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

   1 --- a/networking/udhcp/packet.c
   2 +++ b/networking/udhcp/packet.c
   3 @@ -165,6 +165,11 @@ 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 + udhcp_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_nip, int source_port,
  15 @@ -173,11 +178,12 @@ int FAST_FUNC udhcp_send_raw_packet(stru
  16  {
  17         struct sockaddr_ll dest_sll;
  18         struct ip_udp_dhcp_packet packet;
  19 -       unsigned padding;
  20         int fd;
  21         int result = -1;
  22         const char *msg;
  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                 msg = "socket(%s)";
  29 @@ -186,7 +192,7 @@ int FAST_FUNC udhcp_send_raw_packet(stru
  30
  31         memset(&dest_sll, 0, sizeof(dest_sll));
  32         memset(&packet, 0, offsetof(struct ip_udp_dhcp_packet, data));
  33 -       packet.data = *dhcp_pkt; /* struct copy */
  34 +       memcpy(&(packet.data), dhcp_pkt, p_len);
  35
  36         dest_sll.sll_family = AF_PACKET;
  37         dest_sll.sll_protocol = htons(ETH_P_IP);
  38 @@ -208,27 +214,25 @@ int FAST_FUNC udhcp_send_raw_packet(stru
  39          * In order to work with those buggy servers,
  40          * we truncate packets after end option byte.
  41          */
  42 -       padding = DHCP_OPTIONS_BUFSIZE - 1 - udhcp_end_option(packet.data.options);
  43
  44         packet.ip.protocol = IPPROTO_UDP;
  45         packet.ip.saddr = source_nip;
  46         packet.ip.daddr = dest_nip;
  47         packet.udp.source = htons(source_port);
  48         packet.udp.dest = htons(dest_port);
  49 -       /* size, excluding IP header: */
  50 -       packet.udp.len = htons(UPD_DHCP_SIZE - padding);
  51 -       /* for UDP checksumming, ip.len is set to UDP packet len */
  52 +       p_len += sizeof(packet.udp);
  53 +       packet.udp.len = htons(p_len);
  54         packet.ip.tot_len = packet.udp.len;
  55 -       packet.udp.check = udhcp_checksum(&packet, IP_UPD_DHCP_SIZE - padding);
  56 -       /* but for sending, it is set to IP packet len */
  57 -       packet.ip.tot_len = htons(IP_UPD_DHCP_SIZE - padding);
  58 +       p_len += sizeof(packet.ip);
  59 +       packet.udp.check = udhcp_checksum(&packet, p_len);
  60 +       packet.ip.tot_len = htons(p_len);
  61         packet.ip.ihl = sizeof(packet.ip) >> 2;
  62         packet.ip.version = IPVERSION;
  63         packet.ip.ttl = IPDEFTTL;
  64         packet.ip.check = udhcp_checksum(&packet.ip, sizeof(packet.ip));
  65
  66         udhcp_dump_packet(dhcp_pkt);
  67 -       result = sendto(fd, &packet, IP_UPD_DHCP_SIZE - padding, /*flags:*/ 0,
  68 +       result = sendto(fd, &packet, p_len, 0,
  69                         (struct sockaddr *) &dest_sll, sizeof(dest_sll));
  70         msg = "sendto";
  71   ret_close:
  72 @@ -246,7 +250,6 @@ int FAST_FUNC udhcp_send_kernel_packet(s
  73                 uint32_t dest_nip, int dest_port)
  74  {
  75         struct sockaddr_in client;
  76 -       unsigned padding;
  77         int fd;
  78         int result = -1;
  79         const char *msg;
  80 @@ -278,8 +281,7 @@ int FAST_FUNC udhcp_send_kernel_packet(s
  81
  82         udhcp_dump_packet(dhcp_pkt);
  83
  84 -       padding = DHCP_OPTIONS_BUFSIZE - 1 - udhcp_end_option(dhcp_pkt->options);
  85 -       result = safe_write(fd, dhcp_pkt, DHCP_SIZE - padding);
  86 +       result = safe_write(fd, dhcp_pkt, udhcp_get_payload_len(dhcp_pkt));
  87         msg = "write";
  88   ret_close:
  89         close(fd);