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local-bind: Support binding to local interface/IPs
Add 3 new functions to set the local binding for the out-going socket connection, and add ares_set_servers_csv() to set a list of servers at once as a comma-separated string. Signed-off-by: Ben Greear <greearb@candelatech.com>
This commit is contained in:
Ben Greear
committed by
Daniel Stenberg
Daniel Stenberg
parent
45a09b7efb
commit
e3b04e5a47
19
ares.h
19
ares.h
@ -313,6 +313,20 @@ CARES_EXTERN void ares_destroy(ares_channel channel);
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CARES_EXTERN void ares_cancel(ares_channel channel);
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/* These next 3 configure local binding for the out-going socket
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* connection. Use these to specify source IP and/or network device
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* on multi-homed systems.
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*/
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CARES_EXTERN void ares_set_local_ip4(ares_channel channel, uint32_t local_ip);
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/* local_ip6 should be 16 bytes in length */
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CARES_EXTERN void ares_set_local_ip6(ares_channel channel,
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const unsigned char* local_ip6);
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/* local_dev_name should be null terminated. */
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CARES_EXTERN void ares_set_local_dev(ares_channel channel,
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const char* local_dev_name);
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CARES_EXTERN void ares_set_socket_callback(ares_channel channel,
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ares_sock_create_callback callback,
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void *user_data);
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@ -496,6 +510,7 @@ CARES_EXTERN void ares_free_data(void *dataptr);
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CARES_EXTERN const char *ares_strerror(int code);
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/* TODO: Hold port here as well. */
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struct ares_addr_node {
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struct ares_addr_node *next;
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int family;
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@ -508,6 +523,10 @@ struct ares_addr_node {
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CARES_EXTERN int ares_set_servers(ares_channel channel,
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struct ares_addr_node *servers);
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/* Incomming string format: host[:port][,host[:port]]... */
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CARES_EXTERN int ares_set_servers_csv(ares_channel channel,
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const char* servers);
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CARES_EXTERN int ares_get_servers(ares_channel channel,
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struct ares_addr_node **servers);
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30
ares_init.c
30
ares_init.c
@ -172,6 +172,10 @@ int ares_init_options(ares_channel *channelptr, struct ares_options *options,
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channel->last_server = 0;
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channel->last_timeout_processed = (time_t)now.tv_sec;
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memset(&channel->local_dev_name, 0, sizeof(channel->local_dev_name));
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channel->local_ip4 = 0;
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memset(&channel->local_ip6, 0, sizeof(channel->local_ip6));
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/* Initialize our lists of queries */
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ares__init_list_head(&(channel->all_queries));
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for (i = 0; i < ARES_QID_TABLE_SIZE; i++)
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@ -286,6 +290,10 @@ int ares_dup(ares_channel *dest, ares_channel src)
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(*dest)->sock_create_cb = src->sock_create_cb;
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(*dest)->sock_create_cb_data = src->sock_create_cb_data;
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strncpy((*dest)->local_dev_name, src->local_dev_name, sizeof(src->local_dev_name));
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(*dest)->local_ip4 = src->local_ip4;
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memcpy((*dest)->local_ip6, src->local_ip6, sizeof(src->local_ip6));
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/* Full name server cloning required when not all are IPv4 */
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for (i = 0; i < src->nservers; i++)
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{
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@ -1604,6 +1612,28 @@ unsigned short ares__generate_new_id(rc4_key* key)
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return r;
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}
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void ares_set_local_ip4(ares_channel channel, uint32_t local_ip)
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{
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channel->local_ip4 = local_ip;
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}
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/* local_ip6 should be 16 bytes in length */
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void ares_set_local_ip6(ares_channel channel,
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const unsigned char* local_ip6)
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{
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memcpy(&channel->local_ip6, local_ip6, sizeof(channel->local_ip6));
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}
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/* local_dev_name should be null terminated. */
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void ares_set_local_dev(ares_channel channel,
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const char* local_dev_name)
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{
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strncpy(channel->local_dev_name, local_dev_name,
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sizeof(channel->local_dev_name));
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channel->local_dev_name[sizeof(channel->local_dev_name) - 1] = 0;
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}
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void ares_set_socket_callback(ares_channel channel,
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ares_sock_create_callback cb,
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void *data)
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125
ares_options.c
125
ares_options.c
@ -21,6 +21,7 @@
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#include "ares.h"
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#include "ares_data.h"
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#include "ares_private.h"
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#include "inet_net_pton.h"
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int ares_get_servers(ares_channel channel,
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@ -125,3 +126,127 @@ int ares_set_servers(ares_channel channel,
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return ARES_SUCCESS;
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}
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/* Incomming string format: host[:port][,host[:port]]... */
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int ares_set_servers_csv(ares_channel channel,
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const char* _csv)
