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);
// printf("DNS packet: id 0x%X flags 0x%X rcode 0x%X qcnt %d ancnt %d nscount %d arcount %d len %d\n",
// 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);
printf("DNS: Q (type 0x%X class 0x%X) for %s\n", my_ntohs(&qf->type), my_ntohs(&qf->class), buff);
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);
// printf("Added A rec to resp. Resp len is %d\n", (rend-reply));
} else if (my_ntohs(&qf->type)==QTYPE_NS) {
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);
// 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);
// 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
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, local_ntohs(&rhdr->ancount)+1);
// printf("Added A rec to resp. Resp len is %d\n", (rend-reply));
} else if (local_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, DNS_LEN-(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, local_ntohs(&rhdr->ancount)+1);
// printf("Added NS rec to resp. Resp len is %d\n", (rend-reply));
} else if (local_ntohs(&qf->type)==QTYPE_URI) {
//Give uri to us
rend=strToLabel(buff, rend, DNS_LEN-(rend-reply)); //Add the label
