/*
* $Id: dns_internal.c,v 1.61.2.9 2010/02/13 23:48:10 hno Exp $
*
* DEBUG: section 78 DNS lookups; interacts with lib/rfc1035.c
* AUTHOR: Duane Wessels
*
* SQUID Web Proxy Cache http://www.squid-cache.org/
* ----------------------------------------------------------
*
* Squid is the result of efforts by numerous individuals from
* the Internet community; see the CONTRIBUTORS file for full
* details. Many organizations have provided support for Squid's
* development; see the SPONSORS file for full details. Squid is
* Copyrighted (C) 2001 by the Regents of the University of
* California; see the COPYRIGHT file for full details. Squid
* incorporates software developed and/or copyrighted by other
* sources; see the CREDITS file for full details.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
*
*/
#include "squid.h"
/* MS VisualStudio Projects are monolithic, so we need the following
* #ifndef to exclude the internal DNS code from compile process when
* using External DNS process.
*/
#if !USE_DNSSERVERS
#if HAVE_ARPA_NAMESER_H
#include <arpa/nameser.h>
#endif
#if HAVE_RESOLV_H
#include <resolv.h>
#endif
#ifdef _SQUID_WIN32_
#include <windows.h>
#endif
#ifndef _PATH_RESCONF
#define _PATH_RESCONF "/etc/resolv.conf"
#endif
#ifndef NS_DEFAULTPORT
#define NS_DEFAULTPORT 53
#endif
#ifndef NS_MAXDNAME
#define NS_MAXDNAME 1025
#endif
#ifndef MAXDNSRCH
#define MAXDNSRCH 6
#endif
#ifndef RES_MAXNDOTS
#define RES_MAXNDOTS 15
#endif
/* The buffer size required to store the maximum allowed search path */
#ifndef RESOLV_BUFSZ
#define RESOLV_BUFSZ NS_MAXDNAME * MAXDNSRCH + sizeof("search ") + 1
#endif
#define IDNS_MAX_TRIES 20
#define MAX_RCODE 6
#define MAX_ATTEMPT 3
static int RcodeMatrix[MAX_RCODE][MAX_ATTEMPT];
typedef struct _idns_query idns_query;
CBDATA_TYPE(idns_query);
typedef struct _ns ns;
typedef struct _sp sp;
struct _idns_query {
hash_link hash;
rfc1035_query query;
char buf[RESOLV_BUFSZ];
char name[NS_MAXDNAME + 1];
char orig[NS_MAXDNAME + 1];
ssize_t sz;
unsigned short id;
int nsends;
struct timeval start_t;
struct timeval sent_t;
struct timeval queue_t;
dlink_node lru;
IDNSCB *callback;
void *callback_data;
int attempt;
const char *error;
int rcode;
idns_query *queue;
unsigned short domain;
unsigned short do_searchpath;
int tcp_socket;
char *tcp_buffer;
size_t tcp_buffer_size;
size_t tcp_buffer_offset;
};
struct _ns {
struct sockaddr_in S;
int nqueries;
int nreplies;
};
struct _sp {
char domain[NS_MAXDNAME];
int queries;
};
static ns *nameservers = NULL;
static sp *searchpath = NULL;
static int nns = 0;
static int nns_alloc = 0;
static int npc = 0;
static int npc_alloc = 0;
static int ndots = 1;
static dlink_list lru_list;
static int event_queued = 0;
static hash_table *idns_lookup_hash = NULL;
static OBJH idnsStats;
static void idnsAddNameserver(const char *buf);
static void idnsAddPathComponent(const char *buf);
static void idnsFreeNameservers(void);
static void idnsFreeSearchpath(void);
static void idnsParseNameservers(void);
#ifndef _SQUID_MSWIN_
static void idnsParseResolvConf(void);
#endif
#ifdef _SQUID_WIN32_
static void idnsParseWIN32Registry(void);
static void idnsParseWIN32SearchList(const char *);
#endif
static void idnsCacheQuery(idns_query * q);
static void idnsSendQuery(idns_query * q);
static int idnsFromKnownNameserver(struct sockaddr_in *from);
static idns_query *idnsFindQuery(unsigned short id);
static void idnsGrokReply(const char *buf, size_t sz);
static PF idnsRead;
static EVH idnsCheckQueue;
