cregit-Linux how code gets into the kernel

Release 4.11 net/netfilter/nft_set_bitmap.c

Directory: net/netfilter
/*
 * Copyright (c) 2017 Pablo Neira Ayuso <pablo@netfilter.org>
 *
 * 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/kernel.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/list.h>
#include <linux/netlink.h>
#include <linux/netfilter.h>
#include <linux/netfilter/nf_tables.h>
#include <net/netfilter/nf_tables.h>


struct nft_bitmap_elem {
	
struct list_head	head;
	
struct nft_set_ext	ext;
};

/* This bitmap uses two bits to represent one element. These two bits determine
 * the element state in the current and the future generation.
 *
 * An element can be in three states. The generation cursor is represented using
 * the ^ character, note that this cursor shifts on every succesful transaction.
 * If no transaction is going on, we observe all elements are in the following
 * state:
 *
 * 11 = this element is active in the current generation. In case of no updates,
 * ^    it stays active in the next generation.
 * 00 = this element is inactive in the current generation. In case of no
 * ^    updates, it stays inactive in the next generation.
 *
 * On transaction handling, we observe these two temporary states:
 *
 * 01 = this element is inactive in the current generation and it becomes active
 * ^    in the next one. This happens when the element is inserted but commit
 *      path has not yet been executed yet, so activation is still pending. On
 *      transaction abortion, the element is removed.
 * 10 = this element is active in the current generation and it becomes inactive
 * ^    in the next one. This happens when the element is deactivated but commit
 *      path has not yet been executed yet, so removal is still pending. On
 *      transation abortion, the next generation bit is reset to go back to
 *      restore its previous state.
 */

struct nft_bitmap {
	
struct	list_head	list;
	
u16			bitmap_size;
	
u8			bitmap[];
};


static inline void nft_bitmap_location(const struct nft_set *set, const void *key, u32 *idx, u32 *off) { u32 k; if (set->klen == 2) k = *(u16 *)key; else k = *(u8 *)key; k <<= 1; *idx = k / BITS_PER_BYTE; *off = k % BITS_PER_BYTE; }

Contributors

PersonTokensPropCommitsCommitProp
Liping Zhang3851.35%150.00%
Pablo Neira Ayuso3648.65%150.00%
Total74100.00%2100.00%

/* Fetch the two bits that represent the element and check if it is active based * on the generation mask. */
static inline bool nft_bitmap_active(const u8 *bitmap, u32 idx, u32 off, u8 genmask) { return (bitmap[idx] & (0x3 << off)) & (genmask << off); }

Contributors

PersonTokensPropCommitsCommitProp
Pablo Neira Ayuso41100.00%1100.00%
Total41100.00%1100.00%


static bool nft_bitmap_lookup(const struct net *net, const struct nft_set *set, const u32 *key, const struct nft_set_ext **ext) { const struct nft_bitmap *priv = nft_set_priv(set); u8 genmask = nft_genmask_cur(net); u32 idx, off; nft_bitmap_location(set, key, &idx, &off); return nft_bitmap_active(priv->bitmap, idx, off, genmask); }

Contributors

PersonTokensPropCommitsCommitProp
Pablo Neira Ayuso7997.53%150.00%
Liping Zhang22.47%150.00%
Total81100.00%2100.00%


static struct nft_bitmap_elem * nft_bitmap_elem_find(const struct nft_set *set, struct nft_bitmap_elem *this, u8 genmask) { const struct nft_bitmap *priv = nft_set_priv(set); struct nft_bitmap_elem *be; list_for_each_entry_rcu(be, &priv->list, head) { if (memcmp(nft_set_ext_key(&be->ext), nft_set_ext_key(&this->ext), set->klen) || !nft_set_elem_active(&be->ext, genmask)) continue; return be; } return NULL; }

