From 2bb35380238ad0028c6caae1ff0c28b2be1549c0 Mon Sep 17 00:00:00 2001 From: Jan Wagner Date: Wed, 6 Nov 2013 09:45:01 +0100 Subject: [PATCH] Imported Upstream version 1.10 --- LICENSE | 281 ++++++++++++++ README | 74 ++++ configure.pl | 19 + dns_flood_detector.c | 742 +++++++++++++++++++++++++++++++++++++ dns_flood_detector.h | 65 ++++ dnsflood | 36 ++ makefiles/Makefile-BSDI | 11 + makefiles/Makefile-FreeBSD | 11 + makefiles/Makefile-Linux | 11 + makefiles/Makefile-OSX | 11 + makefiles/Makefile-Solaris | 11 + 11 files changed, 1272 insertions(+) create mode 100644 LICENSE create mode 100644 README create mode 100755 configure.pl create mode 100644 dns_flood_detector.c create mode 100644 dns_flood_detector.h create mode 100755 dnsflood create mode 100644 makefiles/Makefile-BSDI create mode 100644 makefiles/Makefile-FreeBSD create mode 100644 makefiles/Makefile-Linux create mode 100644 makefiles/Makefile-OSX create mode 100644 makefiles/Makefile-Solaris diff --git a/LICENSE b/LICENSE new file mode 100644 index 0000000..69e1d93 --- /dev/null +++ b/LICENSE @@ -0,0 +1,281 @@ + GNU GENERAL PUBLIC LICENSE + Version 2, June 1991 + + Copyright (C) 1989, 1991 Free Software Foundation, Inc. + 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + Everyone is permitted to copy and distribute verbatim copies + of this license document, but changing it is not allowed. + + Preamble + + The licenses for most software are designed to take away your +freedom to share and change it. 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DNS Flood Detector is distributed under the +Gnu Public License (see included LICENSE file for details). + +How does it work? + +DNS Flood Detector uses libpcap (in non-promiscuous mode) to monitor +incoming dns queries to a nameserver. The tool may be run in one of two +modes, either daemon mode or "bindsnap" mode. In daemon mode, the tool +will alarm via syslog. In bindsnap mode, the user is able to get +near-real-time stats on usage to aid in more detailed troubleshooting. + +How do I build it? + +Execute ./configure.pl to select the appropriate make target. Then simply +type "make". + +Why was it written? + +I wrote DNS Flood Detector because the fifty or so public recursive +nameservers I am responsible for were being abused by both customers and +non-customers. DNS Flood Detector allows for prompt action when anomalous +conditions are detected. + +What do I need to use it? + +You need libpcap and a little bit of patience. + +What platforms does it work on? + +Linux, BSDI, FreeBSD, Mac OSX, Solaris + +Will it run under Windows {95,98,NT,2000,XP}? + +Maybe. I haven't tried. If it doesn't, feel free to submit a fix. + +What does it look like? + +Usage: ./dns_flood_detector [OPTION] + +-i IFNAME specify interface to listen on +-t N alarm at >N queries per second +-a N reset alarm after N seconds +-w N calculate stats every N seconds +-x N create N buckets +-m N mark total query rate every N seconds +-b run in foreground in bindsnap mode +-d run in background in daemon mode +-v verbose output - use again for more verbosity +-h display this usage information + +Sample Output: + +dopacki:~$ sudo ./dns_flood_detector -v -v -b -t10 +[15:14:56] source [192.168.1.45] - 0 qps tcp : 24 qps udp [8 qps A] [16 +qps PTR] +[15:14:56] source [10.0.24.2] - 0 qps tcp : 15 qps udp [15 qps A] +[15:15:06] source [192.168.1.45] - 0 qps tcp : 24 qps udp [8 qps A] [16 +qps PTR] +[15:15:06] source [10.0.24.2] - 0 qps tcp : 15 qps udp [14 qps A] +[15:15:16] source [192.168.1.45] - 0 qps tcp : 23 qps udp [7 qps A] [15 +qps PTR] + +What if I have questions? + +You can e-mail me at dopacki@adotout.com diff --git a/configure.pl b/configure.pl new file mode 100755 index 0000000..66648ba --- /dev/null +++ b/configure.pl @@ -0,0 +1,19 @@ +#!