Hello,
Here comes another feature patch for the reSIProcate transition from
ares to c-ares. The embedded copy supports querying IPv6 nameservers and
setting these up via the options structure.
The reSIProcate developers substituted the in_addr field by an union
contruct to hold the in6_addr. As this would break API compatibility, I
have added a second nservers and servers field and suffixed it with a '6'.
For the internal part I've declared the mf_address structure:
struct mf_address {
sa_family_t family;
union
{
struct in_addr in4;
struct in6_addr in6;
} mf_addr;
};
Another approach would be the usage of sockaddr_storage. But all the
casting to sockaddr_in and sockaddr_in6 made the code very ugly and hard
to read. Maybe some macros would help here. The other drawback of
sockaddr_storage is it's relativly young age, so that it's (probably)
not available on all target platforms.
Things that needs to be done:
* Guard the AF_INET6 specific part by the preprocessor. What
(config-)defines would be optimal for this task? A combination of
HAVE_AF_INET6, HAVE_STRUCT_SOCKADDR_STORAGE, HAVE_STRUCT_SOCKADDR_IN6?
* Test on all supported target platforms
* Documentation
But before I continue I'd like to get some feedback on this issue.
Thanks,
Gregor
Index: adig.c
===================================================================
RCS file: /cvsroot/curl/curl/ares/adig.c,v
retrieving revision 1.36
diff -u -3 -p -r1.36 adig.c
--- adig.c 17 Oct 2008 19:04:53 -0000 1.36
+++ adig.c 23 Nov 2008 17:29:36 -0000
@@ -152,7 +152,6 @@ static const char *opcodes[] = {
"UPDATEA", "UPDATED", "UPDATEDA", "UPDATEM", "UPDATEMA",
"ZONEINIT", "ZONEREF"
};
- struct in_addr inaddr;
static const char *rcodes[] = {
"NOERROR", "FORMERR", "SERVFAIL", "NXDOMAIN", "NOTIMP", "REFUSED",
@@ -180,6 +179,8 @@ int main(int argc, char **argv)
struct hostent *hostent;
fd_set read_fds, write_fds;
struct timeval *tvp, tv;
+ struct in_addr inaddr;
+ struct in6_addr in6addr;
#ifdef USE_WINSOCK
WORD wVersionRequested = MAKEWORD(USE_WINSOCK,USE_WINSOCK);
@@ -190,7 +191,9 @@ int main(int argc, char **argv)
options.flags = ARES_FLAG_NOCHECKRESP;
options.servers = NULL;
options.nservers = 0;
- while ((c = ares_getopt(argc, argv, "df:s:c:t:T:U:")) != -1)
+ options.servers6 = NULL;
+ options.nservers6 = 0;
+ while ((c = ares_getopt(argc, argv, "df:s:S:c:t:T:U:")) != -1)
{
switch (c)
{
@@ -237,6 +240,26 @@ int main(int argc, char **argv)
optmask |= ARES_OPT_SERVERS;
break;
+ case 'S':
+ /* Add a server, and specify servers in the option mask. */
+ if (ares_inet_pton(AF_INET6, optarg, &in6addr) <= 0)
+ {
+ fprintf(stderr, "adig: inet_pton returned an error on server %s.\n", optarg);
+ return 1;
+ }
+ options.servers6 = realloc(options.servers6, (options.nservers6 + 1)
+ * sizeof(struct in6_addr));
+ if (!options.servers6)
+ {
+ fprintf(stderr, "Out of memory!\n");
+ return 1;
+ }
+ memcpy(&options.servers6[options.nservers6], &in6addr,
+ sizeof(struct in_addr));
+ options.nservers6++;
+ optmask |= ARES_OPT_SERVERS6;
