[PATCH 2.6.19 1/2] X.25: Adds call forwarding to X.25
From: ahendry
Date: Wed Jan 03 2007 - 22:53:00 EST
Adds call forwarding to X.25, allowing it to operate like an X.25 router.
Useful if one needs to manipulate X.25 traffic with tools like tc.
This is an update/cleanup based off a patch submitted by Daniel Ferenci a few years ago.
Worked ok with Cisco XoT, linux X.25 back to back, and some old NTUs/PADs.
Signed-off-by: Andrew Hendry <andrew.hendry@xxxxxxxxx>
diff -uprN -X linux-2.6.19/Documentation/dontdiff linux-2.6.19-vanilla/include/net/x25.h linux-2.6.19/include/net/x25.h
--- linux-2.6.19-vanilla/include/net/x25.h 2006-12-31 22:31:06.000000000 +1100
+++ linux-2.6.19/include/net/x25.h 2007-01-01 17:06:13.000000000 +1100
@@ -161,6 +161,14 @@ struct x25_sock {
unsigned long vc_facil_mask; /* inc_call facilities mask */
};
+struct x25_forward {
+ struct list_head node;
+ unsigned int lci;
+ struct net_device *dev1;
+ struct net_device *dev2;
+ atomic_t refcnt;
+};
+
static inline struct x25_sock *x25_sk(const struct sock *sk)
{
return (struct x25_sock *)sk;
@@ -198,6 +206,12 @@ extern int x25_negotiate_facilities(stru
struct x25_dte_facilities *);
extern void x25_limit_facilities(struct x25_facilities *, struct x25_neigh *);
+/* x25_forward.c */
+extern void x25_clear_forwards(struct net_device *);
+extern struct x25_neigh *x25_find_forward(int, struct x25_neigh *);
+extern int x25_forward_call(struct x25_address *, struct x25_neigh *,
+ struct sk_buff *, int);
+
/* x25_in.c */
extern int x25_process_rx_frame(struct sock *, struct sk_buff *);
extern int x25_backlog_rcv(struct sock *, struct sk_buff *);
@@ -281,6 +295,8 @@ extern struct hlist_head x25_list;
extern rwlock_t x25_list_lock;
extern struct list_head x25_route_list;
extern rwlock_t x25_route_list_lock;
+extern struct list_head x25_forward_list;
+extern rwlock_t x25_forward_list_lock;
extern int x25_proc_init(void);
extern void x25_proc_exit(void);
diff -uprN -X linux-2.6.19/Documentation/dontdiff linux-2.6.19-vanilla/net/x25/af_x25.c linux-2.6.19/net/x25/af_x25.c
--- linux-2.6.19-vanilla/net/x25/af_x25.c 2006-12-31 22:31:07.000000000 +1100
+++ linux-2.6.19/net/x25/af_x25.c 2007-01-01 00:32:48.000000000 +1100
@@ -850,6 +850,9 @@ int x25_rx_call_request(struct sk_buff *
struct x25_dte_facilities dte_facilities;
int len, rc;
+ struct sk_buff *skbn;
+ skbn = skb_clone(skb, GFP_ATOMIC);
+
/*
* Remove the LCI and frame type.
*/
@@ -875,11 +878,23 @@ int x25_rx_call_request(struct sk_buff *
sk = x25_find_listener(&source_addr,skb);
skb_push(skb,len);
+ if (sk != NULL && sk_acceptq_is_full(sk)) {
+ goto out_sock_put;
+ }
+
/*
- * We can't accept the Call Request.
+ * We dont have any listeners for this incoming call.
+ * Try forwarding it.
*/
- if (sk == NULL || sk_acceptq_is_full(sk))
- goto out_clear_request;
+ if (sk == NULL) {
+ if (x25_forward_call(&dest_addr, nb, skbn, lci) == 0) {
+ /* Call was fowarded, dont process it any more */
+ return 0;
+ } else {
+ /* No listeners, can't forward, clear the call */
+ goto out_clear_request;
+ }
+ }
/*
* Try to reach a compromise on the requested facilities.
