diff mbox series

[v4] alfred: introduce 'server status' IPC call

Message ID 20220220183614.54865-1-mareklindner@neomailbox.ch
State Accepted, archived
Delegated to: Simon Wunderlich
Headers show
Series [v4] alfred: introduce 'server status' IPC call | expand

Commit Message

Marek Lindner Feb. 20, 2022, 6:36 p.m. UTC
The 'server status' call exports the 'mode' as well as interface
status via IPC. Both parameters can be modified at runtime via the
IPC and as such, the current configuration is dynamic and not
necessarily obvious.

The server status 'request' and 'reply' packet types are added
to allow the IPC client to initiate the status retrieval. The
server will respond with the 'reply' message.

The information is encapsulated in TLV data chunks allowing for
future backward compatible extension of the server status call.

Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>
---
v4:
 - buffer safety checks in server code
 - move tlv type definitions into packet header
 - version checks for sub tlv
v3:
 - close client socket at the end of unix_sock_server_status()

 alfred.h     |   5 +++
 client.c     | 120 +++++++++++++++++++++++++++++++++++++++++++++++++++
 main.c       |   9 +++-
 man/alfred.8 |   3 ++
 packet.h     |  68 +++++++++++++++++++++++++++++
 unix_sock.c  | 106 +++++++++++++++++++++++++++++++++++++++++++++
 6 files changed, 310 insertions(+), 1 deletion(-)

Comments

Sven Eckelmann Feb. 21, 2022, 9:14 a.m. UTC | #1
On Sunday, 20 February 2022 19:36:14 CET Marek Lindner wrote:
> diff --git a/alfred.h b/alfred.h
> index 9ab92a2..598d38b 100644
> --- a/alfred.h
> +++ b/alfred.h
> @@ -33,6 +33,9 @@
>  #define FIXED_TLV_LEN(__tlv_type) \
>         htons(sizeof(__tlv_type) - sizeof(__tlv_type.header))
>  
> +#define FIXED_TLV_LEN_PTR(__tlv_type) \
> +       htons(sizeof(*__tlv_type) - sizeof(__tlv_type->header))
> +

This doesn't apply on master. And also doesn't make a lot of sense, because 
you can now just use FIXED_TLV_LEN(*whatever). So I have dropped this part and 
applied the rest.

Btw. good that you've spotted some prints to stderr which should actually be 
to stdout. You only missed it for "mode: unknown". I have also fixed this.

Kind regards,
	Sven
Marek Lindner Feb. 21, 2022, 11:19 p.m. UTC | #2
On Monday, 21 February 2022 10:14:18 CET Sven Eckelmann wrote:
> On Sunday, 20 February 2022 19:36:14 CET Marek Lindner wrote:
> > diff --git a/alfred.h b/alfred.h
> > index 9ab92a2..598d38b 100644
> > --- a/alfred.h
> > +++ b/alfred.h
> > @@ -33,6 +33,9 @@
> > #define FIXED_TLV_LEN(__tlv_type) \
> > htons(sizeof(__tlv_type) - sizeof(__tlv_type.header))
> > 
> > +#define FIXED_TLV_LEN_PTR(__tlv_type) \
> > +       htons(sizeof(*__tlv_type) - sizeof(__tlv_type->header))
> > +
> 
> This doesn't apply on master. And also doesn't make a lot of sense, because
> you can now just use FIXED_TLV_LEN(*whatever). So I have dropped this part
> and applied the rest.

Your proposal did no compile and the master branch now also does not compile
on ipq40xx:

unix_sock.c: In function 'unix_sock_server_status':
alfred.h:34:46: error: 'status_op_mode' is a pointer; did you mean to use '->'?
  htons(sizeof(__tlv_type) - sizeof(__tlv_type.header))


> Btw. good that you've spotted some prints to stderr which should actually be
> to stdout. You only missed it for "mode: unknown". 

The alfred server running not in primary and not in secondary mode was stderr
worthy for me. But I also don't feel strongly about this.

