--- ./pppd/plugins/rp-pppoe/discovery.c~	2005-03-22 11:22:32 +0100
+++ ./pppd/plugins/rp-pppoe/discovery.c	2007-05-28 10:20:03 +0200
@@ -351,18 +351,49 @@
 	    continue;
 	}
 
-#ifdef USE_BPF
 	/* If it's not a Discovery packet, loop again */
-	if (etherType(&packet) != Eth_PPPOE_Discovery) continue;
-#endif
+	if (etherType(&packet) == Eth_PPPOE_Session)
+		goto reset_packet;
+	if (etherType(&packet) != Eth_PPPOE_Discovery)
+		continue;
 
 	if (conn->debugFile) {
 	    dumpPacket(conn->debugFile, &packet, "RCVD");
 	    fprintf(conn->debugFile, "\n");
 	    fflush(conn->debugFile);
 	}
-	/* If it's not for us, loop again */
-	if (!packetIsForMe(conn, &packet)) continue;
+	/* If it's not for us, we should not have received it. So we will send
+	 * a PADT in the following situations :
+	 *  - invalid MAC destination received
+	 *    => possibly means the hardware was replaced
+	 *  - a session is known and it does not match the sessin received
+	 *    => means pppd has been restarted / machine rebooted
+	 *  - no session is known yet and the packet is not a PADO
+	 *    => means and older session was not killed
+	 * After that we we loop again.
+	 */
+	if (!packetIsForMe(conn, &packet) ||
+	    (conn->session && packet.session && packet.session != conn->session) ||
+	    (packet.code != CODE_PADO && packet.code != CODE_PADT)) {
+		PPPoEConnection *tmp_conn;
+	reset_packet:
+		tmp_conn = (PPPoEConnection *)calloc(1, sizeof(PPPoEConnection));
+		if (!tmp_conn)
+			continue;
+		memcpy(tmp_conn, conn, sizeof(*tmp_conn));
+
+		memcpy(tmp_conn->peerEth, packet.ethHdr.h_source, ETH_ALEN);
+		memcpy(conn->myEth, packet.ethHdr.h_dest, ETH_ALEN);
+		tmp_conn->session = packet.session;
+		tmp_conn->cookie.type = 0;
+		tmp_conn->relayId.type = 0;
+		sendPADT(tmp_conn, NULL);
+		free(tmp_conn);
+		/* The previous packet was ignored. Let's resend it. */
+		sleep(1);
+		sendPADI(conn);
+		continue;
+	}
 
 	if (packet.code == CODE_PADO) {
 	    if (BROADCAST(packet.ethHdr.h_source)) {
@@ -528,10 +559,12 @@
 	    continue;
 	}
 
-#ifdef USE_BPF
 	/* If it's not a Discovery packet, loop again */
-	if (etherType(&packet) != Eth_PPPOE_Discovery) continue;
-#endif
+	if (etherType(&packet) == Eth_PPPOE_Session)
+		goto reset_packet;
+	if (etherType(&packet) != Eth_PPPOE_Discovery)
+		continue;
+
 	if (conn->debugFile) {
 	    dumpPacket(conn->debugFile, &packet, "RCVD");
 	    fprintf(conn->debugFile, "\n");
@@ -541,8 +574,40 @@
 	/* If it's not from the AC, it's not for me */
 	if (memcmp(packet.ethHdr.h_source, conn->peerEth, ETH_ALEN)) continue;
 
-	/* If it's not for us, loop again */
-	if (!packetIsForMe(conn, &packet)) continue;
+	/* If it's not for us, we should not have received it. So we will send
+	 * a PADT in the following situations :
+	 *  - invalid MAC destination received
+	 *    => possibly means our hardware was replaced
+	 *  - a session is known and it does not match the session received
+	 *    => means pppd has been restarted / machine rebooted
+	 *  - no session is known yet and the packet is not a PADS nor a PADO
+	 *    => means and older session was not properly killed
+	 *  - it was a data packet or anything we don't expect at this stage
+	 *    => probably that pppd was restarted during a live session
+	 * After that we we loop again.
+	 */
+	if (!packetIsForMe(conn, &packet) ||
+	    (conn->session && packet.session && packet.session != conn->session) ||
+	    (packet.code != CODE_PADS && packet.code != CODE_PADO &&
+	     packet.code != CODE_PADT)) {
+		PPPoEConnection *tmp_conn;
+	reset_packet:
+		tmp_conn = (PPPoEConnection *)calloc(1, sizeof(PPPoEConnection));
+		if (!tmp_conn)
+			continue;
+		memcpy(tmp_conn, conn, sizeof(*tmp_conn));
+		memcpy(tmp_conn->peerEth, packet.ethHdr.h_source, ETH_ALEN);
+		memcpy(conn->myEth, packet.ethHdr.h_dest, ETH_ALEN);
+		tmp_conn->session = packet.session;
+		tmp_conn->cookie.type = 0;
+		tmp_conn->relayId.type = 0;
+		sendPADT(tmp_conn, NULL);
+		free(tmp_conn);
+		/* The previous packet has been dropped. Let's resend it. */
+		sleep(1);
+		sendPADR(conn);
+		continue;
+	}
 
 	/* Is it PADS?  */
 	if (packet.code == CODE_PADS) {
@@ -586,8 +651,10 @@
 	return;
     }
 
+    /* Note: to support session killing, it is important to listen to all
+       protocols, namely Eth_PPPOE_Discovery AND Eth_PPPOE_Session. */
     conn->discoverySocket =
-	openInterface(conn->ifName, Eth_PPPOE_Discovery, conn->myEth);
+	openInterface(conn->ifName, 0, conn->myEth);
 
     /* Skip discovery? */
     if (conn->skipDiscovery) {
--- ./pppd/plugins/rp-pppoe/if.c~	2001-12-14 03:55:20 +0100
+++ ./pppd/plugins/rp-pppoe/if.c	2007-05-28 10:16:43 +0200
@@ -408,7 +408,7 @@
 *%FUNCTION: openInterface
 *%ARGUMENTS:
 * ifname -- name of interface
-* type -- Ethernet frame type
+* type -- Ethernet frame type. 0 means any type.
 * hwaddr -- if non-NULL, set to the hardware address
 *%RETURNS:
 * A raw socket for talking to the Ethernet card.  Exits on error.
@@ -439,6 +439,9 @@
     stype = SOCK_PACKET;
 #endif
 
+    if (!type)
+        type = ETH_P_ALL;
+
     if ((fd = socket(domain, stype, htons(type))) < 0) {
 	/* Give a more helpful message for the common error case */
 	if (errno == EPERM) {