lib: Provide first implementation of revised CDAP

This commit introduces a first version of the revised CDAP
specification. CACEP (for authentication purposes) has been separated
from CDAP. Application developers may use CDAP if they find it
useful. Within Ouroboros CDAP will be used to perform operations on
the RIB of an IPCP.

19 files changed, 586 insertions, 174 deletions

diff --git a/include/ouroboros/CMakeLists.txt b/include/ouroboros/CMakeLists.txt
index 68c88a18..ee339294 100644
--- a/include/ouroboros/CMakeLists.txt
+++ b/include/ouroboros/CMakeLists.txt
@@ -3,14 +3,14 @@ configure_file(
   "${CMAKE_CURRENT_BINARY_DIR}/config.h")
 
 set(HEADER_FILES
-        cdap.h
-        dev.h
-        errno.h
-        flow.h
-        irm.h
-        irm_config.h
-        nsm.h
-        qos.h
-)
+  cdap.h
+  common.h
+  dev.h
+  errno.h
+  flow.h
+  irm.h
+  irm_config.h
+  nsm.h
+  qos.h)
 
 install(FILES ${HEADER_FILES} DESTINATION usr/include/ouroboros)
diff --git a/include/ouroboros/cdap.h b/include/ouroboros/cdap.h
index 72788ad6..da669feb 100644
--- a/include/ouroboros/cdap.h
+++ b/include/ouroboros/cdap.h
@@ -4,6 +4,7 @@
  * The Common Distributed Application Protocol
  *
  *    Sander Vrijders <[email protected]>
+ *    Dimitri Staessens <[email protected]>
  *
  * 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
@@ -23,148 +24,75 @@
 #ifndef OUROBOROS_CDAP_H
 #define OUROBOROS_CDAP_H
 
+#include <ouroboros/common.h>
+
 #include <stdbool.h>
+#include <stdint.h>
+#include <unistd.h>
+
+#define F_SYNC 0x0001
 
 struct cdap;
 
+/* Callback functions that work on the application's RIB */
 struct cdap_ops {
-        /* Sender related callbacks */
-        int (* handle_connect_r)(int fd,
-                                 int invoke_id,
-                                 int result);
-        int (* handle_release_r)(int fd,
-                                 int invoke_id,
-                                 int result);
-        int (* handle_read_r)(int fd,
-                              int invoke_id,
-                              int result,
-                              char * reason,
-                              char * obj_val,
-                              bool complete);
-        int (* handle_cancelread_r)(int fd,
-                                    int invoke_id,
-                                    int result);
-        int (* handle_write_r)(int fd,
-                               int invoke_id,
-                               int result,
-                               char * reason,
-                               char * obj_val);
-        int (* handle_create_r)(int fd,
-                                int invoke_id,
-                                int result);
-        int (* handle_delete_r)(int fd,
-                                int invoke_id,
-                                int result);
-        int (* handle_start_r)(int fd,
-                               int invoke_id,
-                               int result);
-        int (* handle_stop_r)(int fd,
-                              int invoke_id,
-                              int result);
+        int (* cdap_reply)(struct cdap * instance,
+                           int           invoke_id,
+                           int           result,
+                           buffer_t *    val,
+                           size_t        len);
+
+        int (* cdap_read)(struct cdap * instance,
+                          char *        name);
+        int (* cdap_write)(struct cdap * instance,
+                           char *        name,
+                           buffer_t *    val,
+                           size_t        len,
+                           uint32_t      flags);
 
