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9108f8d9 | 1 | /* $OpenBSD: buffer.c,v 1.31 2006/08/03 03:34:41 deraadt Exp $ */ |
3c0ef626 | 2 | /* |
3 | * Author: Tatu Ylonen <ylo@cs.hut.fi> | |
4 | * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland | |
5 | * All rights reserved | |
6 | * Functions for manipulating fifo buffers (that can grow if needed). | |
7 | * | |
8 | * As far as I am concerned, the code I have written for this software | |
9 | * can be used freely for any purpose. Any derived versions of this | |
10 | * software must be clearly marked as such, and if the derived work is | |
11 | * incompatible with the protocol description in the RFC file, it must be | |
12 | * called by a name other than "ssh" or "Secure Shell". | |
13 | */ | |
14 | ||
15 | #include "includes.h" | |
9108f8d9 | 16 | |
17 | #include <sys/param.h> | |
18 | ||
19 | #include <stdio.h> | |
20 | #include <string.h> | |
21 | #include <stdarg.h> | |
3c0ef626 | 22 | |
23 | #include "xmalloc.h" | |
24 | #include "buffer.h" | |
25 | #include "log.h" | |
26 | ||
9108f8d9 | 27 | #define BUFFER_MAX_CHUNK 0x100000 |
28 | #define BUFFER_MAX_LEN 0xa00000 | |
bed7ee6f | 29 | /* try increasing to 256k in hpnxfers */ |
30 | #define BUFFER_ALLOCSZ 0x008000 /* 32k */ | |
31 | #define BUFFER_ALLOCSZ_HPN 0x040000 /* 256k */ | |
9108f8d9 | 32 | |
3c0ef626 | 33 | /* Initializes the buffer structure. */ |
34 | ||
35 | void | |
36 | buffer_init(Buffer *buffer) | |
37 | { | |
b51b59a5 | 38 | const u_int len = 4096; |
39 | ||
40 | buffer->alloc = 0; | |
41 | buffer->buf = xmalloc(len); | |
42 | buffer->alloc = len; | |
3c0ef626 | 43 | buffer->offset = 0; |
44 | buffer->end = 0; | |
45 | } | |
46 | ||
bed7ee6f | 47 | |
3c0ef626 | 48 | /* Frees any memory used for the buffer. */ |
49 | ||
50 | void | |
51 | buffer_free(Buffer *buffer) | |
52 | { | |
b51b59a5 | 53 | if (buffer->alloc > 0) { |
54 | memset(buffer->buf, 0, buffer->alloc); | |
acc3d05e | 55 | buffer->alloc = 0; |
b51b59a5 | 56 | xfree(buffer->buf); |
57 | } | |
3c0ef626 | 58 | } |
59 | ||
60 | /* | |
61 | * Clears any data from the buffer, making it empty. This does not actually | |
62 | * zero the memory. | |
63 | */ | |
64 | ||
65 | void | |
66 | buffer_clear(Buffer *buffer) | |
67 | { | |
68 | buffer->offset = 0; | |
69 | buffer->end = 0; | |
70 | } | |
71 | ||
72 | /* Appends data to the buffer, expanding it if necessary. */ | |
73 | ||
74 | void | |
e9a17296 | 75 | buffer_append(Buffer *buffer, const void *data, u_int len) |
3c0ef626 | 76 | { |
e9a17296 | 77 | void *p; |
78 | p = buffer_append_space(buffer, len); | |
79 | memcpy(p, data, len); | |
3c0ef626 | 80 | } |
81 | ||
9108f8d9 | 82 | static int |
83 | buffer_compact(Buffer *buffer) | |
84 | { | |
85 | /* | |
86 | * If the buffer is quite empty, but all data is at the end, move the | |
87 | * data to the beginning. | |
88 | */ | |
89 | if (buffer->offset > MIN(buffer->alloc, BUFFER_MAX_CHUNK)) { | |
90 | memmove(buffer->buf, buffer->buf + buffer->offset, | |
91 | buffer->end - buffer->offset); | |
