irmd: flow allocation and fast path

This commit has a first implementation of flow allocation (the "slow
path") and read/write (the "fast path") for ouroboros. It provides
basic but unstable communications over the shared memory.

It required a lot of changes all over the stack, and fixes a number of
previously undetected issues.

This PR still need heavy revision regarding data model, locking and
cleanup.

lib/dev: modifications to the API. It now uses an ap_init() call to
set the AP name and sets the Instance ID to the pid of the process. It
also binds the AP to the shared memory and creates tables for mappings
in the fast path. A call to ap_fini() releases the resources.

lib/shm_ap_rbuff: added ring buffer for data exchange between
processes in the fast path. It passes an index in the shm_du_map.

lib/shm_du_map: rewrote API to work with calls from dev.c. Garbage
collector added. Tests updated to new API.

ipcpd/ipcp-data: removed everything related to flows, as these are
universal for all ap's and kept in ap_data (dev.c), or similar structs
for shim ipcps.

shim-udp: added flow allocator and read/write functions and shm
elements.

irmd: revised data model and structures necessary for flow allocation.

tools: echo updated to new dev.h API.

messaging system was updated to comply with new flow allocation
messages. All exchanges use pid and port_id to bootstrap the fast
path.

7 files changed, 127 insertions, 14 deletions

diff --git a/include/ouroboros/CMakeLists.txt b/include/ouroboros/CMakeLists.txt
index cfa299ca..6a247e8e 100644
--- a/include/ouroboros/CMakeLists.txt
+++ b/include/ouroboros/CMakeLists.txt
@@ -15,6 +15,7 @@ set(HEADER_FILES
         irm.h
         list.h
         logs.h
+        shm_ap_rbuff.h
         shm_du_map.h
         sockets.h
         utils.h
diff --git a/include/ouroboros/dev.h b/include/ouroboros/dev.h
index 414273ef..e857e211 100644
--- a/include/ouroboros/dev.h
+++ b/include/ouroboros/dev.h
@@ -24,29 +24,34 @@
 #define OUROBOROS_DEV_H
 
 #include <ouroboros/common.h>
+#include <ouroboros/flow.h>
 
 #define UNKNOWN_AP "__UNKNOWN_AP__"
 #define UNKNOWN_AE "__UNKNOWN_AE__"
 
+/* These calls should be removed once we write the ouroboros OS. */
+int     ap_init(char * ap_name);
+void    ap_fini();
+
 /* Returns file descriptor */
-int     ap_reg(char * ap_name, char ** difs, size_t difs_size);
-int     ap_unreg(char * ap_name, char ** difs, size_t difs_size);
+int     ap_reg(char ** difs, size_t difs_size);
+int     ap_unreg(char ** difs, size_t difs_size);
 
 /* Returns file descriptor (> 0) and client name(s) */
-int     flow_accept(int fd, char * ap_name, char * ae_name);
+int     flow_accept(int fd, char ** ap_name, char ** ae_name);
 int     flow_alloc_resp(int fd, int result);
 
 /* Returns file descriptor */
-int     flow_alloc(char * dst_ap_name, char * src_ap_name,
-                   char * src_ae_name, struct qos_spec * qos,
-                   int oflags);
+int     flow_alloc(char * dst_name,
+                   char * src_ae_name,
+                   struct qos_spec * qos);
 
 /* If flow is accepted returns a value > 0 */
 int     flow_alloc_res(int fd);
 int     flow_dealloc(int fd);
 
 /* Wraps around fnctl */
-int     flow_cntl(int fd, int oflags);
+int     flow_cntl(int fd, int cmd, int oflags);
 ssize_t flow_write(int fd, void * buf, size_t count);
 ssize_t flow_read(int fd, void * buf, size_t count);
 
diff --git a/include/ouroboros/flow.h b/include/ouroboros/flow.h
new file mode 100644
index 00000000..ff9085f7
--- /dev/null
+++ b/include/ouroboros/flow.h
@@ -0,0 +1,43 @@
+/*
+ * Ouroboros - Copyright (C) 2016
+ *
+ * Flows
+ *
+ *    Dimitri Staessens <dimitri.staessens@intec.ugent.be>
+ *
+ * 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_FLOW_H
+#define OUROBOROS_FLOW_H
+
+/* same values as fcntl.h */
+#define FLOW_O_RDONLY   00000000
+#define FLOW_O_WRONLY   00000001
+#define FLOW_O_RDWR     00000002
+#define FLOW_O_ACCMODE  00000003
+
+#define FLOW_O_NONBLOCK 00004000
+#define FLOW_O_DEFAULT  00000002
+
+#define FLOW_O_INVALID  (FLOW_O_WRONLY | FLOW_O_RDWR)
+
+enum flow_state {
+        FLOW_NULL = 0,
+        FLOW_ALLOCATED,
+        FLOW_PENDING
+};
+
+#endif /* OUROBOROS_FLOW_H */
diff --git a/include/ouroboros/ipcp.h b/include/ouroboros/ipcp.h
index e3c17bda..570eca67 100644
--- a/include/ouroboros/ipcp.h
+++ b/include/ouroboros/ipcp.h
@@ -61,13 +61,15 @@ int   ipcp_name_unreg(pid_t    pid,
 
