diff options
Diffstat (limited to 'deps/cares/src/ares_init.c')
| -rw-r--r-- | deps/cares/src/ares_init.c | 446 |
1 files changed, 407 insertions, 39 deletions
diff --git a/deps/cares/src/ares_init.c b/deps/cares/src/ares_init.c index f557947aa1..dbc67ed441 100644 --- a/deps/cares/src/ares_init.c +++ b/deps/cares/src/ares_init.c @@ -84,7 +84,7 @@ static int config_sortlist(struct apattern **sortlist, int *nsort, const char *str); static int sortlist_alloc(struct apattern **sortlist, int *nsort, struct apattern *pat); -static int ip_addr(const char *s, ssize_t len, struct in_addr *addr); +static int ip_addr(const char *s, ares_ssize_t len, struct in_addr *addr); static void natural_mask(struct apattern *pat); #if !defined(WIN32) && !defined(WATT32) && \ !defined(ANDROID) && !defined(__ANDROID__) && !defined(CARES_USE_LIBRESOLV) @@ -166,6 +166,8 @@ int ares_init_options(ares_channel *channelptr, struct ares_options *options, channel->sock_create_cb_data = NULL; channel->sock_config_cb = NULL; channel->sock_config_cb_data = NULL; + channel->sock_funcs = NULL; + channel->sock_func_cb_data = NULL; channel->last_server = 0; channel->last_timeout_processed = (time_t)now.tv_sec; @@ -292,6 +294,8 @@ int ares_dup(ares_channel *dest, ares_channel src) (*dest)->sock_create_cb_data = src->sock_create_cb_data; (*dest)->sock_config_cb = src->sock_config_cb; (*dest)->sock_config_cb_data = src->sock_config_cb_data; + (*dest)->sock_funcs = src->sock_funcs; + (*dest)->sock_func_cb_data = src->sock_func_cb_data; strncpy((*dest)->local_dev_name, src->local_dev_name, sizeof(src->local_dev_name)); @@ -828,6 +832,24 @@ static int get_DNS_Registry(char **outptr) return 1; } +static void commanjoin(char** dst, const char* const src, const size_t len) +{ + char *newbuf; + size_t newsize; + + /* 1 for terminating 0 and 2 for , and terminating 0 */ + newsize = len + (*dst ? (strlen(*dst) + 2) : 1); + newbuf = ares_realloc(*dst, newsize); + if (!newbuf) + return; + if (*dst == NULL) + *newbuf = '\0'; + *dst = newbuf; + if (strlen(*dst) != 0) + strcat(*dst, ","); + strncat(*dst, src, len); +} + /* * commajoin() * @@ -835,24 +857,7 @@ static int get_DNS_Registry(char **outptr) */ static void commajoin(char **dst, const char *src) { - char *tmp; - - if (*dst) - { - tmp = ares_malloc(strlen(*dst) + strlen(src) + 2); - if (!tmp) - return; - sprintf(tmp, "%s,%s", *dst, src); - ares_free(*dst); - *dst = tmp; - } - else - { - *dst = ares_malloc(strlen(src) + 1); - if (!*dst) - return; - strcpy(*dst, src); - } + commanjoin(dst, src, strlen(src)); } /* @@ -939,6 +944,116 @@ done: return 1; } +static BOOL ares_IsWindowsVistaOrGreater(void) +{ + OSVERSIONINFO vinfo; + memset(&vinfo, 0, sizeof(vinfo)); + vinfo.dwOSVersionInfoSize = sizeof(vinfo); + if (!GetVersionEx(&vinfo) || vinfo.dwMajorVersion < 6) + return FALSE; + return TRUE; +} + +/* A structure to hold the string form of IPv4 and IPv6 addresses so we can + * sort them by a metric. + */ +typedef struct +{ + /* The metric we sort them by. */ + ULONG metric; + + /* Room enough for the string form of any IPv4 or IPv6 address that + * ares_inet_ntop() will create. Based on the existing c-ares practice. + */ + char text[sizeof("ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255")]; +} Address; + +/* Sort Address values \a left and \a right by metric, returning the usual + * indicators for qsort(). + */ +static int compareAddresses(const