Added DHCP-Relay-IP-Address

only in the reply, which is copied from the original giaddr

diff --git a/share/dictionary.dhcp b/share/dictionary.dhcp
index 3c61087..d2cd8f4 100644 (file)
--- a/share/dictionary.dhcp
+++ b/share/dictionary.dhcp
@@ -50,6 +50,10 @@ ATTRIBUTE    DHCP-Boot-Filename                      269     string    # 128 octets
 ATTRIBUTE      DHCP-Relay-To-IP-Address                270     ipaddr
 ATTRIBUTE      DHCP-Relay-Max-Hop-Count                271     integer
 
+# This is copied from the request packet, giaddr, and
+# added to the reply packet by the server core.
+ATTRIBUTE      DHCP-Relay-IP-Address                   272     ipaddr
+
 VALUE  DHCP-Flags                      Broadcast               0x8000
 
 

diff --git a/src/main/dhcpd.c b/src/main/dhcpd.c
index 1c6d5db..d12e42c 100644 (file)
--- a/src/main/dhcpd.c
+++ b/src/main/dhcpd.c
@@ -271,6 +271,21 @@ static int dhcp_process(REQUEST *request)
        VALUE_PAIR *vp;
        dhcp_socket_t *sock;
 
+       /*
+        *      If there's a giaddr, save it as the Relay-IP-Address
+        *      in the response.  That way the later code knows where
+        *      to send the reply.
+        */
+       vp = pairfind(request->packet->vps, DHCP2ATTR(266)); /* DHCP-Gateway-IP-Address */
+       if (vp && (vp->vp_ipaddr != htonl(INADDR_ANY))) {
+               VALUE_PAIR *relay;
+
+               /* DHCP-Relay-IP-Address */
+               relay = radius_paircreate(request, &request->reply->vps,
+                                         DHCP2ATTR(272), PW_TYPE_IPADDR);
+               if (relay) relay->vp_ipaddr = vp->vp_ipaddr;
+       }
+
        vp = pairfind(request->packet->vps, DHCP2ATTR(53)); /* DHCP-Message-Type */
        if (vp) {
                DICT_VALUE *dv = dict_valbyattr(DHCP2ATTR(53), vp->vp_integer);
@@ -396,17 +411,41 @@ static int dhcp_process(REQUEST *request)
        request->reply->dst_port = request->packet->src_port;
        request->reply->src_port = request->packet->dst_port;
 
+       /*
+        *      Answer to client's nearest DHCP relay.
+        *
+        *      Which may be different than the giaddr given in the
+        *      packet to the client.  i.e. the relay may have a
+        *      public IP, but the gateway a private one.
+        */
+       vp = pairfind(request->reply->vps, DHCP2ATTR(272)); /* DHCP-Relay-IP-Address */
+       if (vp) {
+               RDEBUG("DHCP: Reply will be unicast to giaddr from original packet");
+               request->reply->dst_ipaddr.ipaddr.ip4addr.s_addr = vp->vp_ipaddr;
+               return 1;
+       }
+
+       /*
+        *      Answer to client's nearest DHCP gateway.  In this
+        *      case, the client can reach the gateway, as can the
+        *      server.
+        */
        vp = pairfind(request->reply->vps, DHCP2ATTR(266)); /* DHCP-Gateway-IP-Address */
        if (vp && (vp->vp_ipaddr != htonl(INADDR_ANY))) {
-               /* Answer to client's nearest DHCP relay */
                RDEBUG("DHCP: Reply will be unicast to giaddr");
                request->reply->dst_ipaddr.ipaddr.ip4addr.s_addr = vp->vp_ipaddr;
+               return 1;
+       }
 
