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-rw-r--r--src/libknot/rrtype/opt.c687
1 files changed, 687 insertions, 0 deletions
diff --git a/src/libknot/rrtype/opt.c b/src/libknot/rrtype/opt.c
new file mode 100644
index 0000000..294689c
--- /dev/null
+++ b/src/libknot/rrtype/opt.c
@@ -0,0 +1,687 @@
+/* Copyright (C) 2022 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 <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+#include <netinet/in.h>
+#include <sys/socket.h>
+
+#include "libknot/attribute.h"
+#include "libknot/consts.h"
+#include "libknot/descriptor.h"
+#include "libknot/lookup.h"
+#include "libknot/packet/pkt.h"
+#include "libknot/rrtype/opt.h"
+#include "contrib/mempattern.h"
+#include "contrib/wire_ctx.h"
+
+/*! \brief Some implementation-related constants. */
+enum {
+ /*! \brief Byte offset of the extended RCODE field in TTL. */
+ EDNS_OFFSET_RCODE = 0,
+ /*! \brief Byte offset of the version field in TTL. */
+ EDNS_OFFSET_VERSION = 1,
+
+ /*! \brief Byte offset of the family field in option data. */
+ EDNS_OFFSET_CLIENT_SUBNET_FAMILY = 0,
+ /*! \brief Byte offset of the source mask field in option data. */
+ EDNS_OFFSET_CLIENT_SUBNET_SRC_MASK = 2,
+ /*! \brief Byte offset of the destination mask field in option data. */
+ EDNS_OFFSET_CLIENT_SUBNET_DST_MASK = 3,
+ /*! \brief Byte offset of the address field in option data. */
+ EDNS_OFFSET_CLIENT_SUBNET_ADDR = 4,
+};
+
+_public_
+int knot_edns_init(knot_rrset_t *opt_rr, uint16_t max_pld,
+ uint8_t ext_rcode, uint8_t ver, knot_mm_t *mm)
+{
+ if (opt_rr == NULL) {
+ return KNOT_EINVAL;
+ }
+
+ /* Initialize RRSet. */
+ knot_dname_t *owner = knot_dname_copy((const uint8_t *)"", mm);
+ if (owner == NULL) {
+ return KNOT_ENOMEM;
+ }
+
+ knot_rrset_init(opt_rr, owner, KNOT_RRTYPE_OPT, max_pld, 0);
+
+ /* Create empty RDATA */
+ int ret = knot_rrset_add_rdata(opt_rr, NULL, 0, mm);
+ if (ret == KNOT_EOK) {
+ knot_edns_set_ext_rcode(opt_rr, ext_rcode);
+ knot_edns_set_version(opt_rr, ver);
+ }
+
+ return ret;
+}
+
+_public_
+uint8_t knot_edns_get_ext_rcode(const knot_rrset_t *opt_rr)
+{
+ assert(opt_rr != NULL);
+ uint32_t ttl = 0;
+ wire_ctx_t w = wire_ctx_init((uint8_t *)&ttl, sizeof(ttl));
+ // TTL is stored in machine byte order. Convert it to wire order first.
+ wire_ctx_write_u32(&w, opt_rr->ttl);
+ wire_ctx_set_offset(&w, EDNS_OFFSET_RCODE);
+ return wire_ctx_read_u8(&w);
+}
+
+static void set_value_to_ttl(knot_rrset_t *opt_rr, size_t offset, uint8_t value)
+{
+ uint32_t ttl = 0;
+ wire_ctx_t w = wire_ctx_init((uint8_t *)&ttl, sizeof(ttl));
+ // TTL is stored in machine byte order. Convert it to wire order first.
