diff options
Diffstat (limited to 'contrib/ipfilter/ip_frag.c')
| -rw-r--r-- | contrib/ipfilter/ip_frag.c | 425 |
1 files changed, 425 insertions, 0 deletions
diff --git a/contrib/ipfilter/ip_frag.c b/contrib/ipfilter/ip_frag.c new file mode 100644 index 0000000..9b9bce3 --- /dev/null +++ b/contrib/ipfilter/ip_frag.c @@ -0,0 +1,425 @@ +/* + * (C)opyright 1993,1994,1995 by Darren Reed. + * + * Redistribution and use in source and binary forms are permitted + * provided that this notice is preserved and due credit is given + * to the original author and the contributors. + */ +#if !defined(lint) && defined(LIBC_SCCS) +static char sccsid[] = "@(#)ip_frag.c 1.11 3/24/96 (C) 1993-1995 Darren Reed"; +static char rcsid[] = "$Id: ip_frag.c,v 2.0.2.10 1997/05/24 07:36:23 darrenr Exp $"; +#endif + +#if !defined(_KERNEL) && !defined(KERNEL) +# include <string.h> +# include <stdlib.h> +#endif +#include <sys/errno.h> +#include <sys/types.h> +#include <sys/param.h> +#include <sys/time.h> +#include <sys/file.h> +#if defined(KERNEL) && (__FreeBSD_version >= 220000) +#include <sys/filio.h> +#include <sys/fcntl.h> +#else +#include <sys/ioctl.h> +#endif +#include <sys/uio.h> +#include <sys/protosw.h> +#include <sys/socket.h> +#ifdef _KERNEL +# include <sys/systm.h> +#endif +#if !defined(__SVR4) && !defined(__svr4__) +# include <sys/mbuf.h> +#else +# include <sys/byteorder.h> +# include <sys/dditypes.h> +# include <sys/stream.h> +# include <sys/kmem.h> +#endif + +#include <net/if.h> +#ifdef sun +#include <net/af.h> +#endif +#include <net/route.h> +#include <netinet/in.h> +#include <netinet/in_systm.h> +#include <netinet/ip.h> +#include <netinet/ip_var.h> +#include <netinet/tcp.h> +#include <netinet/udp.h> +#include <netinet/tcpip.h> +#include <netinet/ip_icmp.h> +#include "netinet/ip_compat.h" +#include "netinet/ip_fil.h" +#include "netinet/ip_proxy.h" +#include "netinet/ip_nat.h" +#include "netinet/ip_frag.h" +#include "netinet/ip_state.h" + +ipfr_t *ipfr_heads[IPFT_SIZE]; +ipfr_t *ipfr_nattab[IPFT_SIZE]; +ipfrstat_t ipfr_stats; +u_long ipfr_inuse = 0, + fr_ipfrttl = 120; /* 60 seconds */ +#ifdef _KERNEL +extern int ipfr_timer_id; +#endif +#if SOLARIS && defined(_KERNEL) +extern kmutex_t ipf_frag; +extern kmutex_t ipf_natfrag; +extern kmutex_t ipf_nat; +#endif + + +static ipfr_t *ipfr_new __P((ip_t *, fr_info_t *, int, ipfr_t **)); +static ipfr_t *ipfr_lookup __P((ip_t *, fr_info_t *, ipfr_t **)); + + +ipfrstat_t *ipfr_fragstats() +{ + ipfr_stats.ifs_table = ipfr_heads; + ipfr_stats.ifs_nattab = ipfr_nattab; + ipfr_stats.ifs_inuse = ipfr_inuse; + return &ipfr_stats; +} + + +/* + * add a new entry to the fragment cache, registering it as having come + * through this box, with the result of the filter operation. + */ +static ipfr_t *ipfr_new(ip, fin, pass, table) +ip_t *ip; +fr_info_t *fin; +int pass; +ipfr_t *table[]; +{ + ipfr_t **fp, *fr, frag; + u_int idx; + + frag.ipfr_p = ip->ip_p; + idx = ip->ip_p; + frag.ipfr_id = ip->ip_id; + idx += ip->ip_id; + frag.ipfr_tos = ip->ip_tos; + frag.ipfr_src.s_addr = ip->ip_src.s_addr; + idx += ip->ip_src.s_addr; + frag.ipfr_dst.s_addr = ip->ip_dst.s_addr; + idx += ip->ip_dst.s_addr; + idx *= 127; + idx %= IPFT_SIZE; + + /* + * first, make sure it isn't already there... + */ + for (fp = &table[idx]; (fr = *fp); fp = &fr->ipfr_next) + if (!bcmp((char *)&frag.ipfr_src, (char *)&fr->ipfr_src, + IPFR_CMPSZ)) { + ipfr_stats.ifs_exists++; + MUTEX_EXIT(&ipf_frag); + return NULL; + } + + /* + * allocate some memory, if possible, if not, just record that we + * failed to do so. + */ + KMALLOC(fr, ipfr_t *, sizeof(*fr)); + if (fr == NULL) { + ipfr_stats.ifs_nomem++; + MUTEX_EXIT(&ipf_frag); + return NULL; + } + + /* + * Instert the fragment into the fragment table, copy the struct used + * in the search using bcopy rather than reassign each field. + * Set the ttl to the default and mask out logging from "pass" + */ + if ((fr->ipfr_next = table[idx])) + table[idx]->ipfr_prev = fr; + fr->ipfr_prev = NULL; + fr->ipfr_data = NULL; + table[idx] = fr; + bcopy((char *)&frag.ipfr_src, (char *)&fr->ipfr_src, IPFR_CMPSZ); + fr->ipfr_ttl = fr_ipfrttl; + fr->ipfr_pass = pass & ~(FR_LOGFIRST|FR_LOG); + /* + * Compute the offset of the expected start of the next packet. + */ + fr->ipfr_off = (ip->ip_off & 0x1fff) + (fin->fin_dlen >> 3); + ipfr_stats.ifs_new++; + ipfr_inuse++; + return fr; +} + + +int ipfr_newfrag(ip, fin, pass) +ip_t *ip; +fr_info_t *fin; +int pass; +{ + ipfr_t *ipf; + + MUTEX_ENTER(&ipf_frag); + ipf = ipfr_new(ip, fin, pass, ipfr_heads); + MUTEX_EXIT(&ipf_frag); + return ipf ? 0 : -1; +} + + +int ipfr_nat_newfrag(ip, fin, pass, nat) +ip_t *ip; +fr_info_t *fin; +int pass; +nat_t *nat; +{ + ipfr_t *ipf; + + MUTEX_ENTER(&ipf_natfrag); + if ((ipf = ipfr_new(ip, fin, pass, ipfr_nattab))) { + ipf->ipfr_data = nat; + nat->nat_frag = ipf; + } + MUTEX_EXIT(&ipf_natfrag); + return ipf ? 0 : -1; +} + + +/* + * check the fragment cache to see if there is already a record of this packet + * with its filter result known. + */ +static ipfr_t *ipfr_lookup(ip, fin, table) +ip_t *ip; +fr_info_t *fin; +ipfr_t *table[]; +{ + ipfr_t *f, frag; + u_int idx; + int ret; + + /* + * For fragments, we record protocol, packet id, TOS and both IP#'s + * (these should all be the same for all fragments of a packet). + * + * build up a hash value to index the table with. + */ + frag.ipfr_p = ip->ip_p; + idx = ip->ip_p; + frag.ipfr_id = ip->ip_id; + idx += ip->ip_id; + frag.ipfr_tos = ip->ip_tos; + frag.ipfr_src.s_addr = ip->ip_src.s_addr; + idx += ip->ip_src.s_addr; + frag.ipfr_dst.s_addr = ip->ip_dst.s_addr; + idx += ip->ip_dst.s_addr; + idx *= 127; + idx %= IPFT_SIZE; + + /* + * check the table, careful to only compare the right amount of data + */ + for (f = table[idx]; f; f = f->ipfr_next) + if (!bcmp((char *)&frag.ipfr_src, (char *)&f->ipfr_src, + IPFR_CMPSZ)) { + u_short atoff, off; + + if (f != table[idx]) { + /* + * move fragment info. to the top of the list + * to speed up searches. + */ + if ((f->ipfr_prev->ipfr_next = f->ipfr_next)) + f->ipfr_next->ipfr_prev = f->ipfr_prev; + f->ipfr_next = table[idx]; + table[idx]->ipfr_prev = f; + f->ipfr_prev = NULL; + table[idx] = f; + } + off = ip->ip_off; + atoff = (off & 0x1fff) - (fin->fin_dlen >> 3); + /* + * If we've follwed the fragments, and this is the + * last (in order), shrink expiration time. + */ + if (atoff == f->ipfr_off) { + if (!