Cheers,
Marek
Sven Eckelmann Feb. 21, 2022, 11:23 p.m. UTC | #3
On Tuesday, 22 February 2022 00:19:43 CET Marek Lindner wrote:
> Your proposal did no compile and the master branch now also does not compile
> on ipq40xx:
> 
> unix_sock.c: In function 'unix_sock_server_status':
> alfred.h:34:46: error: 'status_op_mode' is a pointer; did you mean to use '->'?
>   htons(sizeof(__tlv_type) - sizeof(__tlv_type.header))

Are you sure you are using the master branch? Because the macro looks quite 
different to what you are showing here. See
https://git.open-mesh.org/alfred.git/blob/5a7d28b1866d1ba13f570551cea177187f9e54ff:/alfred.h#l33
and the commit
https://git.open-mesh.org/alfred.git/commit/f9cf9d22c8bdc8c675c5080d9a26a21082aa1d77 which changed the macro.

Kind regards,
	Sven
diff mbox series

Patch

diff --git a/alfred.h b/alfred.h
index 9ab92a2..598d38b 100644
--- a/alfred.h
+++ b/alfred.h
@@ -33,6 +33,9 @@ 
 #define FIXED_TLV_LEN(__tlv_type) \
 	htons(sizeof(__tlv_type) - sizeof(__tlv_type.header))
 
+#define FIXED_TLV_LEN_PTR(__tlv_type) \
+	htons(sizeof(*__tlv_type) - sizeof(__tlv_type->header))
+
 enum data_source {
 	SOURCE_LOCAL = 0,
 	SOURCE_FIRST_HAND = 1,
@@ -93,6 +96,7 @@  enum clientmode {
 	CLIENT_MODESWITCH,
 	CLIENT_CHANGE_INTERFACE,
 	CLIENT_CHANGE_BAT_IFACE,
+	CLIENT_SERVER_STATUS,
 };
 
 struct interface {
@@ -155,6 +159,7 @@  int alfred_client_set_data(struct globals *globals);
 int alfred_client_modeswitch(struct globals *globals);
 int alfred_client_change_interface(struct globals *globals);
 int alfred_client_change_bat_iface(struct globals *globals);
+int alfred_client_server_status(struct globals *globals);
 /* recv.c */
 int recv_alfred_packet(struct globals *globals, struct interface *interface,
 		       int recv_sock);
diff --git a/client.c b/client.c
index b5d8943..ab4bba6 100644
--- a/client.c
+++ b/client.c
@@ -325,3 +325,123 @@  int alfred_client_change_bat_iface(struct globals *globals)
 
