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dns: FIX add README_API file and improve sample code

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README_API file is added in this patch.

Inline code documentation is improved. More test domains are added.
The README file is also updated to reflect these changes.

Change-Id: Ie670a6559611c6a8d216470e245dbea48369696f
Signed-off-by: Flavio Santes <flavio.santes@intel.com>
This commit is contained in:
Flavio Santes 2016-08-04 11:21:34 -05:00 • committed by Inaky Perez-Gonzalez
commit 0aa191389c
3 changed files with 145 additions and 78 deletions
Download patch file Download diff file Expand all files Collapse all files

119
samples/net/dns_client/README
View file

@ -1,5 +1,6 @@
DNS Client Application
Requirements
------------
@ -11,8 +12,9 @@ Requirements
* dnsmasq application. The dnsmasq version used in this sample is:
dnsmasq -v
Dnsmasq version 2.75 Copyright (c) 2000-2015 Simon Kelley
dnsmasq -v
Dnsmasq version 2.75 Copyright (c) 2000-2015 Simon Kelley
Building instructions
---------------------
@ -34,69 +36,104 @@ Usage
* Open a terminal window and type:
dnsmasq -d
dnsmasq -d
* Connect the USB-UART cable to the Galileo. Open a terminal and run:
screen /dev/ttyUSB0 115200
screen /dev/ttyUSB0 115200
* Connect Galileo to the LAN, Turn on the board.
* The screen terminal window will show:
WARNING: no console will be available to OS
error: no suitable video mode found.
-----------------------------------------
Domain name: not_a_real_domain_name
[fiber:82] DNS Create Query: 0, ID: 1
[fiber:85] TX: 0
[fiber:88] RX: -5
[fiber:89] DNS Query: OK, ID: 0
[fiber:92] TX: OK
[fiber:97] RX: OK
[fiber:102] DNS Response: ERROR <- :)
-----------------------------------------
Domain name: oops!
[fiber:82] DNS Create Query: 0, ID: 2
[fiber:85] TX: 0
[fiber:88] RX: 0
[fiber:95] DNS response: 2
-----------------------------------------
Domain name: zephyrproject.org
[fiber:82] DNS Create Query: 0, ID: 3
[fiber:85] TX: 0
[fiber:88] RX: 0
Domain name: linuxfoundation.org
[fiber:89] DNS Query: OK, ID: 1
[fiber:92] TX: OK
[fiber:97] RX: OK
****** DNS ANSWER: 0 ******
Response: IP address Size: 4: 140 211 169 8
[fiber:95] DNS response: 0
Response: IP address Size: 4: 140 211 169 4
[fiber:102] DNS Response: OK
-----------------------------------------
Domain name: www.google.com
[fiber:82] DNS Create Query: 0, ID: 4
[fiber:85] TX: 0
[fiber:88] RX: 0
Domain name: www.linuxfoundation.org
[fiber:89] DNS Query: OK, ID: 2
[fiber:92] TX: OK
[fiber:97] RX: OK
****** DNS ANSWER: 0 ******
Response: IP address Size: 4: 216 58 192 4
[fiber:95] DNS response: 0
Response: IP address Size: 4: 140 211 169 4
[fiber:102] DNS Response: OK
-----------------------------------------
Domain name: mail.yahoo.com
[fiber:82] DNS Create Query: 0, ID: 5
[fiber:85] TX: 0
[fiber:88] RX: 0
Domain name: gnu.org
[fiber:89] DNS Query: OK, ID: 3
[fiber:92] TX: OK
[fiber:97] RX: OK
****** DNS ANSWER: 0 ******
Response: CNAME NO IP address Size: 8: 5 108 111 103 105 110 192 17
CNAME: login.yahoo.com
Response: IP address Size: 4: 208 118 235 148
[fiber:102] DNS Response: OK
-----------------------------------------
Domain name: www.gnu.org
[fiber:89] DNS Query: OK, ID: 4
[fiber:92] TX: OK
[fiber:97] RX: OK
****** DNS ANSWER: 0 ******
Response: CNAME NO IP address
CNAME: wildebeest.gnu.org
****** DNS ANSWER: 1 ******
Response: CNAME NO IP address Size: 35: 9 102 111 45 100 115 45 97 116 115 6 109 101 109 98 101 114 3 103 48 50 8 121 97 104 111 111 100 110 115 3 110 101 116 0
CNAME: fo-ds-ats.member.g02.yahoodns.net
Response: IP address Size: 4: 208 118 235 148
****** DNS ANSWER: 2 ******
Response: IP address Size: 4: 98 136 189 41
[fiber:95] DNS response: 0
[fiber:102] DNS Response: OK
-----------------------------------------
Bye!
Domain name: npr.org
[fiber:89] DNS Query: OK, ID: 5
[fiber:92] TX: OK
[fiber:97] RX: OK
****** DNS ANSWER: 0 ******
Response: IP address Size: 4: 216 35 221 76
[fiber:102] DNS Response: OK
-----------------------------------------
Domain name: www.npr.org
[fiber:89] DNS Query: OK, ID: 6
[fiber:92] TX: OK
[fiber:97] RX: OK
****** DNS ANSWER: 0 ******
Response: CNAME NO IP address
CNAME: www-cdn.npr.org.edgesuite.net
****** DNS ANSWER: 1 ******
Response: CNAME NO IP address
CNAME: a1723.g.akamai.net
****** DNS ANSWER: 2 ******
Response: IP address Size: 4: 63 80 4 192
****** DNS ANSWER: 3 ******
Response: IP address Size: 4: 63 80 4 161
[fiber:102] DNS Response: OK

