fixeria has uploaded this change for review. ( https://gerrit.osmocom.org/c/osmocom-bb/+/30627 )

Change subject: trxcon: preserve A5 params during [P]DCH-to-DCH transition ......................................................................

trxcon: preserve A5 params during [P]DCH-to-DCH transition

This is not really needed because layer23 apps do send another another L1CTL_CRYPTO_REQ message for the new DCH. I wrote this patch before I figured this out, but we may want to offload the task of preserving the A5 params to the L1 some day...

Change-Id: I822a27a1bacc21dae7a3e31166a7609c7e1faeff --- M src/host/trxcon/include/osmocom/bb/trxcon/trxcon.h M src/host/trxcon/src/trxcon_fsm.c 2 files changed, 24 insertions(+), 0 deletions(-)

git pull ssh://gerrit.osmocom.org:29418/osmocom-bb refs/changes/27/30627/1

diff --git a/src/host/trxcon/include/osmocom/bb/trxcon/trxcon.h b/src/host/trxcon/include/osmocom/bb/trxcon/trxcon.h index 9148771..103a047 100644 --- a/src/host/trxcon/include/osmocom/bb/trxcon/trxcon.h +++ b/src/host/trxcon/include/osmocom/bb/trxcon/trxcon.h @@ -31,6 +31,11 @@ uint16_t band_arfcn; uint8_t tx_power; int8_t ta; + + /* A5 encryption state */ + uint8_t a5_algo; + uint8_t a5_key_len; + uint8_t a5_key[128 / 8]; /* MAX_A5_KEY_LEN */ } l1p; };

diff --git a/src/host/trxcon/src/trxcon_fsm.c b/src/host/trxcon/src/trxcon_fsm.c index b575fd0..dbab84a 100644 --- a/src/host/trxcon/src/trxcon_fsm.c +++ b/src/host/trxcon/src/trxcon_fsm.c @@ -64,6 +64,11 @@ trxcon->l1p.tx_power = 0; trxcon->l1p.ta = 0;

+ /* Reset the A5 state */ + trxcon->l1p.a5_algo = 0; + trxcon->l1p.a5_key_len = 0; + memset(&trxcon->l1p.a5_key[0], 0x00, sizeof(trxcon->l1p.a5_key)); + phycmd.type = TRXCON_PHYIF_CMDT_RESET; trxcon_phyif_handle_cmd(trxcon->phyif, &phycmd); break; @@ -359,6 +364,15 @@ return; }

+ /* Reapply A5 ciphering parameters (if needed) */ + if (config != GSM_PCHAN_PDCH && trxcon->l1p.a5_algo) { + rc = l1sched_start_ciphering(ts, trxcon->l1p.a5_algo, + &trxcon->l1p.a5_key[0], + trxcon->l1p.a5_key_len); + if (rc != 0) + LOGPFSML(fi, LOGL_ERROR, "Failed to configure ciphering\n"); + } + if (config == GSM_PCHAN_PDCH) osmo_fsm_inst_state_chg(fi, TRXCON_ST_PACKET_DATA, 0, 0); else @@ -492,6 +506,11 @@ LOGPFSML(fi, LOGL_ERROR, "Failed to configure ciphering\n"); return; } + + trxcon->l1p.a5_algo = req->a5_algo; + trxcon->l1p.a5_key_len = req->key_len; + OSMO_ASSERT(req->key_len <= sizeof(trxcon->l1p.a5_key)); + memcpy(&trxcon->l1p.a5_key[0], req->key, req->key_len); break; } case TRXCON_EV_TX_DATA_REQ: