1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 *
  4 * Generic part shared by ipv4 and ipv6 backends.
  5 */
  6
  7#include <linux/kernel.h>
  8#include <linux/init.h>
  9#include <linux/module.h>
 10#include <linux/netlink.h>
 11#include <linux/netfilter.h>
 12#include <linux/netfilter/nf_tables.h>
 13#include <net/netfilter/nf_tables_core.h>
 14#include <net/netfilter/nf_tables.h>
 15#include <net/netfilter/nft_fib.h>
 16
 17const struct nla_policy nft_fib_policy[NFTA_FIB_MAX + 1] = {
 18	[NFTA_FIB_DREG]		= { .type = NLA_U32 },
 19	[NFTA_FIB_RESULT]	= { .type = NLA_U32 },
 20	[NFTA_FIB_FLAGS]	= { .type = NLA_U32 },
 21};
 22EXPORT_SYMBOL(nft_fib_policy);
 23
 24#define NFTA_FIB_F_ALL (NFTA_FIB_F_SADDR | NFTA_FIB_F_DADDR | \
 25			NFTA_FIB_F_MARK | NFTA_FIB_F_IIF | NFTA_FIB_F_OIF | \
 26			NFTA_FIB_F_PRESENT)
 27
 28int nft_fib_validate(const struct nft_ctx *ctx, const struct nft_expr *expr,
 29		     const struct nft_data **data)
 30{
 31	const struct nft_fib *priv = nft_expr_priv(expr);
 32	unsigned int hooks;
 33
 34	switch (priv->result) {
 35	case NFT_FIB_RESULT_OIF:
 36	case NFT_FIB_RESULT_OIFNAME:
 37		hooks = (1 << NF_INET_PRE_ROUTING);
 38		break;
 39	case NFT_FIB_RESULT_ADDRTYPE:
 40		if (priv->flags & NFTA_FIB_F_IIF)
 41			hooks = (1 << NF_INET_PRE_ROUTING) |
 42				(1 << NF_INET_LOCAL_IN) |
 43				(1 << NF_INET_FORWARD);
 44		else if (priv->flags & NFTA_FIB_F_OIF)
 45			hooks = (1 << NF_INET_LOCAL_OUT) |
 46				(1 << NF_INET_POST_ROUTING) |
 47				(1 << NF_INET_FORWARD);
 48		else
 49			hooks = (1 << NF_INET_LOCAL_IN) |
 50				(1 << NF_INET_LOCAL_OUT) |
 51				(1 << NF_INET_FORWARD) |
 52				(1 << NF_INET_PRE_ROUTING) |
 53				(1 << NF_INET_POST_ROUTING);
 54
 55		break;
 56	default:
 57		return -EINVAL;
 58	}
 59
 60	return nft_chain_validate_hooks(ctx->chain, hooks);
 61}
 62EXPORT_SYMBOL_GPL(nft_fib_validate);
 63
 64int nft_fib_init(const struct nft_ctx *ctx, const struct nft_expr *expr,
 65		 const struct nlattr * const tb[])
 66{
 67	struct nft_fib *priv = nft_expr_priv(expr);
 68	unsigned int len;
 69	int err;
 70
 71	if (!tb[NFTA_FIB_DREG] || !tb[NFTA_FIB_RESULT] || !tb[NFTA_FIB_FLAGS])
 72		return -EINVAL;
 73
 74	priv->flags = ntohl(nla_get_be32(tb[NFTA_FIB_FLAGS]));
 75
 76	if (priv->flags == 0 || (priv->flags & ~NFTA_FIB_F_ALL))
 77		return -EINVAL;
 78
 79	if ((priv->flags & (NFTA_FIB_F_SADDR | NFTA_FIB_F_DADDR)) ==
 80			   (NFTA_FIB_F_SADDR | NFTA_FIB_F_DADDR))
 81		return -EINVAL;
 82	if ((priv->flags & (NFTA_FIB_F_IIF | NFTA_FIB_F_OIF)) ==
 83			   (NFTA_FIB_F_IIF | NFTA_FIB_F_OIF))
 84		return -EINVAL;
 85	if ((priv->flags & (NFTA_FIB_F_SADDR | NFTA_FIB_F_DADDR)) == 0)
 86		return -EINVAL;
 87
 88	priv->result = ntohl(nla_get_be32(tb[NFTA_FIB_RESULT]));
 89
 90	switch (priv->result) {
 91	case NFT_FIB_RESULT_OIF:
 92		if (priv->flags & NFTA_FIB_F_OIF)
 93			return -EINVAL;
 94		len = sizeof(int);
 95		break;
 96	case NFT_FIB_RESULT_OIFNAME:
 97		if (priv->flags & NFTA_FIB_F_OIF)
 98			return -EINVAL;
 99		len = IFNAMSIZ;
100		break;
101	case NFT_FIB_RESULT_ADDRTYPE:
102		len = sizeof(u32);
103		break;
104	default:
105		return -EINVAL;
106	}
107
108	err = nft_parse_register_store(ctx, tb[NFTA_FIB_DREG], &priv->dreg,
109				       NULL, NFT_DATA_VALUE, len);
110	if (err < 0)
111		return err;
112
113	return 0;
114}
115EXPORT_SYMBOL_GPL(nft_fib_init);
116
117int nft_fib_dump(struct sk_buff *skb, const struct nft_expr *expr)
118{
119	const struct nft_fib *priv = nft_expr_priv(expr);
120
121	if (nft_dump_register(skb, NFTA_FIB_DREG, priv->dreg))
122		return -1;
123
124	if (nla_put_be32(skb, NFTA_FIB_RESULT, htonl(priv->result)))
125		return -1;
126
127	if (nla_put_be32(skb, NFTA_FIB_FLAGS, htonl(priv->flags)))
128		return -1;
129
130	return 0;
131}
132EXPORT_SYMBOL_GPL(nft_fib_dump);
133
134void nft_fib_store_result(void *reg, const struct nft_fib *priv,
135			  const struct net_device *dev)
136{
137	u32 *dreg = reg;
138	int index;
139
140	switch (priv->result) {
141	case NFT_FIB_RESULT_OIF:
142		index = dev ? dev->ifindex : 0;
143		*dreg = (priv->flags & NFTA_FIB_F_PRESENT) ? !!index : index;
144		break;
145	case NFT_FIB_RESULT_OIFNAME:
146		if (priv->flags & NFTA_FIB_F_PRESENT)
147			*dreg = !!dev;
148		else
149			strncpy(reg, dev ? dev->name : "", IFNAMSIZ);
150		break;
151	default:
152		WARN_ON_ONCE(1);
153		*dreg = 0;
154		break;
155	}
156}
157EXPORT_SYMBOL_GPL(nft_fib_store_result);
158
159MODULE_LICENSE("GPL");
160MODULE_AUTHOR("Florian Westphal <fw@strlen.de>");