NetBSD/usr.sbin/pim6dd/config.c

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/* $NetBSD: config.c,v 1.4 2000/12/04 07:05:47 itojun Exp $ */
/* $KAME: config.c,v 1.7 2000/12/04 06:33:09 itojun Exp $ */
/*
* Copyright (c) 1998 by the University of Southern California.
* All rights reserved.
*
* Permission to use, copy, modify, and distribute this software and
* its documentation in source and binary forms for lawful
* purposes and without fee is hereby granted, provided
* that the above copyright notice appear in all copies and that both
* the copyright notice and this permission notice appear in supporting
* documentation, and that any documentation, advertising materials,
* and other materials related to such distribution and use acknowledge
* that the software was developed by the University of Southern
* California and/or Information Sciences Institute.
* The name of the University of Southern California may not
* be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THE UNIVERSITY OF SOUTHERN CALIFORNIA DOES NOT MAKE ANY REPRESENTATIONS
* ABOUT THE SUITABILITY OF THIS SOFTWARE FOR ANY PURPOSE. THIS SOFTWARE IS
* PROVIDED "AS IS" AND WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES,
* INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, TITLE, AND
* NON-INFRINGEMENT.
*
* IN NO EVENT SHALL USC, OR ANY OTHER CONTRIBUTOR BE LIABLE FOR ANY
* SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES, WHETHER IN CONTRACT,
* TORT, OR OTHER FORM OF ACTION, ARISING OUT OF OR IN CONNECTION WITH,
* THE USE OR PERFORMANCE OF THIS SOFTWARE.
*
* Other copyrights might apply to parts of this software and are so
* noted when applicable.
*/
/*
* Questions concerning this software should be directed to
* Pavlin Ivanov Radoslavov (pavlin@catarina.usc.edu)
*/
/*
* Part of this program has been derived from mrouted.
* The mrouted program is covered by the license in the accompanying file
* named "LICENSE.mrouted".
*
* The mrouted program is COPYRIGHT 1989 by The Board of Trustees of
* Leland Stanford Junior University.
*
*/
#include "defs.h"
#ifdef HAVE_GETIFADDRS
#include <ifaddrs.h>
#endif
/*
* Forward declarations.
*/
static char *next_word __P((char **));
static int parse_phyint __P((char *s));
static void add_phaddr __P((struct uvif *v, struct sockaddr_in6 *addr,
struct in6_addr *mask));
static mifi_t ifname2mifi __P((char *ifname));
static int wordToOption __P((char *));
static int parse_filter __P((char *s));
#if 0 /* not used */
static int parse_default_source_metric __P((char *));
static int parse_default_source_preference __P((char *));
#endif
/*
* Query the kernel to find network interfaces that are multicast-capable
* and install them in the uvifs array.
*/
void
config_vifs_from_kernel()
{
register struct uvif *v;
register vifi_t vifi;
struct sockaddr_in6 addr;
struct in6_addr mask, prefix;
short flags;
#ifdef HAVE_GETIFADDRS
struct ifaddrs *ifap, *ifa;
#else
int n;
int num_ifreq = 64;
struct ifconf ifc;
struct ifreq *ifrp, *ifend;
#endif
total_interfaces = 0; /* The total number of physical interfaces */
#ifdef HAVE_GETIFADDRS
if (getifaddrs(&ifap))
log(LOG_ERR, errno, "getiaddrs");
/*
* Loop through all of the interfaces.
*/
for (ifa = ifap; ifa; ifa = ifa->ifa_next) {
/*
* Ignore any interface for an address family other than IPv6.
*/
if (ifa->ifa_addr->sa_family != AF_INET6) {
total_interfaces++; /* Eventually may have IPv6 address later */
continue;
}
memcpy(&addr, ifa->ifa_addr, sizeof(struct sockaddr_in6));
flags = ifa->ifa_flags;
if ((flags & (IFF_LOOPBACK | IFF_MULTICAST)) != IFF_MULTICAST)
continue;
/*
* Get netmask of the address.
*/
memcpy(&mask, &((struct sockaddr_in6 *)ifa->ifa_netmask)->sin6_addr,
sizeof(mask));
if (IN6_IS_ADDR_LINKLOCAL(&addr.sin6_addr)) {
addr.sin6_scope_id = if_nametoindex(ifa->ifa_name);
#ifdef __KAME__
/*
* Hack for KAME kernel. Set sin6_scope_id field of a
* link local address and clear the index embedded in
* the address.
