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Diffstat (limited to 'src/libknot/packet/rrset-wire.c')
| -rw-r--r-- | src/libknot/packet/rrset-wire.c | 727 |
1 files changed, 727 insertions, 0 deletions
diff --git a/src/libknot/packet/rrset-wire.c b/src/libknot/packet/rrset-wire.c new file mode 100644 index 0000000..2b02969 --- /dev/null +++ b/src/libknot/packet/rrset-wire.c @@ -0,0 +1,727 @@ +/* Copyright (C) 2021 CZ.NIC, z.s.p.o. <knot-dns@labs.nic.cz> + + This program is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation, either version 3 of the License, or + (at your option) any later version. + + This program 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 General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see <https://www.gnu.org/licenses/>. + */ + +#include <assert.h> + +#include "libknot/attribute.h" +#include "libknot/consts.h" +#include "libknot/descriptor.h" +#include "libknot/packet/pkt.h" +#include "libknot/packet/rrset-wire.h" +#include "libknot/rrtype/naptr.h" +#include "libknot/rrtype/rrsig.h" +#include "libknot/rrtype/soa.h" +#include "contrib/macros.h" +#include "contrib/mempattern.h" +#include "contrib/tolower.h" +#include "contrib/wire_ctx.h" + +/*! + * \brief Get maximal size of a domain name in a wire with given capacity. + */ +static uint16_t dname_max(size_t wire_avail) +{ + return MIN(wire_avail, KNOT_DNAME_MAXLEN); +} + +/*! + * \brief Compares two domain name labels. + * + * \param label1 First label. + * \param label2 Second label (may be in upper-case). + * + * \retval true if the labels are identical + * \retval false if the labels are NOT identical + */ +static bool label_is_equal(const uint8_t *label1, const uint8_t *label2) +{ + assert(label1 && label2); + + if (*label1 != *label2) { + return false; + } + + uint8_t len = *label1; + for (uint8_t i = 1; i <= len; i++) { + if (label1[i] != knot_tolower(label2[i])) { + return false; + } + } + + return true; +} + +/*! + * Case insensitive comparison of two dnames in wire format. + * The second name may be compressed in a supplied wire. + */ +static bool dname_equal_wire(const knot_dname_t *d1, const knot_dname_t *d2, + const uint8_t *wire) +{ + assert(d1); + assert(d2); + + d2 = knot_wire_seek_label(d2, wire); + + while (*d1 != '\0' || *d2 != '\0') { + if (!label_is_equal(d1, d2)) { + return false; + } + d1 = knot_wire_next_label(d1, NULL); + d2 = knot_wire_next_label(d2, wire); + } + + return true; +} + +static uint16_t compr_get_ptr(knot_compr_t *compr, uint16_t hint) +{ + if (compr == NULL) { + return 0; + } + + return knot_compr_hint(compr->rrinfo, hint); +} + +static void compr_set_ptr(knot_compr_t *compr, uint16_t hint, + const uint8_t *written_at, uint16_t written_size) +{ + if (compr == NULL) { + return; + } + + assert(written_at >= compr->wire); + + uint16_t offset = written_at - compr->wire; + + if (knot_wire_is_pointer(written_at)) { + offset = knot_wire_get_pointer(written_at); + } + + knot_compr_hint_set(compr->rrinfo, hint, offset, written_size); +} + +static int write_rdata_fixed(const uint8_t **src, size_t *src_avail, + uint8_t **dst, size_t *dst_avail, size_t size) +{ + assert(src && *src); + assert(src_avail); + assert(dst && *dst); + assert(dst_avail); + + // Check input/output buffer boundaries. + if (size > *src_avail) { + return KNOT_EMALF; + } + + if (size > *dst_avail) { + return KNOT_ESPACE; + } + + // Data binary copy. + memcpy(*dst, *src, size); + + // Update buffers. + *src += size; + *src_avail -= size; + + *dst += size; + *dst_avail -= size; + + return KNOT_EOK; +} + +static int write_rdata_naptr_header(const uint8_t **src, size_t *src_avail, + uint8_t **dst, size_t *dst_avail) +{ + assert(src && *src); + assert(src_avail); + assert(dst && *dst); + assert(dst_avail); + + int ret = knot_naptr_header_size(*src, *src + *src_avail); + if (ret < 0) { + return ret; + } + + // Copy the data. + return write_rdata_fixed(src, src_avail, dst, dst_avail, ret); +} + +/*! \brief Helper for \ref compr_put_dname, writes label(s) with size checks. */ +#define WRITE_LABEL(dst, written, label, max, len) \ + if ((written) + (len) > (max)) { \ + return KNOT_ESPACE; \ + } else { \ + memcpy((dst) + (written), (label), (len)); \ + written += (len); \ + } + +/*! + * \brief Write compressed domain name to the destination wire. + * + * \param dname Name to be written. + * \param dst Destination wire. + * \param max Maximum number of bytes available. + * \param compr Compression context (NULL for no compression) + * \return Number of written bytes or an error. + */ +static int compr_put_dname(const knot_dname_t *dname, uint8_t *dst, uint16_t max, + knot_compr_t *compr) +{ + assert(dname && dst); + + // Write uncompressible names directly (zero label dname). + if (compr == NULL || *dname == '\0') { + return knot_dname_to_wire(dst, dname, max); + } + + // Get number of labels (should not be a zero label dname). + size_t name_labels = knot_dname_labels(dname, NULL); + assert(name_labels > 0); + + // Suffix must not be longer than whole name. + const knot_dname_t *suffix = compr->wire + compr->suffix.pos; + int suffix_labels = compr->suffix.labels; + while (suffix_labels > name_labels) { + suffix = knot_wire_next_label(suffix, compr->wire); + --suffix_labels; + } + + // Suffix is shorter than name, write labels until aligned. + uint8_t orig_labels = name_labels; + uint16_t written = 0; + while (name_labels > suffix_labels) { + WRITE_LABEL(dst, written, dname, max, (*dname + 1)); + dname = knot_wire_next_label(dname, NULL); + --name_labels; + } + + // Label count is now equal. + assert(name_labels == suffix_labels); + const knot_dname_t *match_begin = dname; + const knot_dname_t *compr_ptr = suffix; + while (dname[0] != '\0') { + // Next labels. + const knot_dname_t *next_dname = knot_wire_next_label(dname, NULL); + const knot_dname_t *next_suffix = knot_wire_next_label(suffix, compr->wire); + + // Two labels match, extend suffix length. + if (!label_is_equal(dname, suffix)) { + // If they don't match, write unmatched labels. + uint16_t mismatch_len = (dname - match_begin) + (*dname + 1); + WRITE_LABEL(dst, written, match_begin, max, mismatch_len); + // Start new potential match. + match_begin = next_dname; + compr_ptr = next_suffix; + } + + // Jump to next labels. + dname = next_dname; + suffix = next_suffix; + } + + // If match begins at the end of the name, write '\0' label. + if (match_begin == dname) { + WRITE_LABEL(dst, written, dname, max, 1); + } else { + // Match covers >0 labels, write out compression pointer. + if (written + sizeof(uint16_t) > max) { + return KNOT_ESPACE; + } + knot_wire_put_pointer(dst + written, compr_ptr - compr->wire); + written += sizeof(uint16_t); + } + + assert(dst >= compr->wire); + size_t wire_pos = dst - compr->wire; + assert(wire_pos < KNOT_WIRE_MAX_PKTSIZE); + + // Heuristics - expect similar names are grouped together. + if (written > sizeof(uint16_t) && wire_pos + written < KNOT_WIRE_PTR_MAX) { + compr->suffix.pos = wire_pos; + compr->suffix.labels = orig_labels; + } + + return written; +} + +#define WRITE_OWNER_CHECK(size, dst_avail) \ + if ((size) > *(dst_avail)) { \ + return KNOT_ESPACE; \ + } + +#define WRITE_OWNER_INCR(dst, dst_avail, size) \ + *(dst) += (size); \ + *(dst_avail) -= (size); + +static int write_owner(const knot_rrset_t *rrset, uint8_t **dst, size_t *dst_avail, + knot_compr_t *compr) +{ + assert(rrset); + assert(dst && *dst); + assert(dst_avail); + + // Check for zero label owner (don't compress). + uint16_t owner_pointer = 0; + if (*rrset->owner != '\0') { + owner_pointer = compr_get_ptr(compr, KNOT_COMPR_HINT_OWNER); + } + + // Write result. + if (owner_pointer > 0) { + WRITE_OWNER_CHECK(sizeof(uint16_t), dst_avail); + knot_wire_put_pointer(*dst, owner_pointer); + WRITE_OWNER_INCR(dst, dst_avail, sizeof(uint16_t)); + // Check for coincidence with previous RR set. + } else if (compr != NULL && compr->suffix.pos != 0 && *rrset->owner != '\0' && + dname_equal_wire(rrset->owner, compr->wire + compr->suffix.pos, + compr->wire)) { + WRITE_OWNER_CHECK(sizeof(uint16_t), dst_avail); + knot_wire_put_pointer(*dst, compr->suffix.pos); + compr_set_ptr(compr, KNOT_COMPR_HINT_OWNER, + compr->wire + compr->suffix.pos, + knot_dname_size(rrset->owner)); + WRITE_OWNER_INCR(dst, dst_avail, sizeof(uint16_t)); + } else { + if (compr != NULL) { + compr->suffix.pos = KNOT_WIRE_HEADER_SIZE; + compr->suffix.labels = + knot_dname_labels(compr->wire + compr->suffix.pos, + compr->wire); + } + // WRITE_OWNER_CHECK not needed, compr_put_dname has a check. + int written = compr_put_dname(rrset->owner, *dst, + dname_max(*dst_avail), compr); + if (written < 0) { + return written; + } + + compr_set_ptr(compr, KNOT_COMPR_HINT_OWNER, *dst, written); + WRITE_OWNER_INCR(dst, dst_avail, written); + } + + return KNOT_EOK; +} + +static int write_fixed_header(const knot_rrset_t *rrset, uint16_t rrset_index, + uint8_t **dst, size_t *dst_avail, uint16_t flags) +{ + assert(rrset); + assert(rrset_index < rrset->rrs.count); + assert(dst && *dst); + assert(dst_avail); + + // Write header. + wire_ctx_t write = wire_ctx_init(*dst, *dst_avail); + + wire_ctx_write_u16(&write, rrset->type); + wire_ctx_write_u16(&write, rrset->rclass); + + if ((flags & KNOT_PF_ORIGTTL) && rrset->type == KNOT_RRTYPE_RRSIG) { + const knot_rdata_t *rdata = knot_rdataset_at(&rrset->rrs, rrset_index); + wire_ctx_write_u32(&write, knot_rrsig_original_ttl(rdata)); + } else if ((flags & KNOT_PF_SOAMINTTL) && rrset->type == KNOT_RRTYPE_SOA) { + const knot_rdata_t *rdata = knot_rdataset_at(&rrset->rrs, rrset_index); + wire_ctx_write_u32(&write, MIN(knot_soa_minimum(rdata), rrset->ttl)); + } else { + wire_ctx_write_u32(&write, rrset->ttl); + } + + // Check write. + if (write.error != KNOT_EOK) { + return write.error; + } + + // Update buffer. + *dst = write.position; + *dst_avail = wire_ctx_available(&write); + + return KNOT_EOK; +} + +static int compress_rdata_dname(const uint8_t **src, size_t *src_avail, + uint8_t **dst, size_t *dst_avail, + knot_compr_t *put_compr, knot_compr_t *compr, + uint16_t hint) +{ + assert(src && *src); + assert(src_avail); + assert(dst && *dst); + assert(dst_avail); + + // Source domain name. + const knot_dname_t *dname = *src; + size_t dname_size = knot_dname_size(dname); + + // Output domain name. + int written = compr_put_dname(dname, *dst, dname_max(*dst_avail), put_compr); + if (written < 0) { + return written; + } + + // Update compression hints. + if (compr_get_ptr(compr, hint) == 0) { + compr_set_ptr(compr, hint, *dst, written); + } + + // Update buffers. + *dst += written; + *dst_avail -= written; + + *src += dname_size; + *src_avail -= dname_size; + + return KNOT_EOK; +} + +static int rdata_traverse_write(const uint8_t **src, size_t *src_avail, + uint8_t **dst, size_t *dst_avail, + const knot_rdata_descriptor_t *desc, + knot_compr_t *compr, uint16_t hint) +{ + for (const int *type = desc->block_types; *type != KNOT_RDATA_WF_END; type++) { + int ret; + knot_compr_t *put_compr = NULL; + switch (*type) { + case KNOT_RDATA_WF_COMPRESSIBLE_DNAME: + put_compr = compr; + // FALLTHROUGH + case KNOT_RDATA_WF_DECOMPRESSIBLE_DNAME: + case KNOT_RDATA_WF_FIXED_DNAME: + ret = compress_rdata_dname(src, src_avail, dst, dst_avail, + put_compr, compr, hint); + break; + case KNOT_RDATA_WF_NAPTR_HEADER: + ret = write_rdata_naptr_header(src, src_avail, dst, dst_avail); + break; + case KNOT_RDATA_WF_REMAINDER: + ret = write_rdata_fixed(src, src_avail, dst, dst_avail, *src_avail); + break; + default: + // Fixed size block. + assert(*type > 0); + ret = write_rdata_fixed(src, src_avail, dst, dst_avail, *type); + break; + } + if (ret != KNOT_EOK) { + return ret; + } + } + + return KNOT_EOK; +} + +static int write_rdata(const knot_rrset_t *rrset, uint16_t rrset_index, + uint8_t **dst, size_t *dst_avail, knot_compr_t *compr) +{ + assert(rrset); + assert(rrset_index < rrset->rrs.count); + assert(dst && *dst); + assert(dst_avail); + + const knot_rdata_t *rdata = knot_rdataset_at(&rrset->rrs, rrset_index); + + // Reserve space for RDLENGTH. + if (sizeof(uint16_t) > *dst_avail) { + return KNOT_ESPACE; + } + + uint8_t *wire_rdlength = *dst; + *dst += sizeof(uint16_t); + *dst_avail -= sizeof(uint16_t); + uint8_t *wire_rdata_begin = *dst; + + // Write RDATA. + const uint8_t *src = rdata->data; + size_t src_avail = rdata->len; + if (src_avail > 0) { + // Only write non-empty data. + const knot_rdata_descriptor_t *desc = + knot_get_rdata_descriptor(rrset->type); + int ret = rdata_traverse_write(&src, &src_avail, dst, dst_avail, + desc, compr, KNOT_COMPR_HINT_RDATA + rrset_index); + if (ret != KNOT_EOK) { + return ret; + } + } + + // Check for trailing data in the message. + if (src_avail > 0) { + return KNOT_EMALF; + } + + // Write final RDLENGTH. + size_t