dhcp.c

#include "net/cards.h"
#include "net/dhcp.h"
#include "net/endianess.h"
#include "mem/vmm.h"
#include "lib/rand.h"
#include "net/udp.h"
#include "io/ports.h"
 
void dhcp_discover(netcard_entry_t* card) {
    // DHCP-клиент должен быть готов принять DHCP-сообщение длиной в 576 байт.
 
    dhcp_packet_t* packet = kcalloc(sizeof(dhcp_packet_t), 1);
 
    uint8_t card_mac[6] = {0};
    card->get_mac_addr(card_mac);
 
    packet->op = DHCP_REQUEST;
    packet->hardware_type = 0x01;  // Ethernet
    packet->hardware_addr_len = 0x06;  // Mac address is 6 bytes long
    packet->hops = 0;
    packet->xid = ntohl((size_t)rand());
    packet->seconds = 0;
    packet->flags = htons(0x8000);
    packet->client_ip = 0;
    packet->your_ip = 0;
    packet->server_ip = 0;
    packet->gateway_ip = 0;
 
    memcpy(packet->client_hardware_addr, card_mac, 6);
 
    uint8_t* options_field = packet->options;
 
    *((uint32_t*)options_field) = htonl(0x63825363);
 
    // Discover DHCP
    options_field[4] = 53;
    options_field[5] = 1;
    options_field[6] = 1;
 
    // Address resolution
    options_field[7] = 50;
    options_field[8] = 4;
 
    // Last known IP-Address
    options_field[9] = 0;
    options_field[10] = 0;
    options_field[11] = 0;
    options_field[12] = 0;
 
    // Host name
    options_field[13] = 12;
    options_field[14] = 7;
    options_field[15] = 'S';
    options_field[16] = 'a';
    options_field[17] = 'y';
    options_field[18] = 'o';
    options_field[19] = 'r';
    options_field[20] = 'i';
    options_field[21] = 0;
 
    // End
    options_field[22] = 0xff;
 
    uint8_t dest_ip[4] = {0xff, 0xff, 0xff, 0xff};
 
    qemu_log("DHCP size: %d", sizeof(dhcp_packet_t));
    udp_send_packet(card, dest_ip, 68, 67, packet, sizeof(dhcp_packet_t));
 
    kfree(packet);
}
 
void dhcp_request(netcard_entry_t* card, const uint8_t req_ip[4]) {
    dhcp_packet_t* packet = kcalloc(sizeof(dhcp_packet_t), 1);
 
    uint8_t card_mac[6] = {0};
    card->get_mac_addr(card_mac);
 
    packet->op = DHCP_REQUEST;
    packet->hardware_type = 0x01;  // Ethernet
    packet->hardware_addr_len = 0x06;  // Mac address is 6 bytes long
    packet->hops = 0;
    packet->xid = ntohl((size_t)rand());
    packet->seconds = 0;
    packet->flags = htons(0x8000);
    packet->client_ip = 0;
    packet->your_ip = 0;
    packet->server_ip = 0;
    packet->gateway_ip = 0;
 
    memcpy(packet->client_hardware_addr, card_mac, 6);
 
    uint8_t* options_field = packet->options;
 
    *((uint32_t*)options_field) = htonl(0x63825363);
 
    // Discover DHCP
    options_field[4] = 53;
    options_field[5] = 1;
    options_field[6] = 3;
 
    // Address resolution
    options_field[7] = 50;
    options_field[8] = 4;
 
    // Last known IP-Address
    options_field[9] = req_ip[0];
    options_field[10] = req_ip[1];
    options_field[11] = req_ip[2];
    options_field[12] = req_ip[3];
 
    // Host name
    options_field[13] = 12;
    options_field[14] = 7;
    options_field[15] = 'S';
    options_field[16] = 'a';
    options_field[17] = 'y';
    options_field[18] = 'o';
    options_field[19] = 'r';
    options_field[20] = 'i';
    options_field[21] = 0;
 
    // End
    options_field[22] = 0xff;
 
    uint8_t dest_ip[4] = {0xff, 0xff, 0xff, 0xff};
//  udp_send_packet(card, dest_ip, 68, 67, packet, 576);
 
    qemu_log("DHCP size: %d", sizeof(dhcp_packet_t));
    udp_send_packet(card, dest_ip, 68, 67, packet, sizeof(dhcp_packet_t));
 
    kfree(packet);
}
 
void dhcp_handle_packet(netcard_entry_t* card, dhcp_packet_t* packet) {
    uint8_t* options = packet->options + 4;
 
    char* my_ip = (char*)&packet->your_ip;
    char* sv_ip = (char*)&packet->server_ip;
 
    qemu_log("DHCP");
    qemu_log("Operation: %d", packet->op);
    qemu_log("Client IP: %x", packet->client_ip);
    qemu_log("Your IP: %x (%d.%d.%d.%d)", packet->your_ip, (unsigned char)my_ip[0], (unsigned char)my_ip[1], (unsigned char)my_ip[2], (unsigned char)my_ip[3]);
    qemu_log("Server IP: %x (%d.%d.%d.%d)", packet->server_ip, (unsigned char)sv_ip[0], (unsigned char)sv_ip[1], (unsigned char)sv_ip[2], (unsigned char)sv_ip[3]);
    qemu_log("Gateway IP: %x", packet->gateway_ip);
 
    size_t msgtype = *options;
    qemu_log("First option is: %d", *options);
 
    if(msgtype == 53) {
        uint8_t type = *(options + 2);
 
        if(type == 2) {
            qemu_ok("Request!");
            // Does not work because it executes in IRQ
//          dhcp_request(card, (uint8_t *) &packet->your_ip);
        } else if(type == 5) {
            memcpy(card->ipv4_addr, my_ip, 4);
 
            qemu_ok("Acquired an IP address: %u.%u.%u.%u", card->ipv4_addr[0], card->ipv4_addr[1], card->ipv4_addr[2], card->ipv4_addr[3]);
        }
 
        qemu_log("Type: %d", type);
    }
}
 
void dhcp_init_all_cards() {
    for(int i = 0; i < netcards_get_count(); i++) {
        netcard_entry_t* card = netcard_get(i);
 
        qemu_log("Initializing DHCP for: %s", card->name);
 
        dhcp_discover(card);
        dhcp_request(card, card->ipv4_addr);
    }
}