expr/synproxy.c
#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_synproxy {
uint16_t mss;
uint8_t wscale;
uint32_t flags;
};
static int nftnl_expr_synproxy_set(struct nftnl_expr *e, uint16_t type,
const void *data, uint32_t data_len)
{
struct nftnl_expr_synproxy *synproxy = nftnl_expr_data(e);
switch(type) {
case NFTNL_EXPR_SYNPROXY_MSS:
memcpy(&synproxy->mss, data, sizeof(synproxy->mss));
break;
case NFTNL_EXPR_SYNPROXY_WSCALE:
memcpy(&synproxy->wscale, data, sizeof(synproxy->wscale));
break;
case NFTNL_EXPR_SYNPROXY_FLAGS:
memcpy(&synproxy->flags, data, sizeof(synproxy->flags));
break;
}
return 0;
}
static const void *
nftnl_expr_synproxy_get(const struct nftnl_expr *e, uint16_t type,
uint32_t *data_len)
{
struct nftnl_expr_synproxy *synproxy = nftnl_expr_data(e);
switch(type) {
case NFTNL_EXPR_SYNPROXY_MSS:
*data_len = sizeof(synproxy->mss);
return &synproxy->mss;
case NFTNL_EXPR_SYNPROXY_WSCALE:
*data_len = sizeof(synproxy->wscale);
return &synproxy->wscale;
case NFTNL_EXPR_SYNPROXY_FLAGS:
*data_len = sizeof(synproxy->flags);
return &synproxy->flags;
}
return NULL;
}
static int nftnl_expr_synproxy_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_SYNPROXY_MAX) < 0)
return MNL_CB_OK;
switch(type) {
case NFTNL_EXPR_SYNPROXY_MSS:
if (mnl_attr_validate(attr, MNL_TYPE_U16) < 0)
abi_breakage();
break;
case NFTNL_EXPR_SYNPROXY_WSCALE:
if (mnl_attr_validate(attr, MNL_TYPE_U8) < 0)
abi_breakage();
break;
case NFTNL_EXPR_SYNPROXY_FLAGS:
if (mnl_attr_validate(attr, MNL_TYPE_U32) < 0)
abi_breakage();
break;
}
tb[type] = attr;
return MNL_CB_OK;
}
static void
nftnl_expr_synproxy_build(struct nlmsghdr *nlh, const struct nftnl_expr *e)
{
struct nftnl_expr_synproxy *synproxy = nftnl_expr_data(e);
if (e->flags & (1 << NFTNL_EXPR_SYNPROXY_MSS))
mnl_attr_put_u16(nlh, NFTNL_EXPR_SYNPROXY_MSS,
htons(synproxy->mss));
if (e->flags & (1 << NFTNL_EXPR_SYNPROXY_WSCALE))
mnl_attr_put_u8(nlh, NFTNL_EXPR_SYNPROXY_WSCALE,
synproxy->wscale);
if (e->flags & (1 << NFTNL_EXPR_SYNPROXY_FLAGS))
mnl_attr_put_u32(nlh, NFTNL_EXPR_SYNPROXY_FLAGS,
htonl(synproxy->flags));
}
static int
nftnl_expr_synproxy_parse(struct nftnl_expr *e, struct nlattr *attr)
{
struct nftnl_expr_synproxy *synproxy = nftnl_expr_data(e);
struct nlattr *tb[NFTA_SYNPROXY_MAX + 1] = {};
if (mnl_attr_parse_nested(attr, nftnl_expr_synproxy_cb, tb) < 0)
return -1;
if (tb[NFTA_SYNPROXY_MSS]) {
synproxy->mss = ntohs(mnl_attr_get_u16(tb[NFTA_SYNPROXY_MSS]));
e->flags |= (1 << NFTNL_EXPR_SYNPROXY_MSS);
}
if (tb[NFTA_SYNPROXY_WSCALE]) {
synproxy->wscale = mnl_attr_get_u8(tb[NFTA_SYNPROXY_WSCALE]);
e->flags |= (1 << NFTNL_EXPR_SYNPROXY_WSCALE);
}
if (tb[NFTA_SYNPROXY_FLAGS]) {
synproxy->flags = ntohl(mnl_attr_get_u32(tb[NFTA_SYNPROXY_FLAGS]));
e->flags |= (1 << NFTNL_EXPR_SYNPROXY_FLAGS);
}
return 0;
}
static int nftnl_expr_synproxy_snprintf_default(char *buf, size_t size,
const struct nftnl_expr *e)
{
struct nftnl_expr_synproxy *synproxy = nftnl_expr_data(e);
int ret, offset = 0, len = size;
if (e->flags & (1 << NFTNL_EXPR_SYNPROXY_MSS) &&
e->flags & (1 << NFTNL_EXPR_SYNPROXY_WSCALE)) {
ret = snprintf(buf, len, "mss %u wscale %u ", synproxy->mss,
synproxy->wscale);
SNPRINTF_BUFFER_SIZE(ret, len, offset);
}
return offset;
}
static int
nftnl_expr_synproxy_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_synproxy_snprintf_default(buf, len, e);
case NFTNL_OUTPUT_XML:
case NFTNL_OUTPUT_JSON:
default:
break;
}
return -1;
}
struct expr_ops expr_ops_synproxy = {
.name = "synproxy",
.alloc_len = sizeof(struct nftnl_expr_synproxy),
.max_attr = NFTA_SYNPROXY_MAX,
.set = nftnl_expr_synproxy_set,
.get = nftnl_expr_synproxy_get,
.parse = nftnl_expr_synproxy_parse,
.build = nftnl_expr_synproxy_build,
.snprintf = nftnl_expr_synproxy_snprintf,
};
nftnl_expr_synproxy
Definition: expr/synproxy.c:13