added basic DNS support

master
Martin Ger 2018-06-24 11:19:06 +02:00
rodzic c71a6d1f07
commit a07969e954
7 zmienionych plików z 819 dodań i 9 usunięć

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6d0d78a5dcacc730d09bdaec896fd17ff46c71a5 0x00000.bin
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#include "c_types.h"
#include "mem.h"
#include "ets_sys.h"
#include "osapi.h"
#include "gpio.h"
#include "os_type.h"
#include "lwip/def.h"
#include "user_interface.h"
#include "espconn.h"
#include "dns_responder.h"
//#define DNS_RESP_DEBUG 1
/*
* This software is licensed under the CC0.
*
* This is a _basic_ DNS Server for educational use.
* It does not prevent invalid packets from crashing
* the server.
*
* Originating from:
* https://github.com/mwarning/SimpleDNS
*
*/
LOCAL struct espconn dns_espconn;
struct Message msg;
LOCAL uint8_t dns_mode;
/*
* Masks and constants.
*/
static const uint32_t QR_MASK = 0x8000;
static const uint32_t OPCODE_MASK = 0x7800;
static const uint32_t AA_MASK = 0x0400;
static const uint32_t TC_MASK = 0x0200;
static const uint32_t RD_MASK = 0x0100;
static const uint32_t RA_MASK = 0x8000;
static const uint32_t RCODE_MASK = 0x000F;
/* Response Type */
enum {
Ok_ResponseType = 0,
FormatError_ResponseType = 1,
ServerFailure_ResponseType = 2,
NameError_ResponseType = 3,
NotImplemented_ResponseType = 4,
Refused_ResponseType = 5
};
/* Resource Record Types */
enum {
A_Resource_RecordType = 1,
NS_Resource_RecordType = 2,
CNAME_Resource_RecordType = 5,
SOA_Resource_RecordType = 6,
PTR_Resource_RecordType = 12,
MX_Resource_RecordType = 15,
TXT_Resource_RecordType = 16,
AAAA_Resource_RecordType = 28,
SRV_Resource_RecordType = 33
};
/* Operation Code */
enum {
QUERY_OperationCode = 0, /* standard query */
IQUERY_OperationCode = 1, /* inverse query */
STATUS_OperationCode = 2, /* server status request */
NOTIFY_OperationCode = 4, /* request zone transfer */
UPDATE_OperationCode = 5 /* change resource records */
};
/* Response Code */
enum {
NoError_ResponseCode = 0,
FormatError_ResponseCode = 1,
ServerFailure_ResponseCode = 2,
NameError_ResponseCode = 3
};
/* Query Type */
enum {
IXFR_QueryType = 251,
AXFR_QueryType = 252,
MAILB_QueryType = 253,
MAILA_QueryType = 254,
STAR_QueryType = 255
};
/*
* Types.
*/
/* Question Section */
struct Question {
char *qName;
uint16_t qType;
uint16_t qClass;
struct Question* next; // for linked list
};
/* Data part of a Resource Record */
union ResourceData {
struct {
char *txt_data;
} txt_record;
struct {
uint8_t addr[4];
} a_record;
struct {
char* MName;
char* RName;
uint32_t serial;
uint32_t refresh;
uint32_t retry;
uint32_t expire;
uint32_t minimum;
} soa_record;
struct {
char *name;
} name_server_record;
struct {
char name;
} cname_record;
struct {
char *name;
} ptr_record;
struct {
uint16_t preference;
char *exchange;
} mx_record;
struct {
uint8_t addr[16];
} aaaa_record;
struct {
uint16_t priority;
uint16_t weight;
uint16_t port;
char *target;
} srv_record;
};
/* Resource Record Section */
struct ResourceRecord {
char *name;
uint16_t type;
uint16_t class;
uint16_t ttl;
uint16_t rd_length;
union ResourceData rd_data;
struct ResourceRecord* next; // for linked list
};
struct Message {
uint16_t id; /* Identifier */
/* Flags */
uint16_t qr; /* Query/Response Flag */
uint16_t opcode; /* Operation Code */
uint16_t aa; /* Authoritative Answer Flag */
uint16_t tc; /* Truncation Flag */
uint16_t rd; /* Recursion Desired */
uint16_t ra; /* Recursion Available */
uint16_t rcode; /* Response Code */
uint16_t qdCount; /* Question Count */
uint16_t anCount; /* Answer Record Count */
uint16_t nsCount; /* Authority Record Count */
uint16_t arCount; /* Additional Record Count */
/* At least one question; questions are copied to the response 1:1 */
struct Question* questions;
/*
* Resource records to be send back.
