diff options
Diffstat (limited to 'freebsd-userspace/lib/libc/resolv/res_findzonecut.c')
| -rw-r--r-- | freebsd-userspace/lib/libc/resolv/res_findzonecut.c | 727 |
1 files changed, 727 insertions, 0 deletions
diff --git a/freebsd-userspace/lib/libc/resolv/res_findzonecut.c b/freebsd-userspace/lib/libc/resolv/res_findzonecut.c new file mode 100644 index 00000000..23c1af4f --- /dev/null +++ b/freebsd-userspace/lib/libc/resolv/res_findzonecut.c @@ -0,0 +1,727 @@ +#if !defined(lint) && !defined(SABER) +static const char rcsid[] = "$Id: res_findzonecut.c,v 1.7.18.3 2005/10/11 00:25:11 marka Exp $"; +#endif /* not lint */ + +/* + * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC") + * Copyright (c) 1999 by Internet Software Consortium. + * + * Permission to use, copy, modify, and distribute this software for any + * purpose with or without fee is hereby granted, provided that the above + * copyright notice and this permission notice appear in all copies. + * + * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES + * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF + * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR + * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES + * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN + * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT + * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. + */ + +#include <sys/cdefs.h> +__FBSDID("$FreeBSD$"); + +/* Import. */ + +#include "port_before.h" + +#include <sys/param.h> +#include <sys/socket.h> +#include <sys/time.h> + +#include <netinet/in.h> +#include <arpa/inet.h> +#include <arpa/nameser.h> + +#include <errno.h> +#include <limits.h> +#include <netdb.h> +#include <stdarg.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> + +#include <isc/list.h> + +#include "port_after.h" + +#include <resolv.h> + +/* Data structures. */ + +typedef struct rr_a { + LINK(struct rr_a) link; + union res_sockaddr_union addr; +} rr_a; +typedef LIST(rr_a) rrset_a; + +typedef struct rr_ns { + LINK(struct rr_ns) link; + const char * name; + unsigned int flags; + rrset_a addrs; +} rr_ns; +typedef LIST(rr_ns) rrset_ns; + +#define RR_NS_HAVE_V4 0x01 +#define RR_NS_HAVE_V6 0x02 + +/* Forward. */ + +static int satisfy(res_state, const char *, rrset_ns *, + union res_sockaddr_union *, int); +static int add_addrs(res_state, rr_ns *, + union res_sockaddr_union *, int); +static int get_soa(res_state, const char *, ns_class, int, + char *, size_t, char *, size_t, + rrset_ns *); +static int get_ns(res_state, const char *, ns_class, int, rrset_ns *); +static int get_glue(res_state, ns_class, int, rrset_ns *); +static int save_ns(res_state, ns_msg *, ns_sect, + const char *, ns_class, int, rrset_ns *); +static int save_a(res_state, ns_msg *, ns_sect, + const char *, ns_class, int, rr_ns *); +static void free_nsrrset(rrset_ns *); +static void free_nsrr(rrset_ns *, rr_ns *); +static rr_ns * find_ns(rrset_ns *, const char *); +static int do_query(res_state, const char *, ns_class, ns_type, + u_char *, ns_msg *); +static void res_dprintf(const char *, ...) ISC_FORMAT_PRINTF(1, 2); + +/* Macros. */ + +#define DPRINTF(x) do {\ + int save_errno = errno; \ + if ((statp->options & RES_DEBUG) != 0U) res_dprintf x; \ + errno = save_errno; \ + } while (0) + +/* Public. */ + +/*% + * find enclosing zone for a <dname,class>, and some server addresses + * + * parameters: + *\li res - resolver context to work within (is modified) + *\li dname - domain name whose enclosing zone is desired + *\li class - class of dname (and its enclosing zone) + *\li zname - found zone name + *\li zsize - allocated size of zname + *\li addrs - found server addresses + *\li naddrs - max number of addrs + * + * return values: + *\li < 0 - an error occurred (check errno) + *\li = 0 - zname is now valid, but addrs[] wasn't changed + *\li > 0 - zname is now valid, and return value is number of addrs[] found + * + * notes: + *\li this function calls res_nsend() which means it depends on correctly + * functioning recursive nameservers (usually defined in /etc/resolv.conf + * or its local equivilent). + * + *\li we start by asking for an SOA<dname,class>. if we get one as an + * answer, that just means <dname,class> is a zone top, which is fine. + * more than likely we'll be told to go pound sand, in the form of a + * negative answer. + * + *\li note that we are not prepared to deal with referrals since that would + * only come from authority servers and our correctly functioning local + * recursive server would have followed the referral and got us something + * more definite. + * + *\li if the authority section contains an SOA, this SOA should also be the + * closest enclosing zone, since any intermediary zone cuts would've been + * returned as referrals and dealt with by our correctly functioning local + * recursive name server. but an SOA in the authority section should NOT + * match our dname (since that would have been returned in the answer + * section). an authority section SOA has to be "above" our dname. + * + *\li however, since authority section SOA's were once optional, it's + * possible that we'll have to go hunting for the enclosing SOA by + * ripping labels off the front of our dname -- this is known as "doing + * it the hard way." + * + *\li ultimately we want some server addresses, which are ideally the ones + * pertaining to the SOA.MNAME, but only if there is a matching NS RR. + * so the second phase (after we find an SOA) is to go looking for the + * NS RRset for that SOA's zone. + * + *\li no answer section processed by this code is allowed to contain CNAME + * or DNAME RR's. for the SOA query this means we strip a label and + * keep going. for the NS and A queries this means we just give up. + */ + +#ifndef _LIBC +int +res_findzonecut(res_state statp, const char *dname, ns_class class, int opts, + char *zname, size_t zsize, struct in_addr *addrs, int naddrs) +{ + int result, i; + union res_sockaddr_union *u; + + + opts |= RES_IPV4ONLY; + opts &= ~RES_IPV6ONLY; + + u = calloc(naddrs, sizeof(*u)); + if (u == NULL) + return(-1); + + result = res_findzonecut2(statp, dname, class, opts, zname, zsize, + u, naddrs); + + for (i = 0; i < result; i++) { + addrs[i] = u[i].sin.sin_addr; + } + free(u); + return (result); +} +#endif + +int +res_findzonecut2(res_state statp, const char *dname, ns_class class, int opts, + char *zname, size_t zsize, union res_sockaddr_union *addrs, + int naddrs) +{ + char mname[NS_MAXDNAME]; + u_long save_pfcode; + rrset_ns nsrrs; + int n; + + DPRINTF(("START dname='%s' class=%s, zsize=%ld, naddrs=%d", + dname, p_class(class), (long)zsize, naddrs)); + save_pfcode = statp->pfcode; + statp->pfcode |= RES_PRF_HEAD2 | RES_PRF_HEAD1 | RES_PRF_HEADX | + RES_PRF_QUES | RES_PRF_ANS | + RES_PRF_AUTH | RES_PRF_ADD; + INIT_LIST(nsrrs); + + DPRINTF(("get the soa, and see if it has enough glue")); + if ((n = get_soa(statp, dname, class, opts, zname, zsize, + mname, sizeof mname, &nsrrs)) < 0 || + ((opts & RES_EXHAUSTIVE) == 0 && + (n = satisfy(statp, mname, &nsrrs, addrs, naddrs)) > 0)) + goto done; + + DPRINTF(("get the ns rrset and see if it has enough glue")); + if ((n = get_ns(statp, zname, class, opts, &nsrrs)) < 0 || + ((opts & RES_EXHAUSTIVE) == 0 && + (n = satisfy(statp, mname, &nsrrs, addrs, naddrs)) > 0)) + goto done; + + DPRINTF(("get the missing glue and see if it's finally enough")); + if ((n = get_glue(statp, class, opts, &nsrrs)) >= 0) + n = satisfy(statp, mname, &nsrrs, addrs, naddrs); + + done: + DPRINTF(("FINISH n=%d (%s)", n, (n < 0) ? strerror(errno) : "OK")); + free_nsrrset(&nsrrs); + statp->pfcode = save_pfcode; + return (n); +} + +/* Private. */ + +static int +satisfy(res_state statp, const char *mname, rrset_ns *nsrrsp, + union res_sockaddr_union *addrs, int naddrs) +{ + rr_ns *nsrr; + int n, x; + + n = 0; + nsrr = find_ns(nsrrsp, mname); + if (nsrr != NULL) { + x = add_addrs(statp, nsrr, addrs, naddrs); + addrs += x; + naddrs -= x; + n += x; + } + for (nsrr = HEAD(*nsrrsp); + nsrr != NULL && naddrs > 0; + nsrr = NEXT(nsrr, link)) + if (ns_samename(nsrr->name, mname) != 1) { + x = add_addrs(statp, nsrr, addrs, naddrs); + addrs += x; + naddrs -= x; + n += x; + } + DPRINTF(("satisfy(%s): %d", mname, n)); + return (n); +} + +static int +add_addrs(res_state statp, rr_ns *nsrr, + union res_sockaddr_union *addrs, int naddrs) +{ + rr_a *arr; + int n = 0; + + for (arr = HEAD(nsrr->addrs); arr != NULL; arr = NEXT(arr, link)) { + if (naddrs <= 0) + return (0); + *addrs++ = arr->addr; + naddrs--; + n++; + } + DPRINTF(("add_addrs: %d", n)); + return (n); +} + +static int +get_soa(res_state statp, const char *dname, ns_class class, int opts, + char *zname, size_t zsize, char *mname, size_t msize, + rrset_ns *nsrrsp) +{ + char tname[NS_MAXDNAME]; + u_char *resp = NULL; + int n, i, ancount, nscount; + ns_sect sect; + ns_msg msg; + u_int rcode; + + /* + * Find closest enclosing SOA, even if it's for the root zone. + */ + + /* First canonicalize dname (exactly one unescaped trailing "."). */ + if (ns_makecanon(dname, tname, sizeof tname) < 0) + goto cleanup; + dname = tname; + + resp = malloc(NS_MAXMSG); + if (resp == NULL) + goto cleanup; + + /* Now grovel the subdomains, hunting for an SOA answer or auth. */ + for (;;) { + /* Leading or inter-label '.' are skipped here. */ + while (*dname == '.') + dname++; + + /* Is there an SOA? */ + n = do_query(statp, dname, class, ns_t_soa, resp, &msg); + if (n < 0) { + DPRINTF(("get_soa: do_query('%s', %s) failed (%d)", + dname, p_class(class), n)); + goto cleanup; + } + if (n > 0) { + DPRINTF(("get_soa: CNAME or DNAME found")); + sect = ns_s_max, n = 0; + } else { + rcode = ns_msg_getflag(msg, ns_f_rcode); + ancount = ns_msg_count(msg, ns_s_an); + nscount = ns_msg_count(msg, ns_s_ns); + if (ancount > 0 && rcode == ns_r_noerror) + sect = ns_s_an, n = ancount; + else if (nscount > 0) + sect = ns_s_ns, n = nscount; + else + sect = ns_s_max, n = 0; + } + for (i = 0; i < n; i++) { + const char *t; + const u_char *rdata; + ns_rr rr; + + if (ns_parserr(&msg, sect, i, &rr) < 0) { + DPRINTF(("get_soa: ns_parserr(%s, %d) failed", + p_section(sect, ns_o_query), i)); + goto cleanup; + } + if (ns_rr_type(rr) == ns_t_cname || + ns_rr_type(rr) == ns_t_dname) + break; + if (ns_rr_type(rr) != ns_t_soa || + ns_rr_class(rr) != class) + continue; + t = ns_rr_name(rr); + switch (sect) { + case ns_s_an: + if (ns_samedomain(dname, t) == 0) { + DPRINTF( + ("get_soa: ns_samedomain('%s', '%s') == 0", + dname, t) + ); + errno = EPROTOTYPE; + goto cleanup; + } + break; + case ns_s_ns: + if (ns_samename(dname, t) == 1 || + ns_samedomain(dname, t) == 0) { + DPRINTF( + ("get_soa: ns_samename() || !ns_samedomain('%s', '%s')", + dname, t) + ); + errno = EPROTOTYPE; + goto cleanup; + } + break; + default: + abort(); + } + if (strlen(t) + 1 > zsize) { + DPRINTF(("get_soa: zname(%lu) too small (%lu)", + (unsigned long)zsize, + (unsigned long)strlen(t) + 1)); + errno = EMSGSIZE; + goto cleanup; + } + strcpy(zname, t); + rdata = ns_rr_rdata(rr); + if (ns_name_uncompress(resp, ns_msg_end(msg), rdata, + mname, msize) < 0) { + DPRINTF(("get_soa: ns_name_uncompress failed") + ); + goto cleanup; + } + if (save_ns(statp, &msg, ns_s_ns, + zname, class, opts, nsrrsp) < 0) { + DPRINTF(("get_soa: save_ns failed")); + goto cleanup; + } + free(resp); + return (0); + } + + /* If we're out of labels, then not even "." has an SOA! */ + if (*dname == '\0') + break; + + /* Find label-terminating "."; top of loop will skip it. */ + while (*dname != '.') { + if (*dname == '\\') + if (*++dname == '\0') { + errno = EMSGSIZE; + goto cleanup; + } + dname++; + } + } + DPRINTF(("get_soa: out of labels")); + errno = EDESTADDRREQ; + cleanup: + if (resp != NULL) + free(resp); + return (-1); +} + +static int +get_ns(res_state statp, const char *zname, ns_class class, int opts, + rrset_ns *nsrrsp) +{ + u_char *resp; + ns_msg msg; + int n; + + resp = malloc(NS_MAXMSG); + if (resp == NULL) + return (-1); + + /* Go and get the NS RRs for this zone. */ + n = do_query(statp, zname, class, ns_t_ns, resp, &msg); + if (n != 0) { + DPRINTF(("get_ns: do_query('%s', %s) failed (%d)", + zname, p_class(class), n)); + free(resp); + return (-1); + } + + /* Remember the NS RRs and associated A RRs that came back. */ + if (save_ns(statp, &msg, ns_s_an, zname, class, opts, nsrrsp) < 0) { + DPRINTF(("get_ns save_ns('%s', %s) failed", + zname, p_class(class))); + free(resp); + return (-1); + } + + free(resp); + return (0); +} + +static int +get_glue(res_state statp, ns_class class, int opts, rrset_ns *nsrrsp) { + rr_ns *nsrr, *nsrr_n; + u_char *resp; + + resp = malloc(NS_MAXMSG); + if (resp == NULL) + return(-1); + + /* Go and get the A RRs for each empty NS RR on our list. */ + for (nsrr = HEAD(*nsrrsp); nsrr != NULL; nsrr = nsrr_n) { + ns_msg msg; + int n; + + nsrr_n = NEXT(nsrr, link); + + if ((nsrr->flags & RR_NS_HAVE_V4) == 0) { + n = do_query(statp, nsrr->name, class, ns_t_a, + resp, &msg); + if (n < 0) { + DPRINTF( + ("get_glue: do_query('%s', %s') failed", + nsrr->name, p_class(class))); + goto cleanup; + } + if (n > 0) { + DPRINTF(( + "get_glue: do_query('%s', %s') CNAME or DNAME found", + nsrr->name, p_class(class))); + } + if (save_a(statp, &msg, ns_s_an, nsrr->name, class, + opts, nsrr) < 0) { + DPRINTF(("get_glue: save_r('%s', %s) failed", + nsrr->name, p_class(class))); + goto cleanup; + } + } + + if ((nsrr->flags & RR_NS_HAVE_V6) == 0) { + n = do_query(statp, nsrr->name, class, ns_t_aaaa, + resp, &msg); + if (n < 0) { + DPRINTF( + ("get_glue: do_query('%s', %s') failed", + nsrr->name, p_class(class))); + goto cleanup; + } + if (n > 0) { + DPRINTF(( + "get_glue: do_query('%s', %s') CNAME or DNAME found", + nsrr->name, p_class(class))); + } + if (save_a(statp, &msg, ns_s_an, nsrr->name, class, + opts, nsrr) < 0) { + DPRINTF(("get_glue: save_r('%s', %s) failed", + nsrr->name, p_class(class))); + goto cleanup; + } + } + + /* If it's still empty, it's just chaff. */ + if (EMPTY(nsrr->addrs)) { + DPRINTF(("get_glue: removing empty '%s' NS", + nsrr->name)); + free_nsrr(nsrrsp, nsrr); + } + } + free(resp); + return (0); + + cleanup: + free(resp); + return (-1); +} + +static int +save_ns(res_state statp, ns_msg *msg, ns_sect sect, + const char *owner, ns_class class, int opts, + rrset_ns *nsrrsp) +{ + int i; + + for (i = 0; i < ns_msg_count(*msg, sect); i++) { + char tname[MAXDNAME]; + const u_char *rdata; + rr_ns *nsrr; + ns_rr rr; + + if (ns_parserr(msg, sect, i, &rr) < 0) { + DPRINTF(("save_ns: ns_parserr(%s, %d) failed", + p_section(sect, ns_o_query), i)); + return (-1); + } + if (ns_rr_type(rr) != ns_t_ns || + ns_rr_class(rr) != class || + ns_samename(ns_rr_name(rr), owner) != 1) + continue; + nsrr = find_ns(nsrrsp, ns_rr_name(rr)); + if (nsrr == NULL) { + nsrr = malloc(sizeof *nsrr); + if (nsrr == NULL) { + DPRINTF(("save_ns: malloc failed")); + return (-1); + } + rdata = ns_rr_rdata(rr); + if (ns_name_uncompress(ns_msg_base(*msg), + ns_msg_end(*msg), rdata, + tname, sizeof tname) < 0) { + DPRINTF(("save_ns: ns_name_uncompress failed") + ); + free(nsrr); + return (-1); + } + nsrr->name = strdup(tname); + if (nsrr->name == NULL) { + DPRINTF(("save_ns: strdup failed")); + free(nsrr); + return (-1); + } + INIT_LINK(nsrr, link); + INIT_LIST(nsrr->addrs); + nsrr->flags = 0; + APPEND(*nsrrsp, nsrr, link); + } + if (save_a(statp, msg, ns_s_ar, + nsrr->name, class, opts, nsrr) < 0) { + DPRINTF(("save_ns: save_r('%s', %s) failed", + nsrr->name, p_class(class))); + return (-1); + } + } + return (0); +} + +static int +save_a(res_state statp, ns_msg *msg, ns_sect sect, + const char *owner, ns_class class, int opts, + rr_ns *nsrr) +{ + int i; + + for (i = 0; i < ns_msg_count(*msg, sect); i++) { + ns_rr rr; + rr_a *arr; + + if (ns_parserr(msg, sect, i, &rr) < 