ESP8266 part of the f105-motor-demo project (see f105-motor-demo_stm32)
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9 years ago
/*
* ----------------------------------------------------------------------------
* "THE BEER-WARE LICENSE" (Revision 42):
* Jeroen Domburg <jeroen@spritesmods.com> wrote this file. As long as you retain
* this notice you can do whatever you want with this stuff. If we meet some day,
* and you think this stuff is worth it, you can buy me a beer in return.
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* ----------------------------------------------------------------------------
*/
/*
This is a 'captive portal' DNS server: it basically replies with a fixed IP (in this case:
the one of the SoftAP interface of this ESP module) for any and all DNS queries. This can
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be used to send mobile phones, tablets etc which connect to the ESP in AP mode directly to
the internal webserver.
*/
#include <esp8266.h>
#ifdef FREERTOS
#include "espressif/esp_common.h"
#include "FreeRTOS.h"
#include "task.h"
#include "queue.h"
#include "lwip/sockets.h"
#include "lwip/err.h"
static int sockFd;
#endif
#define DNS_LEN 512
typedef struct __attribute__ ((packed)) {
uint16_t id;
uint8_t flags;
uint8_t rcode;
uint16_t qdcount;
uint16_t ancount;
uint16_t nscount;
uint16_t arcount;
} DnsHeader;
typedef struct __attribute__ ((packed)) {
uint8_t len;
uint8_t data;
} DnsLabel;
typedef struct __attribute__ ((packed)) {
//before: label
uint16_t type;
uint16_t class;
} DnsQuestionFooter;
typedef struct __attribute__ ((packed)) {
//before: label
uint16_t type;
uint16_t class;
uint32_t ttl;
uint16_t rdlength;
//after: rdata
} DnsResourceFooter;
typedef struct __attribute__ ((packed)) {
uint16_t prio;
uint16_t weight;
} DnsUriHdr;
#define FLAG_QR (1<<7)
#define FLAG_AA (1<<2)
#define FLAG_TC (1<<1)
#define FLAG_RD (1<<0)
#define QTYPE_A 1
#define QTYPE_NS 2
#define QTYPE_CNAME 5
#define QTYPE_SOA 6
#define QTYPE_WKS 11
#define QTYPE_PTR 12
#define QTYPE_HINFO 13
#define QTYPE_MINFO 14
#define QTYPE_MX 15
#define QTYPE_TXT 16
#define QTYPE_URI 256
#define QCLASS_IN 1
#define QCLASS_ANY 255
#define QCLASS_URI 256
//Function to put unaligned 16-bit network values
static void ICACHE_FLASH_ATTR setn16(void *pp, int16_t n) {
char *p=pp;
*p++=(char)(n>>8);
*p++=(char)(n&0xff);
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}
//Function to put unaligned 32-bit network values
static void ICACHE_FLASH_ATTR setn32(void *pp, int32_t n) {
char *p=pp;
*p++=(char)((n>>24)&0xff);
*p++=(char)((n>>16)&0xff);
*p++=(char)((n>>8)&0xff);
*p++=(char)(n&0xff);
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}
static uint16_t ICACHE_FLASH_ATTR my_ntohs(uint16_t *in) {
char *p=(char*)in;
return ((p[0]<<8)&0xff00)|(p[1]&0xff);
}
//Parses a label into a C-string containing a dotted
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//Returns pointer to start of next fields in packet
static char* ICACHE_FLASH_ATTR labelToStr(char *packet, char *labelPtr, int packetSz, char *res, int resMaxLen) {
int i, j, k;
char *endPtr=NULL;
i=0;
do {
if ((*labelPtr&0xC0)==0) {
j=*labelPtr++; //skip past length
//Add separator period if there already is data in res
if (i<resMaxLen && i!=0) res[i++]='.';
//Copy label to res
for (k=0; k<j; k++) {
if ((labelPtr-packet)>packetSz) return NULL;
if (i<resMaxLen) res[i++]=*labelPtr++;
}
} else if ((*labelPtr&0xC0)==0xC0) {
//Compressed label pointer
endPtr=labelPtr+2;
int offset=my_ntohs(((uint16_t *)labelPtr))&0x3FFF;
//Check if offset points to somewhere outside of the packet
if (offset>packetSz) return NULL;
labelPtr=&packet[offset];
}
//check for out-of-bound-ness
if ((labelPtr-packet)>packetSz) return NULL;
} while (*labelPtr!=0);
res[i]=0; //zero-terminate
if (endPtr==NULL) endPtr=labelPtr+1;
return endPtr;
}
//Converts a dotted hostname to the weird label form dns uses.