@@ -1600,6 +1615,9 @@ void x25_kill_by_neigh(struct x25_neigh
x25_disconnect(s, ENETUNREACH, 0, 0);
write_unlock_bh(&x25_list_lock);
+
+ /* Remove any related forwards */
+ x25_clear_forwards(nb->dev);
}
static int __init x25_init(void)
diff -uprN -X linux-2.6.19/Documentation/dontdiff linux-2.6.19-vanilla/net/x25/Makefile linux-2.6.19/net/x25/Makefile
--- linux-2.6.19-vanilla/net/x25/Makefile 2006-12-31 22:31:07.000000000 +1100
+++ linux-2.6.19/net/x25/Makefile 2006-12-31 23:25:38.000000000 +1100
@@ -6,5 +6,5 @@ obj-$(CONFIG_X25) += x25.o
x25-y := af_x25.o x25_dev.o x25_facilities.o x25_in.o \
x25_link.o x25_out.o x25_route.o x25_subr.o \
- x25_timer.o x25_proc.o
+ x25_timer.o x25_proc.o x25_forward.o
x25-$(CONFIG_SYSCTL) += sysctl_net_x25.o
diff -uprN -X linux-2.6.19/Documentation/dontdiff linux-2.6.19-vanilla/net/x25/x25_dev.c linux-2.6.19/net/x25/x25_dev.c
--- linux-2.6.19-vanilla/net/x25/x25_dev.c 2006-12-31 22:31:07.000000000 +1100
+++ linux-2.6.19/net/x25/x25_dev.c 2007-01-01 17:07:30.000000000 +1100
@@ -29,6 +29,7 @@ static int x25_receive_data(struct sk_bu
struct sock *sk;
unsigned short frametype;
unsigned int lci;
+ struct x25_neigh *to_neigh;
frametype = skb->data[2];
lci = ((skb->data[0] << 8) & 0xF00) + ((skb->data[1] << 0) & 0x0FF);
@@ -66,9 +67,19 @@ static int x25_receive_data(struct sk_bu
return x25_rx_call_request(skb, nb, lci);
/*
- * Its not a Call Request, nor is it a control frame.
- * Let caller throw it away.
+ * Its not a Call Request, nor is it a control frame.
+ * Can we forward it?
*/
+
+ if (( to_neigh = x25_find_forward(lci, nb)) != NULL) {
+ struct sk_buff *skbn = pskb_copy (skb, GFP_ATOMIC);
+ x25_transmit_link(skbn, to_neigh);
+ if (frametype == X25_CLEAR_CONFIRMATION) {
+ x25_clear_forwards(nb->dev);
+ }
+ return 1;
+ }
+
/*
x25_transmit_clear_request(nb, lci, 0x0D);
*/
diff -uprN -X linux-2.6.19/Documentation/dontdiff linux-2.6.19-vanilla/net/x25/x25_forward.c linux-2.6.19/net/x25/x25_forward.c
--- linux-2.6.19-vanilla/net/x25/x25_forward.c 1970-01-01 10:00:00.000000000 +1000
+++ linux-2.6.19/net/x25/x25_forward.c 2007-01-01 17:07:24.000000000 +1100
@@ -0,0 +1,115 @@
+/*
+ * 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
+ * 03-01-2007 Added forwarding for x.25 Andrew Hendry
+ */
+#include <linux/if_arp.h>
+#include <linux/init.h>
+#include <net/x25.h>
+
+struct list_head x25_forward_list = LIST_HEAD_INIT(x25_forward_list);
+DEFINE_RWLOCK(x25_forward_list_lock);
+
+int x25_forward_call(struct x25_address *dest_addr, struct x25_neigh *from,
+ struct sk_buff *skbn, int lci)
+{
+ struct x25_route *rt;
+ struct x25_neigh *neigh_new;
+ struct list_head *entry;
+ struct x25_forward *x25_frwd, *new_frwd;
+ short same_lci = 0;
+
+ if ((rt = x25_get_route(dest_addr)) != NULL) {
+
+ if ((neigh_new = x25_get_neigh(rt->dev)) == NULL) {
+ /* This shouldnt happen, if it occurs somehow
+ * do something sensible
+ */
+ return 1;
+ }
+
+ /* Avoid a loop. This is the normal exit path for a
+ * system with only one x.25 iface and default route
+ */
+ if (rt->dev == from->dev) {
+ return 1;
+ }
+
+ /* Remote end sending a call request on an already
+ * established LCI? It shouldnt happen, just in case..
