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dnsmasq_interface.c
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dnsmasq_interface.c
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/* Pi-hole: A black hole for Internet advertisements
* (c) 2017 Pi-hole, LLC (https://pi-hole.net)
* Network-wide ad blocking via your own hardware.
*
* FTL Engine
* dnsmasq interfacing routines
*
* This file is copyright under the latest version of the EUPL.
* Please see LICENSE file for your rights under this license. */
#include "dnsmasq/dnsmasq.h"
#undef __USE_XOPEN
#include "FTL.h"
#include "dnsmasq_interface.h"
#include "shmem.h"
void print_flags(unsigned int flags);
void save_reply_type(unsigned int flags, int queryID, struct timeval response);
unsigned long converttimeval(struct timeval time);
static void block_single_domain_regex(char *domain);
static void detect_blocked_IP(unsigned short flags, char* answer, int queryID);
static void query_externally_blocked(int i);
static int findQueryID(int id);
unsigned char* pihole_privacylevel = &config.privacylevel;
char flagnames[28][12] = {"F_IMMORTAL ", "F_NAMEP ", "F_REVERSE ", "F_FORWARD ", "F_DHCP ", "F_NEG ", "F_HOSTS ", "F_IPV4 ", "F_IPV6 ", "F_BIGNAME ", "F_NXDOMAIN ", "F_CNAME ", "F_DNSKEY ", "F_CONFIG ", "F_DS ", "F_DNSSECOK ", "F_UPSTREAM ", "F_RRNAME ", "F_SERVER ", "F_QUERY ", "F_NOERR ", "F_AUTH ", "F_DNSSEC ", "F_KEYTAG ", "F_SECSTAT ", "F_NO_RR ", "F_IPSET ", "F_NOEXTRA "};
void _FTL_new_query(unsigned int flags, char *name, struct all_addr *addr, char *types, int id, char type, const char* file, const int line)
{
// Don't analyze anything if in PRIVACY_NOSTATS mode
if(config.privacylevel >= PRIVACY_NOSTATS)
return;
// Create new query in data structure
lock_shm();
// Get timestamp
int querytimestamp, overTimetimestamp;
gettimestamp(&querytimestamp, &overTimetimestamp);
// Save request time
struct timeval request;
gettimeofday(&request, 0);
// Determine query type
unsigned char querytype = 0;
if(strcmp(types,"query[A]") == 0)
querytype = TYPE_A;
else if(strcmp(types,"query[AAAA]") == 0)
querytype = TYPE_AAAA;
else if(strcmp(types,"query[ANY]") == 0)
querytype = TYPE_ANY;
else if(strcmp(types,"query[SRV]") == 0)
querytype = TYPE_SRV;
else if(strcmp(types,"query[SOA]") == 0)
querytype = TYPE_SOA;
else if(strcmp(types,"query[PTR]") == 0)
querytype = TYPE_PTR;
else if(strcmp(types,"query[TXT]") == 0)
querytype = TYPE_TXT;
else
{
// Return early to avoid accessing querytypedata out of bounds
if(config.debug & DEBUG_QUERIES) logg("Notice: Skipping unknown query type: %s (%i)", types, id);
unlock_shm();
return;
}
// Skip AAAA queries if user doesn't want to have them analyzed
if(!config.analyze_AAAA && querytype == TYPE_AAAA)
{
if(config.debug & DEBUG_QUERIES) logg("Not analyzing AAAA query");
unlock_shm();
return;
}
// Ensure we have enough space in the queries struct
memory_check(QUERIES);
int queryID = counters->queries;
// Convert domain to lower case
char *domain = strdup(name);
strtolower(domain);
// If domain is "pi.hole" we skip this query
if(strcmp(domain, "pi.hole") == 0)
{
// free memory already allocated here
free(domain);
unlock_shm();
return;
}
// Store plain text domain in buffer for regex validation
char *domainbuffer = strdup(domain);
// Get client IP address
char dest[ADDRSTRLEN];
inet_ntop((flags & F_IPV4) ? AF_INET : AF_INET6, addr, dest, ADDRSTRLEN);
char *client = strdup(dest);
strtolower(client);
// Check if user wants to skip queries coming from localhost
if(config.ignore_localhost &&
(strcmp(client, "127.0.0.1") == 0 || strcmp(client, "::1") == 0))
{
free(domain);
free(client);
unlock_shm();
return;
}
// Log new query if in debug mode
char *proto = (type == UDP) ? "UDP" : "TCP";
if(config.debug & DEBUG_QUERIES)
logg("**** new %s %s \"%s\" from %s (ID %i, FTL %i, %s:%i)", proto, types, domain, client, id, queryID, file, line);
// Update counters
int timeidx = findOverTimeID(overTimetimestamp);