-        /* Receiver related callbacks */
-        int (* handle_connect)(int fd,
-                               int invoke_id,
-                               rina_name_t src,
-                               rina_name_t dst,
-                               char * auth_mech,
-                               char * auth_val);
-        int (* handle_release)(int fd,
-                               int invoke_id);
-        int (* handle_cancelread)(int fd,
-                                  int invoke_id);
-        int (* handle_write)(int fd,
-                             int invoke_id,
-                             char * obj_name,
-                             char * obj_val);
-        int (* handle_create)(int fd,
-                              int invoke_id,
-                              char * obj_class,
-                              char * obj_name,
-                              char * obj_val);
-        int (* handle_delete)(int fd,
-                              int invoke_id,
-                              char * obj_name);
-        int (* handle_start)(int fd,
-                             int invoke_id,
-                             char * obj_name,
-                             char * obj_val);
-        int (* handle_stop)(int fd,
-                            int invoke_id,
-                            char * obj_name,
-                            char * obj_val);
+        int (* cdap_create)(struct cdap * instance,
+                            char *        name,
+                            buffer_t      val);
+        int (* cdap_delete)(struct cdap * instance,
+                            char *        name,
+                            buffer_t      val);
+
+        int (* cdap_start)(struct cdap * instance,
+                           char *        name);
+        int (* cdap_stop)(struct cdap * instance,
+                          char *        name);
 };
 
-struct cdap * cdap_create(struct cdap_ops ops,
-                          int fd);
+/* Assumes flow is blocking */
+struct cdap * cdap_create(struct cdap_ops * ops,
+                          int               fd);
 int           cdap_destroy(struct cdap * instance);
 
-/* Sender related functions */
-int           cdap_send_connect(struct cdap * instance,
-                                int invoke_id,
-                                rina_name_t src,
-                                rina_name_t dst,
-                                char * auth_mech,
-                                char * auth_val);
-int           cdap_send_release(struct cdap * instance,
-                                int invoke_id);
+/* Returns a positive invoke-id on success to be used in the callback */
 int           cdap_send_read(struct cdap * instance,
-                             int invoke_id,
-                             char * obj_name);
-int           cdap_send_cancelread(struct cdap * instance,
-                                   int invoke_id,
-                                   char * obj_name);
+                             char *        name);
 int           cdap_send_write(struct cdap * instance,
-                              int invoke_id,
-                              char * obj_name,
-                              char * obj_val);
+                              char *        name,
+                              buffer_t *    val,
+                              size_t        len,
+                              uint32_t      flags);
+
 int           cdap_send_create(struct cdap * instance,
-                               int invoke_id,
-                               char * obj_name,
-                               char * obj_val);
+                               char *        name,
+                               buffer_t      val);
 int           cdap_send_delete(struct cdap * instance,
-                               int invoke_id,
-                               char * obj_name);
+                               char *        name,
+                               buffer_t      val);
+
 int           cdap_send_start(struct cdap * instance,
-                              int invoke_id,
-                              char * obj_name,
-                              char * obj_val);
+                              char *        name);
 int           cdap_send_stop(struct cdap * instance,
-                             int invoke_id,
-                             char * obj_name,
-                             char * obj_val);
+                             char *        name);
 
-/* Receiver related functions */
-int           cdap_send_connect_r(struct cdap * instance,
-                                  int invoke_id,
-                                  int result);
-int           cdap_send_release_r(struct cdap * instance,
-                                  int invoke_id,
-                                  int result);
-int           cdap_send_read_r(struct cdap * instance,
-                               int invoke_id,
-                               int result,
-                               char * reason,
-                               char * obj_val,
-                               bool complete);
-int           cdap_send_cancelread_r(struct cdap * instance,
-                                     int invoke_id,
-                                     int result);
-int           cdap_send_write_r(struct cdap * instance,
-                                int invoke_id,
-                                int result,
-                                char * obj_name,
-                                char * obj_val);
-int           cdap_send_create_r(struct cdap * instance,
-                                 int invoke_id,
-                                 int result);
-int           cdap_send_delete_r(struct cdap * instance,
-                                 int invoke_id,
-                                 int result);
-int           cdap_send_start_r(struct cdap * instance,
-                                int invoke_id,
-                                int result);
-int           cdap_send_stop_r(struct cdap * instance,
-                               int invoke_id,
-                               int result);
+/* Can only be called following a callback function */
+int           cdap_send_reply(struct cdap * instance,
+                              int           invoke_id,
+                              int           result,
+                              buffer_t *    val,
+                              size_t        len);
 #endif
diff --git a/include/ouroboros/common.h b/include/ouroboros/common.h
index 039e1a83..dbd050f1 100644
--- a/include/ouroboros/common.h
+++ b/include/ouroboros/common.h
@@ -25,24 +25,10 @@
 