/usr/bin/perl + +use strict; + +my $os = shift; + +# get target listings +opendir(MAKE_TARGETS,'./makefiles'); +my @targets = grep { /Makefile/ && -f './makefiles/'.$_ && s/^Makefile-// } readdir(MAKE_TARGETS); +closedir(MAKE_TARGETS); + +# display usage +unless ($os && grep{/$os/}@targets) {print< + Date: Tue Mar 18 16:46:53 EST 2003 + Purpose: Monitor DNS servers for abusive usage levels + and alarm to syslog + + compile with: + gcc -o dns_flood_detector -lpcap -lpthread -lm dns_flood_detector.c + + command-line options: + + -i ifname specify interface to listen on (default lets pcap pick) + -t n alarm when more than n queries per second are observed + (default 40) + -a n wait for n seconds before alarming again on same source + (default 90) + -w n calculate statistics every n seconds + (default 10) + -x n use n buckets + (default 50) + -m n mark overall query rate every n seconds + (default disabled) + -b run in foreground in "bindsnap" mode + -d run in background in "daemon" mode + -v detailed information (use twice for more detail) + -h usage info + + Copyright (C) 2003 Dennis Opacki + + 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 02111-1307 USA + + --- new in v1.05 --- + 8/18/2003 - FreeBSD target - Jim Westfall + 8/18/2003 - Moved to getopt(3) for compatibility + 8/19/2003 - Added OSX/BSDI make targets - + Added ability to specify inteface - + + --- new in v1.06 --- + 8/20/2003 - Added Solaris9 make target - + 8/26/2003 - Fixed tcp qdcount bug - + + --- new in v1.07 --- + 8/27/2003 - Fixed alarm reset bug - + 8/28/2003 - Added malloc_fail function - + 8/28/2003 - Added mutex thread locking - + 8/30/2003 - Fixed wierd qtype segfault - + + + --- new in v1.08 --- + 9/02/2003 - Added -v -v output in daemon mode - + + --- new in v1.09 --- + 10/19/2003 - Added stdout flushing to bindsnap mode - + 10/19/2003 - Changed logging priority to LOG_NOTICE - + 10/19/2003 - Fixed low traffic verbose logging bugs - + + --- new in v1.10 --- + 10/22/2003 - Added 'mark status' option via '-m' - + 10/23/2003 - Code cleanup in verbose syslogging - + +********************************************************************************/ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#ifdef __bsdi__ +#include +#else +#ifdef __sun__ +#include +#else +#include +#endif +#endif +#include +#include +#include +#include +#include +#include +#include "dns_flood_detector.h" + +// global variables and their defaults +pthread_mutex_t stats_lock; +struct bucket **bb; +int option_t = 60; +int option_a = 90; +int option_w = 10; +int option_x = 50; +int option_m = 0; +int option_b = 0; +int option_d = 0; +int option_v = 0; +int option_h = 0; +int totals = 0; +char VERSION[] = "1.10"; + +// this is our statistics thread +void *run_stats () { + while (1) { + + // check statistical stuff + pthread_mutex_lock(&stats_lock); + calculate_averages(); + pthread_mutex_unlock(&stats_lock); + + sleep (option_w); + } +} + +// calculate the running average within each bucket +int calculate_averages() { + u_int i,j,delta,cursize,newsize,qps; + char