added ares_process_fd() to allow applications to ask for processing on (67027396) · Commits · CYBER - Cyber Security / TS 103 523 MSP / TLMSP / TLMSP curl

ares/CHANGES

+10 −0

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

		* May 30 2007

		- Daniel S added ares_process_fd() to allow applications to ask for processing
		on specific sockets and thus avoiding select() and associated
		functions/macros. This function will be used by upcoming libcurl releases
		for this very reason. It also made me export the ares_socket_t type in the
		public ares.h header file, since ares_process_fd() uses that type for two of
		the arguments.

		* May 25 2007

		- Ravi Pratap fixed a flaw in the init_by_resolv_conf() function for windows
		that could cause it to return a bad return code.

ares/ares.h

+18 −0

Original line number	Diff line number	Diff line
		@@ -136,6 +136,22 @@ extern "C" {
		#define ARES_GETSOCK_WRITABLE(bits,num) (bits & (1 << ((num) + \
		ARES_GETSOCK_MAXNUM)))


		/*
		* Typedef our socket type
		*/

		#ifndef ares_socket_typedef
		#ifdef WIN32
		typedef SOCKET ares_socket_t;
		#define ARES_SOCKET_BAD INVALID_SOCKET
		#else
		typedef int ares_socket_t;
		#define ARES_SOCKET_BAD -1
		#endif
		#define ares_socket_typedef
		#endif /* ares_socket_typedef */

		#ifdef WIN32
		typedef void (ares_sock_state_cb)(void data,
		SOCKET socket,
		@@ -200,6 +216,8 @@ int ares_getsock(ares_channel channel, int *socks, int numsocks);
		struct timeval ares_timeout(ares_channel channel, struct timeval maxtv,
		struct timeval *tv);
		void ares_process(ares_channel channel, fd_set read_fds, fd_set write_fds);
		void ares_process_fd(ares_channel channel, ares_socket_t read_fd,
		ares_socket_t write_fd);

		int ares_mkquery(const char *name, int dnsclass, int type, unsigned short id,
		int rd, unsigned char *buf, int buflen);

ares/ares_process.3

+13 −8

Original line number	Diff line number	Diff line
		@@ -24,16 +24,16 @@ ares_process \- Process events for name resolution
		.B void ares_process(ares_channel \fIchannel\fP, fd_set *\fIread_fds\fP,
		.B fd_set *\fIwrite_fds\fP)
		.fi
		.PP
		.B void ares_process_fd(ares_channel \fIchannel\fP,
		.B ares_socket_t \fIread_fd\fP,
		.B ares_socket_t \fIwrite_fd\fP)
		.fi
		.SH DESCRIPTION
		The
		.B ares_process
		function handles input/output events and timeouts associated with
		queries pending on the name service channel identified by
		The \fBares_process(3)\fP function handles input/output events and timeouts
		associated with queries pending on the name service channel identified by
		.IR channel .
		The file descriptor sets pointed to by
		.I read_fds
		and
		.I write_fds
		The file descriptor sets pointed to by \fIread_fds\fP and \fIwrite_fds\fP
		should have file descriptors set in them according to whether the file
		descriptors specified by \fIares_fds(3)\fP are ready for reading and writing.
		(The easiest way to determine this information is to invoke
		@@ -44,6 +44,11 @@ The
		.B ares_process
		function will invoke callbacks for pending queries if they complete
		successfully or fail.

		\fBares_process_fd(3)\fP works the same way but acts and operates only on the
		specific file descriptors (sockets) you pass in to the function. Use
		ARES_SOCKET_BAD for "no action". This function is of course provided to allow
		users of c-ares to void select() in their applications and within c-ares.
		.SS EXAMPLE
		The following code fragment waits for all pending queries on a channel
		to complete:

ares/ares_process.c

+76 −16

Original line number	Diff line number	Diff line
		@@ -56,10 +56,11 @@

		static int try_again(int errnum);
		static void write_tcp_data(ares_channel channel, fd_set *write_fds,
		time_t now);
		static void read_tcp_data(ares_channel channel, fd_set *read_fds, time_t now);
		ares_socket_t write_fd, time_t now);
		static void read_tcp_data(ares_channel channel, fd_set *read_fds,
		ares_socket_t read_fd, time_t now);
		static void read_udp_packets(ares_channel channel, fd_set *read_fds,
		time_t now);
		ares_socket_t read_fd, time_t now);
		static void process_timeouts(ares_channel channel, time_t now);
		static void process_answer(ares_channel channel, unsigned char *abuf,
		int alen, int whichserver, int tcp, int now);
		@@ -80,12 +81,30 @@ void ares_process(ares_channel channel, fd_set read_fds, fd_set write_fds)
		time_t now;

		time(&now);
		write_tcp_data(channel, write_fds, now);
		read_tcp_data(channel, read_fds, now);
		read_udp_packets(channel, read_fds, now);
		write_tcp_data(channel, write_fds, ARES_SOCKET_BAD, now);
		read_tcp_data(channel, read_fds, ARES_SOCKET_BAD, now);
		read_udp_packets(channel, read_fds, ARES_SOCKET_BAD, now);
		process_timeouts(channel, now);
		}