+ wire_ctx_write_u32(&w, opt_rr->ttl);
+ // Set the Extended RCODE in the converted TTL
+ wire_ctx_set_offset(&w, offset);
+ wire_ctx_write_u8(&w, value);
+ // Convert it back to machine byte order
+ wire_ctx_set_offset(&w, 0);
+ uint32_t ttl_local = wire_ctx_read_u32(&w);
+ // Store the TTL to the RDATA
+ opt_rr->ttl = ttl_local;
+}
+
+_public_
+void knot_edns_set_ext_rcode(knot_rrset_t *opt_rr, uint8_t ext_rcode)
+{
+ assert(opt_rr != NULL);
+ set_value_to_ttl(opt_rr, EDNS_OFFSET_RCODE, ext_rcode);
+}
+
+_public_
+uint8_t knot_edns_get_version(const knot_rrset_t *opt_rr)
+{
+ assert(opt_rr != NULL);
+ uint32_t ttl = 0;
+ wire_ctx_t w = wire_ctx_init((uint8_t *)&ttl, sizeof(ttl));
+ // TTL is stored in machine byte order. Convert it to wire order first.
+ wire_ctx_write_u32(&w, opt_rr->ttl);
+ wire_ctx_set_offset(&w, EDNS_OFFSET_VERSION);
+ return wire_ctx_read_u8(&w);
+}
+
+_public_
+void knot_edns_set_version(knot_rrset_t *opt_rr, uint8_t version)
+{
+ assert(opt_rr != NULL);
+ set_value_to_ttl(opt_rr, EDNS_OFFSET_VERSION, version);
+}
+
+/*!
+ * \brief Add new EDNS option by replacing RDATA of OPT RR.
+ *
+ * \param opt OPT RR structure to add the Option to.
+ * \param code Option code.
+ * \param size Option data length in bytes.
+ * \param mm Memory context.
+ *
+ * \return Pointer to uninitialized option data.
+ */
+static uint8_t *edns_add(knot_rrset_t *opt, uint16_t code, uint16_t size,
+ knot_mm_t *mm)
+{
+ assert(opt->rrs.count == 1);
+
+ // extract old RDATA
+
+ uint8_t *old_data = opt->rrs.rdata->data;
+ uint16_t old_data_len = opt->rrs.rdata->len;
+
+ // construct new RDATA
+
+ uint16_t new_data_len = old_data_len + KNOT_EDNS_OPTION_HDRLEN + size;
+ uint8_t new_data[new_data_len];
+
+ wire_ctx_t wire = wire_ctx_init(new_data, new_data_len);
+ wire_ctx_write(&wire, old_data, old_data_len);
+ wire_ctx_write_u16(&wire, code);
+ wire_ctx_write_u16(&wire, size);
+
+ // prepare EDNS option data
+
+ size_t offset = wire_ctx_offset(&wire);
+ wire_ctx_clear(&wire, size);
+
+ assert(wire_ctx_available(&wire) == 0);
+ assert(wire.error == KNOT_EOK);
+
+ // replace RDATA
+
+ knot_rdataset_clear(&opt->rrs, mm);
+ if (knot_rrset_add_rdata(opt, new_data, new_data_len, mm) != KNOT_EOK) {
+ return NULL;
+ }
+
+ return opt->rrs.rdata->data + offset;
+}
+
+_public_
+int knot_edns_reserve_option(knot_rrset_t *opt_rr, uint16_t code,
+ uint16_t size, uint8_t **wire_ptr, knot_mm_t *mm)
+{
+ if (!opt_rr) {
+ return KNOT_EINVAL;
+ }
+
+ uint8_t *wire = edns_add(opt_rr, code, size, mm);
+ if (!wire) {
+ return KNOT_ENOMEM;
+ }
+
+ if (wire_ptr) {
+ *wire_ptr = wire;
+ }
+
+ return KNOT_EOK;
+}
+
+_public_
+int knot_edns_add_option(knot_rrset_t *opt_rr, uint16_t code,
+ uint16_t size, const uint8_t *data, knot_mm_t *mm)
+{
+ if (!opt_rr || (size > 0 && !data)) {
+ return KNOT_EINVAL;
+ }
+
+ uint8_t *wire = edns_add(opt_rr, code, size, mm);
+ if (!wire) {
+ return KNOT_ENOMEM;
+ }
+
+ if (size > 0) {
+ memcpy(wire, data, size);
+ }
+
+ return KNOT_EOK;
