/*
* Free a fragment reassembly header and all
* associated datagrams.
*/
void ip_freef(struct ipq *fp)
{
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));
}
static int
tcp_reass(register struct tcpcb *tp, register struct tcpiphdr *ti,
struct mbuf *m)
{
register struct tcpiphdr *q;
struct socket *so = tp->t_socket;
int flags;
/*
* Call with ti==0 after become established to
* force pre-ESTABLISHED data up to user socket.
*/
if (ti == 0)
goto present;
/*
* Find a segment which begins after this one does.
*/
for (q = (struct tcpiphdr *)tp->seg_next; q != (struct tcpiphdr *)tp;
q = (struct tcpiphdr *)q->ti_next)
if (SEQ_GT(q->ti_seq, ti->ti_seq))
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 ((struct tcpiphdr *)q->ti_prev != (struct tcpiphdr *)tp) {
register int i;
q = (struct tcpiphdr *)q->ti_prev;
/* conversion to int (in i) handles seq wraparound */
i = q->ti_seq + q->ti_len - ti->ti_seq;
if (i > 0) {
if (i >= ti->ti_len) {
STAT(tcpstat.tcps_rcvduppack++);
STAT(tcpstat.tcps_rcvdupbyte += ti->ti_len);
m_freem(m);
/*
* Try to present any queued data
* at the left window edge to the user.
* This is needed after the 3-WHS
* completes.
*/
goto present; /* ??? */
}
m_adj(m, i);
ti->ti_len -= i;
ti->ti_seq += i;
}
q = (struct tcpiphdr *)(q->ti_next);
}
STAT(tcpstat.tcps_rcvoopack++);
STAT(tcpstat.tcps_rcvoobyte += ti->ti_len);
REASS_MBUF(ti) = (mbufp_32) m; /* XXX */
/*
* While we overlap succeeding segments trim them or,
* if they are completely covered, dequeue them.
*/
while (q != (struct tcpiphdr *)tp) {
register int i = (ti->ti_seq + ti->ti_len) - q->ti_seq;
if (i <= 0)
break;
if (i < q->ti_len) {
q->ti_seq += i;
q->ti_len -= i;
m_adj((struct mbuf *) REASS_MBUF(q), i);
break;
}
q = (struct tcpiphdr *)q->ti_next;
m = (struct mbuf *) REASS_MBUF((struct tcpiphdr *)q->ti_prev);
remque_32((void *)(q->ti_prev));
m_freem(m);
}
/*
* Stick new segment in its place.
*/
insque_32(ti, (void *)(q->ti_prev));
present:
/*
* Present data to user, advancing rcv_nxt through
* completed sequence space.
*/
if (!TCPS_HAVEESTABLISHED(tp->t_state))
return (0);
ti = (struct tcpiphdr *) tp->seg_next;
if (ti == (struct tcpiphdr *)tp || ti->ti_seq != tp->rcv_nxt)
return (0);
if (tp->t_state == TCPS_SYN_RECEIVED && ti->ti_len)
return (0);
do {
tp->rcv_nxt += ti->ti_len;
flags = ti->ti_flags & TH_FIN;
remque_32(ti);
m = (struct mbuf *) REASS_MBUF(ti); /* XXX */
ti = (struct tcpiphdr *)ti->ti_next;
/* if (so->so_state & SS_FCANTRCVMORE) */
if (so->so_state & SS_FCANTSENDMORE)
m_freem(m);
else {
if (so->so_emu) {
if (tcp_emu(so,m)) sbappend(so, m);
} else
sbappend(so, m);
}
} while (ti != (struct tcpiphdr *)tp && ti->ti_seq == tp->rcv_nxt);
/* sorwakeup(so); */
return (flags);
}
/*
* 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(struct ipasfrag *ip, struct ipq *fp)
{
struct mbuf *m = dtom(ip);
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);
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.
*/
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);
}
