diff options
Diffstat (limited to 'source/include/byteorder.h')
| -rw-r--r-- | source/include/byteorder.h | 165 |
1 files changed, 164 insertions, 1 deletions
diff --git a/source/include/byteorder.h b/source/include/byteorder.h index 899cd6c4991..3371fd24cbc 100644 --- a/source/include/byteorder.h +++ b/source/include/byteorder.h @@ -2,7 +2,7 @@ Unix SMB/Netbios implementation. Version 1.9. SMB Byte handling - Copyright (C) Andrew Tridgell 1992-1995 + Copyright (C) Andrew Tridgell 1992-1998 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 @@ -22,8 +22,98 @@ /* This file implements macros for machine independent short and int manipulation + +Here is a description of this file that I emailed to the samba list once: + +> I am confused about the way that byteorder.h works in Samba. I have +> looked at it, and I would have thought that you might make a distinction +> between LE and BE machines, but you only seem to distinguish between 386 +> and all other architectures. +> +> Can you give me a clue? + +sure. + +The distinction between 386 and other architectures is only there as +an optimisation. You can take it out completely and it will make no +difference. The routines (macros) in byteorder.h are totally byteorder +independent. The 386 optimsation just takes advantage of the fact that +the x86 processors don't care about alignment, so we don't have to +align ints on int boundaries etc. If there are other processors out +there that aren't alignment sensitive then you could also define +CAREFUL_ALIGNMENT=0 on those processors as well. + +Ok, now to the macros themselves. I'll take a simple example, say we +want to extract a 2 byte integer from a SMB packet and put it into a +type called uint16 that is in the local machines byte order, and you +want to do it with only the assumption that uint16 is _at_least_ 16 +bits long (this last condition is very important for architectures +that don't have any int types that are 2 bytes long) + +You do this: + +#define CVAL(buf,pos) (((unsigned char *)(buf))[pos]) +#define PVAL(buf,pos) ((unsigned)CVAL(buf,pos)) +#define SVAL(buf,pos) (PVAL(buf,pos)|PVAL(buf,(pos)+1)<<8) + +then to extract a uint16 value at offset 25 in a buffer you do this: + +char *buffer = foo_bar(); +uint16 xx = SVAL(buffer,25); + +We are using the byteoder independence of the ANSI C bitshifts to do +the work. A good optimising compiler should turn this into efficient +code, especially if it happens to have the right byteorder :-) + +I know these macros can be made a bit tidier by removing some of the +casts, but you need to look at byteorder.h as a whole to see the +reasoning behind them. byteorder.h defines the following macros: + +SVAL(buf,pos) - extract a 2 byte SMB value +IVAL(buf,pos) - extract a 4 byte SMB value +SVALS(buf,pos) signed version of SVAL() +IVALS(buf,pos) signed version of IVAL() + +SSVAL(buf,pos,val) - put a 2 byte SMB value into a buffer +SIVAL(buf,pos,val) - put a 4 byte SMB value into a buffer +SSVALS(buf,pos,val) - signed version of SSVAL() +SIVALS(buf,pos,val) - signed version of SIVAL() + +RSVAL(buf,pos) - like SVAL() but for NMB byte ordering +RIVAL(buf,pos) - like IVAL() but for NMB byte ordering +RSSVAL(buf,pos,val) - like SSVAL() but for NMB ordering +RSIVAL(buf,pos,val) - like SIVAL() but for NMB ordering + +it also defines lots of intermediate macros, just ignore those :-) + */ +/* some switch macros that do both store and read to and from SMB buffers */ + +#define RW_PCVAL(read,inbuf,outbuf,len) \ + if (read) { PCVAL (inbuf,0,outbuf,len) } \ + else { PSCVAL(inbuf,0,outbuf,len) } + +#define RW_PIVAL(read,inbuf,outbuf,len) \ + if (read) { PIVAL (inbuf,0,outbuf,len) } \ + else { PSIVAL(inbuf,0,outbuf,len) } + +#define RW_PSVAL(read,inbuf,outbuf,len) \ + if (read) { PSVAL (inbuf,0,outbuf,len) } \ + else { PSSVAL(inbuf,0,outbuf,len) } + +#define RW_CVAL(read, inbuf, outbuf, offset) \ + if (read) (outbuf) = CVAL (inbuf,offset); \ + else SCVAL(inbuf,offset,outbuf); + +#define RW_IVAL(read, inbuf, outbuf, offset) \ + if (read) (outbuf)= IVAL (inbuf,offset); \ + else SIVAL(inbuf,offset,outbuf); + +#define RW_SVAL(read, inbuf, outbuf, offset) \ + if (read) (outbuf)= SVAL (inbuf,offset); \ + else SSVAL(inbuf,offset,outbuf); + #undef CAREFUL_ALIGNMENT /* we know that the 386 can handle misalignment and has the "right" @@ -42,6 +132,7 @@ #if CAREFUL_ALIGNMENT + #define SVAL(buf,pos) (PVAL(buf,pos)|PVAL(buf,(pos)+1)<<8) #define IVAL(buf,pos) (SVAL(buf,pos)|SVAL(buf,(pos)+2)<<16) #define SSVALX(buf,pos,val) (CVAL(buf,pos)=(val)&0xFF,CVAL(buf,pos+1)=(val)>>8) @@ -52,24 +143,56 @@ #define SIVAL(buf,pos,val) SIVALX((buf),(pos),((uint32)(val))) #define SSVALS(buf,pos,val) SSVALX((buf),(pos),((int16)(val))) #define SIVALS(buf,pos,val) SIVALX((buf),(pos),((int32)(val))) + #else + /* this handles things for architectures like the 386 that can handle alignment errors */ /* WARNING: This section is dependent on the length of int16 and int32 being correct */ + +/* get single value from an SMB buffer */ #define SVAL(buf,pos) (*(uint16 *)((char *)(buf) + (pos))) #define IVAL(buf,pos) (*(uint32 *)((char *)(buf) + (pos))) #define SVALS(buf,pos) (*(int16 *)((char *)(buf) + (pos))) #define IVALS(buf,pos) (*(int32 *)((char *)(buf) + (pos))) + +/* store single value in an SMB buffer */ #define SSVAL(buf,pos,val) SVAL(buf,pos)=((uint16)(val)) #define SIVAL(buf,pos,val) IVAL(buf,pos)=((uint32)(val)) #define SSVALS(buf,pos,val) SVALS(buf,pos)=((int16)(val)) #define SIVALS(buf,pos,val) IVALS(buf,pos)=((int32)(val)) + #endif +/* macros for reading / writing arrays */ + +#define SMBMACRO(macro,buf,pos,val,len,size) \ +{ int l; for (l = 0; l < (len); l++) (val)[l] = macro((buf), (pos) + (size)*l); } + +#define SSMBMACRO(macro,buf,pos,val,len,size) \ +{ int l; for (l = 0; l < (len); l++) macro((buf), (pos) + (size)*l, (val)[l]); } + +/* reads