stream_{cli,srv}: Add 'res' param to read_cb2

Notify user about read errors, similar to what is supported in the
earlier ofd cb backend of osmo_stream_cli/srv:
https://osmocom.org/issues/6405#note-15

Related: OS#6405
Fixes: 5fec34a9f2
Fixes: 0245cf5e07
Change-Id: I395c75ff1e9904757ce1d767a9ac2f779593c4c8

examples/ipa-stream-client.c

@@ -102,13 +102,19 @@ static int connect_cb(struct osmo_stream_cli *conn)
 	return 0;
 }
 
-static int read_cb(struct osmo_stream_cli *conn, struct msgb *msg)
+static int read_cb(struct osmo_stream_cli *conn, int res, struct msgb *msg)
 {
 	int num;
 	struct msg_sent *cur, *tmp, *found = NULL;
 
 	LOGP(DIPATEST, LOGL_DEBUG, "received message from stream (payload len=%d)\n", msgb_length(msg));
 
+	if (res <= 0) {
+		LOGP(DIPATEST, LOGL_ERROR, "Event with no data! %d\n", res);
+		msgb_free(msg);
+		return 0;
+	}
+
 	if (osmo_ipa_process_msg(msg) < 0) {
 		LOGP(DIPATEST, LOGL_ERROR, "bad IPA message\n");
 		msgb_free(msg);

examples/ipa-stream-server.c

@@ -47,8 +47,15 @@ void sighandler(int foo)
 	exit(EXIT_SUCCESS);
 }
 
-int read_cb(struct osmo_stream_srv *conn, struct msgb *msg)
+int read_cb(struct osmo_stream_srv *conn, int res, struct msgb *msg)
 {
+	if (res <= 0) {
+		LOGP(DSTREAMTEST, LOGL_ERROR, "cannot receive message (%d)\n", res);
+		msgb_free(msg);
+		osmo_stream_srv_destroy(conn);
+		return -EBADF;
+	}
+
 	LOGP(DSTREAMTEST, LOGL_DEBUG, "received message from stream (payload len=%d)\n", msgb_length(msg));
 
 	osmo_ipa_msg_push_headers(msg, osmo_ipa_msgb_cb_proto(msg), osmo_ipa_msgb_cb_proto_ext(msg));

examples/stream-client.c

@@ -54,10 +54,17 @@ static int disconnect_cb(struct osmo_stream_cli *conn)
 	return 0;
 }
 
-static int read_cb(struct osmo_stream_cli *conn, struct msgb *msg)
+static int read_cb(struct osmo_stream_cli *conn, int res, struct msgb *msg)
 {
 	LOGP(DSTREAMTEST, LOGL_NOTICE, "receiving message from stream... ");
 
+	if (res < 0) {
+		LOGPC(DSTREAMTEST, LOGL_ERROR, "cannot receive message (res = %d)\n", res);
+		msgb_free(msg);
+		return 0;
+	}
+
+
 	LOGPC(DSTREAMTEST, LOGL_NOTICE, "got %d bytes: %s\n", msg->len, msgb_hexdump(msg));
 
 	msgb_free(msg);

examples/stream-server.c

@@ -3,6 +3,7 @@
 #include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
+#include <errno.h>
 
 #include <osmocom/core/select.h>
 #include <osmocom/core/socket.h>
@@ -44,10 +45,20 @@ void sighandler(int foo)
 	signal(SIGINT, SIG_DFL);
 }
 
-int read_cb(struct osmo_stream_srv *conn, struct msgb *msg)
+int read_cb(struct osmo_stream_srv *conn, int res, struct msgb *msg)
 {
 	LOGP(DSTREAMTEST, LOGL_NOTICE, "receiving message from stream... ");
 
+	if (res <= 0) {
+		if (res < 0)
+			LOGPC(DSTREAMTEST, LOGL_ERROR, "cannot receive message: %s\n", strerror(-res));
+		else
+			LOGPC(DSTREAMTEST, LOGL_ERROR, "client closed connection\n");
+		msgb_free(msg);
+		osmo_stream_srv_destroy(conn);
+		return -EBADF;
+	}
+
 	LOGPC(DSTREAMTEST, LOGL_NOTICE, "got %d bytes: %s\n", msg->len, msgb_hexdump(msg));
 
 	msgb_free(msg);

include/osmocom/netif/stream.h

@@ -102,7 +102,14 @@ struct osmo_stream_srv;
 
