From ba9dda3ab5a865542e69dfe01edb2436857c9420 Mon Sep 17 00:00:00 2001 From: Jozsef Kadlecsik Date: Sat, 7 Jul 2007 22:21:23 -0700 Subject: [NETFILTER]: x_tables: add TRACE target The TRACE target can be used to follow IP and IPv6 packets through the ruleset. Signed-off-by: Jozsef Kadlecsik Signed-off-by: Patrick NcHardy Signed-off-by: David S. Miller --- net/ipv4/ip_output.c | 4 ++ net/ipv4/netfilter/ip_tables.c | 127 ++++++++++++++++++++++++++++++++++++----- 2 files changed, 118 insertions(+), 13 deletions(-) (limited to 'net/ipv4') diff --git a/net/ipv4/ip_output.c b/net/ipv4/ip_output.c index a7dd343d3a0..c9e2b5e6305 100644 --- a/net/ipv4/ip_output.c +++ b/net/ipv4/ip_output.c @@ -399,6 +399,10 @@ static void ip_copy_metadata(struct sk_buff *to, struct sk_buff *from) to->tc_index = from->tc_index; #endif nf_copy(to, from); +#if defined(CONFIG_NETFILTER_XT_TARGET_TRACE) || \ + defined(CONFIG_NETFILTER_XT_TARGET_TRACE_MODULE) + to->nf_trace = from->nf_trace; +#endif #if defined(CONFIG_IP_VS) || defined(CONFIG_IP_VS_MODULE) to->ipvs_property = from->ipvs_property; #endif diff --git a/net/ipv4/netfilter/ip_tables.c b/net/ipv4/netfilter/ip_tables.c index 7962306df58..650ab52e915 100644 --- a/net/ipv4/netfilter/ip_tables.c +++ b/net/ipv4/netfilter/ip_tables.c @@ -204,6 +204,112 @@ get_entry(void *base, unsigned int offset) return (struct ipt_entry *)(base + offset); } +/* All zeroes == unconditional rule. */ +static inline int +unconditional(const struct ipt_ip *ip) +{ + unsigned int i; + + for (i = 0; i < sizeof(*ip)/sizeof(__u32); i++) + if (((__u32 *)ip)[i]) + return 0; + + return 1; +} + +#if defined(CONFIG_NETFILTER_XT_TARGET_TRACE) || \ + defined(CONFIG_NETFILTER_XT_TARGET_TRACE_MODULE) +static const char *hooknames[] = { + [NF_IP_PRE_ROUTING] = "PREROUTING", + [NF_IP_LOCAL_IN] = "INPUT", + [NF_IP_FORWARD] = "FORWARD", + [NF_IP_LOCAL_OUT] = "OUTPUT", + [NF_IP_POST_ROUTING] = "POSTROUTING", +}; + +enum nf_ip_trace_comments { + NF_IP_TRACE_COMMENT_RULE, + NF_IP_TRACE_COMMENT_RETURN, + NF_IP_TRACE_COMMENT_POLICY, +}; + +static const char *comments[] = { + [NF_IP_TRACE_COMMENT_RULE] = "rule", + [NF_IP_TRACE_COMMENT_RETURN] = "return", + [NF_IP_TRACE_COMMENT_POLICY] = "policy", +}; + +static struct nf_loginfo trace_loginfo = { + .type = NF_LOG_TYPE_LOG, + .u = { + .log = { + .level = 4, + .logflags = NF_LOG_MASK, + }, + }, +}; + +static inline int +get_chainname_rulenum(struct ipt_entry *s, struct ipt_entry *e, + char *hookname, char **chainname, + char **comment, unsigned int *rulenum) +{ + struct ipt_standard_target *t = (void *)ipt_get_target(s); + + if (strcmp(t->target.u.kernel.target->name, IPT_ERROR_TARGET) == 0) { + /* Head of user chain: ERROR target with chainname */ + *chainname = t->target.data; + (*rulenum) = 0; + } else if (s == e) { + (*rulenum)++; + + if (s->target_offset == sizeof(struct ipt_entry) + && strcmp(t->target.u.kernel.target->name, + IPT_STANDARD_TARGET) == 0 + && t->verdict < 0 + && unconditional(&s->ip)) { + /* Tail of chains: STANDARD target (return/policy) */ + *comment = *chainname == hookname + ? (char *)comments[NF_IP_TRACE_COMMENT_POLICY] + : (char *)comments[NF_IP_TRACE_COMMENT_RETURN]; + } + return 1; + } else + (*rulenum)++; + + return 0; +} + +static void trace_packet(struct sk_buff *skb, + unsigned int hook, + const struct net_device *in, + const struct net_device *out, + char *tablename, + struct xt_table_info *private, + struct ipt_entry *e) +{ + void *table_base; + struct ipt_entry *root; + char *hookname, *chainname, *comment; + unsigned int rulenum = 0; + + table_base = (void *)private->entries[smp_processor_id()]; + root = get_entry(table_base, private->hook_entry[hook]); + + hookname = chainname = (char *)hooknames[hook]; + comment = (char *)comments[NF_IP_TRACE_COMMENT_RULE]; + + IPT_ENTRY_ITERATE(root, + private->size - private->hook_entry[hook], + get_chainname_rulenum, + e, hookname, &chainname, &comment, &rulenum); + + nf_log_packet(AF_INET, hook, skb, in, out, &trace_loginfo, + "TRACE: %s:%s:%s:%u ", + tablename, chainname, comment, rulenum); +} +#endif + /* Returns one of the generic firewall policies, like NF_ACCEPT. */ unsigned int ipt_do_table(struct sk_buff **pskb, @@ -261,6 +367,14 @@ ipt_do_table(struct sk_buff **pskb, t = ipt_get_target(e); IP_NF_ASSERT(t->u.kernel.target); + +#if defined(CONFIG_NETFILTER_XT_TARGET_TRACE) || \ + defined(CONFIG_NETFILTER_XT_TARGET_TRACE_MODULE) + /* The packet is traced: log it */ + if (unlikely((*pskb)->nf_trace)) + trace_packet(*pskb, hook, in, out, + table->name, private, e); +#endif /* Standard target? */ if (!t->u.kernel.target->target) { int v; @@ -341,19 +455,6 @@ ipt_do_table(struct sk_buff **pskb, #endif } -/* All zeroes == unconditional rule. */ -static inline int -unconditional(const struct ipt_ip *ip) -{ - unsigned int i; - - for (i = 0; i < sizeof(*ip)/sizeof(__u32); i++) - if (((__u32 *)ip)[i]) - return 0; - - return 1; -} - /* Figures out from what hook each rule can be called: returns 0 if there are loops. Puts hook bitmask in comefrom. */ static int -- cgit v1.2.3