add getrrsetbyname(3) - API to retrieve arbitrary DNS records

1 files changed, 506 insertions, 0 deletions

diff --git a/src/lib/libc/net/getrrsetbyname.c b/src/lib/libc/net/getrrsetbyname.c
new file mode 100644
index 0000000000..cacf9157e7
--- /dev/null
+++ b/src/lib/libc/net/getrrsetbyname.c
@@ -0,0 +1,506 @@
+/* $Id: getrrsetbyname.c,v 1.1 2001/08/06 14:40:47 jakob Exp $ */
+
+/*
+ * Copyright (c) 2001 Jakob Schlyter. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+/*
+ * Portions Copyright (c) 1999-2001 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 INTERNET SOFTWARE CONSORTIUM
+ * DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL
+ * INTERNET SOFTWARE CONSORTIUM 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/types.h>
+#include <netinet/in.h>
+#include <arpa/nameser.h>
+#include <netdb.h>
+#include <resolv.h>
+#include <stdlib.h>
+#include <string.h>
+
+#define ANSWER_BUFFER_SIZE 1024*64
+
+
+struct dns_query {
+        char                    *name;
+        u_int16_t               type;
+        u_int16_t               class;
+        struct dns_query        *next;
+};
+
+struct dns_rr {
+        char                    *name;
+        u_int16_t               type;
+        u_int16_t               class;
+        u_int16_t               ttl;
+        u_int16_t               size;
+        void                    *rdata;
+        struct dns_rr           *next;
+};
+
+struct dns_response {
+        HEADER                  header;
+        struct dns_query        *query;
+        struct dns_rr           *answer;
+        struct dns_rr           *authority;
+        struct dns_rr           *additional;
+};
+
+static struct dns_response *parse_dns_response(const char *, int);
+static struct dns_query *parse_dns_qsection(const char *, int, const char **,
+    int);
+static struct dns_rr *parse_dns_rrsection(const char *, int, const char **,
+    int);
+
+static void free_dns_query(struct dns_query *);
+static void free_dns_rr(struct dns_rr *);
+static void free_dns_response(struct dns_response *);
+
+static int count_dns_rr(struct dns_rr *, u_int16_t, u_int16_t);
+
+int
+getrrsetbyname(const char *hostname, unsigned int rdclass,
+               unsigned int rdtype, unsigned int flags,
+               struct rrsetinfo **res)
+{
+        int result;
+        struct rrsetinfo *rrset = NULL;
+        struct dns_response *response;
+        struct dns_rr *rr;
+        struct rdatainfo *rdata;
+        unsigned length, index_ans, index_sig;
+        char answer[ANSWER_BUFFER_SIZE];
+
+        /* check for invalid class and type */
+        if (rdclass > 0xffff || rdtype > 0xffff) {
+                result = ERRSET_INVAL;
+                goto fail;
+        }
+
+        /* don't allow queries of class or type ANY */
+        if (rdclass == 0xff || rdtype == 0xff) {
+                result = ERRSET_INVAL;
+                goto fail;
+        }
+
+        /* don't allow flags yet, unimplemented */
+        if (flags) {
+                result = ERRSET_INVAL;
+                goto fail;
+        }
+
+        /* initialize resolver */
+        if ((_res.options & RES_INIT) == 0 && res_init() == -1) {
+                result = ERRSET_FAIL;
+                goto fail;
+        }
+
+#ifdef DEBUG
+        _res.options |= RES_DEBUG;
+#endif /* DEBUG */
+
+#ifdef RES_USE_DNSSEC
+        /* turn on DNSSEC if EDNS0 is configured */
+        if (_res.options & RES_USE_EDNS0)
+                _res.options |= RES_USE_DNSSEC;
+#endif /* RES_USE_DNSEC */
+
+        /* make query */
+        length = res_query(hostname, rdclass, rdtype, answer, sizeof(answer));
+        if (length < 0) {
+                switch(h_errno) {
+                case HOST_NOT_FOUND:
+                        result = ERRSET_NONAME;
+                        goto fail;
+                case NO_DATA:
+                        result = ERRSET_NODATA;
+                        goto fail;
+                default:
+                        result = ERRSET_FAIL;
+                        goto fail;
+                }
+        }
+
+        /* parse result */
+        response = parse_dns_response(answer, length);
+        if (response == NULL) {
+                result = ERRSET_FAIL;
+                goto fail;
+        }
+
+        if (response->header.qdcount != 1 ) {
+                result = ERRSET_FAIL;
+                goto fail;
+        }
+
+        /* initialize rrset */
+        rrset = calloc(1, sizeof(struct rrsetinfo));
+        if (rrset == NULL) {
+                result = ERRSET_NOMEMORY;
+                goto fail;
+        }
+        rrset->rri_rdclass = response->query->class;
+        rrset->rri_rdtype = response->query->type;
+        rrset->rri_ttl = response->answer->ttl;
+        rrset->rri_nrdatas = response->header.ancount;
