heartbeat/0000775000175200017530000000000007740143766006603 5heartbeat/client/0000775000175200017530000000000007740143777010063 5heartbeat/client/heartbeat.conf0000664000175200017530000000252207740143743012603 # Configuration for SixXS Heartbeat Client # SixXS - http://www.sixxs.net # Operating System (linux/freebsd/openbsd/netbsd/winxp) os linux # Interface the tunnel should go over # used for detecting the local IPv4 endpoint ipv4_interface eth0 # IPv4 address of the POP (nlams01/nlams02/nlams04/demun01/iedub01/dkcop01) # This is also the address to which heartbeats # are sent ipv4_pop [POP].sixxs.net # ipv4_local is figured out automatically # from the ipv4_interface # Special case for people having their # endpoint behind a NAT # # Don't change the local tunnel endpoint #hb_statictunnel 1 # # The hostname or IP of the 'external' IP # from which the heartbeat should originate #ipv4_local_resolve public-ip.example.net # Interface to be used for the tunnel # will be created on the OS's that need that ipv6_interface sixxs # The local and remote sides of the tunnel ipv6_pop 2001:db8::1 ipv6_local 2001:db8::2 # The prefix length of the tunnel # Tunnel space is thus ipv6_pop/ipv6_prefixlen ipv6_prefixlen 64 # The Heartbeat password for this tunnel hb_password hartslag # The interval at which to send the heartbeat hb_sendinterval 60 # Informational: after this timeout the tunnel # is taken down at the POP side hb_timeout 300 # Put the client in the background? (default) # Set to 0 to keep in foreground, eg for daemontools # daemonize 1 heartbeat/client/Makefile0000664000175200017530000000047007740143743011435 SRCS = heartbeat-client.c ../common/md5.c OBJS = heartbeat-client.o ../common/md5.o CFLAGS = -W -Wall -Wno-unused -D_GNU_SOURCE -g -O2 LDFLAGS = CC = gcc RM = rm all: heartbeat-client heartbeat-client: $(OBJS) $(CC) -g -o $@ $(OBJS) $(LDFLAGS); strip $@ clean: $(RM) -f $(OBJS) heartbeat-client heartbeat/client/heartbeat-client.c0000664000175200017530000002312707740143743013360 /************************************** SixXS Heartbeat Client by Jeroen Massar *************************************** $Author: jeroen $ $Id: heartbeat-client.c,v 1.7 2003/10/06 00:51:31 jeroen Exp $ $Date: 2003/10/06 00:51:31 $ **************************************/ #define _XOPEN_SOURCE #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "../common/config.h" // Config int g_os = -1; char *g_ipv4_interface = NULL; char *g_ipv4_pop = NULL; char *g_ipv4_local = NULL; char *g_ipv4_local_resolve = NULL; char *g_ipv6_interface = NULL; char *g_ipv6_pop = NULL; char *g_ipv6_local = NULL; int g_ipv6_prefixlen = 0; char *g_password = NULL; int g_sendinterval = 60; int g_timeout = 300; int g_statictunnel = 0; int g_daemonize = 1; #define CONF_STRING 1 #define CONF_INT 2 enum { OS_WINXP = 42, OS_LINUX, OS_FREEBSD, OS_OPENBSD, OS_NETBSD }; struct os { char *label; int val; } os[] = { {"winxp", OS_WINXP }, {"linux", OS_LINUX }, {"freebsd", OS_FREEBSD }, {"openbsd", OS_OPENBSD }, {"netbsd", OS_NETBSD }, {NULL, OS_WINXP }, }; struct conf { char *label; int type; void *var; } conf[] = { {"ipv4_interface", CONF_STRING, &g_ipv4_interface}, {"ipv4_pop", CONF_STRING, &g_ipv4_pop}, {"ipv4_local_resolve", CONF_STRING, &g_ipv4_local_resolve}, {"ipv6_interface", CONF_STRING, &g_ipv6_interface}, {"ipv6_pop", CONF_STRING, &g_ipv6_pop}, {"ipv6_local", CONF_STRING, &g_ipv6_local}, {"ipv6_prefixlen", CONF_INT, &g_ipv6_prefixlen}, {"hb_password", CONF_STRING, &g_password}, {"hb_sendinterval", CONF_INT, &g_sendinterval}, {"hb_timeout", CONF_INT, &g_timeout}, {"hb_statictunnel", CONF_INT, &g_statictunnel}, {"daemonize", CONF_INT, &g_daemonize}, {NULL, CONF_INT, NULL}, }; /************************************** Functions **************************************/ void hblog(int level, char *fmt, ...) { va_list ap; va_start(ap, fmt); if (g_daemonize) vsyslog(LOG_LOCAL7|level, fmt, ap); else vprintf(fmt, ap); va_end(ap); } // Change the local endpoint of this tunnel void tunnel_change() { char buf[1000]; char *cmd; // Don't touch the tunnel // In this mode the client can be run as non-root btw if (g_statictunnel != 0) return; hblog(LOG_INFO, "IP address change to %s detected, reconfiguring\n", g_ipv4_local); buf[0] = '\0'; switch (g_os) { case OS_LINUX: cmd = "ip tunnel change %s local %s"; break; case OS_FREEBSD: cmd = "gifconfig %s %s %s"; break; case OS_OPENBSD: cmd = "ifconfig %s giftunnel %s %s"; break; case OS_NETBSD: cmd = "ifconfig %s tunnel %s %s"; break; case OS_WINXP: cmd = "netsh interface ipv6 add v6v4tunnel %s %s %s"; break; default: hblog(LOG_ERR, "Unknown OS while changing endpoint.\n"); hblog(LOG_ERR, "Exiting...\n"); exit(-1); } snprintf(buf, sizeof(buf), cmd, g_ipv6_interface, g_ipv4_local, g_ipv4_pop); system(buf); } // configure this client int loadconfig(char *filename) { FILE *f; char buf[1000], *p; unsigned int line = 0, i, len, found; struct conf *c; struct os *o; f = fopen(filename, "r"); if (!f) { fprintf(stderr, "Could not open config file \"%s\"\n", filename); return -1; } while (fgets(buf, sizeof(buf), f)) { line++; /* chop off \n and \r */ if ((p = strchr (buf, '\n'))) *p = '\0'; if ((p = strchr (buf, '\r'))) *p = '\0'; /* Ignore comments and emtpy lines */ if ( buf[0] == '#' || buf[0] == ';' || buf[0] == ' ' || strlen(buf) < 1) continue; found = 0; if (strncasecmp(buf, "os ", 3) == 0) { o = os; while (o->label != NULL) { if (strcasecmp(&buf[3], o->label) == 0) { g_os = o->val; break; } o++; } if (g_os == -1) fprintf(stderr, "Unknown OS \"%s\"\n", &buf[3]); continue; } c = conf; while (c->label != NULL) { len = strlen(c->label); if (strncasecmp(buf, c->label, len) == 0) { if (c->type == CONF_STRING) { char **str = (char **)c->var; *str = strdup(&buf[len+1]); } else if (c->type == CONF_INT) { sscanf(&buf[len+1], "%d", (int *)c->var); } found = 1; break; } c++; } if (found == 0) fprintf(stderr, "Unknown configuration statement: %s\n", buf); } fclose(f); // Is OS not set? if (g_os == -1) { fprintf(stderr, "Required parameter \"os\" not set\n"); return -1; } return 1; } int heartbeat_socket() { int sockfd; struct sockaddr sa; socklen_t socklen; char local_ipv4[NI_MAXHOST]; #if defined(SOL_SOCKET) && defined(SO_BINDTODEVICE) struct ifreq interface; #endif struct addrinfo hints, *res, *ressave; // Get ourselves a nice IPv4 socket sockfd = socket(AF_INET, SOCK_DGRAM, 0); if (sockfd < 0) return -1; #if defined(SOL_SOCKET) && defined(SO_BINDTODEVICE) // We don't have to bind to a device if this // is a static tunnel, this allows running // the heartbeat client as non-root. if (!g_statictunnel) { // Only allowed as root, but we need root rights anyways // to (re)configure the tunnel // Bind to the underlying IPv4 device memset(&interface, 0, sizeof(interface)); strncpy(interface.ifr_ifrn.ifrn_name, g_ipv4_interface, IFNAMSIZ); if (setsockopt(sockfd, SOL_SOCKET, SO_BINDTODEVICE, (char *)&interface, sizeof(interface)) == -1) { hblog(LOG_ERR, "Couldn't bind to device \"%s\"\n", g_ipv4_interface); hblog(LOG_ERR, "Exiting...