1 // SPDX-License-Identifier: GPL-2.0-or-later
3 * DECnet An implementation of the DECnet protocol suite for the LINUX
4 * operating system. DECnet is implemented using the BSD Socket
5 * interface as the means of communication with the user level.
7 * DECnet Network Services Protocol (Input)
9 * Author: Eduardo Marcelo Serrat <emserrat@geocities.com>
13 * Steve Whitehouse: Split into dn_nsp_in.c and dn_nsp_out.c from
15 * Steve Whitehouse: Updated to work with my new routing architecture.
16 * Steve Whitehouse: Add changes from Eduardo Serrat's patches.
17 * Steve Whitehouse: Put all ack handling code in a common routine.
18 * Steve Whitehouse: Put other common bits into dn_nsp_rx()
19 * Steve Whitehouse: More checks on skb->len to catch bogus packets
20 * Fixed various race conditions and possible nasties.
21 * Steve Whitehouse: Now handles returned conninit frames.
22 * David S. Miller: New socket locking
23 * Steve Whitehouse: Fixed lockup when socket filtering was enabled.
24 * Paul Koning: Fix to push CC sockets into RUN when acks are
27 * Patrick Caulfield: Checking conninits for correctness & sending of error
29 * Steve Whitehouse: Added backlog congestion level return codes.
31 * Steve Whitehouse: Added flow control support (outbound)
32 * Steve Whitehouse: Prepare for nonlinear skbs
35 /******************************************************************************
36 (c) 1995-1998 E.M. Serrat emserrat@geocities.com
38 *******************************************************************************/
40 #include <linux/errno.h>
41 #include <linux/filter.h>
42 #include <linux/types.h>
43 #include <linux/socket.h>
45 #include <linux/kernel.h>
46 #include <linux/timer.h>
47 #include <linux/string.h>
48 #include <linux/sockios.h>
49 #include <linux/net.h>
50 #include <linux/netdevice.h>
51 #include <linux/inet.h>
52 #include <linux/route.h>
53 #include <linux/slab.h>
55 #include <net/tcp_states.h>
56 #include <linux/fcntl.h>
58 #include <linux/termios.h>
59 #include <linux/interrupt.h>
60 #include <linux/proc_fs.h>
61 #include <linux/stat.h>
62 #include <linux/init.h>
63 #include <linux/poll.h>
64 #include <linux/netfilter_decnet.h>
65 #include <net/neighbour.h>
68 #include <net/dn_nsp.h>
69 #include <net/dn_dev.h>
70 #include <net/dn_route.h>
72 extern int decnet_log_martians;
74 static void dn_log_martian(struct sk_buff *skb, const char *msg)
76 if (decnet_log_martians) {
77 char *devname = skb->dev ? skb->dev->name : "???";
78 struct dn_skb_cb *cb = DN_SKB_CB(skb);
79 net_info_ratelimited("DECnet: Martian packet (%s) dev=%s src=0x%04hx dst=0x%04hx srcport=0x%04hx dstport=0x%04hx\n",
83 le16_to_cpu(cb->src_port),
84 le16_to_cpu(cb->dst_port));
89 * For this function we've flipped the cross-subchannel bit
90 * if the message is an otherdata or linkservice message. Thus
91 * we can use it to work out what to update.
93 static void dn_ack(struct sock *sk, struct sk_buff *skb, unsigned short ack)
95 struct dn_scp *scp = DN_SK(sk);
96 unsigned short type = ((ack >> 12) & 0x0003);
100 case 0: /* ACK - Data */
101 if (dn_after(ack, scp->ackrcv_dat)) {
102 scp->ackrcv_dat = ack & 0x0fff;
103 wakeup |= dn_nsp_check_xmit_queue(sk, skb,
104 &scp->data_xmit_queue,
108 case 1: /* NAK - Data */
110 case 2: /* ACK - OtherData */
111 if (dn_after(ack, scp->ackrcv_oth)) {
112 scp->ackrcv_oth = ack & 0x0fff;
113 wakeup |= dn_nsp_check_xmit_queue(sk, skb,
114 &scp->other_xmit_queue,
118 case 3: /* NAK - OtherData */
122 if (wakeup && !sock_flag(sk, SOCK_DEAD))
123 sk->sk_state_change(sk);
127 * This function is a universal ack processor.