+ break;
+
case 'c':
/* Set the query class. */
for (i = 0; i < nclasses; i++)
@@ -715,7 +738,7 @@ static const char *class_name(int dnscla
static void usage(void)
{
- fprintf(stderr, "usage: adig [-f flag] [-s server] [-c class] "
+ fprintf(stderr, "usage: adig [-f flag] [-s IPv4 server] [-S IPv6 server] [-c class] "
"[-t type] [-p port] name ...\n");
exit(1);
}
Index: ares.h
===================================================================
RCS file: /cvsroot/curl/curl/ares/ares.h,v
retrieving revision 1.42
diff -u -3 -p -r1.42 ares.h
--- ares.h 19 Nov 2008 15:16:16 -0000 1.42
+++ ares.h 23 Nov 2008 17:29:36 -0000
@@ -115,6 +115,7 @@ extern "C" {
#define ARES_OPT_SOCK_RCVBUF (1 << 12)
#define ARES_OPT_TIMEOUTMS (1 << 13)
#define ARES_OPT_ROTATE (1 << 14)
+#define ARES_OPT_SERVERS6 (1 << 15)
/* Nameinfo flag values */
#define ARES_NI_NOFQDN (1 << 0)
@@ -180,6 +181,15 @@ typedef void (*ares_sock_state_cb)(void
struct apattern;
+#if !defined(HAVE_STRUCT_IN6_ADDR) && !defined(s6_addr)
+struct in6_addr {
+ union {
+ unsigned char _S6_u8[16];
+ } _S6_un;
+};
+#define s6_addr _S6_un._S6_u8
+#endif
+
struct ares_options {
int flags;
int timeout; /* in seconds or milliseconds, depending on options */
@@ -199,6 +209,8 @@ struct ares_options {
void *sock_state_cb_data;
struct apattern *sortlist;
int nsort;
+ struct in6_addr *servers6;
+ int nservers6;
};
struct hostent;
@@ -251,14 +263,6 @@ int ares_expand_name(const unsigned char
int ares_expand_string(const unsigned char *encoded, const unsigned char *abuf,
int alen, unsigned char **s, long *enclen);
-#if !defined(HAVE_STRUCT_IN6_ADDR) && !defined(s6_addr)
-struct in6_addr {
- union {
- unsigned char _S6_u8[16];
- } _S6_un;
-};
-#define s6_addr _S6_un._S6_u8
-#endif
struct addrttl {
struct in_addr ipaddr;
Index: ares_init.c
===================================================================
RCS file: /cvsroot/curl/curl/ares/ares_init.c,v
retrieving revision 1.81
diff -u -3 -p -r1.81 ares_init.c
--- ares_init.c 20 Nov 2008 07:50:48 -0000 1.81
+++ ares_init.c 23 Nov 2008 17:29:36 -0000
@@ -261,7 +261,7 @@ int ares_init_options(ares_channel *chan
int ares_save_options(ares_channel channel, struct ares_options *options,
int *optmask)
{
- int i;
+ int i, s;
/* Zero everything out */
memset(options, 0, sizeof(struct ares_options));
@@ -272,7 +272,7 @@ int ares_save_options(ares_channel chann
(*optmask) = (ARES_OPT_FLAGS|ARES_OPT_TRIES|ARES_OPT_NDOTS|
ARES_OPT_UDP_PORT|ARES_OPT_TCP_PORT|ARES_OPT_SOCK_STATE_CB|
ARES_OPT_SERVERS|ARES_OPT_DOMAINS|ARES_OPT_LOOKUPS|
- ARES_OPT_SORTLIST|ARES_OPT_TIMEOUTMS);
+ ARES_OPT_SORTLIST|ARES_OPT_TIMEOUTMS|ARES_OPT_SERVERS6);
/* Copy easy stuff */
options->flags = channel->flags;
@@ -287,16 +287,38 @@ int ares_save_options(ares_channel chann
options->sock_state_cb = channel->sock_state_cb;
options->sock_state_cb_data = channel->sock_state_cb_data;
- /* Copy servers */
- if (channel->nservers) {
+ /* Count servers */
+ options->nservers = options->nservers6 = 0;
+ for (i = 0; i < channel->nservers; i++)
