[PATCH] pppoe: custom host-uniq tag

Add pppoe 'host-uniq' option to set an arbitrary
host-uniq tag instead of the pppd pid.
Some ISPs use such tag to authenticate the CPE,
so it must be set to a proper value to connect.

Signed-off-by: Matteo Croce <matteo@openwrt.org>
Signed-off-by: Jo-Philipp Wich <jow@openwrt.org>

Gbp-Pq: Name pr-28-pppoe-custom-host-uniq-tag.patch

pppd/plugins/rp-pppoe/common.c

@@ -119,15 +119,11 @@ sendPADT(PPPoEConnection *conn, char const *msg)
     conn->session = 0;
 
     /* If we're using Host-Uniq, copy it over */
-    if (conn->useHostUniq) {
+    if (conn->hostUniq.length) {
-	PPPoETag hostUniq;
+	int len = ntohs(conn->hostUniq.length);
-	pid_t pid = getpid();
+	memcpy(cursor, &conn->hostUniq, len + TAG_HDR_SIZE);
-	hostUniq.type = htons(TAG_HOST_UNIQ);
+	cursor += len + TAG_HDR_SIZE;
-	hostUniq.length = htons(sizeof(pid));
+	plen += len + TAG_HDR_SIZE;
-	memcpy(hostUniq.payload, &pid, sizeof(pid));
-	memcpy(cursor, &hostUniq, sizeof(pid) + TAG_HDR_SIZE);
-	cursor += sizeof(pid) + TAG_HDR_SIZE;
-	plen += sizeof(pid) + TAG_HDR_SIZE;
     }
 
     /* Copy error message */

pppd/plugins/rp-pppoe/discovery.c

@@ -80,13 +80,10 @@ static void
 parseForHostUniq(UINT16_t type, UINT16_t len, unsigned char *data,
 		 void *extra)
 {
-    int *val = (int *) extra;
+    PPPoETag *tag = extra;
-    if (type == TAG_HOST_UNIQ && len == sizeof(pid_t)) {
+
-	pid_t tmp;
+    if (type == TAG_HOST_UNIQ && len == ntohs(tag->length)) {
-	memcpy(&tmp, data, len);
+	tag->length = memcmp(data, tag->payload, len);
-	if (tmp == getpid()) {
-	    *val = 1;
-	}
     }
 }
 
@@ -104,16 +101,16 @@ parseForHostUniq(UINT16_t type, UINT16_t len, unsigned char *data,
 static int
 packetIsForMe(PPPoEConnection *conn, PPPoEPacket *packet)
 {
-    int forMe = 0;
+    PPPoETag hostUniq = conn->hostUniq;
 
     /* If packet is not directed to our MAC address, forget it */
     if (memcmp(packet->ethHdr.h_dest, conn->myEth, ETH_ALEN)) return 0;
 
     /* If we're not using the Host-Unique tag, then accept the packet */
-    if (!conn->useHostUniq) return 1;
+    if (!conn->hostUniq.length) return 1;
 
-    parsePacket(packet, parseForHostUniq, &forMe);
+    parsePacket(packet, parseForHostUniq, &hostUniq);
-    return forMe;
+    return !hostUniq.length;
 }
 
 /**********************************************************************
@@ -301,16 +298,12 @@ sendPADI(PPPoEConnection *conn)
     }
 
     /* If we're using Host-Uniq, copy it over */
-    if (conn->useHostUniq) {
+    if (conn->hostUniq.length) {
-	PPPoETag hostUniq;
+	int len = ntohs(conn->hostUniq.length);
-	pid_t pid = getpid();
+	CHECK_ROOM(cursor, packet.payload, len + TAG_HDR_SIZE);
-	hostUniq.type = htons(TAG_HOST_UNIQ);
+	memcpy(cursor, &conn->hostUniq, len + TAG_HDR_SIZE);
-	hostUniq.length = htons(sizeof(pid));
+	cursor += len + TAG_HDR_SIZE;
-	memcpy(hostUniq.payload, &pid, sizeof(pid));
+	plen += len + TAG_HDR_SIZE;
-	CHECK_ROOM(cursor, packet.payload, sizeof(pid) + TAG_HDR_SIZE);
-	memcpy(cursor, &hostUniq, sizeof(pid) + TAG_HDR_SIZE);
-	cursor += sizeof(pid) + TAG_HDR_SIZE;
-	plen += sizeof(pid) + TAG_HDR_SIZE;
     }
 
