[PATCH] uml: add locking to network transport registration

[linux-2.6/openmoko-kernel/knife-kernel.git] / arch / um / drivers / net_kern.c

/*
 * Copyright (C) 2001 Lennert Buytenhek (buytenh@gnu.org) and
 * James Leu (jleu@mindspring.net).
 * Copyright (C) 2001 by various other people who didn't put their name here.
 * Licensed under the GPL.
 */

#include "linux/kernel.h"
#include "linux/netdevice.h"
#include "linux/rtnetlink.h"
#include "linux/skbuff.h"
#include "linux/socket.h"
#include "linux/spinlock.h"
#include "linux/module.h"
#include "linux/init.h"
#include "linux/etherdevice.h"
#include "linux/list.h"
#include "linux/inetdevice.h"
#include "linux/ctype.h"
#include "linux/bootmem.h"
#include "linux/ethtool.h"
#include "linux/platform_device.h"
#include "asm/uaccess.h"
#include "user_util.h"
#include "kern_util.h"
#include "net_kern.h"
#include "net_user.h"
#include "mconsole_kern.h"
#include "init.h"
#include "irq_user.h"
#include "irq_kern.h"

static inline void set_ether_mac(struct net_device *dev, unsigned char *addr)
{
        memcpy(dev->dev_addr, addr, ETH_ALEN);
}

#define DRIVER_NAME "uml-netdev"

static DEFINE_SPINLOCK(opened_lock);
static LIST_HEAD(opened);

static int uml_net_rx(struct net_device *dev)
{
        struct uml_net_private *lp = dev->priv;
        int pkt_len;
        struct sk_buff *skb;

        /* If we can't allocate memory, try again next round. */
        skb = dev_alloc_skb(dev->mtu);
        if (skb == NULL) {
                lp->stats.rx_dropped++;
                return 0;
        }

        skb->dev = dev;
        skb_put(skb, dev->mtu);
        skb->mac.raw = skb->data;
        pkt_len = (*lp->read)(lp->fd, &skb, lp);

        if (pkt_len > 0) {
                skb_trim(skb, pkt_len);
                skb->protocol = (*lp->protocol)(skb);
                netif_rx(skb);

                lp->stats.rx_bytes += skb->len;
                lp->stats.rx_packets++;
                return pkt_len;
        }

        kfree_skb(skb);
        return pkt_len;
}

static void uml_dev_close(struct work_struct *work)
{
        struct uml_net_private *lp =
                container_of(work, struct uml_net_private, work);
        dev_close(lp->dev);
}

irqreturn_t uml_net_interrupt(int irq, void *dev_id)
{
        struct net_device *dev = dev_id;
        struct uml_net_private *lp = dev->priv;
        int err;

        if(!netif_running(dev))
                return(IRQ_NONE);

        spin_lock(&lp->lock);
        while((err = uml_net_rx(dev)) > 0) ;
        if(err < 0) {
                printk(KERN_ERR
                       "Device '%s' read returned %d, shutting it down\n",
                       dev->name, err);
                /* dev_close can't be called in interrupt context, and takes
                 * again lp->lock.
                 * And dev_close() can be safely called multiple times on the
                 * same device, since it tests for (dev->flags & IFF_UP). So
                 * there's no harm in delaying the device shutdown.
                 * Furthermore, the workqueue will not re-enqueue an already
                 * enqueued work item. */
                schedule_work(&lp->work);
                goto out;
        }
        reactivate_fd(lp->fd, UM_ETH_IRQ);

out:
        spin_unlock(&lp->lock);
        return(IRQ_HANDLED);
}

static int uml_net_open(struct net_device *dev)
{
        struct uml_net_private *lp = dev->priv;
        int err;

        if(lp->fd >= 0){
                err = -ENXIO;
                goto out;
        }

        lp->fd = (*lp->open)(&lp->user);
        if(lp->fd < 0){
                err = lp->fd;
                goto out;
        }

        err = um_request_irq(dev->irq, lp->fd, IRQ_READ, uml_net_interrupt,
                             IRQF_DISABLED | IRQF_SHARED, dev->name, dev);
        if(err != 0){
                printk(KERN_ERR "uml_net_open: failed to get irq(%d)\n", err);
                err = -ENETUNREACH;
                goto out_close;
        }

        lp->tl.data = (unsigned long) &lp->user;
        netif_start_queue(dev);

