lkml.org 
[lkml]   [2003]   [Feb]   [10]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patches in this message
/
Date
From
Subject[RFC]: CONFIG_IPPP_FILTER
Hi,
this patch adds ippp filters to isdn similar to ppp filters. Also
included is the required patch for
ipppd. To compile ipppd add -DIPPP_FILTER to CFLAGS and -lpcap to LIBS.
Comments and suggestions are welcome.

Regards,
Patrick

diff -urN linux-2.4.20-clean/Documentation/Configure.help linux-2.4.20_ippp-filter/Documentation/Configure.help
--- linux-2.4.20-clean/Documentation/Configure.help 2002-11-29 00:53:08.000000000 +0100
+++ linux-2.4.20_ippp-filter/Documentation/Configure.help 2003-02-10 23:27:05.000000000 +0100
@@ -20432,6 +20432,17 @@
feature. See <file:Documentation/isdn/README.syncppp> and
<file:Documentation/isdn/syncPPP.FAQ> for more information.

+PPP filtering for ISDN
+CONFIG_IPPP_FILTER
+ Say Y here if you want to be able to filter the packets passing over
+ IPPP interfaces. This allows you to control which packets count as
+ activity (i.e. which packets will reset the idle timer or bring up
+ a demand-dialled link) and which packets are to be dropped entirely.
+ You need to say Y here if you wish to use the pass-filter and
+ active-filter options to ipppd.
+
+ If unsure, say N.
+
Support generic MP (RFC 1717)
CONFIG_ISDN_MPP
With synchronous PPP enabled, it is possible to increase throughput
diff -urN linux-2.4.20-clean/drivers/isdn/Config.in linux-2.4.20_ippp-filter/drivers/isdn/Config.in
--- linux-2.4.20-clean/drivers/isdn/Config.in 2002-11-29 00:53:13.000000000 +0100
+++ linux-2.4.20_ippp-filter/drivers/isdn/Config.in 2003-02-10 23:27:05.000000000 +0100
@@ -8,6 +8,7 @@
if [ "$CONFIG_INET" != "n" ]; then
bool ' Support synchronous PPP' CONFIG_ISDN_PPP
if [ "$CONFIG_ISDN_PPP" != "n" ]; then
+ bool ' PPP filtering for ISDN' CONFIG_IPPP_FILTER $CONFIG_FILTER
bool ' Use VJ-compression with synchronous PPP' CONFIG_ISDN_PPP_VJ
bool ' Support generic MP (RFC 1717)' CONFIG_ISDN_MPP
dep_tristate ' Support BSD compression' CONFIG_ISDN_PPP_BSDCOMP $CONFIG_ISDN
diff -urN linux-2.4.20-clean/drivers/isdn/isdn_net.c linux-2.4.20_ippp-filter/drivers/isdn/isdn_net.c
--- linux-2.4.20-clean/drivers/isdn/isdn_net.c 2002-11-29 00:53:13.000000000 +0100
+++ linux-2.4.20_ippp-filter/drivers/isdn/isdn_net.c 2003-02-10 23:27:05.000000000 +0100
@@ -1296,6 +1296,16 @@
restore_flags(flags);
return 0; /* STN (skb to nirvana) ;) */
}
+#ifdef CONFIG_IPPP_FILTER
+ if (isdn_ppp_autodial_filter(skb, lp)) {
+ isdn_ppp_free(lp);
+ isdn_net_unbind_channel(lp);
+ restore_flags(flags);
+ isdn_net_unreachable(ndev, skb, "dial rejected: packet filtered");
+ dev_kfree_skb(skb);
+ return 0;
+ }
+#endif
restore_flags(flags);
isdn_net_dial(); /* Initiate dialing */
netif_stop_queue(ndev);
@@ -1793,9 +1803,6 @@
{
isdn_net_local *lp = (isdn_net_local *) ndev->priv;
isdn_net_local *olp = lp; /* original 'lp' */
-#ifdef CONFIG_ISDN_PPP
- int proto = PPP_PROTOCOL(skb->data);
-#endif
#ifdef CONFIG_ISDN_X25
struct concap_proto *cprot = lp -> netdev -> cprot;
#endif
@@ -1855,14 +1862,7 @@
break;
#ifdef CONFIG_ISDN_PPP
case ISDN_NET_ENCAP_SYNCPPP:
- /*
- * If encapsulation is syncppp, don't reset
- * huptimer on LCP packets.
- */
- if (proto != PPP_LCP) {
- olp->huptimer = 0;
- lp->huptimer = 0;
- }
+ /* huptimer is done in isdn_ppp_push_higher */
isdn_ppp_receive(lp->netdev, olp, skb);
return;
#endif
diff -urN linux-2.4.20-clean/drivers/isdn/isdn_ppp.c linux-2.4.20_ippp-filter/drivers/isdn/isdn_ppp.c
--- linux-2.4.20-clean/drivers/isdn/isdn_ppp.c 2002-11-29 00:53:13.000000000 +0100
+++ linux-2.4.20_ippp-filter/drivers/isdn/isdn_ppp.c 2003-02-10 23:27:05.000000000 +0100
@@ -13,6 +13,9 @@
#include <linux/isdn.h>
#include <linux/poll.h>
#include <linux/ppp-comp.h>
+#ifdef CONFIG_IPPP_FILTER
+#include <linux/filter.h>
+#endif

