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sd-dhcp-server: Send replies to BOOTP relay server port

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RFC 2131 Section 4.1 says that

 "If the ’giaddr’ field in a DHCP message from a client is non-zero,
  the server sends any return messages to the ’DHCP server’ port on the
  BOOTP relay agent whose address appears in ’giaddr’."

Fix this by adding a destination port when sending unicast UDP packets
and provide the server port when a BOOTP relay agent is being used.
This commit is contained in:
Patrik Flykt 2016-02-25 15:36:40 +02:00
parent 96b08d65a1
commit 8eb7b6a595
1 changed files with 9 additions and 4 deletions
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13
src/libsystemd-network/sd-dhcp-server.c
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@ -280,10 +280,11 @@ static int dhcp_server_send_unicast_raw(sd_dhcp_server *server,
}
static int dhcp_server_send_udp(sd_dhcp_server *server, be32_t destination,
uint16_t destination_port,
DHCPMessage *message, size_t len) {
union sockaddr_union dest = {
.in.sin_family = AF_INET,
.in.sin_port = htobe16(DHCP_PORT_CLIENT),
.in.sin_port = htobe16(destination_port),
.in.sin_addr.s_addr = destination,
};
struct iovec iov = {
@ -342,6 +343,7 @@ int dhcp_server_send_packet(sd_dhcp_server *server,
DHCPRequest *req, DHCPPacket *packet,
int type, size_t optoffset) {
be32_t destination = INADDR_ANY;
uint16_t destination_port = DHCP_PORT_CLIENT;
int r;
assert(server);
@ -386,17 +388,19 @@ int dhcp_server_send_packet(sd_dhcp_server *server,
*/
if (req->message->giaddr) {
destination = req->message->giaddr;
destination_port = DHCP_PORT_SERVER;
if (type == DHCP_NAK)
packet->dhcp.flags = htobe16(0x8000);
} else if (req->message->ciaddr && type != DHCP_NAK)
destination = req->message->ciaddr;
if (destination != INADDR_ANY)
return dhcp_server_send_udp(server, destination, &packet->dhcp,
return dhcp_server_send_udp(server, destination,
destination_port, &packet->dhcp,
sizeof(DHCPMessage) + optoffset);
else if (requested_broadcast(req) || type == DHCP_NAK)
return dhcp_server_send_udp(server, INADDR_BROADCAST,
&packet->dhcp,
destination_port, &packet->dhcp,
sizeof(DHCPMessage) + optoffset);
else
/* we cannot send UDP packet to specific MAC address when the
@ -579,7 +583,8 @@ static int server_send_forcerenew(sd_dhcp_server *server, be32_t address,
memcpy(&packet->dhcp.chaddr, chaddr, ETH_ALEN);
r = dhcp_server_send_udp(server, address, &packet->dhcp,
r = dhcp_server_send_udp(server, address, DHCP_PORT_CLIENT,
&packet->dhcp,
sizeof(DHCPMessage) + optoffset);
if (r < 0)
return r;