 #include <stdint.h>
 #include <unistd.h>
-#include <stdbool.h>
-#include <errno.h>
 
 typedef struct {
         uint8_t * data;
-        size_t    size;
+        size_t    len;
 } buffer_t;
 
-/* FIXME: To be decided which QoS cubes we support */
-enum qos_cube {
-        QOS_CUBE_BE = 0,
-        QOS_CUBE_VIDEO
-};
-
-enum flow_state {
-        FLOW_NULL = 0,
-        FLOW_PENDING,
-        FLOW_ALLOCATED
-};
-
 #endif /* OUROBOROS_COMMON_H */
diff --git a/include/ouroboros/ipcp.h b/include/ouroboros/ipcp.h
index f5657b64..c1aa452b 100644
--- a/include/ouroboros/ipcp.h
+++ b/include/ouroboros/ipcp.h
@@ -22,7 +22,7 @@
 
 #include <ouroboros/irm_config.h>
 #include <ouroboros/sockets.h>
-#include <ouroboros/common.h>
+#include <ouroboros/shared.h>
 
 #include <sys/types.h>
 
diff --git a/include/ouroboros/shared.h b/include/ouroboros/shared.h
new file mode 100644
index 00000000..f5e34dc8
--- /dev/null
+++ b/include/ouroboros/shared.h
@@ -0,0 +1,38 @@
+/*
+ * Ouroboros - Copyright (C) 2016
+ *
+ * Shared definitions between IRMd and IPCPs
+ *
+ *    Sander Vrijders <[email protected]>
+ *
+ * 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.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#ifndef OUROBOROS_SHARED_H
+#define OUROBOROS_SHARED_H
+
+/* FIXME: To be decided which QoS cubes we support */
+enum qos_cube {
+        QOS_CUBE_BE = 0,
+        QOS_CUBE_VIDEO
+};
+
+enum flow_state {
+        FLOW_NULL = 0,
+        FLOW_PENDING,
+        FLOW_ALLOCATED
+};
+
+#endif /* OUROBOROS_SHARED_H */
diff --git a/include/ouroboros/shm_du_map.h b/include/ouroboros/shm_du_map.h
index e8934bae..9d6d7aaf 100644
--- a/include/ouroboros/shm_du_map.h
+++ b/include/ouroboros/shm_du_map.h
@@ -24,7 +24,9 @@
 #ifndef OUROBOROS_SHM_DU_MAP_H
 #define OUROBOROS_SHM_DU_MAP_H
 
-#include "common.h"
+#include <errno.h>
+#include <unistd.h>
+#include <stdint.h>
 #include <sys/types.h>
 #include <pthread.h>
 
diff --git a/src/ipcpd/ipcp-data.h b/src/ipcpd/ipcp-data.h
index ce20730b..1e183dca 100644
--- a/src/ipcpd/ipcp-data.h
+++ b/src/ipcpd/ipcp-data.h
@@ -24,7 +24,7 @@
 #ifndef IPCPD_IPCP_DATA_H
 #define IPCPD_IPCP_DATA_H
 
-#include <ouroboros/common.h>
+#include <ouroboros/shared.h>
 #include <ouroboros/list.h>
 #include <sys/types.h>
 #include <pthread.h>
diff --git a/src/ipcpd/ipcp.c b/src/ipcpd/ipcp.c
index 4acbffa2..579203c2 100644
--- a/src/ipcpd/ipcp.c
+++ b/src/ipcpd/ipcp.c
@@ -236,14 +236,14 @@ void * ipcp_main_loop(void * o)
 
                 ipcp_msg__free_unpacked(msg, NULL);
 
-                buffer.size = ipcp_msg__get_packed_size(&ret_msg);
-                if (buffer.size == 0) {
+                buffer.len = ipcp_msg__get_packed_size(&ret_msg);
+                if (buffer.len == 0) {
                         LOG_ERR("Failed to send reply message");
                         close(lsockfd);
                         continue;
                 }
 
-                buffer.data = malloc(buffer.size);
+                buffer.data = malloc(buffer.len);
                 if (buffer.data == NULL) {
                         close(lsockfd);
                         continue;
@@ -251,7 +251,7 @@ void * ipcp_main_loop(void * o)
 
                 ipcp_msg__pack(&ret_msg, buffer.data);
 