static void idnsTickleQueue(void);
static void idnsRcodeCount(int, int);
static void
idnsAddNameserver(const char *buf)
{
struct in_addr A;
if (!safe_inet_addr(buf, &A)) {
debug(78, 0) ("WARNING: rejecting '%s' as a name server, because it is not a numeric IP address\n", buf);
return;
}
if (A.s_addr == 0) {
debug(78, 0) ("WARNING: Squid does not accept 0.0.0.0 in DNS server specifications.\n");
debug(78, 0) ("Will be using 127.0.0.1 instead, assuming you meant that DNS is running on the same machine\n");
safe_inet_addr("127.0.0.1", &A);
}
if (nns == nns_alloc) {
int oldalloc = nns_alloc;
ns *oldptr = nameservers;
if (nns_alloc == 0)
nns_alloc = 2;
else
nns_alloc <<= 1;
nameservers = xcalloc(nns_alloc, sizeof(*nameservers));
if (oldptr && oldalloc)
xmemcpy(nameservers, oldptr, oldalloc * sizeof(*nameservers));
if (oldptr)
safe_free(oldptr);
}
assert(nns < nns_alloc);
nameservers[nns].S.sin_family = AF_INET;
nameservers[nns].S.sin_port = htons(NS_DEFAULTPORT);
nameservers[nns].S.sin_addr.s_addr = A.s_addr;
debug(78, 3) ("idnsAddNameserver: Added nameserver #%d: %s\n",
nns, inet_ntoa(nameservers[nns].S.sin_addr));
nns++;
}
static void
idnsAddPathComponent(const char *buf)
{
if (npc == npc_alloc) {
int oldalloc = npc_alloc;
sp *oldptr = searchpath;
if (0 == npc_alloc)
npc_alloc = 2;
else
npc_alloc <<= 1;
searchpath = (sp *) xcalloc(npc_alloc, sizeof(*searchpath));
if (oldptr && oldalloc)
xmemcpy(searchpath, oldptr, oldalloc * sizeof(*searchpath));
if (oldptr)
safe_free(oldptr);
}
assert(npc < npc_alloc);
strcpy(searchpath[npc].domain, buf);
debug(78, 3) ("idnsAddPathComponent: Added domain #%d: %s\n",
npc, searchpath[npc].domain);
npc++;
}
static void
idnsFreeNameservers(void)
{
safe_free(nameservers);
nns = nns_alloc = 0;
}
static void
idnsFreeSearchpath(void)
{
safe_free(searchpath);
npc = npc_alloc = 0;
}
static void
idnsParseNameservers(void)
{
wordlist *w;
for (w = Config.dns_nameservers; w; w = w->next) {
debug(78, 1) ("Adding nameserver %s from squid.conf\n", w->key);
idnsAddNameserver(w->key);
}
}
#ifndef _SQUID_MSWIN_
static void
idnsParseResolvConf(void)
{
FILE *fp;
char buf[RESOLV_BUFSZ];
const char *t;
fp = fopen(_PATH_RESCONF, "r");
if (fp == NULL) {
debug(78, 1) ("%s: %s\n", _PATH_RESCONF, xstrerror());
return;
}
#if defined(_SQUID_CYGWIN_)
setmode(fileno(fp), O_TEXT);
#endif
while (fgets(buf, RESOLV_BUFSZ, fp)) {
t = strtok(buf, w_space);
if (NULL == t) {
continue;
} else if (strcasecmp(t, "nameserver") == 0) {
t = strtok(NULL, w_space);
if (NULL == t)
continue;
debug(78, 1) ("Adding nameserver %s from %s\n", t, _PATH_RESCONF);
idnsAddNameserver(t);
} else if (strcasecmp(t, "domain") == 0) {
idnsFreeSearchpath();
t = strtok(NULL, w_space);
if (NULL == t)
continue;
debug(78, 1) ("Adding domain %s from %s\n", t, _PATH_RESCONF);
idnsAddPathComponent(t);
} else if (strcasecmp(t, "search") == 0) {
idnsFreeSearchpath();
while (NULL != t) {
t = strtok(NULL, w_space);
if (NULL == t)
continue;
debug(78, 1) ("Adding domain %s from %s\n", t, _PATH_RESCONF);
idnsAddPathComponent(t);
}
} else if (strcasecmp(t, "options") == 0) {
while (NULL != t) {
t = strtok(NULL, w_space);
if (NULL == t)
continue;
if (strncmp(t, "ndots:", 6) == 0) {
ndots = atoi(t + 6);
if (ndots < 1)
ndots = 1;
if (ndots > RES_MAXNDOTS)
ndots = RES_MAXNDOTS;
debug(78, 1) ("Adding ndots %d from %s\n", ndots, _PATH_RESCONF);
}
}
}
}
fclose(fp);
if (npc == 0 && (t = getMyHostname())) {
t = strchr(t, '.');
if (t)
idnsAddPathComponent(t + 1);
}
}
#endif
#ifdef _SQUID_WIN32_
static void
