#include <machine/rtems-bsd-config.h>
/*-
* Copyright (c) 1982, 1986, 1988, 1990, 1993, 1994, 1995
* 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.
* 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.
*
* @(#)tcp_input.c 8.12 (Berkeley) 5/24/95
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <rtems/bsd/local/opt_inet.h>
#include <rtems/bsd/local/opt_inet6.h>
#include <rtems/bsd/local/opt_tcpdebug.h>
#include <rtems/bsd/sys/param.h>
#include <sys/kernel.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/sysctl.h>
#include <sys/syslog.h>
#include <sys/systm.h>
#include <vm/uma.h>
#include <net/if.h>
#include <net/route.h>
#include <net/vnet.h>
#include <netinet/in.h>
#include <netinet/in_pcb.h>
#include <netinet/in_systm.h>
#include <netinet/in_var.h>
#include <netinet/ip.h>
#include <netinet/ip_var.h>
#include <netinet/ip_options.h>
#include <netinet/ip6.h>
#include <netinet6/in6_pcb.h>
#include <netinet6/ip6_var.h>
#include <netinet6/nd6.h>
#include <netinet/tcp.h>
#include <netinet/tcp_fsm.h>
#include <netinet/tcp_seq.h>
#include <netinet/tcp_timer.h>
#include <netinet/tcp_var.h>
#include <netinet6/tcp6_var.h>
#include <netinet/tcpip.h>
#ifdef TCPDEBUG
#include <netinet/tcp_debug.h>
#endif /* TCPDEBUG */
static int tcp_reass_sysctl_maxseg(SYSCTL_HANDLER_ARGS);
static int tcp_reass_sysctl_qsize(SYSCTL_HANDLER_ARGS);
SYSCTL_NODE(_net_inet_tcp, OID_AUTO, reass, CTLFLAG_RW, 0,
"TCP Segment Reassembly Queue");
static VNET_DEFINE(int, tcp_reass_maxseg) = 0;
#define V_tcp_reass_maxseg VNET(tcp_reass_maxseg)
SYSCTL_VNET_PROC(_net_inet_tcp_reass, OID_AUTO, maxsegments,
CTLTYPE_INT | CTLFLAG_RDTUN,
&VNET_NAME(tcp_reass_maxseg), 0, &tcp_reass_sysctl_maxseg, "I",
"Global maximum number of TCP Segments in Reassembly Queue");
static VNET_DEFINE(int, tcp_reass_qsize) = 0;
#define V_tcp_reass_qsize VNET(tcp_reass_qsize)
SYSCTL_VNET_PROC(_net_inet_tcp_reass, OID_AUTO, cursegments,
CTLTYPE_INT | CTLFLAG_RD,
&VNET_NAME(tcp_reass_qsize), 0, &tcp_reass_sysctl_qsize, "I",
"Global number of TCP Segments currently in Reassembly Queue");
static VNET_DEFINE(int, tcp_reass_overflows) = 0;
#define V_tcp_reass_overflows VNET(tcp_reass_overflows)
SYSCTL_VNET_INT(_net_inet_tcp_reass, OID_AUTO, overflows,
CTLTYPE_INT | CTLFLAG_RD,
&VNET_NAME(tcp_reass_overflows), 0,
"Global number of TCP Segment Reassembly Queue Overflows");
static VNET_DEFINE(uma_zone_t, tcp_reass_zone);
#define V_tcp_reass_zone VNET(tcp_reass_zone)
/* Initialize TCP reassembly queue */
static void
tcp_reass_zone_change(void *tag)
{
V_tcp_reass_maxseg = nmbclusters / 16;
uma_zone_set_max(V_tcp_reass_zone, V_tcp_reass_maxseg);
}
void
tcp_reass_init(void)
{
V_tcp_reass_maxseg = nmbclusters / 16;
TUNABLE_INT_FETCH("net.inet.tcp.reass.maxsegments",
&V_tcp_reass_maxseg);
V_tcp_reass_zone = uma_zcreate("tcpreass", sizeof (struct tseg_qent),
NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE);
