/* * Copyright (c) 2016, FreeSWITCH * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * * Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * * * Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * * Neither the name of the original author; nor the names of any contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ #pragma GCC optimize ("O0") #include "ks_dht.h" /* change for testing */ #define KS_DHT_BUCKETSIZE 20 #define KS_DHTRT_INACTIVETIME (5*60) #define KS_DHTRT_MAXPING 3 /* peer flags */ #define DHTPEER_ACTIVE 1 #define DHTPEER_SUSPECT 2 #define DHTPEER_EXPIRED 3 typedef uint8_t ks_dhtrt_nodeid_t[KS_DHT_NODEID_SIZE]; /* internal structures */ typedef struct ks_dhtrt_bucket_entry_s { ks_time_t tyme; uint8_t id[KS_DHT_NODEID_SIZE]; ks_dht_node_t* gptr; /* ptr to peer */ uint8_t inuse; uint8_t outstanding_pings; uint8_t flags; /* active, suspect, expired */ } ks_dhtrt_bucket_entry_t; typedef struct ks_dhtrt_bucket_s { ks_dhtrt_bucket_entry_t entries[KS_DHT_BUCKETSIZE]; uint8_t count; uint8_t expired_count; ks_rwl_t* lock; uint8_t locked; } ks_dhtrt_bucket_t; #define BHF_LEFT 0x80 typedef struct ks_dhtrt_bucket_header_s { struct ks_dhtrt_bucket_header_s* parent; struct ks_dhtrt_bucket_header_s* left; struct ks_dhtrt_bucket_header_s* right; ks_dhtrt_bucket_t* bucket; ks_time_t tyme; /* last processed time */ unsigned char mask[KS_DHT_NODEID_SIZE]; /* node id mask */ unsigned char flags; } ks_dhtrt_bucket_header_t; typedef struct ks_dhtrt_internal_s { uint8_t localid[KS_DHT_NODEID_SIZE]; ks_dhtrt_bucket_header_t* buckets; /* root bucketheader */ ks_rwl_t* lock; /* lock for safe traversal of the tree */ uint8_t locked; } ks_dhtrt_internal_t; typedef struct ks_dhtrt_xort_s { unsigned int ix; /* index of bucket array */ unsigned char xor[KS_DHT_NODEID_SIZE]; /* corresponding xor value */ unsigned int nextix; } ks_dhtrt_xort_t; typedef struct ks_dhtrt_sortedxors_s { ks_dhtrt_bucket_header_t* bheader; ks_dhtrt_xort_t xort[KS_DHT_BUCKETSIZE]; unsigned char hixor[KS_DHT_NODEID_SIZE]; unsigned int startix; unsigned int count; struct ks_dhtrt_sortedxors_s* next; } ks_dhtrt_sortedxors_t; /* --- static functions ---- */ static ks_dhtrt_bucket_header_t* ks_dhtrt_create_bucketheader( ks_pool_t *pool, ks_dhtrt_bucket_header_t* parent, unsigned char* mask); static ks_dhtrt_bucket_t* ks_dhtrt_create_bucket(ks_pool_t* pool); static ks_dhtrt_bucket_header_t* ks_dhtrt_find_bucketheader(ks_dhtrt_routetable_t* table, ks_dhtrt_nodeid_t id); static ks_dhtrt_bucket_entry_t* ks_dhtrt_find_bucketentry(ks_dhtrt_bucket_header_t* header, ks_dhtrt_nodeid_t id); static void ks_dhtrt_split_bucket(ks_dhtrt_bucket_header_t* original, ks_dhtrt_bucket_header_t* left, ks_dhtrt_bucket_header_t* right); static ks_dht_node_t* ks_dhtrt_find_nodeid(ks_dhtrt_bucket_t* bucket, ks_dhtrt_nodeid_t nodeid); static void ks_dhtrt_shiftright(uint8_t* id); static void ks_dhtrt_shiftleft(uint8_t* id); static void ks_dhtrt_xor(const uint8_t* id1, const uint8_t* id2, uint8_t* xor); static int ks_dhtrt_ismasked(const uint8_t* id1, const uint8_t* mask); static ks_status_t ks_dhtrt_insert_node(ks_dhtrt_routetable_t* table, ks_dht_node_t* node); static ks_status_t ks_dhtrt_insert_id(ks_dhtrt_bucket_t* bucket, ks_dht_node_t* node); static void ks_dhtrt_delete_id(ks_dhtrt_bucket_t* bucket, ks_dhtrt_nodeid_t id); static char* ks_dhtrt_printableid(uint8_t* id, char* buffer); static unsigned char ks_dhtrt_isactive(ks_dhtrt_bucket_entry_t* entry); static uint8_t ks_dhtrt_load_query(ks_dhtrt_querynodes_t* query, ks_dhtrt_sortedxors_t* xort); static