-/* ip_input.c 1.67 83/05/12 */
-
-#include "../h/param.h"
-#include "../h/systm.h"
-#include "../h/mbuf.h"
-#include "../h/domain.h"
-#include "../h/protosw.h"
-#include "../h/socket.h"
-#include "../h/errno.h"
-#include "../h/time.h"
-#include "../h/kernel.h"
+/*
+ * Copyright (c) 1982, 1986 Regents of the University of California.
+ * All rights reserved. The Berkeley software License Agreement
+ * specifies the terms and conditions for redistribution.
+ *
+ * @(#)ip_input.c 7.6.1.2 (Berkeley) %G%
+ */
+
+#include "param.h"
+#include "systm.h"
+#include "mbuf.h"
+#include "domain.h"
+#include "protosw.h"
+#include "socket.h"
+#include "errno.h"
+#include "time.h"
+#include "kernel.h"
#include "../net/if.h"
#include "../net/route.h"
-#include "../netinet/in.h"
-#include "../netinet/in_pcb.h"
-#include "../netinet/in_systm.h"
-#include "../netinet/ip.h"
-#include "../netinet/ip_var.h"
-#include "../netinet/ip_icmp.h"
-#include "../netinet/tcp.h"
+#include "in.h"
+#include "in_pcb.h"
+#include "in_systm.h"
+#include "in_var.h"
+#include "ip.h"
+#include "ip_var.h"
+#include "ip_icmp.h"
+#include "tcp.h"
u_char ip_protox[IPPROTO_MAX];
int ipqmaxlen = IFQ_MAXLEN;
-struct ifnet *ifinet; /* first inet interface */
+struct in_ifaddr *in_ifaddr; /* first inet address */
+
+/*
+ * We need to save the IP options in case a protocol wants to respond
+ * to an incoming packet over the same route if the packet got here
+ * using IP source routing. This allows connection establishment and
+ * maintenance when the remote end is on a network that is not known
+ * to us.
+ */
+int ip_nhops = 0;
+static struct ip_srcrt {
+ char nop; /* one NOP to align */
+ char srcopt[IPOPT_OFFSET + 1]; /* OPTVAL, OLEN and OFFSET */
+ struct in_addr route[MAX_IPOPTLEN];
+} ip_srcrt;
/*
* IP initialization: fill in IP protocol switch table.
register struct protosw *pr;
register int i;
- pr = pffindproto(PF_INET, IPPROTO_RAW);
+ pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW);
if (pr == 0)
panic("ip_init");
for (i = 0; i < IPPROTO_MAX; i++)
ip_protox[i] = pr - inetsw;
for (pr = inetdomain.dom_protosw;
- pr <= inetdomain.dom_protoswNPROTOSW; pr++)
- if (pr->pr_family == PF_INET &&
+ pr < inetdomain.dom_protoswNPROTOSW; pr++)
+ if (pr->pr_domain->dom_family == PF_INET &&
pr->pr_protocol && pr->pr_protocol != IPPROTO_RAW)
ip_protox[pr->pr_protocol] = pr - inetsw;
ipq.next = ipq.prev = &ipq;
ip_id = time.tv_sec & 0xffff;
ipintrq.ifq_maxlen = ipqmaxlen;
- ifinet = if_ifwithaf(AF_INET);
}
u_char ipcksum = 1;
struct ip *ip_reass();
struct sockaddr_in ipaddr = { AF_INET };
+struct route ipforward_rt;
/*
* Ip input routine. Checksum and byte swap header. If fragmented
struct mbuf *m0;
register int i;
register struct ipq *fp;
+ register struct in_ifaddr *ia;
+ struct ifnet *ifp;
int hlen, s;
next:
* in first mbuf.
*/
s = splimp();
- IF_DEQUEUE(&ipintrq, m);
+ IF_DEQUEUEIF(&ipintrq, m, ifp);
splx(s);
if (m == 0)
return;
+ /*
+ * If no IP addresses have been set yet but the interfaces
+ * are receiving, can't do anything with incoming packets yet.
