diff options
Diffstat (limited to 'sys/netinet/ip_state.c')
| -rw-r--r-- | sys/netinet/ip_state.c | 1105 |
1 files changed, 1105 insertions, 0 deletions
diff --git a/sys/netinet/ip_state.c b/sys/netinet/ip_state.c new file mode 100644 index 0000000..95e8793 --- /dev/null +++ b/sys/netinet/ip_state.c @@ -0,0 +1,1105 @@ +/* + * Copyright (C) 1995-1998 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) +static const char sccsid[] = "@(#)ip_state.c 1.8 6/5/96 (C) 1993-1995 Darren Reed"; +/*static const char rcsid[] = "@(#)$Id: ip_state.c,v 2.3.2.9 1999/10/21 14:31:09 darrenr Exp $";*/ +static const char rcsid[] = "@(#)$FreeBSD$"; +#endif + +#include <sys/errno.h> +#include <sys/types.h> +#include <sys/param.h> +#include <sys/file.h> +#if defined(__NetBSD__) && (NetBSD >= 199905) && !defined(IPFILTER_LKM) && \ + defined(_KERNEL) +# include "opt_ipfilter_log.h" +#endif +#if !defined(_KERNEL) && !defined(KERNEL) && !defined(__KERNEL__) +# include <stdio.h> +# include <stdlib.h> +# include <string.h> +#else +# ifdef linux +# include <linux/kernel.h> +# include <linux/module.h> +# endif +#endif +#if defined(KERNEL) && (__FreeBSD_version >= 220000) +# include <sys/filio.h> +# include <sys/fcntl.h> +# if (__FreeBSD_version >= 300000) && !defined(IPFILTER_LKM) +# include "opt_ipfilter.h" +# endif +#else +# include <sys/ioctl.h> +#endif +#include <sys/time.h> +#include <sys/uio.h> +#ifndef linux +# include <sys/protosw.h> +#endif +#include <sys/socket.h> +#if (defined(_KERNEL) || defined(KERNEL)) && !defined(linux) +# include <sys/systm.h> +#endif +#if !defined(__SVR4) && !defined(__svr4__) +# ifndef linux +# include <sys/mbuf.h> +# endif +#else +# include <sys/filio.h> +# include <sys/byteorder.h> +# ifdef _KERNEL +# include <sys/dditypes.h> +# endif +# 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/tcp.h> +#ifndef linux +# include <netinet/ip_var.h> +# include <netinet/tcp_fsm.h> +#endif +#include <netinet/udp.h> +#include <netinet/ip_icmp.h> +#include "netinet/ip_compat.h" +#include <netinet/tcpip.h> +#include "netinet/ip_fil.h" +#include "netinet/ip_nat.h" +#include "netinet/ip_frag.h" +#include "netinet/ip_proxy.h" +#include "netinet/ip_state.h" +#if (__FreeBSD_version >= 300000) +# include <sys/malloc.h> +# if (defined(_KERNEL) || defined(KERNEL)) && !defined(IPFILTER_LKM) +# include <sys/libkern.h> +# include <sys/systm.h> +# endif +#endif + +#ifndef MIN +# define MIN(a,b) (((a)<(b))?(a):(b)) +#endif + +#define TCP_CLOSE (TH_FIN|TH_RST) + +static ipstate_t **ips_table = NULL; +static int ips_num = 0; +static ips_stat_t ips_stats; +#if (SOLARIS || defined(__sgi)) && defined(_KERNEL) +extern KRWLOCK_T ipf_state, ipf_mutex; +extern kmutex_t ipf_rw; +#endif + +static int fr_matchsrcdst __P((ipstate_t *, struct in_addr, struct in_addr, + fr_info_t *, tcphdr_t *)); +static frentry_t *fr_checkicmpmatchingstate __P((ip_t *, fr_info_t *)); +static int fr_state_flush __P((int)); +static ips_stat_t *fr_statetstats __P((void)); +static void fr_delstate __P((ipstate_t *)); + + +#define FIVE_DAYS (2 * 5 * 86400) /* 5 days: half closed session */ + +#define TCP_MSL 240 /* 2 minutes */ +u_long fr_tcpidletimeout = FIVE_DAYS, + fr_tcpclosewait = 2 * TCP_MSL, + fr_tcplastack = 2 * TCP_MSL, + fr_tcptimeout = 2 * TCP_MSL, + fr_tcpclosed = 1, + fr_udptimeout = 240, + fr_icmptimeout = 120; +int fr_statemax = IPSTATE_MAX, + fr_statesize = IPSTATE_SIZE; +int fr_state_doflush = 0; + + +int fr_stateinit() +{ + KMALLOCS(ips_table, ipstate_t **, fr_statesize * sizeof(ipstate_t *)); + if (ips_table != NULL) + bzero((char *)ips_table, fr_statesize * sizeof(ipstate_t *)); + else + return -1; + return 0; +} + + +static ips_stat_t *fr_statetstats() +{ + ips_stats.iss_active = ips_num; + ips_stats.iss_table = ips_table; + return &ips_stats; +} + + +/* + * flush state tables. two actions currently defined: + * which == 0 : flush all state table entries + * which == 1 : flush TCP connections which have started to close but are + * stuck for some reason. + */ +static int fr_state_flush(which) +int which; +{ + register int i; + register ipstate_t *is, **isp; +#if defined(_KERNEL) && !SOLARIS + int s; +#endif + int delete, removed = 0; + + SPL_NET(s); + WRITE_ENTER(&ipf_state); + for (i = fr_statesize - 1; i >= 0; i--) + for (isp = &ips_table[i]; (is = *isp); ) { + delete = 0; + + switch (which) + { + case 0 : + delete = 1; + break; + case 1 : + if ((is->is_p == IPPROTO_TCP) && + (((is->is_state[0] <= TCPS_ESTABLISHED) && + (is->is_state[1] > TCPS_ESTABLISHED)) || + ((is->is_state[1] <= TCPS_ESTABLISHED) && + (is->is_state[0] > TCPS_ESTABLISHED)))) + delete = 1; + break; + } + + if (delete) { + *isp = is->is_next; + if (is->is_p == IPPROTO_TCP) + ips_stats.iss_fin++; + else + ips_stats.iss_expire++; + if (ips_table[i] == NULL) + ips_stats.iss_inuse--; +#ifdef IPFILTER_LOG + ipstate_log(is, ISL_FLUSH); +#endif + fr_delstate(is); + ips_num--; + removed++; + } else + isp = &is->is_next; + } + if (fr_state_doflush) { + (void) fr_state_flush(1); + fr_state_doflush = 0; + } + RWLOCK_EXIT(&ipf_state); + SPL_X(s); + return removed; +} + + +int fr_state_ioctl(data, cmd, mode) +caddr_t data; +#if defined(__NetBSD__) || defined(__OpenBSD__) +u_long cmd; +#else +int cmd; +#endif +int mode; +{ + int arg, ret, error = 0; + + switch (cmd) + { + case SIOCIPFFL : + IRCOPY(data, (caddr_t)&arg, sizeof(arg)); + if (arg == 0 || arg == 1) { + ret = fr_state_flush(arg); + IWCOPY((caddr_t)&ret, data, sizeof(ret)); + } else + error = EINVAL; + break; + case SIOCGIPST : + IWCOPY((caddr_t)fr_statetstats(), data, sizeof(ips_stat_t)); + break; + case FIONREAD : +#ifdef IPFILTER_LOG + IWCOPY((caddr_t)&iplused[IPL_LOGSTATE], (caddr_t)data, + sizeof(iplused[IPL_LOGSTATE])); +#endif + break; + default : + error = EINVAL; + break; + } + return error; +} + + +/* + * Create a new ipstate structure and hang it off the hash table. + */ +ipstate_t *fr_addstate(ip, fin, flags) +ip_t *ip; +fr_info_t *fin; +u_int flags; +{ + register ipstate_t *is; + register u_int hv; + ipstate_t ips; + u_int pass; + + if ((ip->ip_off & IP_OFFMASK) || (fin->fin_fi.fi_fl & FI_SHORT)) + return NULL; + if (ips_num == fr_statemax) { + ips_stats.iss_max++; + fr_state_doflush = 1; + return NULL; + } + is = &ips; + bzero((char *)is, sizeof(*is)); + ips.is_age = 1; + ips.is_state[0] = 0; + ips.is_state[1] = 0; + /* + * Copy and calculate... + */ + hv = (is->is_p = ip->ip_p); + hv += (is->is_src.s_addr = ip->ip_src.s_addr); + hv += (is->is_dst.s_addr = ip->ip_dst.s_addr); + + switch (ip->ip_p) + { + case IPPROTO_ICMP : + { + struct icmp *ic = (struct icmp *)fin->fin_dp; + + switch (ic->icmp_type) + { + case ICMP_ECHO : + is->is_icmp.ics_type = ICMP_ECHOREPLY; /* XXX */ + hv += (is->is_icmp.ics_id = ic->icmp_id); + hv += (is->is_icmp.ics_seq = ic->icmp_seq); + break; + case ICMP_TSTAMP : + case ICMP_IREQ : + case ICMP_MASKREQ : + is->is_icmp.ics_type = ic->icmp_type + 1; + break; + default : + return NULL; + } + ATOMIC_INC(ips_stats.iss_icmp); + is->is_age = fr_icmptimeout; + break; + } + case IPPROTO_TCP : + { + register tcphdr_t *tcp = (tcphdr_t *)fin->fin_dp; + + /* + * The endian of the ports doesn't matter, but the ack and + * sequence numbers do as we do mathematics on them later. + */ + is->is_dport = tcp->th_dport; + is->is_sport = tcp->th_sport; + if ((flags & (FI_W_DPORT|FI_W_SPORT)) == 0) { + hv += tcp->th_dport; + hv += tcp->th_sport; + } + if (tcp->th_seq != 0) { + is->is_send = ntohl(tcp->th_seq) + ip->ip_len - + fin->fin_hlen - (tcp->th_off << 2) + + ((tcp->th_flags & TH_SYN) ? 1 : 0) + + ((tcp->th_flags & TH_FIN) ? 1 : 0); + is->is_maxsend = is->is_send + 1; + } + is->is_dend = 0; + is->is_maxswin = ntohs(tcp->th_win); + if (is->is_maxswin == 0) + is->is_maxswin = 1; + /* + * If we're creating state for a starting connection, start the + * timer on it as we'll never see an error if it fails to + * connect. + */ + MUTEX_ENTER(&ipf_rw); + ips_stats.iss_tcp++; + fr_tcp_age(&is->is_age, is->is_state, ip, fin, + tcp->th_sport == is->is_sport); + MUTEX_EXIT(&ipf_rw); + break; + } + case IPPROTO_UDP : + { + register tcphdr_t *tcp = (tcphdr_t *)fin->fin_dp; + + if ((flags & (FI_W_DPORT|FI_W_SPORT)) == 0) { + hv += (is->is_dport = tcp->th_dport); + hv += (is->is_sport = tcp->th_sport); + } + ATOMIC_INC(ips_stats.iss_udp); + is->is_age = fr_udptimeout; + break; + } + default : + return NULL; + } + + KMALLOC(is, ipstate_t *); + if (is == NULL) { + ATOMIC_INC(ips_stats.iss_nomem); + return NULL; + } + bcopy((char *)&ips, (char *)is, sizeof(*is)); + hv %= fr_statesize; + RW_UPGRADE(&ipf_mutex); + is->is_rule = fin->fin_fr; + if (is->is_rule != NULL) { + is->is_rule->fr_ref++; + pass = is->is_rule->fr_flags; + } else + pass = fr_flags; + MUTEX_DOWNGRADE(&ipf_mutex); + WRITE_ENTER(&ipf_state); + + is->is_rout = pass & FR_OUTQUE ? 1 : 0; + is->is_pass = pass; + is->is_pkts = 1; + is->is_bytes = ip->ip_len; + /* + * We want to check everything that is a property of this packet, + * but we don't (automatically) care about it's fragment status as + * this may change. + */ + is->is_opt = fin->fin_fi.fi_optmsk; + is->is_optmsk = 0xffffffff; + is->is_sec = fin->fin_fi.fi_secmsk; + is->is_secmsk = 0xffff; + is->is_auth = fin->fin_fi.fi_auth; + is->is_authmsk = 0xffff; + is->is_flags = fin->fin_fi.fi_fl & FI_CMP; + is->is_flags |= FI_CMP << 4; + is->is_flags |= flags & (FI_W_DPORT|FI_W_SPORT); + /* + * add into table. + */ + is->is_next = ips_table[hv]; + ips_table[hv] = is; + if (is->is_next == NULL) + ips_stats.iss_inuse++; + if (fin->fin_out) { + is->is_ifpin = NULL; + is->is_ifpout = fin->fin_ifp; + } else { + is->is_ifpin = fin->fin_ifp; + is->is_ifpout = NULL; + } + if (pass & FR_LOGFIRST) + is->is_pass &= ~(FR_LOGFIRST|FR_LOG); + ATOMIC_INC(ips_num); +#ifdef IPFILTER_LOG + ipstate_log(is, ISL_NEW); +#endif + RWLOCK_EXIT(&ipf_state); + fin->fin_rev = (is->is_dst.s_addr != ip->ip_dst.s_addr); + if (fin->fin_fi.fi_fl & FI_FRAG) + ipfr_newfrag(ip, fin, pass ^ FR_KEEPSTATE); + return is; +} + + + +/* + * check to see if a packet with TCP headers fits within the TCP window. + * change timeout depending on whether new packet is a SYN-ACK returning for a + * SYN or a RST or FIN which indicate time to close up shop. + */ +int fr_tcpstate(is, fin, ip, tcp) +register ipstate_t *is; +fr_info_t *fin; +ip_t *ip; +tcphdr_t *tcp; +{ + register tcp_seq seq, ack, end; + register int ackskew; + tcpdata_t *fdata, *tdata; + u_short win, maxwin; + int ret = 0; + int source; + + /* + * Find difference between last checked packet and this packet. + */ + source = (ip->ip_src.s_addr == is->is_src.s_addr); + fdata = &is->is_tcp.ts_data[!source]; + tdata = &is->is_tcp.ts_data[source]; + seq = ntohl(tcp->th_seq); + ack = ntohl(tcp->th_ack); + win = ntohs(tcp->th_win); + end = seq + ip->ip_len - fin->fin_hlen - (tcp->th_off << 2) + + ((tcp->th_flags & TH_SYN) ? 1 : 0) + + ((tcp->th_flags & TH_FIN) ? 1 : 0); + + if (fdata->td_end == 0) { + /* + * Must be a (outgoing) SYN-ACK in reply to a SYN. + */ + fdata->td_end = end; + fdata->td_maxwin = 1; + fdata->td_maxend = end + 1; + } + + if (!(tcp->th_flags & TH_ACK)) { /* Pretend an ack was sent */ + ack = tdata->td_end; + win = 1; + } else if (((tcp->th_flags & (TH_ACK|TH_RST)) == (TH_ACK|TH_RST)) && + (ack == 0)) { + /* gross hack to get around certain broken tcp stacks */ + ack = tdata->td_end; + } + + if (seq == end) + seq = end = fdata->td_end; + + maxwin = tdata->td_maxwin; + ackskew = tdata->td_end - ack; + +#define SEQ_GE(a,b) ((int)((a) - (b)) >= 0) +#define SEQ_GT(a,b) ((int)((a) - (b)) > 0) + if ((SEQ_GE(fdata->td_maxend, end)) && + (SEQ_GE(seq + maxwin, fdata->td_end - maxwin)) && +/* XXX what about big packets */ +#define MAXACKWINDOW 66000 + (ackskew >= -MAXACKWINDOW) && + (ackskew <= MAXACKWINDOW)) { + /* if ackskew < 0 then this should be due to fragented + * packets. There is no way to know the length of the + * total packet in advance. + * We do know the total length from the fragment cache though. + * Note however that there might be more sessions with + * exactly the same source and destination paramters in the + * state cache (and source and destination is the only stuff + * that is saved in the fragment cache). Note further that + * some TCP connections in the state cache are hashed with + * sport and dport as well which makes it not worthwhile to + * look for them. + * Thus, when ackskew is negative but still seems to belong + * to this session, we bump up the destinations end value. + */ + if (ackskew < 0) + tdata->td_end = ack; + + /* update max window seen */ + if (fdata->td_maxwin < win) + fdata->td_maxwin = win; + if (SEQ_GT(end, fdata->td_end)) + fdata->td_end = end; + if (SEQ_GE(ack + win, tdata->td_maxend)) { + tdata->td_maxend = ack + win; + if (win == 0) + tdata->td_maxend++; + } + + ATOMIC_INC(ips_stats.iss_hits); + is->is_pkts++; + is->is_bytes += ip->ip_len; + /* + * Nearing end of connection, start timeout. + */ + MUTEX_ENTER(&ipf_rw); + fr_tcp_age(&is->is_age, is->is_state, ip, fin, source); + MUTEX_EXIT(&ipf_rw); + ret = 1; + } + return