Userspace utilities commonly transform a prefix length (CIDR notation
like 192.168.222.1/32) into a full netmask before submitting it to
the kernel.
The size of struct xt_conntrack_mtinfo1 is currently 152 bytes, of
which 64 bytes are for masks. By submitting prefix lengths to the
kernel instead, 60 bytes (almost 40%) memory per rule can be saved as
prefix lengths can fit into one uint8_t. Since we do not want to
recompute the mask for each invocation of the match function, a
static translation table will be used (net/core/pfxlen.c).
The patch changes xt_conntrack revision 1 into revision 2.
Userspace can easily fall back to revision 0.
The patch also removes xt_hashlimit's obsolete mask computation.
Signed-off-by: Jan Engelhardt <jengelh@xxxxxxxxxxxxxxx>
---
include/linux/netfilter/xt_conntrack.h | 12 +-
include/net/pfxlen.h | 8 ++
net/Kconfig | 6 +
net/core/Makefile | 1 +
net/core/pfxlen.c | 146 ++++++++++++++++++++++++
net/netfilter/Kconfig | 1 +
net/netfilter/xt_conntrack.c | 43 +++++---
net/netfilter/xt_hashlimit.c | 40 ++-----
8 files changed, 206 insertions(+), 51 deletions(-)
create mode 100644 include/net/pfxlen.h
create mode 100644 net/core/pfxlen.c
diff --git a/include/linux/netfilter/xt_conntrack.h b/include/linux/netfilter/xt_conntrack.h
index f3fd83e..79540e6 100644
--- a/include/linux/netfilter/xt_conntrack.h
+++ b/include/linux/netfilter/xt_conntrack.h
@@ -67,17 +67,19 @@ struct xt_conntrack_info
u_int8_t invflags;
};
-struct xt_conntrack_mtinfo1 {
- union nf_inet_addr origsrc_addr, origsrc_mask;
- union nf_inet_addr origdst_addr, origdst_mask;
- union nf_inet_addr replsrc_addr, replsrc_mask;
- union nf_inet_addr repldst_addr, repldst_mask;
+struct xt_conntrack_mtinfo2 {
+ union nf_inet_addr origsrc_addr;
+ union nf_inet_addr origdst_addr;
+ union nf_inet_addr replsrc_addr;
+ union nf_inet_addr repldst_addr;
u_int32_t expires_min, expires_max;
u_int16_t l4proto;
__be16 origsrc_port, origdst_port;
__be16 replsrc_port, repldst_port;
u_int16_t match_flags, invert_flags;
u_int8_t state_mask, status_mask;
+ u_int8_t origsrc_pfx, origdst_pfx;
+ u_int8_t replsrc_pfx, repldst_pfx;
};
#endif /*_XT_CONNTRACK_H*/
diff --git a/include/net/pfxlen.h b/include/net/pfxlen.h
new file mode 100644
index 0000000..203a494
--- /dev/null
+++ b/include/net/pfxlen.h
@@ -0,0 +1,8 @@
+#ifndef _NET_PFXLEN_H
+#define _NET_PFXLEN_H 1
+
+#include <linux/netfilter.h>
+
+extern union nf_inet_addr prefixlen_netmask_map[];
+
+#endif /* _NET_PFXLEN_H */
diff --git a/net/Kconfig b/net/Kconfig
index acbf7c6..c355f08 100644
--- a/net/Kconfig
+++ b/net/Kconfig
@@ -27,6 +27,12 @@ if NET
menu "Networking options"
+config NET_PFXLEN
+ tristate
+ ---help---
+ This option adds a translation table from prefix length to
+ expanded netmasks (e.g. /28 => 255.255.255.240)
+
config NET_NS
bool "Network namespace support"
default n
diff --git a/net/core/Makefile b/net/core/Makefile
index b1332f6..cc818dd 100644
--- a/net/core/Makefile
+++ b/net/core/Makefile
@@ -16,3 +16,4 @@ obj-$(CONFIG_NET_PKTGEN) += pktgen.o
obj-$(CONFIG_NETPOLL) += netpoll.o
obj-$(CONFIG_NET_DMA) += user_dma.o
obj-$(CONFIG_FIB_RULES) += fib_rules.o
+obj-$(CONFIG_NET_PFXLEN) += pfxlen.o
diff --git a/net/core/pfxlen.c b/net/core/pfxlen.c
new file mode 100644
index 0000000..5667c03
--- /dev/null
+++ b/net/core/pfxlen.c
@@ -0,0 +1,146 @@
+#include <linux/netfilter.h>
+
+#define E(a, b, c, d) \
+ {.ip6 = { \
+ __constant_htonl(a), __constant_htonl(b), \
+ __constant_htonl(c), __constant_htonl(d), \
+ }}
+
+/*
+ * This table works for both IPv4 and IPv6;
+ * just use prefixlen_netmask_map[prefixlength].ip.
