/*
* Perform PPPoE discovery
*
* Copyright (C) 2000-2001 by Roaring Penguin Software Inc.
* Copyright (C) 2004 Marco d'Itri <md@linux.it>
*
* This program may be distributed according to the terms of the GNU
* General Public License, version 2 or (at your option) any later version.
*
*/
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include "pppoe.h"
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#ifdef HAVE_NETPACKET_PACKET_H
#include <netpacket/packet.h>
#elif defined(HAVE_LINUX_IF_PACKET_H)
#include <linux/if_packet.h>
#endif
#ifdef HAVE_NET_ETHERNET_H
#include <net/ethernet.h>
#endif
#ifdef HAVE_ASM_TYPES_H
#include <asm/types.h>
#endif
#ifdef HAVE_SYS_IOCTL_H
#include <sys/ioctl.h>
#endif
#include <errno.h>
#include <stdlib.h>
#include <string.h>
#ifdef HAVE_NET_IF_ARP_H
#include <net/if_arp.h>
#endif
char *xstrdup(const char *s);
void usage(void);
void die(int status)
{
exit(status);
}
/* Initialize frame types to RFC 2516 values. Some broken peers apparently
use different frame types... sigh... */
UINT16_t Eth_PPPOE_Discovery = ETH_PPPOE_DISCOVERY;
UINT16_t Eth_PPPOE_Session = ETH_PPPOE_SESSION;
/**********************************************************************
*%FUNCTION: etherType
*%ARGUMENTS:
* packet -- a received PPPoE packet
*%RETURNS:
* ethernet packet type (see /usr/include/net/ethertypes.h)
*%DESCRIPTION:
* Checks the ethernet packet header to determine its type.
* We should only be receveing DISCOVERY and SESSION types if the BPF
* is set up correctly. Logs an error if an unexpected type is received.
* Note that the ethernet type names come from "pppoe.h" and the packet
* packet structure names use the LINUX dialect to maintain consistency
* with the rest of this file. See the BSD section of "pppoe.h" for
* translations of the data structure names.
***********************************************************************/
UINT16_t
etherType(PPPoEPacket *packet)
{
UINT16_t type = (UINT16_t) ntohs(packet->ethHdr.h_proto);
if (type != Eth_PPPOE_Discovery && type != Eth_PPPOE_Session) {
fprintf(stderr, "Invalid ether type 0x%x\n", type);
}
return type;
}
/**********************************************************************
*%FUNCTION: openInterface
*%ARGUMENTS:
* ifname -- name of interface
* type -- Ethernet frame type
* hwaddr -- if non-NULL, set to the hardware address
*%RETURNS:
* A raw socket for talking to the Ethernet card. Exits on error.
*%DESCRIPTION:
* Opens a raw Ethernet socket
***********************************************************************/
int
openInterface(char const *ifname, UINT16_t type, unsigned char *hwaddr)
{
int optval=1;
int fd;
struct ifreq ifr;
int domain, stype;
#ifdef HAVE_STRUCT_SOCKADDR_LL
struct sockaddr_ll sa;
#else
struct sockaddr sa;
#endif
memset(&sa, 0, sizeof(sa));
#ifdef HAVE_STRUCT_SOCKADDR_LL
domain = PF_PACKET;
stype = SOCK_RAW;
#else
domain = PF_INET;
stype = SOCK_PACKET;
#endif
if ((fd = socket(domain, stype, htons(type))) < 0) {
/* Give a more helpful message for the common error case */
if (errno == EPERM) {
rp_fatal("Cannot create raw socket -- pppoe must be run as root.");
}
fatalSys("socket");
}
if (setsockopt(fd, SOL_SOCKET, SO_BROADCAST, &optval, sizeof(optval)) < 0) {
fatalSys("setsockopt");
}
/* Fill in hardware address */
if (hwaddr) {
strncpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name));
if (ioctl(fd, SIOCGIFHWADDR, &ifr) < 0) {
fatalSys("ioctl(SIOCGIFHWADDR)");
}
memcpy(hwaddr, ifr.ifr_hwaddr.sa_data, ETH_ALEN);
#ifdef ARPHRD_ETHER
if (ifr.ifr_hwaddr.sa_family != ARPHRD_ETHER) {
char buffer[256];
sprintf(buffer, "Interface %.16s is not Ethernet", ifname);
rp_fatal(buffer);
}
#endif
if (NOT_UNICAST(hwaddr)) {
char buffer[256];
sprintf(buffer,
"Interface %.16s has broadcast/multicast MAC address??",
ifname);
rp_fatal(buffer);
}
}
/* Sanity check on MTU */
strncpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name));
if (ioctl(fd, SIOCGIFMTU, &ifr) < 0) {