+ */
+ if (in_ifaddr == NULL)
+ goto bad;
+ ipstat.ips_total++;
if ((m->m_off > MMAXOFF || m->m_len < sizeof (struct ip)) &&
(m = m_pullup(m, sizeof (struct ip))) == 0) {
ipstat.ips_toosmall++;
goto next;
}
ip = mtod(m, struct ip *);
- if ((hlen = ip->ip_hl << 2) > m->m_len) {
+ hlen = ip->ip_hl << 2;
+ if (hlen < sizeof(struct ip)) { /* minimum header length */
+ ipstat.ips_badhlen++;
+ goto bad;
+ }
+ if (hlen > m->m_len) {
if ((m = m_pullup(m, hlen)) == 0) {
ipstat.ips_badhlen++;
goto next;
* Trim mbufs if longer than we expect.
* Drop packet if shorter than we expect.
*/
- i = -ip->ip_len;
+ i = -(u_short)ip->ip_len;
m0 = m;
for (;;) {
i += m->m_len;
if (i != 0) {
if (i < 0) {
ipstat.ips_tooshort++;
+ m = m0;
goto bad;
}
if (i <= m->m_len)
* Process options and, if not destined for us,
* ship it on. ip_dooptions returns 1 when an
* error was detected (causing an icmp message
- * to be sent).
+ * to be sent and the original packet to be freed).
*/
- if (hlen > sizeof (struct ip) && ip_dooptions(ip))
+ ip_nhops = 0; /* for source routed packets */
+ if (hlen > sizeof (struct ip) && ip_dooptions(ip, ifp))
goto next;
/*
- * Fast check on the first internet
- * interface in the list.
+ * Check our list of addresses, to see if the packet is for us.
*/
- if (ifinet) {
- struct sockaddr_in *sin;
+ for (ia = in_ifaddr; ia; ia = ia->ia_next) {
+#define satosin(sa) ((struct sockaddr_in *)(sa))
- sin = (struct sockaddr_in *)&ifinet->if_addr;
- if (sin->sin_addr.s_addr == ip->ip_dst.s_addr)
- goto ours;
- sin = (struct sockaddr_in *)&ifinet->if_broadaddr;
- if ((ifinet->if_flags & IFF_BROADCAST) &&
- sin->sin_addr.s_addr == ip->ip_dst.s_addr)
+ if (IA_SIN(ia)->sin_addr.s_addr == ip->ip_dst.s_addr)
goto ours;
+ if (
+#ifdef DIRECTED_BROADCAST
+ ia->ia_ifp == ifp &&
+#endif
+ (ia->ia_ifp->if_flags & IFF_BROADCAST)) {
+ u_long t;
+
+ if (satosin(&ia->ia_broadaddr)->sin_addr.s_addr ==
+ ip->ip_dst.s_addr)
+ goto ours;
+ if (ip->ip_dst.s_addr == ia->ia_netbroadcast.s_addr)
+ goto ours;
+ /*
+ * Look for all-0's host part (old broadcast addr),
+ * either for subnet or net.
+ */
+ t = ntohl(ip->ip_dst.s_addr);
+ if (t == ia->ia_subnet)
+ goto ours;
+ if (t == ia->ia_net)
+ goto ours;
+ }
}
-/* BEGIN GROT */
-#include "nd.h"
-#if NND > 0
+ if (ip->ip_dst.s_addr == (u_long)INADDR_BROADCAST)
+ goto ours;
+ if (ip->ip_dst.s_addr == INADDR_ANY)
+ goto ours;
+
/*
- * Diskless machines don't initially know
- * their address, so take packets from them
- * if we're acting as a network disk server.
+ * Not for us; forward if possible and desirable.
*/
- if (ip->ip_dst.s_addr == INADDR_ANY &&
- (in_netof(ip->ip_src) == INADDR_ANY &&
- in_lnaof(ip->ip_src) != INADDR_ANY))
- goto ours;
-#endif
-/* END GROT */
- ipaddr.sin_addr = ip->ip_dst;
- if (if_ifwithaddr((struct sockaddr *)&ipaddr) == 0) {
- ip_forward(ip);
- goto next;
- }
+ ip_forward(ip, ifp);
+ goto next;
ours:
/*
* attempt reassembly; if it succeeds, proceed.
*/
if (((struct ipasfrag *)ip)->ipf_mff || ip->ip_off) {
+ ipstat.ips_fragments++;
ip = ip_reass((struct ipasfrag *)ip, fp);
if (ip == 0)
goto next;
- hlen = ip->ip_hl << 2;
m = dtom(ip);
} else
if (fp)
/*
* Switch out to protocol's input routine.
