mirror of
https://github.com/zerotier/ZeroTierOne.git
synced 2024-12-18 20:47:53 +00:00
260 lines
7.5 KiB
C++
260 lines
7.5 KiB
C++
/*
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* Copyright (c)2019 ZeroTier, Inc.
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*
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* Use of this software is governed by the Business Source License included
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* in the LICENSE.TXT file in the project's root directory.
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*
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* Change Date: 2023-01-01
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*
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* On the date above, in accordance with the Business Source License, use
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* of this software will be governed by version 2.0 of the Apache License.
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*/
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/****/
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#include "NeighborDiscovery.hpp"
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#include "OSUtils.hpp"
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#include "../include/ZeroTierOne.h"
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#include <assert.h>
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namespace ZeroTier {
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uint16_t calc_checksum (uint16_t *addr, int len)
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{
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int count = len;
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uint32_t sum = 0;
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uint16_t answer = 0;
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// Sum up 2-byte values until none or only one byte left.
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while (count > 1) {
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sum += *(addr++);
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count -= 2;
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}
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// Add left-over byte, if any.
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if (count > 0) {
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sum += *(uint8_t *) addr;
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}
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// Fold 32-bit sum into 16 bits; we lose information by doing this,
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// increasing the chances of a collision.
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// sum = (lower 16 bits) + (upper 16 bits shifted right 16 bits)
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while (sum >> 16) {
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sum = (sum & 0xffff) + (sum >> 16);
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}
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// Checksum is one's compliment of sum.
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answer = ~sum;
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return (answer);
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}
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struct _pseudo_header {
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uint8_t sourceAddr[16];
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uint8_t targetAddr[16];
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uint32_t length;
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uint8_t zeros[3];
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uint8_t next; // 58
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};
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struct _option {
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_option(int optionType)
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: type(optionType)
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, length(8)
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{
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memset(mac, 0, sizeof(mac));
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}
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uint8_t type;
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uint8_t length;
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uint8_t mac[6];
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};
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struct _neighbor_solicitation {
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_neighbor_solicitation()
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: type(135)
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, code(0)
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, checksum(0)
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, option(1)
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{
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memset(&reserved, 0, sizeof(reserved));
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memset(target, 0, sizeof(target));
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}
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void calculateChecksum(const sockaddr_storage &sourceIp, const sockaddr_storage &destIp) {
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_pseudo_header ph;
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memset(&ph, 0, sizeof(_pseudo_header));
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const sockaddr_in6 *src = (const sockaddr_in6*)&sourceIp;
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const sockaddr_in6 *dest = (const sockaddr_in6*)&destIp;
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memcpy(ph.sourceAddr, &src->sin6_addr, sizeof(struct in6_addr));
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memcpy(ph.targetAddr, &dest->sin6_addr, sizeof(struct in6_addr));
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ph.next = 58;
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ph.length = htonl(sizeof(_neighbor_solicitation));
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size_t len = sizeof(_pseudo_header) + sizeof(_neighbor_solicitation);
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uint8_t *tmp = (uint8_t*)malloc(len);
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memcpy(tmp, &ph, sizeof(_pseudo_header));
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memcpy(tmp+sizeof(_pseudo_header), this, sizeof(_neighbor_solicitation));
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checksum = calc_checksum((uint16_t*)tmp, (int)len);
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free(tmp);
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tmp = NULL;
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}
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uint8_t type; // 135
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uint8_t code; // 0
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uint16_t checksum;
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uint32_t reserved;
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uint8_t target[16];
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_option option;
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};
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struct _neighbor_advertisement {
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_neighbor_advertisement()
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: type(136)
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, code(0)
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, checksum(0)
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, rso(0x40)
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, option(2)
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{
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memset(padding, 0, sizeof(padding));
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memset(target, 0, sizeof(target));
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}
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void calculateChecksum(const sockaddr_storage &sourceIp, const sockaddr_storage &destIp) {
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_pseudo_header ph;
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memset(&ph, 0, sizeof(_pseudo_header));
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const sockaddr_in6 *src = (const sockaddr_in6*)&sourceIp;
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const sockaddr_in6 *dest = (const sockaddr_in6*)&destIp;
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memcpy(ph.sourceAddr, &src->sin6_addr, sizeof(struct in6_addr));
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memcpy(ph.targetAddr, &dest->sin6_addr, sizeof(struct in6_addr));
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ph.next = 58;
