Archipelago » qemu

/*

 * 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. 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

 * ip_input.c,v 1.11 1994/11/16 10:17:08 jkh Exp

 */

/*

 * Changes and additions relating to SLiRP are

 * Copyright (c) 1995 Danny Gasparovski.

 *

 * Please read the file COPYRIGHT for the

 * terms and conditions of the copyright.

 */

#include <slirp.h>

#include <osdep.h>

#include "ip_icmp.h"

static struct ip *ip_reass(Slirp *slirp, struct ip *ip, struct ipq *fp);

static void ip_freef(Slirp *slirp, struct ipq *fp);

static void ip_enq(register struct ipasfrag *p,

                   register struct ipasfrag *prev);

static void ip_deq(register struct ipasfrag *p);

/*

 * IP initialization: fill in IP protocol switch table.

 * All protocols not implemented in kernel go to raw IP protocol handler.

 */

void

ip_init(Slirp *slirp)

{

    slirp->ipq.ip_link.next = slirp->ipq.ip_link.prev = &slirp->ipq.ip_link;

    udp_init(slirp);

    tcp_init(slirp);

    icmp_init(slirp);

}

/*

 * Ip input routine.  Checksum and byte swap header.  If fragmented

 * try to reassemble.  Process options.  Pass to next level.

 */

void

ip_input(struct mbuf *m)

{

        Slirp *slirp = m->slirp;

        register struct ip *ip;

        int hlen;

        DEBUG_CALL("ip_input");

        DEBUG_ARG("m = %lx", (long)m);

        DEBUG_ARG("m_len = %d", m->m_len);

        if (m->m_len < sizeof (struct ip)) {

                return;

        }

        ip = mtod(m, struct ip *);

        if (ip->ip_v != IPVERSION) {

                goto bad;

        }

        hlen = ip->ip_hl << 2;

        if (hlen<sizeof(struct ip ) || hlen>m->m_len) {/* min header length */

          goto bad;                                  /* or packet too short */

        }

        /* keep ip header intact for ICMP reply

         * ip->ip_sum = cksum(m, hlen);

         * if (ip->ip_sum) {

         */

        if(cksum(m,hlen)) {

          goto bad;

        }

        /*

         * Convert fields to host representation.

         */

        NTOHS(ip->ip_len);

        if (ip->ip_len < hlen) {

                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_len < ip->ip_len) {

                goto bad;

        }

        /* Should drop packet if mbuf too long? hmmm... */

        if (m->m_len > ip->ip_len)

           m_adj(m, ip->ip_len - m->m_len);

        /* check ip_ttl for a correct ICMP reply */

        if(ip->ip_ttl==0) {

          icmp_error(m, ICMP_TIMXCEED,ICMP_TIMXCEED_INTRANS, 0,"ttl");

          goto bad;

        }

        /*

         * 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.)

         *

         * XXX This should fail, don't fragment yet

         */

        if (ip->ip_off &~ IP_DF) {

          register struct ipq *fp;

      struct qlink *l;

                /*

                 * Look for queue of fragments

                 * of this datagram.

                 */

                for (l = slirp->ipq.ip_link.next; l != &slirp->ipq.ip_link;

                     l = l->next) {

            fp = container_of(l, struct ipq, ip_link);

            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 = NULL;

        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;

                if (ip->ip_off & IP_MF)

                  ip->ip_tos |= 1;

                else

                  ip->ip_tos &= ~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 (ip->ip_tos & 1 || ip->ip_off) {

                        ip = ip_reass(slirp, ip, fp);

                        if (ip == NULL)

                                return;

                        m = dtom(slirp, ip);

                } else

                        if (fp)

                              ip_freef(slirp, fp);

        } else

                ip->ip_len -= hlen;

        /*

         * Switch out to protocol's input routine.

         */

        switch (ip->ip_p) {

         case IPPROTO_TCP:

                tcp_input(m, hlen, (struct socket *)NULL);

                break;

         case IPPROTO_UDP:

                udp_input(m, hlen);

                break;

         case IPPROTO_ICMP:

                icmp_input(m, hlen);

                break;

         default:

                m_free(m);

        }

        return;

bad:

        m_free(m);

        return;

}

#define iptofrag(P) ((struct ipasfrag *)(((char*)(P)) - sizeof(struct qlink)))

#define fragtoip(P) ((struct ip*)(((char*)(P)) + sizeof(struct qlink)))

/*

 * Take incoming datagram fragment and try to

 * reassemble it into whole datagram.  If a chain for

 * reassembly of this datagram already exists, then it

 * is given as fp; otherwise have to make a chain.

