exthdr.c
/*
* (C) 2012-2013 by 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 as published
* by the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This code has been sponsored by Sophos Astaro <http://www.sophos.com>
*/
#include "internal.h"
#include <stdio.h>
#include <string.h>
#include <stdint.h>
#include <limits.h>
#include <arpa/inet.h>
#include <errno.h>
#include <libmnl/libmnl.h>
#include <linux/netfilter/nf_tables.h>
#include <libnftnl/expr.h>
#include <libnftnl/rule.h>
#ifndef IPPROTO_MH
#define IPPROTO_MH 135
#endif
struct nftnl_expr_exthdr {
enum nft_registers dreg;
enum nft_registers sreg;
uint32_t offset;
uint32_t len;
uint8_t type;
uint32_t op;
uint32_t flags;
};
static int
nftnl_expr_exthdr_set(struct nftnl_expr *e, uint16_t type,
const void *data, uint32_t data_len)
{
struct nftnl_expr_exthdr *exthdr = nftnl_expr_data(e);
switch(type) {
case NFTNL_EXPR_EXTHDR_DREG:
memcpy(&exthdr->dreg, data, sizeof(exthdr->dreg));
break;
case NFTNL_EXPR_EXTHDR_TYPE:
memcpy(&exthdr->type, data, sizeof(exthdr->type));
break;
case NFTNL_EXPR_EXTHDR_OFFSET:
memcpy(&exthdr->offset, data, sizeof(exthdr->offset));
break;
case NFTNL_EXPR_EXTHDR_LEN:
memcpy(&exthdr->len, data, sizeof(exthdr->len));
break;
case NFTNL_EXPR_EXTHDR_OP:
memcpy(&exthdr->op, data, sizeof(exthdr->op));
break;
case NFTNL_EXPR_EXTHDR_FLAGS:
memcpy(&exthdr->flags, data, sizeof(exthdr->flags));
break;
case NFTNL_EXPR_EXTHDR_SREG:
memcpy(&exthdr->sreg, data, sizeof(exthdr->sreg));
break;
default:
return -1;
}
return 0;
}
static const void *
nftnl_expr_exthdr_get(const struct nftnl_expr *e, uint16_t type,
uint32_t *data_len)
{
struct nftnl_expr_exthdr *exthdr = nftnl_expr_data(e);
switch(type) {
case NFTNL_EXPR_EXTHDR_DREG:
*data_len = sizeof(exthdr->dreg);
return &exthdr->dreg;
case NFTNL_EXPR_EXTHDR_TYPE:
*data_len = sizeof(exthdr->type);
return &exthdr->type;
case NFTNL_EXPR_EXTHDR_OFFSET:
*data_len = sizeof(exthdr->offset);
return &exthdr->offset;
case NFTNL_EXPR_EXTHDR_LEN:
*data_len = sizeof(exthdr->len);
return &exthdr->len;
case NFTNL_EXPR_EXTHDR_OP:
*data_len = sizeof(exthdr->op);
return &exthdr->op;
case NFTNL_EXPR_EXTHDR_FLAGS:
*data_len = sizeof(exthdr->flags);
return &exthdr->flags;
case NFTNL_EXPR_EXTHDR_SREG:
*data_len = sizeof(exthdr->sreg);
return &exthdr->sreg;
}
return NULL;
}
static int nftnl_expr_exthdr_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_EXTHDR_MAX) < 0)
return MNL_CB_OK;
switch(type) {
case NFTA_EXTHDR_TYPE:
if (mnl_attr_validate(attr, MNL_TYPE_U8) < 0)
abi_breakage();
break;
case NFTA_EXTHDR_DREG:
case NFTA_EXTHDR_SREG:
case NFTA_EXTHDR_OFFSET:
case NFTA_EXTHDR_LEN:
case NFTA_EXTHDR_OP:
case NFTA_EXTHDR_FLAGS:
if (mnl_attr_validate(attr, MNL_TYPE_U32) < 0)
abi_breakage();
break;
}
tb[type] = attr;
return MNL_CB_OK;
}
static void
nftnl_expr_exthdr_build(struct nlmsghdr *nlh, const struct nftnl_expr *e)
{
struct nftnl_expr_exthdr *exthdr = nftnl_expr_data(e);
if (e->flags & (1 << NFTNL_EXPR_EXTHDR_DREG))
mnl_attr_put_u32(nlh, NFTA_EXTHDR_DREG, htonl(exthdr->dreg));
if (e->flags & (1 << NFTNL_EXPR_EXTHDR_SREG))
mnl_attr_put_u32(nlh, NFTA_EXTHDR_SREG, htonl(exthdr->sreg));
if (e->flags & (1 << NFTNL_EXPR_EXTHDR_TYPE))
mnl_attr_put_u8(nlh, NFTA_EXTHDR_TYPE, exthdr->type);
if (e->flags & (1 << NFTNL_EXPR_EXTHDR_OFFSET))
mnl_attr_put_u32(nlh, NFTA_EXTHDR_OFFSET, htonl(exthdr->offset));
if (e->flags & (1 << NFTNL_EXPR_EXTHDR_LEN))
