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Diffstat (limited to '')
| -rw-r--r-- | lib/utils.h | 619 |
1 files changed, 619 insertions, 0 deletions
diff --git a/lib/utils.h b/lib/utils.h new file mode 100644 index 0000000..fab13fe --- /dev/null +++ b/lib/utils.h @@ -0,0 +1,619 @@ +/* Copyright (C) CZ.NIC, z.s.p.o. <knot-resolver@labs.nic.cz> + * SPDX-License-Identifier: GPL-3.0-or-later + */ + +#pragma once + +#include <dirent.h> +#include <stdio.h> +#include <stdlib.h> +#include <stdbool.h> +#include <sys/socket.h> +#include <sys/time.h> +#include <sys/un.h> +#include <netinet/in.h> +#include <unistd.h> + +#include <gnutls/gnutls.h> +#include <gnutls/crypto.h> + +#include <libknot/libknot.h> +#include <libknot/packet/pkt.h> +#include <libknot/rrset.h> +#include <libknot/rrtype/rrsig.h> +#include <uv.h> + +#include "kresconfig.h" +#include "contrib/mempattern.h" +#include "lib/defines.h" +#include "lib/generic/array.h" +#include "lib/log.h" + +/** When knot_pkt is passed from cache without ->wire, this is the ->size. */ +static const size_t KR_PKT_SIZE_NOWIRE = -1; + +/** Maximum length (excluding null-terminator) of a presentation-form address + * returned by `kr_straddr`. */ +#define KR_STRADDR_MAXLEN 109 + +/** Used for reserving enough space for the `kr_sockaddr_key` function + * output. */ +struct kr_sockaddr_key_storage { + char bytes[sizeof(struct sockaddr_storage)]; +}; + + +/* + * Logging and debugging. + */ + +/** @brief Callback for request events. */ +typedef void (*trace_callback_f)(struct kr_request *request); +/** + * @brief Callback for request logging handler. + * @param[in] msg Log message. Pointer is not valid after handler returns. */ +typedef void (*trace_log_f)(const struct kr_request *request, const char *msg); + +/** Assert() but always, regardless of -DNDEBUG. See also kr_assert(). */ +#define kr_require(expression) do { if (!(expression)) { \ + kr_fail(true, #expression, __func__, __FILE__, __LINE__); \ + __builtin_unreachable(); /* aid code analysis */ \ + } } while (false) + +/** Check an assertion that's recoverable. Return the true if it fails and needs handling. + * + * If the check fails, optionally fork()+abort() to generate coredump + * and continue running in parent process. Return value must be handled to + * ensure safe recovery from error. Use kr_require() for unrecoverable checks. + * The errno variable is not mangled, e.g. you can: if (kr_fails_assert(...)) return errno; + */ +#define kr_fails_assert(expression) !kr_assert_func((expression), #expression, \ + __func__, __FILE__, __LINE__) + +/** Kresd assertion without a return value. + * + * These can be turned on or off, for mandatory unrecoverable checks, use kr_require(). + * For recoverable checks, use kr_fails_assert(). + * */ +#define kr_assert(expression) (void)!kr_fails_assert((expression)) + +/** Whether kr_assert() and kr_fails_assert() checks should abort. */ +KR_EXPORT extern bool kr_dbg_assertion_abort; + +/** How often kr_assert() should fork the process before issuing abort (if configured). + * + * This can be useful for debugging rare edge-cases in production. + * if (kr_debug_assertion_abort && kr_debug_assertion_fork), it is + * possible to both obtain a coredump (from forked child) and recover from the + * non-fatal error in the parent process. + * + * == 0 (false): no forking + * > 0: minimum delay between forks + * (in milliseconds, each instance separately, randomized +-25%) + * < 0: no rate-limiting (not recommended) + */ +KR_EXPORT extern int kr_dbg_assertion_fork; + +/** Use kr_require(), kr_assert() or kr_fails_assert() instead of directly this function. */ +KR_EXPORT KR_COLD void kr_fail(bool is_fatal, const char* expr, const char *func, + const