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.

1 files changed, 268 insertions, 0 deletions

diff --git a/src/lib/shm_ap_rbuff.c b/src/lib/shm_ap_rbuff.c
new file mode 100644
index 00000000..4bd64775
--- /dev/null
+++ b/src/lib/shm_ap_rbuff.c
@@ -0,0 +1,268 @@
+/*
+ * Ouroboros - Copyright (C) 2016
+ *
+ * Ring buffer for application processes
+ *
+ *    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
+ * 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/shm_ap_rbuff.h>
+#define OUROBOROS_PREFIX "shm_ap_rbuff"
+
+#include <ouroboros/logs.h>
+
+#include <pthread.h>
+#include <sys/mman.h>
+#include <fcntl.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdint.h>
+#include <unistd.h>
+#include <stdbool.h>
+#include <errno.h>
+
+#define SHM_RBUFF_FILE_SIZE (SHM_RBUFF_SIZE * sizeof(struct rb_entry)          \
+                             + 2 * sizeof(size_t) + sizeof(pthread_mutex_t))
+
+#define shm_rbuff_used(rb)((*rb->ptr_head + SHM_RBUFF_SIZE - *rb->ptr_tail)\
+                          & (SHM_RBUFF_SIZE - 1))
+#define shm_rbuff_free(rb)(shm_rbuff_used(rb) + 1 < SHM_RBUFF_SIZE)
+
+struct shm_ap_rbuff {
+        struct rb_entry * shm_base;    /* start of entry */
+        size_t *          ptr_head;    /* start of ringbuffer head */
+        size_t *          ptr_tail;    /* start of ringbuffer tail */
+        pthread_mutex_t * shm_mutex;   /* lock all free space in shm */
+        pid_t             pid;         /* pid to which this rb belongs */
+        int               fd;
+};
+
+struct shm_ap_rbuff * shm_ap_rbuff_create()
+{
+        struct shm_ap_rbuff * rb;
+        int                   shm_fd;
+        struct rb_entry *     shm_base;
+        pthread_mutexattr_t   attr;
+        char                  fn[25];
+
+        sprintf(fn, SHM_AP_RBUFF "%d", getpid());
+
+        rb = malloc(sizeof(*rb));
+        if (rb == NULL) {
+                LOG_DBGF("Could not allocate struct.");
+                return NULL;
+        }
+
+        shm_fd = shm_open(fn, O_CREAT | O_EXCL | O_RDWR, 0666);
+        if (shm_fd == -1) {
+                LOG_DBGF("Failed creating ring buffer.");
+                free(rb);
+                return NULL;
+        }
+
+        if (lseek(shm_fd, SHM_RBUFF_FILE_SIZE - 1, SEEK_SET) < 0) {
+                LOG_DBGF("Failed to extend ringbuffer.");
+                free(rb);
+                return NULL;
+        }
+
+        if (write(shm_fd, "", 1) != 1) {
+                LOG_DBGF("Failed to finalise extension of ringbuffer.");
+                free(rb);
+                return NULL;
+        }
+
+        shm_base = mmap(NULL,
+                        SHM_RBUFF_FILE_SIZE,
+                        PROT_READ | PROT_WRITE,
+                        MAP_SHARED,
+                        shm_fd,
+                        0);
+
+        if (shm_base == MAP_FAILED) {
+                LOG_DBGF("Failed to map shared memory.");
+                if (close(shm_fd) == -1)
+                        LOG_DBGF("Failed to close invalid shm.");
+
+                if (shm_unlink(fn) == -1)
+                        LOG_DBGF("Failed to remove invalid shm.");
+
+                free(rb);
+                return NULL;
+        }
+
+        rb->shm_base = shm_base;
+        rb->ptr_head = (size_t *) (rb->shm_base + SHM_RBUFF_SIZE);
+        rb->ptr_tail = (size_t *)
+                ((uint8_t *) rb->ptr_head + sizeof(size_t));
+        rb->shm_mutex = (pthread_mutex_t *)
+                ((uint8_t *) rb->ptr_tail + sizeof(size_t));
+
+        pthread_mutexattr_init(&attr);
+        pthread_mutexattr_setpshared(&attr, PTHREAD_PROCESS_SHARED);
+        pthread_mutex_init(rb->shm_mutex, &attr);
+
+        *rb->ptr_head = 0;
+        *rb->ptr_tail = 0;
+
+        rb->fd  = shm_fd;
+        rb->pid = getpid();
+
+        return rb;
