Adding upstream version 8.4.4.upstream/8.4.4upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 342 insertions, 0 deletions

diff --git a/lib/frrscript.h b/lib/frrscript.h
new file mode 100644
index 0000000..7fa01f7
--- /dev/null
+++ b/lib/frrscript.h
@@ -0,0 +1,342 @@
+/* Scripting foo
+ * Copyright (C) 2020  NVIDIA Corporation
+ * Quentin Young
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the Free
+ * Software Foundation; either version 2 of the License, or (at your option)
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; see the file COPYING; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+#ifndef __FRRSCRIPT_H__
+#define __FRRSCRIPT_H__
+
+#include <zebra.h>
+
+#ifdef HAVE_SCRIPTING
+
+#include <lua.h>
+#include <nexthop.h>
+#include <nexthop_group.h>
+#include "frrlua.h"
+#include "bgpd/bgp_script.h" // for peer and attr encoders/decoders
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* Forward declarations */
+extern struct zebra_dplane_ctx ctx;
+extern void lua_pushzebra_dplane_ctx(lua_State *L,
+				     const struct zebra_dplane_ctx *ctx);
+extern void lua_decode_zebra_dplane_ctx(lua_State *L, int idx,
+					struct zebra_dplane_ctx *ctx);
+
+/*
+ * Script name hash
+ */
+PREDECL_HASH(frrscript_names);
+
+struct frrscript_names_entry {
+	/* Name of a Lua hook call */
+	char function_name[MAXPATHLEN];
+
+	/* Lua script in which to look for it */
+	char script_name[MAXPATHLEN];
+
+	struct frrscript_names_item item;
+};
+
+extern struct frrscript_names_head frrscript_names_hash;
+
+int frrscript_names_hash_cmp(const struct frrscript_names_entry *snhe1,
+			     const struct frrscript_names_entry *snhe2);
+uint32_t frrscript_names_hash_key(const struct frrscript_names_entry *snhe);
+
+DECLARE_HASH(frrscript_names, struct frrscript_names_entry, item,
+	     frrscript_names_hash_cmp, frrscript_names_hash_key);
+
+int frrscript_names_add_function_name(const char *function_name);
+void frrscript_names_destroy(void);
+int frrscript_names_set_script_name(const char *function_name,
+				    const char *script_name);
+char *frrscript_names_get_script_name(const char *function_name);
+
+typedef void (*encoder_func)(lua_State *, const void *);
+typedef void *(*decoder_func)(lua_State *, int);
+
+struct frrscript_codec {
+	const char *typename;
+	encoder_func encoder;
+	decoder_func decoder;
+};
+
+struct lua_function_state {
+	const char *name;
+	lua_State *L;
+};
+
+struct frrscript {
+	/* Script name */
+	char *name;
+
+	/* Hash of Lua function name to Lua function state */
+	struct hash *lua_function_hash;
+};
+
+
+/*
+ * Hash related functions for lua_function_hash
+ */
+
+void *lua_function_alloc(void *arg);
+
+unsigned int lua_function_hash_key(const void *data);
+
+bool lua_function_hash_cmp(const void *d1, const void *d2);
+
+struct frrscript_env {
+	/* Value type */
+	const char *typename;
+
+	/* Binding name */
+	const char *name;
+
+	/* Value */
+	const void *val;
+};
+
+/*
+ * Create new struct frrscript for a Lua script.
+ * This will hold the states for the Lua functions in this script.
+ *
+ * scriptname
+ *     Name of the Lua script file, without the .lua
+ */
+struct frrscript *frrscript_new(const char *scriptname);
+
+/*
+ * Load a function into frrscript, run callback if any
+ */
+int frrscript_load(struct frrscript *fs, const char *function_name,
+		   int (*load_cb)(struct frrscript *));
+
+/*
+ * Delete Lua function states and frrscript
+ */
+void frrscript_delete(struct frrscript *fs);
+
+/*
+ * Register a Lua codec for a type.
+ *
+ * tname
+ *    Name of type; e.g., "peer", "ospf_interface", etc. Chosen at will.
