static int dhcprelay_process_client_request(REQUEST *request)
{
int rcode;
uint8_t maxhops = 16;
VALUE_PAIR *vp, *giaddr;
dhcp_socket_t *sock;
RADIUS_PACKET *packet;
rad_assert(request->packet->data[0] == 1);
/*
* Do the forward by ourselves, do not rely on dhcp_socket_send()
*/
request->reply->code = 0;
/*
* It's invalid to have giaddr=0 AND a relay option
*/
giaddr = fr_pair_find_by_num(request->packet->vps, DHCP_MAGIC_VENDOR, 266, TAG_ANY); /* DHCP-Gateway-IP-Address */
if (giaddr && (giaddr->vp_ipv4addr == htonl(INADDR_ANY)) &&
fr_pair_find_by_num(request->packet->vps, DHCP_MAGIC_VENDOR, 82, TAG_ANY)) { /* DHCP-Relay-Agent-Information */
RDEBUG2("Received packet with giaddr = 0 and containing relay option: Discarding packet");
return 1;
}
/*
* RFC 1542 (BOOTP), page 15
*
* Drop requests if hop-count > 16 or admin specified another value
*/
if ((vp = fr_pair_find_by_num(request->control, DHCP_MAGIC_VENDOR, 271, TAG_ANY))) { /* DHCP-Relay-Max-Hop-Count */
maxhops = vp->vp_uint32;
}
vp = fr_pair_find_by_num(request->packet->vps, DHCP_MAGIC_VENDOR, 259, TAG_ANY); /* DHCP-Hop-Count */
rad_assert(vp != NULL);
if (vp->vp_uint8 > maxhops) {
RDEBUG2("Number of hops is greater than %d: not relaying", maxhops);
return 1;
} else {
/* Increment hop count */
vp->vp_uint8++;
}
sock = request->listener->data;
/*
* Don't muck with the original request packet. That's
* bad form. Plus, dhcp_encode() does nothing if
* packet->data is already set.
*/
packet = fr_radius_alloc(request, false);
rcode = -1;
/*
* Forward the request to the next server using the
* incoming request as a template.
*/
packet->code = request->packet->code;
packet->sockfd = request->packet->sockfd;
/*
* Forward the request to the next server using the
* incoming request as a template.
*/
/* set SRC ipaddr/port to the listener ipaddr/port */
packet->src_ipaddr.af = AF_INET;
packet->src_ipaddr.addr.v4.s_addr = sock->lsock.my_ipaddr.addr.v4.s_addr;
packet->src_port = sock->lsock.my_port;
vp = fr_pair_find_by_num(request->control, DHCP_MAGIC_VENDOR, 270, TAG_ANY); /* DHCP-Relay-To-IP-Address */
rad_assert(vp != NULL);
/* set DEST ipaddr/port to the next server ipaddr/port */
packet->dst_ipaddr.af = AF_INET;
packet->dst_ipaddr.addr.v4.s_addr = vp->vp_ipv4addr;
packet->dst_port = sock->lsock.my_port;
packet->vps = request->packet->vps; /* hackity hack */
/*
* Relaying is not proxying, we just forward it on and forget
* about it, not sending a response to the DHCP client.
*/
dhcp_packet_debug(request, packet, false);
if (fr_dhcpv4_packet_encode(packet) < 0) {
RPERROR("Failed encoding DHCP packet");
goto error;
}
rcode = fr_dhcpv4_udp_packet_send(packet);
error:
packet->vps = NULL;
talloc_free(packet);
return rcode;
}
static int send_with_socket(RADIUS_PACKET **reply, RADIUS_PACKET *request)
{
int on = 1;
#ifdef HAVE_LINUX_IF_PACKET_H
if (raw_mode) {
sockfd = fr_dhcpv4_raw_socket_open(&ll, iface_ind);
if (sockfd < 0) {
ERROR("Error opening socket");
return -1;
}
} else
#endif
{
sockfd = fr_socket_server_udp(&request->src_ipaddr, &request->src_port, NULL, false);
if (sockfd < 0) {
ERROR("Error opening socket: %s", fr_strerror());
return -1;
}
if (fr_socket_bind(sockfd, &request->src_ipaddr, &request->src_port, NULL) < 0) {
ERROR("Error binding socket: %s", fr_strerror());
return -1;
}
}
/*
* Set option 'receive timeout' on socket.
* Note: in case of a timeout, the error will be "Resource temporarily unavailable".
*/
if (setsockopt(sockfd, SOL_SOCKET, SO_RCVTIMEO, (char *)&tv_timeout, sizeof(struct timeval)) == -1) {
ERROR("Failed setting socket timeout: %s", fr_syserror(errno));
return -1;
}
if (setsockopt(sockfd, SOL_SOCKET, SO_BROADCAST, &on, sizeof(on)) < 0) {
ERROR("Can't set broadcast option: %s", fr_syserror(errno));
return -1;
}
request->sockfd = sockfd;
#ifdef HAVE_LINUX_IF_PACKET_H
if (raw_mode) {
if (fr_dhcpv4_raw_packet_send(sockfd, &ll, request) < 0) {
ERROR("Failed sending (fr_dhcpv4_raw_packet_send): %s", fr_syserror(errno));
return -1;
}
if (!reply_expected) return 0;
*reply = fr_dhcpv4_recv_raw_loop(sockfd, &ll, request);
if (!*reply) {
ERROR("Error receiving reply (fr_dhcpv4_recv_raw_loop)");
return -1;
}
} else
#endif
{
if (fr_dhcpv4_udp_packet_send(request) < 0) {
ERROR("Failed sending: %s", fr_syserror(errno));
return -1;
}
if (!reply_expected) return 0;
*reply = fr_dhcpv4_udp_packet_recv(sockfd);
if (!*reply) {
if (errno == EAGAIN) {
fr_strerror(); /* clear error */
ERROR("Timed out waiting for reply");
} else {
ERROR("Error receiving reply");
}
return -1;
}
}
return 0;
}
/*
* We've seen a reply from a server.
