343 lines
7.0 KiB
C
343 lines
7.0 KiB
C
/*
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* Copyright (C) 1997 by Darren Reed.
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*
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* Redistribution and use in source and binary forms are permitted
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* provided that this notice is preserved and due credit is given
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* to the original author and the contributors.
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*/
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#if !defined(lint)
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static const char rcsid[] = "@(#)$Id: ip_proxy.c,v 1.3 1998/06/20 18:37:50 peter Exp $";
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#endif
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#if defined(__FreeBSD__) && defined(KERNEL) && !defined(_KERNEL)
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# define _KERNEL
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#endif
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#if !defined(_KERNEL) && !defined(KERNEL)
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# include <stdio.h>
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# include <string.h>
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# include <stdlib.h>
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#endif
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#include <sys/errno.h>
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#include <sys/types.h>
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#include <sys/param.h>
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#include <sys/time.h>
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#include <sys/file.h>
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#if !defined(__FreeBSD__)
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# include <sys/ioctl.h>
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#endif
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#include <sys/fcntl.h>
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#include <sys/uio.h>
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#ifndef linux
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# include <sys/protosw.h>
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#endif
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#include <sys/socket.h>
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#if defined(_KERNEL)
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# if !defined(linux)
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# include <sys/systm.h>
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# else
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# include <linux/string.h>
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# endif
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#endif
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#if !defined(__SVR4) && !defined(__svr4__)
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# ifndef linux
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# include <sys/mbuf.h>
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# endif
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#else
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# include <sys/byteorder.h>
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# include <sys/dditypes.h>
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# include <sys/stream.h>
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# include <sys/kmem.h>
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#endif
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#if __FreeBSD__ > 2
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# include <sys/queue.h>
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# include <sys/malloc.h>
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#endif
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#include <net/if.h>
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#ifdef sun
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# include <net/af.h>
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#endif
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#include <net/route.h>
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#include <netinet/in.h>
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#include <netinet/in_systm.h>
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#include <netinet/ip.h>
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#ifndef linux
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# include <netinet/ip_var.h>
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#endif
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#include <netinet/tcp.h>
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#include <netinet/udp.h>
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#include <netinet/ip_icmp.h>
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#include "netinet/ip_compat.h"
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#include <netinet/tcpip.h>
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#include "netinet/ip_fil.h"
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#include "netinet/ip_proxy.h"
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#include "netinet/ip_nat.h"
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#include "netinet/ip_state.h"
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#ifndef MIN
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#define MIN(a,b) (((a)<(b))?(a):(b))
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#endif
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static ap_session_t *ap_find __P((ip_t *, tcphdr_t *));
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static ap_session_t *ap_new_session __P((aproxy_t *, ip_t *, tcphdr_t *,
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fr_info_t *, nat_t *));
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static int ap_matchsrcdst __P((ap_session_t *aps, struct in_addr src,
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struct in_addr dst, void *tcp, u_short sport,
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u_short dport));
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#define AP_SESS_SIZE 53
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#if defined(_KERNEL) && !defined(linux)
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#include "netinet/ip_ftp_pxy.c"
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#endif
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ap_session_t *ap_sess_tab[AP_SESS_SIZE];
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aproxy_t ap_proxies[] = {
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#ifdef IPF_FTP_PROXY
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{ "ftp", (char)IPPROTO_TCP, 0, 0, ippr_ftp_init, ippr_ftp_in, ippr_ftp_out },
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#endif
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{ "", '\0', 0, 0, NULL, NULL }
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};
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int ap_ok(ip, tcp, nat)
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ip_t *ip;
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tcphdr_t *tcp;
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ipnat_t *nat;
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{
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aproxy_t *apr = nat->in_apr;
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u_short dport = nat->in_dport;
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if (!apr || (apr && (apr->apr_flags & APR_DELETE)) ||
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(ip->ip_p != apr->apr_p))
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return 0;
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if ((tcp && (tcp->th_dport != dport)) || (!tcp && dport))
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return 0;
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return 1;
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}
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static int
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ap_matchsrcdst(aps, src, dst, tcp, sport, dport)
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ap_session_t *aps;
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struct in_addr src, dst;
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void *tcp;
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u_short sport, dport;
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{
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if (aps->aps_dst.s_addr == dst.s_addr) {
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if ((aps->aps_src.s_addr == src.s_addr) &&
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(!tcp || ((sport == aps->aps_sport) &&
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(dport == aps->aps_dport))))
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return 1;
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} else if (aps->aps_dst.s_addr == src.s_addr) {
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if ((aps->aps_src.s_addr == dst.s_addr) &&
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(!tcp || ((sport == aps->aps_dport) &&
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(dport == aps->aps_sport))))
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return 1;
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}
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return 0;
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}
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static ap_session_t *ap_find(ip, tcp)
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ip_t *ip;
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tcphdr_t *tcp;
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{
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register u_char p = ip->ip_p;
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register ap_session_t *aps;
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register u_short sp, dp;
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register u_long hv;
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struct in_addr src, dst;
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src = ip->ip_src, dst = ip->ip_dst;
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sp = dp = 0; /* XXX gcc -Wunitialized */
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hv = ip->ip_src.s_addr ^ ip->ip_dst.s_addr;
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hv *= 651733;
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if (tcp) {
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sp = tcp->th_sport;
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dp = tcp->th_dport;
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hv ^= (sp + dp);
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hv *= 5;
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}
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hv %= AP_SESS_SIZE;
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for (aps = ap_sess_tab[hv]; aps; aps = aps->aps_next)
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if ((aps->aps_p == p) &&
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ap_matchsrcdst(aps, src, dst, tcp, sp, dp))
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break;
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return aps;
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}
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/*
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* Allocate a new application proxy structure and fill it in with the
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* relevant details. call the init function once complete, prior to
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* returning.
