/* $NetBSD: dns_nw.c,v 1.1.1.2 2012/09/09 16:07:52 christos Exp $ */ /* * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC") * Copyright (c) 1996-1999 by Internet Software Consortium. * * Permission to use, copy, modify, and distribute this software for any * purpose with or without fee is hereby granted, provided that the above * copyright notice and this permission notice appear in all copies. * * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR * ANY SPECIAL, DIRECT, 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. */ #if defined(LIBC_SCCS) && !defined(lint) static const char rcsid[] = "Id: dns_nw.c,v 1.12 2005/04/27 04:56:22 sra Exp "; #endif /* LIBC_SCCS and not lint */ /* Imports. */ #include "port_before.h" #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "port_after.h" #include "irs_p.h" #include "dns_p.h" #ifdef SPRINTF_CHAR # define SPRINTF(x) strlen(sprintf/**/x) #else # define SPRINTF(x) sprintf x #endif /* Definitions. */ #define MAXALIASES 35 #define MAXPACKET (64*1024) struct pvt { struct nwent net; char * ali[MAXALIASES]; char buf[BUFSIZ+1]; struct __res_state * res; void (*free_res)(void *); }; typedef union { long al; char ac; } align; enum by_what { by_addr, by_name }; /* Forwards. */ static void nw_close(struct irs_nw *); static struct nwent * nw_byname(struct irs_nw *, const char *, int); static struct nwent * nw_byaddr(struct irs_nw *, void *, int, int); static struct nwent * nw_next(struct irs_nw *); static void nw_rewind(struct irs_nw *); static void nw_minimize(struct irs_nw *); static struct __res_state * nw_res_get(struct irs_nw *this); static void nw_res_set(struct irs_nw *this, struct __res_state *res, void (*free_res)(void *)); static struct nwent * get1101byaddr(struct irs_nw *, u_char *, int); static struct nwent * get1101byname(struct irs_nw *, const char *); static struct nwent * get1101answer(struct irs_nw *, u_char *ansbuf, int anslen, enum by_what by_what, int af, const char *name, const u_char *addr, int addrlen); static struct nwent * get1101mask(struct irs_nw *this, struct nwent *); static int make1101inaddr(const u_char *, int, char *, int); static void normalize_name(char *name); static int init(struct irs_nw *this); /* Exports. */ struct irs_nw * irs_dns_nw(struct irs_acc *this) { struct irs_nw *nw; struct pvt *pvt; UNUSED(this); if (!(pvt = memget(sizeof *pvt))) { errno = ENOMEM; return (NULL); } memset(pvt, 0, sizeof *pvt); if (!(nw = memget(sizeof *nw))) { memput(pvt, sizeof *pvt); errno = ENOMEM; return (NULL); } memset(nw, 0x5e, sizeof *nw); nw->private = pvt; nw->close = nw_close; nw->byname = nw_byname; nw->byaddr = nw_byaddr; nw->next = nw_next; nw->rewind = nw_rewind; nw->minimize = nw_minimize; nw->res_get = nw_res_get; nw->res_set = nw_res_set; return (nw); } /* Methods. */ static void nw_close(struct irs_nw *this) { struct pvt *pvt = (struct pvt *)this->private; nw_minimize(this); if (pvt->res && pvt->free_res) (*pvt->free_res)(pvt->res); memput(pvt, sizeof *pvt); memput(this, sizeof *this); } static struct nwent * nw_byname(struct irs_nw *this, const char *name, int af) { struct pvt *pvt = (struct pvt *)this->private; if (init(this) == -1) return (NULL); switch (af) { case AF_INET: return (get1101byname(this, name)); default: (void)NULL; } RES_SET_H_ERRNO(pvt->res, NETDB_INTERNAL); errno = EAFNOSUPPORT; return (NULL); } static struct nwent * nw_byaddr(struct irs_nw *this, void *net, int len, int af) { struct pvt *pvt = (struct pvt *)this->private; if (init(this) == -1) return (NULL); switch (af) { case AF_INET: return (get1101byaddr(this, net, len)); default: (void)NULL; } RES_SET_H_ERRNO(pvt->res, NETDB_INTERNAL); errno = EAFNOSUPPORT; return (NULL); } static struct nwent * nw_next(struct irs_nw *this) { UNUSED(this); return (NULL); } static void nw_rewind(struct irs_nw *this) { UNUSED(this); /* NOOP */ } static void nw_minimize(struct irs_nw *this) { struct pvt *pvt = (struct pvt *)this->private; if (pvt->res) res_nclose(pvt->res); } static struct __res_state * nw_res_get(struct irs_nw *this) { struct pvt *pvt = (struct pvt *)this->private; if (!pvt->res) { struct __res_state *res; res = (struct __res_state *)malloc(sizeof *res); if (!res) { errno = ENOMEM; return (NULL); } memset(res, 0, sizeof *res); nw_res_set(this, res, free); } return (pvt->res); } static void nw_res_set(struct irs_nw *this, struct __res_state *res, void (*free_res)(void *)) { struct pvt *pvt = (struct pvt *)this->private; if (pvt->res && pvt->free_res) { res_nclose(pvt->res); (*pvt->free_res)(pvt->res); } pvt->res = res; pvt->free_res = free_res; } /* Private. */ static struct nwent * get1101byname(struct irs_nw *this, const char *name) { struct pvt *pvt = (struct pvt *)this->private; u_char *ansbuf; int anslen; struct nwent *result; ansbuf = memget(MAXPACKET); if (ansbuf == NULL) { errno = ENOMEM; RES_SET_H_ERRNO(pvt->res, NETDB_INTERNAL); return (NULL); } anslen = res_nsearch(pvt->res, name, C_IN, T_PTR, ansbuf, MAXPACKET); if (anslen < 0) { memput(ansbuf, MAXPACKET); return (NULL); } result = get1101mask(this, get1101answer(this, ansbuf, anslen, by_name, AF_INET, name, NULL, 0)); memput(ansbuf, MAXPACKET); return (result); } static struct nwent * get1101byaddr(struct irs_nw *this, u_char *net, int len) { struct pvt *pvt = (struct pvt *)this->private; char qbuf[sizeof "255.255.255.255.in-addr.arpa"]; struct nwent *result; u_char *ansbuf; int anslen; if (len < 1 || len > 32) { errno = EINVAL; RES_SET_H_ERRNO(pvt->res, NETDB_INTERNAL); return (NULL); } if (make1101inaddr(net, len, qbuf, sizeof qbuf) < 0) return (NULL); ansbuf = memget(MAXPACKET); if (ansbuf == NULL) { errno = ENOMEM; RES_SET_H_ERRNO(pvt->res, NETDB_INTERNAL); return (NULL); } anslen = res_nquery(pvt->res, qbuf, C_IN, T_PTR, ansbuf, MAXPACKET); if (anslen < 0) { memput(ansbuf, MAXPACKET); return (NULL); } result = get1101mask(this, get1101answer(this, ansbuf, anslen, by_addr, AF_INET, NULL, net, len)); memput(ansbuf, MAXPACKET); return (result); } static struct nwent * get1101answer(struct irs_nw *this, u_char *ansbuf, int anslen, enum by_what by_what, int