* Every resource record can be in any of the following places.
* But every place has a different semantic.
*/
struct ResourceRecord* answers;
struct ResourceRecord* authorities;
struct ResourceRecord* additionals;
};
/*
int ICACHE_FLASH_ATTR get_A_Record(uint8_t addr[4], const char domain_name[])
{
if (strcmp("foo.bar.com", domain_name) == 0)
{
addr[0] = 192;
addr[1] = 168;
addr[2] = 1;
addr[3] = 1;
return 0;
}
else
{
return -1;
}
}
int ICACHE_FLASH_ATTR get_AAAA_Record(uint8_t addr[16], const char domain_name[])
{
if (strcmp("foo.bar.com", domain_name) == 0)
{
addr[0] = 0xfe;
addr[1] = 0x80;
addr[2] = 0x00;
addr[3] = 0x00;
addr[4] = 0x00;
addr[5] = 0x00;
addr[6] = 0x00;
addr[7] = 0x00;
addr[8] = 0x00;
addr[9] = 0x00;
addr[10] = 0x00;
addr[11] = 0x00;
addr[12] = 0x00;
addr[13] = 0x00;
addr[14] = 0x00;
addr[15] = 0x01;
return 0;
}
else
{
return -1;
}
}
*/
/*
* Debugging functions.
*/
#ifdef DNS_RESP_DEBUG
void ICACHE_FLASH_ATTR print_hex(uint8_t* buf, size_t len)
{
int i;
os_printf("%zu bytes:\n", len);
for(i = 0; i < len; ++i)
os_printf("%02x ", buf[i]);
os_printf("\n");
}
void print_resource_record(struct ResourceRecord* rr)
{
int i;
while (rr)
{
os_printf(" ResourceRecord { name '%s', type %u, class %u, ttl %u, rd_length %u, ",
rr->name,
rr->type,
rr->class,
rr->ttl,
rr->rd_length
);
union ResourceData *rd = &rr->rd_data;
switch (rr->type)
{
case A_Resource_RecordType:
os_printf("Address Resource Record { address ");
for(i = 0; i < 4; ++i)
os_printf("%s%u", (i ? "." : ""), rd->a_record.addr[i]);
os_printf(" }");
break;
case NS_Resource_RecordType:
os_printf("Name Server Resource Record { name %s }",
rd->name_server_record.name
);
break;
case CNAME_Resource_RecordType:
os_printf("Canonical Name Resource Record { name %u }",
rd->cname_record.name
);
break;
case SOA_Resource_RecordType:
os_printf("SOA { MName '%s', RName '%s', serial %u, refresh %u, retry %u, expire %u, minimum %u }",
rd->soa_record.MName,
rd->soa_record.RName,
rd->soa_record.serial,
rd->soa_record.refresh,
rd->soa_record.retry,
rd->soa_record.expire,
rd->soa_record.minimum
);
break;
case PTR_Resource_RecordType:
os_printf("Pointer Resource Record { name '%s' }",
rd->ptr_record.name
);
break;
case MX_Resource_RecordType:
os_printf("Mail Exchange Record { preference %u, exchange '%s' }",
rd->mx_record.preference,
rd->mx_record.exchange
);
break;
case TXT_Resource_RecordType:
os_printf("Text Resource Record { txt_data '%s' }",
rd->txt_record.txt_data
);
break;
case AAAA_Resource_RecordType:
os_printf("AAAA Resource Record { address ");
for(i = 0; i < 16; ++i)
os_printf("%s%02x", (i ? ":" : ""), rd->aaaa_record.addr[i]);
os_printf(" }");
break;
default:
os_printf("Unknown Resource Record { ??? }");
}
os_printf("}\n");
rr = rr->next;
}
}
void ICACHE_FLASH_ATTR print_query(struct Message* msg)
{
os_printf("QUERY { ID: %02x", msg->id);
os_printf(". FIELDS: [ QR: %u, OpCode: %u ]", msg->qr, msg->opcode);
os_printf(", QDcount: %u", msg->qdCount);
os_printf(", ANcount: %u", msg->anCount);
os_printf(", NScount: %u", msg->nsCount);
os_printf(", ARcount: %u,\n", msg->arCount);
struct Question* q = msg->questions;
while (q)
{
os_printf(" Question { qName '%s', qType %u, qClass %u }\n",
q->qName,
q->qType,
q->qClass
);
q = q->next;
}
print_resource_record(msg->answers);
print_resource_record(msg->authorities);
print_resource_record(msg->additionals);
os_printf("}\n");
}
#endif
/*
* Basic memory operations.
