2.11BSD/sys/netinet/ip_icmp.c
/*
* Copyright (c) 1982, 1986 Regents of the University of California.
* All rights reserved.
*
* Redistribution and use in source and binary forms are permitted
* provided that this notice is preserved and that due credit is given
* to the University of California at 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'' without express or implied warranty.
*
* @(#)ip_icmp.c 7.7.2 (2.11BSD GTE) 1995/10/10
*/
#include "param.h"
#include "systm.h"
#include "mbuf.h"
#include "protosw.h"
#include "socket.h"
#include "time.h"
#include "kernel.h"
#include "errno.h"
#include "../net/route.h"
#include "../net/if.h"
#include "domain.h"
#include "in.h"
#include "in_systm.h"
#include "in_var.h"
#include "ip.h"
#include "ip_icmp.h"
#include "icmp_var.h"
extern int icmpmaskrepl;
#ifdef ICMPPRINTFS
/*
* ICMP routines: error generation, receive packet processing, and
* routines to turnaround packets back to the originator, and
* host table maintenance routines.
*/
int icmpprintfs = 0;
#endif
/*
* Generate an error packet of type error
* in response to bad packet ip.
*/
/*VARARGS4*/
icmp_error(oip, type, code, ifp, dest)
struct ip *oip;
int type, code;
struct ifnet *ifp;
struct in_addr dest;
{
register unsigned oiplen = oip->ip_hl << 2;
register struct icmp *icp;
struct mbuf *m;
struct ip *nip;
unsigned icmplen;
#ifdef ICMPPRINTFS
if (icmpprintfs)
printf("icmp_error(%x, %d, %d)\n", oip, type, code);
#endif
if (type != ICMP_REDIRECT)
icmpstat.icps_error++;
/*
* Don't send error if not the first fragment of message.
* Don't error if the old packet protocol was ICMP
* error message, only known informational types.
*/
if (oip->ip_off &~ (IP_MF|IP_DF))
goto free;
if (oip->ip_p == IPPROTO_ICMP && type != ICMP_REDIRECT &&
!ICMP_INFOTYPE(((struct icmp *)((caddr_t)oip + oiplen))->icmp_type)) {
icmpstat.icps_oldicmp++;
goto free;
}
/*
* First, formulate icmp message
*/
m = m_get(M_DONTWAIT, MT_HEADER);
if (m == NULL)
goto free;
icmplen = oiplen + MIN(8, oip->ip_len);
m->m_len = icmplen + ICMP_MINLEN;
m->m_off = MMAXOFF - m->m_len;
icp = mtod(m, struct icmp *);
if ((u_int)type > ICMP_MAXTYPE)
panic("icmp_error");
icmpstat.icps_outhist[type]++;
icp->icmp_type = type;
if (type == ICMP_REDIRECT)
icp->icmp_gwaddr = dest;
else
icp->icmp_void = 0;
if (type == ICMP_PARAMPROB) {
icp->icmp_pptr = code;
code = 0;
}
icp->icmp_code = code;
bcopy((caddr_t)oip, (caddr_t)&icp->icmp_ip, icmplen);
nip = &icp->icmp_ip;
nip->ip_len += oiplen;
nip->ip_len = htons((u_short)nip->ip_len);
/*
* Now, copy old ip header in front of icmp message.
*/
if (m->m_len + oiplen > MLEN)
oiplen = sizeof(struct ip);
if (m->m_len + oiplen > MLEN)
panic("icmp len");
m->m_off -= oiplen;
m->m_len += oiplen;
nip = mtod(m, struct ip *);
bcopy((caddr_t)oip, (caddr_t)nip, oiplen);
nip->ip_len = m->m_len;
nip->ip_p = IPPROTO_ICMP;
icmp_reflect(nip, ifp);
free:
m_freem(dtom(oip));
}
static struct sockproto icmproto = { AF_INET, IPPROTO_ICMP };
static struct sockaddr_in icmpsrc = { AF_INET };
static struct sockaddr_in icmpdst = { AF_INET };
static struct sockaddr_in icmpgw = { AF_INET };
struct in_ifaddr *ifptoia();
/*
* Process a received ICMP message.
