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/* $OpenBSD: ip_ah.c,v 1.13 1997/11/04 09:10:58 provos Exp $ */
/*
* The author of this code is John Ioannidis, ji@tla.org,
* (except when noted otherwise).
*
* This code was written for BSD/OS in Athens, Greece, in November 1995.
*
* Ported to OpenBSD and NetBSD, with additional transforms, in December 1996,
* by Angelos D. Keromytis, kermit@forthnet.gr.
*
* Additional transforms and features in 1997 by Angelos D. Keromytis and
* Niels Provos.
*
* Copyright (C) 1995, 1996, 1997 by John Ioannidis, Angelos D. Keromytis
* and Niels Provos.
*
* Permission to use, copy, and modify this software without fee
* is hereby granted, provided that this entire notice is included in
* all copies of any software which is or includes a copy or
* modification of this software.
*
* THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR
* IMPLIED WARRANTY. IN PARTICULAR, NEITHER AUTHOR MAKES ANY
* REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE
* MERCHANTABILITY OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR
* PURPOSE.
*/
/*
* Authentication Header Processing
* Per RFC1826 (Atkinson, 1995)
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/domain.h>
#include <sys/protosw.h>
#include <sys/socket.h>
#include <sys/errno.h>
#include <sys/time.h>
#include <sys/kernel.h>
#include <machine/cpu.h>
#include <net/if.h>
#include <net/route.h>
#include <net/netisr.h>
#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#include <netinet/in_pcb.h>
#include <netinet/in_var.h>
#include <netinet/ip_var.h>
#include <netinet/ip_icmp.h>
#include <sys/socketvar.h>
#include <net/raw_cb.h>
#include <net/encap.h>
#include <netinet/ip_ipsp.h>
#include <netinet/ip_ah.h>
#include <sys/syslog.h>
void ah_input __P((struct mbuf *, int));
/*
* ah_input gets called when we receive an packet with an AH.
*/
void
ah_input(register struct mbuf *m, int iphlen)
{
struct ifqueue *ifq = NULL;
struct ah_old *ahp, ahn;
struct expiration *exp;
struct ip *ipo, ipn;
struct tdb *tdbp;
int s;
ahstat.ahs_input++;
/*
* Make sure that at least the fixed part of the AH header is
* in the first mbuf.
*/
ipo = mtod(m, struct ip *);
if (m->m_len < iphlen + AH_OLD_FLENGTH)
{
if ((m = m_pullup(m, iphlen + AH_OLD_FLENGTH)) == 0)
{
#ifdef ENCDEBUG
if (encdebug)
printf("ah_input(): (possibly too short) packet from %x to %x dropped\n", ipo->ip_src, ipo->ip_dst);
#endif /* ENCDEBUG */
ahstat.ahs_hdrops++;
return;
}
ipo = mtod(m, struct ip *);
}
ahp = (struct ah_old *) ((caddr_t) ipo + iphlen);
/*
* Find tunnel control block and (indirectly) call the appropriate
* tranform routine. The resulting mbuf chain is a valid
* IP packet ready to go through input processing.