uint8_t ks_dhtrt_findclosest_bucketnodes(unsigned char *nodeid, ks_dhtrt_bucket_header_t* header, ks_dhtrt_sortedxors_t* xors, unsigned char* hixor, unsigned int max); static void ks_dhtrt_ping(ks_dhtrt_bucket_entry_t* entry); /* debugging */ #define KS_DHT_DEBUGPRINTF_ /* # define KS_DHT_DEBUGPRINTFX_ very verbose */ /* Public interface --------------- ks_dhtrt_initroute ks_dhtrt_drinitroute ks_dhtrt_insertnode */ KS_DECLARE(ks_dhtrt_routetable_t*) ks_dhtrt_initroute( ks_pool_t *pool, ks_dht_nodeid_t nodeid) { unsigned char initmask[KS_DHT_NODEID_SIZE]; memset(initmask, 0xff, sizeof(initmask)); ks_dhtrt_routetable_t* table = ks_pool_alloc(pool, sizeof(ks_dhtrt_routetable_t)); memset(table, 0, sizeof(ks_dhtrt_routetable_t)); ks_dhtrt_internal_t* internal = ks_pool_alloc(pool, sizeof(ks_dhtrt_internal_t)); memset(internal, 0, sizeof(ks_dhtrt_internal_t)); /*ks_rwl_create(&internal->lock, pool);*/ if (nodeid.id != 0) memcpy(internal->localid, nodeid.id, KS_DHT_NODEID_SIZE); table->internal = internal; /* initialize root bucket */ ks_dhtrt_bucket_header_t* initial_header = ks_dhtrt_create_bucketheader(pool, 0, initmask); initial_header->flags = BHF_LEFT; /* fake left to allow splitting */ internal->buckets = initial_header; initial_header->bucket = ks_dhtrt_create_bucket(pool); table->pool = pool; return table; } KS_DECLARE(void) ks_dhtrt_deinitroute( ks_dhtrt_routetable_t* table ) { /* @todo*/ ks_pool_free(table->pool, table); return; } KS_DECLARE(ks_status_t) ks_dhtrt_create_node( ks_dhtrt_routetable_t* table, ks_dht_nodeid_t nodeid, char* ip, unsigned short port, ks_dht_node_t** node) { ks_dht_node_t* tnode = ks_dhtrt_find_node(table, nodeid); if (tnode != 0) return KS_STATUS_FAIL; /* protect against duplicates */ /* @todo - replace with reusable memory pool */ tnode = ks_pool_alloc(table->pool, sizeof(ks_dht_node_t)); tnode->table = table; for(int i=0; i<5; ++i) { if (ip[i] == ':') { tnode->family = AF_INET6; break;} else if (ip[i] == '.') { tnode->family = AF_INET; break; } } memcpy(tnode->nodeid.id, nodeid.id, KS_DHT_NODEID_SIZE); if ( (ks_addr_set(&tnode->addr, ip, port, tnode->family) != KS_STATUS_SUCCESS) || (ks_dhtrt_insert_node(table, tnode) != KS_STATUS_SUCCESS) ) { ks_pool_free(table->pool, tnode); return KS_STATUS_FAIL; } (*node) = tnode; return KS_STATUS_SUCCESS; } KS_DECLARE(ks_status_t) ks_dhtrt_delete_node(ks_dhtrt_routetable_t* table, ks_dht_node_t* node) { ks_dhtrt_bucket_header_t* header = ks_dhtrt_find_bucketheader(table, node->nodeid.id); if (header != 0) { ks_dhtrt_bucket_t* bucket = header->bucket; if (bucket != 0) { /* we were not able to find a bucket*/ ks_dhtrt_delete_id(bucket, node->nodeid.id); } } ks_pool_free(table->pool, node); return KS_STATUS_SUCCESS; } static ks_status_t ks_dhtrt_insert_node(ks_dhtrt_routetable_t* table, ks_dht_node_t* node) { ks_dhtrt_bucket_t* bucket = 0; int insanity = 0; /* first see if it exists */ ks_dht_node_t* peer = ks_dhtrt_find_node(table, node->nodeid); if (peer != 0) { return KS_STATUS_FAIL; } ks_dhtrt_bucket_header_t* header = ks_dhtrt_find_bucketheader(table, node->nodeid.id); bucket = header->bucket; assert(bucket != 0); /* we were not able to find a bucket*/ while (bucket->count == KS_DHT_BUCKETSIZE) { if (insanity > 3200) assert(insanity < 3200); /* first - seek a stale entry to eject */ if (bucket->expired_count) { ks_status_t s = ks_dhtrt_insert_id(bucket, node); if (s == KS_STATUS_SUCCESS) return KS_STATUS_SUCCESS; } /* todo: attempting a ping at at this point would require us to suspend this process ... tricky...assume right now we will go ahead and eject. Possibly add to a list to recheck */ if ( !