serval-dna/overlay_buffer.c

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2011-12-21 09:55:05 +00:00
/*
Serval Distributed Numbering Architecture (DNA)
Copyright (C) 2010 Paul Gardner-Stephen
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/
#include "serval.h"
overlay_buffer *ob_new(int size)
{
overlay_buffer *ret=calloc(sizeof(overlay_buffer),1);
if (!ret) return NULL;
ob_unlimitsize(ret);
return ret;
}
// index an existing static buffer.
// and allow other callers to use the ob_ convenience methods for reading and writing up to size bytes.
overlay_buffer *ob_static(unsigned char *bytes, int size){
overlay_buffer *ret=calloc(sizeof(overlay_buffer),1);
if (!ret) return NULL;
ret->bytes = bytes;
ret->allocSize =-1;
ret->sizeLimit=size;
return ret;
}
int ob_free(overlay_buffer *b)
{
if (!b) return WHY("Asked to free NULL");
if (b->bytes && b->allocSize>0) free(b->bytes);
b->bytes=NULL;
b->allocSize=0;
b->sizeLimit=0;
free(b);
return 0;
}
int ob_checkpoint(overlay_buffer *b)
{
if (!b) return WHY("Asked to checkpoint NULL");
b->checkpointLength=b->length;
return 0;
}
int ob_rewind(overlay_buffer *b)
{
if (!b) return WHY("Asked to rewind NULL");
b->length=b->checkpointLength;
return 0;
}
int ob_setlength(overlay_buffer *b,int bytes){
if (bytes > b->sizeLimit) return WHY("Length exceeds size limit");
if (b->allocSize>=0 && bytes > b->allocSize) return WHY("Length exceeds allocated size");
b->length=bytes;
return 0;
}
int ob_limitsize(overlay_buffer *b,int bytes)
{
if (!b) return WHY("Asked to limit size of NULL");
if (b->length>bytes) return WHY("Length of data in buffer already exceeds size limit");
if (b->checkpointLength>bytes) return WHY("Checkpointed length of data in buffer already exceeds size limit");
if (bytes<0) return WHY("Can't limit buffer to a negative size");
if (b->allocSize<0) return WHY("Can't change the limit of a static buffer");
b->sizeLimit=bytes;
return 0;
}
int ob_unlimitsize(overlay_buffer *b)
{
if (!b) return WHY("b is NULL");
if (b->allocSize<0) return WHY("Can't change the limit of a static buffer");
b->sizeLimit=-1;
return 0;
}
int ob_makespace(overlay_buffer *b,int bytes)
{
if (b->sizeLimit!=-1 && b->length+bytes>b->sizeLimit) {
if (debug&DEBUG_PACKETFORMATS) WHY("Asked to make space beyond size limit");
return -1;
}
if (b->allocSize<0){
return WHY("Can't resize a static buffer");
}
if (0)
DEBUGF("ob_makespace(%p,%d)\n b->bytes=%p,b->length=%d,b->allocSize=%d\n",
b,bytes,b->bytes,b->length,b->allocSize);
if (b->length+bytes>=b->allocSize)
{
int newSize=b->length+bytes;
if (newSize<64) newSize=64;
if (newSize&63) newSize+=64-(newSize&63);
if (newSize>1024) {
if (newSize&1023) newSize+=1024-(newSize&1023);
}
if (newSize>65536) {
if (newSize&65535) newSize+=65536-(newSize&65535);
}
if (0) DEBUGF("realloc(b->bytes=%p,newSize=%d)", b->bytes,newSize);
/* XXX OSX realloc() seems to be able to corrupt things if the heap is not happy when calling realloc(), making debugging memory corruption much harder.