*/
tdbp = gettdb(ahp->ah_spi, ipo->ip_dst, IPPROTO_AH);
if (tdbp == NULL)
{
if (encdebug)
log(LOG_ERR, "ah_input(): could not find SA for AH packet from %x to %x, spi %08x\n", ipo->ip_src, ipo->ip_dst, ntohl(ahp->ah_spi));
m_freem(m);
ahstat.ahs_notdb++;
return;
}
if (tdbp->tdb_flags & TDBF_INVALID)
{
if (encdebug)
log(LOG_ALERT, "ah_input(): attempted to use invalid AH SA %08x, packet %x->%x\n", ntohl(ahp->ah_spi), ipo->ip_src, ipo->ip_dst);
m_freem(m);
ahstat.ahs_invalid++;
return;
}
if (tdbp->tdb_xform == NULL)
{
if (encdebug)
log(LOG_ALERT, "ah_input(): attempted to use uninitialized AH SA %08x, packet from %x to %x\n", ntohl(ahp->ah_spi), ipo->ip_src, ipo->ip_dst);
m_freem(m);
ahstat.ahs_noxform++;
return;
}
m->m_pkthdr.rcvif = &enc_softc;
/* Register first use, setup expiration timer */
if (tdbp->tdb_first_use == 0)
{
tdbp->tdb_first_use = time.tv_sec;
if (tdbp->tdb_flags & TDBF_FIRSTUSE)
{
exp = get_expiration();
if (exp == (struct expiration *) NULL)
{
if (encdebug)
log(LOG_WARNING,
"ah_input(): out of memory for expiration timer\n");
ahstat.ahs_hdrops++;
m_freem(m);
return;
}
exp->exp_dst.s_addr = tdbp->tdb_dst.s_addr;
exp->exp_spi = tdbp->tdb_spi;
exp->exp_sproto = tdbp->tdb_sproto;
exp->exp_timeout = tdbp->tdb_first_use + tdbp->tdb_exp_first_use;
put_expiration(exp);
}
if ((tdbp->tdb_flags & TDBF_SOFT_FIRSTUSE) &&
(tdbp->tdb_soft_first_use <= tdbp->tdb_exp_first_use))
{
exp = get_expiration();
if (exp == (struct expiration *) NULL)
{
if (encdebug)
log(LOG_WARNING,
"ah_input(): out of memory for expiration timer\n");
ahstat.ahs_hdrops++;
m_freem(m);
return;
}
exp->exp_dst.s_addr = tdbp->tdb_dst.s_addr;
exp->exp_spi = tdbp->tdb_spi;
exp->exp_sproto = tdbp->tdb_sproto;
exp->exp_timeout = tdbp->tdb_first_use + tdbp->tdb_soft_first_use;
put_expiration(exp);
}
}
ipn = *ipo;
ahn = *ahp;
m = (*(tdbp->tdb_xform->xf_input))(m, tdbp);
if (m == NULL)
{
if (encdebug)
log(LOG_ALERT, "ah_input(): authentication failed for AH packet from %x to %x, spi %08x\n", ipn.ip_src, ipn.ip_dst, ntohl(ahn.ah_spi));
ahstat.ahs_badkcr++;
return;
}
ipo = mtod(m, struct ip *);
if (ipo->ip_p == IPPROTO_IPIP) /* IP-in-IP encapsulation */
{
/* Encapsulating SPI */
if (tdbp->tdb_osrc.s_addr && tdbp->tdb_odst.s_addr)
{
if (tdbp->tdb_flags & TDBF_UNIQUE)
if ((ipn.ip_src.s_addr != ipo->ip_src.s_addr) ||
(ipn.ip_dst.s_addr != ipo->ip_dst.s_addr))
{
if (encdebug)
log(LOG_ALERT, "ah_input(): AH-tunnel with different internal addresses %x/%x, SA %08x/%x\n", ipo->ip_src, ipo->ip_dst, tdbp->tdb_spi, tdbp->tdb_dst);
m_freem(m);
ahstat.ahs_hdrops++;
return;
}
}
else /* So we're paranoid */
{
if (encdebug)
log(LOG_ALERT, "ah_input(): AH-tunnel used when expecting AH-transport, SA %08x/%x\n", tdbp->tdb_spi, tdbp->tdb_dst);
m_freem(m);
ahstat.ahs_hdrops++;
return;
}
}
/*
* Interface pointer is already in first mbuf; chop off the
* `outer' header and reschedule.
*/
ifq = &ipintrq;
s = splimp(); /* isn't it already? */
if (IF_QFULL(ifq))
{
IF_DROP(ifq);
m_freem(m);
ahstat.ahs_qfull++;
splx(s);
#ifdef ENCDEBUG
if (encdebug)
printf("ah_input(): dropped packet because of full IP queue\n");
#endif /* ENCDEBUG */
return;
}
IF_ENQUEUE(ifq, m);
schednetisr(NETISR_IP);
splx(s);
return;
}
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