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HardenedBSD/sbin/ipfw/ipfw.c
Ugen J.S. Antsilevich 98bee36695 Utility changes following the facility. 
We have only one firewall chain and one accounting chain now.
   No blocking/forwarding so commands changed.
Man pages are somewhat out of date and will be updated ASAP.
1995-01-12 13:01:21 +00:00

1030 lines
18 KiB
C
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/*
* Copyright (c) 1994 Ugen J.S.Antsilevich
* Idea and grammar partially left from:
* Copyright (c) 1993 Daniel Boulet
*
* Redistribution and use in source forms, with and without modification,
* are permitted provided that this entire comment appears intact.
*
* Redistribution in binary form may occur without any restrictions.
* Obviously, it would be nice if you gave credit where credit is due
* but requiring it would be too onerous.
*
* This software is provided ``AS IS'' without any warranties of any kind.
*
* NEW command line interface for IP firewall facility
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <fcntl.h>
#include <limits.h>
#include <netdb.h>
#include <kvm.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#include <netinet/tcp.h>
#define IPFIREWALL
#define IPACCT
#include <netinet/ip_fw.h>
#define MAXSTR 25
char progname[MAXSTR]; /* Program name for errors */
char proto_name[MAXSTR]=""; /* Current line protocol */
int s; /* main RAW socket */
int do_resolv=1; /* Would try to resolv all */
int do_short=0; /* Compact output */
int do_acct=0; /* Show packet/byte count */
int ports_ok=0; /* flag allowing ports */
u_short flags=0; /* New entry flags */
#define FW 1 /* Firewall action */
#define AC 2 /* Accounting action */
#define S_SEP1 "f" /* of "from" */
#define S_SEP2 "t" /* of "to" */
#define S_SEP3 "v" /* of "via" */
#define P_AC "a" /* of "accept" for policy action */
#define P_DE "d" /* of "deny" for policy action */
#define CH_FW "f" /* of "firewall" for chains in zero/flush */
#define CH_AC "a" /* of "accounting" for chain in zero/flush/list */
char action_tab[][MAXSTR]={
"addf",
#define A_ADDF 0
"delf",
#define A_DELF 1
"chkf",
#define A_CHKF 2
"adda",
#define A_ADDA 3
"dela",
#define A_DELA 4
"clr",
#define A_CLRA 5
"f",
#define A_FLUSH 6
"z",
#define A_ZERO 7
"l",
#define A_LIST 8
"p",
#define A_POLICY 9
"",
#define A_NONE 10
};
char type_tab[][MAXSTR]={
"ac",
#define T_ACCEPT 0
"lo",
#define T_LOG 1
"r",
#define T_REJECT 2
"lr",
#define T_LREJECT 3
"d",
#define T_DENY 4
"ld",
#define T_LDENY 5
"si",
#define T_SINGLE 6
"bi",
#define T_BIDIR 7
"",
#define T_NONE 8
};
char proto_tab[][MAXSTR]={
"all",
#define P_ALL 0
"icmp",
#define P_ICMP 1
"tcp",
#define P_TCP 2
"syn",
#define P_SYN 3
"udp",
#define P_UDP 4
""
#define P_NONE 5
};
struct nlist nlf[]={
#define N_FCHAIN 0
{ "_ip_fw_chain" },
#define N_POLICY 1
{ "_ip_fw_policy" },
"" ,
};
struct nlist nla[]={
