From ba9dda3ab5a865542e69dfe01edb2436857c9420 Mon Sep 17 00:00:00 2001 From: Jozsef Kadlecsik Date: Sat, 7 Jul 2007 22:21:23 -0700 Subject: [PATCH] [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 --- include/linux/skbuff.h | 4 +- net/core/skbuff.c | 8 ++ net/ipv4/ip_output.c | 4 + net/ipv4/netfilter/ip_tables.c | 127 +++++++++++++++++++++++++++---- net/ipv6/ip6_output.c | 4 + net/ipv6/netfilter/ip6_tables.c | 128 ++++++++++++++++++++++++++++---- net/netfilter/Kconfig | 12 +++ net/netfilter/Makefile | 1 + net/netfilter/xt_TRACE.c | 53 +++++++++++++ 9 files changed, 314 insertions(+), 27 deletions(-) create mode 100644 net/netfilter/xt_TRACE.c diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index 2d6a14f5f2f..625d73b07ab 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -227,6 +227,7 @@ typedef unsigned char *sk_buff_data_t; * @mark: Generic packet mark * @nfct: Associated connection, if any * @ipvs_property: skbuff is owned by ipvs + * @nf_trace: netfilter packet trace flag * @nfctinfo: Relationship of this skb to the connection * @nfct_reasm: netfilter conntrack re-assembly pointer * @nf_bridge: Saved data about a bridged frame - see br_netfilter.c @@ -278,7 +279,8 @@ struct sk_buff { nfctinfo:3; __u8 pkt_type:3, fclone:2, - ipvs_property:1; + ipvs_property:1, + nf_trace:1; __be16 protocol; void (*destructor)(struct sk_buff *skb); diff --git a/net/core/skbuff.c b/net/core/skbuff.c index 6a41b96b3d3..0583e8498f1 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -428,6 +428,10 @@ struct sk_buff *skb_clone(struct sk_buff *skb, gfp_t gfp_mask) n->destructor = NULL; C(mark); __nf_copy(n, skb); +#if defined(CONFIG_NETFILTER_XT_TARGET_TRACE) || \ + defined(CONFIG_NETFILTER_XT_TARGET_TRACE_MODULE) + C(nf_trace); +#endif #ifdef CONFIG_NET_SCHED C(tc_index); #ifdef CONFIG_NET_CLS_ACT @@ -485,6 +489,10 @@ static void copy_skb_header(struct sk_buff *new, const struct sk_buff *old) new->destructor = NULL; new->mark = old->mark; __nf_copy(new, old); +#if defined(CONFIG_NETFILTER_XT_TARGET_TRACE) || \ + defined(CONFIG_NETFILTER_XT_TARGET_TRACE_MODULE) + new->nf_trace = old->nf_trace; +#endif #if defined(CONFIG_IP_VS) || defined(CONFIG_IP_VS_MODULE) new->ipvs_property = old->ipvs_property; #endif 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 diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c index 31dafaf0b65..50d86e94d9e 100644 --- a/net/ipv6/ip6_output.c +++ b/net/ipv6/ip6_output.c @@ -521,6 +521,10 @@ static void ip6_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 skb_copy_secmark(to, from); } diff --git a/net/ipv6/netfilter/ip6_tables.c b/net/ipv6/netfilter/ip6_tables.c index 7fe4d29708c..4f93b79163a 100644 --- a/net/ipv6/netfilter/ip6_tables.c +++ b/net/ipv6/netfilter/ip6_tables.c @@ -241,6 +241,113 @@ get_entry(void *base, unsigned int offset) return (struct ip6t_entry *)(base + offset); } +/* All zeroes == unconditional rule. */ +static inline int +unconditional(const struct ip6t_ip6 *ipv6) +{ + unsigned int i; + + for (i = 0; i < sizeof(*ipv6); i++) + if (((char *)ipv6)[i]) + break; + + return (i == sizeof(*ipv6)); +} + +#if defined(CONFIG_NETFILTER_XT_TARGET_TRACE) || \ + defined(CONFIG_NETFILTER_XT_TARGET_TRACE_MODULE) +/* This cries for unification! */ +static const char *hooknames[] = { + [NF_IP6_PRE_ROUTING] = "PREROUTING", + [NF_IP6_LOCAL_IN] = "INPUT", + [NF_IP6_FORWARD] = "FORWARD", + [NF_IP6_LOCAL_OUT] = "OUTPUT", + [NF_IP6_POST_ROUTING] = "POSTROUTING", +}; + +enum nf_ip_trace_comments { + NF_IP6_TRACE_COMMENT_RULE, + NF_IP6_TRACE_COMMENT_RETURN, + NF_IP6_TRACE_COMMENT_POLICY, +}; + +static const char *comments[] = { + [NF_IP6_TRACE_COMMENT_RULE] = "rule", + [NF_IP6_TRACE_COMMENT_RETURN] = "return", + [NF_IP6_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 ip6t_entry *s, struct ip6t_entry *e, + char *hookname, char **chainname, + char **comment, unsigned int *rulenum) +{ + struct ip6t_standard_target *t = (void *)ip6t_get_target(s); + + if (strcmp(t->target.u.kernel.target->name, IP6T_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 ip6t_entry) + && strcmp(t->target.u.kernel.target->name, + IP6T_STANDARD_TARGET) == 0 + && t->verdict < 0 + && unconditional(&s->ipv6)) { + /* Tail of chains: STANDARD target (return/policy) */ + *comment = *chainname == hookname + ? (char *)comments[NF_IP6_TRACE_COMMENT_POLICY] + : (char *)comments[NF_IP6_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 ip6t_entry *e) +{ + void *table_base; + struct ip6t_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_IP6_TRACE_COMMENT_RULE]; + + IP6T_ENTRY_ITERATE(root, + private->size - private->hook_entry[hook], + get_chainname_rulenum, + e, hookname, &chainname, &comment, &rulenum); + + nf_log_packet(AF_INET6, 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 ip6t_do_table(struct sk_buff **pskb, @@ -298,6 +405,14 @@ ip6t_do_table(struct sk_buff **pskb, t = ip6t_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; @@ -377,19 +492,6 @@ ip6t_do_table(struct sk_buff **pskb, #endif } -/* All zeroes == unconditional rule. */ -static inline int -unconditional(const struct ip6t_ip6 *ipv6) -{ - unsigned int i; - - for (i = 0; i < sizeof(*ipv6); i++) - if (((char *)ipv6)[i]) - break; - - return (i == sizeof(*ipv6)); -} - /* Figures out from what hook each rule can be called: returns 0 if there are loops. Puts hook bitmask in comefrom. */ static int diff --git a/net/netfilter/Kconfig b/net/netfilter/Kconfig index aa567faa2a8..df5e8dab871 100644 --- a/net/netfilter/Kconfig +++ b/net/netfilter/Kconfig @@ -343,6 +343,18 @@ config NETFILTER_XT_TARGET_NOTRACK If you want to compile it as a module, say M here and read . If unsure, say `N'. +config NETFILTER_XT_TARGET_TRACE + tristate '"TRACE" target support' + depends on NETFILTER_XTABLES + depends on IP_NF_RAW || IP6_NF_RAW + help + The TRACE target allows you to mark packets so that the kernel + will log every rule which match the packets as those traverse + the tables, chains, rules. + + If you want to compile it as a module, say M here and read + . If unsure, say `N'. + config NETFILTER_XT_TARGET_SECMARK tristate '"SECMARK" target support' depends on NETFILTER_XTABLES && NETWORK_SECMARK diff --git a/net/netfilter/Makefile b/net/netfilter/Makefile index 3cf5b9cd6fe..3b792687f00 100644 --- a/net/netfilter/Makefile +++ b/net/netfilter/Makefile @@ -44,6 +44,7 @@ obj-$(CONFIG_NETFILTER_XT_TARGET_MARK) += xt_MARK.o obj-$(CONFIG_NETFILTER_XT_TARGET_NFQUEUE) += xt_NFQUEUE.o obj-$(CONFIG_NETFILTER_XT_TARGET_NFLOG) += xt_NFLOG.o obj-$(CONFIG_NETFILTER_XT_TARGET_NOTRACK) += xt_NOTRACK.o +obj-$(CONFIG_NETFILTER_XT_TARGET_TRACE) += xt_TRACE.o obj-$(CONFIG_NETFILTER_XT_TARGET_SECMARK) += xt_SECMARK.o obj-$(CONFIG_NETFILTER_XT_TARGET_TCPMSS) += xt_TCPMSS.o obj-$(CONFIG_NETFILTER_XT_TARGET_CONNSECMARK) += xt_CONNSECMARK.o diff --git a/net/netfilter/xt_TRACE.c b/net/netfilter/xt_TRACE.c new file mode 100644 index 00000000000..b82fc468034 --- /dev/null +++ b/net/netfilter/xt_TRACE.c @@ -0,0 +1,53 @@ +/* This is a module which is used to mark packets for tracing. + */ +#include +#include + +#include + +MODULE_LICENSE("GPL"); +MODULE_ALIAS("ipt_TRACE"); +MODULE_ALIAS("ip6t_TRACE"); + +static unsigned int +target(struct sk_buff **pskb, + const struct net_device *in, + const struct net_device *out, + unsigned int hooknum, + const struct xt_target *target, + const void *targinfo) +{ + (*pskb)->nf_trace = 1; + return XT_CONTINUE; +} + +static struct xt_target xt_trace_target[] = { + { + .name = "TRACE", + .family = AF_INET, + .target = target, + .table = "raw", + .me = THIS_MODULE, + }, + { + .name = "TRACE", + .family = AF_INET6, + .target = target, + .table = "raw", + .me = THIS_MODULE, + }, +}; + +static int __init xt_trace_init(void) +{ + return xt_register_targets(xt_trace_target, + ARRAY_SIZE(xt_trace_target)); +} + +static void __exit xt_trace_fini(void) +{ + xt_unregister_targets(xt_trace_target, ARRAY_SIZE(xt_trace_target)); +} + +module_init(xt_trace_init); +module_exit(xt_trace_fini); -- 2.41.1