+
+        /* check for authenticated data */
+        if (response->header.ad == 1)
+                rrset->rri_flags |= RRSET_VALIDATED;
+
+        /* copy name from answer section */
+        length = strlen(response->answer->name);
+        rrset->rri_name = malloc(length + 1);
+        if (rrset->rri_name == NULL) {
+                result = ERRSET_NOMEMORY;
+                goto fail;
+        }
+        strlcpy(rrset->rri_name, response->answer->name, length + 1);
+
+        /* count answers */
+        rrset->rri_nrdatas = count_dns_rr(response->answer, rrset->rri_rdclass,
+            rrset->rri_rdtype);
+        rrset->rri_nsigs = count_dns_rr(response->answer, rrset->rri_rdclass,
+            T_SIG);
+
+        /* allocate memory for answers */
+        rrset->rri_rdatas = calloc(rrset->rri_nrdatas,
+            sizeof(struct rdatainfo));
+        if (rrset->rri_rdatas == NULL) {
+                result = ERRSET_NOMEMORY;
+                goto fail;
+        }
+
+        /* allocate memory for signatures */
+        rrset->rri_sigs = calloc(rrset->rri_nsigs, sizeof(struct rdatainfo));
+        if (rrset->rri_sigs == NULL) {
+                result = ERRSET_NOMEMORY;
+                goto fail;
+        }
+
+        /* copy answers & signatures */
+        for (rr = response->answer, index_ans = 0, index_sig = 0;
+            rr; rr = rr->next) {
+
+                rdata = NULL;
+
+                if (rr->class == rrset->rri_rdclass &&
+                    rr->type  == rrset->rri_rdtype)
+                        rdata = &rrset->rri_rdatas[index_ans++];
+
+                if (rr->class == rrset->rri_rdclass &&
+                    rr->type  == T_SIG)
+                        rdata = &rrset->rri_sigs[index_sig++];
+
+                if (rdata) {
+                        rdata->rdi_length = rr->size;
+                        rdata->rdi_data   = malloc(rr->size);
+            
+                        if (rdata->rdi_data == NULL) {
+                                result = ERRSET_NOMEMORY;
+                                goto fail;
+                        }
+                        memcpy(rdata->rdi_data, rr->rdata, rr->size);
+                }
+        }
+
+        *res = rrset;
+        return (ERRSET_SUCCESS);
+
+fail:
+        if (rrset != NULL)
+                freerrset(rrset);
+        return (result);
+}
+
+void
+freerrset(struct rrsetinfo *rrset)
+{
+        u_int16_t i;
+
+        if (rrset == NULL) {
+                return;
+        }
+
+        for (i = 0; i < rrset->rri_nrdatas; i++) {
+                if (rrset->rri_rdatas[i].rdi_data == NULL)
+                        break;
+                free(rrset->rri_rdatas[i].rdi_data);
+        }
+        free(rrset->rri_rdatas);
+
+        for (i = 0; i < rrset->rri_nsigs; i++) {
+                if (rrset->rri_sigs[i].rdi_data == NULL)
+                        break;
+                free(rrset->rri_sigs[i].rdi_data);
+        }
+        free(rrset->rri_sigs);
+
+        free(rrset->rri_name);
+
+        free(rrset);
+}
+
+
+/* 
+ * DNS response parsing routines
+ */
+
+static struct dns_response *
+parse_dns_response(const char *answer, int size)
+{
+        struct dns_response *resp;
+        const char *cp;
+
+        /* allocate memory for the response */
+        resp = malloc(sizeof(*resp));
+        if (resp == NULL)
+                return (NULL);
+
+        /* initialize current pointer */
+        cp = answer;
+
+        /* copy header */
+        memcpy(&resp->header, cp, HFIXEDSZ);
+        cp += HFIXEDSZ;
+
+        /* fix header byte order */
+        resp->header.qdcount = ntohs(resp->header.qdcount);
+        resp->header.ancount = ntohs(resp->header.ancount);
+        resp->header.nscount = ntohs(resp->header.nscount);
+        resp->header.arcount = ntohs(resp->header.arcount);
+
+        /* there must be at least one query */
+        if (resp->header.qdcount < 1) {
+                free_dns_response(resp);
+                return (NULL);
+        }
+
+        /* parse query section */
+        resp->query = parse_dns_qsection(answer, size, &cp,
+            resp->header.qdcount);
+        if (resp->header.qdcount && resp->query == NULL) {
+                free_dns_response(resp);
+                return (NULL);
+        }
+
+        /* parse answer section */
+        resp->answer = parse_dns_rrsection(answer, size, &cp,
+            resp->header.ancount);
+        if (resp->header.ancount && resp->answer == NULL) {
+                free_dns_response(resp);
+                return (NULL);
+        }
+
+        /* parse authority section */
+        resp->authority = parse_dns_rrsection(answer, size, &cp,
+            resp->header.nscount);
+        if (resp->header.nscount && resp->authority == NULL) {
