468 lines
10 KiB
C
468 lines
10 KiB
C
/*
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* Copyright (C) 1993-1997 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 sccsid[] = "@(#)ip_frag.c 1.11 3/24/96 (C) 1993-1995 Darren Reed";
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static const char rcsid[] = "@(#)$Id: ip_frag.c,v 1.2 1998/03/21 11:34:06 peter Exp $";
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#endif
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#if !defined(_KERNEL) && defined(KERNEL)
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#define _KERNEL
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#endif
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#define __FreeBSD_version 300000 /* it's a hack, but close enough */
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#if !defined(_KERNEL) && !defined(KERNEL)
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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(KERNEL) && (__FreeBSD_version >= 220000)
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#include <sys/filio.h>
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#include <sys/fcntl.h>
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#include <sys/malloc.h>
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#else
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#include <sys/ioctl.h>
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#endif
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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) && !defined(linux)
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# include <sys/systm.h>
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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 defined(KERNEL) && (__FreeBSD_version >= 300000)
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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_frag.h"
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#include "netinet/ip_state.h"
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#include "netinet/ip_auth.h"
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static ipfr_t *ipfr_heads[IPFT_SIZE];
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static ipfr_t *ipfr_nattab[IPFT_SIZE];
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static ipfrstat_t ipfr_stats;
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static int ipfr_inuse = 0;
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int fr_ipfrttl = 120; /* 60 seconds */
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#ifdef _KERNEL
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extern int ipfr_timer_id;
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#endif
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#if (SOLARIS || defined(__sgi)) && defined(_KERNEL)
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extern kmutex_t ipf_frag;
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extern kmutex_t ipf_natfrag;
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extern kmutex_t ipf_nat;
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#endif
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static ipfr_t *ipfr_new __P((ip_t *, fr_info_t *, int, ipfr_t **));
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static ipfr_t *ipfr_lookup __P((ip_t *, fr_info_t *, ipfr_t **));
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ipfrstat_t *ipfr_fragstats()
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{
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ipfr_stats.ifs_table = ipfr_heads;
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ipfr_stats.ifs_nattab = ipfr_nattab;
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ipfr_stats.ifs_inuse = ipfr_inuse;
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return &ipfr_stats;
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}
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/*
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* add a new entry to the fragment cache, registering it as having come
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* through this box, with the result of the filter operation.
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*/
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static ipfr_t *ipfr_new(ip, fin, pass, table)
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ip_t *ip;
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fr_info_t *fin;
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int pass;
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ipfr_t *table[];
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{
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ipfr_t **fp, *fr, frag;
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u_int idx;
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frag.ipfr_p = ip->ip_p;
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idx = ip->ip_p;
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frag.ipfr_id = ip->ip_id;
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idx += ip->ip_id;
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frag.ipfr_tos = ip->ip_tos;
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frag.ipfr_src.s_addr = ip->ip_src.s_addr;
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idx += ip->ip_src.s_addr;
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frag.ipfr_dst.s_addr = ip->ip_dst.s_addr;
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idx += ip->ip_dst.s_addr;
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idx *= 127;
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idx %= IPFT_SIZE;
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/*
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* first, make sure it isn't already there...
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*/
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for (fp = &table[idx]; (fr = *fp); fp = &fr->ipfr_next)
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if (!bcmp((char *)&frag.ipfr_src, (char *)&fr->ipfr_src,
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IPFR_CMPSZ)) {
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ipfr_stats.ifs_exists++;
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return NULL;
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}
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/*
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* allocate some memory, if possible, if not, just record that we
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* failed to do so.
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*/
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KMALLOC(fr, ipfr_t *, sizeof(*fr));
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if (fr == NULL) {
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ipfr_stats.ifs_nomem++;
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return NULL;
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}
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/*
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* Instert the fragment into the fragment table, copy the struct used
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* in the search using bcopy rather than reassign each field.
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* Set the ttl to the default and mask out logging from "pass"
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*/
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if ((fr->ipfr_next = table[idx]))
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table[idx]->ipfr_prev = fr;
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fr->ipfr_prev = NULL;
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fr->ipfr_data = NULL;
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table[idx] = fr;
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bcopy((char *)&frag.ipfr_src, (char *)&fr->ipfr_src, IPFR_CMPSZ);
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fr->ipfr_ttl = fr_ipfrttl;
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fr->ipfr_pass = pass & ~(FR_LOGFIRST|FR_LOG);
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/*
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* Compute the offset of the expected start of the next packet.