 */

static struct ip *

ip_reass(Slirp *slirp, struct ip *ip, struct ipq *fp)

{

        register struct mbuf *m = dtom(slirp, ip);

        register struct ipasfrag *q;

        int hlen = ip->ip_hl << 2;

        int i, next;

        DEBUG_CALL("ip_reass");

        DEBUG_ARG("ip = %lx", (long)ip);

        DEBUG_ARG("fp = %lx", (long)fp);

        DEBUG_ARG("m = %lx", (long)m);

        /*

         * Presence of header sizes in mbufs

         * would confuse code below.

         * Fragment m_data is concatenated.

         */

        m->m_data += hlen;

        m->m_len -= hlen;

        /*

         * If first fragment to arrive, create a reassembly queue.

         */

        if (fp == NULL) {

          struct mbuf *t = m_get(slirp);

          if (t == NULL) {

              goto dropfrag;

          }

          fp = mtod(t, struct ipq *);

          insque(&fp->ip_link, &slirp->ipq.ip_link);

          fp->ipq_ttl = IPFRAGTTL;

          fp->ipq_p = ip->ip_p;

          fp->ipq_id = ip->ip_id;

          fp->frag_link.next = fp->frag_link.prev = &fp->frag_link;

          fp->ipq_src = ip->ip_src;

          fp->ipq_dst = ip->ip_dst;

          q = (struct ipasfrag *)fp;

          goto insert;

        }

        /*

         * Find a segment which begins after this one does.

         */

        for (q = fp->frag_link.next; q != (struct ipasfrag *)&fp->frag_link;

            q = q->ipf_next)

                if (q->ipf_off > ip->ip_off)

                        break;

        /*

         * If there is a preceding segment, it may provide some of

         * our data already.  If so, drop the data from the incoming

         * segment.  If it provides all of our data, drop us.

         */

        if (q->ipf_prev != &fp->frag_link) {

        struct ipasfrag *pq = q->ipf_prev;

                i = pq->ipf_off + pq->ipf_len - ip->ip_off;

                if (i > 0) {

                        if (i >= ip->ip_len)

                                goto dropfrag;

                        m_adj(dtom(slirp, ip), i);

                        ip->ip_off += i;

                        ip->ip_len -= i;

                }

        }

        /*

         * While we overlap succeeding segments trim them or,

         * if they are completely covered, dequeue them.

         */

        while (q != (struct ipasfrag*)&fp->frag_link &&

            ip->ip_off + ip->ip_len > q->ipf_off) {

                i = (ip->ip_off + ip->ip_len) - q->ipf_off;

                if (i < q->ipf_len) {

                        q->ipf_len -= i;

                        q->ipf_off += i;

                        m_adj(dtom(slirp, q), i);

                        break;

                }

                q = q->ipf_next;

                m_free(dtom(slirp, q->ipf_prev));

                ip_deq(q->ipf_prev);

        }

insert:

        /*

         * Stick new segment in its place;

         * check for complete reassembly.

         */

        ip_enq(iptofrag(ip), q->ipf_prev);

        next = 0;

        for (q = fp->frag_link.next; q != (struct ipasfrag*)&fp->frag_link;

            q = q->ipf_next) {

                if (q->ipf_off != next)

                        return NULL;

                next += q->ipf_len;

        }

        if (((struct ipasfrag *)(q->ipf_prev))->ipf_tos & 1)

                return NULL;

        /*

         * Reassembly is complete; concatenate fragments.

         */

    q = fp->frag_link.next;

        m = dtom(slirp, q);

        q = (struct ipasfrag *) q->ipf_next;

        while (q != (struct ipasfrag*)&fp->frag_link) {

          struct mbuf *t = dtom(slirp, q);

          q = (struct ipasfrag *) q->ipf_next;

          m_cat(m, t);

        }

        /*

         * Create header for new ip packet by

         * modifying header of first packet;

         * dequeue and discard fragment reassembly header.

         * Make header visible.

         */

        q = fp->frag_link.next;

        /*

         * If the fragments concatenated to an mbuf that's

         * bigger than the total size of the fragment, then and

         * m_ext buffer was alloced. But fp->ipq_next points to

         * the old buffer (in the mbuf), so we must point ip

         * into the new buffer.

         */

        if (m->m_flags & M_EXT) {

          int delta = (char *)q - m->m_dat;

          q = (struct ipasfrag *)(m->m_ext + delta);

        }

    ip = fragtoip(q);

        ip->ip_len = next;

        ip->ip_tos &= ~1;

        ip->ip_src = fp->ipq_src;

        ip->ip_dst = fp->ipq_dst;

        remque(&fp->ip_link);

        (void) m_free(dtom(slirp, fp));

        m->m_len += (ip->ip_hl << 2);

        m->m_data -= (ip->ip_hl << 2);

        return ip;

dropfrag:

        m_free(m);

        return NULL;

}

/*

 * Free a fragment reassembly header and all

 * associated datagrams.