-                if (write(lsockfd, buffer.data, buffer.size) == -1) {
+                if (write(lsockfd, buffer.data, buffer.len) == -1) {
                         free(buffer.data);
                         close(lsockfd);
                         continue;
diff --git a/src/ipcpd/ipcp.h b/src/ipcpd/ipcp.h
index 1e9e9763..27c3cf8e 100644
--- a/src/ipcpd/ipcp.h
+++ b/src/ipcpd/ipcp.h
@@ -24,6 +24,8 @@
 #define IPCPD_IPCP_H
 
 #include <ouroboros/config.h>
+#include <ouroboros/shared.h>
+
 #include <pthread.h>
 
 #include "ipcp-ops.h"
diff --git a/src/ipcpd/local/main.c b/src/ipcpd/local/main.c
index 837cbf8c..4802a161 100644
--- a/src/ipcpd/local/main.c
+++ b/src/ipcpd/local/main.c
@@ -31,7 +31,7 @@
 #include <ouroboros/irm_config.h>
 #include <ouroboros/sockets.h>
 #include <ouroboros/bitmap.h>
-#include <ouroboros/common.h>
+#include <ouroboros/shared.h>
 #include <ouroboros/dev.h>
 
 #define OUROBOROS_PREFIX "ipcpd/local"
diff --git a/src/ipcpd/shim-udp/main.c b/src/ipcpd/shim-udp/main.c
index 68d393af..c22947fa 100644
--- a/src/ipcpd/shim-udp/main.c
+++ b/src/ipcpd/shim-udp/main.c
@@ -340,8 +340,8 @@ static int send_shim_udp_msg(shim_udp_msg_t * msg,
        r_saddr.sin_addr.s_addr = dst_ip_addr;
        r_saddr.sin_port        = LISTEN_PORT;
 
-       buf.size = shim_udp_msg__get_packed_size(msg);
-       if (buf.size == 0) {
+       buf.len = shim_udp_msg__get_packed_size(msg);
+       if (buf.len == 0) {
                return -1;
        }
 
@@ -354,7 +354,7 @@ static int send_shim_udp_msg(shim_udp_msg_t * msg,
 
        if (sendto(shim_data(_ipcp)->s_fd,
                   buf.data,
-                  buf.size,
+                  buf.len,
                   0,
                   (struct sockaddr *) &r_saddr,
                   sizeof(r_saddr)) == -1) {
diff --git a/src/irmd/main.c b/src/irmd/main.c
index 6e3fd74a..0d23ec58 100644
--- a/src/irmd/main.c
+++ b/src/irmd/main.c
@@ -2178,8 +2178,8 @@ void * mainloop()
 
                 pthread_cleanup_pop(true);
 
-                buffer.size = irm_msg__get_packed_size(&ret_msg);
-                if (buffer.size == 0) {
+                buffer.len = irm_msg__get_packed_size(&ret_msg);
+                if (buffer.len == 0) {
                         LOG_ERR("Failed to send reply message.");
                         if (apis != NULL)
                                 free(apis);
@@ -2187,7 +2187,7 @@ void * mainloop()
                         continue;
                 }
 
-                buffer.data = malloc(buffer.size);
+                buffer.data = malloc(buffer.len);
                 if (buffer.data == NULL) {
                         if (apis != NULL)
                                 free(apis);
@@ -2197,7 +2197,7 @@ void * mainloop()
 
                 irm_msg__pack(&ret_msg, buffer.data);
 
