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Adding LLC-XID related modifications in LLC 

With this commit the already existing XID mechanism has been
modified to suit the needs for the upcomming SNDCP-XID patches.

This commit should not break anything since it does not alter
the current behaviour (incoming XID is still just echoed, on
GMM-Reset a basic XID message is still echoed)

Change-Id: I65b9d625e72d3d61c99abdc7041773701d694d52
This commit is contained in:
Philipp Maier 2016-08-10 12:24:09 +02:00 committed by Harald Welte
parent 3ec03d5048
commit 4ac3aee711
3 changed files with 315 additions and 57 deletions
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12
openbsc/include/openbsc/gprs_llc.h
View File

@ -4,6 +4,7 @@
#include <stdint.h>
#include <stdbool.h>
#include <openbsc/gprs_sgsn.h>
#include <openbsc/gprs_llc_xid.h>
/* Section 4.7 LLC Layer Structure */
enum gprs_llc_sapi {
@ -166,6 +167,13 @@ struct gprs_llc_llme {
uint16_t nsei;
struct gprs_llc_lle lle[NUM_SAPIS];
/* Copy of the XID fields we have sent with the last
* network originated XID-Request. Since the phone
* may strip the optional fields in the confirmation
* we need to remeber those fields in order to be
* able to create the compression entity. */
struct llist_head *xid;
/* Internal management */
uint32_t age_timestamp;
};
@ -219,6 +227,10 @@ int gprs_llgmm_reset(struct gprs_llc_llme *llme);
int gprs_llgmm_reset_oldmsg(struct msgb* oldmsg, uint8_t sapi,
struct gprs_llc_llme *llme);
/* Set of LL-XID negotiation (See also: TS 101 351, Section 7.2.2.4) */
int gprs_ll_xid_req(struct gprs_llc_lle *lle,
struct gprs_llc_xid_field *l3_xid_field);
/* 04.64 Chapter 7.2.1.1 LLGMM-ASSIGN */
int gprs_llgmm_assign(struct gprs_llc_llme *llme,
uint32_t old_tlli, uint32_t new_tlli);