+ *
+ * codec(s)
+ *    Function pointer to codec struct. Encoder function should push a Lua
+ *    table representing the passed argument - which will have the C type
+ *    associated with the chosen 'tname' to the provided stack. The decoder
+ *    function should pop a value from the top of the stack and return a heap
+ *    chunk containing that value. Allocations should be made with MTYPE_TMP.
+ *
+ *    If using the plural function variant, pass a NULL-terminated array.
+ *
+ */
+void frrscript_register_type_codec(struct frrscript_codec *codec);
+void frrscript_register_type_codecs(struct frrscript_codec *codecs);
+
+/*
+ * Initialize scripting subsystem. Call this before anything else.
+ *
+ * scriptdir
+ *    Directory in which to look for scripts
+ */
+void frrscript_init(const char *scriptdir);
+
+/*
+ * On shutdown clean up memory associated with the scripting subsystem
+ */
+void frrscript_fini(void);
+
+/*
+ * This macro is mapped to every (name, value) in frrscript_call,
+ * so this in turn maps them onto their encoders
+ */
+#define ENCODE_ARGS(name, value) ENCODE_ARGS_WITH_STATE(lfs->L, (value))
+
+/*
+ * This macro is also mapped to every (name, value) in frrscript_call, but
+ * not every value can be mapped to its decoder - only those that appear
+ * in the returned table will. To find out if they appear in the returned
+ * table, first pop the value and check if its nil. Only call the decoder
+ * if non-nil.
+ *
+ * At the end, the only thing left on the stack should be the
+ * returned table.
+ */
+#define DECODE_ARGS(name, value)                                               \
+	do {                                                                   \
+		lua_getfield(lfs->L, 1, (name));                               \
+		if (lua_isnil(lfs->L, 2)) {                                    \
+			lua_pop(lfs->L, 1);                                    \
+		} else {                                                       \
+			DECODE_ARGS_WITH_STATE(lfs->L, (value));               \
+		}                                                              \
+		assert(lua_gettop(lfs->L) == 1);                               \
+	} while (0)
+
+/*
+ * Maps the type of value to its encoder/decoder.
+ * Add new mappings here.
+ *
+ * L
+ *    Lua state
+ * scriptdir
+ *    Directory in which to look for scripts
+ */
+#define ENCODE_ARGS_WITH_STATE(L, value)                                       \
+	_Generic((value), \
+int : lua_pushinteger,                                          \
+long long * : lua_pushintegerp,                                 \
+struct prefix * : lua_pushprefix,                               \
+struct interface * : lua_pushinterface,                         \
+struct in_addr * : lua_pushinaddr,                              \
+struct in6_addr * : lua_pushin6addr,                            \
+union sockunion * : lua_pushsockunion,                          \
+time_t * : lua_pushtimet,                                       \
+char * : lua_pushstring_wrapper,                                \
+struct attr * : lua_pushattr,                                   \
+struct peer * : lua_pushpeer,                                   \
+const struct prefix * : lua_pushprefix,                         \
+const struct ipaddr * : lua_pushipaddr,                         \
+const struct ethaddr * : lua_pushethaddr,                       \
+const struct nexthop_group * : lua_pushnexthop_group,           \
+const struct nexthop * : lua_pushnexthop,                       \
+struct zebra_dplane_ctx * : lua_pushzebra_dplane_ctx            \
+)((L), (value))
+
+#define DECODE_ARGS_WITH_STATE(L, value)                                       \
+	_Generic((value), \
+int : lua_decode_integer_noop,                                  \
+long long * : lua_decode_integerp,                              \
+struct prefix * : lua_decode_prefix,                            \
+struct interface * : lua_decode_interface,                      \
+struct in_addr * : lua_decode_inaddr,                           \
+struct in6_addr * : lua_decode_in6addr,                         \
+union sockunion * : lua_decode_sockunion,                       \
+time_t * : lua_decode_timet,                                    \
+char * : lua_decode_stringp,                                    \
+struct attr * : lua_decode_attr,                                \
+struct peer * : lua_decode_noop,                                \
+const struct prefix * : lua_decode_noop,                        \
+const struct ipaddr * : lua_decode_noop,                        \
+const struct ethaddr * : lua_decode_noop,                       \
+const struct nexthop_group * : lua_decode_noop,                 \
+const struct nexthop * : lua_decode_noop,                       \
+struct zebra_dplane_ctx * : lua_decode_noop                     \
+)((L), -1, (value))
+
+/*
+ * Call Lua function state (abstraction for a single Lua function)
+ *
+ * lfs
+ *    The Lua function to call; this should have been loaded in by
+ *    frrscript_load(). nargs Number of arguments the function accepts
+ *
+ * Returns:
+ *    0 if the script ran successfully, nonzero otherwise.
