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#include <stdlib.h>
#include <unistd.h>
#include <osmocom/mslookup/mslookup.h>
#include <osmocom/mslookup/mdns.h>
#include "logging.h"
#include "mslookup_server.h"
#include "mslookup_server_mdns.h"
static void osmo_mslookup_server_mdns_tx(struct osmo_mslookup_server_mdns *server,
const struct osmo_mdns_request *req,
const struct osmo_mslookup_query *query,
const struct osmo_mslookup_result *result)
{
const char *errmsg = NULL;
struct msgb *msg;
struct osmo_mdns_answer ans;
struct osmo_mdns_record *rec_age;
struct osmo_mdns_record rec_ip_v4 = {};
struct osmo_mdns_record *rec_ip_v4_port;
struct osmo_mdns_record rec_ip_v6 = {};
struct osmo_mdns_record *rec_ip_v6_port;
uint32_t ip_v4;
struct in6_addr ip_v6;
void *ctx = talloc_named_const(server, 0, __func__);
LOGP(DDGSM, LOGL_DEBUG, "%s: sending mDNS response\n",
osmo_mslookup_result_name_c(OTC_SELECT, query, result));
osmo_mdns_answer_init(&ans);
ans.id = req->id;
ans.domain = req->domain;
rec_age = dns_encode_txt_record(ctx, "age", "%u", result->age);
llist_add(&rec_age->list, &ans.records);
if (osmo_sockaddr_str_is_nonzero(&result->host_v4)) {
if (osmo_sockaddr_str_to_32(&result->host_v4, &ip_v4)) {
errmsg = "Error encoding IPv4 address";
goto clean_and_exit;
}
rec_ip_v4.type = OSMO_MSLOOKUP_MDNS_RECORD_TYPE_A;
rec_ip_v4.data = (void*)&ip_v4;
rec_ip_v4.length = sizeof(ip_v4);
llist_add(&rec_ip_v4.list, &ans.records);
rec_ip_v4_port = dns_encode_txt_record(ctx, "port", "%u", result->host_v4.port);
if (!rec_ip_v4_port) {
errmsg = "Error encoding IPv4 port";
goto clean_and_exit;
}
llist_add(&rec_ip_v4_port->list, &ans.records);
}
if (osmo_sockaddr_str_is_nonzero(&result->host_v6)) {
if (osmo_sockaddr_str_to_in6_addr(&result->host_v6, &ip_v6)) {
errmsg = "Error encoding IPv6 address";
goto clean_and_exit;
}
rec_ip_v6.type = OSMO_MSLOOKUP_MDNS_RECORD_TYPE_AAAA;
rec_ip_v6.data = (void*)&ip_v6;
rec_ip_v6.length = sizeof(ip_v6);
llist_add(&rec_ip_v6.list, &ans.records);
rec_ip_v6_port = dns_encode_txt_record(ctx, "port", "%u", result->host_v6.port);
if (!rec_ip_v6_port) {
errmsg = "Error encoding IPv6 port";
goto clean_and_exit;
}
llist_add(&rec_ip_v6_port->list, &ans.records);
}
msg = msgb_alloc(1024, __func__);
if (dns_encode_answer(ctx, msg, &ans)) {
errmsg = "Error encoding DNS answer packet";
goto clean_and_exit;
}
if (osmo_mdns_sock_send(server->sock, msg))
errmsg = "Error sending DNS answer";
clean_and_exit:
if (errmsg)
LOGP(DDGSM, LOGL_ERROR, "%s: DNS: %s\n", osmo_mslookup_result_name_c(ctx, query, result), errmsg);
talloc_free(ctx);
}
static void osmo_mslookup_server_mdns_handle_request(struct osmo_mslookup_server_mdns *server,
const struct osmo_mdns_request *req)
{
struct osmo_mslookup_query query;
struct osmo_mslookup_result result;
if (osmo_mslookup_query_from_domain_str(&query, req->domain)) {
LOGP(DDGSM, LOGL_ERROR, "mDNS mslookup server: unable to parse request domain string: %s\n",
osmo_quote_str_c(OTC_SELECT, req->domain, -1));
return;
}
osmo_mslookup_server_rx(&query, &result);
/* Error logging already happens in osmo_mslookup_server_rx() */
if (result.rc != OSMO_MSLOOKUP_RC_OK)
return;
osmo_mslookup_server_mdns_tx(server, req, &query, &result);
}
static int osmo_mslookup_server_mdns_rx(struct osmo_fd *osmo_fd, unsigned int what)
{
struct osmo_mslookup_server_mdns *server = osmo_fd->data;
struct osmo_mdns_request *req;
int n;
uint8_t buffer[1024];
void *ctx;
/* Parse the message and print it */
n = read(osmo_fd->fd, buffer, sizeof(buffer));
if (n < 0)
return n;
ctx = talloc_named_const(server, 0, __func__);
req = dns_decode_request(ctx, buffer, n);
if (!req) {
LOGP(DDGSM, LOGL_DEBUG, "mDNS rx: ignoring: not a request\n");
talloc_free(ctx);
return -1;
}
LOGP(DDGSM, LOGL_DEBUG, "mDNS rx request: %s\n", osmo_quote_str_c(OTC_SELECT, req->domain, -1));
osmo_mslookup_server_mdns_handle_request(server, req);
talloc_free(ctx);
return n;
}
struct osmo_mslookup_server_mdns *osmo_mslookup_server_mdns_start(void *ctx, const struct osmo_sockaddr_str *bind_addr)
{
struct osmo_mslookup_server_mdns *server = talloc_zero(ctx, struct osmo_mslookup_server_mdns);
OSMO_ASSERT(server);
*server = (struct osmo_mslookup_server_mdns){
.bind_addr = *bind_addr,
};
server->sock = osmo_mdns_sock_init(server,
bind_addr->ip, bind_addr->port, true,
osmo_mslookup_server_mdns_rx,
server, 0);
if (!server->sock) {
LOGP(DDGSM, LOGL_ERROR,
"mslookup mDNS server: error initializing multicast bind on " OSMO_SOCKADDR_STR_FMT "\n",
OSMO_SOCKADDR_STR_FMT_ARGS(bind_addr));
talloc_free(server);
return NULL;
}
return server;
}
void osmo_mslookup_server_mdns_stop(struct osmo_mslookup_server_mdns *server)
{
if (!server)
return;
osmo_mdns_sock_cleanup(server->sock);
talloc_free(server);
}
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