This patch adds a generic netlink controller interface.
The controller is the only module using this at the moment.
Thomas has a sample user of genetlink that would fit here; bug him
for it.

Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
diff --git a/genl/genl.c b/genl/genl.c
new file mode 100644
index 0000000..3ae75ae
--- /dev/null
+++ b/genl/genl.c
@@ -0,0 +1,162 @@
+/*
+ * genl.c		"genl" utility frontend.
+ *
+ *		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.
+ *
+ * Authors:	Jamal Hadi Salim
+ *
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <syslog.h>
+#include <fcntl.h>
+#include <dlfcn.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+#include <string.h>
+#include <errno.h>
+#include <linux/netlink.h>
+#include <linux/rtnetlink.h> /* until we put our own header */
+#include "SNAPSHOT.h"
+#include "utils.h"
+#include "genl_utils.h"
+
+int show_stats = 0;
+int show_details = 0;
+int show_raw = 0;
+int resolve_hosts = 0;
+
+static void *BODY;
+static struct genl_util * genl_list;
+
+
+static int print_nofopt(const struct sockaddr_nl *who, struct nlmsghdr *n,
+			void *arg)
+{
+	fprintf((FILE *) arg, "unknown genl type ..\n");
+	return 0;
+}
+
+static int parse_nofopt(struct genl_util *f, int argc, char **argv)
+{
+	if (argc) {
+		fprintf(stderr, "Unknown genl \"%s\", hence option \"%s\" "
+			"is unparsable\n", f->name, *argv);
+		return -1;
+	}
+
+	return 0;
+}
+
+static struct genl_util *get_genl_kind(char *str)
+{
+	void *dlh;
+	char buf[256];
+	struct genl_util *f;
+
+	for (f = genl_list; f; f = f->next)
+		if (strcmp(f->name, str) == 0)
+			return f;
+
+	snprintf(buf, sizeof(buf), "%s.so", str);
+	dlh = dlopen(buf, RTLD_LAZY);
+	if (dlh == NULL) {
+		dlh = BODY;
+		if (dlh == NULL) {
+			dlh = BODY = dlopen(NULL, RTLD_LAZY);
+			if (dlh == NULL)
+				goto noexist;
+		}
+	}
+
+	snprintf(buf, sizeof(buf), "%s_genl_util", str);
+
+	f = dlsym(dlh, buf);
+	if (f == NULL)
+		goto noexist;
+reg:
+	f->next = genl_list;
+	genl_list = f;
+	return f;
+
+noexist:
+	f = malloc(sizeof(*f));
+	if (f) {
+		memset(f, 0, sizeof(*f));
+		strncpy(f->name, str, 15);
+		f->parse_genlopt = parse_nofopt;
+		f->print_genlopt = print_nofopt;
+		goto reg;
+	}
+	return f;
+}
+
+static void usage(void) __attribute__((noreturn));
+
+static void usage(void)
+{
+	fprintf(stderr, "Usage: genl [ OPTIONS ] OBJECT | help }\n"
+	                "where  OBJECT := { ctrl etc }\n"
+	                "       OPTIONS := { -s[tatistics] | -d[etails] | -r[aw] }\n");
+	exit(-1);
+}
+
+int main(int argc, char **argv)
+{
+	char *basename;
+
+	basename = strrchr(argv[0], '/');
+	if (basename == NULL)
+		basename = argv[0];
+	else
+		basename++;
+
+	while (argc > 1) {
+		if (argv[1][0] != '-')
+			break;
+		if (matches(argv[1], "-stats") == 0 ||
+		    matches(argv[1], "-statistics") == 0) {
+			++show_stats;
+		} else if (matches(argv[1], "-details") == 0) {
+			++show_details;
+		} else if (matches(argv[1], "-raw") == 0) {
+			++show_raw;
+		} else if (matches(argv[1], "-Version") == 0) {
+			printf("genl utility, iproute2-ss%s\n", SNAPSHOT);
+			exit(0);
+		} else if (matches(argv[1], "-help") == 0) {
+			usage();
+		} else {
+			fprintf(stderr, "Option \"%s\" is unknown, try "
+				"\"genl -help\".\n", argv[1]);
+			exit(-1);
+		}
+		argc--;	argv++;
+	}
+
+	if (argc > 1) {
+		int ret;
+		struct genl_util *a = NULL;
+		a = get_genl_kind(argv[1]);
+		if (NULL == a) {
+			fprintf(stderr,"bad genl %s\n",argv[1]);
+		}
+
+		ret = a->parse_genlopt(a, argc-1, argv+1);
+		return ret;
+
+		if (matches(argv[1], "help") == 0)
+			usage();
+		fprintf(stderr, "Object \"%s\" is unknown, try \"genl "
+			"-help\".\n", argv[1]);
+		exit(-1);
+	}
+
+	usage();
+}