+ */
+int _frrscript_call_lua(struct lua_function_state *lfs, int nargs);
+
+/*
+ * Wrapper for calling Lua function state.
+ *
+ * The Lua function name (f) to run should have already been checked by
+ * frrscript_load. So this wrapper will:
+ * 1) Find the Lua function state, which contains the Lua state
+ * 2) Clear the Lua state (there may be leftovers items from previous call)
+ * 3) Push the Lua function (f)
+ * 4) Map frrscript_call arguments onto their encoder and decoders, push those
+ * 5) Call _frrscript_call_lua (Lua execution takes place)
+ * 6) Write back to frrscript_call arguments using their decoders
+ *
+ * This wrapper can be called multiple times (after one frrscript_load).
+ *
+ * fs
+ *    The struct frrscript in which the Lua fuction was loaded into
+ * f
+ *    Name of the Lua function.
+ *
+ * Returns:
+ *    0 if the script ran successfully, nonzero otherwise.
+ */
+#define frrscript_call(fs, f, ...)                                                                                                                                 \
+	({                                                                                                                                                         \
+		struct lua_function_state lookup = {.name = (f)};                                                                                                  \
+		struct lua_function_state *lfs;                                                                                                                    \
+		lfs = hash_lookup((fs)->lua_function_hash, &lookup);                                                                                               \
+		lfs == NULL ? ({                                                                                                                                   \
+			zlog_err(                                                                                                                                  \
+				"frrscript: '%s.lua': '%s': tried to call this function but it was not loaded",                                                    \
+				(fs)->name, (f));                                                                                                                  \
+			1;                                                                                                                                         \
+		})                                                                                                                                                 \
+			    : ({                                                                                                                                   \
+				      lua_settop(lfs->L, 0);                                                                                                       \
+				      lua_getglobal(lfs->L, f);                                                                                                    \
+				      MAP_LISTS(ENCODE_ARGS, ##__VA_ARGS__);                                                                                       \
+				      _frrscript_call_lua(                                                                                                         \
+					      lfs, PP_NARG(__VA_ARGS__));                                                                                          \
+			      }) != 0                                                                                                                              \
+				      ? ({                                                                                                                         \
+						zlog_err(                                                                                                          \
+							"frrscript: '%s.lua': '%s': this function called but returned non-zero exit code. No variables modified.", \
+							(fs)->name, (f));                                                                                          \
+						1;                                                                                                                 \
+					})                                                                                                                         \
+				      : ({                                                                                                                         \
+						MAP_LISTS(DECODE_ARGS,                                                                                             \
+							  ##__VA_ARGS__);                                                                                          \
+						0;                                                                                                                 \
+					});                                                                                                                        \
+	})
+
+/*
+ * Get result from finished function
+ *
+ * fs
+ *    The script. This script must have been run already.
+ * function_name
+ *    Name of the Lua function.
+ * name
+ *    Name of the result.
+ *    This will be used as a string key to retrieve from the table that the
+ *    Lua function returns.
+ *    The name here should *not* appear in frrscript_call.
+ * lua_to
+ *    Function pointer to a lua_to decoder function.
+ *    This function should allocate and decode a value from the Lua state.
+ *
+ * Returns:
+ *    A pointer to the decoded value from the Lua state, or NULL if no such
+ *    value.
+ */
+void *frrscript_get_result(struct frrscript *fs, const char *function_name,
+			   const char *name,
+			   void *(*lua_to)(lua_State *L, int idx));
+
+#ifdef __cplusplus
+}
+#endif /* __cplusplus */
+
+#endif /* HAVE_SCRIPTING */
+
+#endif /* __FRRSCRIPT_H__ */