 	return 0;
 }
+
+int alfred_client_server_status(struct globals *globals)
+{
+	struct alfred_server_status_net_iface_v0 *status_net_iface;
+	struct alfred_server_status_bat_iface_v0 *status_bat_iface;
+	struct alfred_server_status_op_mode_v0 *status_op_mode;
+	struct alfred_server_status_req_v0 status_req;
+	struct alfred_server_status_rep_v0 *status_rep;
+	int ret, tlvsize, headsize, len, consumed;
+	struct alfred_tlv *status_tlv;
+	uint8_t buf[MAX_PAYLOAD];
+
+	if (unix_sock_open_client(globals))
+		return -1;
+
+	len = sizeof(status_req);
+	memset(&status_req, 0, len);
+
+	status_req.header.type = ALFRED_SERVER_STATUS;
+	status_req.header.version = ALFRED_VERSION;
+	status_req.header.length = 0;
+
+	ret = write(globals->unix_sock, (unsigned char *)&status_req, len);
+	if (ret != len)
+		fprintf(stderr, "%s: only wrote %d of %d bytes: %s\n",
+			__func__, ret, len, strerror(errno));
+
+	len = read(globals->unix_sock, buf, sizeof(buf));
+	if (len <= 0) {
+		perror("read from unix socket failed");
+		goto err;
+	}
+
+	ret = -1;
+	status_rep = (struct alfred_server_status_rep_v0 *)buf;
+
+	/* drop too small packets */
+	headsize = sizeof(status_rep->header);
+	if (len < headsize) {
+		perror("unexpected header size received from unix socket");
+		goto err;
+	}
+
+	if ((len - headsize) < ((int)ntohs(status_rep->header.length))) {
+		perror("unexpected packet size received from unix socket");
+		goto err;
+	}
+
+	if (status_rep->header.version != ALFRED_VERSION) {
+		perror("alfred version mismatch");
+		goto err;
+	}
+
+	headsize = ntohs(status_rep->header.length);
+
+	if (headsize < (int)(sizeof(*status_rep) - sizeof(status_rep->header)))
+		goto err;
+
+	consumed = sizeof(*status_rep);
+
+	while (len - consumed > 0) {
+		if (len - consumed < (int)sizeof(*status_tlv))
+			break;
+
+		status_tlv = (struct alfred_tlv *)(buf + consumed);
+
+		if (status_tlv->version != ALFRED_VERSION)
+			break;
+
+		tlvsize = ntohs(status_tlv->length);
+		tlvsize += sizeof(*status_tlv);
+
+		if (len - consumed < tlvsize)
+			break;
+
+		switch (status_tlv->type) {
+		case ALFRED_SERVER_OP_MODE:
+			if (tlvsize != sizeof(*status_op_mode))
+				break;
+
+			status_op_mode = (struct alfred_server_status_op_mode_v0 *)(buf + consumed);
+
+			switch (status_op_mode->mode) {
+			case ALFRED_MODESWITCH_SECONDARY:
+				fprintf(stdout, "- mode: secondary\n");
+				break;
+			case ALFRED_MODESWITCH_PRIMARY:
+				fprintf(stdout, "- mode: primary\n");
+				break;
+			default:
+				fprintf(stderr, "- mode: unknown\n");
+				break;
+			}
+
+			break;
+		case ALFRED_SERVER_NET_IFACE:
+			if (tlvsize != sizeof(*status_net_iface))
+				break;
+
+			status_net_iface = (struct alfred_server_status_net_iface_v0 *)(buf + consumed);
+			fprintf(stdout, "- interface: %s\n", status_net_iface->net_iface);
+			fprintf(stdout, "\t- status: %s\n",
+				status_net_iface->active == 1 ? "active" : "inactive");
+			break;
+		case ALFRED_SERVER_BAT_IFACE:
+			if (tlvsize != sizeof(*status_bat_iface))
+				break;
+
+			status_bat_iface = (struct alfred_server_status_bat_iface_v0 *)(buf + consumed);
+			fprintf(stdout, "- batman-adv interface: %s\n", status_bat_iface->bat_iface);
+			break;
+		}
+
+		consumed += tlvsize;
+	}
+
+err:
+	unix_sock_close(globals);
+	return 0;
+}
diff --git a/main.c b/main.c
index d40a0cc..68d6efd 100644
--- a/main.c
+++ b/main.c
@@ -38,6 +38,7 @@  static void alfred_usage(void)
 	printf("                   secondary          switch daemon to mode secondary\n");
 	printf("  -I, --change-interface [interface]  change to the specified interface(s)\n");
 	printf("  -B, --change-bat-iface [interface]  change to the specified batman-adv interface\n");
+	printf("  -S, --server-status                 request server status info such as mode & interfaces\n");
 	printf("\n");
 	printf("server mode options:\n");
 	printf("  -i, --interface                     specify the interface (or comma separated list of interfaces) to listen on\n");
@@ -162,6 +163,7 @@  static struct globals *alfred_init(int argc, char *argv[])
 		{"modeswitch",		required_argument,	NULL,	'M'},
 		{"change-interface",	required_argument,	NULL,	'I'},
 		{"change-bat-iface",	required_argument,	NULL,	'B'},
+		{"server-status",	required_argument,	NULL,	'S'},
 		{"unix-path",		required_argument,	NULL,	'u'},
 		{"update-command",	required_argument,	NULL,	'c'},
 		{"version",		no_argument,		NULL,	'v'},
@@ -196,7 +198,7 @@  static struct globals *alfred_init(int argc, char *argv[])
 
 	time_random_seed();
 
-	while ((opt = getopt_long(argc, argv, "ms:r:hi:b:vV:M:I:B:u:dc:p:4:f", long_options,
+	while ((opt = getopt_long(argc, argv, "ms:r:hi:b:vV:M:I:B:Su:dc:p:4:f", long_options,
 				  &opt_ind)) != -1) {
 		switch (opt) {
 		case 'r':
@@ -258,6 +260,9 @@  static struct globals *alfred_init(int argc, char *argv[])
 			globals->clientmode = CLIENT_CHANGE_BAT_IFACE;
 			globals->mesh_iface = strdup(optarg);
 			break;
+		case 'S':
+			globals->clientmode = CLIENT_SERVER_STATUS;
+			break;
 		case 'u':
 			globals->unix_path = optarg;
 			break;
@@ -321,6 +326,8 @@  int main(int argc, char *argv[])
 		return alfred_client_change_interface(globals);
 	case CLIENT_CHANGE_BAT_IFACE:
 		return alfred_client_change_bat_iface(globals);
+	case CLIENT_SERVER_STATUS:
+		return alfred_client_server_status(globals);
 	}
 