(header->flags & BHF_LEFT) ) { /* only the left handside node can be split */ #ifdef KS_DHT_DEBUGPRINTF_ char buffer[100]; printf(" nodeid %s was not inserted\n", ks_dhtrt_printableid(node->nodeid.id, buffer)); #endif return KS_STATUS_FAIL; } /* bucket must be split */ /* work out new mask */ unsigned char newmask[KS_DHT_NODEID_SIZE]; memcpy(newmask, header->mask, KS_DHT_NODEID_SIZE); if (newmask[KS_DHT_NODEID_SIZE-1] == 0) { /* no more bits to shift - is this possible */ #ifdef KS_DHT_DEBUGPRINTF_ char buffer[100]; printf(" nodeid %s was not inserted\n", ks_dhtrt_printableid(peer->nodeid.id, buffer)); #endif return KS_STATUS_FAIL; } /* shift right x bits : todo 1 bit for the moment */ ks_dhtrt_shiftright(newmask); /* create the new bucket structures */ ks_dhtrt_bucket_header_t* newleft = ks_dhtrt_create_bucketheader(table->pool, header, newmask); newleft->bucket = ks_dhtrt_create_bucket(table->pool); newleft->flags = BHF_LEFT; /* flag as left hand side - therefore splitable */ ks_dhtrt_bucket_header_t* newright = ks_dhtrt_create_bucketheader(table->pool, header, header->mask); ks_dhtrt_split_bucket(header, newleft, newright); /* ok now we need to try again to see if the bucket has capacity */ /* which bucket do care about */ if (ks_dhtrt_ismasked(node->nodeid.id, newleft->mask)) { bucket = newleft->bucket; header = newleft; } else { bucket = newright->bucket; header = newright; } ++insanity; } #ifdef KS_DHT_DEBUGPRINTF_ char buffer[100]; printf("inserting nodeid %s ", ks_dhtrt_printableid(node->nodeid.id, buffer)); printf("into bucket %s\n", ks_dhtrt_printableid(header->mask, buffer)); #endif /* by this point we have a viable bucket */ return ks_dhtrt_insert_id(bucket, node); } KS_DECLARE(ks_dht_node_t*) ks_dhtrt_find_node(ks_dhtrt_routetable_t* table, ks_dht_nodeid_t nodeid) { ks_dhtrt_bucket_header_t* header = ks_dhtrt_find_bucketheader(table, nodeid.id); if (header == 0) return 0; ks_dhtrt_bucket_t* bucket = header->bucket; if (bucket == 0) return 0; /* probably a logic error ?*/ return ks_dhtrt_find_nodeid(bucket, nodeid.id); } KS_DECLARE(ks_status_t) ks_dhtrt_touch_node(ks_dhtrt_routetable_t* table, ks_dht_nodeid_t nodeid) { ks_dhtrt_bucket_header_t* header = ks_dhtrt_find_bucketheader(table, nodeid.id); if (header == 0) return KS_STATUS_FAIL; if (header->bucket == 0) return KS_STATUS_FAIL; ks_dhtrt_bucket_entry_t* e = ks_dhtrt_find_bucketentry(header, nodeid.id); if (e != 0) { e->tyme = ks_time_now(); e->outstanding_pings = 0; if (e->flags == DHTPEER_EXPIRED) --header->bucket->expired_count; e->flags = DHTPEER_ACTIVE; return KS_STATUS_SUCCESS; } return KS_STATUS_FAIL; } KS_DECLARE(ks_status_t) ks_dhtrt_expire_node(ks_dhtrt_routetable_t* table, ks_dht_nodeid_t nodeid) { ks_dhtrt_bucket_header_t* header = ks_dhtrt_find_bucketheader(table, nodeid.id); if (header == 0) return KS_STATUS_FAIL; ks_dhtrt_bucket_entry_t* e = ks_dhtrt_find_bucketentry(header, nodeid.id); if (e != 0) { e->flags = DHTPEER_EXPIRED; return KS_STATUS_SUCCESS; } return KS_STATUS_FAIL; } KS_DECLARE(uint8_t) ks_dhtrt_findclosest_nodes(ks_dhtrt_routetable_t* table, ks_dhtrt_querynodes_t* query) { query->count = 0; uint8_t max = query->max; uint8_t total = 0; uint8_t cnt; if (max == 0) return 0; /* sanity check */ ks_dhtrt_bucket_header_t* header = ks_dhtrt_find_bucketheader(table, query->nodeid.id); #ifdef KS_DHT_DEBUGPRINTF_ char buffer[100]; printf("finding %d closest nodes for