     /* Add our maximum MTU/MRU */
@@ -478,16 +471,12 @@ sendPADR(PPPoEConnection *conn)
     cursor += namelen + TAG_HDR_SIZE;
 
     /* If we're using Host-Uniq, copy it over */
-    if (conn->useHostUniq) {
+    if (conn->hostUniq.length) {
-	PPPoETag hostUniq;
+	int len = ntohs(conn->hostUniq.length);
-	pid_t pid = getpid();
+	CHECK_ROOM(cursor, packet.payload, len+TAG_HDR_SIZE);
-	hostUniq.type = htons(TAG_HOST_UNIQ);
+	memcpy(cursor, &conn->hostUniq, len + TAG_HDR_SIZE);
-	hostUniq.length = htons(sizeof(pid));
+	cursor += len + TAG_HDR_SIZE;
-	memcpy(hostUniq.payload, &pid, sizeof(pid));
+	plen += len + TAG_HDR_SIZE;
-	CHECK_ROOM(cursor, packet.payload, sizeof(pid)+TAG_HDR_SIZE);
-	memcpy(cursor, &hostUniq, sizeof(pid) + TAG_HDR_SIZE);
-	cursor += sizeof(pid) + TAG_HDR_SIZE;
-	plen += sizeof(pid) + TAG_HDR_SIZE;
     }
 
     /* Add our maximum MTU/MRU */

pppd/plugins/rp-pppoe/plugin.c

@@ -68,6 +68,7 @@ static char *existingSession = NULL;
 static int printACNames = 0;
 static char *pppoe_reqd_mac = NULL;
 unsigned char pppoe_reqd_mac_addr[6];
+static char *host_uniq = NULL;
 
 static int PPPoEDevnameHook(char *cmd, char **argv, int doit);
 static option_t Options[] = {
@@ -85,6 +86,8 @@ static option_t Options[] = {
       "Be verbose about discovered access concentrators"},
     { "pppoe-mac", o_string, &pppoe_reqd_mac,
       "Only connect to specified MAC address" },
+    { "host-uniq", o_string, &host_uniq,
+      "Specify custom Host-Uniq" },
     { NULL }
 };
 int (*OldDevnameHook)(char *cmd, char **argv, int doit) = NULL;
@@ -110,7 +113,6 @@ PPPOEInitDevice(void)
     conn->ifName = devnam;
     conn->discoverySocket = -1;
     conn->sessionSocket = -1;
-    conn->useHostUniq = 1;
     conn->printACNames = printACNames;
     conn->discoveryTimeout = PADI_TIMEOUT;
     return 1;
@@ -166,6 +168,9 @@ PPPOEConnectDevice(void)
     if (lcp_wantoptions[0].mru > ifr.ifr_mtu - TOTAL_OVERHEAD)
 	lcp_wantoptions[0].mru = ifr.ifr_mtu - TOTAL_OVERHEAD;
 
+    if (host_uniq && !parseHostUniq(host_uniq, &conn->hostUniq))
+	fatal("Illegal value for host-uniq option");
+
     conn->acName = acName;
     conn->serviceName = pppd_pppoe_service;
     strlcpy(ppp_devnam, devnam, sizeof(ppp_devnam));

pppd/plugins/rp-pppoe/pppoe-discovery.c

@@ -356,7 +356,7 @@ packetIsForMe(PPPoEConnection *conn, PPPoEPacket *packet)
     if (memcmp(packet->ethHdr.h_dest, conn->myEth, ETH_ALEN)) return 0;
 
     /* If we're not using the Host-Unique tag, then accept the packet */
-    if (!conn->useHostUniq) return 1;
+    if (!conn->hostUniq.length) return 1;
 
     parsePacket(packet, parseForHostUniq, &forMe);
     return forMe;
@@ -482,16 +482,12 @@ sendPADI(PPPoEConnection *conn)
     cursor += namelen + TAG_HDR_SIZE;
 