 	return 0;
diff --git a/man/alfred.8 b/man/alfred.8
index 74814e0..cf0eafc 100644
--- a/man/alfred.8
+++ b/man/alfred.8
@@ -94,6 +94,9 @@  Change the alfred server to use the new \fBinterface\fP(s)
 .TP
 \fB\-B\fP, \fB\-\-change\-bat\-iface\fP \fIinterface\fP
 Change the alfred server to use the new \fBbatman-adv interface\fP
+.TP
+\fB\-S\fP, \fB\-\-server\-status\fP
+Request server status information such as mode & interfaces\fP
 .
 .SH SERVER OPTIONS
 .TP
diff --git a/packet.h b/packet.h
index 94c6a77..0c1a2eb 100644
--- a/packet.h
+++ b/packet.h
@@ -69,6 +69,7 @@  enum alfred_packet_type {
 	ALFRED_MODESWITCH = 5,
 	ALFRED_CHANGE_INTERFACE = 6,
 	ALFRED_CHANGE_BAT_IFACE = 7,
+	ALFRED_SERVER_STATUS = 8,
 };
 
 /* packets */
@@ -159,6 +160,73 @@  struct alfred_change_interface_v0 {
 struct alfred_change_bat_iface_v0 {
 	struct alfred_tlv header;
 	char bat_iface[IFNAMSIZ];
+};
+
+/**
+ * enum alfred_packet_type - Types of packet stored in the main alfred_tlv
+ * @ALFRED_SERVER_MODE: Contains alfred mode information*
+ * @ALFRED_SERVER_NET_IFACE: Contains alfred network interface information*
+ * @ALFRED_SERVER_BAT_IFACE: Contains alfred batman interface information*
+ */
+enum alfred_server_status_type {
+	ALFRED_SERVER_OP_MODE = 0,
+	ALFRED_SERVER_NET_IFACE = 1,
+	ALFRED_SERVER_BAT_IFACE = 2,
+};
+
+/**
+ * struct alfred_server_status_req_v0 - server status request
+ * @header: TLV header describing the complete packet
+ *
+ * Sent to the daemon by client
+ */
+struct alfred_server_status_req_v0 {
+	struct alfred_tlv header;
+} __packed;
+
+/**
+ * struct alfred_server_status_op_mode_v0 - server op mode status information
+ * @op_mode: active op mode
+ *
+ * Sent to the client by daemon in response to status request
+ */
+struct alfred_server_status_op_mode_v0 {
+	struct alfred_tlv header;
+	uint8_t mode;
+} __packed;
+
+/**
+ * struct alfred_server_status_net_iface_v0 - server net iface status information
+ * @net_iface: configured network interface
+ * @active: network interface active/inactive status info
+ *
+ * Sent to the client by daemon in response to status request
+ */
+struct alfred_server_status_net_iface_v0 {
+	struct alfred_tlv header;
+	char net_iface[IFNAMSIZ];
+	uint8_t active;
+} __packed;
+
+/**
+ * struct alfred_server_status_bat_iface_v0 - server bat iface status information
+ * @op_mode: configured batman interface
+ *
+ * Sent to the client by daemon in response to status request
+ */
+struct alfred_server_status_bat_iface_v0 {
+	struct alfred_tlv header;
+	char bat_iface[IFNAMSIZ];
+} __packed;
+
+/**
+ * struct alfred_server_status_rep_v0 - server status reply
+ * @header: TLV header describing the complete packet
+ *
+ * Sent by the daemon to client in response to status request
+ */
+struct alfred_server_status_rep_v0 {
+	struct alfred_tlv header;
 } __packed;
 
 /**
diff --git a/unix_sock.c b/unix_sock.c
index bc39199..a5a0196 100644
--- a/unix_sock.c
+++ b/unix_sock.c
@@ -366,6 +366,109 @@  err:
 	return ret;
 }
 