Contributors

PersonTokensPropCommitsCommitProp
Pablo Neira Ayuso91100.00%1100.00%
Total91100.00%1100.00%


static int nft_bitmap_insert(const struct net *net, const struct nft_set *set, const struct nft_set_elem *elem, struct nft_set_ext **ext) { struct nft_bitmap *priv = nft_set_priv(set); struct nft_bitmap_elem *new = elem->priv, *be; u8 genmask = nft_genmask_next(net); u32 idx, off; be = nft_bitmap_elem_find(set, new, genmask); if (be) { *ext = &be->ext; return -EEXIST; } nft_bitmap_location(set, nft_set_ext_key(&new->ext), &idx, &off); /* Enter 01 state. */ priv->bitmap[idx] |= (genmask << off); list_add_tail_rcu(&new->head, &priv->list); return 0; }

Contributors

PersonTokensPropCommitsCommitProp
Pablo Neira Ayuso14198.60%266.67%
Liping Zhang21.40%133.33%
Total143100.00%3100.00%


static void nft_bitmap_remove(const struct net *net, const struct nft_set *set, const struct nft_set_elem *elem) { struct nft_bitmap *priv = nft_set_priv(set); struct nft_bitmap_elem *be = elem->priv; u8 genmask = nft_genmask_next(net); u32 idx, off; nft_bitmap_location(set, nft_set_ext_key(&be->ext), &idx, &off); /* Enter 00 state. */ priv->bitmap[idx] &= ~(genmask << off); list_del_rcu(&be->head); }

Contributors

PersonTokensPropCommitsCommitProp
Pablo Neira Ayuso9697.96%266.67%
Liping Zhang22.04%133.33%
Total98100.00%3100.00%


static void nft_bitmap_activate(const struct net *net, const struct nft_set *set, const struct nft_set_elem *elem) { struct nft_bitmap *priv = nft_set_priv(set); struct nft_bitmap_elem *be = elem->priv; u8 genmask = nft_genmask_next(net); u32 idx, off; nft_bitmap_location(set, nft_set_ext_key(&be->ext), &idx, &off); /* Enter 11 state. */ priv->bitmap[idx] |= (genmask << off); nft_set_elem_change_active(net, set, &be->ext); }

Contributors

PersonTokensPropCommitsCommitProp
Pablo Neira Ayuso9998.02%266.67%
Liping Zhang21.98%133.33%
Total101100.00%3100.00%


static bool nft_bitmap_flush(const struct net *net, const struct nft_set *set, void *_be) { struct nft_bitmap *priv = nft_set_priv(set); u8 genmask = nft_genmask_next(net); struct nft_bitmap_elem *be = _be; u32 idx, off; nft_bitmap_location(set, nft_set_ext_key(&be->ext), &idx, &off); /* Enter 10 state, similar to deactivation. */ priv->bitmap[idx] &= ~(genmask << off); nft_set_elem_change_active(net, set, &be->ext); return true; }

Contributors

PersonTokensPropCommitsCommitProp
Pablo Neira Ayuso9998.02%266.67%
Liping Zhang21.98%133.33%
Total101100.00%3100.00%


static void *nft_bitmap_deactivate(const struct net *net, const struct nft_set *set, const struct nft_set_elem *elem) { struct nft_bitmap *priv = nft_set_priv(set); struct nft_bitmap_elem *this = elem->priv, *be; u8 genmask = nft_genmask_next(net); u32 idx, off; nft_bitmap_location(set, elem->key.val.data, &idx, &off); be = nft_bitmap_elem_find(set, this, genmask); if (!be) return NULL; /* Enter 10 state. */ priv->bitmap[idx] &= ~(genmask << off); nft_set_elem_change_active(net, set, &be->ext); return be; }

Contributors

PersonTokensPropCommitsCommitProp
Pablo Neira Ayuso12698.44%266.67%
Liping Zhang21.56%133.33%
Total128100.00%3100.00%


static void nft_bitmap_walk(const struct nft_ctx *ctx, struct nft_set *set, struct nft_set_iter *iter) { const struct nft_bitmap *priv = nft_set_priv(set); struct nft_bitmap_elem *be; struct nft_set_elem elem; list_for_each_entry_rcu(be, &priv->list, head) { if (iter->count < iter->skip) goto cont; if (!nft_set_elem_active(&be->ext, iter->genmask)) goto cont; elem.priv = be; iter->err = iter->fn(ctx, set, iter, &elem); if (iter->err < 0) return; cont: iter->count++; } }

