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ares_init.c: get_iphlpapi_dns_info() refactoring

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pull/8/merge
Yang Tse 13 years ago
parent 8b79584e01
commit 4980cc99e2
1 changed files with 157 additions and 177 deletions
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  1. 288
      ares_init.c

288
ares_init.c
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@ -65,11 +65,11 @@
#endif
#include "ares.h"
#include "inet_ntop.h"
#include "inet_net_pton.h"
#include "ares_library_init.h"
#include "ares_nowarn.h"
#include "ares_platform.h"
#include "inet_ntop.h"
#include "ares_private.h"
#ifdef WATT32
@ -598,203 +598,183 @@ static int get_res_interfaces_nt(HKEY hKey, const char *subkey, char **obuf)
return 0;
}
/**
* The desired output for this method is that we set "ret_buf" to
* something like:
*
* 192.168.0.1,dns01.my.domain,fe80::200:f8ff:fe21:67cf
*
* The only ordering requirement is that primary servers are listed
* before secondary. There is no requirement that IPv4 addresses should
* necessarily be before IPv6.
*
* Note that ret_size should ideally be big enough to hold around
* 2-3 IPv4 and 2-3 IPv6 addresses.
*
* Finally, we need to return the total number of DNS servers located.
*/
static int get_iphlpapi_dns_info (char *ret_buf, size_t ret_size)
/* get_iphlpapi_dns_classic() is supported on W98 and newer */
static int get_iphlpapi_dns_classic(char *ret_buf, size_t ret_size)
{
const size_t ipv4_size = INET_ADDRSTRLEN + 1; /* +1 for ',' at end */
const size_t ipv6_size = INET6_ADDRSTRLEN + 12; /* +12 for "%0123456789," */
long left = ret_size;
char *ret = ret_buf;
FIXED_INFO *fi, *newfi;
struct ares_addr namesrvr;
char *txtaddr;
IP_ADDR_STRING *ipAddr;
size_t txtlen;
HRESULT res;
DWORD size = sizeof (*fi);
char *endptr = ret_buf;
int count = 0;
/* Use the GetAdaptersAddresses method if it's available, otherwise
fall back to GetNetworkParams. */
if (ares_fpGetAdaptersAddresses != ZERO_NULL)
{
const ULONG working_buf_size = 15000;
IP_ADAPTER_ADDRESSES *pFirstEntry = NULL;
IP_ADAPTER_ADDRESSES *pEntry = NULL;
ULONG bufSize = 0;
ULONG result = 0;
/* According to MSDN, the recommended way to do this is to use a temporary
buffer of 15K, to "dramatically reduce the chance that the
GetAdaptersAddresses method returns ERROR_BUFFER_OVERFLOW" */
pFirstEntry = (IP_ADAPTER_ADDRESSES *) malloc(working_buf_size);
bufSize = working_buf_size;
if(!pFirstEntry)
return 0;
*endptr = '\0';
/* Call the method one time */
result = (*ares_fpGetAdaptersAddresses)(AF_UNSPEC, 0, 0, pFirstEntry,
&bufSize);
if(result == ERROR_BUFFER_OVERFLOW)
{
/* Reallocate, bufSize should now be set to the required size */
pFirstEntry = (IP_ADAPTER_ADDRESSES *) realloc(pFirstEntry, bufSize);
if(!pFirstEntry)
fi = malloc(size);
if (!fi)
return 0;
/* Call the method a second time */
result = (*ares_fpGetAdaptersAddresses)(AF_UNSPEC, 0, 0, pFirstEntry,
&bufSize);
if(result == ERROR_BUFFER_OVERFLOW)
{
/* Reallocate, bufSize should now be set to the required size */
pFirstEntry = (IP_ADAPTER_ADDRESSES *)realloc(pFirstEntry, bufSize);
if(!pFirstEntry)
return 0;
res = (*ares_fpGetNetworkParams) (fi, &size);