mnl_attr_put_u32(nlh, NFTA_EXTHDR_LEN, htonl(exthdr->len));
if (e->flags & (1 << NFTNL_EXPR_EXTHDR_OP))
mnl_attr_put_u32(nlh, NFTA_EXTHDR_OP, htonl(exthdr->op));
if (e->flags & (1 << NFTNL_EXPR_EXTHDR_FLAGS))
mnl_attr_put_u32(nlh, NFTA_EXTHDR_FLAGS, htonl(exthdr->flags));
}
static int
nftnl_expr_exthdr_parse(struct nftnl_expr *e, struct nlattr *attr)
{
struct nftnl_expr_exthdr *exthdr = nftnl_expr_data(e);
struct nlattr *tb[NFTA_EXTHDR_MAX+1] = {};
if (mnl_attr_parse_nested(attr, nftnl_expr_exthdr_cb, tb) < 0)
return -1;
if (tb[NFTA_EXTHDR_DREG]) {
exthdr->dreg = ntohl(mnl_attr_get_u32(tb[NFTA_EXTHDR_DREG]));
e->flags |= (1 << NFTNL_EXPR_EXTHDR_DREG);
}
if (tb[NFTA_EXTHDR_SREG]) {
exthdr->sreg = ntohl(mnl_attr_get_u32(tb[NFTA_EXTHDR_SREG]));
e->flags |= (1 << NFTNL_EXPR_EXTHDR_SREG);
}
if (tb[NFTA_EXTHDR_TYPE]) {
exthdr->type = mnl_attr_get_u8(tb[NFTA_EXTHDR_TYPE]);
e->flags |= (1 << NFTNL_EXPR_EXTHDR_TYPE);
}
if (tb[NFTA_EXTHDR_OFFSET]) {
exthdr->offset = ntohl(mnl_attr_get_u32(tb[NFTA_EXTHDR_OFFSET]));
e->flags |= (1 << NFTNL_EXPR_EXTHDR_OFFSET);
}
if (tb[NFTA_EXTHDR_LEN]) {
exthdr->len = ntohl(mnl_attr_get_u32(tb[NFTA_EXTHDR_LEN]));
e->flags |= (1 << NFTNL_EXPR_EXTHDR_LEN);
}
if (tb[NFTA_EXTHDR_OP]) {
exthdr->op = ntohl(mnl_attr_get_u32(tb[NFTA_EXTHDR_OP]));
e->flags |= (1 << NFTNL_EXPR_EXTHDR_OP);
}
if (tb[NFTA_EXTHDR_FLAGS]) {
exthdr->flags = ntohl(mnl_attr_get_u32(tb[NFTA_EXTHDR_FLAGS]));
e->flags |= (1 << NFTNL_EXPR_EXTHDR_FLAGS);
}
return 0;
}
static const char *op2str(uint8_t op)
{
switch (op) {
case NFT_EXTHDR_OP_TCPOPT:
return " tcpopt";
case NFT_EXTHDR_OP_IPV6:
return " ipv6";
case NFT_EXTHDR_OP_IPV4:
return " ipv4";
default:
return "";
}
}
static inline int str2exthdr_op(const char* str)
{
if (!strcmp(str, "tcpopt"))
return NFT_EXTHDR_OP_TCPOPT;
if (!strcmp(str, "ipv4"))
return NFT_EXTHDR_OP_IPV4;
/* if str == "ipv6" or anything else */
return NFT_EXTHDR_OP_IPV6;
}
static inline int str2exthdr_type(const char *str)
{
if (strcmp(str, "hopopts") == 0)
return IPPROTO_HOPOPTS;
else if (strcmp(str, "routing") == 0)
return IPPROTO_ROUTING;
else if (strcmp(str, "fragment") == 0)
return IPPROTO_FRAGMENT;
else if (strcmp(str, "dstopts") == 0)
return IPPROTO_DSTOPTS;
else if (strcmp(str, "mh") == 0)
return IPPROTO_MH;
return -1;
}
static int nftnl_expr_exthdr_snprintf_default(char *buf, size_t len,
const struct nftnl_expr *e)
{
struct nftnl_expr_exthdr *exthdr = nftnl_expr_data(e);
if (e->flags & (1 << NFTNL_EXPR_EXTHDR_DREG))
return snprintf(buf, len, "load%s %ub @ %u + %u%s => reg %u ",
op2str(exthdr->op), exthdr->len, exthdr->type,
exthdr->offset,
exthdr->flags & NFT_EXTHDR_F_PRESENT ? " present" : "",
exthdr->dreg);
else
return snprintf(buf, len, "write%s reg %u => %ub @ %u + %u ",
op2str(exthdr->op), exthdr->sreg, exthdr->len, exthdr->type,
exthdr->offset);
}
static int
nftnl_expr_exthdr_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_exthdr_snprintf_default(buf, len, e);
case NFTNL_OUTPUT_XML:
case NFTNL_OUTPUT_JSON:
default:
break;
}
return -1;
}
struct expr_ops expr_ops_exthdr = {
.name = "exthdr",
.alloc_len = sizeof(struct nftnl_expr_exthdr),
.max_attr = NFTA_EXTHDR_MAX,
.set = nftnl_expr_exthdr_set,
.get = nftnl_expr_exthdr_get,
.parse = nftnl_expr_exthdr_parse,
.build = nftnl_expr_exthdr_build,
.snprintf = nftnl_expr_exthdr_snprintf,
};
nftnl_expr_exthdr
Definition: exthdr.c:31