*/
/* clear interface index */
addr.sin6_addr.s6_addr[2] = 0;
addr.sin6_addr.s6_addr[3] = 0;
#endif
}
/*
* If the address is connected to the same subnet as one already
* installed in the uvifs array, just add the address to the list
* of addresses of the uvif.
*/
for (vifi = 0, v = uvifs; vifi < numvifs; ++vifi, ++v) {
if (strcmp(v->uv_name, ifa->ifa_name) == 0) {
add_phaddr(v, &addr, &mask);
break;
}
}
if (vifi != numvifs)
continue;
/*
* If there is room in the uvifs array, install this interface.
*/
if (numvifs == MAXMIFS) {
log(LOG_WARNING, 0, "too many ifs, ignoring %s", ifa->ifa_name);
continue;
}
/*
* Everyone below is a potential vif interface.
* We don't care if it has wrong configuration or not configured
* at all.
*/
total_interfaces++;
v = &uvifs[numvifs];
v->uv_flags = 0;
v->uv_metric = DEFAULT_METRIC;
v->uv_admetric = 0;
v->uv_rate_limit = DEFAULT_PHY_RATE_LIMIT;
v->uv_dst_addr = allpim6routers_group;
v->uv_prefix.sin6_addr = prefix;
v->uv_subnetmask = mask;
strncpy(v->uv_name, ifa->ifa_name, IFNAMSIZ);
v->uv_ifindex = if_nametoindex(v->uv_name);
v->uv_groups = (struct listaddr *)NULL;
v->uv_dvmrp_neighbors = (struct listaddr *)NULL;
NBRM_CLRALL(v->uv_nbrmap);
v->uv_querier = (struct listaddr *)NULL;
v->uv_prune_lifetime = 0;
v->uv_acl = (struct vif_acl *)NULL;
v->uv_leaf_timer = 0;
v->uv_addrs = (struct phaddr *)NULL;
v->uv_filter = (struct vif_filter *)NULL;
v->uv_pim_hello_timer = 0;
v->uv_gq_timer = 0;
v->uv_pim_neighbors = (struct pim_nbr_entry *)NULL;
v->uv_local_pref = default_source_preference;
v->uv_local_metric = default_source_metric;
add_phaddr(v, &addr, &mask);
if (flags & IFF_POINTOPOINT)
v->uv_flags |= (VIFF_REXMIT_PRUNES | VIFF_POINT_TO_POINT);
log(LOG_INFO, 0,
"installing %s as if #%u - rate=%d",
v->uv_name, numvifs, v->uv_rate_limit);
++numvifs;
/*
* If the interface is not yet up, set the vifs_down flag to
* remind us to check again later.
*/
if (!(flags & IFF_UP)) {
v->uv_flags |= VIFF_DOWN;
vifs_down = TRUE;
}
}
freeifaddrs(ifap);
#else /* !HAVE_GETIFADDRS */
ifc.ifc_len = num_ifreq * sizeof(struct ifreq);
ifc.ifc_buf = calloc(ifc.ifc_len, sizeof(char));
while (ifc.ifc_buf) {
caddr_t newbuf;
if (ioctl(udp_socket, SIOCGIFCONF, (char *)&ifc) < 0)
log(LOG_ERR, errno, "ioctl SIOCGIFCONF");
/*
* If the buffer was large enough to hold all the addresses
* then break out, otherwise increase the buffer size and
* try again.
*
* The only way to know that we definitely had enough space
* is to know that there was enough space for at least one
* more struct ifreq. ???
*/
if ((num_ifreq * sizeof(struct ifreq)) >=
ifc.ifc_len + sizeof(struct ifreq))
break;
num_ifreq *= 2;
ifc.ifc_len = num_ifreq * sizeof(struct ifreq);
newbuf = realloc(ifc.ifc_buf, ifc.ifc_len);
if (newbuf == NULL)
free(ifc.ifc_buf);
ifc.ifc_buf = newbuf;
}
if (ifc.ifc_buf == NULL)
log(LOG_ERR, 0, "config_vifs_from_kernel: ran out of memory");
ifrp = (struct ifreq *)ifc.ifc_buf;
ifend = (struct ifreq *)(ifc.ifc_buf + ifc.ifc_len);
/*
* Loop through all of the interfaces.