+ switch (channel->servers[i].address.family)
+ {
+ case AF_INET: options->nservers++; break;
+ case AF_INET6: options->nservers6++; break;
+ }
+
+ /* Copy IPv4 servers */
+ if (options->nservers) {
options->servers =
- malloc(channel->nservers * sizeof(struct server_state));
- if (!options->servers && channel->nservers != 0)
+ malloc(options->nservers * sizeof(struct in_addr));
+ if (!options->servers)
+ return ARES_ENOMEM;
+ for (i = s = 0; i < channel->nservers; i++)
+ if (channel->servers[i].address.family != AF_INET)
+ continue;
+ options->servers[s++] = channel->servers[i].address.mf_addr.in4;
+ }
+
+ /* Copy IPv6 servers */
+ if (options->nservers6) {
+ options->servers6 =
+ malloc(options->nservers6 * sizeof(struct in6_addr));
+ if (!options->servers6)
return ARES_ENOMEM;
- for (i = 0; i < channel->nservers; i++)
- options->servers[i] = channel->servers[i].addr;
+ for (i = s = 0; i < channel->nservers; i++)
+ if (channel->servers[i].address.family != AF_INET6)
+ continue;
+ options->servers6[s++] = channel->servers[i].address.mf_addr.in6;
}
- options->nservers = channel->nservers;
/* copy domains */
if (channel->ndomains) {
@@ -373,19 +395,41 @@ static int init_by_options(ares_channel
channel->socket_receive_buffer_size = options->socket_receive_buffer_size;
/* Copy the servers, if given. */
- if ((optmask & ARES_OPT_SERVERS) && channel->nservers == -1)
+ if ((optmask & (ARES_OPT_SERVERS|ARES_OPT_SERVERS6)) && channel->nservers == -1)
{
+ int n = 0;
+ if ((optmask & ARES_OPT_SERVERS) && options->nservers > 0)
+ n += options->nservers;
+ if ((optmask & ARES_OPT_SERVERS6) && options->nservers6 > 0)
+ n += options->nservers6;
+
/* Avoid zero size allocations at any cost */
- if (options->nservers > 0)
+ if (n > 0)
{
channel->servers =
- malloc(options->nservers * sizeof(struct server_state));
+ calloc(n, sizeof(struct server_state));
if (!channel->servers)
return ARES_ENOMEM;
- for (i = 0; i < options->nservers; i++)
- channel->servers[i].addr = options->servers[i];
+
+ n = 0;
+
+ /* copy IPv4 */
+ if ((optmask & ARES_OPT_SERVERS) && options->nservers > 0)
+ for (i = 0; i < options->nservers; i++, n++)
+ {
+ channel->servers[n].address.family = AF_INET;
+ channel->servers[n].address.mf_addr.in4 = options->servers[i];
+ }
+
+ /* copy IPv6 */
+ if ((optmask & ARES_OPT_SERVERS6) && options->nservers6 > 0)
+ for (i = 0; i < options->nservers6; i++, n++)
+ {
+ channel->servers[n].address.family = AF_INET6;
+ channel->servers[n].address.mf_addr.in6 = options->servers6[i];
+ }
}
- channel->nservers = options->nservers;
+ channel->nservers = n;
}
/* Copy the domains, if given. Keep channel->ndomains consistent so
@@ -950,7 +994,8 @@ static int init_by_defaults(ares_channel
rc = ARES_ENOMEM;
goto error;
}
- channel->servers[0].addr.s_addr = htonl(INADDR_LOOPBACK);
+ channel->servers[0].address.family = AF_INET;
+ channel->servers[0].address.mf_addr.in4.s_addr = htonl(INADDR_LOOPBACK);
channel->nservers = 1;
}
@@ -1139,7 +1184,8 @@ static int config_nameserver(struct serv