#define N_ACHAIN 0
{ "_ip_acct_chain" },
"" ,
};
int mask_bits(m_ad)
struct in_addr m_ad;
{
int h_fnd=0,h_num=0,i;
u_long mask;
mask=ntohl(m_ad.s_addr);
for (i=0;i<sizeof(u_long)*CHAR_BIT;i++) {
if (mask & 1L) {
h_fnd=1;
h_num++;
} else {
if (h_fnd)
return -1;
}
mask=mask>>1;
}
return h_num;
}
void
show_ipfw(chain,c_t)
struct ip_fw *chain;
int c_t;
{
char *comma;
u_long adrt;
struct hostent *he;
int i,mb;
if (do_short && do_acct) {
printf("%8d:%8d ",chain->fw_bcnt,chain->fw_pcnt);
}
if (do_short)
if (c_t==FW) {
if (chain->fw_flg & IP_FW_F_ACCEPT)
if (chain->fw_flg & IP_FW_F_PRN)
printf("l");
else
printf("a");
else
if (chain->fw_flg & IP_FW_F_PRN)
if (chain->fw_flg & IP_FW_F_ICMPRPL)
printf("R");
else
printf("D");
else
if (chain->fw_flg & IP_FW_F_ICMPRPL)
printf("r");
else
printf("d");
} else {
if (chain->fw_flg & IP_FW_F_BIDIR)
printf("b");
else
printf("s");
}
else
if (c_t==FW) {
if (chain->fw_flg & IP_FW_F_ACCEPT)
if (chain->fw_flg & IP_FW_F_PRN)
printf("log ");
else
printf("accept ");
else
if (chain->fw_flg & IP_FW_F_PRN)
if (chain->fw_flg & IP_FW_F_ICMPRPL)
printf("lreject ");
else
printf("ldeny ");
else
if (chain->fw_flg & IP_FW_F_ICMPRPL)
printf("reject ");
else
printf("deny ");
} else {
if (chain->fw_flg & IP_FW_F_BIDIR)
printf("bidir ");
else
printf("single ");
}
if (do_short)
switch (chain->fw_flg & IP_FW_F_KIND) {
case IP_FW_F_ICMP:
printf("I ");
break;
case IP_FW_F_TCP:
if (chain->fw_flg&IP_FW_F_TCPSYN)
printf("S ");
else
printf("T ");
break;
case IP_FW_F_UDP:
printf("U ");
break;
case IP_FW_F_ALL:
printf("A ");
break;
default:
break;
}
else
switch (chain->fw_flg & IP_FW_F_KIND) {
case IP_FW_F_ICMP:
printf("icmp ");
break;
case IP_FW_F_TCP:
if (chain->fw_flg&IP_FW_F_TCPSYN)
printf("syn ");
else
printf("tcp ");
break;
case IP_FW_F_UDP:
printf("udp ");
break;
case IP_FW_F_ALL:
printf("all ");
break;
default:
break;
}
if (do_short)
printf("[");
else
printf("from ");
adrt=ntohl(chain->fw_smsk.s_addr);
if (adrt==ULONG_MAX && do_resolv) {
adrt=(chain->fw_src.s_addr);
he=gethostbyaddr((char *)&adrt,sizeof(u_long),AF_INET);
if (he==NULL) {
printf(inet_ntoa(chain->fw_src));
printf(":");
printf(inet_ntoa(chain->fw_smsk));
} else
printf("%s",he->h_name);
} else {
printf(inet_ntoa(chain->fw_src));
if (adrt!=ULONG_MAX)
if ((mb=mask_bits(chain->fw_smsk))>=0)
printf("/%d",mb);
else {
printf(":");
printf(inet_ntoa(chain->fw_smsk));
}
}
comma = " ";
for (i=0;i<chain->fw_nsp; i++ ) {
printf("%s%d",comma,chain->fw_pts[i]);
if (i==0 && (chain->fw_flg & IP_FW_F_SRNG))
comma = ":";
else
comma = ",";
}
if (do_short)
printf("][");
else
printf(" to ");
adrt=ntohl(chain->fw_dmsk.s_addr);
if (adrt==ULONG_MAX && do_resolv) {
adrt=(chain->fw_dst.s_addr);
he=gethostbyaddr((char *)&adrt,sizeof(u_long),AF_INET);
if (he==NULL) {
printf(inet_ntoa(chain->fw_dst));
printf(":");
printf(inet_ntoa(chain->fw_dmsk));
} else
