[WIP,libnftnl] expr: add osf support

Message ID 20180712103614.2615-1-ffmancera@riseup.net
State RFC
Delegated to: Pablo Neira
Headers show
Series
  • [WIP,libnftnl] expr: add osf support
Related show

Commit Message

Fernando Fernandez Mancera July 12, 2018, 10:36 a.m.
Signed-off-by: Fernando Fernandez Mancera <ffmancera@riseup.net>
---
 include/libnftnl/expr.h             |   7 +
 include/linux/netfilter/nf_tables.h |  20 +++
 src/Makefile.am                     |   1 +
 src/expr/osf.c                      | 262 ++++++++++++++++++++++++++++
 src/expr_ops.c                      |   2 +
 5 files changed, 292 insertions(+)
 create mode 100644 src/expr/osf.c

Patch

diff --git a/include/libnftnl/expr.h b/include/libnftnl/expr.h
index 219104e..4ee71a5 100644
--- a/include/libnftnl/expr.h
+++ b/include/libnftnl/expr.h
@@ -268,6 +268,13 @@  enum {
 	NFTNL_EXPR_OBJREF_SET_ID,
 };
 
+enum {
+	NFTNL_EXPR_OSF_GENRE	= NFTNL_EXPR_BASE,
+	NFTNL_EXPR_OSF_FLAGS,
+	NFTNL_EXPR_OSF_LOGLEVEL,
+	NFTNL_EXPR_OSF_TTL,
+};
+
 #ifdef __cplusplus
 } /* extern "C" */
 #endif
diff --git a/include/linux/netfilter/nf_tables.h b/include/linux/netfilter/nf_tables.h
index 91449ef..d96636f 100644
--- a/include/linux/netfilter/nf_tables.h
+++ b/include/linux/netfilter/nf_tables.h
@@ -122,6 +122,8 @@  enum nf_tables_msg_types {
 	NFT_MSG_NEWFLOWTABLE,
 	NFT_MSG_GETFLOWTABLE,
 	NFT_MSG_DELFLOWTABLE,
+	NFT_MSG_NEWOSF,
+	NFT_MSG_DELOSF,
 	NFT_MSG_MAX,
 };
 
@@ -929,6 +931,24 @@  enum nft_socket_keys {
 };
 #define NFT_SOCKET_MAX	(__NFT_SOCKET_MAX - 1)
 
