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[NETFILTER] nfnetlink_log: add sequence numbers for log events 

By using a sequence number for every logged netfilter event, we can
determine from userspace whether logging information was lots somewhere
downstream.

The user has a choice of either having per-instance local sequence
counters, or using a global sequence counter, or both.

Signed-off-by: Harald Welte <laforge@netfilter.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Harald Welte 2006-03-20 17:15:11 -08:00 committed by David S. Miller
parent 5ee956125a
commit 0af5f6c1eb
2 changed files with 52 additions and 0 deletions
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6
include/linux/netfilter/nfnetlink_log.h
View File

@ -47,6 +47,8 @@ enum nfulnl_attr_type {
NFULA_PAYLOAD, /* opaque data payload */
NFULA_PREFIX, /* string prefix */
NFULA_UID, /* user id of socket */
NFULA_SEQ, /* instance-local sequence number */
NFULA_SEQ_GLOBAL, /* global sequence number */
__NFULA_MAX
};
@ -77,6 +79,7 @@ enum nfulnl_attr_config {
NFULA_CFG_NLBUFSIZ, /* u_int32_t buffer size */
NFULA_CFG_TIMEOUT, /* u_int32_t in 1/100 s */
NFULA_CFG_QTHRESH, /* u_int32_t */
NFULA_CFG_FLAGS, /* u_int16_t */
__NFULA_CFG_MAX
};
#define NFULA_CFG_MAX (__NFULA_CFG_MAX -1)
@ -85,4 +88,7 @@ enum nfulnl_attr_config {
#define NFULNL_COPY_META 0x01
#define NFULNL_COPY_PACKET 0x02
#define NFULNL_CFG_F_SEQ 0x0001
#define NFULNL_CFG_F_SEQ_GLOBAL 0x0002
#endif /* _NFNETLINK_LOG_H */

46
net/netfilter/nfnetlink_log.c
View File

@ -11,6 +11,10 @@
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* 2006-01-26 Harald Welte <laforge@netfilter.org>
* - Add optional local and global sequence number to detect lost
* events from userspace
*
*/
#include <linux/module.h>
#include <linux/skbuff.h>
@ -68,11 +72,14 @@ struct nfulnl_instance {
unsigned int nlbufsiz; /* netlink buffer allocation size */
unsigned int qthreshold; /* threshold of the queue */
u_int32_t copy_range;
u_int32_t seq; /* instance-local sequential counter */
u_int16_t group_num; /* number of this queue */
u_int16_t flags;
u_int8_t copy_mode;
};
static DEFINE_RWLOCK(instances_lock);
static atomic_t global_seq;
#define INSTANCE_BUCKETS 16
static struct hlist_head instance_table[INSTANCE_BUCKETS];
@ -310,6 +317,16 @@ nfulnl_set_qthresh(struct nfulnl_instance *inst, u_int32_t qthresh)
return 0;
}
static int
nfulnl_set_flags(struct nfulnl_instance *inst, u_int16_t flags)
{
spin_lock_bh(&inst->lock);
inst->flags = ntohs(flags);
spin_unlock_bh(&inst->lock);
return 0;
}
static struct sk_buff *nfulnl_alloc_skb(unsigned int inst_size,
unsigned int pkt_size)
{
@ -377,6 +394,8 @@ static void nfulnl_timer(unsigned long data)
spin_unlock_bh(&inst->lock);
}
/* This is an inline function, we don't really care about a long
* list of arguments */
static inline int
__build_packet_message(struct nfulnl_instance *inst,
const struct sk_buff *skb,
@ -515,6 +534,17 @@ __build_packet_message(struct nfulnl_instance *inst,
read_unlock_bh(&skb->sk->sk_callback_lock);
}
/* local sequence number */
if (inst->flags & NFULNL_CFG_F_SEQ) {
tmp_uint = htonl(inst->seq++);
NFA_PUT(inst->skb, NFULA_SEQ, sizeof(tmp_uint), &tmp_uint);
}
/* global sequence number */
if (inst->flags & NFULNL_CFG_F_SEQ_GLOBAL) {
tmp_uint = atomic_inc_return(&global_seq);
NFA_PUT(inst->skb, NFULA_SEQ_GLOBAL, sizeof(tmp_uint), &tmp_uint);
}
if (data_len) {
struct nfattr *nfa;
int size = NFA_LENGTH(data_len);
@ -607,6 +637,11 @@ nfulnl_log_packet(unsigned int pf,
spin_lock_bh(&inst->lock);
if (inst->flags & NFULNL_CFG_F_SEQ)
size += NFA_SPACE(sizeof(u_int32_t));
if (inst->flags & NFULNL_CFG_F_SEQ_GLOBAL)
size += NFA_SPACE(sizeof(u_int32_t));
qthreshold = inst->qthreshold;
/* per-rule qthreshold overrides per-instance */
if (qthreshold > li->u.ulog.qthreshold)
@ -736,10 +771,14 @@ static const int nfula_min[NFULA_MAX] = {
[NFULA_TIMESTAMP-1] = sizeof(struct nfulnl_msg_packet_timestamp),
[NFULA_IFINDEX_INDEV-1] = sizeof(u_int32_t),
[NFULA_IFINDEX_OUTDEV-1]= sizeof(u_int32_t),
[NFULA_IFINDEX_PHYSINDEV-1] = sizeof(u_int32_t),
[NFULA_IFINDEX_PHYSOUTDEV-1] = sizeof(u_int32_t),
[NFULA_HWADDR-1] = sizeof(struct nfulnl_msg_packet_hw),
[NFULA_PAYLOAD-1] = 0,
[NFULA_PREFIX-1] = 0,
[NFULA_UID-1] = sizeof(u_int32_t),
[NFULA_SEQ-1] = sizeof(u_int32_t),
[NFULA_SEQ_GLOBAL-1] = sizeof(u_int32_t),
};
static const int nfula_cfg_min[NFULA_CFG_MAX] = {
@ -748,6 +787,7 @@ static const int nfula_cfg_min[NFULA_CFG_MAX] = {
[NFULA_CFG_TIMEOUT-1] = sizeof(u_int32_t),
[NFULA_CFG_QTHRESH-1] = sizeof(u_int32_t),
[NFULA_CFG_NLBUFSIZ-1] = sizeof(u_int32_t),
[NFULA_CFG_FLAGS-1] = sizeof(u_int16_t),
};
static int
@ -859,6 +899,12 @@ nfulnl_recv_config(struct sock *ctnl, struct sk_buff *skb,
nfulnl_set_qthresh(inst, ntohl(qthresh));
}
if (nfula[NFULA_CFG_FLAGS-1]) {
u_int16_t flags =
*(u_int16_t *)NFA_DATA(nfula[NFULA_CFG_FLAGS-1]);
nfulnl_set_flags(inst, ntohl(flags));
}
out_put:
instance_put(inst);
return ret;