/*************************************************************************** * _ _ ____ _ * Project ___| | | | _ \| | * / __| | | | |_) | | * | (__| |_| | _ <| |___ * \___|\___/|_| \_\_____| * * Copyright (C) 1998 - 2017, Daniel Stenberg, , et al. * * This software is licensed as described in the file COPYING, which * you should have received as part of this distribution. The terms * are also available at https://curl.haxx.se/docs/copyright.html. * * You may opt to use, copy, modify, merge, publish, distribute and/or sell * copies of the Software, and permit persons to whom the Software is * furnished to do so, under the terms of the COPYING file. * * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY * KIND, either express or implied. * ***************************************************************************/ #include "curl_setup.h" #ifdef HAVE_LIMITS_H #include #endif #ifdef HAVE_NETINET_IN_H #include #endif #ifdef HAVE_NETDB_H #include #endif #ifdef HAVE_ARPA_INET_H #include #endif #ifdef __VMS #include #include #endif #ifdef HAVE_PROCESS_H #include #endif #if (defined(NETWARE) && defined(__NOVELL_LIBC__)) #undef in_addr_t #define in_addr_t unsigned long #endif /*********************************************************************** * Only for ares-enabled builds * And only for functions that fulfill the asynch resolver backend API * as defined in asyn.h, nothing else belongs in this file! **********************************************************************/ #ifdef CURLRES_ARES #include "urldata.h" #include "sendf.h" #include "hostip.h" #include "hash.h" #include "share.h" #include "strerror.h" #include "url.h" #include "multiif.h" #include "inet_pton.h" #include "connect.h" #include "select.h" #include "progress.h" # if defined(CURL_STATICLIB) && !defined(CARES_STATICLIB) && \ (defined(WIN32) || defined(_WIN32) || defined(__SYMBIAN32__)) # define CARES_STATICLIB # endif # include # include /* really old c-ares didn't include this by itself */ #if ARES_VERSION >= 0x010500 /* c-ares 1.5.0 or later, the callback proto is modified */ #define HAVE_CARES_CALLBACK_TIMEOUTS 1 #endif /* The last 3 #include files should be in this order */ #include "curl_printf.h" #include "curl_memory.h" #include "memdebug.h" struct ResolverResults { int num_pending; /* number of ares_gethostbyname() requests */ Curl_addrinfo *temp_ai; /* intermediary result while fetching c-ares parts */ int last_status; }; /* * Curl_resolver_global_init() - the generic low-level asynchronous name * resolve API. Called from curl_global_init() to initialize global resolver * environment. Initializes ares library. */ int Curl_resolver_global_init(void) { #ifdef CARES_HAVE_ARES_LIBRARY_INIT if(ares_library_init(ARES_LIB_INIT_ALL)) { return CURLE_FAILED_INIT; } #endif return CURLE_OK; } /* * Curl_resolver_global_cleanup() * * Called from curl_global_cleanup() to destroy global resolver environment. * Deinitializes ares library. */ void Curl_resolver_global_cleanup(void) { #ifdef CARES_HAVE_ARES_LIBRARY_CLEANUP ares_library_cleanup(); #endif } /* * Curl_resolver_init() * * Called from curl_easy_init() -> Curl_open() to initialize resolver * URL-state specific environment ('resolver' member of the UrlState * structure). Fills the passed pointer by the initialized ares_channel. */ CURLcode Curl_resolver_init(void **resolver) { int status = ares_init((ares_channel*)resolver); if(status != ARES_SUCCESS) { if(status == ARES_ENOMEM) return CURLE_OUT_OF_MEMORY; else return