ip_input.c

MIPS处理器的bootloader,龙芯就是用的修改过的PMON2

/*	$OpenBSD: ip_input.c,v 1.42 1999/09/25 06:35:48 deraadt Exp $	*/
/*	$NetBSD: ip_input.c,v 1.30 1996/03/16 23:53:58 christos Exp $	*/

/*
 * Copyright (c) 1982, 1986, 1988, 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *	@(#)ip_input.c	8.2 (Berkeley) 1/4/94
 */

#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 <sys/syslog.h>
#include <sys/proc.h>

#include <vm/vm.h>
#include <sys/sysctl.h>

#include <net/if.h>
#include <net/if_dl.h>
#include <net/route.h>

#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/if_ether.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 <netinet/ip_ipsp.h>

#ifndef	IPFORWARDING
#ifdef GATEWAY
#define	IPFORWARDING	1	/* forward IP packets not for us */
#else /* GATEWAY */
#define	IPFORWARDING	0	/* don't forward IP packets not for us */
#endif /* GATEWAY */
#endif /* IPFORWARDING */
#ifndef	IPSENDREDIRECTS
#define	IPSENDREDIRECTS	1
#endif

int encdebug = 0;

/*
 * Note: DIRECTED_BROADCAST is handled this way so that previous
 * configuration using this option will Just Work.
 */
#ifndef IPDIRECTEDBCAST
#ifdef DIRECTED_BROADCAST
#define IPDIRECTEDBCAST	1
#else
#define	IPDIRECTEDBCAST	0
#endif /* DIRECTED_BROADCAST */
#endif /* IPDIRECTEDBCAST */
int	ipforwarding = IPFORWARDING;
int	ipsendredirects = IPSENDREDIRECTS;
int	ip_dosourceroute = 0;	/* no src-routing unless sysctl'd to enable */
int	ip_defttl = IPDEFTTL;
int	ip_directedbcast = IPDIRECTEDBCAST;
#ifdef DIAGNOSTIC
int	ipprintfs = 0;
#endif

int	ipsec_auth_default_level = IPSEC_AUTH_LEVEL_DEFAULT;
int	ipsec_esp_trans_default_level = IPSEC_ESP_TRANS_LEVEL_DEFAULT;
int	ipsec_esp_network_default_level = IPSEC_ESP_NETWORK_LEVEL_DEFAULT;

/* Keep track of memory used for reassembly */
int	ip_maxqueue = 300;
int	ip_frags = 0;

/* from in_pcb.c */
extern int ipport_firstauto;
extern int ipport_lastauto;
extern int ipport_hifirstauto;
extern int ipport_hilastauto;
extern struct baddynamicports baddynamicports;

extern	struct domain inetdomain;
extern	struct protosw inetsw[];
u_char	ip_protox[IPPROTO_MAX];
int	ipqmaxlen = IFQ_MAXLEN;
struct	in_ifaddrhead in_ifaddr;
struct	ifqueue ipintrq;
#if defined(IPFILTER) || defined(IPFILTER_LKM)
int	(*fr_checkp) __P((struct ip *, int, struct ifnet *, int,
			  struct mbuf **));
#endif

int	ipq_locked;
static __inline int ipq_lock_try __P((void));
static __inline void ipq_unlock __P((void));

static __inline int
ipq_lock_try()
{
	int s;

	s = splimp();
	if (ipq_locked) {
		splx(s);
		return (0);
	}
	ipq_locked = 1;
	splx(s);
	return (1);
}

#define ipq_lock() ipq_lock_try()

static __inline void
ipq_unlock()
{
	int s;

	s = splimp();
	ipq_locked = 0;
	splx(s);
}

char *
inet_ntoa(ina)
	struct in_addr ina;
{
	static char buf[4*sizeof "123"];
	unsigned char *ucp = (unsigned char *)&ina;

	sprintf(buf, "%d.%d.%d.%d", ucp[0] & 0xff, ucp[1] & 0xff,
	    ucp[2] & 0xff, ucp[3] & 0xff);
	return (buf);
}

/*
 * 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 {
	struct	in_addr dst;			/* final destination */
	char	nop;				/* one NOP to align */
	char	srcopt[IPOPT_OFFSET + 1];	/* OPTVAL, OLEN and OFFSET */
	struct	in_addr route[MAX_IPOPTLEN/sizeof(struct in_addr)];
} ip_srcrt;

static void save_rte __P((u_char *, struct in_addr));
#ifndef PMON
static int ip_weadvertise(u_int32_t);
#endif

/*
 * IP initialization: fill in IP protocol switch table.
 * All protocols not implemented in kernel go to raw IP protocol handler.
 */
void
ip_init()
{
	register struct protosw *pr;
	register int i;
	const u_int16_t defbaddynamicports_tcp[] = DEFBADDYNAMICPORTS_TCP;
	const u_int16_t defbaddynamicports_udp[] = DEFBADDYNAMICPORTS_UDP;

