*
* @APPLE_LICENSE_HEADER_START@
*
- * Copyright (c) 1999-2003 Apple Computer, Inc. All Rights Reserved.
+ * The contents of this file constitute Original Code as defined in and
+ * are subject to the Apple Public Source License Version 1.1 (the
+ * "License"). You may not use this file except in compliance with the
+ * License. Please obtain a copy of the License at
+ * http://www.apple.com/publicsource and read it before using this file.
*
- * This file contains Original Code and/or Modifications of Original Code
- * as defined in and that are subject to the Apple Public Source License
- * Version 2.0 (the 'License'). You may not use this file except in
- * compliance with the License. Please obtain a copy of the License at
- * http://www.opensource.apple.com/apsl/ and read it before using this
- * file.
- *
- * The Original Code and all software distributed under the License are
- * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
+ * This Original Code and all software distributed under the License are
+ * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
- * Please see the License for the specific language governing rights and
- * limitations under the License.
+ * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT. Please see the
+ * License for the specific language governing rights and limitations
+ * under the License.
*
* @APPLE_LICENSE_HEADER_END@
*/
#if IPSEC
extern int ipsec_bypass;
+extern lck_mtx_t *sadb_mutex;
#endif
struct tcpstat tcpstat;
SYSCTL_INT(_net_inet_tcp, OID_AUTO, blackhole, CTLFLAG_RW,
&blackhole, 0, "Do not send RST when dropping refused connections");
-int tcp_delack_enabled = 1;
+int tcp_delack_enabled = 3;
SYSCTL_INT(_net_inet_tcp, OID_AUTO, delayed_ack, CTLFLAG_RW,
&tcp_delack_enabled, 0,
"Delay ACK to try and piggyback it onto a data packet");
"Listen Queue Overflow");
#if TCP_DROP_SYNFIN
-static int drop_synfin = 0;
+static int drop_synfin = 1;
SYSCTL_INT(_net_inet_tcp, OID_AUTO, drop_synfin, CTLFLAG_RW,
&drop_synfin, 0, "Drop TCP packets with SYN+FIN set");
#endif
+SYSCTL_NODE(_net_inet_tcp, OID_AUTO, reass, CTLFLAG_RW, 0,
+ "TCP Segment Reassembly Queue");
+
+__private_extern__ int tcp_reass_maxseg = 0;
+SYSCTL_INT(_net_inet_tcp_reass, OID_AUTO, maxsegments, CTLFLAG_RW,
+ &tcp_reass_maxseg, 0,
+ "Global maximum number of TCP Segments in Reassembly Queue");
+
+__private_extern__ int tcp_reass_qsize = 0;
+SYSCTL_INT(_net_inet_tcp_reass, OID_AUTO, cursegments, CTLFLAG_RD,
+ &tcp_reass_qsize, 0,
+ "Global number of TCP Segments currently in Reassembly Queue");
+
+static int tcp_reass_overflows = 0;
+SYSCTL_INT(_net_inet_tcp_reass, OID_AUTO, overflows, CTLFLAG_RD,
+ &tcp_reass_overflows, 0,
+ "Global number of TCP Segment Reassembly Queue Overflows");
+
+
__private_extern__ int slowlink_wsize = 8192;
SYSCTL_INT(_net_inet_tcp, OID_AUTO, slowlink_wsize, CTLFLAG_RW,
&slowlink_wsize, 0, "Maximum advertised window size for slowlink");
#define tcb6 tcb /* for KAME src sync over BSD*'s */
struct inpcbinfo tcbinfo;
-static void tcp_dooptions __P((struct tcpcb *,
- u_char *, int, struct tcphdr *, struct tcpopt *));
-static void tcp_pulloutofband __P((struct socket *,
- struct tcphdr *, struct mbuf *, int));
-static int tcp_reass __P((struct tcpcb *, struct tcphdr *, int *,
- struct mbuf *));
-static void tcp_xmit_timer __P((struct tcpcb *, int));
-static int tcp_newreno __P((struct tcpcb *, struct tcphdr *));
+static void tcp_dooptions(struct tcpcb *,
+ u_char *, int, struct tcphdr *, struct tcpopt *);
+static void tcp_pulloutofband(struct socket *,
+ struct tcphdr *, struct mbuf *, int);
+static int tcp_reass(struct tcpcb *, struct tcphdr *, int *,
+ struct mbuf *);
+static void tcp_xmit_timer(struct tcpcb *, int);
+static int tcp_newreno __P((struct tcpcb *, struct tcphdr *));
/* Neighbor Discovery, Neighbor Unreachability Detection Upper layer hint. */
#if INET6
extern u_long *delack_bitmask;
+extern void ipfwsyslog( int level, char *format,...);
+extern int ChkAddressOK( __uint32_t dstaddr, __uint32_t srcaddr );
+extern int fw_verbose;
+
+#define log_in_vain_log( a ) { \
+ if ( (log_in_vain == 3 ) && (fw_verbose == 2)) { /* Apple logging, log to ipfw.log */ \
+ ipfwsyslog a ; \
+ } \
+ else log a ; \
+}
+
/*
- * Indicate whether this ack should be delayed. We can delay the ack if
- * - delayed acks are enabled and
- * - there is no delayed ack timer in progress and
+ * Indicate whether this ack should be delayed.
+ * We can delay the ack if:
+ * - delayed acks are enabled (set to 1) and
* - our last ack wasn't a 0-sized window. We never want to delay
- * the ack that opens up a 0-sized window.