-                if (write(cli_sockfd, buffer.data, buffer.size) == -1) {
+                if (write(cli_sockfd, buffer.data, buffer.len) == -1) {
                         free(buffer.data);
                         if (apis != NULL)
                                 free(apis);
diff --git a/src/lib/CMakeLists.txt b/src/lib/CMakeLists.txt
index ae46f5bc..57f44f15 100644
--- a/src/lib/CMakeLists.txt
+++ b/src/lib/CMakeLists.txt
@@ -9,7 +9,9 @@ include_directories(${PROTOBUF_INCLUDE_DIRS})
 protobuf_generate_c(IRM_PROTO_SRCS IRM_PROTO_HDRS irmd_messages.proto)
 protobuf_generate_c(IPCP_PROTO_SRCS IPCP_PROTO_HDRS ipcpd_messages.proto)
 protobuf_generate_c(DIF_CONFIG_PROTO_SRCS DIF_CONFIG_PROTO_HDRS
-                                          dif_config.proto)
+  dif_config.proto)
+protobuf_generate_c(CDAP_PROTO_SRCS CDAP_PROTO_HDRS
+  cdap.proto)
 
 find_library(LIBRT_LIBRARIES rt)
 if(NOT LIBRT_LIBRARIES)
@@ -38,7 +40,8 @@ set(SOURCE_FILES
   )
 
 add_library(ouroboros SHARED ${SOURCE_FILES}
-  ${IRM_PROTO_SRCS} ${IPCP_PROTO_SRCS} ${DIF_CONFIG_PROTO_SRCS})
+  ${IRM_PROTO_SRCS} ${IPCP_PROTO_SRCS}
+  ${DIF_CONFIG_PROTO_SRCS} ${CDAP_PROTO_SRCS})
 