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{
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struct ares_addr_node *srvr;
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int num_srvrs = 0;
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int i;
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char* csv = NULL;
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char* ptr;
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char* start_host;
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int port;
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bool found_port;
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int rv = ARES_SUCCESS;
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struct ares_addr_node *servers = NULL;
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struct ares_addr_node *last = NULL;
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if (ares_library_initialized() != ARES_SUCCESS)
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return ARES_ENOTINITIALIZED;
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if (!channel)
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return ARES_ENODATA;
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ares__destroy_servers_state(channel);
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i = strlen(_csv);
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if (i == 0)
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return ARES_SUCCESS; /* blank all servers */
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csv = malloc(i + 2);
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strcpy(csv, _csv);
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if (csv[i-1] != ',') { /* make parsing easier by ensuring ending ',' */
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csv[i] = ',';
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csv[i+1] = 0;
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}
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ptr = csv;
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start_host = csv;
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found_port = false;
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for (ptr; *ptr; ptr++) {
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if (*ptr == ',') {
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char* pp = ptr - 1;
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struct in_addr in4;
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struct ares_in6_addr in6;
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struct ares_addr_node *s = NULL;
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*ptr = 0; /* null terminate host:port string */
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/* Got an entry..see if port was specified. */
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while (pp > start_host) {
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if (*pp == ':')
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break; /* yes */
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if (!isdigit(*pp)) {
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/* Found end of digits before we found :, so wasn't a port */
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pp = ptr;
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break;
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}
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pp--;
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}
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if ((pp != start_host) && ((pp + 1) < ptr)) {
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/* Found it. */
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found_port = true;
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port = atoi(pp + 1);
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*pp = 0; /* null terminate host */
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}
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/* resolve host, try ipv4 first, rslt is in network byte order */
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rv = ares_inet_pton(AF_INET, start_host, &in4);
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if (!rv) {
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/* Ok, try IPv6 then */
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rv = ares_inet_pton(AF_INET6, start_host, &in6);
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if (!rv) {
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rv = ARES_EBADSTR;
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goto out;
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}
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/* was ipv6, add new server */
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s = malloc(sizeof(*s));
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if (!s) {
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rv = ARES_ENOMEM;
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goto out;
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}
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s->family = AF_INET6;
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memcpy(&s->addr, &in6, sizeof(struct ares_in6_addr));
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}
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else {
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/* was ipv4, add new server */
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s = malloc(sizeof(*s));
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if (!s) {
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rv = ARES_ENOMEM;
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goto out;
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}
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s->family = AF_INET;
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memcpy(&s->addr, &in4, sizeof(struct in_addr));
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}
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if (s) {
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/* TODO: Add port to ares_addr_node and assign it here. */
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s->next = NULL;
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if (last) {
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last->next = s;
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}
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else {
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servers = s;
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last = s;
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}
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}
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/* Set up for next one */
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found_port = false;
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start_host = ptr + 1;
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}
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}
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rv = ares_set_servers(channel, servers);
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out:
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if (csv)
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free(csv);
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while (servers) {
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struct ares_addr_node *s = servers;
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servers = servers->next;
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free(s);
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}
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return rv;
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}
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@ -257,6 +257,13 @@ struct ares_channeldata {
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int nsort;
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char *lookups;
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/* For binding to local devices and/or IP addresses. Leave
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* them null/zero for no binding.