	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_domain->dom_family == PF_INET &&
		    pr->pr_protocol && pr->pr_protocol != IPPROTO_RAW)
			ip_protox[pr->pr_protocol] = pr - inetsw;
	LIST_INIT(&ipq);
	ipintrq.ifq_maxlen = ipqmaxlen;
	TAILQ_INIT(&in_ifaddr);

	/* Fill in list of ports not to allocate dynamically. */
	bzero((void *)&baddynamicports, sizeof(baddynamicports));
	for (i = 0; defbaddynamicports_tcp[i] != 0; i++)
		DP_SET(baddynamicports.tcp, defbaddynamicports_tcp[i]);
	for (i = 0; defbaddynamicports_udp[i] != 0; i++)
		DP_SET(baddynamicports.udp, defbaddynamicports_tcp[i]);
}

struct	sockaddr_in ipaddr = { sizeof(ipaddr), AF_INET };
struct	route ipforward_rt;

void
ipintr()
{
	register struct mbuf *m;
	int s;

	if (needqueuedrain)
		m_reclaim();
	
	while (1) {
		/*
		 * 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
		ipv4_input(m, 0, NULL, 0);
	}
}

/*
 * Ip input routine.  Checksum and byte swap header.  If fragmented
 * try to reassemble.  Process options.  Pass to next level.
 */
void
ipv4_input(struct mbuf *m, ...)
{
	register struct ip *ip;
	register struct ipq *fp;
	struct in_ifaddr *ia;
	struct ipqent *ipqe;
	int hlen, mff;
#ifndef PMON	/* Never used in pmon */
	va_list ap;
	int extra;

	va_start(ap, m);
	extra = va_arg(ap, int);
	va_end(ap);

	if (extra) {
		struct mbuf *newpacket;

		if (!(newpacket = m_split(m, extra, M_NOWAIT))) {
			m_freem(m);
			return;
		}

		newpacket->m_flags |= m->m_flags;
		m_freem(m);
		m = newpacket;
		extra = 0;
	}
#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.tqh_first == 0)
		goto bad;
	ipstat.ips_total++;
	if (m->m_len < sizeof (struct ip) &&
	    (m = m_pullup(m, sizeof (struct ip))) == 0) {
		ipstat.ips_toosmall++;
		return;
	}
	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++;
			return;
		}
		ip = mtod(m, struct ip *);
	}
	if ((ip->ip_sum = in_cksum(m, hlen)) != 0) {
		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);
	}

#if defined(IPFILTER) || defined(IPFILTER_LKM)
	 /*
	 * Check if we want to allow this packet to be processed.
	 * Consider it to be bad if not.
	 */
	{
		struct mbuf *m0 = m;
		if (fr_checkp && (*fr_checkp)(ip, hlen, m->m_pkthdr.rcvif, 0, &m0))
			return;
		ip = mtod(m = m0, struct ip *);
	}
#endif

	/*
	 * 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))
		return;

	/*
	 * Check our list of addresses, to see if the packet is for us.
	 */
	if ((ia = in_iawithaddr(ip->ip_dst, m)) != NULL &&
	    (ia->ia_ifp->if_flags & IFF_UP))
		goto ours;

	if (IN_MULTICAST(ip->ip_dst.s_addr)) {
		struct in_multi *inm;
#ifdef MROUTING
		extern struct socket *ip_mrouter;

		if (m->m_flags & M_EXT) {
			if ((m = m_pullup(m, hlen)) == 0) {
				ipstat.ips_toosmall++;
				return;
			}
			ip = mtod(m, struct ip *);
		}

		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);
				return;
			}
			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);
			return;
		}
		goto ours;
	}
	if (ip->ip_dst.s_addr == INADDR_BROADCAST ||
	    ip->ip_dst.s_addr == INADDR_ANY)
		goto ours;

	/*
	 * Not for us; forward if possible and desirable.
	 */
#ifndef PMON
	if (ipforwarding == 0) {
#endif
		ipstat.ips_cantforward++;
		m_freem(m);
#ifndef PMON
	} else
		ip_forward(m, 0);
#endif
	return;

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 | IP_RF)) {
		if (m->m_flags & M_EXT) {		/* XXX */
			if ((m = m_pullup(m, hlen)) == 0) {
				ipstat.ips_toosmall++;
				return;
			}
			ip = mtod(m, struct ip *);
		}

		/*
		 * Look for queue of fragments
		 * of this datagram.
		 */
		ipq_lock();
		for (fp = ipq.lh_first; fp != NULL; fp = fp->ipq_q.le_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: