pppoe server for linux

/*********************************************************************** * * pppoe-server.c * * Implementation of a user-space PPPoE server * * Copyright (C) 2000 Roaring Penguin Software Inc. * * This program may be distributed according to the terms of the GNU * General Public License, version 2 or (at your option) any later version. * * $Id: pppoe-server.c,v 1.91 2005/08/10 00:25:21 dfs Exp $ * * LIC: GPL * ***********************************************************************/ static char const RCSID[] = "$Id: pppoe-server.c,v 1.91 2005/08/10 00:25:21 dfs Exp $"; #include "config.h" #if defined(HAVE_NETPACKET_PACKET_H) || defined(HAVE_LINUX_IF_PACKET_H) #define _POSIX_SOURCE 1 /* For sigaction defines */ #endif #define _BSD_SOURCE 1 /* for gethostname */ #include "pppoe-server.h" #include "md5.h" #ifdef HAVE_SYSLOG_H #include <syslog.h> #endif #include <errno.h> #include <string.h> #include <stdlib.h> #include <fcntl.h> #ifdef HAVE_UNISTD_H #include <unistd.h> #endif #ifdef HAVE_GETOPT_H #include <getopt.h> #endif #ifdef HAVE_SYS_WAIT_H #include <sys/wait.h> #endif #ifdef HAVE_SYS_TIME_H #include <sys/time.h> #endif #include <time.h> #include <signal.h> #ifdef HAVE_LICENSE #include "license.h" #include "licensed-only/servfuncs.h" static struct License const *ServerLicense; static struct License const *ClusterLicense; #else #define control_session_started(x) (void) 0 #define control_session_terminated(x) (void) 0 #define control_exit() (void) 0 #define realpeerip peerip #endif #ifdef HAVE_L2TP extern PppoeSessionFunctionTable L2TPSessionFunctionTable; extern void pppoe_to_l2tp_add_interface(EventSelector *es, Interface *interface); #endif static void InterfaceHandler(EventSelector *es, int fd, unsigned int flags, void *data); static void startPPPD(ClientSession *sess); static void sendErrorPADS(int sock, unsigned char *source, unsigned char *dest, int errorTag, char *errorMsg); #define CHECK_ROOM(cursor, start, len) \ do {\ if (((cursor)-(start))+(len) > MAX_PPPOE_PAYLOAD) { \ syslog(LOG_ERR, "Would create too-long packet"); \ return; \ } \ } while(0) static void PppoeStopSession(ClientSession *ses, char const *reason); static int PppoeSessionIsActive(ClientSession *ses); /* Service-Names we advertise */ #define MAX_SERVICE_NAMES 64 static int NumServiceNames = 0; static char const *ServiceNames[MAX_SERVICE_NAMES]; PppoeSessionFunctionTable DefaultSessionFunctionTable = { PppoeStopSession, PppoeSessionIsActive, NULL }; /* An array of client sessions */ ClientSession *Sessions = NULL; ClientSession *FreeSessions = NULL; ClientSession *LastFreeSession = NULL; ClientSession *BusySessions = NULL; /* Interfaces we're listening on */ Interface interfaces[MAX_INTERFACES]; int NumInterfaces = 0; /* The number of session slots */ size_t NumSessionSlots; /* Number of active sessions */ size_t NumActiveSessions = 0; /* Offset of first session */ size_t SessOffset = 0; /* Event Selector */ EventSelector *event_selector; /* Use Linux kernel-mode PPPoE? */ static int UseLinuxKernelModePPPoE = 0; static int Debug = 0; static int CheckPoolSyntax = 0; /* Synchronous mode */ static int Synchronous = 0; /* Random seed for cookie generation */ #define SEED_LEN 16 #define MD5_LEN 16 #define COOKIE_LEN (MD5_LEN + sizeof(pid_t)) /* Cookie is 16-byte MD5 + PID of server */ static unsigned char CookieSeed[SEED_LEN]; #define MAXLINE 512 /* Default interface if no -I option given */ #define DEFAULT_IF "eth0" /* Access concentrator name */ char *ACName = NULL; /* Options to pass to pppoe process */ char PppoeOptions[SMALLBUF] = ""; /* Our local IP address */ unsigned char LocalIP[IPV4ALEN] = {10, 0, 0, 1}; /* Counter optionally STARTS here */ unsigned char RemoteIP[IPV4ALEN] = {10, 67, 15, 1}; /* Counter STARTS here */ /* Do we increment local IP for each connection? */ int IncrLocalIP = 0; /* Do we randomize session numbers? */ int RandomizeSessionNumbers = 0; /* Do we pass the "unit" option to pppd? (2.4 or greater) */ int PassUnitOptionToPPPD = 0; static PPPoETag hostUniq; static PPPoETag relayId; static PPPoETag receivedCookie; static PPPoETag requestedService; #define HOSTNAMELEN 256 /********************************************************************** *%FUNCTION: childHandler *%ARGUMENTS: * pid -- pid of child * status -- exit status * ses -- which session terminated *%RETURNS: * Nothing *%DESCRIPTION: * Called synchronously when a child dies. Remove from busy list. ***********************************************************************/ static void childHandler(pid_t pid, int status, void *s) { ClientSession *session = s; /* Temporary structure for sending PADT's. */ PPPoEConnection conn; #ifdef HAVE_L2TP /* We're acting as LAC, so when child exits, become a PPPoE <-> L2TP relay */ if (session->flags & FLAG_ACT_AS_LAC) { syslog(LOG_INFO, "Session %d for client " "%02x:%02x:%02x:%02x:%02x:%02x handed off to LNS %s", ntohs(session->sess), session->eth[0], session->eth[1], session->eth[2], session->eth[3], session->eth[4], session->eth[5], inet_ntoa(session->tunnel_endpoint.sin_addr)); session->pid = 0; session->funcs = &L2TPSessionFunctionTable; return; } #endif memset(&conn, 0, sizeof(conn)); conn.useHostUniq = 0; syslog(LOG_INFO, "Session %d closed for client " "%02x:%02x:%02x:%02x:%02x:%02x (%d.%d.%d.%d) on %s", ntohs(session->sess), session->eth[0], session->eth[1], session->eth[2], session->eth[3], session->eth[4], session->eth[5], (int) session->realpeerip[0], (int) session->realpeerip[1], (int) session->realpeerip[2], (int) session->realpeerip[3], session->ethif->name); memcpy(conn.myEth, session->ethif->mac, ETH_ALEN); conn.discoverySocket = session->ethif->sock; conn.session = session->sess; memcpy(conn.peerEth, session->eth, ETH_ALEN); if (!(session->flags & FLAG_SENT_PADT)) { if (session->flags & FLAG_RECVD_PADT) { sendPADT(&conn, "RP-PPPoE: Received PADT from peer"); } else { sendPADT(&conn, "RP-PPPoE: Child pppd process terminated"); } session->flags |= FLAG_SENT_PADT; } session->serviceName = ""; control_session_terminated(session); if (pppoe_free_session(session) < 0) { return; } } /********************************************************************** *%FUNCTION: incrementIPAddress (static) *%ARGUMENTS: * addr -- a 4-byte array representing IP address *%RETURNS: * Nothing *%DESCRIPTION: * Increments addr in-place ***********************************************************************/ static void incrementIPAddress(unsigned char ip[IPV4ALEN]) { ip[3]++; if (!ip[3]) { ip[2]++; if (!ip[2]) { ip[1]++; if (!ip[1]) { ip[0]++; } } } } /********************************************************************** *%FUNCTION: killAllSessions *%ARGUMENTS: * None *%RETURNS: * Nothing *%DESCRIPTION: * Kills all pppd processes (and hence all PPPoE sessions) ***********************************************************************/ void killAllSessions(void) { ClientSession *sess = BusySessions; while(sess) { sess->funcs->stop(sess, "Shutting Down"); sess = sess->next; } #ifdef HAVE_L2TP pppoe_close_l2tp_tunnels(); #endif } /********************************************************************** *%FUNCTION: parseAddressPool *%ARGUMENTS: * fname -- name of file containing IP address pool. * install -- if true, install IP addresses in sessions. *%RETURNS: * Number of valid IP addresses found. *%DESCRIPTION: * Reads a list of IP addresses from a file. ***********************************************************************/ static int parseAddressPool(char const *fname, int install) { FILE *fp = fopen(fname, "r"); int numAddrs = 0; unsigned int a, b, c, d; unsigned int e, f, g, h; char line[MAXLINE]; if (!fp) { sysErr("Cannot open address pool f