diff options
Diffstat (limited to 'slirp/ip_input.c')
| -rw-r--r-- | slirp/ip_input.c | 697 |
1 files changed, 697 insertions, 0 deletions
diff --git a/slirp/ip_input.c b/slirp/ip_input.c new file mode 100644 index 0000000000..74b9223160 --- /dev/null +++ b/slirp/ip_input.c @@ -0,0 +1,697 @@ +/* + * 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 + * 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" + +int ip_defttl; +struct ipstat ipstat; +struct ipq ipq; + +/* + * IP initialization: fill in IP protocol switch table. + * All protocols not implemented in kernel go to raw IP protocol handler. + */ +void +ip_init() +{ + ipq.next = ipq.prev = (ipqp_32)&ipq; + ip_id = tt.tv_sec & 0xffff; + udp_init(); + tcp_init(); + ip_defttl = IPDEFTTL; +} + +/* + * Ip input routine. Checksum and byte swap header. If fragmented + * try to reassemble. Process options. Pass to next level. + */ +void +ip_input(m) + struct mbuf *m; +{ + register struct ip *ip; + int hlen; + + DEBUG_CALL("ip_input"); + DEBUG_ARG("m = %lx", (long)m); + DEBUG_ARG("m_len = %d", m->m_len); + + ipstat.ips_total++; + + if (m->m_len < sizeof (struct ip)) { + 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 ) || hlen>m->m_len) {/* min header length */ + ipstat.ips_badhlen++; /* or packet too short */ + goto bad; + } + + /* keep ip header intact for ICMP reply + * ip->ip_sum = cksum(m, hlen); + * if (ip->ip_sum) { + */ + if(cksum(m,hlen)) { + 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_len < ip->ip_len) { + ipstat.ips_tooshort++; + 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 || ip->ip_ttl==1) { + icmp_error(m, ICMP_TIMXCEED,ICMP_TIMXCEED_INTRANS, 0,"ttl"); + goto bad; + } + + /* + * 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). + */ +/* We do no IP options */ +/* if (hlen > sizeof (struct ip) && ip_dooptions(m)) + * goto next; + */ + /* + * 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; + /* + * Look for queue of fragments + * of this datagram. + */ + for (fp = (struct ipq *) ipq.next; fp != &ipq; + fp = (struct ipq *) 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; + if (ip->ip_off & IP_MF) + ((struct ipasfrag *)ip)->ipf_mff |= 1; + else + ((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) + return; + ipstat.ips_reassembled++; + m = dtom(ip); + } else + if (fp) + ip_freef(fp); + + } else + ip->ip_len -= hlen; + + /* + * Switch out to protocol's input routine. + */ + ipstat.ips_delivered++; + 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: + ipstat.ips_noproto++; + m_free(m); + } + return; +bad: + m_freem(m); + return; +} + +/* + * 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. + */ +struct ip * +ip_reass(ip, fp) + register struct ipasfrag *ip; + register struct ipq *fp; +{ + register struct mbuf *m = dtom(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 == 0) { + struct mbuf *t; + if ((t = m_get()) == NULL) goto dropfrag; + fp = mtod(t, struct ipq *); + insque_32(fp, &ipq); + fp->ipq_ttl = IPFRAGTTL; + fp->ipq_p = ip->ip_p; + fp->ipq_id = ip->ip_id; + fp->ipq_next = fp->ipq_prev = (ipasfragp_32)fp; + fp->ipq_src = ((struct ip *)ip)->ip_src; + fp->ipq_dst = ((struct ip *)ip)->ip_dst; + q = (struct ipasfrag *)fp; + goto insert; + } + + /* + * Find a segment which begins after this one does. + */ + for (q = (struct ipasfrag *)fp->ipq_next; q != (struct ipasfrag *)fp; + q = (struct ipasfrag *)q->ipf_next) + if (q->ip_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 != (ipasfragp_32)fp) { + i = ((struct ipasfrag *)(q->ipf_prev))->ip_off + + ((struct ipasfrag *)(q->ipf_prev))->ip_len - ip->ip_off; + if (i > 0) { + if (i >= ip->ip_len) + goto dropfrag; + m_adj(dtom(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 && ip->ip_off + ip->ip_len > q->ip_off) { + i = (ip->ip_off + ip->ip_len) - q->ip_off; + if (i < q->ip_len) { + q->ip_len -= i; + q->ip_off += i; + m_adj(dtom(q), i); + break; + } + q = (struct ipasfrag *) q->ipf_next; + m_freem(dtom((struct ipasfrag *) q->ipf_prev)); + ip_deq((struct ipasfrag *) q->ipf_prev); + } + +insert: + /* + * Stick new segment in its place; + * check for complete reassembly. + */ + ip_enq(ip, (struct ipasfrag *) q->ipf_prev); + next = 0; + for (q = (struct ipasfrag *) fp->ipq_next; q != (struct ipasfrag *)fp; + q = (struct ipasfrag *) q->ipf_next) { + if (q->ip_off != next) + return (0); + next += q->ip_len; + } + if (((struct ipasfrag *)(q->ipf_prev))->ipf_mff & 1) + return (0); + + /* + * Reassembly is complete; concatenate fragments. + */ + q = (struct ipasfrag *) fp->ipq_next; + m = dtom(q); + + q = (struct ipasfrag *) q->ipf_next; + while (q != (struct ipasfrag *)fp) { + struct mbuf *t; + t = dtom(q); + m_cat(m, t); + q = (struct ipasfrag *) q->ipf_next; + } + + /* + * Create header for new ip packet by + * modifying header of first packet; + * dequeue and discard fragment reassembly header. + * Make header visible. + */ + ip = (struct ipasfrag *) fp->ipq_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; + delta = (char *)ip - m->m_dat; + ip = (struct ipasfrag *)(m->m_ext + delta); + } + + /* DEBUG_ARG("ip = %lx", (long)ip); + * ip=(struct ipasfrag *)m->m_data; */ + + ip->ip_len = next; + ip->ipf_mff &= ~1; + ((struct ip *)ip)->ip_src = fp->ipq_src; + ((struct ip *)ip)->ip_dst = fp->ipq_dst; + remque_32(fp); + (void) m_free(dtom(fp)); + m = dtom(ip); + m->m_len += (ip->ip_hl << 2); + m->m_data -= (ip->ip_hl << 2); + + return ((struct ip *)ip); + +dropfrag: + ipstat.ips_fragdropped++; + m_freem(m); + return (0); +} + +/* + * Free a fragment reassembly header and all + * associated datagrams. + */ +void +ip_freef(fp) + struct ipq *fp; +{ + register struct ipasfrag *q, *p; + + for (q = (struct ipasfrag *) fp->ipq_next; q != (struct ipasfrag *)fp; + q = p) { + p = (struct ipasfrag *) q->ipf_next; + ip_deq(q); + m_freem(dtom(q)); + } + remque_32(fp); + (void) m_free(dtom(fp)); +} + +/* + * Put an ip fragment on a reassembly chain. + * Like insque, but pointers in middle of structure. + */ +void +ip_enq(p, prev) + register struct ipasfrag *p, *prev; +{ + DEBUG_CALL("ip_enq"); + DEBUG_ARG("prev = %lx", (long)prev); + p->ipf_prev = (ipasfragp_32) prev; + p->ipf_next = prev->ipf_next; + ((struct ipasfrag *)(prev->ipf_next))->ipf_prev = (ipasfragp_32) p; + prev->ipf_next = (ipasfragp_32) p; +} + +/* + * To ip_enq as remque is to insque. + */ +void +ip_deq(p) + 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() +{ + register struct ipq *fp; + + DEBUG_CALL("ip_slowtimo"); + + fp = (struct ipq *) ipq.next; + if (fp == 0) + return; + + while (fp != &ipq) { + --fp->ipq_ttl; + fp = (struct ipq *) fp->next; + if (((struct ipq *)(fp->prev))->ipq_ttl == 0) { + ipstat.ips_fragtimeout++; + ip_freef((struct ipq *) fp->prev); + } + } +} + +/* + * 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 = ICMP_PARAMPROB, forward = 0; */ + int opt, optlen, cnt, off, code, type, forward = 0; + struct in_addr *sin, dst; +typedef u_int32_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: + /* ip->ip_len -= ip->ip_hl << 2; XXX icmp_error adds in hdr length */ + +/* Not yet */ + icmp_error(m, type, code, 0, 0); + + ipstat.ips_badoptions++; + 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(m, mopt) + 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; +} |