/* This file is part of GNUnet (C) 2008--2013 Christian Grothoff (and other contributing authors) GNUnet 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 3, or (at your option) any later version. GNUnet 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 GNUnet; see the file COPYING. If not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ /** * @file testbed/testbed_api_topology.c * @brief topology-generation functions * @author Christian Grothoff */ #include "platform.h" #include "gnunet_testbed_service.h" #include "testbed_api.h" #include "testbed_api_peers.h" #include "testbed_api_operations.h" #include "testbed_api_topology.h" /** * Generic loggins shorthand */ #define LOG(kind,...) \ GNUNET_log_from (kind, "testbed-api-topology", __VA_ARGS__) /** * Default number of retires */ #define DEFAULT_RETRY_CNT 3 /** * Context information for topology operations */ struct TopologyContext; /** * Representation of an overlay link */ struct OverlayLink { /** * An operation corresponding to this link */ struct GNUNET_TESTBED_Operation *op; /** * The topology context this link is a part of */ struct TopologyContext *tc; /** * position of peer A's handle in peers array */ uint32_t A; /** * position of peer B's handle in peers array */ uint32_t B; }; struct RetryListEntry { /** * the next pointer for the DLL */ struct RetryListEntry *next; /** * the prev pointer for the DLL */ struct RetryListEntry *prev; /** * The link to be retired */ struct OverlayLink *link; }; /** * Context information for topology operations */ struct TopologyContext { /** * The array of peers */ struct GNUNET_TESTBED_Peer **peers; /** * An array of links; this array is of size link_array_size */ struct OverlayLink *link_array; /** * The operation closure */ void *op_cls; /** * topology generation completion callback */ GNUNET_TESTBED_TopologyCompletionCallback comp_cb; /** * The closure for the above callback */ void *comp_cb_cls; /** * DLL head for retry list */ struct RetryListEntry *rl_head; /** * DLL tail for retry list */ struct RetryListEntry *rl_tail; /** * The number of peers */ unsigned int num_peers; /** * The size of the link array */ unsigned int link_array_size; /** * How many retries to do before we give up */ unsigned int retry_cnt; /** * Number of links to try */ unsigned int nlinks; /** * How many links have been completed */ unsigned int ncompleted; /** * Total successfully established overlay connections */ unsigned int nsuccess; /** * Total failed overlay connections */ unsigned int nfailures; }; /** * A array of names representing topologies. Should be in sync with enum * GNUNET_TESTBED_TopologyOption */ const char *topology_strings[] = { /** * A clique (everyone connected to everyone else). No options. If there are N * peers this topology results in (N * (N -1)) connections. */ "CLIQUE", /** * Small-world network (2d torus plus random links). Followed * by the number of random links to add (unsigned int). */ "SMALL_WORLD", /** * Small-world network (ring plus random links). Followed * by the number of random links to add (unsigned int). */ "SMALL_WORLD_RING", /** * Ring topology. No options. */ "RING", /** * 2-d torus. No options. */ "2D_TORUS", /** * Random graph. Followed by the number of random links to be established * (unsigned int) */ "RANDOM", // GNUNET_TESTBED_TOPOLOGY_ERDOS_RENYI /** * Certain percentage of peers are unable to communicate directly * replicating NAT conditions. Followed by the fraction of * NAT'ed peers (float). */ "INTERNAT", /** * Scale free topology. No options. */ "SCALE_FREE", /** * Straight line topology. No options. */ "LINE", /** * Read a topology from a given file. Followed by the name of the file (const char *). */ "FROM_FILE", /** * All peers are disconnected. No options. */ "NONE", /** * End of strings */ NULL }; /** * Callback to be called when an overlay_link operation complete * * @param cls element of the link_op array which points to the corresponding