dns_sd: Pass params pointer to DNS-SD functions

This will be used later to carry context information to the DNS-SD functions. Signed-off-by: Paul Cercueil <[email protected]>
analogdevicesinc · May 20, 2021 · 6d85454 · 6d85454
1 parent 763b803
commit 6d85454
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Showing 6 changed files with 107 additions and 58 deletions.
diff --git a/dns_sd.c b/dns_sd.c
@@ -40,7 +40,8 @@ static void dnssd_free_discovery_data(struct dns_sd_discovery_data *d)
 }
 
 /* Some functions for handling common linked list operations */
-static void dnssd_remove_node(struct dns_sd_discovery_data **ddata, int n)
+static void dnssd_remove_node(const struct iio_context_params *params,
+			      struct dns_sd_discovery_data **ddata, int n)
 {
 	struct dns_sd_discovery_data *d, *ndata, *ldata, *tdata;
 	int i;
@@ -81,10 +82,10 @@ struct iio_scan_backend_context {
 	struct addrinfo *res;
 };
 
-static int dnssd_fill_context_info(struct iio_context_info *info,
-		char *hostname, char *addr_str, int port)
+static int dnssd_fill_context_info(const struct iio_context_params *params,
+				   struct iio_context_info *info,
+				   char *hostname, char *addr_str, int port)
 {
-	const struct iio_context_params *params = &default_params;
 	struct iio_context *ctx;
 	char uri[sizeof("ip:") + MAXHOSTNAMELEN + sizeof (":65535") + 1];
 	char description[255], *p;
@@ -168,7 +169,8 @@ void dnssd_context_scan_free(struct iio_scan_backend_context *ctx)
  * This is sort of silly, but we have seen non-iio devices advertised
  * and discovered on the network. Oh well....
  */
-void port_knock_discovery_data(struct dns_sd_discovery_data **ddata)
+void port_knock_discovery_data(const struct iio_context_params *params,
+			       struct dns_sd_discovery_data **ddata)
 {
 	struct dns_sd_discovery_data *d, *ndata;
 	int i, ret;
@@ -216,7 +218,7 @@ void port_knock_discovery_data(struct dns_sd_discovery_data **ddata)
 		if (found) {
 			i++;
 		} else {
-			dnssd_remove_node(&d, i);
+			dnssd_remove_node(params, &d, i);
 		}
 	}
 	iio_mutex_unlock(d->lock);
@@ -225,7 +227,8 @@ void port_knock_discovery_data(struct dns_sd_discovery_data **ddata)
 	return;
 }
 
-void remove_dup_discovery_data(struct dns_sd_discovery_data **ddata)
+void remove_dup_discovery_data(const struct iio_context_params *params,
+			       struct dns_sd_discovery_data **ddata)
 {
 	struct dns_sd_discovery_data *d, *ndata, *mdata;
 	int i, j;
@@ -245,7 +248,7 @@ void remove_dup_discovery_data(struct dns_sd_discovery_data **ddata)
 					!strcmp(mdata->addr_str, ndata->addr_str)){
 				IIO_DEBUG("Removing duplicate in list: '%s'\n",
 						ndata->hostname);
-				dnssd_remove_node(&d, j);
+				dnssd_remove_node(params, &d, j);
 			}
 			j++;
 		}
@@ -259,11 +262,12 @@ void remove_dup_discovery_data(struct dns_sd_discovery_data **ddata)
 int dnssd_context_scan(struct iio_scan_backend_context *ctx,
 		struct iio_scan_result *scan_result)
 {
+	const struct iio_context_params *params = get_default_params();
 	struct iio_context_info **info;
 	struct dns_sd_discovery_data *ddata, *ndata;
 	int ret = 0;
 
-	ret = dnssd_find_hosts(&ddata);
+	ret = dnssd_find_hosts(params, &ddata);
 
 	/* if we return an error when no devices are found, then other scans will fail */
 	if (ret == -ENXIO) {
@@ -282,7 +286,7 @@ int dnssd_context_scan(struct iio_scan_backend_context *ctx,
 			break;
 		}
 
-		ret = dnssd_fill_context_info(*info,
+		ret = dnssd_fill_context_info(params, *info,
 				ndata->hostname, ndata->addr_str,ndata->port);
 		if (ret < 0) {
 			IIO_DEBUG("Failed to add %s (%s) err: %d\n", ndata->hostname, ndata->addr_str, ret);
@@ -291,16 +295,17 @@ int dnssd_context_scan(struct iio_scan_backend_context *ctx,
 	}
 
 fail:
-	dnssd_free_all_discovery_data(ddata);
+	dnssd_free_all_discovery_data(params, ddata);
 	return ret;
 }
 
