/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/ /*** This file is part of systemd. Copyright 2014 Lennart Poettering systemd is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. systemd 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 Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with systemd; If not, see . ***/ #include "utf8.h" #include "util.h" #include "strv.h" #include "resolved-dns-domain.h" #include "resolved-dns-packet.h" int dns_packet_new(DnsPacket **ret, DnsProtocol protocol, size_t mtu) { DnsPacket *p; size_t a; assert(ret); if (mtu <= 0) a = DNS_PACKET_SIZE_START; else a = mtu; if (a < DNS_PACKET_HEADER_SIZE) a = DNS_PACKET_HEADER_SIZE; /* round up to next page size */ a = PAGE_ALIGN(ALIGN(sizeof(DnsPacket)) + a) - ALIGN(sizeof(DnsPacket)); /* make sure we never allocate more than useful */ if (a > DNS_PACKET_SIZE_MAX) a = DNS_PACKET_SIZE_MAX; p = malloc0(ALIGN(sizeof(DnsPacket)) + a); if (!p) return -ENOMEM; p->size = p->rindex = DNS_PACKET_HEADER_SIZE; p->allocated = a; p->protocol = protocol; p->n_ref = 1; *ret = p; return 0; } int dns_packet_new_query(DnsPacket **ret, DnsProtocol protocol, size_t mtu) { DnsPacket *p; DnsPacketHeader *h; int r; assert(ret); r = dns_packet_new(&p, protocol, mtu); if (r < 0) return r; h = DNS_PACKET_HEADER(p); if (protocol == DNS_PROTOCOL_LLMNR) h->flags = htobe16(DNS_PACKET_MAKE_FLAGS(0 /* qr */, 0 /* opcode */, 0 /* c */, 0 /* tc */, 0 /* t */, 0 /* ra */, 0 /* ad */, 0 /* cd */, 0 /* rcode */)); else h->flags = htobe16(DNS_PACKET_MAKE_FLAGS(0 /* qr */, 0 /* opcode */, 0 /* aa */, 0 /* tc */, 1 /* rd (ask for recursion) */, 0 /* ra */, 0 /* ad */, 0 /* cd */, 0 /* rcode */)); *ret = p; return 0; } DnsPacket *dns_packet_ref(DnsPacket *p) { if (!p) return NULL; assert(p->n_ref > 0); p->n_ref++; return p; } static void dns_packet_free(DnsPacket *p) { char *s; assert(p); dns_question_unref(p->question); dns_answer_unref(p->answer); while ((s = hashmap_steal_first_key(p->names))) free(s); hashmap_free(p->names); free(p->_data); free(p); } DnsPacket *dns_packet_unref(DnsPacket *p) { if (!p) return NULL; assert(p->n_ref > 0); if (p->n_ref == 1) dns_packet_free(p); else p->n_ref--; return NULL; } int dns_packet_validate(DnsPacket *p) { assert(p); if (p->size < DNS_PACKET_HEADER_SIZE) return -EBADMSG; if (p->size > DNS_PACKET_SIZE_MAX) return -EBADMSG; return 1; } int dns_packet_validate_reply(DnsPacket *p) { int r; assert(p); r = dns_packet_validate(p); if (r < 0) return r; if (DNS_PACKET_QR(p) != 1) return 0; if (DNS_PACKET_OPCODE(p) != 0) return -EBADMSG; /* RFC 4795, Section 2.1.1. says to discard all replies with QDCOUNT != 1 */ if (p->protocol == DNS_PROTOCOL_LLMNR && DNS_PACKET_QDCOUNT(p) != 1) return -EBADMSG; return 1; } int dns_packet_validate_query(DnsPacket *p) { int r; assert(p); r = dns_packet_validate(p); if (r < 0) return r; if (DNS_PACKET_QR(p) != 0) return 0; if (DNS_PACKET_OPCODE(p) != 0) return -EBADMSG; if (DNS_PACKET_TC(p)) return -EBADMSG; /* RFC 4795, Section 2.1.1. says to discard all queries with QDCOUNT != 1 */ if (p->protocol == DNS_PROTOCOL_LLMNR && DNS_PACKET_QDCOUNT(p) != 1) return -EBADMSG; /* RFC 4795, Section 2.1.1. says to discard all queries with ANCOUNT != 0 */ if (DNS_PACKET_ANCOUNT(p) > 0) return -EBADMSG; /* RFC 4795, Section 2.1.1. says to discard all queries with NSCOUNT != 0 */ if (DNS_PACKET_NSCOUNT(p) > 0) return -EBADMSG; return 1; } static int dns_packet_extend(DnsPacket *p, size_t add, void **ret, size_t *start) { assert(p); if (p->size + add > p->allocated) { size_t a; a = PAGE_ALIGN((p->size + add) * 2); if (a > DNS_PACKET_SIZE_MAX) a = DNS_PACKET_SIZE_MAX; if (p->size + add > a) return -EMSGSIZE; if (p->_data) { void *d; d = realloc(p->_data, a); if (!d) return -ENOMEM; p->_data = d; } else { p->_data = malloc(a); if (!p->_data) return -ENOMEM; memcpy(p->_data, (uint8_t*) p + ALIGN(sizeof(DnsPacket)), p->size); memzero((uint8_t*) p->_data + p->size, a - p->size); } p->allocated = a; } if (start) *start = p->size; if (ret) *ret = (uint8_t*) DNS_PACKET_DATA(p) + p->size; p->size += add; return 0; } static void dns_packet_truncate(DnsPacket *p, size_t sz) { Iterator i; char *s; void *n; assert(p); if (p->size <= sz) return; HASHMAP_FOREACH_KEY(s, n, p->names, i) { if (PTR_TO_SIZE(n) < sz) continue; hashmap_remove(p->names, s); free(s); } p->size = sz; } int dns_packet_append_blob(DnsPacket *p, const void *d, size_t l, size_t *start) { void *q; int r; assert(p); r = dns_packet_extend(p, l, &q, start); if (r < 0) return r; memcpy(q, d, l); return 0; } int dns_packet_append_uint8(DnsPacket *p, uint8_t v, size_t *start) { void *d; int r; assert(p); r = dns_packet_extend(p, sizeof(uint8_t), &d, start); if (r < 0) return r; ((uint8_t*) d)[0] = v; return 0; } int dns_packet_append_uint16(DnsPacket *p, uint16_t v, size_t *start) { void *d; int r; assert(p); r = dns_packet_extend(p, sizeof(uint16_t), &d, start); if (r < 0) return r; ((uint8_t*) d)[0] = (uint8_t) (v >> 8); ((uint8_t*) d)[1] = (uint8_t) v; return 0; } int dns_packet_append_uint32(DnsPacket *p, uint32_t v, size_t *start) { void *d; int r; assert(p); r = dns_packet_extend(p, sizeof(uint32_t), &d, start); if (r < 0) return r; ((uint8_t*) d)[0] = (uint8_t) (v >> 24); ((uint8_t*) d)[1] = (uint8_t) (v >> 16); ((uint8_t*) d)[2] = (uint8_t) (v >> 8); ((uint8_t*) d)[3] = (uint8_t) v; return 0; } int dns_packet_append_string(DnsPacket *p, const char *s, size_t *start) { void *d; size_t l; int r; assert(p); assert(s); l = strlen(s); if (l > 255) return -E2BIG; r = dns_packet_extend(p, 1 + l, &d, start); if (r < 0) return r; ((uint8_t*) d)[0] = (uint8_t) l; memcpy(((uint8_t*) d) + 1, s, l); return 0; } int dns_packet_append_label(DnsPacket *p, const char *d, size_t l, size_t *start) { void *w; int r; assert(p); assert(d); if (l > DNS_LABEL_MAX) return -E2BIG; r = dns_packet_extend(p, 1 + l, &w, start); if (r < 0) return r; ((uint8_t*) w)[0] = (uint8_t) l; memcpy(((uint8_t*) w) + 1, d, l); return 0; } int dns_packet_append_name(DnsPacket *p, const char *name, size_t *start) { size_t saved_size; int r; assert(p); assert(name); saved_size = p->size; while (*name) { _cleanup_free_ char *s = NULL; char label[DNS_LABEL_MAX]; size_t n; int k; n = PTR_TO_SIZE(hashmap_get(p->names, name)); if (n > 0) { assert(n < p->size); if (n < 0x4000) { r = dns_packet_append_uint16(p, 0xC000 | n, NULL); if (r < 0) goto fail; goto done; } } s = strdup(name); if (!s) { r = -ENOMEM; goto fail; } r = dns_label_unescape(&name, label, sizeof(label)); if (r < 0) goto fail; if (p->protocol == DNS_PROTOCOL_DNS) k = dns_label_apply_idna(label, r, label, sizeof(label)); else k = dns_label_undo_idna(label, r, label, sizeof(label)); if (k < 0) { r = k; goto fail; } if (k > 0) r = k; r = dns_packet_append_label(p, label, r, &n); if (r < 0) goto fail; r = hashmap_ensure_allocated(&p->names, dns_name_hash_func, dns_name_compare_func); if (r < 0) goto fail; r = hashmap_put(p->names, s, SIZE_TO_PTR(n)); if (r < 0) goto fail; s = NULL; } r = dns_packet_append_uint8(p, 0, NULL); if (r < 0) return r; done: if (start) *start = saved_size; return 0; fail: dns_packet_truncate(p, saved_size); return r; } int dns_packet_append_key(DnsPacket *p, const DnsResourceKey *k, size_t *start) { size_t saved_size; int r; assert(p); assert(k); saved_size = p->size; r = dns_packet_append_name(p, DNS_RESOURCE_KEY_NAME(k), NULL); if (r < 0) goto fail; r = dns_packet_append_uint16(p, k->type, NULL); if (r < 0) goto fail; r = dns_packet_append_uint16(p, k->class, NULL); if (r < 0) goto fail; if (start) *start = saved_size; return 0; fail: dns_packet_truncate(p, saved_size); return r; } int dns_packet_append_rr(DnsPacket *p, const DnsResourceRecord *rr, size_t *start) { size_t saved_size, rdlength_offset, end, rdlength; int r; assert(p); assert(rr); saved_size = p->size; r = dns_packet_append_key(p, rr->key, NULL); if (r < 0) goto fail; r = dns_packet_append_uint32(p, rr->ttl, NULL); if (r < 0) goto fail; /* Initially we write 0 here */ r = dns_packet_append_uint16(p, 0, &rdlength_offset); if (r < 0) goto fail; switch (rr->unparseable ? _DNS_TYPE_INVALID : rr->key->type) { case DNS_TYPE_SRV: r = dns_packet_append_uint16(p, rr->srv.priority, NULL); if (r < 0) goto fail; r = dns_packet_append_uint16(p, rr->srv.weight, NULL); if (r < 0) goto fail; r = dns_packet_append_uint16(p, rr->srv.port, NULL); if (r < 0) goto fail; r = dns_packet_append_name(p, rr->srv.name, NULL); break; case DNS_TYPE_PTR: case DNS_TYPE_NS: case DNS_TYPE_CNAME: case DNS_TYPE_DNAME: r = dns_packet_append_name(p, rr->ptr.name, NULL); break; case DNS_TYPE_HINFO: r = dns_packet_append_string(p, rr->hinfo.cpu, NULL); if (r < 0) goto fail; r = dns_packet_append_string(p, rr->hinfo.os, NULL); break; case DNS_TYPE_SPF: /* exactly the same as TXT */ case DNS_TYPE_TXT: { char **s; STRV_FOREACH(s, rr->txt.strings) { r = dns_packet_append_string(p, *s, NULL); if (r < 0) goto fail; } r = 0; break; } case DNS_TYPE_A: r = dns_packet_append_blob(p, &rr->a.in_addr, sizeof(struct in_addr), NULL); break; case DNS_TYPE_AAAA: r = dns_packet_append_blob(p, &rr->aaaa.in6_addr, sizeof(struct in6_addr), NULL); break; case DNS_TYPE_SOA: r = dns_packet_append_name(p, rr->soa.mname, NULL); if (r < 0) goto fail; r = dns_packet_append_name(p, rr->soa.rname, NULL); if (r < 0) goto fail; r = dns_packet_append_uint32(p, rr->soa.serial, NULL); if (r < 0) goto fail; r = dns_packet_append_uint32(p, rr->soa.refresh, NULL); if (r < 0) goto fail; r = dns_packet_append_uint32(p, rr->soa.retry, NULL); if (r < 0) goto fail; r = dns_packet_append_uint32(p, rr->soa.expire, NULL); if (r < 0) goto fail; r = dns_packet_append_uint32(p, rr->soa.minimum, NULL); break; case DNS_TYPE_MX: r = dns_packet_append_uint16(p, rr->mx.priority, NULL); if (r < 0) goto fail; r = dns_packet_append_name(p, rr->mx.exchange, NULL); break; case DNS_TYPE_LOC: r = dns_packet_append_uint8(p, rr->loc.version, NULL); if (r < 0) goto fail; r = dns_packet_append_uint8(p, rr->loc.size, NULL); if (r < 0) goto fail; r = dns_packet_append_uint8(p, rr->loc.horiz_pre, NULL); if (r < 0) goto fail; r = dns_packet_append_uint8(p, rr->loc.vert_pre, NULL); if (r < 0) goto fail; r = dns_packet_append_uint32(p, rr->loc.latitude, NULL); if (r < 0) goto fail; r = dns_packet_append_uint32(p, rr->loc.longitude, NULL); if (r < 0) goto fail; r = dns_packet_append_uint32(p, rr->loc.altitude, NULL); break; case DNS_TYPE_SSHFP: r = dns_packet_append_uint8(p, rr->sshfp.algorithm, NULL); if (r < 0) goto fail; r = dns_packet_append_uint8(p, rr->sshfp.fptype, NULL); if (r < 0) goto fail; r = dns_packet_append_blob(p, rr->sshfp.key, rr->sshfp.key_size, NULL); break; case DNS_TYPE_DNSKEY: r = dns_packet_append_uint16(p, dnskey_to_flags(rr), NULL); if (r < 0) goto fail; r = dns_packet_append_uint8(p, 3u, NULL); if (r < 0) goto fail; r = dns_packet_append_uint8(p, rr->dnskey.algorithm, NULL); if (r < 0) goto fail; r = dns_packet_append_blob(p, rr->dnskey.key, rr->dnskey.key_size, NULL); break; case _DNS_TYPE_INVALID: /* unparseable */ default: r = dns_packet_append_blob(p, rr->generic.data, rr->generic.size, NULL); break; } if (r < 0) goto fail; /* Let's calculate the actual data size and update the field */ rdlength = p->size - rdlength_offset - sizeof(uint16_t); if (rdlength > 0xFFFF) { r = ENOSPC; goto fail; } end = p->size; p->size = rdlength_offset; r = dns_packet_append_uint16(p, rdlength, NULL); if (r < 0) goto fail; p->size = end; if (start) *start = saved_size; return 0; fail: dns_packet_truncate(p, saved_size); return r; } int dns_packet_read(DnsPacket *p, size_t sz, const void **ret, size_t *start) { assert(p); if (p->rindex + sz > p->size) return -EMSGSIZE; if (ret) *ret = (uint8_t*) DNS_PACKET_DATA(p) + p->rindex; if (start) *start = p->rindex; p->rindex += sz; return 0; } void dns_packet_rewind(DnsPacket *p, size_t idx) { assert(p); assert(idx <= p->size); assert(idx >= DNS_PACKET_HEADER_SIZE); p->rindex = idx; } int dns_packet_read_blob(DnsPacket *p, void *d, size_t sz, size_t *start) { const void *q; int r; assert(p); assert(d); r = dns_packet_read(p, sz, &q, start); if (r < 0) return r; memcpy(d, q, sz); return 0; } int dns_packet_read_uint8(DnsPacket *p, uint8_t *ret, size_t *start) { const void *d; int r; assert(p); r = dns_packet_read(p, sizeof(uint8_t), &d, start); if (r < 0) return r; *ret = ((uint8_t*) d)[0]; return 0; } int dns_packet_read_uint16(DnsPacket *p, uint16_t *ret, size_t *start) { const void *d; int r; assert(p); r = dns_packet_read(p, sizeof(uint16_t), &d, start); if (r < 0) return r; *ret = (((uint16_t) ((uint8_t*) d)[0]) << 8) | ((uint16_t) ((uint8_t*) d)[1]); return 0; } int dns_packet_read_uint32(DnsPacket *p, uint32_t *ret, size_t *start) { const void *d; int r; assert(p); r = dns_packet_read(p, sizeof(uint32_t), &d, start); if (r < 0) return r; *ret = (((uint32_t) ((uint8_t*) d)[0]) << 24) | (((uint32_t) ((uint8_t*) d)[1]) << 16) | (((uint32_t) ((uint8_t*) d)[2]) << 8) | ((uint32_t) ((uint8_t*) d)[3]); return 0; } int dns_packet_read_string(DnsPacket *p, char **ret, size_t *start) { size_t saved_rindex; const void *d; char *t; uint8_t c; int r; assert(p); saved_rindex = p->rindex; r = dns_packet_read_uint8(p, &c, NULL); if (r < 0) goto fail; r = dns_packet_read(p, c, &d, NULL); if (r < 0) goto fail; if (memchr(d, 0, c)) { r = -EBADMSG; goto fail; } t = strndup(d, c); if (!t) { r = -ENOMEM; goto fail; } if (!utf8_is_valid(t)) { free(t); r = -EBADMSG; goto fail; } *ret = t; if (start) *start = saved_rindex; return 0; fail: dns_packet_rewind(p, saved_rindex); return r; } int dns_packet_read_name(DnsPacket *p, char **_ret, size_t *start) { size_t saved_rindex, after_rindex = 0; _cleanup_free_ char *ret = NULL; size_t n = 0, allocated = 0; bool first = true; int r; assert(p); assert(_ret); saved_rindex = p->rindex; for (;;) { uint8_t c, d; r = dns_packet_read_uint8(p, &c, NULL); if (r < 0) goto fail; if (c == 0) /* End of name */ break; else if (c <= 63) { _cleanup_free_ char *t = NULL; const char *label; /* Literal label */ r = dns_packet_read(p, c, (const void**) &label, NULL); if (r < 0) goto fail; r = dns_label_escape(label, c, &t); if (r < 0) goto fail; if (!GREEDY_REALLOC(ret, allocated, n + !first + strlen(t) + 1)) { r = -ENOMEM; goto fail; } if (!first) ret[n++] = '.'; else first = false; memcpy(ret + n, t, r); n += r; continue; } else if ((c & 0xc0) == 0xc0) { uint16_t ptr; /* Pointer */ r = dns_packet_read_uint8(p, &d, NULL); if (r < 0) goto fail; ptr = (uint16_t) (c & ~0xc0) << 8 | (uint16_t) d; if (ptr < DNS_PACKET_HEADER_SIZE || ptr >= saved_rindex) { r = -EBADMSG; goto fail; } if (after_rindex == 0) after_rindex = p->rindex; p->rindex = ptr; } else goto fail; } if (!GREEDY_REALLOC(ret, allocated, n + 1)) { r = -ENOMEM; goto fail; } ret[n] = 0; if (after_rindex != 0) p->rindex= after_rindex; *_ret = ret; ret = NULL; if (start) *start = saved_rindex; return 0; fail: dns_packet_rewind(p, saved_rindex); return r; } int dns_packet_read_key(DnsPacket *p, DnsResourceKey **ret, size_t *start) { _cleanup_free_ char *name = NULL; uint16_t class, type; DnsResourceKey *key; size_t saved_rindex; int r; assert(p); assert(ret); saved_rindex = p->rindex; r = dns_packet_read_name(p, &name, NULL); if (r < 0) goto fail; r = dns_packet_read_uint16(p, &type, NULL); if (r < 0) goto fail; r = dns_packet_read_uint16(p, &class, NULL); if (r < 0) goto fail; key = dns_resource_key_new_consume(class, type, name); if (!key) { r = -ENOMEM; goto fail; } name = NULL; *ret = key; if (start) *start = saved_rindex; return 0; fail: dns_packet_rewind(p, saved_rindex); return r; } static int dns_packet_read_public_key(DnsPacket *p, size_t length, void **dp, size_t *lengthp, size_t *start) { int r; const void *d; void *d2; r = dns_packet_read(p, length, &d, NULL); if (r < 0) return r; d2 = memdup(d, length); if (!d2) return -ENOMEM; *dp = d2; *lengthp = length; return 0; } static bool loc_size_ok(uint8_t size) { uint8_t m = size >> 4, e = size & 0xF; return m <= 9 && e <= 9 && (m > 0 || e == 0); } static int dnskey_parse_flags(DnsResourceRecord *rr, uint16_t flags) { if (flags & ~(DNSKEY_FLAG_SEP | DNSKEY_FLAG_ZONE_KEY)) return -EBADMSG; rr->dnskey.zone_key_flag = flags & DNSKEY_FLAG_ZONE_KEY; rr->dnskey.sep_flag = flags & DNSKEY_FLAG_SEP; return 0; } int dns_packet_read_rr(DnsPacket *p, DnsResourceRecord **ret, size_t *start) { _cleanup_(dns_resource_record_unrefp) DnsResourceRecord *rr = NULL; _cleanup_(dns_resource_key_unrefp) DnsResourceKey *key = NULL; size_t saved_rindex, offset; uint16_t rdlength; const void *d; int r; assert(p); assert(ret); saved_rindex = p->rindex; r = dns_packet_read_key(p, &key, NULL); if (r < 0) goto fail; if (key->class == DNS_CLASS_ANY || key->type == DNS_TYPE_ANY) { r = -EBADMSG; goto fail; } rr = dns_resource_record_new(key); if (!rr) { r = -ENOMEM; goto fail; } r = dns_packet_read_uint32(p, &rr->ttl, NULL); if (r < 0) goto fail; r = dns_packet_read_uint16(p, &rdlength, NULL); if (r < 0) goto fail; if (p->rindex + rdlength > p->size) { r = -EBADMSG; goto fail; } offset = p->rindex; switch (rr->key->type) { case DNS_TYPE_SRV: r = dns_packet_read_uint16(p, &rr->srv.priority, NULL); if (r < 0) goto fail; r = dns_packet_read_uint16(p, &rr->srv.weight, NULL); if (r < 0) goto fail; r = dns_packet_read_uint16(p, &rr->srv.port, NULL); if (r < 0) goto fail; r = dns_packet_read_name(p, &rr->srv.name, NULL); break; case DNS_TYPE_PTR: case DNS_TYPE_NS: case DNS_TYPE_CNAME: case DNS_TYPE_DNAME: r = dns_packet_read_name(p, &rr->ptr.name, NULL); break; case DNS_TYPE_HINFO: r = dns_packet_read_string(p, &rr->hinfo.cpu, NULL); if (r < 0) goto fail; r = dns_packet_read_string(p, &rr->hinfo.os, NULL); break; case DNS_TYPE_SPF: /* exactly the same as TXT */ case DNS_TYPE_TXT: { char *s; while (p->rindex < offset + rdlength) { r = dns_packet_read_string(p, &s, NULL); if (r < 0) goto fail; r = strv_consume(&rr->txt.strings, s); if (r < 0) goto fail; } r = 0; break; } case DNS_TYPE_A: r = dns_packet_read_blob(p, &rr->a.in_addr, sizeof(struct in_addr), NULL); break; case DNS_TYPE_AAAA: r = dns_packet_read_blob(p, &rr->aaaa.in6_addr, sizeof(struct in6_addr), NULL); break; case DNS_TYPE_SOA: r = dns_packet_read_name(p, &rr->soa.mname, NULL); if (r < 0) goto fail; r = dns_packet_read_name(p, &rr->soa.rname, NULL); if (r < 0) goto fail; r = dns_packet_read_uint32(p, &rr->soa.serial, NULL); if (r < 0) goto fail; r = dns_packet_read_uint32(p, &rr->soa.refresh, NULL); if (r < 0) goto fail; r = dns_packet_read_uint32(p, &rr->soa.retry, NULL); if (r < 0) goto fail; r = dns_packet_read_uint32(p, &rr->soa.expire, NULL); if (r < 0) goto fail; r = dns_packet_read_uint32(p, &rr->soa.minimum, NULL); break; case DNS_TYPE_MX: r = dns_packet_read_uint16(p, &rr->mx.priority, NULL); if (r < 0) goto fail; r = dns_packet_read_name(p, &rr->mx.exchange, NULL); break; case DNS_TYPE_LOC: { uint8_t t; size_t pos; r = dns_packet_read_uint8(p, &t, &pos); if (r < 0) goto fail; if (t == 0) { rr->loc.version = t; r = dns_packet_read_uint8(p, &rr->loc.size, NULL); if (r < 0) goto fail; if (!loc_size_ok(rr->loc.size)) { r = -EBADMSG; goto fail; } r = dns_packet_read_uint8(p, &rr->loc.horiz_pre, NULL); if (r < 0) goto fail; if (!loc_size_ok(rr->loc.horiz_pre)) { r = -EBADMSG; goto fail; } r = dns_packet_read_uint8(p, &rr->loc.vert_pre, NULL); if (r < 0) goto fail; if (!loc_size_ok(rr->loc.vert_pre)) { r = -EBADMSG; goto fail; } r = dns_packet_read_uint32(p, &rr->loc.latitude, NULL); if (r < 0) goto fail; r = dns_packet_read_uint32(p, &rr->loc.longitude, NULL); if (r < 0) goto fail; r = dns_packet_read_uint32(p, &rr->loc.altitude, NULL); if (r < 0) goto fail; break; } else { dns_packet_rewind(p, pos); rr->unparseable = true; goto unparseable; } } case DNS_TYPE_SSHFP: r = dns_packet_read_uint8(p, &rr->sshfp.algorithm, NULL); if (r < 0) goto fail; r = dns_packet_read_uint8(p, &rr->sshfp.fptype, NULL); if (r < 0) goto fail; r = dns_packet_read_public_key(p, rdlength - 2, &rr->sshfp.key, &rr->sshfp.key_size, NULL); break; case DNS_TYPE_DNSKEY: { uint16_t flags; uint8_t proto; r = dns_packet_read_uint16(p, &flags, NULL); if (r < 0) goto fail; r = dnskey_parse_flags(rr, flags); if (r < 0) goto fail; r = dns_packet_read_uint8(p, &proto, NULL); if (r < 0) goto fail; /* protocol is required to be always 3 */ if (proto != 3) { r = -EBADMSG; goto fail; } r = dns_packet_read_uint8(p, &rr->dnskey.algorithm, NULL); if (r < 0) goto fail; r = dns_packet_read_public_key(p, rdlength - 4, &rr->dnskey.key, &rr->dnskey.key_size, NULL); break; } default: unparseable: r = dns_packet_read(p, rdlength, &d, NULL); if (r < 0) goto fail; rr->generic.data = memdup(d, rdlength); if (!rr->generic.data) { r = -ENOMEM; goto fail; } rr->generic.size = rdlength; break; } if (r < 0) goto fail; if (p->rindex != offset + rdlength) { r = -EBADMSG; goto fail; } *ret = rr; rr = NULL; if (start) *start = saved_rindex; return 0; fail: dns_packet_rewind(p, saved_rindex); return r; } int dns_packet_extract(DnsPacket *p) { _cleanup_(dns_question_unrefp) DnsQuestion *question = NULL; _cleanup_(dns_answer_unrefp) DnsAnswer *answer = NULL; size_t saved_rindex; unsigned n, i; int r; saved_rindex = p->rindex; dns_packet_rewind(p, DNS_PACKET_HEADER_SIZE); n = DNS_PACKET_QDCOUNT(p); if (n > 0) { question = dns_question_new(n); if (!question) { r = -ENOMEM; goto finish; } for (i = 0; i < n; i++) { _cleanup_(dns_resource_key_unrefp) DnsResourceKey *key = NULL; r = dns_packet_read_key(p, &key, NULL); if (r < 0) goto finish; r = dns_question_add(question, key); if (r < 0) goto finish; } } n = DNS_PACKET_RRCOUNT(p); if (n > 0) { answer = dns_answer_new(n); if (!answer) { r = -ENOMEM; goto finish; } for (i = 0; i < n; i++) { _cleanup_(dns_resource_record_unrefp) DnsResourceRecord *rr = NULL; r = dns_packet_read_rr(p, &rr, NULL); if (r < 0) goto finish; r = dns_answer_add(answer, rr); if (r < 0) goto finish; } } p->question = question; question = NULL; p->answer = answer; answer = NULL; r = 0; finish: p->rindex = saved_rindex; return r; } static const char* const dns_rcode_table[_DNS_RCODE_MAX_DEFINED] = { [DNS_RCODE_SUCCESS] = "SUCCESS", [DNS_RCODE_FORMERR] = "FORMERR", [DNS_RCODE_SERVFAIL] = "SERVFAIL", [DNS_RCODE_NXDOMAIN] = "NXDOMAIN", [DNS_RCODE_NOTIMP] = "NOTIMP", [DNS_RCODE_REFUSED] = "REFUSED", [DNS_RCODE_YXDOMAIN] = "YXDOMAIN", [DNS_RCODE_YXRRSET] = "YRRSET", [DNS_RCODE_NXRRSET] = "NXRRSET", [DNS_RCODE_NOTAUTH] = "NOTAUTH", [DNS_RCODE_NOTZONE] = "NOTZONE", [DNS_RCODE_BADVERS] = "BADVERS", [DNS_RCODE_BADKEY] = "BADKEY", [DNS_RCODE_BADTIME] = "BADTIME", [DNS_RCODE_BADMODE] = "BADMODE", [DNS_RCODE_BADNAME] = "BADNAME", [DNS_RCODE_BADALG] = "BADALG", [DNS_RCODE_BADTRUNC] = "BADTRUNC", }; DEFINE_STRING_TABLE_LOOKUP(dns_rcode, int); static const char* const dns_protocol_table[_DNS_PROTOCOL_MAX] = { [DNS_PROTOCOL_DNS] = "dns", [DNS_PROTOCOL_MDNS] = "mdns", [DNS_PROTOCOL_LLMNR] = "llmnr", }; DEFINE_STRING_TABLE_LOOKUP(dns_protocol, DnsProtocol);