428 lines
7.8 KiB
C
428 lines
7.8 KiB
C
/* $NetBSD: ip_irc_pxy.c,v 1.1.1.1 2004/03/28 08:56:44 martti Exp $ */
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/*
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* Copyright (C) 2000-2003 Darren Reed
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*
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* See the IPFILTER.LICENCE file for details on licencing.
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*
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* Id: ip_irc_pxy.c,v 2.39 2004/01/31 14:48:44 darrenr Exp
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*/
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#define IPF_IRC_PROXY
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#define IPF_IRCBUFSZ 96 /* This *MUST* be >= 64! */
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int ippr_irc_init __P((void));
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void ippr_irc_fini __P((void));
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int ippr_irc_new __P((fr_info_t *, ap_session_t *, nat_t *));
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int ippr_irc_out __P((fr_info_t *, ap_session_t *, nat_t *));
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int ippr_irc_send __P((fr_info_t *, nat_t *));
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int ippr_irc_complete __P((ircinfo_t *, char *, size_t));
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u_short ipf_irc_atoi __P((char **));
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static frentry_t ircnatfr;
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int irc_proxy_init = 0;
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/*
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* Initialize local structures.
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*/
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int ippr_irc_init()
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{
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bzero((char *)&ircnatfr, sizeof(ircnatfr));
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ircnatfr.fr_ref = 1;
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ircnatfr.fr_flags = FR_INQUE|FR_PASS|FR_QUICK|FR_KEEPSTATE;
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MUTEX_INIT(&ircnatfr.fr_lock, "IRC proxy rule lock");
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irc_proxy_init = 1;
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return 0;
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}
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void ippr_irc_fini()
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{
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if (irc_proxy_init == 1) {
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MUTEX_DESTROY(&ircnatfr.fr_lock);
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irc_proxy_init = 0;
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}
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}
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char *ippr_irc_dcctypes[] = {
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"CHAT ", /* CHAT chat ipnumber portnumber */
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"SEND ", /* SEND filename ipnumber portnumber */
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"MOVE ",
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"TSEND ",
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"SCHAT ",
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NULL,
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};
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/*
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* :A PRIVMSG B :^ADCC CHAT chat 0 0^A\r\n
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* PRIVMSG B ^ADCC CHAT chat 0 0^A\r\n
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*/
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int ippr_irc_complete(ircp, buf, len)
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ircinfo_t *ircp;
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char *buf;
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size_t len;
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{
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register char *s, c;
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register size_t i;
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u_32_t l;
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int j, k;
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ircp->irc_ipnum = 0;
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ircp->irc_port = 0;
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if (len < 31)
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return 0;
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s = buf;
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c = *s++;
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i = len - 1;
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if ((c != ':') && (c != 'P'))
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return 0;
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if (c == ':') {
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/*
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* Loosely check that the source is a nickname of some sort
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*/
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s++;
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c = *s;
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ircp->irc_snick = s;
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if (!isalpha(c))
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return 0;
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i--;
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for (c = *s; !isspace(c) && (i > 0); i--)
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c = *s++;
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if (i < 31)
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return 0;
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if (c != 'P')
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return 0;
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} else
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ircp->irc_snick = NULL;
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/*
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* Check command string
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*/
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if (strncmp(s, "PRIVMSG ", 8))
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return 0;
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i -= 8;
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s += 8;
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c = *s;
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ircp->irc_dnick = s;
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/*
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* Loosely check that the destination is a nickname of some sort
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*/
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if (!isalpha(c))
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return 0;
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for (; !isspace(c) && (i > 0); i--)
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c = *s++;
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if (i < 20)
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return 0;
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s++,
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i--;
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/*
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* Look for a ^A to start the DCC
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*/
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c = *s;
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if (c == ':') {
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s++;
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c = *s;
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}
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if (strncmp(s, "\001DCC ", 4))
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return 0;
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i -= 4;
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s += 4;
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/*
