1 // SPDX-License-Identifier: GPL-2.0-only
2 /******************************************************************************
3 *******************************************************************************
4 **
5 ** Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved.
6 ** Copyright (C) 2004-2008 Red Hat, Inc. All rights reserved.
7 **
8 **
9 *******************************************************************************
10 ******************************************************************************/
11
12 /*
13 * midcomms.c
14 *
15 * This is the appallingly named "mid-level" comms layer.
16 *
17 * Its purpose is to take packets from the "real" comms layer,
18 * split them up into packets and pass them to the interested
19 * part of the locking mechanism.
20 *
21 * It also takes messages from the locking layer, formats them
22 * into packets and sends them to the comms layer.
23 */
24
25 #include <asm/unaligned.h>
26
27 #include "dlm_internal.h"
28 #include "lowcomms.h"
29 #include "config.h"
30 #include "lock.h"
31 #include "midcomms.h"
32
33 /*
34 * Called from the low-level comms layer to process a buffer of
35 * commands.
36 */
37
dlm_process_incoming_buffer(int nodeid,unsigned char * buf,int len)38 int dlm_process_incoming_buffer(int nodeid, unsigned char *buf, int len)
39 {
40 const unsigned char *ptr = buf;
41 const struct dlm_header *hd;
42 uint16_t msglen;
43 int ret = 0;
44
45 while (len >= sizeof(struct dlm_header)) {
46 hd = (struct dlm_header *)ptr;
47
48 /* no message should be more than this otherwise we
49 * cannot deliver this message to upper layers
50 */
51 msglen = get_unaligned_le16(&hd->h_length);
52 if (msglen > DEFAULT_BUFFER_SIZE ||
53 msglen < sizeof(struct dlm_header)) {
54 log_print("received invalid length header: %u from node %d, will abort message parsing",
55 msglen, nodeid);
56 return -EBADMSG;
57 }
58
59 /* caller will take care that leftover
60 * will be parsed next call with more data
61 */
62 if (msglen > len)
63 break;
64
65 switch (hd->h_cmd) {
66 case DLM_MSG:
67 if (msglen < sizeof(struct dlm_message)) {
68 log_print("dlm msg too small: %u, will skip this message",
69 msglen);
70 goto skip;
71 }
72
73 break;
74 case DLM_RCOM:
75 if (msglen < sizeof(struct dlm_rcom)) {
76 log_print("dlm rcom msg too small: %u, will skip this message",
77 msglen);
78 goto skip;
79 }
80
81 break;
82 default:
83 log_print("unsupported h_cmd received: %u, will skip this message",
84 hd->h_cmd);
85 goto skip;
86 }
87
88 /* for aligned memory access, we just copy current message
89 * to begin of the buffer which contains already parsed buffer
90 * data and should provide align access for upper layers
91 * because the start address of the buffer has a aligned
92 * address. This memmove can be removed when the upperlayer
93 * is capable of unaligned memory access.
94 */
95 memmove(buf, ptr, msglen);
96 dlm_receive_buffer((union dlm_packet *)buf, nodeid);
97
98 skip:
99 ret += msglen;
100 len -= msglen;
101 ptr += msglen;
102 }
103
104 return ret;
105 }
106
107