fatalSys("ioctl(SIOCGIFMTU)");
}
if (ifr.ifr_mtu < ETH_DATA_LEN) {
fprintf(stderr, "Interface %.16s has MTU of %d -- should be %d.\n",
ifname, ifr.ifr_mtu, ETH_DATA_LEN);
fprintf(stderr, "You may have serious connection problems.\n");
}
#ifdef HAVE_STRUCT_SOCKADDR_LL
/* Get interface index */
sa.sll_family = AF_PACKET;
sa.sll_protocol = htons(type);
strncpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name));
if (ioctl(fd, SIOCGIFINDEX, &ifr) < 0) {
fatalSys("ioctl(SIOCFIGINDEX): Could not get interface index");
}
sa.sll_ifindex = ifr.ifr_ifindex;
#else
strcpy(sa.sa_data, ifname);
#endif
/* We're only interested in packets on specified interface */
if (bind(fd, (struct sockaddr *) &sa, sizeof(sa)) < 0) {
fatalSys("bind");
}
return fd;
}
/***********************************************************************
*%FUNCTION: sendPacket
*%ARGUMENTS:
* sock -- socket to send to
* pkt -- the packet to transmit
* size -- size of packet (in bytes)
*%RETURNS:
* 0 on success; -1 on failure
*%DESCRIPTION:
* Transmits a packet
***********************************************************************/
int
sendPacket(PPPoEConnection *conn, int sock, PPPoEPacket *pkt, int size)
{
#if defined(HAVE_STRUCT_SOCKADDR_LL)
if (send(sock, pkt, size, 0) < 0) {
sysErr("send (sendPacket)");
return -1;
}
#else
struct sockaddr sa;
if (!conn) {
rp_fatal("relay and server not supported on Linux 2.0 kernels");
}
strcpy(sa.sa_data, conn->ifName);
if (sendto(sock, pkt, size, 0, &sa, sizeof(sa)) < 0) {
sysErr("sendto (sendPacket)");
return -1;
}
#endif
return 0;
}
/***********************************************************************
*%FUNCTION: receivePacket
*%ARGUMENTS:
* sock -- socket to read from
* pkt -- place to store the received packet
* size -- set to size of packet in bytes
*%RETURNS:
* >= 0 if all OK; < 0 if error
*%DESCRIPTION:
* Receives a packet
***********************************************************************/
int
receivePacket(int sock, PPPoEPacket *pkt, int *size)
{
if ((*size = recv(sock, pkt, sizeof(PPPoEPacket), 0)) < 0) {
sysErr("recv (receivePacket)");
return -1;
}
return 0;
}
/**********************************************************************
*%FUNCTION: parsePacket
*%ARGUMENTS:
* packet -- the PPPoE discovery packet to parse
* func -- function called for each tag in the packet
* extra -- an opaque data pointer supplied to parsing function
*%RETURNS:
* 0 if everything went well; -1 if there was an error
*%DESCRIPTION:
* Parses a PPPoE discovery packet, calling "func" for each tag in the packet.
* "func" is passed the additional argument "extra".
***********************************************************************/
int
parsePacket(PPPoEPacket *packet, ParseFunc *func, void *extra)
{
UINT16_t len = ntohs(packet->length);
unsigned char *curTag;
UINT16_t tagType, tagLen;
if (PPPOE_VER(packet->vertype) != 1) {
fprintf(stderr, "Invalid PPPoE version (%d)\n",
PPPOE_VER(packet->vertype));
return -1;
}
if (PPPOE_TYPE(packet->vertype) != 1) {
fprintf(stderr, "Invalid PPPoE type (%d)\n",
PPPOE_TYPE(packet->vertype));
return -1;
}
/* Do some sanity checks on packet */
if (len > ETH_JUMBO_LEN - PPPOE_OVERHEAD) { /* 6-byte overhead for PPPoE header */
fprintf(stderr, "Invalid PPPoE packet length (%u)\n", len);
return -1;
}
/* Step through the tags */
curTag = packet->payload;
while(curTag - packet->payload < len) {
/* Alignment is not guaranteed, so do this by hand... */
tagType = (curTag[0] << 8) + curTag[1];
tagLen = (curTag[2] << 8) + curTag[3];
if (tagType == TAG_END_OF_LIST) {
return 0;
}
if ((curTag - packet->payload) + tagLen + TAG_HDR_SIZE > len) {
fprintf(stderr, "Invalid PPPoE tag length (%u)\n", tagLen);
return -1;
}
func(tagType, tagLen, curTag+TAG_HDR_SIZE, extra);
curTag = curTag + TAG_HDR_SIZE + tagLen;
}
return 0;
}
/**********************************************************************
*%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.