CURLE_FAILED_INIT; } return CURLE_OK; /* make sure that all other returns from this function should destroy the ares channel before returning error! */ } /* * Curl_resolver_cleanup() * * Called from curl_easy_cleanup() -> Curl_close() to cleanup resolver * URL-state specific environment ('resolver' member of the UrlState * structure). Destroys the ares channel. */ void Curl_resolver_cleanup(void *resolver) { ares_destroy((ares_channel)resolver); } /* * Curl_resolver_duphandle() * * Called from curl_easy_duphandle() to duplicate resolver URL-state specific * environment ('resolver' member of the UrlState structure). Duplicates the * 'from' ares channel and passes the resulting channel to the 'to' pointer. */ int Curl_resolver_duphandle(void **to, void *from) { /* Clone the ares channel for the new handle */ if(ARES_SUCCESS != ares_dup((ares_channel*)to, (ares_channel)from)) return CURLE_FAILED_INIT; return CURLE_OK; } static void destroy_async_data(struct Curl_async *async); /* * Cancel all possibly still on-going resolves for this connection. */ void Curl_resolver_cancel(struct connectdata *conn) { if(conn->data && conn->data->state.resolver) ares_cancel((ares_channel)conn->data->state.resolver); destroy_async_data(&conn->async); } /* * destroy_async_data() cleans up async resolver data. */ static void destroy_async_data(struct Curl_async *async) { free(async->hostname); if(async->os_specific) { struct ResolverResults *res = (struct ResolverResults *)async->os_specific; if(res) { if(res->temp_ai) { Curl_freeaddrinfo(res->temp_ai); res->temp_ai = NULL; } free(res); } async->os_specific = NULL; } async->hostname = NULL; } /* * Curl_resolver_getsock() is called when someone from the outside world * (using curl_multi_fdset()) wants to get our fd_set setup and we're talking * with ares. The caller must make sure that this function is only called when * we have a working ares channel. * * Returns: sockets-in-use-bitmap */ int Curl_resolver_getsock(struct connectdata *conn, curl_socket_t *socks, int numsocks) { struct timeval maxtime; struct timeval timebuf; struct timeval *timeout; long milli; int max = ares_getsock((ares_channel)conn->data->state.resolver, (ares_socket_t *)socks, numsocks); maxtime.tv_sec = CURL_TIMEOUT_RESOLVE; maxtime.tv_usec = 0; timeout = ares_timeout((ares_channel)conn->data->state.resolver, &maxtime, &timebuf); milli = (timeout->tv_sec * 1000) + (timeout->tv_usec/1000); if(milli == 0) milli += 10; Curl_expire_latest(conn->data, milli, EXPIRE_ARES); return max; } /* * waitperform() * * 1) Ask ares what sockets it currently plays with, then * 2) wait for the timeout period to check for action on ares' sockets. * 3) tell ares to act on all the sockets marked as "with action" * * return number of sockets it worked on */ static int waitperform(struct connectdata *conn, int timeout_ms) { struct Curl_easy *data = conn->data; int nfds; int bitmask; ares_socket_t socks[ARES_GETSOCK_MAXNUM]; struct pollfd pfd[ARES_GETSOCK_MAXNUM]; int i; int num = 0; bitmask = ares_getsock((ares_channel)data->state.resolver, socks, ARES_GETSOCK_MAXNUM); for(i=0; i < ARES_GETSOCK_MAXNUM; i++) { pfd[i].events = 0; pfd[i].revents = 0; if(ARES_GETSOCK_READABLE(bitmask, i)) { pfd[i].fd = socks[i]; pfd[i].events |= POLLRDNORM|POLLIN; } if(ARES_GETSOCK_WRITABLE(bitmask, i)) { pfd[i].fd = socks[i]; pfd[i].events |= POLLWRNORM|POLLOUT; } if(pfd[i].events != 0) num++; else break; } if(num) nfds = Curl_poll(pfd, num, timeout_ms); else nfds = 0; if(!nfds) /* Call