 */

static void

ip_freef(Slirp *slirp, struct ipq *fp)

{

        register struct ipasfrag *q, *p;

        for (q = fp->frag_link.next; q != (struct ipasfrag*)&fp->frag_link; q = p) {

                p = q->ipf_next;

                ip_deq(q);

                m_free(dtom(slirp, q));

        }

        remque(&fp->ip_link);

        (void) m_free(dtom(slirp, fp));

}

/*

 * Put an ip fragment on a reassembly chain.

 * Like insque, but pointers in middle of structure.

 */

static void

ip_enq(register struct ipasfrag *p, register struct ipasfrag *prev)

{

        DEBUG_CALL("ip_enq");

        DEBUG_ARG("prev = %lx", (long)prev);

        p->ipf_prev =  prev;

        p->ipf_next = prev->ipf_next;

        ((struct ipasfrag *)(prev->ipf_next))->ipf_prev = p;

        prev->ipf_next = p;

}

/*

 * To ip_enq as remque is to insque.

 */

static void

ip_deq(register struct ipasfrag *p)

{

        ((struct ipasfrag *)(p->ipf_prev))->ipf_next = p->ipf_next;

        ((struct ipasfrag *)(p->ipf_next))->ipf_prev = p->ipf_prev;

}

/*

 * IP timer processing;

 * if a timer expires on a reassembly

 * queue, discard it.

 */

void

ip_slowtimo(Slirp *slirp)

{

    struct qlink *l;

        DEBUG_CALL("ip_slowtimo");

    l = slirp->ipq.ip_link.next;

        if (l == NULL)

           return;

    while (l != &slirp->ipq.ip_link) {

        struct ipq *fp = container_of(l, struct ipq, ip_link);

        l = l->next;

                if (--fp->ipq_ttl == 0) {

                        ip_freef(slirp, fp);

                }

    }

}

/*

 * Do option processing on a datagram,

 * possibly discarding it if bad options are encountered,

 * or forwarding it if source-routed.

 * Returns 1 if packet has been forwarded/freed,

 * 0 if the packet should be processed further.

 */

#ifdef notdef

int

ip_dooptions(m)

        struct mbuf *m;

{

        register struct ip *ip = mtod(m, struct ip *);

        register u_char *cp;

        register struct ip_timestamp *ipt;

        register struct in_ifaddr *ia;

        int opt, optlen, cnt, off, code, type, forward = 0;

        struct in_addr *sin, dst;

typedef uint32_t n_time;

        n_time ntime;

        dst = ip->ip_dst;

        cp = (u_char *)(ip + 1);

        cnt = (ip->ip_hl << 2) - sizeof (struct ip);

        for (; cnt > 0; cnt -= optlen, cp += optlen) {

                opt = cp[IPOPT_OPTVAL];

                if (opt == IPOPT_EOL)

                        break;

                if (opt == IPOPT_NOP)

                        optlen = 1;

                else {

                        optlen = cp[IPOPT_OLEN];

                        if (optlen <= 0 || optlen > cnt) {

                                code = &cp[IPOPT_OLEN] - (u_char *)ip;

                                goto bad;

                        }

                }

                switch (opt) {

                default:

                        break;

                /*

                 * Source routing with record.

                 * Find interface with current destination address.

                 * If none on this machine then drop if strictly routed,

                 * or do nothing if loosely routed.

                 * Record interface address and bring up next address

                 * component.  If strictly routed make sure next

                 * address is on directly accessible net.

                 */

                case IPOPT_LSRR:

                case IPOPT_SSRR:

                        if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) {

                                code = &cp[IPOPT_OFFSET] - (u_char *)ip;

                                goto bad;

                        }

                        ipaddr.sin_addr = ip->ip_dst;

                        ia = (struct in_ifaddr *)

                                ifa_ifwithaddr((struct sockaddr *)&ipaddr);

                        if (ia == 0) {

                                if (opt == IPOPT_SSRR) {

                                        type = ICMP_UNREACH;

                                        code = ICMP_UNREACH_SRCFAIL;

                                        goto bad;

                                }

                                /*

                                 * Loose routing, and not at next destination

                                 * yet; nothing to do except forward.

                                 */

                                break;

                        }

                        off--; /* 0 origin */

                        if (off > optlen - sizeof(struct in_addr)) {

                                /*

                                 * End of source route.  Should be for us.