+}
+
+_public_
+uint8_t *knot_edns_get_option(const knot_rrset_t *opt_rr, uint16_t code,
+ const uint8_t *previous)
+{
+ if (opt_rr == NULL) {
+ return NULL;
+ }
+
+ knot_rdata_t *rdata = opt_rr->rrs.rdata;
+ if (rdata == NULL || rdata->len == 0) {
+ return NULL;
+ }
+
+ wire_ctx_t wire = wire_ctx_init_const(rdata->data, rdata->len);
+ if (previous != NULL) {
+ if (previous < wire.wire) {
+ return NULL;
+ }
+ wire_ctx_set_offset(&wire, previous - wire.wire + 2);
+ uint16_t opt_len = wire_ctx_read_u16(&wire);
+ wire_ctx_skip(&wire, opt_len);
+ }
+
+ while (wire_ctx_available(&wire) > 0 && wire.error == KNOT_EOK) {
+ uint8_t *pos = wire.position;
+ uint16_t opt_code = wire_ctx_read_u16(&wire);
+ uint16_t opt_len = wire_ctx_read_u16(&wire);
+ wire_ctx_skip(&wire, opt_len);
+ if (wire.error == KNOT_EOK && opt_code == code) {
+ return pos;
+ }
+ }
+
+ return NULL;
+}
+
+_public_
+int knot_edns_get_options(knot_rrset_t *opt_rr, knot_edns_options_t **out,
+ knot_mm_t *mm)
+{
+ if (opt_rr == NULL || opt_rr->rrs.count > 1 || out == NULL) {
+ return KNOT_EINVAL;
+ }
+
+ knot_rdata_t *rdata = opt_rr->rrs.rdata;
+ if (rdata == NULL || rdata->len == 0) {
+ return KNOT_EOK;
+ }
+
+ knot_edns_options_t *options = mm_calloc(mm, 1, sizeof(*options));
+
+ wire_ctx_t wire = wire_ctx_init_const(rdata->data, rdata->len);
+
+ while (wire_ctx_available(&wire) > 0 && wire.error == KNOT_EOK) {
+ uint8_t *pos = wire.position;
+ uint16_t opt_code = wire_ctx_read_u16(&wire);
+ uint16_t opt_len = wire_ctx_read_u16(&wire);
+ wire_ctx_skip(&wire, opt_len);
+ if (wire.error == KNOT_EOK && opt_code <= KNOT_EDNS_MAX_OPTION_CODE) {
+ options->ptr[opt_code] = pos;
+ }
+ }
+
+ if (wire.error != KNOT_EOK) {
+ mm_free(mm, options);
+ return wire.error;
+ }
+
+ *out = options;
+ return KNOT_EOK;
+}
+
+_public_
+int knot_edns_alignment_size(size_t current_pkt_size,
+ size_t current_opt_size,
+ size_t block_size)
+{
+ if (current_opt_size == 0 || block_size == 0) {
+ return -1;
+ }
+
+ size_t current_size = current_pkt_size + current_opt_size;
+ if (current_size % block_size == 0) {
+ return -1;
+ }
+
+ size_t modulo = (current_size + KNOT_EDNS_OPTION_HDRLEN) % block_size;
+
+ return (modulo == 0) ? 0 : block_size - modulo;
+}
+
+/*!
+ * \brief EDNS Client Subnet family data.
+ */
+typedef struct {
+ int platform; //!< Platform family identifier.
+ uint16_t iana; //!< IANA family identifier.
+ size_t offset; //!< Socket address offset.
+ size_t size; //!< Socket address size.
+} ecs_family_t;
+
+#define ECS_INIT(platform, iana, type, member) \
+ { platform, iana, offsetof(type, member), sizeof(((type *)0)->member) }
+
+/*!
+ * \brief Supported EDNS Client Subnet families.
+ *
+ * https://www.iana.org/assignments/address-family-numbers/address-family-numbers.xml
+ */
+static const ecs_family_t ECS_FAMILIES[] = {
+ ECS_INIT(AF_INET, KNOT_ADDR_FAMILY_IPV4, struct sockaddr_in, sin_addr),
+ ECS_INIT(AF_INET6, KNOT_ADDR_FAMILY_IPV6, struct sockaddr_in6, sin6_addr),
+ { 0 }
+};
+
+/*!
