tcp_input.c revision 721fffe35d40e548a5a58dc53a2ec9c6762172d9
/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License (the "License").
* You may not use this file except in compliance with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
* Copyright 2010 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
/* This file contains all TCP input processing functions. */
#define _SUN_TPI_VERSION 2
#include <sys/xti_inet.h>
#include <sys/squeue_impl.h>
#include <inet/tcp_impl.h>
#include <inet/tcp_cluster.h>
#include <inet/proto_set.h>
#include <inet/ipsec_impl.h>
/*
* RFC1323-recommended phrasing of TSTAMP option, for easier parsing
*/
#ifdef _BIG_ENDIAN
#else
#endif
/*
* Flags returned from tcp_parse_options.
*/
#define TCP_OPT_MSS_PRESENT 1
#define TCP_OPT_WSCALE_PRESENT 2
#define TCP_OPT_TSTAMP_PRESENT 4
#define TCP_OPT_SACK_OK_PRESENT 8
#define TCP_OPT_SACK_PRESENT 16
/*
* PAWS needs a timer for 24 days. This is the number of ticks in 24 days
*/
/*
* Since tcp_listener is not cleared atomically with tcp_detached
* being cleared we need this extra bit to tell a detached connection
* apart from one that is in the process of being accepted.
*/
#define TCP_IS_DETACHED_NONEAGER(tcp) \
(TCP_IS_DETACHED(tcp) && \
(!(tcp)->tcp_hard_binding))
/*
* Steps to do when a tcp_t moves to TIME-WAIT state.
*
* This connection is done, we don't need to account for it. Decrement
* the listener connection counter if needed.
*
* Decrement the connection counter of the stack. Note that this counter
* is per CPU. So the total number of connections in a stack is the sum of all
* of them. Since there is no lock for handling all of them exclusively, the
* resulting sum is only an approximation.
*
* Unconditionally clear the exclusive binding bit so this TIME-WAIT
* connection won't interfere with new ones.
*
* Start the TIME-WAIT timer. If upper layer has not closed the connection,
* the timer is handled within the context of this tcp_t. When the timer
* fires, tcp_clean_death() is called. If upper layer closes the connection
* during this period, tcp_time_wait_append() will be called to add this
* tcp_t to the global TIME-WAIT list. Note that this means that the
* actual wait time in TIME-WAIT state will be longer than the
* tcps_time_wait_interval since the period before upper layer closes the
* connection is not accounted for when tcp_time_wait_append() is called.
*
* If uppser layer has closed the connection, call tcp_time_wait_append()
* directly.
*
*/
{ \
(connp)->conn_exclbind = 0; \
if (!TCP_IS_DETACHED(tcp)) { \
} else { \
} \
}
/*
* If tcp_drop_ack_unsent_cnt is greater than 0, when TCP receives more
* than tcp_drop_ack_unsent_cnt number of ACKs which acknowledge unsent
* data, TCP will not respond with an ACK. RFC 793 requires that
* TCP responds with an ACK for such a bogus ACK. By not following
* the RFC, we prevent TCP from getting into an ACK storm if somehow
* an attacker successfully spoofs an acceptable segment to our
* peer; or when our peer is "confused."
*/
/*
* The shift factor applied to tcp_mss to decide if the peer sends us a
* valid initial receive window. By default, if the peer receive window
* is smaller than 1 MSS (shift factor is 0), it is considered as invalid.
*/
static uint32_t tcp_init_wnd_shft = 0;
/* Process ICMP source quench message or not. */
ip_recv_attr_t *);
ip_recv_attr_t *);
ip_recv_attr_t *);
/*
* Set the MSS associated with a particular tcp based on its current value,
* and a new one passed in. Observe minimums and maximums, and reset other
* state variables that we want to view as multiples of MSS.
*
* The value of MSS could be either increased or descreased.
*/
void
{
else
/*
* Unless naglim has been set by our client to
* a non-mss value, force naglim to track mss.
* This can help to aggregate small writes.
*/
/*
* TCP should be able to buffer at least 4 MSS data for obvious
* performance reason.
*/
/*
* Set the send lowater to at least twice of MSS.
*/
/*
* Update tcp_cwnd according to the new value of MSS. Keep the
* previous ratio to preserve the transmit rate.
*/
tcp->tcp_cwnd_cnt = 0;
}
/*
* Extract option values from a tcp header. We put any found values into the
* tcpopt struct and return a bitmask saying which options were found.
*/
static int
{
int len;
int found = 0;
switch (*up) {
case TCPOPT_EOL:
break;
case TCPOPT_NOP:
up++;
continue;
case TCPOPT_MAXSEG:
if (len < TCPOPT_MAXSEG_LEN ||
break;
/* Caller must handle tcp_mss_min and tcp_mss_max_* */
up += TCPOPT_MAXSEG_LEN;
continue;
case TCPOPT_WSCALE:
break;
else
up += TCPOPT_WS_LEN;
continue;
case TCPOPT_SACK_PERMITTED:
if (len < TCPOPT_SACK_OK_LEN ||
break;
up += TCPOPT_SACK_OK_LEN;
continue;
case TCPOPT_SACK:
break;
/* If TCP is not interested in SACK blks... */
continue;
}
up += TCPOPT_HEADER_LEN;
/*
* If the list is empty, allocate one and assume
* nothing is sack'ed.
*/
&(tcp->tcp_num_notsack_blk),
&(tcp->tcp_cnt_notsack_list));
/*
* Make sure tcp_notsack_list is not NULL.
* This happens when kmem_alloc(KM_NOSLEEP)
* returns NULL.
*/
continue;
}
}
while (sack_len > 0) {
break;
}
up += 4;
up += 4;
sack_len -= 8;
/*
* Bounds checking. Make sure the SACK
* info is within tcp_suna and tcp_snxt.
* If this SACK blk is out of bound, ignore
* it but continue to parse the following
* blks.
*/
continue;
}
&(tcp->tcp_num_notsack_blk),
&(tcp->tcp_cnt_notsack_list));
}
}
continue;
case TCPOPT_TSTAMP:
if (len < TCPOPT_TSTAMP_LEN ||
break;
up += TCPOPT_TSTAMP_LEN;
continue;
default:
break;
continue;
}
break;
}
return (found);
}
/*
* Process all TCP option in SYN segment. Note that this function should
* be called after tcp_set_destination() is called so that the necessary info
* from IRE is already set in the tcp structure.
*
* This function sets up the correct tcp_mss value according to the
* MSS option value and our header size. It also sets up the window scale
* and timestamp values, and initialize SACK info blocks. But it does not
* change receive window size after setting the tcp_mss value. The caller
* should do the appropriate change.
*/
static void
{
int options;
char *tmp_tcph;
/*
* Process MSS option. Note that MSS option value does not account
* for IP or TCP options. This means that it is equal to MTU - minimum
* IP+TCP header size, which is 40 bytes for IPv4 and 60 bytes for
* IPv6.
*/
if (!(options & TCP_OPT_MSS_PRESENT)) {
else
} else {
else
}
/* Process Window Scale option. */
if (options & TCP_OPT_WSCALE_PRESENT) {
} else {
}
/* Process Timestamp option. */
if ((options & TCP_OPT_TSTAMP_PRESENT) &&
/* Fill in our template header with basic timestamp option. */
tmp_tcph[0] = TCPOPT_NOP;
} else {
}
/*
* Process SACK options. If SACK is enabled for this connection,
* then allocate the SACK info structure. Note the following ways
* when tcp_snd_sack_ok is set to true.
*
* For active connection: in tcp_set_destination() called in
* tcp_connect().
*
* For passive connection: in tcp_set_destination() called in
* tcp_input_listener().
*
* That's the reason why the extra TCP_IS_DETACHED() check is there.
* That check makes sure that if we did not send a SACK OK option,
* we will not enable SACK for this connection even though the other
* side sends us SACK OK option. For active connection, the SACK
* info structure has already been allocated. So we need to free
* it if SACK is disabled.
*/
if ((options & TCP_OPT_SACK_OK_PRESENT) &&
(tcp->tcp_snd_sack_ok ||
/* This should be true only in the passive case. */
tcp->tcp_sack_info =
}
} else {
if (tcp->tcp_snd_ts_ok) {
} else {
}
}
} else {
/*
* Resetting tcp_snd_sack_ok to B_FALSE so that
* no SACK info will be used for this
* connection. This assumes that SACK usage
* permission is negotiated. This may need
* to be changed once this is clarified.
*/
tcp->tcp_sack_info);
}
}
/*
* that from tcp_mss to get our side's MSS.
*/
/*
* Here we assume that the other side's header size will be equal to
* our header size. We calculate the real MSS accordingly. Need to
* take into additional stuffs IPsec puts in.
*
*/
/*
* Set MSS to the smaller one of both ends of the connection.
* We should not have called tcp_mss_set() before, but our
* side of the MSS should have been set to a proper value
* by tcp_set_destination(). tcp_mss_set() will also set up the
* STREAM head parameters properly.
*
* If we have a larger-than-16-bit window but the other side
* didn't want to do window scale, tcp_rwnd_set() will take
* care of that.
*/
/*
* Initialize tcp_cwnd value. After tcp_mss_set(), tcp_mss has been
* updated properly.
*/
}
/*
* Add a new piece to the tcp reassembly queue. If the gap at the beginning
* is filled, return as much as we can. The message passed in may be
* multi-part, chained using b_cont. "start" is the starting sequence
* number for this piece.
*/
static mblk_t *
{
/* Walk through all the new pieces. */
do {
/* Empty. Blast it. */
continue;
}
if (!mp1) {
continue;
}
/* New stuff completely beyond tail? */
/* Link it on end. */
continue;
}
/* New stuff at the front? */
/* Yes... Check for overlap. */
continue;
}
/*
* The new piece fits somewhere between the head and tail.
* We find our slot, where mp1 precedes us and mp2 trails.
*/
break;
}
/* Link ourselves in */
/* Trim overlap with following mblk(s) first */
/* Trim overlap with preceding mblk */
/* Anything ready to go? */
return (NULL);
/* Eat what we can off the queue */
for (;;) {
TCP_REASS_SET_SEQ(mp1, 0);
TCP_REASS_SET_END(mp1, 0);
if (!mp) {
break;
}
break;
}
}
return (mp1);
}
/* Eliminate any overlap that mp may have over later mblks */
static void
{
break;
break;
}
TCP_REASS_SET_SEQ(mp1, 0);
TCP_REASS_SET_END(mp1, 0);
}
if (!mp1)
}
/*
* This function does PAWS protection check. Returns B_TRUE if the
* segment passes the PAWS test, else returns B_FALSE.
*/
{
int options;
/*
* If timestamp option is aligned nicely, get values inline,
* otherwise call general routine to parse. Only do that
* if timestamp is the only option.
*/
} else {
if (tcp->tcp_snd_sack_ok) {
} else {
}
}
if (options & TCP_OPT_TSTAMP_PRESENT) {
/*
* Do PAWS per RFC 1323 section 4.2. Accept RST
* regardless of the timestamp, page 18 RFC 1323.bis.
