forked from Bananymous/banan-os
368 lines
8.4 KiB
C++
368 lines
8.4 KiB
C++
#include <BAN/Debug.h>
|
|
#include <BAN/Endianness.h>
|
|
#include <BAN/IPv4.h>
|
|
#include <BAN/MAC.h>
|
|
#include <BAN/Vector.h>
|
|
|
|
#include <arpa/inet.h>
|
|
#include <fcntl.h>
|
|
#include <net/if.h>
|
|
#include <netinet/in.h>
|
|
#include <stdio.h>
|
|
#include <stdlib.h>
|
|
#include <string.h>
|
|
#include <stropts.h>
|
|
#include <sys/socket.h>
|
|
|
|
#define DEBUG_DHCP 1
|
|
|
|
struct DHCPPacket
|
|
{
|
|
uint8_t op;
|
|
uint8_t htype { 0x01 };
|
|
uint8_t hlen { 0x06 };
|
|
uint8_t hops { 0x00 };
|
|
BAN::NetworkEndian<uint32_t> xid { 0x3903F326 };
|
|
BAN::NetworkEndian<uint16_t> secs { 0x0000 };
|
|
BAN::NetworkEndian<uint16_t> flags { 0x0000 };
|
|
BAN::IPv4Address ciaddr { 0 };
|
|
BAN::IPv4Address yiaddr { 0 };
|
|
BAN::IPv4Address siaddr { 0 };
|
|
BAN::IPv4Address giaddr { 0 };
|
|
BAN::MACAddress chaddr;
|
|
uint8_t padding[10] {};
|
|
uint8_t legacy[192] {};
|
|
BAN::NetworkEndian<uint32_t> magic_cookie { 0x63825363 };
|
|
uint8_t options[0x100];
|
|
};
|
|
static_assert(offsetof(DHCPPacket, options) == 240);
|
|
|
|
enum DHCPType
|
|
{
|
|
SubnetMask = 1,
|
|
Router = 3,
|
|
DomainNameServer = 6,
|
|
RequestedIPv4Address= 50,
|
|
DHCPMessageType = 53,
|
|
ServerIdentifier = 54,
|
|
ParameterRequestList = 55,
|
|
End = 255,
|
|
};
|
|
|
|
enum DHCPMessageType
|
|
{
|
|
INVALID = 0,
|
|
DHCPDISCOVER = 1,
|
|
DHCPOFFER = 2,
|
|
DHCPREQUEST = 3,
|
|
DHCPDECLINE = 4,
|
|
DHCPACK = 5,
|
|
};
|
|
|
|
BAN::MACAddress get_mac_address(int socket)
|
|
{
|
|
ifreq ifreq;
|
|
if (ioctl(socket, SIOCGIFHWADDR, &ifreq) == -1)
|
|
{
|
|
perror("ioctl");
|
|
exit(1);
|
|
}
|
|
|
|
BAN::MACAddress mac_address;
|
|
memcpy(&mac_address, ifreq.ifr_ifru.ifru_hwaddr.sa_data, sizeof(mac_address));
|
|
return mac_address;
|
|
}
|
|
|
|
void update_ipv4_info(int socket, BAN::IPv4Address address, BAN::IPv4Address subnet)
|
|
{
|
|
{
|
|
ifreq ifreq;
|
|
auto& ifru_addr = *reinterpret_cast<sockaddr_in*>(&ifreq.ifr_ifru.ifru_addr);
|
|
ifru_addr.sin_family = AF_INET;
|
|
ifru_addr.sin_addr.s_addr = address.raw;
|
|
if (ioctl(socket, SIOCSIFADDR, &ifreq) == -1)
|
|
{
|
|
perror("ioctl");
|
|
exit(1);
|
|
}
|
|
}
|
|
|
|
{
|
|
ifreq ifreq;
|
|
auto& ifru_netmask = *reinterpret_cast<sockaddr_in*>(&ifreq.ifr_ifru.ifru_netmask);
|
|
ifru_netmask.sin_family = AF_INET;
|
|
ifru_netmask.sin_addr.s_addr = netmask.raw;
|
|
if (ioctl(socket, SIOCSIFNETMASK, &ifreq) == -1)
|
|
{
|
|
perror("ioctl");
|
|
exit(1);
|
|
}
|
|
}
|
|
}
|
|
|
|
void send_dhcp_packet(int socket, const DHCPPacket& dhcp_packet, BAN::IPv4Address server_ipv4)
|
|
{
|
|
sockaddr_in server_addr;
|
|
server_addr.sin_family = AF_INET;
|
|
server_addr.sin_port = htons(67);
|
|
server_addr.sin_addr.s_addr = server_ipv4.raw;
|
|
|
|
if (sendto(socket, &dhcp_packet, sizeof(DHCPPacket), 0, (sockaddr*)&server_addr, sizeof(server_addr)) == -1)
|
|
{
|
|
perror("sendto");
|
|
exit(1);
|
|
}
|
|
}
|
|
|
|
void send_dhcp_discover(int socket, BAN::MACAddress mac_address)
|
|
{
|
|
DHCPPacket dhcp_packet;
|
|
dhcp_packet.op = 0x01;
|
|
dhcp_packet.chaddr = mac_address;
|
|
|
|
size_t idx = 0;
|
|
|
