Add user-space code for the TPROXY target.
Signed-off-by: KOVACS Krisztian <hidden@xxxxxxxxxx>
---
extensions/libxt_TPROXY.c | 151 +++++++++++++++++++++++++++++++++++
extensions/libxt_TPROXY.man | 21 +++++
include/linux/netfilter/xt_TPROXY.h | 14 +++
3 files changed, 186 insertions(+), 0 deletions(-)
create mode 100644 extensions/libxt_TPROXY.c
create mode 100644 extensions/libxt_TPROXY.man
create mode 100644 include/linux/netfilter/xt_TPROXY.h
diff --git a/extensions/libxt_TPROXY.c b/extensions/libxt_TPROXY.c
new file mode 100644
index 0000000..0f910f4
--- /dev/null
+++ b/extensions/libxt_TPROXY.c
@@ -0,0 +1,151 @@
+/*
+ * Shared library add-on to iptables to add TPROXY target support.
+ *
+ * Copyright (C) 2002-2008 BalaBit IT Ltd.
+ */
+#include <getopt.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+#include <limits.h>
+
+#include <iptables.h>
+#include <xtables.h>
+#include <linux/netfilter/x_tables.h>
+#include <linux/netfilter/xt_TPROXY.h>
+
+static const struct option tproxy_tg_opts[] = {
+ { .name = "on-port", .has_arg = 1, .val = '1'},
+ { .name = "on-ip", .has_arg = 1, .val = '2'},
+ { .name = "tproxy-mark", .has_arg = 1, .val = '3'},
+ {NULL},
+};
+
+enum {
+ PARAM_ONPORT = 1 << 0,
+ PARAM_ONIP = 1 << 1,
+ PARAM_MARK = 1 << 2,
+};
+
+static void tproxy_tg_help(void)
+{
+ printf(
+"TPROXY target options:\n"
+" --on-port port Redirect connection to port, or the original port if 0\n"
+" --on-ip ip Optionally redirect to the given IP\n"
+" --tproxy-mark value[/mask] Mark packets with the given value/mask\n\n");
+}
+
+static void parse_tproxy_lport(const char *s, struct xt_tproxy_target_info *info)
+{
+ unsigned int lport;
+
+ if (string_to_number(s, 0, 65535, &lport) != -1)
+ info->lport = htons(lport);
+ else
+ param_act(P_BAD_VALUE, "TPROXY", "--on-port", s);
+}
+
+static void parse_tproxy_laddr(const char *s, struct xt_tproxy_target_info *info)
+{
+ struct in_addr *laddr;
+
+ if ((laddr = numeric_to_ipaddr(s)) == NULL)
+ param_act(P_BAD_VALUE, "TPROXY", "--on-ip", s);
+
+ info->laddr = laddr->s_addr;
+}
+
+static void parse_tproxy_mark(char *s, struct xt_tproxy_target_info *info)
+{
+ unsigned int value, mask = ~0U;
+ char *end;
+
+ if (!strtonum(s, &end, &value, 0, UINT_MAX))
+ param_act(P_BAD_VALUE, "TPROXY", "--tproxy-mark", s);
+ if (*end == '/')
+ if (!strtonum(end + 1, &end, &mask, 0, UINT_MAX))
+ param_act(P_BAD_VALUE, "TPROXY", "--tproxy-mark", s);
+ if (*end != '\0')
+ param_act(P_BAD_VALUE, "TPROXY", "--tproxy-mark", s);
+
+ info->mark_mask = mask;
+ info->mark_value = value;
+}
+
+static int tproxy_tg_parse(int c, char **argv, int invert, unsigned int *flags,
+ const void *entry, struct xt_entry_target **target)
+{
+ struct xt_tproxy_target_info *tproxyinfo = (void *)(*target)->data;
+
+ switch (c) {
+ case '1':
+ param_act(P_ONLY_ONCE, "TPROXY", "--on-port", *flags & PARAM_ONPORT);
+ param_act(P_NO_INVERT, "TPROXY", "--on-port", invert);
+ parse_tproxy_lport(optarg, tproxyinfo);
+ *flags |= PARAM_ONPORT;
+ return 1;
+ case '2':
+ param_act(P_ONLY_ONCE, "TPROXY", "--on-ip", *flags & PARAM_ONIP);
+ param_act(P_NO_INVERT, "TPROXY", "--on-ip", invert);
+ parse_tproxy_laddr(optarg, tproxyinfo);
+ *flags |= PARAM_ONIP;
+ return 1;
+ case '3':
+ param_act(P_ONLY_ONCE, "TPROXY", "--tproxy-mark", *flags & PARAM_MARK);
+ param_act(P_NO_INVERT, "TPROXY", "--tproxy-mark", invert);
+ parse_tproxy_mark(optarg, tproxyinfo);