-       } else if ((request->reply->code == PW_DHCP_NAK) ||
-           ((vp = pairfind(request->reply->vps, DHCP2ATTR(262))) /* DHCP-Flags */ &&
-               (vp->vp_integer & 0x8000) &&
-               ((vp = pairfind(request->reply->vps, DHCP2ATTR(263))) /* DHCP-Client-IP-Address */ &&
-                   (vp->vp_ipaddr == htonl(INADDR_ANY))))) {
+       /*
+        *      If it's a NAK, or the broadcast flag was set, ond
+        *      there's no client-ip-address, send a broadcast.
+        */
+       if ((request->reply->code == PW_DHCP_NAK) ||
+           ((vp = pairfind(request->reply->vps, DHCP2ATTR(262))) && /* DHCP-Flags */
+                   (vp->vp_integer & 0x8000) &&
+            ((vp = pairfind(request->reply->vps, DHCP2ATTR(263))) && /* DHCP-Client-IP-Address */
+             (vp->vp_ipaddr == htonl(INADDR_ANY))))) {
                /*
                 * RFC 2131, page 23
                 *
@@ -417,43 +456,46 @@ static int dhcp_process(REQUEST *request)
                 */
                RDEBUG("DHCP: Reply will be broadcast");
                request->reply->dst_ipaddr.ipaddr.ip4addr.s_addr = htonl(INADDR_BROADCAST);
-       } else {
-               /*
-                * RFC 2131, page 23
-                *
-                * Unicast to
-                * - ciaddr if present
-                * otherwise to yiaddr
-                */
-               if ((vp = pairfind(request->reply->vps, DHCP2ATTR(263))) /* DHCP-Client-IP-Address */ &&
-                   (vp->vp_ipaddr != htonl(INADDR_ANY))) {
-                       RDEBUG("DHCP: Reply will be sent unicast to client-ip-address");
-                       request->reply->dst_ipaddr.ipaddr.ip4addr.s_addr = vp->vp_ipaddr;
-               } else {
-                       vp = pairfind(request->reply->vps, DHCP2ATTR(264)); /* DHCP-Your-IP-Address */
-                       if (!vp) {
-                               DEBUG("DHCP: Failed to find IP Address for request.");
-                               return -1;
-                       }
-                       
-                       RDEBUG("DHCP: Reply will be sent unicast to your-ip-address");
-                       request->reply->dst_ipaddr.ipaddr.ip4addr.s_addr = vp->vp_ipaddr;
-
-                       /*
-                        * 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->reply->code == PW_DHCP_OFFER) {
-                               VALUE_PAIR *hwvp = pairfind(request->reply->vps, DHCP2ATTR(267)); /* DHCP-Client-Hardware-Address */
+               return 1;
+       }
 
-                               if (!hwvp) return -1;
+       /*
+        *      RFC 2131, page 23
+        *
+        *      Unicast to ciaddr if present, otherwise to yiaddr.
+        */
+       if ((vp = pairfind(request->reply->vps, DHCP2ATTR(263))) && /* DHCP-Client-IP-Address */
+           (vp->vp_ipaddr != htonl(INADDR_ANY))) {
+               RDEBUG("DHCP: Reply will be sent unicast to client-ip-address");
+               request->reply->dst_ipaddr.ipaddr.ip4addr.s_addr = vp->vp_ipaddr;
+               return 1;
+       }
 
-                               if (fr_dhcp_add_arp_entry(request->reply->sockfd, sock->src_interface, hwvp, vp) < 0) {
-                                       return -1;
-                               }
-                       }
+       vp = pairfind(request->reply->vps, DHCP2ATTR(264)); /* DHCP-Your-IP-Address */
+       if (!vp) {
+               DEBUG("DHCP: Failed to find DHCP-Your-IP-Address for request.");
+               return -1;
+       }
+       
+       RDEBUG("DHCP: Reply will be sent unicast to your-ip-address");
+       request->reply->dst_ipaddr.ipaddr.ip4addr.s_addr = vp->vp_ipaddr;
+       
+       /*
+        *      When sending a DHCP_OFFER, make sure our ARP table
+        *      contains an entry for the client IP address.
+        *      Otherwise the packet may not be sent to the client, as
+        *      the OS has no ARP entry for it.
+        *
+        *      This is a cute hack to avoid us having to create a raw
+        *      socket to send DHCP packets.
+        */
+       if (request->reply->code == PW_DHCP_OFFER) {
+               VALUE_PAIR *hwvp = pairfind(request->reply->vps, DHCP2ATTR(267)); /* DHCP-Client-Hardware-Address */
+               
+               if (!hwvp) return -1;
+               
+               if (fr_dhcp_add_arp_entry(request->reply->sockfd, sock->src_interface, hwvp, vp) < 0) {
+                       return -1;
                }
        }
 
@@ -511,8 +553,6 @@ static int dhcp_socket_parse(CONF_SECTION *cs, rad_listen_t *this)
        sock->suppress_responses = FALSE;
        cp = cf_pair_find(cs, "suppress_responses");
        if (cp) {
-               const char *value;
-
                cf_item_parse(cs, "suppress_responses", PW_TYPE_BOOLEAN,
                              &sock->suppress_responses, NULL);
        }