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[/] [test_project/] [trunk/] [linux_sd_driver/] [net/] [x25/] [x25_in.c] - Blame information for rev 62

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/*
 *      X.25 Packet Layer release 002
 *
 *      This is ALPHA test software. This code may break your machine,
 *      randomly fail to work with new releases, misbehave and/or generally
 *      screw up. It might even work.
 *
 *      This code REQUIRES 2.1.15 or higher
 *
 *      This module:
 *              This module is free software; you can redistribute it and/or
 *              modify it under the terms of the GNU General Public License
 *              as published by the Free Software Foundation; either version
 *              2 of the License, or (at your option) any later version.
 *
 *      History
 *      X.25 001        Jonathan Naylor   Started coding.
 *      X.25 002        Jonathan Naylor   Centralised disconnection code.
 *                                        New timer architecture.
 *      2000-03-20      Daniela Squassoni Disabling/enabling of facilities
 *                                        negotiation.
 *      2000-11-10      Henner Eisen      Check and reset for out-of-sequence
 *                                        i-frames.
 */
 
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/skbuff.h>
#include <net/sock.h>
#include <net/tcp_states.h>
#include <net/x25.h>
 
static int x25_queue_rx_frame(struct sock *sk, struct sk_buff *skb, int more)
{
        struct sk_buff *skbo, *skbn = skb;
        struct x25_sock *x25 = x25_sk(sk);
 
        if (more) {
                x25->fraglen += skb->len;
                skb_queue_tail(&x25->fragment_queue, skb);
                skb_set_owner_r(skb, sk);
                return 0;
        }
 
        if (!more && x25->fraglen > 0) { /* End of fragment */
                int len = x25->fraglen + skb->len;
 
                if ((skbn = alloc_skb(len, GFP_ATOMIC)) == NULL){
                        kfree_skb(skb);
                        return 1;
                }
 
                skb_queue_tail(&x25->fragment_queue, skb);
 
                skb_reset_transport_header(skbn);
 
                skbo = skb_dequeue(&x25->fragment_queue);
                skb_copy_from_linear_data(skbo, skb_put(skbn, skbo->len),
                                          skbo->len);
                kfree_skb(skbo);
 
                while ((skbo =
                        skb_dequeue(&x25->fragment_queue)) != NULL) {
                        skb_pull(skbo, (x25->neighbour->extended) ?
                                        X25_EXT_MIN_LEN : X25_STD_MIN_LEN);
                        skb_copy_from_linear_data(skbo,
                                                  skb_put(skbn, skbo->len),
                                                  skbo->len);
                        kfree_skb(skbo);
                }
 
                x25->fraglen = 0;
        }
 
        skb_set_owner_r(skbn, sk);
        skb_queue_tail(&sk->sk_receive_queue, skbn);
        if (!sock_flag(sk, SOCK_DEAD))
                sk->sk_data_ready(sk, skbn->len);
 
        return 0;
}
 
/*
 * State machine for state 1, Awaiting Call Accepted State.
 * The handling of the timer(s) is in file x25_timer.c.
 * Handling of state 0 and connection release is in af_x25.c.
 */
static int x25_state1_machine(struct sock *sk, struct sk_buff *skb, int frametype)
{
        struct x25_address source_addr, dest_addr;
 
        switch (frametype) {
                case X25_CALL_ACCEPTED: {
                        struct x25_sock *x25 = x25_sk(sk);
 
                        x25_stop_timer(sk);
                        x25->condition = 0x00;
                        x25->vs        = 0;
                        x25->va        = 0;
                        x25->vr        = 0;
                        x25->vl        = 0;
                        x25->state     = X25_STATE_3;
                        sk->sk_state   = TCP_ESTABLISHED;
                        /*
                         *      Parse the data in the frame.
                         */
                        skb_pull(skb, X25_STD_MIN_LEN);
                        skb_pull(skb, x25_addr_ntoa(skb->data, &source_addr, &dest_addr));
                        skb_pull(skb,
                                 x25_parse_facilities(skb, &x25->facilities,
                                                &x25->dte_facilities,
                                                &x25->vc_facil_mask));
                        /*
                         *      Copy any Call User Data.
                         */
                        if (skb->len >= 0) {
                                skb_copy_from_linear_data(skb,
                                              x25->calluserdata.cuddata,
                                              skb->len);
                                x25->calluserdata.cudlength = skb->len;
                        }
                        if (!sock_flag(sk, SOCK_DEAD))
                                sk->sk_state_change(sk);
                        break;
                }
                case X25_CLEAR_REQUEST:
                        x25_write_internal(sk, X25_CLEAR_CONFIRMATION);
                        x25_disconnect(sk, ECONNREFUSED, skb->data[3], skb->data[4]);
                        break;
 