*/
tcp->tcp_ts_recent)) {
if (TSTMP_LT(LBOLT_FASTPATH64,
/* This segment is not acceptable. */
return (B_FALSE);
} else {
/*
* Connection has been idle for
* too long. Reset the timestamp
* and assume the segment is valid.
*/
tcp->tcp_ts_recent =
}
}
} else {
/*
* If we don't get a timestamp on every packet, we
* figure we can't really trust 'em, so we stop sending
* and parsing them.
*/
/*
* Adjust the tcp_mss and tcp_cwnd accordingly. We avoid
* doing a slow start here so as to not to lose on the
* transfer rate built up so far.
*/
if (tcp->tcp_snd_sack_ok) {
}
}
return (B_TRUE);
}
/*
* Defense for the SYN attack -
* 1. When q0 is full, drop from the tail (tcp_eager_prev_drop_q0) the oldest
* one from the list of droppable eagers. This list is a subset of q0.
* see comments before the definition of MAKE_DROPPABLE().
* 2. Don't drop a SYN request before its first timeout. This gives every
* request at least til the first timeout to complete its 3-way handshake.
* 3. Maintain tcp_syn_rcvd_timeout as an accurate count of how many
* requests currently on the queue that has timed out. This will be used
* as an indicator of whether an attack is under way, so that appropriate
* actions can be taken. (It's incremented in tcp_timer() and decremented
* either when eager goes into ESTABLISHED, or gets freed up.)
* 4. The current threshold is - # of timeout > q0len/4 => SYN alert on
* # of timeout drops back to <= q0len/32 => SYN alert off
*/
static boolean_t
{
/* Pick oldest eager from the list of droppable eagers */
/* If list is empty. return B_FALSE */
return (B_FALSE);
}
/* If allocated, the mp will be freed in tcp_clean_death_wrapper() */
return (B_FALSE);
/*
* Take this eager out from the list of droppable eagers since we are
* going to drop it.
*/
"tcp_drop_q0: listen half-open queue (max=%d) overflow"
}
/* Put a reference on the conn as we are enqueueing it in the sqeue */
return (B_TRUE);
}
/*
* Handle a SYN on an AF_INET6 socket; can be either IPv4 or IPv6
*/
static mblk_t *
{
(char *)&tcp,
(t_scalar_t)sizeof (intptr_t),
} else {
}
} else {
/* Pass up the scope_id of remote addr */
} else {
sin6.sin6_scope_id = 0;
}
} else {
}
}
return (tpi_mp);
}
/* Handle a SYN on an AF_INET socket */
static mblk_t *
{
} else {
}
return (tpi_mp);
}
/*
* Called via squeue to get on to eager's perimeter. It sends a
* TH_RST if eager is in the fanout table. The listener wants the
* eager to disappear either by means of tcp_eager_blowoff() or
* tcp_eager_cleanup() being called. tcp_eager_kill() can also be
* called (via squeue) if the eager cannot be inserted in the
* fanout table in tcp_input_listener().
*/
/* ARGSUSED */
void
{
/*
* We could be called because listener is closing. Since
* the eager was using listener's queue's, we avoid
* using the listeners queues from now on.
*/
/*
* An eager's conn_fanout will be NULL if it's a duplicate
* for an existing 4-tuples in the conn fanout table.
* We don't want to send an RST out in such case.
*/
tcp_xmit_ctl("tcp_eager_kill, can't wait",
}
/* We are here because listener wants this eager gone */
if (eager->tcp_tconnind_started) {
/*
* The eager has sent a conn_ind up to the
* listener but listener decides to close
* instead. We need to drop the extra ref
* placed on eager in tcp_input_data() before
* sending the conn_ind to listener.
*/
}
}
}
/*
* Reset any eager connection hanging off this listener marked
* with 'seqnum' and then reclaim it's resources.
*/
{
do {
return (B_FALSE);
}
if (eager->tcp_closemp_used) {
return (B_TRUE);
}
return (B_TRUE);
}
/*
* Reset any eager connection hanging off this listener
* and then reclaim it's resources.
*/
void
{
if (!q0_only) {
/* First cleanup q */
if (!eager->tcp_closemp_used) {
}
}
}
/* Then cleanup q0 */
if (!eager->tcp_closemp_used) {
}
}
}
/*
* If we are an eager connection hanging off a listener that hasn't
* formally accepted the connection yet, get off his list and blow off
* any data that we have accumulated.
*/
void
{
/* Remove the eager tcp from q0 */
/*
* Take the eager out, if it is in the list of droppable
* eagers.
*/
if (tcp->tcp_syn_rcvd_timeout != 0) {
/* we have timed out before */
}
} else {
/*
* If we are unlinking the last
* element on the list, adjust
* tail pointer. Set tail pointer
* to nil when list is empty.
*/
if (listener->tcp_eager_last_q ==
NULL;
} else {
/*
* We won't get here if there
* is only one eager in the
* list.
*/
prev;
}
}
break;
}
}
}
}
/* BEGIN CSTYLED */
/*
*
* The sockfs ACCEPT path:
* =======================
*
* The eager is now established in its own perimeter as soon as SYN is
* received in tcp_input_listener(). When sockfs receives conn_ind, it
* completes the accept processing on the acceptor STREAM. The sending
* on the listener perimeter.
*
* Common control flow for 3 way handshake:
* ----------------------------------------
*
* incoming SYN (listener perimeter) -> tcp_input_listener()
*
* incoming SYN-ACK-ACK (eager perim) -> tcp_input_data()
* send T_CONN_IND (listener perim) -> tcp_send_conn_ind()
*
* Sockfs ACCEPT Path:
* -------------------
*
* open acceptor stream (tcp_open allocates tcp_tli_accept()
* as STREAM entry point)
*
* soaccept() sends T_CONN_RES on the acceptor STREAM to tcp_tli_accept()
*
* tcp_tli_accept() extracts the eager and makes the q->q_ptr <-> eager
* association (we are not behind eager's squeue but sockfs is protecting us
* and no one knows about this stream yet. The STREAMS entry point q->q_info
* is changed to point at tcp_wput().
*
* tcp_accept_common() sends any deferred eagers via tcp_send_pending() to
* listener (done on listener's perimeter).
*
* tcp_tli_accept() calls tcp_accept_finish() on eagers perimeter to finish
* accept.
*
* ---------------------------
*
* soaccept() sends T_CONN_RES on the listener STREAM.
*
* tcp_tli_accept() -> tcp_accept_swap() complete the processing and send
* a M_SETOPS mblk to eager perimeter to finish accept (tcp_accept_finish()).
*
* Locks:
* ======
*
* listener->tcp_eager_lock protects the listeners->tcp_eager_next_q0 and
* and listeners->tcp_eager_next_q.
*
* Referencing:
* ============
*
* 1) We start out in tcp_input_listener by eager placing a ref on
* listener and listener adding eager to listeners->tcp_eager_next_q0.
*
* 2) When a SYN-ACK-ACK arrives, we send the conn_ind to listener. Before
* doing so we place a ref on the eager. This ref is finally dropped at the
* end of tcp_accept_finish() while unwinding from the squeue, i.e. the
* reference is dropped by the squeue framework.
*
* 3) The ref on listener placed in 1 above is dropped in tcp_accept_finish
*
* The reference must be released by the same entity that added the reference
* In the above scheme, the eager is the entity that adds and releases the
* references. Note that tcp_accept_finish executes in the squeue of the eager
* (albeit after it is attached to the acceptor stream). Though 1. executes
* in the listener's squeue, the eager is nascent at this point and the
* reference can be considered to have been added on behalf of the eager.
*
* Eager getting a Reset or listener closing:
* ==========================================
*
* Once the listener and eager are linked, the listener never does the unlink.
* If the listener needs to close, tcp_eager_cleanup() is called which queues
* a message on all eager perimeter. The eager then does the unlink, clears
* any pointers to the listener's queue and drops the reference to the
* listener. The listener waits in tcp_close outside the squeue until its
* refcount has dropped to 1. This ensures that the listener has waited for
* all eagers to clear their association with the listener.
*
* Similarly, if eager decides to go away, it can unlink itself and close.
* When the T_CONN_RES comes down, we check if eager has closed. Note that
* the reference to eager is still valid because of the extra ref we put
* in tcp_send_conn_ind.
*
* Listener can always locate the eager under the protection
* of the listener->tcp_eager_lock, and then do a refhold
* on the eager during the accept processing.
*
* The acceptor stream accesses the eager in the accept processing
* based on the ref placed on eager before sending T_conn_ind.
* The only entity that can negate this refhold is a listener close
* which is mutually exclusive with an active acceptor stream.
*
* Eager's reference on the listener
* ===================================
*
* If the accept happens (even on a closed eager) the eager drops its
* reference on the listener at the start of tcp_accept_finish. If the
* eager is killed due to an incoming RST before the T_conn_ind is sent up,
* the reference is dropped in tcp_closei_local. If the listener closes,
* the reference is dropped in tcp_eager_kill. In all cases the reference
* is dropped while executing in the eager's context (squeue).
*/
/* END CSTYLED */
/* Process the SYN packet, mp, directed at the listener 'tcp' */
/*
* THIS FUNCTION IS DIRECTLY CALLED BY IP VIA SQUEUE FOR SYN.
* tcp_input_data will not see any packets for listeners since the listener
* has conn_recv set to tcp_input_listener.
*/
/* ARGSUSED */
static void
{
int err;
return;
}
/* Note this executes in listener's squeue */
return;
}
return;
}
goto error2;
/*
* The system is under memory pressure, so we need to do our part
* to relieve the pressure. So we only accept new request if there
* is nothing waiting to be accepted or waiting to complete the 3-way
* handshake. This means that busy listener will not get too many
* new requests which they cannot handle in time while non-busy
* listener is still functioning properly.
*/
listener->tcp_conn_req_cnt_q0 > 0)) {
goto error2;
}
if (lconnp->conn_debug) {
"tcp_input_listener: listen backlog (max=%d) "
"overflow (%d pending) on %s",
}
goto error2;
}
if (listener->tcp_conn_req_cnt_q0 >=
/*
* Q0 is full. Drop a pending half-open req from the queue
* to make room for the new SYN req. Also mark the time we
* drop a SYN.
*
* A more aggressive defense against SYN attack will
* be to set the "tcp_syn_defense" flag now.
*/
if (!tcp_drop_q0(listener)) {
if (lconnp->conn_debug) {
"tcp_input_listener: listen half-open "
"queue (max=%d) full (%d pending) on %s",
}
goto error2;
}
}
/*
* Enforce the limit set on the number of connections per listener.
* Note that tlc_cnt starts with 1. So need to add 1 to tlc_max
* for comparison.
*/
now = ddi_get_lbolt64();
"Listener (port %d) connection max (%u) "
"reached: %u attempts dropped total\n",
}
goto error2;
}
}
/*
* IP sets ira_sqp to either the senders conn_sqp (for loopback)
* or based on the ring (for packets from GLD). Otherwise it is
* set based on lbolt i.e., a somewhat random number.
