iptables: add libxt_cgroup frontend
This patch adds the user space extension/frontend for process matching
based on cgroups from the kernel patch entitled "netfilter: xtables:
lightweight process control group matching".
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
diff --git a/extensions/libxt_cgroup.c b/extensions/libxt_cgroup.c
new file mode 100644
index 0000000..e304e33
--- /dev/null
+++ b/extensions/libxt_cgroup.c
@@ -0,0 +1,67 @@
+#include <stdio.h>
+#include <xtables.h>
+#include <linux/netfilter/xt_cgroup.h>
+
+enum {
+ O_CGROUP = 0,
+};
+
+static void cgroup_help(void)
+{
+ printf(
+"cgroup match options:\n"
+"[!] --cgroup fwid Match cgroup fwid\n");
+}
+
+static const struct xt_option_entry cgroup_opts[] = {
+ {
+ .name = "cgroup",
+ .id = O_CGROUP,
+ .type = XTTYPE_UINT32,
+ .flags = XTOPT_INVERT | XTOPT_MAND | XTOPT_PUT,
+ XTOPT_POINTER(struct xt_cgroup_info, id)
+ },
+ XTOPT_TABLEEND,
+};
+
+static void cgroup_parse(struct xt_option_call *cb)
+{
+ struct xt_cgroup_info *cgroupinfo = cb->data;
+
+ xtables_option_parse(cb);
+ if (cb->invert)
+ cgroupinfo->invert = true;
+}
+
+static void
+cgroup_print(const void *ip, const struct xt_entry_match *match, int numeric)
+{
+ const struct xt_cgroup_info *info = (void *) match->data;
+
+ printf(" cgroup %s%u", info->invert ? "! ":"", info->id);
+}
+
+static void cgroup_save(const void *ip, const struct xt_entry_match *match)
+{
+ const struct xt_cgroup_info *info = (void *) match->data;
+
+ printf("%s --cgroup %u", info->invert ? " !" : "", info->id);
+}
+
+static struct xtables_match cgroup_match = {
+ .family = NFPROTO_UNSPEC,
+ .name = "cgroup",
+ .version = XTABLES_VERSION,
+ .size = XT_ALIGN(sizeof(struct xt_cgroup_info)),
+ .userspacesize = XT_ALIGN(sizeof(struct xt_cgroup_info)),
+ .help = cgroup_help,
+ .print = cgroup_print,
+ .save = cgroup_save,
+ .x6_parse = cgroup_parse,
+ .x6_options = cgroup_opts,
+};
+
+void _init(void)
+{
+ xtables_register_match(&cgroup_match);
+}
diff --git a/extensions/libxt_cgroup.man b/extensions/libxt_cgroup.man
new file mode 100644
index 0000000..456a031
--- /dev/null
+++ b/extensions/libxt_cgroup.man
@@ -0,0 +1,15 @@
+.TP
+[\fB!\fP] \fB\-\-cgroup\fP \fIfwid\fP
+Match corresponding cgroup for this packet.
+
+Can be used to assign particular firewall policies for aggregated
+task/jobs on the system. This allows for more fine-grained firewall
+policies that only match for a subset of the system's processes.
+fwid is the maker set through the net_cls cgroup's id.
+.PP
+Example:
+.PP
+iptables \-A OUTPUT \-p tcp \-\-sport 80 \-m cgroup ! \-\-cgroup 1
+\-j DROP
+.PP
+Available since Linux 3.14.
diff --git a/include/linux/netfilter/xt_cgroup.h b/include/linux/netfilter/xt_cgroup.h
new file mode 100644
index 0000000..943d3a0
--- /dev/null
+++ b/include/linux/netfilter/xt_cgroup.h
@@ -0,0 +1,11 @@
+#ifndef _XT_CGROUP_H
+#define _XT_CGROUP_H
+
+#include <linux/types.h>
+
+struct xt_cgroup_info {
+ __u32 id;
+ __u32 invert;
+};
+
+#endif /* _XT_CGROUP_H */