        /* clear buffer - it can happen that the host side of the interface
         * is full when we get here.  In this case, new data is never queued,
         * SIGIOs never arrive, and the net never works.
         */
        while((err = uml_net_rx(dev)) > 0) ;

        spin_lock(&opened_lock);
        list_add(&lp->list, &opened);
        spin_unlock(&opened_lock);

        return 0;
out_close:
        if(lp->close != NULL) (*lp->close)(lp->fd, &lp->user);
        lp->fd = -1;
out:
        return err;
}

static int uml_net_close(struct net_device *dev)
{
        struct uml_net_private *lp = dev->priv;

        netif_stop_queue(dev);

        free_irq(dev->irq, dev);
        if(lp->close != NULL)
                (*lp->close)(lp->fd, &lp->user);
        lp->fd = -1;

        spin_lock(&opened_lock);
        list_del(&lp->list);
        spin_unlock(&opened_lock);

        return 0;
}

static int uml_net_start_xmit(struct sk_buff *skb, struct net_device *dev)
{
        struct uml_net_private *lp = dev->priv;
        unsigned long flags;
        int len;

        netif_stop_queue(dev);

        spin_lock_irqsave(&lp->lock, flags);

        len = (*lp->write)(lp->fd, &skb, lp);

        if(len == skb->len) {
                lp->stats.tx_packets++;
                lp->stats.tx_bytes += skb->len;
                dev->trans_start = jiffies;
                netif_start_queue(dev);

                /* this is normally done in the interrupt when tx finishes */
                netif_wake_queue(dev);
        }
        else if(len == 0){
                netif_start_queue(dev);
                lp->stats.tx_dropped++;
        }
        else {
                netif_start_queue(dev);
                printk(KERN_ERR "uml_net_start_xmit: failed(%d)\n", len);
        }

        spin_unlock_irqrestore(&lp->lock, flags);

        dev_kfree_skb(skb);

        return 0;
}

static struct net_device_stats *uml_net_get_stats(struct net_device *dev)
{
        struct uml_net_private *lp = dev->priv;
        return &lp->stats;
}

static void uml_net_set_multicast_list(struct net_device *dev)
{
        if (dev->flags & IFF_PROMISC) return;
        else if (dev->mc_count) dev->flags |= IFF_ALLMULTI;
        else dev->flags &= ~IFF_ALLMULTI;
}

static void uml_net_tx_timeout(struct net_device *dev)
{
        dev->trans_start = jiffies;
        netif_wake_queue(dev);
}

static int uml_net_set_mac(struct net_device *dev, void *addr)
{
        struct uml_net_private *lp = dev->priv;
        struct sockaddr *hwaddr = addr;

        spin_lock_irq(&lp->lock);
        set_ether_mac(dev, hwaddr->sa_data);
        spin_unlock_irq(&lp->lock);

        return(0);
}

static int uml_net_change_mtu(struct net_device *dev, int new_mtu)
{
        struct uml_net_private *lp = dev->priv;
        int err = 0;

        spin_lock_irq(&lp->lock);

        new_mtu = (*lp->set_mtu)(new_mtu, &lp->user);
        if(new_mtu < 0){
                err = new_mtu;
                goto out;
        }

        dev->mtu = new_mtu;

 out:
        spin_unlock_irq(&lp->lock);
        return err;
}

static void uml_net_get_drvinfo(struct net_device *dev,
                                struct ethtool_drvinfo *info)
{
        strcpy(info->driver, DRIVER_NAME);
        strcpy(info->version, "42");
}

static struct ethtool_ops uml_net_ethtool_ops = {
        .get_drvinfo    = uml_net_get_drvinfo,
        .get_link       = ethtool_op_get_link,
};