+/**
+ * enum nft_osf_attributes - nf_tables osf expression netlink attributes
+ *
+ * @NFTA_OSF_GENRE: OS to match
+ * @NFTA_OSF_FLAGS: Valid flags
+ * @NFTA_OSF_LOGLEVEL: different log levels
+ * @NFTA_OSF_TTL: different checks on TTL
+ */
+enum nft_osf_attributes {
+	NFTA_OSF_UNSPEC,
+	NFTA_OSF_GENRE,
+	NFTA_OSF_FLAGS,
+	NFTA_OSF_LOGLEVEL,
+	NFTA_OSF_TTL,
+	__NFTA_OSF_MAX,
+};
+#define NFTA_OSF_MAX (__NFTA_OSF_MAX - 1)
+
 /**
  * enum nft_ct_keys - nf_tables ct expression keys
  *
diff --git a/src/Makefile.am b/src/Makefile.am
index c66a257..bdc10f7 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -56,6 +56,7 @@  libnftnl_la_SOURCES = utils.c		\
 		      expr/redir.c	\
 		      expr/hash.c	\
 		      expr/socket.c	\
+		      expr/osf.c	\
 		      obj/counter.c	\
 		      obj/ct_helper.c	\
 		      obj/quota.c	\
diff --git a/src/expr/osf.c b/src/expr/osf.c
new file mode 100644
index 0000000..a560629
--- /dev/null
+++ b/src/expr/osf.c
@@ -0,0 +1,262 @@ 
+#include <stdio.h>
+#include <stdint.h>
+#include <string.h>
+#include <arpa/inet.h>
+#include <errno.h>
+#include <linux/netfilter/nf_tables.h>
+
+#include "internal.h"
+#include <libmnl/libmnl.h>
+#include <libnftnl/expr.h>
+#include <libnftnl/rule.h>
+
+#define OSF_GENRE_SIZE	32
+
+struct nftnl_expr_osf {
+	char	*genre;
+	__u32	flags;
+	__u32	loglevel;
+	__u32	ttl;
+	__u32	len;
+};
+
+static int nftnl_expr_osf_set(struct nftnl_expr *e, uint16_t type,
+			      const void *data, uint32_t data_len)
+{
+	struct nftnl_expr_osf *osf = nftnl_expr_data(e);
+
+	switch(type) {
+	case NFTNL_EXPR_OSF_GENRE:
+		osf->genre = strdup(data);
+		if (!osf->genre)
+			return -1;
+		break;
+	case NFTNL_EXPR_OSF_FLAGS:
+		osf->len = *((unsigned int *)data);
+		break;
+	case NFTNL_EXPR_OSF_LOGLEVEL:
+		osf->loglevel = *((unsigned int *)data);
+		break;
+	case NFTNL_EXPR_OSF_TTL:
+		osf->ttl = *((unsigned int *)data);
+		break;
+	}
+	return 0;
+}
+
+static const void *
+nftnl_expr_osf_get(const struct nftnl_expr *e, uint16_t type,
+		   uint32_t *data_len)
+{
+	struct nftnl_expr_osf *osf = nftnl_expr_data(e);
+
+	switch(type) {
+	case NFTNL_EXPR_OSF_GENRE:
+		*data_len = strlen(osf->genre)+1;
+		return osf->genre;
+	case NFTNL_EXPR_OSF_FLAGS:
+		*data_len = sizeof(osf->flags);
+		return &osf->flags;
+	case NFTNL_EXPR_OSF_LOGLEVEL:
+		*data_len = sizeof(osf->loglevel);
+		return &osf->loglevel;
+	case NFTNL_EXPR_OSF_TTL:
+		*data_len = sizeof(osf->ttl);
+		return &osf->ttl;
+	}
+	return NULL;
+}
+
+static int nftnl_expr_osf_cb(const struct nlattr *attr, void *data)
+{
+	const struct nlattr **tb = data;
+	int type = mnl_attr_get_type(attr);
+
+	if (mnl_attr_type_valid(attr, NFTA_OSF_MAX) < 0)
+		return MNL_CB_OK;
+
+	switch(type) {
+	case NFTNL_EXPR_OSF_GENRE:
+		if (mnl_attr_validate(attr, MNL_TYPE_STRING) < 0)