+ * \brief Lookup ECS family by platform identifier.
+ */
+static const ecs_family_t *ecs_family_by_platform(int family)
+{
+ for (const ecs_family_t *f = ECS_FAMILIES; f->size > 0; f++) {
+ if (f->platform == family) {
+ return f;
+ }
+ }
+
+ return NULL;
+}
+
+/*!
+ * \brief Lookup ECS family by IANA identifier.
+ */
+static const ecs_family_t *ecs_family_by_iana(uint16_t family)
+{
+ for (const ecs_family_t *f = ECS_FAMILIES; f->size > 0; f++) {
+ if (f->iana == family) {
+ return f;
+ }
+ }
+
+ return NULL;
+}
+
+/*!
+ * \brief Get ECS address prefix size in bytes.
+ */
+static uint16_t ecs_prefix_size(uint8_t prefix)
+{
+ return (prefix + 7) / 8;
+}
+
+static uint8_t ecs_prefix_lsb_mask(uint8_t prefix)
+{
+ int modulo = prefix % 8;
+ if (modulo == 0) {
+ return 0xff;
+ } else {
+ return 0xff << (8 - modulo);
+ }
+}
+
+/*!
+ * \brief Write raw network address prefix and clear the rest of the buffer.
+ */
+static void ecs_write_address(wire_ctx_t *dst, wire_ctx_t *src, int8_t prefix)
+{
+ size_t count = ecs_prefix_size(prefix);
+ uint8_t lsb_mask = ecs_prefix_lsb_mask(prefix);
+
+ if (count > 0) {
+ wire_ctx_copy(dst, src, count);
+ if (dst->error != KNOT_EOK) {
+ return;
+ }
+ dst->position[-1] &= lsb_mask;
+ }
+
+ size_t blank = wire_ctx_available(dst);
+ wire_ctx_clear(dst, blank);
+}
+
+/*!
+ * \brief Check if ECS parameters are valid.
+ */
+static bool ecs_is_valid(const knot_edns_client_subnet_t *ecs)
+{
+ if (ecs == NULL) {
+ return false;
+ }
+
+ const ecs_family_t *f = ecs_family_by_iana(ecs->family);
+
+ return f != NULL && // known family check
+ (ecs->source_len <= f->size * 8) && // family address maximum check
+ (ecs->scope_len <= f->size * 8); // family address maximum check
+}
+
+_public_
+uint16_t knot_edns_client_subnet_size(const knot_edns_client_subnet_t *ecs)
+{
+ if (!ecs_is_valid(ecs)) {
+ return 0;
+ }
+
+ return sizeof(ecs->family) +
+ sizeof(ecs->source_len) +
+ sizeof(ecs->scope_len) +
+ ecs_prefix_size(ecs->source_len);
+}
+
+_public_
+int knot_edns_client_subnet_write(uint8_t *option, uint16_t option_len,
+ const knot_edns_client_subnet_t *ecs)
+{
+ if (option == NULL || ecs == NULL) {
+ return KNOT_EINVAL;
+ }
+
+ if (!ecs_is_valid(ecs)) {
+ return KNOT_EINVAL;
+ }
+
+ wire_ctx_t wire = wire_ctx_init(option, option_len);
+ wire_ctx_t addr = wire_ctx_init_const(ecs->address, sizeof(ecs->address));
+
+ wire_ctx_write_u16(&wire, ecs->family);
+ wire_ctx_write_u8(&wire, ecs->source_len);
+ wire_ctx_write_u8(&wire, ecs->scope_len);
+ ecs_write_address(&wire, &addr, ecs->source_len);
+
+ if (wire.error != KNOT_EOK) {
+ return wire.error;
+ }
+
+ return KNOT_EOK;
+}
+
+_public_
+int knot_edns_client_subnet_parse(knot_edns_client_subnet_t *ecs,