*/
goto error2;
if (err != 0)
goto error3;
/* We already know the laddr of the new connection is ours */
} else {
}
goto error3;
IXAF_VERIFY_PMTU | IXAF_VERIFY_LSO)) ==
if (!tcps->tcps_dev_flow_ctl)
/* Prepare for diffing against previous packets */
eager->tcp_recvifindex = 0;
}
}
/* Source routing option copyover (reverse it) */
if (err != 0) {
goto error3;
}
}
/*
* If the SYN came with a credential, it's a loopback packet or a
* labeled packet; attach the credential to the TPI message.
*/
/* Inherit the listener's SSL protection state */
}
/* Inherit the listener's non-STREAMS flag */
if (IPCL_IS_NONSTR(lconnp)) {
}
if (!IPCL_IS_NONSTR(econnp)) {
/*
* Pre-allocate the T_ordrel_ind mblk for TPI socket so that
* at close time, we will always have that to send up.
* Otherwise, we need to do special handling in case the
* allocation fails at that time.
*/
goto error3;
}
/*
* Now that the IP addresses and ports are setup in econnp we
* can do the IPsec policy work.
*/
/*
* Inherit the policy from the listener; use
* actions from ira
*/
goto error3;
}
}
}
/* Inherit various TCP parameters from the listener */
/*
* tcp_set_destination() may set tcp_rwnd according to the route
* metrics. If it does not, the eager's receive window will be set
* to the listener's receive window later in this function.
*/
/*
* Inherit listener's tcp_init_cwnd. Need to do this before
* calling tcp_process_options() which set the initial cwnd.
*/
if (is_system_labeled()) {
/* Discard any old label */
}
/*
* If this is an MLP connection or a MAC-Exempt
* connection with an unlabeled node, packets are to be
* exchanged using the security label of the received
* SYN packet instead of the server application's label.
* tsol_check_dest called from ip_set_destination
* might later update TSF_UNLABELED by replacing
* ixa_tsl with a new label.
*/
} else {
}
/*
* conn_connect() called from tcp_set_destination will verify
* the destination is allowed to receive packets at the
* security label of the SYN-ACK we are generating. As part of
* that, tsol_check_dest() may create a new effective label for
* this connection.
* Finally conn_connect() will call conn_update_label.
* All that remains for TCP to do is to call
* conn_build_hdr_template which is done as part of
* tcp_set_destination.
*/
}
/*
* Since we will clear tcp_listener before we clear tcp_detached
* in the accept code we need tcp_hard_binding aka tcp_accept_inprogress
* so we can tell a TCP_DETACHED_NONEAGER apart.
*/
if (err != 0) {
goto error3;
}
/*
* No need to check for multicast destination since ip will only pass
* up multicasts to those that have expressed interest
* TODO: what about rejecting broadcasts?
* Also check that source is not a multicast or broadcast address.
*/
/*
* Adapt our mss, ttl, ... based on the remote address.
*/
if (tcp_set_destination(eager) != 0) {
/* Undo the bind_hash_insert */
goto error3;
}
/* Process all TCP options. */
/* Is the other end ECN capable? */
}
/*
* The listener's conn_rcvbuf should be the default window size or a
* window size changed via SO_RCVBUF option. First round up the
* eager's tcp_rwnd to the nearest MSS. Then find out the window
* scale option value if needed. Call tcp_rwnd_set() to finish the
* setting.
*
* Note if there is a rpipe metric associated with the remote host,
* we should not inherit receive window size from listener.
*/
if (eager->tcp_snd_ws_ok)
/*
* Note that this is the only place tcp_rwnd_set() is called for
* accepting a connection. We need to call it here instead of
* after the 3-way handshake because we need to tell the other
* side our rwnd in the SYN-ACK segment.
*/
/* Put a ref on the listener for the eager. */
/* Set tcp_listener before adding it to tcp_conn_fanout */
/*
* Set tcp_listen_cnt so that when the connection is done, the counter
* is decremented.
*/
/*
* Tag this detached tcp vector for later retrieval
* by our listener client in tcp_accept().
*/
/*
* -1 is "special" and defined in TPI as something
* that should never be used in T_CONN_IND
*/
}
if (listener->tcp_syn_defense) {
/* Don't drop the SYN that comes from a good IP source */
}
}
/*
* We need to insert the eager in its own perimeter but as soon
* as we do that, we expose the eager to the classifier and
* should not touch any field outside the eager's perimeter.
* So do all the work necessary before inserting the eager
* in its own perimeter. Be optimistic that conn_connect()
* will succeed but undo everything if it fails.
*/
/*
* Increment the ref count as we are going to
* enqueueing an mp in squeue
*/
goto error;
}
/*
* We need to start the rto timer. In normal case, we start
* the timer after sending the packet on the wire (or at
* least believing that packet was sent by waiting for
* conn_ip_output() to return). Since this is the first packet
* being sent on the wire for the eager, our initial tcp_rto
* is at least tcp_rexmit_interval_min which is a fairly
* large value to allow the algorithm to adjust slowly to large
* fluctuations of RTT during first few transmissions.
*
* Starting the timer first and then sending the packet in this
* case shouldn't make much difference since tcp_rexmit_interval_min
* is of the order of several 100ms and starting the timer
* first and then sending the packet will result in difference
* of few micro seconds.
*
* Without this optimization, we are forced to hold the fanout
* lock across the ipcl_bind_insert() and sending the packet
* so that we don't race against an incoming packet (maybe RST)
* for this eager.
*
* It is necessary to acquire an extra reference on the eager
* at this point and hold it until after tcp_send_data() to
* ensure against an eager close race.
*/
/*
* Insert the eager in its own perimeter now. We are ready to deal
* with any packets on eager.
*/
if (ipcl_conn_insert(econnp) != 0)
goto error;
/*
* Send the SYN-ACK. Use the right squeue so that conn_ixa is
* only used by one thread at a time.
*/
} else {
}
return;
/*
* If a connection already exists, send the mp to that connections so
* that it can be appropriately dealt with.
*/
if (!IPCL_IS_CONNECTED(econnp)) {
/*
* Something bad happened. ipcl_conn_insert()
* failed because a connection already existed
* in connected hash but we can't find it
* anymore (someone blew it away). Just
* free this message and hopefully remote
* will retransmit at which time the SYN can be
* treated as a new connection or dealth with
* a TH_RST if a connection already exists.
*/
} else {
}
} else {
/* Nobody wants this packet */
}
return;
if (tlc_set)
}
/*
* In an ideal case of vertical partition in NUMA architecture, its
* beneficial to have the listener and all the incoming connections
* tied to the same squeue. The other constraint is that incoming
* connections should be tied to the squeue attached to interrupted
* CPU for obvious locality reason so this leaves the listener to
* be tied to the same squeue. Our only problem is that when listener
* is binding, the CPU that will get interrupted by the NIC whose
* IP address the listener is binding to is not even known. So
* the code below allows us to change that binding at the time the
* CPU is interrupted by virtue of incoming connection's squeue.
*
* This is usefull only in case of a listener bound to a specific IP
* address. For other kind of listeners, they get bound the
* very first time and there is no attempt to rebind them.
*/
void
{
/*
* IP sets ira_sqp to either the senders conn_sqp (for loopback)
* or based on the ring (for packets from GLD). Otherwise it is
* set based on lbolt i.e., a somewhat random number.
*/
goto done;
/*
* No one from read or write side can access us now
* except for already queued packets on this squeue.
* But since we haven't changed the squeue yet, they
* can't execute. If they are processed after we have
* changed the squeue, they are sent back to the
* correct squeue down below.
* But a listner close can race with processing of
* incoming SYN. If incoming SYN processing changes
* the squeue then the listener close which is waiting
* to enter the squeue would operate on the wrong
* squeue. Hence we don't change the squeue here unless
* the refcount is exactly the minimum refcount. The
* minimum refcount of 4 is counted as - 1 each for
* TCP and IP, 1 for being in the classifier hash, and
* 1 for the mblk being processed.
*/
goto done;
}
/* No special MT issues for outbound ixa_sqp hint */
}
do {
/*
* Assume we have picked a good squeue for the listener. Make
* subsequent SYNs not try to change the squeue.
*/
}
done:
} else {
}
}
/*
* Send up all messages queued on tcp_rcv_list.
*/
{
#ifdef DEBUG
#endif
/* Can't drain on an eager connection */
return (ret);
/* Can't be a non-STREAMS connection */
/* No need for the push timer now. */
if (tcp->tcp_push_tid != 0) {
tcp->tcp_push_tid = 0;
}
/*
* Handle two cases here: we are currently fused or we were
* previously fused and have some urgent data to be delivered
* upstream. The latter happens because we either ran out of
* memory or were detached and therefore sending the SIGURG was
* deferred until this point. In either case we pass control
* over to tcp_fuse_rcv_drain() since it may need to complete
* some work.
*/
return (ret);
}
#ifdef DEBUG
#endif
/* Does this need SSL processing first? */
continue;
}
}
#ifdef DEBUG
#endif
tcp->tcp_rcv_cnt = 0;
if (canputnext(q))
return (tcp_rwnd_reopen(tcp));
return (ret);
}
/*
* Queue data on tcp_rcv_list which is a b_next chain.
* tcp_rcv_last_head/tail is the last element of this chain.
* Each element of the chain is a b_cont chain.
*
* M_DATA messages are added to the current element.
* Other messages are added as new (b_next) elements.
*/
void
{
if (is_system_labeled()) {
/*
* Provide for protocols above TCP such as RPC. NOPID leaves
* db_cpid unchanged.
* The cred could have already been set.
*/
}
} else {
}
}
/* Generate an ACK-only (no data) segment for a TCP endpoint */
mblk_t *
{
/*
* There are a few cases to be considered while setting the sequence no.
* Essentially, we can come here while processing an unacceptable pkt
* in the TCPS_SYN_RCVD state, in which case we set the sequence number
* to snxt (per RFC 793), note the swnd wouldn't have been set yet.
* If we are here for a zero window probe, stick with suna. In all
* other cases, we check if suna + swnd encompasses snxt and set
* the sequence number to snxt, if so. If snxt falls outside the
* window (the receiver probably shrunk its window), we will go with
* suna + swnd, otherwise the sequence no will be unacceptable to the
* receiver.
*/
if (tcp->tcp_zero_win_probe) {
} else {
}
if (tcp->tcp_valid_bits) {
/*
* For the complex case where we have to send some
* controls (FIN or SYN), let tcp_xmit_mp do it.
*/
} else {
/* Generate a simple ACK */
int data_length;
int32_t num_sack_blk = 0;
/*
* Allocate space for TCP + IP headers
* and link-level header
*/
} else {
}
if (!mp1)
return (NULL);
/* Update the latest receive window size in TCP header. */
/* copy in prototype TCP + IP header */
/* Set the TCP sequence number. */
/* Set up the TCP flag field. */
if (tcp->tcp_ecn_echo_on)
tcp->tcp_rack_cnt = 0;
/* fill in timestamp option if in use */
if (tcp->tcp_snd_ts_ok) {
}
/* Fill in SACK options */
if (num_sack_blk > 0) {
int32_t i;
wptr[0] = TCPOPT_NOP;
sizeof (sack_blk_t);
for (i = 0; i < num_sack_blk; i++) {
}
}
} else {
}
/*
* Prime pump for checksum calculation in IP. Include the
* adjustment for a source route if any.