 target_link_libraries(ouroboros ${LIBRT_LIBRARIES}
   ${LIBPTHREAD_LIBRARIES} ${PROTOBUF_C_LIBRARY})
diff --git a/src/lib/cdap.c b/src/lib/cdap.c
index e69de29b..8967c8bd 100644
--- a/src/lib/cdap.c
+++ b/src/lib/cdap.c
@@ -0,0 +1,430 @@
+/*
+ * Ouroboros - Copyright (C) 2016
+ *
+ * The Common Distributed Application Protocol
+ *
+ *    Sander Vrijders <[email protected]>
+ *
+ * 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.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include <ouroboros/cdap.h>
+#include <ouroboros/bitmap.h>
+#include <ouroboros/common.h>
+#include <ouroboros/dev.h>
+
+#include <stdlib.h>
+#include <pthread.h>
+
+#include "cdap.pb-c.h"
+typedef Cdap cdap_t;
+typedef Opcode opcode_t;
+
+#define IDS_SIZE 256
+#define BUF_SIZE 2048
+
+struct cdap {
+        int               fd;
+        struct bmp *      ids;
+        pthread_mutex_t   ids_lock;
+        pthread_t         reader;
+        struct cdap_ops * ops;
+};
+
+
+static ssize_t cdap_msg_to_buffer(cdap_t * msg,
+                                  buffer_t ** val)
+{
+        int i;
+        size_t len;
+
+        len = msg->n_value;
+
+        *val = malloc(len * sizeof(**val));
+        if (*val == NULL) {
+                return -1;
+        }
+
+        for (i = 0; i < len; i++) {
+                if (msg->value[i].data == NULL) {
+                        free(*val);
+                        return -1;
+                }
+
+                (*val)[i].data = msg->value[i].data;
+                (*val)[i].len = msg->value[i].len;
+        }
+
+        return len;
+}
+
+
+static void * sdu_reader(void * o)
+{
+        struct cdap * instance = (struct cdap *) o;
+        cdap_t * msg;
+        uint8_t buf[BUF_SIZE];
+        size_t len;
+        ssize_t length;
+        buffer_t * val;
+
+        while (true) {
+                len = flow_read(instance->fd, buf, BUF_SIZE);
+                if (len < 0) {
+                        return (void *) -1;
+                }
+
+                msg = cdap__unpack(NULL, len, buf);
+                if (msg == NULL) {
+                        continue;
+                }
+
+                switch (msg->opcode) {
+                case OPCODE__READ:
+                        if (msg->name != NULL)
+                                instance->ops->cdap_read(instance,
+                                                         msg->name);
+                        break;
+                case OPCODE__WRITE:
+                        length = cdap_msg_to_buffer(msg, &val);
+                        if (msg->name != NULL &&
+                            msg->value != NULL &&
+                            len > 0) {
+                                instance->ops->cdap_write(instance,
+                                                          msg->name,
+                                                          val,
+                                                          length,
+                                                          msg->flags);
+                                free(val);
+                        }
+                        break;
+                case OPCODE__CREATE:
+                        length = cdap_msg_to_buffer(msg, &val);
+                        if (msg->name != NULL &&
+                            length == 1) {
+                                instance->ops->cdap_create(instance,
+                                                           msg->name,
+                                                           val[0]);
+                                free(val);
+                        }
+                        break;
+                case OPCODE__DELETE:
+                        length = cdap_msg_to_buffer(msg, &val);
+                        if (msg->name != NULL &&
+                            length == 1) {
+                                instance->ops->cdap_create(instance,
+                                                           msg->name,
+                                                           val[0]);
+                                free(val);
+                        }
+                        break;
+                case OPCODE__START:
+                        if (msg->name != NULL)
+                                instance->ops->cdap_start(instance,
+                                                          msg->name);
+                        break;
+                case OPCODE__STOP:
+                        if (msg->name != NULL)
+                                instance->ops->cdap_stop(instance,
+                                                         msg->name);
+                        break;
+                case OPCODE__REPLY:
+                        length = cdap_msg_to_buffer(msg, &val);
+                        if (msg->name != NULL &&
+                            length > 0) {
+                                instance->ops->cdap_reply(instance,
+                                                          msg->invoke_id,
+                                                          msg->result,
+                                                          val,
+                                                          length);
+                                free(val);
+                        }
+                        break;
+                default:
+                        break;
+                }
+
+                cdap__free_unpacked(msg, NULL);
+        }
+
+        return (void *) 0;
+}
+
+struct cdap * cdap_create(struct cdap_ops * ops,
+                          int               fd)
+{
+        struct cdap * instance = NULL;
+
+        if (ops == NULL || fd < 0 ||
+            ops->cdap_reply == NULL ||
+            ops->cdap_read == NULL ||
+            ops->cdap_write == NULL ||
+            ops->cdap_create == NULL ||
+            ops->cdap_delete == NULL ||
+            ops->cdap_start == NULL ||
+            ops->cdap_stop == NULL)
+                return NULL;
+
+        instance = malloc(sizeof(*instance));
+        if (instance == NULL)
+                return NULL;
+
+        if (pthread_mutex_init(&instance->ids_lock, NULL)) {
+                free(instance);
+                return NULL;
+        }
+
+        instance->ops = ops;
+
+        instance->ids = bmp_create(IDS_SIZE, 0);
+        if (instance->ids == NULL) {
+                free(instance);
+                return NULL;
+        }
+
+        pthread_create(&instance->reader,
+                       NULL,
+                       sdu_reader,
+                       (void *) instance);
