/* * (C)opyright 1993,1994,1995 by Darren Reed. * * Redistribution and use in source and binary forms are permitted * provided that this notice is preserved and due credit is given * to the original author and the contributors. */ #if !defined(lint) && defined(LIBC_SCCS) static char sccsid[] = "@(#)ip_fil.c 2.41 6/5/96 (C) 1993-1995 Darren Reed"; static char rcsid[] = "$Id: ip_fil.c,v 2.0.1.7 1997/02/19 12:45:02 darrenr Exp $"; #endif #include #include #include #include #include #include #include #include #include #include #include #ifdef sun #include #endif #include #include #include #include #include #include #include #include #include #include #include #include "ip_fil.h" #include "ip_compat.h" #include "ip_frag.h" #include "ip_nat.h" #include "ip_state.h" #ifndef MIN #define MIN(a,b) (((a)<(b))?(a):(b)) #endif extern fr_flags, fr_active; extern struct protosw inetsw[]; extern int (*fr_checkp)(); #if BSD < 199306 extern int ipfr_slowtimer(); static int (*fr_saveslowtimo)(); extern int tcp_ttl; #else extern void ipfr_slowtimer(); static void (*fr_saveslowtimo)(); #endif int ipl_inited = 0; int ipl_unreach = ICMP_UNREACH_FILTER; int send_reset(); #ifdef IPFILTER_LOG # define LOGSIZE 8192 int ipllog(); char iplbuf[LOGSIZE]; caddr_t iplh = iplbuf, iplt = iplbuf; static int iplused = 0; #endif /* IPFILTER_LOG */ static void frflush(); static int frrequest(); static int (*fr_savep)() = NULL; #if _BSDI_VERSION >= 199501 # include # include int iplioctl __P((dev_t, int, caddr_t, int, struct proc *)); int iplopen __P((dev_t, int, int, struct proc *)); int iplclose __P((dev_t, int, int, struct proc *)); # ifdef IPFILTER_LOG int iplread __P((dev_t, struct uio *, int)); # else # define iplread noread # endif int iplioctl __P((dev_t, int, caddr_t, int, struct proc *)); struct cfdriver iplcd = { NULL, "ipl", NULL, NULL, DV_DULL, 0 }; struct devsw iplsw = { &iplcd, iplopen, iplclose, iplread, nowrite, iplioctl, noselect, nommap, nostrat, nodump, nopsize, 0, nostop }; #endif /* _BSDI_VERSION >= 199501 */ #ifdef IPFILTER_LKM int iplidentify(s) char *s; { if (strcmp(s, "ipl") == 0) return 1; return 0; } #endif /* IPFILTER_LKM */ int iplattach() { int s; SPLNET(s); if (ipl_inited || (fr_checkp == fr_check)) { printf("IP Filter: already initialized\n"); SPLX(s); return EBUSY; } ipl_inited = 1; bzero((char *)nat_table, sizeof(nat_t *) * NAT_SIZE * 2); fr_savep = fr_checkp; fr_checkp = fr_check; fr_saveslowtimo = inetsw[0].pr_slowtimo; inetsw[0].pr_slowtimo = ipfr_slowtimer; SPLX(s); return 0; } int ipldetach() { int s, i = FR_INQUE|FR_OUTQUE; SPLNET(s); if (!ipl_inited) { printf("IP Filter: not initialized\n"); SPLX(s); return EBUSY; } fr_checkp = fr_savep; inetsw[0].pr_slowtimo = fr_saveslowtimo; frflush((caddr_t)&i); ipl_inited = 0; ipfr_unload(); ip_natunload(); fr_stateunload(); SPLX(s); return 