+ * the ack that opens up a 0-sized window.
+ * - delayed acks are enabled (set to 2, "more compatible") and
+ * - our last ack wasn't a 0-sized window.
+ * - if the peer hasn't sent us a TH_PUSH data packet (this solves 3649245)
+ * - the peer hasn't sent us a TH_PUSH data packet, if he did, take this as a clue that we
+ * need to ACK with no delay. This helps higher level protocols who won't send
+ * us more data even if the window is open because their last "segment" hasn't been ACKed
+ * - delayed acks are enabled (set to 3, "streaming detection") and
+ * - if we receive more than 4 full packets per second on this socket, we're streaming acts as "1".
+ * - if we don't meet that criteria, acts like "2". Allowing faster acking while browsing for example.
+ *
*/
#define DELAY_ACK(tp) \
- (tcp_delack_enabled && !callout_pending(tp->tt_delack) && \
- (tp->t_flags & TF_RXWIN0SENT) == 0)
+ (((tcp_delack_enabled == 1) && ((tp->t_flags & TF_RXWIN0SENT) == 0)) || \
+ (((tcp_delack_enabled == 2) && (tp->t_flags & TF_RXWIN0SENT) == 0) && \
+ ((thflags & TH_PUSH) == 0) && ((tp->t_flags & TF_DELACK) == 0)) || \
+ (((tcp_delack_enabled == 3) && (tp->t_flags & TF_RXWIN0SENT) == 0) && \
+ (((tp->t_rcvtime == 0) && (tp->rcv_byps > (4* tp->t_maxseg))) || (((thflags & TH_PUSH) == 0) && ((tp->t_flags & TF_DELACK) == 0)))))
+
+
+static int tcpdropdropablreq(struct socket *head);
static int
struct tseg_qent *te;
struct socket *so = tp->t_inpcb->inp_socket;
int flags;
+ int dowakeup = 0;
/*
* Call with th==0 after become established to
if (th == 0)
goto present;
+ /*
+ * Limit the number of segments in the reassembly queue to prevent
+ * holding on to too many segments (and thus running out of mbufs).
+ * Make sure to let the missing segment through which caused this
+ * queue. Always keep one global queue entry spare to be able to
+ * process the missing segment.
+ */
+ if (th->th_seq != tp->rcv_nxt &&
+ tcp_reass_qsize + 1 >= tcp_reass_maxseg) {
+ tcp_reass_overflows++;
+ tcpstat.tcps_rcvmemdrop++;
+ m_freem(m);
+ return (0);
+ }
+
/* Allocate a new queue entry. If we can't, just drop the pkt. XXX */
MALLOC(te, struct tseg_qent *, sizeof (struct tseg_qent), M_TSEGQ,
M_NOWAIT);
m_freem(m);
return (0);
}
+ tcp_reass_qsize++;
/*
* Find a segment which begins after this one does.
tcpstat.tcps_rcvdupbyte += *tlenp;
m_freem(m);
FREE(te, M_TSEGQ);
+ tcp_reass_qsize--;
/*
* Try to present any queued data
* at the left window edge to the user.
LIST_REMOVE(q, tqe_q);
m_freem(q->tqe_m);
FREE(q, M_TSEGQ);
+ tcp_reass_qsize--;
q = nq;
}
LIST_REMOVE(q, tqe_q);
if (so->so_state & SS_CANTRCVMORE)
m_freem(q->tqe_m);
- else
- sbappend(&so->so_rcv, q->tqe_m);
+ else {
+ if (sbappend(&so->so_rcv, q->tqe_m))
+ dowakeup = 1;
+ }
FREE(q, M_TSEGQ);
+ tcp_reass_qsize--;
q = nq;
} while (q && q->tqe_th->th_seq == tp->rcv_nxt);
ND6_HINT(tp);
(((tp->t_inpcb->inp_laddr.s_addr & 0xffff) << 16) |
(tp->t_inpcb->inp_faddr.s_addr & 0xffff)),
0,0,0);
- }
- sorwakeup(so);
+ }
+ if (dowakeup)
+ sorwakeup(so); /* done with socket lock held */
return (flags);
}
*/
#if INET6
int
-tcp6_input(mp, offp, proto)
+tcp6_input(mp, offp)
struct mbuf **mp;
- int *offp, proto;
+ int *offp;
{
register struct mbuf *m = *mp;
struct in6_ifaddr *ia6;
- IP6_EXTHDR_CHECK(m, *offp, sizeof(struct tcphdr), IPPROTO_DONE);
+ IP6_EXTHDR_CHECK(m, *offp, sizeof(struct tcphdr), return IPPROTO_DONE);
/*
* draft-itojun-ipv6-tcp-to-anycast
#endif
int dropsocket = 0;
int iss = 0;
+ int nosock = 0;
u_long tiwin;
struct tcpopt to; /* options in this segment */
struct rmxp_tao *taop; /* pointer to our TAO cache entry */
struct rmxp_tao tao_noncached; /* in case there's no cached entry */
+ struct sockaddr_in *next_hop = NULL;
#if TCPDEBUG
short ostate = 0;
#endif
