extensions: add devgroup match extension

extensions: add devgroup match extension

[Patrick McHardy]

[-- Attachment #1: Type: text/plain, Size: 63 bytes --]

The corresponding userspace extension for the devgroup match.


[-- Attachment #2: libxt_devgroup.diff --]
[-- Type: text/plain, Size: 8206 bytes --]

commit cf1927156166312e5729ff420e5371e1c1a8fc5e
Author: Patrick McHardy <kaber@trash.net>
Date:   Fri Jan 28 19:29:08 2011 +0100

    extensions: add devgroup match extension
    
    Signed-off-by: Patrick McHardy <kaber@trash.net>

diff --git a/extensions/libxt_devgroup.c b/extensions/libxt_devgroup.c
new file mode 100644
index 0000000..385373e
--- /dev/null
+++ b/extensions/libxt_devgroup.c
@@ -0,0 +1,294 @@
+/* Shared library add-on to iptables to add devgroup matching support. */
+#include <stdbool.h>
+#include <stdio.h>
+#include <netdb.h>
+#include <string.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <ctype.h>
+#include <getopt.h>
+#include <xtables.h>
+#include <linux/netfilter/xt_devgroup.h>
+
+static void devgroup_help(void)
+{
+	printf(
+"devgroup match options:\n"
+"[!] --src-group value[/mask]\n"
+"[!] --dst-group value[/mask]\n"
+"				Match devgroup\n");
+}
+
+enum {
+	XT_DEVGROUP_OPT_SRCGROUP = 1,
+	XT_DEVGROUP_OPT_DSTGROUP,
+};
+
+static const struct option devgroup_opts[] = {
+	{ .name = "src-group", .has_arg = true, .val = XT_DEVGROUP_OPT_SRCGROUP },
+	{ .name = "dst-group", .has_arg = true, .val = XT_DEVGROUP_OPT_DSTGROUP },
+	XT_GETOPT_TABLEEND,
+};
+
+struct devgroupname {
+	unsigned int		id;
+	char			*name;
+	int			len;
+	struct devgroupname	*next;
+};
+
+/* array of devgroups from /etc/iproute2/group_map */
+static struct devgroupname *devgroups;
+/* 1 if loading failed */
+static int rdberr;
+
+static void load_devgroups(void)
+{
+	const char* rfnm = "/etc/iproute2/group_map";
+	char buf[512];
+	FILE *fil;
+	char *cur, *nxt;
+	int id;
+	struct devgroupname *oldnm = NULL, *newnm = NULL;
+
+	fil = fopen(rfnm, "r");
+	if (!fil) {
+		rdberr = 1;
+		return;
+	}
+
+	while (fgets(buf, sizeof(buf), fil)) {
+		cur = buf;
+		while ((*cur == ' ') || (*cur == '\t'))
+			cur++;
+		if ((*cur == '#') || (*cur == '\n') || (*cur == 0))
+			continue;
+
+		/* iproute2 allows hex and dec format */
+		errno = 0;
+		id = strtoul(cur, &nxt, strncmp(cur, "0x", 2) ? 10 : 16);
+		if ((nxt == cur) || errno)
+			continue;
+
+		/* same boundaries as in iproute2 */
+		if (id < 0 || id > 255)
+			continue;
+		cur = nxt;
+
+		if (!isspace(*cur))
+			continue;
+		while ((*cur == ' ') || (*cur == '\t'))
+			cur++;
+		if ((*cur == '#') || (*cur == '\n') || (*cur == 0))
+			continue;
+		nxt = cur;
+		while ((*nxt != 0) && !isspace(*nxt))
+			nxt++;
+		if (nxt == cur)
+			continue;
+
+		/* found valid data */
+		newnm = malloc(sizeof(struct devgroupname));
+		if (newnm == NULL) {
+			perror("libxt_devgroup: malloc failed");
+			exit(1);
+		}
+		newnm->id = id;
+		newnm->len = nxt - cur;
+		newnm->name = malloc(newnm->len + 1);
+		if (newnm->name == NULL) {
+			perror("libxt_devgroup: malloc failed");
+			exit(1);
+		}
+		strncpy(newnm->name, cur, newnm->len);
+		newnm->name[newnm->len] = 0;
+		newnm->next = NULL;
+
+		if (oldnm)
+			oldnm->next = newnm;
+		else
+			devgroups = newnm;
+		oldnm = newnm;
+	}
+
+	fclose(fil);
+}
+
+/* get devgroup id for name, -1 if error/not found */
+static int devgroup_name2id(const char* name)
+{
+	struct devgroupname* cur;
+
+	if ((devgroups == NULL) && (rdberr == 0))
+		load_devgroups();
+	cur = devgroups;
+	if (cur == NULL)
+		return -1;
+	while (cur) {
+		if (!strncmp(name, cur->name, cur->len + 1))
+			return cur->id;
+		cur = cur->next;
+	}
+	return -1;
+}
+
+/* get devgroup name for id, NULL if error/not found */
+static const char *devgroup_id2name(int id)
+{
+	struct devgroupname* cur;
+
+	if ((devgroups == NULL) && (rdberr == 0))
+		load_devgroups();
+	cur = devgroups;
+	if (cur == NULL)
+		return NULL;
+	while (cur) {
+		if (id == cur->id)
+			return cur->name;
+		cur = cur->next;
+	}
+	return NULL;
+}
+
+static int devgroup_parse(int c, char **argv, int invert, unsigned int *flags,
+                       const void *entry, struct xt_entry_match **match)
+{
+	struct xt_devgroup_info *info = (struct xt_devgroup_info *)(*match)->data;