printf("%s",he->h_name);
} else {
printf(inet_ntoa(chain->fw_dst));
if (adrt!=ULONG_MAX)
if ((mb=mask_bits(chain->fw_dmsk))>=0)
printf("/%d",mb);
else {
printf(":");
printf(inet_ntoa(chain->fw_dmsk));
}
}
comma = " ";
for (i=0;i<chain->fw_ndp;i++) {
printf("%s%d",comma,chain->fw_pts[chain->fw_nsp+i]);
if (i==chain->fw_nsp && (chain->fw_flg & IP_FW_F_DRNG))
comma = ":";
else
comma = ",";
}
if (chain->fw_via.s_addr) {
if (do_short)
printf("][");
else
printf(" via ");
printf(inet_ntoa(chain->fw_via));
}
if (do_short)
printf("]\n");
else
printf("\n");
}
list(av)
char **av;
{
kvm_t *kd;
static char errb[_POSIX2_LINE_MAX];
struct ip_fw b,*btmp;
if (!(kd=kvm_openfiles(NULL,NULL,NULL,O_RDONLY,errb))) {
fprintf(stderr,"%s: kvm_openfiles: %s\n",
progname,kvm_geterr(kd));
exit(1);
}
if (*av==NULL || !strncmp(*av,CH_FW,strlen(CH_FW))) {
if (kvm_nlist(kd,nlf)<0 || nlf[0].n_type==0) {
fprintf(stderr,"%s: kvm_nlist: no namelist in %s\n",
progname,getbootfile());
exit(1);
}
}
if (*av==NULL || !strncmp(*av,CH_FW,strlen(CH_FW))) {
kvm_read(kd,(u_long)nlf[N_FCHAIN].n_value,&b,sizeof(struct ip_fw));
printf("FireWall chain entries:\n");
while(b.fw_next!=NULL) {
btmp=b.fw_next;
kvm_read(kd,(u_long)btmp,&b,sizeof(struct ip_fw));
show_ipfw(&b,FW);
}
}
if (*av==NULL || !strncmp(*av,CH_AC,strlen(CH_AC))) {
if (kvm_nlist(kd,nla)<0 || nla[0].n_type==0) {
fprintf(stderr,"%s: kvm_nlist: no namelist in %s\n",
progname,getbootfile());
exit(1);
}
}
if (*av==NULL || !strncmp(*av,CH_AC,strlen(CH_AC))) {
kvm_read(kd,(u_long)nla[N_ACHAIN].n_value,&b,sizeof(struct ip_fw));
printf("Accounting chain entries:\n");
while(b.fw_next!=NULL) {
btmp=b.fw_next;
kvm_read(kd,(u_long)btmp,&b,sizeof(struct ip_fw));
show_ipfw(&b,AC);
}
}
}
int get_num(str,tab)
char *str;
char tab[][MAXSTR];
{
int i=0;
while(tab[i][0]!='\0') {
if (strlen(str)>=strlen(tab[i]))
if (!strncmp(str,tab[i],strlen(tab[i])))
return i;
i++;
}
return i;
}
void show_usage()
{
printf("%s: bad arguments\n",progname);
}
u_short get_port(str)
char *str;
{
struct servent *sptr;
char *end;
int port,slen = strlen(str);
if ((slen>0) && (strspn(str,"0123456789")==slen)) {
port = strtol(str,&end,10);
if (*end!='\0') {
fprintf(stderr,"%s: illegal port number :%s\n"
,progname,str);
exit(1);
}
if ((port<=0) || (port>USHRT_MAX)) {
fprintf(stderr,"%s: port number out of range :%d\n"
,progname,port);
exit(1);
}
return((u_short)port);
} else {
sptr = getservbyname(str,proto_name);
if (!sptr) {
fprintf(stderr,"%s: unknown service :%s\n"
,progname,str);
exit(1);
}
return((u_short)ntohs(sptr->s_port));
}
}
char *findchar(str,c)
char *str;
char c;
{
int i,len=strlen(str);
for (i=0;i<len;i++) {
if (str[i]==c)
return(char*)(&str[i]);
}
return NULL;
}
int set_entry_ports(str,ports,a_max,is_range)
char *str;
u_short *ports;
int a_max;
int *is_range;
{
char *s_pr2,*s_h,*s_t,*cp;
u_short p1,p2;
int i=0;