+ struct m_tag *fwd_tag;
+
+ /* Grab info from PACKET_TAG_IPFORWARD tag prepended to the chain. */
+ fwd_tag = m_tag_locate(m, KERNEL_MODULE_TAG_ID, KERNEL_TAG_TYPE_IPFORWARD, NULL);
+ if (fwd_tag != NULL) {
+ struct ip_fwd_tag *ipfwd_tag = (struct ip_fwd_tag *)(fwd_tag+1);
+
+ next_hop = ipfwd_tag->next_hop;
+ m_tag_delete(m, fwd_tag);
+ }
+
#if INET6
struct ip6_hdr *ip6 = NULL;
int isipv6;
tlen = sizeof(*ip6) + ntohs(ip6->ip6_plen) - off0;
if (in6_cksum(m, IPPROTO_TCP, off0, tlen)) {
tcpstat.tcps_rcvbadsum++;
- goto drop;
+ goto dropnosock;
}
th = (struct tcphdr *)((caddr_t)ip6 + off0);
*/
if (IN6_IS_ADDR_UNSPECIFIED(&ip6->ip6_src)) {
/* XXX stat */
- goto drop;
+ goto dropnosock;
}
} else
#endif /* INET6 */
}
if (th->th_sum) {
tcpstat.tcps_rcvbadsum++;
- goto drop;
+ goto dropnosock;
}
#if INET6
/* Re-initialization for later version check */
off = th->th_off << 2;
if (off < sizeof (struct tcphdr) || off > tlen) {
tcpstat.tcps_rcvbadoff++;
- goto drop;
+ goto dropnosock;
}
tlen -= off; /* tlen is used instead of ti->ti_len */
if (off > sizeof (struct tcphdr)) {
#if INET6
if (isipv6) {
- IP6_EXTHDR_CHECK(m, off0, off, );
+ IP6_EXTHDR_CHECK(m, off0, off, return);
ip6 = mtod(m, struct ip6_hdr *);
th = (struct tcphdr *)((caddr_t)ip6 + off0);
} else
* This is incompatible with RFC1644 extensions (T/TCP).
*/
if (drop_synfin && (thflags & (TH_SYN|TH_FIN)) == (TH_SYN|TH_FIN))
- goto drop;
+ goto dropnosock;
#endif
/*
*/
findpcb:
#if IPFIREWALL_FORWARD
- if (ip_fw_fwd_addr != NULL
+ if (next_hop != NULL
#if INET6
&& isipv6 == NULL /* IPv6 support is not yet */
#endif /* INET6 */
/*
* No, then it's new. Try find the ambushing socket
*/
- if (!ip_fw_fwd_addr->sin_port) {
+ if (!next_hop->sin_port) {
inp = in_pcblookup_hash(&tcbinfo, ip->ip_src,
- th->th_sport, ip_fw_fwd_addr->sin_addr,
+ th->th_sport, next_hop->sin_addr,
th->th_dport, 1, m->m_pkthdr.rcvif);
} else {
inp = in_pcblookup_hash(&tcbinfo,
ip->ip_src, th->th_sport,
- ip_fw_fwd_addr->sin_addr,
- ntohs(ip_fw_fwd_addr->sin_port), 1,
+ next_hop->sin_addr,
+ ntohs(next_hop->sin_port), 1,
m->m_pkthdr.rcvif);
}
}
- ip_fw_fwd_addr = NULL;
} else
#endif /* IPFIREWALL_FORWARD */
{
}
#if IPSEC
+ if (ipsec_bypass == 0) {
+ lck_mtx_lock(sadb_mutex);
#if INET6
- if (isipv6) {
- if (ipsec_bypass == 0 && inp != NULL && ipsec6_in_reject_so(m, inp->inp_socket)) {
- ipsec6stat.in_polvio++;
- goto drop;
- }
- } else
+ if (isipv6) {
+ if (inp != NULL && ipsec6_in_reject_so(m, inp->inp_socket)) {
+ ipsec6stat.in_polvio++;
+ lck_mtx_unlock(sadb_mutex);
+ goto dropnosock;
+ }
+ } else
#endif /* INET6 */
- if (ipsec_bypass == 0 && inp != NULL && ipsec4_in_reject_so(m, inp->inp_socket)) {
- ipsecstat.in_polvio++;
- goto drop;
+ if (inp != NULL && ipsec4_in_reject_so(m, inp->inp_socket)) {
+ ipsecstat.in_polvio++;
+ lck_mtx_unlock(sadb_mutex);
+ goto dropnosock;
+ }
+ lck_mtx_unlock(sadb_mutex);
}
#endif /*IPSEC*/
if (inp == NULL) {
if (log_in_vain) {
#if INET6
- char dbuf[INET6_ADDRSTRLEN], sbuf[INET6_ADDRSTRLEN];
+ char dbuf[MAX_IPv6_STR_LEN], sbuf[MAX_IPv6_STR_LEN];
#else /* INET6 */
- char dbuf[4*sizeof "123"], sbuf[4*sizeof "123"];
+ char dbuf[MAX_IPv4_STR_LEN], sbuf[MAX_IPv4_STR_LEN];
#endif /* INET6 */
#if INET6
if (isipv6) {
- strcpy(dbuf, ip6_sprintf(&ip6->ip6_dst));
- strcpy(sbuf, ip6_sprintf(&ip6->ip6_src));
+ inet_ntop(AF_INET6, &ip6->ip6_dst, dbuf, sizeof(dbuf));
+ inet_ntop(AF_INET6, &ip6->ip6_src, sbuf, sizeof(sbuf));
} else
#endif
- {
- strcpy(dbuf, inet_ntoa(ip->ip_dst));
- strcpy(sbuf, inet_ntoa(ip->ip_src));
- }
+ {
+ inet_ntop(AF_INET, &ip->ip_dst, dbuf, sizeof(dbuf));
+ inet_ntop(AF_INET, &ip->ip_src, sbuf, sizeof(sbuf));
+ }
switch (log_in_vain) {
case 1:
if(thflags & TH_SYN)
log(LOG_INFO,
- "Connection attempt to TCP %s:%d from %s:%d\n",