*/
icmp_input(m, ifp)
register struct mbuf *m;
struct ifnet *ifp;
{
register struct icmp *icp;
register struct ip *ip = mtod(m, struct ip *);
int icmplen = ip->ip_len, hlen = ip->ip_hl << 2;
register int i;
struct in_ifaddr *ia;
int (*ctlfunc)(), code;
extern u_char ip_protox[];
extern struct in_addr in_makeaddr();
/*
* Locate icmp structure in mbuf, and check
* that not corrupted and of at least minimum length.
*/
#ifdef ICMPPRINTFS
if (icmpprintfs)
printf("icmp_input src %X len %d", ntohl(ip->ip_src), icmplen);
#endif
if (icmplen < ICMP_MINLEN) {
icmpstat.icps_tooshort++;
goto free;
}
i = hlen + MIN(icmplen, ICMP_ADVLENMIN);
if ((m->m_off > MMAXOFF || m->m_len < i) &&
(m = m_pullup(m, i)) == 0) {
icmpstat.icps_tooshort++;
return;
}
ip = mtod(m, struct ip *);
m->m_len -= hlen;
m->m_off += hlen;
icp = mtod(m, struct icmp *);
if (in_cksum(m, icmplen)) {
icmpstat.icps_checksum++;
goto free;
}
m->m_len += hlen;
m->m_off -= hlen;
#ifdef ICMPPRINTFS
/*
* Message type specific processing.
*/
if (icmpprintfs)
printf("icmp_input, type %d code %d\n", icp->icmp_type,
icp->icmp_code);
#endif
if (icp->icmp_type > ICMP_MAXTYPE)
goto raw;
icmpstat.icps_inhist[icp->icmp_type]++;
code = icp->icmp_code;
switch (icp->icmp_type) {
case ICMP_UNREACH:
if (code > 5)
goto badcode;
code += PRC_UNREACH_NET;
goto deliver;
case ICMP_TIMXCEED:
if (code > 1)
goto badcode;
code += PRC_TIMXCEED_INTRANS;
goto deliver;
case ICMP_PARAMPROB:
if (code)
goto badcode;
code = PRC_PARAMPROB;
goto deliver;
case ICMP_SOURCEQUENCH:
if (code)
goto badcode;
code = PRC_QUENCH;
deliver:
/*
* Problem with datagram; advise higher level routines.
*/
icp->icmp_ip.ip_len = ntohs((u_short)icp->icmp_ip.ip_len);
if (icmplen < ICMP_ADVLENMIN || icmplen < ICMP_ADVLEN(icp)) {
icmpstat.icps_badlen++;
goto free;
}
#ifdef ICMPPRINTFS
if (icmpprintfs)
printf("deliver to protocol %d\n", icp->icmp_ip.ip_p);
#endif
icmpsrc.sin_addr = icp->icmp_ip.ip_dst;
if (ctlfunc = inetsw[ip_protox[icp->icmp_ip.ip_p]].pr_ctlinput)
(*ctlfunc)(code, (struct sockaddr *)&icmpsrc,
(caddr_t)&icp->icmp_ip);
break;
badcode:
icmpstat.icps_badcode++;
break;
case ICMP_ECHO:
icp->icmp_type = ICMP_ECHOREPLY;
goto reflect;
case ICMP_TSTAMP:
if (icmplen < ICMP_TSLEN) {
icmpstat.icps_badlen++;
break;
}
icp->icmp_type = ICMP_TSTAMPREPLY;
icp->icmp_rtime = iptime();
icp->icmp_ttime = icp->icmp_rtime; /* bogus, do later! */
goto reflect;
case ICMP_IREQ:
#define satosin(sa) ((struct sockaddr_in *)(sa))
if (in_netof(ip->ip_src) == 0 && (ia = ifptoia(ifp)))
ip->ip_src = in_makeaddr(in_netof(IA_SIN(ia)->sin_addr),
in_lnaof(ip->ip_src));
icp->icmp_type = ICMP_IREQREPLY;
goto reflect;
case ICMP_MASKREQ:
if (icmpmaskrepl == 0)
break;
/*
* We are not able to respond with all ones broadcast
* unless we receive it over a point-to-point interface.