validate_access("overTime", timeidx, true, __LINE__, __FUNCTION__, __FILE__);
overTime[timeidx].querytypedata[querytype-1]++;
counters->querytype[querytype-1]++;
// Skip rest of the analysis if this query is not of type A or AAAA
// but user wants to see only A and AAAA queries (pre-v4.1 behavior)
if(config.analyze_only_A_AAAA && querytype != TYPE_A && querytype != TYPE_AAAA)
{
// Don't process this query further here, we already counted it
if(config.debug & DEBUG_QUERIES) logg("Notice: Skipping new query: %s (%i)", types, id);
free(domain);
free(domainbuffer);
free(client);
unlock_shm();
return;
}
// Go through already knows domains and see if it is one of them
int domainID = findDomainID(domain);
// Go through already knows clients and see if it is one of them
int clientID = findClientID(client, true);
// Save everything
validate_access("queries", queryID, false, __LINE__, __FUNCTION__, __FILE__);
queries[queryID].magic = MAGICBYTE;
queries[queryID].timestamp = querytimestamp;
queries[queryID].type = querytype;
queries[queryID].status = QUERY_UNKNOWN;
queries[queryID].domainID = domainID;
queries[queryID].clientID = clientID;
queries[queryID].timeidx = timeidx;
// Initialize database rowID with zero, will be set when the query is stored in the long-term DB
queries[queryID].db = 0;
queries[queryID].id = id;
queries[queryID].complete = false;
queries[queryID].response = converttimeval(request);
// Initialize reply type
queries[queryID].reply = REPLY_UNKNOWN;
// Store DNSSEC result for this domain
queries[queryID].dnssec = DNSSEC_UNSPECIFIED;
// Check and apply possible privacy level rules
// The currently set privacy level (at the time the query is
// generated) is stored in the queries structure
get_privacy_level(NULL);
queries[queryID].privacylevel = config.privacylevel;
// Increase DNS queries counter
counters->queries++;
// Count this query as unknown as long as no reply has
// been found and analyzed
counters->unknown++;
// Update overTime data
validate_access("overTime", timeidx, true, __LINE__, __FUNCTION__, __FILE__);
overTime[timeidx].total++;
// Update overTime data structure with the new client
overTimeClientData[clientID][timeidx]++;
// Set lastQuery timer and add one query for network table
clients[clientID].lastQuery = querytimestamp;
clients[clientID].numQueriesARP++;
// Try blocking regex if configured
validate_access("domains", domainID, false, __LINE__, __FUNCTION__, __FILE__);
if(domains[domainID].regexmatch == REGEX_UNKNOWN && blockingstatus != BLOCKING_DISABLED)
{
// For minimal performance impact, we test the regex only when
// - regex checking is enabled, and
// - this domain has not already been validated against the regex.
// This effectively prevents multiple evaluations of the same domain
//
// If a regex filter matched, we additionally compare the domain
// against all known whitelisted domains to possibly prevent blocking
// of a specific domain. The logic herein is:
// If matched, then compare against whitelist
// If in whitelist, negate matched so this function returns: not-to-be-blocked
if(match_regex(domainbuffer) && !in_whitelist(domainbuffer))
{
// We have to block this domain
block_single_domain_regex(domainbuffer);
domains[domainID].regexmatch = REGEX_BLOCKED;
}
else
{
// Explicitly mark as not blocked to skip regex test
// next time we see this domain
domains[domainID].regexmatch = REGEX_NOTBLOCKED;
}
}
// Free allocated memory
free(client);
free(domain);
free(domainbuffer);
// Release thread lock
unlock_shm();
}
static int findQueryID(int id)
{
// Loop over all queries - we loop in reverse order (start from the most recent query and
// continuously walk older queries while trying to find a match. Ideally, we should always
// find the correct query with zero iterations, but it may happen that queries are processed
// asynchronously, e.g. for slow upstream relies to a huge amount of requests.
