@@ -84,6 +84,7 @@ struct bsc_connection {
/* do we know anything about this BSC? */
int authenticated;
+ uint8_t last_rand[16];
/* the fd we use to communicate */
struct osmo_wqueue write_queue;
@@ -188,9 +188,9 @@ static void send_id_ack(struct bsc_connection *bsc)
bsc_send_data(bsc, id_ack, sizeof(id_ack), IPAC_PROTO_IPACCESS);
}
-static void send_id_req(struct bsc_connection *bsc)
+static void send_id_req(struct bsc_nat *nat, struct bsc_connection *bsc)
{
- static const uint8_t id_req[] = {
+ static const uint8_t s_id_req[] = {
IPAC_MSGT_ID_GET,
0x01, IPAC_IDTAG_UNIT,
0x01, IPAC_IDTAG_MACADDR,
@@ -202,7 +202,41 @@ static void send_id_req(struct bsc_connection *bsc)
0x01, IPAC_IDTAG_SERNR,
};
+ int toread, rounds;
+ uint8_t *mrand, *randoff;
+ uint8_t id_req[sizeof(s_id_req) + (2+16)];
+ uint8_t *buf = &id_req[sizeof(s_id_req)];
+
+ /* copy the static data */
+ memcpy(id_req, s_id_req, sizeof(s_id_req));
+
+ /* put the RAND with length, tag, value */
+ buf = v_put(buf, 0x11);
+ buf = v_put(buf, 0x23);
+ mrand = bsc->last_rand;
+ randoff = mrand;
+ memset(randoff, 0, 16);
+
+ for (toread = 16, rounds = 0; rounds < 5 && toread > 0; ++rounds) {
+ int rc = read(nat->random_fd, randoff, toread);
+ if (rc <= 0)
+ goto failed_random;
+ toread -= rc;
+ randoff += rc;
+ }
+
+ if (toread != 0)
+ goto failed_random;
+ memcpy(buf, mrand, 16);
+ buf += 16;
+
bsc_send_data(bsc, id_req, sizeof(id_req), IPAC_PROTO_IPACCESS);
+ return;
+
+failed_random:
+ /* the timeout will trigger and close this connection */
+ LOGP(DNAT, LOGL_ERROR, "Failed to read from urandom.\n");
+ return;
}
static struct msgb *nat_create_rlsd(struct nat_sccp_connection *conn)
@@ -1362,7 +1396,7 @@ static int ipaccess_listen_bsc_cb(struct osmo_fd *bfd, unsigned int what)
bsc->last_id = 0;
send_id_ack(bsc);
- send_id_req(bsc);
+ send_id_req(nat, bsc);
send_mgcp_reset(bsc);
/*
From: Holger Hans Peter Freyther <holger@moiji-mobile.com> Generate 16 byte of random data to be used for A3A8 by the BSC in the response. We can't know which BSC it is at this point and I don't want to send another message once the token has been received so always send the data with an undefined code. The old BSCs don't parse the message and will happily ignore the RAND. /dev/urandom can give short reads on Linux so loop around it until the bytes have been read from the kernel. --- openbsc/include/openbsc/bsc_nat.h | 1 + openbsc/src/osmo-bsc_nat/bsc_nat.c | 40 +++++++++++++++++++++++++++++++++++--- 2 files changed, 38 insertions(+), 3 deletions(-)