* This check is a 'switch' in 4.4BSD but 2.11's C compiler
* does not allow "long"s in a switch statement.
*/
if (icmplen < ICMP_MASKLEN || (ia = ifptoia(ifp)) == 0)
break;
if ((ip->ip_dst.s_addr == INADDR_BROADCAST ||
ip->ip_dst.s_addr == INADDR_ANY))
icmpdst.sin_addr = ip->ip_src;
else
icmpdst.sin_addr = ip->ip_dst;
icp->icmp_type = ICMP_MASKREPLY;
icp->icmp_mask = htonl(ia->ia_subnetmask);
if (ip->ip_src.s_addr == 0) {
if (ia->ia_ifp->if_flags & IFF_BROADCAST)
ip->ip_src = satosin(&ia->ia_broadaddr)->sin_addr;
else if (ia->ia_ifp->if_flags & IFF_POINTOPOINT)
ip->ip_src = satosin(&ia->ia_dstaddr)->sin_addr;
}
reflect:
ip->ip_len += hlen; /* since ip_input deducts this */
icmpstat.icps_reflect++;
icmpstat.icps_outhist[icp->icmp_type]++;
icmp_reflect(ip, ifp);
return;
case ICMP_REDIRECT:
if (icmplen < ICMP_ADVLENMIN || icmplen < ICMP_ADVLEN(icp)) {
icmpstat.icps_badlen++;
break;
}
/*
* Short circuit routing redirects to force
* immediate change in the kernel's routing
* tables. The message is also handed to anyone
* listening on a raw socket (e.g. the routing
* daemon for use in updating its tables).
*/
icmpgw.sin_addr = ip->ip_src;
icmpdst.sin_addr = icp->icmp_gwaddr;
#ifdef ICMPPRINTFS
if (icmpprintfs)
printf("redirect dst %X to %X\n", ntohl(icp->icmp_ip.ip_dst),
ntohl(icp->icmp_gwaddr));
#endif
if (code == ICMP_REDIRECT_NET || code == ICMP_REDIRECT_TOSNET) {
icmpsrc.sin_addr =
in_makeaddr(in_netof(icp->icmp_ip.ip_dst), INADDR_ANY);
rtredirect((struct sockaddr *)&icmpsrc,
(struct sockaddr *)&icmpdst, RTF_GATEWAY,
(struct sockaddr *)&icmpgw);
icmpsrc.sin_addr = icp->icmp_ip.ip_dst;
pfctlinput(PRC_REDIRECT_NET,
(struct sockaddr *)&icmpsrc);
} else {
icmpsrc.sin_addr = icp->icmp_ip.ip_dst;
rtredirect((struct sockaddr *)&icmpsrc,
(struct sockaddr *)&icmpdst, RTF_GATEWAY | RTF_HOST,
(struct sockaddr *)&icmpgw);
pfctlinput(PRC_REDIRECT_HOST,
(struct sockaddr *)&icmpsrc);
}
break;
/*
* No kernel processing for the following;
* just fall through to send to raw listener.
