[PATCH 3/3] libxt_ipvs: user-space lib for netfilter matcher xt_ipvs

From: Hannes Eder
Date: Wed Sep 02 2009 - 10:42:10 EST


The user-space library for the netfilter matcher xt_ipvs.

Signed-off-by: Hannes Eder <heder@xxxxxxxxxx>
---

configure.ac | 11 +
extensions/libxt_ipvs.c | 349 +++++++++++++++++++++++++++++++++++++
extensions/libxt_ipvs.man | 21 ++
include/linux/netfilter/xt_ipvs.h | 23 ++
4 files changed, 401 insertions(+), 3 deletions(-)
create mode 100644 extensions/libxt_ipvs.c
create mode 100644 extensions/libxt_ipvs.man
create mode 100644 include/linux/netfilter/xt_ipvs.h

diff --git a/configure.ac b/configure.ac
index bc74efe..e55ab43 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1,4 +1,3 @@
-
AC_INIT([iptables], [1.4.4])

# See libtool.info "Libtool's versioning system"
@@ -47,12 +46,18 @@ AC_ARG_WITH([pkgconfigdir], AS_HELP_STRING([--with-pkgconfigdir=PATH],
[Path to the pkgconfig directory [[LIBDIR/pkgconfig]]]),
[pkgconfigdir="$withval"], [pkgconfigdir='${libdir}/pkgconfig'])

-AC_CHECK_HEADER([linux/dccp.h])
-
blacklist_modules="";
+
+AC_CHECK_HEADER([linux/dccp.h])
if test "$ac_cv_header_linux_dccp_h" != "yes"; then
blacklist_modules="$blacklist_modules dccp";
fi;
+
+AC_CHECK_HEADER([linux/ip_vs.h])
+if test "$ac_cv_header_linux_ip_vs_h" != "yes"; then
+ blacklist_modules="$blacklist_modules ipvs";
+fi;
+
AC_SUBST([blacklist_modules])