\n"); close(sockfd); exit(-1); } } #endif // connect to the remote port // this causes us to be able to use normal write() // and also gives us the ability to find out the local IP memset(&hints, 0, sizeof(struct addrinfo)); hints.ai_family = AF_INET; hints.ai_socktype = SOCK_DGRAM; // Get the POP IPv4 into a sockaddr if (getaddrinfo(g_ipv4_pop, PORT, &hints, &res) < 0) { hblog(LOG_ERR, "Couldn't resolve POP ip %s\n", g_ipv4_pop); hblog(LOG_ERR, "Exiting...\n"); close(sockfd); exit(-1); } ressave = res; while (res) { if (connect(sockfd, res->ai_addr, res->ai_addrlen) == 0) break; res = res->ai_next; } freeaddrinfo(ressave); if (res == NULL) { hblog(LOG_ERR, "Failed to connect() to remote side\n"); close(sockfd); exit(-1); } // Normal operation, find out our local IPv4 address if (g_ipv4_local_resolve == NULL) { // Figure out our local IP socklen = sizeof(sa); if (getsockname(sockfd, &sa, &socklen) == -1) { hblog(LOG_WARNING, "Couldn't get local socketaddress\n"); close(sockfd); return -1; } if (getnameinfo((struct sockaddr *)&sa, sizeof(sa), local_ipv4, sizeof(local_ipv4), NULL, 0, NI_NUMERICHOST) != 0) { hblog(LOG_WARNING, "Couldn't get local IP\n"); close(sockfd); return -1; } } else { // this causes us to be able to use normal write() // and also gives us the ability to find out the local IP memset(&hints, 0, sizeof(struct addrinfo)); hints.ai_family = AF_INET; hints.ai_socktype = SOCK_DGRAM; // Get the POP IPv4 into a sockaddr if (getaddrinfo(g_ipv4_local_resolve, NULL, &hints, &res) < 0) { hblog(LOG_ERR, "Couldn't resolve POP ip %s\n", g_ipv4_pop); hblog(LOG_ERR, "Exiting...\n"); close(sockfd); exit(-1); } ressave = res; while (res) { if (getnameinfo(res->ai_addr, res->ai_addrlen, local_ipv4, sizeof(local_ipv4), NULL, 0, NI_NUMERICHOST) == 0) { break; } hblog(LOG_WARNING, "Couldn't get local IP\n"); res = res->ai_next; } freeaddrinfo(ressave); } // Did the IPv4 address change? if (g_ipv4_local == NULL || strcmp(g_ipv4_local, local_ipv4) != 0) { if (g_ipv4_local) free(g_ipv4_local); g_ipv4_local = strdup(local_ipv4); // Run a script to change the address tunnel_change(); } // Return it return sockfd; } int sendhb(int sockfd) { struct MD5Context md5; unsigned char *p, our_digest[16], *pn = our_digest, buf[1000]; time_t time_tee; struct tm tm; int i; time_tee = time(NULL); // Create the string to send including our password snprintf(buf, sizeof(buf), "HEARTBEAT TUNNEL %s %s %ld %s", g_ipv6_local, g_ipv4_local, time_tee, g_password); // Generate a MD5 MD5Init(&md5); MD5Update(&md5, buf, strlen(buf)); MD5Final(our_digest, &md5); // Overwrite it without password p = buf; p += snprintf(buf, sizeof(buf)-17, "HEARTBEAT TUNNEL %s %s %ld ", g_ipv6_local, g_ipv4_local, time_tee); // append the digest for (i = 0; i < 16; i++) { sprintf(p, "%02x", *pn++); p+=2; } *p = '\0'; // Send the heartbeat write(sockfd, buf, strlen(buf)); hblog(LOG_DEBUG, "[HB] %s\n", buf); return 0; } void beat() { // Send heartbeat int sockfd = heartbeat_socket(); if (sockfd >= 0) sendhb(sockfd); close(sockfd); } void sighup(int i) { beat(); signal(SIGHUP, &sighup); } int main(int argc, char *argv[]) { int i; if (argc != 2) { fprintf(stderr, "heartbeat-client \n"); return -1; } if (!loadconfig(argv[1])) { fprintf(stderr, "Configuration incomplete\n"); return -1; } if (g_daemonize) { // Daemonize i = fork(); if (i < 0) { fprintf(stderr, "Couldn't fork\n"); return -1; } // Exit the mother fork if (i != 0) return 0; // Child fork setsid(); // Cleanup stdin/out/err freopen("/dev/null","r",stdin); freopen("/dev/null","w",stdout); freopen("/dev/null","w",stderr); hblog(LOG_INFO, "Running as pid %d\n", getpid()); } // Handle a SIGHUP to force a heartbeat signal(SIGHUP, &sighup); for (;;) { beat(); // Sleep sleep(g_sendinterval); } } heartbeat/common/0000775000175200017530000000000007740144010010052 5heartbeat/common/config.h0000664000175200017530000000140207740143743011421 /************************************** Defines **************************************/ #define PORT "3740" #define CONFIG "heartbeat.conf" #define HEARTBEAT_PID "/tmp/heartbeat.pid" #define CLOCK_OFF 120 // The maximum time in seconds that the // client clock is allowed to be off, thus use ntp synced clocks :) #define LISTEN_QUEUE 128 // For MD5 routines #define __USE_BSD 1 #include #define UWORD32 u_int32_t // Determine Endianness #if BYTE_ORDER == LITTLE_ENDIAN /* 1234 machines */ #elif BYTE_ORDER == BIG_ENDIAN /* 4321 machines */ # define WORDS_BIGENDIAN 1 #elif BYTE_ORDER == PDP_ENDIAN /* 3412 machines */ #error PDP endianness not supported yet! #else #error unknown endianness! #endif #include "md5.h" heartbeat/common/md5.c0000664000175200017530000001654207740143743010647 /* * This code implements the MD5 message-digest algorithm. * The algorithm is due to Ron Rivest. This code was * written by Colin Plumb in 1993, no copyright is claimed. * This code is in the public domain; do with it what you wish. * * Equivalent code is available from RSA Data Security, Inc. * This code has been tested against that, and is equivalent, * except that you don't need to include two pages of legalese * with every copy. * * To compute the message digest of a chunk of bytes, declare an * MD5Context structure, pass it to MD5Init, call MD5Update as * needed on buffers full of bytes, and then call MD5Final, which * will fill a supplied 16-byte array with the digest. * * Changed so as no longer to depend on Colin Plumb's `usual.h' header * definitions; now uses stuff from dpkg's config.h. * - Ian Jackson . * Still in the public domain. */ #include /* for memcpy() */ #include /* for stupid systems */ #include /* for ntohl() */ #include "config.h" #include "md5.h" #ifdef WORDS_BIGENDIAN void byteSwap(UWORD32 *buf, unsigned words) { md5byte *p = (md5byte *)buf; do { *buf++ = (UWORD32)((unsigned)p[3] << 8 | p[2]) << 16 | ((unsigned)p[1] << 8 | p[0]); p += 4; } while (--words); } #else #define byteSwap(buf,words) #endif /* * Start MD5 accumulation. Set bit count to 0 and buffer to mysterious * initialization constants. */ void MD5Init(struct MD5Context *ctx) { ctx->buf[0] = 0x67452301; ctx->buf[1] = 0xefcdab89; ctx->buf[2] = 0x98badcfe; ctx->buf[3] = 0x10325476; ctx->bytes[0] = 0; ctx->bytes[1] = 0; } /* * Update context to reflect the concatenation of another buffer full * of bytes. */ void MD5Update(struct MD5Context *ctx, md5byte const *buf, unsigned len) { UWORD32 t; /* Update byte count */ t = ctx->bytes[0]; if ((ctx->bytes[0] = t + len) < t) ctx->bytes[1]++; /* Carry from low to high */ t = 64 - (t & 0x3f); /* Space available in ctx->in (at least 1) */ if (t > len) { memcpy((md5byte *)ctx->in + 64 - t, buf, len); return; } /* First chunk is an odd size */ memcpy((md5byte *)ctx->in + 64 - t, buf, t); byteSwap(ctx->in, 16); MD5Transform(ctx->buf, ctx->in); buf += t; len -= t; /* Process data in 64-byte chunks */ while (len >= 64) { memcpy(ctx->in, buf, 64); byteSwap(ctx->in, 16); MD5Transform(ctx->buf, ctx->in); buf += 64; len -= 64; } /* Handle any remaining bytes of data. */ memcpy(ctx->in, buf, len); } /* * Final wrapup - pad to 64-byte boundary with the bit pattern * 1 0* (64-bit count of bits processed, MSB-first) */ void MD5Final(md5byte digest[16], struct MD5Context *ctx) { int count = ctx->bytes[0] & 0x3f; /* Number of bytes in ctx->in */ md5byte *p = (md5byte *)ctx->in + count; /* Set the first char of padding to 0x80. There is always room. */ *p++ = 0x80; /* Bytes of padding needed to make 56 bytes (-8..55) */ count = 56 - 1 - count; if (count < 0) { /* Padding forces an extra block */ memset(p, 0, count + 8); byteSwap(ctx->in, 16); MD5Transform(ctx->buf, ctx->in); p = (md5byte *)ctx->in; count = 56; } memset(p, 0, count); byteSwap(ctx->in, 14); /* Append length in bits and transform */ ctx->in[14] = ctx->bytes[0] << 3; ctx->in[15] = ctx->bytes[1] << 3 | ctx->bytes[0] >> 29; MD5Transform(ctx->buf, ctx->in); byteSwap(ctx->buf, 4); memcpy(digest, ctx->buf, 16); memset(ctx, 0, sizeof(ctx)); /* In case it's sensitive */ } #ifndef ASM_MD5 /* The four core functions - F1 is optimized somewhat */ /* #define F1(x, y, z) (x & y | ~x & z) */ #define F1(x, y, z) (z ^ (x & (y ^ z))) #define F2(x, y, z) F1(z, x, y) #define F3(x, y, z) (x ^ y ^ z) #define F4(x, y, z) (y ^ (x | ~z)) /* This is the central step in the MD5 algorithm. */ #define MD5STEP(f,w,x,y,z,in,s) \ (w += f(x,y,z) + in, w = (w<>(32-s)) + x) /* * The core of the MD5 algorithm, this alters an existing MD5 hash to * reflect the addition of 16 longwords of new data. MD5Update blocks * the data and converts bytes into longwords for this routine. */ void MD5Transform(UWORD32 buf[4], UWORD32 const in[16]) { register UWORD32 a, b, c, d; a = buf[0]; b = buf[1]; c = buf[2]; d = buf[3]; MD5STEP(F1, a, b, c, d, in[0] + 0xd76aa478, 7); MD5STEP(F1, d, a, b, c, in[1] + 0xe8c7b756, 12); MD5STEP(F1, c, d, a, b, in[2] + 0x242070db, 17); MD5STEP(F1, b, c, d, a, in[3] + 0xc1bdceee, 22); MD5STEP(F1, a, b, c, d, in[4] + 0xf57c0faf, 7); MD5STEP(F1, d, a, b, c, in[5] + 0x4787c62a, 12); MD5STEP(F1, c, d, a, b, in[6] + 0xa8304613, 17); MD5STEP(F1, b, c, d, a, in[7] + 0xfd469501, 22); MD5STEP(F1, a, b, c, d, in[8] + 0x698098d8, 7); MD5STEP(F1, d, a, b, c, in[9] + 0x8b44f7af, 12); MD5STEP(F1, c, d, a, b, in[10] + 0xffff5bb1, 17); MD5STEP(F1, b, c, d, a, in[11] + 0x895cd7be, 22); MD5STEP(F1, a, b, c, d, in[12] + 0x6b901122, 7); MD5STEP(F1, d, a, b, c, in[13] + 0xfd987193, 12); MD5STEP(F1, c, d, a, b, in[14] + 0xa679438e, 17); MD5STEP(F1, b, c, d, a, in[15] + 0x49b40821, 22); MD5STEP(F2, a, b, c, d, in[1] + 0xf61e2562, 5); MD5STEP(F2, d, a, b, c, in[6] + 0xc040b340, 9); MD5STEP(F2, c, d, a, b, in[11] + 0x265e5a51, 14); MD5STEP(F2, b, c, d, a, in[0] + 0xe9b6c7aa, 20); MD5STEP(F2, a, b, c, d, in[5] + 0xd62f105d, 5); MD5STEP(F2, d, a, b, c, in[10] + 0x02441453, 9); MD5STEP(F2, c, d, a, b, in[15] + 0xd8a1e681, 14); MD5STEP(F2, b, c, d, a, in[4] + 0xe7d3fbc8, 20); MD5STEP(F2, a, b, c, d, in[9] + 0x21e1cde6, 5); MD5STEP(F2, d, a, b, c, in[14] + 0xc33707d6, 9); MD5STEP(F2, c, d, a, b, in[3] + 0xf4d50d87, 14); MD5STEP(F2, b, c, d, a, in[8] + 0x455a14ed, 20); MD5STEP(F2, a, b, c, d, in[13] + 0xa9e3e905, 5); MD5STEP(F2, d, a, b, c, in[2] + 0xfcefa3f8, 9); MD5STEP(F2, c, d, a, b, in[7] + 0x676f02d9, 14); MD5STEP(F2, b, c, d, a, in[12] + 0x8d2a4c8a, 20); MD5STEP(F3, a, b, c, d, in[5] + 0xfffa3942, 4); MD5STEP(F3, d, a, b, c, in[8] + 0x8771f681, 11); MD5STEP(F3, c, d, a, b, in[11] + 0x6d9d6122, 16); MD5STEP(F3, b, c, d, a, in[14] + 0xfde5380c, 23); MD5STEP(F3, a, b, c, d, in[1] + 0xa4beea44, 4); MD5STEP(F3, d, a, b, c, in[4] + 0x4bdecfa9, 11); MD5STEP(F3, c, d, a, b, in[7] + 0xf6bb4b60, 16); MD5STEP(F3, b, c, d, a, in[10] + 0xbebfbc70, 23); MD5STEP(F3, a, b, c, d, in[13] + 0x289b7ec6, 4); MD5STEP(F3, d, a, b, c, in[0] + 0xeaa127fa, 11); MD5STEP(F3, c, d, a, b, in[3] + 0xd4ef3085, 16); MD5STEP(F3, b, c, d, a, in[6] + 0x04881d05, 23); MD5STEP(F3, a, b, c, d, in[9] + 0xd9d4d039, 4); MD5STEP(F3, d, a, b, c, in[12] + 0xe6db99e5, 11); MD5STEP(F3, c, d, a, b, in[15] + 0x1fa27cf8, 16); MD5STEP(F3, b, c, d, a, in[2] + 0xc4ac5665, 23); MD5STEP(F4, a, b, c, d, in[0] + 0xf4292244, 6); MD5STEP(F4, d, a, b, c, in[7] + 0x432aff97, 10); MD5STEP(F4, c, d, a, b, in[14] + 0xab9423a7, 15); MD5STEP(F4, b, c, d, a, in[5] + 0xfc93a039, 21); MD5STEP(F4, a, b, c, d, in[12] + 0x655b59c3, 6); MD5STEP(F4, d, a, b, c, in[3] + 0x8f0ccc92, 10); MD5STEP(F4, c, d, a, b, in[10] + 0xffeff47d, 15); MD5STEP(F4, b, c, d, a, in[1] + 0x85845dd1, 21); MD5STEP(F4, a, b, c, d, in[8] + 0x6fa87e4f, 6); MD5STEP(F4, d, a, b, c, in[15] + 0xfe2ce6e0, 10); MD5STEP(F4, c, d, a, b, in[6] + 0xa3014314, 15); MD5STEP(F4, b, c, d, a, in[13] + 0x4e0811a1, 21); MD5STEP(F4, a, b, c, d, in[4] + 0xf7537e82, 6); MD5STEP(F4, d, a, b, c, in[11] + 0xbd3af235, 10); MD5STEP(F4, c, d, a, b, in[2] + 0x2ad7d2bb, 15); MD5STEP(F4, b, c, d, a, in[9] + 0xeb86d391, 21); buf[0] += a; buf[1] += b; buf[2] += c; buf[3] += d; } #endif heartbeat/common/md5.h0000664000175200017530000000245107740143743010646 /* * This is the header file for the MD5 message-digest algorithm. * The algorithm is due to Ron Rivest. This code was * written by Colin Plumb in 1993, no copyright is claimed. * This code is in the public domain; do with it what you wish. * * Equivalent code is available from RSA Data Security, Inc. * This code has been tested against that, and is equivalent, * except that you don't need to include two pages of legalese * with every copy. * * To compute the message digest of a chunk of bytes, declare an * MD5Context structure, pass it to MD5Init, call MD5Update as * needed on buffers full of bytes, and then call MD5Final, which * will fill a supplied 16-byte array with the digest. * * Changed so as no longer to depend on Colin Plumb's `usual.h' * header definitions; now uses stuff from dpkg's config.h * - Ian Jackson . * Still in the public domain. */ #ifndef MD5_H #define MD5_H #define md5byte unsigned char struct MD5Context { UWORD32 buf[4]; UWORD32 bytes[2]; UWORD32 in[16]; }; void MD5Init(struct MD5Context *context); void MD5Update(struct MD5Context *context, md5byte const *buf, unsigned len); void MD5Final(unsigned char digest[16], struct MD5Context *context); void MD5Transform(UWORD32 buf[4], UWORD32 const in[16]); #endif /* !MD5_H */ heartbeat/common/linklist.c0000664000175200017530000001124207740143743012003 /* Generic linked list routine. * Copyright (C) 1997, 2000 Kunihiro Ishiguro */ #include "linklist.h" #include #include #include /* Allocate new list. */ struct list * list_new () { struct list *new; new = malloc (sizeof (struct list)); memset (new, 0, sizeof (struct list)); return new; } /* Free list. */ void list_free (struct list *l) { free (l); } /* Allocate new listnode. Internal use only. */ static struct listnode * listnode_new () { struct listnode *node; node = malloc (sizeof (struct listnode)); memset (node, 0, sizeof (struct listnode)); return node; } /* Free listnode. */ static void listnode_free (struct listnode *node) { free (node); } /* Add new data to the list. */ void listnode_add (struct list *list, void *val) { struct listnode *node; node = listnode_new (); node->prev = list->tail; node->data = val; if (list->head == NULL) list->head = node; else list->tail->next = node; list->tail = node; list->count++; } /* Add new node with sort function. */ void listnode_add_sort (struct list *list, void *val) { struct listnode *n; struct listnode *new; new = listnode_new (); new->data = val; if (list->cmp) { for (n = list->head; n; n = n->next) { if ((*list->cmp) (val, n->data) < 0) { new->next = n; new->prev = n->prev; if (n->prev) n->prev->next = new; else list->head = new; n->prev = new; list->count++; return; } } } new->prev = list->tail; if (list->tail) list->tail->next = new; else list->head = new; list->tail = new; list->count++; } void listnode_add_after (struct list *list, struct listnode *pp, void *val) { struct listnode *nn; nn = listnode_new (); nn->data = val; if (pp == NULL) { if (list->head) list->head->prev = nn; else list->tail = nn; nn->next = list->head; nn->prev = pp; list->head = nn; } else { if (pp->next) pp->next->prev = nn; else list->tail = nn; nn->next = pp->next; nn->prev = pp; pp->next = nn; } } /* Delete specific date pointer from the list. */ void listnode_delete (struct list *list, void *val) { struct listnode *node; for (node = list->head; node; node = node->next) { if (node->data == val) { if (node->prev) node->prev->next = node->next; else list->head = node->next; if (node->next) node->next->prev = node->prev; else list->tail = node->prev; list->count--; listnode_free (node); return; } } } /* Delete all listnode from the list. */ void list_delete_all_node (struct list *list) { struct listnode *node; struct listnode *next; for (node = list->head; node; node = next) { next = node->next; if (list->del) (*list->del) (node->data); listnode_free (node); } list->head = list->tail = NULL; list->count = 0; } /* Delete all listnode then free list itself. */ void list_delete (struct list *list) { struct listnode *node; struct listnode *next; for (node = list->head; node; node = next) { next = node->next; if (list->del) (*list->del) (node->data); listnode_free (node); } list_free (list); } /* Lookup the node which has given data. */ struct listnode * listnode_lookup (struct list *list, void *data) { struct listnode *node; for (node = list->head; node; nextnode (node)) if (data == getdata (node)) return node; return NULL; } /* Delete the node from list. For ospfd and ospf6d. */ void list_delete_node (struct list *list, struct listnode *node) { if (node->prev) node->prev->next = node->next; else list->head = node->next; if (node->next) node->next->prev = node->prev; else list->tail = node->prev; list->count--; listnode_free (node); } void list_add_node_prev (struct list *list, struct listnode *current, void *val) { struct listnode *node; node = listnode_new (); node->next = current; node->data = val; if (current->prev == NULL) list->head = node; else current->prev->next = node; node->prev = current->prev; current->prev = node; list->count++; } void list_add_node_next (struct list *list, struct listnode *current, void *val) { struct listnode *node; node = listnode_new (); node->prev = current; node->data = val; if (current->next == NULL) list->tail = node; else current->next->prev = node; node->next = current->next; current->next = node; list->count++; } void list_add_list (struct list *l, struct list *m) { struct listnode *n; for (n = listhead (m); n; nextnode (n)) listnode_add (l, n->data); } heartbeat/common/linklist.h0000664000175200017530000000370207740143743012012 /* Generic linked list * Copyright (C) 1997, 2000 Kunihiro Ishiguro */ #ifndef __LINKLIST_H #define __LINKLIST_H struct list; struct listnode; struct listnode { struct listnode *next; struct listnode *prev; void *data; }; struct list { struct listnode *head; struct listnode *tail; unsigned int count; int (*cmp) (void *val1, void *val2); void (*del) (void *val); }; #define nextnode(X) ((X) = (X)->next) #define listhead(X) ((X)->head) #define listcount(X) ((X)->count) #define list_isempty(X) ((X)->head == NULL && (X)->tail == NULL) #define getdata(X) ((X)->data) /* Prototypes. */ struct list *list_new(); void list_free (struct list *); void listnode_add (struct list *, void *); void listnode_add_sort (struct list *, void *); void listnode_add_after (struct list *, struct listnode *, void *); void listnode_delete (struct list *, void *); struct listnode *listnode_lookup (struct list *, void *); void list_delete (struct list *); void list_delete_all_node (struct list *); /* For ospfd and ospf6d. */ void list_delete_node (struct list *, struct listnode *); /* For ospf_spf.c */ void list_add_node_prev (struct list *, struct listnode *, void *); void list_add_node_next (struct list *, struct listnode *, void *); void list_add_list (struct list *, struct list *); /* List iteration macro. */ #define LIST_LOOP(L,V,N) \ for ((N) = (L)->head; (N); (N) = (N)->next) \ if (((V) = (N)->data) != NULL) /* List node add macro. */ #define LISTNODE_ADD(L,N) \ do { \ (N)->prev = (L)->tail; \ if ((L)->head == NULL) \ (L)->head = (N); \ else \ (L)->tail->next = (N); \ (L)->tail = (N); \ } while (0) /* List node delete macro. */ #define LISTNODE_DELETE(L,N) \ do { \ if ((N)->prev) \ (N)->prev->next = (N)->next; \ else \ (L)->head = (N)->next; \ if ((N)->next) \ (N)->next->prev = (N)->prev; \ else \ (L)->tail = (N)->prev; \ } while (0) #endif /* __LINKLIST_H */ heartbeat/doc/0000775000175200017530000000000007740143766007350 5heartbeat/doc/README0000664000175200017530000000312507740143743010144 SixXS Heartbeat Client/Server ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ The heartbeat protocol as described in the draft uses the IANA assigned port 3740 (*1) for communication to notify a POP of IPv4 endpoint changes and the reachability of the client. In short it sends a heartbeat every 60 seconds containing: HEARTBEAT TUNNEL 2001:db8::2 10.100.13.42 1063665852 hartslag This is md5'd, password removed, md5 added and thus the following string is transmitted to the POP's IPv4 per UDP: HEARTBEAT TUNNEL 2001:db8::2 10.100.13.42 1063665852 da46fdc28f568bb62d29661f73758095 If there is no heartbeat for 300 seconds the POP automatically disables the tunnel. If the IPv4 address changes, the tunnel is again automatically reconfigured to the new address. If the tunnel was down it is configured to be up on the heartbeat. All of this makes sure that traffic won't be transmitted to unsuspecting endpoints in case an endpoint is on a dialup connection or other fast-changing endpoint. Note: Keep your machine NTP synced, if the timestamp difference is bigger than 120 seconds the heartbeat will be silently dropped. Comments and questions should be directed to info@sixxs.net or the SixXS Forums for discussions. Server/POP side of the code is closed for the time being. Jeroen Massar / SixXS Staff jeroen@sixxs.net The software can be downloaded from: http://www.sixxs.net/archive/heartbeat/ *1 = IANA port 3740 http://www.iana.org/assignments/port-numbers heartbeat 3740/tcp Heartbeat Protocol heartbeat 3740/udp Heartbeat Protocol # Jeroen Massar April 2003 heartbeat/doc/draft-massar-v6ops-heartbeat-00.txt0000664000175200017530000003070007740143743015635 Internet Engineering Task Force Jeroen Massar Internet Draft Unfix/SixXS Expiration Date: Mar 2004 September 2003 Heartbeat Protocol draft-massar-v6ops-heartbeat-00.txt Status of this Memo This document is an Internet-Draft and is subject to all provisions of Section 10 of RFC2026. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet- Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt. To view the list Internet-Draft Shadow Directories, see http://www.ietf.org/shadow.html. Abstract This document proposes a heartbeat protocol for controlling tunnel availability and allowing dynamic non-24/7 endnodes to use tunnels. Massar, Jeroen [Expires Mar 2004] [Page 1] Internet Draft draft-massar-v6ops-heartbeat-00.txt September 2003 Table of Contents 1. Introduction ............................................... 2 2. Heartbeat protocol .......................................... 3 2.1. Heartbeat command ........................................ 4 2.2. Disable command .......................................... 4 3. Acknowledgements ............................................ 5 4. Security Considerations ..................................... 5 5. References .................................................. 6 Author's Address ................................................ 6 1. Introduction When operating a Tunnel Broker [RFC3053] or any other form of tunneling across the internet one doesn't want to send packets out to unsuspecting endpoints. Unsuspecting endpoints are hosts which don't expect traffic from the TB This is a common scenario when a non-static endpoint is used. The user enables the tunnel to the current endpoint, uses it and then disconnects from the internet or gets assigned another IP, due to dhcp policies or related reasons. The endpoint of the tunnel changes but there currently is no way of automatically changing that endpoint or notifying the POP that it has changed. Then another host get to use the IP and suddenly it receives our tunneled packets. Many hosts emply so called firewall or logging facilities that will start complaining about packets being sent from the Tunnel Broker which they perceive as malicious. The user of this firewall will in turn start complaining about abuse and hack attempts which takes up time from the persons running the Tunnel Broker staff and not even mentioning all the entites that will be notified by these type of messages. This protocol resolves this problem by specifying a heartbeat protocol. As long as the tunnel endpoint is able to send an authenticated heartbeat packet the tunnel is kept configured allowing two-way traffic to be sent. This heartbeat protocol also allows for automatic tunnel reconfiguration so that in the event of an IP change at the client side the tunnel will be reconfigured allowing continued service without notable interruption. If the Tunnel Broker's POP doesn't receive a heartbeat for a certain amount of time it can deem the endpoint as down and turn the tunnel down too. Taking these two into consideration will stop the sending of tunneled packets and will thus avoid the complaints which could have been brought up before. The implementation of this protocol will allow SixXS [SIXXS] users to request tunnels to dynamic endpoints that don't have to be reachable 24/7. This was before this protocol was implement one of the few requirements of obtaining a tunnel even when the project only consisted of one POP and was called IPng [IPNG]. This protocol covers all tunneling protocols which use at least one set of inner and one set of outer addresses. Note that some of these protocols already have a heartbeat mechanism in the protocol. In those cases it is of course advisable to use that mechanism. Massar, Jeroen [Expires Mar 2004] [Page 2] Internet Draft draft-massar-v6ops-heartbeat-00.txt September 2003 2. Heartbeat Protocol The heartbeat packet is a UDP [UDP] packet to port {IANA} of the tunnel's underlying endpoint. Schematically this will look like the following diagram for a IPv6 in IPv4 (proto-41) tunnel [6IN4], which currently is widely used on the 6bone [6BONE]. Note that this protocol is not limited to 6in4 but can also be used together with for example GRE [GRE], IPXIP [IPXIP] and PPTP [PPTP]. This setup is also used for the other examples in this document. +--------+ +--------+ | Client | <--- IPv6 in IPv4 Tunnel ---> | Server | +--------+ +--------+ Server's Outer IPv4: 172.16.1.2 Server's Inner IPv6: 2001:db8::1/64 Client's Outer IPv4: 10.100.13.42 Client's Inner IPv6: 2001:db8::2/64 A tunnel has both 'outer' IP's, the public addresses over which the tunneled packets are sent and 'inner' IP's, the addresses assigned to the tunnel endpoints. The Server will be referred to as POP (Point of presence) in the rest of this document. The heartbeat packet consists out of one single string separated by spaces and ending in a NULL. The first string is a 'command', allowing extension of this protocol if needed. The basic heartbeat packet looks like: ::= ::= | ::= ::= | ::= ::= the NULL character (ASCII code 0) The packet must be constructed first with the signature containing the password for the tunnel. After construction the md5-signature should be calculated and then replace the cleartext-password. The packet can then be sent onto the network. Massar, Jeroen [Expires Mar 2004] [Page 3] Internet Draft draft-massar-v6ops-heartbeat-00.txt September 2003 The currently defined commands HEARTBEAT and DISABLE both use the following common options to identify the tunnel for which this heartbeat is meant: ::= (HOST | TUNNEL ) ::= ::= ::= ::= ::= | | <...> 2.1. Heartbeat Command This command is the main reason for this protocol to exist. It tells the POP that the current endpoint specified by both the UDP's source address and the common-option's outer endpoint is still accepting tunneled packets. Specification: ::= HEARTBEAT Example's: C: HEARTBEAT HOST 10.100.13.42 1525322 C: HEARTBEAT TUNNEL 2001:db8::2 10.100.13.42 121313 2.2. Disable Command The disable command explicitly sets a tunnel 'down' on the POP allowing a gracious and prompt shutdown of the tunnel on the POP. One could even employ this command to stop huge traffic flows to the local endpoint which maybe could not cope with the traffic passed over it through the tunnel. Specification: ::= DISABLE Example: C: DISABLE 10.100.13.42 2001:db8::2/64 2003-02-17 01:04 Massar, Jeroen [Expires Mar 2004] [Page 4] Internet Draft draft-massar-v6ops-heartbeat-00.txt September 2003 3. Acknowledgements The protocol presented has formed during the existence of IPng [IPNG] and SixXS [SIXXS] to allow the users of these tunnel broker systems to have a dynamic non-static IPv4 endpoint. Thus I would like to thank the numberous users requesting the support for dynamic non-static tunnels. 