--- /dev/null
+/***********************************************************************
+*
+* discovery.c
+*
+* Perform PPPoE discovery
+*
+* Copyright (C) 1999 by Roaring Penguin Software Inc.
+*
+***********************************************************************/
+
+static char const RCSID[] =
+"$Id: discovery.c,v 1.6 2008/06/15 04:35:50 paulus Exp $";
+
+#define _GNU_SOURCE 1
+#include "pppoe.h"
+#include "pppd/pppd.h"
+#include "pppd/fsm.h"
+#include "pppd/lcp.h"
+
+#include <string.h>
+#include <stdlib.h>
+#include <errno.h>
+
+#ifdef HAVE_SYS_TIME_H
+#include <sys/time.h>
+#endif
+
+#ifdef HAVE_SYS_UIO_H
+#include <sys/uio.h>
+#endif
+
+#ifdef HAVE_UNISTD_H
+#include <unistd.h>
+#endif
+
+#ifdef USE_LINUX_PACKET
+#include <sys/ioctl.h>
+#include <fcntl.h>
+#endif
+
+#include <signal.h>
+
+/* Calculate time remaining until *exp, return 0 if now >= *exp */
+static int time_left(struct timeval *diff, struct timeval *exp)
+{
+ struct timeval now;
+
+ if (get_time(&now) < 0) {
+ error("get_time: %m");
+ return 0;
+ }
+
+ if (now.tv_sec > exp->tv_sec
+ || (now.tv_sec == exp->tv_sec && now.tv_usec >= exp->tv_usec))
+ return 0;
+
+ diff->tv_sec = exp->tv_sec - now.tv_sec;
+ diff->tv_usec = exp->tv_usec - now.tv_usec;
+ if (diff->tv_usec < 0) {
+ diff->tv_usec += 1000000;
+ --diff->tv_sec;
+ }
+
+ return 1;
+}
+
+/**********************************************************************
+*%FUNCTION: parseForHostUniq
+*%ARGUMENTS:
+* type -- tag type
+* len -- tag length
+* data -- tag data.
+* extra -- user-supplied pointer. This is assumed to be a pointer to int.
+*%RETURNS:
+* Nothing
+*%DESCRIPTION:
+* If a HostUnique tag is found which matches our PID, sets *extra to 1.
+***********************************************************************/
+static void
+parseForHostUniq(UINT16_t type, UINT16_t len, unsigned char *data,
+ void *extra)
+{
+ PPPoETag *tag = extra;
+
+ if (type == TAG_HOST_UNIQ && len == ntohs(tag->length))
+ tag->length = memcmp(data, tag->payload, len);
+}
+
+/**********************************************************************
+*%FUNCTION: packetIsForMe
+*%ARGUMENTS:
+* conn -- PPPoE connection info
+* packet -- a received PPPoE packet
+*%RETURNS:
+* 1 if packet is for this PPPoE daemon; 0 otherwise.
+*%DESCRIPTION:
+* If we are using the Host-Unique tag, verifies that packet contains
+* our unique identifier.
+***********************************************************************/
+static int
+packetIsForMe(PPPoEConnection *conn, PPPoEPacket *packet)
+{
+ 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->hostUniq.length) return 1;
+
+ parsePacket(packet, parseForHostUniq, &hostUniq);
+ return !hostUniq.length;
+}
+
+/**********************************************************************
+*%FUNCTION: parsePADOTags
+*%ARGUMENTS:
+* type -- tag type
+* len -- tag length
+* data -- tag data
+* extra -- extra user data. Should point to a PacketCriteria structure
+* which gets filled in according to selected AC name and service
+* name.
