1 files changed, 19 insertions, 32 deletions

diff --git a/networking/udhcp/dhcpc.c b/networking/udhcp/dhcpc.c
index b80ea2f40..1c3c478ac 100644
--- a/networking/udhcp/dhcpc.c
+++ b/networking/udhcp/dhcpc.c
@@ -605,7 +605,7 @@ static void init_packet(struct dhcp_packet *packet, char type)
         /* Fill in: op, htype, hlen, cookie fields; message type option: */
         udhcp_init_header(packet, type);
 
-        packet->xid = random_xid();
+        packet->xid = client_data.xid;
 
         client_data.last_secs = monotonic_sec();
         if (client_data.first_secs == 0)
@@ -719,17 +719,15 @@ static int bcast_or_ucast(struct dhcp_packet *packet, uint32_t ciaddr, uint32_t
 
 /* Broadcast a DHCP discover packet to the network, with an optionally requested IP */
 /* NOINLINE: limit stack usage in caller */
-static NOINLINE int send_discover(uint32_t xid, uint32_t requested)
+static NOINLINE int send_discover(uint32_t requested)
 {
         struct dhcp_packet packet;
 
         /* Fill in: op, htype, hlen, cookie, chaddr fields,
-         * random xid field (we override it below),
-         * message type option:
+         * xid field, message type option:
          */
         init_packet(&packet, DHCPDISCOVER);
 
-        packet.xid = xid;
         if (requested)
                 udhcp_add_simple_option(&packet, DHCP_REQUESTED_IP, requested);
 
@@ -747,7 +745,7 @@ static NOINLINE int send_discover(uint32_t xid, uint32_t requested)
  * "The client _broadcasts_ a DHCPREQUEST message..."
  */
 /* NOINLINE: limit stack usage in caller */
-static NOINLINE int send_select(uint32_t xid, uint32_t server, uint32_t requested)
+static NOINLINE int send_select(uint32_t server, uint32_t requested)
 {
         struct dhcp_packet packet;
         struct in_addr temp_addr;
@@ -766,12 +764,10 @@ static NOINLINE int send_select(uint32_t xid, uint32_t server, uint32_t requeste
  * include that list in all subsequent messages.
  */
         /* Fill in: op, htype, hlen, cookie, chaddr fields,
-         * random xid field (we override it below),
-         * message type option:
+         * xid field, message type option:
          */
         init_packet(&packet, DHCPREQUEST);
 
-        packet.xid = xid;
         udhcp_add_simple_option(&packet, DHCP_REQUESTED_IP, requested);
 
         udhcp_add_simple_option(&packet, DHCP_SERVER_ID, server);
@@ -793,7 +789,7 @@ static NOINLINE int send_select(uint32_t xid, uint32_t server, uint32_t requeste
 
 /* Unicast or broadcast a DHCP renew message */
 /* NOINLINE: limit stack usage in caller */
-static NOINLINE int send_renew(uint32_t xid, uint32_t server, uint32_t ciaddr)
+static NOINLINE int send_renew(uint32_t server, uint32_t ciaddr)
 {
         struct dhcp_packet packet;
 
@@ -812,12 +808,10 @@ static NOINLINE int send_renew(uint32_t xid, uint32_t server, uint32_t ciaddr)
  * replying to the client.
  */
         /* Fill in: op, htype, hlen, cookie, chaddr fields,
-         * random xid field (we override it below),
-         * message type option:
+         * xid field, message type option:
          */
         init_packet(&packet, DHCPREQUEST);
 
-        packet.xid = xid;
         packet.ciaddr = ciaddr;
 
         /* Add options: maxsize,
@@ -839,7 +833,7 @@ static NOINLINE int send_renew(uint32_t xid, uint32_t server, uint32_t ciaddr)
 #if ENABLE_FEATURE_UDHCPC_ARPING
 /* Broadcast a DHCP decline message */
 /* NOINLINE: limit stack usage in caller */
-static NOINLINE int send_decline(/*uint32_t xid,*/ uint32_t server, uint32_t requested)
+static NOINLINE int send_decline(uint32_t server, uint32_t requested)
 {
         struct dhcp_packet packet;
 
@@ -848,14 +842,6 @@ static NOINLINE int send_decline(/*uint32_t xid,*/ uint32_t server, uint32_t req
          */
         init_packet(&packet, DHCPDECLINE);
 