idnsParseWIN32SearchList(const char *Separator)
{
char *t;
const char *token;
HKEY hndKey;
if (RegOpenKey(HKEY_LOCAL_MACHINE,
"SYSTEM\\CurrentControlSet\\Services\\Tcpip\\Parameters",
&hndKey) == ERROR_SUCCESS) {
DWORD Type = 0;
DWORD Size = 0;
LONG Result;
Result =
RegQueryValueEx(hndKey, "Domain", NULL, &Type, NULL,
&Size);
if (Result == ERROR_SUCCESS && Size) {
t = (char *) xmalloc(Size);
RegQueryValueEx(hndKey, "Domain", NULL, &Type, (LPBYTE) t,
&Size);
debug(78, 1) ("Adding domain %s from Registry\n", t);
idnsAddPathComponent(t);
xfree(t);
}
Result =
RegQueryValueEx(hndKey, "SearchList", NULL, &Type, NULL,
&Size);
if (Result == ERROR_SUCCESS && Size) {
t = (unsigned char *) xmalloc(Size);
RegQueryValueEx(hndKey, "SearchList", NULL, &Type, (LPBYTE) t,
&Size);
token = strtok((char *) t, Separator);
idnsFreeSearchpath();
while (token) {
idnsAddPathComponent(token);
debug(78, 1) ("Adding domain %s from Registry\n", token);
token = strtok(NULL, Separator);
}
xfree(t);
}
RegCloseKey(hndKey);
}
if (npc == 0 && (token = getMyHostname())) {
token = strchr(token, '.');
if (token)
idnsAddPathComponent(token + 1);
}
}
static void
idnsParseWIN32Registry(void)
{
char *t;
char *token;
HKEY hndKey, hndKey2;
switch (WIN32_OS_version) {
case _WIN_OS_WINNT:
/* get nameservers from the Windows NT registry */
if (RegOpenKey(HKEY_LOCAL_MACHINE,
"SYSTEM\\CurrentControlSet\\Services\\Tcpip\\Parameters",
&hndKey) == ERROR_SUCCESS) {
DWORD Type = 0;
DWORD Size = 0;
LONG Result;
Result =
RegQueryValueEx(hndKey, "DhcpNameServer", NULL, &Type, NULL,
&Size);
if (Result == ERROR_SUCCESS && Size) {
t = (unsigned char *) xmalloc(Size);
RegQueryValueEx(hndKey, "DhcpNameServer", NULL, &Type, t,
&Size);
token = strtok((char *) t, ", ");
while (token) {
idnsAddNameserver(token);
debug(78, 1) ("Adding DHCP nameserver %s from Registry\n",
token);
token = strtok(NULL, ", ");
}
xfree(t);
}
Result =
RegQueryValueEx(hndKey, "NameServer", NULL, &Type, NULL, &Size);
if (Result == ERROR_SUCCESS && Size) {
t = (unsigned char *) xmalloc(Size);
RegQueryValueEx(hndKey, "NameServer", NULL, &Type, t, &Size);
token = strtok((char *) t, ", ");
while (token) {
debug(78, 1) ("Adding nameserver %s from Registry\n",
token);
idnsAddNameserver(token);
token = strtok(NULL, ", ");
}
xfree(t);
}
RegCloseKey(hndKey);
}
idnsParseWIN32SearchList(" ");
break;
case _WIN_OS_WIN2K:
case _WIN_OS_WINXP:
case _WIN_OS_WINNET:
case _WIN_OS_WINLON:
case _WIN_OS_WIN7:
/* get nameservers from the Windows 2000 registry */
/* search all interfaces for DNS server addresses */
if (RegOpenKey(HKEY_LOCAL_MACHINE,
"SYSTEM\\CurrentControlSet\\Services\\Tcpip\\Parameters\\Interfaces",
&hndKey) == ERROR_SUCCESS) {
int i;
char keyname[255];
for (i = 0; i < 10; i++) {
if (RegEnumKey(hndKey, i, (char *) &keyname,
255) == ERROR_SUCCESS) {
char newkeyname[255];
strcpy(newkeyname,
"SYSTEM\\CurrentControlSet\\Services\\Tcpip\\Parameters\\Interfaces\\");
strcat(newkeyname, keyname);
if (RegOpenKey(HKEY_LOCAL_MACHINE, newkeyname,
&hndKey2) == ERROR_SUCCESS) {
DWORD Type = 0;
DWORD Size = 0;
LONG Result;
Result =
RegQueryValueEx(hndKey2, "DhcpNameServer", NULL,
&Type, NULL, &Size);
if (Result == ERROR_SUCCESS && Size) {
t = (unsigned char *) xmalloc(Size);
RegQueryValueEx(hndKey2, "DhcpNameServer", NULL,
&Type, t, &Size);
token = strtok((char *) t, ", ");
while (token) {
debug(78, 1)
("Adding DHCP nameserver %s from Registry\n",
token);
idnsAddNameserver(token);
token = strtok(NULL, ", ");
}
xfree(t);
}
Result =
