(a12) allow clients to push appl update

This allows clients with the correct permission groups (default is deny)
to update and (soon) add new appls to the directory index. These are
currently not persisted, and there's some reason to not permit that
before the feature is more reliable and as an option.

It also wires up SIGUSR1 on the directory server process to force a
rescan/rebuild of the index (discarding any user-provided updates).

The intent for that is to have an accepted set of shared appls, allow
devs to test out new ones before committing to it. That commit can come
as a sideband git push into a trigger that sends the SIGUSR1. The
fancier option would be to move this into a database store of its own,
but walk before flying and all that.

With the appl- push also comes the scaffolding for having server side
appl shared resources, with two levels of updates. One with the style of
a traditional 'form upload' - while the other a more privileged
corresponding to appltemp file creation.

In the same vein, things are now mostly prepped for attaching a
'controller' to a hosted appl, meaning server side scripts to act as a
message router / server side logic for networked appls.

The last big hurdle in this is to rework how the client side launches
arcan-lwa, and specifically the monitoring interface. Currently that is
just a block FILE* hack with some plaintext strings, but we kindof need
background processing to support hot reloading, and with that there's no
point to not go full shmifsrv and gain the advantages of having the
control / monitor channel also speak shmif in lwa.

src/a12/a12.c

@@ -18,6 +18,7 @@
 
 #include "a12.h"
 #include "a12_int.h"
+#include "net/a12_helper.h"
 
 #include "a12_decode.h"
 #include "a12_encode.h"
@@ -840,6 +841,7 @@ static void command_binarystream(struct a12_state* S)
 	unpack_u32(&bframe->identifier, &S->decode[31]);
 	memcpy(bframe->checksum, &S->decode[35], 16);
 	bframe->tmp_fd = -1;
+	memcpy(bframe->extid, &S->decode[53], 16);
 
 	bframe->active = true;
 	a12int_trace(A12_TRACE_BTRANSFER,
@@ -866,6 +868,7 @@ static void command_binarystream(struct a12_state* S)
 		.dcont = S->channels[channel].cont,
 		.fd = -1
 	};
+	memcpy(bm.extid, bframe->extid, 16);
 	memcpy(bm.checksum, bframe->checksum, 16);
 
 	if (S->binary_handler){
@@ -1311,8 +1314,8 @@ void a12_set_session(
  * Simplified form of enqueue bstream below, we already have the buffer
  * in memory so just build a different blob-out node with a copy
  */
-void a12_enqueue_blob(
-	struct a12_state* S, const char* const buf, size_t buf_sz, uint32_t id)
+void a12_enqueue_blob(struct a12_state* S, const char* const buf,
+	size_t buf_sz, uint32_t id, int type, const char extid[static 16])
 {
 	struct blob_out** next = alloc_attach_blob(S);
 	if (!next)
@@ -1331,7 +1334,8 @@ void a12_enqueue_blob(
 	(*next)->buf_sz = buf_sz;
 	(*next)->left = buf_sz;
 	(*next)->identifier = id;
-	(*next)->type = A12_BTYPE_BLOB;
+	(*next)->type = type;
+	memcpy((*next)->extid, extid, 16);
 
 	blake3_hasher hash;
 	blake3_hasher_init(&hash);
@@ -1363,7 +1367,8 @@ void a12_enqueue_blob(
  *
  */
 void a12_enqueue_bstream(struct a12_state* S,
-	int fd, int type, uint32_t id, bool streaming, size_t sz)
+	int fd, int type, uint32_t id, bool streaming, size_t sz,
+	const char extid[static 16])
 {
 	struct blob_out** parent = alloc_attach_blob(S);
 	if (!parent)
@@ -1373,6 +1378,10 @@ void a12_enqueue_bstream(struct a12_state* S,
 	next->type = type;
 	next->identifier = id;
 
+	if (extid && (type == A12_BTYPE_APPL || type == A12_BTYPE_APPL_RESOURCE)){
+		snprintf(next->extid, 16, "%s", extid);
+	}
+
 	if (type == A12_BTYPE_FONT_SUPPL || type == A12_BTYPE_FONT)
 		next->rampup_seqnr = S->current_seqnr + 1;
 
