ccid.c

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/*
 *  net/dccp/ccid.c
 *
 *  An implementation of the DCCP protocol
 *  Arnaldo Carvalho de Melo <[email protected]>
 *
 *  CCID infrastructure
 *
 *  This program is free software; you can redistribute it and/or modify it
 *  under the terms of the GNU General Public License version 2 as
 *  published by the Free Software Foundation.
 */

#include <linux/slab.h>

#include "ccid.h"
#include "ccids/lib/tfrc.h"

static struct ccid_operations *ccids[] = {
    &ccid2_ops,
#ifdef CONFIG_IP_DCCP_CCID3
    &ccid3_ops,
#endif
};

static struct ccid_operations *ccid_by_number(const u8 id)
{
    int i;

    for (i = 0; i < ARRAY_SIZE(ccids); i++)
        if (ccids[i]->ccid_id == id)
            return ccids[i];
    return NULL;
}

/* check that up to @array_len members in @ccid_array are supported */
bool ccid_support_check(u8 const *ccid_array, u8 array_len)
{
    while (array_len > 0)
        if (ccid_by_number(ccid_array[--array_len]) == NULL)
            return false;
    return true;
}

int ccid_get_builtin_ccids(u8 **ccid_array, u8 *array_len)
{
    *ccid_array = kmalloc(ARRAY_SIZE(ccids), gfp_any());
    if (*ccid_array == NULL)
        return -ENOBUFS;

    for (*array_len = 0; *array_len < ARRAY_SIZE(ccids); *array_len += 1)
        (*ccid_array)[*array_len] = ccids[*array_len]->ccid_id;
    return 0;
}

int ccid_getsockopt_builtin_ccids(struct sock *sk, int len,
                  char __user *optval, int __user *optlen)
{
    u8 *ccid_array, array_len;
    int err = 0;

    if (ccid_get_builtin_ccids(&ccid_array, &array_len))
        return -ENOBUFS;

    if (put_user(array_len, optlen))
        err = -EFAULT;
    else if (len > 0 && copy_to_user(optval, ccid_array,
                     len > array_len ? array_len : len))
        err = -EFAULT;

    kfree(ccid_array);
    return err;
}

static struct kmem_cache *ccid_kmem_cache_create(int obj_size, char *slab_name_fmt, const char *fmt,...)
{
    struct kmem_cache *slab;
    va_list args;

    va_start(args, fmt);
    vsnprintf(slab_name_fmt, CCID_SLAB_NAME_LENGTH, fmt, args);
    va_end(args);

    slab = kmem_cache_create(slab_name_fmt, sizeof(struct ccid) + obj_size, 0,
                 SLAB_HWCACHE_ALIGN, NULL);
    return slab;
}

static void ccid_kmem_cache_destroy(struct kmem_cache *slab)
{
    if (slab != NULL)
        kmem_cache_destroy(slab);
}

static int ccid_activate(struct ccid_operations *ccid_ops)
{
    int err = -ENOBUFS;

    ccid_ops->ccid_hc_rx_slab =
            ccid_kmem_cache_create(ccid_ops->ccid_hc_rx_obj_size,
                           ccid_ops->ccid_hc_rx_slab_name,
                           "ccid%u_hc_rx_sock",
                           ccid_ops->ccid_id);
    if (ccid_ops->ccid_hc_rx_slab == NULL)
        goto out;

    ccid_ops->ccid_hc_tx_slab =
            ccid_kmem_cache_create(ccid_ops->ccid_hc_tx_obj_size,
                           ccid_ops->ccid_hc_tx_slab_name,
                           "ccid%u_hc_tx_sock",
                           ccid_ops->ccid_id);
    if (ccid_ops->ccid_hc_tx_slab == NULL)
        goto out_free_rx_slab;

    pr_info("DCCP: Activated CCID %d (%s)\n",
        ccid_ops->ccid_id, ccid_ops->ccid_name);
    err = 0;
out:
    return err;
out_free_rx_slab:
    ccid_kmem_cache_destroy(ccid_ops->ccid_hc_rx_slab);
    ccid_ops->ccid_hc_rx_slab = NULL;
    goto out;
}

static void ccid_deactivate(struct ccid_operations *ccid_ops)
{
    ccid_kmem_cache_destroy(ccid_ops->ccid_hc_tx_slab);
    ccid_ops->ccid_hc_tx_slab = NULL;
    ccid_kmem_cache_destroy(ccid_ops->ccid_hc_rx_slab);
    ccid_ops->ccid_hc_rx_slab = NULL;

    pr_info("DCCP: Deactivated CCID %d (%s)\n",
        ccid_ops->ccid_id, ccid_ops->ccid_name);
}

struct ccid *ccid_new(const u8 id, struct sock *sk, bool rx)
{
    struct ccid_operations *ccid_ops = ccid_by_number(id);
    struct ccid *ccid = NULL;

    if (ccid_ops == NULL)
        goto out;

    ccid = kmem_cache_alloc(rx ? ccid_ops->ccid_hc_rx_slab :
                     ccid_ops->ccid_hc_tx_slab, gfp_any());
    if (ccid == NULL)
        goto out;
    ccid->ccid_ops = ccid_ops;
    if (rx) {
        memset(ccid + 1, 0, ccid_ops->ccid_hc_rx_obj_size);
        if (ccid->ccid_ops->ccid_hc_rx_init != NULL &&
            ccid->ccid_ops->ccid_hc_rx_init(ccid, sk) != 0)
            goto out_free_ccid;
    } else {
        memset(ccid + 1, 0, ccid_ops->ccid_hc_tx_obj_size);
        if (ccid->ccid_ops->ccid_hc_tx_init != NULL &&
            ccid->ccid_ops->ccid_hc_tx_init(ccid, sk) != 0)
            goto out_free_ccid;
    }
out:
    return ccid;
out_free_ccid:
    kmem_cache_free(rx ? ccid_ops->ccid_hc_rx_slab :
            ccid_ops->ccid_hc_tx_slab, ccid);
    ccid = NULL;
    goto out;
}

void ccid_hc_rx_delete(struct ccid *ccid, struct sock *sk)
{
    if (ccid != NULL) {
        if (ccid->ccid_ops->ccid_hc_rx_exit != NULL)
            ccid->ccid_ops->ccid_hc_rx_exit(sk);
        kmem_cache_free(ccid->ccid_ops->ccid_hc_rx_slab, ccid);
    }
}

void ccid_hc_tx_delete(struct ccid *ccid, struct sock *sk)
{
    if (ccid != NULL) {
        if (ccid->ccid_ops->ccid_hc_tx_exit != NULL)
            ccid->ccid_ops->ccid_hc_tx_exit(sk);
        kmem_cache_free(ccid->ccid_ops->ccid_hc_tx_slab, ccid);
    }
}

int __init ccid_initialize_builtins(void)
{
    int i, err = tfrc_lib_init();

    if (err)
        return err;

    for (i = 0; i < ARRAY_SIZE(ccids); i++) {
        err = ccid_activate(ccids[i]);
        if (err)
            goto unwind_registrations;
    }
    return 0;

unwind_registrations:
    while(--i >= 0)
        ccid_deactivate(ccids[i]);
    tfrc_lib_exit();
    return err;
}

void ccid_cleanup_builtins(void)
{
    int i;

    for (i = 0; i < ARRAY_SIZE(ccids); i++)
        ccid_deactivate(ccids[i]);
    tfrc_lib_exit();
}