X-Git-Url: https://git.subgeniuskitty.com/unix-history/.git/blobdiff_plain/b2a3d55917a26470f77b73231e70f736b9ba615f..7985f2abad4958a0f6ef93ad1df40487ba6ff5a8:/usr/src/sys/netinet/ip_input.c

diff --git a/usr/src/sys/netinet/ip_input.c b/usr/src/sys/netinet/ip_input.c
index e971ccc9e4..c0488df76c 100644
--- a/usr/src/sys/netinet/ip_input.c
+++ b/usr/src/sys/netinet/ip_input.c
@@ -1,9 +1,20 @@
 /*
- * Copyright (c) 1982 Regents of the University of California.
- * All rights reserved.  The Berkeley software License Agreement
- * specifies the terms and conditions for redistribution.
+ * Copyright (c) 1982, 1986 Regents of the University of California.
+ * All rights reserved.
  *
- *	@(#)ip_input.c	6.17 (Berkeley) %G%
+ * Redistribution and use in source and binary forms are permitted
+ * provided that the above copyright notice and this paragraph are
+ * duplicated in all such forms and that any documentation,
+ * advertising materials, and other materials related to such
+ * distribution and use acknowledge that the software was developed
+ * by the University of California, Berkeley.  The name of the
+ * University may not be used to endorse or promote products derived
+ * from this software without specific prior written permission.
+ * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
+ * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
+ *
+ *	@(#)ip_input.c	7.10 (Berkeley) %G%
  */
 
 #include "param.h"
@@ -224,43 +235,53 @@ next:
 
 ours:
 	/*
-	 * Look for queue of fragments
-	 * of this datagram.
+	 * If offset or IP_MF are set, must reassemble.
+	 * Otherwise, nothing need be done.
+	 * (We could look in the reassembly queue to see
+	 * if the packet was previously fragmented,
+	 * but it's not worth the time; just let them time out.)
 	 */
-	for (fp = ipq.next; fp != &ipq; fp = fp->next)
-		if (ip->ip_id == fp->ipq_id &&
-		    ip->ip_src.s_addr == fp->ipq_src.s_addr &&
-		    ip->ip_dst.s_addr == fp->ipq_dst.s_addr &&
-		    ip->ip_p == fp->ipq_p)
-			goto found;
-	fp = 0;
+	if (ip->ip_off &~ IP_DF) {
+		/*
+		 * Look for queue of fragments
+		 * of this datagram.
+		 */
+		for (fp = ipq.next; fp != &ipq; fp = fp->next)
+			if (ip->ip_id == fp->ipq_id &&
+			    ip->ip_src.s_addr == fp->ipq_src.s_addr &&
+			    ip->ip_dst.s_addr == fp->ipq_dst.s_addr &&
+			    ip->ip_p == fp->ipq_p)
+				goto found;
+		fp = 0;
 found:
 
-	/*
-	 * Adjust ip_len to not reflect header,
-	 * set ip_mff if more fragments are expected,
-	 * convert offset of this to bytes.
-	 */
-	ip->ip_len -= hlen;
-	((struct ipasfrag *)ip)->ipf_mff = 0;
-	if (ip->ip_off & IP_MF)
-		((struct ipasfrag *)ip)->ipf_mff = 1;
-	ip->ip_off <<= 3;
+		/*
+		 * Adjust ip_len to not reflect header,
+		 * set ip_mff if more fragments are expected,
+		 * convert offset of this to bytes.
+		 */
+		ip->ip_len -= hlen;
+		((struct ipasfrag *)ip)->ipf_mff = 0;
+		if (ip->ip_off & IP_MF)
+			((struct ipasfrag *)ip)->ipf_mff = 1;
+		ip->ip_off <<= 3;
 
-	/*
-	 * If datagram marked as having more fragments
-	 * or if this is not the first fragment,
-	 * 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;
-		m = dtom(ip);
+		/*
+		 * If datagram marked as having more fragments
+		 * or if this is not the first fragment,
+		 * 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;
+			m = dtom(ip);
+		} else
+			if (fp)
+				ip_freef(fp);
 	} else
-		if (fp)
-			ip_freef(fp);
+		ip->ip_len -= hlen;
 
 	/*
 	 * Switch out to protocol's input routine.
@@ -300,7 +321,7 @@ ip_reass(ip, fp)
 	 * 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);
@@ -488,6 +509,7 @@ ip_drain()
 	}
 }
 
+extern struct in_ifaddr *ifptoia();
 struct in_ifaddr *ip_rtaddr();
 
 /*
@@ -567,7 +589,7 @@ ip_dooptions(ip, ifp)
 			/*
 			 * locate outgoing interface
 			 */
-			bcopy(cp + off, (caddr_t)&ipaddr.sin_addr,
+			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) ||
@@ -577,8 +599,8 @@ ip_dooptions(ip, ifp)
 				goto bad;
 			}
 			ip->ip_dst = ipaddr.sin_addr;
-			bcopy(&(IA_SIN(ia)->sin_addr), cp + off,
-				sizeof(struct in_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;
 
@@ -593,18 +615,18 @@ ip_dooptions(ip, ifp)
 			off--;			/* 0 origin */
 			if (off > optlen - sizeof(struct in_addr))
 				break;
-			bcopy(cp + off, (caddr_t)ipaddr.sin_addr,
+			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_SRCFAIL;
+				code = ICMP_UNREACH_HOST;
 				goto bad;
 			}
-			bcopy(&(IA_SIN(ia)->sin_addr), cp + off,
-				sizeof(struct in_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;
 