*/
- (*inetsw[ip_protox[ip->ip_p]].pr_input)(m);
+ (*inetsw[ip_protox[ip->ip_p]].pr_input)(m, ifp);
goto next;
bad:
m_freem(m);
* If first fragment to arrive, create a reassembly queue.
*/
if (fp == 0) {
- if ((t = m_get(M_WAIT, MT_FTABLE)) == NULL)
+ if ((t = m_get(M_DONTWAIT, MT_FTABLE)) == NULL)
goto dropfrag;
fp = mtod(t, struct ipq *);
insque(fp, &ipq);
remque(fp);
(void) m_free(dtom(fp));
m = dtom(ip);
- m->m_len += sizeof (struct ipasfrag);
- m->m_off -= sizeof (struct ipasfrag);
+ m->m_len += (ip->ip_hl << 2);
+ m->m_off -= (ip->ip_hl << 2);
return ((struct ip *)ip);
dropfrag:
+ ipstat.ips_fragdropped++;
m_freem(m);
return (0);
}
while (fp != &ipq) {
--fp->ipq_ttl;
fp = fp->next;
- if (fp->prev->ipq_ttl == 0)
+ if (fp->prev->ipq_ttl == 0) {
+ ipstat.ips_fragtimeout++;
ip_freef(fp->prev);
+ }
}
splx(s);
}
ip_drain()
{
- while (ipq.next != &ipq)
+ while (ipq.next != &ipq) {
+ ipstat.ips_fragdropped++;
ip_freef(ipq.next);
+ }
}
+extern struct in_ifaddr *ifptoia();
+struct in_ifaddr *ip_rtaddr();
+
/*
* Do option processing on a datagram,
* possibly discarding it if bad options
* are encountered.
*/
-ip_dooptions(ip)
- struct ip *ip;
+ip_dooptions(ip, ifp)
+ register struct ip *ip;
+ struct ifnet *ifp;
{
register u_char *cp;
- int opt, optlen, cnt, code, type;
- struct in_addr *sin;
+ int opt, optlen, cnt, off, code, type = ICMP_PARAMPROB;
register struct ip_timestamp *ipt;
- register struct ifnet *ifp;
- struct in_addr t;
+ register struct in_ifaddr *ia;
+ struct in_addr *sin;
+ n_time ntime;
cp = (u_char *)(ip + 1);
cnt = (ip->ip_hl << 2) - sizeof (struct ip);
for (; cnt > 0; cnt -= optlen, cp += optlen) {
- opt = cp[0];
+ opt = cp[IPOPT_OPTVAL];
if (opt == IPOPT_EOL)
break;
if (opt == IPOPT_NOP)
optlen = 1;
- else
- optlen = cp[1];
+ else {
+ optlen = cp[IPOPT_OLEN];
+ if (optlen <= 0 || optlen > cnt) {
+ code = &cp[IPOPT_OLEN] - (u_char *)ip;
+ goto bad;
+ }
+ }
switch (opt) {
default:
*/
case IPOPT_LSRR:
case IPOPT_SSRR:
- if (cp[2] < 4 || cp[2] > optlen - (sizeof (long) - 1))
- break;
- sin = (struct in_addr *)(cp + cp[2]);
- ipaddr.sin_addr = *sin;
- ifp = if_ifwithaddr((struct sockaddr *)&ipaddr);
- type = ICMP_UNREACH, code = ICMP_UNREACH_SRCFAIL;
- if (ifp == 0) {
- if (opt == IPOPT_SSRR)
+ if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) {
+ code = &cp[IPOPT_OFFSET] - (u_char *)ip;
+ goto bad;
+ }
+ ipaddr.sin_addr = ip->ip_dst;
+ ia = (struct in_ifaddr *)
+ ifa_ifwithaddr((struct sockaddr *)&ipaddr);
+ if (ia == 0) {
+ if (opt == IPOPT_SSRR) {
+ type = ICMP_UNREACH;
+ code = ICMP_UNREACH_SRCFAIL;
goto bad;
+ }
+ /*
+ * Loose routing, and not at next destination
+ * yet; nothing to do except forward.
+ */
break;
}
- t = ip->ip_dst; ip->ip_dst = *sin; *sin = t;
- cp[2] += 4;
- if (cp[2] > optlen - (sizeof (long) - 1))
+ off--; /* 0 origin */
+ if (off > optlen - sizeof(struct in_addr)) {
+ /*
+ * End of source route. Should be for us.
