diff options
Diffstat (limited to 'net/ipv4/netfilter/nft_fib_ipv4.c')
| -rw-r--r-- | net/ipv4/netfilter/nft_fib_ipv4.c | 238 |
1 files changed, 238 insertions, 0 deletions
diff --git a/net/ipv4/netfilter/nft_fib_ipv4.c b/net/ipv4/netfilter/nft_fib_ipv4.c new file mode 100644 index 000000000000..1b49966484b3 --- /dev/null +++ b/net/ipv4/netfilter/nft_fib_ipv4.c @@ -0,0 +1,238 @@ +/* + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#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/netfilter/nf_tables_core.h> +#include <net/netfilter/nf_tables.h> +#include <net/netfilter/nft_fib.h> + +#include <net/ip_fib.h> +#include <net/route.h> + +/* don't try to find route from mcast/bcast/zeronet */ +static __be32 get_saddr(__be32 addr) +{ + if (ipv4_is_multicast(addr) || ipv4_is_lbcast(addr) || + ipv4_is_zeronet(addr)) + return 0; + return addr; +} + +static bool fib4_is_local(const struct sk_buff *skb) +{ + const struct rtable *rt = skb_rtable(skb); + + return rt && (rt->rt_flags & RTCF_LOCAL); +} + +#define DSCP_BITS 0xfc + +void nft_fib4_eval_type(const struct nft_expr *expr, struct nft_regs *regs, + const struct nft_pktinfo *pkt) +{ + const struct nft_fib *priv = nft_expr_priv(expr); + u32 *dst = ®s->data[priv->dreg]; + const struct net_device *dev = NULL; + const struct iphdr *iph; + __be32 addr; + + if (priv->flags & NFTA_FIB_F_IIF) + dev = nft_in(pkt); + else if (priv->flags & NFTA_FIB_F_OIF) + dev = nft_out(pkt); + + iph = ip_hdr(pkt->skb); + if (priv->flags & NFTA_FIB_F_DADDR) + addr = iph->daddr; + else + addr = iph->saddr; + + *dst = inet_dev_addr_type(nft_net(pkt), dev, addr); +} +EXPORT_SYMBOL_GPL(nft_fib4_eval_type); + +static int get_ifindex(const struct net_device *dev) +{ + return dev ? dev->ifindex : 0; +} + +void nft_fib4_eval(const struct nft_expr *expr, struct nft_regs *regs, + const struct nft_pktinfo *pkt) +{ + const struct nft_fib *priv = nft_expr_priv(expr); + u32 *dest = ®s->data[priv->dreg]; + const struct iphdr *iph; + struct fib_result res; + struct flowi4 fl4 = { + .flowi4_scope = RT_SCOPE_UNIVERSE, + .flowi4_iif = LOOPBACK_IFINDEX, + }; + const struct net_device *oif; + struct net_device *found; +#ifdef CONFIG_IP_ROUTE_MULTIPATH + int i; +#endif + + /* + * Do not set flowi4_oif, it restricts results (for example, asking + * for oif 3 will get RTN_UNICAST result even if the daddr exits + * on another interface. + * + * Search results for the desired outinterface instead. + */ + if (priv->flags & NFTA_FIB_F_OIF) + oif = nft_out(pkt); + else if (priv->flags & NFTA_FIB_F_IIF) + oif = nft_in(pkt); + else + oif = NULL; + + if (nft_hook(pkt) == NF_INET_PRE_ROUTING && fib4_is_local(pkt->skb)) { + nft_fib_store_result(dest, priv->result, pkt, LOOPBACK_IFINDEX); + return; + } + + iph = ip_hdr(pkt->skb); + if (ipv4_is_multicast(iph->daddr) && + ipv4_is_zeronet(iph->saddr) && + ipv4_is_local_multicast(iph->daddr)) { + nft_fib_store_result(dest, priv->result, pkt, + get_ifindex(pkt->skb->dev)); + return; + } + + if (priv->flags & NFTA_FIB_F_MARK) + fl4.flowi4_mark = pkt->skb->mark; + + fl4.flowi4_tos = iph->tos & DSCP_BITS; + + if (priv->flags & NFTA_FIB_F_DADDR) { + fl4.daddr = iph->daddr; + fl4.saddr = get_saddr(iph->saddr); + } else { + fl4.daddr = iph->saddr; + fl4.saddr = get_saddr(iph->daddr); + } + + if (fib_lookup(nft_net(pkt), &fl4, &res, FIB_LOOKUP_IGNORE_LINKSTATE)) + return; + + switch (res.type) { + case RTN_UNICAST: + break; + case RTN_LOCAL: /* should not appear here, see fib4_is_local() above */ + return; + default: + break; + } + + if (!oif) { + found = FIB_RES_DEV(res); + goto ok; + } + +#ifdef CONFIG_IP_ROUTE_MULTIPATH + for (i = 0; i < res.fi->fib_nhs; i++) { + struct fib_nh *nh = &res.fi->fib_nh[i]; + + if (nh->nh_dev == oif) { + found = nh->nh_dev; + goto ok; + } + } + return; +#else + found = FIB_RES_DEV(res); + if (found != oif) + return; +#endif +ok: + switch (priv->result) { + case NFT_FIB_RESULT_OIF: + *dest = found->ifindex; + break; + case NFT_FIB_RESULT_OIFNAME: + strncpy((char *)dest, found->name, IFNAMSIZ); + break; + default: + WARN_ON_ONCE(1); + break; + } +} +EXPORT_SYMBOL_GPL(nft_fib4_eval); + +static struct nft_expr_type nft_fib4_type; + +static const struct nft_expr_ops nft_fib4_type_ops = { + .type = &nft_fib4_type, + .size = NFT_EXPR_SIZE(sizeof(struct nft_fib)), + .eval = nft_fib4_eval_type, + .init = nft_fib_init, + .dump = nft_fib_dump, + .validate = nft_fib_validate, +}; + +static const struct nft_expr_ops nft_fib4_ops = { + .type = &nft_fib4_type, + .size = NFT_EXPR_SIZE(sizeof(struct nft_fib)), + .eval = nft_fib4_eval, + .init = nft_fib_init, + .dump = nft_fib_dump, + .validate = nft_fib_validate, +}; + +static const struct nft_expr_ops * +nft_fib4_select_ops(const struct nft_ctx *ctx, + const struct nlattr * const tb[]) +{ + enum nft_fib_result result; + + if (!tb[NFTA_FIB_RESULT]) + return ERR_PTR(-EINVAL); + + result = htonl(nla_get_be32(tb[NFTA_FIB_RESULT])); + + switch (result) { + case NFT_FIB_RESULT_OIF: + return &nft_fib4_ops; + case NFT_FIB_RESULT_OIFNAME: + return &nft_fib4_ops; + case NFT_FIB_RESULT_ADDRTYPE: + return &nft_fib4_type_ops; + default: + return ERR_PTR(-EOPNOTSUPP); + } +} + +static struct nft_expr_type nft_fib4_type __read_mostly = { + .name = "fib", + .select_ops = &nft_fib4_select_ops, + .policy = nft_fib_policy, + .maxattr = NFTA_FIB_MAX, + .family = NFPROTO_IPV4, + .owner = THIS_MODULE, +}; + +static int __init nft_fib4_module_init(void) +{ + return nft_register_expr(&nft_fib4_type); +} + +static void __exit nft_fib4_module_exit(void) +{ + nft_unregister_expr(&nft_fib4_type); +} + +module_init(nft_fib4_module_init); +module_exit(nft_fib4_module_exit); +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Florian Westphal <fw@strlen.de>"); +MODULE_ALIAS_NFT_AF_EXPR(2, "fib"); |