From ebc3f64b864fc16a594c2e63bf55a55c7d42084b Mon Sep 17 00:00:00 2001 From: Shaun Pereira Date: Wed, 22 Jun 2005 22:16:17 -0700 Subject: [X25]: Fast select with no restriction on response This patch is a follow up to patch 1 regarding "Selective Sub Address matching with call user data". It allows use of the Fast-Select-Acceptance optional user facility for X.25. This patch just implements fast select with no restriction on response (NRR). What this means (according to ITU-T Recomendation 10/96 section 6.16) is that if in an incoming call packet, the relevant facility bits are set for fast-select-NRR, then the called DTE can issue a direct response to the incoming packet using a call-accepted packet that contains call-user-data. This patch allows such a response. The called DTE can also respond with a clear-request packet that contains call-user-data. However, this feature is currently not implemented by the patch. How is Fast Select Acceptance used? By default, the system does not allow fast select acceptance (as before). To enable a response to fast select acceptance, After a listen socket in created and bound as follows socket(AF_X25, SOCK_SEQPACKET, 0); bind(call_soc, (struct sockaddr *)&locl_addr, sizeof(locl_addr)); but before a listen system call is made, the following ioctl should be used. ioctl(call_soc,SIOCX25CALLACCPTAPPRV); Now the listen system call can be made listen(call_soc, 4); After this, an incoming-call packet will be accepted, but no call-accepted packet will be sent back until the following system call is made on the socket that accepts the call ioctl(vc_soc,SIOCX25SENDCALLACCPT); The network (or cisco xot router used for testing here) will allow the application server's call-user-data in the call-accepted packet, provided the call-request was made with Fast-select NRR. Signed-off-by: Shaun Pereira Signed-off-by: Andrew Morton Signed-off-by: David S. Miller --- net/x25/x25_subr.c | 23 ++++++++++++++++++----- 1 file changed, 18 insertions(+), 5 deletions(-) (limited to 'net/x25/x25_subr.c') diff --git a/net/x25/x25_subr.c b/net/x25/x25_subr.c index c349bbd61684..7fd872ad0c20 100644 --- a/net/x25/x25_subr.c +++ b/net/x25/x25_subr.c @@ -19,6 +19,8 @@ * mar/20/00 Daniela Squassoni Disabling/enabling of facilities * negotiation. * jun/24/01 Arnaldo C. Melo use skb_queue_purge, cleanups + * apr/04/15 Shaun Pereira Fast select with no + * restriction on response. */ #include @@ -127,8 +129,12 @@ void x25_write_internal(struct sock *sk, int frametype) len += 1 + X25_ADDR_LEN + X25_MAX_FAC_LEN + X25_MAX_CUD_LEN; break; - case X25_CALL_ACCEPTED: - len += 1 + X25_MAX_FAC_LEN + X25_MAX_CUD_LEN; + case X25_CALL_ACCEPTED: /* fast sel with no restr on resp */ + if(x25->facilities.reverse & 0x80) { + len += 1 + X25_MAX_FAC_LEN + X25_MAX_CUD_LEN; + } else { + len += 1 + X25_MAX_FAC_LEN; + } break; case X25_CLEAR_REQUEST: case X25_RESET_REQUEST: @@ -203,9 +209,16 @@ void x25_write_internal(struct sock *sk, int frametype) x25->vc_facil_mask); dptr = skb_put(skb, len); memcpy(dptr, facilities, len); - dptr = skb_put(skb, x25->calluserdata.cudlength); - memcpy(dptr, x25->calluserdata.cuddata, - x25->calluserdata.cudlength); + + /* fast select with no restriction on response + allows call user data. Userland must + ensure it is ours and not theirs */ + if(x25->facilities.reverse & 0x80) { + dptr = skb_put(skb, + x25->calluserdata.cudlength); + memcpy(dptr, x25->calluserdata.cuddata, + x25->calluserdata.cudlength); + } x25->calluserdata.cudlength = 0; break; -- cgit v1.2.3-59-g8ed1b