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[X25]: Selective sub-address matching with call user data.

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From: Shaun Pereira <spereira@tusc.com.au>

This is the first (independent of the second) patch of two that I am
working on with x25 on linux (tested with xot on a cisco router).  Details
are as follows.

Current state of module:

A server using the current implementation (2.6.11.7) of the x25 module will
accept a call request/ incoming call packet at the listening x.25 address,
from all callers to that address, as long as NO call user data is present
in the packet header.

If the server needs to choose to accept a particular call request/ incoming
call packet arriving at its listening x25 address, then the kernel has to
allow a match of call user data present in the call request packet with its
own.  This is required when multiple servers listen at the same x25 address
and device interface.  The kernel currently matches ALL call user data, if
present.

Current Changes:

This patch is a follow up to the patch submitted previously by Andrew
Hendry, and allows the user to selectively control the number of octets of
call user data in the call request packet, that the kernel will match.  By
default no call user data is matched, even if call user data is present. 
To allow call user data matching, a cudmatchlength > 0 has to be passed
into the kernel after which the passed number of octets will be matched. 
Otherwise the kernel behavior is exactly as the original implementation.

This patch also ensures that as is normally the case, no call user data
will be present in the Call accepted / call connected packet sent back to
the caller 

Future Changes on next patch:

There are cases however when call user data may be present in the call
accepted packet.  According to the X.25 recommendation (ITU-T 10/96)
section 5.2.3.2 call user data may be present in the call accepted packet
provided the fast select facility is used.  My next patch will include this
fast select utility and the ability to send up to 128 octets call user data
in the call accepted packet provided the fast select facility is used.  I
am currently testing this, again with xot on linux and cisco.  

Signed-off-by: Shaun Pereira <spereira@tusc.com.au>

(With a fix from Alexey Dobriyan <adobriyan@gmail.com>)
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Shaun Pereira 2005-06-22 22:15:01 -07:00 committed by David S. Miller
parent 68d3187200
commit cb65d506c3
4 changed files with 59 additions and 45 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

10
include/linux/x25.h
View File

@ -4,6 +4,8 @@
* History
* mar/20/00 Daniela Squassoni Disabling/enabling of facilities
* negotiation.
* apr/02/05 Shaun Pereira Selective sub address matching with
* call user data
*/
#ifndef X25_KERNEL_H
@ -16,6 +18,7 @@
#define SIOCX25GCALLUSERDATA (SIOCPROTOPRIVATE + 4)
#define SIOCX25SCALLUSERDATA (SIOCPROTOPRIVATE + 5)
#define SIOCX25GCAUSEDIAG (SIOCPROTOPRIVATE + 6)
#define SIOCX25SCUDMATCHLEN (SIOCPROTOPRIVATE + 7)
/*
* Values for {get,set}sockopt.
@ -109,4 +112,11 @@ struct x25_causediag {
unsigned char diagnostic;
};
/*
* Further optional call user data match length selection
*/
struct x25_subaddr {
unsigned int cudmatchlength;
};
#endif

3
include/net/x25.h
View File

@ -134,7 +134,7 @@ struct x25_sock {
struct sock sk;
struct x25_address source_addr, dest_addr;
struct x25_neigh *neighbour;
unsigned int lci;
unsigned int lci, cudmatchlength;
unsigned char state, condition, qbitincl, intflag;
unsigned short vs, vr, va, vl;
unsigned long t2, t21, t22, t23;
@ -242,7 +242,6 @@ extern int x25_validate_nr(struct sock *, unsigned short);
extern void x25_write_internal(struct sock *, int);
extern int x25_decode(struct sock *, struct sk_buff *, int *, int *, int *, int *, int *);
extern void x25_disconnect(struct sock *, int, unsigned char, unsigned char);
extern int x25_check_calluserdata(struct x25_calluserdata *,struct x25_calluserdata *);
/* x25_timer.c */
extern void x25_start_heartbeat(struct sock *);

