freebsd-dev/sys/netgraph/netflow/netflow.c
Gleb Smirnoff 73189791f2 When sending export datagram from interrupt thread, use NG_QUEUE
in flags. When sending export datagram from expiry thread, then
use default zero flags. This removes unpleasant contention of the
interrupt thread on mutexes (usually ng_ksocket's socket buffer
mutex).
2006-01-12 22:48:12 +00:00

738 lines
19 KiB
C

/*-
* Copyright (c) 2004-2005 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 <machine/atomic.h>
#include <net/if.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 (65536) /* 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 is 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)
/*
* Cisco uses milliseconds for uptime. Bad idea, since it overflows
* every 48+ days. But we will do same to keep compatibility. This macro
* does overflowable multiplication to 1000.
*/
#define MILLIUPTIME(t) (((t) << 9) + /* 512 */ \
((t) << 8) + /* 256 */ \
((t) << 7) + /* 128 */ \
((t) << 6) + /* 64 */ \
((t) << 5) + /* 32 */ \
((t) << 3)) /* 8 */
MALLOC_DECLARE(M_NETFLOW_HASH);
MALLOC_DEFINE(M_NETFLOW_HASH, "netflow_hash", "NetFlow hash");
static int export_add(item_p, struct flow_entry *);
static int export_send(priv_p, item_p, int flags);
/* 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);
}
}
/* This is callback from uma(9), called on alloc. */
static int
uma_ctor_flow(void *mem, int size, void *arg, int how)
{
priv_p priv = (priv_p )arg;
if (atomic_load_acq_32(&priv->info.nfinfo_used) >= CACHESIZE)
return (ENOMEM);
atomic_add_32(&priv->info.nfinfo_used, 1);
return (0);
}
/* This is callback from uma(9), called on free. */
static void
uma_dtor_flow(void *mem, int size, void *arg)
{
priv_p priv = (priv_p )arg;
atomic_subtract_32(&priv->info.nfinfo_used, 1);
}
/*
* Detach export datagram from priv, if there is any.
* If there is no, allocate a new one.
*/
static item_p
get_export_dgram(priv_p priv)
{
item_p item = NULL;
mtx_lock(&priv->export_mtx);
if (priv->export_item != NULL) {
item = priv->export_item;
priv->export_item = NULL;
}
mtx_unlock(&priv->export_mtx);
if (item == NULL) {
struct netflow_v5_export_dgram *dgram;
struct mbuf *m;
m = m_getcl(M_DONTWAIT, MT_DATA, M_PKTHDR);
if (m == NULL)
return (NULL);
item = ng_package_data(m, NG_NOFLAGS);
if (item == NULL)
return (NULL);
dgram = mtod(m, struct netflow_v5_export_dgram *);
dgram->header.count = 0;
dgram->header.version = htons(NETFLOW_V5);
}
return (item);
}
/*
* Re-attach incomplete datagram back to priv.
* If there is already another one, then send incomplete. */
static void
return_export_dgram(priv_p priv, item_p item, int flags)
{
/*
* It may happen on SMP, that some thread has already
* put its item there, in this case we bail out and
* send what we have to collector.
*/
mtx_lock(&priv->export_mtx);
if (priv->export_item == NULL) {
priv->export_item = item;
mtx_unlock(&priv->export_mtx);
} else {
mtx_unlock(&priv->export_mtx);
export_send(priv, item, flags);
}
}
/*
* The flow is over. Call export_add() and free it. If datagram is
* full, then call export_send().
*/
static __inline void
expire_flow(priv_p priv, item_p *item, struct flow_entry *fle, int flags)
{
if (*item == NULL)
*item = get_export_dgram(priv);
if (*item == NULL) {
atomic_add_32(&priv->info.nfinfo_export_failed, 1);
uma_zfree_arg(priv->zone, fle, priv);
return;
}
if (export_add(*item, fle) > 0) {
export_send(priv, *item, flags);
*item = NULL;
}
uma_zfree_arg(priv->zone, fle, priv);
}
/* Get a snapshot of node statistics */
void
ng_netflow_copyinfo(priv_p priv, struct ng_netflow_info *i)
{
/* XXX: atomic */
memcpy((void *)i, (void *)&priv->info, sizeof(priv->info));
}
/* 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.
*
* TODO: consider dropping hash mutex while filling in datagram,
* as this was done in previous version. Need to test & profile
* to be sure.