+			abi_breakage();
+		break;
+	case NFTNL_EXPR_OSF_FLAGS:
+	case NFTNL_EXPR_OSF_LOGLEVEL:
+	case NFTNL_EXPR_OSF_TTL:
+		if (mnl_attr_validate(attr, MNL_TYPE_U32) < 0)
+			abi_breakage();
+		break;
+	}
+
+	tb[type] = attr;
+	return MNL_CB_OK;
+}
+
+static void
+nftnl_expr_osf_build(struct nlmsghdr *nlh, const struct nftnl_expr *e)
+{
+	struct nftnl_expr_osf *osf = nftnl_expr_data(e);
+
+	if (e->flags & (1 << NFTNL_EXPR_OSF_GENRE))
+		mnl_attr_put_str(nlh, NFTNL_EXPR_OSF_GENRE, osf->genre);
+	if (e->flags & (1 << NFTNL_EXPR_OSF_FLAGS))
+		mnl_attr_put_u32(nlh, NFTNL_EXPR_OSF_FLAGS, htonl(osf->flags));
+	if (e->flags & (1 << NFTNL_EXPR_OSF_LOGLEVEL))
+		mnl_attr_put_u32(nlh, NFTNL_EXPR_OSF_LOGLEVEL, htonl(osf->loglevel));
+	if (e->flags & (1 << NFTNL_EXPR_OSF_TTL))
+		mnl_attr_put_u32(nlh, NFTNL_EXPR_OSF_TTL, htonl(osf->ttl));
+}
+
+static int
+nftnl_expr_osf_parse(struct nftnl_expr *e, struct nlattr *attr)
+{
+	struct nftnl_expr_osf *osf = nftnl_expr_data(e);
+	struct nlattr *tb[NFTA_OSF_MAX + 1] = {};
+
+	if (mnl_attr_parse_nested(attr, nftnl_expr_osf_cb, tb) < 0)
+		return -1;
+
+	if (tb[NFTA_OSF_GENRE]) {
+		if (osf->genre)
+			xfree(osf->genre);
+
+		osf->genre = strdup(mnl_attr_get_str(tb[NFTA_OSF_GENRE]));
+		if (!osf->genre)
+			return -1;
+		e->flags |= (1 << NFTNL_EXPR_OSF_GENRE);
+	}
+	if (tb[NFTA_OSF_FLAGS]) {
+		osf->flags = ntohl(mnl_attr_get_u32(tb[NFTA_OSF_FLAGS]));
+		e->flags |= (1 << NFTNL_EXPR_OSF_FLAGS);
+	}
+	if (tb[NFTA_OSF_LOGLEVEL]) {
+		osf->loglevel = ntohl(mnl_attr_get_u32(tb[NFTA_OSF_LOGLEVEL]));
+		e->flags |= (1 << NFTNL_EXPR_OSF_LOGLEVEL);
+	}
+	if (tb[NFTA_OSF_TTL]) {
+		osf->ttl = ntohl(mnl_attr_get_u32(tb[NFTA_OSF_TTL]));
+		e->flags |= (1 << NFTNL_EXPR_OSF_TTL);
+	}
+
+	return 0;
+}
+
+static int nftnl_expr_osf_json_parse(struct nftnl_expr *e, json_t *root,
+				     struct nftnl_parse_err *err)
+{
+#ifdef JSON_PARSING
+	const char *genre;
+	uint32_t flags;
+	uint32_t loglevel;
+	uint32_t ttl;
+
+	genre = nftnl_jansson_parse_str(root, "genre", err);
+	if (genre != NULL)
+		nftnl_expr_set_str(e, NFTNL_EXPR_OSF_GENRE, genre);
+
+	flags = nftnl_jansson_parse_u32(root, "flags", err);
+	if (flags != NULL)
+		nftnl_expr_set_u32(e, NFTNL_EXPR_OSF_FLAGS, flags);
+
+	loglevel = nftnl_jansson_parse_u32(root, "loglevel", err);
+	if(loglevel != NULL)
+		nftnl_expr_set_u32(e, NFTNL_EXPR_OSF_LOGLEVEL, loglevel);
+
+	ttl = nftnl_jansson_parse_u32(root, "ttl", err);
+	if(ttl != NULL)
+		nftnl_expr_set_u32(e, NFTNL_EXPR_OSF_TTL, ttl);
+
+	return 0;
+#else
+	errno = EOPNOTSUPP;
+	return -1;
+#endif
+}
+
+static int nftnl_expr_osf_snprintf_default(char *buf, size_t size,
+					   const struct nftnl_expr *e)
+{
+	struct nftnl_expr_osf *osf = nftnl_expr_data(e);
+	int ret, offset = 0, len = size;
+
+	if (e->flags & (1 << NFTNL_EXPR_OSF_GENRE)) {
