/*
* Ip input routine. Checksum and byte swap header. If fragmented
* try to reassemble. Process options. Pass to next level.
*/
void
ipintr()
{
register struct ip *ip;
register struct mbuf *m;
register struct ipq *fp;
register struct in_ifaddr *ia;
int hlen, s;
next:
/*
* Get next datagram off input queue and get IP header
* in first mbuf.
*/
s = splimp();
IF_DEQUEUE(&ipintrq, m);
splx(s);
if (m == 0)
return;
#ifdef DIAGNOSTIC
if ((m->m_flags & M_PKTHDR) == 0)
panic("ipintr no HDR");
#endif
/*
* 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_len < sizeof (struct ip) &&
(m = m_pullup(m, sizeof (struct ip))) == 0) {
ipstat.ips_toosmall++;
goto next;
}
ip = mtod(m, struct ip *);
if (ip->ip_v != IPVERSION) {
ipstat.ips_badvers++;
goto bad;
}
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;
}
ip = mtod(m, struct ip *);
}
ip->ip_sum = in_cksum(m, hlen);
if (ip->ip_sum) {
ipstat.ips_badsum++;
goto bad;
}
/*
* Convert fields to host representation.
*/
NTOHS(ip->ip_len);
if (ip->ip_len < hlen) {
ipstat.ips_badlen++;
goto bad;
}
NTOHS(ip->ip_id);
NTOHS(ip->ip_off);
/*
* Check that the amount of data in the buffers
* is as at least much as the IP header would have us expect.
* Trim mbufs if longer than we expect.
* Drop packet if shorter than we expect.
*/
if (m->m_pkthdr.len < ip->ip_len) {
ipstat.ips_tooshort++;
goto bad;
}
if (m->m_pkthdr.len > ip->ip_len) {
if (m->m_len == m->m_pkthdr.len) {
m->m_len = ip->ip_len;
m->m_pkthdr.len = ip->ip_len;
} else
m_adj(m, ip->ip_len - m->m_pkthdr.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 and the original packet to be freed).
*/
ip_nhops = 0; /* for source routed packets */
if (hlen > sizeof (struct ip) && ip_dooptions(m))
goto next;
/*
* Check our list of addresses, to see if the packet is for us.
*/
for (ia = in_ifaddr; ia; ia = ia->ia_next) {
#define satosin(sa) ((struct sockaddr_in *)(sa))
if (IA_SIN(ia)->sin_addr.s_addr == ip->ip_dst.s_addr)
goto ours;
if (
#ifdef DIRECTED_BROADCAST
ia->ia_ifp == m->m_pkthdr.rcvif &&
#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;
}
}
if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) {
struct in_multi *inm;
#ifdef MROUTING
extern struct socket *ip_mrouter;
if (ip_mrouter) {
/*
* If we are acting as a multicast router, all
* incoming multicast packets are passed to the
* kernel-level multicast forwarding function.
* The packet is returned (relatively) intact; if
* ip_mforward() returns a non-zero value, the packet
* must be discarded, else it may be accepted below.
*
* (The IP ident field is put in the same byte order
* as expected when ip_mforward() is called from
* ip_output().)
*/
ip->ip_id = htons(ip->ip_id);
if (ip_mforward(m, m->m_pkthdr.rcvif) != 0) {
ipstat.ips_cantforward++;
m_freem(m);
goto next;
}
ip->ip_id = ntohs(ip->ip_id);
/*
* The process-level routing demon needs to receive
* all multicast IGMP packets, whether or not this
* host belongs to their destination groups.
*/
if (ip->ip_p == IPPROTO_IGMP)
goto ours;
ipstat.ips_forward++;
}
#endif
/*
* See if we belong to the destination multicast group on the
* arrival interface.
*/
IN_LOOKUP_MULTI(ip->ip_dst, m->m_pkthdr.rcvif, inm);
if (inm == NULL) {
ipstat.ips_cantforward++;
m_freem(m);
goto next;
}
goto ours;
}
if (ip->ip_dst.s_addr == (u_long)INADDR_BROADCAST)
goto ours;
if (ip->ip_dst.s_addr == INADDR_ANY)
goto ours;
/*
* Not for us; forward if possible and desirable.
*/
if (ipforwarding == 0) {
ipstat.ips_cantforward++;
m_freem(m);
} else
ip_forward(m, 0);
goto next;
ours:
/*
* 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.)