+*%RETURNS:
+* Nothing
+*%DESCRIPTION:
+* Picks interesting tags out of a PADO packet
+***********************************************************************/
+static void
+parsePADOTags(UINT16_t type, UINT16_t len, unsigned char *data,
+ void *extra)
+{
+ struct PacketCriteria *pc = (struct PacketCriteria *) extra;
+ PPPoEConnection *conn = pc->conn;
+ UINT16_t mru;
+ int i;
+
+ switch(type) {
+ case TAG_AC_NAME:
+ pc->seenACName = 1;
+ if (conn->printACNames) {
+ info("Access-Concentrator: %.*s", (int) len, data);
+ }
+ if (conn->acName && len == strlen(conn->acName) &&
+ !strncmp((char *) data, conn->acName, len)) {
+ pc->acNameOK = 1;
+ }
+ break;
+ case TAG_SERVICE_NAME:
+ pc->seenServiceName = 1;
+ if (conn->serviceName && len == strlen(conn->serviceName) &&
+ !strncmp((char *) data, conn->serviceName, len)) {
+ pc->serviceNameOK = 1;
+ }
+ break;
+ case TAG_AC_COOKIE:
+ conn->cookie.type = htons(type);
+ conn->cookie.length = htons(len);
+ memcpy(conn->cookie.payload, data, len);
+ break;
+ case TAG_RELAY_SESSION_ID:
+ conn->relayId.type = htons(type);
+ conn->relayId.length = htons(len);
+ memcpy(conn->relayId.payload, data, len);
+ break;
+ case TAG_PPP_MAX_PAYLOAD:
+ if (len == sizeof(mru)) {
+ memcpy(&mru, data, sizeof(mru));
+ mru = ntohs(mru);
+ if (mru >= ETH_PPPOE_MTU) {
+ if (lcp_allowoptions[0].mru > mru)
+ lcp_allowoptions[0].mru = mru;
+ if (lcp_wantoptions[0].mru > mru)
+ lcp_wantoptions[0].mru = mru;
+ conn->seenMaxPayload = 1;
+ }
+ }
+ break;
+ case TAG_SERVICE_NAME_ERROR:
+ error("PADO: Service-Name-Error: %.*s", (int) len, data);
+ conn->error = 1;
+ break;
+ case TAG_AC_SYSTEM_ERROR:
+ error("PADO: System-Error: %.*s", (int) len, data);
+ conn->error = 1;
+ break;
+ case TAG_GENERIC_ERROR:
+ error("PADO: Generic-Error: %.*s", (int) len, data);
+ conn->error = 1;
+ break;
+ }
+}
+
+/**********************************************************************
+*%FUNCTION: parsePADSTags
+*%ARGUMENTS:
+* type -- tag type
+* len -- tag length
+* data -- tag data
+* extra -- extra user data (pointer to PPPoEConnection structure)
+*%RETURNS:
+* Nothing
+*%DESCRIPTION:
+* Picks interesting tags out of a PADS packet
+***********************************************************************/
+static void
+parsePADSTags(UINT16_t type, UINT16_t len, unsigned char *data,
+ void *extra)
+{
+ PPPoEConnection *conn = (PPPoEConnection *) extra;
+ UINT16_t mru;
+ switch(type) {
+ case TAG_SERVICE_NAME:
+ dbglog("PADS: Service-Name: '%.*s'", (int) len, data);
+ break;
+ case TAG_PPP_MAX_PAYLOAD:
+ if (len == sizeof(mru)) {
+ memcpy(&mru, data, sizeof(mru));
+ mru = ntohs(mru);
+ if (mru >= ETH_PPPOE_MTU) {
+ if (lcp_allowoptions[0].mru > mru)
+ lcp_allowoptions[0].mru = mru;
+ if (lcp_wantoptions[0].mru > mru)
+ lcp_wantoptions[0].mru = mru;
+ conn->seenMaxPayload = 1;
+ }
+ }
+ break;
+ case TAG_SERVICE_NAME_ERROR:
+ error("PADS: Service-Name-Error: %.*s", (int) len, data);
