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Diffstat (limited to 'src/feature/nodelist/nodefamily.c')
| -rw-r--r-- | src/feature/nodelist/nodefamily.c | 416 |
1 files changed, 416 insertions, 0 deletions
diff --git a/src/feature/nodelist/nodefamily.c b/src/feature/nodelist/nodefamily.c new file mode 100644 index 0000000000..feaa3730dc --- /dev/null +++ b/src/feature/nodelist/nodefamily.c @@ -0,0 +1,416 @@ +/* Copyright (c) 2001 Matej Pfajfar. + * Copyright (c) 2001-2004, Roger Dingledine. + * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson. + * Copyright (c) 2007-2020, The Tor Project, Inc. */ +/* See LICENSE for licensing information */ + +/** + * \file nodefamily.c + * \brief Code to manipulate encoded, reference-counted node families. We + * use these tricks to save space, since these families would otherwise + * require a large number of tiny allocations. + **/ + +#include "core/or/or.h" +#include "feature/nodelist/nickname.h" +#include "feature/nodelist/nodefamily.h" +#include "feature/nodelist/nodefamily_st.h" +#include "feature/nodelist/nodelist.h" +#include "feature/relay/router.h" +#include "feature/nodelist/routerlist.h" + +#include "ht.h" +#include "siphash.h" + +#include "lib/container/smartlist.h" +#include "lib/ctime/di_ops.h" +#include "lib/defs/digest_sizes.h" +#include "lib/log/util_bug.h" + +#include <stdlib.h> +#include <string.h> + +/** + * Allocate and return a blank node family with space to hold <b>n_members</b> + * members. + */ +static nodefamily_t * +nodefamily_alloc(int n_members) +{ + size_t alloc_len = offsetof(nodefamily_t, family_members) + + NODEFAMILY_ARRAY_SIZE(n_members); + nodefamily_t *nf = tor_malloc_zero(alloc_len); + nf->n_members = n_members; + return nf; +} + +/** + * Hashtable hash implementation. + */ +static inline unsigned int +nodefamily_hash(const nodefamily_t *nf) +{ + return (unsigned) siphash24g(nf->family_members, + NODEFAMILY_ARRAY_SIZE(nf->n_members)); +} + +/** + * Hashtable equality implementation. + */ +static inline unsigned int +nodefamily_eq(const nodefamily_t *a, const nodefamily_t *b) +{ + return (a->n_members == b->n_members) && + fast_memeq(a->family_members, b->family_members, + NODEFAMILY_ARRAY_SIZE(a->n_members)); +} + +static HT_HEAD(nodefamily_map, nodefamily_t) the_node_families + = HT_INITIALIZER(); + +HT_PROTOTYPE(nodefamily_map, nodefamily_t, ht_ent, nodefamily_hash, + nodefamily_eq); +HT_GENERATE2(nodefamily_map, nodefamily_t, ht_ent, nodefamily_hash, + node_family_eq, 0.6, tor_reallocarray_, tor_free_); + +/** + * Parse the family declaration in <b>s</b>, returning the canonical + * <b>nodefamily_t</b> for its members. Return NULL on error. + * + * If <b>rsa_id_self</b> is provided, it is a DIGEST_LEN-byte digest + * for the router that declared this family: insert it into the + * family declaration if it is not there already. + * + * If NF_WARN_MALFORMED is set in <b>flags</b>, warn about any + * elements that we can't parse. (By default, we log at info.) + * + * If NF_REJECT_MALFORMED is set in <b>flags</b>, treat any unparseable + * elements as an error. (By default, we simply omit them.) + **/ +nodefamily_t * +nodefamily_parse(const char *s, const uint8_t *rsa_id_self, + unsigned flags) +{ + smartlist_t *sl = smartlist_new(); + smartlist_split_string(sl, s, NULL, SPLIT_SKIP_SPACE|SPLIT_IGNORE_BLANK, 0); + nodefamily_t *result = nodefamily_from_members(sl, rsa_id_self, flags, NULL); + SMARTLIST_FOREACH(sl, char *, cp, tor_free(cp)); + smartlist_free(sl); + return result; +} + +/** + * Canonicalize the family list <b>s</b>, returning a newly allocated string. + * + * The canonicalization rules are fully specified in dir-spec.txt, but, + * briefly: $hexid entries are put in caps, $hexid[=~]foo entries are + * truncated, nicknames are put into lowercase, unrecognized entries are left + * alone, and everything is sorted. + **/ +char * +nodefamily_canonicalize(const char *s, const uint8_t *rsa_id_self, + unsigned flags) +{ + smartlist_t *sl = smartlist_new(); + smartlist_t *result_members = smartlist_new(); + smartlist_split_string(sl, s, NULL, SPLIT_SKIP_SPACE|SPLIT_IGNORE_BLANK, 0); + nodefamily_t *nf = nodefamily_from_members(sl, rsa_id_self, flags, + result_members); + + char *formatted = nodefamily_format(nf); + smartlist_split_string(result_members, formatted, NULL, + SPLIT_SKIP_SPACE|SPLIT_IGNORE_BLANK, 0); + smartlist_sort_strings(result_members); + char *combined = smartlist_join_strings(result_members, " ", 0, NULL); + + nodefamily_free(nf); + SMARTLIST_FOREACH(sl, char *, cp, tor_free(cp)); + smartlist_free(sl); + SMARTLIST_FOREACH(result_members, char *, cp, tor_free(cp)); + smartlist_free(result_members); + tor_free(formatted); + + return combined; +} + +/** + * qsort helper for encoded nodefamily elements. + **/ +static int +compare_members(const void *a, const void *b) +{ + return fast_memcmp(a, b, NODEFAMILY_MEMBER_LEN); +} + +/** + * Parse the member strings in <b>members</b>, returning their canonical + * <b>nodefamily_t</b>. Return NULL on error. + * + * If <b>rsa_id_self</b> is provided, it is a DIGEST_LEN-byte digest + * for the router that declared this family: insert it into the + * family declaration if it is not there already. + * + * The <b>flags</b> element is interpreted as in nodefamily_parse(). + * + * If <b>unrecognized</b> is provided, fill it copies of any unrecognized + * members. (Note that malformed $hexids are not considered unrecognized.) + **/ +nodefamily_t * +nodefamily_from_members(const smartlist_t *members, + const uint8_t *rsa_id_self, + unsigned flags, + smartlist_t *unrecognized_out) +{ + const int n_self = rsa_id_self ? 1 : 0; + int n_bad_elements = 0; + int n_members = smartlist_len(members) + n_self; + nodefamily_t *tmp = nodefamily_alloc(n_members); + uint8_t *ptr = NODEFAMILY_MEMBER_PTR(tmp, 0); + + SMARTLIST_FOREACH_BEGIN(members, const char *, cp) { + bool bad_element = true; + if (is_legal_nickname(cp)) { + ptr[0] = NODEFAMILY_BY_NICKNAME; + tor_assert(strlen(cp) < DIGEST_LEN); // guaranteed by is_legal_nickname + memcpy(ptr+1, cp, strlen(cp)); + tor_strlower((char*) ptr+1); + bad_element = false; + } else if (is_legal_hexdigest(cp)) { + char digest_buf[DIGEST_LEN]; + char nn_buf[MAX_NICKNAME_LEN+1]; + char nn_char=0; + if (hex_digest_nickname_decode(cp, digest_buf, &nn_char, nn_buf)==0) { + bad_element = false; + ptr[0] = NODEFAMILY_BY_RSA_ID; + memcpy(ptr+1, digest_buf, DIGEST_LEN); + } + } else { + if (unrecognized_out) + smartlist_add_strdup(unrecognized_out, cp); + } + + if (bad_element) { + const int severity = (flags & NF_WARN_MALFORMED) ? LOG_WARN : LOG_INFO; + log_fn(severity, LD_GENERAL, + "Bad element %s while parsing a node family.", + escaped(cp)); + ++n_bad_elements; + } else { + ptr += NODEFAMILY_MEMBER_LEN; + } + } SMARTLIST_FOREACH_END(cp); + + if (n_bad_elements && (flags & NF_REJECT_MALFORMED)) + goto err; + + if (rsa_id_self) { + /* Add self. */ + ptr[0] = NODEFAMILY_BY_RSA_ID; + memcpy(ptr+1, rsa_id_self, DIGEST_LEN); + } + + n_members -= n_bad_elements; + + /* Sort tmp into canonical order. */ + qsort(tmp->family_members, n_members, NODEFAMILY_MEMBER_LEN, + compare_members); + + /* Remove duplicates. */ + int i; + for (i = 0; i < n_members-1; ++i) { + uint8_t *thisptr = NODEFAMILY_MEMBER_PTR(tmp, i); + uint8_t *nextptr = NODEFAMILY_MEMBER_PTR(tmp, i+1); + if (fast_memeq(thisptr, nextptr, NODEFAMILY_MEMBER_LEN)) { + memmove(thisptr, nextptr, (n_members-i-1)*NODEFAMILY_MEMBER_LEN); + --n_members; + --i; + } + } + int n_members_alloc = tmp->n_members; + tmp->n_members = n_members; + + /* See if we already allocated this family. */ + nodefamily_t *found = HT_FIND(nodefamily_map, &the_node_families, tmp); + if (found) { + /* If we did, great: incref it and return it. */ + ++found->refcnt; + tor_free(tmp); + return found; + } else { + /* If not, insert it into the hashtable. */ + if (n_members_alloc != n_members) { + /* Compact the family if needed */ + nodefamily_t *tmp2 = nodefamily_alloc(n_members); + memcpy(tmp2->family_members, tmp->family_members, + n_members * NODEFAMILY_MEMBER_LEN); + tor_free(tmp); + tmp = tmp2; + } + + tmp->refcnt = 1; + HT_INSERT(nodefamily_map, &the_node_families, tmp); + return tmp; + } + + err: + tor_free(tmp); + return NULL; +} + +/** + * Drop our reference to <b>family</b>, freeing it if there are no more + * references. + */ +void +nodefamily_free_(nodefamily_t *family) +{ + if (family == NULL) + return; + + --family->refcnt; + + if (family->refcnt == 0) { + HT_REMOVE(nodefamily_map, &the_node_families, family); + tor_free(family); + } +} + +/** + * Return true iff <b>family</b> contains the SHA1 RSA1024 identity + * <b>rsa_id</b>. + */ +bool +nodefamily_contains_rsa_id(const nodefamily_t *family, + const uint8_t *rsa_id) +{ + if (family == NULL) + return false; + + unsigned i; + for (i = 0; i < family->n_members; ++i) { + const uint8_t *ptr = NODEFAMILY_MEMBER_PTR(family, i); + if (ptr[0] == NODEFAMILY_BY_RSA_ID && + fast_memeq(ptr+1, rsa_id, DIGEST_LEN)) { + return true; + } + } + return false; +} + +/** + * Return true iff <b>family</b> contains the nickname <b>name</b>. + */ +bool +nodefamily_contains_nickname(const nodefamily_t *family, + const char *name) +{ + if (family == NULL) + return false; + + unsigned i; + for (i = 0; i < family->n_members; ++i) { + const uint8_t *ptr = NODEFAMILY_MEMBER_PTR(family, i); + // note that the strcasecmp() is safe because there is always at least one + // NUL in the encoded nickname, because all legal nicknames are less than + // DIGEST_LEN bytes long. + if (ptr[0] == NODEFAMILY_BY_NICKNAME && !strcasecmp((char*)ptr+1, name)) { + return true; + } + } + return false; +} + +/** + * Return true if <b>family</b> contains the nickname or the RSA ID for + * <b>node</b> + **/ +bool +nodefamily_contains_node(const nodefamily_t *family, + const node_t *node) +{ + return + nodefamily_contains_nickname(family, node_get_nickname(node)) + || + nodefamily_contains_rsa_id(family, node_get_rsa_id_digest(node)); +} + +/** + * Look up every entry in <b>family</b>, and add add the corresponding + * node_t to <b>out</b>. + **/ +void +nodefamily_add_nodes_to_smartlist(const nodefamily_t *family, + smartlist_t *out) +{ + if (!family) + return; + + unsigned i; + for (i = 0; i < family->n_members; ++i) { + const uint8_t *ptr = NODEFAMILY_MEMBER_PTR(family, i); + const node_t *node = NULL; + switch (ptr[0]) { + case NODEFAMILY_BY_NICKNAME: + node = node_get_by_nickname((char*)ptr+1, NNF_NO_WARN_UNNAMED); + break; + case NODEFAMILY_BY_RSA_ID: + node = node_get_by_id((char*)ptr+1); + break; + default: + /* LCOV_EXCL_START */ + tor_assert_nonfatal_unreached(); + break; + /* LCOV_EXCL_STOP */ + } + if (node) + smartlist_add(out, (void *)node); + } +} + +/** + * Encode <b>family</b> as a space-separated string. + */ +char * +nodefamily_format(const nodefamily_t *family) +{ + if (!family) + return tor_strdup(""); + + unsigned i; + smartlist_t *sl = smartlist_new(); + for (i = 0; i < family->n_members; ++i) { + const uint8_t *ptr = NODEFAMILY_MEMBER_PTR(family, i); + switch (ptr[0]) { + case NODEFAMILY_BY_NICKNAME: + smartlist_add_strdup(sl, (char*)ptr+1); + break; + case NODEFAMILY_BY_RSA_ID: { + char buf[HEX_DIGEST_LEN+2]; + buf[0]='$'; + base16_encode(buf+1, sizeof(buf)-1, (char*)ptr+1, DIGEST_LEN); + tor_strupper(buf); + smartlist_add_strdup(sl, buf); + break; + } + default: + /* LCOV_EXCL_START */ + tor_assert_nonfatal_unreached(); + break; + /* LCOV_EXCL_STOP */ + } + } + + char *result = smartlist_join_strings(sl, " ", 0, NULL); + SMARTLIST_FOREACH(sl, char *, cp, tor_free(cp)); + smartlist_free(sl); + return result; +} + +/** + * Free all storage held in the nodefamily map. + **/ +void +nodefamily_free_all(void) +{ + HT_CLEAR(nodefamily_map, &the_node_families); +} |