+ const uint8_t *option, uint16_t option_len)
+{
+ if (ecs == NULL || option == NULL) {
+ return KNOT_EINVAL;
+ }
+
+ knot_edns_client_subnet_t result = { 0 };
+
+ wire_ctx_t wire = wire_ctx_init_const(option, option_len);
+ wire_ctx_t addr = wire_ctx_init(result.address, sizeof(result.address));
+
+ result.family = wire_ctx_read_u16(&wire);
+ result.source_len = wire_ctx_read_u8(&wire);
+ result.scope_len = wire_ctx_read_u8(&wire);
+ ecs_write_address(&addr, &wire, result.source_len);
+
+ if (addr.error != KNOT_EOK || wire.error != KNOT_EOK) {
+ return KNOT_EMALF;
+ }
+
+ if (!ecs_is_valid(&result)) {
+ return KNOT_EMALF;
+ }
+
+ *ecs = result;
+ return KNOT_EOK;
+}
+
+_public_
+int knot_edns_client_subnet_set_addr(knot_edns_client_subnet_t *ecs,
+ const struct sockaddr_storage *addr)
+{
+ if (ecs == NULL || addr == NULL) {
+ return KNOT_EINVAL;
+ }
+
+ const ecs_family_t *f = ecs_family_by_platform(addr->ss_family);
+ if (f == NULL) {
+ return KNOT_ENOTSUP;
+ }
+
+ ecs->family = f->iana;
+ ecs->source_len = f->size * 8;
+ ecs->scope_len = 0;
+
+ wire_ctx_t dst = wire_ctx_init(ecs->address, sizeof(ecs->address));
+ wire_ctx_t src = wire_ctx_init_const((uint8_t *)addr + f->offset, f->size);
+ ecs_write_address(&dst, &src, ecs->source_len);
+
+ assert(dst.error == KNOT_EOK);
+
+ return KNOT_EOK;
+}
+
+_public_
+int knot_edns_client_subnet_get_addr(struct sockaddr_storage *addr,
+ const knot_edns_client_subnet_t *ecs)
+{
+ if (addr == NULL || ecs == NULL) {
+ return KNOT_EINVAL;
+ }
+
+ const ecs_family_t *f = ecs_family_by_iana(ecs->family);
+ if (f == NULL) {
+ return KNOT_ENOTSUP;
+ }
+
+ addr->ss_family = f->platform;
+
+ wire_ctx_t dst = wire_ctx_init((uint8_t *)addr + f->offset, f->size);
+ wire_ctx_t src = wire_ctx_init_const(ecs->address, sizeof(ecs->address));
+ ecs_write_address(&dst, &src, ecs->source_len);
+
+ assert(dst.error == KNOT_EOK);
+
+ return KNOT_EOK;
+}
+
+_public_
+uint16_t knot_edns_keepalive_size(uint16_t timeout)
+{
+ return (timeout > 0) ? sizeof(uint16_t) : 0;
+}
+
+_public_
+int knot_edns_keepalive_write(uint8_t *option, uint16_t option_len, uint16_t timeout)
+{
+ if (option == NULL) {
+ return KNOT_EINVAL;
+ }
+
+ if (timeout == 0) {
+ return KNOT_EOK;
+ }
+
+ wire_ctx_t wire = wire_ctx_init(option, option_len);
+ wire_ctx_write_u16(&wire, timeout);
+
+ return wire.error;
+}
+
+_public_
+int knot_edns_keepalive_parse(uint16_t *timeout, const uint8_t *option,
+ uint16_t option_len)
+{
+ if (timeout == NULL || option == NULL) {
+ return KNOT_EINVAL;
+ }
+
+ *timeout = 0;
+
+ if (option_len > 0) {
+ wire_ctx_t wire = wire_ctx_init_const(option, option_len);
+ *timeout = wire_ctx_read_u16(&wire);
+
+ if (wire.error != KNOT_EOK) {
+ return KNOT_EMALF;
+ }
+ }
+
+ return KNOT_EOK;