(void)strtok(str,":");
s_pr2=strtok(NULL,"");
if (s_pr2) {
p1 = get_port(str);
p2 = get_port(s_pr2);
if (a_max<2) {
fprintf(stderr,"%s: too many ports.\n",progname);
exit(1);
}
ports[0]=p1;
ports[1]=p2;
*is_range=1;
return 2;
}
s_h=str;
while ((cp=findchar(s_h,','))!=NULL) {
if (i>a_max) {
fprintf(stderr,"%s: too many ports.\n",progname);
exit(1);
}
*cp='\0';
if ((s_t=(++cp))=='\0') {
fprintf(stderr,"%s: bad port list.\n",progname);
exit(1);
}
ports[i++]=get_port(s_h);
s_h=s_t;
}
if (i>a_max) {
fprintf(stderr,"%s: too many ports.\n",progname);
exit(1);
}
ports[i]=get_port(s_h);
*is_range=0;
return (i+1);
}
void set_entry_ip(str,addr,mask)
char *str;
struct in_addr *addr,*mask;
{
char *sm_bit,*sm_oct,*end;
int n_bit;
struct hostent *hptr;
if (mask) {
(void)strtok(str,"/");
sm_bit=strtok(NULL,"");
(void)strtok(str,":");
sm_oct=strtok(NULL,"");
}
if (!inet_aton(str,addr)) {
if (do_resolv) {
if (!(hptr=gethostbyname(str))) {
fprintf(stderr,"%s: Unknown host name : %s\n",
progname,str);
exit(1);
} else {
addr->s_addr=*((u_long *)hptr->h_addr);
}
} else {
fprintf(stderr,"%s: Bad IP : %s\n",progname,str);
exit(1);
}
}
/*
* This is in case mask we
* want to set IP only
*/
if (!mask)
return;
mask->s_addr=htonl(ULONG_MAX);
if (sm_bit) {
n_bit = strtol(sm_bit,&end,10);
if (*end!='\0') {
show_usage();
exit(1);
}
if (n_bit<0 || n_bit>sizeof(u_long)*CHAR_BIT) {
show_usage();
exit(1);
}
if (n_bit>0)
mask->s_addr=
htonl(ULONG_MAX<<(sizeof(u_long)*CHAR_BIT-n_bit));
else
mask->s_addr=0L;
}
if (sm_oct) {
if (!inet_aton(sm_oct,mask)) {
show_usage();
exit(1);
}
}
/*
* Ugh..better of corse do it in kernel so no error possible
* but faster here so this way it goes...
*/
addr->s_addr=mask->s_addr & addr->s_addr;
}
void set_entry(av,frwl)
char **av;
struct ip_fw * frwl;
{
int p_num=0,ir=0;
frwl->fw_nsp=0;
frwl->fw_ndp=0;
frwl->fw_via.s_addr=0L;
if (strncmp(*av,S_SEP1,strlen(S_SEP1))) {
show_usage();
exit(1);
}
if (*(++av)==NULL) {
show_usage();
exit(1);
}
set_entry_ip(*av,&(frwl->fw_src),&(frwl->fw_smsk));
if (*(++av)==NULL) {
show_usage();
exit(1);
}
if (!strncmp(*av,S_SEP2,strlen(S_SEP2)))
goto no_src_ports;
if (ports_ok) {
frwl->fw_nsp=
set_entry_ports(*av,frwl->fw_pts,IP_FW_MAX_PORTS,&ir);
if (ir)
flags|=IP_FW_F_SRNG;
if (*(++av)==NULL) {
show_usage();
exit(1);
}
}
no_src_ports:
if (strncmp(*av,S_SEP2,strlen(S_SEP2))) {
show_usage();
exit(1);
}
if (*(++av)==NULL) {
show_usage();
exit(1);
}
set_entry_ip(*av,&(frwl->fw_dst),&(frwl->fw_dmsk));
if (*(++av)==NULL)
goto no_tail;
if (!strncmp(*av,S_SEP3,strlen(S_SEP3)))
goto no_dst_ports;
if (ports_ok) {
frwl->fw_ndp=
set_entry_ports(*av,&(frwl->fw_pts[frwl->fw_nsp]),
(IP_FW_MAX_PORTS-frwl->fw_nsp),&ir);
if (ir)
flags|=IP_FW_F_DRNG;
}
no_dst_ports:
if (strncmp(*av,S_SEP3,strlen(S_SEP3))) {
show_usage();
exit(1);
}
if (*(++av)==NULL) {
show_usage();
exit(1);
}
set_entry_ip(*av,&(frwl->fw_via),NULL);
