freebsd-dev/sys/netgraph/netflow/netflow.c
Gleb Smirnoff d1240630b3 Expire aged flows in normal expiry thread. This fixes the problem, when
a node disconnected from all sources of traffic never purges its cache.
2005-02-05 10:00:04 +00:00

742 lines
19 KiB
C

/*-
* Copyright (c) 2004 Gleb Smirnoff <glebius@FreeBSD.org>
* Copyright (c) 2001-2003 Roman V. Palagin <romanp@unshadow.net>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $SourceForge: netflow.c,v 1.41 2004/09/05 11:41:10 glebius Exp $
*/
static const char rcs_id[] =
"@(#) $FreeBSD$";
#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/limits.h>
#include <sys/mbuf.h>
#include <sys/syslog.h>
#include <sys/systm.h>
#include <sys/socket.h>
#include <net/if.h>
#include <net/if_var.h>
#include <net/if_dl.h>
#include <net/route.h>
#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#include <netinet/tcp.h>
#include <netinet/udp.h>
#include <netgraph/ng_message.h>
#include <netgraph/netgraph.h>
#include <netgraph/netflow/netflow.h>
#include <netgraph/netflow/ng_netflow.h>
#define NBUCKETS (4096) /* must be power of 2 */
/* This hash is for TCP or UDP packets */
#define FULL_HASH(addr1,addr2,port1,port2)\
(((addr1 >> 16) ^ \
(addr2 & 0x00FF) ^ \
((port1 ^ port2) << 8) )& \
(NBUCKETS - 1))
/* This hash for all other IP packets */
#define ADDR_HASH(addr1,addr2)\
(((addr1 >> 16) ^ \
(addr2 & 0x00FF) )& \
(NBUCKETS - 1))
/* Macros to shorten logical constructions */
/* XXX: priv must exist in namespace */
#define INACTIVE(fle) (time_uptime - fle->f.last > priv->info.nfinfo_inact_t)
#define AGED(fle) (time_uptime - fle->f.first > priv->info.nfinfo_act_t)
#define ISFREE(fle) (fle->f.packets == 0)
/*
* 4 is a magical number: statistically number of 4-packet flows is
* bigger than 5,6,7...-packet flows by an order of magnitude. Most UDP/ICMP
* scans are 1 packet (~ 90% of flow cache). TCP scans are 2-packet in case
* of reachable host and 4-packet otherwise.
*/
#define SMALL(fle) (fle->f.packets <= 4)
MALLOC_DECLARE(M_NETFLOW);
MALLOC_DEFINE(M_NETFLOW, "NetFlow", "flow cache");
static int export_add(priv_p , struct flow_entry *);
static int export_send(priv_p );
/* Generate hash for a given flow record */
static __inline uint32_t
ip_hash(struct flow_rec *r)
{
switch (r->r_ip_p) {
case IPPROTO_TCP:
case IPPROTO_UDP:
return FULL_HASH(r->r_src.s_addr, r->r_dst.s_addr,
r->r_sport, r->r_dport);
default:
return ADDR_HASH(r->r_src.s_addr, r->r_dst.s_addr);
}
}
/* Lookup for record in given slot */
static __inline struct flow_entry *
hash_lookup(struct flow_hash_entry *h, int slot, struct flow_rec *r)
{
struct flow_entry *fle;
LIST_FOREACH(fle, &(h[slot].head), fle_hash)
if (bcmp(r, &fle->f.r, sizeof(struct flow_rec)) == 0)
return (fle);
return (NULL);
}
/* Get a flow entry from free list */
static __inline struct flow_entry *
alloc_flow(priv_p priv, int *flows)
{
register struct flow_entry *fle;
mtx_lock(&priv->free_mtx);
if (SLIST_EMPTY(&priv->free_list)) {
mtx_unlock(&priv->free_mtx);
return(NULL);
}
fle = SLIST_FIRST(&priv->free_list);
SLIST_REMOVE_HEAD(&priv->free_list, fle_free);
priv->info.nfinfo_used++;
priv->info.nfinfo_free--;
if (flows != NULL)
*flows = priv->info.nfinfo_used;
mtx_unlock(&priv->free_mtx);
return (fle);
}
/* Insert flow entry into a free list. */
static __inline int
free_flow(priv_p priv, struct flow_entry *fle)
{
int flows;