nodeid %s\n", max, ks_dhtrt_printableid(query->nodeid.id, buffer)); printf(" starting at mask: %s\n", ks_dhtrt_printableid(header->mask, buffer)); #endif ks_dhtrt_sortedxors_t xort0; memset(&xort0, 0 , sizeof(xort0)); ks_dhtrt_nodeid_t initid; memset(initid, 0xff, KS_DHT_NODEID_SIZE); xort0.bheader = header; /* step 1 - look at immediate bucket */ /* --------------------------------- */ cnt = ks_dhtrt_findclosest_bucketnodes(query->nodeid.id, header, &xort0, initid ,max); max -= cnt; total += cnt; #ifdef KS_DHT_DEBUGPRINTF_ printf(" bucket header %s yielded %d nodes; total=%d\n", buffer, cnt, total); #endif if (total >= query->max) { /* is query answered ? */ return ks_dhtrt_load_query(query, &xort0); } /* step2 - look at sibling */ /* ----------------------- */ ks_dhtrt_sortedxors_t xort1; xort0.next = &xort1; memset(&xort1, 0 , sizeof(xort1)); memcpy(initid, &xort0.hixor, KS_DHT_NODEID_SIZE); ks_dhtrt_bucket_header_t* parent = header->parent; if (header == parent->left) { xort1.bheader = header = parent->right; } else { if (!parent->left->bucket) { /* left hand might no have a bucket - if so choose left->right */ xort1.bheader = header = parent->left->right; } else { xort1.bheader = header = parent->left; } } cnt = ks_dhtrt_findclosest_bucketnodes(query->nodeid.id, header, &xort1, initid ,max); max -= cnt; total += cnt; #ifdef KS_DHT_DEBUGPRINTF_ printf(" stage2: sibling bucket header %s yielded %d nodes, total=%d\n", ks_dhtrt_printableid(header->mask, buffer), cnt, total); #endif if (total >= query->max) { /* is query answered ? */ return ks_dhtrt_load_query(query, &xort0); } /* step3 and beyond ... work left and right until the count is satisfied */ /* ---------------------------------------------------------------------- */ memcpy(initid, &xort0.hixor, KS_DHT_NODEID_SIZE); unsigned char leftid[KS_DHT_NODEID_SIZE]; unsigned char rightid[KS_DHT_NODEID_SIZE]; memcpy(leftid, xort0.bheader->mask, KS_DHT_NODEID_SIZE); memcpy(rightid, xort1.bheader->mask, KS_DHT_NODEID_SIZE); int insanity = 0; ks_dhtrt_bucket_header_t* lheader; ks_dhtrt_bucket_header_t* rheader; ks_dhtrt_sortedxors_t* prev = &xort1; ks_dhtrt_sortedxors_t* tofree = 0; ks_dhtrt_sortedxors_t* xortn; ks_dhtrt_sortedxors_t* xortn1; do { lheader = 0; rheader = 0; xortn = 0; xortn1 = 0; if (leftid[0] != 0xff) { ks_dhtrt_shiftleft(leftid); lheader = ks_dhtrt_find_bucketheader(table, leftid); if (lheader) { xortn = ks_pool_alloc(table->pool, sizeof(ks_dhtrt_sortedxors_t)); memset(xortn, 0, sizeof(ks_dhtrt_sortedxors_t)); if (tofree == 0) tofree = xortn; prev->next = xortn; prev = xortn; cnt += ks_dhtrt_findclosest_bucketnodes(query->nodeid.id, lheader, xortn, leftid ,max); max -= cnt; #ifdef KS_DHT_DEBUGPRINTF_ printf(" stage3: seaching left bucket header %s yielded %d nodes, total=%d\n", ks_dhtrt_printableid(lheader->mask, buffer), cnt, total); #endif } } if (max > 0 && rightid[KS_DHT_NODEID_SIZE-1] != 0x00) { ks_dhtrt_shiftright(rightid); rheader = ks_dhtrt_find_bucketheader(table, rightid); if (rheader) { xortn1 = ks_pool_alloc(table->pool, sizeof(ks_dhtrt_sortedxors_t)); memset(xortn1, 0, sizeof(ks_dhtrt_sortedxors_t)); prev->next = xortn1; prev = xortn1; cnt = ks_dhtrt_findclosest_bucketnodes(query->nodeid.id, rheader, xortn1, rightid , max); max -= cnt; #ifdef KS_DHT_DEBUGPRINTF_ printf(" stage3: seaching right bucket header %s yielded %d nodes, total=%d\n", ks_dhtrt_printableid(rheader->mask, buffer), cnt, total); #endif } } if (!lheader && !rheader) break; ++insanity; if (insanity > 159) { assert(insanity <= 