rdlength = *dst - wire_rdata_begin; + knot_wire_write_u16(wire_rdlength, rdlength); + + return KNOT_EOK; +} + +static int write_rr(const knot_rrset_t *rrset, uint16_t rrset_index, uint8_t **dst, + size_t *dst_avail, knot_compr_t *compr, uint16_t flags) +{ + int ret = write_owner(rrset, dst, dst_avail, compr); + if (ret != KNOT_EOK) { + return ret; + } + + ret = write_fixed_header(rrset, rrset_index, dst, dst_avail, flags); + if (ret != KNOT_EOK) { + return ret; + } + + return write_rdata(rrset, rrset_index, dst, dst_avail, compr); +} + +_public_ +int knot_rrset_to_wire_extra(const knot_rrset_t *rrset, uint8_t *wire, + uint16_t max_size, uint16_t rotate, + knot_compr_t *compr, uint16_t flags) +{ + if (rrset == NULL || wire == NULL) { + return KNOT_EINVAL; + } + if (rrset->rrs.count == 0) { + return 0; + } + if (rotate != 0) { + rotate %= rrset->rrs.count; + } + + uint8_t *write = wire; + size_t capacity = max_size; + + uint16_t count = rrset->rrs.count; + for (int i = rotate; i < count + rotate; i++) { + uint16_t pos = (i < count) ? i : (i - count); + int ret = write_rr(rrset, pos, &write, &capacity, compr, flags); + if (ret != KNOT_EOK) { + return ret; + } + } + + return write - wire; +} + +static int parse_header(const uint8_t *wire, size_t *pos, size_t pkt_size, + knot_mm_t *mm, knot_rrset_t *rrset, uint16_t *rdlen) +{ + assert(wire); + assert(pos); + assert(rrset); + assert(rdlen); + + wire_ctx_t src = wire_ctx_init_const(wire, pkt_size); + wire_ctx_set_offset(&src, *pos); + + int compr_size = knot_dname_wire_check(src.position, wire + pkt_size, wire); + if (compr_size <= 0) { + return KNOT_EMALF; + } + + knot_dname_storage_t buff; + int decompr_size = knot_dname_unpack(buff, src.position, sizeof(buff), wire); + if (decompr_size <= 0) { + return KNOT_EMALF; + } + + knot_dname_t *owner = mm_alloc(mm, decompr_size); + if (owner == NULL) { + return KNOT_ENOMEM; + } + memcpy(owner, buff, decompr_size); + wire_ctx_skip(&src, compr_size); + + uint16_t type = wire_ctx_read_u16(&src); + uint16_t rclass = wire_ctx_read_u16(&src); + uint32_t ttl = wire_ctx_read_u32(&src); + *rdlen = wire_ctx_read_u16(&src); + + if (src.error != KNOT_EOK) { + knot_dname_free(owner, mm); + return KNOT_EMALF; + } + + if (wire_ctx_available(&src) < *rdlen) { + knot_dname_free(owner, mm); + return KNOT_EMALF; + } + + *pos = wire_ctx_offset(&src); + + knot_rrset_init(rrset, owner, type, rclass, ttl); + + return KNOT_EOK; +} + +static int decompress_rdata_dname(const uint8_t **src, size_t *src_avail, + uint8_t **dst, size_t *dst_avail, + const uint8_t *pkt_wire) +{ + assert(src && *src); + assert(src_avail); + assert(dst && *dst); + assert(dst_avail); + + int compr_size = knot_dname_wire_check(*src, *src + *src_avail, pkt_wire); + if (compr_size <= 0) { + return compr_size; + } + + int decompr_size = knot_dname_unpack(*dst, *src, *dst_avail, pkt_wire); + if (decompr_size <= 0) { + return decompr_size; + } + + // Update buffers. + *dst += decompr_size; + *dst_avail -= decompr_size; + + *src += compr_size; + *src_avail -= compr_size; + + return KNOT_EOK; +} + +static int rdata_traverse_parse(const uint8_t **src, size_t *src_avail, + uint8_t **dst, size_t *dst_avail, + const