operation * @param op the operation that has been finished * @param emsg error message in case the operation has failed; will be NULL if * operation has executed successfully. */ static void overlay_link_completed (void *cls, struct GNUNET_TESTBED_Operation *op, const char *emsg) { struct OverlayLink *link = cls; struct TopologyContext *tc; struct RetryListEntry *retry_entry; GNUNET_assert (op == link->op); GNUNET_TESTBED_operation_done (op); link->op = NULL; tc = link->tc; if (NULL != emsg) { tc->nfailures++; if (0 != tc->retry_cnt) { LOG (GNUNET_ERROR_TYPE_WARNING, "Error while establishing a link: %s -- Retrying\n", emsg); retry_entry = GNUNET_malloc (sizeof (struct RetryListEntry)); retry_entry->link = link; GNUNET_CONTAINER_DLL_insert_tail (tc->rl_head, tc->rl_tail, retry_entry); } } else tc->nsuccess++; tc->ncompleted++; if (tc->ncompleted < tc->nlinks) return; if ((0 != tc->retry_cnt) && (NULL != tc->rl_head)) { tc->retry_cnt--; tc->ncompleted = 0; tc->nlinks = 0; while (NULL != (retry_entry = tc->rl_head)) { link = retry_entry->link; link->op = GNUNET_TESTBED_overlay_connect (tc->op_cls, &overlay_link_completed, link, tc->peers[link->A], tc->peers[link->B]); tc->nlinks++; GNUNET_CONTAINER_DLL_remove (tc->rl_head, tc->rl_tail, retry_entry); GNUNET_free (retry_entry); } return; } if (NULL != tc->comp_cb) { tc->comp_cb (tc->comp_cb_cls, tc->nsuccess, tc->nfailures); } } /** * Function called when a overlay connect operation is ready * * @param cls the Topology context */ static void opstart_overlay_configure_topology (void *cls) { struct TopologyContext *tc = cls; unsigned int p; tc->nlinks = tc->link_array_size; for (p = 0; p < tc->link_array_size; p++) { tc->link_array[p].op = GNUNET_TESTBED_overlay_connect (tc->op_cls, &overlay_link_completed, &tc->link_array[p], tc->peers[tc->link_array[p].A], tc->peers[tc->link_array[p].B]); } } /** * Callback which will be called when overlay connect operation is released * * @param cls the Topology context */ static void oprelease_overlay_configure_topology (void *cls) { struct TopologyContext *tc = cls; struct RetryListEntry *retry_entry; unsigned int p; while (NULL != (retry_entry = tc->rl_head)) { GNUNET_CONTAINER_DLL_remove (tc->rl_head, tc->rl_tail, retry_entry); GNUNET_free (retry_entry); } if (NULL != tc->link_array) { for (p = 0; p < tc->link_array_size; p++) if (NULL != tc->link_array[p].op) GNUNET_TESTBED_operation_done (tc->link_array[p].op); GNUNET_free (tc->link_array); } GNUNET_free (tc); } /** * Populates the OverlayLink structure. * * @param link the OverlayLink * @param A the peer A. Should be different from B * @param B the peer B. Should be different from A * @param tc the TopologyContext * @return */ static void make_link (struct OverlayLink *link, uint32_t A, uint32_t B, struct TopologyContext *tc) { GNUNET_assert (A != B); LOG (GNUNET_ERROR_TYPE_DEBUG, "Connecting peer %u to %u\n", B, A); link->A = A; link->B = B; link->op = NULL; link->tc = tc; } /** * Generates line topology * * @param tc the topology context */ static void gen_topo_line (struct TopologyContext *tc) { unsigned int cnt; tc->link_array_size = tc->num_peers - 1; tc->link_array = GNUNET_malloc (sizeof (struct OverlayLink) * tc->link_array_size); for (cnt = 0; cnt < (tc->num_peers - 1); cnt++) make_link (&tc->link_array[cnt], cnt, cnt + 1, tc); } /** * Generates ring topology * * @param tc the topology context */ static void gen_topo_ring (struct TopologyContext *tc) { gen_topo_line (tc); tc->link_array_size++; tc->link_array = GNUNET_realloc (tc->link_array, sizeof (struct OverlayLink) * tc->link_array_size); make_link (&tc->link_array[tc->link_array_size - 1], tc->num_peers - 1, 0, tc); } /** * Returns the number of links that are required to generate a 2d torus for the * given number of peers. Also returns the arrangment (number of rows and the * length of each row) * * @param num_peers number of peers * @param rows number of rows in the 2d torus. Can