o Move all parts of the IP reassembly process into the function ip_reass() to
make it fully self-contained. o ip_reass() now returns a new mbuf with the reassembled packet and ip->ip_len including the IP header. o Computation of the delayed checksum is moved into divert_packet(). Reviewed by: silby
This commit is contained in:
Andre Oppermann
parent
39958d87d2
commit
f0cada84b1
Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=133069
@ -168,6 +168,14 @@ divert_packet(struct mbuf *m, int incoming)
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return;
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ip = mtod(m, struct ip *);
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/* Delayed checksums are currently not compatible with divert. */
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if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
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ip->ip_len = ntohs(ip->ip_len);
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in_delayed_cksum(m);
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m->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
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ip->ip_len = htons(ip->ip_len);
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}
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/*
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* Record receive interface address, if any.
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* But only for incoming packets.
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@ -240,7 +240,7 @@ static int ip_dooptions(struct mbuf *m, int,
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static void ip_forward(struct mbuf *m, int srcrt,
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struct sockaddr_in *next_hop);
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static void ip_freef(struct ipqhead *, struct ipq *);
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static struct mbuf *ip_reass(struct mbuf *, struct ipqhead *, struct ipq *);
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static struct mbuf *ip_reass(struct mbuf *);
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/*
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* IP initialization: fill in IP protocol switch table.
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@ -296,7 +296,6 @@ void
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ip_input(struct mbuf *m)
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{
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struct ip *ip = NULL;
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struct ipq *fp;
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struct in_ifaddr *ia = NULL;
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struct ifaddr *ifa;
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int i, checkif, hlen = 0;
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@ -726,103 +725,19 @@ ip_input(struct mbuf *m)
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}
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/*
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* If offset or IP_MF are set, must reassemble.
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* Otherwise, nothing need be done.
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* (We could look in the reassembly queue to see
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* if the packet was previously fragmented,
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* but it's not worth the time; just let them time out.)
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* Attempt reassembly; if it succeeds, proceed.
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* ip_reass() will return a different mbuf.
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*/
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if (ip->ip_off & (IP_MF | IP_OFFMASK)) {
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/* If maxnipq is 0, never accept fragments. */
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if (maxnipq == 0) {
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ipstat.ips_fragments++;
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ipstat.ips_fragdropped++;
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goto bad;
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}
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sum = IPREASS_HASH(ip->ip_src.s_addr, ip->ip_id);
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IPQ_LOCK();
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/*
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* Look for queue of fragments
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* of this datagram.
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*/
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TAILQ_FOREACH(fp, &ipq[sum], ipq_list)
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if (ip->ip_id == fp->ipq_id &&
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ip->ip_src.s_addr == fp->ipq_src.s_addr &&
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ip->ip_dst.s_addr == fp->ipq_dst.s_addr &&
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#ifdef MAC
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mac_fragment_match(m, fp) &&
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#endif
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ip->ip_p == fp->ipq_p)
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goto found;
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fp = NULL;
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/*
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* Enforce upper bound on number of fragmented packets
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* for which we attempt reassembly;
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* If maxnipq is -1, accept all fragments without limitation.
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*/
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if ((nipq > maxnipq) && (maxnipq > 0)) {
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/*
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* drop something from the tail of the current queue
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* before proceeding further
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*/
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struct ipq *q = TAILQ_LAST(&ipq[sum], ipqhead);
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if (q == NULL) { /* gak */
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for (i = 0; i < IPREASS_NHASH; i++) {
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struct ipq *r = TAILQ_LAST(&ipq[i], ipqhead);
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if (r) {
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ipstat.ips_fragtimeout += r->ipq_nfrags;
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ip_freef(&ipq[i], r);
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break;
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}
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}
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} else {
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ipstat.ips_fragtimeout += q->ipq_nfrags;
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ip_freef(&ipq[sum], q);
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}
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}
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found:
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/*
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* Adjust ip_len to not reflect header,
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* convert offset of this to bytes.
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*/
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ip->ip_len -= hlen;
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if (ip->ip_off & IP_MF) {
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/*
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* Make sure that fragments have a data length
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* that's a non-zero multiple of 8 bytes.