73
net/x25/af_x25.c
View File

@ -29,6 +29,8 @@
* 2000-11-14 Henner Eisen Closing datalink from NETDEV_GOING_DOWN
* 2002-10-06 Arnaldo C. Melo Get rid of cli/sti, move proc stuff to
* x25_proc.c, using seq_file
* 2005-04-02 Shaun Pereira Selective sub address matching
* with call user data
*/
#include <linux/config.h>
@ -219,7 +221,8 @@ static void x25_insert_socket(struct sock *sk)
* Note: if a listening socket has cud set it must only get calls
* with matching cud.
*/
static struct sock *x25_find_listener(struct x25_address *addr, struct x25_calluserdata *calluserdata)
static struct sock *x25_find_listener(struct x25_address *addr,
struct sk_buff *skb)
{
struct sock *s;
struct sock *next_best;
@ -230,22 +233,23 @@ static struct sock *x25_find_listener(struct x25_address *addr, struct x25_callu
sk_for_each(s, node, &x25_list)
if ((!strcmp(addr->x25_addr,
x25_sk(s)->source_addr.x25_addr) ||
!strcmp(addr->x25_addr,
null_x25_address.x25_addr)) &&
s->sk_state == TCP_LISTEN) {
x25_sk(s)->source_addr.x25_addr) ||
!strcmp(addr->x25_addr,
null_x25_address.x25_addr)) &&
s->sk_state == TCP_LISTEN) {
/*
* Found a listening socket, now check the incoming
* call user data vs this sockets call user data
*/
if (x25_check_calluserdata(&x25_sk(s)->calluserdata, calluserdata)) {
sock_hold(s);
goto found;
}
if (x25_sk(s)->calluserdata.cudlength == 0) {
if(skb->len > 0 && x25_sk(s)->cudmatchlength > 0) {
if((memcmp(x25_sk(s)->calluserdata.cuddata,
skb->data,
x25_sk(s)->cudmatchlength)) == 0) {
sock_hold(s);
goto found;
}
} else
next_best = s;
}
}
if (next_best) {
s = next_best;
@ -497,6 +501,7 @@ static int x25_create(struct socket *sock, int protocol)
x25->t23 = sysctl_x25_clear_request_timeout;
x25->t2 = sysctl_x25_ack_holdback_timeout;
x25->state = X25_STATE_0;
x25->cudmatchlength = 0;
x25->facilities.winsize_in = X25_DEFAULT_WINDOW_SIZE;
x25->facilities.winsize_out = X25_DEFAULT_WINDOW_SIZE;
@ -545,6 +550,7 @@ static struct sock *x25_make_new(struct sock *osk)
x25->t2 = ox25->t2;
x25->facilities = ox25->facilities;
x25->qbitincl = ox25->qbitincl;
x25->cudmatchlength = ox25->cudmatchlength;
x25_init_timers(sk);
out:
@ -822,7 +828,6 @@ int x25_rx_call_request(struct sk_buff *skb, struct x25_neigh *nb,
struct x25_sock *makex25;
struct x25_address source_addr, dest_addr;
struct x25_facilities facilities;
struct x25_calluserdata calluserdata;
int len, rc;
/*
@ -844,20 +849,11 @@ int x25_rx_call_request(struct sk_buff *skb, struct x25_neigh *nb,
len = skb->data[0] + 1;
skb_pull(skb,len);
/*
* Incoming Call User Data.
*/
if (skb->len >= 0) {
memcpy(calluserdata.cuddata, skb->data, skb->len);
calluserdata.cudlength = skb->len;
}
skb_push(skb,len);
/*
* Find a listener for the particular address/cud pair.
*/
sk = x25_find_listener(&source_addr,&calluserdata);
sk = x25_find_listener(&source_addr,skb);
skb_push(skb,len);
/*
* We can't accept the Call Request.
@ -900,12 +896,22 @@ int x25_rx_call_request(struct sk_buff *skb, struct x25_neigh *nb,
makex25->neighbour = nb;
makex25->facilities = facilities;
makex25->vc_facil_mask = x25_sk(sk)->vc_facil_mask;
makex25->calluserdata = calluserdata;
/* ensure no reverse facil on accept */
makex25->vc_facil_mask &= ~X25_MASK_REVERSE;
makex25->cudmatchlength = x25_sk(sk)->cudmatchlength;
x25_write_internal(make, X25_CALL_ACCEPTED);
makex25->state = X25_STATE_3;
/*
* Incoming Call User Data.
*/
if (skb->len >= 0) {
memcpy(makex25->calluserdata.cuddata, skb->data, skb->len);
makex25->calluserdata.cudlength = skb->len;
}
sk->sk_ack_backlog++;
x25_insert_socket(make);
@ -1325,6 +1331,23 @@ static int x25_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
break;
}
case SIOCX25SCUDMATCHLEN: {
struct x25_subaddr sub_addr;
rc = -EINVAL;
if(sk->sk_state != TCP_CLOSE)
break;
rc = -EFAULT;
if (copy_from_user(&sub_addr, argp,
sizeof(sub_addr)))
break;
rc = -EINVAL;
if(sub_addr.cudmatchlength > X25_MAX_CUD_LEN)
break;
x25->cudmatchlength = sub_addr.cudmatchlength;
rc = 0;
break;
}
default:
rc = dev_ioctl(cmd, argp);
break;

18
net/x25/x25_subr.c
View File

@ -354,21 +354,3 @@ void x25_check_rbuf(struct sock *sk)
}
}
/*
* Compare 2 calluserdata structures, used to find correct listening sockets
* when call user data is used.
*/
int x25_check_calluserdata(struct x25_calluserdata *ours, struct x25_calluserdata *theirs)
{
int i;
if (ours->cudlength != theirs->cudlength)
return 0;
for (i=0;i<ours->cudlength;i++) {
if (ours->cuddata[i] != theirs->cuddata[i]) {
return 0;
}
}
return 1;
}