af, const char *name, const u_char *addr, int addrlen) { struct pvt *pvt = (struct pvt *)this->private; int type, class, ancount, qdcount, haveanswer; char *bp, *ep, **ap; u_char *cp, *eom; HEADER *hp; /* Initialize, and parse header. */ eom = ansbuf + anslen; if (ansbuf + HFIXEDSZ > eom) { RES_SET_H_ERRNO(pvt->res, NO_RECOVERY); return (NULL); } hp = (HEADER *)ansbuf; cp = ansbuf + HFIXEDSZ; qdcount = ntohs(hp->qdcount); while (qdcount-- > 0) { int n = dn_skipname(cp, eom); cp += n + QFIXEDSZ; if (n < 0 || cp > eom) { RES_SET_H_ERRNO(pvt->res, NO_RECOVERY); return (NULL); } } ancount = ntohs(hp->ancount); if (!ancount) { if (hp->aa) RES_SET_H_ERRNO(pvt->res, HOST_NOT_FOUND); else RES_SET_H_ERRNO(pvt->res, TRY_AGAIN); return (NULL); } /* Prepare a return structure. */ bp = pvt->buf; ep = pvt->buf + sizeof(pvt->buf); pvt->net.n_name = NULL; pvt->net.n_aliases = pvt->ali; pvt->net.n_addrtype = af; pvt->net.n_addr = NULL; pvt->net.n_length = addrlen; /* Save input key if given. */ switch (by_what) { case by_name: if (name != NULL) { int n = strlen(name) + 1; if (n > (ep - bp)) { RES_SET_H_ERRNO(pvt->res, NO_RECOVERY); return (NULL); } pvt->net.n_name = strcpy(bp, name); /* (checked) */ bp += n; } break; case by_addr: if (addr != NULL && addrlen != 0) { int n = addrlen / 8 + ((addrlen % 8) != 0); if (INADDRSZ > (ep - bp)) { RES_SET_H_ERRNO(pvt->res, NO_RECOVERY); return (NULL); } memset(bp, 0, INADDRSZ); memcpy(bp, addr, n); pvt->net.n_addr = bp; bp += INADDRSZ; } break; default: abort(); } /* Parse the answer, collect aliases. */ ap = pvt->ali; haveanswer = 0; while (--ancount >= 0 && cp < eom) { int n = dn_expand(ansbuf, eom, cp, bp, ep - bp); cp += n; /*%< Owner */ if (n < 0 || !maybe_dnok(pvt->res, bp) || cp + 3 * INT16SZ + INT32SZ > eom) { RES_SET_H_ERRNO(pvt->res, NO_RECOVERY); return (NULL); } GETSHORT(type, cp); /*%< Type */ GETSHORT(class, cp); /*%< Class */ cp += INT32SZ; /*%< TTL */ GETSHORT(n, cp); /*%< RDLENGTH */ if (class == C_IN && type == T_PTR) { int nn; nn = dn_expand(ansbuf, eom, cp, bp, ep - bp); if (nn < 0 || !maybe_hnok(pvt->res, bp) || nn != n) { RES_SET_H_ERRNO(pvt->res, NO_RECOVERY); return (NULL); } normalize_name(bp); switch (by_what) { case by_addr: { if (pvt->net.n_name == NULL) pvt->net.n_name = bp; else if (ns_samename(pvt->net.n_name, bp) == 1) break; else *ap++ = bp; nn = strlen(bp) + 1; bp += nn; haveanswer++; break; } case by_name: { u_int b1, b2, b3, b4; if (pvt->net.n_addr != NULL || sscanf(bp, "%u.%u.%u.%u.in-addr.arpa", &b1, &b2, &b3, &b4) != 4) break; if ((ep - bp) < INADDRSZ) { RES_SET_H_ERRNO(pvt->res, NO_RECOVERY); return (NULL); } pvt->net.n_addr = bp; *bp++ = b4; *bp++ = b3; *bp++ = b2; *bp++ = b1; pvt->net.n_length = INADDRSZ * 8; haveanswer++; } } } cp += n; /*%< RDATA */ } if (!haveanswer) { RES_SET_H_ERRNO(pvt->res, TRY_AGAIN); return (NULL); } *ap = NULL; return (&pvt->net); } static struct nwent * get1101mask(struct irs_nw *this, struct nwent *nwent) { struct pvt *pvt = (struct pvt *)this->private; char qbuf[sizeof "255.255.255.255.in-addr.arpa"], owner[MAXDNAME]; int