-#if 0
-        /* RFC 2131 says DHCPDECLINE's xid is randomly selected by client,
-         * but in case the server is buggy and wants DHCPDECLINE's xid
-         * to match the xid which started entire handshake,
-         * we use the same xid we used in initial DHCPDISCOVER:
-         */
-        packet.xid = xid;
-#endif
         /* DHCPDECLINE uses "requested ip", not ciaddr, to store offered IP */
         udhcp_add_simple_option(&packet, DHCP_REQUESTED_IP, requested);
 
@@ -1145,6 +1131,7 @@ static void perform_release(uint32_t server_addr, uint32_t requested_ip)
                 temp_addr.s_addr = requested_ip;
                 bb_info_msg("unicasting a release of %s to %s",
                                 inet_ntoa(temp_addr), buffer);
+                client_data.xid = random_xid(); //TODO: can omit?
                 send_release(server_addr, requested_ip); /* unicast */
         }
         bb_simple_info_msg("entering released state");
@@ -1233,7 +1220,6 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv)
         int discover_retries = 3;
         uint32_t server_addr = server_addr; /* for compiler */
         uint32_t requested_ip = 0;
-        uint32_t xid = xid; /* for compiler */
         int packet_num;
         int timeout; /* must be signed */
         int lease_remaining; /* must be signed */
@@ -1458,10 +1444,10 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv)
                                 if (!discover_retries || packet_num < discover_retries) {
                                         if (packet_num == 0) {
                                                 change_listen_mode(LISTEN_RAW);
-                                                xid = random_xid();
+                                                client_data.xid = random_xid();
                                         }
                                         /* broadcast */
-                                        send_discover(xid, requested_ip);
+                                        send_discover(requested_ip);
                                         timeout = discover_timeout;
                                         packet_num++;
                                         continue;
@@ -1495,7 +1481,7 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv)
                         case REQUESTING:
                                 if (packet_num < 3) {
                                         /* send broadcast select packet */
-                                        send_select(xid, server_addr, requested_ip);
+                                        send_select(server_addr, requested_ip);
                                         timeout = discover_timeout;
                                         packet_num++;
                                         continue;
@@ -1526,7 +1512,7 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv)
                          * Anyway, it does recover by eventually failing through
                          * into INIT_SELECTING state.
                          */
-                                        if (send_renew(xid, server_addr, requested_ip) >= 0) {
+                                        if (send_renew(server_addr, requested_ip) >= 0) {
                                                 timeout = discover_timeout;
                                                 packet_num++;
                                                 continue;
@@ -1555,7 +1541,7 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv)
                                  * try to find DHCP server using broadcast */
                                 if (lease_remaining > 0 && packet_num < 3) {
                                         /* send a broadcast renew request */
-                                        send_renew(xid, 0 /*INADDR_ANY*/, requested_ip);
+                                        send_renew(0 /*INADDR_ANY*/, requested_ip);
                                         timeout = discover_timeout;
                                         packet_num++;
                                         continue;
@@ -1648,9 +1634,9 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv)
                                 continue;
                 }
 
-                if (packet.xid != xid) {
+                if (packet.xid != client_data.xid) {
                         log1("xid %x (our is %x)%s",
-                                (unsigned)packet.xid, (unsigned)xid,
+                                (unsigned)packet.xid, (unsigned)client_data.xid,
                                 ", ignoring packet"
                         );
                         continue;
@@ -1779,7 +1765,8 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv)
                                         ) {
                                                 bb_simple_info_msg("offered address is in use "
                                                         "(got ARP reply), declining");
-                                                send_decline(/*xid,*/ server_addr, packet.yiaddr);
+                                                client_data.xid = random_xid(); //TODO: can omit?
+                                                send_decline(server_addr, packet.yiaddr);
 
                                                 if (client_data.state != REQUESTING)
                                                         d4_run_script_deconfig();
@@ -1814,7 +1801,7 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv)
                                 timeout = (unsigned)lease_remaining / 2;
                                 client_data.state = BOUND;
                                 /* make future renew packets use different xid */
-                                /* xid = random_xid(); ...but why bother? */
+                                /* client_data.xid = random_xid(); ...but why bother? */
                                 packet_num = 0;
                                 continue; /* back to main loop */
                         }