+}
+
+struct shm_ap_rbuff * shm_ap_rbuff_open(pid_t pid)
+{
+        struct shm_ap_rbuff * rb;
+        int                   shm_fd;
+        struct rb_entry *     shm_base;
+        char                  fn[25];
+
+        sprintf(fn, SHM_AP_RBUFF "%d", pid);
+
+        rb = malloc(sizeof(*rb));
+        if (rb == NULL) {
+                LOG_DBGF("Could not allocate struct.");
+                return NULL;
+        }
+
+        shm_fd = shm_open(fn, O_RDWR, 0666);
+        if (shm_fd == -1) {
+                LOG_DBGF("Failed opening shared memory %s.", fn);
+                return NULL;
+        }
+
+        shm_base = mmap(NULL,
+                        SHM_RBUFF_FILE_SIZE,
+                        PROT_READ | PROT_WRITE,
+                        MAP_SHARED,
+                        shm_fd,
+                        0);
+
+        if (shm_base == MAP_FAILED) {
+                LOG_DBGF("Failed to map shared memory.");
+                if (close(shm_fd) == -1)
+                        LOG_DBGF("Failed to close invalid shm.");
+
+                if (shm_unlink(fn) == -1)
+                        LOG_DBGF("Failed to remove invalid shm.");
+
+                free(rb);
+                return NULL;
+        }
+
+        rb->shm_base = shm_base;
+        rb->ptr_head = (size_t *) (rb->shm_base + SHM_RBUFF_SIZE);
+        rb->ptr_tail = (size_t *)
+                ((uint8_t *) rb->ptr_head + sizeof(size_t));
+        rb->shm_mutex = (pthread_mutex_t *)
+                ((uint8_t *) rb->ptr_tail + sizeof(size_t));
+
+        rb->fd = shm_fd;
+        rb->pid = pid;
+
+        return rb;
+}
+void shm_ap_rbuff_close(struct shm_ap_rbuff * rb)
+{
+        char fn[25];
+
+        if (rb == NULL) {
+                LOG_DBGF("Bogus input. Bugging out.");
+                return;
+        }
+
+        sprintf(fn, SHM_AP_RBUFF "%d", rb->pid);
+
+        if (munmap(rb->shm_base, SHM_RBUFF_FILE_SIZE) == -1)
+                LOG_DBGF("Couldn't unmap shared memory.");
+
+        free(rb);
+}
+
+void shm_ap_rbuff_destroy(struct shm_ap_rbuff * rb)
+{
+        char fn[25];
+
+
+        if (rb == NULL) {
+                LOG_DBGF("Bogus input. Bugging out.");
+                return;
+        }
+
+        if (rb->pid != getpid()) {
+                LOG_ERR("Tried to destroy other AP's rbuff.");
+                return;
+        }
+
+        sprintf(fn, SHM_AP_RBUFF "%d", rb->pid);
+
+        if (munmap(rb->shm_base, SHM_RBUFF_FILE_SIZE) == -1)
+                LOG_DBGF("Couldn't unmap shared memory.");
+
+        if (shm_unlink(fn) == -1)
+                LOG_DBGF("Failed to unlink shm.");
+
+        free(rb);
+}
+
+int shm_ap_rbuff_write(struct shm_ap_rbuff * rb, struct rb_entry * e)
+{
+        struct rb_entry * pos;
+
+        if (rb == NULL || e == NULL)
+                return -1;
+
+        pthread_mutex_lock(rb->shm_mutex);
+
+        if (!shm_rbuff_free(rb)) {
+                pthread_mutex_unlock(rb->shm_mutex);
+                return -1;
+        }
+
+        pos = rb->shm_base + *rb->ptr_head;
+        *pos = *e;
+        *rb->ptr_head = (*rb->ptr_head + 1) & (SHM_RBUFF_SIZE -1);
+
+        pthread_mutex_unlock(rb->shm_mutex);
+
+        return 0;
+}
+struct rb_entry * shm_ap_rbuff_read(struct shm_ap_rbuff * rb)
+{
+        struct rb_entry * e = malloc(sizeof(*e));
+        if (e == NULL)
+                return NULL;
+
+        if (rb == NULL)
+                return NULL;
+
+        pthread_mutex_lock(rb->shm_mutex);
+
+        if (shm_rbuff_used(rb) == 0) {
+                pthread_mutex_unlock(rb->shm_mutex);
+                return NULL;
+        }
+
+        *e = *(rb->shm_base + *rb->ptr_tail);
+
+        *rb->ptr_tail = (*rb->ptr_tail + 1) & (SHM_RBUFF_SIZE -1);
+
+        pthread_mutex_unlock(rb->shm_mutex);
+
+        return e;
+}