*/
for (; ifrp < ifend; ifrp = (struct ifreq *)((char *)ifrp + n)) {
struct ifreq ifr;
struct in6_ifreq ifr6;
#ifdef HAVE_SA_LEN
n = ifrp->ifr_addr.sa_len + sizeof(ifrp->ifr_name);
if (n < sizeof(*ifrp))
n = sizeof(*ifrp);
#else
n = sizeof(*ifrp);
#endif /* HAVE_SA_LEN */
/*
* Ignore any interface for an address family other than IPv6.
*/
if (ifrp->ifr_addr.sa_family != AF_INET6) {
total_interfaces++; /* Eventually may have IPv6 address later */
continue;
}
memcpy(&addr, &ifrp->ifr_addr, sizeof(struct sockaddr_in6));
/*
* Need a template to preserve address info that is
* used below to locate the next entry. (Otherwise,
* SIOCGIFFLAGS stomps over it because the requests
* are returned in a union.)
*/
memcpy(ifr.ifr_name, ifrp->ifr_name, sizeof(ifr.ifr_name));
memcpy(ifr6.ifr_name, ifrp->ifr_name, sizeof(ifr6.ifr_name));
/*
* Ignore loopback interfaces and interfaces that do not
* support multicast.
*/
if (ioctl(udp_socket, SIOCGIFFLAGS, (char *)&ifr) < 0)
log(LOG_ERR, errno, "ioctl SIOCGIFFLAGS for %s", ifr.ifr_name);
flags = ifr.ifr_flags;
if ((flags & (IFF_LOOPBACK | IFF_MULTICAST)) != IFF_MULTICAST)
continue;
/*
* Get netmask of the address.
*/
ifr6.ifr_addr = *(struct sockaddr_in6 *)&ifrp->ifr_addr;
if (ioctl(udp_socket, SIOCGIFNETMASK_IN6, (char *)&ifr6) < 0)
log(LOG_ERR, errno, "ioctl SIOCGIFNETMASK_IN6 for %s",
ifr6.ifr_name);
memcpy(&mask, &ifr6.ifr_addr.sin6_addr, sizeof(mask));
if (IN6_IS_ADDR_LINKLOCAL(&addr.sin6_addr)) {
addr.sin6_scope_id = if_nametoindex(ifrp->ifr_name);
#ifdef __KAME__
/*
* Hack for KAME kernel. Set sin6_scope_id field of a
* link local address and clear the index embedded in
* the address.
*/
/* clear interface index */
addr.sin6_addr.s6_addr[2] = 0;
addr.sin6_addr.s6_addr[3] = 0;
#endif
}
/*
* If the address is connected to the same subnet as one already
* installed in the uvifs array, just add the address to the list
* of addresses of the uvif.
*/
for (vifi = 0, v = uvifs; vifi < numvifs; ++vifi, ++v) {
if (strcmp(v->uv_name, ifr.ifr_name) == 0) {
add_phaddr(v, &addr, &mask);
break;
}
}
if (vifi != numvifs)
continue;
/*
* If there is room in the uvifs array, install this interface.
*/
if (numvifs == MAXMIFS) {
log(LOG_WARNING, 0, "too many ifs, ignoring %s", ifr.ifr_name);
continue;
}
/*
* Everyone below is a potential vif interface.
* We don't care if it has wrong configuration or not configured
* at all.