0; } static void frzerostats(data) caddr_t data; { struct friostat fio; bcopy((char *)frstats, (char *)fio.f_st, sizeof(struct filterstats) * 2); fio.f_fin[0] = ipfilter[0][0]; fio.f_fin[1] = ipfilter[0][1]; fio.f_fout[0] = ipfilter[1][0]; fio.f_fout[1] = ipfilter[1][1]; fio.f_acctin[0] = ipacct[0][0]; fio.f_acctin[1] = ipacct[0][1]; fio.f_acctout[0] = ipacct[1][0]; fio.f_acctout[1] = ipacct[1][1]; fio.f_active = fr_active; IWCOPY((caddr_t)&fio, data, sizeof(fio)); bzero((char *)frstats, sizeof(*frstats) * 2); } static void frflush(data) caddr_t data; { struct frentry *f, **fp; int flags = *(int *)data, flushed = 0, set = fr_active; bzero((char *)frcache, sizeof(frcache[0]) * 2); if (flags & FR_INACTIVE) set = 1 - set; if (flags & FR_OUTQUE) { for (fp = &ipfilter[1][set]; (f = *fp); ) { *fp = f->fr_next; KFREE(f); flushed++; } for (fp = &ipacct[1][set]; (f = *fp); ) { *fp = f->fr_next; KFREE(f); flushed++; } } if (flags & FR_INQUE) { for (fp = &ipfilter[0][set]; (f = *fp); ) { *fp = f->fr_next; KFREE(f); flushed++; } for (fp = &ipacct[0][set]; (f = *fp); ) { *fp = f->fr_next; KFREE(f); flushed++; } } *(int *)data = flushed; } /* * Filter ioctl interface. */ int iplioctl(dev, cmd, data, mode #if _BSDI_VERSION >= 199501 , p) struct proc *p; #else ) #endif dev_t dev; int cmd; caddr_t data; int mode; { int error = 0, s, unit; unit = minor(dev); if (unit != 0) return ENXIO; SPLNET(s); switch (cmd) { case FIONREAD : #ifdef IPFILTER_LOG *(int *)data = iplused; #endif break; #ifndef IPFILTER_LKM case SIOCFRENB : { u_int enable; if (!(mode & FWRITE)) error = EPERM; else { IRCOPY(data, (caddr_t)&enable, sizeof(enable)); if (enable) error = iplattach(); else error = ipldetach(); } break; } #endif case SIOCSETFF : if (!(mode & FWRITE)) error = EPERM; else IRCOPY(data, (caddr_t)&fr_flags, sizeof(fr_flags)); break; case SIOCGETFF : IWCOPY((caddr_t)&fr_flags, data, sizeof(fr_flags)); break; case SIOCINAFR : case SIOCRMAFR : case SIOCADAFR : case SIOCZRLST : if (!(mode & FWRITE)) error = EPERM; else error = frrequest(cmd, data, fr_active); break; case SIOCINIFR : case SIOCRMIFR : case SIOCADIFR : if (!(mode & FWRITE)) error = EPERM; else error = frrequest(cmd, data, 1 - fr_active); break; case SIOCSWAPA : if (!(mode & FWRITE)) error = EPERM; else { bzero((char *)frcache, sizeof(frcache[0]) * 2); *(u_int *)data = fr_active; fr_active = 1 - fr_active; } break; case SIOCGETFS : { struct friostat fio; bcopy((char *)frstats, (char *)fio.f_st, sizeof(struct filterstats) * 2); fio.f_fin[0] = ipfilter[0][0]; fio.f_fin[1] = ipfilter[0][1]; fio.f_fout[0] = ipfilter[1][0]; fio.f_fout[1] = ipfilter[1][1]; fio.f_acctin[0] = ipacct[0][0]; fio.f_acctin[1] = ipacct[0][1]; fio.f_acctout[0] = ipacct[1][0]; fio.f_acctout[1] = ipacct[1][1]; fio.f_active = fr_active; IWCOPY((caddr_t)&fio, data, sizeof(fio)); break; } case SIOCFRZST : if (!