 typedef int (*osmo_stream_srv_read_cb_t)(struct osmo_stream_srv *conn);
 typedef int (*osmo_stream_srv_closed_cb_t)(struct osmo_stream_srv *conn);
-typedef int (*osmo_stream_srv_read_cb2_t)(struct osmo_stream_srv *conn, struct msgb *msg);
+
+/*! Completion call-back function when something was read from from the stream client socket.
+ * \param[in] conn Stream Server that got receive event.
+ * \param[in] res return value of the read()/recvmsg()/... call, or -errno in case of error.
+ * \param[in] msg message buffer containing the read data. Ownership is transferred to the
+ * call-back, and it must make sure to msgb_free() it eventually! */
+typedef int (*osmo_stream_srv_read_cb2_t)(struct osmo_stream_srv *conn, int res, struct msgb *msg);
+
 typedef int (*osmo_stream_srv_segmentation_cb_t)(struct msgb *msg);
 
 struct osmo_stream_srv *osmo_stream_srv_create(void *ctx, struct osmo_stream_srv_link *link, int fd,
@@ -172,7 +179,14 @@ struct osmo_stream_cli;
 typedef int (*osmo_stream_cli_connect_cb_t)(struct osmo_stream_cli *cli);
 typedef int (*osmo_stream_cli_disconnect_cb_t)(struct osmo_stream_cli *cli);
 typedef int (*osmo_stream_cli_read_cb_t)(struct osmo_stream_cli *cli);
-typedef int (*osmo_stream_cli_read_cb2_t)(struct osmo_stream_cli *cli, struct msgb *msg);
+
+/*! Completion call-back function when something was read from from the stream client socket.
+ * \param[in] cli Stream Client that got receive event.
+ * \param[in] res return value of the read()/recvmsg()/... call, or -errno in case of error.
+ * \param[in] msg message buffer containing the read data. Ownership is transferred to the
+ * call-back, and it must make sure to msgb_free() it eventually! */
+typedef int (*osmo_stream_cli_read_cb2_t)(struct osmo_stream_cli *cli, int res, struct msgb *msg);
+
 typedef int (*osmo_stream_cli_segmentation_cb_t)(struct msgb *msg);
 
 void osmo_stream_cli_set_name(struct osmo_stream_cli *cli, const char *name);

src/stream_cli.c

@@ -448,14 +448,23 @@ static void stream_cli_iofd_read_cb(struct osmo_io_fd *iofd, int res, struct msg
 		stream_cli_handle_connecting(cli, res);
 		break;
 	case STREAM_CLI_STATE_CONNECTED:
-		if (res <= 0) {
-			LOGSCLI(cli, LOGL_NOTICE, "received result %d in response to read\n", res);
+		switch (res) {
+		case -EPIPE:
+		case -ECONNRESET:
+			LOGSCLI(cli, LOGL_ERROR, "lost connection with srv (%d)\n", res);
 			osmo_stream_cli_reconnect(cli);
-			msgb_free(msg);
+			break;
+		case 0:
+			LOGSCLI(cli, LOGL_NOTICE, "connection closed with srv\n");
+			osmo_stream_cli_reconnect(cli);
+			break;
+		default:
+			LOGSCLI(cli, LOGL_DEBUG, "received %d bytes from srv\n", res);
 			break;
 		}
+		/* Notify user of new data or error: */
 		if (cli->iofd_read_cb)
-			cli->iofd_read_cb(cli, msg);
+			cli->iofd_read_cb(cli, res, msg);
 		else
 			msgb_free(msg);
 		break;
@@ -503,15 +512,22 @@ static void stream_cli_iofd_recvmsg_cb(struct osmo_io_fd *iofd, int res, struct
 		stream_cli_handle_connecting(cli, res);
 		break;
 	case STREAM_CLI_STATE_CONNECTED:
-		if (res <= 0) {
-			LOGSCLI(cli, LOGL_NOTICE, "received result %d in response to recvmsg\n", res);
+		switch (res) {
+		case -EPIPE:
+		case -ECONNRESET:
+			LOGSCLI(cli, LOGL_ERROR, "lost connection with srv (%d)\n", res);
 			osmo_stream_cli_reconnect(cli);
-			msgb_free(msg);
+			break;
+		case 0:
+			LOGSCLI(cli, LOGL_NOTICE, "connection closed with srv\n");
+			osmo_stream_cli_reconnect(cli);
+			break;
+		default:
 			break;
 		}
-		/* Forward message to read callback, also if the connection failed. */
+		/* Notify user of new data or error: */
 		if (cli->iofd_read_cb)
-			cli->iofd_read_cb(cli, msg);
+			cli->iofd_read_cb(cli, res, msg);
 		else
 			msgb_free(msg);
 		break;

src/stream_srv.c

@@ -611,26 +611,31 @@ struct osmo_stream_srv {
 static void stream_srv_iofd_read_cb(struct osmo_io_fd *iofd, int res, struct msgb *msg)
 {
 	struct osmo_stream_srv *conn = osmo_iofd_get_data(iofd);
-	LOGSSRV(conn, LOGL_DEBUG, "message received (res=%d)\n", res);
 