359
openbsc/src/gprs/gprs_llc.c
View File

@ -39,8 +39,286 @@
#include <openbsc/gprs_llc.h>
#include <openbsc/crc24.h>
#include <openbsc/sgsn.h>
#include <openbsc/gprs_llc_xid.h>
#include <openbsc/gprs_sndcp.h>
static struct gprs_llc_llme *llme_alloc(uint32_t tlli);
static int gprs_llc_tx_xid(struct gprs_llc_lle *lle, struct msgb *msg,
int command);
static int gprs_llc_tx_u(struct msgb *msg, uint8_t sapi,
int command, enum gprs_llc_u_cmd u_cmd, int pf_bit);
/* BEGIN XID RELATED */
/* Generate XID message */
static int gprs_llc_generate_xid(uint8_t *bytes, int bytes_len,
struct gprs_llc_xid_field *l3_xid_field,
struct gprs_llc_llme *llme)
{
/* Note: Called by gprs_ll_xid_req() */
LLIST_HEAD(xid_fields);
struct gprs_llc_xid_field xid_version;
struct gprs_llc_xid_field xid_n201u;
struct gprs_llc_xid_field xid_n201i;
xid_version.type = GPRS_LLC_XID_T_VERSION;
xid_version.data = (uint8_t *) "\x00";
xid_version.data_len = 1;
xid_n201u.type = GPRS_LLC_XID_T_N201_U;
xid_n201u.data = (uint8_t *) "\x05\xf0";
xid_n201u.data_len = 2;
xid_n201i.type = GPRS_LLC_XID_T_N201_I;
xid_n201i.data = (uint8_t *) "\x05\xf0";
xid_n201i.data_len = 2;
/* Add locally managed XID Fields */
llist_add(&xid_n201i.list, &xid_fields);
llist_add(&xid_n201u.list, &xid_fields);
llist_add(&xid_version.list, &xid_fields);
/* Append layer 3 XID field (if present) */
if (l3_xid_field) {
/* Enforce layer 3 XID type (just to be sure) */
l3_xid_field->type = GPRS_LLC_XID_T_L3_PAR;
/* Add Layer 3 XID field to the list */
llist_add(&l3_xid_field->list, &xid_fields);
}
/* Store generated XID for later reference */
talloc_free(llme->xid);
llme->xid = gprs_llc_copy_xid(llme, &xid_fields);
return gprs_llc_compile_xid(bytes, bytes_len, &xid_fields);
}
/* Generate XID message that will cause the GMM to reset */
static int gprs_llc_generate_xid_for_gmm_reset(uint8_t *bytes,
int bytes_len, uint32_t iov_ui,
struct gprs_llc_llme *llme)
{
/* Called by gprs_llgmm_reset() and
* gprs_llgmm_reset_oldmsg() */
LLIST_HEAD(xid_fields);
struct gprs_llc_xid_field xid_reset;
struct gprs_llc_xid_field xid_iovui;
/* First XID component must be RESET */
xid_reset.type = GPRS_LLC_XID_T_RESET;
xid_reset.data = NULL;
xid_reset.data_len = 0;
/* Add new IOV-UI */
xid_iovui.type = GPRS_LLC_XID_T_IOV_UI;
xid_iovui.data = (uint8_t *) & iov_ui;
xid_iovui.data_len = 4;
/* Add locally managed XID Fields */
llist_add(&xid_iovui.list, &xid_fields);
llist_add(&xid_reset.list, &xid_fields);
/* Store generated XID for later reference */
talloc_free(llme->xid);
llme->xid = gprs_llc_copy_xid(llme, &xid_fields);
return gprs_llc_compile_xid(bytes, bytes_len, &xid_fields);
}
/* Process an incoming XID confirmation */
static int gprs_llc_process_xid_conf(uint8_t *bytes, int bytes_len,
struct gprs_llc_lle *lle)
{
/* Note: This function handles the response of a network originated
* XID-Request. There XID messages reflected by the phone are analyzed
* and processed here. The caller is called by rx_llc_xid(). */
struct llist_head *xid_fields;
struct gprs_llc_xid_field *xid_field;
/* Parse and analyze XID-Response */
xid_fields = gprs_llc_parse_xid(NULL, bytes, bytes_len);
if (xid_fields) {
gprs_llc_dump_xid_fields(xid_fields, LOGL_DEBUG);
llist_for_each_entry(xid_field, xid_fields, list) {
/* Forward SNDCP-XID fields to Layer 3 (SNDCP) */
if (xid_field->type == GPRS_LLC_XID_T_L3_PAR) {
LOGP(DLLC, LOGL_NOTICE,
"Ignoring SNDCP-XID-Field: XID: type=%i, data_len=%i, data=%s\n",
xid_field->type, xid_field->data_len,
osmo_hexdump_nospc(xid_field->data,
xid_field->data_len));
}
/* Process LLC-XID fields: */
else {
/* FIXME: Do something more useful with the
* echoed XID-Information. Currently we
* just ignore the response completely and
* by doing so we blindly accept any changes
* the MS might have done to the our XID
* inquiry. There is a remainig risk of
* malfunction! */
LOGP(DLLC, LOGL_NOTICE,
"Ignoring XID-Field: XID: type=%d, data_len=%d, data=%s\n",
xid_field->type, xid_field->data_len,
osmo_hexdump_nospc(xid_field->data,