		/* Something interesting happened on the wire, or there was a timeout.
		* See what's up and respond accordingly.
		*/
		void ares_process_fd(ares_channel channel,
		ares_socket_t read_fd, /* use ARES_SOCKET_BAD or valid
		file descriptors */
		ares_socket_t write_fd)
		{
		time_t now;

		time(&now);
		write_tcp_data(channel, NULL, write_fd, now);
		read_tcp_data(channel, NULL, read_fd, now);
		read_udp_packets(channel, NULL, read_fd, now);
		process_timeouts(channel, now);
		}


		/* Return 1 if the specified error number describes a readiness error, or 0
		* otherwise. This is mostly for HP-UX, which could return EAGAIN or
		* EWOULDBLOCK. See this man page
		@@ -114,7 +133,10 @@ static int try_again(int errnum)
		/* If any TCP sockets select true for writing, write out queued data
		* we have for them.
		*/
		static void write_tcp_data(ares_channel channel, fd_set *write_fds, time_t now)
		static void write_tcp_data(ares_channel channel,
		fd_set *write_fds,
		ares_socket_t write_fd,
		time_t now)
		{
		struct server_state *server;
		struct send_request *sendreq;
		@@ -124,13 +146,26 @@ static void write_tcp_data(ares_channel channel, fd_set *write_fds, time_t now)
		ssize_t wcount;
		size_t n;

		if(!write_fds && (write_fd == ARES_SOCKET_BAD))
		/* no possible action */
		return;

		for (i = 0; i < channel->nservers; i++)
		{
		/* Make sure server has data to send and is selected in write_fds. */
		/* Make sure server has data to send and is selected in write_fds or
		write_fd. */
		server = &channel->servers[i];
		if (!server->qhead \|\| server->tcp_socket == ARES_SOCKET_BAD
		\|\| !FD_ISSET(server->tcp_socket, write_fds))
		if (!server->qhead \|\| server->tcp_socket == ARES_SOCKET_BAD)
		continue;

		if(write_fds) {
		if(!FD_ISSET(server->tcp_socket, write_fds))
		continue;
		}
		else {
		if(server->tcp_socket != write_fd)
		continue;
		}

		/* Count the number of send queue items. */
		n = 0;
		@@ -218,20 +253,33 @@ static void write_tcp_data(ares_channel channel, fd_set *write_fds, time_t now)
		* allocate a buffer if we finish reading the length word, and process
		* a packet if we finish reading one.
		*/
		static void read_tcp_data(ares_channel channel, fd_set *read_fds, time_t now)
		static void read_tcp_data(ares_channel channel, fd_set *read_fds,
		ares_socket_t read_fd, time_t now)
		{
		struct server_state *server;
		int i;
		ssize_t count;

		if(!read_fds && (read_fd == ARES_SOCKET_BAD))
		/* no possible action */
		return;

		for (i = 0; i < channel->nservers; i++)
		{
		/* Make sure the server has a socket and is selected in read_fds. */
		server = &channel->servers[i];
		if (server->tcp_socket == ARES_SOCKET_BAD \|\|
		!FD_ISSET(server->tcp_socket, read_fds))
		if (server->tcp_socket == ARES_SOCKET_BAD)
		continue;

		if(read_fds) {
		if(!FD_ISSET(server->tcp_socket, read_fds))
		continue;
		}
		else {
		if(server->tcp_socket != read_fd)
		continue;
		}

		if (server->tcp_lenbuf_pos != 2)
		{
		/* We haven't yet read a length word, so read that (or
		@@ -294,22 +342,34 @@ static void read_tcp_data(ares_channel channel, fd_set *read_fds, time_t now)

		/* If any UDP sockets select true for reading, process them. */
		static void read_udp_packets(ares_channel channel, fd_set *read_fds,
		time_t now)
		ares_socket_t read_fd, time_t now)
		{
		struct server_state *server;
		int i;
		ssize_t count;
		unsigned char buf[PACKETSZ + 1];

		if(!read_fds && (read_fd == ARES_SOCKET_BAD))
		/* no possible action */
		return;

		for (i = 0; i < channel->nservers; i++)
		{
		/* Make sure the server has a socket and is selected in read_fds. */
		server = &channel->servers[i];

		if (server->udp_socket == ARES_SOCKET_BAD \|\|
		!FD_ISSET(server->udp_socket, read_fds))
		if (server->udp_socket == ARES_SOCKET_BAD)
		continue;

		if(read_fds) {
		if(!FD_ISSET(server->udp_socket, read_fds))
		continue;
		}
		else {
		if(server->udp_socket != read_fd)
		continue;
		}

		count = sread(server->udp_socket, buf, sizeof(buf));
		if (count == -1 && try_again(SOCKERRNO))
		continue;

ares/setup.h

+1 −13

Original line number	Diff line number	Diff line
		@@ -3,7 +3,7 @@

		/* $Id$ */

		/* Copyright (C) 2004 - 2005 by Daniel Stenberg et al
		/* Copyright (C) 2004 - 2007 by Daniel Stenberg et al
		*
		* Permission to use, copy, modify, and distribute this software and its
		* documentation for any purpose and without fee is hereby granted, provided
		@@ -117,18 +117,6 @@
		#undef VERSION
		#undef PACKAGE

		/*
		* Typedef our socket type
		*/

		#ifdef USE_WINSOCK
		typedef SOCKET ares_socket_t;
		#define ARES_SOCKET_BAD INVALID_SOCKET
		#else
		typedef int ares_socket_t;
		#define ARES_SOCKET_BAD -1
		#endif

		/*
		* Assume a few thing unless they're set by configure
		*/