st_time[10]; + time_t now = time(0); + u_int types[] = {1,2,5,6,12,15,252,0}; + u_char *type; + u_char *target; + char *names[] = {"A","NS","CNAME","SOA","PTR","MX","AXFR",""}; + struct tm *raw_time = localtime(&now); + snprintf(st_time, 9, "%02d:%02d:%02d",raw_time->tm_hour,raw_time->tm_min,raw_time->tm_sec); + + for (i=0; iip_addr != NULL ) { + delta = now - bb[i]->first_packet; + + // let's try to avoid a divide-by-zero, shall we? + if (delta > 1 ) { + + // round our average and save it in the bucket + bb[i]->qps = (int)ceil( (float)((((float)bb[i]->tcp_count) + bb[i]->udp_count) / delta)); + + // handle threshold crossing + if ( bb[i]->qps > option_t ) { + + + // display detail to either syslog or stdout + if ( option_b ) { + if ( ! option_v ) { + printf("[%s] source [%s] - %d qps\n",st_time,bb[i]->ip_addr,bb[i]->qps); + fflush(stdout); + } + else { + printf("[%s] source [%s] - %d qps tcp : %d qps udp ",st_time,bb[i]->ip_addr, + (int)ceil( (float)(bb[i]->tcp_count/delta)), + (int)ceil( (float)(bb[i]->udp_count/delta)) + ); + if ( option_v >1 ) { + for (j=0;types[j];j++) { + if ((int)ceil((float)(bb[i]->qstats[types[j]]/delta))){ + printf("[%d qps %s] ",(int)ceil((float)(bb[i]->qstats[types[j]]/delta)),names[j]); + } + } + } + printf("\n"); + fflush(stdout); + } + } + else { + // if running in background, use alarm reset timer + if ((now-bb[i]->alarm_set)>option_a) { + + // display appropriate level of detail via syslog + if ( ! option_v ) { + syslog(LOG_NOTICE,"source [%s] - %d qps\n",bb[i]->ip_addr,bb[i]->qps); + } + else if (option_v > 1) { + target = (char *)malloc(sizeof(char)*MAXSYSLOG); + newsize = MAXSYSLOG; + cursize = snprintf(target,newsize,"source [%s] - %d tcp qps : %d udp qps ",bb[i]->ip_addr, + (int)ceil( (float)(bb[i]->tcp_count/delta)), + (int)ceil( (float)(bb[i]->udp_count/delta)) + ); + newsize-=cursize; + + for (j=0;types[j];j++ ) { + qps = (u_int)ceil((float)(bb[i]->qstats[types[j]]/delta)); + if ( ( qps > 0) && ( newsize > 1 ) ) { + cursize = snprintf(target+(MAXSYSLOG-newsize),newsize,"[%d qps %s] ",qps,names[j]); + newsize-=cursize; + } + } + if (newsize <= 0 ) { + target[MAXSYSLOG-1]='\0'; + } + syslog(LOG_NOTICE,"%s",target); + free(target); + } + else { + syslog(LOG_NOTICE,"source [%s] - %d tcp qps - %d udp qps\n",bb[i]->ip_addr, + (int)ceil( (float)(bb[i]->tcp_count/delta)), + (int)ceil( (float)(bb[i]->udp_count/delta)) + ); + } + + // reset alarm + bb[i]->alarm_set = now; + } + } + } + } + } + } + + // 'mark stats' if required and it is time + delta = now - bb[totals]->first_packet; + if ( (option_m > 0)&&(delta > 1)&&(delta >= option_m) ) { + + // handle bindsnap mode + if (option_b) { + printf("[%s] totals - %d qps tcp : %d qps udp ",st_time,(int)ceil( (float)(bb[totals]->tcp_count/delta)),(int)ceil( (float)(bb[totals]->udp_count/delta))); + if (option_v) { + for (j=0;types[j];j++) { + qps = (u_int)ceil((float)(bb[totals]->qstats[types[j]]/delta)); + if (qps){ + printf("[%d qps %s] ",qps,names[j]); + } + } + } + printf("\n"); + fflush(stdout); + } + else { + // agonizing high verbosity code + if (option_v) { + target = (char *)malloc(sizeof(char)*MAXSYSLOG); + newsize = MAXSYSLOG; + cursize = snprintf(target,newsize,"[totals] - %d tcp qps : %d udp qps ", + (int)ceil( (float)(bb[totals]->tcp_count/delta)), + (int)ceil( (float)(bb[totals]->udp_count/delta)) + ); + newsize-=cursize; + + for (j=0;types[j];j++ ) { + qps = (u_int)ceil((float)(bb[totals]->qstats[types[j]]/delta)); + if ( ( qps > 0) && ( newsize > 1 ) ) { + cursize = snprintf(target+(MAXSYSLOG-newsize),newsize,"[%d qps %s] ",qps,names[j]); + newsize-=cursize; + } + } + if (newsize <= 0 ) { + target[MAXSYSLOG-1]='\0'; + } + syslog(LOG_NOTICE,"%s",target); + free(target); + } + else { + syslog(LOG_NOTICE,"[totals] - %d tcp qps : %d udp qps\n", + (int)ceil( (float)(bb[totals]->tcp_count/delta)), + (int)ceil( (float)(bb[totals]->udp_count/delta)) + ); + } + } + scour_bucket(totals); + } + + return 1; +} + +// purge and initialize all buckets +void init_buckets() { + u_int i; + + // create bucket brigade (final bucket is for totals) + pthread_mutex_lock(&stats_lock); + if ( ( bb = malloc( sizeof(struct bucket *) * (option_x+1)) ) == NULL ) malloc_fail("bb", sizeof(struct bucket *) * (option_x+1)); + for (i=0; i <=option_x; i++ ) { + if ( ( bb[i] = (struct bucket *)malloc( sizeof(struct bucket) ) ) == NULL) malloc_fail("bb[i]", sizeof(struct bucket) ); + bb[i]->ip_addr=NULL; + scour_bucket(i); + } + pthread_mutex_unlock(&stats_lock); +} + +// clean out a bucket while avoiding obvious memory leak +int scour_bucket( int i ) { + int j; + + if ( bb[i]->ip_addr != NULL ) { + free ( bb[i]->ip_addr ); + } + bb[i]->ip_addr=NULL; + bb[i]->tcp_count=0; + bb[i]->udp_count=0; + bb[i]->qps=0; + bb[i]->first_packet=time(0); + bb[i]->last_packet=(time_t)0; + bb[i]->alarm_set=(time_t)0; + + for (j=0;j<256;j++) { + bb[i]->qstats[j]=0; + } + return 1; +} + +// add a packet to a bucket +int add_to_bucket ( char * ip_src, int ip_proto, int num_queries, u_int8_t qtype) { + int bucket = 0; + + // get the bucket to put packet in + pthread_mutex_lock(&stats_lock); + bucket = find_bucket(ip_src); + + // set bucket fields + bb[bucket]->last_packet = time(0); + if (ip_proto == 6 ) { + bb[bucket]->tcp_count+=num_queries; + bb[totals]->tcp_count+=num_queries; + } + else { + bb[bucket]->udp_count+=num_queries; + bb[totals]->udp_count+=num_queries; + } + + bb[bucket]->qstats[qtype]+=num_queries; + bb[totals]->qstats[qtype]+=num_queries; + pthread_mutex_unlock(&stats_lock); + + return 1; +} + +// figure out where to put this packet +int find_bucket(char *ip_src) { + int i, bucket=0; + time_t oldest=0; + + // look for an existing bucket for this IP + for (i=0; i< option_x; i++ ){ + // ip field of bucket is not null and seems to match the ip we are checking + if ((bb[i]->ip_addr != NULL)&&(strncmp(bb[i]->ip_addr, ip_src, strlen(bb[i]->ip_addr))==0)) { + return i; + } + } + + // look for unused buckets + for (i=0; i< option_x; i++ ) { + + // found an unused one - clean it, init it, and return it + if ( bb[i]->ip_addr == NULL ) { + scour_bucket(i); + if ( ( bb[i]->ip_addr = (char *)strdup(ip_src) ) == NULL) malloc_fail("bb[i]->ip_addr", strlen(ip_src) ); + return i; + } + + // find the most stagnant bucket in case we need it + // avoids another loop through the buckets + if ( ( bb[i]->last_packet != 0 ) && ((oldest==0)||( bb[i]->last_packet < oldest))) { + oldest = bb[i]->last_packet; + bucket = i; + } + } + + // use the most stagnant bucket since all are in use + // clean it, init it, and return it + scour_bucket(bucket); + if ( ( bb[bucket]->ip_addr = (char *)strdup(ip_src) ) == NULL) malloc_fail("bb[bucket]->ip_addr", strlen(ip_src) ); + + return bucket; +} + +// handle all packets we throw at it +void handle_IP(u_char *args, const struct pcap_pkthdr* pkthdr,const