+ */
+const union nf_inet_addr prefixlen_netmask_map[] = {
+ E(0x00000000, 0x00000000, 0x00000000, 0x00000000),
+ E(0x80000000, 0x00000000, 0x00000000, 0x00000000),
+ E(0xC0000000, 0x00000000, 0x00000000, 0x00000000),
+ E(0xE0000000, 0x00000000, 0x00000000, 0x00000000),
+ E(0xF0000000, 0x00000000, 0x00000000, 0x00000000),
+ E(0xF8000000, 0x00000000, 0x00000000, 0x00000000),
+ E(0xFC000000, 0x00000000, 0x00000000, 0x00000000),
+ E(0xFE000000, 0x00000000, 0x00000000, 0x00000000),
+ E(0xFF000000, 0x00000000, 0x00000000, 0x00000000),
+ E(0xFF800000, 0x00000000, 0x00000000, 0x00000000),
+ E(0xFFC00000, 0x00000000, 0x00000000, 0x00000000),
+ E(0xFFE00000, 0x00000000, 0x00000000, 0x00000000),
+ E(0xFFF00000, 0x00000000, 0x00000000, 0x00000000),
+ E(0xFFF80000, 0x00000000, 0x00000000, 0x00000000),
+ E(0xFFFC0000, 0x00000000, 0x00000000, 0x00000000),
+ E(0xFFFE0000, 0x00000000, 0x00000000, 0x00000000),
+ E(0xFFFF0000, 0x00000000, 0x00000000, 0x00000000),
+ E(0xFFFF8000, 0x00000000, 0x00000000, 0x00000000),
+ E(0xFFFFC000, 0x00000000, 0x00000000, 0x00000000),
+ E(0xFFFFE000, 0x00000000, 0x00000000, 0x00000000),
+ E(0xFFFFF000, 0x00000000, 0x00000000, 0x00000000),
+ E(0xFFFFF800, 0x00000000, 0x00000000, 0x00000000),
+ E(0xFFFFFC00, 0x00000000, 0x00000000, 0x00000000),
+ E(0xFFFFFE00, 0x00000000, 0x00000000, 0x00000000),
+ E(0xFFFFFF00, 0x00000000, 0x00000000, 0x00000000),
+ E(0xFFFFFF80, 0x00000000, 0x00000000, 0x00000000),
+ E(0xFFFFFFC0, 0x00000000, 0x00000000, 0x00000000),
+ E(0xFFFFFFE0, 0x00000000, 0x00000000, 0x00000000),
+ E(0xFFFFFFF0, 0x00000000, 0x00000000, 0x00000000),
+ E(0xFFFFFFF8, 0x00000000, 0x00000000, 0x00000000),
+ E(0xFFFFFFFC, 0x00000000, 0x00000000, 0x00000000),
+ E(0xFFFFFFFE, 0x00000000, 0x00000000, 0x00000000),
+ E(0xFFFFFFFF, 0x00000000, 0x00000000, 0x00000000),
+ E(0xFFFFFFFF, 0x80000000, 0x00000000, 0x00000000),
+ E(0xFFFFFFFF, 0xC0000000, 0x00000000, 0x00000000),
+ E(0xFFFFFFFF, 0xE0000000, 0x00000000, 0x00000000),
+ E(0xFFFFFFFF, 0xF0000000, 0x00000000, 0x00000000),
+ E(0xFFFFFFFF, 0xF8000000, 0x00000000, 0x00000000),
+ E(0xFFFFFFFF, 0xFC000000, 0x00000000, 0x00000000),
+ E(0xFFFFFFFF, 0xFE000000, 0x00000000, 0x00000000),
+ E(0xFFFFFFFF, 0xFF000000, 0x00000000, 0x00000000),
+ E(0xFFFFFFFF, 0xFF800000, 0x00000000, 0x00000000),
+ E(0xFFFFFFFF, 0xFFC00000, 0x00000000, 0x00000000),
+ E(0xFFFFFFFF, 0xFFE00000, 0x00000000, 0x00000000),
+ E(0xFFFFFFFF, 0xFFF00000, 0x00000000, 0x00000000),
+ E(0xFFFFFFFF, 0xFFF80000, 0x00000000, 0x00000000),
+ E(0xFFFFFFFF, 0xFFFC0000, 0x00000000, 0x00000000),
+ E(0xFFFFFFFF, 0xFFFE0000, 0x00000000, 0x00000000),
+ E(0xFFFFFFFF, 0xFFFF0000, 0x00000000, 0x00000000),
+ E(0xFFFFFFFF, 0xFFFF8000, 0x00000000, 0x00000000),
+ E(0xFFFFFFFF, 0xFFFFC000, 0x00000000, 0x00000000),
+ E(0xFFFFFFFF, 0xFFFFE000, 0x00000000, 0x00000000),
+ E(0xFFFFFFFF, 0xFFFFF000, 0x00000000, 0x00000000),
+ E(0xFFFFFFFF, 0xFFFFF800, 0x00000000, 0x00000000),
+ E(0xFFFFFFFF, 0xFFFFFC00, 0x00000000, 0x00000000),
+ E(0xFFFFFFFF, 0xFFFFFE00, 0x00000000, 0x00000000),
+ E(0xFFFFFFFF, 0xFFFFFF00, 0x00000000, 0x00000000),
+ E(0xFFFFFFFF, 0xFFFFFF80, 0x00000000, 0x00000000),
+ E(0xFFFFFFFF, 0xFFFFFFC0, 0x00000000, 0x00000000),
+ E(0xFFFFFFFF, 0xFFFFFFE0, 0x00000000, 0x00000000),
+ E(0xFFFFFFFF, 0xFFFFFFF0, 0x00000000, 0x00000000),
+ E(0xFFFFFFFF, 0xFFFFFFF8, 0x00000000, 0x00000000),
+ E(0xFFFFFFFF, 0xFFFFFFFC, 0x00000000, 0x00000000),