- dbuf, ntohs(th->th_dport),
- sbuf,
- ntohs(th->th_sport));
+ "Connection attempt to TCP %s:%d from %s:%d\n",
+ dbuf, ntohs(th->th_dport),
+ sbuf,
+ ntohs(th->th_sport));
break;
case 2:
log(LOG_INFO,
- "Connection attempt to TCP %s:%d from %s:%d flags:0x%x\n",
- dbuf, ntohs(th->th_dport), sbuf,
- ntohs(th->th_sport), thflags);
+ "Connection attempt to TCP %s:%d from %s:%d flags:0x%x\n",
+ dbuf, ntohs(th->th_dport), sbuf,
+ ntohs(th->th_sport), thflags);
+ break;
+ case 3:
+ if ((thflags & TH_SYN) &&
+ !(m->m_flags & (M_BCAST | M_MCAST)) &&
+#if INET6
+ ((isipv6 && !IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst, &ip6->ip6_src)) ||
+ (!isipv6 && ip->ip_dst.s_addr != ip->ip_src.s_addr))
+#else
+ ip->ip_dst.s_addr != ip->ip_src.s_addr
+#endif
+ )
+ log_in_vain_log((LOG_INFO,
+ "Stealth Mode connection attempt to TCP %s:%d from %s:%d\n",
+ dbuf, ntohs(th->th_dport),
+ sbuf,
+ ntohs(th->th_sport)));
break;
default:
break;
}
}
if (blackhole) {
- switch (blackhole) {
- case 1:
- if (thflags & TH_SYN)
- goto drop;
- break;
- case 2:
- goto drop;
- default:
- goto drop;
- }
+ if (m->m_pkthdr.rcvif && m->m_pkthdr.rcvif->if_type != IFT_LOOP)
+ switch (blackhole) {
+ case 1:
+ if (thflags & TH_SYN)
+ goto dropnosock;
+ break;
+ case 2:
+ goto dropnosock;
+ default:
+ goto dropnosock;
+ }
}
rstreason = BANDLIM_RST_CLOSEDPORT;
- goto dropwithreset;
+ goto dropwithresetnosock;
+ }
+ so = inp->inp_socket;
+ if (so == NULL) {
+ if (in_pcb_checkstate(inp, WNT_RELEASE, 1) == WNT_STOPUSING)
+ inp = NULL; // pretend we didn't find it
+#if TEMPDEBUG
+ printf("tcp_input: no more socket for inp=%x\n", inp);
+#endif
+ goto dropnosock;
+ }
+ tcp_lock(so, 1, 2);
+ if (in_pcb_checkstate(inp, WNT_RELEASE, 1) == WNT_STOPUSING) {
+ tcp_unlock(so, 1, 2);
+ inp = NULL; // pretend we didn't find it
+ goto dropnosock;
}
+
tp = intotcpcb(inp);
if (tp == 0) {
rstreason = BANDLIM_RST_CLOSEDPORT;
else
tiwin = th->th_win;
- so = inp->inp_socket;
if (so->so_options & (SO_DEBUG|SO_ACCEPTCONN)) {
#if TCPDEBUG
if (so->so_options & SO_DEBUG) {
}
#endif
if (so->so_options & SO_ACCEPTCONN) {
- register struct tcpcb *tp0 = tp;
+ register struct tcpcb *tp0 = tp;
struct socket *so2;
-#if IPSEC
struct socket *oso;
-#endif
+ struct sockaddr_storage from;
#if INET6
struct inpcb *oinp = sotoinpcb(so);
#endif /* INET6 */
+ int ogencnt = so->so_gencnt;
#if !IPSEC
/*
}
}
#endif
-
- so2 = sonewconn(so, 0);
+ if (so->so_filt) {
+ if (isipv6) {
+ struct sockaddr_in6 *sin6 = (struct sockaddr_in6*)&from;
+
+ sin6->sin6_len = sizeof(*sin6);
+ sin6->sin6_family = AF_INET6;
+ sin6->sin6_port = th->th_sport;
+ sin6->sin6_flowinfo = 0;
+ sin6->sin6_addr = ip6->ip6_src;
+ sin6->sin6_scope_id = 0;
+ } else {
+ struct sockaddr_in *sin = (struct sockaddr_in*)&from;
+
+ sin->sin_len = sizeof(*sin);
+ sin->sin_family = AF_INET;
+ sin->sin_port = th->th_sport;
+ sin->sin_addr = ip->ip_src;
+ }
+ so2 = sonewconn(so, 0, (struct sockaddr*)&from);
+ } else {
+ so2 = sonewconn(so, 0, NULL);
+ }
if (so2 == 0) {
tcpstat.tcps_listendrop++;
- so2 = sodropablereq(so);
- if (so2) {
- if (tcp_lq_overflow)
- sototcpcb(so2)->t_flags |=
- TF_LQ_OVERFLOW;
- tcp_drop(sototcpcb(so2), ETIMEDOUT);
- so2 = sonewconn(so, 0);
+ if (tcpdropdropablreq(so)) {
+ if (so->so_filt)
+ so2 = sonewconn(so, 0, (struct sockaddr*)&from);
+ else
+ so2 = sonewconn(so, 0, NULL);
}
- if (!so2)
+ if (!so2)
goto drop;
}
-#if IPSEC
+ /*
+ * Make sure listening socket did not get closed during socket allocation,
+ * not only this is incorrect but it is know to cause panic
+ */
+ if (so->so_gencnt != ogencnt)
+ goto drop;
+
oso = so;
-#endif
+ tcp_unlock(so, 0, 0); /* Unlock but keep a reference on listener for now */
+
so = so2;
+ tcp_lock(so, 1, 0);
/*
* This is ugly, but ....