u_char* packet){ + const struct ip* ip; + const struct my_dns *dns; + const struct tcphdr *tcp; + const struct udphdr *udp; + u_int length = pkthdr->len; + u_int caplen = pkthdr->caplen; + u_int hlen,off,version; + unsigned char dname[NS_MAXDNAME]=""; + char *ip_src; + unsigned char *data; + u_int i,len,dpos; + u_int8_t qtype,qclass,tlen; + + // skip the ethernet header + length -= sizeof(struct ether_header); + + // make sure packet is a valid length + if (length < sizeof(struct ip)) { + return; + } + + // snap off the ip portion + ip = (struct ip*)(packet + sizeof(struct ether_header)); + + // get utility params for sanity checking + len = ntohs(ip->ip_len); + hlen = ip->ip_hl; + version = ip->ip_v; + + // let's not do ipv6 just yet + if(version != 4) { + return; + } + + // make sure we have a sane header length + if(hlen < 5 ) { + return; + } + + // do we have the everything we are supposed to? + if(length < len) { + return; + } + + // make sure we are only processing the first fragment + off = ntohs(ip->ip_off); + if((off & 0x1fff) == 0 ) { + + // get the source ip as a string (probably more efficient to use decimal) + ip_src = (char *)inet_ntoa(ip->ip_src); + + // process udp packets + if ( ip->ip_p == 17 ) { + udp = (struct udphdr *) ( (char *) packet + sizeof(struct ether_header)+ sizeof (struct ip) ); + + // try to make sure it is safe to cast packet into dns structure + if ( (sizeof(struct my_dns)+sizeof(struct ether_header)+sizeof(struct ip)+sizeof(struct udphdr)) >= caplen ) { + return; + } + else { + // populate dns header + dns = (struct my_dns *) ( (char *) packet + sizeof(struct ether_header) + sizeof (struct ip) + sizeof (struct udphdr) ); + data = (char *) packet +sizeof(struct ether_header) + sizeof (struct ip) + sizeof (struct udphdr) + sizeof(struct my_dns); + } + } + + // process tcp packets + else if ( ip->ip_p == 6 ) { + tcp = (struct tcphdr *) ( (char *) packet + sizeof(struct ether_header)+ sizeof (struct ip) ); + + // ignore packets without push flag set + if (! tcp->th_flags & TH_PUSH) return; + + // try to make sure it is safe to cast packet into dns structure + if ( (sizeof(struct my_dns)+sizeof(struct ether_header)+sizeof(struct ip)+(tcp->th_off * sizeof(u_int32_t))) >= caplen ) { + return; + } + else { + // populate dns header + dns = (struct my_dns *) ( (char *) packet + sizeof(struct ether_header)+ sizeof (struct ip) + (tcp->th_off * sizeof(u_int32_t))); + data = (char *) packet + sizeof(struct ether_header) + sizeof (struct ip) + (tcp->th_off * sizeof(u_int32_t)) + sizeof(struct my_dns); + } + } + + // hmm.. not tcp, not udp.. move on. + else { + return; + } + + // we only want queries, not responses + if ( dns->dns_flags1 & 0x80 ) { + return; + } + + // ignore seemingly bogus queries with multiple flags set + if ((ntohs(dns->dns_qdcount)>0)+(ntohs(dns->dns_ancount)>0)+(ntohs(dns->dns_nscount)>0)+(ntohs(dns->dns_arcount)>0)>1 ) { + return; + } + + // get the domain name and query type + tlen=dpos=0; + for (;(*data)&&((void *)data<((void *)packet+caplen-1)); data++) { + if (!tlen) tlen=*data; + for (;(tlen&&((void *)data<((void *)packet+caplen-1)));tlen--){ + data++; + if (dposdns_qdcount)&&qtype) { + add_to_bucket( ip_src, ip->ip_p, 1, qtype ); + } + } + return; +} + +// main logic +// some pcap code borrowed from http://www.cet.nau.edu/~mc8/Socket/Tutorials/section1.html +int main(int argc,char **argv){ + char *dev = NULL; + pthread_t