23
samples/net/dns_client/README_API Normal file
View file

@ -0,0 +1,23 @@
DNS Client API
-----------------------------------------------------------------------
THIS API IS STILL WORK IN PROGRESS
-----------------------------------------------------------------------
The DNS Client API for Zephyr is a collection of C files:
- dns_pack.h, dns_pack.c:
RFC 1035 serialization and deserialization functions
- dns_utils.h. dns_utils.c:
Helper functions
TODO
- Implement high-level functions to handle the server's response
- Remove:
* dns_query in src/main.c and handle the Transaction
Identifier internally.
* dns_response in src/main.c once high-level functions are
available.

81
samples/net/dns_client/src/main.c
View file

@ -27,19 +27,26 @@
uint8_t stack[STACK_SIZE];
#define BUF_SIZE 1024
uint8_t tx_raw_buf[BUF_SIZE];
uint8_t rx_raw_buf[BUF_SIZE];
#define SLEEP_TIME 10
#define SLEEP_TIME 50
char *domains[] = {"not_a_real_domain_name", "oops!",
"zephyrproject.org", "www.google.com",
"mail.yahoo.com", NULL};
#define RC_STR(rc) (rc == 0 ? "OK" : "ERROR")
char *domains[] = {"not_a_real_domain_name",
"linuxfoundation.org", "www.linuxfoundation.org",
"gnu.org", "www.gnu.org",
"npr.org", "www.npr.org",
"wikipedia.org", "www.wikipedia.org",
"zephyrproject.org", "www.zephyrproject.org",
NULL};
/* this function creates the DNS query */
int dns_query(struct app_buf_t *buf, char *str, uint16_t id,
enum dns_rr_type qtype);
/* this function parses the DNS server response */
int dns_response(struct app_buf_t *_buf, int *response_type, int src_id);
void fiber(void)
@ -50,6 +57,9 @@ void fiber(void)
struct app_buf_t rx_buf = APP_BUF_INIT(rx_raw_buf,
sizeof(rx_raw_buf), 0);
/* If the network is a bit slow, increase rx_timeout and
* tx_retry_timeout in struct netz_ctx_t
*/
struct netz_ctx_t netz_ctx = NETZ_CTX_INIT;
int response_type;
@ -64,41 +74,39 @@ void fiber(void)
counter = 0;
do {
fiber_sleep(300);
printf("\n-----------------------------------------\n");
name = domains[counter];
if (name == NULL) {
counter = 0;
break;
continue;
}
counter += 1;
printf("Domain name: %s\n", name);
rc = dns_query(&tx_buf, name, counter, DNS_RR_TYPE_A);
printf("[%s:%d] DNS Create Query: %d, ID: %d\n",
__func__, __LINE__, rc, counter);
printf("[%s:%d] DNS Query: %s, ID: %d\n",
__func__, __LINE__, RC_STR(rc), counter);
rc = netz_tx(&netz_ctx, &tx_buf);
printf("[%s:%d] TX: %d\n", __func__, __LINE__, rc);
printf("[%s:%d] TX: %s\n", __func__, __LINE__, RC_STR(rc));
fiber_sleep(SLEEP_TIME);
rc = netz_rx(&netz_ctx, &rx_buf);
printf("[%s:%d] RX: %d\n", __func__, __LINE__, rc);
