text: /*
   * multilink.c - support routines for multilink.
   *
   * Copyright (c) 2000-2002 Paul Mackerras. All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   *
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   *
   * 2. The name(s) of the authors of this software must not be used to
   *    endorse or promote products derived from this software without
   *    prior written permission.
   *
   * 3. Redistributions of any form whatsoever must retain the following
   *    acknowledgment:
   *    "This product includes software developed by Paul Mackerras
   *     <paulus@samba.org>".
   *
   * THE AUTHORS OF THIS SOFTWARE DISCLAIM ALL WARRANTIES WITH REGARD TO
   * THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
   * AND FITNESS, IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY
   * SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
   * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN
   * AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
   * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
   */
  
  #include "lwip/opt.h"
  #if PPP_SUPPORT && defined(HAVE_MULTILINK) /* don't build if not configured for use in lwipopts.h */
  
  /* Multilink support
   *
   * Multilink uses Samba TDB (Trivial Database Library), which
   * we cannot port, because it needs a filesystem.
   *
   * We have to choose between doing a memory-shared TDB-clone,
   * or dropping multilink support at all.
   */
  
  #include <string.h>
  #include <ctype.h>
  #include <stdlib.h>
  #include <netdb.h>
  #include <errno.h>
  #include <signal.h>
  #include <netinet/in.h>
  #include <unistd.h>
  
  #include "netif/ppp/ppp_impl.h"
  
  #include "netif/ppp/fsm.h"
  #include "netif/ppp/lcp.h"
  #include "netif/ppp/tdb.h"
  
  bool endpoint_specified;	/* user gave explicit endpoint discriminator */
  char *bundle_id;		/* identifier for our bundle */
  char *blinks_id;		/* key for the list of links */
  bool doing_multilink;		/* multilink was enabled and agreed to */
  bool multilink_master;		/* we own the multilink bundle */
  
  extern TDB_CONTEXT *pppdb;
  extern char db_key[];
  
  static void make_bundle_links (int append);
  static void remove_bundle_link (void);
  static void iterate_bundle_links (void (*func) (char *));
  
  static int get_default_epdisc (struct epdisc *);
  static int parse_num (char *str, const char *key, int *valp);
  static int owns_unit (TDB_DATA pid, int unit);
  
  #define set_ip_epdisc(ep, addr) do {	\
  	ep->length = 4;			\
  	ep->value[0] = addr >> 24;	\
  	ep->value[1] = addr >> 16;	\
  	ep->value[2] = addr >> 8;	\
  	ep->value[3] = addr;		\
  } while (0)
  
  #define LOCAL_IP_ADDR(addr)						  \
  	(((addr) & 0xff000000) == 0x0a000000		/* 10.x.x.x */	  \
  	 || ((addr) & 0xfff00000) == 0xac100000		/* 172.16.x.x */  \
  	 || ((addr) & 0xffff0000) == 0xc0a80000)	/* 192.168.x.x */
  
  #define process_exists(n)	(kill((n), 0) == 0 || errno != ESRCH)
  
  void
  mp_check_options()
  {
  	lcp_options *wo = &lcp_wantoptions[0];
  	lcp_options *ao = &lcp_allowoptions[0];
  
  	doing_multilink = 0;
  	if (!multilink)
  		return;
  	/* if we're doing multilink, we have to negotiate MRRU */
  	if (!wo->neg_mrru) {
  		/* mrru not specified, default to mru */
  		wo->mrru = wo->mru;
  		wo->neg_mrru = 1;
  	}
  	ao->mrru = ao->mru;
  	ao->neg_mrru = 1;
  
  	if (!wo->neg_endpoint && !noendpoint) {
  		/* get a default endpoint value */
  		wo->neg_endpoint = get_default_epdisc(&wo->endpoint);
  	}
  }
  
