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Buffer: add ssh_buffer_(un)pack()

That function permits chaining of buffer values to minimize buffer handling
in packet sending code.

Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
Этот коммит содержится в:
Aris Adamantiadis 2014-04-09 20:55:38 +02:00 коммит произвёл Andreas Schneider
родитель 13c42bff3f
Коммит 835e34d1eb
2 изменённых файлов: 301 добавлений и 0 удалений

Просмотреть файл

@ -21,6 +21,8 @@
#ifndef BUFFER_H_ #ifndef BUFFER_H_
#define BUFFER_H_ #define BUFFER_H_
#include <stdarg.h>
#include "libssh/libssh.h" #include "libssh/libssh.h"
/* /*
* Describes a buffer state * Describes a buffer state
@ -46,6 +48,10 @@ int buffer_add_u16(ssh_buffer buffer, uint16_t data);
int buffer_add_u32(ssh_buffer buffer, uint32_t data); int buffer_add_u32(ssh_buffer buffer, uint32_t data);
int buffer_add_u64(ssh_buffer buffer, uint64_t data); int buffer_add_u64(ssh_buffer buffer, uint64_t data);
int ssh_buffer_add_data(ssh_buffer buffer, const void *data, uint32_t len); int ssh_buffer_add_data(ssh_buffer buffer, const void *data, uint32_t len);
int ssh_buffer_pack_va(struct ssh_buffer_struct *buffer, const char *format, va_list ap);
int ssh_buffer_pack(struct ssh_buffer_struct *buffer, const char *format, ...);
int ssh_buffer_unpack_va(struct ssh_buffer_struct *buffer, const char *format, va_list ap);
int ssh_buffer_unpack(struct ssh_buffer_struct *buffer, const char *format, ...);
int buffer_prepend_data(ssh_buffer buffer, const void *data, uint32_t len); int buffer_prepend_data(ssh_buffer buffer, const void *data, uint32_t len);
int buffer_add_buffer(ssh_buffer buffer, ssh_buffer source); int buffer_add_buffer(ssh_buffer buffer, ssh_buffer source);
int ssh_buffer_reinit(ssh_buffer buffer); int ssh_buffer_reinit(ssh_buffer buffer);

