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NetBSD/dist/ipf/ip_irc_pxy.c

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/* $NetBSD: ip_irc_pxy.c,v 1.1.1.4 2005/02/19 21:26:02 martti Exp $ */
/*
* Copyright (C) 2000-2003 Darren Reed
*
* See the IPFILTER.LICENCE file for details on licencing.
*
* Id: ip_irc_pxy.c,v 2.39.2.4 2005/02/04 10:22:55 darrenr Exp
*/
#define IPF_IRC_PROXY
#define IPF_IRCBUFSZ 96 /* This *MUST* be >= 64! */
int ippr_irc_init __P((void));
void ippr_irc_fini __P((void));
int ippr_irc_new __P((fr_info_t *, ap_session_t *, nat_t *));
int ippr_irc_out __P((fr_info_t *, ap_session_t *, nat_t *));
int ippr_irc_send __P((fr_info_t *, nat_t *));
int ippr_irc_complete __P((ircinfo_t *, char *, size_t));
u_short ipf_irc_atoi __P((char **));
static frentry_t ircnatfr;
int irc_proxy_init = 0;
/*
* Initialize local structures.
*/
int ippr_irc_init()
{
bzero((char *)&ircnatfr, sizeof(ircnatfr));
ircnatfr.fr_ref = 1;
ircnatfr.fr_flags = FR_INQUE|FR_PASS|FR_QUICK|FR_KEEPSTATE;
MUTEX_INIT(&ircnatfr.fr_lock, "IRC proxy rule lock");
irc_proxy_init = 1;
return 0;
}
void ippr_irc_fini()
{
if (irc_proxy_init == 1) {
MUTEX_DESTROY(&ircnatfr.fr_lock);
irc_proxy_init = 0;
}
}
char *ippr_irc_dcctypes[] = {
"CHAT ", /* CHAT chat ipnumber portnumber */
"SEND ", /* SEND filename ipnumber portnumber */
"MOVE ",
"TSEND ",
"SCHAT ",
NULL,
};
/*
* :A PRIVMSG B :^ADCC CHAT chat 0 0^A\r\n
* PRIVMSG B ^ADCC CHAT chat 0 0^A\r\n
*/
int ippr_irc_complete(ircp, buf, len)
ircinfo_t *ircp;
char *buf;
size_t len;
{
register char *s, c;
register size_t i;
u_32_t l;
int j, k;
ircp->irc_ipnum = 0;
ircp->irc_port = 0;
if (len < 31)
return 0;
s = buf;
c = *s++;
i = len - 1;
if ((c != ':') && (c != 'P'))
return 0;
if (c == ':') {
/*
* Loosely check that the source is a nickname of some sort
*/
s++;
c = *s;
ircp->irc_snick = s;
if (!ISALPHA(c))
return 0;
i--;
for (c = *s; !ISSPACE(c) && (i > 0); i--)
c = *s++;
if (i < 31)
return 0;
if (c != 'P')
return 0;
} else
ircp->irc_snick = NULL;
/*
* Check command string
*/
if (strncmp(s, "PRIVMSG ", 8))
return 0;
i -= 8;
s += 8;
c = *s;
ircp->irc_dnick = s;
/*
* Loosely check that the destination is a nickname of some sort
*/
if (!ISALPHA(c))
return 0;
for (; !ISSPACE(c) && (i > 0); i--)
c = *s++;
if (i < 20)
return 0;
s++,
i--;
/*
* Look for a ^A to start the DCC
*/
c = *s;