  /*
   * Make a new bundle or join us to an existing bundle
   * if we are doing multilink.
   */
  int
  mp_join_bundle()
  {
  	lcp_options *go = &lcp_gotoptions[0];
  	lcp_options *ho = &lcp_hisoptions[0];
  	lcp_options *ao = &lcp_allowoptions[0];
  	int unit, pppd_pid;
  	int l, mtu;
  	char *p;
  	TDB_DATA key, pid, rec;
  
  	if (doing_multilink) {
  		/* have previously joined a bundle */
  		if (!go->neg_mrru || !ho->neg_mrru) {
  			notice("oops, didn't get multilink on renegotiation");
  			lcp_close(pcb, "multilink required");
  			return 0;
  		}
  		/* XXX should check the peer_authname and ho->endpoint
  		   are the same as previously */
  		return 0;
  	}
  
  	if (!go->neg_mrru || !ho->neg_mrru) {
  		/* not doing multilink */
  		if (go->neg_mrru)
  			notice("oops, multilink negotiated only for receive");
  		mtu = ho->neg_mru? ho->mru: PPP_MRU;
  		if (mtu > ao->mru)
  			mtu = ao->mru;
  		if (demand) {
  			/* already have a bundle */
  			cfg_bundle(0, 0, 0, 0);
  			netif_set_mtu(pcb, mtu);
  			return 0;
  		}
  		make_new_bundle(0, 0, 0, 0);
  		set_ifunit(1);
  		netif_set_mtu(pcb, mtu);
  		return 0;
  	}
  
  	doing_multilink = 1;
  
  	/*
  	 * Find the appropriate bundle or join a new one.
  	 * First we make up a name for the bundle.
  	 * The length estimate is worst-case assuming every
  	 * character has to be quoted.
  	 */
  	l = 4 * strlen(peer_authname) + 10;
  	if (ho->neg_endpoint)
  		l += 3 * ho->endpoint.length + 8;
  	if (bundle_name)
  		l += 3 * strlen(bundle_name) + 2;
  	bundle_id = malloc(l);
  	if (bundle_id == 0)
  		novm("bundle identifier");
  
  	p = bundle_id;
  	p += slprintf(p, l-1, "BUNDLE=\"%q\"", peer_authname);
  	if (ho->neg_endpoint || bundle_name)
  		*p++ = '/';
  	if (ho->neg_endpoint)
  		p += slprintf(p, bundle_id+l-p, "%s",
  			      epdisc_to_str(&ho->endpoint));
  	if (bundle_name)
  		p += slprintf(p, bundle_id+l-p, "/%v", bundle_name);
  
  	/* Make the key for the list of links belonging to the bundle */
  	l = p - bundle_id;
  	blinks_id = malloc(l + 7);
  	if (blinks_id == NULL)
  		novm("bundle links key");
  	slprintf(blinks_id, l + 7, "BUNDLE_LINKS=%s", bundle_id + 7);
  
  	/*
  	 * For demand mode, we only need to configure the bundle
  	 * and attach the link.
  	 */
  	mtu = LWIP_MIN(ho->mrru, ao->mru);
  	if (demand) {
  		cfg_bundle(go->mrru, ho->mrru, go->neg_ssnhf, ho->neg_ssnhf);
  		netif_set_mtu(pcb, mtu);
  		script_setenv("BUNDLE", bundle_id + 7, 1);
  		return 0;
  	}
  
  	/*
  	 * Check if the bundle ID is already in the database.
  	 */
  	unit = -1;
  	lock_db();
  	key.dptr = bundle_id;
  	key.dsize = p - bundle_id;
  	pid = tdb_fetch(pppdb, key);
  	if (pid.dptr != NULL) {
  		/* bundle ID exists, see if the pppd record exists */
  		rec = tdb_fetch(pppdb, pid);
  		if (rec.dptr != NULL && rec.dsize > 0) {
  			/* make sure the string is null-terminated */
  			rec.dptr[rec.dsize-1] = 0;
  			/* parse the interface number */
  			parse_num(rec.dptr, "IFNAME=ppp", &unit);
  			/* check the pid value */
  			if (!parse_num(rec.dptr, "PPPD_PID=", &pppd_pid)
  			    || !process_exists(pppd_pid)
  			    || !owns_unit(pid, unit))
  				unit = -1;
  			free(rec.dptr);
  		}
  		free(pid.dptr);
  	}
  