be NULL * @param rows_len the length of each row. This array will be allocated * fresh. The caller should free it. Can be NULL * @return the number of links that are required to generate a 2d torus for the * given number of peers */ unsigned int GNUNET_TESTBED_2dtorus_calc_links (unsigned int num_peers, unsigned int *rows, unsigned int **rows_len) { double sq; unsigned int sq_floor; unsigned int _rows; unsigned int *_rows_len; unsigned int x; unsigned int y; unsigned int _num_peers; unsigned int cnt; sq = sqrt (num_peers); sq = floor (sq); sq_floor = (unsigned int) sq; _rows = (sq_floor + 1); _rows_len = GNUNET_malloc (sizeof (unsigned int) * _rows); for (y = 0; y < _rows - 1; y++) _rows_len[y] = sq_floor; _num_peers = sq_floor * sq_floor; cnt = (_num_peers < 2) ? _num_peers : 2 * _num_peers; x = 0; y = 0; while (_num_peers < num_peers) { if (x < y) _rows_len[_rows - 1] = ++x; else _rows_len[y++]++; _num_peers++; } cnt += (x < 2) ? x : 2 * x; cnt += (y < 2) ? y : 2 * y; if (0 == _rows_len[_rows - 1]) _rows--; if (NULL != rows) *rows = _rows; if (NULL != rows_len) *rows_len = _rows_len; else GNUNET_free (_rows_len); return cnt; } /** * Generates ring topology * * @param tc the topology context */ static void gen_topo_2dtorus (struct TopologyContext *tc) { unsigned int rows; unsigned int *rows_len; unsigned int x; unsigned int y; unsigned int cnt; unsigned int offset; tc->link_array_size = GNUNET_TESTBED_2dtorus_calc_links (tc->num_peers, &rows, &rows_len); tc->link_array = GNUNET_malloc (sizeof (struct OverlayLink) * tc->link_array_size); cnt = 0; offset = 0; for (y = 0; y < rows; y++) { for (x = 0; x < rows_len[y] - 1; x++) { make_link (&tc->link_array[cnt], offset + x, offset + x + 1, tc); cnt++; } if (0 == x) break; make_link (&tc->link_array[cnt], offset + x, offset, tc); cnt++; offset += rows_len[y]; } for (x = 0; x < rows_len[0]; x++) { offset = 0; for (y = 0; y < rows - 1; y++) { if (x >= rows_len[y + 1]) break; GNUNET_assert (x < rows_len[y + 1]); make_link (&tc->link_array[cnt], offset + x, offset + rows_len[y] + x, tc); offset += rows_len[y]; cnt++; } if (0 == offset) break; make_link (&tc->link_array[cnt], offset + x, x, tc); cnt++; } GNUNET_assert (cnt == tc->link_array_size); GNUNET_free (rows_len); } /** * Generates ring topology * * @param tc the topology context * @param links the number of random links to establish * @param append GNUNET_YES to add links to existing link array; GNUNET_NO to * create a new link array */ static void gen_topo_random (struct TopologyContext *tc, unsigned int links, int append) { unsigned int cnt; unsigned int index; uint32_t A_rand; uint32_t B_rand; if (GNUNET_YES == append) { GNUNET_assert ((0 < tc->link_array_size) && (NULL != tc->link_array)); index = tc->link_array_size; tc->link_array_size += links; tc->link_array = GNUNET_realloc (tc->link_array, sizeof (struct OverlayLink) * tc->link_array_size); } else { GNUNET_assert ((0 == tc->link_array_size) && (NULL == tc->link_array)); index = 0; tc->link_array_size = links; tc->link_array = GNUNET_malloc (sizeof (struct OverlayLink) * tc->link_array_size); } for (cnt = 0; cnt < links; cnt++) { do { A_rand = GNUNET_CRYPTO_random_u32 (GNUNET_CRYPTO_QUALITY_WEAK, tc->num_peers); B_rand = GNUNET_CRYPTO_random_u32 (GNUNET_CRYPTO_QUALITY_WEAK, tc->num_peers); } while (A_rand == B_rand); make_link (&tc->link_array[index + cnt], A_rand, B_rand, tc); } } /** * Generates scale free network. Its construction is described in: * * "Emergence of Scaling in Random Networks." Science 286, 509-512, 1999. * * @param tc the topology context */ static void gen_scale_free (struct TopologyContext *tc) { double random; double probability; unsigned int cnt; unsigned int previous_connections; unsigned int i; uint16_t *popularity; popularity = GNUNET_malloc (sizeof (uint16_t) * tc->num_peers); /* Initially connect peer 1 to peer 0 */ tc->link_array_size = 1; tc->link_array = GNUNET_malloc (sizeof (struct