*/
size_t ICACHE_FLASH_ATTR get16bits(const uint8_t** buffer)
{
uint16_t value;
os_memcpy(&value, *buffer, 2);
*buffer += 2;
return ntohs(value);
}
void ICACHE_FLASH_ATTR put8bits(uint8_t** buffer, uint8_t value)
{
os_memcpy(*buffer, &value, 1);
*buffer += 1;
}
void ICACHE_FLASH_ATTR put16bits(uint8_t** buffer, uint16_t value)
{
value = htons(value);
os_memcpy(*buffer, &value, 2);
*buffer += 2;
}
void ICACHE_FLASH_ATTR put32bits(uint8_t** buffer, uint32_t value)
{
value = htons(value);
os_memcpy(*buffer, &value, 4);
*buffer += 4;
}
/*
* Deconding/Encoding functions.
*/
// 3foo3bar3com0 => foo.bar.com
char* ICACHE_FLASH_ATTR decode_domain_name(const uint8_t** buffer)
{
char name[256];
const uint8_t* buf = *buffer;
int j = 0;
int i = 0;
while (buf[i] != 0)
{
//if (i >= buflen || i > sizeof(name))
// return NULL;
if (i != 0)
{
name[j] = '.';
j += 1;
}
int len = buf[i];
i += 1;
os_memcpy(name+j, buf+i, len);
i += len;
j += len;
}
name[j] = '\0';
*buffer += i + 1; //also jump over the last 0
//return strdup(name);
uint8_t *ret = os_malloc(os_strlen(name)+1);
os_strcpy(ret, name);
return ret;
}
char ICACHE_FLASH_ATTR *_strchr(const char *s, int c) {
while (*s != (char)c)
if (!*s++)
return 0;
return (char *)s;
}
// foo.bar.com => 3foo3bar3com0
void ICACHE_FLASH_ATTR encode_domain_name(uint8_t** buffer, const char* domain)
{
uint8_t* buf = *buffer;
const char* beg = domain;
const char* pos;
int len = 0;
int i = 0;
while ((pos = _strchr(beg, '.')))
{
len = pos - beg;
buf[i] = len;
i += 1;
os_memcpy(buf+i, beg, len);
i += len;
beg = pos + 1;
}
len = os_strlen(domain) - (beg - domain);
buf[i] = len;
i += 1;
os_memcpy(buf + i, beg, len);
i += len;
buf[i] = 0;
i += 1;
*buffer += i;
}
void ICACHE_FLASH_ATTR decode_header(struct Message* msg, const uint8_t** buffer)
{
msg->id = get16bits(buffer);
uint32_t fields = get16bits(buffer);
msg->qr = (fields & QR_MASK) >> 15;
msg->opcode = (fields & OPCODE_MASK) >> 11;
msg->aa = (fields & AA_MASK) >> 10;
msg->tc = (fields & TC_MASK) >> 9;
msg->rd = (fields & RD_MASK) >> 8;
msg->ra = (fields & RA_MASK) >> 7;
msg->rcode = (fields & RCODE_MASK) >> 0;
msg->qdCount = get16bits(buffer);
msg->anCount = get16bits(buffer);
msg->nsCount = get16bits(buffer);
msg->arCount = get16bits(buffer);
}
void ICACHE_FLASH_ATTR encode_header(struct Message* msg, uint8_t** buffer)
{
put16bits(buffer, msg->id);
int fields = 0;
fields |= (msg->qr << 15) & QR_MASK;
fields |= (msg->rcode << 0) & RCODE_MASK;
// TODO: insert the rest of the fields
put16bits(buffer, fields);
put16bits(buffer, msg->qdCount);
put16bits(buffer, msg->anCount);
put16bits(buffer, msg->nsCount);
put16bits(buffer, msg->arCount);
}
int ICACHE_FLASH_ATTR decode_msg(struct Message* msg, const uint8_t* buffer, int size)
{
int i;
decode_header(msg, &buffer);
if (msg->anCount != 0 || msg->nsCount != 0)
{
os_printf("Only questions expected!\n");
return -1;
}
// parse questions
uint32_t qcount = msg->qdCount;
struct Question* qs = msg->questions;
for (i = 0; i < qcount; ++i)
{
struct Question* q = os_malloc(sizeof(struct Question));
q->qName = decode_domain_name(&buffer);
q->qType = get16bits(&buffer);
q->qClass = get16bits(&buffer);
// prepend question to questions list
q->next = qs;
msg->questions = q;
}
// We do not expect any resource records to parse here.
