diff options
Diffstat (limited to 'sys/netinet/ip_state.c')
| -rw-r--r-- | sys/netinet/ip_state.c | 1901 |
1 files changed, 1901 insertions, 0 deletions
diff --git a/sys/netinet/ip_state.c b/sys/netinet/ip_state.c new file mode 100644 index 0000000..8cfe62d --- /dev/null +++ b/sys/netinet/ip_state.c @@ -0,0 +1,1901 @@ +/* + * Copyright (C) 1995-2000 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[] = "@(#)$FreeBSD$"; +#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(__FreeBSD_version) && \ + (__FreeBSD_version >= 400000) && !defined(KLD_MODULE) +#include "opt_inet6.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) || 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" +#ifdef USE_INET6 +#include <netinet/icmp6.h> +#endif +#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 ipstate_t *ips_list = NULL; +static int ips_num = 0; +static int ips_wild = 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 + +#ifdef USE_INET6 +static frentry_t *fr_checkicmp6matchingstate __P((ip6_t *, fr_info_t *)); +#endif +static int fr_matchsrcdst __P((ipstate_t *, union i6addr, union i6addr, + fr_info_t *, tcphdr_t *)); +static frentry_t *fr_checkicmpmatchingstate __P((ip_t *, fr_info_t *)); +static int fr_matchicmpqueryreply __P((int, ipstate_t *, icmphdr_t *)); +static int fr_state_flush __P((int)); +static ips_stat_t *fr_statetstats __P((void)); +static void fr_delstate __P((ipstate_t *)); +static int fr_state_remove __P((caddr_t)); +static void fr_ipsmove __P((ipstate_t **, ipstate_t *, u_int)); +int fr_stputent __P((caddr_t)); +int fr_stgetent __P((caddr_t)); +void fr_stinsert __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 = 120, + fr_tcphalfclosed = 2 * 2 * 3600, /* 2 hours */ + fr_udptimeout = 240, + fr_icmptimeout = 120; +int fr_statemax = IPSTATE_MAX, + fr_statesize = IPSTATE_SIZE; +int fr_state_doflush = 0, + fr_state_lock = 0; + +static int icmpreplytype4[ICMP_MAXTYPE + 1]; + +int fr_stateinit() +{ + int i; + + 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; + + /* fill icmp reply type table */ + for (i = 0; i <= ICMP_MAXTYPE; i++) + icmpreplytype4[i] = -1; + icmpreplytype4[ICMP_ECHO] = ICMP_ECHOREPLY; + icmpreplytype4[ICMP_TSTAMP] = ICMP_TSTAMPREPLY; + icmpreplytype4[ICMP_IREQ] = ICMP_IREQREPLY; + icmpreplytype4[ICMP_MASKREQ] = ICMP_MASKREPLY; + + return 0; +} + + +static ips_stat_t *fr_statetstats() +{ + ips_stats.iss_active = ips_num; + ips_stats.iss_table = ips_table; + ips_stats.iss_list = ips_list; + 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 ipstate_t *is, **isp; +#if defined(_KERNEL) && !SOLARIS + int s; +#endif + int delete, removed = 0; + + SPL_NET(s); + for (isp = &ips_list; (is = *isp); ) { + delete = 0; + + switch (which) + { + case 0 : + delete = 1; + break; + case 1 : + if (is->is_p != IPPROTO_TCP) + break; + if ((is->is_state[0] != TCPS_ESTABLISHED) || + (is->is_state[1] != TCPS_ESTABLISHED)) + delete = 1; + break; + } + + if (delete) { + if (is->is_p == IPPROTO_TCP) + ips_stats.iss_fin++; + else + ips_stats.iss_expire++; +#ifdef IPFILTER_LOG + ipstate_log(is, ISL_FLUSH); +#endif + fr_delstate(is); + removed++; + } else + isp = &is->is_next; + } + SPL_X(s); + return removed; +} + + +static int fr_state_remove(data) +caddr_t data; +{ + ipstate_t *sp, st; + int error; + + sp = &st; + error = IRCOPYPTR(data, (caddr_t)&st, sizeof(st)); + if (error) + return EFAULT; + + for (sp = ips_list; sp; sp = sp->is_next) + if ((sp->is_p == st.is_p) && (sp->is_v == st.is_v) && + !bcmp((char *)&sp->is_src, (char *)&st.is_src, + sizeof(st.is_src)) && + !bcmp((char *)&sp->is_dst, (char *)&st.is_src, + sizeof(st.is_dst)) && + !bcmp((char *)&sp->is_ps, (char *)&st.is_ps, + sizeof(st.is_ps))) { + WRITE_ENTER(&ipf_state); +#ifdef IPFILTER_LOG + ipstate_log(sp, ISL_REMOVE); +#endif + fr_delstate(sp); + RWLOCK_EXIT(&ipf_state); + return 0; + } + return ESRCH; +} + + +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 SIOCDELST : + error = fr_state_remove(data); + break; + case SIOCIPFFL : + error = IRCOPY(data, (caddr_t)&arg, sizeof(arg)); + if (error) + break; + if (arg == 0 || arg == 1) { + WRITE_ENTER(&ipf_state); + ret = fr_state_flush(arg); + RWLOCK_EXIT(&ipf_state); + error = IWCOPY((caddr_t)&ret, data, sizeof(ret)); + } else + error = EINVAL; + break; +#ifdef IPFILTER_LOG + case SIOCIPFFB : + if (!