- ares_gethostbyname() now accepts 'AF_UNSPEC' as a family for resolving (a2256e89) · Commits · CYBER - Cyber Security / TS 103 523 MSP / TLMSP / TLMSP curl

ares/CHANGES

+5 −0

Original line number	Diff line number	Diff line
		Changelog for the c-ares project

		* January 31 2009 (Daniel Stenberg)
		- ares_gethostbyname() now accepts 'AF_UNSPEC' as a family for resolving
		either AF_INET6 or AF_INET. It works by accepting any of the looksups in the
		hosts file, and it resolves the AAAA field with a fallback to A.

		* January 14 2009 (Daniel Stenberg)
		- ares.h no longer uses the HAVE_STRUCT_IN6_ADDR define check, but instead it
		now declares the private struct ares_in6_addr for all systems instead of

ares/RELEASE-NOTES

+4 −2

Original line number	Diff line number	Diff line
		@@ -2,8 +2,10 @@ This is what's new and changed in the c-ares 1.6.1 release:

		Changed:

		o in6_addr is not used in ares.h anymore, but a private ares_in6_addr is instead
		declared and used
		o in6_addr is not used in ares.h anymore, but a private ares_in6_addr is
		instead declared and used
		p ares_gethostbyname() now supports 'AF_UNSPEC' as a family for resolving
		either AF_INET6 or AF_INET

		Fixed:

ares/ares__get_hostent.c

+14 −10

Original line number	Diff line number	Diff line
		@@ -69,16 +69,20 @@ int ares__get_hostent(FILE fp, int family, struct hostent *host)
		addr.s_addr = inet_addr(line);
		if (addr.s_addr == INADDR_NONE)
		{
		if (ares_inet_pton(AF_INET6, line, &addr6) > 0)
		{
		if (family != AF_INET6)
		continue;
		/* It wasn't an AF_INET dotted address, then AF_UNSPEC and AF_INET6
		families are subject for this further check */
		if ((family != AF_INET) &&
		(ares_inet_pton(AF_INET6, line, &addr6) > 0)) {
		addrlen = sizeof(struct in6_addr);
		family = AF_INET6;
		}
		else
		continue;
		}
		else if (family == AF_UNSPEC)
		family = AF_INET; /* now confirmed! */
		else if (family != AF_INET)
		/* unknown, keep moving */
		continue;

		/* Get the canonical hostname. */

ares/ares_gethostbyname.c

+54 −41

Original line number	Diff line number	Diff line
		@@ -61,7 +61,8 @@ struct host_query {
		char *name;
		ares_host_callback callback;
		void *arg;
		int family;
		int sent_family; /* this family is what was is being used */
		int want_family; /* this family is what is asked for in the API */
		const char *remaining_lookups;
		int timeouts;
		};
		@@ -71,26 +72,31 @@ static void host_callback(void *arg, int status, int timeouts,
		unsigned char *abuf, int alen);
		static void end_hquery(struct host_query *hquery, int status,
		struct hostent *host);
		static int fake_hostent(const char *name, int family, ares_host_callback callback,
		void *arg);
		static int fake_hostent(const char *name, int family,
		ares_host_callback callback, void *arg);
		static int file_lookup(const char name, int family, struct hostent *host);
		static void sort_addresses(struct hostent host, const struct apattern sortlist,
		int nsort);
		static void sort6_addresses(struct hostent host, const struct apattern sortlist,
		int nsort);
		static int get_address_index(const struct in_addr addr, const struct apattern sortlist,
		int nsort);
		static int get6_address_index(const struct in6_addr addr, const struct apattern sortlist,
		int nsort);
		static void sort_addresses(struct hostent *host,
		const struct apattern *sortlist, int nsort);
		static void sort6_addresses(struct hostent *host,
		const struct apattern *sortlist, int nsort);
		static int get_address_index(const struct in_addr *addr,
		const struct apattern *sortlist, int nsort);
		static int get6_address_index(const struct in6_addr *addr,
		const struct apattern *sortlist, int nsort);

		void ares_gethostbyname(ares_channel channel, const char *name, int family,
		ares_host_callback callback, void *arg)
		{
		struct host_query *hquery;