+ E(0xFFFFFFFF, 0xFFFFFFFE, 0x00000000, 0x00000000),
+ E(0xFFFFFFFF, 0xFFFFFFFF, 0x00000000, 0x00000000),
+ E(0xFFFFFFFF, 0xFFFFFFFF, 0x80000000, 0x00000000),
+ E(0xFFFFFFFF, 0xFFFFFFFF, 0xC0000000, 0x00000000),
+ E(0xFFFFFFFF, 0xFFFFFFFF, 0xE0000000, 0x00000000),
+ E(0xFFFFFFFF, 0xFFFFFFFF, 0xF0000000, 0x00000000),
+ E(0xFFFFFFFF, 0xFFFFFFFF, 0xF8000000, 0x00000000),
+ E(0xFFFFFFFF, 0xFFFFFFFF, 0xFC000000, 0x00000000),
+ E(0xFFFFFFFF, 0xFFFFFFFF, 0xFE000000, 0x00000000),
+ E(0xFFFFFFFF, 0xFFFFFFFF, 0xFF000000, 0x00000000),
+ E(0xFFFFFFFF, 0xFFFFFFFF, 0xFF800000, 0x00000000),
+ E(0xFFFFFFFF, 0xFFFFFFFF, 0xFFC00000, 0x00000000),
+ E(0xFFFFFFFF, 0xFFFFFFFF, 0xFFE00000, 0x00000000),
+ E(0xFFFFFFFF, 0xFFFFFFFF, 0xFFF00000, 0x00000000),
+ E(0xFFFFFFFF, 0xFFFFFFFF, 0xFFF80000, 0x00000000),
+ E(0xFFFFFFFF, 0xFFFFFFFF, 0xFFFC0000, 0x00000000),
+ E(0xFFFFFFFF, 0xFFFFFFFF, 0xFFFE0000, 0x00000000),
+ E(0xFFFFFFFF, 0xFFFFFFFF, 0xFFFF0000, 0x00000000),
+ E(0xFFFFFFFF, 0xFFFFFFFF, 0xFFFF8000, 0x00000000),
+ E(0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFC000, 0x00000000),
+ E(0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFE000, 0x00000000),
+ E(0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFF000, 0x00000000),
+ E(0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFF800, 0x00000000),
+ E(0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFC00, 0x00000000),
+ E(0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFE00, 0x00000000),
+ E(0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFF00, 0x00000000),
+ E(0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFF80, 0x00000000),
+ E(0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFC0, 0x00000000),
+ E(0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFE0, 0x00000000),
+ E(0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFF0, 0x00000000),
+ E(0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFF8, 0x00000000),
+ E(0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFC, 0x00000000),
+ E(0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFE, 0x00000000),
+ E(0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0x00000000),
+ E(0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0x80000000),
+ E(0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xC0000000),
+ E(0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xE0000000),
+ E(0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xF0000000),
+ E(0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xF8000000),
+ E(0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFC000000),
+ E(0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFE000000),
+ E(0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFF000000),
+ E(0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFF800000),
+ E(0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFC00000),
+ E(0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFE00000),
+ E(0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFF00000),
+ E(0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFF80000),
+ E(0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFC0000),
+ E(0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFE0000),
+ E(0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFF0000),
+ E(0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFF8000),
+ E(0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFC000),