+ conn->error = 1;
+ break;
+ case TAG_AC_SYSTEM_ERROR:
+ error("PADS: System-Error: %.*s", (int) len, data);
+ conn->error = 1;
+ break;
+ case TAG_GENERIC_ERROR:
+ error("PADS: Generic-Error: %.*s", (int) len, data);
+ conn->error = 1;
+ break;
+ case TAG_RELAY_SESSION_ID:
+ conn->relayId.type = htons(type);
+ conn->relayId.length = htons(len);
+ memcpy(conn->relayId.payload, data, len);
+ break;
+ }
+}
+
+/***********************************************************************
+*%FUNCTION: sendPADI
+*%ARGUMENTS:
+* conn -- PPPoEConnection structure
+*%RETURNS:
+* Nothing
+*%DESCRIPTION:
+* Sends a PADI packet
+***********************************************************************/
+static void
+sendPADI(PPPoEConnection *conn)
+{
+ PPPoEPacket packet;
+ unsigned char *cursor = packet.payload;
+ PPPoETag *svc = (PPPoETag *) (&packet.payload);
+ UINT16_t namelen = 0;
+ UINT16_t plen;
+ int omit_service_name = 0;
+
+ if (conn->serviceName) {
+ namelen = (UINT16_t) strlen(conn->serviceName);
+ if (!strcmp(conn->serviceName, "NO-SERVICE-NAME-NON-RFC-COMPLIANT")) {
+ omit_service_name = 1;
+ }
+ }
+
+ /* Set destination to Ethernet broadcast address */
+ memset(packet.ethHdr.h_dest, 0xFF, ETH_ALEN);
+ memcpy(packet.ethHdr.h_source, conn->myEth, ETH_ALEN);
+
+ packet.ethHdr.h_proto = htons(Eth_PPPOE_Discovery);
+ packet.vertype = PPPOE_VER_TYPE(1, 1);
+ packet.code = CODE_PADI;
+ packet.session = 0;
+
+ if (!omit_service_name) {
+ plen = TAG_HDR_SIZE + namelen;
+ CHECK_ROOM(cursor, packet.payload, plen);
+
+ svc->type = TAG_SERVICE_NAME;
+ svc->length = htons(namelen);
+
+ if (conn->serviceName) {
+ memcpy(svc->payload, conn->serviceName, strlen(conn->serviceName));
+ }
+ cursor += namelen + TAG_HDR_SIZE;
+ } else {
+ plen = 0;
+ }
+
+ /* If we're using Host-Uniq, copy it over */
+ if (conn->hostUniq.length) {
+ int len = ntohs(conn->hostUniq.length);
+ CHECK_ROOM(cursor, packet.payload, len + TAG_HDR_SIZE);
+ memcpy(cursor, &conn->hostUniq, len + TAG_HDR_SIZE);
+ cursor += len + TAG_HDR_SIZE;
+ plen += len + TAG_HDR_SIZE;
+ }
+
+ /* Add our maximum MTU/MRU */
+ if (MIN(lcp_allowoptions[0].mru, lcp_wantoptions[0].mru) > ETH_PPPOE_MTU) {
+ PPPoETag maxPayload;
+ UINT16_t mru = htons(MIN(lcp_allowoptions[0].mru, lcp_wantoptions[0].mru));
+ maxPayload.type = htons(TAG_PPP_MAX_PAYLOAD);
+ maxPayload.length = htons(sizeof(mru));
+ memcpy(maxPayload.payload, &mru, sizeof(mru));
+ CHECK_ROOM(cursor, packet.payload, sizeof(mru) + TAG_HDR_SIZE);
+ memcpy(cursor, &maxPayload, sizeof(mru) + TAG_HDR_SIZE);
+ cursor += sizeof(mru) + TAG_HDR_SIZE;
+ plen += sizeof(mru) + TAG_HDR_SIZE;
+ }
+
+ packet.length = htons(plen);
+
+ sendPacket(conn, conn->discoverySocket, &packet, (int) (plen + HDR_SIZE));
+}
+
+/**********************************************************************
+*%FUNCTION: waitForPADO
+*%ARGUMENTS:
+* conn -- PPPoEConnection structure
+* timeout -- how long to wait (in seconds)