|
dhcp_packet.options[idx++] = DHCPMessageType;
|
|
dhcp_packet.options[idx++] = 0x01;
|
|
dhcp_packet.options[idx++] = DHCPDISCOVER;
|
|
|
|
dhcp_packet.options[idx++] = ParameterRequestList;
|
|
dhcp_packet.options[idx++] = 0x03;
|
|
dhcp_packet.options[idx++] = DomainNameServer;
|
|
dhcp_packet.options[idx++] = SubnetMask;
|
|
dhcp_packet.options[idx++] = Router;
|
|
|
|
dhcp_packet.options[idx++] = 0xFF;
|
|
|
|
send_dhcp_packet(socket, dhcp_packet, BAN::IPv4Address { 0xFFFFFFFF });
|
|
}
|
|
|
|
void send_dhcp_request(int socket, BAN::MACAddress mac_address, BAN::IPv4Address offered_ipv4, BAN::IPv4Address server_ipv4)
|
|
{
|
|
DHCPPacket dhcp_packet;
|
|
dhcp_packet.op = 0x01;
|
|
dhcp_packet.siaddr = server_ipv4.raw;
|
|
dhcp_packet.chaddr = mac_address;
|
|
|
|
size_t idx = 0;
|
|
|
|
dhcp_packet.options[idx++] = DHCPMessageType;
|
|
dhcp_packet.options[idx++] = 0x01;
|
|
dhcp_packet.options[idx++] = DHCPREQUEST;
|
|
|
|
dhcp_packet.options[idx++] = RequestedIPv4Address;
|
|
dhcp_packet.options[idx++] = 0x04;
|
|
dhcp_packet.options[idx++] = offered_ipv4.octets[0];
|
|
dhcp_packet.options[idx++] = offered_ipv4.octets[1];
|
|
dhcp_packet.options[idx++] = offered_ipv4.octets[2];
|
|
dhcp_packet.options[idx++] = offered_ipv4.octets[3];
|
|
|
|
dhcp_packet.options[idx++] = 0xFF;
|
|
|
|
send_dhcp_packet(socket, dhcp_packet, BAN::IPv4Address { 0xFFFFFFFF });
|
|
}
|
|
|
|
struct DHCPPacketInfo
|
|
{
|
|
enum DHCPMessageType message_type { INVALID };
|
|
BAN::IPv4Address address { 0 };
|
|
BAN::IPv4Address subnet { 0 };
|
|
BAN::IPv4Address server { 0 };
|
|
BAN::Vector<BAN::IPv4Address> routers;
|
|
BAN::Vector<BAN::IPv4Address> dns;
|
|
};
|
|
|
|
DHCPPacketInfo parse_dhcp_packet(const DHCPPacket& packet)
|
|
{
|
|
DHCPPacketInfo packet_info;
|
|
packet_info.address = BAN::IPv4Address(packet.yiaddr);
|
|
|
|
const uint8_t* options = packet.options;
|
|
while (*options != End)
|
|
{
|
|
uint8_t type = *options++;
|
|
uint8_t length = *options++;
|
|
|
|
switch (type)
|
|
{
|
|
case SubnetMask:
|
|
{
|
|
if (length != 4)
|
|
{
|
|
fprintf(stderr, "Subnet mask with invalid length %hhu\n", length);
|
|
break;
|
|
}
|
|
uint32_t raw = *reinterpret_cast<const uint32_t*>(options);
|
|
packet_info.subnet = BAN::IPv4Address(raw);
|
|
break;
|
|
}
|
|
case Router:
|
|
{
|
|
if (length % 4 != 0)
|
|
{
|
|
fprintf(stderr, "Router with invalid length %hhu\n", length);
|
|
break;
|
|
}
|
|
for (int i = 0; i < length; i += 4)
|
|
{
|
|
uint32_t raw = *reinterpret_cast<const uint32_t*>(options + i);
|
|
MUST(packet_info.routers.emplace_back(raw));
|
|
}
|
|
break;
|
|
}
|
|
case DomainNameServer:
|
|
{
|
|
if (length % 4 != 0)
|
|
{
|
|
fprintf(stderr, "DNS with invalid length %hhu\n", length);
|
|
break;
|
|
}
|
|
for (int i = 0; i < length; i += 4)
|
|
{
|
|
uint32_t raw = *reinterpret_cast<const uint32_t*>(options + i);
|
|
MUST(packet_info.dns.emplace_back(raw));
|
|
}
|
|
break;
|
|
}
|
|
case DHCPMessageType:
|
|
{
|
|
if (length != 1)
|
|
{
|
|
fprintf(stderr, "DHCP Message Type with invalid length %hhu\n", length);
|
|
break;
|
|
}
|
|
switch (*options)
|
|
{
|
|
case DHCPDISCOVER: packet_info.message_type = DHCPDISCOVER; break;