RegQueryValueEx(hndKey2, "NameServer", NULL, &Type,
NULL, &Size);
if (Result == ERROR_SUCCESS && Size) {
t = (unsigned char *) xmalloc(Size);
RegQueryValueEx(hndKey2, "NameServer", NULL, &Type,
t, &Size);
token = strtok((char *) t, ", ");
while (token) {
debug(78, 1) ("Adding nameserver %s from Registry\n",
token);
idnsAddNameserver(token);
token = strtok(NULL, ", ");
}
xfree(t);
}
RegCloseKey(hndKey2);
}
}
}
RegCloseKey(hndKey);
}
idnsParseWIN32SearchList(", ");
break;
case _WIN_OS_WIN95:
case _WIN_OS_WIN98:
case _WIN_OS_WINME:
/* get nameservers from the Windows 9X registry */
if (RegOpenKey(HKEY_LOCAL_MACHINE,
"SYSTEM\\CurrentControlSet\\Services\\VxD\\MSTCP",
&hndKey) == ERROR_SUCCESS) {
DWORD Type = 0;
DWORD Size = 0;
LONG Result;
Result =
RegQueryValueEx(hndKey, "NameServer", NULL, &Type, NULL, &Size);
if (Result == ERROR_SUCCESS && Size) {
t = (unsigned char *) xmalloc(Size);
RegQueryValueEx(hndKey, "NameServer", NULL, &Type, t, &Size);
token = strtok((char *) t, ", ");
while (token) {
debug(78, 1) ("Adding nameserver %s from Registry\n",
token);
idnsAddNameserver(token);
token = strtok(NULL, ", ");
}
xfree(t);
}
RegCloseKey(hndKey);
}
break;
default:
debug(78, 1)
("Failed to read nameserver from Registry: Unknown System Type.\n");
return;
}
}
#endif
static void
idnsStats(StoreEntry * sentry)
{
dlink_node *n;
idns_query *q;
int i;
int j;
storeAppendPrintf(sentry, "Internal DNS Statistics:\n");
storeAppendPrintf(sentry, "\nThe Queue:\n");
storeAppendPrintf(sentry, " DELAY SINCE\n");
storeAppendPrintf(sentry, " ID SIZE SENDS FIRST SEND LAST SEND\n");
storeAppendPrintf(sentry, "------ ---- ----- ---------- ---------\n");
for (n = lru_list.head; n; n = n->next) {
q = n->data;
storeAppendPrintf(sentry, "%#06x %4d %5d %10.3f %9.3f\n",
(int) q->id, (int) q->sz, q->nsends,
tvSubDsec(q->start_t, current_time),
tvSubDsec(q->sent_t, current_time));
}
storeAppendPrintf(sentry, "\nNameservers:\n");
storeAppendPrintf(sentry, "IP ADDRESS # QUERIES # REPLIES\n");
storeAppendPrintf(sentry, "--------------- --------- ---------\n");
for (i = 0; i < nns; i++) {
storeAppendPrintf(sentry, "%-15s %9d %9d\n",
inet_ntoa(nameservers[i].S.sin_addr),
nameservers[i].nqueries,
nameservers[i].nreplies);
}
storeAppendPrintf(sentry, "\nRcode Matrix:\n");
storeAppendPrintf(sentry, "RCODE");
for (i = 0; i < MAX_ATTEMPT; i++)
storeAppendPrintf(sentry, " ATTEMPT%d", i + 1);
storeAppendPrintf(sentry, "\n");
for (j = 0; j < MAX_RCODE; j++) {
storeAppendPrintf(sentry, "%5d", j);
for (i = 0; i < MAX_ATTEMPT; i++)
storeAppendPrintf(sentry, " %8d", RcodeMatrix[j][i]);
storeAppendPrintf(sentry, "\n");
}
if (npc) {
storeAppendPrintf(sentry, "\nSearch list:\n");
for (i = 0; i < npc; i++)
storeAppendPrintf(sentry, "%s\n", searchpath[i].domain);
storeAppendPrintf(sentry, "\n");
}
}
static void
idnsTickleQueue(void)
{
if (event_queued)
return;
if (NULL == lru_list.tail)
return;
eventAdd("idnsCheckQueue", idnsCheckQueue, NULL, 1.0, 1);
event_queued = 1;
}
static void
idnsTcpCleanup(idns_query * q)
{
if (q->tcp_socket != -1) {
comm_close(q->tcp_socket);
q->tcp_socket = -1;
}
if (q->tcp_buffer) {
memFreeBuf(q->tcp_buffer_size, q->tcp_buffer);
q->tcp_buffer = NULL;
}
}
static void
idnsSendQuery(idns_query * q)
{
int x;
int ns;
if (DnsSocket < 0) {
debug(78, 1) ("idnsSendQuery: Can't send query, no DNS socket!\n");
return;
}
/* XXX Select nameserver */
assert(nns > 0);
assert(q->lru.next == NULL);
assert(q->lru.prev == NULL);
idnsTcpCleanup(q);
try_again:
ns = q->nsends % nns;
x = comm_udp_sendto(DnsSocket,