  	if (unit >= 0) {
  		/* attach to existing unit */
  		if (bundle_attach(unit)) {
  			set_ifunit(0);
  			script_setenv("BUNDLE", bundle_id + 7, 0);
  			make_bundle_links(1);
  			unlock_db();
  			info("Link attached to %s", ifname);
  			return 1;
  		}
  		/* attach failed because bundle doesn't exist */
  	}
  
  	/* we have to make a new bundle */
  	make_new_bundle(go->mrru, ho->mrru, go->neg_ssnhf, ho->neg_ssnhf);
  	set_ifunit(1);
  	netif_set_mtu(pcb, mtu);
  	script_setenv("BUNDLE", bundle_id + 7, 1);
  	make_bundle_links(pcb);
  	unlock_db();
  	info("New bundle %s created", ifname);
  	multilink_master = 1;
  	return 0;
  }
  
  void mp_exit_bundle()
  {
  	lock_db();
  	remove_bundle_link();
  	unlock_db();
  }
  
  static void sendhup(char *str)
  {
  	int pid;
  
  	if (parse_num(str, "PPPD_PID=", &pid) && pid != getpid()) {
  		if (debug)
  			dbglog("sending SIGHUP to process %d", pid);
  		kill(pid, SIGHUP);
  	}
  }
  
  void mp_bundle_terminated()
  {
  	TDB_DATA key;
  
  	bundle_terminating = 1;
  	upper_layers_down(pcb);
  	notice("Connection terminated.");
  #if PPP_STATS_SUPPORT
  	print_link_stats();
  #endif /* PPP_STATS_SUPPORT */
  	if (!demand) {
  		remove_pidfiles();
  		script_unsetenv("IFNAME");
  	}
  
  	lock_db();
  	destroy_bundle();
  	iterate_bundle_links(sendhup);
  	key.dptr = blinks_id;
  	key.dsize = strlen(blinks_id);
  	tdb_delete(pppdb, key);
  	unlock_db();
  
  	new_phase(PPP_PHASE_DEAD);
  
  	doing_multilink = 0;
  	multilink_master = 0;
  }
  
  static void make_bundle_links(int append)
  {
  	TDB_DATA key, rec;
  	char *p;
  	char entry[32];
  	int l;
  
  	key.dptr = blinks_id;
  	key.dsize = strlen(blinks_id);
  	slprintf(entry, sizeof(entry), "%s;", db_key);
  	p = entry;
  	if (append) {
  		rec = tdb_fetch(pppdb, key);
  		if (rec.dptr != NULL && rec.dsize > 0) {
  			rec.dptr[rec.dsize-1] = 0;
  			if (strstr(rec.dptr, db_key) != NULL) {
  				/* already in there? strange */
  				warn("link entry already exists in tdb");
  				return;
  			}
  			l = rec.dsize + strlen(entry);
  			p = malloc(l);
  			if (p == NULL)
  				novm("bundle link list");
  			slprintf(p, l, "%s%s", rec.dptr, entry);
  		} else {
  			warn("bundle link list not found");
  		}
  		if (rec.dptr != NULL)
  			free(rec.dptr);
  	}
  	rec.dptr = p;
  	rec.dsize = strlen(p) + 1;
  	if (tdb_store(pppdb, key, rec, TDB_REPLACE))
  		error("couldn't %s bundle link list",
  		      append? "update": "create");
  	if (p != entry)
  		free(p);
  }
  
  static void remove_bundle_link()
  {
  	TDB_DATA key, rec;
  	char entry[32];
  	char *p, *q;
  	int l;
  