4. Security Considerations The password used for creating the MD5 signature should never be made publicly available to 3rd parties otherwise that 3rd party could sign a packet and automatically reconfigure the tunnel endpoint. This could lead into the 3rd party sending traffic in both directions and thus posing as the actual user. The inclusion of the timestamp along with the verification on the POP side should guard against any replay attack. The POP must limit that the local clock compared to the timestamp from the packet should never differ for more than 2 minutes, this allows for at some latency and time-desync. Any packet that is not well formed or contains a invalid signature should be silently dropped. A side effect of this protocol is that whenever the local host cannot send a heartbeat in time to the POP that the POP will shutdown the tunnel. Envision a Denial of Service over the tunnel to the local endpoint. The local host's heartbeat cannot reach the POP which in turn will automatically disable the tunnel, allowing the host to catch some breath again and thus effectively implementing a poor mans rate limiting. Massar, Jeroen [Expires Mar 2004] [Page 5] Internet Draft draft-massar-v6ops-heartbeat-00.txt September 2003 5. Scenarios 5.1 Host heartbeat 5.2 IPv6 in IPv4 tunnel heartbeat This scenario handles the case where a IPv6 in IPv4 tunnel [6IN4] is setup between two hosts. This is the normal case for a Tunnel Broker system with which a IPv4 only host is given acces to a IPv6 network. A tunnel like this can easily be setup using the Tunnel Setup Protocol [TSP] or similar protocols. A diagram of such a setup: +--------+ +--------+ | Client | <--- IPv6 in IPv4 Tunnel ---> | Server | +--------+ +--------+ Server's Outer IPv4: 172.16.1.2 Server's Inner IPv6: 2001:db8::1/64 Client's Outer IPv4: 10.100.13.42 Client's Inner IPv6: 2001:db8::2/64 Password : hartslag The command would be: HEARTBEAT TUNNEL 2001:db8::2 10.100.13.42 1063665852 hartslag The data to be transmitted is: HEARTBEAT TUNNEL 2001:db8::2 10.100.13.42 1063665852 da46fdc28f568bb62d29661f73758095 Note ofcourse that RFC1918 addresses will never reach a POP. Massar, Jeroen [Expires Mar 2004] [Page 6] Internet Draft draft-massar-v6ops-heartbeat-00.txt September 2003 6. References [6BONE] 6Bone, "testbed for deployment of IPv6", http://www.6bone.net/ [6IN4] R. Gilligan, E. Nordmark, "Transition Mechanisms for IPv6 Hosts and Routers", August 2000, RFC2893 [GRE] D. Farinacci, T. Li, S. Hanks, D. Meyer, P. Traina, "Generic Routing Encapsulation", March 2000, RFC2784 [IPNG] Pim van Pelt and Jeroen Massar, IPng, "IPv6 Enduser Deployment", http://www.ipng.nl [IPXIP] Provan, D., "Tunneling IPX Traffic through IP Networks", June 1991, RFC 1234 [PPTP] Hamzeh, K., et al., "Point-to-Point Tunneling Protocol (PPTP)", July 1999, RFC 2637 [SIXXS] Jeroen Massar and Pim van Pelt, SixXS "IPv6 Deployment", http://www.sixxs.net [TCP] DARPA, "Transmission Control Protocol (TCP)", September 1981, RFC 793 [TSP] Blanchet, M., "Tunnel Setup Protocol", July 2001, draft-vg-ngtrans-tsp-01.txt [UDP] Postel, J., "User Datagram Protocol", August 1980, RFC 768 Author's Address Jeroen Massar Unfix/SixXS Hofpoldersingel 45 2807 LW Gouda The Netherlands EMail: jeroen@unfix.org Massar, Jeroen [Expires Mar 2004] [Page 7] heartbeat/doc/TODO0000664000175200017530000000022607740143743007753 - Full Windows support (seperate Windows client is upcoming) - Testing on various platforms - More platforms - SixXS Configuration service support heartbeat/doc/changelog0000664000175200017530000000303707740143743011140 heartbeat (2003-09-06) stable * Added NetBSD support. * Automatic endian configuration. * Swapped g_ipv4_interface with the correct g_ipv6_interface. * Added note about NTP syncing of the client's clock. * Standard configuration now uses pop's hostname and tunnel endpoints out of 2001:db8::/32. * Heartbeat frequency set to standard 60 seconds. -- Jeroen Massar Mon, 6 Sep 2003 03:33:42 +0100 heartbeat (2003-09-25) stable * local resolve support thus one can heartbeat using another IP, getting the IP from DNS Handy for NAT constructions where you can put the external IP in DNS. No, this doesn't allow random IP's to be put in the packet, the IP contained in the packet *must* match the IP from which the packet came. * 'statictunnel' Don't change local tunnel endpoint, also allows one to run the client as non-root as bindtodevice is not done * daemonize Set it to 0 to not detach the client, handy for debugging. * sigHUP will now cause an immediate heartbeat to be sent. eg for use in "killall -HUP heartbeat-client" in dhclient's script. Wrapped logging into hblog() function and seperated beating into beat(). -- Jeroen Massar Thu, 25 Sep 2003 17:56:42 +0100 heartbeat (2003-09-18) stable * Update fixing the changing of the local tunnel endpoint. -- Jeroen Massar Thu, 18 Sep 2003 12:23:42 +0100 heartbeat (2003-09-15) stable * Initial public release -- Jeroen Massar Mon, 15 Sep 2003 23:10:24 +0100 heartbeat/doc/LICENSE0000664000175200017530000004435707740143743010305 "This software program is licensed subject to the GNU General Public License (GPL). Version 2, June 1991, available at " GNU General Public License Version 2, June 1991 Copyright (C) 1989, 1991 Free Software Foundation, Inc. 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA Everyone is permitted to copy and distribute verbatim copies of this license document, but changing it is not allowed. Preamble The licenses for most software are designed to take away your freedom to share and change it. By contrast, the GNU General Public License is intended to guarantee your freedom to share and change free software--to make sure the software is free for all its users. This General Public License applies to most of the Free Software Foundation's software and to any other program whose authors commit to using it. (Some other Free Software Foundation software is covered by the GNU Library General Public License instead.) You can apply it to your programs, too. When we speak of free software, we are referring to freedom, not price. Our General Public Licenses are designed to make sure that you have the freedom to distribute copies of free software (and charge for this service if you wish), that you receive source code or can get it if you want it, that you can change the software or use pieces of it in new free programs; and that you know you can do these things. To protect your rights, we need to make restrictions that forbid anyone to deny you these rights or to ask you to surrender the rights. These restrictions translate to certain responsibilities for you if you distribute copies of the software, or if you modify it. For example, if you distribute copies of such a program, whether gratis or for a fee, you must give the recipients all the rights that you have. You must make sure that they, too, receive or can get the source code. And you must show them these terms so they know their rights. We protect your rights with two steps: (1) copyright the software, and (2) offer you this license which gives you legal permission to copy, distribute and/or modify the software. Also, for each author's protection