*/
if (ip->ip_off &~ IP_DF) {
if (m->m_flags & M_EXT) { /* XXX */
if ((m = m_pullup(m, sizeof (struct ip))) == 0) {
ipstat.ips_toosmall++;
goto next;
}
ip = mtod(m, struct ip *);
}
/*
* 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 &= ~1;
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 & 1 || ip->ip_off) {
ipstat.ips_fragments++;
ip = ip_reass((struct ipasfrag *)ip, fp);
if (ip == 0)
goto next;
ipstat.ips_reassembled++;
m = dtom(ip);
} else
if (fp)
ip_freef(fp);
} else
/*
* Ip input routine. Checksum and byte swap header. If fragmented
* try to reassamble. If complete and fragment queue exists, discard.
* Process options. Pass to next level.
*/
ipintr()
{
register struct ip *ip;
register struct mbuf *m;
struct mbuf *m0;
register int i;
register struct ipq *fp;
register struct in_ifaddr *ia;
struct ifnet *ifp;
int hlen, s;
/* IOdebug( "ipintr: called" ); */
next:
/*
* Get next datagram off input queue and get IP header
* in first mbuf.
*/
s = splimp();
IF_DEQUEUEIF(&ipintrq, m, ifp);
splx(s);
if (m == NULL)
{
/* IOdebug( "ipintr: no more mbufs" ); */
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 *);
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;
}
ip = mtod(m, struct ip *);
}
if (ipcksum)
if (ip->ip_sum = in_cksum(m, hlen)) {
ipstat.ips_badsum++;
/* IOdebug( "ipintr: bad checksum" ); */
goto bad;
}
/*
* Convert fields to host representation.
*/
ip->ip_len = ntohs((u_short)ip->ip_len);
if (ip->ip_len < hlen) {
ipstat.ips_badlen++;
goto bad;
}
ip->ip_id = ntohs(ip->ip_id);
ip->ip_off = ntohs((u_short)ip->ip_off);
/*
* Check that the amount of data in the buffers
* is as at least much as the IP header would have us expect.
* Trim mbufs if longer than we expect.
* Drop packet if shorter than we expect.
*/
i = -(u_short)ip->ip_len;
m0 = m;
for (;;) {
i += m->m_len;
if (m->m_next == 0)
break;
m = m->m_next;
}
if (i != 0) {
if (i < 0) {
ipstat.ips_tooshort++;
m = m0;
goto bad;
}
if (i <= m->m_len)
m->m_len -= i;
else
m_adj(m0, -i);
}
m = m0;
/*
* 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 and the original packet to be freed).
*/
ip_nhops = 0; /* for source routed packets */
if (hlen > sizeof (struct ip) && ip_dooptions(ip, ifp))
goto next;
/*
* Check our list of addresses, to see if the packet is for us.
*/
/* IOdebug( "ipintr: checking address" ); */
for (ia = in_ifaddr; ia; ia = ia->ia_next) {
#define satosin(sa) ((struct sockaddr_in *)(sa))
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;
}
}
if (ip->ip_dst.s_addr == (u_long)INADDR_BROADCAST)
goto ours;
if (ip->ip_dst.s_addr == INADDR_ANY)
goto ours;
/*
* Not for us; forward if possible and desirable.
*/
ip_forward(ip, ifp);
/* IOdebug( "ipintr: not for us" ); */
goto next;
ours:
/* IOdebug( "ipintr: ours" ); */
/*
* 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.)
*/
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;
/*
* 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)
{
/* IOdebug( "ipintr: attempting reassembly" ); */
ipstat.ips_fragments++;
ip = ip_reass((struct ipasfrag *)ip, fp);
if (ip == NULL)
{
/* IOdebug( "ipintr: attempt failed" ); */
goto next;
}
m = dtom(ip);
}
else
if (fp)
ip_freef(fp);
} else
ip->ip_len -= hlen;
/*
* Switch out to protocol's input routine.
*/
/* IOdebug( "ipintr: handling packet of len %d", ip->ip_len ); */
(*inetsw[ip_protox[ip->ip_p]].pr_input)(m, ifp);
/* IOdebug( "ipintr: handled" ); */
goto next;
bad:
/* IOdebug( "ipintr: bad input" ); */
m_freem(m);
goto next;
}