(mode & FWRITE)) + error = EPERM; + else { + int tmp; + + tmp = ipflog_clear(IPL_LOGSTATE); + IWCOPY((char *)&tmp, data, sizeof(tmp)); + } + break; +#endif + case SIOCGETFS : + error = IWCOPYPTR((caddr_t)fr_statetstats(), data, + sizeof(ips_stat_t)); + break; + case FIONREAD : +#ifdef IPFILTER_LOG + arg = (int)iplused[IPL_LOGSTATE]; + error = IWCOPY((caddr_t)&arg, (caddr_t)data, sizeof(arg)); +#endif + break; + case SIOCSTLCK : + error = fr_lock(data, &fr_state_lock); + break; + case SIOCSTPUT : + if (!fr_state_lock) { + error = EACCES; + break; + } + error = fr_stputent(data); + break; + case SIOCSTGET : + if (!fr_state_lock) { + error = EACCES; + break; + } + error = fr_stgetent(data); + break; + default : + error = EINVAL; + break; + } + return error; +} + + +int fr_stgetent(data) +caddr_t data; +{ + register ipstate_t *is, *isn; + ipstate_save_t ips, *ipsp; + int error; + + error = IRCOPY(data, (caddr_t)&ipsp, sizeof(ipsp)); + if (error) + return EFAULT; + error = IRCOPY((caddr_t)ipsp, (caddr_t)&ips, sizeof(ips)); + if (error) + return EFAULT; + + isn = ips.ips_next; + if (!isn) { + isn = ips_list; + if (isn == NULL) { + if (ips.ips_next == NULL) + return ENOENT; + return 0; + } + } else { + /* + * Make sure the pointer we're copying from exists in the + * current list of entries. Security precaution to prevent + * copying of random kernel data. + */ + for (is = ips_list; is; is = is->is_next) + if (is == isn) + break; + if (!is) + return ESRCH; + } + ips.ips_next = isn->is_next; + bcopy((char *)isn, (char *)&ips.ips_is, sizeof(ips.ips_is)); + if (isn->is_rule) + bcopy((char *)isn->is_rule, (char *)&ips.ips_fr, + sizeof(ips.ips_fr)); + error = IWCOPY((caddr_t)&ips, ipsp, sizeof(ips)); + if (error) + error = EFAULT; + return error; +} + + +int fr_stputent(data) +caddr_t data; +{ + register ipstate_t *is, *isn; + ipstate_save_t ips, *ipsp; + int error, out; + frentry_t *fr; + + error = IRCOPY(data, (caddr_t)&ipsp, sizeof(ipsp)); + if (error) + return EFAULT; + error = IRCOPY((caddr_t)ipsp, (caddr_t)&ips, sizeof(ips)); + if (error) + return EFAULT; + + KMALLOC(isn, ipstate_t *); + if (isn == NULL) + return ENOMEM; + + bcopy((char *)&ips.ips_is, (char *)isn, sizeof(*isn)); + fr = isn->is_rule; + if (fr != NULL) { + if (isn->is_flags & FI_NEWFR) { + KMALLOC(fr, frentry_t *); + if (fr == NULL) { + KFREE(isn); + return ENOMEM; + } + bcopy((char *)&ips.ips_fr, (char *)fr, sizeof(*fr)); + out = fr->fr_flags & FR_OUTQUE ? 1 : 0; + isn->is_rule = fr; + ips.ips_is.is_rule = fr; + if (*fr->fr_ifname) { + fr->fr_ifa = GETUNIT(fr->fr_ifname, fr->fr_v); + if (fr->fr_ifa == NULL) + fr->fr_ifa = (void *)-1; +#ifdef _KERNEL + else { + strncpy(isn->is_ifname[out], + IFNAME(fr->fr_ifa), IFNAMSIZ); + isn->is_ifp[out] = fr->fr_ifa; + } +#endif + } else + fr->fr_ifa = NULL; + /* + * send a copy back to userland of what we ended up + * to allow for verification. + */ + error = IWCOPY((caddr_t)&ips, ipsp, sizeof(ips)); + if (error) { + KFREE(isn); + KFREE(fr); + return EFAULT; + } + } else { + for (is = ips_list; is; is = is->is_next) + if (is->is_rule == fr) + break; + if (!is) { + KFREE(isn); + return ESRCH; + } + } + } + fr_stinsert(isn); + return 0; +} + + +void fr_stinsert(is) +register ipstate_t *is; +{ + register u_int hv = is->is_hv; + + MUTEX_INIT(&is->is_lock, "ipf state entry", NULL); + + is->is_ifname[0][sizeof(is->is_ifname[0]) - 1] = '\0'; + if (is->is_ifname[0][0] != '\0') { + is->is_ifp[0] = GETUNIT(is->is_ifname[0], is->is_v); + } + is->is_ifname[1][sizeof(is->is_ifname[0]) - 1] = '\0'; + if (is->is_ifname[1][0] != '\0') { + is->is_ifp[1] = GETUNIT(is->is_ifname[1], is->is_v); + } + + /* + * add into list table. + */ + if (ips_list) + ips_list->is_pnext = &is->is_next; + is->is_pnext = &ips_list; + is->is_next = ips_list; + ips_list = is; + if (ips_table[hv]) + ips_table[hv]->is_phnext = &is->is_hnext; + else + ips_stats.iss_inuse++; + is->is_phnext = ips_table + hv; + is->is_hnext = ips_table[hv]; + ips_table[hv] = is; + ips_num++; +} + + +/* + * 