Well..finally..this is the first part..it should take care of

matching IP options..Check and test this - i made only a couple
of rough tests and this could be buggy.. Ipaccounting can't use
IP Options (and i don't see any need to cound packets with specific
options either..)
More to come...
This commit is contained in:
Ugen J.S. Antsilevich 1995-10-01 21:52:50 +00:00
parent 1661971e0f
commit 37afa1e829
Notes: svn2git 2020-12-20 02:59:44 +00:00
svn path=/head/; revision=11119
2 changed files with 114 additions and 19 deletions

View File

@ -11,7 +11,7 @@
*
* This software is provided ``AS IS'' without any warranties of any kind.
*
* $Id: ip_fw.c,v 1.21 1995/07/23 05:36:29 davidg Exp $
* $Id: ip_fw.c,v 1.22 1995/07/31 13:58:35 gpalmer Exp $
*/
/*
@ -100,6 +100,77 @@ port_match(portptr, nports, port, range_flag)
}
int
ipopts_match(ip, f)
struct ip *ip;
struct ip_fw *f;
{
register u_char *cp;
int opt, optlen, cnt;
u_char opts, nopts, nopts_sve;
printf("Here\n");
cp = (u_char *)(ip + 1);
cnt = (ip->ip_hl << 2) - sizeof (struct ip);
opts = f->fw_ipopt;
nopts = nopts_sve = f->fw_ipnopt;
printf("opts = %x, nopts = %x\n", opts, nopts);
printf("Cnt = %d\n", cnt);
for (; cnt > 0; cnt -= optlen, cp += optlen) {
opt = cp[IPOPT_OPTVAL];
if (opt == IPOPT_EOL)
break;
if (opt == IPOPT_NOP)
optlen = 1;
else {
optlen = cp[IPOPT_OLEN];
if (optlen <= 0 || optlen > cnt) {
goto bad;
}
}
switch (opt) {
default:
break;
case IPOPT_LSRR:
printf("Has LSRR\n");
opts &= ~IP_FW_IPOPT_LSRR;
nopts &= ~IP_FW_IPOPT_LSRR;
break;
case IPOPT_SSRR:
opts &= ~IP_FW_IPOPT_SSRR;
nopts &= ~IP_FW_IPOPT_SSRR;
break;
case IPOPT_RR:
opts &= ~IP_FW_IPOPT_RR;
nopts &= ~IP_FW_IPOPT_RR;
break;
case IPOPT_TS:
opts &= ~IP_FW_IPOPT_TS;
nopts &= ~IP_FW_IPOPT_TS;
break;
}
if (opts == nopts)
break;
}
printf("opts = %x, nopts = %x\n", opts, nopts);
if (opts == 0 && nopts == nopts_sve)
return 1;
else
return 0;
bad:
if (ip_fw_policy & IP_FW_P_MBIPO)
return 1;
else
return 0;
}
/*
* Returns TRUE if it should be accepted, FALSE otherwise.
*/
@ -120,7 +191,6 @@ ip_fw_chk(m, ip, rif, chain)
struct in_addr src, dst, ia_i;
u_short src_port = 0, dst_port = 0;
u_short f_prt = 0, prt;
char notcpsyn = 1;
/*
* If the chain is empty allow any packet-this is equal to disabling
@ -153,8 +223,6 @@ ip_fw_chk(m, ip, rif, chain)
dprintf1("TCP ");
src_port = ntohs(tcp->th_sport);
dst_port = ntohs(tcp->th_dport);
if ((tcp->th_flags & TH_SYN) && !(tcp->th_flags & TH_ACK))
notcpsyn = 0; /* We *DO* have SYN ,value FALSE */
prt = IP_FW_F_TCP;
break;
case IPPROTO_UDP:
@ -174,11 +242,12 @@ ip_fw_chk(m, ip, rif, chain)
}
dprint_ip(ip->ip_src);
if (ip->ip_p == IPPROTO_TCP || ip->ip_p == IPPROTO_UDP) {
dprintf2(":%d ", src_port);
}
dprintf2(":%d", src_port);
}
dprintf1(" ");
dprint_ip(ip->ip_dst);
if (ip->ip_p == IPPROTO_TCP || ip->ip_p == IPPROTO_UDP) {
dprintf2(":%d ", dst_port);
dprintf2(":%d", dst_port);
}
dprintf1("\n");
@ -225,20 +294,22 @@ ip_fw_chk(m, ip, rif, chain)
*/
continue;
via_match:
/*
* If we get matching IP options, we may continue
* checking ,else we have nothing to do here.
* We DO check options only if some are set in
* the entry definition. If both set and unset
* options equal - nothing to check.
*/
if (f->fw_ipopt != f->fw_ipnopt)
if (!ipopts_match(ip, f))
continue;
f_prt = f->fw_flg & IP_FW_F_KIND;
if (f_prt == IP_FW_F_ALL) {
/* Universal frwl - we've got a match! */
goto got_match;
} else {
/*
* This is actually buggy as if you set SYN
* flag on UDp or ICMP firewall it will never
* work,but actually it is a concern of
* software which sets firewall entries.
*/
if (f->fw_flg & IP_FW_F_TCPSYN && notcpsyn)
continue;
/*
* Specific firewall - packet's protocol must
* match firewall's
@ -650,6 +721,10 @@ add_entry(chainptr, frwl)
skip_check:
}
if (ftmp->fw_ipopt != 0 && chtmp->fw_ipopt == 0)
addb4++;
if (ftmp->fw_ipnopt != 0 && chtmp->fw_ipnopt == 0)
addb4++;
}
if (addb4 > 0) {
if (chtmp_prev != NULL) {

View File

@ -11,7 +11,7 @@
*
* This software is provided ``AS IS'' without any warranties of any kind.
*
* $Id$
* $Id: ip_fw.h,v 1.13 1995/07/23 05:36:30 davidg Exp $
*/
/*
@ -49,6 +49,8 @@ struct ip_fw {
#define IP_FW_MAX_PORTS 10 /* A reasonable maximum */
u_short fw_pts[IP_FW_MAX_PORTS]; /* Array of port numbers to match */
u_long fw_pcnt,fw_bcnt; /* Packet and byte counters */
u_char fw_ipopt,fw_ipnopt; /* IP options set/unset */
u_char fw_tcpf,fw_tcpnf; /* TCP flags sen/unset */
};
@ -83,11 +85,28 @@ struct ip_fw {
* */
#define IP_FW_F_PRN 0x020 /* In verbose mode print this firewall*/
#define IP_FW_F_BIDIR 0x040 /* For accounting-count two way */
#define IP_FW_F_TCPSYN 0x080 /* For tcp packets-check SYN only */
#define IP_FW_F_ICMPRPL 0x100 /* Send back icmp unreachable packet */
#define IP_FW_F_IFNAME 0x200 /* Use interface name/unit (not IP) */
#define IP_FW_F_MASK 0x3FF /* All possible flag bits mask */
/*
* Definitions for IP option names.
*/
#define IP_FW_IPOPT_LSRR 0x01
#define IP_FW_IPOPT_SSRR 0x02
#define IP_FW_IPOPT_RR 0x04
#define IP_FW_IPOPT_TS 0x08
/*
* Definitions for TCP flags.
*/
#define IP_FW_TCPF_FIN TH_FIN
#define IP_FW_TCPF_SYN TH_SYN
#define IP_FW_TCPF_RST TH_RST
#define IP_FW_TCPF_PUSH TH_PUSH
#define IP_FW_TCPF_ACK TH_ACK
#define IP_FW_TCPF_URG TH_URG
/*
* New IP firewall options for [gs]etsockopt at the RAW IP level.
*/
@ -109,7 +128,8 @@ struct ip_fw {
*/
#define IP_FW_P_DENY 0x01
#define IP_FW_P_ICMP 0x02
#define IP_FW_P_MASK 0x03
#define IP_FW_P_MBIPO 0x04
#define IP_FW_P_MASK 0x07
/*