OverlayLink)); make_link (&tc->link_array[0], 0, 1, tc); popularity[0]++; /* increase popularity of 0 as 1 connected to it */ for (cnt = 1; cnt < tc->num_peers; cnt++) { previous_connections = tc->link_array_size; for (i = 0; i < cnt; i++) { probability = ((double) popularity[i]) / ((double) previous_connections); random = ((double) GNUNET_CRYPTO_random_u64 (GNUNET_CRYPTO_QUALITY_WEAK, UINT64_MAX)) / ((double) UINT64_MAX); if (random < probability) { tc->link_array_size++; tc->link_array = GNUNET_realloc (tc->link_array, (sizeof (struct OverlayLink) * tc->link_array_size)); make_link (&tc->link_array[tc->link_array_size - 1], cnt, i, tc); popularity[cnt]++; } } } GNUNET_free (popularity); } /** * Generates topology from the given file * * @param tc the topology context * @param filename the filename of the file containing topology data */ static void gen_topo_from_file (struct TopologyContext *tc, const char *filename) { char *data; char *end; char *buf; uint64_t fs; uint64_t offset; unsigned long int peer_id; unsigned long int other_peer_id; enum ParseState { /** * We read the peer index */ PEER_INDEX, /** * We read the other peer indices */ OTHER_PEER_INDEX, } state; int status; status = GNUNET_SYSERR; if (GNUNET_YES != GNUNET_DISK_file_test (filename)) { LOG (GNUNET_ERROR_TYPE_ERROR, _("Topology file %s not found\n"), filename); return; } if (GNUNET_OK != GNUNET_DISK_file_size (filename, &fs, GNUNET_YES, GNUNET_YES)) { LOG (GNUNET_ERROR_TYPE_ERROR, _("Topology file %s has no data\n"), filename); return; } data = GNUNET_malloc (fs); if (fs != GNUNET_DISK_fn_read (filename, data, fs)) { LOG (GNUNET_ERROR_TYPE_ERROR, _("Topology file %s cannot be read\n"), filename); goto _exit; } offset = 0; peer_id = 0; state = PEER_INDEX; buf = data; while (offset < fs) { if (0 != isspace (data[offset])) { offset++; continue; } switch (state) { case PEER_INDEX: buf = strchr (&data[offset], ':'); if (NULL == buf) { LOG (GNUNET_ERROR_TYPE_ERROR, _("Failed to read peer index from toology file: %s"), filename); goto _exit; } *buf = '\0'; errno = 0; peer_id = (unsigned int) strtoul (&data[offset], &end, 10); if (0 != errno) { LOG (GNUNET_ERROR_TYPE_ERROR, _("Value in given topology file: %s out of range\n"), filename); goto _exit; } if (&data[offset] == end) { LOG (GNUNET_ERROR_TYPE_ERROR, _("Failed to read peer index from topology file: %s"), filename); goto _exit; } if (tc->num_peers <= peer_id) { LOG (GNUNET_ERROR_TYPE_ERROR, _("Topology file needs more peers than given ones\n"), filename); goto _exit; } state = OTHER_PEER_INDEX; offset += ((unsigned int) (buf - &data[offset])) + 1; break; case OTHER_PEER_INDEX: errno = 0; other_peer_id = (unsigned int) strtoul (&data[offset], &end, 10); if (0 != errno) { LOG (GNUNET_ERROR_TYPE_ERROR, _("Value in given topology file: %s out of range\n"), filename); goto _exit; } if (&data[offset] == end) { LOG (GNUNET_ERROR_TYPE_ERROR, _("Failed to read peer index from topology file: %s"), filename); goto _exit; } if (tc->num_peers <= other_peer_id) { LOG (GNUNET_ERROR_TYPE_ERROR, _("Topology file needs more peers than given ones\n"), filename); goto _exit; } if (peer_id != other_peer_id) { tc->link_array_size++; tc->link_array = GNUNET_realloc (tc->link_array, sizeof (struct OverlayLink) * tc->link_array_size); offset += end - &data[offset]; make_link (&tc->link_array[tc->link_array_size - 1], peer_id, other_peer_id, tc); } else LOG (GNUNET_ERROR_TYPE_WARNING, _("Ignoring to connect peer %u to peer %u\n"), peer_id, other_peer_id); while (('\n' != data[offset]) && ('|' != data[offset]) && (offset < fs)) offset++; if ('\n' == data[offset]) state = PEER_INDEX; else if ('|' == data[offset]) { state = OTHER_PEER_INDEX; offset++; } break; } } status = GNUNET_OK; _exit: GNUNET_free (data); if (GNUNET_OK != status) { LOG (GNUNET_ERROR_TYPE_WARNING, "Removing link data read from the file\n"); tc->link_array_size = 0; GNUNET_free_non_null (tc->link_array); tc->link_array = NULL; } } /** * Configure