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*/
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if (ip->ip_len == 0 || (ip->ip_len & 0x7) != 0) {
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IPQ_UNLOCK();
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ipstat.ips_toosmall++; /* XXX */
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goto bad;
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}
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m->m_flags |= M_FRAG;
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} else
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m->m_flags &= ~M_FRAG;
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ip->ip_off <<= 3;
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/*
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* Attempt reassembly; if it succeeds, proceed.
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* ip_reass() will return a different mbuf.
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*/
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ipstat.ips_fragments++;
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m->m_pkthdr.header = ip;
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m = ip_reass(m, &ipq[sum], fp);
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IPQ_UNLOCK();
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if (m == 0)
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m = ip_reass(m);
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if (m == NULL)
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return;
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ipstat.ips_reassembled++;
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ip = mtod(m, struct ip *);
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/* Get the header length of the reassembled packet */
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hlen = ip->ip_hl << 2;
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#ifdef IPDIVERT
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/* Restore original checksum before diverting packet */
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if (divert_find_info(m) != 0) {
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ip->ip_len += hlen;
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ip->ip_len = htons(ip->ip_len);
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ip->ip_off = htons(ip->ip_off);
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ip->ip_sum = 0;
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@ -832,11 +747,15 @@ ip_input(struct mbuf *m)
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ip->ip_sum = in_cksum(m, hlen);
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ip->ip_off = ntohs(ip->ip_off);
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ip->ip_len = ntohs(ip->ip_len);
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ip->ip_len -= hlen;
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}
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#endif
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} else
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ip->ip_len -= hlen;
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}
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/*
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* Further protocols expect the packet length to be w/o the
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* IP header.
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*/
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ip->ip_len -= hlen;
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#ifdef IPDIVERT
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/*
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@ -951,27 +870,112 @@ DPRINTF(("ip_input: no SP, packet discarded\n"));/*XXX*/
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/*
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* Take incoming datagram fragment and try to reassemble it into
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* whole datagram. If a chain for reassembly of this datagram already
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* exists, then it is given as fp; otherwise have to make a chain.
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*
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* When IPDIVERT enabled, keep additional state with each packet that
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* tells us if we need to divert or tee the packet we're building.
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* In particular, *divinfo includes the port and TEE flag,
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* *divert_rule is the number of the matching rule.
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* whole datagram. If the argument is the first fragment or one
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* in between the function will return NULL and store the mbuf
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* in the fragment chain. If the argument is the last fragment
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* the packet will be reassembled and the pointer to the new
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* mbuf returned for further processing. Only m_tags attached
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* to the first packet/fragment are preserved.
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* The IP header is *NOT* adjusted out of iplen.
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*/
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static struct mbuf *
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ip_reass(struct mbuf *m, struct ipqhead *head, struct ipq *fp)
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struct mbuf *
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ip_reass(struct mbuf *m)
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{
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struct ip *ip = mtod(m, struct ip *);
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register struct mbuf *p, *q, *nq;
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struct mbuf *t;
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int hlen = ip->ip_hl << 2;
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int i, next;
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struct ip *ip;
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struct mbuf *p, *q, *nq, *t;
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struct ipq *fp = NULL;
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struct ipqhead *head;
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int i, hlen, next;
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u_int8_t ecn, ecn0;
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u_short hash;
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IPQ_LOCK_ASSERT();
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/* If maxnipq is 0, never accept fragments. */
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if (maxnipq == 0) {
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ipstat.ips_fragments++;
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ipstat.ips_fragdropped++;
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goto dropfrag;
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}
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ip = mtod(m, struct ip *);
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hlen = ip->ip_hl << 2;
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hash = IPREASS_HASH(ip->ip_src.s_addr, ip->ip_id);
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head = &ipq[hash];
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IPQ_LOCK();
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/*
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* Look for queue of fragments
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* of this datagram.
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*/
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TAILQ_FOREACH(fp, head, ipq_list)
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if (ip->ip_id == fp->ipq_id &&
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ip->ip_src.s_addr == fp->ipq_src.s_addr &&
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ip->ip_dst.s_addr == fp->ipq_dst.s_addr &&
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#ifdef MAC
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mac_fragment_match(m, fp) &&
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#endif
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ip->ip_p == fp->ipq_p)
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goto found;
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fp = NULL;
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/*
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* Enforce upper bound on number of fragmented packets
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* for which we attempt reassembly;
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* If maxnipq is -1, accept all fragments without limitation.