(mode & FWRITE)) error = EPERM; else frzerostats(data); break; case SIOCIPFFL : if (!(mode & FWRITE)) error = EPERM; else frflush(data); break; #ifdef IPFILTER_LOG case SIOCIPFFB : if (!(mode & FWRITE)) error = EPERM; else { *(int *)data = iplused; iplh = iplt = iplbuf; iplused = 0; } break; #endif /* IPFILTER_LOG */ case SIOCADNAT : case SIOCRMNAT : case SIOCGNATS : case SIOCGNATL : case SIOCFLNAT : case SIOCCNATL : error = nat_ioctl(data, cmd, mode); break; case SIOCGFRST : IWCOPY((caddr_t)ipfr_fragstats(), data, sizeof(ipfrstat_t)); break; case SIOCGIPST : IWCOPY((caddr_t)fr_statetstats(), data, sizeof(ips_stat_t)); break; default : error = EINVAL; break; } SPLX(s); return error; } static int frrequest(req, data, set) int req, set; caddr_t data; { register frentry_t *fp, *f, **fprev; register frentry_t **ftail; frentry_t fr; frdest_t *fdp; struct frentry frd; int error = 0, in; fp = &fr; IRCOPY(data, (caddr_t)fp, sizeof(*fp)); bzero((char *)frcache, sizeof(frcache[0]) * 2); in = (fp->fr_flags & FR_INQUE) ? 0 : 1; if (fp->fr_flags & FR_ACCOUNT) { ftail = fprev = &ipacct[in][set]; } else if (fp->fr_flags & (FR_OUTQUE|FR_INQUE)) ftail = fprev = &ipfilter[in][set]; else return ESRCH; IRCOPY((char *)fp, (char *)&frd, sizeof(frd)); fp = &frd; if (*fp->fr_ifname) { fp->fr_ifa = GETUNIT(fp->fr_ifname); if (!fp->fr_ifa) fp->fr_ifa = (struct ifnet *)-1; } fdp = &fp->fr_dif; fp->fr_flags &= ~FR_DUP; if (*fdp->fd_ifname) { fdp->fd_ifp = GETUNIT(fdp->fd_ifname); if (!fdp->fd_ifp) fdp->fd_ifp = (struct ifnet *)-1; else fp->fr_flags |= FR_DUP; } fdp = &fp->fr_tif; if (*fdp->fd_ifname) { fdp->fd_ifp = GETUNIT(fdp->fd_ifname); if (!fdp->fd_ifp) fdp->fd_ifp = (struct ifnet *)-1; } /* * Look for a matching filter rule, but don't include the next or * interface pointer in the comparison (fr_next, fr_ifa). */ for (; (f = *ftail); ftail = &f->fr_next) if (bcmp((char *)&f->fr_ip, (char *)&fp->fr_ip, FR_CMPSIZ) == 0) break; /* * If zero'ing statistics, copy current to caller and zero. */ if (req == SIOCZRLST) { if (!f) return ESRCH; IWCOPY((caddr_t)f, data, sizeof(*f)); f->fr_hits = 0; f->fr_bytes = 0; return 0; } if (!f) { ftail = fprev; if (req != SIOCINAFR && req != SIOCINIFR) while ((f = *ftail)) ftail = &f->fr_next; else if (fp->fr_hits) while (--fp->fr_hits && (f = *ftail)) ftail = &f->fr_next; f = NULL; } if (req == SIOCDELFR || req == SIOCRMIFR) { if (!f) error = ESRCH; else { *ftail = f->fr_next; (void) KFREE(f); } } else { if (f) error = EEXIST; else { if ((f = (struct frentry *)KMALLOC(sizeof(*f)))) { bcopy((char *)fp, (char *)f, sizeof(*f)); f->fr_hits = 0; f->fr_next = *ftail; *ftail = f; } else error = ENOMEM; } } return (error); } #if !defined(linux) /* * routines below for saving IP headers to buffer */ int iplopen(dev, flags #if _BSDI_VERSION >= 199501 , devtype, p) int devtype; struct proc *p; #else ) #endif dev_t dev; int flags; { u_int min = minor(dev); if (min) min = ENXIO; return min; } int iplclose(dev, flags #if _BSDI_VERSION >= 199501 , devtype, p) int devtype; struct proc *p; #else ) #endif dev_t dev; int flags; { u_int min = minor(dev); if (min) min = ENXIO; return min; } # ifdef IPFILTER_LOG /* * iplread/ipllog * both of these must operate with at least splnet() lest they be * called during packet processing and cause an inconsistancy to appear in * the filter lists. */ # if BSD >= 199306 int iplread(dev, uio, ioflag) int ioflag; # else int iplread(dev, uio) # endif dev_t dev; register struct uio *uio; { register int ret, s; register size_t sz, sx; int error; if (!uio->uio_resid) return 0; while (!iplused) { error = SLEEP(iplbuf, "ipl sleep"); if (error) return error; } SPLNET(s); sx = sz = MIN(uio->uio_resid, iplused); if (iplh < iplt) sz = MIN(sz, LOGSIZE - (iplt - iplbuf)); sx -= sz; # if BSD >= 199306 || defined(__FreeBSD__) uio->uio_rw = UIO_READ; # endif if (!(ret = UIOMOVE(iplt, sz, UIO_READ, uio))) { iplt += sz; iplused -= sz; if ((iplh < iplt) && (iplt == iplbuf + LOGSIZE)) iplt = iplbuf; if (sx && !(ret = UIOMOVE(iplt, sx, UIO_READ, uio))) { iplt += sx; iplused -= sx; if ((iplh < iplt) && (iplt == iplbuf + LOGSIZE)) iplt = iplbuf; } if (!iplused) /* minimise wrapping around the end */ iplh = iplt = iplbuf; } SPLX(s); return ret; } # endif /* IPFILTER_LOG */ #endif /* linux */ #ifdef IPFILTER_LOG int ipllog(flags, ip, fin, m) u_int flags; ip_t *ip; register fr_info_t *fin; struct mbuf *m; { struct ipl_ci iplci; register int len, mlen, hlen; struct ifnet *ifp = fin->fin_ifp; hlen = fin->fin_hlen; if (ip->ip_p == IPPROTO_TCP || ip->ip_p == IPPROTO_UDP) hlen += MIN(sizeof(tcphdr_t), fin->fin_dlen); else if (ip->ip_p == IPPROTO_ICMP) { struct icmp *icmp = (struct icmp *)((char *)ip + hlen); switch (icmp->icmp_type) { case ICMP_UNREACH : case ICMP_SOURCEQUENCH : case ICMP_REDIRECT : case ICMP_TIMXCEED : case ICMP_PARAMPROB : hlen += MIN(sizeof(struct icmp) + 8, fin->fin_dlen); break; default : hlen += MIN(sizeof(struct icmp), fin->fin_dlen); break; } } mlen = (flags & FR_LOGBODY) ? MIN(ip->ip_len - hlen, 128) : 0; len = hlen + sizeof(iplci) + mlen; if (iplused + len > LOGSIZE) return 0; iplused += len; # ifdef sun uniqtime(&iplci); # endif # if BSD >= 199306 || defined(__FreeBSD__) microtime((struct timeval *)&iplci); # endif iplci.flags = flags; iplci.hlen = (u_char)hlen; iplci.plen = (u_char)mlen; iplci.rule = fin->fin_rule; # if (defined(NetBSD) && (NetBSD <= 1991011) && (NetBSD >= 199603)) strncpy(iplci.ifname, ifp->if_xname, IFNAMSIZ); # else iplci.unit = (u_char)ifp->if_unit; if ((iplci.ifname[0] = ifp->if_name[0])) if ((iplci.ifname[1] = ifp->if_name[1])) if ((iplci.ifname[2] = ifp->if_name[2])) iplci.ifname[3] = ifp->if_name[3]; # endif /* * Gauranteed to succeed from above */ (void) fr_copytolog(&iplci, sizeof(iplci)); for (len -= sizeof(iplci); m && len > 0; m = m->m_next, len -= hlen) { hlen = MIN(len, m->m_len); if (fr_copytolog(mtod(m, char *), hlen)) break; } wakeup(iplbuf); return 1; } #endif /* IPFILTER_LOG */ /* * send_reset - this could conceivably be a call to tcp_respond(), but that * requires a large amount of setting up and isn't any more efficient. */ int send_reset(ti) struct tcpiphdr *ti; { struct tcpiphdr *tp; struct ip *ip; struct tcphdr *tcp; struct mbuf *m; int tlen = 0; if (ti->ti_flags & TH_RST) return -1; /* feedback loop */ #if BSD < 199306 m = m_get(M_DONTWAIT, MT_HEADER); #else m = m_gethdr(M_DONTWAIT, MT_HEADER); m->m_data += max_linkhdr; #endif if (m == NULL) return -1; if (ti->ti_flags & TH_SYN) tlen = 1; m->m_len = sizeof (struct tcpiphdr); #if BSD >= 199306 m->m_pkthdr.len = sizeof (struct tcpiphdr); m->m_pkthdr.rcvif = (struct ifnet *)0; #endif bzero(mtod(m, char *), sizeof(struct tcpiphdr)); ip = mtod(m, struct ip *); tp = mtod(m, struct tcpiphdr *); tcp = (struct tcphdr *)((char *)ip + sizeof(struct ip)); ip->ip_src.s_addr = ti->ti_dst.s_addr; ip->ip_dst.s_addr = ti->ti_src.s_addr; tcp->th_dport = ti->ti_sport; tcp->th_sport = ti->ti_dport; tcp->th_ack = htonl(ntohl(ti->ti_seq) + tlen); tcp->th_off = sizeof(struct tcphdr) >> 2; tcp->th_flags = TH_RST|TH_ACK; tp->ti_pr = ((struct ip *)ti)->ip_p; tp->ti_len = htons(sizeof(struct tcphdr)); tcp->th_sum = in_cksum(m, sizeof(struct tcpiphdr)); ip->ip_tos = ((struct ip *)ti)->ip_tos; ip->ip_p = ((struct ip *)ti)->ip_p; ip->ip_len = sizeof (struct tcpiphdr); #if BSD < 199306 ip->ip_ttl = tcp_ttl; #else ip->ip_ttl = ip_defttl; #endif /* * extra 0 in case of multicast */ (void) ip_output(m, (struct mbuf *)0, 0, 0, 0); return 0; } #ifndef IPFILTER_LKM void iplinit() { (void) iplattach(); ip_init(); } #endif void ipfr_fastroute(m0, fin, fdp) struct mbuf *m0; fr_info_t *fin; frdest_t *fdp; { register struct ip *ip, *mhip; register struct mbuf *m = m0; register struct route *ro; struct ifnet *ifp = fdp->fd_ifp; int len, off, error = 0; int hlen = fin->fin_hlen; struct route iproute; struct sockaddr_in *dst; ip = mtod(m0, struct ip *); /* * Route packet. */ ro = &iproute; bzero((caddr_t)ro, sizeof (*ro)); dst = (struct sockaddr_in *)&ro->ro_dst; dst->sin_family = AF_INET; dst->sin_addr = fdp->fd_ip.s_addr ? fdp->fd_ip : ip->ip_dst; #ifdef __bsdi__ dst->sin_len = sizeof(*dst); #endif #if (BSD >= 199306) && !defined(__NetBSD__) && !defined(__bsdi__) # ifdef RTF_CLONING rtalloc_ign(ro, RTF_CLONING); # else rtalloc_ign(ro, RTF_PRCLONING); # endif #else rtalloc(ro); #endif if (!ifp) { if (!