+	unsigned int id;
+	char *end;
+
+	switch (c) {
+	case XT_DEVGROUP_OPT_SRCGROUP:
+		xtables_check_inverse(optarg, &invert, &optind, 0, argv);
+		end = optarg;
+		info->src_group = strtoul(optarg, &end, 0);
+		if (end != optarg && (*end == '/' || *end == '\0')) {
+			if (*end == '/')
+				info->src_mask = strtoul(end+1, &end, 0);
+			else
+				info->src_mask = 0xffffffff;
+			if (*end != '\0' || end == optarg)
+				xtables_error(PARAMETER_PROBLEM,
+					      "Bad src-group value `%s'",
+					      optarg);
+		} else {
+			id = devgroup_name2id(optarg);
+			if (id == -1)
+				xtables_error(PARAMETER_PROBLEM,
+					      "Device group `%s' not found",
+					      optarg);
+			info->src_group = id;
+			info->src_mask  = 0xffffffff;
+		}
+		info->flags |= XT_DEVGROUP_MATCH_SRC;
+		if (invert)
+			info->flags |= XT_DEVGROUP_INVERT_SRC;
+		*flags |= c;
+		break;
+	case XT_DEVGROUP_OPT_DSTGROUP:
+		xtables_check_inverse(optarg, &invert, &optind, 0, argv);
+		end = optarg;
+		info->dst_group = strtoul(optarg, &end, 0);
+		if (end != optarg && (*end == '/' || *end == '\0')) {
+			if (*end == '/')
+				info->dst_mask = strtoul(end+1, &end, 0);
+			else
+				info->dst_mask = 0xffffffff;
+			if (*end != '\0' || end == optarg)
+				xtables_error(PARAMETER_PROBLEM,
+					      "Bad dst-group value `%s'",
+					      optarg);
+		} else {
+			id = devgroup_name2id(optarg);
+			if (id == -1)
+				xtables_error(PARAMETER_PROBLEM,
+					      "Device group `%s' not found",
+					      optarg);
+			info->dst_group = id;
+			info->dst_mask  = 0xffffffff;
+		}
+		info->flags |= XT_DEVGROUP_MATCH_DST;
+		if (invert)
+			info->flags |= XT_DEVGROUP_INVERT_DST;
+		*flags |= c;
+		break;
+	}
+	return 1;
+}
+
+static void
+print_devgroup(unsigned int id, unsigned int mask, int numeric)
+{
+	const char *name = NULL;
+
+	if (mask != 0xffffffff)
+		printf("0x%x/0x%x ", id, mask);
+	else {
+		if (numeric == 0)
+			name = devgroup_id2name(id);
+		if (name)
+			printf("%s ", name);
+		else
+			printf("0x%x ", id);
+	}
+}
+
+static void devgroup_show(const char *pfx, const struct xt_devgroup_info *info,
+			  int numeric)
+{
+	if (info->flags & XT_DEVGROUP_MATCH_SRC) {
+		if (info->flags & XT_DEVGROUP_INVERT_SRC)
+			printf("! ");
+		printf("%ssrc-group ", pfx);
+		print_devgroup(info->src_group, info->src_mask, numeric);
+	}
+
+	if (info->flags & XT_DEVGROUP_MATCH_DST) {
+		if (info->flags & XT_DEVGROUP_INVERT_DST)
+			printf("! ");
+		printf("%sdst-group ", pfx);
+		print_devgroup(info->src_group, info->src_mask, numeric);
+	}
+}
+
+static void devgroup_print(const void *ip, const struct xt_entry_match *match,
+                        int numeric)
+{
+	const struct xt_devgroup_info *info = (const void *)match->data;
+
+	devgroup_show("", info, numeric);
+}
+
+static void devgroup_save(const void *ip, const struct xt_entry_match *match)
+{
+	const struct xt_devgroup_info *info = (const void *)match->data;
+
+	devgroup_show("--", info, 0);
+}
+
+static void devgroup_check(unsigned int flags)
+{
+	if (!flags)
+		xtables_error(PARAMETER_PROBLEM,
+			      "devgroup match: You must specify either "
+			      "'--src-group' or '--dst-group'");
+}
+
+static struct xtables_match devgroup_mt_reg = {
+	.name		= "devgroup",
+	.version	= XTABLES_VERSION,
+	.family		= NFPROTO_UNSPEC,
+	.size		= XT_ALIGN(sizeof(struct xt_devgroup_info)),
+	.userspacesize	= XT_ALIGN(sizeof(struct xt_devgroup_info)),
+	.help		= devgroup_help,
+	.parse		= devgroup_parse,
+	.final_check	= devgroup_check,
+	.print		= devgroup_print,
+	.save		= devgroup_save,
+	.extra_opts	= devgroup_opts,
+};
+
+void _init(void)
+{
+	xtables_register_match(&devgroup_mt_reg);
+}
diff --git a/include/linux/netfilter/xt_devgroup.h b/include/linux/netfilter/xt_devgroup.h
new file mode 100644
index 0000000..1babde0
--- /dev/null
+++ b/include/linux/netfilter/xt_devgroup.h
@@ -0,0 +1,21 @@
+#ifndef _XT_DEVGROUP_H
+#define _XT_DEVGROUP_H
+
+#include <linux/types.h>
+
+enum xt_devgroup_flags {
+	XT_DEVGROUP_MATCH_SRC	= 0x1,
+	XT_DEVGROUP_INVERT_SRC	= 0x2,
+	XT_DEVGROUP_MATCH_DST	= 0x4,
+	XT_DEVGROUP_INVERT_DST	= 0x8,
+};
+
+struct xt_devgroup_info {
+	__u32	flags;
+	__u32	src_group;
+	__u32	src_mask;
+	__u32	dst_group;
+	__u32	dst_mask;
+};
+
+#endif /* _XT_DEVGROUP_H */