*/
if (tcp->tcp_ip_forward_progress) {
} else {
}
return (mp1);
}
}
/*
* Handle M_DATA messages from IP. Its called directly from IP via
* squeue for received IP packets.
*
* There are no exceptions to this rule. The caller has already put
* the squeue will do the refrele.
*
* The TH_SYN for the listener directly go to tcp_input_listener via
* squeue. ICMP errors go directly to tcp_icmp_input().
*
* sqp: NULL = recursive, sqp != NULL means called from squeue
*/
void
{
int seg_len;
int urp;
int npkt;
int mss;
/*
* RST from fused tcp loopback peer should trigger an unfuse.
*/
}
/*
* Record packet information in the ip_pkt_t
*/
ipp.ipp_fields = 0;
B_FALSE);
} else {
/*
* IPv6 packets can only be received by applications
* that are prepared to receive IPv6 addresses.
* The IP fanout must ensure this.
*/
&nexthdrp);
/* Could have caused a pullup? */
}
}
do {
}
return;
}
/*
* This is the correct place to update tcp_last_recv_time. Note
* that it is also updated for tcp structure that belongs to
* global and listener queues which do not really need updating.
* But that should not cause any harm. And it is updated for
* all kinds of incoming segments, not only for data segments.
*/
}
/*
* TCP can't handle urgent pointers that arrive before
* the connection has been accept()ed since it can't
* buffer OOB data. Discard segment if this happens.
*
* We can't just rely on a non-null tcp_listener to indicate
* that the accept() has completed since unlinking of the
* eager and completion of the accept are not atomic.
* tcp_detached, when it is not set (B_FALSE) indicates
* that the accept() has completed.
*
* Nor can it reassemble urgent pointers, so discard
* if it's not the next segment expected.
*
* Otherwise, collapse chain into one mblk (discard if
* that fails). This makes sure the headers, retransmitted
* data, and new data all are in the same mblk.
*/
return;
}
/* Update pointers into message */
/*
* Since we can't handle any data with this urgent
* pointer that is out of sequence, we expunge
* the data. This allows us to still register
* the urgent mark and generate the M_PCSIG,
* which we can do.
*/
seg_len = 0;
}
}
case TCPS_SYN_SENT:
return;
}
}
/*
* Note that our stack cannot send data before a
* connection is established, therefore the
* following check is valid. Otherwise, it has
* to be changed.
*/
return;
tcp_xmit_ctl("TCPS_SYN_SENT-Bad_seq",
return;
}
}
return;
}
return;
}
/* Process all TCP options. */
/*
* The following changes our rwnd to be a multiple of the
* MIN(peer MSS, our MSS) for performance reason.
*/
/* Is the other end ECN capable? */
if (tcp->tcp_ecn_ok) {
}
}
/*
* Clear ECN flags because it may interfere with later
* processing.
*/
if (!TCP_IS_DETACHED(tcp)) {
/* Allocate room for SACK options if needed. */
if (tcp->tcp_snd_sack_ok)
if (!tcp->tcp_loopback)
connp->conn_wroff);
}
/*
* If we can't get the confirmation upstream, pretend
* we didn't even see this one.
*
* XXX: how can we pretend we didn't see it if we
* have updated rnxt et. al.
*
* For loopback we defer sending up the T_CONN_CON
* until after some checks below.
*/
/*
* tcp_sendmsg() checks tcp_state without entering
* the squeue so tcp_state should be updated before
* sending up connection confirmation
*/
return;
}
/* SYN was acked - making progress */
/* One for the SYN */
/*
* If SYN was retransmitted, need to reset all
* retransmission info. This is because this
* segment will be treated as a dup ACK.
*/
if (tcp->tcp_rexmit) {
tcp->tcp_ms_we_have_waited = 0;
/*
* Set tcp_cwnd back to 1 MSS, per
* recommendation from
* Increasing TCP's Initial Window.
*/
}
/*
* Always send the three-way handshake ack immediately
* in order to make the connection complete as soon as
* possible on the accepting host.
*/
flags |= TH_ACK_NEEDED;
/*
* Special case for loopback. At this point we have
* received SYN-ACK from the remote endpoint. In
* order to ensure that both endpoints reach the
* fused state prior to any data exchange, the final
* ACK needs to be sent before we indicate T_CONN_CON
* to the module upstream.
*/
if (tcp->tcp_loopback) {
/*
* For loopback, we always get a pure SYN-ACK
* and only need to send back the final ACK
* with no data (this is because the other
* final ACK triggers the passive side to
* perform fusion in ESTABLISHED state.
*/
if (tcp->tcp_ack_tid != 0) {
(void) TCP_TIMER_CANCEL(tcp,
tcp->tcp_ack_tid);
tcp->tcp_ack_tid = 0;
}
if (!IPCL_IS_NONSTR(connp)) {
/* Send up T_CONN_CON */
}
} else {
(*connp->conn_upcalls->
}
return;
}
/*
* Forget fusion; we need to handle more
* complex cases below. Send the deferred
* T_CONN_CON message upstream and proceed
* as usual. Mark this tcp as not capable
* of fusion.
*/
if (!IPCL_IS_NONSTR(connp)) {
}
} else {
}
}
/*
* Check to see if there is data to be sent. If
* yes, set the transmit flag. Then check to see
* if received data processing needs to be done.
* If not, go straight to xmit_check. This short
*/
if (tcp->tcp_unsent)
flags |= TH_XMIT_NEEDED;
goto xmit_check;
}
seg_seq++;
break;
}
}
return;
case TCPS_SYN_RCVD:
/*
* In this state, a SYN|ACK packet is either bogus
* because the other side must be ACKing our SYN which
* indicates it has seen the ACK for their SYN and
* shouldn't retransmit it or we're crossing SYNs
* on active open.
*/
tcp_xmit_ctl("TCPS_SYN_RCVD-bad_syn",
return;
}
/*
* NOTE: RFC 793 pg. 72 says this should be
* tcp->tcp_suna <= seg_ack <= tcp->tcp_snxt
* but that would mean we have an ack that ignored
* our SYN.
*/
tcp_xmit_ctl("TCPS_SYN_RCVD-bad_ack",
return;
}
/*
* No sane TCP stack will send such a small window
* without receiving any data. Just drop this invalid
* ACK. We also shorten the abort timeout in case
* this is an attack.
*/
return;
}
}
break;
case TCPS_LISTEN:
/*
* Only a TLI listener can come through this path when a
* acceptor is going back to be a listener and a packet
* for the acceptor hits the classifier. For a socket
* listener, this can never happen because a listener
* can never accept connection on itself and hence a
* socket acceptor can not go back to being a listener.
*/
/*FALLTHRU*/
case TCPS_CLOSED:
case TCPS_BOUND: {
/*
* Don't accept any input on a closed tcp as this TCP logically
* does not exist on the system. Don't proceed further with
* this TCP. For instance, this packet could trigger another
* close of this tcp which would be disastrous for tcp_refcnt.
* tcp_close_detached / tcp_clean_death / tcp_closei_local must
* be called at most once on a TCP. In this case we need to
* refeed the packet into the classifier and figure out where
* the packet should go.
*/
/* Drops ref on new_connp */
return;
}
/* We failed to classify. For now just drop the packet */
return;
}
case TCPS_IDLE:
/*
* Handle the case where the tcp_clean_death() has happened
* on a connection (application hasn't closed yet) but a packet
* was already queued on squeue before tcp_clean_death()
* was processed. Calling tcp_clean_death() twice on same
* connection can result in weird behaviour.
*/
return;
default:
break;
}
/*
* If this is a detached connection and not an eager
* connection hanging off a listener then new data
* (past the FIN) will cause a reset.
* We do a special check here where it
* is out of the main line, rather than check
* if we are detached every time we see new
* data down below.
*/
if (TCP_IS_DETACHED_NONEAGER(tcp) &&
/*
* This could be an SSL closure alert. We're detached so just
* acknowledge it this last time.
*/
flags |= TH_ACK_NEEDED;
goto ack_check;
}
return;
}
if (tcp->tcp_snd_ts_ok) {
/*
* This segment is not acceptable.
* Drop it and send back an ACK.
*/
flags |= TH_ACK_NEEDED;
goto ack_check;
}
} else if (tcp->tcp_snd_sack_ok) {
/*
* SACK info in already updated in tcp_parse_options. Ignore
* all other TCP options...
*/
}
/*
* gap is the amount of sequence space between what we expect to see
* and what we got for seg_seq. A positive value for gap means
* something got lost. A negative value means we got some old stuff.
*/
if (gap < 0) {
/* Old stuff present. Is the SYN in there? */
(seg_len != 0)) {
seg_seq++;
urp--;
/* Recompute the gaps after noting the SYN. */
goto try_again;
}
/* Remove the old stuff from seg_len. */
/*
* Anything left?
* Make sure to check for unack'd FIN when rest of data
* has been previously ack'd.
*/
/*
* Resets are only valid if they lie within our offered
* window. If the RST bit is set, we just ignore this
* segment.
*/
return;
}
/*
* The arriving of dup data packets indicate that we
* may have postponed an ack for too long, or the other
* side's RTT estimate is out of shape. Start acking
* more often.
*/
tcp->tcp_rack_abs_max--;
}
/*
* This segment is "unacceptable". None of its
* sequence space lies within our advertized window.
*
* Adjust seg_len to the original value for tracing.
*/
if (connp->conn_debug) {
"tcp_rput: unacceptable, gap %d, rgap %d, "
"flags 0x%x, seg_seq %u, seg_ack %u, "
"seg_len %d, rnxt %u, snxt %u, %s",
}
/*
* Arrange to send an ACK in response to the
* unacceptable segment per RFC 793 page 69. There
* is only one small difference between ours and the
* acceptability test in the RFC - we accept ACK-only
* packet with SEG.SEQ = RCV.NXT+RCV.WND and no ACK
* will be generated.
*
* Note that we have to ACK an ACK-only packet at least
* for stacks that send 0-length keep-alives with
* SEG.SEQ = SND.NXT-1 as recommended by RFC1122,
* section 4.2.3.6. As long as we don't ever generate
* an unacceptable packet in response to an incoming
* packet that is unacceptable, it should not cause
* "ACK wars".
*/
flags |= TH_ACK_NEEDED;
/*
* Continue processing this segment in order to use the
* ACK information it contains, but skip all other
* sequence-number processing. Processing the ACK
* information is necessary in order to
* re-synchronize connections that may have lost
* synchronization.
*
* We clear seg_len and flag fields related to
* sequence number processing as they are not
* to be trusted for an unacceptable segment.