                default:
                        break;
        }
 
        return 0;
}
 
/*
 * State machine for state 2, Awaiting Clear Confirmation State.
 * The handling of the timer(s) is in file x25_timer.c
 * Handling of state 0 and connection release is in af_x25.c.
 */
static int x25_state2_machine(struct sock *sk, struct sk_buff *skb, int frametype)
{
        switch (frametype) {
 
                case X25_CLEAR_REQUEST:
                        x25_write_internal(sk, X25_CLEAR_CONFIRMATION);
                        x25_disconnect(sk, 0, skb->data[3], skb->data[4]);
                        break;
 
                case X25_CLEAR_CONFIRMATION:
                        x25_disconnect(sk, 0, 0, 0);
                        break;
 
                default:
                        break;
        }
 
        return 0;
}
 
/*
 * State machine for state 3, Connected State.
 * The handling of the timer(s) is in file x25_timer.c
 * Handling of state 0 and connection release is in af_x25.c.
 */
static int x25_state3_machine(struct sock *sk, struct sk_buff *skb, int frametype, int ns, int nr, int q, int d, int m)
{
        int queued = 0;
        int modulus;
        struct x25_sock *x25 = x25_sk(sk);
 
        modulus = (x25->neighbour->extended) ? X25_EMODULUS : X25_SMODULUS;
 
        switch (frametype) {
 
                case X25_RESET_REQUEST:
                        x25_write_internal(sk, X25_RESET_CONFIRMATION);
                        x25_stop_timer(sk);
                        x25->condition = 0x00;
                        x25->vs        = 0;
                        x25->vr        = 0;
                        x25->va        = 0;
                        x25->vl        = 0;
                        x25_requeue_frames(sk);
                        break;
 
                case X25_CLEAR_REQUEST:
                        x25_write_internal(sk, X25_CLEAR_CONFIRMATION);
                        x25_disconnect(sk, 0, skb->data[3], skb->data[4]);
                        break;
 
                case X25_RR:
                case X25_RNR:
                        if (!x25_validate_nr(sk, nr)) {
                                x25_clear_queues(sk);
                                x25_write_internal(sk, X25_RESET_REQUEST);
                                x25_start_t22timer(sk);
                                x25->condition = 0x00;
                                x25->vs        = 0;
                                x25->vr        = 0;
                                x25->va        = 0;
                                x25->vl        = 0;
                                x25->state     = X25_STATE_4;
                        } else {
                                x25_frames_acked(sk, nr);
                                if (frametype == X25_RNR) {
                                        x25->condition |= X25_COND_PEER_RX_BUSY;
                                } else {
                                        x25->condition &= ~X25_COND_PEER_RX_BUSY;
                                }
                        }
                        break;
 
                case X25_DATA:  /* XXX */
                        x25->condition &= ~X25_COND_PEER_RX_BUSY;
                        if ((ns != x25->vr) || !x25_validate_nr(sk, nr)) {
                                x25_clear_queues(sk);
                                x25_write_internal(sk, X25_RESET_REQUEST);
                                x25_start_t22timer(sk);
                                x25->condition = 0x00;
                                x25->vs        = 0;
                                x25->vr        = 0;
                                x25->va        = 0;
                                x25->vl        = 0;
                                x25->state     = X25_STATE_4;
                                break;
                        }
                        x25_frames_acked(sk, nr);
                        if (ns == x25->vr) {
                                if (x25_queue_rx_frame(sk, skb, m) == 0) {
                                        x25->vr = (x25->vr + 1) % modulus;
                                        queued = 1;
                                } else {
                                        /* Should never happen */
                                        x25_clear_queues(sk);
                                        x25_write_internal(sk, X25_RESET_REQUEST);
                                        x25_start_t22timer(sk);
                                        x25->condition = 0x00;
                                        x25->vs        = 0;
                                        x25->vr        = 0;
                                        x25->va        = 0;
                                        x25->vl        = 0;
                                        x25->state     = X25_STATE_4;
                                        break;
                                }
                                if (atomic_read(&sk->sk_rmem_alloc) >
                                    (sk->sk_rcvbuf / 2))
                                        x25->condition |= X25_COND_OWN_RX_BUSY;
                        }
                        /*
                         *      If the window is full Ack it immediately, else
                         *      start the holdback timer.
                         */
                        if (((x25->vl + x25->facilities.winsize_in) % modulus) == x25->vr) {
                                x25->condition &= ~X25_COND_ACK_PENDING;
                                x25_stop_timer(sk);
                                x25_enquiry_response(sk);
                        } else {
                                x25->condition |= X25_COND_ACK_PENDING;
                                x25_start_t2timer(sk);
                        }
                        break;
 