void *arg1, + const void *arg2) +{ + const Address * const left = arg1; + const Address * const right = arg2; + if(left->metric < right->metric) return -1; + if(left->metric > right->metric) return 1; + return 0; +} + +/* There can be multiple routes to "the Internet". And there can be different + * DNS servers associated with each of the interfaces that offer those routes. + * We have to assume that any DNS server can serve any request. But, some DNS + * servers may only respond if requested over their associated interface. But + * we also want to use "the preferred route to the Internet" whenever possible + * (and not use DNS servers on a non-preferred route even by forcing request + * to go out on the associated non-preferred interface). i.e. We want to use + * the DNS servers associated with the same interface that we would use to + * make a general request to anything else. + * + * But, Windows won't sort the DNS servers by the metrics associated with the + * routes and interfaces _even_ though it obviously sends IP packets based on + * those same routes and metrics. So, we must do it ourselves. + * + * So, we sort the DNS servers by the same metric values used to determine how + * an outgoing IP packet will go, thus effectively using the DNS servers + * associated with the interface that the DNS requests themselves will + * travel. This gives us optimal routing and avoids issues where DNS servers + * won't respond to requests that don't arrive via some specific subnetwork + * (and thus some specific interface). + * + * This function computes the metric we use to sort. On the interface + * identified by \a luid, it determines the best route to \a dest and combines + * that route's metric with \a interfaceMetric to compute a metric for the + * destination address on that interface. This metric can be used as a weight + * to sort the DNS server addresses associated with each interface (lower is + * better). + * + * Note that by restricting the route search to the specific interface with + * which the DNS servers are associated, this function asks the question "What + * is the metric for sending IP packets to this DNS server?" which allows us + * to sort the DNS servers correctly. + */ +static ULONG getBestRouteMetric(IF_LUID * const luid, /* Can't be const :( */ + const SOCKADDR_INET * const dest, + const ULONG interfaceMetric) +{ + /* On this interface, get the best route to that destination. */ + MIB_IPFORWARD_ROW2 row; + SOCKADDR_INET ignored; + if(!ares_fpGetBestRoute2 || + ares_fpGetBestRoute2(/* The interface to use. The index is ignored since we are + * passing a LUID. + */ + luid, 0, + /* No specific source address. */ + NULL, + /* Our destination address. */ + dest, + /* No options. */ + 0, + /* The route row. */ + &row, + /* The best source address, which we don't need. */ + &ignored) != NO_ERROR + /* If the metric is "unused" (-1) or too large for us to add the two + * metrics, use the worst possible, thus sorting this last. + */ + || row.Metric == (ULONG)-1 + || row.Metric > ((ULONG)-1) - interfaceMetric) { + /* Return the worst possible metric. */ + return (ULONG)-1; + } + + /* Return the metric value from that row, plus the interface metric. + * + * See + * http://msdn.microsoft.com/en-us/library/windows/desktop/aa814494(v=vs.85).aspx + * which describes the combination as a "sum". + */ + return row.Metric + interfaceMetric; +} + /* * get_DNS_AdaptersAddresses() * @@ -965,14 +1080,19 @@ static int get_DNS_AdaptersAddresses(char **outptr) int trying = IPAA_MAX_TRIES; int res; + /* The capacity of addresses, in elements. */ + size_t addressesSize; + /* The number of elements in addresses. */ + size_t addressesIndex = 0; + /* The addresses we will sort. */ + Address *addresses; + union { struct sockaddr *sa; struct sockaddr_in *sa4; struct sockaddr_in6 *sa6; } namesrvr; - char txtaddr[sizeof("ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255")]; - *outptr = NULL; /* Verify run-time availability of GetAdaptersAddresses() */ @@ -983,6 +1103,17 @@ static int get_DNS_AdaptersAddresses(char **outptr) if (!ipaa) return 0; + /* Start with enough room for a few DNS server addresses and we'll grow it + * as we encounter more. + */ + addressesSize = 4; + addresses = (Address*)ares_malloc(sizeof(Address) * addressesSize); + if(addresses == NULL) { + /* We need room for at least some addresses to function. */ + ares_free(ipaa); + return 0; + } + /* Usually this call suceeds with initial buffer size */ res = (*ares_fpGetAdaptersAddresses) (AF_UNSPEC, AddrFlags, NULL, ipaa, &ReqBufsz); @@ -1012,6 +1143,12 @@ static int get_DNS_AdaptersAddresses(char **outptr) if(ipaaEntry->OperStatus != IfOperStatusUp) continue; + /* For each interface, find any associated DNS servers as IPv4 or IPv6 + * addresses. For each found address, find the best route to that DNS + * server address _on_ _that_ _interface_ (at this moment in time) and + * compute the resulting total metric, just as Windows routing will do. + * Then, sort all the addresses found by the metric. + */ for (ipaDNSAddr = ipaaEntry->FirstDnsServerAddress; ipaDNSAddr; ipaDNSAddr = ipaDNSAddr->Next) @@ -1023,35 +1160,117 @@ static int get_DNS_AdaptersAddresses(char **outptr) if ((namesrvr.sa4->sin_addr.S_un.S_addr == INADDR_ANY) || (namesrvr.sa4->sin_addr.S_un.S_addr == INADDR_NONE)) continue; + + /* Allocate room for another address, if necessary, else skip. */ + if(addressesIndex == addressesSize) { + const size_t newSize = addressesSize + 4; + Address * const newMem = + (Address*)ares_realloc(addresses, sizeof(Address) * newSize); + if(newMem == NULL) { + continue; + } + addresses = newMem; + addressesSize = newSize; + } + + /* Vista required for Luid or Ipv4Metric */ + if (ares_IsWindowsVistaOrGreater()) + { + /* Save the address as the next element in addresses. */ + addresses[addressesIndex].metric = + getBestRouteMetric(&ipaaEntry->Luid, + (SOCKADDR_INET*)(namesrvr.sa), + ipaaEntry->Ipv4Metric); + } + else + { + addresses[addressesIndex].metric = -1; + } + if (! ares_inet_ntop(AF_INET, &namesrvr.sa4->sin_addr, - txtaddr, sizeof(txtaddr))) + addresses[addressesIndex].text, + sizeof(addresses[0].text))) { continue; + } + ++addressesIndex; } else if (namesrvr.sa->sa_family == AF_INET6) { if (memcmp(&namesrvr.sa6->sin6_addr, &ares_in6addr_any, sizeof(namesrvr.sa6->sin6_addr)) == 0) continue; + + /* Allocate room for another address, if necessary, else skip. */ + if(addressesIndex == addressesSize) { + const size_t newSize = addressesSize + 4; + Address * const newMem = + (Address*)ares_realloc(addresses, sizeof(Address) * newSize); + if(newMem == NULL) { + continue; + } + addresses = newMem; + addressesSize = newSize; + } + + /* Vista required for Luid or Ipv4Metric */ + if (ares_IsWindowsVistaOrGreater()) + { + /* Save the address as the next element