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 tcphdr_t *tcp = NULL; + register ipstate_t *is; + register u_int hv; + ipstate_t ips; + u_int pass; + int out; + + if (fr_state_lock || (fin->fin_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; + } + out = fin->fin_out; + 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 = fin->fin_fi.fi_p); + is->is_src = fin->fin_fi.fi_src; + hv += is->is_saddr; + is->is_dst = fin->fin_fi.fi_dst; + hv += is->is_daddr; +#ifdef USE_INET6 + if (fin->fin_v == 6) { + if (is->is_p == IPPROTO_ICMPV6) { + if (IN6_IS_ADDR_MULTICAST(&is->is_dst.in6)) + flags |= FI_W_DADDR; + if (out) + hv -= is->is_daddr; + else + hv -= is->is_saddr; + } + } +#endif + + switch (is->is_p) + { +#ifdef USE_INET6 + case IPPROTO_ICMPV6 : +#endif + case IPPROTO_ICMP : + { + struct icmp *ic = (struct icmp *)fin->fin_dp; + +#ifdef USE_INET6 + if ((is->is_p == IPPROTO_ICMPV6) && + ((ic->icmp_type & ICMP6_INFOMSG_MASK) == 0)) + return NULL; +#endif + switch (ic->icmp_type) + { +#ifdef USE_INET6 + case ICMP6_ECHO_REQUEST : + is->is_icmp.ics_type = ICMP6_ECHO_REPLY; + hv += (is->is_icmp.ics_id = ic->icmp_id); + hv += (is->is_icmp.ics_seq = ic->icmp_seq); + break; + case ICMP6_MEMBERSHIP_QUERY : + case ND_ROUTER_SOLICIT : + case ND_NEIGHBOR_SOLICIT : + is->is_icmp.ics_type = ic->icmp_type + 1; + break; +#endif + case ICMP_ECHO : + case ICMP_TSTAMP : + case ICMP_IREQ : + case ICMP_MASKREQ : + is->is_icmp.ics_type = ic->icmp_type; + hv += (is->is_icmp.ics_id = ic->icmp_id); + hv += (is->is_icmp.ics_seq = ic->icmp_seq); + break; + default : + return NULL; + } + ATOMIC_INCL(ips_stats.iss_icmp); + is->is_age = fr_icmptimeout; + break; + } + case IPPROTO_TCP : + { + tcp = (tcphdr_t *)fin->fin_dp; + + if (tcp->th_flags & TH_RST) + return NULL; + /* + * 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; + } + is->is_send = ntohl(tcp->th_seq) + fin->fin_dlen - + (tcp->th_off << 2) + + ((tcp->th_flags & TH_SYN) ? 1 : 0) + + ((tcp->th_flags & TH_FIN) ? 1 : 0); + is->is_maxsend = is->is_send; + is->is_dend = 0; + is->is_maxdwin = 1; + 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. + */ + ATOMIC_INCL(ips_stats.iss_tcp); + break; + } + case IPPROTO_UDP : + { + tcp = (tcphdr_t *)fin->fin_dp; + + 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; + } + ATOMIC_INCL(ips_stats.iss_udp); + is->is_age = fr_udptimeout; + break; + } + default : + return NULL; + } + + KMALLOC(is, ipstate_t *); + if (is == NULL) { + ATOMIC_INCL(ips_stats.iss_nomem); + return NULL; + } + bcopy((char *)&ips, (char *)is, sizeof(*is)); + hv %= fr_statesize; + is->is_hv = hv; + is->is_rule = fin->fin_fr; + if (is->is_rule != NULL) { + ATOMIC_INC32(is->is_rule->fr_ref); + pass = is->is_rule->fr_flags; + } else + pass = fr_flags; + WRITE_ENTER(&ipf_state); + + is->is_pass = pass; + is->is_pkts = 1; + is->is_bytes = fin->fin_dlen + fin->fin_hlen; + /* + * 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_v = fin->fin_fi.fi_v; + 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_WILDP|FI_WILDA); + if (flags & (FI_WILDP|FI_WILDA)) + ips_wild++; + is->is_ifp[1 - out] = NULL; + is->is_ifp[out] = fin->fin_ifp; +#ifdef _KERNEL + strncpy(is->is_ifname[out], IFNAME(fin->fin_ifp), IFNAMSIZ); +#endif + is->is_ifname[1 - out][0] = '\0'; + if (pass & FR_LOGFIRST) + is->is_pass &= ~(FR_LOGFIRST|FR_LOG); + fr_stinsert(is); + if (is->is_p == IPPROTO_TCP) { + MUTEX_ENTER(&is->is_lock); + fr_tcp_age(&is->is_age, is->is_state, fin, + 0); /* 0 = packet from the source */ + MUTEX_EXIT(&is->is_lock); + } +#ifdef IPFILTER_LOG + ipstate_log(is, ISL_NEW); +#endif + RWLOCK_EXIT(&ipf_state); + fin->fin_rev = IP6NEQ(is->is_dst, fin->fin_fi.fi_dst); + if ((fin->fin_fi.fi_fl & FI_FRAG) && (pass & FR_KEEPFRAG)) + 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 = IP6EQ(fin->fin_fi.fi_src, is->is_src); + 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 + fin->fin_dlen - (tcp->th_off << 2) + + ((tcp->th_flags & TH_SYN) ? 1 : 0) + + ((tcp->th_flags & TH_FIN) ? 