[icmp-dn.git] / nss-icmp.c

#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>

#define CONFIGFILE "/etc/nss-icmp.conf"

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;
    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);
    }
    
    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) {
	ap = (u_int8_t *)addr;
	if(inet_ntop(af, addr, addrbuf, sizeof(addrbuf)) == NULL) {
	    *errnop = errno;
	    *h_errnop = NETDB_INTERNAL;
	    return(NSS_STATUS_UNAVAIL);
	}
    
	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]);
	
	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 {
	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]);
	    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[an] = p3;
	    p3 += thislen + 1;
	    if(++an == 16) {
		*errnop = ENOMEM;
		*h_errnop = NETDB_INTERNAL;
		return(NSS_STATUS_UNAVAIL);
	    }
	}
    }
    
    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;
    return(NSS_STATUS_SUCCESS);
}
Commit	Line	Data
2dec74ab DC	1	#include <stdlib.h>
	2	#include <stdio.h>
	3	#include <unistd.h>
	4	#include <string.h>
	5	#include <errno.h>
f0df8f66	6	#include <time.h>
2dec74ab DC	7	#include <sys/socket.h>
	8	#include <netinet/in.h>
	9	#include <netdb.h>
	10	#include <arpa/inet.h>
	11	#include <nss.h>
	12	#include <sys/types.h>
	13	#include <fcntl.h>
	14
15a913c2 DC	15	#define CONFIGFILE "/etc/nss-icmp.conf"
	16
	17	struct cache {
	18	struct cache next, prev;
	19	char *addr;
	20	socklen_t addrlen;
	21	int af;
	22	int notfound;
	23	char **names;
f0df8f66	24	time_t at, ttl;
15a913c2 DC	25	};
	26
	27	static int inited = 0;
	28	static int timeout = -1;
	29	static int usecache = 1;
f0df8f66	30	static time_t nfttl = 300;
15a913c2 DC	31	static struct cache *cache = NULL;
	32
	33	static void readconfig(void)
	34	{
	35	FILE *f;
	36	char linebuf[1024];
	37	char p, p2;
	38
	39	if((f = fopen(CONFIGFILE, "r")) == NULL)
	40	return;
	41
	42	while(fgets(linebuf, sizeof(linebuf), f) != NULL) {
	43	if(linebuf[0] == '#')
	44	continue;
	45	if((p = strchr(linebuf, '\n')) != NULL)
	46	*p = 0;
	47	if((p = strchr(linebuf, ' ')) != NULL) {
	48	p2 = p + 1;
	49	*p = 0;
	50	}
	51	if(!strcmp(linebuf, "timeout")) {
	52	if(p2 == NULL)
	53	continue;
	54	timeout = atoi(p2);
	55	}
f0df8f66 DC	56	if(!strcmp(linebuf, "ttlnotfound")) {
	57	if(p2 == NULL)
	58	continue;
	59	nfttl = atoi(p2);
	60	}
15a913c2 DC	61	if(!strcmp(linebuf, "nocache")) {
	62	usecache = 0;
	63	}
	64	}
	65
	66	fclose(f);
	67	}
	68
	69	static void freecache(struct cache *cc)
	70	{
	71	int i;
	72
	73	if(cc->next != NULL)
	74	cc->next->prev = cc->prev;
	75	if(cc->prev != NULL)
	76	cc->prev->next = cc->next;
	77	if(cc == cache)
	78	cache = cc->next;
	79	if(cc->addr != NULL)
	80	free(cc->addr);
	81	if(cc->names != NULL) {
	82	for(i = 0; cc->names[i] != NULL; i++)
	83	free(cc->names[i]);
	84	free(cc->names);
	85	}
	86	free(cc);
	87	}
	88
f0df8f66	89	static void cachenotfound(const void *addr, socklen_t len, int af, time_t ttl)
15a913c2 DC	90	{
	91	struct cache *cc;
	92
	93	for(cc = cache; cc != NULL; cc = cc->next) {
	94	if((cc->af == af) && (cc->addrlen == len) && !memcmp(cc->addr, addr, len))
	95	break;
	96	}
	97	if(cc == NULL) {
	98	if((cc = malloc(sizeof(*cc))) == NULL)
	99	return;
	100	memset(cc, 0, sizeof(*cc));
	101	if((cc->addr = malloc(len)) == NULL) {
	102	freecache(cc);
	103	return;
	104	}
	105	memcpy(cc->addr, addr, len);
	106	cc->addrlen = len;