void uml_net_user_timer_expire(unsigned long _conn)
{
#ifdef undef
        struct connection *conn = (struct connection *)_conn;

        dprintk(KERN_INFO "uml_net_user_timer_expire [%p]\n", conn);
        do_connect(conn);
#endif
}

static void setup_etheraddr(char *str, unsigned char *addr)
{
        char *end;
        int i;

        if(str == NULL)
                goto random;

        for(i=0;i<6;i++){
                addr[i] = simple_strtoul(str, &end, 16);
                if((end == str) ||
                   ((*end != ':') && (*end != ',') && (*end != '\0'))){
                        printk(KERN_ERR
                               "setup_etheraddr: failed to parse '%s' "
                               "as an ethernet address\n", str);
                        goto random;
                }
                str = end + 1;
        }
        if(addr[0] & 1){
                printk(KERN_ERR
                       "Attempt to assign a broadcast ethernet address to a "
                       "device disallowed\n");
                goto random;
        }
        return;

random:
        random_ether_addr(addr);
}

static DEFINE_SPINLOCK(devices_lock);
static LIST_HEAD(devices);

static struct platform_driver uml_net_driver = {
        .driver = {
                .name  = DRIVER_NAME,
        },
};
static int driver_registered;

static int eth_configure(int n, void *init, char *mac,
                         struct transport *transport)
{
        struct uml_net *device;
        struct net_device *dev;
        struct uml_net_private *lp;
        int save, err, size;

        size = transport->private_size + sizeof(struct uml_net_private) +
                sizeof(((struct uml_net_private *) 0)->user);

        device = kzalloc(sizeof(*device), GFP_KERNEL);
        if (device == NULL) {
                printk(KERN_ERR "eth_configure failed to allocate uml_net\n");
                return(1);
        }

        INIT_LIST_HEAD(&device->list);
        device->index = n;

        spin_lock(&devices_lock);
        list_add(&device->list, &devices);
        spin_unlock(&devices_lock);

        setup_etheraddr(mac, device->mac);

        printk(KERN_INFO "Netdevice %d ", n);
        printk("(%02x:%02x:%02x:%02x:%02x:%02x) ",
               device->mac[0], device->mac[1],
               device->mac[2], device->mac[3],
               device->mac[4], device->mac[5]);
        printk(": ");
        dev = alloc_etherdev(size);
        if (dev == NULL) {
                printk(KERN_ERR "eth_configure: failed to allocate device\n");
                return 1;
        }

        lp = dev->priv;
        /* This points to the transport private data. It's still clear, but we
         * must memset it to 0 *now*. Let's help the drivers. */
        memset(lp, 0, size);
        INIT_WORK(&lp->work, uml_dev_close);

        /* sysfs register */
        if (!driver_registered) {
                platform_driver_register(&uml_net_driver);
                driver_registered = 1;
        }
        device->pdev.id = n;
        device->pdev.name = DRIVER_NAME;
        platform_device_register(&device->pdev);
        SET_NETDEV_DEV(dev,&device->pdev.dev);

        /* If this name ends up conflicting with an existing registered
         * netdevice, that is OK, register_netdev{,ice}() will notice this
         * and fail.
         */
        snprintf(dev->name, sizeof(dev->name), "eth%d", n);
        device->dev = dev;

        (*transport->kern->init)(dev, init);

        dev->mtu = transport->user->max_packet;
        dev->open = uml_net_open;
        dev->hard_start_xmit = uml_net_start_xmit;
        dev->stop = uml_net_close;
        dev->get_stats = uml_net_get_stats;
        dev->set_multicast_list = uml_net_set_multicast_list;
        dev->tx_timeout = uml_net_tx_timeout;
        dev->set_mac_address = uml_net_set_mac;
        dev->change_mtu = uml_net_change_mtu;
        dev->ethtool_ops = &uml_net_ethtool_ops;
        dev->watchdog_timeo = (HZ >> 1);
        dev->irq = UM_ETH_IRQ;

        rtnl_lock();
        err = register_netdevice(dev);
        rtnl_unlock();
        if (err) {
                device->dev = NULL;
                /* XXX: should we call ->remove() here? */
                free_netdev(dev);
                return 1;
        }