and ours, we want to make certain that everyone understands that there is no warranty for this free software. If the software is modified by someone else and passed on, we want its recipients to know that what they have is not the original, so that any problems introduced by others will not reflect on the original authors' reputations. Finally, any free program is threatened constantly by software patents. We wish to avoid the danger that redistributors of a free program will individually obtain patent licenses, in effect making the program proprietary. To prevent this, we have made it clear that any patent must be licensed for everyone's free use or not licensed at all. The precise terms and conditions for copying, distribution and modification follow. TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION 0. This License applies to any program or other work which contains a notice placed by the copyright holder saying it may be distributed under the terms of this General Public License. The "Program", below, refers to any such program or work, and a "work based on the Program" means either the Program or any derivative work under copyright law: that is to say, a work containing the Program or a portion of it, either verbatim or with modifications and/or translated into another language. (Hereinafter, translation is included without limitation in the term "modification".) Each licensee is addressed as "you". Activities other than copying, distribution and modification are not covered by this License; they are outside its scope. The act of running the Program is not restricted, and the output from the Program is covered only if its contents constitute a work based on the Program (independent of having been made by running the Program). Whether that is true depends on what the Program does. 1. You may copy and distribute verbatim copies of the Program's source code as you receive it, in any medium, provided that you conspicuously and appropriately publish on each copy an appropriate copyright notice and disclaimer of warranty; keep intact all the notices that refer to this License and to the absence of any warranty; and give any other recipients of the Program a copy of this License along with the Program. You may charge a fee for the physical act of transferring a copy, and you may at your option offer warranty protection in exchange for a fee. 2. You may modify your copy or copies of the Program or any portion of it, thus forming a work based on the Program, and copy and distribute such modifications or work under the terms of Section 1 above, provided that you also meet all of these conditions: * a) You must cause the modified files to carry prominent notices stating that you changed the files and the date of any change. * b) You must cause any work that you distribute or publish, that in whole or in part contains or is derived from the Program or any part thereof, to be licensed as a whole at no charge to all third parties under the terms of this License. * c) If the modified program normally reads commands interactively when run, you must cause it, when started running for such interactive use in the most ordinary way, to print or display an announcement including an appropriate copyright notice and a notice that there is no warranty (or else, saying that you provide a warranty) and that users may redistribute the program under these conditions, and telling the user how to view a copy of this License. (Exception: if the Program itself is interactive but does not normally print such an announcement, your work based on the Program is not required to print an announcement.) These requirements apply to the modified work as a whole. If identifiable sections of that work are not derived from the Program, and can be reasonably considered independent and separate works in themselves, then this License, and its terms, do not apply to those sections when you distribute them as separate works. But when you distribute the same sections as part of a whole which is a work based on the Program, the distribution of the whole must be on the terms of this License, whose permissions for other licensees extend to the entire whole, and thus to each and every part regardless of who wrote it. Thus, it is not the intent of this section to claim rights or contest your rights to work written entirely by you; rather, the intent is to exercise the right to control the distribution of derivative or collective works based on the Program. In addition, mere aggregation of another work not based on the Program with the Program (or with a work based on the Program) on a volume of a storage or distribution medium does not bring the other work under the scope of this License. 3. You may copy and distribute the Program (or a work based on it, under Section 2) in object code or executable form under the terms of Sections 1 and 2 above provided that you also do one of the following: * a) Accompany it with the complete corresponding machine-readable source code, which must be distributed under the terms of Sections 1 and 2 above on a medium customarily used for software interchange; or, * b) Accompany it with a written offer, valid for at least three years, to give any third party, for a charge no more than your cost of physically performing source distribution, a complete machine- readable copy of the corresponding source code, to be distributed under the terms of Sections 1 and 2 above on a medium customarily used for software interchange; or, * c) Accompany it with the information you received as to the offer to distribute corresponding source code. (This alternative is allowed only for noncommercial distribution and only if you received the program in object code or executable form with such an offer, in accord with Subsection b above.) The source code for a work means the preferred form of the work for making modifications to it. For an executable work, complete source code means all the source code for all modules it contains, plus any associated interface definition files, plus the scripts used to control compilation and installation of the executable. However, as a special exception, the source code distributed need not include anything that is normally distributed (in either source or binary form) with the major components (compiler, kernel, and so on) of the operating system on which the executable runs, unless that component itself accompanies the executable. If distribution of executable or object code is made by offering access to copy from a designated place, then offering equivalent access to copy the source code from the same place counts as distribution of the source code, even though third parties are not compelled to copy the source along with the object code. 4. You may not copy, modify, sublicense, or distribute the Program except as expressly provided under this License. Any attempt otherwise to copy, modify, sublicense or distribute the Program is void, and will automatically terminate your rights under this License. However, parties who have received copies, or rights, from you under this License will not have their licenses terminated so long as such parties remain in full compliance. 