* i.e. we're a relay.
*/
static int dhcprelay_process_server_reply(REQUEST *request)
{
int rcode;
VALUE_PAIR *vp, *giaddr;
dhcp_socket_t *sock;
RADIUS_PACKET *packet;
rad_assert(request->packet->data[0] == 2);
/*
* Do the forward by ourselves, do not rely on dhcp_socket_send()
*/
request->reply->code = 0;
sock = request->listener->data;
/*
* Check that packet is for us.
*/
giaddr = fr_pair_find_by_num(request->packet->vps, DHCP_MAGIC_VENDOR, 266, TAG_ANY); /* DHCP-Gateway-IP-Address */
/* --with-udpfromto is needed just for the following test */
if (!giaddr || giaddr->vp_ipv4addr != request->packet->dst_ipaddr.addr.v4.s_addr) {
RDEBUG2("Packet received from server was not for us (was for 0x%x). Discarding packet",
ntohl(request->packet->dst_ipaddr.addr.v4.s_addr));
return 1;
}
/*
* Don't muck with the original request packet. That's
* bad form. Plus, dhcp_encode() does nothing if
* packet->data is already set.
*/
packet = fr_radius_alloc(request, false);
rcode = -1;
/*
* Forward the request to the next server using the
* incoming request as a template.
*/
packet->code = request->packet->code;
packet->sockfd = request->packet->sockfd;
/* set SRC ipaddr/port to the listener ipaddr/port */
packet->src_ipaddr.af = AF_INET;
packet->src_port = sock->lsock.my_port;
/* set DEST ipaddr/port to clientip/68 or broadcast in specific cases */
packet->dst_ipaddr.af = AF_INET;
/*
* We're a relay, and send the reply to giaddr.
*/
packet->dst_ipaddr.addr.v4.s_addr = htonl(INADDR_BROADCAST);
packet->dst_port = request->packet->dst_port; /* server port */
vp = fr_pair_find_by_num(request->control, DHCP_MAGIC_VENDOR, 270, TAG_ANY); /* DHCP-Relay-To-IP-Address */
if (vp) {
RDEBUG("DHCP: response will be relayed to previous gateway");
packet->dst_ipaddr.addr.v4.s_addr = vp->vp_ipv4addr;
giaddr->vp_ipv4addr = vp->vp_ipv4addr;
} else if ((packet->code == FR_DHCP_NAK) ||
!sock->src_interface ||
((vp = fr_pair_find_by_num(request->packet->vps, DHCP_MAGIC_VENDOR, 262, TAG_ANY)) /* DHCP-Flags */ &&
(vp->vp_uint32 & 0x8000) &&
((vp = fr_pair_find_by_num(request->packet->vps, DHCP_MAGIC_VENDOR, 263, TAG_ANY)) /* DHCP-Client-IP-Address */ &&
(vp->vp_ipv4addr == htonl(INADDR_ANY))))) {
/*
* RFC 2131, page 23
*
* Broadcast on
* - DHCPNAK
* or
* - Broadcast flag is set up and ciaddr == NULL
*/
RDEBUG2("Response will be broadcast");
packet->dst_ipaddr.addr.v4.s_addr = htonl(INADDR_BROADCAST);
} else if ((vp = fr_pair_find_by_num(request->packet->vps, DHCP_MAGIC_VENDOR, 263, TAG_ANY)) /* DHCP-Client-IP-Address */ &&
(vp->vp_ipv4addr != htonl(INADDR_ANY))) {
/*
* RFC 2131, page 23
*
* Unicast to
* - ciaddr if present
* otherwise to yiaddr
*/
packet->dst_ipaddr.addr.v4.s_addr = vp->vp_ipv4addr;
} else {
vp = fr_pair_find_by_num(request->packet->vps, DHCP_MAGIC_VENDOR, 264, TAG_ANY); /* DHCP-Your-IP-Address */
if (!vp) {
RPEDEBUG("Failed to find IP Address for request");
goto error;
}
RDEBUG2("Response will be unicast to &DHCP-Your-IP-Address");
packet->dst_ipaddr.addr.v4.s_addr = vp->vp_ipv4addr;
/*
* When sending a DHCP_OFFER, make sure our ARP table
* contains an entry for the client IP address, or else
* packet may not be forwarded if it was the first time
* the client was requesting an IP address.
*/
if (request->packet->code == FR_DHCP_OFFER) {
VALUE_PAIR *hwvp = fr_pair_find_by_num(request->packet->vps, DHCP_MAGIC_VENDOR, 267,
TAG_ANY); /* DHCP-Client-Hardware-Address */
if (hwvp == NULL) {
RDEBUG2("DHCP_OFFER packet received with no Client Hardware Address. "
"Discarding packet");
goto error;
}
if (fr_dhcpv4_udp_add_arp_entry(request->packet->sockfd, sock->src_interface,
&vp->vp_ip, hwvp->vp_ether) < 0) {
REDEBUG("Failed adding ARP entry");
goto error;
}
}
}
packet->vps = request->packet->vps; /* hackity hack */
/*
* Our response doesn't go through process.c
*/
dhcp_packet_debug(request, packet, false);
if (fr_dhcpv4_packet_encode(packet) < 0) {
RPERROR("Failed encoding DHCP packet");
goto error;
}
rcode = fr_dhcpv4_udp_packet_send(request->packet);
error:
packet->vps = NULL;
talloc_free(packet);
return rcode;
}
