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

   1 --- a/networking/udhcp/packet.c
   2 +++ b/networking/udhcp/packet.c
   3 @@ -164,6 +164,11 @@ uint16_t FAST_FUNC udhcp_checksum(void *
   4         return ~sum;
   5  }
   6
   7 +int udhcp_get_payload_len(struct dhcp_packet *dhcp_pkt)
   8 +{
   9 +       return sizeof(struct dhcp_packet) - DHCP_OPTIONS_BUFSIZE + end_option(dhcp_pkt->options) + sizeof(dhcp_pkt->options[0]);
  10 +}
  11 +
  12  /* Construct a ip/udp header for a packet, send packet */
  13  int FAST_FUNC udhcp_send_raw_packet(struct dhcp_packet *dhcp_pkt,
  14                 uint32_t source_ip, int source_port,
  15 @@ -175,11 +180,7 @@ int FAST_FUNC udhcp_send_raw_packet(stru
  16         int fd;
  17         int result = -1;
  18         const char *msg;
  19 -
  20 -       enum {
  21 -               IP_UPD_DHCP_SIZE = sizeof(struct ip_udp_dhcp_packet) - CONFIG_UDHCPC_SLACK_FOR_BUGGY_SERVERS,
  22 -               UPD_DHCP_SIZE    = IP_UPD_DHCP_SIZE - offsetof(struct ip_udp_dhcp_packet, udp),
  23 -       };
  24 +       int p_len = udhcp_get_payload_len(dhcp_pkt);
  25
  26         fd = socket(PF_PACKET, SOCK_DGRAM, htons(ETH_P_IP));
  27         if (fd < 0) {
  28 @@ -189,7 +190,7 @@ int FAST_FUNC udhcp_send_raw_packet(stru
  29
  30         memset(&dest, 0, sizeof(dest));
  31         memset(&packet, 0, sizeof(packet));
  32 -       packet.data = *dhcp_pkt; /* struct copy */
  33 +       memcpy(&(packet.data), dhcp_pkt, p_len);
  34
  35         dest.sll_family = AF_PACKET;
  36         dest.sll_protocol = htons(ETH_P_IP);
  37 @@ -206,24 +207,19 @@ int FAST_FUNC udhcp_send_raw_packet(stru
  38         packet.ip.daddr = dest_ip;
  39         packet.udp.source = htons(source_port);
  40         packet.udp.dest = htons(dest_port);
  41 -       /* size, excluding IP header: */
  42 -       packet.udp.len = htons(UPD_DHCP_SIZE);
  43 -       /* for UDP checksumming, ip.len is set to UDP packet len */
  44 +       p_len += sizeof(packet.udp);
  45 +       packet.udp.len = htons(p_len);
  46         packet.ip.tot_len = packet.udp.len;
  47 -       packet.udp.check = udhcp_checksum(&packet, IP_UPD_DHCP_SIZE);
  48 -       /* but for sending, it is set to IP packet len */
  49 -       packet.ip.tot_len = htons(IP_UPD_DHCP_SIZE);
  50 +       p_len += sizeof(packet.ip);
  51 +       packet.udp.check = udhcp_checksum(&packet, p_len);
  52 +       packet.ip.tot_len = htons(p_len);
  53         packet.ip.ihl = sizeof(packet.ip) >> 2;
  54         packet.ip.version = IPVERSION;
  55         packet.ip.ttl = IPDEFTTL;
  56         packet.ip.check = udhcp_checksum(&packet.ip, sizeof(packet.ip));
  57
  58 -       /* Currently we send full-sized DHCP packets (zero padded).
  59 -        * If you need to change this: last byte of the packet is
  60 -        * packet.data.options[end_option(packet.data.options)]
  61 -        */
  62         udhcp_dump_packet(dhcp_pkt);
  63 -       result = sendto(fd, &packet, IP_UPD_DHCP_SIZE, 0,
  64 +       result = sendto(fd, &packet, p_len, 0,
  65                                 (struct sockaddr *) &dest, sizeof(dest));
  66         msg = "sendto";
  67   ret_close:
  68 @@ -245,10 +241,6 @@ int FAST_FUNC udhcp_send_kernel_packet(s
  69         int result = -1;
  70         const char *msg;
  71
  72 -       enum {
  73 -               DHCP_SIZE = sizeof(struct dhcp_packet) - CONFIG_UDHCPC_SLACK_FOR_BUGGY_SERVERS,
  74 -       };
  75 -
  76         fd = socket(PF_INET, SOCK_DGRAM, IPPROTO_UDP);
  77         if (fd < 0) {
  78                 msg = "socket(%s)";
  79 @@ -274,9 +266,8 @@ int FAST_FUNC udhcp_send_kernel_packet(s
  80                 goto ret_close;
  81         }
  82
  83 -       /* Currently we send full-sized DHCP packets (see above) */
  84         udhcp_dump_packet(dhcp_pkt);
  85 -       result = safe_write(fd, dhcp_pkt, DHCP_SIZE);
  86 +       result = safe_write(fd, dhcp_pkt, udhcp_get_payload_len(dhcp_pkt));
  87         msg = "write";
  88   ret_close:
  89         close(fd);