#include <linux/audit.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/netlink.h>
#include <linux/netfilter.h>
#include <linux/netfilter/nf_tables.h>
#include <net/ipv6.h>
#include <net/ip.h>
#include <net/netfilter/nf_tables.h>
#include <net/netfilter/nf_log.h>
#include <linux/netdevice.h>
static const char *nft_log_null_prefix = "";
struct nft_log {
struct nf_loginfo loginfo;
char *prefix;
};
static void nft_log_eval_audit(const struct nft_pktinfo *pkt)
{
struct sk_buff *skb = pkt->skb;
struct audit_buffer *ab;
if (!audit_enabled)
return;
ab = audit_log_start(NULL, GFP_ATOMIC, AUDIT_NETFILTER_PKT);
if (!ab)
return;
audit_log_format(ab, "mark=%#x", skb->mark);
audit_log_nf_skb(ab, skb, nft_pf(pkt));
audit_log_end(ab);
}
static void nft_log_eval(const struct nft_expr *expr,
struct nft_regs *regs,
const struct nft_pktinfo *pkt)
{
const struct nft_log *priv = nft_expr_priv(expr);
if (priv->loginfo.type == NF_LOG_TYPE_LOG &&
priv->loginfo.u.log.level == NFT_LOGLEVEL_AUDIT) {
nft_log_eval_audit(pkt);
return;
}
nf_log_packet(nft_net(pkt), nft_pf(pkt), nft_hook(pkt), pkt->skb,
nft_in(pkt), nft_out(pkt), &priv->loginfo, "%s",
priv->prefix);
}
static const struct nla_policy nft_log_policy[NFTA_LOG_MAX + 1] = {
[NFTA_LOG_GROUP] = { .type = NLA_U16 },
[NFTA_LOG_PREFIX] = { .type = NLA_STRING,
.len = NF_LOG_PREFIXLEN - 1 },
[NFTA_LOG_SNAPLEN] = { .type = NLA_U32 },
[NFTA_LOG_QTHRESHOLD] = { .type = NLA_U16 },
[NFTA_LOG_LEVEL] = { .type = NLA_U32 },
[NFTA_LOG_FLAGS] = { .type = NLA_U32 },
};
static int nft_log_modprobe(struct net *net, enum nf_log_type t)
{
switch (t) {
case NF_LOG_TYPE_LOG:
return nft_request_module(net, "%s", "nf_log_syslog");
case NF_LOG_TYPE_ULOG:
return nft_request_module(net, "%s", "nfnetlink_log");
case NF_LOG_TYPE_MAX:
break;
}
return -ENOENT;
}
static int nft_log_init(const struct nft_ctx *ctx,
const struct nft_expr *expr,
const struct nlattr * const tb[])
{
struct nft_log *priv = nft_expr_priv(expr);
struct nf_loginfo *li = &priv->loginfo;
const struct nlattr *nla;
int err;
li->type = NF_LOG_TYPE_LOG;
if (tb[NFTA_LOG_LEVEL] != NULL &&
tb[NFTA_LOG_GROUP] != NULL)
return -EINVAL;
if (tb[NFTA_LOG_GROUP] != NULL) {
li->type = NF_LOG_TYPE_ULOG;
if (tb[NFTA_LOG_FLAGS] != NULL)
return -EINVAL;
}
nla = tb[NFTA_LOG_PREFIX];
if (nla != NULL) {
priv->prefix = kmalloc(nla_len(nla) + 1, GFP_KERNEL_ACCOUNT);
if (priv->prefix == NULL)
return -ENOMEM;
nla_strscpy(priv->prefix, nla, nla_len(nla) + 1);
} else {
priv->prefix = (char *)nft_log_null_prefix;
}
switch (li->type) {
case NF_LOG_TYPE_LOG:
if (tb[NFTA_LOG_LEVEL] != NULL) {
li->u.log.level =
ntohl(nla_get_be32(tb[NFTA_LOG_LEVEL]));
} else {
li->u.log.level = NFT_LOGLEVEL_WARNING;
}
if (li->u.log.level > NFT_LOGLEVEL_AUDIT) {
err = -EINVAL;
goto err1;
}
if (tb[NFTA_LOG_FLAGS] != NULL) {
li->u.log.logflags =
ntohl(nla_get_be32(tb[NFTA_LOG_FLAGS]));
