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#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <ctype.h>
#include <arpa/inet.h>
#include "dhcpv4.h"
struct known_option
{
int type;
int min_len;
int max_len;
int elem_size;
const char *name;
void (*print)(const struct dhcpv4_option *opt, int elem_size, void (*print)(const char *fmt, ...));
};
static void print_int(const struct dhcpv4_option *opt, int elem_size, void (*print)(const char *fmt, ...));
static void print_uint(const struct dhcpv4_option *opt, int elem_size, void (*print)(const char *fmt, ...));
static void print_ip(const struct dhcpv4_option *opt, int elem_size, void (*print)(const char *fmt, ...));
static void print_str(const struct dhcpv4_option *opt, int elem_size, void (*print)(const char *fmt, ...));
static void print_hex(const struct dhcpv4_option *opt, int elem_size, void (*print)(const char *fmt, ...));
static void print_route(const struct dhcpv4_option *opt, int elem_size, void (*print)(const char *fmt, ...));
static void print_classless_route(const struct dhcpv4_option *opt, int elem_size, void (*print)(const char *fmt, ...));
static void print_message_type(const struct dhcpv4_option *opt, int elem_size, void (*print)(const char *fmt, ...));
static void print_request_list(const struct dhcpv4_option *opt, int elem_size, void (*print)(const char *fmt, ...));
static void print_relay_agent(const struct dhcpv4_option *opt, int elem_size, void (*print)(const char *fmt, ...));
static struct known_option options[] = {
{ 1, 4, 4, 4, "Subnet", print_ip },
{ 2, 4, 4, 4, "Time-Offset", print_int },
{ 3, 4, 255, 4, "Router", print_ip },
{ 4, 4, 255, 4, "Time-Server", print_ip },
{ 5, 4, 255, 4, "Name-Server", print_ip },
{ 6, 4, 255, 4, "DNS", print_ip },
//{ 7, 4, 255, 4, "log-server", print_ip },
//{ 8, 4, 255, 4, "cookie-server", print_ip },
//{ 9, 4, 255, 4, "lpr-server", print_ip },
//{ 10, 4, 255, 4, "impress-server", print_ip },
//{ 11, 4, 255, 4, "resourse-location", print_ip },
{ 12, 1, 255, 1, "Host-Name", print_str },
//{ 13, 4, 255, 4, "impress-server", print_ip },
{ 15, 1, 255, 1, "Domain-Name", print_str },
{ 26, 2, 2, 2, "MTU", print_int },
{ 28, 4, 4, 4, "Broadcast", print_ip },
{ 33, 8, 255, 8, "Route", print_route },
{ 42, 4, 4, 4, "NTP", print_ip },
{ 43, 1, 255, 1, "Vendor-Specific", print_hex },
{ 50, 4, 4, 4, "Request-IP", print_ip },
{ 51, 4, 4, 4, "Lease-Time", print_uint },
{ 53, 1, 1, 1, "Message-Type", print_message_type },
{ 54, 4, 4, 4, "Server-ID", print_ip },
{ 55, 1, 255, 1, "Request-List", print_request_list },
{ 56, 1, 255, 1, "Message", print_str },
{ 57, 2, 2, 2, "Max-Message-Size", print_uint },
{ 58, 4, 4, 4, "T1", print_uint },
{ 59, 4, 4, 4, "T2", print_uint },
{ 60, 1, 255, 1, "Vendor-Class", print_hex },
{ 61, 2, 255, 1, "Client-ID", print_hex },
{ 82, 3, 255, 1, "Relay-Agent", print_relay_agent },
{ 121, 5, 255, 1, "Classless-Route", print_classless_route },
{ 0 },
};
int dhcpv4_check_options(struct dhcpv4_packet *pack)
{
struct dhcpv4_option *opt;
struct known_option *kopt;
list_for_each_entry(opt, &pack->options, entry) {
for (kopt = options; kopt->type; kopt++) {
if (kopt->type != opt->type)
continue;
if (opt->len < kopt->min_len)
return -1;
if (opt->len > kopt->max_len)
return -1;
if (opt->len % kopt->elem_size != 0)
return -1;
break;
}
}
return 0;
}
void dhcpv4_print_options(struct dhcpv4_packet *pack, void (*print)(const char *fmt, ...))
{
struct dhcpv4_option *opt;
struct known_option *kopt;
int n = 0;
list_for_each_entry(opt, &pack->options, entry) {
if (n)
print(" <");
else
print("<");
n++;
for (kopt = options; kopt->type && kopt->type != opt->type; kopt++);
if (kopt->type) {
print("%s ", kopt->name);
kopt->print(opt, kopt->elem_size, print);
} else {
print("Option-%i ", opt->type);
print_hex(opt, 1, print);
}
print(">");
}
}
static void print_int(const struct dhcpv4_option *opt, int elem_size, void (*print)(const char *fmt, ...))