***********************************************************************/
void
parseForHostUniq(UINT16_t type, UINT16_t len, unsigned char *data,
void *extra)
{
int *val = (int *) extra;
if (type == TAG_HOST_UNIQ && len == sizeof(pid_t)) {
pid_t tmp;
memcpy(&tmp, data, len);
if (tmp == getpid()) {
*val = 1;
}
}
}
/**********************************************************************
*%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.
***********************************************************************/
int
packetIsForMe(PPPoEConnection *conn, PPPoEPacket *packet)
{
int forMe = 0;
/* 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;
parsePacket(packet, parseForHostUniq, &forMe);
return forMe;
}
/**********************************************************************
*%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
***********************************************************************/
void
parsePADOTags(UINT16_t type, UINT16_t len, unsigned char *data,
void *extra)
{
struct PacketCriteria *pc = (struct PacketCriteria *) extra;
PPPoEConnection *conn = pc->conn;
int i;
switch(type) {
case TAG_AC_NAME:
pc->seenACName = 1;
printf("Access-Concentrator: %.*s\n", (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 (len > 0) {
printf(" Service-Name: %.*s\n", (int) len, data);
}
if (conn->serviceName && len == strlen(conn->serviceName) &&
!strncmp((char *) data, conn->serviceName, len)) {
pc->serviceNameOK = 1;
}
break;
case TAG_AC_COOKIE:
printf("Got a cookie:");
/* Print first 20 bytes of cookie */
for (i=0; i<len && i < 20; i++) {
printf(" %02x", (unsigned) data[i]);
}
if (i < len) printf("...");
printf("\n");
conn->cookie.type = htons(type);
conn->cookie.length = htons(len);
memcpy(conn->cookie.payload, data, len);
break;
case TAG_RELAY_SESSION_ID:
printf("Got a Relay-ID:");
/* Print first 20 bytes of relay ID */
for (i=0; i<len && i < 20; i++) {
printf(" %02x", (unsigned) data[i]);
}
if (i < len) printf("...");
printf("\n");
conn->relayId.type = htons(type);
conn->relayId.length = htons(len);
memcpy(conn->relayId.payload, data, len);
break;
case TAG_SERVICE_NAME_ERROR:
printf("Got a Service-Name-Error tag: %.*s\n", (int) len, data);
break;
case TAG_AC_SYSTEM_ERROR:
printf("Got a System-Error tag: %.*s\n", (int) len, data);
break;
case TAG_GENERIC_ERROR:
printf("Got a Generic-Error tag: %.*s\n", (int) len, data);
break;
}
}
/***********************************************************************
*%FUNCTION: sendPADI
*%ARGUMENTS:
* conn -- PPPoEConnection structure
*%RETURNS:
* Nothing
*%DESCRIPTION:
* Sends a PADI packet
***********************************************************************/
void
sendPADI(PPPoEConnection *conn)
{
PPPoEPacket packet;
unsigned char *cursor = packet.payload;
PPPoETag *svc = (PPPoETag *) (&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);
/* 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;
svc->type = TAG_SERVICE_NAME;
svc->length = htons(namelen);
CHECK_ROOM(cursor, packet.payload, namelen+TAG_HDR_SIZE);
if (conn->serviceName) {
memcpy(svc->payload, conn->serviceName, strlen(conn->serviceName));
}
cursor += namelen + TAG_HDR_SIZE;
/* If we're using Host-Uniq, copy it over */
if (conn->useHostUniq) {
PPPoETag hostUniq;
pid_t pid = getpid();
hostUniq.type = htons(TAG_HOST_UNIQ);
hostUniq.length = htons(sizeof(pid));
memcpy(hostUniq.payload, &pid, sizeof(pid));
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);
sendPacket(conn, conn->discoverySocket, &packet, (int) (plen + HDR_SIZE));
if (conn->debugFile) {
dumpPacket(conn->debugFile, &packet, "SENT");
fprintf(conn->debugFile, "\n");
fflush(conn->debugFile);
}
}
/**********************************************************************
*%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;