uma_zone_set_max(V_tcp_reass_zone, V_tcp_reass_maxseg);
EVENTHANDLER_REGISTER(nmbclusters_change,
tcp_reass_zone_change, NULL, EVENTHANDLER_PRI_ANY);
}
#ifdef VIMAGE
void
tcp_reass_destroy(void)
{
uma_zdestroy(V_tcp_reass_zone);
}
#endif
void
tcp_reass_flush(struct tcpcb *tp)
{
struct tseg_qent *qe;
INP_WLOCK_ASSERT(tp->t_inpcb);
while ((qe = LIST_FIRST(&tp->t_segq)) != NULL) {
LIST_REMOVE(qe, tqe_q);
m_freem(qe->tqe_m);
uma_zfree(V_tcp_reass_zone, qe);
tp->t_segqlen--;
}
KASSERT((tp->t_segqlen == 0),
("TCP reass queue %p segment count is %d instead of 0 after flush.",
tp, tp->t_segqlen));
}
static int
tcp_reass_sysctl_maxseg(SYSCTL_HANDLER_ARGS)
{
V_tcp_reass_maxseg = uma_zone_get_max(V_tcp_reass_zone);
return (sysctl_handle_int(oidp, arg1, arg2, req));
}
static int
tcp_reass_sysctl_qsize(SYSCTL_HANDLER_ARGS)
{
V_tcp_reass_qsize = uma_zone_get_cur(V_tcp_reass_zone);
return (sysctl_handle_int(oidp, arg1, arg2, req));
}
int
tcp_reass(struct tcpcb *tp, struct tcphdr *th, int *tlenp, struct mbuf *m)
{
struct tseg_qent *q;
struct tseg_qent *p = NULL;
struct tseg_qent *nq;
struct tseg_qent *te = NULL;
struct socket *so = tp->t_inpcb->inp_socket;
char *s = NULL;
int flags;
struct tseg_qent tqs;
INP_WLOCK_ASSERT(tp->t_inpcb);
/*
* XXX: tcp_reass() is rather inefficient with its data structures
* and should be rewritten (see NetBSD for optimizations).
*/
/*
* Call with th==NULL after become established to
* force pre-ESTABLISHED data up to user socket.
*/
if (th == NULL)
goto present;
/*
* Limit the number of segments that can be queued to reduce the
* potential for mbuf exhaustion. For best performance, we want to be
* able to queue a full window's worth of segments. The size of the
* socket receive buffer determines our advertised window and grows
* automatically when socket buffer autotuning is enabled. Use it as the
* basis for our queue limit.
* Always let the missing segment through which caused this queue.
* NB: Access to the socket buffer is left intentionally unlocked as we
* can tolerate stale information here.
*
* XXXLAS: Using sbspace(so->so_rcv) instead of so->so_rcv.sb_hiwat
* should work but causes packets to be dropped when they shouldn't.
* Investigate why and re-evaluate the below limit after the behaviour
* is understood.
*/
if (th->th_seq != tp->rcv_nxt &&
tp->t_segqlen >= (so->so_rcv.sb_hiwat / tp->t_maxseg) + 1) {
V_tcp_reass_overflows++;
TCPSTAT_INC(tcps_rcvmemdrop);
m_freem(m);
*tlenp = 0;
if ((s = tcp_log_addrs(&tp->t_inpcb->inp_inc, th, NULL, NULL))) {
log(LOG_DEBUG, "%s; %s: queue limit reached, "
"segment dropped\n", s, __func__);
free(s, M_TCPLOG);
}
return (0);
}
/*
* Allocate a new queue entry. If we can't, or hit the zone limit
* just drop the pkt.
*
* Use a temporary structure on the stack for the missing segment
* when the zone is exhausted. Otherwise we may get stuck.