#include "isdn_common.h"
#include "isdn_ppp.h"
@@ -324,7 +327,10 @@
*/
is->slcomp = slhc_init(16, 16); /* not necessary for 2. link in bundle */
#endif
-
+#ifdef CONFIG_IPPP_FILTER
+ is->pass_filter.filter = NULL;
+ is->active_filter.filter = NULL;
+#endif
is->state = IPPP_OPEN;

return 0;
@@ -379,6 +385,16 @@
slhc_free(is->slcomp);
is->slcomp = NULL;
#endif
+#ifdef CONFIG_IPPP_FILTER
+ if (is->pass_filter.filter) {
+ kfree(is->pass_filter.filter);
+ is->pass_filter.filter = NULL;
+ }
+ if (is->active_filter.filter) {
+ kfree(is->active_filter.filter);
+ is->active_filter.filter = NULL;
+ }
+#endif

/* TODO: if this was the previous master: link the the stuff to the new master */
if(is->comp_stat)
@@ -588,6 +604,37 @@
}
return set_arg((void *)arg,&pci,sizeof(struct pppcallinfo));
}
+#ifdef CONFIG_IPPP_FILTER
+ case PPPIOCSPASS:
+ case PPPIOCSACTIVE:
+ {
+ struct sock_fprog uprog, *filtp;
+ struct sock_filter *code = NULL;
+ int len, err;
+
+ if (copy_from_user(&uprog, (void *) arg, sizeof(uprog)))
+ return -EFAULT;
+ if (uprog.len > 0 && uprog.len < 65536) {
+ len = uprog.len * sizeof(struct sock_filter);
+ code = kmalloc(len, GFP_KERNEL);
+ if (code == NULL)
+ return -ENOMEM;
+ if (copy_from_user(code, uprog.filter, len))
+ return -EFAULT;
+ err = sk_chk_filter(code, uprog.len);
+ if (err) {
+ kfree(code);
+ return err;
+ }
+ }
+ filtp = (cmd == PPPIOCSPASS) ? &is->pass_filter : &is->active_filter;
+ if (filtp->filter)
+ kfree(filtp->filter);
+ filtp->filter = code;
+ filtp->len = uprog.len;
+ break;
+ }
+#endif /* CONFIG_IPPP_FILTER */
default:
break;
}
@@ -977,6 +1024,7 @@
{
struct net_device *dev = &net_dev->dev;
struct ippp_struct *is, *mis;
+ isdn_net_local *mlp = NULL;
int slot;

slot = lp->ppp_slot;
@@ -988,7 +1036,8 @@
is = ippp_table[slot];

if (lp->master) { // FIXME?
- slot = ((isdn_net_local *) (lp->master->priv))->ppp_slot;
+ mlp = (isdn_net_local *) lp->master->priv;
+ slot = mlp->ppp_slot;
if (slot < 0 || slot > ISDN_MAX_CHANNELS) {
printk(KERN_ERR "isdn_ppp_push_higher: master->ppp_slot(%d)\n",
lp->ppp_slot);
@@ -1082,9 +1131,36 @@
return;
}