mtx_lock(&priv->free_mtx);
fle->f.packets = 0;
SLIST_INSERT_HEAD(&priv->free_list, fle, fle_free);
flows = priv->info.nfinfo_used--;
priv->info.nfinfo_free++;
mtx_unlock(&priv->free_mtx);
return flows;
}
#define NGNF_GETUSED(priv, rval) do { \
mtx_lock(&priv->free_mtx); \
rval = priv->info.nfinfo_used; \
mtx_unlock(&priv->free_mtx); \
} while (0)
/* Insert flow entry into expire list. */
/* XXX: Flow must be detached from work queue, but not from cache */
static __inline void
expire_flow(priv_p priv, struct flow_entry *fle)
{
mtx_assert(&priv->work_mtx, MA_OWNED);
LIST_REMOVE(fle, fle_hash);
mtx_lock(&priv->expire_mtx);
SLIST_INSERT_HEAD(&priv->expire_list, fle, fle_free);
mtx_unlock(&priv->expire_mtx);
}
/* Get a snapshot of node statistics */
void
ng_netflow_copyinfo(priv_p priv, struct ng_netflow_info *i)
{
mtx_lock(&priv->free_mtx);
memcpy((void *)i, (void *)&priv->info, sizeof(priv->info));
mtx_unlock(&priv->free_mtx);
}
/* Calculate number of bits in netmask */
#define g21 0x55555555ul /* = 0101_0101_0101_0101_0101_0101_0101_0101 */
#define g22 0x33333333ul /* = 0011_0011_0011_0011_0011_0011_0011_0011 */
#define g23 0x0f0f0f0ful /* = 0000_1111_0000_1111_0000_1111_0000_1111 */
static __inline u_char
bit_count(uint32_t v)
{
v = (v & g21) + ((v >> 1) & g21);
v = (v & g22) + ((v >> 2) & g22);
v = (v + (v >> 4)) & g23;
return (v + (v >> 8) + (v >> 16) + (v >> 24)) & 0x3f;
}
/*
* Insert a record into defined slot.
*
* First we get for us a free flow entry, then fill in all
* possible fields in it. Then obtain lock on flow cache
* and insert flow entry.
*/
static __inline int
hash_insert(priv_p priv, int slot, struct flow_rec *r, int plen)
{
struct flow_hash_entry *h = priv->hash;
struct flow_entry *fle;
struct route ro;
struct sockaddr_in *sin;
fle = alloc_flow(priv, NULL);
if (fle == NULL)
return (ENOMEM);
/*
* Now fle is totally ours. It is detached from all lists,
* we can safely edit it.
*/
bcopy(r, &fle->f.r, sizeof(struct flow_rec));
fle->f.bytes = plen;
fle->f.packets = 1;
priv->info.nfinfo_bytes += plen;
fle->f.first = fle->f.last = time_uptime;
/*
* First we do route table lookup on destination address. So we can
* fill in out_ifx, dst_mask, nexthop, and dst_as in future releases.
*/
bzero((caddr_t)&ro, sizeof(ro));
sin = (struct sockaddr_in *)&ro.ro_dst;
sin->sin_len = sizeof(*sin);
sin->sin_family = AF_INET;
sin->sin_addr = fle->f.r.r_dst;
rtalloc_ign(&ro, RTF_CLONING);
if (ro.ro_rt != NULL) {
struct rtentry *rt = ro.ro_rt;
fle->f.fle_o_ifx = rt->rt_ifp->if_index;
if (rt->rt_flags & RTF_GATEWAY &&
rt->rt_gateway->sa_family == AF_INET)
fle->f.next_hop =
((struct sockaddr_in *)(rt->rt_gateway))->sin_addr;
if (rt_mask(rt))
fle->f.dst_mask =
bit_count(((struct sockaddr_in *)rt_mask(rt))->sin_addr.s_addr);
else if (rt->rt_flags & RTF_HOST)
/* Give up. We can't determine mask :( */
fle->f.dst_mask = 32;
RTFREE(ro.ro_rt);
}
/* Do route lookup on source address, to fill in src_mask. */
bzero((caddr_t)&ro, sizeof(ro));
sin = (struct sockaddr_in *)&ro.ro_dst;
sin->sin_len = sizeof(*sin);
sin->sin_family = AF_INET;
sin->sin_addr = fle->f.r.r_src;
rtalloc_ign(&ro, RTF_CLONING);
if (ro.ro_rt != NULL) {
struct rtentry *rt = ro.ro_rt;
if (rt_mask(rt))
fle->f.src_mask =
bit_count(((struct sockaddr_in *)rt_mask(rt))->sin_addr.s_addr);
else if (rt->rt_flags & RTF_HOST)
/* Give up. We can't determine mask :( */