AM_CONDITIONAL([ENABLE_STATIC], [test "$enable_static" = "yes"])
diff --git a/extensions/libxt_ipvs.c b/extensions/libxt_ipvs.c
new file mode 100644
index 0000000..9fd007f
--- /dev/null
+++ b/extensions/libxt_ipvs.c
@@ -0,0 +1,349 @@
+/* Shared library add-on to iptables to add IPVS matching.
+ *
+ * Detailed doc is in the kernel module source net/netfilter/xt_ipvs.c
+ *
+ * Author: Hannes Eder <heder@xxxxxxxxxx>
+ */
+#include <sys/types.h>
+#include <assert.h>
+#include <ctype.h>
+#include <errno.h>
+#include <getopt.h>
+#include <netdb.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <xtables.h>
+#include <linux/ip_vs.h>
+#include <linux/netfilter/xt_ipvs.h>
+
+static const struct option ipvs_mt_opts[] = {
+ { .name = "ipvs", .has_arg = false, .val = '0' },
+ { .name = "vproto", .has_arg = true, .val = '1' },
+ { .name = "vaddr", .has_arg = true, .val = '2' },
+ { .name = "vport", .has_arg = true, .val = '3' },
+ { .name = "vdir", .has_arg = true, .val = '4' },
+ { .name = "vmethod", .has_arg = true, .val = '5' },
+ { .name = NULL }
+};
+
+static void ipvs_mt_help(void)
+{
+ printf(
+"IPVS match options:\n"
+"[!] --ipvs packet belongs to an IPVS connection\n"
+"\n"
+"Any of the following options implies --ipvs (even negated)\n"
+"[!] --vproto protocol VIP protocol to match; by number or name,\n"
+" e.g. \"tcp\"\n"
+"[!] --vaddr address[/mask] VIP address to match\n"
+"[!] --vport port VIP port to match; by number or name,\n"
+" e.g. \"http\"\n"
+" --vdir {ORIGINAL|REPLY} flow direction of packet\n"
+"[!] --vmethod {GATE|IPIP|MASQ} IPVS forwarding method used\n"
+ );
+}
+
+static void ipvs_mt_parse_addr_and_mask(const char *arg,
+ union nf_inet_addr *address,
+ union nf_inet_addr *mask,
+ unsigned int family)
+{
+ struct in_addr *addr = NULL;
+ struct in6_addr *addr6 = NULL;
+ unsigned int naddrs = 0;
+
+ if (family == NFPROTO_IPV4) {
+ xtables_ipparse_any(arg, &addr, &mask->in, &naddrs);
+ if (naddrs > 1)
+ xtables_error(PARAMETER_PROBLEM,
+ "multiple IP addresses not allowed");
+ if (naddrs == 1)
+ memcpy(&address->in, addr, sizeof(*addr));
+ } else if (family == NFPROTO_IPV6) {
+ xtables_ip6parse_any(arg, &addr6, &mask->in6, &naddrs);
+ if (naddrs > 1)
+ xtables_error(PARAMETER_PROBLEM,
+ "multiple IP addresses not allowed");
+ if (naddrs == 1)
+ memcpy(&address->in6, addr6, sizeof(*addr6));
+ } else {
+ /* Hu? */
+ assert(false);
+ }
+}
+
+/* Function which parses command options; returns true if it ate an option */
+static int ipvs_mt_parse(int c, char **argv, int invert, unsigned int *flags,
+ const void *entry, struct xt_entry_match **match,
+ unsigned int family)
+{
+ struct xt_ipvs *data = (void *)(*match)->data;
+ char *p = NULL;
+ u_int8_t op = 0;
+
+ if ('0' <= c && c <= '5') {
+ int ops[] = {
+ XT_IPVS_IPVS_PROPERTY,
+ XT_IPVS_PROTO,
+ XT_IPVS_VADDR,
+ XT_IPVS_VPORT,
+ XT_IPVS_DIR,
+ XT_IPVS_METHOD
+ };
+ op = ops[c - '0'];
+ } else
+ return 0;
+
+ if (*flags & op & XT_IPVS_ONCE_MASK)
+ goto multiple_use;
+
+ switch (c) {
+ case '0': /* --ipvs */
+ /* Nothing to do here. */
+ break;
+
+ case '1': /* --vproto */
+ /* Canonicalize into lower case */
+ for (p = optarg; *p != '\0'; ++p)
+ *p = tolower(*p);
+
+ data->l4proto = xtables_parse_protocol(optarg);
+ break;
+
+ case '2': /* --vaddr */
+ ipvs_mt_parse_addr_and_mask(optarg, &data->vaddr,
+ &data->vmask, family);
+ break;
+
+ case '3': /* --vport */
+ data->vport = htons(xtables_parse_port(optarg, "tcp"));
+ break;
+
+ case '4': /* --vdir */
+ xtables_param_act(XTF_NO_INVERT, "ipvs", "--vdir", invert);
+ if (strcasecmp(optarg, "ORIGINAL") == 0) {
+ data->bitmask |= XT_IPVS_DIR;
