chiark / gitweb /
dhcp: Support seconds elapsed since start of DHCP negotiation
authorPatrik Flykt <patrik.flykt@linux.intel.com>
Mon, 9 Dec 2013 21:43:22 +0000 (23:43 +0200)
committerZbigniew Jędrzejewski-Szmek <zbyszek@in.waw.pl>
Thu, 12 Dec 2013 16:43:34 +0000 (11:43 -0500)
It was noticed by Grant Erickson in ConnMan commit
95e15c09350acf58d4707056ae2614570883ef66 that:

   "Certain DHCP servers, such as that implemented in Mac OS X
    (< 10.7) for its "Internet Sharing" feature, refuse to issue
    a DHCP lease to clients that have not set a non-zero value
    in their DISCOVER or REQUEST packets."

src/libsystemd-dhcp/dhcp-client.c

index 4d1722f..181c6f8 100644 (file)
@@ -120,8 +120,8 @@ int sd_dhcp_client_set_mac(sd_dhcp_client *client,
 }
 
 static int client_packet_init(sd_dhcp_client *client, uint8_t type,
-                              DHCPMessage *message, uint8_t **opt,
-                              size_t *optlen)
+                              DHCPMessage *message, uint16_t secs,
+                              uint8_t **opt, size_t *optlen)
 {
         int err;
 
@@ -136,6 +136,10 @@ static int client_packet_init(sd_dhcp_client *client, uint8_t type,
         message->hlen = ETHER_ADDR_LEN;
         message->xid = htobe32(client->xid);
 
+        /* Although 'secs' field is a SHOULD in RFC 2131, certain DHCP servers
+           refuse to issue an DHCP lease if 'secs' is set to zero */
+        message->secs = htobe16(secs);
+
         memcpy(&message->chaddr, &client->mac_addr, ETH_ALEN);
         (*opt)[0] = 0x63;
         (*opt)[1] = 0x82;
@@ -189,7 +193,7 @@ static uint16_t client_checksum(void *buf, int len)
         return ~((sum & 0xffff) + (sum >> 16));
 }
 
-static int client_send_discover(sd_dhcp_client *client)
+static int client_send_discover(sd_dhcp_client *client, uint16_t secs)
 {
         int err = 0;
         _cleanup_free_ DHCPPacket *discover;
@@ -205,7 +209,7 @@ static int client_send_discover(sd_dhcp_client *client)
                 return -ENOMEM;
 
         err = client_packet_init(client, DHCP_DISCOVER, &discover->dhcp,
-                                 &opt, &optlen);
+                                 secs, &opt, &optlen);
         if (err < 0)
                 return err;
 
@@ -256,7 +260,7 @@ int sd_dhcp_client_start(sd_dhcp_client *client)
 
         client->xid = random_u();
 
-        return client_send_discover(client);
+        return client_send_discover(client, 0);
 }
 
 sd_dhcp_client *sd_dhcp_client_new(void)