hash.c
/*
* (C) 2016 by Laura Garcia <nevola@gmail.com>
*
* 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.
*
*/
#include <stdio.h>
#include <stdint.h>
#include <string.h>
#include <arpa/inet.h>
#include <errno.h>
#include <linux/netfilter/nf_tables.h>
#include "internal.h"
#include <libmnl/libmnl.h>
#include <libnftnl/expr.h>
#include <libnftnl/rule.h>
struct nftnl_expr_hash {
enum nft_hash_types type;
enum nft_registers sreg;
enum nft_registers dreg;
unsigned int len;
unsigned int modulus;
unsigned int seed;
unsigned int offset;
};
static int
nftnl_expr_hash_set(struct nftnl_expr *e, uint16_t type,
const void *data, uint32_t data_len)
{
struct nftnl_expr_hash *hash = nftnl_expr_data(e);
switch (type) {
case NFTNL_EXPR_HASH_SREG:
memcpy(&hash->sreg, data, sizeof(hash->sreg));
break;
case NFTNL_EXPR_HASH_DREG:
memcpy(&hash->dreg, data, sizeof(hash->dreg));
break;
case NFTNL_EXPR_HASH_LEN:
memcpy(&hash->len, data, sizeof(hash->len));
break;
case NFTNL_EXPR_HASH_MODULUS:
memcpy(&hash->modulus, data, sizeof(hash->modulus));
break;
case NFTNL_EXPR_HASH_SEED:
memcpy(&hash->seed, data, sizeof(hash->seed));
break;
case NFTNL_EXPR_HASH_OFFSET:
memcpy(&hash->offset, data, sizeof(hash->offset));
break;
case NFTNL_EXPR_HASH_TYPE:
memcpy(&hash->type, data, sizeof(hash->type));
break;
default:
return -1;
}
return 0;
}
static const void *
nftnl_expr_hash_get(const struct nftnl_expr *e, uint16_t type,
uint32_t *data_len)
{
struct nftnl_expr_hash *hash = nftnl_expr_data(e);
switch (type) {
case NFTNL_EXPR_HASH_SREG:
*data_len = sizeof(hash->sreg);
return &hash->sreg;
case NFTNL_EXPR_HASH_DREG:
*data_len = sizeof(hash->dreg);
return &hash->dreg;
case NFTNL_EXPR_HASH_LEN:
*data_len = sizeof(hash->len);
return &hash->len;
case NFTNL_EXPR_HASH_MODULUS:
*data_len = sizeof(hash->modulus);
return &hash->modulus;
case NFTNL_EXPR_HASH_SEED:
*data_len = sizeof(hash->seed);
return &hash->seed;
case NFTNL_EXPR_HASH_OFFSET:
*data_len = sizeof(hash->offset);
return &hash->offset;
case NFTNL_EXPR_HASH_TYPE:
*data_len = sizeof(hash->type);
return &hash->type;
}
return NULL;
}
static int nftnl_expr_hash_cb(const struct nlattr *attr, void *data)
{
const struct nlattr **tb = data;
int type = mnl_attr_get_type(attr);
if (mnl_attr_type_valid(attr, NFTA_HASH_MAX) < 0)
return MNL_CB_OK;
switch (type) {
case NFTA_HASH_SREG:
case NFTA_HASH_DREG:
case NFTA_HASH_LEN:
case NFTA_HASH_MODULUS:
case NFTA_HASH_SEED:
case NFTA_HASH_OFFSET:
case NFTA_HASH_TYPE:
if (mnl_attr_validate(attr, MNL_TYPE_U32) < 0)
abi_breakage();
break;
}
tb[type] = attr;
return MNL_CB_OK;
}
static void
nftnl_expr_hash_build(struct nlmsghdr *nlh, const struct nftnl_expr *e)
{
struct nftnl_expr_hash *hash = nftnl_expr_data(e);
if (e->flags & (1 << NFTNL_EXPR_HASH_SREG))
mnl_attr_put_u32(nlh, NFTA_HASH_SREG, htonl(hash->sreg));
if (e->flags & (1 << NFTNL_EXPR_HASH_DREG))
mnl_attr_put_u32(nlh, NFTA_HASH_DREG, htonl(hash->dreg));
if (e->flags & (1 << NFTNL_EXPR_HASH_LEN))