@@ -1773,23 +1782,36 @@ static void command_pingpacket(struct a12_state* S, uint32_t sid)
 		S->congestion_stats.frame_window[i] = 0;
 }
 
+static void dirstate_item(struct a12_state* S, struct appl_meta* C)
+{
+	uint8_t outb[CONTROL_PACKET_SIZE];
+	build_control_header(S, outb, COMMAND_DIRSTATE);
+
+	if (C->role == ROLE_SOURCE || C->role == ROLE_DIR){
+		a12int_notify_dynamic_resource(
+			S, C->dynamic.petname, C->dynamic.key, C->role, true);
+		return;
+	}
+
+	pack_u16(C->identifier, &outb[18]);
+	pack_u16(C->categories, &outb[20]);
+	pack_u16(C->permissions, &outb[22]);
+	memcpy(&outb[24], C->hash, 4);
+	pack_u64(C->buf_sz, &outb[28]);
+	memcpy(&outb[36], C->appl.name, 18);
+	memcpy(&outb[55], C->appl.short_descr, 69);
+	a12int_append_out(S,
+		STATE_CONTROL_PACKET, outb, CONTROL_PACKET_SIZE, NULL, 0);
+	a12int_trace(A12_TRACE_DIRECTORY, "send:name=%s", C->appl.name);
+}
+
 static void send_dirlist(struct a12_state* S)
 {
 	uint8_t outb[CONTROL_PACKET_SIZE];
 	struct appl_meta* C = S->directory;
 
 	while (C){
-		build_control_header(S, outb, COMMAND_DIRSTATE);
-		pack_u16(C->identifier, &outb[18]);
-		pack_u16(C->categories, &outb[20]);
-		pack_u16(C->permissions, &outb[22]);
-		memcpy(&outb[24], C->hash, 4);
-		pack_u64(C->buf_sz, &outb[28]);
-		memcpy(&outb[36], C->applname, 18);
-		memcpy(&outb[55], C->short_descr, 69);
-		a12int_append_out(S,
-			STATE_CONTROL_PACKET, outb, CONTROL_PACKET_SIZE, NULL, 0);
-		a12int_trace(A12_TRACE_DIRECTORY, "send:name=%s", C->applname);
+		dirstate_item(S, C);
 		C = C->next;
 	}
 
@@ -1800,6 +1822,43 @@ static void send_dirlist(struct a12_state* S)
 		STATE_CONTROL_PACKET, outb, CONTROL_PACKET_SIZE, NULL, 0);
 }
 
+/* just unpack and forward to the event handler, arcan proper can deal with the
+ * event as it is mostly verbatim when it passes through afsrv_net and
+ * arcan-net has the same structures available */
+static void command_dirdiscover(struct a12_state* S, void (*on_event)
+	(struct arcan_shmif_cont*, int chid, struct arcan_event*, void*), void* tag)
+{
+	uint8_t type = S->decode[18];
+	bool added = S->decode[19];
+
+/* block separator */
+	char petname[17] = {0};
+	memcpy(petname, &S->decode[20], 16);
+	for (size_t i = 0; petname[i]; i++)
+		if (petname[i] == ':')
+			petname[i] = '_';
+
+/* netstate event type model match that of a12 dirdiscover command */
+	struct arcan_event ev = {
+		.category = EVENT_EXTERNAL,
+		.ext.kind = EVENT_EXTERNAL_NETSTATE,
+		.ext.netstate = {
+			.space = 5,
+			.state = added ? 1 : 0,
+			.type = type
+		}
+	};
+
+/* pack kpub as base64 (43 bytes) */
+	size_t outl;
+	unsigned char* pk =
+		a12helper_tob64(&S->decode[36], 32, &outl);
+	snprintf((char*)&ev.ext.netstate.name, 66, "%d:%s", petname, pk);
+	free(pk);
+
+	on_event(S->channels[0].cont, 0, &ev, tag);
+}
+
 static void add_dirent(struct a12_state* S)
 {
 /* end of update is marked with an empty entry */
@@ -1821,8 +1880,8 @@ static void add_dirent(struct a12_state* S)
 	unpack_u16(&new->permissions, &S->decode[22]);
 	memcpy(new->hash, &S->decode[24], 4);
 	unpack_u64(&new->buf_sz, &S->decode[28]);
-	memcpy(new->applname, &S->decode[36], 18);
-	memcpy(new->short_descr, &S->decode[55], 69);
+	memcpy(new->appl.name, &S->decode[36], 18);
+	memcpy(new->appl.short_descr, &S->decode[55], 69);
 	new->update_ts = arcan_timemillis();
 