+*%RETURNS:
+* Nothing
+*%DESCRIPTION:
+* Waits for a PADO packet and copies useful information
+***********************************************************************/
+void
+waitForPADO(PPPoEConnection *conn, int timeout)
+{
+ fd_set readable;
+ int r;
+ struct timeval tv;
+ struct timeval expire_at;
+
+ PPPoEPacket packet;
+ int len;
+
+ struct PacketCriteria pc;
+ pc.conn = conn;
+ pc.acNameOK = (conn->acName) ? 0 : 1;
+ pc.serviceNameOK = (conn->serviceName) ? 0 : 1;
+ pc.seenACName = 0;
+ pc.seenServiceName = 0;
+ conn->seenMaxPayload = 0;
+ conn->error = 0;
+
+ if (get_time(&expire_at) < 0) {
+ error("get_time (waitForPADO): %m");
+ return;
+ }
+ expire_at.tv_sec += timeout;
+
+ do {
+ if (BPF_BUFFER_IS_EMPTY) {
+ if (!time_left(&tv, &expire_at))
+ return; /* Timed out */
+
+ FD_ZERO(&readable);
+ FD_SET(conn->discoverySocket, &readable);
+
+ while(1) {
+ r = select(conn->discoverySocket+1, &readable, NULL, NULL, &tv);
+ if (r >= 0 || errno != EINTR || got_sigterm) break;
+ }
+ if (r < 0) {
+ error("select (waitForPADO): %m");
+ return;
+ }
+ if (r == 0)
+ return; /* Timed out */
+ }
+
+ /* Get the packet */
+ receivePacket(conn->discoverySocket, &packet, &len);
+
+ /* Check length */
+ if (ntohs(packet.length) + HDR_SIZE > len) {
+ error("Bogus PPPoE length field (%u)",
+ (unsigned int) ntohs(packet.length));
+ continue;
+ }
+
+#ifdef USE_BPF
+ /* If it's not a Discovery packet, loop again */
+ if (etherType(&packet) != Eth_PPPOE_Discovery) continue;
+#endif
+
+ /* If it's not for us, loop again */
+ if (!packetIsForMe(conn, &packet)) continue;
+
+ if (packet.code == CODE_PADO) {
+ if (NOT_UNICAST(packet.ethHdr.h_source)) {
+ 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)
+ return;
+ if (!pc.seenACName) {
+ error("Ignoring PADO packet with no AC-Name tag");
+ continue;
+ }
+ if (!pc.seenServiceName) {
+ error("Ignoring PADO packet with no Service-Name tag");
+ continue;
+ }
+ conn->numPADOs++;
+ if (pc.acNameOK && pc.serviceNameOK) {
+ memcpy(conn->peerEth, packet.ethHdr.h_source, ETH_ALEN);
+ conn->discoveryState = STATE_RECEIVED_PADO;
+ break;
+ }
+ }
+ } while (conn->discoveryState != STATE_RECEIVED_PADO);
+}
+
+/***********************************************************************
+*%FUNCTION: sendPADR
+*%ARGUMENTS:
+* conn -- PPPoE connection structur
+*%RETURNS:
+* Nothing
+*%DESCRIPTION:
+* Sends a PADR packet
+***********************************************************************/
+static void
+sendPADR(PPPoEConnection *conn)
+{
+ PPPoEPacket packet;
+ PPPoETag *svc = (PPPoETag *) packet.payload;
+ unsigned char *cursor = packet.payload;
+
+ UINT16_t namelen = 0;
+ UINT16_t plen;
+
+ if (conn->serviceName) {
+ namelen = (UINT16_t) strlen(conn->serviceName);
+ }
+ plen = TAG_HDR_SIZE + namelen;
+ CHECK_ROOM(cursor, packet.payload, plen);
+
+ memcpy(packet.ethHdr.h_dest, conn->peerEth, ETH_ALEN);
+ memcpy(packet.ethHdr.h_source, conn->myEth, ETH_ALEN);
+