overall network topology to have a particular shape. * * @param op_cls closure argument to give with the operation event * @param num_peers number of peers in 'peers' * @param peers array of 'num_peers' with the peers to configure * @param topo desired underlay topology to use * @param ap topology-specific options * @return handle to the operation, NULL if configuring the topology * is not allowed at this time */ struct GNUNET_TESTBED_Operation * GNUNET_TESTBED_underlay_configure_topology_va (void *op_cls, unsigned int num_peers, struct GNUNET_TESTBED_Peer **peers, enum GNUNET_TESTBED_TopologyOption topo, va_list ap) { GNUNET_break (0); return NULL; } /** * Configure overall network topology to have a particular shape. * * @param op_cls closure argument to give with the operation event * @param num_peers number of peers in 'peers' * @param peers array of 'num_peers' with the peers to configure * @param topo desired underlay topology to use * @param ... topology-specific options * @return handle to the operation, NULL if configuring the topology * is not allowed at this time */ struct GNUNET_TESTBED_Operation * GNUNET_TESTBED_underlay_configure_topology (void *op_cls, unsigned int num_peers, struct GNUNET_TESTBED_Peer **peers, enum GNUNET_TESTBED_TopologyOption topo, ...) { GNUNET_break (0); return NULL; } /** * All peers must have been started before calling this function. * This function then connects the given peers in the P2P overlay * using the given topology. * * @param op_cls closure argument to give with the peer connect operation events * generated through this function * @param num_peers number of peers in 'peers' * @param peers array of 'num_peers' with the peers to configure * @param max_connections the maximums number of overlay connections that will * be made to achieve the given topology * @param comp_cb the completion callback to call when the topology generation * is completed * @param comp_cb_cls closure for the above completion callback * @param topo desired underlay topology to use * @param va topology-specific options * @return handle to the operation, NULL if connecting these * peers is fundamentally not possible at this time (peers * not running or underlay disallows) or if num_peers is less than 2 */ struct GNUNET_TESTBED_Operation * GNUNET_TESTBED_overlay_configure_topology_va (void *op_cls, unsigned int num_peers, struct GNUNET_TESTBED_Peer **peers, unsigned int *max_connections, GNUNET_TESTBED_TopologyCompletionCallback comp_cb, void *comp_cb_cls, enum GNUNET_TESTBED_TopologyOption topo, va_list va) { struct TopologyContext *tc; struct GNUNET_TESTBED_Operation *op; struct GNUNET_TESTBED_Controller *c; enum GNUNET_TESTBED_TopologyOption secondary_option; unsigned int cnt; if (num_peers < 2) return NULL; c = peers[0]->controller; tc = GNUNET_malloc (sizeof (struct TopologyContext)); tc->peers = peers; tc->num_peers = num_peers; tc->op_cls = op_cls; tc->retry_cnt = DEFAULT_RETRY_CNT; tc->comp_cb = comp_cb; tc->comp_cb_cls = comp_cb_cls; switch (topo) { case GNUNET_TESTBED_TOPOLOGY_LINE: gen_topo_line (tc); break; case GNUNET_TESTBED_TOPOLOGY_RING: gen_topo_ring (tc); break; case GNUNET_TESTBED_TOPOLOGY_ERDOS_RENYI: gen_topo_random (tc, va_arg (va, unsigned int), GNUNET_NO); break; case GNUNET_TESTBED_TOPOLOGY_SMALL_WORLD_RING: gen_topo_ring (tc); gen_topo_random (tc, va_arg (va, unsigned int), GNUNET_YES); break; case GNUNET_TESTBED_TOPOLOGY_CLIQUE: tc->link_array_size = num_peers * (num_peers - 1); tc->link_array = GNUNET_malloc (sizeof (struct OverlayLink) * tc->link_array_size); { unsigned int offset; offset = 0; for (cnt = 0; cnt < num_peers; cnt++) { unsigned int neighbour; for (neighbour = 0; neighbour < num_peers; neighbour++) { if (neighbour == cnt) continue; tc->link_array[offset].A = cnt; tc->link_array[offset].B = neighbour; tc->link_array[offset].tc = tc; offset++; } } } break; case GNUNET_TESTBED_TOPOLOGY_2D_TORUS: gen_topo_2dtorus (tc); break; case GNUNET_TESTBED_TOPOLOGY_SMALL_WORLD: gen_topo_2dtorus (tc); gen_topo_random (tc, va_arg (va, unsigned int), GNUNET_YES); break; case GNUNET_TESTBED_TOPOLOGY_SCALE_FREE: gen_scale_free (tc); break; case GNUNET_TESTBED_TOPOLOGY_FROM_FILE: { const char *filename; filename = va_arg (va, const char *); GNUNET_assert (NULL != filename); gen_topo_from_file (tc, filename); } break; default: GNUNET_break (0); GNUNET_free (tc); return NULL; } do { secondary_option = va_arg (va, enum GNUNET_TESTBED_TopologyOption); switch (secondary_option) { case GNUNET_TESTBED_TOPOLOGY_RETRY_CNT: tc->retry_cnt = va_arg (va, unsigned int); break; case GNUNET_TESTBED_TOPOLOGY_OPTION_END: break; default: GNUNET_break (0); /* Should not use any other option apart from * the ones handled here */ GNUNET_free_non_null (tc->link_array); GNUNET_free (tc); return NULL; } } while (GNUNET_TESTBED_TOPOLOGY_OPTION_END != secondary_option); op = GNUNET_TESTBED_operation_create_ (tc, &opstart_overlay_configure_topology, &oprelease_overlay_configure_topology); GNUNET_TESTBED_operation_queue_insert_ (c->opq_parallel_topology_config_operations, op); GNUNET_TESTBED_operation_begin_wait_ (op); LOG (GNUNET_ERROR_TYPE_DEBUG, "Generated %u connections\n", tc->link_array_size); if (NULL != max_connections) *max_connections = tc->link_array_size; return op; } /** * All peers must have been started before calling this function. * This function then connects the given peers in the P2P overlay * using the given topology. * * @param op_cls closure argument to give with the peer connect operation events * generated through this function * @param num_peers number of peers in 'peers' * @param peers array of 'num_peers' with the peers to configure * @param max_connections the maximums number of overlay connections that will * be made to achieve the given topology * @param comp_cb the completion callback to call when the topology generation * is completed * @param comp_cb_cls closure for the above completion callback * @param topo desired underlay topology to use * @param ... topology-specific options * @return handle to the operation, NULL if connecting these * peers is fundamentally not possible at this time (peers * not running or underlay disallows) or if num_peers is less than 2 */ struct GNUNET_TESTBED_Operation * GNUNET_TESTBED_overlay_configure_topology (void *op_cls, unsigned int num_peers, struct GNUNET_TESTBED_Peer **peers, unsigned int *max_connections, GNUNET_TESTBED_TopologyCompletionCallback comp_cb, void *comp_cb_cls, enum GNUNET_TESTBED_TopologyOption topo, ...) { struct GNUNET_TESTBED_Operation *op; va_list vargs; GNUNET_assert (topo < GNUNET_TESTBED_TOPOLOGY_OPTION_END); va_start (vargs, topo); op = GNUNET_TESTBED_overlay_configure_topology_va (op_cls, num_peers, peers, max_connections, comp_cb, comp_cb_cls, topo, vargs); va_end (vargs); return op; } /** * Get a topology from a string input. * * @param topology where to write the retrieved topology * @param topology_string The string to attempt to * get a configuration value from * @return GNUNET_YES if topology string matched a * known topology, GNUNET_NO if not */ int GNUNET_TESTBED_topology_get_ (enum GNUNET_TESTBED_TopologyOption *topology, const char *topology_string) { unsigned int cnt; for (cnt = 0; NULL != topology_strings[cnt]; cnt++) { if (0 == strcasecmp (topology_string, topology_strings[cnt])) { if (NULL != topology) *topology = (enum GNUNET_TESTBED_TopologyOption) cnt; return GNUNET_YES; } } return GNUNET_NO; } /** * Returns the string corresponding to the given topology * * @param topology the topology * @return the string (freshly allocated) of given topology; NULL if topology cannot be * expressed as a string */ char * GNUNET_TESTBED_topology_to_str_ (enum GNUNET_TESTBED_TopologyOption topology) { if (GNUNET_TESTBED_TOPOLOGY_OPTION_END <= topology) return NULL; return GNUNET_strdup (topology_strings[topology]); } /* end of testbed_api_topology.c */