*/
total_interfaces++;
v = &uvifs[numvifs];
v->uv_flags = 0;
v->uv_metric = DEFAULT_METRIC;
v->uv_admetric = 0;
v->uv_rate_limit = DEFAULT_PHY_RATE_LIMIT;
v->uv_dst_addr = allpim6routers_group;
v->uv_prefix.sin6_addr = prefix;
v->uv_subnetmask = mask;
strncpy(v->uv_name, ifr.ifr_name, IFNAMSIZ);
v->uv_ifindex = if_nametoindex(v->uv_name);
v->uv_groups = (struct listaddr *)NULL;
v->uv_dvmrp_neighbors = (struct listaddr *)NULL;
NBRM_CLRALL(v->uv_nbrmap);
v->uv_querier = (struct listaddr *)NULL;
v->uv_prune_lifetime = 0;
v->uv_acl = (struct vif_acl *)NULL;
v->uv_leaf_timer = 0;
v->uv_addrs = (struct phaddr *)NULL;
v->uv_filter = (struct vif_filter *)NULL;
v->uv_pim_hello_timer = 0;
v->uv_gq_timer = 0;
v->uv_pim_neighbors = (struct pim_nbr_entry *)NULL;
v->uv_local_pref = default_source_preference;
v->uv_local_metric = default_source_metric;
add_phaddr(v, &addr, &mask);
if (flags & IFF_POINTOPOINT)
v->uv_flags |= (VIFF_REXMIT_PRUNES | VIFF_POINT_TO_POINT);
log(LOG_INFO, 0,
"installing %s as if #%u - rate=%d",
v->uv_name, numvifs, v->uv_rate_limit);
++numvifs;
/*
* If the interface is not yet up, set the vifs_down flag to
* remind us to check again later.
*/
if (!(flags & IFF_UP)) {
v->uv_flags |= VIFF_DOWN;
vifs_down = TRUE;
}
}
#endif /* HAVE_GETIFADDRS */
}
static void
add_phaddr(v, addr, mask)
struct uvif *v;
struct sockaddr_in6 *addr;
struct in6_addr *mask;
{
struct phaddr *pa;
int i;
if ((pa = malloc(sizeof(*pa))) == NULL)
log(LOG_ERR, 0, "add_phaddr: memory exhausted");
memset(pa, 0, sizeof(*pa));
pa->pa_addr = *addr;
pa->pa_subnetmask = *mask;
/*
* install the prefix of the address derived from the address
* and the mask.
*/
for (i = 0; i < sizeof(struct in6_addr); i++)
pa->pa_prefix.sin6_addr.s6_addr[i] =
addr->sin6_addr.s6_addr[i] & mask->s6_addr[i];
pa->pa_prefix.sin6_scope_id = addr->sin6_scope_id;
if (IN6_IS_ADDR_LINKLOCAL(&addr->sin6_addr)) {
if (v->uv_linklocal) {
log(LOG_WARNING, 0,
"add_phaddr: found more than one link-local "
"address on %s",
v->uv_name);
}
v->uv_linklocal = pa; /* relace anyway */
}
/* link into chain */
pa->pa_next = v->uv_addrs;
v->uv_addrs = pa;
}
static mifi_t
ifname2mifi(ifname)
char *ifname;
{
mifi_t mifi;
struct uvif *v;
for (mifi = 0, v = uvifs; mifi < numvifs; ++mifi, ++v) {
if (strcmp(v->uv_name, ifname) == 0)
break;
}
return(mifi);
}
#define UNKNOWN -1
#define EMPTY 1
#define PHYINT 2
#define DEFAULT_SOURCE_METRIC 3
#define DEFAULT_SOURCE_PREFERENCE 4
#define FILTER 5
/*
* function name: wordToOption
* input: char *word, a pointer to the word
* output: int; a number corresponding to the code of the word
* operation: converts the result of the string comparisons into numerics.
* comments: called by config_vifs_from_file()
*/
static int
wordToOption(word)
char *word;
{
if (EQUAL(word, ""))
return EMPTY;
if (EQUAL(word, "phyint"))
return PHYINT;
if (EQUAL(word, "default_source_metric"))
return DEFAULT_SOURCE_METRIC;
if (EQUAL(word, "default_source_preference"))
return DEFAULT_SOURCE_PREFERENCE;
if (EQUAL(word, "filter"))
return FILTER;
return UNKNOWN;
}
/*
* function name: parse_phyint
* input: char *s, pointing to the parsing point of the file
* output: int (TRUE if the parsing was successful, o.w. FALSE)
* operation: parses the physical interface file configurations, if any.