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ph.length = htonl(sizeof(_neighbor_advertisement));
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size_t len = sizeof(_pseudo_header) + sizeof(_neighbor_advertisement);
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uint8_t *tmp = (uint8_t*)malloc(len);
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memcpy(tmp, &ph, sizeof(_pseudo_header));
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memcpy(tmp+sizeof(_pseudo_header), this, sizeof(_neighbor_advertisement));
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checksum = calc_checksum((uint16_t*)tmp, (int)len);
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free(tmp);
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tmp = NULL;
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}
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uint8_t type; // 136
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uint8_t code; // 0
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uint16_t checksum;
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uint8_t rso;
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uint8_t padding[3];
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uint8_t target[16];
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_option option;
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};
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NeighborDiscovery::NeighborDiscovery()
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: _cache(256)
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, _lastCleaned(OSUtils::now())
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{}
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void NeighborDiscovery::addLocal(const sockaddr_storage &address, const MAC &mac)
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{
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_NDEntry &e = _cache[InetAddress(address)];
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e.lastQuerySent = 0;
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e.lastResponseReceived = 0;
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e.mac = mac;
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e.local = true;
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}
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void NeighborDiscovery::remove(const sockaddr_storage &address)
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{
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_cache.erase(InetAddress(address));
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}
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sockaddr_storage NeighborDiscovery::processIncomingND(const uint8_t *nd, unsigned int len, const sockaddr_storage &localIp, uint8_t *response, unsigned int &responseLen, MAC &responseDest)
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{
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assert(sizeof(_neighbor_solicitation) == 28);
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assert(sizeof(_neighbor_advertisement) == 32);
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const uint64_t now = OSUtils::now();
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sockaddr_storage ip = {0};
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if (len >= sizeof(_neighbor_solicitation) && nd[0] == 0x87) {
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// respond to Neighbor Solicitation request for local address
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_neighbor_solicitation solicitation;
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memcpy(&solicitation, nd, len);
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InetAddress targetAddress(solicitation.target, 16, 0);
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_NDEntry *targetEntry = _cache.get(targetAddress);
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if (targetEntry && targetEntry->local) {
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_neighbor_advertisement adv;
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targetEntry->mac.copyTo(adv.option.mac, 6);
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memcpy(adv.target, solicitation.target, 16);
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adv.calculateChecksum(localIp, targetAddress);
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memcpy(response, &adv, sizeof(_neighbor_advertisement));
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responseLen = sizeof(_neighbor_advertisement);
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responseDest.setTo(solicitation.option.mac, 6);
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}
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} else if (len >= sizeof(_neighbor_advertisement) && nd[0] == 0x88) {
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_neighbor_advertisement adv;
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memcpy(&adv, nd, len);
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InetAddress responseAddress(adv.target, 16, 0);
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_NDEntry *queryEntry = _cache.get(responseAddress);
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if(queryEntry && !queryEntry->local && (now - queryEntry->lastQuerySent <= ZT_ND_QUERY_MAX_TTL)) {
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queryEntry->lastResponseReceived = now;
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queryEntry->mac.setTo(adv.option.mac, 6);
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ip = responseAddress;
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}
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}
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if ((now - _lastCleaned) >= ZT_ND_EXPIRE) {
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_lastCleaned = now;
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Hashtable<InetAddress, _NDEntry>::Iterator i(_cache);
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InetAddress *k = NULL;
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_NDEntry *v = NULL;
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while (i.next(k, v)) {
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if(!v->local && (now - v->lastResponseReceived) >= ZT_ND_EXPIRE) {
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_cache.erase(*k);
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}
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}
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}
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return ip;
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}
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MAC NeighborDiscovery::query(const MAC &localMac, const sockaddr_storage &localIp, const sockaddr_storage &targetIp, uint8_t *query, unsigned int &queryLen, MAC &queryDest)
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{
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const uint64_t now = OSUtils::now();
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InetAddress localAddress(localIp);
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localAddress.setPort(0);
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InetAddress targetAddress(targetIp);
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targetAddress.setPort(0);
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_NDEntry &e = _cache[targetAddress];
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if ( (e.mac && ((now - e.lastResponseReceived) >= (ZT_ND_EXPIRE / 3))) ||
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(!e.mac && ((now - e.lastQuerySent) >= ZT_ND_QUERY_INTERVAL))) {
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e.lastQuerySent = now;
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_neighbor_solicitation ns;
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memcpy(ns.target, targetAddress.rawIpData(), 16);
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localMac.copyTo(ns.option.mac, 6);
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ns.calculateChecksum(localIp, targetIp);
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if (e.mac) {
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queryDest = e.mac;
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} else {
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queryDest = (uint64_t)0xffffffffffffULL;
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}
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} else {
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queryLen = 0;
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queryDest.zero();
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}
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return e.mac;
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}
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}
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