5. You are not required to accept this License, since you have not signed it. However, nothing else grants you permission to modify or distribute the Program or its derivative works. These actions are prohibited by law if you do not accept this License. Therefore, by modifying or distributing the Program (or any work based on the Program), you indicate your acceptance of this License to do so, and all its terms and conditions for copying, distributing or modifying the Program or works based on it. 6. Each time you redistribute the Program (or any work based on the Program), the recipient automatically receives a license from the original licensor to copy, distribute or modify the Program subject to these terms and conditions. You may not impose any further restrictions on the recipients' exercise of the rights granted herein. You are not responsible for enforcing compliance by third parties to this License. 7. If, as a consequence of a court judgment or allegation of patent infringement or for any other reason (not limited to patent issues), conditions are imposed on you (whether by court order, agreement or otherwise) that contradict the conditions of this License, they do not excuse you from the conditions of this License. If you cannot distribute so as to satisfy simultaneously your obligations under this License and any other pertinent obligations, then as a consequence you may not distribute the Program at all. For example, if a patent license would not permit royalty-free redistribution of the Program by all those who receive copies directly or indirectly through you, then the only way you could satisfy both it and this License would be to refrain entirely from distribution of the Program. If any portion of this section is held invalid or unenforceable under any particular circumstance, the balance of the section is intended to apply and the section as a whole is intended to apply in other circumstances. It is not the purpose of this section to induce you to infringe any patents or other property right claims or to contest validity of any such claims; this section has the sole purpose of protecting the integrity of the free software distribution system, which is implemented by public license practices. Many people have made generous contributions to the wide range of software distributed through that system in reliance on consistent application of that system; it is up to the author/donor to decide if he or she is willing to distribute software through any other system and a licensee cannot impose that choice. This section is intended to make thoroughly clear what is believed to be a consequence of the rest of this License. 8. If the distribution and/or use of the Program is restricted in certain countries either by patents or by copyrighted interfaces, the original copyright holder who places the Program under this License may add an explicit geographical distribution limitation excluding those countries, so that distribution is permitted only in or among countries not thus excluded. In such case, this License incorporates the limitation as if written in the body of this License. 9. The Free Software Foundation may publish revised and/or new versions of the General Public License from time to time. Such new versions will be similar in spirit to the present version, but may differ in detail to address new problems or concerns. Each version is given a distinguishing version number. If the Program specifies a version number of this License which applies to it and "any later version", you have the option of following the terms and conditions either of that version or of any later version published by the Free Software Foundation. If the Program does not specify a version number of this License, you may choose any version ever published by the Free Software Foundation. 10. If you wish to incorporate parts of the Program into other free programs whose distribution conditions are different, write to the author to ask for permission. For software which is copyrighted by the Free Software Foundation, write to the Free Software Foundation; we sometimes make exceptions for this. Our decision will be guided by the two goals of preserving the free status of all derivatives of our free software and of promoting the sharing and reuse of software generally. NO WARRANTY 11. BECAUSE THE PROGRAM IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY APPLICABLE LAW. EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE PROGRAM IS WITH YOU. SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING, REPAIR OR CORRECTION. 12. IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY AND/OR REDISTRIBUTE THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. END OF TERMS AND CONDITIONS How to Apply These Terms to Your New Programs If you develop a new program, and you want it to be of the greatest possible use to the public, the best way to achieve this is to make it free software which everyone can redistribute and change under these terms. To do so, attach the following notices to the program. It is safest to attach them to the start of each source file to most effectively convey the exclusion of warranty; and each file should have at least the "copyright" line and a pointer to where the full notice is found. one line to give the program's name and an idea of what it does. Copyright (C) yyyy name of author This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. Also add information on how to contact you by electronic and paper mail. If the program is interactive, make it output a short notice like this when it starts in an interactive mode: Gnomovision version 69, Copyright (C) year name of author Gnomovision comes with ABSOLUTELY NO WARRANTY; for details type 'show w'. This is free software, and you are welcome to redistribute it under certain conditions; type 'show c' for details. The hypothetical commands 'show w' and 'show c' should show the appropriate parts of the General Public License. Of course, the commands you use may be called something other than 'show w' and 'show c'; they could even be mouse-clicks or menu items--whatever suits your program. You should also get your employer (if you work as a programmer) or your school, if any, to sign a "copyright disclaimer" for the program, if necessary. Here is a sample; alter the names: Yoyodyne, Inc., hereby disclaims all copyright interest in the program 'Gnomovision' (which makes passes at compilers) written by James Hacker. signature of Ty Coon, 1 April 1989 Ty Coon, President of Vice This General Public License does not permit incorporating your program into proprietary programs. If your program is a subroutine library, you may consider it more useful to permit linking proprietary applications with the library. If this is what you want to do, use the GNU Library General Public License instead of this License.