1 : 0); + + MUTEX_ENTER(&is->is_lock); + 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; + } 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, 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_INCL(ips_stats.iss_hits); + /* + * Nearing end of connection, start timeout. + */ + /* source ? 0 : 1 -> !source */ + fr_tcp_age(&is->is_age, is->is_state, fin, !source); + ret = 1; + } + MUTEX_EXIT(&is->is_lock); + return ret; +} + + +static int fr_matchsrcdst(is, src, dst, fin, tcp) +ipstate_t *is; +union i6addr 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 = IP6NEQ(is->is_dst, dst); + 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 = is->is_flags & FI_WILDA; + sp = 0; + dp = 0; + } + + if (rev == 0) { + if (!out) { + if (is->is_ifpin == NULL || 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 == NULL || 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 ( + (IP6EQ(is->is_dst, dst) || (flags & FI_W_DADDR)) && + (IP6EQ(is->is_src, src) || (flags & FI_W_SADDR)) && + (!tcp || ((sp == is->is_sport || flags & FI_W_SPORT) && + (dp == is->is_dport || flags & FI_W_DPORT)))) { + ret = 1; + } + } else { + if ( + (IP6EQ(is->is_dst, src) || (flags & FI_W_DADDR)) && + (IP6EQ(is->is_src, dst) || (flags & FI_W_SADDR)) && + (!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); + ips_wild--; + } + + ret = -1; + + if (!rev) { + if (out) { + if (!is->is_ifpout) + ret = 1; + } else { + if (!is->is_ifpin) + ret = 0; + } + } else { + if (out) { + if (!is->is_ifpin) + ret = 0; + } else { + if (!is->is_ifpout) + ret = 1; + } + } + + if (ret >= 0) { + is->is_ifp[ret] = ifp; +#ifdef _KERNEL + strncpy(is->is_ifname[out], IFNAME(fin->fin_ifp), + sizeof(is->is_ifname[1])); +#endif + } +#ifdef _KERNEL + if (ret >= 0) { + strncpy(is->is_ifname[out], IFNAME(fin->fin_ifp), + sizeof(is->is_ifname[1])); + } +#endif + return 1; +} + +static int fr_matchicmpqueryreply(v, is, icmp) +int v; +ipstate_t *is; +icmphdr_t *icmp; +{ + if (v == 4) { + /* + * If we matched its type on the way in, then when going out + * it will still be the same type. + */ + if (((icmp->icmp_type == is->is_type) || + (icmpreplytype4[is->is_type] == icmp->icmp_type)) && + (icmp->icmp_id == is->is_icmp.ics_id) && + (icmp->icmp_seq == is->is_icmp.ics_seq)) { + return 1; + }; + } +#ifdef USE_INET6 + else if (is->is_v == 6) { + if ((is->is_type == ICMP6_ECHO_REPLY) && + (icmp->icmp_type == ICMP6_ECHO_REQUEST) && + (icmp->icmp_id == is->is_icmp.ics_id) && + (icmp->icmp_seq == is->is_icmp.ics_seq)) { + return 1; + }; + } +#endif + return 0; +} + +static frentry_t *fr_checkicmpmatchingstate(ip, fin) +ip_t *ip; +fr_info_t *fin; +{ + register ipstate_t *is, **isp; + register u_short sport, dport; + register u_char pr; + union i6addr dst, src; + struct icmp *ic; + u_short savelen; + icmphdr_t *icmp; + fr_info_t ofin; + int type, len; + tcphdr_t *tcp; + frentry_t *fr; + ip_t *oip; + u_int hv; + + /* + * 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_v != 4) || (ip->ip_hl != 5)) || + (fin->fin_plen < ICMPERR_MINPKTLEN)) + return NULL; + ic = (struct icmp *)fin->fin_dp; + 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 *)ic + ICMPERR_ICMPHLEN); + if (fin->fin_plen < ICMPERR_MAXPKTLEN + ((oip->ip_hl - 5) << 2)) + return NULL; + + /* + * Sanity checks. + */ + len = fin->fin_dlen - ICMPERR_ICMPHLEN; + if ((len <= 0) || ((oip->ip_hl << 2) > len)) + return NULL; + + /* + * Is the buffer big enough for all of it ? It's the size of the IP + * header claimed in the encapsulated part which is of concern. It + * may be too big to be in this buffer but not so big that it's + * outside the ICMP packet, leading to TCP deref's causing problems. + * This is possible because we don't know how big oip_hl is when we + * do the pullup early in fr_check() and thus can't gaurantee it is + * all here now. + */ +#ifdef _KERNEL + { + mb_t *m; + +# if SOLARIS + m = fin->fin_qfm; + if ((char *)oip + len > (char *)m->b_wptr) + return NULL; +# else + m = *(mb_t **)fin->fin_mp; + if ((char *)oip + len > (char *)ip + m->m_len) + return NULL; +# endif + } +#endif + + /* + * in the IPv4 case we must zero the i6addr union otherwise + * the IP6EQ and IP6NEQ macros produce the wrong results because + * of the 'junk' in the unused part of the union + */ + bzero((char *)&src, sizeof(src)); + bzero((char *)&dst, sizeof(dst)); + + if (oip->ip_p == IPPROTO_ICMP) { + icmp = (icmphdr_t *)((char *)oip + (oip->ip_hl << 2)); + + /* + * a ICMP error can only be generated as a result of an + * ICMP query, not as the response on an ICMP error + * + * XXX theoretically ICMP_ECHOREP and the other reply's are + * ICMP query's as well, but adding them here seems strange XXX + */ + if ((icmp->icmp_type != ICMP_ECHO) && + (icmp->icmp_type != ICMP_TSTAMP) && + (icmp->icmp_type != ICMP_IREQ) && + (icmp->icmp_type != ICMP_MASKREQ)) + return NULL; + + /* + * perform a lookup of the ICMP packet in the state table + */ + hv = (pr = oip->ip_p); + src.in4 = oip->ip_src; + hv += src.in4.s_addr; + dst.in4 = oip->ip_dst; + hv += dst.in4.s_addr; + hv += icmp->icmp_id; + hv += icmp->icmp_seq; + hv %= fr_statesize; + + savelen = oip->ip_len; + oip->ip_len = len; + ofin.fin_v = 4; + fr_makefrip(oip->ip_hl << 2, oip, &ofin); + oip->ip_len = savelen; + 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_hnext) + if ((is->is_p == pr) && (is->is_v == 4) && + fr_matchsrcdst(is, src, dst, &ofin, NULL) && + fr_matchicmpqueryreply(is->is_v, is, icmp)) { + ips_stats.iss_hits++; + is->is_pkts++; + is->is_bytes += ip->ip_len; + fr = is->is_rule; + RWLOCK_EXIT(&ipf_state); + return fr; + } + RWLOCK_EXIT(&ipf_state); + 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); + src.in4 = oip->ip_src; + hv += src.in4.s_addr; + dst.in4 = oip->ip_dst; + hv += dst.in4.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. + */ + savelen = oip->ip_len; + oip->ip_len = len; + ofin.fin_v = 4; + fr_makefrip(oip->ip_hl << 2, oip, &ofin); + oip->ip_len = savelen; + 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_hnext) { + /* + * 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) && (is->is_v == 4) && + fr_matchsrcdst(is, src, dst, &ofin, tcp)) { + fr = is->is_rule; + ips_stats.iss_hits++; + is->is_pkts++; + is->is_bytes += fin->fin_plen; + /* + * 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; +} + + +static void fr_ipsmove(isp, is, hv) +ipstate_t **isp, *is; +u_int hv; +{ + u_int hvm; + + hvm = is->is_hv; + /* + * Remove the hash from the old location... + */ + if (is->is_hnext) + is->is_hnext->is_phnext = isp; + *isp = is->is_hnext; + if (ips_table[hvm] == NULL) + ips_stats.iss_inuse--; + + /* + * ...and put the hash in the new one. + */ + hvm = hv % fr_statesize; + is->is_hv = hvm; + isp = &ips_table[hvm]; + if (*isp) + (*isp)->is_phnext = &is->is_hnext; + else + ips_stats.iss_inuse++; + is->is_phnext = isp; + is->is_hnext = *isp; + *isp = is; +} + + +/* + * Check if a packet has a registered state. + */ +frentry_t *fr_checkstate(ip, fin) +ip_t *ip; +fr_info_t *fin; +{ + union i6addr dst, src; + register ipstate_t *is, **isp; + register u_char pr; + u_int hv, hvm, hlen, tryagain, pass, v; + struct icmp *ic; + frentry_t *fr; + tcphdr_t *tcp; + + if (fr_state_lock || (fin->fin_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 = fin->fin_fi.fi_p); + src = fin->fin_fi.fi_src; + dst = fin->fin_fi.fi_dst; + hv += src.in4.s_addr; + hv += dst.in4.s_addr; + + /* + * Search the hash table for matching packet header info. + */ + v = fin->fin_fi.fi_v; + switch (fin->fin_fi.fi_p) + { +#ifdef USE_INET6 + case IPPROTO_ICMPV6 : + if (v == 6) { + if (fin->fin_out) + hv -= dst.in4.s_addr; + else + hv -= src.in4.s_addr; + if ((ic->icmp_type == ICMP6_ECHO_REQUEST) || + (ic->icmp_type == ICMP6_ECHO_REPLY)) { + hv += ic->icmp_id; + hv += ic->icmp_seq; + } + } +#endif + case IPPROTO_ICMP : + if (v == 4) { + 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_hnext) { + if ((is->is_p == pr) && (is->is_v == v) && + fr_matchsrcdst(is, src, dst, fin, NULL) && + fr_matchicmpqueryreply(v, is, ic)) { + 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. + */ +#ifdef USE_INET6 + if (v == 6) + fr = fr_checkicmp6matchingstate((ip6_t *)ip, fin); + else +#endif + fr = fr_checkicmpmatchingstate(ip, fin); + if (fr) + return fr; + break; + case IPPROTO_TCP : + { + register u_short dport, sport; + register int i; + + i = tcp->th_flags; + /* + * Just plain ignore RST flag set with either FIN or SYN. + */ + if ((i & TH_RST) && + ((i & (TH_FIN|TH_SYN|TH_RST)) != TH_RST)) + break; + case IPPROTO_UDP : + dport = tcp->th_dport; + sport = tcp->th_sport; + tryagain = 0; + hv += dport; + hv += sport; + READ_ENTER(&ipf_state); +retry_tcpudp: + hvm = hv % fr_statesize; + for (isp = &ips_table[hvm]; (is = *isp); isp = &is->is_hnext) + if ((is->is_p == pr) && (is->is_v == v) && + fr_matchsrcdst(is, src, dst, fin, tcp)) { + if ((pr == IPPROTO_TCP)) { + if (!fr_tcpstate(is, fin, ip, tcp)) { + continue; + } + } + break; + } + if (is != NULL) { + if (tryagain && + !