+ packet.ethHdr.h_proto = htons(Eth_PPPOE_Discovery);
+ packet.vertype = PPPOE_VER_TYPE(1, 1);
+ packet.code = CODE_PADR;
+ packet.session = 0;
+
+ svc->type = TAG_SERVICE_NAME;
+ svc->length = htons(namelen);
+ if (conn->serviceName) {
+ memcpy(svc->payload, conn->serviceName, namelen);
+ }
+ cursor += namelen + TAG_HDR_SIZE;
+
+ /* If we're using Host-Uniq, copy it over */
+ if (conn->hostUniq.length) {
+ int len = ntohs(conn->hostUniq.length);
+ CHECK_ROOM(cursor, packet.payload, len+TAG_HDR_SIZE);
+ memcpy(cursor, &conn->hostUniq, len + TAG_HDR_SIZE);
+ cursor += len + TAG_HDR_SIZE;
+ plen += len + TAG_HDR_SIZE;
+ }
+
+ /* Add our maximum MTU/MRU */
+ if (MIN(lcp_allowoptions[0].mru, lcp_wantoptions[0].mru) > ETH_PPPOE_MTU) {
+ PPPoETag maxPayload;
+ UINT16_t mru = htons(MIN(lcp_allowoptions[0].mru, lcp_wantoptions[0].mru));
+ maxPayload.type = htons(TAG_PPP_MAX_PAYLOAD);
+ maxPayload.length = htons(sizeof(mru));
+ memcpy(maxPayload.payload, &mru, sizeof(mru));
+ CHECK_ROOM(cursor, packet.payload, sizeof(mru) + TAG_HDR_SIZE);
+ memcpy(cursor, &maxPayload, sizeof(mru) + TAG_HDR_SIZE);
+ cursor += sizeof(mru) + TAG_HDR_SIZE;
+ plen += sizeof(mru) + TAG_HDR_SIZE;
+ }
+
+ /* Copy cookie and relay-ID if needed */
+ if (conn->cookie.type) {
+ CHECK_ROOM(cursor, packet.payload,
+ ntohs(conn->cookie.length) + TAG_HDR_SIZE);
+ memcpy(cursor, &conn->cookie, ntohs(conn->cookie.length) + TAG_HDR_SIZE);
+ cursor += ntohs(conn->cookie.length) + TAG_HDR_SIZE;
+ plen += ntohs(conn->cookie.length) + TAG_HDR_SIZE;
+ }
+
+ if (conn->relayId.type) {
+ CHECK_ROOM(cursor, packet.payload,
+ ntohs(conn->relayId.length) + TAG_HDR_SIZE);
+ memcpy(cursor, &conn->relayId, ntohs(conn->relayId.length) + TAG_HDR_SIZE);
+ cursor += ntohs(conn->relayId.length) + TAG_HDR_SIZE;
+ plen += ntohs(conn->relayId.length) + TAG_HDR_SIZE;
+ }
+
+ packet.length = htons(plen);
+ sendPacket(conn, conn->discoverySocket, &packet, (int) (plen + HDR_SIZE));
+}
+
+/**********************************************************************
+*%FUNCTION: waitForPADS
+*%ARGUMENTS:
+* conn -- PPPoE connection info
+* timeout -- how long to wait (in seconds)
+*%RETURNS:
+* Nothing
+*%DESCRIPTION:
+* Waits for a PADS packet and copies useful information
+***********************************************************************/
+static void
+waitForPADS(PPPoEConnection *conn, int timeout)
+{
+ fd_set readable;
+ int r;
+ struct timeval tv;
+ struct timeval expire_at;
+
+ PPPoEPacket packet;
+ int len;
+
+ if (get_time(&expire_at) < 0) {
+ error("get_time (waitForPADS): %m");
+ return;
+ }
+ expire_at.tv_sec += timeout;
+
+ conn->error = 0;
+ do {
+ if (BPF_BUFFER_IS_EMPTY) {
+ if (!time_left(&tv, &expire_at))
+ return; /* Timed out */
+
+ FD_ZERO(&readable);
+ FD_SET(conn->discoverySocket, &readable);
+
+ while(1) {
+ r = select(conn->discoverySocket+1, &readable, NULL, NULL, &tv);
+ if (r >= 0 || errno != EINTR || got_sigterm) break;
+ }
