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refactor: move RESET Osmux TLV parsing to ran_msg_a.c 

ran_peer.c is not the proper place to parse messages, because it should be RAN
agnostic. All parsing and encoding belongs in ran_msg_a.c and ran_msg_iu.c.

Move the Osmux TLV parsing into the is_reset_msg op: add supports_osmux
out-parameter (and add a logging fi pointer). To be able to modify msg->l3h,
also make the msgb arg non-const.

In ranap_is_reset_msg(), always return non-support for Osmux.

In bssmap_is_reset_msg(), return 0 if no TLVs were parsed, 1/-1 if an Osmux TLV
was present/not present.

Update the osmux support flag directly where the ConnectionLess message is
received, so that there is only one place responsible for that.

Related: OS#4595
Change-Id: I1ad4a3f9356216dd4bf8c48fba29fd23438810a7
This commit is contained in:
Neels Hofmeyr 2020-06-26 15:20:51 +02:00
parent 1139ca352b
commit b697274daa
6 changed files with 60 additions and 26 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
include/osmocom/msc/ran_msg_a.h
View File

@ -35,7 +35,8 @@ struct gsm_mncc_bearer_cap;
int ran_a_decode_l2(struct ran_dec *ran_a, struct msgb *bssap);
struct msgb *ran_a_encode(struct osmo_fsm_inst *caller_fi, const struct ran_msg *ran_enc_msg);
enum reset_msg_type bssmap_is_reset_msg(const struct sccp_ran_inst *sri, const struct msgb *l2);
enum reset_msg_type bssmap_is_reset_msg(const struct sccp_ran_inst *sri, struct osmo_fsm_inst *log_fi,
struct msgb *l2, int *supports_osmux);
struct msgb *bssmap_make_reset_msg(const struct sccp_ran_inst *sri, enum reset_msg_type type);
struct msgb *bssmap_make_paging_msg(const struct sccp_ran_inst *sri, const struct gsm0808_cell_id *page_cell_id,
const char *imsi, uint32_t tmsi, enum paging_cause cause);

3
include/osmocom/msc/ran_msg_iu.h
View File

@ -28,7 +28,8 @@
int ran_iu_decode_l2(struct ran_dec *ran_dec_iu, struct msgb *ranap);
struct msgb *ran_iu_encode(struct osmo_fsm_inst *caller_fi, const struct ran_msg *ran_enc_msg);
enum reset_msg_type ranap_is_reset_msg(const struct sccp_ran_inst *sri, const struct msgb *l2);
enum reset_msg_type ranap_is_reset_msg(const struct sccp_ran_inst *sri, struct osmo_fsm_inst *log_fi,
struct msgb *l2, int *supports_osmux);
struct msgb *ranap_make_reset_msg(const struct sccp_ran_inst *sri, enum reset_msg_type type);
struct msgb *ranap_make_paging_msg(const struct sccp_ran_inst *sri, const struct gsm0808_cell_id *page_cell_id,
const char *imsi, uint32_t tmsi, enum paging_cause cause);

7
include/osmocom/msc/sccp_ran.h
View File

@ -233,8 +233,11 @@ struct sccp_ran_ops {
/* Return whether the given l2_cl message is a RESET, RESET ACKNOWLEDGE, or RESET-unrelated message.
* This callback is stored in struct sccp_ran_inst to provide RESET handling to the caller (ran_peer),
* it is not used in sccp_ran.c. */
enum reset_msg_type (* is_reset_msg )(const struct sccp_ran_inst *sri, const struct msgb *l2_cl);
* it is not used in sccp_ran.c.
* In supports_osmux, return 0 for no information, 1 for support detected, -1 for non-support detected.
*/
enum reset_msg_type (* is_reset_msg )(const struct sccp_ran_inst *sri, struct osmo_fsm_inst *log_fi,
struct msgb *l2_cl, int *supports_osmux);
/* Return a RESET or RESET ACK message for this RAN type.
* This callback is stored in struct sccp_ran_inst to provide RESET handling to the caller (ran_peer),

