Is this a portable implementation?
#if defined(BIG_ENDIAN) && !defined(LITTLE_ENDIAN)
#define htons(A) (A)
#define htonl(A) (A)
#define ntohs(A) (A)
#define ntohl(A) (A)
#elif defined(LITTLE_ENDIAN) && !defined(BIG_ENDIAN)
#define htons(A) ((((uint16)(A) & 0xff00) >> 8) | \
(((uint16)(A) & 0x00ff) << 8))
#define htonl(A) ((((uint32)(A) & 0xff000000) >> 24) | \
(((uint32)(A) & 0x00ff0000) >> 8) | \
(((uint32)(A) & 0x0000ff00) << 8) | \
(((uint32)(A) & 0x000000ff) << 24))
#define ntohs htons
#define ntohl htohl
#else
#error "Either BIG_ENDIAN or LITTLE_ENDIAN must be #defined, but not both."
#endif