/* $NetBSD: ip_state.c,v 1.7 2005/04/03 15:05:30 martti Exp $ */ /* * Copyright (C) 1995-2003 by Darren Reed. * * See the IPFILTER.LICENCE file for details on licencing. */ #if defined(KERNEL) || defined(_KERNEL) # undef KERNEL # undef _KERNEL # define KERNEL 1 # define _KERNEL 1 #endif #include #include #include #include #if defined(__NetBSD__) && (NetBSD >= 199905) && !defined(IPFILTER_LKM) && \ defined(_KERNEL) # include "opt_ipfilter.h" #endif #if defined(_KERNEL) && defined(__FreeBSD_version) && \ (__FreeBSD_version >= 400000) && !defined(KLD_MODULE) #include "opt_inet6.h" #endif #if !defined(_KERNEL) && !defined(__KERNEL__) # include # include # include # define _KERNEL # ifdef __OpenBSD__ struct file; # endif # include # undef _KERNEL #endif #if defined(_KERNEL) && (__FreeBSD_version >= 220000) # include # include # if (__FreeBSD_version >= 300000) && !defined(IPFILTER_LKM) # include "opt_ipfilter.h" # endif #else # include #endif #include #if !defined(linux) # include #endif #include #if defined(_KERNEL) # include # if !defined(__SVR4) && !defined(__svr4__) # include # endif #endif #if defined(__SVR4) || defined(__svr4__) # include # include # ifdef _KERNEL # include # endif # include # include #endif #include #ifdef sun # include #endif #include #include #include #include #include #if !defined(linux) # include #endif #if !defined(__hpux) && !defined(linux) # include #endif #include #include #include "netinet/ip_compat.h" #include #include "netinet/ip_fil.h" #include "netinet/ip_nat.h" #include "netinet/ip_frag.h" #include "netinet/ip_state.h" #include "netinet/ip_proxy.h" #ifdef IPFILTER_SYNC #include "netinet/ip_sync.h" #endif #ifdef IPFILTER_SCAN #include "netinet/ip_scan.h" #endif #ifdef USE_INET6 #include #endif #if (__FreeBSD_version >= 300000) # include # if defined(_KERNEL) && !defined(IPFILTER_LKM) # include # include # endif #endif /* END OF INCLUDES */ #if !defined(lint) #if defined(__NetBSD__) #include __KERNEL_RCSID(0, "$NetBSD: ip_state.c,v 1.7 2005/04/03 15:05:30 martti Exp $"); #else static const char sccsid[] = "@(#)ip_state.c 1.8 6/5/96 (C) 1993-2000 Darren Reed"; static const char rcsid[] = "@(#)Id: ip_state.c,v 2.186.2.29 2005/03/28 10:47:54 darrenr Exp"; #endif #endif static ipstate_t **ips_table = NULL; static u_long *ips_seed = NULL; static int ips_num = 0; static u_long ips_last_force_flush = 0; ips_stat_t ips_stats; #ifdef USE_INET6 static ipstate_t *fr_checkicmp6matchingstate __P((fr_info_t *)); #endif static ipstate_t *fr_matchsrcdst __P((fr_info_t *, ipstate_t *, i6addr_t *, i6addr_t *, tcphdr_t *, u_32_t)); static ipstate_t *fr_checkicmpmatchingstate __P((fr_info_t *)); static int fr_state_flush __P((int, int)); static ips_stat_t *fr_statetstats __P((void)); static void fr_delstate __P((ipstate_t *, int)); static int fr_state_remove __P((caddr_t)); static void fr_ipsmove __P((ipstate_t *, u_int)); static int fr_tcpstate __P((fr_info_t *, tcphdr_t *, ipstate_t *)); static int fr_tcpoptions __P((fr_info_t *, tcphdr_t *, tcpdata_t *)); static ipstate_t *fr_stclone __P((fr_info_t *, tcphdr_t *, ipstate_t *)); static void fr_fixinisn __P((fr_info_t *, ipstate_t *)); static void fr_fixoutisn __P((fr_info_t *, ipstate_t *)); static void fr_checknewisn __P((fr_info_t *, ipstate_t *)); int fr_stputent __P((caddr_t)); int fr_stgetent __P((caddr_t)); #define ONE_DAY IPF_TTLVAL(1 * 86400) /* 1 day */ #define FIVE_DAYS (5 * ONE_DAY) #define DOUBLE_HASH(x) (((x) + ips_seed[(x) % fr_statesize]) % fr_statesize) u_long fr_tcpidletimeout = FIVE_DAYS, fr_tcpclosewait = IPF_TTLVAL(2 * TCP_MSL), fr_tcplastack = IPF_TTLVAL(2 * TCP_MSL), fr_tcptimeout = IPF_TTLVAL(2 * TCP_MSL), fr_tcpclosed = IPF_TTLVAL(60), fr_tcphalfclosed = IPF_TTLVAL(2 * 3600), /* 2 hours */ fr_udptimeout = IPF_TTLVAL(120), fr_udpacktimeout = IPF_TTLVAL(12), fr_icmptimeout = IPF_TTLVAL(60), fr_icmpacktimeout = IPF_TTLVAL(6), fr_iptimeout = IPF_TTLVAL(60); int fr_statemax = IPSTATE_MAX, fr_statesize = IPSTATE_SIZE; int fr_state_doflush = 0, fr_state_lock = 0, fr_state_maxbucket = 0, fr_state_maxbucket_reset = 1, fr_state_init = 0; ipftq_t ips_tqtqb[IPF_TCP_NSTATES], ips_udptq, ips_udpacktq, ips_iptq, ips_icmptq, ips_icmpacktq, *ips_utqe = NULL; #ifdef IPFILTER_LOG int ipstate_logging = 1; #else int ipstate_logging = 0; #endif ipstate_t *ips_list = NULL; /* ------------------------------------------------------------------------ */ /* Function: fr_stateinit */ /* Returns: int - 0 == success, -1 == failure */ /* Parameters: Nil */ /* */ /* Initialise all the global variables used within the state code. */ /* This action also includes initiailising locks. */ /* ------------------------------------------------------------------------ */ int fr_stateinit() { int i; KMALLOCS(ips_table, ipstate_t **, fr_statesize * sizeof(ipstate_t *)); if (ips_table == NULL) return -1; bzero((char *)ips_table, fr_statesize * sizeof(ipstate_t *)); KMALLOCS(ips_seed, u_long *, fr_statesize * sizeof(*ips_seed)); if (ips_seed == NULL) return -2; for (i = 0; i < fr_statesize; i++) { /* * XXX - ips_seed[X] should be a random number of sorts. */ #if (__FreeBSD_version >= 400000) ips_seed[i] = arc4random(); #else ips_seed[i] = ((u_long)ips_seed + i) * fr_statesize; ips_seed[i] ^= 0xa5a55a5a; ips_seed[i] *= (u_long)ips_seed; ips_seed[i] ^= 0x5a5aa5a5; ips_seed[i] *= fr_statemax; #endif } /* 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; #ifdef USE_INET6 /* fill icmp reply type table */ for (i = 0; i <= ICMP6_MAXTYPE; i++) icmpreplytype6[i] = -1; icmpreplytype6[ICMP6_ECHO_REQUEST] = ICMP6_ECHO_REPLY; icmpreplytype6[ICMP6_MEMBERSHIP_QUERY] = ICMP6_MEMBERSHIP_REPORT; icmpreplytype6[ICMP6_NI_QUERY] = ICMP6_NI_REPLY; icmpreplytype6[ND_ROUTER_SOLICIT] = ND_ROUTER_ADVERT; icmpreplytype6[ND_NEIGHBOR_SOLICIT] = ND_NEIGHBOR_ADVERT; #endif KMALLOCS(ips_stats.iss_bucketlen, u_long *, fr_statesize * sizeof(u_long)); if (ips_stats.iss_bucketlen == NULL) return -1; bzero((char *)ips_stats.iss_bucketlen, fr_statesize * sizeof(u_long)); if (fr_state_maxbucket == 0) { for (i = fr_statesize; i > 0; i >>= 1) fr_state_maxbucket++; fr_state_maxbucket *= 2; } fr_sttab_init(ips_tqtqb); ips_tqtqb[IPF_TCP_NSTATES - 1].ifq_next = &ips_udptq; ips_udptq.ifq_ttl = (u_long)fr_udptimeout; ips_udptq.ifq_ref = 1; ips_udptq.ifq_head = NULL; ips_udptq.ifq_tail = &ips_udptq.ifq_head; MUTEX_INIT(&ips_udptq.ifq_lock, "ipftq udp tab"); ips_udptq.ifq_next = &ips_udpacktq; ips_udpacktq.ifq_ttl = (u_long)fr_udpacktimeout; ips_udpacktq.ifq_ref = 1; ips_udpacktq.ifq_head = NULL; ips_udpacktq.ifq_tail = &ips_udpacktq.ifq_head; MUTEX_INIT(&ips_udpacktq.ifq_lock, "ipftq udpack tab"); ips_udpacktq.ifq_next = &ips_icmptq; ips_icmptq.ifq_ttl = (u_long)fr_icmptimeout; ips_icmptq.ifq_ref = 1; ips_icmptq.ifq_head = NULL; ips_icmptq.ifq_tail = &ips_icmptq.ifq_head; MUTEX_INIT(&ips_icmptq.ifq_lock, "ipftq icmp tab"); ips_icmptq.ifq_next = &ips_icmpacktq; ips_icmpacktq.ifq_ttl = (u_long)fr_icmpacktimeout; ips_icmpacktq.ifq_ref = 1; ips_icmpacktq.ifq_head = NULL; ips_icmpacktq.ifq_tail = &ips_icmpacktq.ifq_head; MUTEX_INIT(&ips_icmpacktq.ifq_lock, "ipftq icmpack tab"); ips_icmpacktq.ifq_next = &ips_iptq; ips_iptq.ifq_ttl = (u_long)fr_iptimeout; ips_iptq.ifq_ref = 1; ips_iptq.ifq_head = NULL; ips_iptq.ifq_tail = &ips_iptq.ifq_head; MUTEX_INIT(&ips_iptq.ifq_lock, "ipftq ip tab"); ips_iptq.ifq_next = NULL; RWLOCK_INIT(&ipf_state, "ipf IP state rwlock"); MUTEX_INIT(&ipf_stinsert, "ipf state insert mutex"); fr_state_init = 1; ips_last_force_flush = fr_ticks; return 0; } /* ------------------------------------------------------------------------ */ /* Function: fr_stateunload */ /* Returns: Nil */ /* Parameters: Nil */ /* */ /* Release and destroy any resources acquired or initialised so that */ /* IPFilter can be unloaded or re-initialised. */ /* ------------------------------------------------------------------------ */ void fr_stateunload() { ipftq_t *ifq, *ifqnext; ipstate_t *is; while ((is = ips_list) != NULL) fr_delstate(is, 0); /* * Proxy timeout queues are not cleaned here because although they * exist on the state list, appr_unload is called after fr_stateunload * and the proxies actually are responsible for them being created. * Should the proxy timeouts have their own list? There's no real * justification as this is the only complicationA */ for (ifq = ips_utqe; ifq != NULL; ifq = ifqnext) { ifqnext = ifq->ifq_next; if (((ifq->ifq_flags & IFQF_PROXY) == 0) && (fr_deletetimeoutqueue(ifq) == 0)) fr_freetimeoutqueue(ifq); } ips_stats.iss_inuse = 0; ips_num = 0; if (fr_state_init == 1) { fr_sttab_destroy(ips_tqtqb); MUTEX_DESTROY(&ips_udptq.ifq_lock); MUTEX_DESTROY(&ips_icmptq.ifq_lock); MUTEX_DESTROY(&ips_udpacktq.ifq_lock); MUTEX_DESTROY(&ips_icmpacktq.ifq_lock); MUTEX_DESTROY(&ips_iptq.ifq_lock); } if (ips_table != NULL) { KFREES(ips_table, fr_statesize * sizeof(*ips_table)); ips_table = NULL; } if (ips_seed != NULL) { KFREES(ips_seed, fr_statesize * sizeof(*ips_seed)); ips_seed = NULL; } if (ips_stats.iss_bucketlen != NULL) { KFREES(ips_stats.iss_bucketlen, fr_statesize * sizeof(u_long)); ips_stats.iss_bucketlen = NULL; } if (fr_state_maxbucket_reset == 1) fr_state_maxbucket = 0; if (fr_state_init == 1) { fr_state_init = 0; RW_DESTROY(&ipf_state); MUTEX_DESTROY(&ipf_stinsert); } } /* ------------------------------------------------------------------------ */ /* Function: fr_statetstats */ /* Returns: ips_state_t* - pointer to state stats structure */ /* Parameters: Nil */ /* */ /* Put all the current numbers and pointers into a single struct and return */ /* a pointer to it. */ /* ------------------------------------------------------------------------ */ static ips_stat_t *fr_statetstats() { ips_stats.iss_active = ips_num; ips_stats.iss_statesize = fr_statesize; ips_stats.iss_statemax = fr_statemax; ips_stats.iss_table = ips_table; ips_stats.iss_list = ips_list; ips_stats.iss_ticks = fr_ticks; return &ips_stats; } /* ------------------------------------------------------------------------ */ /* Function: fr_state_remove */ /* Returns: int - 0 == success, != 0 == failure */ /* Parameters: data(I) - pointer to state structure to delete from table */ /* */ /* Search for a state structure that matches the one passed, according to */ /* the IP addresses and other protocol specific information. */ /* ------------------------------------------------------------------------ */ static int fr_state_remove(data) caddr_t data; { ipstate_t *sp, st; int error; sp = &st; error = fr_inobj(data, &st, IPFOBJ_IPSTATE); if (error) return EFAULT; WRITE_ENTER(&ipf_state); for (sp = ips_list; sp; sp = sp->is_next) if ((sp->is_p == st.is_p) && (sp->is_v == st.is_v) && !bcmp((caddr_t)&sp->is_src, (caddr_t)&st.is_src, sizeof(st.is_src)) && !bcmp((caddr_t)&sp->is_dst, (caddr_t)&st.is_src, sizeof(st.is_dst)) && !bcmp((caddr_t)&sp->is_ps, (caddr_t)&st.is_ps, sizeof(st.is_ps))) { fr_delstate(sp, ISL_REMOVE); RWLOCK_EXIT(&ipf_state); return 0; } RWLOCK_EXIT(&ipf_state); return ESRCH; } /* ------------------------------------------------------------------------ */ /* Function: fr_state_ioctl */ /* Returns: int - 0 == success, != 0 == failure */ /* Parameters: data(I) - pointer to ioctl data */ /* cmd(I) - ioctl command integer */ /* mode(I) - file mode bits used with open */ /* */ /* Processes an ioctl call made to operate on the IP Filter state device. */ /* ------------------------------------------------------------------------ */ int fr_state_ioctl(data, cmd, mode) caddr_t data; ioctlcmd_t cmd; int mode; { int arg, ret, error = 0; switch (cmd) { /* * Delete an entry from the state table. */ case SIOCDELST : error = fr_state_remove(data); break; /* * Flush the state table */ case SIOCIPFFL : BCOPYIN(data, (char *)&arg, sizeof(arg)); if (arg == 0 || arg == 1) { WRITE_ENTER(&ipf_state); ret = fr_state_flush(arg, 4); RWLOCK_EXIT(&ipf_state); BCOPYOUT((char *)&ret, data, sizeof(ret)); } else error = EINVAL; break; #ifdef USE_INET6 case SIOCIPFL6 : BCOPYIN(data, (char *)&arg, sizeof(arg)); if (arg == 0 || arg == 1) { WRITE_ENTER(&ipf_state); ret = fr_state_flush(arg, 6); RWLOCK_EXIT(&ipf_state); BCOPYOUT((char *)&ret, data, sizeof(ret)); } else error = EINVAL; break; #endif #ifdef IPFILTER_LOG /* * Flush the state log. */ case SIOCIPFFB : if (!(mode & FWRITE)) error = EPERM; else { int tmp; tmp = ipflog_clear(IPL_LOGSTATE); BCOPYOUT((char *)&tmp, data, sizeof(tmp)); } break; /* * Turn logging of state information on/off. */ case SIOCSETLG : if (!(mode & FWRITE)) error = EPERM; else { BCOPYIN((char *)data, (char *)&ipstate_logging, sizeof(ipstate_logging)); } break; /* * Return the current state of logging. */ case SIOCGETLG : BCOPYOUT((char *)&ipstate_logging, (char *)data, sizeof(ipstate_logging)); break; /* * Return the number of bytes currently waiting to be read. */ case FIONREAD : arg = iplused[IPL_LOGSTATE]; /* returned in an int */ BCOPYOUT((char *)&arg, data, sizeof(arg)); break; #endif /* * Get the current state statistics. */ case SIOCGETFS : error = fr_outobj(data, fr_statetstats(), IPFOBJ_STATESTAT); break; /* * Lock/Unlock the state table. (Locking prevents any changes, which * means no packets match). */ case SIOCSTLCK : fr_lock(data, &fr_state_lock); break; /* * Add an entry to the current state table. */ case SIOCSTPUT : if (!fr_state_lock) { error = EACCES; break; } error = fr_stputent(data); break; /* * Get a state table entry. */ case SIOCSTGET : if (!fr_state_lock) { error = EACCES; break; } error = fr_stgetent(data); break; default : error = EINVAL; break; } return error; } /* ------------------------------------------------------------------------ */ /* Function: fr_stgetent */ /* Returns: int - 0 == success, != 0 == failure */ /* Parameters: data(I) - pointer to state structure to retrieve from table */ /* */ /* Copy out state information from the kernel to a user space process. If */ /* there is a filter rule associated with the state entry, copy that out */ /* as well. The entry to copy out is taken from the value of "ips_next" in */ /* the struct passed in and if not null and not found in the list of current*/ /* state entries, the retrieval fails. */ /* ------------------------------------------------------------------------ */ int fr_stgetent(data) caddr_t data; { ipstate_t *is, *isn; ipstate_save_t ips; int error; error = fr_inobj(data, &ips, IPFOBJ_STATESAVE); if (error) return EFAULT; isn = ips.ips_next; if (isn == NULL) { 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)); ips.ips_rule = isn->is_rule; if (isn->is_rule != NULL) bcopy((char *)isn->is_rule, (char *)&ips.ips_fr, sizeof(ips.ips_fr)); error = fr_outobj(data, &ips, IPFOBJ_STATESAVE); if (error) return EFAULT; return 0; } /* ------------------------------------------------------------------------ */ /* Function: fr_stputent */ /* Returns: int - 0 == success, != 0 == failure */ /* Parameters: data(I) - pointer to state information struct */ /* */ /* This function implements the SIOCSTPUT ioctl: insert a state entry into */ /* the state table. If the state info. includes a pointer to a filter rule */ /* then also add in an orphaned rule (will not show up in any "ipfstat -io" */ /* output. */ /* ------------------------------------------------------------------------ */ int fr_stputent(data) caddr_t data; { ipstate_t *is, *isn; ipstate_save_t ips; int error, out, i; frentry_t *fr; char *name; error = fr_inobj(data, &ips, IPFOBJ_STATESAVE); if (error) return EFAULT; KMALLOC(isn, ipstate_t *); if (isn == NULL) return ENOMEM; bcopy((char *)&ips.ips_is, (char *)isn, sizeof(*isn)); bzero((char *)isn, offsetof(struct ipstate, is_pkts)); isn->is_sti.tqe_pnext = NULL; isn->is_sti.tqe_next = NULL; isn->is_sti.tqe_ifq = NULL; isn->is_sti.tqe_parent = isn; isn->is_ifp[0] = NULL; isn->is_ifp[1] = NULL; isn->is_ifp[2] = NULL; isn->is_ifp[3] = NULL; isn->is_sync = NULL; fr = ips.ips_rule; if (fr == NULL) { READ_ENTER(&ipf_state); fr_stinsert(isn, 0); RWLOCK_EXIT(&ipf_state); return 0; } if (isn->is_flags & SI_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; MUTEX_NUKE(&fr->fr_lock); MUTEX_INIT(&fr->fr_lock, "state filter rule lock"); /* * Look up all the interface names in the rule. */ for (i = 0; i < 4; i++) { name = fr->fr_ifnames[i]; fr->fr_ifas[i] = fr_resolvenic(name, fr->fr_v); name = isn->is_ifname[i]; isn->is_ifp[i] = fr_resolvenic(name, isn->is_v); } fr->fr_ref = 0; fr->fr_dsize = 0; fr->fr_data = NULL; fr_resolvedest(&fr->fr_tif, fr->fr_v); fr_resolvedest(&fr->fr_dif, fr->fr_v); /* * send a copy back to userland of what we ended up * to allow for verification. */ error = fr_outobj(data, &ips, IPFOBJ_STATESAVE); if (error) { KFREE(isn); MUTEX_DESTROY(&fr->fr_lock); KFREE(fr); return EFAULT; } READ_ENTER(&ipf_state); fr_stinsert(isn, 0); RWLOCK_EXIT(&ipf_state); } else { READ_ENTER(&ipf_state); for (is = ips_list; is; is = is->is_next) if (is->is_rule == fr) { fr_stinsert(isn, 0); break; } if (is == NULL) { KFREE(isn); isn = NULL; } RWLOCK_EXIT(&ipf_state); return (isn == NULL) ? ESRCH : 0; } return 0; } /* ------------------------------------------------------------------------ */ /* Function: fr_stinsert */ /* Returns: Nil */ /* Parameters: is(I) - pointer to state structure */ /* rev(I) - flag indicating forward/reverse direction of packet */ /* */ /* Inserts a state structure into the hash table (for lookups) and the list */ /* of state entries (for enumeration). Resolves all of the interface names */ /* to pointers and adjusts running stats for the hash table as appropriate. */ /* */ /* Locking: it is assumed that some kind of lock on ipf_state is held. */ /* ------------------------------------------------------------------------ */ void fr_stinsert(is, rev) ipstate_t *is; int rev; { frentry_t *fr; u_int hv; int i; MUTEX_INIT(&is->is_lock, "ipf state entry"); fr = is->is_rule; if (fr != NULL) { MUTEX_ENTER(&fr->fr_lock); fr->fr_ref++; fr->fr_statecnt++; MUTEX_EXIT(&fr->fr_lock); } /* * Look up all the interface names in the state entry. */ for (i = 0; i < 4; i++) { if (is->is_ifp[i] != NULL) continue; is->is_ifp[i] = fr_resolvenic(is->is_ifname[i], is->is_v); } /* * If we could trust is_hv, then the modulous would not be needed, but * when running with IPFILTER_SYNC, this stops bad values. */ hv = is->is_hv % fr_statesize; is->is_hv = hv; /* * We need to get both of these locks...the first because it is * possible that once the insert is complete another packet might * come along, match the entry and want to update it. */ MUTEX_ENTER(&is->is_lock); MUTEX_ENTER(&ipf_stinsert); /* * add into list table. */ if (ips_list != NULL) ips_list->is_pnext = &is->is_next; is->is_pnext = &ips_list; is->is_next = ips_list; ips_list = is; if (ips_table[hv] != NULL) 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_stats.iss_bucketlen[hv]++; ips_num++; MUTEX_EXIT(&ipf_stinsert); fr_setstatequeue(is, rev); MUTEX_EXIT(&is->is_lock); } /* ------------------------------------------------------------------------ */ /* Function: fr_addstate */ /* Returns: ipstate_t* - NULL == failure, else pointer to new state */ /* Parameters: fin(I) - pointer to packet information */ /* stsave(O) - pointer to place to save pointer to created */ /* state structure. */ /* flags(I) - flags to use when creating the structure */ /* */ /* Creates a new IP state structure from the packet information collected. */ /* Inserts it into the state table and appends to the bottom of the active */ /* list. If the capacity of the table has reached the maximum allowed then */ /* the call will fail and a flush is scheduled for the next timeout call. */ /* ------------------------------------------------------------------------ */ ipstate_t *fr_addstate(fin, stsave, flags) fr_info_t *fin; ipstate_t **stsave; u_int flags; { ipstate_t *is, ips; struct icmp *ic; u_int pass, hv; frentry_t *fr; tcphdr_t *tcp; grehdr_t *gre; void *ifp; int out; if (fr_state_lock || (fin->fin_flx & (FI_SHORT|FI_STATE|FI_FRAGBODY|FI_BAD))) return NULL; if ((fin->fin_flx & FI_OOW) && !(fin->fin_tcpf & TH_SYN)) return NULL; fr = fin->fin_fr; if ((fr->fr_statemax == 0) && (ips_num == fr_statemax)) { ATOMIC_INCL(ips_stats.iss_max); fr_state_doflush = 1; return NULL; } /* * If a "keep state" rule has reached the maximum number of references * to it, then schedule an automatic flush in case we can clear out * some "dead old wood". */ if ((fr != NULL) && (fr->fr_statemax != 0) && (fr->fr_statecnt >= fr->fr_statemax)) { MUTEX_EXIT(&fr->fr_lock); ATOMIC_INCL(ips_stats.iss_maxref); fr_state_doflush = 1; return NULL; } pass = (fr == NULL) ? 