return 0;
}
// For every question in the message add a appropiate resource record
// in either section 'answers', 'authorities' or 'additionals'.
void ICACHE_FLASH_ATTR resolver_process(struct Message* msg)
{
struct ResourceRecord* beg;
struct ResourceRecord* rr;
struct Question* q;
int rc;
// leave most values intact for response
msg->qr = 1; // this is a response
msg->aa = 1; // this server is authoritative
msg->ra = 0; // no recursion available
msg->rcode = Ok_ResponseType;
// should already be 0
msg->anCount = 0;
msg->nsCount = 0;
msg->arCount = 0;
// for every question append resource records
q = msg->questions;
while (q)
{
rr = os_malloc(sizeof(struct ResourceRecord));
os_memset(rr, 0, sizeof(struct ResourceRecord));
//rr->name = strdup(q->qName);
rr->name = os_malloc(os_strlen(q->qName)+1);
os_strcpy(rr->name, q->qName);
rr->type = q->qType;
rr->class = q->qClass;
rr->ttl = 60*60; // in seconds; 0 means no caching
#ifdef DNS_RESP_DEBUG
os_printf("Query for '%s'\n", q->qName);
#endif
// We only can only answer two question types so far
// and the answer (resource records) will be all put
// into the answers list.
// This behavior is probably non-standard!
switch (q->qType)
{
case A_Resource_RecordType:
rr->rd_length = 4;
rc = get_A_Record(rr->rd_data.a_record.addr, q->qName);
if (rc < 0)
{
os_free(rr->name);
os_free(rr);
goto next;
}
break;
/*
case AAAA_Resource_RecordType:
rr->rd_length = 16;
rc = get_AAAA_Record(rr->rd_data.aaaa_record.addr, q->qName);
if (rc < 0)
{
os_free(rr->name);
os_free(rr);
goto next;
}
break;
*/
/*
case NS_Resource_RecordType:
case CNAME_Resource_RecordType:
case SOA_Resource_RecordType:
case PTR_Resource_RecordType:
case MX_Resource_RecordType:
case TXT_Resource_RecordType:
*/
default:
os_free(rr);
msg->rcode = NotImplemented_ResponseType;
#ifdef DNS_RESP_DEBUG
os_printf("Cannot answer question of type %d.\n", q->qType);
#endif
goto next;
}
msg->anCount++;
// prepend resource record to answers list
beg = msg->answers;
msg->answers = rr;
rr->next = beg;
// jump here to omit question
next:
// process next question
q = q->next;
}
}
/* @return 0 upon failure, 1 upon success */
int ICACHE_FLASH_ATTR encode_resource_records(struct ResourceRecord* rr, uint8_t** buffer)
{
int i;
while (rr)
{
// Answer questions by attaching resource sections.