char *file, int line); + +/** Use kr_require(), kr_assert() or kr_fails_assert() instead of directly this function. */ +__attribute__ ((warn_unused_result)) +static inline bool kr_assert_func(bool result, const char *expr, const char *func, + const char *file, int line) +{ + if (!result) + kr_fail(false, expr, func, file, line); + return result; +} + +#define KR_DNAME_GET_STR(dname_str, dname) \ + char dname_str[KR_DNAME_STR_MAXLEN]; \ + knot_dname_to_str(dname_str, (dname), sizeof(dname_str)); \ + dname_str[sizeof(dname_str) - 1] = 0; + +#define KR_RRTYPE_GET_STR(rrtype_str, rrtype) \ + char rrtype_str[KR_RRTYPE_STR_MAXLEN]; \ + knot_rrtype_to_string((rrtype), rrtype_str, sizeof(rrtype_str)); \ + rrtype_str[sizeof(rrtype_str) - 1] = 0; + +// Use this for allocations with mm. +// Use mm_alloc for allocations into mempool + +/** A strcmp() variant directly usable for qsort() on an array of strings. */ +static inline int strcmp_p(const void *p1, const void *p2) +{ + return strcmp(*(char * const *)p1, *(char * const *)p2); +} + +/** Get current working directory with fallback value. */ +static inline void get_workdir(char *out, size_t len) { + if(getcwd(out, len) == NULL) { + static const char errprefix[] = "<invalid working directory>"; + strncpy(out, errprefix, len); + } +} + +/** @cond internal Array types */ +struct kr_context; + +struct ranked_rr_array_entry { + uint32_t qry_uid; + uint8_t rank; /**< enum kr_rank */ + uint8_t revalidation_cnt; + bool cached : 1; /**< Set to true if the entry was written into cache */ + bool yielded : 1; + bool to_wire : 1; /**< whether to be put into the answer */ + bool expiring : 1; /**< low remaining TTL; see is_expiring; only used in cache ATM */ + bool in_progress : 1; /**< build of RRset in progress, i.e. different format of RR data */ + bool dont_cache : 1; /**< avoid caching; useful e.g. for generated data */ + knot_rrset_t *rr; +}; +typedef struct ranked_rr_array_entry ranked_rr_array_entry_t; + +/** Array of RRsets coming from multiple queries; for struct kr_request. + * + * Notes: + * - RRSIGs are only considered to form an RRset when the types covered match; + * cache-related code relies on that! + * - RRsets from the same packet (qry_uid) get merged. + */ +typedef array_t(ranked_rr_array_entry_t *) ranked_rr_array_t; +/* @endcond */ + +typedef struct kr_http_header_array_entry { + char* name; + char* value; +} kr_http_header_array_entry_t; + +/** Array of HTTP headers for DoH. */ +typedef array_t(kr_http_header_array_entry_t) kr_http_header_array_t; + +/** Concatenate N strings. */ +KR_EXPORT +char* kr_strcatdup(unsigned n, ...); + +/** Construct absolute file path, without resolving symlinks. + * \return malloc-ed string or NULL (+errno in that case) */ +KR_EXPORT +char * kr_absolutize_path(const char *dirname, const char *fname); + +/** You probably want kr_rand_* convenience functions instead. + * This is a buffered version of gnutls_rnd(GNUTLS_RND_NONCE, ..) */ +KR_EXPORT +void kr_rnd_buffered(void *data, unsigned int size); + +/** Return a few random bytes. */ +KR_EXPORT inline +uint64_t kr_rand_bytes(unsigned int size) +{ + uint64_t result; + if (size <= 0 || size > sizeof(result)) { + kr_log_error(SYSTEM, "kr_rand_bytes(): EINVAL\n"); + abort(); + } + uint8_t data[sizeof(result)]; + kr_rnd_buffered(data, size); + /* I would have liked to dump the random data into a size_t directly, + * but that would work well only on little-endian machines, + * so instead I hope that the compiler will optimize this out. + * (Tested via reading assembly from usual gcc -O2 setup.) + * Alternatively we could waste more rnd bytes, but that seemed worse. */ + result = 0; + for (unsigned int i = 0; i < size; ++ i) { + result |= ((uint64_t)data[i]) << (i * 8); + } + return result; +} + +/** Throw a pseudo-random coin, succeeding approximately with probability nomin/denomin. + * - low precision, only one byte of randomness (or none with extreme parameters) + * - tip: use !kr_rand_coin() to get the complementary probability + */ +static inline bool kr_rand_coin(unsigned int nomin, unsigned int denomin) +{ + /* This function might be called with non-constant values + * so we try to handle odd corner cases instead of crash. */ + if (nomin >= denomin) + return true; + else if (nomin <= 0) + return false; + + /* threshold = how many parts from 256 are a success */ + unsigned int threshold = (nomin * 256 + /*rounding*/ denomin / 2) / denomin; + if (threshold == 0) threshold = 1; + if (threshold == 256) threshold = 255; + return (kr_rand_bytes(1) < threshold); +} + +/** Memory reservation routine for knot_mm_t */ +KR_EXPORT +int kr_memreserve(void *baton, void **mem, size_t elm_size, size_t want, size_t *have); + +/** @internal Fast packet reset. */ +KR_EXPORT +int kr_pkt_recycle(knot_pkt_t *pkt); + +/** @internal Clear packet payload. */ +KR_EXPORT +int kr_pkt_clear_payload(knot_pkt_t *pkt); + +/** Construct and put record to packet. */ +KR_EXPORT +int kr_pkt_put(knot_pkt_t *pkt, const knot_dname_t *name, uint32_t ttl, + uint16_t rclass, uint16_t rtype, const uint8_t *rdata, uint16_t rdlen); + +/** Set packet header suitable for authoritative answer. (for policy module) */ +KR_EXPORT +void kr_pkt_make_auth_header(knot_pkt_t *pkt); + +/** Get pointer to the in-header QNAME. + * + * That's normally not lower-cased. However, when receiving packets from upstream + * we xor-apply the secret during packet-parsing, so it would get lower-cased + * after that point if the case was right. + */ +static inline knot_dname_t * kr_pkt_qname_raw(const knot_pkt_t *pkt) +{ + if (pkt == NULL || pkt->qname_size == 0) { + return NULL; + } + return pkt->wire + KNOT_WIRE_HEADER_SIZE; +} + +/** Simple storage for IPx address and their ports or AF_UNSPEC. */ +union kr_sockaddr { + struct sockaddr ip; + struct sockaddr_in ip4; + struct sockaddr_in6 ip6; +}; + +/** Simple storage for IPx addresses. */ +union kr_in_addr { + struct in_addr ip4; + struct in6_addr ip6; +}; + +/* TODO: rename kr_inaddr functions to kr_sockaddr */ +/** Address bytes for given family. */ +KR_EXPORT KR_PURE +const char *kr_inaddr(const struct sockaddr *addr); +/** Address family. */ +KR_EXPORT KR_PURE +int kr_inaddr_family(const struct sockaddr *addr); +/** Address length for given family, i.e. sizeof(struct in*_addr). */ +KR_EXPORT KR_PURE +int kr_inaddr_len(const struct sockaddr *addr); +/** Sockaddr length for given family, i.e. sizeof(struct sockaddr_in*). */ +KR_EXPORT KR_PURE +int kr_sockaddr_len(const struct sockaddr *addr); + +/** Creates a packed structure from the specified `addr`, safe for use as a key + * in containers like `trie_t`, and writes it into `dst`. On success, returns + * the actual length of the key. + * + * Returns `kr_error(EAFNOSUPPORT)` if the family of `addr` is unsupported. */ +KR_EXPORT +ssize_t kr_sockaddr_key(struct kr_sockaddr_key_storage *dst, + const struct sockaddr *addr); + +/** Creates a `struct sockaddr` from the specified `key` created using the + * `kr_sockaddr_key()` function. */ +KR_EXPORT +struct sockaddr *kr_sockaddr_from_key(struct sockaddr_storage *dst, + const char *key); + +/** Checks whether the two keys represent the same address; + * does NOT compare the ports. */ +KR_EXPORT +bool kr_sockaddr_key_same_addr(const char *key_a, const char *key_b); + +/** Compare two given sockaddr. + * return 0 - addresses are equal, error code otherwise. + */ +KR_EXPORT KR_PURE +int kr_sockaddr_cmp(const struct