+++ /dev/null
-/*
- * nss-icmp or libnss_icmp - GNU C Library NSS module to query host
- * names by ICMP.
- * Copyright (C) 2005 Fredrik Tolf <fredrik@dolda2000.com>
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Library General Public
- * License as published by the Free Software Foundation; either
- * version 2 of the License, or (at your option) any later version.
- *
- * This library 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
- * Library General Public License for more details.
- *
- * You should have received a copy of the GNU Library General Public
- * License along with this library; if not, write to the Free
- * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
- * MA 02111-1307, USA
- */
-
-#include <stdlib.h>
-#include <stdio.h>
-#include <unistd.h>
-#include <string.h>
-#include <errno.h>
-#include <time.h>
-#include <sys/socket.h>
-#include <netinet/in.h>
-#include <netdb.h>
-#include <arpa/inet.h>
-#include <nss.h>
-#include <sys/types.h>
-#include <fcntl.h>
-#include <sys/wait.h>
-
-#define CONFIGFILE "/etc/nss-icmp.conf"
-#if 0
-#define DEBUGP(format...) fprintf(stderr, "nss-icmp: " format);
-#else
-#define DEBUGP(format...)
-#endif
-
-struct cache {
- struct cache *next, *prev;
- char *addr;
- socklen_t addrlen;
- int af;
- int notfound;
- char **names;
- time_t at, ttl;
-};
-
-static int inited = 0;
-static int timeout = -1;
-static int usecache = 1;
-static time_t nfttl = 300;
-static struct cache *cache = NULL;
-
-static void readconfig(void)
-{
- FILE *f;
- char linebuf[1024];
- char *p, *p2;
-
- if((f = fopen(CONFIGFILE, "r")) == NULL)
- return;
-
- while(fgets(linebuf, sizeof(linebuf), f) != NULL) {
- if(linebuf[0] == '#')
- continue;
- if((p = strchr(linebuf, '\n')) != NULL)
- *p = 0;
- if((p = strchr(linebuf, ' ')) != NULL) {
- p2 = p + 1;
- *p = 0;
- }
- if(!strcmp(linebuf, "timeout")) {
- if(p2 == NULL)
- continue;
- timeout = atoi(p2);
- }
- if(!strcmp(linebuf, "ttlnotfound")) {
- if(p2 == NULL)
- continue;
- nfttl = atoi(p2);
- }
- if(!strcmp(linebuf, "nocache")) {
- usecache = 0;
- }
- }
-
- fclose(f);
-}
-
-static void freecache(struct cache *cc)
-{
- int i;
-
- if(cc->next != NULL)
- cc->next->prev = cc->prev;
- if(cc->prev != NULL)
- cc->prev->next = cc->next;
- if(cc == cache)
- cache = cc->next;
- if(cc->addr != NULL)
- free(cc->addr);
- if(cc->names != NULL) {
- for(i = 0; cc->names[i] != NULL; i++)
- free(cc->names[i]);
- free(cc->names);
- }
- free(cc);
-}
-
-static void cachenotfound(const void *addr, socklen_t len, int af, time_t ttl)
-{
- struct cache *cc;
-
- for(cc = cache; cc != NULL; cc = cc->next) {
- if((cc->af == af) && (cc->addrlen == len) && !memcmp(cc->addr, addr, len))
- break;
- }
- if(cc == NULL) {
- if((cc = malloc(sizeof(*cc))) == NULL)
- return;
- memset(cc, 0, sizeof(*cc));
- if((cc->addr = malloc(len)) == NULL) {
- freecache(cc);
- return;
- }
- memcpy(cc->addr, addr, len);
- cc->addrlen = len;
- cc->af = af;
- cc->at = time(NULL);
- cc->ttl = ttl;