-int dnssd_discover_host(char *addr_str, size_t addr_len, uint16_t *port)
+int dnssd_discover_host(const struct iio_context_params *params, char *addr_str,
+			size_t addr_len, uint16_t *port)
 {
 	struct dns_sd_discovery_data *ddata;
 	int ret = 0;
 
-	ret = dnssd_find_hosts(&ddata);
+	ret = dnssd_find_hosts(params, &ddata);
 
 	if (ret < 0)
 		goto host_fail;
@@ -311,14 +316,15 @@ int dnssd_discover_host(char *addr_str, size_t addr_len, uint16_t *port)
 	}
 
 host_fail:
-	dnssd_free_all_discovery_data(ddata);
+	dnssd_free_all_discovery_data(params, ddata);
 
 	/* negative error codes, 0 for no data */
 	return ret;
 }
 
-void dnssd_free_all_discovery_data(struct dns_sd_discovery_data *d)
+void dnssd_free_all_discovery_data(const struct iio_context_params *params,
+				   struct dns_sd_discovery_data *d)
 {
 	while (d)
-		dnssd_remove_node(&d, 0);
+		dnssd_remove_node(params, &d, 0);
 }
diff --git a/dns_sd.h b/dns_sd.h
@@ -35,6 +35,7 @@
 struct addrinfo;
 struct AvahiSimplePoll;
 struct AvahiAddress;
+struct iio_context_params;
 
 /* Common structure which all dns_sd_[*] files fill out
  * Anything that is dynamically allocated (malloc) needs to be managed
@@ -50,6 +51,10 @@ struct dns_sd_discovery_data {
 	struct dns_sd_discovery_data *next;
 };
 
+struct dns_sd_cb_data {
+	struct dns_sd_discovery_data *d;
+	const struct iio_context_params *params;
+};
 
 /* This functions is implemented in network.c, but used in dns_sd.c
  */
@@ -60,25 +65,31 @@ int create_socket(const struct addrinfo *addrinfo);
  */
 
 /* Resolves all IIO hosts on the available networks, and passes back a linked list */
-int dnssd_find_hosts(struct dns_sd_discovery_data ** ddata);
+int dnssd_find_hosts(const struct iio_context_params *params,
+		     struct dns_sd_discovery_data **ddata);
 
 /* Deallocates complete list of discovery data */
-void dnssd_free_all_discovery_data(struct dns_sd_discovery_data *d);
+void dnssd_free_all_discovery_data(const struct iio_context_params *params,
+				   struct dns_sd_discovery_data *d);
 
 /* These functions are common, and found in dns_sd.c, but are used in the
  * dns_sd_[*].c implementations or network.c
  */
 
 /* Passed back the first (random) IIOD service resolved by DNS DS. */
-int dnssd_discover_host(char *addr_str, size_t addr_len, uint16_t *port);
+int dnssd_discover_host(const struct iio_context_params *params,
+			char *addr_str, size_t addr_len, uint16_t *port);
 
 /* remove duplicates from the list */
-void remove_dup_discovery_data(struct dns_sd_discovery_data **ddata);
+void remove_dup_discovery_data(const struct iio_context_params *params,
+			       struct dns_sd_discovery_data **ddata);
 
 /* port knocks  */
-void port_knock_discovery_data(struct dns_sd_discovery_data **ddata);
+void port_knock_discovery_data(const struct iio_context_params *params,
+			       struct dns_sd_discovery_data **ddata);
 
 /* Use dnssd to resolve a given hostname */
-int dnssd_resolve_host(const char *hostname, char *ip_addr, const int addr_len);
+int dnssd_resolve_host(const struct iio_context_params *params,
+		       const char *hostname, char *ip_addr, const int addr_len);
 
 #endif /* __IIO_DNS_SD_H */
diff --git a/dns_sd_avahi.c b/dns_sd_avahi.c
@@ -50,11 +50,13 @@ static struct dns_sd_discovery_data *new_discovery_data(void)
 	return d;
 }
 
-static void avahi_process_resolved(struct dns_sd_discovery_data *ddata,
+static void avahi_process_resolved(struct dns_sd_cb_data *adata,
 				   const AvahiAddress *addr,
 				   const char *host_name,
 				   const uint16_t port)
 {
+	struct dns_sd_discovery_data *ddata = adata->d;
+
 	/* Avahi is multi-threaded, so lock the list */
 	iio_mutex_lock(ddata->lock);
 	ddata->resolved++;
@@ -106,7 +108,7 @@ static void __avahi_resolver_cb(AvahiServiceResolver *resolver,
 				AvahiLookupResultFlags flags,
 				void *d)
 {
-	struct dns_sd_discovery_data *ddata = d;
+	struct dns_sd_cb_data *adata = d;
 	AvahiClient *client;
 	int err;
 
@@ -126,7 +128,7 @@ static void __avahi_resolver_cb(AvahiServiceResolver *resolver,
 			  avahi_strerror(err));
 		break;
 	case AVAHI_RESOLVER_FOUND: {
-		avahi_process_resolved(ddata, address, host_name, port);
+		avahi_process_resolved(adata, address, host_name, port);
 		IIO_DEBUG("Avahi Resolver : service '%s' of type '%s' in domain '%s':\n",
 			  name, type, domain);
 		break;
@@ -144,7 +146,8 @@ static void avahi_host_resolver(AvahiHostNameResolver *resolver,
 				AvahiLookupResultFlags flags,
 				void *d)
 {
-	struct dns_sd_discovery_data *ddata = d;
+	struct dns_sd_cb_data *adata = d;
+	struct dns_sd_discovery_data *ddata = adata->d;
 	AvahiClient *client;
 	int err;
 
@@ -157,7 +160,7 @@ static void avahi_host_resolver(AvahiHostNameResolver *resolver,
 			  host_name, avahi_strerror(err));
 		break;
 	case AVAHI_RESOLVER_FOUND:
-		avahi_process_resolved(ddata, address, host_name, IIOD_PORT);
+		avahi_process_resolved(adata, address, host_name, IIOD_PORT);
 		break;
 	}
 
@@ -175,7 +178,8 @@ static void __avahi_browser_cb(AvahiServiceBrowser *browser,
 			       AvahiLookupResultFlags flags,
 			       void *d)
 {
-	struct dns_sd_discovery_data *ddata = (struct dns_sd_discovery_data *) d;
+	struct dns_sd_cb_data *adata = d;
+	struct dns_sd_discovery_data *ddata = adata->d;
 	struct AvahiClient *client = avahi_service_browser_get_client(browser);
 	unsigned int i;
 	struct timespec ts;
@@ -199,7 +203,7 @@ static void __avahi_browser_cb(AvahiServiceBrowser *browser,
 		if(!avahi_service_resolver_new(client, iface,
 					       proto, name, type, domain,
 					       AVAHI_PROTO_UNSPEC, 0,
-					       __avahi_resolver_cb, d)) {
+					       __avahi_resolver_cb, adata)) {
 			IIO_ERROR("Failed to resolve service '%s\n", name);
 		} else {
 			iio_mutex_lock(ddata->lock);
@@ -233,9 +237,11 @@ static void __avahi_browser_cb(AvahiServiceBrowser *browser,
  * The returned value is zero on success, negative error code on failure.
  */
 
-int dnssd_find_hosts(struct dns_sd_discovery_data **ddata)
+int dnssd_find_hosts(const struct iio_context_params *params,
+		     struct dns_sd_discovery_data **ddata)
 {
 	struct dns_sd_discovery_data *d;
+	struct dns_sd_cb_data adata;
 	AvahiClient *client;
 	AvahiServiceBrowser *browser;
 	int ret = 0;
@@ -244,16 +250,19 @@ int dnssd_find_hosts(struct dns_sd_discovery_data **ddata)
 	if (!d)
 		return -ENOMEM;
 
+	adata.params = params;
+	adata.d = d;
+
 	d->lock = iio_mutex_create();
 	if (!d->lock) {
-		dnssd_free_all_discovery_data(d);
+		dnssd_free_all_discovery_data(params, d);
 		return -ENOMEM;
 	}
 
 	d->poll = avahi_simple_poll_new();
 	if (!d->poll) {
 		iio_mutex_destroy(d->lock);
-		dnssd_free_all_discovery_data(d);
+		dnssd_free_all_discovery_data(params, d);
 		return -ENOMEM;
 	}
 
