net: add dns support
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
This commit is contained in:
parent
232b46996c
commit
cd81aa6e3b
|
@ -274,6 +274,17 @@ int setenv_ip(const char *name, IPaddr_t ip);
|
|||
int string_to_ethaddr(const char *str, char *enetaddr);
|
||||
void ethaddr_to_string(const unsigned char *enetaddr, char *str);
|
||||
|
||||
#ifdef CONFIG_NET_RESOLV
|
||||
IPaddr_t resolv(char *host);
|
||||
#else
|
||||
static inline IPaddr_t resolv(char *host)
|
||||
{
|
||||
IPaddr_t ip = 0;
|
||||
string_to_ip(host, &ip);
|
||||
return ip;
|
||||
}
|
||||
#endif
|
||||
|
||||
/**
|
||||
* is_zero_ether_addr - Determine if give Ethernet address is all zeros.
|
||||
* @addr: Pointer to a six-byte array containing the Ethernet address
|
||||
|
|
|
@ -25,4 +25,8 @@ config NET_NETCONSOLE
|
|||
help
|
||||
This option adds support for a simple udp based network console.
|
||||
|
||||
config NET_RESOLV
|
||||
bool
|
||||
prompt "dns support"
|
||||
|
||||
endif
|
||||
|
|
|
@ -4,4 +4,5 @@ obj-$(CONFIG_NET) += net.o
|
|||
obj-$(CONFIG_NET_NFS) += nfs.o
|
||||
obj-$(CONFIG_NET_TFTP) += tftp.o
|
||||
obj-$(CONFIG_NET_PING) += ping.o
|
||||
obj-$(CONFIG_NET_RESOLV)+= dns.o
|
||||
obj-$(CONFIG_NET_NETCONSOLE) += netconsole.o
|
||||
|
|
|
@ -0,0 +1,264 @@
|
|||
/*
|
||||
* DNS support driver
|
||||
*
|
||||
* Copyright (c) 2008 Pieter Voorthuijsen <pieter.voorthuijsen@prodrive.nl>
|
||||
* Copyright (c) 2009 Robin Getz <rgetz@blackfin.uclinux.org>
|
||||
*
|
||||
* This is a simple DNS implementation for U-Boot. It will use the first IP
|
||||
* in the DNS response as NetServerIP. This can then be used for any other
|
||||
* network related activities.
|
||||
*
|
||||
* The packet handling is partly based on TADNS, original copyrights
|
||||
* follow below.
|
||||
*
|
||||
*/
|
||||
|
||||
/*
|
||||
* Copyright (c) 2004-2005 Sergey Lyubka <valenok@gmail.com>
|
||||
*
|
||||
* "THE BEER-WARE LICENSE" (Revision 42):
|
||||
* Sergey Lyubka 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.