+
+        return instance;
+}
+
+int cdap_destroy(struct cdap * instance)
+{
+        if (instance == NULL)
+                return -1;
+
+        pthread_cancel(instance->reader);
+
+        pthread_mutex_lock(&instance->ids_lock);
+
+        bmp_destroy(instance->ids);
+
+        pthread_mutex_unlock(&instance->ids_lock);
+
+        pthread_join(instance->reader,
+                     NULL);
+
+        free(instance);
+
+        return 0;
+}
+
+static int next_invoke_id(struct cdap * instance)
+{
+        int ret;
+
+        pthread_mutex_lock(&instance->ids_lock);
+        ret = bmp_allocate(instance->ids);
+        pthread_mutex_unlock(&instance->ids_lock);
+
+        return ret;
+}
+
+static int release_invoke_id(struct cdap * instance,
+                             int id)
+{
+        int ret;
+
+        pthread_mutex_lock(&instance->ids_lock);
+        ret = bmp_release(instance->ids, id);
+        pthread_mutex_unlock(&instance->ids_lock);
+
+        return ret;
+}
+
+static int write_msg(struct cdap * instance,
+                     cdap_t * msg)
+{
+        buffer_t buf;
+
+        buf.len = cdap__get_packed_size(msg);
+        if (buf.len == 0) {
+                return -1;
+        }
+
+        cdap__pack(msg, buf.data);
+
+        return flow_write(instance->fd, buf.data, buf.len);
+}
+
+static int buffer_to_cdap_msg(cdap_t * msg,
+                              buffer_t * val,
+                              size_t len)
+{
+        int i;
+
+        msg->value = malloc(len * sizeof(*msg->value));
+        if (msg->value == NULL) {
+                return -1;
+        }
+
+        msg->n_value = len;
+        for (i = 0; i < len; i++) {
+                if (val[i].data == NULL) {
+                        free(msg->value);
+                        return -1;
+                }
+
+                msg->value[i].data = val[i].data;
+                msg->value[i].len = val[i].len;
+        }
+
+        return 0;
+}
+
+static int send_read_or_start_or_stop(struct cdap * instance,
+                                      char *        name,
+                                      opcode_t      code)
+{
+        int id;
+        cdap_t msg = CDAP__INIT;
+
+        if (instance == NULL || name == NULL)
+                return -1;
+
+        id = next_invoke_id(instance);
+        if (!bmp_is_id_valid(instance->ids, id))
+                return -1;
+
+        msg.opcode = code;
+        msg.invoke_id = id;
+        msg.name = name;
+
+        return write_msg(instance, &msg);
+}
+
+static int send_create_or_delete(struct cdap * instance,
+                                 char *        name,
+                                 buffer_t      val,
+                                 opcode_t      code)
+{
+        int id;
+        cdap_t msg = CDAP__INIT;
+        int ret;
+
+        if (instance == NULL || name == NULL)
+                return -1;
+
+        id = next_invoke_id(instance);
+        if (!bmp_is_id_valid(instance->ids, id))
+                return -1;
+
+        msg.opcode = code;
+        msg.name = name;
+        msg.invoke_id = id;
+
+        if (buffer_to_cdap_msg(&msg, &val, 1)) {
+                release_invoke_id(instance, id);
+                return -1;
+        }
+
+        ret = write_msg(instance, &msg);
+
+        free(msg.value);
+
+        return ret;
+}
+
+int cdap_send_read(struct cdap * instance,
+                   char *        name)
+{
+        return send_read_or_start_or_stop(instance, name, OPCODE__READ);
+}
+
+int cdap_send_write(struct cdap * instance,
+                    char *        name,
+                    buffer_t *    val,
+                    size_t        len,
+                    uint32_t      flags)
+{
+        int id;
+        int ret;
+        cdap_t msg = CDAP__INIT;
+
+        if (instance == NULL || name == NULL ||
+            val == NULL || len < 1)
+                return -1;
+
+        id = next_invoke_id(instance);
+        if (!bmp_is_id_valid(instance->ids, id))
+                return -1;
+
+        msg.opcode = OPCODE__WRITE;
+        msg.name = name;
+        msg.has_flags = true;
+        msg.flags = flags;
+        msg.invoke_id = id;
+
+        if (buffer_to_cdap_msg(&msg, val, len)) {
+                release_invoke_id(instance, id);
+                return -1;
+        }
+
+        ret = write_msg(instance, &msg);
+
+        free(msg.value);
+
+        return ret;
+}
+
+int cdap_send_create(struct cdap * instance,
+                     char *        name,
+                     buffer_t      val)
+{
+        return send_create_or_delete(instance, name, val, OPCODE__CREATE);
+}
+
+int cdap_send_delete(struct cdap * instance,
+                     char *        name,
+                     buffer_t      val)
+{
+        return send_create_or_delete(instance, name, val, OPCODE__DELETE);
+}
+
+int cdap_send_start(struct cdap * instance,
+                    char *        name)
+{
+        return send_read_or_start_or_stop(instance, name, OPCODE__START);
+}
+
+int cdap_send_stop(struct cdap * instance,
+                   char *        name)
+{
+        return send_read_or_start_or_stop(instance, name, OPCODE__STOP);
+}
+
+int cdap_send_reply(struct cdap * instance,
+                    int           invoke_id,
+                    int           result,
+                    buffer_t *    val,
+                    size_t        len)
+{
+        cdap_t msg = CDAP__INIT;
+
+        if (instance == NULL || val == NULL)
+                return -1;
+
+        msg.invoke_id = invoke_id;
+        msg.has_result = true;
+        msg.result = result;
+
+        if (buffer_to_cdap_msg(&msg, val, len)) {
+                return -1;
+        }
+
+        return write_msg(instance, &msg);
+}
diff --git a/src/lib/cdap.proto b/src/lib/cdap.proto
new file mode 100644
index 00000000..a5e0306d
--- /dev/null
+++ b/src/lib/cdap.proto
@@ -0,0 +1,18 @@
+enum opcode {
+	CREATE = 1;
+	DELETE = 2;
+	READ   = 3;
+	WRITE  = 4;
+	START  = 5;
+	STOP   = 6;
+	REPLY  = 7;
+}
+
+message cdap {
+	required opcode opcode    = 1;
+	required uint32 invoke_id = 2;
+	optional uint32 flags     = 3;
+	optional string name      = 4;
+	repeated bytes value      = 5;
+	optional int32 result     = 6;
+}
diff --git a/src/lib/ipcp.c b/src/lib/ipcp.c
index 2b6b6825..b336155e 100644
--- a/src/lib/ipcp.c
+++ b/src/lib/ipcp.c
@@ -32,6 +32,8 @@
 #include <stdlib.h>
 #include <string.h>
 #include <signal.h>
+#include <errno.h>
+#include <stdbool.h>
 #include <sys/types.h>
 #include <sys/wait.h>
 