*
}
#endif /* INET6 */
inp->inp_lport = th->th_dport;
- if (in_pcbinshash(inp) != 0) {
+ if (in_pcbinshash(inp, 0) != 0) {
/*
* Undo the assignments above if we failed to
* put the PCB on the hash lists.
#endif /* INET6 */
inp->inp_laddr.s_addr = INADDR_ANY;
inp->inp_lport = 0;
+ tcp_lock(oso, 0, 0); /* release ref on parent */
+ tcp_unlock(oso, 1, 0);
goto drop;
}
#if IPSEC
* Note: dropwithreset makes sure we don't
* send a RST in response to a RST.
*/
+ tcp_lock(oso, 0, 0); /* release ref on parent */
+ tcp_unlock(oso, 1, 0);
if (thflags & TH_ACK) {
tcpstat.tcps_badsyn++;
rstreason = BANDLIM_RST_OPENPORT;
} else
#endif /* INET6 */
inp->inp_options = ip_srcroute();
+ tcp_lock(oso, 0, 0);
#if IPSEC
/* copy old policy into new socket's */
if (sotoinpcb(oso)->inp_sp)
{
int error = 0;
+ lck_mtx_lock(sadb_mutex);
/* Is it a security hole here to silently fail to copy the policy? */
if (inp->inp_sp != NULL)
error = ipsec_init_policy(so, &inp->inp_sp);
if (error != 0 || ipsec_copy_policy(sotoinpcb(oso)->inp_sp, inp->inp_sp))
printf("tcp_input: could not copy policy\n");
+ lck_mtx_unlock(sadb_mutex);
}
#endif
+ tcp_unlock(oso, 1, 0); /* now drop the reference on the listener */
tp = intotcpcb(inp);
tp->t_state = TCPS_LISTEN;
tp->t_flags |= tp0->t_flags & (TF_NOPUSH|TF_NOOPT|TF_NODELAY);
-
+ tp->t_inpcb->inp_ip_ttl = tp0->t_inpcb->inp_ip_ttl;
/* Compute proper scaling value from buffer space */
while (tp->request_r_scale < TCP_MAX_WINSHIFT &&
TCP_MAXWIN << tp->request_r_scale <
}
}
+#if 1
+ lck_mtx_assert(((struct inpcb *)so->so_pcb)->inpcb_mtx, LCK_MTX_ASSERT_OWNED);
+#endif
+ /*
+ * Radar 3529618
+ * This is the second part of the MSS DoS prevention code (after
+ * minmss on the sending side) and it deals with too many too small
+ * tcp packets in a too short timeframe (1 second).
+ *
+ * For every full second we count the number of received packets
+ * and bytes. If we get a lot of packets per second for this connection
+ * (tcp_minmssoverload) we take a closer look at it and compute the
+ * average packet size for the past second. If that is less than
+ * tcp_minmss we get too many packets with very small payload which
+ * is not good and burdens our system (and every packet generates
+ * a wakeup to the process connected to our socket). We can reasonable
+ * expect this to be small packet DoS attack to exhaust our CPU
+ * cycles.
+ *
+ * Care has to be taken for the minimum packet overload value. This
+ * value defines the minimum number of packets per second before we
+ * start to worry. This must not be too low to avoid killing for
+ * example interactive connections with many small packets like
+ * telnet or SSH.
+ *
+ *
+ * Account for packet if payload packet, skip over ACK, etc.
+ *
+ * The packet per second count is done all the time and is also used
+ * by "DELAY_ACK" to detect streaming situations.
+ *
+ */
+ if (tp->t_state == TCPS_ESTABLISHED && tlen > 0) {
+ if (tp->rcv_reset > tcp_now) {
+ tp->rcv_pps++;
+ tp->rcv_byps += tlen + off;
+ /*
+ * Setting either tcp_minmssoverload or tcp_minmss to "0" disables
+ * the check.
+ */
+ if (tcp_minmss && tcp_minmssoverload && tp->rcv_pps > tcp_minmssoverload) {
+ if ((tp->rcv_byps / tp->rcv_pps) < tcp_minmss) {
+ char ipstrbuf[MAX_IPv6_STR_LEN];
+ printf("too many small tcp packets from "
+ "%s:%u, av. %lubyte/packet, "
+ "dropping connection\n",
+#ifdef INET6
+ isipv6 ?
+ inet_ntop(AF_INET6, &inp->in6p_faddr, ipstrbuf,
+ sizeof(ipstrbuf)) :
+#endif
+ inet_ntop(AF_INET, &inp->inp_faddr, ipstrbuf,
+ sizeof(ipstrbuf)),
+ inp->inp_fport,
+ tp->rcv_byps / tp->rcv_pps);
+ tp = tcp_drop(tp, ECONNRESET);
+/* tcpstat.tcps_minmssdrops++; */
+ goto drop;
+ }
+ }
+ } else {
+ tp->rcv_reset = tcp_now + PR_SLOWHZ;
+ tp->rcv_pps = 1;
+ tp->rcv_byps = tlen + off;
+ }
+ }
+
/*
* Segment received on connection.