+		ret = snprintf(buf, len, "%s", osf->genre);
+		SNPRINTF_BUFFER_SIZE(ret, len, offset);
+	}
+
+	return offset;
+}
+
+static int nftnl_expr_osf_export(char *buf, size_t size,
+				 const struct nftnl_expr *e, int type)
+{
+	struct nftnl_expr_osf *osf = nftnl_expr_data(e);
+	NFTNL_BUF_INIT(b, buf, size);
+
+	if (e->flags & (1 << NFTNL_EXPR_OSF_GENRE))
+		nftnl_buf_str(&b, type, osf->genre, "genre");
+	if (e->flags & (1 << NFTNL_EXPR_OSF_FLAGS))
+		nftnl_buf_u32(&b, type, osf->flags, "flags");
+	if (e->flags & (1 << NFTNL_EXPR_OSF_LOGLEVEL))
+		nftnl_buf_u32(&b, type, osf->loglevel, "loglevel");
+	if (e->flags & (1 << NFTNL_EXPR_OSF_TTL))
+		nftnl_buf_u32(&b, type, osf->ttl, "ttl");
+
+	return nftnl_buf_done(&b);
+}
+
+static int
+nftnl_expr_osf_snprintf(char *buf, size_t len, uint32_t type,
+			uint32_t flags, const struct nftnl_expr *e)
+{
+	switch(type) {
+	case NFTNL_OUTPUT_DEFAULT:
+		return nftnl_expr_osf_snprintf_default(buf, len, e);
+	case NFTNL_OUTPUT_XML:
+	case NFTNL_OUTPUT_JSON:
+		return nftnl_expr_osf_export(buf, len, e, type);
+	default:
+		break;
+	}
+	return -1;
+}
+
+static void nftnl_expr_osf_free(const struct nftnl_expr *e)
+{
+	struct nftnl_expr_osf *osf = nftnl_expr_data(e);
+
+	xfree(osf->genre);
+}
+
+static bool nftnl_expr_osf_cmp(const struct nftnl_expr *e1,
+			       const struct nftnl_expr *e2)
+{
+	struct nftnl_expr_osf *l1 = nftnl_expr_data(e1);
+	struct nftnl_expr_osf *l2 = nftnl_expr_data(e2);
+	bool eq = true;
+
+	if (e1->flags & (1 << NFTNL_EXPR_OSF_GENRE))
+		eq &= strncmp(l1->genre, l2->genre, OSF_GENRE_SIZE);
+	if (e1->flags & (1 << NFTNL_EXPR_OSF_FLAGS))
+		eq &= (l1->flags == l2->flags);
+	if (e1->flags & (1 << NFTNL_EXPR_OSF_LOGLEVEL))
+		eq &= (l1->loglevel == l2->loglevel);
+	if (e1->flags & (1 << NFTNL_EXPR_OSF_TTL))
+		eq &= (l1->ttl == l2->ttl);
+
+	return eq;
+}
+
+struct expr_ops expr_ops_osf = {
+	.name		= "osf",
+	.alloc_len	= sizeof(struct nftnl_expr_osf),
+	.max_attr	= NFTA_OSF_MAX,
+	.free		= nftnl_expr_osf_free,
+	.cmp		= nftnl_expr_osf_cmp,
+	.set		= nftnl_expr_osf_set,
+	.get		= nftnl_expr_osf_get,
+	.parse		= nftnl_expr_osf_parse,
+	.build		= nftnl_expr_osf_build,
+	.snprintf	= nftnl_expr_osf_snprintf,
+	.json_parse	= nftnl_expr_osf_json_parse,
+};
diff --git a/src/expr_ops.c b/src/expr_ops.c
index cbb2a1b..f400246 100644
--- a/src/expr_ops.c
+++ b/src/expr_ops.c
@@ -36,6 +36,7 @@  extern struct expr_ops expr_ops_hash;
 extern struct expr_ops expr_ops_fib;
 extern struct expr_ops expr_ops_flow;
 extern struct expr_ops expr_ops_socket;
+extern struct expr_ops expr_ops_osf;
 
 static struct expr_ops expr_ops_notrack = {
 	.name	= "notrack",
@@ -75,6 +76,7 @@  static struct expr_ops *expr_ops[] = {
 	&expr_ops_objref,
 	&expr_ops_flow,
 	&expr_ops_socket,
+	&expr_ops_osf,
 	NULL,
 };