+static int unix_sock_server_status(struct globals *globals, int client_sock)
+{
+	struct alfred_server_status_net_iface_v0 *status_net_iface;
+	struct alfred_server_status_bat_iface_v0 *status_bat_iface;
+	struct alfred_server_status_op_mode_v0 *status_op_mode;
+	struct alfred_server_status_rep_v0 *status_rep;
+	struct interface *interface;
+	uint8_t buf[MAX_PAYLOAD];
+	int ret = -1;
+	int len = 0;
+
+	/* too large? - should never happen */
+	if (sizeof(*status_rep) + len > sizeof(buf)) {
+		fprintf(stderr, "ERROR: send buffer too small for server_status\n");
+		goto err;
+	}
+
+	status_rep = (struct alfred_server_status_rep_v0 *)buf;
+	status_rep->header.type = ALFRED_SERVER_STATUS;
+	status_rep->header.version = ALFRED_VERSION;
+
+	len += sizeof(*status_rep);
+
+	/* too large? - should never happen */
+	if (sizeof(*status_op_mode) + len > sizeof(buf)) {
+		fprintf(stderr, "ERROR: send buffer too small for server_status op_mode\n");
+		goto err;
+	}
+
+	status_op_mode = (struct alfred_server_status_op_mode_v0 *)(buf + len);
+	status_op_mode->header.type = ALFRED_SERVER_OP_MODE;
+	status_op_mode->header.version = ALFRED_VERSION;
+	status_op_mode->header.length = FIXED_TLV_LEN_PTR(status_op_mode);
+
+	switch (globals->opmode) {
+	case OPMODE_SECONDARY:
+		status_op_mode->mode = ALFRED_MODESWITCH_SECONDARY;
+		break;
+	case OPMODE_PRIMARY:
+		status_op_mode->mode = ALFRED_MODESWITCH_PRIMARY;
+		break;
+	default:
+		break;
+	}
+
+	len += sizeof(*status_op_mode);
+
+	list_for_each_entry(interface, &globals->interfaces, list) {
+		/* too large? - should never happen */
+		if (sizeof(*status_net_iface) + len > sizeof(buf)) {
+			fprintf(stderr, "ERROR: send buffer too small for server_status iface\n");
+			goto err;
+		}
+
+		status_net_iface = (struct alfred_server_status_net_iface_v0 *)(buf + len);
+		status_net_iface->header.type = ALFRED_SERVER_NET_IFACE;
+		status_net_iface->header.version = ALFRED_VERSION;
+		status_net_iface->header.length = FIXED_TLV_LEN_PTR(status_net_iface);
+
+		strncpy(status_net_iface->net_iface, interface->interface,
+			sizeof(status_net_iface->net_iface));
+		status_net_iface->net_iface[sizeof(status_net_iface->net_iface) - 1] = '\0';
+		if (interface->netsock > -1)
+			status_net_iface->active = 1;
+		else
+			status_net_iface->active = 0;
+
+		len += sizeof(*status_net_iface);
+	}
+
+	/* too large? - should never happen */
+	if (sizeof(*status_bat_iface) + len > sizeof(buf)) {
+		fprintf(stderr, "ERROR: send buffer too small for server_status bat_iface\n");
+		goto err;
+	}
+
+	status_bat_iface = (struct alfred_server_status_bat_iface_v0 *)(buf + len);
+	status_bat_iface->header.type = ALFRED_SERVER_BAT_IFACE;
+	status_bat_iface->header.version = ALFRED_VERSION;
+	status_bat_iface->header.length = FIXED_TLV_LEN_PTR(status_bat_iface);
+
+	strncpy(status_bat_iface->bat_iface, globals->mesh_iface,
+		sizeof(status_bat_iface->bat_iface));
+	status_bat_iface->bat_iface[sizeof(status_bat_iface->bat_iface) - 1] = '\0';
+
+	len += sizeof(*status_bat_iface);
+	status_rep->header.length = htons(len - sizeof(status_rep->header));
+
+	ret = write(client_sock, buf, len);
+	if (ret != len) {
+		fprintf(stderr, "%s: only wrote %d of %d bytes: %s\n",
+			__func__, ret, len, strerror(errno));
+		ret = -1;
+		goto err;
+	}
+
+	ret = 0;
+
+err:
+	close(client_sock);
+	return ret;
+}
+
 int unix_sock_read(struct globals *globals)
 {
 	int client_sock;
@@ -428,6 +531,9 @@  int unix_sock_read(struct globals *globals)
 						 (struct alfred_change_bat_iface_v0 *)packet,
 						 client_sock);
 		break;
+	case ALFRED_SERVER_STATUS:
+		ret = unix_sock_server_status(globals, client_sock);
+		break;
 	default:
 		/* unknown packet type */
 		ret = -1;