- /* Reset hangup-timer */
- lp->huptimer = 0;
-
+#ifdef CONFIG_IPPP_FILTER
+ /* check if the packet passes the pass and active filters
+ * the filter instructions are constructed assuming
+ * a four-byte PPP header on each packet (which is still present) */
+ skb_push(skb, 4);
+ skb->data[0] = 0; /* indicate inbound */
+
+ if (is->pass_filter.filter
+ && sk_run_filter(skb, is->pass_filter.filter,
+ is->pass_filter.len) == 0) {
+ if (is->debug & 0x2)
+ printk(KERN_DEBUG "IPPP: inbound frame filtered.\n");
+ kfree_skb(skb);
+ return;
+ }
+ if (!(is->active_filter.filter
+ && sk_run_filter(skb, is->active_filter.filter,
+ is->active_filter.len) == 0)) {
+ if (is->debug & 0x2)
+ printk(KERN_DEBUG "IPPP: link-active filter: reseting huptimer.\n");
+ lp->huptimer = 0;
+ if (mlp)
+ mlp->huptimer = 0;
+ }
+ skb_pull(skb, 4);
+#else /* CONFIG_IPPP_FILTER */
+ lp->huptimer = 0;
+ if (mlp)
+ mlp->huptimer = 0;
+#endif /* CONFIG_IPPP_FILTER */
skb->dev = dev;
skb->mac.raw = skb->data;
netif_rx(skb);
@@ -1188,7 +1264,6 @@
goto unlock;
}
ipt = ippp_table[slot];
- lp->huptimer = 0;

/*
* after this line .. requeueing in the device queue is no longer allowed!!!
@@ -1199,6 +1274,34 @@
*/
skb_pull(skb,IPPP_MAX_HEADER);

+#ifdef CONFIG_IPPP_FILTER
+ /* check if we should pass this packet
+ * the filter instructions are constructed assuming
+ * a four-byte PPP header on each packet */
+ skb_push(skb, 4);
+ skb->data[0] = 1; /* indicate outbound */
+ *(u_int16_t *)(skb->data + 2) = htons(proto);
+
+ if (ipt->pass_filter.filter
+ && sk_run_filter(skb, ipt->pass_filter.filter,
+ ipt->pass_filter.len) == 0) {
+ if (ipt->debug & 0x4)
+ printk(KERN_DEBUG "IPPP: outbound frame filtered.\n");
+ kfree_skb(skb);
+ goto unlock;
+ }
+ if (!(ipt->active_filter.filter
+ && sk_run_filter(skb, ipt->active_filter.filter,
+ ipt->active_filter.len) == 0)) {
+ if (ipt->debug & 0x4)
+ printk(KERN_DEBUG "IPPP: link-active filter: reseting huptimer.\n");
+ lp->huptimer = 0;
+ }
+ skb_pull(skb, 4);
+#else /* CONFIG_IPPP_FILTER */
+ lp->huptimer = 0;
+#endif /* CONFIG_IPPP_FILTER */
+
if (ipt->debug & 0x4)
printk(KERN_DEBUG "xmit skb, len %d\n", (int) skb->len);
if (ipts->debug & 0x40)
@@ -1340,6 +1443,50 @@
return retval;
}