        /* lp.user is the first four bytes of the transport data, which
         * has already been initialized.  This structure assignment will
         * overwrite that, so we make sure that .user gets overwritten with
         * what it already has.
         */
        save = lp->user[0];
        *lp = ((struct uml_net_private)
                { .list                 = LIST_HEAD_INIT(lp->list),
                  .dev                  = dev,
                  .fd                   = -1,
                  .mac                  = { 0xfe, 0xfd, 0x0, 0x0, 0x0, 0x0},
                  .protocol             = transport->kern->protocol,
                  .open                 = transport->user->open,
                  .close                = transport->user->close,
                  .remove               = transport->user->remove,
                  .read                 = transport->kern->read,
                  .write                = transport->kern->write,
                  .add_address          = transport->user->add_address,
                  .delete_address       = transport->user->delete_address,
                  .set_mtu              = transport->user->set_mtu,
                  .user                 = { save } });

        init_timer(&lp->tl);
        spin_lock_init(&lp->lock);
        lp->tl.function = uml_net_user_timer_expire;
        memcpy(lp->mac, device->mac, sizeof(lp->mac));

        if (transport->user->init)
                (*transport->user->init)(&lp->user, dev);

        set_ether_mac(dev, device->mac);

        return 0;
}

static struct uml_net *find_device(int n)
{
        struct uml_net *device;
        struct list_head *ele;

        spin_lock(&devices_lock);
        list_for_each(ele, &devices){
                device = list_entry(ele, struct uml_net, list);
                if(device->index == n)
                        goto out;
        }
        device = NULL;
 out:
        spin_unlock(&devices_lock);
        return(device);
}

static int eth_parse(char *str, int *index_out, char **str_out,
                     char **error_out)
{
        char *end;
        int n, err = -EINVAL;;

        n = simple_strtoul(str, &end, 0);
        if(end == str){
                *error_out = "Bad device number";
                return err;
        }

        str = end;
        if(*str != '='){
                *error_out = "Expected '=' after device number";
                return err;
        }

        str++;
        if(find_device(n)){
                *error_out = "Device already configured";
                return err;
        }

        *index_out = n;
        *str_out = str;
        return 0;
}

struct eth_init {
        struct list_head list;
        char *init;
        int index;
};

static DEFINE_SPINLOCK(transports_lock);
static LIST_HEAD(transports);

/* Filled in during early boot */
struct list_head eth_cmd_line = LIST_HEAD_INIT(eth_cmd_line);

static int check_transport(struct transport *transport, char *eth, int n,
                           void **init_out, char **mac_out)
{
        int len;

        len = strlen(transport->name);
        if(strncmp(eth, transport->name, len))
                return(0);

        eth += len;
        if(*eth == ',')
                eth++;
        else if(*eth != '\0')
                return(0);

        *init_out = kmalloc(transport->setup_size, GFP_KERNEL);
        if(*init_out == NULL)
                return(1);

        if(!transport->setup(eth, mac_out, *init_out)){
                kfree(*init_out);
                *init_out = NULL;
        }
        return(1);
}

void register_transport(struct transport *new)
{
        struct list_head *ele, *next;
        struct eth_init *eth;
        void *init;
        char *mac = NULL;
        int match;

        spin_lock(&transports_lock);
        BUG_ON(!list_empty(&new->list));
        list_add(&new->list, &transports);
        spin_unlock(&transports_lock);

        list_for_each_safe(ele, next, &eth_cmd_line){
                eth = list_entry(ele, struct eth_init, list);
                match = check_transport(new, eth->init, eth->index, &init,
                                        &mac);
                if(!match)
                        continue;
                else if(init != NULL){
                        eth_configure(eth->index, init, mac, new);
                        kfree(init);
                }
                list_del(&eth->list);
        }
}

