diff options
Diffstat (limited to 'net/netfilter/nf_tables_core.c')
-rw-r--r-- | net/netfilter/nf_tables_core.c | 270 |
1 files changed, 270 insertions, 0 deletions
diff --git a/net/netfilter/nf_tables_core.c b/net/netfilter/nf_tables_core.c new file mode 100644 index 000000000000..cb9e685caae1 --- /dev/null +++ b/net/netfilter/nf_tables_core.c @@ -0,0 +1,270 @@ +/* + * Copyright (c) 2008 Patrick McHardy <kaber@trash.net> + * + * 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. + * + * Development of this code funded by Astaro AG (http://www.astaro.com/) + */ + +#include <linux/module.h> +#include <linux/init.h> +#include <linux/list.h> +#include <linux/rculist.h> +#include <linux/skbuff.h> +#include <linux/netlink.h> +#include <linux/netfilter.h> +#include <linux/netfilter/nfnetlink.h> +#include <linux/netfilter/nf_tables.h> +#include <net/netfilter/nf_tables_core.h> +#include <net/netfilter/nf_tables.h> +#include <net/netfilter/nf_log.h> + +static void nft_cmp_fast_eval(const struct nft_expr *expr, + struct nft_data data[NFT_REG_MAX + 1]) +{ + const struct nft_cmp_fast_expr *priv = nft_expr_priv(expr); + u32 mask; + + mask = ~0U >> (sizeof(priv->data) * BITS_PER_BYTE - priv->len); + if ((data[priv->sreg].data[0] & mask) == priv->data) + return; + data[NFT_REG_VERDICT].verdict = NFT_BREAK; +} + +static bool nft_payload_fast_eval(const struct nft_expr *expr, + struct nft_data data[NFT_REG_MAX + 1], + const struct nft_pktinfo *pkt) +{ + const struct nft_payload *priv = nft_expr_priv(expr); + const struct sk_buff *skb = pkt->skb; + struct nft_data *dest = &data[priv->dreg]; + unsigned char *ptr; + + if (priv->base == NFT_PAYLOAD_NETWORK_HEADER) + ptr = skb_network_header(skb); + else + ptr = skb_network_header(skb) + pkt->xt.thoff; + + ptr += priv->offset; + + if (unlikely(ptr + priv->len >= skb_tail_pointer(skb))) + return false; + + if (priv->len == 2) + *(u16 *)dest->data = *(u16 *)ptr; + else if (priv->len == 4) + *(u32 *)dest->data = *(u32 *)ptr; + else + *(u8 *)dest->data = *(u8 *)ptr; + return true; +} + +struct nft_jumpstack { + const struct nft_chain *chain; + const struct nft_rule *rule; + int rulenum; +}; + +static inline void +nft_chain_stats(const struct nft_chain *this, const struct nft_pktinfo *pkt, + struct nft_jumpstack *jumpstack, unsigned int stackptr) +{ + struct nft_stats __percpu *stats; + const struct nft_chain *chain = stackptr ? jumpstack[0].chain : this; + + rcu_read_lock_bh(); + stats = rcu_dereference(nft_base_chain(chain)->stats); + __this_cpu_inc(stats->pkts); + __this_cpu_add(stats->bytes, pkt->skb->len); + rcu_read_unlock_bh(); +} + +enum nft_trace { + NFT_TRACE_RULE, + NFT_TRACE_RETURN, + NFT_TRACE_POLICY, +}; + +static const char *const comments[] = { + [NFT_TRACE_RULE] = "rule", + [NFT_TRACE_RETURN] = "return", + [NFT_TRACE_POLICY] = "policy", +}; + +static struct nf_loginfo trace_loginfo = { + .type = NF_LOG_TYPE_LOG, + .u = { + .log = { + .level = 4, + .logflags = NF_LOG_MASK, + }, + }, +}; + +static inline void nft_trace_packet(const struct nft_pktinfo *pkt, + const struct nft_chain *chain, + int rulenum, enum nft_trace type) +{ + struct net *net = dev_net(pkt->in ? pkt->in : pkt->out); + + nf_log_packet(net, pkt->xt.family, pkt->hooknum, pkt->skb, pkt->in, + pkt->out, &trace_loginfo, "TRACE: %s:%s:%s:%u ", + chain->table->name, chain->name, comments[type], + rulenum); +} + +unsigned int +nft_do_chain_pktinfo(struct nft_pktinfo *pkt, const struct nf_hook_ops *ops) +{ + const struct nft_chain *chain = ops->priv; + const struct nft_rule *rule; + const struct nft_expr *expr, *last; + struct nft_data data[NFT_REG_MAX + 1]; + unsigned int stackptr = 0; + struct nft_jumpstack jumpstack[NFT_JUMP_STACK_SIZE]; + int rulenum = 0; + /* + * Cache cursor to avoid problems in case that the cursor is updated + * while traversing the ruleset. + */ + unsigned int gencursor = ACCESS_ONCE(chain->net->nft.gencursor); + +do_chain: + rule = list_entry(&chain->rules, struct nft_rule, list); +next_rule: + data[NFT_REG_VERDICT].verdict = NFT_CONTINUE; + list_for_each_entry_continue_rcu(rule, &chain->rules, list) { + + /* This rule is not active, skip. */ + if (unlikely(rule->genmask & (1 << gencursor))) + continue; + + rulenum++; + + nft_rule_for_each_expr(expr, last, rule) { + if (expr->ops == &nft_cmp_fast_ops) + nft_cmp_fast_eval(expr, data); + else if (expr->ops != &nft_payload_fast_ops || + !nft_payload_fast_eval(expr, data, pkt)) + expr->ops->eval(expr, data, pkt); + + if (data[NFT_REG_VERDICT].verdict != NFT_CONTINUE) + break; + } + + switch (data[NFT_REG_VERDICT].verdict) { + case NFT_BREAK: + data[NFT_REG_VERDICT].verdict = NFT_CONTINUE; + /* fall through */ + case NFT_CONTINUE: + continue; + } + break; + } + + switch (data[NFT_REG_VERDICT].verdict) { + case NF_ACCEPT: + case NF_DROP: + case NF_QUEUE: + if (unlikely(pkt->skb->nf_trace)) + nft_trace_packet(pkt, chain, rulenum, NFT_TRACE_RULE); + + return data[NFT_REG_VERDICT].verdict; + case NFT_JUMP: + if (unlikely(pkt->skb->nf_trace)) + nft_trace_packet(pkt, chain, rulenum, NFT_TRACE_RULE); + + BUG_ON(stackptr >= NFT_JUMP_STACK_SIZE); + jumpstack[stackptr].chain = chain; + jumpstack[stackptr].rule = rule; + jumpstack[stackptr].rulenum = rulenum; + stackptr++; + /* fall through */ + case NFT_GOTO: + chain = data[NFT_REG_VERDICT].chain; + goto do_chain; + case NFT_RETURN: + if (unlikely(pkt->skb->nf_trace)) + nft_trace_packet(pkt, chain, rulenum, NFT_TRACE_RETURN); + + /* fall through */ + case NFT_CONTINUE: + break; + default: + WARN_ON(1); + } + + if (stackptr > 0) { + if (unlikely(pkt->skb->nf_trace)) + nft_trace_packet(pkt, chain, ++rulenum, NFT_TRACE_RETURN); + + stackptr--; + chain = jumpstack[stackptr].chain; + rule = jumpstack[stackptr].rule; + rulenum = jumpstack[stackptr].rulenum; + goto next_rule; + } + nft_chain_stats(chain, pkt, jumpstack, stackptr); + + if (unlikely(pkt->skb->nf_trace)) + nft_trace_packet(pkt, chain, ++rulenum, NFT_TRACE_POLICY); + + return nft_base_chain(chain)->policy; +} +EXPORT_SYMBOL_GPL(nft_do_chain_pktinfo); + +int __init nf_tables_core_module_init(void) +{ + int err; + + err = nft_immediate_module_init(); + if (err < 0) + goto err1; + + err = nft_cmp_module_init(); + if (err < 0) + goto err2; + + err = nft_lookup_module_init(); + if (err < 0) + goto err3; + + err = nft_bitwise_module_init(); + if (err < 0) + goto err4; + + err = nft_byteorder_module_init(); + if (err < 0) + goto err5; + + err = nft_payload_module_init(); + if (err < 0) + goto err6; + + return 0; + +err6: + nft_byteorder_module_exit(); +err5: + nft_bitwise_module_exit(); +err4: + nft_lookup_module_exit(); +err3: + nft_cmp_module_exit(); +err2: + nft_immediate_module_exit(); +err1: + return err; +} + +void nf_tables_core_module_exit(void) +{ + nft_payload_module_exit(); + nft_byteorder_module_exit(); + nft_bitwise_module_exit(); + nft_lookup_module_exit(); + nft_cmp_module_exit(); + nft_immediate_module_exit(); +} |