newserv = realloc(*servers, (*nservers + 1) * sizeof(struct server_state));
if (!newserv)
return ARES_ENOMEM;
- newserv[*nservers].addr = addr;
+ newserv[*nservers].address.family = AF_INET;
+ newserv[*nservers].address.mf_addr.in4 = addr;
*servers = newserv;
(*nservers)++;
#endif
Index: ares_private.h
===================================================================
RCS file: /cvsroot/curl/curl/ares/ares_private.h,v
retrieving revision 1.39
diff -u -3 -p -r1.39 ares_private.h
--- ares_private.h 20 Nov 2008 07:50:48 -0000 1.39
+++ ares_private.h 23 Nov 2008 17:29:36 -0000
@@ -131,8 +131,17 @@ struct send_request {
struct send_request *next;
};
+struct mf_address {
+ sa_family_t family;
+ union
+ {
+ struct in_addr in4;
+ struct in6_addr in6;
+ } mf_addr;
+};
+
struct server_state {
- struct in_addr addr;
+ struct mf_address address;
ares_socket_t udp_socket;
ares_socket_t tcp_socket;
Index: ares_process.c
===================================================================
RCS file: /cvsroot/curl/curl/ares/ares_process.c,v
retrieving revision 1.71
diff -u -3 -p -r1.71 ares_process.c
--- ares_process.c 13 Nov 2008 18:56:56 -0000 1.71
+++ ares_process.c 23 Nov 2008 17:29:37 -0000
@@ -97,6 +97,7 @@ static int open_tcp_socket(ares_channel
static int open_udp_socket(ares_channel channel, struct server_state *server);
static int same_questions(const unsigned char *qbuf, int qlen,
const unsigned char *abuf, int alen);
+static int same_address(const struct sockaddr_storage *from, const struct mf_address *address);
static void end_query(ares_channel channel, struct query *query, int status,
unsigned char *abuf, int alen);
@@ -428,7 +429,7 @@ static void read_udp_packets(ares_channe
ssize_t count;
unsigned char buf[PACKETSZ + 1];
#ifdef HAVE_RECVFROM
- struct sockaddr_in from;
+ struct sockaddr_storage from;
socklen_t fromlen;
#endif
@@ -466,6 +467,7 @@ static void read_udp_packets(ares_channe
do {
#ifdef HAVE_RECVFROM
fromlen = sizeof(from);
+ fprintf(stderr, "Size: %u\n", fromlen);
count = (ssize_t)recvfrom(server->udp_socket, (void *)buf, sizeof(buf),
0, (struct sockaddr *)&from, &fromlen);
#else
@@ -476,7 +478,7 @@ static void read_udp_packets(ares_channe
else if (count <= 0)
handle_error(channel, i, now);
#ifdef HAVE_RECVFROM
- else if (from.sin_addr.s_addr != server->addr.s_addr)
+ else if (!same_address(&from, &server->address))
/* Address response came from did not match the address
* we sent the request to. Someone may be attempting
* to perform a cache poisoning attack */
@@ -883,10 +885,33 @@ static int open_tcp_socket(ares_channel
{
ares_socket_t s;
int opt;
- struct sockaddr_in sockin;
+ struct sockaddr_in sin;
+ struct sockaddr_in6 sin6;
+ const struct sockaddr *sa;
+ socklen_t sock_len;
+
+ switch (server->address.family)
+ {
+ case AF_INET:
+ memset(&sin, 0, sizeof(sin));
+ sin.sin_addr = server->address.mf_addr.in4;
+ sin.sin_port = (unsigned short)(channel->tcp_port & 0xffff);
+ sock_len = sizeof(sin);
