Correct documentation for MEID

[ric-plt/lib/rmr.git] / src / rmr / common / src / mbuf_api.c

diff --git a/src/rmr/common/src/mbuf_api.c b/src/rmr/common/src/mbuf_api.c
index 1074e37..84996ee 100644 (file)
--- a/src/rmr/common/src/mbuf_api.c
+++ b/src/rmr/common/src/mbuf_api.c
@@ -22,7 +22,9 @@
        Mnemonic:       mbuf_api.c
        Abstract:       These are common functions which work only on the mbuf and
                                thus (because they do not touch an endpoint or context)
-                               can be agnostic to the underlying transport.
+                               can be agnostic to the underlying transport, or the transport
+                               layer provides a transport specific function (e.g. payload 
+                               reallocation).
 
        Author:         E. Scott Daniels
        Date:           8 February 2019
@@ -51,6 +53,12 @@
                EINVAL id poitner, buf or buf header are bad.
                EOVERFLOW if the bytes given would have overrun
 
+       We have been told that the meid will be a string, so we enforce that even if
+       the user is copying in bytes.  We will add a 0 byte at len+1 when len is less
+       than the field size, or as the last byte (doing damage to their string) if
+       the caller didn't play by the rules. If they pass a non-nil terminated set
+       of bytes which are the field length, we'll indicate truncation.
+
 */
 extern int rmr_bytes2meid( rmr_mbuf_t* mbuf, unsigned char const* src, int len ) {
        uta_mhdr_t* hdr;
@@ -64,11 +72,20 @@ extern int rmr_bytes2meid( rmr_mbuf_t* mbuf, unsigned char const* src, int len )
        if( len > RMR_MAX_MEID ) {
                len = RMR_MAX_MEID;
                errno = EOVERFLOW;
-       }
+       } 
 
        hdr = (uta_mhdr_t *) mbuf->header;
        memcpy( hdr->meid, src, len );
 
+       if( len == RMR_MAX_MEID ) {
+               if( *(hdr->meid+len-1) != 0 ) {
+                       *(hdr->meid+len-1) = 0;
+                       errno = EOVERFLOW;
+               }
+       } else {
+               *(hdr->meid+len) = 0;
+       }
+
        return len;
 }
 
@@ -189,7 +206,40 @@ extern int rmr_str2xact( rmr_mbuf_t* mbuf, unsigned char const* str ) {
 }
 
 /*
-       Extracts the meid (managed equipment) from the header and copies the bytes
+       Extracts the transaction bytes from the header and places into a
+       user supplied buffer (dest). The buffer must be at least RMR_MAX_XID
+       bytes in length as this function will copy the entire field (even if
+       the sender saved a shorter "string." If the user supplies a nil poniter
+       as the destination, a buffer is allocated; the caller must free when
+       finished.  The buffer will be exactly RMR_MAX_XID bytes long.
+
+       The return value is a pointer to the buffer that was filled (to
+       the dest buffer provided, or the buffer we allocated). If there is an
+       error, a nil pointer is returned, and errno should suggest the root
+       cause of the issue (invalid message or no memory).
+*/
+extern unsigned char*  rmr_get_xact( rmr_mbuf_t* mbuf, unsigned char* dest ) {
+       errno = 0;
+
+       if( mbuf == NULL || mbuf->xaction == NULL ) {
+               errno = EINVAL;
+               return NULL;
+       }
+
+       if( ! dest ) {
+               if( (dest = (unsigned char *) malloc( sizeof( unsigned char ) * RMR_MAX_XID )) == NULL ) {
+                       errno = ENOMEM;
+                       return NULL;
+               }
+       }
+
+       memcpy( dest, mbuf->xaction, RMR_MAX_XID );
+
+       return dest;
+}
+
+/*
+       Extracts the meid (managed entity) from the header and copies the bytes
        to the user supplied area. If the user supplied pointer is nil, then
        a buffer will be allocated and it is the user's responsibilty to free.
        A pointer is returned to the destination memory (allocated or not)
@@ -200,6 +250,8 @@ extern int rmr_str2xact( rmr_mbuf_t* mbuf, unsigned char const* str ) {
 extern unsigned char*  rmr_get_meid( rmr_mbuf_t* mbuf, unsigned char* dest ) {
        uta_mhdr_t* hdr;
 
+       errno = 0;
+
        if( mbuf == NULL || mbuf->header == NULL ) {
                errno = EINVAL;
                return NULL;
@@ -213,7 +265,7 @@ extern unsigned char*  rmr_get_meid( rmr_mbuf_t* mbuf, unsigned char* dest ) {
        }
 
        hdr = (uta_mhdr_t *) mbuf->header;
-       memcpy( dest, hdr->meid, RMR_MAX_XID );
+       memcpy( dest, hdr->meid, RMR_MAX_MEID );
 
        return dest;
 }
@@ -412,3 +464,4 @@ extern unsigned char* rmr_get_srcip( rmr_mbuf_t* msg, unsigned char* dest ) {
 
        return rstr;
 }
+