sockaddr *left, const struct sockaddr *right); +/** Port. */ +KR_EXPORT KR_PURE +uint16_t kr_inaddr_port(const struct sockaddr *addr); +/** Set port. */ +KR_EXPORT +void kr_inaddr_set_port(struct sockaddr *addr, uint16_t port); + +/** Write string representation for given address as "<addr>#<port>". + * \param[in] addr the raw address + * \param[out] buf the buffer for output string + * \param[in,out] buflen the available(in) and utilized(out) length, including \0 */ +KR_EXPORT +int kr_inaddr_str(const struct sockaddr *addr, char *buf, size_t *buflen); + +/** Write string representation for given address as "<addr>#<port>". + * It's the same as kr_inaddr_str(), but the input address is input in native format + * like for inet_ntop() (4 or 16 bytes) and port must be separate parameter. */ +KR_EXPORT +int kr_ntop_str(int family, const void *src, uint16_t port, char *buf, size_t *buflen); + +/** @internal Create string representation addr#port. + * @return pointer to a *static* string, i.e. each call will overwrite it + */ +KR_EXPORT +char *kr_straddr(const struct sockaddr *addr); + +/** Return address type for string. */ +KR_EXPORT KR_PURE +int kr_straddr_family(const char *addr); +/** Return address length in given family (struct in*_addr). */ +KR_EXPORT KR_CONST +int kr_family_len(int family); + +/** Create a sockaddr* from string+port representation. + * Also accepts IPv6 link-local and AF_UNIX starting with "/" (ignoring port) */ +KR_EXPORT +struct sockaddr * kr_straddr_socket(const char *addr, int port, knot_mm_t *pool); + +/** Parse address and return subnet length (bits). + * @warning 'dst' must be at least `sizeof(struct in6_addr)` long. */ +KR_EXPORT +int kr_straddr_subnet(void *dst, const char *addr); + +/** Splits ip address specified as "addr@port" or "addr#port" into addr and port. + * \param[in] instr zero-terminated input, e.g. "192.0.2.1#12345\0" + * \param[out] ipaddr working buffer for the port-less prefix of instr; + * length >= INET6_ADDRSTRLEN + 1. + * \param[out] port written in case it's specified in instr + * \return error code + * \note Typically you follow this by kr_straddr_socket(). + * \note Only internet addresses are supported, i.e. no AF_UNIX sockets. + */ +KR_EXPORT +int kr_straddr_split(const char *instr, char ipaddr[static restrict (INET6_ADDRSTRLEN + 1)], + uint16_t *port); + +/** Formats ip address and port in "addr#port" format. + * and performs validation. + * @note Port always formatted as five-character string with leading zeros. + * @return kr_error(EINVAL) - addr or buf is NULL or buflen is 0 or + * addr doesn't contain a valid ip address + * kr_error(ENOSP) - buflen is too small + */ +KR_EXPORT +int kr_straddr_join(const char *addr, uint16_t port, char *buf, size_t *buflen); + +/** Compare memory bitwise. The semantics is "the same" as for memcmp(). + * The partial byte is considered with more-significant bits first, + * so this is e.g. suitable for comparing IP prefixes. */ +KR_EXPORT KR_PURE +int kr_bitcmp(const char *a, const char *b, int bits); + +/** Masks bits. The specified number of bits in `a` from the left (network order) + * will remain their original value, while the rest will be set to zero. + * This is useful for storing network addresses in a trie. */ +KR_EXPORT +void kr_bitmask(unsigned char *a, size_t a_len, int bits); + +/** Check whether `addr` points to an `AF_INET6` address and whether the address + * is link-local. */ +static inline bool kr_sockaddr_link_local(const struct sockaddr *addr) +{ + if (addr->sa_family != AF_INET6) + return false; + + /* Link-local: https://tools.ietf.org/html/rfc4291#section-2.4 */ + const uint8_t prefix[] = { 0xFE, 0x80 }; + const struct sockaddr_in6 *ip6 = (const struct sockaddr_in6 *) addr; + return kr_bitcmp((char *) ip6->sin6_addr.s6_addr, (char *) prefix, 10) == 0; +} + +/* Stash key = {[5] class, [1-255] owner, [5] type, [5] additional, [1] \x00 } */ +#define KR_RRKEY_LEN (16 + KNOT_DNAME_MAXLEN) +/** Create unique null-terminated string key for RR. + * @param key Destination buffer for key size, MUST be KR_RRKEY_LEN or larger. + * @param class RR class. + * @param owner RR owner name. + * @param type RR type. + * @param additional flags (for instance can be used for storing covered type + * when RR type is RRSIG). + * @return key length if successful or an error + * */ +KR_EXPORT +int kr_rrkey(char *key, uint16_t class, const knot_dname_t *owner, + uint16_t type, uint16_t additional); + +/** Add RRSet copy to a ranked RR array. + * + * To convert to standard RRs inside, you need to call _finalize() afterwards, + * and the memory of rr->rrs.rdata has to remain until then. + * + * \return array index (>= 0) or error code (< 0) + */ +KR_EXPORT +int kr_ranked_rrarray_add(ranked_rr_array_t *array, const knot_rrset_t *rr, + uint8_t rank, bool to_wire, uint32_t qry_uid, knot_mm_t *pool); +/** Finalize in_progress sets - all with matching qry_uid. */ +KR_EXPORT +int kr_ranked_rrarray_finalize(ranked_rr_array_t *array, uint32_t qry_uid, knot_mm_t *pool); + +/** @internal Mark the RRSets from particular query as + * "have (not) to be recorded in the final answer". + * @param array RRSet array. + * @param to_wire Records must be\must not be recorded in final answer. + * @param qry_uid Query uid. + * @param check_dups When to_wire is true, try to avoid duplicate RRSets. + * @param extraCheck optional function checking whether to consider the record + * @return 0 or an error + */ +int kr_ranked_rrarray_set_wire(ranked_rr_array_t *array, bool to_wire, + uint32_t qry_uid, bool check_dups, + bool (*extraCheck)(const ranked_rr_array_entry_t *)); + + +/** Style used by the kr_*_text() functions. */ +KR_EXPORT extern +const knot_dump_style_t KR_DUMP_STYLE_DEFAULT; + +/** + * @return Newly allocated string representation of packet. + * Caller has to free() returned string. + */ +KR_EXPORT +char *kr_pkt_text(const knot_pkt_t *pkt); + +KR_PURE +char *kr_rrset_text(const knot_rrset_t *rr); + +KR_PURE +static inline char *kr_dname_text(const knot_dname_t *name) { + return knot_dname_to_str_alloc(name); +} + +KR_CONST +static inline char *kr_rrtype_text(const uint16_t rrtype) { + char type_str[32] = {0}; + knot_rrtype_to_string(rrtype, type_str, sizeof(type_str)); + return strdup(type_str); +} + +/** + * Call module property. + */ +KR_EXPORT +char *kr_module_call(struct kr_context *ctx, const char *module, const char *prop, const char *input); + +/** Swap two places. Note: the parameters need to be without side effects. */ +#define SWAP(x, y) do { /* http://stackoverflow.com/a/3982430/587396 */ \ + unsigned char swap_temp[sizeof(x) == sizeof(y) ? (ssize_t)sizeof(x) : -1]; \ + memcpy(swap_temp, &y, sizeof(x)); \ + memcpy(&y, &x, sizeof(x)); \ + memcpy(&x, swap_temp, sizeof(x)); \ + } while(0) + +/** Return the (covered) type of an nonempty RRset. */ +static inline uint16_t kr_rrset_type_maysig(const knot_rrset_t *rr) +{ + kr_require(rr && rr->rrs.count && rr->rrs.rdata); + uint16_t type = rr->type; + if (type == KNOT_RRTYPE_RRSIG) + type = knot_rrsig_type_covered(rr->rrs.rdata); + return type; +} + +/** The current time in monotonic milliseconds. + * + * \note it may be outdated in case of long callbacks; see uv_now(). + */ +KR_EXPORT +uint64_t kr_now(void); + +/** Call free(handle->data); it's useful e.g. as a callback in uv_close(). */ +KR_EXPORT void kr_uv_free_cb(uv_handle_t* handle); + +/** Convert name from lookup format to wire. See knot_dname_lf + * + * \note len bytes are read and len+1 are written with *normal* LF, + * but it's also allowed that the final zero byte is omitted in LF. + * \return the number of bytes written (>0) or error code (<0) + */ +int knot_dname_lf2wire(knot_dname_t *dst, uint8_t len, const uint8_t *lf); + +/** Patched knot_dname_lf. LF for "." has length zero instead of one, for consistency. + * (TODO: consistency?) + * \param add_wildcard append the wildcard label + * \note packet is always NULL + */ +static inline int kr_dname_lf(uint8_t *dst, const knot_dname_t *src, bool add_wildcard) +{ + knot_dname_storage_t right_aligned_dst; + uint8_t *right_aligned_dname_start = knot_dname_lf(src, right_aligned_dst); + if (!right_aligned_dname_start) { + return kr_error(EINVAL); + } + int len = right_aligned_dname_start[0]; + if (kr_fails_assert(right_aligned_dname_start + 1 + len - KNOT_DNAME_MAXLEN == right_aligned_dst)) + return kr_error(EINVAL); + memcpy(dst + 1, right_aligned_dname_start + 1, len); + if (add_wildcard) { + if (len + 2 > KNOT_DNAME_MAXLEN) + return kr_error(ENOSPC); + dst[len + 1] = '*'; + dst[len + 2] = '\0'; + len += 2; + } + dst[0] = len; + return KNOT_EOK; +} + + +/** Timer, i.e stop-watch. */ +typedef struct timespec kr_timer_t; + +/** Start, i.e. set the reference point. */ +static inline void kr_timer_start(kr_timer_t *start) +{ + /* The call should be very reliable, but let's check it in _start() at least. */ + kr_require(start && clock_gettime(CLOCK_MONOTONIC, start) == 0); +} + +/** Get elapsed time in floating-point seconds. */ +static inline double kr_timer_elapsed(kr_timer_t *start) +{ + kr_require(start); + kr_timer_t end = { 0 }; + (void)clock_gettime(CLOCK_MONOTONIC, &end); + return (end.tv_sec - start->tv_sec) + (double)(end.tv_nsec - start->tv_nsec) / 1e9; +} + +/** Get elapsed time in micro-seconds. */ +static inline uint64_t kr_timer_elapsed_us(kr_timer_t *start) +{ + kr_require(start); + kr_timer_t end = { 0 }; + (void)clock_gettime(CLOCK_MONOTONIC, &end); + // avoid negative differences, because of integer division + if (end.tv_nsec - start->tv_nsec < 0) { + end.tv_nsec += 1000*1000*1000; + end.tv_sec -= 1; + } + return (uint64_t)(end.tv_sec - start->tv_sec) * 1000000 + // adding 500 gives us rounding + + (end.tv_nsec - start->tv_nsec + 500) / 1000; +} + + +/** + * Difference between two calendar times specified as strings. + * \param[in] format format for strptime + * \param[out] diff result from C difftime(time1, time0) + */ +KR_EXPORT +const char *kr_strptime_diff(const char *format, const char *time1_str, + const char *time0_str, double *diff); + +/* Trivial non-inline wrappers, to be used in lua. */ +KR_EXPORT void kr_rrset_init(knot_rrset_t *rrset, knot_dname_t *owner, + uint16_t type, uint16_t rclass, uint32_t ttl); +KR_EXPORT bool kr_pkt_has_wire(const knot_pkt_t *pkt); +KR_EXPORT bool kr_pkt_has_dnssec(const knot_pkt_t *pkt); +KR_EXPORT uint16_t kr_pkt_qclass(const knot_pkt_t *pkt); +KR_EXPORT uint16_t kr_pkt_qtype(const knot_pkt_t *pkt); +KR_EXPORT uint32_t kr_rrsig_sig_inception(const knot_rdata_t *rdata); +KR_EXPORT uint32_t kr_rrsig_sig_expiration(const knot_rdata_t *rdata); +KR_EXPORT uint16_t kr_rrsig_type_covered(const knot_rdata_t *rdata); + +KR_EXPORT time_t kr_file_mtime (const char* fname); +/** Return filesystem size in bytes. */ +KR_EXPORT long long kr_fssize(const char *path); +/** Simply return de->dname. (useful from Lua) */ +KR_EXPORT const char * kr_dirent_name(const struct dirent *de); + + +/* trivial libknot versions compatibility */ +static inline size_t kr_dname_prefixlen(const uint8_t *name, unsigned nlabels) +{ + return knot_dname_prefixlen(name, nlabels + #if KNOT_VERSION_HEX < 0x030400 + , NULL + #endif + ); +} + |