anslen, type, class, ancount, qdcount; u_char *ansbuf, *cp, *eom; HEADER *hp; if (!nwent) return (NULL); if (make1101inaddr(nwent->n_addr, nwent->n_length, qbuf, sizeof qbuf) < 0) { /* "First, do no harm." */ return (nwent); } ansbuf = memget(MAXPACKET); if (ansbuf == NULL) { errno = ENOMEM; RES_SET_H_ERRNO(pvt->res, NETDB_INTERNAL); return (NULL); } /* Query for the A RR that would hold this network's mask. */ anslen = res_nquery(pvt->res, qbuf, C_IN, T_A, ansbuf, MAXPACKET); if (anslen < HFIXEDSZ) { memput(ansbuf, MAXPACKET); return (nwent); } /* Initialize, and parse header. */ hp = (HEADER *)ansbuf; cp = ansbuf + HFIXEDSZ; eom = ansbuf + anslen; qdcount = ntohs(hp->qdcount); while (qdcount-- > 0) { int n = dn_skipname(cp, eom); cp += n + QFIXEDSZ; if (n < 0 || cp > eom) { memput(ansbuf, MAXPACKET); return (nwent); } } ancount = ntohs(hp->ancount); /* Parse the answer, collect aliases. */ while (--ancount >= 0 && cp < eom) { int n = dn_expand(ansbuf, eom, cp, owner, sizeof owner); if (n < 0 || !maybe_dnok(pvt->res, owner)) break; cp += n; /*%< Owner */ if (cp + 3 * INT16SZ + INT32SZ > eom) break; GETSHORT(type, cp); /*%< Type */ GETSHORT(class, cp); /*%< Class */ cp += INT32SZ; /*%< TTL */ GETSHORT(n, cp); /*%< RDLENGTH */ if (cp + n > eom) break; if (n == INADDRSZ && class == C_IN && type == T_A && ns_samename(qbuf, owner) == 1) { /* This A RR indicates the actual netmask. */ int nn, mm; nwent->n_length = 0; for (nn = 0; nn < INADDRSZ; nn++) for (mm = 7; mm >= 0; mm--) if (cp[nn] & (1 << mm)) nwent->n_length++; else break; } cp += n; /*%< RDATA */ } memput(ansbuf, MAXPACKET); return (nwent); } static int make1101inaddr(const u_char *net, int bits, char *name, int size) { int n, m; char *ep; ep = name + size; /* Zero fill any whole bytes left out of the prefix. */ for (n = (32 - bits) / 8; n > 0; n--) { if (ep - name < (int)(sizeof "0.")) goto emsgsize; m = SPRINTF((name, "0.")); name += m; } /* Format the partial byte, if any, within the prefix. */ if ((n = bits % 8) != 0) { if (ep - name < (int)(sizeof "255.")) goto emsgsize; m = SPRINTF((name, "%u.", net[bits / 8] & ~((1 << (8 - n)) - 1))); name += m; } /* Format the whole bytes within the prefix. */ for (n = bits / 8; n > 0; n--) { if (ep - name < (int)(sizeof "255.")) goto emsgsize; m = SPRINTF((name, "%u.", net[n - 1])); name += m; } /* Add the static text. */ if (ep - name < (int)(sizeof "in-addr.arpa")) goto emsgsize; (void) SPRINTF((name, "in-addr.arpa")); return (0); emsgsize: errno = EMSGSIZE; return (-1); } static void normalize_name(char *name) { char *t; /* Make lower case. */ for (t = name; *t; t++) if (isascii((unsigned char)*t) && isupper((unsigned char)*t)) *t = tolower((*t)&0xff); /* Remove trailing dots. */ while (t > name && t[-1] == '.') *--t = '\0'; } static int init(struct irs_nw *this) { struct pvt *pvt = (struct pvt *)this->private; if (!pvt->res && !nw_res_get(this)) return (-1); if (((pvt->res->options & RES_INIT) == 0U) && res_ninit(pvt->res) == -1) return (-1); return (0); } /*! \file */