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      1 /*	$NetBSD: dispatch.c,v 1.13 2026/04/08 18:58:40 christos Exp $	*/
      2 /* $OpenBSD: dispatch.c,v 1.35 2026/03/03 09:57:25 dtucker Exp $ */
      3 
      4 /*
      5  * Copyright (c) 2000 Markus Friedl.  All rights reserved.
      6  *
      7  * Redistribution and use in source and binary forms, with or without
      8  * modification, are permitted provided that the following conditions
      9  * are met:
     10  * 1. Redistributions of source code must retain the above copyright
     11  *    notice, this list of conditions and the following disclaimer.
     12  * 2. Redistributions in binary form must reproduce the above copyright
     13  *    notice, this list of conditions and the following disclaimer in the
     14  *    documentation and/or other materials provided with the distribution.
     15  *
     16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
     17  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
     18  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
     19  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
     20  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
     21  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     22  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     23  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     24  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
     25  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     26  */
     27 
     28 #include "includes.h"
     29 __RCSID("$NetBSD: dispatch.c,v 1.13 2026/04/08 18:58:40 christos Exp $");
     30 #include <sys/types.h>
     31 
     32 #include <signal.h>
     33 #include <stdarg.h>
     34 
     35 #include "ssh2.h"
     36 #include "log.h"
     37 #include "dispatch.h"
     38 #include "packet.h"
     39 #include "ssherr.h"
     40 
     41 int
     42 dispatch_protocol_error(int type, uint32_t seq, struct ssh *ssh)
     43 {
     44 	int r;
     45 
     46 	logit_f("type %d seq %u", type, seq);
     47 	if ((r = sshpkt_start(ssh, SSH2_MSG_UNIMPLEMENTED)) != 0 ||
     48 	    (r = sshpkt_put_u32(ssh, seq)) != 0 ||
     49 	    (r = sshpkt_send(ssh)) != 0 ||
     50 	    (r = ssh_packet_write_wait(ssh)) < 0)
     51 		sshpkt_fatal(ssh, r, "%s", __func__);
     52 	return 0;
     53 }
     54 
     55 int
     56 dispatch_protocol_ignore(int type, uint32_t seq, struct ssh *ssh)
     57 {
     58 	logit_f("type %d seq %u", type, seq);
     59 	return 0;
     60 }
     61 
     62 void
     63 ssh_dispatch_init(struct ssh *ssh, dispatch_fn *dflt)
     64 {
     65 	u_int i;
     66 	for (i = 0; i < DISPATCH_MAX; i++)
     67 		ssh->dispatch[i] = dflt;
     68 }
     69 
     70 void
     71 ssh_dispatch_range(struct ssh *ssh, u_int from, u_int to, dispatch_fn *fn)
     72 {
     73 	u_int i;
     74 
     75 	for (i = from; i <= to; i++) {
     76 		if (i >= DISPATCH_MAX)
     77 			break;
     78 		ssh->dispatch[i] = fn;
     79 	}
     80 }
     81 
     82 void
     83 ssh_dispatch_set(struct ssh *ssh, int type, dispatch_fn *fn)
     84 {
     85 	ssh->dispatch[type] = fn;
     86 }
     87 
     88 int
     89 ssh_dispatch_run(struct ssh *ssh, int mode, volatile sig_atomic_t *done)
     90 {
     91 	int r;
     92 	u_char type;
     93 	uint32_t seqnr;
     94 
     95 	for (;;) {
     96 		if (mode == DISPATCH_BLOCK) {
     97 			r = ssh_packet_read_seqnr(ssh, &type, &seqnr);
     98 			if (r != 0)
     99 				return r;
    100 		} else {
    101 			r = ssh_packet_read_poll_seqnr(ssh, &type, &seqnr);
    102 			if (r != 0)
    103 				return r;
    104 			if (type == SSH_MSG_NONE)
    105 				return 0;
    106 		}
    107 		if (type > 0 && type < DISPATCH_MAX &&
    108 		    ssh->dispatch[type] != NULL) {
    109 			if (ssh->dispatch_skip_packets) {
    110 				debug2("skipped packet (type %u)", type);
    111 				ssh->dispatch_skip_packets--;
    112 				continue;
    113 			}
    114 			r = (*ssh->dispatch[type])(type, seqnr, ssh);
    115 			if (r != 0)
    116 				return r;
    117 		} else {
    118 			r = sshpkt_disconnect(ssh,
    119 			    "protocol error: rcvd type %d", type);
    120 			if (r != 0)
    121 				return r;
    122 			return SSH_ERR_DISCONNECTED;
    123 		}
    124 		if (done != NULL && *done)
    125 			return 0;
    126 	}
    127 }
    128 
    129 void
    130 ssh_dispatch_run_fatal(struct ssh *ssh, int mode, volatile sig_atomic_t *done)
    131 {
    132 	int r;
    133 
    134 	if ((r = ssh_dispatch_run(ssh, mode, done)) != 0)
    135 		sshpkt_fatal(ssh, r, "%s", __func__);
    136 }
    137