resources/net/ipv4_packet.h

   1 #ifndef _IPV4_PACKET_H_
   2 #define _IPV4_PACKET_H_
   3
   4 #include "libs/array.h"
   5
   6 #include "arch/low/general.h"
   7 #include "packet_builder.h"
   8
   9 namespace net {
  10         class ipv4_packet : public packet_builder {
  11         private:
  12                 enum {
  13                         default_version_size = 0x45,
  14                         default_service = 0,
  15                         default_ttl = 64
  16                 };
  17
  18                 struct packet {
  19                         u8 version_size;
  20                         u8 service;
  21                         u16 length;
  22                         u16 id;
  23                         u16 flags_offset;
  24                         u8 ttl;
  25                         u8 prot;
  26                         u16 checksum;
  27                         u32 src;
  28                         u32 dst;
  29                 } __attribute__((packed));
  30
  31                 mutable p<packet> pkg;
  32
  33                 buffer data;
  34         public:
  35                 ipv4_packet() : pkg(new packet) { }
  36                 ~ipv4_packet() {
  37                         pkg.dispose();
  38                 }
  39
  40                 buffer generate() const {
  41                         /* Set default values */
  42                         pkg->version_size = default_version_size;
  43                         pkg->service = default_service;
  44                         pkg->ttl = default_ttl;
  45                         pkg->flags_offset = to_le16(0x40);
  46
  47                         /* Count packet length */
  48                         pkg->length = to_be16(data.get_size() + sizeof(packet));
  49
  50                         /* Count checksum */
  51                         array<u16> words = array<u16>::from_buffer(buffer::to_mem(pkg));
  52                         u32 sum = 0;
  53                         for (unsigned int i = 0; i < sizeof(packet) / 2; i++)
  54                                 sum += words[i];
  55
  56                         sum = (sum & 0xffff) + (sum >> 16);
  57                         sum += (sum >> 16);
  58
  59                         pkg->checksum = to_le16(~sum);
  60
  61                         buffer buf = buffer::to_mem(pkg);
  62                         buf += data;
  63
  64                         return buf;
  65                 }
  66
  67                 void add_data(const buffer &x) {
  68                         data = x;
  69                 }
  70
  71                 enum protocol {
  72                         p_icmp = 1,
  73                         p_tcp = 6,
  74                         p_udp = 17
  75                 };
  76
  77                 void set_ptype(protocol pt) {
  78                         pkg->prot = pt;
  79                 }
  80
  81                 void set_source_paddr(const ipv4_addr &addr) {
  82                         pkg->src = addr.to_be();
  83                 }
  84
  85                 void set_target_paddr(const ipv4_addr &addr) {
  86                         pkg->dst = addr.to_be();
  87                 }
  88
  89                 ipv4_packet(const buffer &x) : pkg(x.cast<packet>()), data(x) { }
  90
  91                 buffer get_data() const {
  92                         return data.get_next(from_be16(pkg->length)).cut_first(sizeof(packet));
  93                 }
  94
  95                 protocol get_ptype() const {
  96                         return (protocol)pkg->prot;
  97                 }
  98
  99                 ipv4_addr get_source_paddr() const {
 100                         return ipv4_addr::from_be(pkg->src);
 101                 }
 102
 103                 ipv4_addr get_target_paddr() const {
 104                         return ipv4_addr::from_be(pkg->dst);
 105                 }
 106         };
 107 }
 108
 109 #endif