if ((res != ERROR_BUFFER_OVERFLOW) && (res != ERROR_SUCCESS))
goto quit;
/* Call the method a third time. The maximum number of times we're
going to do this is 3. Three shall be the number thou shalt count,
and the number of the counting shall be three. Five is right
out. */
result = (*ares_fpGetAdaptersAddresses)(AF_UNSPEC, 0, 0, pFirstEntry,
&bufSize);
}
}
newfi = realloc(fi, size);
if (!newfi)
goto quit;
/* Check the current result for failure */
if(result != ERROR_SUCCESS)
{
free(pFirstEntry);
return 0;
}
fi = newfi;
res = (*ares_fpGetNetworkParams) (fi, &size);
if (res != ERROR_SUCCESS)
goto quit;
/* process the results */
for(pEntry = pFirstEntry ; pEntry != NULL ; pEntry = pEntry->Next)
{
IP_ADAPTER_DNS_SERVER_ADDRESS* pDNSAddr = pEntry->FirstDnsServerAddress;
for(; pDNSAddr != NULL ; pDNSAddr = pDNSAddr->Next)
for (ipAddr = &fi->DnsServerList; ipAddr; ipAddr = ipAddr->Next)
{
struct sockaddr *pGenericAddr = pDNSAddr->Address.lpSockaddr;
size_t stringlen = 0;
txtaddr = &ipAddr->IpAddress.String[0];
if(pGenericAddr->sa_family == AF_INET && left > ipv4_size)
/* Validate converting textual address to binary format. */
if (ares_inet_pton(AF_INET, txtaddr, &namesrvr.addrV4) == 1)
{
/* Handle the v4 case */
struct sockaddr_in *pIPv4Addr = (struct sockaddr_in *) pGenericAddr;
ares_inet_ntop(AF_INET, &pIPv4Addr->sin_addr, ret,
ipv4_size - 1); /* -1 for comma */
/* Append a comma to the end, THEN NULL. Should be OK because we
already tested the size at the top of the if statement. */
stringlen = strlen(ret);
ret[ stringlen ] = ',';
ret[ stringlen + 1 ] = '\0';
ret += stringlen + 1;
left -= stringlen + 1;
++count;
if ((namesrvr.addrV4.S_un.S_addr == INADDR_ANY) ||
(namesrvr.addrV4.S_un.S_addr == INADDR_NONE))
continue;
}
else if(pGenericAddr->sa_family == AF_INET6 && left > ipv6_size)
else if (ares_inet_pton(AF_INET6, txtaddr, &namesrvr.addrV6) == 1)
{
/* Handle the v6 case */
struct sockaddr_in6 *pIPv6Addr = (struct sockaddr_in6 *)pGenericAddr;
ares_inet_ntop(AF_INET6, &pIPv6Addr->sin6_addr, ret,
ipv6_size - 1); /* -1 for comma */
/* Append a comma to the end, THEN NULL. Should be OK because we
already tested the size at the top of the if statement. */
stringlen = strlen(ret);
ret[ stringlen ] = ',';
ret[ stringlen + 1 ] = '\0';
ret += stringlen + 1;
left -= stringlen + 1;
++count;
/* NB on Windows this also returns stuff in the fec0::/10 range,
seems to be hard-coded somehow. Do we need to ignore them? */
if (memcmp(&namesrvr.addrV6, &ares_in6addr_any,
sizeof(namesrvr.addrV6)) == 0)
continue;
}
else
continue;
txtlen = strlen(txtaddr);
if (ret_size >= strlen(ret_buf) + txtlen + 2)
{
sprintf(endptr, "%s,", txtaddr);
endptr += txtlen + 1;
count++;
}
}
if(pFirstEntry)
free(pFirstEntry);
if (ret > ret_buf)
ret[-1] = '\0';
quit:
if (fi)
free(fi);
if (endptr != ret_buf)
*(endptr - 1) = '\0';
return count;
}
else
#define IPAA_INITIAL_BUF_SZ 15 * 1024
#define IPAA_MAX_TRIES 3
static int get_iphlpapi_dns_info(char *ret_buf, size_t ret_size)
{
FIXED_INFO *fi, *newfi;
DWORD size = sizeof (*fi);
IP_ADDR_STRING *ipAddr;
int i;
int debug = 0;
HRESULT res;
IP_ADAPTER_DNS_SERVER_ADDRESS *ipaDNSAddr;
IP_ADAPTER_ADDRESSES *ipaa, *newipaa, *ipaaEntry;