xid_field->data_len));
}
}
talloc_free(xid_fields);
}
/* Flush pending XID fields */
talloc_free(lle->llme->xid);
lle->llme->xid = NULL;
return 0;
}
/* Process an incoming XID indication and generate an appropiate response */
static int gprs_llc_process_xid_ind(uint8_t *bytes_request,
int bytes_request_len,
uint8_t *bytes_response,
int bytes_response_maxlen,
struct gprs_llc_lle *lle)
{
/* Note: This function computes the response that is sent back to the
* phone when a phone originated XID is received. The function is
* called by rx_llc_xid() */
int rc = -EINVAL;
struct llist_head *xid_fields;
struct llist_head *xid_fields_response;
struct gprs_llc_xid_field *xid_field;
struct gprs_llc_xid_field *xid_field_response;
/* Flush eventually pending XID fields */
talloc_free(lle->llme->xid);
lle->llme->xid = NULL;
/* Parse and analyze XID-Request */
xid_fields =
gprs_llc_parse_xid(lle->llme, bytes_request, bytes_request_len);
if (xid_fields) {
xid_fields_response = talloc_zero(lle->llme, struct llist_head);
INIT_LLIST_HEAD(xid_fields_response);
gprs_llc_dump_xid_fields(xid_fields, LOGL_DEBUG);
/* Process LLC-XID fields: */
llist_for_each_entry(xid_field, xid_fields, list) {
if (xid_field->type != GPRS_LLC_XID_T_L3_PAR) {
/* FIXME: Check the incoming XID parameters for
* for validity. Currently we just blindly
* accept all XID fields by just echoing them.
* There is a remaining risk of malfunction
* when a phone submits values which defer from
* the default! */
LOGP(DLLC, LOGL_NOTICE,
"Echoing XID-Field: XID: type=%d, data_len=%d, data=%s\n",
xid_field->type, xid_field->data_len,
osmo_hexdump_nospc(xid_field->data,
xid_field->data_len));
xid_field_response =
gprs_llc_dup_xid_field
(lle->llme, xid_field);
llist_add(&xid_field_response->list,
xid_fields_response);
}
}
rc = gprs_llc_compile_xid(bytes_response,
bytes_response_maxlen,
xid_fields_response);
talloc_free(xid_fields_response);
talloc_free(xid_fields);
}
return rc;
}
/* Dispatch XID indications and responses comming from the Phone */
static void rx_llc_xid(struct gprs_llc_lle *lle,
struct gprs_llc_hdr_parsed *gph)
{
uint8_t response[1024];
int response_len;
/* FIXME: 8.5.3.3: check if XID is invalid */
if (gph->is_cmd) {
LOGP(DLLC, LOGL_NOTICE,
"Received XID indication from phone.\n");
struct msgb *resp;
uint8_t *xid;
resp = msgb_alloc_headroom(4096, 1024, "LLC_XID");
response_len =
gprs_llc_process_xid_ind(gph->data, gph->data_len,
response, sizeof(response),
lle);
xid = msgb_put(resp, response_len);
memcpy(xid, response, response_len);
gprs_llc_tx_xid(lle, resp, 0);
} else {
LOGP(DLLC, LOGL_NOTICE,
"Received XID confirmation from phone.\n");
gprs_llc_process_xid_conf(gph->data, gph->data_len, lle);
/* FIXME: if we had sent a XID reset, send
* LLGMM-RESET.conf to GMM */
}
}
/* Set of LL-XID negotiation (See also: TS 101 351, Section 7.2.2.4) */
int gprs_ll_xid_req(struct gprs_llc_lle *lle,
struct gprs_llc_xid_field *l3_xid_field)
{
/* Note: This functions is calle from gprs_sndcp.c */
uint8_t xid_bytes[1024];;
int xid_bytes_len;
uint8_t *xid;
struct msgb *msg;
/* Generate XID */
xid_bytes_len =
gprs_llc_generate_xid(xid_bytes, sizeof(xid_bytes),
l3_xid_field, lle->llme);
/* Only perform XID sending if the XID message contains something */
if (xid_bytes_len > 0) {
/* Transmit XID bytes */
msg = msgb_alloc_headroom(4096, 1024, "LLC_XID");
xid = msgb_put(msg, xid_bytes_len);
memcpy(xid, xid_bytes, xid_bytes_len);
LOGP(DLLC, LOGL_NOTICE, "Sending XID request to phone...\n");
gprs_llc_tx_xid(lle, msg, 1);
} else {
LOGP(DLLC, LOGL_ERROR,
"XID-Message generation failed, XID not sent!\n");
return -EINVAL;
}
return 0;
}
/* END XID RELATED */
/* Entry function from upper level (LLC), asking us to transmit a BSSGP PDU
* to a remote MS (identified by TLLI) at a BTS identified by its BVCI and NSEI */
@ -52,7 +330,7 @@ static int _bssgp_tx_dl_ud(struct msgb *msg, struct sgsn_mm_ctx *mmctx)
memset(&dup, 0, sizeof(dup));
/* before we have received some identity from the MS, we might