@@ -54,8 +56,8 @@ static ipcp_msg_t * send_recv_ipcp_msg(pid_t api,
                return NULL;
        }
 
-       buf.size = ipcp_msg__get_packed_size(msg);
-       if (buf.size == 0) {
+       buf.len = ipcp_msg__get_packed_size(msg);
+       if (buf.len == 0) {
                close(sockfd);
                free(sock_path);
                return NULL;
@@ -70,7 +72,7 @@ static ipcp_msg_t * send_recv_ipcp_msg(pid_t api,
 
        ipcp_msg__pack(msg, buf.data);
 
-       if (write(sockfd, buf.data, buf.size) == -1) {
+       if (write(sockfd, buf.data, buf.len) == -1) {
                free(sock_path);
                free(buf.data);
                close(sockfd);
diff --git a/src/lib/irm.c b/src/lib/irm.c
index 93963eb1..da3cfb62 100644
--- a/src/lib/irm.c
+++ b/src/lib/irm.c
@@ -28,6 +28,7 @@
 #include <ouroboros/logs.h>
 #include <ouroboros/sockets.h>
 
+#include <stdbool.h>
 #include <stdlib.h>
 #include <sys/stat.h>
 
diff --git a/src/lib/shm_du_map.c b/src/lib/shm_du_map.c
index 31fcca8e..cf0bad19 100644
--- a/src/lib/shm_du_map.c
+++ b/src/lib/shm_du_map.c
@@ -25,6 +25,7 @@
 #include <ouroboros/shm_du_map.h>
 #include <ouroboros/shm_ap_rbuff.h>
 #include <ouroboros/time_utils.h>
+
 #include <pthread.h>
 #include <sys/mman.h>
 #include <fcntl.h>
diff --git a/src/lib/sockets.c b/src/lib/sockets.c
index 9bfbad5e..d60ea91a 100644
--- a/src/lib/sockets.c
+++ b/src/lib/sockets.c
@@ -32,6 +32,7 @@
 #include <sys/un.h>
 #include <string.h>
 #include <stdlib.h>
+#include <errno.h>
 
 int client_socket_open(char * file_name)
 {
@@ -109,8 +110,8 @@ irm_msg_t * send_recv_irm_msg(irm_msg_t * msg)
         if (sockfd < 0)
                 return NULL;
 
-        buf.size = irm_msg__get_packed_size(msg);
-        if (buf.size == 0) {
+        buf.len = irm_msg__get_packed_size(msg);
+        if (buf.len == 0) {
                 close(sockfd);
                 return NULL;
         }
@@ -123,7 +124,7 @@ irm_msg_t * send_recv_irm_msg(irm_msg_t * msg)
 
         irm_msg__pack(msg, buf.data);
 
-        if (write(sockfd, buf.data, buf.size) == -1) {
+        if (write(sockfd, buf.data, buf.len) == -1) {
                 free(buf.data);
                 close(sockfd);
                 return NULL;