From 4ac3aee711ae88280c35c996b75bfff1f2415e87 Mon Sep 17 00:00:00 2001 From: Philipp Date: Wed, 10 Aug 2016 12:24:09 +0200 Subject: 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 --- openbsc/include/openbsc/gprs_llc.h | 12 ++ openbsc/src/gprs/gprs_llc.c | 359 +++++++++++++++++++++++++++++++------ openbsc/tests/sgsn/Makefile.am | 1 + 3 files changed, 315 insertions(+), 57 deletions(-) diff --git a/openbsc/include/openbsc/gprs_llc.h b/openbsc/include/openbsc/gprs_llc.h index 0e497a080..c3b82b146 100644 --- a/openbsc/include/openbsc/gprs_llc.h +++ b/openbsc/include/openbsc/gprs_llc.h @@ -4,6 +4,7 @@ #include #include #include +#include /* 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); diff --git a/openbsc/src/gprs/gprs_llc.c b/openbsc/src/gprs/gprs_llc.c index c77fc0580..32920daef 100644 --- a/openbsc/src/gprs/gprs_llc.c +++ b/openbsc/src/gprs/gprs_llc.c @@ -39,8 +39,286 @@ #include #include #include +#include +#include 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 */ diff --git a/openbsc/tests/sgsn/Makefile.am b/openbsc/tests/sgsn/Makefile.am index b6036c75c..74af15991 100644 --- a/openbsc/tests/sgsn/Makefile.am +++ b/openbsc/tests/sgsn/Makefile.am @@ -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) \ -- cgit v1.2.3