Просмотреть файл

@ -24,6 +24,7 @@
#include <limits.h> #include <limits.h>
#include <stdlib.h> #include <stdlib.h>
#include <string.h> #include <string.h>
#include <stdarg.h>
#ifndef _WIN32 #ifndef _WIN32
#include <netinet/in.h> #include <netinet/in.h>
@ -32,6 +33,8 @@
#include "libssh/priv.h" #include "libssh/priv.h"
#include "libssh/buffer.h" #include "libssh/buffer.h"
#include "libssh/misc.h"
#include "libssh/dh.h"
/** /**
* @defgroup libssh_buffer The SSH buffer functions. * @defgroup libssh_buffer The SSH buffer functions.
@ -645,6 +648,298 @@ struct ssh_string_struct *buffer_get_mpint(struct ssh_buffer_struct *buffer) {
return str; return str;
} }
/** @internal
* @brief Add multiple values in a buffer on a single function call
* @param[in] buffer The buffer to add to
* @param[in] format A format string of arguments.
* @param[in] ap A va_list of arguments.
* @returns SSH_OK on success
* SSH_ERROR on error
* @see ssh_buffer_add_format() for format list values.
*/
int ssh_buffer_pack_va(struct ssh_buffer_struct *buffer, const char *format, va_list ap){
int rc;
const char *p;
union {
uint8_t byte;
uint16_t word;
uint32_t dword;
uint64_t qword;
ssh_string string;
void *data;
} o;
char *cstring;
bignum b;
size_t len;
for (p = format; *p != '\0'; p++) {
switch(*p) {
case 'b':
o.byte = (uint8_t)va_arg(ap, unsigned int);
rc = buffer_add_u8(buffer, o.byte);
break;
case 'w':
o.word = (uint16_t)va_arg(ap, unsigned int);
o.word = htons(o.word);
rc = buffer_add_u16(buffer, o.word);
break;
case 'd':
o.dword = va_arg(ap, uint32_t);
o.dword = htonl(o.dword);
rc = buffer_add_u32(buffer, o.dword);
break;
case 'q':
o.qword = va_arg(ap, uint64_t);
o.qword = htonll(o.qword);
rc = buffer_add_u64(buffer, o.qword);
break;
case 'S':
o.string = va_arg(ap, ssh_string);
rc = buffer_add_ssh_string(buffer, o.string);
o.string = NULL;
break;
case 's':
cstring = va_arg(ap, char *);
len = strlen(cstring);
rc = buffer_add_u32(buffer, htonl(len));
if (rc == SSH_OK){
rc = ssh_buffer_add_data(buffer, cstring, len);
}
cstring = NULL;
break;
case 'P':
len = va_arg(ap, size_t);
o.data = va_arg(ap, void *);
rc = ssh_buffer_add_data(buffer, o.data, len);
o.data = NULL;
break;
case 'B':
b = va_arg(ap, bignum);
o.string = make_bignum_string(b);
if(o.string == NULL){
rc = SSH_ERROR;
break;
}
rc = buffer_add_ssh_string(buffer, o.string);
SAFE_FREE(o.string);
break;
default:
SSH_LOG(SSH_LOG_WARN, "Invalid buffer format %c", *p);
rc = SSH_ERROR;
}
if (rc != SSH_OK){
break;
}
}
return rc;
}
/** @internal
* @brief Add multiple values in a buffer on a single function call
* @param[in] buffer The buffer to add to
* @param[in] format A format string of arguments. This string contains single
* letters describing the order and type of arguments:
* 'b': uint8_t (pushed in network byte order)
* 'w': uint16_t (pushed in network byte order)
* 'd': uint32_t (pushed in network byte order)
* 'q': uint64_t (pushed in network byte order)
* 'S': ssh_string
* 's': char * (C string, pushed as SSH string)
* 'P': size_t, void * (len of data, pointer to data)
* only pushes data.
* 'S': bignum (pushed as SSH string)
* @returns SSH_OK on success
* SSH_ERROR on error
* @warning when using 'P' with a constant size (e.g. 8), do not
* forget to cast to (size_t).
*/
int ssh_buffer_pack(struct ssh_buffer_struct *buffer, const char *format, ...){
va_list ap;
int rc;
va_start(ap, format);
rc = ssh_buffer_pack_va(buffer, format, ap);
va_end(ap);
return rc;
}
/** @internal
* @brief Get multiple values from a buffer on a single function call
* @param[in] buffer The buffer to get from
* @param[in] format A format string of arguments.
* @param[in] ap A va_list of arguments.
* @returns SSH_OK on success