ULONG res;
ULONG ReqBufsz = IPAA_INITIAL_BUF_SZ;
ULONG Bufsz = IPAA_INITIAL_BUF_SZ;
ULONG AddrFlags = 0;
char *endptr = ret_buf;
int trying = IPAA_MAX_TRIES;
int count = 0;
fi = malloc(size);
if (!fi)
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")];
size_t txtlen;
/* Unless GetAdaptersAddresses is available, use GetNetworkParams */
if (ares_fpGetAdaptersAddresses == ZERO_NULL)
return get_iphlpapi_dns_classic(ret_buf, ret_size);
*endptr = '\0';
ipaa = malloc(Bufsz);
if (!ipaa)
return 0;
res = (*ares_fpGetNetworkParams) (fi, &size);
/* Usually this call suceeds with initial buffer size */
res = (*ares_fpGetAdaptersAddresses) (AF_UNSPEC, AddrFlags, NULL,
ipaa, &ReqBufsz);
if ((res != ERROR_BUFFER_OVERFLOW) && (res != ERROR_SUCCESS))
goto quit;
newfi = realloc(fi, size);
if (!newfi)
while ((res == ERROR_BUFFER_OVERFLOW) && (--trying))
{
if (Bufsz < ReqBufsz)
{
newipaa = realloc(ipaa, ReqBufsz);
if (!newipaa)
goto quit;
fi = newfi;
res = (*ares_fpGetNetworkParams) (fi, &size);
Bufsz = ReqBufsz;
ipaa = newipaa;
}
res = (*ares_fpGetAdaptersAddresses) (AF_UNSPEC, AddrFlags, NULL,
ipaa, &ReqBufsz);
if (res == ERROR_SUCCESS)
break;
}
if (res != ERROR_SUCCESS)
goto quit;
if (debug)
for (ipaaEntry = ipaa; ipaaEntry; ipaaEntry = ipaaEntry->Next)
{
for (ipaDNSAddr = ipaaEntry->FirstDnsServerAddress;
ipaDNSAddr;
ipaDNSAddr = ipaDNSAddr->Next)
{
printf ("Host Name: %s\n", fi->HostName);
printf ("Domain Name: %s\n", fi->DomainName);
printf ("DNS Servers:\n"
" %s (primary)\n", fi->DnsServerList.IpAddress.String);
namesrvr.sa = ipaDNSAddr->Address.lpSockaddr;
if (namesrvr.sa->sa_family == AF_INET)
{
if ((namesrvr.sa4->sin_addr.S_un.S_addr == INADDR_ANY) ||
(namesrvr.sa4->sin_addr.S_un.S_addr == INADDR_NONE))
continue;
if (! ares_inet_ntop(AF_INET, &namesrvr.sa4->sin_addr,
txtaddr, sizeof(txtaddr)))
continue;
}
if (strlen(fi->DnsServerList.IpAddress.String) > 0 &&
inet_addr(fi->DnsServerList.IpAddress.String) != INADDR_NONE &&
left > ipv4_size)
else if (namesrvr.sa->sa_family == AF_INET6)
{
ret += sprintf (ret, "%s,", fi->DnsServerList.IpAddress.String);
left -= ret - ret_buf;
++count;
if (memcmp(&namesrvr.sa6->sin6_addr, &ares_in6addr_any,
sizeof(namesrvr.sa6->sin6_addr)) == 0)
continue;
if (! ares_inet_ntop(AF_INET, &namesrvr.sa6->sin6_addr,
txtaddr, sizeof(txtaddr)))
continue;
}
else
continue;
for (i = 0, ipAddr = fi->DnsServerList.Next; ipAddr && left > ipv4_size;
ipAddr = ipAddr->Next, i++)
{
if (inet_addr(ipAddr->IpAddress.String) != INADDR_NONE)
txtlen = strlen(txtaddr);
if (ret_size >= strlen(ret_buf) + txtlen + 2)
{
ret += sprintf (ret, "%s,", ipAddr->IpAddress.String);
left -= ret - ret_buf;
++count;
sprintf(endptr, "%s,", txtaddr);
endptr += txtlen + 1;
count++;
}
}
if (debug)
printf (" %s (secondary %d)\n", ipAddr->IpAddress.String, i+1);
}
quit:
if (fi)
free(fi);
if (ipaa)
free(ipaa);
if (endptr != ret_buf)
*(endptr - 1) = '\0';
if (debug && left <= ipv4_size)
printf ("Too many nameservers. Truncating to %d addressess", count);
if (ret > ret_buf)
ret[-1] = '\0';
return count;
}
}
#endif
static int init_by_resolv_conf(ares_channel channel)

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