* The general form is:
* phyint <ifname> [disable]
*/
static int
parse_phyint(s)
char *s;
{
char *w, c, *ifname;
vifi_t vifi;
struct uvif *v;
u_int n;
if (EQUAL((w = next_word(&s)), "")) {
log(LOG_WARNING, 0, "Missing phyint in %s", configfilename);
return(FALSE);
} /* if empty */
ifname = w;
for (vifi = 0, v = uvifs; vifi < numvifs; ++vifi, ++v) {
if (vifi == numvifs) {
log(LOG_WARNING, 0,
"phyint %s in %s is not a configured interface",
ifname, configfilename);
return(FALSE);
} /* if vifi == numvifs */
if (strcmp(v->uv_name, ifname))
continue;
while (!EQUAL((w = next_word(&s)), "")) {
if (EQUAL(w, "disable"))
v->uv_flags |= VIFF_DISABLED;
else if (EQUAL(w, "nolistener"))
v->uv_flags |= VIFF_NOLISTENER;
else if(EQUAL(w, "preference")) {
if(EQUAL((w = next_word(&s)), ""))
log(LOG_WARNING, 0,
"Missing preference for phyint %s in %s",
ifname, configfilename);
else if (sscanf(w, "%u%c", &n, &c) != 1 ||
n < 1 || n > 255 )
log(LOG_WARNING, 0,
"Invalid preference '%s' for phyint %s in %s",
w, ifname,
configfilename);
else {
IF_DEBUG(DEBUG_ASSERT)
log(LOG_DEBUG, 0,
"Config setting default local preference on %s to %d.",
ifname, n);
v->uv_local_pref = n;
}
} else if(EQUAL(w, "metric")) {
if(EQUAL((w = next_word(&s)), ""))
log(LOG_WARNING, 0,
"Missing metric for phyint %s in %s",
ifname, configfilename);
else if (sscanf(w, "%u%c", &n, &c) != 1 ||
n < 1 || n > 1024 )
log(LOG_WARNING, 0,
"Invalid metric '%s' for phyint %s in %s",
w, ifname,
configfilename);
else {
IF_DEBUG(DEBUG_ASSERT)
log(LOG_DEBUG, 0,
"Config setting default local metric on %s to %d.",
ifname, n);
v->uv_local_metric = n;
}
}
} /* if not empty */
break;
}
return(TRUE);
}
static int
parse_filter(s)
char *s;
{
char *w, *groups, *p;
mifi_t mifi;
struct in6_addr grp1, grp2;
if_set filterset;
struct mrtfilter *filter;
int plen = 0, filtertype;
if (EQUAL((groups = next_word(&s)), "")) {
log(LOG_WARNING, 0, "Missing multicast group in %s",
configfilename);
return(FALSE);
}
/*
* Group address specification. Valid format are the followings.
* - Group1-Group2: specifies a numerical range of a scope.
* - GroupPrefix/Prefixlen: specifies a prefix of a scope. If the
* Prefixlen is omitted, it means the exact match.
*/
if ((p = strchr(groups, '-')) != NULL) { /* Group1-Group2 */
char *maddr1, *maddr2;
maddr1 = groups;
maddr2 = p + 1;
*p = '\0';
if (inet_pton(AF_INET6, maddr1, (void *)&grp1) != 1 ||
!IN6_IS_ADDR_MULTICAST(&grp1)) {
log(LOG_WARNING, 0, "invalid group address %s", maddr1);
return(FALSE);
}
if (inet_pton(AF_INET6, maddr2, (void *)&grp2) != 1 ||
!IN6_IS_ADDR_MULTICAST(&grp2)) {
log(LOG_WARNING, 0, "invalid group address %s", maddr2);
return(FALSE);
}
filtertype = FILTER_RANGE;
}
else if ((p = strchr(groups, '/')) != NULL) { /* GroupPrefix/Plen */
char *mprefix = groups;
int plen = atoi(p + 1);
*p = '\0';
if (inet_pton(AF_INET6, mprefix, (void *)&grp1) != 1 ||
!IN6_IS_ADDR_MULTICAST(&grp1)) {
log(LOG_WARNING, 0, "invalid group prefix %s", mprefix);
return(FALSE);
}
if (plen < 0 || plen > 128) {
log(LOG_WARNING, 0, "invalid prefix length %s", p + 1);
return(FALSE);
}
filtertype = FILTER_PREFIX;
}
else {
if (inet_pton(AF_INET6, groups, (void *)&grp1) != 1) {
log(LOG_WARNING, 0, "invalid group address %s", groups);
return(FALSE);
}
plen = 128; /* exact match */
filtertype = FILTER_PREFIX;
}
IF_ZERO(&filterset);
while (!EQUAL((w = next_word(&s)), "")) {
if ((mifi = ifname2mifi(w)) == MAXMIFS) {
/* XXX: scope consideration?? */
log(LOG_WARNING, 0,
"phyint %s in %s is not a configured interface",
w, configfilename);
return(FALSE);
}
IF_SET(mifi, &filterset);
}
if (IF_ISEMPTY(&filterset)) {
log(LOG_WARNING, 0,
"filter set is empty. ignore it.");
return(FALSE);
}
filter = add_filter(filtertype, &grp1, &grp2, plen);
IF_COPY(&filterset, &filter->ifset);
return(TRUE);
}
#if 0 /* not used */
/*
* function name: parse_default_source_metric
* input: char *s
* output: int
* operation: reads and assigns the default source metric, if no reliable
* unicast routing information available.