Contributors

PersonTokensPropCommitsCommitProp
Pablo Neira Ayuso123100.00%2100.00%
Total123100.00%2100.00%

/* The bitmap size is pow(2, key length in bits) / bits per byte. This is * multiplied by two since each element takes two bits. For 8 bit keys, the * bitmap consumes 66 bytes. For 16 bit keys, 16388 bytes. */
static inline u32 nft_bitmap_size(u32 klen) { return ((2 << ((klen * BITS_PER_BYTE) - 1)) / BITS_PER_BYTE) << 1; }

Contributors

PersonTokensPropCommitsCommitProp
Pablo Neira Ayuso31100.00%1100.00%
Total31100.00%1100.00%


static inline u32 nft_bitmap_total_size(u32 klen) { return sizeof(struct nft_bitmap) + nft_bitmap_size(klen); }

Contributors

PersonTokensPropCommitsCommitProp
Pablo Neira Ayuso22100.00%1100.00%
Total22100.00%1100.00%


static unsigned int nft_bitmap_privsize(const struct nlattr * const nla[]) { u32 klen = ntohl(nla_get_be32(nla[NFTA_SET_KEY_LEN])); return nft_bitmap_total_size(klen); }

Contributors

PersonTokensPropCommitsCommitProp
Pablo Neira Ayuso35100.00%1100.00%
Total35100.00%1100.00%


static int nft_bitmap_init(const struct nft_set *set, const struct nft_set_desc *desc, const struct nlattr * const nla[]) { struct nft_bitmap *priv = nft_set_priv(set); INIT_LIST_HEAD(&priv->list); priv->bitmap_size = nft_bitmap_size(set->klen); return 0; }

Contributors

PersonTokensPropCommitsCommitProp
Pablo Neira Ayuso58100.00%3100.00%
Total58100.00%3100.00%


static void nft_bitmap_destroy(const struct nft_set *set) { }

Contributors

PersonTokensPropCommitsCommitProp
Pablo Neira Ayuso11100.00%1100.00%
Total11100.00%1100.00%


static bool nft_bitmap_estimate(const struct nft_set_desc *desc, u32 features, struct nft_set_estimate *est) { /* Make sure bitmaps we don't get bitmaps larger than 16 Kbytes. */ if (desc->klen > 2) return false; est->size = nft_bitmap_total_size(desc->klen); est->lookup = NFT_SET_CLASS_O_1; est->space = NFT_SET_CLASS_O_1; return true; }

Contributors

PersonTokensPropCommitsCommitProp
Pablo Neira Ayuso58100.00%1100.00%
Total58100.00%1100.00%

static struct nft_set_ops nft_bitmap_ops __read_mostly = { .privsize = nft_bitmap_privsize, .elemsize = offsetof(struct nft_bitmap_elem, ext), .estimate = nft_bitmap_estimate, .init = nft_bitmap_init, .destroy = nft_bitmap_destroy, .insert = nft_bitmap_insert, .remove = nft_bitmap_remove, .deactivate = nft_bitmap_deactivate, .flush = nft_bitmap_flush, .activate = nft_bitmap_activate, .lookup = nft_bitmap_lookup, .walk = nft_bitmap_walk, .owner = THIS_MODULE, };
static int __init nft_bitmap_module_init(void) { return nft_register_set(&nft_bitmap_ops); }

Contributors

PersonTokensPropCommitsCommitProp
Pablo Neira Ayuso16100.00%1100.00%
Total16100.00%1100.00%


static void __exit nft_bitmap_module_exit(void) { nft_unregister_set(&nft_bitmap_ops); }

Contributors

PersonTokensPropCommitsCommitProp
Pablo Neira Ayuso15100.00%1100.00%
Total15100.00%1100.00%

module_init(nft_bitmap_module_init); module_exit(nft_bitmap_module_exit); MODULE_LICENSE("GPL"); MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>"); MODULE_ALIAS_NFT_SET();

Overall Contributors

PersonTokensPropCommitsCommitProp
Pablo Neira Ayuso133696.39%375.00%
Liping Zhang503.61%125.00%
Total1386100.00%4100.00%
Directory: net/netfilter
Information contained on this website is for historical information purposes only and does not indicate or represent copyright ownership.
Created with cregit.