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*/
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fr->ipfr_off = (ip->ip_off & 0x1fff) + (fin->fin_dlen >> 3);
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ipfr_stats.ifs_new++;
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ipfr_inuse++;
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return fr;
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}
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int ipfr_newfrag(ip, fin, pass)
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ip_t *ip;
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fr_info_t *fin;
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int pass;
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{
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ipfr_t *ipf;
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MUTEX_ENTER(&ipf_frag);
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ipf = ipfr_new(ip, fin, pass, ipfr_heads);
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MUTEX_EXIT(&ipf_frag);
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return ipf ? 0 : -1;
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}
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int ipfr_nat_newfrag(ip, fin, pass, nat)
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ip_t *ip;
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fr_info_t *fin;
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int pass;
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nat_t *nat;
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{
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ipfr_t *ipf;
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MUTEX_ENTER(&ipf_natfrag);
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if ((ipf = ipfr_new(ip, fin, pass, ipfr_nattab))) {
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ipf->ipfr_data = nat;
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nat->nat_data = ipf;
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}
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MUTEX_EXIT(&ipf_natfrag);
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return ipf ? 0 : -1;
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}
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/*
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* check the fragment cache to see if there is already a record of this packet
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* with its filter result known.
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*/
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static ipfr_t *ipfr_lookup(ip, fin, table)
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ip_t *ip;
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fr_info_t *fin;
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ipfr_t *table[];
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{
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ipfr_t *f, frag;
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u_int idx;
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/*
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* For fragments, we record protocol, packet id, TOS and both IP#'s
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* (these should all be the same for all fragments of a packet).
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*
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* build up a hash value to index the table with.
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*/
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frag.ipfr_p = ip->ip_p;
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idx = ip->ip_p;
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frag.ipfr_id = ip->ip_id;
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idx += ip->ip_id;
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frag.ipfr_tos = ip->ip_tos;
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frag.ipfr_src.s_addr = ip->ip_src.s_addr;
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idx += ip->ip_src.s_addr;
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frag.ipfr_dst.s_addr = ip->ip_dst.s_addr;
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idx += ip->ip_dst.s_addr;
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idx *= 127;
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idx %= IPFT_SIZE;
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/*
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* check the table, careful to only compare the right amount of data
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*/
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for (f = table[idx]; f; f = f->ipfr_next)
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if (!bcmp((char *)&frag.ipfr_src, (char *)&f->ipfr_src,
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IPFR_CMPSZ)) {
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u_short atoff, off;
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if (f != table[idx]) {
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/*
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* move fragment info. to the top of the list
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* to speed up searches.
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*/
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if ((f->ipfr_prev->ipfr_next = f->ipfr_next))
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f->ipfr_next->ipfr_prev = f->ipfr_prev;
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f->ipfr_next = table[idx];
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table[idx]->ipfr_prev = f;
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f->ipfr_prev = NULL;
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table[idx] = f;
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}
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off = ip->ip_off;
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atoff = off + (fin->fin_dlen >> 3);
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/*
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* If we've follwed the fragments, and this is the
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* last (in order), shrink expiration time.
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*/
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if ((off & 0x1fff) == f->ipfr_off) {
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if (!(off & IP_MF))
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f->ipfr_ttl = 1;
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else
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f->ipfr_off = atoff;
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}
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ipfr_stats.ifs_hits++;
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return f;
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}
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return NULL;
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}
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/*
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* functional interface for NAT lookups of the NAT fragment cache
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*/
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nat_t *ipfr_nat_knownfrag(ip, fin)
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ip_t *ip;
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fr_info_t *fin;
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{
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nat_t *nat;
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ipfr_t *ipf;
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MUTEX_ENTER(&ipf_natfrag);
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ipf = ipfr_lookup(ip, fin, ipfr_nattab);
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if (ipf) {
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nat = ipf->ipfr_data;
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/*
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* This is the last fragment for this packet.
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*/
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if (ipf->ipfr_ttl == 1) {
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nat->nat_data = NULL;
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ipf->ipfr_data = NULL;
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}
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} else
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nat = NULL;
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MUTEX_EXIT(&ipf_natfrag);
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return nat;
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}
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/*
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* functional interface for normal lookups of the fragment cache
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*/
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int ipfr_knownfrag(ip, fin)
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ip_t *ip;
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fr_info_t *fin;
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{
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int ret;
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ipfr_t *ipf;
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MUTEX_ENTER(&ipf_frag);
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ipf = ipfr_lookup(ip, fin, ipfr_heads);
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ret = ipf ? ipf->ipfr_pass : 0;
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MUTEX_EXIT(&ipf_frag);
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return ret;
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}
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/*
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* forget any references to this external object.