if (li->u.log.logflags & ~NF_LOG_MASK) {
err = -EINVAL;
goto err1;
}
}
break;
case NF_LOG_TYPE_ULOG:
li->u.ulog.group = ntohs(nla_get_be16(tb[NFTA_LOG_GROUP]));
if (tb[NFTA_LOG_SNAPLEN] != NULL) {
li->u.ulog.flags |= NF_LOG_F_COPY_LEN;
li->u.ulog.copy_len =
ntohl(nla_get_be32(tb[NFTA_LOG_SNAPLEN]));
}
if (tb[NFTA_LOG_QTHRESHOLD] != NULL) {
li->u.ulog.qthreshold =
ntohs(nla_get_be16(tb[NFTA_LOG_QTHRESHOLD]));
}
break;
}
if (li->u.log.level == NFT_LOGLEVEL_AUDIT)
return 0;
err = nf_logger_find_get(ctx->family, li->type);
if (err < 0) {
if (nft_log_modprobe(ctx->net, li->type) == -EAGAIN)
err = -EAGAIN;
goto err1;
}
return 0;
err1:
if (priv->prefix != nft_log_null_prefix)
kfree(priv->prefix);
return err;
}
static void nft_log_destroy(const struct nft_ctx *ctx,
const struct nft_expr *expr)
{
struct nft_log *priv = nft_expr_priv(expr);
struct nf_loginfo *li = &priv->loginfo;
if (priv->prefix != nft_log_null_prefix)
kfree(priv->prefix);
if (li->u.log.level == NFT_LOGLEVEL_AUDIT)
return;
nf_logger_put(ctx->family, li->type);
}
static int nft_log_dump(struct sk_buff *skb,
const struct nft_expr *expr, bool reset)
{
const struct nft_log *priv = nft_expr_priv(expr);
const struct nf_loginfo *li = &priv->loginfo;
if (priv->prefix != nft_log_null_prefix)
if (nla_put_string(skb, NFTA_LOG_PREFIX, priv->prefix))
goto nla_put_failure;
switch (li->type) {
case NF_LOG_TYPE_LOG:
if (nla_put_be32(skb, NFTA_LOG_LEVEL, htonl(li->u.log.level)))
goto nla_put_failure;
if (li->u.log.logflags) {
if (nla_put_be32(skb, NFTA_LOG_FLAGS,
htonl(li->u.log.logflags)))
goto nla_put_failure;
}
break;
case NF_LOG_TYPE_ULOG:
if (nla_put_be16(skb, NFTA_LOG_GROUP, htons(li->u.ulog.group)))
goto nla_put_failure;
if (li->u.ulog.flags & NF_LOG_F_COPY_LEN) {
if (nla_put_be32(skb, NFTA_LOG_SNAPLEN,
htonl(li->u.ulog.copy_len)))
goto nla_put_failure;
}
if (li->u.ulog.qthreshold) {
if (nla_put_be16(skb, NFTA_LOG_QTHRESHOLD,
htons(li->u.ulog.qthreshold)))
goto nla_put_failure;
}
break;
}
return 0;
nla_put_failure:
return -1;
}
static struct nft_expr_type nft_log_type;
static const struct nft_expr_ops nft_log_ops = {
.type = &nft_log_type,
.size = NFT_EXPR_SIZE(sizeof(struct nft_log)),
.eval = nft_log_eval,
.init = nft_log_init,
.destroy = nft_log_destroy,
.dump = nft_log_dump,
.reduce = NFT_REDUCE_READONLY,
};
static struct nft_expr_type nft_log_type __read_mostly = {
.name = "log",
.ops = &nft_log_ops,
.policy = nft_log_policy,
.maxattr = NFTA_LOG_MAX,
.owner = THIS_MODULE,
};
static int __init nft_log_module_init(void)
{
return nft_register_expr(&nft_log_type);
}
static void __exit nft_log_module_exit(void)
{
nft_unregister_expr(&nft_log_type);
}
module_init(nft_log_module_init);
module_exit(nft_log_module_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
MODULE_ALIAS_NFT_EXPR("log");
MODULE_DESCRIPTION("Netfilter nf_tables log module");
