net/netfilter/nft_meta.c

Source file repositories/reference/linux-study-clean/net/netfilter/nft_meta.c

File Facts

System
Linux kernel
Corpus path
net/netfilter/nft_meta.c
Extension
.c
Size
23153 bytes
Lines
1023
Domain
Networking Core
Bucket
Sockets, Protocols, Packet Path, And Network Policy
Inferred role
Networking Core: exported/initcall integration point
Status
integration implementation candidate

Why This File Exists

Networking stack implementation surface: socket APIs, protocol dispatch, packet flow, routing, filtering, and network namespaces.

Dependency Surface

Detected Declarations

Annotated Snippet

struct nft_secmark {
	u32 secid;
	char *ctx;
};

static const struct nla_policy nft_secmark_policy[NFTA_SECMARK_MAX + 1] = {
	[NFTA_SECMARK_CTX]     = { .type = NLA_STRING, .len = NFT_SECMARK_CTX_MAXLEN },
};

static int nft_secmark_compute_secid(struct nft_secmark *priv)
{
	u32 tmp_secid = 0;
	int err;

	err = security_secctx_to_secid(priv->ctx, strlen(priv->ctx), &tmp_secid);
	if (err)
		return err;

	if (!tmp_secid)
		return -ENOENT;

	err = security_secmark_relabel_packet(tmp_secid);
	if (err)
		return err;

	priv->secid = tmp_secid;
	return 0;
}

static void nft_secmark_obj_eval(struct nft_object *obj, struct nft_regs *regs,
				 const struct nft_pktinfo *pkt)
{
	const struct nft_secmark *priv = nft_obj_data(obj);
	struct sk_buff *skb = pkt->skb;

	skb->secmark = priv->secid;
}

static int nft_secmark_obj_init(const struct nft_ctx *ctx,
				const struct nlattr * const tb[],
				struct nft_object *obj)
{
	struct nft_secmark *priv = nft_obj_data(obj);
	int err;

	if (tb[NFTA_SECMARK_CTX] == NULL)
		return -EINVAL;

	priv->ctx = nla_strdup(tb[NFTA_SECMARK_CTX], GFP_KERNEL_ACCOUNT);
	if (!priv->ctx)
		return -ENOMEM;

	err = nft_secmark_compute_secid(priv);
	if (err) {
		kfree(priv->ctx);
		return err;
	}

	security_secmark_refcount_inc();

	return 0;
}

static int nft_secmark_obj_dump(struct sk_buff *skb, struct nft_object *obj,
				bool reset)
{
	struct nft_secmark *priv = nft_obj_data(obj);
	int err;

	if (nla_put_string(skb, NFTA_SECMARK_CTX, priv->ctx))
		return -1;

	if (reset) {
		err = nft_secmark_compute_secid(priv);
		if (err)
			return err;
	}

	return 0;
}

static void nft_secmark_obj_destroy(const struct nft_ctx *ctx, struct nft_object *obj)
{
	struct nft_secmark *priv = nft_obj_data(obj);

	security_secmark_refcount_dec();

	kfree(priv->ctx);
}

Annotation

Implementation Notes