package/busybox/patches/241-udhcpc-oversized_packets.patch

   1 --- a/networking/udhcp/packet.c
   2 +++ b/networking/udhcp/packet.c
   3 @@ -120,6 +120,10 @@ uint16_t FAST_FUNC udhcp_checksum(void *
   4         return ~sum;
   5  }
   6
   7 +int udhcp_get_payload_len(struct dhcpMessage *payload)
   8 +{
   9 +       return sizeof(struct dhcpMessage) - DHCP_OPTIONS_BUFSIZE + end_option(payload->options) + sizeof(payload->options[0]);
  10 +}
  11
  12  /* Construct a ip/udp header for a packet, send packet */
  13  int FAST_FUNC udhcp_send_raw_packet(struct dhcpMessage *payload,
  14 @@ -132,11 +136,7 @@ int FAST_FUNC udhcp_send_raw_packet(stru
  15         int fd;
  16         int result = -1;
  17         const char *msg;
  18 -
  19 -       enum {
  20 -               IP_UPD_DHCP_SIZE = sizeof(struct udp_dhcp_packet) - CONFIG_UDHCPC_SLACK_FOR_BUGGY_SERVERS,
  21 -               UPD_DHCP_SIZE    = IP_UPD_DHCP_SIZE - offsetof(struct udp_dhcp_packet, udp),
  22 -       };
  23 +       int p_len = udhcp_get_payload_len(payload);
  24
  25         fd = socket(PF_PACKET, SOCK_DGRAM, htons(ETH_P_IP));
  26         if (fd < 0) {
  27 @@ -146,7 +146,7 @@ int FAST_FUNC udhcp_send_raw_packet(stru
  28
  29         memset(&dest, 0, sizeof(dest));
  30         memset(&packet, 0, sizeof(packet));
  31 -       packet.data = *payload; /* struct copy */
  32 +       memcpy(&(packet.data), payload, p_len);
  33
  34         dest.sll_family = AF_PACKET;
  35         dest.sll_protocol = htons(ETH_P_IP);
  36 @@ -163,23 +163,18 @@ int FAST_FUNC udhcp_send_raw_packet(stru
  37         packet.ip.daddr = dest_ip;
  38         packet.udp.source = htons(source_port);
  39         packet.udp.dest = htons(dest_port);
  40 -       /* size, excluding IP header: */
  41 -       packet.udp.len = htons(UPD_DHCP_SIZE);
  42 -       /* for UDP checksumming, ip.len is set to UDP packet len */
  43 +       p_len += sizeof(packet.udp);
  44 +       packet.udp.len = htons(p_len);
  45         packet.ip.tot_len = packet.udp.len;
  46 -       packet.udp.check = udhcp_checksum(&packet, IP_UPD_DHCP_SIZE);
  47 -       /* but for sending, it is set to IP packet len */
  48 -       packet.ip.tot_len = htons(IP_UPD_DHCP_SIZE);
  49 +       p_len += sizeof(packet.ip);
  50 +       packet.udp.check = udhcp_checksum(&packet, p_len);
  51 +       packet.ip.tot_len = htons(p_len);
  52         packet.ip.ihl = sizeof(packet.ip) >> 2;
  53         packet.ip.version = IPVERSION;
  54         packet.ip.ttl = IPDEFTTL;
  55         packet.ip.check = udhcp_checksum(&packet.ip, sizeof(packet.ip));
  56
  57 -       /* Currently we send full-sized DHCP packets (zero padded).
  58 -        * If you need to change this: last byte of the packet is
  59 -        * packet.data.options[end_option(packet.data.options)]
  60 -        */
  61 -       result = sendto(fd, &packet, IP_UPD_DHCP_SIZE, 0,
  62 +       result = sendto(fd, &packet, p_len, 0,
  63                                 (struct sockaddr *) &dest, sizeof(dest));
  64         msg = "sendto";
  65   ret_close:
  66 @@ -231,8 +226,7 @@ int FAST_FUNC udhcp_send_kernel_packet(s
  67                 goto ret_close;
  68         }
  69
  70 -       /* Currently we send full-sized DHCP packets (see above) */
  71 -       result = safe_write(fd, payload, DHCP_SIZE);
  72 +       result = safe_write(fd, payload, udhcp_get_payload_len(payload));
  73         msg = "write";
  74   ret_close:
  75         close(fd);