&nameservers[ns].S,
sizeof(nameservers[ns].S),
q->buf,
q->sz);
q->nsends++;
q->queue_t = q->sent_t = current_time;
if (x < 0) {
debug(50, 1) ("idnsSendQuery: FD %d: sendto: %s\n",
DnsSocket, xstrerror());
if (q->nsends % nns != 0)
goto try_again;
} else {
fd_bytes(DnsSocket, x, FD_WRITE);
commSetSelect(DnsSocket, COMM_SELECT_READ, idnsRead, NULL, 0);
}
nameservers[ns].nqueries++;
dlinkAdd(q, &q->lru, &lru_list);
idnsTickleQueue();
}
static int
idnsFromKnownNameserver(struct sockaddr_in *from)
{
int i;
for (i = 0; i < nns; i++) {
if (nameservers[i].S.sin_addr.s_addr != from->sin_addr.s_addr)
continue;
if (nameservers[i].S.sin_port != from->sin_port)
continue;
return i;
}
return -1;
}
static idns_query *
idnsFindQuery(unsigned short id)
{
dlink_node *n;
idns_query *q;
for (n = lru_list.tail; n; n = n->prev) {
q = n->data;
if (q->id == id)
return q;
}
return NULL;
}
static unsigned short
idnsQueryID(void)
{
unsigned short id = squid_random() & 0xFFFF;
unsigned short first_id = id;
while (idnsFindQuery(id)) {
id++;
if (id == first_id) {
debug(78, 1) ("idnsQueryID: Warning, too many pending DNS requests\n");
break;
}
}
return id;
}
static void
idnsCallback(idns_query * q, rfc1035_rr * answers, int n, const char *error)
{
int valid;
valid = cbdataValid(q->callback_data);
cbdataUnlock(q->callback_data);
if (valid)
q->callback(q->callback_data, answers, n, error);
while (q->queue) {
idns_query *q2 = q->queue;
q->queue = q2->queue;
valid = cbdataValid(q2->callback_data);
cbdataUnlock(q2->callback_data);
if (valid)
q2->callback(q2->callback_data, answers, n, error);
cbdataFree(q2);
}
if (q->hash.key) {
hash_remove_link(idns_lookup_hash, &q->hash);
q->hash.key = NULL;
}
}
static void
idnsReadTcp(int fd, void *data)
{
ssize_t n;
idns_query *q = data;
int ns = (q->nsends - 1) % nns;
if (!q->tcp_buffer)
q->tcp_buffer = memAllocBuf(1024, &q->tcp_buffer_size);
statCounter.syscalls.sock.reads++;
n = FD_READ_METHOD(q->tcp_socket, q->tcp_buffer + q->tcp_buffer_offset, q->tcp_buffer_size - q->tcp_buffer_offset);
if (n < 0 && ignoreErrno(errno)) {
commSetSelect(q->tcp_socket, COMM_SELECT_READ, idnsReadTcp, q, 0);
return;
}
if (n <= 0) {
debug(78, 1) ("idnsReadTcp: Short response from nameserver %d for %s.\n", ns + 1, q->name);
idnsTcpCleanup(q);
return;
}
fd_bytes(fd, n, FD_READ);
q->tcp_buffer_offset += n;
if (q->tcp_buffer_offset > 2) {
unsigned short response_size = ntohs(*(short *) q->tcp_buffer);
if (q->tcp_buffer_offset >= response_size + 2) {
nameservers[ns].nreplies++;
idnsGrokReply(q->tcp_buffer + 2, response_size);
return;
}
if (q->tcp_buffer_size < response_size + 2)
q->tcp_buffer = memReallocBuf(q->tcp_buffer, response_size + 2, &q->tcp_buffer_size);
}
commSetSelect(q->tcp_socket, COMM_SELECT_READ, idnsReadTcp, q, 0);
}
static void
idnsSendTcpQueryDone(int fd, char *bufnotused, size_t size, int errflag, void *data)
{
idns_query *q = data;
if (size > 0)
fd_bytes(fd, size, FD_WRITE);
if (errflag == COMM_ERR_CLOSING)
return;
if (errflag) {
idnsTcpCleanup(q);
return;
}
commSetSelect(q->tcp_socket, COMM_SELECT_READ, idnsReadTcp, q, 0);
}
static void
idnsSendTcpQuery(int fd, int status, void *data)
{
MemBuf buf;
idns_query *q = data;
short nsz;
if (status != COMM_OK) {
int ns = (q->nsends - 1) % nns;
debug(78, 1) ("idnsSendTcpQuery: Failed to connect to DNS server %d using TCP\n", ns + 1);
idnsTcpCleanup(q);
return;
}
memBufInit(&buf, q->sz + 2, q->sz + 2);
nsz = htons(q->sz);
memBufAppend(&buf, &nsz, 2);
memBufAppend(&buf, q->buf, q->sz);