92 | buffer->end -= buffer->offset; | |
93 | buffer->offset = 0; | |
94 | return (1); | |
95 | } | |
96 | return (0); | |
97 | } | |
98 | ||
3c0ef626 | 99 | /* |
100 | * Appends space to the buffer, expanding the buffer if necessary. This does | |
101 | * not actually copy the data into the buffer, but instead returns a pointer | |
102 | * to the allocated region. | |
103 | */ | |
104 | ||
e9a17296 | 105 | void * |
106 | buffer_append_space(Buffer *buffer, u_int len) | |
3c0ef626 | 107 | { |
0fff78ff | 108 | u_int newlen; |
bed7ee6f | 109 | u_int buf_max; |
110 | u_int buf_alloc_sz; | |
e9a17296 | 111 | void *p; |
112 | ||
dec6d9fe | 113 | if (len > BUFFER_MAX_CHUNK) |
680cee3b | 114 | fatal("buffer_append_space: len %u not supported", len); |
115 | ||
3c0ef626 | 116 | /* If the buffer is empty, start using it from the beginning. */ |
117 | if (buffer->offset == buffer->end) { | |
118 | buffer->offset = 0; | |
119 | buffer->end = 0; | |
120 | } | |
121 | restart: | |
122 | /* If there is enough space to store all data, store it now. */ | |
123 | if (buffer->end + len < buffer->alloc) { | |
e9a17296 | 124 | p = buffer->buf + buffer->end; |
3c0ef626 | 125 | buffer->end += len; |
e9a17296 | 126 | return p; |
3c0ef626 | 127 | } |
9108f8d9 | 128 | |
129 | /* Compact data back to the start of the buffer if necessary */ | |
130 | if (buffer_compact(buffer)) | |
3c0ef626 | 131 | goto restart; |
cdd66111 | 132 | |
bed7ee6f | 133 | // if hpn is disabled use the smaller buffer size |
134 | buf_max = BUFFER_MAX_LEN_HPN; | |
135 | buf_alloc_sz = BUFFER_ALLOCSZ_HPN; | |
136 | ||
9108f8d9 | 137 | /* Increase the size of the buffer and retry. */ |
bed7ee6f | 138 | newlen = roundup(buffer->alloc + len, buf_alloc_sz); |
139 | ||
140 | ||
141 | if (newlen > buf_max) | |
680cee3b | 142 | fatal("buffer_append_space: alloc %u not supported", |
0fff78ff | 143 | newlen); |
9108f8d9 | 144 | buffer->buf = xrealloc(buffer->buf, 1, newlen); |
0fff78ff | 145 | buffer->alloc = newlen; |
3c0ef626 | 146 | goto restart; |
e9a17296 | 147 | /* NOTREACHED */ |
3c0ef626 | 148 | } |
149 | ||
9108f8d9 | 150 | /* |
151 | * Check whether an allocation of 'len' will fit in the buffer | |
152 | * This must follow the same math as buffer_append_space | |
153 | */ | |
154 | int | |
155 | buffer_check_alloc(Buffer *buffer, u_int len) | |
156 | { | |
bed7ee6f | 157 | u_int buf_max; |
158 | u_int buf_alloc_sz; | |
159 | ||
9108f8d9 | 160 | if (buffer->offset == buffer->end) { |
161 | buffer->offset = 0; | |
162 | buffer->end = 0; | |
163 | } | |
164 | restart: | |
165 | if (buffer->end + len < buffer->alloc) | |
166 | return (1); | |
167 | if (buffer_compact(buffer)) | |
168 | goto restart; | |
bed7ee6f | 169 | |
170 | // if hpn is disabled use the smaller buffer size | |
171 | buf_max = BUFFER_MAX_LEN_HPN; | |
172 | buf_alloc_sz = BUFFER_ALLOCSZ_HPN; | |
173 | ||
174 | if (roundup(buffer->alloc + len, buf_alloc_sz) <= buf_max) | |
9108f8d9 | 175 | return (1); |
176 | return (0); | |
177 | } | |
178 | ||