	107	cc->af = af;
f0df8f66 DC	108	cc->at = time(NULL);
f0df8f66 DC	109	cc->ttl = ttl;
15a913c2 DC	110
	111	cc->notfound = 1;
	112
	113	cc->next = cache;
	114	if(cache != NULL)
	115	cache->prev = cc;
	116	cache = cc;
	117	}
	118	}
	119
f0df8f66	120	static void updatecache(const void addr, socklen_t len, int af, char *names, time_t ttl)
15a913c2 DC	121	{
	122	int i;
	123	struct cache *cc;
	124
	125	for(cc = cache; cc != NULL; cc = cc->next) {
f0df8f66	126	if((cc->af == af) && (cc->addrlen == len) && !memcmp(cc->addr, addr, len))
15a913c2 DC	127	break;
	128	}
	129	if(cc == NULL) {
	130	if((cc = malloc(sizeof(*cc))) == NULL)
	131	return;
	132	memset(cc, 0, sizeof(*cc));
f0df8f66	133	if((cc->addr = malloc(len)) == NULL) {
15a913c2 DC	134	freecache(cc);
	135	return;
	136	}
f0df8f66 DC	137	memcpy(cc->addr, addr, len);
	138	cc->addrlen = len;
	139	cc->af = af;
	140	cc->at = time(NULL);
	141	cc->ttl = ttl;
15a913c2	142
f0df8f66	143	for(i = 0; names[i] != NULL; i++);
15a913c2 DC	144	if((cc->names = malloc(sizeof((cc->names)) (i + 1))) == NULL) {
	145	freecache(cc);
	146	return;
	147	}
	148	memset(cc->names, 0, sizeof((cc->names)) (i + 1));
f0df8f66 DC	149	for(i = 0; names[i] != NULL; i++) {
f0df8f66 DC	150	if((cc->names[i] = malloc(strlen(names[i]) + 1)) == NULL) {
15a913c2 DC	151	freecache(cc);
	152	return;
	153	}
f0df8f66	154	strcpy(cc->names[i], names[i]);
15a913c2 DC	155	}
	156
	157	cc->next = cache;
	158	if(cache != NULL)
	159	cache->prev = cc;
	160	cache = cc;
	161	}
	162	}
	163
f0df8f66 DC	164	static void expirecache(void)
	165	{
	166	struct cache cc, next;
	167	time_t now;
	168
	169	now = time(NULL);
	170	for(cc = cache; cc != NULL; cc = next) {
	171	next = cc->next;
	172	if(now - cc->at > cc->ttl) {
	173	freecache(cc);
	174	continue;
	175	}
	176	}
	177	}
	178
2dec74ab DC	179	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)
2dec74ab DC	180	{
15a913c2	181	int i, ret;
2dec74ab DC	182	struct retstruct {
	183	char *aliaslist[16];
	184	char *addrlist[2];
	185	char retaddr[16];
	186	} *retbuf;
	187	char addrbuf[1024];
f0df8f66	188	int an, thislen, ttl;
2dec74ab DC	189	char p, p2, *p3;
	190	u_int8_t *ap;
	191	pid_t child;
	192	int pfd[2];
	193	int rl;
15a913c2 DC	194	struct cache *cc;
	195
	196	if(!inited) {
	197	readconfig();
	198	inited = 1;
	199	}
2dec74ab DC	200
	201	retbuf = (struct retstruct *)buffer;
	202	if((buflen < sizeof(*retbuf)) \|\| (len > sizeof(retbuf->retaddr))) {
	203	*errnop = ENOMEM;
	204	*h_errnop = NETDB_INTERNAL;
	205	return(NSS_STATUS_UNAVAIL);
	206	}
	207
f416a8cd	208	if(usecache) {
f0df8f66	209	expirecache();
f416a8cd DC	210	for(cc = cache; cc != NULL; cc = cc->next) {
	211	if((cc->af == af) && (cc->addrlen == len) && !memcmp(cc->addr, addr, len))
	212	break;
	213	}
	214	} else {
	215	cc = NULL;
2dec74ab DC	216	}
2dec74ab DC	217
15a913c2 DC	218	if(cc == NULL) {
	219	ap = (u_int8_t *)addr;
	220	if(inet_ntop(af, addr, addrbuf, sizeof(addrbuf)) == NULL) {
2dec74ab DC	221	*errnop = errno;
2dec74ab DC	222	*h_errnop = NETDB_INTERNAL;
2dec74ab DC	223	return(NSS_STATUS_UNAVAIL);
2dec74ab DC	224	}
15a913c2 DC	225
	226	if(pipe(pfd)) {
	227	*errnop = errno;
2dec74ab	228	*h_errnop = NETDB_INTERNAL;
2dec74ab DC	229	return(NSS_STATUS_UNAVAIL);
2dec74ab DC	230	}
15a913c2 DC	231	/* I honestly don't know if it is considered OK to fork in other
	232	* people's programs. We need a SUID worker, though, so there's
	233	* little choice that I can see. */