// We iterate from the most recent query down to at most MAXITER queries in the past to avoid
// iterating through the entire array of queries
// MAX(0, a) is used to return 0 in case a is negative (negative array indices are harmful)
// Validate access only once for the maximum index (all lower will work)
validate_access("queries", counters->queries-1, false, __LINE__, __FUNCTION__, __FILE__);
int until = MAX(0, counters->queries-MAXITER);
int start = MAX(0, counters->queries-1);
// Check UUIDs of queries
for(int i = start; i >= until; i--)
if(queries[i].id == id)
return i;
// If not found
return -1;
}
void _FTL_forwarded(unsigned int flags, char *name, struct all_addr *addr, int id, const char* file, const int line)
{
// Don't analyze anything if in PRIVACY_NOSTATS mode
if(config.privacylevel >= PRIVACY_NOSTATS)
return;
// Save that this query got forwarded to an upstream server
lock_shm();
// Get forward destination IP address
char dest[ADDRSTRLEN];
if(addr != NULL)
inet_ntop((flags & F_IPV4) ? AF_INET : AF_INET6, addr, dest, ADDRSTRLEN);
// Convert forward to lower case
char *forward = strdup(dest);
strtolower(forward);
// Debug logging
if(config.debug & DEBUG_QUERIES) logg("**** forwarded %s to %s (ID %i, %s:%i)", name, forward, id, file, line);
// Save status and forwardID in corresponding query identified by dnsmasq's ID
int i = findQueryID(id);
if(i < 0)
{
// This may happen e.g. if the original query was a PTR query or "pi.hole"
// as we ignore them altogether
free(forward);
unlock_shm();
return;
}
// Proceed only if
// - current query has not been marked as replied to so far
// (it could be that answers from multiple forward
// destinations are coming in for the same query)
// - the query was formally known as cached but had to be forwarded
// (this is a special case further described below)
if(queries[i].complete && queries[i].status != QUERY_CACHE)
{
free(forward);
unlock_shm();
return;
}
// Get ID of forward destination, create new forward destination record
// if not found in current data structure
int forwardID = findForwardID(forward, true);
queries[i].forwardID = forwardID;
int j = queries[i].timeidx;
validate_access("overTime", j, true, __LINE__, __FUNCTION__, __FILE__);
if(queries[i].status == QUERY_CACHE)
{
// Detect if we cached the <CNAME> but need to ask the upstream
// servers for the actual IPs now, we remove this query from the
// counters for cache replied queries as we had to forward a
// request for it. Example:
// Assume a domain a.com is a CNAME which is cached and has a very
// long TTL. It point to another domain server.a.com which has an
// A record but this has a much lower TTL.
// If you now query a.com and then again after some time, you end
// up in a situation where dnsmasq can answer the first level of
// the DNS result (the CNAME) from cache, hence the status of this
// query is marked as "answered from cache" in FTLDNS. However, for
// server.a.com wit the much shorter TTL, we still have to forward
// something and ask the upstream server for the final IP address.
// This code section acknowledges this by removing one entry from
// the cached counters as we will re-brand this query as having been
// forwarded in the following.