129 static int dn_process_ack(struct sock *sk, struct sk_buff *skb, int oth)
131 __le16 *ptr = (__le16 *)skb->data;
138 if ((ack = le16_to_cpu(*ptr)) & 0x8000) {
142 if ((ack & 0x4000) == 0) {
145 dn_ack(sk, skb, ack);
152 if ((ack = le16_to_cpu(*ptr)) & 0x8000) {
155 if ((ack & 0x4000) == 0) {
158 dn_ack(sk, skb, ack);
167 * dn_check_idf - Check an image data field format is correct.
168 * @pptr: Pointer to pointer to image data
169 * @len: Pointer to length of image data
170 * @max: The maximum allowed length of the data in the image data field
171 * @follow_on: Check that this many bytes exist beyond the end of the image data
173 * Returns: 0 if ok, -1 on error
175 static inline int dn_check_idf(unsigned char **pptr, int *len, unsigned char max, unsigned char follow_on)
177 unsigned char *ptr = *pptr;
178 unsigned char flen = *ptr++;
183 if ((flen + follow_on) > *len)
192 * Table of reason codes to pass back to node which sent us a badly
193 * formed message, plus text messages for the log. A zero entry in
194 * the reason field means "don't reply" otherwise a disc init is sent with
195 * the specified reason code.
198 unsigned short reason;
201 { 0, "CI: Truncated message" },
202 { NSP_REASON_ID, "CI: Destination username error" },
203 { NSP_REASON_ID, "CI: Destination username type" },
204 { NSP_REASON_US, "CI: Source username error" },
205 { 0, "CI: Truncated at menuver" },
206 { 0, "CI: Truncated before access or user data" },
207 { NSP_REASON_IO, "CI: Access data format error" },
208 { NSP_REASON_IO, "CI: User data format error" }
212 * This function uses a slightly different lookup method
213 * to find its sockets, since it searches on object name/number
214 * rather than port numbers. Various tests are done to ensure that
215 * the incoming data is in the correct format before it is queued to
218 static struct sock *dn_find_listener(struct sk_buff *skb, unsigned short *reason)
220 struct dn_skb_cb *cb = DN_SKB_CB(skb);
221 struct nsp_conn_init_msg *msg = (struct nsp_conn_init_msg *)skb->data;
222 struct sockaddr_dn dstaddr;
223 struct sockaddr_dn srcaddr;
224 unsigned char type = 0;
230 unsigned char menuver;
232 memset(&dstaddr, 0, sizeof(struct sockaddr_dn));
233 memset(&srcaddr, 0, sizeof(struct sockaddr_dn));
236 * 1. Decode & remove message header
238 cb->src_port = msg->srcaddr;
239 cb->dst_port = msg->dstaddr;
240 cb->services = msg->services;
241 cb->info = msg->info;
242 cb->segsize = le16_to_cpu(msg->segsize);
244 if (!pskb_may_pull(skb, sizeof(*msg)))
247 skb_pull(skb, sizeof(*msg));
253 * 2. Check destination end username format
255 dstlen = dn_username2sockaddr(ptr, len, &dstaddr, &type);
268 * 3. Check source end username format
270 srclen = dn_username2sockaddr(ptr, len, &srcaddr, &type);
286 * 4. Check that optional data actually exists if menuver says it does
289 if ((menuver & (DN_MENUVER_ACC | DN_MENUVER_USR)) && (len < 1))
293 * 5. Check optional access data format
296 if (menuver & DN_MENUVER_ACC) {
297 if (dn_check_idf(&ptr, &len, 39, 1))
299 if (dn_check_idf(&ptr, &len, 39, 1))
301 if (dn_check_idf(&ptr, &len, 39, (menuver & DN_MENUVER_USR) ? 1 : 0))
306 * 6. Check optional user data format
309 if (menuver & DN_MENUVER_USR) {
310 if (dn_check_idf(&ptr, &len, 16, 0))
315 * 7. Look up socket based on destination end username
317 return dn_sklist_find_listener(&dstaddr);
319 dn_log_martian(skb, ci_err_table[err].text);
320 *reason = ci_err_table[err].reason;
325 static void dn_nsp_conn_init(struct sock *sk, struct sk_buff *skb)
327 if (sk_acceptq_is_full(sk)) {
332 sk_acceptq_added(sk);
333 skb_queue_tail(&sk->sk_receive_queue, skb);
334 sk->sk_state_change(sk);
337 static void dn_nsp_conn_conf(struct sock *sk, struct sk_buff *skb)
339 struct dn_skb_cb *cb = DN_SKB_CB(skb);
340 struct dn_scp *scp = DN_SK(sk);
347 cb->services = *ptr++;
349 cb->segsize = le16_to_cpu(*(__le16 *)ptr);
351 if ((scp->state == DN_CI) || (scp->state == DN_CD)) {
353 scp->addrrem = cb->src_port;
354 sk->sk_state = TCP_ESTABLISHED;