* not yet have a MMC context (e.g. XID negotiation of primarly
* LLC connection fro GMM sapi). */
* LLC connection from GMM sapi). */
if (mmctx) {
dup.imsi = mmctx->imsi;
dup.drx_parms = mmctx->drx_parms;
@ -252,6 +530,7 @@ static struct gprs_llc_llme *llme_alloc(uint32_t tlli)
static void llme_free(struct gprs_llc_llme *llme)
{
talloc_free(llme->xid);
llist_del(&llme->list);
talloc_free(llme);
}
@ -470,54 +749,6 @@ int gprs_llc_tx_ui(struct msgb *msg, uint8_t sapi, int command,
return _bssgp_tx_dl_ud(msg, mmctx);
}
/* According to 6.4.1.6 / Figure 11 */
static int msgb_put_xid_par(struct msgb *msg, uint8_t type, uint8_t length, uint8_t *data)
{
uint8_t header_len = 1;
uint8_t *cur;
/* type is a 5-bit field... */
if (type > 0x1f)
return -EINVAL;
if (length > 3)
header_len = 2;
cur = msgb_put(msg, length + header_len);
/* build the header without or with XL bit */
if (length <= 3) {
*cur++ = (type << 2) | (length & 3);
} else {
*cur++ = 0x80 | (type << 2) | (length >> 6);
*cur++ = (length << 2);
}
/* copy over the payload of the parameter*/
memcpy(cur, data, length);
return length + header_len;
}
static void rx_llc_xid(struct gprs_llc_lle *lle,
struct gprs_llc_hdr_parsed *gph)
{
/* FIXME: 8.5.3.3: check if XID is invalid */
if (gph->is_cmd) {
/* FIXME: implement XID negotiation using SNDCP */
struct msgb *resp;
uint8_t *xid;
resp = msgb_alloc_headroom(4096, 1024, "LLC_XID");
xid = msgb_put(resp, gph->data_len);
memcpy(xid, gph->data, gph->data_len);
gprs_llc_tx_xid(lle, resp, 0);
} else {
/* FIXME: if we had sent a XID reset, send
* LLGMM-RESET.conf to GMM */
/* FIXME: implement XID negotiation using SNDCP */
}
}
static int gprs_llc_hdr_rx(struct gprs_llc_hdr_parsed *gph,
struct gprs_llc_lle *lle)
{
@ -791,17 +1022,24 @@ int gprs_llgmm_reset(struct gprs_llc_llme *llme)
{
struct msgb *msg = msgb_alloc_headroom(4096, 1024, "LLC_XID");
struct gprs_llc_lle *lle = &llme->lle[1];
uint8_t xid_bytes[1024];
int xid_bytes_len;
uint8_t *xid;
LOGP(DLLC, LOGL_NOTICE, "LLGM Reset\n");
if (RAND_bytes((uint8_t *) &llme->iov_ui, 4) != 1) {
LOGP(DLLC, LOGL_NOTICE, "RAND_bytes failed for LLC XID reset, "
"falling back to rand()\n");
llme->iov_ui = rand();
}
/* First XID component must be RESET */
msgb_put_xid_par(msg, GPRS_LLC_XID_T_RESET, 0, NULL);
/* randomly select new IOV-UI */
msgb_put_xid_par(msg, GPRS_LLC_XID_T_IOV_UI, 4, (uint8_t *) &llme->iov_ui);
/* Generate XID message */
xid_bytes_len = gprs_llc_generate_xid_for_gmm_reset(xid_bytes,
sizeof(xid_bytes),llme->iov_ui,llme);
if(xid_bytes_len < 0)
return -EINVAL;
xid = msgb_put(msg, xid_bytes_len);
memcpy(xid, xid_bytes, xid_bytes_len);
/* Reset some of the LLC parameters. See GSM 04.64, 8.5.3.1 */
lle->vu_recv = 0;
@ -817,17 +1055,24 @@ int gprs_llgmm_reset_oldmsg(struct msgb* oldmsg, uint8_t sapi,
struct gprs_llc_llme *llme)
{
struct msgb *msg = msgb_alloc_headroom(4096, 1024, "LLC_XID");
uint8_t xid_bytes[1024];
int xid_bytes_len;
uint8_t *xid;
LOGP(DLLC, LOGL_NOTICE, "LLGM Reset\n");
if (RAND_bytes((uint8_t *) &llme->iov_ui, 4) != 1) {
LOGP(DLLC, LOGL_NOTICE, "RAND_bytes failed for LLC XID reset, "
"falling back to rand()\n");
llme->iov_ui = rand();
}
/* First XID component must be RESET */
msgb_put_xid_par(msg, GPRS_LLC_XID_T_RESET, 0, NULL);
/* randomly select new IOV-UI */
msgb_put_xid_par(msg, GPRS_LLC_XID_T_IOV_UI, 4, (uint8_t *) &llme->iov_ui);
/* Generate XID message */
xid_bytes_len = gprs_llc_generate_xid_for_gmm_reset(xid_bytes,
sizeof(xid_bytes),llme->iov_ui,llme);
if(xid_bytes_len < 0)
return -EINVAL;
xid = msgb_put(msg, xid_bytes_len);
memcpy(xid, xid_bytes, xid_bytes_len);
/* FIXME: Start T200, wait for XID response */

1
openbsc/tests/sgsn/Makefile.am
View File

@ -30,6 +30,7 @@ sgsn_test_LDADD = \
$(top_builddir)/src/gprs/gprs_gb_parse.o \
$(top_builddir)/src/gprs/oap.o \
$(top_builddir)/src/gprs/oap_messages.o \
$(top_builddir)/src/gprs/gprs_llc_xid.o \
$(top_builddir)/src/libcommon/libcommon.a \
$(LIBOSMOABIS_LIBS) \
$(LIBOSMOCORE_LIBS) \