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*/
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void ipfr_forget(nat)
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void *nat;
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{
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ipfr_t *fr;
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int idx;
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MUTEX_ENTER(&ipf_natfrag);
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for (idx = IPFT_SIZE - 1; idx >= 0; idx--)
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for (fr = ipfr_heads[idx]; fr; fr = fr->ipfr_next)
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if (fr->ipfr_data == nat)
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fr->ipfr_data = NULL;
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MUTEX_EXIT(&ipf_natfrag);
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}
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/*
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* Free memory in use by fragment state info. kept.
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*/
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void ipfr_unload()
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{
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ipfr_t **fp, *fr;
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nat_t *nat;
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int idx;
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MUTEX_ENTER(&ipf_frag);
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for (idx = IPFT_SIZE - 1; idx >= 0; idx--)
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for (fp = &ipfr_heads[idx]; (fr = *fp); ) {
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*fp = fr->ipfr_next;
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KFREE(fr);
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}
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MUTEX_EXIT(&ipf_frag);
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MUTEX_ENTER(&ipf_nat);
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MUTEX_ENTER(&ipf_natfrag);
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for (idx = IPFT_SIZE - 1; idx >= 0; idx--)
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for (fp = &ipfr_nattab[idx]; (fr = *fp); ) {
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*fp = fr->ipfr_next;
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if ((nat = (nat_t *)fr->ipfr_data)) {
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if (nat->nat_data == fr)
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nat->nat_data = NULL;
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}
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KFREE(fr);
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}
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MUTEX_EXIT(&ipf_natfrag);
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MUTEX_EXIT(&ipf_nat);
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}
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#ifdef _KERNEL
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/*
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* Slowly expire held state for fragments. Timeouts are set * in expectation
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* of this being called twice per second.
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*/
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# if (BSD >= 199306) || SOLARIS || defined(__sgi)
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void ipfr_slowtimer()
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# else
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int ipfr_slowtimer()
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# endif
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{
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ipfr_t **fp, *fr;
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nat_t *nat;
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int s, idx;
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#ifdef __sgi
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ipfilter_sgi_intfsync();
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#endif
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SPL_NET(s);
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MUTEX_ENTER(&ipf_frag);
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/*
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* Go through the entire table, looking for entries to expire,
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* decreasing the ttl by one for each entry. If it reaches 0,
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* remove it from the chain and free it.
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*/
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for (idx = IPFT_SIZE - 1; idx >= 0; idx--)
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for (fp = &ipfr_heads[idx]; (fr = *fp); ) {
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--fr->ipfr_ttl;
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if (fr->ipfr_ttl == 0) {
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if (fr->ipfr_prev)
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fr->ipfr_prev->ipfr_next =
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fr->ipfr_next;
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if (fr->ipfr_next)
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fr->ipfr_next->ipfr_prev =
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fr->ipfr_prev;
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*fp = fr->ipfr_next;
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ipfr_stats.ifs_expire++;
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ipfr_inuse--;
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KFREE(fr);
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} else
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fp = &fr->ipfr_next;
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}
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MUTEX_EXIT(&ipf_frag);
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/*
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* Same again for the NAT table, except that if the structure also
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* still points to a NAT structure, and the NAT structure points back
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* at the one to be free'd, NULL the reference from the NAT struct.
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* NOTE: We need to grab both mutex's early, and in this order so as
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* to prevent a deadlock if both try to expire at the same time.
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*/
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MUTEX_ENTER(&ipf_nat);
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MUTEX_ENTER(&ipf_natfrag);
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for (idx = IPFT_SIZE - 1; idx >= 0; idx--)
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for (fp = &ipfr_nattab[idx]; (fr = *fp); ) {
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--fr->ipfr_ttl;
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if (fr->ipfr_ttl == 0) {
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if (fr->ipfr_prev)
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fr->ipfr_prev->ipfr_next =
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fr->ipfr_next;
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if (fr->ipfr_next)
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fr->ipfr_next->ipfr_prev =
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fr->ipfr_prev;
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*fp = fr->ipfr_next;
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ipfr_stats.ifs_expire++;
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ipfr_inuse--;
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if ((nat = (nat_t *)fr->ipfr_data)) {
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if (nat->nat_data == fr)
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nat->nat_data = NULL;
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}
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KFREE(fr);
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} else
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fp = &fr->ipfr_next;
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}
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MUTEX_EXIT(&ipf_natfrag);
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MUTEX_EXIT(&ipf_nat);
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SPL_X(s);
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fr_timeoutstate();
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ip_natexpire();
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fr_authexpire();
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# if SOLARIS
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ipfr_timer_id = timeout(ipfr_slowtimer, NULL, drv_usectohz(500000));
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# else
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# ifndef linux
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ip_slowtimo();
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# endif
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# if (BSD < 199306) && !defined(__sgi)
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return 0;
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# endif
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# endif
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}
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#endif /* defined(_KERNEL) */
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