gbproxy: Unify TLLI tracking
This patch unifies the TLLI tracking for all LLC messages. The TLLI state handling is moved into separate functions. Only Detach Accept messages are taken into account to release a TLLI, which is safe but not optimal. Sponsored-by: On-Waves ehf
This commit is contained in:
Jacob Erlbeck
Holger Hans Peter Freyther
parent
0cee7ad2bf
commit
2bdd253d54
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@ -1057,8 +1057,13 @@ static int gbprox_parse_dtap(uint8_t *data, size_t data_len,
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case GSM48_MT_GSM_ACT_PDP_REQ:
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return gbprox_parse_gsm_act_pdp_req(data, data_len, parse_ctx);
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case GSM48_MT_GMM_DETACH_ACK:
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case GSM48_MT_GMM_DETACH_REQ:
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/* TODO: Check power off if !to_bss, if yes invalidate */
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parse_ctx->llc_msg_name = "DETACH_REQ";
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break;
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case GSM48_MT_GMM_DETACH_ACK:
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parse_ctx->llc_msg_name = "DETACH_ACK";
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parse_ctx->invalidate_tlli = 1;
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break;
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@ -1082,6 +1087,11 @@ static int allow_message_patching(struct gbproxy_peer *peer, int msg_type)
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}
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}
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static void gbprox_update_state(struct gbproxy_peer *peer,
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struct gbproxy_parse_context *parse_ctx);
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static void gbprox_update_state_after(struct gbproxy_peer *peer,
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struct gbproxy_parse_context *parse_ctx);
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static void gbprox_patch_llc(struct msgb *msg, uint8_t *llc, size_t llc_len,
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struct gbproxy_peer *peer, int *len_change,
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struct gbproxy_parse_context *parse_ctx) __attribute__((nonnull));
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@ -1095,9 +1105,6 @@ static void gbprox_patch_llc(struct msgb *msg, uint8_t *llc, size_t llc_len,
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uint8_t *data;
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size_t data_len;
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int fcs;
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const char *err_info = NULL;
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int err_ctr = -1;
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uint32_t tlli = parse_ctx->tlli;
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int have_patched = 0;
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/* parse LLC */
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@ -1118,12 +1125,8 @@ static void gbprox_patch_llc(struct msgb *msg, uint8_t *llc, size_t llc_len,
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if (ghp.sapi != GPRS_SAPI_GMM)
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return;
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if (peer->cfg->core_apn && parse_ctx->to_bss && tlli && parse_ctx->imsi)
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gbprox_register_tlli(peer, tlli,
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parse_ctx->imsi, parse_ctx->imsi_len);
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if (ghp.cmd != GPRS_LLC_UI)
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return;
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goto update_tlli_mapping;
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if (ghp.is_encrypted) {
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if (patching_is_required(peer, GBPROX_PATCH_LLC_ATTACH)) {
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@ -1132,12 +1135,12 @@ static void gbprox_patch_llc(struct msgb *msg, uint8_t *llc, size_t llc_len,
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* so we possibly fail to patch the LLC part of the
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* message. */
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err_info = "GMM message is encrypted";
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err_ctr = GBPROX_PEER_CTR_PATCH_CRYPT_ERR;
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goto patch_error;
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rate_ctr_inc(&peer->ctrg->ctr[GBPROX_PEER_CTR_PATCH_CRYPT_ERR]);
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LOGP(DGPRS, LOGL_ERROR,
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"Failed to patch BSSGP/GMM message as requested: "
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"GMM message is encrypted\n");
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}
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return;
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goto update_tlli_mapping;
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}
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/* fix DTAP GMM/GSM */
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@ -1147,87 +1150,129 @@ static void gbprox_patch_llc(struct msgb *msg, uint8_t *llc, size_t llc_len,
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parse_ctx->llc_hdr_parsed = &ghp;
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rc = gbprox_parse_dtap(data, data_len, parse_ctx);
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if (!rc)
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return;
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switch (parse_ctx->g48_hdr->msg_type) {
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case GSM48_MT_GMM_ATTACH_REQ:
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rate_ctr_inc(&peer->ctrg->ctr[GBPROX_PEER_CTR_ATTACH_REQS]);
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break;
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update_tlli_mapping:
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case GSM48_MT_GMM_ATTACH_REJ:
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rate_ctr_inc(&peer->ctrg->ctr[GBPROX_PEER_CTR_ATTACH_REJS]);
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break;
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gbprox_update_state(peer, parse_ctx);
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default:
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break;
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if (parse_ctx->g48_hdr &&
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allow_message_patching(peer, parse_ctx->g48_hdr->msg_type)) {
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if (parse_ctx->raid_enc) {
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gbprox_patch_raid(parse_ctx->raid_enc, peer,
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parse_ctx->to_bss,
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parse_ctx->llc_msg_name);
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have_patched = 1;
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}
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if (parse_ctx->apn_ie &&
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peer->cfg->core_apn &&
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!parse_ctx->to_bss &&
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gbprox_check_tlli(peer, parse_ctx->tlli)) {
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size_t new_len;
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gbprox_patch_apn_ie(msg,
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parse_ctx->apn_ie,
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parse_ctx->apn_ie_len, peer,
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&new_len, parse_ctx->llc_msg_name);
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*len_change += (int)new_len - (int)parse_ctx->apn_ie_len;
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have_patched = 1;
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}
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if (have_patched) {
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llc_len += *len_change;
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ghp.crc_length += *len_change;
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/* Fix FCS */
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fcs = gprs_llc_fcs(llc, ghp.crc_length);
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LOGP(DLLC, LOGL_DEBUG,
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"Updated LLC message, CRC: %06x -> %06x\n",
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ghp.fcs, fcs);
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llc[llc_len - 3] = fcs & 0xff;
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llc[llc_len - 2] = (fcs >> 8) & 0xff;
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llc[llc_len - 1] = (fcs >> 16) & 0xff;