+ */
+ save_rte(cp, ip->ip_src);
break;
- ip->ip_dst = sin[1];
- if (opt == IPOPT_SSRR &&
- if_ifonnetof(in_netof(ip->ip_dst)) == 0)
+ }
+ /*
+ * locate outgoing interface
+ */
+ bcopy((caddr_t)(cp + off), (caddr_t)&ipaddr.sin_addr,
+ sizeof(ipaddr.sin_addr));
+ if ((opt == IPOPT_SSRR &&
+ in_iaonnetof(in_netof(ipaddr.sin_addr)) == 0) ||
+ (ia = ip_rtaddr(ipaddr.sin_addr)) == 0) {
+ type = ICMP_UNREACH;
+ code = ICMP_UNREACH_SRCFAIL;
goto bad;
+ }
+ ip->ip_dst = ipaddr.sin_addr;
+ bcopy((caddr_t)&(IA_SIN(ia)->sin_addr),
+ (caddr_t)(cp + off), sizeof(struct in_addr));
+ cp[IPOPT_OFFSET] += sizeof(struct in_addr);
+ break;
+
+ case IPOPT_RR:
+ if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) {
+ code = &cp[IPOPT_OFFSET] - (u_char *)ip;
+ goto bad;
+ }
+ /*
+ * If no space remains, ignore.
+ */
+ off--; /* 0 origin */
+ if (off > optlen - sizeof(struct in_addr))
+ break;
+ bcopy((caddr_t)(&ip->ip_dst), (caddr_t)&ipaddr.sin_addr,
+ sizeof(ipaddr.sin_addr));
+ /*
+ * locate outgoing interface
+ */
+ if ((ia = ip_rtaddr(ipaddr.sin_addr)) == 0) {
+ type = ICMP_UNREACH;
+ code = ICMP_UNREACH_HOST;
+ goto bad;
+ }
+ bcopy((caddr_t)&(IA_SIN(ia)->sin_addr),
+ (caddr_t)(cp + off), sizeof(struct in_addr));
+ cp[IPOPT_OFFSET] += sizeof(struct in_addr);
break;
case IPOPT_TS:
code = cp - (u_char *)ip;
- type = ICMP_PARAMPROB;
ipt = (struct ip_timestamp *)cp;
if (ipt->ipt_len < 5)
goto bad;
goto bad;
break;
}
- sin = (struct in_addr *)(cp+cp[2]);
+ sin = (struct in_addr *)(cp + ipt->ipt_ptr - 1);
switch (ipt->ipt_flg) {
case IPOPT_TS_TSONLY:
break;
case IPOPT_TS_TSANDADDR:
- if (ipt->ipt_ptr + 8 > ipt->ipt_len)
+ if (ipt->ipt_ptr + sizeof(n_time) +
+ sizeof(struct in_addr) > ipt->ipt_len)
goto bad;
- if (ifinet == 0)
- goto bad; /* ??? */
- *sin++ = ((struct sockaddr_in *)&ifinet->if_addr)->sin_addr;
+ ia = ifptoia(ifp);
+ bcopy((caddr_t)&IA_SIN(ia)->sin_addr,
+ (caddr_t)sin, sizeof(struct in_addr));
+ ipt->ipt_ptr += sizeof(struct in_addr);
break;
case IPOPT_TS_PRESPEC:
- ipaddr.sin_addr = *sin;
- if (if_ifwithaddr((struct sockaddr *)&ipaddr) == 0)
- continue;
- if (ipt->ipt_ptr + 8 > ipt->ipt_len)
+ if (ipt->ipt_ptr + sizeof(n_time) +
+ sizeof(struct in_addr) > ipt->ipt_len)
goto bad;
- ipt->ipt_ptr += 4;
+ bcopy((caddr_t)sin, (caddr_t)&ipaddr.sin_addr,
+ sizeof(struct in_addr));
+ if (ifa_ifwithaddr((struct sockaddr *)&ipaddr) == 0)
+ continue;
+ ipt->ipt_ptr += sizeof(struct in_addr);
break;
default:
goto bad;
}
- *(n_time *)sin = iptime();
- ipt->ipt_ptr += 4;
+ ntime = iptime();
+ bcopy((caddr_t)&ntime, (caddr_t)cp + ipt->ipt_ptr - 1,
+ sizeof(n_time));
+ ipt->ipt_ptr += sizeof(n_time);
}
}
return (0);
bad:
- icmp_error(ip, type, code);
+ icmp_error(ip, type, code, ifp);
return (1);
}
+/*
+ * Given address of next destination (final or next hop),
+ * return internet address info of interface to be used to get there.
