Hi Jolly, all,
I spent some time figuring out why LCR and OpenBSC wouldn't want to work with
each other. The reason was the addition of an element to the MNCC structure. I
propose to send a hello packet down the MNCC socket and leave it to the client
to decide if the version is acceptable.
I will need to move the mncc header to libosmocore as osmocomBB is currently
using a copy of the OpenBSC header.
comments
holger
>From 249543405cc5e4532a3663ed1058349ef4b4989c Mon Sep 17 00:00:00 2001
From: Holger Hans Peter Freyther <[email protected]>
Date: Fri, 21 Oct 2011 14:12:46 +0200
Subject: [PATCH] mncc: Introduce a hello packet that is sent to the client.
Send a hello packet down to the client with the version number
of the MNCC interface. The hello structure might be extended to
include the endianes, size of each structure, etc.
---
openbsc/include/openbsc/mncc.h | 8 ++++++++
openbsc/src/libmsc/mncc_sock.c | 24 ++++++++++++++++++++++++
2 files changed, 32 insertions(+), 0 deletions(-)
diff --git a/openbsc/include/openbsc/mncc.h b/openbsc/include/openbsc/mncc.h
index 8c59fe2..9153d65 100644
--- a/openbsc/include/openbsc/mncc.h
+++ b/openbsc/include/openbsc/mncc.h
@@ -96,6 +96,8 @@ struct gsm_call {
#define GSM_TCHF_FRAME 0x0300
#define GSM_TCHF_FRAME_EFR 0x0301
+#define MNCC_SOCKET_HELLO 0x0400
+
#define GSM_MAX_FACILITY 128
#define GSM_MAX_SSVERSION 128
#define GSM_MAX_USERUSER 128
@@ -158,6 +160,12 @@ struct gsm_data_frame {
unsigned char data[0];
};
+#define MNCC_SOCK_VERSION 1
+struct gsm_mncc_hello {
+ uint32_t msg_type;
+ uint32_t version;
+};
+
char *get_mncc_name(int value);
void mncc_set_cause(struct gsm_mncc *data, int loc, int val);
void cc_tx_to_mncc(struct gsm_network *net, struct msgb *msg);
diff --git a/openbsc/src/libmsc/mncc_sock.c b/openbsc/src/libmsc/mncc_sock.c
index d8caf07..b9ebdb0 100644
--- a/openbsc/src/libmsc/mncc_sock.c
+++ b/openbsc/src/libmsc/mncc_sock.c
@@ -213,6 +213,29 @@ static int mncc_sock_cb(struct osmo_fd *bfd, unsigned int flags)
return rc;
}
+/**
+ * Send a version indication to the remote.
+ */
+static void queue_hello(struct mncc_sock_state *mncc)
+{
+ struct gsm_mncc_hello *hello;
+ struct msgb *msg;
+
+ msg = msgb_alloc(512, "mncc hello");
+ if (!msg) {
+ LOGP(DMNCC, LOGL_ERROR, "Failed to allocate hello.\n");
+ mncc_sock_close(mncc);
+ return;
+ }
+
+ hello = (struct gsm_mncc_hello *) msgb_put(msg, sizeof(*hello));
+ hello->msg_type = MNCC_SOCKET_HELLO;
+ hello->version = MNCC_SOCK_VERSION;
+
+ msgb_enqueue(&mncc->net->upqueue, msg);
+ mncc->conn_bfd.when |= BSC_FD_WRITE;
+}
+
/* accept a new connection */
static int mncc_sock_accept(struct osmo_fd *bfd, unsigned int flags)
{
@@ -253,6 +276,7 @@ static int mncc_sock_accept(struct osmo_fd *bfd, unsigned int flags)
LOGP(DMNCC, LOGL_NOTICE, "MNCC Socket has connection with external "
"call control application\n");
+ queue_hello(state);
return 0;
}
--
1.7.5.4
>From 7a20ab9e551ee3a4fa9fa968a3eb54a2874d6d39 Mon Sep 17 00:00:00 2001
From: Holger Hans Peter Freyther <[email protected]>
Date: Fri, 21 Oct 2011 14:11:04 +0200
Subject: [PATCH] gsm: Verify the MNCC_VERSION of the BSC/MS and close the
socket on mismatch
The BSC/MS will send a Hello packet that includes the version number,
make LCR verify this version number and close the socket in case it
does not match a supported version.
---
gsm.cpp | 12 ++++++++++++
mncc.h | 7 +++++++
2 files changed, 19 insertions(+), 0 deletions(-)
diff --git a/gsm.cpp b/gsm.cpp
index e6806c3..227d618 100644
--- a/gsm.cpp
+++ b/gsm.cpp
@@ -1042,6 +1042,7 @@ static int mncc_fd_read(struct lcr_fd *lfd, void *inst, int idx)
int rc;
static char buf[sizeof(struct gsm_mncc)+1024];
struct gsm_mncc *mncc_prim = (struct gsm_mncc *) buf;
+ struct gsm_mncc_hello *hello = (struct gsm_mncc_hello *) buf;
memset(buf, 0, sizeof(buf));
rc = recv(lfd->fd, buf, sizeof(buf), 0);
@@ -1050,6 +1051,17 @@ static int mncc_fd_read(struct lcr_fd *lfd, void *inst, int idx)
if (rc < 0)
return rc;
+ /* TODO: size check? */
+ switch (mncc_prim->msg_type) {
+ case MNCC_SOCKET_HELLO:
+ if (hello->version != MNCC_SOCK_VERSION) {
+ PERROR("MNCC version different. BSC version is %u\n", hello->version);
+ mncc_fd_close(lcr_gsm, lfd);
+ return 0;
+ }
+ break;
+ }
+
/* Hand the MNCC message into LCR */
switch (lcr_gsm->type) {
#ifdef WITH_GSM_BS
diff --git a/mncc.h b/mncc.h
index e5f8216..fac7145 100644
--- a/mncc.h
+++ b/mncc.h
@@ -56,6 +56,8 @@
#define GSM_TCHF_FRAME 0x0300
#define GSM_TCHF_FRAME_EFR 0x0301
+#define MNCC_SOCKET_HELLO 0x0400
+
#define GSM_MAX_FACILITY 128
#define GSM_MAX_SSVERSION 128
#define GSM_MAX_USERUSER 128
@@ -185,3 +187,8 @@ struct gsm_data_frame {
unsigned char data[0];
};
+#define MNCC_SOCK_VERSION 1
+struct gsm_mncc_hello {
+ u_int32_t msg_type;
+ u_int32_t version;
+};
--
1.7.5.4