ares_process() unconditonally here, even if we simply timed out above, as otherwise the ares name resolve won't timeout! */ ares_process_fd((ares_channel)data->state.resolver, ARES_SOCKET_BAD, ARES_SOCKET_BAD); else { /* move through the descriptors and ask for processing on them */ for(i=0; i < num; i++) ares_process_fd((ares_channel)data->state.resolver, pfd[i].revents & (POLLRDNORM|POLLIN)? pfd[i].fd:ARES_SOCKET_BAD, pfd[i].revents & (POLLWRNORM|POLLOUT)? pfd[i].fd:ARES_SOCKET_BAD); } return nfds; } /* * Curl_resolver_is_resolved() is called repeatedly to check if a previous * name resolve request has completed. It should also make sure to time-out if * the operation seems to take too long. * * Returns normal CURLcode errors. */ CURLcode Curl_resolver_is_resolved(struct connectdata *conn, struct Curl_dns_entry **dns) { struct Curl_easy *data = conn->data; struct ResolverResults *res = (struct ResolverResults *) conn->async.os_specific; CURLcode result = CURLE_OK; *dns = NULL; waitperform(conn, 0); if(res && !res->num_pending) { (void)Curl_addrinfo_callback(conn, res->last_status, res->temp_ai); /* temp_ai ownership is moved to the connection, so we need not free-up them */ res->temp_ai = NULL; if(!conn->async.dns) { failf(data, "Could not resolve: %s (%s)", conn->async.hostname, ares_strerror(conn->async.status)); result = conn->bits.proxy?CURLE_COULDNT_RESOLVE_PROXY: CURLE_COULDNT_RESOLVE_HOST; } else *dns = conn->async.dns; destroy_async_data(&conn->async); } return result; } /* * Curl_resolver_wait_resolv() * * waits for a resolve to finish. This function should be avoided since using * this risk getting the multi interface to "hang". * * If 'entry' is non-NULL, make it point to the resolved dns entry * * Returns CURLE_COULDNT_RESOLVE_HOST if the host was not resolved, and * CURLE_OPERATION_TIMEDOUT if a time-out occurred. */ CURLcode Curl_resolver_wait_resolv(struct connectdata *conn, struct Curl_dns_entry **entry) { CURLcode result = CURLE_OK; struct Curl_easy *data = conn->data; long timeout; struct timeval now = Curl_tvnow(); struct Curl_dns_entry *temp_entry; if(entry) *entry = NULL; /* clear on entry */ timeout = Curl_timeleft(data, &now, TRUE); if(timeout < 0) { /* already expired! */ connclose(conn, "Timed out before name resolve started"); return CURLE_OPERATION_TIMEDOUT; } if(!timeout) timeout = CURL_TIMEOUT_RESOLVE * 1000; /* default name resolve timeout */ /* Wait for the name resolve query to complete. */ while(!result) { struct timeval *tvp, tv, store; long timediff; int itimeout; int timeout_ms; itimeout = (timeout > (long)INT_MAX) ? INT_MAX : (int)timeout; store.tv_sec = itimeout/1000; store.tv_usec = (itimeout%1000)*1000; tvp = ares_timeout((ares_channel)data->state.resolver, &store, &tv); /* use the timeout period ares returned to us above if less than one second is left, otherwise just use 1000ms to make sure the progress callback gets called frequent enough */ if(!tvp->tv_sec) timeout_ms = (int)(tvp->tv_usec/1000); else timeout_ms = 1000; waitperform(conn, timeout_ms); result = Curl_resolver_is_resolved(conn, &temp_entry); if(result || conn->async.done) break; if(Curl_pgrsUpdate(conn)) result = CURLE_ABORTED_BY_CALLBACK; else { struct timeval now2 = Curl_tvnow(); timediff = Curl_tvdiff(now2, now); /* spent time */ timeout -= timediff?timediff:1; /* always deduct at least 1 */ now = now2; /* for next loop */ } if(timeout < 0) result = CURLE_OPERATION_TIMEDOUT; } if(result) /* failure, so we cancel the ares operation */ ares_cancel((ares_channel)data->state.resolver); /* Operation complete, if the lookup was successful we now have the entry in the cache. */ if(entry) *entry = conn->async.dns; if(result) /* close the connection, since we can't return failure here without cleaning up this connection properly. TODO: remove this action from here, it is not a name resolver decision. */ connclose(conn, "c-ares resolve failed"); return result; } /* Connects results to the list */ static void compound_results(struct ResolverResults *res, Curl_addrinfo *ai) { Curl_addrinfo *ai_tail; if(!ai) return; ai_tail = ai; while(ai_tail->ai_next) ai_tail = ai_tail->ai_next; /* Add the new results to the list of old results. */ ai_tail->ai_next = res->temp_ai; res->temp_ai = ai; } /* * ares_query_completed_cb() is the callback that ares will call when * the host query initiated by ares_gethostbyname() from Curl_getaddrinfo(), * when using ares, is completed either successfully or with failure. */ static void query_completed_cb(void *arg, /* (struct connectdata *) */ int status, #ifdef HAVE_CARES_CALLBACK_TIMEOUTS int timeouts, #endif struct hostent *hostent) { struct connectdata *conn = (struct connectdata *)arg; struct ResolverResults *res; #ifdef HAVE_CARES_CALLBACK_TIMEOUTS (void)timeouts; /* ignored */ #endif if(ARES_EDESTRUCTION == status) /* when this ares handle is getting destroyed, the 'arg' pointer may not be valid so only defer it when we know the 'status' says its fine! */ return; res = (struct ResolverResults *)conn->async.os_specific; res->num_pending--; if(CURL_ASYNC_SUCCESS == status) { Curl_addrinfo *ai = Curl_he2ai(hostent, conn->async.port); if(ai) { compound_results(res, ai); } } /* A successful result overwrites any previous error */ if(res->last_status != ARES_SUCCESS) res->last_status = status; } /* * Curl_resolver_getaddrinfo() - when using ares * * Returns name information about the given hostname and port number. If * successful, the 'hostent' is returned and the forth argument will point to * memory we need to free after use. That memory *MUST* be freed with * Curl_freeaddrinfo(), nothing else. */ Curl_addrinfo *Curl_resolver_getaddrinfo(struct connectdata *conn, const char *hostname, int port, int *waitp) { char *bufp; struct Curl_easy *data = conn->data; struct in_addr in; int family = PF_INET; #ifdef ENABLE_IPV6 /* CURLRES_IPV6 */ struct in6_addr in6; #endif /* CURLRES_IPV6 */ *waitp = 0; /* default to synchronous response */ /* First check if this is an IPv4 address string */ if(Curl_inet_pton(AF_INET, hostname, &in) > 0) { /* This is a dotted IP address 123.123.123.123-style */ return Curl_ip2addr(AF_INET, &in, hostname, port); } #ifdef ENABLE_IPV6 /* CURLRES_IPV6 */ /* Otherwise, check if this is an IPv6 address string */ if(Curl_inet_pton (AF_INET6, hostname, &in6) > 0) /* This must be an IPv6 address literal. */ return Curl_ip2addr(AF_INET6, &in6, hostname, port); switch(conn->ip_version) { default: #if ARES_VERSION >= 0x010601 family = PF_UNSPEC; /* supported by c-ares since 1.6.1, so for older c-ares versions this just falls through and defaults to PF_INET */ break; #endif case CURL_IPRESOLVE_V4: family = PF_INET; break; case CURL_IPRESOLVE_V6: family = PF_INET6; break; } #endif /* CURLRES_IPV6 */ bufp = strdup(hostname); if(bufp) { struct ResolverResults *res = NULL; free(conn->async.hostname); conn->async.hostname = bufp; conn->async.port = port; conn->async.done = FALSE; /* not done */ conn->async.status = 0; /* clear */ conn->async.dns = NULL; /* clear */ res = calloc(sizeof(struct ResolverResults), 1); if(!res) { free(conn->async.hostname); conn->async.hostname = NULL; return NULL; } conn->async.os_specific = res; /* initial status - failed */ res->last_status = ARES_ENOTFOUND; #ifdef ENABLE_IPV6 /* CURLRES_IPV6 */ if(family == PF_UNSPEC) { if(Curl_ipv6works()) { res->num_pending = 2; /* areschannel is already setup in the Curl_open() function */ ares_gethostbyname((ares_channel)data->state.resolver, hostname, PF_INET, query_completed_cb, conn); ares_gethostbyname((ares_channel)data->state.resolver, hostname, PF_INET6, query_completed_cb, conn); } else { res->num_pending = 1; /* areschannel is already setup in the Curl_open() function */ ares_gethostbyname((ares_channel)data->state.resolver, hostname, PF_INET, query_completed_cb, conn); } } else #endif /* CURLRES_IPV6 */ { res->num_pending = 1; /* areschannel is already setup in the Curl_open() function */ ares_gethostbyname((ares_channel)data->state.resolver, hostname, family, query_completed_cb, conn); } *waitp = 1; /* expect asynchronous response */ } return NULL; /* no struct yet */ } CURLcode Curl_set_dns_servers(struct Curl_easy *data, char *servers) { CURLcode result = CURLE_NOT_BUILT_IN; int ares_result; /* If server is NULL or empty, this would purge all DNS servers * from ares library, which will cause any and all queries to fail. * So, just return OK if none are configured and don't actually make * any changes to c-ares. This lets c-ares use it's defaults, which * it gets from the OS (for instance from /etc/resolv.conf on Linux). */ if(!(servers && servers[0])) return CURLE_OK; #if (ARES_VERSION >= 0x010704) ares_result = ares_set_servers_csv(data->state.resolver, servers); switch(ares_result) { case ARES_SUCCESS: result = CURLE_OK; break; case ARES_ENOMEM: result = CURLE_OUT_OF_MEMORY; break; case ARES_ENOTINITIALIZED: case ARES_ENODATA: case ARES_EBADSTR: default: result = CURLE_BAD_FUNCTION_ARGUMENT; break; } #else /* too old c-ares version! */ (void)data; (void)(ares_result); #endif return result; } CURLcode Curl_set_dns_interface(struct Curl_easy *data, const char *interf) { #if (ARES_VERSION >= 0x010704) if(!interf) interf = ""; ares_set_local_dev((ares_channel)data->state.resolver, interf); return CURLE_OK; #else /* c-ares version too old! */ (void)data; (void)interf; return CURLE_NOT_BUILT_IN; #endif } CURLcode Curl_set_dns_local_ip4(struct Curl_easy *data, const char *local_ip4) { #if (ARES_VERSION >= 0x010704) struct in_addr a4; if((!local_ip4) || (local_ip4[0] == 0)) { a4.s_addr = 0; /* disabled: do not bind to a specific address */ } else { if(Curl_inet_pton(AF_INET, local_ip4, &a4) != 1) { return CURLE_BAD_FUNCTION_ARGUMENT; } } ares_set_local_ip4((ares_channel)data->state.resolver, ntohl(a4.s_addr)); return CURLE_OK; #else /* c-ares version too old! */ (void)data; (void)local_ip4; return CURLE_NOT_BUILT_IN; #endif } CURLcode Curl_set_dns_local_ip6(struct Curl_easy *data, const char *local_ip6) { #if (ARES_VERSION >= 0x010704) && defined(ENABLE_IPV6) unsigned char a6[INET6_ADDRSTRLEN]; if((!local_ip6) || (local_ip6[0] == 0)) { /* disabled: do not bind to a specific address */ memset(a6, 0, sizeof(a6)); } else { if(Curl_inet_pton(AF_INET6, local_ip6, a6) != 1) { return CURLE_BAD_FUNCTION_ARGUMENT; } } ares_set_local_ip6((ares_channel)data->state.resolver, a6); return CURLE_OK; #else /* c-ares version too old! */ (void)data; (void)local_ip6; return CURLE_NOT_BUILT_IN; #endif } #endif /* CURLRES_ARES */