	234	if((child = fork()) < 0) {
	235	*errnop = errno;
2dec74ab DC	236	*h_errnop = NETDB_INTERNAL;
	237	return(NSS_STATUS_UNAVAIL);
	238	}
15a913c2 DC	239
	240	if(child == 0) {
	241	int i, fd;
	242	char timeoutbuf[128];
	243
	244	if((fd = open("/dev/null", O_WRONLY)) < 0)
	245	exit(127);
	246	close(pfd[0]);
	247	dup2(pfd[1], 1);
	248	dup2(fd, 2);
	249	for(i = 3; i < FD_SETSIZE; i++)
	250	close(i);
	251
	252	if(timeout != -1) {
	253	snprintf(timeoutbuf, sizeof(timeoutbuf), "%i", timeout);
f0df8f66	254	execlp("idnlookup", "idnlookup", "-Tt", timeoutbuf, addrbuf, NULL);
15a913c2	255	} else {
f0df8f66	256	execlp("idnlookup", "idnlookup", "-T", addrbuf, NULL);
15a913c2 DC	257	}
	258	exit(127);
	259	}
	260
	261	close(pfd[1]);
	262
	263	rl = 0;
	264	do {
	265	ret = read(pfd[0], addrbuf + rl, sizeof(addrbuf) - rl);
	266	if(ret < 0) {
	267	*errnop = errno;
	268	*h_errnop = NETDB_INTERNAL;
	269	close(pfd[0]);
	270	return(NSS_STATUS_UNAVAIL);
	271	}
	272	rl += ret;
	273	if(rl >= sizeof(addrbuf) - 1) {
	274	*errnop = ENOMEM;
	275	*h_errnop = NETDB_INTERNAL;
	276	close(pfd[0]);
	277	return(NSS_STATUS_UNAVAIL);
	278	}
	279	} while(ret != 0);
	280	addrbuf[rl] = 0;
	281	close(pfd[0]);
f0df8f66 DC	282
	283	if((p = strchr(addrbuf, '\n')) == NULL) {
	284	if(usecache)
	285	cachenotfound(addr, len, af, nfttl);
	286	h_errnop = TRY_AGAIN; / XXX: Is this correct? */
	287	return(NSS_STATUS_NOTFOUND);
	288	}
	289	*(p++) = 0;
	290	ttl = atoi(addrbuf);
	291
15a913c2	292	an = 0;
15a913c2 DC	293	p3 = buffer + sizeof(*retbuf);
	294	while((p2 = strchr(p, '\n')) != NULL) {
	295	*p2 = 0;
	296	thislen = p2 - p;
	297	if(thislen == 0)
	298	continue;
	299	if((p3 - buffer) + thislen + 1 > buflen) {
	300	*errnop = ENOMEM;
	301	*h_errnop = NETDB_INTERNAL;
	302	return(NSS_STATUS_UNAVAIL);
	303	}
	304	memcpy(p3, p, thislen + 1);
	305	retbuf->aliaslist[an] = p3;
	306	p3 += thislen + 1;
	307	p = p2 + 1;
	308	if(++an == 16) {
	309	*errnop = ENOMEM;
	310	*h_errnop = NETDB_INTERNAL;
	311	return(NSS_STATUS_UNAVAIL);
	312	}
	313	}
	314	if(an == 0) {
f416a8cd	315	if(usecache)
f0df8f66	316	cachenotfound(addr, len, af, nfttl);
15a913c2 DC	317	h_errnop = TRY_AGAIN; / XXX: Is this correct? */
	318	return(NSS_STATUS_NOTFOUND);
	319	}
	320	retbuf->aliaslist[an] = NULL;
f0df8f66 DC	321
	322	if(usecache)
	323	updatecache(addr, len, af, retbuf->aliaslist, ttl);
15a913c2 DC	324	} else {
	325	if(cc->notfound) {
	326	h_errnop = TRY_AGAIN; / XXX: Is this correct? */
	327	return(NSS_STATUS_NOTFOUND);
	328	}
	329
	330	p3 = buffer + sizeof(*retbuf);
	331	for(i = 0; cc->names[i] != NULL; i++) {
	332	thislen = strlen(cc->names[i]);
	333	if((p3 - buffer) + thislen + 1 > buflen) {
	334	*errnop = ENOMEM;
	335	*h_errnop = NETDB_INTERNAL;
	336	return(NSS_STATUS_UNAVAIL);
	337	}
	338	memcpy(p3, cc->names[i], thislen + 1);
	339	retbuf->aliaslist[an] = p3;
	340	p3 += thislen + 1;
	341	if(++an == 16) {
	342	*errnop = ENOMEM;
	343	*h_errnop = NETDB_INTERNAL;
	344	return(NSS_STATUS_UNAVAIL);
	345	}
2dec74ab DC	346	}
2dec74ab DC	347	}
2dec74ab DC	348
	349	memcpy(retbuf->retaddr, addr, len);
	350	retbuf->addrlist[0] = retbuf->retaddr;
	351	retbuf->addrlist[1] = NULL;
	352	result->h_name = retbuf->aliaslist[0];
	353	result->h_aliases = retbuf->aliaslist;
	354	result->h_addr_list = retbuf->addrlist;
	355	result->h_addrtype = af;
	356	result->h_length = len;
	357
	358	*h_errnop = NETDB_SUCCESS;
	359	return(NSS_STATUS_SUCCESS);
	360	}