0) { + DPRINTF(("save_a: ns_parserr(%s, %d) failed", + p_section(sect, ns_o_query), i)); + return (-1); + } + if ((ns_rr_type(rr) != ns_t_a && + ns_rr_type(rr) != ns_t_aaaa) || + ns_rr_class(rr) != class || + ns_samename(ns_rr_name(rr), owner) != 1 || + ns_rr_rdlen(rr) != NS_INADDRSZ) + continue; + if ((opts & RES_IPV6ONLY) != 0 && ns_rr_type(rr) != ns_t_aaaa) + continue; + if ((opts & RES_IPV4ONLY) != 0 && ns_rr_type(rr) != ns_t_a) + continue; + arr = malloc(sizeof *arr); + if (arr == NULL) { + DPRINTF(("save_a: malloc failed")); + return (-1); + } + INIT_LINK(arr, link); + memset(&arr->addr, 0, sizeof(arr->addr)); + switch (ns_rr_type(rr)) { + case ns_t_a: + arr->addr.sin.sin_family = AF_INET; +#ifdef HAVE_SA_LEN + arr->addr.sin.sin_len = sizeof(arr->addr.sin); +#endif + memcpy(&arr->addr.sin.sin_addr, ns_rr_rdata(rr), + NS_INADDRSZ); + arr->addr.sin.sin_port = htons(NAMESERVER_PORT); + nsrr->flags |= RR_NS_HAVE_V4; + break; + case ns_t_aaaa: + arr->addr.sin6.sin6_family = AF_INET6; +#ifdef HAVE_SA_LEN + arr->addr.sin6.sin6_len = sizeof(arr->addr.sin6); +#endif + memcpy(&arr->addr.sin6.sin6_addr, ns_rr_rdata(rr), 16); + arr->addr.sin.sin_port = htons(NAMESERVER_PORT); + nsrr->flags |= RR_NS_HAVE_V6; + break; + default: + abort(); + } + APPEND(nsrr->addrs, arr, link); + } + return (0); +} + +static void +free_nsrrset(rrset_ns *nsrrsp) { + rr_ns *nsrr; + + while ((nsrr = HEAD(*nsrrsp)) != NULL) + free_nsrr(nsrrsp, nsrr); +} + +static void +free_nsrr(rrset_ns *nsrrsp, rr_ns *nsrr) { + rr_a *arr; + char *tmp; + + while ((arr = HEAD(nsrr->addrs)) != NULL) { + UNLINK(nsrr->addrs, arr, link); + free(arr); + } + DE_CONST(nsrr->name, tmp); + free(tmp); + UNLINK(*nsrrsp, nsrr, link); + free(nsrr); +} + +static rr_ns * +find_ns(rrset_ns *nsrrsp, const char *dname) { + rr_ns *nsrr; + + for (nsrr = HEAD(*nsrrsp); nsrr != NULL; nsrr = NEXT(nsrr, link)) + if (ns_samename(nsrr->name, dname) == 1) + return (nsrr); + return (NULL); +} + +static int +do_query(res_state statp, const char *dname, ns_class class, ns_type qtype, + u_char *resp, ns_msg *msg) +{ + u_char req[NS_PACKETSZ]; + int i, n; + + n = res_nmkquery(statp, ns_o_query, dname, class, qtype, + NULL, 0, NULL, req, NS_PACKETSZ); + if (n < 0) { + DPRINTF(("do_query: res_nmkquery failed")); + return (-1); + } + n = res_nsend(statp, req, n, resp, NS_MAXMSG); + if (n < 0) { + DPRINTF(("do_query: res_nsend failed")); + return (-1); + } + if (n == 0) { + DPRINTF(("do_query: res_nsend returned 0")); + errno = EMSGSIZE; + return (-1); + } + if (ns_initparse(resp, n, msg) < 0) { + DPRINTF(("do_query: ns_initparse failed")); + return (-1); + } + n = 0; + for (i = 0; i < ns_msg_count(*msg, ns_s_an); i++) { + ns_rr rr; + + if (ns_parserr(msg, ns_s_an, i, &rr) < 0) { + DPRINTF(("do_query: ns_parserr failed")); + return (-1); + } + n += (ns_rr_class(rr) == class && + (ns_rr_type(rr) == ns_t_cname || + ns_rr_type(rr) == ns_t_dname)); + } + return (n); +} + +static void +res_dprintf(const char *fmt, ...) { + va_list ap; + + va_start(ap, fmt); + fputs(";; res_findzonecut: ", stderr); + vfprintf(stderr, fmt, ap); + fputc('\n', stderr); + va_end(ap); +} + +/*! \file */ |