3c0ef626 | 179 | /* Returns the number of bytes of data in the buffer. */ |
180 | ||
181 | u_int | |
182 | buffer_len(Buffer *buffer) | |
183 | { | |
184 | return buffer->end - buffer->offset; | |
185 | } | |
186 | ||
187 | /* Gets data from the beginning of the buffer. */ | |
188 | ||
996d5e62 | 189 | int |
190 | buffer_get_ret(Buffer *buffer, void *buf, u_int len) | |
3c0ef626 | 191 | { |
996d5e62 | 192 | if (len > buffer->end - buffer->offset) { |
193 | error("buffer_get_ret: trying to get more bytes %d than in buffer %d", | |
3c0ef626 | 194 | len, buffer->end - buffer->offset); |
996d5e62 | 195 | return (-1); |
196 | } | |
3c0ef626 | 197 | memcpy(buf, buffer->buf + buffer->offset, len); |
198 | buffer->offset += len; | |
996d5e62 | 199 | return (0); |
200 | } | |
201 | ||
202 | void | |
203 | buffer_get(Buffer *buffer, void *buf, u_int len) | |
204 | { | |
205 | if (buffer_get_ret(buffer, buf, len) == -1) | |
206 | fatal("buffer_get: buffer error"); | |
3c0ef626 | 207 | } |
208 | ||
209 | /* Consumes the given number of bytes from the beginning of the buffer. */ | |
210 | ||
996d5e62 | 211 | int |
212 | buffer_consume_ret(Buffer *buffer, u_int bytes) | |
213 | { | |
214 | if (bytes > buffer->end - buffer->offset) { | |
215 | error("buffer_consume_ret: trying to get more bytes than in buffer"); | |
216 | return (-1); | |
217 | } | |
218 | buffer->offset += bytes; | |
219 | return (0); | |
220 | } | |
221 | ||
3c0ef626 | 222 | void |
223 | buffer_consume(Buffer *buffer, u_int bytes) | |
224 | { | |
996d5e62 | 225 | if (buffer_consume_ret(buffer, bytes) == -1) |
226 | fatal("buffer_consume: buffer error"); | |
3c0ef626 | 227 | } |
228 | ||
229 | /* Consumes the given number of bytes from the end of the buffer. */ | |
230 | ||
996d5e62 | 231 | int |
232 | buffer_consume_end_ret(Buffer *buffer, u_int bytes) | |
233 | { | |
234 | if (bytes > buffer->end - buffer->offset) | |
235 | return (-1); | |
236 | buffer->end -= bytes; | |
237 | return (0); | |
238 | } | |
239 | ||
3c0ef626 | 240 | void |
241 | buffer_consume_end(Buffer *buffer, u_int bytes) | |
242 | { | |
996d5e62 | 243 | if (buffer_consume_end_ret(buffer, bytes) == -1) |
3c0ef626 | 244 | fatal("buffer_consume_end: trying to get more bytes than in buffer"); |
3c0ef626 | 245 | } |
246 | ||
247 | /* Returns a pointer to the first used byte in the buffer. */ | |
248 | ||
e9a17296 | 249 | void * |
3c0ef626 | 250 | buffer_ptr(Buffer *buffer) |
251 | { | |
252 | return buffer->buf + buffer->offset; | |
253 | } | |
254 | ||
255 | /* Dumps the contents of the buffer to stderr. */ | |
256 | ||
257 | void | |
258 | buffer_dump(Buffer *buffer) | |
259 | { | |
cdd66111 | 260 | u_int i; |
e9a17296 | 261 | u_char *ucp = buffer->buf; |
3c0ef626 | 262 | |
263 | for (i = buffer->offset; i < buffer->end; i++) { | |
264 | fprintf(stderr, "%02x", ucp[i]); | |
265 | if ((i-buffer->offset)%16==15) | |
266 | fprintf(stderr, "\r\n"); | |
267 | else if ((i-buffer->offset)%2==1) | |
268 | fprintf(stderr, " "); | |
269 | } | |
270 | fprintf(stderr, "\r\n"); | |
271 | } |