no_tail:
}
flush(av)
char **av;
{
if (*av==NULL) {
if (setsockopt(s,IPPROTO_IP,IP_FW_FLUSH,NULL,0)<0) {
fprintf(stderr,"%s: setsockopt failed.\n",progname);
exit(1);
} else {
printf("All firewall entries flushed.\n");
}
if (setsockopt(s,IPPROTO_IP,IP_ACCT_FLUSH,NULL,0)<0) {
fprintf(stderr,"%s: setsockopt failed.\n",progname);
exit(1);
} else {
printf("All accounting entries flushed.\n");
}
exit(0);
}
if (!strncmp(*av,CH_FW,strlen(CH_FW))) {
if (setsockopt(s,IPPROTO_IP,IP_FW_FLUSH,NULL,0)<0) {
fprintf(stderr,"%s: setsockopt failed.\n",progname);
exit(1);
} else {
printf("All firewall entries flushed.\n");
exit(0);
}
}
if (!strncmp(*av,CH_AC,strlen(CH_AC))) {
if (setsockopt(s,IPPROTO_IP,IP_ACCT_FLUSH,NULL,0)<0) {
fprintf(stderr,"%s: setsockopt failed.\n",progname);
exit(1);
} else {
printf("All accounting entries flushed.\n");
exit(0);
}
}
}
void policy(av)
char **av;
{
u_short p=0,b;
kvm_t *kd;
static char errb[_POSIX2_LINE_MAX];
if (*av==NULL || strlen(*av)<=0) {
if ( (kd=kvm_openfiles(NULL,NULL,NULL,O_RDONLY,errb)) == NULL) {
fprintf(stderr,"%s: kvm_openfiles: %s\n",progname,kvm_geterr(kd));
exit(1);
}
if (kvm_nlist(kd,nlf) < 0 || nlf[0].n_type == 0) {
fprintf(stderr,"%s: kvm_nlist: no namelist in %s\n",
progname,getbootfile());
exit(1);
}
kvm_read(kd,(u_long)nlf[N_POLICY].n_value,&b,sizeof(int));
if (b&IP_FW_P_DENY)
printf("Default policy: DENY\n");
else
printf("Default policy: ACCEPT\n");
exit(1);
}
if (!strncmp(*av,P_DE,strlen(P_DE)))
p|=IP_FW_P_DENY;
else
if (!strncmp(*av,P_AC,strlen(P_AC)))
p&=~IP_FW_P_DENY;
else {
fprintf(stderr,"%s: bad policy value.\n",progname);
exit(1);
}
if (setsockopt(s,IPPROTO_IP,IP_FW_POLICY,&p,sizeof(p))<0) {
fprintf(stderr,"%s: setsockopt failed.\n",progname);
exit(1);
} else {
if (p&IP_FW_P_DENY)
printf("Policy set to DENY.\n");
else
printf("Policy set to ACCEPT.\n");
exit(0);
}
}
zero()
{
if (setsockopt(s,IPPROTO_IP,IP_ACCT_ZERO,NULL,0)<0) {
fprintf(stderr,"%s: setsockopt failed.\n",progname);
exit(1);
} else {
printf("Accounting cleared.\n");
exit(0);
}
}
main(ac,av)
int ac;
char **av;
{
char ch;
extern int optind;
int ctl,int_t,is_check=0;
struct ip_fw frwl;
strcpy(progname,*av);
s = socket( AF_INET, SOCK_RAW, IPPROTO_RAW );
if ( s < 0 ) {
fprintf(stderr,"%s: Can't open raw socket.Must be root to use this programm. \n",progname);
exit(1);
}
if ( ac == 1 ) {
show_usage();
exit(1);
}
while ((ch = getopt(ac, av ,"ans")) != EOF)
switch(ch) {
case 'a':
do_acct=1;
break;
case 'n':
do_resolv=0;
break;
case 's':
do_short=1;
break;
case '?':
default:
show_usage();
exit(1);
}
if (*(av+=optind)==NULL) {
show_usage();
exit(1);
}
switch(get_num(*av,action_tab)) {
case A_ADDF:
ctl=IP_FW_ADD;
int_t=FW;
break;
case A_DELF:
ctl=IP_FW_DEL;
int_t=FW;
break;
case A_CHKF:
int_t=FW;
is_check=1;
break;
case A_ADDA:
ctl=IP_ACCT_ADD;
int_t=AC;
break;
case A_DELA:
ctl=IP_ACCT_DEL;