* SSH_ERROR on error
* @see ssh_buffer_get_format() for format list values.
*/
int ssh_buffer_unpack_va(struct ssh_buffer_struct *buffer, const char *format, va_list ap){
int rc;
const char *p, *last;
union {
uint8_t *byte;
uint16_t *word;
uint32_t *dword;
uint64_t *qword;
ssh_string *string;
char **cstring;
void **data;
} o;
size_t len, rlen;
uint32_t u32len;
va_list ap_copy;
/* copy the argument list in case a rollback is needed */
va_copy(ap_copy, ap);
for (p = format; *p != '\0'; p++) {
switch (*p) {
case 'b':
o.byte = va_arg(ap, uint8_t *);
rlen = buffer_get_u8(buffer, o.byte);
rc = rlen==1 ? SSH_OK : SSH_ERROR;
break;
case 'w':
o.word = va_arg(ap, uint16_t *);
rlen = buffer_get_data(buffer, o.word, sizeof(uint16_t));
*o.word = ntohs(*o.word);
rc = rlen==2 ? SSH_OK : SSH_ERROR;
break;
case 'd':
o.dword = va_arg(ap, uint32_t *);
rlen = buffer_get_u32(buffer, o.dword);
*o.dword = ntohl(*o.dword);
rc = rlen==4 ? SSH_OK : SSH_ERROR;
break;
case 'q':
o.qword = va_arg(ap, uint64_t*);
rlen = buffer_get_u64(buffer, o.qword);
*o.qword = ntohll(*o.qword);
rc = rlen==8 ? SSH_OK : SSH_ERROR;
break;
case 'S':
o.string = va_arg(ap, ssh_string *);
*o.string = buffer_get_ssh_string(buffer);
rc = *o.string != NULL ? SSH_OK : SSH_ERROR;
o.string = NULL;
break;
case 's':
o.cstring = va_arg(ap, char **);
*o.cstring = NULL;
rc = buffer_get_u32(buffer, &u32len);
if (rc != 4){
rc = SSH_ERROR;
break;
}
len = ntohl(u32len);
if (len > UINT_MAX - 1){
rc = SSH_ERROR;
break;
}
*o.cstring = malloc(len + 1);
if (*o.cstring == NULL){
rc = SSH_ERROR;
break;
}
rlen = buffer_get_data(buffer, *o.cstring, len);
if (rlen != len){
SAFE_FREE(*o.cstring);
rc = SSH_ERROR;
break;
}
(*o.cstring)[len] = '\0';
o.cstring = NULL;
rc = SSH_OK;
break;
case 'P':
len = va_arg(ap, size_t);
o.data = va_arg(ap, void **);
*o.data = malloc(len);
if(*o.data == NULL){
rc = SSH_ERROR;
break;
}
rlen = buffer_get_data(buffer, *o.data, len);
if (rlen != len){
SAFE_FREE(*o.data);
rc = SSH_ERROR;
break;
}
o.data = NULL;
rc = SSH_OK;
break;
default:
SSH_LOG(SSH_LOG_WARN, "Invalid buffer format %c", *p);
rc = SSH_ERROR;
}
if (rc != SSH_OK) {
break;
}
}
if (rc != SSH_OK){
/* Reset the format string and erase everything that was allocated */
last = p;
for(p=format;p<last;++p){
switch(*p){
case 'b':
case 'w':
case 'd':
case 'q':
va_arg(ap_copy, void *);
break;
case 'S':
o.string=va_arg(ap_copy, ssh_string *);
SAFE_FREE(*o.string);
break;
case 's':
o.cstring=va_arg(ap_copy, char **);
SAFE_FREE(*o.cstring);
break;
case 'P':
va_arg(ap_copy, size_t);
o.data = va_arg(ap_copy, void **);
SAFE_FREE(*o.data);
break;
default:
va_arg(ap_copy, void *);
break;
}
}
}
va_end(ap_copy);
return rc;
}
/** @internal
* @brief Get multiple values from a buffer on a single function call
* @param[in] buffer The buffer to get from
* @param[in] format A format string of arguments. This string contains single
* letters describing the order and type of arguments:
* 'b': uint8_t * (pulled in network byte order)
* 'w': uint16_t * (pulled in network byte order)
* 'd': uint32_t * (pulled in network byte order)
* 'q': uint64_t * (pulled in network byte order)
* 'S': ssh_string *
* 's': char ** (C string, pulled as SSH string)
* 'P': size_t, void ** (len of data, pointer to data)
* only pulls data.
* @returns SSH_OK on success
* SSH_ERROR on error
* @warning when using 'P' with a constant size (e.g. 8), do not
* forget to cast to (size_t).
*/
int ssh_buffer_unpack(struct ssh_buffer_struct *buffer, const char *format, ...){
va_list ap;
int rc;
va_start(ap, format);
rc = ssh_buffer_unpack_va(buffer, format, ap);
va_end(ap);
return rc;
}
/** @} */ /** @} */
/* vim: set ts=4 sw=4 et cindent: */ /* vim: set ts=4 sw=4 et cindent: */