Import libxt_TCPOPTSTRIP into iptables.
Signed-off-by: Jan Engelhardt <jengelh@xxxxxxxxxxxxxxx>
Cc: Sven Schnelle <svens@xxxxxxxxxxxx>
---
extensions/Makefile | 2
extensions/libxt_TCPOPTSTRIP.c | 211 +++++++++++++++++++++++++++++++
extensions/libxt_TCPOPTSTRIP.man | 7 +
include/linux/netfilter/xt_TCPOPTSTRIP.h | 13 +
4 files changed, 232 insertions(+), 1 deletion(-)
Index: iptables-modules/extensions/Makefile
===================================================================
--- iptables-modules.orig/extensions/Makefile
+++ iptables-modules/extensions/Makefile
@@ -7,7 +7,7 @@
#
PF_EXT_SLIB:=ah addrtype conntrack ecn icmp iprange policy realm recent tos ttl unclean CLUSTERIP DNAT ECN LOG MASQUERADE MIRROR NETMAP REDIRECT REJECT SAME SNAT TOS TTL ULOG
PF6_EXT_SLIB:=ah dst eui64 frag hbh hl icmp6 ipv6header mh policy rt HL LOG REJECT
-PFX_EXT_SLIB:=connbytes connmark connlimit comment dccp dscp esp hashlimit helper length limit mac mark multiport owner physdev pkttype quota sctp state statistic standard string tcp tcpmss time u32 udp CLASSIFY CONNMARK DSCP MARK NFLOG NFQUEUE NOTRACK TCPMSS TEE TRACE
+PFX_EXT_SLIB:=connbytes connmark connlimit comment dccp dscp esp hashlimit helper length limit mac mark multiport owner physdev pkttype quota sctp state statistic standard string tcp tcpmss time u32 udp CLASSIFY CONNMARK DSCP MARK NFLOG NFQUEUE NOTRACK TCPMSS TEE TCPOPTSTRIP TRACE
PF_EXT_SELINUX_SLIB:=
PF6_EXT_SELINUX_SLIB:=
Index: iptables-modules/extensions/libxt_TCPOPTSTRIP.c
===================================================================
--- /dev/null
+++ iptables-modules/extensions/libxt_TCPOPTSTRIP.c
@@ -0,0 +1,211 @@
+/*
+ * Shared library add-on to iptables to add TCPOPTSTRIP target support.
+ * Copyright (c) 2007 Sven Schnelle <svens@xxxxxxxxxxxx>
+ * Copyright © Jan Engelhardt <jengelh@xxxxxxxxxxxxxxx>
+ */
+#include <getopt.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+#include <xtables.h>
+#include <linux/netfilter/x_tables.h>
+#include <linux/netfilter/xt_TCPOPTSTRIP.h>
+#ifndef TCPOPT_MD5SIG
+# define TCPOPT_MD5SIG 19
+#endif
+
+enum {
+ FLAG_STRIP = 1 << 0,
+};
+
+struct tcp_optionmap {
+ const char *name, *desc;
+ const int option;
+};
+
+static const struct option tcpoptstrip_tg_opts[] = {
+ {.name = "strip-options", .has_arg = true, .val = 's'},
+ {},
+};
+
+static const struct tcp_optionmap tcp_optionmap[] = {
+ {"wscale", "Window scale", TCPOPT_WINDOW},
+ {"mss", "Maximum Segment Size", TCPOPT_MAXSEG},
+ {"sack-permitted", "SACK permitted", TCPOPT_SACK_PERMITTED},
+ {"sack", "Selective ACK", TCPOPT_SACK},
+ {"timestamp", "Timestamp", TCPOPT_TIMESTAMP},
+ {"md5", "MD5 signature", TCPOPT_MD5SIG},
+ {NULL},
+};
+
+static void tcpoptstrip_tg_help(void)
+{
+ const struct tcp_optionmap *w;
+
+ printf(
+"TCPOPTSTRIP target options:\n"
+" --strip-options value strip specified TCP options denoted by value\n"
+" (separated by comma) from TCP header\n"
+" Instead of the numeric value, you can also use the following names:\n"
+ );
+
+ for (w = tcp_optionmap; w->name != NULL; ++w)
+ printf(" %-14s strip \"%s\" option\n", w->name, w->desc);
+}
+
+static void tcpoptstrip_tg_init(struct xt_entry_target *t)
+{
+ struct xt_tcpoptstrip_target_info *info = (void *)t->data;
+
+ /* strictly necessary? play safe for now. */
+ memset(info->strip_bmap, 0, sizeof(info->strip_bmap));
+}
+
+static void parse_list(struct xt_tcpoptstrip_target_info *info, char *arg)
+{
+ unsigned int option;
+ char *p;
+ int i;
+
+ while (true) {
+ p = strchr(arg, ',');
+ if (p != NULL)
+ *p = '\0';
+
+ option = 0;
+ for (i = 0; tcp_optionmap[i].name != NULL; ++i)
+ if (strcmp(tcp_optionmap[i].name, arg) == 0) {
+ option = tcp_optionmap[i].option;
+ break;
+ }
+
+ if (option == 0 && string_to_number(arg, 0, 255, &option) == -1)
+ exit_error(PARAMETER_PROBLEM,
+ "Bad TCP option value \"%s\"", arg);
+
+ if (option < 2)
+ exit_error(PARAMETER_PROBLEM,
+ "Option value may not be 0 or 1");
+
+ if (tcpoptstrip_test_bit(info->strip_bmap, option))
+ exit_error(PARAMETER_PROBLEM,
+ "Option \"%s\" already specified", arg);
+
+ tcpoptstrip_set_bit(info->strip_bmap, option);