+#ifdef CONFIG_IPPP_FILTER
+/*
+ * check if this packet may trigger auto-dial.
+ */
+
+int isdn_ppp_autodial_filter(struct sk_buff *skb, isdn_net_local *lp)
+{
+ struct ippp_struct *is = ippp_table[lp->ppp_slot];
+ u_int16_t proto;
+ int drop = 0;
+
+ switch (ntohs(skb->protocol)) {
+ case ETH_P_IP:
+ proto = PPP_IP;
+ break;
+ case ETH_P_IPX:
+ proto = PPP_IPX;
+ break;
+ default:
+ printk(KERN_ERR "isdn_ppp_autodial_filter: unsupported protocol 0x%x.\n",
+ skb->protocol);
+ return 1;
+ }
+
+ /* the filter instructions are constructed assuming
+ * a four-byte PPP header on each packet. we have to
+ * temporarily remove part of the fake header stuck on
+ * earlier.
+ */
+ skb_pull(skb, IPPP_MAX_HEADER - 4);
+ skb->data[0] = 1; /* indicate outbound */
+ *(u_int16_t *)(skb->data + 2) = htons(proto);
+
+ drop |= is->pass_filter.filter
+ && sk_run_filter(skb, is->pass_filter.filter,
+ is->pass_filter.len) == 0;
+ drop |= is->active_filter.filter
+ && sk_run_filter(skb, is->active_filter.filter,
+ is->active_filter.len) == 0;
+
+ skb_push(skb, IPPP_MAX_HEADER - 4);
+ return drop;
+}
+#endif
#ifdef CONFIG_ISDN_MPP

/* this is _not_ rfc1990 header, but something we convert both short and long
diff -urN linux-2.4.20-clean/drivers/isdn/isdn_ppp.h linux-2.4.20_ippp-filter/drivers/isdn/isdn_ppp.h
--- linux-2.4.20-clean/drivers/isdn/isdn_ppp.h 2001-12-21 18:41:54.000000000 +0100
+++ linux-2.4.20_ippp-filter/drivers/isdn/isdn_ppp.h 2003-02-10 23:27:05.000000000 +0100
@@ -19,6 +19,7 @@
extern void isdn_ppp_cleanup(void);
extern int isdn_ppp_free(isdn_net_local *);
extern int isdn_ppp_bind(isdn_net_local *);
+extern int isdn_ppp_autodial_filter(struct sk_buff *, isdn_net_local *);
extern int isdn_ppp_xmit(struct sk_buff *, struct net_device *);
extern void isdn_ppp_receive(isdn_net_dev *, isdn_net_local *, struct sk_buff *);
extern int isdn_ppp_dev_ioctl(struct net_device *, struct ifreq *, int);
diff -urN linux-2.4.20-clean/include/linux/isdn_ppp.h linux-2.4.20_ippp-filter/include/linux/isdn_ppp.h
--- linux-2.4.20-clean/include/linux/isdn_ppp.h 2001-09-30 21:26:42.000000000 +0200
+++ linux-2.4.20_ippp-filter/include/linux/isdn_ppp.h 2003-02-10 23:27:05.000000000 +0100
@@ -65,6 +65,9 @@

#include <linux/config.h>

+#ifdef CONFIG_IPPP_FILTER
+#include <linux/filter.h>
+#endif

#define DECOMP_ERR_NOMEM (-10)

@@ -223,6 +226,10 @@
unsigned char *cbuf;
struct slcompress *slcomp;
#endif
+#ifdef CONFIG_IPPP_FILTER
+ struct sock_fprog pass_filter; /* filter for packets to pass */
+ struct sock_fprog active_filter; /* filter for pkts to reset idle */
+#endif
unsigned long debug;
struct isdn_ppp_compressor *compressor,*decompressor;
struct isdn_ppp_compressor *link_compressor,*link_decompressor;diff -urN isdn4k-utils-clean/ipppd/ipppd.h isdn4k-utils_ippp-filter/ipppd/ipppd.h
--- isdn4k-utils-clean/ipppd/ipppd.h 2002-07-06 02:34:08.000000000 +0200
+++ isdn4k-utils_ippp-filter/ipppd/ipppd.h 2003-01-27 12:56:54.000000000 +0100
@@ -215,6 +215,11 @@
#ifdef __linux__
extern int hostroute; /* Add a route to the host at the other end? */
#endif
+#ifdef IPPP_FILTER
+#include <net/bpf.h>
+extern struct bpf_program pass_filter; /* Filter for pkts to pass */
+extern struct bpf_program active_filter; /* Filter for link-active pkts */
+#endif /* IPPP_FILTER */