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*/
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char local_dev_name[32];
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uint32_t local_ip4;
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unsigned char local_ip6[16];
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int optmask; /* the option bitfield passed in at init time */
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/* Server addresses and communications state */
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@ -91,7 +91,6 @@ static void skip_server(ares_channel channel, struct query *query,
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int whichserver);
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static void next_server(ares_channel channel, struct query *query,
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struct timeval *now);
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static int configure_socket(ares_socket_t s, ares_channel channel);
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static int open_tcp_socket(ares_channel channel, struct server_state *server);
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static int open_udp_socket(ares_channel channel, struct server_state *server);
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static int same_questions(const unsigned char *qbuf, int qlen,
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@ -869,7 +868,7 @@ static int setsocknonblock(ares_socket_t sockfd, /* operate on this */
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#endif
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}
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static int configure_socket(ares_socket_t s, ares_channel channel)
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static int configure_socket(ares_socket_t s, int family, ares_channel channel)
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{
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setsocknonblock(s, TRUE);
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@ -892,8 +891,39 @@ static int configure_socket(ares_socket_t s, ares_channel channel)
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sizeof(channel->socket_receive_buffer_size)) == -1)
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return -1;
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#ifdef SO_BINDTODEVICE
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if (channel->local_dev_name[0]) {
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if (setsockopt(s, SOL_SOCKET, SO_BINDTODEVICE,
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channel->local_dev_name, sizeof(channel->local_dev_name))) {
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/* Only root can do this, and usually not fatal if it doesn't work, so */
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/* just continue on. */
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}
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}
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#endif
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if (family == AF_INET) {
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if (channel->local_ip4) {
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struct sockaddr_in sa;
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memset(&sa, 0, sizeof(sa));
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sa.sin_family = AF_INET;
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sa.sin_addr.s_addr = htonl(channel->local_ip4);
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if (bind(s, (struct sockaddr*)&sa, sizeof(sa)) < 0)
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return -1;
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}
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}
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else if (family == AF_INET6) {
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if (memcmp(channel->local_ip6, &in6addr_any, sizeof(channel->local_ip6)) != 0) {
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struct sockaddr_in6 sa;
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memset(&sa, 0, sizeof(sa));
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sa.sin6_family = AF_INET6;
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memcpy(&sa.sin6_addr, channel->local_ip6, sizeof(channel->local_ip6));
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if (bind(s, (struct sockaddr*)&sa, sizeof(sa)) < 0)
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return -1;
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}
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}
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return 0;
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}
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}
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static int open_tcp_socket(ares_channel channel, struct server_state *server)
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{
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@ -936,7 +966,7 @@ static int open_tcp_socket(ares_channel channel, struct server_state *server)
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return -1;
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/* Configure it. */
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if (configure_socket(s, channel) < 0)
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if (configure_socket(s, server->addr.family, channel) < 0)
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{
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sclose(s);
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return -1;
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@ -1028,7 +1058,7 @@ static int open_udp_socket(ares_channel channel, struct server_state *server)
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return -1;
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/* Set the socket non-blocking. */
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if (configure_socket(s, channel) < 0)
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if (configure_socket(s, server->addr.family, channel) < 0)
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{
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sclose(s);
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return -1;
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39
ares_set_local_dev.3
Normal file
39
ares_set_local_dev.3
Normal file
@ -0,0 +1,39 @@
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.\"
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.\" Copyright 2010 by Ben Greear <greearb@candelatech.com>
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.\"
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.\" Permission to use, copy, modify, and distribute this
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.\" software and its documentation for any purpose and without
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.\" fee is hereby granted, provided that the above copyright
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.\" notice appear in all copies and that both that copyright
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.\" notice and this permission notice appear in supporting
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.\" documentation, and that the name of M.I.T. not be used in
|
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.\" advertising or publicity pertaining to distribution of the
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.\" software without specific, written prior permission.