mnl_attr_put_u32(nlh, NFTA_HASH_LEN, htonl(hash->len));
if (e->flags & (1 << NFTNL_EXPR_HASH_MODULUS))
mnl_attr_put_u32(nlh, NFTA_HASH_MODULUS, htonl(hash->modulus));
if (e->flags & (1 << NFTNL_EXPR_HASH_SEED))
mnl_attr_put_u32(nlh, NFTA_HASH_SEED, htonl(hash->seed));
if (e->flags & (1 << NFTNL_EXPR_HASH_OFFSET))
mnl_attr_put_u32(nlh, NFTA_HASH_OFFSET, htonl(hash->offset));
if (e->flags & (1 << NFTNL_EXPR_HASH_TYPE))
mnl_attr_put_u32(nlh, NFTA_HASH_TYPE, htonl(hash->type));
}
static int
nftnl_expr_hash_parse(struct nftnl_expr *e, struct nlattr *attr)
{
struct nftnl_expr_hash *hash = nftnl_expr_data(e);
struct nlattr *tb[NFTA_HASH_MAX+1] = {};
int ret = 0;
if (mnl_attr_parse_nested(attr, nftnl_expr_hash_cb, tb) < 0)
return -1;
if (tb[NFTA_HASH_SREG]) {
hash->sreg = ntohl(mnl_attr_get_u32(tb[NFTA_HASH_SREG]));
e->flags |= (1 << NFTNL_EXPR_HASH_SREG);
}
if (tb[NFTA_HASH_DREG]) {
hash->dreg = ntohl(mnl_attr_get_u32(tb[NFTA_HASH_DREG]));
e->flags |= (1 << NFTNL_EXPR_HASH_DREG);
}
if (tb[NFTA_HASH_LEN]) {
hash->len = ntohl(mnl_attr_get_u32(tb[NFTA_HASH_LEN]));
e->flags |= (1 << NFTNL_EXPR_HASH_LEN);
}
if (tb[NFTA_HASH_MODULUS]) {
hash->modulus = ntohl(mnl_attr_get_u32(tb[NFTA_HASH_MODULUS]));
e->flags |= (1 << NFTNL_EXPR_HASH_MODULUS);
}
if (tb[NFTA_HASH_SEED]) {
hash->seed = ntohl(mnl_attr_get_u32(tb[NFTA_HASH_SEED]));
e->flags |= (1 << NFTNL_EXPR_HASH_SEED);
}
if (tb[NFTA_HASH_OFFSET]) {
hash->offset = ntohl(mnl_attr_get_u32(tb[NFTA_HASH_OFFSET]));
e->flags |= (1 << NFTNL_EXPR_HASH_OFFSET);
}
if (tb[NFTA_HASH_TYPE]) {
hash->type = ntohl(mnl_attr_get_u32(tb[NFTA_HASH_TYPE]));
e->flags |= (1 << NFTNL_EXPR_HASH_TYPE);
}
return ret;
}
static int
nftnl_expr_hash_snprintf_default(char *buf, size_t size,
const struct nftnl_expr *e)
{
struct nftnl_expr_hash *hash = nftnl_expr_data(e);
int remain = size, offset = 0, ret;
switch (hash->type) {
case NFT_HASH_SYM:
ret =
snprintf(buf, remain, "reg %u = symhash() %% mod %u ",
hash->dreg,
hash->modulus);
SNPRINTF_BUFFER_SIZE(ret, remain, offset);
break;
case NFT_HASH_JENKINS:
default:
ret =
snprintf(buf, remain,
"reg %u = jhash(reg %u, %u, 0x%x) %% mod %u ",
hash->dreg, hash->sreg, hash->len, hash->seed,
hash->modulus);
SNPRINTF_BUFFER_SIZE(ret, remain, offset);
break;
}
if (hash->offset) {
ret = snprintf(buf + offset, remain, "offset %u ",
hash->offset);
SNPRINTF_BUFFER_SIZE(ret, remain, offset);
}
return offset;
}
static int
nftnl_expr_hash_snprintf(char *buf, size_t len, uint32_t type,
uint32_t flags, const struct nftnl_expr *e)
{
switch (type) {
case NFTNL_OUTPUT_DEFAULT:
return nftnl_expr_hash_snprintf_default(buf, len, e);
case NFTNL_OUTPUT_XML:
case NFTNL_OUTPUT_JSON:
default:
break;
}
return -1;
}
struct expr_ops expr_ops_hash = {
.name = "hash",
.alloc_len = sizeof(struct nftnl_expr_hash),
.max_attr = NFTA_HASH_MAX,
.set = nftnl_expr_hash_set,
.get = nftnl_expr_hash_get,
.parse = nftnl_expr_hash_parse,
.build = nftnl_expr_hash_build,
.snprintf = nftnl_expr_hash_snprintf,
};
nftnl_expr_hash
Definition: hash.c:23