https://git.reactos.org/?p=reactos.git;a=commitdiff;h=2047cf361327fe1efc46ef58e2ac0e8595d7d468
commit 2047cf361327fe1efc46ef58e2ac0e8595d7d468 Author: Eric Kohl <[email protected]> AuthorDate: Mon May 24 15:18:58 2021 +0200 Commit: Eric Kohl <[email protected]> CommitDate: Mon May 24 15:18:58 2021 +0200 [DHCPCSRV] Send an ARP request to check if an automatic private address is available --- base/services/dhcpcsvc/dhcp/dhclient.c | 48 +++++++++++++++++++++++++--------- 1 file changed, 36 insertions(+), 12 deletions(-) diff --git a/base/services/dhcpcsvc/dhcp/dhclient.c b/base/services/dhcpcsvc/dhcp/dhclient.c index 81fcd9c5000..f97a7ca83df 100644 --- a/base/services/dhcpcsvc/dhcp/dhclient.c +++ b/base/services/dhcpcsvc/dhcp/dhclient.c @@ -1071,26 +1071,50 @@ state_panic(void *ipp) struct interface_info *ip = ipp; uint16_t address_low; int i; - PDHCP_ADAPTER Adapter = AdapterFindInfo(ip); + IPAddr IpAddress; + ULONG Buffer[20]; + ULONG BufferSize; + DWORD ret; + PDHCP_ADAPTER Adapter = AdapterFindInfo(ip); note("No DHCPOFFERS received."); - if (!Adapter->NteContext) - { - /* Generate an automatic private address */ - DbgPrint("DHCPCSVC: Failed to receive a response from a DHCP server. An automatic private address will be assigned.\n"); + if (!Adapter->NteContext) + { + /* Generate an automatic private address */ + DbgPrint("DHCPCSVC: Failed to receive a response from a DHCP server. An automatic private address will be assigned.\n"); + + /* FIXME: The address generation code sucks */ + srand(0); - /* FIXME: The address generation code sucks */ - srand(0); + for (;;) + { address_low = rand(); for (i = 0; i < ip->hw_address.hlen; i++) address_low += ip->hw_address.haddr[i]; - AddIPAddress(htonl(0xA9FE0000 | address_low), //169.254.X.X - htonl(0xFFFF0000), //255.255.0.0 - Adapter->IfMib.dwIndex, - &Adapter->NteContext, - &Adapter->NteInstance); + + IpAddress = htonl(0xA9FE0000 | address_low); // 169.254.X.X + + /* Send an ARP request to check if the IP address is already in use */ + BufferSize = sizeof(Buffer); + ret = SendARP(IpAddress, + IpAddress, + Buffer, + &BufferSize); + DH_DbgPrint(MID_TRACE,("DHCPCSVC: SendARP returned %lu\n", ret)); + if (ret != 0) + { + /* The IP address is not in use */ + DH_DbgPrint(MID_TRACE,("DHCPCSVC: Using automatic private address\n")); + AddIPAddress(IpAddress, + htonl(0xFFFF0000), // 255.255.0.0 + Adapter->IfMib.dwIndex, + &Adapter->NteContext, + &Adapter->NteInstance); + return; + } } + } } void