+                free_dns_response(resp);
+                return (NULL);
+        }
+
+        /* parse additional section */
+        resp->additional = parse_dns_rrsection(answer, size, &cp,
+            resp->header.arcount);
+        if (resp->header.arcount && resp->additional == NULL) {
+                free_dns_response(resp);
+                return (NULL);
+        }
+
+        return (resp);
+}
+
+static struct dns_query *
+parse_dns_qsection(const char *answer, int size, const char **cp, int count)
+{
+        struct dns_query *head, *curr, *prev;
+        int i, length;
+        char name[MAXDNAME];
+
+        for (i = 1, head = NULL, prev = NULL; i <= count; i++, prev = curr) {
+
+                /* allocate and initialize struct */
+                curr = calloc(1, sizeof(struct dns_query));
+                if (curr == NULL) {
+                        free_dns_query(head);
+                        return (NULL);
+                }
+                if (head == NULL)
+                        head = curr;
+                if (prev != NULL)
+                        prev->next = curr;
+
+                /* name */
+                length = dn_expand(answer, answer + size, *cp, name,
+                    sizeof(name));
+                if (length < 0) {
+                        free_dns_query(head);
+                        return (NULL);
+                }
+                curr->name = strdup(name);
+                if (curr->name == NULL) {
+                        free_dns_query(head);
+                        return (NULL);
+                }
+                *cp += length;
+
+                /* type */
+                curr->type = _getshort(*cp);
+                *cp += INT16SZ;
+
+                /* class */
+                curr->class = _getshort(*cp);
+                *cp += INT16SZ;
+        }
+
+        return (head);
+}
+
+static struct dns_rr *
+parse_dns_rrsection(const char *answer, int size, const char **cp, int count)
+{
+        struct dns_rr *head, *curr, *prev;
+        int i, length;
+        char name[MAXDNAME];
+
+        for (i = 1, head = NULL, prev = NULL; i <= count; i++, prev = curr) {
+
+                /* allocate and initialize struct */
+                curr = calloc(1, sizeof(struct dns_rr));
+                if (curr == NULL) {
+                        free_dns_rr(head);
+                        return (NULL);
+                }
+                if (head == NULL)
+                        head = curr;
+                if (prev != NULL)
+                        prev->next = curr;
+
+                /* name */
+                length = dn_expand(answer, answer + size, *cp, name,
+                    sizeof(name));
+                if (length < 0) {
+                        free_dns_rr(head);
+                        return (NULL);
+                }
+                curr->name = strdup(name);
+                if (curr->name == NULL) {
+                        free_dns_rr(head);
+                        return (NULL);
+                }
+                *cp += length;
+
+                /* type */
+                curr->type = _getshort(*cp);
+                *cp += INT16SZ;
+
+                /* class */
+                curr->class = _getshort(*cp);
+                *cp += INT16SZ;
+
+                /* ttl */
+                curr->ttl = _getlong(*cp);
+                *cp += INT32SZ;
+
+                /* rdata size */
+                curr->size = _getshort(*cp);
+                *cp += INT16SZ;
+
+                /* rdata itself */
+                curr->rdata = malloc(curr->size);
+                if (curr->rdata == NULL) {
+                        free_dns_rr(head);
+                        return (NULL);
+                }
+                memcpy(curr->rdata, *cp, curr->size);
+                *cp += curr->size;
+        }
+
+        return (head);
+}
+
+
+static void
+free_dns_query(struct dns_query *p)
+{
+        if (p == NULL)
+                return;
+
+        free(p->name);
+        free_dns_query(p->next);
+        free(p);
+}
+
+static void
+free_dns_rr(struct dns_rr *p)
+{
+        if (p == NULL)
+                return;
+
+        free(p->name);
+        free(p->rdata);
+        free_dns_rr(p->next);
+        free(p);
+}
+
+static void
+free_dns_response(struct dns_response *p)
+{
+        if (p == NULL)
+                return;
+
+        free_dns_query(p->query);
+        free_dns_rr(p->answer);
+        free_dns_rr(p->authority);
+        free_dns_rr(p->additional);
+        free(p);
+}
+
+static int
+count_dns_rr(struct dns_rr *p, u_int16_t class, u_int16_t type)
+{
+        int n = 0;
+
+        while(p) {
+                if (p->class == class && p->type == type)
+                        n++;
+                p = p->next;
+        };
+
+        return (n);
+}