*/
seg_len = 0;
goto process_ack;
}
/* Fix seg_seq, and chew the gap off the front. */
do {
if (gap > 0) {
break;
}
} while (gap < 0);
/*
* If the urgent data has already been acknowledged, we
* should ignore TH_URG below
*/
if (urp < 0)
}
/*
* rgap is the amount of stuff received out of window. A negative
* value is the amount out of window.
*/
if (rgap < 0) {
} else {
}
/*
* seg_len does not include the FIN, so if more than
* just the FIN is out of window, we act like we don't
* see it. (If just the FIN is out of window, rgap
* will be zero and we will go ahead and acknowledge
* the FIN.)
*/
/* Fix seg_len and make sure there is something left. */
if (seg_len <= 0) {
/*
* Resets are only valid if they lie within our offered
* window. If the RST bit is set, we just ignore this
* segment.
*/
return;
}
/* Per RFC 793, we need to send back an ACK. */
flags |= TH_ACK_NEEDED;
/*
* Send SIGURG as soon as possible i.e. even
* if the TH_URG was delivered in a window probe
* packet (which will be unacceptable).
*
* We generate a signal if none has been generated
* for this connection or if this is a new urgent
* byte. Also send a zero-length "unmarked" message
* to inform SIOCATMARK that this is not the mark.
*
* tcp_urp_last_valid is cleared when the T_exdata_ind
* is sent up. This plus the check for old data
* (gap >= 0) handles the wraparound of the sequence
* number space without having to always track the
* correct MAX(tcp_urp_last, tcp_rnxt). (BSD tracks
* this max in its rcv_up variable).
*
* This prevents duplicate SIGURGS due to a "late"
* zero-window probe when the T_EXDATA_IND has already
* been sent up.
*/
tcp->tcp_urp_last))) {
if (IPCL_IS_NONSTR(connp)) {
if (!TCP_IS_DETACHED(tcp)) {
(*connp->conn_upcalls->
urp);
}
} else {
return;
}
if (!TCP_IS_DETACHED(tcp) &&
/* Try again on the rexmit. */
return;
}
/*
* If the next byte would be the mark
* then mark with MARKNEXT else mark
* with NOTMARKNEXT.
*/
else
}
}
/*
* If this is a zero window probe, continue to
* process the ACK part. But we need to set seg_len
* to 0 to avoid data processing. Otherwise just
* drop the segment and send back an ACK.
*/
seg_len = 0;
goto process_ack;
} else {
goto ack_check;
}
}
/* Pitch out of window stuff off the end. */
do {
if (rgap < 0) {
}
break;
}
}
ok:;
/*
* TCP should check ECN info for segments inside the window only.
* Therefore the check should be done here.
*/
if (tcp->tcp_ecn_ok) {
}
/*
* Note that both ECN_CE and CWR can be set in the
* same segment. In this case, we once again turn
* on ECN_ECHO.
*/
}
} else {
}
}
}
/*
* Check whether we can update tcp_ts_recent. This test is
* NOT the one in RFC 1323 3.4. It is from Braden, 1993, "TCP
* Extensions for High Performance: An Update", Internet Draft.
*/
if (tcp->tcp_snd_ts_ok &&
}
/*
* FIN in an out of order segment. We record this in
* tcp_valid_bits and the seq num of FIN in tcp_ofo_fin_seq.
* Clear the FIN so that any check on FIN flag will fail.
* Remember that FIN also counts in the sequence number
* space. So we need to ack out of order FIN only segments.
*/
flags |= TH_ACK_NEEDED;
}
if (seg_len > 0) {
/* Fill in the SACK blk list. */
if (tcp->tcp_snd_sack_ok) {
&(tcp->tcp_num_sack_blk));
}
/*
* Attempt reassembly and see if we have something
* ready to go.
*/
/* Always ack out of order packets */
if (mp) {
/*
* A gap is filled and the seq num and len
* of the gap match that of a previously
* received FIN, put the FIN flag back in.
*/
tcp->tcp_valid_bits &=
}
if (tcp->tcp_reass_tid != 0) {
(void) TCP_TIMER_CANCEL(tcp,
tcp->tcp_reass_tid);
/*
* Restart the timer if there is still
* data in the reassembly queue.
*/
} else {
tcp->tcp_reass_tid = 0;
}
}
} else {
/*
* Keep going even with NULL mp.
* There may be a useful ACK or something else
* we don't want to miss.
*
* But TCP should not perform fast retransmit
* because of the ack number. TCP uses
* seg_len == 0 to determine if it is a pure
* ACK. And this is not a pure ACK.
*/
seg_len = 0;
if (tcps->tcps_reass_timeout != 0 &&
tcp->tcp_reass_tid == 0) {
}
}
}
} else if (seg_len > 0) {
/*
* If an out of order FIN was received before, and the seq
* num and len of the new segment match that of the FIN,
* put the FIN flag back in.
*/
}
}
case TCPS_SYN_RCVD:
break;
case TCPS_ESTABLISHED:
case TCPS_FIN_WAIT_1:
case TCPS_FIN_WAIT_2:
case TCPS_CLOSE_WAIT:
break;
case TCPS_CLOSING:
case TCPS_LAST_ACK:
(void) tcp_clean_death(tcp, 0);
break;
default:
break;
}
return;
}
/*
* See RFC 793, Page 71
*
* The seq number must be in the window as it should
* be "fixed" above. If it is outside window, it should
* be already rejected. Note that we allow seg_seq to be
* rnxt + rwnd because we want to accept 0 window probe.
*/
/*
* If the ACK flag is not set, just use our snxt as the
* seq number of the RST segment.
*/
}
return;
}
/*
* urp could be -1 when the urp field in the packet is 0
* and TCP_OLD_URP_INTERPRETATION is set. This implies that the urgent
* byte was at seg_seq - 1, in which case we ignore the urgent flag.
*/
if (!tcp->tcp_urp_last_valid ||
/*
* Non-STREAMS sockets handle the urgent data a litte
* differently from STREAMS based sockets. There is no
* need to mark any mblks with the MSG{NOT,}MARKNEXT
* flags to keep SIOCATMARK happy. Instead a
* su_signal_oob upcall is made to update the mark.
* Neither is a T_EXDATA_IND mblk needed to be
* prepended to the urgent data. The urgent data is
* delivered using the su_recv upcall, where we set
* the MSG_OOB flag to indicate that it is urg data.
*
* Neither TH_SEND_URP_MARK nor TH_MARKNEXT_NEEDED
* are used by non-STREAMS sockets.
*/
if (IPCL_IS_NONSTR(connp)) {
if (!TCP_IS_DETACHED(tcp)) {
}
} else {
/*
* If we haven't generated the signal yet for
* this urgent pointer value, do it now. Also,
* send up a zero-length M_DATA indicating
* whether or not this is the mark. The latter
* is not needed when a T_EXDATA_IND is sent up.
* However, if there are allocation failures
* this code relies on the sender retransmitting
* and the socket code for determining the mark
* should not block waiting for the peer to
* transmit. Thus, for simplicity we always
* send up the mark indication.
*/
return;
}
if (!TCP_IS_DETACHED(tcp) &&
SIGURG)) {
/* Try again on the rexmit. */
return;
}
/*
* Mark with NOTMARKNEXT for now.
* The code below will change this to MARKNEXT
* if we are at the mark.
*
* If there are allocation failures (e.g. in
* dupmsg below) the next time tcp_input_data
* sees the urgent segment it will send up the
* MSGMARKNEXT message.
*/
#ifdef DEBUG
"tcp_rput: sent M_PCSIG 2 seq %x urp %x "
"last %x, %s",
#endif /* DEBUG */
}
/*
* An allocation failure prevented the previous
* tcp_input_data from sending up the allocated
* MSG*MARKNEXT message - send it up this time
* around.
*/
}
/*
* If the urgent byte is in this segment, make sure that it is
* all by itself. This makes it much easier to deal with the
* possibility of an allocation failure on the T_exdata_ind.
* Note that seg_len is the number of bytes in the segment, and
* urp is the offset into the segment of the urgent byte.
* urp < seg_len means that the urgent byte is in this segment.
*/
if (seg_len != 1) {
/*
* Break it up and feed it back in.
* Re-attach the IP header.
*/
if (urp > 0) {
/*
* There is stuff before the urgent
* byte.
*/
if (!mp1) {
/*
* Trim from urgent byte on.
* The rest will come back.
*/
return;
}
/* Feed this piece back in. */
/*
* If the data passed back in was not
* processed (ie: bad ACK) sending
* the remainder back in will cause a
* loop. In this case, drop the
* packet and let the sender try
* sending a good packet.
*/
return;
}
}
/*
* There is stuff after the urgent
* byte.
*/
if (!mp1) {
/*
* Trim everything beyond the
* urgent byte. The rest will
* come back.
*/
return;
}
/*
* If the data passed back in was not
* processed (ie: bad ACK) sending
* the remainder back in will cause a
* loop. In this case, drop the
* packet and let the sender try
* sending a good packet.
*/
return;
}
}
return;
}
/*
* This segment contains only the urgent byte. We
* have to allocate the T_exdata_ind, if we can.
*/
if (IPCL_IS_NONSTR(connp)) {
int error;
/*
* We should never be in middle of a
* fallback, the squeue guarantees that.
*/
goto update_ack;
} else if (!tcp->tcp_urp_mp) {
struct T_exdata_ind *tei;
BPRI_MED);
if (!mp1) {
/*
* Sigh... It'll be back.
* Generate any MSG*MARK message now.
*/
seg_len = 0;
if (flags & TH_SEND_URP_MARK) {
}
goto ack_check;
}
#ifdef DEBUG
"tcp_rput: allocated exdata_ind %s",
#endif /* DEBUG */
/*
* There is no need to send a separate MSG*MARK
* message since the T_EXDATA_IND will be sent
* now.
*/
flags &= ~TH_SEND_URP_MARK;
}
/*
* Now we are all set. On the next putnext upstream,
* tcp_urp_mp will be non-NULL and will get prepended
* to what has to be this piece containing the urgent
* byte. If for any reason we abort this segment below,
* if it comes back, we will have this ready, or it
* will get blown off in close.
*/
/*
* The urgent byte is the next byte after this sequence
* number. If this endpoint is non-STREAMS, then there
* is nothing to do here since the socket has already
* been notified about the urg pointer by the
* su_signal_oob call above.
*
* In case of STREAMS, some more work might be needed.
* If there is data it is marked with MSGMARKNEXT and
* and any tcp_urp_mark_mp is discarded since it is not
* needed. Otherwise, if the code above just allocated
* a zero-length tcp_urp_mark_mp message, that message
* is tagged with MSGMARKNEXT. Sending up these
* MSGMARKNEXT messages makes SIOCATMARK work correctly
* even though the T_EXDATA_IND will not be sent up
* until the urgent byte arrives.