@@ -618,7 +640,7 @@ ip_dooptions(ip, ifp)
 					goto bad;
 				break;
 			}
-			sin = (struct in_addr *)(cp+cp[IPOPT_OFFSET]-1);
+			sin = (struct in_addr *)(cp + ipt->ipt_ptr - 1);
 			switch (ipt->ipt_flg) {
 
 			case IPOPT_TS_TSONLY:
@@ -628,21 +650,20 @@ ip_dooptions(ip, ifp)
 				if (ipt->ipt_ptr + sizeof(n_time) +
 				    sizeof(struct in_addr) > ipt->ipt_len)
 					goto bad;
-				if (in_ifaddr == 0)
-					goto bad;	/* ??? */
-				bcopy((caddr_t)&IA_SIN(in_ifaddr)->sin_addr,
+				ia = ifptoia(ifp);
+				bcopy((caddr_t)&IA_SIN(ia)->sin_addr,
 				    (caddr_t)sin, sizeof(struct in_addr));
-				sin++;
+				ipt->ipt_ptr += sizeof(struct in_addr);
 				break;
 
 			case IPOPT_TS_PRESPEC:
+				if (ipt->ipt_ptr + sizeof(n_time) +
+				    sizeof(struct in_addr) > ipt->ipt_len)
+					goto bad;
 				bcopy((caddr_t)sin, (caddr_t)&ipaddr.sin_addr,
 				    sizeof(struct in_addr));
 				if (ifa_ifwithaddr((struct sockaddr *)&ipaddr) == 0)
 					continue;
-				if (ipt->ipt_ptr + sizeof(n_time) +
-				    sizeof(struct in_addr) > ipt->ipt_len)
-					goto bad;
 				ipt->ipt_ptr += sizeof(struct in_addr);
 				break;
 
@@ -650,7 +671,8 @@ ip_dooptions(ip, ifp)
 				goto bad;
 			}
 			ntime = iptime();
-			bcopy((caddr_t)&ntime, (caddr_t)sin, sizeof(n_time));
+			bcopy((caddr_t)&ntime, (caddr_t)cp + ipt->ipt_ptr - 1,
+			    sizeof(n_time));
 			ipt->ipt_ptr += sizeof(n_time);
 		}
 	}
@@ -699,10 +721,10 @@ ip_rtaddr(dst)
  * to be picked up later by ip_srcroute if the receiver is interested.
  */
 save_rte(option, dst)
-	caddr_t option;
+	u_char *option;
 	struct in_addr dst;
 {
-	int olen;
+	unsigned olen;
 	extern ipprintfs;
 
 	olen = option[IPOPT_OLEN];
@@ -711,7 +733,7 @@ save_rte(option, dst)
 			printf("save_rte: olen %d\n", olen);
 		return;
 	}
-	bcopy(option, (caddr_t)ip_srcrt.srcopt, olen);
+	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;
 }
@@ -729,7 +751,9 @@ ip_srcroute()
 
 	if (ip_nhops == 0)
 		return ((struct mbuf *)0);
-	m = m_get(M_WAIT, MT_SOOPTS);
+	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;
 
 	/*
@@ -809,6 +833,11 @@ int	ipsendredirects = IPSENDREDIRECTS;
  * 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, ifp)
 	register struct ip *ip;
@@ -819,19 +848,22 @@ ip_forward(ip, ifp)
 	struct mbuf *mcopy;
 	struct in_addr dest;
 
-#ifdef lint
 	dest.s_addr = 0;
-#endif
 	if (ipprintfs)
 		printf("forward: src %x dst %x ttl %x\n", ip->ip_src,
 			ip->ip_dst, ip->ip_ttl);
 	ip->ip_id = htons(ip->ip_id);
 	if (ipforwarding == 0 || in_interfaces <= 1) {
-		/* can't tell difference between net and host */
+		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;
 	}
@@ -841,7 +873,7 @@ ip_forward(ip, ifp)
 	 * 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));
+	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 ||
@@ -860,11 +892,15 @@ ip_forward(ip, ifp)
 	 * 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;
-		extern struct in_ifaddr *ifptoia();
 		u_long src = ntohl(ip->ip_src.s_addr);
 		u_long dst = ntohl(ip->ip_dst.s_addr);
 
@@ -876,9 +912,8 @@ ip_forward(ip, ifp)
 			dest = ip->ip_dst;
 		    /*
 		     * If the destination is reached by a route to host,
-		     * is directly on the attached net (!),
-		     * or if the destination is on a subnet of a local net
-		     * not known to the source net, use host redirect.
+		     * 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;
@@ -888,8 +923,8 @@ ip_forward(ip, ifp)
 			code = ICMP_REDIRECT_HOST;
 		    else for (ia = in_ifaddr; ia = ia->ia_next; )
 			if ((dst & ia->ia_netmask) == ia->ia_net) {
-			    if ((src & ia->ia_netmask) != ia->ia_net)
-				code = ICMP_REDIRECT_HOST;
+			    if (ia->ia_subnetmask != ia->ia_netmask)
+				    code = ICMP_REDIRECT_HOST;
 			    break;
 			}
 		    if (ipprintfs)
@@ -922,7 +957,10 @@ ip_forward(ip, ifp)
 
 	case ENETUNREACH:
 	case ENETDOWN:
-		code = ICMP_UNREACH_NET;
+		if (in_localaddr(ip->ip_dst))
+			code = ICMP_UNREACH_HOST;
+		else
+			code = ICMP_UNREACH_NET;
 		break;
 
 	case EMSGSIZE: