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Diffstat (limited to 'src/gsm/gsm0808_utils.c')
| -rw-r--r-- | src/gsm/gsm0808_utils.c | 145 |
1 files changed, 145 insertions, 0 deletions
diff --git a/src/gsm/gsm0808_utils.c b/src/gsm/gsm0808_utils.c index 9fcccaec..54ec19c2 100644 --- a/src/gsm/gsm0808_utils.c +++ b/src/gsm/gsm0808_utils.c @@ -1391,6 +1391,151 @@ int gsm0808_cell_id_u_name(char *buf, size_t buflen, } } +/* Store individual Cell Identifier information in a CGI, without clearing the remaining ones. + * This is useful to supplement one CGI with information from more than one Cell Identifier, + * which in turn is useful to match Cell Identifiers of differing kinds to each other. + * Before first invocation, clear the *dst struct externally, this function does only write those members + * that are present in parameter u. + */ +static void cell_id_to_cgi(struct osmo_cell_global_id *dst, + enum CELL_IDENT discr, const union gsm0808_cell_id_u *u) +{ + switch (discr) { + case CELL_IDENT_WHOLE_GLOBAL: + *dst = u->global; + return; + + case CELL_IDENT_LAC_AND_CI: + dst->lai.lac = u->lac_and_ci.lac; + dst->cell_identity = u->lac_and_ci.ci; + return; + + case CELL_IDENT_CI: + dst->cell_identity = u->ci; + return; + + case CELL_IDENT_LAI_AND_LAC: + dst->lai = u->lai_and_lac; + return; + + case CELL_IDENT_LAC: + dst->lai.lac = u->lac; + return; + + case CELL_IDENT_NO_CELL: + case CELL_IDENT_BSS: + case CELL_IDENT_UTRAN_PLMN_LAC_RNC: + case CELL_IDENT_UTRAN_RNC: + case CELL_IDENT_UTRAN_LAC_RNC: + /* No values to set. */ + return; + } +} + +/*! Return true if the common information between the two Cell Identifiers match. + * For example, if a LAC+CI is compared to LAC, return true if the LAC are the same. + * Note that CELL_IDENT_NO_CELL will always return false. + * Also CELL_IDENT_BSS will always return false, since this function cannot possibly + * know the bounds of the BSS, so the caller must handle CELL_IDENT_BSS specially. + * \param[in] discr1 Cell Identifier type. + * \param[in] u1 Cell Identifier value. + * \param[in] discr2 Other Cell Identifier type. + * \param[in] u2 Other Cell Identifier value. + * \param[in] exact_match If true, return true only if the CELL_IDENT types and all values are identical. + * \returns True if the common fields of the above match. + */ +static bool gsm0808_cell_id_u_match(enum CELL_IDENT discr1, const union gsm0808_cell_id_u *u1, + enum CELL_IDENT discr2, const union gsm0808_cell_id_u *u2, + bool exact_match) +{ + struct osmo_cell_global_id a = {}; + struct osmo_cell_global_id b = {}; + + if (exact_match && discr1 != discr2) + return false; + + /* First handle the odd wildcard like CELL_IDENT kinds. We can't really match any of these. */ + switch (discr1) { + case CELL_IDENT_NO_CELL: + case CELL_IDENT_BSS: + return discr1 == discr2; + case CELL_IDENT_UTRAN_PLMN_LAC_RNC: + case CELL_IDENT_UTRAN_RNC: + case CELL_IDENT_UTRAN_LAC_RNC: + return false; + default: + break; + } + switch (discr2) { + case CELL_IDENT_NO_CELL: + case CELL_IDENT_UTRAN_PLMN_LAC_RNC: + case CELL_IDENT_UTRAN_RNC: + case CELL_IDENT_UTRAN_LAC_RNC: + case CELL_IDENT_BSS: + return false; + default: + break; + } + + /* Enrich both sides to full CGI, then compare those. First set the *other* ID's values in case + * they assign more items. For example: + * u1 = LAC:42 + * u2 = LAC+CI:23+5 + * 1) a <- LAC+CI:23+5 + * 2) a <- LAC:42 so that a = LAC+CI:42+5 + * Now we can compare those two and find a mismatch. If the LAC were the same, we would get + * identical LAC+CI and hence a match. */ + + cell_id_to_cgi(&a, discr2, u2); + cell_id_to_cgi(&a, discr1, u1); + + cell_id_to_cgi(&b, discr1, u1); + cell_id_to_cgi(&b, discr2, u2); + + return osmo_cgi_cmp(&a, &b) == 0; +} + +/*! Return true if the common information between the two Cell Identifiers match. + * For example, if a LAC+CI is compared to LAC, return true if the LAC are the same. + * Note that CELL_IDENT_NO_CELL will always return false. + * Also CELL_IDENT_BSS will always return false, since this function cannot possibly + * know the bounds of the BSS, so the caller must handle CELL_IDENT_BSS specially. + * \param[in] id1 Cell Identifier. + * \param[in] id2 Other Cell Identifier. + * \param[in] exact_match If true, return true only if the CELL_IDENT types and all values are identical. + * \returns True if the common fields of the above match. + */ +bool gsm0808_cell_ids_match(const struct gsm0808_cell_id *id1, const struct gsm0808_cell_id *id2, bool exact_match) +{ + return gsm0808_cell_id_u_match(id1->id_discr, &id1->id, id2->id_discr, &id2->id, exact_match); +} + +/*! Find an index in a Cell Identifier list that matches a given single Cell Identifer. + * Compare \a id against each entry in \a list using gsm0808_cell_ids_match(), and return the list index + * if a match is found. \a match_nr allows iterating all matches in the list. A match_nr <= 0 returns the + * first match in the list, match_nr == 1 the second match, etc., and if match_nr exceeds the available + * matches in the list, -1 is returned. + * \param[in] id Cell Identifier to match. + * \param[in] list Cell Identifier list to search in. + * \param[in] match_nr Ignore this many matches. + * \param[in] exact_match If true, consider as match only if the CELL_IDENT types and all values are identical. + * \returns -1 if no match is found, list index if a match is found. + */ +int gsm0808_cell_id_matches_list(const struct gsm0808_cell_id *id, const struct gsm0808_cell_id_list2 *list, + unsigned int match_nr, bool exact_match) +{ + int i; + for (i = 0; i < list->id_list_len; i++) { + if (gsm0808_cell_id_u_match(id->id_discr, &id->id, list->id_discr, &list->id_list[i], exact_match)) { + if (match_nr) + match_nr--; + else + return i; + } + } + return -1; +} + /*! value_string[] for enum CELL_IDENT. */ const struct value_string gsm0808_cell_id_discr_names[] = { { CELL_IDENT_WHOLE_GLOBAL, "CGI" }, |