+ E(0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFE000),
+ E(0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFF000),
+ E(0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFF800),
+ E(0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFC00),
+ E(0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFE00),
+ E(0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFF00),
+ E(0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFF80),
+ E(0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFC0),
+ E(0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFE0),
+ E(0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFF0),
+ E(0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFF8),
+ E(0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFC),
+ E(0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFE),
+ E(0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF),
+};
+EXPORT_SYMBOL(prefixlen_netmask_map);
+
+MODULE_LICENSE("GPL");
diff --git a/net/netfilter/Kconfig b/net/netfilter/Kconfig
index 222aa07..c1a7ea4 100644
--- a/net/netfilter/Kconfig
+++ b/net/netfilter/Kconfig
@@ -27,6 +27,7 @@ config NETFILTER_NETLINK_LOG
config NF_CONNTRACK
tristate "Netfilter connection tracking support"
default m if NETFILTER_ADVANCED=n
+ select NET_PFXLEN
help
Connection tracking keeps a record of what packets have passed
through your machine, in order to figure out how they are related
diff --git a/net/netfilter/xt_conntrack.c b/net/netfilter/xt_conntrack.c
index 0c50b28..0b03605 100644
--- a/net/netfilter/xt_conntrack.c
+++ b/net/netfilter/xt_conntrack.c
@@ -13,6 +13,7 @@
#include <linux/module.h>
#include <linux/skbuff.h>
#include <net/ipv6.h>
+#include <net/pfxlen.h>
#include <linux/netfilter/x_tables.h>
#include <linux/netfilter/xt_conntrack.h>
#include <net/netfilter/nf_conntrack.h>
@@ -132,42 +133,46 @@ conntrack_addrcmp(const union nf_inet_addr *kaddr,
static inline bool
conntrack_mt_origsrc(const struct nf_conn *ct,
- const struct xt_conntrack_mtinfo1 *info,
+ const struct xt_conntrack_mtinfo2 *info,
unsigned int family)
{
return conntrack_addrcmp(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u3,
- &info->origsrc_addr, &info->origsrc_mask, family);
+ &info->origsrc_addr, &prefixlen_netmask_map[info->origsrc_pfx],
+ family);
}
static inline bool
conntrack_mt_origdst(const struct nf_conn *ct,
- const struct xt_conntrack_mtinfo1 *info,
+ const struct xt_conntrack_mtinfo2 *info,
unsigned int family)
{
return conntrack_addrcmp(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.u3,
- &info->origdst_addr, &info->origdst_mask, family);
+ &info->origdst_addr, &prefixlen_netmask_map[info->origdst_pfx],
+ family);
}
static inline bool
conntrack_mt_replsrc(const struct nf_conn *ct,
- const struct xt_conntrack_mtinfo1 *info,
+ const struct xt_conntrack_mtinfo2 *info,
unsigned int family)
{
return conntrack_addrcmp(&ct->tuplehash[IP_CT_DIR_REPLY].tuple.src.u3,
- &info->replsrc_addr, &info->replsrc_mask, family);
+ &info->replsrc_addr, &prefixlen_netmask_map[info->replsrc_pfx],
+ family);
}
static inline bool
conntrack_mt_repldst(const struct nf_conn *ct,
- const struct xt_conntrack_mtinfo1 *info,
+ const struct xt_conntrack_mtinfo2 *info,
unsigned int family)
{
return conntrack_addrcmp(&ct->tuplehash[IP_CT_DIR_REPLY].tuple.dst.u3,
- &info->repldst_addr, &info->repldst_mask, family);
+ &info->repldst_addr, &prefixlen_netmask_map[info->repldst_pfx],
