/* find an assignable address, if check_expired is true, we check all the expired leases as well. * Maybe this should try expired leases by age... */ uint32_t find_address(int check_expired) { uint32_t addr, ret; struct dhcpOfferedAddr *lease = NULL; addr = server_config.start_ip; /* addr is in host order here */ for (; addr <= server_config.end_ip; addr++) { /* ie, 192.168.55.0 */ if (!(addr & 0xFF)) continue; /* ie, 192.168.55.255 */ if ((addr & 0xFF) == 0xFF) continue; /* Only do if it isn't assigned as a static lease */ ret = htonl(addr); if (!reservedIp(server_config.static_leases, ret)) { /* lease is not taken */ lease = find_lease_by_yiaddr(ret); /* no lease or it expired and we are checking for expired leases */ if ((!lease || (check_expired && lease_expired(lease))) && nobody_responds_to_arp(ret) /* it isn't used on the network */ ) { return ret; } } } return 0; }
/* Find a new usable (we think) address */ uint32_t FAST_FUNC find_free_or_expired_nip(const uint8_t *safe_mac) { uint32_t addr; struct dyn_lease *oldest_lease = NULL; addr = server_config.start_ip; /* addr is in host order here */ for (; addr <= server_config.end_ip; addr++) { uint32_t nip; struct dyn_lease *lease; /* ie, 192.168.55.0 */ if ((addr & 0xff) == 0) continue; /* ie, 192.168.55.255 */ if ((addr & 0xff) == 0xff) continue; nip = htonl(addr); /* is this a static lease addr? */ if (is_nip_reserved(server_config.static_leases, nip)) continue; lease = find_lease_by_nip(nip); if (!lease) { //TODO: DHCP servers do not always sit on the same subnet as clients: should *ping*, not arp-ping! if (nobody_responds_to_arp(nip, safe_mac)) return nip; } else { if (!oldest_lease || lease->expires < oldest_lease->expires) oldest_lease = lease; } } if (oldest_lease && is_expired_lease(oldest_lease) && nobody_responds_to_arp(oldest_lease->lease_nip, safe_mac) ) { return oldest_lease->lease_nip; } return 0; }
/* Find a new usable (we think) address */ uint32_t FAST_FUNC find_free_or_expired_nip(const uint8_t *safe_mac) { uint32_t addr; struct dyn_lease *oldest_lease = NULL; #if ENABLE_FEATURE_UDHCPD_BASE_IP_ON_MAC uint32_t stop; unsigned i, hash; /* hash hwaddr: use the SDBM hashing algorithm. Seems to give good * dispersal even with similarly-valued "strings". */ hash = 0; for (i = 0; i < 6; i++) hash += safe_mac[i] + (hash << 6) + (hash << 16) - hash; /* pick a seed based on hwaddr then iterate until we find a free address. */ addr = server_config.start_ip + (hash % (1 + server_config.end_ip - server_config.start_ip)); stop = addr; #else addr = server_config.start_ip; #define stop (server_config.end_ip + 1) #endif do { uint32_t nip; struct dyn_lease *lease; /* ie, 192.168.55.0 */ if ((addr & 0xff) == 0) goto next_addr; /* ie, 192.168.55.255 */ if ((addr & 0xff) == 0xff) goto next_addr; nip = htonl(addr); /* skip our own address */ if (nip == server_config.server_nip) goto next_addr; /* is this a static lease addr? */ if (is_nip_reserved(server_config.static_leases, nip)) goto next_addr; lease = find_lease_by_nip(nip); if (!lease) { //TODO: DHCP servers do not always sit on the same subnet as clients: should *ping*, not arp-ping! if (nobody_responds_to_arp(nip, safe_mac)) return nip; } else { if (!oldest_lease || lease->expires < oldest_lease->expires) oldest_lease = lease; } next_addr: addr++; #if ENABLE_FEATURE_UDHCPD_BASE_IP_ON_MAC if (addr > server_config.end_ip) addr = server_config.start_ip; #endif } while (addr != stop); if (oldest_lease && is_expired_lease(oldest_lease) && nobody_responds_to_arp(oldest_lease->lease_nip, safe_mac) ) { return oldest_lease->lease_nip; } return 0; }