fle->f.src_mask = 32;
RTFREE(ro.ro_rt);
}
/* Push new flow entry into flow cache */
mtx_lock(&priv->work_mtx);
LIST_INSERT_HEAD(&(h[slot].head), fle, fle_hash);
TAILQ_INSERT_TAIL(&priv->work_queue, fle, fle_work);
mtx_unlock(&priv->work_mtx);
return (0);
}
static __inline int
make_flow_rec(struct mbuf **m, int *plen, struct flow_rec *r,
uint8_t *tcp_flags, u_int16_t i_ifx)
{
register struct ip *ip;
int hlen;
int error = 0;
ip = mtod(*m, struct ip*);
/* check version */
if (ip->ip_v != IPVERSION)
return (EINVAL);
/* verify min header length */
hlen = ip->ip_hl << 2;
if (hlen < sizeof(struct ip))
return (EINVAL);
r->r_src = ip->ip_src;
r->r_dst = ip->ip_dst;
/* save packet length */
*plen = ntohs(ip->ip_len);
r->r_ip_p = ip->ip_p;
r->r_tos = ip->ip_tos;
/* Configured in_ifx overrides mbuf's */
if (i_ifx == 0) {
if ((*m)->m_pkthdr.rcvif)
r->r_i_ifx = (*m)->m_pkthdr.rcvif->if_index;
} else
r->r_i_ifx = i_ifx;
/*
* XXX NOTE: only first fragment of fragmented TCP, UDP and
* ICMP packet will be recorded with proper s_port and d_port.
* Following fragments will be recorded simply as IP packet with
* ip_proto = ip->ip_p and s_port, d_port set to zero.
* I know, it looks like bug. But I don't want to re-implement
* ip packet assebmling here. Anyway, (in)famous trafd works this way -
* and nobody complains yet :)
*/
if(ip->ip_off & htons(IP_OFFMASK))
return (0);
/* skip IP header */
m_adj(*m, hlen);
switch(r->r_ip_p) {
case IPPROTO_TCP:
{
register struct tcphdr *tcp;
/* verify that packet is not truncated */
if (CHECK_MLEN(*m, sizeof(struct tcphdr)))
ERROUT(EINVAL);
if (CHECK_PULLUP(*m, sizeof(struct tcphdr)))
ERROUT(ENOBUFS);
tcp = mtod(*m, struct tcphdr*);
r->r_sport = tcp->th_sport;
r->r_dport = tcp->th_dport;
*tcp_flags = tcp->th_flags;
break;
}
case IPPROTO_UDP:
/* verify that packet is not truncated */
if (CHECK_MLEN(*m, sizeof(struct udphdr)))
ERROUT(EINVAL);
if (CHECK_PULLUP(*m, sizeof(struct udphdr)))
ERROUT(ENOBUFS);
r->r_ports = *(mtod(*m, uint32_t *));
break;
}
done:
return (error);
}
/*
* Non-static functions called from ng_netflow.c
*/
/* Allocate memory and set up flow cache */
int
ng_netflow_cache_init(priv_p priv)
{
struct flow_entry *fle;
int i;
/* allocate cache */
MALLOC(priv->cache, struct flow_entry *,
CACHESIZE * sizeof(struct flow_entry),
M_NETFLOW, M_WAITOK | M_ZERO);
if (priv->cache == NULL)
return (ENOMEM);
/* allocate hash */
MALLOC(priv->hash, struct flow_hash_entry *,
NBUCKETS * sizeof(struct flow_hash_entry),
M_NETFLOW, M_WAITOK | M_ZERO);
if (priv->hash == NULL) {
FREE(priv->cache, M_NETFLOW);
return (ENOMEM);
}
TAILQ_INIT(&priv->work_queue);
SLIST_INIT(&priv->free_list);
SLIST_INIT(&priv->expire_list);
mtx_init(&priv->work_mtx, "ng_netflow cache mutex", NULL, MTX_DEF);
mtx_init(&priv->free_mtx, "ng_netflow free mutex", NULL, MTX_DEF);
mtx_init(&priv->expire_mtx, "ng_netflow expire mutex", NULL, MTX_DEF);
/* build free list */
for (i = 0, fle = priv->cache; i < CACHESIZE; i++, fle++)
SLIST_INSERT_HEAD(&priv->free_list, fle, fle_free);
priv->info.nfinfo_free = CACHESIZE;
return (0);
}
/* Free all flow cache memory. Called from node close method. */
void
ng_netflow_cache_flush(priv_p priv)
{
register struct flow_entry *fle;
int i;
/*
* We are going to free probably billable data.
* Expire everything before freeing it.
* No locking is required since callout is already drained.