knot_rdata_descriptor_t *desc, + const uint8_t *pkt_wire) +{ + for (const int *type = desc->block_types; *type != KNOT_RDATA_WF_END; type++) { + int ret; + switch (*type) { + case KNOT_RDATA_WF_COMPRESSIBLE_DNAME: + case KNOT_RDATA_WF_DECOMPRESSIBLE_DNAME: + case KNOT_RDATA_WF_FIXED_DNAME: + ret = decompress_rdata_dname(src, src_avail, dst, dst_avail, + pkt_wire); + break; + case KNOT_RDATA_WF_NAPTR_HEADER: + ret = write_rdata_naptr_header(src, src_avail, dst, dst_avail); + break; + case KNOT_RDATA_WF_REMAINDER: + ret = write_rdata_fixed(src, src_avail, dst, dst_avail, *src_avail); + break; + default: + /* Fixed size block */ + assert(*type > 0); + ret = write_rdata_fixed(src, src_avail, dst, dst_avail, *type); + break; + } + if (ret != KNOT_EOK) { + return ret; + } + } + + return KNOT_EOK; +} + +static bool allow_zero_rdata(const knot_rrset_t *rr, + const knot_rdata_descriptor_t *desc) +{ + return rr->rclass != KNOT_CLASS_IN || // NONE and ANY for DDNS + rr->type == KNOT_RRTYPE_APL || // APL RR type + desc->type_name == NULL; // Unknown RR type +} + +static int parse_rdata(const uint8_t *pkt_wire, size_t *pos, size_t pkt_size, + knot_mm_t *mm, uint16_t rdlength, knot_rrset_t *rrset) +{ + assert(pkt_wire); + assert(pos); + assert(rrset); + + const knot_rdata_descriptor_t *desc = knot_get_rdata_descriptor(rrset->type); + if (desc->type_name == NULL) { + desc = knot_get_obsolete_rdata_descriptor(rrset->type); + } + + if (rdlength == 0) { + if (allow_zero_rdata(rrset, desc)) { + return knot_rrset_add_rdata(rrset, NULL, 0, mm); + } else { + return KNOT_EMALF; + } + } else if (pkt_size - *pos < rdlength) { + return KNOT_EMALF; + } + + // Buffer for parsed rdata (decompression extends rdata length). + const size_t max_rdata_len = UINT16_MAX; + uint8_t buf[knot_rdata_size(max_rdata_len)]; + knot_rdata_t *rdata = (knot_rdata_t *)buf; + + const uint8_t *src = pkt_wire + *pos; + size_t src_avail = rdlength; + uint8_t *dst = rdata->data; + size_t dst_avail = max_rdata_len; + + // Parse RDATA. + int ret = rdata_traverse_parse(&src, &src_avail, &dst, &dst_avail, desc, pkt_wire); + if (ret != KNOT_EOK) { + return KNOT_EMALF; + } + + // Check for trailing data. + size_t real_len = max_rdata_len - dst_avail; + if (real_len < rdlength) { + return KNOT_EMALF; + } + rdata->len = real_len; + + ret = knot_rdataset_add(&rrset->rrs, rdata, mm); + if (ret != KNOT_EOK) { + return ret; + } + + // Update position pointer. + *pos += rdlength; + + return KNOT_EOK; +} + +_public_ +int knot_rrset_rr_from_wire(const uint8_t *wire, size_t *pos, size_t max_size, + knot_rrset_t *rrset, knot_mm_t *mm, bool canonical) +{ + if (wire == NULL || pos == NULL || *pos > max_size || rrset == NULL) { + return KNOT_EINVAL; + } + + uint16_t rdlen = 0; + int ret = parse_header(wire, pos, max_size, mm, rrset, &rdlen); + if (ret != KNOT_EOK) { + return ret; + } + + ret = parse_rdata(wire, pos, max_size, mm, rdlen, rrset); + if (ret != KNOT_EOK) { + knot_rrset_clear(rrset, mm); + return ret; + } + + // Convert RR to the canonical format. + if (canonical) { + ret = knot_rrset_rr_to_canonical(rrset); + if (ret != KNOT_EOK) { + knot_rrset_clear(rrset, mm); + } + } + + return KNOT_EOK; +} |