+ family);
}
static inline bool
-ct_proto_port_check(const struct xt_conntrack_mtinfo1 *info,
+ct_proto_port_check(const struct xt_conntrack_mtinfo2 *info,
const struct nf_conn *ct)
{
const struct nf_conntrack_tuple *tuple;
@@ -210,7 +215,7 @@ conntrack_mt(const struct sk_buff *skb, const struct net_device *in,
const void *matchinfo, int offset, unsigned int protoff,
bool *hotdrop)
{
- const struct xt_conntrack_mtinfo1 *info = matchinfo;
+ const struct xt_conntrack_mtinfo2 *info = matchinfo;
enum ip_conntrack_info ctinfo;
const struct nf_conn *ct;
unsigned int statebit;
@@ -289,6 +294,16 @@ conntrack_mt_check(const char *tablename, const void *ip,
const struct xt_match *match, void *matchinfo,
unsigned int hook_mask)
{
+ const struct xt_conntrack_mtinfo2 *info = matchinfo;
+
+ if (match->family == AF_INET && (info->origsrc_pfx > 32 ||
+ info->origdst_pfx > 32 || info->replsrc_pfx > 32 ||
+ info->repldst_pfx > 32))
+ return false;
+ if (match->family == AF_INET6 && (info->origsrc_pfx > 128 ||
+ info->origdst_pfx > 128 || info->replsrc_pfx > 128 ||
+ info->repldst_pfx > 128))
+ return false;
if (nf_ct_l3proto_try_module_get(match->family) < 0) {
printk(KERN_WARNING "can't load conntrack support for "
"proto=%u\n", match->family);
@@ -370,9 +385,9 @@ static struct xt_match conntrack_mt_reg[] __read_mostly = {
},
{
.name = "conntrack",
- .revision = 1,
+ .revision = 2,
.family = AF_INET,
- .matchsize = sizeof(struct xt_conntrack_mtinfo1),
+ .matchsize = sizeof(struct xt_conntrack_mtinfo2),
.match = conntrack_mt,
.checkentry = conntrack_mt_check,
.destroy = conntrack_mt_destroy,
@@ -380,9 +395,9 @@ static struct xt_match conntrack_mt_reg[] __read_mostly = {
},
{
.name = "conntrack",
- .revision = 1,
+ .revision = 2,
.family = AF_INET6,
- .matchsize = sizeof(struct xt_conntrack_mtinfo1),
+ .matchsize = sizeof(struct xt_conntrack_mtinfo2),
.match = conntrack_mt,
.checkentry = conntrack_mt_check,
.destroy = conntrack_mt_destroy,
diff --git a/net/netfilter/xt_hashlimit.c b/net/netfilter/xt_hashlimit.c
index 5418ce5..c3ade12 100644
--- a/net/netfilter/xt_hashlimit.c
+++ b/net/netfilter/xt_hashlimit.c
@@ -26,6 +26,7 @@
#endif
#include <net/net_namespace.h>
+#include <net/pfxlen.h>
#include <linux/netfilter/x_tables.h>
#include <linux/netfilter_ipv4/ip_tables.h>
@@ -466,43 +467,18 @@ static inline void rateinfo_recalc(struct dsthash_ent *dh, unsigned long now)
static inline __be32 maskl(__be32 a, unsigned int l)
{
- return htonl(ntohl(a) & ~(~(u_int32_t)0 >> l));
+ return a & prefixlen_netmask_map[l].ip;
}
#if defined(CONFIG_IP6_NF_IPTABLES) || defined(CONFIG_IP6_NF_IPTABLES_MODULE)
static void hashlimit_ipv6_mask(__be32 *i, unsigned int p)
{
- switch (p) {
- case 0:
- i[0] = i[1] = 0;
- i[2] = i[3] = 0;
- break;
- case 1 ... 31:
- i[0] = maskl(i[0], p);
- i[1] = i[2] = i[3] = 0;
- break;
- case 32:
- i[1] = i[2] = i[3] = 0;
- break;
- case 33 ... 63:
- i[1] = maskl(i[1], p - 32);
- i[2] = i[3] = 0;
- break;
- case 64:
- i[2] = i[3] = 0;
- break;
- case 65 ... 95:
- i[2] = maskl(i[2], p - 64);
- i[3] = 0;
- case 96:
- i[3] = 0;
- break;
- case 97 ... 127:
- i[3] = maskl(i[3], p - 96);
- break;
- case 128:
- break;
- }
+ const union nf_inet_addr *mask = &prefixlen_netmask_map[p];
+
+ i[0] &= mask->ip6[0];
+ i[1] &= mask->ip6[1];
+ i[2] &= mask->ip6[2];
+ i[3] &= mask->ip6[3];
}
#endif
--
1.5.4.4
--
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