-
- cc->notfound = 1;
-
- cc->next = cache;
- if(cache != NULL)
- cache->prev = cc;
- cache = cc;
- }
-}
-
-static void updatecache(const void *addr, socklen_t len, int af, char **names, time_t ttl)
-{
- int i;
- struct cache *cc;
-
- for(cc = cache; cc != NULL; cc = cc->next) {
- if((cc->af == af) && (cc->addrlen == len) && !memcmp(cc->addr, addr, len))
- break;
- }
- if(cc == NULL) {
- if((cc = malloc(sizeof(*cc))) == NULL)
- return;
- memset(cc, 0, sizeof(*cc));
- if((cc->addr = malloc(len)) == NULL) {
- freecache(cc);
- return;
- }
- memcpy(cc->addr, addr, len);
- cc->addrlen = len;
- cc->af = af;
- cc->at = time(NULL);
- cc->ttl = ttl;
-
- for(i = 0; names[i] != NULL; i++);
- if((cc->names = malloc(sizeof(*(cc->names)) * (i + 1))) == NULL) {
- freecache(cc);
- return;
- }
- memset(cc->names, 0, sizeof(*(cc->names)) * (i + 1));
- for(i = 0; names[i] != NULL; i++) {
- if((cc->names[i] = malloc(strlen(names[i]) + 1)) == NULL) {
- freecache(cc);
- return;
- }
- strcpy(cc->names[i], names[i]);
- }
-
- cc->next = cache;
- if(cache != NULL)
- cache->prev = cc;
- cache = cc;
- }
-}
-
-static void expirecache(void)
-{
- struct cache *cc, *next;
- time_t now;
-
- now = time(NULL);
- for(cc = cache; cc != NULL; cc = next) {
- next = cc->next;
- if(now - cc->at > cc->ttl) {
- freecache(cc);
- continue;
- }
- }
-}
-
-enum nss_status _nss_icmp_gethostbyaddr_r(const void *addr, socklen_t len, int af, struct hostent *result, char *buffer, size_t buflen, int *errnop, int *h_errnop)
-{
- int i, ret;
- struct retstruct {
- char *aliaslist[16];
- char *addrlist[2];
- char retaddr[16];
- } *retbuf;
- char addrbuf[1024];
- int an, thislen, ttl;
- char *p, *p2, *p3;
- u_int8_t *ap;
- pid_t child;
- int pfd[2];
- int rl;
- int status;
- struct cache *cc;
-
- if(!inited) {
- readconfig();
- inited = 1;
- }
-
- retbuf = (struct retstruct *)buffer;
- if((buflen < sizeof(*retbuf)) || (len > sizeof(retbuf->retaddr))) {
- *errnop = ENOMEM;
- *h_errnop = NETDB_INTERNAL;
- return(NSS_STATUS_UNAVAIL);
- }
-
- DEBUGP("starting lookup\n");
-
- if(usecache) {
- expirecache();
- for(cc = cache; cc != NULL; cc = cc->next) {
- if((cc->af == af) && (cc->addrlen == len) && !memcmp(cc->addr, addr, len))
- break;
- }
- } else {
- cc = NULL;
- }
-
- if(cc == NULL) {
- DEBUGP("address not in cache, looking up for real\n");
- ap = (u_int8_t *)addr;
- if(inet_ntop(af, addr, addrbuf, sizeof(addrbuf)) == NULL) {
- *errnop = errno;
- *h_errnop = NETDB_INTERNAL;
- return(NSS_STATUS_UNAVAIL);
- }
- DEBUGP("address is %s\n", addrbuf);
-
- if(pipe(pfd)) {
- *errnop = errno;
- *h_errnop = NETDB_INTERNAL;
- return(NSS_STATUS_UNAVAIL);
- }
- /* I honestly don't know if it is considered OK to fork in other
- * people's programs. We need a SUID worker, though, so there's
- * little choice that I can see. */
- if((child = fork()) < 0) {
- *errnop = errno;
- *h_errnop = NETDB_INTERNAL;
- return(NSS_STATUS_UNAVAIL);
- }
-
- if(child == 0) {
- int i, fd;
- char timeoutbuf[128];
-