counters->cached--;
// Also correct overTime data
overTime[j].cached--;
// Correct reply timer
struct timeval response;
gettimeofday(&response, 0);
// Reset timer, shift slightly into the past to acknowledge the time
// FTLDNS needed to look up the CNAME in its cache
queries[i].response = converttimeval(response) - queries[i].response;
}
else
{
// Normal forwarded query (status is set below)
// Query is no longer unknown
counters->unknown--;
// Hereby, this query is now fully determined
queries[i].complete = true;
}
// Set query status to forwarded only after the
// if(queries[i].status == QUERY_CACHE) { ... }
// from above as otherwise this check will always
// be negative
queries[i].status = QUERY_FORWARDED;
// Update overTime data
overTime[j].forwarded++;
// Update counter for forwarded queries
counters->forwardedqueries++;
// Release allocated memory
free(forward);
unlock_shm();
}
void FTL_dnsmasq_reload(void)
{
// This function is called by the dnsmasq code on receive of SIGHUP
// *before* clearing the cache and rereading the lists
// This is the only hook that is not skipped in PRIVACY_NOSTATS mode
// Called when dnsmasq re-reads its config and hosts files
// Reset number of blocked domains
counters->gravity = 0;
// Inspect 01-pihole.conf to see if Pi-hole blocking is enabled,
// i.e. if /etc/pihole/gravity.list is sourced as addn-hosts file
check_blocking_status();
// Reread pihole-FTL.conf to see which blocking mode the user wants to use
// It is possible to change the blocking mode here as we anyhow clear the
// cache and reread all blocking lists
// Passing NULL to this function means it has to open the config file on
// its own behalf (on initial reading, the config file is already opened)
get_blocking_mode(NULL);
// Reread regex.list
free_regex();
read_regex_from_file();
// Reread pihole-FTL.conf to see which debugging flags are set
read_debuging_settings(NULL);
}
void _FTL_reply(unsigned short flags, char *name, struct all_addr *addr, int id, const char* file, const int line)
{
// Don't analyze anything if in PRIVACY_NOSTATS mode
if(config.privacylevel >= PRIVACY_NOSTATS)
return;
// Interpret hosts files that have been read by dnsmasq
lock_shm();
// Determine returned result if available
char dest[ADDRSTRLEN]; dest[0] = '\0';
if(addr)
{
inet_ntop((flags & F_IPV4) ? AF_INET : AF_INET6, addr, dest, ADDRSTRLEN);
}
// Extract answer (used e.g. for detecting if a local config is a user-defined
// wildcard blocking entry in form "server=/tobeblocked.com/")
char *answer = dest;
if(flags & F_CNAME)
answer = "(CNAME)";
else if((flags & F_NEG) && (flags & F_NXDOMAIN))
answer = "(NXDOMAIN)";
else if(flags & F_NEG)
answer = "(NODATA)";
if(config.debug & DEBUG_QUERIES)
{
logg("**** got reply %s is %s (ID %i, %s:%i)", name, answer, id, file, line);
print_flags(flags);
}
// Get response time
struct timeval response;
gettimeofday(&response, 0);
// Save status in corresponding query identified by dnsmasq's ID
int i = findQueryID(id);
if(i < 0)
{
// This may happen e.g. if the original query was "pi.hole"
if(config.debug & DEBUG_QUERIES) logg("FTL_reply(): Query %i has not been found", id);
unlock_shm();
return;
}
if(queries[i].reply != REPLY_UNKNOWN)
{
// Nothing to be done here
unlock_shm();
return;
}
// Determine if this reply is an exact match for the queried domain
int domainID = queries[i].domainID;
validate_access("domains", domainID, true, __LINE__, __FUNCTION__, __FILE__);
bool isExactMatch = (name != NULL && strcmp(getstr(domains[domainID].domainpos), name) == 0);
if((flags & F_CONFIG) && isExactMatch && !queries[i].complete)
{
// Answered from local configuration, might be a wildcard or user-provided
// This query is no longer unknown
counters->unknown--;
// Get time index
int querytimestamp, overTimetimestamp;
gettimestamp(&querytimestamp, &overTimetimestamp);
int timeidx = findOverTimeID(overTimetimestamp);
validate_access("overTime", timeidx, true, __LINE__, __FUNCTION__, __FILE__);
if(strcmp(answer, "(NXDOMAIN)") == 0 ||
strcmp(answer, "0.0.0.0") == 0 ||
strcmp(answer, "::") == 0)
{
// Answered from user-defined blocking rules (dnsmasq config files)
counters->blocked++;
overTime[timeidx].blocked++;
validate_access("domains", queries[i].domainID, true, __LINE__, __FUNCTION__, __FILE__);
domains[queries[i].domainID].blockedcount++;
validate_access("clients", queries[i].clientID, true, __LINE__, __FUNCTION__, __FILE__);
clients[queries[i].clientID].blockedcount++;
queries[i].status = QUERY_WILDCARD;
}
else
{
// Answered from a custom (user provided) cache file
counters->cached++;
overTime[timeidx].cached++;
queries[i].status = QUERY_CACHE;
}
// Save reply type and update individual reply counters
save_reply_type(flags, i, response);
// Hereby, this query is now fully determined
queries[i].complete = true;
}
else if((flags & F_FORWARD) && isExactMatch)
{
// Only proceed if query is not already known
// to have been blocked by Quad9
if(queries[i].reply != QUERY_EXTERNAL_BLOCKED)
{
// Save reply type and update individual reply counters
save_reply_type(flags, i, response);
// Detect if returned IP indicates that this query was blocked
detect_blocked_IP(flags, answer, i);
}
}
else if(flags & F_REVERSE)
{
// isExactMatch is not used here as the PTR is special.