* Reset idle time and keep-alive timer.
*/
tp->t_rcvtime = 0;
if (TCPS_HAVEESTABLISHED(tp->t_state))
- tp->t_timer[TCPT_KEEP] = tcp_keepidle;
+ tp->t_timer[TCPT_KEEP] = TCP_KEEPIDLE(tp);
/*
* Process options if not in LISTEN state,
else if (tp->t_timer[TCPT_PERSIST] == 0)
tp->t_timer[TCPT_REXMT] = tp->t_rxtcur;
- if (so->so_snd.sb_cc)
+ sowwakeup(so); /* has to be done with socket lock held */
+ if ((so->so_snd.sb_cc) || (tp->t_flags & TF_ACKNOW))
(void) tcp_output(tp);
- sowwakeup(so);
+ tcp_unlock(so, 1, 0);
KERNEL_DEBUG(DBG_FNC_TCP_INPUT | DBG_FUNC_END,0,0,0,0,0);
return;
}
* Add data to socket buffer.
*/
m_adj(m, drop_hdrlen); /* delayed header drop */
- sbappend(&so->so_rcv, m);
+ if (sbappend(&so->so_rcv, m))
+ sorwakeup(so);
#if INET6
if (isipv6) {
KERNEL_DEBUG(DBG_LAYER_END, ((th->th_dport << 16) | th->th_sport),
(((ip->ip_src.s_addr & 0xffff) << 16) | (ip->ip_dst.s_addr & 0xffff)),
th->th_seq, th->th_ack, th->th_win);
}
- if (tcp_delack_enabled) {
- TCP_DELACK_BITSET(tp->t_inpcb->hash_element);
+ if (DELAY_ACK(tp)) {
tp->t_flags |= TF_DELACK;
} else {
tp->t_flags |= TF_ACKNOW;
tcp_output(tp);
}
- sorwakeup(so);
+ tcp_unlock(so, 1, 0);
KERNEL_DEBUG(DBG_FNC_TCP_INPUT | DBG_FUNC_END,0,0,0,0,0);
return;
}
* Receive window is amount of space in rcv queue,
* but not less than advertised window.
*/
+#if 1
+ lck_mtx_assert(((struct inpcb *)so->so_pcb)->inpcb_mtx, LCK_MTX_ASSERT_OWNED);
+#endif
{ int win;
win = sbspace(&so->so_rcv);
register struct sockaddr_in6 *sin6;
#endif
- if (thflags & TH_RST)
+#if 1
+ lck_mtx_assert(((struct inpcb *)so->so_pcb)->inpcb_mtx, LCK_MTX_ASSERT_OWNED);
+#endif
+ if (thflags & TH_RST)
goto drop;
if (thflags & TH_ACK) {
rstreason = BANDLIM_RST_OPENPORT;
} else
#endif
{
+#if 1
+ lck_mtx_assert(((struct inpcb *)so->so_pcb)->inpcb_mtx, LCK_MTX_ASSERT_OWNED);
+#endif
MALLOC(sin, struct sockaddr_in *, sizeof *sin, M_SONAME,
M_NOWAIT);
if (sin == NULL)
* segment. Otherwise must send ACK now in case
* the other side is slow starting.
*/
- if (tcp_delack_enabled && ((thflags & TH_FIN) ||
+ if (DELAY_ACK(tp) && ((thflags & TH_FIN) ||
(tlen != 0 &&
#if INET6
(isipv6 && in6_localaddr(&inp->in6p_faddr))
)
#endif /* INET6 */
))) {
- TCP_DELACK_BITSET(tp->t_inpcb->hash_element);
tp->t_flags |= (TF_DELACK | TF_NEEDSYN);
}
- else
+ else {
tp->t_flags |= (TF_ACKNOW | TF_NEEDSYN);
+ }
/*
* Limit the `virtual advertised window' to TCP_MAXWIN
* If there's data, delay ACK; if there's also a FIN
* ACKNOW will be turned on later.
*/
- if (tcp_delack_enabled && tlen != 0) {
- TCP_DELACK_BITSET(tp->t_inpcb->hash_element);
+ if (DELAY_ACK(tp) && tlen != 0) {
tp->t_flags |= TF_DELACK;
}
- else
+ else {
tp->t_flags |= TF_ACKNOW;
+ }
/*
* Received <SYN,ACK> in SYN_SENT[*] state.
* Transitions:
thflags &= ~TH_SYN;
} else {
tp->t_state = TCPS_ESTABLISHED;
- tp->t_timer[TCPT_KEEP] = tcp_keepidle;
+ tp->t_timer[TCPT_KEEP] = TCP_KEEPIDLE(tp);
}
} else {
/*
tp->t_flags &= ~TF_NEEDFIN;
} else {
tp->t_state = TCPS_ESTABLISHED;
- tp->t_timer[TCPT_KEEP] = tcp_keepidle;
+ tp->t_timer[TCPT_KEEP] = TCP_KEEPIDLE(tp);
}
tp->t_flags |= TF_NEEDSYN;
} else
}
if (CC_GT(to.to_cc, tp->cc_recv)) {
tp = tcp_close(tp);
+ tcp_unlock(so, 1, 50);
goto findpcb;
}
else
goto drop;
}
break; /* continue normal processing */
+
+ /* Received a SYN while connection is already established.