+ */
+struct in_ifaddr *
+ip_rtaddr(dst)
+ struct in_addr dst;
+{
+ register struct sockaddr_in *sin;
+ register struct in_ifaddr *ia;
+
+ sin = (struct sockaddr_in *) &ipforward_rt.ro_dst;
+
+ if (ipforward_rt.ro_rt == 0 || dst.s_addr != sin->sin_addr.s_addr) {
+ if (ipforward_rt.ro_rt) {
+ RTFREE(ipforward_rt.ro_rt);
+ ipforward_rt.ro_rt = 0;
+ }
+ sin->sin_family = AF_INET;
+ sin->sin_addr = dst;
+
+ rtalloc(&ipforward_rt);
+ }
+ if (ipforward_rt.ro_rt == 0)
+ return ((struct in_ifaddr *)0);
+ /*
+ * Find address associated with outgoing interface.
+ */
+ for (ia = in_ifaddr; ia; ia = ia->ia_next)
+ if (ia->ia_ifp == ipforward_rt.ro_rt->rt_ifp)
+ break;
+ return (ia);
+}
+
+/*
+ * Save incoming source route for use in replies,
+ * to be picked up later by ip_srcroute if the receiver is interested.
+ */
+save_rte(option, dst)
+ u_char *option;
+ struct in_addr dst;
+{
+ unsigned olen;
+ extern ipprintfs;
+
+ olen = option[IPOPT_OLEN];
+ if (olen > sizeof(ip_srcrt) - 1) {
+ if (ipprintfs)
+ printf("save_rte: olen %d\n", olen);
+ return;
+ }
+ bcopy((caddr_t)option, (caddr_t)ip_srcrt.srcopt, olen);
+ ip_nhops = (olen - IPOPT_OFFSET - 1) / sizeof(struct in_addr);
+ ip_srcrt.route[ip_nhops++] = dst;
+}
+
+/*
+ * Retrieve incoming source route for use in replies,
+ * in the same form used by setsockopt.
+ * The first hop is placed before the options, will be removed later.
+ */
+struct mbuf *
+ip_srcroute()
+{
+ register struct in_addr *p, *q;
+ register struct mbuf *m;
+
+ if (ip_nhops == 0)
+ return ((struct mbuf *)0);
+ m = m_get(M_DONTWAIT, MT_SOOPTS);
+ if (m == 0)
+ return ((struct mbuf *)0);
+ m->m_len = ip_nhops * sizeof(struct in_addr) + IPOPT_OFFSET + 1 + 1;
+
+ /*
+ * First save first hop for return route
+ */
+ p = &ip_srcrt.route[ip_nhops - 1];
+ *(mtod(m, struct in_addr *)) = *p--;
+
+ /*
+ * Copy option fields and padding (nop) to mbuf.
+ */
+ ip_srcrt.nop = IPOPT_NOP;
+ bcopy((caddr_t)&ip_srcrt, mtod(m, caddr_t) + sizeof(struct in_addr),
+ IPOPT_OFFSET + 1 + 1);
+ q = (struct in_addr *)(mtod(m, caddr_t) +
+ sizeof(struct in_addr) + IPOPT_OFFSET + 1 + 1);
+ /*
+ * Record return path as an IP source route,
+ * reversing the path (pointers are now aligned).
+ */
+ while (p >= ip_srcrt.route)
+ *q++ = *p--;
+ return (m);
+}
+
/*
* Strip out IP options, at higher
* level protocol in the kernel.
