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2522fe45 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
e7fd4179 DT |
2 | /****************************************************************************** |
3 | ******************************************************************************* | |
4 | ** | |
5 | ** Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved. | |
e7847d35 | 6 | ** Copyright (C) 2004-2008 Red Hat, Inc. All rights reserved. |
e7fd4179 | 7 | ** |
e7fd4179 DT |
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 "dlm_internal.h" | |
26 | #include "lowcomms.h" | |
27 | #include "config.h" | |
e7fd4179 DT |
28 | #include "lock.h" |
29 | #include "midcomms.h" | |
30 | ||
31 | ||
32 | static void copy_from_cb(void *dst, const void *base, unsigned offset, | |
33 | unsigned len, unsigned limit) | |
34 | { | |
35 | unsigned copy = len; | |
36 | ||
37 | if ((copy + offset) > limit) | |
38 | copy = limit - offset; | |
39 | memcpy(dst, base + offset, copy); | |
40 | len -= copy; | |
41 | if (len) | |
42 | memcpy(dst + copy, base, len); | |
43 | } | |
44 | ||
45 | /* | |
46 | * Called from the low-level comms layer to process a buffer of | |
47 | * commands. | |
48 | * | |
49 | * Only complete messages are processed here, any "spare" bytes from | |
50 | * the end of a buffer are saved and tacked onto the front of the next | |
51 | * message that comes in. I doubt this will happen very often but we | |
52 | * need to be able to cope with it and I don't want the task to be waiting | |
53 | * for packets to come in when there is useful work to be done. | |
54 | */ | |
55 | ||
56 | int dlm_process_incoming_buffer(int nodeid, const void *base, | |
57 | unsigned offset, unsigned len, unsigned limit) | |
58 | { | |
e7847d35 FDN |
59 | union { |
60 | unsigned char __buf[DLM_INBUF_LEN]; | |
61 | /* this is to force proper alignment on some arches */ | |
eef7d739 | 62 | union dlm_packet p; |
e7847d35 | 63 | } __tmp; |
eef7d739 | 64 | union dlm_packet *p = &__tmp.p; |
e7fd4179 DT |
65 | int ret = 0; |
66 | int err = 0; | |
67 | uint16_t msglen; | |
68 | uint32_t lockspace; | |
69 | ||
70 | while (len > sizeof(struct dlm_header)) { | |
71 | ||
72 | /* Copy just the header to check the total length. The | |
73 | message may wrap around the end of the buffer back to the | |
74 | start, so we need to use a temp buffer and copy_from_cb. */ | |
75 | ||
eef7d739 | 76 | copy_from_cb(p, base, offset, sizeof(struct dlm_header), |
e7fd4179 DT |
77 | limit); |
78 | ||
eef7d739 AV |
79 | msglen = le16_to_cpu(p->header.h_length); |
80 | lockspace = p->header.h_lockspace; | |
e7fd4179 DT |
81 | |
82 | err = -EINVAL; | |
83 | if (msglen < sizeof(struct dlm_header)) | |
84 | break; | |
eef7d739 AV |
85 | if (p->header.h_cmd == DLM_MSG) { |
86 | if (msglen < sizeof(struct dlm_message)) | |
87 | break; | |
88 | } else { | |
89 | if (msglen < sizeof(struct dlm_rcom)) | |
90 | break; | |
91 | } | |
e7fd4179 | 92 | err = -E2BIG; |
68c817a1 | 93 | if (msglen > dlm_config.ci_buffer_size) { |
e7fd4179 DT |
94 | log_print("message size %d from %d too big, buf len %d", |
95 | msglen, nodeid, len); | |
96 | break; | |
97 | } | |
98 | err = 0; | |
99 | ||
100 | /* If only part of the full message is contained in this | |
101 | buffer, then do nothing and wait for lowcomms to call | |
102 | us again later with more data. We return 0 meaning | |
103 | we've consumed none of the input buffer. */ | |
104 | ||
105 | if (msglen > len) | |
106 | break; | |
107 | ||
108 | /* Allocate a larger temp buffer if the full message won't fit | |
109 | in the buffer on the stack (which should work for most | |
110 | ordinary messages). */ | |
111 | ||
eef7d739 | 112 | if (msglen > sizeof(__tmp) && p == &__tmp.p) { |
d6d7b702 | 113 | p = kmalloc(dlm_config.ci_buffer_size, GFP_NOFS); |
eef7d739 | 114 | if (p == NULL) |
e7fd4179 DT |
115 | return ret; |
116 | } | |
117 | ||
eef7d739 | 118 | copy_from_cb(p, base, offset, msglen, limit); |
e7fd4179 | 119 | |
eef7d739 | 120 | BUG_ON(lockspace != p->header.h_lockspace); |
e7fd4179 DT |
121 | |
122 | ret += msglen; | |
123 | offset += msglen; | |
124 | offset &= (limit - 1); | |
125 | len -= msglen; | |
126 | ||
eef7d739 | 127 | dlm_receive_buffer(p, nodeid); |
e7fd4179 DT |
128 | } |
129 | ||
eef7d739 AV |
130 | if (p != &__tmp.p) |
131 | kfree(p); | |
e7fd4179 DT |
132 | |
133 | return err ? err : ret; | |
134 | } | |
135 |