thread; + char errbuf[PCAP_ERRBUF_SIZE]; + pcap_t* descr; + struct bpf_program fp; /* hold compiled program */ + bpf_u_int32 maskp=0; /* subnet mask */ + bpf_u_int32 netp=0; /* ip */ + char *filter = NULL; + char *dst_addr = NULL; + char *dst_mask = NULL; + struct sigaction sa; + struct in_addr addr; + u_int f_size; + char *args = NULL; + u_int c = 0; + + // loop through command line options and get options + while(1) { + int option_index = 0; + c = getopt(argc, argv,"i:t:a:w:x:m:bdvh"); + + if (c==-1) break; + switch(c) { + case 0: + break; + case 'i': + if (optarg) { + if ( ( dev = (char *)strdup(optarg) ) == NULL) malloc_fail("dev", strlen(optarg) ); + } + break; + case 't': + if (optarg) { + if ( abs (atoi(optarg)) > 0) { + option_t = abs( atoi(optarg)); + } + } + break; + case 'a': + if (optarg) { + if ( abs (atoi(optarg)) > 10) { + option_a = abs( atoi(optarg)); + } + } + break; + case 'w': + if (optarg) { + if ( abs (atoi(optarg)) > 1) { + option_w = abs( atoi(optarg)); + } + } + break; + case 'x': + if (optarg) { + if ( abs (atoi(optarg)) > 10) { + option_x = abs( atoi(optarg)); + } + } + break; + case 'm': + if (optarg) { + if ( abs (atoi(optarg)) > 0) { + option_m = abs( atoi(optarg)); + } + } + break; + case 'b': + option_b = 1; + break; + case 'd': + option_d = 1; + break; + case 'v': + option_v++; + break; + case 'h': + option_h = 1; + default: + break; + } + } + + // display usage info if needed + if (optindN queries per second\n"); + fprintf(stderr,"-a N reset alarm after N seconds\n"); + fprintf(stderr,"-w N calculate stats every N seconds\n"); + fprintf(stderr,"-x N create N buckets\n"); + fprintf(stderr,"-m N report overall stats every N seconds\n"); + fprintf(stderr,"-b run in foreground in bindsnap mode\n"); + fprintf(stderr,"-d run in background in daemon mode\n"); + fprintf(stderr,"-v verbose output - use again for more verbosity\n"); + fprintf(stderr,"-h display this usage information\n"); + exit(1); + } + + if ( ( ! option_d ) && ( ! option_b ) ) { + fprintf(stderr,"%s couldn't start\n",argv[0]); + fprintf(stderr,"You must specify either either -d (daemon) or -b (bindsnap)\n"); + exit(1); + } + // set up for daemonized operation unless running in bindsnap mode + if ( ! option_b ) { + openlog("dns_flood_detector",LOG_PID|LOG_CONS,LOG_DAEMON); + syslog(LOG_NOTICE,"dns_flood_detector starting"); + + // daemonize unless running in bindsnap mode + daemonize(); + + // set up signal handlers + sa.sa_handler=exit; + sa.sa_flags=0; + if(sigaction(SIGTERM,&sa,NULL)) { + syslog(LOG_ERR,"Unable to set signal handler: %s. Exiting.", + strerror(errno)); + } + } + + // find a valid device to open + if(dev == NULL && ( (dev=pcap_lookupdev(errbuf)) == NULL ) ){ + fprintf(stderr,"unable to bind to valid device\n"); + exit(1); + } + + // get network address and netmask for device + pcap_lookupnet(dev,&netp,&maskp,errbuf); + + // set up filter with local network + addr.s_addr = (unsigned long int)netp; + if ( ( dst_addr = (char *)malloc( strlen((char *)inet_ntoa(addr))+1) ) == NULL ) malloc_fail("dest_addr", strlen((char *)inet_ntoa(addr))+1 ); + strncpy(dst_addr,(char*)inet_ntoa(addr),strlen((char *)inet_ntoa(addr))); + dst_addr[strlen((char *)inet_ntoa(addr))]='\0'; + + addr.s_addr = (unsigned long int)maskp; + if ( ( dst_mask = (char *)malloc( strlen((char *)inet_ntoa(addr))+1) ) == NULL ) malloc_fail("dest_mask", strlen((char *)inet_ntoa(addr))+1 ); + strncpy(dst_mask,(char*)inet_ntoa(addr),strlen((char *)inet_ntoa(addr))); + dst_mask[strlen((char *)inet_ntoa(addr))]='\0'; + + f_size = strlen("port 53 and dst net mask ")+ strlen(dst_mask)+ strlen(dst_addr); + if ( ( filter = (char *) malloc ( f_size+1) ) == NULL ) malloc_fail( "filter", f_size+1 ); + snprintf( filter, f_size, "port 53 and dst net %s mask %s", dst_addr, dst_mask); + + free (dst_mask); + free (dst_addr); + + // open device for reading only local traffic + descr = pcap_open_live(dev,1500,0,1,errbuf); + if(descr == NULL) { + fprintf(stderr,"unable to open device %s\n",dev); + exit(1); + } + + // compile filter + if(pcap_compile(descr,&fp,filter,0,netp) == -1) { + exit(1); + } + + // set filter + if(pcap_setfilter(descr,&fp) == -1){ + exit(1); + } + + // initialize buckets and mark overall stats bucket + init_buckets(); + totals = option_x; + + // create mutex lock + if (pthread_mutex_init(&stats_lock, NULL) < 0) { + exit(1); + } + + // launch watcher thread + if (pthread_create (&thread, NULL, run_stats, (void *)0)) { + exit(1); + } + + // main pcap loop + pcap_loop(descr,-1,handle_IP,args); + + // done + closelog(); + return 0; +} + +// daemonize the process +int daemonize(void) { + pid_t pid; + int fd; + + fd=open("/dev/null",O_RDWR); + if(fd<0) { + syslog(LOG_ERR,"Failed to open /dev/null: %s. Exiting.",strerror(errno)); + exit(1); + } + + dup2(fd,0); + dup2(fd,1); + dup2(fd,2); + + if((pid=fork())<0) { + syslog(LOG_ERR,"Fork failed: %s. Exiting.",strerror(errno)); + exit(1); + } + else if (pid!=0) { + exit(0); + } + + setsid(); + chdir("/"); + umask(0); + return 0; +} + +int malloc_fail( char * var, int size ) { + // print error to stderr if running in bindsnap mode + if (option_b) { + fprintf(stderr, "our OS wouldn't let me malloc %d bytes for a new %s. giving up", size, var); + } + else { + syslog(LOG_ERR, "our OS wouldn't let me malloc %d bytes for a new %s. giving up", size, var); + } + exit(1); +} diff --git a/dns_flood_detector.h b/dns_flood_detector.h new file mode 100644 index 0000000..b968305 --- /dev/null +++ b/dns_flood_detector.h @@ -0,0 +1,65 @@ +/****************************************************************************** + + Program: dns_flood_detector.h + Author: Dennis Opacki + Date: Tue Mar 18 16:46:53 EST 2003 + Purpose: Monitor DNS servers for abusive usage levels + and alarm to syslog + + Copyright (C) 2003 Dennis Opacki + + 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 02111-1307 USA + +*******************************************************************************/ + +// definitions +#ifndef ETHER_HDRLEN +#define ETHER_HDRLEN 14 +#endif +#define NS_MAXDNAME 1025 +#define MAXSYSLOG 128 + +// evil Solaris hack +#ifdef __sun__ +typedef uint8_t u_int8_t; +typedef uint16_t u_int16_t; +typedef uint32_t u_int32_t; +#endif + +// prototypes +void handle_IP(u_char *args,const struct pcap_pkthdr* pkthdr,const u_char* packet); + +// data structures +struct my_dns { + u_int16_t dns_id; /* query identification number */ + u_int8_t dns_flags1; /* first byte of flags */ + u_int8_t dns_flags2; /* second byte of flags */ + u_int16_t dns_qdcount; /* number of question entries */ + u_int16_t dns_ancount; /* number of answer entries */ + u_int16_t dns_nscount; /* number of authority entries */ + u_int16_t dns_arcount; /* number of resource entries */ +}; + +struct bucket { + char * ip_addr; + unsigned int tcp_count; + unsigned int udp_count; + unsigned