pppoe-server: -n to use vendor specific tag as remote*N*umber.

RFC 2516 discourages it's use but it looks like at least some switches
adds a port-configured circuit-id throught this.  This does not seem to
be well defined but at least CISCO and the S3900 series switches from
fs.com has stuff about this in the documentation, which leads me to
believe it's common practise.

Signed-off-by: Jaco Kroon <[email protected]>

src/pppoe-server.c

@@ -99,6 +99,8 @@ int NumInterfaces = 0;
 int MaxInterfaces = 0;
 int draining = 0;
 
+int vendorTagAsRemoteNumber = 0;
+
 /* The number of session slots */
 size_t NumSessionSlots;
 
@@ -176,6 +178,7 @@ static PPPoETag hostUniq;
 static PPPoETag relayId;
 static PPPoETag receivedCookie;
 static PPPoETag requestedService;
+static PPPoETag vendorTag;
 
 #define HOSTNAMELEN 256
 
@@ -514,6 +517,11 @@ parsePADRTags(uint16_t type, uint16_t len, unsigned char *data,
 	requestedService.length = htons(len);
 	memcpy(requestedService.payload, data, len);
 	break;
+    case TAG_VENDOR_SPECIFIC:
+	vendorTag.type = htons(type);
+	vendorTag.length = htons(len);
+	memcpy(vendorTag.payload, data, len);
+	break;
     }
 }
 
@@ -881,6 +889,7 @@ processPADR(Interface *ethif, PPPoEPacket *packet, int len)
     hostUniq.type = 0;
     receivedCookie.type = 0;
     requestedService.type = 0;
+    vendorTag.type = 0;
 
     /* Ignore PADR's not directed at us */
     if (memcmp(packet->ethHdr.h_dest, myAddr, ETH_ALEN)) return;
@@ -979,6 +988,7 @@ processPADR(Interface *ethif, PPPoEPacket *packet, int len)
     cliSession->funcs = &DefaultSessionFunctionTable;
     cliSession->startTime = time(NULL);
     cliSession->serviceName = serviceName;
+    cliSession->remoteNumber = NULL;
 
     /* Create child process, send PADS packet back */
     child = fork();
@@ -1071,6 +1081,10 @@ processPADR(Interface *ethif, PPPoEPacket *packet, int len)
 	cursor += ntohs(hostUniq.length) + TAG_HDR_SIZE;
 	plen += ntohs(hostUniq.length) + TAG_HDR_SIZE;
     }
+    if (vendorTag.type && ntohs(vendorTag.length) > TAG_HDR_SIZE && vendorTagAsRemoteNumber) {
+	vendorTag.payload[ntohs(vendorTag.length)] = 0; /* Make sure it's NUL terminated */
+	cliSession->remoteNumber = (char*)vendorTag.payload + TAG_HDR_SIZE;
+    }
     pads.length = htons(plen);
     sendPacket(NULL, sock, &pads, (int) (plen + HDR_SIZE));
 
@@ -1209,7 +1223,7 @@ main(int argc, char **argv)
     char const *s;
     int cookie_ok = 0;
 
-    char const *options = "X:ix:hI:C:L:R:T:m:FN:f:O:o:skp:lrudPS:q:Q:H:M:U:g:";
+    char const *options = "X:ix:hI:C:L:R:T:m:FN:f:O:o:skp:lrudPS:q:Q:H:M:U:g:n";
 
     if (getuid() != geteuid() ||
 	getgid() != getegid()) {
@@ -1457,6 +1471,10 @@ main(int argc, char **argv)
 	    SET_STRING(unix_control, optarg);
 	    break;
 
+	case 'n':
+	    vendorTagAsRemoteNumber = 1;
+	    break;
+
 	case 'h':
 	    usage(argv[0]);
 	    exit(EXIT_SUCCESS);
@@ -1989,11 +2007,17 @@ startPPPD(ClientSession *session)
     argv[c++] = "default-asyncmap";
 
     argv[c++] = "remotenumber";
-    snprintf(buffer, SMALLBUF, "%02x:%02x:%02x:%02x:%02x:%02x",
-	    session->eth[0], session->eth[1], session->eth[2],
-	    session->eth[3], session->eth[4], session->eth[5]);
-    if (!(argv[c++] = strdup(buffer))) {
-	exit(EXIT_FAILURE);
+    if (session->remoteNumber) {
+	if (!(argv[c++] = strdup(session->remoteNumber))) {
+	    exit(EXIT_FAILURE);
+	}
+    } else {
+	snprintf(buffer, SMALLBUF, "%02x:%02x:%02x:%02x:%02x:%02x",
+		session->eth[0], session->eth[1], session->eth[2],
+		session->eth[3], session->eth[4], session->eth[5]);
+	if (!(argv[c++] = strdup(buffer))) {
+	    exit(EXIT_FAILURE);
+	}
     }
 
     if (PassUnitOptionToPPPD) {

src/pppoe-server.h

@@ -78,6 +78,7 @@ typedef struct ClientSessionStruct {
     time_t startTime;		/* When session started */
     char const *serviceName;	/* Service name */
     uint16_t requested_mtu;     /* Requested PPP_MAX_PAYLOAD  per RFC 4638 */
+    char *remoteNumber;    /* Vendor-Specific tag extracted remote number ... this is a bit of a hack */
 } ClientSession;
 
 /* Hack for daemonizing */