*/
case ICMP_ECHOREPLY:
case ICMP_TSTAMPREPLY:
case ICMP_IREQREPLY:
case ICMP_MASKREPLY:
default:
break;
}
raw:
icmpsrc.sin_addr = ip->ip_src;
icmpdst.sin_addr = ip->ip_dst;
raw_input(m, &icmproto, (struct sockaddr *)&icmpsrc,
(struct sockaddr *)&icmpdst);
return;
free:
m_freem(m);
}
/*
* Reflect the ip packet back to the source
*/
icmp_reflect(ip, ifp)
register struct ip *ip;
struct ifnet *ifp;
{
register struct in_ifaddr *ia;
struct in_addr t;
struct mbuf *opts = 0, *ip_srcroute();
int optlen = (ip->ip_hl << 2) - sizeof(struct ip);
t = ip->ip_dst;
ip->ip_dst = ip->ip_src;
/*
* If the incoming packet was addressed directly to us,
* use dst as the src for the reply. Otherwise (broadcast
* or anonymous), use the address which corresponds
* to the incoming interface.
*/
for (ia = in_ifaddr; ia; ia = ia->ia_next) {
if (t.s_addr == IA_SIN(ia)->sin_addr.s_addr)
break;
if ((ia->ia_ifp->if_flags & IFF_BROADCAST) &&
t.s_addr == satosin(&ia->ia_broadaddr)->sin_addr.s_addr)
break;
}
if (ia == (struct in_ifaddr *)0)
ia = ifptoia(ifp);
if (ia == (struct in_ifaddr *)0)
ia = in_ifaddr;
t = IA_SIN(ia)->sin_addr;
ip->ip_src = t;
ip->ip_ttl = MAXTTL;
if (optlen > 0) {
/*
* Retrieve any source routing from the incoming packet
* and strip out other options. Adjust the IP length.
*/
opts = ip_srcroute();
ip->ip_len -= optlen;
ip_stripoptions(ip, (struct mbuf *)0);
}
icmp_send(ip, opts);
if (opts)
(void)m_free(opts);
}
struct in_ifaddr *
ifptoia(ifp)
struct ifnet *ifp;
{
register struct in_ifaddr *ia;
for (ia = in_ifaddr; ia; ia = ia->ia_next)
if (ia->ia_ifp == ifp)
return (ia);
return ((struct in_ifaddr *)0);
}
/*
* Send an icmp packet back to the ip level,
* after supplying a checksum.
*/
icmp_send(ip, opts)
register struct ip *ip;
struct mbuf *opts;
{
register int hlen;
register struct icmp *icp;
register struct mbuf *m;
m = dtom(ip);
hlen = ip->ip_hl << 2;
m->m_off += hlen;
m->m_len -= hlen;
icp = mtod(m, struct icmp *);
icp->icmp_cksum = 0;
icp->icmp_cksum = in_cksum(m, ip->ip_len - hlen);
m->m_off -= hlen;
m->m_len += hlen;
#ifdef ICMPPRINTFS
if (icmpprintfs)
printf("icmp_send dst %X src %X\n", ntohl(ip->ip_dst.s_addr), ntohl(ip->ip_src.s_addr));
#endif
(void) ip_output(m, opts, (struct route *)0, 0);
}
n_time
iptime()
{
struct timeval atv;
int s = splhigh();
u_long t;
extern struct timeval time;
extern int lbolt, hz;
cpfromkern(&time, &atv, sizeof(struct timeval));
t = (atv.tv_sec % (24L*60L*60L)) * 1000L
+ (long)mfkd(&lbolt) * 1000L / (long)hz;
splx(s);
return (htonl(t));
}
int
icmp_sysctl(name, namelen, oldp, oldlenp, newp, newlen)
int *name;
u_int namelen;
void *oldp;
size_t *oldlenp;
void *newp;
size_t newlen;
{
/* All sysctl names at this level are terminal. */
if (namelen != 1)
return (ENOTDIR);
switch (name[0]) {
case ICMPCTL_MASKREPL:
return (sysctl_int(oldp, oldlenp, newp, newlen, &icmpmaskrepl));
default:
return (ENOPROTOOPT);
}
/* NOTREACHED */
}