  	key.dptr = blinks_id;
  	key.dsize = strlen(blinks_id);
  	slprintf(entry, sizeof(entry), "%s;", db_key);
  
  	rec = tdb_fetch(pppdb, key);
  	if (rec.dptr == NULL || rec.dsize <= 0) {
  		if (rec.dptr != NULL)
  			free(rec.dptr);
  		return;
  	}
  	rec.dptr[rec.dsize-1] = 0;
  	p = strstr(rec.dptr, entry);
  	if (p != NULL) {
  		q = p + strlen(entry);
  		l = strlen(q) + 1;
  		memmove(p, q, l);
  		rec.dsize = p - rec.dptr + l;
  		if (tdb_store(pppdb, key, rec, TDB_REPLACE))
  			error("couldn't update bundle link list (removal)");
  	}
  	free(rec.dptr);
  }
  
  static void iterate_bundle_links(void (*func)(char *))
  {
  	TDB_DATA key, rec, pp;
  	char *p, *q;
  
  	key.dptr = blinks_id;
  	key.dsize = strlen(blinks_id);
  	rec = tdb_fetch(pppdb, key);
  	if (rec.dptr == NULL || rec.dsize <= 0) {
  		error("bundle link list not found (iterating list)");
  		if (rec.dptr != NULL)
  			free(rec.dptr);
  		return;
  	}
  	p = rec.dptr;
  	p[rec.dsize-1] = 0;
  	while ((q = strchr(p, ';')) != NULL) {
  		*q = 0;
  		key.dptr = p;
  		key.dsize = q - p;
  		pp = tdb_fetch(pppdb, key);
  		if (pp.dptr != NULL && pp.dsize > 0) {
  			pp.dptr[pp.dsize-1] = 0;
  			func(pp.dptr);
  		}
  		if (pp.dptr != NULL)
  			free(pp.dptr);
  		p = q + 1;
  	}
  	free(rec.dptr);
  }
  
  static int
  parse_num(str, key, valp)
       char *str;
       const char *key;
       int *valp;
  {
  	char *p, *endp;
  	int i;
  
  	p = strstr(str, key);
  	if (p != 0) {
  		p += strlen(key);
  		i = strtol(p, &endp, 10);
  		if (endp != p && (*endp == 0 || *endp == ';')) {
  			*valp = i;
  			return 1;
  		}
  	}
  	return 0;
  }
  
  /*
   * Check whether the pppd identified by `key' still owns ppp unit `unit'.
   */
  static int
  owns_unit(key, unit)
       TDB_DATA key;
       int unit;
  {
  	char ifkey[32];
  	TDB_DATA kd, vd;
  	int ret = 0;
  
  	slprintf(ifkey, sizeof(ifkey), "IFNAME=ppp%d", unit);
  	kd.dptr = ifkey;
  	kd.dsize = strlen(ifkey);
  	vd = tdb_fetch(pppdb, kd);
  	if (vd.dptr != NULL) {
  		ret = vd.dsize == key.dsize
  			&& memcmp(vd.dptr, key.dptr, vd.dsize) == 0;
  		free(vd.dptr);
  	}
  	return ret;
  }
  
  static int
  get_default_epdisc(ep)
       struct epdisc *ep;
  {
  	char *p;
  	struct hostent *hp;
  	u32_t addr;
  
  	/* First try for an ethernet MAC address */
  	p = get_first_ethernet();
  	if (p != 0 && get_if_hwaddr(ep->value, p) >= 0) {
  		ep->class = EPD_MAC;
  		ep->length = 6;
  		return 1;
  	}
  