356 scp->services_rem = cb->services;
357 scp->info_rem = cb->info;
358 scp->segsize_rem = cb->segsize;
360 if ((scp->services_rem & NSP_FC_MASK) == NSP_FC_NONE)
361 scp->max_window = decnet_no_fc_max_cwnd;
364 u16 dlen = *skb->data;
365 if ((dlen <= 16) && (dlen <= skb->len)) {
366 scp->conndata_in.opt_optl = cpu_to_le16(dlen);
367 skb_copy_from_linear_data_offset(skb, 1,
368 scp->conndata_in.opt_data, dlen);
371 dn_nsp_send_link(sk, DN_NOCHANGE, 0);
372 if (!sock_flag(sk, SOCK_DEAD))
373 sk->sk_state_change(sk);
380 static void dn_nsp_conn_ack(struct sock *sk, struct sk_buff *skb)
382 struct dn_scp *scp = DN_SK(sk);
384 if (scp->state == DN_CI) {
392 static void dn_nsp_disc_init(struct sock *sk, struct sk_buff *skb)
394 struct dn_scp *scp = DN_SK(sk);
395 struct dn_skb_cb *cb = DN_SKB_CB(skb);
396 unsigned short reason;
401 reason = le16_to_cpu(*(__le16 *)skb->data);
404 scp->discdata_in.opt_status = cpu_to_le16(reason);
405 scp->discdata_in.opt_optl = 0;
406 memset(scp->discdata_in.opt_data, 0, 16);
409 u16 dlen = *skb->data;
410 if ((dlen <= 16) && (dlen <= skb->len)) {
411 scp->discdata_in.opt_optl = cpu_to_le16(dlen);
412 skb_copy_from_linear_data_offset(skb, 1, scp->discdata_in.opt_data, dlen);
416 scp->addrrem = cb->src_port;
417 sk->sk_state = TCP_CLOSE;
419 switch (scp->state) {
423 sk->sk_err = ECONNREFUSED;
426 sk->sk_shutdown |= SHUTDOWN_MASK;
434 if (!sock_flag(sk, SOCK_DEAD)) {
435 if (sk->sk_socket->state != SS_UNCONNECTED)
436 sk->sk_socket->state = SS_DISCONNECTING;
437 sk->sk_state_change(sk);
441 * It appears that its possible for remote machines to send disc
442 * init messages with no port identifier if we are in the CI and
443 * possibly also the CD state. Obviously we shouldn't reply with
444 * a message if we don't know what the end point is.
447 dn_nsp_send_disc(sk, NSP_DISCCONF, NSP_REASON_DC, GFP_ATOMIC);
449 scp->persist_fxn = dn_destroy_timer;
450 scp->persist = dn_nsp_persist(sk);
457 * disc_conf messages are also called no_resources or no_link
458 * messages depending upon the "reason" field.
460 static void dn_nsp_disc_conf(struct sock *sk, struct sk_buff *skb)
462 struct dn_scp *scp = DN_SK(sk);
463 unsigned short reason;
468 reason = le16_to_cpu(*(__le16 *)skb->data);
470 sk->sk_state = TCP_CLOSE;
472 switch (scp->state) {
477 if (reason == NSP_REASON_DC)
479 if (reason == NSP_REASON_NL)
486 sk->sk_shutdown |= SHUTDOWN_MASK;
492 if (!sock_flag(sk, SOCK_DEAD)) {
493 if (sk->sk_socket->state != SS_UNCONNECTED)
494 sk->sk_socket->state = SS_DISCONNECTING;
495 sk->sk_state_change(sk);
498 scp->persist_fxn = dn_destroy_timer;
499 scp->persist = dn_nsp_persist(sk);
505 static void dn_nsp_linkservice(struct sock *sk, struct sk_buff *skb)
507 struct dn_scp *scp = DN_SK(sk);
508 unsigned short segnum;
509 unsigned char lsflags;
512 char *ptr = skb->data;
513 unsigned char fctype = scp->services_rem & NSP_FC_MASK;
518 segnum = le16_to_cpu(*(__le16 *)ptr);
520 lsflags = *(unsigned char *)ptr++;
524 * Here we ignore erroneous packets which should really
525 * should cause a connection abort. It is not critical
531 if (seq_next(scp->numoth_rcv, segnum)) {
532 seq_add(&scp->numoth_rcv, 1);
533 switch(lsflags & 0x04) { /* FCVAL INT */
534 case 0x00: /* Normal Request */
535 switch(lsflags & 0x03) { /* FCVAL MOD */
536 case 0x00: /* Request count */
538 unsigned char p_fcval = -fcval;
539 if ((scp->flowrem_dat > p_fcval) &&
540 (fctype == NSP_FC_SCMC)) {
541 scp->flowrem_dat -= p_fcval;
543 } else if (fcval > 0) {
544 scp->flowrem_dat += fcval;
548 case 0x01: /* Stop outgoing data */
549 scp->flowrem_sw = DN_DONTSEND;
551 case 0x02: /* Ok to start again */
552 scp->flowrem_sw = DN_SEND;
557 case 0x04: /* Interrupt Request */
559 scp->flowrem_oth += fcval;
564 if (wake_up && !sock_flag(sk, SOCK_DEAD))
565 sk->sk_state_change(sk);
568 dn_nsp_send_oth_ack(sk);
575 * Copy of sock_queue_rcv_skb (from sock.h) without
576 * bh_lock_sock() (its already held when this is called) which
577 * also allows data and other data to be queued to a socket.
