root / slirp / ip_output.c @ 4115852b
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/*
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* Copyright (c) 1982, 1986, 1988, 1990, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* @(#)ip_output.c 8.3 (Berkeley) 1/21/94
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* ip_output.c,v 1.9 1994/11/16 10:17:10 jkh Exp
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*/
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/*
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* Changes and additions relating to SLiRP are
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* Copyright (c) 1995 Danny Gasparovski.
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*
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* Please read the file COPYRIGHT for the
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* terms and conditions of the copyright.
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*/
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#include <slirp.h> |
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/* Number of packets queued before we start sending
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* (to prevent allocing too many mbufs) */
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#define IF_THRESH 10 |
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/*
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* IP output. The packet in mbuf chain m contains a skeletal IP
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* header (with len, off, ttl, proto, tos, src, dst).
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* The mbuf chain containing the packet will be freed.
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* The mbuf opt, if present, will not be freed.
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*/
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int
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ip_output(struct socket *so, struct mbuf *m0) |
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{ |
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Slirp *slirp = m0->slirp; |
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register struct ip *ip; |
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register struct mbuf *m = m0; |
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register int hlen = sizeof(struct ip ); |
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int len, off, error = 0; |
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DEBUG_CALL("ip_output");
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DEBUG_ARG("so = %lx", (long)so); |
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DEBUG_ARG("m0 = %lx", (long)m0); |
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ip = mtod(m, struct ip *);
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/*
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* Fill in IP header.
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*/
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ip->ip_v = IPVERSION; |
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ip->ip_off &= IP_DF; |
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ip->ip_id = htons(slirp->ip_id++); |
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ip->ip_hl = hlen >> 2;
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/*
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* If small enough for interface, can just send directly.
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*/
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if ((uint16_t)ip->ip_len <= IF_MTU) {
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ip->ip_len = htons((uint16_t)ip->ip_len); |
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ip->ip_off = htons((uint16_t)ip->ip_off); |
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ip->ip_sum = 0;
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ip->ip_sum = cksum(m, hlen); |
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if_output(so, m); |
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goto done;
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} |
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/*
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* Too large for interface; fragment if possible.
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* Must be able to put at least 8 bytes per fragment.
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*/
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if (ip->ip_off & IP_DF) {
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error = -1;
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goto bad;
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} |
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len = (IF_MTU - hlen) &~ 7; /* ip databytes per packet */ |
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if (len < 8) { |
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error = -1;
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goto bad;
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} |
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{ |
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int mhlen, firstlen = len;
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struct mbuf **mnext = &m->m_nextpkt;
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/*
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* Loop through length of segment after first fragment,
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* make new header and copy data of each part and link onto chain.
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*/
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m0 = m; |
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mhlen = sizeof (struct ip); |
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for (off = hlen + len; off < (uint16_t)ip->ip_len; off += len) {
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register struct ip *mhip; |
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m = m_get(slirp); |
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if (m == NULL) { |
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error = -1;
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goto sendorfree;
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} |
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m->m_data += IF_MAXLINKHDR; |
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mhip = mtod(m, struct ip *);
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*mhip = *ip; |
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m->m_len = mhlen; |
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mhip->ip_off = ((off - hlen) >> 3) + (ip->ip_off & ~IP_MF);
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if (ip->ip_off & IP_MF)
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mhip->ip_off |= IP_MF; |
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if (off + len >= (uint16_t)ip->ip_len)
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len = (uint16_t)ip->ip_len - off; |
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else
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mhip->ip_off |= IP_MF; |
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mhip->ip_len = htons((uint16_t)(len + mhlen)); |
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if (m_copy(m, m0, off, len) < 0) { |
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error = -1;
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goto sendorfree;
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} |
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mhip->ip_off = htons((uint16_t)mhip->ip_off); |
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mhip->ip_sum = 0;
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mhip->ip_sum = cksum(m, mhlen); |
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*mnext = m; |
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mnext = &m->m_nextpkt; |
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} |
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/*
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* Update first fragment by trimming what's been copied out
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* and updating header, then send each fragment (in order).
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*/
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m = m0; |
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m_adj(m, hlen + firstlen - (uint16_t)ip->ip_len); |
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ip->ip_len = htons((uint16_t)m->m_len); |
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ip->ip_off = htons((uint16_t)(ip->ip_off | IP_MF)); |
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ip->ip_sum = 0;
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ip->ip_sum = cksum(m, hlen); |
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sendorfree:
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for (m = m0; m; m = m0) {
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m0 = m->m_nextpkt; |
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m->m_nextpkt = NULL;
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if (error == 0) |
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if_output(so, m); |
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else
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m_free(m); |
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} |
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} |
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done:
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return (error);
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bad:
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m_free(m0); |
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goto done;
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} |