* General form:
* 'default_source_metric <number>'.
* default pref and metric statements should precede all phyint
* statements in the config file.
*/
static int
parse_default_source_metric(s)
char *s;
{
char *w;
u_int value;
vifi_t vifi;
struct uvif *v;
value = DEFAULT_LOCAL_METRIC;
if (EQUAL((w = next_word(&s)), "")) {
log(LOG_WARNING, 0,
"Missing default source metric; set to default %u",
DEFAULT_LOCAL_METRIC);
} else if (sscanf(w, "%u", &value) != 1) {
log(LOG_WARNING, 0,
"Invalid default source metric; set to default %u",
DEFAULT_LOCAL_METRIC);
value = DEFAULT_LOCAL_METRIC;
}
default_source_metric = value;
log(LOG_INFO, 0, "default_source_metric is %u", value);
for (vifi = 0, v = uvifs; vifi < MAXMIFS; ++vifi, ++v) {
v->uv_local_metric = default_source_metric;
}
return(TRUE);
}
/*
* function name: parse_default_source_preference
* input: char *s
* output: int
* operation: reads and assigns the default source preference, if no reliable
* unicast routing information available.
* General form:
* 'default_source_preference <number>'.
* default pref and metric statements should precede all phyint
* statements in the config file.
*/
static int
parse_default_source_preference(s)
char *s;
{
char *w;
u_int value;
vifi_t vifi;
struct uvif *v;
value = DEFAULT_LOCAL_PREF;
if (EQUAL((w = next_word(&s)), "")) {
log(LOG_WARNING, 0,
"Missing default source preference; set to default %u",
DEFAULT_LOCAL_PREF);
} else if (sscanf(w, "%u", &value) != 1) {
log(LOG_WARNING, 0,
"Invalid default source preference; set to default %u",
DEFAULT_LOCAL_PREF);
value = DEFAULT_LOCAL_PREF;
}
default_source_preference = value;
log(LOG_INFO, 0, "default_source_preference is %u", value);
for (vifi = 0, v = uvifs; vifi < MAXMIFS; ++vifi, ++v) {
v->uv_local_pref = default_source_preference;
}
return(TRUE);
}
#endif
void
config_vifs_from_file()
{
FILE *f;
char linebuf[100];
char *w, *s;
int option;
if ((f = fopen(configfilename, "r")) == NULL) {
if (errno != ENOENT) log(LOG_WARNING, errno, "can't open %s",
configfilename);
return;
}
while (fgets(linebuf, sizeof(linebuf), f) != NULL) {
s = linebuf;
w = next_word(&s);
option = wordToOption(w);
switch(option) {
case EMPTY:
continue;
break;
case PHYINT:
parse_phyint(s);
break;
case FILTER:
parse_filter(s);
break;
default:
log(LOG_WARNING, 0, "unknown command '%s' in %s",
w, configfilename);
}
}
fclose(f);
}
static char *
next_word(s)
char **s;
{
char *w;
w = *s;
while (*w == ' ' || *w == '\t')
w++;
*s = w;
for(;;) {
switch (**s) {
case ' ' :
case '\t' :
**s = '\0';
(*s)++;
return(w);
case '\n' :
case '#' :
**s = '\0';
return(w);
case '\0' :
return(w);
default :
if (isascii(**s) && isupper(**s))
**s = tolower(**s);
(*s)++;
}
}
}