|
||||
*/
|
||||
//#define DEBUG
|
||||
#include <common.h>
|
||||
#include <command.h>
|
||||
#include <net.h>
|
||||
#include <clock.h>
|
||||
#include <environment.h>
|
||||
#include <linux/err.h>
|
||||
|
||||
#define DNS_PORT 53
|
||||
|
||||
/* http://en.wikipedia.org/wiki/List_of_DNS_record_types */
|
||||
enum dns_query_type {
|
||||
DNS_A_RECORD = 0x01,
|
||||
DNS_CNAME_RECORD = 0x05,
|
||||
DNS_MX_RECORD = 0x0f,
|
||||
};
|
||||
|
||||
/*
|
||||
* DNS network packet
|
||||
*/
|
||||
struct header {
|
||||
uint16_t tid; /* Transaction ID */
|
||||
uint16_t flags; /* Flags */
|
||||
uint16_t nqueries; /* Questions */
|
||||
uint16_t nanswers; /* Answers */
|
||||
uint16_t nauth; /* Authority PRs */
|
||||
uint16_t nother; /* Other PRs */
|
||||
unsigned char data[1]; /* Data, variable length */
|
||||
};
|
||||
|
||||
#define STATE_INIT 0
|
||||
#define STATE_DONE 1
|
||||
|
||||
static struct net_connection *dns_con;
|
||||
static uint64_t dns_timer_start;
|
||||
static int dns_state;
|
||||
static IPaddr_t dns_ip;
|
||||
|
||||
static int dns_send(char *name)
|
||||
{
|
||||
int ret;
|
||||
struct header *header;
|
||||
enum dns_query_type qtype = DNS_A_RECORD;
|
||||
unsigned char *packet = net_udp_get_payload(dns_con);
|
||||
unsigned char *p, *s, *fullname, *dotptr;
|
||||
const unsigned char *domain;
|
||||
|
||||
/* Prepare DNS packet header */
|
||||
header = (struct header *)packet;
|
||||
header->tid = 1;
|
||||
header->flags = htons(0x100); /* standard query */
|
||||
header->nqueries = htons(1); /* Just one query */
|
||||
header->nanswers = 0;
|
||||
header->nauth = 0;
|
||||
header->nother = 0;
|
||||
|
||||
domain = getenv("domainname");
|
||||
|
||||
if (!strchr(name, '.') && domain && *domain)
|
||||
fullname = asprintf(".%s.%s.", name, domain);
|
||||
else
|
||||
fullname = asprintf(".%s.", name);
|
||||
|
||||
/* replace dots in fullname with chunk len */
|
||||
dotptr = fullname;
|
||||
do {
|
||||
int len;
|
||||
|
||||
s = strchr(dotptr + 1, '.');
|
||||
|
||||
len = s - dotptr - 1;
|
||||
|
||||
*dotptr = len;
|
||||
dotptr = s;
|
||||
} while (*(dotptr + 1));
|
||||
*dotptr = 0;
|
||||
//memory_display(fullname, 0, strlen(fullname), 1);
|
||||
strcpy(header->data, fullname);
|
||||
|
||||
p = header->data + strlen(fullname);
|
||||
|
||||
*p++ = 0; /* Mark end of host name */
|
||||
*p++ = 0; /* Some servers require double null */
|
||||
*p++ = (unsigned char)qtype; /* Query Type */
|
||||
|
||||
*p++ = 0;
|
||||
*p++ = 1; /* Class: inet, 0x0001 */
|
||||
|
||||
ret = net_udp_send(dns_con, p - packet);
|
||||
|
||||
free(fullname);
|
||||
|
||||
return ret;
|
||||
}
|
||||
|
||||
static void dns_handler(char *packet, unsigned len)
|
||||
{
|
||||
struct header *header;
|
||||
unsigned char *p, *e, *s;
|
||||
u16 type;
|
||||
int found, stop, dlen;
|
||||
short tmp;
|
||||
|
||||
debug("%s\n", __func__);
|
||||
|
||||
/* We sent 1 query. We want to see more that 1 answer. */
|
||||
header = (struct header *)net_eth_to_udp_payload(packet);;
|
||||
if (ntohs(header->nqueries) != 1)
|
||||
return;
|
||||
|
||||
/* Received 0 answers */
|
||||
if (header->nanswers == 0) {
|
||||
dns_state = STATE_DONE;