*/
if (seg_len != 0) {
flags &= ~TH_SEND_URP_MARK;
}
}
#ifdef DEBUG
"tcp_rput: AT MARK, len %d, flags 0x%x, %s",
#endif /* DEBUG */
}
#ifdef DEBUG
else {
/* Data left until we hit mark */
"tcp_rput: URP %d bytes left, %s",
}
#endif /* DEBUG */
}
goto xmit_check;
}
}
if (bytes_acked > 0)
/* 3-way handshake complete - pass up the T_CONN_IND */
/*
* We are here means eager is fine but it can
* get a TH_RST at any point between now and till
* accept completes and disappear. We need to
* ensure that reference to eager is valid after
* we get out of eager's perimeter. So we do
* an extra refhold.
*/
/*
* The listener also exists because of the refhold
* done in tcp_input_listener. Its possible that it
* might have closed. We will check that once we
* get inside listeners context.
*/
/*
* We optimize by not calling an SQUEUE_ENTER
* on the listener since we know that the
* listener and eager squeues are the same.
* We are able to make this check safely only
* because neither the eager nor the listener
* can change its squeue. Only an active connect
* can change its squeue
*/
} else if (!tcp->tcp_loopback) {
} else {
}
}
/*
* We are seeing the final ack in the three way
* hand shake of a active open'ed connection
* so we must send up a T_CONN_CON
*
* tcp_sendmsg() checks tcp_state without entering
* the squeue so tcp_state should be updated before
* sending up connection confirmation.
*/
if (tcp->tcp_active_open) {
return;
}
/*
* Don't fuse the loopback endpoints for
* simultaneous active opens.
*/
if (tcp->tcp_loopback) {
}
}
bytes_acked--;
/* SYN was acked - making progress */
/*
* If SYN was retransmitted, need to reset all
* retransmission info as this segment will be
* treated as a dup ACK.
*/
if (tcp->tcp_rexmit) {
tcp->tcp_ms_we_have_waited = 0;
}
/*
* We set the send window to zero here.
* This is needed if there is data to be
* processed already on the queue.
* Later (at swnd_update label), the
* "new_swnd > tcp_swnd" condition is satisfied
* the XMIT_NEEDED flag is set in the current
* (SYN_RCVD) state. This ensures tcp_wput_data() is
* called if there is already data on queue in
* this state.
*/
/* Fuse when both sides are in ESTABLISHED state */
}
/* This code follows 4.4BSD-Lite2 mostly. */
if (bytes_acked < 0)
goto est;
/*
* If TCP is ECN capable and the congestion experience bit is
* set, reduce tcp_cwnd and tcp_ssthresh. But this should only be
* done once per window (or more loosely, per RTT).
*/
/*
* If the cwnd is 0, use the timer to clock out
* new segments. This is required by the ECN spec.
*/
if (npkt == 0) {
/*
* This makes sure that when the ACK comes
* back, we will increase tcp_cwnd by 1 MSS.
*/
tcp->tcp_cwnd_cnt = 0;
}
/*
* This marks the end of the current window of in
* flight data. That is why we don't use
* tcp_suna + tcp_swnd. Only data in flight can
* provide ECN info.
*/
}
}
if (bytes_acked == 0) {
int dupack_cnt;
/*
* Fast retransmit. When we have seen exactly three
* identical ACKs while we have unacked data
* outstanding we take it as a hint that our peer
* dropped something.
*
* If TCP is retransmitting, don't do fast retransmit.
*/
! tcp->tcp_rexmit) {
/* Do Limited Transmit */
/*
* RFC 3042
*
* What we need to do is temporarily
* increase tcp_cwnd so that new
* data can be sent if it is allowed
* by the receive window (tcp_rwnd).
* tcp_wput_data() will take care of
* the rest.
*
* If the connection is SACK capable,
* only do limited xmit when there
* is SACK info.
*
* Note how tcp_cwnd is incremented.
* The first dup ACK will increase
* it by 1 MSS. The second dup ACK
* will increase it by 2 MSS. This
* means that only 1 new segment will
* be sent for each dup ACK.
*/
if (tcp->tcp_unsent > 0 &&
(!tcp->tcp_snd_sack_ok ||
(tcp->tcp_snd_sack_ok &&
flags |= TH_LIMIT_XMIT;
}
} else if (dupack_cnt ==
/*
* If we have reduced tcp_ssthresh
* because of ECN, do not reduce it again
* unless it is already one window of data
* away. After one window of data, tcp_cwr
* should then be cleared. Note that
* for non ECN capable connection, tcp_cwr
* should always be false.
*
* Adjust cwnd since the duplicate
* ack indicates that a packet was
* dropped (due to congestion.)
*/
mss;
}
if (tcp->tcp_ecn_ok) {
}
/*
* We do Hoe's algorithm. Refer to her
* paper "Improving the Start-up Behavior
* of a Congestion Control Scheme for TCP,"
* appeared in SIGCOMM'96.
*
* Save highest seq no we have sent so far.
* Be careful about the invisible FIN byte.
*/
(tcp->tcp_unsent == 0)) {
} else {
}
/*
* Do not allow bursty traffic during.
* fast recovery. Refer to Fall and Floyd's
* paper "Simulation-based Comparisons of
* Tahoe, Reno and SACK TCP" (in CCR?)
* This is a best current practise.
*/
/*
* For SACK:
* Calculate tcp_pipe, which is the
* estimated number of bytes in
* network.
*
* tcp_fack is the highest sack'ed seq num
* TCP has received.
*
* tcp_pipe is explained in the above quoted
* Fall and Floyd's paper. tcp_fack is
* explained in Mathis and Mahdavi's
* "Forward Acknowledgment: Refining TCP
* Congestion Control" in SIGCOMM '96.
*/
if (tcp->tcp_snd_sack_ok) {
} else {
/*
* Always initialize tcp_pipe
* even though we don't have
* any SACK info. If later
* we get SACK info and
* tcp_pipe is not initialized,
* funny things will happen.
*/
}
} else {
} /* tcp_snd_sack_ok */
} else {
/*
* Here we perform congestion
* avoidance, but NOT slow start.
* This is known as the Fast
* Recovery Algorithm.
*/
if (tcp->tcp_snd_sack_ok &&
} else {
/*
* We know that one more packet has
* left the pipe thus we can update
* cwnd.
*/
if (tcp->tcp_unsent > 0)
flags |= TH_XMIT_NEEDED;
}
}
}
} else if (tcp->tcp_zero_win_probe) {
/*
* If the window has opened, need to arrange
* to send additional data.
*/
if (new_swnd != 0) {
/* tcp_suna != tcp_snxt */
/* Packet contains a window update */
tcp->tcp_zero_win_probe = 0;
tcp->tcp_timer_backoff = 0;
tcp->tcp_ms_we_have_waited = 0;
/*
* Transmit starting with tcp_suna since
* the one byte probe is not ack'ed.
* If TCP has sent more than one identical
* probe, tcp_rexmit will be set. That means
* tcp_ss_rexmit() will send out the one
* byte along with new data. Otherwise,
* fake the retransmission.
*/
flags |= TH_XMIT_NEEDED;
if (!tcp->tcp_rexmit) {
tcp->tcp_dupack_cnt = 0;
}
}
}
goto swnd_update;
}
/*
* Check for "acceptability" of ACK value per RFC 793, pages 72 - 73.
* If the ACK value acks something that we have not yet sent, it might
* be an old duplicate segment. Send an ACK to re-synchronize the
* other side.
* Note: reset in response to unacceptable ACK in SYN_RECEIVE
* state is handled above, so we can always just drop the segment and
* send an ACK here.
*
* In the case where the peer shrinks the window, we see the new window
* update, but all the data sent previously is queued up by the peer.
* To account for this, in tcp_process_shrunk_swnd(), the sequence
* number, which was already sent, and within window, is recorded.
* tcp_snxt is then updated.
*
* If the window has previously shrunk, and an ACK for data not yet
* sent, according to tcp_snxt is recieved, it may still be valid. If
* the ACK is for data within the window at the time the window was
* shrunk, then the ACK is acceptable. In this case tcp_snxt is set to
* the sequence number ACK'ed.
*
* If the ACK covers all the data sent at the time the window was
* shrunk, we can now set tcp_is_wnd_shrnk to B_FALSE.
*
* Should we send ACKs in response to ACK only segments?
*/
if ((tcp->tcp_is_wnd_shrnk) &&
} else {
/* drop the received segment */
/*
* Send back an ACK. If tcp_drop_ack_unsent_cnt is
* greater than 0, check if the number of such
* bogus ACks is greater than that count. If yes,
* don't send back any ACK. This prevents TCP from
* getting into an ACK storm if somehow an attacker
* successfully spoofs an acceptable segment to our
* peer. If this continues (count > 2 X threshold),
* we should abort this connection.
*/
if (tcp_drop_ack_unsent_cnt > 0 &&
++tcp->tcp_in_ack_unsent >
}
return;
}
}
return;
}
tcp->tcp_snxt_shrunk)) {
}
/*
* TCP gets a new ACK, update the notsack'ed list to delete those
* blocks that are covered by this ACK.
*/
}
/*
* If we got an ACK after fast retransmit, check to see
* if it is a partial ACK. If it is not and the congestion
* window was inflated to account for the other side's
* cached packets, retract it. If it is, do Hoe's algorithm.
*/
tcp->tcp_dupack_cnt = 0;
/*
* Restore the orig tcp_cwnd_ssthresh after
* fast retransmit phase.
*/
}
tcp->tcp_cwnd_cnt = 0;
/*
* Remove all notsack info to avoid confusion with
* the next fast retrasnmit/recovery phase.
*/
if (tcp->tcp_snd_sack_ok &&
tcp);
}
} else {
if (tcp->tcp_snd_sack_ok &&
} else {
/*
* Hoe's algorithm:
*
* Retransmit the unack'ed segment and
* restart fast recovery. Note that we
* need to scale back tcp_cwnd to the
* original value when we started fast
* recovery. This is to prevent overly
* aggressive behaviour in sending new
* segments.
*/
}
}
} else {
tcp->tcp_dupack_cnt = 0;
if (tcp->tcp_rexmit) {
/*
* TCP is retranmitting. If the ACK ack's all
* outstanding data, update tcp_rexmit_max and
* tcp_rexmit_nxt. Otherwise, update tcp_rexmit_nxt
* to the correct value.
*
* Note that SEQ_LEQ() is used. This is to avoid
* unnecessary fast retransmit caused by dup ACKs
* received when TCP does slow start retransmission
* after a time out. During this phase, TCP may
* send out segments which are already received.
* This causes dup ACKs to be sent back.
*/
}
flags |= TH_XMIT_NEEDED;
}
} else {
}
tcp->tcp_ms_we_have_waited = 0;
}
}
if (tcp->tcp_zero_win_probe != 0) {
tcp->tcp_zero_win_probe = 0;
tcp->tcp_timer_backoff = 0;
}
/*
* If tcp_xmit_head is NULL, then it must be the FIN being ack'ed.
* Note that it cannot be the SYN being ack'ed. The code flow
* will not reach here.
*/
goto fin_acked;
}
/*
* Update the congestion window.
*
* If TCP is not ECN capable or TCP is ECN capable but the
* congestion experience bit is not set, increase the tcp_cwnd as
* usual.