static int eth_setup_common(char *str, int index)
{
        struct list_head *ele;
        struct transport *transport;
        void *init;
        char *mac = NULL;

        list_for_each(ele, &transports){
                transport = list_entry(ele, struct transport, list);
                if(!check_transport(transport, str, index, &init, &mac))
                        continue;
                if(init != NULL){
                        eth_configure(index, init, mac, transport);
                        kfree(init);
                }
                return(1);
        }
        return(0);
}

static int eth_setup(char *str)
{
        struct eth_init *new;
        char *error;
        int n, err;

        err = eth_parse(str, &n, &str, &error);
        if(err){
                printk(KERN_ERR "eth_setup - Couldn't parse '%s' : %s\n",
                       str, error);
                return 1;
        }

        new = alloc_bootmem(sizeof(*new));
        if (new == NULL){
                printk("eth_init : alloc_bootmem failed\n");
                return 1;
        }

        INIT_LIST_HEAD(&new->list);
        new->index = n;
        new->init = str;

        list_add_tail(&new->list, &eth_cmd_line);
        return 1;
}

__setup("eth", eth_setup);
__uml_help(eth_setup,
"eth[0-9]+=<transport>,<options>\n"
"    Configure a network device.\n\n"
);

#if 0
static int eth_init(void)
{
        struct list_head *ele, *next;
        struct eth_init *eth;

        list_for_each_safe(ele, next, &eth_cmd_line){
                eth = list_entry(ele, struct eth_init, list);

                if(eth_setup_common(eth->init, eth->index))
                        list_del(&eth->list);
        }

        return(1);
}
__initcall(eth_init);
#endif

static int net_config(char *str, char **error_out)
{
        int n, err;

        err = eth_parse(str, &n, &str, error_out);
        if(err)
                return err;

        /* This string is broken up and the pieces used by the underlying
         * driver.  So, it is freed only if eth_setup_common fails.
         */
        str = kstrdup(str, GFP_KERNEL);
        if(str == NULL){
                *error_out = "net_config failed to strdup string";
                return -ENOMEM;
        }
        err = !eth_setup_common(str, n);
        if(err)
                kfree(str);
        return(err);
}

static int net_id(char **str, int *start_out, int *end_out)
{
        char *end;
        int n;

        n = simple_strtoul(*str, &end, 0);
        if((*end != '\0') || (end == *str))
                return -1;

        *start_out = n;
        *end_out = n;
        *str = end;
        return n;
}

static int net_remove(int n, char **error_out)
{
        struct uml_net *device;
        struct net_device *dev;
        struct uml_net_private *lp;

        device = find_device(n);
        if(device == NULL)
                return -ENODEV;

        dev = device->dev;
        lp = dev->priv;
        if(lp->fd > 0)
                return -EBUSY;
        if(lp->remove != NULL) (*lp->remove)(&lp->user);
        unregister_netdev(dev);
        platform_device_unregister(&device->pdev);

        list_del(&device->list);
        kfree(device);
        free_netdev(dev);
        return 0;
}

static struct mc_device net_mc = {
        .name           = "eth",
        .config         = net_config,
        .get_config     = NULL,
        .id             = net_id,
        .remove         = net_remove,
};

static int uml_inetaddr_event(struct notifier_block *this, unsigned long event,
                              void *ptr)
{
        struct in_ifaddr *ifa = ptr;
        struct net_device *dev = ifa->ifa_dev->dev;
        struct uml_net_private *lp;
        void (*proc)(unsigned char *, unsigned char *, void *);
        unsigned char addr_buf[4], netmask_buf[4];

        if(dev->open != uml_net_open) return(NOTIFY_DONE);

        lp = dev->priv;

        proc = NULL;
        switch (event){
        case NETDEV_UP:
                proc = lp->add_address;
                break;
        case NETDEV_DOWN:
                proc = lp->delete_address;
                break;
        }
        if(proc != NULL){
                memcpy(addr_buf, &ifa->ifa_address, sizeof(addr_buf));
                memcpy(netmask_buf, &ifa->ifa_mask, sizeof(netmask_buf));
                (*proc)(addr_buf, netmask_buf, &lp->user);
        }
        return(NOTIFY_DONE);
}