// Example:
// Question: PTR 8.8.8.8
// will lead to:
// domains[domainID].domain = 8.8.8.8.in-addr.arpa
// and will return
// name = google-public-dns-a.google.com
// Hence, isExactMatch is always false
// Save reply type and update individual reply counters
save_reply_type(flags, i, response);
}
else if(isExactMatch && !queries[i].complete)
{
logg("*************************** unknown REPLY ***************************");
print_flags(flags);
}
unlock_shm();
}
static void detect_blocked_IP(unsigned short flags, char* answer, int queryID)
{
// Skip replies which originated locally. Otherwise, we would count
// gravity.list blocked queries as externally blocked.
if(flags & F_HOSTS)
{
return;
}
// If received one of the following IPs as reply, OpenDNS
// (Cisco Umbrella) blocked this query
// See https://support.opendns.com/hc/en-us/articles/227986927-What-are-the-Cisco-Umbrella-Block-Page-IP-Addresses-
// for a full list of these IP addresses
if(flags & F_IPV4 && answer != NULL &&
(strcmp("146.112.61.104", answer) == 0 ||
strcmp("146.112.61.105", answer) == 0 ||
strcmp("146.112.61.106", answer) == 0 ||
strcmp("146.112.61.107", answer) == 0 ||
strcmp("146.112.61.108", answer) == 0 ||
strcmp("146.112.61.109", answer) == 0 ||
strcmp("146.112.61.110", answer) == 0 ))
{
query_externally_blocked(queryID);
}
else if(flags & F_IPV6 && answer != NULL &&
(strcmp("::ffff:146.112.61.104", answer) == 0 ||
strcmp("::ffff:146.112.61.105", answer) == 0 ||
strcmp("::ffff:146.112.61.106", answer) == 0 ||
strcmp("::ffff:146.112.61.107", answer) == 0 ||
strcmp("::ffff:146.112.61.108", answer) == 0 ||
strcmp("::ffff:146.112.61.109", answer) == 0 ||
strcmp("::ffff:146.112.61.110", answer) == 0 ))
{
query_externally_blocked(queryID);
}
// If upstream replied with 0.0.0.0 or ::,
// we assume that it filtered the reply as
// nothing is reachable under these addresses
else if(flags & F_IPV4 && answer != NULL &&
strcmp("0.0.0.0", answer) == 0)
{
query_externally_blocked(queryID);
}
else if(flags & F_IPV6 && answer != NULL &&
strcmp("::", answer) == 0)
{
query_externally_blocked(queryID);
}
}
static void query_externally_blocked(int i)
{
// If query is already known to be externally blocked,
// then we have nothing to do here
if(queries[i].status == QUERY_EXTERNAL_BLOCKED)
return;
// Correct counters if necessary ...
if(queries[i].status == QUERY_FORWARDED)
{
counters->forwardedqueries--;
overTime[queries[i].timeidx].forwarded--;
validate_access("forwarded", queries[i].forwardID, true, __LINE__, __FUNCTION__, __FILE__);
forwarded[queries[i].forwardID].count--;
}
// ... but as blocked
counters->blocked++;
overTime[queries[i].timeidx].blocked++;
validate_access("domains", queries[i].domainID, true, __LINE__, __FUNCTION__, __FILE__);
domains[queries[i].domainID].blockedcount++;
validate_access("clients", queries[i].clientID, true, __LINE__, __FUNCTION__, __FILE__);
clients[queries[i].clientID].blockedcount++;
queries[i].status = QUERY_EXTERNAL_BLOCKED;
}
void _FTL_cache(unsigned int flags, char *name, struct all_addr *addr, char *arg, int id, const char* file, const int line)
{
// Don't analyze anything if in PRIVACY_NOSTATS mode
if(config.privacylevel >= PRIVACY_NOSTATS)
return;
// Save that this query got answered from cache
lock_shm();
char dest[ADDRSTRLEN]; dest[0] = '\0';
if(addr)
{
inet_ntop((flags & F_IPV4) ? AF_INET : AF_INET6, addr, dest, ADDRSTRLEN);
}
// Convert domain to lower case
char *domain = strdup(name);
strtolower(domain);
// If domain is "pi.hole", we skip this query
if(strcmp(domain, "pi.hole") == 0)
{
// free memory already allocated here
free(domain);
unlock_shm();
return;
}
free(domain);
// Debug logging
if(config.debug & DEBUG_QUERIES)
{
logg("**** got cache answer for %s / %s / %s (ID %i, %s:%i)", name, dest, arg, id, file, line);
print_flags(flags);
}
// Get response time
struct timeval response;
gettimeofday(&response, 0);
if(((flags & F_HOSTS) && (flags & F_IMMORTAL)) ||
((flags & F_NAMEP) && (flags & F_DHCP)) ||
(flags & F_FORWARD) ||
(flags & F_REVERSE) ||
(flags & F_RRNAME))
{
// List data: /etc/pihole/gravity.list, /etc/pihole/black.list, /etc/pihole/local.list, etc.