 int   ipcp_flow_alloc(pid_t             pid,
                       uint32_t          port_id,
+                      pid_t             n_pid,
                       char *            dst_name,
                       char *            src_ap_name,
                       char *            src_ae_name,
                       struct qos_spec * qos);
 int   ipcp_flow_alloc_resp(pid_t    pid,
                            uint32_t port_id,
-                           int      result);
+                           pid_t    n_pid,
+                           int      response);
 
 /* These operations go from the IPCP to the IRMd */
 
diff --git a/include/ouroboros/shm_ap_rbuff.h b/include/ouroboros/shm_ap_rbuff.h
new file mode 100644
index 00000000..070542b0
--- /dev/null
+++ b/include/ouroboros/shm_ap_rbuff.h
@@ -0,0 +1,52 @@
+/*
+ * Ouroboros - Copyright (C) 2016
+ *
+ * Ring buffer for application processes
+ *
+ *    Dimitri Staessens <dimitri.staessens@intec.ugent.be>
+ *    Sander Vrijders   <sander.vrijders@intec.ugent.be>
+ *
+ * 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_SHM_AP_RBUFF_H
+#define OUROBOROS_SHM_AP_RBUFF_H
+
+#ifndef SHM_AP_RBUFF
+#define SHM_AP_RBUFF "ouroboros_rb_"
+#endif
+
+#ifndef SHM_RBUFF_SIZE
+#define SHM_RBUFF_SIZE (1 << 12)
+#endif
+
+#include <sys/types.h>
+
+struct shm_ap_rbuff;
+
+struct rb_entry {
+        size_t index;
+        int    port_id;
+};
+
+struct shm_ap_rbuff * shm_ap_rbuff_create();
+struct shm_ap_rbuff * shm_ap_rbuff_open();
+void                  shm_ap_rbuff_close(struct shm_ap_rbuff * rb);
+void                  shm_ap_rbuff_destroy(struct shm_ap_rbuff * rb);
+int                   shm_ap_rbuff_write(struct shm_ap_rbuff * rb,
+                                         struct rb_entry * e);
+struct rb_entry *     shm_ap_rbuff_read();
+
+#endif /* OUROBOROS_SHM_AP_RBUFF_H */
diff --git a/include/ouroboros/shm_du_map.h b/include/ouroboros/shm_du_map.h
index fb51768d..f575aa42 100644
--- a/include/ouroboros/shm_du_map.h
+++ b/include/ouroboros/shm_du_map.h
@@ -44,14 +44,23 @@ struct shm_du_map;
 struct shm_du_map  * shm_du_map_create();
 struct shm_du_map  * shm_du_map_open();
 void                 shm_du_map_close(struct shm_du_map * dum);
+void                 shm_du_map_destroy(struct shm_du_map * dum);
 
-struct shm_du_buff * shm_create_du_buff(struct shm_du_map * dum,
-                                        size_t              size,
-                                        size_t              headspace,
-                                        uint8_t           * data,
-                                        size_t              len);
-int                  shm_release_du_buff(struct shm_du_map  * dum);
+/* returns the index of the buffer in the DU map */
+int shm_create_du_buff(struct shm_du_map * dum,
+                       size_t              size,
+                       size_t              headspace,
+                       uint8_t           * data,
+                       size_t              len);
 
+/* FIXME: revise these */
+int       shm_du_map_read_sdu(uint8_t **           dst,
+                               struct shm_du_map * dum,
+                               size_t              idx);
+int       shm_release_du_buff(struct shm_du_map  * dum, size_t idx);
+
+
+/* FIXME: use shm_du_map * and index */
 uint8_t * shm_du_buff_head_alloc(struct shm_du_buff * sdb,
                                  size_t size);
 uint8_t * shm_du_buff_tail_alloc(struct shm_du_buff * sdb,
diff --git a/include/ouroboros/utils.h b/include/ouroboros/utils.h
index 2e5a4944..a1d2ac96 100644
--- a/include/ouroboros/utils.h
+++ b/include/ouroboros/utils.h
@@ -21,6 +21,7 @@
  */
 
 #define MAX(a,b) (a > b ? a : b)
+#define MIN(a,b) (a < b ? a : b)
 
 /*
  * Returns the number of characters a uint would