ret; +} + + +static int fr_matchsrcdst(is, src, dst, fin, tcp) +ipstate_t *is; +struct in_addr src, dst; +fr_info_t *fin; +tcphdr_t *tcp; +{ + int ret = 0, rev, out, flags; + u_short sp, dp; + void *ifp; + + rev = fin->fin_rev = (is->is_dst.s_addr != dst.s_addr); + ifp = fin->fin_ifp; + out = fin->fin_out; + + if (tcp != NULL) { + flags = is->is_flags; + sp = tcp->th_sport; + dp = tcp->th_dport; + } else { + flags = 0; + sp = 0; + dp = 0; + } + + if (rev == 0) { + if (!out) { + if (is->is_ifpin == ifp) + ret = 1; + } else { + if (is->is_ifpout == NULL || is->is_ifpout == ifp) + ret = 1; + } + } else { + if (out) { + if (is->is_ifpin == ifp) + ret = 1; + } else { + if (is->is_ifpout == NULL || is->is_ifpout == ifp) + ret = 1; + } + } + if (ret == 0) + return 0; + ret = 0; + + if (rev == 0) { + if ((is->is_dst.s_addr == dst.s_addr) && + (is->is_src.s_addr == src.s_addr) && + (!tcp || ((sp == is->is_sport || flags & FI_W_SPORT) && + (dp == is->is_dport || flags & FI_W_DPORT)))) { + ret = 1; + } + } else { + if ((is->is_dst.s_addr == src.s_addr) && + (is->is_src.s_addr == dst.s_addr) && + (!tcp || ((sp == is->is_dport || flags & FI_W_DPORT) && + (dp == is->is_sport || flags & FI_W_SPORT)))) { + ret = 1; + } + } + if (ret == 0) + return 0; + + /* + * Whether or not this should be here, is questionable, but the aim + * is to get this out of the main line. + */ + if (tcp == NULL) + flags = is->is_flags & (FI_CMP|(FI_CMP<<4)); + + if (((fin->fin_fi.fi_fl & (flags >> 4)) != (flags & FI_CMP)) || + ((fin->fin_fi.fi_optmsk & is->is_optmsk) != is->is_opt) || + ((fin->fin_fi.fi_secmsk & is->is_secmsk) != is->is_sec) || + ((fin->fin_fi.fi_auth & is->is_authmsk) != is->is_auth)) + return 0; + + if ((flags & (FI_W_SPORT|FI_W_DPORT))) { + if ((flags & FI_W_SPORT) != 0) { + if (rev == 0) { + is->is_sport = sp; + is->is_send = htonl(tcp->th_seq); + } else { + is->is_sport = dp; + is->is_send = htonl(tcp->th_ack); + } + is->is_maxsend = is->is_send + 1; + } else if ((flags & FI_W_DPORT) != 0) { + if (rev == 0) { + is->is_dport = dp; + is->is_dend = htonl(tcp->th_ack); + } else { + is->is_dport = sp; + is->is_dend = htonl(tcp->th_seq); + } + is->is_maxdend = is->is_dend + 1; + } + is->is_flags &= ~(FI_W_SPORT|FI_W_DPORT); + } + + if (!rev) { + if (out && (out == is->is_rout)) { + if (!is->is_ifpout) + is->is_ifpout = ifp; + } else { + if (!is->is_ifpin) + is->is_ifpin = ifp; + } + } else { + if (!out && (out != is->is_rout)) { + if (!is->is_ifpin) + is->is_ifpin = ifp; + } else { + if (!is->is_ifpout) + is->is_ifpout = ifp; + } + } + return 1; +} + +frentry_t *fr_checkicmpmatchingstate(ip, fin) +ip_t *ip; +fr_info_t *fin; +{ + register struct in_addr dst, src; + register ipstate_t *is, **isp; + register u_short sport, dport; + register u_char pr; + struct icmp *ic; + fr_info_t ofin; + u_int hv, dest; + tcphdr_t *tcp; + frentry_t *fr; + ip_t *oip; + int type; + + /* + * Does it at least have the return (basic) IP header ? + * Only a basic IP header (no options) should be with + * an ICMP error header. + */ + if ((ip->ip_hl != 5) || (ip->ip_len < ICMPERR_MINPKTLEN)) + return NULL; + ic = (struct icmp *)((char *)ip + fin->fin_hlen); + type = ic->icmp_type; + /* + * If it's not an error type, then return + */ + if ((type != ICMP_UNREACH) && (type != ICMP_SOURCEQUENCH) && + (type != ICMP_REDIRECT) && (type != ICMP_TIMXCEED) && + (type != ICMP_PARAMPROB)) + return NULL; + + oip = (ip_t *)((char *)fin->fin_dp + ICMPERR_ICMPHLEN); + if (ip->ip_len < ICMPERR_MAXPKTLEN + ((oip->ip_hl - 5) << 2)) + return NULL; + if ((oip->ip_p != IPPROTO_TCP) && (oip->ip_p != IPPROTO_UDP)) + return NULL; + + tcp = (tcphdr_t *)((char *)oip + (oip->ip_hl << 2)); + dport = tcp->th_dport; + sport = tcp->th_sport; + + hv = (pr = oip->ip_p); + hv += (src.s_addr = oip->ip_src.s_addr); + hv += (dst.s_addr = oip->ip_dst.s_addr); + hv += dport; + hv += sport; + hv %= fr_statesize; + /* + * we make an fin entry to be able to feed it to + * matchsrcdst note that not all fields are encessary + * but this is the cleanest way. Note further we fill + * in fin_mp such that if someone uses it we'll get + * a kernel panic. fr_matchsrcdst does not use this. + * + * watch out here, as ip is in host order and oip in network + * order. Any change we make must be undone afterwards. + */ + oip->ip_len = ntohs(oip->ip_len); + fr_makefrip(oip->ip_hl << 2, oip, &ofin); + oip->ip_len = htons(oip->ip_len); + ofin.fin_ifp = fin->fin_ifp; + ofin.fin_out = !fin->fin_out; + ofin.fin_mp = NULL; /* if dereferenced, panic XXX */ + READ_ENTER(&ipf_state); + for (isp = &ips_table[hv]; (is = *isp); isp = &is->is_next) { + /* + * Only allow this icmp though if the + * encapsulated packet was allowed through the + * other way around. Note that the minimal amount + * of info present does not allow for checking against + * tcp internals such as seq and ack numbers. + */ + if ((is->is_p == pr) && + fr_matchsrcdst(is, src, dst, &ofin, tcp)) { + fr = is->is_rule; + ips_stats.iss_hits++; + /* + * we must swap src and dst here because the icmp + * comes the other way around + */ + dest = (is->is_dst.s_addr != src.s_addr); + is->is_pkts++; + is->is_bytes += ip->ip_len; + /* + * we deliberately do not touch the timeouts + * for the accompanying state table entry. + * It remains to be seen if that is correct. XXX + */ + RWLOCK_EXIT(&ipf_state); + return fr; + } + } + RWLOCK_EXIT(&ipf_state); + return NULL; +} + +/* + * Check if a packet has a registered state. + */ +frentry_t *fr_checkstate(ip, fin) +ip_t *ip; +fr_info_t *fin; +{ + register struct in_addr dst, src; + register ipstate_t *is, **isp; + register u_char pr; + u_int hv, hvm, hlen, tryagain, pass; + struct icmp *ic; + frentry_t *fr; + tcphdr_t *tcp; + + if ((ip->ip_off & IP_OFFMASK) || (fin->fin_fi.fi_fl & FI_SHORT)) + return NULL; + + is = NULL; + hlen = fin->fin_hlen; + tcp = (tcphdr_t *)((char *)ip + hlen); + ic = (struct icmp *)tcp; + hv = (pr = ip->ip_p); + hv += (src.s_addr = ip->ip_src.s_addr); + hv += (dst.s_addr = ip->ip_dst.s_addr); + + /* + * Search the hash table for matching packet header info. + */ + switch (ip->ip_p) + { + case IPPROTO_ICMP : + hv += ic->icmp_id; + hv += ic->icmp_seq; + hv %= fr_statesize; + READ_ENTER(&ipf_state); + for (isp = &ips_table[hv]; (is = *isp); isp = &is->is_next) + if ((is->is_p == pr) && + (ic->icmp_id == is->is_icmp.ics_id) && + (ic->icmp_seq == is->is_icmp.ics_seq) && + fr_matchsrcdst(is, src, dst, fin, NULL)) { + if ((is->is_type == ICMP_ECHOREPLY) && + (ic->icmp_type == ICMP_ECHO)) + ; + else if (is->is_type != ic->icmp_type) + continue; + is->is_age = fr_icmptimeout; + break; + } + if (is != NULL) + break; + RWLOCK_EXIT(&ipf_state); + /* + * No matching icmp state entry. Perhaps this is a + * response to another state entry. + */ + fr = fr_checkicmpmatchingstate(ip, fin); + if (fr) + return fr; + break; + case IPPROTO_TCP : + { + register u_short dport = tcp->th_dport, sport = tcp->th_sport; + + tryagain = 0; +retry_tcp: + hvm = hv % fr_statesize; + WRITE_ENTER(&ipf_state); + for (isp = &ips_table[hvm]; (is = *isp); + isp = &is->is_next) + if ((is->is_p == pr) && + fr_matchsrcdst(is, src, dst, fin, tcp)) { + if (fr_tcpstate(is, fin, ip, tcp)) { + break; +#ifndef _KERNEL + if (tcp->th_flags & TCP_CLOSE) { + *isp = is->is_next; + isp = &ips_table[hvm]; + if (ips_table[hvm] == NULL) + ips_stats.iss_inuse--; + fr_delstate(is); + ips_num--; + } +#endif + break; + } + is = NULL; + break; + } + if (is != NULL) + break; + RWLOCK_EXIT(&ipf_state); + hv += dport; + hv += sport; + if (tryagain == 0) { + tryagain = 1; + goto retry_tcp; + } + break; + } + case IPPROTO_UDP : + { + register u_short dport = tcp->th_dport, sport = tcp->th_sport; + + tryagain = 0; +retry_udp: + hvm = hv % fr_statesize; + /* + * Nothing else to match on but ports. and IP#'s + */ + READ_ENTER(&ipf_state); + for (is = ips_table[hvm]; is; is = is->is_next) + if ((is->is_p == pr) && + fr_matchsrcdst(is, src, dst, fin, tcp)) { + is->is_age = fr_udptimeout; + break; + } + if (is != NULL) + break; + RWLOCK_EXIT(&ipf_state); + hv += dport; + hv += sport; + if (tryagain == 0) { + tryagain = 1; + goto retry_udp; + } + break; + } + default : + break; + } + if (is == NULL) { + ATOMIC_INC(ips_stats.iss_miss); + return NULL; + } + MUTEX_ENTER(&ipf_rw); + is->is_bytes += ip->ip_len; + ips_stats.iss_hits++; + is->is_pkts++; + MUTEX_EXIT(&ipf_rw); + fr = is->is_rule; + fin->fin_fr = fr; + pass = is->is_pass; + RWLOCK_EXIT(&ipf_state); + if (fin->fin_fi.fi_fl & FI_FRAG) + ipfr_newfrag(ip, fin, pass ^ FR_KEEPSTATE); + return fr; +} + + +static void fr_delstate(is) +ipstate_t *is; +{ + frentry_t *fr; + + fr = is->is_rule; + if (fr != NULL) { + ATOMIC_DEC(fr->fr_ref); + if (fr->fr_ref == 0) + KFREE(fr); + } + KFREE(is); +} + + +/* + * Free memory in use by all state info. kept. + */ +void fr_stateunload() +{ + register int i; + register ipstate_t *is, **isp; + + WRITE_ENTER(&ipf_state); + for (i = fr_statesize - 1; i >= 0; i--) + for (isp = &ips_table[i]; (is = *isp); ) { + *isp = is->is_next; + fr_delstate(is); + ips_num--; + } + ips_stats.iss_inuse = 0; + ips_num = 0; + RWLOCK_EXIT(&ipf_state); + KFREES(ips_table, fr_statesize * sizeof(ipstate_t *)); + ips_table = NULL; +} + + +/* + * Slowly expire held state for thingslike UDP and ICMP. Timeouts are set + * in expectation of this being called twice per second. + */ +void fr_timeoutstate() +{ + register int i; + register ipstate_t *is, **isp; +#if defined(_KERNEL) && !SOLARIS + int s; +#endif + + SPL_NET(s); + WRITE_ENTER(&ipf_state); + for (i = fr_statesize - 1; i >= 0; i--) + for (isp = &ips_table[i]; (is = *isp); ) + if (is->is_age && !