+}
+
+_public_
+uint16_t knot_edns_chain_size(const knot_dname_t *point)
+{
+ return knot_dname_size(point);
+}
+
+_public_
+int knot_edns_chain_write(uint8_t *option, uint16_t option_len,
+ const knot_dname_t *point)
+{
+ if (option == NULL || point == NULL) {
+ return KNOT_EINVAL;
+ }
+
+ wire_ctx_t wire = wire_ctx_init(option, option_len);
+ wire_ctx_write(&wire, point, knot_dname_size(point));
+
+ return wire.error;
+}
+
+_public_
+int knot_edns_chain_parse(knot_dname_t **point, const uint8_t *option,
+ uint16_t option_len, knot_mm_t *mm)
+{
+ if (point == NULL || option == NULL) {
+ return KNOT_EINVAL;
+ }
+
+ int ret = knot_dname_wire_check(option, option + option_len, NULL);
+ if (ret <= 0) {
+ return KNOT_EMALF;
+ }
+
+ *point = knot_dname_copy(option, mm);
+ if (*point == NULL) {
+ return KNOT_ENOMEM;
+ }
+
+ return KNOT_EOK;
+}
+
+_public_
+uint16_t knot_edns_cookie_size(const knot_edns_cookie_t *cc,
+ const knot_edns_cookie_t *sc)
+{
+ if (cc == NULL || cc->len != KNOT_EDNS_COOKIE_CLNT_SIZE) {
+ return 0;
+ } else if (sc == NULL || sc->len == 0) {
+ return KNOT_EDNS_COOKIE_CLNT_SIZE;
+ } else if (sc->len < KNOT_EDNS_COOKIE_SRVR_MIN_SIZE ||
+ sc->len > KNOT_EDNS_COOKIE_SRVR_MAX_SIZE) {
+ return 0;
+ } else {
+ return cc->len + sc->len;
+ }
+}
+
+_public_
+int knot_edns_cookie_write(uint8_t *option, uint16_t option_len,
+ const knot_edns_cookie_t *cc,
+ const knot_edns_cookie_t *sc)
+{
+ if (option == NULL || cc == NULL || cc->len != KNOT_EDNS_COOKIE_CLNT_SIZE) {
+ return KNOT_EINVAL;
+ }
+
+ wire_ctx_t wire = wire_ctx_init(option, option_len);
+ wire_ctx_write(&wire, cc->data, cc->len);
+
+ if (sc != NULL && sc->len > 0) {
+ if (sc->len < KNOT_EDNS_COOKIE_SRVR_MIN_SIZE ||
+ sc->len > KNOT_EDNS_COOKIE_SRVR_MAX_SIZE) {
+ return KNOT_EINVAL;
+ }
+ wire_ctx_write(&wire, sc->data, sc->len);
+ }
+
+ return wire.error;
+}
+
+_public_
+int knot_edns_cookie_parse(knot_edns_cookie_t *cc, knot_edns_cookie_t *sc,
+ const uint8_t *option, uint16_t option_len)
+{
+ if (cc == NULL || sc == NULL || option == NULL) {
+ return KNOT_EINVAL;
+ }
+
+ if (option_len != KNOT_EDNS_COOKIE_CLNT_SIZE &&
+ (option_len < KNOT_EDNS_COOKIE_CLNT_SIZE + KNOT_EDNS_COOKIE_SRVR_MIN_SIZE ||
+ option_len > KNOT_EDNS_COOKIE_CLNT_SIZE + KNOT_EDNS_COOKIE_SRVR_MAX_SIZE)) {
+ return KNOT_EMALF;
+ }
+ assert(option_len >= KNOT_EDNS_COOKIE_CLNT_SIZE);
+
+ memcpy(cc->data, option, KNOT_EDNS_COOKIE_CLNT_SIZE);
+ cc->len = KNOT_EDNS_COOKIE_CLNT_SIZE;
+
+ size_t sc_len = option_len - KNOT_EDNS_COOKIE_CLNT_SIZE;
+ if (sc_len == 0) {
+ sc->len = 0;
+ } else {
+ memcpy(sc->data, option + KNOT_EDNS_COOKIE_CLNT_SIZE, sc_len);
+ sc->len = sc_len;
+ }
+
+ return KNOT_EOK;
+}
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