printf("[%s:%d] RX: %s\n", __func__, __LINE__, RC_STR(rc));
if (rc != 0) {
continue;
if (rc == 0) {
rc = dns_response(&rx_buf, &response_type, counter);
printf("[%s:%d] DNS Response: %s %s\n",
__func__, __LINE__, RC_STR(rc),
(rc != 0 && counter == 0 ? "<- :)" : ""));
}
rc = dns_response(&rx_buf, &response_type, counter);
printf("[%s:%d] DNS response: %d\n", __func__, __LINE__, rc);
counter += 1;
fiber_sleep(SLEEP_TIME);
} while (1);
printf("Bye!\n");
}
void main(void)
@ -109,13 +117,18 @@ void main(void)
0, 0, 7, 0);
}
/* Next versions must handle the transaction id internally */
int dns_query(struct app_buf_t *buf, char *str, uint16_t id,
enum dns_rr_type qtype)
{
return dns_msg_pack_query(buf, str, id, qtype);
}
/* See dns_unpack_answer, and also see:
* https://tools.ietf.org/html/rfc1035#section-4.1.2
*/
#define DNS_QUERY_POS 0x0c
int dns_response(struct app_buf_t *_buf, int *response_type, int src_id)
{
struct dns_msg_t dns_msg = DNS_MSG_INIT(_buf->buf, _buf->size);
@ -125,7 +138,7 @@ int dns_response(struct app_buf_t *_buf, int *response_type, int src_id)
rc = dns_unpack_response_header(&dns_msg, src_id);
if (rc != 0) {
return rc;
return -EINVAL;
}
if (dns_header_qdcount(dns_msg.msg) != 1) {
@ -134,20 +147,18 @@ int dns_response(struct app_buf_t *_buf, int *response_type, int src_id)
rc = dns_unpack_response_query(&dns_msg);
if (rc != 0) {
return rc;
return -EINVAL;
}
i = 0;
/* the first dname is at 0x0c bytes */
ptr = 0x0c;
ptr = DNS_QUERY_POS;
while (i < dns_header_ancount(dns_msg.msg)) {
printf("\n****** DNS ANSWER: %d ******\n", i);
rc = dns_unpack_answer(&dns_msg, ptr);
if (rc != 0) {
printf("[%s:%d]\n", __func__, __LINE__);
return rc;
return -EINVAL;
}
switch (dns_msg.response_type) {
@ -156,18 +167,16 @@ int dns_response(struct app_buf_t *_buf, int *response_type, int src_id)
dns_msg.response_length);
print_buf(dns_msg.msg + dns_msg.response_position,
dns_msg.response_length);
printf("\n");
break;
case DNS_RESPONSE_CNAME_NO_IP:
printf("Response: CNAME NO IP address\t\tSize: %d:\t",
dns_msg.response_length);
print_buf(dns_msg.msg + dns_msg.response_position,
dns_msg.response_length);
printf("CNAME: ");
printf("Response: CNAME NO IP address");
printf("\nCNAME: ");
dns_print_readable_msg_label(dns_msg.response_position,
dns_msg.msg,
dns_msg.msg_size);
printf("\n");
ptr = dns_msg.response_position;
break;
@ -179,9 +188,7 @@ int dns_response(struct app_buf_t *_buf, int *response_type, int src_id)
}
dns_msg.answer_offset = dns_msg.answer_offset + 12
+ dns_msg.response_length;
+ dns_msg.response_length;
++i;
}