net/netfilter/nft_range.c

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

File Facts

System
Linux kernel
Corpus path
net/netfilter/nft_range.c
Extension
.c
Size
3645 bytes
Lines
150
Domain
Networking Core
Bucket
Sockets, Protocols, Packet Path, And Network Policy
Inferred role
Networking Core: implementation source
Status
source 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_range_expr {
	struct nft_data		data_from;
	struct nft_data		data_to;
	u8			sreg;
	u8			len;
	enum nft_range_ops	op:8;
};

void nft_range_eval(const struct nft_expr *expr,
		    struct nft_regs *regs, const struct nft_pktinfo *pkt)
{
	const struct nft_range_expr *priv = nft_expr_priv(expr);
	int d1, d2;

	d1 = memcmp(&regs->data[priv->sreg], &priv->data_from, priv->len);
	d2 = memcmp(&regs->data[priv->sreg], &priv->data_to, priv->len);
	switch (priv->op) {
	case NFT_RANGE_EQ:
		if (d1 < 0 || d2 > 0)
			regs->verdict.code = NFT_BREAK;
		break;
	case NFT_RANGE_NEQ:
		if (d1 >= 0 && d2 <= 0)
			regs->verdict.code = NFT_BREAK;
		break;
	}
}

static const struct nla_policy nft_range_policy[NFTA_RANGE_MAX + 1] = {
	[NFTA_RANGE_SREG]		= NLA_POLICY_MAX(NLA_BE32, NFT_REG32_MAX),
	[NFTA_RANGE_OP]			= NLA_POLICY_MAX(NLA_BE32, 255),
	[NFTA_RANGE_FROM_DATA]		= { .type = NLA_NESTED },
	[NFTA_RANGE_TO_DATA]		= { .type = NLA_NESTED },
};

static int nft_range_init(const struct nft_ctx *ctx, const struct nft_expr *expr,
			const struct nlattr * const tb[])
{
	struct nft_range_expr *priv = nft_expr_priv(expr);
	struct nft_data_desc desc_from = {
		.type	= NFT_DATA_VALUE,
		.size	= sizeof(priv->data_from),
	};
	struct nft_data_desc desc_to = {
		.type	= NFT_DATA_VALUE,
		.size	= sizeof(priv->data_to),
	};
	int err;
	u32 op;

	if (!tb[NFTA_RANGE_SREG]      ||
	    !tb[NFTA_RANGE_OP]	      ||
	    !tb[NFTA_RANGE_FROM_DATA] ||
	    !tb[NFTA_RANGE_TO_DATA])
		return -EINVAL;

	err = nft_data_init(NULL, &priv->data_from, &desc_from,
			    tb[NFTA_RANGE_FROM_DATA]);
	if (err < 0)
		return err;

	err = nft_data_init(NULL, &priv->data_to, &desc_to,
			    tb[NFTA_RANGE_TO_DATA]);
	if (err < 0)
		goto err1;

	if (desc_from.len != desc_to.len) {
		err = -EINVAL;
		goto err2;
	}

	err = nft_parse_register_load(ctx, tb[NFTA_RANGE_SREG], &priv->sreg,
				      desc_from.len);
	if (err < 0)
		goto err2;

	err = nft_parse_u32_check(tb[NFTA_RANGE_OP], U8_MAX, &op);
	if (err < 0)
		goto err2;

	switch (op) {
	case NFT_RANGE_EQ:
	case NFT_RANGE_NEQ:
		break;
	default:
		err = -EINVAL;
		goto err2;
	}

	priv->op  = op;

Annotation

Implementation Notes