                case X25_INTERRUPT_CONFIRMATION:
                        x25->intflag = 0;
                        break;
 
                case X25_INTERRUPT:
                        if (sock_flag(sk, SOCK_URGINLINE))
                                queued = !sock_queue_rcv_skb(sk, skb);
                        else {
                                skb_set_owner_r(skb, sk);
                                skb_queue_tail(&x25->interrupt_in_queue, skb);
                                queued = 1;
                        }
                        sk_send_sigurg(sk);
                        x25_write_internal(sk, X25_INTERRUPT_CONFIRMATION);
                        break;
 
                default:
                        printk(KERN_WARNING "x25: unknown %02X in state 3\n", frametype);
                        break;
        }
 
        return queued;
}
 
/*
 * State machine for state 4, Awaiting Reset Confirmation State.
 * The handling of the timer(s) is in file x25_timer.c
 * Handling of state 0 and connection release is in af_x25.c.
 */
static int x25_state4_machine(struct sock *sk, struct sk_buff *skb, int frametype)
{
        switch (frametype) {
 
                case X25_RESET_REQUEST:
                        x25_write_internal(sk, X25_RESET_CONFIRMATION);
                case X25_RESET_CONFIRMATION: {
                        struct x25_sock *x25 = x25_sk(sk);
 
                        x25_stop_timer(sk);
                        x25->condition = 0x00;
                        x25->va        = 0;
                        x25->vr        = 0;
                        x25->vs        = 0;
                        x25->vl        = 0;
                        x25->state     = X25_STATE_3;
                        x25_requeue_frames(sk);
                        break;
                }
                case X25_CLEAR_REQUEST:
                        x25_write_internal(sk, X25_CLEAR_CONFIRMATION);
                        x25_disconnect(sk, 0, skb->data[3], skb->data[4]);
                        break;
 
                default:
                        break;
        }
 
        return 0;
}
 
/* Higher level upcall for a LAPB frame */
int x25_process_rx_frame(struct sock *sk, struct sk_buff *skb)
{
        struct x25_sock *x25 = x25_sk(sk);
        int queued = 0, frametype, ns, nr, q, d, m;
 
        if (x25->state == X25_STATE_0)
                return 0;
 
        frametype = x25_decode(sk, skb, &ns, &nr, &q, &d, &m);
 
        switch (x25->state) {
                case X25_STATE_1:
                        queued = x25_state1_machine(sk, skb, frametype);
                        break;
                case X25_STATE_2:
                        queued = x25_state2_machine(sk, skb, frametype);
                        break;
                case X25_STATE_3:
                        queued = x25_state3_machine(sk, skb, frametype, ns, nr, q, d, m);
                        break;
                case X25_STATE_4:
                        queued = x25_state4_machine(sk, skb, frametype);
                        break;
        }
 
        x25_kick(sk);
 
        return queued;
}
 
int x25_backlog_rcv(struct sock *sk, struct sk_buff *skb)
{
        int queued = x25_process_rx_frame(sk, skb);
 
        if (!queued)
                kfree_skb(skb);
 
        return 0;
}

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[/] [test_project/] [trunk/] [linux_sd_driver/] [net/] [x25/] [x25_in.c] - Blame information for rev 62