(off & IP_MF)) + f->ipfr_ttl = 1; + else + f->ipfr_off = off; + } + ipfr_stats.ifs_hits++; + return f; + } + return NULL; +} + + +/* + * functional interface for normal lookups of the fragment cache + */ +nat_t *ipfr_nat_knownfrag(ip, fin) +ip_t *ip; +fr_info_t *fin; +{ + nat_t *nat; + ipfr_t *ipf; + + MUTEX_ENTER(&ipf_natfrag); + ipf = ipfr_lookup(ip, fin, ipfr_heads); + nat = ipf ? ipf->ipfr_data : NULL; + MUTEX_EXIT(&ipf_natfrag); + return nat; +} + + +/* + * functional interface for NAT lookups of the NAT fragment cache + */ +int ipfr_knownfrag(ip, fin) +ip_t *ip; +fr_info_t *fin; +{ + int ret; + ipfr_t *ipf; + + MUTEX_ENTER(&ipf_frag); + ipf = ipfr_lookup(ip, fin, ipfr_heads); + ret = ipf ? ipf->ipfr_pass : 0; + MUTEX_EXIT(&ipf_frag); + return ret; +} + + +/* + * Free memory in use by fragment state info. kept. + */ +void ipfr_unload() +{ + ipfr_t **fp, *fr; + nat_t *nat; + int idx; +#if !SOLARIS && defined(_KERNEL) + int s; +#endif + + SPLNET(s); + MUTEX_ENTER(&ipf_frag); + for (idx = IPFT_SIZE - 1; idx >= 0; idx--) + for (fp = &ipfr_heads[idx]; (fr = *fp); ) { + *fp = fr->ipfr_next; + KFREE(fr); + } + MUTEX_EXIT(&ipf_frag); + + MUTEX_ENTER(&ipf_nat); + MUTEX_ENTER(&ipf_natfrag); + for (idx = IPFT_SIZE - 1; idx >= 0; idx--) + for (fp = &ipfr_nattab[idx]; (fr = *fp); ) { + *fp = fr->ipfr_next; + if ((nat = (nat_t *)fr->ipfr_data)) { + if (nat->nat_frag == fr) + nat->nat_frag = NULL; + } + KFREE(fr); + } + MUTEX_EXIT(&ipf_natfrag); + MUTEX_EXIT(&ipf_nat); + SPLX(s); +} + + +#ifdef _KERNEL +/* + * Slowly expire held state for fragments. Timeouts are set * in expectation + * of this being called twice per second. + */ +# if (BSD >= 199306) || SOLARIS +void ipfr_slowtimer() +# else +int ipfr_slowtimer() +# endif +{ + ipfr_t **fp, *fr; + nat_t *nat; + int s, idx; + + MUTEX_ENTER(&ipf_frag); + SPLNET(s); + + /* + * Go through the entire table, looking for entries to expire, + * decreasing the ttl by one for each entry. If it reaches 0, + * remove it from the chain and free it. + */ + for (idx = IPFT_SIZE - 1; idx >= 0; idx--) + for (fp = &ipfr_heads[idx]; (fr = *fp); ) { + --fr->ipfr_ttl; + if (fr->ipfr_ttl == 0) { + if (fr->ipfr_prev) + fr->ipfr_prev->ipfr_next = + fr->ipfr_next; + if (fr->ipfr_next) + fr->ipfr_next->ipfr_prev = + fr->ipfr_prev; + *fp = fr->ipfr_next; + ipfr_stats.ifs_expire++; + ipfr_inuse--; + KFREE(fr); + } else + fp = &fr->ipfr_next; + } + MUTEX_EXIT(&ipf_frag); + + /* + * Same again for the NAT table, except that if the structure also + * still points to a NAT structure, and the NAT structure points back + * at the one to be free'd, NULL the reference from the NAT struct. + * NOTE: We need to grab both mutex's early, and in this order so as + * to prevent a deadlock if both try to expire at the same time. + */ + MUTEX_ENTER(&ipf_nat); + MUTEX_ENTER(&ipf_natfrag); + for (idx = IPFT_SIZE - 1; idx >= 0; idx--) + for (fp = &ipfr_nattab[idx]; (fr = *fp); ) { + --fr->ipfr_ttl; + if (fr->ipfr_ttl == 0) { + if (fr->ipfr_prev) + fr->ipfr_prev->ipfr_next = + fr->ipfr_next; + if (fr->ipfr_next) + fr->ipfr_next->ipfr_prev = + fr->ipfr_prev; + *fp = fr->ipfr_next; + ipfr_stats.ifs_expire++; + ipfr_inuse--; + if ((nat = (nat_t *)fr->ipfr_data)) { + if (nat->nat_frag == fr) + nat->nat_frag = NULL; + } + KFREE(fr); + } else + fp = &fr->ipfr_next; + } + MUTEX_EXIT(&ipf_natfrag); + MUTEX_EXIT(&ipf_nat); + SPLX(s); +# if SOLARIS + fr_timeoutstate(); + ip_natexpire(); + ipfr_timer_id = timeout(ipfr_slowtimer, NULL, drv_usectohz(500000)); +# else + fr_timeoutstate(); + ip_natexpire(); + ip_slowtimo(); +# if BSD < 199306 + return 0; +# endif +# endif +} +#endif /* defined(_KERNEL) */ |