static char ICACHE_FLASH_ATTR *strToLabel(char *str, char *label, int maxLen) {
char *len=label; //ptr to len byte
char *p=label+1; //ptr to next label byte to be written
while (1) {
if (*str=='.' || *str==0) {
*len=(char)((p-len)-1); //write len of label bit
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len=p; //pos of len for next part
p++; //data ptr is one past len
if (*str==0) break; //done
str++;
} else {
*p++=*str++; //copy byte
// if ((p-label)>maxLen) return NULL; //check out of bounds
}
}
*len=0;
return p; //ptr to first free byte in resp
}
//Receive a DNS packet and maybe send a response back
#ifndef FREERTOS
static void ICACHE_FLASH_ATTR captdnsRecv(void* arg, char *pusrdata, unsigned short length) {
struct espconn *conn=(struct espconn *)arg;
#else
static void ICACHE_FLASH_ATTR captdnsRecv(struct sockaddr_in *premote_addr, char *pusrdata, unsigned short length) {
#endif
char buff[DNS_LEN];
char reply[DNS_LEN];
int i;
char *rend=&reply[length];
char *p=pusrdata;
DnsHeader *hdr=(DnsHeader*)p;
DnsHeader *rhdr=(DnsHeader*)&reply[0];
p+=sizeof(DnsHeader);
// httpd_printf("DNS packet: id 0x%X flags 0x%X rcode 0x%X qcnt %d ancnt %d nscount %d arcount %d len %d\n",
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// my_ntohs(&hdr->id), hdr->flags, hdr->rcode, my_ntohs(&hdr->qdcount), my_ntohs(&hdr->ancount), my_ntohs(&hdr->nscount), my_ntohs(&hdr->arcount), length);
//Some sanity checks:
if (length>DNS_LEN) return; //Packet is longer than DNS implementation allows
if (length<sizeof(DnsHeader)) return; //Packet is too short
if (hdr->ancount || hdr->nscount || hdr->arcount) return; //this is a reply, don't know what to do with it
if (hdr->flags&FLAG_TC) return; //truncated, can't use this
//Reply is basically the request plus the needed data
memcpy(reply, pusrdata, length);
rhdr->flags|=FLAG_QR;
for (i=0; i<my_ntohs(&hdr->qdcount); i++) {
//Grab the labels in the q string
p=labelToStr(pusrdata, p, length, buff, sizeof(buff));
if (p==NULL) return;
DnsQuestionFooter *qf=(DnsQuestionFooter*)p;
p+=sizeof(DnsQuestionFooter);
info("DNS: Q (type 0x%X class 0x%X) for %s", my_ntohs(&qf->type), my_ntohs(&qf->class), buff);
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if (my_ntohs(&qf->type)==QTYPE_A) {
//They want to know the IPv4 address of something.
//Build the response.
rend=strToLabel(buff, rend, sizeof(reply)-(rend-reply)); //Add the label
if (rend==NULL) return;
DnsResourceFooter *rf=(DnsResourceFooter *)rend;
rend+=sizeof(DnsResourceFooter);
setn16(&rf->type, QTYPE_A);
setn16(&rf->class, QCLASS_IN);
setn32(&rf->ttl, 0);
setn16(&rf->rdlength, 4); //IPv4 addr is 4 bytes;
//Grab the current IP of the softap interface
struct ip_info info;
wifi_get_ip_info(SOFTAP_IF, &info);
*rend++=ip4_addr1(&info.ip);
*rend++=ip4_addr2(&info.ip);
*rend++=ip4_addr3(&info.ip);
*rend++=ip4_addr4(&info.ip);
setn16(&rhdr->ancount, my_ntohs(&rhdr->ancount)+1);
// httpd_printf("Added A rec to resp. Resp len is %d\n", (rend-reply));
} else if (my_ntohs(&qf->type)==QTYPE_NS) {
//Give ns server. Basically can be whatever we want because it'll get resolved to our IP later anyway.
