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 log_print("received invalid length header: %u, will abort message parsing",
54 msglen);
55 return -EBADMSG;
56 }
57
58 /* caller will take care that leftover
59 * will be parsed next call with more data
60 */
61 if (msglen > len)
62 break;
63
64 switch (hd->h_cmd) {
65 case DLM_MSG:
66 if (msglen < sizeof(struct dlm_message)) {
67 log_print("dlm msg too small: %u, will skip this message",
68 msglen);
69 goto skip;
70 }
71
72 break;
73 case DLM_RCOM:
74 if (msglen < sizeof(struct dlm_rcom)) {
75 log_print("dlm rcom msg too small: %u, will skip this message",
76 msglen);
77 goto skip;
78 }
79
80 break;
81 default:
82 log_print("unsupported h_cmd received: %u, will skip this message",
83 hd->h_cmd);
84 goto skip;
85 }
86
87 /* for aligned memory access, we just copy current message
88 * to begin of the buffer which contains already parsed buffer
89 * data and should provide align access for upper layers
90 * because the start address of the buffer has a aligned
91 * address. This memmove can be removed when the upperlayer
92 * is capable of unaligned memory access.
93 */
94 memmove(buf, ptr, msglen);
95 dlm_receive_buffer((union dlm_packet *)buf, nodeid);
96
97 skip:
98 ret += msglen;
99 len -= msglen;
100 ptr += msglen;
101 }
102
103 return ret;
104 }
105
106