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* Check for a recognised DCC command
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*/
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for (j = 0, k = 0; ippr_irc_dcctypes[j]; j++) {
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k = MIN(strlen(ippr_irc_dcctypes[j]), i);
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if (!strncmp(ippr_irc_dcctypes[j], s, k))
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break;
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}
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if (!ippr_irc_dcctypes[j])
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return 0;
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ircp->irc_type = s;
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i -= k;
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s += k;
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if (i < 11)
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return 0;
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/*
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* Check for the arg
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*/
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c = *s;
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if (isspace(c))
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return 0;
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ircp->irc_arg = s;
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for (; (c != ' ') && (c != '\001') && (i > 0); i--)
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c = *s++;
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if (c == '\001') /* In reality a ^A can quote another ^A...*/
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return 0;
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if (i < 5)
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return 0;
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s++;
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i--;
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c = *s;
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if (!isdigit(c))
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return 0;
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ircp->irc_addr = s;
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/*
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* Get the IP#
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*/
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for (l = 0; isdigit(c) && (i > 0); i--) {
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l *= 10;
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l += c - '0';
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c = *s++;
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}
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if (i < 4)
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return 0;
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if (c != ' ')
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return 0;
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ircp->irc_ipnum = l;
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s++;
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i--;
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c = *s;
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if (!isdigit(c))
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return 0;
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/*
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* Get the port#
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*/
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for (l = 0; isdigit(c) && (i > 0); i--) {
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l *= 10;
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l += c - '0';
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c = *s++;
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}
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if (i < 3)
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return 0;
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if (strncmp(s, "\001\r\n", 3))
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return 0;
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s += 3;
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ircp->irc_len = s - buf;
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ircp->irc_port = l;
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return 1;
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}
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int ippr_irc_new(fin, aps, nat)
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fr_info_t *fin;
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ap_session_t *aps;
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nat_t *nat;
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{
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ircinfo_t *irc;
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KMALLOC(irc, ircinfo_t *);
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if (irc == NULL)
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return -1;
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fin = fin; /* LINT */
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nat = nat; /* LINT */
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aps->aps_data = irc;
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aps->aps_psiz = sizeof(ircinfo_t);
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bzero((char *)irc, sizeof(*irc));
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return 0;
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}
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int ippr_irc_send(fin, nat)
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fr_info_t *fin;
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nat_t *nat;
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{
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char ctcpbuf[IPF_IRCBUFSZ], newbuf[IPF_IRCBUFSZ];
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tcphdr_t *tcp, tcph, *tcp2 = &tcph;
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int off, inc = 0, i, dlen;
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size_t nlen = 0, olen;
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struct in_addr swip;
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u_short a5, sp;
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ircinfo_t *irc;
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fr_info_t fi;
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nat_t *nat2;
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u_int a1;
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ip_t *ip;
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mb_t *m;
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#ifdef MENTAT
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mb_t *m1;
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#endif
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m = fin->fin_m;
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ip = fin->fin_ip;
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tcp = (tcphdr_t *)fin->fin_dp;
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bzero(ctcpbuf, sizeof(ctcpbuf));
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off = (char *)tcp - MTOD(m, char *) + (TCP_OFF(tcp) << 2);
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dlen = MSGDSIZE(m) - off;
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if (dlen <= 0)
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return 0;
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COPYDATA(m, off, MIN(sizeof(ctcpbuf), dlen), ctcpbuf);
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if (dlen <= 0)
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return 0;
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ctcpbuf[sizeof(ctcpbuf) - 1] = '\0';
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*newbuf = '\0';
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irc = nat->nat_aps->aps_data;
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if (ippr_irc_complete(irc, ctcpbuf, dlen) == 0)
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return 0;
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/*
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* check that IP address in the PORT/PASV reply is the same as the
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* sender of the command - prevents using PORT for port scanning.