159); } } while(max < query->count); ks_dhtrt_load_query(query, &xort0); /* free up the xort structs on heap */ while(tofree) { ks_dhtrt_sortedxors_t* x = tofree->next; ks_pool_free(table->pool, tofree); tofree = x->next; } return query->count; } KS_DECLARE(void) ks_dhtrt_process_table(ks_dhtrt_routetable_t* table) { /* walk the table and update the status of all known knodes */ /* anything that is suspect automatically becomes expired */ /* inactive for 15 minutes, a node becomes quesionable */ /* it should be pinged */ /* if it has not been 'touched' since the last time */ /* give it one more try */ /* inactive again it is considered inactive */ /* */ ks_dhtrt_internal_t* internal = table->internal; ks_dhtrt_bucket_header_t* header = internal->buckets; ks_dhtrt_bucket_header_t* stack[KS_DHT_NODEID_SIZE * 8]; int stackix=0; ks_time_t t0 = ks_time_now(); while(header) { stack[stackix++] = header; if (header->bucket) { ks_dhtrt_bucket_t* b = header->bucket; for (int ix=0; ixentries[ix]; if (e->inuse == 1) { /* more than n pings outstanding? */ if (e->outstanding_pings >= KS_DHTRT_MAXPING) { e->flags = DHTPEER_EXPIRED; ++b->expired_count; continue; } if (e->flags == DHTPEER_SUSPECT) { ks_dhtrt_ping(e); continue; } ks_time_t tdiff = t0 - e->tyme; if (tdiff > KS_DHTRT_INACTIVETIME) { e->flags = DHTPEER_SUSPECT; ks_dhtrt_ping(e); } } } /* end for each bucket_entry */ } header = header->left; if (header == 0 && stackix > 1) { stackix -= 2; header = stack[stackix]; header = header->right; } } return; } KS_DECLARE(void) ks_dhtrt_dump(ks_dhtrt_routetable_t* table, int level) { /* dump buffer headers */ char buffer[100]; memset(buffer, 0, 100); ks_dhtrt_internal_t* internal = table->internal; ks_dhtrt_bucket_header_t* header = internal->buckets; ks_dhtrt_bucket_header_t* stack[KS_DHT_NODEID_SIZE * 8]; int stackix = 0; while(header) { stack[stackix++] = header; /* walk and report left handsize */ memset(buffer, 0, 100); /*ks_log*/ printf("bucket header: [%s]\n", ks_dhtrt_printableid(header->mask, buffer) ); if (header->bucket) { ks_dhtrt_bucket_t* b = header->bucket; printf(" bucket holds %d entries\n", b->count); if (level == 7) { printf(" --------------------------\n"); for(int ix=0; ixentries[ix].inuse == 1) ks_dhtrt_printableid(b->entries[ix].id, buffer); else strcpy(buffer, ""); printf(" slot %d: %s\n", ix, buffer); } printf(" --------------------------\n\n"); } } header = header->left; if (header == 0 && stackix > 1) { stackix -= 2; header = stack[stackix]; header = header->right; } } return; } /* internal functions */ static ks_dhtrt_bucket_header_t* ks_dhtrt_create_bucketheader(ks_pool_t *pool, ks_dhtrt_bucket_header_t* parent, uint8_t* mask) { ks_dhtrt_bucket_header_t* header = ks_pool_alloc(pool, sizeof(ks_dhtrt_bucket_header_t)); memset(header, 0, sizeof(ks_dhtrt_bucket_header_t)); memcpy(header->mask, mask, sizeof(header->mask)); header->parent = parent; #ifdef KS_DHT_DEBUGPRINTF_ char buffer[100]; printf("creating bucket header for mask: %s ", ks_dhtrt_printableid(mask, buffer)); if (parent) printf("from parent mask: %s ", ks_dhtrt_printableid(parent->mask, buffer)); printf("\n"); #endif return header; } static ks_dhtrt_bucket_t* ks_dhtrt_create_bucket(ks_pool_t *pool) { ks_dhtrt_bucket_t* bucket = ks_pool_alloc(pool, sizeof(ks_dhtrt_bucket_t)); memset(bucket, 0, sizeof(ks_dhtrt_bucket_t)); /*ks_rwl_create(&bucket->lock, pool);*/ return bucket; } static ks_dhtrt_bucket_header_t* ks_dhtrt_find_bucketheader(ks_dhtrt_routetable_t* table, ks_dhtrt_nodeid_t id) { /* find the right