(fin->fin_fr->fr_flags & FR_FASTROUTE)) { error = -2; goto bad; } if (ro->ro_rt == 0 || (ifp = ro->ro_rt->rt_ifp) == 0) { if (in_localaddr(ip->ip_dst)) error = EHOSTUNREACH; else error = ENETUNREACH; goto bad; } if (ro->ro_rt->rt_flags & RTF_GATEWAY) dst = (struct sockaddr_in *)&ro->ro_rt->rt_gateway; } ro->ro_rt->rt_use++; /* * For input packets which are being "fastrouted", they won't * go back through output filtering and miss their chance to get * NAT'd. */ (void) ip_natout(ip, hlen, fin); if (fin->fin_out) ip->ip_sum = 0; /* * If small enough for interface, can just send directly. */ if (ip->ip_len <= ifp->if_mtu) { #ifndef sparc ip->ip_id = htons(ip->ip_id); ip->ip_len = htons(ip->ip_len); ip->ip_off = htons(ip->ip_off); #endif if (!ip->ip_sum) ip->ip_sum = in_cksum(m, hlen); #if BSD >= 199306 error = (*ifp->if_output)(ifp, m, (struct sockaddr *)dst, ro->ro_rt); #else error = (*ifp->if_output)(ifp, m, (struct sockaddr *)dst); #endif goto done; } /* * Too large for interface; fragment if possible. * Must be able to put at least 8 bytes per fragment. */ if (ip->ip_off & IP_DF) { error = EMSGSIZE; goto bad; } len = (ifp->if_mtu - hlen) &~ 7; if (len < 8) { error = EMSGSIZE; goto bad; } { int mhlen, firstlen = len; struct mbuf **mnext = &m->m_act; /* * Loop through length of segment after first fragment, * make new header and copy data of each part and link onto chain. */ m0 = m; mhlen = sizeof (struct ip); for (off = hlen + len; off < ip->ip_len; off += len) { MGET(m, M_DONTWAIT, MT_HEADER); if (m == 0) { error = ENOBUFS; goto bad; } #if BSD >= 199306 m->m_data += max_linkhdr; #else m->m_off = MMAXOFF - hlen; #endif mhip = mtod(m, struct ip *); bcopy((char *)ip, (char *)mhip, sizeof(*ip)); if (hlen > sizeof (struct ip)) { mhlen = ip_optcopy(ip, mhip) + sizeof (struct ip); mhip->ip_hl = mhlen >> 2; } m->m_len = mhlen; mhip->ip_off = ((off - hlen) >> 3) + (ip->ip_off & ~IP_MF); if (ip->ip_off & IP_MF) mhip->ip_off |= IP_MF; if (off + len >= ip->ip_len) len = ip->ip_len - off; else mhip->ip_off |= IP_MF; mhip->ip_len = htons((u_short)(len + mhlen)); m->m_next = m_copy(m0, off, len); if (m->m_next == 0) { error = ENOBUFS; /* ??? */ goto sendorfree; } #ifndef sparc mhip->ip_off = htons((u_short)mhip->ip_off); #endif mhip->ip_sum = 0; mhip->ip_sum = in_cksum(m, mhlen); *mnext = m; mnext = &m->m_act; } /* * Update first fragment by trimming what's been copied out * and updating header, then send each fragment (in order). */ m_adj(m0, hlen + firstlen - ip->ip_len); ip->ip_len = htons((u_short)(hlen + firstlen)); ip->ip_off = htons((u_short)(ip->ip_off | IP_MF)); ip->ip_sum = 0; ip->ip_sum = in_cksum(m0, hlen); sendorfree: for (m = m0; m; m = m0) { m0 = m->m_act; m->m_act = 0; if (error == 0) #if BSD >= 199306 error = (*ifp->if_output)(ifp, m, (struct sockaddr *)dst, ro->ro_rt); #else error = (*ifp->if_output)(ifp, m, (struct sockaddr *)dst); #endif else m_freem(m); } } done: if (ro->ro_rt) { RTFREE(ro->ro_rt); } return; bad: m_freem(m); goto done; }