/*
* Values for phase.
@@ -288,6 +293,9 @@
void link_terminated(int);
void link_down(int);
void link_established(int unit);
+#ifdef IPPP_FILTER
+int set_filters(int, struct bpf_program *, struct bpf_program *);
+#endif /* IPPP_FILTER */
int device_script(char *program,int in,int out);
void check_auth_options(void);
void setipdefault(void);
diff -urN isdn4k-utils-clean/ipppd/ippp-filter-compat.h isdn4k-utils_ippp-filter/ipppd/ippp-filter-compat.h
--- isdn4k-utils-clean/ipppd/ippp-filter-compat.h 1970-01-01 01:00:00.000000000 +0100
+++ isdn4k-utils_ippp-filter/ipppd/ippp-filter-compat.h 2003-02-10 06:00:05.000000000 +0100
@@ -0,0 +1,11 @@
+#ifndef _IPPP_FILTER_COMPAT_H
+#define _IPPP_FILTER_COMPAT_T
+
+#ifndef PPPIOCSPASS
+#define PPPIOCSPASS _IOW('t', 71, struct sock_fprog) /* set pass filter */
+#endif
+#ifndef PPPIOCSACTIVE
+#define PPPIOCSACTIVE _IOW('t', 70, struct sock_fprog) /* set active filter */
+#endif
+
+#endif /* _IPPP_FILTER_COMPAT_T */
diff -urN isdn4k-utils-clean/ipppd/main.c isdn4k-utils_ippp-filter/ipppd/main.c
--- isdn4k-utils-clean/ipppd/main.c 2002-07-18 02:06:21.000000000 +0200
+++ isdn4k-utils_ippp-filter/ipppd/main.c 2003-01-27 12:56:54.000000000 +0100
@@ -564,6 +564,9 @@
lns[linkunit].upap_unit = lns[linkunit].chap_unit = lns[linkunit].lcp_unit;
upap[lns[linkunit].upap_unit].us_unit = chap[lns[linkunit].chap_unit].unit = linkunit;
lcp_lowerup(lns[linkunit].lcp_unit);
+#ifdef IPPP_FILTER
+ set_filters(linkunit, &pass_filter, &active_filter);
+#endif /* IPPP_FILTER */

return 0;
}
diff -urN isdn4k-utils-clean/ipppd/options.c isdn4k-utils_ippp-filter/ipppd/options.c
--- isdn4k-utils-clean/ipppd/options.c 2002-07-06 02:34:08.000000000 +0200
+++ isdn4k-utils_ippp-filter/ipppd/options.c 2003-02-10 06:06:03.000000000 +0100
@@ -39,6 +39,10 @@
#include <radiusclient.h>
#endif

+#ifdef IPPP_FILTER
+#include <pcap.h>
+#endif /* IPPP_FILTER */
+
#include "fsm.h"
#include "ipppd.h"
#include "pathnames.h"
@@ -140,6 +144,10 @@
struct option_info auth_req_info;
struct option_info devnam_info;

+#ifdef IPPP_FILTER
+struct bpf_program pass_filter;/* Filter program for packets to pass */
+struct bpf_program active_filter; /* Filter program for link-active pkts */
+#endif /* IPPP_FILTER */