+ *flags |= PARAM_MARK;
+ return 1;
+ }
+
+ return 0;
+}
+
+static void tproxy_tg_check(unsigned int flags)
+{
+ if (!(flags & PARAM_ONPORT))
+ exit_error(PARAMETER_PROBLEM,
+ "TPROXY target: Parameter --on-port is required");
+}
+
+static void tproxy_tg_print(const void *ip, const struct xt_entry_target *target,
+ int numeric)
+{
+ const struct xt_tproxy_target_info *info = (const void *)target->data;
+ printf("TPROXY redirect %s:%u mark 0x%x/0x%x",
+ ipaddr_to_numeric((const struct in_addr *)&info->laddr),
+ ntohs(info->lport), (unsigned int)info->mark_value,
+ (unsigned int)info->mark_mask);
+}
+
+static void tproxy_tg_save(const void *ip, const struct xt_entry_target *target)
+{
+ const struct xt_tproxy_target_info *info = (const void *)target->data;
+
+ printf("--on-port %u ", ntohs(info->lport));
+ printf("--on-ip %s ",
+ ipaddr_to_numeric((const struct in_addr *)&info->laddr));
+ printf("--tproxy-mark 0x%x/0x%x ",
+ (unsigned int)info->mark_value, (unsigned int)info->mark_mask);
+}
+
+static struct xtables_target tproxy_tg_reg = {
+ .name = "TPROXY",
+ .family = AF_INET,
+ .version = XTABLES_VERSION,
+ .size = XT_ALIGN(sizeof(struct xt_tproxy_target_info)),
+ .userspacesize = XT_ALIGN(sizeof(struct xt_tproxy_target_info)),
+ .help = tproxy_tg_help,
+ .parse = tproxy_tg_parse,
+ .final_check = tproxy_tg_check,
+ .print = tproxy_tg_print,
+ .save = tproxy_tg_save,
+ .extra_opts = tproxy_tg_opts,
+};
+
+void _init(void)
+{
+ xtables_register_target(&tproxy_tg_reg);
+}
diff --git a/extensions/libxt_TPROXY.man b/extensions/libxt_TPROXY.man
new file mode 100644
index 0000000..f17848c
--- /dev/null
+++ b/extensions/libxt_TPROXY.man
@@ -0,0 +1,21 @@
+This target is only valid in the \fBmangle\fR table, in the \fBPREROUTING\fR
+chain and user-defined chains which are only called from this chain. It
+redirects the packet to a local socket without changing the packet header in
+any way. It can also change the mark value which can then be used in advanced
+routing rules.
+It takes three options:
+.TP
+\fB--on-port\fR \fIport\fR
+This specifies a destination port to use. It is a required option, 0 means the
+new destination port is the same as the original. This is only valid if the
+rule also specifies \fB-p tcp\fR or \fB-p udp\fR.
+.TP
+\fB--on-ip\fR \fIaddress\fR
+This specifies a destination address to use. By default the address is the IP
+address of the incoming interface. This is only valid if the rule also
+specifies \fB-p tcp\fR or \fR-p udp\fR.
+.TP
+\fB--tproxy-mark\fR \fIvalue\fR[\fB/\fR\fImask\fR]
+Marks packets with the given value/mask. The fwmark value set here can be used
+by advanced routing. (Required for transparent proxying to work: otherwise
+these packets will get forwarded, which is probably not what you want.)
diff --git a/include/linux/netfilter/xt_TPROXY.h b/include/linux/netfilter/xt_TPROXY.h
new file mode 100644
index 0000000..152e8f9
--- /dev/null
+++ b/include/linux/netfilter/xt_TPROXY.h
@@ -0,0 +1,14 @@
+#ifndef _XT_TPROXY_H_target
+#define _XT_TPROXY_H_target
+
+/* TPROXY target is capable of marking the packet to perform
+ * redirection. We can get rid of that whenever we get support for
+ * mutliple targets in the same rule. */
+struct xt_tproxy_target_info {
+ u_int32_t mark_mask;
+ u_int32_t mark_value;
+ __be32 laddr;
+ __be16 lport;
+};
+
+#endif /* _XT_TPROXY_H_target */
--
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