|
|
case DHCPOFFER: packet_info.message_type = DHCPOFFER; break;
|
|
case DHCPREQUEST: packet_info.message_type = DHCPREQUEST; break;
|
|
case DHCPDECLINE: packet_info.message_type = DHCPDECLINE; break;
|
|
case DHCPACK: packet_info.message_type = DHCPACK; break;
|
|
}
|
|
break;
|
|
}
|
|
case ServerIdentifier:
|
|
{
|
|
if (length != 4)
|
|
{
|
|
fprintf(stderr, "Server identifier with invalid length %hhu\n", length);
|
|
break;
|
|
}
|
|
uint32_t raw = *reinterpret_cast<const uint32_t*>(options);
|
|
packet_info.server = BAN::IPv4Address(raw);
|
|
break;
|
|
}
|
|
}
|
|
|
|
options += length;
|
|
}
|
|
|
|
return packet_info;
|
|
}
|
|
|
|
BAN::Optional<DHCPPacketInfo> read_dhcp_packet(int socket)
|
|
{
|
|
DHCPPacket dhcp_packet;
|
|
|
|
ssize_t nrecv = recvfrom(socket, &dhcp_packet, sizeof(dhcp_packet), 0, nullptr, nullptr);
|
|
if (nrecv == -1)
|
|
{
|
|
perror("revcfrom");
|
|
return {};
|
|
}
|
|
|
|
if (nrecv <= (ssize_t)offsetof(DHCPPacket, options))
|
|
{
|
|
fprintf(stderr, "invalid DHCP offer\n");
|
|
return {};
|
|
}
|
|
|
|
if (dhcp_packet.magic_cookie != 0x63825363)
|
|
{
|
|
fprintf(stderr, "invalid DHCP offer\n");
|
|
return {};
|
|
}
|
|
|
|
return parse_dhcp_packet(dhcp_packet);
|
|
}
|
|
|
|
int main()
|
|
{
|
|
int socket = ::socket(AF_INET, SOCK_DGRAM, 0);
|
|
if (socket == -1)
|
|
{
|
|
perror("socket");
|
|
return 1;
|
|
}
|
|
|
|
sockaddr_in client_addr;
|
|
client_addr.sin_family = AF_INET;
|
|
client_addr.sin_port = htons(68);
|
|
client_addr.sin_addr.s_addr = INADDR_ANY;
|
|
|
|
if (bind(socket, (sockaddr*)&client_addr, sizeof(client_addr)) == -1)
|
|
{
|
|
perror("bind");
|
|
return 1;
|
|
}
|
|
|
|
auto mac_address = get_mac_address(socket);
|
|
#if DEBUG_DHCP
|
|
dprintln("MAC: {}", mac_address);
|
|
#endif
|
|
|
|
send_dhcp_discover(socket, mac_address);
|
|
#if DEBUG_DHCP
|
|
dprintln("DHCPDISCOVER sent");
|
|
#endif
|
|
|
|
auto dhcp_offer = read_dhcp_packet(socket);
|
|
if (!dhcp_offer.has_value())
|
|
return 1;
|
|
if (dhcp_offer->message_type != DHCPOFFER)
|
|
{
|
|
fprintf(stderr, "DHCP server did not respond with DHCPOFFER\n");
|
|
return 1;
|
|
}
|
|
|
|
#if DEBUG_DHCP
|
|
dprintln("DHCPOFFER");
|
|
dprintln(" IP {}", dhcp_offer->address);
|
|
dprintln(" SUBNET {}", dhcp_offer->subnet);
|
|
dprintln(" SERVER {}", dhcp_offer->server);
|
|
#endif
|
|
|
|
send_dhcp_request(socket, mac_address, dhcp_offer->address, dhcp_offer->server);
|
|
#if DEBUG_DHCP
|
|
dprintln("DHCPREQUEST sent");
|
|
#endif
|
|
|
|
auto dhcp_ack = read_dhcp_packet(socket);
|
|
if (!dhcp_ack.has_value())
|
|
return 1;
|
|
if (dhcp_ack->message_type != DHCPACK)
|
|
{
|
|
fprintf(stderr, "DHCP server did not respond with DHCPACK\n");
|
|
return 1;
|
|
}
|
|
|
|
#if DEBUG_DHCP
|
|
dprintln("DHCPACK");
|
|
dprintln(" IP {}", dhcp_ack->address);
|
|
dprintln(" SUBNET {}", dhcp_ack->subnet);
|
|
dprintln(" SERVER {}", dhcp_ack->server);
|
|
#endif
|
|
|
|
if (dhcp_offer->address != dhcp_ack->address)
|
|
{
|
|
fprintf(stderr, "DHCP server OFFER and ACK ips don't match\n");
|
|
return 1;
|
|
}
|
|
|
|
update_ipv4_info(socket, dhcp_ack->address, dhcp_ack->subnet);
|
|
|
|
close(socket);
|
|
|
|
return 0;
|
|
}
|