// or
// DHCP server reply
// or
// regex blocked query
// or
// cached answer to previously forwarded request
// Determine requesttype
unsigned char requesttype = 0;
if(flags & F_HOSTS)
{
if(arg != NULL && strstr(arg, "/gravity.list") != NULL)
requesttype = QUERY_GRAVITY;
else if(arg != NULL && strstr(arg, "/black.list") != NULL)
requesttype = QUERY_BLACKLIST;
else // local.list, hostname.list, /etc/hosts and others
requesttype = QUERY_CACHE;
}
else if((flags & F_NAMEP) && (flags & F_DHCP)) // DHCP server reply
requesttype = QUERY_CACHE;
else if(flags & F_FORWARD) // cached answer to previously forwarded request
requesttype = QUERY_CACHE;
else if(flags & F_REVERSE) // cached answer to reverse request (PTR)
requesttype = QUERY_CACHE;
else if(flags & F_RRNAME) // cached answer to TXT query
requesttype = QUERY_CACHE;
else
{
logg("*************************** unknown CACHE reply (1) ***************************");
print_flags(flags);
}
int i = findQueryID(id);
if(i < 0 || queries[i].complete)
{
// This may happen e.g. if the original query was a PTR query or "pi.hole"
// as we ignore them altogether or if the query is already complete
unlock_shm();
return;
}
// This query is no longer unknown
counters->unknown--;
// Get time index
int querytimestamp, overTimetimestamp;
gettimestamp(&querytimestamp, &overTimetimestamp);
int timeidx = findOverTimeID(overTimetimestamp);
validate_access("overTime", timeidx, true, __LINE__, __FUNCTION__, __FILE__);
int domainID = queries[i].domainID;
validate_access("domains", domainID, true, __LINE__, __FUNCTION__, __FILE__);
int clientID = queries[i].clientID;
validate_access("clients", clientID, true, __LINE__, __FUNCTION__, __FILE__);
// Mark this query as blocked if domain was matched by a regex
if(domains[domainID].regexmatch == REGEX_BLOCKED)
requesttype = QUERY_WILDCARD;
queries[i].status = requesttype;
// Detect if returned IP indicates that this query was blocked
detect_blocked_IP(flags, dest, i);
// Re-read requesttype as detect_blocked_IP() might have changed it
requesttype = queries[i].status;
// Handle counters accordingly
switch(requesttype)
{
case QUERY_GRAVITY: // gravity.list
case QUERY_BLACKLIST: // black.list
case QUERY_WILDCARD: // regex blocked
counters->blocked++;
overTime[timeidx].blocked++;
domains[domainID].blockedcount++;
clients[clientID].blockedcount++;
break;
case QUERY_CACHE: // cached from one of the lists
counters->cached++;
overTime[timeidx].cached++;
break;
case QUERY_EXTERNAL_BLOCKED:
// everything has already been done
// in query_externally_blocked()
break;
}
// Save reply type and update individual reply counters
save_reply_type(flags, i, response);
// Hereby, this query is now fully determined
queries[i].complete = true;
}
else
{
logg("*************************** unknown CACHE reply (2) ***************************");
print_flags(flags);
}
unlock_shm();
}
void _FTL_dnssec(int status, int id, const char* file, const int line)
{
// Don't analyze anything if in PRIVACY_NOSTATS mode
if(config.privacylevel >= PRIVACY_NOSTATS)
return;
// Process DNSSEC result for a domain
lock_shm();
// Search for corresponding query identified by ID
int i = findQueryID(id);
if(i < 0)
{
// This may happen e.g. if the original query was an unhandled query type
unlock_shm();
return;
}
// Debug logging
if(config.debug & DEBUG_QUERIES)
{
int domainID = queries[i].domainID;
validate_access("domains", domainID, true, __LINE__, __FUNCTION__, __FILE__);