+ if (r < 0) {
+ error("select (waitForPADS): %m");
+ return;
+ }
+ if (r == 0)
+ return; /* Timed out */
+ }
+
+ /* Get the packet */
+ receivePacket(conn->discoverySocket, &packet, &len);
+
+ /* Check length */
+ if (ntohs(packet.length) + HDR_SIZE > len) {
+ error("Bogus PPPoE length field (%u)",
+ (unsigned int) ntohs(packet.length));
+ continue;
+ }
+
+#ifdef USE_BPF
+ /* If it's not a Discovery packet, loop again */
+ if (etherType(&packet) != Eth_PPPOE_Discovery) continue;
+#endif
+
+ /* 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;
+
+ /* Is it PADS? */
+ if (packet.code == CODE_PADS) {
+ /* Parse for goodies */
+ if (parsePacket(&packet, parsePADSTags, conn) < 0)
+ return;
+ if (conn->error)
+ return;
+ conn->discoveryState = STATE_SESSION;
+ break;
+ }
+ } while (conn->discoveryState != STATE_SESSION);
+
+ /* Don't bother with ntohs; we'll just end up converting it back... */
+ conn->session = packet.session;
+
+ info("PPP session is %d", (int) ntohs(conn->session));
+
+ /* RFC 2516 says session id MUST NOT be zero or 0xFFFF */
+ if (ntohs(conn->session) == 0 || ntohs(conn->session) == 0xFFFF) {
+ error("Access concentrator used a session value of %x -- the AC is violating RFC 2516", (unsigned int) ntohs(conn->session));
+ }
+}
+
+/**********************************************************************
+*%FUNCTION: discovery
+*%ARGUMENTS:
+* conn -- PPPoE connection info structure
+*%RETURNS:
+* Nothing
+*%DESCRIPTION:
+* Performs the PPPoE discovery phase
+***********************************************************************/
+void
+discovery(PPPoEConnection *conn)
+{
+ int padiAttempts = 0;
+ int padrAttempts = 0;
+ int timeout = conn->discoveryTimeout;
+
+ do {
+ padiAttempts++;
+ if (got_sigterm || padiAttempts > conn->discoveryAttempts) {
+ warn("Timeout waiting for PADO packets");
+ close(conn->discoverySocket);
+ conn->discoverySocket = -1;
+ return;
+ }
+ sendPADI(conn);
+ conn->discoveryState = STATE_SENT_PADI;
+ waitForPADO(conn, timeout);
+
+ timeout *= 2;
+ } while (conn->discoveryState == STATE_SENT_PADI);
+
+ timeout = conn->discoveryTimeout;
+ do {
+ padrAttempts++;
+ if (got_sigterm || padrAttempts > conn->discoveryAttempts) {
+ warn("Timeout waiting for PADS packets");
+ close(conn->discoverySocket);
+ conn->discoverySocket = -1;
+ return;
+ }
+ sendPADR(conn);
+ conn->discoveryState = STATE_SENT_PADR;
+ waitForPADS(conn, timeout);
+ timeout *= 2;
+ } while (conn->discoveryState == STATE_SENT_PADR);
+
+ if (!conn->seenMaxPayload) {
+ /* RFC 4638: MUST limit MTU/MRU to 1492 */
+ if (lcp_allowoptions[0].mru > ETH_PPPOE_MTU)
+ lcp_allowoptions[0].mru = ETH_PPPOE_MTU;
+ if (lcp_wantoptions[0].mru > ETH_PPPOE_MTU)
+ lcp_wantoptions[0].mru = ETH_PPPOE_MTU;
+ }
+
+ /* We're done. */
+ close(conn->discoverySocket);
+ conn->discoverySocket = -1;
+ conn->discoveryState = STATE_SESSION;
+ return;
+}
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