in addresses. */ + addresses[addressesIndex].metric = + getBestRouteMetric(&ipaaEntry->Luid, + (SOCKADDR_INET*)(namesrvr.sa), + ipaaEntry->Ipv6Metric); + } + else + { + addresses[addressesIndex].metric = -1; + } + if (! ares_inet_ntop(AF_INET6, &namesrvr.sa6->sin6_addr, - txtaddr, sizeof(txtaddr))) + addresses[addressesIndex].text, + sizeof(addresses[0].text))) { continue; + } + ++addressesIndex; } - else + else { + /* Skip non-IPv4/IPv6 addresses completely. */ continue; + } + } + } - commajoin(outptr, txtaddr); + /* Sort all of the textual addresses by their metric. */ + qsort(addresses, addressesIndex, sizeof(*addresses), compareAddresses); - if (!*outptr) - goto done; + /* Join them all into a single string, removing duplicates. */ + { + size_t i; + for(i = 0; i < addressesIndex; ++i) { + size_t j; + /* Look for this address text appearing previously in the results. */ + for(j = 0; j < i; ++j) { + if(strcmp(addresses[j].text, addresses[i].text) == 0) { + break; + } + } + /* Iff we didn't emit this address already, emit it now. */ + if(j == i) { + /* Add that to outptr (if we can). */ + commajoin(outptr, addresses[i].text); + } } } done: + ares_free(addresses); + if (ipaa) ares_free(ipaa); - if (!*outptr) + if (!*outptr) { return 0; + } return 1; } @@ -1072,23 +1291,158 @@ done: */ static int get_DNS_Windows(char **outptr) { - /* - Use GetNetworkParams First in case of - multiple adapter is enabled on this machine. - GetAdaptersAddresses will retrive dummy dns servers. - That will slowing DNS lookup. - */ - /* Try using IP helper API GetNetworkParams() */ - if (get_DNS_NetworkParams(outptr)) + /* Try using IP helper API GetAdaptersAddresses(). IPv4 + IPv6, also sorts + * DNS servers by interface route metrics to try to use the best DNS server. */ + if (get_DNS_AdaptersAddresses(outptr)) return 1; - /* Try using IP helper API GetAdaptersAddresses() */ - if (get_DNS_AdaptersAddresses(outptr)) + /* Try using IP helper API GetNetworkParams(). IPv4 only. */ + if (get_DNS_NetworkParams(outptr)) return 1; /* Fall-back to registry information */ return get_DNS_Registry(outptr); } + +static void replace_comma_by_space(char* str) +{ + /* replace ',' by ' ' to coincide with resolv.conf search parameter */ + char *p; + for (p = str; *p != '\0'; p++) + { + if (*p == ',') + *p = ' '; + } +} + +/* Search if 'suffix' is containted in the 'searchlist'. Returns true if yes, + * otherwise false. 'searchlist' is a comma separated list of domain suffixes, + * 'suffix' is one domain suffix, 'len' is the length of 'suffix'. + * The search ignores case. E.g.: + * contains_suffix("abc.def,ghi.jkl", "ghi.JKL") returns true */ +static bool contains_suffix(const char* const searchlist, + const char* const suffix, const size_t len) +{ + const char* beg = searchlist; + const char* end; + if (!*suffix) + return true; + for (;;) + { + while (*beg && (ISSPACE(*beg) || (*beg == ','))) + ++beg; + if (!