+ */
+ read_lock_bh(&x25_forward_list_lock);
+ list_for_each(entry, &x25_forward_list) {
+ x25_frwd = list_entry(entry, struct x25_forward, node);
+ if (x25_frwd->lci == lci) {
+ printk(KERN_WARNING "X.25: call request for lci which is already registered!, transmitting but not registering new pair\n");
+ same_lci = 1;
+ }
+ }
+ read_unlock_bh(&x25_forward_list_lock);
+
+ /* Save the forwarding details for future traffic */
+ if (!same_lci){
+ if ((new_frwd = kmalloc(sizeof(struct x25_forward), GFP_ATOMIC)) == NULL)
+ return -ENOMEM;
+ new_frwd->lci = lci;
+ new_frwd->dev1 = rt->dev;
+ new_frwd->dev2 = from->dev;
+ write_lock_bh(&x25_forward_list_lock);
+ list_add(&new_frwd->node, &x25_forward_list);
+ write_unlock_bh(&x25_forward_list_lock);
+ }
+
+ /* Forward the call request */
+ x25_transmit_link(skbn, neigh_new);
+ return 0;
+ } else
+ return 1;
+}
+
+
+struct x25_neigh *x25_find_forward(int lci, struct x25_neigh *from) {
+
+ struct x25_forward *frwd;
+ struct list_head *entry;
+ struct net_device *peer = NULL;
+
+ read_lock_bh(&x25_forward_list_lock);
+ list_for_each(entry, &x25_forward_list) {
+ frwd = list_entry(entry, struct x25_forward, node);
+ if (frwd->lci == lci) {
+ /* The call is established, either side can send */
+ if (from->dev == frwd->dev1) {
+ peer = frwd->dev2;
+ } else {
+ peer = frwd->dev1;
+ }
+ break;
+ }
+ }
+ read_unlock_bh(&x25_forward_list_lock);
+ return x25_get_neigh(peer);
+}
+
+
+void x25_clear_forwards(struct net_device *dev)
+{
+ struct x25_forward *fwd;
+ struct list_head *entry, *tmp;
+
+ /* Remove any related forwards */
+ write_lock_bh(&x25_forward_list_lock);
+
+ list_for_each_safe(entry, tmp, &x25_forward_list) {
+ fwd = list_entry(entry, struct x25_forward, node);
+ if ((fwd->dev1 == dev) || (fwd->dev2 == dev)){
+ list_del(&fwd->node);
+ }
+ }
+ write_unlock_bh(&x25_forward_list_lock);
+}
diff -uprN -X linux-2.6.19/Documentation/dontdiff linux-2.6.19-vanilla/net/x25/x25_route.c linux-2.6.19/net/x25/x25_route.c
--- linux-2.6.19-vanilla/net/x25/x25_route.c 2006-12-31 22:31:07.000000000 +1100
+++ linux-2.6.19/net/x25/x25_route.c 2006-12-31 23:23:17.000000000 +1100
@@ -119,6 +119,9 @@ void x25_route_device_down(struct net_de
__x25_remove_route(rt);
}
write_unlock_bh(&x25_route_list_lock);
+
+ /* Remove any related forwarding */
+ x25_clear_forwards(dev);
}
/*
-
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