{
register int i;
register struct mbuf *m;
+ register caddr_t opts;
int olen;
olen = (ip->ip_hl<<2) - sizeof (struct ip);
m = dtom(ip);
- ip++;
+ opts = (caddr_t)(ip + 1);
if (mopt) {
mopt->m_len = olen;
mopt->m_off = MMINOFF;
- bcopy((caddr_t)ip, mtod(m, caddr_t), (unsigned)olen);
+ bcopy(opts, mtod(mopt, caddr_t), (unsigned)olen);
}
i = m->m_len - (sizeof (struct ip) + olen);
- bcopy((caddr_t)ip+olen, (caddr_t)ip, (unsigned)i);
+ bcopy(opts + olen, opts, (unsigned)i);
m->m_len -= olen;
+ ip->ip_hl = sizeof(struct ip) >> 2;
}
-u_char inetctlerrmap[] = {
- ECONNABORTED, ECONNABORTED, 0, 0,
- 0, 0,
- EHOSTDOWN, EHOSTUNREACH, ENETUNREACH, EHOSTUNREACH,
- ECONNREFUSED, ECONNREFUSED, EMSGSIZE, 0,
- 0, 0, 0, 0
+u_char inetctlerrmap[PRC_NCMDS] = {
+ 0, 0, 0, 0,
+ 0, 0, EHOSTDOWN, EHOSTUNREACH,
+ ENETUNREACH, EHOSTUNREACH, ECONNREFUSED, ECONNREFUSED,
+ EMSGSIZE, EHOSTUNREACH, 0, 0,
+ 0, 0, 0, 0,
+ ENOPROTOOPT
};
-ip_ctlinput(cmd, arg)
- int cmd;
- caddr_t arg;
-{
- struct in_addr *in;
- int tcp_abort(), udp_abort();
- extern struct inpcb tcb, udb;
-
- if (cmd < 0 || cmd > PRC_NCMDS)
- return;
- if (inetctlerrmap[cmd] == 0)
- return; /* XXX */
- if (cmd == PRC_IFDOWN)
- in = &((struct sockaddr_in *)arg)->sin_addr;
- else if (cmd == PRC_HOSTDEAD || cmd == PRC_HOSTUNREACH)
- in = (struct in_addr *)arg;
- else
- in = &((struct icmp *)arg)->icmp_ip.ip_dst;
-/* THIS IS VERY QUESTIONABLE, SHOULD HIT ALL PROTOCOLS */
- in_pcbnotify(&tcb, in, (int)inetctlerrmap[cmd], tcp_abort);
- in_pcbnotify(&udb, in, (int)inetctlerrmap[cmd], udp_abort);
-}
-
+#ifndef IPFORWARDING
+#define IPFORWARDING 1
+#endif
+#ifndef IPSENDREDIRECTS
+#define IPSENDREDIRECTS 1
+#endif
int ipprintfs = 0;
-int ipforwarding = 1;
+int ipforwarding = IPFORWARDING;
+extern int in_interfaces;
+int ipsendredirects = IPSENDREDIRECTS;
+
/*
* Forward a packet. If some error occurs return the sender
- * and icmp packet. Note we can't always generate a meaningful
- * icmp message because icmp doesn't have a large enough repetoire
+ * an icmp packet. Note we can't always generate a meaningful
+ * icmp message because icmp doesn't have a large enough repertoire
* of codes and types.
+ *
+ * If not forwarding (possibly because we have only a single external
+ * network), just drop the packet. This could be confusing if ipforwarding
+ * was zero but some routing protocol was advancing us as a gateway
+ * to somewhere. However, we must let the routing protocol deal with that.
*/
-ip_forward(ip)
+ip_forward(ip, ifp)
register struct ip *ip;
+ struct ifnet *ifp;
{
- register int error, type, code;
- struct mbuf *mopt, *mcopy;
+ register int error, type = 0, code;
+ register struct sockaddr_in *sin;
+ struct mbuf *mcopy;
+ struct in_addr dest;
+ dest.s_addr = 0;
if (ipprintfs)
printf("forward: src %x dst %x ttl %x\n", ip->ip_src,
ip->ip_dst, ip->ip_ttl);
- if (ipforwarding == 0) {
- /* can't tell difference between net and host */
+ ip->ip_id = htons(ip->ip_id);
+ if (ipforwarding == 0 || in_interfaces <= 1) {
+ ipstat.ips_cantforward++;
+#ifdef GATEWAY
type = ICMP_UNREACH, code = ICMP_UNREACH_NET;
goto sendicmp;
+#else
+ m_freem(dtom(ip));
+ return;
+#endif
}
- if (ip->ip_ttl < IPTTLDEC) {
+ if (ip->ip_ttl <= IPTTLDEC) {
type = ICMP_TIMXCEED, code = ICMP_TIMXCEED_INTRANS;
goto sendicmp;
}
ip->ip_ttl -= IPTTLDEC;
- mopt = m_get(M_DONTWAIT, MT_DATA);
- if (mopt == NULL) {
- m_freem(dtom(ip));
- return;
- }
/*
* Save at most 64 bytes of the packet in case
* we need to generate an ICMP message to the src.