comm_write_mbuf(q->tcp_socket, buf, idnsSendTcpQueryDone, q);
}
static void
idnsRetryTcp(idns_query * q)
{
struct in_addr addr;
int ns = (q->nsends - 1) % nns;
idnsTcpCleanup(q);
if (Config.Addrs.udp_outgoing.s_addr != no_addr.s_addr)
addr = Config.Addrs.udp_outgoing;
else
addr = Config.Addrs.udp_incoming;
q->tcp_socket = comm_open(SOCK_STREAM,
IPPROTO_TCP,
addr,
0,
COMM_NONBLOCKING,
"DNS TCP Socket");
q->queue_t = q->sent_t = current_time;
dlinkAdd(q, &q->lru, &lru_list);
commConnectStart(q->tcp_socket,
inet_ntoa(nameservers[ns].S.sin_addr),
ntohs(nameservers[ns].S.sin_port),
idnsSendTcpQuery,
q
);
}
static void
idnsGrokReply(const char *buf, size_t sz)
{
int n;
rfc1035_message *message = NULL;
idns_query *q;
n = rfc1035MessageUnpack(buf,
sz,
&message);
if (message == NULL) {
debug(78, 2) ("idnsGrokReply: Malformed DNS response\n");
return;
}
debug(78, 3) ("idnsGrokReply: ID %#hx, %d answers\n", message->id, n);
q = idnsFindQuery(message->id);
if (q == NULL) {
debug(78, 3) ("idnsGrokReply: Late response\n");
rfc1035MessageDestroy(message);
return;
}
if (rfc1035QueryCompare(&q->query, message->query) != 0) {
debug(78, 3) ("idnsGrokReply: Query mismatch (%s != %s)\n", q->query.name, message->query->name);
rfc1035MessageDestroy(message);
return;
}
dlinkDelete(&q->lru, &lru_list);
if (message->tc && q->tcp_socket == -1) {
debug(78, 2) ("idnsGrokReply: Response for %s truncated. Retrying using TCP\n", message->query->name);
rfc1035MessageDestroy(message);
idnsRetryTcp(q);
return;
}
idnsRcodeCount(n, q->attempt);
q->error = NULL;
if (n < 0) {
debug(78, 3) ("idnsGrokReply: error %s (%d)\n", rfc1035_error_message, rfc1035_errno);
q->error = rfc1035_error_message;
q->rcode = -n;
if (q->rcode == 2 && ++q->attempt < MAX_ATTEMPT) {
/*
* RCODE 2 is "Server failure - The name server was
* unable to process this query due to a problem with
* the name server."
*/
rfc1035MessageDestroy(message);
q->start_t = current_time;
q->id = idnsQueryID();
rfc1035SetQueryID(q->buf, q->id);
idnsSendQuery(q);
return;
}
if (q->rcode == 3 && q->do_searchpath && q->attempt < MAX_ATTEMPT) {
strcpy(q->name, q->orig);
if (q->domain < npc) {
strcat(q->name, ".");
strcat(q->name, searchpath[q->domain].domain);
debug(78, 3) ("idnsGrokReply: searchpath used for %s\n",
q->name);
q->domain++;
} else {
q->attempt++;
}
rfc1035MessageDestroy(message);
if (q->hash.key) {
hash_remove_link(idns_lookup_hash, &q->hash);
q->hash.key = NULL;
}
q->start_t = current_time;
q->id = idnsQueryID();
rfc1035SetQueryID(q->buf, q->id);
q->sz = rfc1035BuildAQuery(q->name, q->buf, sizeof(q->buf), q->id,
&q->query);
idnsCacheQuery(q);
idnsSendQuery(q);
return;
}
}
idnsCallback(q, message->answer, n, q->error);
rfc1035MessageDestroy(message);
idnsTcpCleanup(q);
cbdataFree(q);
}
static void
idnsRead(int fd, void *data)
{
int *N = &incoming_sockets_accepted;
ssize_t len;
struct sockaddr_in from;
socklen_t from_len;
int max = INCOMING_DNS_MAX;
static char rbuf[SQUID_UDP_SO_RCVBUF];
int ns;
while (max--) {
from_len = sizeof(from);
memset(&from, '\0', from_len);
statCounter.syscalls.sock.recvfroms++;
len = recvfrom(fd, rbuf, sizeof(rbuf), 0, (struct sockaddr *) &from, &from_len);
if (len == 0)
break;
if (len < 0) {
if (ignoreErrno(errno))
break;
#ifdef _SQUID_LINUX_
/* Some Linux systems seem to set the FD for reading and then
* return ECONNREFUSED when sendto() fails and generates an ICMP
* port unreachable message. */
/* or maybe an EHOSTUNREACH "No route to host" message */
if (errno != ECONNREFUSED && errno != EHOSTUNREACH)