-	if (OSMO_UNLIKELY(res <= 0)) {
-		/* This connection is dead, destroy it. */
-		msgb_free(msg);
-		osmo_stream_srv_destroy(conn);
-	} else {
-		if (conn->flags & OSMO_STREAM_SRV_F_FLUSH_DESTROY) {
-			LOGSSRV(conn, LOGL_INFO, "Connection is being flushed and closed; ignoring received message\n");
-			msgb_free(msg);
-			if (osmo_iofd_txqueue_len(iofd) == 0)
-				osmo_stream_srv_destroy(conn);
-			return;
-		}
-
-		if (conn->iofd_read_cb)
-			conn->iofd_read_cb(conn, msg);
-		else
-			msgb_free(msg);
+	switch (res) {
+	case -EPIPE:
+	case -ECONNRESET:
+		LOGSSRV(conn, LOGL_ERROR, "lost connection with client (%d)\n", res);
+		break;
+	case 0:
+		LOGSSRV(conn, LOGL_NOTICE, "connection closed with client\n");
+		break;
+	default:
+		LOGSSRV(conn, LOGL_DEBUG, "received %d bytes from client\n", res);
+		break;
 	}
+	if (OSMO_UNLIKELY(conn->flags & OSMO_STREAM_SRV_F_FLUSH_DESTROY)) {
+		LOGSSRV(conn, LOGL_INFO, "Connection is being flushed and closed; ignoring received message\n");
+		msgb_free(msg);
+		if (osmo_iofd_txqueue_len(iofd) == 0)
+			osmo_stream_srv_destroy(conn);
+		return;
+	}
+
+	if (conn->iofd_read_cb)
+		conn->iofd_read_cb(conn, res, msg);
+	else
+		msgb_free(msg);
 }
 
 static void stream_srv_iofd_write_cb(struct osmo_io_fd *iofd, int res, struct msgb *msg)
@@ -658,27 +663,32 @@ static void stream_srv_iofd_recvmsg_cb(struct osmo_io_fd *iofd, int res, struct
 	LOGSSRV(conn, LOGL_DEBUG, "message received (res=%d)\n", res);
 
 	res = stream_iofd_sctp_recvmsg_trailer(iofd, msg, res, msgh);
-	if (res == -EAGAIN)
-		return;
 
-	if (OSMO_UNLIKELY(res <= 0)) {
-		/* This connection is dead, destroy it. */
-		msgb_free(msg);
-		osmo_stream_srv_destroy(conn);
-	} else {
-		if (conn->flags & OSMO_STREAM_SRV_F_FLUSH_DESTROY) {
-			LOGSSRV(conn, LOGL_INFO, "Connection is being flushed and closed; ignoring received message\n");
-			msgb_free(msg);
-			if (osmo_iofd_txqueue_len(iofd) == 0)
-				osmo_stream_srv_destroy(conn);
-			return;
-		}
-
-		if (conn->iofd_read_cb)
-			conn->iofd_read_cb(conn, msg);
-		else
-			msgb_free(msg);
+	switch (res) {
+	case -EPIPE:
+	case -ECONNRESET:
+		LOGSSRV(conn, LOGL_ERROR, "lost connection with client (%d)\n", res);
+		break;
+	case 0:
+		LOGSSRV(conn, LOGL_NOTICE, "connection closed with client\n");
+		break;
+	default:
+		if (OSMO_LIKELY(res > 0))
+			LOGSSRV(conn, LOGL_DEBUG, "received %u bytes from client\n", res);
+		break;
 	}
+	if (OSMO_UNLIKELY(conn->flags & OSMO_STREAM_SRV_F_FLUSH_DESTROY)) {
+		LOGSSRV(conn, LOGL_INFO, "Connection is being flushed and closed; ignoring received message\n");
+		msgb_free(msg);
+		if (osmo_iofd_txqueue_len(iofd) == 0)
+			osmo_stream_srv_destroy(conn);
+		return;
+	}
+
+	if (conn->iofd_read_cb)
+		conn->iofd_read_cb(conn, res, msg);
+	else
+		msgb_free(msg);
 }
 
 static const struct osmo_io_ops srv_ioops_sctp = {

tests/stream/stream_test.c

@@ -502,12 +502,19 @@ static void send_last_third(void *osmo_stream_cli_arg)
 
 static struct osmo_timer_list fragmented_send_tl_cli;
 