bucket. if a bucket header has a bucket, it does not children so it must be the bucket to use */ ks_dhtrt_internal_t* internal = table->internal; ks_dhtrt_bucket_header_t* header = internal->buckets; while(header) { if ( header->bucket ) { return header; } /* left hand side is more restrictive (closer) so should be tried first */ if (header->left != 0 && (ks_dhtrt_ismasked(id, header->left->mask))) header = header->left; else header = header->right; } return 0; } static ks_dhtrt_bucket_entry_t* ks_dhtrt_find_bucketentry(ks_dhtrt_bucket_header_t* header, ks_dhtrt_nodeid_t nodeid) { ks_dhtrt_bucket_t* bucket = header->bucket; if (bucket == 0) return 0; for (int ix=0; ixentries[ix].inuse == 1 && (!memcmp(nodeid, bucket->entries[ix].id, KS_DHT_NODEID_SIZE)) ) { return &(bucket->entries[ix]); } } return 0; } static void ks_dhtrt_split_bucket(ks_dhtrt_bucket_header_t* original, ks_dhtrt_bucket_header_t* left, ks_dhtrt_bucket_header_t* right) { /* so split the bucket in two based on the masks in the new header */ /* the existing bucket - with the remaining ids will be taken by the right hand side */ ks_dhtrt_bucket_t* source = original->bucket; ks_dhtrt_bucket_t* dest = left->bucket; int lix = 0; int rix = 0; /* ****************** */ /* bucket write lock */ /* ****************** */ /*ks_rwl_write_lock(source->lock);*/ source->locked=1; for( ; rixentries[rix].id, left->mask)) { /* move it to the left */ memcpy(dest->entries[lix].id, source->entries[rix].id, KS_DHT_NODEID_SIZE); dest->entries[lix].gptr = source->entries[rix].gptr; dest->entries[lix].inuse = 1; ++lix; ++dest->count; /* now remove it from the original bucket */ source->entries[rix].inuse = 0; --source->count; } } /* *********************** */ /* end bucket write lock */ /* *********************** */ source->locked=0; /*ks_rwl_write_unlock(source->lock);*/ /* give original bucket to the new left hand side header */ right->bucket = source; original->bucket = 0; original->left = left; original->right = right; #ifdef KS_DHT_DEBUGPRINTF_ char buffer[100]; printf("\nsplitting bucket orginal: %s\n", ks_dhtrt_printableid(original->mask, buffer)); printf(" into (left) mask: %s size: %d\n", ks_dhtrt_printableid(left->mask, buffer), left->bucket->count); printf(" and (right) mask: %s size: %d\n\n", ks_dhtrt_printableid(right->mask, buffer), right->bucket->count); #endif return; } /* * buckets are implemented as static array * There does not seem to be any advantage in sorting/tree structures in terms of xor math * so at least the static array does away with the need for locking. */ static ks_status_t ks_dhtrt_insert_id(ks_dhtrt_bucket_t* bucket, ks_dht_node_t* node) { /* sanity checks */ if (!bucket || bucket->count >= KS_DHT_BUCKETSIZE) { assert(0); } uint8_t free = KS_DHT_BUCKETSIZE; uint8_t expiredix = KS_DHT_BUCKETSIZE; /* find free .. but also check that it is not already here! */ uint8_t ix = 0; for(; ixentries[ix].inuse == 0) { if (free == KS_DHT_BUCKETSIZE) { free = ix; /* use this one */ } } else if (free == KS_DHT_BUCKETSIZE && bucket->entries[ix].flags == DHTPEER_EXPIRED) { expiredix = ix; } else if (!memcmp(bucket->entries[ix].id, node->nodeid.id, KS_DHT_NODEID_SIZE)) { #ifdef KS_DHT_DEBUGPRINTF_ char buffer[100]; printf("duplicate peer %s found at %d ", ks_dhtrt_printableid(node->nodeid.id, buffer), ix); #endif bucket->entries[ix].tyme = ks_time_now(); bucket->entries[ix].flags &= DHTPEER_ACTIVE; return KS_STATUS_SUCCESS; /* already exists */ } } /* ****************** */ /* bucket write lock */ /* ****************** */ /*ks_rwl_write_lock(bucket->lock);*/ bucket->locked = 1; if (free == KS_DHT_BUCKETSIZE && expiredixexpired_count; } if ( freeentries[free].inuse = 1; bucket->entries[free].gptr = node; bucket->entries[free].tyme = ks_time_now(); bucket->entries[free].flags &= DHTPEER_ACTIVE; ++bucket->count; memcpy(bucket->entries[free].id, node->nodeid.id, KS_DHT_NODEID_SIZE); bucket->locked = 0; /*ks_rwl_write_unlock(bucket->lock);*/ #ifdef KS_DHT_DEBUGPRINTF_ char buffer[100]; printf("Inserting node %s\n", ks_dhtrt_printableid(node->nodeid.id, buffer)); #endif return KS_STATUS_SUCCESS; } bucket->locked = 0; /*ks_rwl_write_unlock(bucket->lock);*/ /* ********************** */ /* end bucket write lock */ /* ********************** */ return KS_STATUS_FAIL; } static ks_dht_node_t* ks_dhtrt_find_nodeid(ks_dhtrt_bucket_t* bucket, ks_dhtrt_nodeid_t id) { #ifdef KS_DHT_DEBUGPRINTF_ char buffer[100]; printf("find nodeid for: %s\n", ks_dhtrt_printableid(id, buffer)); #endif for (int ix=0; ixentries[ix].inuse == 1) { printf("\nbucket->entries[%d].id = %s inuse=%x\n", ix, ks_dhtrt_printableid(bucket->entries[ix].id, bufferx), bucket->entries[ix].inuse ); } #endif if ( bucket->entries[ix].inuse == 1 && (!memcmp(id, bucket->entries[ix].id, KS_DHT_NODEID_SIZE)) ) { return bucket->entries[ix].gptr; } } return 0; } static void ks_dhtrt_delete_id(ks_dhtrt_bucket_t* bucket, ks_dhtrt_nodeid_t id) { #ifdef KS_DHT_DEBUGPRINTF_ char buffer[100]; printf("\ndeleting node for: %s\n", ks_dhtrt_printableid(id, buffer)); #endif for (int ix=0; ixentries[%d].id = %s inuse=%c\n", ix, ks_dhtrt_printableid(bucket->entries[ix].id, buffer), bucket->entries[ix].inuse ); #endif if ( bucket->entries[ix].inuse == 1 && (!memcmp(id, bucket->entries[ix].id, KS_DHT_NODEID_SIZE)) ) { bucket->entries[ix].inuse = 0; bucket->entries[ix].gptr = 0; bucket->entries[ix].flags = 0; return; } } return; } static uint8_t ks_dhtrt_findclosest_bucketnodes(ks_dhtrt_nodeid_t id, ks_dhtrt_bucket_header_t* header, ks_dhtrt_sortedxors_t* xors, unsigned char* hixor, /*todo: remove */ unsigned int max) { uint8_t count = 0; /* count of nodes added this time */ xors->startix = KS_DHT_BUCKETSIZE; xors->count = 0; unsigned char xorvalue[KS_DHT_NODEID_SIZE]; /* just ugh! - there must be a better way to do this */ /* walk the entire bucket calculating the xor value on the way */ /* add valid & relevant entries to the xor values */ ks_dhtrt_bucket_t* bucket = header->bucket; if (bucket == 0) { /* sanity */ #ifdef KS_DHT_DEBUGPRINTF_ char buf[100]; printf("closestbucketnodes: intermediate tree node found %s\n", ks_dhtrt_printableid(header->mask, buf)); #endif } for(uint8_t ix=0; ixentries[ix].inuse == 1 && ks_dhtrt_isactive( &(bucket->entries[ix])) ) { /* calculate xor value */ ks_dhtrt_xor(bucket->entries[ix].id, id, xorvalue ); /* do we need to hold this one */ if ( count < max || /* yes: we have not filled the quota yet */ (memcmp(xorvalue, hixor, KS_DHT_NODEID_SIZE) < 0)) { /* or is closer node than one already selected */ /* now sort the new xorvalue into the results structure */ /* this now becomes worst case O(n*2) logic - is there a better way */ /* in practice the bucket size is fixed so actual behavior is proably 0(logn) */ unsigned int xorix = xors->startix; /* start of ordered list */ unsigned int prev_xorix = KS_DHT_BUCKETSIZE; for(int ix2=0; ix2xort[xorix].xor, KS_DHT_NODEID_SIZE) > 0) { break; /* insert before xorix, after prev_xoris */ } prev_xorix = xorix; xorix = xors->xort[xorix].nextix; } /* insert point found count -> array slot to