logg("**** got DNSSEC details for %s: %i (ID %i, %s:%i)", getstr(domains[domainID].domainpos), status, id, file, line);
}
// Iterate through possible values
if(status == STAT_SECURE)
queries[i].dnssec = DNSSEC_SECURE;
else if(status == STAT_INSECURE)
queries[i].dnssec = DNSSEC_INSECURE;
else
queries[i].dnssec = DNSSEC_BOGUS;
unlock_shm();
}
void _FTL_header_analysis(const unsigned char header4, const unsigned int rcode, const int id, const char* file, const int line)
{
// Don't analyze anything if in PRIVACY_NOSTATS mode
if(config.privacylevel >= PRIVACY_NOSTATS)
return;
// Check if RA bit is unset in DNS header and rcode is NXDOMAIN
// If the response code (rcode) is NXDOMAIN, we may be seeing a response from
// an externally blocked query. As they are not always accompany a necessary
// SOA record, they are not getting added to our cache and, therefore,
// FTL_reply() is never getting called from within the cache routines.
// Hence, we have to store the necessary information about the NXDOMAIN
// reply already here.
if((header4 & 0x80) || rcode != NXDOMAIN)
{
// RA bit is set or rcode is not NXDOMAIN
return;
}
lock_shm();
// Search for corresponding query identified by ID
int queryID = findQueryID(id);
if(queryID < 0)
{
// This may happen e.g. if the original query was an unhandled query type
unlock_shm();
return;
}
if(config.debug & DEBUG_QUERIES)
{
int domainID = queries[queryID].domainID;
validate_access("domains", domainID, true, __LINE__, __FUNCTION__, __FILE__);
logg("**** %s externally blocked (ID %i, FTL %i, %s:%i)", getstr(domains[domainID].domainpos), id, queryID, file, line);
}
// Get response time
struct timeval response;
gettimeofday(&response, 0);
// Store query as externally blocked
query_externally_blocked(queryID);
// Store reply type as replied with NXDOMAIN
save_reply_type(F_NEG | F_NXDOMAIN, queryID, response);
unlock_shm();
}
void print_flags(unsigned int flags)
{
// Debug function, listing resolver flags in clear text
// e.g. "Flags: F_FORWARD F_NEG F_IPV6"
// Only print flags if corresponding debugging flag is set
if(!(config.debug & DEBUG_FLAGS))
return;
unsigned int i;
char *flagstr = calloc(256,sizeof(char));
for(i = 0; i < sizeof(flags)*8; i++)
if(flags & (1u << i))
strcat(flagstr, flagnames[i]);
logg(" Flags: %s", flagstr);
free(flagstr);
}
void save_reply_type(unsigned int flags, int queryID, struct timeval response)
{
// Iterate through possible values
validate_access("queries", queryID, false, __LINE__, __FUNCTION__, __FILE__);
if(flags & F_NEG)
{
if(flags & F_NXDOMAIN)
{
// NXDOMAIN
queries[queryID].reply = REPLY_NXDOMAIN;
counters->reply_NXDOMAIN++;
}
else
{
// NODATA(-IPv6)
queries[queryID].reply = REPLY_NODATA;
counters->reply_NODATA++;
}
}
else if(flags & F_CNAME)
{
// <CNAME>
queries[queryID].reply = REPLY_CNAME;
counters->reply_CNAME++;
}
else if(flags & F_REVERSE)
{
// reserve lookup
queries[queryID].reply = REPLY_DOMAIN;
counters->reply_domain++;
}
else if(flags & F_RRNAME)
{
// TXT query
queries[queryID].reply = REPLY_RRNAME;
}
else
{
// Valid IP
queries[queryID].reply = REPLY_IP;
counters->reply_IP++;
}
// Save response time (relative time)
queries[queryID].response = converttimeval(response) -
queries[queryID].response;
}
pthread_t telnet_listenthreadv4;
pthread_t telnet_listenthreadv6;
pthread_t socket_listenthread;
pthread_t DBthread;
pthread_t GCthread;
pthread_t DNSclientthread;
void FTL_fork_and_bind_sockets(struct passwd *ent_pw)
