pruebas/c/net/main.c

   1 #include "net.h"
   2 #include "eth.h"
   3 #include "ip.h"
   4 #include "udp.h"
   5 #include <stdio.h>
   6 #include <string.h>
   7 #include <sys/types.h>
   8 #include <sys/socket.h>
   9 #include <netpacket/packet.h>
  10 #include <net/ethernet.h>
  11 #include <sys/ioctl.h>
  12 #include <net/if.h>
  13 #include <netinet/in.h>
  14 #include <unistd.h>
  15
  16 int main()
  17 {
  18         int s = socket(PF_PACKET, SOCK_RAW, htons(ETH_P_IP));
  19         int opt = 1;
  20         struct sockaddr_ll sll;
  21         socklen_t sll_len = sizeof(sll);
  22         struct ifreq ifr;
  23         //struct sockaddr_in sin;
  24         if (setsockopt(s, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt)))
  25         {
  26                 perror("setsockopt()");
  27                 return 3;
  28         }
  29         memset(&ifr, 0, sizeof(ifr));
  30         strncpy(ifr.ifr_name, "eth0", sizeof(ifr));
  31         if (ioctl(s, SIOCGIFINDEX, &ifr) == -1)
  32         {
  33                 perror("ioctl()");
  34                 return 1;
  35         }
  36         memset(&sll, 0, sizeof(struct sockaddr_ll));
  37         sll.sll_family = AF_PACKET;
  38         sll.sll_halen = 6;
  39         sll.sll_ifindex = ifr.ifr_ifindex;
  40         sll.sll_pkttype = PACKET_HOST; // nada de recibir broadcasts, etc.
  41
  42         // Bind
  43         if (bind(s, (struct sockaddr*)&sll, sizeof(sll)))
  44         {
  45                 perror("bind()");
  46                 return 3;
  47         }
  48
  49 /*
  50         memset(&sin, 0, sizeof(sin));
  51         sin.sin_family = AF_INET;
  52         sin.sin_port = htons(2900);
  53         sin.sin_addr.s_addr = INADDR_ANY;
  54         if (bind(s, (struct sockaddr*)&sin, sizeof(sin)))
  55         {
  56                 perror("bind()");
  57                 return 3;
  58         }
  59 */
  60
  61         // Setup de ethernet
  62         eth_addr_local[0] = 0x00;
  63         eth_addr_local[1] = 0x0c;
  64         eth_addr_local[2] = 0x6e;
  65         eth_addr_local[3] = 0x37;
  66         eth_addr_local[4] = 0x19;
  67         eth_addr_local[5] = 0xbf;
  68         // Setup de IP
  69         ip_addr_local[0] = 0x0a;
  70         ip_addr_local[1] = 0x0a;
  71         ip_addr_local[2] = 0x0a;
  72         ip_addr_local[3] = 0x02;
  73         // Setup de UDP
  74         udp_port_local = WORD(0x0b, 0x54); // 2900
  75
  76         while (1) // escuchamos forever
  77         {
  78                 unsigned int i;
  79                 net_resetrp();
  80                 net_resetwp();
  81                 printf("Recibiendo... "); fflush(stdout);
  82                 //if (recvfrom(s, net_buffer, sizeof(net_buffer), 0,
  83                 //              (struct sockaddr*) &sll, &sll_len) < 0)
  84                 if (recv(s, net_buffer, sizeof(net_buffer), 0) < 0)
  85                 {
  86                         perror("recvfrom()");
  87                         return 2;
  88                 }
  89                 printf("OK!\n");
  90                 if (!eth_read_frame_header())
  91                 {
  92                         printf("Header ethernet inválido: DROP!\n");
  93                         continue;
  94                 }
  95                 if (eth_frame_arp)
  96                 {
  97                         printf("No le damos bola a ARP por ahora: DROP!\n");
  98                         continue;
  99                 }
 100                 if (!ip_read_packet_header())
 101                 {
 102                         printf("Header ip inválido: DROP!\n");
 103                         continue;
 104                 }
 105                 if (ip_proto_icmp)
 106                 {
 107                         printf("No le damos bola a ICMP por ahora: DROP!\n");
 108                         continue;
 109                 }
 110                 if (!udp_read_dgram_header())
 111                 {
 112                         printf("Header udp inválido: DROP!\n");
 113                         continue;
 114                 }
 115                 printf("Payload: ");
 116                 for (i = 0; i < (udp_dgram_len - 8); ++i) // 8 == hdr udp
 117                         printf("0x%02X ", net_getb());
 118                 printf("\n");
 119
 120                 // Como hago echo, y el tamaño de las cabeceras no cambian,
 121                 // basta con sólo reescribir las cabeceras
 122                 eth_write_frame_header();
 123                 ip_write_packet_header();
 124                 udp_write_dgram_header();
 125
 126 #if 0
 127                 // Setup para escribir header eth
 128                 eth_addr_remote[0] = 0x00;
 129                 eth_addr_remote[1] = 0xd0;
 130                 eth_addr_remote[2] = 0x09;
 131                 eth_addr_remote[3] = 0xac;
 132                 eth_addr_remote[4] = 0x32;
 133                 eth_addr_remote[5] = 0xe0;
 134                 eth_frame_arp = 0;
 135                 // Escribo header eth
 136                 eth_write_frame_header();
 137                 // Setup para escribir header ip
 138                 ip_addr_remote[0] = 0x0a;
 139                 ip_addr_remote[1] = 0x0a;
 140                 ip_addr_remote[2] = 0x0a;
 141                 ip_addr_remote[3] = 0x01;
 142                 // TODO para setear el tamaño del paquete habría que poner solo el
 143                 // tamaño del payload de UDP y calcular el resto en base a eso.
 144                 ip_packet_len = 20 + 8 + 5; // ip + udp + "hola"
 145                 ip_proto_icmp = 0;
 146                 // Escribo header ip
 147                 ip_write_packet_header();
 148                 // Setup para escribir header udp
 149                 udp_port_remote = WORD(0x0b, 0x54);
 150                 udp_dgram_len = 8 + 5; // udp + "hola"
 151                 // Escribo header udp
 152                 udp_write_dgram_header();
 153                 // Escribo "hola"
 154                 net_putb(0x68); net_putb(0x6f); net_putb(0x6c); net_putb(0x61);
 155                 net_putb(0x00);
 156 #endif
 157                 // Trato de mandar...
 158                 printf("Mandando a %u.%u.%u.%u:%u (%02X:%02X:%02X:%02X:%02X:%02X)\n",
 159                         ip_addr_remote[0], ip_addr_remote[1], ip_addr_remote[2],
 160                         ip_addr_remote[3], udp_port_remote,
 161                         eth_addr_remote[0], eth_addr_remote[1], eth_addr_remote[2],
 162                         eth_addr_remote[3], eth_addr_remote[4], eth_addr_remote[5]);
 163                 i = 14 /* eth hdr */ + ip_packet_len;
 164                 if (i < 60) // tamaño mínimo de ethernet
 165                         i = 60;
 166                 if (send(s, net_buffer, i, 0) < 0)
 167                 {
 168                         perror("send()");
 169                         return 1;
 170                 }
 171         }
 172         close(s);
 173         return 0;
 174 }
 175