lib: Provide RIB API to export internals via fuse

This adds a virtual RIB that is accessible as a filesystem that is
accessed through a fuse mountpoint (configurable , default is
/tmp/ouroboros). Currently, each IPCP will export its link state
database.

3 files changed, 417 insertions, 4 deletions

diff --git a/src/lib/CMakeLists.txt b/src/lib/CMakeLists.txt
index fd7ece83..26cecb44 100644
--- a/src/lib/CMakeLists.txt
+++ b/src/lib/CMakeLists.txt
@@ -37,10 +37,30 @@ if (HAVE_ROBUST_MUTEX)
     set(HAVE_ROBUST_MUTEX TRUE)
   else ()
     message(STATUS "Robust mutex support disabled by user")
-    set(HAVE_ROBUST_MUTEX FALSE)
   endif ()
 endif ()
 
+find_library(FUSE_LIBRARIES fuse QUIET)
+if (FUSE_LIBRARIES)
+  #FIXME: Check for version >= 2.6
+  set(DISABLE_FUSE FALSE CACHE BOOL "Disable FUSE support")
+  if (NOT DISABLE_FUSE)
+    message(STATUS "FUSE support enabled")
+    set(FUSE_PREFIX "/tmp/ouroboros" CACHE STRING
+    "Mountpoint for RIB filesystem")
+    set(HAVE_FUSE TRUE CACHE INTERNAL "")
+  else ()
+    message(STATUS "FUSE support disabled by user")
+  endif ()
+endif ()
+
+if (NOT HAVE_FUSE)
+  set(FUSE_LIBRARIES "")
+  set(FUSE_INCLUDE_DIR "")
+endif ()
+
+mark_as_advanced(FUSE_LIBRARIES)
+
 find_library(LIBGCRYPT_LIBRARIES gcrypt QUIET)
 if (LIBGCRYPT_LIBRARIES)
   find_path(LIBGCRYPT_INCLUDE_DIR gcrypt.h
@@ -163,6 +183,7 @@ set(SOURCE_FILES
   qos.c
   qoscube.c
   random.c
+  rib.c
   rq.c
   sha3.c
   shm_flow_set.c
@@ -188,7 +209,7 @@ endif (CMAKE_BUILD_TYPE MATCHES Debug)
 
 target_link_libraries(ouroboros ${LIBRT_LIBRARIES}
   ${LIBPTHREAD_LIBRARIES} ${PROTOBUF_C_LIBRARY} ${OPENSSL_LIBRARIES}
-  ${LIBGCRYPT_LIBRARIES})
+  ${LIBGCRYPT_LIBRARIES} ${FUSE_LIBRARIES})
 
 install(TARGETS ouroboros LIBRARY DESTINATION usr/lib)
 
diff --git a/src/lib/config.h.in b/src/lib/config.h.in
index e9c43389..a85ce7b4 100644
--- a/src/lib/config.h.in
+++ b/src/lib/config.h.in
@@ -45,6 +45,11 @@
 #cmakedefine HAVE_ROBUST_MUTEX
 #endif
 
+#cmakedefine HAVE_FUSE
+#ifdef HAVE_FUSE
+#define FUSE_PREFIX "@FUSE_PREFIX@"
+#endif
+
 #define PTHREAD_COND_CLOCK  @PTHREAD_COND_CLOCK@
 
