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Modify the IP fragment reassembly code so that it uses a new UMA zone,

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ipq_zone, to allocate fragment headers from, rather than using cast mbuf
storage.  This was one of the few remaining uses of mbuf storage for
local data structures that relied on dtom().  Implement the resource
limit on ipq's using UMA zone limits, but preserve current sysctl
semantics using a sysctl proc.

MFC after:	3 weeks
This commit is contained in:
rwatson 2006-01-15 18:58:21 +00:00
parent 602aa13ac2
commit ea56477c5e
1 changed files with 81 additions and 21 deletions
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102
sys/netinet/ip_input.c
View File

@ -107,17 +107,6 @@ SYSCTL_INT(_net_inet_ip, IPCTL_KEEPFAITH, keepfaith, CTLFLAG_RW,
&ip_keepfaith, 0,
"Enable packet capture for FAITH IPv4->IPv6 translater daemon");
static int nipq = 0; /* total # of reass queues */
static int maxnipq;
SYSCTL_INT(_net_inet_ip, OID_AUTO, maxfragpackets, CTLFLAG_RW,
&maxnipq, 0,
"Maximum number of IPv4 fragment reassembly queue entries");
static int maxfragsperpacket;
SYSCTL_INT(_net_inet_ip, OID_AUTO, maxfragsperpacket, CTLFLAG_RW,
&maxfragsperpacket, 0,
"Maximum number of IPv4 fragments allowed per packet");
static int ip_sendsourcequench = 0;
SYSCTL_INT(_net_inet_ip, OID_AUTO, sendsourcequench, CTLFLAG_RW,
&ip_sendsourcequench, 0,
@ -166,22 +155,38 @@ struct ipstat ipstat;
SYSCTL_STRUCT(_net_inet_ip, IPCTL_STATS, stats, CTLFLAG_RW,
&ipstat, ipstat, "IP statistics (struct ipstat, netinet/ip_var.h)");
/* Packet reassembly stuff */
/*
* IP datagram reassembly.
*/
#define IPREASS_NHASH_LOG2 6
#define IPREASS_NHASH (1 << IPREASS_NHASH_LOG2)
#define IPREASS_HMASK (IPREASS_NHASH - 1)
#define IPREASS_HASH(x,y) \
(((((x) & 0xF) | ((((x) >> 8) & 0xF) << 4)) ^ (y)) & IPREASS_HMASK)
static uma_zone_t ipq_zone;
static TAILQ_HEAD(ipqhead, ipq) ipq[IPREASS_NHASH];
static struct mtx ipqlock;
struct callout ipport_tick_callout;
#define IPQ_LOCK() mtx_lock(&ipqlock)
#define IPQ_UNLOCK() mtx_unlock(&ipqlock)
#define IPQ_LOCK_INIT() mtx_init(&ipqlock, "ipqlock", NULL, MTX_DEF)
#define IPQ_LOCK_ASSERT() mtx_assert(&ipqlock, MA_OWNED)
static void maxnipq_update(void);
static int maxnipq; /* Administrative limit on # reass queues. */
static int nipq = 0; /* Total # of reass queues */
SYSCTL_INT(_net_inet_ip, OID_AUTO, fragpackets, CTLFLAG_RD, &nipq, 0,
"Current number of IPv4 fragment reassembly queue entries");
static int maxfragsperpacket;
SYSCTL_INT(_net_inet_ip, OID_AUTO, maxfragsperpacket, CTLFLAG_RW,
&maxfragsperpacket, 0,
"Maximum number of IPv4 fragments allowed per packet");
struct callout ipport_tick_callout;
#ifdef IPCTL_DEFMTU
SYSCTL_INT(_net_inet_ip, IPCTL_DEFMTU, mtu, CTLFLAG_RW,
&ip_mtu, 0, "Default MTU");