--is->is_age) { + *isp = is->is_next; + if (is->is_p == IPPROTO_TCP) + ips_stats.iss_fin++; + else + ips_stats.iss_expire++; + if (ips_table[i] == NULL) + ips_stats.iss_inuse--; +#ifdef IPFILTER_LOG + ipstate_log(is, ISL_EXPIRE); +#endif + fr_delstate(is); + ips_num--; + } else + isp = &is->is_next; + RWLOCK_EXIT(&ipf_state); + SPL_X(s); +} + + +/* + * Original idea freom Pradeep Krishnan for use primarily with NAT code. + * (pkrishna@netcom.com) + */ +void fr_tcp_age(age, state, ip, fin, dir) +u_long *age; +u_char *state; +ip_t *ip; +fr_info_t *fin; +int dir; +{ + tcphdr_t *tcp = (tcphdr_t *)fin->fin_dp; + u_char flags = tcp->th_flags; + int dlen, ostate; + + ostate = state[1 - dir]; + + dlen = ip->ip_len - fin->fin_hlen - (tcp->th_off << 2); + + if (flags & TH_RST) { + if (!(tcp->th_flags & TH_PUSH) && !dlen) { + *age = fr_tcpclosed; + state[dir] = TCPS_CLOSED; + } else { + *age = fr_tcpclosewait; + state[dir] = TCPS_CLOSE_WAIT; + } + return; + } + + *age = fr_tcptimeout; /* 1 min */ + + switch(state[dir]) + { + case TCPS_CLOSED: + if ((flags & (TH_FIN|TH_SYN|TH_RST|TH_ACK)) == TH_ACK) { + state[dir] = TCPS_ESTABLISHED; + *age = fr_tcpidletimeout; + } + case TCPS_FIN_WAIT_2: + if ((flags & TH_OPENING) == TH_OPENING) + state[dir] = TCPS_SYN_RECEIVED; + else if (flags & TH_SYN) + state[dir] = TCPS_SYN_SENT; + break; + case TCPS_SYN_RECEIVED: + case TCPS_SYN_SENT: + if ((flags & (TH_FIN|TH_ACK)) == TH_ACK) { + state[dir] = TCPS_ESTABLISHED; + *age = fr_tcpidletimeout; + } else if ((flags & (TH_FIN|TH_ACK)) == (TH_FIN|TH_ACK)) { + state[dir] = TCPS_CLOSE_WAIT; + if (!(flags & TH_PUSH) && !dlen && + ostate > TCPS_ESTABLISHED) + *age = fr_tcplastack; + else + *age = fr_tcpclosewait; + } + break; + case TCPS_ESTABLISHED: + if (flags & TH_FIN) { + state[dir] = TCPS_CLOSE_WAIT; + if (!(flags & TH_PUSH) && !dlen && + ostate > TCPS_ESTABLISHED) + *age = fr_tcplastack; + else + *age = fr_tcpclosewait; + } else { + if (ostate < TCPS_CLOSE_WAIT) + *age = fr_tcpidletimeout; + } + break; + case TCPS_CLOSE_WAIT: + if ((flags & TH_FIN) && !(flags & TH_PUSH) && !dlen && + ostate > TCPS_ESTABLISHED) { + *age = fr_tcplastack; + state[dir] = TCPS_LAST_ACK; + } else + *age = fr_tcpclosewait; + break; + case TCPS_LAST_ACK: + if (flags & TH_ACK) { + state[dir] = TCPS_FIN_WAIT_2; + if (!(flags & TH_PUSH) && !dlen && + ostate > TCPS_ESTABLISHED) + *age = fr_tcplastack; + else { + *age = fr_tcpclosewait; + state[dir] = TCPS_CLOSE_WAIT; + } + } + break; + } +} + + +#ifdef IPFILTER_LOG +void ipstate_log(is, type) +struct ipstate *is; +u_int type; +{ + struct ipslog ipsl; + void *items[1]; + size_t sizes[1]; + int types[1]; + + ipsl.isl_type = type; + ipsl.isl_pkts = is->is_pkts; + ipsl.isl_bytes = is->is_bytes; + ipsl.isl_src = is->is_src; + ipsl.isl_dst = is->is_dst; + ipsl.isl_p = is->is_p; + ipsl.isl_flags = is->is_flags; + if (ipsl.isl_p == IPPROTO_TCP || ipsl.isl_p == IPPROTO_UDP) { + ipsl.isl_sport = is->is_sport; + ipsl.isl_dport = is->is_dport; + if (ipsl.isl_p == IPPROTO_TCP) { + ipsl.isl_state[0] = is->is_state[0]; + ipsl.isl_state[1] = is->is_state[1]; + } + } else if (ipsl.isl_p == IPPROTO_ICMP) + ipsl.isl_itype = is->is_icmp.ics_type; + else { + ipsl.isl_ps.isl_filler[0] = 0; + ipsl.isl_ps.isl_filler[1] = 0; + } + items[0] = &ipsl; + sizes[0] = sizeof(ipsl); + types[0] = 0; + + (void) ipllog(IPL_LOGSTATE, NULL, items, sizes, types, 1); +} +#endif |
