1 files changed, 168 insertions, 0 deletions
diff --git a/lib/route/pktloc.c b/lib/route/pktloc.c
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--- /dev/null
+++ b/lib/route/pktloc.c
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+/*
+ * lib/route/pktloc.c     Packet Location Aliasing
+ *
+ *	This library 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 version 2 of the License.
+ *
+ * Copyright (c) 2008-2010 Thomas Graf <tgraf@suug.ch>
+ */
+
+/**
+ * @ingroup tc
+ * @defgroup pktloc Packet Location Aliasing
+ * Packet Location Aliasing
+ *
+ * The packet location aliasing interface eases the use of offset definitions
+ * inside packets by allowing them to be referenced by name. Known positions
+ * of protocol fields are stored in a configuration file and associated with
+ * a name for later reference. The configuration file is distributed with the
+ * library and provides a well defined set of definitions for most common
+ * protocol fields.
+ *
+ * @subsection pktloc_examples Examples
+ * @par Example 1.1 Looking up a packet location
+ * @code
+ * struct rtnl_pktloc *loc;
+ *
+ * rtnl_pktloc_lookup("ip.src", &loc);
+ * @endcode
+ * @{
+ */
+
+#include <netlink-local.h>
+#include <netlink-tc.h>
+#include <netlink/netlink.h>
+#include <netlink/utils.h>
+#include <netlink/route/pktloc.h>
+
+#include "pktloc_syntax.h"
+#include "pktloc_grammar.h"
+
+/** @cond */
+#define PKTLOC_NAME_HT_SIZ 256
+
+static struct nl_list_head pktloc_name_ht[PKTLOC_NAME_HT_SIZ];
+
+/* djb2 */
+unsigned int pktloc_hash(const char *str)
+{
+	unsigned long hash = 5381;
+	int c;
+
+	while ((c = *str++))
+		hash = ((hash << 5) + hash) + c; /* hash * 33 + c */
+
+	return hash % PKTLOC_NAME_HT_SIZ;
+}
+
+
+void rtnl_pktloc_add(struct rtnl_pktloc *loc)
+{
+	nl_list_add_tail(&loc->list, &pktloc_name_ht[pktloc_hash(loc->name)]);
+}
+
+extern int pktloc_parse(void *scanner);
+
+/** @endcond */
+
+static void rtnl_pktloc_free(struct rtnl_pktloc *loc)
+{
+	if (!loc)
+		return;
+
+	free(loc->name);
+	free(loc);
+}
+
+static int read_pktlocs(void)
+{
+	YY_BUFFER_STATE buf;
+	yyscan_t scanner = NULL;
+	static time_t last_read;
+	struct stat st = {0};
+	char *path;
+	int i, err;
+	FILE *fd;
+
+	asprintf(&path, "%s/pktloc", SYSCONFDIR);
+
+	/* if stat fails, just try to read the file */
+	if (stat(path, &st) == 0) {
+		/* Don't re-read file if file is unchanged */
+		if (last_read == st.st_mtime)
+			return 0;
+	}
+
+	if (!(fd = fopen(path, "r")))
+		return -NLE_PKTLOC_FILE;
+
+	for (i = 0; i < PKTLOC_NAME_HT_SIZ; i++) {
+		struct rtnl_pktloc *loc, *n;
+
+		nl_list_for_each_entry_safe(loc, n, &pktloc_name_ht[i], list)
+			rtnl_pktloc_free(loc);
+
+		nl_init_list_head(&pktloc_name_ht[i]);
+	}
+
+	if ((err = pktloc_lex_init(&scanner)) < 0)
+		return -NLE_FAILURE;
+
+	buf = pktloc__create_buffer(fd, YY_BUF_SIZE, scanner);
+	pktloc__switch_to_buffer(buf, scanner);
+
+	if ((err = pktloc_parse(scanner)) < 0)
+		return -NLE_FAILURE;
+
+	if (scanner)
+		pktloc_lex_destroy(scanner);
+
+	free(path);
+	last_read = st.st_mtime;
+
+	return 0;
+}
+
+/**
+ * Lookup packet location alias
+ * @arg name		Name of packet location.
+ *
+ * Tries to find a matching packet location alias for the supplied
+ * packet location name.
+ *
+ * The file containing the packet location definitions is automatically
+ * re-read if its modification time has changed since the last call.
+ *
+ * @return 0 on success or a negative error code.
+ * @retval NLE_PKTLOC_FILE Unable to open packet location file.
+ * @retval NLE_OBJ_NOTFOUND No matching packet location alias found.
+ */
+int rtnl_pktloc_lookup(const char *name, struct rtnl_pktloc **result)
+{
+	struct rtnl_pktloc *loc;
+	int hash, err;
+
+	if ((err = read_pktlocs()) < 0)
+		return err;
+
+	hash = pktloc_hash(name);
+	nl_list_for_each_entry(loc, &pktloc_name_ht[hash], list) {
+		if (!strcasecmp(loc->name, name)) {
+			*result = loc;
+			return 0;
+		}
+	}
+
+	return -NLE_OBJ_NOTFOUND;
+}
+
+static int __init pktloc_init(void)
+{
+	int i;
+
+	for (i = 0; i < PKTLOC_NAME_HT_SIZ; i++)
+		nl_init_list_head(&pktloc_name_ht[i]);
+	
+	return 0;
+}