multiple data from an SMB buffer */ +#define PCVAL(buf,pos,val,len) SMBMACRO(CVAL,buf,pos,val,len,1) +#define PSVAL(buf,pos,val,len) SMBMACRO(SVAL,buf,pos,val,len,2) +#define PIVAL(buf,pos,val,len) SMBMACRO(IVAL,buf,pos,val,len,4) +#define PCVALS(buf,pos,val,len) SMBMACRO(CVALS,buf,pos,val,len,1) +#define PSVALS(buf,pos,val,len) SMBMACRO(SVALS,buf,pos,val,len,2) +#define PIVALS(buf,pos,val,len) SMBMACRO(IVALS,buf,pos,val,len,4) + +/* stores multiple data in an SMB buffer */ +#define PSCVAL(buf,pos,val,len) SSMBMACRO(SCVAL,buf,pos,val,len,1) +#define PSSVAL(buf,pos,val,len) SSMBMACRO(SSVAL,buf,pos,val,len,2) +#define PSIVAL(buf,pos,val,len) SSMBMACRO(SIVAL,buf,pos,val,len,4) +#define PSCVALS(buf,pos,val,len) SSMBMACRO(SCVALS,buf,pos,val,len,1) +#define PSSVALS(buf,pos,val,len) SSMBMACRO(SSVALS,buf,pos,val,len,2) +#define PSIVALS(buf,pos,val,len) SSMBMACRO(SIVALS,buf,pos,val,len,4) + + /* now the reverse routines - these are used in nmb packets (mostly) */ #define SREV(x) ((((x)&0xFF)<<8) | (((x)>>8)&0xFF)) #define IREV(x) ((SREV(x)<<16) | (SREV((x)>>16))) @@ -78,3 +201,43 @@ #define RIVAL(buf,pos) IREV(IVAL(buf,pos)) #define RSSVAL(buf,pos,val) SSVAL(buf,pos,SREV(val)) #define RSIVAL(buf,pos,val) SIVAL(buf,pos,IREV(val)) + +#define DBG_RW_PCVAL(charmode,string,depth,base,read,inbuf,outbuf,len) \ + RW_PCVAL(read,inbuf,outbuf,len) \ + DEBUG(5,("%s%04x %s: ", \ + tab_depth(depth), PTR_DIFF(inbuf,base),string)); \ + if (charmode) print_asc(5, (unsigned char*)(outbuf), (len)); else \ + { int idx; for (idx = 0; idx < len; idx++) { DEBUG(5,("%02x ", (outbuf)[idx])); } } \ + DEBUG(5,("\n")); + +#define DBG_RW_PSVAL(charmode,string,depth,base,read,inbuf,outbuf,len) \ + RW_PSVAL(read,inbuf,outbuf,len) \ + DEBUG(5,("%s%04x %s: ", \ + tab_depth(depth), PTR_DIFF(inbuf,base),string)); \ + if (charmode) print_asc(5, (unsigned char*)(outbuf), 2*(len)); else \ + { int idx; for (idx = 0; idx < len; idx++) { DEBUG(5,("%04x ", (outbuf)[idx])); } } \ + DEBUG(5,("\n")); + +#define DBG_RW_PIVAL(charmode,string,depth,base,read,inbuf,outbuf,len) \ + RW_PIVAL(read,inbuf,outbuf,len) \ + DEBUG(5,("%s%04x %s: ", \ + tab_depth(depth), PTR_DIFF(inbuf,base),string)); \ + if (charmode) print_asc(5, (unsigned char*)(outbuf), 4*(len)); else \ + { int idx; for (idx = 0; idx < len; idx++) { DEBUG(5,("%08x ", (outbuf)[idx])); } } \ + DEBUG(5,("\n")); + +#define DBG_RW_CVAL(string,depth,base,read,inbuf,outbuf) \ + RW_CVAL(read,inbuf,outbuf,0) \ + DEBUG(5,("%s%04x %s: %02x\n", \ + tab_depth(depth), PTR_DIFF(inbuf,base), string, outbuf)); + +#define DBG_RW_SVAL(string,depth,base,read,inbuf,outbuf) \ + RW_SVAL(read,inbuf,outbuf,0) \ + DEBUG(5,("%s%04x %s: %04x\n", \ + tab_depth(depth), PTR_DIFF(inbuf,base), string, outbuf)); + +#define DBG_RW_IVAL(string,depth,base,read,inbuf,outbuf) \ + RW_IVAL(read,inbuf,outbuf,0) \ + DEBUG(5,("%s%04x %s: %08x\n", \ + tab_depth(depth), PTR_DIFF(inbuf,base), string, outbuf)); + |