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[Listener] Radiotap header is little-endian! 

Use le16toh() instead of ntohs() for rtap header length.
This commit is contained in:
Matteo Cypriani 2010-11-19 19:23:10 +01:00
parent 0a8ef2793b
commit 2e16e62c44
2 changed files with 14 additions and 10 deletions
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13
infrastructure-centred/owlps-listener/owlps-listener.h
View File

@ -28,8 +28,8 @@
#endif // USE_PTHREAD
#include <endian.h>
/* <endian.h> defines le32toh only in glibc >= 2.9. If we use an older
* version of glibc, or another libc (e.g. uClibc), we must define it
/* <endian.h> defines le*toh only in glibc >= 2.9. If we use an older
* version of glibc, or another libc (e.g. uClibc), we must define them
* manually.
*/
#ifndef le32toh
@ -41,6 +41,15 @@
# endif // __BYTE_ORDER == __LITTLE_ENDIAN
#endif // le32toh
#ifndef le16toh
# if __BYTE_ORDER == __LITTLE_ENDIAN
# define le16toh(x) (x)
# else // __BYTE_ORDER == __LITTLE_ENDIAN
# include <byteswap.h>
# define le16toh(x) bswap_16(x)
# endif // __BYTE_ORDER == __LITTLE_ENDIAN
#endif // le16toh
// Used by get_mac_addr():
#include <netinet/if_ether.h>
#include <netinet/udp.h>

11
infrastructure-centred/owlps-listener/owlps-listenerd.c
View File

@ -498,7 +498,8 @@ void read_packet(u_char *args, const struct pcap_pkthdr *header,
// Copy 2 bytes from the 3rd data byte, that is the size of the rtap
// header (changes with the flags):
memcpy(&rtap_bytes, &data[2], sizeof(unsigned short)) ;
rtap_bytes = ntohs(rtap_bytes) ;
// Radiotap header is little-endian
rtap_bytes = le16toh(rtap_bytes) ;
// After the rtap header, there is the 802.11 header; the first byte
// is the packet type (beacon or not):
@ -654,13 +655,7 @@ void read_packet(u_char *args, const struct pcap_pkthdr *header,
// Get rtap flags:
memcpy(&rtap_presentflags,
&data[RTAP_P_PRESENTFLAGS], RTAP_L_PRESENTFLAGS) ;
/* We get the flags in big-endian (net-endianess), but we work on them
* as if it was in little-endian. This allows to declare an array of 15
* bits (instead of 32), because we work only on the least significant
* bits (and so we do not reserve space for most significant bits that
* are useless). It's kind of cheat :-)
* So, on big-endian architectures, we must inverse bits as if we had
* got flags in little-endian: */
// Radiotap header is little-endian
rtap_presentflags = le32toh(rtap_presentflags) ;
for (i = 0 ; i < 15 ; i++) // Initialise present flags structure