 	if (!S->directory){
@@ -1926,8 +1985,12 @@ static void process_control(struct a12_state* S, void (*on_event)
  * 3. if this is not a rekey response package, send the new pubk in response */
 	break;
 	case COMMAND_DIRLIST:
+		S->notify_dynamic = S->decode[18];
 		send_dirlist(S);
 	break;
+	case COMMAND_DIRDISCOVER:
+		command_dirdiscover(S, on_event, tag);
+	break;
 
 /* Security notice: this allows the remote end to update / populate the
  * local directory list for the ongoing session. If we are operating in
@@ -2725,6 +2788,9 @@ static size_t begin_bstream(struct a12_state* S, struct blob_out* node)
 		ZSTD_CCtx_setParameter(node->zstd, ZSTD_c_nbWorkers, 4);
 		outb[52] = 1;
 	}
+
+/* only used for two subtypes but will be set to 0 otherwise */
+	memcpy(&outb[53], node->extid, 16);
 	a12int_append_out(S, STATE_CONTROL_PACKET, outb, CONTROL_PACKET_SIZE, NULL, 0);
 
 	node->active = true;
@@ -3050,14 +3116,14 @@ a12_channel_enqueue(struct a12_state* S, struct arcan_event* ev)
  * the rest */
 		case TARGET_COMMAND_RESTORE:
 			a12_enqueue_bstream(S,
-				ev->tgt.ioevs[0].iv, A12_BTYPE_STATE, false, 0, 0);
+				ev->tgt.ioevs[0].iv, A12_BTYPE_STATE, false, 0, 0, NULL);
 			return true;
 		break;
 
 /* let the bstream- side determine if the source is streaming or not */
 		case TARGET_COMMAND_BCHUNK_IN:
 			a12_enqueue_bstream(S,
-				ev->tgt.ioevs[0].iv, A12_BTYPE_BLOB, false, 0, 0);
+				ev->tgt.ioevs[0].iv, A12_BTYPE_BLOB, false, 0, 0, NULL);
 				return true;
 		break;
 
@@ -3067,7 +3133,7 @@ a12_channel_enqueue(struct a12_state* S, struct arcan_event* ev)
 		case TARGET_COMMAND_FONTHINT:
 			a12_enqueue_bstream(S,
 				ev->tgt.ioevs[0].iv, ev->tgt.ioevs[4].iv == 1 ?
-				A12_BTYPE_FONT_SUPPL : A12_BTYPE_FONT, false, 0, 0
+				A12_BTYPE_FONT_SUPPL : A12_BTYPE_FONT, false, 0, 0, NULL
 			);
 		break;
 		default:
@@ -3187,3 +3253,24 @@ int a12_remote_mode(struct a12_state* S)
 {
 	return S->remote_mode;
 }
+
+void a12int_notify_dynamic_resource(struct a12_state* S,
+		const char* petname, uint8_t kpub[static 32], uint8_t role, bool added)
+{
+	if (!S->notify_dynamic)
+		return;
+
+	a12int_trace(A12_TRACE_DIRECTORY,
+		"dynamic:forward:name=%s:role=%d:added=%d", petname,(int)role,(int)added);
+
+	uint8_t outb[CONTROL_PACKET_SIZE];
+	build_control_header(S, outb, COMMAND_DIRDISCOVER);
+	outb[18] = role;
+	outb[19] = added;
+/* note: this does not align on unicode codepoints or utf8- encoding,
+ * petname is expected to have been shortened / aligned before */
+	snprintf((char*)&outb[20], 16, "%s", petname);
+	memcpy(&outb[36], kpub, 32);
+	a12int_append_out(S,
+		STATE_CONTROL_PACKET, outb, CONTROL_PACKET_SIZE, NULL, 0);
+}