if (c == ':') {
s++;
c = *s;
}
if (strncmp(s, "\001DCC ", 4))
return 0;
i -= 4;
s += 4;
/*
* Check for a recognised DCC command
*/
for (j = 0, k = 0; ippr_irc_dcctypes[j]; j++) {
k = MIN(strlen(ippr_irc_dcctypes[j]), i);
if (!strncmp(ippr_irc_dcctypes[j], s, k))
break;
}
if (!ippr_irc_dcctypes[j])
return 0;
ircp->irc_type = s;
i -= k;
s += k;
if (i < 11)
return 0;
/*
* Check for the arg
*/
c = *s;
if (ISSPACE(c))
return 0;
ircp->irc_arg = s;
for (; (c != ' ') && (c != '\001') && (i > 0); i--)
c = *s++;
if (c == '\001') /* In reality a ^A can quote another ^A...*/
return 0;
if (i < 5)
return 0;
s++;
i--;
c = *s;
if (!ISDIGIT(c))
return 0;
ircp->irc_addr = s;
/*
* Get the IP#
*/
for (l = 0; ISDIGIT(c) && (i > 0); i--) {
l *= 10;
l += c - '0';
c = *s++;
}
if (i < 4)
return 0;
if (c != ' ')
return 0;
ircp->irc_ipnum = l;
s++;
i--;
c = *s;
if (!ISDIGIT(c))
return 0;
/*
* Get the port#
*/
for (l = 0; ISDIGIT(c) && (i > 0); i--) {
l *= 10;
l += c - '0';
c = *s++;
}
if (i < 3)
return 0;
if (strncmp(s, "\001\r\n", 3))
return 0;
s += 3;
ircp->irc_len = s - buf;
ircp->irc_port = l;
return 1;
}
int ippr_irc_new(fin, aps, nat)
fr_info_t *fin;
ap_session_t *aps;
nat_t *nat;
{
ircinfo_t *irc;
KMALLOC(irc, ircinfo_t *);
if (irc == NULL)
return -1;
fin = fin; /* LINT */
nat = nat; /* LINT */
aps->aps_data = irc;
aps->aps_psiz = sizeof(ircinfo_t);
bzero((char *)irc, sizeof(*irc));
return 0;
}
int ippr_irc_send(fin, nat)
fr_info_t *fin;
nat_t *nat;
{
char ctcpbuf[IPF_IRCBUFSZ], newbuf[IPF_IRCBUFSZ];
tcphdr_t *tcp, tcph, *tcp2 = &tcph;
int off, inc = 0, i, dlen;
size_t nlen = 0, olen;
struct in_addr swip;
u_short a5, sp;
ircinfo_t *irc;
fr_info_t fi;
nat_t *nat2;
u_int a1;
ip_t *ip;
mb_t *m;
#ifdef MENTAT
mb_t *m1;
#endif
m = fin->fin_m;
ip = fin->fin_ip;
tcp = (tcphdr_t *)fin->fin_dp;
bzero(ctcpbuf, sizeof(ctcpbuf));
off = (char *)tcp - (char *)ip + (TCP_OFF(tcp) << 2) + fin->fin_ipoff;
#ifdef __sgi
dlen = fin->fin_plen - off;
#else
dlen = MSGDSIZE(m) - off;
#endif
if (dlen <= 0)
return 0;
COPYDATA(m, off, MIN(sizeof(ctcpbuf), dlen), ctcpbuf);
if (dlen <= 0)
return 0;
ctcpbuf[sizeof(ctcpbuf) - 1] = '\0';
*newbuf = '\0';
irc = nat->nat_aps->aps_data;
if (ippr_irc_complete(irc, ctcpbuf, dlen) == 0)
return 0;
/*
* check that IP address in the PORT/PASV reply is the same as the
* sender of the command - prevents using PORT for port scanning.
