[PATCH] GPRS: Fix the byte ordering of the PDP context status IE

It seems that 24.008 Section 10.5.7.1 specifies the IE to be encoded in little endian... --- openbsc/src/gprs/gprs_gmm.c | 12 +++++++++++- 1 files changed, 11 insertions(+), 1 deletions(-) diff --git a/openbsc/src/gprs/gprs_gmm.c b/openbsc/src/gprs/gprs_gmm.c index 098e4c2..f83219f 100644 --- a/openbsc/src/gprs/gprs_gmm.c +++ b/openbsc/src/gprs/gprs_gmm.c @@ -870,6 +870,7 @@ static void process_ms_ctx_status(struct sgsn_mm_ctx *mmctx, uint16_t pdp_status) { struct sgsn_pdp_ctx *pdp, *pdp2; + uint16_t pdp_status_reordered; /* 24.008 4.7.5.1.3: If the PDP context status information element is * included in ROUTING AREA UPDATE REQUEST message, then the network * shall deactivate all those PDP contexts locally (without peer to @@ -877,8 +878,13 @@ static void process_ms_ctx_status(struct sgsn_mm_ctx *mmctx, * state PDP-INACTIVE on network side but are indicated by the MS as * being in state PDP-INACTIVE. */ + /* 24.008 10.5.7.1 indicates that the byte ordering is in fact + * little endian, i.e. the first octet contains NSAPI0..7 and + * the second payload octet NSAPI8..15 */ + pdp_status_reordered = (pdp_status & 0xff << 8) || (pdp_status >> 8); + llist_for_each_entry_safe(pdp, pdp2, &mmctx->pdp_list, list) { - if (!(pdp_status & (1 << pdp->nsapi))) { + if (!(pdp_status_reordered & (1 << pdp->nsapi))) { LOGP(DMM, LOGL_NOTICE, "Dropping PDP context for NSAPI=%u " "due to PDP CTX STATUS IE= 0x%04x\n", pdp->nsapi, pdp_status); @@ -977,6 +983,10 @@ static int gsm48_rx_gmm_ra_upd_req(struct sgsn_mm_ctx *mmctx, struct msgb *msg, if (TLVP_PRESENT(&tp, GSM48_IE_GMM_PDP_CTX_STATUS)) { uint16_t pdp_status = ntohs(*(uint16_t *) TLVP_VAL(&tp, GSM48_IE_GMM_PDP_CTX_STATUS)); + /* pdp_status is now in big endian, which is the wrong + * order. the wire encoding is little endian! We cannot + * simply drop the ntohs() above, as we migh be running + * on a big endian machine. */ process_ms_ctx_status(mmctx, pdp_status); } -- 1.7.5.4 --iq/fWD14IMVFWBCD--