|
||||
debug("DNS server returned no answers\n");
|
||||
return;
|
||||
}
|
||||
|
||||
/* Skip host name */
|
||||
s = &header->data[0];
|
||||
e = packet + len;
|
||||
for (p = s; p < e && *p != '\0'; p++)
|
||||
continue;
|
||||
|
||||
/* We sent query class 1, query type 1 */
|
||||
tmp = p[1] | (p[2] << 8);
|
||||
if (&p[5] > e || ntohs(tmp) != DNS_A_RECORD) {
|
||||
debug("DNS response was not A record\n");
|
||||
return;
|
||||
}
|
||||
|
||||
/* Go to the first answer section */
|
||||
p += 5;
|
||||
|
||||
/* Loop through the answers, we want A type answer */
|
||||
for (found = stop = 0; !stop && &p[12] < e; ) {
|
||||
|
||||
/* Skip possible name in CNAME answer */
|
||||
if (*p != 0xc0) {
|
||||
while (*p && &p[12] < e)
|
||||
p++;
|
||||
p--;
|
||||
}
|
||||
debug("Name (Offset in header): %d\n", p[1]);
|
||||
|
||||
tmp = p[2] | (p[3] << 8);
|
||||
type = ntohs(tmp);
|
||||
debug("type = %d\n", type);
|
||||
if (type == DNS_CNAME_RECORD) {
|
||||
/* CNAME answer. shift to the next section */
|
||||
debug("Found canonical name\n");
|
||||
tmp = p[10] | (p[11] << 8);
|
||||
dlen = ntohs(tmp);
|
||||
debug("dlen = %d\n", dlen);
|
||||
p += 12 + dlen;
|
||||
} else if (type == DNS_A_RECORD) {
|
||||
debug("Found A-record\n");
|
||||
found = stop = 1;
|
||||
} else {
|
||||
debug("Unknown type\n");
|
||||
stop = 1;
|
||||
}
|
||||
}
|
||||
|
||||
if (found && &p[12] < e) {
|
||||
|
||||
tmp = p[10] | (p[11] << 8);
|
||||
dlen = ntohs(tmp);
|
||||
p += 12;
|
||||
dns_ip = net_read_ip(p);
|
||||
dns_state = STATE_DONE;
|
||||
}
|
||||
}
|
||||
|
||||
IPaddr_t resolv(char *host)
|
||||
{
|
||||
IPaddr_t ip;
|
||||
|
||||
if (!string_to_ip(host, &ip))
|
||||
return ip;
|
||||
|
||||
dns_ip = 0;
|
||||
|
||||
dns_state = STATE_INIT;
|
||||
|
||||
ip = getenv_ip("nameserver");
|
||||
if (!ip)
|
||||
return 0;
|
||||
|
||||
debug("resolving host %s via nameserver %s\n", host, getenv("nameserver"));
|
||||
|
||||
dns_con = net_udp_new(ip, DNS_PORT, dns_handler);
|
||||
if (IS_ERR(dns_con))
|
||||
return PTR_ERR(dns_con);
|
||||
dns_timer_start = get_time_ns();
|
||||
dns_send(host);
|
||||
|
||||
while (dns_state != STATE_DONE) {
|
||||
if (ctrlc()) {
|
||||
break;
|
||||
}
|
||||
net_poll();
|
||||
if (is_timeout(dns_timer_start, SECOND)) {
|
||||
dns_timer_start = get_time_ns();
|
||||
printf("T ");
|
||||
dns_send(host);
|
||||
}
|
||||
}
|
||||
|
||||
net_unregister(dns_con);
|
||||
|
||||
return dns_ip;
|
||||
}
|
||||
|
||||
static int do_host(struct command *cmdtp, int argc, char *argv[])
|
||||
{
|
||||
IPaddr_t ip;
|
||||
|
||||
if (argc != 2)
|
||||
return COMMAND_ERROR_USAGE;
|
||||
|
||||
ip = resolv(argv[1]);
|
||||
if (!ip)
|
||||
printf("unknown host %s\n", argv[1]);
|
||||
else {
|
||||
printf("%s is at ", argv[1]);
|
||||
print_IPaddr(ip);
|
||||
printf("\n");
|
||||
}
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
static const __maybe_unused char cmd_host_help[] =
|
||||
"Usage: host <hostname>\n";
|
||||
|
||||
BAREBOX_CMD_START(host)
|
||||
.cmd = do_host,
|
||||
.usage = "resolve a hostname",
|
||||
BAREBOX_CMD_HELP(cmd_host_help)
|
||||
BAREBOX_CMD_END
|
||||
|
Loading…
Reference in New Issue