                                 */

                                save_rte(cp, ip->ip_src);

                                break;

                        }

                        /*

                         * locate outgoing interface

                         */

                        bcopy((caddr_t)(cp + off), (caddr_t)&ipaddr.sin_addr,

                            sizeof(ipaddr.sin_addr));

                        if (opt == IPOPT_SSRR) {

#define        INA        struct in_ifaddr *

#define        SA        struct sockaddr *

                             if ((ia = (INA)ifa_ifwithdstaddr((SA)&ipaddr)) == 0)

                                ia = (INA)ifa_ifwithnet((SA)&ipaddr);

                        } else

                                ia = ip_rtaddr(ipaddr.sin_addr);

                        if (ia == 0) {

                                type = ICMP_UNREACH;

                                code = ICMP_UNREACH_SRCFAIL;

                                goto bad;

                        }

                        ip->ip_dst = ipaddr.sin_addr;

                        bcopy((caddr_t)&(IA_SIN(ia)->sin_addr),

                            (caddr_t)(cp + off), sizeof(struct in_addr));

                        cp[IPOPT_OFFSET] += sizeof(struct in_addr);

                        /*

                         * Let ip_intr's mcast routing check handle mcast pkts

                         */

                        forward = !IN_MULTICAST(ntohl(ip->ip_dst.s_addr));

                        break;

                case IPOPT_RR:

                        if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) {

                                code = &cp[IPOPT_OFFSET] - (u_char *)ip;

                                goto bad;

                        }

                        /*

                         * If no space remains, ignore.

                         */

                        off--; /* 0 origin */

                        if (off > optlen - sizeof(struct in_addr))

                                break;

                        bcopy((caddr_t)(&ip->ip_dst), (caddr_t)&ipaddr.sin_addr,

                            sizeof(ipaddr.sin_addr));

                        /*

                         * locate outgoing interface; if we're the destination,

                         * use the incoming interface (should be same).

                         */

                        if ((ia = (INA)ifa_ifwithaddr((SA)&ipaddr)) == 0 &&

                            (ia = ip_rtaddr(ipaddr.sin_addr)) == 0) {

                                type = ICMP_UNREACH;

                                code = ICMP_UNREACH_HOST;

                                goto bad;

                        }

                        bcopy((caddr_t)&(IA_SIN(ia)->sin_addr),

                            (caddr_t)(cp + off), sizeof(struct in_addr));

                        cp[IPOPT_OFFSET] += sizeof(struct in_addr);

                        break;

                case IPOPT_TS:

                        code = cp - (u_char *)ip;

                        ipt = (struct ip_timestamp *)cp;

                        if (ipt->ipt_len < 5)

                                goto bad;

                        if (ipt->ipt_ptr > ipt->ipt_len - sizeof (int32_t)) {

                                if (++ipt->ipt_oflw == 0)

                                        goto bad;

                                break;

                        }

                        sin = (struct in_addr *)(cp + ipt->ipt_ptr - 1);

                        switch (ipt->ipt_flg) {

                        case IPOPT_TS_TSONLY:

                                break;

                        case IPOPT_TS_TSANDADDR:

                                if (ipt->ipt_ptr + sizeof(n_time) +

                                    sizeof(struct in_addr) > ipt->ipt_len)

                                        goto bad;

                                ipaddr.sin_addr = dst;

                                ia = (INA)ifaof_ i f p foraddr((SA)&ipaddr,

                                                            m->m_pkthdr.rcvif);

                                if (ia == 0)

                                        continue;

                                bcopy((caddr_t)&IA_SIN(ia)->sin_addr,

                                    (caddr_t)sin, sizeof(struct in_addr));

                                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((SA)&ipaddr) == 0)

                                        continue;

                                ipt->ipt_ptr += sizeof(struct in_addr);

                                break;

                        default:

                                goto bad;

                        }

                        ntime = iptime();

                        bcopy((caddr_t)&ntime, (caddr_t)cp + ipt->ipt_ptr - 1,

                            sizeof(n_time));

                        ipt->ipt_ptr += sizeof(n_time);

                }

        }

        if (forward) {

                ip_forward(m, 1);

                return (1);

        }

        return (0);

bad:

         icmp_error(m, type, code, 0, 0);

        return (1);

}

#endif /* notdef */

/*

 * Strip out IP options, at higher

 * level protocol in the kernel.

 * Second argument is buffer to which options

 * will be moved, and return value is their length.

 * (XXX) should be deleted; last arg currently ignored.

 */

void

ip_stripoptions(register struct mbuf *m, struct mbuf *mopt)

{

        register int i;

        struct ip *ip = mtod(m, struct ip *);

        register caddr_t opts;

        int olen;

        olen = (ip->ip_hl<<2) - sizeof (struct ip);

        opts = (caddr_t)(ip + 1);

        i = m->m_len - (sizeof (struct ip) + olen);

        memcpy(opts, opts  + olen, (unsigned)i);

        m->m_len -= olen;

        ip->ip_hl = sizeof(struct ip) >> 2;

}