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*/
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if (irc->irc_ipnum != ntohl(nat->nat_inip.s_addr))
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return 0;
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a5 = irc->irc_port;
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/*
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* Calculate new address parts for the DCC command
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*/
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a1 = ntohl(ip->ip_src.s_addr);
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olen = irc->irc_len;
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i = irc->irc_addr - ctcpbuf;
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i++;
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(void) strncpy(newbuf, ctcpbuf, i);
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/* DO NOT change these! */
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#if defined(SNPRINTF) && defined(KERNEL)
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SNPRINTF(newbuf, sizeof(newbuf) - i, "%u %u\001\r\n", a1, a5);
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#else
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(void) sprintf(newbuf, "%u %u\001\r\n", a1, a5);
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#endif
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nlen = strlen(newbuf);
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inc = nlen - olen;
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if ((inc + ip->ip_len) > 65535)
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return 0;
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#ifdef MENTAT
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for (m1 = m; m1->b_cont; m1 = m1->b_cont)
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;
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if ((inc > 0) && (m1->b_datap->db_lim - m1->b_wptr < inc)) {
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mblk_t *nm;
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/* alloc enough to keep same trailer space for lower driver */
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nm = allocb(nlen, BPRI_MED);
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PANIC((!nm),("ippr_irc_out: allocb failed"));
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nm->b_band = m1->b_band;
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nm->b_wptr += nlen;
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m1->b_wptr -= olen;
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PANIC((m1->b_wptr < m1->b_rptr),
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("ippr_irc_out: cannot handle fragmented data block"));
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linkb(m1, nm);
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} else {
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# if SOLARIS && defined(ICK_VALID)
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if (m1->b_datap->db_struiolim == m1->b_wptr)
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m1->b_datap->db_struiolim += inc;
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m1->b_datap->db_struioflag &= ~STRUIO_IP;
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# endif
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m1->b_wptr += inc;
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}
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#else
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if (inc < 0)
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m_adj(m, inc);
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/* the mbuf chain will be extended if necessary by m_copyback() */
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#endif
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COPYBACK(m, off, nlen, newbuf);
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if (inc != 0) {
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#if defined(MENTAT) || defined(__sgi)
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register u_32_t sum1, sum2;
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sum1 = ip->ip_len;
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sum2 = ip->ip_len + inc;
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/* Because ~1 == -2, We really need ~1 == -1 */
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if (sum1 > sum2)
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sum2--;
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sum2 -= sum1;
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sum2 = (sum2 & 0xffff) + (sum2 >> 16);
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fix_outcksum(fin, &ip->ip_sum, sum2);
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#endif
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ip->ip_len += inc;
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}
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/*
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* Add skeleton NAT entry for connection which will come back the
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* other way.
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*/
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sp = htons(a5);
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/*
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* Don't allow the PORT command to specify a port < 1024 due to
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* security crap.
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*/
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if (ntohs(sp) < 1024)
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return 0;
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/*
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* The server may not make the connection back from port 20, but
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* it is the most likely so use it here to check for a conflicting
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* mapping.
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*/
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bcopy((caddr_t)fin, (caddr_t)&fi, sizeof(fi));
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fi.fin_data[0] = sp;
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fi.fin_data[1] = fin->fin_data[1];
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nat2 = nat_outlookup(fin, IPN_TCP, nat->nat_p, nat->nat_inip,
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ip->ip_dst);
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if (nat2 == NULL) {
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bcopy((caddr_t)fin, (caddr_t)&fi, sizeof(fi));
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bzero((char *)tcp2, sizeof(*tcp2));
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tcp2->th_win = htons(8192);
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tcp2->th_sport = sp;
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tcp2->th_dport = 0; /* XXX - don't specify remote port */
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fi.fin_data[0] = ntohs(sp);
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fi.fin_data[1] = 0;
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fi.fin_dp = (char *)tcp2;
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fi.fin_fr = &ircnatfr;
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fi.fin_dlen = sizeof(*tcp2);
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fi.fin_plen = fi.fin_hlen + sizeof(*tcp2);
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swip = ip->ip_src;
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ip->ip_src = nat->nat_inip;
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nat2 = nat_new(&fi, nat->nat_ptr, NULL,
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NAT_SLAVE|IPN_TCP|SI_W_DPORT, NAT_OUTBOUND);
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if (nat2 != NULL) {
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(void) nat_proto(&fi, nat2, 0);
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nat_update(&fi, nat2, nat2->nat_ptr);
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(void) fr_addstate(&fi, NULL, SI_W_DPORT);
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}
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ip->ip_src = swip;
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}
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return inc;
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}
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int ippr_irc_out(fin, aps, nat)
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fr_info_t *fin;
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ap_session_t *aps;
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nat_t *nat;
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{
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aps = aps; /* LINT */
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return ippr_irc_send(fin, nat);
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}
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