+ data->invert &= ~XT_IPVS_DIR;
+ } else if (strcasecmp(optarg, "REPLY") == 0) {
+ data->bitmask |= XT_IPVS_DIR;
+ data->invert |= XT_IPVS_DIR;
+ } else {
+ xtables_param_act(XTF_BAD_VALUE,
+ "ipvs", "--vdir", optarg);
+ }
+ break;
+
+ case '5': /* --vmethod */
+ if (strcasecmp(optarg, "GATE") == 0)
+ data->fwd_method = IP_VS_CONN_F_DROUTE;
+ else if (strcasecmp(optarg, "IPIP") == 0)
+ data->fwd_method = IP_VS_CONN_F_TUNNEL;
+ else if (strcasecmp(optarg, "MASQ") == 0)
+ data->fwd_method = IP_VS_CONN_F_MASQ;
+ else
+ xtables_param_act(XTF_BAD_VALUE,
+ "ipvs", "--vmethod", optarg);
+ break;
+
+ default:
+ /* Hu? How did we come here? */
+ assert(false);
+ return 0;
+ }
+
+ if (op & XT_IPVS_ONCE_MASK) {
+ if (data->invert & XT_IPVS_IPVS_PROPERTY)
+ xtables_error(PARAMETER_PROBLEM,
+ "! --ipvs cannot be together with"
+ " other options");
+ data->bitmask |= XT_IPVS_IPVS_PROPERTY;
+ }
+
+ data->bitmask |= op;
+ if (invert)
+ data->invert |= op;
+ *flags |= op;
+ return 1;
+
+multiple_use:
+ xtables_error(PARAMETER_PROBLEM,
+ "multiple use of the same IPVS option is not allowed");
+}
+
+static int ipvs_mt4_parse(int c, char **argv, int invert, unsigned int *flags,
+ const void *entry, struct xt_entry_match **match)
+{
+ return ipvs_mt_parse(c, argv, invert, flags, entry, match,
+ NFPROTO_IPV4);
+}
+
+static int ipvs_mt6_parse(int c, char **argv, int invert, unsigned int *flags,
+ const void *entry, struct xt_entry_match **match)
+{
+ return ipvs_mt_parse(c, argv, invert, flags, entry, match,
+ NFPROTO_IPV6);
+}
+
+static void ipvs_mt_check(unsigned int flags)
+{
+ if (flags == 0)
+ xtables_error(PARAMETER_PROBLEM,
+ "IPVS: At least one option is required");
+}
+
+/* Shamelessly copied from libxt_conntrack.c */
+static void ipvs_mt_dump_addr(const union nf_inet_addr *addr,
+ const union nf_inet_addr *mask,
+ unsigned int family, bool numeric)
+{
+ char buf[BUFSIZ];
+
+ if (family == NFPROTO_IPV4) {
+ if (!numeric && addr->ip == 0) {
+ printf("anywhere ");
+ return;
+ }
+ if (numeric)
+ strcpy(buf, xtables_ipaddr_to_numeric(&addr->in));
+ else
+ strcpy(buf, xtables_ipaddr_to_anyname(&addr->in));
+ strcat(buf, xtables_ipmask_to_numeric(&mask->in));
+ printf("%s ", buf);
+ } else if (family == NFPROTO_IPV6) {
+ if (!numeric && addr->ip6[0] == 0 && addr->ip6[1] == 0 &&
+ addr->ip6[2] == 0 && addr->ip6[3] == 0) {
+ printf("anywhere ");
+ return;
+ }
+ if (numeric)
+ strcpy(buf, xtables_ip6addr_to_numeric(&addr->in6));
+ else
+ strcpy(buf, xtables_ip6addr_to_anyname(&addr->in6));
+ strcat(buf, xtables_ip6mask_to_numeric(&mask->in6));
+ printf("%s ", buf);
+ }
+}
+
+static void ipvs_mt_dump(const void *ip, const struct xt_ipvs *data,
+ unsigned int family, bool numeric, const char *prefix)
+{
+ if (data->bitmask == XT_IPVS_IPVS_PROPERTY) {
+ if (data->invert & XT_IPVS_IPVS_PROPERTY)
+ printf("! ");
+ printf("%sipvs ", prefix);
+ }
+
+ if (data->bitmask & XT_IPVS_PROTO) {
+ if (data->invert & XT_IPVS_PROTO)
+ printf("! ");
+ printf("%sproto %u ", prefix, data->l4proto);
+ }
+
+ if (data->bitmask & XT_IPVS_VADDR) {
+ if (data->invert & XT_IPVS_VADDR)
+ printf("! ");
+
+ printf("%svaddr ", prefix);
+ ipvs_mt_dump_addr(&data->vaddr, &data->vmask, family, numeric);
+ }
+
+ if (data->bitmask & XT_IPVS_VPORT) {
+ if (data->invert & XT_IPVS_VPORT)
+ printf("! ");
+
+ printf("%svport %u ", prefix, ntohs(data->vport));
+ }
+
+ if (data->bitmask & XT_IPVS_DIR) {
+ if (data->invert & XT_IPVS_DIR)
+ printf("%svdir REPLY ", prefix);
+ else
+ printf("%svdir ORIGINAL ", prefix);
+ }
+
+ if (data->bitmask & XT_IPVS_METHOD) {
+ if (data->invert & XT_IPVS_METHOD)
