From 76307d910b81acb709143b2fd82e1ca724feb24c Mon Sep 17 00:00:00 2001
From: Paul Mackerras <paulus@samba.org>
Date: Sun, 15 Jun 2008 04:35:50 +0000
Subject: [PATCH] Add pppoe-mac option to rp-pppoe plugin

This allows the user to specify the MAC address of the pppoe
server that s/he wishes to use.  With this option, pppd will
ignore PADO packets from any other MAC address.
---
 pppd/plugins/rp-pppoe/discovery.c |  9 +++++++--
 pppd/plugins/rp-pppoe/plugin.c    | 21 ++++++++++++++++++++-
 pppd/plugins/rp-pppoe/pppoe.h     |  4 +++-
 3 files changed, 30 insertions(+), 4 deletions(-)

diff --git a/pppd/plugins/rp-pppoe/discovery.c b/pppd/plugins/rp-pppoe/discovery.c
index dc61489..6e25ae7 100644
--- a/pppd/plugins/rp-pppoe/discovery.c
+++ b/pppd/plugins/rp-pppoe/discovery.c
@@ -9,7 +9,7 @@
 ***********************************************************************/
 
 static char const RCSID[] =
-"$Id: discovery.c,v 1.5 2008/06/09 08:34:23 paulus Exp $";
+"$Id: discovery.c,v 1.6 2008/06/15 04:35:50 paulus Exp $";
 
 #define _GNU_SOURCE 1
 #include "pppoe.h"
@@ -274,7 +274,7 @@ sendPADI(PPPoEConnection *conn)
 *%DESCRIPTION:
 * Waits for a PADO packet and copies useful information
 ***********************************************************************/
-static void
+void
 waitForPADO(PPPoEConnection *conn, int timeout)
 {
     fd_set readable;
@@ -333,6 +333,11 @@ waitForPADO(PPPoEConnection *conn, int timeout)
 		error("Ignoring PADO packet from non-unicast MAC address");
 		continue;
 	    }
+	    if (conn->req_peer
+		&& memcmp(packet.ethHdr.h_source, conn->req_peer_mac, ETH_ALEN) != 0) {
+		warn("Ignoring PADO packet from wrong MAC address");
+		continue;
+	    }
 	    if (parsePacket(&packet, parsePADOTags, &pc) < 0)
 		return;
 	    if (conn->error)
diff --git a/pppd/plugins/rp-pppoe/plugin.c b/pppd/plugins/rp-pppoe/plugin.c
index 2968e72..e94494b 100644
--- a/pppd/plugins/rp-pppoe/plugin.c
+++ b/pppd/plugins/rp-pppoe/plugin.c
@@ -23,7 +23,7 @@
 ***********************************************************************/
 
 static char const RCSID[] =
-"$Id: plugin.c,v 1.16 2008/06/09 08:34:23 paulus Exp $";
+"$Id: plugin.c,v 1.17 2008/06/15 04:35:50 paulus Exp $";
 
 #define _GNU_SOURCE 1
 #include "pppoe.h"
@@ -67,6 +67,8 @@ char *pppd_pppoe_service = NULL;
 static char *acName = NULL;
 static char *existingSession = NULL;
 static int printACNames = 0;
+static char *pppoe_reqd_mac = NULL;
+unsigned char pppoe_reqd_mac_addr[6];
 
 static int PPPoEDevnameHook(char *cmd, char **argv, int doit);
 static option_t Options[] = {
@@ -82,6 +84,8 @@ static option_t Options[] = {
       "Attach to existing session (sessid:macaddr)" },
     { "rp_pppoe_verbose", o_int, &printACNames,
       "Be verbose about discovered access concentrators"},
+    { "pppoe-mac", o_string, &pppoe_reqd_mac,
+      "Only connect to specified MAC address" },
     { NULL }
 };
 int (*OldDevnameHook)(char *cmd, char **argv, int doit) = NULL;
@@ -348,6 +352,21 @@ plugin_init(void)
 
 void pppoe_check_options(void)
 {
+    unsigned int mac[6];
+    int i;
+
+    if (pppoe_reqd_mac != NULL) {
+	if (sscanf(pppoe_reqd_mac, "%x:%x:%x:%x:%x:%x",
+		   &mac[0], &mac[1], &mac[2], &mac[3],
+		   &mac[4], &mac[5]) != 6) {
+	    option_error("cannot parse pppoe-mac option value");
+	    exit(EXIT_OPTION_ERROR);
+	}
+	for (i = 0; i < 6; ++i)
+	    conn->req_peer_mac[i] = mac[i];
+	conn->req_peer = 1;
+    }
+
     lcp_allowoptions[0].neg_accompression = 0;
     lcp_wantoptions[0].neg_accompression = 0;
 
diff --git a/pppd/plugins/rp-pppoe/pppoe.h b/pppd/plugins/rp-pppoe/pppoe.h
index a4cf28a..3dba439 100644
--- a/pppd/plugins/rp-pppoe/pppoe.h
+++ b/pppd/plugins/rp-pppoe/pppoe.h
@@ -9,7 +9,7 @@
 * This program may be distributed according to the terms of the GNU
 * General Public License, version 2 or (at your option) any later version.
 *
-* $Id: pppoe.h,v 1.3 2008/06/09 08:34:23 paulus Exp $
+* $Id: pppoe.h,v 1.4 2008/06/15 04:35:50 paulus Exp $
 *
 ***********************************************************************/
 
@@ -217,6 +217,8 @@ typedef struct PPPoEConnectionStruct {
     int sessionSocket;		/* Raw socket for session frames */
     unsigned char myEth[ETH_ALEN]; /* My MAC address */
     unsigned char peerEth[ETH_ALEN]; /* Peer's MAC address */
+    unsigned char req_peer_mac[ETH_ALEN]; /* required peer MAC address */
+    unsigned char req_peer;	/* require mac addr to match req_peer_mac */
     UINT16_t session;		/* Session ID */
     char *ifName;		/* Interface name */
     char *serviceName;		/* Desired service name, if any */
-- 
2.39.2