{
if (opt->len == 2)
print("%i", ntohs(*(int16_t *)(opt->data)));
else
print("%i", ntohl(*(int32_t *)(opt->data)));
}
static void print_uint(const struct dhcpv4_option *opt, int elem_size, void (*print)(const char *fmt, ...))
{
if (opt->len == 2)
print("%u", ntohs(*(uint16_t *)(opt->data)));
else
print("%u", ntohl(*(uint32_t *)(opt->data)));
}
static void print_ip(const struct dhcpv4_option *opt, int elem_size, void (*print)(const char *fmt, ...))
{
int i, n = opt->len / elem_size;
uint32_t ip;
for (i = 0; i < n; i++) {
ip = ntohl(*(uint32_t *)(opt->data + i*elem_size));
if (i)
print(",");
print("%i.%i.%i.%i",
(ip >> 24) & 0xff,
(ip >> 16) & 0xff,
(ip >> 8) & 0xff,
ip & 0xff);
}
}
static void print_str(const struct dhcpv4_option *opt, int elem_size, void (*print)(const char *fmt, ...))
{
const char *ptr = (const char *)opt->data;
const char *endptr = ptr + opt->len;
for(; ptr < endptr; ptr++)
print("%c", *ptr);
}
static void print_hex(const struct dhcpv4_option *opt, int elem_size, void (*print)(const char *fmt, ...))
{
const uint8_t *ptr = opt->data;
const uint8_t *endptr = ptr + opt->len;
for(; ptr < endptr; ptr++)
print("%02x", *ptr);
}
static void print_route(const struct dhcpv4_option *opt, int elem_size, void (*print)(const char *fmt, ...))
{
int i, n = opt->len / 8;
uint32_t ip, gw;
for (i = 0; i < n; i++) {
ip = ntohl(*(uint32_t *)(opt->data + i*8));
gw = ntohl(*(uint32_t *)(opt->data + i*8 + 4));
if (i)
print(",");
print("%i.%i.%i.%i via %i.%i.%i.%i",
(ip >> 24) & 0xff,
(ip >> 16) & 0xff,
(ip >> 8) & 0xff,
ip & 0xff,
(gw >> 24) & 0xff,
(gw >> 16) & 0xff,
(gw >> 8) & 0xff,
gw & 0xff);
}
}
static void print_message_type(const struct dhcpv4_option *opt, int elem_size, void (*print)(const char *fmt, ...))
{
const char *msg_name[] = {"", "Discover", "Offer", "Request", "Decline", "Ack", "Nak", "Release", "Inform"};
print("%s", msg_name[opt->data[0]]);
}
static void print_request_list(const struct dhcpv4_option *opt, int elem_size, void (*print)(const char *fmt, ...))
{
int i;
struct known_option *kopt;
for (i = 0; i < opt->len; i++) {
if (i)
print(",");
for (kopt = options; kopt->type && kopt->type != opt->data[i]; kopt++);
if (kopt->type)
print("%s", kopt->name);
else
print("%i", opt->data[i]);
}
}
static void print_relay_agent(const struct dhcpv4_option *opt, int elem_size, void (*print)(const char *fmt, ...))
{
const uint8_t *ptr = opt->data;
const uint8_t *endptr = ptr + opt->len;
const uint8_t *endptr1;
int type, len;
while (ptr < endptr) {
if (ptr != opt->data)
print(" ");
type = *ptr++;
len = *ptr++;
/*if (ptr + len > endptr) {
print(" invalid");
return;
}*/
if (type == 1)
print("{Agent-Circuit-ID ");
else if (type == 2)
print("{Agent-Remote-ID ");
else
print("{Option-%i ", type);
endptr1 = ptr + len;
for (;ptr < endptr1; ptr++) {
if (!isprint(*ptr)) {
print("_");
break;
}
print("%c", *ptr);
}
for (;ptr < endptr1; ptr++)
print("%02x", *ptr);
print("}");
}
}
static void print_classless_route(const struct dhcpv4_option *opt, int elem_size, void (*print)(const char *fmt, ...))
{
const uint8_t *ptr = opt->data;
const uint8_t *endptr = ptr + opt->len;
int mask, i, mask1 = 0;
uint32_t ip;
uint32_t gw;
while (ptr < endptr) {
if (ptr != opt->data)
print(",");
mask = *ptr++;
ip = ntohl(*(uint32_t *)ptr);
for (i = 0; i < mask; i++)
mask1 |= (1 << (32 - i));
ip &= mask1;
if (mask <= 8)
ptr++;
else if (mask <= 16)
ptr += 2;
else if (mask <= 24)
ptr += 3;
else
ptr += 4;
gw = ntohl(*(uint32_t *)ptr);
ptr += 4;
print("%i.%i.%i.%i/%i via %i.%i.%i.%i",
(ip >> 24) & 0xff,
(ip >> 16) & 0xff,
(ip >> 8) & 0xff,
ip & 0xff,
mask,
(gw >> 24) & 0xff,
(gw >> 16) & 0xff,
(gw >> 8) & 0xff,
gw & 0xff);
}
}
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