int_t=AC;
break;
case A_CLRA:
ctl=IP_ACCT_CLR;
int_t=AC;
break;
case A_FLUSH:
flush(++av);
exit(0); /* successful exit */
case A_LIST:
list(++av);
exit(0); /* successful exit */
case A_ZERO:
zero();
exit(0); /* successful exit */
case A_POLICY:
policy(++av);
exit(0); /* we never get here */
default:
show_usage();
exit(1);
} /* main action switch */
if (is_check)
goto proto_switch;
if (*(++av)==NULL) {
show_usage();
exit(1);
}
switch(get_num(*av,type_tab)) {
case T_LREJECT:
flags|=IP_FW_F_PRN;
case T_REJECT:
flags|=IP_FW_F_ICMPRPL;
if (int_t!=FW) {
show_usage();
exit(1);
}
break;
case T_LDENY:
flags|=IP_FW_F_PRN;
case T_DENY:
flags|=0; /* just to show it related to flags */
if (int_t!=FW) {
show_usage();
exit(1);
}
break;
case T_LOG:
flags|=IP_FW_F_PRN;
case T_ACCEPT:
flags|=IP_FW_F_ACCEPT;
if (int_t!=FW) {
show_usage();
exit(1);
}
break;
case T_SINGLE:
flags|=0; /* just to show it related to flags */
if (int_t!=AC) {
show_usage();
exit(1);
}
break;
case T_BIDIR:
flags|=IP_FW_F_BIDIR;
if (int_t!=AC) {
show_usage();
exit(1);
}
break;
default:
show_usage();
exit(1);
} /* type of switch */
proto_switch:
if (*(++av)==NULL) {
show_usage();
exit(1);
}
switch(get_num(*av,proto_tab)) {
case P_ALL:
flags|=IP_FW_F_ALL;
break;
case P_ICMP:
flags|=IP_FW_F_ICMP;
break;
case P_SYN:
flags|=IP_FW_F_TCPSYN;
case P_TCP:
flags|=IP_FW_F_TCP;
ports_ok=1;
strcpy(proto_name,"tcp");
break;
case P_UDP:
flags|=IP_FW_F_UDP;
ports_ok=1;
strcpy(proto_name,"udp");
break;
default:
show_usage();
exit(1);
}
if (*(++av)==NULL) {
show_usage();
exit(1);
}
set_entry(av,&frwl);
frwl.fw_flg=flags;
if (is_check) {
#ifndef disabled
fprintf(stderr,"%s: checking disabled.\n",progname);
#else
struct ip *pkt;
struct tcphdr *th;
int p_len=sizeof(struct ip)+sizeof(struct tcphdr);
pkt=(struct ip*)malloc(p_len);
pkt->ip_v = IPVERSION;
pkt->ip_hl = sizeof(struct ip)/sizeof(int);
th=(struct tcphdr *)(pkt+1);
switch(get_num(proto_name,proto_tab)) {
case P_TCP:
pkt->ip_p = IPPROTO_TCP;
break;
case P_UDP:
pkt->ip_p = IPPROTO_UDP;
break;
default:
fprintf(stderr,"%s: can check TCP/UDP packets\
only.\n",progname);
exit(1);
}
if (frwl.fw_nsp!=1 || frwl.fw_ndp!=1) {
fprintf(stderr,"%s: check needs one src/dst port.\n",
progname);
exit(1);
}
if (ntohl(frwl.fw_smsk.s_addr)!=ULONG_MAX ||
ntohl(frwl.fw_dmsk.s_addr)!=ULONG_MAX) {
fprintf(stderr,"%s: can't check masked IP.\n",progname);
exit(1);
}
pkt->ip_src.s_addr=frwl.fw_src.s_addr;
pkt->ip_dst.s_addr=frwl.fw_dst.s_addr;
th->th_sport=htons(frwl.fw_pts[0]);
th->th_dport=htons(frwl.fw_pts[frwl.fw_nsp]);
if (setsockopt(s,IPPROTO_IP,ctl,pkt,p_len))
printf("Packet DENYED.\n");
else
printf("Packet ACCEPTED.\n");
exit(0);
#endif
} else {
if (setsockopt(s,IPPROTO_IP,ctl,&frwl,sizeof(frwl))<0) {
fprintf(stderr,"%s: setsockopt failed.\n",progname);
exit(1);
}
}
close(s);
}
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