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.\" M.I.T. makes no representations about the suitability of
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.\" this software for any purpose. It is provided "as is"
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.\" without express or implied warranty.
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.\"
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.TH ARES_SET_LOCAL_DEV 3 "30 June 2010"
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.SH NAME
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ares_set_local_dev \- Bind to a specific network device when creating sockets.
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.SH SYNOPSIS
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.nf
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.B #include <ares.h>
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.PP
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.B void ares_set_local_dev(ares_channel \fIchannel\fP, const char* \fIlocal_dev_name\fP)
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.fi
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.SH DESCRIPTION
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The \fBares_set_local_dev\fP function causes all future sockets
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to be bound to this device with SO_BINDTODEVICE. This forces communications
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to go over a certain interface, which can be useful on multi-homed machines.
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This option is only supported on Linux, and root priviledges are required
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for the option to work. If SO_BINDTODEVICE is not supported or the
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setsocktop call fails (probably because of permissions), the error is
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silently ignored.
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.SH SEE ALSO
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.BR ares_set_local_ipv4 (3)
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.BR ares_set_local_ipv6 (3)
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.SH NOTES
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This function was added in c-ares 1.7.2
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.SH AUTHOR
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Ben Greear
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34
ares_set_local_ip4.3
Normal file
34
ares_set_local_ip4.3
Normal file
@ -0,0 +1,34 @@
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.\"
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.\" Copyright 2010 by Ben Greear <greearb@candelatech.com>
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.\"
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.\" Permission to use, copy, modify, and distribute this
|
||||
.\" software and its documentation for any purpose and without
|
||||
.\" fee is hereby granted, provided that the above copyright
|
||||
.\" notice appear in all copies and that both that copyright
|
||||
.\" notice and this permission notice appear in supporting
|
||||
.\" documentation, and that the name of M.I.T. not be used in
|
||||
.\" advertising or publicity pertaining to distribution of the
|
||||
.\" software without specific, written prior permission.
|
||||
.\" M.I.T. makes no representations about the suitability of
|
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.\" this software for any purpose. It is provided "as is"
|
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.\" without express or implied warranty.
|
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.\"
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.TH ARES_SET_LOCAL_IP4 3 "30 June 2010"
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.SH NAME
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ares_set_local_ip4 \- Set local IPv4 address outgoing requests.
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.SH SYNOPSIS
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.nf
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.B #include <ares.h>
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.PP
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.B void ares_set_local_ip4(ares_channel \fIchannel\fP, uint32_t \fIlocal_ip\fP)
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.fi
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.SH DESCRIPTION
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The \fBares_set_local_ip4\fP function sets the IP address for outbound
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requests. This allows users to specify outbound interfaces when used
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on multi-homed systems.
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.SH SEE ALSO
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.BR ares_set_local_ip6 (3)
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.SH NOTES
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This function was added in c-ares 1.7.2
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.SH AUTHOR
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Ben Greear
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34
ares_set_local_ip6.3
Normal file
34
ares_set_local_ip6.3
Normal file
@ -0,0 +1,34 @@
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.\"
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.\" Copyright 2010 by Ben Greear <greearb@candelatech.com>
|
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.\"
|
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.\" Permission to use, copy, modify, and distribute this
|
||||
.\" software and its documentation for any purpose and without
|
||||
.\" fee is hereby granted, provided that the above copyright
|
||||
.\" notice appear in all copies and that both that copyright
|
||||
.\" notice and this permission notice appear in supporting
|
||||
.\" documentation, and that the name of M.I.T. not be used in
|
||||
.\" advertising or publicity pertaining to distribution of the
|
||||
.\" software without specific, written prior permission.
|
||||
.\" M.I.T. makes no representations about the suitability of
|
||||
.\" this software for any purpose. It is provided "as is"
|
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.\" without express or implied warranty.
|
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.\"
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.TH ARES_SET_LOCAL_IP6 3 "30 June 2010"
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.SH NAME
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ares_set_local_ip6 \- Set local IPv6 address outgoing requests.