     /* If we're using Host-Uniq, copy it over */
-    if (conn->useHostUniq) {
+    if (conn->hostUniq.length) {
-	PPPoETag hostUniq;
+	int len = ntohs(conn->hostUniq.length);
-	pid_t pid = getpid();
+	CHECK_ROOM(cursor, packet.payload, len + TAG_HDR_SIZE);
-	hostUniq.type = htons(TAG_HOST_UNIQ);
+	memcpy(cursor, &conn->hostUniq, len + TAG_HDR_SIZE);
-	hostUniq.length = htons(sizeof(pid));
+	cursor += len + TAG_HDR_SIZE;
-	memcpy(hostUniq.payload, &pid, sizeof(pid));
+	plen += len + TAG_HDR_SIZE;
-	CHECK_ROOM(cursor, packet.payload, sizeof(pid) + TAG_HDR_SIZE);
-	memcpy(cursor, &hostUniq, sizeof(pid) + TAG_HDR_SIZE);
-	cursor += sizeof(pid) + TAG_HDR_SIZE;
-	plen += sizeof(pid) + TAG_HDR_SIZE;
     }
 
     packet.length = htons(plen);
@@ -653,7 +649,7 @@ int main(int argc, char *argv[])
 
     memset(conn, 0, sizeof(PPPoEConnection));
 
-    while ((opt = getopt(argc, argv, "I:D:VUAS:C:h")) > 0) {
+    while ((opt = getopt(argc, argv, "I:D:VUW:AS:C:h")) > 0) {
 	switch(opt) {
 	case 'S':
 	    conn->serviceName = xstrdup(optarg);
@@ -662,7 +658,23 @@ int main(int argc, char *argv[])
 	    conn->acName = xstrdup(optarg);
 	    break;
 	case 'U':
-	    conn->useHostUniq = 1;
+	    if(conn->hostUniq.length) {
+		fprintf(stderr, "-U and -W are mutually exclusive\n");
+		exit(EXIT_FAILURE);
+	    }
+            char pidbuf[5];
+            snprintf(pidbuf, sizeof(pidbuf), "%04x", getpid());
+            parseHostUniq(pidbuf, &conn->hostUniq);
+	    break;
+	case 'W':
+	    if(conn->hostUniq.length) {
+		fprintf(stderr, "-U and -W are mutually exclusive\n");
+		exit(EXIT_FAILURE);
+	    }
+	    if (!parseHostUniq(optarg, &conn->hostUniq)) {
+                fprintf(stderr, "Invalid host-uniq argument: %s\n", optarg);
+                exit(EXIT_FAILURE);
+            }
 	    break;
 	case 'D':
 	    conn->debugFile = fopen(optarg, "w");

pppd/plugins/rp-pppoe/pppoe.h

@@ -21,6 +21,8 @@
 
 #include <stdio.h>		/* For FILE */
 #include <sys/types.h>		/* For pid_t */
+#include <ctype.h>
+#include <string.h>
 
 /* How do we access raw Ethernet devices? */
 #undef USE_LINUX_PACKET
@@ -236,7 +238,7 @@ typedef struct PPPoEConnectionStruct {
     char *serviceName;		/* Desired service name, if any */
     char *acName;		/* Desired AC name, if any */
     int synchronous;		/* Use synchronous PPP */
-    int useHostUniq;		/* Use Host-Uniq tag */
+    PPPoETag hostUniq;		/* Use Host-Uniq tag */
     int printACNames;		/* Just print AC names */
     FILE *debugFile;		/* Debug file for dumping packets */
     int numPADOs;		/* Number of PADO packets received */
@@ -292,6 +294,33 @@ void pppoe_printpkt(PPPoEPacket *packet,
 		    void (*printer)(void *, char *, ...), void *arg);
 void pppoe_log_packet(const char *prefix, PPPoEPacket *packet);
 
+static inline int parseHostUniq(const char *uniq, PPPoETag *tag)
+{
+    int i, len = strlen(uniq);
+
+#define hex(x) \
+    (((x) <= '9') ? ((x) - '0') : \
+        (((x) <= 'F') ? ((x) - 'A' + 10) : \
+            ((x) - 'a' + 10)))
+
+    if (len % 2)
+        return 0;
+
+    for (i = 0; i < len; i += 2)
+    {
+        if (!isxdigit(uniq[i]) || !isxdigit(uniq[i+1]))
+            return 0;
+
+        tag->payload[i / 2] = (char)(16 * hex(uniq[i]) + hex(uniq[i+1]));
+    }
+
+#undef hex
+
+    tag->type = htons(TAG_HOST_UNIQ);
+    tag->length = htons(len / 2);
+    return 1;
+}
+
 #define SET_STRING(var, val) do { if (var) free(var); var = strDup(val); } while(0);
 
 #define CHECK_ROOM(cursor, start, len) \