 #define AP_MAX_FLOWS        @AP_MAX_FLOWS@
@@ -53,5 +58,3 @@
 
 #define DU_BUFF_HEADSPACE   @DU_BUFF_HEADSPACE@
 #define DU_BUFF_TAILSPACE   @DU_BUFF_TAILSPACE@
-
-#define CDAP_REPLY_TIMEOUT  @CDAP_REPLY_TIMEOUT@
diff --git a/src/lib/rib.c b/src/lib/rib.c
new file mode 100644
index 00000000..b6c8e140
--- /dev/null
+++ b/src/lib/rib.c
@@ -0,0 +1,389 @@
+/*
+ * Ouroboros - Copyright (C) 2016 - 2017
+ *
+ * RIB export using FUSE
+ *
+ *    Dimitri Staessens <dimitri.staessens@ugent.be>
+ *    Sander Vrijders   <sander.vrijders@ugent.be>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public License
+ * version 2.1 as published by the Free Software Foundation.
+ *
+ * This library 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
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., http://www.fsf.org/about/contact/.
+ */
+
+#define _POSIX_C_SOURCE 200112L
+
+#include "config.h"
+
+#include <ouroboros/errno.h>
+#include <ouroboros/list.h>
+#include <ouroboros/rib.h>
+#include <ouroboros/utils.h>
+
+#include <pthread.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#ifdef HAVE_FUSE
+#define _FILE_OFFSET_BITS 64
+#define FUSE_USE_VERSION  26
+#include <fuse.h>
+#endif
+
+#ifdef HAVE_FUSE
+
+#ifndef CLOCK_REALTIME_COARSE
+#define CLOCK_REALTIME_COARSE CLOCK_REALTIME
+#endif
+
+#define RT "/"
+
+struct reg_comp {
+        struct list_head next;
+
+        char             path[RIB_PATH_LEN + 1];
+        struct rib_ops * ops;
+};
+
+struct {
+        struct list_head   reg_comps;
+
+        char               mnt[RIB_PATH_LEN + 1];
+
+        struct fuse *      fuse;
+        struct fuse_chan * ch;
+
+        pthread_rwlock_t   lock;
+
+        pthread_t          fuse_thr;
+} rib;
+
+static int rib_open(const char *            path,
+                    struct fuse_file_info * info)
+{
+        (void) path;
+
+        info->nonseekable = 1;
+
+        return 0;
+}
+
+static int rib_opendir(const char *         path,
+                    struct fuse_file_info * info)
+{
+        (void) path;
+        (void) info;
+
+        return 0;
+}
+
+static int rib_read(const char *            path,
+                    char *                  buf,
+                    size_t                  size,
+                    off_t                   offset,
+                    struct fuse_file_info * info)
+{
+        struct list_head * p;
+        char               comp[RIB_PATH_LEN + 1];
+        char *             c;
+
+        strcpy(comp, path + 1);
+
+        c = strstr(comp, "/");
+
+        if (c != NULL)
+                *c = '\0';
+
+        (void) info;
+        (void) offset;
+
+        pthread_rwlock_wrlock(&rib.lock);
+
+        list_for_each(p, &rib.reg_comps) {
+                struct reg_comp * r = list_entry(p, struct reg_comp, next);
+                if (strcmp(comp, r->path) == 0) {
+                        int ret = r->ops->read(c + 1, buf, size);
+                        pthread_rwlock_unlock(&rib.lock);
+                        return ret;
+                }
+        }
+
+        pthread_rwlock_unlock(&rib.lock);
+
+        return -1;
+}
+
+static int rib_readdir(const char *            path,
+                       void *                  buf,
+                       fuse_fill_dir_t         filler,
+                       off_t                   offset,
+                       struct fuse_file_info * info)
+{
+        struct list_head * p;
+
+        (void) offset;
+        (void) info;
+
+        filler(buf, ".", NULL, 0);
+        filler(buf, "..", NULL, 0);
+
+        pthread_rwlock_rdlock(&rib.lock);
+
+        if (strcmp(path, RT) == 0) {
+                list_for_each(p, &rib.reg_comps) {
+                        struct reg_comp * c;
+                        c = list_entry(p, struct reg_comp, next);
+                        filler(buf, c->path, NULL, 0);
+                }
+        } else {
+                list_for_each(p, &rib.reg_comps) {
+                        char **           dir_entries;
+                        ssize_t           len;
+                        ssize_t           i;
+                        struct reg_comp * c;
+                        c = list_entry(p, struct reg_comp, next);
+                        if (strcmp(path + 1, c->path) == 0)
+                                if (c->ops->readdir == NULL)
+                                        break;
+
+                        len = c->ops->readdir(&dir_entries);
+                        if (len < 0)
+                                break;
+                        for (i = 0; i < len; ++i)
+                                filler(buf, dir_entries[i], NULL, 0);
+                        freepp(char, dir_entries, len);
+                }
+        }
+
+        pthread_rwlock_unlock(&rib.lock);
+
+        return 0;
+}
+
+static int rib_getattr(const char *  path,
+                       struct stat * st)
+{
+        struct list_head * p;
+        struct timespec    now;
+
+        clock_gettime(CLOCK_REALTIME_COARSE, &now);
+
+        memset(st, 0, sizeof(*st));
+
+        if (strcmp(path, RT) == 0) {
+                st->st_mode  = __S_IFDIR | 0755;
+                st->st_nlink = 2;
+                st->st_uid   = getuid();