@ -249,6 +254,9 @@ ip_init()
TAILQ_INIT(&ipq[i]);
maxnipq = nmbclusters / 32;
maxfragsperpacket = 16;
ipq_zone = uma_zcreate("ipq", sizeof(struct ipq), NULL, NULL, NULL,
NULL, UMA_ALIGN_PTR, 0);
maxnipq_update();
/* Start ipport_tick. */
callout_init(&ipport_tick_callout, CALLOUT_MPSAFE);
@ -746,6 +754,59 @@ DPRINTF(("ip_input: no SP, packet discarded\n"));/*XXX*/
m_freem(m);
}
/*
* After maxnipq has been updated, propagate the change to UMA. The UMA zone
* max has slightly different semantics than the sysctl, for historical
* reasons.
*/
static void
maxnipq_update(void)
{
/*
* -1 for unlimited allocation.
*/
if (maxnipq < 0)
uma_zone_set_max(ipq_zone, 0);
/*
* Positive number for specific bound.
*/
if (maxnipq > 0)
uma_zone_set_max(ipq_zone, maxnipq);
/*
* Zero specifies no further fragment queue allocation -- set the
* bound very low, but rely on implementation elsewhere to actually
* prevent allocation and reclaim current queues.
*/
if (maxnipq == 0)
uma_zone_set_max(ipq_zone, 1);
}
static int
sysctl_maxnipq(SYSCTL_HANDLER_ARGS)
{
int error, i;
i = maxnipq;
error = sysctl_handle_int(oidp, &i, 0, req);
if (error || !req->newptr)
return (error);
/*
* XXXRW: Might be a good idea to sanity check the argument and place
* an extreme upper bound.
*/
if (i < -1)
return (EINVAL);
maxnipq = i;
maxnipq_update();
return (0);
}
SYSCTL_PROC(_net_inet_ip, OID_AUTO, maxfragpackets, CTLTYPE_INT|CTLFLAG_RW,
NULL, 0, sysctl_maxnipq, "I",
"Maximum number of IPv4 fragment reassembly queue entries");
/*
* Take incoming datagram fragment and try to reassemble it into
* whole datagram. If the argument is the first fragment or one
@ -800,9 +861,8 @@ ip_reass(struct mbuf *m)
fp = NULL;
/*
* Enforce upper bound on number of fragmented packets
* for which we attempt reassembly;
* If maxnipq is -1, accept all fragments without limitation.
* Attempt to trim the number of allocated fragment queues if it
* exceeds the administrative limit.
*/
if ((nipq > maxnipq) && (maxnipq > 0)) {
/*
@ -865,12 +925,12 @@ ip_reass(struct mbuf *m)
* If first fragment to arrive, create a reassembly queue.
*/
if (fp == NULL) {
if ((t = m_get(M_DONTWAIT, MT_FTABLE)) == NULL)
fp = uma_zalloc(ipq_zone, M_NOWAIT);
if (fp == NULL)
goto dropfrag;
fp = mtod(t, struct ipq *);
#ifdef MAC
if (mac_init_ipq(fp, M_NOWAIT) != 0) {
m_free(t);
uma_zfree(ipq_zone, fp);
goto dropfrag;
}
mac_create_ipq(m, fp);
@ -1038,7 +1098,7 @@ ip_reass(struct mbuf *m)
ip->ip_dst = fp->ipq_dst;
TAILQ_REMOVE(head, fp, ipq_list);
nipq--;
(void) m_free(dtom(fp));
uma_zfree(ipq_zone, fp);
m->m_len += (ip->ip_hl << 2);
m->m_data -= (ip->ip_hl << 2);
/* some debugging cruft by sklower, below, will go away soon */
@ -1079,7 +1139,7 @@ ip_freef(fhp, fp)
m_freem(q);
}
TAILQ_REMOVE(fhp, fp, ipq_list);
(void) m_free(dtom(fp));
uma_zfree(ipq_zone, fp);
nipq--;
}