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*/
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if ((nipq > maxnipq) && (maxnipq > 0)) {
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/*
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* drop something from the tail of the current queue
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* before proceeding further
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*/
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struct ipq *q = TAILQ_LAST(head, ipqhead);
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if (q == NULL) { /* gak */
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for (i = 0; i < IPREASS_NHASH; i++) {
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struct ipq *r = TAILQ_LAST(&ipq[i], ipqhead);
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if (r) {
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ipstat.ips_fragtimeout += r->ipq_nfrags;
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ip_freef(&ipq[i], r);
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break;
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}
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}
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} else {
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ipstat.ips_fragtimeout += q->ipq_nfrags;
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ip_freef(head, q);
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}
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}
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found:
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/*
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* Adjust ip_len to not reflect header,
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* convert offset of this to bytes.
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*/
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ip->ip_len -= hlen;
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if (ip->ip_off & IP_MF) {
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/*
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* Make sure that fragments have a data length
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* that's a non-zero multiple of 8 bytes.
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*/
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if (ip->ip_len == 0 || (ip->ip_len & 0x7) != 0) {
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IPQ_UNLOCK();
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ipstat.ips_toosmall++; /* XXX */
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goto dropfrag;
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}
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m->m_flags |= M_FRAG;
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} else
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m->m_flags &= ~M_FRAG;
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ip->ip_off <<= 3;
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/*
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* Attempt reassembly; if it succeeds, proceed.
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* ip_reass() will return a different mbuf.
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*/
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ipstat.ips_fragments++;
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m->m_pkthdr.header = ip;
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/* Previous ip_reass() started here. */
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/*
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* Presence of header sizes in mbufs
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* would confuse code below.
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@ -1114,7 +1118,7 @@ ip_reass(struct mbuf *m, struct ipqhead *head, struct ipq *fp)
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ipstat.ips_fragdropped += fp->ipq_nfrags;
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ip_freef(head, fp);
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}
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return (0);
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goto done;
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}
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next += GETIP(q)->ip_len;
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}
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@ -1124,7 +1128,7 @@ ip_reass(struct mbuf *m, struct ipqhead *head, struct ipq *fp)
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ipstat.ips_fragdropped += fp->ipq_nfrags;
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ip_freef(head, fp);
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}
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return (0);
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goto done;
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}
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/*
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@ -1136,7 +1140,7 @@ ip_reass(struct mbuf *m, struct ipqhead *head, struct ipq *fp)
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ipstat.ips_toolong++;
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ipstat.ips_fragdropped += fp->ipq_nfrags;
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ip_freef(head, fp);
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return (0);
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goto done;
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}
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/*
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@ -1161,12 +1165,11 @@ ip_reass(struct mbuf *m, struct ipqhead *head, struct ipq *fp)
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#endif
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/*
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* Create header for new ip packet by
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* modifying header of first packet;
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* dequeue and discard fragment reassembly header.
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* Create header for new ip packet by modifying header of first
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* packet; dequeue and discard fragment reassembly header.
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* Make header visible.
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*/
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ip->ip_len = next;
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ip->ip_len = (ip->ip_hl << 2) + next;
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ip->ip_src = fp->ipq_src;
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ip->ip_dst = fp->ipq_dst;
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TAILQ_REMOVE(head, fp, ipq_list);
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@ -1177,6 +1180,8 @@ ip_reass(struct mbuf *m, struct ipqhead *head, struct ipq *fp)
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/* some debugging cruft by sklower, below, will go away soon */
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if (m->m_flags & M_PKTHDR) /* XXX this should be done elsewhere */
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m_fixhdr(m);
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ipstat.ips_reassembled++;
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IPQ_UNLOCK();
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return (m);
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dropfrag:
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@ -1184,7 +1189,9 @@ ip_reass(struct mbuf *m, struct ipqhead *head, struct ipq *fp)
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if (fp != NULL)
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fp->ipq_nfrags--;
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m_freem(m);
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return (0);
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done:
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IPQ_UNLOCK();
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return (NULL);
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#undef GETIP
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}
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