579 static __inline__ int dn_queue_skb(struct sock *sk, struct sk_buff *skb, int sig, struct sk_buff_head *queue)
583 /* Cast skb->rcvbuf to unsigned... It's pointless, but reduces
584 number of warnings when compiling with -W --ANK
586 if (atomic_read(&sk->sk_rmem_alloc) + skb->truesize >=
587 (unsigned int)sk->sk_rcvbuf) {
592 err = sk_filter(sk, skb);
596 skb_set_owner_r(skb, sk);
597 skb_queue_tail(queue, skb);
599 if (!sock_flag(sk, SOCK_DEAD))
600 sk->sk_data_ready(sk);
605 static void dn_nsp_otherdata(struct sock *sk, struct sk_buff *skb)
607 struct dn_scp *scp = DN_SK(sk);
608 unsigned short segnum;
609 struct dn_skb_cb *cb = DN_SKB_CB(skb);
615 cb->segnum = segnum = le16_to_cpu(*(__le16 *)skb->data);
618 if (seq_next(scp->numoth_rcv, segnum)) {
620 if (dn_queue_skb(sk, skb, SIGURG, &scp->other_receive_queue) == 0) {
621 seq_add(&scp->numoth_rcv, 1);
622 scp->other_report = 0;
627 dn_nsp_send_oth_ack(sk);
633 static void dn_nsp_data(struct sock *sk, struct sk_buff *skb)
636 unsigned short segnum;
637 struct dn_skb_cb *cb = DN_SKB_CB(skb);
638 struct dn_scp *scp = DN_SK(sk);
643 cb->segnum = segnum = le16_to_cpu(*(__le16 *)skb->data);
646 if (seq_next(scp->numdat_rcv, segnum)) {
647 if (dn_queue_skb(sk, skb, SIGIO, &sk->sk_receive_queue) == 0) {
648 seq_add(&scp->numdat_rcv, 1);
652 if ((scp->flowloc_sw == DN_SEND) && dn_congested(sk)) {
653 scp->flowloc_sw = DN_DONTSEND;
654 dn_nsp_send_link(sk, DN_DONTSEND, 0);
658 dn_nsp_send_data_ack(sk);
665 * If one of our conninit messages is returned, this function
666 * deals with it. It puts the socket into the NO_COMMUNICATION
669 static void dn_returned_conn_init(struct sock *sk, struct sk_buff *skb)
671 struct dn_scp *scp = DN_SK(sk);
673 if (scp->state == DN_CI) {
675 sk->sk_state = TCP_CLOSE;
676 if (!sock_flag(sk, SOCK_DEAD))
677 sk->sk_state_change(sk);
683 static int dn_nsp_no_socket(struct sk_buff *skb, unsigned short reason)
685 struct dn_skb_cb *cb = DN_SKB_CB(skb);
686 int ret = NET_RX_DROP;
688 /* Must not reply to returned packets */
689 if (cb->rt_flags & DN_RT_F_RTS)
692 if ((reason != NSP_REASON_OK) && ((cb->nsp_flags & 0x0c) == 0x08)) {
693 switch (cb->nsp_flags & 0x70) {
695 case 0x60: /* (Retransmitted) Connect Init */
696 dn_nsp_return_disc(skb, NSP_DISCINIT, reason);
697 ret = NET_RX_SUCCESS;
699 case 0x20: /* Connect Confirm */
700 dn_nsp_return_disc(skb, NSP_DISCCONF, reason);
701 ret = NET_RX_SUCCESS;
711 static int dn_nsp_rx_packet(struct net *net, struct sock *sk2,
714 struct dn_skb_cb *cb = DN_SKB_CB(skb);
715 struct sock *sk = NULL;
716 unsigned char *ptr = (unsigned char *)skb->data;
717 unsigned short reason = NSP_REASON_NL;
719 if (!pskb_may_pull(skb, 2))
722 skb_reset_transport_header(skb);
723 cb->nsp_flags = *ptr++;
725 if (decnet_debug_level & 2)
726 printk(KERN_DEBUG "dn_nsp_rx: Message type 0x%02x\n", (int)cb->nsp_flags);
728 if (cb->nsp_flags & 0x83)
732 * Filter out conninits and useless packet types
734 if ((cb->nsp_flags & 0x0c) == 0x08) {
735 switch (cb->nsp_flags & 0x70) {
737 case 0x70: /* Reserved */
738 case 0x50: /* Reserved, Phase II node init */
742 if (unlikely(cb->rt_flags & DN_RT_F_RTS))
744 sk = dn_find_listener(skb, &reason);
749 if (!pskb_may_pull(skb, 3))
753 * Grab the destination address.