So will do a three-stage malloc,bcopy,free to see if we can tease the bug out that way. */
/*
unsigned char *r=realloc(b->bytes,newSize);
if (!r) return WHY("realloc() failed");
b->bytes=r;
*/
#ifdef MALLOC_PARANOIA
#warning adding lots of padding to try to catch overruns
if (b->bytes) {
int i;
int corrupt=0;
for(i=0;i<4096;i++) if (b->bytes[b->allocSize+i]!=0xbd) corrupt++;
if (corrupt) {
WHYF("!!!!!! %d corrupted bytes in overrun catch tray", corrupt);
dump("overrun catch tray",&b->bytes[b->allocSize],4096);
sleep(3600);
}
}
unsigned char *new=malloc(newSize+4096);
if (!new) return WHY("realloc() failed");
{
int i;
for(i=0;i<4096;i++) new[newSize+i]=0xbd;
}
#else
unsigned char *new=malloc(newSize);
#endif
bcopy(b->bytes,new,b->length);
if (b->bytes) free(b->bytes);
b->bytes=new;
b->allocSize=newSize;
return 0;
}
else
return 0;
}
/*
Functions that append data and increase the size of the buffer if possible / required
*/
int ob_append_byte(overlay_buffer *b,unsigned char byte)
{
if (ob_makespace(b,1)) return WHY("ob_makespace() failed");
b->bytes[b->length++] = byte;
return 0;
}
unsigned char *ob_append_space(overlay_buffer *b,int count)
{
if (ob_makespace(b,count)) { WHY("ob_makespace() failed"); return NULL; }
unsigned char *r=&b->bytes[b->length];
b->length+=count;
return r;
}
int ob_append_bytes(overlay_buffer *b,unsigned char *bytes,int count)
{
if (ob_makespace(b,count)) return WHY("ob_makespace() failed");
bcopy(bytes,&b->bytes[b->length],count);
b->length+=count;
return 0;
}
int ob_append_short(overlay_buffer *b,unsigned short v)
{
unsigned short s=htons(v);
return ob_append_bytes(b,(unsigned char *)&s,sizeof(unsigned short));
}
int ob_append_int(overlay_buffer *b,unsigned int v)
{
unsigned int s=htonl(v);
return ob_append_bytes(b,(unsigned char *)&s,sizeof(unsigned int));
}
int ob_append_rfs(overlay_buffer *b,int l)
{
/* Encode the specified length and append it to the buffer */
if (l<0||l>0xffff) return -1;
/* First work out how long the field needs to be, then write dummy bytes
and use ob_patch_rfs to set the value. That way we have only one
lot of code that does the encoding. */
b->var_length_offset=b->length;
b->var_length_bytes=rfs_length(l);
unsigned char c[3]={0,0,0};
if (ob_append_bytes(b,c,b->var_length_bytes)) {
b->var_length_offset=0;
return -1;
}
return ob_patch_rfs(b,l);
}
/*
Functions that read / write data within the existing length limit
*/
int test_offset(overlay_buffer *b,int start,int length){
if (!b) FATAL("b is NULL");
if (start<0) FATALF("passed illegal offset %d",start);
if (b->sizeLimit>=0 && start+length>b->sizeLimit) FATALF("passed offset too large %d", start+length);
if (b->allocSize>=0 && start+length>b->allocSize) FATALF("passed offset too large %d", start+length);
return 0;
}
int ob_setbyte(overlay_buffer *b,int ofs,unsigned char value)
{
test_offset(b, ofs, 1);
b->bytes[ofs]=value;
return 0;
}
int ob_getbyte(overlay_buffer *b,int ofs)
{
test_offset(b, ofs, 1);
if (ofs >= b->length) FATALF("passed offset too large %d", ofs);
return b->bytes[ofs];
}
unsigned int ob_get_int(overlay_buffer *b,int offset)
{
// TODO unsigned -1? FATAL?