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.SH SYNOPSIS
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.nf
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.B #include <ares.h>
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.PP
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.B void ares_set_local_ip6(ares_channel \fIchannel\fP, const unsigned char* \fIlocal_ip6\fP)
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.fi
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.SH DESCRIPTION
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The \fBares_set_local_ip6\fP function sets the IPv6 address for outbound
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IPv6 requests. This allows users to specify outbound interfaces when used
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on multi-homed systems. The local_ip6 argument must be 16 bytes in length.
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.SH SEE ALSO
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.BR ares_set_local_ip4 (3)
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.SH NOTES
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This function was added in c-ares 1.7.2
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.SH AUTHOR
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Ben Greear
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@ -1,6 +1,5 @@
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.\"
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.\" Copyright 1998 by the Massachusetts Institute of Technology.
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.\" Copyright (C) 2008-2010 by Daniel Stenberg
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.\" Copyright 2010 by Ben Greear <greearb@candelatech.com>
|
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.\"
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.\" Permission to use, copy, modify, and distribute this
|
||||
.\" software and its documentation for any purpose and without
|
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@ -67,6 +66,7 @@ was invalid.
|
||||
.B ARES_ENOTINITIALIZED
|
||||
c-ares library initialization not yet performed.
|
||||
.SH SEE ALSO
|
||||
.BR ares_set_servers_csv (3),
|
||||
.BR ares_get_servers (3),
|
||||
.BR ares_init_options (3),
|
||||
.BR ares_dup(3)
|
||||
|
||||
43
ares_set_servers_csv.3
Normal file
43
ares_set_servers_csv.3
Normal file
@ -0,0 +1,43 @@
|
||||
.\"
|
||||
.\" Copyright 2010 by Ben Greear <greearb@candelatech.com>
|
||||
.\"
|
||||
.\" Permission to use, copy, modify, and distribute this
|
||||
.\" software and its documentation for any purpose and without
|
||||
.\" fee is hereby granted, provided that the above copyright
|
||||
.\" notice appear in all copies and that both that copyright
|
||||
.\" notice and this permission notice appear in supporting
|
||||
.\" documentation, and that the name of M.I.T. not be used in
|
||||
.\" advertising or publicity pertaining to distribution of the
|
||||
.\" software without specific, written prior permission.
|
||||
.\" M.I.T. makes no representations about the suitability of
|
||||
.\" this software for any purpose. It is provided "as is"
|
||||
.\" without express or implied warranty.
|
||||
.\"
|
||||
.TH ARES_SET_SERVERS_CSV 3 "30 June 2010"
|
||||
.SH NAME
|
||||
ares_set_servers_csv \- Set list of DNS servers to be used.
|
||||
.SH SYNOPSIS
|
||||
.nf
|
||||
.B #include <ares.h>
|
||||
.PP
|
||||
.B void ares_set_servers_csv(ares_channel \fIchannel\fP, const char* \fIservers\fP)
|
||||
.fi
|
||||
.SH DESCRIPTION
|
||||
The \fBares_set_servers_csv\fP function sets the list of DNS servers
|
||||
that ARES will query. The format of the servers option is:
|
||||
|
||||
host[:port][,host[:port]]...
|
||||
|
||||
For example:
|
||||
|
||||
192.168.1.100,192.168.1.101,3.4.5.6
|
||||
|
||||
.SH SEE ALSO
|
||||
.BR ares_set_servers (3)
|
||||
.SH NOTES
|
||||
The port option is currently ignored by c-ares internals
|
||||
and the standard port is always used.
|
||||
|
||||
This function was added in c-ares 1.7.2
|
||||
.SH AUTHOR
|
||||
Ben Greear
|
||||
Reference in New Issue
Block a user