		/* Right now we only know how to look up Internet addresses. */
		if (family != AF_INET && family != AF_INET6)
		{
		/* Right now we only know how to look up Internet addresses - and unspec
		means try both basically. */
		switch (family) {
		case AF_INET:
		case AF_INET6:
		case AF_UNSPEC:
		break;
		default:
		callback(arg, ARES_ENOTIMP, 0, NULL);
		return;
		}
		@@ -107,9 +113,9 @@ void ares_gethostbyname(ares_channel channel, const char *name, int family,
		}
		hquery->channel = channel;
		hquery->name = strdup(name);
		hquery->family = family;
		if (!hquery->name)
		{
		hquery->want_family = family;
		hquery->sent_family = -1; /* nothing is sent yet */
		if (!hquery->name) {
		free(hquery);
		callback(arg, ARES_ENOMEM, 0, NULL);
		return;
		@@ -136,17 +142,23 @@ static void next_lookup(struct host_query *hquery, int status_code)
		case 'b':
		/* DNS lookup */
		hquery->remaining_lookups = p + 1;
		if (hquery->family == AF_INET6)
		if ((hquery->want_family == AF_INET6) \|\|
		(hquery->want_family == AF_UNSPEC)) {
		/* if inet6 or unspec, start out with AAAA */
		hquery->sent_family = AF_INET6;
		ares_search(hquery->channel, hquery->name, C_IN, T_AAAA,
		host_callback, hquery);
		else
		}
		else {
		hquery->sent_family = AF_INET;
		ares_search(hquery->channel, hquery->name, C_IN, T_A, host_callback,
		hquery);
		}
		return;

		case 'f':
		/* Host file lookup */
		status = file_lookup(hquery->name, hquery->family, &host);
		status = file_lookup(hquery->name, hquery->want_family, &host);

		/* this status check below previously checked for !ARES_ENOTFOUND,
		but we should not assume that this single error code is the one
		@@ -173,22 +185,22 @@ static void host_callback(void *arg, int status, int timeouts,
		hquery->timeouts += timeouts;
		if (status == ARES_SUCCESS)
		{
		if (hquery->family == AF_INET)
		if (hquery->sent_family == AF_INET)
		{
		status = ares_parse_a_reply(abuf, alen, &host, NULL, NULL);
		if (host && channel->nsort)
		sort_addresses(host, channel->sortlist, channel->nsort);
		}
		else if (hquery->family == AF_INET6)
		else if (hquery->sent_family == AF_INET6)
		{
		status = ares_parse_aaaa_reply(abuf, alen, &host, NULL, NULL);
		if (status == ARES_ENODATA)
		{
		if (status == ARES_ENODATA) {
		/* The query returned something (e.g. CNAME) but there were no
		AAAA records. Try looking up A instead. */
		hquery->family = AF_INET;
		ares_search(hquery->channel, hquery->name, C_IN, T_A, host_callback,
		hquery);
		AAAA records. Try looking up A instead. We should possibly
		limit this attempt-next logic to AF_UNSPEC lookups only. */
		hquery->sent_family = AF_INET;
		ares_search(hquery->channel, hquery->name, C_IN, T_A,
		host_callback, hquery);
		return;
		}
		if (host && channel->nsort)
		@@ -196,10 +208,11 @@ static void host_callback(void *arg, int status, int timeouts,
		}
		end_hquery(hquery, status, host);
		}
		else if (status == ARES_ENODATA && hquery->family == AF_INET6)
		else if (status == ARES_ENODATA && hquery->sent_family == AF_INET6)
		{
		/* There was no AAAA. Now lookup an A */
		hquery->family = AF_INET;
		/* There was no AAAA. Now lookup an A. We should possibly limit this
		attempt-next logic to AF_UNSPEC lookups only. */
		hquery->sent_family = AF_INET;
		ares_search(hquery->channel, hquery->name, C_IN, T_A, host_callback,
		hquery);
		}