*/
static __inline int
hash_insert(priv_p priv, struct flow_hash_entry *hsh, struct flow_rec *r,
int plen, uint8_t tcp_flags)
{
struct flow_entry *fle;
struct route ro;
struct sockaddr_in *sin;
mtx_assert(&hsh->mtx, MA_OWNED);
fle = uma_zalloc_arg(priv->zone, priv, M_NOWAIT);
if (fle == NULL) {
atomic_add_32(&priv->info.nfinfo_alloc_failed, 1);
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;
fle->f.tcp_flags = tcp_flags;
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 at the and of hash. */
TAILQ_INSERT_TAIL(&hsh->head, fle, fle_hash);
return (0);
}
/*
* 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_hash_entry *hsh;
int i;
/* Initialize cache UMA zone. */
priv->zone = uma_zcreate("NetFlow cache", sizeof(struct flow_entry),
uma_ctor_flow, uma_dtor_flow, NULL, NULL, UMA_ALIGN_CACHE, 0);
uma_zone_set_max(priv->zone, CACHESIZE);
/* Allocate hash. */
MALLOC(priv->hash, struct flow_hash_entry *,
NBUCKETS * sizeof(struct flow_hash_entry),
M_NETFLOW_HASH, M_WAITOK | M_ZERO);
if (priv->hash == NULL) {
uma_zdestroy(priv->zone);
return (ENOMEM);
}
/* Initialize hash. */
for (i = 0, hsh = priv->hash; i < NBUCKETS; i++, hsh++) {
mtx_init(&hsh->mtx, "hash mutex", NULL, MTX_DEF);
TAILQ_INIT(&hsh->head);
}
mtx_init(&priv->export_mtx, "export dgram lock", NULL, MTX_DEF);
return (0);
}
/* Free all flow cache memory. Called from node close method. */
void
ng_netflow_cache_flush(priv_p priv)
{
struct flow_entry *fle, *fle1;
struct flow_hash_entry *hsh;
item_p item = NULL;
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 (hsh = priv->hash, i = 0; i < NBUCKETS; hsh++, i++)
TAILQ_FOREACH_SAFE(fle, &hsh->head, fle_hash, fle1) {
TAILQ_REMOVE(&hsh->head, fle, fle_hash);
expire_flow(priv, &item, fle, NG_QUEUE);
}
if (item != NULL)
export_send(priv, item, NG_QUEUE);
uma_zdestroy(priv->zone);
/* Destroy hash mutexes. */
for (i = 0, hsh = priv->hash; i < NBUCKETS; i++, hsh++)
mtx_destroy(&hsh->mtx);
/* Free hash memory. */
if (priv->hash)
FREE(priv->hash, M_NETFLOW_HASH);
mtx_destroy(&priv->export_mtx);
}
/* Insert packet from into flow cache. */
int
ng_netflow_flow_add(priv_p priv, struct ip *ip, iface_p iface,
struct ifnet *ifp)
{
register struct flow_entry *fle, *fle1;
struct flow_hash_entry *hsh;
struct flow_rec r;
item_p item = NULL;
int hlen, plen;
int error = 0;
uint8_t tcp_flags = 0;
/* Try to fill flow_rec r */
bzero(&r, sizeof(r));
/* 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 (iface->info.ifinfo_index == 0) {
if (ifp != NULL)
r.r_i_ifx = ifp->if_index;
} else
r.r_i_ifx = iface->info.ifinfo_index;
/*
* 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)) == 0)
switch(r.r_ip_p) {
case IPPROTO_TCP:
{
register struct tcphdr *tcp;
tcp = (struct tcphdr *)((caddr_t )ip + hlen);
r.r_sport = tcp->th_sport;
r.r_dport = tcp->th_dport;
tcp_flags = tcp->th_flags;
break;
}
case IPPROTO_UDP:
r.r_ports = *(uint32_t *)((caddr_t )ip + hlen);
break;
}
/* Update node statistics. XXX: race... */
priv->info.nfinfo_packets ++;
priv->info.nfinfo_bytes += plen;
/* Find hash slot. */
hsh = &priv->hash[ip_hash(&r)];
mtx_lock(&hsh->mtx);
/*
* Go through hash and find our entry. If we encounter an
* entry, that should be expired, purge it. We do a reverse
* search since most active entries are first, and most
* searches are done on most active entries.
*/
TAILQ_FOREACH_REVERSE_SAFE(fle, &hsh->head, fhead, fle_hash, fle1) {
if (bcmp(&r, &fle->f.r, sizeof(struct flow_rec)) == 0)
break;
if ((INACTIVE(fle) && SMALL(fle)) || AGED(fle)) {
TAILQ_REMOVE(&hsh->head, fle, fle_hash);
expire_flow(priv, &item, fle, NG_QUEUE);
atomic_add_32(&priv->info.nfinfo_act_exp, 1);
}
}
if (fle) { /* An existent entry. */
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)) ) {
TAILQ_REMOVE(&hsh->head, fle, fle_hash);
expire_flow(priv, &item, fle, NG_QUEUE);
atomic_add_32(&priv->info.nfinfo_act_exp, 1);
} else {
/*
* It is the newest, move it to the tail,
* if it isn't there already. Next search will
* locate it quicker.
*/
if (fle != TAILQ_LAST(&hsh->head, fhead)) {
TAILQ_REMOVE(&hsh->head, fle, fle_hash);
TAILQ_INSERT_TAIL(&hsh->head, fle, fle_hash);
}
}
} else /* A new flow entry. */
error = hash_insert(priv, hsh, &r, plen, tcp_flags);
mtx_unlock(&hsh->mtx);
if (item != NULL)
return_export_dgram(priv, item, NG_QUEUE);
return (error);
}
/*
* Return records from cache to userland.