*beg) + return false; + end = beg; + while (*end && !ISSPACE(*end) && (*end != ',')) + ++end; + if (len == (end - beg) && !strnicmp(beg, suffix, len)) + return true; + beg = end; + } +} + +/* advances list to the next suffix within a comma separated search list. + * len is the length of the next suffix. */ +static size_t next_suffix(const char** list, const size_t advance) +{ + const char* beg = *list + advance; + const char* end; + while (*beg && (ISSPACE(*beg) || (*beg == ','))) + ++beg; + end = beg; + while (*end && !ISSPACE(*end) && (*end != ',')) + ++end; + *list = beg; + return end - beg; +} + +/* + * get_SuffixList_Windows() + * + * Reads the "DNS Suffix Search List" from registry and writes the list items + * whitespace separated to outptr. If the Search List is empty, the + * "Primary Dns Suffix" is written to outptr. + * + * Returns 0 and nullifies *outptr upon inability to return the suffix list. + * + * Returns 1 and sets *outptr when returning a dynamically allocated string. + * + * Implementation supports Windows Server 2003 and newer + */ +static int get_SuffixList_Windows(char **outptr) +{ + HKEY hKey, hKeyEnum; + char keyName[256]; + DWORD keyNameBuffSize; + DWORD keyIdx = 0; + char *p = NULL; + char *pp; + size_t len = 0; + + *outptr = NULL; + + if (ares__getplatform() != WIN_NT) + return 0; + + /* 1. Global DNS Suffix Search List */ + if (RegOpenKeyEx(HKEY_LOCAL_MACHINE, WIN_NS_NT_KEY, 0, + KEY_READ, &hKey) == ERROR_SUCCESS) + { + if (get_REG_SZ(hKey, SEARCHLIST_KEY, outptr)) + replace_comma_by_space(*outptr); + RegCloseKey(hKey); + if (*outptr) + return 1; + } + + /* 2. Connection Specific Search List composed of: + * a. Primary DNS Suffix */ + if (RegOpenKeyEx(HKEY_LOCAL_MACHINE, WIN_DNSCLIENT, 0, + KEY_READ, &hKey) == ERROR_SUCCESS) + { + get_REG_SZ(hKey, PRIMARYDNSSUFFIX_KEY, outptr); + RegCloseKey(hKey); + } + if (!*outptr) + return 0; + + /* b. Interface SearchList, Domain, DhcpDomain */ + if (!RegOpenKeyEx(HKEY_LOCAL_MACHINE, WIN_NS_NT_KEY "\\" INTERFACES_KEY, 0, + KEY_READ, &hKey) == ERROR_SUCCESS) + return 0; + for(;;) + { + keyNameBuffSize = sizeof(keyName); + if (RegEnumKeyEx(hKey, keyIdx++, keyName, &keyNameBuffSize, + 0, NULL, NULL, NULL) + != ERROR_SUCCESS) + break; + if (RegOpenKeyEx(hKey, keyName, 0, KEY_QUERY_VALUE, &hKeyEnum) + != ERROR_SUCCESS) + continue; + if (get_REG_SZ(hKeyEnum, SEARCHLIST_KEY, &p) || + get_REG_SZ(hKeyEnum, DOMAIN_KEY, &p) || + get_REG_SZ(hKeyEnum, DHCPDOMAIN_KEY, &p)) + { + /* p can be comma separated (SearchList) */ + pp = p; + while (len = next_suffix(&pp, len)) + { + if (!contains_suffix(*outptr, pp, len)) + commanjoin(outptr, pp, len); + } + ares_free(p); + p = NULL; + } + RegCloseKey(hKeyEnum); + } + RegCloseKey(hKey); + if (*outptr) + replace_comma_by_space(*outptr); + return *outptr != NULL; +} + #endif static int init_by_resolv_conf(ares_channel channel) @@ -1112,6 +1466,12 @@ static int init_by_resolv_conf(ares_channel channel) ares_free(line); } + if (channel->ndomains == -1 && get_SuffixList_Windows(&line)) + { + status = set_search(channel, line); + ares_free(line); + } + if (status == ARES_SUCCESS) status = ARES_EOF; else @@ -1950,7 +2310,7 @@ static char *try_config(char *s, const char *opt, char scc) } #endif /* !WIN32 & !WATT32 & !ANDROID & !__ANDROID__ */ -static int ip_addr(const char *ipbuf, ssize_t len, struct in_addr *addr) +static int ip_addr(const char *ipbuf, ares_ssize_t len, struct in_addr *addr) { /* Four octets and three periods yields at most 15 characters. */ @@ -2103,6 +2463,14 @@ void ares_set_socket_configure_callback(ares_channel channel, channel->sock_config_cb_data = data; } +void ares_set_socket_functions(ares_channel channel, + const struct ares_socket_functions * funcs, + void *data) +{ + channel->sock_funcs = funcs; + channel->sock_func_cb_data = data; +} + int ares_set_sortlist(ares_channel channel, const char *sortstr) { int nsort = 0; |