36
src/libmsc/ran_msg_a.c
View File

@ -1275,20 +1275,50 @@ struct msgb *ran_a_encode(struct osmo_fsm_inst *caller_fi, const struct ran_msg
return msg;
}
/* Return 1 for a RESET, 2 for a RESET ACK message, 0 otherwise */
enum reset_msg_type bssmap_is_reset_msg(const struct sccp_ran_inst *sri, const struct msgb *l2)
static void cl_parse_osmux(struct osmo_fsm_inst *log_fi, struct msgb *msg, int *supports_osmux)
{
struct tlv_parsed tp;
int rc;
if (supports_osmux == NULL)
return;
rc = tlv_parse(&tp, gsm0808_att_tlvdef(), msgb_l3(msg) + 1, msgb_l3len(msg) - 1, 0, 0);
if (rc < 0) {
LOGPFSMSL(log_fi, DBSSAP, LOGL_ERROR, "BSSMAP: Failed parsing TLV looking for Osmux support\n");
return;
}
if (TLVP_PRESENT(&tp, GSM0808_IE_OSMO_OSMUX_SUPPORT)) {
*supports_osmux = true;
} else {
*supports_osmux = false;
}
}
/* Return 1 for a RESET, 2 for a RESET ACK message, 0 otherwise.
* In supports_osmux, return 0 for no information, 1 for support detected, -1 for non-support detected. */
enum reset_msg_type bssmap_is_reset_msg(const struct sccp_ran_inst *sri, struct osmo_fsm_inst *log_fi,
struct msgb *l2, int *supports_osmux)
{
struct bssmap_header *bs = (struct bssmap_header *)msgb_l2(l2);
if (supports_osmux != NULL)
*supports_osmux = 0;
if (!bs
|| msgb_l2len(l2) < (sizeof(*bs) + 1)
|| bs->type != BSSAP_MSG_BSS_MANAGEMENT)
return SCCP_RAN_MSG_NON_RESET;
switch (l2->l2h[sizeof(*bs)]) {
l2->l3h = l2->l2h + sizeof(struct bssmap_header);
switch (l2->l3h[0]) {
case BSS_MAP_MSG_RESET:
cl_parse_osmux(log_fi, l2, supports_osmux);
return SCCP_RAN_MSG_RESET;
case BSS_MAP_MSG_RESET_ACKNOWLEDGE:
cl_parse_osmux(log_fi, l2, supports_osmux);
return SCCP_RAN_MSG_RESET_ACK;
default:
return SCCP_RAN_MSG_NON_RESET;

6
src/libmsc/ran_msg_iu.c
View File

@ -438,11 +438,15 @@ static void ranap_handle_cl(void *ctx, ranap_message *message)
}
}
enum reset_msg_type ranap_is_reset_msg(const struct sccp_ran_inst *sri, const struct msgb *l2)
enum reset_msg_type ranap_is_reset_msg(const struct sccp_ran_inst *sri, struct osmo_fsm_inst *log_fi,
struct msgb *l2, int *supports_osmux)
{
int ret = SCCP_RAN_MSG_NON_RESET;
int rc;
if (supports_osmux != NULL)
*supports_osmux = -1;
rc = ranap_cn_rx_cl(ranap_handle_cl, &ret, msgb_l2(l2), msgb_l2len(l2));
if (rc)
return 0;

31
src/libmsc/ran_peer.c
View File

@ -122,25 +122,19 @@ void ran_peer_discard_all_conns(struct ran_peer *rp)
}
}
/* TODO: create an sccp_ran_ops.rx_reset(_ack) to handle this differently on 2g and 3G */
/* We expect RAN peer to provide use with an Osmocom extension TLV in BSSMAP_RESET to
* announce Osmux support */
static void ran_peer_update_osmux_support(struct ran_peer *rp, struct msgb *msg)
static void ran_peer_update_osmux_support(struct ran_peer *rp, int supports_osmux)
{
struct tlv_parsed tp;
int rc;
bool old_value = rp->remote_supports_osmux;
OSMO_ASSERT(msg);
msg->l3h = msg->l2h + sizeof(struct bssmap_header);
rc = tlv_parse(&tp, gsm0808_att_tlvdef(), msg->l3h + 1, msgb_l3len(msg) - 1, 0, 0);
if (rc < 0)
LOG_RAN_PEER(rp, LOGL_NOTICE, "Failed parsing TLV looking for Osmux support\n");
if (TLVP_PRESENT(&tp, GSM0808_IE_OSMO_OSMUX_SUPPORT)) {
switch (supports_osmux) {
case 1:
rp->remote_supports_osmux = true;
} else {
break;
case -1:
rp->remote_supports_osmux = false;
break;
default:
return;
}
if (old_value != rp->remote_supports_osmux)
@ -155,8 +149,6 @@ static void ran_peer_rx_reset(struct ran_peer *rp, struct msgb* msg)
ran_peer_discard_all_conns(rp);
ran_peer_update_osmux_support(rp, msg);
reset_ack = rp->sri->ran->sccp_ran_ops.make_reset_msg(rp->sri, SCCP_RAN_MSG_RESET_ACK);
if (!reset_ack) {
@ -183,7 +175,6 @@ static void ran_peer_rx_reset(struct ran_peer *rp, struct msgb* msg)
static void ran_peer_rx_reset_ack(struct ran_peer *rp, struct msgb* msg)
{
ran_peer_state_chg(rp, RAN_PEER_ST_READY);
ran_peer_update_osmux_support(rp, msg);
}
void ran_peer_reset(struct ran_peer *rp)
@ -213,10 +204,14 @@ void ran_peer_allstate_action(struct osmo_fsm_inst *fi, uint32_t event, void *da
struct ran_peer *rp = fi->priv;
struct ran_peer_ev_ctx *ctx = data;
struct msgb *msg = ctx->msg;
int rc;
int supports_osmux;
switch (event) {
case RAN_PEER_EV_MSG_UP_CL:
switch (rp->sri->ran->sccp_ran_ops.is_reset_msg(rp->sri, msg)) {
rc = rp->sri->ran->sccp_ran_ops.is_reset_msg(rp->sri, fi, msg, &supports_osmux);
ran_peer_update_osmux_support(rp, supports_osmux);
switch (rc) {
case 1:
osmo_fsm_inst_dispatch(fi, RAN_PEER_EV_RX_RESET, msg);
return;