added newly identified node insert_point -> the array slot before which we need to insert the newly identified node */ memcpy(xors->xort[count].xor, xorvalue, KS_DHT_NODEID_SIZE); xors->xort[count].ix = ix; xors->xort[count].nextix = xorix; /* correct forward chain */ if (prev_xorix < KS_DHT_BUCKETSIZE) { /* correct backward chain */ xors->xort[prev_xorix].nextix = count; } else { xors->startix = count; } ++count; } } } xors->count = count; return count; /* return count of added nodes */ } static uint8_t ks_dhtrt_load_query(ks_dhtrt_querynodes_t* query, ks_dhtrt_sortedxors_t* xort) { ks_dhtrt_sortedxors_t* current = xort; uint8_t loaded = 0; while(current) { #ifdef KS_DHT_DEBUGPRINTF_ char buf[100]; printf(" loadquery from bucket %s count %d\n", ks_dhtrt_printableid(current->bheader->mask,buf), current->count); #endif int xorix = current->startix; for (uint8_t ix = 0; ix<= current->count && loaded < query->max; ++ix ) { unsigned int z = current->xort[xorix].ix; query->nodes[ix] = current->bheader->bucket->entries[z].gptr; ++loaded; } if (loaded >= query->max) break; current = current->next; } query->count = loaded; return loaded; } void ks_dhtrt_ping(ks_dhtrt_bucket_entry_t* entry) { ++entry->outstanding_pings; /* @todo */ /* set the appropriate command in the node and queue if for processing */ /*ks_dht_node_t* node = entry->gptr; */ #ifdef KS_DHT_DEBUGPRINTF_ char buf[100]; printf(" ping queued for nodeid %s count %d\n", ks_dhtrt_printableid(entry->id,buf), entry->outstanding_pings); #endif return; } /* strictly for shifting the bucketheader mask so format must be a right filled mask (hex: ..ffffffff) */ static void ks_dhtrt_shiftright(uint8_t* id) { unsigned char b0 = 0; unsigned char b1 = 0; for(int i = KS_DHT_NODEID_SIZE-1; i >= 0; --i) { if (id[i] == 0) break; /* beyond mask- we are done */ b1 = id[i] & 0x01; id[i] >>= 1; if (i != (KS_DHT_NODEID_SIZE-1)) { id[i+1] |= (b0 << 7); } b0 = b1; } return; } static void ks_dhtrt_shiftleft(uint8_t* id) { for(int i = KS_DHT_NODEID_SIZE-1; i >= 0; --i) { if (id[i] == 0xff) continue; id[i] <<= 1; id[i] |= 0x01; break; } return; } /* Determine whether id1 or id2 is closer to ref */ /* @todo: remove ? simple memcpy seems to do the job ? static int ks_dhtrt_xorcmp(const uint8_t* id1, const uint8_t* id2, const uint8_t* ref); static int ks_dhtrt_xorcmp(const uint8_t* id1, const uint8_t* id2, const uint8_t* ref) { int i; for (i = 0; i < KS_DHT_NODEID_SIZE; i++) { uint8_t xor1, xor2; if (id1[i] == id2[i]) { continue; } xor1 = id1[i] ^ ref[i]; xor2 = id2[i] ^ ref[i]; if (xor1 < xor2) { return -1; / * id1 is closer * / } return 1; / * id2 is closer * / } return 0; / * id2 and id2 are identical ! * / } */ /* create an xor value from two ids */ static void ks_dhtrt_xor(const uint8_t* id1, const uint8_t* id2, uint8_t* xor) { for (int i = 0; i < KS_DHT_NODEID_SIZE; ++i) { if (id1[i] == id2[i]) { xor[i] = 0; } xor[i] = id1[i] ^ id2[i]; } return; } /* is id masked by mask 1 => yes, 0=> no */ static int ks_dhtrt_ismasked(const uint8_t* id, const unsigned char *mask) { for (int i = 0; i < KS_DHT_NODEID_SIZE; ++i) { if (mask[i] == 0 && id[i] != 0) return 0; else if (mask[i] == 0xff) return 1; else if (id[i] > mask[i]) return 0; } return 1; } static char* ks_dhtrt_printableid(uint8_t* id, char* buffer) { char* t = buffer; memset(buffer, 0, KS_DHT_NODEID_SIZE*2); for (int i = 0; i < KS_DHT_NODEID_SIZE; ++i, buffer+=2) { sprintf(buffer, "%02x", id[i]); } return t; } unsigned char ks_dhtrt_isactive(ks_dhtrt_bucket_entry_t* entry) { /* todo */ return 1; }