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}
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}
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if (parse_ctx->ptmsi_enc &&
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peer->cfg->core_apn && parse_ctx->to_bss && parse_ctx->imsi) {
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gbprox_update_state_after(peer, parse_ctx);
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return;
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}
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static void gbprox_update_state(struct gbproxy_peer *peer,
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struct gbproxy_parse_context *parse_ctx)
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{
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const char *msg_name = "LLC";
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if (parse_ctx->llc_msg_name)
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msg_name = parse_ctx->llc_msg_name;
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if (parse_ctx->g48_hdr) {
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switch (parse_ctx->g48_hdr->msg_type) {
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case GSM48_MT_GMM_ATTACH_REQ:
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rate_ctr_inc(&peer->ctrg->ctr[GBPROX_PEER_CTR_ATTACH_REQS]);
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break;
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case GSM48_MT_GMM_ATTACH_REJ:
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rate_ctr_inc(&peer->ctrg->ctr[GBPROX_PEER_CTR_ATTACH_REJS]);
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break;
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default:
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break;
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}
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}
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if (parse_ctx->tlli) {
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LOGP(DGPRS, LOGL_DEBUG, "%s: Got TLLI %08x\n",
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msg_name, parse_ctx->tlli);
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}
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if (parse_ctx->ptmsi_enc) {
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uint32_t new_ptmsi = GSM_RESERVED_TMSI;
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int ok;
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ok = parse_mi_tmsi(parse_ctx->ptmsi_enc, GSM48_TMSI_LEN,
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&new_ptmsi);
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LOGP(DGPRS, LOGL_DEBUG, "%s: Got new PTMSI %08x%s\n",
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msg_name, new_ptmsi, ok ? "" : " (parse error)");
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}
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if (parse_ctx->imsi) {
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char mi_buf[200];
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mi_buf[0] = '\0';
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gsm48_mi_to_string(mi_buf, sizeof(mi_buf),
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parse_ctx->imsi, parse_ctx->imsi_len);
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LOGP(DGPRS, LOGL_DEBUG, "%s: Got IMSI %s\n",
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msg_name, mi_buf);
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}
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if (parse_ctx->ptmsi_enc && parse_ctx->to_bss && parse_ctx->imsi) {
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/* A new TLLI (PTMSI) has been signaled in the message */
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uint32_t new_ptmsi;
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if (!parse_mi_tmsi(parse_ctx->ptmsi_enc, GSM48_TMSI_LEN,
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&new_ptmsi)) {
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err_info = "Failed to parse new P-TMSI";
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err_ctr = GBPROX_PEER_CTR_PATCH_ERR;
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goto patch_error;
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LOGP(DGPRS, LOGL_ERROR,
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"Failed to parse new TLLI/PTMSI (current is %08x)\n",
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parse_ctx->tlli);
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return;
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}
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LOGP(DGPRS, LOGL_INFO,
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"Got new TLLI/PTMSI %08x (current is %08x)\n",
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new_ptmsi, tlli);
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new_ptmsi, parse_ctx->tlli);
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gbprox_register_tlli(peer, new_ptmsi,
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parse_ctx->imsi, parse_ctx->imsi_len);
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} else if (parse_ctx->invalidate_tlli) {
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} else if (parse_ctx->tlli && parse_ctx->imsi) {
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gbprox_register_tlli(peer, parse_ctx->tlli,
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parse_ctx->imsi, parse_ctx->imsi_len);
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}
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return;
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}
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static void gbprox_update_state_after(struct gbproxy_peer *peer,
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struct gbproxy_parse_context *parse_ctx)
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{
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if (parse_ctx->invalidate_tlli)
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gbprox_unregister_tlli(peer, parse_ctx->tlli);
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}
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if (!allow_message_patching(peer, parse_ctx->g48_hdr->msg_type))
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return;
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if (parse_ctx->raid_enc) {
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gbprox_patch_raid(parse_ctx->raid_enc, peer, parse_ctx->to_bss,
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parse_ctx->llc_msg_name);
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have_patched = 1;
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}
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if (parse_ctx->apn_ie &&
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peer->cfg->core_apn &&
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!parse_ctx->to_bss &&
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gbprox_check_tlli(peer, parse_ctx->tlli)) {
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size_t new_len;
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gbprox_patch_apn_ie(msg,
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parse_ctx->apn_ie, parse_ctx->apn_ie_len,
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peer, &new_len, parse_ctx->llc_msg_name);
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*len_change += (int)new_len - (int)parse_ctx->apn_ie_len;
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have_patched = 1;
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}
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if (have_patched) {
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llc_len += *len_change;
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ghp.crc_length += *len_change;
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/* Fix FCS */
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fcs = gprs_llc_fcs(llc, ghp.crc_length);
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LOGP(DLLC, LOGL_DEBUG, "Updated LLC message, CRC: %06x -> %06x\n",
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ghp.fcs, fcs);
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llc[llc_len - 3] = fcs & 0xff;
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llc[llc_len - 2] = (fcs >> 8) & 0xff;
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llc[llc_len - 1] = (fcs >> 16) & 0xff;
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}
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return;
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patch_error:
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OSMO_ASSERT(err_ctr >= 0);
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rate_ctr_inc(&peer->ctrg->ctr[err_ctr]);
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LOGP(DGPRS, LOGL_ERROR,
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"Failed to patch BSSGP/GMM message as requested: %s.\n", err_info);
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return;
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}
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/* patch BSSGP message to use core_mcc/mnc on the SGSN side */
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