*/
for (i = 0, fle = priv->cache; i < CACHESIZE; i++, fle++)
if (!ISFREE(fle))
/* ignore errors now */
(void )export_add(priv, fle);
mtx_destroy(&priv->work_mtx);
mtx_destroy(&priv->free_mtx);
mtx_destroy(&priv->expire_mtx);
/* free hash memory */
if (priv->hash)
FREE(priv->hash, M_NETFLOW);
/* free flow cache */
if (priv->cache)
FREE(priv->cache, M_NETFLOW);
}
/* Insert packet from &m into flow cache. */
int
ng_netflow_flow_add(priv_p priv, struct mbuf **m, iface_p iface)
{
struct flow_hash_entry *h = priv->hash;
register struct flow_entry *fle;
struct flow_rec r;
int plen;
int error = 0;
uint32_t slot;
uint8_t tcp_flags = 0;
/* Try to fill *rec */
bzero(&r, sizeof(r));
if ((error = make_flow_rec(m, &plen, &r, &tcp_flags,
iface->info.ifinfo_index)))
return (error);
slot = ip_hash(&r);
mtx_lock(&priv->work_mtx);
/* Update node statistics. */
priv->info.nfinfo_packets ++;
priv->info.nfinfo_bytes += plen;
fle = hash_lookup(h, slot, &r); /* New flow entry or existent? */
if (fle) { /* an existent entry */
TAILQ_REMOVE(&priv->work_queue, fle, fle_work);
fle->f.bytes += plen;
fle->f.packets ++;
fle->f.tcp_flags |= tcp_flags;
fle->f.last = time_uptime;
/*
* We have the following reasons to expire flow in active way:
* - it hit active timeout
* - a TCP connection closed
* - it is going to overflow counter
*/
if (tcp_flags & TH_FIN || tcp_flags & TH_RST || AGED(fle) ||
(fle->f.bytes >= (UINT_MAX - IF_MAXMTU)) )
expire_flow(priv, fle);
else
TAILQ_INSERT_TAIL(&priv->work_queue, fle, fle_work);
mtx_unlock(&priv->work_mtx);
} else { /* a new flow entry */
mtx_unlock(&priv->work_mtx);
return hash_insert(priv, slot, &r, plen);
}
mtx_assert(&priv->work_mtx, MA_NOTOWNED);
mtx_assert(&priv->expire_mtx, MA_NOTOWNED);
mtx_assert(&priv->free_mtx, MA_NOTOWNED);
return (0);
}
/*
* Return records from cache. netgraph(4) guarantees us that we
* are locked against ng_netflow_rcvdata(). However we can
* work with ng_netflow_expire() in parrallel. XXX: Is it dangerous?
*
* TODO: matching particular IP should be done in kernel, here.
*/
int
ng_netflow_flow_show(priv_p priv, uint32_t last, struct ng_mesg *resp)
{
struct flow_entry *fle;
struct ngnf_flows *data;
data = (struct ngnf_flows *)resp->data;
data->last = 0;
data->nentries = 0;
/* Check if this is a first run */
if (last == 0)
fle = priv->cache;
else {
if (last > CACHESIZE-1)
return (EINVAL);
fle = priv->cache + last;
}
/*
* We will transfer not more than NREC_AT_ONCE. More data
* will come in next message.
* We send current stop point to userland, and userland should return
* it back to us.
