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-rw-r--r--sys/contrib/ipfilter/netinet/ip_fil.c885
1 files changed, 885 insertions, 0 deletions
diff --git a/sys/contrib/ipfilter/netinet/ip_fil.c b/sys/contrib/ipfilter/netinet/ip_fil.c
new file mode 100644
index 0000000..7a24434
--- /dev/null
+++ b/sys/contrib/ipfilter/netinet/ip_fil.c
@@ -0,0 +1,885 @@
+/*
+ * (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 2.0.1.5 1997/01/29 13:41:45 darrenr Exp $";
+#endif
+
+#include <sys/errno.h>
+#include <sys/types.h>
+#include <sys/param.h>
+#include <sys/file.h>
+#include <sys/ioctl.h>
+#include <sys/systm.h>
+#include <sys/uio.h>
+#include <sys/mbuf.h>
+#include <sys/protosw.h>
+#include <sys/socket.h>
+
+#include <net/if.h>
+#ifdef sun
+#include <net/af.h>
+#endif
+#include <net/route.h>
+#include <netinet/in.h>
+#include <netinet/in_var.h>
+#include <netinet/in_systm.h>
+#include <netinet/ip.h>
+#include <netinet/ip_var.h>
+#include <netinet/tcp.h>
+#include <netinet/udp.h>
+#include <netinet/tcpip.h>
+#include <netinet/ip_icmp.h>
+#include <syslog.h>
+#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)();
+
+#if _BSDI_VERSION >= 199501
+# include <sys/device.h>
+# include <sys/conf.h>
+
+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;
+#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;
+}
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