-static int test_segm_ipa_stream_srv_cli_read_cb(struct osmo_stream_cli *osc, struct msgb *msg)
+static int test_segm_ipa_stream_srv_cli_read_cb(struct osmo_stream_cli *osc, int res, struct msgb *msg)
 {
 	unsigned char *data;
 	struct ipa_head *h = (struct ipa_head *) msg->l1h;
 	uint8_t ipac_msg_type = *msg->data;
 	struct msgb *reply;
+
+	if (res < 0) {
+		fprintf(stderr, "cannot receive message (res = %d)\n", res);
+		msgb_free(msg);
+		return -ENOMSG;
+	}
+
 	LOGCLI(osc, "Received message from stream (payload len = %" PRIu16 ")\n", msgb_length(msg));
 	if (ipac_msg_type < 0 || 5 < ipac_msg_type) {
 		fprintf(stderr, "Received unexpected IPAC message type %"PRIu8"\n", ipac_msg_type);
@@ -566,7 +573,7 @@ struct osmo_stream_cli *test_segm_ipa_stream_srv_run_client(void *ctx)
 	return osc;
 }
 
-int test_segm_ipa_stream_srv_srv_read_cb(struct osmo_stream_srv *conn, struct msgb *msg)
+int test_segm_ipa_stream_srv_srv_read_cb(struct osmo_stream_srv *conn, int res, struct msgb *msg)
 {
 	static unsigned msgnum_srv = 0;
 	struct ipa_head *ih = (struct ipa_head *)msg->l1h;
@@ -574,6 +581,16 @@ int test_segm_ipa_stream_srv_srv_read_cb(struct osmo_stream_srv *conn, struct ms
 	struct msgb *m;
 	uint8_t msgt;
 
+	if (res <= 0) {
+		if (res < 0)
+			LOGSRV(conn, "cannot receive message: %s\n", strerror(-res));
+		else
+			LOGSRV(conn, "client closed connection\n");
+		msgb_free(msg);
+		osmo_stream_srv_destroy(conn);
+		return -EBADF;
+	}
+
 	LOGSRV(conn, "[%u-srv] Received IPA message from stream (payload len = %" PRIu16 ")\n",
 	       ++msgnum_srv, msgb_length(msg));
 	LOGSRV(conn, "\tmsg buff data (including stripped headers): %s\n",
@@ -699,12 +716,26 @@ static void send_last_third_srv(void *osmo_stream_srv_arg)
 	osmo_timer_schedule(&fragmented_send_tl_srv_destroy, 0, 2);
 }
 
-int test_segm_ipa_stream_cli_srv_read_cb(struct osmo_stream_srv *conn, struct msgb *msg)
+int test_segm_ipa_stream_cli_srv_read_cb(struct osmo_stream_srv *conn, int res, struct msgb *msg)
 {
 	unsigned char *data;
 	struct ipa_head *h = (struct ipa_head *) msg->l1h;
-	uint8_t ipa_msg_type = ((uint8_t *)h)[sizeof(struct ipa_head)];
-	struct msgb *reply = msgb_alloc_headroom(128, 0, "IPA reply");
+	uint8_t ipa_msg_type;
+	struct msgb *reply;
+
+	if (res <= 0) {
+		if (res < 0)
+			LOGSRV(conn, "cannot receive message: %s\n", strerror(-res));
+		else
+			LOGSRV(conn, "client closed connection\n");
+		msgb_free(msg);
+		osmo_stream_srv_destroy(conn);
+		return -EBADF;
+	}
+
+	ipa_msg_type = ((uint8_t *)h)[sizeof(struct ipa_head)];
+
+	reply = msgb_alloc_headroom(128, 0, "IPA reply");
 	if (reply == NULL) {
 		fprintf(stderr, "Cannot allocate message\n");
 		return -ENOMEM;
@@ -778,7 +809,7 @@ static int test_segm_ipa_stream_cli_srv_accept_cb(struct osmo_stream_srv_link *s
 
 static bool test_segm_ipa_stream_cli_all_msgs_processed = false;
 
-static int test_segm_ipa_stream_cli_cli_read_cb(struct osmo_stream_cli *osc, struct msgb *msg)
+static int test_segm_ipa_stream_cli_cli_read_cb(struct osmo_stream_cli *osc, int res, struct msgb *msg)
 {
 	static unsigned msgnum_cli = 0;
 	unsigned char *data;