeof(*cmd));
        cmd->len = 0;
        msg->len += sizeof(*cmd);
        cmsg->len += sizeof(*cmd);
    }

    error = cn_netlink_send(cmsg, 0, GFP_KERNEL);
    kfree(cmsg);

    return error;
}

static void w1_cn_callback(struct cn_msg *msg, struct netlink_skb_parms *nsp)
{
    struct w1_netlink_msg *m = (struct w1_netlink_msg *)(msg + 1);
    struct w1_netlink_cmd *cmd;
    struct w1_slave *sl;
    struct w1_master *dev;
    int err = 0;

    while (msg->len && !err) {
        struct w1_reg_num id;
        u16 mlen = m->len;
        u8 *cmd_data = m->data;

        dev = NULL;
        sl = NULL;
        cmd = NULL;

        memcpy(&id, m->id.id, sizeof(id));
#if 0
        printk("%s: %02x.%012llx.%02x: type=%02x, len=%u.\n",
                __func__, id.family, (unsigned long long)id.id, id.crc, m->type, m->len);
#endif
        if (m->len + sizeof(struct w1_netlink_msg) > msg->len) {
            err = -E2BIG;
            break;
        }

        if (m->type == W1_MASTER_CMD) {
            dev = w1_search_master_id(m->id.mst.id);
        } else if (m->type == W1_SLAVE_CMD) {
            sl = w1_search_slave(&id);
            if (sl)
                dev = sl->master;
        } else {
            err = w1_process_command_root(msg, m);
            goto out_cont;
        }

        if (!dev) {
            err = -ENODEV;
            goto out_cont;
        }

        err = 0;
        if (!mlen)
            goto out_cont;

        mutex_lock(&dev->mutex);

        if (sl && w1_reset_select_slave(sl)) {
            err = -ENODEV;
            goto out_up;
        }

        while (mlen) {
            cmd = (struct w1_netlink_cmd *)cmd_data;

            if (cmd->len + sizeof(struct w1_netlink_cmd) > mlen) {
                err = -E2BIG;
                break;
            }

            if (sl)
                err = w1_process_command_slave(sl, msg, m, cmd);
            else
                err = w1_process_command_master(dev, msg, m, cmd);

            w1_netlink_send_error(msg, m, cmd, err);
            err = 0;

            cmd_data += cmd->len + sizeof(struct w1_netlink_cmd);
            mlen -= cmd->len + sizeof(struct w1_netlink_cmd);
        }
out_up:
        atomic_dec(&dev->refcnt);
        if (sl)
            atomic_dec(&sl->refcnt);
        mutex_unlock(&dev->mutex);
out_cont:
        if (!cmd || err)
            w1_netlink_send_error(msg, m, cmd, err);
        msg->len -= sizeof(struct w1_netlink_msg) + m->len;
        m = (struct w1_netlink_msg *)(((u8 *)m) + sizeof(struct w1_netlink_msg) + m->len);

        /*
         * Let's allow requests for nonexisting devices.
         */
        if (err == -ENODEV)
            err = 0;
    }
}

int w1_init_netlink(void)
{
    struct cb_id w1_id = {.idx = CN_W1_IDX, .val = CN_W1_VAL};

    return cn_add_callback(&w1_id, "w1", &w1_cn_callback);
}

void w1_fini_netlink(void)
{
    struct cb_id w1_id = {.idx = CN_W1_IDX, .val = CN_W1_VAL};

    cn_del_callback(&w1_id);
}
#else
void w1_netlink_send(struct w1_master *dev, struct w1_netlink_msg *msg)
{
}

int w1_init_netlink(void)
{
    return 0;
}

void w1_fini_netlink(void)
{
}
#endif