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->error = 0;
do {
if (BPF_BUFFER_IS_EMPTY) {
tv.tv_sec = timeout;
tv.tv_usec = 0;
FD_ZERO(&readable);
FD_SET(conn->discoverySocket, &readable);
while(1) {
r = select(conn->discoverySocket+1, &readable, NULL, NULL, &tv);
if (r >= 0 || errno != EINTR) break;
}
if (r < 0) {
perror("select (waitForPADO)");
return;
}
if (r == 0) return; /* Timed out */
}
/* Get the packet */
receivePacket(conn->discoverySocket, &packet, &len);
/* Check length */
if (ntohs(packet.length) + HDR_SIZE > len) {
fprintf(stderr, "Bogus PPPoE length field (%u)\n",
(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 (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 (packet.code == CODE_PADO) {
if (BROADCAST(packet.ethHdr.h_source)) {
fprintf(stderr, "Ignoring PADO packet from broadcast MAC address\n");
continue;
}
parsePacket(&packet, parsePADOTags, &pc);
if (conn->error)
return;
if (!pc.seenACName) {
fprintf(stderr, "Ignoring PADO packet with no AC-Name tag\n");
continue;
}
if (!pc.seenServiceName) {
fprintf(stderr, "Ignoring PADO packet with no Service-Name tag\n");
continue;
}
conn->numPADOs++;
printf("--------------------------------------------------\n");
if (pc.acNameOK && pc.serviceNameOK) {
memcpy(conn->peerEth, packet.ethHdr.h_source, ETH_ALEN);
if (conn->printACNames) {
printf("AC-Ethernet-Address: %02x:%02x:%02x:%02x:%02x:%02x\n",
(unsigned) conn->peerEth[0],
(unsigned) conn->peerEth[1],
(unsigned) conn->peerEth[2],
(unsigned) conn->peerEth[3],
(unsigned) conn->peerEth[4],
(unsigned) conn->peerEth[5]);
continue;
}
conn->discoveryState = STATE_RECEIVED_PADO;
break;
}
}
} while (conn->discoveryState != STATE_RECEIVED_PADO);
}
/**********************************************************************
*%FUNCTION: discovery
*%ARGUMENTS:
* conn -- PPPoE connection info structure
*%RETURNS:
* Nothing
*%DESCRIPTION:
* Performs the PPPoE discovery phase
***********************************************************************/
void
discovery(PPPoEConnection *conn)
{
int padiAttempts = 0;
int timeout = PADI_TIMEOUT;
conn->discoverySocket =
openInterface(conn->ifName, Eth_PPPOE_Discovery, conn->myEth);
do {
padiAttempts++;
if (padiAttempts > MAX_PADI_ATTEMPTS) {
fprintf(stderr, "Timeout waiting for PADO packets\n");
close(conn->discoverySocket);
conn->discoverySocket = -1;
return;
}
sendPADI(conn);
conn->discoveryState = STATE_SENT_PADI;
waitForPADO(conn, timeout);
} while (!conn->numPADOs);
}
int main(int argc, char *argv[])
{
int opt;
PPPoEConnection *conn;
conn = malloc(sizeof(PPPoEConnection));
if (!conn)
fatalSys("malloc");
memset(conn, 0, sizeof(PPPoEConnection));
while ((opt = getopt(argc, argv, "I:D:VUAS:C:h")) > 0) {
switch(opt) {
case 'S':
conn->serviceName = xstrdup(optarg);
break;
case 'C':
conn->acName = xstrdup(optarg);
break;
case 'U':
conn->useHostUniq = 1;
break;
case 'D':
conn->debugFile = fopen(optarg, "w");
if (!conn->debugFile) {
fprintf(stderr, "Could not open %s: %s\n",
optarg, strerror(errno));
exit(1);
}
fprintf(conn->debugFile, "pppoe-discovery %s\n", RP_VERSION);
break;
case 'I':
conn->ifName = xstrdup(optarg);
break;
case 'A':
/* this is the default */
break;
case 'V':
case 'h':
usage();
exit(0);
default:
usage();
exit(1);
}
}
/* default interface name */
if (!conn->ifName)
conn->ifName = strdup("eth0");
conn->discoverySocket = -1;
conn->sessionSocket = -1;
conn->printACNames = 1;
discovery(conn);
exit(0);
}
void rp_fatal(char const *str)
{
fprintf(stderr, "%s\n", str);
exit(1);
}
void fatalSys(char const *str)
{
perror(str);
exit(1);
}
void sysErr(char const *str)
{
rp_fatal(str);
}
char *xstrdup(const char *s)
{
register char *ret = strdup(s);
if (!ret)
sysErr("strdup");
return ret;
}
void usage(void)
{
fprintf(stderr, "Usage: pppoe-discovery [options]\n");
fprintf(stderr, "\nVersion " RP_VERSION "\n");
}