+ printf("! ");
+
+ printf("%svmethod ", prefix);
+ switch (data->fwd_method) {
+ case IP_VS_CONN_F_DROUTE:
+ printf("GATE ");
+ break;
+ case IP_VS_CONN_F_TUNNEL:
+ printf("IPIP ");
+ break;
+ case IP_VS_CONN_F_MASQ:
+ printf("MASQ ");
+ break;
+ default:
+ /* Hu? */
+ printf("UNKNOWN ");
+ break;
+ }
+ }
+}
+
+static void ipvs_mt4_print(const void *ip, const struct xt_entry_match *match,
+ int numeric)
+{
+ const struct xt_ipvs *data = (const void *)match->data;
+ ipvs_mt_dump(ip, data, NFPROTO_IPV4, numeric, "");
+}
+
+static void ipvs_mt6_print(const void *ip, const struct xt_entry_match *match,
+ int numeric)
+{
+ const struct xt_ipvs *data = (const void *)match->data;
+ ipvs_mt_dump(ip, data, NFPROTO_IPV6, numeric, "");
+}
+
+static void ipvs_mt4_save(const void *ip, const struct xt_entry_match *match)
+{
+ const struct xt_ipvs *data = (const void *)match->data;
+ ipvs_mt_dump(ip, data, NFPROTO_IPV4, true, "--");
+}
+
+static void ipvs_mt6_save(const void *ip, const struct xt_entry_match *match)
+{
+ const struct xt_ipvs *data = (const void *)match->data;
+ ipvs_mt_dump(ip, data, NFPROTO_IPV6, true, "--");
+}
+
+static struct xtables_match ipvs_matches_reg[] = {
+ {
+ .version = XTABLES_VERSION,
+ .name = "ipvs",
+ .revision = 0,
+ .family = NFPROTO_IPV4,
+ .size = XT_ALIGN(sizeof(struct xt_ipvs)),
+ .userspacesize = XT_ALIGN(sizeof(struct xt_ipvs)),
+ .help = ipvs_mt_help,
+ .parse = ipvs_mt4_parse,
+ .final_check = ipvs_mt_check,
+ .print = ipvs_mt4_print,
+ .save = ipvs_mt4_save,
+ .extra_opts = ipvs_mt_opts,
+ },
+ {
+ .version = XTABLES_VERSION,
+ .name = "ipvs",
+ .revision = 0,
+ .family = NFPROTO_IPV6,
+ .size = XT_ALIGN(sizeof(struct xt_ipvs)),
+ .userspacesize = XT_ALIGN(sizeof(struct xt_ipvs)),
+ .help = ipvs_mt_help,
+ .parse = ipvs_mt6_parse,
+ .final_check = ipvs_mt_check,
+ .print = ipvs_mt6_print,
+ .save = ipvs_mt6_save,
+ .extra_opts = ipvs_mt_opts,
+ },
+};
+
+void _init(void)
+{
+ xtables_register_matches(ipvs_matches_reg,
+ ARRAY_SIZE(ipvs_matches_reg));
+}
diff --git a/extensions/libxt_ipvs.man b/extensions/libxt_ipvs.man
new file mode 100644
index 0000000..7fe915f
--- /dev/null
+++ b/extensions/libxt_ipvs.man
@@ -0,0 +1,21 @@
+Match IPVS connection properties.
+.TP
+[\fB!\fR] \fB\-\-ipvs\fP
+packet belongs to an IPVS connection
+.TP
+Any of the following options implies \-\-ipvs (even negated)
+.TP
+[\fB!\fR] \fB\-\-vproto\fP \fIprotocol\fP
+VIP protocol to match; by number or name, e.g. "tcp"
+.TP
+[\fB!\fR] \fB\-\-vaddr\fP \fIaddress\fP[\fB/\fP\fImask\fP]
+VIP address to match
+.TP
+[\fB!\fR] \fB\-\-vport\fP \fIport\fP
+VIP port to match; by number or name, e.g. "http"
+.TP
+\fB\-\-vdir\fP {\fBORIGINAL\fP|\fBREPLY\fP}
+flow direction of packet
+.TP
+[\fB!\fR] \fB\-\-vmethod\fP {\fBGATE\fP|\fBIPIP\fP|\fBMASQ\fP}
+IPVS forwarding method used
diff --git a/include/linux/netfilter/xt_ipvs.h b/include/linux/netfilter/xt_ipvs.h
new file mode 100644
index 0000000..eb09759
--- /dev/null
+++ b/include/linux/netfilter/xt_ipvs.h
@@ -0,0 +1,23 @@
+#ifndef _XT_IPVS_H
+#define _XT_IPVS_H 1
+
+#define XT_IPVS_IPVS_PROPERTY 0x01 /* this is implied by all other options */
+#define XT_IPVS_PROTO 0x02
+#define XT_IPVS_VADDR 0x04
+#define XT_IPVS_VPORT 0x08
+#define XT_IPVS_DIR 0x10
+#define XT_IPVS_METHOD 0x20
+#define XT_IPVS_MASK (0x40 - 1)
+#define XT_IPVS_ONCE_MASK (XT_IPVS_MASK & ~XT_IPVS_IPVS_PROPERTY)
+
+struct xt_ipvs {
+ union nf_inet_addr vaddr, vmask;
+ __be16 vport;
+ __u16 l4proto;
+ __u16 fwd_method;
+
+ __u8 invert;
+ __u8 bitmask;
+};
+
+#endif /* _XT_IPVS_H */

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