#endif
debug(50, 1) ("idnsRead: FD %d recvfrom: %s\n",
fd, xstrerror());
break;
}
fd_bytes(DnsSocket, len, FD_READ);
assert(N);
(*N)++;
debug(78, 3) ("idnsRead: FD %d: received %d bytes from %s.\n",
fd,
(int) len,
inet_ntoa(from.sin_addr));
ns = idnsFromKnownNameserver(&from);
if (ns >= 0) {
nameservers[ns].nreplies++;
} else if (Config.onoff.ignore_unknown_nameservers) {
static time_t last_warning = 0;
if (squid_curtime - last_warning > 60) {
debug(78, 1) ("WARNING: Reply from unknown nameserver [%s]\n",
inet_ntoa(from.sin_addr));
last_warning = squid_curtime;
}
continue;
}
idnsGrokReply(rbuf, len);
}
if (lru_list.head)
commSetSelect(DnsSocket, COMM_SELECT_READ, idnsRead, NULL, 0);
}
static void
idnsCheckQueue(void *unused)
{
dlink_node *n;
dlink_node *p = NULL;
idns_query *q;
event_queued = 0;
if (0 == nns)
/* name servers went away; reconfiguring or shutting down */
return;
for (n = lru_list.tail; n; n = p) {
p = n->prev;
q = n->data;
/* Anything to process in the queue? */
if (tvSubDsec(q->queue_t, current_time) < Config.Timeout.idns_retransmit)
break;
/* Query timer expired? */
if (tvSubDsec(q->sent_t, current_time) < Config.Timeout.idns_retransmit * 1 << ((q->nsends - 1) / nns)) {
dlinkDelete(&q->lru, &lru_list);
q->queue_t = current_time;
dlinkAdd(q, &q->lru, &lru_list);
continue;
}
debug(78, 3) ("idnsCheckQueue: ID %#04x timeout\n",
q->id);
dlinkDelete(&q->lru, &lru_list);
if (tvSubDsec(q->start_t, current_time) < Config.Timeout.idns_query) {
idnsSendQuery(q);
} else {
debug(78, 2) ("idnsCheckQueue: ID %x: giving up after %d tries and %5.1f seconds\n",
(int) q->id, q->nsends,
tvSubDsec(q->start_t, current_time));
if (q->rcode != 0)
idnsCallback(q, NULL, -q->rcode, q->error);
else
idnsCallback(q, NULL, -16, "Timeout");
idnsTcpCleanup(q);
cbdataFree(q);
}
}
idnsTickleQueue();
}
/*
* rcode < 0 indicates an error, rocde >= 0 indicates success
*/
static void
idnsRcodeCount(int rcode, int attempt)
{
if (rcode > 0)
rcode = 0;
else if (rcode < 0)
rcode = -rcode;
if (rcode < MAX_RCODE)
if (attempt < MAX_ATTEMPT)
RcodeMatrix[rcode][attempt]++;
}
/* ====================================================================== */
void
idnsInit(void)
{
static int init = 0;
CBDATA_INIT_TYPE(idns_query);
if (DnsSocket < 0) {
int port;
struct in_addr addr;
if (Config.Addrs.udp_outgoing.s_addr != no_addr.s_addr)
addr = Config.Addrs.udp_outgoing;
else
addr = Config.Addrs.udp_incoming;
DnsSocket = comm_open(SOCK_DGRAM,
IPPROTO_UDP,
addr,
0,
COMM_NONBLOCKING,
"DNS Socket");
if (DnsSocket < 0)
fatal("Could not create a DNS socket");
/* Ouch... we can't call functions using debug from a debug
* statement. Doing so messes up the internal _db_level
*/
port = comm_local_port(DnsSocket);
debug(78, 1) ("DNS Socket created at %s, port %d, FD %d\n",
inet_ntoa(addr),
port, DnsSocket);
}
assert(0 == nns);
idnsParseNameservers();
#ifndef _SQUID_MSWIN_
if (0 == nns)
idnsParseResolvConf();
#endif
#ifdef _SQUID_WIN32_
if (0 == nns)
idnsParseWIN32Registry();
#endif
if (0 == nns) {
debug(78, 1) ("Warning: Could not find any nameservers. Trying to use localhost\n");
#ifdef _SQUID_WIN32_
debug(78, 1) ("Please check your TCP-IP settings or /etc/resolv.conf file\n");
#else
debug(78, 1) ("Please check your /etc/resolv.conf file\n");
#endif
debug(78, 1) ("or use the 'dns_nameservers' option in squid.conf.\n");
idnsAddNameserver("127.0.0.1");
}
if (!init) {
memDataInit(MEM_IDNS_QUERY, "idns_query", sizeof(idns_query), 0);
cachemgrRegister("idns",