Line No.	Rev	Author	Line
1	62	marcus.erl	`/*`
2			`* X.25 Packet Layer release 002`
3			`*`
4			`* This is ALPHA test software. This code may break your machine,`
5			`* randomly fail to work with new releases, misbehave and/or generally`
6			`* screw up. It might even work.`
7			`*`
8			`* This code REQUIRES 2.1.15 or higher`
9			`*`
10			`* This module:`
11			`* This module is free software; you can redistribute it and/or`
12			`* modify it under the terms of the GNU General Public License`
13			`* as published by the Free Software Foundation; either version`
14			`* 2 of the License, or (at your option) any later version.`
15			`*`
16			`* History`
17			`* X.25 001 Jonathan Naylor Started coding.`
18			`* X.25 002 Jonathan Naylor Centralised disconnection code.`
19			`* New timer architecture.`
20			`* 2000-03-20 Daniela Squassoni Disabling/enabling of facilities`
21			`* negotiation.`
22			`* 2000-11-10 Henner Eisen Check and reset for out-of-sequence`
23			`* i-frames.`
24			`*/`
25
26			`#include <linux/errno.h>`
27			`#include <linux/kernel.h>`
28			`#include <linux/string.h>`
29			`#include <linux/skbuff.h>`
30			`#include <net/sock.h>`
31			`#include <net/tcp_states.h>`
32			`#include <net/x25.h>`
33
34			`static int x25_queue_rx_frame(struct sock sk, struct sk_buff skb, int more)`
35			`{`
36			`struct sk_buff skbo, skbn = skb;`
37			`struct x25_sock *x25 = x25_sk(sk);`
38
39			`if (more) {`
40			`x25->fraglen += skb->len;`
41			`skb_queue_tail(&x25->fragment_queue, skb);`
42			`skb_set_owner_r(skb, sk);`
43			`return 0;`
44			`}`
45
46			`if (!more && x25->fraglen > 0) { /* End of fragment */`
47			`int len = x25->fraglen + skb->len;`
48
49			`if ((skbn = alloc_skb(len, GFP_ATOMIC)) == NULL){`
50			`kfree_skb(skb);`
51			`return 1;`
52			`}`
53
54			`skb_queue_tail(&x25->fragment_queue, skb);`
55
56			`skb_reset_transport_header(skbn);`
57
58			`skbo = skb_dequeue(&x25->fragment_queue);`
59			`skb_copy_from_linear_data(skbo, skb_put(skbn, skbo->len),`
60			`skbo->len);`
61			`kfree_skb(skbo);`
62
63			`while ((skbo =`
64			`skb_dequeue(&x25->fragment_queue)) != NULL) {`
65			`skb_pull(skbo, (x25->neighbour->extended) ?`
66			`X25_EXT_MIN_LEN : X25_STD_MIN_LEN);`
67			`skb_copy_from_linear_data(skbo,`
68			`skb_put(skbn, skbo->len),`
69			`skbo->len);`
70			`kfree_skb(skbo);`
71			`}`
72
73			`x25->fraglen = 0;`
74			`}`
75
76			`skb_set_owner_r(skbn, sk);`
77			`skb_queue_tail(&sk->sk_receive_queue, skbn);`
78			`if (!sock_flag(sk, SOCK_DEAD))`
79			`sk->sk_data_ready(sk, skbn->len);`
80
81			`return 0;`
82			`}`
83
84			`/*`
85			`* State machine for state 1, Awaiting Call Accepted State.`
86			`* The handling of the timer(s) is in file x25_timer.c.`
87			`* Handling of state 0 and connection release is in af_x25.c.`
88			`*/`
89			`static int x25_state1_machine(struct sock sk, struct sk_buff skb, int frametype)`
90			`{`
91			`struct x25_address source_addr, dest_addr;`
92
93			`switch (frametype) {`
94			`case X25_CALL_ACCEPTED: {`
95			`struct x25_sock *x25 = x25_sk(sk);`
96
97			`x25_stop_timer(sk);`
98			`x25->condition = 0x00;`
99			`x25->vs = 0;`
100			`x25->va = 0;`
101			`x25->vr = 0;`
102			`x25->vl = 0;`
103			`x25->state = X25_STATE_3;`
104			`sk->sk_state = TCP_ESTABLISHED;`
105			`/*`
106			`* Parse the data in the frame.`
107			`*/`
108			`skb_pull(skb, X25_STD_MIN_LEN);`
109			`skb_pull(skb, x25_addr_ntoa(skb->data, &source_addr, &dest_addr));`
110			`skb_pull(skb,`
111			`x25_parse_facilities(skb, &x25->facilities,`
112			`&x25->dte_facilities,`