(is->is_flags & (FI_WILDP|FI_WILDA))) { + hv += dport; + hv += sport; + fr_ipsmove(isp, is, hv); + MUTEX_DOWNGRADE(&ipf_state); + } + break; + } + RWLOCK_EXIT(&ipf_state); + if (!tryagain && ips_wild) { + hv -= dport; + hv -= sport; + tryagain = 1; + WRITE_ENTER(&ipf_state); + goto retry_tcpudp; + } + break; + } + default : + break; + } + if (is == NULL) { + ATOMIC_INCL(ips_stats.iss_miss); + return NULL; + } + MUTEX_ENTER(&is->is_lock); + is->is_bytes += fin->fin_plen; + ips_stats.iss_hits++; + is->is_pkts++; + MUTEX_EXIT(&is->is_lock); + fr = is->is_rule; + fin->fin_fr = fr; + pass = is->is_pass; +#ifndef _KERNEL + if (tcp->th_flags & TCP_CLOSE) + fr_delstate(is); +#endif + RWLOCK_EXIT(&ipf_state); + if ((fin->fin_fi.fi_fl & FI_FRAG) && (pass & FR_KEEPFRAG)) + ipfr_newfrag(ip, fin, pass ^ FR_KEEPSTATE); + return fr; +} + + +void ip_statesync(ifp) +void *ifp; +{ + register ipstate_t *is; + + WRITE_ENTER(&ipf_state); + for (is = ips_list; is; is = is->is_next) { + if (is->is_ifpin == ifp) { + is->is_ifpin = GETUNIT(is->is_ifname[0], is->is_v); + if (!is->is_ifpin) + is->is_ifpin = (void *)-1; + } + if (is->is_ifpout == ifp) { + is->is_ifpout = GETUNIT(is->is_ifname[1], is->is_v); + if (!is->is_ifpout) + is->is_ifpout = (void *)-1; + } + } + RWLOCK_EXIT(&ipf_state); +} + + +/* + * Must always be called with fr_ipfstate held as a write lock. + */ +static void fr_delstate(is) +ipstate_t *is; +{ + frentry_t *fr; + + if (is->is_flags & (FI_WILDP|FI_WILDA)) + ips_wild--; + if (is->is_next) + is->is_next->is_pnext = is->is_pnext; + *is->is_pnext = is->is_next; + if (is->is_hnext) + is->is_hnext->is_phnext = is->is_phnext; + *is->is_phnext = is->is_hnext; + if (ips_table[is->is_hv] == NULL) + ips_stats.iss_inuse--; + + fr = is->is_rule; + if (fr != NULL) { + fr->fr_ref--; + if (fr->fr_ref == 0) { + KFREE(fr); + } + } +#ifdef _KERNEL + MUTEX_DESTROY(&is->is_lock); +#endif + KFREE(is); + ips_num--; +} + + +/* + * Free memory in use by all state info. kept. + */ +void fr_stateunload() +{ + register ipstate_t *is; + + WRITE_ENTER(&ipf_state); + while ((is = ips_list)) + fr_delstate(is); + 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 ipstate_t *is, **isp; +#if defined(_KERNEL) && !SOLARIS + int s; +#endif + + SPL_NET(s); + WRITE_ENTER(&ipf_state); + for (isp = &ips_list; (is = *isp); ) + if (is->is_age && !--is->is_age) { + if (is->is_p == IPPROTO_TCP) + ips_stats.iss_fin++; + else + ips_stats.iss_expire++; +#ifdef IPFILTER_LOG + ipstate_log(is, ISL_EXPIRE); +#endif + fr_delstate(is); + } 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); +} + + +/* + * Original idea freom Pradeep Krishnan for use primarily with NAT code. + * (pkrishna@netcom.com) + * + * Rewritten by Arjan de Vet <Arjan.deVet@adv.iae.nl>, 2000-07-29: + * + * - (try to) base state transitions on real evidence only, + * i.e. packets that are sent and have been received by ipfilter; + * diagram 18.12 of TCP/IP volume 1 by W. Richard Stevens was used. + * + * - deal with half-closed connections correctly; + * + * - store the state of the source in state[0] such that ipfstat + * displays the state as source/dest instead of dest/source; the calls + * to fr_tcp_age have been changed accordingly. + * + * Parameters: + * + * state[0] = state of source (host that initiated connection) + * state[1] = state of dest (host that accepted the connection) + * + * dir == 0 : a packet from source to dest + * dir == 1 : a packet from dest to source + * + */ +void fr_tcp_age(age, state, fin, dir) +u_long *age; +u_char *state; +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 = fin->fin_plen - 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; /* default 4 mins */ + + switch(state[dir]) + { + case TCPS_CLOSED: /* 0 */ + if ((flags & TH_OPENING) == TH_OPENING) { + /* + * 'dir' received an S and sends SA in response, + * CLOSED -> SYN_RECEIVED + */ + state[dir] = TCPS_SYN_RECEIVED; + *age = fr_tcptimeout; + } else if ((flags & (TH_SYN|TH_ACK)) == TH_SYN) { + /* 'dir' sent S, CLOSED -> SYN_SENT */ + state[dir] = TCPS_SYN_SENT; + *age = fr_tcptimeout; + } + /* + * The next piece of code makes it possible to get + * already established connections into the state table + * after a restart or reload of the filter rules; this + * does not work when a strict 'flags S keep state' is + * used for tcp connections of course + */ + if ((flags & (TH_FIN|TH_SYN|TH_RST|TH_ACK)) == TH_ACK) { + /* we saw an A, guess 'dir' is in ESTABLISHED mode */ + state[dir] = TCPS_ESTABLISHED; + *age = fr_tcpidletimeout; + } + /* + * TODO: besides regular ACK packets we can have other + * packets as well; it is yet to be determined how we + * should initialize the states in those cases + */ + break; + + case TCPS_LISTEN: /* 1 */ + /* NOT USED */ + break; + + case TCPS_SYN_SENT: /* 2 */ + if ((flags & (TH_SYN|TH_FIN|TH_ACK)) == TH_ACK) { + /* + * We see an A from 'dir' which is in SYN_SENT + * state: 'dir' sent an A in response to an SA + * which it received, SYN_SENT -> ESTABLISHED + */ + state[dir] = TCPS_ESTABLISHED; + *age = fr_tcpidletimeout; + } else if (flags & TH_FIN) { + /* + * We see an F from 'dir' which is in SYN_SENT + * state and wants to close its side of the + * connection; SYN_SENT -> FIN_WAIT_1 + */ + state[dir] = TCPS_FIN_WAIT_1; + *age = fr_tcpidletimeout; /* or fr_tcptimeout? */ + } else if ((flags & TH_OPENING) == TH_OPENING) { + /* + * We see an SA from 'dir' which is already in + * SYN_SENT state, this means we have a + * simultaneous open; SYN_SENT -> SYN_RECEIVED + */ + state[dir] = TCPS_SYN_RECEIVED; + *age = fr_tcptimeout; + } + break; + + case TCPS_SYN_RECEIVED: /* 3 */ + if ((flags & (TH_SYN|TH_FIN|TH_ACK)) == TH_ACK) { + /* + * We see an A from 'dir' which was in SYN_RECEIVED + * state so it must now be in established state, + * SYN_RECEIVED -> ESTABLISHED + */ + state[dir] = TCPS_ESTABLISHED; + *age = fr_tcpidletimeout; + } else if (flags & TH_FIN) { + /* + * We see an F from 'dir' which is in SYN_RECEIVED + * state and wants to close its side of the connection; + * SYN_RECEIVED -> FIN_WAIT_1 + */ + state[dir] = TCPS_FIN_WAIT_1; + *age = fr_tcpidletimeout; + } + break; + + case TCPS_ESTABLISHED: /* 4 */ + if (flags & TH_FIN) { + /* + * 'dir' closed its side of the connection; this + * gives us a half-closed connection; + * ESTABLISHED -> FIN_WAIT_1 + */ + state[dir] = TCPS_FIN_WAIT_1; + *age = fr_tcphalfclosed; + } else if (flags & TH_ACK) { + /* an ACK, should we exclude other flags here? */ + if (ostate == TCPS_FIN_WAIT_1) { + /* + * We know the other side did an active close, + * so we are ACKing the recvd FIN packet (does + * the window matching code guarantee this?) + * and go into CLOSE_WAIT state; this gives us + * a half-closed connection + */ + state[dir] = TCPS_CLOSE_WAIT; + *age = fr_tcphalfclosed; + } else if (ostate < TCPS_CLOSE_WAIT) + /* + * Still a fully established connection, + * reset timeout + */ + *age = fr_tcpidletimeout; + } + break; + + case TCPS_CLOSE_WAIT: /* 5 */ + if (flags & TH_FIN) { + /* + * Application closed and 'dir' sent a FIN, we're now + * going into LAST_ACK state + */ + *age = fr_tcplastack; + state[dir] = TCPS_LAST_ACK; + } else { + /* + * We remain in CLOSE_WAIT because the other side has + * closed already and we did not close our side yet; + * reset timeout + */ + *age = fr_tcphalfclosed; + } + break; + + case TCPS_FIN_WAIT_1: /* 6 */ + if ((flags & TH_ACK) && ostate > TCPS_CLOSE_WAIT) { + /* + * If the other side is not active anymore it has sent + * us a FIN packet that we are ack'ing now with an ACK; + * this means both sides have now closed the connection + * and we go into TIME_WAIT + */ + /* + * XXX: how do we know we really are ACKing the FIN + * packet here? does the window code guarantee that? + */ + state[dir] = TCPS_TIME_WAIT; + *age = fr_tcptimeout; + } else + /* + * We closed our side of the connection already but the + * other side is still active (ESTABLISHED/CLOSE_WAIT); + * continue with this half-closed connection + */ + *age = fr_tcphalfclosed; + break; + + case TCPS_CLOSING: /* 7 */ + /* NOT USED */ + break; + + case TCPS_LAST_ACK: /* 8 */ + if (flags & TH_ACK) { + if ((flags & TH_PUSH) || dlen) + /* + * There is still data to be delivered, reset + * timeout + */ + *age = fr_tcplastack; + } + /* + * We cannot detect when we go out of LAST_ACK state to CLOSED + * because that is based on the reception of ACK packets; + * ipfilter can only detect that a packet has been sent by a + * host + */ + break; + + case TCPS_FIN_WAIT_2: /* 9 */ + /* NOT USED */ + break; + + case TCPS_TIME_WAIT: /* 10 */ + /* we're in 2MSL timeout now */ + 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_v = is->is_v; + 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 + + +#ifdef USE_INET6 +frentry_t *fr_checkicmp6matchingstate(ip, fin) +ip6_t *ip; +fr_info_t *fin; +{ + register ipstate_t *is, **isp; + register u_short sport, dport; + register u_char pr; + struct icmp6_hdr *ic, *oic; + union i6addr dst, src; + u_short savelen; + fr_info_t ofin; + tcphdr_t *tcp; + frentry_t *fr; + ip6_t *oip; + int type; + u_int hv; + + /* + * 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 ((fin->fin_v != 6) || (fin->fin_plen < ICMP6ERR_MINPKTLEN)) + return NULL; + ic = (struct icmp6_hdr *)fin->fin_dp; + type = ic->icmp6_type; + /* + * If it's not an error type, then return + */ + if ((type != ICMP6_DST_UNREACH) && (type != ICMP6_PACKET_TOO_BIG) && + (type != ICMP6_TIME_EXCEEDED) && (type != ICMP6_PARAM_PROB)) + return NULL; + + oip = (ip6_t *)((char *)ic + ICMPERR_ICMPHLEN); + if (fin->fin_plen < sizeof(*oip)) + return NULL; + + if (oip->ip6_nxt == IPPROTO_ICMPV6) { + oic = (struct icmp6_hdr *)(oip + 1); + /* + * a ICMP error can only be generated as a result of an + * ICMP query, not as the response on an ICMP error + * + * XXX theoretically ICMP_ECHOREP and the other reply's are + * ICMP query's as well, but adding them here seems strange XXX + */ + if (!(oic->icmp6_type & ICMP6_INFOMSG_MASK)) + return NULL; + + /* + * perform a lookup of the ICMP packet in the state table + */ + hv = (pr = oip->ip6_nxt); + src.in6 = oip->ip6_src; + hv += src.in4.s_addr; + dst.in6 = oip->ip6_dst; + hv += dst.in4.s_addr; + hv += oic->icmp6_id; + hv += oic->icmp6_seq; + hv %= fr_statesize; + + oip->ip6_plen = ntohs(oip->ip6_plen); + ofin.fin_v = 6; + fr_makefrip(sizeof(*oip), (ip_t *)oip, &ofin); + oip->ip6_plen = htons(oip->ip6_plen); + 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_hnext) + if ((is->is_p == pr) && + (oic->icmp6_id == is->is_icmp.ics_id) && + (oic->icmp6_seq == is->is_icmp.ics_seq) && + fr_matchsrcdst(is, src, dst, &ofin, NULL)) { + /* + * in the state table ICMP query's are stored + * with the type of the corresponding ICMP + * response. Correct here + */ + if (((is->is_type == ICMP6_ECHO_REPLY) && + (oic->icmp6_type == ICMP6_ECHO_REQUEST)) || + (is->is_type - 1 == oic->icmp6_type )) { + ips_stats.iss_hits++; + is->is_pkts++; + is->is_bytes += fin->fin_plen; + return is->is_rule; + } + } + RWLOCK_EXIT(&ipf_state); + + return NULL; + }; + + if ((oip->ip6_nxt != IPPROTO_TCP) && (oip->ip6_nxt != IPPROTO_UDP)) + return NULL; + tcp = (tcphdr_t *)(oip + 1); + dport = tcp->th_dport; + sport = tcp->th_sport; + + hv = (pr = oip->ip6_nxt); + src.in6 = oip->ip6_src; + hv += src.in4.s_addr; + dst.in6 = oip->ip6_dst; + hv += dst.in4.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. + */ + savelen = oip->ip6_plen; + oip->ip6_plen = ip->ip6_plen - sizeof(*ip) - ICMPERR_ICMPHLEN; + ofin.fin_v = 6; + fr_makefrip(sizeof(*oip), (ip_t *)oip, &ofin); + oip->ip6_plen = savelen; + 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_hnext) { + /* + * 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) && (is->is_v == 6) && + 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 + */ + is->is_pkts++; + is->is_bytes += fin->fin_plen; + /* + * 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; +} +#endif |