  	/* see if our hostname corresponds to a reasonable IP address */
  	hp = gethostbyname(hostname);
  	if (hp != NULL) {
  		addr = *(u32_t *)hp->h_addr;
  		if (!bad_ip_adrs(addr)) {
  			addr = ntohl(addr);
  			if (!LOCAL_IP_ADDR(addr)) {
  				ep->class = EPD_IP;
  				set_ip_epdisc(ep, addr);
  				return 1;
  			}
  		}
  	}
  
  	return 0;
  }
  
  /*
   * epdisc_to_str - make a printable string from an endpoint discriminator.
   */
  
  static char *endp_class_names[] = {
      "null", "local", "IP", "MAC", "magic", "phone"
  };
  
  char *
  epdisc_to_str(ep)
       struct epdisc *ep;
  {
  	static char str[MAX_ENDP_LEN*3+8];
  	u_char *p = ep->value;
  	int i, mask = 0;
  	char *q, c, c2;
  
  	if (ep->class == EPD_NULL && ep->length == 0)
  		return "null";
  	if (ep->class == EPD_IP && ep->length == 4) {
  		u32_t addr;
  
  		GETLONG(addr, p);
  		slprintf(str, sizeof(str), "IP:%I", htonl(addr));
  		return str;
  	}
  
  	c = ':';
  	c2 = '.';
  	if (ep->class == EPD_MAC && ep->length == 6)
  		c2 = ':';
  	else if (ep->class == EPD_MAGIC && (ep->length % 4) == 0)
  		mask = 3;
  	q = str;
  	if (ep->class <= EPD_PHONENUM)
  		q += slprintf(q, sizeof(str)-1, "%s",
  			      endp_class_names[ep->class]);
  	else
  		q += slprintf(q, sizeof(str)-1, "%d", ep->class);
  	c = ':';
  	for (i = 0; i < ep->length && i < MAX_ENDP_LEN; ++i) {
  		if ((i & mask) == 0) {
  			*q++ = c;
  			c = c2;
  		}
  		q += slprintf(q, str + sizeof(str) - q, "%.2x", ep->value[i]);
  	}
  	return str;
  }
  
  static int hexc_val(int c)
  {
  	if (c >= 'a')
  		return c - 'a' + 10;
  	if (c >= 'A')
  		return c - 'A' + 10;
  	return c - '0';
  }
  
  int
  str_to_epdisc(ep, str)
       struct epdisc *ep;
       char *str;
  {
  	int i, l;
  	char *p, *endp;
  
  	for (i = EPD_NULL; i <= EPD_PHONENUM; ++i) {
  		int sl = strlen(endp_class_names[i]);
  		if (strncasecmp(str, endp_class_names[i], sl) == 0) {
  			str += sl;
  			break;
  		}
  	}
  	if (i > EPD_PHONENUM) {
  		/* not a class name, try a decimal class number */
  		i = strtol(str, &endp, 10);
  		if (endp == str)
  			return 0;	/* can't parse class number */
  		str = endp;
  	}
  	ep->class = i;
  	if (*str == 0) {
  		ep->length = 0;
  		return 1;
  	}
  	if (*str != ':' && *str != '.')
  		return 0;
  	++str;
  
  	if (i == EPD_IP) {
  		u32_t addr;
  		i = parse_dotted_ip(str, &addr);
  		if (i == 0 || str[i] != 0)
  			return 0;
  		set_ip_epdisc(ep, addr);
  		return 1;
  	}
  	if (i == EPD_MAC && get_if_hwaddr(ep->value, str) >= 0) {
  		ep->length = 6;
  		return 1;
  	}
  
  	p = str;
  	for (l = 0; l < MAX_ENDP_LEN; ++l) {
  		if (*str == 0)
  			break;
  		if (p <= str)
  			for (p = str; isxdigit(*p); ++p)
  				;
  		i = p - str;
  		if (i == 0)
  			return 0;
  		ep->value[l] = hexc_val(*str++);
  		if ((i & 1) == 0)
  			ep->value[l] = (ep->value[l] << 4) + hexc_val(*str++);
  		if (*str == ':' || *str == '.')
  			++str;
  	}
  	if (*str != 0 || (ep->class == EPD_MAC && l != 6))
  		return 0;
  	ep->length = l;
  	return 1;
  }
  
  #endif /* PPP_SUPPORT && HAVE_MULTILINK */
  
  