Changeset 3621 in MondoRescue for branches/3.3/mindi-busybox/networking/udhcp/packet.c

Timestamp:

Dec 20, 2016, 4:07:32 PM (7 years ago)

Author:

Bruno Cornec

Message:

New 3?3 banch for incorporation of latest busybox 1.25. Changing minor version to handle potential incompatibilities.

Location:

branches/3.3

Files:

• . (copied) (copied from branches/3.2 )
• mindi-busybox/networking/udhcp/packet.c (modified) (6 diffs)

branches/3.3/mindi-busybox/networking/udhcp/packet.c

@@ -39 +39 @@
         return;
 
-    bb_info_msg(
-        //" op %x"
+    bb_error_msg(
+        //"op %x"
         //" htype %x"
         " hlen %x"
@@ -74 +74 @@
     );
     *bin2hex(buf, (void *) packet->chaddr, sizeof(packet->chaddr)) = '\0';
-    bb_info_msg(" chaddr %s", buf);
+    bb_error_msg("chaddr %s", buf);
 }
 #endif
@@ -86 +86 @@
     bytes = safe_read(fd, packet, sizeof(*packet));
     if (bytes < 0) {
-        log1("Packet read error, ignoring");
+        log1("packet read error, ignoring");
         return bytes; /* returns -1 */
     }
@@ -93 +93 @@
      || packet->cookie != htonl(DHCP_MAGIC)
     ) {
-        bb_info_msg("Packet with bad magic, ignoring");
+        bb_error_msg("packet with bad magic, ignoring");
         return -2;
     }
-    log1("Received a packet");
+    log1("received %s", "a packet");
     udhcp_dump_packet(packet);
 
@@ -144 +144 @@
      * In order to work with those buggy servers,
      * we truncate packets after end option byte.
+     *
+     * However, RFC 1542 says "The IP Total Length and UDP Length
+     * must be large enough to contain the minimal BOOTP header of 300 octets".
+     * Thus, we retain enough padding to not go below 300 BOOTP bytes.
+     * Some devices have filters which drop DHCP packets shorter than that.
      */
     padding = DHCP_OPTIONS_BUFSIZE - 1 - udhcp_end_option(packet.data.options);
+    if (padding > DHCP_SIZE - 300)
+        padding = DHCP_SIZE - 300;
 
     packet.ip.protocol = IPPROTO_UDP;
@@ -216 +223 @@
     udhcp_dump_packet(dhcp_pkt);
     padding = DHCP_OPTIONS_BUFSIZE - 1 - udhcp_end_option(dhcp_pkt->options);
+    if (padding > DHCP_SIZE - 300)
+        padding = DHCP_SIZE - 300;
     result = safe_write(fd, dhcp_pkt, DHCP_SIZE - padding);
     msg = "write";