1 files changed, 74 insertions, 0 deletions
diff --git a/bgpd/bgp_regex.c b/bgpd/bgp_regex.c
new file mode 100644
index 0000000..68137a5
--- /dev/null
+++ b/bgpd/bgp_regex.c
@@ -0,0 +1,74 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* AS regular expression routine
+ * Copyright (C) 1999 Kunihiro Ishiguro
+ */
+
+#include <zebra.h>
+
+#include "log.h"
+#include "command.h"
+#include "memory.h"
+#include "queue.h"
+#include "filter.h"
+
+#include "bgpd.h"
+#include "bgp_aspath.h"
+#include "bgp_regex.h"
+
+/* Character `_' has special mean.  It represents [,{}() ] and the
+   beginning of the line(^) and the end of the line ($).
+
+   (^|[,{}() ]|$) */
+
+regex_t *bgp_regcomp(const char *regstr)
+{
+	/* Convert _ character to generic regular expression. */
+	int i, j;
+	int len;
+	int magic = 0;
+	char *magic_str;
+	char magic_regexp[] = "(^|[,{}() ]|$)";
+	int ret;
+	regex_t *regex;
+
+	len = strlen(regstr);
+	for (i = 0; i < len; i++)
+		if (regstr[i] == '_')
+			magic++;
+
+	magic_str = XMALLOC(MTYPE_TMP, len + (14 * magic) + 1);
+
+	for (i = 0, j = 0; i < len; i++) {
+		if (regstr[i] == '_') {
+			memcpy(magic_str + j, magic_regexp,
+			       strlen(magic_regexp));
+			j += strlen(magic_regexp);
+		} else
+			magic_str[j++] = regstr[i];
+	}
+	magic_str[j] = '\0';
+
+	regex = XMALLOC(MTYPE_BGP_REGEXP, sizeof(regex_t));
+
+	ret = regcomp(regex, magic_str, REG_EXTENDED | REG_NOSUB);
+
+	XFREE(MTYPE_TMP, magic_str);
+
+	if (ret != 0) {
+		XFREE(MTYPE_BGP_REGEXP, regex);
+		return NULL;
+	}
+
+	return regex;
+}
+
+int bgp_regexec(regex_t *regex, struct aspath *aspath)
+{
+	return regexec(regex, aspath->str, 0, NULL, 0);
+}
+
+void bgp_regex_free(regex_t *regex)
+{
+	regfree(regex);
+	XFREE(MTYPE_BGP_REGEXP, regex);
+}