+                st->st_gid   = getgid();
+                st->st_mtime = now.tv_sec;
+                return 0;
+        }
+
+        pthread_rwlock_rdlock(&rib.lock);
+
+        list_for_each(p, &rib.reg_comps) {
+                struct reg_comp * rc = list_entry(p, struct reg_comp, next);
+                if (strcmp(path + 1, rc->path) == 0) {
+                        st->st_mode  = __S_IFDIR | 0755;
+                        st->st_nlink = 2;
+                        break;
+                }
+        }
+
+        pthread_rwlock_unlock(&rib.lock);
+
+        if (st->st_mode == 0) {
+                char buf[4096];
+                st->st_nlink = 2;
+                st->st_mode = __S_IFREG | 0755;
+                st->st_size = rib_read(path, buf, 4096, 0, NULL);
+        }
+
+        st->st_uid   = getuid();
+        st->st_gid   = getgid();
+        st->st_mtime = now.tv_sec;
+
+        return 0;
+}
+
+static struct fuse_operations r_ops = {
+        .getattr = rib_getattr,
+        .open    = rib_open,
+        .opendir = rib_opendir,
+        .read    = rib_read,
+        .readdir = rib_readdir
+};
+
+static void * fuse_thr(void * o)
+{
+        (void) o;
+
+        if (fuse_loop(rib.fuse) < 0)
+                return (void *) -1;
+
+        return (void *) 0;
+}
+#endif /* HAVE_FUSE */
+
+int rib_init(const char * prefix)
+{
+#ifdef HAVE_FUSE
+        struct stat      st;
+        char *           argv[] = {"ignored",
+                                   NULL,
+                                   "-f",
+                                   "-o",
+                                   "ro,",
+                                   "allow_other,",
+                                   "default_permissions,",
+                                   "fsname=rib",
+                                   NULL};
+        struct fuse_args args   = FUSE_ARGS_INIT(0, NULL);
+
+        if (stat(FUSE_PREFIX, &st) == -1)
+                return -1;
+
+        sprintf(rib.mnt, FUSE_PREFIX "/%s.%d", prefix, getpid());
+
+        if (stat(rib.mnt, &st) == -1)
+                mkdir(rib.mnt, 0777);
+
+        argv[1] = rib.mnt;
+
+        fuse_opt_parse(&args, argv, NULL, NULL);
+
+        list_head_init(&rib.reg_comps);
+
+        rib.ch = fuse_mount(rib.mnt,  &args);
+        if (rib.ch == NULL)
+                goto fail_mount;
+
+        rib.fuse = fuse_new(rib.ch, &args, &r_ops, sizeof(r_ops), NULL);
+        if (rib.fuse == NULL)
+                goto fail_fuse;
+
+        if (pthread_rwlock_init(&rib.lock, NULL))
+                goto fail_rwlock_init;
+
+        if (pthread_create(&rib.fuse_thr, NULL, fuse_thr, NULL))
+                goto fail_fuse_thr;
+
+        fuse_opt_free_args(&args);
+
+        return 0;
+
+ fail_fuse_thr:
+        pthread_rwlock_destroy(&rib.lock);
+ fail_rwlock_init:
+        fuse_destroy(rib.fuse);
+ fail_fuse:
+        fuse_unmount(rib.mnt, rib.ch);
+ fail_mount:
+        fuse_opt_free_args(&args);
+        rmdir(rib.mnt);
+        return -1;
+#else
+        (void) prefix;
+        return 0;
+#endif
+}
+
+void rib_fini(void)
+{
+#ifdef HAVE_FUSE
+        struct list_head * p;
+        struct list_head * h;
+
+        fuse_unmount(rib.mnt, rib.ch);
+        pthread_join(rib.fuse_thr, NULL);
+
+        fuse_destroy(rib.fuse);
+
+        rmdir(rib.mnt);
+
+        pthread_rwlock_wrlock(&rib.lock);
+
+        list_for_each_safe(p, h, &rib.reg_comps) {
+                struct reg_comp * c = list_entry(p, struct reg_comp, next);
+                list_del(&c->next);
+                free(c);
+        }
+
+        pthread_rwlock_unlock(&rib.lock);
+
+        pthread_rwlock_destroy(&rib.lock);
+#endif
+}
+
+int rib_reg(const char *     path,
+            struct rib_ops * ops)
+{
+#ifdef HAVE_FUSE
+        struct reg_comp *  rc;
+        struct list_head * p;
+
+        pthread_rwlock_wrlock(&rib.lock);
+
+        list_for_each(p, &rib.reg_comps) {
+                struct reg_comp * r = list_entry(p, struct reg_comp, next);
+                if (strcmp(r->path, path) == 0) {
+                        pthread_rwlock_unlock(&rib.lock);
+                        return -EPERM;
+                }
+
+                if (strcmp(r->path, path) > 0)
+                        break;
+        }
+
+        rc = malloc(sizeof(*rc));
+        if (rc == NULL) {
+                pthread_rwlock_unlock(&rib.lock);
+                return -ENOMEM;
+        }
+
+        strcpy(rc->path, path);
+        rc->ops = ops;
+
+        list_add_tail(&rc->next, p);
+
+        pthread_rwlock_unlock(&rib.lock);
+#else
+        (void) path;
+        (void) ops;
+#endif
+        return 0;
+}
+
+void rib_unreg(const char * path)
+{
+#ifdef HAVE_FUSE
+        struct list_head * p;
+        struct list_head * h;
+
+        pthread_rwlock_wrlock(&rib.lock);
+
+        list_for_each_safe(p, h, &rib.reg_comps) {
+                struct reg_comp * r = list_entry(p, struct reg_comp, next);
+                if (strcmp(r->path, path) == 0) {
+                        list_del(&r->next);
+                        free(r);
+                        break;
+                }
+        }
+
+        pthread_rwlock_unlock(&rib.lock);
+#else
+        (void) path;
+#endif
+}