+ if (p == NULL)
+ break;
+ arg = p + 1;
+ }
+}
+
+static int tcpoptstrip_tg_parse(int c, char **argv, int invert,
+ unsigned int *flags, const void *entry,
+ struct xt_entry_target **target)
+{
+ struct xt_tcpoptstrip_target_info *info = (void *)(*target)->data;
+
+ switch (c) {
+ case 's':
+ if (*flags & FLAG_STRIP)
+ exit_error(PARAMETER_PROBLEM,
+ "You can specify --strip-options only once");
+ parse_list(info, optarg);
+ *flags |= FLAG_STRIP;
+ return true;
+ }
+
+ return false;
+}
+
+static void tcpoptstrip_tg_check(unsigned int flags)
+{
+ if (flags == 0)
+ exit_error(PARAMETER_PROBLEM,
+ "TCPOPTSTRIP: --strip-options parameter required");
+}
+
+static void
+tcpoptstrip_print_list(const struct xt_tcpoptstrip_target_info *info,
+ bool numeric)
+{
+ unsigned int i, j;
+ const char *name;
+ bool first = true;
+
+ for (i = 0; i < 256; ++i) {
+ if (!tcpoptstrip_test_bit(info->strip_bmap, i))
+ continue;
+ if (!first)
+ printf(",");
+
+ first = false;
+ name = NULL;
+ if (!numeric)
+ for (j = 0; tcp_optionmap[j].name != NULL; ++j)
+ if (tcp_optionmap[j].option == i)
+ name = tcp_optionmap[j].name;
+
+ if (name != NULL)
+ printf("%s", name);
+ else
+ printf("%u", i);
+ }
+}
+
+static void
+tcpoptstrip_tg_print(const void *ip, const struct xt_entry_target *target,
+ int numeric)
+{
+ const struct xt_tcpoptstrip_target_info *info =
+ (const void *)target->data;
+
+ printf("TCPOPTSTRIP options ");
+ tcpoptstrip_print_list(info, numeric);
+}
+
+static void
+tcpoptstrip_tg_save(const void *ip, const struct xt_entry_target *target)
+{
+ const struct xt_tcpoptstrip_target_info *info =
+ (const void *)target->data;
+
+ printf("--strip-options ");
+ tcpoptstrip_print_list(info, true);
+}
+
+static struct xtables_target tcpoptstrip_tg_reg = {
+ .name = "TCPOPTSTRIP",
+ .family = AF_INET,
+ .version = IPTABLES_VERSION,
+ .size = XT_ALIGN(sizeof(struct xt_tcpoptstrip_target_info)),
+ .userspacesize = XT_ALIGN(sizeof(struct xt_tcpoptstrip_target_info)),
+ .help = tcpoptstrip_tg_help,
+ .init = tcpoptstrip_tg_init,
+ .parse = tcpoptstrip_tg_parse,
+ .final_check = tcpoptstrip_tg_check,
+ .print = tcpoptstrip_tg_print,
+ .save = tcpoptstrip_tg_save,
+ .extra_opts = tcpoptstrip_tg_opts,
+};
+
+static struct xtables_target tcpoptstrip_tg6_reg = {
+ .name = "TCPOPTSTRIP",
+ .family = AF_INET6,
+ .version = IPTABLES_VERSION,
+ .size = XT_ALIGN(sizeof(struct xt_tcpoptstrip_target_info)),
+ .userspacesize = XT_ALIGN(sizeof(struct xt_tcpoptstrip_target_info)),
+ .help = tcpoptstrip_tg_help,
+ .init = tcpoptstrip_tg_init,
+ .parse = tcpoptstrip_tg_parse,
+ .final_check = tcpoptstrip_tg_check,
+ .print = tcpoptstrip_tg_print,
+ .save = tcpoptstrip_tg_save,
+ .extra_opts = tcpoptstrip_tg_opts,
+};
+
+void _init(void)
+{
+ xtables_register_target(&tcpoptstrip_tg_reg);
+ xtables_register_target(&tcpoptstrip_tg6_reg);
+}
Index: iptables-modules/extensions/libxt_TCPOPTSTRIP.man
===================================================================
--- /dev/null
+++ iptables-modules/extensions/libxt_TCPOPTSTRIP.man
@@ -0,0 +1,7 @@
+This target will strip TCP options off a TCP packet. (It will actually replace
+them by NO-OPs.) As such, you will need to add the \fB-p tcp\fR parameters.
+.TP
+\fB--strip-options\fR \fIoption\fR[\fB,\fR\fI...\fR]
+Strip the given option(s). The options may be specified by TCP option number or
+by symbolic name. The list of recognized options can be obtained by calling
+iptables with \fB-j TCPOPTSTRIP -h\fR.
Index: iptables-modules/include/linux/netfilter/xt_TCPOPTSTRIP.h
===================================================================
--- /dev/null
+++ iptables-modules/include/linux/netfilter/xt_TCPOPTSTRIP.h
@@ -0,0 +1,13 @@
+#ifndef _XT_TCPOPTSTRIP_H
+#define _XT_TCPOPTSTRIP_H
+
+#define tcpoptstrip_set_bit(bmap, idx) \
+ (bmap[(idx) >> 5] |= 1UL << (idx & 31))
+#define tcpoptstrip_test_bit(bmap, idx) \
+ (((1UL << (idx & 31)) & bmap[(idx) >> 5]) != 0)
+
+struct xt_tcpoptstrip_target_info {
+ u_int32_t strip_bmap[8];
+};
+
+#endif /* _XT_TCPOPTSTRIP_H */
-
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