lib: new defaults logic

Since we've been writing out "frr version" and "frr defaults" for about
a year and a half now, we can now actually use them to manage defaults.

Signed-off-by: David Lamparter <equinox@diac24.net>

Makefile.am

@@ -228,8 +228,6 @@ EXTRA_DIST += \
 	vrrpd/Makefile \
 	# end
 
-noinst_HEADERS += defaults.h
-
 clean-local: clean-python
 .PHONY: clean-python
 clean-python:

lib/command.c

@@ -1575,18 +1575,6 @@ DEFUN (show_version,
 	return CMD_SUCCESS;
 }
 
-/* "Set" version ... ignore version tags */
-DEFUN (frr_version_defaults,
-       frr_version_defaults_cmd,
-       "frr <version|defaults> LINE...",
-       "FRRouting global parameters\n"
-       "version configuration was written by\n"
-       "set of configuration defaults used\n"
-       "version string\n")
-{
-	return CMD_SUCCESS;
-}
-
 /* Help display function for all node. */
 DEFUN (config_help,
        config_help_cmd,
@@ -1721,8 +1709,10 @@ static int vty_write_config(struct vty *vty)
 		vty_out(vty, "!\n");
 	}
 
+	if (strcmp(frr_defaults_version(), FRR_VER_SHORT))
+		vty_out(vty, "! loaded from %s\n", frr_defaults_version());
 	vty_out(vty, "frr version %s\n", FRR_VER_SHORT);
-	vty_out(vty, "frr defaults %s\n", DFLT_NAME);
+	vty_out(vty, "frr defaults %s\n", frr_defaults_profile());
 	vty_out(vty, "!\n");
 
 	for (i = 0; i < vector_active(cmdvec); i++)
@@ -2941,7 +2931,6 @@ void cmd_init(int terminal)
 	install_element(CONFIG_NODE, &no_hostname_cmd);
 	install_element(CONFIG_NODE, &domainname_cmd);
 	install_element(CONFIG_NODE, &no_domainname_cmd);
-	install_element(CONFIG_NODE, &frr_version_defaults_cmd);
 
 	if (terminal > 0) {
 		install_element(CONFIG_NODE, &debug_memstats_cmd);

lib/defaults.c

@@ -18,9 +18,20 @@
 #include <zebra.h>
 
 #include "defaults.h"
-#include "libfrr.h"
 #include "version.h"
 
+static char df_version[128] = FRR_VER_SHORT, df_profile[128] = DFLT_NAME;
+static struct frr_default *dflt_first = NULL, **dflt_next = &dflt_first;
+
+/* these are global for all FRR daemons.  they have to be, since we write an
+ * integrated config with the same value for all daemons.
+ */
+const char *frr_defaults_profiles[] = {
+	"traditional",
+	"datacenter",
+	NULL,
+};
+
 static int version_value(int ch)
 {
 	/* non-ASCII shouldn't happen */
@@ -73,3 +84,142 @@ int frr_version_cmp(const char *aa, const char *bb)
 	}
 	return 0;
 }
+
+static void frr_default_apply_one(struct frr_default *dflt, bool check);
+
+void frr_default_add(struct frr_default *dflt)
+{
+	dflt->next = NULL;
+	*dflt_next = dflt;
+	dflt_next = &dflt->next;
+
+	frr_default_apply_one(dflt, true);
+}
+
+static bool frr_match_version(const char *name, const char *vspec,
+			      const char *version, bool check)
+{
+	int cmp;
+	static struct spec {
+		const char *str;
+		bool dir, eq;
+	} *s, specs[] = {
+		{"<=", -1, 1},
+		{">=", 1, 1},
+		{"==", 0, 1},
+		{"<", -1, 0},
+		{">", 1, 0},
+		{"=", 0, 1},
+		{NULL, 0, 0},
+	};
+
+	if (!vspec)
+		/* NULL = all versions */
+		return true;
+
+	for (s = specs; s->str; s++)
+		if (!strncmp(s->str, vspec, strlen(s->str)))
+			break;
+	if (!s->str) {
+		if (check)
+			fprintf(stderr, "invalid version specifier for %s: %s",
+				name, vspec);
+		/* invalid version spec, never matches */
+		return false;
+	}
+
+	vspec += strlen(s->str);
+	while (isspace((unsigned char)*vspec))
+		vspec++;
+
+	cmp = frr_version_cmp(version, vspec);
+	if (cmp == s->dir || (s->eq && cmp == 0))
+		return true;
+
+	return false;
+}
+
+static void frr_default_apply_one(struct frr_default *dflt, bool check)
+{
+	struct frr_default_entry *entry = dflt->entries;
+	struct frr_default_entry *dfltentry = NULL, *saveentry = NULL;
+
+	for (; entry->match_version || entry->match_profile; entry++) {
+		if (entry->match_profile
+			&& strcmp(entry->match_profile, df_profile))
+			continue;
+
+		if (!dfltentry && frr_match_version(dflt->name,
+				entry->match_version, df_version, check))
+			dfltentry = entry;
+		if (!saveentry && frr_match_version(dflt->name,
+				entry->match_version, FRR_VER_SHORT, check))
+			saveentry = entry;
+
+		if (dfltentry && saveentry && !check)
+			break;
+	}
+	/* found default or arrived at last entry that has NULL,NULL spec */
+
+	if (!dfltentry)
+		dfltentry = entry;
+	if (!saveentry)
+		saveentry = entry;
+
+	if (dflt->dflt_str)
+		*dflt->dflt_str = dfltentry->val_str;
+	if (dflt->dflt_long)
+		*dflt->dflt_long = dfltentry->val_long;
+	if (dflt->dflt_ulong)
+		*dflt->dflt_ulong = dfltentry->val_ulong;
+	if (dflt->dflt_float)
+		*dflt->dflt_float = dfltentry->val_float;
+	if (dflt->save_str)
+		*dflt->save_str = saveentry->val_str;
+	if (dflt->save_long)
+		*dflt->save_long = saveentry->val_long;
+	if (dflt->save_ulong)
+		*dflt->save_ulong = saveentry->val_ulong;
+	if (dflt->save_float)
+		*dflt->save_float = saveentry->val_float;
+}
+
+void frr_defaults_apply(void)
+{
+	struct frr_default *dflt;
+
+	for (dflt = dflt_first; dflt; dflt = dflt->next)
+		frr_default_apply_one(dflt, false);
+}
+
+bool frr_defaults_profile_valid(const char *profile)
+{
+	const char **p;
+
+	for (p = frr_defaults_profiles; *p; p++)
+		if (!strcmp(profile, *p))
+			return true;
+	return false;
+}
+
+const char *frr_defaults_version(void)
+{
+	return df_version;
+}
+
+const char *frr_defaults_profile(void)
+{
+	return df_profile;
+}
+
+void frr_defaults_version_set(const char *version)
+{
+	strlcpy(df_version, version, sizeof(df_version));
+	frr_defaults_apply();
+}
+
+void frr_defaults_profile_set(const char *profile)
+{
+	strlcpy(df_profile, profile, sizeof(df_profile));
+	frr_defaults_apply();
+}