NRF9160 DNS getaddrinfo error

Question

Hello everyone, 
 I'm trying to connect to my UDP server with only the hostname. 
 I have validate my connection to my UDP server with an IP static and know i want to use an hostname to find my IP and establish a connection to my UDP server. 
 My issue occur when i try to get this IP address. 
 
 I have try an example to establish a connection between my board and my UDP server. To do that i have use this example : Modem Shell 
 I have test this command : sock connect -a "address"' -p 1800 -f inet -t dgram -> All OK 
 After the first command, i have test this one: sock send -i 0 -d testing -> my UDP server correctly receive the message 
 So i have study the code of this example to be able to get the IP address of a specific address. 
 This is my code for the moment : 
 int server_init(void)
{
 int err = -EINVAL;

struct sock_info *socket_info; // = reserve_socket_id();
 if (socket_info == NULL) {
 printk("socket creation failed; MAX SOCKETS exceeeded");
	}

/* Get address */
 
	err = sock_getaddrinfo(socket_info, 1, 2, "myaddress.net", 1800, 0);
	if (err) {
 printk("err get address : %d 
",err);
 //goto connect_error;
	}

printk("OK
");

return 0;
} 
 static int sock_getaddrinfo(
	struct sock_info *socket_info,
	int family,
	int type,
	char *address,
	int port,
	int pdn_cid)
{
	int err;

struct addrinfo hints = {
 .ai_family = 1,
 .ai_socktype = 2,
	};
 
 char pdn_serv[12];
	char *service = NULL;

err = getaddrinfo(address, service, &hints, &socket_info->addrinfo);
 
 if (err) {
 if (err == DNS_EAI_SYSTEM) {
 printk("getaddrinfo() failed, err %d errno %d", err, errno);
 } else {
 printk("getaddrinfo() failed, err %d", err);
 }
 return -EADDRNOTAVAIL;
 }

/* Set port to address info */
 
	((struct sockaddr_in *)socket_info->addrinfo->ai_addr)->sin_port =htons(1800);

return 0;
} 
 My code compile with no problem and after a flash when i debug initialisation of my module, i have this : 
 1) socket creation failed; MAX SOCKETS exceeeded 
 2) getaddrinfo() failed, err -11 errno 115 
 3) err get address : -125" 
 
 I understand the first error, it's because my socket_info is NULL, that not a problem because for the moment i need only 1 socket 
 
 The line where the problem come from is : err = getaddrinfo ( address , service , & hints , & socket_info -> addrinfo ); 
 And i have no idea how to solve this problem, 
 Do you have advice for me ? 
 
 Best regards, 
 Lam

Lamdev · Accepted Answer

Hello, 
 Thanks for your help, 
 I found this solution that works great and come from Modem Shell example and more precisely in in sock folder. 
 I share solution maybe this can help someone. 
 int getIP_fromHost(void){
 
 // struct addrinfo res;
 // struct addrinfo hint;

int err = -EINVAL;

struct sock_info *socket_info = reserve_socket_id();
 if (socket_info == NULL) {
 printk("socket creation failed; MAX SOCKETS exceeeded");
 return 1;
	}

/* Get address */
	err = sock_getaddrinfo(socket_info, 1, 2, "your_udp_server", 1800, 0);
	if (err) {
 printk("err get address : %d 
",err);
 return 1;
	}

char addr_str[INET_ADDRSTRLEN];
 for (struct addrinfo *ai = socket_info->addrinfo; ai != NULL; ai = ai->ai_next) {
 zsock_inet_ntop(ai->ai_family, &((struct sockaddr_in *)ai->ai_addr)->sin_addr, addr_str, sizeof(addr_str));
 printk("IP address: %s
", addr_str);
 }

strcpy(ip_UDPServer,addr_str);
 
 // Clean up.
 freeaddrinfo(socket_info->addrinfo);

return 0;
} 
 static struct sock_info *reserve_socket_id(void)
{
	struct sock_info *socket_info = NULL;
	int socket_id = 0;

	while (socket_id < MAX_SOCKETS) {
 if (!sockets[socket_id].in_use) {
 socket_info = &(sockets[socket_id]);
 //sock_info_clear(socket_info);

 //freeaddrinfo(socket_info->addrinfo);
 memset(socket_info, 0, sizeof(struct sock_info));
 socket_info->id = -1;
 socket_info->fd = -1;
 socket_info->log_receive_data = true;
 socket_info->recv_data_len_expected = -1;
 socket_info->recv_print_format = SOCK_RECV_PRINT_FORMAT_STR;


 socket_info->id = socket_id;
 socket_info->send_info.parent = socket_info;
 break;
 }
 socket_id++;
	}
	return socket_info;
} 
 static int sock_getaddrinfo(struct sock_info *socket_info, int family, int type, char *address, int port, int pdn_cid)
{
	int err;

	struct addrinfo hints = {
 .ai_family = AF_INET, //1
 .ai_socktype = SOCK_DGRAM, //2
 .ai_next = NULL,
 .ai_addr = NULL,
 .ai_protocol = 0 //any protocol
	};
 
 //char pdn_serv[12];
	//char *service = NULL;

	

	err = getaddrinfo(address, NULL, &hints, &socket_info->addrinfo);
 
 if (err) {
 if (err == DNS_EAI_SYSTEM) {
 printk("getaddrinfo() failed, err %d errno %d", err, errno);
 } else {
 printk("getaddrinfo() failed, err %d", err);
 }
 return -EADDRNOTAVAIL;
 }

	/* Set port to address info */
 
	((struct sockaddr_in *)socket_info->addrinfo->ai_addr)->sin_port =htons(1800);
 
	return 0;
} 
 Best reagrds, 
 Lam