0 : fr->fr_flags; ic = NULL; tcp = NULL; out = fin->fin_out; is = &ips; bzero((char *)is, sizeof(*is)); is->is_die = 1 + fr_ticks; /* * 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) { /* * For ICMPv6, we check to see if the destination address is * a multicast address. If it is, do not include it in the * calculation of the hash because the correct reply will come * back from a real address, not a multicast address. */ if ((is->is_p == IPPROTO_ICMPV6) && IN6_IS_ADDR_MULTICAST(&is->is_dst.in6)) { /* * So you can do keep state with neighbour discovery. * * Here we could use the address from the neighbour * solicit message to put in the state structure and * we could use that without a wildcard flag too... */ flags |= SI_W_DADDR; hv -= is->is_daddr; } else { hv += is->is_dst.i6[1]; hv += is->is_dst.i6[2]; hv += is->is_dst.i6[3]; } hv += is->is_src.i6[1]; hv += is->is_src.i6[2]; hv += is->is_src.i6[3]; } #endif switch (is->is_p) { #ifdef USE_INET6 case IPPROTO_ICMPV6 : ic = fin->fin_dp; switch (ic->icmp_type) { case ICMP6_ECHO_REQUEST : is->is_icmp.ici_type = ic->icmp_type; hv += (is->is_icmp.ici_id = ic->icmp_id); break; case ICMP6_MEMBERSHIP_QUERY : case ND_ROUTER_SOLICIT : case ND_NEIGHBOR_SOLICIT : case ICMP6_NI_QUERY : is->is_icmp.ici_type = ic->icmp_type; break; default : return NULL; } ATOMIC_INCL(ips_stats.iss_icmp); break; #endif case IPPROTO_ICMP : ic = fin->fin_dp; switch (ic->icmp_type) { case ICMP_ECHO : case ICMP_TSTAMP : case ICMP_IREQ : case ICMP_MASKREQ : is->is_icmp.ici_type = ic->icmp_type; hv += (is->is_icmp.ici_id = ic->icmp_id); break; default : return NULL; } ATOMIC_INCL(ips_stats.iss_icmp); break; case IPPROTO_GRE : gre = fin->fin_dp; is->is_gre.gs_flags = gre->gr_flags; is->is_gre.gs_ptype = gre->gr_ptype; if (GRE_REV(is->is_gre.gs_flags) == 1) { is->is_call[0] = fin->fin_data[0]; is->is_call[1] = fin->fin_data[1]; } break; case IPPROTO_TCP : tcp = 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_sport = htons(fin->fin_data[0]); is->is_dport = htons(fin->fin_data[1]); if ((flags & (SI_W_DPORT|SI_W_SPORT)) == 0) { hv += is->is_sport; hv += is->is_dport; } /* * If this is a real packet then initialise fields in the * state information structure from the TCP header information. */ is->is_maxdwin = 1; is->is_maxswin = ntohs(tcp->th_win); if (is->is_maxswin == 0) is->is_maxswin = 1; if ((fin->fin_flx & FI_IGNORE) == 0) { is->is_send = ntohl(tcp->th_seq) + fin->fin_dlen - (TCP_OFF(tcp) << 2) + ((tcp->th_flags & TH_SYN) ? 1 : 0) + ((tcp->th_flags & TH_FIN) ? 1 : 0); is->is_maxsend = is->is_send; /* * Window scale option is only present in * SYN/SYN-ACK packet. */ if ((tcp->th_flags & ~(TH_FIN|TH_ACK|TH_ECNALL)) == TH_SYN && (TCP_OFF(tcp) > (sizeof(tcphdr_t) >> 2))) { if (fr_tcpoptions(fin, tcp, &is->is_tcp.ts_data[0])) is->is_swinflags = TCP_WSCALE_SEEN| TCP_WSCALE_FIRST; } if ((fin->fin_out != 0) && (pass & FR_NEWISN) != 0) { fr_checknewisn(fin, is); fr_fixoutisn(fin, is); } if ((tcp->th_flags & TH_OPENING) == TH_SYN) flags |= IS_TCPFSM; else { is->is_maxdwin = is->is_maxswin * 2; is->is_dend = ntohl(tcp->th_ack); is->is_maxdend = ntohl(tcp->th_ack); is->is_maxdwin *= 2; } } /* * 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 = fin->fin_dp; is->is_sport = htons(fin->fin_data[0]); is->is_dport = htons(fin->fin_data[1]); if ((flags & (SI_W_DPORT|SI_W_SPORT)) == 0) { hv += tcp->th_dport; hv += tcp->th_sport; } ATOMIC_INCL(ips_stats.iss_udp); break; default : break; } hv = DOUBLE_HASH(hv); is->is_hv = hv; is->is_rule = fr; is->is_flags = flags & IS_INHERITED; /* * Look for identical state. */ for (is = ips_table[is->is_hv % fr_statesize]; is != NULL; is = is->is_hnext) { if (bcmp(&ips.is_src, &is->is_src, offsetof(struct ipstate, is_ps) - offsetof(struct ipstate, is_src)) == 0) break; } if (is != NULL) return NULL; if (ips_stats.iss_bucketlen[hv] >= fr_state_maxbucket) { ATOMIC_INCL(ips_stats.iss_bucketfull); return NULL; } KMALLOC(is, ipstate_t *); if (is == NULL) { ATOMIC_INCL(ips_stats.iss_nomem); return NULL; } bcopy((char *)&ips, (char *)is, sizeof(*is)); /* * Do not do the modulous here, it is done in fr_stinsert(). */ if (fr != NULL) { (void) strncpy(is->is_group, fr->fr_group, FR_GROUPLEN); if (fr->fr_age[0] != 0) { is->is_tqehead[0] = fr_addtimeoutqueue(&ips_utqe, fr->fr_age[0]); is->is_sti.tqe_flags |= TQE_RULEBASED; } if (fr->fr_age[1] != 0) { is->is_tqehead[1] = fr_addtimeoutqueue(&ips_utqe, fr->fr_age[1]); is->is_sti.tqe_flags |= TQE_RULEBASED; } is->is_tag = fr->fr_logtag; is->is_ifp[(out << 1) + 1] = fr->fr_ifas[1]; is->is_ifp[(1 - out) << 1] = fr->fr_ifas[2]; is->is_ifp[((1 - out) << 1) + 1] = fr->fr_ifas[3]; if (((ifp = fr->fr_ifas[1]) != NULL) && (ifp != (void *)-1)) { COPYIFNAME(ifp, is->is_ifname[(out << 1) + 1]); } if (((ifp = fr->fr_ifas[2]) != NULL) && (ifp != (void *)-1)) { COPYIFNAME(ifp, is->is_ifname[(1 - out) << 1]); } if (((ifp = fr->fr_ifas[3]) != NULL) && (ifp != (void *)-1)) { COPYIFNAME(ifp, is->is_ifname[((1 - out) << 1) + 1]); } } else { pass = fr_flags; is->is_tag = FR_NOLOGTAG; } is->is_ifp[out << 1] = fin->fin_ifp; if (fin->fin_ifp != NULL) { COPYIFNAME(fin->fin_ifp, is->is_ifname[out << 1]); } /* * It may seem strange to set is_ref to 2, but fr_check() will call * fr_statederef() after calling fr_addstate() and the idea is to * have it exist at the end of fr_check() with is_ref == 1. */ is->is_ref = 2; is->is_pass = pass; is->is_pkts[0] = 0, is->is_bytes[0] = 0; is->is_pkts[1] = 0, is->is_bytes[1] = 0; is->is_pkts[2] = 0, is->is_bytes[2] = 0; is->is_pkts[3] = 0, is->is_bytes[3] = 0; if ((fin->fin_flx & FI_IGNORE) == 0) { is->is_pkts[out] = 1; is->is_bytes[out] = fin->fin_plen; is->is_flx[out][0] = fin->fin_flx & FI_CMP; is->is_flx[out][0] &= ~FI_OOW; } if (pass & FR_STSTRICT) is->is_flags |= IS_STRICT; if (pass & FR_STATESYNC) is->is_flags |= IS_STATESYNC; /* * 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_v; is->is_opt = fin->fin_optmsk; is->is_optmsk = 0xffffffff; is->is_sec = fin->fin_secmsk; is->is_secmsk = 0xffff; is->is_auth = fin->fin_auth; is->is_authmsk = 0xffff; if (flags & (SI_WILDP|SI_WILDA)) { ATOMIC_INCL(ips_stats.iss_wild); } is->is_rulen = fin->fin_rule; if (pass & FR_LOGFIRST) is->is_pass &= ~(FR_LOGFIRST|FR_LOG); READ_ENTER(&ipf_state); is->is_me = stsave; fr_stinsert(is, fin->fin_rev); if (fin->fin_p == IPPROTO_TCP) { /* * 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(&is->is_lock); (void) fr_tcp_age(&is->is_sti, fin, ips_tqtqb, is->is_flags); MUTEX_EXIT(&is->is_lock); #ifdef IPFILTER_SCAN if ((is->is_flags & SI_CLONE) == 0) (void) ipsc_attachis(is); #endif } #ifdef IPFILTER_SYNC if ((is->is_flags & IS_STATESYNC) && ((is->is_flags & SI_CLONE) == 0)) is->is_sync = ipfsync_new(SMC_STATE, fin, is); #endif if (ipstate_logging) ipstate_log(is, ISL_NEW); RWLOCK_EXIT(&ipf_state); fin->fin_state = is; fin->fin_rev = IP6_NEQ(&is->is_dst, &fin->fin_daddr); fin->fin_flx |= FI_STATE; if (fin->fin_flx & FI_FRAG) (void) fr_newfrag(fin, pass ^ FR_KEEPSTATE); return is; } /* ------------------------------------------------------------------------ */ /* Function: fr_tcpoptions */ /* Returns: int - 1 == packet matches state entry, 0 == it does not */ /* Parameters: fin(I) - pointer to packet information */ /* tcp(I) - pointer to TCP packet header */ /* td(I) - pointer to TCP data held as part of the state */ /* */ /* Look after the TCP header for any options and deal with those that are */ /* present. Record details about those that we recogise. */ /* ------------------------------------------------------------------------ */ static int fr_tcpoptions(fin, tcp, td) fr_info_t *fin; tcphdr_t *tcp; tcpdata_t *td; { int off, mlen, ol, i, len, retval; char buf[64], *s, opt; mb_t *m = NULL; off = fin->fin_hlen + sizeof(*tcp); len = (TCP_OFF(tcp) << 2) - sizeof(*tcp); if (fin->fin_plen < off + len) return 0; m = fin->fin_m; off += fin->fin_ipoff; mlen = MSGDSIZE(m) - off; if (len > mlen) { len = mlen; retval = 0; } else { retval = 1; } COPYDATA(m, off, len, buf); for (s = buf; len > 0; ) { opt = *s; if (opt == TCPOPT_EOL) break; else if (opt == TCPOPT_NOP) ol = 1; else { if (len < 2) break; ol = (int)*(s + 1); if (ol < 2 || ol > len) break; /* * Extract the TCP options we are interested in out of * the header and store them in the the tcpdata struct. */ switch (opt) { case TCPOPT_WINDOW : if (ol == TCPOLEN_WINDOW) { i = (int)*(s + 2); if (i > TCP_WSCALE_MAX) i = TCP_WSCALE_MAX; else if (i < 0) i = 0; td->td_winscale = i; } break; case TCPOPT_MAXSEG : /* * So, if we wanted to set the TCP MAXSEG, * it should be done here... */ if (ol == TCPOLEN_MAXSEG) { i = (int)*(s + 2); i <<= 8; i += (int)*(s + 3); td->td_maxseg = i; } break; } } len -= ol; s += ol; } return retval; } /* ------------------------------------------------------------------------ */ /* Function: fr_tcpstate */ /* Returns: int - 1 == packet matches state entry, 0 == it does not */ /* Parameters: fin(I) - pointer to packet information */ /* tcp(I) - pointer to TCP packet header */ /* is(I) - pointer to master state structure */ /* */ /* 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. */ /* ------------------------------------------------------------------------ */ static int fr_tcpstate(fin, tcp, is) fr_info_t *fin; tcphdr_t *tcp; ipstate_t *is; { int source, ret = 0, flags; tcpdata_t *fdata, *tdata; source = !fin->fin_rev; if (((is->is_flags & IS_TCPFSM) != 0) && (source == 1) && (ntohs(is->is_sport) != fin->fin_data[0])) source = 0; fdata = &is->is_tcp.ts_data[!source]; tdata = &is->is_tcp.ts_data[source]; MUTEX_ENTER(&is->is_lock); if (fr_tcpinwindow(fin, fdata, tdata, tcp, is->is_flags)) { #ifdef IPFILTER_SCAN if (is->is_flags & (IS_SC_CLIENT|IS_SC_SERVER)) { ipsc_packet(fin, is); if (FR_ISBLOCK(is->is_pass)) { MUTEX_EXIT(&is->is_lock); return 1; } } #endif /* * Nearing end of connection, start timeout. */ ret = fr_tcp_age(&is->is_sti, fin, ips_tqtqb, is->is_flags); if (ret == 0) { MUTEX_EXIT(&is->is_lock); return 0; } /* * set s0's as appropriate. Use syn-ack packet as it * contains both pieces of required information. */ /* * Window scale option is only present in SYN/SYN-ACK packet. * Compare with ~TH_FIN to mask out T/TCP setups. */ flags = tcp->th_flags & ~(TH_FIN|TH_ECNALL); if (flags == (TH_SYN|TH_ACK)) { is->is_s0[source] = ntohl(tcp->th_ack); is->is_s0[!source] = ntohl(tcp->th_seq) + 1; if ((TCP_OFF(tcp) > (sizeof(tcphdr_t) >> 2)) && tdata->td_winscale) { if (fr_tcpoptions(fin, tcp, fdata)) { fdata->td_winflags = TCP_WSCALE_SEEN| TCP_WSCALE_FIRST; } else { if (!fdata->td_winscale) tdata->td_winscale = 0; } } if ((fin->fin_out != 0) && (is->is_pass & FR_NEWISN)) fr_checknewisn(fin, is); } else if (flags == TH_SYN) { is->is_s0[source] = ntohl(tcp->th_seq) + 1; if ((TCP_OFF(tcp) > (sizeof(tcphdr_t) >> 2))) if (fr_tcpoptions(fin, tcp, tdata)) { tdata->td_winflags = TCP_WSCALE_SEEN| TCP_WSCALE_FIRST; } if ((fin->fin_out != 0) && (is->is_pass & FR_NEWISN)) fr_checknewisn(fin, is); } ret = 1; } else fin->fin_flx |= FI_OOW; MUTEX_EXIT(&is->is_lock); return ret; } /* ------------------------------------------------------------------------ */ /* Function: fr_checknewisn */ /* Returns: Nil */ /* Parameters: fin(I) - pointer to packet information */ /* is(I) - pointer to master state structure */ /* */ /* Check to see if this TCP connection is expecting and needs a new */ /* sequence number for a particular direction of the connection. */ /* */ /* NOTE: This does not actually change the sequence numbers, only gets new */ /* one ready. */ /* ------------------------------------------------------------------------ */ static void fr_checknewisn(fin, is) fr_info_t *fin; ipstate_t *is; { u_32_t sumd, old, new; tcphdr_t *tcp; int i; i = fin->fin_rev; tcp = fin->fin_dp; if (((i == 0) && !