755 cb->dst_port = *(__le16 *)ptr;
760 * If not a connack, grab the source address too.
762 if (pskb_may_pull(skb, 5)) {
763 cb->src_port = *(__le16 *)ptr;
769 * Returned packets...
770 * Swap src & dst and look up in the normal way.
772 if (unlikely(cb->rt_flags & DN_RT_F_RTS)) {
773 swap(cb->dst_port, cb->src_port);
774 swap(cb->dst, cb->src);
778 * Find the socket to which this skb is destined.
780 sk = dn_find_by_skb(skb);
783 struct dn_scp *scp = DN_SK(sk);
786 scp->nsp_rxtshift = 0;
789 * We linearize everything except data segments here.
791 if (cb->nsp_flags & ~0x60) {
792 if (unlikely(skb_linearize(skb)))
796 return sk_receive_skb(sk, skb, 0);
799 return dn_nsp_no_socket(skb, reason);
806 int dn_nsp_rx(struct sk_buff *skb)
808 return NF_HOOK(NFPROTO_DECNET, NF_DN_LOCAL_IN,
809 &init_net, NULL, skb, skb->dev, NULL,
814 * This is the main receive routine for sockets. It is called
815 * from the above when the socket is not busy, and also from
816 * sock_release() when there is a backlog queued up.
818 int dn_nsp_backlog_rcv(struct sock *sk, struct sk_buff *skb)
820 struct dn_scp *scp = DN_SK(sk);
821 struct dn_skb_cb *cb = DN_SKB_CB(skb);
823 if (cb->rt_flags & DN_RT_F_RTS) {
824 if (cb->nsp_flags == 0x18 || cb->nsp_flags == 0x68)
825 dn_returned_conn_init(sk, skb);
828 return NET_RX_SUCCESS;
834 if ((cb->nsp_flags & 0x0c) == 0x08) {
835 switch (cb->nsp_flags & 0x70) {
838 dn_nsp_conn_init(sk, skb);
841 dn_nsp_conn_conf(sk, skb);
844 dn_nsp_disc_init(sk, skb);
847 dn_nsp_disc_conf(sk, skb);
851 } else if (cb->nsp_flags == 0x24) {
853 * Special for connacks, 'cos they don't have
854 * ack data or ack otherdata info.
856 dn_nsp_conn_ack(sk, skb);
860 /* both data and ack frames can kick a CC socket into RUN */
861 if ((scp->state == DN_CC) && !sock_flag(sk, SOCK_DEAD)) {
863 sk->sk_state = TCP_ESTABLISHED;
864 sk->sk_state_change(sk);
867 if ((cb->nsp_flags & 0x1c) == 0)
869 if (cb->nsp_flags == 0x04)
873 * Read out ack data here, this applies equally
874 * to data, other data, link service and both
875 * ack data and ack otherdata.
877 dn_process_ack(sk, skb, other);
880 * If we've some sort of data here then call a
881 * suitable routine for dealing with it, otherwise
882 * the packet is an ack and can be discarded.
884 if ((cb->nsp_flags & 0x0c) == 0) {
886 if (scp->state != DN_RUN)
889 switch (cb->nsp_flags) {
891 dn_nsp_linkservice(sk, skb);
894 dn_nsp_otherdata(sk, skb);
897 dn_nsp_data(sk, skb);
900 } else { /* Ack, chuck it out here */
906 return NET_RX_SUCCESS;