*
* 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_hash_entry *hsh;
struct flow_entry *fle;
struct ngnf_flows *data;
int i;
data = (struct ngnf_flows *)resp->data;
data->last = 0;
data->nentries = 0;
/* Check if this is a first run */
if (last == 0) {
hsh = priv->hash;
i = 0;
} else {
if (last > NBUCKETS-1)
return (EINVAL);
hsh = priv->hash + last;
i = last;
}
/*
* We will transfer not more than NREC_AT_ONCE. More data
* will come in next message.
* We send current hash index to userland, and userland should
* return it back to us. Then, we will restart with new entry.
*
* The resulting cache snapshot is inaccurate for the
* following reasons:
* - we skip locked hash entries
* - we bail out, if someone wants our entry
* - we skip rest of entry, when hit NREC_AT_ONCE
*/
for (; i < NBUCKETS; hsh++, i++) {
if (mtx_trylock(&hsh->mtx) == 0)
continue;
TAILQ_FOREACH(fle, &hsh->head, fle_hash) {
if (hsh->mtx.mtx_lock & MTX_CONTESTED)
break;
bcopy(&fle->f, &(data->entries[data->nentries]),
sizeof(fle->f));
data->nentries++;
if (data->nentries == NREC_AT_ONCE) {
mtx_unlock(&hsh->mtx);
if (++i < NBUCKETS)
data->last = i;
return (0);
}
}
mtx_unlock(&hsh->mtx);
}
return (0);
}
/* We have full datagram in privdata. Send it to export hook. */
static int
export_send(priv_p priv, item_p item, int flags)
{
struct mbuf *m = NGI_M(item);
struct netflow_v5_export_dgram *dgram = mtod(m,
struct netflow_v5_export_dgram *);
struct netflow_v5_header *header = &dgram->header;
struct timespec ts;
int error = 0;
/* Fill mbuf header. */
m->m_len = m->m_pkthdr.len = sizeof(struct netflow_v5_record) *
header->count + sizeof(struct netflow_v5_header);
/* Fill export header. */
header->sys_uptime = htonl(MILLIUPTIME(time_uptime));
getnanotime(&ts);
header->unix_secs = htonl(ts.tv_sec);
header->unix_nsecs = htonl(ts.tv_nsec);
header->flow_seq = htonl(atomic_fetchadd_32(&priv->flow_seq,
header->count));
header->count = htons(header->count);
if (priv->export != NULL)
/* Should also NET_LOCK_GIANT(). */
NG_FWD_ITEM_HOOK_FLAGS(error, item, priv->export, flags);
return (error);
}
/* Add export record to dgram. */
static int
export_add(item_p item, struct flow_entry *fle)
{
struct netflow_v5_export_dgram *dgram = mtod(NGI_M(item),
struct netflow_v5_export_dgram *);
struct netflow_v5_header *header = &dgram->header;
struct netflow_v5_record *rec;
if (header->count == 0 ) { /* first record */
rec = &dgram->r[0];
header->count = 1;
} else { /* continue filling datagram */
rec = &dgram->r[header->count];
header->count ++;
}
KASSERT(header->count <= NETFLOW_V5_MAX_RECORDS,
("ng_netflow: export too big"));
/* 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(MILLIUPTIME(fle->f.first));
rec->last = htonl(MILLIUPTIME(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;
/* Not supported fields. */
rec->src_as = rec->dst_as = 0;
if (header->count == NETFLOW_V5_MAX_RECORDS)
return (1); /* end of datagram */
else
return (0);
}
/* Periodic flow expiry run. */
void
ng_netflow_expire(void *arg)
{
struct flow_entry *fle, *fle1;
struct flow_hash_entry *hsh;
priv_p priv = (priv_p )arg;
item_p item = NULL;
uint32_t used;
int i;
/*
* Going through all the cache.
*/
for (hsh = priv->hash, i = 0; i < NBUCKETS; hsh++, i++) {
/*
* Skip entries, that are already being worked on.
*/
if (mtx_trylock(&hsh->mtx) == 0)
continue;
used = atomic_load_acq_32(&priv->info.nfinfo_used);
TAILQ_FOREACH_SAFE(fle, &hsh->head, fle_hash, fle1) {
/*
* Interrupt thread wants this entry!
* Quick! Quick! Bail out!
*/
if (hsh->mtx.mtx_lock & MTX_CONTESTED)
break;
/*
* Don't expire aggressively while hash collision
* ratio is predicted small.
*/
if (used <= (NBUCKETS*2) && !INACTIVE(fle))
break;
if ((INACTIVE(fle) && (SMALL(fle) || (used > (NBUCKETS*2)))) ||
AGED(fle)) {
TAILQ_REMOVE(&hsh->head, fle, fle_hash);
expire_flow(priv, &item, fle, NG_NOFLAGS);
used--;
atomic_add_32(&priv->info.nfinfo_inact_exp, 1);
}
}
mtx_unlock(&hsh->mtx);
}
if (item != NULL)
return_export_dgram(priv, item, NG_NOFLAGS);
/* Schedule next expire. */
callout_reset(&priv->exp_callout, (1*hz), &ng_netflow_expire,
(void *)priv);
}