encode_domain_name(buffer, rr->name);
put16bits(buffer, rr->type);
put16bits(buffer, rr->class);
put32bits(buffer, rr->ttl);
put16bits(buffer, rr->rd_length);
switch (rr->type)
{
case A_Resource_RecordType:
for(i = 0; i < 4; ++i)
put8bits(buffer, rr->rd_data.a_record.addr[i]);
break;
/*
case AAAA_Resource_RecordType:
for(i = 0; i < 16; ++i)
put8bits(buffer, rr->rd_data.aaaa_record.addr[i]);
break;
*/
default:
os_printf("Unknown type %u. => Ignore resource record.\n", rr->type);
return 1;
}
rr = rr->next;
}
return 0;
}
/* @return 0 upon failure, 1 upon success */
int ICACHE_FLASH_ATTR encode_msg(struct Message* msg, uint8_t** buffer)
{
struct Question* q;
int rc;
encode_header(msg, buffer);
q = msg->questions;
while (q)
{
encode_domain_name(buffer, q->qName);
put16bits(buffer, q->qType);
put16bits(buffer, q->qClass);
q = q->next;
}
rc = 0;
rc |= encode_resource_records(msg->answers, buffer);
rc |= encode_resource_records(msg->authorities, buffer);
rc |= encode_resource_records(msg->additionals, buffer);
return rc;
}
void ICACHE_FLASH_ATTR free_resource_records(struct ResourceRecord* rr)
{
struct ResourceRecord* next;
while (rr) {
os_free(rr->name);
next = rr->next;
os_free(rr);
rr = next;
}
}
void ICACHE_FLASH_ATTR free_questions(struct Question* qq)
{
struct Question* next;
while (qq) {
os_free(qq->qName);
next = qq->next;
os_free(qq);
qq = next;
}
}
LOCAL void ICACHE_FLASH_ATTR
user_udp_recv(void *arg, char *pusrdata, unsigned short length)
{
uint8_t hwaddr[6];
uint8_t buffer[1024];
struct ip_info ipconfig;
struct espconn *pespconn = (struct espconn *)arg;
remot_info *premot = NULL;
if (espconn_get_connection_info(pespconn,&premot,0) == ESPCONN_OK){
pespconn->proto.udp->remote_port = premot->remote_port;
pespconn->proto.udp->remote_ip[0] = premot->remote_ip[0];
pespconn->proto.udp->remote_ip[1] = premot->remote_ip[1];
pespconn->proto.udp->remote_ip[2] = premot->remote_ip[2];
pespconn->proto.udp->remote_ip[3] = premot->remote_ip[3];
} else {
return;
}
if (wifi_get_opmode() == STATION_MODE) {
//udp packet is received from ESP8266 station
if (!(dns_mode & DNS_MODE_STA))
return;
} else {
wifi_get_ip_info(SOFTAP_IF, &ipconfig);
wifi_get_macaddr(SOFTAP_IF, hwaddr);
if (!ip_addr_netcmp((struct ip_addr *)pespconn->proto.udp->remote_ip, &ipconfig.ip, &ipconfig.netmask)) {
//udp packet is received from ESP8266 station
if (!(dns_mode & DNS_MODE_STA))
return;
} else {
//udp packet is received from ESP8266 softAP
if (!(dns_mode & DNS_MODE_AP))
return;
}
}
if (pusrdata == NULL)
return;
free_questions(msg.questions);
free_resource_records(msg.answers);
free_resource_records(msg.authorities);
free_resource_records(msg.additionals);
os_memset(&msg, 0, sizeof(struct Message));
if (decode_msg(&msg, pusrdata, length) != 0) {
return;
}
#ifdef DNS_RESP_DEBUG
/* Print query */
print_query(&msg);
#endif
resolver_process(&msg);
#ifdef DNS_RESP_DEBUG
/* Print response */
print_query(&msg);
#endif
uint8_t *p = buffer;
if (encode_msg(&msg, &p) != 0) {
return;
}
espconn_sent(pespconn, buffer, p - buffer);
}
void ICACHE_FLASH_ATTR
dns_resp_init(uint8_t mode)
{
dns_mode = mode;
dns_espconn.type = ESPCONN_UDP;
dns_espconn.proto.udp = (esp_udp *)os_zalloc(sizeof(esp_udp));
dns_espconn.proto.udp->local_port = 53; // DNS udp port
espconn_regist_recvcb(&dns_espconn, user_udp_recv); // register a udp packet receiving callback
espconn_create(&dns_espconn); // create udp
}

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@ -0,0 +1,8 @@
#define DNS_MODE_STA 0x01
#define DNS_MODE_AP 0x02
#define DNS_MODE_STATIONAP 0x03
void dns_resp_init(uint8_t mode);
int get_A_Record(uint8_t addr[4], const char domain_name[]);

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@ -1,7 +1,7 @@
#ifndef _USER_CONFIG_
#define _USER_CONFIG_
#define ESP_UBROKER_VERSION "V2.0.3"
#define ESP_UBROKER_VERSION "V2.0.4"
#define WIFI_SSID "ssid"
#define WIFI_PASSWORD "password"
@ -92,7 +92,7 @@
// Define this if you want to have access the DNS responder.
// Experimental feature - not yet tested
//
//#define DNS_RESP 1
#define DNS_RESP 1
//
// Define this to support the "scan" command for AP search

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@ -766,11 +766,6 @@ int ICACHE_FLASH_ATTR get_A_Record(uint8_t addr[4], const char domain_name[])
return -1;
}
}
int ICACHE_FLASH_ATTR get_AAAA_Record(uint8_t addr[16], const char domain_name[])
{
return -1;
}
#endif