+ * This is a "half open connection and other anomalies" described
+ * in RFC793 page 34, send an ACK so the remote reset the connection
+ * or recovers by adjusting its sequence numberering
+ */
+ case TCPS_ESTABLISHED:
+ if (thflags & TH_SYN)
+ goto dropafterack;
+ break;
}
/*
goto drop;
}
+#if 1
+ lck_mtx_assert(((struct inpcb *)so->so_pcb)->inpcb_mtx, LCK_MTX_ASSERT_OWNED);
+#endif
/*
* RFC 1323 PAWS: If we have a timestamp reply on this segment
* and it's less than ts_recent, drop it.
SEQ_GT(th->th_seq, tp->rcv_nxt)) {
iss = tcp_new_isn(tp);
tp = tcp_close(tp);
+ tcp_unlock(so, 1, 0);
goto findpcb;
}
/*
tp->t_flags &= ~TF_NEEDFIN;
} else {
tp->t_state = TCPS_ESTABLISHED;
- tp->t_timer[TCPT_KEEP] = tcp_keepidle;
+ tp->t_timer[TCPT_KEEP] = TCP_KEEPIDLE(tp);
}
/*
* If segment contains data or ACK, will call tcp_reass()
tp->snd_wnd -= acked;
ourfinisacked = 0;
}
+ sowwakeup(so);
+ /* detect una wraparound */
+ if (SEQ_GEQ(tp->snd_una, tp->snd_recover) &&
+ SEQ_LT(th->th_ack, tp->snd_recover))
+ tp->snd_recover = th->th_ack;
+ if (SEQ_GT(tp->snd_una, tp->snd_high) &&
+ SEQ_LEQ(th->th_ack, tp->snd_high))
+ tp->snd_high = th->th_ack - 1;
tp->snd_una = th->th_ack;
if (SEQ_LT(tp->snd_nxt, tp->snd_una))
tp->snd_nxt = tp->snd_una;
- sowwakeup(so);
switch (tp->t_state) {
}
add_to_time_wait(tp);
tp->t_state = TCPS_FIN_WAIT_2;
+ goto drop;
}
break;
if (th->th_seq == tp->rcv_nxt &&
LIST_EMPTY(&tp->t_segq) &&
TCPS_HAVEESTABLISHED(tp->t_state)) {
-#ifdef __APPLE__
- if (tcp_delack_enabled) {
- TCP_DELACK_BITSET(tp->t_inpcb->hash_element);
+ if (DELAY_ACK(tp) && ((tp->t_flags & TF_ACKNOW) == 0)) {
tp->t_flags |= TF_DELACK;
}
-#else
- if (DELAY_ACK(tp))
- callout_reset(tp->tt_delack, tcp_delacktime,
- tcp_timer_delack, tp);
-#endif
- else
+ else {
tp->t_flags |= TF_ACKNOW;
+ }
tp->rcv_nxt += tlen;
thflags = th->th_flags & TH_FIN;
tcpstat.tcps_rcvpack++;
tcpstat.tcps_rcvbyte += tlen;
ND6_HINT(tp);
- sbappend(&so->so_rcv, m);
- sorwakeup(so);
+ if (sbappend(&so->so_rcv, m))
+ sorwakeup(so);
} else {
thflags = tcp_reass(tp, th, &tlen, m);
tp->t_flags |= TF_ACKNOW;
* Otherwise, since we received a FIN then no
* more input can be expected, send ACK now.
*/
- if (tcp_delack_enabled && (tp->t_flags & TF_NEEDSYN)) {
- TCP_DELACK_BITSET(tp->t_inpcb->hash_element);
+ if (DELAY_ACK(tp) && (tp->t_flags & TF_NEEDSYN)) {
tp->t_flags |= TF_DELACK;
}
- else
+ else {
tp->t_flags |= TF_ACKNOW;
+ }
tp->rcv_nxt++;
}
switch (tp->t_state) {
*/
if (needoutput || (tp->t_flags & TF_ACKNOW))
(void) tcp_output(tp);
+ tcp_unlock(so, 1, 0);
KERNEL_DEBUG(DBG_FNC_TCP_INPUT | DBG_FUNC_END,0,0,0,0,0);
return;
m_freem(m);
tp->t_flags |= TF_ACKNOW;
(void) tcp_output(tp);
+ tcp_unlock(so, 1, 0);
KERNEL_DEBUG(DBG_FNC_TCP_INPUT | DBG_FUNC_END,0,0,0,0,0);
return;
-
+dropwithresetnosock:
+ nosock = 1;
dropwithreset:
/*
* Generate a RST, dropping incoming segment.
(tcp_seq)0, TH_RST|TH_ACK);
}
/* destroy temporarily created socket */
- if (dropsocket)
- (void) soabort(so);
+ if (dropsocket) {
+ (void) soabort(so);
+ tcp_unlock(so, 1, 0);
+ }
+ else
+ if ((inp != NULL) && (nosock == 0))
+ tcp_unlock(so, 1, 0);
KERNEL_DEBUG(DBG_FNC_TCP_INPUT | DBG_FUNC_END,0,0,0,0,0);
return;
-
+dropnosock:
+ nosock = 1;
drop:
/*
* Drop space held by incoming segment and return.