struct notifier_block uml_inetaddr_notifier = {
        .notifier_call          = uml_inetaddr_event,
};

static int uml_net_init(void)
{
        struct list_head *ele;
        struct uml_net_private *lp;
        struct in_device *ip;
        struct in_ifaddr *in;

        mconsole_register_dev(&net_mc);
        register_inetaddr_notifier(&uml_inetaddr_notifier);

        /* Devices may have been opened already, so the uml_inetaddr_notifier
         * didn't get a chance to run for them.  This fakes it so that
         * addresses which have already been set up get handled properly.
         */
        list_for_each(ele, &opened){
                lp = list_entry(ele, struct uml_net_private, list);
                ip = lp->dev->ip_ptr;
                if(ip == NULL) continue;
                in = ip->ifa_list;
                while(in != NULL){
                        uml_inetaddr_event(NULL, NETDEV_UP, in);
                        in = in->ifa_next;
                }
        }

        return(0);
}

__initcall(uml_net_init);

static void close_devices(void)
{
        struct list_head *ele;
        struct uml_net_private *lp;

        list_for_each(ele, &opened){
                lp = list_entry(ele, struct uml_net_private, list);
                free_irq(lp->dev->irq, lp->dev);
                if((lp->close != NULL) && (lp->fd >= 0))
                        (*lp->close)(lp->fd, &lp->user);
                if(lp->remove != NULL) (*lp->remove)(&lp->user);
        }
}

__uml_exitcall(close_devices);

struct sk_buff *ether_adjust_skb(struct sk_buff *skb, int extra)
{
        if((skb != NULL) && (skb_tailroom(skb) < extra)){
                struct sk_buff *skb2;

                skb2 = skb_copy_expand(skb, 0, extra, GFP_ATOMIC);
                dev_kfree_skb(skb);
                skb = skb2;
        }
        if(skb != NULL) skb_put(skb, extra);
        return(skb);
}

void iter_addresses(void *d, void (*cb)(unsigned char *, unsigned char *,
                                        void *),
                    void *arg)
{
        struct net_device *dev = d;
        struct in_device *ip = dev->ip_ptr;
        struct in_ifaddr *in;
        unsigned char address[4], netmask[4];

        if(ip == NULL) return;
        in = ip->ifa_list;
        while(in != NULL){
                memcpy(address, &in->ifa_address, sizeof(address));
                memcpy(netmask, &in->ifa_mask, sizeof(netmask));
                (*cb)(address, netmask, arg);
                in = in->ifa_next;
        }
}

int dev_netmask(void *d, void *m)
{
        struct net_device *dev = d;
        struct in_device *ip = dev->ip_ptr;
        struct in_ifaddr *in;
        __be32 *mask_out = m;

        if(ip == NULL)
                return(1);

        in = ip->ifa_list;
        if(in == NULL)
                return(1);

        *mask_out = in->ifa_mask;
        return(0);
}

void *get_output_buffer(int *len_out)
{
        void *ret;

        ret = (void *) __get_free_pages(GFP_KERNEL, 0);
        if(ret) *len_out = PAGE_SIZE;
        else *len_out = 0;
        return(ret);
}

void free_output_buffer(void *buffer)
{
        free_pages((unsigned long) buffer, 0);
}

int tap_setup_common(char *str, char *type, char **dev_name, char **mac_out,
                     char **gate_addr)
{
        char *remain;

        remain = split_if_spec(str, dev_name, mac_out, gate_addr, NULL);
        if(remain != NULL){
                printk("tap_setup_common - Extra garbage on specification : "
                       "'%s'\n", remain);
                return(1);
        }

        return(0);
}

unsigned short eth_protocol(struct sk_buff *skb)
{
        return(eth_type_trans(skb, skb->dev));
}