*/
for (; last < CACHESIZE; fle++, last++) {
if (ISFREE(fle))
continue;
bcopy(&fle->f, &(data->entries[data->nentries]),
sizeof(fle->f));
data->nentries ++;
if (data->nentries == NREC_AT_ONCE) {
if (++last < CACHESIZE)
data->last = (++fle - priv->cache);
return (0);
}
}
return (0);
}
/* We have full datagram in privdata. Send it to export hook. */
static int
export_send(priv_p priv)
{
struct netflow_v5_header *header = &priv->dgram.header;
struct timespec ts;
struct mbuf *m;
int error = 0;
int mlen;
header->sys_uptime = htonl(time_uptime);
getnanotime(&ts);
header->unix_secs = htonl(ts.tv_sec);
header->unix_nsecs = htonl(ts.tv_nsec);
/* Flow sequence contains number of first record */
header->flow_seq = htonl(priv->flow_seq - header->count);
mlen = sizeof(struct netflow_v5_header) +
sizeof(struct netflow_v5_record) * header->count;
header->count = htons(header->count);
if ((m = m_devget((caddr_t)header, mlen, 0, NULL, NULL)) == NULL) {
log(LOG_CRIT, "ng_netflow: m_devget() failed, losing export "
"dgram\n");
header->count = 0;
return(ENOBUFS);
}
header->count = 0;
/* Giant is required in sosend() at this moment. */
NET_LOCK_GIANT();
NG_SEND_DATA_ONLY(error, priv->export, m);
NET_UNLOCK_GIANT();
if (error)
NG_FREE_M(m);
return (error);
}
/* Create export datagram. */
static int
export_add(priv_p priv, struct flow_entry *fle)
{
struct netflow_v5_header *header = &priv->dgram.header;
struct netflow_v5_record *rec;
if (header->count == 0 ) { /* first record */
rec = &priv->dgram.r[0];
header->count = 1;
} else { /* continue filling datagram */
rec = &priv->dgram.r[header->count];
header->count ++;
}
/* Fill in export record */
rec->src_addr = fle->f.r.r_src.s_addr;
rec->dst_addr = fle->f.r.r_dst.s_addr;
rec->next_hop = fle->f.next_hop.s_addr;
rec->i_ifx = htons(fle->f.fle_i_ifx);
rec->o_ifx = htons(fle->f.fle_o_ifx);
rec->packets = htonl(fle->f.packets);
rec->octets = htonl(fle->f.bytes);
rec->first = htonl(fle->f.first);
rec->last = htonl(fle->f.last);
rec->s_port = fle->f.r.r_sport;
rec->d_port = fle->f.r.r_dport;
rec->flags = fle->f.tcp_flags;
rec->prot = fle->f.r.r_ip_p;
rec->tos = fle->f.r.r_tos;
rec->dst_mask = fle->f.dst_mask;
rec->src_mask = fle->f.src_mask;
priv->flow_seq++;
if (header->count == NETFLOW_V5_MAX_RECORDS) /* end of datagram */
return export_send(priv);
return (0);
}
/* Periodic flow expiry run. */
void
ng_netflow_expire(void *arg)
{
register struct flow_entry *fle, *fle1;
priv_p priv = (priv_p )arg;
uint32_t used;
int error = 0;
/* First pack actively expired entries */
mtx_lock(&priv->expire_mtx);
while (!SLIST_EMPTY(&(priv->expire_list))) {
fle = SLIST_FIRST(&(priv->expire_list));
SLIST_REMOVE_HEAD(&(priv->expire_list), fle_free);
mtx_unlock(&priv->expire_mtx);
/*
* While we have dropped the lock, expire_flow() may
* insert another flow into top of the list.
* This is not harmful for us, since we have already
* detached our own.
*/
if ((error = export_add(priv, fle)) != 0)
log(LOG_CRIT, "ng_netflow: export_add() failed: %u\n",
error);
(void )free_flow(priv, fle);
mtx_lock(&priv->expire_mtx);
}
mtx_unlock(&priv->expire_mtx);
NGNF_GETUSED(priv, used);
mtx_lock(&priv->work_mtx);
TAILQ_FOREACH_SAFE(fle, &(priv->work_queue), fle_work, fle1) {
/*
* When cache size has not reached CACHELOWAT yet, we keep
* both inactive and active flows in cache. Doing this, we
* reduce number of exports, since many inactive flows may
* wake up and continue their life. However, we make an
* exclusion for scans. It is very rare situation that
* inactive 1-packet flow will wake up.
* When cache has reached CACHELOWAT, we expire all inactive
* flows, until cache gets to a sane size.
*/
if (used <= CACHELOWAT && !INACTIVE(fle))
goto finish;
if ((INACTIVE(fle) && (SMALL(fle) || (used > CACHELOWAT))) ||
AGED(fle)) {
/* Detach flow entry from cache */
LIST_REMOVE(fle, fle_hash);
TAILQ_REMOVE(&priv->work_queue, fle, fle_work);
/*
* While we are sending to collector, unlock cache.
* XXX: it can happen, however with a small probability,
* that item, we are holding now, can be moved to the
* top of flow cache by node thread. In this case our
* expire thread stops checking. Since this is not
* fatal we will just ignore it now.
*/
mtx_unlock(&priv->work_mtx);
if ((error = export_add(priv, fle)) != 0)
log(LOG_CRIT, "ng_netflow: export_add() "
"failed: %u\n", error);
used = free_flow(priv, fle);
mtx_lock(&priv->work_mtx);
}
}
finish:
mtx_unlock(&priv->work_mtx);
mtx_assert(&priv->expire_mtx, MA_NOTOWNED);
mtx_assert(&priv->free_mtx, MA_NOTOWNED);
/* schedule next expire */
callout_reset(&priv->exp_callout, (1*hz), &ng_netflow_expire,
(void *)priv);
}