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*/
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static ap_session_t *ap_new_session(apr, ip, tcp, fin, nat)
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aproxy_t *apr;
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ip_t *ip;
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tcphdr_t *tcp;
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fr_info_t *fin;
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nat_t *nat;
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{
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register ap_session_t *aps;
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u_short dport;
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u_long hv;
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if (!apr || (apr && (apr->apr_flags & APR_DELETE)) ||
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(ip->ip_p != apr->apr_p))
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return NULL;
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dport = nat->nat_ptr->in_dport;
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if ((tcp && (tcp->th_dport != dport)) || (!tcp && dport))
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return NULL;
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hv = ip->ip_src.s_addr ^ ip->ip_dst.s_addr;
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hv *= 651733;
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if (tcp) {
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hv ^= (tcp->th_sport + tcp->th_dport);
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hv *= 5;
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}
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hv %= AP_SESS_SIZE;
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KMALLOC(aps, ap_session_t *, sizeof(*aps));
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if (!aps)
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return NULL;
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bzero((char *)aps, sizeof(*aps));
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aps->aps_apr = apr;
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aps->aps_src = ip->ip_src;
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aps->aps_dst = ip->ip_dst;
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aps->aps_p = ip->ip_p;
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aps->aps_tout = 1200; /* XXX */
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if (tcp) {
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aps->aps_sport = tcp->th_sport;
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aps->aps_dport = tcp->th_dport;
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}
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aps->aps_data = NULL;
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aps->aps_psiz = 0;
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aps->aps_next = ap_sess_tab[hv];
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ap_sess_tab[hv] = aps;
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(void) (*apr->apr_init)(fin, ip, tcp, aps, nat);
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return aps;
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}
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/*
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* check to see if a packet should be passed through an active proxy routine
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* if one has been setup for it.
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*/
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int ap_check(ip, tcp, fin, nat)
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ip_t *ip;
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tcphdr_t *tcp;
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fr_info_t *fin;
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nat_t *nat;
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{
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ap_session_t *aps;
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aproxy_t *apr;
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int err;
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if (!(fin->fin_fi.fi_fl & FI_TCPUDP))
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tcp = NULL;
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if ((aps = ap_find(ip, tcp)) ||
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(aps = ap_new_session(nat->nat_ptr->in_apr, ip, tcp, fin, nat))) {
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if (ip->ip_p == IPPROTO_TCP) {
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/*
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* verify that the checksum is correct. If not, then
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* don't do anything with this packet.
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*/
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if (tcp->th_sum != fr_tcpsum(*(mb_t **)fin->fin_mp,
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ip, tcp, ip->ip_len)) {
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frstats[fin->fin_out].fr_tcpbad++;
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return -1;
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}
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fr_tcp_age(&aps->aps_tout, aps->aps_state, ip, fin,
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tcp->th_sport == aps->aps_sport);
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}
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apr = aps->aps_apr;
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err = 0;
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if (fin->fin_out) {
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if (apr->apr_outpkt)
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err = (*apr->apr_outpkt)(fin, ip, tcp,
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aps, nat);
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} else {
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if (apr->apr_inpkt)
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err = (*apr->apr_inpkt)(fin, ip, tcp,
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aps, nat);
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}
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if (err == 2) {
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tcp->th_sum = fr_tcpsum(*(mb_t **)fin->fin_mp, ip,
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tcp, ip->ip_len);
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err = 0;
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}
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return err;
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}
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return -1;
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}
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aproxy_t *ap_match(pr, name)
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u_char pr;
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char *name;
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{
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aproxy_t *ap;
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for (ap = ap_proxies; ap->apr_p; ap++)
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if ((ap->apr_p == pr) &&
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!strncmp(name, ap->apr_label, sizeof(ap->apr_label))) {
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ap->apr_ref++;
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return ap;
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}
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return NULL;
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}
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void ap_free(ap)
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aproxy_t *ap;
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{
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ap->apr_ref--;
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}
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void aps_free(aps)
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ap_session_t *aps;
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{
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if (aps->aps_data && aps->aps_psiz)
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KFREES(aps->aps_data, aps->aps_psiz);
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KFREE(aps);
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}
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void ap_unload()
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{
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ap_session_t *aps;
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int i;
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for (i = 0; i < AP_SESS_SIZE; i++)
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while ((aps = ap_sess_tab[i])) {
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ap_sess_tab[i] = aps->aps_next;
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aps_free(aps);
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}
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}
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void ap_expire()
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{
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ap_session_t *aps, **apsp;
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int i;
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for (i = 0; i < AP_SESS_SIZE; i++)
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for (apsp = &ap_sess_tab[i]; (aps = *apsp); ) {
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aps->aps_tout--;
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if (!aps->aps_tout) {
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ap_sess_tab[i] = aps->aps_next;
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aps_free(aps);
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*apsp = aps->aps_next;
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} else
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apsp = &aps->aps_next;
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}
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}
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