- if((fd = open("/dev/null", O_WRONLY)) < 0)
- exit(127);
- close(pfd[0]);
- dup2(pfd[1], 1);
- dup2(fd, 2);
- for(i = 3; i < FD_SETSIZE; i++)
- close(i);
-
- if(timeout != -1) {
- snprintf(timeoutbuf, sizeof(timeoutbuf), "%i", timeout);
- execlp("idnlookup", "idnlookup", "-Tt", timeoutbuf, addrbuf, NULL);
- } else {
- execlp("idnlookup", "idnlookup", "-T", addrbuf, NULL);
- }
- exit(127);
- }
-
- close(pfd[1]);
-
- rl = 0;
- do {
- ret = read(pfd[0], addrbuf + rl, sizeof(addrbuf) - rl);
- if(ret < 0) {
- *errnop = errno;
- *h_errnop = NETDB_INTERNAL;
- close(pfd[0]);
- return(NSS_STATUS_UNAVAIL);
- }
- rl += ret;
- if(rl >= sizeof(addrbuf) - 1) {
- *errnop = ENOMEM;
- *h_errnop = NETDB_INTERNAL;
- close(pfd[0]);
- return(NSS_STATUS_UNAVAIL);
- }
- } while(ret != 0);
- addrbuf[rl] = 0;
- close(pfd[0]);
-
- waitpid(child, &status, 0);
-
- if((p = strchr(addrbuf, '\n')) == NULL) {
- if(usecache)
- cachenotfound(addr, len, af, nfttl);
- *h_errnop = TRY_AGAIN; /* XXX: Is this correct? */
- return(NSS_STATUS_NOTFOUND);
- }
- *(p++) = 0;
- ttl = atoi(addrbuf);
-
- an = 0;
- p3 = buffer + sizeof(*retbuf);
- while((p2 = strchr(p, '\n')) != NULL) {
- *p2 = 0;
- thislen = p2 - p;
- if(thislen == 0)
- continue;
- if((p3 - buffer) + thislen + 1 > buflen) {
- *errnop = ENOMEM;
- *h_errnop = NETDB_INTERNAL;
- return(NSS_STATUS_UNAVAIL);
- }
- memcpy(p3, p, thislen + 1);
- retbuf->aliaslist[an] = p3;
- p3 += thislen + 1;
- p = p2 + 1;
- if(++an == 16) {
- *errnop = ENOMEM;
- *h_errnop = NETDB_INTERNAL;
- return(NSS_STATUS_UNAVAIL);
- }
- }
- if(an == 0) {
- if(usecache)
- cachenotfound(addr, len, af, nfttl);
- *h_errnop = TRY_AGAIN; /* XXX: Is this correct? */
- return(NSS_STATUS_NOTFOUND);
- }
- retbuf->aliaslist[an] = NULL;
-
- if(usecache)
- updatecache(addr, len, af, retbuf->aliaslist, ttl);
- } else {
- DEBUGP("address found in cache\n");
- if(cc->notfound) {
- *h_errnop = TRY_AGAIN; /* XXX: Is this correct? */
- return(NSS_STATUS_NOTFOUND);
- }
-
- p3 = buffer + sizeof(*retbuf);
- for(i = 0; cc->names[i] != NULL; i++) {
- thislen = strlen(cc->names[i]);
- DEBUGP("filling in address %s, length %i\n", cc->names[i], thislen);
- if((p3 - buffer) + thislen + 1 > buflen) {
- *errnop = ENOMEM;
- *h_errnop = NETDB_INTERNAL;
- return(NSS_STATUS_UNAVAIL);
- }
- memcpy(p3, cc->names[i], thislen + 1);
- retbuf->aliaslist[i] = p3;
- p3 += thislen + 1;
- }
- retbuf->aliaslist[i] = NULL;
- }
-
- DEBUGP("returning hostent\n");
- memcpy(retbuf->retaddr, addr, len);
- retbuf->addrlist[0] = retbuf->retaddr;
- retbuf->addrlist[1] = NULL;
- result->h_name = retbuf->aliaslist[0];
- result->h_aliases = retbuf->aliaslist;
- result->h_addr_list = retbuf->addrlist;
- result->h_addrtype = af;
- result->h_length = len;
-
- *h_errnop = NETDB_SUCCESS;
- DEBUGP("returning\n");
- return(NSS_STATUS_SUCCESS);
-}
-
-/*
- * Local Variables:
- * compile-command: "gcc -shared -Wall -g -o libnss_icmp.so.2 nss-icmp.c"
- * End:
- */
Dolda2000 GitWeb / icmp-dn.git / blobdiff