I have a little problem with closing task and socket. I found little library to make dns hijack serwer.
My steps
1. call dns_hijack_srv_start to start DNS serwer. (everything works fine - can make TCP connection)
2. call dns_hijack_srv_stop to stop DNS server
3. call dns_hijack_srv_start to start DNS serwer. - and now i cant make TCP connection (httpd_accept_conn: error in accept (23))
Everything works fine also when i just dont stop DNS serwer. I really don't know what is wrong with function dns_hijack_srv_stop.
I'm grateful for any of your help guys!
Code: Select all
#include <string.h>
#include <sys/param.h>
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "esp_log.h"
#include "esp_event.h"
#include "lwip/err.h"
#include "lwip/sockets.h"
#include "lwip/sys.h"
#include <lwip/netdb.h>
#include <byteswap.h>
#include "dns_hijack_srv.h"
static const char *TAG = "KOSA";
#define KOSA_LOG( tag, format, ... ) ESP_LOGE( tag, format, ##__VA_ARGS__)
static dns_hijack_srv_handle_t dns_hijack_srv_handle;
static esp_err_t dns_hijack_srv_cleanup();
static void dns_hijack_srv_task(void *pvParameters) {
uint8_t rx_buffer[128];
for(;;) {
struct sockaddr_in dest_addr;
dest_addr.sin_addr.s_addr = htonl(INADDR_ANY);
dest_addr.sin_family = AF_INET;
dest_addr.sin_port = htons(53);
int sock = dns_hijack_srv_handle.sockfd = socket(AF_INET, SOCK_DGRAM, IPPROTO_IP);
if(sock < 0) {
KOSA_LOG(TAG, "Unable to create socket - Hijacked");
break;
}
KOSA_LOG(TAG, "Socket created - Hijacked");
int err = bind(sock, (struct sockaddr*) &dest_addr, sizeof(dest_addr));
if(err < 0) {
KOSA_LOG(TAG, "Socket unable to bind - Hijacked");
break;
}
KOSA_LOG(TAG, "Listening... - Hijacked");
for(;;) {
struct sockaddr_in source_addr;
socklen_t socklen = sizeof(source_addr);
memset(rx_buffer, 0x00, sizeof(rx_buffer));
int len = recvfrom(sock, rx_buffer, sizeof(rx_buffer), 0, (struct sockaddr*) &source_addr, &socklen);
if(len < 0) {
KOSA_LOG(TAG, "revfrom failed - Hijacked");
break;
}
if(len > DNS_HIJACK_SRV_HEADER_SIZE + DNS_HIJACK_SRV_QUESTION_MAX_LENGTH) {
KOSA_LOG(TAG, "Received more data [%d] than expected. Ignoring. - Hijacked", len);
continue;
}
// Nul termination. To prevent pointer escape
rx_buffer[sizeof(rx_buffer) - 1] = '\0';
dns_header_t *header = (dns_header_t*) rx_buffer;
header->QR = 1;
header->OPCODE = 0;
header->AA = 1;
header->RCODE = 0;
header->TC = 0;
header->Z = 0;
header->RA = 0;
header->ANCOUNT = header->QDCOUNT;
header->NSCOUNT = 0;
header->ARCOUNT = 0;
// ptr points to the beginning of the QUESTION
uint8_t *ptr = rx_buffer + sizeof(dns_header_t);
// Jump over QNAME
while(*ptr++);
// Jump over QTYPE
ptr += 2;
// Jump over QCLASS
ptr += 2;
dns_hijack_answer_t *answer = (dns_hijack_answer_t*) ptr;
answer->NAME = __bswap_16(0xC00C);
answer->TYPE = __bswap_16(1);
answer->CLASS = __bswap_16(1);
answer->TTL = 0;
answer->RDLENGTH = __bswap_16(4);
answer->RDATA = dns_hijack_srv_handle.resolve_ip.addr;
// Jump over ANSWER
ptr += sizeof(dns_hijack_answer_t);
int err = sendto(sock, rx_buffer, ptr - rx_buffer, 0, (struct sockaddr *)&source_addr, sizeof(source_addr));
if (err < 0) {
KOSA_LOG(TAG, "Error occurred during sending - Hijacked");
break;
}
taskYIELD();
}
if(sock != -1) {
dns_hijack_srv_cleanup();
KOSA_LOG(TAG, "Restarting... Hijacked");
}
}
dns_hijack_srv_stop();
}
static esp_err_t dns_hijack_srv_cleanup() {
KOSA_LOG(TAG, "Cleanup - Hijacked");
if(dns_hijack_srv_handle.sockfd != -1) {
shutdown(dns_hijack_srv_handle.sockfd, 0);
close(dns_hijack_srv_handle.sockfd);
KOSA_LOG(TAG, "dns_hijack_closed socket! - Hijacked");
dns_hijack_srv_handle.sockfd = -1;
}
return ESP_OK;
}
esp_err_t dns_hijack_srv_start(const ip4_addr_t resolve_ip_addr) {
if(dns_hijack_srv_handle.task_handle != NULL) {
return ESP_OK;
}
dns_hijack_srv_handle.resolve_ip = resolve_ip_addr;
dns_hijack_srv_handle.sockfd = -1;
KOSA_LOG(TAG, "Resolve IP: "IPSTR,
ip4_addr1(&resolve_ip_addr),
ip4_addr2(&resolve_ip_addr),
ip4_addr3(&resolve_ip_addr),
ip4_addr4(&resolve_ip_addr));
xTaskCreate(dns_hijack_srv_task, "dns_hijack_srv", 4096, NULL, 5, &dns_hijack_srv_handle.task_handle);
return ESP_OK;
}
esp_err_t dns_hijack_srv_stop() {
if (dns_hijack_srv_handle.task_handle != NULL)
{
vTaskDelete(dns_hijack_srv_handle.task_handle);
dns_hijack_srv_handle.task_handle = NULL;
KOSA_LOG(TAG, "vTaskDelate - Hijacked");
}
dns_hijack_srv_cleanup();
KOSA_LOG(TAG, "Server stoped.");
return ESP_OK;
}