*/
te = uma_zalloc(V_tcp_reass_zone, M_NOWAIT);
if (te == NULL) {
if (th->th_seq != tp->rcv_nxt) {
TCPSTAT_INC(tcps_rcvmemdrop);
m_freem(m);
*tlenp = 0;
if ((s = tcp_log_addrs(&tp->t_inpcb->inp_inc, th, NULL,
NULL))) {
log(LOG_DEBUG, "%s; %s: global zone limit "
"reached, segment dropped\n", s, __func__);
free(s, M_TCPLOG);
}
return (0);
} else {
bzero(&tqs, sizeof(struct tseg_qent));
te = &tqs;
if ((s = tcp_log_addrs(&tp->t_inpcb->inp_inc, th, NULL,
NULL))) {
log(LOG_DEBUG,
"%s; %s: global zone limit reached, using "
"stack for missing segment\n", s, __func__);
free(s, M_TCPLOG);
}
}
}
tp->t_segqlen++;
/*
* Find a segment which begins after this one does.
*/
LIST_FOREACH(q, &tp->t_segq, tqe_q) {
if (SEQ_GT(q->tqe_th->th_seq, th->th_seq))
break;
p = q;
}
/*
* 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 (p != NULL) {
int i;
/* conversion to int (in i) handles seq wraparound */
i = p->tqe_th->th_seq + p->tqe_len - th->th_seq;
if (i > 0) {
if (i >= *tlenp) {
TCPSTAT_INC(tcps_rcvduppack);
TCPSTAT_ADD(tcps_rcvdupbyte, *tlenp);
m_freem(m);
uma_zfree(V_tcp_reass_zone, te);
tp->t_segqlen--;
/*
* 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);
*tlenp -= i;
th->th_seq += i;
}
}
tp->t_rcvoopack++;
TCPSTAT_INC(tcps_rcvoopack);
TCPSTAT_ADD(tcps_rcvoobyte, *tlenp);
/*
* While we overlap succeeding segments trim them or,
* if they are completely covered, dequeue them.
*/
while (q) {
int i = (th->th_seq + *tlenp) - q->tqe_th->th_seq;
if (i <= 0)
break;
if (i < q->tqe_len) {
q->tqe_th->th_seq += i;
q->tqe_len -= i;
m_adj(q->tqe_m, i);
break;
}
nq = LIST_NEXT(q, tqe_q);
LIST_REMOVE(q, tqe_q);
m_freem(q->tqe_m);
uma_zfree(V_tcp_reass_zone, q);
tp->t_segqlen--;
q = nq;
}
/* Insert the new segment queue entry into place. */
te->tqe_m = m;
te->tqe_th = th;
te->tqe_len = *tlenp;
if (p == NULL) {
LIST_INSERT_HEAD(&tp->t_segq, te, tqe_q);
} else {
KASSERT(te != &tqs, ("%s: temporary stack based entry not "
"first element in queue", __func__));
LIST_INSERT_AFTER(p, te, tqe_q);
}
present:
/*
* Present data to user, advancing rcv_nxt through
* completed sequence space.
*/
if (!TCPS_HAVEESTABLISHED(tp->t_state))
return (0);
q = LIST_FIRST(&tp->t_segq);
if (!q || q->tqe_th->th_seq != tp->rcv_nxt)
return (0);
SOCKBUF_LOCK(&so->so_rcv);
do {
tp->rcv_nxt += q->tqe_len;
flags = q->tqe_th->th_flags & TH_FIN;
nq = LIST_NEXT(q, tqe_q);
LIST_REMOVE(q, tqe_q);
if (so->so_rcv.sb_state & SBS_CANTRCVMORE)
m_freem(q->tqe_m);
else
sbappendstream_locked(&so->so_rcv, q->tqe_m);
if (q != &tqs)
uma_zfree(V_tcp_reass_zone, q);
tp->t_segqlen--;
q = nq;
} while (q && q->tqe_th->th_seq == tp->rcv_nxt);
ND6_HINT(tp);
sorwakeup_locked(so);
return (flags);
}