rend=strToLabel(buff, rend, sizeof(reply)-(rend-reply)); //Add the label
DnsResourceFooter *rf=(DnsResourceFooter *)rend;
rend+=sizeof(DnsResourceFooter);
setn16(&rf->type, QTYPE_NS);
setn16(&rf->class, QCLASS_IN);
setn16(&rf->ttl, 0);
setn16(&rf->rdlength, 4);
*rend++=2;
*rend++='n';
*rend++='s';
*rend++=0;
setn16(&rhdr->ancount, my_ntohs(&rhdr->ancount)+1);
// httpd_printf("Added NS rec to resp. Resp len is %d\n", (rend-reply));
} else if (my_ntohs(&qf->type)==QTYPE_URI) {
//Give uri to us
rend=strToLabel(buff, rend, sizeof(reply)-(rend-reply)); //Add the label
DnsResourceFooter *rf=(DnsResourceFooter *)rend;
rend+=sizeof(DnsResourceFooter);
DnsUriHdr *uh=(DnsUriHdr *)rend;
rend+=sizeof(DnsUriHdr);
setn16(&rf->type, QTYPE_URI);
setn16(&rf->class, QCLASS_URI);
setn16(&rf->ttl, 0);
setn16(&rf->rdlength, 4+16);
setn16(&uh->prio, 10);
setn16(&uh->weight, 1);
memcpy(rend, "http://esp.nonet", 16);
rend+=16;
setn16(&rhdr->ancount, my_ntohs(&rhdr->ancount)+1);
// httpd_printf("Added NS rec to resp. Resp len is %d\n", (rend-reply));
}
}
//Send the response
#ifndef FREERTOS
remot_info *remInfo=NULL;
//Send data to port/ip it came from, not to the ip/port we listen on.
if (espconn_get_connection_info(conn, &remInfo, 0)==ESPCONN_OK) {
conn->proto.udp->remote_port=remInfo->remote_port;
memcpy(conn->proto.udp->remote_ip, remInfo->remote_ip, sizeof(remInfo->remote_ip));
}
espconn_sendto(conn, (uint8*)reply, rend-reply);
#else
sendto(sockFd,(uint8*)reply, rend-reply, 0, (struct sockaddr *)premote_addr, sizeof(struct sockaddr_in));
#endif
}
#ifdef FREERTOS
static void captdnsTask(void *pvParameters) {
struct sockaddr_in server_addr;
int32 ret;
struct sockaddr_in from;
socklen_t fromlen;
struct ip_info ipconfig;
char udp_msg[DNS_LEN];
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memset(&ipconfig, 0, sizeof(ipconfig));
memset(&server_addr, 0, sizeof(server_addr));
server_addr.sin_family = AF_INET;
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server_addr.sin_addr.s_addr = INADDR_ANY;
server_addr.sin_port = htons(53);
server_addr.sin_len = sizeof(server_addr);
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do {
sockFd=socket(AF_INET, SOCK_DGRAM, 0);
if (sockFd==-1) {
httpd_printf("captdns_task failed to create sock!\n");
vTaskDelay(1000/portTICK_RATE_MS);
}
} while (sockFd==-1);
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do {
ret=bind(sockFd, (struct sockaddr *)&server_addr, sizeof(server_addr));
if (ret!=0) {
httpd_printf("captdns_task failed to bind sock!\n");
vTaskDelay(1000/portTICK_RATE_MS);
}
} while (ret!=0);
httpd_printf("CaptDNS inited.\n");
while(1) {
memset(&from, 0, sizeof(from));
fromlen=sizeof(struct sockaddr_in);
ret=recvfrom(sockFd, (u8 *)udp_msg, DNS_LEN, 0,(struct sockaddr *)&from,(socklen_t *)&fromlen);
if (ret>0) captdnsRecv(&from,udp_msg,ret);
}
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close(sockFd);
vTaskDelete(NULL);
}
void captdnsInit(void) {
xTaskCreate(captdnsTask, (const signed char *)"captdns_task", 1200, NULL, 3, NULL);
}
#else
void ICACHE_FLASH_ATTR captdnsInit(void) {
info("Starting captive portal");
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static struct espconn conn;
static esp_udp udpconn;
conn.type=ESPCONN_UDP;
conn.proto.udp=&udpconn;
conn.proto.udp->local_port = 53;
espconn_regist_recvcb(&conn, captdnsRecv);
espconn_create(&conn);
}
#endif