{
if(daemonmode)
go_daemon();
else
savepid();
// We will use the attributes object later to start all threads in detached mode
pthread_attr_t attr;
// Initialize thread attributes object with default attribute values
pthread_attr_init(&attr);
// When a detached thread terminates, its resources are automatically released back to
// the system without the need for another thread to join with the terminated thread
pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
// Bind to sockets
bind_sockets();
// Start TELNET IPv4 thread
if(ipv4telnet && pthread_create( &telnet_listenthreadv4, &attr, telnet_listening_thread_IPv4, NULL ) != 0)
{
logg("Unable to open IPv4 telnet listening thread. Exiting...");
exit(EXIT_FAILURE);
}
// Start TELNET IPv6 thread
if(ipv6telnet && pthread_create( &telnet_listenthreadv6, &attr, telnet_listening_thread_IPv6, NULL ) != 0)
{
logg("Unable to open IPv6 telnet listening thread. Exiting...");
exit(EXIT_FAILURE);
}
// Start SOCKET thread
if(pthread_create( &socket_listenthread, &attr, socket_listening_thread, NULL ) != 0)
{
logg("Unable to open Unix socket listening thread. Exiting...");
exit(EXIT_FAILURE);
}
// Start database thread if database is used
if(database && pthread_create( &DBthread, &attr, DB_thread, NULL ) != 0)
{
logg("Unable to open database thread. Exiting...");
exit(EXIT_FAILURE);
}
// Start thread that will stay in the background until garbage collection needs to be done
if(pthread_create( &GCthread, &attr, GC_thread, NULL ) != 0)
{
logg("Unable to open GC thread. Exiting...");
exit(EXIT_FAILURE);
}
// Start thread that will stay in the background until host names needs to be resolved
if(pthread_create( &DNSclientthread, &attr, DNSclient_thread, NULL ) != 0)
{
logg("Unable to open DNS client thread. Exiting...");
exit(EXIT_FAILURE);
}
// Chown files if FTL started as user root but a dnsmasq config option
// states to run as a different user/group (e.g. "nobody")
if(ent_pw != NULL && getuid() == 0)
{
if(chown(FTLfiles.log, ent_pw->pw_uid, ent_pw->pw_gid) == -1)
logg("Setting ownership (%i:%i) of %s failed: %s (%i)", ent_pw->pw_uid, ent_pw->pw_gid, FTLfiles.log, strerror(errno), errno);
if(database && chown(FTLfiles.db, ent_pw->pw_uid, ent_pw->pw_gid) == -1)
logg("Setting ownership (%i:%i) of %s failed: %s (%i)", ent_pw->pw_uid, ent_pw->pw_gid, FTLfiles.db, strerror(errno), errno);
}
}
// int cache_inserted, cache_live_freed are defined in dnsmasq/cache.c
void getCacheInformation(int *sock)
{
ssend(*sock,"cache-size: %i\ncache-live-freed: %i\ncache-inserted: %i\n",
daemon->cachesize,
daemon->metrics[METRIC_DNS_CACHE_LIVE_FREED],
daemon->metrics[METRIC_DNS_CACHE_INSERTED]);
// cache-size is obvious
// It means the resolver handled <cache-inserted> names lookups that needed to be sent to
// upstream severes and that <cache-live-freed> was thrown out of the cache
// before reaching the end of its time-to-live, to make room for a newer name.
// For <cache-live-freed>, smaller is better.
// New queries are always cached. If the cache is full with entries
// which haven't reached the end of their time-to-live, then the entry
// which hasn't been looked up for the longest time is evicted.
}
void _FTL_forwarding_failed(struct server *server, const char* file, const int line)
{
// Don't analyze anything if in PRIVACY_NOSTATS mode
if(config.privacylevel >= PRIVACY_NOSTATS)
return;
// Save that this query got forwarded to an upstream server
lock_shm();