*/
if (irc->irc_ipnum != ntohl(nat->nat_inip.s_addr))
return 0;
a5 = irc->irc_port;
/*
* Calculate new address parts for the DCC command
*/
a1 = ntohl(ip->ip_src.s_addr);
olen = irc->irc_len;
i = irc->irc_addr - ctcpbuf;
i++;
(void) strncpy(newbuf, ctcpbuf, i);
/* DO NOT change these! */
#if defined(SNPRINTF) && defined(KERNEL)
SNPRINTF(newbuf, sizeof(newbuf) - i, "%u %u\001\r\n", a1, a5);
#else
(void) sprintf(newbuf, "%u %u\001\r\n", a1, a5);
#endif
nlen = strlen(newbuf);
inc = nlen - olen;
if ((inc + ip->ip_len) > 65535)
return 0;
#ifdef MENTAT
for (m1 = m; m1->b_cont; m1 = m1->b_cont)
;
if ((inc > 0) && (m1->b_datap->db_lim - m1->b_wptr < inc)) {
mblk_t *nm;
/* alloc enough to keep same trailer space for lower driver */
nm = allocb(nlen, BPRI_MED);
PANIC((!nm),("ippr_irc_out: allocb failed"));
nm->b_band = m1->b_band;
nm->b_wptr += nlen;
m1->b_wptr -= olen;
PANIC((m1->b_wptr < m1->b_rptr),
("ippr_irc_out: cannot handle fragmented data block"));
linkb(m1, nm);
} else {
# if SOLARIS && defined(ICK_VALID)
if (m1->b_datap->db_struiolim == m1->b_wptr)
m1->b_datap->db_struiolim += inc;
m1->b_datap->db_struioflag &= ~STRUIO_IP;
# endif
m1->b_wptr += inc;
}
#else
if (inc < 0)
m_adj(m, inc);
/* the mbuf chain will be extended if necessary by m_copyback() */
#endif
COPYBACK(m, off, nlen, newbuf);
if (inc != 0) {
#if defined(MENTAT) || defined(__sgi)
register u_32_t sum1, sum2;
sum1 = ip->ip_len;
sum2 = ip->ip_len + inc;
/* Because ~1 == -2, We really need ~1 == -1 */
if (sum1 > sum2)
sum2--;
sum2 -= sum1;
sum2 = (sum2 & 0xffff) + (sum2 >> 16);
fix_outcksum(fin, &ip->ip_sum, sum2);
#endif
ip->ip_len += inc;
}
/*
* Add skeleton NAT entry for connection which will come back the
* other way.
*/
sp = htons(a5);
/*
* Don't allow the PORT command to specify a port < 1024 due to
* security crap.
*/
if (ntohs(sp) < 1024)
return 0;
/*
* The server may not make the connection back from port 20, but
* it is the most likely so use it here to check for a conflicting
* mapping.
*/
bcopy((caddr_t)fin, (caddr_t)&fi, sizeof(fi));
fi.fin_data[0] = sp;
fi.fin_data[1] = fin->fin_data[1];
nat2 = nat_outlookup(fin, IPN_TCP, nat->nat_p, nat->nat_inip,
ip->ip_dst);
if (nat2 == NULL) {
bcopy((caddr_t)fin, (caddr_t)&fi, sizeof(fi));
bzero((char *)tcp2, sizeof(*tcp2));
tcp2->th_win = htons(8192);
tcp2->th_sport = sp;
tcp2->th_dport = 0; /* XXX - don't specify remote port */
fi.fin_state = NULL;
fi.fin_nat = NULL;
fi.fin_data[0] = ntohs(sp);
fi.fin_data[1] = 0;
fi.fin_dp = (char *)tcp2;
fi.fin_fr = &ircnatfr;
fi.fin_dlen = sizeof(*tcp2);
fi.fin_plen = fi.fin_hlen + sizeof(*tcp2);
swip = ip->ip_src;
ip->ip_src = nat->nat_inip;
nat2 = nat_new(&fi, nat->nat_ptr, NULL,
NAT_SLAVE|IPN_TCP|SI_W_DPORT, NAT_OUTBOUND);
if (nat2 != NULL) {
(void) nat_proto(&fi, nat2, 0);
nat_update(&fi, nat2, nat2->nat_ptr);
(void) fr_addstate(&fi, NULL, SI_W_DPORT);
if (fi.fin_state != NULL)
fr_statederef(&fi, (ipstate_t **)&fi.fin_state);
}
ip->ip_src = swip;
}
return inc;
}
int ippr_irc_out(fin, aps, nat)
fr_info_t *fin;
ap_session_t *aps;
nat_t *nat;
{
aps = aps; /* LINT */
return ippr_irc_send(fin, nat);
}
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