"Internal DNS Statistics",
idnsStats, 0, 1);
memset(RcodeMatrix, '\0', sizeof(RcodeMatrix));
idns_lookup_hash = hash_create((HASHCMP *) strcmp, 103, hash_string);
init++;
}
}
void
idnsShutdown(void)
{
if (DnsSocket < 0)
return;
comm_close(DnsSocket);
DnsSocket = -1;
idnsFreeNameservers();
idnsFreeSearchpath();
}
static int
idnsCachedLookup(const char *key, IDNSCB * callback, void *data)
{
idns_query *q;
idns_query *old = hash_lookup(idns_lookup_hash, key);
if (!old)
return 0;
q = cbdataAlloc(idns_query);
q->tcp_socket = -1;
q->callback = callback;
q->callback_data = data;
cbdataLock(q->callback_data);
q->queue = old->queue;
old->queue = q;
return 1;
}
static void
idnsCacheQuery(idns_query * q)
{
q->hash.key = q->query.name;
hash_join(idns_lookup_hash, &q->hash);
}
void
idnsALookup(const char *name, IDNSCB * callback, void *data)
{
unsigned int i;
int nd = 0;
idns_query *q;
if (idnsCachedLookup(name, callback, data))
return;
q = cbdataAlloc(idns_query);
q->tcp_socket = -1;
q->id = idnsQueryID();
for (i = 0; i < strlen(name); i++) {
if (name[i] == '.') {
nd++;
}
}
if (Config.onoff.res_defnames && npc > 0 && name[strlen(name) - 1] != '.') {
q->do_searchpath = 1;
} else {
q->do_searchpath = 0;
}
strcpy(q->orig, name);
strcpy(q->name, q->orig);
if (q->do_searchpath && nd < ndots) {
q->domain = 0;
strcat(q->name, ".");
strcat(q->name, searchpath[q->domain].domain);
debug(78, 3) ("idnsALookup: searchpath used for %s\n",
q->name);
}
q->sz = rfc1035BuildAQuery(q->name, q->buf, sizeof(q->buf), q->id,
&q->query);
if (q->sz < 0) {
/* problem with query data -- query not sent */
callback(data, NULL, 0, "Internal error");
cbdataFree(q);
return;
}
debug(78, 3) ("idnsALookup: buf is %d bytes for %s, id = %#hx\n",
(int) q->sz, q->name, q->id);
q->callback = callback;
q->callback_data = data;
cbdataLock(q->callback_data);
q->start_t = current_time;
idnsCacheQuery(q);
idnsSendQuery(q);
}
void
idnsPTRLookup(const struct in_addr addr, IDNSCB * callback, void *data)
{
idns_query *q;
const char *ip = inet_ntoa(addr);
q = cbdataAlloc(idns_query);
q->tcp_socket = -1;
q->id = idnsQueryID();
q->sz = rfc1035BuildPTRQuery(addr, q->buf, sizeof(q->buf), q->id, &q->query);
debug(78, 3) ("idnsPTRLookup: buf is %d bytes for %s, id = %#hx\n",
(int) q->sz, ip, q->id);
if (q->sz < 0) {
/* problem with query data -- query not sent */
callback(data, NULL, 0, "Internal error");
cbdataFree(q);
return;
}
if (idnsCachedLookup(q->query.name, callback, data)) {
cbdataFree(q);
return;
}
q->callback = callback;
q->callback_data = data;
cbdataLock(q->callback_data);
q->start_t = current_time;
idnsCacheQuery(q);
idnsSendQuery(q);
}
#ifdef SQUID_SNMP
/*
* The function to return the DNS via SNMP
*/
variable_list *
snmp_netIdnsFn(variable_list * Var, snint * ErrP)
{
int i, n = 0;
variable_list *Answer = NULL;
debug(49, 5) ("snmp_netDnsFn: Processing request: \n");
snmpDebugOid(5, Var->name, Var->name_length);
*ErrP = SNMP_ERR_NOERROR;
switch (Var->name[LEN_SQ_NET + 1]) {
case DNS_REQ:
for (i = 0; i < nns; i++)
n += nameservers[i].nqueries;
Answer = snmp_var_new_integer(Var->name, Var->name_length,
n,
SMI_COUNTER32);
break;
case DNS_REP:
for (i = 0; i < nns; i++)
n += nameservers[i].nreplies;
Answer = snmp_var_new_integer(Var->name, Var->name_length,
n,
SMI_COUNTER32);
break;
case DNS_SERVERS:
Answer = snmp_var_new_integer(Var->name, Var->name_length,
nns,
SMI_COUNTER32);
break;
default:
*ErrP = SNMP_ERR_NOSUCHNAME;
break;
}
return Answer;
}
#endif /* SQUID_SNMP */
#endif /* USE_DNSSERVERS */