test_offset(b, offset, sizeof(unsigned int));
// Some platforms require alignment
if (((uintptr_t)&b->bytes[offset])&3) {
union { unsigned char uc[4]; uint32_t ui32; } bb;
bcopy(&b->bytes[offset], &bb.uc[0], 4);
return ntohl(bb.ui32);
} else
return ntohl(*((uint32_t*)&b->bytes[offset]));
}
int rfs_length(int l)
{
if (l<0) return -1;
if (l<250) return 1;
else if (l<(255+250+(256*4))) return 2;
else if (l<=0xffff) return 3;
else return -1;
}
int rfs_encode(int l, unsigned char *b)
{
if (l<250) { b[0]=l; }
else if (l<(255+250+(256*4))) {
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l-=250;
int page=(l>>8);
l&=0xff;
b[0]=RFS_PLUS250+page;
b[1]=l;
} else {
b[0]=RFS_3BYTE;
b[1]=l>>8;
b[2]=l&0xff;
}
return 0;
}
int rfs_decode(unsigned char *b,int *ofs)
{
int rfs=b[*ofs];
switch(rfs) {
case RFS_PLUS250: case RFS_PLUS456: case RFS_PLUS762: case RFS_PLUS1018: case RFS_PLUS1274:
rfs=250+256*(rfs-RFS_PLUS250)+b[++(*ofs)];
break;
case RFS_3BYTE: rfs=(b[(*ofs)+1]<<8)+b[(*ofs)+2]; (*ofs)+=2;
default: /* Length is natural value of field, so nothing to do */
break;
}
(*ofs)++;
return rfs;
}
int ob_indel_space(overlay_buffer *b,int offset,int shift)
{
if (shift>0) { /* make space */
if (ob_makespace(b,-shift)) return -1;
bcopy(&b->bytes[offset],&b->bytes[offset+shift],b->length-(offset+shift));
} else if (shift<0) { /* free up space */
bcopy(&b->bytes[offset-shift],&b->bytes[offset],b->length-(offset-shift));
}
b->length+=shift;
return 0;
}
int ob_patch_rfs(overlay_buffer *b,int l)
{
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if (l==COMPUTE_RFS_LENGTH){
// assume the payload has been written, we can now calculate the actual length
l = b->length - (b->var_length_offset + b->var_length_bytes);
}
if (l<0||l>0xffff) return -1;
/* Adjust size of field */
int new_size=rfs_length(l);
int shift=new_size-b->var_length_bytes;
if (shift) {
if (debug&DEBUG_PACKETCONSTRUCTION) {
DEBUGF("Patching RFS for rfs_size=%d (was %d), so indel %d btyes",
new_size,b->var_length_bytes,shift);
dump("before indel",
&b->bytes[b->var_length_offset],
b->length-b->var_length_offset);
}
if (ob_indel_space(b,b->var_length_offset,shift)) return -1;
if (debug&DEBUG_PACKETCONSTRUCTION) {
dump("after indel",
&b->bytes[b->var_length_offset],
b->length-b->var_length_offset);
}
}
if (rfs_encode(l,&b->bytes[b->var_length_offset])) return -1;
if (debug&DEBUG_PACKETCONSTRUCTION) {
dump("after patch",
&b->bytes[b->var_length_offset],
b->length-b->var_length_offset);
}
return 0;
}
int asprintable(int c)
{
if (c<' ') return '.';
if (c>0x7e) return '.';
return c;
}
int ob_dump(overlay_buffer *b,char *desc)
{
DEBUGF("overlay_buffer '%s' at %p : length=%d", desc, b, b->length);
dump(NULL, b->bytes, b->length);
return 0;
}
#undef malloc
#undef calloc
#undef free
#undef realloc
#define SDM_GUARD_AFTER 16384
void *_serval_debug_malloc(unsigned int bytes,char *file,const char *func,int line)
{
void *r=malloc(bytes+SDM_GUARD_AFTER);
logMessage(LOG_LEVEL_DEBUG, file, line, func, "malloc(%d) -> %p", bytes, r);
return r;
}
void *_serval_debug_calloc(unsigned int bytes,unsigned int count,char *file,const char *func,int line)
{
void *r=calloc((bytes*count)+SDM_GUARD_AFTER,1);
logMessage(LOG_LEVEL_DEBUG, file, line, func, "calloc(%d,%d) -> %p", bytes, count, r);
return r;
}
void _serval_debug_free(void *p,char *file,const char *func,int line)
{
free(p);
logMessage(LOG_LEVEL_DEBUG, file, line, func, "free(%p)", p);
}