(is->is_flags & IS_ISNSYN)) || ((i == 1) && !(is->is_flags & IS_ISNACK))) { old = ntohl(tcp->th_seq); new = fr_newisn(fin); is->is_isninc[i] = new - old; CALC_SUMD(old, new, sumd); is->is_sumd[i] = (sumd & 0xffff) + (sumd >> 16); is->is_flags |= ((i == 0) ? IS_ISNSYN : IS_ISNACK); } } /* ------------------------------------------------------------------------ */ /* Function: fr_tcpinwindow */ /* Returns: int - 1 == packet inside TCP "window", 0 == not inside. */ /* Parameters: fin(I) - pointer to packet information */ /* fdata(I) - pointer to tcp state informatio (forward) */ /* tdata(I) - pointer to tcp state informatio (reverse) */ /* tcp(I) - pointer to TCP packet header */ /* */ /* Given a packet has matched addresses and ports, check to see if it is */ /* within the TCP data window. In a show of generosity, allow packets that */ /* are within the window space behind the current sequence # as well. */ /* ------------------------------------------------------------------------ */ int fr_tcpinwindow(fin, fdata, tdata, tcp, flags) fr_info_t *fin; tcpdata_t *fdata, *tdata; tcphdr_t *tcp; int flags; { #ifdef BROKEN_TCP_WINDOW_CHECK tcp_seq seq, ack, end; int ackskew, tcpflags; u_32_t win, maxwin; /* * Find difference between last checked packet and this packet. */ tcpflags = tcp->th_flags; seq = ntohl(tcp->th_seq); ack = ntohl(tcp->th_ack); if (tcpflags & TH_SYN) win = ntohs(tcp->th_win); else win = ntohs(tcp->th_win) << fdata->td_winscale; if (win == 0) win = 1; /* * if window scaling is present, the scaling is only allowed * for windows not in the first SYN packet. In that packet the * window is 65535 to specify the largest window possible * for receivers not implementing the window scale option. * Currently, we do not assume TTCP here. That means that * if we see a second packet from a host (after the initial * SYN), we can assume that the receiver of the SYN did * already send back the SYN/ACK (and thus that we know if * the receiver also does window scaling) */ if (!(tcpflags & TH_SYN) && (fdata->td_winflags & TCP_WSCALE_FIRST)) { if (tdata->td_winflags & TCP_WSCALE_SEEN) { fdata->td_winflags &= ~TCP_WSCALE_FIRST; fdata->td_maxwin = win; } else { fdata->td_winscale = 0; fdata->td_winflags = 0; tdata->td_winscale = 0; tdata->td_winflags = 0; } } end = seq + fin->fin_dlen - (TCP_OFF(tcp) << 2) + ((tcpflags & TH_SYN) ? 1 : 0) + ((tcpflags & TH_FIN) ? 1 : 0); if ((fdata->td_end == 0) && (!(flags & IS_TCPFSM) || ((tcpflags & TH_OPENING) == TH_OPENING))) { /* * Must be a (outgoing) SYN-ACK in reply to a SYN. */ fdata->td_end = end; fdata->td_maxwin = 1; fdata->td_maxend = end + win; } if (!(tcpflags & TH_ACK)) { /* Pretend an ack was sent */ ack = tdata->td_end; } else if (((tcpflags & (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; /* * Strict sequencing only allows in-order delivery. */ if ((flags & IS_STRICT) != 0) { if (seq != fdata->td_end) { return 0; } } #define SEQ_GE(a,b) ((int)((a) - (b)) >= 0) #define SEQ_GT(a,b) ((int)((a) - (b)) > 0) if ( #if defined(_KERNEL) (SEQ_GE(fdata->td_maxend, end)) && (SEQ_GE(seq, fdata->td_end - maxwin)) && #endif /* XXX what about big packets */ #define MAXACKWINDOW 66000 (-ackskew <= (MAXACKWINDOW << fdata->td_winscale)) && ( ackskew <= (MAXACKWINDOW << fdata->td_winscale))) { /* if ackskew < 0 then this should be due to fragmented * 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 parameters 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; return 1; } return 0; #else return 1; #endif } /* ------------------------------------------------------------------------ */ /* Function: fr_stclone */ /* Returns: ipstate_t* - NULL == cloning failed, */ /* else pointer to new state structure */ /* Parameters: fin(I) - pointer to packet information */ /* tcp(I) - pointer to TCP/UDP header */ /* is(I) - pointer to master state structure */ /* */ /* Create a "duplcate" state table entry from the master. */ /* ------------------------------------------------------------------------ */ static ipstate_t *fr_stclone(fin, tcp, is) fr_info_t *fin; tcphdr_t *tcp; ipstate_t *is; { ipstate_t *clone; u_32_t send; if (ips_num == fr_statemax) { ATOMIC_INCL(ips_stats.iss_max); fr_state_doflush = 1; return NULL; } KMALLOC(clone, ipstate_t *); if (clone == NULL) return NULL; bcopy((char *)is, (char *)clone, sizeof(*clone)); MUTEX_NUKE(&clone->is_lock); clone->is_die = ONE_DAY + fr_ticks; clone->is_state[0] = 0; clone->is_state[1] = 0; send = ntohl(tcp->th_seq) + fin->fin_dlen - (TCP_OFF(tcp) << 2) + ((tcp->th_flags & TH_SYN) ? 1 : 0) + ((tcp->th_flags & TH_FIN) ? 1 : 0); if (fin->fin_rev == 1) { clone->is_dend = send; clone->is_maxdend = send; clone->is_send = 0; clone->is_maxswin = 1; clone->is_maxdwin = ntohs(tcp->th_win); if (clone->is_maxdwin == 0) clone->is_maxdwin = 1; } else { clone->is_send = send; clone->is_maxsend = send; clone->is_dend = 0; clone->is_maxdwin = 1; clone->is_maxswin = ntohs(tcp->th_win); if (clone->is_maxswin == 0) clone->is_maxswin = 1; } clone->is_flags &= ~SI_CLONE; clone->is_flags |= SI_CLONED; fr_stinsert(clone, fin->fin_rev); MUTEX_ENTER(&clone->is_lock); clone->is_ref = 1; if (clone->is_p == IPPROTO_TCP) { (void) fr_tcp_age(&clone->is_sti, fin, ips_tqtqb, clone->is_flags); } MUTEX_EXIT(&clone->is_lock); #ifdef IPFILTER_SCAN (void) ipsc_attachis(is); #endif #ifdef IPFILTER_SYNC if (is->is_flags & IS_STATESYNC) clone->is_sync = ipfsync_new(SMC_STATE, fin, clone); #endif return clone; } /* ------------------------------------------------------------------------ */ /* Function: fr_matchsrcdst */ /* Returns: Nil */ /* Parameters: fin(I) - pointer to packet information */ /* is(I) - pointer to state structure */ /* src(I) - pointer to source address */ /* dst(I) - pointer to destination address */ /* tcp(I) - pointer to TCP/UDP header */ /* */ /* Match a state table entry against an IP packet. The logic below is that */ /* ret gets set to one if the match succeeds, else remains 0. If it is */ /* still 0 after the test. no match. */ /* ------------------------------------------------------------------------ */ static ipstate_t *fr_matchsrcdst(fin, is, src, dst, tcp, cmask) fr_info_t *fin; ipstate_t *is; i6addr_t *src, *dst; tcphdr_t *tcp; u_32_t cmask; { int ret = 0, rev, out, flags, flx = 0, idx; u_short sp, dp; u_32_t cflx; void *ifp; rev = IP6_NEQ(&is->is_dst, dst); ifp = fin->fin_ifp; out = fin->fin_out; flags = is->is_flags; sp = 0; dp = 0; if (tcp != NULL) { sp = htons(fin->fin_sport); dp = ntohs(fin->fin_dport); } if (!rev) { if (tcp != NULL) { if (!(flags & SI_W_SPORT) && (sp != is->is_sport)) rev = 1; else if (!(flags & SI_W_DPORT) && (dp != is->is_dport)) rev = 1; } } idx = (out << 1) + rev; /* * If the interface for this 'direction' is set, make sure it matches. * An interface name that is not set matches any, as does a name of *. */ if ((is->is_ifp[idx] == NULL && (*is->is_ifname[idx] == '\0' || *is->is_ifname[idx] == '*')) || is->is_ifp[idx] == ifp) ret = 1; if (ret == 0) return NULL; ret = 0; /* * Match addresses and ports. */ if (rev == 0) { if ((IP6_EQ(&is->is_dst, dst) || (flags & SI_W_DADDR)) && (IP6_EQ(&is->is_src, src) || (flags & SI_W_SADDR))) { if (tcp) { if ((sp == is->is_sport || flags & SI_W_SPORT)&& (dp == is->is_dport || flags & SI_W_DPORT)) ret = 1; } else { ret = 1; } } } else { if ((IP6_EQ(&is->is_dst, src) || (flags & SI_W_DADDR)) && (IP6_EQ(&is->is_src, dst) || (flags & SI_W_SADDR))) { if (tcp) { if ((dp == is->is_sport || flags & SI_W_SPORT)&& (sp == is->is_dport || flags & SI_W_DPORT)) ret = 1; } else { ret = 1; } } } if (ret == 0) return NULL; /* * 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 & ~(SI_WILDP|SI_NEWFR|SI_CLONE|SI_CLONED); /* * Only one of the source or destination address can be flaged as a * wildcard. Fill in the missing address, if set. * For IPv6, if the address being copied in is multicast, then * don't reset the wild flag - multicast causes it to be set in the * first place! */ if ((flags & (SI_W_SADDR|SI_W_DADDR))) { fr_ip_t *fi = &fin->fin_fi; if ((flags & SI_W_SADDR) != 0) { if (rev == 0) { #ifdef USE_INET6 if (is->is_v == 6 && IN6_IS_ADDR_MULTICAST(&fi->fi_src.in6)) /*EMPTY*/; else #endif { is->is_src = fi->fi_src; is->is_flags &= ~SI_W_SADDR; } } else { #ifdef USE_INET6 if (is->is_v == 6 && IN6_IS_ADDR_MULTICAST(&fi->fi_dst.in6)) /*EMPTY*/; else #endif { is->is_src = fi->fi_dst; is->is_flags &= ~SI_W_SADDR; } } } else if ((flags & SI_W_DADDR) != 0) { if (rev == 0) { #ifdef USE_INET6 if (is->is_v == 6 && IN6_IS_ADDR_MULTICAST(&fi->fi_dst.in6)) /*EMPTY*/; else #endif { is->is_dst = fi->fi_dst; is->is_flags &= ~SI_W_DADDR; } } else { #ifdef USE_INET6 if (is->is_v == 6 && IN6_IS_ADDR_MULTICAST(&fi->fi_src.in6)) /*EMPTY*/; else #endif { is->is_dst = fi->fi_src; is->is_flags &= ~SI_W_DADDR; } } } if ((is->is_flags & (SI_WILDA|SI_WILDP)) == 0) { ATOMIC_DECL(ips_stats.iss_wild); } } flx = fin->fin_flx & cmask; cflx = is->is_flx[out][rev]; /* * Match up any flags set from IP options. */ if ((cflx && (flx != (cflx & cmask))) || ((fin->fin_optmsk & is->is_optmsk) != is->is_opt) || ((fin->fin_secmsk & is->is_secmsk) != is->is_sec) || ((fin->fin_auth & is->is_authmsk) != is->is_auth)) return NULL; /* * Only one of the source or destination port can be flagged as a * wildcard. When filling it in, fill in a copy of the matched entry * if it has the cloning flag set. */ if ((fin->fin_flx & FI_IGNORE) != 0) { fin->fin_rev = rev; return is; } if ((flags & (SI_W_SPORT|SI_W_DPORT))) { if ((flags & SI_CLONE) != 0) { is = fr_stclone(fin, tcp, is); if (is == NULL) return NULL; } else { ATOMIC_DECL(ips_stats.iss_wild); } if ((flags & SI_W_SPORT) != 0) { if (rev == 0) { is->is_sport = sp; is->is_send = ntohl(tcp->th_seq); } else { is->is_sport = dp; is->is_send = ntohl(tcp->th_ack); } is->is_maxsend = is->is_send + 1; } else if ((flags & SI_W_DPORT) != 0) { if (rev == 0) { is->is_dport = dp; is->is_dend = ntohl(tcp->th_ack); } else { is->is_dport = sp; is->is_dend = ntohl(tcp->th_seq); } is->is_maxdend = is->is_dend + 1; } is->is_flags &= ~(SI_W_SPORT|SI_W_DPORT); if ((flags & SI_CLONED) && ipstate_logging) ipstate_log(is, ISL_CLONE); } ret = -1; if (is->is_flx[out][rev] == 0) is->is_flx[out][rev] = flx; /* * Check if the interface name for this "direction" is set and if not, * fill it in. */ if (is->is_ifp[idx] == NULL && (*is->is_ifname[idx] == '\0' || *is->is_ifname[idx] == '*')) { is->is_ifp[idx] = ifp; COPYIFNAME(ifp, is->is_ifname[idx]); } fin->fin_rev = rev; return is; } /* ------------------------------------------------------------------------ */ /* Function: fr_checkicmpmatchingstate */ /* Returns: Nil */ /* Parameters: fin(I) - pointer to packet information */ /* */ /* If we've got an ICMP error message, using the information stored in the */ /* ICMP packet, look for a matching state table entry. */ /* */ /* If we return NULL then no lock on ipf_state is held. */ /* If we return non-null then a read-lock on ipf_state is held. */ /* ------------------------------------------------------------------------ */ static ipstate_t *fr_checkicmpmatchingstate(fin) fr_info_t *fin; { ipstate_t *is, **isp; u_short sport, dport; u_char pr; int backward, i, oi; i6addr_t dst, src; struct icmp *ic; u_short savelen; icmphdr_t *icmp; fr_info_t ofin; tcphdr_t *tcp; int type, len; 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 ((fin->fin_v != 4) || (fin->fin_hlen != sizeof(ip_t)) || (fin->fin_plen < ICMPERR_MINPKTLEN)) return NULL; ic = 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); /* * Check if the at least the old IP header (with options) and * 8 bytes of payload is present. */ if (fin->fin_plen < ICMPERR_MAXPKTLEN + ((IP_HL(oip) - 5) << 2)) return NULL; /* * Sanity Checks. */ len = fin->fin_dlen - ICMPERR_ICMPHLEN; if ((len <= 0) || ((IP_HL(oip) << 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 guarantee it is * all here now. */ #ifdef _KERNEL { mb_t *m; m = fin->fin_m; # if defined(MENTAT) if ((char *)oip + len > (char *)m->b_wptr) return NULL; # else if ((char *)oip + len > (char *)fin->fin_ip + m->m_len) return NULL; # endif } #endif bcopy((char *)fin, (char *)&ofin, sizeof(fin)); /* * in the IPv4 case we must zero the i6addr union otherwise * the IP6_EQ and IP6_NEQ 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)); /* * 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, like * oip->ip_off - it is still in network byte order so fix it. */ savelen = oip->ip_len; oip->ip_len = len; oip->ip_off = htons(oip->ip_off); ofin.fin_flx = FI_NOCKSUM; ofin.fin_v = 4; ofin.fin_ip = oip; ofin.fin_m = NULL; /* if dereferenced, panic XXX */ ofin.fin_mp = NULL; /* if dereferenced, panic XXX */ ofin.fin_plen = fin->fin_dlen - ICMPERR_ICMPHLEN; (void) fr_makefrip(IP_HL(oip) << 2, oip, &ofin); ofin.fin_ifp = fin->fin_ifp; ofin.fin_out = !fin->fin_out; /* * Reset the short and bad flag here because in fr_matchsrcdst() * the flags for the current packet (fin_flx) are compared against * those for the existing session. */ ofin.fin_flx &= ~(FI_BAD|FI_SHORT); /* * Put old values of ip_len and ip_off back as we don't know * if we have to forward the packet (or process it again. */ oip->ip_len = savelen; oip->ip_off = htons(oip->ip_off); switch (oip->ip_p) { case IPPROTO_ICMP : icmp = (icmphdr_t *)((char *)oip + (IP_HL(oip) << 2)); /* * an 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 = DOUBLE_HASH(hv); READ_ENTER(&ipf_state); for (isp = &ips_table[hv]; ((is = *isp) != NULL); ) { isp = &is->is_hnext; if ((is->is_p != pr) || (is->is_v != 4)) continue; if (is->is_pass & FR_NOICMPERR) continue; is = fr_matchsrcdst(&ofin, is, &src, &dst, NULL, FI_ICMPCMP); if (is != NULL) { if ((is->is_pass & FR_NOICMPERR) != 0) { RWLOCK_EXIT(&ipf_state); return NULL; } /* * i : the index of this packet (the icmp * unreachable) * oi : the index of the original packet found * in the icmp header (i.e. the packet * causing this icmp) * backward : original packet was backward * compared to the state */ backward = IP6_NEQ(&is->is_src, &src); fin->fin_rev = !backward; i = (!backward << 1) + fin->fin_out; oi = (backward << 1) + ofin.fin_out; if (is->is_icmppkts[i] > is->is_pkts[oi]) continue; ips_stats.iss_hits++; is->is_icmppkts[i]++; return is; } } RWLOCK_EXIT(&ipf_state); return NULL; case IPPROTO_TCP : case IPPROTO_UDP : break; default : return NULL; } tcp = (tcphdr_t *)((char *)oip + (IP_HL(oip) << 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 = DOUBLE_HASH(hv); READ_ENTER(&ipf_state); for (isp = &ips_table[hv]; ((is = *isp) != NULL); ) { 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. Only the * ports are known to be present and can be even if the * short flag is set. */ if ((is->is_p == pr) && (is->is_v == 4) && (is = fr_matchsrcdst(&ofin, is, &src, &dst, tcp, FI_ICMPCMP))) { /* * i : the index of this packet (the icmp unreachable) * oi : the index of the original packet found in the * icmp header (i.e. the packet causing this icmp) * backward : original packet was backward compared to * the state */ backward = IP6_NEQ(&is->is_src, &src); fin->fin_rev = !backward; i = (!backward << 1) + fin->fin_out; oi = (backward << 1) + ofin.fin_out; if (((is->is_pass & FR_NOICMPERR) != 0) || (is->is_icmppkts[i] > is->is_pkts[oi])) break; ips_stats.iss_hits++; is->is_icmppkts[i]++; /* * we deliberately do not touch the timeouts * for the accompanying state table entry. * It remains to be seen if that is correct. XXX */ return is; } } RWLOCK_EXIT(&ipf_state); return NULL; } /* ------------------------------------------------------------------------ */ /* Function: fr_ipsmove */ /* Returns: Nil */ /* Parameters: is(I) - pointer to state table entry */ /* hv(I) - new hash value for state table entry */ /* Write Locks: ipf_state */ /* */ /* Move a state entry from one position in the hash table to another. */ /* ------------------------------------------------------------------------ */ static void fr_ipsmove(is, hv) ipstate_t *is; u_int hv; { ipstate_t **isp; u_int hvm; ASSERT(rw_read_locked(&ipf_state.ipf_lk) == 0); hvm = is->is_hv; /* * Remove the hash from the old location... */ isp = is->is_phnext; if (is->is_hnext) is->is_hnext->is_phnext = isp; *isp = is->is_hnext; if (ips_table[hvm] == NULL) ips_stats.iss_inuse--; ips_stats.iss_bucketlen[hvm]--; /* * ...and put the hash in the new one. */ hvm = DOUBLE_HASH(hv); is->is_hv = hvm; isp = &ips_table[hvm]; if (*isp) (*isp)->is_phnext = &is->is_hnext; else ips_stats.iss_inuse++; ips_stats.iss_bucketlen[hvm]++; is->is_phnext = isp; is->is_hnext = *isp; *isp = is; } /* ------------------------------------------------------------------------ */ /* Function: fr_stlookup */ /* Returns: ipstate_t* - NULL == no matching state found, */ /* else pointer to state information is returned */ /* Parameters: fin(I) - pointer to packet information */ /* tcp(I) - pointer to TCP/UDP header. */ /* */ /* Search the state table for a matching entry to the packet described by */ /* the contents of *fin. */ /* */ /* If we return NULL then no lock on ipf_state is held. */ /* If we return non-null then a read-lock on ipf_state is held. */ /* ------------------------------------------------------------------------ */ ipstate_t *fr_stlookup(fin, tcp, ifqp) fr_info_t *fin; tcphdr_t *tcp; ipftq_t **ifqp; { u_int hv, hvm, pr, v, tryagain; ipstate_t *is, **isp; u_short dport, sport; i6addr_t src, dst; struct icmp *ic; ipftq_t *ifq; int oow; is = NULL; ifq = NULL; tcp = fin->fin_dp; 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; v = fin->fin_fi.fi_v; #ifdef USE_INET6 if (v == 6) { hv += fin->fin_fi.fi_src.i6[1]; hv += fin->fin_fi.fi_src.i6[2]; hv += fin->fin_fi.fi_src.i6[3]; if ((fin->fin_p == IPPROTO_ICMPV6) && IN6_IS_ADDR_MULTICAST(&fin->fin_fi.fi_dst.in6)) { hv -= dst.in4.s_addr; } else { hv += fin->fin_fi.fi_dst.i6[1]; hv += fin->fin_fi.fi_dst.i6[2]; hv += fin->fin_fi.fi_dst.i6[3]; } } #endif /* * Search the hash table for matching packet header info. */ switch (pr) { #ifdef USE_INET6 case IPPROTO_ICMPV6 : tryagain = 0; if (v == 6) { if ((ic->icmp_type == ICMP6_ECHO_REQUEST) || (ic->icmp_type == ICMP6_ECHO_REPLY)) { hv += ic->icmp_id; } } READ_ENTER(&ipf_state); icmp6again: hvm = DOUBLE_HASH(hv); for (isp = &ips_table[hvm]; ((is = *isp) != NULL); ) { isp = &is->is_hnext; if ((is->is_p != pr) || (is->is_v != v)) continue; is = fr_matchsrcdst(fin, is, &src, &dst, NULL, FI_CMP); if (is != NULL && fr_matchicmpqueryreply(v, &is->is_icmp, ic, fin->fin_rev)) { if (fin->fin_rev) ifq = &ips_icmpacktq; else ifq = &ips_icmptq; break; } } if (is != NULL) { if ((tryagain != 0) && !(is->is_flags & SI_W_DADDR)) { hv += fin->fin_fi.fi_src.i6[0]; hv += fin->fin_fi.fi_src.i6[1]; hv += fin->fin_fi.fi_src.i6[2]; hv += fin->fin_fi.fi_src.i6[3]; fr_ipsmove(is, hv); MUTEX_DOWNGRADE(&ipf_state); } break; } RWLOCK_EXIT(&ipf_state); /* * No matching icmp state entry. Perhaps this is a * response to another state entry. * * XXX With some ICMP6 packets, the "other" address is already * in the packet, after the ICMP6 header, and this could be * used in place of the multicast address. However, taking * advantage of this requires some significant code changes * to handle the specific types where that is the case. */ if ((ips_stats.iss_wild != 0) && (v == 6) && (tryagain == 0) && !IN6_IS_ADDR_MULTICAST(&fin->fin_fi.fi_src.in6)) { hv -= fin->fin_fi.fi_src.i6[0]; hv -= fin->fin_fi.fi_src.i6[1]; hv -= fin->fin_fi.fi_src.i6[2]; hv -= fin->fin_fi.fi_src.i6[3]; tryagain = 1; WRITE_ENTER(&ipf_state); goto icmp6again; } is = fr_checkicmp6matchingstate(fin); if (is != NULL) return is; break; #endif case IPPROTO_ICMP : if (v == 4) { hv += ic->icmp_id; } hv = DOUBLE_HASH(hv); READ_ENTER(&ipf_state); for (isp = &ips_table[hv]; ((is = *isp) != NULL); ) { isp = &is->is_hnext; if ((is->is_p != pr) || (is->is_v != v)) continue; is = fr_matchsrcdst(fin, is, &src, &dst, NULL, FI_CMP); if (is != NULL && fr_matchicmpqueryreply(v, &is->is_icmp, ic, fin->fin_rev)) { if (fin->fin_rev) ifq = &ips_icmpacktq; else ifq = &ips_icmptq; break; } } if (is == NULL) { RWLOCK_EXIT(&ipf_state); } break; case IPPROTO_TCP : case IPPROTO_UDP : ifqp = NULL; sport = htons(fin->fin_data[0]); hv += sport; dport = htons(fin->fin_data[1]); hv += dport; oow = 0; tryagain = 0; READ_ENTER(&ipf_state); retry_tcpudp: hvm = DOUBLE_HASH(hv); for (isp = &ips_table[hvm]; ((is = *isp) != NULL); ) { isp = &is->is_hnext; if ((is->is_p != pr) || (is->is_v != v)) continue; fin->fin_flx &= ~FI_OOW; is = fr_matchsrcdst(fin, is, &src, &dst, tcp, FI_CMP); if (is != NULL) { if (pr == IPPROTO_TCP) { if (!fr_tcpstate(fin, tcp, is)) { oow |= fin->fin_flx & FI_OOW; continue; } } break; } } if (is != NULL) { if (tryagain && !