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Diffstat (limited to 'slirp/src/ip_input.c')
-rw-r--r--slirp/src/ip_input.c471
1 files changed, 471 insertions, 0 deletions
diff --git a/slirp/src/ip_input.c b/slirp/src/ip_input.c
new file mode 100644
index 0000000000..e0b94b0e42
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+++ b/slirp/src/ip_input.c
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+/*
+ * 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 "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);
+}
+
+void ip_cleanup(Slirp *slirp)
+{
+ udp_cleanup(slirp);
+ tcp_cleanup(slirp);
+ icmp_cleanup(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;
+
+ if (!slirp->in_enabled) {
+ goto bad;
+ }
+
+ DEBUG_CALL("ip_input");
+ DEBUG_ARG("m = %p", m);
+ DEBUG_ARG("m_len = %d", m->m_len);
+
+ if (m->m_len < sizeof (struct ip)) {
+ goto bad;
+ }
+
+ 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_send_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, AF_INET);
+ 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);
+}
+
+#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 = %p", ip);
+ DEBUG_ARG("fp = %p", fp);
+ DEBUG_ARG("m = %p", 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 = %p", 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);
+ }
+ }
+}
+
+/*
+ * 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 char *opts;
+ int olen;
+
+ olen = (ip->ip_hl<<2) - sizeof (struct ip);
+ opts = (char *)(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;
+}
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