@@ -268,7 +277,7 @@ int dnssd_find_hosts(struct dns_sd_discovery_data **ddata)
 	browser = avahi_service_browser_new(client,
 					    AVAHI_IF_UNSPEC, AVAHI_PROTO_UNSPEC,
 					    "_iio._tcp", NULL, 0,
-					    __avahi_browser_cb, d);
+					    __avahi_browser_cb, &adata);
 	if (!browser) {
 		ret = avahi_client_errno(client);
 		IIO_ERROR("Unable to create Avahi DNS-SD browser: %s\n",
@@ -280,8 +289,8 @@ int dnssd_find_hosts(struct dns_sd_discovery_data **ddata)
 	avahi_simple_poll_loop(d->poll);
 
 	if (d->resolved) {
-		port_knock_discovery_data(&d);
-		remove_dup_discovery_data(&d);
+		port_knock_discovery_data(params, &d);
+		remove_dup_discovery_data(params, &d);
 	} else
 		ret = -ENXIO;
 
@@ -296,10 +305,11 @@ int dnssd_find_hosts(struct dns_sd_discovery_data **ddata)
 	return ret;
 }
 
-static void avahi_resolve_host(struct dns_sd_discovery_data *d,
+static void avahi_resolve_host(struct dns_sd_cb_data *adata,
 			       const char *hostname,
 			       const AvahiProtocol proto)
 {
+	struct dns_sd_discovery_data *d = adata->d;
 	AvahiClient *client;
 	AvahiHostNameResolver *resolver;
 	int ret;
@@ -315,8 +325,9 @@ static void avahi_resolve_host(struct dns_sd_discovery_data *d,
 		goto err_free_poll;
 	}
 
-	resolver = avahi_host_name_resolver_new(client, AVAHI_IF_UNSPEC, proto, hostname, proto, 0,
-						avahi_host_resolver, d);
+	resolver = avahi_host_name_resolver_new(client, AVAHI_IF_UNSPEC, proto,
+						hostname, proto, 0,
+						avahi_host_resolver, adata);
 	if (!resolver) {
 		ret = avahi_client_errno(client);
 		IIO_ERROR("Unable to create Avahi DNS-SD browser: %s\n",
@@ -333,11 +344,13 @@ static void avahi_resolve_host(struct dns_sd_discovery_data *d,
 	avahi_simple_poll_free(d->poll);
 }
 
-int dnssd_resolve_host(const char *hostname,
+int dnssd_resolve_host(const struct iio_context_params *params,
+		       const char *hostname,
 		       char *ip_addr,
 		       const int addr_len)
 {
 	struct dns_sd_discovery_data *d;
+	struct dns_sd_cb_data adata;
 	int ret = 0;
 
 	if (!hostname || hostname[0] == '\0')
@@ -352,21 +365,25 @@ int dnssd_resolve_host(const char *hostname,
 		ret = -ENOMEM;
 		goto err_free_data;
 	}
+
+	adata.params = params;
+	adata.d = d;
+
 	/*
 	 * The reason not to use AVAHI_PROTO_UNSPEC is that avahi sometimes resolves the host
 	 * to an ipv6 link local address which is not suitable to be used by connect. In fact,
 	 * `port_knock_discovery_data()` would discard this entry. On the other hand, some users
 	 * might really want to use ipv6 and have their environment correctly configured. Hence,
 	 * we try to resolve both in ipv4 and ipv6...
 	 */
-	avahi_resolve_host(d, hostname, AVAHI_PROTO_INET);
+	avahi_resolve_host(&adata, hostname, AVAHI_PROTO_INET);
 #ifdef HAVE_IPV6
-	avahi_resolve_host(d, hostname, AVAHI_PROTO_INET6);
+	avahi_resolve_host(&adata, hostname, AVAHI_PROTO_INET6);
 #endif
 
 	if (d->resolved) {
-		port_knock_discovery_data(&d);
-		remove_dup_discovery_data(&d);
+		port_knock_discovery_data(params, &d);
+		remove_dup_discovery_data(params, &d);
 	} else {
 		ret = -ENXIO;
 		goto err_mutex_destroy;
@@ -383,6 +400,6 @@ int dnssd_resolve_host(const char *hostname,
 err_mutex_destroy:
 	iio_mutex_destroy(d->lock);
 err_free_data:
-	dnssd_free_all_discovery_data(d);
+	dnssd_free_all_discovery_data(params, d);
 	return ret;
 }