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authorPablo Neira Ayuso <pablo@netfilter.org>2017-12-03 21:05:54 +0100
committerPablo Neira Ayuso <pablo@netfilter.org>2018-03-05 16:31:29 +0100
commit6a89efe2c9891fb4b548dcd81cf72417dd2a9eaa (patch)
tree8039f15c2f539cb2ab2de75aaf9ca8df3ed48b1f /src/expr
parenteb58f53372e7475b65f6d7ee2b72507c4580007e (diff)
expr: add flow offload expression
This patch adds the new "flow_offload" expression to select what flows are offloaded to an existing flowtable. Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Diffstat (limited to 'src/expr')
-rw-r--r--src/expr/flow_offload.c184
1 files changed, 184 insertions, 0 deletions
diff --git a/src/expr/flow_offload.c b/src/expr/flow_offload.c
new file mode 100644
index 0000000..a2001c9
--- /dev/null
+++ b/src/expr/flow_offload.c
@@ -0,0 +1,184 @@
+#include "internal.h"
+
+#include <stdio.h>
+#include <stdint.h>
+#include <string.h> /* for memcpy */
+#include <arpa/inet.h>
+#include <errno.h>
+#include <libmnl/libmnl.h>
+#include <linux/netfilter/nf_tables.h>
+#include <libnftnl/rule.h>
+#include <libnftnl/expr.h>
+
+struct nftnl_expr_flow {
+ char *table_name;
+};
+
+static int nftnl_expr_flow_set(struct nftnl_expr *e, uint16_t type,
+ const void *data, uint32_t data_len)
+{
+ struct nftnl_expr_flow *flow = nftnl_expr_data(e);
+
+ switch (type) {
+ case NFTNL_EXPR_FLOW_TABLE_NAME:
+ flow->table_name = strdup((const char *)data);
+ if (!flow->table_name)
+ return -1;
+ break;
+ default:
+ return -1;
+ }
+ return 0;
+}
+
+static const void *nftnl_expr_flow_get(const struct nftnl_expr *e,
+ uint16_t type, uint32_t *data_len)
+{
+ struct nftnl_expr_flow *flow = nftnl_expr_data(e);
+
+ switch(type) {
+ case NFTNL_EXPR_FLOW_TABLE_NAME:
+ *data_len = strlen(flow->table_name) + 1;
+ return flow->table_name;
+ }
+ return NULL;
+}
+
+static int nftnl_expr_flow_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_FLOW_MAX) < 0)
+ return MNL_CB_OK;
+
+ switch(type) {
+ case NFTA_FLOW_TABLE_NAME:
+ if (mnl_attr_validate(attr, MNL_TYPE_STRING) < 0)
+ abi_breakage();
+ break;
+ }
+
+ tb[type] = attr;
+ return MNL_CB_OK;
+}
+
+static void nftnl_expr_flow_build(struct nlmsghdr *nlh,
+ const struct nftnl_expr *e)
+{
+ struct nftnl_expr_flow *flow = nftnl_expr_data(e);
+
+ if (e->flags & (1 << NFTNL_EXPR_FLOW_TABLE_NAME))
+ mnl_attr_put_strz(nlh, NFTA_FLOW_TABLE_NAME, flow->table_name);
+}
+
+static int nftnl_expr_flow_parse(struct nftnl_expr *e, struct nlattr *attr)
+{
+ struct nftnl_expr_flow *flow = nftnl_expr_data(e);
+ struct nlattr *tb[NFTA_FLOW_MAX+1] = {};
+ int ret = 0;
+
+ if (mnl_attr_parse_nested(attr, nftnl_expr_flow_cb, tb) < 0)
+ return -1;
+
+ if (tb[NFTA_FLOW_TABLE_NAME]) {
+ flow->table_name =
+ strdup(mnl_attr_get_str(tb[NFTA_FLOW_TABLE_NAME]));
+ if (!flow->table_name)
+ return -1;
+ e->flags |= (1 << NFTNL_EXPR_FLOW_TABLE_NAME);
+ }
+
+ return ret;
+}
+
+static int
+nftnl_expr_flow_json_parse(struct nftnl_expr *e, json_t *root,
+ struct nftnl_parse_err *err)
+{
+#ifdef JSON_PARSING
+ const char *table_name;
+
+ table_name = nftnl_jansson_parse_str(root, "flowtable", err);
+ if (table_name != NULL)
+ nftnl_expr_set_str(e, NFTNL_EXPR_FLOW_TABLE_NAME, table_name);
+
+ return 0;
+#else
+ errno = EOPNOTSUPP;
+ return -1;
+#endif
+}
+
+static int nftnl_expr_flow_export(char *buf, size_t size,
+ const struct nftnl_expr *e, int type)
+{
+ struct nftnl_expr_flow *l = nftnl_expr_data(e);
+ NFTNL_BUF_INIT(b, buf, size);
+
+ if (e->flags & (1 << NFTNL_EXPR_FLOW_TABLE_NAME))
+ nftnl_buf_str(&b, type, l->table_name, SET);
+
+ return nftnl_buf_done(&b);
+}
+
+static int nftnl_expr_flow_snprintf_default(char *buf, size_t size,
+ const struct nftnl_expr *e)
+{
+ int remain = size, offset = 0, ret;
+ struct nftnl_expr_flow *l = nftnl_expr_data(e);
+
+ ret = snprintf(buf, remain, "flowtable %s ", l->table_name);
+ SNPRINTF_BUFFER_SIZE(ret, remain, offset);
+
+ return offset;
+}
+
+static int nftnl_expr_flow_snprintf(char *buf, size_t size, uint32_t type,
+ uint32_t flags, const struct nftnl_expr *e)
+{
+ switch(type) {
+ case NFTNL_OUTPUT_DEFAULT:
+ return nftnl_expr_flow_snprintf_default(buf, size, e);
+ case NFTNL_OUTPUT_XML:
+ case NFTNL_OUTPUT_JSON:
+ return nftnl_expr_flow_export(buf, size, e, type);
+ default:
+ break;
+ }
+ return -1;
+}
+
+static void nftnl_expr_flow_free(const struct nftnl_expr *e)
+{
+ struct nftnl_expr_flow *flow = nftnl_expr_data(e);
+
+ xfree(flow->table_name);
+}
+
+static bool nftnl_expr_flow_cmp(const struct nftnl_expr *e1,
+ const struct nftnl_expr *e2)
+{
+ struct nftnl_expr_flow *l1 = nftnl_expr_data(e1);
+ struct nftnl_expr_flow *l2 = nftnl_expr_data(e2);
+ bool eq = true;
+
+ if (e1->flags & (1 << NFTNL_EXPR_FLOW_TABLE_NAME))
+ eq &= !strcmp(l1->table_name, l2->table_name);
+
+ return eq;
+}
+
+struct expr_ops expr_ops_flow = {
+ .name = "flow_offload",
+ .alloc_len = sizeof(struct nftnl_expr_flow),
+ .max_attr = NFTA_FLOW_MAX,
+ .free = nftnl_expr_flow_free,
+ .cmp = nftnl_expr_flow_cmp,
+ .set = nftnl_expr_flow_set,
+ .get = nftnl_expr_flow_get,
+ .parse = nftnl_expr_flow_parse,
+ .build = nftnl_expr_flow_build,
+ .snprintf = nftnl_expr_flow_snprintf,
+ .json_parse = nftnl_expr_flow_json_parse,
+};