*/
/*
* This is to prevent an increase of less than 1 MSS of
* tcp_cwnd. With partial increase, tcp_wput_data()
* may send out tinygrams in order to preserve mblk
* boundaries.
*
* By initializing tcp_cwnd_cnt to new tcp_cwnd and
* decrementing it by 1 MSS for every ACKs, tcp_cwnd is
* increased by 1 MSS for every RTTs.
*/
if (tcp->tcp_cwnd_cnt <= 0) {
} else {
add = 0;
}
}
}
/* See if the latest urgent data has been acknowledged */
/* Can we update the RTT estimates? */
if (tcp->tcp_snd_ts_ok) {
/* Ignore zero timestamp echo-reply. */
if (tcpopt.tcp_opt_ts_ecr != 0) {
}
/* If needed, restart the timer. */
tcp->tcp_set_timer = 0;
}
/*
* Update tcp_csuna in case the other side stops sending
* us timestamps.
*/
/*
* An ACK sequence we haven't seen before, so get the RTT
* and update the RTO. But first check if the timestamp is
* valid to use.
*/
else
/* Remeber the last sequence to be ACKed */
tcp->tcp_set_timer = 0;
}
} else {
}
/* Eat acknowledged bytes off the xmit queue. */
for (;;) {
if (bytes_acked < 0) {
/*
* Set a new timestamp if all the bytes timed by the
* old timestamp have been ack'ed.
*/
}
break;
}
/*
* This notification is required for some zero-copy
* clients to maintain a copy semantic. After the data
* is ack'ed, client is safe to modify or reuse the buffer.
*/
if (tcp->tcp_snd_zcopy_aware &&
if (bytes_acked == 0) {
/* Everything is ack'ed, clear the tail. */
/*
* Cancel the timer unless we are still
* waiting for an ACK for the FIN packet.
*/
if (tcp->tcp_timer_tid != 0 &&
(void) TCP_TIMER_CANCEL(tcp,
tcp->tcp_timer_tid);
tcp->tcp_timer_tid = 0;
}
goto pre_swnd_update;
}
break;
break;
}
/*
* More was acked but there is nothing more
* outstanding. This means that the FIN was
* just acked or that we're talking to a clown.
*/
if (tcp->tcp_fin_sent) {
/* FIN was acked - making progress */
if (!tcp->tcp_fin_acked)
if (tcp->tcp_linger_tid != 0 &&
tcp->tcp_linger_tid) >= 0) {
}
} else {
/*
* We should never get here because
* we have already checked that the
* number of bytes ack'ed should be
* smaller than or equal to what we
* have sent so far (it is the
* acceptability check of the ACK).
* We can only get here if the send
* queue is corrupted.
*
* Terminate the connection and
* panic the system. It is better
* for us to panic instead of
* continuing to avoid other disaster.
*/
panic("Memory corruption "
"detected for connection %s.",
/*NOTREACHED*/
}
goto pre_swnd_update;
}
}
if (tcp->tcp_unsent) {
flags |= TH_XMIT_NEEDED;
}
/*
* The following check is different from most other implementations.
* For bi-directional transfer, when segments are dropped, the
* "normal" check will not accept a window update in those
* retransmitted segemnts. Failing to do that, TCP may send out
* segments which are outside receiver's window. As TCP accepts
* the ack in those retransmitted segments, if the window update in
* the same segment is not accepted, TCP will incorrectly calculates
* that it can send more segments. This can create a deadlock
* with the receiver if its window becomes zero.
*/
/*
* The criteria for update is:
*
* 1. the segment acknowledges some data. Or
* 2. the segment is new, i.e. it has a higher seq num. Or
* 3. the segment is not old and the advertised window is
* larger than the previous advertised window.
*/
flags |= TH_XMIT_NEEDED;
}
est:
case TCPS_FIN_WAIT_1:
if (tcp->tcp_fin_acked) {
/*
* FIN_WAIT_2 flushing algorithm.
* If there is no user attached to this
* TCP endpoint, then this TCP struct
* could hang around forever in FIN_WAIT_2
* state if the peer forgets to send us
* a FIN. To prevent this, we wait only
* 2*MSL (a convenient time value) for
* the FIN to arrive. If it doesn't show up,
* we flush the TCP endpoint. This algorithm,
* though a violation of RFC-793, has worked
* for over 10 years in BSD systems.
* Note: SunOS 4.x waits 675 seconds before
* flushing the FIN_WAIT_2 connection.
*/
}
break;
case TCPS_FIN_WAIT_2:
break; /* Shutdown hook? */
case TCPS_LAST_ACK:
if (tcp->tcp_fin_acked) {
(void) tcp_clean_death(tcp, 0);
return;
}
goto xmit_check;
case TCPS_CLOSING:
if (tcp->tcp_fin_acked)
/*FALLTHRU*/
case TCPS_CLOSE_WAIT:
goto xmit_check;
default:
break;
}
}
/* Make sure we ack the fin */
flags |= TH_ACK_NEEDED;
if (!tcp->tcp_fin_rcvd) {
/*
* Generate the ordrel_ind at the end unless we
* are an eager guy.
* In the eager case tcp_rsrv will do this when run
* after tcp_accept is done.
*/
case TCPS_SYN_RCVD:
case TCPS_ESTABLISHED:
/* Keepalive? */
break;
case TCPS_FIN_WAIT_1:
if (!tcp->tcp_fin_acked) {
break;
}
/* FALLTHRU */
case TCPS_FIN_WAIT_2:
if (seg_len) {
/*
* implies data piggybacked on FIN.
* break to handle data.
*/
break;
}
goto ack_check;
}
}
}
goto xmit_check;
if (seg_len == 0) {
goto xmit_check;
}
/*
* The header has been consumed, so we remove the
* zero-length mblk here.
*/
}
tcp->tcp_rack_cnt++;
{
/*
* We have more unacked data than we should - send
* an ACK now.
*/
flags |= TH_ACK_NEEDED;
cur_max++;
else
} else if (TCP_IS_DETACHED(tcp)) {
/* We don't have an ACK timer for detached TCP. */
flags |= TH_ACK_NEEDED;
/*
* If we get a segment that is less than an mss, and we
* already have unacknowledged data, and the amount
* unacknowledged is not a multiple of mss, then we
* better generate an ACK now. Otherwise, this may be
* the tail piece of a transaction, and we would rather
* wait for the response.
*/
flags |= TH_ACK_NEEDED;
else
} else {
/* Start delayed ack timer */
}
}
goto xmit_check;
/* Update SACK list */
&(tcp->tcp_num_sack_blk));
}
if (tcp->tcp_urp_mp) {
/* Ready for a new signal. */
#ifdef DEBUG
"tcp_rput: sending exdata_ind %s",
#endif /* DEBUG */
}
/*
* Check for ancillary data changes compared to last segment.
*/
return;
}
/*
* Side queue inbound data until the accept happens.
* tcp_accept/tcp_rput drains this when the accept happens.
* M_DATA is queued on b_cont. Otherwise (T_OPTDATA_IND or
* T_EXDATA_IND) it is queued on b_next.
* XXX Make urgent data use this. Requires:
* Removing tcp_listener check for TH_URG
* Making M_PCPROTO and MARK messages skip the eager case
*/
if (tcp->tcp_kssl_pending) {
} else {
}
} else if (IPCL_IS_NONSTR(connp)) {
/*
* Non-STREAMS socket
*
* Note that no KSSL processing is done here, because
* KSSL is not supported for non-STREAMS sockets.
*/
int error;
/*
* We should never be in middle of a
* fallback, the squeue guarantees that.
*/
} else if (push) {
/* PUSH bit set and sockfs is not flow controlled */
}
} else {
/* STREAMS socket */
(flags & TH_MARKNEXT_NEEDED)) {
}
if (flags & TH_MARKNEXT_NEEDED) {
#ifdef DEBUG
"tcp_rput: sending MSGMARKNEXT %s",
#endif /* DEBUG */
flags &= ~TH_MARKNEXT_NEEDED;
}
/* Does this need SSL processing first? */
} else {
if (is_system_labeled())
}
/* Does this need SSL processing first? */
/*
* Enqueue the new segment first and then
* call tcp_rcv_drain() to send all data
* up. The other way to do this is to
* send all queued data up and then call
* putnext() to send the new segment up.
* This way can remove the else part later
* on.
*
* We don't do this to avoid one more call to
* canputnext() as tcp_rcv_drain() needs to
* call canputnext().
*/
} else {
if (is_system_labeled())
}
} else {
/*
* Enqueue all packets when processing an mblk
* from the co queue and also enqueue normal packets.
*/
}
/*
* Make sure the timer is running if we have data waiting
* for a push bit. This provides resiliency against
* implementations that do not correctly generate push bits.
*/
/*
* The connection may be closed at this point, so don't
* do anything for a detached tcp.
*/
if (!TCP_IS_DETACHED(tcp))
}
}
/* Is there anything left to do? */
TH_ORDREL_NEEDED|TH_SEND_URP_MARK)) == 0)
goto done;
/* Any transmit work to do and a non-zero window? */
if (flags & TH_REXMIT_NEEDED) {
B_TRUE);
(mblk_t *)LBOLT_FASTPATH;
snd_size);
}
}
if (flags & TH_NEED_SACK_REXMIT) {
}
/*
* For TH_LIMIT_XMIT, tcp_wput_data() is called to send
* out new segment. Note that tcp_rexmit should not be
* set, otherwise TH_LIMIT_XMIT should not be set.
*/
if (!tcp->tcp_rexmit) {
} else {
}
}
/*
* Adjust tcp_cwnd back to normal value after sending
* new data segments.
*/
if (flags & TH_LIMIT_XMIT) {
/*
* This will restart the timer. Restarting the
* timer is used to avoid a timeout before the
* limited transmitted segment's ACK gets back.
*/
(mblk_t *)LBOLT_FASTPATH;
}
/* Anything more to do? */
TH_ORDREL_NEEDED|TH_SEND_URP_MARK)) == 0)
goto done;
}
if (flags & TH_SEND_URP_MARK) {
/*
* Send up any queued data and then send the mark message
*/
}
if (is_system_labeled())
#ifdef DEBUG
"tcp_rput: sending zero-length %s %s",
"MSGNOTMARKNEXT"),
#endif /* DEBUG */
flags &= ~TH_SEND_URP_MARK;
}
if (flags & TH_ACK_NEEDED) {
/*
* Time to send an ack for some reason.
*/
}
if (tcp->tcp_ack_tid != 0) {
tcp->tcp_ack_tid = 0;
}
}
if (flags & TH_ACK_TIMER_NEEDED) {
/*
* Arrange for deferred ACK or push wait timeout.
* Start timer if it is not already running.
*/
if (tcp->tcp_ack_tid == 0) {
}
}
if (flags & TH_ORDREL_NEEDED) {
/*
* Send up the ordrel_ind unless we are an eager guy.
* In the eager case tcp_rsrv will do this when run
* after tcp_accept is done.
*/
if (IPCL_IS_NONSTR(connp)) {
goto done;
}
/*
* Push any mblk(s) enqueued from co processing.