(is->is_flags & (SI_CLONE|SI_WILDP|SI_WILDA))) { hv += dport; hv += sport; fr_ipsmove(is, hv); MUTEX_DOWNGRADE(&ipf_state); } break; } RWLOCK_EXIT(&ipf_state); if (!tryagain && ips_stats.iss_wild) { hv -= dport; hv -= sport; tryagain = 1; WRITE_ENTER(&ipf_state); goto retry_tcpudp; } fin->fin_flx |= oow; break; #if 0 case IPPROTO_GRE : gre = fin->fin_dp; if (GRE_REV(gre->gr_flags) == 1) { hv += gre->gr_call; } /* FALLTHROUGH */ #endif default : ifqp = NULL; hvm = DOUBLE_HASH(hv); READ_ENTER(&ipf_state); for (isp = &ips_table[hvm]; ((is = *isp) != NULL); ) { isp = &is->is_hnext; if ((is->is_p != pr) || (is->is_v != v)) continue; is = fr_matchsrcdst(fin, is, &src, &dst, NULL, FI_CMP); if (is != NULL) { ifq = &ips_iptq; break; } } if (is == NULL) { RWLOCK_EXIT(&ipf_state); } break; } if ((is != NULL) && ((is->is_sti.tqe_flags & TQE_RULEBASED) != 0) && (is->is_tqehead[fin->fin_rev] != NULL)) ifq = is->is_tqehead[fin->fin_rev]; if (ifq != NULL && ifqp != NULL) *ifqp = ifq; return is; } /* ------------------------------------------------------------------------ */ /* Function: fr_updatestate */ /* Returns: Nil */ /* Parameters: fin(I) - pointer to packet information */ /* is(I) - pointer to state table entry */ /* Read Locks: ipf_state */ /* */ /* Updates packet and byte counters for a newly received packet. Seeds the */ /* fragment cache with a new entry as required. */ /* ------------------------------------------------------------------------ */ void fr_updatestate(fin, is, ifq) fr_info_t *fin; ipstate_t *is; ipftq_t *ifq; { ipftqent_t *tqe; int i, pass; i = (fin->fin_rev << 1) + fin->fin_out; /* * For TCP packets, ifq == NULL. For all others, check if this new * queue is different to the last one it was on and move it if so. */ tqe = &is->is_sti; MUTEX_ENTER(&is->is_lock); if ((tqe->tqe_flags & TQE_RULEBASED) != 0) ifq = is->is_tqehead[fin->fin_rev]; if (ifq != NULL) fr_movequeue(tqe, tqe->tqe_ifq, ifq); is->is_pkts[i]++; is->is_bytes[i] += fin->fin_plen; MUTEX_EXIT(&is->is_lock); #ifdef IPFILTER_SYNC if (is->is_flags & IS_STATESYNC) ipfsync_update(SMC_STATE, fin, is->is_sync); #endif ATOMIC_INCL(ips_stats.iss_hits); fin->fin_fr = is->is_rule; /* * If this packet is a fragment and the rule says to track fragments, * then create a new fragment cache entry. */ pass = is->is_pass; if ((fin->fin_flx & FI_FRAG) && FR_ISPASS(pass)) (void) fr_newfrag(fin, pass ^ FR_KEEPSTATE); } /* ------------------------------------------------------------------------ */ /* Function: fr_checkstate */ /* Returns: frentry_t* - NULL == search failed, */ /* else pointer to rule for matching state */ /* Parameters: ifp(I) - pointer to interface */ /* passp(I) - pointer to filtering result flags */ /* */ /* Check if a packet is associated with an entry in the state table. */ /* ------------------------------------------------------------------------ */ frentry_t *fr_checkstate(fin, passp) fr_info_t *fin; u_32_t *passp; { ipstate_t *is; frentry_t *fr; tcphdr_t *tcp; ipftq_t *ifq; u_int pass; if (fr_state_lock || (ips_list == NULL) || (fin->fin_flx & (FI_SHORT|FI_STATE|FI_FRAGBODY|FI_BAD))) return NULL; is = NULL; if ((fin->fin_flx & FI_TCPUDP) || (fin->fin_fi.fi_p == IPPROTO_ICMP) #ifdef USE_INET6 || (fin->fin_fi.fi_p == IPPROTO_ICMPV6) #endif ) tcp = fin->fin_dp; else tcp = NULL; /* * Search the hash table for matching packet header info. */ ifq = NULL; is = fin->fin_state; if (is == NULL) is = fr_stlookup(fin, tcp, &ifq); switch (fin->fin_p) { #ifdef USE_INET6 case IPPROTO_ICMPV6 : if (is != NULL) break; if (fin->fin_v == 6) { is = fr_checkicmp6matchingstate(fin); if (is != NULL) goto matched; } break; #endif case IPPROTO_ICMP : if (is != NULL) break; /* * No matching icmp state entry. Perhaps this is a * response to another state entry. */ is = fr_checkicmpmatchingstate(fin); if (is != NULL) goto matched; break; case IPPROTO_TCP : if (is == NULL) break; if (is->is_pass & FR_NEWISN) { if (fin->fin_out == 0) fr_fixinisn(fin, is); else if (fin->fin_out == 1) fr_fixoutisn(fin, is); } break; default : if (fin->fin_rev) ifq = &ips_udpacktq; else ifq = &ips_udptq; break; } if (is == NULL) { ATOMIC_INCL(ips_stats.iss_miss); return NULL; } matched: fr = is->is_rule; if (fr != NULL) { if ((fin->fin_out == 0) && (fr->fr_nattag.ipt_num[0] != 0)) { if (fin->fin_nattag == NULL) return NULL; if (fr_matchtag(&fr->fr_nattag, fin->fin_nattag) != 0) return NULL; } (void) strncpy(fin->fin_group, fr->fr_group, FR_GROUPLEN); fin->fin_icode = fr->fr_icode; } fin->fin_rule = is->is_rulen; pass = is->is_pass; fr_updatestate(fin, is, ifq); if (fin->fin_out == 1) fin->fin_nat = is->is_nat[fin->fin_rev]; fin->fin_state = is; is->is_touched = fr_ticks; MUTEX_ENTER(&is->is_lock); is->is_ref++; MUTEX_EXIT(&is->is_lock); RWLOCK_EXIT(&ipf_state); fin->fin_flx |= FI_STATE; if ((pass & FR_LOGFIRST) != 0) pass &= ~(FR_LOGFIRST|FR_LOG); *passp = pass; return fr; } /* ------------------------------------------------------------------------ */ /* Function: fr_fixoutisn */ /* Returns: Nil */ /* Parameters: fin(I) - pointer to packet information */ /* is(I) - pointer to master state structure */ /* */ /* Called only for outbound packets, adjusts the sequence number and the */ /* TCP checksum to match that change. */ /* ------------------------------------------------------------------------ */ static void fr_fixoutisn(fin, is) fr_info_t *fin; ipstate_t *is; { tcphdr_t *tcp; int rev; u_32_t seq; tcp = fin->fin_dp; rev = fin->fin_rev; if ((is->is_flags & IS_ISNSYN) != 0) { if (rev == 0) { seq = ntohl(tcp->th_seq); seq += is->is_isninc[0]; tcp->th_seq = htonl(seq); fix_outcksum(fin, &tcp->th_sum, is->is_sumd[0]); } } if ((is->is_flags & IS_ISNACK) != 0) { if (rev == 1) { seq = ntohl(tcp->th_seq); seq += is->is_isninc[1]; tcp->th_seq = htonl(seq); fix_outcksum(fin, &tcp->th_sum, is->is_sumd[1]); } } } /* ------------------------------------------------------------------------ */ /* Function: fr_fixinisn */ /* Returns: Nil */ /* Parameters: fin(I) - pointer to packet information */ /* is(I) - pointer to master state structure */ /* */ /* Called only for inbound packets, adjusts the acknowledge number and the */ /* TCP checksum to match that change. */ /* ------------------------------------------------------------------------ */ static void fr_fixinisn(fin, is) fr_info_t *fin; ipstate_t *is; { tcphdr_t *tcp; int rev; u_32_t ack; tcp = fin->fin_dp; rev = fin->fin_rev; if ((is->is_flags & IS_ISNSYN) != 0) { if (rev == 1) { ack = ntohl(tcp->th_ack); ack -= is->is_isninc[0]; tcp->th_ack = htonl(ack); fix_incksum(fin, &tcp->th_sum, is->is_sumd[0]); } } if ((is->is_flags & IS_ISNACK) != 0) { if (rev == 0) { ack = ntohl(tcp->th_ack); ack -= is->is_isninc[1]; tcp->th_ack = htonl(ack); fix_incksum(fin, &tcp->th_sum, is->is_sumd[1]); } } } /* ------------------------------------------------------------------------ */ /* Function: fr_statesync */ /* Returns: Nil */ /* Parameters: ifp(I) - pointer to interface */ /* */ /* Walk through all state entries and if an interface pointer match is */ /* found then look it up again, based on its name in case the pointer has */ /* changed since last time. */ /* */ /* If ifp is passed in as being non-null then we are only doing updates for */ /* existing, matching, uses of it. */ /* ------------------------------------------------------------------------ */ void fr_statesync(ifp) void *ifp; { ipstate_t *is; int i; if (fr_running <= 0) return; WRITE_ENTER(&ipf_state); if (fr_running <= 0) { RWLOCK_EXIT(&ipf_state); return; } for (is = ips_list; is; is = is->is_next) { /* * Look up all the interface names in the state entry. */ for (i = 0; i < 4; i++) { if (ifp == NULL || ifp == is->is_ifp[i]) is->is_ifp[i] = fr_resolvenic(is->is_ifname[i], is->is_v); } } RWLOCK_EXIT(&ipf_state); } /* ------------------------------------------------------------------------ */ /* Function: fr_delstate */ /* Returns: Nil */ /* Parameters: is(I) - pointer to state structure to delete */ /* why(I) - if not 0, log reason why it was deleted */ /* Write Locks: ipf_state */ /* */ /* Deletes a state entry from the enumerated list as well as the hash table */ /* and timeout queue lists. Make adjustments to hash table statistics and */ /* global counters as required. */ /* ------------------------------------------------------------------------ */ static void fr_delstate(is, why) ipstate_t *is; int why; { ASSERT(rw_read_locked(&ipf_state.ipf_lk) == 0); /* * Since we want to delete this, remove it from the state table, * where it can be found & used, first. */ if (is->is_pnext != NULL) { *is->is_pnext = is->is_next; if (is->is_next != NULL) is->is_next->is_pnext = is->is_pnext; is->is_pnext = NULL; is->is_next = NULL; } if (is->is_phnext != NULL) { *is->is_phnext = is->is_hnext; if (is->is_hnext != NULL) is->is_hnext->is_phnext = is->is_phnext; if (ips_table[is->is_hv] == NULL) ips_stats.iss_inuse--; ips_stats.iss_bucketlen[is->is_hv]--; is->is_phnext = NULL; is->is_hnext = NULL; } /* * Because ips_stats.iss_wild is a count of entries in the state * table that have wildcard flags set, only decerement it once * and do it here. */ if (is->is_flags & (SI_WILDP|SI_WILDA)) { if (!