+ sa = (const struct sockaddr *)&sin;
+ break;
+ case AF_INET6:
+ memset(&sin6, 0, sizeof(sin6));
+ sin6.sin6_addr = server->address.mf_addr.in6;
+ sin6.sin6_port = (unsigned short)(channel->tcp_port & 0xffff);
+ sock_len = sizeof(sin6);
+ sa = (const struct sockaddr *)&sin6;
+ break;
+ default:
+ return -1;
+ }
/* Acquire a socket. */
- s = socket(AF_INET, SOCK_STREAM, 0);
+ s = socket(server->address.family, SOCK_STREAM, 0);
if (s == ARES_SOCKET_BAD)
return -1;
@@ -912,11 +937,7 @@ static int open_tcp_socket(ares_channel
}
/* Connect to the server. */
- memset(&sockin, 0, sizeof(sockin));
- sockin.sin_family = AF_INET;
- sockin.sin_addr = server->addr;
- sockin.sin_port = (unsigned short)(channel->tcp_port & 0xffff);
- if (connect(s, (struct sockaddr *) &sockin, sizeof(sockin)) == -1)
+ if (connect(s, sa, sock_len) == -1)
{
int err = SOCKERRNO;
@@ -937,10 +958,35 @@ static int open_tcp_socket(ares_channel
static int open_udp_socket(ares_channel channel, struct server_state *server)
{
ares_socket_t s;
- struct sockaddr_in sockin;
+ struct sockaddr_in sin;
+ struct sockaddr_in6 sin6;
+ const struct sockaddr *sa;
+ socklen_t sock_len;
+
+ switch (server->address.family)
+ {
+ case AF_INET:
+ memset(&sin, 0, sizeof(sin));
+ sin.sin_family = AF_INET;
+ sin.sin_addr = server->address.mf_addr.in4;
+ sin.sin_port = (unsigned short)(channel->tcp_port & 0xffff);
+ sock_len = sizeof(sin);
+ sa = (const struct sockaddr *)&sin;
+ break;
+ case AF_INET6:
+ memset(&sin6, 0, sizeof(sin6));
+ sin6.sin6_family = AF_INET6;
+ sin6.sin6_addr = server->address.mf_addr.in6;
+ sin6.sin6_port = (unsigned short)(channel->tcp_port & 0xffff);
+ sock_len = sizeof(sin6);
+ sa = (const struct sockaddr *)&sin6;
+ break;
+ default:
+ return -1;
+ }
/* Acquire a socket. */
- s = socket(AF_INET, SOCK_DGRAM, 0);
+ s = socket(server->address.family, SOCK_DGRAM, 0);
if (s == ARES_SOCKET_BAD)
return -1;
@@ -952,11 +998,7 @@ static int open_udp_socket(ares_channel
}
/* Connect to the server. */
- memset(&sockin, 0, sizeof(sockin));
- sockin.sin_family = AF_INET;
- sockin.sin_addr = server->addr;
- sockin.sin_port = (unsigned short)(channel->udp_port & 0xffff);
- if (connect(s, (struct sockaddr *) &sockin, sizeof(sockin)) == -1)
+ if (connect(s, sa, sock_len) == -1)
{
int err = SOCKERRNO;
@@ -1052,6 +1094,22 @@ static int same_questions(const unsigned
return 1;
}
+static int same_address(const struct sockaddr_storage *from, const struct mf_address *address)
+{
+ if (from->ss_family == AF_INET && address->family == AF_INET)
+ {
+ const struct sockaddr_in *from_in = (const struct sockaddr_in*)from;
+ return from_in->sin_addr.s_addr == address->mf_addr.in4.s_addr;
+ }
+ else if (from->ss_family == AF_INET6 && address->family == AF_INET6)
+ {
+ const struct sockaddr_in6 *from_in6 = (const struct sockaddr_in6*)from;
+ return from_in6->sin6_addr.s6_addr == address->mf_addr.in6.s6_addr;
+ }
+
+ return 0;
+}
+
static void end_query (ares_channel channel, struct query *query, int status,
unsigned char *abuf, int alen)
{