int qps; + int qstats[256]; + time_t first_packet; + time_t last_packet; + time_t alarm_set; +}; + diff --git a/dnsflood b/dnsflood new file mode 100755 index 0000000..ebb7584 --- /dev/null +++ b/dnsflood @@ -0,0 +1,36 @@ +#! /bin/sh + +PATH=/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin + +test -f /usr/local/sbin/dns_flood_detector || exit 0 + +case "$1" in + start) + echo -n "Starting DNS flood detector: dns_flood_detector" + start-stop-daemon --start --quiet --exec /usr/local/sbin/dns_flood_detector -- -d + echo "." + ;; + stop) + echo -n "Stopping DNS flood detector: dns_flood_detector" + start-stop-daemon --stop --quiet --exec /usr/local/sbin/dns_flood_detector + killall dns_flood_detector + echo "." + ;; + restart|force-reload) + echo -n "Restarting DNS flood detector: dns_flood_detector... " + start-stop-daemon --stop --quiet --exec /usr/local/sbin/dns_flood_detector + sleep 2 + start-stop-daemon --stop --quiet --exec /usr/local/sbin/dns_flood_detector + sleep 4 + killall dns_flood_detector + sleep 2 + start-stop-daemon --start --quiet --exec /usr/local/sbin/dns_flood_detector -- -d + echo "done." + ;; + *) + echo "Usage: /etc/init.d/dnsflood {start|stop|restart|force-reload}" + exit 1 + ;; +esac + +exit 0 diff --git a/makefiles/Makefile-BSDI b/makefiles/Makefile-BSDI new file mode 100644 index 0000000..c21e536 --- /dev/null +++ b/makefiles/Makefile-BSDI @@ -0,0 +1,11 @@ +CFLAGS+=-O -g +LDLIBS=-lpcap -pthread -lm + +all: dns_flood_detector + strip dns_flood_detector +clean: + rm -rf dns_flood_detector *.o *~ +install: + cp dns_flood_detector /usr/local/sbin/ + +dns_flood_detector: dns_flood_detector.c diff --git a/makefiles/Makefile-FreeBSD b/makefiles/Makefile-FreeBSD new file mode 100644 index 0000000..c21e536 --- /dev/null +++ b/makefiles/Makefile-FreeBSD @@ -0,0 +1,11 @@ +CFLAGS+=-O -g +LDLIBS=-lpcap -pthread -lm + +all: dns_flood_detector + strip dns_flood_detector +clean: + rm -rf dns_flood_detector *.o *~ +install: + cp dns_flood_detector /usr/local/sbin/ + +dns_flood_detector: dns_flood_detector.c diff --git a/makefiles/Makefile-Linux b/makefiles/Makefile-Linux new file mode 100644 index 0000000..d4b3300 --- /dev/null +++ b/makefiles/Makefile-Linux @@ -0,0 +1,11 @@ +CFLAGS=-O -D_BSD_SOURCE -g +LDLIBS=-lpcap -lpthread -lm + +all: dns_flood_detector + strip dns_flood_detector +clean: + rm -rf dns_flood_detector *.o *~ +install: + cp dns_flood_detector /usr/local/sbin/ + +dns_flood_detector: dns_flood_detector.c diff --git a/makefiles/Makefile-OSX b/makefiles/Makefile-OSX new file mode 100644 index 0000000..009e06f --- /dev/null +++ b/makefiles/Makefile-OSX @@ -0,0 +1,11 @@ +CFLAGS+=-O -g -I/usr/local/include -I/usr/include +LDLIBS=-L/usr/local/lib -lpcap -lpthread -lm + +all: dns_flood_detector + strip dns_flood_detector +clean: + rm -rf dns_flood_detector *.o *~ +install: + cp dns_flood_detector /usr/local/sbin/ + +dns_flood_detector: dns_flood_detector.c diff --git a/makefiles/Makefile-Solaris b/makefiles/Makefile-Solaris new file mode 100644 index 0000000..9c8c9ec --- /dev/null +++ b/makefiles/Makefile-Solaris @@ -0,0 +1,11 @@ +CFLAGS+=-O -g -I/usr/local/include -I/usr/include +LDLIBS=-L/usr/local/lib -L/usr/lib -lpcap -lpthread -lm -lsocket -lnsl + +all: dns_flood_detector + strip dns_flood_detector +clean: + rm -rf dns_flood_detector *.o *~ +install: + cp dns_flood_detector /usr/local/sbin/ + +dns_flood_detector: dns_flood_detector.c