(is->is_flags & SI_CLONED)) { ATOMIC_DECL(ips_stats.iss_wild); } is->is_flags &= ~(SI_WILDP|SI_WILDA); } /* * Next, remove it from the timeout queue it is in. */ fr_deletequeueentry(&is->is_sti); if (is->is_me != NULL) { *is->is_me = NULL; is->is_me = NULL; } /* * If it is still in use by something else, do not go any further, * but note that at this point it is now an orphan. */ is->is_ref--; if (is->is_ref > 0) return; if (is->is_tqehead[0] != NULL) { if (fr_deletetimeoutqueue(is->is_tqehead[0]) == 0) fr_freetimeoutqueue(is->is_tqehead[0]); } if (is->is_tqehead[1] != NULL) { if (fr_deletetimeoutqueue(is->is_tqehead[1]) == 0) fr_freetimeoutqueue(is->is_tqehead[1]); } #ifdef IPFILTER_SYNC if (is->is_sync) ipfsync_del(is->is_sync); #endif #ifdef IPFILTER_SCAN (void) ipsc_detachis(is); #endif if (ipstate_logging != 0 && why != 0) ipstate_log(is, why); if (is->is_rule != NULL) { is->is_rule->fr_statecnt--; (void)fr_derefrule(&is->is_rule); } MUTEX_DESTROY(&is->is_lock); KFREE(is); ips_num--; } /* ------------------------------------------------------------------------ */ /* Function: fr_timeoutstate */ /* Returns: Nil */ /* Parameters: Nil */ /* */ /* Slowly expire held state for thingslike UDP and ICMP. The algorithm */ /* used here is to keep the queue sorted with the oldest things at the top */ /* and the youngest at the bottom. So if the top one doesn't need to be */ /* expired then neither will any under it. */ /* ------------------------------------------------------------------------ */ void fr_timeoutstate() { ipftq_t *ifq, *ifqnext; ipftqent_t *tqe, *tqn; ipstate_t *is; #if defined(USE_SPL) && defined(_KERNEL) int s; #endif SPL_NET(s); WRITE_ENTER(&ipf_state); for (ifq = ips_tqtqb; ifq != NULL; ifq = ifq->ifq_next) for (tqn = ifq->ifq_head; ((tqe = tqn) != NULL); ) { if (tqe->tqe_die > fr_ticks) break; tqn = tqe->tqe_next; is = tqe->tqe_parent; fr_delstate(is, ISL_EXPIRE); } for (ifq = ips_utqe; ifq != NULL; ifq = ifqnext) { ifqnext = ifq->ifq_next; for (tqn = ifq->ifq_head; ((tqe = tqn) != NULL); ) { if (tqe->tqe_die > fr_ticks) break; tqn = tqe->tqe_next; is = tqe->tqe_parent; fr_delstate(is, ISL_EXPIRE); } } for (ifq = ips_utqe; ifq != NULL; ifq = ifqnext) { ifqnext = ifq->ifq_next; if (((ifq->ifq_flags & IFQF_DELETE) != 0) && (ifq->ifq_ref == 0)) { fr_freetimeoutqueue(ifq); } } if (fr_state_doflush) { (void) fr_state_flush(2, 0); fr_state_doflush = 0; } RWLOCK_EXIT(&ipf_state); SPL_X(s); } /* ------------------------------------------------------------------------ */ /* Function: fr_state_flush */ /* Returns: int - 0 == success, -1 == failure */ /* Parameters: Nil */ /* Write Locks: ipf_state */ /* */ /* Flush state tables. Three 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. */ /* which == 2 : flush TCP connections which have been idle for a long time, */ /* starting at > 4 days idle and working back in successive half-*/ /* days to at most 12 hours old. If this fails to free enough */ /* slots then work backwards in half hour slots to 30 minutes. */ /* If that too fails, then work backwards in 30 second intervals */ /* for the last 30 minutes to at worst 30 seconds idle. */ /* ------------------------------------------------------------------------ */ static int fr_state_flush(which, proto) int which, proto; { ipftq_t *ifq, *ifqnext; ipftqent_t *tqe, *tqn; ipstate_t *is, **isp; int delete, removed; long try, maxtick; u_long interval; #if defined(_KERNEL) && !defined(MENTAT) && defined(USE_SPL) int s; #endif removed = 0; SPL_NET(s); for (isp = &ips_list; ((is = *isp) != NULL); ) { delete = 0; if ((proto != 0) && (is->is_v != proto)) { isp = &is->is_next; continue; } switch (which) { case 0 : delete = 1; break; case 1 : case 2 : if (is->is_p != IPPROTO_TCP) break; if ((is->is_state[0] != IPF_TCPS_ESTABLISHED) || (is->is_state[1] != IPF_TCPS_ESTABLISHED)) delete = 1; break; } if (delete) { if (is->is_p == IPPROTO_TCP) ips_stats.iss_fin++; else ips_stats.iss_expire++; fr_delstate(is, ISL_FLUSH); removed++; } else isp = &is->is_next; } if (which != 2) { SPL_X(s); return removed; } /* * Asked to remove inactive entries because the table is full, try * again, 3 times, if first attempt failed with a different criteria * each time. The order tried in must be in decreasing age. * Another alternative is to implement random drop and drop N entries * at random until N have been freed up. */ if (fr_ticks - ips_last_force_flush < IPF_TTLVAL(5)) goto force_flush_skipped; ips_last_force_flush = fr_ticks; if (fr_ticks > IPF_TTLVAL(43200)) interval = IPF_TTLVAL(43200); else if (fr_ticks > IPF_TTLVAL(1800)) interval = IPF_TTLVAL(1800); else if (fr_ticks > IPF_TTLVAL(30)) interval = IPF_TTLVAL(30); else interval = IPF_TTLVAL(10); try = fr_ticks - (fr_ticks - interval); if (try < 0) goto force_flush_skipped; while (removed == 0) { maxtick = fr_ticks - interval; if (maxtick < 0) break; while (try < maxtick) { for (ifq = ips_tqtqb; ifq != NULL; ifq = ifq->ifq_next) { for (tqn = ifq->ifq_head; ((tqe = tqn) != NULL); ) { if (tqe->tqe_die > try) break; tqn = tqe->tqe_next; is = tqe->tqe_parent; fr_delstate(is, ISL_EXPIRE); removed++; } } for (ifq = ips_utqe; ifq != NULL; ifq = ifqnext) { ifqnext = ifq->ifq_next; for (tqn = ifq->ifq_head; ((tqe = tqn) != NULL); ) { if (tqe->tqe_die > try) break; tqn = tqe->tqe_next; is = tqe->tqe_parent; fr_delstate(is, ISL_EXPIRE); removed++; } } if (try + interval > maxtick) break; try += interval; } if (removed == 0) { if (interval == IPF_TTLVAL(43200)) { interval = IPF_TTLVAL(1800); } else if (interval == IPF_TTLVAL(1800)) { interval = IPF_TTLVAL(30); } else if (interval == IPF_TTLVAL(30)) { interval = IPF_TTLVAL(10); } else { break; } } } force_flush_skipped: SPL_X(s); return removed; } /* ------------------------------------------------------------------------ */ /* Function: fr_tcp_age */ /* Returns: int - 1 == state transition made, 0 == no change (rejected) */ /* Parameters: tq(I) - pointer to timeout queue information */ /* fin(I) - pointer to packet information */ /* tqtab(I) - TCP timeout queue table this is in */ /* flags(I) - flags from state/NAT entry */ /* */ /* Rewritten by Arjan de Vet , 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. */ /* */ /* Internal 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 */ /* */ /* Locking: it is assumed that the parent of the tqe structure is locked. */ /* ------------------------------------------------------------------------ */ int fr_tcp_age(tqe, fin, tqtab, flags) ipftqent_t *tqe; fr_info_t *fin; ipftq_t *tqtab; int flags; { int dlen, ostate, nstate, rval, dir; u_char tcpflags; tcphdr_t *tcp; tcp = fin->fin_dp; rval = 0; dir = fin->fin_rev; tcpflags = tcp->th_flags; dlen = fin->fin_plen - fin->fin_hlen - (TCP_OFF(tcp) << 2); if (tcpflags & TH_RST) { if (!(tcpflags & TH_PUSH) && !dlen) nstate = IPF_TCPS_CLOSED; else nstate = IPF_TCPS_CLOSE_WAIT; rval = 1; } else { ostate = tqe->tqe_state[1 - dir]; nstate = tqe->tqe_state[dir]; switch (nstate) { case IPF_TCPS_CLOSED: /* 0 */ if ((tcpflags & TH_OPENING) == TH_OPENING) { /* * 'dir' received an S and sends SA in * response, CLOSED -> SYN_RECEIVED */ nstate = IPF_TCPS_SYN_RECEIVED; rval = 1; } else if ((tcpflags & TH_OPENING) == TH_SYN) { /* 'dir' sent S, CLOSED -> SYN_SENT */ nstate = IPF_TCPS_SYN_SENT; rval = 1; } /* * 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 & IS_TCPFSM) == 0) && ((tcpflags & TH_ACKMASK) == TH_ACK)) { /* * we saw an A, guess 'dir' is in ESTABLISHED * mode */ switch (ostate) { case IPF_TCPS_CLOSED : case IPF_TCPS_SYN_RECEIVED : nstate = IPF_TCPS_HALF_ESTAB; rval = 1; break; case IPF_TCPS_HALF_ESTAB : case IPF_TCPS_ESTABLISHED : nstate = IPF_TCPS_ESTABLISHED; rval = 1; break; default : break; } } /* * 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 IPF_TCPS_LISTEN: /* 1 */ /* NOT USED */ break; case IPF_TCPS_SYN_SENT: /* 2 */ if ((tcpflags & ~(TH_ECN|TH_CWR)) == TH_SYN) { /* * A retransmitted SYN packet. We do not reset * the timeout here to fr_tcptimeout because a * connection connect timeout does not renew * after every packet that is sent. We need to * set rval so as to indicate the packet has * passed the check for its flags being valid * in the TCP FSM. Setting rval to 2 has the * result of not resetting the timeout. */ rval = 2; } else if ((tcpflags & (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 */ nstate = IPF_TCPS_ESTABLISHED; rval = 1; } else if (tcpflags & 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 */ nstate = IPF_TCPS_FIN_WAIT_1; rval = 1; } else if ((tcpflags & 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 */ nstate = IPF_TCPS_SYN_RECEIVED; rval = 1; } break; case IPF_TCPS_SYN_RECEIVED: /* 3 */ if ((tcpflags & (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 */ nstate = IPF_TCPS_ESTABLISHED; rval = 1; } else if ((tcpflags & ~(TH_ECN|TH_CWR)) == TH_OPENING) { /* * We see an SA from 'dir' which is already in * SYN_RECEIVED state. */ rval = 2; } else if (tcpflags & 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 */ nstate = IPF_TCPS_FIN_WAIT_1; rval = 1; } break; case IPF_TCPS_HALF_ESTAB: /* 4 */ if (ostate >= IPF_TCPS_HALF_ESTAB) { if ((tcpflags & TH_ACKMASK) == TH_ACK) { nstate = IPF_TCPS_ESTABLISHED; rval = 1; } } break; case IPF_TCPS_ESTABLISHED: /* 5 */ rval = 1; if (tcpflags & TH_FIN) { /* * 'dir' closed its side of the connection; * this gives us a half-closed connection; * ESTABLISHED -> FIN_WAIT_1 */ nstate = IPF_TCPS_FIN_WAIT_1; } else if (tcpflags & TH_ACK) { /* * an ACK, should we exclude other flags here? */ if (ostate == IPF_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 */ nstate = IPF_TCPS_CLOSE_WAIT; } else if (ostate < IPF_TCPS_CLOSE_WAIT) { /* * still a fully established * connection reset timeout */ nstate = IPF_TCPS_ESTABLISHED; } } break; case IPF_TCPS_CLOSE_WAIT: /* 6 */ rval = 1; if (tcpflags & TH_FIN) { /* * application closed and 'dir' sent a FIN, * we're now going into LAST_ACK state */ nstate = IPF_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 */ nstate = IPF_TCPS_CLOSE_WAIT; } break; case IPF_TCPS_FIN_WAIT_1: /* 7 */ rval = 1; if ((tcpflags & TH_ACK) && ostate > IPF_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? */ nstate = IPF_TCPS_TIME_WAIT; } 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 */ nstate = IPF_TCPS_FIN_WAIT_1; } break; case IPF_TCPS_CLOSING: /* 8 */ /* NOT USED */ break; case IPF_TCPS_LAST_ACK: /* 9 */ if (tcpflags & TH_ACK) { if ((tcpflags & TH_PUSH) || dlen) /* * there is still data to be delivered, * reset timeout */ rval = 1; else rval = 2; } /* * 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 IPF_TCPS_FIN_WAIT_2: /* 10 */ rval = 1; if ((tcpflags & TH_OPENING) == TH_OPENING) nstate = IPF_TCPS_SYN_RECEIVED; else if (tcpflags & TH_SYN) nstate = IPF_TCPS_SYN_SENT; break; case IPF_TCPS_TIME_WAIT: /* 11 */ /* we're in 2MSL timeout now */ rval = 1; break; default : #if defined(_KERNEL) # if SOLARIS cmn_err(CE_NOTE, "tcp %lx flags %x si %lx nstate %d ostate %d\n", (u_long)tcp, tcpflags, (u_long)tqe, nstate, ostate); # else printf("tcp %lx flags %x si %lx nstate %d ostate %d\n", (u_long)tcp, tcpflags, (u_long)tqe, nstate, ostate); # endif # ifdef DIAGNOSTIC panic("invalid TCP state"); # endif #else abort(); #endif break; } } /* * If rval == 2 then do not update the queue position, but treat the * packet as being ok. */ if (rval == 2) rval = 1; else if (rval == 1) { tqe->tqe_state[dir] = nstate; if ((tqe->tqe_flags & TQE_RULEBASED) == 0) fr_movequeue(tqe, tqe->tqe_ifq, tqtab + nstate); } return rval; } /* ------------------------------------------------------------------------ */ /* Function: ipstate_log */ /* Returns: Nil */ /* Parameters: is(I) - pointer to state structure */ /* type(I) - type of log entry to create */ /* */ /* Creates a state table log entry using the state structure and type info. */ /* passed in. Log packet/byte counts, source/destination address and other */ /* protocol specific information. */ /* ------------------------------------------------------------------------ */ void ipstate_log(is, type) struct ipstate *is; u_int type; { #ifdef IPFILTER_LOG struct ipslog ipsl; size_t sizes[1]; void *items[1]; int types[1]; /* * Copy information out of the ipstate_t structure and into the * structure used for logging. */ ipsl.isl_type = type; ipsl.isl_pkts[0] = is->is_pkts[0] + is->is_icmppkts[0]; ipsl.isl_bytes[0] = is->is_bytes[0]; ipsl.isl_pkts[1] = is->is_pkts[1] + is->is_icmppkts[1]; ipsl.isl_bytes[1] = is->is_bytes[1]; ipsl.isl_pkts[2] = is->is_pkts[2] + is->is_icmppkts[2]; ipsl.isl_bytes[2] = is->is_bytes[2]; ipsl.isl_pkts[3] = is->is_pkts[3] + is->is_icmppkts[3]; ipsl.isl_bytes[3] = is->is_bytes[3]; 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; ipsl.isl_tag = is->is_tag; ipsl.isl_rulen = is->is_rulen; (void) strncpy(ipsl.isl_group, is->is_group, FR_GROUPLEN); 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.ici_type; } else if (ipsl.isl_p == IPPROTO_ICMPV6) { ipsl.isl_itype = is->is_icmp.ici_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; if (ipllog(IPL_LOGSTATE, NULL, items, sizes, types, 1)) { ATOMIC_INCL(ips_stats.iss_logged); } else { ATOMIC_INCL(ips_stats.iss_logfail); } #endif } #ifdef USE_INET6 /* ------------------------------------------------------------------------ */ /* Function: fr_checkicmp6matchingstate */ /* Returns: ipstate_t* - NULL == no match found, */ /* else pointer to matching state entry */ /* Parameters: fin(I) - pointer to packet information */ /* Locks: NULL == no locks, else Read Lock on ipf_state */ /* */ /* If we've got an ICMPv6 error message, using the information stored in */ /* the ICMPv6 packet, look for a matching state table entry. */ /* ------------------------------------------------------------------------ */ static ipstate_t *fr_checkicmp6matchingstate(fin) fr_info_t *fin; { struct icmp6_hdr *ic6, *oic; int type, backward, i; ipstate_t *is, **isp; u_short sport, dport; i6addr_t dst, src; u_short savelen; icmpinfo_t *ic; fr_info_t ofin; tcphdr_t *tcp; ip6_t *oip6; u_char pr; 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; ic6 = fin->fin_dp; type = ic6->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; oip6 = (ip6_t *)((char *)ic6 + ICMPERR_ICMPHLEN); if (fin->fin_plen < sizeof(*oip6)) return NULL; bcopy((char *)fin, (char *)&ofin, sizeof(fin)); ofin.fin_v = 6; ofin.fin_ifp = fin->fin_ifp; ofin.fin_out = !fin->fin_out; ofin.fin_m = NULL; /* if dereferenced, panic XXX */ ofin.fin_mp = NULL; /* if dereferenced, panic XXX */ /* * We make a fin entry to be able to feed it to * matchsrcdst. Note that not all fields are necessary * 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 oip6 in network * order. Any change we make must be undone afterwards. */ savelen = oip6->ip6_plen; oip6->ip6_plen = fin->fin_dlen - ICMPERR_ICMPHLEN; ofin.fin_flx = FI_NOCKSUM; ofin.fin_ip = (ip_t *)oip6; ofin.fin_plen = oip6->ip6_plen; (void) fr_makefrip(sizeof(*oip6), (ip_t *)oip6, &ofin); ofin.fin_flx &= ~(FI_BAD|FI_SHORT); oip6->ip6_plen = savelen; if (oip6->ip6_nxt == IPPROTO_ICMPV6) { oic = (struct icmp6_hdr *)(oip6 + 1); /* * an 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 = oip6->ip6_nxt); src.in6 = oip6->ip6_src; hv += src.in4.s_addr; dst.in6 = oip6->ip6_dst; hv += dst.in4.s_addr; hv += oic->icmp6_id; hv += oic->icmp6_seq; hv = DOUBLE_HASH(hv); READ_ENTER(&ipf_state); for (isp = &ips_table[hv]; ((is = *isp) != NULL); ) { ic = &is->is_icmp; isp = &is->is_hnext; if ((is->is_p == pr) && !(is->is_pass & FR_NOICMPERR) && (oic->icmp6_id == ic->ici_id) && (oic->icmp6_seq == ic->ici_seq) && (is = fr_matchsrcdst(&ofin, is, &src, &dst, NULL, FI_ICMPCMP))) { /* * in the state table ICMP query's are stored * with the type of the corresponding ICMP * response. Correct here */ if (((ic->ici_type == ICMP6_ECHO_REPLY) && (oic->icmp6_type == ICMP6_ECHO_REQUEST)) || (ic->ici_type - 1 == oic->icmp6_type )) { ips_stats.iss_hits++; backward = IP6_NEQ(&is->is_dst, &src); fin->fin_rev = !backward; i = (backward << 1) + fin->fin_out; is->is_icmppkts[i]++; return is; } } } RWLOCK_EXIT(&ipf_state); return NULL; } hv = (pr = oip6->ip6_nxt); src.in6 = oip6->ip6_src; hv += src.i6[0]; hv += src.i6[1]; hv += src.i6[2]; hv += src.i6[3]; dst.in6 = oip6->ip6_dst; hv += dst.i6[0]; hv += dst.i6[1]; hv += dst.i6[2]; hv += dst.i6[3]; if ((oip6->ip6_nxt == IPPROTO_TCP) || (oip6->ip6_nxt == IPPROTO_UDP)) { tcp = (tcphdr_t *)(oip6 + 1); dport = tcp->th_dport; sport = tcp->th_sport; hv += dport; hv += sport; } else tcp = NULL; hv = DOUBLE_HASH(hv); READ_ENTER(&ipf_state); for (isp = &ips_table[hv]; ((is = *isp) != NULL); ) { 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) || (is->is_pass & FR_NOICMPERR)) continue; is = fr_matchsrcdst(&ofin, is, &src, &dst, tcp, FI_ICMPCMP); if (is != NULL) { ips_stats.iss_hits++; backward = IP6_NEQ(&is->is_dst, &src); fin->fin_rev = !backward; i = (backward << 1) + fin->fin_out; is->is_icmppkts[i]++; /* * we deliberately do not touch the timeouts * for the accompanying state table entry. * It remains to be seen if that is correct. XXX */ return is; } } RWLOCK_EXIT(&ipf_state); return NULL; } #endif /* ------------------------------------------------------------------------ */ /* Function: fr_sttab_init */ /* Returns: Nil */ /* Parameters: tqp(I) - pointer to an array of timeout queues for TCP */ /* */ /* Initialise the array of timeout queues for TCP. */ /* ------------------------------------------------------------------------ */ void fr_sttab_init(tqp) ipftq_t *tqp; { int i; for (i = IPF_TCP_NSTATES - 1; i >= 0; i--) { tqp[i].ifq_ttl = 0; tqp[i].ifq_ref = 1; tqp[i].ifq_head = NULL; tqp[i].ifq_tail = &tqp[i].ifq_head; tqp[i].ifq_next = tqp + i + 1; MUTEX_INIT(&tqp[i].ifq_lock, "ipftq tcp tab"); } tqp[IPF_TCP_NSTATES - 1].ifq_next = NULL; tqp[IPF_TCPS_CLOSED].ifq_ttl = fr_tcpclosed; tqp[IPF_TCPS_LISTEN].ifq_ttl = fr_tcptimeout; tqp[IPF_TCPS_SYN_SENT].ifq_ttl = fr_tcptimeout; tqp[IPF_TCPS_SYN_RECEIVED].ifq_ttl = fr_tcptimeout; tqp[IPF_TCPS_ESTABLISHED].ifq_ttl = fr_tcpidletimeout; tqp[IPF_TCPS_CLOSE_WAIT].ifq_ttl = fr_tcphalfclosed; tqp[IPF_TCPS_FIN_WAIT_1].ifq_ttl = fr_tcphalfclosed; tqp[IPF_TCPS_CLOSING].ifq_ttl = fr_tcptimeout; tqp[IPF_TCPS_LAST_ACK].ifq_ttl = fr_tcplastack; tqp[IPF_TCPS_FIN_WAIT_2].ifq_ttl = fr_tcpclosewait; tqp[IPF_TCPS_TIME_WAIT].ifq_ttl = fr_tcptimeout; tqp[IPF_TCPS_HALF_ESTAB].ifq_ttl = fr_tcptimeout; } /* ------------------------------------------------------------------------ */ /* Function: fr_sttab_destroy */ /* Returns: Nil */ /* Parameters: tqp(I) - pointer to an array of timeout queues for TCP */ /* */ /* Do whatever is necessary to "destroy" each of the entries in the array */ /* of timeout queues for TCP. */ /* ------------------------------------------------------------------------ */ void fr_sttab_destroy(tqp) ipftq_t *tqp; { int i; for (i = IPF_TCP_NSTATES - 1; i >= 0; i--) MUTEX_DESTROY(&tqp[i].ifq_lock); } /* ------------------------------------------------------------------------ */ /* Function: fr_statederef */ /* Returns: Nil */ /* Parameters: isp(I) - pointer to pointer to state table entry */ /* */ /* Decrement the reference counter for this state table entry and free it */ /* if there are no more things using it. */ /* */ /* When operating in userland (ipftest), we have no timers to clear a state */ /* entry. Therefore, we make a few simple tests before deleting an entry */ /* outright. We compare states on each side looking for a combination of */ /* TIME_WAIT (should really be FIN_WAIT_2?) and LAST_ACK. Then we factor */ /* in packet direction with the interface list to make sure we don't */ /* prematurely delete an entry on a final inbound packet that's we're also */ /* supposed to route elsewhere. */ /* */ /* Internal 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_statederef(fin, isp) fr_info_t *fin; ipstate_t **isp; { ipstate_t *is = *isp; #if 0 int nstate, ostate, dir, eol; eol = 0; /* End-of-the-line flag. */ dir = fin->fin_rev; ostate = is->is_state[1 - dir]; nstate = is->is_state[dir]; /* * Determine whether this packet is local or routed. State entries * with us as the destination will have an interface list of * int1,-,-,int1. Entries with us as the origin run as -,int1,int1,-. */ if ((fin->fin_p == IPPROTO_TCP) && (fin->fin_out == 0)) { if ((strcmp(is->is_ifname[0], is->is_ifname[3]) == 0) && (strcmp(is->is_ifname[1], is->is_ifname[2]) == 0)) { if ((dir == 0) && (strcmp(is->is_ifname[1], "-") == 0) && (strcmp(is->is_ifname[0], "-") != 0)) { eol = 1; } else if ((dir == 1) && (strcmp(is->is_ifname[0], "-") == 0) && (strcmp(is->is_ifname[1], "-") != 0)) { eol = 1; } } } #endif fin = fin; /* LINT */ is = *isp; *isp = NULL; WRITE_ENTER(&ipf_state); is->is_ref--; if (is->is_ref == 0) { is->is_ref++; /* To counter ref-- in fr_delstate() */ fr_delstate(is, ISL_EXPIRE); #ifndef _KERNEL #if 0 } else if (((fin->fin_out == 1) || (eol == 1)) && ((ostate == IPF_TCPS_LAST_ACK) && (nstate == IPF_TCPS_TIME_WAIT))) { ; #else } else if ((is->is_sti.tqe_state[0] > IPF_TCPS_ESTABLISHED) || (is->is_sti.tqe_state[1] > IPF_TCPS_ESTABLISHED)) { #endif fr_delstate(is, ISL_ORPHAN); #endif } RWLOCK_EXIT(&ipf_state); } /* ------------------------------------------------------------------------ */ /* Function: fr_setstatequeue */ /* Returns: Nil */ /* Parameters: is(I) - pointer to state structure */ /* rev(I) - forward(0) or reverse(1) direction */ /* Locks: ipf_state (read or write) */ /* */ /* Put the state entry on its default queue entry, using rev as a helped in */ /* determining which queue it should be placed on. */ /* ------------------------------------------------------------------------ */ void fr_setstatequeue(is, rev) ipstate_t *is; int rev; { ipftq_t *oifq, *nifq; if ((is->is_sti.tqe_flags & TQE_RULEBASED) != 0) nifq = is->is_tqehead[rev]; else nifq = NULL; if (nifq == NULL) { switch (is->is_p) { #ifdef USE_INET6 case IPPROTO_ICMPV6 : if (rev == 1) nifq = &ips_icmpacktq; else nifq = &ips_icmptq; break; #endif case IPPROTO_ICMP : if (rev == 1) nifq = &ips_icmpacktq; else nifq = &ips_icmptq; break; case IPPROTO_TCP : nifq = ips_tqtqb + is->is_state[rev]; break; case IPPROTO_UDP : if (rev == 1) nifq = &ips_udpacktq; else nifq = &ips_udptq; break; default : nifq = &ips_iptq; break; } } oifq = is->is_sti.tqe_ifq; /* * If it's currently on a timeout queue, move it from one queue to * another, else put it on the end of the newly determined queue. */ if (oifq != NULL) fr_movequeue(&is->is_sti, oifq, nifq); else fr_queueappend(&is->is_sti, nifq, is); return; }