113			`&x25->vc_facil_mask));`
114			`/*`
115			`* Copy any Call User Data.`
116			`*/`
117			`if (skb->len >= 0) {`
118			`skb_copy_from_linear_data(skb,`
119			`x25->calluserdata.cuddata,`
120			`skb->len);`
121			`x25->calluserdata.cudlength = skb->len;`
122			`}`
123			`if (!sock_flag(sk, SOCK_DEAD))`
124			`sk->sk_state_change(sk);`
125			`break;`
126			`}`
127			`case X25_CLEAR_REQUEST:`
128			`x25_write_internal(sk, X25_CLEAR_CONFIRMATION);`
129			`x25_disconnect(sk, ECONNREFUSED, skb->data[3], skb->data[4]);`
130			`break;`
131
132			`default:`
133			`break;`
134			`}`
135
136			`return 0;`
137			`}`
138
139			`/*`
140			`* State machine for state 2, Awaiting Clear Confirmation State.`
141			`* The handling of the timer(s) is in file x25_timer.c`
142			`* Handling of state 0 and connection release is in af_x25.c.`
143			`*/`
144			`static int x25_state2_machine(struct sock sk, struct sk_buff skb, int frametype)`
145			`{`
146			`switch (frametype) {`
147
148			`case X25_CLEAR_REQUEST:`
149			`x25_write_internal(sk, X25_CLEAR_CONFIRMATION);`
150			`x25_disconnect(sk, 0, skb->data[3], skb->data[4]);`
151			`break;`
152
153			`case X25_CLEAR_CONFIRMATION:`
154			`x25_disconnect(sk, 0, 0, 0);`
155			`break;`
156
157			`default:`
158			`break;`
159			`}`
160
161			`return 0;`
162			`}`
163
164			`/*`
165			`* State machine for state 3, Connected State.`
166			`* The handling of the timer(s) is in file x25_timer.c`
167			`* Handling of state 0 and connection release is in af_x25.c.`
168			`*/`
169			`static int x25_state3_machine(struct sock sk, struct sk_buff skb, int frametype, int ns, int nr, int q, int d, int m)`
170			`{`
171			`int queued = 0;`
172			`int modulus;`
173			`struct x25_sock *x25 = x25_sk(sk);`
174
175			`modulus = (x25->neighbour->extended) ? X25_EMODULUS : X25_SMODULUS;`
176
177			`switch (frametype) {`
178
179			`case X25_RESET_REQUEST:`
180			`x25_write_internal(sk, X25_RESET_CONFIRMATION);`
181			`x25_stop_timer(sk);`
182			`x25->condition = 0x00;`
183			`x25->vs = 0;`
184			`x25->vr = 0;`
185			`x25->va = 0;`
186			`x25->vl = 0;`
187			`x25_requeue_frames(sk);`
188			`break;`
189
190			`case X25_CLEAR_REQUEST:`
191			`x25_write_internal(sk, X25_CLEAR_CONFIRMATION);`
192			`x25_disconnect(sk, 0, skb->data[3], skb->data[4]);`
193			`break;`
194
195			`case X25_RR:`
196			`case X25_RNR:`
197			`if (!x25_validate_nr(sk, nr)) {`
198			`x25_clear_queues(sk);`
199			`x25_write_internal(sk, X25_RESET_REQUEST);`
200			`x25_start_t22timer(sk);`
201			`x25->condition = 0x00;`
202			`x25->vs = 0;`
203			`x25->vr = 0;`
204			`x25->va = 0;`
205			`x25->vl = 0;`
206			`x25->state = X25_STATE_4;`
207			`} else {`
208			`x25_frames_acked(sk, nr);`
209			`if (frametype == X25_RNR) {`
210			`x25->condition \|= X25_COND_PEER_RX_BUSY;`
211			`} else {`
212			`x25->condition &= ~X25_COND_PEER_RX_BUSY;`
213			`}`
214			`}`
215			`break;`
216
217			`case X25_DATA: /* XXX */`
218			`x25->condition &= ~X25_COND_PEER_RX_BUSY;`
219			`if ((ns != x25->vr) \|\| !x25_validate_nr(sk, nr)) {`
220			`x25_clear_queues(sk);`
221			`x25_write_internal(sk, X25_RESET_REQUEST);`
222			`x25_start_t22timer(sk);`
223			`x25->condition = 0x00;`
224			`x25->vs = 0;`
225			`x25->vr = 0;`
226			`x25->va = 0;`
227			`x25->vl = 0;`
228			`x25->state = X25_STATE_4;`
229			`break;`
230			`}`
231			`x25_frames_acked(sk, nr);`
232			`if (ns == x25->vr) {`
233			`if (x25_queue_rx_frame(sk, skb, m) == 0) {`
234			`x25->vr = (x25->vr + 1) % modulus;`
235			`queued = 1;`
236			`} else {`
237			`/* Should never happen */`