*/
- mcopy = m_copy(dtom(ip), 0, imin(ip->ip_len, 64));
- ip_stripoptions(ip, mopt);
+ mcopy = m_copy(dtom(ip), 0, imin((int)ip->ip_len, 64));
+
+ sin = (struct sockaddr_in *)&ipforward_rt.ro_dst;
+ if (ipforward_rt.ro_rt == 0 ||
+ ip->ip_dst.s_addr != sin->sin_addr.s_addr) {
+ if (ipforward_rt.ro_rt) {
+ RTFREE(ipforward_rt.ro_rt);
+ ipforward_rt.ro_rt = 0;
+ }
+ sin->sin_family = AF_INET;
+ sin->sin_addr = ip->ip_dst;
- error = ip_output(dtom(ip), mopt, (struct route *)0, IP_FORWARDING);
- if (error == 0) {
+ rtalloc(&ipforward_rt);
+ }
+ /*
+ * If forwarding packet using same interface that it came in on,
+ * perhaps should send a redirect to sender to shortcut a hop.
+ * Only send redirect if source is sending directly to us,
+ * and if packet was not source routed (or has any options).
+ * Also, don't send redirect if forwarding using a default route
+ * or a route modfied by a redirect.
+ */
+#define satosin(sa) ((struct sockaddr_in *)(sa))
+ if (ipforward_rt.ro_rt && ipforward_rt.ro_rt->rt_ifp == ifp &&
+ (ipforward_rt.ro_rt->rt_flags & RTF_DYNAMIC) == 0 &&
+ satosin(&ipforward_rt.ro_rt->rt_dst)->sin_addr.s_addr != 0 &&
+ ipsendredirects && ip->ip_hl == (sizeof(struct ip) >> 2)) {
+ struct in_ifaddr *ia;
+ u_long src = ntohl(ip->ip_src.s_addr);
+ u_long dst = ntohl(ip->ip_dst.s_addr);
+
+ if ((ia = ifptoia(ifp)) &&
+ (src & ia->ia_subnetmask) == ia->ia_subnet) {
+ if (ipforward_rt.ro_rt->rt_flags & RTF_GATEWAY)
+ dest = satosin(&ipforward_rt.ro_rt->rt_gateway)->sin_addr;
+ else
+ dest = ip->ip_dst;
+ /*
+ * If the destination is reached by a route to host,
+ * is on a subnet of a local net, or is directly
+ * on the attached net (!), use host redirect.
+ * (We may be the correct first hop for other subnets.)
+ */
+ type = ICMP_REDIRECT;
+ code = ICMP_REDIRECT_NET;
+ if ((ipforward_rt.ro_rt->rt_flags & RTF_HOST) ||
+ (ipforward_rt.ro_rt->rt_flags & RTF_GATEWAY) == 0)
+ code = ICMP_REDIRECT_HOST;
+ else for (ia = in_ifaddr; ia = ia->ia_next; )
+ if ((dst & ia->ia_netmask) == ia->ia_net) {
+ if (ia->ia_subnetmask != ia->ia_netmask)
+ code = ICMP_REDIRECT_HOST;
+ break;
+ }
+ if (ipprintfs)
+ printf("redirect (%d) to %x\n", code, dest);
+ }
+ }
+
+ error = ip_output(dtom(ip), (struct mbuf *)0, &ipforward_rt,
+ IP_FORWARDING);
+ if (error)
+ ipstat.ips_cantforward++;
+ else if (type)
+ ipstat.ips_redirectsent++;
+ else {
if (mcopy)
m_freem(mcopy);
+ ipstat.ips_forward++;
return;
}
if (mcopy == NULL)
return;
ip = mtod(mcopy, struct ip *);
- type = ICMP_UNREACH, code = 0; /* need ``undefined'' */
+ type = ICMP_UNREACH;
switch (error) {
+ case 0: /* forwarded, but need redirect */
+ type = ICMP_REDIRECT;
+ /* code set above */
+ break;
+
case ENETUNREACH:
case ENETDOWN:
code = ICMP_UNREACH_NET;
break;
}
sendicmp:
- icmp_error(ip, type, code);
+ icmp_error(ip, type, code, ifp, dest);
}