src/a12/a12.h

@@ -264,15 +264,23 @@ enum a12_bstream_type {
 	A12_BTYPE_FONT = 1,
 	A12_BTYPE_FONT_SUPPL = 2,
 	A12_BTYPE_BLOB = 3,
-	A12_BTYPE_CRASHDUMP = 4
+
+/* directory mode only */
+	A12_BTYPE_CRASHDUMP = 4,
+	A12_BTYPE_APPL = 5,
+	A12_BTYPE_APPL_RESOURCE = 6,
+	A12_BTYPE_APPL_CONTROLLER = 7
 };
+
 void
 a12_enqueue_bstream(struct a12_state*,
-	int fd, int type, uint32_t id, bool streaming, size_t sz);
+	int fd, int type, uint32_t id, bool streaming,
+	size_t sz, const char extid[static 16]);
 
 void
 a12_enqueue_blob(
-	struct a12_state*, const char* const, size_t, uint32_t id);
+	struct a12_state*, const char* const, size_t, uint32_t id,
+	int type, const char extid[static 16]);
 
 /*
  * Get a status code indicating the state of the connection.
@@ -463,6 +471,7 @@ struct a12_bhandler_meta {
 	uint8_t channel;
 	uint64_t streamid;
 	uint32_t identifier;
+	char extid[17];
 	int fd;
 	struct arcan_shmif_cont* dcont;
 };

src/a12/a12_int.h

@@ -75,6 +75,8 @@ enum control_commands {
 	COMMAND_REKEY        = 8, /* new x25519 change               */
 	COMMAND_DIRLIST      = 9, /* request list of items           */
 	COMMAND_DIRSTATE     = 10,/* update / present a new appl     */
+	COMMAND_DIRDISCOVER  = 11,/* dynamic source/dir entry        */
+	COMMAND_DIROPEN      = 12,/* mediate access to a dyn src/dir */
 };
 
 enum hello_mode {
@@ -138,6 +140,7 @@ struct binary_frame {
 	uint32_t identifier;
 	uint8_t checksum[16];
 	int64_t streamid; /* actual type is uint32 but -1 for cancel */
+	char extid[16];
 	struct ZSTD_DCtx_s* zstd;
 };
 
@@ -186,6 +189,7 @@ struct blob_out {
 	uint8_t chid;
 	int type;
 	uint32_t identifier;
+	char extid[16];
 	size_t left;
 	char* buf;
 	size_t buf_sz;
@@ -236,6 +240,7 @@ struct a12_state {
 	struct a12_context_options* opts;
 	struct appl_meta* directory;
 	uint64_t directory_clk;
+	bool notify_dynamic;
 
 	uint8_t last_mac_in[MAC_BLOCK_SZ];
 
@@ -353,23 +358,48 @@ struct appl_meta {
 	uint16_t permissions;
 	uint8_t hash[4];
 
-	char applname[18];
-	char short_descr[69];
-
 	int role;
+	union {
+		struct {
+			char name[18];
+			char short_descr[69];
+		} appl;
+
+		struct {
+			char petname[16];
+			uint8_t key[32];
+		} dynamic;
+	};
+
 	uint64_t update_ts;
 };
 
 /* takes ownership of appl_meta */
 void a12int_set_directory(struct a12_state*, struct appl_meta*);
 
+/*
+ * For a state in directory server mode,
+ * and with the other end having requested notifications as part of a
+ * previous dirlist request.
+ */
+void
+	a12int_notify_dynamic_resource(
+		struct a12_state*,
+		const char* petname,
+		uint8_t kpub[static 32],
+		uint8_t role, bool added);
+
 /* get the current directory -
  * this is only valid between a12* calls on the state.
  * The clock is an atomic counter that increments each time the directory
  * is updated. */
 struct appl_meta* a12int_get_directory(struct a12_state*, uint64_t* clk);
 
-/* send the command to get a directory listing,
- * results will be provided as BCHUNKHINT events */
-void a12int_request_dirlist(struct a12_state*, bool);
+/* Send the command to get a directory listing,
+ * results will be provided as BCHUNKHINT events for appls and NETSTATE
+ * ones for entries tied to dynamic sources / directories.
+ *
+ * If notify is set changes will be sent dynamically */
+void a12int_request_dirlist(struct a12_state*, bool notify);
+
 #endif