#endif
m_freem(m);
/* destroy temporarily created socket */
- if (dropsocket)
- (void) soabort(so);
+ if (dropsocket) {
+ (void) soabort(so);
+ tcp_unlock(so, 1, 0);
+ }
+ else
+ if (nosock == 0)
+ tcp_unlock(so, 1, 0);
KERNEL_DEBUG(DBG_FNC_TCP_INPUT | DBG_FUNC_END,0,0,0,0,0);
return;
}
isipv6 ? tcp_v6mssdflt :
#endif /* INET6 */
tcp_mssdflt;
- else
+ else {
+ /*
+ * Prevent DoS attack with too small MSS. Round up
+ * to at least minmss.
+ */
+ offer = max(offer, tcp_minmss);
/*
* Sanity check: make sure that maxopd will be large
* enough to allow some data on segments even is the
* funny things may happen in tcp_output.
*/
offer = max(offer, 64);
+ }
taop->tao_mssopt = offer;
/*
(tp->t_flags & TF_RCVD_CC) == TF_RCVD_CC))
mss -= TCPOLEN_CC_APPA;
-#if (MCLBYTES & (MCLBYTES - 1)) == 0
- if (mss > MCLBYTES)
- mss &= ~(MCLBYTES-1);
-#else
- if (mss > MCLBYTES)
- mss = mss / MCLBYTES * MCLBYTES;
-#endif
/*
- * If there's a pipesize, change the socket buffer
- * to that size. Make the socket buffers an integral
+ * If there's a pipesize (ie loopback), change the socket
+ * buffer to that size only if it's bigger than the current
+ * sockbuf size. Make the socket buffers an integral
* number of mss units; if the mss is larger than
* the socket buffer, decrease the mss.
*/
#if RTV_SPIPE
- if ((bufsize = rt->rt_rmx.rmx_sendpipe) == 0)
+ bufsize = rt->rt_rmx.rmx_sendpipe;
+ if (bufsize < so->so_snd.sb_hiwat)
#endif
bufsize = so->so_snd.sb_hiwat;
if (bufsize < mss)
tp->t_maxseg = mss;
#if RTV_RPIPE
- if ((bufsize = rt->rt_rmx.rmx_recvpipe) == 0)
+ bufsize = rt->rt_rmx.rmx_recvpipe;
+ if (bufsize < so->so_rcv.sb_hiwat)
#endif
bufsize = so->so_rcv.sb_hiwat;
if (bufsize > mss) {
* is called)
*/
tp->snd_cwnd = tp->t_maxseg + (th->th_ack - tp->snd_una);
+ tp->t_flags |= TF_ACKNOW;
(void) tcp_output(tp);
tp->snd_cwnd = ocwnd;
if (SEQ_GT(onxt, tp->snd_nxt))
}
return (0);
}
+
+/*
+ * Drop a random TCP connection that hasn't been serviced yet and
+ * is eligible for discard. There is a one in qlen chance that
+ * we will return a null, saying that there are no dropable
+ * requests. In this case, the protocol specific code should drop
+ * the new request. This insures fairness.
+ *
+ * The listening TCP socket "head" must be locked
+ */
+static int
+tcpdropdropablreq(struct socket *head)
+{
+ struct socket *so;
+ unsigned int i, j, qlen;
+ static int rnd;
+ static struct timeval old_runtime;
+ static unsigned int cur_cnt, old_cnt;
+ struct timeval tv;
+ struct inpcb *inp = NULL;
+ struct tcpcb *tp;
+
+ microtime(&tv);
+ if ((i = (tv.tv_sec - old_runtime.tv_sec)) != 0) {
+ old_runtime = tv;
+ old_cnt = cur_cnt / i;
+ cur_cnt = 0;
+ }
+
+ so = TAILQ_FIRST(&head->so_incomp);
+ if (!so)
+ return 0;
+
+ qlen = head->so_incqlen;
+ if (++cur_cnt > qlen || old_cnt > qlen) {
+ rnd = (314159 * rnd + 66329) & 0xffff;
+ j = ((qlen + 1) * rnd) >> 16;
+
+ while (j-- && so)
+ so = TAILQ_NEXT(so, so_list);
+ }
+ /* Find a connection that is not already closing */
+ while (so) {
+ inp = (struct inpcb *)so->so_pcb;
+
+ if (in_pcb_checkstate(inp, WNT_ACQUIRE, 0) != WNT_STOPUSING)
+ break;
+
+ so = TAILQ_NEXT(so, so_list);
+ }
+ if (!so)
+ return 0;
+
+ head->so_incqlen--;
+ head->so_qlen--;
+ TAILQ_REMOVE(&head->so_incomp, so, so_list);
+ tcp_unlock(head, 0, 0);
+
+ /* Let's remove this connection from the incomplete list */
+ tcp_lock(so, 1, 0);
+
+ if (in_pcb_checkstate(inp, WNT_RELEASE, 1) == WNT_STOPUSING) {
+ tcp_unlock(so, 1, 0);
+ return 0;
+ }
+
+ so->so_head = NULL;
+ so->so_usecount--; /* No more held by so_head */
+
+ /*
+ * We do not want to lose track of the PCB right away in case we receive
+ * more segments from the peer
+ */
+ tp = sototcpcb(so);
+ tp->t_flags |= TF_LQ_OVERFLOW;
+ tp->t_state = TCPS_CLOSED;
+ (void) tcp_output(tp);
+ tcpstat.tcps_drops++;
+ soisdisconnected(so);
+ tcp_canceltimers(tp);
+ add_to_time_wait(tp);
+
+ tcp_unlock(so, 1, 0);
+ tcp_lock(head, 0, 0);
+
+ return 1;
+
+}
+
+
projects / apple / xnu.git / blobdiff