Added some initial support for a userspace server to receive requests.

1 files changed, 210 insertions, 0 deletions

diff --git a/userspace/ncr-server/ncr-server.c b/userspace/ncr-server/ncr-server.c
new file mode 100644
index 0000000..3b3c72a
--- /dev/null
+++ b/userspace/ncr-server/ncr-server.c
@@ -0,0 +1,210 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <netlink/netlink.h>
+#include <netlink/socket.h>
+#include <netlink/genl/genl.h>
+#include <netlink/genl/ctrl.h>
+#include "../ncr-storage-low.h"
+#include "ncr-server.h"
+#include <list.h>
+
+static int _notify_listening(struct nl_sock * sock);
+
+static struct nla_policy def_policy[ATTR_MAX+1] =
+{
+     [ATTR_STRUCT_STORE] = { .type = NLA_UNSPEC,
+                          .minlen = sizeof(struct storage_item_st) },
+     [ATTR_STRUCT_LOAD] = { .type = NLA_UNSPEC,
+                          .minlen = sizeof(struct ncr_gnl_load_cmd_st) },
+};
+
+static struct actions {
+	list_head list;
+	int cmd; /* CMD_* */
+	union {
+		struct storage_item_st tostore;
+		struct ncr_gnl_load_cmd_st toload;
+	} data;
+} todo;
+
+static int add_store_cmd(struct storage_item_st* tostore)
+{
+	struct actions* item;
+
+	item = malloc(sizeof(*item));
+	if (item == NULL) {
+		err();
+		return -ERR_MEM;
+	}
+	item->cmd = CMD_STORE;
+	memcpy(item->data.tostore, tostore, sizeof(item->data.tostore));
+
+	list_add(item, &todo.list);
+	return 0;
+}
+
+static int add_load_cmd(struct ncr_gnl_load_cmd_st* toload)
+{
+	struct actions* item;
+
+	item = malloc(sizeof(*item));
+	if (item == NULL) {
+		err();
+		return -ERR_MEM;
+	}
+	item->cmd = CMD_LOAD;
+	memcpy(item->data.toload, toload, sizeof(item->data.toload));
+
+	list_add(item, &todo.list);
+	return 0;
+}
+
+static int msg_cb(struct nl_msg *msg, void *arg)
+{
+	struct nlmsghdr *nlh = nlmsg_hdr(msg);
+	struct nlattr *attrs[ATTR_MAX+1];
+
+		// Validate message and parse attributes
+	genlmsg_parse(nlh, 0, attrs, ATTR_MAX, def_policy);
+
+	if (attrs[ATTR_STRUCT_STORE]) {
+		struct storage_item_st *item = nla_get(attrs[ATTR_STRUCT_STORE]);
+		fprintf(stderr, "asked to store: %s\n", item->label);
+
+		add_store_cmd(item);
+	}
+
+	if (attrs[ATTR_STRUCT_LOAD]) {
+		struct ncr_gnl_load_cmd_st *load = nla_get(attrs[ATTR_STRUCT_LOAD]);
+		fprintf(stderr, "asked to load: %s\n", load->label);
+
+		add_load_cmd(item);
+	}
+
+	return NL_STOP;
+}
+
+
+int main()
+{
+struct nl_sock *sock;
+int ret;
+
+	memset(&todo, 0, sizeof(todo));
+	LIST_HEAD_INIT(&todo.list);
+
+	// Allocate a new netlink socket
+	sock = nl_socket_alloc();
+	if (sock == NULL) {
+		err();
+		return ERR_CONNECT;
+	}
+
+	// Connect to generic netlink socket on kernel side
+	ret = genl_connect(sock);
+	if (ret < 0) {
+		err();
+		return ERR_CONNECT;
+	}
+	
+	// Ask kernel to resolve family name to family id
+	family = genl_ctrl_resolve(sock, NCR_NL_STORAGE_NAME);
+	if (family < 0) {
+		err();
+		return ERR_CONNECT;
+	}
+
+	/* set our callback to receive messages */
+	ret = nl_socket_modify_cb(sock, NL_CB_VALID, NL_CB_CUSTOM, msg_cb, NULL);
+	if (ret < 0) {
+		fprintf(stderr, "Could not set listening callback.\n");
+		exit(1);
+	}
+
+	ret = _notify_listening(sock);
+	if (ret < 0) {
+		fprintf(stderr, "Could not notify kernel subsystem.\n");
+		exit(1);
+	}
+
+	// Wait for the answer and receive it
+	do {
+		ret = nl_recvmsgs_default(sock);
+
+		/* we have to consume the todo list */
+		if (ret == 0) {
+			//store_if_needed(sock);
+			//load_if_needed(sock);
+		}
+	} while (ret == 0);
+	fprintf(stderr, "received: %d\n", ret);
+
+}
+
+static int _notify_listening(struct nl_sock * sock)
+{
+struct nl_msg *msg;
+int family, ret;
+
+	// Construct a generic netlink by allocating a new message, fill in
+	// the header and append a simple integer attribute.
+	msg = nlmsg_alloc();
+	if (msg == NULL) {
+		err();
+		return ERR_MEM;
+	}
+
+	genlmsg_put(msg, NL_AUTO_PID, NL_AUTO_SEQ, family, 0, NLM_F_REQUEST,
+	 CMD_LISTENING, NCR_NL_STORAGE_VERSION);
+
+	// Send message over netlink socket
+	ret = nl_send_auto_complete(sock, msg);
+	nlmsg_free(msg);
+
+	if (ret < 0) {
+		err();
+		return ERR_CONNECT;
+	}
+
+	return 0;
+}
+
+
+static int send_store_ack(struct nl_sock * sock, uint8_t val)
+{
+struct nl_msg *msg;
+int family, ret;
+
+	// Construct a generic netlink by allocating a new message, fill in
+	// the header and append a simple integer attribute.
+	msg = nlmsg_alloc();
+	if (msg == NULL) {
+		err();
+		return ERR_MEM;
+	}
+
+	genlmsg_put(msg, NL_AUTO_PID, NL_AUTO_SEQ, family, 0, NLM_F_REQUEST,
+	 CMD_STORE_ACK, NCR_NL_STORAGE_VERSION);
+
+	ret = nla_put_u8(msg, ATTR_STORE_ACK, val);
+	if (ret < 0) {
+		err();
+		ret = ERR_SEND;
+		goto fail;
+	}
+
+	// Send message over netlink socket
+	ret = nl_send_auto_complete(sock, msg);
+	nlmsg_free(msg);
+
+	if (ret < 0) {
+		err();
+		return ERR_SEND;
+	}
+
+	return 0;
+fail:
+	nlmsg_free(msg);
+	return ret;
+}