238			`x25_clear_queues(sk);`
239			`x25_write_internal(sk, X25_RESET_REQUEST);`
240			`x25_start_t22timer(sk);`
241			`x25->condition = 0x00;`
242			`x25->vs = 0;`
243			`x25->vr = 0;`
244			`x25->va = 0;`
245			`x25->vl = 0;`
246			`x25->state = X25_STATE_4;`
247			`break;`
248			`}`
249			`if (atomic_read(&sk->sk_rmem_alloc) >`
250			`(sk->sk_rcvbuf / 2))`
251			`x25->condition \|= X25_COND_OWN_RX_BUSY;`
252			`}`
253			`/*`
254			`* If the window is full Ack it immediately, else`
255			`* start the holdback timer.`
256			`*/`
257			`if (((x25->vl + x25->facilities.winsize_in) % modulus) == x25->vr) {`
258			`x25->condition &= ~X25_COND_ACK_PENDING;`
259			`x25_stop_timer(sk);`
260			`x25_enquiry_response(sk);`
261			`} else {`
262			`x25->condition \|= X25_COND_ACK_PENDING;`
263			`x25_start_t2timer(sk);`
264			`}`
265			`break;`
266
267			`case X25_INTERRUPT_CONFIRMATION:`
268			`x25->intflag = 0;`
269			`break;`
270
271			`case X25_INTERRUPT:`
272			`if (sock_flag(sk, SOCK_URGINLINE))`
273			`queued = !sock_queue_rcv_skb(sk, skb);`
274			`else {`
275			`skb_set_owner_r(skb, sk);`
276			`skb_queue_tail(&x25->interrupt_in_queue, skb);`
277			`queued = 1;`
278			`}`
279			`sk_send_sigurg(sk);`
280			`x25_write_internal(sk, X25_INTERRUPT_CONFIRMATION);`
281			`break;`
282
283			`default:`
284			`printk(KERN_WARNING "x25: unknown %02X in state 3\n", frametype);`
285			`break;`
286			`}`
287
288			`return queued;`
289			`}`
290
291			`/*`
292			`* State machine for state 4, Awaiting Reset Confirmation State.`
293			`* The handling of the timer(s) is in file x25_timer.c`
294			`* Handling of state 0 and connection release is in af_x25.c.`
295			`*/`
296			`static int x25_state4_machine(struct sock sk, struct sk_buff skb, int frametype)`
297			`{`
298			`switch (frametype) {`
299
300			`case X25_RESET_REQUEST:`
301			`x25_write_internal(sk, X25_RESET_CONFIRMATION);`
302			`case X25_RESET_CONFIRMATION: {`
303			`struct x25_sock *x25 = x25_sk(sk);`
304
305			`x25_stop_timer(sk);`
306			`x25->condition = 0x00;`
307			`x25->va = 0;`
308			`x25->vr = 0;`
309			`x25->vs = 0;`
310			`x25->vl = 0;`
311			`x25->state = X25_STATE_3;`
312			`x25_requeue_frames(sk);`
313			`break;`
314			`}`
315			`case X25_CLEAR_REQUEST:`
316			`x25_write_internal(sk, X25_CLEAR_CONFIRMATION);`
317			`x25_disconnect(sk, 0, skb->data[3], skb->data[4]);`
318			`break;`
319
320			`default:`
321			`break;`
322			`}`
323
324			`return 0;`
325			`}`
326
327			`/* Higher level upcall for a LAPB frame */`
328			`int x25_process_rx_frame(struct sock sk, struct sk_buff skb)`
329			`{`
330			`struct x25_sock *x25 = x25_sk(sk);`
331			`int queued = 0, frametype, ns, nr, q, d, m;`
332
333			`if (x25->state == X25_STATE_0)`
334			`return 0;`
335
336			`frametype = x25_decode(sk, skb, &ns, &nr, &q, &d, &m);`
337
338			`switch (x25->state) {`
339			`case X25_STATE_1:`
340			`queued = x25_state1_machine(sk, skb, frametype);`
341			`break;`
342			`case X25_STATE_2:`
343			`queued = x25_state2_machine(sk, skb, frametype);`
344			`break;`
345			`case X25_STATE_3:`
346			`queued = x25_state3_machine(sk, skb, frametype, ns, nr, q, d, m);`
347			`break;`
348			`case X25_STATE_4:`
349			`queued = x25_state4_machine(sk, skb, frametype);`
350			`break;`
351			`}`
352
353			`x25_kick(sk);`
354
355			`return queued;`
356			`}`
357
358			`int x25_backlog_rcv(struct sock sk, struct sk_buff skb)`
359			`{`
360			`int queued = x25_process_rx_frame(sk, skb);`
361
362			`if (!queued)`
363			`kfree_skb(skb);`
364
365			`return 0;`
366			`}`