*/
}
}
done:
}
/*
* Attach ancillary data to a received TCP segments for the
* ancillary pieces requested by the application that are
* different than they were in the previous data segment.
*
* Save the "current" values once memory allocation is ok so that
* when memory allocation fails we can just wait for the next data segment.
*/
static mblk_t *
{
struct T_optdata_ind *todi;
int optlen;
optlen = 0;
/* If app asked for pktinfo and the index has changed ... */
sizeof (struct in6_pktinfo);
}
/* If app asked for hoplimit and it has changed ... */
}
/* If app asked for tclass and it has changed ... */
}
/*
* If app asked for hopbyhop headers and it has changed ...
* For security labels, note that (1) security labels can't change on
* a connected socket at all, (2) we're connected to at most one peer,
* (3) if anything changes, then it must be some other extra option.
*/
return (mp);
}
/* If app asked for dst headers before routing headers ... */
return (mp);
}
/* If app asked for routing headers and it has changed ... */
return (mp);
}
/* If app asked for dest headers and it has changed ... */
return (mp);
}
if (optlen == 0) {
/* Nothing to add */
return (mp);
}
/*
* Defer sending ancillary data until the next TCP segment
* arrives.
*/
return (mp);
}
/*
* If app asked for pktinfo and the index has changed ...
* Note that the local address never changes for the connection.
*/
if (addflag.crb_ip_recvpktinfo) {
struct in6_pktinfo *pkti;
/* Save as "last" value */
}
/* If app asked for hoplimit and it has changed ... */
if (addflag.crb_ipv6_recvhoplimit) {
/* Save as "last" value */
}
/* If app asked for tclass and it has changed ... */
if (addflag.crb_ipv6_recvtclass) {
/* Save as "last" value */
}
if (addflag.crb_ipv6_recvhopopts) {
/* Save as last value */
}
if (addflag.crb_ipv6_recvrthdrdstopts) {
/* Save as last value */
}
if (addflag.crb_ipv6_recvrthdr) {
/* Save as last value */
}
if (addflag.crb_ipv6_recvdstopts) {
/* Save as last value */
}
return (mp);
}
/* The minimum of smoothed mean deviation in RTO calculation. */
#define TCP_SD_MIN 400
/*
* Set RTO for this connection. The formula is from Jacobson and Karels'
* "Congestion Avoidance and Control" in SIGCOMM '88. The variable names
* are the same as those in Appendix A.2 of that paper.
*
* m = new measurement
* sa = smoothed RTT average (8 * average estimates).
* sv = smoothed mean deviation (mdev) of RTT (4 * deviation estimates).
*/
static void
{
long m = TICK_TO_MSEC(rtt);
tcp->tcp_rtt_update++;
/* tcp_rtt_sa is not 0 means this is a new sample. */
if (sa != 0) {
/*
* Update average estimator:
* new rtt = 7/8 old rtt + 1/8 Error
*/
/* m is now Error in estimate. */
m -= sa >> 3;
if ((sa += m) <= 0) {
/*
* Don't allow the smoothed average to be negative.
* We use 0 to denote reinitialization of the
* variables.
*/
sa = 1;
}
/*
* Update deviation estimator:
* new mdev = 3/4 old mdev + 1/4 (abs(Error) - old mdev)
*/
if (m < 0)
m = -m;
m -= sv >> 2;
sv += m;
} else {
/*
* This follows BSD's implementation. So the reinitialized
* RTO is 3 * m. We cannot go less than 2 because if the
* link is bandwidth dominated, doubling the window size
* during slow start means doubling the RTT. We want to be
* more conservative when we reinitialize our estimates. 3
* is just a convenient number.
*/
sa = m << 3;
sv = m << 1;
}
if (sv < TCP_SD_MIN) {
/*
* We do not know that if sa captures the delay ACK
* effect as in a long train of segments, a receiver
* does not delay its ACKs. So set the minimum of sv
* to be TCP_SD_MIN, which is default to 400 ms, twice
* of BSD DATO. That means the minimum of mean
* deviation is 100 ms.
*
*/
sv = TCP_SD_MIN;
}
/*
* RTO = average estimates (sa / 8) + 4 * deviation estimates (sv)
*
* Add tcp_rexmit_interval extra in case of extreme environment
* where the algorithm fails to work. The default value of
* tcp_rexmit_interval_extra should be 0.
*
* As we use a finer grained clock than BSD and update
* RTO for every ACKs, add in another .25 of RTT to the
* deviation of RTO to accomodate burstiness of 1/4 of
* window size.
*/
} else {
}
/* Now, we can reset tcp_timer_backoff to use the new RTO... */
tcp->tcp_timer_backoff = 0;
}
/*
* On a labeled system we have some protocols above TCP, such as RPC, which
* appear to assume that every mblk in a chain has a db_credp.
*/
static void
{
}
}
{
/* Learn the latest rwnd information that we sent to the other side. */
<< tcp->tcp_rcv_ws;
/* This is peer's calculated send window (our receive window). */
/*
* Increase the receive window to max. But we need to do receiver
* SWS avoidance. This means that we need to check the increase of
* of receive window is at least 1 MSS.
*/
/*
* If the window that the other side knows is less than max
* deferred acks segments, send an update immediately.
*/
ret = TH_ACK_NEEDED;
}
}
return (ret);
}
/*
* Handle a packet that has been reclassified by TCP.
* This function drops the ref on connp that the caller had.
*/
void
{
if (connp->conn_incoming_ifindex != 0 &&
return;
}
} else {
}
/* Note that mp is NULL */
return;
}
}
if (IPCL_IS_TCP(connp)) {
/*
* do not drain, certain use cases can blow
* the stack
*/
} else {
/* Not TCP; must be SOCK_RAW, IPPROTO_TCP */
ira);
}
}
/* ARGSUSED */
static void
{
return;
}
return;
}
if (canputnext(q)) {
/* Not flow-controlled, open rwnd */
/*
* Send back a window update immediately if TCP is above
* ESTABLISHED state and the increase of the rcv window
* that the other side knows is at least 1 MSS after flow
* control is lifted.
*/
}
}
}
/*
* The read side service routine is called mostly when we get back-enabled as a
* result of flow control relief. Since we don't actually queue anything in
* TCP, we have no data to send out of here. What we do is clear the receive
* window, and send out a window update.
*/
void
{
/* No code does a putq on the read side */
/*
* If tcp->tcp_rsrv_mp == NULL, it means that tcp_rsrv() has already
* been run. So just return.
*/
return;
}
}
/* At minimum we need 8 bytes in the TCP header for the lookup */
#define ICMP_MIN_TCP_HDR 8
/*
* tcp_icmp_input is called as conn_recvicmp to process ICMP error messages
* passed up by IP. The message is always received on the correct tcp_t.
* Assumes that IP has pulled up everything up to and including the ICMP header.
*/
/* ARGSUSED2 */
void
{
int iph_hdr_length;
/* Assume IP provides aligned packets */
/*
* Verify IP version. Anything other than IPv4 or IPv6 packet is sent
* upstream. ICMPv6 is handled in tcp_icmp_error_ipv6.
*/
return;
}
/* Skip past the outer IP and ICMP headers */
/*
* If we don't have the correct outer IP header length
* or if we don't have a complete inner IP header
* drop it.
*/
if (iph_hdr_length < sizeof (ipha_t) ||
return;
}
/* Skip past the inner IP and find the ULP header */
/*
* If we don't have the correct inner IP header length or if the ULP
* is not IPPROTO_TCP or if we don't have at least ICMP_MIN_TCP_HDR
* bytes of TCP header, drop it.
*/
if (iph_hdr_length < sizeof (ipha_t) ||
goto noticmpv4;
}
switch (icmph->icmph_type) {
case ICMP_DEST_UNREACHABLE:
switch (icmph->icmph_code) {
/*
* Update Path MTU, then try to send something out.
*/
break;
case ICMP_PORT_UNREACHABLE:
case TCPS_SYN_SENT:
case TCPS_SYN_RCVD:
/*
* ICMP can snipe away incipient
* TCP connections as long as
* seq number is same as initial
* send seq number.
*/
(void) tcp_clean_death(tcp,
}
break;
}
break;
case ICMP_HOST_UNREACHABLE:
case ICMP_NET_UNREACHABLE:
/* Record the error in case we finally time out. */
else
/*
* Ditch the half-open connection if we
* suspect a SYN attack is under way.
*/
(void) tcp_clean_death(tcp,
}
}
break;
default:
break;
}
break;
case ICMP_SOURCE_QUENCH: {
/*
* use a global boolean to control
* whether TCP should respond to ICMP_SOURCE_QUENCH.
* The default is false.
*/
if (tcp_icmp_source_quench) {
/*
* Reduce the sending rate as if we got a
* retransmit timeout
*/
tcp->tcp_cwnd_cnt = 0;
}
break;
}
}
}
/*
* tcp_icmp_error_ipv6 is called from tcp_icmp_input to process ICMPv6
* error messages passed up by IP.
* Assumes that IP has pulled up all the extension headers as well
* as the ICMPv6 header.
*/
static void
{
/*
* Verify that we have a complete IP header.
*/
/*
* Verify if we have a complete ICMP and inner IP header.
*/
return;
}
goto noticmpv6;
/*
* Validate inner header. If the ULP is not IPPROTO_TCP or if we don't
* have at least ICMP_MIN_TCP_HDR bytes of TCP header drop the
* packet.
*/
if ((*nexthdrp != IPPROTO_TCP) ||
goto noticmpv6;
}
switch (icmp6->icmp6_type) {
case ICMP6_PACKET_TOO_BIG:
/*
* Update Path MTU, then try to send something out.
*/
break;
case ICMP6_DST_UNREACH:
switch (icmp6->icmp6_code) {
case ICMP6_DST_UNREACH_NOPORT:
}
break;
case ICMP6_DST_UNREACH_ADMIN:
case ICMP6_DST_UNREACH_ADDR:
/* Record the error in case we finally time out. */
/*
* Ditch the half-open connection if we
* suspect a SYN attack is under way.
*/
(void) tcp_clean_death(tcp,
}
}
break;
default:
break;
}
break;
case ICMP6_PARAM_PROB:
/* If this corresponds to an ICMP_PROTOCOL_UNREACHABLE */
}
break;
}
break;
case ICMP6_TIME_EXCEEDED:
default:
break;
}
}
/*
* CALLED OUTSIDE OF SQUEUE! It can not follow any pointers that tcp might
* change. But it can refer to fields like tcp_suna and tcp_snxt.
*
* Function tcp_verifyicmp is called as conn_verifyicmp to verify the ICMP
* error messages received by IP. The message is always received on the correct
* tcp_t.
*/
/* ARGSUSED */
{
/*
* TCP sequence number contained in payload of the ICMP error message
* should be within the range SND.UNA <= SEG.SEQ < SND.NXT. Otherwise,
* the message is either a stale ICMP error, or an attack from the
* network. Fail the verification.
*/
return (B_FALSE);
/* For "too big" we also check the ignore flag */
return (B_FALSE);
} else {
return (B_FALSE);
}
return (B_TRUE);
}