/*
* Prototypes
@@ -292,6 +300,11 @@
int __P (radius_init ( void ));
#endif

+#ifdef IPPP_FILTER
+static int setpassfilter __P((int,char **));
+static int setactivefilter __P((int,char **));
+#endif /* IPPP_FILTER */
+
/*
* Valid arguments.
*/
@@ -470,7 +483,10 @@
{"nohostroute", 0, setnohostroute}, /* Don't add host route */
#endif
{"+force-driver",0,setforcedriver},
-
+#ifdef IPPP_FILTER
+ { "pass-filter", 1, setpassfilter}, /* pass filter */
+ { "active-filter", 1, setactivefilter}, /* link-active filter */
+#endif /* IPPP_FILTER */
{NULL, 0, NULL}
};

@@ -2615,3 +2631,33 @@
force_driver = 1;
return 1;
}
+
+#ifdef IPPP_FILTER
+/*
+ * setpassfilter - Set the pass filter for packets
+ */
+static int
+setpassfilter(argc, argv)
+ int argc;
+ char **argv;
+{
+ if (pcap_compile_nopcap(PPP_HDRLEN, DLT_PPP, &pass_filter, *argv, 1, netmask) == 0)
+ return 1;
+ option_error("error in pass-filter expression.\n");
+ return 0;
+}
+
+/*
+ * setactivefilter - Set the active filter for packets
+ */
+static int
+setactivefilter(argc, argv)
+ int argc;
+ char **argv;
+{
+ if (pcap_compile_nopcap(PPP_HDRLEN, DLT_PPP, &active_filter, *argv, 1, netmask) == 0)
+ return 1;
+ option_error("error in active-filter expression.\n");
+ return 0;
+}
+#endif /* IPPP_FILTER */
diff -urN isdn4k-utils-clean/ipppd/sys-linux.c isdn4k-utils_ippp-filter/ipppd/sys-linux.c
--- isdn4k-utils-clean/ipppd/sys-linux.c 2000-10-05 22:45:25.000000000 +0200
+++ isdn4k-utils_ippp-filter/ipppd/sys-linux.c 2003-02-10 06:00:35.000000000 +0100
@@ -57,6 +57,7 @@
#if defined __GLIBC__ && __GLIBC__ >= 2
# include </usr/include/net/ppp_defs.h>
# include </usr/include/net/if_ppp.h>
+# include "ippp-filter-compat.h"
# include </usr/include/net/ethernet.h>
# include "route.h"
#else
@@ -70,6 +71,11 @@
# include <netipx/ipx.h>
#endif

+#ifdef IPPP_FILTER
+#include <net/bpf.h>
+#include <linux/filter.h>
+#endif /* IPPP_FILTER */
+
#include "fsm.h"
#include "ipppd.h"
#include "ipcp.h"
@@ -515,6 +521,40 @@
return 1;
}

+#ifdef IPPP_FILTER
+/*
+ * set_filters - set the active and pass filters in the kernel driver.
+ */
+int set_filters(int u, struct bpf_program *pass, struct bpf_program *active)
+{
+ struct sock_fprog fp;
+
+ /*
+ * unfortunately there is no way of checking for kernel support. the
+ * driver just returns 0 for unsupported ioctls, which means without
+ * kernel support we won't even notice the error.
+ */
+
+ if (pass) {
+ fp.len = pass->bf_len;
+ fp.filter = (struct sock_filter *) pass->bf_insns;
+ if (ioctl(lns[u].fd, PPPIOCSPASS, &fp) < 0) {
+ syslog(LOG_ERR, "Couldn't set pass-filter in kernel.");
+ return 0;
+ }
+ }
+ if (active) {
+ fp.len = active->bf_len;
+ fp.filter = (struct sock_filter *) active->bf_insns;
+ if (ioctl(lns[u].fd, PPPIOCSACTIVE, &fp) < 0) {
+ syslog(LOG_ERR, "Couldn't set active-filter in kernel.");
+ return 0;
+ }
+ }
+ return 1;
+}
+#endif /* IPPP_FILTER */
+
/*
* sifup - Config the interface up and enable IP packets to pass.
*/
\
 
 \ /
  Last update: 2005-03-22 13:33    [W:0.125 / U:1.640 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site